@article{dsouza_vashaee_2023, title={Cooperative Pseudo Jahn Teller distortion derives phase transitions in bismuth oxide}, volume={299}, ISSN={["1879-3312"]}, DOI={10.1016/j.matchemphys.2023.127534}, abstractNote={Bismuth oxide exhibits a complex array of structures with a broad range of properties of various technological importance. We derive the phase transition pathway using the in-situ heating X-ray diffraction data, evidencing four polymorphs of α, β, δ, and γ. We prove that the observed phase transitions are due to the cooperative pseudo-Jahn-Teller distortion in the crystal originating from mixing the ground state Bi6s and excited Bi6p states. Using the electron localization function and crystal orbital theory, we explore the role of the Bi3+ lone pair in the second-order phase transition. It is found that the O2p states have a critical role in stabilizing the lone pair activity, which leads to a pseudo-Jahn Teller distortion cooperatively inducing the phase transition.}, journal={MATERIALS CHEMISTRY AND PHYSICS}, author={Dsouza, Kelvin and Vashaee, Daryoosh}, year={2023}, month={Apr} }
@article{yalameha_nourbakhsh_vashaee_2023, title={ELATooLs: A tool for analyzing anisotropic elastic properties of the 2D and 3D materials (vol 271, 108195, 2022)}, volume={288}, ISSN={["1879-2944"]}, DOI={10.1016/j.cpc.2023.108728}, journal={COMPUTER PHYSICS COMMUNICATIONS}, author={Yalameha, Shahram and Nourbakhsh, Zahra and Vashaee, Daryoosh}, year={2023}, month={Jul} }
@article{nourizadeh_vaez_vashaee_2023, title={Emerging Weyl Semimetal States in Ternary TaPxAs1-x Alloys: Insights from Electronic and Topological Analysis}, ISSN={["2511-9044"]}, DOI={10.1002/qute.202300072}, abstractNote={This study presents a thorough analysis of the electronic structures of the TaPxAs1−x series of compounds, which are of significant interest due to their potential as topological materials. Using a combination of first principles and Wannier-based tight-binding methods, this study investigates both the bulk and surface electronic structures of the compounds for varying compositions (x = 0, 0.25, 0.50, 0.75, 1), with a focus on their topological properties. By using chirality analysis, (111) surface electronic structure analysis, and surface Fermi arcs analysis, it is established that the TaPxAs1−x compounds exhibit topologically nontrivial behavior, characterized as Weyl semimetals (WSMs). The effect of spin–orbit coupling (SOC) on the topological properties of the compounds is further studied. In the absence of SOC, the compounds exhibit linearly dispersive fourfold degenerate points in the first Brillouin zone (FBZ) resembling Dirac semimetals. However, the introduction of SOC induces a phase transition to WSM states, with the number and position of Weyl points (WPs) varying depending on the composition of the alloy. For example, TaP has 12 WPs in the FBZ. The findings provide novel insights into the electronic properties of TaPxAs1−x compounds and their potential implications for the development of topological materials for various technological applications.}, journal={ADVANCED QUANTUM TECHNOLOGIES}, author={Nourizadeh, Samira Sadat and Vaez, Aminollah and Vashaee, Daryoosh}, year={2023}, month={May} }
@article{rafiefard_fardindoost_kisomi_shooshtari_irajizad_seddighi_mohammadpour_vashaee_2023, title={High-performance flexible and stretchable self-powered surface engineered PDMS-TiO2 nanocomposite based humidity sensors driven by triboelectric nanogenerator with full sensing range}, volume={378}, ISSN={["0925-4005"]}, DOI={10.1016/j.snb.2022.133105}, abstractNote={Harvesting electrical charge using triboelectrification provides a promising path to realizing uninterrupted self-powered sensors with application in wearable electronics and personal healthcare. This paper reports a high-performance flexible and stretchable self-powered humidity sensor based on triboelectric nanogenerators (TENG) that provides extreme responsivity, excellent repeatability with fast recovery time, and high selectivity. The device relies on a surface-engineered titanium oxide nanoparticle-silicone nanocomposite that generates triboelectric charge density strongly dependent on ambient humidity. The performance of the nanoengineered humidity sensor was systematically investigated at different humidity levels, which exhibits high responsivity (90% change for 75% RH change), a fast response time (1 s for 50% RH), a fast recovery time (3 s for 50% RH), and nearly full sensing range (0–99%). When activated by vertical contact separation at 2 Hz, the device generates a power density as high as 90 mW.m−2 and an open-circuit voltage of 50 V. An analytical model is derived to understand the underlying mechanism. The theoretical data explain the role of dielectric permittivity and surface area on the device operation, and the results are in good agreement with the experiments. The excellent combination of the properties suggests that these flexible TENGs can serve as reliable self-powered motion-driven humidity sensor.}, journal={SENSORS AND ACTUATORS B-CHEMICAL}, author={Rafiefard, Nassim and Fardindoost, Somayeh and Kisomi, Masoumeh Karimi and Shooshtari, Leyla and Irajizad, Azam and Seddighi, Sadegh and Mohammadpour, Raheleh and Vashaee, Daryoosh}, year={2023}, month={Mar} }
@article{yalameha_nourbakhsh_bahramy_vashaee_2023, title={New insights into band inversion and topological phase of TiNI monolayer}, ISSN={["1463-9084"]}, DOI={10.1039/d3cp00005b}, abstractNote={Two-dimensional (2D) topological insulators (TIs) hold great promise for future quantum information technologies. Among the 2D-TIs, the TiNI monolayer has recently been proposed as an ideal material for achieving the quantum spin Hall effect at room temperature. Theoretical predictions suggest a sizable bandgap due to the spin-orbit coupling (SOC) of the electrons at and near the Fermi level with a nontrivial 2 topology of the electronic states, which is robust under external strain. However, our detailed first-principles calculations reveal that, in contrast to these predictions, the TiNI monolayer has a trivial bandgap in the equilibrium state with no band inversion, despite SOC opening the bandgap. Moreover, we show that electron correlation effects significantly impact the topological and structural stabilities of the system under external strains. We employed a range of density functional theory (DFT) approaches, including HSE06, PBE0, TB-mBJ, and GGA+U, to comprehensively investigate the nontrivial topological properties of this monolayer. Our results demonstrate that using general-purpose functionals such as PBE-GGA for studying TIs can lead to false predictions, potentially misleading experimentalists in their efforts to discover new TIs.}, journal={PHYSICAL CHEMISTRY CHEMICAL PHYSICS}, author={Yalameha, Shahram and Nourbakhsh, Zahra and Bahramy, Mohammad Saeed and Vashaee, Daryoosh}, year={2023}, month={Apr} }
@article{yamini_santos_fortulan_gazder_malhotra_vashaee_serhiienko_mori_2023, title={Room-Temperature Thermoelectric Performance of n-Type Multiphase Pseudobinary Bi2Te3-Bi2S3 Compounds: Synergic Effects of Phonon Scattering and Energy Filtering}, ISSN={["1944-8252"]}, DOI={10.1021/acsami.3c01956}, abstractNote={Bismuth telluride-based alloys possess the highest efficiencies for the low-temperature-range (<500 K) applications among thermoelectric materials. Despite significant advances in the efficiency of p-type Bi2Te3-based materials through engineering the electronic band structure by convergence of multiple bands, the n-type pair still suffers from poor efficiency due to a lower number of electron pockets near the conduction band edge than the valence band. To overcome the persistent low efficiency of n-type Bi2Te3-based materials, we have fabricated multiphase pseudobinary Bi2Te3–Bi2S3 compounds to take advantages of phonon scattering and energy filtering at interfaces, enhancing the efficiency of these materials. The energy barrier generated at the interface of the secondary phase of Bi14Te13S8 in the Bi2Te3 matrix resulted in a higher Seebeck coefficient and consequently a higher power factor in multiphase compounds than the single-phase alloys. This effect was combined with low thermal conductivity achieved through phonon scattering at the interfaces of finely structured multiphase compounds and resulted in a relatively high thermoelectric figure of merit of ∼0.7 over the 300–550 K temperature range for the multiphase sample of n-type Bi2Te2.75S0.25, double the efficiency of single-phase Bi2Te3. Our results inform an alternative alloy design to enhance the performance of thermoelectric materials.}, journal={ACS APPLIED MATERIALS & INTERFACES}, author={Yamini, Sima Aminorroaya and Santos, Rafael and Fortulan, Raphael and Gazder, Azdiar A. and Malhotra, Abhishek and Vashaee, Daryoosh and Serhiienko, Illia and Mori, Takao}, year={2023}, month={Apr} }
@article{yamini_santos_fortulan_gazder_malhotra_vashaee_serhiienko_mori_2023, title={Room-Temperature Thermoelectric Performance of n-Type Multiphase Pseudobinary Bi2Te3-Bi2S3 Compounds: Synergic Effects of Phonon Scattering and Energy Filtering}, ISSN={["1944-8252"]}, DOI={10.1021/acsami.3c0195619220}, journal={ACS APPLIED MATERIALS & INTERFACES}, author={Yamini, Sima Aminorroaya and Santos, Rafael and Fortulan, Raphael and Gazder, Azdiar A. and Malhotra, Abhishek and Vashaee, Daryoosh and Serhiienko, Illia and Mori, Takao}, year={2023}, month={Apr} }
@article{alidoosti_esfahani_yalameha_vashaee_2023, title={Unlocking the potential of hexagonal boron sheets: Giant improvements in thermal conductivity and mechanics through molybdenum intercalation}, volume={32}, ISSN={["2542-5293"]}, DOI={10.1016/j.mtphys.2023.101012}, abstractNote={A new two-dimensional (2D) material, MoB4, known as a Dirac material, has been found to possess exceptional electronic properties and promising thermal and mechanical characteristics. Our calculations reveal that MoB4 has a remarkable Young's modulus of 384 N/m, surpassing that of graphene. Additionally, we predict that MoB4 exhibits a thermal conductivity of 461 W/mK at room temperature. This is a significant improvement when compared to a single boron sheet in a honeycomb structure and MoB2, showing 32 and 8 times higher thermal conductivity, respectively. This enhancement in thermal conductivity is attributed to the suppression of anharmonicity and scattering phase space, along with an increased group velocity in MoB4.}, journal={MATERIALS TODAY PHYSICS}, author={Alidoosti, Mohammad and Esfahani, Davoud Nasr and Yalameha, Shahram and Vashaee, Daryoosh}, year={2023}, month={Mar} }
@article{fazeli_etesami_nourbakhsh_vashaee_2023, title={Unveiling the properties of transition-metal dichalcogenides: a comprehensive study of WTe2, WSe2, ZrTe2, and NiTe2 in bulk and monolayer forms}, ISSN={["1573-4803"]}, DOI={10.1007/s10853-023-08545-w}, journal={JOURNAL OF MATERIALS SCIENCE}, author={Fazeli, Yasaman and Etesami, Zeynab and Nourbakhsh, Zahra and Vashaee, Daryoosh}, year={2023}, month={Jun} }
@article{fazeli_etesami_nourbakhsh_vashaee_2023, title={Unveiling the properties of transition-metal dichalcogenides: a comprehensive study of WTe2, WSe2, ZrTe2, and NiTe2 in bulk and monolayer forms (vol 58, pg 10023, 2023)}, volume={58}, ISSN={["1573-4803"]}, DOI={10.1007/s10853-023-08656-4}, number={24}, journal={JOURNAL OF MATERIALS SCIENCE}, author={Fazeli, Yasaman and Etesami, Zeynab and Nourbakhsh, Zahra and Vashaee, Daryoosh}, year={2023}, month={Jun}, pages={10217–10217} }
@article{ghorbani_eshraghi_dodaran_kameli_protasowicki_johnson_vashaee_2022, title={Effect of Yb doping on the structural and magnetic properties of cobalt ferrite nanoparticles
}, volume={147}, ISSN={["1873-4227"]}, DOI={10.1016/j.materresbull.2021.111642}, abstractNote={The low coercivity of spinel ferrites is a significant barrier limiting their use in high-density magnetic recording applications. The large magnitude of the magnetocrystalline anisotropy of the rare earth group elements can lead to a high coercivity field by doping the magnetic ferrites with these elements. In this research, using the hydrothermal method, Fe+3 in cobalt ferrite was substituted with Yb+3 to make CoFe2-xYbxO4 with x = 0, 0.025, 0.05, 0.075, and 0.1. By analyzing the X-ray diffraction analysis and confirming the spinel structure, the crystallite sizes were obtained in the range of 31 nm to 45 nm. The lattice parameter was estimated to be in the range of 8.30 nm to 8.36 nm. The FTIR analysis of the nanoparticles showed the ν1 absorption band in the range 584 Cm−1 to 594 Cm−1. The Raman spectroscopy analysis showed that CoFe2-xYbxO4 nanoparticles have a mixed spinel structure. Hysteresis loops at room temperature and 10 K obtained by the vibrating sample magnetometer (VSM) indicate that the coercivity field (HC) increases significantly from 0.55 to 1.05 KOe and 9.48 to 12.00 KOe, respectively, by increasing Yb doping from x = 0 to x = 0.1.}, journal={MATERIALS RESEARCH BULLETIN}, author={Ghorbani, H. and Eshraghi, M. and Dodaran, A. A. Sabouri and Kameli, P. and Protasowicki, Stacey and Johnson, Camron' and Vashaee, Daryoosh}, year={2022}, month={Mar} }
@article{ghazinezhad_kameli_varzaneh_sarsari_norouzi-inallu_amiri_salazar_rodriguez-crespo_vashaee_etsell_et al._2022, title={Cd-doping effects in Ni-Mn-Sn: experiment and ab-initio study}, volume={55}, ISSN={["1361-6463"]}, DOI={10.1088/1361-6463/ac5f33}, abstractNote={Abstract Martensitic transformation (MT), magnetic properties, and magnetocaloric effect (MCE) in Heusler-type Ni47Mn40Sn13-xCdx (x = 0, 0.75, 1, 1.25 at. %) metamagnetic shape memory alloys (MetaMSMAs) are investigated, both experimentally and theoretically, as a function of doping with Cd. Ab-initio computations reveal that the ferromagnetic (FM) configuration is energetically more favorable in the cubic phase than the antiferromagnetic (AFM) state in undoped and doped alloys as well. Moreover, it is revealed that the alloys in the ground state exhibit a tetragonal structure confirming the existence of MT, in agreement with the experiments. It was indicated, both in theory and practice, that a reduction of the unit cell volume and an increase of the MT temperature as a function of the Cd doping. Indirect estimations of MCE in the vicinity of MT were carried out by using thermomagnetization curves measured under different magnetic fields up to 5 T. The results demonstrated that the doped alloys exhibit enhanced values of the inverse MCE comparable with those of Ni-Mn-based MetaMSMAs. Maximum magnetic entropy change in a field change of 2 T increases from 3.0 for the undoped alloy to 3.4 and 5.0 for the alloys doped with 0.75 and 1 at.% of Cd, respectively. The inverse and conventional MCE were explored by direct measurements of the adiabatic temperature change under the magnetic field change of 1.96 T. The Cd doping increased the maximum of inverse MCE by nearly 78% from 0.9 K to 1.6 K for the undoped and doped alloys, respectively. The results depicted that Cd doping can effectively tailor the structural, magnetic, and MCE properties of the Ni–Mn–Sn MetaMSMAs.}, number={25}, journal={JOURNAL OF PHYSICS D-APPLIED PHYSICS}, author={Ghazinezhad, Z. and Kameli, P. and Varzaneh, A. Ghotbi and Sarsari, I. Abdolhosseini and Norouzi-Inallu, M. and Amiri, T. and Salazar, D. and Rodriguez-Crespo, B. and Vashaee, D. and Etsell, T. H. and et al.}, year={2022}, month={Jun} }
@article{baraeinejad_shayan_vazifeh_rashidi_hamedani_tavolinejad_gorji_razmara_vaziri_vashaee_et al._2022, title={Design and Implementation of an Ultralow-Power ECG Patch and Smart Cloud-Based Platform}, volume={71}, ISSN={["1557-9662"]}, DOI={10.1109/TIM.2022.3164151}, abstractNote={This article reports the development of a new smart electrocardiogram (ECG) monitoring system, consisting of the related hardware, firmware, and Internet of Things (IoT)-based web service for artificial intelligence (AI)-assisted arrhythmia detection and a complementary Android application for data streaming. The hardware aspect of this article proposes an ultralow power patch sampling ECG data at 256 samples/s with 16-bit resolution. The battery life of the device is two weeks per charging, which alongside the flexible and slim (193.7 mm $\times62.4$ mm $\times8.6$ mm) and lightweight (43 g) allows the user to continue real-life activities while the real-time monitoring is being done without interruption. The power management is achieved through the usage of switching converters, ultralow power component choice, as well as intermittent usage of them through firmware optimization. A novel data encoding method is also proposed to allow the compression of data and lower the runtime. The software aspect, in addition to the web ECG analysis platform and the Android streaming and monitoring application, provides an arrhythmia detection service. The key innovations in this regard are the usage of a set of new factors in determining arrhythmia that grants higher accuracy while retaining the detection near-real-time. The arrhythmia detection algorithm shows 98.7% accuracy using artificial neural network and K-nearest neighbors methods and 98.1% using decision tree method on test dataset.}, journal={IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT}, author={Baraeinejad, Bardia and Shayan, Masood Fallah and Vazifeh, Amir Reza and Rashidi, Diba and Hamedani, Mohammad Saberi and Tavolinejad, Hamed and Gorji, Pouya and Razmara, Parsa and Vaziri, Kiarash and Vashaee, Daryoosh and et al.}, year={2022} }
@article{bhatnagar_vashaee_2022, title={Development of MEMS Process Compatible (Bi,Sb)(2)(Se,Te)(3)-Based Thin Films for Scalable Fabrication of Planar Micro-Thermoelectric Generators}, volume={13}, ISSN={["2072-666X"]}, DOI={10.3390/mi13091459}, abstractNote={Bismuth telluride-based thin films have been investigated as the active material in flexible and micro thermoelectric generators (TEGs) for near room-temperature energy harvesting applications. The latter is a class of compact printed circuit board compatible devices conceptualized for operation at low-temperature gradients to generate power for wireless sensor nodes (WSNs), the fundamental units of the Internet-of-Things (IoT). CMOS and MEMS compatible micro-TEGs require thin films that can be integrated into the fabrication flow without compromising their thermoelectric properties. We present results on the thermoelectric properties of (Bi,Sb)2(Se,Te)3 thin films deposited via thermal evaporation of ternary compound pellets on four-inch SiO2 substrates at room temperature. Thin-film compositions and post-deposition annealing parameters are optimized to achieve power factors of 2.75 mW m-1 K-2 and 0.59 mW m-1 K-2 for p-type and n-type thin films. The measurement setup is optimized to characterize the thin-film properties accurately. Thin-film adhesion is further tested and optimized on several substrates. Successful lift-off of p-type and n-type thin films is completed on the same wafer to create thermocouple patterns as per the target device design proving compatibility with the standard MEMS fabrication process.}, number={9}, journal={MICROMACHINES}, author={Bhatnagar, Prithu and Vashaee, Daryoosh}, year={2022}, month={Sep} }
@article{yalameha_nourbakhsh_vashaee_2022, title={ELATooLs: A tool for analyzing anisotropic elastic properties of the 2D and 3D materials}, volume={271}, ISSN={["1879-2944"]}, DOI={10.1016/j.cpc.2021.108195}, abstractNote={We introduce a computational method and a user-friendly code with a terminal-based graphical user interface (GUI), named ElATools, developed to analyze mechanical and anisotropic elastic properties. ElATools enables facile analysis of the second-order elastic stiffness tensor of two-dimensional (2D) and three-dimensional (3D) crystal systems. It computes and displays the main mechanical properties including the bulk modulus, Young's modulus, shear modulus, hardness, p-wave modulus, universal anisotropy index, Chung-Buessem anisotropy index, log-Euclidean anisotropy parameter, Cauchy pressures, Poisson's ratio, and Pugh's ratio, using three averaging schemes of Voigt, Reuss, and Hill. It includes an online and offline database from the Materials Project with more than 13,000 elastic stiffness constants for 3D materials. The program supports output files of the well-known computational codes IRelast, IRelast2D, ElaStic, and AELAS. Four types of plotting and visualization tools are integrated to conveniently interface with GNUPLOT, XMGRACE, view3dscene and plotly libraries, offering immediate post-processing of the results. ElATools provides reliable means to investigate the mechanical stability based on the calculation of six (three) eigenvalues of the elastic tensor in 3D (2D) materials. It can efficiently identify anomalous mechanical properties, such as negative linear compressibility, negative Poisson's ratio, and highly-anisotropic elastic modulus in 2D and 3D materials, which are central properties to design and develop high-performance nanoscale electromechanical devices. Moreover, ElATools can predict the behavior of the sound velocities and their anisotropic properties, such as acoustic phase/group velocities and power flow angles in materials, by solving the Christoffel equation. Six case studies on selected material systems, namely, ZnAu2(CN)4, CrB2, δ-phosphorene, Pd2O6Se2 monolayer, and GaAs, and a hypothetical set of systems with cubic symmetry are presented to demonstrate the descriptive and predictive capabilities of ElATools. Program Title: ElATools CPC Library link to program files: https://doi.org/10.17632/njh92x66c6.1 Developer's repository link: https://github.com/shahramyalameha/ElATools Licensing provisions: GNU General Public Licence 3.0 Programming language: Fortran 90 External routines/libraries: LaPack, Blas, and Plotly Javascript libraries, GNUPLOT, XMGRACE, view3dscene. Nature of problem: Identifying anisotropic elastic properties of 2D and 3D materials, and calculating acoustic phase and group velocities in homogeneous solids. Solution method: Second-order elastic stiffness tensor analysis using transformation law and calculations of the elastic surfaces properties. Solving the Christoffel equation eigenvalue problem using diagonalization and calculations of the sound velocities. Additional comments: Documentation available at https://yalameha.gitlab.io/elastictools/index.html}, journal={COMPUTER PHYSICS COMMUNICATIONS}, author={Yalameha, Shahram and Nourbakhsh, Zahra and Vashaee, Daryoosh}, year={2022}, month={Feb} }
@article{dsouza_vashaee_2022, title={EMReact: a tool for modelling electromagnetic field induced effects in chemical reactions by solving the discrete stochastic master equation}, ISSN={["1362-3028"]}, DOI={10.1080/00268976.2022.2152744}, abstractNote={The effects of electromagnetic fields (EMF) have been widely debated concerning their role in chemical reactions. Reactions usually took hours or days to complete, and have been shown to happen a thousand times faster using EMF radiations. This work develops a formalism and a computer program to evaluate and quantify the EMF effects in chemical reactions. The master equation employed in this program solves the internal energy of the reaction under EMFs while including collisional effects. Multiphoton absorption and emission are made possible with the transitioning energy close to the EMF and are influenced by the dielectric properties of the system. Dimethyl Sulfoxide and Benzyl Chloride are simulated under different EMF intensities. The results show that EMF absorption is closely related to the collisional redistribution of energy in molecules. The EMF effect can be interpreted as a shift of the thermodynamic equilibrium. Under such nonequilibrium energy distribution, the "temperature" is not a reliable quantity for defining the state of the system.}, journal={MOLECULAR PHYSICS}, author={Dsouza, Kelvin and Vashaee, Daryoosh}, year={2022}, month={Dec} }
@article{moseley_taddei_yan_mcguire_calder_polash_vashaee_zhang_zhao_parker_et al._2022, title={Giant doping response of magnetic anisotropy in MnTe}, volume={6}, ISSN={["2475-9953"]}, url={https://doi.org/10.1103/PhysRevMaterials.6.014404}, DOI={10.1103/PhysRevMaterials.6.014404}, abstractNote={The authors show that minuscule amounts of Li suffice to tune antiferromagnetic MnTe from an easy-plane to easy-axis material. Upon heating towards the N\'eel temperature of 307 K, the spins do not gradually rotate back to a planar orientation, and instead maintain their axial orientation up to a relatively high temperature of 260 K, before quickly switching back to a planar orientation and crossing into the paramagnetic phase. Calculations indicate MnTe bears two competing magnetic ground states which can be manipulated by slightly shifting the Fermi level via Li-doping. Easy manipulation of the spins in MnTe could have significant implications for future spintronic devices and materials.}, number={1}, journal={PHYSICAL REVIEW MATERIALS}, author={Moseley, Duncan H. and Taddei, Keith M. and Yan, Jiaqiang and McGuire, Michael A. and Calder, Stuart and Polash, M. M. H. and Vashaee, Daryoosh and Zhang, Xiaofan and Zhao, Huaizhou and Parker, David S. and et al.}, year={2022}, month={Jan} }
@article{bhatnagar_vashaee_2022, title={Process Considerations for selective doping of poly-Si thin films with spin-on dopants and nickel silicide formation for planar thermoelectric devices}, volume={150}, ISSN={["1873-4081"]}, DOI={10.1016/j.mssp.2022.106941}, abstractNote={The formation of highly doped p-type (boron-doped) and n-type (phosphorus-doped) poly-Si thin films with spin-on dopants on the same wafer poses unique challenges. This work evaluates the pros and cons of different approaches to dopant diffusion, residue removal, and diffusion mask selection when working with spin-on dopants. The experiments have been carried out to optimize the formation of highly doped poly-Si thin films that will form the active layers of a micro-thermoelectric generator (μ-TEG). Building upon previous work on residue removal methods, we report that the residue formation is also dependent on the oxide-silicon surface with a PECVD oxide-Si interface not requiring a post-dopant diffusion nitric acid treatment to achieve a hydrophobic surface. Furthermore, comparing the direct dispense and proximity diffusion methods verifies the existing reports of enhanced diffusion in the latter case. Besides, we observe that doping first with Boron is more conducive than doping first with phosphorus to reduce sheet resistance. We also optimize the contact formation with Ti/Ni thin films and report the mean contact resistivity. Notably, contact annealing precludes the nitric acid treatment requirement even if the surface is hydrophilic after removing dopant residue. Additionally, the sequence of silicidation is observed to be dependent on the doping of the underlying areas.}, journal={MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING}, author={Bhatnagar, Prithu and Vashaee, Daryoosh}, year={2022}, month={Nov} }
@article{yalameha_nourbakhsh_vashaee_2022, title={Topological phase and thermoelectric properties of bialkali bismuthide compounds (Na, K)(2)RbBi from first-principles}, volume={34}, ISSN={["1361-648X"]}, DOI={10.1088/1361-648X/ac431d}, abstractNote={We report the topological phase and thermoelectric properties of bialkali bismuthide compounds (Na, K)2RbBi, as yet hypothetical. The topological phase transitions of these compounds under hydrostatic pressure are investigated. The calculated topological surface states andZ2topological index confirm the nontrivial topological phase. The electronic properties and transport coefficients are obtained using the density functional theory combined with the Boltzmann transport equation. The relaxation times are determined using the deformation potential theory to calculate the electronic thermal and electrical conductivity. The calculated mode Grüneisen parameters are substantial, indicating strong anharmonic acoustic phonons scattering, which results in an exceptionally low lattice thermal conductivity. These compounds also have a favorable power factor leading to a relatively flat p-type figure-of-merit over a broad temperature range. Furthermore, the mechanical properties and phonon band dispersions show that these structures are mechanically and dynamically stable. Therefore, they offer excellent candidates for practical applications over a wide range of temperatures.}, number={10}, journal={JOURNAL OF PHYSICS-CONDENSED MATTER}, author={Yalameha, Shahram and Nourbakhsh, Zahra and Vashaee, Daryoosh}, year={2022}, month={Mar} }
@article{tangestani_hadianfard_tayebi_vashaee_2022, title={Wear and Electrochemical Behavior of High-Nitrogen, Nickel-Free Austenitic Stainless Steel Produced by Hot Powder Forging}, ISSN={["1544-1024"]}, DOI={10.1007/s11665-022-06779-4}, journal={JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE}, author={Tangestani, A. and Hadianfard, M. J. and Tayebi, L. and Vashaee, D.}, year={2022}, month={Mar} }
@article{polash_vashaee_2021, title={Anomalous Thermoelectric Transport Properties of Fe-Rich Magnetic FeTe}, volume={15}, ISSN={["1862-6270"]}, url={https://doi.org/10.1002/pssr.202100231}, DOI={10.1002/pssr.202100231}, abstractNote={The interplay between magnetism and quantum effects has motivated several thermoelectric studies on iron-telluride yet with little insight on the anomalous features in transport properties near magnetostructural transition temperature (≈70 K). A detailed investigation is carried out on Fe1.1Te by characterizing magnetic, heat capacity, galvanomagnetic, and thermoelectric transport properties to understand the electronic, magnetic, and structural origin of those anomalies. The magnetic susceptibility indicates a bicollinear stripe and short-range ordering in the antiferromagnetic and paramagnetic domains, respectively. Hall conductivity and transverse magnetoresistance reveal a multicarrier transport impacted by spin fluctuations and magnons. Contributions from phonon-drag and magnon-drag are evaluated to understand the origin of the broad peak in antiferromagnetic thermopower. The peak at ≈50 K and the insignificant entropy contribution from the magnonic heat capacity support the phonon-drag as the origin. The field-dependent enhancement of thermal conductivity must be associated with field-dependent spin-phonon coupling modification. The field-induced thermopower reduction can be attributed to the suppression of magnons or paramagnons, as evidenced by the magnetic susceptibility data. Above 70 K, the thermal conductivity drops sharply due to the structural change modifying phonon modes. Understanding these properties originated from the spin, and quantum effects are instrumental for designing high-performance spin-driven thermoelectrics.}, number={10}, journal={PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS}, publisher={Wiley}, author={Polash, Md Mobarak Hossain and Vashaee, Daryoosh}, year={2021}, month={Aug} }
@article{zaferani_ghomashchi_vashaee_2021, title={Assessment of Thermoelectric, Mechanical, and Microstructural Reinforcement Properties of Graphene-Mixed Heterostructures}, volume={4}, ISSN={["2574-0962"]}, DOI={10.1021/acsaem.1c00015}, abstractNote={We examine the role of graphene nanoplates (GNPs) in the critical properties of thermoelectric GNP nanocomposites. After a detailed analysis of the thermoelectric, microstructural, and mechanical c...}, number={4}, journal={ACS APPLIED ENERGY MATERIALS}, author={Zaferani, Sadeq Hooshmand and Ghomashchi, Reza and Vashaee, Daryoosh}, year={2021}, month={Apr}, pages={3573–3583} }
@article{nozariasbmarz_dycus_cabral_flack_krasinski_lebeau_vashaee_2021, title={Efficient self-powered wearable electronic systems enabled by microwave processed thermoelectric materials}, volume={283}, ISSN={["1872-9118"]}, DOI={10.1016/j.apenergy.2020.116211}, abstractNote={The integrated body sensor networks are expected to dominate the future of healthcare, making a critical paradigm shift that will support people in the comfort and security of their own homes. Thermoelectric generators, in this regard, can play a crucial role as they can steadily generate electricity from body heat and enable self-powered wearable or implantable medical, health, and sports devices. This work provides a comprehensive analysis of the operation and the optimization of wearable thermoelectric generators under different human body conditions. Thermoelectric design principles, wearable system considerations, and a novel method to synthesize the materials specially designed for body heat harvesting are presented. The limitations of the materials and systems for wearable applications are deliberated in detail, and the feasibility of eliminating the heatsink for enhancing body comfort is examined. N-type Bi2Te3-xSex was synthesized using a novel approach based on field-induced decrystallization by microwave radiation to achieve the optimum properties. This method resulted in amorphous-crystalline nanocomposites with simultaneously large thermopower and small thermal conductivity around the body temperature. Thermoelectric generators were fabricated from the optimized materials and packaged in flexible elastomers. The devices generated up to 150% higher voltage and 600% more power on the body compared to the commercial ones and, so far, are the best in class for body heat harvesting in wearable applications.}, journal={APPLIED ENERGY}, author={Nozariasbmarz, Amin and Dycus, J. Houston and Cabral, Matthew J. and Flack, Chloe M. and Krasinski, Jerzy S. and LeBeau, James M. and Vashaee, Daryoosh}, year={2021}, month={Feb} }
@article{heidari_hadianfard_khalifeh_vashaee_tayebi_2021, title={Fabrication of nanocrystalline austenitic stainless steel with superior strength and ductility via binder assisted extrusion method}, volume={379}, ISSN={["1873-328X"]}, DOI={10.1016/j.powtec.2020.10.028}, abstractNote={Biomedical austenitic stainless steel (ASTM F2581) has been processed by the powder metallurgy technology using binder assisted extrusion method and aside a sintering aid. The resultant microstructure was examined by optical microscopy, field emission scanning electron microscopy, transmission electron microscopy and x-ray diffraction methods. The optical microscopy images indicate that using the binder and sintering aid considerably decreases the porosities of the sintered samples. The x-ray diffraction and transmission electron microscopy images reveal that the microstructure of the sintered alloy consists of austenite in nanocrystalline form and amorphous phases. The mechanical properties were measured through compressive tests. The mean yield strength is estimated at about 824 MPa, and the compressive strength exceeds 1GPa, which is superior to the austenitic stainless steel produced through the conventional methods. Furthermore, the process followed here is compatible with large scale industrial production at a reasonable cost.}, journal={POWDER TECHNOLOGY}, author={Heidari, L. and Hadianfard, M. J. and Khalifeh, A. R. and Vashaee, D. and Tayebi, L.}, year={2021}, month={Feb}, pages={38–48} }
@article{padmanabhan ramesh_sargolzaeiaval_neumann_misra_vashaee_dickey_ozturk_2021, title={Flexible thermoelectric generator with liquid metal interconnects and low thermal conductivity silicone filler}, volume={5}, ISSN={["2397-4621"]}, DOI={10.1038/s41528-021-00101-3}, abstractNote={Abstract Harvesting body heat using thermoelectricity provides a promising path to realizing self-powered, wearable electronics that can achieve continuous, long-term, uninterrupted health monitoring. This paper reports a flexible thermoelectric generator (TEG) that provides efficient conversion of body heat to electrical energy. The device relies on a low thermal conductivity aerogel–silicone composite that secures and thermally isolates the individual semiconductor elements that are connected in series using stretchable eutectic gallium-indium (EGaIn) liquid metal interconnects. The composite consists of aerogel particulates mixed into polydimethylsiloxane (PDMS) providing as much as 50% reduction in the thermal conductivity of the silicone elastomer. Worn on the wrist, the flexible TEGs present output power density figures approaching 35 μWcm − 2 at an air velocity of 1.2 ms − 1 , equivalent to walking speed. The results suggest that these flexible TEGs can serve as the main energy source for low-power wearable electronics.}, number={1}, journal={NPJ FLEXIBLE ELECTRONICS}, author={Padmanabhan Ramesh, Viswanath and Sargolzaeiaval, Yasaman and Neumann, Taylor and Misra, Veena and Vashaee, Daryoosh and Dickey, Michael D. and Ozturk, Mehmet C.}, year={2021}, month={Mar} }
