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Title: The Impact of Professional Devlopment in Informal Science Contexts on Teachers' Content Knowledge and Discourse
Creator: Holliday, Gary
Date: 2011-07, 2011-07
Description: Little in the research has addressed how professional development at an Informal Science Institution (ISI) might influence teachers’ learning...
Show moreLittle in the research has addressed how professional development at an Informal Science Institution (ISI) might influence teachers’ learning of science content or how exhibits and exhibit-related instructional approaches used during such courses contribute to this learning. It has also been noted that informal science professional development programs are often underutilized (Phillips, Finkelstein, & Wever-Frerichs, 2007) and it has been suggested that this may be due to ISIs not fulfilling teachers’ science content needs. The Contextual Model of Learning (CML; Falk & Dierking, 1992, 2000) and reform documents have emphasized the unique learning environments that ISIs provide and the social aspects of that learning. As a result, individuals are able to use “each other as vehicles for reinforcing beliefs and meaning making” (Kisiel, 2003, p. 3). This study looked at two science content courses that were taught over two years by education staff of a large science and technology museum located in the Midwest. Data from six courses, with 187 participating elementary and middle school teachers, included content tests, portfolios and graduate credit assignments, daily and final evaluations of the course, as well as audio and video recordings of teachers while they were interacting with exhibits or engaged in an exhibit related activity. Results of this study found that PD educators’ use of exhibits during both courses did not fully take into account the sociocultural context of CML and did not actively incorporate opportunities for discourse into the course instruction. However, when PD staff did make explicit connections between exhibits, science content, and activities, xi participants were more likely to be involved in in-depth, content related and pedagogical conversations while engaged in the courses. At the same time, even though teachers were very satisfied with the courses and felt that PD staff was effective in their instruction, participating teachers did not increase their science content knowledge even when explicit content connections were made to exhibits. It was unclear what outcomes the PD educators expect or want for their teacher students other than relaying content in a didactic manner (which was a secondary concern), sparking an interest in science, and providing many hands-on activities to bring back to the classroom. There is a need for a standardized professional development program for ISI educators and a need for restructuring ISI professional development so that it will address elementary and middle school teachers’ need for science content. Further, developing instructional strategies for informal sites will be important since the learning potential that can be found through exhibits and exhibitions are not being fully realized.
Ph.D. in Science Education, July 2011
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Title: MULTIPHASE CFD MODELING AND SIMULATION OF GAS-SOLID FLOW SYSTEMS INCLUDING CO2 CAPTURE PROCESSES
Creator: Ghadirian Hoseinabadi, Emad
Date: 2016, 2016-05
Description: Carbon capture and sequestration (CCS) is one of the key technologies needed to reduce the carbon dioxide (CO2) emission and its effects on...
Show moreCarbon capture and sequestration (CCS) is one of the key technologies needed to reduce the carbon dioxide (CO2) emission and its effects on climate change. The goal of this study is to develop an advanced design and scale-up tool for a regenerable solid sorbent carbon capture process using computational fluid dynamics (CFD). In this study, a systematic methodology was established, starting from investigating the properties of the sorbent and its reaction kinetics, to developing models to design, evaluate, troubleshoot, and scale-up of the reactors that are needed to deploy this technology for an advanced power plant (i.e., integrated gasification combined cycles [IGCC]). To develop a realistic CFD model, the effect of formation of clusters in the system was studied using an energy minimization multi-scale (EMMS) approach and was shown to calculate the fluidized bed expansion with high accuracy. The effect of compaction of particles was also investigated and a model capable of simulating independent experimental data for the angle of repose was presented. In addition, this dissertation provides detailed investigations of a magnesium oxide (MgO)-based sorbent and its performance for CO2 capture from a syngas stream including the development of shrinking core models (SCM). Initially, the regenerator fluidized bed reactor at elevated temperature and pressure was simulated and several case studies were performed. Furthermore, a three-dimensional (3D) CFD simulation of a full-loop circulating fluidized bed was provided based on the developed constitutive relations and coupling them with two-fluid model equations. In order to reduce the computational time, a CFD simulation in a two-dimensional (2D) domain including heterogeneous regeneration and carbonation reactions based on the shrinking core model was performed that can be used for parametric studies and optimization of the CO2 sorption and desorption processes in a circulating fluidized bed (CFB) reactor. In addition, a coupled CFD-PBE (population balance equation) model based on the FCMOM (finite size domain complete set of trial functions method of moments) approach was developed and was shown to have broad application in reaction engineering and reactor design where the poly-disperse nature of the phases has a strong effect on the hydrodynamics of the system such as coal gasifiers. Finally, the base case design for CFB reactors incorporated in the CO2 capture process using techno-economic analysis was developed and the operating and capital costs of the unit were demonstrated. It was shown that capturing CO2 in an IGCC power plant by pre-combustion technology is economically viable and can compete with other available technologies.
Ph.D. in Chemical Engineering, May 2016
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Title: POWER GRID OPERATION RISK MANAGEMENT: V2G DEPLOYMENT FOR SUSTAINABLE DEVELOPMENT
Creator: Haddadian, Ghazale J.
Date: 2014, 2014-05
Description: The production, transmission, and delivery of cost–efficient energy to supply ever-increasing peak loads/demands along with a quest for...
