Physical Sciences and Mathematics Commons^™

The Electrochemical Deposition Of Samarium And Europium Dissolved In Ionic Liquid Solvent, Bea Martinez

UNLV Theses, Dissertations, Professional Papers, and Capstones

Rare-earth elements include the lanthanide series in the periodic table with the addition of scandium and yttrium. China produces approximately 95% of the world’s rare-earths supply and is the largest consumer of the world’s rare earth supply. Domestic production of rare-earth metals is a priority in the US. The domestic demand for rare-earth elements is largely based on their use in electronic devices, catalytic converters, and more importantly defense applications. Therefore, China’s monopoly of rare-earth elements is viewed as a threat to national security. Although capital investments have resulted in an increase in domestic mining and refining of rare-earth materials, …

Surface And Interface Characterization Of Solution-Processed Metal Oxides And Pedot:Pss Using Photoelectron Spectroscopy, Lynette M. Kogler

UNLV Theses, Dissertations, Professional Papers, and Capstones

Solution-processed materials are appealing for use in printable electronics as a means to lower production costs, but precise control of the process is crucial for achieving the desired properties in the final materials and their interfaces. Electronic interface properties depend on both the involved materials and their fabrication processes, impacting the development and commercialization of these materials. Analyzing the chemical and electronic structure of these materials, particularly at the surfaces and interfaces, is important not only for insuring that the materials have the desired properties, but also for understanding the effects of the fabrication process and how to modify properties …

Miocene-Pliocene(?) Folds, Normal Faults And The Left-Lateral Buckhorn Fault With Regional Implications, Pahranagat Shear Zone, Nevada, Thomas Godfrey Price

UNLV Theses, Dissertations, Professional Papers, and Capstones

Strike-slip faults play an important role in the development and evolution of extensional regimes including in the intraplate extension in the Basin and Range province. The Basin and Range province is divided into the Northwestern, Northern, Central and Southern Basin and

Range subprovinces. The boundary zone between the Northern and Central subprovinces is marked by several left-lateral fault zones, including the Pahranagat Shear Zone (PSZ), Caliente-Enterprise Zone and Rock Valley Fault Zone. The PSZ has a close spatial and kinematic relationship with the left-lateral Caliente-Enterprise Zone, which lies to the NE, and a slightly more distal relationship to the left-lateral …

Phase Equilibria, Compressibility, And Thermal Analysis Of Bastnaesite-(La), Richard Lee Rowland

UNLV Theses, Dissertations, Professional Papers, and Capstones

Understanding basic material properties of rare earth element (REE) bearing minerals such as the temperatures and pressures at which different phases are thermodynamically stable and how they respond to changes in temperature and pressure can assist in understanding how economically viable deposits might form, thereby potentially leading to the discovery of new deposits. Bastnaesite is the most common REE bearing mineral mined. The lanthanum-fluoride end member, bastnaesite-(La), was synthesized. Synthetic bastnaesite-(La) and lanthanum oxyfluoride was investigated using thermal analysis at ambient pressure and high temperature through the methods of thermogravimetric analysis, differential scanning calorimetry, and heated stage powder X-ray diffraction. …

The Role Of Pre-Existing Type 2 Diabetes Mellitus In Colorectal Cancer Stage And Survival In Elderly Americans: A Seer-Medicare Population-Based Study 2002-~2011, Sanae El Ibrahimi

UNLV Theses, Dissertations, Professional Papers, and Capstones

Diabetes is a common comorbid condition among colorectal cancer (CRC) patients, yet its effects in CRC outcomes, particularly stage at diagnosis, risk of death and variations by diabetes severity (complications vs no complications) and Hispanic ethnicity have not been adequately studied. The purpose of this study was to investigate the association between pre-existing T2DM and advanced stage at diagnosis in elderly patients with CRC; to examine whether diabetes is an independent predictor of poor survival from all-cause and CRC-specific mortality; to assess whether variations exist by diabetes severity and to analyze the outcomes for the Hispanic group.

The Surveillance Epidemiology …

A Test Driven Approach To Develop Web-Based Machine Learning Applications, Armin Esmaeilzadeh

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this thesis is to propose the design and architecture of a testable, scalable, and ef-cient web-based application that models and implements machine learning applications in cancer prediction. There are various components that form the architecture of our web-based application including server, database, programming language, web framework, and front-end design. There are also other factors associated with our application such as testability, scalability, performance, and design pattern. Our main focus in this thesis is on the testability of the system while consid- ering the importance of other factors as well.

