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2017

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Tissue Stretching Device, Usama Ismail, Humza Ismail, Elvir Sarajlic Dec 2017

Tissue Stretching Device, Usama Ismail, Humza Ismail, Elvir Sarajlic

Mechanical Engineering Design Project Class

This tissue loading project consists of designing an apparatus that has two main functions. The first, and most obvious of these, being creating a device that will deform a band or disk of tissue with cells pre-seeded on them uniaxially while recording the stress and strain, specifically strain rate, that is applied to the tissue. While the deformation aspect of this device will be key, an equally important part of this project will be designing a part of our tissue loader that mimics the environmental chamber that the lab already uses or is compatible with the environmental chamber that is …

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Validation Of The Two-Parameter Fracture Criterion Using Critical Ctoa On 7075-T6 Aluminum Alloy, Hasnaa Ouidadi Dec 2017

Validation Of The Two-Parameter Fracture Criterion Using Critical Ctoa On 7075-T6 Aluminum Alloy, Hasnaa Ouidadi

Theses and Dissertations

A two-parameter fracture criterion (TPFC) is used to correlate and predict failure loads on cracked configurations made of ductile materials. The current study was conducted to validate the use of the fracture criterion on more brittle materials, using elastic-plastic finite-element analyses with the critical crack-tip-opening angle (CTOA) failure criterion. Forman generated fracture data on middle-crack tension, M(T), specimens made of thin-sheet 7075-T6 aluminum alloy, which is a quasi-brittle material. The fracture data included a wide range of specimen widths (2w) ranging from 3 to 24 inches. A two-dimensional (2D) finite-element analysis code (ZIP2D) with a ''plane-strain core" option was used …

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Microstructural Behavior And Multiscale Structure-Property Relations For Cyclic Loading Of Metallic Alloys Procured From Additive Manufacturing (Laser Engineered Net Shaping -- Lens), Mohammad Ali Bagheri Dec 2017

Microstructural Behavior And Multiscale Structure-Property Relations For Cyclic Loading Of Metallic Alloys Procured From Additive Manufacturing (Laser Engineered Net Shaping -- Lens), Mohammad Ali Bagheri

Theses and Dissertations

The goal of this study is to investigate the microstructure and microstructure-based fatigue (MSF) model of additively-manufactured (AM) metallic materials. Several challenges associated with different metals produced through additive manufacturing (Laser Enhanced Net Shaping – LENS®) have been addressed experimentally and numerically. Significant research efforts are focused on optimizing the process parameters for AM manufacturing; however, achieving a homogenous, defectree AM product immediately after its fabrication without postabrication processing has not been fully established yet. Thus, in order to adopt AM materials for applications, a thorough understanding of the impact of AM process parameters on the mechanical behavior of AM …

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Field Methods, Sampling Strategies, Historical Documents, And Data Redundancy: A Study Of Historic Tenant Farmsteads In Leflore County, Mississippi, Jayson Jon Zoino Dec 2017

Field Methods, Sampling Strategies, Historical Documents, And Data Redundancy: A Study Of Historic Tenant Farmsteads In Leflore County, Mississippi, Jayson Jon Zoino

Theses and Dissertations

Historic tenant farmsteads are often thought to be redundant archaeological resources because of their limited temporal range and function which acts to limit the diversity of their archaeological assemblages. However, work has not been done that confirms this equivalence, and archaeologists often write off tenant farmsteads as being too modern or too disturbed to warrant investigation. This is a problematic approach as tenant farmsteads are quickly eroding from the American landscape and a representative sample of sites need to be investigated and preserved before they’re gone. This thesis tests different sampling strategies and field methods that may allow for the …

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Impacts Of Immigration Policy Changes On Employment Of Foreign Born Doctorate Recipients, Jun Cheng Dec 2017

Impacts Of Immigration Policy Changes On Employment Of Foreign Born Doctorate Recipients, Jun Cheng

Theses and Dissertations

The H-1B visa program was initiated in 1990 to temporarily hire highly-skilled foreign workers. The H-1B visa program has changed several times since its initiation. One of the most important changes occurred in 2001 when the 21st Century Act exempted individuals employed by institutions of higher education and nonprofit and government research organizations from the H-1B visa cap increasing the number of visas available for foreign high-skilled immigrants. To analyze the impact of policy changes affecting the H-1B program on highly-skilled workers, we study the behavior of foreign-born Ph.D. students who graduated from institutions in the United States over the …

