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Title: AN INVESTIGATION INTO THE SIGNIFICANCE OF LENGTH-THICKNESS RATIO IN GUSSET PLATE BEHAVIOR IN BRIDGE TRUSSES
Creator: Olechno, Patrick
Date: 2012-07-12, 2012-07
Description: n/a
M.S. in Civil Engineering, July 2012

$THE CHARACTERIZATION FOR B2 STRUCTURE AND L2\ STRUCTURE IN THE AG-MG AND AG-MG-IN SYSTEM$

Title: THE CHARACTERIZATION FOR B2 STRUCTURE AND L2\ STRUCTURE IN THE AG-MG AND AG-MG-IN SYSTEM
Creator: Kim, Do Hyung
Date: 2013, 2013-05
Description: The concentration of point defects and the long range order for ordered B2 AgMg alloys, quenched from 973K, was investigated by statistical...
Show moreThe concentration of point defects and the long range order for ordered B2 AgMg alloys, quenched from 973K, was investigated by statistical thermodynamic modeling, powder X-Ray Diffractometery and diffraction simulation as a function of composition. The lattice parameter behavior on the Ag rich side are expectably having constitutional and thermal anti-site defects on both Ag and Mg sub-lattices, corresponding to the literature data. On the other hand, the Mg rich side has substantially thermal vacancy defects based on the lattice parameter data which shows lower, compared with previously reported data. Concentration of the equilibrium point defects at 973K was calculated from two thermodynamic models, where the Ag rich side was based on the constitutional and thermal anti-site defect formation and the Mg rich side was based on the hybrid defect formation consisting of vacancy, Mg and Ag anti-site defects The experimental long range order at 973K, determined from the integrated intensity ratio of (100) super-lattice reflection to (200) fundamental reflection, is in quite good agreement with the theoretical long range order at 973K based on the calculated integral intensities from the diffraction simulation with the equilibrium concentration of each point defect, obtained by two thermodynamic models. Furthermore, point defect hardening coefficients on both sides of stoichiometry were determined by the measurement of the Vickers hardness as a function of the equilibrium concentration of the main point defects deduced from two thermodynamic models. The hardening coefficient is G/16 for the Ag rich side with respect to Ag anti-site defects and G/3.1 for the Mg rich side with respect to vacancy defects. Also, two hardening coefficients are corresponding to the empirical correlation for the several binary B2 intermetallic compounds with anti-site defects (G/9 to G/85) xvi and vacancy defects (G/3 to G/4). This suggests that the elastic size effect on the Ag rich side is the primary hardening mechanism due to constitutional and thermal Ag anti-site defects while the Mg rich side is likely to have the elastic modulus effect due to constitutional and thermal vacancy defects. It is also indicated that the vacancy defect is more significant hardener than Ag anti-site defects for the ordered B2 AgMg intermetallic system. The partial liquidus projection in the Ag-Mg-In ternary system was established by the primary phase and liquidus temperature, using the Scanning Electron Microscopy, Energy Dispersive Spectroscopy and Differential Scanning Calorimetry. The results showed that the AgMg1-xInx phase of the Ag-Mg-In ternary system has a large primary solidification field up to 90 at.% of In, so that most ternary invariant reactions of the In rich field must be formed beyond 90 at.% of In. The liquid-solid schematic reactions in the Ag rich field were experimentally confirmed, but those of the In rich side have not been established. Furthermore, the ordering phase transition and melting temperature of the Heusler phase AgMg1-xInx alloys were investigated using Differential Scanning Calorimetry, Scanning Electron Microscopy, and powder X-Ray Diffractometery. The DSC results indicated that the melting temperature decreased with increasing the In composition, but a thermal peak for the ordering phase transition was not detected due to either a very small heat of transition or a second order transformation. The XRD results showed that the L21 structure of the Heusler phase was observed for the 15 at.% of In alloy and the degree of order of L21 structure continuously increased with the In composition, resulting from the (111) super-lattice intensity with respect to the In composition. The L21 structure ordering of the 15 at.% of In and 20 at.% of In system xvii was gradually decreased with increasing the annealing temperature, corresponding to decreasing the (111) super-lattice intensity and the long rang order parameters of the L21 structure. These XRD behaviors suggest that the L21/B2 ordering transformation phenomena is a second order transformation with respect to temperature.
PH.D in Material Science and Engineering, May 2013
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Title: GENERAL FACTORS IN EMPLOYEE ENGAGMENT SURVEYS
Creator: Mcdonald, Jordan C.
Date: 2017, 2017-07
Description: There is growing recognition of the need to model general factors within the context of job attitude constructs and their effects in the...