The data set for our application is a …

Investigation Of Setting Time And Compressive Strength Of Ready-Mixed Concrete Blended With Returned Fresh Concrete, Negasi Niguse Gebremichael

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Center for Sustainable Transportation Infrastructure (CSTI), in its 2012 study, estimated that out of all the concrete leaving the plant, between 2% and 7% of concrete returns to the plant unused as a returned fresh concrete (RFC). Disposal of both the truck wash water and RFC is a growing concern for the industry. Most industry personnel contacted during the investigation, agree that reusing is superior to recycling of this substantial RFC economically and environmentally. This study will determine if the reuse of RFC in subsequent batches compromises the quality of newly blended concrete.

The effect of RFC on fresh …

Controlled Electrochemical Reduction Of Gold And Palladium Metal Precursors In Polyaniline, Nicole Goodwin

UNLV Theses, Dissertations, Professional Papers, and Capstones

Polyaniline (PANI) has been extensively studied due to its unique electrochemical properties. The conjugated polymer is conductive with high chemical stability below 100°C, mechanical strength, and large surface area. The applications of PANI have included chemical sensing, corrosion inhibition coatings, light emitting diode and as a substrate for metal composite catalysts. Both chemical and electrochemical methods have been developed and utilized in the synthesis of PANI/metal composites. The simultaneous reduction of aniline and metal precursor produces a composite of PANI encapsulated metal, reducing the active surface area available for catalysis. Alternatively, chemical reduction of the metal precursor into preformed PANI …

Average Cayley Genus For Groups With Two Generators Of Order Greater Than Two, Dawn Sturgeon

UNLV Theses, Dissertations, Professional Papers, and Capstones

Determining the orientable surfaces on which a particular graph may be imbedded is a basic problem in the area of topological graph theory. We look at groups modeled by Cayley graphs. Imbedding Cayley graphs with symmetry is done using Cayley maps. It is of interest to find the average Cayley genus for a particular group and generating set for the group. We consider the group known as the generalized quaternions with generating set ∆, where ∆ contains two generators with order greater than two. We find a formula for the average Cayley genus of the generalized quaternions. Moreover, we determine …

Lock-Free Self-Adjusting Binary Search Tree, Sachiko Sueki

UNLV Theses, Dissertations, Professional Papers, and Capstones

A binary search tree (BST) is a fundamental data structure for maintaining data in a way to allow fast search. As multi-core processors are widely used nowadays, such data structures require the ability to handle concurrent accesses to exploit the concurrent hardware. There are several algorithms on lock-based as well as lock-free BST with and without self-balancing. On the other hand, only a few reports can be found on lock-based self-adjusting BST. To the best of our knowledge, there are no algorithms for lock-free self-adjusting BST. Lock-free guarantees overall progress even if some processes fail, whereas lock-based algorithms fail to …

The Transformation Of American Federalism, 1848-1912, Lance Sorenson

UNLV Theses, Dissertations, Professional Papers, and Capstones

United States expansion following the Mexican-American War served as the catalyst for a reinvention of American Federalism. While much of the historiography traces the accretion of sovereign power in the national government to events caused by the divisions between northern states and southern states, there is an important and understudied East to West component of the process by which sovereign boundaries changed. The American West is a legal space where the hazily defined and capacious concept of federalism received fuller form and clearer definition. During the late nineteenth century and first few years of the twentieth century, the United States …

Emerging Infectious Disease And The Imperiled Relict Leopard Frog, Anthony Wayne Waddle

UNLV Theses, Dissertations, Professional Papers, and Capstones

The disease chytridiomycosis, caused by the aquatic fungal pathogen Batrachochytrium dendrobatidis (Bd), has emerged as a major contributing factor for worldwide amphibian declines. Although relatively recently described, the impacts from the disease this pathogen causes have been definitively tied to amphibian declines, including some that occurred decades ago. In some cases, declines of individual species occurred with little documentation and are thus poorly understood. The relict leopard frog (Rana onca = Lithobates onca) has experienced such a decline and by the latter part of the 20th century only occurred in two general areas in southern Nevada. Recent research has found …

Synthesis Of Actinide Materials For The Study Of Basic Actinide Science And Rapid Separation Of Fission Products, Jacquelyn M. Dorhout

UNLV Theses, Dissertations, Professional Papers, and Capstones

This dissertation covers several distinct projects relating to the fields of nuclear forensics and basic actinide science. Post-detonation nuclear forensics, in particular, the study of fission products resulting from a nuclear device to determine device attributes and information, often depends on the comparison of fission products to a library of known ratios. The expansion of this library is imperative as technology advances. Rapid separation of fission products from a target material, without the need to dissolve the target, is an important technique to develop to improve the library and provide a means to develop samples and standards for testing separations. …

