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Title: ELECTROCHEMICAL, TRANSPORT AND THERMAL INVESTIGATION OF NOVEL ELECTROLYTES AND ELECTRODES FOR LITHIUM-ION AND MAGNESIUM-ION BATTERIES
Creator: Benmayza, Aadil
Date: 2014, 2014-12
Description: Energy conversion and energy storage are becoming indispensable in today’s society due to the increased demand for immobile and mobile power....
Show moreEnergy conversion and energy storage are becoming indispensable in today’s society due to the increased demand for immobile and mobile power. Cathode material is considered as the only source of energy in the electrochemical cell for secondary battery and thus the quantity of energy of the battery is largely determined by the type of the cathode’s chemistry and its amount used as well. Electrolyte has also a significant impact on the electrochemical performance of the battery. Its properties such as ionic conductivity and transference number play a substantial role in the transport of energy between the cathode and the anode. Moreover, the electrolyte can also limit the accessibility of the active charged ions into the active material through the formation of a Solid Electrolyte Interface (SEI). In addition to the importance of energy, safety is another critical element in the determination of the battery’s quality. Cathode material and non-aqueous electrolyte are two major dimensions of the safety in the design of secondary battery. For instance, in the presence of heat (due to thermal, mechanical, or electrical abuse), the electrolyte can ignite fire if the cathode material releases the oxygen. Therefore, the cathode materials and electrolytes are both central factors in the determination of battery energy and safety. Nowadays, lithium-ion batteries are widely used as power source in many applications; however, their maximum energy density (400Wh/Kg) is not sufficient enough to meet the demands of high power applications such as electric vehicles owing to the limited driving range caused by current lithium-ion batteries. Furthermore, safety concerns have been raised after several incidents have been reported recently. Therefore, improving the safety of lithium-ion battery systems through the formulation of non-flammable electrolytes and synthesizing stable electrodes are highly required for high thermal stability. In contrast, fulfilling the long driving range requires other battery systems that provide higher energy density. The large energy density of Mg metal (3832 mAh/cm3) opens a new horizon toward future potential energy storage system, which is a very promising candidate to overcome the long driving range issue and thus needs to be investigated for its potential use as rechargeable battery. In this present thesis, thermal stability of lithium-ion cells is examined through the use of Fluoro Ethylene Carbonate (FEC) as non-flammable co-solvent with Ethylene Carbonate (EC) on lithium-nickel-cobalt-aluminum-oxide cathode (LiNi0.8Co0.15Al0.05O2). This cathode chemistry was deliberately chosen because of its low thermal stability due to the oxidation of Ni+3 to Ni+4 upon charging. Additionally, optimization of the cathode composition (active material, conducting agent, binder) was examined for high energy and power. Lithium iron phosphate (LiFePO4) was chosen for this study because of its high thermal stability against the liberation of oxygen. Electrolytic properties of a magnesium organohaloaluminate electrolyte were investigated in order to understand their role and effect on the magnesium deposition process. Electrochemical and thermal study of bismuth material as a potential negative electrode for magnesium-ion cell under the use of magnesium organohaloaluminate electrolyte was also performed. Moreover, a thermal modeling was performed through the use of Isothermal-Micro-Calorimeter (IMC) technique to identify the sources of heat released during the magnesiation and demagnesiation of bismuth electrode.
Ph.D. in Chemical Engineering, December 2014
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Title: SUPERVISED AND INTERACTIVE IMAGE SEGMENTATION TECHNIQUES WITH AN APPLICATION TO PROSTATE CANCER
Creator: Artan, Yusuf Oguzhan
Date: 2013, 2013-05
Description: Prostate cancer is a leading cause of cancer death for men in the United States. Fortunately, the survival rate for early diagnosed patients...
Show moreProstate cancer is a leading cause of cancer death for men in the United States. Fortunately, the survival rate for early diagnosed patients is relatively high. Accurate prostate cancer localization with noninvasive imaging using MRI can be used to guide biopsy, radiotherapy, and surgery as well as to monitor disease progression. However, in general, a single type of MRI is not sufficient for reliable tumor localization. As an alternative, multispectral MRI, i.e., the use of multiple MRI-derived datasets, has emerged as a promising noninvasive imaging technique for the localization of prostate cancer; however almost all studies are with human readers. There is a significant inter and intra-observer variability for human readers, and it is substantially difficult for humans to analyze the large dataset of multispectral MRI. To solve these problems, this thesis presents various novel supervised and semi- supervised (interactive) segmentation techniques. Initially, we develop a supervised segmentation method by combining conditional random fields (CRF) and support vector machines (SVM) with a cost-sensitive framework, and show that proposed method further improves classical and cost-sensitive SVM results by incorporating spatial information. Next, we propose an extension of popular semi-supervised seg- mentation method, namely random walker (RW) algorithm, with automated seed initialization for multispectral MRI images. We also present an automated shape and boundary based segmentation approach for prostate segmentation from T2-weighted MRI. Proposed method is based on a banded geocuts algorithm that utilizes bound- ary and shape information to yield prostate segmentation. Finally, we develop a novel method that has the ability to design classifiers obtained from one imaging protocol and/or MRI device to be used on a dataset from another protocol and/or imaging device. In order to evaluate the performance of the proposed methods, we utilize multispectral MRI datasets acquired from 21 biopsy-confirmed cancer patients. Our results show that multispectral MRI helps to increase the accuracy of prostate cancer xiv localization when compared to single MR images; and that using advanced proposed methods for prostate cancer localization performs better than available methods in the literature.
