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Title: Predictive Energy Management of Connected Hybrid Electric Vehicles in the Presence of Uncertainty
Creator: Sotoudeh, Seyedeh Mahsa
Date: 2022
Description: Energy efficiency improvements brought by electrification of the powertrain in Hybrid Electric Vehicles (HEVs) highly depend on their...
Show moreEnergy efficiency improvements brought by electrification of the powertrain in Hybrid Electric Vehicles (HEVs) highly depend on their powertrain Energy Management Strategy (EMS) that determines optimal power allocation between powertrain components.Eco-driving based EMS seeks further energy efficiency improvements through optimizing vehicle's driving cycle (velocity and hence torque demand), in addition to the powertrain's EMS. A novel hierarchical EMS is developed in this thesis for connected human-driven HEVs and then extended to automated HEVs that effectively addresses some of the major challenges of the energy management problem. At its high-level, a computationally-tractable Pseudospectral Optimal Controller (PSOC) with discounted cost is employed to approximately solve the powertrain's energy management problem over driving cycle previews of the entire trip. The high-level's approximate solution is then used as a reference by the low-level tube-based Model Predictive Controller (MPC) that solves the problem over higher-quality, short-horizon driving cycles in a real-time applicable fashion. For human-driven HEVs, a Long Short-Term Memory (LSTM) neural network predicts the human driver's velocity profile over low-level's short horizons. A velocity optimizer is added to the low-level for automated HEVs that optimizes the vehicle's driving cycle by effectively utilizing regenerative braking capability of the HEV. At the low-level, the tube-based MPC controller solves the powertrain's energy management problem over either predicted (human-driven HEV) or optimized (automated HEV) driving cycles by accounting for driving cycle's uncertainty, due to uncertain future information, and hence ensures robust constraints satisfaction. A novel cost-to-go approximation method is developed that uses the optimal costate trajectories obtained from the high-level PSOC controller to generate terminal costs for the low-level controller. This improves suboptimality of the short-horizon solutions and ensures charge balance constraint satisfaction at the end of the trip without having to impose conservative constraints. A novel learning-based framework is also proposed to jointly optimize the automated HEV's driving cycle and its powertrain's power split. A Deep Neural Network (DNN)-based MPC controller is developed for the low-level that jointly optimizes the HEV's driving cycle and powertrain energy management in a real-time applicable manner. To ensure constraints satisfaction, a novel Quadratic Programming (QP)-based projection of the DNN-based approximate control laws is proposed that can be efficiently solved in real-time. Simulation results over standard and real-world driving cycles demonstrate efficacy of the proposed control frameworks in terms of suboptimality (fuel efficiency) improvement, potential real-time applicability, and constraints (especially charge balance constraint) satisfaction in the presence of driving cycle uncertainty.
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Title: Thermal Effects in Fluid Dynamics
Creator: Sulzbach, Jan-Eric
Date: 2021
Description: In this thesis we propose a mathematical framework modeling non-isothermal fluids.The framework is based on a coupling between non-equilibrium...
Show moreIn this thesis we propose a mathematical framework modeling non-isothermal fluids.The framework is based on a coupling between non-equilibrium thermodynamics and an energetic variational approach for the mechanical parts of the system. From this general model we derive and analyze three separate systems.The first application is the Brinkman-Fourier model. This is related to the ideal gas system, where the pressure and internal energy depend linearly on the product of density and temperature. This is a subsystem to the general Navier-Stokes-Fourier system. We prove the existence of local-in-time weak solutions via compensated compactness arguments.The next model we study is a non-isothermal diffusion system involving chemical reactions. For a system close to chemical equilibrium we show the well-posedness of classical solution using a fixed-point argument involving theory of homogeneous Besov spaces.The third application of the general theory is for another general diffusion system with a Cahn-Hilliard energy. In this framework, we study in detail how the temperature can affect the system on different scales, leading to different models. For the analysis, we focus on one case and show the well-posedness of classical solutions. The proof relies on methods from the theory of Besov spaces and paradifferential calculus.
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Title: Technological Consciousness in Midwestern American Farming: From Party Lines to Autonomous Tractors
Creator: Sziron, Mónika
Date: 2022
Description: This dissertation is primarily concerned with understanding the current conceptions, perceptions, and ethical concerns of artificial...
Show moreThis dissertation is primarily concerned with understanding the current conceptions, perceptions, and ethical concerns of artificial intelligence in Midwestern agriculture. Using the theory of technological consciousness as a backdrop for understanding the relationship between Midwestern agriculture and technology, in chapter two this dissertation first provides a narrative review of major technological developments throughout history in Midwestern farming and how the human experience in farming is influenced by technology throughout history. This history provides context for the current state of Midwestern agriculture, which is now increasingly entangled with artificial intelligence. The theory behind artificial intelligence ethics and general trends in artificial intelligence are discussed in chapter three. To understand present conceptions, perceptions, and ethical concerns of artificial intelligence for Midwestern farmers, a pilot survey was dispersed to farmers and pilot media content analysis was conducted on Midwestern agriculture publications. The results from this pilot survey and pilot media content analysis are discussed in chapter four. Chapter five delves into theory and how the human experience with technology has evolved over time and its effects on the human experience today. This chapter also provides theoretical insights for the future of farming with artificial intelligence. The dissertation concludes with reviewing the ethical concerns relating to artificial intelligence in agriculture for Midwestern farmers, provides recommendations for developers of agriculture technology, and highlights the new partnership between farmers and computer scientists and how this partnership will lead the way in the future of Midwestern farming.
