Digital Commons Network^™

Raman Microscopic Analysis Of Internal Stress In Boron-Doped Diamond Thin Films, Emma M.A. Sundin

Open Access Theses & Dissertations

The correlations between induced stress on undoped and boron-doped diamond (BDD) thin films, sample chemical composition, and fabrication substrate are investigated in this study via confocal Raman microspectroscopic analysis. Stability of BDD films is relevant to fast-scan cyclic voltammetry, as film delamination and dislocation of BDD-coated electrodes that can occur during neurosurgical electrode implantation can negatively impact the biosensing reliability of this technique. Electrodes were fabricated by coating cylindrical tungsten rods using a custom-built chemical vapor deposition reactor. The results of the analysis reveal a direct correlation between regions of pure diamond and enhanced material stress, as well as preferential …

Evaluation Of A Roller Method For Geochemical Leach Testing, Troy Allen Svede

Open Access Theses & Dissertations

Currently, multiple tests are being used when evaluating an MSE wall backfill material for pH, conductivity, chloride concentration, and sulfate concentration. There is no one test to measure all four characteristics when testing a soil. Texas Department of Transportation (TxDOT) uses four different tests to measure these characteristics. The goal of this research was to refine a simplified test procedure that was created by David Borrok et al., the Tex-620-M. The method that was developed to replace the current TxDOT test procedures Tex-620-J, Tex-128-E, and Tex-145-E test procedures is the Tex-620-M2. Leaching kinetics were analyzed for gravel and fines by …

Design And Regioselective Synthesis Of Fullerene Derivatives For Metal-Organic Hybrid Architectures, Catalina Suarez

Open Access Theses & Dissertations

In the last years different fullerene derivatives and endohedral fullerenes have been reported and their potential applications as electronic, magnetic, catalytic, biological and optical materials have been explored. In this work we describe the characterization of new endohedral fullerenes; the exohedral functionalization of fullerenes with organic addends or metal clusters and their application in metal-organic hybrid architectures.

We synthesized fullerene polymers with a variety of staircase linear architectures, zigzag polymers and a perfectly linear polymer using an hexakis-fullerene adduct with two 4,5-diazafluorene groups located at trans-1 positions, using Hg, Cd, Zn and33 Cu as the metal centers. Our results showed …

Active Learning Effect On The Public's Perception Of Anthropogenic Global Climate Change, Ivy Gisselle Trevizo

Open Access Theses & Dissertations

Anthropogenic, or human-caused global climate change has been debated for many years among the public despite the growing evidence that there is scientific consensus on this topic. A gap has been discovered between scientific evidence of increasing temperatures and the public's perception on climate change. This gap has been hypothesized to come from the method in which the scientific community represents scientific evidence. The goal of this study was to determine if active learning techniques around local and regional climate change and climate change impacts changes the awareness, perception, and behavioral intentions of different segments of the public. The study …

Neutrino Oscillations And The Reno Experiment, Karla Rosita Tellez Giron Flores

Open Access Theses & Dissertations

Neutrinos are the second most common particles in the universe, after the photons. Neutrinos (and antineutrinos) exist in three different "flavors", namely, electron, tau and muon neutrinos. A physical neutrino, however, can oscillate among these three flavors and, thus, it is said to be a mix of the three flavor states. In quantum mechanics representation, it is said that the three flavor states are the mixture of the three mass states. This mixture of neutrinos can generally be parameterized by the three so-called mixing angles (&thetas;12, &thetas;23, &thetas;13), three squared mass differences Δmij 2, i, j = 1, 2, 3 …

Synthesis And Post-Synthetic Transmetalations Of Metal-Organic Frameworks Containing Bimetallic Centers, Jose Miguel Veleta

Open Access Theses & Dissertations

The heterobimetallic metal-organic frameworks (MOFs) of the type HKUST-1 were obtained through post synthetic cation exchange processes, where Cu3(BTC)2 (BTC = 1,3,5-benzenetricarboxylate) was exposed to solutions of Mn2+, Fe2+, Co2+, or Ni2+ at time intervals of 6, 12, 24, 36, 48, and 72 hours. The elemental composition of the products was analyzed by inductively coupled plasma optical emission spectroscopy (ICP-OES), showing partial substitution of copper ions in the frameworks. Transmetalations done with Mn2+ and Ni2+ show a relatively low cation exchanged through the different time intervals, with maximum transmetalation percentages of 2.4 % for Mn2+ and 2 % for Ni2+ …

