@article{kuznetsov_2024, title={Lewy body radius growth: The hypothesis of the cube root of time dependency}, volume={581}, ISSN={["1095-8541"]}, DOI={10.1016/j.jtbi.2024.111734}, abstractNote={This paper presents a model for the growth of Lewy bodies (LBs), which are pathological hallmarks of Parkinson's disease (PD). The model simulates the growth of classical LBs, consisting of a core and a halo. The core is assumed to comprise lipid membrane fragments and damaged organelles, while the halo consists of radiating alpha-synuclein (α-syn) fibrils. The Finke-Watzky model is employed to simulate the aggregation of lipid fragments and α-syn monomers. Analytical and numerical exploration of the governing equations yielded approximate solutions applicable for larger times. The application of these approximate solutions to simulate LB radius growth led to the discovery of the cube root hypothesis, which posits that the LB radius is proportional to the cube root of its growth time. Sensitivity analysis revealed that the LB radius is unaffected by the kinetic rates of nucleation and autocatalytic growth, with growth primarily regulated by the production rates of lipid membrane fragments and α-syn monomers. The model indicates that the formation of large LBs associated with PD is dependent on the malfunction of the machinery responsible for the degradation of lipid membrane fragments, α-syn monomers, and their aggregates.}, journal={JOURNAL OF THEORETICAL BIOLOGY}, author={Kuznetsov, Andrey V.}, year={2024}, month={Mar} }
@article{kuznetsov_2024, title={Numerical and Analytical Simulation of the Growth of Amyloid-β Plaques}, volume={146}, ISSN={["1528-8951"]}, DOI={10.1115/1.4064969}, abstractNote={Abstract Numerical and analytical solutions were employed to calculate the radius of an amyloid-β (Aβ) plaque over time. To the author's knowledge, this study presents the first model simulating the growth of Aβ plaques. Findings indicate that the plaque can attain a diameter of 50 μm after 20 years of growth, provided the Aβ monomer degradation machinery is malfunctioning. A mathematical model incorporates nucleation and autocatalytic growth processes using the Finke–Watzky model. The resulting system of ordinary differential equations was solved numerically, and for the simplified case of infinitely long Aβ monomer half-life, an analytical solution was found. Assuming that Aβ aggregates stick together and using the distance between the plaques as an input parameter of the model, it was possible to calculate the plaque radius from the concentration of Aβ aggregates. This led to the “cube root hypothesis,” positing that Aβ plaque size increases proportionally to the cube root of time. This hypothesis helps explain why larger plaques grow more slowly. Furthermore, the obtained results suggest that the plaque size is independent of the kinetic constants governing Aβ plaque agglomeration, indicating that the kinetics of Aβ plaque agglomeration is not a limiting factor for plaque growth. Instead, the plaque growth rate is limited by the rates of Aβ monomer production and degradation.}, number={6}, journal={JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME}, author={Kuznetsov, Andrey V.}, year={2024}, month={Jun} }
@article{kuznetsov_2024, title={Numerical modeling of senile plaque development under conditions of limited diffusivity of amyloid-β monomers}, volume={587}, ISSN={["1095-8541"]}, DOI={10.1016/j.jtbi.2024.111823}, abstractNote={This paper introduces a new model to simulate the progression of senile plaques, focusing on scenarios where concentrations of amyloid beta (Aβ) monomers and aggregates vary between neurons. Extracellular variations in these concentrations may arise due to limited diffusivity of Aβ monomers and a high rate of Aβ monomer production at lipid membranes, requiring a substantial concentration gradient for diffusion-driven transport of Aβ monomers. The dimensionless formulation of the model is presented, which identifies four key dimensionless parameters governing the solutions for Aβ monomer and aggregate concentrations, as well as the radius of a growing Aβ plaque within the control volume. These parameters include the dimensionless diffusivity of Aβ monomers, the dimensionless rate of Aβ monomer production, and the dimensionless half-lives of Aβ monomers and aggregates. A dimensionless parameter is then introduced to evaluate the validity of the lumped capacitance approximation. An approximate solution is derived for the scenario involving large diffusivity of Aβ monomers and dysfunctional protein degradation machinery, resulting in infinitely long half-lives for Aβ monomers and aggregates. In this scenario, the concentrations of Aβ aggregates and the radius of the Aβ plaque depend solely on a single dimensionless parameter that characterizes the rate of Aβ monomer production. According to the approximate solution, the concentration of Aβ aggregates is linearly dependent on the rate of monomer production, and the radius of an Aβ plaque is directly proportional to the cube root of the rate of monomer production. However, when departing from the conditions of the approximate solution (e.g., finite half-lives), the concentrations of Aβ monomers and aggregates, along with the plaque radius, exhibit complex dependencies on all four dimensionless parameters. For instance, under physiological half-life conditions, the plaque radius reaches a maximum value and stabilizes thereafter.}, journal={JOURNAL OF THEORETICAL BIOLOGY}, author={Kuznetsov, Andrey V}, year={2024}, month={Jun} }
@article{v. kuznetsov_2024, title={The growth rate of senile plaques is determined by the competition between the rate of deposition of free Aβ aggregates into plaques and the autocatalytic production of free Aβ aggregates}, volume={593}, ISSN={["1095-8541"]}, DOI={10.1016/j.jtbi.2024.111900}, abstractNote={The formation of amyloid beta (Aβ) deposits (senile plaques) is one of the hallmarks of Alzheimer's disease (AD). This study investigates what processes are primarily responsible for their formation. A model is developed to simulate the diffusion of amyloid beta (Aβ) monomers, the production of free Aβ aggregates through nucleation and autocatalytic processes, and the deposition of these aggregates into senile plaques. The model suggests that efficient degradation of Aβ monomers alone may suffice to prevent the growth of senile plaques, even without degrading Aβ aggregates and existing plaques. This is because the degradation of Aβ monomers interrupts the supply of reactants needed for plaque formation. The impact of Aβ monomer diffusivity is demonstrated to be small, enabling the application of the lumped capacitance approximation and the derivation of approximate analytical solutions for limiting cases with both small and large rates of Aβ aggregate deposition into plaques. It is found that the rate of plaque growth is governed by two competing processes. One is the deposition rate of free Aβ aggregates into senile plaques. If this rate is small, the plaque grows slowly. However, if the rate of deposition of Aβ aggregates into senile plaques is very large, the free Aβ aggregates are removed from the intracellular fluid by deposition into the plaques, leaving insufficient free Aβ aggregates to catalyze the production of new aggregates. This suggests that under certain conditions, Aβ plaques may offer neuroprotection and impede their own growth. Additionally, it indicates that there exists an optimal rate of deposition of free Aβ aggregates into the plaques, at which the plaques attain their maximum size.}, journal={JOURNAL OF THEORETICAL BIOLOGY}, author={V. Kuznetsov, Andrey}, year={2024}, month={Oct} }
@article{kuznetsov_kuznetsov_2023, title={ATP diffusional gradients are sufficient to maintain bioenergetic homeostasis in synaptic boutons lacking mitochondria}, ISSN={["2040-7947"]}, DOI={10.1002/cnm.3696}, abstractNote={Abstract}, journal={INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING}, author={Kuznetsov, Ivan A. and Kuznetsov, Andrey V.}, year={2023}, month={Mar} }
@article{vanblunk_srikanth_pandit_kuznetsov_brudno_2023, title={Absorption rate governs cell transduction in dry macroporous scaffolds}, volume={1}, ISSN={["2047-4849"]}, DOI={10.1039/d2bm01753a}, abstractNote={Dry, macroporous scaffolds efficiently transduce T cells, but the mechanism for this transduction has not been studied previously. We report that liquid volume and resultant differences in liquid absorption rates governs cell transduction efficiency.}, journal={BIOMATERIALS SCIENCE}, author={VanBlunk, Madelyn and Srikanth, Vishal and Pandit, Sharda S. and Kuznetsov, Andrey V. and Brudno, Yevgeny}, year={2023}, month={Jan} }
@article{kuznetsov_kuznetsov_2023, title={Dynein Dysfunction Prevents Maintenance of High Concentrations of Slow Axonal Transport Cargos at the Axon Terminal: A Computational Study}, volume={145}, ISSN={["1528-8951"]}, DOI={10.1115/1.4056915}, abstractNote={Abstract}, number={7}, journal={JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME}, author={Kuznetsov, Ivan A. and Kuznetsov, Andrey V.}, year={2023}, month={Jul} }
@article{kuznetsov_kuznetsov_2023, title={Effect of mitochondrial circulation on mitochondrial age density distribution}, ISSN={["2040-7947"]}, DOI={10.1002/cnm.3770}, abstractNote={Abstract}, journal={INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING}, author={Kuznetsov, Ivan A. and Kuznetsov, Andrey V.}, year={2023}, month={Sep} }
@article{srikanth_peverall_kuznetsov_2023, title={Flow Regimes and Types of Solid Obstacle Surface Roughness in Turbulent Heat Transfer Inside Periodic Porous Media}, ISSN={["1573-1634"]}, DOI={10.1007/s11242-023-01978-6}, abstractNote={The role of solid obstacle surface roughness in turbulent convection in porous media is not well understood, even though it is frequently used for heat transfer enhancement in many applications. The focus of this paper is to systematically study the influence of solid obstacle surface roughness in porous media on the microscale flow physics and report its effect on macroscale drag and Nusselt number. The Reynolds-averaged flow field is numerically simulated using the realizable k-ε model for a flow through a periodic porous medium consisting of an in-line arrangement of square cylinders with square roughness particles on the cylinder surface. Two flow regimes are identified with respect to the surface roughness particle height—fine and coarse roughness regimes. The effect of the roughness particles in the fine roughness regime is limited to the near-wall boundary layer around the solid obstacle surface. In the coarse roughness regime, the roughness particles modify the microscale flow field in the entire pore space of the porous medium. In the fine roughness regime, the heat transfer from the rough solid obstacles to the fluid inside the porous medium is less than that from a smooth solid obstacle. In the coarse roughness regime, there is an enhancement in the heat transfer from the rough solid obstacle to the fluid inside the porous medium. Total drag reduction is also observed in the fine roughness regime for the smallest roughness particle height. The surface roughness particle spacing determines the fractional area of the solid obstacle surface covered by recirculating, reattached, and stagnating flow. As the roughness particle spacing increases, there are two competing factors for the heat transfer rate—increase due to more surface area covered by reattached flow and decrease due to fewer roughness particles on the solid obstacle surface. Decreasing the porosity and increasing the Reynolds number amplify the effect of the surface roughness on the microscale flow. The results suggest that heat transfer in porous media can be enhanced, if the increase in drag can be overcome. The results also show that the fine roughness regime, which is frequently encountered due to corrosion, is detrimental to the heat transfer performance of porous media.}, journal={TRANSPORT IN POROUS MEDIA}, author={Srikanth, Vishal and Peverall, Dylan and Kuznetsov, Andrey V.}, year={2023}, month={Jul} }
@article{kuznetsov_kuznetsov_2023, title={Mitochondrial transport in symmetric and asymmetric axons with multiple branching junctions: a computational study}, ISSN={["1476-8259"]}, DOI={10.1080/10255842.2023.2226787}, abstractNote={AbstractAbstractMitochondrial aging has been proposed to be involved in a variety of neurodegenerative disorders, such as Parkinson's disease. Here, we explore the impact of multiple branching junctions in axons on the mean age of mitochondria and their age density distributions in demand sites. The study examined mitochondrial concentration, mean age, and age density distribution in relation to the distance from the soma. We developed models for a symmetric axon containing 14 demand sites and an asymmetric axon containing 10 demand sites. We investigated how the concentration of mitochondria changes when an axon splits into two branches at the branching junction. Additionally, we studied whether mitochondrial concentrations in the branches are affected by what proportion of mitochondrial flux enters the upper branch versus the lower branch. Furthermore, we explored whether the distributions of mitochondrial mean age and age density in branching axons are affected by how the mitochondrial flux splits at the branching junction. When the mitochondrial flux is unevenly split at the branching junction of an asymmetric axon, with a greater proportion of the flux entering the longer branch, the average age of mitochondria (system age) in the axon increases. Our findings elucidate the effects of axonal branching on the mitochondrial age.Keywords: Neurodegenerationmitochondrial agingParkinson's diseaselarge axonal arborscomputational biology Disclosure statementNo potential conflict of interest was reported by the authors.Additional informationFundingIAK acknowledges the fellowship support of the Paul and Daisy Soros Fellowship for New Americans and the NIH/National Institute of Mental Health (NIMH) Ruth L. Kirchstein NRSA (F30 MH122076-01). AVK acknowledges the support of the National Science Foundation (award CBET-2042834) and the Alexander von Humboldt Foundation through the Humboldt Research Award.}, journal={COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING}, author={Kuznetsov, Ivan A. and Kuznetsov, Andrey V.}, year={2023}, month={Jun} }
@article{kuznetsov_kuznetsov_2023, title={Why slow axonal transport is bidirectional - can axonal transport of tau protein rely only on motor-driven anterograde transport?}, ISSN={["1476-8259"]}, DOI={10.1080/10255842.2023.2197541}, abstractNote={Slow axonal transport (SAT) moves multiple proteins from the soma, where they are synthesized, to the axon terminal. Due to the great lengths of axons, SAT almost exclusively relies on active transport, which is driven by molecular motors. The puzzling feature of slow axonal transport is its bidirectionality. Although the net direction of SAT is anterograde, from the soma to the terminal, experiments show that it also contains a retrograde component. One of the proteins transported by SAT is the microtubule-associated protein tau. To better understand why the retrograde component in tau transport is needed, we used the perturbation technique to analyze how the full tau SAT model can be simplified for the specific case when retrograde motor-driven transport and diffusion-driven transport of tau are negligible and tau is driven only by anterograde (kinesin) motors. The solution of the simplified equations shows that without retrograde transport the tau concentration along the axon length stays almost uniform (decreases very slightly), which is inconsistent with the experimenal tau concentration at the outlet boundary (at the axon tip). Thus kinesin-driven transport alone is not enough to explain the empirically observed distribution of tau, and the retrograde motor-driven component in SAT is needed.}, journal={COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING}, author={Kuznetsov, Ivan A. A. and Kuznetsov, Andrey V. V.}, year={2023}, month={Mar} }
@article{kuznetsov_kuznetsov_2022, title={An analytical solution simulating growth of Lewy bodies}, ISSN={["1477-8602"]}, DOI={10.1093/imammb/dqac006}, abstractNote={Abstract}, journal={MATHEMATICAL MEDICINE AND BIOLOGY-A JOURNAL OF THE IMA}, author={Kuznetsov, Ivan A. and Kuznetsov, Andrey V}, year={2022}, month={Jun} }
@article{kuznetsov_kuznetsov_2022, title={Bidirectional, unlike unidirectional transport, allows transporting axonal cargos against their concentration gradient}, volume={546}, ISSN={["1095-8541"]}, DOI={10.1016/j.jtbi.2022.111161}, abstractNote={Even though most axonal cargos are synthesized in the soma, the concentration of many of these cargos is larger at the presynaptic terminal than in the soma. This requires transport of these cargos from the soma to the presynaptic terminal or other active sites in the axon. Axons utilize both bidirectional (for example, slow axonal transport) and unidirectional (for example, fast anterograde axonal transport) modes of cargo transport. Bidirectional transport seems to be less efficient because it requires more time and takes more energy to deliver cargos. In this paper, we studied a family of models which differ by the modes of axonal cargo transport (such as anterograde and retrograde motor-driven transport and passive diffusion) as well as by the presence or absence of pausing states. The models are studied to investigate their ability to describe axonal transport against the cargo concentration gradient. We argue that bidirectional axonal transport is described by a higher-order mathematical model, which allows imposing cargo concentration not only at the axon hillock but also at the axon terminal. The unidirectional transport model allows only for the imposition of cargo concentration at the axon hillock. Due to the great lengths of the axons, anterograde transport mostly relies on molecular motors, such as kinesins, to deliver cargos synthesized in the soma to the terminal and other active sites in the axon. Retrograde transport can be also motor-driven, in which case cargos are transported by dynein motors. If cargo concentration at the axon tip is higher than at the axon hillock, retrograde transport can also occur by cargo diffusion. However, because many axonal cargos are large or they assemble in multiprotein complexes for axonal transport, the diffusivity of such cargos is very small. We investigated the case of a small cargo diffusivity using a perturbation technique and found that for this case the effect of diffusion is limited to a very thin diffusion boundary layer near the axon tip. If cargo diffusivity is decreased in the model, we show that without motor-driven retrograde transport the model is unable to describe a high cargo concentration at the axon tip. To the best of our knowledge, our paper presents the first explanation for the utilization of seemingly inefficient bidirectional transport in neurons.}, journal={JOURNAL OF THEORETICAL BIOLOGY}, author={Kuznetsov, Ivan A. and Kuznetsov, Andrey V}, year={2022}, month={Aug} }
@article{kuznetsov_kuznetsov_2022, title={Can the lack of fibrillar form of alpha-synuclein in Lewy bodies be explained by its catalytic activity?}, volume={344}, ISSN={["1879-3134"]}, DOI={10.1016/j.mbs.2021.108754}, abstractNote={Finding the causative pathophysiological mechanisms for Parkinson’s disease (PD) is important for developing therapeutic interventions. Until recently, it was believed that Lewy bodies (LBs), the hallmark of PD, are mostly composed of alpha-synuclein (α-syn) fibrils. Recent results (Shahmoradian et al. (2019)) demonstrated that the fibrillar form of α-syn is lacking from LBs. Here we propose that this surprising observation can be explained by the catalytic activity of the fibrillar form of α-syn. We assumed that α-syn fibrils catalyze the formation of LBs, but do not become part of them. We developed a mathematical model based on this hypothesis. By using the developed model, we investigated the consequences of this hypothesis. In particular, the model suggests that the long incubation time of PD can be explained by a two-step aggregation process that leads to its development: (i) aggregation of monomeric α-syn into α-syn oligomers and fibrils and (ii) clustering of membrane-bound organelles, which may cause disruption of axonal trafficking and lead to neuron starvation and death. The model shows that decreasing the rate of destruction of α-syn aggregates in somatic lysosomes accelerates the formation of LBs. Another consequence of the model is the prediction that removing α-syn aggregates from the brain after the aggregation of membrane-bound organelles into LBs has started may not stop the progression of PD because LB formation is an autocatalytic process; hence, the formation of LBs will be catalyzed by aggregates of membrane-bound organelles even in the absence of α-syn aggregates. The performed sensitivity study made it possible to establish the hierarchy of model parameters with respect to their effect on the formation of vesicle aggregates in the soma.}, journal={MATHEMATICAL BIOSCIENCES}, author={Kuznetsov, Ivan A. and Kuznetsov, Andrey V}, year={2022}, month={Feb} }
@article{kuznetsov_kuznetsov_2022, title={Computation of the mitochondrial age distribution along the axon length}, ISSN={["1476-8259"]}, DOI={10.1080/10255842.2022.2128784}, abstractNote={We describe a compartmental model of mitochondrial transport in axons, which we apply to compute mitochondrial age at different distances from the soma. The model predicts that at the tip of an axon that has a length of 1 cm, the average mitochondrial age is approximately 22 hours. The mitochondria are youngest closest to the soma and their age scales approximately linearly with distance from the soma. To the best of the authors’ knowledge, this is the first attempt to predict the spatial distribution of mitochondrial age within an axon. A sensitivity study of the mean age of mitochondria to various model parameters is also presented.}, journal={COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING}, author={Kuznetsov, Ivan A. and Kuznetsov, Andrey V}, year={2022}, month={Sep} }
@article{kuznetsov_kuznetsov_2022, title={Effects of axon branching and asymmetry between the branches on transport, mean age, and age density distributions of mitochondria in neurons: A computational study}, ISSN={["2040-7947"]}, DOI={10.1002/cnm.3648}, abstractNote={Abstract}, journal={INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING}, author={Kuznetsov, Ivan A. and Kuznetsov, Andrey V}, year={2022}, month={Oct} }
@article{gasow_kuznetsov_jin_2022, title={Prediction of pore-scale-property dependent natural convection in porous media at high Rayleigh numbers}, volume={179}, ISSN={["1778-4166"]}, DOI={10.1016/j.ijthermalsci.2022.107635}, abstractNote={Natural convection in porous media has received increasing attention in recent years due to its significance in engineering applications. This process is traditionally analyzed by the solution of the classical Darcy-Oberbeck-Boussinesq (DOB) equations. According to the DOB equations, natural convection in porous media is exclusively dependent on the Rayleigh-Darcy number, Ra, while the Sherwood number, Sh, has a linear relationship with Ra at high Rayleigh numbers. However, these predictions conflict with experimental observations. In this study, we have performed a pore-scale resolved direct numerical simulation (DNS) study of natural convection in periodic porous media composed of two-dimensional square and circular obstacles. Based on our analysis, a new correlation of Sh for large Rayleigh numbers (Ra≥1000), low Darcy numbers Da, and high Schmidt numbers Sc (Da/Sc≤2×10−8) has been proposed, expressed as Sh=aRa1−0.2φ2+1, where a=0.011±0.002 is a pore-scale geometric parameter. The new correlation has been validated over a wide range of Rayleigh numbers, porosity values, and pore-scale geometries. Our DNS results also show that, with a decrease of porosity, it becomes more difficult for mega-plumes with low wavenumbers to enter the boundary layer. Low wavenumber motions decay much faster with a decrease of Da than the pore-scale motions near the wall. The volume-averaged dissipation rate nondimensionalized using the pore size εˆi has the scaling law εˆi∼Da in the internal region and εˆi∼Da1/2 in the near-wall region. We expect that these characteristics obtained from DNS also apply to natural convection in porous media with much lower Darcy numbers.}, journal={INTERNATIONAL JOURNAL OF THERMAL SCIENCES}, author={Gasow, Stefan and Kuznetsov, Andrey V. and Jin, Yan}, year={2022}, month={Sep} }
@article{huang_srikanth_kuznetsov_2022, title={The evolution of turbulent micro-vortices and their effect on convection heat transfer in porous media}, volume={942}, ISSN={["1469-7645"]}, DOI={10.1017/jfm.2022.291}, abstractNote={New insight into the contribution of the microscale vortex evolution to convection heat transfer in porous media is presented in this paper. The objective is to determine how the microscale vortices influence convection heat transfer in turbulent flow inside porous media. The microscale temperature distribution is analysed using flow visualization in two dimensions using streamlines and in three dimensions using the Q-criterion. The pertinent observations are supplemented with a comparison of surface skin friction and heat transfer using: (i) surface skin-friction lines and (ii) the joint probability density function of the pressure and skin-friction coefficients, along with the Nusselt number. The microscale flow phenomena observed are corroborated with the features of the frequency spectra of the drag coefficient and macroscale Nusselt number. The large eddy simulation technique is used in this study to investigate the flow field inside a periodic porous medium. The Reynolds numbers of the flow are 300 and 500. The porous medium consists of solid obstacles in the shape of square and circular cylinders. Two distinct flow regimes are represented by using the porosities of 0.50 and 0.87. The results show that the surface Nusselt number distribution is dependent on whether the micro-vortices are attached to or detached from the surface of the obstacle. The spectra of the macroscale Nusselt number and the pressure drag are similar, signifying a correlation between the dynamics of heat transfer and the microscale turbulent structures. Both vortex shedding and secondary flow instabilities are observed that significantly influence the Nusselt number. The fundamental insight gained in this paper can inform the development of more robust macroscale models of convection heat transfer in turbulent flow in porous media.}, journal={JOURNAL OF FLUID MECHANICS}, author={Huang, Ching-Wei and Srikanth, Vishal and Kuznetsov, Andrey V}, year={2022}, month={May} }
@article{gasow_kuznetsov_avila_jin_2021, title={A macroscopic two-length-scale model for natural convection in porous media driven by a species-concentration gradient}, volume={926}, ISSN={["1469-7645"]}, DOI={10.1017/jfm.2021.691}, abstractNote={The modelling of natural convection in porous media is receiving increased interest due to its significance in environmental and engineering problems. State-of-the-art simulations are based on the classic macroscopic Darcy–Oberbeck–Boussinesq (DOB) equations, which are widely accepted to capture the underlying physics of convection in porous media provided the Darcy number,
$Da$
, is small. In this paper we analyse and extend the recent pore-resolved direct numerical simulations (DNS) of Gasow et al. (J. Fluid Mech, vol. 891, 2020, p. A25) and show that the macroscopic diffusion, which is neglected in DOB, is of the same order (with respect to
$Da$
) as the buoyancy force and the Darcy drag. Consequently, the macroscopic diffusion must be modelled even if the value of
$Da$
is small. We propose a ‘two-length-scale diffusion’ model, in which the effect of the pore scale on the momentum transport is approximated with a macroscopic diffusion term. This term is determined by both the macroscopic length scale and the pore scale. It includes a transport coefficient that solely depends on the pore-scale geometry. Simulations of our model render a more accurate Sherwood number, root mean square (r.m.s.) of the mass concentration and r.m.s. of the velocity than simulations that employ the DOB equations. In particular, we find that the Sherwood number
$Sh$
increases with decreasing porosity and with increasing Schmidt number
$(Sc)$
. In addition, for high values of
$Ra$
and high porosities,
$Sh$
scales nonlinearly. These trends agree with the DNS, but are not captured in the DOB simulations.}, journal={JOURNAL OF FLUID MECHANICS}, author={Gasow, Stefan and Kuznetsov, Andrey V. and Avila, Marc and Jin, Yan}, year={2021}, month={Sep} }
@article{kuznetsov_kuznetsov_2021, title={Simulation of a sudden drop-off in distal dense core vesicle concentration in Drosophila type II motoneuron terminals}, ISSN={["2040-7947"]}, DOI={10.1002/cnm.3523}, abstractNote={Abstract}, journal={INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING}, author={Kuznetsov, Ivan A. and Kuznetsov, Andrey V}, year={2021}, month={Sep} }
@article{srikanth_huang_su_kuznetsov_2021, title={Symmetry breaking of turbulent flow in porous media composed of periodically arranged solid obstacles}, volume={929}, ISSN={["1469-7645"]}, DOI={10.1017/jfm.2021.813}, abstractNote={The focus of this paper is a numerical simulation study of the flow dynamics in a periodic porous medium to analyse the physics of a symmetry-breaking phenomenon, which causes a deviation in the direction of the macroscale flow from that of the applied pressure gradient. The phenomenon is prominent in the range of porosity from 0.43 to 0.72 for circular solid obstacles. It is the result of the flow instabilities formed when the surface forces on the solid obstacles compete with the inertial force of the fluid flow in the turbulent regime. We report the origin and mechanism of the symmetry-breaking phenomenon in periodic porous media. Large-eddy simulation (LES) is used to simulate turbulent flow in a homogeneous porous medium consisting of a periodic, square lattice arrangement of cylindrical solid obstacles. Direct numerical simulation is used to simulate the transient stages during symmetry breakdown and also to validate the LES method. Quantitative and qualitative observations are made from the following approaches: (1) macroscale momentum budget and (2) two- and three-dimensional flow visualization. The phenomenon draws its roots from the amplification of a flow instability that emerges from the vortex shedding process. The symmetry-breaking phenomenon is a pitchfork bifurcation that can exhibit multiple modes depending on the local vortex shedding process. The phenomenon is observed to be sensitive to the porosity, solid obstacle shape and Reynolds number. It is a source of macroscale turbulence anisotropy in porous media for symmetric solid-obstacle geometries. In the macroscale, the principal axis of the Reynolds stress tensor is not aligned with any of the geometric axes of symmetry, nor with the direction of flow. Thus, symmetry breaking in porous media involves unresolved flow physics that should be taken into consideration while modelling flow inhomogeneity in the macroscale.}, journal={JOURNAL OF FLUID MECHANICS}, author={Srikanth, Vishal and Huang, Ching-Wei and Su, Timothy S. and Kuznetsov, Andrey V}, year={2021}, month={Oct} }
@article{gasow_lin_zhang_kuznetsov_avila_jin_2020, title={Effects of pore scale on the macroscopic properties of natural convection in porous media}, volume={891}, ISSN={["1469-7645"]}, DOI={10.1017/jfm.2020.164}, abstractNote={Natural convection in porous media is a fundamental process for the long-term storage of CO2 in deep saline aquifers. Typically, details of mass transfer in porous media are inferred from the numerical solution of the volume-averaged Darcy–Oberbeck–Boussinesq (DOB) equations, even though these equations do not account for the microscopic properties of a porous medium. According to the DOB equations, natural convection in a porous medium is uniquely determined by the Rayleigh number. However, in contrast with experiments, DOB simulations yield a linear scaling of the Sherwood number with the Rayleigh number (
$Ra$
) for high values of
$Ra$
(
$Ra\gg 1300$
). Here, we perform direct numerical simulations (DNS), fully resolving the flow field within the pores. We show that the boundary layer thickness is determined by the pore size instead of the Rayleigh number, as previously assumed. The mega- and proto-plume sizes increase with the pore size. Our DNS results exhibit a nonlinear scaling of the Sherwood number at high porosity, and for the same Rayleigh number, higher Sherwood numbers are predicted by DNS at lower porosities. It can be concluded that the scaling of the Sherwood number depends on the porosity and the pore-scale parameters, which is consistent with experimental studies.}, journal={JOURNAL OF FLUID MECHANICS}, author={Gasow, Stefan and Lin, Zhe and Zhang, Hao Chun and Kuznetsov, Andrey V and Avila, Marc and Jin, Yan}, year={2020}, month={May} }
@article{kuznetsov_kuznetsov_2020, title={How old are dense-core vesicles residing in en passant boutons: simulation of the mean age of dense-core vesicles in axonal arbours accounting for resident and transiting vesicle populations}, volume={476}, ISSN={["1471-2946"]}, DOI={10.1098/rspa.2020.0454}, abstractNote={
In neurons, neuropeptides are synthesized in the soma and are then transported along the axon in dense-core vesicles (DCVs). DCVs are captured in varicosities located along the axon terminal called
en passant
boutons, which are active terminal sites that accumulate and release neurotransmitters. Recently developed experimental techniques allow for the estimation of the age of DCVs in various locations in the axon terminal. Accurate simulation of the mean age of DCVs in boutons requires the development of a model that would account for resident, transiting-anterograde and transiting-retrograde DCV populations. In this paper, such a model is developed. The model is applied to simulating DCV transport in
Drosophila
type II motoneurons. The model simulates DCV transport and capture in the axon terminals and makes it possible to predict the age density distribution of DCVs in
en passant
boutons as well as DCV mean age in boutons. The predicted prevalence of older organelles in distal boutons may explain the ‘dying back’ pattern of axonal degeneration observed in dopaminergic neurons in Parkinson's disease. The predicted difference of two hours between the age of older DCVs residing in distal boutons and the age of younger DCVs residing in proximal boutons is consistent with an approximate estimate of age difference deduced from experimental observations. The age density of resident DCVs is found to be bimodal, which is because DCVs are captured from two transiting states: the anterograde transiting state that contains younger DCVs and the retrograde transiting state that contains older DCVs.
}, number={2241}, journal={PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES}, author={Kuznetsov, Ivan A. and Kuznetsov, Andrey V.}, year={2020}, month={Sep} }
@article{kuznetsov_kuznetsov_2020, title={Modeling tau transport in the axon initial segment}, volume={329}, ISSN={["1879-3134"]}, DOI={10.1016/j.mbs.2020.108468}, abstractNote={By assuming that tau protein can be in seven kinetic states, we developed a model of tau protein transport in the axon and in the axon initial segment (AIS). Two separate sets of kinetic constants were determined, one in the axon and the other in the AIS. This was done by fitting the model predictions in the axon with experimental results and by fitting the model predictions in the AIS with the assumed linear increase of the total tau concentration in the AIS. The calibrated model was used to make predictions about tau transport in the axon and in the AIS. To the best of our knowledge, this is the first paper that presents a mathematical model of tau transport in the AIS. Our modeling results suggest that binding of free tau to microtubules creates a negative gradient of free tau in the AIS. This leads to diffusion-driven tau transport from the soma into the AIS. The model further suggests that slow axonal transport and diffusion-driven transport of tau work together in the AIS, moving tau anterogradely. Our numerical results predict an interplay between these two mechanisms: as the distance from the soma increases, the diffusion-driven transport decreases, while motor-driven transport becomes larger. Thus, the machinery in the AIS works as a pump, moving tau into the axon.}, journal={MATHEMATICAL BIOSCIENCES}, author={Kuznetsov, Ivan A. and Kuznetsov, Andrey V}, year={2020}, month={Nov} }
@article{rao_kuznetsov_jin_2020, title={Numerical Modeling of Momentum Dispersion in Porous Media Based on the Pore Scale Prevalence Hypothesis}, volume={133}, ISSN={["1573-1634"]}, DOI={10.1007/s11242-020-01423-y}, abstractNote={Abstract}, number={2}, journal={TRANSPORT IN POROUS MEDIA}, author={Rao, Feixiong and Kuznetsov, Andrey V and Jin, Yan}, year={2020}, month={Jun}, pages={271–292} }
@article{fleischman_kaskar_shams_zhang_olson_zdanski_thorp_kuznetsov_grace_lee_2019, title={A Novel Porcine Model for the Study of Cerebrospinal Fluid Dynamics: Development and Preliminary Results}, volume={10}, ISSN={["1664-2295"]}, DOI={10.3389/fneur.2019.01137}, abstractNote={Idiopathic intracranial hypertension, space-flight associated neuro-ocular syndrome (SANS), and glaucoma are conditions that are among a spectrum of cerebrospinal fluid (CSF)-related ophthalmologic disease. This implies that local CSF pressures at the level of the optic nerve are involved to variable extent in these disease processes. However, CSF pressure measurements are problematic due to invasiveness and interpretation. The pressure measured by a lumbar puncture is likely not the same as the orbital CSF pressure. It is believed this is at least in part due to the flow restrictive properties of the optic canal. To investigate CSF flow within the orbit, a model for CSF dynamics was created using three medium-sized pigs. Contrast was administered through a lumbar subarachnoid space access. The contrast front was imaged with repeated computed tomographic (CT) imaging. Once contrast entered the orbit, rapid, sequential CT imaging was performed until the contrast reached the posterior globe. Head tilting was performed to highlight the role of gravitational dependence within the subarachnoid space.}, journal={FRONTIERS IN NEUROLOGY}, author={Fleischman, David and Kaskar, Omkar and Shams, Rayad and Zhang, Xinxin and Olson, Daniel and Zdanski, Carlton and Thorp, Brian D. and Kuznetsov, Andrey V and Grace, Landon and Lee, Yueh Z.}, year={2019}, month={Oct} }
@article{kuznetsov_kuznetsov_2019, title={A Numerical Study of Sensitivity Coefficients for a Model of Amyloid Precursor Protein and Tubulin-Associated Unit Protein Transport and Agglomeration in Neurons at the Onset of Alzheimer's Disease}, volume={141}, ISSN={["1528-8951"]}, DOI={10.1115/1.4041905}, abstractNote={Modeling of intracellular processes occurring during the development of Alzheimer's disease (AD) can be instrumental in understanding the disease and can potentially contribute to finding treatments for the disease. The model of intracellular processes in AD, which we previously developed, contains a large number of parameters. To distinguish between more important and less important parameters, we performed a local sensitivity analysis of this model around the values of parameters that give the best fit with published experimental results. We show that the influence of model parameters on the total concentrations of amyloid precursor protein (APP) and tubulin-associated unit (tau) protein in the axon is reciprocal to the influence of the same parameters on the average velocities of the same proteins during their transport in the axon. The results of our analysis also suggest that in the beginning of AD the aggregation of amyloid-β and misfolded tau protein have little effect on transport of APP and tau in the axon, which suggests that early damage in AD may be reversible.}, number={3}, journal={JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME}, author={Kuznetsov, I. A. and Kuznetsov, A. V.}, year={2019}, month={Mar} }
@article{kaskar_fleischman_lee_thorp_kuznetsov_grace_2019, title={Identifying the Critical Factors Governing Translaminar Pressure Differential Through a Compartmental Model}, volume={60}, ISSN={["1552-5783"]}, DOI={10.1167/iovs.18-26200}, abstractNote={Purpose The effective management of glaucoma is hindered by an incomplete understanding of its pathologic mechanism. While important, intraocular pressure (IOP) alone is inadequate in explaining glaucoma. Non-IOP–mediated risk factors such as cerebrospinal fluid (CSF) pressure have been reported to contribute to glaucomatous optic neuropathy. Due to the difficulty associated with experimental measurement of the salient variables, such as the retrobulbar CSF pressure, porosity of the subarachnoid space (SAS), and especially those concerned with the perioptic SAS, there remains a limited understanding of the CSF behavior contributing to the translaminar pressure gradient (TLPG), hypothesized to be a critical factor in the development of glaucoma. Method An integrated compartmental model describing the intracranial and orbital CSF dynamics, coupled with intraocular dynamics, is developed based on first principles of fluid mechanics. A sensitivity analysis is performed to identify anatomic characteristics that significantly affect the retrobulbar subarachnoid space (RSAS) pressure and, consequently, the TLPG. Results Of the 28 parameters considered, the RSAS pressure is most sensitive to CSF flow resistance in the optic nerve SAS and the potential lymphatic outflow from the optic nerve SAS into the orbital space. A parametric study demonstrates that a combination of resistance in the range of 1.600 × 1012 − 1.930 × 1012 Pa s/m3 (200.0 − 241.3 mm Hg min/mL) with 5% to 10% lymphatic CSF outflow yields RSAS pressures that are consistent with the limited number of studies in the literature. Conclusions The results suggest that a small percentage of lymphatic CSF outflow through the optic nerve SAS is likely. In addition, flow resistance in the orbital CSF space, hypothesized to be a function of patient-specific optic nerve SAS architecture and optic canal geometry, is a critical parameter in regulating the RSAS pressure and TLPG.}, number={8}, journal={INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE}, author={Kaskar, Omkar G. and Fleischman, David and Lee, Yueh Z. and Thorp, Brian D. and Kuznetsov, Andrey V. and Grace, Landon}, year={2019}, month={Jul}, pages={3204–3214} }
@article{kuznetsov_kuznetsov_2019, title={Investigating sensitivity coefficients characterizing the response of a model of tau protein transport in an axon to model parameters}, volume={22}, ISSN={["1476-8259"]}, DOI={10.1080/10255842.2018.1534233}, abstractNote={Abstract Evaluating the sensitivity of biological models to various model parameters is a critical step towards advancing our understanding of biological systems. In this paper, we investigated sensitivity coefficients for a model simulating transport of tau protein along the axon. This is an important problem due to the relevance of tau transport and agglomeration to Alzheimer’s disease and other tauopathies, such as some forms of parkinsonism. The sensitivity coefficients that we obtained characterize how strongly three observables (the tau concentration, average tau velocity, and the percentage of tau bound to microtubules) depend on model parameters. The fact that the observables strongly depend on a parameter characterizing tau transition from the retrograde to the anterograde kinetic states suggests the importance of motor-driven transport of tau. The observables are sensitive to kinetic constants characterizing tau concentration in the free (cytosolic) state only at small distances from the soma. Cytosolic tau can only be transported by diffusion, suggesting that diffusion-driven transport of tau only plays a role in the proximal axon. Our analysis also shows the location in the axon in which an observable has the greatest sensitivity to a certain parameter. For most parameters, this location is in the proximal axon. This could be useful for designing an experiment aimed at determining the value of this parameter. We also analyzed sensitivity of the average tau velocity, the total tau concentration, and the percentage of microtubule-bound tau to cytosolic diffusivity of tau and diffusivity of bound tau along the MT lattice. The model predicts that at small distances from the soma the effect of these two diffusion processes is comparable.}, number={1}, journal={COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING}, author={Kuznetsov, Ivan A. and Kuznetsov, Andrey V.}, year={2019}, month={Jan}, pages={71–83} }
@article{celli_kuznetsov_2019, title={Marangoni convection of a viscous fluid over a vibrating plate}, volume={475}, ISSN={["1471-2946"]}, DOI={10.1098/rspa.2019.0214}, abstractNote={This research presents a new insight into Marangoni convection through investigating, both numerically and analytically, the surface tension driven instability activated by a coupled effect of a vibrating plate and viscous dissipation. A horizontal, thin fluid layer is bounded from below by an impermeable, adiabatic plate that vibrates in the horizontal direction. The upper boundary is modelled by a free surface subject to a thermal boundary condition of the third kind (Robin). The internal heat generation due to viscous dissipation yields a vertical, potentially unstable temperature gradient. The linear stability analysis of the stationary terms of the basic state is performed. The perturbed flow, in the form of plane waves, is superimposed onto the basic state. The obtained system of ordinary differential equations is solved numerically by means of the Runge–Kutta method coupled with the shooting method. For the two limiting cases, the isothermal upper boundary and adiabatic upper boundary, the analytical solutions of the eigenvalue problem are obtained. The values of the critical parameter, which identifies the threshold for the onset of Marangoni convection, are presented.}, number={2227}, journal={PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES}, author={Celli, M. and Kuznetsov, A. V.}, year={2019}, month={Jul} }
@article{kuznetsov_kuznetsov_2019, title={Modelling transport and mean age of dense core vesicles in large axonal arbours}, volume={475}, ISSN={["1471-2946"]}, DOI={10.1098/rspa.2019.0284}, abstractNote={
A model simulating the transport of dense core vesicles (DCVs) in type II axonal terminals of
Drosophila
motoneurons has been developed. The morphology of type II terminals is characterized by the large number of
en passant
boutons. The lack of both scaled-up DCV transport and scaled-down DCV capture in boutons results in a less efficient supply of DCVs to distal boutons. Furthermore, the large number of boutons that DCVs pass as they move anterogradely until they reach the most distal bouton may lead to the capture of a majority of DCVs before they turn around in the most distal bouton to move in the retrograde direction. This may lead to a reduced retrograde flux of DCVs and a lack of DCV circulation in type II terminals. The developed model simulates DCV concentrations in boutons, DCV fluxes between the boutons, age density distributions of DCVs and the mean age of DCVs in various boutons. Unlike published experimental observations, our model predicts DCV circulation in type II terminals after these terminals are filled to saturation. This disagreement is likely because experimentally observed terminals were not at steady state, but rather were accumulating DCVs for later release. Our estimates show that the number of DCVs in the transiting state is much smaller than that in the resident state. DCVs travelling in the axon, rather than DCVs transiting in the terminal, may provide a reserve of DCVs for replenishing boutons after a release. The techniques for modelling transport of DCVs developed in our paper can be used to model the transport of other organelles in axons.