Show moreThere is growing recognition of the need to model general factors within the context of job attitude constructs and their effects in the interpretation of employee engagement survey data. General factors are defined as latent variables that account for a substantial proportion of variance in multidimensional constructs and influence all subsets of items (Ree, Carretta & Teachout, 2015). The bifactor model has gained increased attention for its advantages in modeling multidimensional constructs, including improved fit and enabling the examination of the unique contributions of the general and specific factors for prediction (Chen, Hayes, Carver, Laurenceau, & Zhang, 2012; McAbee, Oswald, & Connelly, 2014; Gignac, 2016; Reise, 2012). The aim of the current study was to apply the advantages of the bifactor model in the employee engagement survey context in predicting employee turnover compared to alternative factor models (i.e., correlated factors model). The current research consisted of two studies: the first was conducted to determine the factor model that balanced parsimony and plausibility by cross-validating the model’s generalizability with a different set of data sharing the same survey items. The second study compared the factors of the bifactor model—including the general factor—and the factors of the correlated factors model in predicting employee turnover. Accounting for the general factor in employee engagement surveys resulted in different factors being significantly to turnover compared to when the general factor was not modeled. Practical implications and directions for future research are discussed.
M.S. in Psychology, July 2017
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Title: INVESTIGATION OF BI-IN-SN AND BI-IN-SN-GA AS PHASE CHANGE MATERIALS
Creator: Huynh, Hong Trang
Date: 2012-05-02, 2012-07
Description: Phase change energy storage is one of the most effective ways to store thermal energy. The difference between metallic phase change materials ...
Show morePhase change energy storage is one of the most effective ways to store thermal energy. The difference between metallic phase change materials (PCMs) and organic and inorganic PCMs is discussed. Bi-In-Sn and Bi-In-Sn-Ga alloys with near eutectic compositions were analyzed using DSC, X-Ray, EDS and metallography to establish the alloy properties. An attempt was made to package the alloy in metallic and non-metallic foams and various tests such as infiltration and cycling tests were conducted to test the feasibility of various containment materials. These PCM alloys were applied in a prototype cooling system of electronic devices for better heat dissipation than conventional heat sinks. Tests were conducted to measure the effectiveness of the alloys. Different designs were suggested for the containment of the alloy.
M.S. in Mechanical, Materials, and Aerospace Engineering, July 2012
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Title: Computational Techniques for Wind Turbine Power Prediction
Creator: Goyal, Udit
Date: 2011-11-28, 2011-12
Description: Wind energy is expected to play an important role in meeting the ever- increasing energy requirements and reducing our dependence on...
Show moreWind energy is expected to play an important role in meeting the ever- increasing energy requirements and reducing our dependence on conventional sources of energy. Wind turbines are broadly classfied as horizontal-axis and vertical-axis depending upon the orientation of the rotor shaft relative to the wind direction. Considerable research has been carried out on horizontal-axis wind turbines, which today are sophisticated and efficient electro-mechanical systems. Continuous research and development in areas of electronics, controls and instrumentation aids in the advancements of this technology. From an aerodynamic point of view the Betz limit is known to impose theoretical limit on the power extraction of propellers. The momentum balance equations show that the maximum of 59.3 percent of free-stream energy can be extracted by propellers. This limit, however is not well de fined, particularly when considering diff user and nozzle-augmented wind turbines with local flow accelerations. In this study the actuator disk approach is used to model the momentum loss across a wind turbine rotor and simulate the Betz limit using Fluent software. This approach is subsequently applied to study the coefficient of performance expected from dif user and nozzle-augmented wind turbines. Vertical-axis wind turbines, on the other hand, are still not completely understood in terms of blade aerodynamics and are the focus of various research studies. Large variations in angle of attack and wake evolution downstream of the blade have a time-dependent e ffect on the blade forces, instantaneous torque and hence the coefficient of power of the turbine. Since Navier-Stokes solutions for vertical- axis wind turbines are expensive and complicated, various low-cost models have been developed based on momentum balance such as single, double and double multiple- streamtube formulations. These models, however, use static lift and drag data for the airfoils as inputs, neglecting the unsteady e ffects on aerodynamic coefficients. In the present study, an alternative approach based on the panel method is explored further for developing a low-cost computational method for simulating the aerodynamics of vertical-axis wind turbines. At each time step an airfoil is represented as a combination of source and vortex distributions which induce a potential in the flow fi eld. A time-stepping mechanism is implemented satisfying the Kutta and the Kelvin Helmholtz condition for the wake evolution behind the rotating blades. The e ffect of this vortex evolution on the aerodynamic forces on the airfoil is studied, focusing on the coefficient of performance (Cp) of the blade. Results show a decrease in Cp values till the wake attains a quasi steady state. A comparison study is performed with other computational models, showing the importance of the wake evolution in time. An optimization of the blade pitch angle is also performed by defi ning a composite variable pitch function in order to improve the torque and hence the instantaneous power from the blades.
