@article{tang_kumar_alavi_sandeep_2012, title={Recent advances in biopolymers and biopolymer-based nanocomposites for food packaging materials}, volume={52}, DOI={10.1080/10408398.2010.500508}, abstractNote={Plastic packaging for food and non-food applications is non-biodegradable, and also uses up valuable and scarce non-renewable resources like petroleum. With the current focus on exploring alternatives to petroleum and emphasis on reduced environmental impact, research is increasingly being directed at development of biodegradable food packaging from biopolymer-based materials. The proposed paper will present a review of recent developments in biopolymer-based food packaging materials including natural biopolymers (such as starches and proteins), synthetic biopolymers (such as poly lactic acid), biopolymer blends, and nanocomposites based on natural and synthetic biopolymers. The paper will discuss the various techniques that have been used for developing cost-effective biodegradable packaging materials with optimum mechanical strength and oxygen and moisture barrier properties. This is a timely review as there has been a recent renewed interest in research studies, both in the industry and academia, towards development of a new generation of biopolymer-based food packaging materials with possible applications in other areas.}, number={5}, journal={CRC Critical Reviews in Food Science and Nutrition}, author={Tang, X. Z. and Kumar, P. and Alavi, S. and Sandeep, KP}, year={2012}, pages={426–442} }
 @misc{kumar_sandeep_alavi_truong_2011, title={A Review of Experimental and Modeling Techniques to Determine Properties of Biopolymer-Based Nanocomposites}, volume={76}, ISSN={["1750-3841"]}, DOI={10.1111/j.1750-3841.2010.01919.x}, abstractNote={Abstract: The nonbiodegradable and nonrenewable nature of plastic packaging has led to a renewed interest in packaging materials based on bio‐nanocomposites (biopolymer matrix reinforced with nanoparticles such as layered silicates). One of the reasons for unique properties of bio‐nanocomposites is the difference in physics at nanoscale as compared to that at macroscale. Therefore, the effect of nanoscale on the properties of bio‐nanocomposites is discussed. Properties of bio‐nanocomposites are governed by the extent of dispersion of nanoparticles in the biopolymer matrix and interaction between nanoparticles and the biopolymer. Selection of proper technique to determine properties of these bio‐nanocomposites is very critical in assessing their performance. Experimental techniques (tensile testing, barrier property measurement, dynamic mechanical analysis, differential scanning calorimetry, thermogravimetric analysis, rheological measurement) to determine the mechanical, barrier, thermal, and rheological properties of bio‐nanocomposites are discussed in terms of methodology, interpretation of results, and application in studying the properties of bio‐nanocomposites. Mathematical modeling plays an important role in predicting the properties of bio‐nanocomposites and comparing them to the measured properties. This comparison helps in better understanding the mechanism for much improved properties of bio‐nanocomposites. Mathematical modeling is also helpful in understanding the effects of different parameters on the properties of bio‐nanocomposites. Therefore, the article describes mathematical modeling of mechanical and barrier properties of bio‐nanocomposites using analytical micromechanics.}, number={1}, journal={JOURNAL OF FOOD SCIENCE}, author={Kumar, P. and Sandeep, K. P. and Alavi, S. and Truong, V. D.}, year={2011}, pages={E2–E14} }
 @article{kumar_sandeep_alavi_truong_gorga_2010, title={Preparation and characterization of bio-nanocomposite films based on soy protein isolate and montmorillonite using melt extrusion}, volume={100}, ISSN={["1873-5770"]}, DOI={10.1016/j.jfoodeng.2010.04.035}, abstractNote={The non-biodegradable and non-renewable nature of plastic packaging has led to a renewed interest in packaging materials based on bio-nanocomposites (biopolymer matrix reinforced with nanoparticles such as layered silicates). Bio-nanocomposite films based on soy protein isolate (SPI) and montmorillonite (MMT) were prepared using melt extrusion. Effects of the pH of film forming solution, MMT content, and extrusion processing parameters (screw speed and barrel temperature distribution) on the structure and properties of SPI–MMT bio-nanocomposite films were investigated. X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) were used for structural characterization of the films. Properties of the films were determined by tensile testing, dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA), and water vapor barrier measurement. The arrangement of MMT in the soy protein matrix ranged from exfoliated at lower MMT content (5%) to intercalated at higher MMT content (15%). There was a significant improvement in mechanical (tensile strength and percent elongation at break) and dynamic mechanical properties (glass transition temperature and storage modulus), thermal stability, and water vapor permeability of the films with the addition of MMT. The results presented in this study show the feasibility of using bio-nanocomposite technology to improve the properties of biopolymer films based on SPI.