}, number={2228}, journal={PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES}, author={Kuznetsov, I. A. and Kuznetsov, A. V.}, year={2019}, month={Aug} }
@article{nield_kuznetsov_2019, title={The Onset of Convection in an Anisotropic Heterogeneous Porous Medium: A New Hydrodynamic Boundary Condition}, volume={127}, ISBN={1573-1634}, DOI={10.1007/s11242-018-1210-3}, number={3}, journal={TRANSPORT IN POROUS MEDIA}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2019}, month={Apr}, pages={549–558} }
@article{celli_kuznetsov_2018, title={A new hydrodynamic boundary condition simulating the effect of rough boundaries on the onset of Rayleigh-Benard convection}, volume={116}, ISSN={["1879-2189"]}, DOI={10.1016/j.ijheatmasstransfer.2017.09.052}, abstractNote={This paper introduces a new hydrodynamic boundary condition which enables the simulation of the effects caused by rough boundaries. The classical Rayleigh-Bénard stability analysis is performed here to investigate the onset of thermal convection in a parallel-plate channel with rough boundaries. The hydrodynamic boundary conditions are modified, from the classical treatment, in order to consider channel boundaries characterised by non-negligible roughness. This roughness is simulated as a shallow fluid saturated porous medium and the Saffman interface condition is thus employed to model the hydrodynamic boundary conditions. The normal mode method is employed and the obtained eigenvalue problem is solved numerically. The Principle of Exchange of Stabilities is proved and the critical values of the Rayleigh number and of the wave number are obtained.}, journal={INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER}, author={Celli, Michele and Kuznetsov, Andrey V.}, year={2018}, month={Jan}, pages={581–586} }
@article{kuznetsov_kuznetsov_2018, title={How the formation of amyloid plaques and neurofibrillary tangles may be related: a mathematical modelling study}, volume={474}, ISSN={["1471-2946"]}, DOI={10.1098/rspa.2017.0777}, abstractNote={We develop a mathematical model that enables us to investigate possible mechanisms by which two primary markers of Alzheimer's disease (AD), extracellular amyloid plaques and intracellular tangles, may be related. Our model investigates the possibility that the decay of anterograde axonal transport of amyloid precursor protein (APP), caused by toxic tau aggregates, leads to decreased APP transport towards the synapse and APP accumulation in the soma. The developed model thus couples three processes: (i) slow axonal transport of tau, (ii) tau misfolding and agglomeration, which we simulated by using the Finke–Watzky model and (iii) fast axonal transport of APP. Because the timescale for tau agglomeration is much larger than that for tau transport, we suggest using the quasi-steady-state approximation for formulating and solving the governing equations for these three processes. Our results suggest that misfolded tau most likely accumulates in the beginning of the axon. The analysis of APP transport suggests that APP will also likely accumulate in the beginning of the axon, causing an increased APP concentration in this region, which could be interpreted as a ‘traffic jam’. The APP flux towards the synapse is significantly reduced by tau misfolding, but not due to the APP traffic jam, which can be viewed as a symptom, but rather due to the reduced affinity of kinesin-1 motors to APP-transporting vesicles.}, number={2210}, journal={PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES}, author={Kuznetsov, I. A. and Kuznetsov, A. V.}, year={2018}, month={Feb} }
@article{kuznetsov_kuznetsov_2018, title={Simulating Reversibility of Dense Core Vesicles Capture in En Passant Boutons: Using Mathematical Modeling to Understand the Fate of Dense Core Vesicles in En Passant Boutons}, volume={140}, ISSN={["1528-8951"]}, DOI={10.1115/1.4038201}, abstractNote={The goal of this paper is to use mathematical modeling to investigate the fate of dense core vesicles (DCVs) captured in en passant boutons located in nerve terminals. One possibility is that all DCVs captured in boutons are destroyed, another possibility is that captured DCVs can escape and reenter the pool of transiting DCVs that move through the boutons, and a third possibility is that some DCVs are destroyed in boutons, while some reenter the transiting pool. We developed a model by applying the conservation of DCVs in various compartments composing the terminal, to predict different scenarios that emerge from the above assumptions about the fate of DCVs captured in boutons. We simulated DCV transport in type Ib and type III terminals. The simulations demonstrate that, if no DCV destruction in boutons is assumed and all captured DCVs reenter the transiting pool, the DCV fluxes evolve to a uniform circulation in a type Ib terminal at steady-state and the DCV flux remains constant from bouton to bouton. Because at steady-state the amount of captured DCVs is equal to the amount of DCVs that reenter the transiting pool, no decay of DCV fluxes occurs. In a type III terminal at steady-state, the anterograde DCV fluxes decay from bouton to bouton, while retrograde fluxes increase. This is explained by a larger capture efficiency of anterogradely moving DCVs than of retrogradely moving DCVs in type III boutons, while the captured DCVs that reenter the transiting pool are assumed to be equally split between anterogradely and retrogradely moving components. At steady-state, the physiologically reasonable assumption of no DCV destruction in boutons results in the same number of DCVs entering and leaving a nerve terminal. Because published experimental results indicate no DCV circulation in type III terminals, modeling results suggest that DCV transport in these type III terminals may not be at steady-state. To better understand the kinetics of DCV capture and release, future experiments in type III terminals at different times after DCV release (molting) may be proposed.}, number={5}, journal={JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME}, author={Kuznetsov, I. A. and Kuznetsov, A. V.}, year={2018}, month={May} }
@article{kuznetsov_kuznetsov_2018, title={Simulating the effect of formation of amyloid plaques on aggregation of tau protein}, volume={474}, ISSN={["1471-2946"]}, DOI={10.1098/rspa.2018.0511}, abstractNote={In this paper, we develop a mathematical model that enables the investigation of the production and intracellular transport of amyloid precursor protein (APP) and tau protein in a neuron. We also investigate the aggregation of APP fragments into amyloid-β (Aβ) as well as tau aggregation into tau oligomers and neurofibrillary tangles. Using the developed model, we investigate how Aβ aggregation can influence tau transport and aggregation in both the soma and the axon. We couple the Aβ and tau agglomeration processes by assuming that the value of the kinetic constant that describes the autocatalytic growth (self-replication) reaction step of tau aggregation is proportional to the Aβ concentration. The model predicts that APP and tau are distributed differently in the axon. While APP has a uniform distribution along the axon, tau's concentration first decreases and then increases towards the synapse. Aβ is uniformly produced along the axon while misfolded tau protein is mostly produced in the proximal axon. The number of Aβ and tau polymers originating from the axon is much smaller than the number of Aβ and tau polymers originating from the soma. The rate of production of misfolded tau polymers depends on how strongly their production is facilitated by Aβ.}, number={2220}, journal={PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES}, author={Kuznetsov, I. A. and Kuznetsov, A. V.}, year={2018}, month={Dec} }
@article{kuznetsov_kuznetsov_2017, title={How dense core vesicles are delivered to axon terminals - a review of modeling approaches}, journal={Modeling of Microscale Transport in Biological Processes}, author={Kuznetsov, I. A. and Kuznetsov, A. V.}, year={2017}, pages={335–352} }
@article{kuznetsov_kuznetsov_2017, title={Simulating tubulin-associated unit transport in an axon: using bootstrapping for estimating confidence intervals of best-fit parameter values obtained from indirect experimental data}, volume={473}, ISSN={["1471-2946"]}, DOI={10.1098/rspa.2017.0045}, abstractNote={In this paper, we first develop a model of axonal transport of tubulin-associated unit (tau) protein. We determine the minimum number of parameters necessary to reproduce published experimental results, reducing the number of parameters from 18 in the full model to eight in the simplified model. We then address the following questions: Is it possible to estimate parameter values for this model using the very limited amount of published experimental data? Furthermore, is it possible to estimate confidence intervals for the determined parameters? The idea that is explored in this paper is based on using bootstrapping. Model parameters were estimated by minimizing the objective function that simulates the discrepancy between the model predictions and experimental data. Residuals were then identified by calculating the differences between the experimental data and model predictions. New, surrogate ‘experimental’ data were generated by randomly resampling residuals. By finding sets of best-fit parameters for a large number of surrogate data the histograms for the model parameters were produced. These histograms were then used to estimate confidence intervals for the model parameters, by using the percentile bootstrap. Once the model was calibrated, we applied it to analysing some features of tau transport that are not accessible to current experimental techniques.}, number={2201}, journal={PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES}, author={Kuznetsov, I. A. and Kuznetsov, A. V.}, year={2017}, month={May} }
@article{jin_kuznetsov_2017, title={Turbulence modeling for flows in wall bounded porous media: An analysis based on direct numerical simulations}, volume={29}, ISSN={["1089-7666"]}, DOI={10.1063/1.4979062}, abstractNote={Various models are available for simulating turbulent flows in porous media. Models based on the eddy viscosity assumption are often adopted to close the Reynolds stress term. In order to validate the assumptions behind such turbulence models, we studied the dynamics of macroscopic momentum and turbulence kinetic energy in porous media flows by utilizing Direct Numerical Simulation (DNS). The generic porous matrix is composed of regularly arranged spheres. The resulting periodic porous medium is bounded by two walls. The DNS analyses with a Lattice Boltzmann method were performed for various values of the applied pressure gradient, pore size to channel width ratio, and porosity. The DNS results were averaged over time and volume to obtain macroscopic results. The results show that the macroscopic shear Reynolds stress in all Representative Elementary Volumes (REVs), independent of their location, is negligibly small, although the mean velocity gradient takes nonzero values near the wall. The turbulence kinetic energy production rate is generally balanced by the dissipation rate in each REV. The DNS results support a zero-equation turbulence model that accounts for the fact that turbulent structures are restricted in size by the pore scale. The DNS results also suggest that the Brinkman term, which expresses the diffusion of momentum, has an important effect near the wall where the gradient of the shear stress is large. Therefore, the Brinkman term should be taken into account in the macroscopic momentum equation as a component of the total drag. A preliminary macroscopic model for calculating turbulent porous media flows has been proposed and compared with our DNS results.}, number={4}, journal={PHYSICS OF FLUIDS}, author={Jin, Y. and Kuznetsov, A. V.}, year={2017}, month={Apr} }
@article{kuznetsov_kuznetsov_2017, title={Using Resampling Residuals for Estimating Confidence Intervals of the Effective Viscosity and Forchheimer Coefficient}, volume={119}, ISSN={["1573-1634"]}, DOI={10.1007/s11242-017-0892-2}, number={2}, journal={TRANSPORT IN POROUS MEDIA}, author={Kuznetsov, I. A. and Kuznetsov, A. V.}, year={2017}, month={Sep}, pages={451–459} }
@article{kuznetsov_kuznetsov_2017, title={Utilization of the bootstrap method for determining confidence intervals of parameters for a model of MAP1B protein transport in axons}, volume={419}, ISSN={["1095-8541"]}, DOI={10.1016/j.jtbi.2017.02.017}, abstractNote={This paper develops a model of axonal transport of MAP1B protein. The problem of determining parameter values for the proposed model utilizing limited available experimental data is addressed. We used a global minimum search algorithm to find parameter values that minimize the discrepancy between model predictions and published experimental results. By analyzing the best fit parameter values it was established that some processes can be dropped from the model without losing accuracy, thus a simplified version of the model was formulated. In particular, our analysis suggests that reversals in MAP1B transport are infrequent and can be neglected. The detachment of anterogradely-biased MAP1B from microtubules (MTs) and the attachment of retrogradely-biased MAP1B to MTs can also be neglected. An analytical solution for the simplified model was obtained. Confidence intervals for the determined parameters were found by bootstrapping model residuals. The resultant analysis heavily constrained the values of some parameters while showing that some could vary without significantly impacting model error. For example, our analysis suggests that, above a certain threshold value, the kinetic constant determining the rate of MAP1B transition from the retrograde pausing state to the off-track state has little impact on model error. On the contrary, the kinetic constant describing MAP1B transition from a pausing to a running state has great impact on model error.}, journal={JOURNAL OF THEORETICAL BIOLOGY}, author={Kuznetsov, I. A. and Kuznetsov, A. V.}, year={2017}, month={Apr}, pages={350–361} }
@article{kuznetsov_kuznetsov_2017, title={What mechanisms of tau protein transport could be responsible for the inverted tau concentration gradient in degenerating axons?}, volume={34}, ISSN={["1477-8602"]}, DOI={10.1093/imammb/dqv041}, abstractNote={In tauopathies, such as Alzheimer's disease (AD), microtubule (MT)-associated protein tau detaches from MTs and aggregates, eventually forming insoluble neurofibrillary tangles. In a healthy axon, the tau concentration increases toward the axon terminal, but in a degenerating axon, the tau concentration gradient is inverted and the highest tau concentration is in the soma. In this article, we developed a mathematical model of tau transport in axons. We calibrated and tested the model by using published distributions of tau concentration and tau average velocity in a healthy axon. According to published research, the inverted tau concentration gradient may be one of the reasons leading to AD. We therefore used the model to investigate what modifications in tau transport can lead to the inverted tau concentration gradient. We investigated whether tau detachment from MTs due to tau hyperphosphorylation can cause the inverted tau concentration gradient. We found that the assumption that most tau molecules are detached from MTs does not consistently predict the inverted tau concentration gradient; the predicted tau distribution becomes more uniform if the axon length is increased. We then hypothesized that in degenerating axons some tau remains bound to MTs and participates in the component 'a' of slow axonal transport but that the rate of tau reversals from anterograde to retrograde motion increases. We demonstrated that this hypothesis results in a tau distribution where the tau concentration has its maximum value at the axon hillock and its minimum value at the axon terminal, in agreement with what is observed in AD. Our results thus suggest that defects in active transport of tau may be a contributing factor to the onset of neural degeneration.}, number={1}, journal={MATHEMATICAL MEDICINE AND BIOLOGY-A JOURNAL OF THE IMA}, author={Kuznetsov, I. A. and Kuznetsov, A. V.}, year={2017}, month={Mar}, pages={125–150} }
@article{uth_jin_kuznetsov_herwig_2016, title={A direct numerical simulation study on the possibility of macroscopic turbulence in porous media: Effects of different solid matrix geometries, solid boundaries, and two porosity scales}, volume={28}, ISSN={["1089-7666"]}, DOI={10.1063/1.4949549}, abstractNote={In this study, we address the question of whether turbulent structures in a porous medium are restricted in size by the pore scale or whether the size of eddies may exceed the pore scale, leading to the formation of macroscopic coherent structures. Based on direct numerical simulations in porous media, we conclude that the size of turbulent eddies is restricted by the pore size, leading to the pore scale prevalence hypothesis (PSPH). We prove this hypothesis by considering four different porous matrices. In particular, we simulated turbulent flow in a two-dimensional matrix, a three-dimensional unbounded matrix, a three-dimensional matrix bounded by two parallel solid walls, and a three-dimensional matrix with two characteristic pore scales. The obtained results for the four simulated porous matrices support the PSPH. However, there is a partly open question of whether turbulent structures can reach the size of the largest pore scale if the solid matrix is characterized by more than one length scale.}, number={6}, journal={PHYSICS OF FLUIDS}, author={Uth, M. -F. and Jin, Y. and Kuznetsov, A. V. and Herwig, H.}, year={2016}, month={Jun} }
@inproceedings{kuznetsov_kuznetsov_2016, title={A model of neuropeptide transport in various types of nerve terminals containing en passant boutons: The effect of the rate of neuropeptide production in the neuron soma}, DOI={10.1115/imece2015-50439}, abstractNote={After being synthesized in the soma, neuropeptides are packaged in dense core vesicles (DCVs) and transported toward nerve terminals. It is known, from published experimental results, that in terminals with type Ib boutons DCVs circulate in the terminal, undergoing repeated anterograde and retrograde transport, while in type III terminals DCVs do not circulate in the terminal. Our goal here is to investigate whether the increased DCV production in the soma can lead to the appearance of DCV circulation in type III boutons. For this purpose we developed a mathematical model that simulates DCV transport in various terminals. Our model reproduces some important experimental results, such as those concerning DCV circulation in type Ib and type III terminals. We used the developed model to make testable predictions. The model predicts that an increased DCV production rate in the soma leads to increased DCV circulation in type Ib boutons and to the appearance of DCV circulation in type III boutons. The model also predicts that there are different stages in the development of DCV circulation in the terminals after they were depleted of DCVs due to neuropeptide release.}, booktitle={Proceedings of the ASME International Mechanical Engineering Congress and Exposition, 2015, vol 3}, author={Kuznetsov, I. A. and Kuznetsov, A. V.}, year={2016} }
@article{kuznetsov_2016, title={Biothermal Convection and Nanofluid Bioconvection}, journal={Handbook of Fluid Dynamics, 2nd Edition}, author={Kuznetsov, A. V.}, year={2016} }
@article{kuznetsov_kuznetsov_2016, title={Can numerical modeling help understand the fate of tau protein in the axon terminal?}, volume={19}, ISSN={1025-5842 1476-8259}, url={http://dx.doi.org/10.1080/10255842.2014.994119}, DOI={10.1080/10255842.2014.994119}, abstractNote={In this paper, we used mathematical modeling to investigate the fate of tau protein in the axon terminal. We developed a comprehensive model of tau transport that accounts for transport of cytosolic tau by diffusion, diffusion transport of microtubule (MT)-bound tau along the MT lattice, active motor-driven transport of MT-bound tau via slow axonal transport mechanism, and degradation of tau in the axon due to tau's finite half-life. We investigated the effect of different assumptions concerning the fate of tau in the terminal on steady-state transport of tau in the axon. In particular, we studied two possible scenarios: (i) tau is destroyed in the terminal and (ii) there is no tau destruction in the terminal, and to avoid tau accumulation we postulated zero flux of tau at the terminal. We found that the tau concentration and percentage of MT-bound tau are not very sensitive to the assumption concerning the fate of tau in the terminal, but the tau's flux and average velocity of tau transport are very sensitive to this assumption. This suggests that measuring the velocity of tau transport and comparing it with the results of mathematical modeling for different assumptions concerning tau's fate in the terminal can provide information concerning what happens to tau in the terminal.}, number={2}, journal={Computer Methods in Biomechanics and Biomedical Engineering}, publisher={Informa UK Limited}, author={Kuznetsov, I.A. and Kuznetsov, A.V.}, year={2016}, month={Jan}, pages={115–125} }
@article{nield_kuznetsov_2016, title={Do Isoflux Boundary Conditions Inhibit Oscillatory Double-Diffusive Convection?}, volume={112}, ISSN={0169-3913 1573-1634}, url={http://dx.doi.org/10.1007/S11242-016-0666-2}, DOI={10.1007/S11242-016-0666-2}, number={3}, journal={Transport in Porous Media}, publisher={Springer Science and Business Media LLC}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2016}, month={Mar}, pages={609–618} }
@article{kuznetsov_kuznetsov_2016, title={Mathematical models of alpha-synuclein transport in axons}, volume={19}, ISSN={["1476-8259"]}, DOI={10.1080/10255842.2015.1043628}, abstractNote={To investigate possible effects of diffusion on α-synuclein (α-syn) transport in axons, we developed two models of α-syn transport, one that assumes that α-syn is transported only by active transport, as part of multiprotein complexes, and a second that assumes an interplay between motor-driven and diffusion-driven α-syn transport. By comparing predictions of the two models, we were able to investigate how diffusion could influence axonal transport of α-syn. The predictions obtained could be useful for future experimental work aimed at elucidating the mechanisms of axonal transport of α-syn. We also attempted to simulate possible defects in α-syn transport early in Parkinson's disease (PD). We assumed that in healthy axons α-syn localizes in the axon terminal while in diseased axons α-syn does not localize in the terminal (this was simulated by postulating a zero α-syn flux into the terminal). We found that our model of a diseased axon predicts the build-up of α-syn close to the axon terminal. This build-up could cause α-syn accumulation in Lewy bodies and the subsequent axonal death pattern observed in PD (‘dying back’ of axons).}, number={5}, journal={COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING}, author={Kuznetsov, I. A. and Kuznetsov, A. V.}, year={2016}, month={Apr}, pages={515–526} }
@article{wu_miao_jasper_kuznetsov_2016, title={Modeling of submicron particle filtration in an electret monolith filter with rectangular cross-section microchannels}, volume={50}, ISSN={["1521-7388"]}, DOI={10.1080/02786826.2016.1218437}, abstractNote={ABSTRACT Electret monolith filters have the advantage of low pressure drop and high filtration efficiency. In such filters, the filtration of submicron aerosol particles occurs as air passes through millions of microchannels. This article investigates the flow and filtration mechanisms in a representative rectangular microchannel of an electret monolith filter. An improved incompressible lattice Boltzmann method with Bhatnagar–Gross–Krook (traditionally shortened as LBGK) and lattice velocity D3Q15 model is employed to simulate no-slip and slip flows in the rectangular microchannels of a monolith filter. We considered mono-disperse submicron particles and one-way coupling (particle motion was affected by the flow, but the presence of particles did not affect the flow). Based on flow computations, the effects of key dimensionless parameters (Reynolds number, Knudsen number, Stokes number and the dimensionless length of the channel) on the total capture efficiency of mono-disperse submicron particles were investigated. Our results indicate that the optimal monolith filter should be characterized by a Knudsen number between 0.022 and 0.044, and that the dimensionless length of the channel should be between 4 and 8. Copyright © 2016 American Association for Aerosol Research}, number={10}, journal={AEROSOL SCIENCE AND TECHNOLOGY}, publisher={Informa UK Limited}, author={Wu, Guojiang and Miao, Zhengqing and Jasper, Warren J. and Kuznetsov, Andrey V.}, year={2016}, pages={1033–1043} }
@article{nield_kuznetsov_2016, title={The Effect of Pulsating Throughflow on the Onset of Convection in a Horizontal Porous Layer}, volume={111}, ISSN={["1573-1634"]}, DOI={10.1007/s11242-015-0622-6}, number={3}, journal={TRANSPORT IN POROUS MEDIA}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2016}, month={Feb}, pages={731–740} }
@article{kuznetsov_nield_2016, title={The Effect of Spatially Nonuniform Internal Heating on the Onset of Convection in a Horizontal Fluid Layer}, volume={138}, ISSN={["1528-8943"]}, DOI={10.1115/1.4032837}, abstractNote={In this paper, we investigated the onset of natural convection in a horizontal fluid layer due to nonuniform internal heat generation, which is relevant to a number of geophysical situations. We investigated a number of special cases, which we believe are paradigmatic. Those include linear, quadratic, concentrated, and exponential source strength distributions. Our results show that those situations that lead to a reduction/increase in the size of the region in which the basic temperature gradient is destabilizing lead to an increase/decrease in stability.}, number={6}, journal={JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME}, author={Kuznetsov, A. V. and Nield, D. A.}, year={2016}, month={Jun} }
@article{nield_kuznetsov_2016, title={The Onset of Convection in a Horizontal Porous Layer with Spatially Non-Uniform Internal Heating}, volume={111}, ISSN={["1573-1634"]}, DOI={10.1007/s11242-015-0610-x}, number={2}, journal={TRANSPORT IN POROUS MEDIA}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2016}, month={Jan}, pages={541–553} }
@article{nield_kuznetsov_barletta_celli_2016, title={The Onset of Convection in a Sloping Layered Porous Medium: Effects of Local Thermal Non-equilibrium and Heterogeneity}, volume={114}, ISSN={["1573-1634"]}, DOI={10.1007/s11242-016-0728-5}, number={1}, journal={TRANSPORT IN POROUS MEDIA}, author={Nield, D. A. and Kuznetsov, A. V. and Barletta, A. and Celli, M.}, year={2016}, month={Aug}, pages={87–97} }
@article{barletta_celli_kuznetsov_nield_2016, title={Unstable Forced Convection in a Plane Porous Channel With Variable-Viscosity Dissipation}, volume={138}, ISSN={["1528-8943"]}, DOI={10.1115/1.4031868}, abstractNote={Fully developed and stationary forced convection in a plane-parallel porous channel is analyzed. The boundary walls are modeled as impermeable and subject to external heat transfer. Different Biot numbers are defined at the two boundary planes. It is shown that the combined effects of temperature-dependent viscosity and viscous heating may induce flow instability. The instability takes place at the lowest parametric singularity of the basic flow solution. The linear stability analysis is carried out analytically for the longitudinal modes and numerically for general oblique modes. It is shown that longitudinal modes with vanishingly small wave number are selected at the onset of instability.}, number={3}, journal={JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME}, author={Barletta, A. and Celli, M. and Kuznetsov, A. V. and Nield, D. A.}, year={2016}, month={Mar} }
@article{kuznetsov_kuznetsov_2016, title={What can trigger the onset of Parkinson's disease - A modeling study based on a compartmental model of alpha-synuclein transport and aggregation in neurons}, volume={278}, ISSN={["1879-3134"]}, DOI={10.1016/j.mbs.2016.05.002}, abstractNote={The aim of this paper is to develop a minimal model describing events leading to the onset of Parkinson's disease (PD). The model accounts for α-synuclein (α-syn) production in the soma, transport toward the synapse, misfolding, and aggregation. The production and aggregation of polymeric α-syn is simulated using a minimalistic 2-step Finke-Watzky model. We utilized the developed model to analyze what changes in a healthy neuron are likely to lead to the onset of α-syn aggregation. We checked the effects of interruption of α-syn transport toward the synapse, entry of misfolded (infectious) α-syn into the somatic and synaptic compartments, increasing the rate of α-syn synthesis in the soma, and failure of α-syn degradation machinery. Our model suggests that failure of α-syn degradation machinery is probably the most likely cause for the onset of α-syn aggregation leading to PD.}, journal={MATHEMATICAL BIOSCIENCES}, author={Kuznetsov, I. A. and Kuznetsov, A. V.}, year={2016}, month={Aug}, pages={22–29} }
@article{kuznetsov_kuznetsov_2015, title={A comparison between the diffusion-reaction and slow axonal transport models for predicting tau distribution along an axon}, volume={32}, ISSN={["1477-8602"]}, DOI={10.1093/imammb/dqu003}, abstractNote={This paper developed equations describing steady-state tau distributions for three versions of the diffusion-reaction model of tau transport: a model with constant kinetic rates, a model that additionally accounts for tau diffusion along microtubules (MTs) and a model with a modulated rate of tau attachment to MTs. We demonstrated that, for the model with constant kinetic rates, the concentration of free tau in the cytoplasm was determined by a single dimensionless parameter that represents the ratio of the diffusion time (the time it takes tau to diffuse from the axon hillock to the axon tip) to the half-life of tau. We also developed a model based on the hypothesis that tau is actively transported. Analytical solutions for some special situations were obtained. The model predictions were compared with experimentally measured tau distributions in axons reported in Black et al. (1996, J. Neurosc., 16: , 3601-3619), and based on these comparisons, we discussed the performance of various models. We demonstrated the significance of modulation of the tau attachment rate to MTs in the diffusion-reaction model. On the other hand, the active transport model predictions were consistent with experimental data even with constant kinetic rates. For short axons (up to 600 μm in length) the predicted average transport velocity of tau was in the experimentally reported range for both the diffusion-reaction and active transport models, but for the active transport model the average tau velocity was larger.}, number={3}, journal={MATHEMATICAL MEDICINE AND BIOLOGY-A JOURNAL OF THE IMA}, author={Kuznetsov, I. A. and Kuznetsov, A. V.}, year={2015}, month={Sep}, pages={263–283} }
@article{kuznetsov_kuznetsov_2015, title={A coupled model of fast axonal transport of organelles and slow axonal transport of tau protein}, volume={18}, ISSN={["1476-8259"]}, DOI={10.1080/10255842.2014.920830}, abstractNote={We have developed a model that accounts for the effect of a non-uniform distribution of tau protein along the axon length on fast axonal transport of intracellular organelles. The tau distribution is simulated by using a slow axonal transport model; the numerically predicted tau distributions along the axon length were validated by comparing them with experimentally measured tau distributions reported in the literature. We then developed a fast axonal transport model for organelles that accounts for the reduction of kinesin attachment rate to microtubules by tau. We investigated organelle transport for two situations: (1) a uniform tau distribution and (2) a non-uniform tau distribution predicted by the slow axonal transport model. We found that non-uniform tau distributions observed in healthy axons (an increase in tau concentration towards the axon tip) result in a significant enhancement of organelle transport towards the synapse compared with the uniform tau distribution with the same average amount of tau. This suggests that tau may play the role of being an enhancer of organelle transport.}, number={13}, journal={COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING}, author={Kuznetsov, I. A. and Kuznetsov, A. V.}, year={2015}, month={Oct}, pages={1485–1494} }
@article{kuznetsov_kuznetsov_2015, title={Can a death signal half-life be used to sense the distance to a lesion site in axons?}, volume={41}, ISSN={["1573-0689"]}, DOI={10.1007/s10867-014-9363-y}, abstractNote={Neuron response to injury depends on the distance to the lesion site, which means that neurons are capable of sensing this distance. Several mechanisms explaining how neurons can do this have been proposed and it is possible that neurons use a combination of several mechanisms to make such measurements. In this paper we investigate the feasibility of the simplest mechanism, which is based on the hypothesis that death signals, produced at the lesion site, propagate toward the neuron soma. The signals are propelled by dynein motors. If signals have a finite half-life, they decay as they propagate. By measuring the concentration of death signals arriving to the soma, neurons should thus be able to determine the distance to the injury site. We develop and solve a transport equation based on the above model. We investigate how a death signal distribution depends on the dynein velocity distribution. We evaluate the efficiency of such a mechanism by investigating the sensitivity of death signal concentration at the soma to the distance to the injury site. By using the hypothesis that system performance is optimized by evolution, we evaluate death signal half-lives that would maximize this sensitivity.}, number={1}, journal={JOURNAL OF BIOLOGICAL PHYSICS}, author={Kuznetsov, I. A. and Kuznetsov, A. V.}, year={2015}, month={Jan}, pages={23–35} }
@article{kuznetsov_kuznetsov_2015, title={Can an increase in neuropeptide production in the soma lead to DCV circulation in axon terminals with type III en passant boutons?}, volume={267}, ISSN={["1879-3134"]}, DOI={10.1016/j.mbs.2015.06.010}, abstractNote={Neuropeptides are synthesized in the neuron soma; they are packaged in dense core vesicles (DCVs) which undergo axonal transport toward nerve terminals. Published experimental results suggest that in terminals with type Ib boutons DCVs circulate in the terminal, undergoing repeated anterograde and retrograde transport, while in type III terminals DCVs do not circulate in the terminal. In this paper we developed a mathematical model that allowed us to investigate the effects of an increased rate of DCV production in the soma. We demonstrated that our model reproduces some important experimental results, in particular those concerning DCV circulation in type Ib and type III terminals. Our model makes testable predictions. Probably the most important prediction concerns the effect of an increased DCV production rate in the soma, which we anticipate leads to increased DCV circulation in type Ib boutons and to the appearance of DCV circulation in type III boutons. Other predictions concern various stages of development of DCV circulation in the terminals after they were depleted of DCVs due to neuropeptide release.}, journal={MATHEMATICAL BIOSCIENCES}, author={Kuznetsov, I. A. and Kuznetsov, A. V.}, year={2015}, month={Sep}, pages={61–78} }
@article{nield_kuznetsov_2015, title={LOCAL THERMAL NON-EQUILIBRIUM AND HETEROGENEITY EFFECTS ON THE ONSET OF CONVECTION IN A LAYERED POROUS MEDIUM WITH VERTICAL THROUGHFLOW}, volume={18}, ISSN={["1934-0508"]}, DOI={10.1615/jpormedia.v18.i2.40}, abstractNote={We investigated the combined effects of throughflow and local thermal non-equilibrium on the onset of convection in a porous medium consisting of two horizontal layers. In our analytical study, which is performed using linear stability theory, we considered variations of permeability, fluid thermal conductivity, solid thermal conductivity, interphase heat transfer coefficient, and porosity. It is found that heterogeneity of permeability and fluid thermal conductivity have a major effect, heterogeneity of the interphase heat transfer coefficient and porosity have a lesser effect, while heterogeneity of solid thermal conductivity is relatively unimportant.}, number={2}, journal={JOURNAL OF POROUS MEDIA}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2015}, pages={125–136} }
@article{kuznetsov_nield_barletta_celli_2015, title={Local Thermal Non-equilibrium and Heterogeneity Effects on the Onset of Double-Diffusive Convection in an Internally Heated and Soluted Porous Medium}, volume={109}, ISSN={["1573-1634"]}, DOI={10.1007/s11242-015-0525-6}, number={2}, journal={TRANSPORT IN POROUS MEDIA}, author={Kuznetsov, A. V. and Nield, D. A. and Barletta, A. and Celli, M.}, year={2015}, month={Sep}, pages={393–409} }
@article{kuznetsov_nield_2015, title={Local thermal non-equilibrium effects on the onset of convection in an internally heated layered porous medium with vertical throughflow}, volume={92}, ISSN={["1778-4166"]}, DOI={10.1016/j.ijthermalsci.2015.01.019}, abstractNote={We investigated how local thermal non-equilibrium and vertical throughflow affect the stability of an internally heated fluid-saturated porous layer. In order to investigate the effects of heterogeneity, we considered a system composed of two horizontal porous layers with different properties. This allowed us to investigate the effects of vertical variation of various parameters. Due to a large number of parameters, our primary goal was to investigate which parameters have a significant effect on the stability of the system. We have found that heterogeneity of permeability and fluid thermal conductivity have a major effect, heterogeneity of interphase heat transfer coefficient and porosity have a lesser effect, while heterogeneity of solid thermal conductivity is relatively unimportant. At the same time we investigated the variation of both upward and downward throughflow, and variation of heat source strength between the layers and between the fluid and solid phases. Downward throughflow is destabilizing, while upward throughflow is stabilizing. The stability is strongly affected by the solid-to-fluid heat source strength ratio.}, journal={INTERNATIONAL JOURNAL OF THERMAL SCIENCES}, author={Kuznetsov, A. V. and Nield, D. A.}, year={2015}, month={Jun}, pages={97–105} }
@article{kuznetsov_kuznetsov_2015, title={Modeling neuropeptide transport in various types of nerve terminals containing en passant boutons}, volume={261}, ISSN={["1879-3134"]}, DOI={10.1016/j.mbs.2014.12.001}, abstractNote={We developed a mathematical model for simulating neuropeptide transport inside dense core vesicles (DCVs) in axon terminals containing en passant boutons. The motivation for this research is a recent experimental study by Levitan and colleagues (Bulgari et al., 2014) which described DCV transport in nerve terminals of type Ib and type III as well as in nerve terminals of type Ib with the transcription factor DIMM. The goal of our modeling is validating the proposition put forward by Levitan and colleagues that the dramatic difference in DCV number in type Ib and type III terminals can be explained by the difference in DCV capture in type Ib and type III boutons rather than by differences in DCV anterograde transport and half-life of resident DCVs. The developed model provides a tool for studying the dynamics of DCV transport in various types of nerve terminals. The model is also an important step in gaining a better mechanistic understanding of transport processes in axons and identifying directions for the development of new models in this area.}, journal={MATHEMATICAL BIOSCIENCES}, author={Kuznetsov, I. A. and Kuznetsov, A. V.}, year={2015}, month={Mar}, pages={27–36} }
@article{kuznetsov_kuznetsov_2015, title={Modelling organelle transport after traumatic axonal injury}, volume={18}, ISSN={["1476-8259"]}, DOI={10.1080/10255842.2013.820721}, abstractNote={This paper is motivated by recent experimental research (Tang-Schomer et al. 2012) on the formation of periodic varicosities in axons after traumatic brain injury (TBI). TBI leads to the formation of undulated distortions in the axons due to their dynamic deformation. These distortions result in the breakage of some microtubules (MTs) near the peaks of undulations. The breakage is followed by catastrophic MT depolymerisation around the broken ends. Although after relaxation axons regain their straight geometry, the structure of the axon after TBI is characterised by the presence of periodic regions where the density of MTs has been decreased due to depolymerisation. We modelled organelle transport in an axon segment with such a damaged MT structure and investigated how this structure affects the distributions of organelle concentrations and fluxes. The modelling results suggest that organelles accumulate at the boundaries of the region where the density of MTs has been decreased by depolymerisation. According to the model, the presence of such damaged regions decreases the organelle flux by only about 12%. This provides evidence that axon degradation after TBI may be caused by organelle accumulation rather than by starvation due to insufficient organelle flux.}, number={6}, journal={COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING}, author={Kuznetsov, I. A. and Kuznetsov, A. V.}, year={2015}, month={Apr}, pages={583–591} }
@article{jin_uth_kuznetsov_herwig_2015, title={Numerical investigation of the possibility of macroscopic turbulence in porous media: a direct numerical simulation study}, volume={766}, ISSN={["1469-7645"]}, DOI={10.1017/jfm.2015.9}, abstractNote={Abstract}, journal={JOURNAL OF FLUID MECHANICS}, author={Jin, Y. and Uth, M. -F. and Kuznetsov, A. V. and Herwig, H.}, year={2015}, month={Mar}, pages={76–103} }
@article{nield_kuznetsov_2015, title={The Effect of Vertical Throughflow on Thermal Instability in a Porous Medium Layer Saturated by a Nanofluid: A Revised Model}, volume={137}, ISSN={["1528-8943"]}, DOI={10.1115/1.4029773}, abstractNote={The model developed in our previous paper (Nield and Kuznetsov, 2011, “The Effect of Vertical Throughflow on Thermal Instability in a Porous Medium Layer Saturated by a Nanofluid,” Transp. Porous Media, 87(3), pp. 765–775) is now revised to accommodate a more realistic boundary condition on the nanoparticle volume fraction. The new boundary condition postulates zero nanoparticle flux through the boundaries. We established that in the new model, oscillatory instability is impossible. We also established that the critical Rayleigh number depends on three dimensionless parameters, and we derived these three parameters from the governing equations. We also briefly investigated the major trends.}, number={5}, journal={JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2015}, month={May} }
@article{nield_kuznetsov_barletta_celli_2015, title={The Effects of Double Diffusion and Local Thermal Non-equilibrium on the Onset of Convection in a Layered Porous Medium: Non-oscillatory Instability}, volume={107}, ISSN={["1573-1634"]}, DOI={10.1007/s11242-014-0436-y}, number={1}, journal={TRANSPORT IN POROUS MEDIA}, author={Nield, D. A. and Kuznetsov, A. V. and Barletta, A. and Celli, M.}, year={2015}, month={Mar}, pages={261–279} }
@inproceedings{herwig_jin_uth_kuznetsov_2015, title={Turbulent flow in the micro structures of porous media}, DOI={10.1115/icnmm2015-48074}, abstractNote={Some fundamental issues with respect to turbulent flows through a porous matrix are addressed by analyzing DNS results (DNS: direct numerical simulation, i.e. no turbulence modeling). In a porous matrix with pore sizes of micro or even nano dimensions turbulent flow may occur when the (local) Reynolds number is sufficiently large. An open question, however, is whether turbulence structures are restricted in size by the pore size dimensions or not. This is an important aspect that immediately affects the way turbulence has to be modelled. In order to find out which influence the solid matrix has on the turbulence a generic matrix built from a large number of bars with square cross sections is investigated. Two different DNS approaches are used, a finite volume one and a Lattice-Boltzmann approach. From both DNS calculations detailed flow field information about the influence of the solid matrix on the turbulence structure are obtained. Finally the extension of Darcy’s friction law by the Forchheimer term is investigated with respect to the question whether this extended law may be used in the fully turbulent flow regime.}, booktitle={Proceedings of the ASME 13th International Conference on Nanochannels, Microchannels, and Minichannels, 2015}, author={Herwig, H. and Jin, Y. and Uth, M. F. and Kuznetsov, A. V.}, year={2015} }
@article{kuznetsov_kuznetsov_2014, title={A two population model of prion transport through a tunnelling nanotube}, volume={17}, ISSN={["1476-8259"]}, DOI={10.1080/10255842.2013.763938}, abstractNote={This article develops a two prion population model that simulates prion trafficking between an infected dendritic cell and a neuron. The situation when the two cells are connected by a tunnelling nanotube (TNT) is simulated. Two mechanisms of prion transport are considered: lateral diffusion in the TNT membrane and active actin-dependent transport inside endocytic vesicles that are propelled by myosin Va molecular motors. Analytical solutions describing prion concentrations and fluxes are obtained. Numerical results are compared with those predicted by a single prion population model that relies on a single reaction–diffusion equation and accounts for the two modes of prion transport in an effective way.}, number={15}, journal={COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING}, author={Kuznetsov, I. A. and Kuznetsov, A. V.}, year={2014}, pages={1705–1715} }
@article{kuznetsov_blinov_avramenko_shevchuk_tyrinov_kuznetsov_2014, title={Approximate modelling of the leftward flow and morphogen transport in the embryonic node by specifying vorticity at the ciliated surface}, volume={738}, ISSN={["1469-7645"]}, DOI={10.1017/jfm.2013.588}, abstractNote={Abstract}, journal={JOURNAL OF FLUID MECHANICS}, author={Kuznetsov, A. V. and Blinov, D. G. and Avramenko, A. A. and Shevchuk, I. V. and Tyrinov, A. I. and Kuznetsov, I. A.}, year={2014}, month={Jan}, pages={492–521} }
@article{mironov_kuznetsov_emel’yanov_2014, title={Consideration of Cyclic Degradation of the Material and Abnormality of the Surface Layer Mechanical Properties in Calculating the Life of a Plate with an Opening*}, volume={46}, ISSN={0039-2316 1573-9325}, url={http://dx.doi.org/10.1007/S11223-014-9594-Y}, DOI={10.1007/S11223-014-9594-Y}, number={5}, journal={Strength of Materials}, publisher={Springer Science and Business Media LLC}, author={Mironov, V. I. and Kuznetsov, A. V. and Emel’yanov, I. G.}, year={2014}, month={Sep}, pages={638–643} }
@article{barletta_celli_kuznetsov_2014, title={Convective Instability of the Darcy Flow in a Horizontal Layer With Symmetric Wall Heat Fluxes and Local Thermal Nonequilibrium}, volume={136}, ISSN={["1528-8943"]}, DOI={10.1115/1.4024070}, abstractNote={The linear stability of the parallel Darcy throughflow in a horizontal plane porous layer with impermeable boundaries subject to a symmetric net heating or cooling is investigated. The onset conditions for the secondary thermoconvective flow are expressed through a neutral stability bound for the Darcy–Rayleigh number associated with the uniform heat flux supplied or removed from the walls. The study is performed by taking into account a condition of local thermal nonequilibrium between the solid phase and the fluid phase. The linear stability analysis is carried out according to the normal modes' decomposition of the perturbations to the basic state. The governing equations for the disturbances are solved numerically as an eigenvalue problem leading to the neutral stability condition. If compared with the asymptotic condition of local thermal equilibrium, the regime of local nonequilibrium manifests an enhanced instability. This behavior is displayed by lower critical values of the Darcy–Rayleigh number, eventually tending to zero when the thermal conductivity of the solid phase is much larger than the conductivity of the fluid phase. In this special limit, which can be invoked as an approximate model of a gas-saturated metallic foam, the basic throughflow is always unstable to external disturbances of arbitrarily small amplitude.}, number={1}, journal={JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME}, author={Barletta, A. and Celli, M. and Kuznetsov, A. V.}, year={2014}, month={Jan} }
@article{nield_kuznetsov_2014, title={Forced convection in a parallel-plate channel occupied by a nanofluid or a porous medium saturated by a nanofluid}, volume={70}, ISSN={["1879-2189"]}, DOI={10.1016/j.ijheatmasstransfer.2013.11.016}, abstractNote={An analytical study is made of fully-developed laminar forced convection in a parallel-plate channel occupied by a nanofluid or by a porous medium saturated by a nanofluid, subject to uniform-flux boundary conditions. A model incorporating the effects of Brownian motion and thermophoresis is adopted. (Previous analytical studies using this model have been concerned with natural convection.) It is found that the combined effect of these two agencies is to reduce the Nusselt number.}, journal={INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2014}, month={Mar}, pages={430–433} }