Design Optimization For Heat Dissipation In Polymer Additive Manufacturing With Joule Heating, Tania Alejandra Ventura

Open Access Theses & Dissertations

Nowadays, the use of additive manufacturing (AM) is mainly focused on the production of prototypes with the purpose of evaluating a design. This industry has become a subject of constant reinvention; in fact, an emerging application of AM is focused on creating parts with embedded electronics. However, the development of both traditional and additive manufactured electronics has led to an increase in power densities and size reduction. Consequently, thermal management has become essential in electronics, as overheating decreases reliability of the component leading to a premature failure.

In this study, a polycarbonate component design with integral electrical circuitry that is …

Spectroscopic Analysis Of Neurotransmitters: A Theoretical And Experimental Raman Study, Matthew Alonzo

Open Access Theses & Dissertations

Surface-enhanced Raman spectroscopy (SERS) was applied to investigate the feasibility in the detection and monitoring of the dopamine (DA) neurotransmitter adsorbed onto silver nanoparticles (Ag NPs) at 10-11 molar, a concentration far below physiological levels. In addition, density functional theory (DFT) calculations were obtained with the Gaussian-09 analytical suite software to generate the theoretical molecular configuration of DA in its neutral, cationic, anionic, and dopaminequinone states for the conversion of computer-simulated Raman spectra. Comparison of theoretical and experimental results show good agreement and imply the presence of dopamine in all of its molecular forms in the experimental setting. The dominant …

Label-Free Raman Imaging To Monitor Breast Tumor Signatures, John Ciubuc

Open Access Theses & Dissertations

Methods built on Raman spectroscopy have shown major potential in describing and discriminating between malignant and benign specimens. Accurate, real-time medical diagnosis benefits in substantial improvements through this vibrational optical method. Not only is acquisition of data possible in milliseconds and analysis in minutes, Raman allows concurrent detection and monitoring of all biological components. Besides validating a significant Raman signature distinction between non-tumorigenic (MCF-10A) and tumorigenic (MCF-7) breast epithelial cells, this study reveals a label-free method to assess overexpression of epidermal growth factor receptors (EGFR) in tumor cells. EGFR overexpression sires Raman features associated with phosphorylated threonine and serine, and …

Essays On Sofwtare Development Projects: Impact Of Social And Technological Factors On Project Performance And Co-Diffusion Of Software Sourcing Arrangements, Niharika Dayyala

Open Access Theses & Dissertations

Software development is a complicated process which is accomplished by the combined effort of the key elements such as people, processes, and technology. Software development firms are on a constant quest to identify the best practices for managing the key elements to improve their software development project outcomes and to deliver successful software projects. This Dissertation aims to study key elements that can influence the software development project performance through three distinctive studies. The first essay of this Dissertation investigates the impact of people factors on software project outcomes. Specifically, it examines the impact of team characteristics on the software …

The Human Mitochondrial Chaperonin: It Takes Two Single-Rings To Tango, Adrian Sergio Enriquez

Open Access Theses & Dissertations

The human mitochondrial chaperonin is a macromolecular machine that catalyzes the proper folding and assembly of newly imported mitochondrial proteins into their biologically active state. It is composed of two proteins from the highly conserved heat shock protein family, hsp10 and hsp60, that assemble into large oligomeric complexes responsible for mediating the folding of non-native polypeptides in an ATP dependent manner. In addition to its innate role in protein folding, human mitochondrial hsp60 has been implicated in numerous moonlighting cellular activities that have been linked to diseases conditions such as cancer and neurodegeneracy. In light of its cellular importance, the …

High School Students' Views Of Science In A University Science Internship With Cogenerative Dialogues, Gabriel M. Hayes

Open Access Theses & Dissertations

The purpose of this Thesis is to determine how participation in long term university science internships affect nature of science (NOS) conceptual change in high school students. The study was conducted on high school students who volunteered to participate in a seven month university science internship in west Texas. Student views of NOS were measured by pre- and post-internship interviews using five questions about NOS. Internship and no internship student responses were qualitatively analyzed to show change in views of NOS. Findings indicated that participation in long term science internships with cogenerative dialogues improved students conceptualizations of the social dimensions …