M.S. in Mechanical and Aerospace Engineering, December 2011
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Title: CHICAGO’S REFORMATIVE URBAN ARMATURES HYPERACTIVE INFRASTRUCTURAL LINKAGES
Creator: Osborne, Zachary C.
Date: 2015, 2015-12
Description: This research will project the impact of a new urban armature of logistics for the city of Chicago capable of improving the movement and...
Show moreThis research will project the impact of a new urban armature of logistics for the city of Chicago capable of improving the movement and experiences of people and goods throughout new hyperactive urban developments. Through the use of historical and contemporary precedence this new urban plan will address the continual shift in public domains, creating improved linkages and socially charged urban environments. As the inevitable densification of Chicago occurs a new network of connective infrastructure is required for creating new dynamic, three-dimensional public realms. The demand for such kinetic building models is caused by the mass influx of the creative-class returning to urban centers for both work and living. Consisting of a highly diverse set of programs, these new models for Chicago's west loop business district will focus on reconnecting the public to undiscovered urban layers. These hybrid developments break the mold of Chicago's modernist high rise tower allowing for mixing and overlapping of building programs, bringing strangers together in impromptu gathering spaces. Tiered circulation networks serve as the key infrastructural element facilitating these new socially engaging environments. Through the use of this tiered system primary circulation elements allow for the direct movements of private users and services while secondary and tertiary systems allows for pedestrians to penetrate "private" space fostering the interactions amongst a diverse a group of people. Within the new west loop district, the principles applied in creating vibrant urban atmospheres must be applied to internalized building programs, offering a variety of destination points throughout. Through the shaping of space by both generic and specific building forms the spaces in between become critical for the mixing of various characters. New urban armatures must be applied within these spaces providing the support for versatile and adaptable building programs and public spaces.
M.S. in Architecture, December 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: FEM-BASED MULTIPHYSICS MODELING OF CONTAMINATION AND REMEDIATION OF VARIABLY SATURATED SOILS
Creator: Miao, Tao
Date: 2015, 2015-05
Description: With the increasing awareness of environmental protection, the soil contamination has been a major problem in this industrial world. This...
Show moreWith the increasing awareness of environmental protection, the soil contamination has been a major problem in this industrial world. This study aims to develop numerical tools to simulate the soil pollution process and evaluate the effectiveness and efficiency of remediation solutions. First of all, a mathematical model was built to describe the pollutants (chemical species) transport phenomenon in soil, especially under unsaturated states. The model is developed based on mass conversation principle and two mechanisms were taken into account, including natural diffusion and convective flow. In order to obtain the flow velocity in soil, a variety of material parameters for soil such as permeability and hydraulic conductivity should be determined. The Richard’s equation, commonly used in formulating soil-water characteristic curves, was adopted to study moisture movement in the variably saturated soils. The model was applied to predict multiple pollutant species transporting in clayey, silty and sandy soils. Second, as a new coming method, electrokinetic remediation has been proven an effective and sustainable solution to clean up contaminated soil. Resulting from the added external electrical field, electroosmosis and electromigration were generated, which can remove pollutant ions from the polluted soil domain. A second model was built to evaluate cleaning up efficiency of electrokinetic solution, and then implemented to simulate remediation of soil contaminated by nuclear waste. The last part of this study aims to focus on another remediation solution. Bioremediation is becoming an effective method for treating soils or geo-materials contaminated by organic pollutants. Bioremediation can be defined as introduction of bacteria or fungi to foster degradation and removal of pollutants. The development of the third model for determining the mobility and growth of bacterial microorganisms are presented. This model captures three major propagation mechanisms in unsaturated soils, including natural diffusion, bacterial growth and convective flow. By adding relationship between pollutant degradation rate and bacteria concentration, the fourth model was applied to study the bioremediation remediation of petroleum pollution. Finite element method was conducted to solve mathematical models, which are partial differential equations of high nonlinearity. Based on computational results from the fist model, concentrations of various pollutants for both inorganic and organic can be predicted at any interested time in different types of soils under various environmental conditions. The second and fourth models can be used as numerical tools, which greatly facilitate the designing and evaluation of cleaning efficiency and effectiveness of electrokinetic remediation and bioremediation schemes, respectively.
M.S. in Civil, Architectural and Environmental Engineering, May 2015
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Title: WHO ONLINE DATES? PERSON VARIABLE PREDICTORS OF ONLINE DATING
Creator: Coppersmith, Jody
Date: 2012-04-23, 2012-05
Description: Due to social and technological changes, an increasing number of people are turning to online dating to seek romantic partners. People who...
