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Title: Performance Improvement of Wide-Area-Monitoring-System (WAMS) and Applications Development
Author: Zhao, Jiecheng
Publication Date: 2018-05
Publication Type: doctoral dissertation
Collection: Graduate Theses and Dissertations
PDF: PDF
Abstract: Wide area monitoring system (WAMS), as an application of situation awareness, provides essential information for power system monitoring, planning, operation, and control. To fully utilize WAMS in smart grid, it is important to investigate and improve its performance, and develop advanced applications based on the data from WAMS. In this dissertation, the work on improving the WAMS performance and developing advanced applications are introduced. To improve the performance of WAMS, the work includes investigation of the impacts of measurement error and the requirements of system based on WAMS, and the solutions. PMU is one of the main sensors for WAMS. The phasor and frequency estimation algorithms implemented highly influence the performance of PMUs, and therefore the WAMS. The algorithms of PMUs are reviewed in Chapter 2. To understand how the errors impact WAMS application, different applications are investigated in Chapter 3, and their requirements of accuracy are given. In chapter 4, the error model of PMUs are developed, regarding different parameters of input signals and PMU operation conditions. The factors influence of accuracy of PMUs are analyzed in Chapter 5, including both internal and external error sources. Specifically, the impacts of increase renewables are analyzed. Based on the analysis above, a novel PMU is developed in Chapter 6, including algorithm and realization. This PMU is able to provide high accurate and fast responding measurements during both steady and dynamic state. It is potential to improve the performance of WAMS. To improve the interoperability, the C37.118.2 based data communication protocol is curtailed and realized for single-phase distribution-level PMUs, which are presented in Chapter 7. WAMS-based applications are developed and introduced in Chapter 8-10. The first application is to use the spatial and temporal characterization of power system frequency for data authentication, location estimation and the detection of cyber-attack. The second application is to detect the GPS attack on the synchronized time interval. The third application is to detect the geomagnetically induced currents (GIC) resulted from GMD and EMP-E3. These applications, benefited from the novel PMU proposed in Chapter 6, can be used to enhance the security and robust of power system.

Title: Dissecting Circadian Rhythm in Kalanchoë fedtschenkoi, a Model Species for Crassulacean Acid Metabolism Research
Author: Moseley, Robert C.
Publication Date: 2018-08
Publication Type: doctoral dissertation
Collection: Graduate Theses and Dissertations
PDF: PDF
Abstract: The circadian clock plays a major role in the temporal regulation of an organism’s metabolism and physiology. This role is even more important in plants due to their sessile lifestyle as it provides a fitness advantage by synchronizing internal metabolic and physiological processes with periodic environmental stimuli. A prime example of the importance of the circadian clock in plants can be seen in plants with crassulacean acid metabolism (CAM) photosynthesis. In comparison with C₃ [C three] or C_{4_{[C four] photosynthesis, CAM enhances water-use efficiency via inverted day/night stomatal movement pattern (i.e., stomata close during day and open at night). Also, CAM improves photosynthetic efficiency through a carbon concentration mechanism centered on a temporal separation of carbon dioxide fixation relative to C₃ photosynthesis. These advantages of CAM have garnered increased interest in understanding the molecular mechanism of CAM pathway. However, little is known about the regulatory networks controlling the temporal phases of CAM. The goal of this research is to better understand how the circadian clock regulates CAM-related processes and how it possibly influenced the evolution of CAM.

Through the use of various omics resources and computational methods and tools, the rhythmic transcriptomes of the model obligate CAM species, Kalanchoë fedtschenkoi and the model C₃ species, Arabidopsis thaliana were examined and compared. Similarities and differences in rhythmicity of gene expression were observed between these two species, leading to testable hypotheses on the circadian clock’s role in CAM and its evolution. Furthermore, several candidate clock genes in K. fedtschenkoi were predicted as new members of the core clock network and the circadian output network. Evidence in support of the core clock network impacting the inversion of stomatal movement in K. fedtschenkoi was generated through use of gene regulation inference and an expanded list of stomata-related genes. Together, the results from this research provide a reduction in the hypothesis space for investigating the circadian regulation of CAM.}}

