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Title: CHARACTERIZATION OF A CHROMIUM VANADIUM STEEL IN A HAND TOOL APPLICATION
Creator: Cease, Herman
Date: 2011-04-23, 2011-05
Description: A chromium vanadium steel is characterized for use in a hex wrench hand tool application. The application justi es the need for a high...
Show moreA chromium vanadium steel is characterized for use in a hex wrench hand tool application. The application justi es the need for a high strength and ductile steel. The standard steel alloy used for hex wrenches is 8650. An alternative lower cost steel alloy, 61B60CrV, is considered for the hex wrench hand tool application. The microstructure achieved is tempered martensite. First martensite is formed to create a high strength but brittle material. Then the martensite is reheated and tem- pered to improve the ductility of the material. Both 8650 and 61B60CrV alloys are thermally processed in the same way to create the tempered martensitic structure. The mechanical properties of the proposed steel is evaluated and compared to that of the standard 8650 steel alloy. The 61B60CrV alloy evaluation includes torsion test- ing, hardness and hardenability measurements, and grain size determination. The 61B60CrV alloy is proven to meet the hex wrench hand tool mechanical requirements with a tempered martensitic microstructure. During Jominy hardness testing of the 61B60CrV alloy, it is determined that the hardness requirements are met for a wide range of microstructures. Samples of the 61B60CrV alloy are austempered for di er- ent durations then quenched to room temperature to create samples with di erent amounts of mixed microstructures of bainite and martensite. A range of mixed mi- crostructures are shown to meet the strength, ductility, and hardness requirements for the hex wrench hand tool application without tempering.
Ph.D. in Material Science and Engineering, May 2011
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Title: PEDESTRIAN URBANISM: THE CULTURAL IMPACTS OF WALKABLE COMMUTES AND TRANSIT USE IN CHICAGO (UNITED STATES), PARIS (FRANCE), AND SEOUL (KOREA)
Creator: Jeong, Hyesun
Date: 2016, 2016-12
Description: In the past several decades, followers of Jane Jacobs have sought to codify her concept of “eyes on the street.” Jacobs used Greenwich Village...
Show moreIn the past several decades, followers of Jane Jacobs have sought to codify her concept of “eyes on the street.” Jacobs used Greenwich Village in New York City to illustrate how her concept could be enhanced through the density and diversity of mixed neighborhoods. This study’s core hypothesis emphasizes density, mixed use, and the cultural pattern of Bohemia on walkability. Mainly based on Jacobs’s argument, this study encourages urban development and neighborhood vitality, and then expands it with walking, bicycling, and public transit use. The study uses a comparative analysis of Chicago (USA), Paris (France), and Seoul (Korea) to examine public policy towards a walkable city in contexts where this policy adjusts to local neighborhoods. The study redefines the concept of Bohemia by numerically codifying and measuring it as a cultural variable together with other urban variables to evaluate their relationship to commuting choice and transit ridership in three cities and their countries. The findings from the statistical analysis show that Bohemia and the presence of the arts are strongly associated with non-auto commuting modes and public transit ridership.
Ph.D. in Architecture, December 2016
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Title: MAKING GOOD DECISIONS: THE ROLE OF TEAM PERSONALITY DIVERSITY AND GROUP POLARIZATION
Creator: Watson, Jeremy Beau
Date: 2014, 2014-05
Description: Making high quality decisions is central to organizations in order to remain competitive, increase productivity, quality, and/or remain...
Show moreMaking high quality decisions is central to organizations in order to remain competitive, increase productivity, quality, and/or remain responsive to customers. Most often, teams are responsible for making vital decisions and decision accuracy is key to obtaining desired outcomes. This study examined the role of team personality diversity as it pertains to decision quality. Additionally, a common phenomenon known as group polarization was studied with regard to cooperative and competitive attitudes as a potential important process. Using several decision scenarios and the Lost on the Moon task, 279 individuals in teams of three (n = 93 teams) participated in a laboratory study to investigate the relationship between team personality diversity, group polarization of cooperative/competitive attitudes, and decision quality. Results indicated that team agreeableness diversity was positively related to group polarization, and team openness diversity was negatively related to decision quality. Previous research, implications, and limitations to this study are also discussed.