@article{yalameha_nourbakhsh_ramazani_vashaee_2021, title={Highly stable full Heusler order Cs(Na, K)(2)Bi with diverse topological phases controlled by strain engineering}, volume={273}, ISSN={["1873-4944"]}, DOI={10.1016/j.mseb.2021.115430}, abstractNote={We predict the highly stable new full-Heusler order compound Cs(Na, K)2Bi, that can take a diverse set of topological states by strain-engineering. Based on first-principles studies, our findings reveal that the hydrostatic lattice compression, uniaxial compression, and uniaxial tension can transition Cs(Na, K)2Bi to a trivial semiconductor, a normal insulator, a topological insulator, a Weyl semimetal, a Dirac semimetal, and a Nodal Line semimetal. These topological states, induced by various kinds of strain, exhibit a range of interesting optical and electronic transport properties. These results introduce Cs(Na, K)2Bi compounds as promising candidates to make novel topological devices whose properties can be controlled using strain-engineering.}, journal={MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS}, author={Yalameha, Shahram and Nourbakhsh, Zahra and Ramazani, Ali and Vashaee, Daryoosh}, year={2021}, month={Nov} }
@article{polash_vashaee_2021, title={Infinite-stage Nernst-Ettingshausen Cryocooler for Practical Applications}, volume={15}, ISSN={["2331-7019"]}, url={https://doi.org/10.1103/PhysRevApplied.15.014011}, DOI={10.1103/PhysRevApplied.15.014011}, abstractNote={Recent developments in Nernst-Ettingshausen (NE) physical phenomena combined with advances in the performance of rare-earth permanent magnets make thermomagnetic (TM) cryocoolers well suited for practical applications. The device performance of a NE cryocooler depends on both the material and the geometric shape of the device. Despite continued progress in TM materials, the optimum shape is still based on a simplified infinite-stage model derived in 1963 by Harman [Adv. Energy Convers. 3(4), 667--676 (1963)]. Harman's model assumes several nonrealistic assumptions, such as temperature-independent material properties and constant current density. We relax such assumptions and derive a fully-temperature-dependent numerical model to accurately solve for the thermomagnetic features of a NE cooler with arbitrary geometry. We correct Harman's analytical function and compare its performance with the performance of devices of various shapes. The corrected shape has a higher coefficient of performance (COP) at higher temperature differentials, which indicates that when the material resistivity is a strong function of the temperature, the corrected infinite-stage device can provide better performance than Harman's geometry. Moreover, the corrected infinite-shape device can provide higher heat flow density under a similar optimum-COP condition. A case study based on a state-of-the-art TM material, $\mathrm{Bi}$-$\mathrm{Sb}$ alloy, is presented, and the critical parameters for designing an efficient thermomagnetic cooler are discussed in detail.}, number={1}, journal={PHYSICAL REVIEW APPLIED}, author={Polash, M. Mobarak Hossain and Vashaee, Daryoosh}, year={2021}, month={Jan} }
@article{polash_mohaddes_rasoulianboroujeni_vashaee_2021, title={Magnon-drag thermopower in antiferromagnets versus ferromagnets (vol 8, pg 4049, 2020)}, volume={9}, ISSN={["2050-7534"]}, DOI={10.1039/d1tc90030g}, abstractNote={Correction for ‘Magnon-drag thermopower in antiferromagnets versus ferromagnets’ by Md. Mobarak Hossain Polash et al., J. Mater. Chem. C, 2020, 8, 4049–4057, DOI: 10.1039/C9TC06330G.}, number={8}, journal={JOURNAL OF MATERIALS CHEMISTRY C}, author={Polash, Md. Mobarak Hossain and Mohaddes, Farzad and Rasoulianboroujeni, Morteza and Vashaee, Daryoosh}, year={2021}, month={Feb}, pages={2978–2978} }
@article{yalameha_nourbakhsh_ramazani_vashaee_2021, title={Promising Bialkali Bismuthides Cs(Na, K)(2)Bi for High-Performance Nanoscale Electromechanical Devices: Prediction of Mechanical and Anisotropic Elastic Properties under Hydrostatic Tension and Compression and Tunable Auxetic Properties}, volume={11}, ISSN={["2079-4991"]}, DOI={10.3390/nano11102739}, abstractNote={Using first-principles calculations, we predict highly stable cubic bialkali bismuthides Cs(Na, K)2Bi with several technologically important mechanical and anisotropic elastic properties. We investigate the mechanical and anisotropic elastic properties under hydrostatic tension and compression. At zero pressure, CsK2Bi is characterized by elastic anisotropy with maximum and minimum stiffness along the directions of [111] and [100], respectively. Unlike CsK2Bi, CsNa2Bi exhibits almost isotropic elastic behavior at zero pressure. We found that hydrostatic tension and compression change the isotropic and anisotropic mechanical responses of these compounds. Moreover, the auxetic nature of the CsK2Bi compound is tunable under pressure. This compound transforms into a material with a positive Poisson's ratio under hydrostatic compression, while it holds a large negative Poisson's ratio of about -0.45 along the [111] direction under hydrostatic tension. An auxetic nature is not observed in CsNa2Bi, and Poisson's ratio shows completely isotropic behavior under hydrostatic compression. A directional elastic wave velocity analysis shows that hydrostatic pressure effectively changes the propagation pattern of the elastic waves of both compounds and switches the directions of propagation. Cohesive energy, phonon dispersion, and Born-Huang conditions show that these compounds are thermodynamically, mechanically, and dynamically stable, confirming the practical feasibility of their synthesis. The identified mechanisms for controlling the auxetic and anisotropic elastic behavior of these compounds offer a vital feature for designing and developing high-performance nanoscale electromechanical devices.}, number={10}, journal={NANOMATERIALS}, author={Yalameha, Shahram and Nourbakhsh, Zahra and Ramazani, Ali and Vashaee, Daryoosh}, year={2021}, month={Oct} }
@article{polash_vashaee_2021, title={Spin fluctuations yield zT enhancement in ferromagnets}, volume={24}, ISSN={["2589-0042"]}, url={https://doi.org/10.1016/j.isci.2021.103356}, DOI={10.1016/j.isci.2021.103356}, abstractNote={Thermal fluctuation of local magnetization intercoupled with charge carriers and phonons offers a path to enhance thermoelectric performance. Thermopower enhancement by spin fluctuations (SF) has been observed before. However, the crucial evidence for enhancing thermoelectric-figure-of-merit (zT) by SF has not been reported until now. Here we report that the SF leads to nearly 80% zT enhancement in ferromagnetic CrTe near and below TC ∼ 335 K. The ferromagnetism is originated from the collective electronic and localized magnetic moments. The field-dependent transport properties demonstrate the profound impact of SF on the electrons and phonons. Under an external magnetic field, the enhancement in thermopower is suppressed, and the thermal conductivity is enhanced, evidencing the existence of a strong SF. The anomalous thermoelectric transport properties are analyzed based on theoretical models, and a good agreement with experimental data is found. This study contributes to the fundamental understanding of SF for designing high-performance spin-driven thermoelectrics.}, number={11}, journal={ISCIENCE}, publisher={Elsevier BV}, author={Polash, Md Mobarak Hossain and Vashaee, Daryoosh}, year={2021}, month={Nov} }
@misc{zaferani_jafarian_vashaee_ghomashchi_2021, title={Thermal Management Systems and Waste Heat Recycling by Thermoelectric Generators-An Overview}, volume={14}, ISSN={["1996-1073"]}, DOI={10.3390/en14185646}, abstractNote={With the fast evolution in greenhouse gas (GHG) emissions (e.g., CO2, N2O) caused by fossil fuel combustion and global warming, climate change has been identified as a critical threat to the sustainable development of human society, public health, and the environment. To reduce GHG emissions, besides minimizing waste heat production at the source, an integrated approach should be adopted for waste heat management, namely, waste heat collection and recycling. One solution to enable waste heat capture and conversion into useful energy forms (e.g., electricity) is employing solid-state energy converters, such as thermoelectric generators (TEGs). The simplicity of thermoelectric generators enables them to be applied in various industries, specifically those that generate heat as the primary waste product at a temperature of several hundred degrees. Nevertheless, thermoelectric generators can be used over a broad range of temperatures for various applications; for example, at low temperatures for human body heat harvesting, at mid-temperature for automobile exhaust recovery systems, and at high temperatures for cement industries, concentrated solar heat exchangers, or NASA exploration rovers. We present the trends in the development of thermoelectric devices used for thermal management and waste heat recovery. In addition, a brief account is presented on the scientific development of TE materials with the various approaches implemented to improve the conversion efficiency of thermoelectric compounds through manipulation of Figure of Merit, a unitless factor indicative of TE conversion efficiency. Finally, as a case study, work on waste heat recovery from rotary cement kiln reactors is evaluated and discussed.}, number={18}, journal={ENERGIES}, author={Zaferani, Sadeq Hooshmand and Jafarian, Mehdi and Vashaee, Daryoosh and Ghomashchi, Reza}, year={2021}, month={Sep} }
@article{hooshmand zaferani_ghomashchi_vashaee_2021, title={Thermoelectric, Magnetic, and Mechanical Characteristics of Antiferromagnetic Manganese Telluride Reinforced with Graphene Nanoplates}, volume={23}, ISSN={["1527-2648"]}, DOI={10.1002/adem.202000816}, abstractNote={Mechanical and thermal stability are the two challenging aspects of thermoelectric compounds and modules. Microcrack formation during material synthesis and mechanical failure under thermo‐mechanical loading is commonly observed in thermoelectric materials made from brittle semiconductors. Herein, the results of graphene‐nanoplates (GNPs) reinforcement on the mechanical and thermoelectric properties of MnTe compound are reported. The binary antiferromagnetic MnTe shown promising thermoelectric characteristics due to the paramagnon–hole drag above the Néel temperature. In this study, different bulk MnTe samples are synthesized with the addition of GNPs in a small quantity (0.25–1 wt%) by powder metallurgy and spark plasma sintering. The thermoelectric factors, magnetic behavior, microstructure, and mechanical properties of the samples are evaluated and analyzed. Nearly 33% improvement is observed in the fracture toughness of MnTe reinforced with 0.25 wt% GNPs compared to the pristine structure. The Néel temperature remains approximately unaffected with the GNP inclusion; however, the low‐temperature ferromagnetic phase impurity is significantly suppressed. The thermal conductivity and power factor decrease almost equally by ≈34% at 600 K; hence, the thermoelectric figure‐of‐merit is not affected by GNP reinforcement in the optimized sample.}, number={2}, journal={ADVANCED ENGINEERING MATERIALS}, author={Hooshmand Zaferani, Sadeq and Ghomashchi, Reza and Vashaee, Daryoosh}, year={2021}, month={Feb} }
@misc{polash_yalameha_zhou_ahadi_nourbakhsh_vashaee_2021, title={Topological quantum matter to topological phase conversion: Fundamentals, materials, physical systems for phase conversions, and device applications}, volume={145}, ISSN={["1879-212X"]}, url={https://doi.org/10.1016/j.mser.2021.100620}, DOI={10.1016/j.mser.2021.100620}, abstractNote={The spin-orbit coupling field, an atomic magnetic field inside a Kramers’ system, or discrete symmetries can create a topological torus in the Brillouin Zone and provide protected edge or surface states, which can contain relativistic fermions, namely, Dirac and Weyl Fermions. The topology-protected helical edge or surface states and the bulk electronic energy band define different quantum or topological phases of matters, offering an excellent prospect for some unique device applications. Device applications of the quantum materials rely primarily on understanding the topological properties, their mutual conversion processes under different external stimuli, and the physical system for achieving the phase conversion. There have been tremendous efforts in finding new topological materials with exotic topological phases. However, the application of the topological properties in devices is still limited due to the slow progress in developing the physical structures for controlling the topological phase conversions. Such control systems often require extreme tuning conditions or the fabrication of complex multi-layered topological structures. This review article highlights the details of the topological phases, their conversion processes, along with their potential physical systems, and the prospective application fields. A general overview of the critical factors for topological phases and the materials properties are further discussed to provide the necessary background for the following sections.}, journal={MATERIALS SCIENCE & ENGINEERING R-REPORTS}, publisher={Elsevier BV}, author={Polash, Md Mobarak Hossain and Yalameha, Shahram and Zhou, Haihan and Ahadi, Kaveh and Nourbakhsh, Zahra and Vashaee, Daryoosh}, year={2021}, month={Jul} }
@article{polash_moseley_zhang_hermann_vashaee_2021, title={Understanding and design of spin-driven thermoelectrics}, volume={2}, ISSN={["2666-3864"]}, url={https://doi.org/10.1016/j.xcrp.2021.100614}, DOI={10.1016/j.xcrp.2021.100614}, abstractNote={While progress in thermoelectric materials based on the engineering of electronic and phononic characteristics is reaching a plateau, the addition of the spin degree of freedom has the potential to open a new landscape for alternative thermoelectric materials. Here, we present the concepts, current understanding, and guidelines for designing spin-driven thermoelectrics. We show that the interplay between the spin and heat currents in entropy transport via charge carriers can offer a path to enhance the electronic thermopower. The classical antiferromagnetic semiconductor manganese telluride (MnTe) is chosen as the case study due to its significant spin-mediated thermoelectric properties. We show that, although the spin-disorder scattering reduces the carrier mobility in magnetic materials, spin entropy, magnon, and paramagnon carrier drags can dominate and significantly enhance the thermoelectric power factor, and hence zT. Finally, several guidelines are drawn based on the current understanding for designing high-performance spin-driven thermoelectric materials.}, number={11}, journal={CELL REPORTS PHYSICAL SCIENCE}, publisher={Elsevier BV}, author={Polash, Md Mobarak Hossain and Moseley, Duncan and Zhang, Junjie and Hermann, Raphael P. and Vashaee, Daryoosh}, year={2021}, month={Nov} }
@article{heidari_tabatabaei_razavi_lari_tavangar_romanos_vashaee_tayebi_2020, title={3D construct of hydroxyapatite/zinc oxide/palladium nanocomposite scaffold for bone tissue engineering}, volume={31}, ISSN={["1573-4838"]}, DOI={10.1007/s10856-020-06409-2}, number={10}, journal={JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE}, author={Heidari, Fatemeh and Tabatabaei, Fahimeh Sadat and Razavi, Mehdi and Lari, Reza Bazargan and Tavangar, Mina and Romanos, Georgios E. and Vashaee, Daryoosh and Tayebi, Lobat}, year={2020}, month={Sep} }
@article{tahriri_torres_karkazis_karkazis_bader_vashaee_tayebi_2020, title={Applications of Hard and Soft Tissue Engineering in Dentistry}, ISBN={["978-3-030-21582-8"]}, DOI={10.1007/978-3-030-21583-5_8}, journal={APPLICATIONS OF BIOMEDICAL ENGINEERING IN DENTISTRY}, author={Tahriri, Mohammadreza and Torres, Regine and Karkazis, Emelia and Karkazis, Alexander and Bader, Rizwan and Vashaee, Daryoosh and Tayebi, Lobat}, year={2020}, pages={179–193} }
@article{nozariasbmarz_vashaee_2020, title={Effect of Microwave Processing and Glass Inclusions on Thermoelectric Properties of P-Type Bismuth Antimony Telluride Alloys for Wearable Applications}, volume={13}, ISSN={["1996-1073"]}, DOI={10.3390/en13174524}, abstractNote={Depending on the application of bismuth telluride thermoelectric materials in cooling, waste heat recovery, or wearable electronics, their material properties, and geometrical dimensions should be designed to optimize their performance. Recently, thermoelectric materials have gained a lot of interest in wearable electronic devices for body heat harvesting and cooling purposes. For efficient wearable electronic devices, thermoelectric materials with optimum properties, i.e., low thermal conductivity, high Seebeck coefficient, and high thermoelectric figure-of-merit (zT) at room temperature, are demanded. In this paper, we investigate the effect of glass inclusion, microwave processing, and annealing on the synthesis of high-performance p-type (BixSb1−x)2Te3 nanocomposites, optimized specially for body heat harvesting and body cooling applications. Our results show that glass inclusion could enhance the room temperature Seebeck coefficient by more than 10% while maintaining zT the same. Moreover, the combination of microwave radiation and post-annealing enables a 25% enhancement of zT at room temperature. A thermoelectric generator wristband, made of the developed materials, generates 300 μW power and 323 mV voltage when connected to the human body. Consequently, MW processing provides a new and effective way of synthesizing p-type (BixSb1−x)2Te3 alloys with optimum transport properties.}, number={17}, journal={ENERGIES}, author={Nozariasbmarz, Amin and Vashaee, Daryoosh}, year={2020}, month={Sep} }
@article{heidari_tangestani_hadianfard_vashaee_tayebi_2020, title={Effect of fabrication method on the structure and properties of a nanostructured nickel-free stainless steel}, volume={31}, ISSN={["1568-5527"]}, DOI={10.1016/j.apt.2020.06.025}, abstractNote={An ASTM F2581 nanostructured stainless steel was fabricated by two different powder metallurgy routes; Hot Powder Forging (HPF) and Binder Assisted Extrusion (BAE) methods. Their structure and mechanical properties were investigated and compared. In both fabrication methods, the alloy powder was made by using main alloying elements through mechanical alloying, along with the addition of a sintering aid. In the BAE method, a paste was prepared by mixing alloy powders with polymer followed by cold extrusion, polymer removal, and sintering. In the HPF method, the alloy powders were hot forged under high pressure. The structure and the size of the austenite crystallite of the samples were investigated by scanning electron microscopy (SEM), FE-SEM, x-ray diffraction (XRD) and transmission electron microscopy (TEM). It was determined that the samples prepared by the HPF method are generally denser than those made via BAE. The porosities are smaller and almost uniform in size and morphology in the HPF method. Furthermore, microhardness and tensile tests were performed on the samples. The results show that the ductility of BAE samples is higher than the HPF samples. The fracture surface of the BAE sample has deeper dimples, indicating higher ductility for BAE samples. On the other hand, both the hardness and strength of HPF samples are higher than those of the BAE samples. The results show that both methods produced specimens with considerably higher strength and hardness than conventional 316L stainless steel.}, number={8}, journal={ADVANCED POWDER TECHNOLOGY}, author={Heidari, L. and Tangestani, A. and Hadianfard, M. J. and Vashaee, D. and Tayebi, L.}, year={2020}, month={Aug}, pages={3408–3419} }
@article{malhotra_hosseini_zaferani_hall_vashaee_2020, title={Enhancement of Diffusion, Densification and Solid-State Reactions in Dielectric Materials Due to Interfacial Interaction of Microwave Radiation: Theory and Experiment}, volume={12}, ISSN={["1944-8252"]}, DOI={10.1021/acsami.0c09719}, abstractNote={A detailed theoretical model and experimental study are presented that formulate and prove the existence of a robust ponderomotive force (PMF) near the interfaces in a granular dielectric material under microwave radiation. The model calculations show that the net direction of the PMF is pore angle-dependent. For most of the pore angles, the net force is towards the interface creating a mass transport that fills the interfacial pores and facilitates densification. For small ranges of angles, near 180o and 360o, PMF drives the ions in the reverse direction and depletes the pores. However, the net force for such ranges of angles is small. The PMF also enhances the diffusion of the mobile ionic species and, consequently, accelerates the solid-state reaction by increasing the collision probability. The proof-of-concept experiments show that a mixture of elemental powders can diffuse, react, and form dense materials when radiated by the microwave in just a few minutes. Such characteristics, together with field-induced decrystallization, offer a novel and simple approach for the synthesis of nanostructured compounds, which can have practical implications in ceramic technologies and thermoelectric materials.}, number={45}, journal={ACS APPLIED MATERIALS & INTERFACES}, author={Malhotra, Abhishek and Hosseini, Mahshid and Zaferani, Sadeq Hooshmand and Hall, Michael and Vashaee, Daryoosh}, year={2020}, month={Nov}, pages={50941–50952} }
@article{azizi_heidari_fahimipour_sajjadnejad_vashaee_tayebi_2020, title={Evaluation of mechanical and biocompatibility properties of hydroxyapatite/manganese dioxide nanocomposite scaffolds for bone tissue engineering application}, volume={17}, ISSN={["1744-7402"]}, DOI={10.1111/ijac.13549}, abstractNote={Abstract The aim of this research was to evaluate the mechanical properties, biocompatibility, and degradation behavior of scaffolds made of pure hydroxyapatite (HA) and HA‐modified by MnO 2 for bone tissue engineering applications. HA and MnO 2 were developed using sol‐gel and precipitation methods, respectively. The scaffolds properties were characterized using X‐ray diffraction (XRD), Fourier transform spectroscopy (FTIR), scanning electron microcopy (SEM), energy dispersive spectroscopy (EDS), and transmission electron microscopy (TEM). The interaction of scaffold with cells was assessed using in vitro cell proliferation and alkaline phosphatase (ALP) assays. The obtained results indicate that the HA/MnO 2 scaffolds possess higher compressive strength, toughness, hardness, and density when compared to the pure HA scaffolds. After immersing the scaffold in the SBF solution, more deposited apatite appeared on the HA/MnO 2 , which results in the rougher surface on this scaffold compared to the pure HA scaffold. Finally, the in vitro biological analysis using human osteoblast cells reveals that scaffolds are biocompatible with adequate ALP activity.}, number={5}, journal={INTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY}, author={Azizi, Fatemeh and Heidari, Fatemeh and Fahimipour, Farahnaz and Sajjadnejad, Mohammad and Vashaee, Daryoosh and Tayebi, Lobat}, year={2020}, month={Sep}, pages={2439–2449} }
@article{zaferani_darebaghi_hong_vashaee_ghomashchi_2020, title={Experimental Realization of Heavily p-doped Half-Heusler CoVSn Compound}, volume={13}, ISSN={["1996-1073"]}, DOI={10.3390/en13061459}, abstractNote={Hypothetical half-Heusler (HH) ternary alloy of CoVSn has already been computationally investigated for possible spintronics and thermoelectric applications. We report the experimental realization of this compound and the characterizations of its thermoelectric properties. The material was synthesized by a solid-state reaction of the stoichiometric amounts of the elements via powder metallurgy (30 h mechanical milling and annealing at 900 °C for 20 h) and spark plasma sintering (SPS). The temperature-dependent ternary thermodynamic phase diagram of Co-V-Sn was further calculated. The phase diagram and detailed analysis of the synthesized material revealed the formation of the non-stoichiometry HH CoVSn, mixed with the binary intermetallic phases of SnV3, Co2Sn, and Co3V. The combination of X-ray diffraction, energy-dispersive X-ray spectroscopy, and thermoelectric transport properties confirmed the formation of a multi-phase compound. The analysis revealed the predicted thermoelectric features (zT = 0.53) of the highly doped CoVSn to be compromised by the formation of intermetallic phases (zT ≈ 0.007) during synthesis. The additional phases changed the properties from p- to overall n-type thermoelectric characteristics.}, number={6}, journal={ENERGIES}, author={Zaferani, Sadeq Hooshmand and Darebaghi, Alireza and Hong, Soon-Jik and Vashaee, Daryoosh and Ghomashchi, Reza}, year={2020}, month={Mar} }
@article{sargolzaeiaval_ramesh_neumann_misra_vashaee_dickey_ozturk_2020, title={Flexible thermoelectric generators for body heat harvesting - Enhanced device performance using high thermal conductivity elastomer encapsulation on liquid metal interconnects}, volume={262}, ISSN={["1872-9118"]}, DOI={10.1016/j.apenergy.2019.114370}, abstractNote={Abstract This paper reports flexible thermoelectric generators (TEGs) employing eutectic gallium indium (EGaIn) liquid metal interconnects encased in a novel, high thermal conductivity (HTC) elastomer. These TEGs are part of a broader effort to harvest thermal energy from the body and convert it into electrical energy to power wearable electronics. The flexible TEGs reported in this paper employ the same thermoelectric legs' used in rigid TEGs, thus eliminating the need to develop new materials specifically for flexible TEGs that often sacrifice the so-called figure of merit' for flexibility. Flexible TEGs reported here embed rigid thermoelectric legs' in soft and flexible packaging, using stretchable EGaIn interconnects. The use of liquid metal interconnects provides ultimate stretchability and low electrical resistance between the thermoelectric legs. The liquid metal lines are encased in a new stretchable silicone elastomer doped with both graphene nano-platelets and EGaIn to increase its thermal conductivity. This high thermal conductivity elastomer not only reduces the parasitic thermal resistance of the encapsulation layer but it also serves as a heat spreader, leading to 1.7X improvement in the output power density of TEGs compared to devices fabricated with a conventional elastomer. The device performance is further improved by a thin Cu layer acting as a heat spreader providing an additional 1.3X enhancement in the output power at 1.2 m/s air velocity (typical walking speed). Worn on the wrist, our best devices achieve power levels in excess of 30 μW/cm2 at an air velocity of 1.2 m/s outperforming previously reported flexible TEGs.}, journal={APPLIED ENERGY}, author={Sargolzaeiaval, Yasaman and Ramesh, Viswanath Padmanabhan and Neumann, Taylor V and Misra, Veena and Vashaee, Daryoosh and Dickey, Michael D. and Ozturk, Mehmet C.}, year={2020}, month={Mar} }
@article{tavangar_heidari_hayati_tabatabaei_vashaee_tayebi_2020, title={Manufacturing and characterization of mechanical, biological and dielectric properties of hydroxyapatite-barium titanate nanocomposite scaffolds}, volume={46}, ISSN={["1873-3956"]}, DOI={10.1016/j.ceramint.2019.12.157}, abstractNote={In this research, hydroxyapatite (HA)-based ceramics were produced as suitable ceramic implants for orthopedic applications. To improve the physical, mechanical, electrical and biological properties of pure HA, we developed composite scaffolds of HA-barium titanate (BT) by cold isostatic pressing and sintering. Microstructure, crystal phases, and molecular structure were analyzed by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR), respectively. Bulk density values were measured using the Archimedes method. The effect of different percentages of BT on cell proliferation, viability, and ALP activity of dental pulp stem cells (DPSCs) was assessed by ProstoBlue assay, Live/Dead staining, and p-NPP assay. The obtained results indicate that the HA-BT scaffolds possess higher compressive strength, toughness, density, and hardness compared with pure HA scaffolds. After immersing the scaffold in SBF solution, more deposited apatite appeared on the HA-BT, which results in rougher surface on this scaffold thanpure HA. Electrical properties of HA in the presence of BT are improved. Based on the results of cell culture experiments, composites containing 40, 50 and 60 %wt of BT have excellent biocompatibility, with the best results occurring for the sample with 50 %wt BT.}, number={7}, journal={CERAMICS INTERNATIONAL}, author={Tavangar, Mina and Heidari, Fatemeh and Hayati, Raziye and Tabatabaei, Fahimeh and Vashaee, Daryoosh and Tayebi, Lobat}, year={2020}, month={May}, pages={9086–9095} }
@article{heidari_bazargan-lari_razavi_fahimipour_vashaee_tayebi_2020, title={Nano-hydroxyapatite and nano-hydroxyapatite/zinc oxide scaffold for bone tissue engineering application}, volume={17}, ISSN={["1744-7402"]}, DOI={10.1111/ijac.13596}, number={6}, journal={INTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY}, author={Heidari, Fatemeh and Bazargan-Lari, Reza and Razavi, Mehdi and Fahimipour, Farahnaz and Vashaee, Daryoosh and Tayebi, Lobat}, year={2020}, month={Nov}, pages={2752–2761} }
@article{talebi_ghahfarokhi_vashaee_2020, title={Photoinduced tunable birefringence and dichroism in silver nanogratings}, volume={37}, ISSN={["1520-8540"]}, DOI={10.1364/JOSAB.399604}, abstractNote={Silver nanogratings are anisotropic plasmonic nanostructures with potential application in optical components due to their large birefringence and dichroism. We induced linear birefringence and linear dichroism in subwavelength Ag-AgCl films by irradiating with a single low-power linearly polarized laser beam. The laser beam aligns silver nanoparticles in the direction of laser polarization and forms nanograting. We used Stokes parameters to determine linear birefringence and linear dichroism in silver aligned nanostructures. The values of linear dichroism and linear birefringence in silver nanogratings are controllable through manipulating the spatial period of nanogratings. The dispersion characteristic of dichroism and birefringence is also investigated.}, number={10}, journal={JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS}, author={Talebi, Razieh and Ghahfarokhi, Forough Taheri and Vashaee, Daryoosh}, year={2020}, month={Oct}, pages={2848–2855} }
@misc{nozariasbmarz_collins_dsouza_polash_hosseini_hyland_liu_malhotra_ortiz_mohaddes_et al._2020, title={Review of wearable thermoelectric energy harvesting: From body temperature to electronic systems}, volume={258}, ISSN={["1872-9118"]}, url={https://publons.com/publon/30967440/}, DOI={10.1016/j.apenergy.2019.114069}, abstractNote={Abstract Global demand for battery-free metrics and health monitoring devices has urged leading research agencies and their subordinate centers to set human energy harvesting and self-powered wearable technologies as one of their primary research objectives. After an overview of wearables market trends, different active and passive methods of body energy harvesting for powering low-consumption electronic devices are introduced, and challenges of device fabrication are discussed. The discussion continues with the primary emphasis on thermoelectric generators for body heat harvesting. The physiological aspects of the human body involved in heat generation are elaborated. System requirements and the influence of different parameters on the performance of thermoelectric generators are studied at the material, device, and system levels. Finally, the advancements in the development of rigid and flexible thermoelectric generators for wearable and textile integration are presented.}, journal={APPLIED ENERGY}, author={Nozariasbmarz, Amin and Collins, Henry and Dsouza, Kelvin and Polash, Mobarak Hossain and Hosseini, Mahshid and Hyland, Melissa and Liu, Jie and Malhotra, Abhishek and Ortiz, Francisco Matos and Mohaddes, Farzad and et al.}, year={2020}, month={Jan} }
@article{nozariasbmarz_suarez_dycus_cabral_lebeau_ozturk_vashaee_2020, title={Thermoelectric generators for wearable body heat harvesting: Material and device concurrent optimization}, volume={67}, ISSN={["2211-3282"]}, DOI={10.1016/j.nanoen.2019.104265}, abstractNote={Abstract Body heat harvesting systems based on thermoelectric generators (TEGs) can play a significant role in wearable electronics intended for continuous, long-term health monitoring. However, to date, the harvested power density from the body using TEGs is limited to a few micro-watts per square centimeter, which is not sufficient to turn on many wearables. The thermoelectric materials research has been mainly focused on enhancing the single parameter zT, which is insufficient to meet the requirements for wearable applications. To develop TEGs that work effectively in wearable devices, one has to consider the material, device, and system requirements concurrently. Due to the lack of an efficient heatsink and the skin thermal resistance, a key challenge to achieving this goal is to design systems that maximize the temperature differential across the TEG while not compromising the body comfort. This requires favoring approaches that deliver the largest possible device thermal resistance relative to the external parasitic resistances. Therefore, materials with low thermal conductivity are critically important to maximize the temperature gradient. Also, to achieve a high boost converter efficiency, wearable TEGs need to have the highest possible output voltage, which calls for a high Seebeck coefficient. At the device level, dimensions of the legs (length versus the base area) and fill factor are both critical parameters to ensure that the parasitic thermal resistances are again negligible compared to the resistance of the module itself. In this study, the concurrent impact of material and device parameters on the efficiency of wearable TEGs is considered. Nanocomposite thermoelectric materials based on bismuth telluride alloys were synthesized using microwave processing and optimized to meet the requirements of wearable TEGs. Microwave energy decrystallized the material leading to a strong reduction of the thermal conductivity while maintaining a high zT at the body temperature. A comprehensive quasi-3D analytical model was developed and used to optimize the material and device parameters. The nanocomposite TEG produced 44 μW/cm2 under no air flow condition, and 156.5 μW/cm2 under airflow. In comparison to commercial TEGs tested under similar conditions, the nanocomposite based TEGs exhibited 4–7 times higher power density on the human body depending on the convective cooling conditions.}, journal={NANO ENERGY}, author={Nozariasbmarz, Amin and Suarez, Francisco and Dycus, J. Houston and Cabral, Matthew J. and LeBeau, James M. and Ozturk, Mehmet C. and Vashaee, Daryoosh}, year={2020}, month={Jan} }
@article{fahimipour_dashtimoghadam_hasani-sadrabadi_vargas_vashaee_lobner_kashi_ghasemzadeh_tayebi_2019, title={Enhancing cell seeding and osteogenesis of MSCs on 3D printed scaffolds through injectable BMP2 immobilized ECM-Mimetic gel}, volume={35}, ISSN={["1879-0097"]}, DOI={10.1016/j.dental.2019.04.004}, abstractNote={Design of bioactive scaffolds with osteogenic capacity is a central challenge in cell-based patient-specific bone tissue engineering. Efficient and spatially uniform seeding of (stem) cells onto such constructs is vital to attain functional tissues. Herein we developed heparin functionalized collagen gels supported by 3D printed bioceramic scaffolds, as bone extracellular matrix (ECM)-mimetic matrices. These matrices were designed to enhance cell seeding efficiency of mesenchymal stem cells (MSCs) as well as improve their osteogenic differentiation through immobilized bone morphogenic protein 2 (BMP2) to be used for personalized bone regeneration. A 3D gel based on heparin-conjugated collagen matrix capable of immobilizing recombinant human bone morphogenic protein 2 (BMP2) was synthesized. Isolated dental pulp Mesenchymal stem cells (MSCs) were then encapsulated into the bone ECM microenvironment to efficiently and uniformly seed a bioactive ceramic-based scaffold fabricated using additive manufacturing technique. The designed 3D cell-laden constructs were comprehensively investigated trough in vitro assays and in vivo study. In-depth rheological characterizations of heparin-conjugated collagen gel revealed that elasticity of the matrix is significantly improved compared with freely incorporated heparin. Investigation of the MSCs laden collagen-heparin hydrogels revealed their capability to provide spatiotemporal bioavailability of BMP2 while suppressing the matrix contraction over time. The in vivo histology and real-time polymerase chain reaction (qPCR) analysis showed that the designed construct supported the osteogenic differentiation of MSCs and induced the ectopic bone formation in rat model. The presented hybrid constructs combine bone ECM chemical cues with mechanical function providing an ideal 3D microenvironment for patient-specific bone tissue engineering and cell therapy applications. The implemented methodology in design of ECM-mimetic 3D matrix capable of immobilizing BMP2 to improve seeding efficiency of customized scaffolds can be exploited for other bioactive molecules.}, number={7}, journal={DENTAL MATERIALS}, author={Fahimipour, Farahnaz and Dashtimoghadam, Erfan and Hasani-Sadrabadi, Mohammad Mandi and Vargas, Jessica and Vashaee, Daryoosh and Lobner, Douglas C. and Kashi, Tahereh S. Jafarzadeh and Ghasemzadeh, Behnam and Tayebi, Lobat}, year={2019}, month={Jul}, pages={990–1006} }
