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Title: Evaluating antimicrobial efficacy of GS-2 on reusable food packaging materials
Creator: Birje, Nupoor Prasad
Date: 2024
Description: Packaging plays an important role in maintaining the quality and safety of fresh produce throughout storage, transportation and end-use by...
Show morePackaging plays an important role in maintaining the quality and safety of fresh produce throughout storage, transportation and end-use by consumers. Single-use packaging poses several environmental impacts; therefore use of reusable packaging is being encouraged in the fresh produce supply chain. However, the utilization of harmful chemicals and inadequate sanitation standards limit the reuse of packaging materials. To overcome these limitations, this study focuses on testing a non-toxic, water-soluble antimicrobial; GS-2 coating to facilitate the reuse of food packaging and reduce the risk of microbial contamination. In this study, the antimicrobial activity of GS-2 was evaluated against foodborne pathogens; Escherichia coli, Listeria monocytogenes and Salmonella enterica on plastic and cardboard coupons at 1 h and 15 min treatment times and 0.3%, 1% and 3% concentration. These coupons were also stored at 4℃ and 90% R.H. and 18℃ and 45% R.H. inoculated on different days up to 42 d with E. coli or L. monocytogenes to study retention of activity of GS-2. Additionally, the efficacy of GS-2 to reduce transfer of bacteria from cardboard and plastic to tomato was investigated. The initial level of inoculum was 9 log CFU/surface for all experiments. Cardboard and plastic without GS-2 were used to compare the reduction of bacteria on the treated surfaces. The differences in the population of bacteria were evaluated using Student’s T-Test and ANOVA; p <0.05 was considered significant. With 3% GS-2 concentration on plastic, there was > 4.50 log CFU/surface reduction of all three bacteria in 1 h. There was a lower reduction of the population on cardboard as compared to plastic for all bacteria, the reduction obtained was 1.83, 2.65 and 3.42 log CFU/surface for E. coli, L. monocytogenes and S. enterica, respectively, in 1 h. There was no significant difference between 15 min and 1 h treatments for cardboard. Further, the highest reduction of bacteria was obtained with 3% GS-2 on plastic. For cardboard, no significant difference in population reduction was obtained for E. coli or S. enterica, with 1% or 3% GS-2. However, for L. monocytogenes there was a higher reduction with 3%. GS-2 remained active on the surface of plastic and cardboard for a period of six weeks. For cardboard, there was a lower reduction of bacteria and there was no trend in the population reduction from 0 to 42 d, with the populations remaining within a range of 4-5 log CFU/surface. There was a significant transfer of E. coli or L. monocytogenes from plastic surfaces without GS-2 to tomato at 5-6 log CFU/tomato. However, the transfer of bacteria from the GS-2-coated plastic to the tomato was below the limit of enumeration. For cardboard, the population was below the limit of enumeration, irrespective of the GS-2 coating. Based on the results, GS-2 is a promising antimicrobial that reduces the microbial load on packaging surfaces and prevents cross-contamination of fresh produce. The retention of GS-2 activity makes it suitable for reusable packaging applications.
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Title: Modeling and Optimization of Embedded Active Flow Control Systems
Creator: Henry, James M.
Date: 2024
Description: This thesis presents research focused on the aerodynamic performance of circulation control on two-dimensional and quasi-two-dimensional wings...
Show moreThis thesis presents research focused on the aerodynamic performance of circulation control on two-dimensional and quasi-two-dimensional wings. Aerodynamic loads, namely lift, drag, and moment coefficients, are measured through Reynolds Averaged Navier Stokes (RANS) modeling and wind tunnel experiment. A simplified and parameterized RANS model is presented as a rapidly iterable approach to estimating the performance of trailing-edge circulation control on two dimensional airfoils, with the hypothesis that an optimized airfoil shape can be found which maximizes the lift coefficient increment generated by circulation control, through modification of the wing profile. The simplified modeling setup is compared with more conventional approaches to numerical simulation of circulation control. The performance of the simplified modeling scheme is then compared with wind tunnel studies, for both steady-state and dynamic performance, as functions of both momentum coefficient dCμ and chord-based Reynolds number Re_c. The dynamic performance for the model is studied to find an analog to the theoretical unsteady models of Wagner and Theodorsen. An adjoint optimization framework is used to find an optimal airfoil profile for circulation control. The optimized profile is then compared in both a simulation and a wind tunnel test study against a NACA0015 airfoil. In simulation, improvement between 12% and 15% is seen for the lift control authority for all values of dCμ and Re_c tested. In experiment, the optimized profile demonstrated improvements of up to 28% in lift control authority, dCL/dCμfor values of Cμ, and decreased performance for higher values of Cμ.
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Title: DEVELOPMENT OF A MODIFIED LUBRICATED SQUEEZING FLOW TECHNIQUE FOR GENERATING EQUIBIAXIAL ELONGATIONAL FLOWS IN POLYMER MELTS
Creator: Kashyap, Teresita
Date: 2011-04-19, 2011-05
Description: Techniques for measuring the equibiaxial extensional properties of materials are rather scarce, in part due to the difficulty to generate...