PH.D in Psychology, May 2014
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Title: ADAPTIVE QUASI-MONTE CARLO CUBATURE
Creator: Jimenez Rugama, Lluis Antoni
Date: 2016, 2016-12
Description: In some definite integral problems the analytical solution is either unknown or hard to compute. As an alternative, one can approximate the...
Show moreIn some definite integral problems the analytical solution is either unknown or hard to compute. As an alternative, one can approximate the solution with numerical methods that estimate the value of the integral. However, for high dimensional integrals many techniques suffer from the curse of dimensionality. This can be solved if we use quasi-Monte Carlo methods which do not suffer from this phenomenon. Section 2.2 describes digital sequences and rank-1 lattice node sequences, two of the most common points used in quasi-Monte Carlo. If one uses quasi-Monte Carlo, there is still another problem to address: how many points are needed to estimate the integral within a particular absolute error tolerance. In this dissertation, we propose two automatic cubatures based on digital sequences and rank-1 lattice node sequences that estimate high dimensional problems. These new algorithms are constructed in Chapter 3 and the user-specified absolute error tolerance is guaranteed to be satisfied for a specific set of integrands. In Chapter 4 we define a new estimator that satisfies a generalized tolerance function and includes a relative error tolerance option. An important property of quasi-Monte Carlo methods is that they are effective when the function has low effective dimension. In [1], Sobol’ defined the global sensitivity indices, which measure what part of the variance is explained by each dimension. We can use these indices to measure the effective dimensionality of a function. In Chapter 5 we extend our digital sequences cubature to estimate first order and total effect Sobol’ indices.
Ph.D. in Applied Mathematics, December 2016
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Title: BELIEFS AND CONTEXTUAL MEDIATORS AND MODERATORS OF DISCRETIONARY WORKPLACE BEHAVIOR
Creator: Raad, Jason H.
Date: 2014, 2014-07
Description: The Theory of Planned Behavior (TPB) has been successfully used to link attitudes, subjective norms, and perceived behavioral control to the...
Show moreThe Theory of Planned Behavior (TPB) has been successfully used to link attitudes, subjective norms, and perceived behavioral control to the enactment of various behaviors in numerous situations; however, the TPB in not frequently used in organizational settings. Similarly, contextual factors may represent important moderating and mediating effects that have not been fully explored in prior TPB research. The current study employs the TPB in a healthcare setting to assess the use of Outcome Measures (OMs) by practicing clinicians. Two contextual mediators and a one contextual moderator were added to the standard TPB framework in an attempt to better explain the enactment of discretionary workplace behavior. Results suggest that TPB components are related to the discretionary use of Outcome Measures in clinical practice; however, results also suggest that hypothesized relationships between TPB factors may diverge significantly from those proposed in the original theory. Implications, limitations, and future directions are also discussed.
Ph.D. in Psychology, July 2014
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Title: GUARANTEED ADAPTIVE MONTE CARLO METHODS FOR ESTIMATING MEANS OF RANDOM VARIABLES
Creator: Jiang, Lan
Date: 2016, 2016-05
Description: Monte Carlo is a versatile computational method that may be used to approximate the means, μ, of random variables, Y , whose distributions are...
Show moreMonte Carlo is a versatile computational method that may be used to approximate the means, μ, of random variables, Y , whose distributions are not known explicitly. This thesis investigates how to reliably construct fixed width confidence intervals for μ with some prescribed absolute error tolerance, "a, relative error tolerance, "r or some generalized error criterion. To facilitate this, it is assumed that the kurtosis, , of the random variable, Y , does not exceed a user specified bound max. The key idea is to confidently estimate the variance of Y by applying Cantelli’s Inequality. A Berry-Esseen Inequality makes it possible to determine the sample size required to construct such a confidence interval. When relative error is involved, this requires an iterative process. This idea for computing μ = E(Y ) can be used to develop a numerical integration method by writing the integral as μ = E(f(x)) = RRd f(x)⇢(x)dx, where x is a d dimensional random vector with probability density function ⇢. A similar idea is used to develop an algorithm for computing p = E(Y) where Y is a Bernoulli random variable. All of the algorithms have been implemented in the Guaranteed Automatic Integration Library (GAIL).
Ph.D. in Applied Mathematics, May 2016
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Title: RISK SHIFTING, MANAGER SENTIMENT AND NEW INVESTMENT EFFICIENCY IN MANAGED FUTURES
Creator: Jiang, Cheng
Date: 2017, 2017-05
Description: This dissertation focuses on a subset of hedge fund, Commodity Trading Advisors (CTAs), which has grown in the past 35 years and highlighted...