@article{nozariasbmarz_hosseini_vashaee_2019, title={Interfacial ponderomotive force in solids leads to field induced dissolution of materials and formation of non-equilibrium nanocomposites}, volume={179}, ISSN={["1873-2453"]}, DOI={10.1016/j.actamat.2019.08.017}, abstractNote={We report that microwave radiation can decompose continuous solid-solution materials into their constituent phases – a process that is thermodynamically unfavorable at equilibrium. A detailed analysis of the interaction of the electromagnetic wave with the material showed that a strong ponderomotive force preferentially separates the constituent phases via an enhanced mass transport process amplified particularly near the interfaces. The proof of concept experiments showed that the material, whether it is a solid-solution of two elements, e.g. (Si 1-x Ge x ), or two compounds, e.g. (Bi 2 Te 3 ) 1-x (Sb 2 Te 3 ) x , decomposes into the constituent phases when radiated by a polarized microwave field. The dissolution happens in the bulk of the material and even below the melting point. The degree of decomposition can be controlled by radiation parameters to produce structures composed of gradient phases of the solid-solution. This offers a novel and facile method for synthesizing gradient composite and complex structures for application in thermoelectricity as well as fabrication of core-shell structures for catalysts and biomedical applications.}, journal={ACTA MATERIALIA}, author={Nozariasbmarz, Amin and Hosseini, Mahshid and Vashaee, Daryoosh}, year={2019}, month={Oct}, pages={85–92} }
@article{nozariasbmarz_krasinski_vashaee_2019, title={N-Type Bismuth Telluride Nanocomposite Materials Optimization for Thermoelectric Generators in Wearable Applications}, volume={12}, ISSN={["1996-1944"]}, DOI={10.3390/ma12091529}, abstractNote={Thermoelectric materials could play a crucial role in the future of wearable electronic devices. They can continuously generate electricity from body heat. For efficient operation in wearable systems, in addition to a high thermoelectric figure of merit, zT, the thermoelectric material must have low thermal conductivity and a high Seebeck coefficient. In this study, we successfully synthesized high-performance nanocomposites of n-type Bi2Te2.7Se0.3, optimized especially for body heat harvesting and power generation applications. Different techniques such as dopant optimization, glass inclusion, microwave radiation in a single mode microwave cavity, and sintering conditions were used to optimize the temperature-dependent thermoelectric properties of Bi2Te2.7Se0.3. The effects of these techniques were studied and compared with each other. A room temperature thermal conductivity as low as 0.65 W/mK and high Seebeck coefficient of −297 μV/K were obtained for a wearable application, while maintaining a high thermoelectric figure of merit, zT, of 0.87 and an average zT of 0.82 over the entire temperature range of 25 °C to 225 °C, which makes the material appropriate for a variety of power generation applications.}, number={9}, journal={MATERIALS}, author={Nozariasbmarz, Amin and Krasinski, Jerzy S. and Vashaee, Daryoosh}, year={2019}, month={May} }
@article{zheng_lu_polash_rasoulianboroujeni_liu_manley_deng_sun_chen_hermann_et al._2019, title={Paramagnon drag in high thermoelectric figure of merit Li-doped MnTe}, volume={5}, ISSN={["2375-2548"]}, url={https://doi.org/10.1126/sciadv.aat9461}, DOI={10.1126/sciadv.aat9461}, abstractNote={Neutrons spot magnetic fluctuations that propel charges in a novel class of paramagnetic thermoelectrics.}, number={9}, journal={SCIENCE ADVANCES}, publisher={American Association for the Advancement of Science (AAAS)}, author={Zheng, Y. and Lu, T. and Polash, Md M. H. and Rasoulianboroujeni, M. and Liu, N. and Manley, M. E. and Deng, Y. and Sun, P. J. and Chen, X. L. and Hermann, R. P. and et al.}, year={2019}, month={Sep} }
@article{akbarzadeh_ghaedi_kokhdan_vashaee_2019, title={Remarkably improved electrochemical hydrogen storage by multi-walled carbon nanotubes decorated with nanoporous bimetallic Fe-Ag/TiO2 nanoparticles}, volume={48}, ISSN={["1477-9234"]}, DOI={10.1039/c8dt03897j}, abstractNote={Nanoporous bimetallic Fe-Ag nanoparticles (NPs) were synthesized using a facile chemical reduction method and used to decorate the surface of multi-walled carbon nanotubes (MWCNTs) for hydrogen sorption and storage. The effect of TiO2 nanoparticles on the hydrogen storage properties of Fe-Ag/CNTs was further studied in detail. For this purpose, several nanocomposites of nanoporous bimetallic Fe-Ag/TiO2 nanoparticles with different amounts of bimetallic Fe-Ag NPs were prepared via a hydrothermal method. The hydrogen storage capacity of the as-prepared nanocomposites was studied using electrochemical methods. The Fe-Ag/TiO2/CNT nanocomposite with 0.04 M bimetallic Fe-Ag NPs showed the highest capacity for hydrogen storage, which was ∼5× higher than that of pristine MWCNTs. The maximum discharge capacity was 2931 mA h g-1, corresponding to a 10.94 wt% hydrogen storage capacity. Furthermore, a 379% increase in discharge capacity was measured after 20 cycles. These results show that Fe-Ag/TiO2/CNT electrodes display superior cycling stability and high reversible capacity, which is attractive for battery applications.}, number={3}, journal={DALTON TRANSACTIONS}, author={Akbarzadeh, Raziyeh and Ghaedi, Mehrorang and Kokhdan, Syamak Nasiri and Vashaee, Daryoosh}, year={2019}, month={Jan}, pages={898–907} }
@misc{zaferani_ghomashchi_vashaee_2019, title={Strategies for engineering phonon transport in Heusler thermoelectric compounds}, volume={112}, ISSN={["1879-0690"]}, DOI={10.1016/j.rser.2019.05.051}, abstractNote={Thermoelectric generators, which can convert waste heat directly into electricity, are promising candidates for capturing low-grade heat and enhancing the efficiency of the heat engines. This would lead to decreasing the fossil fuel usage and greenhouse gas emission. Many Heusler compounds have been studied for thermoelectric application due to their desired characteristics such as sizeable thermoelectric power factor, non-toxicity, and high stability over a wide temperature range. The primary restriction for Heusler thermoelectric materials has been their high lattice thermal conductivity, which reduces their thermoelectric figure of merit. Several strategies have been carried out to ameliorate this restriction by engineering the phonon transport properties. This article discusses several approaches such as bulk nanostructuring, the creation of point defects and vacancies, impurity doping, and multiphase engineering of the material structure for reducing the thermal conductivity of the Heusler compounds. The effectiveness of each of these methods depends on temperature; hence, the working temperature must be taken into account when designing the material structure and the composition to achieve the optimum performance for practical applications.}, journal={RENEWABLE & SUSTAINABLE ENERGY REVIEWS}, author={Zaferani, Sadeq Hooshmand and Ghomashchi, Reza and Vashaee, Daryoosh}, year={2019}, month={Sep}, pages={158–169} }
@article{monico_tahriri_fahmy_ghassemi_vashaee_tayebi_2018, title={Cartilage and facial muscle tissue engineering and regeneration: a mini review}, volume={1}, ISSN={2096-5524 2522-8552}, url={http://dx.doi.org/10.1007/s42242-018-0011-4}, DOI={10.1007/s42242-018-0011-4}, number={2}, journal={Bio-Design and Manufacturing}, publisher={Springer Science and Business Media LLC}, author={Monico, Michael Del and Tahriri, Mohammadreza and Fahmy, Mina D. and Ghassemi, Hamed and Vashaee, Daryoosh and Tayebi, Lobat}, year={2018}, month={May}, pages={115–122} }
@article{fahimipour_dashtimoghadam_rasoulianboroujeni_yazdimamaghani_khoshroo_tahriri_yadegari_gonzalez_vashaee_lobner_et al._2018, title={Collagenous matrix supported by a 3D-printed scaffold for osteogenic differentiation of dental pulp cells}, volume={34}, ISSN={0109-5641}, url={http://dx.doi.org/10.1016/j.dental.2017.10.001}, DOI={10.1016/j.dental.2017.10.001}, abstractNote={A systematic characterization of hybrid scaffolds, fabricated based on combinatorial additive manufacturing technique and freeze-drying method, is presented as a new platform for osteoblastic differentiation of dental pulp cells (DPCs). The scaffolds were consisted of a collagenous matrix embedded in a 3D-printed beta-tricalcium phosphate (β-TCP) as the mineral phase. The developed construct design was intended to achieve mechanical robustness owing to 3D-printed β-TCP scaffold, and biologically active 3D cell culture matrix pertaining to the Collagen extracellular matrix. The β-TCP precursor formulations were investigated for their flow-ability at various temperatures, which optimized for fabrication of 3D printed scaffolds with interconnected porosity. The hybrid constructs were characterized by 3D laser scanning microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and compressive strength testing. The in vitro characterization of scaffolds revealed that the hybrid β-TCP/Collagen constructs offer superior DPCs proliferation and alkaline phosphatase (ALP) activity compared to the 3D-printed β-TCP scaffold over three weeks. Moreover, it was found that the incorporation of TCP into the Collagen matrix improves the ALP activity. The presented results converge to suggest the developed 3D-printed β-TCP/Collagen hybrid constructs as a new platform for osteoblastic differentiation of DPCs for craniomaxillofacial bone regeneration.}, number={2}, journal={Dental Materials}, publisher={Elsevier BV}, author={Fahimipour, Farahnaz and Dashtimoghadam, Erfan and Rasoulianboroujeni, Morteza and Yazdimamaghani, Mostafa and Khoshroo, Kimia and Tahriri, Mohammadreza and Yadegari, Amir and Gonzalez, Jose A. and Vashaee, Daryoosh and Lobner, Douglas C. and et al.}, year={2018}, month={Feb}, pages={209–220} }
@article{parsa_vafajoo_rostami_salarian_rabiee_rabiee_rabiee_tahriri_yadegari_vashaee_et al._2018, title={Early diagnosis of disease using microbead array technology: A review}, volume={1032}, ISSN={0003-2670}, url={http://dx.doi.org/10.1016/j.aca.2018.05.011}, DOI={10.1016/j.aca.2018.05.011}, abstractNote={Early diagnosis of diseases (before they become advanced and incurable) is essential to reduce morbidity and mortality rates. With the advent of novel technologies in clinical laboratory diagnosis, microbead-based arrays have come to be recognized as an efficient approach, that demonstrates useful advantages over traditional assay methods for multiple disease-related biomarkers. Multiplexed microbead assays provide a robust, rapid, specific, and cost-effective approach for high-throughput and simultaneous screening of many different targets. Biomolecular binding interactions occur after applying a biological sample (such as blood plasma, saliva, cerebrospinal fluid etc.) containing the target analyte(s) to a set of microbeads with different ligand-specificities that have been coded in planar or suspension arrays. The ligand-receptor binding activity is tracked by optical signals generated by means of flow cytometry analysis in the case of suspension arrays, or by image processing devices in the case of planar arrays. In this review paper, we discuss diagnosis of cancer, neurological and infectious diseases by using optically-encoded microbead-based arrays (both multiplexed and single-analyte assays) as a reliable tool for detection and quantification of various analytes.}, journal={Analytica Chimica Acta}, publisher={Elsevier BV}, author={Parsa, Sanam Foroutan and Vafajoo, Atieh and Rostami, Azin and Salarian, Reza and Rabiee, Mohammad and Rabiee, Navid and Rabiee, Ghazal and Tahriri, Mohammadreza and Yadegari, Amir and Vashaee, Daryoosh and et al.}, year={2018}, month={Nov}, pages={1–17} }
@article{nozariasbmarz_dsouza_vashaee_2018, title={Field induced decrystallization of silicon: Evidence of a microwave non-thermal effect}, volume={112}, ISSN={0003-6951 1077-3118}, url={http://dx.doi.org/10.1063/1.5020192}, DOI={10.1063/1.5020192}, abstractNote={It is rather strange and not fully understood that some materials decrystallize when exposed to microwave radiation, and it is still debatable if such a transformation is a thermal or non-thermal effect. We hereby report experimental evidences that weight the latter effect. First, a single crystal silicon wafer exposed to microwaves showed strong decrystallization at high temperature. Second, when some areas of the wafer were masked with metal coating, only the exposed areas underwent decrystallization. Transmission electron microscopy analysis, x-ray diffraction data, and thermal conductivity measurements all indicated strong decrystallization, which occurred in the bulk of the material and was not a surface effect. These observations favor the existence of a non-thermal microwave effect.}, number={9}, journal={Applied Physics Letters}, publisher={AIP Publishing}, author={Nozariasbmarz, Amin and Dsouza, Kelvin and Vashaee, Daryoosh}, year={2018}, month={Feb}, pages={093103} }
@article{razavi_fathi_savabi_tayebi_vashaee_2018, title={Improvement of in vitro behavior of an Mg alloy using a nanostructured composite bioceramic coating}, volume={29}, ISSN={["1573-4838"]}, DOI={10.1007/s10856-018-6170-1}, number={10}, journal={JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE}, author={Razavi, Mehdi and Fathi, Mohammadhossein and Savabi, Omid and Tayebi, Lobat and Vashaee, Daryoosh}, year={2018}, month={Oct} }
@article{vafajoo_rostami_foroutan parsa_salarian_rabiee_rabiee_rabiee_tahriri_vashaee_tayebi_et al._2018, title={Multiplexed microarrays based on optically encoded microbeads}, volume={20}, ISSN={1387-2176 1572-8781}, url={http://dx.doi.org/10.1007/S10544-018-0314-4}, DOI={10.1007/S10544-018-0314-4}, abstractNote={In recent years, there has been growing interest in optically-encoded or tagged functionalized microbeads as a solid support platform to capture proteins or nucleotides which may serve as biomarkers of various diseases. Multiplexing technologies (suspension array or planar array) based on optically encoded microspheres have made possible the observation of relatively minor changes in biomarkers related to specific diseases. The ability to identify these changes at an early stage may allow the diagnosis of serious diseases (e.g. cancer) at a time-point when curative treatment may still be possible. As the overall accuracy of current diagnostic methods for some diseases is often disappointing, multiplexed assays based on optically encoded microbeads could play an important role to detect biomarkers of diseases in a non-invasive and accurate manner. However, detection systems based on functionalized encoded microbeads are still an emerging technology, and more research needs to be done in the future. This review paper is a preliminary attempt to summarize the state-of-the-art concerning diagnostic microbeads; including microsphere composition, synthesis, encoding technology, detection systems, and applications.}, number={3}, journal={Biomedical Microdevices}, publisher={Springer Science and Business Media LLC}, author={Vafajoo, Atieh and Rostami, Azin and Foroutan Parsa, Sanam and Salarian, Reza and Rabiee, Navid and Rabiee, Ghazal and Rabiee, Mohammad and Tahriri, Mohammadreza and Vashaee, Daryoosh and Tayebi, Lobat and et al.}, year={2018}, month={Aug} }
@article{norouzzadeh_ede_vashaee_2018, title={The effect of nanostructuring on the spectral population of electrons and phonons}, volume={753}, ISSN={["1873-4669"]}, DOI={10.1016/j.jallcom.2018.04.243}, abstractNote={Abstract A detailed analysis of the spectral population of electrons and phonons in nanostructured materials is presented. It is found that, in addition to the general notion that in nanostructured materials the electrons and phonons mean free paths (MFP) reduce, their populations per mean free path, however, may increase in some ranges of the MFP in some materials. In such cases, the electrical conductivity for a given electron MFP can increase upon nanostructuring; however, the corresponding thermal conductivity does not change significantly. These new understandings can elucidate why nanostructuring does not considerably enhance the thermoelectric figure of merit of some materials. In order to demonstrate these implications, the thermal and electrical properties of three sample materials with different trends were studied and compared. The results are presented in a form that can be validated by the existing thermal conductivity spectroscopy techniques.}, journal={JOURNAL OF ALLOYS AND COMPOUNDS}, author={Norouzzadeh, Payam and Ede, Kenneth F. and Vashaee, Daryoosh}, year={2018}, month={Jul}, pages={234–238} }
@article{sanaeifar_rabiee_abdolrahim_tahriri_vashaee_tayebi_2017, title={A novel electrochemical biosensor based on Fe 3 O 4 nanoparticles-polyvinyl alcohol composite for sensitive detection of glucose}, volume={519}, ISSN={0003-2697}, url={http://dx.doi.org/10.1016/j.ab.2016.12.006}, DOI={10.1016/j.ab.2016.12.006}, abstractNote={In this research, a new electrochemical biosensor was constructed for the glucose detection. Iron oxide nanoparticles (Fe3O4) were synthesized through co-precipitation method. Polyvinyl alcohol-Fe3O4 nanocomposite was prepared by dispersing synthesized nanoparticles in the polyvinyl alcohol (PVA) solution. Glucose oxidase (GOx) was immobilized on the PVA-Fe3O4 nanocomposite via physical adsorption. The mixture of PVA, Fe3O4 nanoparticles and GOx was drop cast on a tin (Sn) electrode surface (GOx/PVA-Fe3O4/Sn). The Fe3O4 nanoparticles were characterized by X-ray diffraction (XRD). Also, Fourier transform infrared (FTIR) spectroscopy and field emission scanning electron microscopy (FE-SEM) techniques were utilized to evaluate the PVA-Fe3O4 and GOx/PVA-Fe3O4 nanocomposites. The electrochemical performance of the modified biosensor was investigated using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Presence of Fe3O4 nanoparticles in the PVA matrix enhanced the electron transfer between enzyme and electrode surface and the immobilized GOx showed excellent catalytic characteristic toward glucose. The GOx/PVA-Fe3O4/Sn bioelectrode could measure glucose in the range from 5 × 10-3 to 30 mM with a sensitivity of 9.36 μA mM-1 and exhibited a lower detection limit of 8 μM at a signal-to-noise ratio of 3. The value of Michaelis-Menten constant (KM) was calculated as 1.42 mM. The modified biosensor also has good anti-interfering ability during the glucose detection, fast response (10 s), good reproducibility and satisfactory stability. Finally, the results demonstrated that the GOx/PVA-Fe3O4/Sn bioelectrode is promising in biosensor construction.}, journal={Analytical Biochemistry}, publisher={Elsevier BV}, author={Sanaeifar, Niuosha and Rabiee, Mohammad and Abdolrahim, Mojgan and Tahriri, Mohammadreza and Vashaee, Daryoosh and Tayebi, Lobat}, year={2017}, month={Feb}, pages={19–26} }
@inbook{omidi_fatehinya_farahani_akbari_shahmoradi_yazdian_tahriri_moharamzadeh_tayebi_vashaee_2017, title={Characterization of biomaterials}, ISBN={9780081009611}, url={http://dx.doi.org/10.1016/b978-0-08-100961-1.00007-4}, DOI={10.1016/b978-0-08-100961-1.00007-4}, abstractNote={Recent advances in the development of the characterization tools have remarkably facilitated the biomaterials research. However, recognizing the correct set of tools from the bewildering number of the existing instruments may indeed be another challenge. Since these various instruments and techniques can be utilized for variety of different applications, appropriate selection of the characterization tools can spare significantly both time and resources. In fact, characterization of biomaterials can be quite multidisciplinary relying on chemical, physical, mechanical, or biological tools, and techniques. This chapter is prepared to help the interdisciplinary oral and dental researchers in recognizing the existing instruments and techniques and to facilitate the development and discovery of new materials and extending their applications in engineering of oral and dental tissues.}, booktitle={Biomaterials for Oral and Dental Tissue Engineering}, publisher={Elsevier}, author={Omidi, Meisam and Fatehinya, Atena and Farahani, Masomeh and Akbari, Zahra and Shahmoradi, Saleheh and Yazdian, Fatemeh and Tahriri, Mohammadreza and Moharamzadeh, Keyvan and Tayebi, Lobat and Vashaee, Daryoosh}, year={2017}, pages={97–115} }
@article{rasoulianboroujeni_kupgan_moghadam_tahriri_boughdachi_khoshkenar_ambrose_kiaie_vashaee_ramsey_et al._2017, title={Development of a DNA-liposome complex for gene delivery applications}, volume={75}, ISSN={0928-4931}, url={http://dx.doi.org/10.1016/j.msec.2017.02.012}, DOI={10.1016/j.msec.2017.02.012}, abstractNote={The association structures formed by cationic liposomes and DNA (Deoxyribonucleic acid)-liposome have been effectively utilized as gene carriers in transfection assays. In this research study, cationic liposomes were prepared using a modified lipid film hydration method consisting of a lyophilization step for gene delivery applications. The obtained results demonstrated that the mean particle size had no significant change while the polydispersity (PDI) increased after lyophilization. The mean particle size slightly reduced after lyophilization (520±12nm to 464±25nm) while the PDI increased after lyophilization (0.094±0.017 to 0.220±0.004). In addition. The mean particle size of vesicles increases when DNA is incorporated to the liposomes (673±27nm). According to the Scanning Electron Microscopy (SEM) and transmission electron microscopy (TEM) images, the spherical shape of liposomes confirmed their successful preservation and reconstitution from the powder. It was found that liposomal formulation has enhanced transfection considerably compared to the naked DNA as negative control. Finally, liposomal formulation in this research had a better function than Lipofectamine® 2000 as a commercialized product because the cellular activity (cellular protein) was higher in the prepared lipoplex than Lipofectamine® 2000.}, journal={Materials Science and Engineering: C}, publisher={Elsevier BV}, author={Rasoulianboroujeni, M. and Kupgan, G. and Moghadam, F. and Tahriri, M. and Boughdachi, A. and Khoshkenar, P. and Ambrose, J.J. and Kiaie, N. and Vashaee, D. and Ramsey, J.D. and et al.}, year={2017}, month={Jun}, pages={191–197} }
@article{narendra_norouzzadeh_vashaee_kim_2017, title={Doping induced enhanced density of states in bismuth telluride}, volume={111}, ISSN={0003-6951 1077-3118}, url={http://dx.doi.org/10.1063/1.4989602}, DOI={10.1063/1.4989602}, abstractNote={Power factor enhancement through resonant doping is explored in Bi2Te3 based on a detailed first-principles study. Of the dopant atoms investigated, it is found that the formation of resonant states may be achieved with In, Po, and Na, leading potentially to a significant increase in the thermoelectric efficiency at room temperature. While doping with Po forms twin resonant state peaks in the valence and conduction bands, the incorporation of Na or In results in the resonant states close to the valence band edge. Further analysis reveals the origin of these resonant states. Transport calculations are also carried out to estimate the anticipated level of enhancement.}, number={23}, journal={Applied Physics Letters}, publisher={AIP Publishing}, author={Narendra, Namita and Norouzzadeh, Payam and Vashaee, Daryoosh and Kim, Ki Wook}, year={2017}, month={Dec}, pages={232101} }
@article{santos_dou_vashaee_yamini_2017, title={Effect of the Fabrication Technique on the Thermoelectric Performance of Mg-Based Compounds-A Case Study of n-Type Mg2Ge}, volume={2}, ISSN={["2470-1343"]}, DOI={10.1021/acsomega.7b01389}, abstractNote={High performance, low cost, and low toxicity have been the main characteristics associated with magnesium-based thermoelectric materials. Nevertheless, the high volatility of magnesium creates challenges in the synthesis of these materials. In this work, n-type Mg2Ge is synthesized using a solid-state technique, fully characterized, and compared with Mg2Ge fabricated through different processes. We have found that Bi is an ineffective dopant in Mg2Ge and precipitates into Mg2Bi3. Regardless of the technique used, the loss of Mg by evaporation and formation of precipitates in Bi-doped samples resulted in a low charge carrier concentration and, consequently, a low power factor. The precipitates significantly reduced the lattice thermal conductivity, however, leading to a figure-of-merit, zT, of 0.4 at 725 K, improving the previously reported figure-of-merit, zT, of 0.2 for Sb-doped Mg2Ge. This work highlights the impact of the fabrication technique on the thermoelectric performance of Mg-based compounds.}, number={11}, journal={ACS OMEGA}, author={Santos, Rafael and Dou, Shi Xue and Vashaee, Daryoosh and Yamini, Sima Aminorroaya}, year={2017}, month={Nov}, pages={8069–8074} }
@article{suarez_parekh_ladd_vashaee_dickey_öztürk_2017, title={Flexible thermoelectric generator using bulk legs and liquid metal interconnects for wearable electronics}, volume={202}, ISSN={0306-2619}, url={http://dx.doi.org/10.1016/j.apenergy.2017.05.181}, DOI={10.1016/j.apenergy.2017.05.181}, abstractNote={Abstract Interest in wearable electronics for continuous, long-term health and performance monitoring is rapidly increasing. The reduction in power levels consumed by sensors and electronic circuits accompanied by the advances in energy harvesting methods allows for the realization of self-powered monitoring systems that do not have to rely on batteries. For wearable electronics, thermoelectric generators (TEGs) offer the unique ability to continuously convert body heat into usable energy. For body harvesting, it is preferable to have TEGs that are thin, soft and flexible. Unfortunately, the performances of flexible modules reported to date have been far behind those of their rigid counterparts. This is largely due to lower efficiencies of the thermoelectric materials, electrical or thermal parasitic losses and limitations on leg dimensions posed by the synthesis techniques. In this work, we present an entirely new approach and explore the possibility of using standard bulk legs in a flexible package. Bulk thermoelectric legs cut from solid ingots are far superior to thermoelectric materials synthesized using other techniques. A key enabler of the proposed technology is the use of EGaIn liquid metal interconnects, which not only provide extremely low interconnect resistance but also stretchability with self-healing, both of which are essential for flexible TE modules. The results suggest that this novel approach can finally produce flexible TEGs that have the potential to challenge the rigid TEGs and provide a pathway for the realization of self-powered wearable electronics.}, journal={Applied Energy}, publisher={Elsevier BV}, author={Suarez, Francisco and Parekh, Dishit P. and Ladd, Collin and Vashaee, Daryoosh and Dickey, Michael D. and Öztürk, Mehmet C.}, year={2017}, month={Sep}, pages={736–745} }
@article{rasoulianboroujeni_yazdimamaghani_khoshkenar_pothineni_kim_murray_rajadas_mills_vashaee_moharamzadeh_et al._2017, title={From solvent-free microspheres to bioactive gradient scaffolds}, volume={13}, ISSN={["1549-9642"]}, DOI={10.1016/j.nano.2016.10.008}, abstractNote={A solvent-free microsphere sintering technique was developed to fabricate scaffolds with pore size gradient for tissue engineering applications. Poly(D,L-Lactide) microspheres were fabricated through an emulsification method where TiO2 nanoparticles were employed both as particulate emulsifier in the preparation procedure and as surface modification agent to improve bioactivity of the scaffolds. A fine-tunable pore size gradient was achieved with a pore volume of 30 ± 2.6%. SEM, EDX, XRD and FTIR analyses all confirmed the formation of bone-like apatite at the 14th day of immersion in Simulated Body Fluid (SBF) implying the ability of our scaffolds to bond to living bone tissue. In vitro examination of the scaffolds showed progressive activity of the osteoblasts on the scaffold with evidence of increase in its mineral content. The bioactive scaffold developed in this study has the potential to be used as a suitable biomaterial for bone tissue engineering and hard tissue regeneration.}, number={3}, journal={NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE}, author={Rasoulianboroujeni, Morteza and Yazdimamaghani, Mostafa and Khoshkenar, Payam and Pothineni, Venkata Raveendra and Kim, Kwang Min and Murray, Teresa A. and Rajadas, Jayakumar and Mills, David K. and Vashaee, Daryoosh and Moharamzadeh, Keyvan and et al.}, year={2017}, month={Apr}, pages={1157–1169} }
@article{norouzzadeh_myles_vashaee_2017, title={Phonon dynamics in type-VIII silicon clathrates: Beyond the rattler concept}, volume={95}, ISSN={["2469-9969"]}, DOI={10.1103/physrevb.95.195206}, abstractNote={Clathrates can form a type of guest-host solid structures that, unlike most crystalline solids, have very low thermal conductivity. It is generally thought that the guest atoms caged inside the host framework act as ``rattlers'' and induce lattice dynamics disorders responsible for the small thermal conductivity. We performed a systematic study of the lattice dynamical properties of type-VIII clathrates with alkali and alkaline-earth guests, i.e., ${X}_{8}\mathrm{S}{\mathrm{i}}_{46}$ ($X=\mathrm{Na}$, K, Rb, Cs, Ca, Sr, and Ba). The energy dependent participation ratio (PR) and the atomic participation ratio of phonon modes extracted from density functional theory calculations revealed that the rattler concept is not adequate to describe the effect of fillers as they manifest strong hybridization with the framework. For the case of heavy fillers, such as Rb, Sr, Cs, and Ba, a phonon band gap was formed between the acoustic and optical branches. The calculated PR indicated that the fillers suppress the acoustic phonon modes and change the energy transport mechanism from propagative to diffusive or localized resulting in ``phonon-glass'' characteristics. This effect is stronger for the heavy fillers. Furthermore, in all cases, the guest insertion depressed the phonon bandwidth, reduced the Debye temperature, and reduced the phonon group velocity, all of which should lead to reduction of the thermal conductivity.}, number={19}, journal={PHYSICAL REVIEW B}, author={Norouzzadeh, Payam and Myles, Charles W. and Vashaee, Daryoosh}, year={2017}, month={May} }
@misc{yazdimamaghani_razavi_vashaee_moharamzadeh_boccaccini_tayebi_2017, title={Porous magnesium-based scaffolds for tissue engineering}, volume={71}, ISSN={["1873-0191"]}, DOI={10.1016/j.msec.2016.11.027}, abstractNote={Significant amount of research efforts have been dedicated to the development of scaffolds for tissue engineering. Although at present most of the studies are focused on non-load bearing scaffolds, many scaffolds have also been investigated for hard tissue repair. In particular, metallic scaffolds are being studied for hard tissue engineering due to their suitable mechanical properties. Several biocompatible metallic materials such as stainless steels, cobalt alloys, titanium alloys, tantalum, nitinol and magnesium alloys have been commonly employed as implants in orthopedic and dental treatments. They are often used to replace and regenerate the damaged bones or to provide structural support for healing bone defects. Among the common metallic biomaterials, magnesium (Mg) and a number of its alloys are effective because of their mechanical properties close to those of human bone, their natural ionic content that may have important functional roles in physiological systems, and their in vivo biodegradation characteristics in body fluids. Due to such collective properties, Mg based alloys can be employed as biocompatible, bioactive, and biodegradable scaffolds for load-bearing applications. Recently, porous Mg and Mg alloys have been specially suggested as metallic scaffolds for bone tissue engineering. With further optimization of the fabrication techniques, porous Mg is expected to make a promising hard substitute scaffold. The present review covers research conducted on the fabrication techniques, surface modifications, properties and biological characteristics of Mg alloys based scaffolds. Furthermore, the potential applications, challenges and future trends of such degradable metallic scaffolds are discussed in detail.}, journal={MATERIALS SCIENCE & ENGINEERING C-MATERIALS FOR BIOLOGICAL APPLICATIONS}, author={Yazdimamaghani, Mostafa and Razavi, Mehdi and Vashaee, Daryoosh and Moharamzadeh, Keyvan and Boccaccini, Aldo R. and Tayebi, Lobat}, year={2017}, month={Feb}, pages={1253–1266} }
@article{tavakkoli yaraki_tayebi_ahmadieh_tahriri_vashaee_tayebi_2017, title={Synthesis and optical properties of cysteamine-capped ZnS quantum dots for aflatoxin quantification}, volume={690}, ISSN={0925-8388}, url={http://dx.doi.org/10.1016/j.jallcom.2016.08.158}, DOI={10.1016/j.jallcom.2016.08.158}, abstractNote={Abstract Water-soluble cysteamine-capped ZnS quantum dots (QDs) are designed to serve as a photodetector for a dangerous group of carcinogens called aflatoxins. ZnS QDs are synthesized by growth in a poly(vinyl alcohol) matrix using the precipitation method. The prepared QDs are characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Our characterization shows that these ZnS QDs have a 1.77 nm crystalline size, cubic zinc blende structure and spherical morphology with a diameter less than 10 nm. Photoluminescence spectroscopy (PL) is performed in the presence of a standard solution of aflatoxins (B1, B2, G1 and G2 with a ratio of 5:1:5:1) at various concentrations, in order to determine the efficacy of a ZnS QD-based aflatoxin detection method. Two PL emission peaks located at 440 nm and 467 nm are observed whose intensities are enhanced by increasing the concentration of total aflatoxin. PL variations in the range of aflatoxin concentrations studied here (2.4 ppb–48 ppb) are best described by a Langmuir-type equation. The limit of detection is calculated to be 0.05 ppb, well below the lowest international contamination allowance in food products.}, journal={Journal of Alloys and Compounds}, publisher={Elsevier BV}, author={Tavakkoli Yaraki, Mohammad and Tayebi, Mahnoush and Ahmadieh, Mahnaz and Tahriri, Mohammadreza and Vashaee, Daryoosh and Tayebi, Lobat}, year={2017}, month={Jan}, pages={749–758} }
@misc{nozariasbmarz_agarwal_coutant_hall_liu_liu_malhotra_norouzzadeh_oeztuerk_ramesh_et al._2017, title={Thermoelectric silicides: A review}, volume={56}, ISSN={["1347-4065"]}, url={http://dx.doi.org/10.7567/jjap.56.05da04}, DOI={10.7567/jjap.56.05da04}, number={5}, journal={JAPANESE JOURNAL OF APPLIED PHYSICS}, author={Nozariasbmarz, Amin and Agarwal, Aditi and Coutant, Zachary A. and Hall, Michael J. and Liu, Jie and Liu, Runze and Malhotra, Abhishek and Norouzzadeh, Payam and Oeztuerk, Mehmet C. and Ramesh, Viswanath P. and et al.}, year={2017}, month={May} }