PH.D in Electrical Engineering, May 2013
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Title: AUTOMATED MANIPULATION OF NANOSCALE STRUCTURES VIA AN ATOMIC FORCE MICROSCOPE
Creator: Xu, Kangmin
Date: 2013, 2013-05
Description: As a useful tool for both imaging and modifying nanoscale structures, atomic force microscopes (AFM) have drawn many researchers’ attention,...
Show moreAs a useful tool for both imaging and modifying nanoscale structures, atomic force microscopes (AFM) have drawn many researchers’ attention, but there are still many challenges such as lack of visual feedback during manipulation. In this dissertation, an AFM based nano manipulation system has been developed to modify the nanoscale structures including manipulation of nano particles, carbon nanotubes (CNTs) and indentation of the polymer substrate. These operations have been further assisted by real-time feedback such that AFM can be used to image, sense and manipulate nanoscale objects simultaneously. To address critical issues in AFM based nano manipulation, several methods have been developed to enhance the process of manipulation. In nano particle manipulation, a method called sequential parallel pushing (SPP) is presented for efficient and automated nano particle manipulation. Instead of using tip scanning to fully locate the particle center, this method uses contact loss detection to get the longitudinal position of particle and one scan line perpendicular to the pushing direction to determine the lateral position of the particle center. In nano indentation, computer-aided design (CAD) geometry processing has been integrated with an AFM based nano indentation process which enables the fabrication of complex geometric features. Machining parameters have been investigated and procedure to determine them have been demonstrated. In the localization of deformable nanoscale objects, two localization methods for localizing CNTs and nanowires have been introduced. They can perform accurate positioning and reconstruction of sample shapes while being manipulated. Successive manipulation strategies thus can be developed based on the developed fast localization schemes.
PH.D in Mechanical Engineering, May 2013
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Title: LEADING IN UNCERTAIN TIMES: WHAT DRIVES FOLLOWERS' PERFORMANCE?
Creator: Arena, Fernando Lobo
Date: 2016, 2016-05
Description: Using a sample of 109 managers and 307 direct reports from a global financial services firm headquartered in the United States, we examined...
Show moreUsing a sample of 109 managers and 307 direct reports from a global financial services firm headquartered in the United States, we examined how trustworthiness affected the relationship between authentic leadership and performance in followers. Additionally, we examined how trustworthiness drives performance in an environment of strategic and structural uncertainty. Our findings indicate that authentic leadership drives follower performance and that this relationship may be mediated by benevolence. However, in a post hoc analysis we did show that benevolence mediated the relationship between relational transparency and performance. While not conclusive, there is also evidence to suggest that structural uncertainty moderates the relationship between benevolence and performance. In an environment of high structural uncertainty, followers that perceive their leaders as benevolent tend to outperform other followers.
Ph.D. in Psychology, May 2016
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Title: AUDITORY PROCESSING AND THE EXTRACTION OF SOCIAL EMOTIONAL CUES IN AUTISM
Creator: Demopoulos, Carly
Date: 2013, 2013-07
Description: There is increasing evidence that there are deficits in vocal affect recognition abilities in some individuals diagnosed with Autism Spectrum...