Crash Rate As A Function Of Access Point Density And Traffic Flow, George Pinal

Open Access Theses & Dissertations

High crash rates on U.S. highways results in a considerable loss of human and economic resources. It is estimated that the U.S. loses about $10 billion every year in motor vehicle crashes in terms of fatalities, injuries, and property damage. Demand for access points from highways to properties has steadily increased due to rapid growth in local economies creating thereby compromises between accessibility and mobility or capacity and safety. On the other hand, the availability of access is essential to residential and commercial developments and often occurs at the cost of safety and traffic operations. This often directs the need …

Analysis Of Gesture Frequency And Amplitude As A Function Of Personality In Virtual Agents, Alex Michael Rayon

Open Access Theses & Dissertations

Embodied conversational agents are changing the way humans interact with technology. Agents are expected to behave like people, both verbally and non-verbally. Researchers within the Human-Computer Interaction community have found many attributes of an agentâ??s gesture contribute to an agentâ??s perceived personality and believability.

Gesture amplitude and frequency are two of the attributes that contribute to the naturalness of a gesture. Currently, no previous studies have defined an empirical baseline for generating natural gestures for these two attributes. I seek to discover whether gesture amplitude and frequency affect how users perceive an agentâ??s naturalness, and which gestures would be preferred …

Development Of An Alternative Laboratory Testing Procedure For Tensile Characterization Of Cement Stabilized Base Layers, Jose Antonio Tarin

Open Access Theses & Dissertations

Proper characterization of the fatigue performance of stabilized materials in the laboratory is an integral component of the structural design of stabilized layers in multi-layer pavements. The new mechanistic pavement design protocols require modulus of rupture of the stabilized base layers as an input to the fatigue performance models. This study discusses the practical and theoretical discrepancies associated with the traditional tensile strength tests, and provides an alternative testing procedure for the determination of the tensile strength of the stabilized materials in the laboratory. To achieve this objective, a full factorial laboratory experiment design consisted of four aggregate sources with …

Advancing High Spatial And Spectral Resolution Remote Sensing For Observing Plant Community Response To Environmental Variability And Change In The Alaskan Arctic, Sergio Armando Vargas

Open Access Theses & Dissertations

The Arctic is being impacted by climate change more than any other region on Earth. Impacts to terrestrial ecosystems have the potential to manifest through feedbacks with other components of the Earth System. Of particular concern is the potential for the massive store of soil organic carbon to be released from arctic permafrost to the atmosphere where it could exacerbate greenhouse warming and impact global climate and biogeochemical cycles. Even though substantial gains to our understanding of the changing Arctic have been made, especially over the past decade, linking research results from plot to regional scales remains a challenge due …

Bragg Gratings In Polarization Maintaining Optical Fiber As Three Dimensional Strain Sensor, Joel Quintana

Open Access Theses & Dissertations

Fiber-Bragg Gratings (FBG) for Structural Health Monitoring (SHM) have been studied extensively as they offer electrically passive operation, electromagnetic interference (EMI) immunity, high sensitivity and multiplexing as compared to conventional electric strain sensors. FBG sensors written within polarization maintaining (PM) optical fiber offer ad- ditional dimensions of strain measurement, greatly reducing the number of sensors needed to properly monitor a structure. This reduction however, adds complexity to the dis- crimination of the sensorâ??s optical response to its corresponding applied strains. This Dissertation defines the set of algorithms needed to measure planar strain using PM-FBGs exclusively. It defines the minimum number …

Imaging Live Drosophila Brain With Two-Photon Fluorescence Microscopy, Syeed Ehsan Ahmed

Open Access Theses & Dissertations

Two-photon fluorescence microscopy is an imaging technique which delivers distinct benefits for in vivo cellular and molecular imaging. Cyclic adenosine monophosphate (cAMP), a second messenger molecule, is responsible for triggering many physiological changes in neural system. However, the mechanism by which this molecule regulates responses in neuron cells is not yet clearly understood. When cAMP binds to a target protein, it changes the structure of that protein. Therefore, studying this molecular structure change with fluorescence resonance energy transfer (FRET) imaging can shed light on the cAMP functioning mechanism. FRET is a non-radiative dipole-dipole coupling which is sensitive to small distance …