@article{namvar_salahinejad_saberi_jafari baghjeghaz_tayebi_vashaee_2017, title={Toward reducing the formation temperature of diopside via wet-chemical synthesis routes using chloride precursors}, volume={43}, ISSN={0272-8842}, url={http://dx.doi.org/10.1016/j.ceramint.2017.07.094}, DOI={10.1016/j.ceramint.2017.07.094}, abstractNote={Reducing the formation temperature of single-phase multioxides is one of the classic challenges in ceramic processing, including wet-chemical synthesis routes. Toward pursuing this aim for diopside (MgCaSi2O6), the merit of different sol-gel and coprecipitation processes using the related chloride precursors followed by calcination was compared from the viewpoints of crystallinity and homogeneity. In accordance to the results, the use of the sol-gel techniques, directed with/without an alkaline catalyst, gave rise to the unfavorable creation of multiphase and low-crystallinity structures. Regarding the coprecipitation methods, the one-step addition of a precipitant agent is accompanied by an indirect low-temperature formation of nano-diopside, while a direct crystallization into this phase was explored in the dropwise condition, albeit with a lower crystallinity. Thus, by employing a suitable synthesis processing, it is feasible to take control of a wide range of nanoparticulate diopside-based structures achieved after a low-temperature calcination.}, number={16}, journal={Ceramics International}, publisher={Elsevier BV}, author={Namvar, N. and Salahinejad, E. and Saberi, A.H. and Jafari Baghjeghaz, M. and Tayebi, L. and Vashaee, D.}, year={2017}, month={Nov}, pages={13781–13785} }
@article{norouzzadeh_shakouri_vashaee_2017, title={Valleytronics of III–V solid solutions for thermoelectric application}, volume={7}, ISSN={2046-2069}, url={http://dx.doi.org/10.1039/C6RA28280F}, DOI={10.1039/C6RA28280F}, abstractNote={It is shown that the degeneracy of the bandstructure has different impacts on thermoelectric properties of III–V materials.}, number={12}, journal={RSC Advances}, publisher={Royal Society of Chemistry (RSC)}, author={Norouzzadeh, Payam and Shakouri, Ali and Vashaee, Daryoosh}, year={2017}, pages={7310–7314} }
@inproceedings{williams_kraus_riley_2016, title={Amending pine bark with swine lagoon compost: is poo the answer?(c)(a)}, volume={1140}, booktitle={Proceedings of the 2015 annual meeting of the international plant propagators' society}, author={Williams, M. T. and Kraus, H. T. and Riley, E. D.}, year={2016}, pages={371–375} }
@article{norouzzadeh_vashaee_2016, title={Classification of Valleytronics in Thermoelectricity}, volume={6}, ISSN={2045-2322}, url={http://dx.doi.org/10.1038/srep22724}, DOI={10.1038/srep22724}, abstractNote={The theory of valleytronics as a material design tool for engineering both thermal and electrical transport properties is presented. It is shown that the interplay among the valleytronics parameters such as the degeneracy of the band, intervalley transitions, effective mass, scattering exponent, and the Fermi energy may deteriorate or ameliorate any or all of the main thermoelectric properties. A flowchart classifying the different paths through which the valleytronics can influence the thermoelectric figure-of-merit ZT is derived and discussed in detail. To exemplify the application of the flowchart, valleytronics in four different semiconductors, Mg2Si, Si0.8Ge0.2, Al(x)Ga(1-x)As and clathrate Si46-VIII were studied, which showed different trends. Therefore, a degenerate multivalley bandstructure, which is typically anticipated for a good thermoelectric material, cannot be a general design rule for ZT enhancement and a detailed transport study is required to engineer the optimum bandstructure.}, number={1}, journal={Scientific Reports}, publisher={Springer Science and Business Media LLC}, author={Norouzzadeh, Payam and Vashaee, Daryoosh}, year={2016}, month={Mar} }
@article{nozariasbmarz_roy_zamanipour_dycus_cabral_lebeau_krasinski_vashaee_2016, title={Comparison of thermoelectric properties of nanostructured Mg2Si, FeSi2, SiGe, and nanocomposites of SiGe-Mg2Si, SiGe-FeSi2}, volume={4}, ISSN={["2166-532X"]}, DOI={10.1063/1.4966138}, abstractNote={Thermoelectric properties of nanostructured FeSi2, Mg2Si, and SiGe are compared with their nanocomposites of SiGe–Mg2Si and SiGe–FeSi2. It was found that the addition of silicide nanoinclusions to SiGe alloy maintained or increased the power factor while further reduced the thermal conductivity compared to the nanostructured single-phase SiGe alloy. This resulted in ZT enhancement of Si0.88Ge0.12–FeSi2 by ∼30% over the broad temperature range of 500-950 °C compared to the conventional Si0.80Ge0.20 alloy. The Si0.88Ge0.12–Mg2Si nanocomposite showed constantly increasing ZT versus temperature up to 950 °C (highest measured temperature) reaching ZT ∼ 1.3. These results confirm the concept of silicide nanoparticle-in-SiGe-alloy proposed earlier by Mingo et al. [Nano Lett. 9, 711–715 (2009)].}, number={10}, journal={APL MATERIALS}, author={Nozariasbmarz, Amin and Roy, Palash and Zamanipour, Zahra and Dycus, J. Houston and Cabral, Matthew J. and LeBeau, James M. and Krasinski, Jerzy S. and Vashaee, Daryoosh}, year={2016}, month={Oct} }
@inbook{yazdimamaghani_davachi_amrollahi_vashaee_tayebi_2016, title={Conducting Polymers: Developments}, ISBN={1439898790 1466501790}, url={http://dx.doi.org/10.1081/e-ebpp-120050030}, DOI={10.1081/e-ebpp-120050030}, booktitle={Encyclopedia of Biomedical Polymers and Polymeric Biomaterials}, publisher={Taylor & Francis}, author={YazdiMamaghani, Mostafa and Davachi, Seyed Mohammad and Amrollahi, Pouya and Vashaee, Daryoosh and Tayebi, Lobat}, year={2016}, month={Jan}, pages={1997–2010} }
@article{suarez_nozariasbmarz_vashaee_ozturk_2016, title={Designing thermoelectric generators for self-powered wearable electronics}, volume={9}, ISSN={["1754-5706"]}, DOI={10.1039/c6ee00456c}, abstractNote={Computational efficient, quasi-3D model for designing body wearable thermoelectric generators and experimental verification.}, number={6}, journal={ENERGY & ENVIRONMENTAL SCIENCE}, author={Suarez, Francisco and Nozariasbmarz, Amin and Vashaee, Daryoosh and Ozturk, Mehmet C.}, year={2016}, pages={2099–2113} }
@article{tayebi_tavakkoli yaraki_ahmadieh_tahriri_vashaee_tayebi_2016, title={Determination of total aflatoxin using cysteamine-capped CdS quantum dots as a fluorescence probe}, volume={294}, ISSN={0303-402X 1435-1536}, url={http://dx.doi.org/10.1007/s00396-016-3903-x}, DOI={10.1007/s00396-016-3903-x}, number={9}, journal={Colloid and Polymer Science}, publisher={Springer Nature}, author={Tayebi, Mahnoush and Tavakkoli Yaraki, Mohammad and Ahmadieh, Mahnaz and Tahriri, Mohammadreza and Vashaee, Daryoosh and Tayebi, Lobat}, year={2016}, month={Jun}, pages={1453–1462} }
@article{nozariasbmarz_zamanipour_norouzzadeh_krasinski_vashaee_2016, title={Enhanced thermoelectric performance in a metal/semiconductor nanocomposite of iron silicide/silicon germanium}, volume={6}, ISSN={2046-2069}, url={http://dx.doi.org/10.1039/C6RA01947A}, DOI={10.1039/c6ra01947a}, abstractNote={The metal–semiconductor nanocomposite of n-type thermoelectric SiGe–FeSi2 was successfully developed and characterized versus electrical, thermal, and microstructural properties.}, number={55}, journal={RSC Advances}, publisher={Royal Society of Chemistry (RSC)}, author={Nozariasbmarz, Amin and Zamanipour, Zahra and Norouzzadeh, Payam and Krasinski, Jerzy S. and Vashaee, Daryoosh}, year={2016}, pages={49643–49650} }
@article{norouzzadeh_vashaee_2016, title={Erratum to: The Effect of Multivalley Bandstructure on Thermoelectric Properties of Al x Ga1−x As}, volume={45}, ISSN={0361-5235 1543-186X}, url={http://dx.doi.org/10.1007/S11664-016-4439-Z}, DOI={10.1007/S11664-016-4439-Z}, number={6}, journal={Journal of Electronic Materials}, publisher={Springer Science and Business Media LLC}, author={Norouzzadeh, Payam and Vashaee, Daryoosh}, year={2016}, month={Mar}, pages={3249–3250} }
@article{karimi_rabiee_abdolrahim_tahriri_vashayee_tayebi_2016, title={High Sensitivity Electrochemical Multisensors based on Graphene-PANI Nanocomposite for Simultaneous Detection of Glucose and Urea}, volume={19}, ISSN={["1480-2422"]}, DOI={10.14447/jnmes.v19i3.311}, abstractNote={We present a study of the effect of graphene–PANI nanocomposites on the sensitivity of the urea and glucose multisensory. We used an electroctrochemical multisensor based on two electrodes located in a reservoir with two separate channels. The urease and glu-cose oxidase (GOD) were employed for detecting the urea and glucose, respectively. We characterized the graphene and graphene-PANI samples with X-ray Diffraction (XRD) analysis and scanning electron microscopy (SEM) observations. We further performed the Cyclic voltammetry and Amperometry tests. The collected experimental results revealed that the intensity of the peak significantly increases with the concentration of the urea and glucose.}, number={3}, journal={JOURNAL OF NEW MATERIALS FOR ELECTROCHEMICAL SYSTEMS}, author={Karimi, Meysam and Rabiee, Mohammad and Abdolrahim, Mojgan and Tahriri, Mohammadreza and Vashayee, Daryoosh and Tayebi, Lobat}, year={2016}, pages={145–150} }
@article{yazdimamaghani_razavi_vashaee_pothineni_assefa_köhler_rajadas_tayebi_2016, title={In vitro analysis of Mg scaffolds coated with polymer/hydrogel/ceramic composite layers}, volume={301}, ISSN={0257-8972}, url={http://dx.doi.org/10.1016/j.surfcoat.2016.01.017}, DOI={10.1016/j.surfcoat.2016.01.017}, abstractNote={Magnesium (Mg), as a biodegradable metal, has recently been considered to be used in hard tissue engineering scaffold design. However, the fast release of hydrogen gas during exposure of Mg to corroding biofluids significantly limits the cytocompatibility of the scaffolds. To overcome this key drawback, in this study, the surfaces of Mg scaffolds are modified by polymer/hydrogel/ceramic layers consisting of polycaprolactone (PCL), gelatin (Gel) and bioactive glass (BaG). A detailed study has been performed on the in vitro mechanical properties of the Mg scaffold coated by PCL–BaG/Gel–BaG compared with the uncoated one. Our results show that the coated scaffold can keep its mechanical integrity three times longer than the uncoated one. To assess cytocompatibility, human osteoblast Saos-2 cells were cultured on the surface of the scaffolds. Cell attachment and growth were evaluated by scanning electron microscopy and cell viability assays, respectively. While no cell could attach on the uncoated scaffold, cell viability and growth are acceptable on the Mg scaffold/PCL–BaG/Gel–BaG.}, journal={Surface and Coatings Technology}, publisher={Elsevier BV}, author={Yazdimamaghani, Mostafa and Razavi, Mehdi and Vashaee, Daryoosh and Pothineni, Venkata Raveendra and Assefa, Senait and Köhler, Gerwald A. and Rajadas, Jayakumar and Tayebi, Lobat}, year={2016}, month={Sep}, pages={126–132} }
@article{salahinejad_ghaffari_vashaee_tayebi_2016, title={Is cell viability always directly related to corrosion resistance of stainless steels?}, volume={62}, ISSN={0928-4931}, url={http://dx.doi.org/10.1016/j.msec.2016.01.091}, DOI={10.1016/j.msec.2016.01.091}, abstractNote={It has been frequently reported that cell viability on stainless steels is improved by increasing their corrosion resistance. The question that arises is whether human cell viability is always directly related to corrosion resistance in these biostable alloys. In this work, the microstructure and in vitro corrosion behavior of a new class of medical-grade stainless steels were correlated with adult human mesenchymal stem cell viability. The samples were produced by a powder metallurgy route, consisting of mechanical alloying and liquid-phase sintering with a sintering aid of a eutectic Mn-Si alloy at 1050 °C for 30 and 60 min, leading to nanostructures. In accordance with transmission electron microscopic studies, the additive particles for the sintering time of 30 min were not completely melted. Electrochemical impedance spectroscopic experiments suggested the higher corrosion resistance for the sample sintered for 60 min; however, a better cell viability on the surface of the less corrosion-resistant sample was unexpectedly found. This behavior is explained by considering the higher ion release rate of the Mn-Si additive material, as preferred sites to corrosion attack based on scanning electron microscopic observations, which is advantageous to the cells in vitro. In conclusion, cell viability is not always directly related to corrosion resistance in stainless steels. Typically, the introduction of biodegradable and biocompatible phases to biostable alloys, which are conventionally anticipated to be corrosion-resistant, can be advantageous to human cell responses similar to biodegradable metals.}, journal={Materials Science and Engineering: C}, publisher={Elsevier BV}, author={Salahinejad, E. and Ghaffari, M. and Vashaee, D. and Tayebi, L.}, year={2016}, month={May}, pages={439–443} }
@article{heidari_razavi_bahrololoom_bazargan-lari_vashaee_kotturi_tayebi_2016, title={Mechanical properties of natural chitosan/hydroxyapatite/magnetite nanocomposites for tissue engineering applications}, volume={65}, ISSN={["1873-0191"]}, DOI={10.1016/j.msec.2016.04.039}, abstractNote={Chitosan (CS), hydroxyapatite (HA), and magnetite (Fe3O4) have been broadly employed for bone treatment applications. Having a hybrid biomaterial composed of the aforementioned constituents not only accumulates the useful characteristics of each component, but also provides outstanding composite properties. In the present research, mechanical properties of pure CS, CS/HA, CS/HA/magnetite, and CS/magnetite were evaluated by the measurements of bending strength, elastic modulus, compressive strength and hardness values. Moreover, the morphology of the bending fracture surfaces were characterized using a scanning electron microscope (SEM) and an image analyzer. Studies were also conducted to examine the biological response of the human Mesenchymal Stem Cells (hMSCs) on different composites. We conclude that, although all of these composites possess in-vitro biocompatibility, adding hydroxyapatite and magnetite to the chitosan matrix can noticeably enhance the mechanical properties of the pure chitosan.}, journal={MATERIALS SCIENCE & ENGINEERING C-MATERIALS FOR BIOLOGICAL APPLICATIONS}, author={Heidari, Fatemeh and Razavi, Mehdi and Bahrololoom, Mohammad E. and Bazargan-Lari, Reza and Vashaee, Daryoosh and Kotturi, Hari and Tayebi, Lobat}, year={2016}, month={Aug}, pages={338–344} }
@inbook{razavi_salahinejad_fahmy_nowman_jazayeri_shah_vashaee_tayebi_tayebi_2016, title={Nanobiomaterials in periodontal tissue engineering}, ISBN={9780323428620}, url={http://dx.doi.org/10.1016/b978-0-323-42862-0.00011-0}, DOI={10.1016/b978-0-323-42862-0.00011-0}, abstractNote={Periodontitis is an inflammatory disease of the gums which spreads and affects the supporting tooth structures possibly leading to the loosening and loss of the tooth. Periodontal tissue engineering is considered a relatively new technique for the stimulation of the periodontal tissue formation using the basics of regenerative medicine. In this method, biodegradable porous scaffolds are employed as a temporary substitution of the injured or lost tissues to facilitate the regeneration process. Scaffolds are usually made of natural or synthetic polymers and ceramics doped with various nanobiomaterials for an intended functionalization. The addition of nanoparticles into the scaffold structure not only enhances the biomineralization potential of the composite scaffolds, but also improves their mechanical properties. Nanosized ceramic particles are of special importance as they mimic the mineral crystal structure of the natural tissues. They have been demonstrated to induce a considerable enhancement in the protein absorption and the cell adhesion compared to their micro-sized counterparts. This chapter reviews different nanobiomaterials employed in periodontal tissue engineering for the effective regeneration of lost tissues and discuss their benefits and drawbacks.}, booktitle={Nanobiomaterials in Hard Tissue Engineering}, publisher={Elsevier}, author={Razavi, Mehdi and Salahinejad, Erfan and Fahmy, Mina and Nowman, Aatif and Jazayeri, Hossein and Shah, Pinkesh and Vashaee, Daryoosh and Tayebi, Pouya and Tayebi, Lobat}, year={2016}, pages={323–351} }
@misc{ziabari_zebarjadi_vashaee_shakouri_2016, title={Nanoscale solid-state cooling: a review}, volume={79}, ISSN={["1361-6633"]}, DOI={10.1088/0034-4885/79/9/095901}, abstractNote={The recent developments in nanoscale solid-state cooling are reviewed. This includes both theoretical and experimental studies of different physical concepts, as well as nanostructured material design and device configurations. We primarily focus on thermoelectric, thermionic and thermo-magnetic coolers. Particular emphasis is given to the concepts based on metal-semiconductor superlattices, graded materials, non-equilibrium thermoelectric devices, Thomson coolers, and photon assisted Peltier coolers as promising methods for efficient solid-state cooling. Thermomagnetic effects such as magneto-Peltier and Nernst-Ettingshausen cooling are briefly described and recent advances and future trends in these areas are reviewed. The ongoing progress in solid-state cooling concepts such as spin-calorimetrics, electrocalorics, non-equilibrium/nonlinear Peltier devices, superconducting junctions and two-dimensional materials are also elucidated and practical achievements are reviewed. We explain the thermoreflectance thermal imaging microscopy and the transient Harman method as two unique techniques developed for characterization of thermoelectric microrefrigerators. The future prospects for solid-state cooling are briefly summarized.}, number={9}, journal={REPORTS ON PROGRESS IN PHYSICS}, author={Ziabari, Amirkoushyar and Zebarjadi, Mona and Vashaee, Daryoosh and Shakouri, Ali}, year={2016}, month={Sep} }
@article{rastegari_kani_salahinejad_fadavi_eftekhari_nozariasbmarz_tayebi_vashaee_2016, title={Non-hydrolytic sol-gel processing of chloride precursors loaded at forsterite stoichiometry}, volume={688}, ISSN={["1873-4669"]}, DOI={10.1016/j.jallcom.2016.07.187}, abstractNote={This paper for the first time investigates the sol-gel reaction of magnesium chloride and silicon tetrachloride, directed at the forsterite (Mg2SiO4) stoichiometry, using dry ethanol and glacial acetic acid as the solvent and chelating agent, respectively. The synthesized particles before and after calcination were characterized by transmission electron microscopy equipped with energy-dispersive X-ray spectroscopy mapping, X-ray diffraction and Fourier transform infrared spectroscopy. According to the results, the calcined nanoparticles showed a magnesia/forsterite structure along with silicon depletion, despite loading the forsterite stoichiometry. On the other hand, silicon-acetoxy bonds were detected in the xerogel (before calcination) as a result of the chelation reaction, albeit with a relatively uniform distribution of the essential elements. Since no non-alcoholyzed silicon-chlorine bond was detected in the xerogel, the development of the calcined structure was explained by the deficient sol-gel condensation and subsequent evaporation of silicon tetraacetate. It was inferred that the excessive amount of hydrogen chloride as the coproduct of the ethanolysis and chelation reactions of the precursors inhibits the condensation step, as confirmed by a supplementary test in an exaggerated circumstance. In conclusion, the silicon-containing species acts like a limiting reagent in the sol-gel condensation of forsterite using the chloride precursors and acetic acid chelator, in spite of loading the related stoichiometry.}, journal={JOURNAL OF ALLOYS AND COMPOUNDS}, author={Rastegari, S. and Kani, O. Seyed Mehdi and Salahinejad, E. and Fadavi, S. and Eftekhari, N. and Nozariasbmarz, A. and Tayebi, L. and Vashaee, D.}, year={2016}, month={Dec}, pages={235–241} }
@article{moharamzadehd_boccaccini_tayebi_2016, title={Porous magnesium-based scaffolds for tissue engineeng}, journal={Materials Science & Engineering. C, Biomimetic Materials, Sensors and Systems}, author={Moharamzadehd, K. and Boccaccini, A. R. and Tayebi, L.}, year={2016} }
@article{tayebi_tavakkoli yaraki_ahmadieh_mogharei_tahriri_vashaee_tayebi_2016, title={Synthesis, Surface Modification and Optical Properties of Thioglycolic Acid-Capped ZnS Quantum Dots for Starch Recognition at Ultralow Concentration}, volume={45}, ISSN={0361-5235 1543-186X}, url={http://dx.doi.org/10.1007/s11664-016-4792-y}, DOI={10.1007/s11664-016-4792-y}, number={11}, journal={Journal of Electronic Materials}, publisher={Springer Nature}, author={Tayebi, Mahnoush and Tavakkoli Yaraki, Mohammad and Ahmadieh, Mahnaz and Mogharei, Azadeh and Tahriri, Mohammadreza and Vashaee, Daryoosh and Tayebi, Lobat}, year={2016}, month={Aug}, pages={5671–5678} }
@article{tayebi_tavakkoli yaraki_mogharei_ahmadieh_tahriri_vashaee_tayebi_2016, title={Thioglycolic Acid-Capped CdS Quantum Dots Conjugated to α-Amylase as a Fluorescence Probe for Determination of Starch at Low Concentration}, volume={26}, ISSN={1053-0509 1573-4994}, url={http://dx.doi.org/10.1007/s10895-016-1870-8}, DOI={10.1007/s10895-016-1870-8}, number={5}, journal={Journal of Fluorescence}, publisher={Springer Nature}, author={Tayebi, Mahnoush and Tavakkoli Yaraki, Mohammad and Mogharei, Azadeh and Ahmadieh, Mahnaz and Tahriri, Mohammadreza and Vashaee, Daryoosh and Tayebi, Lobat}, year={2016}, month={Jul}, pages={1787–1794} }
@article{hyland_hunter_liu_veety_vashaee_2016, title={Wearable thermoelectric generators for human body heat harvesting}, volume={182}, ISSN={["1872-9118"]}, DOI={10.1016/j.apenergy.2016.08.150}, abstractNote={A thermoelectric generator (TEG) can be used to harvest electrical energy from human body heat for the purpose of powering wearable electronics. At the NSF Advanced Self-Powered Systems of Integrated Sensors and Technologies (ASSIST), TEGs are one of the enabling technologies being explored to advance the center’s mission of creating wearable, self-powered, health and environmental monitoring systems. As part of this effort, an exploration of the relevant parameters for maximizing the wearable TEG power output from the body heat and maintaining the body comfort is particularly important. For this purpose, the heat from the body must be directed into TEG with minimal loss, the generator must be designed for maintaining a high temperature differential across the thermoelectric material, and the generator must have a small form factor to maintain the body comfort. In order to address these requirements, an optimum TEG design was developed and experiments were conducted both on a temperature-controlled hot plate and on different body locations including the wrist, upper arm, and chest. The TEG was further fabricated into a T-shirt and the power was recorded for different human activities. Comparison of the experiments on various body locations and on the T-shirt yielded the highest to lowest power generated on the upper arm, wrist, chest and T-shirt, respectively. The prospect of powering a wearable electrocardiogram sensor by a TEG on the upper arm is discussed.}, journal={APPLIED ENERGY}, author={Hyland, Melissa and Hunter, Haywood and Liu, Jie and Veety, Elena and Vashaee, Daryoosh}, year={2016}, month={Nov}, pages={518–524} }
@article{yazdimamaghani_razavi_mozafari_vashaee_kotturi_tayebi_2015, title={Biomineralization and biocompatibility studies of bone conductive scaffolds containing poly(3,4-ethylenedioxythiophene): poly(4-styrene sulfonate) (PEDOT:PSS)}, volume={26}, ISSN={["1573-4838"]}, DOI={10.1007/s10856-015-5599-8}, number={12}, journal={JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE}, author={Yazdimamaghani, Mostafa and Razavi, Mehdi and Mozafari, Masoud and Vashaee, Daryoosh and Kotturi, Hari and Tayebi, Lobat}, year={2015}, month={Dec} }
@article{abudakka_nozariasbmarz_tayebi_krasisnki_vashaee_2015, title={Development of Inexpensive SiGe–FeSi2 Thermoelectric Nanocomposites}, volume={2}, ISSN={2329-8774 2329-8766}, url={http://dx.doi.org/10.1515/ehs-2014-0039}, DOI={10.1515/ehs-2014-0039}, abstractNote={Abstract This investigation presents cost-effective fabrication of n-type silicon germanium–iron disilicide nanocomposites using low-cost low-purity germanium–germanium oxide powder. Moreover, the probability of the reduction of oxide powders during the synthesis process was studied. X-ray diffraction (XRD) analysis indicated reduction of germanium oxide impurity in the synthesized material. Scanning electron microscopy (SEM) along with the energy-dispersive spectrometer (EDS) showed a structure of dispersed iron disilicide particles embedded in silicon germanium matrix. The nanocomposite structure showed a moderate figure-of-merit, ZT, equal to 0.8. The ZT enhancement was related to both the nanocomposite structure and the reduction of germanium oxide.}, number={1-2}, journal={Energy Harvesting and Systems}, publisher={Walter de Gruyter GmbH}, author={Abudakka, Mohamed and Nozariasbmarz, Amin and Tayebi, Lobat and Krasisnki, Jerzy S. and Vashaee, Daryoosh}, year={2015}, month={Jan} }
@article{rabiee_nazparvar_azizian_vashaee_tayebi_2015, title={Effect of ion substitution on properties of bioactive glasses: A review}, volume={41}, ISSN={0272-8842}, url={http://dx.doi.org/10.1016/j.ceramint.2015.02.140}, DOI={10.1016/j.ceramint.2015.02.140}, abstractNote={Bioactive glasses and glass-ceramics have recently found key applications in biomedicine, mainly for bone repair and replacement. Recent developments in the field of tissue engineering have re-invigorated the quest to enhance the physical and biomedical effectiveness of bioactive glasses and glass-ceramics by incorporation of different elements into the composition of these materials. Although most elements are included in the bioactive glass for the therapeutic benefits (e.g., Ag and Sr), they influence the structure and bioactivity of the glass. This review systematically discusses the influence of the addition of silver (Ag), magnesium (Mg), strontium (Sr), zinc (Zn), aluminum (Al), potassium (P), fluoride (F) and zirconia (ZrO2) elements on the chemical, physical and therapeutic properties of bioactive glasses and glass-ceramics, which are expected to play an important role in the future of bone regenerative medicine. This article describes where these dopant ions fit into the glass structure and how these affect the delivery and properties of the glass as a whole.}, number={6}, journal={Ceramics International}, publisher={Elsevier BV}, author={Rabiee, Sayed Mahmood and Nazparvar, Neda and Azizian, Misaq and Vashaee, Daryoosh and Tayebi, Lobat}, year={2015}, month={Jul}, pages={7241–7251} }
@inbook{amrollahi_krasinski_vaidyanathan_tayebi_vashaee_2015, title={Electrophoretic Deposition (EPD): Fundamentals and Applications from Nano- to Microscale Structures}, ISBN={9783319152653 9783319152660}, url={http://dx.doi.org/10.1007/978-3-319-15266-0_7}, DOI={10.1007/978-3-319-15266-0_7}, booktitle={Handbook of Nanoelectrochemistry}, publisher={Springer International Publishing}, author={Amrollahi, Pouya and Krasinski, Jerzy S. and Vaidyanathan, Ranji and Tayebi, Lobat and Vashaee, Daryoosh}, year={2015}, month={Sep}, pages={561–591} }
@article{misra_bozkurt_calhoun_jackson_jur_lach_lee_muth_oralkan_oeztuerk_et al._2015, title={Flexible Technologies for Self-Powered Wearable Health and Environmental Sensing}, volume={103}, ISSN={["1558-2256"]}, DOI={10.1109/jproc.2015.2412493}, abstractNote={This article provides the latest advances from the NSF Advanced Self-powered Systems of Integrated sensors and Technologies (ASSIST) center. The work in the center addresses the key challenges in wearable health and environmental systems by exploring technologies that enable ultra-long battery lifetime, user comfort and wearability, robust medically validated sensor data with value added from multimodal sensing, and access to open architecture data streams. The vison of the ASSIST center is to use nanotechnology to build miniature, self-powered, wearable, and wireless sensing devices that can enable monitoring of personal health and personal environmental exposure and enable correlation of multimodal sensors. These devices can empower patients and doctors to transition from managing illness to managing wellness and create a paradigm shift in improving healthcare outcomes. This article presents the latest advances in high-efficiency nanostructured energy harvesters and storage capacitors, new sensing modalities that consume less power, low power computation, and communication strategies, and novel flexible materials that provide form, function, and comfort. These technologies span a spatial scale ranging from underlying materials at the nanoscale to body worn structures, and the challenge is to integrate them into a unified device designed to revolutionize wearable health applications.}, number={4}, journal={PROCEEDINGS OF THE IEEE}, author={Misra, Veena and Bozkurt, Alper and Calhoun, Benton and Jackson, Thomas N. and Jur, Jesse S. and Lach, John and Lee, Bongmook and Muth, John and Oralkan, Oemer and Oeztuerk, Mehmet and et al.}, year={2015}, month={Apr}, pages={665–681} }
@inbook{razavi_salahinejad_fahmy_yazdimamaghani_vashaee_tayebi_2015, title={Green Chemical and Biological Synthesis of Nanoparticles and Their Biomedical Applications}, ISBN={9783319154602 9783319154619}, url={http://dx.doi.org/10.1007/978-3-319-15461-9_7}, DOI={10.1007/978-3-319-15461-9_7}, booktitle={Green Processes for Nanotechnology}, publisher={Springer International Publishing}, author={Razavi, Mehdi and Salahinejad, Erfan and Fahmy, Mina and Yazdimamaghani, Mostafa and Vashaee, Daryoosh and Tayebi, Lobat}, year={2015}, pages={207–235} }
@article{razavi_fathi_savabi_vashaee_tayebi_2015, title={In Vitro Analysis of Electrophoretic Deposited Fluoridated Hydroxyapatite Coating on Micro-arc Oxidized AZ91 Magnesium Alloy for Biomaterials Applications}, volume={46A}, ISSN={["1543-1940"]}, DOI={10.1007/s11661-014-2694-2}, number={3}, journal={METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE}, author={Razavi, Mehdi and Fathi, Mohammadhossein and Savabi, Omid and Vashaee, Daryoosh and Tayebi, Lobat}, year={2015}, month={Mar}, pages={1394–1404} }
@article{heidari_bahrololoom_vashaee_tayebi_2015, title={In situ preparation of iron oxide nanoparticles in natural hydroxyapatite/chitosan matrix for bone tissue engineering application}, volume={41}, ISSN={["1873-3956"]}, DOI={10.1016/j.ceramint.2014.10.153}, abstractNote={Magnetic materials inside bone scaffolds are known to be a promoting factor for bone healing especially when the therapy is accompanied by application of external magnetic stimulation. In this study we employed a new route to synthesize iron oxide nanoparticles inside hydroxyapatite/chitosan bone scaffolds. Hydroxyapatite and chitosan are both natural compounds and were prepared from bovine cortical bone and shrimp shell, respectively. The morphology and composition of the synthesized materials were characterized employing scanning electron microscopy and FTIR spectroscopy. The iron oxide mean particle size inside the scaffold matrix was estimated to be in the range of 10–40 nm by particle size analyzer and transmission electron microscopy. The X-ray powder diffraction pattern indicated that the magnetite crystal size was about 23.5 nm. Magnetic measurements specified that the saturated magnetic intensity (Ms) was approximately 3.04 emu/g and the coercive force was 128.39 Oe. The results revealed that the as-prepared magnetite was super-paramagnetic.}, number={2}, journal={CERAMICS INTERNATIONAL}, author={Heidari, Fatemeh and Bahrololoom, Mohammad E. and Vashaee, Daryoosh and Tayebi, Lobat}, year={2015}, month={Mar}, pages={3094–3100} }
@article{razavi_fathi_savabi_vashaee_tayebi_2015, title={In vivo assessments of bioabsorbable AZ91 magnesium implants coated with nanostructured fluoridated hydroxyapatite by MAO/EPD technique for biomedical applications}, volume={48}, ISSN={0928-4931}, url={http://dx.doi.org/10.1016/j.msec.2014.11.020}, DOI={10.1016/j.msec.2014.11.020}, abstractNote={Although magnesium (Mg) is a unique biodegradable metal which possesses mechanical property similar to that of the natural bone and can be an attractive material to be used as orthopedic implants, its quick corrosion rate restricts its actual clinical applications. To control its rapid degradation, we have modified the surface of magnesium implant using fluoridated hydroxyapatite (FHA: Ca10(PO4)6OH2-xFx) through the combined micro-arc oxidation (MAO) and electrophoretic deposition (EPD) techniques, which was presented in our previous paper. In this article, the biocompatibility examinations were conducted on the coated AZ91 magnesium alloy by implanting it into the greater trochanter area of rabbits. The results of the in vivo animal test revealed a significant enhancement in the biocompatibility of FHA/MAO coated implant compared to the uncoated one. By applying the FHA/MAO coating on the AZ91 implant, the amount of weight loss and magnesium ion release in blood plasma decreased. According to the histological results, the formation of the new bone increased and the inflammation decreased around the implant. In addition, the implantation of the uncoated AZ91 alloy accompanied by the release of hydrogen gas around the implant; this release was suppressed by applying the coated implant. Our study exemplifies that the surface coating of magnesium implant using a bioactive ceramic such as fluoridated hydroxyapatite may improve the biocompatibility of the implant to make it suitable as a commercialized biomedical product.}, journal={Materials Science and Engineering: C}, publisher={Elsevier BV}, author={Razavi, Mehdi and Fathi, Mohammadhossein and Savabi, Omid and Vashaee, Daryoosh and Tayebi, Lobat}, year={2015}, month={Mar}, pages={21–27} }
@article{razavi_fathi_savabi_vashaee_tayebi_2015, title={In vivo biocompatibility of Mg implants surface modified by nanostructured merwinite/PEO}, volume={26}, ISSN={0957-4530 1573-4838}, url={http://dx.doi.org/10.1007/s10856-015-5514-3}, DOI={10.1007/s10856-015-5514-3}, number={5}, journal={Journal of Materials Science: Materials in Medicine}, publisher={Springer Science and Business Media LLC}, author={Razavi, Mehdi and Fathi, Mohammadhossein and Savabi, Omid and Vashaee, Daryoosh and Tayebi, Lobat}, year={2015}, month={Apr} }
@article{bahramian_vashaee_2015, title={In-situ fabricated transparent conducting nanofiber-shape polyaniline/coral-like TiO2 thin film: Application in bifacial dye-sensitized solar cells}, volume={143}, ISSN={["1879-3398"]}, DOI={10.1016/j.solmat.2015.07.011}, abstractNote={Dye-sensitized solar cell (DSSC) is the most promising of third generation solar cells for large scale applications due its low cost, flexibility, and scalable manufacturability. However, enhancing the efficiency of the DSSC is still highly desired. In this study, we designed a novel bifacial DSSC based on a transparent Polyaniline (PANI) films as counter electrode (CE) associated with coral-like TiO2 nanostructured films, which can be used as the photoanode. PANI-based CEs were prepared by a facile in situ polymerization, while coral-like TiO2 films were chemically synthesized at low temperature through the sol–gel process. Owing to the light irradiation from both the front and the rear sides, it is expected that higher density of dye molecules should be excited. In addition, due to the excellent light scattering of the coal-like TiO2 and high specific surface area of PANI nanofibers (NFs), more carriers are generated. Both these factors resulted in the increase of the conversion efficiency. The bifacial DSSC fabricated by combining the PANI NFs-based film and the coral-like TiO2 film in the presence of the expensive N719 dye molecules showed the efficiency of 8.22% corresponding to the both-side irradiation. In comparison, similar cells employing either a cross-linked PANI- or Pt-based CE showed efficiencies of 7.81% and 7.75%, respectively. The results of the similar cells in the presence of the low cost CoPC dye molecules showed efficiencies of 0.29%, 0.22%, and 0.27%, for DSSCs comprised of PANI NFs-, cross-linked PANI-, and Pt-based CEs, respectively. The low fabrication cost as well as the improved light absorption highlights the potential application of the coral-like TiO2 and PANI NFs-based films in fabrication of bifacial DSSCs.}, journal={SOLAR ENERGY MATERIALS AND SOLAR CELLS}, author={Bahramian, Alireza and Vashaee, Daryoosh}, year={2015}, month={Dec}, pages={284–295} }
