Physical Sciences and Mathematics Commons^™

Visuohaptic Simulation Of A Borescope For Aircraft Engine Inspection, Deepak Vembar

All Dissertations

Consisting of a long, fiber optic probe containing a small CCD camera controlled by hand-held articulation interface, a video borescope is used for remote visual inspection of hard to reach components in an aircraft. The knowledge and psychomotor skills, specifically the hand-eye coordination, required for effective inspection are hard to acquire through limited exposure to the borescope in aviation maintenance schools. Inexperienced aircraft maintenance technicians gain proficiency through repeated hands-on learning in the workplace along a steep learning curve while transitioning from the classroom to the workforce.
Using an iterative process combined with focused user evaluations, this dissertation details the …

Field Evaluation Of The Immunocontraceptive Gonacontm In Reducing Eastern Gray Squirrel Fecundity In Urban Areas, Murali Pai

All Dissertations

The purpose of this study was to evaluate the immunocontraceptive GonaCon^TM in reducing fecundity in Eastern gray squirrel (EGS) (Sciurus carolinensis) in urban areas. Using a modified box trap design, 317 EGS were captured during four trapping sessions on a 5.66 ha site on Clemson University's main campus. EGS were handled using a restraint cone and sexed, weighed, ear-tagged and implanted with a microchip at the nape of the neck on all 'original' captures and later identified in subsequent captures as 'recaptures.' Blood samples and morphometric data were obtained on EGS before the immunocontraceptive GonaCon^TM was administered by …

Synthesis, Modification Of Mesoporous Carbons And Their Application In Polymer Electrolyte Membrane Fuel Cells, Bing Liu

All Dissertations

Mesoporous carbon materials of carbon xerogel (CX) and silica-templated carbon (MC) were synthesized and explored as catalyst supports alternative to the most-commonly-used carbon black (CB) support, for polymer-electrolyte-membrane fuel cell (PEMFC) application. Pt catalyst was loaded on these carbons and electrodes were fabricated from them. These Pt-loaded carbon supports were characterized with XRD, TEM, ex-situ and in-situ cyclic voltammetry, etc. The fabricated electrodes were evaluated in single-cell testing in comparison with commercial CB-supported Pt catalyst fabricated electrodes. The experimental results showed that CX-supported Pt catalyst had close or better performance than that of CB-supported Pt, possibly due to CX's 3-D …

Examining The Dynamics Of Managing Information Systems Development Projects: A Control Loss Perspective, Ravi Narayanaswamy

All Dissertations

The failure rate of information systems development (ISD) projects continues to pose a big challenge for organizations. The success rate of ISD projects is less then forty percent. Factors such as disagreements and miscommunications among project manager and team members, poor monitoring and intermediary problems contribute to project failure.
Agency theory and leader member exchange (LMX) theories offer potential explanations for project failure. In particular, three monitoring strategies - control strategy, decision rights, and influence tactics were found to be effective in promoting project success. LMX theorists suggest that achieving congruence between the manager and subordinate regarding each other actions …

Branchings And Time Evolution Of Reaction Networks, Changyuan Wang

All Dissertations

In this thesis I analyze flows in reaction networks in terms of branchings
in a digraph. If the coupled differential equations governing the rate
of change of probabilities X of a state or species are finite-differenced in time, a matrix equation (I + Adt)X(t+dt) = X(t) results, where X(t) is a vector giving the probabilities at time t and X(t+dt) is a vector giving the probabilities at time t + dt. I demonstrate that the matrix (I + Adt) may be written as the product of an incidence matrix and a weight matrix for a directed graph (digraph) representing the …

Observations Of Badgers Preying On Black-Tailed Prairie Dogs, Daniel S. Licht

The Prairie Naturalist

American badgers (Taxidea taxus) often visit black-tailed prairie dog (Cynomys ludovicianus) colonies, most likely in search of prey (Lomolino and Smith 2004, Shaughnessy and Cifelli 2004). Badgers are well suited to hunting fossorial prey such as prairie dogs by excavating burrows and capturing individuals belowground (Lindzey 2003). However, the ecological literature is sparse regarding details of how badgers hunt and capture prairie dogs underground. Eads and Biggins (2008) documented three occurrences of a badger excavating prairie dogs. That badger (apparently the same individual) had a den within the prairie dog town where captures occurred. This note …