The Impact Of Economic Recession On The Health Of Adult Nevadans, Ariana Goertz

UNLV Theses, Dissertations, Professional Papers, and Capstones

Recessions are generally considered to cause negative consequences, but recent studies have provided evidence that some health outcomes improve as the economy deteriorates. The relationship between economic downfalls and health is not straightforward; it is important to look at how health has been impacted in one of the areas hit hardest by the recession. Las Vegas, Nevada was previously considered recession-proof, seemingly unaffected by previous economic downturns exhibited by the rest of the country. However, during the Great Recession of 2007-2009, Las Vegas led the country in highest rates of unemployment and foreclosures. This was quite a collapse for a …

Using Two Simulation Tools To Teach Concepts In Introductory Astronomy: A Design-Based Research Approach, Pamela A. Maher

UNLV Theses, Dissertations, Professional Papers, and Capstones

Technology in college classrooms has gone from being an enhancement to the learning experience to being something expected by both instructors and students. This design-based research investigation takes technology one step further, putting the tools used to teach directly in the hands of students. The study examined the affordances and constraints of two simulation tools for use in introductory astronomy courses. The variety of experiences participants had using two tools; a virtual reality headset and fulldome immersive planetarium simulation, to manipulate a lunar surface flyby were identified using a multi-method research approach with N = 67 participants. Participants were recruited …

Synthesis And Electrochemical Characterization Of Pani/Ni And Pani/Au/Ni Composites, Morgan Emily Pacini

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this research is to show that the electrochemically controlled formation of monometallic and bimetallic catalysts in polyaniline (PANI) can directly influence the efficiency and reproducibility of the catalytic oxidation of methanol. PANI is a conductive polymer that provides a three-dimensional template for the metallic catalysts deposition at nitrogen sites. The controlled deposition of metallic species can be achieved using the normal oxidation/reduction cycles of PANI. The deposition of metallic species relies on anion precursors that are electrostatically bound by the polymer during the oxidation cycle. The precursor is reduced directly at the nitrogen sites in the polymer …

The Alma Early Science View Of Fuor/Exor Objects - V. Continuum Disc Masses And Sizes, Lucas Cieza, Dary Ruiz-Rodriguez, Sebastian Perez, Simon Casassus, Jonathan P. Williams, Alice Zurlo, David A. Principe, Antonio Hales, Jose L. Prieto, John J. Tobin, Zhaohuan Zhu, Sebastian Marino

Physics & Astronomy Faculty Research

Low-mass stars build a significant fraction of their total mass during short outbursts of enhanced accretion known as FUor and EXor outbursts. FUor objects are characterized by a sudden brightening of ∼5 mag at visible wavelengths within 1 yr and remain bright for decades. EXor objects have lower amplitude outbursts on shorter time-scales. Here we discuss a 1.3 mm Atacama Large Millimeter/submillimeter Array (ALMA) mini-survey of eight outbursting sources (three FUors, four EXors, and the borderline object V1647 Ori) in the Orion Molecular Cloud. While previous papers in this series discuss the remarkable molecular outflows observed in the three FUor …

U–Pb Dating Of Cave Spar: A New Shallow Crust Landscape Evolution Tool, D. D. Decker, V. J. Ployak, Y. Asmeron, Matthew Lachniet

Geoscience Faculty Research

In carbonate terranes, rocks types that provide apatite are not available to effectively use apatite fission track (AFT) or (U/Th)‐He chronometry (AHe). Here we suggest that calcite cave spar can be an effective chronometer and complimentary to AFT and AHe thermochronometers in carbonate regions such as our study area, the Guadalupe Mountains of southeastern New Mexico, and west Texas. Our measured depth of cave spar deposition is 500 ± 250 m beneath the regional water table, formed at temperatures of 40° to 80°C, indicating that these caves and their spar crystals form near the supercritical CO2‐subcritical CO2 boundary where we …

Thermotropic Liquid-Crystalline Properties Of Extended Viologen Bis(Triflimide) Salts, Pradip K. Bhowmik, Shane T. Killarney, Jessa Rose A. Li, Jung Jae Koh, Haesook Han, Lewis Sharpnack, Deña M. Agra-Kooijman, Michael R. Fisch, Satyendra Kumar