@article{razavi_fathi_savabi_vashaee_tayebi_2015, title={Regenerative influence of nanostructured bredigite (Ca7MgSi4O16)/anodic spark coating on biodegradable AZ91 magnesium alloy implants for bone healing}, volume={155}, ISSN={0167-577X}, url={http://dx.doi.org/10.1016/j.matlet.2015.04.129}, DOI={10.1016/j.matlet.2015.04.129}, abstractNote={Magnesium has been recently introduced as a novel biodegradable material for bone healing. However, the fast degradation of this material results in the fast release of hydrogen which limits its clinical applications. In view of that, in the present study, we attempt to overcome this drawback using a bredigite (Ca7MgSi4O16) coating. In our previous work, we have coated AZ91 magnesium implants with bredigite through the combination of anodic spark deposition (ASD) and electrophoretic deposition (EPD) techniques. As continuation to that work, in this paper, we have focused on the in vivo examination of the bredigite/ASD compared to the plain ASD coated and the uncoated AZ91 substrates. The results of the in vivo animal test in the greater trochanter of rabbits indicated improved regeneration of bone and less bone inflammation upon employing bredigite/ASD coated implants. In addition, an enhancement in in vivo biodegradation was observed by the reduction in magnesium ion released in the blood plasma. In summary, a surface treatment using bredigite on magnesium implants promotes their bone healing capabilities for future clinical applications.}, journal={Materials Letters}, publisher={Elsevier BV}, author={Razavi, Mehdi and Fathi, Mohammadhossein and Savabi, Omid and Vashaee, Daryoosh and Tayebi, Lobat}, year={2015}, month={Sep}, pages={97–101} }
@article{yazdimamaghani_razavi_vashaee_pothineni_rajadas_tayebi_2015, title={Significant degradability enhancement in multilayer coating of polycaprolactone-bioactive glass/gelatin-bioactive glass on magnesium scaffold for tissue engineering applications}, volume={338}, ISSN={0169-4332}, url={http://dx.doi.org/10.1016/j.apsusc.2015.02.120}, DOI={10.1016/j.apsusc.2015.02.120}, abstractNote={Magnesium (Mg) is a promising candidate to be used in medical products especially as bone tissue engineering scaffolds. The main challenge for using Mg in biomedical applications is its high degradation rate in the body. For this reason, in this study, a multilayer polymeric layer composed of polycaprolactone (PCL) and gelatin (Gel) reinforced with bioactive glass (BaG) particles has been applied on the surface of Mg scaffolds. The materials characteristics of uncoated Mg scaffold, Mg scaffold coated only with PCL-BaG and Mg scaffold coated with PCL-BaG and Gel-BaG have been analyzed and compared in detail. Scanning electron microscope (SEM) equipped with energy dispersive spectroscopy (EDS), and Fourier transform infrared spectroscopy (FTIR) were utilized for microstructural studies. In vitro bioactivity and biodegradation evaluations were carried out by submerging the scaffolds in simulated body fluid (SBF) at pre-determined time points. The results demonstrated that Mg scaffold coated with PCL-BaG and Gel-BaG exhibited significant improvement in biodegradability.}, journal={Applied Surface Science}, publisher={Elsevier BV}, author={Yazdimamaghani, Mostafa and Razavi, Mehdi and Vashaee, Daryoosh and Pothineni, Venkata Raveendra and Rajadas, Jayakumar and Tayebi, Lobat}, year={2015}, month={May}, pages={137–145} }
@article{yazdimamaghani_razavi_vashaee_tayebi_2015, title={Surface modification of biodegradable porous Mg bone scaffold using polycaprolactone/bioactive glass composite}, volume={49}, ISSN={0928-4931}, url={http://dx.doi.org/10.1016/j.msec.2015.01.041}, DOI={10.1016/j.msec.2015.01.041}, abstractNote={A reduction in the degradation rate of magnesium (Mg) and its alloys is in high demand to enable these materials to be used in orthopedic applications. For this purpose, in this paper, a biocompatible polymeric layer reinforced with a bioactive ceramic made of polycaprolactone (PCL) and bioactive glass (BG) was applied on the surface of Mg scaffolds using dip-coating technique under low vacuum. The results indicated that the PCL-BG coated Mg scaffolds exhibited noticeably enhanced bioactivity compared to the uncoated scaffold. Moreover, the mechanical integrity of the Mg scaffolds was improved using the PCL-BG coating on the surface. The stable barrier property of the coatings effectively delayed the degradation activity of Mg scaffold substrates. Moreover, the coatings induced the formation of apatite layer on their surface after immersion in the SBF, which can enhance the biological bone in-growth and block the microcracks and pore channels in the coatings, thus prolonging their protective effect. Furthermore, it was shown that a three times increase in the concentration of PCL-BG noticeably improved the characteristics of scaffolds including their degradation resistance and mechanical stability. Since bioactivity, degradation resistance and mechanical integrity of a bone substitute are the key factors for repairing and healing fractured bones, we suggest that PCL-BG is a suitable coating material for surface modification of Mg scaffolds.}, journal={Materials Science and Engineering: C}, publisher={Elsevier BV}, author={Yazdimamaghani, Mostafa and Razavi, Mehdi and Vashaee, Daryoosh and Tayebi, Lobat}, year={2015}, month={Apr}, pages={436–444} }
@article{norouzzadeh_vashaee_2015, title={The Effect of Multivalley Bandstructure on Thermoelectric Properties of Al (x) Ga1-x As}, volume={44}, ISSN={["1543-186X"]}, DOI={10.1007/s11664-014-3535-1}, number={2}, journal={JOURNAL OF ELECTRONIC MATERIALS}, author={Norouzzadeh, Payam and Vashaee, Daryoosh}, year={2015}, month={Feb}, pages={636–644} }
@article{norouzzadeh_nozariasbmarz_krasinski_vashaee_2015, title={Thermal conductivity of nanostructured SixGe1-x in amorphous limit by molecular dynamics simulation}, volume={117}, ISSN={["1089-7550"]}, DOI={10.1063/1.4921536}, abstractNote={We report the thermal conductivity of amorphous SixGe1−x compound calculated versus composition and temperature. The result sets the minimum value of thermal conductivity which is achievable by nanostructuring. We employed molecular dynamics with Tersoff's potential for the calculations. It was found that, contrary to the crystalline SixGe1−x, the thermal conductivity of amorphous phase is a weak function of the material composition. For the most popular composition Si0.8Ge0.2, the thermal conductivity of the amorphous phase is less than 1 W m−1 K−1 with small reduction as the temperature increases from 300 K to 1400 K. The thermal conductivity of amorphous SixGe1−x for any value of x is approximately an order of magnitude smaller than the minimum thermal conductivity of crystalline SixGe1−x alloy, which occurs near x = 0.5. It is known that alloying with germanium is more efficient than nanostructuring to reduce the thermal conductivity of silicon; however, it was found that the amorphization process is even more effective than alloying for that purpose. It was also shown that the reduction of the thermal conductivity of silicon due to alloying with germanium is more efficient in crystalline phase than in amorphous phase.}, number={21}, journal={JOURNAL OF APPLIED PHYSICS}, author={Norouzzadeh, Payam and Nozariasbmarz, Amin and Krasinski, Jerzy S. and Vashaee, Daryoosh}, year={2015}, month={Jun} }
@article{mohebali_liu_tayebi_krasinski_vashaee_2015, title={Thermoelectric figure of merit of bulk FeSi2-Si0.8Ge0.2 nanocomposite and a comparison with beta-FeSi2}, volume={74}, ISSN={["0960-1481"]}, DOI={10.1016/j.renene.2014.08.059}, abstractNote={Among various thermoelectric (TE) materials, iron disilicide (FeSi2) has relatively low cost and non-toxic characteristics which make it appropriate for large scale applications. To enhance the dimensionless figure of merit (ZT) of this material, a composite of FeSi2–Si0.8Ge0.2 with high fraction of α-FeSi2 was prepared by mechanical alloying and sintering. The process was followed by thermal annealing to transform α to β phase FeSi2 through a slow peritectoid reaction (several hours). The thermoelectric properties were significantly improved upon the completion of the phase transformation. At temperatures above 900 °C, FeSi2 component rapidly changed from β to α phase (several minutes) leading to sudden increase of the thermal conductivity. For comparison, the thermoelectric alloy of β-FeSi2 was prepared through a similar process. The effect of sintering conditions and annealing time were studied and a comparison was drawn between the thermoelectric properties of β-FeSi2 and FeSi2–Si0.8Ge0.2 nanocomposite. Overall, (FeSi2)0.75(Si0.8Ge0.2)0.25 showed 170% enhancement in ZT compared with β-FeSi2 making it suitable for medium to high temperature applications (500 °C −850 °C).}, journal={RENEWABLE ENERGY}, author={Mohebali, Milad and Liu, Yin and Tayebi, Lobat and Krasinski, Jerzy S. and Vashaee, Daryoosh}, year={2015}, month={Feb}, pages={940–947} }
@article{norouzzadeh_krasinski_myles_vashaee_2015, title={Type VIII Si based clathrates: prospects for a giant thermoelectric power factor}, volume={17}, ISSN={["1463-9084"]}, DOI={10.1039/c5cp00729a}, abstractNote={Although clathrate materials are known for their small thermal conductivity, they have not shown a large thermoelectric power factor so far. We present the band structures of type VIII Si, Ge, and Sn clathrates as well as the alkali and alkaline-earth intercalated type VIII Si clathrates. Our calculations revealed that this group of materials has potentially large power factors due to the existence of a large number of carrier pockets near their band edges. In particular, we calculated the charge carrier transport properties of Si46-VIII both for n-type and p-type materials. The exceptionally high multi-valley band structure of Si46-VIII near the Fermi energy due to the high crystallographic symmetry resulted in a giant power factor in this material. It was shown that the intercalation of Si46-VIII with alkali and alkaline-earth guest atoms shifts the Fermi energy close to the conduction band edge and, except for Be8Si46 and Mg8Si46, they weakly influence the band structure of Si46. Among these clathrate systems, Ca8Si46, Sr8Si46, and Ba8Si46 showed negative formation energy, which should facilitate their synthesis. Our results imply that the intercalation affects the conduction band of Si46-VIII more than its valence band. Also, interestingly, the type VIII clathrates of Si46 and its derivatives (except Be8Si46 and Mg8Si46), Sn46, and Ge46 all have 26 carrier pockets near their valence band edge. Among the different derivatives of Si46-VIII, Rb8Si46 and Ba8Si46 have the highest number of electron pockets near their band edges. The thermoelectric power factor was predicted using a multiband Boltzmann transport equation linked with parameters extracted from density functional calculations. It was shown that both the increment of charge mobility and the existence of multiple band extrema contribute to the enhancement of the thermoelectric power factor considerably. Such a large power factor along with their inherently low thermal conductivity can make this group of clathrates promising thermoelectric materials.}, number={14}, journal={PHYSICAL CHEMISTRY CHEMICAL PHYSICS}, author={Norouzzadeh, Payam and Krasinski, Jerzy S. and Myles, Charles W. and Vashaee, Daryoosh}, year={2015}, pages={8850–8859} }
@article{razavi_fathi_savabi_vashaee_tayebi_2014, title={Biodegradable magnesium alloy coated by fluoridated hydroxyapatite using MAO/EPD technique}, volume={30}, ISSN={0267-0844 1743-2944}, url={http://dx.doi.org/10.1179/1743294414Y.0000000284}, DOI={10.1179/1743294414Y.0000000284}, abstractNote={In this paper, a nanostructured fluoridated hydroxyapatite (FHA) coating was used on AZ91 magnesium to improve its corrosion resistance and in vitro bioactivity. The coating was made through micro arc oxidation (MAO) and electrophoretic deposition (EPD) method. After characterising phase composition and surface morphology, the corrosion and the in vitro bioactivity behaviours of the coated materials were investigated by electrochemical measurements and immersion tests in simulated body fluid (SBF). The results confirmed the enhancement of the corrosion resistance and the bioactivity of the AZ91 alloy coated with nanostructured FHA. Therefore, the surface treatment introduced in this paper may be an apt approach to make magnesium alloys more suitable for orthopedic applications.}, number={8}, journal={Surface Engineering}, publisher={Informa UK Limited}, author={Razavi, M. and Fathi, M. and Savabi, O. and Vashaee, D. and Tayebi, L.}, year={2014}, month={May}, pages={545–551} }
@article{razavi_fathi_savabi_vashaee_tayebi_2014, title={Biodegradation, Bioactivity and In vivo Biocompatibility Analysis of Plasma Electrolytic Oxidized (PEO) Biodegradable Mg Implants}, volume={4}, ISSN={2348-0130}, url={http://dx.doi.org/10.9734/psij/2014/9265}, DOI={10.9734/psij/2014/9265}, abstractNote={In this paper, a plasma electrolytic oxidation (PEO) coating was prepared on AZ91 magnesium (Mg) implant to improve its degradation resistance, bioactivity and biocompatibility. The phase composition and surface morphology of the samples were characterizedusing X-ray diffraction (XRD) and scanning electron microscope (SEM). The corrosion rate and the bioactivity behavior of the samples were investigated via electrochemical measurements and immersion tests in simulated body fluid (SBF). The Original ResearchArticle}, number={5}, journal={Physical Science International Journal}, publisher={SCIENCEDOMAIN international}, author={Razavi, Mehdi and Fathi, Mohammad Hossein and Savabi, Omid and Vashaee, Daryoosh and Tayebi, Lobat}, editor={Brosseau, ChristianEditor}, year={2014}, month={Jan}, pages={708–722} }
@inbook{mozafari_shabafrooz_yazdimamaghani_vashaee_tayebi_2014, title={Chapter 5: Nanofibrous Scaffolds for Tissue Engineering Applications: State-of-the-Art and Future Trends}, ISBN={9789814494830 9789814494847}, ISSN={2251-3965}, url={http://dx.doi.org/10.1142/9789814494847_0005}, DOI={10.1142/9789814494847_0005}, booktitle={Tissue Regeneration}, publisher={WORLD SCIENTIFIC}, author={Mozafari, Masoud and Shabafrooz, Vahid and Yazdimamaghani, Mostafa and Vashaee, Daryoosh and Tayebi, Lobat}, year={2014}, month={Jan}, pages={163–203} }
@article{razavi_fathi_savabi_beni_razavi_vashaee_tayebi_2014, title={Coating of biodegradable magnesium alloy bone implants using nanostructured diopside (CaMgSi2O6)}, volume={288}, ISSN={0169-4332}, url={http://dx.doi.org/10.1016/j.apsusc.2013.09.160}, DOI={10.1016/j.apsusc.2013.09.160}, abstractNote={Magnesium alloys with their biodegradable characteristic can be a very good candidate to be used in orthopedic implants. However, magnesium alloys may corrode and degrade too fast for applications in the bone healing procedure. In order to enhance the corrosion resistance and the in vitro bioactivity of a magnesium alloy, a nanostructured diopside (CaMgSi2O6) film was coated on AZ91 magnesium alloy through combined micro-arc oxidation (MAO) and electrophoretic deposition (EPD) methods. The crystalline structures, morphologies and compositions of the coated and uncoated substrates were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy. Polarization, electrochemical impedance spectroscopy, and immersion test in simulated body fluid (SBF) were employed to evaluate the corrosion resistance and the in vitro bioactivity of the samples. The results of our investigation showed that the nanostructured diopside coating deposited on the MAO layer increases the corrosion resistance and improves the in vitro bioactivity of the biodegradable magnesium alloy.}, journal={Applied Surface Science}, publisher={Elsevier BV}, author={Razavi, Mehdi and Fathi, Mohammadhossein and Savabi, Omid and Beni, Batoul Hashemi and Razavi, Seyed Mohammad and Vashaee, Daryoosh and Tayebi, Lobat}, year={2014}, month={Jan}, pages={130–137} }
@article{tahmasbi rad_ali_kotturi_yazdimamaghani_smay_vashaee_tayebi_2014, title={Conducting scaffolds for liver tissue engineering}, volume={102}, ISSN={1549-3296}, url={http://dx.doi.org/10.1002/jbm.a.35080}, DOI={10.1002/jbm.a.35080}, abstractNote={It is known that there is a correlation between a cell membrane potential and the proliferation of the cell. The high proliferation capacity of liver cells can also be attributed to its specific cell membrane potential as liver cell is recognized as one of the most depolarized of all differentiated cells. We hypothesized that this phenomenon can be emphasized by growing liver cells in conducting scaffolds that can increase the electrical communication among the cells. In this article, using tissue engineering techniques, we grew hepatocyte cells in scaffolds with various compositions. It was found that the scaffolds containing conducting polymer of poly (3,4-ethylenedioxythiophene) (PEDOT) provide the best condition for attachment and proliferation of the cells. More specifically, the blend of hyaluronan, PEDOT, and collagen (I) as dopants in gelatin–chitosan-based scaffold presented the best cell/scaffold interactions for regeneration of liver cells. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 4169–4181, 2014.}, number={11}, journal={Journal of Biomedical Materials Research Part A}, publisher={Wiley}, author={Tahmasbi Rad, Armin and Ali, Naushad and Kotturi, Hari Shankar R. and Yazdimamaghani, Mostafa and Smay, Jim and Vashaee, Daryoosh and Tayebi, Lobat}, year={2014}, month={Feb}, pages={4169–4181} }
@article{razavi_fathi_savabi_mohammad razavi_hashemi beni_vashaee_tayebi_2014, title={Controlling the degradation rate of bioactive magnesium implants by electrophoretic deposition of akermanite coating}, volume={40}, ISSN={0272-8842}, url={http://dx.doi.org/10.1016/j.ceramint.2013.08.027}, DOI={10.1016/j.ceramint.2013.08.027}, abstractNote={In order to improve the corrosion resistance and the surface bioactivity of biodegradable magnesium alloys, a nanostructured akermanite (Ca2MgSi2O7) coating was grown on AZ91 magnesium alloy through electrophoretic deposition (EPD) assisted with micro arc oxidation (MAO) method. The crystalline structures, morphologies and compositions of samples were characterized by X–ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. The in vitro bio–corrosion (biodegradability) and bioactivity behaviors of samples were investigated by electrochemical and immersion tests. The experimental results indicated that the nanostructured akermanite coating could slow down the corrosion rate and improve the in vitro bioactivity of biodegradable magnesium alloy. Thus, magnesium alloy coated with nanostructured akermanite may be a promising candidate to be used as biodegradable bone implants.}, number={3}, journal={Ceramics International}, publisher={Elsevier BV}, author={Razavi, Mehdi and Fathi, Mohammadhossein and Savabi, Omid and Mohammad Razavi, Seyed and Hashemi Beni, Batoul and Vashaee, Daryoosh and Tayebi, Lobat}, year={2014}, month={Apr}, pages={3865–3872} }
@article{tayebi_zamanipour_vashaee_2014, title={Design optimization of micro-fabricated thermoelectric devices for solar power generation}, volume={69}, ISSN={0960-1481}, url={http://dx.doi.org/10.1016/j.renene.2014.02.055}, DOI={10.1016/j.renene.2014.02.055}, abstractNote={Solar thermoelectric power generation is known as an economic way to utilize the full solar spectrum energy with less dependency on daylight and weather conditions. Despite recent advances in the development of efficient thin film thermoelectric materials, micro-fabrication techniques for batch processing of solar thermoelectric power generators have not yet been pursued. This is mainly associated with the efficiency loss and low fabrication yield resulting from the small thickness of the thermoelectric layers. To address these issues, a planar thin film solar thermoelectric generator has been designed and optimized for micro-fabrication processing. This planar design possesses two attractive benefits. First, the length of the thermoelectric element can be flexibly optimized since it is not the same as the thickness of the deposited film. Second, deposition and patterning of both n- and p-type thermoelectric layers can be easily done using conventional micro-fabrication techniques. The application of thin film infrared reflecting coatings to enhance the efficiency was further considered. Theoretical analysis shows that the efficiency of this micro-machined solar thermoelectric device is comparable with the conventional solar cells while providing a less interruptive source of energy.}, journal={Renewable Energy}, publisher={Elsevier BV}, author={Tayebi, Lobat and Zamanipour, Zahra and Vashaee, Daryoosh}, year={2014}, month={Sep}, pages={166–173} }
@article{yazdimamaghani_razavi_vashaee_tayebi_2014, title={Development and degradation behavior of magnesium scaffolds coated with polycaprolactone for bone tissue engineering}, volume={132}, ISSN={0167-577X}, url={http://dx.doi.org/10.1016/j.matlet.2014.06.036}, DOI={10.1016/j.matlet.2014.06.036}, abstractNote={Rapid degradation of magnesium (Mg) alloys is the major drawback preventing these materials from being applicable as tissue engineering scaffolds. In order to resolve this issue, in this paper, porous Mg scaffolds coated by polycaprolactone (PCL) were synthesized and their material properties and in vitro biodegradation were fully examined. The results indicated that PCL coating can significantly enhance the compressive strength and degradation resistance of Mg scaffolds. We showed that while the uncoated Mg scaffold degrades completely (100% weight loss) after 72 h, the degradation (weight loss) of the Mg scaffolds coated by 3% and 6% PCL is only 36% and 23%, respectively. Thus PCL-coated Mg scaffolds, as a biodegradable metal scaffold, can potentially have a promising application in bone tissue engineering.}, journal={Materials Letters}, publisher={Elsevier BV}, author={Yazdimamaghani, Mostafa and Razavi, Mehdi and Vashaee, Daryoosh and Tayebi, Lobat}, year={2014}, month={Oct}, pages={106–110} }
@article{salahinejad_hadianfard_vashaee_tayebi_2014, title={Effect of precursor solution pH on the structural and crystallization characteristics of sol–gel derived nanoparticles}, volume={589}, ISSN={0925-8388}, url={http://dx.doi.org/10.1016/j.jallcom.2013.11.178}, DOI={10.1016/j.jallcom.2013.11.178}, abstractNote={This paper concerns with the effect of pH on the structure and crystallization behavior of particulate sol–gel derived zirconium titanate. According to differential scanning calorimetry, it was found that the thermal stability of the synthesized amorphous particles was enhanced by increasing the precursor solution pH value from 4 to 10, as confirmed by X-ray diffraction. Transmission electron microscopy studies on the xerogel and crystallized nanoparticles showed that the pH value does not fairly affect their size and morphology; thus, these structural features cannot have a meaningful contribution to the detected crystallization difference. The realized thermal behavior was explained based on a mechanism relating to the adsorption of hydroxide ions (OH−) existing in the medium to metallic hydroxide precipitates synthesized during the sol–gel process. In this regard, it was speculated that the more the pH value is increased, as reasonably accompanied by the more hydroxide adsorption, the more the crystallization event is inhibited.}, journal={Journal of Alloys and Compounds}, publisher={Elsevier BV}, author={Salahinejad, E. and Hadianfard, M.J. and Vashaee, D. and Tayebi, L.}, year={2014}, month={Mar}, pages={182–184} }
@article{shabafrooz_mozafari_vashaee_tayebi_2014, title={Electrospun Nanofibers: From Filtration Membranes to Highly Specialized Tissue Engineering Scaffolds}, volume={14}, ISSN={1533-4880 1533-4899}, url={http://dx.doi.org/10.1166/jnn.2014.9195}, DOI={10.1166/jnn.2014.9195}, abstractNote={Electrospinning is a widely used technique to produce continuous polymeric fibers ranging from 2 nm to several micrometers. This technique is not only employed in research laboratories, but it is also increasingly being applied in different industrial fields in the last few decades as a highly versatile and cost-effective technology. Compared to conventional techniques for fiber fabrication, electrospinning can fabricate fibers in a more desirable size (e.g., nanoscale). Nanofibers are generated by the application of a strong electric field on polymer solution. Over the years, more than 200 polymers have been electrospun for various applications. In this review, our aim was to present an overview of the electrospinning technique and its potential applications. We covered the basic principles of the electrospinning technique and parameters which significantly affect the fiber morphology. The most recent work on electrospinning nanofibers for blending polymers, filtration, energy, sensing and biomedical applications was also presented in this review.}, number={1}, journal={Journal of Nanoscience and Nanotechnology}, publisher={American Scientific Publishers}, author={Shabafrooz, Vahid and Mozafari, Masoud and Vashaee, Daryoosh and Tayebi, Lobat}, year={2014}, month={Jan}, pages={522–534} }
@article{yazdimamaghani_vashaee_assefa_shabrangharehdasht_rad_eastman_walker_madihally_köhler_tayebi_2014, title={Green synthesis of a new gelatin-based antimicrobial scaffold for tissue engineering}, volume={39}, ISSN={0928-4931}, url={http://dx.doi.org/10.1016/j.msec.2014.03.007}, DOI={10.1016/j.msec.2014.03.007}, abstractNote={With the aim of developing appropriate scaffolds for tissue engineering to suppress the formation of biofilms, an effective one-pot process was applied in this study to produce scaffolds with inherent antibacterial activity. A new method to synthesize genipin-crosslinked gelatin/nanosilver scaffolds with "green" in situ formation of silver nanoparticles by heat treatment is presented in this paper. In this procedure, toxic solvents, reducing agents, and stabilizing agents are avoided. UV-visible absorption spectra of the synthesized gelatin/nanosilver solutions were obtained immediately and three months after the synthesis revealing the presence and high stability of the silver nanoparticles. The TEM of gelatin/nanosilver solutions showed silver particles with spherical shapes that were less than 5nm in size. Interestingly, contact angle was found to increase from 80° to 125° with the increase in concentration of nanosilver in gelatin. All gelatin/nanosilver solutions showed antimicrobial activity against Staphylococcus aureus and Escherichia coli. However, only the highest concentration showed antifungal effects against Candida albicans pathogens. Scaffolds were prepared by a lyophilization technique from this solution and their antimicrobial activities were examined. Introducing this facile green one-pot process of synthesizing scaffolds with antimicrobial and anti-biofilm properties may lead to key applications in tissue engineering techniques.}, journal={Materials Science and Engineering: C}, publisher={Elsevier BV}, author={Yazdimamaghani, Mostafa and Vashaee, Daryoosh and Assefa, Senait and Shabrangharehdasht, Mitra and Rad, Armin Tahmasbi and Eastman, Margaret A. and Walker, Kenneth J. and Madihally, Sundar V. and Köhler, Gerwald A. and Tayebi, Lobat}, year={2014}, month={Jun}, pages={235–244} }
@article{yazdimamaghani_vashaee_assefa_walker_madihally_köhler_tayebi_2014, title={Hybrid Macroporous Gelatin/Bioactive-Glass/Nanosilver Scaffolds with Controlled Degradation Behavior and Antimicrobial Activity for Bone Tissue Engineering}, volume={10}, ISSN={1550-7033}, url={http://dx.doi.org/10.1166/jbn.2014.1783}, DOI={10.1166/jbn.2014.1783}, abstractNote={A new composition of gelatin/bioactive-glass/silver nanoparticle was synthesized and employed to prepare antibacterial macroporous scaffolds with potential applications in bone tissue engineering. A set of macroporous nanocomposite scaffolds were developed from an aqueous solution of gelatin by freeze-drying and crosslinking using genipin at ambient temperature. Silver nanoparticles were successfully synthesized in situ in gelatin solution by heat treatment reduction as a simple and "green" method in which gelatin acted as a natural reducing and stabilizing agent. The effect of the incorporation of the bioactive-glass and the silver nanoparticle concentration on the physicochemical properties of the scaffolds, such as the gel fraction, porosity, in vitro enzyme degradation, morphology, and swelling behavior was studied. Furthermore, the in vitro viability of human mesenchymal stem cells (hMSC) and the antibacterial activity against gram-negative Escherichia coli and gram-positive Staphylococcus aureus were tested on the scaffolds. It was found that upon the addition of silver nanoparticles the porosity, pore size, swelling, and antibacterial properties were enhanced. The silver nanoparticles increased the in vitro enzyme degradation in samples without bioactive-glass; however, the degradation was remarkably reduced by addition of bioactive-glass. In addition, formation of apatite particles, the main inorganic constituent of the bone, on the surface of the bioactive-glass containing scaffolds were confirmed after immersion in simulated body fluid (SBF). The viability of hMSC on the scaffold suggested that gelatin/bioactive-glass/nanosilver scaffolds can be used as an antibacterial scaffolds.}, number={6}, journal={Journal of Biomedical Nanotechnology}, publisher={American Scientific Publishers}, author={Yazdimamaghani, M. and Vashaee, D. and Assefa, S. and Walker, K .J. and Madihally, S. V. and Köhler, G .A. and Tayebi, L.}, year={2014}, month={Jun}, pages={911–931} }
@article{razavi_fathi_savabi_vashaee_tayebi_2014, title={Improvement of Biodegradability, Bioactivity, Mechanical Integrity and Cytocompatibility Behavior of Biodegradable Mg Based Orthopedic Implants Using Nanostructured Bredigite (Ca7MgSi4O16) Bioceramic Coated via ASD/EPD Technique}, volume={42}, ISSN={0090-6964 1573-9686}, url={http://dx.doi.org/10.1007/s10439-014-1084-7}, DOI={10.1007/s10439-014-1084-7}, number={12}, journal={Annals of Biomedical Engineering}, publisher={Springer Science and Business Media LLC}, author={Razavi, Mehdi and Fathi, Mohammadhossein and Savabi, Omid and Vashaee, Daryoosh and Tayebi, Lobat}, year={2014}, month={Aug}, pages={2537–2550} }
@article{razavi_fathi_savabi_vashaee_tayebi_2014, title={In vitro Evaluations of Anodic Spark Deposited AZ91 Alloy as Biodegradable Metallic Orthopedic Implant}, volume={4}, ISSN={2347-565X}, url={http://dx.doi.org/10.9734/arrb/2014/10173}, DOI={10.9734/arrb/2014/10173}, number={24}, journal={Annual Research & Review in Biology}, publisher={SCIENCEDOMAIN international}, author={Razavi, M. and Fathi, M. and Savabi, O. and Vashaee, D. and Tayebi, L.}, editor={Perry, GeorgeEditor}, year={2014}, month={Jan}, pages={3716–3733} }
@article{razavi_fathi_savabi_vashaee_tayebi_2014, title={In vitro study of nanostructured diopside coating on Mg alloy orthopedic implants}, volume={41}, ISSN={0928-4931}, url={http://dx.doi.org/10.1016/j.msec.2014.04.039}, DOI={10.1016/j.msec.2014.04.039}, abstractNote={The high corrosion rate of Mg alloys has hindered their application in various areas, particularly for orthopedic applications. In order to decrease the corrosion rate and to improve the bioactivity, mechanical stability and cytocompatibility of the Mg alloy, nanostructured diopside (CaMgSi2O6) has been coated on AZ91 Mg alloy using a combined micro arc oxidation (MAO) and electrophoretic deposition (EPD) method. The crystalline structure, the morphology and the composition of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Electrochemical corrosion test, immersion test, and compression test were used to evaluate the corrosion resistance, the in vitro bioactivity and the mechanical stability of the samples, respectively. The cytocompatibility of the samples was tested by the cell viability and the cell attachment of L-929 cells. The results confirmed that the diopside coating not only slows down the corrosion rate, but also enhances the in vitro bioactivity, mechanical stability and cytocompatibility of AZ91 Mg alloy. Therefore, Mg alloy coated with nanostructured diopside offers a promising approach for biodegradable bone implants.}, journal={Materials Science and Engineering: C}, publisher={Elsevier BV}, author={Razavi, Mehdi and Fathi, Mohammadhossein and Savabi, Omid and Vashaee, Daryoosh and Tayebi, Lobat}, year={2014}, month={Aug}, pages={168–177} }
@article{razavi_fathi_savabi_vashaee_tayebi_2014, title={In vivo study of nanostructured akermanite/PEO coating on biodegradable magnesium alloy for biomedical applications}, volume={103}, ISSN={1549-3296}, url={http://dx.doi.org/10.1002/jbm.a.35324}, DOI={10.1002/jbm.a.35324}, abstractNote={The major issue for biodegradable magnesium alloys is the fast degradation and release of hydrogen gas. In this article, we aim to overcome these disadvantages by using a surface modified magnesium implant. We have recently coated AZ91 magnesium implants by akermanite (Ca2MgSi2O7) through the combined electrophoretic deposition (EPD) and plasma electrolytic oxidation (PEO) methods. In this work, we performed the in vitro and in vivo examinations of these coated implants using L-929 cell line and rabbit animal model. The in vitro study confirmed the higher cytocompatibility of the coated implants compare to the uncoated ones. For the in vivo experiment, the rod samples were implanted into the greater trochanter of rabbits and monitored for two months. The results indicated a noticeable biocompatibility improvement of the coated implants which includes slower implant weight loss, reduction in Mg ion released from the coated samples in the blood plasma, lower release of hydrogen bubbles, increase in the amount of bone formation and ultimately lower bone inflammation after the surgery according to the histological images. Our data exemplifies that the proper surface treatment of the magnesium implants can improve their biocompatibility under physiological conditions to make them applicable in clinical uses. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 1798–1808, 2015.}, number={5}, journal={Journal of Biomedical Materials Research Part A}, publisher={Wiley}, author={Razavi, Mehdi and Fathi, Mohammadhossein and Savabi, Omid and Vashaee, Daryoosh and Tayebi, Lobat}, year={2014}, month={Sep}, pages={1798–1808} }
@article{razavi_fathi_savabi_razavi_heidari_manshaei_vashaee_tayebi_2014, title={In vivo study of nanostructured diopside (CaMgSi2O6) coating on magnesium alloy as biodegradable orthopedic implants}, volume={313}, ISSN={0169-4332}, url={http://dx.doi.org/10.1016/j.apsusc.2014.05.130}, DOI={10.1016/j.apsusc.2014.05.130}, abstractNote={In order to improve the corrosion resistance and bioactivity of a biodegradable magnesium alloy, we have recently prepared a nanostructured diopside (CaMgSi2O6) coating on AZ91 magnesium alloy through a combined micro-arc oxidation (MAO) and electrophoretic deposition (EPD) method (reported elsewhere). In this work, we performed a detailed biocompatibility analysis of the implants made by this material and compared their performance with those of the uncoated and micro arc oxidized magnesium implants. The biocompatibility evaluation of samples was performed by culturing L-929 cells and in vivo animal study, including implantation of samples in greater trochanter of rabbits, radiography and histological examinations. The results from both the in vitro and in vivo studies indicated that the diopside/MAO coated magnesium implant significantly enhanced cell viability, biodegradation resistance and new bone formation compared with both the uncoated and the micro-arc oxidized magnesium implants. Our data provides an example of how the proper surface treatment of magnesium implants can overcome their drawbacks in terms of high degradation rate and gas bubble formation under physiological conditions.}, journal={Applied Surface Science}, publisher={Elsevier BV}, author={Razavi, Mehdi and Fathi, Mohammadhossein and Savabi, Omid and Razavi, Seyed Mohammad and Heidari, Fariba and Manshaei, Maziar and Vashaee, Daryoosh and Tayebi, Lobat}, year={2014}, month={Sep}, pages={60–66} }