}, number={3}, journal={JOURNAL OF FOOD ENGINEERING}, author={Kumar, P. and Sandeep, K. P. and Alavi, S. and Truong, V. D. and Gorga, R. E.}, year={2010}, month={Oct}, pages={480–489} }
 @article{steed_truong_simunovic_sandeep_kumar_cartwright_swartzel_2008, title={Continuous Flow Microwave-Assisted Processing and Aseptic Packaging of Purple-Fleshed Sweetpotato Purees}, volume={73}, ISSN={["1750-3841"]}, DOI={10.1111/j.1750-3841.2008.00950.x}, abstractNote={ABSTRACT:  Pumpable purees from purple‐flesh sweetpotatoes (PFSP) were subjected to microwave heating using a 60 kW, 915 MHz continuous flow system, followed by aseptic packaging in flexible containers to obtain a shelf‐stable product. Initial test runs were conducted using a 5 kW 915 MHz microwave system to measure dielectric in‐line properties and examine the puree temperature profiles. The results demonstrated uniformity in heating of the puree at sterilization temperatures (>121 °C), and the dielectric constants and loss factors were within the range of published values for orange‐fleshed sweetpotato purees. The pilot‐scale test runs in a 60 kW microwave unit produced shelf‐stable puree packages stable at room temperature. Polyphenolic content of the PFSP purees were evaluated and the results showed that while total phenolics increased (5.9%) and total monomeric anthocyanins slightly decreased (14.5%) with microwave application, antioxidant activity determined by 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging activity and oxygen radical absorbance capacity (ORAC) assays did not significantly change as a result of microwave processing. Color values showed that microwave‐processed samples differed from fresh puree in saturation and hue angle, but not in overall color change. PFSP purees increased in gel strength when microwave processed, packaged, and stored, but the gel could be easily disrupted into flowable purees. Overall, high‐quality retention can be obtained by microwave processing and aseptic packaging of PFSP purees so that they can be used as functional food ingredients.}, number={9}, journal={JOURNAL OF FOOD SCIENCE}, author={Steed, L. E. and Truong, V. -D. and Simunovic, J. and Sandeep, K. P. and Kumar, P. and Cartwright, G. D. and Swartzel, K. R.}, year={2008}, pages={E455–E462} }
 @article{coronel_simunovic_sandeep_kumar_2008, title={Dielectric properties of pumpable food materials at 915 MHz}, volume={11}, ISSN={["1094-2912"]}, DOI={10.1080/10942910701472755}, abstractNote={Dielectric properties of pumpable food materials having a potential to be processed using a continuous flow microwave heating system were measured at 915 MHz and in the temperature range of 10–90°C. The products considered in this study were milk and dairy products (ϵ′: 70.0 to 50.8 and ϵ″: 14.7 to 41.3), ready to eat puddings (ϵ′: 69.4 to 52.1 and ϵ″: 17.2 to 23.8), soy beverages (ϵ′: 75.4 to 60.8 and ϵ″: 9.0 to 19.8), and avocado products (ϵ′: 51.6 to 39.0 and ϵ″: 17.7 to 67.5). The results showed that the dielectric constant decreased with an increase in temperature and the dielectric loss factor increased with an increase in temperature. Polynomial correlations for the dependence of dielectric properties on temperature were developed. The dielectric properties measured in this study are important parameters for designing a continuous flow microwave heating system for processing pumpable food materials.}, number={3}, journal={INTERNATIONAL JOURNAL OF FOOD PROPERTIES}, author={Coronel, P. and Simunovic, J. and Sandeep, K. P. and Kumar, P.}, year={2008}, pages={508–518} }