Show moreThis dissertation focuses on a subset of hedge fund, Commodity Trading Advisors (CTAs), which has grown in the past 35 years and highlighted by its diversification benefit to traditional asset classes. I will study the risk-taking, market timing and market capacity of this type of hedge fund. I study the volatility of an extensive sample of live and defunct Commodity Trading Advisor funds from 1994 to 2013. Utilizing the gross-of-fee return, I document significant mean-reversion in volatility in the time series of CTA funds. I further examine the impact of performance on volatility shift, and find consistent evidence of risk tournament behavior, especially when the CTA industry is performing well. Moreover, the risk shifting of CTA managers depend upon both relative and absolute fund performance. The practice of this conditional risk shifting has benefitted the fund managers at the cost of fund investors. I estimate the average benefit to manager's return income and the average cost to investor's Sharpe ratio. My findings provide a first comprehensive evidence on the risk strategy of CTA funds, suggesting that managerial career concerns do not eliminate the moral hazard problem in the CTA space. The asymmetric nature of performance-based compensation in hedge funds produces a strong incentive for risk-shifting, but empirical research presents mixed evidence of risk-seeking behavior. The driver of the change in risk can also be related to other reasons other than incentive fees. I introduce a behavioral regime-switching model of fund manager sentiment in which Bayesian learning is used to update beliefs about market environment in an effort to predict future performance and anticipate market moves. I use a subset of hedge funds in the managed futures industry between 1994 and 2014 and find that the risk-taking behavior of fund managers is influenced by human emotions but in two distinctly different ways. The capital flow to hedge funds has well-known price pressure and smart money effect. This paper studies the capital flows impact on CTA future performance. It had been observed both in mutual funds and hedge funds that mangers scale their existing holding up or down by using new capital inflow rather than trade new positions. This strategy will generate positive returns for the funds due to the price pressure effect. It is interesting whether it will exist in managed future space. I use Vector auto-regression (VAR) to evaluate a system of 2 variables: capital inflow and future performance. If the relationship is negative, one possible reason could be the market impact that erodes the profit generated by price pressure. Therefore, I will implement a market impact test that investigate the market capacity in terms of Sharpe ratio and t-statistics of alpha.
Ph.D. in Management Science, May 2017
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Title: NETWORK CONGESTION / RESOURCE ALLOCATION GAME
Creator: Shin, Junghwan
Date: 2013, 2013-12
Description: We first consider the K-user(player) resource allocation problem when the resources or strategies are associated with homogeneous functions....
Show moreWe first consider the K-user(player) resource allocation problem when the resources or strategies are associated with homogeneous functions. Further, we consider the K-user(player) matroid resource allocation problem satisfying the specified requirements of the users, which are maximal independent sets of a matroid. The objective is to choose strategies so as to minimize the average maximum cost incurred by a user where the cost of a strategy is the sum of the costs of the elements comprising the strategy. For k commodity networks with heterogeneous latency functions, we consider the price of anarchy (PoA) in multi-commodity selfish routing problems where the latency function of an edge has a heterogeneous dependency on the flow commodities, i.e. when the delay is dependent on the flow of individual commodities, rather than on the aggregate flow. Further we consider the price of anarchy (PoA) in multi-commodity atomic flows where the latency function of an edge has a heterogeneous dependency on the flow commodities, i.e. when the delay is dependent on the flow of individual commodities, rather than on the aggregate flow. Lastly, we show improved bounds on the price of anarchy for uniform latency functions where each edge of the network has the same delay function. We prove bounds on the price of anarchy for the above functions. Our bounds illustrate how the PoA is dependent on θ and the coefficients gij . At the end, we consider security aspects of network routing in a game-theoretic framework where an attacker is empowered with the ability for intrusion into edges of the network; on the other hand, the goal of the designer is to choose routing paths.
PH.D in Computer Science, December 2013
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Title: The Relationship Between Default and Volatility and Its Impact on Counterparty Credit Risk
Creator: Yang, Jiarui
Date: 2012-07-16, 2012-07
Description: This thesis presents a uni ed framework for studying the impact of the correlation between interest rate volatility and counterparty default...