@article{nield_kuznetsov_2014, title={Forced convection in a parallel-plate channel occupied by a nanofluid or a porous medium saturated by a nanofluid (vol 70, pg 430, 2014)}, volume={76}, ISSN={["1879-2189"]}, DOI={10.1016/j.ijheatmasstransfer.2014.04.051}, journal={INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2014}, month={Sep}, pages={534–534} }
@article{nield_kuznetsov_2014, title={Local Thermal Non-Equilibrium and Heterogeneity Effects on the Onset of Convection in a Layered Porous Medium}, volume={102}, ISSN={["1573-1634"]}, DOI={10.1007/s11242-013-0224-0}, number={1}, journal={TRANSPORT IN POROUS MEDIA}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2014}, month={Mar}, pages={1–13} }
@article{kuznetsov_nield_2014, title={Local Thermal Non-equilibrium and Heterogeneity Effects on the Onset of Convection in an Internally Heated Porous Medium}, volume={102}, ISSN={["1573-1634"]}, DOI={10.1007/s11242-013-0258-3}, number={1}, journal={TRANSPORT IN POROUS MEDIA}, author={Kuznetsov, A. V. and Nield, D. A.}, year={2014}, month={Mar}, pages={15–30} }
@article{kuznetsov_kuznetsov_2014, title={Modeling anterograde and retrograde transport of short mobile microtubules from the site of axonal branch formation}, volume={40}, ISSN={["1573-0689"]}, DOI={10.1007/s10867-013-9334-8}, abstractNote={This theoretical research is motivated by a recent model of microtubule (MT) transport put forward by Baas and Mozgova (Cytoskeleton 69:416-425, 2012). According to their model, in an axon all plus-end-distal mobile MTs move anterogradely while all minus-end-distal mobile MTs move retrogradely. Retrograde MT transport thus represents a mechanism by which minus-end-distal MTs are removed from the axon. We suggested equations that implement Baas and Mozgova's model. We employed these equations to simulate transport of short mobile MTs from a region (such as the site of axonal branch formation) where MT severing activity results in generation of a large number of short MTs of both orientations. We obtained the exact and approximate transient solutions of these equations utilizing the Laplace transform technique. We applied the obtained solutions to calculate the average rates of anterograde and retrograde transport of short MTs.}, number={1}, journal={JOURNAL OF BIOLOGICAL PHYSICS}, author={Kuznetsov, I. A. and Kuznetsov, A. V.}, year={2014}, month={Jan}, pages={41–53} }
@inproceedings{kuznetsov_blinov_avramenko_shevchuk_tyrinov_kuznetsov_2014, title={Modeling leftward flow in the embryonic node}, DOI={10.1115/imece2013-62503}, abstractNote={The establishment of the left-right asymmetry during the development of vertebrates is a fascinating phenomenon that is still not fully understood. Extensive research suggests that in mice a small triangular cavity, called the ventral node, is responsible for breaking the left-right symmetry. A mouse node is ∼ 50 microns across and ∼10 microns deep. The surface of the nodal pit is covered by 200–300 monocilia whose rotation is responsible for the leftward flow in the node. We developed a simplified method of modeling the extraembryonic fluid flow and morphogen transport in a nodal cavity. We simplified the problem as flow in a 2D cavity; the effect of rotating cilia was modeled by specifying a constant vorticity at the edge of the ciliated layer. We also developed approximate solutions for morphogen transport in the nodal pit. The solutions were obtained utilizing the proper generalized decomposition method. We compared our approximate solutions with the results of numerical simulation of flow caused by the rotation of 81 cilia, and obtained reasonable agreement in most of the flow domain. We discuss locations where agreement is less accurate. The obtained semi-analytical solutions enable a quick analysis of flow and morphogen distribution in a nodal pit.}, booktitle={Proceedings of the ASME International Mechanical Engineering Congress and Exposition, 2013, vol 7B}, author={Kuznetsov, A. V. and Blinov, D. G. and Avramenko, A. A. and Shevchuk, I. V. and Tyrinov, A. I. and Kuznetsov, I. A.}, year={2014} }
@inproceedings{kuznetsov_kuznetsov_2014, title={Modeling of tau protein transport in axons}, DOI={10.1115/imece2013-62430}, abstractNote={This paper develops a simplified analytical solution for the slow axonal transport of tau proteins. A six kinetic state model developed in Jung and Brown [1] was used to simulate transport of tau. The model was extended by accounting for tau degradation and diffusion in the off-track kinetic states. The analytical solution was obtained by assuming that transitions between anterograde and retrograde states are infrequent. This assumption was validated through an analysis of the sensitivity of the solution to changes in the values of the two kinetic constants that describe the transition rates between the anterograde and retrograde states, and by a comparison with the experimentally measured tau distributions reported in Konzack et al. [2]. The predicted average transport velocity of tau was also in the experimentally reported range.}, booktitle={Proceedings of the ASME International Mechanical Engineering Congress and Exposition, 2013, vol 3B}, author={Kuznetsov, I. A. and Kuznetsov, A. V.}, year={2014} }
@inproceedings{kuznetsov_kuznetsov_2014, title={Modeling prion transport in a tunneling nanotube}, DOI={10.1115/imece2013-62461}, abstractNote={We develop a model for simulating prion transport in a tunneling nanotube (TNT). We simulate the situation when two cells, one of which is infected, are connected by a TNT. We consider two mechanisms of prion transport: lateral diffusion in the TNT membrane and active actin-dependent transport inside endocytic vesicles. Endocytic vesicles are propelled by myosin Va molecular motors. Since the transit time of prions through a TNT is short (several minutes), the two population model developed here assumes that there is no interchange between the two prion populations, and that partitioning between the prion populations is decided by prion loading at the TNT entrance. The split between the two prion populations at the TNT entrance is decided by the degree of loading, which indicates the portion of prions that enter a TNT in endocytic vesicles. An analytical solution describing prion concentrations and fluxes is obtained.}, booktitle={Proceedings of the ASME International Mechanical Engineering Congress and Exposition, 2013, vol 3B}, author={Kuznetsov, I. A. and Kuznetsov, A. V.}, year={2014} }
@article{kuznetsov_nield_2014, title={Natural convective boundary-layer flow of a nanofluid past a vertical plate: A revised model}, volume={77}, ISSN={["1778-4166"]}, DOI={10.1016/j.ijthermalsci.2013.10.007}, abstractNote={The problem of natural convective boundary-layer flow of a nanofluid past a vertical plate is revisited. The model, which includes the effects of Brownian motion and thermophoresis, is revised so that the nanofluid particle fraction on the boundary is passively rather than actively controlled. In this respect the model is more realistic physically than that employed by previous authors.}, journal={INTERNATIONAL JOURNAL OF THERMAL SCIENCES}, author={Kuznetsov, A. V. and Nield, D. A.}, year={2014}, month={Mar}, pages={126–129} }
@article{kuznetsov_2014, title={Sorting of cargos between axons and dendrites: modelling of differences in cargo transport in these two types of neurites}, volume={17}, ISSN={["1476-8259"]}, DOI={10.1080/10255842.2012.716047}, abstractNote={Explaining how intracellular cargos are sorted between axons and dendrites is important for a mechanistic understanding of what happens in many neurodegenerative disorders. A simple model of cargo sorting relies on differences in microtubule (MT) orientation between axons and dendrites: in mammalian neurons all MTs in axons have their plus ends directed outward while in proximal regions of dendrites the MT polarity is mixed. It can therefore be assumed that cargos that need to be driven into axons associate with kinesin motors while cargos that need to be driven into dendrites associate with dynein motors. This paper develops equations of cargo transport in axons and dendrites based on the above assumptions. Propagation of a pulse of radiolabelled cargos entering an axon and dendrite is simulated. The model equations are solved utilising the Laplace transform method. Differences in cargo transport between axons and dendrites are discussed.}, number={7}, journal={COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING}, author={Kuznetsov, A. V.}, year={2014}, month={May}, pages={792–799} }
@article{nield_kuznetsov_2014, title={The Onset of Convection in an Internally Heated Nanofluid Layer}, volume={136}, ISSN={["1528-8943"]}, DOI={10.1115/1.4025048}, abstractNote={We analytically studied the onset of convection, induced by internal heating, such as that produced by microwave heating or chemical reaction, in a horizontal layer of a nanofluid subject to Brownian motion and thermophoresis. This is a fundamentally different situation from traditionally studied heating from below. Convection, when it occurs, is now concentrated in the portion of the layer where the upward vertical gradient is negative, which is the upper portion of the layer. The situation of internal heating also allows employing more realistic boundary conditions than those hitherto used.}, number={1}, journal={JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2014}, month={Jan} }
@article{nield_kuznetsov_2014, title={The onset of convection in a horizontal nanofluid layer of finite depth: A revised model}, volume={77}, ISSN={["1879-2189"]}, DOI={10.1016/j.ijheatmasstransfer.2014.06.020}, abstractNote={This paper presents a revised linear stability analysis for the onset of natural convection in a horizontal nanofluid layer. The employed model incorporates the effects of Brownian motion and thermophoresis. It is now assumed that the value of the temperature can be imposed on the boundaries, but the nanoparticle fraction adjusts so that the nanoparticle flux is zero on the boundaries. It is shown that, with the new boundary conditions, oscillatory convection can no longer occur. The pertinent dimensionless nanofluid parameters have been rescaled. The effect of the nanoparticles on non-oscillatory convection is destabilizing.}, journal={INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2014}, month={Oct}, pages={915–918} }
@article{nield_kuznetsov_2014, title={Thermal instability in a porous medium layer saturated by a nanofluid: A revised model}, volume={68}, ISSN={["1879-2189"]}, DOI={10.1016/j.ijheatmasstransfer.2013.09.026}, abstractNote={We develop an extension of our previous thermal instability analysis of a nanofluid-saturated porous layer. The extension is based on a new boundary condition for the nanoparticle fraction, which is physically more realistic. In the previous model we imposed both temperature and nanoparticle volume fractions at the boundaries of the layer. It is now assumed that the value of the temperature can be imposed on the boundaries, but the nanoparticle fraction adjusts so that the nanoparticle flux is zero on the boundaries. The new boundary condition on the nanoparticle volume fraction is made possible by accounting for the contributions of the effect of thermophoresis to the nanoparticle flux. It is shown that, with the new boundary conditions, oscillatory convection cannot occur. The effect of the nanoparticles on non-oscillatory convection is destabilizing.}, journal={INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2014}, month={Jan}, pages={211–214} }
@article{kuznetsov_kuznetsov_2014, title={What tau distribution maximizes fast axonal transport toward the axonal synapse?}, volume={253}, ISSN={["1879-3134"]}, DOI={10.1016/j.mbs.2014.04.001}, abstractNote={This theoretical research is aimed at investigating the question of why tau protein concentration exhibits a proximal–distal increase in healthy axons and a proximal–distal decrease in degenerating axons in Alzheimer’s disease. We developed a model of fast axonal transport toward the axon synapse. The model is based on recently published experimental results by Dixit et al. (2008) [1] who reported that the attachment rate of kinesin-1 to MTs is reduced by tau. Cytoplasmic dynein is affected less by tau (dynein is affected at much higher tau concentrations than those that affect kinesin-1). We used the model to investigate the effect of various tau distributions along the axon length on organelle flux toward the axon synapse. We found that a proximal–distal increase in tau concentration leads to a higher organelle flux while a proximal–distal decrease in tau concentration leads to a smaller organelle flux than a uniform tau concentration. We also computed what tau distribution would give the largest organelle flux toward the synapse. We found that in order to maximize organelle flux, the tau concentration has to be at its minimum level in the proximal axon and its maximum level at the distal axon, which is in agreement with the bang–bang principle in optimal control theory.}, journal={MATHEMATICAL BIOSCIENCES}, author={Kuznetsov, I. A. and Kuznetsov, A. V.}, year={2014}, month={Jul}, pages={19–24} }
@article{kuznetsov_kuznetsov_2013, title={A compartmental model of neuropeptide circulation and capture between the axon soma and nerve terminals}, volume={29}, ISSN={["2040-7939"]}, DOI={10.1002/cnm.2542}, abstractNote={SUMMARY}, number={5}, journal={INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING}, author={Kuznetsov, I. A. and Kuznetsov, A. V.}, year={2013}, month={May}, pages={574–585} }
@article{nield_kuznetsov_2013, title={A note on modeling high speed flow in a bidisperse porous medium}, volume={96}, DOI={10.1007/s11242-012-0102-1}, number={3}, journal={Transport in Porous Media}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2013}, pages={495–499} }
@article{nield_kuznetsov_2013, title={A note on the variation of nanofluid viscosity with temperature}, volume={41}, ISSN={["0735-1933"]}, DOI={10.1016/j.icheatmasstransfer.2012.11.001}, abstractNote={Abstract The variation with temperature of the effective viscosity of a nanofluid, together with the effect of particle size on this quantity, is discussed. The analysis of available experimental correlations suggests that the effect of the particle size is approximately independent of the temperature, and increases the viscosity by an amount that decreases with the increase of size. Physically, we expect that this happens because increased size means fewer particles per unit volume, which results in decreased interference with the rate at which fluid molecules reorganise themselves in groups.}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2013}, month={Feb}, pages={17–18} }
@article{nield_kuznetsov_2013, title={An Historical and Topical Note on Convection in Porous Media}, volume={135}, ISSN={["1528-8943"]}, DOI={10.1115/1.4023567}, abstractNote={This note deals with three main themes. The first is a discussion of the early literature on convection in porous media. The second is a brief overview of current analytical modeling of single-phase convection in saturated porous media and in composite fluid/porous-medium domains. The third is a brief discussion of some pertinent recent studies involving nanofluids, cellular porous materials, bidisperse and tridisperse porous media.}, number={6}, journal={JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2013}, month={Jun} }
@article{kuznetsov_2013, title={An analytical solution describing the propagation of positive injury signals in an axon: effect of dynein velocity distribution}, volume={16}, ISSN={["1025-5842"]}, DOI={10.1080/10255842.2011.632376}, abstractNote={A model describing the propagation of positive injury signals from the lesion site in an axon towards the neuron soma is described. It is assumed that these signals are driven by dynein molecular motors. An analytical solution that accounts for the probability density function (pdf) of a dynein velocity distribution is obtained. Two examples of pdf of dynein velocity distributions that follow from the results published in Ross et al. (2006, Processive bidirectional motion of dynein–dynactin complexes in vitro. Nat Cell Biol. 8:562–570) and Deinhardt et al. (2006, Rab5 and Rab7 control endocytic sorting along the axonal retrograde transport pathway. Neuron 52:293–305) are considered. The effect of dynein velocity distribution on the rate of spreading of the signal wave is discussed. It is demonstrated that the obtained solution can be applied to the problem of how neurons measure the distance between the lesion site and the neuron soma.}, number={7}, journal={COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING}, author={Kuznetsov, A. V.}, year={2013}, month={Jul}, pages={699–706} }
@article{kuznetsov_2013, title={An exact solution of transient equations describing slow axonal transport}, volume={16}, ISSN={["1476-8259"]}, DOI={10.1080/10255842.2012.662679}, abstractNote={An exact analytical solution of equations describing slow axonal transport of cytoskeletal elements (CEs) injected in an axon is presented. The equations modelling slow axonal transport are based on the stop-and-go hypothesis. The simplest model implementing this hypothesis postulates that CEs switch between pausing and running kinetic states, and that the probabilities of CE transition between these two states are described by first-order rate constants. It is assumed that initially CEs are injected such that they form a uniform pulse of a given width. All injected CEs are initially attributed to the pausing state. It is shown that within 30 s kinetic processes redistribute CEs between pausing and running states; after that the process occurs under quasi-equilibrium conditions. The parameter accessible to experiments is the total concentration of CEs (pausing plus running). As the initial rectangular-shaped pulse moves, it changes its shape to become a bell-shaped wave that spreads out as it propagates. The wave's amplitude is decreasing during the wave's propagation. It is also shown that the system forgets its initial condition, meaning that if one starts with pulses of different widths, after sometime they converge to the same bell-shaped wave.}, number={11}, journal={COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING}, author={Kuznetsov, A. V.}, year={2013}, month={Nov}, pages={1232–1239} }
@article{kuznetsov_kuznetsov_2013, title={Analytical comparison between Nixon-Logvinenko's and Jung-Brown's theories of slow neurofilament transport in axons}, volume={245}, ISSN={["1879-3134"]}, DOI={10.1016/j.mbs.2013.08.001}, abstractNote={This paper develops analytical solutions describing slow neurofilament (NF) transport in axons. The obtained solutions are based on two theories of NF transport: Nixon–Logvinenko’s theory that postulates that most NFs are incorporated into a stationary cross-linked network and only a small pool is slowly transported and Jung–Brown’s theory that postulates a single dynamic pool of NFs that are transported according to the stop-and-go hypothesis. The simplest two-kinetic state version of the model developed by Jung and Brown was compared with the theory developed by Nixon and Logvinenko. The model for Nixon–Logvinenko’s theory included stationary, pausing, and running NF populations while the model used for Jung–Brown’s theory only included pausing and running NF populations. Distributions of NF concentrations resulting from Nixon–Logvinenko’s and Jung-Brown’s theories were compared. In previous publications, Brown and colleagues successfully incorporated slowing of NF transport into their model by assuming that some kinetic constants depend on the distance from the axon hillock. In this paper we defined the average rate of NF transport as the rate of motion of the center of mass of radiolabeled NFs. We have shown that for this definition, if all kinetic rates are assumed constant, Jung–Brown’s theory predicts a constant average rate of NF transport. We also demonstrated that Nixon–Logvinenko’s theory predicts slowing of NF transport even if all kinetic rates are assumed constant, and the obtained slowing agrees well with published experimental data.}, number={2}, journal={MATHEMATICAL BIOSCIENCES}, author={Kuznetsov, I. A. and Kuznetsov, A. V.}, year={2013}, month={Oct}, pages={331–339} }
@article{kuznetsov_2013, title={Analytical modelling of retrograde transport of nerve growth factors in an axon: a transient problem}, volume={16}, ISSN={["1025-5842"]}, DOI={10.1080/10255842.2011.607445}, abstractNote={The purpose of this paper was to develop an analytical solution describing retrograde transport of nerve growth factors (NGFs) from a target tissue to the neuron soma. The obtained solution is applied to describe two situations: (1) when all dynein motors are moving at a constant velocity and (2) when the dynein velocity distribution is described by a probability density function. The dynamics of NGF concentrations and fluxes is investigated. It is established that the magnitude of the diffusion flux forms a wave localised in space and propagating towards the neuron soma; the magnitude of this wave decreases as the wave propagates downstream. The dynein-driven flux of NGFs is demonstrated to be the main component in the NGF flux, which is shown to be strongly correlated with the NGF concentration.}, number={1}, journal={COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING}, author={Kuznetsov, A. V.}, year={2013}, month={Jan}, pages={95–102} }
@article{nield_kuznetsov_simmons_2013, title={Deep Saline Fluids in Geologic Basins: The Possible Role of the Soret Effect}, volume={99}, ISSN={["0169-3913"]}, DOI={10.1007/s11242-013-0186-2}, number={2}, journal={TRANSPORT IN POROUS MEDIA}, author={Nield, D. A. and Kuznetsov, A. V. and Simmons, Craig T.}, year={2013}, month={Sep}, pages={297–305} }
@article{nield_kuznetsov_2013, title={Forced Convection Past a Rotating Sphere: Modeling Oxygen Transport to a Pond Snail Embryo}, volume={135}, ISSN={["1528-8943"]}, DOI={10.1115/1.4024871}, abstractNote={Helisoma trivolvis pond snail embryos are known for their rotation, which is induced by beating of cilia at the embryo's surface. A common hypothesis links this behavior to enhancing oxygen transfer to the embryo's surface. In this paper, this hypothesis is quantified, and the effect of the rotation on the supply of oxygen to an embryo, which is approximately spherical in shape, is studied. To the best of our knowledge, this is the first research presenting a quantitative study on the effect of an embryo's rotation on facilitating gaseous exchange between the embryo and the environment.}, number={12}, journal={JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2013}, month={Dec} }
@article{gangadharan_sanghavi_kuznetsov_jasper_2013, title={Modeling of Flow Through a Sandwiched Monolith Filter}, volume={31}, ISSN={["0272-6351"]}, DOI={10.1080/02726351.2012.715614}, abstractNote={The flow field and filtration efficiency was modeled and analyzed for a novel monolith filter, comprised of a series of layers of microchannels. In our simulations, we considered two scenarios: the fluid flowing tangentially across the filter face (cross flow) and fluid flowing normal to the filter face (normal flow). The aim of this article is to study the effect of having two or more layers of filters in series on particle capture efficiency. This will help in understanding the mechanisms of particle capture and provide inputs for studying particle segregation or selective filtration using monolith filters. The influences of particle size, number of filter layers and pressure drop on particle capture efficiency were also investigated.}, number={3}, journal={PARTICULATE SCIENCE AND TECHNOLOGY}, publisher={Informa UK Limited}, author={Gangadharan, S. and Sanghavi, R. S. and Kuznetsov, A. V. and Jasper, W. J.}, year={2013}, month={May}, pages={226–233} }
@article{kuznetsov_2013, title={Modeling transport of a pulse of radiolabeled organelles in a Drosophila unipolar motor neuron}, volume={39}, ISSN={["1573-0689"]}, DOI={10.1007/s10867-012-9292-6}, abstractNote={Based on published experimental evidence, this paper develops a model for the transport of a pulse of radiolabeled organelles in a unipolar Drosophila motor neuron. In particular, since published data indicate that no microtubules (MTs) travel from the primary neurite into the dendrite, it is investigated how organelles are transported into the dendrite. Analytical solutions describing concentrations of kinesin- and dynein-driven organelles in the primary neurite, axon, and dendrite are obtained. The effects of increasing the width of the pulse and increasing the rate of organelle transition rate from the kinesin-driven to the dynein-driven state are investigated.}, number={1}, journal={JOURNAL OF BIOLOGICAL PHYSICS}, author={Kuznetsov, A. V.}, year={2013}, month={Jan}, pages={145–158} }
@article{kuznetsov_2013, title={Modelling of axonal cargo rerouting in a dendrite}, volume={30}, ISSN={["1477-8602"]}, DOI={10.1093/imammb/dqs021}, abstractNote={This paper develops a model of axonal cargo transport in and out of a dendrite en route to the axon. The entrance of axonal cargos into a dendrite is explained by a mixed orientation of microtubules (MTs) in a dendrite. Using the simplest hypothesis explaining cargo targeting to axons and dendrites (this hypothesis postulates that axonal cargos are driven by kinesin motors and that dendritic cargos are driven by dynein motors), it is assumed that axonal cargos can enter a dendrite using MTs whose plus-ends are directed outward. Later, as kinesin motors detach from these MTs and reattach to oppositely directed MTs, the axonal cargos are transported out of the dendrite and are rerouted to the axon. The developed model makes it possible to investigate the dynamics of axonal cargo trafficking in a dendrite and study how it is affected by various input parameters, such as the kinesin velocity distribution.}, number={3}, journal={MATHEMATICAL MEDICINE AND BIOLOGY-A JOURNAL OF THE IMA}, author={Kuznetsov, A. V.}, year={2013}, month={Sep}, pages={273–285} }
@article{kuznetsov_2013, title={Numerical investigation of axonal cargo rerouting in a dendrite: A three kinetic state model}, volume={29}, ISSN={["2040-7947"]}, DOI={10.1002/cnm.2521}, abstractNote={SUMMARY}, number={3}, journal={INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING}, author={Kuznetsov, A. V.}, year={2013}, month={Mar}, pages={428–443} }
@article{nield_kuznetsov_2013, title={Onset of Convection with Internal Heating in a Porous Medium Saturated by a Nanofluid}, volume={99}, ISSN={["1573-1634"]}, DOI={10.1007/s11242-013-0174-6}, number={1}, journal={TRANSPORT IN POROUS MEDIA}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2013}, month={Aug}, pages={73–83} }
@article{nield_kuznetsov_2013, title={Onset of Convection with Internal Heating in a Weakly Heterogeneous Porous Medium}, volume={98}, ISSN={["1573-1634"]}, DOI={10.1007/s11242-013-0158-6}, number={3}, journal={TRANSPORT IN POROUS MEDIA}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2013}, month={Jul}, pages={543–552} }
@article{nield_kuznetsov_2013, title={Optimization of Forced Convection Heat Transfer in a Composite Porous Medium Channel}, volume={99}, ISSN={["1573-1634"]}, DOI={10.1007/s11242-013-0189-z}, number={2}, journal={TRANSPORT IN POROUS MEDIA}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2013}, month={Sep}, pages={349–357} }
@article{kuznetsov_2013, title={Protein transport in the connecting cilium of a photoreceptor cell: Modeling the effects of bidirectional protein transitions between the diffusion-driven and motor-driven kinetic states}, volume={43}, ISSN={["1879-0534"]}, DOI={10.1016/j.compbiomed.2013.03.009}, abstractNote={Physics of protein transport through the connecting cilium (CC) of a photoreceptor cell is a long-standing question in cellular biology. There is evidence implicating both molecular motor-driven and diffusion-driven modes of intracellular transport. Based on available experimental clues, this paper develops a new model for intraflagellar transport (IFT) of proteins synthesized in the inner segment and transported through the CC to the outer segment of a photoreceptor cell. The model accounts for the competition between two modes of protein transport: molecular motor-driven transport and diffusion. The obtained solutions made it possible to calculate how the number of protein molecules transported through the CC at a given time depends on their diffusivity. Modeling results were compared with published experimental estimates, and conclusions about possible contributions of diffusion to IFT were made.}, number={6}, journal={COMPUTERS IN BIOLOGY AND MEDICINE}, author={Kuznetsov, A. V.}, year={2013}, month={Jul}, pages={758–764} }
@article{rasipuram_wu_kuznetsov_kuznetsov_levine_jasper_saveliev_2013, title={Submicrometre particle filtration with a dc activated plasma textile}, volume={47}, ISSN={0022-3727 1361-6463}, url={http://dx.doi.org/10.1088/0022-3727/47/2/025201}, DOI={10.1088/0022-3727/47/2/025201}, abstractNote={Plasma textiles are novel fabrics incorporating the advantages of cold plasma and low-cost non-woven or woven textile fabrics. In plasma textiles, electrodes are integrated into the fabric, and a corona discharge is activated within and on the surface of the fabric by applying high voltages above 10 kV between the electrodes. When the plasma textile is activated, submicrometre particles approaching the textile are charged by the deposition of ions and electrons produced by the corona, and then collected by the textile material. A stable plasma discharge was experimentally verified on the surface of the textile that was locally smooth but not rigid. A filtration efficiency close to 100% was observed in experiments conducted on salt particles with diameters ranging from 50 to 300 nm. Unlike conventional fibrous filters, the plasma textile provided uniform filtration in this range, without exhibiting a maximum particle penetration size.}, number={2}, journal={Journal of Physics D: Applied Physics}, publisher={IOP Publishing}, author={Rasipuram, S C and Wu, M and Kuznetsov, I A and Kuznetsov, A V and Levine, J F and Jasper, W J and Saveliev, A V}, year={2013}, month={Dec}, pages={025201} }
@article{wu_jasper_kuznetsov_johnson_rasipurarn_2013, title={Submicron particle filtration in monolith filters - A modeling and experimental study}, volume={57}, ISSN={["1879-1964"]}, DOI={10.1016/j.jaerosci.2012.09.002}, abstractNote={With over a million micron-sized channels per square centimeter arranged in a regular pattern on a thin film, monolith filters have significant potential for submicron aerosol particle filtration, even though the filtration process with this class of filters has not been well studied. In order to better understand the capture mechanisms and the main factors that affect the capture efficiency, so as to build predictive numerical models and to improve the design of monolith filters, the filtration process in monolith filters was investigated both experimentally and numerically. Using an electrostatic particle classifier (EPC) and a condensation particle counter (CPC), the experimental platform measured the capture efficiency of salt particles with diameters ranging from 50–300 nm on two monolith filter samples. Based on the filtration process and the repeating geometric structure, a single unit model was proposed. The drag force, electrostatic force, and Brownian motion are considered as the major forces affecting particle motion. Published theories underestimated the capture efficiency compared to the experimental results. The Brownian motion model and the capture criterion were then empirically modified to gain better agreement with the experiment.}, journal={JOURNAL OF AEROSOL SCIENCE}, publisher={Elsevier BV}, author={Wu, Mengbai and Jasper, Warren J. and Kuznetsov, Andrey V. and Johnson, Nathan and Rasipurarn, Srinivasan C.}, year={2013}, month={Mar}, pages={96–113} }
@article{kuznetsov_nield_2013, title={The Cheng-Minkowycz problem for natural convective boundary layer flow in a porous medium saturated by a nanofluid: A revised model}, volume={65}, ISSN={["0017-9310"]}, DOI={10.1016/j.ijheatmasstransfer.2013.06.054}, abstractNote={The classical Cheng–Minkowycz problem considers natural convection past a vertical plate in a fluid-saturated porous medium. In our previous work we extended the Cheng–Minkowycz problem to the case when a porous medium is saturated by a nanofluid. We utilized Buongiorno’s nanofluid model that includes the effects of Brownian motion and thermophoresis. The major limitation of our previous model was active control of nanoparticle volume fraction at the boundary. Here we revisited our previous model and extended it to the case when the nanofluid particle fraction on the boundary is passively rather than actively controlled. This makes the model physically more realistic than our previous model as well as models employed by other authors simulating nanofluid flow in porous media.}, journal={INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER}, author={Kuznetsov, A. V. and Nield, D. A.}, year={2013}, month={Oct}, pages={682–685} }
@article{nield_kuznetsov_2013, title={The Effect of Heterogeneity on the Onset of Double-Diffusive Convection Induced by Internal Heating in a Porous Medium: A Layered Model}, volume={100}, ISSN={["0169-3913"]}, DOI={10.1007/s11242-013-0206-2}, number={1}, journal={TRANSPORT IN POROUS MEDIA}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2013}, month={Oct}, pages={83–99} }
@article{nield_kuznetsov_2013, title={The Effect of Pulsating Deformation on the Onset of Convection in a Porous Medium}, volume={98}, ISSN={["0169-3913"]}, DOI={10.1007/s11242-013-0168-4}, number={3}, journal={TRANSPORT IN POROUS MEDIA}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2013}, month={Jul}, pages={713–724} }
@article{kuznetsov_nield_2013, title={The Effect of Strong Heterogeneity on the Onset of Convection Induced by Internal Heating in a Porous Medium: A Layered Model}, volume={99}, ISSN={["0169-3913"]}, DOI={10.1007/s11242-013-0175-5}, number={1}, journal={TRANSPORT IN POROUS MEDIA}, author={Kuznetsov, A. V. and Nield, D. A.}, year={2013}, month={Aug}, pages={85–100} }
@article{kuznetsov_nield_2013, title={The Effect of Vertical Throughflow on the Onset of Convection Induced by Internal Heating in a Layered Porous Medium}, volume={100}, ISSN={["0169-3913"]}, DOI={10.1007/s11242-013-0207-1}, number={1}, journal={TRANSPORT IN POROUS MEDIA}, author={Kuznetsov, A. V. and Nield, D. A.}, year={2013}, month={Oct}, pages={101–114} }
@article{nield_kuznetsov_2013, title={The Onset of Convection in a Layered Porous Medium with Vertical Throughflow}, volume={98}, ISSN={["0169-3913"]}, DOI={10.1007/s11242-013-0148-8}, number={2}, journal={TRANSPORT IN POROUS MEDIA}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2013}, month={Jun}, pages={363–376} }
@article{nield_kuznetsov_2013, title={The Onset of Double-Diffusive Convection in a Vertical Cylinder With Vertical Throughflow}, volume={135}, ISSN={["1528-8943"]}, DOI={10.1115/1.4007859}, abstractNote={The effect of vertical throughflow on the onset of convection, induced by an applied vertical temperature gradient in a vertical cylinder is studied analytically using linear stability theory. This problem is important to hydrologists to investigate under what conditions convection is taking place in a well or borehole. The effect of double diffusion is included. Both nonoscillatory and oscillatory situations are studied.}, number={3}, journal={JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2013}, month={Mar} }
@article{kuznetsov_2013, title={The onset of bio-thermal convection induced by a combined effect of gyrotactic and oxytactic microorganisms}, volume={23}, ISSN={["1758-6585"]}, DOI={10.1108/hff-09-2011-0178}, abstractNote={PurposeThe purpose of this paper is to investigate the stability of a suspension containing both gyrotactic and oxytactic microorganisms for the case when the suspension occupies a horizontal layer of finite depth. The lower boundary of the layer is assumed rigid while at the upper boundary both situations of rigid and stress‐free boundary conditions are considered.}, number={6}, journal={INTERNATIONAL JOURNAL OF NUMERICAL METHODS FOR HEAT & FLUID FLOW}, author={Kuznetsov, A. V.}, year={2013}, pages={979–1000} }
@article{kuznetsov_2012, title={A THREE-KINETIC-STATE MODEL OF AXONAL TRANSPORT DRUG DELIVERY}, volume={12}, ISSN={["0219-5194"]}, DOI={10.1142/s021951941100468x}, abstractNote={ This paper develops a model of axonal transport drug delivery that includes three populations (kinetic states) of pharmaceutical agent complexes (PACs), namely PACs transported by dynein motors, PACs freely suspended in the cytosol, and PACs accumulated at the Nodes of Ranvier. The number of model parameters is minimized by recasting governing equations into the dimensionless form. The obtained equations are solved numerically. The dependencies of the three PAC concentrations as well as the diffusion-driven, motor-driven, and total PAC fluxes on the PAC diffusivity and the length of the axon are investigated. Two situations are analyzed: when all kinetic constantans are the same (in this case the dynein-driven PAC flux exceeds the diffusion flux by a large amount) and when kinetic constants describing PAC transition from the freely suspended state are small (in the this case the diffusion-driven flux is the major component of the total flux, but since the diffusion transport mechanism is highly inefficient compared to the motor-driven one for large particles, the total PAC flux is much smaller in this case). }, number={3}, journal={JOURNAL OF MECHANICS IN MEDICINE AND BIOLOGY}, author={Kuznetsov, A. V.}, year={2012}, month={Jun} }
@article{kuznetsov_2012, title={A model of axonal transport drug delivery}, volume={10}, ISSN={["1895-1082"]}, DOI={10.2478/s11534-011-0116-2}, abstractNote={Abstract}, number={2}, journal={CENTRAL EUROPEAN JOURNAL OF PHYSICS}, author={Kuznetsov, Andrey V.}, year={2012}, month={Apr}, pages={320–328} }
@article{kuznetsov_2012, title={A model of axonal transport drug delivery: effects of diffusivity}, volume={28}, ISSN={["2040-7939"]}, DOI={10.1002/cnm.2469}, abstractNote={SUMMARY}, number={11}, journal={INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING}, author={Kuznetsov, A. V.}, year={2012}, month={Nov}, pages={1083–1092} }
@article{kuznetsov_2012, title={An exact solution describing slow axonal transport of cytoskeletal elements: the effect of a finite half-life}, volume={468}, ISSN={["1471-2946"]}, DOI={10.1098/rspa.2012.0061}, abstractNote={This paper presents an exact solution for a two kinetic state model of slow axonal transport that is based on the stop-and-go hypothesis. The model accounts for two populations of cytoskeletal elements (CEs): pausing and running. The model also accounts for a finite half-life of CEs involved in slow axonal transport. It is assumed that initially CEs are injected into the axon such that their concentration forms a rectangular pulse; initially all CEs are assumed to be in the pausing state. Kinetic processes quickly redistribute CEs between the pausing and running states. After less than a minute, equilibrium is established, forming two pulses, representing concentrations of pausing and running CEs, respectively. As these pulses propagate, their shape changes and they turn to bell-shaped waves. The amplitude of the waves decreases, and the waves spread out as they propagate down the axon. The rate of the amplitude decrease is larger for CEs with a shorter half-life, but even if CE half-life is infinitely long, some decrease of the waves' amplitudes is observed. The velocity of the waves' propagation is found to be independent of the CE half-life and is in good agreement with published experimental data for slow axonal transport of neurofilaments.}, number={2147}, journal={PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES}, author={Kuznetsov, A. V.}, year={2012}, month={Nov}, pages={3384–3397} }
@article{kuznetsov_saveliev_rasipuram_kuznetsov_brown_jasper_2012, title={Development of Active Porous Medium Filters Based on Plasma Textiles}, volume={1453}, ISSN={["0094-243X"]}, DOI={10.1063/1.4711186}, abstractNote={Inexpensive, flexible, washable, and durable materials that serve as antimicrobial filters and self-decontaminating fabrics are needed to provide active protection to people in areas regularly exposed to various biohazards, such as hospitals and bio research labs working with pathogens. Airlines and cruise lines need such material to combat the spread of infections. In households these materials can be used in HVAC filters to fight indoor pollution, which is especially dangerous to people suffering from asthma. Efficient filtering materials are also required in areas contaminated by other types of hazardous dust particulates, such as nuclear dust. The primary idea that guided the undertaken study is that a microplasma-generating structure can be embedded in a textile fabric to generate a plasma sheath (“plasma shield”) that kills bacterial agents coming in contact with the fabric. The research resulted in the development of a plasma textile that can be used for producing new types of self-decontaminating ...}, journal={POROUS MEDIA AND ITS APPLICATIONS IN SCIENCE, ENGINEERING, AND INDUSTRY}, publisher={AIP}, author={Kuznetsov, Ivan A. and Saveliev, Alexei V. and Rasipuram, Srinivasan and Kuznetsov, Andrey V. and Brown, Alan and Jasper, Warren}, year={2012}, pages={265–270} }
@article{kuznetsov_2012, title={Effect of kinesin velocity distribution on slow axonal transport}, volume={10}, ISSN={["1644-3608"]}, DOI={10.2478/s11534-012-0051-x}, abstractNote={Abstract}, number={4}, journal={CENTRAL EUROPEAN JOURNAL OF PHYSICS}, author={Kuznetsov, Andrey V.}, year={2012}, month={Aug}, pages={779–788} }
@article{kuznetsov_blinov_avramenko_kuznetsov_2012, title={Error correction in intracellular transport: Numerical investigation of rerouting of a pulse of misdirected axonal cargos in a dendrite}, volume={42}, ISSN={["1879-0534"]}, DOI={10.1016/j.compbiomed.2012.09.011}, abstractNote={This paper develops a transient three-kinetic state model that simulates rerouting of a pulse of axonal cargos that were initially misdirected to a dendrite. The following three cargo populations are included in the model: (i) anterogradely running cargos, (ii) retrogradely running cargos, and (iii) free (diffusion-driven) cargos that are detached from microtubules. The dynamics of cargo concentrations in various kinetic states are studied. It is demonstrated that the profile of the total cargo concentration is comprised of two major components. The first component is a pulse composed of anterogradely running cargos and the second component is a tail behind this pulse that is composed of free (diffusion-driven) and retrogradely running cargos. The total number of misdirected axonal cargos in the dendrite is also computed. The dependence of this quantity on the amount of time that passed from the moment when the pulse entered the dendrite and on kinetic constants describing transition rates between various kinetic states of misdirected cargos is investigated.}, number={12}, journal={COMPUTERS IN BIOLOGY AND MEDICINE}, author={Kuznetsov, A. V. and Blinov, D. G. and Avramenko, A. A. and Kuznetsov, I. A.}, year={2012}, month={Dec}, pages={1196–1203} }
@article{kuznetsov_bubnovich_2012, title={Investigation of simultaneous effects of gyrotactic and oxytactic microorganisms on nanofluid bio-thermal convection in porous media}, volume={15}, DOI={10.1615/jpormedia.v15.i7.20}, abstractNote={This paper develops a theory of nanofluid bio-thermal convection in a fluid-saturated porous layer when the suspension contains two different species of motile microorganisms. The goal is to investigate the combined effect of these two species of microorganisms, nanoparticles, and a vertical temperature variation on the hydrodynamic stability of the layer. Since microorganisms are heavier than the base fluid (water) and swim in the upward direction, they act as a destabilizing agency. It is interesting that if one species of microorganisms is present, the system becomes less sensitive to the concentration of the second species, as long as the concentration of the second species of microorganisms remains small. The effect of the nanoparticles depends on whether their distribution is top heavy or bottom heavy. The effect of the temperature variation is destabilizing when heating from the bottom and stabilizing when cooling from the bottom. The utilization of the linear instability theory makes it possible to decouple the effects of these various agencies and obtain an eigenvalue equation that involves four Rayleigh numbers, each characterizing one of the effects described above.}, number={7}, journal={Journal of Porous Media}, author={Kuznetsov, A. V. and Bubnovich, V.}, year={2012}, pages={617–631} }
@article{kuznetsov_2012, title={MODELING OF ORGANELLE ENTRY IN AN AXON AND DENDRITE}, volume={12}, ISSN={["1793-6810"]}, DOI={10.1142/s0219519412500261}, abstractNote={ The purpose of this paper is to develop a mathematical description of cargo transport in the entrance regions of axons and dendrites. The model accounts for the difference in microtubule (MT) orientation between axons and dendrites: axons have a uniform MT polarity orientation while dendrites have a mixed MT polarity orientation. Because of that, cargos pulled by dynein motors can enter dendrites but cannot enter axons. It is thus assumed that cargos are targeted to axons by associating them with kinesin motors and cargos are targeted to dendrites by associating them with dynein motors. Analytical solutions of the developed equations describing cargo concentrations in the entrance regions of axons and dendrites are obtained. }, number={5}, journal={JOURNAL OF MECHANICS IN MEDICINE AND BIOLOGY}, author={Kuznetsov, A. V.}, year={2012}, month={Dec} }
@inproceedings{kuznetsov_2012, title={Modeling mass transport in axonal transport drug delivery}, DOI={10.1115/ht2012-58025}, abstractNote={This paper presents a model of targeted drug delivery. The model is based on recent experimental results that reported synthesis and pharmacological efficiency tests of a tri-partite complex designed for axonal transport drug delivery. The developed model accounts for two populations of pharmaceutical agent complexes (PACs). The first population of PACs includes those that are transported retrogradely by dynein motors and the second population of PACs includes those that are accumulated in the axon at the Nodes of Ranvier. The transitions between these two populations of PACs are described by first-order reactions. Laplace transform is utilized to obtain an analytical solution of the coupled system of transient equations describing conservations of these two populations of PACs. Results for various combinations of parameter values are presented and their physical significance is discussed.Copyright © 2012 by ASME}, booktitle={Proceedings of the ASME Summer Heat Transfer Conference, 2012, vol 1}, author={Kuznetsov, A. V.}, year={2012}, pages={991–999} }
@article{gangadharan_kuznetsov_zhu_hinestroza_jasper_2012, title={Modeling of Cross-Flow Across an Electrostatically Charged Monolith Filter}, volume={30}, ISSN={["0272-6351"]}, DOI={10.1080/02726351.2011.604394}, abstractNote={The flow field and filtration efficiency of electrostatically charged micro-channel filters under cross-flow conditions were modeled. In our simulations, the fluid flows tangentially to the filter face (cross-flow). Particles with diameters larger than 2 μm were considered in this study, hence, the effects of Brownian motion were not included in the simulations. The influence of particle size, pressure drop, and electrostatic charge on the filtration efficiency was investigated. Measurements from performing electrostatic force microscopy (EFM) on the monolith sample confirmed the presence of charge and gave a qualitative measurement of the charge distribution. Results from the flow simulations indicate that the electrostatic forces increased the particle capture efficiency only at lower pressure drop. At higher pressure drops, electrostatic forces did not significantly increase the capture efficiency of the particles. Also, the capture efficiency of relatively small particles is found to be more dependent on the pressure drop across the filter than that of larger particles.}, number={5}, journal={PARTICULATE SCIENCE AND TECHNOLOGY}, publisher={Informa UK Limited}, author={Gangadharan, S. and Kuznetsov, A. V. and Zhu, H. and Hinestroza, J. and Jasper, W. J.}, year={2012}, pages={461–473} }
@article{kuznetsov_2012, title={Modeling the effect of degradative pathway associated with Nodes of Ranvier on axonal transport drug delivery}, volume={39}, ISSN={["0735-1933"]}, DOI={10.1016/j.icheatmasstransfer.2012.01.012}, abstractNote={The goal of this paper is to develop a mechanistic model of axonal transport drug delivery. The model accounts for the dynamics of transport of pharmaceutical agent complexes (\PACs) by dynein motors along microtubules (MTs) from the axon periphery toward the neuron soma, PAC accumulation in the axon, and PAC transport out of the axon via a degradative pathway that is associated with Nodes of Ranvier. The model assumes two populations of PACs: (1) PACs that are in retrograde transit propelled by dynein motors and (2) PACs accumulated at Nodes of Ranvier. The obtained governing equations describing the dynamics of these two PAC populations are transformed into dimensionless form and solved analytically utilizing Laplace transform. The obtained results reveal that for certain values of kinetic constants involved in the model the concentration of accumulated PACs can be independent of the position in the axon. To explain the obtained result this case is analyzed separately. Physical significance of computational results is discussed.}, number={3}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Kuznetsov, A. V.}, year={2012}, month={Mar}, pages={325–330} }