 @article{kumar_coronel_truong_simunovic_swartzel_sandeep_cartwright_2008, title={Overcoming issues associated with the scale-up of a continuous flow microwave system for aseptic processing of vegetable purees}, volume={41}, ISSN={["1873-7145"]}, DOI={10.1016/j.foodres.2007.11.004}, abstractNote={Continuous flow microwave heating is a promising alternative to conventional heating for aseptic processing of low-acid vegetable purees. However, non-uniform temperature distribution and control of processing parameters are the major hurdles in the implementation of continuous flow microwave heating. This study was undertaken to overcome issues associated with the scale-up of a continuous flow microwave system from pilot plant scale to industrial scale and to conduct extended run times of 8 h based on the procedure developed. Dielectric properties and cross-sectional temperature profiles were measured during processing of green pea puree and carrot puree from 20 to 130 °C in a 5-kW continuous flow microwave system. During processing of green peas, cross-sectional temperature differences of 8.6 and 5 °C were observed at the outlet for center temperatures of 50 and 130 °C respectively. These temperature differences were 32.9 and 3.6 °C for carrot puree. For process scale-up, green pea puree and carrot puree were processed in a 60-kW microwave system with the objective of successful operation for at least 8 h. Static mixers, installed at the exit of each of the microwave applicators, improved temperature uniformity for both purees. Successful completion of processing the purees for 8 h in the 60-kW microwave system showed the potential for the scale-up of a continuous flow microwave system from pilot plant scale to industrial scale.}, number={5}, journal={FOOD RESEARCH INTERNATIONAL}, author={Kumar, P. and Coronel, P. and Truong, V. D. and Simunovic, J. and Swartzel, K. R. and Sandeep, K. P. and Cartwright, G.}, year={2008}, pages={454–461} }
 @article{coronel_simunovic_sandeep_cartwright_kumar_2008, title={Sterilization solutions for aseptic processing using a continuous flow microwave system}, volume={85}, ISSN={["0260-8774"]}, DOI={10.1016/j.jfoodeng.2007.08.016}, abstractNote={The conventional method of sterilization of an aseptic processing system by recirculating hot water cannot be applied to a continuous flow microwave heating system. Therefore, a model solution with dielectric and flow properties similar to that of the food product is required as a sterilization solution. Dielectric properties of solutions of table salt, sugar, CMC, and mixtures of these solutes were measured and correlations for the dependence of dielectric properties on concentration of solute and temperature were developed. Sterilization solutions were prepared by matching the dielectric and rheological properties of solutions prepared from table salt, sugar, and CMC to those of the food product to be processed. Dielectric properties of milk and sweet potato puree were compared to those of salt–sugar–CMC mixtures and a model solution that closely matched the properties of each product was prepared and experimentally tested in a 5 kW continuous flow microwave system operating at 915 MHz. The temperature profile at the exit of the heating section during heating of the sterilization solution was compared to the temperature profile during heating of the product. It was observed that the temperatures during transition from sterilization solution to the product did not change appreciably. Thus, these model solutions can be used as sterilization solutions for aseptic processing using a continuous flow microwave system.}, number={4}, journal={JOURNAL OF FOOD ENGINEERING}, author={Coronel, P. and Simunovic, J. and Sandeep, K. P. and Cartwright, G. D. and Kumar, P.}, year={2008}, month={Apr}, pages={528–536} }
 @article{kumar_coronel_simunovic_sandeep_2008, title={Thermophysical and dielectric properties of salsa con queso and its vegetable ingredients at sterilization temperatures}, volume={11}, ISSN={["1532-2386"]}, DOI={10.1080/10942910701272312}, abstractNote={Aseptic processing of a low-acid multiphase food product using continuous flow microwave heating system can combine the advantages of an aseptic process along with those of microwave heating. The objective of this study was to determine the thermophysical and dielectric properties of salsa con queso and its vegetable ingredients (tomatoes, bell peppers, jalapeno peppers, and onions) at a temperature range of 20 to 130°C to design a safe process for aseptic processing of salsa con queso using a continuous flow microwave system. The influence of temperature on apparent viscosity of salsa con queso was described by an Arrhenius-type relationship. Second order polynomial correlations for the dependence of thermophysical and dielectric properties (at 915 MHz) of salsa con queso and its vegetable ingredients on temperature were developed. The results showed that the dielectric constant decreased with an increase in temperature and the dielectric loss factor increased with an increase in temperature.}, number={1}, journal={INTERNATIONAL JOURNAL OF FOOD PROPERTIES}, author={Kumar, Prabhat and Coronel, Pablo and Simunovic, Josip and Sandeep, K. P.}, year={2008}, pages={112–126} }