Show moreTechniques for measuring the equibiaxial extensional properties of materials are rather scarce, in part due to the difficulty to generate homogeneous flow. The two more acknowledged techniques are rotating clamps and lubricated squeezing flow (LSF). The rotating clamps technique employs the MultiAxiale Dehnung (MAD) rheometer, and data from this method are considered to be the most reliable for equibiaxial extensional flow. Unfortunately, the MAD device does not further exist. The LSF technique, where a sample is deformed by compression between parallel lubricated plates, fails at small deformations due to loss of lubrication. The objectives of this study were to develop a novel experimental technique called continuous lubricated squeezing flow (CLSF), and to study the rheological behavior of polymer melts and other viscous fluids in equibiaxial elongational deformations. The parameters that may affect results from the LSF technique were examined for constant strain rate and step-strain flows. The performance of the LSF method was evaluated in constant strain-rate deformations by direct comparisons of viscosity data from the MAD device. The CLSF technique was developed and validated, also in constant strain-rate deformations, by direct comparison of rheological data from the MAD rheometer. The CLSF technique was used to investigate the equibiaxial extensional flow behavior of monodisperse polystyrene melts. The relaxation modulus for a linear and a branched polymer melt was measured by LSF technique, and time-strain factorability was analyzed. Damping functions were calculated and compared with the tube, slip-link and pom-pom models. The results from this study showed that transient viscosity data from LSF technique are higher than those from the MAD device, and are independent of the polymer and experimental conditions. The behavior exhibited by the LSF data could easily be mistaken for the phenomenon of strain hardening. The new CLSF technique resolved the lubricant thinning problem in LSF. The measured viscosity from CLSF was in excellent agreement with the MAD data, thus, meaningful equibiaxial elongational flow information could be obtained by CLSF technique. The equibiaxial behavior of monodisperse polystyrene melts was linear. The LSF method could successfully be used for step-strain deformations. Time-strain factorability of the relaxation modulus was observed for a linear and a branched melt. Damping function data for the linear polymer showed good agreement with the tube and slip-link models. The relaxation modulus and the damping function of the branched polymer showed significant differences from the pom-pom model predictions.
Ph.D. in Chemical Engineering, May 2011
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Title: INVESTIGATION OF ANISOTROPIC THERMAL TRANSPORT IN CROSS-LINKED POLYMERS
Creator: Simavilla, David Nieto
Date: 2014, 2014-07
Description: Thermal transport in lightly cross-linked polyisoprene and polybutadine subjected to uniaxial elongation is investigated experimentally. We...
Show moreThermal transport in lightly cross-linked polyisoprene and polybutadine subjected to uniaxial elongation is investigated experimentally. We employ two experimental techniques to assess the e↵ect that deformation has on this class of materials. The first technique, which is based on Forced Rayleigh Scattering (FRS), allows us to measure the two independent components of the thermal di↵usivity tensor as a function of deformation. These measurements along with independent measurements of the tensile stress and birefringence are used to evaluate the stress-thermal and stress-optic rules. The stress-thermal rule is found to be valid for the entire range of elongations applied. In contrast, the stress-optic rule fails for moderate to large stretch ratios. This suggests that the degree of anisotropy in thermal conductivity depends on both orientation and tension in polymer chain segments. The second technique, which is based on infrared thermography (IRT), allows us to measure anisotropy in thermal conductivity and strain induced changes in heat capacity. We validate this method measurements of anisotropic thermal conductivity by comparing them with those obtained using FRS. We find excellent agreement between the two techniques. Uncertainty in the infrared thermography method measurements is estimated to be about 2-5 %. The accuracy of the method and its potential application to non-transparent materials makes it a good alternative to extend current research on anisotropic thermal transport in polymeric materials. A second IRT application allows us to investigate the dependence of heat capacity on deformation. We find that heat capacity increases with stretch ratio in polyisoprene specimens under uniaxial extension. The deviation from the equilibrium value of heat capacity is consistent with an independent set of experiments comparing anisotropy in thermal di↵usivity and conductivity employing FRS and IRT techniques. We identify finite extensibility and strain-induced crystallization as the possible causes explaining our observations and evaluate their contribution making use of classical rubber elasticity results. Finally, we study of the role of evaporation-induced thermal e↵ects in the wellknow phenomena of the tears of wine. We develop a transport model and support its predictions by experimentally measuring the temperature gradient present in wine and cognac films using IRT. Our results demonstrate that the Marangoni flow responsible for wine tears results from both composition and temperature gradients, whose relative contribution strongly depends on the thermodynamic properties of ethanol-water mixtures. The methods developed here can be used to obtain a deeper understanding of Marangoni flows, which are ubiquitous in nature and modern technology.
Ph.D. in Chemical Engineering, July 2014
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Title: CONNECTIONS BETWEEN FINE ART AND SCIENTIFIC ILLUSTRATIONS IN THE PTRS IN THE PERIOD 1660-1850
Creator: O'donnell, Kathryn E.
Date: 2013, 2013-05
Description: This dissertation investigates connections between scientific illustration in the Philosophical Transactions of the Royal Society (PTRS) and...