@article{kuznetsov_2012, title={Modeling transport of tau in an axon after a photobleaching experiment}, volume={39}, ISSN={["0735-1933"]}, DOI={10.1016/j.icheatmasstransfer.2012.01.013}, abstractNote={Abstract The goal of this paper is to apply Laplace transform method to solving the problem of recovery of concentration of tau protein in an axon after a photobleaching experiment that is described in S. Konzack, E. Thies, A. Marx, E. Mandelkow, E. Mandelkow, Swimming against the tide: Mobility of the microtubule-associated protein tau in neurons, Journal of Neuroscience. 27 (2007) 9916-9927. The model accounts for two populations of tau molecules: those that are suspended in the cytoplasm, free to diffuse in the axon, and those that are bound to microtubules (MTs). The exchange of tau molecules between these two populations is modeled by first-order reactions. It is shown that governing equations for this model can be solved by Laplace transform method, although the last step of the solution, finding the inverse Laplace transform, has to be done numerically, which leads to a hybrid analytical and numerical solution technique. The numerical inversion of the Laplace transform is performed utilizing a method based on Fourier series expansion of the inverse transform.}, number={3}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Kuznetsov, A. V.}, year={2012}, month={Mar}, pages={331–335} }
@article{kuznetsov_2012, title={Modelling transport of layered double hydroxide nanoparticles in axons and dendrites of cortical neurons}, volume={15}, ISSN={["1025-5842"]}, DOI={10.1080/10255842.2011.585977}, abstractNote={This paper develops a model of nanoparticle transport in neurons. It is assumed that nanoparticles are transported inside endocytic vesicles by a combined effect of dynein-driven transport and diffusion. It is further assumed that in axons nanoparticles are internalised only at axon terminals, whereas in dendrites nanoparticles can enter through the entire plasma membrane. This causes differences in transport of nanoparticles in axons and dendrites; these differences are investigated in this paper. Another difference is microtubule (MT) orientation in axons and dendrites; in axons, all MTs have their plus-ends oriented towards the axon terminal; in a proximal region of a dendrite, MTs have mixed orientation, whereas in a distal dendritic region the MT orientation is similar to that in an axon. It is shown that if molecular-motor-driven transport were powered by dynein alone, such MT orientation in a dendrite would result in a region of nanoparticle accumulation located at the border between the proximal and distal dendritic regions.}, number={12}, journal={COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING}, author={Kuznetsov, A. V.}, year={2012}, month={Dec}, pages={1263–1271} }
@article{kuznetsov_2012, title={NANOFLUID BIOCONVECTION IN A HORIZONTAL FLUID-SATURATED POROUS LAYER}, volume={15}, ISSN={["1091-028X"]}, DOI={10.1615/jpormedia.v15.i1.20}, abstractNote={The theory of nanofluid bioconvection in porous media is presented. The major motivation of using bioconvection is to enhance mixing and mass transfer in microvolumes, but before this goal can be implemented in practical microdevices, nanofluid bioconvection must be understood at the fundamental level. The developed theory is applied to investigating the onset of nanofluid bioconvection in a horizontal porous layer heated from below. The cases of non-oscillatory and oscillatory convection are investigated. The obtained results indicate that the effect of microorganisms on the stability of the suspension may depend on the value of bioconvection Peclet number.}, number={1}, journal={JOURNAL OF POROUS MEDIA}, author={Kuznetsov, A. V.}, year={2012}, pages={11–27} }
@article{kuznetsov_2012, title={NANOFLUID BIOCONVECTION IN POROUS MEDIA: OXYTACTIC MICROORGANISMS}, volume={15}, ISSN={["1934-0508"]}, DOI={10.1615/jpormedia.v15.i3.30}, abstractNote={This paper investigates a new type of a nanofluid that contains, in addition to nanoparticles, oxytactic motile microorganisms. One of the paradigmic problems, the Horton−Rogers−Lapwood problem (i.e., the stability of a horizontal fluid-saturated porous layer of finite depth), is solved for this new nanofluid. The stability of this nanofluid is controlled by three agencies: the nanoparticle distribution, the density stratification induced by the vertical temperature gradient, and the density stratification induced by upswimming of oxytactic microorganisms. Both non-oscillatory and oscillatory instability situations are investigated. Oscillatory instability is shown to be possible when the nanoparticle distribution is stabilizing (bottom heavy) and the vertical temperature variation is destabilizing (heating from the bottom). It is also shown that the presence of oxytactic microorganisms makes the suspension less stable but tends to destroy the oscillatory instability in favor of non-oscillatory instability.}, number={3}, journal={JOURNAL OF POROUS MEDIA}, author={Kuznetsov, A. V.}, year={2012}, pages={233–248} }
@article{kuznetsov_2012, title={Nanofluid bioconvection: interaction of microorganisms oxytactic upswimming, nanoparticle distribution, and heating/cooling from below}, volume={26}, ISSN={["0935-4964"]}, DOI={10.1007/s00162-011-0230-1}, number={1-4}, journal={THEORETICAL AND COMPUTATIONAL FLUID DYNAMICS}, author={Kuznetsov, A. V.}, year={2012}, month={Jan}, pages={291–310} }
@article{avramenko_blinov_shevchuk_kuznetsov_2012, title={Symmetry analysis and self-similar forms of fluid flow and heat-mass transfer in turbulent boundary layer flow of a nanofluid}, volume={24}, ISSN={["1089-7666"]}, DOI={10.1063/1.4753945}, abstractNote={Heat, momentum, and mass transport in turbulent boundary layer nanofluid flow over a flat plate were investigated. Boundary layer equations were reduced to self-similar forms and solved numerically. The Lie group technique, which is based on the symmetry properties of governing equations, was used to derive self-similar forms of these equations. Turbulent viscosity was predicted using the mixing-length model. Also, dependences of physical properties (viscosity, thermal conductivity, and diffusion coefficients) on the nanofluid concentration and temperature were accounted for. Influences of different dimensionless parameters and nanoparticle concentration on the velocity and temperature profiles, as well as on the relative Nusselt number and skin-friction coefficient, were investigated.}, number={9}, journal={PHYSICS OF FLUIDS}, author={Avramenko, A. A. and Blinov, D. G. and Shevchuk, I. V. and Kuznetsov, A. V.}, year={2012}, month={Sep} }
@article{nield_kuznetsov_2012, title={The Effect of Strong Heterogeneity and Strong Throughflow on the Onset of Convection in a Porous Medium: Non-Periodic Global Variation}, volume={91}, ISSN={["1573-1634"]}, DOI={10.1007/s11242-011-9881-z}, number={3}, journal={TRANSPORT IN POROUS MEDIA}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2012}, month={Feb}, pages={927–938} }
@article{kuznetsov_nield_2012, title={The Effect of Strong Heterogeneity and Strong Throughflow on the Onset of Convection in a Porous Medium: Periodic and Localized Variation}, volume={92}, ISSN={["1573-1634"]}, DOI={10.1007/s11242-011-9902-y}, number={2}, journal={TRANSPORT IN POROUS MEDIA}, author={Kuznetsov, A. V. and Nield, D. A.}, year={2012}, month={Mar}, pages={289–298} }
@article{nield_kuznetsov_2012, title={The Onset of Convection in a Layer of a Porous Medium Saturated by a Nanofluid: Effects of Conductivity and Viscosity Variation and Cross-Diffusion}, volume={92}, ISSN={["0169-3913"]}, DOI={10.1007/s11242-011-9935-2}, number={3}, journal={TRANSPORT IN POROUS MEDIA}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2012}, month={Apr}, pages={837–846} }
@article{kuznetsov_nield_2012, title={The onset of double-diffusive convection in a vertical cylinder occupied by a heterogeneous porous medium with vertical throughflow}, volume={95}, DOI={10.1007/s11242-012-0045-6}, number={2}, journal={Transport in Porous Media}, author={Kuznetsov, A. V. and Nield, D. A.}, year={2012}, pages={327–336} }
@article{kuznetsov_2011, title={A four kinetic state model of fast axonal transport: Model formulation and perturbation solution}, volume={9}, ISSN={["1895-1082"]}, DOI={10.2478/s11534-010-0032-x}, abstractNote={Abstract}, number={1}, journal={CENTRAL EUROPEAN JOURNAL OF PHYSICS}, author={Kuznetsov, Andrey V.}, year={2011}, month={Feb}, pages={146–156} }
@article{nield_kuznetsov_2011, title={A three-velocity three-temperature model for a tridisperse porous medium: Forced convection in a channel}, volume={54}, DOI={10.1016/j.ijheatmasstransfer.2011.02.013}, abstractNote={A three-velocity three-temperature model for tridisperse porous media is formulated. Using the model, an analytic solution is obtained for the problem of forced convection in a channel between parallel plane walls that are held either at uniform temperature or uniform heat flux. In each case, Nusselt number values are given as functions of conductivity ratios, velocity ratios, volume fractions, and internal heat exchange parameters.}, number={11-12}, journal={International Journal of Heat and Mass Transfer}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2011}, pages={2490–2498} }
@article{kuznetsov_2011, title={An analytical solution describing retrograde viral transport in an axon}, volume={38}, ISSN={["1879-0178"]}, DOI={10.1016/j.icheatmasstransfer.2011.08.016}, abstractNote={An analytical solution representing a wave of viral concentration as it propagates from the axon synapse toward the neuron soma is obtained. The obtained solution is based on a model of molecular motor-assisted retrograde transport of a neurotropic virus in an axon of a peripheral nervous system. It is established that the velocity of the viral concentration wave is almost independent of the rate of viral destruction in the axon, but depends on viral diffusivity, especially right after viral uptake at the synapse, when viral concentration gradient is large. As time progresses, the velocity of the viral concentration wave approaches that of a dynein motor, which indicates that for a large time viral transport in an axon is almost exclusively motor-driven.}, number={10}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Kuznetsov, A. V.}, year={2011}, month={Dec}, pages={1313–1316} }
@article{kuznetsov_2011, title={Analytical investigation of various regimes of retrograde trafficking of neurotropic viruses in axons}, volume={9}, ISSN={["1895-1082"]}, DOI={10.2478/s11534-011-0051-2}, abstractNote={Abstract}, number={5}, journal={CENTRAL EUROPEAN JOURNAL OF PHYSICS}, author={Kuznetsov, Andrey V.}, year={2011}, month={Oct}, pages={1372–1378} }
@article{kuznetsov_2011, title={Analytical solution of equations describing slow axonal transport based on the stop-and-go hypothesis}, volume={9}, ISSN={["1895-1082"]}, DOI={10.2478/s11534-010-0066-0}, abstractNote={Abstract}, number={3}, journal={CENTRAL EUROPEAN JOURNAL OF PHYSICS}, author={Kuznetsov, Andrey V.}, year={2011}, month={Jun}, pages={662–673} }
@article{kuznetsov_2011, title={Bio-thermal convection induced by two different species of microorganisms}, volume={38}, ISSN={["1879-0178"]}, DOI={10.1016/j.icheatmasstransfer.2011.02.006}, abstractNote={This paper develops a theory of bio-thermal convection in a suspension that contains two species of microorganisms exhibiting different taxes, gyrotactic and oxytactic microorganisms. The developed theory is applied to investigating the onset of bio-thermal convection in such a suspension occupying a horizontal layer of finite depth. A linear stability analysis is utilized to derive the equations for the amplitudes of disturbances. The obtained eigenvalue problem is solved by the Galerkin method. The case of non-oscillatory instability in a layer with a rigid lower boundary and a stress-free upper boundary is investigated. The resulting eigenvalue equation relates three Rayleigh numbers, the traditional Rayleigh number (Ra) and two bioconvection Rayleigh numbers, one for gyrotactic (Rbg) and one for oxytactic (Rbo) microorganisms. The neutral stability boundary is presented in the form of a diagram showing that boundary in the (Ra, Rag) plane for different values of Rao.}, number={5}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Kuznetsov, A. V.}, year={2011}, month={May}, pages={548–553} }
@article{kuznetsov_2011, title={Coupling a dynein transport model with a model of anterograde and retrograde transport of intracellular organelles}, volume={38}, ISSN={["0735-1933"]}, DOI={10.1016/j.icheatmasstransfer.2011.04.024}, abstractNote={Abstract A model of fast axonal transport of organelles that accounts for dynein transport in an inactive state toward the axonal synapse is developed. It is assumed that anterograde transport of inactive dynein in an axon is powered by kinesin motors. It is further assumed that the probability of organelle attachment to a dynein motor is directly proportional to the concentration of free dynein motors available at a particular location in the axon. The results predicted by two models (the first one is that which incorporates dynein transport and the second one is the traditional model that does not incorporate dynein transport) are compared. The obtained results suggest that the availability of dynein motors in a particular location in an axon can be a factor limiting fast axonal transport.}, number={7}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Kuznetsov, A. V.}, year={2011}, month={Aug}, pages={833–837} }
@article{wu_kuznetsov_jasper_2011, title={Distribution characteristics of exhaust gases and soot particles in a wall-flow ceramics filter}, volume={42}, ISSN={["1879-1964"]}, DOI={10.1016/j.jaerosci.2011.04.003}, abstractNote={An inhomogeneous soot distribution in a diesel particulate filter may deteriorate its behavior and result in higher pressure drops and fuel consumption. This will cause mechanical stresses on the filter due to temperature gradients resulting from the non-uniformly burning of soot during regeneration. The purpose of this paper is to investigate the flow distribution of the exhaust gas entering into a diesel particulate filter, the turbulent motion of diesel soot particles in the inlet header, and their deposition and distribution in the front surface of a diesel particulate filter. A Lagranian continuous random walk (CRW) model is developed to simulate soot particulate motion, which considers a succession of uncorrelated random forcing and drift corrections. The effects of particle inertia, turbulent fluctuation, and lift on the particle motion and trajectory are analyzed. Correlations of the uniformity index of the exhaust gas and soot particles with the flow rate, soot loading, and inlet expansion angle are evaluated. The results show that there is a two-peak phenomenon in the soot distribution at the front entrance of the filter, which is comprised of a peak in the central area due to inertia and a second peak in the periphery owing to diffusion and recirculation action. Exhaust flow rates and the inlet expansion angle have a major influence on the flow uniformity and soot uniformity, while soot loading has a slightly smaller effect on soot uniformity.}, number={7}, journal={JOURNAL OF AEROSOL SCIENCE}, publisher={Elsevier BV}, author={Wu, Guojiang and Kuznetsov, Andrey V. and Jasper, Warren J.}, year={2011}, month={Jul}, pages={447–461} }
@article{kuznetsov_nield_2011, title={Double-diffusive natural convective boundary-layer flow of a nanofluid past a vertical plate}, volume={50}, ISSN={["1290-0729"]}, DOI={10.1016/j.ijthermalsci.2011.01.003}, abstractNote={The double-diffusive natural convective boundary-layer flow of a nanofluid past a vertical plate is studied analytically. The model used for the binary nanofluid incorporates the effects of Brownian motion and thermophoresis. In addition the thermal energy equations include regular diffusion and cross-diffusion terms. A similarity solution is presented. Numerical calculations were performed in order to obtain correlation formulas giving the reduced Nusselt number as a function of the various relevant parameters.}, number={5}, journal={INTERNATIONAL JOURNAL OF THERMAL SCIENCES}, author={Kuznetsov, A. V. and Nield, D. A.}, year={2011}, month={May}, pages={712–717} }
@article{kuznetsov_avramenko_blinov_2011, title={Effect of cytoskeletal element degradation on merging of concentration waves in slow axonal transport}, volume={9}, ISSN={["1895-1082"]}, DOI={10.2478/s11534-010-0116-7}, abstractNote={Abstract}, number={4}, journal={CENTRAL EUROPEAN JOURNAL OF PHYSICS}, author={Kuznetsov, Andrey V. and Avramenko, Andriy A. and Blinov, Dmitry G.}, year={2011}, month={Aug}, pages={898–908} }
@article{kuznetsov_2011, title={Effect of pharmaceutical agent degradation on axonal transport drug delivery: An analytical solution for a transient situation}, volume={38}, ISSN={["0735-1933"]}, DOI={10.1016/j.icheatmasstransfer.2011.08.018}, abstractNote={This paper is motivated by recent experimental research that demonstrated pharmacological efficiency of axonal transport drug delivery. The purpose is to develop a model of this process and to study how the rate of destruction of pharmaceutical agent complexes (PACs) affects their transport in the axon. The model includes two populations of PACs: PACs in the state when they are driven retrogradely (from the axon terminal toward the neuron soma) by dynein motors and PACs residing in the accumulated state (but can still be re-released to the dynein-driven state). The coupling between the kinetic states is accounted for by first-order reactions. Utilizing Laplace transform, analytical solutions for concentrations of these two populations of PACs are obtained. The effect of PAC destruction is investigated for different values of other parameters. It is shown that the shapes of the waves describing the PAC concentrations can be significantly affected by transport parameters.}, number={10}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Kuznetsov, A. V.}, year={2011}, month={Dec}, pages={1317–1321} }
@article{diaz_kuznetsov_2011, title={Effect of the flow in a printing nip on paper runnability during sheetfed offset printing}, volume={64}, number={2}, journal={Appita Journal}, author={Diaz, F. J. and Kuznetsov, A. V.}, year={2011}, pages={158-} }
@article{nield_kuznetsov_2011, title={Forced Convection in a Channel Partly Occupied by a Bidisperse Porous Medium: Symmetric Case}, volume={133}, ISSN={["1528-8943"]}, DOI={10.1115/1.4003667}, abstractNote={An analytic solution is obtained for the problem of fully developed forced convection in a channel between parallel plane walls, partly occupied by a bidisperse porous medium (BDPM) and partly by a fluid clear of solid material, the distribution of material being symmetrical with the BDPM forming either the core or the sheath portion of the channel. The case of uniform flux boundaries is considered. For the porous medium, a two-velocity two-temperature model based on Darcy’s law is employed and the Beavers–Joseph interface condition is imposed. In each case, Nusselt number values are obtained in terms of various parameters.}, number={7}, journal={JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2011}, month={Jul} }
@article{zheng_kuznetsov_roberts_paxson_2011, title={Influence of Geometry on Starting Vortex and Ejector Performance}, volume={133}, ISSN={["0098-2202"]}, DOI={10.1115/1.4004082}, abstractNote={For many propulsion devices, the thrust may be augmented considerably by adding a passive ejector, and these devices are especially attractive for unsteady propulsion systems such as pulse detonation engines and pulsejets. Starting vortices from these unsteady devices dominate the flowfield and control to a great extent the level of the thrust augmentation. Therefore, it is of fundamental interest to understand the geometric influences on the starting vortex and how these manifest themselves in augmenter/ejector performance. An unsteady Reynolds averaged Navier–Stokes calculation was used to study the physics of a starting vortex generated at the exit of a pulsed jet and its interaction with an ejector. A 50 cm long pulsejet (typical hobby scale, allowing comparison with experimental data) with a circular exit was modeled as the resonant driving source and used to suggest an optimal ejector geometry and relative position. Computed limit-cycle thrust augmentation values compared favorably to experimentally obtained values for the same ejector geometries. Results suggest that the optimal diameter of the ejector is related to its relative position, dictated by the trajectory of the vortex toroid. The effect of the length of the ejector (which determines the natural frequency of the ejector, related to the acoustic processes occurring in the ejector) on overall performance was also investigated and shown to be less important than the ejector diameter.}, number={5}, journal={JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME}, author={Zheng, Fei and Kuznetsov, Andrey V. and Roberts, William L. and Paxson, Daniel E.}, year={2011}, month={May} }
@article{kuznetsov_avramenko_blinov_2011, title={Investigation of the role of diffusivity on spreading, rate, and merging of the bell-shaped waves in slow axonal transport}, volume={27}, ISSN={["2040-7939"]}, DOI={10.1002/cnm.1417}, abstractNote={This paper investigates the role of diffusivity on spreading, rate, and merging of two waves transporting the same type of cytoskeletal elements (CEs) in slow axonal transport. The two waves (each wave physically represents the total probability density function for the CEs) can be generated by simultaneous microinjections of radiolabeled CEs in two different locations. Alternatively, two waves, one behind another, can be produced by injecting CEs at the same location twice, with a time interval between the injections. Since the waves become wider as they propagate downstream, the two waves eventually merge; this results in the formation of a single wave that moves down the axon. The amplitudes of the waves (before as well as after they merge) decrease as the waves propagate downstream; in addition, the waves spread out during their propagation. The waves spread out faster when diffusivity of free CEs is increased; this agrees with experimental data for the transport of neurofilaments, which are characterized by smaller diffusivity, versus transport of tubulin oligomers, which are characterized by larger diffusivity. The average velocity of CE transport first increases (which is explained by the effect of the initial condition; this effect is somewhat artificial) and then attains an asymptotic value. The case of merging of three waves is also briefly investigated. Copyright © 2010 John Wiley & Sons, Ltd.}, number={7}, journal={INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING}, author={Kuznetsov, A. V. and Avramenko, A. A. and Blinov, D. G.}, year={2011}, month={Jul}, pages={1040–1053} }
@article{kuznetsov_2011, title={Method of modelling intracellular transport in branching neurites: application to axons and dendrites of Drosophila sensory neurons}, volume={14}, ISSN={["1476-8259"]}, DOI={10.1080/10255841003664727}, abstractNote={This paper develops a method of calculating the transport of intracellular organelles in neurons with branching neurites which is based on the Smith–Simmons equations of motor-assisted transport. The method is aimed at understanding the effects of microtubule (MT) polarity orientation in branching neurites on transport of organelles at the fundamental level. The method is applied to calculating the organelle transport in axons and dendrites of Drosophila neurons, using the map of MT orientation in such neurons developed by Stone et al. (Mol Biol Cell 19:4122–4129, 2008). The proximal dendrite is assumed to branch and form two distal dendrites. Two different MT polarity arrangements in a proximal dendrite are considered, and implications of these MT arrangements on organelle transport are analysed. It is demonstrated that the MT arrangement found in Drosophila dendrites (MTs have their minus ends out in a proximal dendrite) results in much more efficient motor-driven transport than the structure with a mixed MT orientation in proximal dendrites.}, number={3}, journal={COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING}, author={Kuznetsov, A. V.}, year={2011}, pages={239–251} }
@article{kuznetsov_2011, title={Modeling Bidirectional Transport of New and Used Organelles in Fast Axonal Transport in Neurons}, volume={133}, ISSN={["0022-1481"]}, DOI={10.1115/1.4002304}, abstractNote={This paper develops a model for simulating transport of newly synthesized material from the neuron body toward the synapse of the axon as well as transport of misfolded and aggregated proteins back to the neuron body for recycling. The model demonstrates that motor-assisted transport, much similar to diffusion, can occur due to a simple concentration difference between the cell body and the synapse; organelles heading to the synapse do not need to attach preferably to plus-end-directed molecular motors, same as organelles heading to the neuron body for recycling do not need to attach preferably to minus-end-directed molecular motors. The underlying mechanics of molecular-motor-assisted transport is such that organelles would be transported to the right place even if new and used organelles had the same probability of attachment to plus-end-directed (and minus-end-directed) motors. It is also demonstrated that the axon with organelle traps and a region with a reversed microtubule polarity would support much smaller organelle fluxes of both new and used organelles than a healthy axon. The flux of organelles is shown to decrease as the width of organelle traps increases.}, number={1}, journal={JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME}, author={Kuznetsov, A. V.}, year={2011}, month={Jan} }
@article{kuznetsov_2011, title={Modeling bidirectional transport of quantum dot nanoparticles in membrane nanotubes}, volume={232}, ISSN={["0025-5564"]}, DOI={10.1016/j.mbs.2011.04.008}, abstractNote={This paper develops a model of transport of quantum dot (QD) nanoparticles in membrane nanotubes (MNTs). It is assumed that QDs are transported inside intracellular organelles (called here nanoparticle-loaded vesicles, NLVs) that are propelled by either kinesin or dynein molecular motors while moving on microtubules (MTs). A vesicle may have both types of motors attached to it, but the motors are assumed to work in a cooperative fashion, meaning that at a given time the vesicle is moved by either kinesin or dynein motors. The motors are assumed not to work against each other, when one type of motors is pulling the vesicle, the other type is inactive. From time to time the motors may switch their roles: passive motors can become active motors and vice versa, resulting in the change of the vesicle’s direction of motion. It is further assumed that QDs can escape NLVs and become free QDs, which are then transported by diffusion. Free QDs can be internalized by NLVs. The effects of two possible types of MT orientation in MNTs are investigated: when all MTs have a uniform polarity orientation, with their plus-ends directed toward one of the cells connected by an MNT, and when MTs have a mixed polarity orientation, with half of MTs having their plus-ends directed toward one of the cells and the other half having their plus-ends directed toward the other cell. Computational results are presented for three cases. The first case is when organelles are as likely to be transported by kinesin motors as by dynein motors. The second case is when organelles are more likely to be transported by kinesin motors than by dynein motors, and the third case is when NLVs do not associate with dynein motors at all.}, number={2}, journal={MATHEMATICAL BIOSCIENCES}, author={Kuznetsov, A. V.}, year={2011}, month={Aug}, pages={101–109} }
@article{kuznetsov_2011, title={Modeling of retrograde nanoparticle transport in axons and dendrites}, volume={38}, ISSN={["0735-1933"]}, DOI={10.1016/j.icheatmasstransfer.2011.03.015}, abstractNote={This paper presents a pioneering modeling study on nanoparticle internalization and transport in neurons. The model developed in this paper is based on recent experimental results that indicate that after entering a neurite by endocytosis, nanoparticles are transported toward the neuron soma in endocytic vesicles by retrograde molecular-motor-driven transport. Experimental results also indicate that nanoparticles enter axons at axon terminals while in dendrites they enter through the entire plasma membrane. The model equations developed in this paper are based on these experimental observations. The analytical solution of these equations is obtained; the solution predicts the distribution of the concentration of nanoparticles associated with free nanoparticle-loaded vesicles (NLVs) (not transported on microtubules (MTs)) as well as the distribution of the concentration of nanoparticles associated with NLVs transported on MTs by dynein motors. The fluxes of nanoparticles by diffusion and motor-driven transport as well as the total (combined) flux of nanoparticles are also predicted.}, number={5}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Kuznetsov, A. V.}, year={2011}, month={May}, pages={543–547} }
@article{kuznetsov_2011, title={Modelling active transport in Drosophila unipolar motor neurons}, volume={14}, ISSN={["1025-5842"]}, DOI={10.1080/10255842.2010.515983}, abstractNote={This paper develops a model for simulating organelle transport in Drosophila unipolar motor neurons. The paper is motivated by a recent experimental investigation by Stone et al. (Microtubules have opposite orientation in axons and dendrites of Drosophila neurons. Mol Biol Cell.19:4122-4129) who proposed a map of microtubule (MT) orientation in Drosophila neurons, and explained why dynein mutations selectively impede dendritic growth without having much effect on axonal growth. Two different approaches to modelling the effect of dynein mutations are utilised: one through assuming a reduced average velocity of a dynein mutant motor and the other through assuming its decreased processivity (an increased detachment rate from MTs). Modified Smith–Simmons equations are used for developing a continuum model of the process. Distributions of organelle concentrations as well as distributions of diffusion, motor-driven and total organelle fluxes are simulated.}, number={12}, journal={COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING}, author={Kuznetsov, A. V.}, year={2011}, pages={1117–1131} }
@article{kuznetsov_2011, title={Nanofluid bio-thermal convection: simultaneous effects of gyrotactic and oxytactic micro-organisms}, volume={43}, ISSN={["0169-5983"]}, DOI={10.1088/0169-5983/43/5/055505}, abstractNote={This paper investigates the onset of nanofluid bio-thermal convection in a horizontal layer of finite depth for the case when the suspension contains two species of motile micro-organisms exhibiting different taxes, gyrotactic and oxytactic micro-organisms. The obtained instability problem is controlled by four agencies, namely by distributions of nanoparticles, gyrotactic and oxytactic micro-organisms and by the vertical temperature variation. The utilization of the linear instability theory makes it possible to decouple the effects of these agencies and obtain an eigenvalue equation that involves four Rayleigh numbers: the nanoparticle Rayleigh number, the bioconvection gyrotactic and oxytactic Rayleigh numbers, and the traditional thermal Rayleigh number. Each Rayleigh number represents the effect of one of the four aforementioned agencies. Previously obtained results are recovered for limiting cases. The effects of different agencies on the boundary of marginal non-oscillatory instability are investigated.}, number={5}, journal={FLUID DYNAMICS RESEARCH}, author={Kuznetsov, A. V.}, year={2011}, month={Oct} }
@article{kuznetsov_2011, title={Nanofluid bioconvection in water-based suspensions containing nanoparticles and oxytactic microorganisms: oscillatory instability}, volume={6}, ISSN={["1556-276X"]}, DOI={10.1186/1556-276x-6-100}, abstractNote={Abstract}, journal={NANOSCALE RESEARCH LETTERS}, author={Kuznetsov, Andrey V.}, year={2011} }
@article{kuznetsov_2011, title={Non-oscillatory and oscillatory nanofluid bio-thermal convection in a horizontal layer of finite depth}, volume={30}, ISSN={["1873-7390"]}, DOI={10.1016/j.euromechflu.2010.10.007}, abstractNote={The onset of bio-thermal convection in a suspension containing both nanoparticles and gyrotactic microorganisms, such as algae, is considered. Physical mechanisms responsible for the slip velocity between the nanoparticles and the base fluid, such as Brownian motion and thermophoresis, are included in the model. The suspension occupies a horizontal layer of finite depth. The lower boundary of the layer is assumed rigid while at the upper boundary both cases of either rigid or stress-free top boundaries are considered. A linear instability analysis is performed and the resulting eigenvalue problem is solved analytically using the Galerkin method. The cases of oscillatory and non-oscillatory convection are studied. Investigation of the dependence of the thermal Rayleigh number on the nanoparticle Rayleigh number and the bioconvection Rayleigh number is performed. The boundaries of oscillatory and non-oscillatory instability are established. The effect of nanoparticles can be either stabilizing or destabilizing, depending on whether the basic nanoparticle distribution is bottom-heavy or top-heavy. The effect of upswimming microorganisms is generally destabilizing.}, number={2}, journal={EUROPEAN JOURNAL OF MECHANICS B-FLUIDS}, author={Kuznetsov, A. V.}, year={2011}, pages={156–165} }
@article{nield_kuznetsov_2011, title={Onset of Convection in a Porous Medium with Strong Vertical Throughflow}, volume={90}, ISSN={["1573-1634"]}, DOI={10.1007/s11242-011-9821-y}, number={3}, journal={TRANSPORT IN POROUS MEDIA}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2011}, month={Dec}, pages={883–888} }
@article{vadasz_kuznetsov_2011, title={Special Issue on Heat and Mass Transfer in Biosystems}, volume={133}, ISSN={["0022-1481"]}, DOI={10.1115/1.4002222}, abstractNote={The involvement of the heat transfer community in the research related to heat and mass transfer in biosystems increases rapidly and covers a wide variety of applications. While the past involved mainly topics of cryogenics and other related fields the current involvement is substantially wider and covers diverse biological fields and applications. The present special issue dedicated to heat and mass transfer in biosystems captures only a portion of this wide topical potential for biosystems research. The objective of this special issue is to report the state of the art on some of the research conducted in this field and motivate the heat transfer community, which is uniquely qualified to make a valuable contribution in providing fundamental understanding of transport of heat, mass, and momentum occurring in biological and biologically inspired systems, to become more involved in this field of research. In particular, applying the engineering way of thinking can be especially useful in developing the fundamental understanding, the governing principles, mechanistic explanations, and predictive modeling for functioning of biological systems. Application of the engineering point of view (through identification, formulation, and solution to bioengineering problems as well as designing machines and systems based on fundamental conservation laws) can usefully complement many biological research efforts and lead to new breakthroughs in this area. Among the topics covered in this special issue are targeted drug delivery, heat generation in nanoparticles with potential application to cancer treatment, tissue engineering by using irreversible electroporation to minimize tissue damage due to Joules heating, temperature distribution in cryosurgery, facilitating transdermal drug delivery via skin electroporation, modeling of microorganism growth including the lag phase, human eye response to thermal disturbances, modeling of bioheat transfer, formation of organelle traps in an axon providing a mechanistic explanation of the onset of Alzheimers disease, the use of micro-cantilever biosensors for detection of microorganisms, and the application of the constructal theory to biophysical systems.The issue starts with a general topic of applications of the constructal law (this law postulates that the direction of systems evolution is such that it obtains easier access to currents that flow through it) in a paper by Bejan and Lorente. The paper considers applications of the constructal law to various biophysical systems. A novel method of targeted drug delivery (of an anti-cancer drug for example) to lung sites via utilization of a new smart inhaler system is then introduced by Kleinstreuer and Zhang. A correlation between the heat generation rate in nanoparticles (due to applying an alternative current at a specific frequency to a water-cooled coil, which thus generates an alternating magnetic field) and the density of the micro-CT images is presented by Attaluri et al. This correlation is important for understanding basic issues of using nanoparticles for cancer treatment. Evidence that parameters for irreversible electroporation can be chosen in such a way that minimizes the damage due to Joule heating to the tissue is demonstrated with the help of numerical modeling by Phillips et al.. Shitzer presents a comprehensive review of analytical and numerical studies on temperature distributions in cryosurgery; in vitro and in vivo experimental data used for validating these results are also discussed. The situations involving both surface application as well as insertion of cryoprobes are analyzed. Results of analytical modeling of biological media or heat management devices with a nonuniform geometry as a combination of convergent, uniform, and/or divergent configurations is presented by Mahjoob and Vafai. Kuznetsov develops a new model for the formation of organelle traps in an axon with regions where microtubule polarity has been reversed by the formation of microtubule swirls. Biological data link the formation of such microtubule swirl regions to traffic jams in axons that lead to various neurological disorders, such as Alzheimers disease. The developed theory demonstrates how the reversal of microtubule polarity results in the formation of organelle traps for both newly synthesized and used organelles, thus providing a mechanistic explanation of the onset of Alzheimers disease. Vadasz and Vadasz present a generic theoretical mechanism for microbial growth, including the lag phase that reveals the profound impact of the metabolic process on the growth. The theoretical model provides excellent matching to experimental data of microbial growth. Systematical reviews of four existing models of a human eye response to thermal disturbances are presented by Shafahi and Vafai. The physical phenomena included in the models, strengths and limitations of the models in simulating eye thermal response to various ambient conditions, blood temperature, and various thermophysical and biological parameters are discussed. Different models of bioheat transfer are introduced by Wang and Fan. Different approaches for obtaining constitutive relations for the heat flux, including Fourier law, Cattaneo−Vernotte theory, and dual-phase lagging theory are presented. The strengths and limitations of various bioheat models, including Pennes, Wulff, Klinger, Chen and Holmes, dual-phase-lagging, as well as some other models are discussed. A comprehensive overview of existing mathematical models of skin electroporation, which is a promising technique of causing a structural alternation in the uppermost skin layer, the stratum corneum, with the aim of facilitating transdermal drug delivery is presented by Becker. Special attention is given to developing a thermodynamic model of electroporation, which is based on the idea that a large current density through the pore causes lipids composing the stratum corneum to undergo a phase transition. Application of microcantilever biosensors for detection of microorganism is investigated experimentally by Tzeng et al. They explored the use of specific carbohydrate receptors for the functionalization of nanoparticles and demonstrated their binding specificities and their ability to mediate aggregations of targeted bacteria.We would like to extend our special thanks to the authors of the special issue and to the reviewers for helping to elevate the quality of the papers. We are also thankful to the Editor, Professor Yogesh Jaluria, for providing this forum to discuss this emerging field. Special thanks to the Editorial Assistant, Shefali Patel, for the help in organizing this special issue.}, number={1}, journal={JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME}, author={Vadasz, Peter and Kuznetsov, Andrey V.}, year={2011}, month={Jan} }
@article{kuznetsov_nield_2011, title={THE EFFECT OF LOCAL THERMAL NONEQUILIBRIUM ON THE ONSET OF CONVECTION IN A POROUS MEDIUM LAYER SATURATED BY A NANOFLUID: BRINKMAN MODEL}, volume={14}, ISSN={["1934-0508"]}, DOI={10.1615/jpormedia.v14.i4.10}, abstractNote={The onset of convection in a horizontal layer of a porous medium saturated by a nanofluid is studied analytically. The model used for the nanofluid incorporates the effects of Brownian motion and thermophoresis. For the porous medium the Brinkman model is employed. Three cases of free-free, rigid-rigid, and rigid-free boundaries are considered. The effect of local thermal nonequilibrium between the particle, fluid, and solid-matrix phases is investigated using a three-temperature model. The analysis reveals that in some circumstances the effect of local thermal nonequilibrium (LTNE) can be significant, but for a typical dilute nanofluid (with large Lewis number and with small particle-to-fluid heat capacity ratio) the effect is small.}, number={4}, journal={JOURNAL OF POROUS MEDIA}, author={Kuznetsov, A. V. and Nield, D. A.}, year={2011}, pages={285–293} }
@article{nield_kuznetsov_2011, title={The Cheng-Minkowycz problem for natural convection about a vertical plate embedded in a tridisperse porous medium}, volume={54}, ISSN={["0017-9310"]}, DOI={10.1016/j.ijheatmasstransfer.2011.03.037}, abstractNote={The classical Cheng–Minkowycz study of convection past a vertical plate embedded in a porous medium has been extended to the case of a tridisperse porous medium (TDPM). The boundary-layer analysis leads to expressions for the velocity and temperature fields in terms of two geometrical parameters, two inter-phase momentum transfer parameters, two thermal diffusivity ratios, two permeability ratios, two thermal conductivity ratios, and two inter-phase heat transfer parameters. For the leading edge region, and for an inner layer, a similarity solution is obtained. This involves the first eight parameters, each of which is a characteristic of the TDPM.}, number={15-16}, journal={INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2011}, month={Jul}, pages={3485–3493} }
@article{nield_kuznetsov_2011, title={The Cheng-Minkowycz problem for the double-diffusive natural convective boundary layer flow in a porous medium saturated by a nanofluid}, volume={54}, ISSN={["1879-2189"]}, DOI={10.1016/j.ijheatmasstransfer.2010.09.034}, abstractNote={The paper presents an analytical treatment of double-diffusive nanofluid convection in a porous medium. The problem treated is natural convection past a vertical plate when the base fluid of the nanofluid is itself a binary fluid such as salty water. The model used for the nanofluid incorporates the effects of Brownian motion and thermophoresis, while the Darcy model is used for the porous medium. In addition the thermal energy equations include regular diffusion and cross-diffusion terms. A similarity solution is presented.}, number={1-3}, journal={INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2011}, month={Jan}, pages={374–378} }
@article{nield_kuznetsov_2011, title={The Effect of Vertical Throughflow on Thermal Instability in a Porous Medium Layer Saturated by a Nanofluid}, volume={87}, ISSN={["0169-3913"]}, DOI={10.1007/s11242-011-9717-x}, number={3}, journal={TRANSPORT IN POROUS MEDIA}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2011}, month={Apr}, pages={765–775} }
@article{nield_kuznetsov_2011, title={The Effect of Vertical Throughflow on the Onset of Convection in a Porous Medium in a Rectangular Box}, volume={90}, ISSN={["1573-1634"]}, DOI={10.1007/s11242-011-9828-4}, number={3}, journal={TRANSPORT IN POROUS MEDIA}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2011}, month={Dec}, pages={993–1000} }
@article{kuznetsov_nield_2011, title={The Effects of Combined Horizontal and Vertical Heterogeneity on the Onset of Convection in a Porous Medium with Vertical Throughflow}, volume={90}, ISSN={["1573-1634"]}, DOI={10.1007/s11242-011-9795-9}, number={2}, journal={TRANSPORT IN POROUS MEDIA}, author={Kuznetsov, A. V. and Nield, D. A.}, year={2011}, month={Nov}, pages={465–478} }
@article{nield_kuznetsov_2011, title={The Onset of Convection in a Heterogeneous Porous Medium with Vertical Throughflow}, volume={88}, ISSN={["0169-3913"]}, DOI={10.1007/s11242-011-9742-9}, number={2}, journal={TRANSPORT IN POROUS MEDIA}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2011}, month={Jun}, pages={347–355} }
@article{kuznetsov_nield_simmons_2011, title={The Onset of Convection in a Strongly Heterogeneous Porous Medium with Transient Temperature Profile}, volume={86}, ISSN={["1573-1634"]}, DOI={10.1007/s11242-010-9657-x}, number={3}, journal={TRANSPORT IN POROUS MEDIA}, author={Kuznetsov, A. V. and Nield, D. A. and Simmons, Craig T.}, year={2011}, month={Feb}, pages={851–865} }
@article{nield_kuznetsov_2011, title={The effects of combined horizontal and vertical heterogeneity on the onset of convection in a porous medium with horizontal throughflow}, volume={54}, ISSN={["1879-2189"]}, DOI={10.1016/j.ijheatmasstransfer.2011.07.019}, abstractNote={The effects of hydrodynamic and thermal heterogeneity, for the case of variation in both the horizontal and vertical directions, on the onset of convection in a horizontal layer of a saturated porous medium uniformly heated from below, with horizontal throughflow, are studied analytically for the case of weak heterogeneity. It is found that the horizontal throughflow has no effect on the stability of the longitudinal modes but it does affect the stability of the transverse modes. When the permeability decreases in the direction of the throughflow the transverse modes are stabilized (and so the longitudinal ones are favored). When the permeability increases in the direction of the throughflow a small amount of throughflow may destabilize the transverse modes and so destabilize the layer as a whole.}, number={25-26}, journal={INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2011}, month={Dec}, pages={5595–5601} }
@article{kuznetsov_nield_2011, title={The onset of convection in a tridisperse porous medium}, volume={54}, ISSN={["0017-9310"]}, DOI={10.1016/j.ijheatmasstransfer.2011.04.021}, abstractNote={This paper develops a theory of mass, momentum, and heat transfer in a tridisperse porous medium. Coupling between three different scales present in this medium is accounted for by introducing momentum and interphase heat transfer coupling coefficients. The developed theory is then applied to solve the classical Rayleigh–Bénard problem, for the onset of convection in a horizontal layer uniformly heated from below, for this new type of a porous medium. The formulation uses the Darcy law, which now results in three different filtration velocities in three porosity scales present in this medium. The linear stability analysis leads to an expression for the critical Rayleigh number as a function of three volume fractions, two permeability ratios, two thermal capacity ratios, two thermal conductivity ratios, two inter-phase heat transfer parameters and two inter-phase momentum transfer parameters. The dependence of the critical Rayleigh number on these parameters is investigated.}, number={15-16}, journal={INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER}, author={Kuznetsov, A. V. and Nield, D. A.}, year={2011}, month={Jul}, pages={3120–3127} }
@article{nield_kuznetsov_2011, title={The onset of double-diffusive convection in a nanofluid layer}, volume={32}, ISSN={["1879-2278"]}, DOI={10.1016/j.ijheatfluidflow.2011.03.010}, abstractNote={The onset of double-diffusive convection in a horizontal layer of a nanofluid is studied analytically. The model used for the nanofluid incorporates the effects of Brownian motion and thermophoresis. In addition the thermal energy equations include regular diffusion and cross-diffusion terms. The stability boundaries for both non-oscillatory and oscillatory cases have been approximated by simple analytical expressions. Physical significance of the obtained results is discussed.}, number={4}, journal={INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2011}, month={Aug}, pages={771–776} }
@article{barletta_celli_kuznetsov_2011, title={Transverse Heterogeneity Effects in the Dissipation-Induced Instability of a Horizontal Porous Layer}, volume={133}, ISSN={["0022-1481"]}, DOI={10.1115/1.4004371}, abstractNote={The linear stability of a parallel flow in a heterogeneous porous channel is analyzed by means of the Darcy law and the Oberbeck–Boussinesq approximation. The basic velocity and temperature distributions are influenced by the effect of the viscous dissipation, as well as, by the boundary conditions. A horizontal porous layer bounded by impermeable and infinitely wide walls is considered. The lower boundary is assumed to be thermally insulated, while the upper boundary is assumed to be isothermal. A transverse heterogeneity for the permeability and for the thermal conductivity is taken into account. The main task of this work is to investigate the role of this heterogeneity in changing the threshold for the onset of instability. A linear stability analysis by means of the normal modes method is performed. The onset of instability against oblique rolls is studied. The eigenvalue problem is solved numerically.}, number={12}, journal={JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME}, author={Barletta, A. and Celli, M. and Kuznetsov, A. V.}, year={2011}, month={Dec} }