Show moreThe production, transmission, and delivery of cost–efficient energy to supply ever-increasing peak loads/demands along with a quest for developing a low-carbon economy require significant evolutions in the power grid operations. Lower prices of vast natural gas resources in the United States, Fukushima nuclear disaster, higher and more intense energy consumptions in China and India, issues related to energy security, and recent Middle East conflicts, have urged decisions makers throughout the world to look into other means of generating electricity locally. As the world look to combat climate changes, a shift from carbon-based fuels to non-carbon based fuels is inevitable. It is possible to knock a lot of carbon out of the electric power system through large-scale integrations of renewable sources. However, the variability of distributed generation assets (such as wind and solar) in the electricity grid has introduced major reliability challenges/risks for power grid operators. While spearheading sustainable and reliable power grid operations, this dissertation develops a multi-stakeholder approach to power grid operation design; aiming to address economic, security, and environmental challenges of the constrained electricity generation. It investigates the role of Electric Vehicle (EV) fleets integration, as distributed and mobile storage assets to support high penetrations of variable and renewable energy sources, in the power grid. The vehicle-to-grid (V2G) concept is considered to demonstrate the bidirectional role of EV fleets both as a provider and consumer of energy in securing a sustainable power grid operation. The V2G concept is regarded as a novel, low-cost, low-emission and sustainable strategy that can address xv challenges involve with using renewable energy sources, which require means of storing large quantities of energy. The proposed optimization modeling is the application of Mixed-Integer Linear Programing (MILP) to large-scale systems to solve the hourly security-constrained unit commitment (SCUC) – an optimal scheduling concept in the economic operation of electric power systems. The Monte Carlo scenario-based approach is utilized to evaluate different scenarios concerning the uncertainties in the operation of power grid system. Further, in order to expedite the real-time solution of the proposed approach for large-scale power systems, this dissertation considers a two-stage model using the Benders Decomposition (BD) and applies the BD method to the hourly SCUC solution of electric power systems with significant uncertainties. The numerical simulation demonstrate that the utilization of smart EV fleets in power grid systems would ensure a sustainable grid operation with lower carbon footprints, smoother integration of renewable sources, higher security, and lower power grid operation costs. Further, simulation results indicate that intelligent-controlled mode, in which electric power system operators control the EV fleets charge/discharge decisions based on the system operation requirements, is more effective compare to the rule-based mode, in which consumers control charging/discharging decisions. The numerical simulations, additionally, illustrate the effectiveness of the proposed MILP approach and its potentials as an optimization tool for sustainable operation of large scale electric power systems.
PH.D in Management Science, May 2014
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Title: RISK FACTORS ASSOCIATED WITH POSTPARTUM DEPRESSION: A FOCUS ON PERINATAL ANXIETY
Creator: Getch, Sarah
Date: 2011-12, 2011-12
Description: Our objective was to expand previous research examining the course of anxiety and the comorbidity of anxiety and depression during pregnancy...
Show moreOur objective was to expand previous research examining the course of anxiety and the comorbidity of anxiety and depression during pregnancy and postpartum. The sample comprised 80 pregnant female participants varying in age, ethnicity, and primary diagnosis recruited through the Division of General Obstetrics and Gynecology at NMFF and PAC during routine obstetric visits or by advertisements placed on the internet via the website Craigslist. Clinical data were collected once during the second or third trimester of pregnancy and once at 6 weeks postpartum. Participants were asked to complete the Edinburgh Postpartum Depression Scale (EPDS), the Quick Inventory of Depressive Symptoms (QIDS), the Positive and Negative Affect Scale (PANAS), the Patient Health Questionnaire – 9 (PHQ-9), the State Trait Anxiety Inventory (STAI), the Penn State Worry Questionnaire (PSWQ), the Zung Self-report Anxiety Scale (SAS), the Social Support Questionnaire - Short Form (SSQ-SF), and the Perceived Stress Scale (PSS). Results indicated that prenatal anxiety partially mediated the relationship between prenatal depression and postpartum depression. Additionally, prenatal anxiety fully mediated the relationship between prenatal social support and postpartum depression as well as the relationship between prenatal stress and postpartum depression.
Ph.D. in Psychology, December 2011
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Title: Conceptual Model of Design Creativity: Fostering Creative Cognition in Architecture and Design Pedagogy
Creator: Fakhra, Ahmad Jasem
Date: 2012-12-02, 2012-12
Description: Creativity in architecture and design disciplines is highly commended, considered essential in design processes, and regarded as invaluable to...
Show moreCreativity in architecture and design disciplines is highly commended, considered essential in design processes, and regarded as invaluable to the prosperity and survival of design organizations. Creativity is also considered a vital learning outcome in architecture and design pedagogy. Many teachers strive to cultivate creativity in their students and consider it as essential for shaping successful architects and designers. This research proposes a Conceptual Model of Design Creativity based on a synthesis of knowledge from architecture and design pedagogy and creative practice, and understandings of creativity from cognitive psychology and neurocognitive science. The purpose of the proposed model is to articulate the constituents necessary for conceptualizing design creativity and creative design processes. The model also provides the means for understanding how creativity emerges and what is involved in fostering creative cognition in the context of design pedagogy for architecture and other design disciplines. The research also proposes a Design Creativity Cards tool. The purpose of the tool is to help design students stimulate cognitive mechanisms and styles commonly associated with the production of creative results. This research adopts a mixed-methods qualitative research approach for a crossdisciplinary synthesis of creativity research between the literature on creativity from cognitive psychology and neurocognitive science and the literature on architecture and design pedagogy and practice. The development of the Conceptual Model of Design Creativity was informed by an extensive and critically framed literature review. The model was also informed by insights from Grounded Theory analysis of published interviews and reflective writings of twenty eminent creative individuals and xi organizations that identified influential elements of creativity in art, architecture, and design creative practice. The Conceptual Model of Design Creativity informed the development of the Design Creativity Cards tool deployed in the empirical research. The cards were informed by creativity methods from cognitive psychology. The research employed both the tool and the model to frame the development of a design experimental study and the data analysis and findings. The purpose of the design experimental study is to investigate the role of the Design Creativity Cards in stimulating creative cognition. The experiment was conducted with thirty-one undergraduate and master-graduate students from three architecture and design schools. Participants from each school were divided into control and experimental groups and were engaged in a simple design task. The experimental groups were introduced to the Design Creativity Cards in a preliminary workshop and were then asked to use the cards during the design task. The data collected were analyzed in relation to seven divergent thinking abilities; the seventh ability of “ideation leap” emerged through analysis as a contribution from and of this research. The data were also analyzed in relation to the Conceptual Model of Design Creativity. The findings provide a proof of concept for the Conceptual Model of Design Creativity and the Design Creativity Cards tool that suggests support for their role in enhancing creative cognition.