Show moreThis thesis presents a uni ed framework for studying the impact of the correlation between interest rate volatility and counterparty default probability on the credit risk of collateralized interest-rate derivative contracts. A defaultable term structure model is proposed in which the default risk is correlated with interest rate volatility. In particular, an existence and uniqueness theorem of this model is proved. The pricing formula of credit derivatives under the proposed model is derived and the stochastic interest rate model and credit model are calibrated together . Finally, given all the parameters calibrated by the unscented Kalman lter, a sensitivity analysis of the impact of the correlation between interest rate volatility and a counterparty's default probability on the credit risk of collateralized interest-rate derivative contracts is presented.
Ph.D. in Applied Mathematics, July 2012
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Title: STUDIES ON CONNECTIVE AND NEUROLOGICAL TISSUES IN RELATION TO DISEASE
Creator: Madhurapantula, Rama Sashank
Date: 2015, 2015-12
Description: The structure of connective tissue is of great importance for homeostasis of the cells present within it. Pathologies leading to changes in...
Show moreThe structure of connective tissue is of great importance for homeostasis of the cells present within it. Pathologies leading to changes in the structure of the extracellular matrix (ECM), in particular collagen have been shown to play a pivotal role in the progression of various diseases. Similarly, changes in the structure of specific elements in neurological tissues, such as myelin, have been shown to elicit adverse responses to injury. This thesis explores two main aspects: 1) the structural changes brought about by high sugar concentrations, much similar to that found in diabetic patients, to the structure of type I collagen and 2) possible effects of traumatic brain injury (TBI) to the structure of neurons in rat brains. Specific changes in the structure and packing of collagens in various tissues could be potential therapeutic targets to control the progression of related diseases. However, the information available on the nature, specificity and the relevance of these changes at a molecular level are largely unknown and have been explored only sparsely. The result of non-enzymatic glycosylation i.e. glycation, is the formation of sugar- mediated crosslinks within the native structure of type I collagen. The chemistry behind these crosslinks, also known as Advanced Glycation Endproducts (AGEs), has been known for decades. However, the exact locations or regions of high propensity for the formation of these crosslinks within the packing structure of collagen are largely unknown. The results presented in this thesis inform on the location of possible crosslinks using the principle of Multiple Isomorphic Replacement (MIR) to and correlate the effects of crosslinks to the structural and functional sites present on the D-periodic arrangement of collagen into fibrils. An extension to this is the study of the effects of povidone-iodine on the packing structure of collagen. Iodine is used as a common disinfectant in surgery and first aid. Prolonged treatment with iodine is detrimental to the structure of collagen underlying the wound site (surgical or otherwise). This is particularly important in large surface area wounds, as seen in open-heart, hip and joint replacement surgeries and amputations. Diabetic patients are more prone to injuries to limb extremities and a common procedure to stop infections from spreading to the rest of the body is amputation of the limb and constant treatment with low doses of iodine immediately following surgery for a certain length of time. The results presented in this thesis demonstrate specific disintegration of collagen fibrils in rat tail tendons, from a short iodine treatment. This is detrimental for cellular activity, more so in processes like wound healing. TBI results in the loss of neurological control and/or function of various parts of the body, governed by this region. The results presented herein, inform and support the finding that neuroplasticity, in the hemisphere opposite to that where injury was delivered, compensates for the functional deficits as a result of TBI. The data presented here can be used in developing rehabilitation regimens for TBI patients on case-to-case basis to restore most of the functional deficits observed thereof, and also as a factor of predicting the onset of secondary neurological disorders (for instance amyloid related pathologies) at a later stage in life.
Ph.D. in Biology, December 2015
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Title: Thermoelectric Power Systems and the Energy-Water Nexus
Creator: Walker, Michael Edward
Date: 2012-04-26, 2012-05
Description: The goal of this Thesis is the development of a comprehensive methodology to evaluate the total cost of water use in the recirculating cooling...