Mortality Of Cranes (Gruidae) Associated With Powerlines Over A Major Roost On The Platte River, Nebraska, Gregory D. Wright, Timothy J. Smith, Robert K. Murphy, Jeffery T. Runge, Robert R. Harms

The Prairie Naturalist

Two 69-kilovolt powerlines spanning the Platte River in south central Nebraska are suspected to cause substantial mortality to sandhill cranes (Grus canadensis) and pose a threat to endangered whooping cranes (G. americana) that roost overnight on the river during spring and fall migrations. Most studies of crane collisions with powerlines in the region have focused on counts of carcasses away from night roosts on the river and none have accounted for potential biases in detecting carcasses. We found 61 carcasses of sandhill cranes below over-river segments of the two powerlines during 4 March to 7 April …

Regularity Of Non-Characteristic Minimal Graphs In The Heisenberg Group ℍ1, Luca Capogna, Giovanna Citti, Maria Manfredini

Mathematics Sciences: Faculty Publications

Minimal surfaces in the sub-Riemannian Heisenberg group can be constructed by means of a Riemannian approximation scheme, as limit of Riemannian minimal surfaces. We study the regularity of Lipschitz, non-characteristic minimal surfaces which arise as such limits. Our main results are apriori estimates on the solutions of the approximating Riemannian PDE and the ensuing C∞ regularity of the sub-Riemannian minimal surface along its Legendrian foliation.

Statistical Analysis Of Linear Analog Circuits Using Gaussian Message Passing In Factor Graphs, Miti Phadnis

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This thesis introduces a novel application of factor graphs to the domain of analog circuits. It proposes a technique of leveraging factor graphs for performing statistical yield analysis of analog circuits that is much faster than the standard Monte Carlo/Simulation Program With Integrated Circuit Emphasis (SPICE) simulation techniques. We have designed a tool chain to model an analog circuit and its corresponding factor graph and then use a Gaussian message passing approach along the edges of the graph for yield calculation. The tool is also capable of estimating unknown parameters of the circuit given known output statistics through backward message …

Geometry And Electronic Structure Of Doped Clusters Via The Coalescence Kick Method, Boris Averkiev

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Developing chemical bonding models in clusters is one of the most challenging tasks of modern theoretical chemistry. There are two reasons for this. The first one is that clusters are relatively new objects in chemistry and have been extensively studied since the middle of the 20th century. The second reason is that clusters require high-level quantum-chemical calculations; while for many classical molecules their geometry and properties can be reasonably predicted by simpler methods.

The aim of this dissertation was to study doped clusters and explain their chemical bonding. The research was focused on three classes of compounds: aluminum clusters doped …

Reactivity Of Phenyldi(2-Thienyl)Phosphine Towards Group 7 Metal Carbonyls: Carbon–Phosphorus Bond Activation, Shishir Ghosh, Alok K. Das, Noorjahan Begum, Daniel T. Haworth, Sergey V. Lindeman, James R. Gardinier, Tasneem A. Siddiquee, Dennis W. Bennett, Ebbe Nordlander, Graeme Hogarth, Shariff E. Kabir

Chemistry Faculty Research and Publications

Addition of phenyldi(2-thienyl)phosphine (PPhTh₂) to [Re₂(CO)_10−n(NCMe)_n] (n = 1, 2) affords the substitution products [Re₂(CO)_10−n(PhPTh₂)_n] (1, 2) together with small amounts of fac-[ClRe(CO)₃(PPhTh₂)₂] (3) (n = 2). Reaction of [Re₂(CO)₁₀] with PPhTh₂in refluxing xylene affords a mixture which includes 2, [Re₂(CO)₇(PPhTh₂)(μ-PPhTh)(μ-H)] (4), [Re₂(CO)₇(PPhTh₂)(μ-PPhTh)(μ-η¹,κ¹(S)-C₄H₃S)] (5) and …

Alternative Sampling And Analysis Methods For Digital Soil Mapping In Southwestern Utah, Colby W. Brungard