Title: Quantification of Hydrogen-Helium Retention in Tungsten Using Laser Induced Breakdown Spectroscopy Coupled with Laser Ablation Mass Spectrometry
Author: Shaw, Guinevere Chamberlain
Publication Date: 2018-08
Publication Type: doctoral dissertation
Collection: Graduate Theses and Dissertations
PDF: PDF
Abstract: Tungsten (W) has been selected for the ITER divertor because of its high melting temperature, low sputtering yield, and high thermal conductivity. During deuterium/tritium (D/T) plasma exposure in ITER, a large flux (10²⁴m^-2s^-1) of relatively low-energy (100 eV) of D/T plus helium (He) will strike the divertor. The resulting plasma surface interactions (PSI) will lead to surface damage and deformation such as bubble formation, surface blistering and/or erosion, and tritium retention. Experiments have shown that the formation of helium bubbles can have a direct effect on hydrogen retention, although the extent is not fully known. This dissertation has developed and demonstrated two new, complementary laser-based characterization techniques (LIBS and LAMS) for assessing gas concentrations in nuclear materials as a function of spatial position (depth below the surface), with an emphasis on assessing the He-H interaction synergies in tungsten that are expected to impact tritium retention in the ITER divertor and future fusion reactors. In the newly established ultrahigh vacuum setup, the LIBS capability is coupled with the ability to simultaneously pump the ablated gases into a quadrupole mass spectrometer in an existing thermal desorption system (TDS) to simultaneously (although with a small time delay) measure the ion current of the detected gas species in a QMS, this capability we define as LAMS. The gas fluxes measured in LAMS are converted to an absolute quantity of measured gas per laser ablation pulse through calibration with known leak volumes in the TDS. Results of gas concentration as a function of depth in tungsten are shown following exposure to various fluences and plasma configurations, as well as compared to other surface gas evaluation techniques. Altogether this dissertation provides significant new results that: demonstrate the ability of LIBS and LAMS to perform depth dependent gaseous species concentration measurements in nuclear materials; offer new data that comprehensively reflects the complex He-H synergistic interactions and the role of He on tritium retention expected in the ITER tungsten divertor; and provide depth dependent concentration measurements (in addition to integrated retention values) for validation of multiscale models.

Title: How 19th Century District Physicians Constructed the Category of "Volksmedizin"
Author: Culp, Alyssa Nicole
Publication Date: 2018-05
Publication Type: masters thesis
Collection: Graduate Theses and Dissertations
PDF: PDF
Abstract: Over the nineteenth century, medicine in Germany professionalized and Bavaria reformed and centralized its government. The process of professionalization involved academic physicians wresting authority and control from a variety of other practitioners. Yet as my thesis will show, they did so in conversation with those practitioners. Using district medical officers’ reports, this thesis examines how in the late nineteenth century these district physicians constructed the category of Volksmedizin to solidify academic physicians’ authority in medical practices. District physicians were implemented in various rural districts of Bavaria to care for the poor and rural citizens, as well as produce medical topographical and ethnographical information for the Bavarian government. These reports were required by the Bavarian government to help assess the rural regions, their health, practices, and beliefs. While extensive research has been published on these district physicians and their reports, the actual labeling and conceptualization of Volksmedizin and its meaning to these physicians has largely been ignored. Volksmedizin was constructed as a category to distinguish “medicine” from the healing of rural practitioners. Utilizing doctors’ reports to the Bavarian government as well as other primary and secondary source material, this thesis will address the following historical concerns: How did Volksmedizin come to exist as a category? How did the district physician’s role, through the policies of the Bavarian government, change during the late nineteenth and early twentieth centuries? How did the development of medicine fundamentally alter the conceptualization of Volksmedizin and rural practices? Utilizing physician’s reports, this thesis will answer these questions to create a new conversation about the conceptualization of Volksmedizin, and the process in which district court physicians constructed this category.

Title: UNDERSTANDING THE ROLE OF POWER IN INTERDISCIPLINARY, UNDERGRADUATE, STUDENT TEAMS: A CRITICAL DISCOURSE ANALYSIS
Author: Arce-Trigatti, Andrea Lucia
Publication Date: 2018-05
Publication Type: doctoral dissertation
Collection: Graduate Theses and Dissertations
PDF: PDF
Abstract: This dissertation is a cultural studies project that aims to understand how power manifests and influences knowledge construction between students working in an undergraduate, interdisciplinary, collaborative learning environment. Power – which holds the potential to empower and/or silence students - is intrinsic in social interaction and therefore inherent in collaboration. Exploring how power influences new knowledge construction in undergraduate, collaborative learning environments has the potential to uncover what type of interactions are valued and integrated or marginalized and excluded as part of these communicative exchanges. The purpose of this dissertation is thus not only to improve student learning within collaborative contexts, but also to further the implications to teaching that could help advance interdisciplinary communication and new knowledge construction. To explore these dynamics, a two part analysis employing James Gee’s approach to critical discourse analysis was applied to archival data collected from an undergraduate interdisciplinary course entitled, Clinical Immersion at Disciplinary Interfaces (CIDI). This unique, interdisciplinary course required teams composed of chemical engineering and nursing students to develop a prototype of innovative technology that addressed real-world problems in the healthcare profession. The findings emphasize that the manifestation of power and its influence on knowledge construction was primarily accomplished via students’ association with a specific disciplinary cultural model. The affiliation to a specific disciplinary cultural model determined several of the ways in which students engaged within particular social contexts embedded within the CIDI course including: how they positioned themselves (as either insiders or outsiders within that space); their expectations regarding how they understood that space and made situated meanings; and ultimately, their perceived ability to contribute within that space based on their fluency of the associated social language or Discourses. Utilizing a cultural studies lens, scholarship from this field of study is integrated to emphasize how manifestations of power impacted the context of the CIDI course in three ways: through space, language, and disciplinary beliefs. Five pedagogical implications are underscored as part of the concluding remarks.