Show moreThe goal of this Thesis is the development of a comprehensive methodology to evaluate the total cost of water use in the recirculating cooling loops of thermoelectric power plants. This methodology expands upon the work presented in the literature to improve estimations of the economic impact of condenser fouling. The methods developed in this Thesis are incorporated into a user friendly Combined Cost Model (CCM) interface that will allow future researchers, students and plant personnel to perform the same comparative analyses presented herein. The objective of this Thesis is the application of the CCM to determine the economic viability of treated municipal wastewater (MWW) use to replace freshwater for cooling in power plants with recirculating cooling systems. To accomplish this objective, a set of case study evaluations are included to (1) evaluate the sensitivity of the economic impact of fouling to condenser design and operation, (2) determine the cost of treated MWW use in pulverized coal power plants, and (3) compare the relative cost of degraded water use in advanced power systems such as IGCC and oxy-combustion. The results of these evaluations show that current freshwater prices do not provide an economic incentive to switch to the use of treated MWW water. However, results indicate that the breakeven differential price of freshwater, at which the total costs of using freshwater and treated MWW are equal, is only 0.52 $/1000Gal. (USD 2009). In addition, the use of treated MWW for cooling is shown to be a better economic alternative to dry air cooling technology (DACT) for the conservation of freshwater resources. Cost-to-conservation estimates of treated MWW use are 1.1 $/1000 Gal., in contrast to 5.6 $/1000 Gal. for DACT. This Thesis also presents a novel, hybrid coal conversion concept, the dry gasification oxy-combustion (DGOC) power cycle. This process is similar to oxycombustion, in that it maintains a concentrated CO2 flue stream and does not utilize a complex separation step. However, coal conversion and sulfur removal are performed within a gasification unit. It is estimated to achieve CCS goals with a higher efficiency than the leading alternative strategies.
Ph.D. in Chemical Engineering, May 2012
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Title: METHODOLOGY FOR VEHICLE EMISSION IMPACTS ANALYSIS FROM SIGNAL TIMING OPTIMIZATION OF AN URBAN STREET NETWORK
Creator: Lu, Pu
Date: 2017, 2017-05
Description: The pace of urban street capacity expansion is much slower than the growth of vehicle travel, leading to several traffic congestions. To...
Show moreThe pace of urban street capacity expansion is much slower than the growth of vehicle travel, leading to several traffic congestions. To mitigate traffic congestion expanding capacity is not feasible for many cases due to the high cost and space restriction. Improving the efficient use of the available capacity becomes the solution. Traffic signal optimization is one of the most widely used ways of efficient capacity utilization. Concurrent to traffic signal optimization, more smooth traffic operations in term of reasonably higher speed and a reduced traffic delay will in turn change vehicle emissions. This research aims to quantify changes in vehicle emissions resulted from traffic signal optimization by introducing a new methodology for quantifying network wide vehicle emissions and real world application in of the Chicago urban network for validation. The proposed methodology considers undersaturation and oversaturation of traffic conditions and urban street segments with varying speeds for different types of vehicles and pollutants by hour of the day and location within the network. It begins with information collection and research through a review of existing methods for urban street network vehicle emission estimation, intersection vehicle emission evaluation, and the running vehicle emission modeling. The proposed methodology focuses on three elements: estimation of emissions from vehicles stopped at intersections and for vehicles cruising along segments, as well as analysis of network wide vehicle emissions and changes in overall network vehicle emissions by time of the day and by areas. Major steps of methodology application included the use of Chicago TRANSIMS model implementing optimized signal timing plans to obtain refined traffic volumes at intersections and on segments, increased vehicle operating speeds, changed green splits, and vehicle compositions for all intersections and segments in the urban street network, the application of an intersection vehicle emission model for stopped vehicles and a segment vehicle emission model for vehicles cruising on segments, and the network wide analysis of vehicle emission changes by vehicle type and pollutant type in a 24-hour period within an urban street network, respectively. The proposed methodology for intersection vehicle emission estimation was successfully applied to a dense urban street network in Chicago for each approach per cycle and then extended for intersections in hours of the day to analyze the impacts of traffic changes at intersections on exhaust changes. In order to develop the network vehicle emission analysis method, it is essential to evaluate the segment vehicle emissions. This is achieved by using the concept of vehicle specific power which is used to estimate emissions of cruising vehicles considered along with vehicle speeds and speed changes and hence analyzing changes in segment vehicle emissions affected by traffic volume changes derived from signal timing optimization. The decreased number of vehicles stopped at intersections by applying signal timing optimization will reduce intersection emissions, hence reducing overall network vehicle emissions. In addition to have vehicle emissions got reduced at intersections, the increasing vehicle speed for vehicles on segments could further reduce vehicle emissions on segments.
