@article{tendulkar_mirmalek-sani_childers_saul_opara_ramasubramanian_2012, title={A three-dimensional microfluidic approach to scaling up microencapsulation of cells}, volume={14}, number={3}, journal={Biomedical Microdevices}, author={Tendulkar, S. and Mirmalek-Sani, S. H. and Childers, C. and Saul, J. and Opara, E. C. and Ramasubramanian, M. K.}, year={2012}, pages={461–469} }
 @article{ramasubramanian_venditti_gillella_2012, title={Sensor systems for high-speed intelligent sorting of waste paper in recycling}, volume={11}, number={2}, journal={TAPPI Journal}, author={Ramasubramanian, M. K. and Venditti, R. A. and Gillella, P. K.}, year={2012}, pages={33–39} }
 @inproceedings{tendulkar_mcquilling_childers_pareta_opara_ramasubramanian_2011, title={A Scalable microfluidic device for the mass production of microencapsulated islets}, volume={43}, number={9}, booktitle={Transplantation Proceedings}, author={Tendulkar, S. and McQuilling, J. P. and Childers, C. and Pareta, R. and Opara, E. C. and Ramasubramanian, M. K.}, year={2011}, pages={3184–3187} }
 @article{ramasubramanian_sun_chen_2011, title={A mechanics of materials model for the creping process}, volume={133}, number={5}, journal={Journal of Manufacturing Science and Engineering}, author={Ramasubramanian, M. K. and Sun, Z. H. and Chen, G.}, year={2011} }
 @article{ramasubramanian_shiffler_jayachandran_2010, title={A computational fluid dynamics modeling and experimental study of the mixing process for dispersion of synthetic fibers in wet-lay forming}, volume={9}, number={3}, journal={TAPPI Journal}, author={Ramasubramanian, M. K. and Shiffler, D. A. and Jayachandran, A.}, year={2010}, pages={6–13} }
 @article{ramasubramanian_tiruthani_2009, title={A Capacitive Displacement Sensing Technique for Early Detection of Unbalanced Loads in a Washing Machine}, volume={9}, ISSN={["1424-8220"]}, DOI={10.3390/s91209559}, abstractNote={Horizontal axis washing machines are water and energy efficient and becoming popular in the USA. Unlike a vertical axis washer, these do not have an agitator and depend solely on tumbling for the agitation of laundry during the wash cycle. However, due to the constant shifting of laundry during washing, the load distribution is often unbalanced during the high speed spin cycle. We present a displacement-based sensing method to detect unbalance early while the spin rate (rpm) is well below the resonance frequency so that corrective actions may be taken prior to the high speed spin cycle. Experimental and analytical characterizations of the sensor configuration are presented. Results show that the displacement sensor is more appropriate than an accelerometer for this application and offer the potential for a simple, reliable, low cost detection of unbalance.}, number={12}, journal={SENSORS}, author={Ramasubramanian, Melur K. and Tiruthani, Karthik}, year={2009}, month={Dec}, pages={9559–9571} }
 @article{ramasubramanian_alexander_2009, title={An integrated fiberoptic-microfluidic device for agglutination detection and blood typing}, volume={11}, ISSN={["1572-8781"]}, DOI={10.1007/s10544-008-9227-y}, abstractNote={In this paper, an integrated fiberoptic-microfluidic device for the detection of agglutination for blood type cross-matching has been described. The device consists of a straight microfluidic channel through with a reacted RBC suspension is pumped with the help of a syringe pump. The flow intersects an optical path created by an emitter-received fiber optic pair integrated into the microfluidic device. A 650 nm laser diode is used as the light source and a silicon photodiode is used to detect the light intensity. The spacing between the tips of the two optic fibers can be adjusted. When fiber spacing is large and the concentration of the suspension is high, scattering phenomenon becomes the dominant mechanism for agglutination detection while at low concentrations and small spacing, optointerruption becomes the dominant mechanism. An agglutination strength factor (ASF) is calculated from the data. Studies with a variety of blood types indicate that the sensing method correctly identifies the agglutination reaction in all cases. A disposable integrated device can be designed for future implementation of the method for near-bedside pre-transfusion check.}, number={1}, journal={BIOMEDICAL MICRODEVICES}, author={Ramasubramanian, Melur K. and Alexander, Stewart P.}, year={2009}, month={Feb}, pages={217–229} }
