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Title: Investigation of Retinal Hemodynamics in a Diabetic Animal Model and VEGF Induced Animal Model
Creator: Turturro, Sanja
Date: 2011-05-11, 2011-05
Description: Diabetic retinopathy (DR) is a complication of diabetes that can ultimately lead to vision loss. Early changes of DR include leukocyte...
Show moreDiabetic retinopathy (DR) is a complication of diabetes that can ultimately lead to vision loss. Early changes of DR include leukocyte adhesion, pericyte loss, and alterations in retinal blood flow. These changes typically occur prior to clinical diagnosis and can develop into more severe problems such as neovascularization and angiogenesis. The objective of the current study was to investigate retinal hemodynamics in early stages of DR in a diabetic animal model and to evaluate the effect of insulin therapy on retinal hemodynamics in diabetic rats in order to demonstrate how controlled blood glucose levels may regulate changes in vasculature. Lastly, the role of vascular endothelial growth factor (VEGF) on retinal hemodynamics of a normal animal were studied to determine the effects of elevated levels of VEGF on retinal vasculature. Volumetric blood flow (VBF) was quantified using average blood velocity and average diameter measured by using the scanning laser ophthalmoscope (SLO) and the particle tracking method. Pericyte coverage was also quantified with a whole-mount retina technique. In diabetic rats, it was shown that arterial and venous VBF decreased beginning at two weeks post onset of diabetes and continued to decrease throughout the eight week time period. There was no significant loss of pericytes at the eight week time point, however, structural abnormalities were observed at the capillary level. Following insulin therapy, the VBF values of treated diabetic animals were comparable to normal animal VBF values and insulin therapy seemed to normalize VBF of diabetic animals. Exogenous levels of VEGF in normal animals showed significant changes in retinal hemodynamics and vasculature. Future experiments should include investigation of factors that may alter retinal blood flow and quantification of VEGF levels in diabetic animals.
Ph.D. in Biomedical Engineering, May 2011
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Title: SYNTHESIS AND INVESTIGATION OF NOVEL CATHODE MATERIALS FOR SODIUM ION BATTERIES
Creator: Sawicki, Monica
Date: 2015, 2015-12
Description: Environmental pollution and eventual depletion of fossil fuels and lithium has increased the need for research towards alternative electrical...
Show moreEnvironmental pollution and eventual depletion of fossil fuels and lithium has increased the need for research towards alternative electrical energy storage systems. In this context, research in sodium ion batteries (NIBs) has become more prevalent since the price in lithium has increased due to its demand and reserve location. Sodium is an abundant resource that is low cost, and safe; plus its chemical properties are similar to that of Li which makes the transition into using Na chemistry for ion battery systems feasible. In this study, we report the effects of processing conditions on the electrochemical properties of Na-ion batteries made of the NaCrO2 cathode. NaCrO2 is synthesized via solid state reactions. The as-synthesized powder is then subjected to high-energy ball milling under different conditions which reduces particle size drastically and causes significant degradation of the specific capacity for NaCrO2. X-ray diffraction reveals that the lattice distortion has taken place during high-energy ball milling and in turn affects the electrochemical performance of the cathode material. This study shows that a balance between reducing particle size and maintaining the layered structure is essential to obtain high specific capacity for the NaCrO2 cathode. In light of the requirements for grid scale energy storage: ultra-long cycle life (>20,000 cycles and calendar life of 15 to 20 years), high round trip efficiency (> 90%), low cost, sufficient power capability, and safety; the need for a suitable cathode materials with excellent capacity retention such as Na2MnFe(CN)6 and K2MnFe(CN)6 will be investigated. Prussian blue (A[FeIIIFeII (CN)6]•xH2O, A=Na+ or K+) and its analogues have been investigated as an alkali ion host for use as a cathode material. Their structure (FCC) provides large ionic channels along the <100> direction enabling facile insertion and extraction of alkali ions. This material is also capable of more than one Na ion insertion per unit formula which holds great promise in increasing the energy density of the NIB. The electrochemical performance of the cathode material will be analyzed using cyclic voltammetry, and galvanostatic charge/discharge investigation.