Ph.D. in Civil Engineering, May 2017
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Title: TOWARD THE DEVELOPMENT OF USABILITY GUIDELINES FOR SINGLE-WINDOW WEB INTERFACES
Creator: Maciukenas, James
Date: 2013, 2013-05
Description: Since the early 1990s, usability research has guided development of web interfaces used to interact with content available on the Internet....
Show moreSince the early 1990s, usability research has guided development of web interfaces used to interact with content available on the Internet. Following these guidelines has resulted in web pages that in many characteristics are quite similar and are identified here as Conventional Web Interfaces (CWIs). An emergent genre of web interface, the Single Window Interface (SWI), differs in many ways from CWIs. Most importantly, SWIs differ from CWIs in the type of tasks expected of their users and in the visual strategies used to facilitate these tasks. Namely, SWIs facilitate open-ended discovery tasks by using strong visual cues to convey meta-information to the user and encourage both the exploration and perusal of content. This dissertation will demonstrate that the differences between SWIs and CWIs require revisiting current usability guidelines in order to determine how to guide future development of SWIs. If SWI visual strategies can be shown to be effective in conveying meta-information qualities to users, the groundwork will be prepared for future research investigating the effectiveness of these strategies in facilitating open-ended exploration and discovery within SWIs. These efforts will lead to more useful experiences for users of SWIs and inform the fields of technical communication as well as human-computer interaction and usability research, to name just a few of the affected fields of study.
PH.D in Technical Communication, May 2013
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Title: THE RELATIONSHIP BETWEEN ENACTMENT OF COMMON CORE STATE STANDARDS-MATHEMATICS, STUDENT MISCONCEPTIONS CONCERNING NEGATIVE SIGNS, DISTRIBUTION, AND DIAGRAMS, STUDENT ACHIEVEMENT, AND TEACHER VARIABLES
Creator: Morrissey, Glenda
Date: 2017, 2017-07
Description: The relationship between enactment of Common Core State Standards – Mathematics (CCSSM), student misconceptions, student achievement and...
Show moreThe relationship between enactment of Common Core State Standards – Mathematics (CCSSM), student misconceptions, student achievement and teacher variables was investigated. After providing professional development on CCSSM enactment, observations were conducted to determine the degree of enactment of CCSSM content and Standards for Mathematical Practice (SMP) in 22 classrooms of nine teachers in an urban charter school network consisting of three high schools. Students were all boys, 98% African American, and predominantly of low socio-economic status. Data included quarterly assessments, Partnership for Assessment of Readiness for College and Careers (PARCC) test scores, and a teacher survey. Results indicated experienced teachers with high efficacy who expected students to discuss their work were related to higher levels of CCSSM enactment in teacher actions, fewer misconceptions and higher test scores. Newer teachers were most concerned about availability of CCSSM materials and had higher levels of enactment of CCSSM in classroom materials. A strong belief in student ability was related to student enactment of SMP. Implications for teacher education, teacher practice, and future research are discussed.
Ph.D. in Mathematics and Science Education, July 2017
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Title: TRACING TEXTUAL MEDIATING ARTIFACTS AS AGENTS OF CHANGE AND VANGUARDS OF CORPORATE NORMS
Creator: Pappas, George
Date: 2017, 2017-05
Description: Technical communicators often employ user-centered design approaches to design textual artifacts that mediate workplace activity. The artifact...
Show moreTechnical communicators often employ user-centered design approaches to design textual artifacts that mediate workplace activity. The artifact’s designer is positioned as an expert who knows what is best for the artifact’s user (worker). I argue that those methods discount the role of the worker. I apply activity theory as the conceptual framework and genre tracing as the research method to analyze a corpus of documents that mediated the training evaluation activity at ABC Pharmaceutical (a pseudonym for the company’s name) to explain the evolution of those artifacts and theorize the reasons for their historical development. My findings show that their evolution – whether in the form of new genre selections, modifications, splicing, or even abandonment of genres – was influenced by worker efforts that challenged the official expert solutions. The implications of these findings to the fields of technical communication and business research are that even though design experts and business leaders may want to control the organizational strategies, work processes, and mediating artifacts/tools that accomplish those actions, workers will challenge official positions. There are dialectical forces at work that reflect official centripetal efforts that seek organizational stability from formal, normal, and regular structures versus centrifugal efforts that are disruptive and ad hoc in nature. The genre battles Idiscuss in this dissertation reflect a process that should be accepted as healthy and normal by both leadership and design experts, rather than feared or overly regulated.