 @article{ramasubramanian_shiffler_jayachandran_2008, title={A Computational fluid dynamics modeling and experimental study of the mixing process for the dispersion of the synthetic fibers in wet-lay forming}, volume={3}, number={1}, journal={Journal of Engineered Fibers and Fabrics}, author={Ramasubramanian, M. K. and Shiffler, D. A. and Jayachandran, A.}, year={2008}, pages={11–19} }
 @article{katuri_asrani_ramasubramanian_2008, title={Intraocular pressure monitoring sensors}, volume={8}, ISSN={["1558-1748"]}, DOI={10.1109/JSEN.2007.912539}, abstractNote={Continuous measurement of intraocular pressure is important in the detection and treatment of glaucoma. While a point check of intraocular pressure in a doctor's office using indirect measurements such as the tonometer is helpful, it is inadequate to track circadian variation. Circadian variation is an independent risk factor in addition to elevated pressure levels. This paper is aimed at providing an up-to-date review of various intraocular pressure sensing techniques and in vivo sensor design approaches. The basic operating principles of various implantable sensors are reviewed and categorized into groups to delineate their differences. A discussion is presented identifying the drawbacks of existing designs and key design questions are proposed for future progress.}, number={1-2}, journal={IEEE SENSORS JOURNAL}, author={Katuri, Kalyan C. and Asrani, Sanjay and Ramasubramanian, Melur K.}, year={2008}, pages={12–19} }
 @article{ramasubramanian_barham_swaminathan_2008, title={Mechanics of a mosquito bite with applications to microneedle design}, volume={3}, number={4}, journal={Bioinspiration & Biomimetics}, author={Ramasubramanian, M. K. and Barham, O. M. and Swaminathan, V.}, year={2008} }
 @article{ramasubramanian_anthony_lambert_2008, title={Simplified spectra photometric method for the detection of red blood cell agglutination}, volume={47}, ISSN={["2155-3165"]}, DOI={10.1364/AO.47.004094}, abstractNote={Human error is the most significant factor attributed to incompatible blood transfusions. A spectrophotometric approach to blood typing has been developed by examining the spectral slopes of dilute red blood cell (RBC) suspensions in saline, in the presence and absence of various antibodies, offering a technique for the quantitative determination of agglutination intensity [Transfusion39, 1051, 1999TRANAT0041-113210.1046/j.1537-2995.1999.39101051.x]. We offer direct theoretical prediction of the observed change in slope in the 660-1000 nm range through the use of the T-matrix approach and Lorenz-Mie theory for light scattering by dilute RBC suspensions. Following a numerical simulation using the T-matrix code, we present a simplified sensing method for detecting agglutination. The sensor design has been prototyped, fully characterized, and evaluated through a complete set of tests with over 60 RBC samples and compared with the full spectrophotometric method. The LED and photodiode pairs are found to successfully reproduce the spectroscopic determination of red blood cell agglutination.}, number={22}, journal={APPLIED OPTICS}, author={Ramasubramanian, Melur and Anthony, Steven and Lambert, Jeremy}, year={2008}, month={Aug}, pages={4094–4105} }
 @article{ramasubramanian_wang_2007, title={A computational micromechanics constitutive model for the unloading behavior of paper}, volume={44}, ISSN={["1879-2146"]}, DOI={10.1016/j.ijsolstr.2007.05.002}, abstractNote={In this study, a computational micromechanics material model for the unloading behavior of paper and other nonwoven materials is presented. The asymptotic fiber and bond (AFB) model for paper elastic–plastic behavior [Sinha, S.K., Perkins, R.W., 1995. Micromechanics constitutive model for use in finite element analysis, In: Proceedings of the 1995, Joint ASME Applied Mechanics and Materials Summer Meeting, Los Angeles, CA, USA, Jun 28–30, 1995] has been extended to model the unloading process through a computational algorithm and implemented using the UMAT subroutine in ABAQUS