Title: Characterizing the Streamwise Development of Surface Roughness Effects on a Supersonic Boundary Layer
Author: Kocher, Brian Douglas
Publication Date: 2018-05
Publication Type: masters thesis
Collection: Graduate Theses and Dissertations
PDF: PDF
Abstract: Two-component particle image velocimetry was employed to measure the effects of the mechanical distortions caused from surface roughness topologies on a Mach 2 boundary layer. The first goal of this study was to characterize the mechanical responses of the supersonic boundary layer to various roughness topologies. These responses were characterized in ensemble averaged mean velocity characteristics as well as turbulent intensity responses through the Reynolds Stresses. The second goal was to characterize the streamwise development of the mechanical distortions over a diamond roughness topology. Measurements were taken at three streamwise measurement locations to measure the streamwise mechanical distortion development. Lastly, near-wall streamwise-elongated coherent structures were characterized utilizing a streamwise-spanwise oriented laser sheet. Instantaneous velocity vector fields and two point autocorrelations were used to characterize the spatial orientation of the near-wall coherent structures. Baseline characteristics of the supersonic boundary layer were determined over a hydraulically smooth floor insert. The mean and turbulent statistics compare well to other results when scaled by the roughness friction velocity. Ensemble averaged outer-scaled streamwise velocity profiles showed a velocity deficit in the near-wall region. Inner-scaled boundary layer profiles showed a downward vertical shift of 3 and 4.5 for the diamond roughness and realistic roughness topologies, respectively. These values show similar mechanical responses to the results seen by Ekoto et al.[3] in a Mach 2.86 boundary layer. The roughness effects were shown to increase in magnitude along the streamwise distance.

Title: Multi-criteria Decision Analysis Applied to a Potential U.S. Commercial Spent Nuclear Fuel Allocation Queue Strategy
Author: Joseph, Robert Anthony, III
Publication Date: 2018-05
Publication Type: doctoral dissertation
Collection: Graduate Theses and Dissertations
PDF: PDF
Abstract: Although work has been done on a wide variety of fields in multi-criteria decision analysis, no literature was found that has specifically studied the development of a spent nuclear fuel (SNF) allocation queue strategy to maximize value to decision maker (DM) based on multiple objectives (allocation queue will be mostly used in this document as a shortened version of this, but allocation queue and allocation queue refer to this same thing). In this document, the DM is the person or persons who ultimately decide what allocation queue is selected. Previous work by Petersen [1] researched optimizing the order in which SNF is removed from nuclear reactor sites with the goal of reducing the number of years after all reactors on a site shut down by when all fuel is cleared from a site. This research proposal seeks to build on those methods to optimize the allocation queue by employing multiple criteria, because the development of allocation strategies for clearing nuclear reactor sites is expected to depend upon several other factors in addition to minimizing the number of Shutdown Reactor Years (SRY). Shutdown reactor years are the cumulative number of years that reactor sites have SNF remaining on-site after they are shut down summed over the entire reactor fleet. In this dissertation, a new model has been developed with the ability to consider a multiple number of DM’s preferences when developing an optimal allocation queue (in terms of maximizing value to the DM). Unlike traditional multi-objective evaluations where potential allocation strategies are developed manually, and the results compared after analyzing each scenario separately, the model was developed to search for optimum allocation strategies based on DM’s preferences. A Chebyshev integer programming method was developed for this application and the results herein provided show that the new model, denoted as the Tractable Validation Model for Value (TVMV), performs as intended. Additionally, major assumptions that affect the TVMV were explored to investigate the implications of different system assumptions. These parameters include the year in which acceptance from reactor sites begins, the maximum fleet-wide acceptance rate per year, the maximum number of canisters that can be accepted from operating or shutdown reactors in each year, and the assumed storage and transportation cask thermal limits.