Ph.D. in Materials Science and Engineering, December 2015
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Title: INVESTIGATION OF THE OXYGEN REDUCTION REACTION AT THE LITHIUM-OXYGEN CELL CATHODE
Creator: Sankarasubramanian, Shrihari
Date: 2016, 2016-12
Description: Development of Li-O2 cells, which could possibly provide ~3 times the capacity of conventional Li-ion cells, depends on a fundamental...
Show moreDevelopment of Li-O2 cells, which could possibly provide ~3 times the capacity of conventional Li-ion cells, depends on a fundamental understanding the oxygen reduction reaction (ORR) at the cathode. This abstract summarizes the application of ab initio density functional theory (DFT) calculations and electrochemical measurements in conjunction with kinetic modeling to elucidate the mechanism of the ORR in the Li-O2 cell. First principles, density functional theory (DFT) modeling of the ORR on noble metal (Pt, Au, Pd), Pt3M (M=Fe, Co, Ni, Cu) and Pd3M (M=Fe, Co, Ni, Cu) alloy surfaces, was carried out. Periodic models of close-packed (111) surfaces were constructed, their geometry was optimized and the most stable geometric surface configuration was identified. The correlation between the intermediate species binding energy and the favored reaction pathway from amongst 1e-, 2e-, and 4e- mechanisms was studied by calculating the binding energies of a 1/4 monolayer of O, O2, LiO, LiO2, Li2O2, and Li2O on various sites and orientations. The reaction free energies (ΔGrxn) were calculated and used to compute the catalytic activity of the surfaces using molecular kinetics theory. Plots of the catalytic activity vs. Oxygen binding energy (EBinding (O)) showed a typical “volcano” profile. The insights gained from this study can be used to guide the choice of cathode catalysts in Li-O2 cells. The mechanism and kinetics of the ORR was investigated in 0.1M LiTFSI/DME on a glassy carbon (GC) electrode in an oxygen saturated solution of 0.1M Lithium bis-trifluoromethanesulfonimidate (LiTFSI) in Dimethoxyethane (DME) using cyclic voltammetery (CV) and the rotating ring-disk electrode (RRDE) technique. A comprehensive reaction scheme considering disproportionation both on the cathode surface and the electrolyte bulk to form Li2O2 was proposed and the data from the RRDE measurements was used along with an electrochemical kinetics model to evaluate the corresponding rate constants. The surface disproportionation reaction was found to dominate the kinetics of the ORR and the model was found to be able to explain experimental observations regarding the cell discharge products. Further, the widely reported anomalous Tafel behavior was observed over the course of these studies. Highly accurate, potentiostatic, point-by-point measurements of the kinetic current were carried out and a scan rate independent evaluation of the corresponding transfer coefficient from a calculated, dimensionless CV was made. The measured transfer coefficient was explained invoking the Marcus-Hush-Levich quadratic model rather than the linearized Butler-Volmer empirical law. Thus, these studies provides a comprehensive account of the ORR mechanism, direct evidence of the surface disproportionation reaction being dominant and explain the widely reported (and previously unexplained) anomalous Tafel behavior in Li-O2 cells.
Ph.D. in Chemical Engineering, December 2016
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Title: PRFA-LIKE TRANSCRIPTION FACTOR, LMO0753, CONTRIBUTES TO VIRULENCE, L-RHAMNOSE UTILIZATION, AND PERSISTENCE OF LISTERIA MONOCYTOGENES HUMAN FOODBORNE OUTBREAK LINEAGES
Creator: Salazar, Joelle Krieger
Date: 2013, 2013-12
Description: Listeria monocytogenes is a foodborne bacterial pathogen and the causative agent of a human and animal disease, listeriosis. Among the three...