Chemistry and Biochemistry Faculty Research

A series of extended, symmetric viologen triflimides were synthesised by the metathesis reaction of lithium triflimide with the respective viologen tosyalates in methanol. Their chemical structures were characterised by Fourier Transform Infrared, 1H and 13C Nuclear Magnetic Resonance spectroscopy and elemental analysis. Their thermotropic liquid-crystalline (LC) properties were examined by a number of experimental techniques including differential scanning calorimetry, thermogravimetric analysis, polarising optical microscopy and variable temperature X-ray diffraction. The viologen salts containing alkyl chain of two carbon and three carbon atoms were relatively low melting salts. Those of alkyl chains of four carbon and five carbon atoms formed ionic …

Hyperaccreting Black Hole As Gamma-Ray Burst Central Engine. Ii. Temporal Evolution Of The Central Engine Parameters During The Prompt And Afterglow Phases, Wei-Hua Lei, Bing Zhang, Xue-Feng Wu, En-Wei Liang

Physics & Astronomy Faculty Research

A hyperaccreting stellar-mass black hole (BH) has been proposed as the candidate central engine of gamma-ray bursts (GRBs). The rich observations of GRBs by Fermi and Swiftmake it possible to constrain the central engine model by comparing the model predictions against data. This paper is dedicated to studying the temporal evolution of the central engine parameters for both the prompt emission and afterglow phases. We consider two jet-launching mechanisms, i.e., annihilations and the Blandford–Znajek (BZ) process, and obtain analytical solutions to these two models. We then investigate the BH central engine parameters, such as the jet power, the dimensionless entropy …

How Do Stars Gain Their Mass? A Jcmt/Scuba-2 Transient Survey Of Protostars In Nearby Star-Forming Regions, Gregory J. Herczeg, Doug Johnstone, Steve Mairs, Jennifer Hatchell, Jeong-Eun Lee, Geoffrey C. Bower, Huei-Ru Vivien Chen, Yuri Aikawa, Hyunju Yoo, Sung-Ju Kang, Miju Kang, Wen-Ping Chen, Jonathan P. Williams, Jaehan Bae, Michael M. Dunham, Eduard I. Vorobyov, Zhaohuan Zhu, Ramprasad Rao, Helen Kirk, Satoko Takahashi, Oscar Morata, Kevin Lacaille, James Lane, Andy Pon, Aleks Scholz, Manash R. Samal, Graham S. Bell, Sarah Graves, E'Lisa M. Lee, Harriet Parsons, Yuxin He

Physics & Astronomy Faculty Research

Most protostars have luminosities that are fainter than expected from steady accretion over the protostellar lifetime. The solution to this problem may lie in episodic mass accretion—prolonged periods of very low accretion punctuated by short bursts of rapid accretion. However, the timescale and amplitude for variability at the protostellar phase is almost entirely unconstrained…See full text for full abstract.

Environmental Effects On Drosophila Brain Development And Learning, Xia Wang, Amei Amei, J. Steven De Belle, Stephen P. Roberts

Mathematical Sciences Faculty Research

Brain development and behavior are sensitive to a variety of environmental influences including social interactions and physicochemical stressors. Sensory input in situ is a mosaic of both enrichment and stress, yet little is known about how multiple environmental factors interact to affect brain anatomical structures, circuits and cognitive function. In this study, we addressed these issues by testing the individual and combined effects of sub-adult thermal stress, larval density and early-adult living spatial enrichment on brain anatomy and olfactory associative learning in adult Drosophila melanogaster. In response to heat stress, the mushroom bodies (MBs) were the most volumetrically impaired among …

A Comparison Of Outdoor Bioaerosol And Particulate Measurements In Las Vegas, Tanviben Yogeshkumar Patel

UNLV Theses, Dissertations, Professional Papers, and Capstones

The urbanization of the Las Vegas Valley has turned the desert into a green oasis by introducing many non-native plant species, some of which are allergenic. Outdoor bioaerosols consist of microorganisms, pollen, spores, and other agents that could cause infections or affect the health of humans. Studies have suggested that exposure to bioaerosols through inhalation can lead to various human health risks. Typically, one monitoring station is established per city to obtain pollen and mold counts for an entire metropolitan area, and the site may not be representative of community exposures. The objective of this study was to measure and …

Instrumentation And Measurement Of Thermoelectric And Structural Properties Of Binary Chalcogenides And Half-Heusler Alloys At Extreme Conditions Using A Paris-Edinburgh Press, Jason Lee Baker