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Title: Biophysical and Computational Characterization of CinDel Edits of Dystrophin
Creator: Stojkovic, Vladimir
Date: 2022
Description: Duchenne muscular dystrophy (DMD) is a degenerative genetic disease caused by a genetic defect that results in the absence of dystrophin, a...
Show moreDuchenne muscular dystrophy (DMD) is a degenerative genetic disease caused by a genetic defect that results in the absence of dystrophin, a protein with an important stabilizing role in muscle cells. DMD causes progressive muscle degeneration leading to the loss of ambulation, and typically results in death before the third decade of life. Treatments for DMD aim to restore dystrophin expression and typically do so by producing edited or modified dystrophins. The only FDA approved therapy, exon skipping, produces dystrophin edits at exon boundaries but emerging therapeutic approaches like gene replacement therapy and CRISPR-Cas9-based gene editing techniques like CinDel allow for greater flexibility and are not constrained to exon boundary edits. However, understanding of what makes a “good”, functional edit is limited so it is not clear how to make use of this increased flexibility to produce optimal edits which are believed to be necessary for robust treatment. In an effort to improve understanding of the biophysics of these non-exon edits, we have embarked on a mixed experimental and computational study of a set of CinDel edits in the D19-D21 region of the dystrophin central rod domain. First, we have conducted an Alphafold structure prediction-based screen of a subset of possible edits in this region and selected one edit for follow-up characterization. We then compared this computationally-selected edit to three other heuristically designed edits experimentally and computationally by molecular dynamics simulations. We found that the computationally selected edit is significantly more thermodynamically stable than the other edits in the cohort. This edit also generally exhibited more favorable properties in MD simulations across multiple measures such as helicity, STR-junction unwinding and conformational variability.
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Title: Health Information Seeking, Depression, and Satisfaction with Life in Racial/ethnic Minority vs. White individuals with Spinal Cord Injuries
Creator: Stipp, Kelsey
Date: 2022
Description: Health information is available both traditionally by conversations with health care professionals, and non-traditionally via use of the...
Show moreHealth information is available both traditionally by conversations with health care professionals, and non-traditionally via use of the Internet and other media sources. Health information is crucial to individuals with chronic health conditions and/or disabilities, such as spinal cord injury (SCI), to promote health, minimize comorbidities, and improve quality of life (QOL). Methods of health information seeking have been shown to differ between individuals who are racial/ethnic minority individuals and individuals who are White. Existing research appears to show health information seeking may increase QOL in populations with chronic health conditions and/or disabilities. However, it is unclear how aspects of QOL differ between individuals within the SCI population by race/ethnicity. The present study used Chi Square analyses to test racial/ethnic group differences in health information seeking and multiple analysis of covariance (MANCOVA) to test whether method of health information seeking and aspects of QOL, specifically depression and satisfaction with life, were moderated by race/ethnicity. An adult sample of 9,403 individuals with SCI who completed a survey on their injury, health, and QOL between 2011 and 2016 was used. Participants identified their source of health information as traditional (i.e., conversations with health care professionals) or non-traditional (e.g., newspaper, television, radio, etc.). Results indicated non-traditional sources of health information were utilized more frequently regardless of race/ethnicity. Unexpectedly, moderation results suggested that associations between source of health information and depression and satisfaction with life did not differ by race/ethnicity. However, source of health information was associated with satisfaction with life and depression for the entire sample. Study findings demonstrate the shift towards non-traditional (e.g., newspaper, television, radio, etc.) health information seeking within the SCI population. Further, findings support previous empirical work demonstrating the association between method of health information seeking and depression and satisfaction with life. These findings can be used to improve dissemination of accurate health information to the SCI population via non-traditional sources. Further research should include more diverse samples of individuals to better understand health information seeking as well as depression and satisfaction with life within the SCI population.
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Title: A Functionalized 2D Boron Nitride Electrode for Rechargeable Batteries
Creator: Tatagari, Vignyatha Reddy
Date: 2021
Description: Motivated by the great performance of the graphene oxide battery and its poor safety, in the present work, an attempt is made to fabricate an...
Show moreMotivated by the great performance of the graphene oxide battery and its poor safety, in the present work, an attempt is made to fabricate an alternative battery from functionalized 2-dimensional (2D) boron nitride. The expectation is that functionalized boron nitride can exhibit the same great electrochemical performance as graphene oxide while it would be much more thermally stable. Toward this goal, synthetic opportunities were explored to realize -OBF3 functionalized hexagonal boron nitride. Both top-down and bottom-up synthetic approaches were considered and implemented. In the top-down methods, commercially available bulk hexagonal boron nitride (h-BN) is reacted with functionalization agents such as LiOBF3 and LiOH.BF3. Synthesis of these functionalization agents and their reactions with h-BN were carried out in several different ways. Bottom-up synthetic approach using Boric Acid and Urea was utilized to synthesize turbostratic boron nitride (t-BN), which is an intermedier in the commercial synthesis of hexagonal boron nitride. Turbostratic boron nitride contains exfoliated and -OH functionalized monolayers of boron nitride. An attempt is made to esterify the -OH groups of turbostratic boron nitride to obtain the desired -OBF3 functionalized monolayers of h-BN. Initial electrochemical tests on turbostratic boron nitride and its esterified form are carried out along with ionic conductivity measurements. Only a very limited electrochemical activity was observed due to a low degree of functionalization in these materials, indicating the need for improved synthetic procedures to achieve the desired target materials.