@article{avramenko_kuznetsov_2010, title={Bio-thermal convection caused by combined effects of swimming of oxytactic bacteria and inclined temperature gradient in a shallow fluid layer}, volume={20}, ISSN={["1758-6585"]}, DOI={10.1108/09615531011016939}, abstractNote={PurposeThe aim of this paper is to investigate the onset of bio‐thermal convection in a shallow fluid layer; the convection is thus driven by the combined effect of swimming of oxytactic microorganisms and inclined temperature gradient.}, number={2}, journal={INTERNATIONAL JOURNAL OF NUMERICAL METHODS FOR HEAT & FLUID FLOW}, author={Avramenko, A. A. and Kuznetsov, A. V.}, year={2010}, pages={157–173} }
@article{geng_zheng_kuznetsov_roberts_paxson_2010, title={Comparison Between Numerically Simulated and Experimentally Measured Flowfield Quantities Behind a Pulsejet}, volume={84}, ISSN={["1573-1987"]}, DOI={10.1007/s10494-010-9247-6}, abstractNote={Pulsed combustion is receiving renewed interest as a potential route to higher performance in air breathing propulsion and ground based power generation systems. Pulsejets offer a simple experimental device with which to study unsteady combustion phenomena and validate simulations. Previous computational fluid dynamics (CFD) simulations focused primarily on pulsejet combustion and exhaust processes. This paper describes a new inlet sub-model which simulates the fluidic and mechanical operation of a valved pulsejet head. The governing equations for this sub-model are described. Sub-model validation is provided through comparisons of simulated and experimentally measured reed valve motion, and time averaged inlet mass flow rate. The updated pulsejet simulation, with the inlet sub-model implemented, is validated through comparison with experimentally measured combustion chamber pressure, inlet mass flow rate, operational frequency, and thrust. Additionally, the simulated pulsejet exhaust flowfield, which is dominated by a starting vortex ring, is compared with particle imaging velocimetry (PIV) measurements on the bases of velocity, vorticity, and vortex location. The results show good agreement between simulated and experimental data. The inlet sub-model is shown to be critical for the successful modeling of pulsejet operation. This sub-model correctly predicts both the inlet mass flow rate and its phase relationship with the combustion chamber pressure. As a result, the predicted pulsejet thrust agrees very well with experimental data.}, number={4}, journal={FLOW TURBULENCE AND COMBUSTION}, author={Geng, Tao and Zheng, Fei and Kuznetsov, Andrey V. and Roberts, William L. and Paxson, Daniel E.}, year={2010}, month={Jun}, pages={653–667} }
@article{kuznetsov_2010, title={Comparison of active transport in neuronal axons and dendrites}, volume={228}, ISSN={["0025-5564"]}, DOI={10.1016/j.mbs.2010.10.003}, abstractNote={This paper presents a theoretical study, based on modified Smith–Simmons equations, that compares transport of intracellular organelles in two different neurite outgrowths, dendrites and axons. It is demonstrated that the difference in microtubule polarity orientations in dendrites and axons has significant implications on motor-assisted transport in these neurite outgrowths. The developed approach presents a qualitative theoretical basis for understanding important questions such as why axons exhibit almost an unlimited grows potential in vitro while dendrites remain relatively short. It is shown that the difference in a microtubule polarity arrangement between axons and dendrites may be a regulatory mechanism for limiting dendritic growth. Other biological implications of the developed theory as well as other possible reasons for the difference in microtubule structure between axons and dendrites are discussed.}, number={2}, journal={MATHEMATICAL BIOSCIENCES}, author={Kuznetsov, A. V.}, year={2010}, month={Dec}, pages={195–202} }
@article{kuznetsov_nield_2010, title={Corrigendum to ‘Forced Convection with Slip-Flow in a Channel Occupied by a Hyperporous Medium Saturated by a Rarefied Gas’, Transport in Porous Media, 64, 161–170, 2006, and ‘Thermally Developing Forced Convection in a Porous Medium Occupied by a Rarefied Gas: Parallel Plate Channel or Circular Tube with Walls at Constant Heat Flux’, Transport in Porous Media, 76, 345–362, 2009}, volume={85}, ISSN={0169-3913 1573-1634}, url={http://dx.doi.org/10.1007/s11242-010-9654-0}, DOI={10.1007/s11242-010-9654-0}, number={2}, journal={Transport in Porous Media}, publisher={Springer Science and Business Media LLC}, author={Kuznetsov, A. V. and Nield, D. A.}, year={2010}, month={Sep}, pages={657–658} }
@article{kuznetsov_nield_2010, title={Effect of Local Thermal Non-equilibrium on the Onset of Convection in a Porous Medium Layer Saturated by a Nanofluid}, volume={83}, ISSN={["0169-3913"]}, DOI={10.1007/s11242-009-9452-8}, number={2}, journal={TRANSPORT IN POROUS MEDIA}, author={Kuznetsov, A. V. and Nield, D. A.}, year={2010}, month={Jun}, pages={425–436} }
@article{kuznetsov_avramenko_blinov_2010, title={Effect of diffusion on slowing the velocity of a bell-shaped wave in slow axonal transport}, volume={37}, ISSN={["0735-1933"]}, DOI={10.1016/j.icheatmasstransfer.2010.05.010}, abstractNote={This paper models transport of organelles by slow axonal transport utilizing the stop-and-go hypothesis, which postulates that in slow axonal transport the motion of organelles does not occur continuously; instead, organelles move along microtubules (MTs) alternating between short periods of rapid movement, short on-track pauses, and prolonged off-track pauses, when they temporarily disengage from MTs. The model considers six kinetic states of organelles: anterogradely moving state, retrogradely moving state, anterogradely pausing state, retrogradely pausing state, off-track anterograde state, and off-track retrograde state. The paper extends the existing model of slow axonal transport by accounting for the diffusivity of off-track organelles and investigates how the diffusivity of these organelles affects the amplitude, velocity, and rate of change of the variance of the bell-shaped wave which describes the probability density function (PDF) corresponding to the ratio of the chance of finding an organelle within an infinitesimal interval in the axon to the length of this interval. The velocity of this wave characterizes the average effective velocity (calculated including pauses) of an organelle in slow axonal transport while the rate of change of the variance characterizes the rate of spread of the initial packet of organelles transported in the axon. The goal of this research is not only to develop a more accurate transport model, but also to understand fundamentally the effects of diffusion on slow axonal transport. It is demonstrated that diffusion decreases the amplitude of the wave and increases the rate of its spread but does not affect wave's velocity.}, number={7}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Kuznetsov, A. V. and Avramenko, A. A. and Blinov, D. G.}, year={2010}, month={Aug}, pages={770–774} }
@article{simmons_kuznetsov_nield_2010, title={Effect of strong heterogeneity on the onset of convection in a porous medium: Importance of spatial dimensionality and geologic controls}, volume={46}, ISSN={["0043-1397"]}, DOI={10.1029/2009wr008606}, abstractNote={The effect of strong heterogeneity on the onset of convection induced by a vertical density gradient in a saturated heterogeneous porous medium governed by Darcy's law is investigated. A computer package has been developed to study the applicability of an average Rayleigh number as a criterion for the onset of convection in strongly heterogeneous geologic media. The heterogeneous geologic media have been described using random spatial functions for the permeability field which are lognormally distributed and spatially correlated. Both isotropic and anisotropic correlation lengths within the geologic structure are considered. This paper presents the first 3D theoretical treatment of the conditions for the onset of convection (Rayleigh stability criteria) in strongly heterogeneous porous media. We elucidate the critical role that spatial dimensionality (2D versus 3D flow) plays in controlling convection processes and stability criteria. Our results quantitatively demonstrate for the first time that spatial dimensionality is a dominant control on the onset of convection in a strongly heterogeneous geologic medium. Unbounded Rayleigh number behavior is observed in 3D. This leads to the important new conclusion that a Rayleigh number (based on mean quantities) is unlikely to be a valid predictor for the onset of convection in 3D strongly heterogeneous porous media. Furthermore, we systematically and quantitatively demonstrate that the onset of convection in a heterogeneous geologic medium is highly sensitive to changes in the standard deviation of the lognormal permeability field, moderately sensitive to changes in the level of correlation length, and relatively insensitive to the anisotropy of correlation length.}, journal={WATER RESOURCES RESEARCH}, author={Simmons, Craig T. and Kuznetsov, A. V. and Nield, D. A.}, year={2010}, month={Sep} }
@article{kuznetsov_2010, title={Effect of the degree of polar mismatching on traffic jam formation in fast axonal transport}, volume={13}, ISSN={["1476-8259"]}, DOI={10.1080/10255840903505154}, abstractNote={This paper simulates an axon with a region of reversed microtubule (MT) polarity, and investigates how the degree of polar mismatching in this region affects the formation of organelle traps in the axon. The model is based on modified Smith–Simmons equations governing molecular-motor-assisted transport in neurons. It is established that the structure that develops as a result of a region with disoriented MTs consists of two organelle traps, the trap to the left of this region accumulates plus-end-oriented organelles and the trap to the right of this region accumulates minus-end-oriented organelles. The presence of such a structure is shown to inhibit the transport of organelles down the axon. The degree by which the transport of organelles is inhibited depends on the degree of polar mismatching of MTs in the region between MT traps. Four cases with a different degree of polar mismatching are investigated.}, number={6}, journal={COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING}, author={Kuznetsov, A. V.}, year={2010}, pages={711–722} }
@article{kuznetsov_2010, title={Effect of the width of regions with severed microtubules on transport of organelles down the axon}, volume={37}, ISSN={["0735-1933"]}, DOI={10.1016/j.icheatmasstransfer.2009.12.008}, abstractNote={This paper investigates the effects of structural changes in the microtubule system on traffic jam formation in fast axonal transport and on inhibiting transport of organelles down the axon. Understanding this process is important for understanding the underlying reasons for many neurodegenerative diseases, such as Alzheimer's disease. In particular, the effect of the width of regions with severed microtubules (also called organelle traps) on the amount of organelles delivered to the synapse of the axon is investigated. Three cases with a different degree of microtubule polar mismatching in the microtubule swirl region are investigated. It is demonstrated that in all three cases increasing the width of organelle trap regions significantly decreases the flux of organelles down the axon compared to that in a healthy axon, in which case organelle traps are absent.}, number={5}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Kuznetsov, A. V.}, year={2010}, month={May}, pages={443–448} }
@article{kuznetsov_2010, title={Effect of vesicle traps on traffic jam formation in fast axonal transport}, volume={226}, ISSN={["0025-5564"]}, DOI={10.1016/j.mbs.2010.05.003}, abstractNote={The purpose of this paper is to develop a model for simulation of the formation of organelle traps in fast axonal transport. Such traps may form in the regions of microtubule polar mismatching. Depending on the orientation of microtubules pointing toward the trap region, these traps can accumulate either plus-end or minus-end oriented vesicles. The model predicts that the maximum concentrations of organelles occur at the boundaries of the trap regions; the overall concentration of organelles in the axon with traps is greatly increased compared to that in a healthy axon, which is expected to contribute to mechanical damages of the axon. The organelle traps induce hindrance to organelle transport down the axon; the total organelle flux down the axon with traps is found to be significantly reduced compared to that in a healthy axon.}, number={2}, journal={MATHEMATICAL BIOSCIENCES}, author={Kuznetsov, A. V.}, year={2010}, month={Aug}, pages={147–155} }
@article{kuznetsov_2010, title={Equations describing molecular-motor-assisted transport in dendrites with a non-uniform cross-sectional area}, volume={37}, ISSN={["1879-0178"]}, DOI={10.1016/j.icheatmasstransfer.2010.05.020}, abstractNote={The purpose of this paper is to develop new transport equations describing transport of intracellular organelles by a combined effect of diffusion and molecular-motor-driven transport in dendrites of neuron cells that have a non-uniform cross-sectional area which depends on the distance from the neuron soma. The obtained equations are solved numerically for two types of microtubule (MT) orientations that are experimentally found in dendrites. In one type of dendrites, which is found in cultured rat hippocampal neurons, MTs have a mixed polarity orientation while in the second type, which is found in Drosophila neurons, MTs have the minus-end-out polarity orientation. Simulations show important differences in organelle transport in these two types of dendrites. The conclusion is that the MT orientation has a profound effect on the total rate of organelle transfer toward the growth cone of a dendrite and consequently determines its growth potential and its growth rate.}, number={7}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Kuznetsov, A. V.}, year={2010}, month={Aug}, pages={725–730} }
@article{nield_kuznetsov_2010, title={FORCED CONVECTION WITH PHASE-LAGGED OSCILLATORY COUNTERFLOW IN A SATURATED POROUS CHANNEL}, volume={13}, ISSN={["1934-0508"]}, DOI={10.1615/jpormedia.v13.i7.20}, abstractNote={An analytical solution is obtained for forced convection in a parallel plate channel occupied by a layered saturated porous medium with counterflow produced by pressure gradients oscillating in time about a zero mean. The case of asymmetrical constant heat-flux boundary conditions is considered, and the Brinkman model is employed for the porous medium. Expressions for the velocity, temperature distribution, and Nusselt number are obtained. It is found that oscillation about a zero mean does not cause the Nusselt number to oscillate, but in general its value is dependent on the frequency of oscillation, the variation becoming significant at large values of the frequency.}, number={7}, journal={JOURNAL OF POROUS MEDIA}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2010}, pages={601–611} }
@article{kuznetsov_nield_2010, title={Forced convection in a channel partly occupied by a bidisperse porous medium: Asymmetric case}, volume={53}, ISSN={["0017-9310"]}, DOI={10.1016/j.ijheatmasstransfer.2010.07.046}, abstractNote={This paper presents an analytic investigation of forced convection in parallel-plate channel partly occupied by a bidisperse porous medium and partly by a fluid clear of solid material, the distribution being asymmetrical. The walls of the channel are subject to an uniform heat flux; the flow is assumed to be hydrodynamically and thermally fully developed. The layer of a bidisperse porous medium is attached to one of the channel walls; it is modeled utilizing a two-velocity two-temperature formulation using Darcy's law. The Beavers–Joseph boundary condition is employed at the bidisperse porous medium/clear fluid interface. The dependences of the Nusselt number on a conductivity ratio, a velocity ratio, a volume fraction, internal heat exchange parameter, and the position of the porous-fluid interface are investigated. Both cases of symmetric and asymmetric heating are investigated, which is specified by the asymmetry heating parameter introduced here. For the case of asymmetric heating, a singular behavior of the Nusselt number is found and explained.}, number={23-24}, journal={INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER}, author={Kuznetsov, A. V. and Nield, D. A.}, year={2010}, month={Nov}, pages={5167–5175} }
@article{nield_kuznetsov_2010, title={Forced convection in cellular porous materials: Effect of temperature-dependent conductivity arising from radiative transfer}, volume={53}, ISSN={["1879-2189"]}, DOI={10.1016/j.ijheatmasstransfer.2010.02.041}, abstractNote={Forced convection in a channel occupied by a saturated cellular porous medium is investigated. The problem is formulated as a combined conductive–convective–radiative problem in which radiative heat transfer is treated as a diffusion process. The problem is relevant to cellular foams formed from plastics, ceramics and metals. Special cases in which radiative conductivity is modeled as a power function of temperature as well as the Stefan-Boltzmann case are investigated. Analytical and numerical solutions are obtained; Darcy and clear fluid limits are also studied.}, number={13-14}, journal={INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2010}, month={Jun}, pages={2680–2684} }
@article{kuznetsov_avramenko_blinov_2010, title={MODELING TRAFFIC JAMS IN SLOW AXONAL TRANSPORT}, volume={10}, ISSN={["1793-6810"]}, DOI={10.1142/s0219519410003502}, abstractNote={The purpose of this paper is to develop a model capable of simulating traffic jams in slow axonal transport. Slowing of slow axonal transport is an early sign of some neurodegenerative diseases. Axonal swellings observed near the end stage of such diseases may be an indication of traffic jams developing in axons that cause the slowing down of slow axonal transport. Traffic jams may result from misregulation of microtubule-associated proteins caused by an imbalance in intracellular signaling or by mutations of these proteins. This misregulation leads to a decay of microtubule tracks in axons, effectively reducing the number of "railway tracks" available for molecular-motor-assisted transport of intracellular organelles. In this paper, the decay of microtubule tracks is modeled by a reduction of the number density of microtubules in the central part of the axon. Simulation results indicate that the model predicts the build-up of the bell-shaped concentration wave, as the wave approaches the bottleneck (blockage) region. This increase in concentration will likely plug the bottleneck region resulting in a traffic jam that would hinder the slow axonal transport.}, number={3}, journal={JOURNAL OF MECHANICS IN MEDICINE AND BIOLOGY}, author={Kuznetsov, A. V. and Avramenko, A. A. and Blinov, D. G.}, year={2010}, month={Sep}, pages={445–465} }
@article{wu_kuznetsov_jasper_2010, title={Modeling of particle trajectories in an electrostatically charged channel}, volume={22}, ISSN={["1070-6631"]}, DOI={10.1063/1.3369004}, abstractNote={Modeling and analyses of filtration efficiency in electrostatically charged monolith filters are important for evaluating and designing this class of filters. Unlike traditional fibrous filters which comprise external flow around a fiber, monolith filters are modeled as internal flow through small channels. Analogous to single fiber theory for external flows, single channel theory is used to analyze basic fluid mechanics in monolith filters and predict filtration efficiencies. The model incorporates three forces: hydrodynamic forces, electrostatic forces, and Brownian motion. Fluid velocity within the channels is calculated by using an analytical solution for circular channel flow, within which the slip boundary condition is considered because of small length scales. This velocity field is then used to evaluate the drag force on the particle according to Stokes’s law. For this model, a one-way coupling between the fluid flow and the particle motion is assumed due to the fact that the relaxation time for the particles simulated in this paper is very small compared to the time the particles spend in the channel. The electrostatic field is computed assuming a uniform charge distribution on the inner surface of a cylindrical channel of finite length. Using a Monte Carlo simulation, particles are randomly injected into a single channel to determine the filtration efficiency.}, number={4}, journal={PHYSICS OF FLUIDS}, publisher={AIP Publishing}, author={Wu, Mengbai and Kuznetsov, Andrey V. and Jasper, Warren J.}, year={2010}, month={Apr} }
@article{kuznetsov_2010, title={Modeling organelle transport in branching dendrites with a variable cross-sectional area}, volume={36}, DOI={10.1007/s10867-010-9191-7}, abstractNote={The purpose of this paper is to develop a method for calculating organelle transport in dendrites with a non-uniform cross-sectional area that depends on the distance from the neuron soma. The model is based on modified Smith-Simmons equations governing molecular motor-assisted organelle transport. The developed method is then applied to simulating organelle transport in branching dendrites with two particular microtubule (MT) orientations reported from experiments. It is found that the rate of organelle transport toward a dendrite's growth cone heavily depends on the MT orientation, and since there is experimental evidence that the MT orientation in a particular region of a dendrite may depend on the dendrite's developmental stage, the obtained results suggest that a rearrangement of the MT structure may depend on the amount of organelles needed at the growth cone.}, number={4}, journal={Journal of Biological Physics}, author={Kuznetsov, A. V.}, year={2010}, pages={385–403} }
@article{kuznetsov_avramenko_blinov_2010, title={Modeling the effect of a microtubule swirl on fast axonal transport}, volume={37}, ISSN={["1879-0178"]}, DOI={10.1016/j.icheatmasstransfer.2009.11.005}, abstractNote={Many neurodegenerative diseases, such as Alzheimer's disease, are linked to swellings occurring in the long arms of neurons. Many scientists believe that these swellings result from traffic jams caused by the failure of the intracellular machinery responsible for fast axonal transport; such traffic jam can plug an axon and prevent the sufficient amount of organelles to be delivered toward the synapse of the axon. One possible mechanistic explanation of the formation of traffic jams in axons induced by overexpression of tau protein is based on the hypothesis that the traffic jam is caused not by the failure of molecular motors to transport organelles along individual microtubules but rather by the disruption of the microtubule system in an axon, by the formation of a swirl of disoriented microtubules at a certain location in the axon. This paper develops a model for investigating the effect of a microtubule swirl, as well as the effect of reversing polarity of a microtubule segment in the swirl region, on fast axonal transport.}, number={3}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Kuznetsov, A. V. and Avramenko, A. A. and Blinov, D. G.}, year={2010}, month={Mar}, pages={234–238} }
@article{kuznetsov_nield_2010, title={Natural convective boundary-layer flow of a nanofluid past a vertical plate}, volume={49}, ISSN={["1778-4166"]}, DOI={10.1016/j.ijthermalsci.2009.07.015}, abstractNote={The natural convective boundary-layer flow of a nanofluid past a vertical plate is studied analytically. The model used for the nanofluid incorporates the effects of Brownian motion and thermophoresis. A similarity solution is presented. This solution depends on a Lewis number Le, a buoyancy-ratio number Nr, a Brownian motion number Nb, and a thermophoresis number Nt. For various values of Pr and Le, the variation of the reduced Nusselt number with Nr, Nb and Nt is expressed by correlation formulas. It was found that the reduced Nusselt number is a decreasing function of each of Nr, Nb and Nt.}, number={2}, journal={INTERNATIONAL JOURNAL OF THERMAL SCIENCES}, author={Kuznetsov, A. V. and Nield, D. A.}, year={2010}, month={Feb}, pages={243–247} }
@article{kuznetsov_nield_2010, title={The Cheng-Minkowycz problem for cellular porous materials: Effect of temperature-dependent conductivity arising from radiative transfer}, volume={53}, ISSN={["0017-9310"]}, DOI={10.1016/j.ijheatmasstransfer.2010.02.042}, abstractNote={Abstract The Cheng–Minkowycz problem involving natural convection boundary layer flow adjacent to a vertical wall in a saturated cellular porous medium subject to Darcy’s law is investigated. The problem is formulated as a combined conductive–convective–radiative problem in which radiative heat transfer is treated as a diffusion process. The problem is relevant to cellular foams formed from plastics, ceramics, and metals. The situation in which radiative conductivity is modeled utilizing the Stefan–Boltzmann law is investigated. If the temperature variation parameter, Tr, is equal to zero, the classical Cheng–Minkowycz solution is recovered. For a non-zero value of Tr the results show that the reduced Rayleigh number is a decreasing function of Tr.}, number={13-14}, journal={INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER}, author={Kuznetsov, A. V. and Nield, D. A.}, year={2010}, month={Jun}, pages={2676–2679} }
@article{nield_kuznetsov_simmons_2010, title={The Effect of Strong Heterogeneity on the Onset of Convection in a Porous Medium: 2D/3D Localization and Spatially Correlated Random Permeability Fields}, volume={83}, ISSN={["1573-1634"]}, DOI={10.1007/s11242-009-9455-5}, number={3}, journal={TRANSPORT IN POROUS MEDIA}, author={Nield, D. A. and Kuznetsov, A. V. and Simmons, Craig T.}, year={2010}, month={Jul}, pages={465–477} }
@article{kuznetsov_nield_simmons_2010, title={The Effect of Strong Heterogeneity on the Onset of Convection in a Porous Medium: Periodic and Localized Variation}, volume={81}, ISSN={["1573-1634"]}, DOI={10.1007/s11242-009-9390-5}, number={1}, journal={TRANSPORT IN POROUS MEDIA}, author={Kuznetsov, A. V. and Nield, D. A. and Simmons, Craig T.}, year={2010}, month={Jan}, pages={123–139} }
@article{nield_kuznetsov_2010, title={The Onset of Convection in a Heterogeneous Porous Medium with Transient Temperature Profile}, volume={85}, ISSN={["1573-1634"]}, DOI={10.1007/s11242-010-9586-8}, number={3}, journal={TRANSPORT IN POROUS MEDIA}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2010}, month={Dec}, pages={691–702} }
@article{nield_kuznetsov_2010, title={The Onset of Convection in a Layer of Cellular Porous Material: Effect of Temperature-Dependent Conductivity Arising From Radiative Transfer}, volume={132}, ISSN={["0022-1481"]}, DOI={10.1115/1.4001125}, abstractNote={The onset of convection in a horizontal layer of a cellular porous material heated from below is investigated. The problem is formulated as a combined conductive-convective-radiative problem in which radiative heat transfer is treated as a diffusion process. The problem is relevant to cellular foams formed from plastics, ceramics, and metals. It is shown that the variation of conductivity with temperature above that of the cold boundary leads to an increase in the critical Rayleigh number (based on the conductivity of the fluid at that boundary temperature) and an increase in the critical wave number. On the other hand, the critical Rayleigh number based on the conductivity at the mean temperature decreases with increase in the thermal variation parameter if the radiative contribution to the effective conductivity is sufficiently large compared with the nonradiative component.}, number={7}, journal={JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2010}, month={Jul} }
@article{kuznetsov_nield_2010, title={The Onset of Double-Diffusive Nanofluid Convection in a Layer of a Saturated Porous Medium}, volume={85}, ISSN={["0169-3913"]}, DOI={10.1007/s11242-010-9600-1}, number={3}, journal={TRANSPORT IN POROUS MEDIA}, author={Kuznetsov, A. V. and Nield, D. A.}, year={2010}, month={Dec}, pages={941–951} }
@article{nield_kuznetsov_2010, title={The effect of local thermal nonequilibrium on the onset of convection in a nanofluid}, volume={132}, DOI={10.1115/1.4000474}, abstractNote={The onset of convection in a horizontal layer of a nanofluid is studied analytically. The model used for the nanofluid incorporates the effects of Brownian motion and thermophoresis, and allows for local thermal nonequilibrium (LTNE) between the particle and fluid phases. The analysis reveals that in some circumstances, the effect of LTNE can be significant, but for a typical dilute nanofluid (with large Lewis number and with small particle-to-fluid heat capacity ratio), the effect is small.}, number={5}, journal={Journal of Heat Transfer}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2010} }
@article{avramenko_kuznetsov_2010, title={The onset of bio-thermal convection in a suspension of gyrotactic microorganisms in a fluid layer with an inclined temperature gradient}, volume={20}, ISSN={["1758-6585"]}, DOI={10.1108/09615531011008154}, abstractNote={PurposeThe purpose of this paper is to investigate a combined bioconvection and thermal instability problem in a horizontal layer of finite depth with a basic temperature gradient inclined to the vertical. The basic flow, driven by the horizontal component of temperature gradient, is the Hadley circulation, which becomes unstable when the vertical temperature difference and density stratification induced by upswimming of microorganisms that are heavier than water become sufficiently large.}, number={1}, journal={INTERNATIONAL JOURNAL OF NUMERICAL METHODS FOR HEAT & FLUID FLOW}, author={Avramenko, A. A. and Kuznetsov, A. V.}, year={2010}, pages={111–129} }
@article{nield_kuznetsov_2010, title={The onset of convection in a horizontal nanofluid layer of finite depth}, volume={29}, ISSN={["1873-7390"]}, DOI={10.1016/j.euromechflu.2010.02.003}, abstractNote={This paper presents a linear stability analysis for the onset of natural convection in a horizontal nanofluid layer. The employed model incorporates the effects of Brownian motion and thermophoresis. Both monotonic and oscillatory convection for free–free, rigid–rigid, and rigid–free boundaries are investigated. The oscillatory instability is possible when nanoparticles concentrate near the bottom of the layer, so that the density gradient caused by such a bottom-heavy nanoparticle distribution competes with the density variation caused by heating from the bottom. It is established that the instability is almost purely a phenomenon due to buoyancy coupled with the conservation of nanoparticles. It is independent of the contributions of Brownian motion and thermophoresis to the thermal energy equation. Rather, the Brownian motion and thermophoresis enter to produce their effects directly into the equation expressing the conservation of nanoparticles so that the temperature and the particle density are coupled in a particular way, and that results in the thermal and concentration buoyancy effects being coupled in the same way.}, number={3}, journal={EUROPEAN JOURNAL OF MECHANICS B-FLUIDS}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2010}, pages={217–223} }
@article{kuznetsov_2010, title={The onset of nanofluid bioconvection in a suspension containing both nanoparticles and gyrotactic microorganisms}, volume={37}, ISSN={["1879-0178"]}, DOI={10.1016/j.icheatmasstransfer.2010.08.015}, abstractNote={The purpose of this paper is to study the onset of bioconvection in a horizontal layer filled with a nanofluid that also contains gyrotactic microorganisms. The idea is to use microorganisms to induce or enhance convection in a nanofluid. A linear instability analysis is used to solve this problem. A Galerkin method is utilized to obtain an analytical solution for the critical Rayleigh number for the non-oscillatory situation. As in the case of a regular nanofluid (without the microorganisms), the presence of nanoparticles can either reduce or increase the value of the critical Rayleigh number, depending on whether the basic nanoparticle distribution is top-heavy or bottom-heavy. In contrast, the effect of gyrotactic microorganisms is always destabilizing.}, number={10}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Kuznetsov, A. V.}, year={2010}, month={Dec}, pages={1421–1425} }
@article{kuznetsov_nield_2010, title={Thermal Instability in a Porous Medium Layer Saturated by a Nanofluid: Brinkman Model}, volume={81}, ISSN={["1573-1634"]}, DOI={10.1007/s11242-009-9413-2}, number={3}, journal={TRANSPORT IN POROUS MEDIA}, author={Kuznetsov, A. V. and Nield, D. A.}, year={2010}, month={Feb}, pages={409–422} }
@article{kuznetsov_avramenko_2009, title={A macroscopic model of traffic jams in axons}, volume={218}, ISSN={["1879-3134"]}, DOI={10.1016/j.mbs.2009.01.005}, abstractNote={The purpose of this paper is to develop a minimal macroscopic model capable of explaining the formation of traffic jams in fast axonal transport. The model accounts for the decrease of the number density of positively (and negatively) oriented microtubules near the location of the traffic jam due to formation of microtubule swirls; the model also accounts for the reduction of the effective velocity of organelle transport in the traffic jam region due to organelles falling off microtubule tracks more often in the swirl region. The model is based on molecular-motor-assisted transport equations and the hydrodynamic model of traffic jams in highway traffic. Parametric analyses of the model's predictions for various values of viscosity of the traffic flow, variance of the velocity distribution, diffusivity of microtubule-bound and free organelles, rate constants for binding to and detachment from microtubules, relaxation time, and average motor velocities of the retrograde and anterograde transport, are carried out.}, number={2}, journal={MATHEMATICAL BIOSCIENCES}, author={Kuznetsov, A. V. and Avramenko, A. A.}, year={2009}, month={Apr}, pages={142–152} }
@article{kuznetsov_avramenko_2009, title={A minimal hydrodynamic model for a traffic jam in an axon}, volume={36}, ISSN={["1879-0178"]}, DOI={10.1016/j.icheatmasstransfer.2008.09.004}, abstractNote={Traffic jams in long processes of nerve cells (neurons) are linked to such neurodegenerative diseases as Alzheimer's disease and Down syndrome. These traffic jams cause swellings in the neurons' processes that accumulate large amounts of mitochondria, large multi-vesicular bodies, and other types of intracellular organelles, eventually leading to neuron failure and death. The purpose of this paper is to develop a minimal model for a traffic jam in an axon based on a macroscopic (hydrodynamic) approach to modeling of highway traffic and on a macroscopic model of molecular-motor-assisted transport of intracellular organelles on microtubules.}, number={1}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Kuznetsov, A. V. and Avramenko, A. A.}, year={2009}, month={Jan}, pages={1–5} }
@article{xiang_kuznetsov_seyam_2009, title={Combined numerical and experimental investigation on the effect of jet pressure and forming belt geometry on the hydroentanglement process}, volume={100}, ISSN={["1754-2340"]}, DOI={10.1080/00405000701770563}, abstractNote={Hydroentanglement is a mechanical bonding process utilised to produce nonwoven fabrics. A web of loose fibres is put on a forming belt or perforated screen to form an integrated fabric with desired aesthetics by subjecting the web to multiple rows of fine high-pressure water jets. Mechanical performance of hydroentangled nonwovens is determined by the degree of the fibre entanglement, which depends on process parameters. This study presents the results of combined experimental and numerical investigation on the effects of the jet pressure and forming belt geometry on fibre entanglement. Extensive comparisons of simulations with experimental data are reported and analysed to give a clear understanding of the effect of fibreweb and forming belt properties on the critical jet pressure. The modelling results are in good correlation with experimental data for a wide range of jet pressures. The effect of the jet count per unit length on the degree of fibre entanglement is also investigated.}, number={4}, journal={JOURNAL OF THE TEXTILE INSTITUTE}, author={Xiang, P. and Kuznetsov, A. V. and Seyam, A. M.}, year={2009}, month={May}, pages={293–304} }
@article{kuznetsov_avramenko_blinov_2009, title={Effect of protein degradation in the axon on the speed of the bell-shaped concentration wave in slow axonal transport}, volume={36}, ISSN={["1879-0178"]}, DOI={10.1016/j.icheatmasstransfer.2009.04.002}, abstractNote={This paper investigates the effect of degradation of proteins transported by means of slow axonal transport (due to enzyme-mediated breakdown of proteins) on the speed of the bell-shaped wave of protein concentration propagating toward the synapse of the axon. Another issue investigated in this paper is the effect of protein degradation on the traffic jam caused by a decay of microtubule tracks at a certain location in the axon. The decay of microtubule tracks may be caused by misregulation of microtubule-associated proteins resulting from an imbalance in intracellular signaling or by mutations of these proteins. Axonal swellings caused by such traffic jams hinder axonal transport; they are a likely cause of various neurodegenerative diseases, including Alzheimer's and Parkinson's diseases and the Down syndrome.}, number={7}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Kuznetsov, A. V. and Avramenko, A. A. and Blinov, D. G.}, year={2009}, month={Aug}, pages={641–645} }
@article{xiang_kuznetsov_seyam_2009, title={Experimental and numerical investigation of the peeling force required for the detachment of fabric from the forming belt in the hydroentanglement process}, volume={100}, ISSN={["1754-2340"]}, DOI={10.1080/00405000701679723}, abstractNote={Hydroentanglement is a fast-growing process for manufacturing non-woven fabrics. In this process, multiple fine jets of highly pressurised water are directed towards a fibreweb composed initially of loose fibres, supported by the forming belt. The impact of the jets causes fibre entanglement in the fibreweb and produces an integrated fabric with desired aesthetics. It is important that, at the end of the process, the fibreweb could be easily separated from the forming wires. In this paper, the peeling force required for the separation of the hydroentangled fabric from the forming wires is measured experimentally. Numerical simulations of the hydroentanglement process are also carried out to predict the probability of fibres to be pushed in the knuckles of the forming wires. The fibres that get caught in the knuckles are mainly responsible for the peeling force of the fabric from the forming wires. The fibreweb is modelled as a porous layer, which is supported by forming wires. By correlating experimental results with simulations, a mathematical model, which is based on simulating average vorticity around the forming wires, is developed to predict the peeling force. The effect of the thickness of the fibreweb layer on the peeling force is investigated.}, number={2}, journal={JOURNAL OF THE TEXTILE INSTITUTE}, author={Xiang, P. and Kuznetsov, A. V. and Seyam, A. M.}, year={2009}, pages={99–110} }
@article{nield_kuznetsov_2009, title={Forced Convection With Laminar Pulsating Counterflow in a Saturated Porous Channel}, volume={131}, ISSN={["1528-8943"]}, DOI={10.1115/1.3180810}, abstractNote={An analytical solution is obtained for forced convection in a parallel-plate channel occupied by a layered saturated porous medium with counterflow produced by pulsating pressure gradients. The case of asymmetrical constant heat-flux boundary conditions is considered, and the Brinkman model is employed for the porous medium. A perturbation approach is used to obtain analytical expressions for the velocity, temperature distribution, and transient Nusselt number for convection produced by an applied pressure gradient that fluctuates with small amplitude harmonically in time about a nonzero mean. It is shown that the fluctuating part of the Nusselt number alters in magnitude and phase as the dimensionless frequency increases. The magnitude increases from zero, goes through a peak, and then decreases to zero. The height of the peak depends on the values of various parameters. The phase (relative to that of the steady component) decreases as the frequency increases. The phase angle at very low frequency can be π/2 or −π/2 depending on the degree of asymmetry of the heating and the values of other parameters.}, number={10}, journal={JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2009}, month={Oct} }
@article{kuznetsov_nield_2009, title={Forced Convection with Laminar Pulsating Counterflow in a Saturated Porous Circular Tube}, volume={77}, ISSN={["1573-1634"]}, DOI={10.1007/s11242-008-9271-3}, number={3}, journal={TRANSPORT IN POROUS MEDIA}, author={Kuznetsov, A. V. and Nield, D. A.}, year={2009}, month={Apr}, pages={447–462} }
@article{kuznetsov_nield_2009, title={Forced convection with counterflow in a circular tube occupied by a porous medium}, volume={12}, DOI={10.1615/JPorMedia.v12.i7.40}, abstractNote={An analytical solution is obtained for forced convection with counterflow in the core and sheath of a circular tube occupied by a saturated porous medium. The Brinkman model is employed for the porous medium. It is found that the effect of counterflow (in contrast to flow in one direction) is to reduce the value of the Nusselt number for large values of the core-sheath coordinate ξ, but to increase it for small values of ξ. In particular, Nu takes a zero minimum value when the mean velocity is zero.}, number={7}, journal={Journal of Porous Media}, author={Kuznetsov, A. V. and Nield, D. A.}, year={2009}, pages={657–666} }
@article{avramenko_kuznetsov_2009, title={Instability of a slip flow in a curved channel formed by two concentric cylindrical surfaces}, volume={28}, ISSN={["1873-7390"]}, DOI={10.1016/j.euromechflu.2009.06.003}, abstractNote={Instability of a slip flow in a curved channel formed by two concentric cylindrical surfaces is investigated. Two cases are considered. In the first (Taylor–Couette flow) case the flow is driven by the rotation of the inner cylindrical surface; no azimuthal pressure gradient is applied. In the second case (Dean flow) both cylindrical surfaces are motionless, and the flow is driven by a constant azimuthal pressure gradient. The collocation method is used to find numerically the critical values of the Taylor and Dean numbers, which establish the instability criteria for these two cases. The dependencies of critical values of these numbers on the ratio between the radii of concave and convex walls and on the velocity slip coefficient are investigated.}, number={6}, journal={EUROPEAN JOURNAL OF MECHANICS B-FLUIDS}, author={Avramenko, A. A. and Kuznetsov, A. V.}, year={2009}, pages={722–727} }
@article{kuznetsov_avramenko_blinov_2009, title={Macroscopic modeling of slow axonal transport of rapidly diffusible soluble proteins}, volume={36}, ISSN={["1879-0178"]}, DOI={10.1016/j.icheatmasstransfer.2009.01.005}, abstractNote={The purpose of this paper is to develop a macroscopic model of slow axonal transport of soluble proteins which may be transported in axons by both diffusion and active molecular-motor-assisted transport mechanisms. The model relies on the "stop-and-go" hypothesis put forward by Brown et al. [A. Brown, L. Wang, P. Jung, Stochastic simulation of neurofilament transport in axons: the "stop-and-go" hypothesis, Molecular Biology of the Cell 16 (2005) 4243–4255.] according to which the motion of neurofilaments in slow axonal transport does not occur at a constant velocity; instead, neurofilaments move along microtubules alternating between short periods of rapid movement, short on-track pauses, and prolonged off-track pauses, when they temporarily disengage from microtubules. For soluble proteins, diffusion may also play an important role in overall slow axonal transport; to account for this effect governing equations of the dynamic system model developed in Craciun et al. [G. Craciun, A. Brown, A. Friedman, A dynamical system model of neurofilament in axons, Journal of Theoretical Biology 237 (2005) 316–322.] are extended to incorporate diffusivity of off track proteins (proteins unbound to a stationary matrix). The model correctly predicts that the total concentration of organelles forms the bell-shaped wave that spreads out as it propagates toward the axon tip.}, number={4}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Kuznetsov, A. V. and Avramenko, A. A. and Blinov, D. G.}, year={2009}, month={Apr}, pages={293–296} }
@article{avramenko_kuznetsov_2009, title={Start-up flow in a channel or pipe occupied by a fluid-saturated porous mediaum}, volume={12}, DOI={10.1615/jpormedia.v12.i4.60}, abstractNote={The response of incompressible fluid in a parallel-plate channel or circular pipe, occupied by a fluid-saturated porous medium, to a suddenly imposed time-independent pressure drop is investigated. The Brinkman-expended Darcy equation is used to model momentum transport in the fluid. The problem is solved analytically using the Laplace transformation. The unsteady velocity profiles in a channel or pipe are presented through infinite series solutions. As expected, the flow asymptotically attains the fully developed velocity distribution, which is attained faster for the medium of smaller permeability.}, number={4}, journal={Journal of Porous Media}, author={Avramenko, A. A. and Kuznetsov, A. V.}, year={2009}, pages={361–367} }
@article{nield_kuznetsov_2009, title={The Cheng-Minkowycz problem for natural convective boundary-layer flow in a porous medium saturated by a nanofluid}, volume={52}, ISSN={["1879-2189"]}, DOI={10.1016/j.ijheatmasstransfer.2009.07.024}, abstractNote={The Cheng–Minkowycz problem of natural convection past a vertical plate, in a porous medium saturated by a nanofluid, is studied analytically. The model used for the nanofluid incorporates the effects of Brownian motion and thermophoresis. For the porous medium the Darcy model is employed. A similarity solution is presented. This solution depends on a Lewis number Le, a buoyancy-ratio number Nr, a Brownian motion number Nb, and a thermophoresis number Nt. The dependency of the Nusslelt number on these four parameters is investigated.}, number={25-26}, journal={INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2009}, month={Dec}, pages={5792–5795} }
@article{nield_kuznetsov_simmons_2009, title={The Effect of Strong Heterogeneity on the Onset of Convection in a Porous Medium}, volume={77}, ISSN={["1573-1634"]}, DOI={10.1007/s11242-008-9297-6}, number={2}, journal={TRANSPORT IN POROUS MEDIA}, author={Nield, D. A. and Kuznetsov, A. V. and Simmons, Craig T.}, year={2009}, month={Mar}, pages={169–186} }
@article{nield_kuznetsov_2009, title={The effect of a transition layer between a fluid and a porous medium: shear flow in a channel}, volume={78}, ISSN={["1573-1634"]}, DOI={10.1007/s11242-009-9342-0}, number={3}, journal={TRANSPORT IN POROUS MEDIA}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2009}, month={Jul}, pages={477–487} }
@article{nield_kuznetsov_2009, title={Thermal instability in a porous medium layer saturated by a nanofluid}, volume={52}, ISSN={["1879-2189"]}, DOI={10.1016/j.ijheatmasstransfer.2009.07.023}, abstractNote={The onset of convection in a horizontal layer of a porous medium saturated by a nanofluid is studied analytically. The model used for the nanofluid incorporates the effects of Brownian motion and thermophoresis. The analysis reveals that for a typical nanofluid (with large Lewis number) the prime effect of the nanofluids is via a buoyancy effect coupled with the conservation of nanoparticles, the contribution of nanoparticles to the thermal energy equation being a second-order effect. It is found that the critical thermal Rayleigh number can be reduced or increased by a substantial amount, depending on whether the basic nanoparticle distribution is top-heavy or bottom-heavy, by the presence of the nanoparticles. Oscillatory instability is possible in the case of a bottom-heavy nanoparticle distribution.}, number={25-26}, journal={INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2009}, month={Dec}, pages={5796–5801} }
@article{kuznetsov_nield_2009, title={Thermally Developing Forced Convection in a Porous Medium Occupied by a Rarefied Gas: Parallel Plate Channel or Circular Tube with Walls at Constant Heat Flux}, volume={76}, ISSN={["1573-1634"]}, DOI={10.1007/s11242-008-9250-8}, number={3}, journal={TRANSPORT IN POROUS MEDIA}, author={Kuznetsov, A. V. and Nield, D. A.}, year={2009}, month={Feb}, pages={345–362} }
@article{nield_kuznetsov_2008, title={A bioheat transfer model: Forced convection in a channel occupied by a porous medium with counterflow}, volume={51}, ISSN={["1879-2189"]}, DOI={10.1016/j.ijheatmasstransfer.2008.04.015}, abstractNote={An illustrative model for bioheat transfer is developed. An analytical solution is obtained for forced convection in a parallel plate channel occupied by a layered saturated porous medium with counterflow, the dominant feature that distinguishes bioheat transfer from other forms of heat transfer. The case of asymmetrical constant heat-flux boundary conditions is considered and the Brinkman model is employed for the porous medium. It is found that the Nusselt number Nu is zero when the mean velocity is zero, and negative values can be attained.}, number={23-24}, journal={INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2008}, month={Nov}, pages={5534–5541} }