@article{salahinejad_hadianfard_vashaee_tayebi_2014, title={Influence of annealing temperature on the structural and anti-corrosion characteristics of sol–gel derived, spin-coated thin films}, volume={40}, ISSN={0272-8842}, url={http://dx.doi.org/10.1016/j.ceramint.2013.10.023}, DOI={10.1016/j.ceramint.2013.10.023}, abstractNote={Recently, an aqueous particulate sol–gel process using metallic chloride precursors was introduced to synthesize zirconium titanate. In this paper, the effect of annealing temperature on the structural and corrosion protection characteristics of spin-coated thin films obtained from this sol–gel system was investigated. Based on scanning electron microscopy, transmission electron microscopy, atomic force microscopy, and spectroscopic reflectometry studies, it was found that the flatness and thickness of the thin films were decreased by increasing the annealing temperature. Also, the corrosion protection of stainless steel AISI 316L provided by the prepared coatings, as analyzed by electrochemical potentiodynamic polarization experiments in a simulated body fluid, was improved in this order: 500 °C-annealed sample<900 °C-annealed sample<700 °C-annealed sample, attributed to a compromise between the defect density and the adhesion of the films to the substrate.}, number={2}, journal={Ceramics International}, publisher={Elsevier BV}, author={Salahinejad, E. and Hadianfard, M.J. and Vashaee, D. and Tayebi, L.}, year={2014}, month={Mar}, pages={2885–2890} }
@article{satyala_tahmasbi rad_zamanipour_norouzzadeh_krasinski_tayebi_vashaee_2014, title={Influence of germanium nano-inclusions on the thermoelectric power factor of bulk bismuth telluride alloy}, volume={115}, ISSN={0021-8979 1089-7550}, url={http://dx.doi.org/10.1063/1.4873239}, DOI={10.1063/1.4873239}, abstractNote={Nanocomposite thermoelectric compound of bismuth telluride (Bi2Te3) with 5 at. % germanium nano-inclusions was prepared via mechanically alloying and sintering techniques. The influence of Ge nano-inclusions and long duration annealing on the thermoelectric properties of nanostructured Bi2Te3 were investigated. It was found that annealing has significant effect on the carrier concentration, Seebeck coefficient, and the power factor of the thermoelectric compound. The systematic heat treatment also reduced the density of donor type defects thereby decreasing the electron concentration. While the as-pressed nanocomposite materials showed n-type properties, it was observed that with the increase of annealing time, the nanocomposite gradually transformed to an abundantly hole-dominated (p-type) sample. The long duration annealing (∼500 h) resulted in a significantly enhanced electrical conductivity pertaining to the augmentation in the density and the structural properties of the sample. Therefore, a simultaneous enhancement in both electrical and Seebeck coefficient characteristics resulted in a remarkable increase in the thermoelectric power factor.}, number={20}, journal={Journal of Applied Physics}, publisher={AIP Publishing}, author={Satyala, Nikhil and Tahmasbi Rad, Armin and Zamanipour, Zahra and Norouzzadeh, Payam and Krasinski, Jerzy S. and Tayebi, Lobat and Vashaee, Daryoosh}, year={2014}, month={May}, pages={204308} }
@article{mozafari_salahinejad_sharifi-asl_macdonald_vashaee_tayebi_2014, title={Innovative surface modification of orthopaedic implants with positive effects on wettability andin vitroanti-corrosion performance}, volume={30}, ISSN={0267-0844 1743-2944}, url={http://dx.doi.org/10.1179/1743294414y.0000000309}, DOI={10.1179/1743294414y.0000000309}, abstractNote={In this work, sol–gel derived bioactive glass/zirconium titanate coatings were uniformly deposited on stainless steel orthopaedic implants, by using carboxymethyl cellulose as a particulate dispersant in the sol. The surface features, wetting, and in vitro electrochemical corrosion behaviour of the coated samples were evaluated. It was found that, by applying the coating on the substrate, the water contact angle was decreased, which is indicative of an improvement in the implant hydrophilicity. Also, the coating improved the corrosion resistance of the metallic implant, as realised by an increase in the corrosion potential and a decrease in the corrosion current density. Indeed, this coating acted as a physical protective barrier which retards the electrolyte access to the metal surface and thereby electrochemical processes.}, number={9}, journal={Surface Engineering}, publisher={Informa UK Limited}, author={Mozafari, M. and Salahinejad, E. and Sharifi-Asl, S. and Macdonald, D. D. and Vashaee, D. and Tayebi, L.}, year={2014}, month={Aug}, pages={688–692} }
@article{razavi_fathi_savabi_vashaee_tayebi_2014, title={Micro-arc oxidation and electrophoretic deposition of nano-grain merwinite (Ca3MgSi2O8) surface coating on magnesium alloy as biodegradable metallic implant}, volume={46}, ISSN={0142-2421}, url={http://dx.doi.org/10.1002/sia.5465}, DOI={10.1002/sia.5465}, abstractNote={Magnesium alloys are promising biomaterials as biodegradable implant for orthopedic applications. However, their low corrosion resistance and poor bioactivity have prohibited their implant applications. In order to enhance these two properties, a nano-grain merwinite coating was prepared on magnesium alloy. Its corrosion and the bioactivity behavior were characterized with electrochemical and immersion tests. The results showed that the nano-grain merwinite coating can improve both the corrosion resistance and the bioactivity of the magnesium alloy making it an appropriate material for biodegradable bone implants. Copyright © 2014 John Wiley & Sons, Ltd.}, number={6}, journal={Surface and Interface Analysis}, publisher={Wiley}, author={Razavi, Mehdi and Fathi, Mohammadhossein and Savabi, Omid and Vashaee, Daryoosh and Tayebi, Lobat}, year={2014}, month={Mar}, pages={387–392} }
@article{yazdimamaghani_razavi_vashaee_tayebi_2014, title={Microstructural and mechanical study of PCL coated Mg scaffolds}, volume={30}, ISSN={0267-0844 1743-2944}, url={http://dx.doi.org/10.1179/1743294414Y.0000000307}, DOI={10.1179/1743294414Y.0000000307}, abstractNote={In recent years, attention has been focused on the magnesium (Mg) as a promising material in biodegradable metallic scaffolds for bone tissue engineering. Since an orthopedic scaffold is supposed to repair and regenerate fractured bones, its mechanical integrity is vital throughout the healing process. In this study, a biocompatible polymeric layer made of polycaprolactone (PCL) in different concentrations of 3% w/v and 6% w/v was coated on the surface of Mg scaffolds. The structural characteristics and mechanical behaviour of the Mg scaffolds during the immersion in physiological saline solution (PSS) were investigated. According to our results, the PCL coating hindered the diminution of mechanical stability of scaffolds to provide adequate support for bone healing. Specifically, scaffold coated with 3% w/v and 6% w/v PCL demonstrated 24 and 100% improvement in the elastic modulus and 41 and 83% enhancement in compressive strength respectively, after 24 h immersion in PSS, compare to the uncoated scaffold. Thus, PCL coating of Mg scaffolds may be a promising approach in the development of mechanically stable bone scaffolds.}, number={12}, journal={Surface Engineering}, publisher={Informa UK Limited}, author={Yazdimamaghani, M. and Razavi, M. and Vashaee, D. and Tayebi, L.}, year={2014}, month={Aug}, pages={920–926} }
@article{razavi_fathi_savabi_hashemi beni_vashaee_tayebi_2014, title={Nanostructured merwinite bioceramic coating on Mg alloy deposited by electrophoretic deposition}, volume={40}, ISSN={0272-8842}, url={http://dx.doi.org/10.1016/j.ceramint.2014.02.020}, DOI={10.1016/j.ceramint.2014.02.020}, abstractNote={Magnesium (Mg) alloys have recently attracted much attention as degradable metallic implants for bone fracture healing. A biodegradable osteosynthetic implant material will remove the need for the implant removal surgery after the bone healing process. However, the high corrosion rate of the Mg alloys in the body fluid has prevented their clinical application as implants. In the present study, a nanostructured merwinite (Ca3MgSi2O8) bioceramic coating was prepared on AZ91 Mg alloy in order to improve its corrosion resistance, bioactivity, mechanical stability and cytocompatibility. The coating was deposited by electrophoretic deposition assisted micro arc oxidation. The phase composition and the surface morphology of the samples were characterized by X-ray diffraction and electron microscopy. The corrosion, bioactivity and mechanical behavior of the samples were investigated by electrochemical measurements, immersion into simulated body fluid (SBF) and compression tests. The cytocompatibility of the samples was evaluated by a cell culture test. The results showed that the nanostructured merwinite coating not only improved the corrosion resistance, but also enhanced the bioactivity, mechanical stability and cytocompatibility of the AZ91 Mg alloy.}, number={7}, journal={Ceramics International}, publisher={Elsevier BV}, author={Razavi, Mehdi and Fathi, Mohammadhossein and Savabi, Omid and Hashemi Beni, Batoul and Vashaee, Daryoosh and Tayebi, Lobat}, year={2014}, month={Aug}, pages={9473–9484} }
@article{norouzzadeh_myles_vashaee_2014, title={Prediction of Giant Thermoelectric Power Factor in Type-VIII Clathrate Si-46}, volume={4}, ISSN={["2045-2322"]}, DOI={10.1038/srep07028}, abstractNote={Clathrate materials have been the subject of intense interest and research for thermoelectric application. Nevertheless, from the very large number of conceivable clathrate structures, only a small fraction of them have been examined. Since the thermal conductivity of clathrates is inherently small due to their large unit cell size and open-framework structure, the current research on clathrates is focused on finding the ones with large thermoelectric power factor. Here we predict an extraordinarily large power factor for type-VIII clathrate Si(46). We show the existence of a large density of closely packed elongated ellipsoidal carrier pockets near the band edges of this so far hypothetical material structure, which is higher than that of the best thermoelectric materials known today. The high crystallographic symmetry near the energy band edges for Si(46)-VIII clathrates is responsible for the formation of such a large number of carrier pockets.}, journal={SCIENTIFIC REPORTS}, author={Norouzzadeh, Payam and Myles, Charles W. and Vashaee, Daryoosh}, year={2014}, month={Nov} }
@inbook{mozafari_shabafrooz_yazdimamaghani_vashaee_tayebi_2014, place={Manchester, United Kingdom}, title={Recent trends in tissue engineering applications of atom transfer radical polymerization}, ISBN={9781910086018}, booktitle={Nanomedicine}, publisher={One Central Press}, author={Mozafari, M. and Shabafrooz, V and Yazdimamaghani, M. and Vashaee, D. and Tayebi, L.}, editor={Seifalian, A. and de Mel, Achala and Kalaskar, Deepak M.Editors}, year={2014}, pages={490–528} }
@article{satyala_tahmasbi rad_zamanipour_norouzzadeh_krasinski_tayebi_vashaee_2014, title={Reduction of thermal conductivity of bulk nanostructured bismuth telluride composites embedded with silicon nano-inclusions}, volume={115}, ISSN={0021-8979 1089-7550}, url={http://dx.doi.org/10.1063/1.4861727}, DOI={10.1063/1.4861727}, abstractNote={Bulk nanostructured bismuth telluride (Bi2Te3) composite with silicon nano-crystallite inclusions was synthesized via sintering approach. The effect of the composite structure formed by the addition of miniscule quantity (5 at. %) of silicon on the thermoelectric properties of bulk nanostructured Bi2Te3 is shown via a 50% drop in thermal conductivity accompanied with a simultaneous enhancement in the Seebeck coefficient. We demonstrate that the addition of silicon nano-inclusions to the nanostructured compound combined with a systematic thermal treatment beneficially reduces the thermal conductivity to less than 1.0 W/mK over the entire temperature range of 300 K to 525 K. It is shown that the combinatorial techniques of nanostructuring, nano-inclusions, and annealing are effective in reducing thermal conductivity by a significant magnitude. This low thermal conductivity is comparable to that of Bi2Te3 based superlattices and significantly lower than that of bulk Bi2Te3. The technique is extendable to (Bi,Se)2(Sb,Te)3 based thermoelectric alloys for enhancing the figure-of-merit.}, number={4}, journal={Journal of Applied Physics}, publisher={AIP Publishing}, author={Satyala, Nikhil and Tahmasbi Rad, Armin and Zamanipour, Zahra and Norouzzadeh, Payam and Krasinski, Jerzy S. and Tayebi, Lobat and Vashaee, Daryoosh}, year={2014}, month={Jan}, pages={044304} }
@article{satyala_krasinski_vashaee_2014, title={Simultaneous enhancement of mechanical and thermoelectric properties of polycrystalline magnesium silicide with conductive glass inclusion}, volume={74}, ISSN={1359-6454}, url={http://dx.doi.org/10.1016/j.actamat.2014.04.007}, DOI={10.1016/j.actamat.2014.04.007}, abstractNote={Thermal fatigue and mechanical failure are two challenging aspects of thermoelectric (TE) module design and fabrication. Among the well-known TE materials with high conversion efficiencies are various brittle semiconductors or ceramics. However, formation of microcracks during fabrication and mechanical failure due to the high stress response in the course of thermal cycles are commonly observed in such material systems. In this work, we report the results of a novel technique to improve the mechanical and TE properties of magnesium silicide (Mg2Si) via addition of a small quantity (0.25–1 vol.%) of conductive glass-frit. Mechanically alloyed and hot-pressed Mg2Si specimens separately doped with 2 at.% Bi and 2 at.% Al were sintered at 1173 and 1123 K, respectively. The TE properties of both compounds were characterized by measurements of electrical resistivity (ρ), Seebeck coefficient (S) and thermal conductivity (κ) in the temperature range 300–970 K. The beneficial effects of addition of a minuscule quantity of Mg–Si–B–R-based (R = rare earth) conductive glass-frit to Al-doped Mg2Si samples were investigated. Both Al-doped and Bi-doped Mg2Si specimen were tested for mechanical reliability using diametric compression tests. Power factors times temperature (S2σT) of >2 W m–1 K–1 were obtained from Al-doped samples containing conductive glass-frit. It was also found that addition of 1% of the conductive glass-frit results in significant improvement of the mechanical properties of Mg2Si by eliminating microcracks in the brittle Mg2Si system. Nearly 150% improvement was observed in the mechanical strength of the Al-doped samples reinforced with conductive glass-frit as compared to the samples without glass-frit.}, journal={Acta Materialia}, publisher={Elsevier BV}, author={Satyala, Nikhil and Krasinski, Jerzy S. and Vashaee, Daryoosh}, year={2014}, month={Aug}, pages={141–150} }
@article{norouzzadeh_myles_vashaee_2014, title={Structural, electronic, phonon and thermodynamic properties of hypothetical type-VIII clathrates Ba8Si46 and Ba8Al16Si30 investigated by first principles}, volume={587}, ISSN={0925-8388}, url={http://dx.doi.org/10.1016/j.jallcom.2013.10.190}, DOI={10.1016/j.jallcom.2013.10.190}, abstractNote={We present the results of first principles calculations of the structural, electronic, elastic, vibrational, and thermodynamic properties of the hypothetical silicon-based, guest containing type-VIII clathrates Ba8Si46 and Ba8Al16Si30. We obtained the lattice constant, formation energy, band structure, density of states, elastic constants, sound velocity, and Debye temperature using the density functional theory with generalized gradient approximation (GGA). We calculated phonon dispersion and vibrational density of states spectra using the density functional perturbation energy within GGA. We computed the temperature dependent specific heat, vibrational entropy, and vibrational Helmholtz free energy by utilizing quasi-harmonic approximation. We found that replacing some silicon atoms in the framework with aluminum atoms leads to the decrease of the fundamental band gap from 1.0 in Ba8Si46 to 0.18 eV in Ba8Al16Si30. Moreover, the guest Ba atoms produced localized phonon modes lying below 1.2, 1.8 THz for Ba8Si46, and Ba8Al16Si30, respectively, which lead to the reduction of the acoustic bandwidth of the host material. The effect of replacing Si atoms with Al on the properties of the interest is also discussed.}, journal={Journal of Alloys and Compounds}, publisher={Elsevier BV}, author={Norouzzadeh, Payam and Myles, Charles W. and Vashaee, Daryoosh}, year={2014}, month={Feb}, pages={474–480} }
@article{razavi_fathi_savabi_hashemi beni_vashaee_tayebi_2014, title={Surface microstructure and in vitro analysis of nanostructured akermanite (Ca2MgSi2O7) coating on biodegradable magnesium alloy for biomedical applications}, volume={117}, ISSN={0927-7765}, url={http://dx.doi.org/10.1016/j.colsurfb.2013.12.011}, DOI={10.1016/j.colsurfb.2013.12.011}, abstractNote={Magnesium (Mg) alloys, owing to their biodegradability and good mechanical properties, have potential applications as biodegradable orthopedic implants. However, several poor properties including low corrosion resistance, mechanical stability and cytocompatibility have prevented their clinical application, as these properties may result in the sudden failure of the implants during the bone healing. In this research, nanostructured akermanite (Ca2MgSi2O7) powder was coated on the AZ91 Mg alloy through electrophoretic deposition (EPD) assisted micro arc oxidation (MAO) method to modify the properties of the alloy. The surface microstructure of coating, corrosion resistance, mechanical stability and cytocompatibility of the samples were characterized with different techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), electrochemical corrosion test, immersion test, compression test and cell culture test. The results showed that the nanostructured akermanite coating can improve the corrosion resistance, mechanical stability and cytocompatibility of the biodegradable Mg alloy making it a promising material to be used as biodegradable bone implants for orthopedic applications.}, journal={Colloids and Surfaces B: Biointerfaces}, publisher={Elsevier BV}, author={Razavi, Mehdi and Fathi, Mohammadhossein and Savabi, Omid and Hashemi Beni, Batoul and Vashaee, Daryoosh and Tayebi, Lobat}, year={2014}, month={May}, pages={432–440} }
@article{tayebi_shahini_yazdimamaghani_walker_eastman_hatami-marbini_smith_ricci_madihally_vashaee_2013, title={3D conductive nanocomposite scaffold for bone tissue engineering}, ISSN={1178-2013}, url={http://dx.doi.org/10.2147/ijn.s54668}, DOI={10.2147/ijn.s54668}, abstractNote={3D conductive nanocomposite scaffold for bone tissue engineering Aref Shahini,1 Mostafa Yazdimamaghani,2 Kenneth J Walker,2 Margaret A Eastman,3 Hamed Hatami-Marbini,4 Brenda J Smith,5 John L Ricci,6 Sundar V Madihally,2 Daryoosh Vashaee,1 Lobat Tayebi2,7 1School of Electrical and Computer Engineering, Helmerich Advanced Technology Research Center, 2School of Chemical Engineering, 3Department of Chemistry, 4School of Mechanical and Aerospace Engineering, 5Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, USA; 6Department of Biomaterials and Biomimetics, New York University, New York, NY; 7School of Material Science and Engineering, Helmerich Advanced Technology Research Center, Oklahoma State University, Tulsa, OK, USA Abstract: Bone healing can be significantly expedited by applying electrical stimuli in the injured region. Therefore, a three-dimensional (3D) ceramic conductive tissue engineering scaffold for large bone defects that can locally deliver the electrical stimuli is highly desired. In the present study, 3D conductive scaffolds were prepared by employing a biocompatible conductive polymer, ie, poly(3,4-ethylenedioxythiophene) poly(4-styrene sulfonate) (PEDOT:PSS), in the optimized nanocomposite of gelatin and bioactive glass. For in vitro analysis, adult human mesenchymal stem cells were seeded in the scaffolds. Material characterizations using hydrogen-1 nuclear magnetic resonance, in vitro degradation, as well as thermal and mechanical analysis showed that incorporation of PEDOT:PSS increased the physiochemical stability of the composite, resulting in improved mechanical properties and biodegradation resistance. The outcomes indicate that PEDOT:PSS and polypeptide chains have close interaction, most likely by forming salt bridges between arginine side chains and sulfonate groups. The morphology of the scaffolds and cultured human mesenchymal stem cells were observed and analyzed via scanning electron microscope, micro-computed tomography, and confocal fluorescent microscope. Increasing the concentration of the conductive polymer in the scaffold enhanced the cell viability, indicating the improved microstructure of the scaffolds or boosted electrical signaling among cells. These results show that these conductive scaffolds are not only structurally more favorable for bone tissue engineering, but also can be a step forward in combining the tissue engineering techniques with the method of enhancing the bone healing by electrical stimuli. Keywords: conductive polymers, bone scaffold, gelatin, bioactive glass nanoparticles, PEDOT:PSS, conductive scaffold}, journal={International Journal of Nanomedicine}, publisher={Dove Medical Press Ltd.}, author={Tayebi and Shahini, Aref and Yazdimamaghani, Mostafa and Walker, Kenneth Jimmy and Eastman, Margaret and Hatami-Marbini, Hamed and Smith, Brenda and Ricci, John L. and Madihally, Sundar and Vashaee, Daryoosh}, year={2013}, month={Dec}, pages={167} }
@article{salahinejad_hadianfard_macdonald_mozafari_vashaee_tayebi_2013, title={A new double-layer sol–gel coating to improve the corrosion resistance of a medical-grade stainless steel in a simulated body fluid}, volume={97}, ISSN={0167-577X}, url={http://dx.doi.org/10.1016/j.matlet.2013.01.111}, DOI={10.1016/j.matlet.2013.01.111}, abstractNote={One of the effective ways to overcome some of the drawbacks of oxide coatings for corrosion protection of metal surfaces is the incorporation of an organic component into the inorganic network, although, commonly, film adhesion is disadvantageously affected. In this work, for the first time, by exploiting both inorganic and organic–inorganic coatings, a new double-layer thin film, which comprises ZrTiO4 as the bottom layer and ZrTiO4–PMMA as the top layer, was deposited on a medical-grade stainless steel substrate via a sol–gel spin coating method. According to potentiodynamic polarization experiments in a simulated body fluid, the substrate coated with this film exhibited superior corrosion resistance, compared with the same steel coated with purely inorganic ZrTiO4 and hybrid ZrTiO4–PMMA films. The superior corrosion resistance of the newly developed coating was found to be due to simultaneously the good adhesion of the lower, inorganic film and the low defect density of the upper, hybrid film.}, journal={Materials Letters}, publisher={Elsevier BV}, author={Salahinejad, E. and Hadianfard, M.J. and Macdonald, D.D. and Mozafari, M. and Vashaee, D. and Tayebi, L.}, year={2013}, month={Apr}, pages={162–165} }
@article{zamanipour_krasinski_vashaee_2013, title={Comparison of boron precipitation in p-type bulk nanostructured and polycrystalline silicon germanium alloy}, volume={113}, ISSN={0021-8979 1089-7550}, url={http://dx.doi.org/10.1063/1.4801388}, DOI={10.1063/1.4801388}, abstractNote={Boron precipitation process and its effect on electronic properties of p-type bulk nanostructured silicon germanium (Si0.8Ge0.2) compared with large grain polycrystalline Si0.8Ge0.2 have been studied. The structures were synthesized and their thermoelectric properties were measured versus temperature during heating and cooling cycles. The experimental data showed stronger temperature variation of Seebeck coefficient, carrier concentration, and conductivity in the nanostructured Si0.8Ge0.2 compared with the polycrystalline form indicating stronger boron precipitation in this structure. The electrical properties of both samples were calculated using a multi-band semi-classical model. The theoretical calculations confirm that the increase of boron precipitation in the nanostructured Si0.8Ge0.2 is responsible for its higher thermal instability. Since the thermoelectric properties of the nanostructured sample degrade as a result of thermal cycling, the material is appropriate only for continuous operation at high temperature without cooling.}, number={14}, journal={Journal of Applied Physics}, publisher={AIP Publishing}, author={Zamanipour, Zahra and Krasinski, Jerzy S. and Vashaee, Daryoosh}, year={2013}, month={Apr}, pages={143715} }
@article{fathi_moradi_habibi_vashaee_tayebi_2013, title={Digital holographic microscopy of the myelin figure structural dynamics and the effect of thermal gradient}, volume={4}, ISSN={2156-7085 2156-7085}, url={http://dx.doi.org/10.1364/boe.4.000950}, DOI={10.1364/boe.4.000950}, abstractNote={Myelin figures (MFs) are cylindrical multilamellar lipid tubes that can be found in various healthy and diseased living cells. Their formation and dynamics involve some of the most mysterious configurations that lipid molecules can adopt under certain conditions. They have been studied with different microscopy methods. Due to the frequent coiling of their structure, the usual methods of microscopy fail to give precise quantitative information about their dynamics. In this paper, we introduced Digital Holographic Microscopy (DHM) as a useful method to calculate the precise dynamical volume, thickness, surface and length of the myelin figures. As an example of DHM imaging of myelin figures, their structure and growth rate in the presence and absence of temperature gradient have been studied in this work. We showed that the thickness of a myelin figure can be changed during the first few seconds. However, after approximately ten seconds, the thickness stabilizes and does not alter significantly. We further studied the effect of the thermal gradient on the length growth. The calculation of the length growth from the measurement of the myelin figure volume shows that the length (L) grows in time (t) as [Formula: see text]at the early stage of the myelin protrusion in both the presence and the absence of the thermal gradient. However, thermal gradient facilitates the growth and increases its rate.}, number={6}, journal={Biomedical Optics Express}, publisher={The Optical Society}, author={Fathi, Narges and Moradi, Ali-Reza and Habibi, Mehdi and Vashaee, Daryoosh and Tayebi, Lobat}, year={2013}, month={May}, pages={950} }
@article{norouzzadeh_myles_vashaee_2013, title={Electronic, elastic, vibrational, and thermodynamic properties of type-VIII clathrates Ba8Ga16Sn30 and Ba8Al16Sn30 by first principles}, volume={114}, ISSN={0021-8979 1089-7550}, url={http://dx.doi.org/10.1063/1.4826213}, DOI={10.1063/1.4826213}, abstractNote={We present the results of studying electronic, elastic, vibrational, and thermodynamic properties of type-VIII clathrates Ba8Ga16Sn30 Ba8Al16Sn30 calculated from a first-principles approach. The calculations utilize the generalized gradient approximation to density functional theory. The results indicate that the Ba8Ga16Sn30 and Ba8Al16Sn30 are indirect semiconductors with fundamental band gaps of 160 meV and 315 meV, respectively. It was also found that the stiffness of Al containing type-VIII clathrate does not show any significant change against the uniform pressure, shearing, and linear strains. The phonon spectrum and the phonon state densities of these compounds as well as the Raman and infrared active modes were further calculated and the effects of replacing the Ga with Al atoms on the properties of interest were discussed. The calculated elastic, vibrational, and thermodynamic properties along with Raman and IR spectra are reported for the first time. The identification of the Raman and infrared active modes will be especially useful for the experimental characterizations of these compounds. Our calculations show that the heat capacities of these clathrates increase smoothly with temperature and approach the Dulong-Petit value at about room temperature, which agrees with the existing experimental data.}, number={16}, journal={Journal of Applied Physics}, publisher={AIP Publishing}, author={Norouzzadeh, Payam and Myles, Charles W. and Vashaee, Daryoosh}, year={2013}, month={Oct}, pages={163509} }
@article{tayebi_mozafari_el-khouri_rouhani_vashaee_2013, title={Energy Harvesting Capability of Lipid-Merocyanine Macromolecules: A New Design and Performance Model Development}, volume={90}, ISSN={0031-8655}, url={http://dx.doi.org/10.1111/php.12193}, DOI={10.1111/php.12193}, abstractNote={Light induced cis/trans isomerization in the family of merocyanine (MC) dyes offers a recyclable proton pumping ability which can potentially be used in hybrid bio-electronic devices. In this article, a hexadecyl MC dye is embedded in lipid molecules to make a macromolecular configuration of a lipid/hexadecyl MC membrane. Lipid molecules play a critical role in stabilizing the dye in a membrane structure for practical use in energy devices. In this study, we first examined the proton pumping characteristic of the lipid/hexadecyl MC membrane in a conventional photoelectrochemical cell. Next, a major modification in the cell was introduced by eliminating I2/I-electrolyte which resulted in a two-fold increase in the open circuit voltage compared with that of the conventional cell. In addition, the charging time in the new cell was reduced approximately four orders of magnitude. This research demonstrated that the newly designed lipid- MC cell can act as a promising bioelectronic device based on the green energy of photoinduced MC dye proton pumping.}, number={3}, journal={Photochemistry and Photobiology}, publisher={Wiley}, author={Tayebi, Lobat and Mozafari, Masoud and El-khouri, Rita and Rouhani, Parvaneh and Vashaee, Daryoosh}, year={2013}, month={Nov}, pages={517–521} }
@article{nozariasbmarz_tahmasbi rad_zamanipour_krasinski_tayebi_vashaee_2013, title={Enhancement of thermoelectric power factor of silicon germanium films grown by electrophoresis deposition}, volume={69}, ISSN={1359-6462}, url={http://dx.doi.org/10.1016/j.scriptamat.2013.06.025}, DOI={10.1016/j.scriptamat.2013.06.025}, abstractNote={A method based on electrophoresis deposition is demonstrated for making efficient silicon germanium thermoelectric films. The film showed a thermoelectric power factor an order of magnitude larger than the previously reported values. Theoretical modeling of the charge carrier transport showed that the enhancement of power factor is due to the large carrier mobility of the film. The method offers a cost-effective approach extendable to other materials for making efficient miniature thermoelectric devices.}, number={7}, journal={Scripta Materialia}, publisher={Elsevier BV}, author={Nozariasbmarz, Amin and Tahmasbi Rad, Armin and Zamanipour, Zahra and Krasinski, Jerzy S. and Tayebi, Lobat and Vashaee, Daryoosh}, year={2013}, month={Oct}, pages={549–552} }
@article{mozafari_moztarzadeh_vashaee_tayebi_2013, title={Erratum to “Effects of heat-treatment on physical, microstructural and optical characteristics of PbS luminescent nanocrystals” [Physica E: Low-dimens. Syst. Nanostruct. 44 (2012) 1429–1435 ]}, volume={47}, ISSN={1386-9477}, url={http://dx.doi.org/10.1016/j.physe.2012.10.015}, DOI={10.1016/j.physe.2012.10.015}, journal={Physica E: Low-dimensional Systems and Nanostructures}, publisher={Elsevier BV}, author={Mozafari, Masoud and Moztarzadeh, Fathollah and Vashaee, Daryoosh and Tayebi, Lobat}, year={2013}, month={Jan}, pages={324} }
@inbook{mozafari_shabafrooz_vashaee_tayebi_2013, title={From conventional bioceramics to modern expeditious bioactive glasses}, booktitle={Frontiers in Ceramic Science – Synthesis and Characterization, Processing and its New Emerging Applications}, author={Mozafari, Masoud and Shabafrooz, Vahid and Vashaee, Daryoosh and Tayebi, Lobat}, year={2013} }
@article{tayebi_parikh_vashaee_2013, title={Interlamellar Organization of Phase Separated Domains in Multi-Component Lipid Multilayers: Energetic Considerations}, volume={14}, ISSN={1422-0067}, url={http://dx.doi.org/10.3390/ijms14023824}, DOI={10.3390/ijms14023824}, abstractNote={A recent experimental study [1] has demonstrated the alignment of phase separated domains across hundreds of bilayer units in multicomponent stacked lipid bilayers. The origin of this alignment is the interlamellar coupling of laterally phase separated domains. Here, we develop a theoretical model that presents the energetics description of this phenomenon based on the minimization of the free energy of the system. Specifically, we use solution theory to estimate the competition between energy and entropy in different stacking configurations. The model furnishes an elemental phase diagram, which maps the domain distributions in terms of the strength of the intra- and inter-layer interactions and estimates the value of inter-layer coupling for complete alignment of domains in the stacks of five and ten bilayers. The area fraction occupied by co-existing phases was calculated for the system of the minimum free energy, which showed a good agreement with experimental observations.}, number={2}, journal={International Journal of Molecular Sciences}, publisher={MDPI AG}, author={Tayebi, Lobat and Parikh, Atul and Vashaee, Daryoosh}, year={2013}, month={Feb}, pages={3824–3833} }
@article{ma_tayebi_vashaee_chen_parikh_sinha_2013, title={Long-Range Smectic Coupling of Phase Separated Domains in Ternary Mixture Lipid Multilayers}, volume={104}, ISSN={0006-3495}, url={http://dx.doi.org/10.1016/j.bpj.2012.11.3268}, DOI={10.1016/j.bpj.2012.11.3268}, abstractNote={Lipid multilayers serve as suitable and convenient bio-mimetic systems and are broadly used for studies of lipid membrane structure and function. It is known that many mixed lipid systems undergo phase separation as a function of temperature. Here we report that, in multilayers, the lateral phase separation in the bilayers is accompanied by long-range columnar order of the two phases along the normal to the bilayers arising from the coupling of two-dimensional intra-layer phase separation and inter-layer smectic ordering. Quantitative analysis of real-time dynamical experiments of confocal florescence microscopy reveal an interplay between intra-layer domain growth and inter-layer coupling, while X-ray reflectivity studies establish that the phase-separated domains are correlated normal to the lamellae over hundreds of bilayers. Through reconstruction of relative electron density profiles, XRR data also offer insight into differences in the domain structure on nm length scales. The microscopic understanding of two coexisting and domain-aligned multilamellar phases advanced by our experiments shed new light on the role of water in organizing membrane phases in stacked bilayers - a phenomenon of possible relevance to the mechanism of inter-layer lipid-lipid interactions in biological membranes.View Large Image | View Hi-Res Image | Download PowerPoint Slide}, number={2}, journal={Biophysical Journal}, publisher={Elsevier BV}, author={Ma, Yicong and Tayebi, Lobat and Vashaee, Daryoosh and Chen, Gang and Parikh, Atul and Sinha, Sunil}, year={2013}, month={Jan}, pages={588a} }
@article{mozafari_salahinejad_shabafrooz_yazdimamaghani_vashaee_tayebi_2013, title={Multilayer bioactive glass/zirconium titanate thin films in bone tissue engineering and regenerative dentistry}, volume={8}, ISSN={1178-2013}, url={http://dx.doi.org/10.2147/IJN.S42659}, DOI={10.2147/IJN.S42659}, abstractNote={Surface modification, particularly coatings deposition, is beneficial to tissue-engineering applications. In this work, bioactive glass/zirconium titanate composite thin films were prepared by a sol-gel spin-coating method. The surface features of the coatings were studied by scanning electron microscopy, atomic force microscopy, and spectroscopic reflection analyses. The results show that uniform and sound multilayer thin films were successfully prepared through the optimization of the process variables and the application of carboxymethyl cellulose as a dispersing agent. Also, it was found that the thickness and roughness of the multilayer coatings increase nonlinearly with increasing the number of the layers. This new class of nanocomposite coatings, comprising the bioactive and inert components, is expected not only to enhance bioactivity and biocompatibility, but also to protect the surface of metallic implants against wear and corrosion.}, number={1}, journal={International Journal of Nanomedicine}, publisher={Dove Medical Press Ltd.}, author={Mozafari, Masoud and Salahinejad, Erfan and Shabafrooz, Vahid and Yazdimamaghani, Mostafa and Vashaee, Daryoosh and Tayebi, Lobat}, year={2013}, month={Apr}, pages={1665–1672} }