finite element code. For every unloading increment, the material model assumes elastic unloading with a slope equal to the initial elastic modulus. The Jacobian matrix of the constitutive model is updated at every unloading increment by applying the incremental form of AFB model for a planar element with an elastic fiber and bond condition. A uniaxial tensile and a biaxial Mullen burst loading–unloading experiments were carried out for a paperboard sample and simulated using the model. The stress–strain curve and residual strain for the uniaxial loading were in good agreement with experimental results. The finite element model of the burst test with the AFB unloading material model predicted the general shape of the pressure versus deflection curve. However, the model over predicted the residual deflection by more than 50%. The loading portion of the pressure–deflection curve had a significant offset from experimental curves, and the nonlinearity in the unloading curve towards the end was not predicted. The discrepancies with experimental results are attributed to the burst test itself, model parameter estimation inadequacies, boundary conditions used in the FEA, and neglecting time-dependant effects. Nevertheless, the model can be useful in parametric studies relating microstructure to unloading behavior in structural problems.}, number={22-23}, journal={INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES}, author={Ramasubramanian, M. K. and Wang, Yun}, year={2007}, month={Nov}, pages={7615–7632} }
 @article{ramasubramanian_venditti_katuri_2007, title={A noncontact sensor for the identification of paper and board samples on a high speed sorting conveyor}, volume={60}, number={5}, journal={Appita Journal}, author={Ramasubramanian, M. K. and Venditti, R. A. and Katuri, K. C.}, year={2007}, month={Sep}, pages={366–371} }
 @article{ramasubramanian_venditti_katuri_2007, title={Behavior of paper on a high speed conveyor subjected to air jet impingement: a method for estimating bending stiffness}, volume={2}, ISSN={["1559-3959"]}, DOI={10.2140/jomms.2007.2.201}, abstractNote={Stiffness based sorting of mixed paper waste at high speed is desirable for sorting board, cardstock, and paper from each other for efficient recycling. We propose a quick, non-contact method for measuring the relative stiffness of paper samples moving on a conveyor at high speeds. The method consists of impinging an air jet on a moving paper sample while it is crossing a gap during transfer from one conveyor belt to another. The deflection caused by the impinging air jet can be measured and used to categorize different grades of paper. In this paper, we report results from a simulation of the proposed method using a finite element model. Influence of conveyor speed, sample orientation and nozzle pressure is studied using the model. Results indicate that the stiffness estimation has sufficient resolution to distinguish between board and paper grades at high conveyor speeds.}, number={2}, journal={Journal of Mechanics of Materials and Structures}, author={Ramasubramanian, M.K. and Venditti, R.A. and Katuri, K.C.}, year={2007}, pages={201–219} }
 @article{uner_ramasubramanian_zauscher_kadla_2006, title={Adhesion interactions between poly(vinyl alcohol) and iron-oxide surfaces: The effect of acetylation}, volume={99}, ISSN={["1097-4628"]}, DOI={10.1002/app.22980}, abstractNote={Abstract}, number={6}, journal={JOURNAL OF APPLIED POLYMER SCIENCE}, author={Uner, B and Ramasubramanian, MK and Zauscher, S and Kadla, JF}, year={2006}, month={Mar}, pages={3528–3534} }
 @article{ramasubramanian_madanshetty_suwan-acksorn_2006, title={Characterization of focused high frequency ultrasonic, removal of thermally fused toner from paper surfaces - an experimental study}, volume={59}, number={4}, journal={Appita Journal}, author={Ramasubramanian, M. K. and Madanshetty, S. I. and Suwan-Acksorn, P.}, year={2006}, pages={306-} }