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Title: PIMMINER: A HIGH-PERFORMANCE PIM ARCHITECTURE-AWARE GRAPH MINING FRAMEWORK
Creator: Su, Jiya
Date: 2022
Description: Graph mining applications, such as subgraph pattern matching and mining, are widely used in real-world domains such as bioinformatics, social...
Show moreGraph mining applications, such as subgraph pattern matching and mining, are widely used in real-world domains such as bioinformatics, social network analysis, and computer vision. Such applications are considered as a new class of data-intensive applications that generate massive irregular computation workloads and memory accesses, which degrade the performance and scalability significantly. Leveraging emerging hardware, such as process-in-memory (PIM) technology, could potentially accelerate such applications. In this paper, we propose PIMMiner, a high-performance PIM architecture graph mining framework. We first identify that current PIM architecture cannot be fully utilized by graph mining applications. Next, we propose a set of optimizations that enhance the locality, and internal bandwidth utilization and reduce remote bank accesses and load imbalance through cohesive algorithm and architecture co-designs. We compare PIMMiner with several state-of-the-art graph mining frameworks and show that PIMMiner is able to outperform all of them significantly.
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Title: DO ACT CONSTRUCTS MODERATE ASSOCIATIONS BETWEEN SOCIAL MEDIA AND EATING PATHOLOGY?
Creator: Badillo Regan , Krystal E
Date: 2022
Description: Limited research has assessed individuals with disordered eating and their social media use. Additionally, there has been limited...
Show moreLimited research has assessed individuals with disordered eating and their social media use. Additionally, there has been limited investigation into psychotherapy constructs that could be used when addressing social media use in those with eating pathology. This study aims to improve the existing literature on social media and eating pathology by recruiting a sample of probable eating disorders and assessing if Acceptance and Commitment Therapy (ACT) constructs moderate the relation between social media and eating pathology. It is anticipated that 1) eating disorder pathology severity will be positively correlated with photo-based social media behavior; 2) eating disorder symptom severity will be positively associated with importance of social media; and 3) those who score higher in mindful eating, body image flexibility, and body image acceptance will have a weaker positive association between ED pathology and importance of social media and those who score lower in body image cognitive fusion will have a weaker positive association between ED pathology and importance of social media mindful eating, body image flexibility, body image acceptance, and body image cognitive fusion will moderate the relation between eating disorder symptom severity and social media use. To test the hypotheses women with a probable eating disorder (N=121) completed online questionnaires via prolific. The majority of participants identified as non-Hispanic (81%) and White (45.5%). Results suggest that there are associations between ED pathology, ACT constructs, Importance of Twitter and Instagram, and photo-based behaviors but not Importance of Facebook. Additionally, the moderation models examined were not statistically significant. Implications of these findings are discussed as well as future direction for research and clinical work.
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Title: OPTIMUM WEIGHT STIFFNESS STRUCTURAL DESIGN
Creator: Barnett, Ralph L.
Date: 2021
Description: My adventures with flexible structures began on the IIT campus with an extracurricular undergraduate project to design an “Open House Exhibit”...
Show moreMy adventures with flexible structures began on the IIT campus with an extracurricular undergraduate project to design an “Open House Exhibit” for the Civil Engineering Department. I chose to display a reinforced concrete diving board together with a prestressed concrete diving board. Visitors enthusiastically pounced on the reinforced concrete structure whose rigid response disappointed one and all. Their indignation was transferred to the prestressed cantilever which thrust them upward from six to ten feet into the air. This unexpected response from a diving board became so dangerous that the Exhibit was unceremoniously closed. I still have the display sign, “More Bounce to the Ounce.”While still an undergraduate, I secured a part-time job at Armour Research Foundation where I responded to a bid request from Rock Island Arsenal to design the 26 foot Honest John Rocket Launcher Rail at minimum weight. This tactical weapon was transported by helicopter. I basked in the fantasy that I was Leonardo da Vinci without his artistic proclivity. Rocket launchers that droop during operation are similar in concept to a circular firing squad. So began my research into minimum weight beams based on deflection rather than strength. I searched for the shoulders of Giants. I found them in the form of mathematicians not structural engineers. I achieved a 26.5% weight savings in the 1126 pound rail by optimizing the geometry. When I developed an optimum prestressed and segmented Kentanium cermet rail, the weight savings became 89%. The right material provides a bigger bang for the buck. When my journey into optimum design began, I was armed only with analysis tools: strength, stability, and stiffness. This thesis begins with an outline of my present toolbox which contains eight design concepts: 1. Establish the Geometry, 2. Select a material from a finite number of candidates, 3. Prestress and Prestrain, 4. Statistical Screening (Proof Testing), 5. Manipulation of Boundary Conditions, 6. Energized Systems, 7. Counterweights, 8. Self-Healing and Self-Reinforcing. Four of these are used through this review which focuses on stiffness. Beginning with beams, deflection control examples are described where prestraining and prestressing techniques are used to produce both a zero-deflection beam and a method for pushing with a chain. The calculus of variations made it possible to establish optimum tapers for the flanges and webs of I-beams that minimize beam weight for a specified deflection or, because of reciprocity, minimize beam deflection for a specified beam weight. An anomaly is encountered that enables one to achieve an upward, downward, or zero deflection with a set of beams of