 @article{kumar_coronel_simunovic_sandeep_2007, title={Feasibility of aseptic processing of a low-acid multiphase food product (salsa con queso) using a continuous flow microwave system}, volume={72}, ISSN={["1750-3841"]}, DOI={10.1111/j.1750-3841.2007.00306.x}, abstractNote={ABSTRACT:  Aseptic processing of a low‐acid multiphase food product using a continuous flow microwave heating system can combine the advantages of an aseptic process along with those of microwave heating. Dielectric properties of 2 different brands of 1 such product (salsa con queso) were measured under continuous flow conditions at a temperature range of 20 to 130 °C. At 915 MHz, the dielectric constant ranged from 58.7 at 20 °C to 41.3 at 130 °C with dielectric loss factor ranging from 41.0 at 20°C to 145.5 at 130 °C. The loss tangent at 915 MHz ranged from 0.61 at 20 °C to 3.52 at 130 °C. The temperature profiles at the outlet during processing of salsa con queso in a 5‐kW microwave unit showed a narrow temperature distribution between the center and the wall of the tube. The study showed the feasibility of aseptic processing of salsa con queso using a continuous flow microwave system.}, number={3}, journal={JOURNAL OF FOOD SCIENCE}, author={Kumar, P. and Coronel, P. and Simunovic, J. and Sandeep, K. P.}, year={2007}, month={Apr}, pages={E121–E124} }
 @article{brinley_stam_truong_coronel_kumar_simunovic_sandeep_cartwright_swartzel_jaykus_et al._2007, title={Feasibility of utilizing bioindicators for testing microbial inactivation in sweetpotato purees processed with a continuous-flow microwave system}, volume={72}, ISSN={["0022-1147"]}, DOI={10.1111/j.1750-3841.2007.00371.x}, abstractNote={ABSTRACT:  Continuous‐flow microwave heating has potential in aseptic processing of various food products, including purees from sweetpotatoes and other vegetables. Establishing the feasibility of a new processing technology for achieving commercial sterility requires evaluating microbial inactivation. This study aimed to assess the feasibility of using commercially available plastic pouches of bioindicators containing spores of Geobacillius stearothermophilus ATCC 7953 and Bacillus subtilis ATCC 35021 for evaluating the degree of microbial inactivation achieved in vegetable purees processed in a continuous‐flow microwave heating unit. Sweetpotato puree seeded with the bioindicators was subjected to 3 levels of processing based on the fastest particles: undertarget process (F0 approximately 0.65), target process (F0 approximately 2.8), and overtarget process (F0 approximately 10.10). After initial experiments, we found it was necessary to engineer a setup with 2 removable tubes connected to the continuous‐flow microwave system to facilitate the injection of indicators into the unit without interrupting the puree flow. Using this approach, 60% of the indicators injected into the system could be recovered postprocess. Spore survival after processing, as evaluated by use of growth indicator dyes and standard plating methods, verified inactivation of the spores in sweetpotato puree. The log reduction results for B. subtilis were equivalent to the predesigned degrees of sterilization (F0). This study presents the first report suggesting that bioindicators such as the flexible, food‐grade plastic pouches can be used for microbial validation of commercial sterilization in aseptic processing of foods using a continuous‐flow microwave system.}, number={5}, journal={JOURNAL OF FOOD SCIENCE}, author={Brinley, T. A. and Stam, C. N. and Truong, V. D. and Coronel, P. and Kumar, P. and Simunovic, J. and Sandeep, K. P. and Cartwright, G. D. and Swartzel, K. R. and Jaykus, L. A. and et al.}, year={2007}, pages={E235–E242} }
 @article{kumar_coronel_simunovic_truong_sandeep_2007, title={Measurement of dielectric properties of pumpable food materials under static and continuous flow conditions}, volume={72}, ISSN={["0022-1147"]}, DOI={10.1111/j.1750-3841.2007.00315.x}, abstractNote={ABSTRACT:  Continuous flow microwave sterilization is an emerging technology that has the potential to replace the conventional heating processes for viscous and pumpable food products. Dielectric properties of pumpable food products were measured by a new approach (under continuous flow conditions) at a temperature range of 20 to 130 °C and compared with those measured by the conventional approach (under static conditions). The food products chosen for this study were skim milk, green pea puree, carrot puree, and salsa con queso. Second‐order polynomial correlations for the dependence of dielectric properties at 915 MHz of the food products on temperature were developed. Dielectric properties measured under static and continuous flow conditions were similar for homogeneous food products such as skim milk and vegetable puree, but they were significantly different for salsa con queso, which is a multiphase food product. The results from this study suggest that, for a multiphase product, dielectric properties measured under continuous flow conditions should be used for designing a continuous flow microwave heating system.