Show moreThere is increasing evidence that there are deficits in vocal affect recognition abilities in some individuals diagnosed with Autism Spectrum Disorders (ASDs) and that sensory deficits are also common in these individuals. Little research, however, has focused on the relation between atypical auditory processing and vocal affect recognition abilities. The aim of this study was to examine if there was an association between cortical auditory processing and vocal affect recognition ability, and, in turn, to determine if vocal affect recognition ability was related to parent report of social and leadership skills. First, peripheral auditory processing was examined in a sample of 28 5-18 yearold (mean = 11.48) children and adolescents with an ASD. Vocal affect recognition was assessed by the paralanguage subtests of the Diagnostic Analysis of Nonverbal Accuracy (DANVA), and magnetoencephalography (MEG) was used to evaluate cortical electrophysiological processing in relation to auditory stimuli. Parent-report was used to assess social skills and leadership with these subtests on the Behavior Assessment Scale for Children-2. Correlational analyses indicated that there were no significant relations between peripheral auditory processing and DANVA scores. Results of hierarchical regression analyses indicated that, after controlling for age, language ability, and IQ, the measures of cortical auditory processing contributed a significant additional 19% of the variance in DANVA-2 scores. Specifically, left hemisphere response latency and right hemisphere rapid auditory processing were related to vocal affect recognition. They also indicated that DANVA-2 scores contributed a significant additional 30% of the variance in parent-rated social skills after controlling for language ability and IQ. However, DANVA-2 scores did not contribute significantly to leadership skills. xi This was the first study to use magnetoencephalography (MEG) to assess auditory evoked fields in relation to vocal affect recognition and to show that there is an association between specific features of cortical auditory processing and vocal affect recognition. These results suggest that the ability to respond to and efficiently process rapidly presented auditory information may be important in extracting affective cues from speech, and for individuals on the autism spectrum, impairment in these abilities may contribute to difficulty in vocal affect recognition.
PH.D in Psychology, July 2013
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Title: PHYSICS OF LIMITING PHENOMENA IN SUPERCONDUCTING MICROWAVE RESONATORS: VORTEX DISSIPATION, ULTIMATE QUENCH AND QUALITY FACTOR DEGRADATION MECHANISMS
Creator: Checchin, Mattia
Date: 2016, 2016-12
Description: Superconducting niobium accelerating cavities are devices operating in radiofrequency and able to accelerate charged particles up to energy of...
Show moreSuperconducting niobium accelerating cavities are devices operating in radiofrequency and able to accelerate charged particles up to energy of tera-electron-volts. Such accelerating structures are though limited in terms of quality factor and accelerating gradient, that translates—in some cases—in higher capital costs of construction and operation of superconducting rf accelerators. Looking forward for a new generation of more affordable accelerators, the physical description of limiting mechanisms in superconducting microwave resonators is discussed. In particular, the physics behind the dissipation introduced by vortices in the superconductor, the ultimate quench limitations and the quality factor degradation mechanism after a quench are described in detail. One of the limiting factor of the quality factor is the dissipation introduced by trapped magnetic flux vortices. The radio-frequency complex response of trapped vortices in superconductors is derived by solving the motion equation for a magnetic flux line, assuming a bi-dimensional and mean free path-dependent Lorentzian-shaped pinning potential. The resulting surface resistance shows the bell-shaped trend as a function of the mean free path, in agreement with the experimental data observed. Such bell-shaped trend of the surface resistance is described in terms of the interplay of the two limiting regimes identified as pinning and flux flow regimes, for low and large mean free path values respectively. The model predicts that the dissipation regime—pinning- or flux-flow-dominated—can be tuned either by acting on the frequency or on the electron mean free path value. The effect of different configurations of pinning sites and strength on the vortex surface resistance are also discussed. Accelerating cavities are also limited by the quench of the superconductive state, which limits the maximum accelerating gradient achievable. The accelerating field limiting factor is usually associated to the superheating field, which is intimately correlated to the penetration of magnetic flux vortices in the material. Experimental data for N-doped cavities suggest that uniform Ginzburg-Landau parameter cavities are statistically limited by the lower critical field, in terms of accelerating gradient. By introducing a Ginzburg-Landau parameter profile at the cavity rf surface—dirty layer—the accelerating gradient of superconducting resonators can be enhanced. The description of the physics behind the accelerating gradient enhancement as a consequence of the dirty layer is carried out by solving numerically the Ginzburg-Landau equations for the layered system. The enhancement is showed to be promoted by the higher energy barrier to vortex penetration, and by the enhanced lower critical field. Another serious threat to the quality factor during the cavity operation is the extra dissipation introduced by the quench. Such quality factor degradation mechanism due to the quench, is generated by the trapping of external magnetic flux at quench spot. The purely extrinsic origin of such extra dissipation is proven by the impossibility of decrease the quality factor by quenching in a magnetic field-free environment. Also, a clear relation of the dissipation introduced by quenching to the orientation of the applied magnetic field is observed. The full recover of the quality factor by re-quenching in compensated field is possible when the trapped flux at the quench spot is modest. On the contrary, when the trapped magnetic flux is too large, the quality factor degradation may become irreversible by this technique, likely due to the outward flux migration beyond the normal zone opening during the quench.
Ph.D. in Physics, December 2016
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Title: MICROGRIDS AND DISTRIBUTED GENERATION SYSTEMS: CONTROL, OPERATION,COORDINATION AND PLANNING
Creator: Che, Liang
Date: 2015, 2015-07
Description: Distributed Energy Resources (DERs) which include distributed generations (DGs), distributed energy storage systems, and adjustable loads are...