vanishing weight. In addition, special circumstances are defined where a uniform strength design is identical to the minimum weight design based on a specific deflection. Closed form solutions are obtained for a variety of loading scenarios. One problem is presented for self-weight that leads to a nonlinear integral equation. The optimum stiffness-weight design of trusses is undertaken where the area distribution of the truss members is optimized using Lagrange’s method of undetermined multipliers. Once again, we obtain a degenerate case where upward, downward, and zero deflection conditions can be met with an infinite set of trusses of vanishing weight. We photograph a simply supported truss under a downward load that leads to an upward deflection at one of the joints. Special loading conditions are identified that lead to uniform stress designs that are identical to the minimum weight designs based on deflections. This study provides a Segway into the world of minimum weight strength design of trusses. The resulting Maxwell and Michell trusses sometimes display the optimum distribution of bar areas from the point of view of stiffness. Many practitioners are under the mistaken impression that Michell structures, when they exist, provide the optimum truss profile for stiffness. Unfortunately, the optimum array of truss joints based on deflection does not exist. For both trusses and beams the optimum distribution of mass is shown to be necessary and sufficient; the sufficiency is established using well-known inequalities. The role of stiffness in the design of columns is explored in our final chapter. This cringe-worthy history of column analysis begins our study as a warning to practitioners who use analysis as their basis for design and especially optimum design. Conventional elastic and inelastic buckling theories provide little insight into the design of columns. The fundamentals of minimum weight column design are presented to show the power of design theory in contrast to analysis. Both prismatic and tapered columns are studied with one surprise result; the optimum taper gives rise to a uniform bending stress (without axial stresses). It was fun to see that in 1733 Lagrange made a mistake in calculus of variations that led to the incorrect solution for the optimum tapered column. It took 78 years before Clausen obtained the correct solution. The problem has been revisited by William Prager and again by the author who used dynamic programming. Of course, we all got the same result which is a dreadful solid circular tapered column that is heavier than any ordinary waterpipe. The best of a class is not necessarily the best possible design. Under the heading, “Intuition is a good servant but a bad master,” we introduce the notions of tension members that buckle, columns constructed from spherical beads, optimum rigging of crane booms, and deflection reversal of beam-columns. In several places we observe that the weight of optimum columns is proportional to P^α where P is the axial load and α is less than unity. We fail to tell the reader that this implies that minimum weight columns require putting all your eggs in one basket; one column under load P is lighter than two columns each under load P/2. On the other hand, we expose the solid circular column as the least efficient shape among all regular polygons, the equilateral triangle is the best. Indeed, there is a family of rectangles that are superior to the circular cross-section. Finally, the author’s prestressed tubular column is introduced that is pressurized to eliminate local buckling. Euler’s buckling can always be eliminated with a thin-wall section of sufficient width without a weight penalty. The weight of the balloon-like member is proportional to (PL) which implies that at last we have a compressive member that meets the requirement of a Michell structure. Bundling of pressurized gas columns are possible without a weight penalty. Further, the column is insensitive to most imperfections. It is the lightest known column for small structural indices (P/L^2 ). When coupled with circulating cryogenic liquid as a prestressing system, a limiting column has a vanishing weight.
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Title: A Network Analysis of the Six Core Processes Associated with Acceptance and Commitment Therapy
Creator: Bailey, Jennifer Rose
Date: 2022
Description: According to the theoretical model of Acceptance and Commitment Therapy, six core processes comprise a latent factor of psychological...
Show moreAccording to the theoretical model of Acceptance and Commitment Therapy, six core processes comprise a latent factor of psychological flexibility: present moment, chosen values, committed action, self as context, cognitive defusion, and acceptance. Little research has directly examined the unique relations among the processes. The present study extended our knowledge of the structure and relations between these processes by examining the relative importance and influence of a single process to the system of processes as a whole utilizing network analysis with a sample of 277 adult, non-clinical participants. Committed action was the most central of all the processes, demonstrating the highest strength centrality and most number of edges. Cognitive defusion and present moment also showed high strength centrality, suggesting that these processes exert the greatest influence on other processes in the network based on partial correlations controlling for all other constructs. Results provided support for the conceptualization of the three response styles (i.e., open, centered, and engaged). The addition of neuroticism to the core processes network showed little effect on the number of edges present between the six core processes. Neuroticism was strongly related to cognitive defusion and more weakly related to committed action. Results not only increased our understanding of the relations between processes and provided knowledge that may be useful to our understanding of the ACT theoretical model, but it also may have potential clinical implications, such as aiding in the identification of treatment targets to enhance psychological flexibility.
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Title: DESIGN FOR COMFORT: DESIGN BUILDING ENVELOPE TO IMPROVE THERMAL COMFORT FOR RESIDENTIAL BUILDINGS IN AL-MUKALA, YEMEN
Creator: Bakarmom, Aamena Mubarak Saeed
Date: 2021
Description: This thesis is about the research into the design of building envelopes to reduce energy consumption and moderate thermal performance of the...