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Demonstration Of Ultra-High Recyclable Energy Densities In Domain-Engineered Ferroelectric Films, Hongbo Cheng, Jun Ouyang, Yun-Xiang Zhang, David J. Ascienzo, Yao Li, Yu-Yao Zhao, Yuhang Ren Dec 2017

Demonstration Of Ultra-High Recyclable Energy Densities In Domain-Engineered Ferroelectric Films, Hongbo Cheng, Jun Ouyang, Yun-Xiang Zhang, David J. Ascienzo, Yao Li, Yu-Yao Zhao, Yuhang Ren

Publications and Research

Dielectric capacitors have the highest charge/discharge speed among all electrical energy devices, but lag behind in energy density. Here we report dielectric ultracapacitors based on ferroelectric films of Ba(Zr0.2,Ti0.8)O3 which display high-energy densities (up to 166 J cm–3) and efficiencies (up to 96%). Different from a typical ferroelectric whose electric polarization is easily saturated, these Ba(Zr0.2,Ti0.8)O3 films display a much delayed saturation of the electric polarization, which increases continuously from nearly zero at remnant in a multipolar state, to a large value under the maximum electric field, leading to drastically improved recyclable energy densities. This is achieved by the creation …

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First Low-Frequency Einstein@Home All-Sky Search For Continuous Gravitational Waves In Advanced Ligo Data, B. P. Abbott, K. Aultoneal, S. Gaudio, K. Gill, B. Hughey, J. W. W. Pratt, E. Schmidt, S. G. Schwalbe, M. J. Szczepańczyk, M. Zanolin, Et Al. Dec 2017

First Low-Frequency Einstein@Home All-Sky Search For Continuous Gravitational Waves In Advanced Ligo Data, B. P. Abbott, K. Aultoneal, S. Gaudio, K. Gill, B. Hughey, J. W. W. Pratt, E. Schmidt, S. G. Schwalbe, M. J. Szczepańczyk, M. Zanolin, Et Al.

Publications

We report results of a deep all-sky search for periodic gravitational waves from isolated neutron stars in data from the first Advanced LIGO observing run. This search investigates the low frequency range of Advanced LIGO data, between 20 and 100 Hz, much of which was not explored in initial LIGO. The search was made possible by the computing power provided by the volunteers of the Einstein@Home project. We find no significant signal candidate and set the most stringent upper limits to date on the amplitude of gravitational wave signals from the target population, corresponding to a sensitivity depth of 48.7 …

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Improved Heuristic Search Algorithms For Decision-Theoretic Planning, Ibrahim Abdoulahi Dec 2017

Improved Heuristic Search Algorithms For Decision-Theoretic Planning, Ibrahim Abdoulahi

Theses and Dissertations

A large class of practical planning problems that require reasoning about uncertain outcomes, as well as tradeoffs among competing goals, can be modeled as Markov decision processes (MDPs). This model has been studied for over 60 years, and has many applications that range from stochastic inventory control and supply-chain planning, to probabilistic model checking and robotic control. Standard dynamic programming algorithms solve these problems for the entire state space. A more efficient heuristic search approach focuses computation on solving these problems for the relevant part of the state space only, given a start state, and using heuristics to identify irrelevant …

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The Cosm Aggregate, Georgia Southern University Dec 2017

The Cosm Aggregate, Georgia Southern University

College of Science & Mathematics: News & Publications (2012-2022)

No abstract provided.

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Costs And Benefits Of Mobility: The Case Of Chinese Seafarers, L Tang, G Chen Dec 2017

Costs And Benefits Of Mobility: The Case Of Chinese Seafarers, L Tang, G Chen

Plymouth Business School

No abstract provided.