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Digital soil mapping (DSM) relies on quantitative relationships between easily measured environmental covariates and field and laboratory data. We applied innovative sampling and inference techniques to predict the distribution of soil properties, soil attributes, taxonomic classes, and dominant vegetation across a 30,000-ha complex Great Basin landscape in southwestern Utah. This arid rangeland was characterized by rugged topography, diverse vegetation, and intricate geology. Environmental covariates calculated from digital elevation models (DEM) and spectral satellite data were used to represent factors controlling soil development and distribution. We investigated optimal sample size and sampled the environmental covariates using conditioned Latin Hypercube Sampling (cLHS). …

Costs Of Implementing Collective Action And Capacity Building Among Pastoralists In Southern Ethiopia, D. Layne Coppock, Seyoum Tezera, Solomon Desta

Environment and Society Faculty Publications

Since 2000, the PARIMA project has implemented risk-management activities among semi-settled pastoralists in southern Ethiopia. The goal has been to improve human welfare via collective action and capacity building. Outcomes include progress in income generation, asset conservation, and livelihood diversification. Fifty-nine collective-action groups were created. Dominated by women, they included over 2,000 founding members and groups have recently merged to form 37 cooperatives, consistent with government policy. Creating sustainable impacts via collective action and capacity building requires many inputs. Taking raw, illiterate volunteers and transforming them into sustainable groups took up to three years, on average. Costs of implementing this …

Some New Problems In Changepoint Analysis, Jonathan Woody

All Dissertations

Climatological studies have often neglected changepoint effects when modeling
various physical phenomena. Here, changepoints are plausible whenever a station location moves or its instruments are changed. There is frequently meta-data to
perform sound statistical inferences that account for changepoint
information. This dissertation focuses on two such problems in changepoint analysis.
The first problem we investigate involves assessing trends
in daily snow depth series. Here, we introduce a stochastic storage model. The model allows for seasonal features, which permits the
analysis of daily data. Changepoint times are shown to greatly influence estimated trends in one snow depth series and are accounted …

On The Testing And Estimation Of High-Dimensional Covariance Matrices, Thomas Fisher

All Dissertations

Many applications of modern science involve a large number of parameters. In
many cases, the number of parameters, p, exceeds the number of observations,
N. Classical multivariate statistics are based on the assumption that the
number of parameters is fixed and the number of observations is large. Many of
the classical techniques perform poorly, or are degenerate, in high-dimensional
situations.
In this work, we discuss and develop statistical methods for inference of
data in which the number of parameters exceeds the number of observations.
Specifically we look at the problems of hypothesis testing regarding and the
estimation of the covariance …

Metal Oxide And Mercuric Sulfide Nanoparticles Synthesis And Characterization, Xin Xu

All Dissertations

Increasing applications of nanoparticles (NPs), such as metal oxide and mercuric sulfide NPs, lead to heightened environmental concern. Challenges to the study of natural and engineered NPs include the physical and chemical characterizations.
Commercially available and laboratory-synthesized metal based NPs, iron oxide (Fe2O3), copper oxide (CuO), titanium dioxide (TiO2), zinc oxide (ZnO) and mercuric sulfide (HgS) were studied by comprehensive characterizations methods. The general synthesis process was modified sol-gel method. The size and morphology of NPs could be influenced by temperature, sonication, calcination, precursor concentration, pH and types of reaction media. In the synthesis of nZnO in ethanol, the essential …

Decoding Of Multipoint Algebraic Geometry Codes Via Lists, Nathan Drake

All Dissertations

Algebraic geometry codes have been studied greatly since their introduction by Goppa . Early study had focused on algebraic geometry codes CL(D;G) where G was taken to be a multiple of a single point. However, it has been shown that if we allow G to be supported by more points, then the associated code may have better parameters. We call such a code a multipoint code and if G is supported by m points, then we call it an m-point code. In this dissertation, we wish to develop a decoding algorithm for multipoint codes. We show how we can embed …

Atom Scattering From Metals, William Hayes

All Dissertations

In the initial portion of this dissertation studies of Ar
scattering from Ru(0001) at thermal and hyperthermal energies are
compared to calculations with classical scattering theory. These
data exhibited a number of characteristics that are unusual in
comparison to other systems for which atomic beam experiments have
been carried out under similar conditions. The measured energy
losses were unusually small. Some of the angular distributions
exhibited an anomalous shoulder feature in addition to a broad
peak near the specular direction and quantum mechanical
diffraction was observed under conditions for which it was not
expected. Many of the unusual features observed …