Show moreThis thesis is about the research into the design of building envelopes to reduce energy consumption and moderate thermal performance of the residential buildings in Yemen, which is in an arid climate. A suitable building envelope is important because of the building occupants’ thermal comfort. The most important question is how architects could implement high-performance envelope technologies in their designs, especially in residential buildings. These technologies have some basic principles which are applied differently from one region to another. One of the most promising strategies applied to house envelopes in a hot-dry climate is the passive cooling design. This thesis reviews the results of other research in the same region that discuss proper parameters of building envelopes such as form, width, climate, walls, materials, and windows design. Passive cooling strategies will be the key to providing potential design building envelopes that provide thermal comfort and reduce energy use. This study applies the natural ventilation principle (single-sided, cross- or stack ventilation), thermal mass, and shaded devices. The research methods were to collect data and create quantitative models to analyze the data. From this analysis, I suggest specific architecture guidelines for design in residential buildings which could improve comfort in indoor spaces for occupants.
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Title: SEPARATING NOBLE GASES SUCH AS KRYPTON AND XENON FROM NUCLEAR POWER PLANTS OFF-GAS USING DD3R ZEOLITIC MEMBRANES: A COMPUTATIONAL MOLECULAR DYNAMICS STUDY
Creator: BASHMMAKH, BANDAR JAMAL S.
Date: 2021
Description: Noble gas fission products generated within nuclear power reactors, such as Kr and Xe, are currently discharged into the atmosphere. This...
Show moreNoble gas fission products generated within nuclear power reactors, such as Kr and Xe, are currently discharged into the atmosphere. This practice has a major economic drawback because of the high value associated with some of these gases. Zeolites, nanoporous materials suitable for gas separation processes, have become of major interest due to the potentially high selectivity for such separations. We have used nonequilibrium molecular dynamics to investigate the separation performance of DD3R framework zeolitic membranes (using LAMMPS software package) for such separations. Our studies have shown that the DD3R membrane shows promise for high selectivity ratios of Kr over Xe. The effects of pressure, temperature and pure vs. mixture gas feed conditions are studied in this work to understand at the molecular level the mechanisms of these (Kr/Xe) separations. MD runs show an agreement with most experimental trends in the permeation of Kr/Xe pure and mixed gases using DD3R zeolite with high separation factor, despite the absence of Xe complete permeation through the membrane because of MD timescale limitation, signaling much slower diffusion in comparison to Kr which is a desired trend in looking for high separation factors.
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Title: INFORMAL AREAS UPGRADING STRATEGIES: THE CASE OF ADEN CITY-YEMEN
Creator: Ba Tis, Ahmed Abdullah Obaid
Date: 2022
Description: Informal areas are global problems that pose a threat to the urban environment and their consequences prompted urgently to search for...
Show moreInformal areas are global problems that pose a threat to the urban environment and their consequences prompted urgently to search for solutions and methods to address these problems and limit their effects. This thesis examines the issue of informal areas in Yemen. Informal areas are houses built on illegal public or private real estate. In Yemen, these illegal areas began as a relatively new phenomenon and since then have grown at an extremely rapid rate. Increasing rates of urbanization, poverty, and unemployment have led to the rapid rise of slums and informal housing in Yemen. The UN-Habitat database of global urban indicators estimates that 60% of Yemen's urban population lives in informal settlements. The cities most affected by the rapid growth of informal settlements include Taiz, Al Hudaydah, Sana'a, and Aden. The Yemeni government has done little to address the growth of informal areas. However, there was growing concern about this issue, and governmental and non-state actors alike began to consider new approaches to urban policy development and implementation. The importance of the thesis is that it will limit the spread of slums in Aden in the future, and it will also be a good starting point for further research and studies on the issue of developing the problem of informal areas in Yemen. There are many ways to deal with the problem of informal areas, including demolition and resettlement, and development upgrading and each method differs according to the region’s conditions, whether the urban, social economic, location of the area. This study focuses on urban upgrading to clarify its concepts, types and strategies, because it has become one of the most appropriate ways to deal with informal areas and to reach a sustainable urban environment. The thesis aims to find solutions for informal areas in Yemen and limit their growth in the future by preparing a new strategy for dealing with informal areas, in light of the experiences of other countries, and in line with the reality of Yemen.
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Title: Sharpen Quality Investing: A PLS-based Approach
Creator: Jiao, Zixuan
Date: 2022
Description: I apply a disciplined dimension reduction technique called Partial Least Square (PLS) to construct a new quality factor by aggregating...
Show moreI apply a disciplined dimension reduction technique called Partial Least Square (PLS) to construct a new quality factor by aggregating information from 16 individual signals. It earns significant risk-adjusted returns and outperforms quality factors constructed by alternative techniques, namely, PCA, Fama-Macbeth regression, a combination of PCA and Fama-Mabeth regression and a Rank-based approach. I show that my quality factor performs even better during rough economic patches and thus appears to hedge periods of market distress. I further show adding our quality factor to an opportunity set consisting of the other classical factors increases the maximum Sharpe ratio.
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Title: MICROSTRUCTURE AND MECHANICAL PROPERTIES OF DISCONTINUOUSLY PRECIPITATED NI-CO-AL ALLOYS
Creator: Ho, Kathy
Date: 2022
Description: The study of high temperature structural materials has been one of great interest and immense focus in recent years of research and...