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Leadership Frames In Comprehensive Community Colleges: Implications For The Market-Responsive College, David Layne Campbell Dec 2017

Leadership Frames In Comprehensive Community Colleges: Implications For The Market-Responsive College, David Layne Campbell

Theses and Dissertations

Market-responsive college leaders are challenged to navigate external relationships with business and industry, government officials, and community leaders, as well as the resulting pressures of multiple missions of the comprehensive community college. The leaders are faced with three predominant issues involving the market-responsive college and its relationship to the overall comprehensive college. These issues include: (a) its relationship to the transfer role, (b) difficulty of defining and measuring its success, and (c) its placement within the organization. Bolman and Deal’s (2013) leadership frames provide a model to understand how framing by market-responsive college leaders influences their organizations. A qualitative case …

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Effect Of Chitosan On Subterranean Termites (Reticulitermes Spp.) Mortality And Gut Bacterial Community, Olanrewaju Adeyemi Raji Dec 2017

Effect Of Chitosan On Subterranean Termites (Reticulitermes Spp.) Mortality And Gut Bacterial Community, Olanrewaju Adeyemi Raji

Theses and Dissertations

The main objectives of this study were to investigate the applicability of chitosan as an effective wood preservative against subterranean termites, conduct metagenomic analysis of the bacterial hindgut community of Reticulitermes flavipes exposed to chitosan-treated wood, and perform chitosanase activity assay of metagenomics suggested bacterial species potentially responsible for chitosan breakdown. Chitosan showed termiticidal effects on subterranean termites at varying retention levels. Termite mortality increased when exposed to samples treated with higher chitosan concentration solutions. Approximately 40 - 100% of chitosan retained in treated-wood was leached depending on the initial retention. Post-leaching results indicate chitosan is not suitable for protection …

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Effecting Organizational Change At The Macro Level Of Professions, Robert Anthony Green Dec 2017

Effecting Organizational Change At The Macro Level Of Professions, Robert Anthony Green

Theses and Dissertations

Much has been written in academic and popular publications about organizational change. Topics have ranged from case studies to anecdotal stories of how leaders can change an organization. There is little written on changing the culture and vision of a profession at the macro level. This dissertation shows that one key to effecting change within a profession is to educate those at the entrant level and thereby effect change with the profession. Over time, these new entrants to the profession will rise to senior positions and be able to effect greater change through the hiring, training, and mentoring processes inherent …

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Establishing The Structure Function Relationship Of Polypyridyl Ruthenium And Berenil-Type Compounds In The Formation Of Complexes With B-Dna And/Or G-Quadruplex Dna, Clinton Gregory Mikek Dec 2017

Establishing The Structure Function Relationship Of Polypyridyl Ruthenium And Berenil-Type Compounds In The Formation Of Complexes With B-Dna And/Or G-Quadruplex Dna, Clinton Gregory Mikek

Theses and Dissertations

Cancer results from the accumulation of genetic mutations in a normal cell that ultimately result in the expression (or overexpression) of oncogenes. The design of drugs having high affinity for specific DNA sequences or structural motifs is vital to gaining a better understanding of gene expression and to the development of new cancer treatments that are based on turning off oncogene expression. This dissertation presents studies of the binding of two ligand families, Berenil (DMZ), and ruthenium polypyridyl complexes (RPCs), to B-DNA and G-quadruplex (G4) DNA. The structureunction relationships for the interaction of these ligand families with DNA were probed …

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Wastewater Remediation Using Modified Biochars, Griffin Allen Burk Dec 2017

Wastewater Remediation Using Modified Biochars, Griffin Allen Burk

Theses and Dissertations

Water polluted by metals and phosphates can be hazardous to both the environment and human health. The aim of this study was used to improve understanding of the adsorption properties of low-cost, green adsorbents for removal of pollutants from aqueous solution. Biochar was used as an adsorbent, which was produced from the gasification of pine wood waste and the fast pyrolysis of Douglas fir. Biochar is a bio-renewable product that can easily be modified, and the cost is lower compared to other adsorbents like activated carbon. The gasifier produced biochar was modified by coating the biochar surface with chitosan. Douglas …

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A Reconciled Estimation Of The State Of Cryospheric Components In The Southern Andes And California Using Geospatial Techniques, Pushkar Inamdar Dec 2017

A Reconciled Estimation Of The State Of Cryospheric Components In The Southern Andes And California Using Geospatial Techniques, Pushkar Inamdar