Self-Interaction Corrected Polarizabilities Of Small Molecules, Sharmin Akter

Open Access Theses & Dissertations

Density Functional Theory (DFT) is one of the most successful and popular computational Quantum Mechanical approaches to understand materials. DFT allows the prediction of material properties from the electron density. Although in principle density functional theory is exact, it, however, relies on approximate functional for exchange-correlation energy. Due to the approximate nature of the exchange-correlation functional, the self-Coulomb energy of the electrons is not exactly canceled out by the self-exchange leading the spurious self-interaction error (SIE). This error is responsible for the unphysical orbital energies of DFT and delocalization of the orbitals. The orbital energies of the valence electrons are …

Depositional Controls And Sequence Stratigraphy Of Lacustrine To Marine Transgressive Deposits In A Rift Basin, Lower Cretaceous Bluff Mesa, Indio Mountains, West Texas, Andrew Anderson

Open Access Theses & Dissertations

Successful hydrocarbon exploration in former rift basins of the South Atlantic pre-salt has generated interest in understanding depositional, diagenetic, and stratigraphic controls on pre-salt deposits. However, most studies to date have focused on attributes and controls on presalt lacustrine carbonate reservoir systems and little work has been done on the overlying marine sealing facies. Currently our standard sequence stratigraphic model of marine transgression of rift systems involves a single pulse of marine flooding over fluvially-incised valleys resulting in backstepping of fluvial and estuarine siliciclastic facies within the erosionally confined zone of an incised valley. However, the pre-salt systems of the …

Studies Of Air Pollutants And Their Impact On Respiratory And Cardiovascular Diseases In The El Paso Del Norte Region With Emphasis On Mobile Emissions, Juan Gustavo Arias Ugarte

Open Access Theses & Dissertations

Air pollution may cause different diseases, such as cardiovascular and lung diseases. Traffic is a major source of mobile emissions causing air pollution. Exhaust emissions from mobile sources (Emissions of Carbon Monoxide, Nitrogen Oxides and Hydrocarbons) and Non-exhaust (Brake and Tire) are complex mixtures of gases and dust, including a large number of ultrafine particles, especially in areas with high traffic density. Recent studies have shown high rates of morbidity and mortality in people exposed to these types of emissions because the fine and ultrafine particles can be transported from the respiratory airways to the organs, thus contributing to increase …

Estimating The Coefficients Of A Linear Differential Operator, Maria Ivette Barraza

Open Access Theses & Dissertations

Principal Differential Analysis (PDA; Ramsay, 1996) is used to obtain low dimensional representations of functional data, where each observation is represented as a curve. PDA seeks to identify a Linear Differential Operator (LDO) L = ω0I + ω 1D + ... + ωmDm, where I denotes the identity function and D j the jth derivative, that satisfies as closely as possible that Lx = 0 for each functional observation x. A theorem from analysis establishes that the coefficients of the LDO are in the Sobolev space, and thus can be approximated by B-splines. Current PDA software used to estimate the …

Electronic Structure Studies On Transition Metal Containing Endohedral Fullerenes, Carbon Onions And Zinc Sulfide Cages, Shusil Bhusal

Open Access Theses & Dissertations

We present the most stable structures for VXSc3-XN@C2n (where X=1-3 and 2n=70, 76, 78 and 80) using a systematic procedure that involves all possible isomers of the host fullerene cages. Subsequently, a detailed investigation of structural and electronic properties of the lowest energy isomers is performed using density functional theory in combination with large polarized Gaussian basis sets. The search procedure developed involved structural optimizations of thousands of fullerenes and correctly identifies the experimentally observed VSc2N@C80 and V2ScN@C80 isomer as the most stable structures. The structural analysis shows that a few V-doped endohedral fullerenes do not follow the isolated pentagon …

Investigation On A Cooling Channel Design For A High Heat Flux Oxy-Fuel Direct Power Extraction Combustor, Luisa Alejandra Cabrera Maynez

Open Access Theses & Dissertations

The implementation of oxy-fuel technology in fossil-fuel power generation could result in a drastic increase of system efficiencies and a reduction of emissions. While typical system temperatures are dictated by material constraints, open-cycle magnetohydrodynamic (MHD) power generators have the potential to utilize the energy of undiluted flames. This work presents design and modeling strategies to develop steady-state supersonic MHD combustors operating at temperatures exceeding 3000 K. Throughout the study, computational fluid dynamics (CFD) models were extensively used as a design and optimization tool. A proof-of-concept 60 kWth model was designed, manufactured and tested in accordance to methods relevant to rocket …