Show moreThe study of high temperature structural materials has been one of great interest and immense focus in recent years of research and development. With the capability of catering to specific needs and applications while being commercially cost-effective, these materials can be synthesized using various types of methods and materials for a large range of applications. In order to implement the advantageous properties of these materials for practical use in service, empirical data relating to the material and mechanical properties of these high temperature structural alloys must first be obtained. This can be achieved through numerous processing methods. One particular method involves precipitation strengthening. Two types of transformation modes include discontinuous and continuous precipitation. Discontinuous precipitation (DP) nucleates at high angle, incoherent grain boundary, grows through grain boundary diffusion, and produces a lamellar structure consisting of alternating layers of γ and γˡ (Ephler, 2004). Continuous precipitation (CP) nucleates within the grain, is controlled through volume diffusion producing, and results in a homogeneous distribution of equilibrium composition precipitates with a spherical/cuboidal morphology. Since both modes of transformation possess a chemical driving force, resulting from the supersaturation of solute, the coexistence of both DP and CP transformation in a material is possible. However, as demonstrated from past studies, the presence of a partial DP transformation in structural alloys is undesirable as detrimental effects on mechanical properties are observed. As a result, numerous studies have focused on suppressing DP all together. In 1972 Erhard Hornbogen hypothesized that a fully DP transformed material would yield superior mechanical properties, similar to pearlite formation in steel, since the lamellar structure would increase barriers to dislocation movement (Hornbogen, 1972). As a result, recent studies have redirected their focus in an effort to encourage DP transformation to completion for improved mechanical properties. Therefore, the purpose of this work was to 1) determine the aging conditions under which a complete, 100% DP transformation would be achieved in select alloys, 2) determine the conditions where optimal precipitate size via CP transformation is obtained to effectively use precipitation strengthening without the concern of over-aging, 3) experimentally compare the material and mechanical properties between 100% DP aged samples and CP aged samples consisting of the optimal precipitate size, 4) compare the mechanical properties between alloys that have undergone a complete DP transformation to commercial alloys currently used in service, and 5) provide empirical data to verify Hornbogen’s claim. The results from this work indicated that 1) a lower aging temperature promote DP transformation while a higher temperature promotes CP transformation, 2) a smaller grain size prior to aging was more favorable for DP transformation while larger grains were favorable for CP transformation, 3) a complete DP transformation was observed for Alloy 9 and Alloy 10 after aging at 500°C for 4 hours and 550°C for 4 hours, 4) Alloy 1, Alloy 3, and Alloy 5 were potentially undergoing a different type of transformation at lower DP aging temperatures, where β phase was present, 5) optimal precipitate size for effective use of precipitation strengthening (CP transformation) was achieved under CP aging conditions 700°C-1HR for Alloy 10 and 750°C-1HR for Alloy 9 and the forged stock bar, 6) a small fraction of DP consistently formed at the grain boundaries of the CP aged samples for all alloy samples, indicating that the nucleation of DP was quick, but growth was limited, 7) mechanical properties of the DP aged samples for Alloy 9, Alloy 10 and the forged bar were superior to their corresponding CP aged samples in terms of the hardness, UTS, and yield stress, but were less ductile than the CP aged samples, and 8) the mechanical properties of DP aged samples for Alloy 9, Alloy 10, and the forged bar were comparable, and at times superior, to the commercially available alloys. Due to limited prior research conducted on the mechanical properties of DP alloys, this investigation serves as a pioneering effort experimentally determine if the mechanical properties of completely DP transformed material are superior to that of CP transformed material, aged to optimal precipitate size, while collecting empirical data to verify Hornbogen’s claim.
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Title: EMAT DESIGN CONFIGURATIONS AND SOFTWARE-DEFINED ULTRASONIC COMMUNICATIONS THROUGH METALLIC CHANNELS IN NUCLEAR FACILITIES
Creator: Huang, Xin
Date: 2022
Description: Nuclear facilities are partitioned into different blocks, and all equipment therein is well-packed for isolation purposes. The primary...
Show moreNuclear facilities are partitioned into different blocks, and all equipment therein is well-packed for isolation purposes. The primary barriers of each block include a thick, reinforced, high-strength concrete wall. The presence of physical boundaries introduces a major challenge to implementing wired or radio frequency (RF) wireless communication. Achieving data communication through the solids channel, especially considering the complex environment in nuclear power plants, is very challenging. Ultrasonic communication is a desirable method for information transfer through solid mediums such as metallic bars or pipes. This thesis is methodologically innovative in the way it seeks the best solution for ultrasonic communications through metallic channels. Therefore, we address the following research areas: 1. The advantages of using electrical-magnetic acoustic transducers (EMATs) as transmitter and receiver; 2. The fundamentals of the EMAT structure and wave generation mechanism for ultrasonic communications; 3. The channel model and behavior of ultrasonic wave propagation in a different structure of solid channels; 4. How to minimize the adverse impact of wave dispersion and reverberation; 5. How to increase the bitrate and decrease the bit error rate (BER) of an ultrasonic communication system; 6. How to utilize the software-defined system-on-chip (SoC) platform for ultrasonic communications; and 7. How to implement secure ultrasonic video transmission through solid channels. In this thesis, we have investigated the feasibility of using Periodic-permanent-magnet electromagnetic acoustic transducers (PPM-EMATs) transmitter and receiver as the information-bearing of ultrasonic waves across the plate channels (shear horizontal waves) and pipe channels (torsional waves). Methods such as time-reversal (TR), pulse shaping, and adaptive equalizer techniques are studied for improving the signal-to-noise ratio (SNR) of ultrasonic communication systems. We also investigated a novel software-defined ultrasonic communication system (SDUC) for real-time video transmission through a highly reverberant and dispersive metallic bar channel. Furthermore, we investigated the feasibility of combining orthogonal frequency-division multiplexing (OFDM) with quadrature amplitude modulations (QAM) for bitrate peak performance. Strategies and guidelines were established for the best solutions to combat intersymbol interference (ISI) caused by the severe reverberation inherent in metallic channels. A practical solution for video transmission, adhering to the Digital Video Broadcasting Terrestrial (DVB-T) standard, was also examined for video streaming transmission of 240p, 480p, and 720p resolutions at 20 frames per second (FPS) across a rectangular aluminum bar (ARB) channel. Through ultrasonic experimental studies for channel analysis, we achieved a peak video transmission rate of 1074 kbps with 3.3×10-4 BER despite reverberation, the multipath effect, and signal fading within the ARB channel.