Show moreThis dissertation investigates connections between scientific illustration in the Philosophical Transactions of the Royal Society (PTRS) and fine art in the period from 1660 to 1850, comparing three science illustrations from approximately 100-year intervals, 1667, 1775, and 1839, with fine art images of Van Dyck, (1641), Wilson, (1774), and Constable, (1831). My assessment consisted of an objective visual analysis of the science and fine art images using Wolfflin’s comparison pairs, an analysis of the compositional and external art influences in the science images, and an evaluation of the science images related to period art theory. My research found that the science images do reflect period fine art elements, to a degree, but they are not expressive statements of fine art. My research revealed increasing aesthetic influences in the scientific images from 1667 to 1839, suggesting that the incorporation of fine art elements in these science images, and the increased use of illustrations in PTRS articles, may reflect a growing awareness of the significance of images in scientific argument.
PH.D in Technical Communication, May 2013
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Title: A Practical Network Coding Scheme Over GF (2q) for Multi-User Cooperative Wireless Networks
Creator: Chang, Peiqiang
Date: 2011-04-21, 2011-05
Description: In this work, I present a non-binary Decode-and-Forward Network Coded (DFNC) protocol over GF(2q) for reliable communication in multi-user...
Show moreIn this work, I present a non-binary Decode-and-Forward Network Coded (DFNC) protocol over GF(2q) for reliable communication in multi-user cooperative wireless networks. There are two time phases in DFNC protocol: each user transmits its own data in the first time phase and serves as a relay in the second time phase to transmit the network coded information combining its own and others. In particular, a non-binary coding matrix construction method is proposed so as to reduce the transmission overhead and to provide independence for decoding. Moreover, we design a creative joint decoding algorithm: Credit-based Updating Algorithm (CUA), which works on symbol-level coupling network-decoding and channel-decoding together. By fully exploiting the spatial diversity and redundancy residing in network coding, CUA improves the solvability of decoding set at the destination, and therefore achieves better performance than traditional decoding algorithms, such as Gaussian Elimination. From the analysis and simulation results, we demonstrate that the proposed protocol achieves higher diversity order and outperforms other traditional transmission schemes in terms of Symbol Error Rate (SER).
M.S. in Computer Engineering, May 2011
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Title: Thermal Resistance of Listeria Monocytogenes At Low Water Activity: Effect of Humectants
Creator: Wang, Peng
Date: 2012-04-25, 2012-05
Description: The thermal resistance of L. monocytogenes Scott A was examined in glycerol solutions, sucrose solutions, and peanut butters at different...
Show moreThe thermal resistance of L. monocytogenes Scott A was examined in glycerol solutions, sucrose solutions, and peanut butters at different water activities (aw) from 0.27-0.99. The analysis of D-values in glycerol and sucrose solutions shown L. monocytogenes has greater thermal resistance in sucrose solutions at each same water activity level (0.85 and 0.80). The calculated D-values were 13.80 ± 0.31, 6.38 ± 0.73, 3.02 ± 0.10 min in sucrose solution (aw = 0.80), and 9.39 ± 0.22, 4.86 ± 0.29, 2.40 ± 0.19 min in sucrose solution (aw = 0.85), compared to D-values of 1.20 ± 0.04, 0.36 ± 0.03, 0.12 ± 0.01 sec in glycerol solution (aw = 0.80), and 9.60 ± 0.20, 4.20 ± 0.26, 1.80 ± 0.10 sec in glycerol solution (aw = 0.85) at 72, 75 and 78◦C. In each menstrum the thermal resistance of Listeria increased significantly as compared to phosphate buffer. However, the comparison of D-values in glycerol and sucrose solutions failed to reflect a linear relationship between water activities and thermal resistance of L. monocytogenes. In peanut butter samples, the D-values were 16.53 ± 0.31, 9.06 ± 0.75, 7.13 ± 0.27 min and 35.36 ± 2.14, 23.10 ± 1.31, 17.73 ± 1.96 min for 3.13% and 9.38% sugar concentration respectively at temperatures of 80, 90, 100◦C. The Z-values were 56.08 ± 4.87◦C and 67.18 ± 8.44◦C in peanut butter with 9.38% and 3.13% sugar concentration. These results indicate increases of thermal resistance of Listeria with increased sugar concentration in a pure solution. The same protection effect of sugar did not appear to play a role in much increased thermal resistance of Listeria in peanut butter.
M.S. in Food Safety and Technology
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Title: SIMULTANEOUS INJECTION OF STABLE AND RADIOACTIVE IONS INTO UPGRADED MULTI-USER ATLAS
Creator: Perry, Amichay
Date: 2015, 2015-12
Description: Argonne Tandem Linac Accelerator System (ATLAS) is a Department of Energy (DOE) national user research facility, located at Argonne National...