PH.D in Design, December 2012
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Title: Completing the Puzzle: Comparable Community Determination for Illinois Municipalities
Creator: Ahrens, Aric G.
Date: 2012-07-16, 1998-05
Description: In the process of negotiating for new contracts, public safety (i.e. Police and Firefighters) employee unions and municipal managers compare...
Show moreIn the process of negotiating for new contracts, public safety (i.e. Police and Firefighters) employee unions and municipal managers compare the essential elements of their contract (i.e. wages) with those of other “comparable” municipalities. The wages, benefits and working conditions of other “comparable” municipalities are used to provide evidence supporting the positions taken on both sides of the negotiating table. The problem is that negotiating teams rarely employ a consistent and accurate method to determine which municipalities should be compared to their own. Negotiating teams make their own determinations of comparability, which must be defended should arbitration proceedings become necessary. However, most of the methods of comparability determination currently employed by negotiating teams are extremely simple and are lacking a sound analytical basis. These methods are inadequate in terms of accuracy, and would be difficult to defend in arbitration proceedings. The method outlined in the following report provides a sound analytical basis for comparability determination. The recommendation is to employ the use of Comparability Tables. Comparability Tables : The Tables provide a list of which communities are most comparable to each particular community, and how comparable they are. This solution is augmented by three supporting elements which help to address the weaknesses apparent in the Comparability Tables. The three supporting elements are a Dissimilarity Matrix, Factor Analytic Rankings, and Factor Analytic Tables. Dissimilarity Matrix : The Matrix provides a comparability determination for communities not listed on a particular community’s Comparability Table. Factor Analytic Rankings : The Rankings allow a determination of why two communities are or are not comparable. Factor Analytic Tables : The Tables allow a quick reference to the particular characteristics of each community. The Comparability Tables, along with the supporting elements, provide negotiating teams with a list of comparable communities that is more accurate and defensible than the lists provided by other methods. This method describes which communities are comparable, how comparable they are, and why they are comparable. Negotiating teams who employ this method of comparability determination can approach their negotiations confident that their choice of comparable communities is accurate and can stand up to an arbitrator’s inquiry.
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Title: BIOMATERIAL SYSTEMS WITH PERSISTENT GROWTH FACTOR GRADIENTS IN VIVO FOR TISSUE ENGINEERING APPLICATIONS
Creator: Akar, Banu
Date: 2016, 2016-12
Description: Tissue engineering aims to develop strategies for the replacement of damaged, injured or missing tissues with biologically compatible...
Show moreTissue engineering aims to develop strategies for the replacement of damaged, injured or missing tissues with biologically compatible substitutes such as bioengineered tissues. However, generating tissues of su cient volume for clinical application requires the formation of stable and extensive vasculature within the tissue constructs. The overall goal of this work is to enhance vascularization using a gradient biomaterial system and apply this research to engineering vascularized bone of clinical size. First, a method was developed to create persistent growth factor gradients with an adjustable gradient magnitude in vivo. This method generated persistent gradients of platelet-derived growth factor (PDGF-BB) within brin/poly (ethylene glycol) (PEG) sca olds. The presence of a growth factor gradient within the system was veri ed in vivo using near-infrared imaging. Also, a computational model was developed to investigate gradient characteristics within the system. Gradient properties can be controlled by varying the degradation rate of the gradient layer components or dose of PDGF-BB delivered. The angiogenic potential of gradient sca olds was tested in rodents using a subcutaneous implantation model. The depth of tissue invasion and density of blood vessels formed in response to the biomaterial increased with dose of the growth factor. The gradient biomaterial system allows formation of persistent gradients that can be in uenced by biomaterial characteristics, and enhances vascularization. Therefore, this biomaterial system can be used for tissue engineering applications. Second, the brin/PEG-based sca olds were modi ed to be degradable via hydrolysis and to include bioactive ceramic particles (hydroxyapatite and -tri-calcium phosphate). Characteristics of the hydrogel ceramic composites were investigated in vitro and in vivo. The presence of ceramic particles extended degradation time of thehydrogels in vitro and in vivo. Hydrogel ceramic composites were tested in a rodent cranial defect model and enhanced bone tissue regeneration. Third, strategies developed from the previous studies were combined to prepare ceramic supplemented gradient sca olds for bone tissue engineering applications. A gradient layer was applied to the hydrogel-ceramic composites and bone tissue response was evaluated in a periosteum guided large animal model. Ceramic supplemented gradient sca olds augmented vascularization and bone regeneration in vivo. In conclusion, a biomaterial system with persistent growth factor gradients was developed and enhanced vascularization and bone regeneration in vivo. This system holds a great potential for tissue engineering applications.
Ph.D. in Biomedical Engineering, December 2016
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Title: EVALUATION OF A MODIFIED ITEM PARAMETER REPLICATION METHOD FOR DIFFERENTIAL FUNCTIONING OF ITEMS AND TESTS ANALYSIS WITH UNEQUAL SAMPLE SIZES
Creator: Blitz, David L.
Date: 2016, 2016-05
Description: In 1995, Raju, van der Linden, and Fleer introduced the Differential Functioning of Items and Tests (DFIT) framework. However, some concerns...
Show moreIn 1995, Raju, van der Linden, and Fleer introduced the Differential Functioning of Items and Tests (DFIT) framework. However, some concerns have been raised regarding the accuracy of DFIT (e.g., Meade & Lautenschlager, 2004, 2005). More recently, it was suggested that large differences in sample sizes might affect the sampling variance of the NCDIF statistic (e.g., Raju et al., 2009). The purpose of this study was to confirm if differing subgroup sample sizes affect the accuracy of the NCDIF statistic and to propose and evaluate a modification to solve this problem. Monte Carlo results indicated that the old method generally maintained fairly stable power, but tended to be overly conservative when the focal group was smaller than the reference group and exhibit inflated Type I error when the focal group was larger than the reference group. The new method generally maintained reasonable Type I error regardless of subgroup sample size and demonstrated comparable or better power except for conditions where the old method exhibited inflated Type I error rates. When impact was present Type I error rates were slightly higher and power was slightly lower but results otherwise conformed to the general pattern.