Title: An Ultra-Low-Power Track-and-Hold Amplifier
Author: Niemela, George Earl
Publication Date: 2018-08
Publication Type: masters thesis
Collection: Graduate Theses and Dissertations
PDF: PDF
Abstract: The future of electronics is the Internet of Things (IoT) paradigm, where "always-on" devices and sensors monitor and transform everyday life. A plethora of applications (such as navigating drivers past road hazards or monitoring bridge and building stresses) employ this technology. These unattended ground-sensor applications require decade(s)-long operational life-times without battery changes. Such electronics demand stringent performance specifications with only nano-Watt power levels. This thesis presents an ultra-low-power track-and-hold amplifier for such systems. It serves as the front-end of a SAR-ADC or the building block for equalizers or filters. This amplifier's design attains exceptional hold times by mitigating switch subthreshold leakage and bulk leakage. Its novel transmission-gate topology achieves wide-swing performance. Though only consuming 100 pico-Watts, it achieves a precision of 7.6 effective number of bits (ENOB). The track-and-hold amplifier was designed in 130-nm CMOS.

Title: Children and Transitional Justice in Nepal: Entrenched Violence and Marginalized Perspectives
Author: Billingsley, Krista Elizabeth
Publication Date: 2018-05
Publication Type: doctoral dissertation
Collection: Graduate Theses and Dissertations
PDF: PDF
Abstract: In this dissertation, I argue for an approach to transitional justice that analyzes the diverse and dynamic ways in which people experience armed conflict and its aftermath. I question what actually changes during a state’s “transitional period” and illuminate how transitional justice is utilized, politicized, and manipulated by powerful actors. Throughout this dissertation, I examine the varied experiences of people who endured gross violations of human rights as children, according to international law, and who are now, within that legal framework, adults. I follow the lives of victims of Nepal’s armed conflict as they transition out of what is recognized in international law as a temporary phase known as “childhood” and explore what they recognize as constant and temporal in their own lives as the Nepali state undergoes its own transition, also argued to be a temporary phase, transitional justice. I inquire how diverse identities and patterned inequality are reconstituted through processes of transitional justice and contend the façade of the inclusion serves as a distraction from claims for equitable access to power and resources. A key argument of this dissertation is that the performance of transitional justice in Nepal, including the performance of redressing human rights violations experienced by victims and addressing the needs of the most vulnerable victims (e.g. children), functions to conceal international complicity in as well as the state’s commitment to maintaining structural inequality. Following ten years of armed conflict to ameliorate historically sedimented inequity, state-led transitional justice mechanisms have served to entrench the exclusion of economically, politically, and socially marginalized groups and ensure Nepalis’ continued distrust in the national government. Thus, while addressing structural inequality may be beyond the reach of normative transitional justice mechanisms, the Nepali context demonstrates how processes of transitional justice cannot redress conflict-era gross violations of human rights without redressing inequitable systems of power.

Title: Computational simulations in materials for energy applications 1. Crystal and electronic structure in Ln-U-O compounds. 2. Dynamics of point defect interaction with dislocations in bcc iron.
Author: Casillas Trujillo, Luis Alberto
Publication Date: 2018-05
Publication Type: doctoral dissertation
Collection: Graduate Theses and Dissertations
PDF: PDF
Abstract: Nuclear energy is a viable solution to the world’s energy demands. Nuclear energy applications involve rich and complex physics, with high energy events, the incorporation of fission products, and the production of point and extended defects. All these phenomena have an impact on the microstructure of the constituent materials and represent efficiency and safety concerns. A mature understanding of the microstructural evolution of the component materials in the nuclear reactor core is essential to have a safe and reliable process. Experimental investigation of materials in radiation environments is difficult and expensive, making computational simulations a suitable alternative. In this dissertation, employ computational methods to study the microstructural evolution of both nuclear fuel and the iron based reactor structural components, and the impact on their material properties. In the nuclear fuel side, we investigate the crystallographic and electronic structure of Ln-U-O compounds that may be formed inside nuclear fuel operational life by the incorporation of lanthanide fission products using density functional theory (DFT). We used a layered atomic model to propose ordered structures and compared their stability to disordered phases. We also employed the atom-in-molecule approach to study the oxidation state of uranium atoms, and the iconicity/covalency of the U-O bonds. In the structural components side, we studied the migration mechanisms of self-interstitial dumbbells and vacancies around single edge or screw dislocations. The actual saddle point energy and configuration as a function of position with respect of the dislocation core was calculated with the self-evolving atomistic kinetic Monte Carlo (SEAKMC) method, and used this data as an input for KMC calculations. This allowed the analysis of the migration paths, the range of interaction of point defects with dislocations, and the preferential absorption of self-interstitial dumbbells over vacancies, known as dislocation bias, which is responsible for swelling in irradiated materials. The understanding of the mechanism responsible for the microstructural changes, and how these changes impact the material properties is a key aspect to be able to develop materials with enhanced radiation resistance, and achieve high performance under extreme conditions that are vital for nuclear energy generation with improved efficiency and safety.