Show moreArgonne Tandem Linac Accelerator System (ATLAS) is a Department of Energy (DOE) national user research facility, located at Argonne National Laboratory (ANL). Presently, Radioactive Ion Beams (RIBs) produced in the CAlifornium Rare Isotope Breeder Upgrade (CARIBU) facility are charge bred in an Electron Cyclotron Resonance (ECR) charge breeder prior to post acceleration in ATLAS. A new state of the art Electron Beam Ion Source charge breeder, the CARIBU-EBIS charge breeder, has been developed (not in the scope of the work presented here) at ANL to replace the existing ECR for charge breeding RIBs generated in CARIBU. The CARIBU-EBIS charge breeder is now in the final stages of offline commissioning at the Accelerator Development Test Facility (ADTF). A significant part of the commissioning effort has been devoted to testing the source by breeding singlycharged cesium ions injected from a surface ionization source. Characterization of the CARIBU-EBIS performance has been accomplished through a comparison between the measured properties of extracted beams and simulation results. Following its offline commissioning, CARIBU-EBIS will be relocated to its permanent location in ATLAS. An electrostatic transport line has been designed to transport RIBs from CARIBU and inject them into CARIBU-EBIS. In addition, modifications to the existing ATLAS Low Energy Beam Transport (LEBT) were also required in order to transport the charge bred RIBs from CARIBU-EBIS to ATLAS. A proposal for upgrading ATLAS to a multi-user facility has been explored as well. In this context, beam dynamics simulations show that further modifications to the ATLAS LEBT will enable the simultaneous injection and acceleration of RIBs and stablebeams in ATLAS. Furthermore, a novel technique proposed by Ostroumov et al. will allow for the acceleration of multiple charge states from CARIBU-EBIS, thereby increasing the intensity of available RIBs by up to 60%.
Ph.D. in Physics, December 2015
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Title: TRACING TEXTUAL MEDIATING ARTIFACTS AS AGENTS OF CHANGE AND VANGUARDS OF CORPORATE NORMS
Creator: Pappas, George
Date: 2017, 2017-05
Description: Technical communicators often employ user-centered design approaches to design textual artifacts that mediate workplace activity. The artifact...
Show moreTechnical communicators often employ user-centered design approaches to design textual artifacts that mediate workplace activity. The artifact’s designer is positioned as an expert who knows what is best for the artifact’s user (worker). I argue that those methods discount the role of the worker. I apply activity theory as the conceptual framework and genre tracing as the research method to analyze a corpus of documents that mediated the training evaluation activity at ABC Pharmaceutical (a pseudonym for the company’s name) to explain the evolution of those artifacts and theorize the reasons for their historical development. My findings show that their evolution – whether in the form of new genre selections, modifications, splicing, or even abandonment of genres – was influenced by worker efforts that challenged the official expert solutions. The implications of these findings to the fields of technical communication and business research are that even though design experts and business leaders may want to control the organizational strategies, work processes, and mediating artifacts/tools that accomplish those actions, workers will challenge official positions. There are dialectical forces at work that reflect official centripetal efforts that seek organizational stability from formal, normal, and regular structures versus centrifugal efforts that are disruptive and ad hoc in nature. The genre battles Idiscuss in this dissertation reflect a process that should be accepted as healthy and normal by both leadership and design experts, rather than feared or overly regulated.
Ph.D. in Technical Communication, May 2017
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Title: IMPACT OF RELATIONSHIP FUNCTIONING AND PATIENT MOTIVATION ON ADHERENCE AND WEIGHT LOSS AFTER BARIATRIC SURGERY
Creator: Noth, Kathryn
Date: 2013, 2013-07
Description: Background: Bariatric surgery is the most successful intervention to treat severely obese individuals, yet there is significant variability in...
Show moreBackground: Bariatric surgery is the most successful intervention to treat severely obese individuals, yet there is significant variability in surgical outcome (Hsu et al., 1998, Sarwer, Wadden, & Fabricatore, 2005). Success primarily depends on patients’ ability to make and maintain recommended changes to their lifestyle after surgery. Patients’ ability to make and maintain changes to behavior is impacted by elements of the socioenvironmental context. Prior research on a number of different medical populations suggests that an individual’s partner or spouse may facilitate or hinder behavior change (Sher et al, 2011). Study Aim: The current study examined the role of relationship functioning on patients’ motivation for and adherence to health behavior changes and weight loss (%EWL) after bariatric surgery. Based on self-determination theory, it was hypothesized that better relationship functioning, higher levels of autonomous motivation to make lifestyle changes, and less emotional eating (EE) would be associated with better adherence and %EWL after bariatric surgery. Procedure: Participants were 111 women who had undergone a bariatric procedure at least 2 years prior to study participation and who were also in a monogamous relationship for at least six months. Participants completed a series of online questionnaires that assessed relationship functioning, motivation, EE, adherence to recommended changes after surgery, and %EWL. Results: Results indicated that better relationship functioning and higher levels of autonomous motivation were directly associated with better adherence to recommended changes postsurgery. Better adherence to recommended eating behaviors was related to higher %EWL, and both relationship functioning and autonomous motivation were indirectly x associated with %EWL through their impact on eating behavior adherence. Emotional eating was negatively associated with both %EWL and eating behavior adherence. Conclusions: These findings indicate that both individual (motivation, EE) and couples factors (relationship functioning) directly impact patient outcome after bariatric surgery. Clinical application, limitations, and future directions are discussed.