Ph.D. in Psychology, May 2016
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Title: THE IMPACTS AND “BEST PRACTICES” OF UNDERGRADUATE – GRADUATE STUDENT MENTORING RELATIONSHIPS IN UNDERGRADUATE RESEARCH EXPERIENCES
Creator: Campanile, Megan Faurot
Date: 2015, 2015-12
Description: Undergraduate research has been identified as an educational practice in the U.S. that directly addresses issues with science education at...
Show moreUndergraduate research has been identified as an educational practice in the U.S. that directly addresses issues with science education at both the undergraduate and graduate school levels. With the growth of undergraduate research in the U.S., over the past two decades, faculty are more often assigning graduate students to mentor undergraduate students than providing the one-on-one mentoring themselves. A critical gap that exists in the literature is how the mentoring relationships in undergraduate research influence the academic and career outcomes of both the undergraduate and graduate students. The two main research questions that framed this study were: (1) What, if any, changes occur in the academic and career paths of undergraduate and graduate students who participate in undergraduate research experiences? and (2) Are there variables that constitute “best practices” in the mentoring relationships in undergraduate research experiences and, if so, what are they?. The context of this study was the National Science Foundation (NSF) Research Experiences for Undergraduates (REU) program at Illinois Institute of Technology (IIT) and the 113 undergraduate researchers and 31 graduate student mentors who participated from 2006 – 2014. In addition, there was a purposeful sample of six pairs selected to develop case studies and illustrate the complexities of the undergraduate – graduate student mentoring relationships. Data collection occurred in two phases: the first phase collected pre- and post-program data from the undergraduate researchers during the delivery of the 10-week REU program; and, the second phase collected follow-up data from both the undergraduate researchers and graduate student mentors during the 2014 – 2015 academic year. Surveys and semi-structured interviews were administered to ask the undergraduate researchers and graduate student mentors about their academic and career paths and mentoring relationship experiences and views. The data collected was analyzed using descriptive statistics, content analysis method, and constant comparative method. The key findings on the undergraduate researchers’ academic and career paths were their actual earned graduate degree types (Ph.D. 20%, M.D. 20%, M.S. 48%, other 12%) and fields (STEM 57%, medical 35%, and other 8%). In addition, the career fields (STEM 68%, medical 26%, and 6% other) and sectors (industry 43%, healthcare 30%, academia 17%, and other 10%) that the undergraduate researchers were pursuing or working in. This is the first known study to examine the career paths of graduate student mentors of REU programs and it found that they were all pursuing or working in STEM fields and, specifically, in the career sectors of academia (50%), industry (40%), and government (10%). More than 75% of both the undergraduate researchers and graduate student mentors paired together reported that their mentoring relationships in undergraduate research had a somewhat to extremely influential impact on their academic and career paths. To gain insight into how they influenced one another and to identify the “bestundergraduate researchers and graduate student mentors about their academic and career paths and mentoring relationship experiences and views. The data collected was analyzed using descriptive statistics, content analysis method, and constant comparative method. The key findings on the undergraduate researchers’ academic and career paths were their actual earned graduate degree types (Ph.D. 20%, M.D. 20%, M.S. 48%, other 12%) and fields (STEM 57%, medical 35%, and other 8%). In addition, the career fields (STEM 68%, medical 26%, and 6% other) and sectors (industry 43%, healthcare 30%, academia 17%, and other 10%) that the undergraduate researchers were pursuing or working in. This is the first known study to examine the career paths of graduate student mentors of REU programs and it found that they were all pursuing or working in STEM fields and, specifically, in the career sectors of academia (50%), industry (40%), and government (10%). More than 75% of both the undergraduate researchers and graduate student mentors paired together reported that their mentoring relationships in undergraduate research had a somewhat to extremely influential impact on their academic and career paths. To gain insight into how they influenced one another and to identify the “best practices” of mentoring, the results on the mentoring experiences and views were triangulated which included a systematic compare and contrast of the six case studies. A set of “best practices” were developed for both the undergraduate researchers and graduate student mentors and they focused on the positive and challenging experiences they can expect in a mentoring relationship related to learning and teaching about research; relationship dynamics and roles; and, planning, practicing, and preparing for the future. The findings on the academic and career paths and “best practices” have the potential to maximize and improve undergraduate research experiences for bothpractices” of mentoring, the results on the mentoring experiences and views were triangulated which included a systematic compare and contrast of the six case studies. A set of “best practices” were developed for both the undergraduate researchers and graduate student mentors and they focused on the positive and challenging experiences they can expect in a mentoring relationship related to learning and teaching about research; relationship dynamics and roles; and, planning, practicing, and preparing for the future. The findings on the academic and career paths and “best practices” have the potential to maximize and improve undergraduate research experiences for bothpractices” of mentoring, the results on the mentoring experiences and views were triangulated which included a systematic compare and contrast of the six case studies. A set of “best practices” were developed for both the undergraduate researchers and graduate student mentors and they focused on the positive and challenging experiences they can expect in a mentoring relationship related to learning and teaching about research; relationship dynamics and roles; and, planning, practicing, and preparing for the future. The findings on the academic and career paths and “best practices” have the potential to maximize and improve undergraduate research experiences for both undergraduate and graduate students. More policymakers, research universities, and faculty may be willing to invest, both financially and operationally, in undergraduate research knowing that it benefits not only undergraduate students but graduate students’ academic and career paths. The “best practices” have the potential to make an impact once they are incorporated into mentor training programs that are delivered in conjunction with undergraduate research programs. Future studies recommended are longer duration longitudinal studies as well as comparative studies of undergraduate research program with and without mentor training programs. In addition, the future studies need to include larger and more diverse samples to increase the generalizability of the findings. Ultimately, by improving the mentoring relationships in undergraduate research it has the potential to improve both undergraduate and graduate education and produce more highly qualified scientists and engineers for the U.S. workforce.