@article{zheng_ordon_scharton_kuznetsov_roberts_2008, title={A new acoustic model for valveless pulsejets and its application to optimization thrust}, volume={130}, ISSN={["0742-4795"]}, DOI={10.1115/1.2900730}, abstractNote={Due to its simplicity, the valveless pulsejet may be an ideal low cost propulsion system. In this paper, a new acoustic model is described, which can accurately predict the operating frequency of a valveless pulsejet. Experimental and computational methods were used to investigate how the inlet and exhaust area and the freestream velocity affect the overall performance of a 50cm pulsejet. Pressure and temperature were measured at several axial locations for different fuel flow rates and different geometries. Computer simulations were performed for exactly the same geometries and fuel flow rates using a commercial CFD package (CFX) to develop further understanding of the factors that affect the performance of a valveless pulsejet. An acoustic model was developed to predict the frequency of these valveless pulsejets. The new model treats the valveless pulsejet engine as a combination of a Helmholtz resonator and a wave tube. This new model was shown to accurately predict geometries for maximum thrust. The model was further extended to account for the effect of freestream velocity. Evidence is provided that valveless pulsejet generates the highest thrust when the inherent inlet frequency matches the inherent exhaust frequency.}, number={4}, journal={JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER-TRANSACTIONS OF THE ASME}, author={Zheng, F. and Ordon, R. L. and Scharton, T. D. and Kuznetsov, A. V. and Roberts, W. L.}, year={2008}, month={Jul} }
@article{xiang_kuznetsov_seyam_2008, title={A porous medium model of the hydroentanglement process}, volume={11}, ISSN={["1934-0508"]}, DOI={10.1615/JPorMedia.v11.i1.30}, abstractNote={In the hydroentanglement process, a fiberweb composed of initially loose fibers, which is supported by forming wires, continuously passes under several manifolds of multiple fine jets of highly pressurized water. The impact of the jets causes fiber entanglement in the fiberweb and produces a high-quality fabric. In this article, a theoretical model of the hydroentanglement process is developed. The fiberweb is modeled as a porous layer, which is supported by a periodic net of forming wires. The model is based on the assumption that the degree of fiber entanglement and, consequently, the strength of the fabric are proportional to the average water vorticity in the fiberweb. Numerical simulations are performed to study the water flow field and the vorticity in the fiberweb. The effects of the thickness of the porous fiberweb layer, its permeability, and the inlet water jet velocity on the degree of fiber entanglement are investigated. Simulations show that most of the fibers are entangled in the MD-CD plane. There is a critical fiberweb thickness for a given jet pressure, and a critical jet velocity for a given fiberweb thickness. If the fiberweb thickness or jet velocity is larger than critical, the process is not efficient.}, number={1}, journal={JOURNAL OF POROUS MEDIA}, author={Xiang, P. and Kuznetsov, A. V. and Seyam, A. M.}, year={2008}, pages={35–49} }
@article{kuznetsov_avramenko_2008, title={Analytical investigation of transient molecular-motor-assisted transport in elongated cells}, volume={6}, ISSN={["1644-3608"]}, DOI={10.2478/s11534-008-0009-1}, abstractNote={Abstract}, number={1}, journal={CENTRAL EUROPEAN JOURNAL OF PHYSICS}, author={Kuznetsov, Andrey V. and Avramenko, Andriy A.}, year={2008}, month={Mar}, pages={45–51} }
@article{kuznetsov_2008, title={Analytical solution of the steady-state molecular-motor-assisted transport equations governing distribution of intracellular particles within a cell dendrite}, volume={35}, ISSN={["1879-0178"]}, DOI={10.1016/j.icheatmasstransfer.2008.04.013}, abstractNote={A steady-state analytical solution is obtained for a one-dimensional problem describing transport of intracellular organelles in a cell arm (a dendrite or axon). The model of intracellular trafficking of organelles (intracellular particles) is based on molecular-motor-assisted transport equations suggested by Smith and Simmons [D.A. Smith, R.M. Simmons, Models of motor-assisted transport of intracellular particles, Biophysical Journal 80 (2001) 45–68.]. According to this model, a fraction of intracellular space is occupied by filaments (microtubules); the remaining space allows for diffusion of unbound particles. Depending on the direction of particle transport provided by molecular motors running along these microtubules, the microtubules are divided into inward and outward microtubules. Unbound (free) organelles may bind to microtubules; organelles attached to microtubules may detach from them; the binding/detachment kinetic processes are specified by the first rate constants.}, number={8}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Kuznetsov, A. V.}, year={2008}, month={Oct}, pages={881–884} }
@article{nield_kuznetsov_2008, title={Effects of combined horizontal and vertical heterogeneity on the onset of transient convection in a porous medium}, volume={11}, DOI={10.1615/jpormedia.v11.i4.40}, abstractNote={The effects of both horizontal and vertical hydrodynamic and thermal heterogeneity on the onset of convection in a horizontal layer of a saturated porous medium, uniformly heated from below but with a nonuniform basic temperature gradient resulting from transient heating or otherwise, are studied analytically using linear stability theory for the case of weak heterogeneity. It is found that the effect of such heterogeneity on the critical value of the Rayleigh number Ra based on mean properties is of second order if the properties vary in a piecewise constant or linear fashion. The effects of horizontal heterogeneity and vertical heterogeneity are then comparable once the aspect ratio is taken into account and, to a first approximation, are independent.}, number={4}, journal={Journal of Porous Media}, author={Nield, A. A. and Kuznetsov, A. V.}, year={2008}, pages={377–387} }
@article{avramenko_kuznetsov_2008, title={Flow in a curved porous channel with a rectangular cross section}, volume={11}, DOI={10.1615/jpormedia.v11.i3.20}, abstractNote={Laminar flow in a curved channel with a rectangular cross section is investigated. The channel is occupied by a fluid-saturated porous medium. The flow is driven by a constant azimuthal pressure gradient. The Brinkman extension of the Darcy law is utilized; the momentum equation takes into account the Darcy and Brinkman drag terms. An analytical solution for the velocity field is obtained using a generalized Fourier series. The velocity profile depends on the geometry of the channel (the inner and outer radii of the channel walls and the aspect ratio of the cross section) and the Darcy number.}, number={3}, journal={Journal of Porous Media}, author={Avramenko, A. A. and Kuznetsov, A. V.}, year={2008}, pages={241–246} }
@article{kuznetsov_avramenko_2008, title={Generalized Fourier series solution of equations governing molecular-motor-assisted transport of adenoviral vectors in a spherical cell}, volume={35}, ISSN={["1879-0178"]}, DOI={10.1016/j.icheatmasstransfer.2007.08.003}, abstractNote={This paper presents an analytical solution of one-dimensional transient molecular-motor-assisted transport equations that describe transport of adenoviruses in a spherical cell. The model of intracellular trafficking of adenoviruses is based on molecular-motor-assisted transport equations suggested by Smith and Simmons [D.A. Smith, R.M. Simmons, Models of motor-assisted transport of intracellular particles, Biophysical Journal 80 (2001) 45–68.]. These equations are presented in spherical coordinates and extended by accounting for the random component of motion of viral particles bound to filaments. This random component is associated with the stochastic nature of molecular motors responsible for the locomotion of viral particles bound to filaments. Utilizing the method of separation of variables, a generalized Fourier series solution for this problem is obtained. The solution uses two different orthogonal sets of eigenfunctions to represent the concentration of free viral particles transported by diffusion and the concentration of microtubule-bound viral particles transported by kinesin-family molecular motors away from the cell nucleus. Binding/detachment kinetic processes between the viral particles and microtubules are specified by first rate reaction constants; these lead to coupling between the two viral concentrations. The obtained solution simulates viral transport between the cell membrane and cell nucleus during initial stages of viral infection.}, number={4}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Kuznetsov, A. V. and Avramenko, A. A.}, year={2008}, month={Apr}, pages={395–403} }
@article{zhu_kuznetsov_sandeep_2008, title={Investigation of a particulate flow containing spherical particles subjected to microwave heating}, volume={44}, ISSN={["1432-1181"]}, DOI={10.1007/s00231-007-0264-5}, number={4}, journal={HEAT AND MASS TRANSFER}, author={Zhu, J. and Kuznetsov, A. V. and Sandeep, K. P.}, year={2008}, month={Feb}, pages={481–493} }
@article{kuznetsov_hooman_2008, title={Modeling traffic jams in intracellular transport in axons}, volume={51}, ISSN={["1879-2189"]}, DOI={10.1016/j.ijheatmasstransfer.2008.04.022}, abstractNote={Irregularities in intracellular traffic in axons caused by mutations of molecular motors may lead to "traffic jams", which often result in swelling of axons causing various neurodegenerative diseases. The purpose of this paper is to suggest a model of the formation of traffic jams in axons during molecular-motor-assisted transport of intracellular organelles utilizing transport equations developed in Smith and Simmons [D.A. Smith, R.M. Simmons, Models of motor-assisted transport of intracellular particles, Biophys. J. 80 (2001) 45–68], which describe the motion of intracellular particles under the combined action of diffusion and motor-driven transport. According to this model, large intracellular organelles are transported in the cytoplasm by a combined action of diffusion and motor-driven transport. In an axon, organelles are transported away from the neuron's body toward the axon's terminal by kinesin-family molecular motors running on tracks composed by microtubules; old and used components are carried back toward neuron's body by dynein-family molecular motors. Binding/detachment kinetic processes between the organelles and microtubules are specified by first rate reaction constants; these lead to coupling between the three organelle concentrations.}, number={23-24}, journal={INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER}, author={Kuznetsov, A. V. and Hooman, K.}, year={2008}, month={Nov}, pages={5695–5699} }
@article{nield_kuznetsov_2008, title={Natural convection about a vertical plate embedded in a bidisperse porous medium}, volume={51}, ISSN={["1879-2189"]}, DOI={10.1016/j.ijheatmasstransfer.2007.07.011}, abstractNote={The classical Cheng–Minkowycz study of convection past a vertical plate embedded in a porous medium has been extended to the case of a bidisperse porous medium (BDPM). The boundary layer analysis leads to expressions for the velocity and temperature fields in terms of a geometrical parameter, an inter-phase momentum transfer parameter, a thermal diffusivity ratio, a permeability ratio, a thermal conductivity ratio, and an inter-phase heat transfer parameter. For the leading edge region, and for an inner layer, a similarity solution is obtained numerically. This involves the first four parameters, each of which is a characteristic of the BDPM.}, number={7-8}, journal={INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2008}, month={Apr}, pages={1658–1664} }
@article{kuznetsov_avramenko_blinov_2008, title={Numerical modeling of molecular-motor-assisted transport of adenoviral vectors in a spherical cell}, volume={11}, ISSN={["1476-8259"]}, DOI={10.1080/10255840701700957}, abstractNote={Viral gene delivery in a spherical cell is investigated numerically. The model of intracellular trafficking of adenoviruses is based on molecular-motor-assisted transport equations suggested by Smith and Simmons. These equations are presented in spherical coordinates and extended by accounting for the random component of motion of viral particles bound to filaments. This random component is associated with the stochastic nature of molecular motors responsible for locomotion of viral particles bound to filaments. The equations are solved numerically to simulate viral transport between the cell membrane and cell nucleus during initial stages of viral infection.}, number={3}, journal={COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING}, author={Kuznetsov, A. V. and Avramenko, A. A. and Blinov, D. G.}, year={2008}, month={Jun}, pages={215–222} }
@article{nield_simmons_kuznetsov_ward_2008, title={On the evolution of salt lakes: Episodic convection beneath an evaporating salt lake}, volume={44}, ISSN={["1944-7973"]}, DOI={10.1029/2007wr006161}, abstractNote={The transient evolution of salt lake brines and the accompanying underlying groundwater salinity distribution with depth is discussed. A convective‐diffusive equation with a novel surface source term modeling the evaporative process is introduced, and an approximate analytical solution of this equation is obtained using a perturbation approach. A linear stability analysis of the resulting solution is carried out. For typical field‐scale parameters, the model predicts that instability may initially occur within timescales on the order of weeks or decades and that a near‐surface layer of salty fluid whose thickness is on the order of decimeters is responsible for the initial onset of convection. Furthermore, the analysis indicates that when convection starts, the decimeter layer mixes, and this results in the loss of the destabilizing force. In this period, the salty fluid diffuses downward. This results in a return to a hydrologic system, where the salt profile is then well mixed throughout, but now with a background concentration with a higher average salinity. The process can then repeat for an extensive but finite period as the surface layer and subsurface groundwater concentration eventually become hypersaline and where salt precipitation occurs. We have called this phenomenon episodic convection. Variable‐density groundwater flow and solute transport modeling experiments of a field‐based salt lake system confirm the existence of episodic convection and semiquantitatively validate the findings of the analytical approach.}, number={2}, journal={WATER RESOURCES RESEARCH}, author={Nield, D. A. and Simmons, C. T. and Kuznetsov, A. V. and Ward, J. D.}, year={2008}, month={Feb} }
@article{xiang_kuznetsov_2008, title={Simulation of shape dynamics of along flexible fiber in a turbulent flow in the hydroentanglement process}, volume={35}, ISSN={["1879-0178"]}, DOI={10.1016/j.icheatmasstransfer.2008.01.006}, abstractNote={This paper presents the numerical investigation of dynamics of the shape of a long flexible fiber subjected to a turbulent flow field caused by impinging jets in the hydroentanglement process. The shape change of a long flexible fiber is simulated utilizing the rod–chain model following the method developed in Wang et al. [G. Wang, W. Yu, C. Zhou, Optimization of the rod chain model to simulate the motion of a long flexible fiber in simple shear flows, European Journal of Mechanics B/Fluids 25 (2006) 337–347.]. The method is extended to simulate the fiber movement in a turbulent flow field; two-dimensional simulations are performed. The shape of the fiber is determined by forces and torques exerted on it by the surrounding fluid as well as by the neighboring fibers. Numerical results are obtained for two model representations of the same fiber which differ by the number of rods used to represent the fiber.}, number={5}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Xiang, P. and Kuznetsov, A. V.}, year={2008}, month={May}, pages={529–534} }
@article{kuznetsov_nield_2008, title={The effect of a transition layer between a fluid and a porous medium: Forced convection in a channel}, volume={130}, ISSN={["1528-8943"]}, DOI={10.1115/1.2945905}, abstractNote={Flow in a three-layer channel is modeled analytically. The channel consists of a transition layer sandwiched between a porous medium and a fluid clear of solid material. Within the transition layer, the reciprocal of the permeability varies linearly across the channel. The Brinkman model is used for the momentum equations for the porous medium layer and the transition layer. The velocity profile is obtained in closed form in terms of Airy, exponential, and polynomial functions and this is employed to find analytically the Nusselt number for fully developed forced convection with boundaries subject to uniform and constant heat flux.}, number={9}, journal={JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME}, author={Kuznetsov, A. V. and Nield, D. A.}, year={2008}, month={Sep} }
@article{nield_kuznetsov_2008, title={The effects of combined horizontal and vertical heterogeneity on the onset of convection in a porous medium: Moderate heterogeneity}, volume={51}, ISSN={["1879-2189"]}, DOI={10.1016/j.ijheatmasstransfer.2007.08.011}, abstractNote={The effects of hydrodynamic and thermal heterogeneity, for the case of variation in both the horizontal and vertical directions, on the onset of convection in a horizontal layer of a saturated porous medium uniformly heated from below, are now studied analytically for the case of moderate heterogeneity (rather than the weak heterogeneity previously studied), for the case of a square box where the properties vary in a piecewise constant or linear fashion, with conducting impermeable top and bottom boundaries and insulating impermeable sidewalls. In order to allow for the moderate heterogeneity the order of the Galerkin expansion employed has been increased, and the expansion of a determinant of high order has been avoided by the use of a least squares methodology to find the critical value of the Rayleigh number Ra. It is found that the effects of permeability heterogeneity and conductivity heterogeneity each cause a reduction in the critical value of Ra in all cases, and the effects of horizontal and vertical heterogeneity are still approximately additive.}, number={9-10}, journal={INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2008}, month={May}, pages={2361–2367} }
@article{kuznetsov_nield_2008, title={The effects of combined horizontal and vertical heterogeneity on the onset of convection in a porous medium: double diffusive case}, volume={72}, ISSN={["1573-1634"]}, DOI={10.1007/s11242-007-9141-4}, number={2}, journal={TRANSPORT IN POROUS MEDIA}, author={Kuznetsov, A. V. and Nield, D. A.}, year={2008}, month={Mar}, pages={157–170} }
@article{kuznetsov_avramenko_2008, title={The method of separation of variables for solving equations describing molecular-motor-assisted transport of intracellular particles in a dendrite or axon}, volume={464}, ISSN={["1471-2946"]}, DOI={10.1098/rspa.2008.0127}, abstractNote={This paper presents an analytical solution of one-dimensional transient molecular-motor-assisted transport equations that describe transport of different organelles (such as transport vesicles loaded with a cargo of specific proteins) in a neuron's axon or dendrite. Large intracellular organelles are transported in the cytoplasm by a combined action of diffusion and motor-driven transport. In an axon, organelles are transported away from the neuron's body towards the axon's terminal by kinesin-family molecular motors running on tracks composed of microtubules (MTs); old and used components are carried back towards the neuron's body by dynein-family molecular motors. Using the method of separation of variables, a generalized Fourier series solution for this problem is obtained. The solution uses three different orthogonal sets of eigenfunctions to represent the concentration of free organelles transported by diffusion, MT-bound organelles transported away from the neuron's body, and MT-bound organelles transported towards the neuron's body. Binding/detachment kinetic processes between the organelles and the MT are specified by first-order rate constants; these lead to coupling between the three organelle concentrations.}, number={2099}, journal={PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES}, author={Kuznetsov, A. V. and Avramenko, A. A.}, year={2008}, month={Nov}, pages={2867–2886} }
@article{becker_kuznetsov_2008, title={Thermal in vivo skin electroporation pore development and charged macromolecule transdermal delivery: A numerical study of the influence of chemically enhanced lower lipid phase transition temperatures}, volume={51}, ISSN={["1879-2189"]}, DOI={10.1016/j.ijheatmasstransfer.2007.06.010}, abstractNote={Electroporation is an approach used to enhance transdermal transport of large molecules in which the skin is exposed to a series of electric pulses. Electroporation temporarily destabilizes the structure of the outer skin layer, the stratum corneum, by creating microscopic pores through which agents, which ordinarily are unable to pass into the skin, are able to pass through this outer barrier. Long duration electroporation pulses can cause localized temperature rises which result in thermotropic phase transitions within the lipid bilayer matrix of the stratum corneum. Chemical agents applied to the skin can reduce the lipid phase transition temperatures. This paper studies the benefits of the combination of the chemical enhancer, terpene d-limonene with low voltage electroporation pulses in order to further aid in electroporation pore development resulting from fluidization of the lipid structures within the stratum corneum. A transient finite volume model is developed in which the thermal and electrical behavior associated with electroporation of in vivo human skin is analyzed and lipid phase transition is represented by a melting process. The Nernst–Planck model is used to represent the electrophoretic-assisted transport of large charged molecules through the skin. The results show that the lower lipid phase transition temperatures associated with the topical application of chemical enhancers to the skin allow for increased solute delivery and solute penetration of the skin reaching radial locations much further than in the untreated case. Solute transport solutions of both cases exhibit local accumulation of concentrations below the stratum corneum – epidermis interface which exceed concentration values initially contained within the applicator gel.}, number={7-8}, journal={INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER}, author={Becker, S. M. and Kuznetsov, A. V.}, year={2008}, month={Apr}, pages={2060–2074} }
@article{rees_nield_kuznetsov_2008, title={Vertical free convective boundary-layer flow in a bidisperse porous medium}, volume={130}, ISSN={["1528-8943"]}, DOI={10.1115/1.2943304}, abstractNote={In this article, we study the effect of adopting a two-temperature and two-velocity model, appropriate to a bidisperse porous medium (BDPM), on the classical Cheng–Minkowycz study of vertical free convection boundary-layer flow in a porous medium. It is shown that the boundary-layer equations can be expressed in terms of three parameters: a modified volume fraction, a modified thermal conductivity ratio, and a third parameter incorporating both thermal and BDPM properties. A numerical simulation of the developing boundary layer is guided by a near-leading-edge analysis and supplemented by a far-field analysis. The study is completed by a presentation of numerical simulations of the elliptic equations in order to determine how the adoption of the BDPM model affects the thermal fields in the close vicinity of the origin.}, number={9}, journal={JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME}, author={Rees, D. A. S. and Nield, D. A. and Kuznetsov, A. V.}, year={2008}, month={Sep} }
@article{kuznetsov_2007, title={Analytical solution of equations governing molecular-motor-assisted transport of intracellular particles}, volume={34}, ISSN={["1879-0178"]}, DOI={10.1016/j.icheatmasstransfer.2007.01.007}, abstractNote={Using the method of separation of variables, a generalized Fourier series solution is obtained for a one-dimensional transient problem describing the motor-assisted transport of intracellular organelles in a cell arm (a dendrite or axon), which is oriented in the x-direction. The one-dimensional transport of organelles occurs between two boundaries, the base of the dendrite and its tip. A fraction of space within the dendrite is occupied by filaments; the remaining space allows diffusion of unbound particles in the x-direction. The filaments are divided into outward filaments (molecular motors running along these filaments transport particles in the direction of increasing x) and inward filaments (molecular motors running along these filaments transport particles in the direction of decreasing x). Unbound (free) particles may bind to filaments; particles attached to filaments may detach from them; the binding/detachment kinetic processes are specified by the first rate constants.}, number={4}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Kuznetsov, A. V.}, year={2007}, month={Apr}, pages={391–398} }
@article{geng_schoen_kuznetsov_roberts_2007, title={Combined numerical and experimental investigation of a 15-cm valveless pulsejet}, volume={78}, ISSN={["1573-1987"]}, DOI={10.1007/s10494-006-9032-8}, number={1}, journal={FLOW TURBULENCE AND COMBUSTION}, author={Geng, T. and Schoen, M. A. and Kuznetsov, A. V. and Roberts, W. L.}, year={2007}, month={Jan}, pages={17–33} }
@article{geng_kiker_ordon_kuznetsov_zeng_roberts_2007, title={Combined numerical and experimental investigation of a hobby-scale pulsejet}, volume={23}, ISSN={["1533-3876"]}, DOI={10.2514/1.18593}, abstractNote={The pulsejet, due to its simplicity, may be an ideal micro propulsion system, but has received very little attention since the mid 1950’s. Here, modern computational and experimental tools are used to investigate the operation of a hobby scale (50 cm overall length) pulsejet. Gas dynamics, acoustics and chemical kinetics are all involved and are studied to gain an understanding of the various physical phenomena affecting pulsejet operation, scaleability and efficiency. A Bailey Machining Service (BMS) hobby pulsejet is instrumented to obtain pressure, temperature, thrust, and frequency. CH * chemiluminescence is utilized to determine combustion time and high speed imaging of the reed valve operation is undertaken to determine the valve duty cycle. Laser Doppler Velocimetry (LDV) has been used to measure the instantaneous exhaust velocity in these unsteady combustion devices. Numerical simulations are performed utilizing CFX to model the 3-D compressible vicious flow in the pulsejet using the integrated Westbrook-Dryer single step combustion model. The turbulent flow and reaction rate are modeled with the ke model and the Eddy Dissipation Model (EDM), respectively. Simulation results provide physical insight into the pulsejet cycle; comparisons with experimental data obtained in this research are carried out. The traditional view of a pulsejet as a 1/4 wave tube operating on the Humphrey cycle is modified with to account for valve operation and finite chemical kinetics.}, number={1}, journal={JOURNAL OF PROPULSION AND POWER}, author={Geng, T. and Kiker, A., Jr. and Ordon, R. and Kuznetsov, A. V. and Zeng, T. F. and Roberts, W. L.}, year={2007}, pages={186–193} }
@article{geng_kuznetsov_2007, title={Dynamics of large solid particles in bioconvective sedimentation}, volume={53}, ISSN={["1097-0363"]}, DOI={10.1002/fld.1301}, abstractNote={Abstract}, number={5}, journal={INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS}, author={Geng, P. and Kuznetsov, A. V.}, year={2007}, month={Feb}, pages={713–733} }
@article{geng_zheng_kiker_kuznetsov_roberts_2007, title={Experimental and numerical investigation of an 8-cm valveless pulsejet}, volume={31}, ISSN={["0894-1777"]}, DOI={10.1016/j.expthermflusci.2006.06.005}, abstractNote={This paper investigates the performance of a small scale pulsejet whose overall length is approximately 8 cm, the smallest pulsejet ever reported to the author's knowledge. Gas dynamics, acoustics and chemical kinetics were modeled to gain an understanding of various physical phenomena affecting pulsejet operation, scalability, and efficiency. Numerical simulations were performed utilizing CFX to model 3-D compressible vicious flow in the pulsejet using the integrated Westbrook–Dryer single step combustion model. The simulation results were validated with experimental data and provide physical insight into the pulsejet operation. The pulsejet was run in valveless mode on hydrogen fuel with either a forward-facing inlet or a pair of rearward-facing inlets. Pressure, temperature, thrust, and frequency were measured as a function of valveless inlet and exit lengths and different geometries. As expected, the rearward-facing inlet produced considerably more net thrust, although still not very efficient, with a TSFC of 0.02 kg/N-h. The operating frequency was found to scale with inlet length to the negative 0.22 power, in addition to the inverse of the overall length for valved pulsejet.}, number={7}, journal={EXPERIMENTAL THERMAL AND FLUID SCIENCE}, author={Geng, T. and Zheng, F. and Kiker, A. P. and Kuznetsov, An. and Roberts, W. L.}, year={2007}, month={Jul}, pages={641–647} }
@article{xiang_kuznetsov_seyam_2007, title={Fibers caught in the knuckles of the forming wires: Experimental measurements and physical origins of the force of peeling in the hydroentanglement process}, volume={2}, number={3}, journal={Journal of Engineered Fibers and Fabrics}, author={Xiang, P. and Kuznetsov, A. V. and Seyam, A. M.}, year={2007}, pages={1–9} }
@article{avramenko_kuznetsov_2007, title={Flow instability in a curved porous channel formed by two concentric cylindrical surfaces}, volume={69}, ISSN={["1573-1634"]}, DOI={10.1007/s11242-006-9078-z}, number={3}, journal={TRANSPORT IN POROUS MEDIA}, author={Avramenko, A. A. and Kuznetsov, A. V.}, year={2007}, month={Sep}, pages={373–381} }
@article{zheng_basciano_li_kuznetsov_2007, title={Fluid dynamics of cell cytokinesis - Numerical analysis of intracellular flow during cell division}, volume={34}, ISSN={["1879-0178"]}, DOI={10.1016/j.icheatmasstransfer.2006.09.005}, abstractNote={Intracellular flow of cytoplasmic fluid during cell cytokinesis is investigated. The intercellular bridge connecting two daughter cells is modeled as a cylindrical microchannel whose squeezing causes cytoplasmic flow inside the bridge itself and into the daughter cells. An equation from recent experimental measurements by Zhang and Robinson [W. Zhang, D.N. Robinson, Balance of actively generated contractile and resistive forces controls cytokinesis dynamics, Proceedings of the National Academy of Sciences of the United States of America 102 (2005) 7186–7191.] that governs the dynamics of bridge thinning is implemented in this model. The purpose of this research is to compute intracellular flow induced by the bridge thinning process. Two different types of boundary conditions are compared at the membrane–cytoplasm interface; these are a no-slip condition and a no tangential stress condition. Pressure and flow velocity distributions in the daughter cells and the force exerted by this flow on the daughter cell nucleus are computed. It is established that the pressure difference between the daughter cell and the intercellular bridge increases as time progresses. It is also observed that a region of stagnation develops on the downstream side of the nucleus as the bridge thins.}, number={1}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Zheng, F. and Basciano, C. and Li, J. and Kuznetsov, A. V.}, year={2007}, month={Jan}, pages={1–7} }
@article{nield_kuznetsov_2007, title={Forced convection with laminar pulsating flow in a channel or tube}, volume={46}, ISSN={["1778-4166"]}, DOI={10.1016/j.ijthermalsci.2006.07.011}, abstractNote={A perturbation approach is used to obtain analytical expressions for the velocity, temperature distribution, and transient Nusselt number for the problem of forced convection, in a parallel-plates channel or a circular tube, produced by an applied pressure gradient that fluctuates with small amplitude harmonically in time about a non-zero mean. It is found that the fluctuating part of this Nusselt number alters in magnitude and phase as the dimensionless frequency increases. The magnitude increases from zero, goes through a peak, and then decreases to zero. The height of the peak decreases as the Prandtl number Pr increases. The phase (relative to that of the steady component) decreases from π/2 to −π/2. When Pr=1 there is a weak singularity in the form of the temperature distribution, but the Nusselt number is not significantly different from the case when Pr≠1.}, number={6}, journal={INTERNATIONAL JOURNAL OF THERMAL SCIENCES}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2007}, month={Jun}, pages={551–560} }
@article{avramenko_kuznetsov_nield_2007, title={Instability of slip flow in a channel occupied by a hyperporous medium}, volume={10}, DOI={10.1615/jpormedia.v10.i5.20}, abstractNote={Stability of a slip flow in a channel occupied by a hyperporous medium saturated by a rarefied gas is investigated. The evolution equation for analyzing the effect of three-dimensional disturbances on this flow is obtained. Numerical analyses for two-dimensional and three-dimensional disturbances are carried out using the collocation method. The dependence of the critical Reynolds number on porosity and parameter σ (dependent on the Knudsen number) is investigated. Squire's theorem for the case of two-dimensional shear flows in a Navier-Stokes fluid, which states that two-dimensional disturbances are more critical for instability than three-dimensional disturbances, is extended to the case of this flow.}, number={5}, journal={Journal of Porous Media}, author={Avramenko, A. A. and Kuznetsov, A. V. and Nield, D. A.}, year={2007}, pages={435–442} }
@article{becker_kunetsov_2007, title={Local temperature rises influence in vivo electroporation pore development: A numerical stratum corneum lipid phase transition model}, volume={129}, ISSN={["1528-8951"]}, DOI={10.1115/1.2768380}, abstractNote={Electroporation is an approach used to enhance transdermal transport of large molecules in which the skin is exposed to a series of electric pulses. Electroporation temporarily destabilizes the structure of the outer skin layer, the stratum corneum, by creating microscopic pores through which agents, ordinarily unable to pass into the skin, are able to pass through this outer barrier. Long duration electroporation pulses can cause localized temperature rises, which result in thermotropic phase transitions within the lipid bilayer matrix of the stratum corneum. This paper focuses on electroporation pore development resulting from localized Joule heating. This study presents a theoretical model of electroporation, which incorporates stratum corneum lipid melting with electrical and thermal energy equations. A transient finite volume model is developed representing electroporation of in vivo human skin, in which stratum corneum lipid phase transitions are modeled as a series of melting processes. The results confirm that applied voltage to the skin results in high current densities within the less resistive regions of the stratum corneum. The model captures highly localized Joule heating within the stratum corneum and subsequent temperature rises, which propagate radially outward. Electroporation pore development resulting from the decrease in resistance associated with lipid melting is captured by the lipid phase transition model. As the effective pore radius grows, current density and subsequent Joule heating values decrease.}, number={5}, journal={JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME}, author={Becker, S. M. and Kunetsov, A. V.}, year={2007}, month={Oct}, pages={712–721} }
@article{zhu_kuznetsov_sandeep_2007, title={Mathematical modeling of continuous flow microwave heating of liquids (effects of dielectric properties and design parameters)}, volume={46}, ISSN={["1778-4166"]}, DOI={10.1016/j.ijthermalsci.2006.06.005}, abstractNote={A detailed numerical model is presented to study heat transfer in liquids as they flow continuously in a circular duct that is subjected to microwave heating. Three types of food liquids are investigated: apple sauce, skim milk, and tomato sauce. The transient Maxwell's equations are solved by the finite difference time domain (FDTD) method to describe the electromagnetic field in the microwave cavity and the waveguide. The temperature field inside the applicator duct is determined by the solution of the momentum, energy, and Maxwell's equations. Simulations aid in understanding the effects of dielectric properties of the fluid, the applicator diameter and its location, as well as the geometry of the microwave cavity on the heating process. Numerical results show that the heating pattern strongly depends on the dielectric properties of the fluid in the duct and the geometry of the microwave heating system.}, number={4}, journal={INTERNATIONAL JOURNAL OF THERMAL SCIENCES}, author={Zhu, J. and Kuznetsov, A. V. and Sandeep, K. P.}, year={2007}, month={Apr}, pages={328–341} }
@article{becker_kuznetsov_2007, title={Numerical assessment of thermal response associated with in vivo skin electroporation: The importance of the composite skin model}, volume={129}, ISSN={["1528-8951"]}, DOI={10.1115/1.2720910}, abstractNote={Electroporation is an approach used to enhance transdermal transport of large molecules in which the skin is exposed to a series of electric pulses. The structure of the transport inhibiting outer layer, the stratum corneum, is temporarily destabilized due to the development of microscopic pores. Consequently agents that are ordinarily unable to pass into the skin are able to pass through this outer barrier. Of possible concern when exposing biological tissue to an electric field is thermal tissue damage associated with Joule heating. This paper shows the importance of using a composite model in calculating the electrical and thermal effects associated with skin electroporation. A three-dimensional transient finite-volume model of in vivo skin electroporation is developed to emphasize the importance of representing the skin’s composite layers and to illustrate the underlying relationships between the physical parameters of the composite makeup of the skin and resulting thermal damage potential.}, number={3}, journal={JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME}, author={Becker, S. M. and Kuznetsov, A. V.}, year={2007}, month={Jun}, pages={330–340} }
@article{zhu_kuznetsov_sandeep_2007, title={Numerical modeling of a moving particle in a continuous flow subjected to microwave heating}, volume={52}, ISSN={["1040-7782"]}, DOI={10.1080/00397910601150031}, abstractNote={Microwave heating of a food particle and carrier liquid as they flow continuously in a circular pipe is investigated numerically. The three-dimensional transient fluid flow as well as electromagnetic and temperature fields are described by a model that includes coupled Maxwell's, continuity, Navier-Stokes, and energy equations. The electromagnetic power and temperature distributions in both the liquid and the particle are taken into account. The hydrodynamic interaction between the solid particle and the carrier fluid is simulated by the force-coupling method (FCM). This article explores the effects of dielectric properties and the inlet position of the particle on microwave energy and temperature distributions inside the particle. The effect of the particle on power absorption in the carrier liquid is studied as well. The results show that electromagnetic power absorption by the particle is greatly influenced by the ratio of dielectric properties of the particle and the liquid as well as the distance between the particle and the location in the applicator where the electromagnetic power takes on its maximum value.}, number={5}, journal={NUMERICAL HEAT TRANSFER PART A-APPLICATIONS}, author={Zhu, J. and Kuznetsov, A. V. and Sandeep, K. P.}, year={2007}, pages={417–439} }
@article{zhu_kuznetsov_sandeep_2007, title={Numerical simulation of forced convection in a duct subjected to microwave heating}, volume={43}, ISSN={["1432-1181"]}, DOI={10.1007/s00231-006-0105-y}, number={3}, journal={HEAT AND MASS TRANSFER}, author={Zhu, J. and Kuznetsov, A. V. and Sandeep, K. P.}, year={2007}, month={Jan}, pages={255–264} }
@misc{nield_kuznetsov_2007, title={Reply to comments on 'Forced convection with slip-flow in a channel or duct occupied by a hyper-porous medium saturated by a rarefied gas'}, volume={67}, ISSN={["0169-3913"]}, DOI={10.1007/s11242-006-9070-7}, number={1}, journal={TRANSPORT IN POROUS MEDIA}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2007}, month={Mar}, pages={169–170} }
@article{xiang_kuznetsov_seyam_2007, title={Simulation of fiber entanglement by modeling vorticity in water flow field}, volume={77}, ISSN={["0040-5175"]}, DOI={10.1177/0040517506069158}, abstractNote={ This research developed a model of the hydroentanglement process, based on the first principles of fluid mechanics. This model proceeded from the assumption that fiber entanglement in the hydroentanglement process is proportional to the average vorticity in the fiberweb. Two-dimensional simulations of the water flow through the fiberweb and forming surfaces were performed in the plane perpendicular to the machine direction (MD). In these two-dimensional simulations the time-dependent development of the flow field was investigated, and it was found that the vortices induced by the water jets were influenced by the jet pressure and diameter. It was shown that the maximum average vorticity in the fiberweb occurred at a water jet diameter of 0.127 mm which explains why jets of such diameter are commonly used in industry. Three-dimensional simulations were also performed to account for the realistic geometry of the computational domain. The influence of the forming surface permeability was investigated and it was shown that the fiber entanglement increased as the open area of the forming surface decreased. }, number={5}, journal={TEXTILE RESEARCH JOURNAL}, author={Xiang, Ping and Kuznetsov, Andrey V. and Seyam, Abdel-Fattah M.}, year={2007}, month={Sep}, pages={312–329} }
@article{nield_kuznetsov_2007, title={The effect of combined vertical and horizontal heterogeneity on the onset of convection in a bidisperse porous medium}, volume={50}, ISSN={["1879-2189"]}, DOI={10.1016/j.ijheatmasstransfer.2007.01.027}, abstractNote={The effects of both horizontal and vertical hydrodynamic and thermal heterogeneity, on the onset of convection in a horizontal layer of a saturated bidisperse porous medium uniformly heated from below, are studied analytically using linear stability theory for the case of weak heterogeneity. It is found that the effect of such heterogeneity on the critical value of the Rayleigh number Ra based on mean properties is of second order if the properties vary in a piecewise constant or linear fashion. The effects of horizontal heterogeneity and vertical heterogeneity are then comparable once the aspect ratio is taken into account, and to a first approximation are independent. The thermal heterogeneity of the p-phase can be quite significant when the thermal diffusivity of that phase is large relative to that of the f-phase.}, number={17-18}, journal={INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2007}, month={Aug}, pages={3329–3339} }
@article{nield_kuznetsov_2007, title={The effects of combined horizontal and vertical heterogeneity and anisotropy on the onset of convection in a porous medium}, volume={46}, ISSN={["1778-4166"]}, DOI={10.1016/j.ijthermalsci.2007.01.005}, abstractNote={The effects of both horizontal and vertical hydrodynamic and thermal heterogeneity together with anisotropy of both permeability and thermal conductivity, on the onset of convection in a horizontal layer of a saturated porous medium, uniformly heated from below, are studied analytically using linear stability theory for the case of weak heterogeneity. It is found that the effect of such heterogeneity on the critical value of the Rayleigh number Ra based on mean properties is of second order if the properties vary in a piecewise constant or linear fashion. The effects of horizontal heterogeneity and vertical heterogeneity are then comparable once the aspect ratio is taken into account, and to a first approximation are independent. For a square enclosure, horizontal heterogeneity is invariably destabilizing, but vertical heterogeneity can be either stabilizing or destabilizing. For an enclosure whose aspect ratio is optimized to give the minimum value of the critical Rayleigh number, both horizontal and vertical heterogeneity are destabilizing, by an amount dependent on the ratio of the conductivity and permeability anisotropy measures.}, number={12}, journal={INTERNATIONAL JOURNAL OF THERMAL SCIENCES}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2007}, month={Dec}, pages={1211–1218} }
@article{nield_kuznetsov_2007, title={The effects of combined horizontal and vertical heterogeneity on the onset of convection in a porous medium}, volume={50}, ISSN={["1879-2189"]}, DOI={10.1016/j.ijheatmasstransfer.2006.09.023}, abstractNote={The effects of hydrodynamic and thermal heterogeneity, for the case of variation in both the horizontal and vertical directions, on the onset of convection in a horizontal layer of a saturated porous medium uniformly heated from below, are studied analytically for the case of weak heterogeneity. It is found that the effect of such heterogeneity on the critical value of the Rayleigh number Ra based on mean properties is of second order if the properties vary in a piecewise constant or linear fashion. The effects of horizontal heterogeneity and vertical heterogeneity are then comparable once the aspect ratio is taken into account, and to a first approximation are independent. For the case of conducting impermeable top and bottom boundaries and a square box, the effects of permeability heterogeneity and conductivity heterogeneity each cause a reduction in the critical value of Ra, while for the case of a tall box there can be either a reduction or an increase.}, number={9-10}, journal={INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2007}, month={May}, pages={1909–1915} }
@article{nield_kuznetsov_2007, title={The onset of convection in a porous medium occupying an enclosure of variable width or height}, volume={129}, ISSN={["0022-1481"]}, DOI={10.1115/1.2768097}, abstractNote={An analytical study is made of the onset of convection in a saturated porous medium occupying a two-dimensional enclosure of uniform height, but whose width is slowly varying in an arbitrary manner, or one of uniform width, but whose height is slowly varying in an arbitrary manner. It is found that the variation of width generally has a stabilizing effect, whereas variation of height generally has a destabilizing effect.}, number={12}, journal={JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2007}, month={Dec}, pages={1714–1718} }
@article{nield_kuznetsov_2007, title={The onset of convection in a shallow box occupied by a heterogeneous porous medium with constant flux boundaries}, volume={67}, ISSN={["1573-1634"]}, DOI={10.1007/s11242-006-9035-x}, number={3}, journal={TRANSPORT IN POROUS MEDIA}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2007}, month={Apr}, pages={441–451} }
@article{becker_kuznetsov_2007, title={Thermal damage reduction associated with in vivo skin electroporation: A numerical investigation justifying aggressive pre-cooling}, volume={50}, ISSN={["1879-2189"]}, DOI={10.1016/j.ijheatmasstransfer.2006.06.030}, abstractNote={Electroporation is an approach used to enhance transdermal transport of large molecules in which the skin is exposed to a series of electric pulses. Electroporation temporarily destabilizes the structure of the outer skin layer, the stratum corneum, by creating microscopic pores through which agents, which ordinarily are unable to pass into the skin, are able to pass through this outer barrier. Of possible concern when exposing biological tissue to an electric field is thermal tissue damage associated with Joule heating. In order to find the electrical and transient thermal solutions associated with this process, this study develops a three-dimensional transient finite-volume composite model of in vivo skin electroporation. The electroporation process modeled consists of five 150 ms long DC square wave pulses administered at 1-s intervals with an applied voltage of 400 V. This paper finds that minor thermal influence of the electrode plate and the of a small presence blood vessel have a large impact on thermal damage. An aggressive pre-cooling technique is presented which is shown to dramatically reduce the risk of thermal damage.}, number={1-2}, journal={INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER}, author={Becker, S. M. and Kuznetsov, A. V.}, year={2007}, month={Jan}, pages={105–116} }
@article{kuznetsov_nield_2006, title={Boundary layer treatment of forced convection over a wedge with an attached porous substrate}, volume={9}, DOI={10.1615/jpormedia.v9.i7.70}, number={7}, journal={Journal of Porous Media}, author={Kuznetsov, A. V. and Nield, D. A.}, year={2006}, pages={683–694} }