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Title: Numerical Analysis and Deep Learning Solver of the Non-local Fokker-Planck Equations
Creator: Jiang, Senbao
Date: 2022
Description: This thesis is divided into three mutually connected parts. ...
Show moreThis thesis is divided into three mutually connected parts. In the first part, we introduce and analyze arbitrarily high-order quadrature rules for evaluating the two-dimensional singular integrals of the forms \begin{align*} I_{i,j} = \int_{\mathbb{R}^2}\phi(x)\frac{x_ix_j}{|x|^{2+\alpha}} \d x, \quad 0< \alpha < 2 \end{align*} where $i,j\in\{1,2\}$ and $\phi\in C_c^N$ for $N\geq 2$. This type of singular integrals and its quadrature rule appear in the numerical discretization of fractional Laplacian in non-local Fokker-Planck Equations in 2D. The quadrature rules are trapezoidal rules equipped with correction weights for points around singularity. We prove the order of convergence is $2p+4-\alpha$, where $p\in\mathbb{N}_{0}$ is associated with total number of correction weights. We present numerical experiments to validate the order of convergence of the proposed modified quadrature rules. In the second part, we propose and analyze a general arbitrarily high-order modified trapezoidal rule for a class of weakly singular integrals of the forms $I = \int_{\R^n}\phi(x)s(x)\d x$ in $n$ dimensions, where $\phi$ and $s$ is the regular and singular part respectively. The admissible class requires $s$ satisfies three hypotheses and is large enough to contain singular kernel of the form $P(x)/|x|^r,\ r > 0$ where $P(x)$ is any monomial with degree strictly less than $r$. The modified trapezoidal rule is the singularity-punctured trapezoidal rule plus correction terms involving the correction weights for grid points around singularity. Correction weights are determined by enforcing the quadrature rule to exactly evaluate some monomials and solving corresponding linear systems. A long-standing difficulty of these types of methods is establishing the non-singularity of the linear system, despite strong numerical evidence. By using an algebraic-combinatorial argument, we show the non-singularity always holds and prove the general order of convergence of the modified quadrature rule. We present numerical experiments to validate the order of convergence. In the final part, we propose \emph{trapz-PiNN}, a physics-informed neural network incorporated with a modified trapezoidal rule and solve the space-fractional Fokker-Planck equations in 2D and 3D. We verify the modified trapezoidal rule has the second-order accuracy for evaluating the fractional laplacian. We demonstrate trapz-PiNNs have high expressive power through predicting solutions with low $\mathcal{L}^2$ relative error on a variety of numerical examples. We also use local metrics such as point-wise absolute and relative errors to analyze where could be further improved. We present an effective method for improving performance of trapz-PiNN on local metrics, provided that physical observations of high-fidelity simulation of the true solution are available. Besides the usual advantages of the deep learning solvers such as adaptivity and mesh-independence, the trapz-PiNN is able to solve PDEs with fractional laplacian with arbitrary $\alpha\in (0,2)$ and specializes on rectangular domains. It also has potential to be generalized into higher dimensions.
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Title: CHARACTERIZATION OF HERBS AND SPICES PHYTOCHEMICALS AND PHARMACOKINETIC PROFILE OVER 24-HOUR AFTER CONSUMPTION IN OVERWEIGHT/OBESE ADULTS
Creator: Huang, Yudai
Date: 2022
Description: The health benefits of herbs and spices (H/S) have been known since ancient times. They are a rich source of phytochemicals, such as phenolic...