Ph.D. in Science Education
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Title: THERMAL AND MECHANICAL ANALYSIS OF ELECTRON BEAM ADDITIVE MANUFACTURED TI-6AL-4V BUILD PLATE
Creator: Cao, Jun
Date: 2017, 2017-07
Description: Electron Beam Additive Manufacturing (EBAM), used to fabricate net or nearnet- shaped components based on a sliced CAD model, offers a...
Show moreElectron Beam Additive Manufacturing (EBAM), used to fabricate net or nearnet- shaped components based on a sliced CAD model, offers a potential alternative solution for the processing of titanium components, especially for large parts. However, the components fabricated using EBAM exhibit significant difficulties in quality control and quality assurance due to lack of knowledge of thermo-mechanical-metallurgical relationship. In this work, the thermo-mechanical behavior of wire-feed EBAM for largescale Ti-6Al-4V build plates has been investigated computationally and experimentally, with special attention to the distortion and residual stress, as well as the microstructural evolution. A 3D transient fully coupled thermo-mechanical finite element (FE) model was built, calibrated, and rigorously validated. To ensure the accuracy of the model, the bulk residual strain distribution was measured using neutron diffraction (ND), and the numerically simulated thermal profiles were physically simulated using a Gleeble® 3500, in addition to the conventional model validation methods. Good agreement was found between the simulation results and experimental measurements. A series of simulations were performed to determine the optimum process conditions. The simulation results indicated that preheating, increasing deposition power and scan rate, and decreasing interval cooling time effectively mitigates the distortion and residual stress. For EBAM Ti-6Al-4V build plates, increasing the energy input and reducing the heat loss renders smaller temperature difference and thermal expansion mismatch, consequently, leading to a lower level of distortion and residual stress. The deposited cladding was characterized by large columnar grains growing across layers, a bottom region with repeated macroscopic bands and a top region without these bands. The band structure exhibits mostly colony α. A fine basket-weave structure is observed above the band structure, and a coarse basket-weave structure is observed below the band structure. The simulated thermal profiles were used to understand the observed microstructure. It was found that the microstructure variation in the cladding of EBAM Ti-6Al-4V build plates is strongly dependent on the peak temperature within the (α+β) phase region, and heating rate and cooling rate have insignificant effects on it. The non-equilibrium solid-solid phase transformation of Ti-6Al-4V under continuous heating/cooling were experimentally investigated. The kinetics of phase transformation was quantitively studied and modeled using a non-isothermal JMAK (Johnson-Mehl-Avrami-Kolmorgorov) model, with the activation energy QA=123.9 kJ/mole, JMAK exponent n=1.8, and the calculated ln (k0) varied between 9.15 to 10.6 for different heating rate.
Ph.D. in Materials Science and Engineering, July 2017
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Title: CARBON DIOXIDE CAPTURE USING SOLID SORBENTS IN A FLUIDIZED BED WITH REDUCED PRESSURE REGENERATION IN A DOWNER
Creator: Kongkitisupchai, Sunti
Date: 2012-11-11, 2012-12
Description: The most commonly used commercial technology for post-combustion CO2 capture for existing power plants is the amine solvent scrubber. However,...
Show moreThe most commonly used commercial technology for post-combustion CO2 capture for existing power plants is the amine solvent scrubber. However, the energy consumption for capturing CO2 from flue gases using amine solvent technology is 15 to 30% of the power plant due to the use of steam in solvent regeneration. Hence there is a need to develop more efficient methods of removing CO2. The objective of this thesis research is to demonstrate the design of a complete loop system of dry solid sorbent technology, which consumes less energy, as an alternative CO2 capturing technology. The design of a complete riser-sorber and downer-regenerator loop system for a dry solid sorbent technology is developed using the recently developed kinetic theory based multiphase computational fluid dynamics (CFD). The complete dry solid sorbent loop system comprises of an atmospheric fluidized bed riser-sorber and a reduced pressure downer-regenerator. The proposed dry solid sorbent used in this thesis research is a dry sodium carbonate sorbent recently developed at RTI and earlier by Gidaspow and Onischak. The dry solid sorbents capture CO2 and water vapor from flue gases through chemical sorption in the sorber-riser. The captured CO2 is released from the solid sorbent along with water vapor in the reduced pressure regenerator-downer where the solid sorbent regeneration occurred. The complete dry solid sorbent loop system demonstrates the possibility of solving three main technical challenges, which are the handling of large volumetric flow rate of the flue gases, the required operating power, and the quantity of CO2 sorption. xvii A new proposed pressure-equilibrium based sorption rate model for the dry sodium carbonate sorbents is used in the simulations. The simulations of both fluidized riser-sorber and downer-regenerator were done using commercial CFD code; Fluent. The energy efficiency of the proposed dry solid sorbent loop system was studied using thermodynamic availability analysis for both an individual vessel and for the overall process for evaluating the minimum energy requirement for CO2 separation. A T-s diagram of inlet and outlet streams for both the riser-sorber and the downer-regenerator are included in the thermodynamics analysis. The results from multiphase CFD simulations showed that the heat liberated during CO2 sorption in the riser-sorber can be nearly fully recovered in form of sensible heat in the solid sorbent. The captured heat in the solid sorbents is used as the energy for CO2 desorption in the sorbent regeneration process inside the reduced pressure downerregenerator. Hence, the only parasitic power loss will be the energy needed for sorbent circulation, air-lock rotary valves, and vacuum fan. The drastic energy saving is possible due to the high solid circulation rate between sorber-riser and downer-regenerator. Additionally, the simulation results showed that the core-annular regime flow pattern in the riser-sorber can be almost completely eliminated by using multiple jet inlets and increasing solid sorbent particle size, from 75 microns manufactured by RTI to 500 micron sorbent particles. Furthermore, the large sorbent particle size allows better solid settling in the downer. The simulations also showed that a core-annular flow pattern occurred inside the downer-regenerator. However, there is no negative effect of having a core-annular regime inside the downer-regenerator.