Show moreDue to social and technological changes, an increasing number of people are turning to online dating to seek romantic partners. People who engage in online dating were initially thought to be socially anxious, shy individuals who became distressed in face-to-face interactions and used the Internet to compensate for their social challenges (McKenna & Bargh, 2000). However, more recent research has suggested this may no longer be the case (Valkenburg and Peters, 2007). The psychological literature has begun to address a wide range of person variables that may be related to online dating, but given the rapidly changing nature of the Internet, there is limited amount of understanding of the characteristics and motivations of individuals who engage in online dating. This study investigated the relationship between online dating and age, gender, fear of negative evaluation, introversion, perceived social support, general self-efficacy, and success finding dates face-to-face. Additionally, the belief that the online world reflects the offline world was assessed by examining the relationship between success finding dates face-to-faces and success finding dates online. The sample consisted of 110 participants: 55 participants who endorsed online dating and 55 individuals who did not endorse online dating. Results revealed that significant differences existed between online daters and non-online daters for age, success finding dates face-to-face, and perceived social support. However, only age and success finding dates face-to-face were significant predictors of who online dates. There was not a significant correlation between success findings dates face-to-face and success finding dates online. Overall, there appear to be limited differences in person characteristics of online daters and non-online daters. Online daters did not differ from non-online daters in social characteristics, one way or the other, as prior research has indicated. Rather, people of all types appear to be online dating. Despite the limitations of this study, these findings add to the growing online dating literature and support the case for an overall broad influence of technology on individuals’ lives, relationship formation, and relationship maintenance.
M.S. in Psychology, May 2012
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Title: JOINT UFH AND POWER CONTROL FOR EFFECTIVE WIRELESS ANTI-JAMMING COMMUNICATION
Creator: Xu, Kaihe
Date: 2012-04-27, 2012-05
Description: Jamming-resistant communication without pre-shared secrets has received extensive attention recently and is commonly tackled by utilizing the...
Show moreJamming-resistant communication without pre-shared secrets has received extensive attention recently and is commonly tackled by utilizing the technique of uncoordinated frequency hopping (UFH). However, existing approaches exhibit signi cant performance constraints due to the use of UFH at both the sender and the receiver sides. To improve the state of the art, in this paper we aim to signi cantly improve the performance of the anti-jamming system in the presence of a power-limited jammer. Speci cally, we for the rst time jointly consider UFH and power control and pose these two techniques into a uniform framework. The proposed approach utilizes online learning theory to determine both the hopping channels and the transmitting powers based on the history of channel status. By dividing the transmission power into multiple levels, the sender with a limited power budget is able to choose both the sending channels and the corresponding transmission power. The sender keeps re ning its knowledge of channel status to improve future channel selection and power allocation based on the feedback information from the receiver. We analytically show that, in presence of a power-limited jammer, the average transmission delay of our system is bounded by a xed value with high probability. Extensive simulations are conducted to demonstrate the e ectiveness of our scheme against various jamming attacks.
M.S. in Electrical Engineering, May 2012e
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Title: DRUG UPTAKE AND RELEASE BY STIMULI RESPONSIVE CYLINDRICAL AND SPHERICAL GELS
Creator: Ninawe, Pravin Ramkrishna
Date: 2011-08, 2011-07
Description: ABSTRACT Polymeric gels that undergo deformation upon appropriate changes in pH or temperature have considerable promise as drug delivery...
Show moreABSTRACT Polymeric gels that undergo deformation upon appropriate changes in pH or temperature have considerable promise as drug delivery vehicles. Uptake of drug macromolecules into swelling and non-swelling cylindrical and spherical gels and release of drug macromolecules from deswelling and non-deforming gels into a target fluid are investigated here. A mathematical model for gel-solution composite, a composite of a distributed parameter system (gel spheres or cylinders) and a lumped parameter system (surrounding solution), is developed. The polymer network displacement in swelling/deswelling gels is described by a stress diffusion coupling model. The analytical solution for network displacement is used to predict solvent intake by swelling gels, solvent efflux from deswelling gels, and changes in pressure, porosity and effective drug diffusivity resulting from network displacement. These in turn influence drug uptake during and after gel swelling and drug release from gel during and after gel deswelling. Numerical results illustrate benefits of gel swelling for drug loading and merits of different modes of drug release. Also, the attempt is made to analyze he effect of gel mesh size on the loading and release of large molecular weight drugs. Comparisons are made, as concerns drug uptake and drug release, with gels not subject to deformation. As a special case of application of the above developed model, we tried to simulate drug delivery to the human eye. Since, the therapeutic modalities for posterioreye diseases involve mostly interventions through the anterior eye, which are difficult for physicians and patients alike, sustained drug delivery to the posterior eye is gaining importance. A study for sustained delivery of an anti-VEGF agent (IgG) to the posterior eye from an implant, made of poly(N-isopropylacrylamide) (NIPAM) and placed episclerally, is presented. The model developed in the study is used to simulate the phase transition of the implant made of a thermo-sensitive polymer. The study xvii utilizes compartments for various eye tissues, with individual compartments considered to be completely mixed and drug transport between compartments occurring by one-dimensional diffusion. Further implementation of this model to predict drug concentrations in the eye tissues to arrive at optimum drug loading conditions is also presented here.