Show moreDistributed Energy Resources (DERs) which include distributed generations (DGs), distributed energy storage systems, and adjustable loads are key components in microgrid operations. A microgrid is a small electric power system integrated with onsite DERs to serve all or some portion of the local loads and connected to the utility grid through the point of common coupling (PCC). Microgrids can operate in both gridconnected mode and island mode. The structure and components of hierarchical control for a microgrid at Illinois Institute of Technology (IIT) are discussed and analyzed. Case studies would address the reliable and economic operation of IIT microgrid. The simulation results of IIT microgrid operation demonstrate that the hierarchical control and the coordination strategy of distributed energy resources (DERs) is an effective way of optimizing the economic operation and the reliability of microgrids. The benefits and challenges of DC microgrids are addressed with a DC model for the IIT microgrid. We presented the hierarchical control strategy including the primary, secondary, and tertiary controls for economic operation and the resilience of a DC microgrid. The simulation results verify that the proposed coordinated strategy is an effective way of ensuring the resilient response of DC microgrids to emergencies and optimizing their economic operation at steady state. The concept and prototype of a community (networked) microgrid that interconnecting multiple microgrids in a community are proposed. Two works are conducted. For the coordination, novel three-level hierarchical coordination strategy to coordinate the optimal power exchanges among neighboring microgrids is proposed. For the planning, a multi-microgrid interconnection planning framework using probabilistic minimal cut-set (MCS) based iterative methodology is proposed for enhancing the economic, resilience, and reliability signals in multi-microgrid operations. The implementation of high-reliability microgrids requires proper protection schemes that effectively function in both grid-connected and island modes. This chapter presents a communication-assisted four-level hierarchical protection strategy for highreliability microgrids, and tests the proposed protection strategy based on a loop structured microgrid. The simulation results demonstrate the proposed strategy to be an effective and efficient option for microgrid protection. Additionally, microgrid topology ought to be optimally planned. To address the microgrid topology planning, a graph-partitioning and integer-programming integrated methodology is proposed. This work is not included in the dissertation. Interested readers can refer to our related publication.
Ph.D. in Electrical and Computer Engineering, July 2015
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Title: THE CONTEXTUAL-SCENARIO FRAMEWORK FOR REPRESENTING SUBJECTIVE EXPERIENCE
Creator: Swanson, Eric
Date: 2013, 2013-05
Description: No abstract
PH.D in Design, May 2013

Title: Efficiency test of a four cylinder four cycle twenty horse power automobile gasoline engine
Creator: Smith, C. U.
Date: 2009, 1907
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/efficiencytestof00smit
Thesis (B.S.)--Armour Institute of Technology; Bibliography: leaf 41

Title: ELECTROCHEMICAL CONTINUOUS AND AB INITIO DFT MODELING OF ELECTRODE REACTIONS IN PEM FUEL CELLS, AND LI-ION AND MAGNESIUM BATTERIES
Creator: Ramanathan, Mayandi
Date: 2013, 2013-07
Description: Electrochemical energy conversion and storage systems are set to play a major role in the scheme of providing clean and renewable energy to...
Show moreElectrochemical energy conversion and storage systems are set to play a major role in the scheme of providing clean and renewable energy to the growing energy demands, both in the nearby and long-term future. PEM fuel cells are the widely tested energy conversion devices with hydrogen as fuel and air as oxidant. Li-ion batteries are commercialized for short and medium range energy demands. But for fulfilling the long range energy demands, research in some new technologies such as Li-air, Magnesium and Sodium batteries are in progress. Magnesium batteries have huge potential to be a high energy density battery suitable for long range electric vehicles and electrical grid energy storage. In PEM fuel cells, Oxygen reduction reaction is the performance limiting factor due to the sluggish reaction kinetics and expensive, but relatively stable Pt catalyst. In the present study, combined DFT modeling and experimental annealing procedure is being employed to improve the ORR activity of Pd by alloying with transition metal elements such as Ni, Cu and Fe. In Li-ion battery, LiFePO4 is the widely commercialized cathode material, but it suffers its limitation of possessing poor electronic conductivity, which affects the cell performance at high discharge rates. A simple isothermal, one-dimensional John Newman Li-ion battery model is being employed to study the effects of changes in LiFePO4, carbon and binder composition towards changes in electrode porosity, electrical conductivity and cell capacity. With the help of modeling results, an optimum composition zone is located for optimizing the high rate performance. In Magnesium batteries, a modified isothermal, one-dimensional John Newman battery model was employed to study the characteristics of the Mg intercalation reactions, predict the performance of the Bi anode electrode and also understand the underlying phenomena and properties that dictate the characteristics of the Mg intercalation in Bi electrode.