PH.D in Chemical Engineering, December 2012
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Title: BODY DISSATISFACTION, CORRELATES OF BODY IMAGE DISTURBANCE, AND PERCEPTIONS OF THE IDEAL FEMALE BODY SHAPE
Creator: Westercamp, Kindra L.
Date: 2012-07-16, 2012-07
Description: Body image concern is not a foreign experience among men; the literature indicates that men, like women, experience negative thoughts about...
Show moreBody image concern is not a foreign experience among men; the literature indicates that men, like women, experience negative thoughts about their body. It continues to be accepted that women experience greater body dissatisfaction than do men; however, based on prior research, this conclusion may be inaccurate. The primary aim of the present study was to examine whether the discrepancy between current body size and ideal body size differed by sex; the examination was conducted with the overall sample and then with only those men and women who preferred a slimmer physique. Self-esteem, internalization of the cultural-ideal, and body acceptance were examined in relation to weight concern, overall body dissatisfaction in women, muscularity dissatisfaction in men, and the body size discrepancy estimate. An additional purpose of the present study was the investigation of a potential consequence among women of misperceiving the body preferences of men. Also explored was whether the body size discrepancy, derived from a figural measure, is a valid measure of body dissatisfaction. Participants were 248 men and women college students who completed 10 self-report questionnaires and engaged in the Body Morph Assessment Program Version 2.0 (BMA 2.0), a computerized body image assessment procedure. Results indicated that the average body size discrepancy was greater for women in the overall sample; yet, in the restricted sample no sex difference was observed. In comparison to self-esteem and internalization of the cultural-ideal, body acceptance was found to be most consistently related to the aforementioned constructs. Also found was that the more slender a female figure women regarded as being most attractive to men the more they engaged in disordered eating. Results of the present study suggested that the discrepancy estimate likely measures a construct that is different than that measured by an evaluative measure of overall body dissatisfaction or weight concern.
Ph.D. in Psychology, July 2012
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Title: CHILD AND PARENT PSYCHOPATHOLOGY: COMBINATIONS RELATED TO THERAPY ATTENDANCE AND PROGRESS
Creator: Giannone, Carolyn D.
Date: 2012-04-30, 2012-05
Description: Disruptive behavior disorders (DBDs) are among the most common and challenging diagnoses in children. It is well documented that family...
Show moreDisruptive behavior disorders (DBDs) are among the most common and challenging diagnoses in children. It is well documented that family therapy services can provide effective treatment for DBDs, but therapy dropout rates are high. This leaves many children untreated, particularly in urban settings. Literature supports relationships between several variables and premature termination of therapy services, including child gender, child psychopathology, parent psychopathology, and perceived barriers to treatment participation. The current study aimed explore if combinations of parent and child psychopathology and their relationship related to therapy completion. Multiple imputation was utilized due to the presence of several missing data points. Results indicated that combinations did not significantly predict therapy completion. Implications of the research, limitations, and suggestions for future research are discussed.
Ph.D. in Clinical Psychology, May 2012
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Title: GRAIN BOUNDARY ENGINEERING OF POWDER-PROCESSED NI-BASE SUPERALLOY RR1000
Creator: Detrois, Martin
Date: 2016, 2016-05
Description: Grain boundary engineering (GBE) has been used to improve the properties of various polycrystalline materials by optimization of their grain...
Show moreGrain boundary engineering (GBE) has been used to improve the properties of various polycrystalline materials by optimization of their grain boundary network. Traditional processing routes for GBE often require multiple iterations of cold work followed by short annealing cycles where each iteration imparts a modest increase in the fraction of special grain boundaries. Multiple iterations are then required to achieve sufficiently high fractions (>50%) that result in the improved properties. Thus, this GBE approach is not suitable for the fabrication of large, complex-shaped structures and leads to added manufacturing lead time and cost. In this investigation, the Ni-base superalloy RR1000 used as turbine discs in gas turbine engines manufactured by Rolls-Royce, was considered for GBE using alternative processing routes more suitable to the forging of Ni-base superalloy components. A preliminary study of the e↵ects of hot deformation parameters closer to typical industrial processing revealed that the length fraction of ⌃3 boundaries increased from 35% to 52% following a single deformation/anneal cycle. Deformation parameters that resulted in strain accommodation via superplastic flow did not enhance the formation of ⌃3 boundaries upon annealing. Whereas deformation parameters that resulted in a dominant dislocation-based plasticity flow mechanism promoted the formation of annealing twins. Using misorientation maps and by estimating the stored strain energy from deformation, equations for the length fraction and density of ⌃3 boundaries were generated for high-temperature GBE of RR1000. The grain boundary characters obtained via high-temperature deformation, however, are less ideal than those resulting from traditional cold rolling. The underlying mechanisms responsible for the formation of ⌃3n boundaries during high-temperature GBE were further investigated. A larger starting grain size prior to deformation was found to be unfavorable to the formation of twin boundaries from twin-reorientation and annihilation of preexisting twins. While recrystallization was found to populate the microstructure with grains that contained very few twin boundaries, post-deformation texture was found to promote the formation of ⌃3 boundaries and triple junctions when Goss texture was present. A final consideration of larger scale forgings was used to raise an outlook on the current issues and the potential of high-temperature GBE for turbine engines.
Ph.D. in Materials Science and Engineering, May 2016
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Title: PERSONALITY SCALE CONSTRUCTION USING LATENT SEMANTIC ANALYSIS AS AN ITEM ANALYSIS METHODOLOGY
Creator: Pollak, Pamela Elizabeth
Date: 2012-05-07, 2012-05
Description: Linguistics has played an integral role throughout the history of personality scale development. The lexical hypothesis, which implies that by...