Theses and Dissertations

Glaciers are the essential source of fresh water not only to human sustenance, but it is also vital for all lifeforms on earth. Glaciers are also key components in understanding rapid changes in climate. This makes understanding of glacier mass, extent, and overall state essential. In this dissertation, the objective was to analyze the state of snow and ice masses in the mid (California) and low latitude (Chile/Argentina) western American regions using geospatial technology. This study also analyzed the effects of anomalies in snow mass on the regional agricultural practices in California’s Central Valley. In the Southern Andes, the digital …

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A Simulation Of Lfm Pulse-Doppler Radar And An Application Of Cohen-Daubechies-Feauveau Wavelets In Cfar Detection, Aaron Joshua Wright Dec 2017

A Simulation Of Lfm Pulse-Doppler Radar And An Application Of Cohen-Daubechies-Feauveau Wavelets In Cfar Detection, Aaron Joshua Wright

Theses and Dissertations

This thesis presents a simulation of an LFM pulse-Doppler radar for surface-to-air applications and compares the performance of multiple CFAR detectors in processing the resulting range-Doppler maps. Each CFAR detector is reviewed and simulated. Their effectiveness in reducing target masking is analyzed. In addition, a new CFAR detector, the RDWT-CA-CFAR detector, is developed that uses the CDF 5/3 wavelet to decompose the range-data of the range-Doppler map along the range dimension and filter the target data from the reference cells, as a means to reduce or eliminate target masking. The QccPack library is used to perform RDWT functions. It is …

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African American Males' Identification Of Factors That Contributed To Their Community College Persistence, Ulissa Byshelle Coburn Dec 2017

African American Males' Identification Of Factors That Contributed To Their Community College Persistence, Ulissa Byshelle Coburn

Theses and Dissertations

In spite of an expanding enrollment of African American males in community colleges in the United States, the early departure of this minority group is one of concern. The purpose of this qualitative study was to explore African American males’ identification of the factors that contributed to their persistence at community colleges. Data were collected through structured interviews with 7 African American male community college graduates who were enrolled at a 4-year university when the study was conducted. Data were analyzed through by coding and categorizing in order to determine themes. Social integration and social cognitive models were used to …

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An Investigative Study Toward The Development Of A Crosslinked Porcine Xenograft Meniscus Total Replacement, Patrick Ehren Barton Dec 2017

An Investigative Study Toward The Development Of A Crosslinked Porcine Xenograft Meniscus Total Replacement, Patrick Ehren Barton

Theses and Dissertations

Meniscus damage is very common and eventually leads to the deterioration of the entire knee joint. The goal of this study was to provide evidence that supports a proof of concept for a decellularized porcine meniscal xenograft to be used as a treatment method for meniscal injury as a partial or full meniscus transplant. This research adapted an antigen removal protocol for articular cartilage to produce decellularized xenografts in 48% of the time and with no significant difference in DNA content as other current methods. DNA and GAG content, and the compression moduli were significantly lower in the xenograft than …

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Authentic Leadership, Research Integrity, And Institutions Of Higher Learning: Why Focusing On Departmental Leadership Is Critical For Preserving The Sanctity Of Science, Katherine I. Echols Dec 2017

Authentic Leadership, Research Integrity, And Institutions Of Higher Learning: Why Focusing On Departmental Leadership Is Critical For Preserving The Sanctity Of Science, Katherine I. Echols

Theses and Dissertations

One of the most overlooked and complex problems that universities and colleges face nation-wide is how to reduce and eliminate research misconduct. Because of the confidential nature of allegations of research misconduct and the high rate of underreporting, administrators at scholarly institutions struggle with understanding the cause of such behavior. Without a clear picture of the prevalence of misconduct or the barriers to reporting, leaders at institutions of higher learning find themselves at a disadvantage when dealing with these problems. This uncertainty coupled with a growing regulatory emphasis from federal funding agencies, results in a reactionary approach while questionable practices …

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Toward A Molecular Mechanism Of Phase Separation In Disordered Elastin-Like Proteins, Yue Zhang Dec 2017

Toward A Molecular Mechanism Of Phase Separation In Disordered Elastin-Like Proteins, Yue Zhang