PH.D in Chemical Engineering, July 2013
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Title: PHOTOCONDUCTIVE SWITCH IMPLEMENTED WITH GALLIUM ARSENIDE ON SILICON NITRIDE FOR COPLANAR WAVEGUIDE BASED TERAHERTZ SPECTROMETER
Creator: Fu, Xiaohuan
Date: 2015, 2015-12
Description: Over the years, pulsed terahertz (THz) time domain spectroscopy has attracted a lot of interest since it can not only measure the intensity of...
Show moreOver the years, pulsed terahertz (THz) time domain spectroscopy has attracted a lot of interest since it can not only measure the intensity of the transient electric eld but also determine the amplitude and phase of the spectral components that make up the pulse. This provides a convenient method to obtain the molecular network information of chemical or biological samples. Signi cant e orts have been directed towards free space spectroscopy in which THz pulses travel in free space between photoconductive transceivers. Due to di raction limit, the resolution is insu cient for many applications and it results in extreme power requirements or low power densities of the probe pulse. To overcome this issue, we propose a planar THz spectrometer which uses the same photoconductive excitation and detection mechanism as free space spectroscopy, but the excited THz pulses are directly coupled into lithographically de ned coplanar transmission lines. To reduce the power loss in the substrate, a thin lm with lower permittivity is employed to replace the conventional silicon substrate at the location where the coplanar waveguide is fabricated. To obtain high sensitivity, sample can be directly placed on the coplanar waveguide for tight coupling of the eld. Conceptual design and EM simulations have been completed and a variety of experimental studies have been carried out at Argonne National Laboratory to understand the fundamentals of coplanar waveguide. The fabrication of the coplanar waveguide prototype have been conducted at Northern Illinois University. The challenge of building a photoconductive switch with LTG-GaAs on Si3N4 was encountered and an innovative wafer bonding technique was discovered. Several wafer treatments prior to and after wafer bonding have been demonstrated to improve the bonding strength and reduce the defects. A standard pump-probe optics setup has been built at DePaul University and the photoconductive switch have been tested with femtosecond laser. The results con rmed that the photoconductive switches are functioning as design and the device system is ready for THz spectroscopy application. The historical overview of THz spectroscopy research and fundamentals of coplanar waveguide and photoconductive switches are presented in Chapter 1-3, followed by EM simulation, conceptual design in Chapter 4. The details of microfabrication process and the testing results are discussed in Chapter 5 and 6. The project is summarized in Chapter 7.
Ph.D. in Electrical Engineering, December 2015
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Title: REVISITING THE URBAN BLOCK IN THE LIGHT OF CLIMATE CHANGE A CASE STUDY OF BUDAPEST
Creator: Gal, Csilla Viktoria
Date: 2014, 2014-07
Description: Since the beginning of the twentieth century, the urban block configuration of free-standing buildings has been deemed superior to other built...
Show moreSince the beginning of the twentieth century, the urban block configuration of free-standing buildings has been deemed superior to other built forms, as it provided the necessities of modern healthy living: sunlight and fresh air. In light of climate change, the dissertation aims to reevaluate these long held beliefs and to reintroduce microclimate as an urban design consideration. The study takes four metropolitan block typologies of Budapest as cases to clarify the microclimate influence of key urban design parameters by means of a numerical simulation study. The effects of built form, orientation, vegetation and facade properties are evaluated for a typical summer day. The cases are assessed on the basis of diurnal potential air and mean radiant temperatures within the urban canopy layer. Numerical modeling is performed by ENVI-met and analysis is conducted with MATLAB. The findings indicate that built form and vegetation are key factors governing the microclimate. During the day, intraurban cool island develops between dense configurations and in tree-shaded urban canopies. Orientation is decisive in configurations with large open spaces, where east-west alignment corresponds with peak radiant and air temperatures. Apart from albedo, facade properties have little effect on the microclimate. The rise of air temperature with facade albedo is the outcome of canopy floor heating, resulting from the increased ratio of reflected shortwave radiation. A short-term field experiment was conducted in Budapest to complement the numerical simulation study and to evaluate ENVI-met. The measurement campaign utilized six air temperature and humidity loggers. Additionally, wind speed, air temperature and humidity were recorded at the pedestrian level during an anticyclonic period. In courtyards, thermal stratification developed by day with cool island intensities up to 7 C. In the case of open configurations, neither cool island, nor stratification was observed. The comparison of measured and predicted air temperatures revealed the strengths and weaknesses of the numerical model. In general, predicted temperatures had a decreased diurnal range with maximum values systematically underestimated. ENVI-met also failed to reproduce the thermal stratification in courtyards. Despite these shortcomings, the predicted trends and the relative microclimate differences between the configurations agreed with observations reasonably well.
Ph.D. in Architecture, July 2014
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Title: THE ASSOCIATIONS AMONG EMOTIONAL EATING, GENDER, BMI, AND RUMINATION
Creator: Gabelman, Rachel Beth
Date: 2017, 2017-07
Description: The purpose of this study was to gain a better understanding of the roles of gender, body mass index (BMI), and rumination in the relation of...