Show moreListeria monocytogenes is a foodborne bacterial pathogen and the causative agent of a human and animal disease, listeriosis. Among the three major genetic lineages of L. monocytogenes (i.e. LI, LII, and LIII), LI and LII are predominantly associated with foodborne listeriosis outbreaks, whereas LIII is rarely implicated in human infections. In a previous study, we identified a Crp/Fnr family transcription factor lmo0753 that was highly specific to outbreak-associated LI and LII but absent from LIII. Lmo0753 shares two conserved functional domains including a DNA-binding domain with the well-characterized master virulence regulator PrfA in L. monocytogenes. In this study, lmo0753 deletion and complementation mutants were constructed in two fully sequenced L. monocytogenes LII strains 10403S and EGDe, and compared virulence-associated mechanisms of flagellar motility, phospholipase C production, hemolysis, and intracellular growth of the mutants and their respective wild types. Persistence-associated mechanisms of growth, biofilm production, attachment and soil survival were also assayed. Results suggested that lmo0753 plays a role in some virulence- and persistence-associated mechanisms in both EGDe and 10403S. More importantly, it was found that deletion of lmo0753 led to the loss of L-rhamnose utilization in EGDe but not in 10403S. Transcriptomic comparison of the EGDe lmo0753 deletion mutant and the wild type incubated in Phenol-red medium containing L-rhamnose as the sole carbon source revealed 126 (4.5%) and 546 (19.5%) out of 2,798 genes in the EGDe genome that were up- and down-regulated for more than 2-fold, respectively. Genes involved in biotin biosynthesis, general stress response and rhamnose metabolism were shown to be differentially regulated by Lmo0753. Findings from this study may partially explain why xvi LIII of L. monocytogenes is underrepresented in the environment and rarely associated with human listeriosis outbreaks due to the inability of rhamnose utilization.
PH.D in Biology, December 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: HEURISTIC DECISION-MAKING MODEL FOR ELECTRICAL FOREMEN WHEN WORKFLOW IS DISRUPTED
Creator: Pandey, Arjun R.
Date: 2016, 2016-05
Description: The decision-making process used by construction foremen at a job site when the workflow is disrupted was investigated in this study. The...
Show moreThe decision-making process used by construction foremen at a job site when the workflow is disrupted was investigated in this study. The foremen’s decision-making process was mapped and then modeled to a heuristic model. This study focuses on cognitive decision or psychological heuristic models. The study shows that construction foremen use a heuristic decision model in their decision-making. The capability of heuristic to yield fast decision is very useful in construction because it is common for a construction foreman to experience several disruptions during the course of a single workday. With heuristic decision-making, a work-around decision can be rapidly and effectively made following a construction site disruption. Understanding the ability of heuristics to facilitate rapid and effective decision-making will help the construction industry to save time and increase productivity. Research was conducted in order to map a decision process that foremen were using in their decision-making and to develop a model for a heuristic decision-making process. Interviews were conducted with 22 construction foremen in the electrical trade in 88 real disruption cases in order to understand how decisions were made after disruptions occurred. Interviews were subsequently conducted with 10 additional industry foremen in 10 real disruption cases to validate the data. Using this data, a heuristic decision-making model was developed. To validate this model, a survey was conducted with another 11 industry foremen. The findings indicate that construction foremen currently use a heuristic decision-making model known as “determinant decision attribute” (referred to as DDA) heuristics model. This DDA heuristic model was compared to the similar model with equal weighing and elimination by aspects (referred to as EW/EBA) to assess the performance of the heuristic. The DDA heuristic model correctly predicted, on average, 91% of the time what foremen’s decisions were as to which decision task to choose to assign or re-assign to crew members. Whereas, the EW/EBA model correctly predicted, on average, 82% of the time, the foremen’s decisions. A computer program was also developed for DDA heuristic model to help foremen expedite the process of their decision-making.
Ph.D. in Civil Engineering, May 2016
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Title: CONTROLLED AND EXTENDED RELEASE OF ANTIANGIOGENIC AGENTS FOR THE ENHANCED TREATMENT OF CHOROIDAL NEOVASCULARIZATION
Creator: Osswald, Christian R.
Date: 2015, 2015-07
Description: Current U.S. Food and Drug Administration (FDA)-approved drug therapies for choroidal neovascularization (CNV) secondary to age-related...