Ph.D. in Chemical Engineering, July 2011
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Title: MATRIX: MANY-TASK COMPUTING EXECUTION FABRIC FOR EXTREME SCALES
Creator: Rajendran, Anupam
Date: 2013-05-01, 2013-05
Description: Scheduling large amount of jobs/tasks over large-scale distributed systems play a significant role to achieve high system utilization and...
Show moreScheduling large amount of jobs/tasks over large-scale distributed systems play a significant role to achieve high system utilization and throughput. Today’s state-of-the-art job management/scheduling systems have predominantly Master/Slaves architectures, which have inherent limitations, such as scalability issues at extreme scales (e.g. petascales and beyond) and single point failures. In designing the next-generation job management system that addresses both of these limitations, we argue that we must distribute the job scheduling and management; however, distributed job management introduces new challenges, such as non-trivial load balancing. This thesis proposes an adaptive work stealing technique to achieve distributed load balancing at extreme scales, those found in todays’ petascale systems towards tomorrow’s exascale systems. This thesis also presents the design, analysis and implementation of a distributed execution fabric called MATRIX (MAny-Task computing execution fabRIc at eXascales). MATRIX utilizes the adaptive work stealing algorithm for distributed load balancing and distributed hash tables for managing task metadata. MATRIX supports both high-performance computing (HPC) and many-task computing (MTC) workloads. We have validated it using synthetic workloads up to 4K-cores on a IBM BlueGene/P supercomputer. Results show that high efficiencies (e.g. 90%+) are possible with certain workloads. We study the performance of MATRIX in depth, including understanding the network traffic generated by the work stealing algorithm. Simulation results are presented up to 1M-node scales which show that work stealing is a scalable and efficient load balancing approach for many-core architectures to extreme-scale distributed systems.
M.S. in Computer Science, May 2013
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Title: MAXIMIZATION OF SYSTEM UTILITY VALUE FOR TIME-SENSITIVE APPLICATIONS
Creator: Li, Shuhui
Date: 2014, 2014-12
Description: Many applications are time-sensitive in the sense that the usefulness or the quality of their end results depends on their completion time....
Show moreMany applications are time-sensitive in the sense that the usefulness or the quality of their end results depends on their completion time. Examples of this type of applications are threat detections in air defense systems [97], radar trackings [36, 85], mobile navigations by Google [79, 44], and online gaming by Nintendo [38], to name a few. Take the threat detection application as an example, clearly, the earlier a threat is detected, the higher utility the application provides, as earlier detection provides more time to eliminate the threat [97]. This demonstrates the time-sensitivity of its utility. Here, the term `utility' means the actual bene t that accrues from the delivery of services [16]. The dependence between an application's accrued utility and its completion time is often modeled by a Time Utility Function (TUF). Apparently, when a system has multiple time-sensitive applications competing for the resources, a question arises: how to schedule their execution orders such that the system can yield maximal accrued utility? This thesis is to address the question. In this thesis, two categories of scheduling problems for time-sensitive applications are investigated: single-task applications in uni-processor systems and parallel multi-task applications in multi-processor systems. For the rst category, a two-TUF application model with given execution time is introduced and two scheduling algorithms for this model are proposed. Di erent from the conventional one-TUF model which only considers the gain utility, the developed model can deal with both the gain and the penalty utilities. The model is further extended to cope with applications whose exact execution times are not known at a priori, rather only their probabilistic execution time distributions are known. For applications with variable execution times, the di culty is how to make judicious decisions about when to start, continue or abort the applications. For the second category, i.e., for parallel multi-task applications in multi-processor systems, di erent from the widely investigated sequential multi-task applications, a parallel multi-task application's execution can have both spatial and temporal in uence on other applications. We propose a metric to measure the spatial-temporal interference among parallel multi-task and time-sensitive applications with respect to accrued utility. Based on the metric, a 2-approximation algorithm is introduced for systems operate in discrete time domains and its lower bound of system total accrued utility value is proved. We also develop a heuristic scheduling algorithm to maximize system's total accrued utility value for continuous time systems. Finally, the thesis discusses how methodologies developed in the thesis can be applied to reduce system's operational cost without sacri cing applications' quality of service. We propose a model to bridge together two orthogonal scheduling criteria, i.e., the system operational cost and application response time, and solve the problem by transforming it to a system accrued utility value optimization problem. The research uses both theoretical and experimental approaches. Theorems and lemmas are developed to provide the foundations for our solutions, and at the same time, extensive experiments are conducted to empirically evaluate the performances of the developed solutions.