Title: Understanding what influences engineering faculty course decisions using activity systems analysis
Author: Skutnik, Anne Leslie
Publication Date: 2018-05
Publication Type: doctoral dissertation
Collection: Graduate Theses and Dissertations
PDF: PDF
Abstract: Engineering faculty members often publish about their courses, but what is lacking from these articles is an understanding of why they make the decisions they make during the course design activity. Using cultural historical activity theory as a theoretical framework, this dissertation looks at how seven award-winning engineering faculty members approach their syllabus and their course. The course syllabus acted as a tool for faculty to both share about their course and course design process, and to communicate their beliefs to their students and to others within their disciplinary communities. However, the course syllabus was not always used in the way that participant faculty intended, and was often under-utilized by many of the students. As a result, participant faculty relied on their beliefs about teaching and learning, and the stakeholder position they held in their departments, as tools as they wrote their course syllabuses and taught their courses.

Title: Acoustic monitoring of wildlife in inaccessible areas and automatic detection of bird songs from continuous recordings
Author: Hockman, Emily Vera
Publication Date: 2018-05
Publication Type: doctoral dissertation
Collection: Graduate Theses and Dissertations
PDF: PDF
Abstract: The use of new technology for wildlife monitoring comes with both possible benefits and challenges. Unmanned aerial vehicles (UAVs) and automatic recording units (ARUs) can allow researchers to automatically record videos, photographs, and audio recordings of animals in unusual or inaccessible locations. However, new acoustic monitoring techniques require innovative methods to extract and utilize data from acoustic recordings. In this project we developed novel technology to record bird songs in inaccessible areas and demonstrated a useful method for extracting and classifying songs from continuous recordings. The autonomous aerial acoustic recording system (AAARS) was a UAV developed at the University of Tennessee capable of generating high-quality WAV recordings of bird songs in a variety of landscapes. The AAARS was completely silent in flight controlled by a ground-based computer monitoring station. I developed a model to convert the AAARS GPS-based flight path into a microphone exposure surface to relate species-specific acoustic signals recorded to area of microphone coverage. The vocalizations per unit area per unit time for a given focal species could then be used as an index of relative abundance or as an input in density estimation. Once collected, extraction and classification of birdsongs from acoustic recordings remains a major technological challenge. I used quadratic discrimination analysis to differentiate between inter- and intra-specific bird songs using up to sixteen acoustic measurements on human-extracted signals from audio spectrograms of five focal songbird species. Measurement-based classification was successful at separating the five species apart with only ≤5% classification error. I then used a template-matching model to extract target birdsongs from continuous field recordings and investigated the efficiency of different analytical options for classification of five focal songbird species. Decision trees, neural networks, and quadratic discriminant analysis all produced similar classification results. The means to optimize the analytical approach varied by species. I concluded that a species-specific approach should be used to accurately extract and classify songs from continuous recordings.

Title: A DELAYED PARITY GENERATION CODE FOR ACCELERATING DATA WRITE IN ERASURE CODED STORAGE SYSTEMS
Author: Mousavicheshmehkaboodi, Sara
Publication Date: 2017-12
Publication Type: masters thesis
Collection: Graduate Theses and Dissertations
PDF: PDF
Abstract: We propose delayed parity generation as a method to improve the write speed in erasure-coded storage systems. In the proposed approach, only some of the parities in the erasure codes are generated at the time of data write (data commit), and the other parities are not generated, transported, or written in the system until system load is lighter. This allows faster data write, at the expense of a small sacrifice in the reliability of the data during a short period between the time of the initial data write and when the full set of parities is produced. Although the delayed parity generation procedure is anticipated to be performed during time of light system load, it is still important to reduce data traffic and disk IO as much as possible when doing so. For this purpose, we first identify the fundamental limits of this approach through a connection to the well-known multicast network coding problem, then provide an explicit and low-complexity code construction. The problem we consider is closely related to the regenerating code problem. However, our proposed code is much simpler and has a much smaller subpacketization factor than regenerating codes. Our result shows that blindly adopting regenerating codes in this setting is unnecessary and wasteful. Experimental results confirm that to obtain the improved write speed, the proposed code does not significantly increase computation burden.