Show moreLinguistics has played an integral role throughout the history of personality scale development. The lexical hypothesis, which implies that by analyzing natural language personality will be understood because all personality is described in language, is the basis for personality scale construction. Despite the important role that language plays in describing personality, psychometric practice has traditionally focused on data analysis, rather than quantitative linguistic analysis when constructing personality scales. This study used a relatively new quantitative linguistics technique, Latent Semantic Analysis (LSA), to construct personality scales. Using an archival sample of N=501 with over n>1000 items, personality scales were constructed to measure aspects of the 16PF Questionnaire and the Big Five model. Scales created using traditional approaches were compared to scales created using LSA in terms of internal consistency reliability, construct validity and convergent validity, predicting five behavioral clusters of self-reported behaviors (e.g., drug-use, undependability, friendliness, creativity and erudition). Results from this study revealed that compared to scales created using a traditional approach, scales constructed using LSA had lower reliabilities, but mostly similar patterns of convergent validity and evidence of substantial construct validity.
Ph.D. in Psychology, May 2012
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Title: GUARANTEED ADAPTIVE UNIVARIATE FUNCTION APPROXIMATION
Creator: Ding, Yuhan
Date: 2015, 2015-12
Description: Numerical algorithms for univariate function approximation attempt to provide approximate solutions that differ from the original function by...
Show moreNumerical algorithms for univariate function approximation attempt to provide approximate solutions that differ from the original function by no more than a user-specified error tolerance. The computational cost is often determined adaptively by the algorithm based on the function values sampled. While adaptive algorithms are widely used in practice, most lack guarantees, i.e., conditions on input functions that ensure the error tolerance is met. In this dissertation we establish guaranteed adaptive numerical algorithms for univariate function approximation using piecewise linear splines. We introduce a guaranteed globally adaptive algorithm, funappxglobal g, in Chapter 2, along with sufficient conditions for the success of funappxglobal g. Two-sided bounds on the computational cost are given in Theorem 1. These bounds are of the same order as the computational cost for an algorithm that knows the infinity norm of the second derivative of the input function as a priori. Lower bound on the complexity of the problem is also provided in Theorem 3. To illustrate the advantages of funappxglobal g, corresponding numerical experiments are presented in Section 2.7. The cost of a globally adaptive algorithm is determined by the most peaky part of the input function. In contrast, locally adaptive algorithms sample more points where the function is peaky and fewer points elsewhere. In Chapter 3, we establish a locally adaptive algorithm, funappx g, with sufficient conditions for its success. An upper bound on the computational cost is also given in Theorem 4. One GUI example is presented to show how funappx g works. Some interesting function approximation problems in computational graphics are also presented. The key to analyzing these adaptive algorithms is looking at the error for cones of input functions rather than balls of input functions. Non-convex cones provide a setting where adaption may be beneficial.
Ph.D. in Applied Mathematics, December 2015
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Title: A BAYESIAN UPDATING APPROACH IN STRUCTURAL HEALTH MONITORING FOR DAMAGE DETECTION AND ASSESSMENT
Creator: Dirbaz, Mojtaba
Date: 2013, 2013-05
Description: The primary goal of Bridge Condition Assessment (BCA) is to determine the condition of a bridge to prevent any catastrophic failure as well as...
Show moreThe primary goal of Bridge Condition Assessment (BCA) is to determine the condition of a bridge to prevent any catastrophic failure as well as to enhance the structure’s safety and serviceability. The structural health and condition of in-service bridges is generally assessed through visual inspections and nondestructive testing and evaluation (NDT/NDE) methods conducted on a pre-set schedule. However, the ratings obtained from current visual inspections on a bridge are subjective, and do not include the uncertainty inherent in the results. Moreover, the condition ratings are often based on independent inspections and do not take into account the dependence of results on previous conditions of a bridge and prior condition ratings compiled for it. Furthermore, there is also a certain level of uncertainty involved in relating subjective ratings to the actual condition of the bridge. This study is aimed at conducting a research on damage detection of existing bridges utilizing available information on their structural conditions. The first part of the research focuses on a new method for assessing the condition of a bridge based on subjective ratings obtained for the bridge. This method will hereafter be referred to as Bayesian Bridge Condition Assessment (BBCA). BBCA consists of three parts: (1) identification of condition states for structural components, (2) determination of a Damage Index (DI), a parameter to describe the extent of damage to a structural component, and (3) determination of an Updated Damage Index (UDI) using Bayesian updating approach. UDI offers an enhanced measure that incorporates not only the relation between subjective rating and the structure’s health condition, but also the significance of new information as it becomes available. The basic assumptions and x general formulations of the Bayesian updating method is presented. Numerical illustrations are provided to demonstrate the applicability of the method to highway bridges. It is shown that the method described in this study is especially applicable to bridges for which visual inspection data are compiled on a periodic basis. One of the methodologies for damage detection and assessment is to use sensor data for identifying the modal characteristics of the structure. The second part of this research focuses on improving upon damage detection methods using sensor and/or modal data. Thus a new method for damage detection and assessment of structures using finite element analysis, and modal data is developed and demonstrated. This method will hereafter be referred to as Bayesian Structural Condition Assessment (BSCA). Using this method, (1) a Finite Element (FE) design model of the structure (undamaged) is constructed; (2) the measured modal data is updated using a Bayesian framework; and (3) the FE model of existing structure (with possibility of damage) is obtained using updated modal data based on an iterative optimization method that is used in estimating the stiffness of the damaged structure. Using these steps, the location and extent of any possible damage is then determined based on the difference between a structural element stiffness for the “as built condition” and “damaged condition.” Several numerical illustrations are presented to demonstrate the capability of the method to detect the location and extent of the damage. This method has been applied to a structural health monitoring benchmark problem; and it has been shown that it can identify the location and extent of damage with more accuracy than most other existing models. Keywords: Bayesian Updating, Condition Assessment of Structures, Modal Data, Visual Inspections, Finite Element Model, Bridges
PH.D in Structural Engineering, May 2013
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Title: THE CONTRIBUTIONS OF SPATIAL, VERBAL, AND ANALYTICAL SKILLS TO PROBLEM-SOLVING PERFORMANCE
Creator: Foster, Ardyth C.