Ph.D. in Computer Science, December 2014
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Title: ARCHITECTURE FOR COLLABORATIVE CREATIVITY - SPACE WE-Q: SPACE INTELLIGENCE EMPOWERING CREATIVE WE CULTURE IN LEARNING-DRIVEN ENVIRONMENTS
Creator: Mor-Avi, Anat
Date: 2020
Description: Changes in societal culture, along with research on how we learn, challenge current architectural solutions. Education’s shifting paradigms...
Show moreChanges in societal culture, along with research on how we learn, challenge current architectural solutions. Education’s shifting paradigms align with these changes and move teaching strategies from teacher-centered to learner-centered, and from formal and passive, to informal and active modes. Another shift emphasizes collaboration and participatory creativity, which evolve the idea of the “collective,” or “We” versus “I” scenarios. In addition, studies show that creativity flourishes in specific contradictory performances. Supporting these reported changes, new knowledge, and paradigm shifts, this research studied how an active, adaptive architectural design approach might emerge into the learning and creative processes. Evidence indicates that “design and space do matter,” particularly in learning- and working-driven domains. Empirical research has been weak in addressing this understanding relative to architectural solutions, affordances, behaviors, and emotions, promoting collaborative creativity. This research aimed to investigate patterns of architectural affordances believing to impact and empower collaborative cultures and behaviors in learning environments (“WE CULTURE”), specifically motions and emotions. A Mixed-method research design was conducted, using two techniques: (a) a content analysis of awarded learning and working environments, and (b) a post-occupancy evaluation using ethnographic techniques to study the Kaplan Innovation Institute at the Illinois Institute of Technology in Chicago, Illinois, USA. In an effort to provide an applied design study, a visual pattern language related to cultures of learning, environment behavior, and emotions was developed. The pattern language is the platform for designing intelligent spaces, SPACE WE-Q, promoting collaborative behaviors, and creativity through adaptive and behavior-based systems of active affordances. SPACE WE-Q offers a planned adaptive system for unplanned creative processes that emerges into learning and suggesting a new relationship between architecture and education, between architects and users, and between users and space.
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Title: Laser Powder Bed Fusion Of Cost-Effective Non-Spherical Ti-6Al-4V Powder
Creator: Asherloo, Mohammadreza
Date: 2023
Description: This comprehensive research delves into the intricate dynamics of Laser Powder Bed Fusion (L-PBF) of Ti-6Al-4V powders, emphasizing the...
Show moreThis comprehensive research delves into the intricate dynamics of Laser Powder Bed Fusion (L-PBF) of Ti-6Al-4V powders, emphasizing the potential of non-spherical, hydride-dehydride (HDH) powders as a cost-efficient alternative to traditional spherical powders. The study systematically explores the interplay between powder morphology, granulometry, and various post-processing treatments in shaping the resultant microstructure, porosity, and mechanical properties of L-PBF fabricated Ti-6Al-4V components.Initial investigations focused on the flowability, packing density, and resultant density of L-PBF parts using HDH powders with varying size distributions. Through meticulous optimization of laser parameters, parts with a relative density exceeding 99.5% were achieved, even at production rates 1.5–2 times higher than conventional LPBF processes. Dynamic synchrotron X-ray imaging provided insights into laser-powder interactions, revealing key mechanisms of porosity formation associated with HDH powders. Further microstructural examinations highlighted the formation of columnar β grains with acicular α/α′ phases in the as-built condition. Mechanical tests, including fatigue assessments under fully-reversed tension-compression conditions, revealed the critical role of surface roughness in fatigue performance. Notably, mechanical grinding significantly improved fatigue strength, especially in the high cycle fatigue region, by eliminating surface micro-notches. X-ray diffraction analyses further elucidated the stress and micro-strain profiles, offering insights into the material's deformation mechanisms. A pivotal discovery was the presence of α/α′ on prior β/β grain boundaries, challenging the prevailing notion that high cooling rates in L-PBF preclude β/β grain boundary variant selection. Electron backscatter diffraction and synchrotron X-ray imaging illuminated the role of powder characteristics in locally modulating cooling rates, leading to β/β grain boundary α′ lath growth. Lastly, the research underscored the multifaceted interdependencies among contouring, powder granulometry, Hot Isostatic Pressing (HIP), and mechanical surface treatments. A pronounced increase in sub-surface porosities was identified when contouring was combined with fine powder granulometry. However, post-HIP treatments induced a phase transformation from martensitic α′ to a basket-weave α+β microstructure, enhancing the material's fatigue resistance to levels comparable to wrought Ti-6Al-4V. In summation, this doctoral research offers a holistic understanding of the L-PBF process for Ti-6Al-4V, emphasizing the viability of non-spherical HDH powders and providing a roadmap for parameter optimization, defect minimization, and mechanical property enhancement in L-PBF-fabricated Ti-6Al-4V structures.