PH.D in Psychology, July 2013
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Title: NOVEL MATERIAL SYNTHESIS THROUGH SOL-GEL AND HYDROTHERMAL METHODS FOR FUNCTIONAL APPLICATIONS
Creator: Wang, Chuanlong
Date: 2014, 2014-05
Description: Novel material synthesis was investigated in this thesis to show two major promising ceramic material Fe-Si-O composites and Na3MnCO3PO4...
Show moreNovel material synthesis was investigated in this thesis to show two major promising ceramic material Fe-Si-O composites and Na3MnCO3PO4 composite. Major processing factors in forming Fe2SiO4=SiO2 and Fe2O3=SiO2 powders via sol-gel synthesis followed by solid-state reactions are investigated. The results clearly indicate that the chemical compositions of the precursors, the ratio of the precursors, the nature of the catalyst used, and the gas atmosphere during solid-state reactions can all a ect the outcome of the reaction product(s). The formation of Fe2SiO4=SiO2 is enhanced by using the precursor iron(III) acetylacetonate as the Fe source with the precursor ratio of iron(III) acetylacetonate to tetraethylorthosilicatebeing 1:1 and the addition of formic acid. Otherwise, crystalline Fe and Fe3C are formed in place of Fe2SiO4. By altering the gas atmosphere during solid-state reactions from argon to oxygen, the reaction products change from Fe2SiO4=SiO2 to Fe2O3=SiO2. All of the observed phenomena can be rationalized via the degree of mixing of the Fe-O and Si-O domains at the molecular level in the gel network during sol-gel reactions and the presence of a reducing or oxidizing atmosphere during the solid-state reaction. Hydrothermal method was applied in synthesizing Na3MnCO3PO4 composite which was studied as a high energy density material for Na ion battery (NIBs). In order to improve electronic conductivity for NIBs battery, ball milling with graphite was introduced for the as-synthesized material. This thesis will investigate the roles played by the ionic conductivities and crystal structure changes introduced by high energy ball milling. Such a study has never been conducted before, and thus can o er guidelines to unlock a gateway to truly low cost Na3MnCO3PO4 cathode NIBs with superior performance.
M.S. in Materials Engineering, May 2014
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Title: INVERSE MINIEMULSION POLYMERIZATION OF PHOSPHATE-LOADED HYDROGEL NANOPARTICLES FOR SEPSIS PREVENTION
Creator: Vadlamudi, Srivishnu
Date: 2014, 2014-05
Description: Drug delivery is an exciting field of interdisciplinary research that has captured the interests of the Pharmaceutical and Biotechnology...
Show moreDrug delivery is an exciting field of interdisciplinary research that has captured the interests of the Pharmaceutical and Biotechnology industry. With the continual advances in discovery and synthesis of effective drugs, it is imperative to create safe and efficient drug-delivery systems. Biocompatible polymer nanoparticles are beginning to provide innovative solutions and form the frontier of advanced drug-delivery technology and Nanomedicine. Phosphate ions have been identified to be instrumental in healing wounds and preventing post-surgery gut-derived sepsis. We have developed a process of inverse miniemulsion polymerization to produce highly crosslinked, Biocompatible PEG diacrylate nanoparticles in the size range of 156-217 nm encapsulated with comprising phosphate ions. An aqueous solution containing high amounts of crosslinker (PEG diacrylate 575), NVP, phosphate salt and a water-soluble thermal initiator was emulsified in cyclohexane (oil-phase) by the application of high shear (ultrasound) to generate an inverse miniemulsion. The aqueous nano-droplets were stabilized against coalescence by the use for two non-ionic surfactants. The presence of phosphate salt within these stable nano-droplets prevented destabilization of the miniemulsion against Ostwald ripening. The encapsulation of phosphate within the nanoparticles is made certain by selecting a phosphate concentration dictated by the PEGDA-Phosphate temperature-dependent thermodynamics. Reported experimental measurements include monomer conversion, particle size measurement and aqueous swelling characteristics. Nanoparticle tracking Analysis (NTA) methodology developed by Nanosight Inc. was used for particle size measurements. A factorial design of experimentation coupled with the application of a xiii kinetic model indicate a low range (10-3 – 10-4) of the initiator efficiency in the reaction kinetics. The comparison of experimental conversion data with model predictions, points towards a well documented notion of a drastic reduction in initiator efficiency that once a critical degree of crosslinking is achieved within the nanoparticles during the reaction. The inverse swelling ratios (proportional to crosslink density) of the nanoparticles tend to substantiate the above kinetic behavior. The preliminary medical testing of the synthesized nanoparticles showed promising results indicating the efficacy of this strategy in drug delivery and regenerative tissue engineering.
M.S. in Chemical Engineering, May 2014
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Title: SYSTEM-ON-CHIP FOR RESEARCH IN ULTRASOUNIC SIGNAL PROCESSING AND IMAGING APPLICATIONS
Creator: Gilliland, Spenser
Date: 2012-05-04, 2012-05
Description: The Ultrasonic Signal Processing System-On-Chip (USPS) provides real-time signal analysis and image processing for the full range of...