Characterization Of Escherichia Coli Related To Construction Site Sediment Basins, Calvin Sawyer

All Dissertations

Large construction sites can have significant temporary and permanent impacts on the physical landscape. Excess sediment is frequently deposited into nearby surface waters, altering benthic habitat, reducing water clarity and transporting other pollutants such as enteric bacteria. To capture eroded soil and attenuate storm discharge peaks, many permitted construction projects larger than 10 acres in South Carolina require the installation of a sediment basin. Sediment-laden runoff is routed to a newly excavated impoundment, where larger particles settle out of suspension. Thus an entirely new hydrologic feature designed to concentrate eroded sediment and water is introduced into the landscape.
Eight construction …

Synthesis And Characterization Of Metallic, Core-Shell And Composite Nanoparticles, Amar Kumbhar

All Dissertations

ABSTRACT
Silver nanoparticles exhibit size, shape and the surrounding dielectric medium dependent optical properties (scattering and absorption) in the visible spectral region. These optical properties can be explained in terms of the collective oscillation of the 'free conduction band electrons' or 'surface plasmons' induced by an external electromagnetic field. Dipole and Quadrupole Plasmon resonances have been observed for silver particles less than 100nm in diameter prepared using various synthetic techniques. However higher order resonances have been elusive due to lack of experimental techniques to prepare colloidal solutions of large silver nanoparticles in the size range above 100nm. Controlled hydrogen reduction …

Development Of A Fluorescent Probe For Determination Of Water Transport In Subcellular Organelles, Adriana Chaurra-Arboleda

All Dissertations

Water transport has been widely studied in a variety of cells and isolated membranes. However, the intrinsic complexity related with the study of intracellular processes has delayed the development of an analytical technique for the study of water transport in subcellular compartments of living cells. This study represents the development and application of a ratiometric fluorescent probe to study water transport in endocytic organelles of intact living cells. The probe is based on the use of a D₂O-sensitive fluorophore, Lucifer yellow dextran (LY-dex), together with a D₂O-insensitive fluorophore, Alexa fluor 546 dextran (AF546-dex), used as an …

An Approach Designed For Reginal Prospective Human Health And Ecological Risk Assessment And Its Application To Mercury Risks From A Coal-Fired Power Plant, Pathratipa Sansayavichai

All Dissertations

A large and/or long-term released source of a toxic chemical(s) can cause adverse effects to humans and non–human species inhabiting all over the region. The overall goal of this dissertation was to improve practices in risk assessment concerning a regional risk posed by a prospective source. A generic conceptual framework for performing regional prospective human health and ecological risk assessment was developed. The formulation of a priori considerations was used to identify the possible sources of uncertainties in the prospective risk assessment. Physiologically based pharmacokinetic (PBPK) modeling was utilized to reduce uncertainty in a toxicologically safe dose used in risk …

Polymeric Carbon Nanocomposites - Preparation, Characterization, And Properties, Lucia Veca

All Dissertations

Excellent thermal properties of carbon nanomaterials such as carbon nanotubes and newly discovered graphene make them the filler of choice for the development of thermal management materials. Graphene has been viewed as “ unrolled single-walled carbon nanotube and as a wonder material with many superlatives to its name ” thus there is an excessive interest in developing new synthetic routes towards large scale production of high quality graphene nanosheets.
In this dissertation, we report different methods that could further exfoliate the commercially available expanded graphite to nanometer sized carbon structures, “carbon nanosheets ”, for their use in highly thermal conductive …

Decolorization Of Anthraquinone Vat Blue 4 By The Free Cells Of An Autochthonous Bacterium, Bacillus Subtilis, Rajee Olaganathan, Jamila Patterson

Publications

Uncontaminated soil, Vat Blue 4 contaminated soil and Vat Blue 4 effluent were screened for heterotrophic bacterial population and the bacterial density were found to be 19.3 £ 104 Colony Forming Units (CFU)/gm, 5.5 £ 104 CFU/gm and 1.1 £ 104 CFU/ml respectively. Student’s ‘t’ test analysis affirmed that significant variation prevailed between the three set of ‘t’ tests conducted (P , 0.001 to 0.002). The heterotrophic bacterial population of dye contaminated soil comprised of 32.5% of Pseudomonas spp. followed by 27.5% of Bacillus spp., 15.0% of Aeromonas spp., 12.5% of Micrococcus spp. and 12.5% of Achromobacter spp. The optimum …

A Graph Theoretic Summation Of The Cubes Of The First N Integers, Joseph Demaio, Andy Lightcap

Faculty Articles

In this Math Bite we provide a combinatorial proof of the sum of the cubes of the first n integers by counting edges in complete bipartite graphs.