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Title: Case Study: A Comparison of Pedagogical Content Knowledge Between Coaches and Coaches/Mentees
Creator: Barone, Ana MargaritaSalinas
Date: 2024
Description: This multiple case study dissertation aimed to examine one of the domains of pedagogical content knowledge, knowledge of content and students,...
Show moreThis multiple case study dissertation aimed to examine one of the domains of pedagogical content knowledge, knowledge of content and students, between different types of elementary coaches and between coach and their respective collaborating teachers. It also investigated the impact a coaches’ background experiences have on the dynamic between coaches and teachers and the perceptions' teacher have on the effectiveness of coaching. The theoretical framework used in this qualitative study was Ball, Thames, and Phelps’ (2008) definition of PCK. Data was collected from six coaches–four instructional coaches and two math coaches–and eleven k-5th grade teachers. Data collection involved a survey, LMT assessment, and semi-structured interviews, and a thematic analysis method was conducted. The findings from the cross-case analysis resulted in ten themes, with the majority having multiple categories. One finding to one of the research questions was that there were no differences in knowledge of content and students between mathematics coaches and general instructional coaches, but other areas to further investigate emerged. Another finding was that coaches were either within the same capacity as their respective teachers or had extra knowledge of content and students. Although the majority of the coaches’ knowledge of content and students was at a higher level according to their LMT score, it does not necessarily mean that coaches are working with teachers in improving knowledge of content and students. In addition, more research is recommended in creating a pedagogical content knowledge instrument that is specific for coaches.
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Title: Case Study: A Comparison of Pedagogical Content Knowledge Between Coaches and Coaches/Mentees
Creator: Barone, Ana MargaritaSalinas
Date: 2024
Description: This multiple case study dissertation aimed to examine one of the domains of pedagogical content knowledge, knowledge of content and students,...
Show moreThis multiple case study dissertation aimed to examine one of the domains of pedagogical content knowledge, knowledge of content and students, between different types of elementary coaches and between coach and their respective collaborating teachers. It also investigated the impact a coaches’ background experiences have on the dynamic between coaches and teachers and the perceptions' teacher have on the effectiveness of coaching. The theoretical framework used in this qualitative study was Ball, Thames, and Phelps’ (2008) definition of PCK. Data was collected from six coaches–four instructional coaches and two math coaches–and eleven k-5th grade teachers. Data collection involved a survey, LMT assessment, and semi-structured interviews, and a thematic analysis method was conducted. The findings from the cross-case analysis resulted in ten themes, with the majority having multiple categories. One finding to one of the research questions was that there were no differences in knowledge of content and students between mathematics coaches and general instructional coaches, but other areas to further investigate emerged. Another finding was that coaches were either within the same capacity as their respective teachers or had extra knowledge of content and students. Although the majority of the coaches’ knowledge of content and students was at a higher level according to their LMT score, it does not necessarily mean that coaches are working with teachers in improving knowledge of content and students. In addition, more research is recommended in creating a pedagogical content knowledge instrument that is specific for coaches.
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Title: A Limited Case Study: Perspectives of Students, High School Teachers, and College Instructors About Advanced Placement Mathematics Courses
Creator: Joseph, DeJuana V.
Date: 2023
Description: ABSTRACTBackground. The underrepresentation of Black and Latinx students in STEM is highlighted due to structural impediments. Although AP...
Show moreABSTRACTBackground. The underrepresentation of Black and Latinx students in STEM is highlighted due to structural impediments. Although AP mathematics classes are being introduced as a solution, students from underprivileged schools continue to confront challenges. The study project seeks to investigate the obstacles associated with teaching AP mathematics courses in disadvantaged high schools and to gather perspectives from various stakeholders.Methodology. The study employs qualitative one-on-one interviews and an interpretive research paradigm. The sample comprises mathematics faculty, first-year college students, high school AP math teachers, and one high school student. Thematic analysis is used and ethical considerations are taken into account. Limitations include time and resource constraints, a small sample size, and potential inconsistencies in participant responses.Results and Findings. AP mathematics classes may inspire students to continue STEM in college, yet obstacles such as time constraints and knowledge gaps exist. Students' employment choices are influenced by their own interests and abilities. High school math teachers and college professors highlight algebraic skills as crucial for success in college mathematics, particularly in calculus classes.Discussion. The STEM enrollment problem does not only affect minority students; AP math can be a pathway for all kids. Improving AP math readiness for all students is critical for addressing the STEM professional shortage. It is essential to use extra measures to increase student interest in STEM. Strong foundational algebraic knowledge is required for success in higher education, necessitating stakeholders to focus on improving STEM enrollment and completion rates.