Show moreThe Ultrasonic Signal Processing System-On-Chip (USPS) provides real-time signal analysis and image processing for the full range of ultrasound from 20 KHz to 20 MHz. The project aims to make it simple to effectively develop and implement algorithms in embedded software and reconfigurable hardware. This provides the user with an opportunity to explore the full design space including software only, hardware only, and hardware/software co-design. The USPS system provides high speed access to a 12-bit 250 MSPS Maxim MAX1215N ADC controlled by a Xilinx XC5VLX110T FPGA. Access to the ultrasound data and custom coprocessor cores is available through a gigabit Ethernet connection managed by an embedded Linux based operating system running on a Microblaze processor instantiated in the FPGA fabric.
M.S. in Computer Engineering, May 2012
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Title: CHARACTERIZATION OF CELL SURFACE PROPERTIES, CHLORINE RESISTANCE AND SURVIVAL OF ESCHERICHIA COLI O157:H7 STRAINS
Creator: Depa, Keshava Reddy
Date: 2011-11-28, 2011-12
Description: Escherichia coli O157:H7 outbreaks linked to tainted fresh produce have increased during recent years. The aim of this study is to...
Show moreEscherichia coli O157:H7 outbreaks linked to tainted fresh produce have increased during recent years. The aim of this study is to characterize the cell surface properties, chlorine resistance and attachment to leafy greens of several E. coli O157:H7 strains belonging to different phylogenetic clades, in order to reveal if there is any correlation between their survival and bacterial cell surface properties. Six strains chosen among the nine E. coli O157:H7 clades included the fresh produce outbreak associated strains Sakai (1996 sprout outbreak in Japan) and TW14359 (2006 spinach outbreak in the US). The growth kinetics of these strains was compared in BHI broth containing 0.81 ppm free chlorine. Cell surface hydrophobicity, auto-aggregation and curli production were determined by in vitro assays and compared to the generic E. coli strain BW25113. The results showed that these E. coli O157:H7 strains exhibited different chlorine resistances regardless of their phylogenetic distance. They were approximately 20% more hydrophilic (p=0.0072) and showed 77% less auto-aggregated cells (p=0.049) after overnight incubation in broth than the generic E. coli strain. However, no distinguishable hydrophobic or aggregation properties were observed among the six E. coli O157:H7 strains despite their different resistances toward chlorine treatment. Curli production measured by a Congo-Red binding assay in suspension varied among the strains and exhibited no correlation with chlorine resistance. In preliminary studies of chlorine exposure (0.81 ppm) of cells being attached to spinach leaf surface, the spinach outbreak strain TW14359 showed less inactivation (2.6-fold) than the sprout outbreak strain Sakai (15-fold). The information generated from this study will help to develop more effective interventions used in the produce industry.
M.S. in Food Safety and Technology, December 2011
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Title: SECURITY POLICY MANAGEMENT, THREAT ALLEVIATION AND TRUSTED PLATFORMS FOR EMBEDDED COMPUTING SYSTEMS
Creator: Anand, Vijay
Date: 2011-08, 2011-07
Description: Security guarantees are a measure of trust that can be placed on computing services in the safeguarding of digital assets. These security...
Show moreSecurity guarantees are a measure of trust that can be placed on computing services in the safeguarding of digital assets. These security goals and guarantees coupled with known and modeled threats to the digital assets shape the security policies for computing services. The creation, management and implementation of security policies in computing services is a challenge in defining the role of policy, the management principle for decision making when posed with threats and overall control over digital assets in a well-defined manner. In this Ph.D. thesis we establish a causal relationship of security policies with threats, provide an industry standard management framework (Six Sigma) for decision making, changes to the constructs of the trusted platform module to create a control framework and, finally show how the security framework can be used in a commercial service. The process of updating and refactoring security policy changes becomes a time consuming and tedious task, especially when threats evolve and computing service constructs change when security policy implementations are implicitly implemented. With the basis of correlation of policies over threats an explicit security policy implementation is proposed such that its adaptability, testability and risk quantification can be achieved when threats evolve. In this study we explore policy threat correlation on a Trusted Platform Module (TPM), a hardware system entrusted with security operations and guarantees. An effective TPM needs to adapt to evolving threats arising from firmware bugs or decay in the complexity of ciphering algorithms. Therefore, an adaptive TPM architecture is proposed to counter evolving threats by integrating an FPGA (Field Programmable Gate xi Arrays) block to alter and patch firmware and change ciphering systems. We present how security guarantees in an IT(Information Technology) infrastructure can be met using a TPM and thereby should be an integral part of computing services along with other security constructs like firewalls, intrusion detection systems, anti-virus, etc.. Adaptive security policy requires a management process wherein the risk management, and cost effectiveness principles can be identified. This is essential to make decisions on the trust criteria of digital assets in an industrial management framework. The security policy creation and management process presented in this thesis is based on Six Sigma model and presents a method to adapt security goals and risk management in an industrial framework. As an effective implementation of the security policy the case of application commerce workflow for developers is presented. Secure application distribution and execution guarantees lie in the transfer of trust between various processes in a computing service, also known as Chain of Trust in an embedded system. This study presents application development workflows facilitating secure commerce of digital assets thereby improving consumer trust.