Theses and Dissertations

Since the last decade, an increasing number of proteins have been shown to be capable of undergoing reversible liquid-liquid phase separation (LLPS) in response to an external stimulus, and the resulting protein-rich phase (coacervate) is considered as one of the main components of membrane-less organelles. Most of these proteins are intrinsically disordered proteins (IDPs) or contain intrinsically disordered regions. More importantly, LLPS often plays an important role in cellular signaling and development of cells and tissues. However, the molecular mechanisms underlying LLPS of proteins remain poorly understood. Elastin-like proteins (ELPs), a class of IDPs derived from the hydrophobic domains of …

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Production Of Tempo-Oxidized Cellulose Nanofibers From Cotton Stalks And Its Utilization In Different Industrial Applications, Bhawna Soni Dec 2017

Production Of Tempo-Oxidized Cellulose Nanofibers From Cotton Stalks And Its Utilization In Different Industrial Applications, Bhawna Soni

Theses and Dissertations

Cellulose nanofibers (CNFs) have established widespread attention in various industries with their potential applications. Production of CNFs from agricultural post harvesting wastes has several cost-effective and eco-friendly benefits. The objective of this research was to prepare four different types of CNFs from cotton stalks by different chemical treatments followed by ultra-sonication. CNFs via untreated bleached pulp, sulfuric acid hydrolysis, and TEMPO [(2,2,6,6-tetramethylpiperidin-1-yl) oxy radical]-mediated oxidation process were produced. Physical and chemical properties of these CNFs were investigated by morphological (FE-SEM, AFM), structural (FTIR), and thermal gravimetric analysis (TGA). Developed TEMPO-oxidized cellulose nanofibers (TEMPO-CNFs) were brighter and higher in yields ( …

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Classification And Significance Assessments Of Occupations On The Ackerman Unit Of The Tombigbee National Forest, Mississippi, Mary A. Madden Dec 2017

Classification And Significance Assessments Of Occupations On The Ackerman Unit Of The Tombigbee National Forest, Mississippi, Mary A. Madden

Theses and Dissertations

The Ackerman Unit of the Tombigbee National Forest has served as the location of numerous archaeological investigations. Despite all of the work done, there is a question of whether a representative sample of the archaeological record has been saved and subsequently whether the reports and findings from the Ackerman Unit of the Tombigbee National Forest are legitimate and can be applied to a larger body or research at the regional, and even national scale. This thesis will evaluate whether a paradigmatic classification of occupations can be used to assess if a representative sample of the archaeological record has been saved, …

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Control Of Görtler Vortices In High-Speed Boundary Layers, Radwa Alaziz Dec 2017

Control Of Görtler Vortices In High-Speed Boundary Layers, Radwa Alaziz

Theses and Dissertations

Görtler vortices develop in boundary layer flows over concave surfaces due to the imbalance between centrifugal forces and the wall-normal pressure gradient. These vortices can be efficient precursors to transition in boundary layers exposed to free-stream disturbance or surface non-uniformities, because they can alter the mean flow causing the laminar flow to breakdown into turbulence. In this thesis, a control technique aimed at reducing the energy associated with Görtler vortices that develop in supersonic boundary layers is introduced and tested. The control algorithm is based on distributed blowing and suction, with sensors placed either in the flow or at the …

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"A Grave Subject:" Hollywood Cemetery And The Ideology Of Death In Mid-Nineteenth Century America, Kelli Brooke Nelson Dec 2017

"A Grave Subject:" Hollywood Cemetery And The Ideology Of Death In Mid-Nineteenth Century America, Kelli Brooke Nelson

Theses and Dissertations

During the nineteenth century, Americans began to develop a new relationship with death. Urbanites were less confronted with the constant presence of the dead and dying than they had in the past. A new trend in cemeteries also developed as a result. The Rural Cemetery Movement promoted the idea that the dead should be buried amongst a natural setting that was pleasing and calming to visitors. The first few initial cemeteries were an immediate success, but this was not the case in Richmond, Virginia. Although the developers had grand ideas about their cemetery project, Richmonders opposed the cemetery in the …