Date: 2012-12-18, 2012-12
Description: ABSTRACT The purpose of this study was to examine the existence and strength of relationships between students’ cognitive skills and...
Show moreABSTRACT The purpose of this study was to examine the existence and strength of relationships between students’ cognitive skills and mathematical problem-solving performance. Specifically, relationships between students’ verbal, spatial, and analytical skills and their problem-solving performance on items that require a verbal response, items that require a spatial response, and overall problem-solving performance were investigated. A review of the literature also revealed assumptions of close links between verbal and logical/analytical skills, resulting in a lack of assessment of these skills as separate constructs. This study therefore sought to measure each of the cognitive skills separately in order to clearly establish the existence and strength of any pair-wise relationships among the cognitive skills. Ninety-eight students from the fifth- through eighth-grades were administered assessments of verbal skills, spatial skills, and logical/analytical skills, as well as a problem-solving instrument that consisted of a verbal (PST-Verbal) subtest and a spatial (PST-Spatial) subtest. The results indicated statistically significant relationships between students’ cognitive skills and problemsolving performance on the PST-Verbal subtest, the PST-Spatial subtest, and overall problem-solving performance. Surprisingly stronger relationships were found, however, between spatial skills and PST-Verbal performance than between verbal skills and PSTVerbal performance, and stronger relationships were found between verbal skills and PST-Spatial performance than between spatial skills and PST-Spatial performance. Statistically significant pair-wise relationships were also found among the cognitive skills, with the strongest pair-wise relationship existing between verbal and analytical viii skills. The relationship between verbal and spatial skills, although not as strong as the one that exists between verbal and analytical skills, was also quite strong.
PH.D in Mathematics Education, December 2012
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Title: TWO-DIMENSIONAL AND AXISYMMETRIC BUBBLE RISE USING THE LEVEL SET METHOD
Creator: Dominik S, Michael
Date: 2013, 2013-07
Description: Gas bubbles in liquids are important in many industries, including power gen- eration, steel making, as well as chemical and waste water...
Show moreGas bubbles in liquids are important in many industries, including power gen- eration, steel making, as well as chemical and waste water treatment. A fundamen- tal understanding of the bubble rising physics is helpful in many practical applica- tions. A new level set code for incompressible, multiphase ows using the vorticity- streamfunction formulation in both two-dimensional and axisymmetric cases has been developed. The level set method is well suited to treating multiphase ows having complex interface shapes that may undergo topological changes such as merging and splitting of bubbles. Previous numerical and experimental results for single and mul- tiple bubbles are used to determine the numerical parameters that should be used for the new code and to demonstrate the accuracy of the model. The shape and ter- minal velocities of air bubbles in mineral oil and water are found to duplicate other experimental and calculated results very closely. Results have been compared from two-dimensional and axisymmetric versions of the code for bubbles merging with var- ious surface tension. It is found that prior to merging of the bubbles, the results for velocities and bubble shapes are very similar. However, surface tension is found to have a greater in uence on the axisymmetric results. Once the bubbles merge, the combined bubble evolves toward the same shape and terminal velocity of a single bub- ble having the same volume. The initial acceleration of a single air bubble in water is analyzed and found to be approximately 3:3g, not 2g, which is the predicted value from added mass analysis based on potential ow theory. When the liquid density is increased, the acceleration is also found to increase.
PH.D in Mechanical and Aerospace Engineering, July 2013
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Title: EARLY CHILDHOOD RISK FACTORS FOR EXECUTIVE DYSFUNCTION IN A SAMPLE OF SCHOOL-AGED CHILDREN
Creator: Grahovec, Morgan Carey
Date: 2014, 2014-12
Description: The purpose of the present study was to explore whether early childhood factors influence executive function scores, as determined by...
Show moreThe purpose of the present study was to explore whether early childhood factors influence executive function scores, as determined by objective neuropsychological tests and subjective parent and teacher ratings, in a diverse sample of school age children. Data was collected longitudinally over four different visits that corresponded to childhood development (7.76 months, 20 months, 38 months, and 7 years of age). The independent variables examined in the present study included environmental, sociodemographic, and neuropsychological data from the first three time points. At Time 1, the independent variables were SES at Time 1, infant birth weight, maternal body mass index, parental stress at Time 1, and the psychomotor development score at Time 1. At Time 2 and Time 3, the independent variables were SES, parental stress, the sleep problems composite, the DSM-IV ADHD composite, and the psychomotor development index score. Results indicated that overall, maternal pre-pregnancy body mass index, the psychomotor development index score, and family socioeconomic status were the only significant predictors from the first three time points of variance in the Time 4 executive functions as measured by the neuropsychological assessments. The findings showed an inverse relationship between maternal BMI and neuropsychological executive functions, indicating that as BMI increased, executive functioning decreased. A positive relationship between family SES and neuropsychological EF was found, indicating that children from higher SES families performed better on measures of executive functions, as expected. Similarly, a positive relationship was found between psychomotor functions at Time 3 and executive functions at Time 4, which was also in the expected direction. In contrast, subjective parent stress and the DSM-IV ADHD scores were the only significant predictors of the Time 4 executive functions as measured by the parent and teacher ratings. An inverse relationship between parent stress and executive functions was found at all three initial time points, revealing that parents who experience more subjective stress also have children with lower executive functions per parent and teacher report at age 7. A positive relationship was shown between the DSM-IV ADHD composite at Time 3 and the parent/teacher composite score of executive functions at Time 4. This means that children with low executive functions per the parent/teacher composite at Time 4 also had parents and teachers who endorsed greater ADHD symptomatology at Time 3. Subjective parent stress was particularly notable because it was the only independent variable for either of the two dependent variables that was significant across all three of the initial time points. The longitudinal design of this study allowed for the confirmation of the hypothesis that there are significant variables in early childhood that are associated with executive functions later in life. This knowledge has important implications because the more that is understood about executive functioning in children, the more it will be possible to provide meaningful interventions that can maximize a child’s development of this critical skill set.
Ph.D. in Psychology, December 2014
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