Title: Influence of Cruciate Retaining, Posterior Stabilized and Bi-Cruciate Stabilized Total Knee Replacement Designs on Gait Mechanics during Ramp and Level Walking
Author: Wen, Chen
Publication Date: 2018-05
Publication Type: doctoral dissertation
Collection: Graduate Theses and Dissertations
PDF: PDF
Abstract: Twenty-five, 5 Bi-cruciate stabilized (BCS), 10 Cruciate Retaining (CR) and 10 Posterior Stabilized (PS), total knee replacement (TKR) patients and 10 healthy controls performed uphill and downhill walking on different slopes using a force platform and an instrumented ramp system. Studies one and study two examined the knee biomechanics and knee joint muscle EMG activity of TKR patients and healthy control during uphill and downhill walking at 0° (level walking), 5°, 10° and 15°, respectively. Study three compared knee biomechanics of patients with three different types of TKR implants to healthy controls during walking up and down on a 10° ramp. Study one found TKR patients had lower peak knee extension moment (KEM) than healthy controls in all uphill walking conditions. The replaced limbs showed lower peak KEM in 10° and 15° uphill walking than non-replaced limbs. The peak loading-response internal knee abduction moment (KAbM) was greater in level walking compared to 10° and 15° uphill walking. Study two showed that replaced limbs of TKR patients had lower peak loading-response and push-off KEM, and quadriceps electromyography (EMG) activity than non-replaced and matched limb of healthy controls in downhill walking. Greater peak KEM, quadriceps EMG activity were found in downhill walking compared to level walking. Study three showed peak KEM was lower in BCS patients than healthy controls and it was lower in replaced limbs than non-replaced limbs during the 10° uphill walking. Peak loading-response KAbMs were similar between the replaced limbs of three TKR groups and healthy controls in both uphill and downhill walking. Moreover, the replaced limbs had lower peak loading-response and push-off KEMs than non-replaced limbs in downhill walking. Additionally, peak loading-response KAbM was greater in non-replaced limbs of BCS and PS patients compared to that in their replaced limb. Uphill walking may have the potential to become a safe exercise for unilateral TKR patients, however, downhill walking may not be appropriate to be included in the early-stage rehabilitation exercise protocols for TKR patients. Future studies should investigate rehabilitation strategies to improve the symmetrical knee loading of BCS and PS patients, therefore postponing or avoiding another TKR surgery.

Title: Integration of Rosenbrock-type solvers into CAM4-Chem and evaluation of its performance in the perspectives of science and computation
Author: Sun, Jian
Publication Date: 2018-05
Publication Type: doctoral dissertation
Collection: Graduate Theses and Dissertations
PDF: PDF
Abstract: In this study, the perennial problem of overestimation of ozone concentration from the global chemistry-climate model (CAM4-Chem [Community Earth System Model with chemistry activated]) is investigated in the sense of numerics and computation. The high-order Rosenbrock-type solvers are implemented into CAM4-Chem, motivated by its higher order accuracy and better computational efficiency. The results are evaluated by comparing to the observation data and the ROS-2 [second-order Rosenbrock] solver can reduce the positive bias of ozone concentration horizontally and vertically at most regions. The largest reduce occurs at the mid-latitudes of north hemisphere where the bias is generally high, and the summertime when the photochemical reaction is most active. In addition, the ROS-2 solver can achieve ~2x speed-up compared to the original IMP [first-order implicit] solver. This improvement is mainly due to the reuse of the Jacobian matrix and LU [lower upper] factorization during its two-stage calculation. In order to gain further speed-up, we port the ROS-2 solver to the GPU [graphics processing unit] and compare the performance with CPU. The speed-up of the GPU version with the optimized configuration reaches a factor of ~11.7× for the computation alone and ~3.82× considering the data movement between CPU and GPU. The computational time of the GPU version increases more slowly than the CPU version as a function of the number of loop iterations, which makes the GPU version more attractive for a massive computation. Moreover, under the stochastic perturbation of initial input, we find the ROS-3 [third-order Rosenbrock] solver yields better convergence property than the ROS-2 and IMP solver. However, the ROS-3 solver generally provides a further overestimation of ozone concentration when it is implemented into CAM4-Chem. This is due to the fact that more frequent time step refinements are involved by the ROS-3 solver, which also makes the ROS-3 solver less computationally efficient than the IMP and ROS-2 solvers. We also investigate the effect of grid resolution and it shows that the fine resolution can provide relatively better pattern correlation than the coarse resolution, given the same chemical solver.