Show moreCurrent U.S. Food and Drug Administration (FDA)-approved drug therapies for choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD), also known as wet AMD, require monthly or bimonthly intravitreal (IVT) injections of bolus antiangiogenic agents such as anti-vascular endothelial growth factors (anti-VEGFs) [1]. Less-frequent administration of anti-VEGFs via controlled and extended release is needed to lower the socio-economic impact and lessen the potential side-effects associated with frequent IVT injections. While a controlled delivery system is beneficial, the challenges of initial burst (IB), maintenance of drug bioactivity, and understanding the drug distribution in the diseased eye must be addressed to design an optimal system to address this need. The main goal of this study was to develop a drug delivery system (DDS) capable of delivering anti-VEGF for six months. Additionally, we propose that controlled and extended release of anti-VEGF will yield a greater reduction in CNV growth compared to bolus administration of the same drug. Thus, the current monthly/bimonthly treatment regimen could be replaced by, say, a semi-annual treatment. To accomplish this goal, three specific aims were performed: 1) Development of an injectable microsphere-hydrogel DDS with minimal IB and prolonged release of bioactive anti-VEGF; 2) Verification and validation of the efficacy of said DDS in vivo; and 3) A proof-of-concept finite element analysis comparing the drug distribution throughout a diseased eye to that of a healthy eye.
Ph.D. in Biomedical Engineering, July 2015
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Title: EVALUATION OF COMPUTER ALGORITHMS FOR THE ANALYSIS AND RECONSTRUCTION OF CARDIAC IMAGES
Creator: Parages, Felipe M.
Date: 2017, 2017-05
Description: In the medical imaging field, image processing algorithms must be evaluated by measuring performance at some clinically-relevant task of...
Show moreIn the medical imaging field, image processing algorithms must be evaluated by measuring performance at some clinically-relevant task of interest (i.e. task-based quality assessment). This dissertation relies on the task-based paradigm to evaluate motion-estimation and image-reconstruction methods, respectively, for two cardiac-imaging modalities, namely: cardiac-gated tagged Magnetic Resonance Imaging (MRI), and Single Photon Emission Computerized Tomography for Myocardial Perfusion Imaging (SPECT-MPI). First, a task-based approach is followed to evaluate three motion-estimation methods for clinical cardiac-gated tagged MRI, namely: non-rigid registration using a Deformable Mesh Model (DMM), Strain from Unwrapped Harmonic Phase (SUPHARP), and Feature-Based (FB) algorithms. More specifically, the goal is to quantify and rank their performances at both detection and estimation tasks. For detection, methods are evaluated per their ability to discern between normal and abnormal motion patterns in known cardiomyopathies (e.g. hypertension and mitral regurgitation). For estimation tasks, methods are evaluated per their accuracy at estimating several rotation/twist and strain features of clinical interest; since true values for these features are generally unknown, a statistical Regression Without Truth (RWT) model is adopted, which does not assume the existence of a “gold-standard” method to use as a ground-truth reference. Moreover, the RWT model provides with an objective figure-of-merit that allows ranking methods in absolute fashion. Second, a novel anthropomorphic Model Observer (MO) is proposed for optimization of SPECT-MPI reconstruction algorithms such as Filtered Back-projection (FBP) and Ordered-subsets Expectation Maximization (OSEM). MOs are computer models that aim to mimic the performance of human readers (typically radiologists) at some clinically relevant task of interest. The proposed MO is based on supervised machine-learning classification, for the diagnostic tasks of detection, localization and assessment of perfusion defects. The MO is trained using an ensemble of synthetic cases whose perfusion were scored (i.e. labeled) by human specialists. The trained MO is subsequently applied on images not read by humans (both synthetic and clinical), aiming to predict their diagnostic scores. Results show that the proposed MO accurately predicts human diagnostic performances. Furthermore, it generalizes well to new images not used during training, not only from different reconstruction algorithms, but also from synthetic to clinical cases.
Ph.D. in Electrical and Computer Engineering, May 2017
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Title: SYNERGETIC COMPUTATIONAL AND EXPERIMENTAL STUDIES OF WALL-BOUNDED TURBULENT FLOWS AND THEIR TWO-DIMENTIONALITY
Creator: Vinuesa, Ricardo
Date: 2013, 2013-05
Description: N/A
PH.D in Mechanical and Aerospace Engineering, May 2013

Title: GENDER DIFFERENCES IN POSTCONCUSSIVE SYMPTOMS OF SPORT-RELATED CONCUSSIONS IN CHILDREN AND ADOLESCENTS
Creator: Gretencord Roy, Ashley Aline
Date: 2016, 2016-07
Description: Current research on concussions indicates that both younger age and female gender are associated with a greater number of symptoms and a...