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Assessment Of Nitinol-Based Arch Wedge Support Through Finite Element Analysis, Tyler Nicholas Stranburg Dec 2017

Assessment Of Nitinol-Based Arch Wedge Support Through Finite Element Analysis, Tyler Nicholas Stranburg

Theses and Dissertations

This study proposes a nitinol-based thin-walled arch wedge support (AWS) and validated its performance in shock absorbing by using finite element analysis (FEA) method. Five human movements, two boundary conditions, and three thicknesses were implemented in FEA models to systematically reveal how those parameters and factors affect the response of the AWS. Due to the lack of data, the FEA models were meshed with elements of different sizes and used for simulations until the results converged. The simulation results showed that the thin-walled nitinol AWS with the selected thicknesses can withstand different human movements under both boundary conditions. In another …

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Capturing Aggregate And Binder Interaction Effects On Aging Via Mixture Testing For Single Aggregate Source Asphalt Mixtures, Bradley Scott Hansen Dec 2017

Capturing Aggregate And Binder Interaction Effects On Aging Via Mixture Testing For Single Aggregate Source Asphalt Mixtures, Bradley Scott Hansen

Theses and Dissertations

This thesis compares asphalt mixture properties before and after one year of field aging. Simple mixtures, one aggregate source for coarse, fine, and dust proportions, were developed and tested using four mixture tests to isolate asphalt-aggregate interaction. The results found asphalt-aggregate interaction effects and mixing temperature had considerable effects on mixture aging after 1 year. Differences in mass loss, rut depth, and indirect tensile strength that existed before aging became more pronounced after aging. This thesis’ results agree with the literature reviewed and generates new knowledge for mixture design and materials selection considerations for improved pavement performance. It is recommended …

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"Deep" South: Mammoth Cave, Kentucky, And Environmental Knowledge, 1800-1974, Alyssa Diane Warrick Dec 2017

"Deep" South: Mammoth Cave, Kentucky, And Environmental Knowledge, 1800-1974, Alyssa Diane Warrick

Theses and Dissertations

Mammoth Cave in Kentucky is the longest known cave in the world. This dissertation examines the history of how scientists and non-scientists alike contributed to a growing body of knowledge about Mammoth Cave and how that knowledge in turn affected land use decisions in the surrounding neighborhood. During the nineteenth century visitors traveled through Mammoth Cave along with their guides, gaining knowledge of the cave by using their senses and spreading that knowledge through travel narratives. After the Civil War, cave guides, now free men who chose to stay in the neighborhood, used the cave as a way to build …

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Evaluating The Validity Of Latency Effects In Robotics Simulation, Leif T. Jensen Dec 2017

Evaluating The Validity Of Latency Effects In Robotics Simulation, Leif T. Jensen

Theses and Dissertations

Latency is a common issue found in robotics teleoperation that is not currently addressed in simulation. This study examined the effects of latency on operator performance for a robot teleoperation navigation task. Operators used a Logitech gamepad controller to teleoperate a robot through both a simulated environment and real-world environment. Both environments had the same dimensions and provided a path with obstacles the participant had to navigate. Participants performed this navigation task under three latency conditions, zero, low and high. Completion time, number of collisions, NASA-TLX, System Usability Survey, and User Experience survey were collected and participant performance compared for …

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Dry Reforming Of Methane To Produce Syngas Over Ni-Based Bimodal Pore Catalysts, Zhenghong Bao Dec 2017

Dry Reforming Of Methane To Produce Syngas Over Ni-Based Bimodal Pore Catalysts, Zhenghong Bao

Theses and Dissertations

Dry reforming of methane is an important reaction to generate syngas from two greenhouse gases. The syngas can be used in Fishcher-Tropsch synthesis to produce valueded chemicals. Chapter I reviews the catalytic conversion of methane and carbon dioxide to syngas, including DRM reaction chemistry, catalysts used in this process, catalyst deactivation, and the kinetics of DRM reaction. Chapter II discusses the development of bimodal pore NiCeMgAl catalysts for DRM reaction. Bimodal pore NiCeMgAl catalysts were synthesized via the refluxed co-precipitation method and systematically investigated the influence of active metal loading, calcination temperature, reduction temperature and gas hourly space velocity (GHSV) …

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