Ph.D. in Computer Engineering, July 2011
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Title: SHORT AND ULTRASHORT-PULSED LASER-MATERIAL INTERACTIONS: MODELING AND COMPARISONS WITH EXPERIMENTS
Creator: Tao, Sha
Date: 2013, 2013-07
Description: Lasers have wide applications in numerous areas. Laser-based applications and technologies often involve certain types of laser-material...
Show moreLasers have wide applications in numerous areas. Laser-based applications and technologies often involve certain types of laser-material interactions, many of which have not been sufficiently understood. In this thesis, through the development of the corresponding physics-based models and the comparisons of modeling results with relevant experiments (when available), the laser-material interaction mechanisms during the following processes will be studied: i) laser ablation of semiconductors; ii) laser-material interactions inside microholes; and iii) laser-induced plasma evolution (more detailed conditions of the studied processes are given in the thesis). This research work is expected to improve the understanding of laser-material interaction mechanisms in the above investigated processes, which may provide information that is useful for the improvement of many related existing laser-based applications or technologies and for the development of novel ones.
PH.D in Mechanical and Aerospace Engineering, July 2013
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Title: MODELING, ANALYSIS AND CONTROL OF COMPLEX ADAPTIVE SYSTEMS
Creator: Ozturk, Mustafa Cagdas
Date: 2015, 2015-07
Description: A comprehensive approach to the incorporation of adaptive behavior into complex systems is provided through attentive combination of a wide...
Show moreA comprehensive approach to the incorporation of adaptive behavior into complex systems is provided through attentive combination of a wide variety of methods from di↵erent fields. Two examples of complex systems were subjected to this approach, which involves modeling, analysis and control of the processes. The first system of interest is an autocatalytic reactor with multiple resources and multiple species. A continuous stirred-tank reactor model was developed, and subsequently analyzed using bifurcation analyses. The multiplicity character of the system was investigated, and emergent features, such as stable coexistence of autocatalysts, were discovered. Next, an agent-based control system was implemented on the process model using finite-state machines with simple rules as local control elements. The control system is capable of transitioning the process between the numerous steady states evidenced by the bifurcation analysis, as well as exploring the state space for a feasible steady state, given arbitrary set points for the autocatalysts. Eventually, Equation-Free coarse graining methods were applied to this model to investigate the local stability of the agent-controlled system. It was shown that this approach indeed was able predict the correct stability behavior for a given steady state, using only input-output information from short simulations with the closed-loop system. The second system considered was the activated sludge process, which was modeled based on data from an existing wastewater treatment plant. This realistic and complex model was then subjected to in-depth bifurcation analyses using various model parameters. The bifurcation analyses revealed many interesting phenomena about the process, including steady state multiplicity and conditional stability. In addition, potential risks of operation under certain conditions, such as the loss of biomass, were outlined. Furthermore, the aeration requirement of the process was investigated and the possibility for 55% savings in aeration with the same e✏uent quality was illustrated. Finally, in order to enhance the potential of savings in aeration, an agentbased control system was implemented on the activated sludge process. This control system optimized the local airflow rates in real time, and provided a decrease of up to 65% in the aeration rate. In addition, the process was shown to endure severe storm events and aeration failures thanks to the adaptive features of the agent-based control system.
Ph.D. in Chemical Engineering, July 2015
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Title: ANISOTROPIC MICROSRHEOLOGY OF SELF-ASSEMBLING COLLAGEN NETWORKS
Creator: Dutov, Pavel
Date: 2015, 2015-05
Description: Collagen is the main component of human connective tissue and extracellular matrix. Here we report multiple novel methods for utilizing...
Show moreCollagen is the main component of human connective tissue and extracellular matrix. Here we report multiple novel methods for utilizing optical tweezers to measure mechanical properties of different hierarchical levels of collagenous materials. First, we introduce a method for optical trap calibration that is suitable for viscoelastic material. The method is designed for use on experimental setups with two optical tweezers and is based on pulling a trapped particle with one trap while holding it with the other. The method combines advantages of commonly known PSD-fitting and fast-sweeping methods, allowing calibration of a completely fixed trap in a fluid of unknown viscosity/viscoelasticity without additional expensive equipment. Then we report an approach to measure the longitudinal component of the elastic moduli of biological fibers under conditions close to those found in vivo and apply it to type I collagen from rat tail tendon. This approach combines optical tweezers, atomic force microscopy, and exploits Euler-Bernoulli elasticity theory for data analysis. The approach also avoids the traditional drying-soaking cycle, since samples are freshly extracted. Importantly, strains are kept below 0.5%, which appear consistent with the linear elastic regime. We find, surprisingly, that the longitudinal elastic modulus of type I collagen cannot be represented by a single quantity but rather is a distribution that is broader than the uncertainty of our experimental technique. Lastly, we report a new method for characterizing anisotropic viscoelastic response of collagenous matrices. Anisotropic collagenous extracellular matrices are used in biomedicine to enhance the wound healing process by directing fibroblast proliferation. We utilize an optical trap to monitor the thermal fluctuations of microspheres embedded into collagenous network to extract a viscoelastic response function of the network along the principal axes of anisotropy.