Utilizing Historical Mosquito Surveillance Data To Investigate The Efficacy Of Municipal Fogging In Controlling Mosquito Population Density, Andrea Betina Carzoli

Open Access Theses & Dissertations

Background: Mosquito borne diseases are the cause of many different disease syndromes and deaths in animals, both wild and domesticated, and humans of all ages and ethnicities. Though El Paso, TX is located in an arid region, mosquito populations are still rapidly growing in urban and agricultural communities and so are the mosquito borne illnesses. The most common vectors associated with mosquito borne illnesses in El Paso County are Culex quinquefasciatus, Culex tarsalis, and Aedes aegypti. Vector management is often the primary option to prevent and control outbreaks of mosquito borne illnesses and very often utilize fogging as the primary …

Synthesis Of New Fullerene Derivatives For Photovoltaic And Biological Applications, Edison Castro

Open Access Theses & Dissertations

Functionalized fullerenes exhibit improved solubility and different chemical and physical properties that allow applications in multiple fields such as photovoltaic and biological applications. Currently, perovskite solar cells (PSCs) are the most rapidly developing type of solar cells with certified efficiencies rising from 3.8% in 2009 to 22.1% in 2016. The good electron transporting and solution processable properties of most fullerene derivatives make them the most popular electron transporting materials (ETMs) in inverted perovskite solar cells (PSCs).

The work is reported in 11 chapters. We start with a fullerene overview followed by cleaver and elegant methodologies that allow the synThesis of …

Development Of Post-Pareto Optimality Methods For Multiple Objective Optimization, Juan Valentin Fernandez

Open Access Theses & Dissertations

In the past years, multiple objective optimization has been considered, as an important research area since in many real life problems there exists multiple criteria that need to be optimized simultaneously. The use of evolutionary algorithms or metaheuristic methods as solution methodologies lead to a large number of Pareto solutions rather than a single unique optimum. This Pareto-optimal set most of the time tends to be very large and the decision maker now faces the challenge of reducing its size to analyze a feasible number of solutions, thus deciding the best possible solution. In this work, two methods will be …

A Novel Approach To Enhancing Upper Extremity Coordination In Children With Autism Spectrum Disorder, Alejandra Sarahi Gamez Corral

Open Access Theses & Dissertations

With current estimates of 1 in 68 children being affected, Autism Spectrum Disorder (ASD) is regarded as one of the most rampant forms of disability globally. Although typically diagnosed through social impairment and repetitive stereotypical behavior, recent work has shown distinct motor impairments across the autism spectrum. These motor deficits can be gross or fine in nature and can be seen not only in reaching and grasping, but also in the kinematic composition of the actual movement, such as decreased velocity, decreased accuracy, irregular movement smoothness, etc. The goal of this study was to further the understanding of the kinematic …

Tracing Anthropogenic Salinity Inputs To The Semi-Arid Rio Grande River: A Multi-Isotope Tracer Approach, Sandra Garcia

Open Access Theses & Dissertations

Water is an important component for life and as such water quality and availability are major concerns in the world today. In arid to semi-arid regions, freshwater quality is especially important due to its scarcity. Elevated salinity of rivers in arid regions poses potentially devastating consequences for the communities that depend on these rivers as a source of freshwater. In the Rio Grande region, high salinity has led to severe reductions in crop productivity and accumulation of salts in soils. Salinity inputs into the river may come from both anthropogenic and natural sources. Thus, identifying and quantifying salinity inputs to …

Investigation Of Earthquake And Geyser Activity From Short-Term Nodal Array Deployment Centered At Old Faithful Geyser, Susana I. Garcia

Open Access Theses & Dissertations

Yellowstone National Park is home to an active caldera, centrally located on the North American continent. Several studies have concluded the existence of a hotspot that fuels the hydrothermal, geothermal and earthquake activity in the Yellowstone region. The geologic record of Yellowstone contains multiple layers of volcanic deposits that indicate the region experienced three previous massive volcanic eruptions dating back 2.05Mya, 1.2Mya and the most recent 640,000 years ago. Yellowstone is also home to one of the largest geothermal areas in the world. With this study, an in-depth look at seismicity and geyser events recorded within an active geothermal region, …