Show moreCurrent research on concussions indicates that both younger age and female gender are associated with a greater number of symptoms and a lengthier postconcussive recovery time. The aim of this research was to examine postconcussive symptoms (PCS) resulting from a sports-related concussion in both male and female children/adolescents. Data was collected using neuropsychology measures (Auditory Consonant Trigrams Test, Conners' Continuous Performance Test-2nd edition, Immediate Post-Concussion Assessment and Cognitive Testing, Woodcock Johnson Tests of Achievement- Third Edition, and Behavior Assessment System for Children-2nd edition) and a neurological evaluation. Participants included 132 children/adolescents (10-18 years) who had sustained a sports-related concussion. Results indicated evidence of subtle, but clinically significant, impairments in executive functioning. This was particularly true for those with a premorbid attention, learning, and/or mood disorder. In addition, a history of previous concussions was associated with a higher number of reported cognitive PCS. Hierarchical regression analyses were conducted for each of the dependent measures. As predicted, female gender was associated with increased executive dysfunction and a higher report of cognitive and emotional/behavioral PCS. Contrary to hypotheses, younger age was associated with less executive dysfunction and fewer reported cognitive PCS. No interaction between age and gender was identified. Implications of the findings are discussed.
Ph.D. in Psychology, July 2016
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Title: MOTIVES FOR SOCIAL MEDIA USE AMONG PRACTITIONERS AT NONPROFIT ORGANIZATIONS
Creator: Roback, Andrew J.
Date: 2017, 2017-05
Description: I used the motivation concept from activity theory to derive a fundamental notion of why workers at nonprofit organizations (NPOs) use social...
Show moreI used the motivation concept from activity theory to derive a fundamental notion of why workers at nonprofit organizations (NPOs) use social media sites. This study rejects the notion that practitioners are not taking full advantage of social media sites by not using every available feature and engaging in dialogic communication. Existing work relies too extensively on the dialogic model of communication and frequently focuses on only top-tier NPOs, ignoring the context in which smaller NPOs operate and producing recommendations that are of little practical value. To investigate this issue, I reviewed existing best practices as portrayed in NPO social media strategy guides, and used the principles of activity theory to survey practitioners at human services NPOs in Chicago. I collected data on user motivation for using Facebook and Twitter by asking users to review past posts on these sites and describe their purpose in posting this information. Using this information, I trained an automated text classifier to classify a large corpus of posts based on four types of motivations: soliciting, promoting, sharing, and credit-giving. This dissertation builds off recent studies that question existing wisdom on “effective” use of social media by NPOs and argues for an expanded consideration of user agency and intent when using social media.
Ph.D. in Technical Communication, May 2017
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Title: THE BUSINESS CYCLE, FORECAST HORIZONS AND STOCK RETURN PREDICTABILITY
Creator: Irons, Robert
Date: 2012-12-04, 2012-12
Description: This paper investigates the impact of the business cycle when forecasting equity returns over different forecast horizons. Weigand and Irons ...
Show moreThis paper investigates the impact of the business cycle when forecasting equity returns over different forecast horizons. Weigand and Irons [2007] show that relative valuation matters when forecasting long-term returns to the market, a conclusion that is verified in this study with reference to the period 1934-1949. This study reveals that the business cycle matters when forecasting short-term (one year or less) market returns, over the entire period of study (1934-1999). An econometric issue first noted in Weigand and Irons [2008] is verified and pinpointed more precisely in time, to the year 1950. The market earnings yield (the inverse of the market P/E ratio), one of the foremost predictors of future market returns, is shown to be ineffective in forecasting returns over any forecast horizon in the second half of the 20th century. This result is further evidence of the impact of investors' belief in the Fed Model, which equates the yields on bonds to the returns on stocks. The term spread of interest rates, one of the business cycle proxies used in this paper, is shown to have a significant impact when forecasting market returns over any horizon during the period 1950-1999, which is consistent with the Fed Model.