Ph.D. in Technical Communication, May 2017
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Title: Architectural Considerations for Lunar Long Duration Habitat
Creator: Bahrami, Payam
Date: 2011-07, 2011-07
Description: The future of space exploration science and technology is expected to move toward long duration missions. During this long duration missions...
Show moreThe future of space exploration science and technology is expected to move toward long duration missions. During this long duration missions the most important factor to success will be the habitation system, the place that crew will live and work. The broad range of future space exploration, new advances in technology and increasing demand for space travel and space tourism will create great opportunities for architects to use their special abilities and skills in the realm of space. The lunar habitat is defined as a multidisciplinary task and cannot be considered an independent project from the main module. Therefore, habitability will become the most important aspect of future human exploration. A successful design strategy should integrate architecture, structure and other disciplines and should bring in elements such as psychological and physiological factors, human interfaces, and privacy. The current research provides “Habitat Architectural Design System (HADS)” in order to evaluate lunar habitat concepts based on habitability, functional optimization, and human factors. HADS helps to promote parametric studied and evaluation of habitat concepts. It will provide a guideline dependent upon mission objectives to standardize architectural needs within the engineering applications and scientific demands. The significance of this research is the process of developing lunar habitat concepts using an architectural system to evaluate the quality of each concept via habitability aspects. This process can be employed during the early stage of design development and is flexible enough to be adjusted by different parameters according to the objectives of lunar mission, limitations, and cost. It also emphasizes the importance of architecture involvement in space projects, especially habitats.
Ph.D. in Architecture, July 2011
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Title: DESIGN AND ANALYSIS OF AN UNCONVENTIONAL PERMANENT MAGNET LINEAR MACHINE FOR ENERGY HARVESTING
Creator: Zeng, Peng
Date: 2011-11, 2011-12
Description: The rise of global energy consumption and the growing trend to utilize clean energy stress the demand to harvest the untapped green energy...
Show moreThe rise of global energy consumption and the growing trend to utilize clean energy stress the demand to harvest the untapped green energy existing in every day life of human kind. Among the commonly over-looked energy resources, the kinetic motions including the vibration generated by linear motion and the vibration existent in ambient environment prove to own strong energy potentials. Though so far a number of such kinetic energy harvesters have already been studied, these existent energy harvesting devices can be improved on multiple aspects from power density, usage efficiency of expensive permanent magnetic material, to optimization of interface power electronics. This Ph.D. dissertation proposes an unconventional high power density linear electromagnetic kinetic energy harvester, and a high-performance two-stage interface power electronics to maintain maximum power abstraction from the energy source and charge the Li-ion battery load with constant current of low ripple at the same time. The proposed machine architecture is composed of a double-sided flat type silicon steel stator with winding slots, a permanent magnet mover, coil windings, a linear motion guide and an adjustable spring bearing. The unconventional design of the machine is that NdFeB magnet bars in the mover are placed with magnetic fields in horizontal direction instead of vertical direction and the same magnetic poles are facing each other. The derived magnetic equivalent circuit model proves the average air-gap flux density of the novel topology is as high as 0.73 T with 17.7% improvement over that of the conventional topology at the given geometric dimensions of the proof-of-concept machine. Subsequently, the improved output voltage and power are achieved. The dynamic model of the linear generator is also developed, and the analytical equations of output maximum xv power are derived for the case of driving vibration with amplitude that is equal, smaller and larger than the relative displacement between the mover and the stator of the machine respectively. Furthermore, the finite element analysis (FEA) model has been built and simulated to prove the derived analytical results and the improved power generation capability. Also, an optimization framework is explored to extend the dynamic system modeling method of the proposed single-Degree-of-Freedom (1-DOF) linear generator to the multi-Degree-of-Freedom (n-DOF) vibration based linear energy harvesting devices with multi proof masses and springs. Moreover, a boost-buck cascaded switch mode converter with current controller is designed to extract the maximum power from the harvester and charge the Li-ion battery with trickle current. Meanwhile, a maximum power point tracking (MPPT) algorithm is proposed and optimized for low frequency driving vibrations. Finally, a proof-of-concept unconventional PM linear generator is prototyped and tested to verify the simulation results of the FEA model. For the coil windings of 33, 66 and 165 turns, the output power of the machine is tested to have the output power of 65.6 mW, 189.1 mW, and 497.7 mW respectively with the maximum power density of 2.486 mW/cm3.