@article{salahinejad_hadianfard_macdonald_mozafari_vashaee_tayebi_2013, title={Multilayer zirconium titanate thin films prepared by a sol–gel deposition method}, volume={39}, ISSN={0272-8842}, url={http://dx.doi.org/10.1016/j.ceramint.2012.07.058}, DOI={10.1016/j.ceramint.2012.07.058}, abstractNote={Abstract Zirconium titanate multilayer thin films were prepared by an aqueous particulate sol–gel process followed by spin coating. The obtained structures were studied by transmission electron microscope, scanning electron microscope, atomic force microscope, and spectroscopic reflection analyses. According to the results, sound thin films up to three layers were developed, accompanied by an increase in thickness and roughness by increasing the number of the layers. It was also found that the coatings consist of globular nanoparticles with an average diameter of 50 nm. Considering the contribution of roughness to biological responses, the optimization of the surface characteristics to meet an optimal performance seems to be a challenging issue, which demands future studies.}, number={2}, journal={Ceramics International}, publisher={Elsevier BV}, author={Salahinejad, E. and Hadianfard, M.J. and Macdonald, D.D. and Mozafari, M. and Vashaee, D. and Tayebi, L.}, year={2013}, month={Mar}, pages={1271–1276} }
@inbook{satyala_norouzzadeh_vashaee_2013, title={Nano Bulk Thermoelectrics: Concepts, Techniques, and Modeling}, ISBN={9783319020112 9783319020129}, ISSN={2195-2159 2195-2167}, url={http://dx.doi.org/10.1007/978-3-319-02012-9_4}, DOI={10.1007/978-3-319-02012-9_4}, abstractNote={The beneficial effects of nanostructured material systems have provided a significant momentum to accomplish high-efficiency thermoelectric materials for power generation and cooling applications. The quantum size effects have been widely explored in order to shrink the contribution of lattice thermal conductivity of the thermoelectric systems, thereby enhancing the overall figure-of-merit. Modifying the nanoscale level structural features and the creation of additional phonon scattering sites in the form of grain boundary interfaces became the basis for fabrication of nanostructured materials. The requirement of specific physical features in nanostructured thermoelectrics also brought a variety of changes to the fabrication processes. In this chapter, we review some of the prominent techniques for fabrication of such nanostructured material systems. An overview of the concepts and techniques for theoretical modeling of the charge carrier and phonon transport mechanisms in the interfacial regions is presented. Further, the constructive effects of nanostructuring in thermoelectric materials are discussed based on a theoretical approach via Boltzmann transport equation under the relaxation time approximation. The calculations are used to demonstrate the advantages and disadvantages of nanoscale effects in the well-known material systems of Si x Ge1−x and Mg2Si.}, booktitle={Lecture Notes in Nanoscale Science and Technology}, publisher={Springer International Publishing}, author={Satyala, Nikhil and Norouzzadeh, Payam and Vashaee, Daryoosh}, year={2013}, month={Oct}, pages={141–183} }
@article{rouhani_salahinejad_kaul_vashaee_tayebi_2013, title={Nanostructured zirconium titanate fibers prepared by particulate sol–gel and cellulose templating techniques}, volume={568}, ISSN={0925-8388}, url={http://dx.doi.org/10.1016/j.jallcom.2013.03.142}, DOI={10.1016/j.jallcom.2013.03.142}, abstractNote={In this paper, a method for cost-effective production of nanostructured zirconium titanate (ZrTiO4) fibers is introduced. In this method, ZrTiO4 fibers were synthesized by a sol–gel technique using cellulose fibers as the template. The resultant structures were studied by transmission electron microscopy, X-ray diffraction, scanning electron microscopy, and Brunauer–Emmett–Teller (BET) analyses. The photocatalytic activity of the fiber was compared to that of ZrTiO4 powders prepared by the same sol–gel method, in dark and under UVA and UVC radiations. According to the results, after calcination accompanied by the template removal, the ZrTiO4 fiber consists of uniformly-deposited, crystalline nanoparticles. This nanostructured fiber exhibited a higher surface area and a higher porosity compared with the ZrTiO4 powders, resulting in considerably higher photocatalytic characteristics, as confirmed by the experiment. The large surface area and the enhanced photocatalytic activity of the ZrTiO4 fibers also offer applications in sensors and bioactive films.}, journal={Journal of Alloys and Compounds}, publisher={Elsevier BV}, author={Rouhani, P. and Salahinejad, E. and Kaul, R. and Vashaee, D. and Tayebi, L.}, year={2013}, month={Aug}, pages={102–105} }
@article{tayebi_vashaee_2013, title={On the estimation of the unknown reactivity coefficients in a CANDU reactor}, volume={53}, ISSN={0306-4549}, url={http://dx.doi.org/10.1016/j.anucene.2012.07.025}, DOI={10.1016/j.anucene.2012.07.025}, abstractNote={A space-time kinetics based inverse architecture method is suggested to analyze the reactivity variations associated with power excursions in a generic CANDU reactor. It is intended to provide diagnosis tools to gain enhanced control thereby ensuring safe operation of the plant. A methodology for analyzing the data available from the in core flux detectors and extracting the unknown reactivity coefficients is presented. The proposed system uses a reference model in conjunction with an optimal estimator. The reference model is composed of a state space representation of the space-time dynamics of neutron flux in the core, based on modal expansion approximation, and a time domain optimal estimator filter. We investigated three different estimation techniques based on recursive prediction error method (RPEM), dual extended Kalman filter (DEKF), and joint extended Kalman filter (JEKF). We compared their applicability to the estimation of coolant-void dynamic reactivity in loss-of-coolant accident in a CANDU reactor. The state equations also include the characteristics of the detector responses. The thermal hydraulic models were not included in the calculations. Two different types of detectors are considered in this analysis, the over prompt responsive Platinum detector of the reactor shutdown systems, and the under delayed responsive Vanadium detector of the flux mapping system.}, journal={Annals of Nuclear Energy}, publisher={Elsevier BV}, author={Tayebi, Lobat and Vashaee, Daryoosh}, year={2013}, month={Mar}, pages={447–457} }
@article{norouzzadeh_myles_vashaee_2013, title={Prediction of a large number of electron pockets near the band edges in type-VIII clathrate Si46and its physical properties from first principles}, volume={25}, ISSN={0953-8984 1361-648X}, url={http://dx.doi.org/10.1088/0953-8984/25/47/475502}, DOI={10.1088/0953-8984/25/47/475502}, abstractNote={The material design of type-VIII clathrate Si46 is presented based on first principles. The structural, electronic, elastic, vibrational, and thermodynamic properties of this hypothetical material are presented. Our results predict that type-VIII clathrate Si46 is an indirect semiconductor with a bandgap of 1.24 eV. The band structure revealed an interestingly large number of electron pockets near both conduction and valance band edges. Such a large density of states near the band edges, which is higher than that of the best thermoelectric materials discovered so far, can result in a large thermoelectric power factor (>0.004 W m−1 K−2) making it a promising candidate for thermoelectric applications. The elastic properties as well as the vibrational modes and the phonon state densities of this material were also calculated. Our calculations predict that the heat capacity at constant volume (isochoric) of this clathrate increases smoothly with temperature and approaches the Dulong–Petit value near room temperature. The electronic band structure shows a large number of valleys closely packed around the valance band edge, which is rare among the known semiconducting materials. These valleys can contribute to transport at high temperature resulting in a possibly high performance (ZT > 1.5) p-type thermoelectric material.}, number={47}, journal={Journal of Physics: Condensed Matter}, publisher={IOP Publishing}, author={Norouzzadeh, Payam and Myles, Charles W and Vashaee, Daryoosh}, year={2013}, month={Oct}, pages={475502} }
@article{karbasi_taheri_tayebi_razavi_vashaee_2013, title={Preparation of Al–SiC–Al2O3 metal matrix composite powder by mechanochemical reaction between Al, SiO2 and C}, volume={8}, ISSN={1750-0443}, url={http://dx.doi.org/10.1049/mnl.2013.0419}, DOI={10.1049/mnl.2013.0419}, abstractNote={In this Letter, Al–SiC–Al2O3 metal matrix nanocomposite powder was successfully synthesised employing a mechanical alloying technique, through a mechanochemical reaction among aluminium (Al), silicon dioxide (SiO2) and carbon (C). For commercial purposes, the materials (Al, SiO2 and C powders) and also the method of synthesis (mechanical alloying) is considered to be cost-effective for production of Al–SiC–Al2O3 nanocomposite. The structural evaluation of powder particles after different milling times was conducted by X-ray diffractometry, and scanning electron microscopy. The results showed that during ball milling Al, SiO2 and C reacted through a mechanochemical reaction producing Al–SiC–Al2O3 metal matrix nanocomposite powder after 50 h of ball milling and annealing at a temperature of 650°C for 1 h. The crystallite sizes of phases remained in nanometric scale.}, number={9}, journal={Micro & Nano Letters}, publisher={Institution of Engineering and Technology (IET)}, author={Karbasi, Maryam and Taheri, Mina and Tayebi, Lobat and Razavi, Mehdi and Vashaee, Daryoosh}, year={2013}, month={Sep}, pages={519–522} }
@article{salahinejad_hadianfard_macdonald_sharifi(asl)_mozafari_walker_rad_madihally_vashaee_tayebi_2013, title={Surface Modification of Stainless Steel Orthopedic Implants by Sol–Gel ZrTiO4 and ZrTiO4–PMMA Coatings}, volume={9}, ISSN={1550-7033}, url={http://dx.doi.org/10.1166/jbn.2013.1619}, DOI={10.1166/jbn.2013.1619}, abstractNote={In this paper, the biocompatibility of a medical-grade stainless steel coated with sol-gel derived, nanostructured inorganic ZrTiO4 and hybrid ZrTiO4-PMMA thin films is correlated with surface characteristics. The surfaces of the samples are characterized by atomic force microscopy, the sessile drop technique, and electrochemical corrosion experiments. The viability of adult human mesenchymal stem cells on the surfaces after one day of culture is also assessed quantitatively and morphologically. According to the results, both of the coatings improve the hydrophilicity, corrosion resistance, and thereby cytocompatibility of the substrate. Despite the higher corrosion protection by the hybrid coating, the sample coated with the inorganic thin film exhibits a better cell response, suggesting the domination of wettability. In summary, the ZrTiO4-based sol-gel films can be considered to improve the biocompatibility of metallic implants.}, number={8}, journal={Journal of Biomedical Nanotechnology}, publisher={American Scientific Publishers}, author={Salahinejad, E. and Hadianfard, M. J. and Macdonald, D. D. and Sharifi(Asl), S. and Mozafari, M. and Walker, K. J. and Rad, A. Tahmasbi and Madihally, S. V. and Vashaee, D. and Tayebi, L.}, year={2013}, month={Aug}, pages={1327–1335} }
@article{razavi_fathi_savabi_mohammad razavi_hashemi beni_vashaee_tayebi_2013, title={Surface modification of magnesium alloy implants by nanostructured bredigite coating}, volume={113}, ISSN={0167-577X}, url={http://dx.doi.org/10.1016/j.matlet.2013.09.068}, DOI={10.1016/j.matlet.2013.09.068}, abstractNote={Magnesium and its alloys have been recently investigated as biodegradable metallic biomaterials for bone implants. However, rapid corrosion rate and low bioactivity have been two limiting factors for their biomedical applications. In this work we aimed to improve these two properties for AZ91 magnesium alloy using the nanostructured bredigite (Ca7MgSi4O16) coating made by micro-arc oxidation and electrophoretic deposition methods. The results indicated that this surface treatment enhanced both corrosion resistance and the bioactivity of AZ91 substrate, making it suitable for biomedical applications.}, journal={Materials Letters}, publisher={Elsevier BV}, author={Razavi, Mehdi and Fathi, Mohammadhossein and Savabi, Omid and Mohammad Razavi, Seyed and Hashemi Beni, Batoul and Vashaee, Daryoosh and Tayebi, Lobat}, year={2013}, month={Dec}, pages={174–178} }
@article{yazdimamaghani_pourvala_motamedi_fathi_vashaee_tayebi_2013, title={Synthesis and Characterization of Encapsulated Nanosilica Particles with an Acrylic Copolymer by in Situ Emulsion Polymerization Using Thermoresponsive Nonionic Surfactant}, volume={6}, ISSN={1996-1944}, url={http://dx.doi.org/10.3390/ma6093727}, DOI={10.3390/ma6093727}, abstractNote={Nanocomposites of encapsulated silica nanoparticles were prepared by in situ emulsion polymerization of acrylate monomers. The synthesized material showed good uniformity and dispersion of the inorganic components in the base polymer, which enhances the properties of the nanocomposite material. A nonionic surfactant with lower critical solution temperature (LCST) was used to encapsulate the silica nanoparticles in the acrylic copolymer matrix. This in situ method combined the surface modification and the encapsulation in a single pot, which greatly simplified the process compared with other conventional methods requiring separate processing steps. The morphology of the encapsulated nanosilica particles was investigated by dynamic light scattering (DLS) and transmission electron microscopy (TEM), which confirmed the uniform distribution of the nanoparticles without any agglomerations. A neat copolymer was also prepared as a control sample. Both the neat copolymer and the prepared nanocomposite were characterized by Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analyses (TGA), dynamic mechanical thermal analysis (DMTA) and the flame resistance test. Due to the uniform dispersion of the non-agglomerated nanoparticles in the matrix of the polymer, TGA and flame resistance test results showed remarkably improved thermal stability. Furthermore, DMTA results demonstrated an enhanced storage modulus of the nanocomposite samples compared with that of the neat copolymer, indicating its superior mechanical properties.}, number={9}, journal={Materials}, publisher={MDPI AG}, author={Yazdimamaghani, Mostafa and Pourvala, Tannaz and Motamedi, Elaheh and Fathi, Babak and Vashaee, Daryoosh and Tayebi, Lobat}, year={2013}, month={Aug}, pages={3727–3741} }
@article{zamanipour_shi_mozafari_krasinski_tayebi_vashaee_2013, title={Synthesis, characterization, and thermoelectric properties of nanostructured bulk p-type MnSi1.73, MnSi1.75, and MnSi1.77}, volume={39}, ISSN={0272-8842}, url={http://dx.doi.org/10.1016/j.ceramint.2012.08.086}, DOI={10.1016/j.ceramint.2012.08.086}, abstractNote={P-type higher manganese silicide (HMS) has attracted considerable interest due to its remarkable thermoelectric (TE) properties and potential applications at intermediate and high temperature TE devices. In this study, a series of nanostructured bulk p-type HMS materials with different compositions of MnSix (where x=1.73, 1.75 and 1.77) were synthesized via mechanical ball milling and hot-press sintering. The X-ray diffraction analysis of the synthesized materials showed that increasing the Si contents yields to a slight shift to higher diffraction angles. The increase in Si content further resulted in a decrease in electrical conductivity and increase in Seebeck coefficient. The power factor of all three compositions are approximately identical. However, the lowest thermal conductivity was achieved in MnSi1.75 and resulted in the highest figure-of-merit among all the compositions.}, number={3}, journal={Ceramics International}, publisher={Elsevier BV}, author={Zamanipour, Zahra and Shi, Xinghua and Mozafari, Masoud and Krasinski, Jerzy S. and Tayebi, Lobat and Vashaee, Daryoosh}, year={2013}, month={Apr}, pages={2353–2358} }
@article{shabafrooz_mozafari_köhler_assefa_vashaee_tayebi_2013, title={The effect of hyaluronic acid on biofunctionality of gelatin-collagen intestine tissue engineering scaffolds}, volume={102}, ISSN={1549-3296}, url={http://dx.doi.org/10.1002/jbm.a.34984}, DOI={10.1002/jbma.34984}, abstractNote={The creation of engineered intestinal tissue has recently stimulated new endeavors with the ultimate goal of intestinal replacement for massive resections of bowel. In this context, we investigated the effect of hyaluronic acid (HA) on the physicochemical characteristics of gelatin–collagen scaffolds and its cytocompatibilty to the human intestinal epithelial Caco-2 cell line in vitro. Gelatin/collagen hybrid scaffolds with different concentrations of HA were prepared by solvent casting and freeze-drying techniques and subsequent chemical crosslinking by genipin. The morphologies of the scaffolds were characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. In vitro tests were carried out in phosphate-buffered saline (PBS) solution to study the swelling ratio and the biostability of the scaffolds. It was found that the porous structure of the scaffolds could be tailored by further addition of HA. Moreover, both the swelling ratio and the degradation rate of the scaffold increased by addition of HA. A resazurin-based cell viability assay was employed to determine the viability and estimate the number of scaffold-adherent Caco-2 cells. The assay indicated that the scaffolds were all cytocompatible. We concluded that addition of less than 15% HA to scaffolds with a composition of 9:1 gelatin:collagen results only in incremental improvement in the structural characteristics and cytocompatibility of the gelatin–collagen scaffolds. However, the scaffolds with 25% HA exhibited remarkable enhancement in physicochemical characteristics of the scaffolds including cell viability, growth, and attachment as well as their physical structure. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 3130–3139, 2014.}, number={9}, journal={Journal of Biomedical Materials Research Part A}, publisher={Wiley}, author={Shabafrooz, Vahid and Mozafari, Masoud and Köhler, Gerwald A. and Assefa, Senait and Vashaee, Daryoosh and Tayebi, Lobat}, year={2013}, month={Oct}, pages={3130–3139} }
@article{shabafrooz_mozafari_köhler_assefa_vashaee_tayebi_2013, title={The effect of hyaluronic acid on biofunctionality of gelatin-collagen intestine tissue engineering scaffolds}, volume={102}, ISSN={1549-3296}, url={http://dx.doi.org/10.1002/JBM.A.34984}, DOI={10.1002/JBM.A.34984}, abstractNote={The creation of engineered intestinal tissue has recently stimulated new endeavors with the ultimate goal of intestinal replacement for massive resections of bowel. In this context, we investigated the effect of hyaluronic acid (HA) on the physicochemical characteristics of gelatin–collagen scaffolds and its cytocompatibilty to the human intestinal epithelial Caco-2 cell line in vitro. Gelatin/collagen hybrid scaffolds with different concentrations of HA were prepared by solvent casting and freeze-drying techniques and subsequent chemical crosslinking by genipin. The morphologies of the scaffolds were characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. In vitro tests were carried out in phosphate-buffered saline (PBS) solution to study the swelling ratio and the biostability of the scaffolds. It was found that the porous structure of the scaffolds could be tailored by further addition of HA. Moreover, both the swelling ratio and the degradation rate of the scaffold increased by addition of HA. A resazurin-based cell viability assay was employed to determine the viability and estimate the number of scaffold-adherent Caco-2 cells. The assay indicated that the scaffolds were all cytocompatible. We concluded that addition of less than 15% HA to scaffolds with a composition of 9:1 gelatin:collagen results only in incremental improvement in the structural characteristics and cytocompatibility of the gelatin–collagen scaffolds. However, the scaffolds with 25% HA exhibited remarkable enhancement in physicochemical characteristics of the scaffolds including cell viability, growth, and attachment as well as their physical structure. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 3130–3139, 2014.}, number={9}, journal={Journal of Biomedical Materials Research Part A}, publisher={Wiley}, author={Shabafrooz, Vahid and Mozafari, Masoud and Köhler, Gerwald A. and Assefa, Senait and Vashaee, Daryoosh and Tayebi, Lobat}, year={2013}, month={Oct}, pages={3130–3139} }
@article{zamanipour_salahinejad_norouzzadeh_krasinski_tayebi_vashaee_2013, title={The effect of phase heterogeneity on thermoelectric properties of nanostructured silicon germanium alloy}, volume={114}, ISSN={0021-8979 1089-7550}, url={http://dx.doi.org/10.1063/1.4813474}, DOI={10.1063/1.4813474}, abstractNote={Detailed examination of the nanostructured bulk Si0.80Ge0.20 alloy synthesized by mechanical alloying and hot-press methods revealed that the alloy composition can unintentionally deviate from its nominal value. The phase deviation is difficult to be detected with x-ray diffraction due to the continuous solid solution characteristics of the Si-Ge alloy. Differential thermal analysis, in particular, showed that the synthesized nanostructured bulk Si0.80Ge0.20 alloy was a composition of two unintentional phases. The dominant phase was Si0.88Ge0.12 with admixture of Si0.58Ge0.42 in a much lower concentration. The two-phase structure is difficult to be detected in X-ray diffraction analysis and is often neglected. Thermoelectric properties of Si1−xGex significantly depend on the Ge content in the synthesized alloy. The thermoelectric properties of the synthesized material were studied experimentally and theoretically. The comparison of the data of the mixed phase nanostructured alloy with those of the single phase Si0.80Ge0.20 alloy showed enhancement in Seebeck coefficient and reduction in thermal conductivity of the former material. It was found using model calculations that these differences are due to the existence of the Si0.88Ge0.12 phase in the two-phase structure that results in the reduction of the bipolar diffusion part of the thermal conductivity and the bipolar effect in the Seebeck coefficient at high temperature. The results can stimulate a new route for enhancing the thermoelectric properties of silicon germanium alloy based on multicomponent material design.}, number={2}, journal={Journal of Applied Physics}, publisher={AIP Publishing}, author={Zamanipour, Zahra and Salahinejad, Erfan and Norouzzadeh, Payam and Krasinski, Jerzy S. and Tayebi, Lobat and Vashaee, Daryoosh}, year={2013}, month={Jul}, pages={023705} }
@article{mehrayin_farmanzad_mozafari_vashaee_tayebi_2012, title={A critical stress model for cell motility}, volume={9}, ISSN={1742-4682}, url={http://dx.doi.org/10.1186/1742-4682-9-49}, DOI={10.1186/1742-4682-9-49}, abstractNote={Abstract A detailed theoretical model that combines the conventional viscoelastic continuum description of cell motion with a dynamic active stress is presented. The model describes the ameboid cells movement comprising of protrusion and adhesion of the front edge followed by detachment and movement of the tail. Unlike the previous viscoelastic descriptions in which the cell movement is steady, the presented model describes the “walking” of the cell in response to specific active stress components acting separately on the front and rear of the cell. In this locomotive model first the tail of the cell is attached to the substrate and active stress is applied to the front of the cell. Consequently, the stress in the tail increases. When the stress in the tail exceeds a critical value, namely critical stress, the conditions are updated so that the front is fixed and the tail of the cell is detached from the substrate and moves towards the front. Consequently, the stress in the tail decreases. When the stress goes to zero, the starting conditions become active and the process continues. At start the cell is stretched and its length is increased as the front of cell migrates more than the rear. However, after several steps the front and rear move equally and the cell length stays constant during the movement. In this manuscript we analyzed such cell dynamics including the length variation and moving velocity. Finally, by considering this fact that at the single-cell level, interactions with the extracellular environment occur on a nanometer length scale, the value of critical stress was estimated.}, number={1}, journal={Theoretical Biology and Medical Modelling}, publisher={Springer Nature}, author={Mehrayin, Mehrnush and Farmanzad, Farhad and Mozafari, Masoud and Vashaee, Daryoosh and Tayebi, Lobat}, year={2012}, pages={49} }
@article{shi_zamanipour_krasinski_tree_vashaee_2012, title={An Investigation of Electrical Contacts for Higher Manganese Silicide}, volume={41}, ISSN={0361-5235 1543-186X}, url={http://dx.doi.org/10.1007/s11664-012-2149-8}, DOI={10.1007/s11664-012-2149-8}, number={9}, journal={Journal of Electronic Materials}, publisher={Springer Science and Business Media LLC}, author={Shi, Xinghua and Zamanipour, Zahra and Krasinski, Jerzy S. and Tree, Alan and Vashaee, Daryoosh}, year={2012}, month={Jun}, pages={2331–2337} }
@article{salahinejad_hadianfard_macdonald_karimi_vashaee_tayebi_2012, title={Aqueous sol–gel synthesis of zirconium titanate (ZrTiO4) nanoparticles using chloride precursors}, volume={38}, ISSN={0272-8842}, url={http://dx.doi.org/10.1016/j.ceramint.2012.04.064}, DOI={10.1016/j.ceramint.2012.04.064}, abstractNote={Zirconium titanate powders were synthesized by a straightforward sol–gel method using zirconium and titanium chlorides as metal precursors, deionized water as solvent and oxygen donor, and a NaOH solution for adjusting pH to 7. According to transmission electron microscopy, amorphous particles of nearly 5 nm in size with a relatively spherical morphology were prepared. Thermogravimetry and differential scanning calorimetery analyses on the xerogel at a heating rate of 10 °C/min indicated a crystallization temperature of 690 °C, which is comparable with previous reports. Furthermore, via differential scanning calorimetery studies using the Kissinger's equation, the activation energy for ZrTiO4 crystallization was determined to be 850 kJ/mol. Structural evaluations in the isothermal regime, using X-ray diffraction experiments, implied the onset of ZrTiO4 crystallization at 550 °C.}, number={8}, journal={Ceramics International}, publisher={Elsevier BV}, author={Salahinejad, E. and Hadianfard, M.J. and Macdonald, D.D. and Karimi, I. and Vashaee, D. and Tayebi, L.}, year={2012}, month={Dec}, pages={6145–6149} }
@article{zamanipour_vashaee_2012, title={Comparison of thermoelectric properties of p-type nanostructured bulk Si0.8Ge0.2 alloy with Si0.8Ge0.2 composites embedded with CrSi2 nano-inclusisons}, volume={112}, ISSN={0021-8979 1089-7550}, url={http://dx.doi.org/10.1063/1.4764919}, DOI={10.1063/1.4764919}, abstractNote={P-type nanostructured bulk Si0.8Ge0.2 and Si0.8Ge0.2 composites with CrSi2 nano-crystallite inclusions were synthesized via sintering approach. The composite structure showed power factor enhancement compared with nanostructured Si0.8Ge0.2 alloy. The experimental data for both structures were modeled with solving the multiband Boltzmann transport equation in the relaxation time approximation for charge carriers and phonons. The Si0.8Ge0.2 crystallite boundary scattering was modeled by a cylindrical potential barrier at the interfaces and the effects of CrSi2 nano-inclusions were modeled by spherical potential barriers in the Si0.8Ge0.2 lattice. The model calculations revealed that the enhancement in power factor is not an effect of hot carrier energy filtering, but it is due to the enhancement in charge carrier mobility in the composite structure. The analysis of charge carrier mobility components showed that while in nanostructured Si0.8Ge0.2 the ionize impurities and acoustic phonons are dominant scatterers, in the composite structure the scattering by CrSi2 nano-inclusions and acoustic phonons are dominant. The optimum size of the CrSi2 nano-inclusions for enhancing ZT was predicted with the characteristic that ZT drops rapidly when the crystallite size decreases, but it changes slowly as it is increased above its optimum value.}, number={9}, journal={Journal of Applied Physics}, publisher={AIP Publishing}, author={Zamanipour, Zahra and Vashaee, Daryoosh}, year={2012}, month={Nov}, pages={093714} }
@inbook{tayebi_nozari_vashaee_mozafari_2012, series={Current opinion in tissue engineering microscopy techniques}, title={Current opinion in tissue engineering microscopy techniques}, volume={5}, booktitle={Current microscopy contributions to advances in science and technology}, publisher={Formatex Research Center}, author={Tayebi, L. and Nozari, A. and Vashaee, D. and Mozafari, M.}, year={2012}, collection={Current opinion in tissue engineering microscopy techniques} }
@article{satyala_vashaee_2012, title={Detrimental influence of nanostructuring on the thermoelectric properties of magnesium silicide}, volume={112}, ISSN={0021-8979 1089-7550}, url={http://dx.doi.org/10.1063/1.4764872}, DOI={10.1063/1.4764872}, abstractNote={Nanostructuring techniques have steered the performance of many thermoelectric (TE) compounds towards significant improvement in performance in the last two decades. In this paper, we present a comprehensive study on the effect of bulk nanostructuring in magnesium silicide (Mg2Si) through simulation of thermoelectric properties using a multi-band semi-classical approach. It is shown that the magnitude of reduction in lattice thermal conductivity in nanostructured Mg2Si is comparable to that of reduction in charge carrier mobility for any chosen range of the grain sizes. The results are justified through a comparison with experimental data for both n-type and p-type Mg2Si characteristics versus temperature as well as doping concentration. In order to understand the underlying reasons for the detrimental effect of nanostructuring in Mg2Si, analogous calculations were performed on the well-known TE system of nanostructured Si0.8Ge0.2 and the results are compared. Model calculations show that in nanostructured Mg2Si a grain size of 20 nm results in approximately 40% reduction in lattice thermal conductivity, whereas the reduction in electrical conductivity is nearly 50% of its value in crystalline structures. For the case of nanostructured Si0.8Ge0.2, the loss in electrical conductivity was found to be a mere 20% of its magnitude in crystalline structures. The differential electrical and thermal conductivities versus charge carrier and phonon energies were calculated, respectively, and it was shown that the enhancement in Seebeck coefficient due to the energy filtering effect is also marginal. Therefore, it is conclusively shown that bulk nanostructuring in Mg2Si is not an efficient method to enhance ZT.}, number={9}, journal={Journal of Applied Physics}, publisher={AIP Publishing}, author={Satyala, Nikhil and Vashaee, Daryoosh}, year={2012}, month={Nov}, pages={093716} }
@article{mozafari_moztarzadeh_vashaee_tayebi_2012, title={Effects of heat treatment on physical, microstructural and optical characteristics of PbS luminescent nanocrystals}, volume={44}, ISSN={1386-9477}, url={http://dx.doi.org/10.1016/j.physe.2012.03.006}, DOI={10.1016/j.physe.2012.03.006}, abstractNote={Abstract The oxidation of lead sulfide (PbS) luminescent nanocrystals (NCs) considerably changes their luminescence characteristics. Hence, an understanding of the oxidation mechanism, the structure and properties of oxidized moieties is important. In this research, well-defined spherical PbS NCs were synthesized via a simple, effective and surfactant-free method and characterized. Then, the effects of heat treatment (at 250, 350, 450 and 550 °C) on the PbS NCs were investigated. The transmission electron microscope (TEM) micrographs of the synthesized PbS NCs revealed that they had a well-defined spherical morphology. In addition, the average crystallite size using Scherrer's formula was about 13 nm and the calculated lattice constant using Bragg's equation was 0.5950 nm, which was very close to the value in the standard card (JCPDS No. 5-592). Furthermore, the X-ray diffraction (XRD) revealed that the heat treatment of samples at temperatures of 250, 350,450 and 550 °C in air results in the formation of oxide sulfate phase of the compositions PbSO4 and PbO·PbSO4. The lattice parameter, crystallite size, average internal stress, micro-strain and optical properties of PbS NCs were calculated and correlated with the heat-treatment temperature.}, number={7-8}, journal={Physica E: Low-dimensional Systems and Nanostructures}, publisher={Elsevier BV}, author={Mozafari, Masoud and Moztarzadeh, Fathollah and Vashaee, Dayoosh and Tayebi, Lobat}, year={2012}, month={Apr}, pages={1429–1435} }
@inbook{mozafari_mehraien_vashaee_tayebi_2012, title={Electroconductive Nanocomposite Scaffolds: A New Strategy Into Tissue Engineering and Regenerative Medicine}, ISBN={9789535107620}, url={http://dx.doi.org/10.5772/51058}, DOI={10.5772/51058}, booktitle={Nanocomposites - New Trends and Developments}, publisher={InTech}, author={Mozafari, Masoud and Mehraien, Mehrnoush and Vashaee, Daryoosh and Tayebi, Lobat}, year={2012}, month={Sep} }
@article{dehkordi_vashaee_2012, title={Enhancement in thermoelectric power factor of polycrystalline Bi0.5Sb1.5Te3by crystallite alignment}, volume={209}, ISSN={1862-6300}, url={http://dx.doi.org/10.1002/pssa.201228147}, DOI={10.1002/pssa.201228147}, abstractNote={It is known that the random orientation of crystallites in polycrystalline Bi0.5Sb1.5Te3 reduces its thermoelectric power factor. An efficient method for growing ordered bulk polycrystalline Bi0.5Sb1.5Te3 was used and the enhancement of thermoelectric power factor was demonstrated. For comparison, samples with randomly and preferentially oriented crystallites were sintered from similar powder of Bi0.5Sb1.5Te3. A press process similar to extrusion was used to align the crystallites during the hot press. The crystallites alignment was verified by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The dominant orientation in the aligned sample was in c-plane (0,0,15). The aligned sample demonstrated significant increase in electrical conductivity while the Seebeck coefficient remained unchanged. As a result, the thermoelectric power factor of the aligned sample was improved by ∼50%.}, number={11}, journal={physica status solidi (a)}, publisher={Wiley}, author={Dehkordi, Arash Mehdizadeh and Vashaee, Daryoosh}, year={2012}, month={Jul}, pages={2131–2134} }
@article{tayebi_ma_vashaee_chen_sinha_parikh_2012, title={Long-range interlayer alignment of intralayer domains in stacked lipid bilayers}, volume={11}, ISSN={1476-1122 1476-4660}, url={http://dx.doi.org/10.1038/NMAT3451}, DOI={10.1038/NMAT3451}, number={12}, journal={Nature Materials}, publisher={Springer Nature}, author={Tayebi, Lobat and Ma, Yicong and Vashaee, Daryoosh and Chen, Gang and Sinha, Sunil K. and Parikh, Atul N.}, year={2012}, month={Oct}, pages={1074–1080} }
@article{satyala_vashaee_2012, title={Modeling of Thermoelectric Properties of Magnesium Silicide (Mg2Si)}, volume={41}, ISSN={0361-5235 1543-186X}, url={http://dx.doi.org/10.1007/s11664-012-2024-7}, DOI={10.1007/s11664-012-2024-7}, number={6}, journal={Journal of Electronic Materials}, publisher={Springer Science and Business Media LLC}, author={Satyala, Nikhil and Vashaee, Daryoosh}, year={2012}, month={Mar}, pages={1785–1791} }