 @article{ramasubramanian_jackson_2005, title={A sensor for measurement of friction coefficient on moving flexible surfaces}, volume={5}, ISSN={["1558-1748"]}, DOI={10.1109/JSEN.2005.845205}, abstractNote={Measurement of coefficient of friction between surfaces is of interest in numerous engineering applications. Although laboratory tests of material samples in tribological systems are used to measure the friction coefficient, on-line friction measurement on newly manufactured surfaces, or between two interacting surfaces of interest, is nonexistent. In this paper, we describe a new sensor, called the tribosensor, that accomplishes real-time friction coefficient measurement between materials, where one of the two materials in the tribological pair is being processed or manufactured at high speeds, such as in paper, plastics, aluminum, and other flexible materials. This paper discusses the operating principle of the sensor, design configuration, and performance characterization. Comparison with traditional off-line laboratory measurements is also presented.}, number={5}, journal={IEEE SENSORS JOURNAL}, author={Ramasubramanian, MK and Jackson, SD}, year={2005}, month={Oct}, pages={844–849} }
 @article{ramasubramanian_venditti_ammineni_mallapragada_2005, title={Optical sensor for noncontact measurement of lignin content in high-speed moving paper surfaces}, volume={5}, ISSN={1530-437X}, url={http://dx.doi.org/10.1109/JSEN.2005.851007}, DOI={10.1109/JSEN.2005.851007}, abstractNote={An optical sensor for real-time measurement of lignin content in moving paper sheets is described in this paper. The sensor is useful for high-speed automated sorting of papers according to lignin content in a mixed-waste stream for efficient recycling. The sensor measures lignin fluorescence when excited in the visible region. Results indicate that when paper surfaces are excited with a laser source (532 nm), the lignin fluorescence spectrum shows a peak near 650 nm. Measurement of this peak intensity from paper samples is a measure of lignin content and correlates linearly with the standard chemical method for lignin determination (Klasson lignin content). Newsprint samples, typically containing high lignin, produce high intensity, while ledger printing and writing grades with low lignin content produce low-fluorescence intensity. The proposed sensor configuration is discussed and results from a systematic study of variables, namely, text printed on surface, homogeneous dyed in color, printed color patches, paper thickness, sensor configuration parameters such as excitation source intensity, and distance from sample surface are reported. In dynamic tests on a simulated conveyor operating at realistic speeds, the sensor is able to reliably measure fluorescence intensities on unprinted samples without ambiguity and identify high and low lignin-containing samples.}, number={5}, journal={IEEE Sensors Journal}, publisher={Institute of Electrical and Electronics Engineers (IEEE)}, author={Ramasubramanian, M.K. and Venditti, R.A. and Ammineni, C. and Mallapragada, V.}, year={2005}, month={Oct}, pages={1132–1139} }
 @article{ramasubramanian_muthuraman_2003, title={A computational mechanics model for the brim forming process in paperboard container manufacturing}, volume={125}, ISSN={["1087-1357"]}, DOI={10.1115/1.1580527}, abstractNote={The manufacturing process of brim forming in paperboard containers consists of taking a thin paperboard shell and forming a brim to provide additional stiffness to the structure. A paper cup is an example of such a structure manufactured at rates exceeding 300 units per minute. A realistic model for the manufacturing process is not available and the effects of process and material parameters are not well understood. In this study, a finite element model of this highly nonlinear problem is presented. The model takes into account the material orthotropy and nonlinear elastic-plastic behavior, die paperboard contact interaction during loading and unloading, and friction between the metal die and paperboard, die geometry, and environmental conditions. Model predictions of the force-displacement curve agree well with the experimentally observed results.}, number={3}, journal={JOURNAL OF MANUFACTURING SCIENCE AND ENGINEERING-TRANSACTIONS OF THE ASME}, author={Ramasubramanian, MK and Muthuraman, K}, year={2003}, month={Aug}, pages={476–483} }