PH.D in Management Science, December 2012
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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: AN EMPIRICAL GROUNDED THEORY APPROACH TO CHARACTERIZING ADVANCED MATHEMATICAL THINKING IN COLLEGE CALCULUS
Creator: Nabb, Keith A.
Date: 2013, 2013-07
Description: The research literature has made calls for greater coherence and consistency with regard to the meaning and use of the term advanced...
Show moreThe research literature has made calls for greater coherence and consistency with regard to the meaning and use of the term advanced mathematical thinking (AMT) in mathematics education (Artigue, Batanero, & Kent, 2007; Selden & Selden, 2005). Educators and researchers agree that students should be engaged in AMT but it is unclear precisely what is meant by AMT or how these engagements may manifest themselves in student work. Moreover, many contributions are aimed at advancing theory with little effort to connect with classroom practice. The intent of this study was to examine individuals in their natural problem solving states and to empirically describe how AMT might unfold in the context of nonroutine calculus problems. The study was conducted during the spring semester of 2012. Thirteen students solved three nonroutine calculus problems, each loosely couched in theories of AMT—process-concept duality (Gray & Tall, 1994), epistemological obstacle (Bachelard, 1938; Harel & Sowder, 2005; Sierpińska, 1987), and the basic metaphor of infinity of mathematical idea analysis (Lakoff & Núñez, 2000). While empirical instances of these theories were present, students predominantly displayed idiosyncratic strategies by way of imposing mathematical/scientific objects, tools, or concepts on the local domain of the problem space. Efforts to first individualize the task were followed by completing the task through this individualization. Both successful and unsuccessful problem attempts were documented in the form of novel tool usage, visualization, and/or abstraction through communication. x The outcome of this study suggests a need to further examine students’ use of procedures and how students successfully anticipate the utility of these procedures. Additionally, further work is needed to explain both the elevated use of visualization and how/why discussions with others provide momentum for abstracting solutions to contradictory problems. With respect to classroom practice, students’ novel use of well-known mathematics mirrors the habits of research mathematicians in their professional work. Importing such uses into classroom discourse has the potential to deepen connections of mathematics content and to enrich mathematics experiences through nonstandard methods of problem solving.
PH.D in Mathematics Education, July 2013
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Title: SYNTHESIS AND STRUCTURAL INVESTIGATION OF POLYOXOVANADATE SYSTEMS FOR SEMICONDUCTOR NOx SENSING
Creator: Ravikanth Putrevu, Naga
Date: 2013, 2013-12
Description: Nitrogen oxides (NO and NO2 collectively termed as NOx) are the common air pollutants produced from various indoor and outdoor activities. It...
Show moreNitrogen oxides (NO and NO2 collectively termed as NOx) are the common air pollutants produced from various indoor and outdoor activities. It can cause several environmental problems like ground-level ozone, acid rain, particulate matter, smog formation and health problems like malfunctioning of lungs, damaging air flow passages and creating respiratory problems. To detect these gases, sensors with greater sensitivity, lower recovery time and longer life time are needed. Despite the advantages, of the most widely used NOx sensing materials, semiconducting metal oxides have the limitations like higher operating temperatures and unable to customize the materials with better sensitivity and selectivity. So the current research discusses about a new class of metal oxide systems called polyoxovanadates (POV) and its suitability for the ambient operating conditions. These POVs are basically the vanadium oxide clusters synthesized in top-down and bottom-up synthesis procedures. The main advantages of these systems are possible to synthesize in various sizes, shapes, geometries and dimensions which can help identifying the suitable material for a specific gas. The experimental part discusses about the synthesis, characterization and semiconducting sensing properties of different POV systems using various atomic and molecular spectroscopic techniques. In Chapter 2, a 3-D open framework polyoxovanadate material, [Cd3(H2O)12V16 IVV2 VO36(OH)6(AO4)]·24H2O, (A=V,S) (1), composed of secondary building blocks ({V18O42(AO4)} (A=V,S) clusters) interconnected by {-O-Cd-O-} bridging groups, was chosen for understanding the effect of atmospheric oxygen on 1 electronic properties like band gap and resistance, considering the oxygen as a common xiv interferent in ambient gas sensing. The results explain that 1 interacts with oxygen during the aging process and results changing the vanadium oxidation state from +4 to +5 and expanding the coordination sphere of vanadium from 5 to 6. This expansion can alter the band gap by overlapping the more number of O 2p orbitals with V 3d orbitals and resulting the decrease in resistance. The experiments conducted on molecular {V18O42(AO4)} (A=V,S) cluster, (NH4)8[VIV 12VV 6O42(SO4)]·10H2O, (2a), in Chapter 3, also shown the similar change in band gap and resistance during aging process. Based on the results obtained in Chapter 2 and Chapter 3, a {VO6} containing vanadium oxide cluster, (NH4)2[Ni(H2O)5(NH3)]2[V10O28]·4H2O (4), was synthesized and proved in Chapter 4, that the higher coordination number help lowering the band gap and the resistance without need of aging. In Chapter 5, the NOx sensing properties of 1, 2a, 3 and 4 were studied and compared with well studied NOx sensing material, WO3. Based on the sensing characteristics, 1 shows good sensitivity and response time towards both NO and NO2 under ambient conditions than all the other materials. The FTIR spectroscopy results indicated that the NO2 sensing mechanism occurs via nitrate formation.