Ph.D. in Chemical Engineering, May 2015
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Title: Development of Granular Jamming Soft Robots from Boundary Constrained to Interconnected Systems
Creator: Tanaka, Koki
Date: 2023
Description: This dissertation provides a detailed study on the conceptualization, creation, and optimization of a unique, interconnected soft robot system...
Show moreThis dissertation provides a detailed study on the conceptualization, creation, and optimization of a unique, interconnected soft robot system. It introduces a flexible assembly of locomotive robotic modules interconnected by an envelope, capable of granular jamming. In doing so, it highlights the practical capabilities of these interconnected modules to adapt and function cohesively as a single robot system.As a precursor to the primary investigation, the study initially presents the development and experimental validation of a boundary constrained mobile soft robot. This design leverages granular jamming for locomotion and object grasping, thereby laying a robust foundation for the subsequent exploration of complex soft robotic systems.The cornerstone of this study is the development of an interconnected soft robot system, where locomotive robotic modules, primarily composed of an elastic material, are bound together by a flexible envelope designed for granular jamming. The robotic modules, fundamentally constructed from an elastic material, incorporate origami-inspired artificial muscle actuators. These actuators, with their semi-soft characteristics, complement the inherent flexibility of the modules and play a significant role in facilitating module propulsion. Although the design incorporates a traditional rigid power source, as opposed to a fully soft robot system, the integration of a pneumatic power method into the system successfully reduces the mechanical intricacy and unwieldiness typically associated with rigid mechanisms.This research further probes into the diverse applications of this interconnected soft robot system. Its ability to shape-shift and maintain these forms during locomotion exemplifies a robust control strategy for the system that may undergo substantial deformation, proving instrumental in dynamic environments. The study demonstrates a methodology for object manipulation and obstacle avoidance that does not rely heavily on precise control and sensing. Instead, it utilizes the inherent compliance of the soft robot system. In a notable departure from previous studies, the system also exhibits a unique capability for ascending and traversing inclined surfaces.Additionally, the study dives into the optimization of the interconnected robot system via a physics-based simulation and genetic algorithm. This approach results in an assortment of optimized configurations that excel in object grasping tasks of various shapes, thereby laying a robust groundwork for the progression of soft robotics in the future.In conclusion, this investigation reveals groundbreaking insights into the field of soft robotics through the successful design and optimization of an interconnected soft robot system. Its standout performances in deformation, manipulation, and navigation tasks set it apart. This work serves to significantly enhance the adaptability and functionality of future robotic systems, pushing the edge of what is possible across a diverse range of sectors. By portraying a significant step towards a future where robots can dynamically adapt to their environments and efficiently accomplish complex tasks, this dissertation exemplifies a transformative stride in the field.
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Title: Efficacy and Mechanisms of Power Ultrasound-Based Hurdle Technology for Reduction of Pathogens in Fresh Produce
Creator: Zhou, Xinyi
Date: 2023
Description: Minimally processed produce is frequently contaminated with foodborne bacterial pathogens. Power ultrasound is a non-thermal and cost...
Show moreMinimally processed produce is frequently contaminated with foodborne bacterial pathogens. Power ultrasound is a non-thermal and cost-effective technology that can be combined with other chemical sanitization methods. This study investigated the reduction of Listeria monocytogenes and Salmonella Newport on grape tomato, romaine lettuce, and spinach washed with water, chlorine, or peroxyacetic acid alone or in combination with 25 or 40 kHz power ultrasound for 1, 2, or 5 min. Produce items were inoculated with selected pathogens at approximately 10 log CFU/g, air dried for 2 h, and then treated. Combined treatment of ultrasound and sanitizers resulted in 1.44-3.99 log CFU/g reduction of L. monocytogenes and 1.35-3.62 log CFU/g reduction of S. Newport on washed produce items, with significantly higher reductions observed on grape tomato. Synergistic effects were achieved with the combined treatment of power ultrasound coupled with the chemical sanitizers when compared to the single treatments. An additional 0.48-1.40 log CFU/g reduction of S. Newport was obtained with the combined treatment on grape tomato. In general, no significant differences (p<0.05) were observed in pathogen reductions between the selected ultrasound frequencies, sanitizers, or treatment lengths. Results from this study suggest that incorporation of power ultrasound to current treatment can enhance bacterial pathogen reduction on fresh produce surface, but cannot completely eliminate bacterial pathogens. Transcriptomic study revealed significant (|Log2 fold change|<1 and false discovery rate < 0.05) transcriptional changes in L. monocytogenes LS810 in response to the 2 min power ultrasound treatment. The up-regulation of genes encoding TPI, LLO, and PTS indicates increased energy requirements, enhanced virulence, and demand for sugar sources in bacteria. On the other hand, the down-regulation of genes involved in cyclic dimeric GMP hydrolysis and transcriptional regulation suggests a modulation of intracellular signaling, cellular processes, and metabolisms to enhance survival and recovery. The GO and KEGG analysis demonstrated defense mechanisms against ultrasound stress more comprehensively. L. monocytogenes adjusts its metabolism, repairs cell membranes, and conserves energy for survival. These findings enhance our understanding of its adaptation to environmental stress. Results of this study can be used as a start point for optimizing the efficacy of ultrasound-based hurdle treatments for fresh produce disinfection.
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