@article{geng_kuznetsov_2006, title={Direct numerical simulation of settling of a large solid particle during bioconvection}, volume={51}, ISSN={["1097-0363"]}, DOI={10.1002/fld.1125}, abstractNote={Abstract}, number={5}, journal={INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS}, author={Geng, P. and Kuznetsov, A. V.}, year={2006}, month={Jun}, pages={511–530} }
@article{kuznetsov_nield_2006, title={Forced convection with laminar pulsating flow in a saturated porous channel or tube}, volume={65}, ISSN={["1573-1634"]}, DOI={10.1007/s11242-006-6791-6}, number={3}, journal={TRANSPORT IN POROUS MEDIA}, author={Kuznetsov, A. V. and Nield, D. A.}, year={2006}, month={Dec}, pages={505–523} }
@article{nield_kuznetsov_2006, title={Forced convection with slip-flow in a channel or duct occupied by a hyper-porous medium saturated by a rarefied gas}, volume={64}, ISSN={["1573-1634"]}, DOI={10.1007/s11242-005-2341-x}, number={2}, journal={TRANSPORT IN POROUS MEDIA}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2006}, month={Aug}, pages={161–170} }
@article{chitrphiromsri_kuznetsov_song_barker_2006, title={Investigation of feasibility of developing intelligent firefighter-protective garments based on the utilization of a water-injection system}, volume={49}, ISSN={["1521-0634"]}, DOI={10.1080/10407780500359869}, abstractNote={ABSTRACT This research develops a new approach to designing and creating a prototype of an intelligent firefighter thermal-protective garment. During a flash fire exposure, this intelligent garment will absorb a significant amount of the incident heat flux due to evaporation of the injected water, thus limiting the temperature increase and the total heat flux to the firefighter's skin. A comprehensive mathematical model of heat and mass transport in the fabric layer during the flash fire exposure is suggested and numerically implemented using a finite-volume technique. A computational investigation is performed to optimize the performance of this novel garment system in terms of the activation temperature and the necessary amount of injected water.}, number={5}, journal={NUMERICAL HEAT TRANSFER PART A-APPLICATIONS}, author={Chitrphiromsri, P and Kuznetsov, AV and Song, G and Barker, RL}, year={2006}, month={Sep}, pages={427–450} }
@article{kuznetsov_2006, title={Investigation of the onset of bioconvection in a suspension of oxytactic microorganisms subjected to high-frequency vertical vibration}, volume={20}, ISSN={["1432-2250"]}, DOI={10.1007/s00162-006-0007-0}, number={2}, journal={THEORETICAL AND COMPUTATIONAL FLUID DYNAMICS}, author={Kuznetsov, AV}, year={2006}, month={Apr}, pages={73–87} }
@article{kuznetsov_2006, title={Linear stability analysis of the effect of vertical vibration on bioconvection in a horizontal porous layer of finite depth}, volume={9}, ISSN={["1934-0508"]}, DOI={10.1615/JPorMedia.v9.i6.80}, number={6}, journal={JOURNAL OF POROUS MEDIA}, author={Kuznetsov, A. V.}, year={2006}, pages={597–608} }
@article{kuznetsov_xiang_2006, title={Numerical investigation of thinning of the intercellular bridge during cell cytokinesis}, volume={33}, ISSN={["1879-0178"]}, DOI={10.1016/j.icheatmasstransfer.2006.05.005}, abstractNote={This paper develops a numerical model for intercellular bridge dynamics during the final stages of cell division known as cell cytokinesis. The aim of this research is to provide understanding as well as a quantitative description of transport processes during formation and thinning of the intercellular bridge. From a microfluidic standpoint, intercellular bridge is a squeezing microchannel or a squeezing pump. The rate of pumping based on squeezing increases with increased squeezing tension, which is determined by the number of myosin-II molecular motors recruited into the intercellular bridge region.}, number={9}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Kuznetsov, A. V. and Xiang, Ping}, year={2006}, month={Nov}, pages={1071–1078} }
@article{becker_kuznetsov_2006, title={Numerical modeling of in vivo plate electroporation thermal dose assessment}, volume={128}, ISSN={["1528-8951"]}, DOI={10.1115/1.2132375}, abstractNote={Electroporation is an approach used to enhance the transport of large molecules to the cell cytosol in which a targeted tissue region is exposed to a series of electric pulses. The cell membrane, which normally acts as a barrier to large molecule transport into the cell interior, is temporarily destabilized due to the development of pores in the cell membrane. Consequently, agents that are ordinarily unable enter the cell are able to pass through the cell membrane. Of possible concern when exposing biological tissue to an electric field is thermal tissue damage associated with joule heating. This paper explores the thermal effects of various geometric, biological, and electroporation pulse parameters including the blood vessel presence and size, plate electrode configuration, and pulse duration and frequency. A three-dimensional transient finite volume model of in vivo parallel plate electroporation of liver tissue is used to develop a better understanding of the underlying relationships between the physical parameters involved with tissue electroporation and resulting thermal damage potential.}, number={1}, journal={JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME}, author={Becker, SM and Kuznetsov, AV}, year={2006}, month={Feb}, pages={76–84} }
@article{kuznetsov_2006, title={Optimization problems for bioheat equation}, volume={33}, ISSN={["1879-0178"]}, DOI={10.1016/j.icheatmasstransfer.2006.01.012}, abstractNote={The minimum principal of Pontryagin is used solve an optimal control problem for heating a layer of tissue in order to destroy a cancerous tumor. Distributions of temperature and thermal dose in the tissue at different moments of time are computed numerically. The influence of the cool-off period on thermal dose accumulation is investigated.}, number={5}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Kuznetsov, A. V.}, year={2006}, month={May}, pages={537–543} }
@article{avramenko_kuznetsov_2006, title={Renormalization group model of large-scale turbulence in porous media}, volume={63}, ISSN={["1573-1634"]}, DOI={10.1007/s11242-005-4425-z}, number={1}, journal={TRANSPORT IN POROUS MEDIA}, author={Avramenko, AA and Kuznetsov, AV}, year={2006}, month={Apr}, pages={175–193} }
@article{nield_kuznetsov_2006, title={The onset of bio-thermal convection in a suspension of gyrotactic microorganisms in a fluid layer: Oscillatory convection}, volume={45}, ISSN={["1778-4166"]}, DOI={10.1016/j.ijthermalsci.2006.01.007}, abstractNote={A linear stability analysis is applied to investigate the onset of bioconvection in a horizontal layer of fluid containing a suspension of motile microorganisms with heating or cooling from below. With cooling from below the stabilizing effect of the thermal stratification is opposed to the destabilizing effect resulting from the congregation of the microorganisms, and oscillatory convection is possible in certain circumstances. The stability criterion is found in terms of a thermal Rayleigh number, a bioconvection Rayleigh number, a bioconvection Péclet number, a gyrotactic number, and a measure of the cell eccentricity, together with (in the case of oscillatory convection) a Prandtl number and a Lewis number.}, number={10}, journal={INTERNATIONAL JOURNAL OF THERMAL SCIENCES}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2006}, month={Oct}, pages={990–997} }
@article{nield_kuznetsov_2006, title={The onset of convection in a bidisperse porous medium}, volume={49}, ISSN={["1879-2189"]}, DOI={10.1016/j.ijheatmasstransfer.2006.02.008}, abstractNote={The classical Rayleigh–Bénard theory, for the onset of convection in a horizontal layer uniformly heated from below, has been applied to a bidisperse porous medium. The linear stability analysis leads to an expression for the critical Rayleigh number as a function of a Darcy number, two volume fractions, a permeability ratio, a thermal capacity ratio, a thermal conductivity ratio, an inter-phase heat transfer parameter and an inter-phase momentum transfer parameter.}, number={17-18}, journal={INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2006}, month={Aug}, pages={3068–3074} }
@article{avramenko_kuznetsov_2006, title={The onset of convection in a suspension of gyrotactic microorganisms in superimposed fluid and porous layers: Effect of vertical throughflow}, volume={65}, ISSN={["1573-1634"]}, DOI={10.1007/s11242-005-6086-3}, number={2}, journal={TRANSPORT IN POROUS MEDIA}, author={Avramenko, A. A. and Kuznetsov, A. V.}, year={2006}, month={Nov}, pages={159–176} }
@article{kuznetsov_2006, title={The onset of thermo-bioconvection in a shallow fluid saturated porous layer heated from below in a suspension of oxytactic microorganisms}, volume={25}, ISSN={["1873-7390"]}, DOI={10.1016/j.euromechflu.2005.06.003}, abstractNote={The aim of this paper is to present a continuum model for thermo-bioconvection of oxytactic bacteria in a porous medium and investigate the combined effects of microorganisms' upswimming and heating from below on the stability of bioconvection in a horizontal layer filled with a fluid saturated porous medium. Different from traditional bioconvection, thermo-bioconvection has two destabilizing mechanisms that contribute to creating the unstable density stratification. This problem may be relevant to a number of geophysical applications, such as the investigation of the dynamics of oxytactic species of thermophiles (heat loving microorganisms) living in hot springs, microbial-enhanced oil recovery, and modeling oil- and gas-bearing sedimentary basins. The utilization of the Galerkin method to solve a linear stability problem leads to a correlation between the critical value of the bioconvection Rayleigh number and the traditional “thermal” Rayleigh number.}, number={2}, journal={EUROPEAN JOURNAL OF MECHANICS B-FLUIDS}, author={Kuznetsov, AV}, year={2006}, pages={223–233} }
@article{kuznetsov_nield_2006, title={Thermally developing forced convection in a bidisperse porous medium}, volume={9}, DOI={10.1615/jpormedia.v9.i5.10}, abstractNote={The classical Graetz methodology is applied to investigate the thermal development of forced convection in a parallel-plate channel filled by a saturated bidispersed porous medium, with walls held at constant temperature. A two-velocity two-temperature model is employed for the porous medium. The analysis leads to an expression for the local Nusselt number as a function of the dimensionless longitudinal coordinate and parameters characterizing the porous medium (macropore volume fraction, interphase heat transfer parameter, thermal conductivity ratio, and effective permeability ratio).}, number={5}, journal={Journal of Porous Media}, author={Kuznetsov, A. V. and Nield, D. A.}, year={2006}, pages={393–402} }
@article{kuznetsov_2006, title={Thermo-bio-convection in porous media}, volume={9}, ISSN={["1934-0508"]}, DOI={10.1615/JPorMedia.v9.i6.60}, number={6}, journal={JOURNAL OF POROUS MEDIA}, author={Kuznetsov, A. V.}, year={2006}, pages={581–589} }
@article{fomin_hashida_chugunov_kuznestov_2005, title={A borehole temperature during drilling in a fractured rock formation}, volume={48}, ISSN={["1879-2189"]}, DOI={10.1016/j.ijheatmasstransfer.2004.07.042}, abstractNote={Drilling in brittle crystalline rocks is often accompanied by a fluid loss through the finite number of the major fractures intercepting the borehole. These fractures affect the flow regime and temperature distributions in the borehole and rock formation. In this study, the problem of borehole temperature variation during drilling of the fractured rock is analyzed analytically by applying the approximate generalized integral-balance method. The model accounts for different flow regimes in the borehole, for different drilling velocities, for different locations of the major fractures intersecting the borehole, and for the thermal history of the borehole exploitation, which may include a finite number of circulation and shut-in periods. Normally the temperature fields in the well and surrounding rocks are calculated numerically by the finite difference and finite element methods or analytically, utilizing the Laplace-transform method. The formulae obtained by the Laplace-transform method are usually complex and require tedious numerical evaluations. Moreover, in the previous research the heat interactions of circulating fluid with the rock formation were treated assuming constant bore-face temperatures. In the present study the temperature field in the formation disturbed by the heat flow from the borehole is modeled by the heat conduction equation. The thermal interaction of the circulating fluid with the formation is approximated by utilizing the Newton law of cooling at the bore-face. The discrete sinks of fluid on the bore-face model the fluid loss in the borehole through the fractures. The heat conduction problem in the rock is solved analytically by the heat balance integral method. It can be proved theoretically that the approximate solution found by this method is accurate enough to model thermal interactions between the borehole fluid and the surrounding rocks. Due to its simplicity and accuracy, the derived solution is convenient for the geophysical practitioners and can be readily used, for instance, for predicting the equilibrium formation temperatures.}, number={2}, journal={INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER}, author={Fomin, S and Hashida, T and Chugunov, V and Kuznestov, AV}, year={2005}, month={Jan}, pages={385–394} }
@article{nield_kuznetsov_2005, title={A two-velocity two-temperature model for a bi-dispersed porous medium: Forced convection in a channel}, volume={59}, ISSN={["0169-3913"]}, DOI={10.1007/s11242-004-1685-y}, number={3}, journal={TRANSPORT IN POROUS MEDIA}, author={Nield, DA and Kuznetsov, AV}, year={2005}, month={Jun}, pages={325–339} }
@article{wan_roberts_kuznetsov_2005, title={Computational analysis of the feasibility of a micro-pulsejet}, volume={32}, ISSN={["1879-0178"]}, DOI={10.1016/j.icheatmasstransfer.2004.05.020}, abstractNote={This paper investigates the feasibility of a 2-cm micro-pulsejet by numerically simulating the inviscid gas dynamic phenomena within the exhaust tube and comparing them with those for a pulsejet on the order of 50 cm in length. After initial combustion, the pressure wave propagates towards the exit and reflects back as a rarefaction wave, which generates a minimum pressure in the combustion chamber. This low pressure must be sufficient to open the reed valves to allow fresh reactants to enter. It is shown that for both large and micro-pulsejets, the minimum pressure is low enough. The characteristic operating frequency is found to be approximately inversely proportional to the pulsejet length. Estimation of the boundary layer thickness in the pulsejet shows that viscosity plays a very significant role in the micro-pulsejet and cannot be neglected.}, number={1-2}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Wan, Q and Roberts, WL and Kuznetsov, AV}, year={2005}, month={Jan}, pages={19–26} }
@article{kuznetsov_avramenko_2005, title={Effect of fouling on stability of bioconvection of gyrotactic microorganisms in a porous medium}, volume={8}, ISSN={["1934-0508"]}, DOI={10.1615/JPorMedia.v8.i1.40}, abstractNote={The main objective of this article is to investigate the effect of fouling on the stability of a uniform suspension of gyrotactic motile microorganisms in a fluid-saturated porous medium. Fouling occurs because of the deposition of microorganisms on a porous matrix. This deposition decreases porosity and permeability of the porous medium. Stability analysis carried out in this article reveals that there is a critical porosity of the porous medium. If the porous medium utilized for this process has a smaller porosity than critical, the uniform suspension of gyrotactic microorganisms is stable and bioconvection does not develop. If the porous medium has larger porosity than critical, the uniform suspension is unstable and bioconvection develops. In this article, a combination of analytical and numerical methods is utilized to solve this problem. First, a linear stability analysis is carried out analytically. Then, at the final stage of the research, numerical methods are utilized to compute the critical Darcy number.}, number={1}, journal={JOURNAL OF POROUS MEDIA}, author={Kuznetsov, AV and Avramenko, AA}, year={2005}, pages={45–53} }
@article{zhu_kuznetsov_2005, title={Forced convection in a composite parallel plate channel: modeling the effect of interface roughness and turbulence utilizing a kappa-epsilon model}, volume={32}, ISSN={["1879-0178"]}, DOI={10.1016/j.icheatmasstransfer.2004.05.019}, abstractNote={In this paper, a composite parallel plate channel whose central part is occupied by a clear fluid and whose peripheral part is occupied by a fluid-saturated porous medium is considered. The modeling is based on the assumption that the flow in the clear fluid region is turbulent while in the porous region the flow remains laminar. The turbulent and laminar flow solutions are matched at the porous/fluid interface, which is assumed rough. Two different models are utilized for calculating turbulent viscosity in the clear fluid region, the algebraic Cebeci–Smith model and a k–ε model. Numerical results obtained utilizing both models are compared and analyzed in detail.}, number={1-2}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Zhu, J and Kuznetsov, AV}, year={2005}, month={Jan}, pages={10–18} }
@article{wan_wu_chastain_roberts_kuznetsov_ro_2005, title={Forced convective cooling via acoustic streaming in a narrow channel established by a vibrating piezoelectric bimorph}, volume={74}, ISSN={["1573-1987"]}, DOI={10.1007/s10494-005-4132-4}, abstractNote={Forced convection in a narrow channel is investigated both numerically and experimentally. The flow field is established through the mechanism of acoustic streaming. This is accomplished by high frequency vibration of one of the channel walls, which is composed of a piezoelectric bimorph. In the numerical computations, the Navier-Stokes equations are decomposed into the acoustic equations and the streaming equations by the perturbation method. The acoustic field is first numerically obtained, which provides the driving force for the streaming field. The streaming field and the associated temperature field are then obtained numerically. Heat losses from a heat source are measured to determine the efficiency of this as a cooling method. The air-flow patterns in the channel between the heat source and the bimorph actuator are visualized using the particle tracking velocimetry. The visualization clearly shows that vortical streaming (acoustic streaming) can be induced by bimorph vibration, which enhances heat transfer between the heat source and the surrounding air. The temperature decreases obtained computationally and experimentally are in good agreement.}, number={2}, journal={FLOW TURBULENCE AND COMBUSTION}, author={Wan, Q and Wu, T and Chastain, J and Roberts, WL and Kuznetsov, AV and Ro, PI}, year={2005}, month={Mar}, pages={195–206} }
@article{cheng_kuznetsov_2005, title={Heat transfer in a laminar flow in a helical pipe filled with a fluid saturated porous medium}, volume={44}, ISSN={["1778-4166"]}, DOI={10.1016/j.ijthermalsci.2004.12.009}, abstractNote={This paper presents the first attempt to investigate numerically heat transfer in a helical pipe filled with a fluid saturated porous medium; the analysis is based on the full momentum equation for porous media that accounts for the Brinkman and Forchheimer extensions of the Darcy law as well as for the flow inertia. Numerical computations are performed in an orthogonal helical coordinate system. The effects of the Darcy number, the Forchheimer coefficient as well as the Dean and Germano numbers on the axial flow velocity, secondary flow, temperature distribution, and the Nusselt number are investigated.}, number={8}, journal={INTERNATIONAL JOURNAL OF THERMAL SCIENCES}, author={Cheng, LP and Kuznetsov, AV}, year={2005}, month={Aug}, pages={787–798} }
@article{wan_kuznetsov_2005, title={Investigation of hysteresis in acoustically driven channel flow at ultrasonic frequency}, volume={47}, ISSN={["1521-0634"]}, DOI={10.1080/1047780590885873}, number={2}, journal={NUMERICAL HEAT TRANSFER PART A-APPLICATIONS}, author={Wan, Q and Kuznetsov, AV}, year={2005}, month={Jan}, pages={137–146} }
@article{cheng_kuznetsov_2005, title={Investigation of laminar flow in a helical pipe filled with a fluid saturated porous medium}, volume={24}, ISSN={["1873-7390"]}, DOI={10.1016/j.euromechflu.2004.08.002}, abstractNote={Laminar flow in a helical pipe filled with a fluid saturated porous medium is investigated numerically. The analysis is based on a full momentum equation for the flow in porous media that accounts for the Brinkman and Forchheimer extensions of the Darcy law as well as for the flow inertia. Accounting for the flow inertia is shown to be important for predicting secondary flow in a helical pipe. The effects of the Darcy number, the Forchheimer coefficient as well as the curvature and torsion of the helical pipe on the axial flow velocity and secondary flow are investigated numerically.}, number={3}, journal={EUROPEAN JOURNAL OF MECHANICS B-FLUIDS}, author={Cheng, L and Kuznetsov, AV}, year={2005}, pages={338–352} }
@article{avramenko_kuznetsov_basok_blinov_2005, title={Investigation of stability of a laminar flow in a parallel-plate channel filled with a fluid saturated porous medium}, volume={17}, ISSN={["1089-7666"]}, DOI={10.1063/1.2041607}, abstractNote={Instability of a laminar flow in a parallel-plate channel filled with a fluid saturated porous medium is investigated on the basis of a modified Orr-Sommerfeld equation. This equation takes into account three drag terms: the Darcy term that describes friction between the fluid and the porous matrix, the Forchheimer quadratic drag term that describes a form drag due to the solid obstacles, and the Brinkman term, which is a viscous term similar to the Laplacian term in the Navier-Stokes equations. Numerical analysis is carried out using the collocation method. The dependence of the critical Reynolds number on porosity and permeability of the porous medium is analyzed numerically.}, number={9}, journal={PHYSICS OF FLUIDS}, author={Avramenko, AA and Kuznetsov, AV and Basok, BI and Blinov, DG}, year={2005}, month={Sep} }
@article{kuznetsov_2005, title={Investigation of the onset of thermo-bioconvection in a suspension of oxytactic microorganisms in a shallow fluid layer heated from below}, volume={19}, ISSN={["1432-2250"]}, DOI={10.1007/s00162-005-0167-3}, number={4}, journal={THEORETICAL AND COMPUTATIONAL FLUID DYNAMICS}, author={Kuznetsov, AV}, year={2005}, month={Oct}, pages={287–299} }
@article{avramenko_kuznetsov_2005, title={Linear instability analysis of a suspension of oxytactic bacteria in superimposed fluid and porous layers}, volume={61}, ISSN={["1573-1634"]}, DOI={10.1007/s11242-004-7462-0}, number={2}, journal={TRANSPORT IN POROUS MEDIA}, author={Avramenko, AA and Kuznetsov, AV}, year={2005}, month={Nov}, pages={157–175} }
@article{cheng_kuznetsov_sandeep_2005, title={Mathematical modelling of two-phase non-Newtonian flow in a helical pipe}, volume={48}, ISSN={["1097-0363"]}, DOI={10.1002/fld.950}, abstractNote={Governing equations for a two‐phase 3D helical pipe flow of a non‐Newtonian fluid with large particles are derived in an orthogonal helical coordinate system. The Lagrangian approach is utilized to model solid particle trajectories. The interaction between solid particles and the fluid that carries them is accounted for by a source term in the momentum equation for the fluid. The force‐coupling method (FCM), developed by M.R. Maxey and his group, is adopted; in this method the momentum source term is no longer a Dirac delta function but is spread on a numerical mesh by using a finite‐sized envelop with a spherical Gaussian distribution. The influence of inter‐particle and particle–wall collisions is also taken into account. Copyright © 2005 John Wiley & Sons, Ltd.}, number={6}, journal={INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS}, author={Cheng, L and Kuznetsov, AV and Sandeep, KP}, year={2005}, month={Jun}, pages={649–670} }
@article{chitrphiromsri_kuznetsov_2005, title={Modeling heat and moisture transport in firefighter protective clothing during flash fire exposure}, volume={41}, ISSN={["1432-1181"]}, DOI={10.1007/s00231-004-0504-x}, number={3}, journal={HEAT AND MASS TRANSFER}, author={Chitrphiromsri, P and Kuznetsov, A}, year={2005}, month={Jan}, pages={206–215} }
@article{chitrphiromsri_kuznetsov_2005, title={Porous medium model for investigating transient heat and moisture transport in firefighter protective clothing under high-intensity thermal exposure}, volume={8}, DOI={10.1615/jpormedia.v8.i5.80}, abstractNote={The aim of this study is to understand the performance of firefighter protective clothing in preventing thermal injury of skin that may result from exposure to high-intensity thermal radiation. A mathematical model is developed to study transient heat and moisture transport through multilayer fabric assemblies. The model accounts for changes in thermophysical and transport properties of the fabric due to the presence of moisture. Numerical simulations are performed to study heat and moisture transport in wet fabrics that are subjected to intensive flash fire exposure. The numerical solutions are further analyzed to provide a detailed physical understanding of the transport processes. Moisture in the fabric tends to vaporize starting from the outside surface of the fabric to the inside surface of the fabric during heating, and then part of it recondenses in the interior of the fabric during the cooldown. It is observed that the temperature distribution in the fabric layers and the total heat flux to the skin are significantly influenced by the amount and distribution of the moisture in the protective clothing.}, number={5}, journal={Journal of Porous Media}, author={Chitrphiromsri, P. and Kuznetsov, A. V.}, year={2005}, pages={511–528} }
@article{geng_kuznetsov_2005, title={Settling of bidispersed small solid particles in a dilute suspension containing gyrotactic micro-organisms}, volume={43}, ISSN={["1879-2197"]}, DOI={10.1016/j.ijengsci.2005.03.002}, abstractNote={The motivation of this research is to investigate the feasibility of utilizing bioconvection for enhancing mixing in a suspension of small solid particles. This may be important in micro-fluidic applications relevant to biotechnology and medicine, such as analyses of DNA or drugs, screening of patients, and combinatorial synthesis. Traditionally, the mixing of fluids in micro-volumes has been limited to diffusion. Due to the microscopic size of the organisms involved in bioconvection, bioconvective flows are a prospective and novel alternative for micro-fluidic mixing. This paper considers a bidispersed suspension of small solid particles that have different densities and settling velocities in a fluid that contains motile gyrotactic micro-organisms. The particles are assumed to be sufficiently small so that their Brownian diffusion is not negligible. It is found that the number density distribution of solid particles of one type impacts that of particles of the other type as well as that of micro-organisms.}, number={11-12}, journal={INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE}, author={Geng, P and Kuznetsov, AV}, year={2005}, month={Jul}, pages={992–1010} }
@article{kuznetsov_geng_2005, title={The interaction of bioconvection caused by gyrotactic micro-organisms and settling of small solid particles}, volume={15}, DOI={10.1108/0961550510590597}, number={4}, journal={International Journal of Numerical Methods for Heat & Fluid Flow}, author={Kuznetsov, A. V. and Geng, P.}, year={2005}, pages={328–347} }
@article{kuznetsov_2005, title={The onset of bioconvection in a suspension of gyrotactic microorganisms in a fluid layer of finite depth heated from below}, volume={32}, ISSN={["1879-0178"]}, DOI={10.1016/j.icheatmasstransfer.2004.10.021}, abstractNote={The aim of this paper is to investigate the effect of heating from below on the stability of a suspension of motile gyrotactic microorganisms in a fluid layer of finite depth. This problem is relevant to a number of geophysical applications, such as investigation of the dynamics of some species of thermophiles (heat-loving microorganisms) living in hot springs. It is established that heating from below makes the system more unstable and helps the development of bioconvection. By performing a linear stability analysis, a correlation for the critical bioconvection Rayleigh number is obtained.}, number={5}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Kuznetsov, AV}, year={2005}, month={Apr}, pages={574–582} }
@article{kuznetsov_2005, title={The onset of bioconvection in a suspension of negatively geotactic microorganisms with high-frequency vertical vibration}, volume={32}, ISSN={["1879-0178"]}, DOI={10.1016/j.icheatmasstransfer.2005.05.004}, abstractNote={The effect of vertical vibration on the stability of a dilute suspension of negatively geotactic microorganisms in a fluid layer of finite depth is investigated. For the case of high-frequency vibration, solutions of governing equations are decomposed into two components: one which varies slowly with time and a second which varies rapidly with time. An averaging method is utilized to derive the equations describing the mean flow. Linear stability analysis is used to investigate stability of the obtained averaged equations.}, number={9}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Kuznetsov, A}, year={2005}, month={Oct}, pages={1119–1127} }
@article{nield_kuznetsov_2005, title={Thermal development of forced convection in a channel or duct partly occupied by a porous medium}, volume={8}, ISSN={["1091-028X"]}, DOI={10.1615/JPorMedia.v8.i6.70}, number={6}, journal={JOURNAL OF POROUS MEDIA}, author={Nield, DA and Kuznetsov, AV}, year={2005}, pages={627–638} }
@article{nield_kuznetsov_2005, title={Thermally developing forced convection in a channel occupied by a porous medium saturated by a non-Newtonian fluid}, volume={48}, ISSN={["1879-2189"]}, DOI={10.1016/j.ijheatmasstransfer.2004.09.040}, abstractNote={The classical Graetz methodology is applied to investigate the thermal development of forced convection in a parallel plate channel filled by a saturated porous medium, with walls held at constant temperature, for the case of a non-Newtonian fluid of power-law type. A Brinkman-Forchheimer model is used for the momentum equation. The analysis for the case of small modified Darcy number leads to expressions for the local Nusselt number and average Nusselt number as functions of the dimensionless longitudinal coordinate, the power-law index, a modified Darcy number, and a modified Reynolds-Forchheimer number (with the last three parameters being involved via a boundary-layer thickness).}, number={6}, journal={INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER}, author={Nield, DA and Kuznetsov, A}, year={2005}, month={Mar}, pages={1214–1218} }
@article{kuznetsov_2005, title={Thermo-bioconvection in a suspension of oxytactic bacteria}, volume={32}, ISSN={["1879-0178"]}, DOI={10.1016/j.icheatmasstransfer.2004.11.005}, abstractNote={This paper studies thermo-bioconvection, a macroscopic convective motion induced in a fluid layer by the combined effect of density stratification caused by the upswimming of oxytactic microorganisms and heating from below. Both agencies affecting the density are destabilizing; therefore, monotonic instability is expected. Oscillatory instability may be possible in the case of cooling from below.}, number={8}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Kuznetsov, AV}, year={2005}, month={Aug}, pages={991–999} }
@article{kuznetsov_avramenko_geng_2004, title={Analytical investigation of a falling plume caused by bioconvection of oxytactic bacteria in a fluid saturated porous medium}, volume={42}, DOI={10.1016/j.ijengsci.2003.08.004}, abstractNote={The objective of this paper is to investigate theoretically a falling bioconvection plume in a deep chamber filled with a fluid saturated porous medium. The plume may be caused by oxytactic bacteria, such as Bacillus subtilis. The plume transports oxygen from the upper boundary layer, which is rich in cells and oxygen, to the lower part of the chamber, which is depleted of both cells and oxygen. A similarity solution of full governing equations (without utilizing the boundary layer approximation) that describe fluid flow as well as oxygen and cell transport in the plume is obtained. The resulting ordinary differential equations are singular when the similarity variable approaches zero; therefore, a series solution of these ordinary differential equations, which is valid for small values of the similarity variable, is obtained. This series solution is used as a starting point for a numerical solution which makes it possible to investigate the plume for the whole range of values of the similarity variable.}, number={06-May}, journal={International Journal of Engineering Science}, author={Kuznetsov, A. V. and Avramenko, A. A. and Geng, P.}, year={2004}, pages={557–569} }
@article{kuznetsov_avramenko_2004, title={Effect of small particles on the stability of bioconvection in a suspension of gyrotactic microorganisms in a layer of finite depth}, volume={31}, ISSN={["0735-1933"]}, DOI={10.1016/s0735-1933(03)00196-9}, abstractNote={An analysis of the bioconvective slump point flow of nanofluid is addressed. The studied nanofluid, which contains gyrotactic microorganisms, was investigated in a porous medium on a nonlinear tensile plate in which it was placed. The scaling group transformation approach converted the analyzed PDEs to ODEs. ODEs obtained are solved using the numerical method (rkf-45) and AGM, and the results are compared with DTM and RKF methods. The accuracy of the obtained answers is remarkable compared to the mentioned methods. An increase in the density of motile microorganism distribution caused by the increment in values of bioconvection Peclet number is desired. In addition, a rapid increase in heat transfer rate and mass transfer rate happens when there is an increase in the thermophoresis parameter, heat source parameter, chemical reaction parameter, and Brownian motion parameter in a sequence. In this study, we investigated the SPF of bioconvective nanofluids containing GM. It is observed that the flow velocity increases as Da−1 decreases. As Rb increases, bioconvection increases. These studies may be used for biotechnological applications, such as the design of bioconjugates or the increase of mass transfer in microfluidics.}, number={1}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Kuznetsov, AV and Avramenko, AA}, year={2004}, month={Jan}, pages={1–10} }
@article{geng_kuznetsov_2004, title={Effect of small solid particles on the development of bioconvection plumes}, volume={31}, ISSN={["0735-1933"]}, DOI={10.1016/S0735-1933(04)00050-8}, abstractNote={We investigate numerically the impact of small solid particles on the steady-state bioconvection plume caused by up-swimming of motile gyrotactic micro-organisms. Small solid particles that are heavier than water are added into the upper fluid layer when bioconvection has already attained its steady-state. As sedimentation process goes on, solid particles get involved in convection. They impact the fluid flow and cause the transition of the bioconvection plume to a different steady-state}, number={5}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Geng, P and Kuznetsov, AV}, year={2004}, month={Jul}, pages={629–638} }
@article{kuznetsov_becker_2004, title={Effect of the interface roughness on turbulent convective heat transfer in a composite porous/fluid duct}, volume={31}, ISSN={["0735-1933"]}, DOI={10.1016/s0735-1933(03)00197-0}, abstractNote={Flow over a finite porous medium is investigated using different interfacial conditions. In such configuration, a macroscopic interface is identified between the two media. In the first model, no diffusion-flux is considered when treating the statistical energy balance at the interface. The second approach assumes that diffusion fluxes of turbulent kinetic energy on both sides of the interface are unequal. Comparing these two models, this paper presents numerical solutions for such hybrid medium, considering here a channel partially filled with a porous layer through which fluid flows in turbulent regime. One unique set of transport equations is applied to both regions. Effects of Reynolds number, porosity, permeability and jump coefficient on mean and turbulence fields are investigated. Results indicate that depending on the value of the stress jump parameter, substantially dissimilar fields for the turbulence energy are obtained. Negative values for the stress jump parameter give results closer to experimental data for the turbulent kinetic energy at the interface.}, number={1}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Kuznetsov, AV and Becker, SM}, year={2004}, month={Jan}, pages={11–20} }
@article{kuznetsov_2004, title={Effect of turbulence on forced convection in a composite tube partly filled with a porous medium}, volume={7}, ISSN={["1934-0508"]}, DOI={10.1615/JPorMedia.v7.i1.60}, number={1}, journal={JOURNAL OF POROUS MEDIA}, author={Kuznetsov, AV}, year={2004}, pages={59–64} }
@article{nield_kuznetsov_xiong_2004, title={Effects of viscous dissipation and flow work on forced convection in a channel filled by a saturated porous medium}, volume={56}, ISSN={["0169-3913"]}, DOI={10.1023/B:TIPM.0000026087.77213.c8}, number={3}, journal={TRANSPORT IN POROUS MEDIA}, author={Nield, DA and Kuznetsov, AV and Xiong, M}, year={2004}, month={Sep}, pages={351–367} }
@article{nield_kuznetsov_2004, title={Forced convection in a bi-disperse porous medium channel: a conjugate problem}, volume={47}, ISSN={["1879-2189"]}, DOI={10.1016/j.ijheatmasstransfer.2004.07.018}, abstractNote={Forced convection in a plane channel filled with a saturated bi-disperse porous medium, coupled with conduction in plane slabs bounding the channel, is investigated analytically on the basis of a two-velocity, two-temperature model. It is found that the effect of the finite thermal resistance due to the slabs is to reduce both the heat transfer to the porous medium and the degree of local thermal non-equilibrium. An increase in value of the Péclet number leads to a decrease in the rate of exponential decay in the downstream direction but does not affect the value of a suitably defined Nusselt number. The dependence of Nusselt number on Biot number associated with the boundary slabs, the interphase heat exchange parameter, the interphase thermal conductivity ratio, the interphase effective permeability ratio, and the macroscopic void fraction, is investigated.}, number={24}, journal={INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER}, author={Nield, DA and Kuznetsov, AV}, year={2004}, month={Nov}, pages={5375–5380} }
@article{nield_kuznetsov_2004, title={Forced convection in a helical pipe filled with a saturated porous medium}, volume={47}, ISSN={["1879-2189"]}, DOI={10.1016/j.ijheatmasstransfer.2004.07.015}, abstractNote={An analysis is made of laminar forced convection in a helical pipe of circular cross-section and filled by a porous medium saturated with a fluid, for the case when the curvature and torsion of the pipe are both small. The Darcy model is employed, and boundaries with either uniform flux or uniform temperature are considered. It is found that curvature induces a secondary flow at first order in the parameter ε = κa, where κ is the curvature and a is the radius of the pipe. On the other hand, the Nusselt number is unchanged to first order in ε but is increased at second order, for either set of thermal boundary conditions. The effect of torsion on the velocity appears at second order, but torsion does not affect the Nusselt number at second order.}, number={24}, journal={INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER}, author={Nield, DA and Kuznetsov, AV}, year={2004}, month={Nov}, pages={5175–5180} }
@article{wan_kuznetsov_2004, title={INVESTIGATION OF HYSTERESIS IN ACOUSTICALLY DRIVEN CHANNEL FLOW AT ULTRASONIC FREQUENCY}, volume={47}, ISSN={1040-7782 1521-0634}, url={http://dx.doi.org/10.1080/10407780590885873}, DOI={10.1080/10407780590885873}, abstractNote={ABSTRACT The purpose of this article is to investigate the hysteresis phenomenon in the acoustic streaming flow in a channel. The channel is bounded by one stationary beam and one beam vibrating in a standing wave form. According to Wan and Kuznetsov [1-2], the acoustic streaming within the channel is driven by the slip velocity at the edge of the acoustic boundary layer near the vibrating beam. The streaming flow exhibits two different types of flow patterns at small and large channel widths. In this article, a transition between these two flow patterns and the corresponding jump in the Nusselt number as the channel width changes is investigated. As a result of extensive numerical investigations, a hysteretic region is discovered. When the channel width falls into the hysteresis region, the flow pattern and the heat transfer efficiency depends on whether the channel width is increasing or decreasing. Outside the hysteresis region, such dependence does not exist.}, number={2}, journal={Numerical Heat Transfer, Part A: Applications}, publisher={Informa UK Limited}, author={Wan, Qun and Kuznetsov, A. V.}, year={2004}, month={Dec}, pages={137–146} }
@article{nield_kuznetsov_2004, title={Interaction of transverse heterogeneity and thermal development of forced convection in a porous medium}, volume={57}, ISSN={["1573-1634"]}, DOI={10.1023/B:TIPM.0000032701.17429.97}, number={1}, journal={TRANSPORT IN POROUS MEDIA}, author={Nield, DA and Kuznetsov, AV}, year={2004}, month={Oct}, pages={103–111} }
@article{wan_kuznetsov_2004, title={Investigation of the acoustic streaming in a rectangular cavity induced by the vibration of its lid}, volume={31}, ISSN={["0735-1933"]}, DOI={10.1016/S0735-1933(04)00028-4}, abstractNote={In this paper, the Network Simulation Method (NSM) is used to model an unsteady, viscous, flow problem: the heated lid-driven filled with nanofluid and in the presence of a pulsating flow. Through this method is analyzed the influence of the amplitude, wave number and oscillation frequency of sinusoidal velocity waves at the lid on the convection performance of the cavity. It is stated that this method is simple and efficient for solving unsteady, viscous, Navier–Stokes equations, through the design and resolution of an electrical circuit network whose equations are formally equivalent to the ones of the fluid flow problem. Results show that, for the case of Pr = 3.93, Re = 50, Ri = 11.82, sinusoidal velocity waves at the lid increase the time-averaged Nusselt number in the cavity with respect to the non-pulsating case up to a 16%. This is due to enhancement of the transport phenomena induced by the pulsating flow.}, number={4}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Wan, Q and Kuznetsov, AV}, year={2004}, month={May}, pages={467–476} }
@article{avramenko_kobzar_shevchuk_kuznetsov_basok_2004, title={Laminar forced convection in curved channel with vortex structures}, volume={21}, DOI={10.1515/tjj.2004.21.1.19}, abstractNote={AbstractTheoretical and experimental investigations of heat transfer in flat curvilinear channel have been carried out. Linear and non-linear effects of Dean vortexes on intensity of heat transfer were taken into account. The linear effect, which describe harmonic (sinuous) variation of the heat transfer coefficient near the concave surface of the channel and the non-linear effect causes the general increase of the heat transfer coefficient due to augmentation of heat transfer engendered by the Dean vortexes. For both effects, mathematical relations were obtained in the form of quadratures. These numerical results were modified to the form convenient in engineering calculations. The investigations have shown that both linear and nonlinear components grow up with the Dean number. Nonlinear component
$$Q\frac{T}{0}$$
increases more abruptly, while the linear one
$$Q\frac{T}{1}$$
is more conservative. This is a confirmation of stability of vortex structures.}, number={1}, journal={International Journal of Turbo & Jet. Engines}, author={Avramenko, A. A. and Kobzar, S. G. and Shevchuk, I. V. and Kuznetsov, A. V. and Basok, B. I.}, year={2004}, pages={19–28} }
@article{avramenko_kobzar_shevchuk_kuznetsov_basok_2004, title={Laminar forced convection in curved channel with vortex structures}, volume={13}, ISSN={1003-2169 1993-033X}, url={http://dx.doi.org/10.1007/s11630-004-0023-6}, DOI={10.1007/s11630-004-0023-6}, number={2}, journal={Journal of Thermal Science}, publisher={Springer Science and Business Media LLC}, author={Avramenko, A. A. and Kobzar, S. G. and Shevchuk, I. V. and Kuznetsov, A. V. and Basok, B. I.}, year={2004}, month={May}, pages={143–150} }
@article{song_barker_hamouda_kuznetsov_chitrphiromsri_grimes_2004, title={Modeling the thermal protective performance of heat resistant garments in flash fire exposures}, volume={74}, ISSN={["0040-5175"]}, DOI={10.1177/004051750407401201}, abstractNote={ This research developes a numerical model to predict skin burn injury resulting from heat transfer through a protective garment worn by an instrumented manikin exposed to laboratory-controlled flash fire exposures. This model incorporates characteristics of the simulated flash fire generated in the chamber and the heat-induced changes in fabric thermophysical properties. The model also accounts for clothing air layers between the garment and the manikin. The model is validated using an instrumented manikin fire test system. Results from the numerical model help contribute to a better understanding of the heat transfer process in protective garments exposed to intense flash fires, and to establishing systematic methods for engineering materials and garments to produce optimum thermal protective performance. }, number={12}, journal={TEXTILE RESEARCH JOURNAL}, author={Song, GW and Barker, RL and Hamouda, H and Kuznetsov, AV and Chitrphiromsri, P and Grimes, RV}, year={2004}, month={Dec}, pages={1033–1040} }
@article{becker_kuznetsov_avramenko_2004, title={Numerical modeling of a falling bioconvection plume in a porous medium}, volume={35}, ISSN={["1873-7005"]}, DOI={10.1016/j.fluiddyn.2004.07.003}, abstractNote={This paper considers a bioconvection plume in a fluid saturated porous medium. Bioconvection plumes may arise as a result of an unstable density stratification caused by up-swimming microorganisms. This unstable density stratification occurs when the microorganisms, heavier than water, accumulate in the upper regions of the fluid. The plume transports cells and oxygen from the upper fluid region to the lower fluid regions. This paper finds a numerical solution for the steady-state plume in a porous medium by utilizing an implicit finite difference method. The effects of varying pertinent parameters are investigated. A similarity solution of the plume is also obtained for comparison purposes.}, number={5}, journal={FLUID DYNAMICS RESEARCH}, author={Becker, SM and Kuznetsov, AV and Avramenko, AA}, year={2004}, month={Nov}, pages={323–339} }
@article{kuznetsov_2004, title={Numerical modeling of turbulent flow in a composite porous/fluid duct utilizing a two-layer k-epsilon model to account for interface roughness}, volume={43}, ISSN={["1778-4166"]}, DOI={10.1016/j.ijthermalsci.2004.02.011}, abstractNote={This paper is aimed at investigating the effect of roughness of the porous/fluid interface on turbulent convection heat transfer in composite porous/fluid ducts. It is expected that in many cases the effect of interface roughness on convection may be more significant than the effect of possible flow turbulization in the porous region. The analysis of appropriate dimensionless parameters shows that in many practical situations even if the flow in the clear fluid region is turbulent, the flow in the porous region remains laminar. The problem is thus reduced to matching the turbulent flow solution in the clear fluid region with the laminar flow solution in the porous region at the rough interface. It is shown that roughness of the porous/fluid interface significantly impacts turbulent flow in the clear fluid region as well as overall heat transfer in the duct.}, number={11}, journal={INTERNATIONAL JOURNAL OF THERMAL SCIENCES}, author={Kuznetsov, A}, year={2004}, month={Nov}, pages={1047–1056} }
@article{avramenko_kuznetsov_2004, title={Stability of a suspension of gyrotactic microorganisms in superimposed fluid and porous layers}, volume={31}, ISSN={["0735-1933"]}, DOI={10.1016/j.icheatmasstransfer.2004.08.003}, abstractNote={The aim of this paper is to investigate the stability of a suspension of motile gyrotactic microorganisms in a system that consists of superimposed fluid and porous layers. This is relevant to many biological applications, such as growing motile microorganisms in Petri dishes. By performing a linear stability analysis a correlation for the critical Rayleigh number is obtained.}, number={8}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Avramenko, AA and Kuznetsov, AV}, year={2004}, month={Nov}, pages={1057–1066} }