Show moreThe purpose of this study was to gain a better understanding of the roles of gender, body mass index (BMI), and rumination in the relation of negative affect (NA) and emotional eating (EE). The following associations were proposed: (1) NA is positively associated with EE, (2) rumination both moderates and (3) mediates the association between NA and EE, (4) gender moderates the association between NA and emotional eating, and (5) EE mediates the association between NA and BMI. Participants consisted of average, overweight, and obese, males (n = 140) and females (n = 152) from both community and university settings. Participants completed self-report questionnaires, including the Binge Eating Questionnaire, Positive and Negative Affect Scale, Dutch Eating Behavior Questionnaire, and Ruminative Response Questionnaire. Results agreed with previous findings that NA positively correlated NA was positively associated with EE. Results indicated that rumination moderated the association between NA and EE; however rather than greater rumination strengthening this association, it led to a weaker association between NA and EE. Rumination mediated the association between NA and EE, and EE mediated the association between NA and BMI. Lastly, gender did not moderate the association between NA and EE. Results indicate the importance of rumination in those with a tendency to emotionally eat. They also point to the impact of EE on BMI, and suggest further studies should examine whether an association exists between EE and weight gain. In addition, results indicate similarities between men and women in regard to emotionally eating in response to NA.
Ph.D. in Psychology, July 2017
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Title: NUMERICAL MODELING AND ANALYSIS OF CAVITATION IN WATER AND LASER-INDUCED PLASMA AMPLIFICATION FOR MICROMACHINING APPLICATIONS
Creator: Dabir-moghaddam, Navid
Date: 2017, 2017-05
Description: Machining processes are needed in many industrial areas. Laser-based machining often has the advantages such as high spatial resolution, no...
Show moreMachining processes are needed in many industrial areas. Laser-based machining often has the advantages such as high spatial resolution, no mechanical tool wear, etc., and has current and potential applications in many areas. The objective of this research work is to conduct physics-based modeling studies to help the understanding of some physical processes relevant to two novel laser-based machining processes: (i) the Ultrasound-assisted water-confined laser micromachining (UWLM) process (proposed by Prof. Benxin Wu), and (ii) the Dual-pulse laser ablation and plasma amplification (LAPA) process for drilling microholes with variable diameters at different depths (proposed by Prof. Yung C. Shin). The models are developed by numerically solving the relevant governing equations, and are tested by comparing with related experimental measurements when available. The specific topics that have been studied include: (i) Bubble evolution close to a solid boundary; (ii) Ultrasound propagation and cavitation in water; (iii) Laser amplification of pre-existing plasma in a microhole and plasma interaction with the hole sidewall.
Ph.D. in Mechanical and Aerospace Engineering, May 2017
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Title: EFFICIENCY OF PATENT CONTRACTS
Creator: Liang, Shao-huai
Date: 2014, 2014-05
Description: This thesis attempts to analyze the incentive compatible (IC) region for the royalty contract in an innovation context. It also describes the...
Show moreThis thesis attempts to analyze the incentive compatible (IC) region for the royalty contract in an innovation context. It also describes the contracts that induce the licensee and the patentee to obtain the maximum pro t when using this licensing contract. We analyze the IC region for cost-reducing innovations " and royalty ratios in two situations: the non-drastic innovation and the drastic innovation. We also nd when licensing occurs, there is an e ciency loss. However, the IC region can limit the e ciency loss. Then, we extend our results to a two-stage game in order to check whether the royalty contract is still a good contract for both the licensee and the patentee from a pro t perspective. In stage two, when the size of innovation is smaller than the size of innovation in stage one, royalty contracts are inferior to other contracts. However, when the size of innovation in stage two is greater than that in stage one, the royalty contract is an improvement over other contracts.
PH.D in Management Science, May 2014
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Title: ESSAYS ON DISTRIBUTIONALLY ROBUST PORTFOLIO OPTIMIZATION
Creator: Ousawat, Thitapon
Date: 2013, 2013-07
Description: Interest in distributionally robust optimization has been increasing recently. In this dissertation, we review recent developments in the...
Show moreInterest in distributionally robust optimization has been increasing recently. In this dissertation, we review recent developments in the literature in this eld and propose a model for distributionally robust mean-risk portfolio optimization. The model optimizes a risk-averse objective function with the worst-case return as reward and worse-case conditional Value-at-Risk as the risk measure. The model considers ambiguity in the distribution of data used to estimate the asset returns in the optimization model by creating an ambiguity set using -divergence measures which measure the distance between vectors. A numerical example is shown using the Kullback-Leibler divergence measure as the -divergence measure. A model for distributionally robust portfolio optimization with transaction costs is used to compare the performance of a distributionally robust mean-CVaR portfolio with the nominal as well as equally-weighted portfolio. The result shows that, under certain conditions, the distributionally robust model performs better than both the nominal and equally-weighted portfolio.