UNLV Theses, Dissertations, Professional Papers, and Capstones

Understanding the high-pressure behavior of transport properties has been a driving force in the study of materials under extreme conditions for well over a century being pioneered by P.W. Bridgman in the early 20th century. Research dedicated to the study of these properties leads to a variety of important applications: exploration of insulator to semi-conductor to metal, structural, and electronic phase transitions, correlation of pressure-induced structural phase transitions and the electronic properties along phase boundaries, identifying electronic topological transitions, testing the validity of theoretical models and providing input parameters for calculations at high-pressure and high-temperature conditions, exploration of sample synthesis …

Numerical Methods For Option Pricing Under The Two-Factor Models, Jiacheng Cai

UNLV Theses, Dissertations, Professional Papers, and Capstones

Pricing options under multi-factor models are challenging and important problems for financial applications. In particular, the closed form solutions are not available for the American options and some European options, and the correlations between factors increase the complexity and difficulty for the formulations and implements of the numerical methods.

In this dissertation, we first introduce a general transformation to decouple correlated stochastic processes governed by a system of stochastic differential equations. Then we apply the transformation to the popular two-factor models: the two-asset model, the stochastic volatility model, and the stochastic interest rate models. Based on our new formulations, we …

Secular Resonances During Main-Sequence And Post-Main-Sequence Planetary System Dynamics, Jeremy L. Smallwood

UNLV Theses, Dissertations, Professional Papers, and Capstones

We investigate gravitational perturbations of an asteroid belt by secular resonances. We ap- ply analytic and numerical models to main–sequence and post–main–sequence planetary systems. First, we investigate how the asteroid impact rate on the Earth is affected by the architecture of the planetary system. We find that the nu6 resonance plays an important role in the asteroid collision rate with the Earth. Compared to exoplanetary systems, the solar system is somewhat special in its lack of a super–Earth mass planet in the inner solar system. We therefore consider the effects of the presence of a super–Earth in the terrestrial planet …

The Formation And Dynamics Of Clouds In The Environment Of Active Galactic Nuclei, Timothy Waters

UNLV Theses, Dissertations, Professional Papers, and Capstones

Active galactic nuclei (AGN) are among the most luminous objects in the universe and are known to be powered by accretion onto supermassive black holes in the centers of galaxies. AGN clouds are prominent components of successful models that attempt to unify the diversity of AGN. These clouds are often hypothesized to be the source of the broad and narrow line emission features seen in AGN spectra. Moreover, the high column densities of gas needed to account for broad absorption lines has been attributed to the same population of clouds, while the motion of AGN clouds has been invoked to …

Improved Partial Charge Models In Siliceous Zeolites For The Simulation Of Adsorption And Identification Of Catalytic Sites, Jarod J. Wolffis

UNLV Theses, Dissertations, Professional Papers, and Capstones

Utilization of computational modelling and simulation is expanding as computer processing power has increased and as new tools have been developed. This thesis focuses on efforts to improve the accuracy of simulations in aluminosilicate zeolites, an industrially important category of materials for catalysis and separations. For these sorbents, partial atomic charge represents a critical parameter in molecular mechanics simulations, determining the Coulombic non-bonding interaction. Partial charges may also be used as a measure of important physical parameters of the system such as the degree of covalency or the relative acidity of catalytic sites. We compare several common methods for predicting …

Understanding Progenitors Of Gamma Ray Bursts With Multi-Wavelength Properties, Ye Li

UNLV Theses, Dissertations, Professional Papers, and Capstones

Gamma-ray bursts (GRBs) are among the most brilliant explosions in the universe, named for their intense, seconds-duration $\gamma$-ray emission. They are generally classified into two categories according to the durations of their $\gamma$-ray emission: the long-duration GRBs (LGRBs) with durations more than 2 seconds, and the short-duration GRBs (SGRBs) with durations less than 2 seconds. Most SGRBs are believed to originate from mergers of compact stars (e.g., neutron star-neutron star and neutron star-black hole; also known as Type I GRBs by their physical mechanism), while the LGRBs are thought to originate from core-collapse of massive stars (Type II). In addition …

Remote Sensing Of The Environmental Impacts Of Utility-Scale Solar Energy Plants, Mohammad Masih Edalat

UNLV Theses, Dissertations, Professional Papers, and Capstones

Solar energy has many environmental benefits compared with fossil fuels but solar farming can have environmental impacts especially during construction and development. Thus, in order to enhance environmental sustainability, it is imperative to understand the environmental impacts of utility-scale solar energy (USSE) plants. During recent decades, remote sensing techniques and geographic information systems have become standard techniques in environmental applications. In this study, the environmental impacts of USSE plants are investigated by analyzing changes to land surface characteristics using remote sensing. The surface characteristics studied include land cover, land surface temperature, and hydrological response whereas changes are mapped by comparing …