Title: A Semantic Unsupervised Learning Approach to Word Sense Disambiguation
Author: Martin, Dian I.
Publication Date: 2018-05
Publication Type: doctoral dissertation
Collection: Graduate Theses and Dissertations
PDF: PDF
Abstract: Word Sense Disambiguation (WSD) is the identification of the particular meaning for a word based on the context of its usage. WSD is a complex task that is an important component of language processing and information analysis systems in several fields. The best current methods for WSD rely on human input and are limited to a finite set of words. Complicating matters further, language is dynamic and over time usage changes and new words are introduced. Static definitions created by previously defined analyses become outdated or are inadequate to deal with current usage. Fully automated methods are needed both for sense discovery and for distinguishing the sense being used for a word in context to efficiently realize the benefits of WSD across a broader spectrum of language. Latent Semantic Analysis (LSA) is a powerful automated unsupervised learning system that has not been widely applied in this area. The research described in this proposal will apply advanced LSA techniques in a novel way to the WSD tasks of sense discovery and distinguishing senses in use.

Title: SIRE CONTRIBUTION TO PREGNANCY ESTABLISHMENT AND MAINTENANCE IN BEEF COWS
Author: Araujo Franco, Gessica
Publication Date: 2018-05
Publication Type: masters thesis
Collection: Graduate Theses and Dissertations
PDF: PDF
Abstract: Pregnancy loss is a major component of reproductive inefficiency and economic loss in both the beef and dairy industry. Research tends to focus on female contribution to pregnancy maintenance and overlook the role of the especially beyond early embryonic development stages. The aim of this study was to identify sires associated with high or low pregnancy loss and to investigate their effect on placental function, using circulating concentrations of pregnancy-associated glycoprotein [PAGs]. For the first part of the study, multiparous beef cows were randomly timed artificially inseminated [FTAI] with semen from either of 6 Angus sires of proven fertility and later, sires were retrospectively classified according to amount of pregnancy loss between days 30 and 100 of gestation. Pregnancies sired by high pregnancy loss sires had lower (P=0.05) circulating PAG concentration compared with pregnancies sired by low embryonic loss. For the second part, cows were artificially inseminated with either Nelore or Angus sires. Cows receiving semen from Nelore sires had greater (P < 0.001) pregnancy rate, greater (P = 0.014) pregnancy loss and lesser (P = 0.002) PAG concentrations at day 30 of gestation compared with cows receiving Angus semen. Estrus expression were evaluated in all cows using detector patches. Cows that expressed estrus prior to FTAI had higher pregnancy rate at day 30 and higher odds of maintaining pregnancy up to day 100 of gestation. Moreover, the effect of estrus in pregnancy rates was highly variable between sires. In summary, PAG concentrations reflected probability of pregnancy maintenance and were influenced by both sire and sire breed used at FTAI. A large variation in the incidence of pregnancy loss was detected among sires that could not be predicted with standard semen fertility evaluations. Exploring the relationship of sire and PAG production might be promising to improve sire selection with regard to pregnancy loss.

Title: Fluid Structure Interaction of Involute Fuel Plates in the High Flux Isotope Reactor Using a Fully-coupled Numerical Approach
Author: Curtis, Franklin Guthrie
Publication Date: 2018-05
Publication Type: doctoral dissertation
Collection: Graduate Theses and Dissertations
PDF: PDF
Abstract: This dissertation describes a fully-coupled (FC), finite-element (FE) based, algorithm for modeling and simulation of the fluid-structure interaction (FSI) of involuteshaped fuel plates used in research reactors; specifically the High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory (ORNL). Following a graded approach to code and model validation, a cylinder in cross-flow benchmark is used to establish flow physics as well as properly coupling the FSI phenomena with increasing complexity. As an interim step toward HFIR LEU fuel plate simulations, three experiments are used for validation. The first, performed by Smissaert, is used to envelope large plate deflections and understand the validity of various fluid boundary conditions for single plate comparisons. Continuing with Smissaert's data, a 5-plate simulation is presented showing the first-ever multi-plate simulation using this FC and FE approach. Second, a vibrating plate, presented by Liu et al., is simulated showing the same technique to encompass self-excited, periodic plate deflections. Lastly, an experiment for the conceptual Advanced Neutron Source Reactor (ANSR) using involute plates is utilized to validate the ability of this FC and FE algorithm to predict the deflections of the involute-shaped plates used in the HFIR. The method shown herein accurately captures the established `S-shaped' deflection of the first mode of the involute plate providing guidance that researchers and designers can utilize in the forthcoming design of the next generation of low-enriched uranium (LEU) fuel plates for the HFIR. A `Lessons Learned' section which describes external routine coupling, geometry and meshing guidance, and solver settings used in the computational platform used to perform these FSI simulations is also provided.