}, number={4}, journal={JOURNAL OF FOOD SCIENCE}, author={Kumar, P. and Coronel, P. and Simunovic, J. and Truong, V. D. and Sandeep, K. P.}, year={2007}, month={May}, pages={E177–E183} }
 @misc{suman_kumar_2006, title={A survey of simulated annealing as a tool for single and multiobjective optimization}, volume={57}, number={10}, journal={Journal of the Operational Research Society}, author={Suman, B. and Kumar, P.}, year={2006}, pages={1143–1160} }
 @article{narayan_bhosle_tiwari_gupta_kumar_wu_2006, title={Methods for processing tantalum films of controlled microstructures and properties}, volume={24}, ISSN={["0734-2101"]}, DOI={10.1116/1.2335863}, abstractNote={The authors have fabricated thin films of alpha tantalum (α-Ta) with crystalline and amorphous structures by nonequilibrium pulsed laser deposition techniques, and compared their electrical properties and diffusion characteristics with those of polycrystalline beta tantalum (β-Ta) films produced by magnetron sputtering. The microstructure and atomic structure of these films were studied by x-ray diffraction and high-resolution electron microscopy, while elemental analysis was performed using electron energy-loss spectroscopy and x-ray dispersive analysis. The α-Ta with body-centered-cubic structure was formed only under clean, impurity-free conditions of laser molecular beam epitaxy. The resistivity measurements in the temperature range of 10–300K showed room-temperature values to be 15–30μΩcm for α-Ta, 180–200μΩcm for β-Ta, and 250–275μΩcm for amorphous tentalum (a-Ta). The temperature coefficients of resistivity (TCRs) for α-Ta and β-Ta were found to be positive with characteristic metallic behavior, while TCR for a-Ta was negative, characteristic of high-resistivity disordered metals. The authors discuss the mechanism of formation of a-Ta and show that it is stable in the temperature range of 650–700°C. Electron energy-loss spectroscopy (EELS) and Rutherford backscattering measurements showed oxygen content in a-Ta films to be less than 0.1%. The secondary ion mass spectrometry, scanning transmission electron microscope Z-contrast imaging, and EELS studies show that, after 650°C annealing for 1h, a-Ta films have less than 10nm Cu diffusion distance while polycrystalline Ta films have substantial Cu diffusion. The superior diffusion barrier properties of a-Ta for Cu metallization have been attributed to the lack of grain boundaries which usually lead to enhanced diffusion in the case of polycrystalline α-Ta and β-Ta films. Thus, superior diffusion properties of a-Ta provide an optimum solution for copper metallization in next-generation silicon microelectronic devices.}, number={5}, journal={JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A}, author={Narayan, J. and Bhosle, V. and Tiwari, A. and Gupta, A. and Kumar, P. and Wu, R.}, year={2006}, pages={1948–1954} }
 @article{suman_kumar_2005, title={An analytical model for fluid flow and heat transfer in a micro-heat pipe of polygonal shape}, volume={48}, ISSN={["1879-2189"]}, DOI={10.1016/j.ijheatmasstransfer.2005.05.001}, abstractNote={An analytical model for fluid flow and heat transfer in a micro-heat pipe of polygonal shape is presented by utilizing a macroscopic approach. The coupled nonlinear governing equations for fluid flow, heat and mass transfer have been modified and have been solved analytically. The analytical model enables us to study the performance and the limitations of such a device and provides the analytical expressions for critical heat input, dry-out length and available capillary head for the flow of fluid. A dimensionless parameter, which plays an important role in predicting the performance of a micro-heat pipe, is obtained from the analytical model. The results predicted by the model compared with the published results in literature and good agreement has been obtained. The general and analytical nature of the simple model will have its applicability in the design of micro-heat pipes.}, number={21-22}, journal={INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER}, author={Suman, B and Kumar, P}, year={2005}, month={Oct}, pages={4498–4509} }