Show moreThe health benefits of herbs and spices (H/S) have been known since ancient times. They are a rich source of phytochemicals, such as phenolic compounds and terpenoids. However, there is limited information on their absorption and metabolism in humans. Therefore, the primary objective of this study is to identify and characterize phytochemical compounds in H/S mixtures and their absorption and metabolism in the human body over 24 h. H/S and plasma samples used in this study were from a randomized, single-blinded, 4-arm, 24 h, multi-sampling, single-center crossover clinical trial (Clincaltrials.gov NCT03926442) conducted in obese or overweight adults (n=24, aged 37 ± 3 years, BMI=28.4 ± 0.6 kg/m2). Plasma samples were collected at baseline (t=0 h), 0.5, 1, 2, 4, 5.5, 7, and 24 h after consuming a high-fat high-carbohydrate (HFHC) meal with salt and pepper (control) or the control meal with 6 g of three different H/S mixtures (Italian herb: rosemary, basil, thyme, oregano, and parsley in the same ratio; cinnamon; and pumpkin pie spice containing cinnamon, ginger, nutmeg and allspice, the ratio unknown). The phytochemical compounds in the H/S mixtures and their metabolites in human plasma were tentatively identified and quantified by dynamic multiple reaction monitoring transitions on UHPLC-QQQ-MS/MS. Statistical analysis was conducted on SAS-PC 9.4 using non-parametric test via NPAR1WAY procedure. A total of 79 phytochemical compounds were quantified from samples of three H/S mixtures and pepper, of which 36 were flavonoids conpounds, 8 were terpenoids, 27 phenolic acids, and 9 were identified as other compounds. Acetone showed the highest extraction ability for both (poly)phenols and terpenoids in H/S compared to other organic solvents (50% and 80% methanol, ethyl acetate and chloroform). Italian herb contains 763.1 mg/100 g flavonoids, 879 mg/100 g phenolic acids, and 498.6 mg/100g terpenoids; cinnamon contains 981 mg/100 g flavonoids, 11.2 mg/100g phenolic acids, 292.3 mg/100g coumarin, and 1977.1 mg/100 g cinnamaldehyde; pumpkin pie spice contains 655.8 mg/100 g flavonoids, 17.1 mg/100 g phenolic acids, 226.5 mg/100 g coumarin, and 1633 mg/100 g cinnamaldehyde. A total of 47 metabolites were tentatively identified and quantified in plasma samples after H/S consumption over 24 h. Plasma concentrations of carnosic acid derivatives and the glucuronidation products increased after intake of Italian herb, and the Area under the curve (AUC0-24h) was significantly different from control (all P < 0.05) except carnosol glucuronide. Carnosic acid and carnosol had Tmax at 3.4±1.1 and 1.8±0.3 h, respectively, while both of their conjugated glucuronides kept increasing until 24 h. Coumarin glucuronide was increased by cinnamon and pumpkin pie spice consumption with peak concentrations reached at between 1.5-1.6 h. The AUC0-24h after both meals were significantly different from control meal, both P < 0.05. Our results suggest that H/S contain diverse categories of phytochemical compounds that are absorbed and metabolized in the human body into various metabolites in response to 3 different H/S test meals and their appearance in the blood starts as early as around 0.5 h and extends to as long as 24 h for select metabolites.
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Title: FACTORS INFLUENCING INDIVIDUALS’ PROVISION OF AUTONOMY SUPPORT TO THEIR PARTNERS WITH CHRONIC PAIN: A PATH ANALYSIS MODEL BASED ON SELF-DETERMINATION THEORY
Creator: Ivins-Lukse, Melissa N.
Date: 2021
Description: Receiving autonomy support from a relationship partner has been associated with increased physical activity among individuals with chronic...
Show moreReceiving autonomy support from a relationship partner has been associated with increased physical activity among individuals with chronic pain (ICP), but no studies have explored what factors may influence partners’ use of an autonomy supportive interpersonal style with an ICP. Self-determination theory (SDT) posits that contextual, perceptual, and individual factors influence how much individuals use an autonomy supportive interpersonal style through the mediators of basic psychological need satisfaction and autonomous motivation. The present study used path analysis to test a SDT model of the relationships between a contextual factor (autonomy support from health care provider), a perceptual factor (partner’s perception of ICP motivation for physical activity), an individual factor (partner catastrophizing about ICP’s pain), and the sequential mediators of relationship need satisfaction and autonomous motivation with respect to the dependent variable of partners’ use of an autonomy supportive interpersonal style. 176 partners of ICPs completed a cross-sectional survey including the Health Care Climate Questionnaire, partner-report revised Behavioral Regulation in Exercise Questionnaire, Pain Catastrophizing Scale – Significant Other version, Need Satisfaction Scale, Motivation to Help, and Interpersonal Behaviours Questionnaire-Self. The proposed model demonstrated poor fit to the data: χ2 (10) = 31.949, p < 0.001), RMSEA = 0.11 (90% CI = .07 to .16, p = 0.01), CFI = 0.81, and SRMR = .10. While the overall model was not supported, most individual pathways in the model were significant. Alternative analyses were conducted to identify a model with acceptable fit.
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Title: Advances in Distribution System State Estimation
Creator: Huang, Jianqiao
Date: 2022
Description: With the increasing penetration of renewable energy in the distribution system, the system states are becoming more volatile. How to maintain...
Show moreWith the increasing penetration of renewable energy in the distribution system, the system states are becoming more volatile. How to maintain the normal operation is an urgent question to the operators. Distribution system state estimation (DSSE) is the key to the monitor and control of distribution systems.Distribution systems feature a larger number of nodes and heterogeneous measurements. Due to these features, directly employing traditional state estimation methods cannot provide fast and accurate estimation results. The existing semidefinite programming based methods show promising for the accuracy, but it is not scalable for a large system. In this thesis, we propose fast and accurate DSSE methods. First, we improve the efficiency of the state-of-art SDP-DSSE method, convex iteration (CI) method. We design a scalable convex iteration method, CDQC, by fully exploiting the radial topology of distribution system. However, the efficiency of CDQC depends on efficient feeder partition solution. It is time-consuming to get a good partition especially when the system is large. Hence, we propose a bus injection based semidefinite relaxation method (SDR-BIM) that fully exploits the radial topology of the network without the need for partitioning the networks. However, SDR-BIM has numerical issue for large scale network. This motivates us to design a branch power model based SDR-DSSE method. The proposed SDR-BPM-DSSE method improves the numerical stability and the increase in the average estimation error of voltage is less than $0.04\%$. To further improve the computational efficiency, we developed a generalized linear power flow model (GLDF) and propose an iterative method to solve the DSSE based on GLDF.Finally, the efficiency and accuracy of the proposed methods are validated on IEEE 13-bus, 37-bus, 123-bus, and 8500-node test feeders.
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