Title: Validation Of Complete Blood Count Methodology, And Determination Of The Relationship Between Endoparasite Load And Erythrocyte Values In New World Camelids
Author: Viesselmann, Lisa C.
Publication Date: 2018-05
Publication Type: masters thesis
Collection: Graduate Theses and Dissertations
PDF: PDF
Abstract: Background: Accurate measurement of RBCs (red blood cells) by automated hematology analyzers such as the ADVIA 120/2120 requires isovolumetric cell sphering; however, camelid RBC membranes are resistant to shape change. There are no published reports of method validation for hematologic analysis of camelid blood. Mycoplasma haemolamae and gastrointestinal nematodes can cause anemia in camelids. Parasite control programs aim to suppress parasite loads without promoting resistance, but there are few evidence-based guidelines for acceptable parasite loads in camelids. Objectives: 1) Demonstrate whether camelid RBCs sphere in the ADVIA sphering reagent, and determine the optimal ADVIA setting for CBC (complete blood count) analysis, 2) Compare M. haemolamae PCR status with RBC values, and 3) Determine the fecal egg count (FEC) threshold above which RBC values are consistently below the median of the reference interval. Methods: Camelid and canine blood were each added to ADVIA sphering reagent or saline, and evaluated by light microscopy for erythrocyte sphering. Camelid blood was analyzed on an ADVIA 120 hematology analyzer using one of three species settings, and values compared to manual measurements, including packed cell volume (PCV), Z2 Coulter counter RBC count, and calculations of other RBC values. Mycoplasma haemolamae was detected by real-time PCR. The number of trichostrongyle eggs per gram (epg) of feces was determined using the Modified McMaster’s test. Results and Conclusions: Camelid erythrocytes do not sphere when mixed with ADVIA sphering reagent. The ADVIA 120 equine setting provides the closest approximations to Z2 counter RBC count estimates, but ADVIA results for most other RBC values appear inaccurate. PCV, hemoglobin, and RBC count are not significantly different between M. haemolamae positive and negative animals, but are significantly lower in animals with FEC> [greater than] 600epg. For all animals with FEC>600epg, RBC values are below the medians of the reference intervals. Positive M. haemolamae PCR is not associated with lower RBC values in healthy camelids, consistent with previous reports that most infections are subclinical. Maintaining FEC below 600 epg is recommended in camelids.

Title: A Resilient Micro-Power Charge Amplifier for Biomedical Applications
Author: Wang, Hanfeng
Publication Date: 2018-05
Publication Type: doctoral dissertation
Collection: Graduate Theses and Dissertations
PDF: PDF
Abstract: It is reasonable to believe, that the world of tomorrow is a surge of the cyberspace, whose interface is knitted by enormous varieties of sensor electronic systems. Biomedical sensor systems gain special interests simply because they save lives. An implanted glucose sensor system acknowledges the diabetes patient a concentration increase before symptoms. A respiratory sensor system may alert the nurse when an apnea is detected. The mass occurrences of medical conditions are uploaded to the database and statistically studied, the results of which are utilized for gross prevention basis. A sensor system as such, usually consists of a transducer that converts the information of interest to electrical energy, a front-end amplifier that buffers the energy to a voltage signal, a data converter that digitize the signal and a transmitter that pass on the information. This dissertation will exclusively discuss the front-end amplifiers. As one of the most common types, a charge-mode amplifier resolves charge amount with a RC fed-back voltage gain circuit configuration, standardly known as charge amplifiers. However, the conventional structure suffers from the tradeoff between leakage current tolerance and signal bandwidth while iterations and modifications in literature failed to address the issue efficiently. A novel approach is proposed in this dissertation that obliterates the aforementioned tradeoff and offers complementary benefits. The resiliency that this structure exhibits bolsters its feasibility to be incorporated in a wide spectrum of applications especially biomedical sensor systems.

The University of Tennessee, Knoxville

TRACE: Tennessee Research and Creative Exchange University Libraries

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