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Title: Evaluation of Bridge Abutment Slope Protection at Stream Crossings
Creator: Wang, Peng
Date: 2023
Description: Extensive research has revealed that scour and flooding contribute to over 50% of bridge failures in the United States, with scour-induced...
Show moreExtensive research has revealed that scour and flooding contribute to over 50% of bridge failures in the United States, with scour-induced failures alone causing the collapse of 20-100 over-water bridges annually out of a total population of approximately 504,000 bridges. Within Wisconsin, a significant number of bridges, specifically over 1200, have been identified as scour-critical, with 200 of them experiencing slope instability issues.This study focuses on the problematic bridge sites in Wisconsin, particularly examining the underperformance of abutment slopes. To identify and document these problematic bridges, a comprehensive survey was conducted, followed by site visits. Subsequently, a thorough Limit Equilibrium Method (LEM) simulation was carried out based on an investigated bridge. The simulation results indicate that the infiltration of water into the slope berm areas significantly decreases slope stability due to seepage forces. Furthermore, the absence of riprap toe protection can result in overall slope failure. The implementation of concrete pouring to address riprap scoring has proven unreliable, leading to frequent failures.Additionally, simulations were performed for grouted riprap, slope walls, grouted tiebacks, and piles. The results demonstrate their potential to enhance slope safety, with their suitability requiring careful evaluation. Notably, a simulation comparing a 1:2 slope design with a 1:1.5 slope inclination reveals that the former significantly improves slope safety.In Chapter 5, a comprehensive life cycle cost analysis is conducted, comparing the 1:2 slope design to the 1:1.5 design. The analysis reveals that the 1:2 design method is more cost-effective over a 60-year study period.In conclusion, this research provides valuable insights into the assessment and mitigation of abutment slope protection issues in Wisconsin. The findings emphasize the importance of considering seepage forces, appropriate riprap installation, and alternative stabilization measures together with a comprehensive life cycle cost analysis. The research contributes to enhancing slope safety and informs decision-making processes for bridge design and maintenance.
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Title: Laser Powder Bed Fusion Of Cost-Effective Non-Spherical Ti-6Al-4V Powder
Creator: Asherloo, Mohammadreza
Date: 2023
Description: This comprehensive research delves into the intricate dynamics of Laser Powder Bed Fusion (L-PBF) of Ti-6Al-4V powders, emphasizing the...
Show moreThis comprehensive research delves into the intricate dynamics of Laser Powder Bed Fusion (L-PBF) of Ti-6Al-4V powders, emphasizing the potential of non-spherical, hydride-dehydride (HDH) powders as a cost-efficient alternative to traditional spherical powders. The study systematically explores the interplay between powder morphology, granulometry, and various post-processing treatments in shaping the resultant microstructure, porosity, and mechanical properties of L-PBF fabricated Ti-6Al-4V components.Initial investigations focused on the flowability, packing density, and resultant density of L-PBF parts using HDH powders with varying size distributions. Through meticulous optimization of laser parameters, parts with a relative density exceeding 99.5% were achieved, even at production rates 1.5–2 times higher than conventional LPBF processes. Dynamic synchrotron X-ray imaging provided insights into laser-powder interactions, revealing key mechanisms of porosity formation associated with HDH powders. Further microstructural examinations highlighted the formation of columnar β grains with acicular α/α′ phases in the as-built condition. Mechanical tests, including fatigue assessments under fully-reversed tension-compression conditions, revealed the critical role of surface roughness in fatigue performance. Notably, mechanical grinding significantly improved fatigue strength, especially in the high cycle fatigue region, by eliminating surface micro-notches. X-ray diffraction analyses further elucidated the stress and micro-strain profiles, offering insights into the material's deformation mechanisms. A pivotal discovery was the presence of α/α′ on prior β/β grain boundaries, challenging the prevailing notion that high cooling rates in L-PBF preclude β/β grain boundary variant selection. Electron backscatter diffraction and synchrotron X-ray imaging illuminated the role of powder characteristics in locally modulating cooling rates, leading to β/β grain boundary α′ lath growth. Lastly, the research underscored the multifaceted interdependencies among contouring, powder granulometry, Hot Isostatic Pressing (HIP), and mechanical surface treatments. A pronounced increase in sub-surface porosities was identified when contouring was combined with fine powder granulometry. However, post-HIP treatments induced a phase transformation from martensitic α′ to a basket-weave α+β microstructure, enhancing the material's fatigue resistance to levels comparable to wrought Ti-6Al-4V. In summation, this doctoral research offers a holistic understanding of the L-PBF process for Ti-6Al-4V, emphasizing the viability of non-spherical HDH powders and providing a roadmap for parameter optimization, defect minimization, and mechanical property enhancement in L-PBF-fabricated Ti-6Al-4V structures.
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