Nutrient Cycles And Marine Microbes In A Co2-Enriched Ocean, David A. Hutchins, Margaret R. Mulholland, Feixue Fu

OES Faculty Publications

The ocean carbon cycle is tightly linked with the cycles of the major nutrient elements nitrogen, phosphorus, and silicon. It is therefore likely that enrichment of the ocean with anthropogenic CO2 and attendant acidification will have large consequences for marine nutrient biogeochemistry, and for the microbes that mediate many key nutrient transformations. The best available evidence suggests that the nitrogen cycle may respond strongly to higher CO2 through increases in global N2 fixation and possibly denitrification, as well as potential decreases in nitrification. These trends could cause nitrification to become a nitrogen cycle "bottleneck," by increasing the flux of N2 …

Eleven Years Of Parima Activities In North-Central Kenya: Impacts On Egerton University And Neighboring Communities, D. Layne Coppock, Abdillahi Aboud, Mark Mutinda, Stellamaris Muthoka

Environment and Society Faculty Publications

The PARIMA project was created to improve the well-being of pastoralists and agro-pastoralists in northern Kenya and southern Ethiopia via risk-management research, training, and outreach. The project began to collaborate with Egerton University’s Department of Natural Resources in 1998 and many joint activities were undertaken over the next 11 years. Among them were regional household research on pastoral risks and their management, a training program for Egerton teaching staff to obtain post-graduate degrees, facilitation of Egerton faculty and staff to attend professional meetings, and provision of computer hardware and software that led to the creation of a GIS teaching and …

Simple Cooling Method Improves The Quality Of Marketed Camel Milk In Northern Kenya, D. Layne Coppock, A. O. Adongo, F. Wayua, I. J. Sagalla, H. K. Walaga, C. Amboga

Environment and Society Faculty Publications

Milk marketing is important for many pastoralists to generate income, especially poor households with little else to sell. Milk is accumulated at pastoral settlements and transported to local markets on foot, by pack animals, or in vehicles. Despite challenges of heat and long-distance travel, pastoralists or traders do not attempt to cool marketed milk and possibly reduce risk of spoilage. Milk spoilage is an important problem that limits urban consumer demand. Our research objective was to determine effects of water-soaked hemp (burlap), wrapped around plastic jerry cans, on reducing milk temperature and enhancing quality of marketed camel milk, a key …

Can Pastoral Linkages To Livestock Markets Be Sustained In Southern Ethiopia?, D. Layne Coppock, Getachew Gebru, Solomon Desta, Seyoum Tezera, Zewdu Edea

Environment and Society Faculty Publications

The PARIMA project has facilitated collective action, empowerment of women, and increased involvement in livestock marketing among pastoralists on the Borana Plateau since 2001. Fifty-nine collective-action groups formed by PARIMA and her partners have been recently merged into market-oriented cooperatives, consistent with government policy. We used focus groups and participatory appraisals to assess the extent that market linkages have been sustained since previously reported in 2006. The markets have been growing, but are volatile. Members report they need access to early warning and livestock market-information systems, as well as more capital, to promote trade. Export firms have imposed added conditions …

Evaluation Of Windows Servers Security Under Icmp And Tcp Denial Of Service Attacks, Hari Krishnea Vallalacheruvu

Theses and Dissertations - UTB/UTPA

Securing server from Distributed denial of service (DDoS) attacks is a challenging task for network operators. DDOS attacks are known to reduce the performance of web based applications and reduce the number of legitimate client connections. In this thesis, we evaluate performance of a Windows server 2003 under these attacks. In this thesis, we also evaluate and compare effectiveness of three different protection mechanisms, namely SYN Cache, SYN Cookie and SYN proxy protection methods, to protect against TCP SYN DDoS attacks. It is found that the SYN attack protection at the server is more effective at lower loads of SYN …