PH.D in Management Science, July 2013
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Title: EFFECTS OF DIFFERENT WRITTEN DISCLOSURE INTERVENTIONS AND THE MECHANISMS OF ACTION RESPONSIBLE FOR REDUCING MALADAPTIVE RUMINATION AMONG BROODERS
Creator: Coyle, Cynthia Weinstein
Date: 2013, 2013-07
Description: Brooding is a maladaptive form of rumination associated with negative bias, emotion dysregulation, ineffective problem solving, and depression...
Show moreBrooding is a maladaptive form of rumination associated with negative bias, emotion dysregulation, ineffective problem solving, and depression (Nolen-Hoeksema, 1991; Treynor, Gonzalez, & Nolen-Hoeksema, 2003). Some data indicate that writing interventions reduce brooding (Gortner, Rude & Pennebaker, 2006). What is less known are the mechanisms whereby writing counteracts brooding. The primary aim of this study was: (1) to examine the effects of writing conditions on functioning in brooders and (2) to provide empirical support for the mechanisms of action for how writing reduces brooding. Those who wrote from specific instructions were hypothesized to increase their cognitive appraisal, emotion regulation, and problem-solving abilities, thereby reducing brooding more than those writing from expressive writing and control group instructions. Writing also was hypothesized to reduce brooding through these mechanisms. Gaining a greater understanding of which writing techniques were most effective in reducing brooding and of how brooding is reduced is important for rumination research and therapeutic practice. Eighty-eight adults recruited from a mid-western university and the general population were divided into two experimental conditions (Expressive Writing (EW) and Self-Regulation/Problem-Solving (SR/PS) and one control group. A 3 X 2 MANOVA was conducted to determine whether improvements after the writing intervention were (a) greater in the EW and SR/PS conditions than in the control condition and (b) greater in the SR/PS condition than in the EW condition. A 3 X 2 MANOVA also was conducted to determine whether there were reductions in negative cognitive word use over time. Participants completed a survey of their subjective experience at the end of the study. ix Contrary to predictions, none of the hypotheses were supported. Improvements were not greater in either experimental group compared to the control group or in the SR/PS condition compared to the EW on any of the outcome variables. Only the use of anger words was significantly reduced over time. Given there were no significant reductions in brooding and no relationship between the predictor and outcome variables, a mediation analyses was not conducted. In contrast, subjective reports indicated that participants in the experimental conditions perceived the study to have greater meaning and felt happier after the study compared to the control group. Participants also reported improved emotion regulation, cognitive processing and problem-solving abilities. The findings suggest considering of an individual’s perception of treatment benefits when determining effectiveness.
PH.D in Psychology, July 2013
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Title: MULTI-DISCIPLINARY PERFORMANCE-BASED FORM GENERATION PROCESS: DEVELOPING AN OPTIMIZATION APPROACH FOR LONG SPAN ROOFS
Creator: Nicknam, Mahsa
Date: 2013, 2013-05
Description: This research is intended to incorporate multiple performances into the architectural form generation process of long span roofs. To this end,...
Show moreThis research is intended to incorporate multiple performances into the architectural form generation process of long span roofs. To this end, it proposes a multidisciplinary performance-based form generation process (MPGP) using Genetic Algorithm (GA) for the exploration of form based on performance criteria. This process leads us to a new integrated design approach in architecture. Conceptual design decisions have the greatest impact on building performance. However in conventional linear approaches, energy and structural issues are typically dealt with after these program, massing, and enclosure decisions are well articulated. This locks in life-cycle performance, and leads to costly redesigns when results fail to satisfy requirements. Research has shown how successful buildings emerge from the rapid and systematic generation and multidisciplinary analysis of many alternatives. However, until recently Architecture, Engineering and Construction (AEC) design teams were constrained by tools and schedule and only be able to generate a few alternatives, and analyze these from just a few perspectives. The rapid emergence of parametric and generative design, building simulation, and design space exploration and optimization tools now make it possible for a design team to construct and analyze far larger design spaces more quickly, and better understand the importance of design variables on the overall building performance. The proposed process, moves beyond the current form generation approaches by using the dynamic potential possibilities of simulation tools in which form generation is based on their performance feedback. The simultaneous integration of multiple xvi performances at the early stage of design minimizes the need to move back and forth later on the design development phase, therefore reducing the overall design circle. MPGP uses the potential of parametric algorithm to generate the form and uses an optimization algorithm, Genetic Algorithms (GAs), as a search algorithm to explore the proper design satisfying required performances. This method will demonstrate how a flexible 3D model can be parametrically altered toward targeted solutions with the help of near real-time feedback generated by performance-based analysis tools within an optimization framework. Hence, in this approach, design is considered to be a process of a repeated loop of generation, evaluation, and modification until the targeted objectives are satisfied. The integration of generative tools and performance analytical tools in the early stage of design provides great opportunities for the designers to enhance the design space and select the proper design among different design solutions based on their preferences. As a result, designers develop architectural forms based on informed decisions by observing the impact of the varying parameters on the structural and energy efficiency performances. Consequently, this process will greatly benefit engineering by achieving a more collaborative and information-based design environment. Increasing the number of efficient design alternatives, dealing with different levels of complexity in the architectural design process, promoting multi-disciplinary collaboration, and improving overall design understanding are the main benefits of the proposed process.