@article{wan_kuznetsov_2004, title={Streaming in a channel bounded by an ultrasonically oscillating beam and its cooling efficiency}, volume={45}, ISSN={["1040-7782"]}, DOI={10.1080/1040778049026739}, abstractNote={In this article the oscillating and streaming flow fields in a channel composed of two long parallel beams, one of which is stationary and the other of which oscillates with an ultrasonic frequency in a standing wave form, are investigated. The perturbation technique is utilized under the assumption that the oscillation amplitude is much smaller than the channel width and that the Reynolds number, which is defined by the oscillating frequency and the standing wave number, is much greater than unity. A three-layer structure of both the oscillating and streaming flow fields, which is composed of two very thin boundary layers near the beams and the core region between the boundary layers, is found in the channel. The oscillating velocity fields in all three layers are obtained analytically. The streaming fields within both boundary layers are also obtained analytically based on the oscillating fields. It is found that the streaming velocities approach constant values at the edges of the boundary layers and thus provide slip velocities for the streaming field in the core region. The core-region streaming velocity field is then obtained numerically by solving the Navier–Stokes equations in the stream function–vorticity formulation. Based on the core-region streaming field, which dominates most of the channel, the temperature field is computed for two cases: both beams are kept at constant but different temperatures (case A); and the oscillating beam is kept at a constant temperature while the stationary beam is subjected to a uniform constant heat flux (case B). Cases of different channel widths are computed and a critical width is found. When the channel width is smaller than the critical one, for each half standing wavelength distance along the beams, two symmetric eddies are observed, which occupy almost the whole width of the channel. In this case, the Nusselt number increases with the increase of the channel width. After the critical width, two layers of asymmetric eddies are observed near the oscillating beam and the Nusselt number decreases and approaches unity with further increase of the channel width. The abrupt change of the streaming field and the Nusselt number as the channel width goes through its critical value may be due to a bifurcation caused by instability of the vortex structure in the fluid layer.}, number={1}, journal={NUMERICAL HEAT TRANSFER PART A-APPLICATIONS}, author={Wan, Q and Kuznetsov, AV}, year={2004}, month={Jan}, pages={21–47} }
@article{nield_kuznetsov_avramenko_2004, title={The onset of bioconvection in a horizontal porous-medium layer}, volume={54}, ISSN={["0169-3913"]}, DOI={10.1023/B:TIPM.0000003662.31212.5b}, number={3}, journal={TRANSPORT IN POROUS MEDIA}, author={Nield, DA and Kuznetsov, AV and Avramenko, AA}, year={2004}, month={Mar}, pages={335–344} }
@article{nield_kuznetsov_xiong_2004, title={Thermally developing forced convection in a porous medium: Parallel-plate channel or circular tube with isothermal walls}, volume={7}, ISSN={["1091-028X"]}, DOI={10.1615/JPorMedia.v7.i1.30}, abstractNote={The classical Graetz methodology is applied to investigate the thermal development of forced convection in a parallel-plate channel or a circular tube filled by a saturated porous medium, with walls held at constant temperature. The Brinkman model is employed. The analysis leads to expressions for the local Nusselt number and average Nusselt number, as functions of the dimensionless longitudinal coordinate and the Darcy number.}, number={1}, journal={JOURNAL OF POROUS MEDIA}, author={Nield, DA and Kuznetsov, AV and Xiong, M}, year={2004}, pages={19–27} }
@article{mao_edwards_kuznetsov_srivastava_2004, title={Three-dimensional numerical simulation of a circulating fluidized bed reactor for multi-pollutant control}, volume={59}, ISSN={["0009-2509"]}, DOI={10.1016/j.ces.2004.06.004}, abstractNote={Circulating fluidized bed adsorber (CFBA) technology is regarded as a potentially effective method for simultaneously controlling emissions of sulfur dioxide, fine particulate matter, and trace heavy metals, such as mercury vapor. In order to analyze CFBA systems in detail, a gas mixture/solids mixture model based on the three-dimensional Navier–Stokes equations is developed for particle flow, agglomeration, physical and chemical adsorption in a circulating fluidized bed. The solids mixture consists of two solids, one with components of CaO and CaSO4, and the other being an activated carbon. The gas mixture is composed of fine particulate matter (PM), sulfur dioxide, mercury vapor, oxygen and inert gas. Source terms representing fine particulate matter agglomeration onto sorbent particles, sulfur dioxide removal through chemical adsorption onto calcined lime, and mercury vapor removal through physical adsorption onto activated carbon are formulated and included into the model. The governing equations are solved using high-resolution upwind-differencing methods, combined with a time-derivative preconditioning method for efficient time-integration. Numerical simulations of bench-scale operation of a prototype CFBA reactor for multi-pollutant control are described.}, number={20}, journal={CHEMICAL ENGINEERING SCIENCE}, author={Mao, DM and Edwards, JR and Kuznetsov, AV and Srivastava, RK}, year={2004}, month={Oct}, pages={4279–4289} }
@article{kuznetsov_avramenko_geng_2003, title={A similarity solution for a falling plume in bioconvection of oxytactic bacteria in a porous medium}, volume={30}, ISSN={["0735-1933"]}, DOI={10.1016/S0735-1933(03)00005-8}, abstractNote={In this paper, a numerical investigation on mixed bioconvection flow of silver(Ag)-magnesium oxide(MgO)-water hybrid nanofluid in a trapezoidal porous cavity under the effect of inclined periodic magnetic field is carried out. Brinkman–Forchheimer-extended Darcy model for the porous medium is adopted. Galerkin weighted residual finite element method is implemented to simulate the governing steady dimensionless equations. The resulting discrete nonlinear algebraic systems are treated using the adaptive Newton's method. The fluid flow, heat and mass transfer behavior are examined in variation of parameters as Hartmann number (Ha = 0−100), angle of periodic magnetic field (θ = 0∘−90∘), period of periodic magnetic field (Λ = 0.1−1), bioconvection Rayleigh number (Rb = 10−100), Richardson number (Ri = 0.1−5), Lewis number (Le = 1−10) and Peclet number (Pe = 0.1−1). The rise in Hartmann number has a weakening effect on both transfer of heat and mass. When θ = 0∘, convective heat and mass transfer is the smallest at Λ = 1 where the most reduction in the average Nusselt and Sherwood numbers is 9.14% and 6.98% as Λ is raised from 0.1 to 1, respectively, and occurs at Ha = 100. The significant decrement in the average Nusselt number is 42.57% at Ha = 75 and in the Sherwood number is 10.4% at Ha = 50 when θ is changed from 0∘ to 90∘.}, number={1}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Kuznetsov, AV and Avramenko, AA and Geng, P}, year={2003}, month={Jan}, pages={37–46} }
@article{kuznetsov_avramenko_2003, title={Analysis of stability of bioconvection of motile oxytactic bacteria in a horizontal fluid saturated porous layer}, volume={30}, ISSN={["0735-1933"]}, DOI={10.1016/S0735-1933(03)00097-6}, abstractNote={Stability of a suspension of motile oxytactic microorganisms in a shallow layer filled with a fluid saturated porous medium is investigated. Because the layer is shallow, oxygen concentration is larger than the minimum concentration required for the bacteria to be active and the bacteria are actively swimming in the direction of maximum oxygen gradient in every location within the layer. Linear stability analysis results in the determination of the critical value of the product of Raleigh and Darcy numbers}, number={5}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Kuznetsov, AV and Avramenko, AA}, year={2003}, month={Jul}, pages={593–602} }
@article{kuznetsov_jiang_2003, title={Bioconvection of negatively geotactic microorganisms in a porous medium: the effect of cell deposition and declogging}, volume={13}, ISSN={["1758-6585"]}, DOI={10.1108/09615530310464535}, abstractNote={Mechanisms of deposition and declogging are considered while formulating a new continuum model for bioconvection in a dilute suspension of motile, negatively geotactic microorganisms in a porous medium. According to research in 1988, bioconvection is the name given to pattern‐forming convective motions set up in suspensions of swimming microorganisms. “Negative geotaxis” means that the microorganisms tend to swim against the gravitational force. This paper is motivated by experimental research by Kessler who investigated the effect of porous media on the development of convection instability in algal suspensions. In the model suggested in this paper, the decrease of permeability due to cell adsorption by the porous medium is considered and the influence of this permeability decrease on the development of bioconvection is studied. The existence and stability of a two‐dimensional plume in a rectangular enclosure with stress‐free sidewalls is investigated. Governing equations include the Darcy law as well as the microorganism conservation equations. A conservative finite‐difference scheme is utilized to solve these equations numerically. The analysis of the proposed model reveals that the major factors affecting the development of bioconvection are the initial permeability of the porous medium and the rate of cell deposition. For small permeability, the resistance to the fluid flow is too large, and bioconvection does not develop. If the rate of cell deposition is too large, the number of suspended cells quickly becomes too small because of cell capturing by the porous medium. For this reason, the critical density difference in the top fluid layer cannot be reached, and bioconvection does not develop.}, number={2-3}, journal={INTERNATIONAL JOURNAL OF NUMERICAL METHODS FOR HEAT & FLUID FLOW}, author={Kuznetsov, AV and Jiang, N}, year={2003}, pages={341–364} }
@article{nield_kuznetsov_2003, title={Boundary-layer analysis of forced convection with a plate and porous substrate}, volume={166}, ISSN={["1619-6937"]}, DOI={10.1007/s00707-003-0050-5}, number={1-4}, journal={ACTA MECHANICA}, author={Nield, DA and Kuznetsov, AV}, year={2003}, month={Dec}, pages={141–148} }
@article{kuznetsov_xiong_2003, title={Development of an engineering approach to computations of turbulent flows in composite porous/fluid domains}, volume={42}, ISSN={["1290-0729"]}, DOI={10.1016/S1290-0729(03)00063-2}, abstractNote={The purpose of this paper is to develop an engineering approach to computations of turbulent flows in composite domains partly occupied by a clear fluid and partly by a fluid saturated porous medium. Previous research concerning turbulent flows in porous media indicates that the effect of porous media is to dampen turbulence. Therefore, in porous/fluid domains the penetration depth of turbulent eddies into the porous region is expected to be small. The authors suggest assuming that the flow over the whole porous region remains laminar and matching turbulent flow solution in the clear fluid region with the laminar flow solution in the turbulent flow region. Although the flow in the porous region is assumed to be laminar, linear Darcy or Brinkman–Darcy models cannot be utilized to describe momentum transport in the porous region because of large filtration velocity. The momentum transport model in the porous layer utilized in this research is based on the Brinkman–Forchheimer-extended Darcy equation, which allows the accounting for deviation from linearity and also allows a smooth matching of the filtration velocity at the porous/fluid interface. Because of the large filtration velocity in the porous region, the energy equation in the porous region also accounts for the thermal dispersion effects.}, number={10}, journal={INTERNATIONAL JOURNAL OF THERMAL SCIENCES}, author={Kuznetsov, AV and Xiong, M}, year={2003}, month={Oct}, pages={913–919} }
@article{mao_edwards_kuznetsov_srivastava_2003, title={Development of low-diffusion flux-splitting methods for dense gas-solid flows}, volume={185}, ISSN={["1090-2716"]}, DOI={10.1016/S0021-9991(02)00049-9}, abstractNote={The development of a class of low-diffusion upwinding methods for computing dense gas-solid flows is presented in this work. An artificial compressibility/low-Mach preconditioning strategy is developed for a hyperbolic two-phase flow equation system consisting of separate solids and gas momentum and continuity equations. The eigenvalues of this system are used to devise extensions of the AUSM+ [1] and LDFSS [2] flux-splitting methods that provide high resolution capturing of bubble growth and collapse in gas-solid fluidized beds. Applications to several problems in fluidization are presented.}, number={1}, journal={JOURNAL OF COMPUTATIONAL PHYSICS}, author={Mao, DM and Edwards, JR and Kuznetsov, AV and Srivastava, RK}, year={2003}, month={Feb}, pages={100–119} }
@article{wan_kuznetsov_2003, title={Effect of non-uniformity of source vibration amplitude on the sound field wave number, attenuation coefficient and Reynolds stress for the acoustic streaming}, volume={30}, ISSN={["1879-0178"]}, DOI={10.1016/S0735-1933(03)00004-6}, abstractNote={The aim of this paper is to analytically solve the sound field generated by a standing wave induced in a vibrating beam. This case is different from a plane wave which is the traditional way of inducing acoustic streaming. The analytical solution shows that the amplitude non-uniformity can be represented by a non-uniformity coefficient y, which characterizes the ratio of the wave number or the attenuation coefficient to their values for the classical plane wave case. The non-uniformity coefficient γ is also obtained by resolving the acoustic field utilizing full numerical solution. Numerical and analytical results are in a good agreement. The Reynolds stress generated by a beam vibrating at one of its modes is also calculated. The maximum values of the Reynolds stress are achieved at the anti-node coordinates and small negative minimum values of the Reynolds stress are observed at the node coordinates. An interesting four-vortex-per-wavelength structure is predicted for such sound field.}, number={1}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Wan, Q and Kuznetsov, AV}, year={2003}, month={Jan}, pages={27–36} }
@article{nield_kuznetsov_2003, title={Effects of gross heterogeneity and anisotropy in forced convection in a porous medium: Layered medium analysis}, volume={6}, DOI={10.1615/jpormedia.v6.i1.30}, abstractNote={The effects of gross heterogeneity and anisotropy, associated with horizontal fissures in a porous medium filling a parallel-plate channel, on forced convection are studied. An approximate analysis, based on a piecewise-constant (layered) distribution of permeability across the channel, is used to model the experiments performed by Paek et al. (1999) on foam material with drilled-out tubes. The analysis leads to estimates of the Nusselt number, Nu. Drilling out the tubes leads to a reduction in the value of Nu but an even greater reduction in the friction factor, f, so that the net result is an increase in the value of Nu/f, i.e., for a given driving pressure gradient the heat transfer is increased.}, number={1}, journal={Journal of Porous Media}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2003}, pages={51–57} }
@article{nield_kuznetsov_2003, title={Effects of heterogeneity in forced convection in a porous medium: Parallel-plate channel, Brinkman model}, volume={6}, ISSN={["1934-0508"]}, DOI={10.1615/JPorMedia.v6.i4.40}, abstractNote={The effects of variation (in the transverse direction, in layers) of permeability and thermal conductivity, on fully developed forced convection in a parallel-plate channel filled with a saturated porous medium, is investigated analytically on the basis of a Brinkman model, for the case of isoflux boundaries and a two-step variation. The results demonstrate that the effect of permeability variation is that an above-average permeability near the walls leads to an increase in Nusselt number, and this is explained in terms of variation in the curvature of the temperature profile. This effect of permeability variation becomes less important as the Darcy number increases. The effect of conductivity variation is more complex; there are two opposing effects and the Nusselt number is not always a monotonic function of the conductivity variation. This effect of conductivity variation retains its importance as the Darcy number increases.}, number={4}, journal={JOURNAL OF POROUS MEDIA}, author={Nield, DA and Kuznetsov, AV}, year={2003}, pages={257–266} }
@article{nield_kuznetsov_2003, title={Effects of temperature-dependent viscosity in forced convection in a porous medium: Layered-medium analysis}, volume={6}, ISSN={["1934-0508"]}, DOI={10.1615/JPorMedia.v6.i3.60}, number={3}, journal={JOURNAL OF POROUS MEDIA}, author={Nield, DA and Kuznetsov, AV}, year={2003}, pages={213–222} }
@article{kuznetsov_cheng_xiong_2003, title={Investigation of turbulence effects on forced convection in a composite porous/fluid duct: Constant wall flux and constant wall temperature cases}, volume={39}, ISSN={["1432-1181"]}, DOI={10.1007/S00231-002-0377-9}, number={7}, journal={HEAT AND MASS TRANSFER}, author={Kuznetsov, A and Cheng, L and Xiong, M}, year={2003}, month={Jul}, pages={613–623} }
@article{wan_kuznetsov_2003, title={Numerical study of the efficiency of acoustic streaming for enhancing heat transfer between two parallel beams}, volume={70}, ISSN={["1386-6184"]}, DOI={10.1023/B:APPL.0000004916.01838.63}, number={1-4}, journal={FLOW TURBULENCE AND COMBUSTION}, author={Wan, Q and Kuznetsov, AV}, year={2003}, pages={89–114} }
@article{kim_kuznetsov_2003, title={OPTIMIZATION OF PIN-FIN HEAT SINKS USING ANISOTROPIC LOCAL THERMAL NONEQUILIBRIUM POROUS MODEL IN A JET IMPINGING CHANNEL}, volume={44}, ISSN={1040-7782 1521-0634}, url={http://dx.doi.org/10.1080/716100528}, DOI={10.1080/716100528}, abstractNote={A numerical study has been carried out to optimize the thermal performance of a pin-fin heat sink. A pin-fin heat sink, which is placed horizontally in a channel, is modeled as a hydraulically and thermally anisotropic porous medium. A uniform heat flux is prescribed at the bottom of the heat sink. Cool air is supplied from the top opening of the channel and exhausts to the channel outlet. Comprehensive numerical solutions are derived from the governing Navier-Stokes and energy equations using the Brinkman-Forchheimer extended Darcy model and the local thermal nonequilibrium (LTNE) porous model for the region occupied by the heat sink. Results from this study indicate that the anisotropy in permeability and solid-phase effective thermal conductivity changes substantially with the variation of porosity. Optimum porosity for maximum heat dissipation depends on the pin-fin thickness, the pin-fin height, and the Reynolds number. A correlation for predicting the optimum porosity for a pin-fin heat sink is proposed. Generally, in the case of thin pin-fins the heat sink should be designed to have a high porosity, while in the case of thick pin-fins the heat sink should be designed to have a relatively low porosity.}, number={8}, journal={Numerical Heat Transfer, Part A: Applications}, publisher={Informa UK Limited}, author={Kim, Seo Young and Kuznetsov, Andrey V.}, year={2003}, month={Dec}, pages={771–787} }
@article{kim_kuznetsov_2003, title={Optimization of pin-fin heat sinks using anisotropic local thermal nonequilibrium porous model in a jet impinging channel}, volume={44}, DOI={10.1080/10407780390229675}, number={8}, journal={Numerical Heat Transfer. Part A, Applications}, author={Kim, S. Y. and Kuznetsov, A. V.}, year={2003}, pages={771–787} }
@article{kuznetsov_avramenko_2003, title={Stability analysis of bioconvection of gyrotactic motile microorganisms in a fluid saturated porous medium}, volume={53}, ISSN={["0169-3913"]}, DOI={10.1023/A:1023582001592}, number={1}, journal={TRANSPORT IN POROUS MEDIA}, author={Kuznetsov, AV and Avramenko, AA}, year={2003}, month={Oct}, pages={95–104} }
@article{kuznetsov_avramenko_2003, title={The effect of deposition and declogging on the critical permeability in bioconvection in a porous medium}, volume={160}, ISSN={["0001-5970"]}, DOI={10.1007/s00707-002-0978-x}, number={1-2}, journal={ACTA MECHANICA}, author={Kuznetsov, AV and Avramenko, AA}, year={2003}, pages={113–125} }
@article{kuznetsov_xiong_nield_2003, title={Thermally developing forced convection in a porous medium: Circular duct with walls at constant temperature, with longitudinal conduction and viscous dissipation effects}, volume={53}, ISSN={["0169-3913"]}, DOI={10.1023/A:1025060524816}, number={3}, journal={TRANSPORT IN POROUS MEDIA}, author={Kuznetsov, AV and Xiong, M and Nield, DA}, year={2003}, month={Dec}, pages={331–345} }
@article{nield_kuznetsov_xiong_2003, title={Thermally developing forced convection in a porous medium: Parallel-plate channel or circular tube with walls at constant heat flux}, volume={6}, ISSN={["1091-028X"]}, DOI={10.1615/JPorMedia.v6.i3.50}, abstractNote={An adaptation of the classical Graetz methodology is applied to investigate the thermal development of forced convection in a parallel-plate channel or a circular tube filled by a saturated porous medium, with walls held at constant heat flux. The Brinkman model is employed. The analysis leads to expressions for the local Nusselt number and average Nusselt number, as functions of the dimensionless longitudinal coordinate and the Darcy number.}, number={3}, journal={JOURNAL OF POROUS MEDIA}, author={Nield, DA and Kuznetsov, AV and Xiong, M}, year={2003}, pages={203–212} }
@article{nield_kuznetsov_xiong_2003, title={Thermally developing forced convection in a porous medium: parallel plate channel with walls at uniform temperature, with axial conduction and viscous dissipation effects}, volume={46}, ISSN={["0017-9310"]}, DOI={10.1016/S0017-9310(02)00327-7}, abstractNote={A modified Graetz methodology is applied to investigate the thermal development of forced convection in a parallel plate channel filled by a saturated porous medium, with walls held at uniform temperature, and with the effects of axial conduction and viscous dissipation included. The Brinkman model is employed. The analysis leads to expressions for the local Nusselt number, as a function of the dimensionless longitudinal coordinate and other parameters (Darcy number, Péclet number, Brinkman number).}, number={4}, journal={INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER}, author={Nield, DA and Kuznetsov, AV and Xiong, M}, year={2003}, month={Feb}, pages={643–651} }
@article{kuznetsov_avramenko_2002, title={A 2D analysis of stability of bioconvection in a fluid saturated porous medium - Estimation of the critical permeability value}, volume={29}, ISSN={["0735-1933"]}, DOI={10.1016/S0735-1933(02)00308-1}, abstractNote={Abstract The main purpose of this paper is to perform a 2D stability analysis of bioconvection in a suspension of motile gyrotactic microorganisms in a fluid saturated porous medium and to obtain an analytical expression for the critical permeability of the porous medium. Recent numerical investigation by Kuznetsov and Jiang [1] suggests that permeability is a very important parameter for bioconvection in porous media. Their numerical results indicate that for small permeability bioconvection is stable (the microorganisms swim in the upward direction), while for large permeability it is unstable (variations of density are enhanced and macroscopic fluid circulation is induced). In the present investigation, a simple but elegant criterion of stability of the bioconvection is obtained. This criterion gives the critical permeability of the porous medium through the cell eccentricity, average swimming velocity, fluid viscosity, and other relevant parameters.}, number={2}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Kuznetsov, AV and Avramenko, AA}, year={2002}, month={Feb}, pages={175–184} }
@article{mao_edwards_kuznetsov_srivastava_2002, title={A model for fine particle agglomeration in circulating fluidized bed absorbers}, volume={38}, ISSN={["0947-7411"]}, DOI={10.1007/S002310100260}, number={4-5}, journal={HEAT AND MASS TRANSFER}, author={Mao, D and Edwards, JR and Kuznetsov, AV and Srivastava, R}, year={2002}, month={Apr}, pages={379–388} }
@article{kim_kim_kuznetsov_2002, title={Analysis of coupled turbulent flow and solidification in the wedge-shaped pool with different nozzles during twin-roll strip casting}, volume={41}, ISSN={["1040-7782"]}, DOI={10.1080/104077802317221410}, abstractNote={In the twin-roll continuous casting (CC) process that produces a near-net-shaped strip, the mushy zone solidification phenomena are mainly influenced by various process parameters such as nozzle shape, roll-gap thickness, and superheat of melt. This study numerically examines, in a wedge-shaped pool for the twin-roll CC process, the dependence of the solidification phenomena and melt-flow behavior on those process parameters. The turbulent characteristics of the melt flow are considered using a low-Reynolds-number k- k turbulence model. The results show that there exists the distinct region with a well-mixed melt flow and a wide range of mush in the lower part of the pool. The variation of the melt-flow velocity due to different nozzle types mainly affects the liquidus line and has little effect on the solidus line in the outlet region. In the case of a small roll gap, the liquidus line is shifted upward and the solidified shell thickness increases slightly in the outlet region. The variation of melt superheat mainly affects the position of the liquidus line. The direct melt feed onto the free surface has little effect of the melt superheat on an increase in the temperature in the lower part of the pool, while the overall temperature in the lower part of the pool for the submerged nozzle has a high dependence on the melt superheat.}, number={1}, journal={NUMERICAL HEAT TRANSFER PART A-APPLICATIONS}, author={Kim, DS and Kim, WS and Kuznetsov, AV}, year={2002}, month={Jan}, pages={1–17} }
@article{kuznetsov_xiong_2002, title={Dependence of microporosity formation on the direction of solidification}, volume={29}, ISSN={["0735-1933"]}, DOI={10.1016/S0735-1933(01)00321-9}, abstractNote={The aim of this paper is to suggest a new approach in the investigation of the effect of gravity on microporosity formation in solidification of binary alloys. Instead of traditional unidirectional solidification from the bottom, which involves solidification against the gravity, we suggest to carry out solidification from the top, which involves solidification along the gravity. Numerical modeling performed in this paper suggests an experimental study that compares the results of these two experiments, which potentially reveals some important data concerning the influence of gravity on microporosity formation and also could be used as a tool for validation of microporosity formation models.}, number={1}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Kuznetsov, AV and Xiong, M}, year={2002}, month={Jan}, pages={25–34} }
@article{kuznetsov_xiong_2002, title={Effect of evaporation on thin film deposition in dip coating process}, volume={29}, ISSN={["0735-1933"]}, DOI={10.1016/S0735-1933(01)00322-0}, abstractNote={Evaporation from the free surface is an important phenomenon that occurs during dip coating process. Accounting for evaporation is crucial for correct prediction of film thickness during this process when evaporation rate is large. This paper suggests a method to extend the classical free meniscus theory to account for evaporation from the free surface in a two-component system. The governing equations are solved utilizing a finite difference method. The effects of evaporation on the free surface profile and solute concentration distribution are investigated.}, number={1}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Kuznetsov, AV and Xiong, M}, year={2002}, month={Jan}, pages={35–44} }
@article{nield_kuznetsov_xiong_2002, title={Effect of local thermal non-equilibrium on thermally developing forced convection in a porous medium}, volume={45}, ISSN={["0017-9310"]}, DOI={10.1016/S0017-9310(02)00203-X}, abstractNote={The classical Graetz methodology is applied to investigate the effect of local thermal non-equilibrium on the thermal development of forced convection in a parallel-plate channel filled by a saturated porous medium, with walls held at constant temperature. The Brinkman model is employed. The analysis leads to an expression for the local Nusselt number, as a function of the dimensionless longitudinal coordinate, the Péclet number, the Darcy number, the solid–fluid heat exchange parameter, the solid/fluid thermal conductivity ratio, and the porosity.}, number={25}, journal={INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER}, author={Nield, DA and Kuznetsov, AV and Xiong, M}, year={2002}, month={Dec}, pages={4949–4955} }
@article{kuznetsov_cheng_xiong_2002, title={Effects of thermal dispersion and turbulence in forced convection in a composite parallel-plate channel: Investigation of constant wall heat flux and constant wall temperature cases}, volume={42}, ISSN={["1040-7782"]}, DOI={10.1080/10407780290059602}, abstractNote={In this article, a composite parallel-plate channel whose central portion is occupied by a clear fluid and whose peripheral portion is occupied by a fluid saturated porous medium, is considered. The flow in the porous region of the channel is assumed to be laminar, governed by the Brinkman-Forchheimer-extended Darcy equation, while the flow in the clear fluid region of the channel is assumed to be turbulent. The validity of this laminar/turbulent assumption is validated by estimating Reynolds numbers in the clear fluid and porous regions of the channel. Although the flow in the porous region remains laminar, it is still fast enough for the quadratic drag (Forchheimer) effects to be important. In this situation, hydrodynamic mixing of the interstitial fluid at the pore scale becomes important and may cause significant thermal dispersion. It is shown that thermal dispersion may result in some counterintuitive effects, such as the increase of the Nusselt number when the width of the clear fluid region in the center of the channel is decreased.}, number={4}, journal={NUMERICAL HEAT TRANSFER PART A-APPLICATIONS}, author={Kuznetsov, AV and Cheng, L and Xiong, M}, year={2002}, month={Sep}, pages={365–383} }
@article{mao_edwards_kuznetsov_srivastava_2002, title={Particle flow, mixing, and chemical reaction in circulating fluidized bed absorbers}, volume={57}, ISSN={["0009-2509"]}, DOI={10.1016/S0009-2509(02)00168-9}, abstractNote={Abstract A mixing model has been developed to simulate the particle residence time distribution (RTD) in a circulating fluidized bed absorber (CFBA). Also, a gas/solid reaction model for sulfur dioxide (SO 2 ) removal by lime has been developed. For the reaction model that considers RTD distribution inside the core and annulus regions of a CFBA, a macrochemical reaction can be simulated based on microchemical reaction dynamics. The presented model can predict SO 2 and lime concentration distributions inside the CFBA, and give the amount of lime needed to remove a given percentage of SO 2 . It is found that SO 2 concentration decreases with the increase of CFBA distance from the bottom in the core region. However, lime concentration exhibits a very slight variation in the core region. This means that lime is efficiently utilized to remove SO 2 . The model also predicts that SO 2 partial pressure at the exit of the CFBA decreases with the increase in the percentage of fresh lime injected in the CFBA.}, number={15}, journal={CHEMICAL ENGINEERING SCIENCE}, author={Mao, D and Edwards, JR and Kuznetsov, AV and Srivastava, R}, year={2002}, month={Aug}, pages={3107–3117} }
@article{xiong_kuznetsov_2001, title={An investigation of the microporosity formation in an Al-4.1% Cu alloy casting in microgravity and in standard gravity}, volume={38}, ISSN={["0947-7411"]}, DOI={10.1007/s002310000186}, number={1-2}, journal={HEAT AND MASS TRANSFER}, author={Xiong, M and Kuznetsov, AV}, year={2001}, month={Nov}, pages={35–43} }
@article{xiong_kuznetsov_2001, title={Comparison between Lever and Scheil rules for modeling of microporosity formation during solidification}, volume={67}, ISSN={["1386-6184"]}, DOI={10.1023/A:1015291706970}, number={4}, journal={FLOW TURBULENCE AND COMBUSTION}, author={Xiong, M and Kuznetsov, AV}, year={2001}, pages={305–323} }
@article{kim_koo_kuznetsov_2001, title={Effect of anisotropy in permeability and effective thermal conductivity on thermal performance of an aluminum foam heat sink}, volume={40}, ISSN={["1040-7782"]}, DOI={10.1080/104077801300348851}, abstractNote={A numerical study has been carried out to investigate the thermal characteristics of an aluminum foam heat sink. An aluminum foam heat sink horizontally placed in a channel is modeled as a hydraulically and thermally anisotropic porous medium. A uniform heat flux is given from the bottom of the heat sink. Cold air is supplied from the top opening of the channel and exhausts to the channel outlet. Comprehensive numerical solutions are acquired to the governing Navier-Stokes and energy equations, using the Brinkman-Forchheimer extended Darcy model for the region of heat sink. It is assumed that the solid is in the local thermal equilibrium with the fluid. Details of flow and thermal fields are examined over wide ranges of the principal parameters: the Darcy number Da, the anisotropic permeability ratio K*(=K 2/K 1), and the anisotropic effective thermal conductivity ratio k*(=k 2/k 1). The results indicate that the anisotropy in permeability and effective thermal conductivity yields a significant change in ...}, number={1}, journal={NUMERICAL HEAT TRANSFER PART A-APPLICATIONS}, author={Kim, SY and Koo, JM and Kuznetsov, AV}, year={2001}, month={Jul}, pages={21–36} }
@article{nield_kuznetsov_2001, title={Effects of heterogeneity in forced convection in a porous medium: Parallel-plate channel, asymmetric property variation,and asymmetric heating}, volume={4}, DOI={10.1615/jpormedia.v4.i2.40}, abstractNote={The effects of variation (in the transverse direction) of permeability and thermal conductivity on fully developed forced convection in a parallel plate channel or circular duct filled with a saturated porous medium is investigated analytically on the basis of a Darcy model. Previous work on the case of symmetric property variation and symmetric heating is now supplemented by a study of the case of asymmetric property variation, for both symmetric and asymmetric heating, lsoflux and isotemperature boundary conditions are treated in turn. For the isofiux case, it is found that both permeability variation and conductivity variation lead to a reduction in the value of the Nusselt number Nu based on mean properties, but for the isotemperature case the situation is more complicated. For the isoflux case and permeability variation only, Nu is independent of the degree of asymmetric heating as represented by a flux ratio τ, but in the case of conductivity variation Nu is strongly dependent on τ and the degree of conductivity variation. In the case of isotemperature boundary conditions no fully developed solution exists when both the property variation and the heating are asymmetric.}, number={2}, journal={Journal of Porous Media}, author={Nield, D. A. and Kuznetsov, A. V.}, year={2001}, pages={137–148} }
@article{kuznetsov_nield_2001, title={Effects of heterogeneity in forced convection in a porous medium: Triple layer or conjugate problem}, volume={40}, ISSN={["1040-7782"]}, DOI={10.1080/104077801753238158}, abstractNote={The effects of variation (in the transverse direction) of permeability and thermal conductivity, on fully developed forced convection in a parallel plate channel or circular duct filled with a saturated porous medium, is investigated analytically on the basis of a Darcy model, for the cases of isoflux and isothermal boundaries. Previous work is extended to the case of a medium composed of three layers, or two layers with an adjacent solid layer. For the parallel plate channel with isoflux boundaries, some general multilayer results are given.}, number={4}, journal={NUMERICAL HEAT TRANSFER PART A-APPLICATIONS}, author={Kuznetsov, AV and Nield, DA}, year={2001}, month={Sep}, pages={363–385} }
@article{kuznetsov_2001, title={Influence of thermal dispersion on forced convection in a composite parallel-plate channel}, volume={52}, ISSN={["0044-2275"]}, DOI={10.1007/pl00001536}, number={1}, journal={ZEITSCHRIFT FUR ANGEWANDTE MATHEMATIK UND PHYSIK}, author={Kuznetsov, AV}, year={2001}, month={Jan}, pages={135–150} }
@article{kuznetsov_jiang_2001, title={Numerical investigation of bioconvection of gravitactic microorganisms in an isotropic porous medium}, volume={28}, ISSN={["0735-1933"]}, DOI={10.1016/S0735-1933(01)00291-3}, abstractNote={Abstract A new continuum model is formulated for bioconvection in a dilute suspension of swimming, gravitactic microorganisms in a porous medium. “Bioconvection” is the name given to pattern-forming convective motions set up in suspensions of swimming microorganisms. “Gravitaxis” means that microorganisms tend to swim against the gravity. The aim of this paper is to analyze collective behavior and pattern formation in populations of swimming microorganisms. The existence and stability of a two-dimensional plume in a tall, narrow chamber with stress-free sidewalls is investigated. Governing equations include Darcy law as well as microorganism conservation equation. A conservative finite-difference scheme is used to solve these equations numerically.}, number={7}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Kuznetsov, AV and Jiang, N}, year={2001}, month={Oct}, pages={877–886} }
@article{avramenko_kobzar_shevchuk_kuznetsov_iwanisov_2001, title={Symmetry of turbulent boundary-layer flows: Investigation of different eddy viscosity models}, volume={151}, ISSN={["0001-5970"]}, DOI={10.1007/BF01272521}, number={1-2}, journal={ACTA MECHANICA}, author={Avramenko, AA and Kobzar, SG and Shevchuk, IV and Kuznetsov, AV and Iwanisov, LT}, year={2001}, pages={1–14} }
@article{nield_kuznetsov_2001, title={The interaction of thermal nonequilibrium and heterogeneous conductivity effects in forced convection in layered porous channels}, volume={44}, ISSN={["0017-9310"]}, DOI={10.1016/S0017-9310(01)00078-3}, abstractNote={Forced convection in a parallel plate channel filled with a porous medium, consisting of two layers with the same porosity and permeability but with different solid conductivity, and saturated by a single fluid, is analyzed using a two-temperature model. It is found that the effect of local thermal nonequilibrium is particularly significant when the solid conductivity in each layer is greater than the fluid conductivity, and in these circumstances the effect is to reduce the Nusselt number defined in terms of the overall effective thermal conductivity.}, number={22}, journal={INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER}, author={Nield, DA and Kuznetsov, AV}, year={2001}, month={Nov}, pages={4369–4373} }
@article{nield_kuznetsov_2000, title={Effects of heterogeneity in forced convection in a porous medium: parallel plate channel or circular duct}, volume={43}, ISSN={["1879-2189"]}, DOI={10.1016/S0017-9310(00)00025-9}, abstractNote={The effects of variation (in the transverse direction) of permeability and thermal conductivity, on fully developed forced convection in a parallel plate channel or circular duct filled with a saturated porous medium, is investigated analytically on the basis of a Darcy or Dupuit–Forchheimer model. It is shown that the Dupuit–Forchheimer problem reduces to the Darcy problem with a changed permeability variation. The cases of isoflux and isothermal boundaries are treated in turn. The bulk of the results pertain to a two-step variation, but the case of a weak continuous variation is also considered. The results for the parallel plate geometry and for the circular duct geometry are qualitatively similar. The replacement of isoflux boundaries by isothermal boundaries leads to a reduction of Nusselt number but otherwise there is little change in the pattern. The results demonstrate that the effect of permeability variation is that an above average permeability near the walls leads to an increase in Nusselt number, and this is explained in terms of variation in the curvature of the temperature profile. The effect of conductivity variation is more complex; there are two opposing effects and the Nusselt number is not always a monotonic function of the conductivity variation.}, number={22}, journal={INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER}, author={Nield, DA and Kuznetsov, AV}, year={2000}, month={Nov}, pages={4119–4134} }
@article{kuznetsov_2000, title={Fluid flow and heat transfer analysis of Couette flow in a composite duct}, volume={140}, ISSN={["0001-5970"]}, DOI={10.1007/BF01182508}, number={3-4}, journal={ACTA MECHANICA}, author={Kuznetsov, AV}, year={2000}, pages={163–170} }
@article{xiong_kuznetsov_2000, title={Forced convection in a Couette flow in a composite duct: An analysis of thermal dispersion and non-Darcian effects}, volume={3}, DOI={10.1615/jpormedia.v3.i3.60}, abstractNote={In this article an analysis of fluid flow and heat transfer in a fully developed Couette flow through a composite channel that is partly filled with a clear fluid and partly with a fluid-saturated porous medium is presented. The porous medium is attached to a fixed plate and uniform heat fluxes of different intensities are imposed on both plates. The momentum transport is described by the Brinkman−Forchheimer−Darcy equation and the effect of transverse thermal dispersion is accounted for in the energy equation for the porous region. An analytical solution for the fluid flow is obtained utilizing the boundary layer technique. The temperature field and the Nusselt numbers at the upper and lower plates are obtained by direct numerical integration. The dependence of the Nusselt numbers on the thickness of the porous region, the ratio of heat fluxes on both plates, and the Darcy number is investigated.}, number={3}, journal={Journal of Porous Media}, author={Xiong, M. and Kuznetsov, A. V.}, year={2000}, pages={245–255} }
@article{kuznetsov_2000, title={Investigation of the effect of transverse thermal dispersion on forced convection in porous media}, volume={145}, ISSN={["1619-6937"]}, DOI={10.1007/BF01453643}, number={1-4}, journal={ACTA MECHANICA}, author={Kuznetsov, AV}, year={2000}, pages={35–43} }
@article{kuznetsov_xiong_2000, title={Numerical simulation of the effect of thermal dispersion on forced convection in a circular duct partly filled with a Brinkman-Forchheimer porous medium}, volume={10}, ISSN={["1758-6585"]}, DOI={10.1108/09615530010338169}, abstractNote={A numerical simulation of the fully developed forced convection in a circular duct partly filled with a fluid saturated porous medium is presented. The Brinkman‐Forchheimer‐extended Darcy equation is used to describe the fluid flow in the porous region. The energy equation for the porous region accounts for the effect of thermal dispersion. The dependence of the Nusselt number on a number of parameters, such as the Reynolds number, the Darcy number, the Forchheimer coefficient, as well as the thickness of the porous region is investigated. The numerical results obtained in this research are in agreement with published experimental data.}, number={5-6}, journal={INTERNATIONAL JOURNAL OF NUMERICAL METHODS FOR HEAT & FLUID FLOW}, author={Kuznetsov, AV and Xiong, M}, year={2000}, pages={488–501} }
@article{kim_kim_kuznetsov_2000, title={Simulation of coupled turbulent flow and heat transfer in the wedge-shaped pool of a twin-roll strip casting process}, volume={43}, ISSN={["0017-9310"]}, DOI={10.1016/S0017-9310(00)00013-2}, abstractNote={The proper choice of nozzle in a twin-roll strip casting process is important to obtain the stabilization of the molten steel and free surface and a stable temperature distribution in a wedge-shaped pool. In this study, a numerical investigation of the coupled turbulent flow and heat transfer in a twin-roll strip casting process was performed for two patterns of melt-feed through a nozzle. In addition, the patterns for the removal of superheat for different gap thicknesses were analyzed using a local Nusselt number along the roll surface. The flow turbulence was examined using the low-Reynolds-number k–ε turbulence model of Launder and Sharma. The results show that the use of a submerged nozzle may have a beneficial impact on the stabilization of the free-surface zone. The increased gap thickness yields an increased local Nusselt number in the downstream section of the wedge-shaped pool where the cross-sectional flow area is reduced.}, number={20}, journal={INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER}, author={Kim, WS and Kim, DS and Kuznetsov, AV}, year={2000}, month={Oct}, pages={3811–3822} }
@article{kuznetsov_1999, title={Analytical investigation of forced convection from a flat plate enhanced by a porous substrate}, volume={137}, ISSN={["0001-5970"]}, DOI={10.1007/bf01179210}, number={3-4}, journal={ACTA MECHANICA}, author={Kuznetsov, AV}, year={1999}, pages={211–223} }
@article{kuznetsov_1999, title={Fluid mechanics and heat transfer in the interface region between a porous medium and a fluid layer: A boundary layer solution}, volume={2}, DOI={10.1615/jpormedia.v2.i3.70}, number={3}, journal={Journal of Porous Media}, author={Kuznetsov, A. V.}, year={1999}, pages={309–321} }
@article{nield_kuznetsov_1999, title={Local thermal nonequilibrium effects in forced convection in a porous medium channel: a conjugate problem}, volume={42}, ISSN={["0017-9310"]}, DOI={10.1016/S0017-9310(98)00386-X}, abstractNote={Forced convection in a plane channel filled with a saturated porous medium, coupled with conduction in plane slabs bounding the channel, is investigated analytically on the basis of a two-temperature model allowing for local thermal nonequilibrium (LTNE). It is found that the effect of the finite thermal resistance due to the slabs is to reduce both the heat transfer to the porous medium and the degree of LTNE. An increase in value of the Péclet number leads to a decrease in the rate of exponential decay in the downstream direction but does not affect the value of a suitably defined Nusselt number. The dependence of the Nusselt number on a new solid–fluid heat exchange parameter, the solid/fluid thermal conductivity ratio, and the porosity, is investigated. The general two-temperature formulation of the thermal boundary conditions is discussed.}, number={17}, journal={INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER}, author={Nield, DA and Kuznetsov, AV}, year={1999}, month={Sep}, pages={3245–3252} }
@article{kuznetsov_1999, title={Parametric study of macrosegregation in the horizontal strip casting process for different cooling rates and different casting speeds}, volume={35}, ISSN={["0042-9929"]}, DOI={10.1007/s002310050314}, number={3}, journal={HEAT AND MASS TRANSFER}, author={Kuznetsov, AV}, year={1999}, month={Aug}, pages={197–203} }
@article{kuznetsov_1998, title={Analytical investigation of Couette flow in a composite channel partially filled with a porous medium and partially with a clear fluid}, volume={41}, ISSN={["0017-9310"]}, DOI={10.1016/S0017-9310(97)00296-2}, abstractNote={In this study, a new thermal lattice Boltzmann model (TLBM) is developed to simulate conjugate heat transfer in a microchannel heat sink (MCHS) with porous ribs and pulsatile flow inlet. The examined parameters include the rib to channel height ratio (Hr*), Strouhal number (St), and Reynolds number (Re), which are varied from 0.25 to 0.75, 0 to 3.2, and 100 to 300, respectively. The proposed TLBM is based on the double distribution function framework and capable of addressing heat transfer in combined fluid and porous media conditions. The simulation data show that the flow pulsation inside MCHS with porous ribs not only improves the bulk mean temperatures but also eliminates the rib recirculation zones at some phases, which promotes both the local and overall heat transfer. For fixed Re, the overall Nusselt number (Nu‾/Nu0) and Fanning friction coefficient (f‾/f0) increase and then decrease with increasing St. The maximum values appear at St = 2. For fixed Re and St, the thermal performance factor (TPF) displays a single peak trend with Hr* and the optimal TPF of 2.2 occurs at Hr*=0.5. In addition, compared with the previous ribbed, baffled, and porous MCHSs, the proposed porous rib design under pulsating conditions reports the highest Nu‾/Nu0 of 13.4 in the range of f‾/f0≤200. Finally, the correlations of Nu‾/Nu0 and f‾/f0 with Re, St, and Hr* for the present MCHS are established for the first time, with average differences below 6.7% and 12.4%, respectively.}, number={16}, journal={INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER}, author={Kuznetsov, AV}, year={1998}, month={Aug}, pages={2556–2560} }
@article{kuznetsov_1998, title={Analytical investigation of heat transfer in Couette flow through a porous medium utilizing the Brinkman-Forchheimer-extended Darcy model}, volume={129}, ISSN={["0001-5970"]}, DOI={10.1007/BF01379647}, number={1-2}, journal={ACTA MECHANICA}, author={Kuznetsov, AV}, year={1998}, pages={13–24} }
@article{kuznetsov_1998, title={Analytical study of fluid flow and heat transfer during forced convection in a composite channel partly filled with a Brinkman-Forchheimer porous medium}, volume={60}, ISSN={["1386-6184"]}, DOI={10.1023/A:1009998703180}, number={2}, journal={FLOW TURBULENCE AND COMBUSTION}, author={Kuznetsov, AV}, year={1998}, pages={173–192} }
@article{kuznetsov_nield, title={Forced convection with slip-flow in a channel occupied by a hyperporous medium saturated by a rarefied gas (vol 64, pg 161, 2006)}, volume={85}, number={2}, journal={Transport in Porous Media}, author={Kuznetsov, A. V. and Nield, D. A.}, pages={657–658} }
@article{kuznetsov_nield, title={Thermally developing forced convection in a porous medium occupied by a rarefied gas: Parallel plate channel or circular tube with walls at constant heat flux (vol 76, pg 345, 2009)}, volume={85}, number={2}, journal={Transport in Porous Media}, author={Kuznetsov, A. V. and Nield, D. A.}, pages={657–658} }