Ph.D. in Electrical Engineering, December 2011
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Title: ANISOTROPIC MICROSRHEOLOGY OF SELF-ASSEMBLING COLLAGEN NETWORKS
Creator: Dutov, Pavel
Date: 2015, 2015-05
Description: Collagen is the main component of human connective tissue and extracellular matrix. Here we report multiple novel methods for utilizing...
Show moreCollagen is the main component of human connective tissue and extracellular matrix. Here we report multiple novel methods for utilizing optical tweezers to measure mechanical properties of different hierarchical levels of collagenous materials. First, we introduce a method for optical trap calibration that is suitable for viscoelastic material. The method is designed for use on experimental setups with two optical tweezers and is based on pulling a trapped particle with one trap while holding it with the other. The method combines advantages of commonly known PSD-fitting and fast-sweeping methods, allowing calibration of a completely fixed trap in a fluid of unknown viscosity/viscoelasticity without additional expensive equipment. Then we report an approach to measure the longitudinal component of the elastic moduli of biological fibers under conditions close to those found in vivo and apply it to type I collagen from rat tail tendon. This approach combines optical tweezers, atomic force microscopy, and exploits Euler-Bernoulli elasticity theory for data analysis. The approach also avoids the traditional drying-soaking cycle, since samples are freshly extracted. Importantly, strains are kept below 0.5%, which appear consistent with the linear elastic regime. We find, surprisingly, that the longitudinal elastic modulus of type I collagen cannot be represented by a single quantity but rather is a distribution that is broader than the uncertainty of our experimental technique. Lastly, we report a new method for characterizing anisotropic viscoelastic response of collagenous matrices. Anisotropic collagenous extracellular matrices are used in biomedicine to enhance the wound healing process by directing fibroblast proliferation. We utilize an optical trap to monitor the thermal fluctuations of microspheres embedded into collagenous network to extract a viscoelastic response function of the network along the principal axes of anisotropy.
Ph.D. in Chemical Engineering, May 2015
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Title: TOWARD THE AUTOMATIC ORGANIZATION AND COMPREHENSION OF SOCIAL NETWORK COMMUNICATION
Creator: Platt, Alana
Date: 2013, 2013-05
Description: Social networking sites are radically transforming the way we communicate and relate to each other. They facilitate timely information...
Show moreSocial networking sites are radically transforming the way we communicate and relate to each other. They facilitate timely information exchange and give us unprecedented access to numerous sources of information on a myriad of topics. Although the information is available, there are a number of challenges that inhibit utilization of this information: Social Networks have a great volume of messages that the user must sift through to find relevant ones, messages are frequently repetitive, the information is not organized topically, and there is little context information. The information consumer (user) must take on many of the tasks traditionally performed by the information producer to get a “big picture” understanding of the topic. This thesis introduces a framework for an automated information gathering and organization system to facilitate the information consumer’s comprehension of a given topic. The framework addresses two primary components: the user interface for the system and identification of sub-topics. The framework was implemented as a research platform designed to bring these two components together and support future research in the domain.
PH.D in Computer Science, May 2013
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Title: Structural Survey of Select Spectrin Type Repeats within the Rod Region of Dystrophin Using Hydrophobic Moment Analysis and Molecular Dynamics Supplementing Crystallographic Data
Creator: Reinfelds, Pauls Edvins
Date: 2012-07-18, 2012-07
Description: Dystrophin is a rod shaped protein consisting of amino- and carboxy-terminal binding domains linked by a large central rod composed of 24...
Show moreDystrophin is a rod shaped protein consisting of amino- and carboxy-terminal binding domains linked by a large central rod composed of 24 homologous copies of the STR motif and 5 non-homologous regions termed hinges. There are no high-resolution crystallographic structures available for the STR repeats. This work yielded protein crystals and data sets of two STR fragments (d5 & d16-17). Though unable to produce a high resolution structure, this work examines the physical properties of the rod region utilizing hydrophobic moment analysis and molecular dynamics to suggest flexibility among the helices of the STR fragments. Helical shifting appears to possibly occur among the more stable STR tandems to increase the cooperation among certain adjacent fragments. A full understanding of how these properties vary along the length of the rod has implications for the engineering of these rods regions in future dystrophin therapies.
Ph.D. in Biology, July 2012
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