@article{tayebi_mozafari_vashaee_parikh_2012, title={Structural Configuration of Myelin Figures Using Fluorescence Microscopy}, volume={2012}, ISSN={1110-662X 1687-529X}, url={http://dx.doi.org/10.1155/2012/685617}, DOI={10.1155/2012/685617}, abstractNote={Using epifluorescence microscopy, the configuration of myelin figures that are formed upon hydration of lipid stack was studied qualitatively. Little knowledge is currently available for conditions that determine the diameter of myelin figures and their degree of multilamellarity. Examining more than 300 samples, we realized that there are distinct populations of myelin figures protruding from discrete regions of lipid stack. Each population contains myelin figures with similar diameters. This indicates a direct relationship between local characteristics of parent lipid stack and the diameter of myelin figures. Evidenced by fluorescent images, we classified all the observed myelin figures into three major groups of (1) solid tubes, (2) thin tethers, and (3) hollow tubes. Solid tubes are the most common structure of myelin figures which appeared as dense shiny cylinders. Thin tethers, with long hair-shaped structure, were observed protruding from part of lipid plaque which is likely to be under tension. Hollow tubes were protruded from the parts that are unpinned from the substrate and possibly under low or no tension. The abrupt change in the configuration of myelin figures from solid tubes to hollow ones was described in a reproducible experiment where the pinned region of the parent stack became unpinned. Our observations can indicate a relation between the membrane tension of the source material and the diameter of the myelin figures.}, journal={International Journal of Photoenergy}, publisher={Hindawi Limited}, author={Tayebi, Lobat and Mozafari, Masoud and Vashaee, Daryoosh and Parikh, Atul N.}, year={2012}, pages={1–7} }
@article{satyala_vashaee_2012, title={The effect of crystallite size on thermoelectric properties of bulk nanostructured magnesium silicide (Mg2Si) compounds}, volume={100}, ISSN={0003-6951 1077-3118}, url={http://dx.doi.org/10.1063/1.3684615}, DOI={10.1063/1.3684615}, abstractNote={In nanostructured bulk materials, the additional interfaces in the material enhance phonon scattering and reduce the thermal conductivity. However, interfaces also scatter electrons and deteriorate charge carrier transport. In order to benefit from the interfacial effects, the crystallite size in the material must be small compared with phonon mean free path (PMFP) and large compared with the charge carrier mean free path (CMFP). In this paper, we solve the Boltzmann transport equation for charge carriers and phonons. We show that bulk nanostructuring of Mg2Si is not an efficient method to enhance the figure-of-merit as the PMFP and CMFP are in the same range.}, number={7}, journal={Applied Physics Letters}, publisher={AIP Publishing}, author={Satyala, Nikhil and Vashaee, Daryoosh}, year={2012}, month={Feb}, pages={073107} }
@article{norouzzadeh_zamanipour_krasinski_vashaee_2012, title={The effect of nanostructuring on thermoelectric transport properties of p-type higher manganese silicide MnSi1.73}, volume={112}, ISSN={0021-8979 1089-7550}, url={http://dx.doi.org/10.1063/1.4769884}, DOI={10.1063/1.4769884}, abstractNote={Higher manganese silicide (HMS) alloys have a complex band structure with multiple valleys close to the conduction and valence band edges, which complicates the analysis of their electronic transport properties. We present a semi-classical two-band model that can describe the charge carrier and phonon transport properties of p-type HMS in crystalline and bulk nanostructured forms. The effect of grain boundaries is modeled with an interface potential scattering for charge carriers and diffusive and refractive scattering for phonons. A unique set of effective masses and acoustic phonon deformation potentials are introduced that can explain both electrical and thermal transport properties versus temperature. The acoustic phonon and ionized impurity scatterings for charge carriers and phonon-phonon, point defect, and electronphonon scattering mechanisms for phonons are included in the model. The simplicity of the presented model would be valuable especially for practical purposes. The thermoelectric transport properties of nanostructured HMS were calculated versus grain size and it was shown that even though bulk nanostructuring of HMS enhances thermoelectric performance, it is not sufficient to enhance considerably the figure-of-merit.}, number={12}, journal={Journal of Applied Physics}, publisher={AIP Publishing}, author={Norouzzadeh, Payam and Zamanipour, Zahra and Krasinski, Jerzy S. and Vashaee, Daryoosh}, year={2012}, month={Dec}, pages={124308} }
@article{zamanipour_shi_dehkordi_krasinski_vashaee_2012, title={The effect of synthesis parameters on transport properties of nanostructured bulk thermoelectric p-type silicon germanium alloy}, volume={209}, ISSN={1862-6300}, url={http://dx.doi.org/10.1002/pssa.201228102}, DOI={10.1002/pssa.201228102}, abstractNote={Nanostructured silicon germanium thermoelectric materials prepared by mechanical alloying and sintering method have recently shown large enhancement in figure-of-merit, ZT. The fabrication of these structures often involves many parameters whose understanding and precise control is required to attain large ZT. In order to find the optimum parameters for further enhancing the ZT of this material, we have grown and studied both experimentally and theoretically different nanostructured p-type SiGe alloys. The effect of various parameters of milling process and sintering conditions on the thermoelectric properties of the grown samples were studied. The electrical and thermal properties were calculated using Boltzmann transport equation and were compared with the data of nanostructured and crystalline SiGe. It was found that the thermal conductivity not only depends on the average crystallite size in the bulk material, but also it is a strong function of alloying, porosity, and doping concentration. The Seebeck coefficient showed weak dependency on average crystallite size. The electrical conductivity changed strongly with synthesis parameters. Therefore, depending on the synthesis parameters the figure-of-merit reduced or increased by ∼60% compared with that of the crystalline SiGe. The model calculation showed that the lattice part of thermal conductivity in the nanostructured sample makes ∼80% of the total thermal conductivity. In addition, the model calculation showed that while the room temperature hole mean free path (MFP) in the nanostructured sample is dominated by the crystallite boundary scattering, at high temperature the MFP is dominated by acoustic phonon scattering. Therefore, the thermal conductivity can be further reduced by smaller crystallite size without significantly affecting the electrical conductivity in order to further enhance ZT.}, number={10}, journal={physica status solidi (a)}, publisher={Wiley}, author={Zamanipour, Zahra and Shi, Xinghua and Dehkordi, Arash M. and Krasinski, Jerzy S. and Vashaee, Daryoosh}, year={2012}, month={Jun}, pages={2049–2058} }
@article{salahinejad_hadianfard_macdonald_mozafari_vashaee_tayebi_2012, title={Zirconium titanate thin film prepared by an aqueous particulate sol–gel spin coating process using carboxymethyl cellulose as dispersant}, volume={88}, ISSN={0167-577X}, url={http://dx.doi.org/10.1016/j.matlet.2012.08.013}, DOI={10.1016/j.matlet.2012.08.013}, abstractNote={This paper deals with the preparation of ZrTiO4 thin film by a novel aqueous particulate sol–gel deposition method using carboxymethyl cellulose as dispersant. The structural characterization was performed by X-ray diffraction, transmission electron microscopy, and scanning electron microscopy. According to the results, the amorphous xerogel crystallizes to polycrystalline ZrTiO4 nanoparticles due to structural ordering conducted by calcination at 700 °C. A well-covering, crack-free, and homogeneous ZrTiO4 thin film was processed, which is attributable to the efficient role of the dispersing agent in the aqueous sol. It was also found that the outermost layer of the coating surface consists of nanoparticles with 20 nm in size.}, journal={Materials Letters}, publisher={Elsevier BV}, author={Salahinejad, E. and Hadianfard, M.J. and Macdonald, D.D. and Mozafari, M. and Vashaee, D. and Tayebi, L.}, year={2012}, month={Dec}, pages={5–8} }
@article{tayebi_vashaee_parikh_2011, title={Stability of Uni- and Multillamellar Spherical Vesicles}, volume={13}, ISSN={1439-4235}, url={http://dx.doi.org/10.1002/cphc.201100573}, DOI={10.1002/cphc.201100573}, abstractNote={Lipid molecules in water form uni- or multilamellar vesicles in polydisperse form. Herein, we present energetic considerations for their equilibrium morphological organization. Our formulation provides elemental energy diagrams, which explain the polydispersity and account for the structural diversity. These energy diagrams describe the ranges of core radius (r(c)) and number of lamellae (N) that result in the formation of stable vesicles under specific conditions, thus providing prescriptions for the design of vesicles tailored for specific properties, including stability, cargo capacity, and resistance to deformation by osmotic stress. We deduced key design criteria as follows: 1) designing highly stable unilamellar vesicles requires low bending rigidity lipids and dimensions exceeding a few hundred nm in radii; 2) very large unilamellar vesicles (r(c)>several tens of microns) are not stable for typical lipids; lipids with higher bending rigidity are required; 3) the distribution of the stable size of vesicles is proportional to the bending rigidity; 4) for the case of multilamellar vesicles, vesicles with more than a few hundred layers usually exhibit greater structural integrity than those with lower degrees of lamellarity, especially when the core radii are small (<100 nm); 5) for osmotically stressed vesicles, the energy contributed by even a small concentration gradient (>mM) is the most dominant factor in the free energy, suggesting active response by vesicles (e.g., poration) to release osmotic stress; and 6) vesicles with a core radius of a few hundred nm and more than hundred lamellae are more resistant to deformation by osmotic stress, thus making them more suited to applications involving osmotic pressure gradients, such as in drug delivery.}, number={1}, journal={ChemPhysChem}, publisher={Wiley}, author={Tayebi, Lobat and Vashaee, Daryoosh and Parikh, Atul N.}, year={2011}, month={Oct}, pages={314–322} }
@article{lee_vashaee_wang_dresselhaus_ren_chen_2010, title={Effects of nanoscale porosity on thermoelectric properties of SiGe}, volume={107}, ISSN={0021-8979 1089-7550}, url={http://dx.doi.org/10.1063/1.3388076}, DOI={10.1063/1.3388076}, abstractNote={The recent achievement of the high thermoelectric figure of merit in nanograined materials is attributed to the successful optimization of the consolidation process. Despite a thermal conductivity reduction, it has been experimentally observed that the porous nanograined materials have lower thermoelectric figure of merit than their bulk counterpart due to significant reduction in the electrical conductivity. In this paper, nanoscale porosity effects on electron and phonon transport are modeled to predict and explain thermoelectric properties in porous nanograined materials. Electron scattering at the pores is treated quantum mechanically while phonon transport is treated using a classical picture. The modeling results show that the charge carriers are scattered more severely in nanograined materials than the macroscale porous materials, due to a higher number density of scattering sites. Porous nanograined materials have enhanced Seebeck coefficient due to energy filtering effect and low thermal conductivity, which are favorable for thermoelectric applications. However, the benefit is not large enough to overcome the deficit in the electrical conductivity, so that a high sample density is necessary for nanograined SiGe.}, number={9}, journal={Journal of Applied Physics}, publisher={AIP Publishing}, author={Lee, Hohyun and Vashaee, Daryoosh and Wang, D. Z. and Dresselhaus, Mildred S. and Ren, Z. F. and Chen, Gang}, year={2010}, month={May}, pages={094308} }
@article{zhu_lee_lan_wang_joshi_wang_yang_vashaee_guilbert_pillitteri_et al._2009, title={Increased Phonon Scattering by Nanograins and Point Defects in Nanostructured Silicon with a Low Concentration of Germanium}, volume={102}, ISSN={0031-9007 1079-7114}, url={http://dx.doi.org/10.1103/physrevlett.102.196803}, DOI={10.1103/physrevlett.102.196803}, abstractNote={The mechanism for phonon scattering by nanostructures and by point defects in nanostructured silicon (Si) and the silicon germanium (Ge) alloy and their thermoelectric properties are investigated. We found that the thermal conductivity is reduced by a factor of 10 in nanostructured Si in comparison with bulk crystalline Si. However, nanosize interfaces are not as effective as point defects in scattering phonons with wavelengths shorter than 1 nm. We further found that a $5\text{ }\text{ }\mathrm{at}.\text{ }%$ Ge replacing Si is very efficient in scattering phonons shorter than 1 nm, resulting in a further thermal conductivity reduction by a factor of 2, thereby leading to a thermoelectric figure of merit 0.95 for ${\mathrm{Si}}_{95}{\mathrm{Ge}}_{5}$, similar to that of large grained ${\mathrm{Si}}_{80}{\mathrm{Ge}}_{20}$ alloys.}, number={19}, journal={Physical Review Letters}, publisher={American Physical Society (APS)}, author={Zhu, G. H. and Lee, H. and Lan, Y. C. and Wang, X. W. and Joshi, G. and Wang, D. Z. and Yang, J. and Vashaee, D. and Guilbert, H. and Pillitteri, A. and et al.}, year={2009}, month={May} }
@article{minnich_lee_wang_joshi_dresselhaus_ren_chen_vashaee_2009, title={Modeling study of thermoelectric SiGe nanocomposites}, volume={80}, ISSN={1098-0121 1550-235X}, url={http://dx.doi.org/10.1103/physrevb.80.155327}, DOI={10.1103/physrevb.80.155327}, abstractNote={Nanocomposite thermoelectric materials have attracted much attention recently due to experimental demonstrations of improved thermoelectric properties over those of the corresponding bulk material. In order to better understand the reported data and to gain insight into transport in nanocomposites, we use the Boltzmann transport equation under the relaxation-time approximation to calculate the thermoelectric properties of $n$-type and $p$-type SiGe nanocomposites. We account for the strong grain-boundary scattering mechanism in nanocomposites using phonon and electron grain-boundary scattering models. The results from this analysis are in excellent agreement with recently reported measurements for the $n$-type nanocomposite but the experimental Seebeck coefficient for the $p$-type nanocomposite is approximately 25% higher than the model's prediction. The reason for this discrepancy is not clear at the present time and warrants further investigation. Using new mobility measurements and the model, we find that dopant precipitation is an important process in both $n$-type and $p$-type nanocomposites, in contrast to bulk SiGe, where dopant precipitation is most significant only in $n$-type materials. The model also shows that the potential barrier at the grain boundary required to explain the data is several times larger than the value estimated using the Poisson equation, indicating the presence of crystal defects in the material. This suggests that an improvement in mobility is possible by reducing the number of defects or reducing the number of trapping states at the grain boundaries.}, number={15}, journal={Physical Review B}, publisher={American Physical Society (APS)}, author={Minnich, A. J. and Lee, H. and Wang, X. W. and Joshi, G. and Dresselhaus, M. S. and Ren, Z. F. and Chen, G. and Vashaee, D.}, year={2009}, month={Oct} }
@article{poudel_hao_ma_lan_minnich_yu_yan_wang_muto_vashaee_et al._2008, title={High-Thermoelectric Performance of Nanostructured Bismuth Antimony Telluride Bulk Alloys}, volume={320}, ISSN={0036-8075 1095-9203}, url={http://dx.doi.org/10.1126/science.1156446}, DOI={10.1126/science.1156446}, abstractNote={The dimensionless thermoelectric figure of merit (ZT) in bismuth antimony telluride (BiSbTe) bulk alloys has remained around 1 for more than 50 years. We show that a peak ZT of 1.4 at 100 degrees C can be achieved in a p-type nanocrystalline BiSbTe bulk alloy. These nanocrystalline bulk materials were made by hot pressing nanopowders that were ball-milled from crystalline ingots under inert conditions. Electrical transport measurements, coupled with microstructure studies and modeling, show that the ZT improvement is the result of low thermal conductivity caused by the increased phonon scattering by grain boundaries and defects. More importantly, ZT is about 1.2 at room temperature and 0.8 at 250 degrees C, which makes these materials useful for cooling and power generation. Cooling devices that use these materials have produced high-temperature differences of 86 degrees , 106 degrees , and 119 degrees C with hot-side temperatures set at 50 degrees, 100 degrees, and 150 degrees C, respectively. This discovery sets the stage for use of a new nanocomposite approach in developing high-performance low-cost bulk thermoelectric materials.}, number={5876}, journal={Science}, publisher={American Association for the Advancement of Science (AAAS)}, author={Poudel, B. and Hao, Q. and Ma, Y. and Lan, Y. and Minnich, A. and Yu, B. and Yan, X. and Wang, D. and Muto, A. and Vashaee, D. and et al.}, year={2008}, month={May}, pages={634–638} }
@article{vashaee_tayebi_luxat_2008, title={Reference model parameter identification of space–time dependent reactivity in a CANDU-PHWR}, volume={35}, ISSN={0306-4549}, url={http://dx.doi.org/10.1016/j.anucene.2007.06.021}, DOI={10.1016/j.anucene.2007.06.021}, abstractNote={Abstract The problem of estimating reactivity transients from an observed neutron flux transient is considered. This is relevant, for example, to analyzing a power rundown test or to estimating reactivity variations associated with some computer codes that do not specifically compute individual reactivity components. A method is presented which utilizes inverse space–time kinetics and optimal state estimators to extract the components of the reactivity transient from observed neutron flux measurements. The approach takes into account geometric characteristics and composition of the reactor core, as well as reactor operating conditions. Measurements from a limited number of in-core neutron flux detectors are the inputs used to extract reactivity components that fit a modal model of the reactor, referred to as the “reference model”. An improved solution for the reactivity components is then generated using the modal approximation solution for the neutron transport equation in conjunction with optimal estimation techniques. The method has been applied to a reactivity initiated accident in which a transient is initiated by a non-uniform loss-of-coolant. This results in a spatially varying neutron overpower transient that is terminated by the asymmetric insertion of shutoff rods. In this paper the Joint Extended Kalman Filter and Rauch–Tung–Striebel smoother is employed to estimate the neutron flux distribution in the core and identify the reactivity components of the reference model. The reference model in the state space and the Kalman filter algorithm are shown. Results of numerical simulations of the reactor transient and the optimal estimation of the reactivity components are presented to demonstrate the capabilities of the method.}, number={2}, journal={Annals of Nuclear Energy}, publisher={Elsevier BV}, author={Vashaee, Daryoosh and Tayebi, Lobat and Luxat, John}, year={2008}, month={Feb}, pages={228–237} }
@article{vashaee_shakouri_2007, title={Thermionic power generation at high temperatures using SiGe∕Si superlattices}, volume={101}, ISSN={0021-8979 1089-7550}, url={http://dx.doi.org/10.1063/1.2645607}, DOI={10.1063/1.2645607}, abstractNote={Recent studies have predicted that heterostructure superlattices can enhance the effective thermoelectric power factor significantly through selective emission of hot carriers via thermionic emission. Here, we study the potential of SiGe∕Si superlattices for power generation at high temperatures. A detailed theory based on Boltzmann transport equation is developed which takes into account multiple valleys. We show that thermionic emission provides only a modest improvement in the power factor. This is due to the fact that SiGe is a multivalley semiconductor and it has a large density of states. With reasonable dopings, Fermi energy in SiGe alloy is very close to the band minimum so that the symmetry of the differential conductivity does not change very much with small barrier superlattices. Particularly at high temperatures when the thermal spread of the carriers is much larger than the Fermi energy in the band, superlattice energy filtering is not effective.}, number={5}, journal={Journal of Applied Physics}, publisher={AIP Publishing}, author={Vashaee, Daryoosh and Shakouri, Ali}, year={2007}, month={Mar}, pages={053719} }
@article{vashaee_zhang_shakouri_zeng_chiu_2006, title={Cross-plane Seebeck coefficient in superlattice structures in the miniband conduction regime}, volume={74}, ISSN={1098-0121 1550-235X}, url={http://dx.doi.org/10.1103/physrevb.74.195315}, DOI={10.1103/physrevb.74.195315}, abstractNote={We have studied experimentally and theoretically the cross-plane Seebeck coefficient of short period $\mathrm{InGaAs}∕\mathrm{InAlAs}$ superlattices with doping concentrations ranging from $2\ifmmode\times\else\texttimes\fi{}{10}^{18}$ up to $3\ifmmode\times\else\texttimes\fi{}{10}^{19}\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}3}$. Measurements are performed with integrated thin film heaters in a wide temperature range of $10--300\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. It was interesting to find out that contrary to the behavior in bulk material the Seebeck coefficient did not decrease monotonically with the doping concentration. We did not observe a sign change in the Seebeck coefficient at dopings where the Fermi energy is just above a miniband. This is a sign that electrons' lateral momentum is conserved in the transport perpendicular to superlattice layers. A preliminary theory of thermoelectric transport in superlattices in the regime of miniband formation has been developed to fit the experimental results.}, number={19}, journal={Physical Review B}, publisher={American Physical Society (APS)}, author={Vashaee, Daryoosh and Zhang, Yan and Shakouri, Ali and Zeng, Gehong and Chiu, Yi-Jen}, year={2006}, month={Nov} }
@article{kim_singer_majumdar_vashaee_bian_shakouri_zeng_bowers_zide_gossard_2006, title={Cross-plane lattice and electronic thermal conductivities of ErAs:InGaAs∕InGaAlAs superlattices}, volume={88}, ISSN={0003-6951 1077-3118}, url={http://dx.doi.org/10.1063/1.2207829}, DOI={10.1063/1.2207829}, abstractNote={We studied the cross-plane lattice and electronic thermal conductivities of superlattices made of InGaAlAs and InGaAs films, with the latter containing embedded ErAs nanoparticles (denoted as ErAs:InGaAs). Measurements of total thermal conductivity at four doping levels and a theoretical analysis were used to estimate the cross-plane electronic thermal conductivity of the superlattices. The results show that the lattice and electronic thermal conductivities have marginal dependence on doping levels. This suggests that there is lateral conservation of electronic momentum during thermionic emission in the superlattices, which limits the fraction of available electrons for thermionic emission, thereby affecting the performance of thermoelectric devices.}, number={24}, journal={Applied Physics Letters}, publisher={AIP Publishing}, author={Kim, Woochul and Singer, Suzanne L. and Majumdar, Arun and Vashaee, Daryoosh and Bian, Zhixi and Shakouri, Ali and Zeng, Gehong and Bowers, John E. and Zide, Joshua M. O. and Gossard, Arthur C.}, year={2006}, month={Jun}, pages={242107} }
@article{zide_vashaee_bian_zeng_bowers_shakouri_gossard_2006, title={Demonstration of electron filtering to increase the Seebeck coefficient in In0.53Ga0.47As∕In0.53Ga0.28Al0.19As superlattices}, volume={74}, ISSN={1098-0121 1550-235X}, url={http://dx.doi.org/10.1103/physrevb.74.205335}, DOI={10.1103/physrevb.74.205335}, abstractNote={In this paper, we explore electron filtering as a technique to increase the Seebeck coefficient and the thermoelectric power factor of heterostructured materials over that of the bulk. We present a theoretical model in which the Seebeck coefficient and the power factor can be increased in an ${\mathrm{In}}_{0.53}{\mathrm{Ga}}_{0.47}\mathrm{As}$-based composite material. Experimental measurements of the cross-plane Seebeck coefficient are presented and confirm the importance of the electron filtering technique to decouple the electrical conductivity and Seebeck coefficient to increase the thermoelectric power factor.}, number={20}, journal={Physical Review B}, publisher={American Physical Society (APS)}, author={Zide, J. M. O. and Vashaee, D. and Bian, Z. X. and Zeng, G. and Bowers, J. E. and Shakouri, A. and Gossard, A. C.}, year={2006}, month={Nov}, pages={205335} }
@article{vashaee_shakouri_goldberger_kuykendall_pauzauskie_yang_2006, title={Electrostatics of nanowire transistors with triangular cross sections}, volume={99}, ISSN={0021-8979 1089-7550}, url={http://dx.doi.org/10.1063/1.2168229}, DOI={10.1063/1.2168229}, abstractNote={The electrostatic properties of nanowire field effect transistors with triangular cross sections were investigated. The Poisson equation was solved for these structures; furthermore, two properties of the nanowire field effect transistors, the gate capacitance and current versus gate voltage, were calculated. The simulation results yielded the type, mobility, and concentration of the carriers, as well as the Ohmic contact resistance of the wire transistor. We examined how wire capacitance depends on various parameters: wire diameter, gate oxide thickness, charge density, and shape. It is shown that the capacitance of a triangular nanowire is less than that of a cylindrical nanowire of the same size, which could be significant in structures with thin gate oxides. The simulation results were compared with the previously reported experimental data on GaN nanowires.}, number={5}, journal={Journal of Applied Physics}, publisher={AIP Publishing}, author={Vashaee, Daryoosh and Shakouri, Ali and Goldberger, Joshua and Kuykendall, Tevye and Pauzauskie, Peter and Yang, Peidong}, year={2006}, month={Mar}, pages={054310} }
@article{vashaee_shakouri_2006, title={HgCdTe superlattices for solid-state cryogenic refrigeration}, volume={88}, ISSN={0003-6951 1077-3118}, url={http://dx.doi.org/10.1063/1.2191094}, DOI={10.1063/1.2191094}, abstractNote={A tall barrier superlattice structure based on mercury cadmium telluride material system is proposed that can achieve a large effective thermoelectric figure of merit (ZTmax∼3) at cryogenic temperatures. Calculations based on the Boltzmann transport equation taking into account the quantum mechanical electron transmission show that the Seebeck coefficient can be increased significantly at low temperatures with the use of nonplanar barriers as the thermal spreading of the electron density is tightened around the Fermi level. This provides a better asymmetric differential conductivity around the Fermi level close to the top of the barrier. Consequently, a high thermoelectric power factor is produced resulting in a large ZT.}, number={13}, journal={Applied Physics Letters}, publisher={AIP Publishing}, author={Vashaee, Daryoosh and Shakouri, Ali}, year={2006}, month={Mar}, pages={132110} }
@article{vashaee_christofferson_zhang_shakouri_zeng_labounty_fan_piprek_bowers_croke_2005, title={Modeling and optimization of single-element bulk SiGe thin-film coolers}, volume={9}, ISSN={1089-3954 1091-7640}, url={http://dx.doi.org/10.1080/10893950590913459}, DOI={10.1080/10893950590913459}, abstractNote={Abstract Modeling and optimization of bulk SiGe thin-film coolers are described. Thin-film coolers can provide large cooling power densities compared to commercial thermoelectrics. Thin-film SiGe coolers have been demonstrated with maximum cooling of 4°C at room temperature and with cooling power density exceeding 500 W/cm2. Important parameters in the design of such coolers are investigated theoretically and are compared with experimental data. Thermoelectric cooling, joule heating, and heat conduction are included in the model as well as non-ideal effects such as contact resistance, geometrical effects, and three-dimensional thermal and electrical spreading resistance of the substrate. Simulations exhibit good agreement with experimental results for bulk Si and SiGe thin-film coolers. It turned out that in many spot cooling applications using two n- and p-elements electrically in series and thermally in parallel does not give significant improvement over single leg elements. This is in contrast to conventional thermoelectric modules and is due to the aspect ratio and special geometry of thin film coolers. With optimization of SiGe thin-film cooler, simulations predict it can provide over 16°C with cooling power density of over 2000 W/cm2.}, number={1}, journal={Microscale Thermophysical Engineering}, publisher={Informa UK Limited}, author={Vashaee, Daryoosh and Christofferson, James and Zhang, Yan and Shakouri, Ali and Zeng, Gehong and LaBounty, Chris and Fan, Xiaofeng and Piprek, Joachim and Bowers, John E. and Croke, Edward}, year={2005}, month={Feb}, pages={99–118} }
@article{zide_klenov_stemmer_gossard_zeng_bowers_vashaee_shakouri_2005, title={Thermoelectric power factor in semiconductors with buried epitaxial semimetallic nanoparticles}, volume={87}, ISSN={0003-6951 1077-3118}, url={http://dx.doi.org/10.1063/1.2043241}, DOI={10.1063/1.2043241}, abstractNote={We have grown composite epitaxial materials that consist of semimetallic ErAs nanoparticles embedded in a semiconducting In0.53Ga0.47As matrix both as superlattices and randomly distributed throughout the matrix. The presence of these particles increases the free electron concentration in the material while providing scattering centers for phonons. We measure electron concentration, mobility, and Seebeck coefficient of these materials and discuss their potential for use in thermoelectric power generators.}, number={11}, journal={Applied Physics Letters}, publisher={AIP Publishing}, author={Zide, J. M. and Klenov, D. O. and Stemmer, S. and Gossard, A. C. and Zeng, G. and Bowers, J. E. and Vashaee, D. and Shakouri, A.}, year={2005}, month={Sep}, pages={112102} }
@article{vashaee_shakouri_2004, title={Electronic and thermoelectric transport in semiconductor and metallic superlattices}, volume={95}, ISSN={0021-8979 1089-7550}, url={http://dx.doi.org/10.1063/1.1635992}, DOI={10.1063/1.1635992}, abstractNote={A detailed theory of nonisothermal electron transport perpendicular to multilayer superlattice structures is presented. The current–voltage (I–V) characteristics and the cooling power density are calculated using Fermi–Dirac statistics, density-of-states for a finite quantum well and the quantum mechanical reflection coefficient. The resulting equations are valid in a wide range of temperatures and electric fields. It is shown that conservation of lateral momentum plays an important role in the device characteristics. If the lateral momentum of the hot electrons is conserved in the thermionic emission process, only carriers with sufficiently large kinetic energy perpendicular to the barrier can pass over it and cool the emitter junction. However, if there is no conservation of lateral momentum, the number of electrons participating in a thermionic emission will increase. This has a significant effect on the I–V measurements as well as the cooling characteristics. Theoretical calculations are compared with the experimental dark current characteristics of quantum well infrared photodetectors and good agreement over a wide temperature range for a variety of superlattice structures is obtained. In contrast with earlier studies, it is shown that lateral momentum is conserved for the case of electron transport in planar semiconductor barriers.}, number={3}, journal={Journal of Applied Physics}, publisher={AIP Publishing}, author={Vashaee, Daryoosh and Shakouri, Ali}, year={2004}, month={Feb}, pages={1233–1245} }
@article{vashaee_shakouri_2004, title={Improved Thermoelectric Power Factor in Metal-Based Superlattices}, volume={92}, ISSN={0031-9007 1079-7114}, url={http://dx.doi.org/10.1103/physrevlett.92.106103}, DOI={10.1103/physrevlett.92.106103}, abstractNote={In this paper we present a detailed theory of electron and thermoelectric transport perpendicular to heterostructure superlattices. This nonlinear transport regime above barriers is also called heterostructure thermionic emission. We show that metal-based superlattices with tall barriers can achieve a large effective thermoelectric figure of merit (ZT > 5 at room temperature). A key parameter to achieving high performance is the nonconservation of lateral momentum during the thermionic emission process. Conservation of lateral momentum is a consequence of translational symmetry in the plane of the superlattice. We also discuss the use of nonplanar barriers and embedded quantum dot structures to achieve high thermoelectric conversion efficiency.}, number={10}, journal={Physical Review Letters}, publisher={American Physical Society (APS)}, author={Vashaee, Daryoosh and Shakouri, Ali}, year={2004}, month={Mar} }
@article{vashaee_shakouri_2004, title={Nonequilibrium electrons and phonons in thin film thermionic coolers}, volume={8}, ISSN={1089-3954 1091-7640}, url={http://dx.doi.org/10.1080/10893950490445225}, DOI={10.1080/10893950490445225}, abstractNote={The effect of hot carriers on the cooling performance of single barrier heterostructure thermionic coolers is studied theoretically. By studying nonequilibrium characteristics of electrons and phonons in the device, fundamental limitation in the cooler performance is analyzed. In particular, we investigated the effect of various boundary conditions at heterojunctions on the electron and phonon temperature distributions. These boundary conditions have a strong impact on the device operation. Thin film devices under high voltage or in high current density are examples of situations where electrons and phonons are not in equilibrium and a coupled transport equation should be solved for an accurate analysis. In a thermoelectric/thermionic device one measures the lattice temperature while cooling occurs in the electron gas. Although at low currents electrons and phonons have the same equilibrium temperature, by increasing the current they may have different temperatures, which can lead to a reduction in cooling power density. We will show that in materials with faster electron energy relaxation, that is, higher electron-phonon coupling, thermionic cooling performance is less affected by high current injection and that recently demonstrated SiGe thin film coolers are not limited by hot carrier effects.}, number={2}, journal={Microscale Thermophysical Engineering}, publisher={Informa UK Limited}, author={Vashaee, Daryoosh and Shakouri, Ali}, year={2004}, pages={91–100} }
@article{fan_zeng_croke_labounty_ahn_vashaee_shakouri_bowers_2001, title={High cooling power density SiGe/Si micro-coolers}, volume={37}, ISSN={0013-5194}, url={http://dx.doi.org/10.1049/el:20010096}, DOI={10.1049/el:20010096}, abstractNote={SiGe/Si superlattice micro-coolers are investigated experimentally. They can be monolithically integrated with Si-based microelectronic devices to achieve localised cooling and temperature control. Cooling by as much as 4.2 K at 25°C and 12 K at 200°C was measured on 3 µm thick, 60 × 60 µm2 devices. This corresponds to maximum cooling power densities approaching kW/cm2.}, number={2}, journal={Electronics Letters}, publisher={Institution of Engineering and Technology (IET)}, author={Fan, X. and Zeng, G. and Croke, E. and LaBounty, C. and Ahn, C.C. and Vashaee, D. and Shakouri, A. and Bowers, J.E.}, year={2001}, pages={126} }
@article{rastegaria_salahinejad_e._s._n._a._l._vashaee, title={Non-hydrolytic sol-gel processing of chloride precursors loaded at forsterite stoichiometry}, journal={Journal of Alloys and Compounds}, author={Rastegaria, S. O. and Salahinejad, K. and E., Fadavi and S., Eftekhari and N., Nozariasbmarz and A., Tayebi and L. and Vashaee, D.} }
@article{norouzzadeh_vashaee, title={The Effect of multivalley bandstructure on thermoelectric properties of Al (x) Ga1-x As (vol 44, pg 636, 2015)}, volume={45}, number={6}, journal={Journal of Electronic Materials}, author={Norouzzadeh, P. and Vashaee, D.}, pages={3249–3250} }