 @article{ramasubramanian_noori_lee_2003, title={Evolution of mechatronics into a graduate degree program in the United States: The NC State University master of science program with mechatronics concentration}, volume={19}, number={4}, journal={International Journal of Engineering Education}, author={Ramasubramanian, M. K. and Noori, M. N. and Lee, G. K.}, year={2003}, pages={519–524} }
 @article{ramasubramanian_swecker_2001, title={Mechanics of brim forming in paperboard containers - An experimental investigation}, volume={27}, number={4}, journal={Journal of Pulp and Paper Science}, author={Ramasubramanian, M. K. and Swecker, M. D.}, year={2001}, pages={113–117} }
 @article{ramasubramanian_shmagin_2000, title={An experimental investigation of the creping process in low-density paper manufacturing}, volume={122}, ISSN={["1087-1357"]}, DOI={10.1115/1.1285908}, abstractNote={In this paper, a unique apparatus for the laboratory simulation and analysis of the creping process is described. The device consists of a fluid-heated micro-yankee dryer, 25.4 cm (10 inches) in diameter, and 8.25 cm (3.25 inches) wide, and a creping blade engaging system mounted on a three-component piezoelectric load cell. Mechatronics design principles were followed to design the device so that discrete paper samples can be creped at speeds over 250 meters/minute. The device has been used to study the effect of various manufacturing process parameters such as the creping adhesive type, concentration (application rate), creping geometry (creping angle), machine speed, and moisture content in the sheet at the time of creping, and their influence on sheet structure and creping forces. A mechanistic description of the creping process is also presented. [S1087-1357(00)02102-X]}, number={3}, journal={JOURNAL OF MANUFACTURING SCIENCE AND ENGINEERING-TRANSACTIONS OF THE ASME}, author={Ramasubramanian, MK and Shmagin, DL}, year={2000}, month={Aug}, pages={576–581} }
 @article{davis_singletary_srinivasarao_knoff_ramasubramanian_2000, title={Microstructure organization in para-aramid fibers}, volume={70}, ISSN={["0040-5175"]}, DOI={10.1177/004051750007001102}, abstractNote={ The existence of "lateral birefringence," i.e., the difference between the refractive index for light polarized parallel to the fiber radius and light polarized perpendicular to the radius in the cross-sectional plane, combined with the existence of electron diffraction contrast "bands" in longitudinal fiber sections has led to work appearing to indicate that para-aramid fibers, in particular poly(para-phenylene terephthalamide), have an almost crystallographically perfect orthotropic structure in which the hydrogen bonds are all parallel to fiber radii. Optical path difference profiles, calculated based on the proposed orthotropic structure, are in reasonable qualitative agreement with interference microscope data. Quantitatively, however, the orthotropic structure is only partially developed based on published values of the principle refractive indices. Furthermore, the degree to which this structure is developed varies with distance from the fiber axis in some fibers' types. }, number={11}, journal={TEXTILE RESEARCH JOURNAL}, author={Davis, H and Singletary, J and Srinivasarao, M and Knoff, W and Ramasubramanian, MK}, year={2000}, month={Nov}, pages={945–950} }
 @article{singletary_davis_ramasubramanian_knoff_toney_2000, title={The transverse compression of PPTA fibers - Part I - Single fiber transverse compression testing}, volume={35}, ISSN={["0022-2461"]}, DOI={10.1023/A:1004764024568}, number={3}, journal={JOURNAL OF MATERIALS SCIENCE}, author={Singletary, J and Davis, H and Ramasubramanian, MK and Knoff, W and Toney, M}, year={2000}, month={Feb}, pages={573–581} }
 @article{singletary_davis_song_ramasubramanian_knoff_2000, title={The transverse compression of PPTA fibers - Part II - Fiber transverse structure}, volume={35}, ISSN={["1573-4803"]}, DOI={10.1023/A:1004716108638}, number={3}, journal={JOURNAL OF MATERIALS SCIENCE}, author={Singletary, J and Davis, H and Song, Y and Ramasubramanian, MK and Knoff, W}, year={2000}, month={Feb}, pages={583–592} }
 @article{ramasubramanian_crews_1998, title={Shear strength of an adhesively bonded paper-metal interface}, volume={24}, number={1}, journal={Journal of Pulp and Paper Science}, author={Ramasubramanian, M. K. and Crews, W. R.}, year={1998}, pages={31–36} }