PH.D in Chemistry, December 2013
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Title: Fabrication and Characterization of High Aspect Ratio Hard X-ray Zone Plates with Ultrananocrystalline Diamond Molds
Creator: Wojcik, Michael J.
Date: 2013, 2013-05
Description: Hard x-ray zone plate development has played an important role in improving x-ray microscopy through ner resolution and greater functional X...
Show moreHard x-ray zone plate development has played an important role in improving x-ray microscopy through ner resolution and greater functional X-ray energy. Similar to circular di raction gratings except with changing period as a function of radius, zone plates are di ractive focusing optics with resolution determined by the outer most zone width (OZW). Hard X-ray zone plates are mostly phase zone plates with a limited e ciency that peaks when the zone material causes a -phase shift on the x-ray, and the zone thickness required can be multiple microns dependent on x-ray energy. The combination of sub-100-nm resolution and peak e ciency for hard xrays requires very high aspect ratio zones. In this dissertation, two materials were used to fabricate high aspect ratio zone plates in a single layer mold and a two layer mold process. Ultrananocrystalline diamond (UNCD) is composed of 2-5 nm diamond grains bounded together with graphitic bonds. This form of diamond can be deposited onto substrates with thickness greater than a micron and with physical properties similar to bulk diamond. Hydrogen silsesquioxane (HSQ) is a spin on glass that is also a high contrast electron beam lithography resist. A thick layer of HSQ can be patterned into high aspect ratio structures and could be used as a pattern transfer mask for several etch recipes. Both of these materials were used to fabricate up to 25 aspect ratio zone plates and with OZW of 60 and 80 nm. Zone plates fabricated with UNCD were the rst high aspect ratio zone plates using a diamond like material and this technique was leveraged into a new fabrication method using two layers as an electroplating mold. Fabricated zone plates were characterized to measure the optical properties to compare with the fabrication properties. After characterization, several zone plate models based on fabricated zone plates were developed and simulated using a wave propagation technique to compare with the characterization data. The results xiii from fabrication, characterization, and simulation of zone plates with 25 aspect ratio will be presented as well as future possibilities for the techniques used.
PH.D in Physics, May 2013
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Title: BAYESIAN MOMENTUM STRATEGY OF EXCHANGE RATES
Creator: Lee, Namhoon
Date: 2011-11, 2011-12
Description: A disagreement has existed between the foreign currency trading community and academic researchers relating to the time series properties of...