PH.D in Architecture, May 2013
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Title: XAFS STUDIES OF RADIATION DAMAGE IN NUCLEAR MATERIALS
Creator: Olive, Daniel Thomas
Date: 2012-11-13, 2012-12
Description: The growing demand for nuclear energy places a high importance on the development of new materials capable of withstanding higher temperatures...
Show moreThe growing demand for nuclear energy places a high importance on the development of new materials capable of withstanding higher temperatures and harsher irradiation conditions than those used in existing reactors. By supporting the development of next generation reactors it also becomes possible to close the nuclear fuel cycle, greatly reducing the amount of waste sent for disposal in deep geologic repositories, where its interaction with the environment is also a matter of interest. In this thesis, X-ray absorption fine structure (XAFS) spectroscopy is used to investigate the local atomic structure of systems of interest to nuclear energy. First, two XAFS studies on environmental materials are presented. Granular activated carbon (GAC) was treated with iron to improve its water remediation properties, specifically with respect to arsenic. XAFS was used to determine the nature of iron coating on the GAC surface, and the method of arsenic bonding to the treated surface. Next, a neodymium precipitate from solubility studies carried out for the Waste Isolation Pilot Plant (WIPP) was analyzed. Neodymium was used as an analog for plutonium in brine solutions. XAFS fitting indicated that the neodymium substituted for calcium in a gypsum lattice, providing information useful for future geochemical modeling. XAFS was also used to study radiation damage in materials. A candidate material for advanced reactor structural materials, modified 9Cr–1Mo, was irradiated to 1, 4, and 10 displacements per atom (dpa). XAFS analyses were performed on the Fe, Mo, and Nb K-edges. Irradiation caused a reduction in coordination for all three elements, but the exact behavior was element specific. Damage around Fe atoms was linear with dose, while damage around xxii Mo atoms saturated at or before 1 dpa. XAFS was shown to provide a useful atomic level description of radiation damage for a complex alloy system. Finally, zirconium carbide and zirconium nitride, candidate materials for advanced fuel claddings were studied at the Zr K-edge. Samples irradiated to 1 dpa retained overall crystallinity, as indicated by transmission electron microscopy (TEM) images but were found to have an increase in dislocation loops compared to their non-irradiated counterparts. XAFS analysis was able to determine the size of the undefected regions, making it a valuable complement to other analysis techniques. xxiii
PH.D in Physics, December 2012
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Title: PRE-CLINICAL IN VIVO AND IN VITRO ASSESSMENT OF HEMOSTATIC EFFECTS OF CONTINUOUS-FLOW VENTRICULAR ASSIST DEVICES
Creator: Crandall, Daniel
Date: 2011-07, 2011-07
Description: Heart failure results in significant morbidity and mortality for those afflicted. The current gold standard treatment is allogenic heart...
Show moreHeart failure results in significant morbidity and mortality for those afflicted. The current gold standard treatment is allogenic heart transplantation, however insufficient supply of donor organs limits the effectiveness of this treatment to ideal candidates. This has led to interest in mechanical circulatory support. The most recent generation of devices are smaller, continuous-flow devices with increased durability compared to their predecessors. However, these new devices exhibit increased rates of hemostatic events – both thromboembolic and hemorrhagic. This thesis details an in vivo evaluation of hemostatic parameters in a bovine animal model to evaluate the effect of the ventricular assist device (VAD), and compares these results to what has been seen clinically. Most importantly this thesis has found that bovines do not experience pathophysiologic degradation of high molecular weight Von Willebrand Factor (VWF) as a result of VAD placement, whereas this complication is well documented in humans. This is due to a decreased sensitivity to shear stress induced cleavage of VWF in bovines when compared to humans, as demonstrated in this thesis. Due to the inability to replicate clinical conditions with the bovine animal model, this thesis develops an alternative methodology using an in vitro flow loop using the same human donor blood on all pumps tested. This methodology eliminates the need for interspecies extrapolation; allows for more direct comparisons by eliminating donor variation; and is both cheaper and faster than animal models. This methodology could provide an invaluable option for evaluating hemostatic effects of various pump design parameters.
Ph.D. in Biomedical Engineering, July 2011
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