Show moreA disagreement has existed between the foreign currency trading community and academic researchers relating to the time series properties of exchange rates. Traders typically view exchange rates as strongly trending prices and suggest that simple rules, based solely on past prices, have generated predictable profits with acceptable risk over most of the floating-rate period. However, many surveys presenting controversial results. This research identifies the non-linear trend momentum in monthly exchange rate and examines the profitability of momentum trading model within exchange rate returns in the context of Bayesian econometrics. A development of Bayesian momentum trading strategy based on trend component of the spot exchange rate is established. First, parameters of momentum model for each main currency are estimated. The momentum is defined as a simple nonlinear function of return series and the model is designed to estimate the expected conditional mean and associated conditional volatilities simultaneously. The empirical results reported several notable confirmation and findings; first, predictability of momentum model with Bayesian approach show better accuracy than model with maximum likelihood estimation or moving average rule in terms of directionality and model fitting. Second, parameters are restricted to be same across the currencies with the assumption that currencies share some degree of commonality within the system. The result confirms that the restricted model work as well as the unrestricted model within the currency model in terms of model fitting and directional accuracy. Third, principal component analysis is used to analyze the exchange rate movements. PCA found that the first principal component shows parallel shift of all currencies and second principal component tilt shift where high yield currencies move down and low yield currencies move up. Fourth, the parameter estimates from the models are used for portfolio allocation ix applying Bayesian Principal Component(PC) GARCH(1,1) model and the portfolio performance is compared with the performance with classical maximum likelihood approach and other benchmarks. The results show that the Bayesian PC-GARCH(1,1) performs better than classical PC-GARCH(1,1) in terms of Sharpe ratio, Value at Risk, Expected shortfall, maximum drawdown and other statistical criteria. Sixth, the GARCH parameter space is found to be non-symmetric confirming that maximum likelihood estimation would have over or under estimated the parameter causing misspecifying the model parameters. The result from this research confirms simple nonlinear momentum model combined with Bayesian approach can be a good forecasting tool, and restricted model can simplify the complexity of parameter space of exchange rate movement. In addition, by correctly detecting the parameter space, Bayesian approach outperforms the classical maximum likelihood approach. Keywords : Bayesian framework, Momentum, Moving Average rules, Carry trade strategy, Mean-variance Optimization, Trading strategy, Metropolis-Hastings Algorithm, Gibbs Sampler
Ph.D. in Management Science, December 2011
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Title: NEW CLASS OF EMBEDDED SPACE TIME BLOCK CODE FOR MIMO WIRELESS COMMUNICATION SYSTEMS
Creator: Norouzi, Mandana
Date: 2015, 2015-12
Description: In this thesis a new class of space time block codes is proposed. Space time code is one solution for the multipath fading communication...
Show moreIn this thesis a new class of space time block codes is proposed. Space time code is one solution for the multipath fading communication systems that limit the reliability and data rate of the communication link. By organizing multiple antennas at the transmitter and receiver, multipath fading can be turned into an advantage, allowing for greater reliability and higher data rates than would otherwise be possible. Without any extra cost of bandwidth, rate and reliability benefits can be achieved. Therefore, having multiple antenna technology is a foundation of current and future wireless systems. In space time coding information, symbols are encoded across two dimensions, the spatial dimension and the time dimension. Information that is transmitted corresponds to multiple antennas at the transmitter and to multiple signaling intervals. In this thesis, we consider the problem of designing a new class of linear space time block codes, in which the information symbols are linearly combined to form a twodimensional code matrix, wherein the rows of the code word matrix correspond to transmission across multiple antennas, and the columns of the matrix correspond to transmission in different time slots. The proposed space time code matrix is achieved based on eigenvalue decomposition (EVD) of the circulant, normal matrix and inverse fast Fourier transform definition (IFFT). These classes of codes have better performance with respect to symbolerror rate (SER) in comparison with other proposed linear space time code matrices in the literature. The proposed code has full rate and embedded diversity. The concept of embedded diversity has been defined in this research. According to that definition ourdesign supports embedded diversity and also has less decoding complexity at the receiver side. The proposed code has been applied to a relay network where nodes do not have four transmit antennas. In this thesis, performance of the code has also been evaluated when the receiver must rely on a noisy, imperfect, estimate of the channel. Channel estimation has been applied based on pilot sequence transmission. A group decodable full rate and full diversity space time block code also has been proposed for two transmit antennas and four time slots, which is applicable to the LTE-Advanced system. This new design also provides full diversity and full rate.
Ph.D. in Electrical Engineering, December 2015
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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: RADAR AND COMMUNICATION CO-DESIGN: A CONSTANT ENVELOPE RADCOM SYSTEM
Creator: Testi, Nicolo
Date: 2014, 2014-12
Description: NO ABSTRACT
Ph.D. in Electrical and Computer Engineering, December 2014

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