Digital Commons Network^™

Pressure And Heat Flux Effects On The Heat Transfer Characteristics Of Liquid Methane, Chance Paul Garcia

Open Access Theses & Dissertations

The heat transfer effects on liquid methane are investigated with the use of a carbo-thermal rig at the Center for Space Exploration Technology Research (cSETR) located at the University of Texas at El Paso (UTEP). The cSETR carbo-thermal rig design approach is presented along with the design of a methane condensing mobile unit (MCMU) to supply the laboratory and rig with liquid methane. The proposed research will generate useful insight in to heat transfer coefficient behavior, non-dimensional correlations, different flow conditions, varied inlet conditions, and varied heat flux for a subscale test article applicable to a regenerative cooled rocket engine …

A Case Study Towards Verification Of The Utility Of Analytical Models In Selecting Checkpoint Intervals, Michael Joseph Harney

Open Access Theses & Dissertations

As high performance computing (HPC) systems grow larger, with increasing numbers of components, failures become more common. Codes that utilize large numbers of nodes and run for long periods of time must take such failures into account and adopt fault tolerance mechanisms to avoid loss of computation and, thus, system utilization. One of those mechanisms is checkpoint/restart. Although analytical models exist to guide users in the selection of an appropriate checkpoint interval, these models are based on assumptions that may not always be true. This thesis examines some of these assumptions, in particular, the consistency of parameters like Mean Time …

Application Of Various Remote Sensing And Aerial Photography Data Sets To Resolve Surface Structure In Areas Of Poor Exposure: Examples From Kamchatka Peninsula, Russia And Katalla Area, Alaska Usa, Sarah Natalie Heinlein

Open Access Theses & Dissertations

For many years now remote sensing data sets and application techniques of these various data have been routinely used in geological studies. Some of these studies are as basic as using Google Earth applications for general reconnaissance to more sophisticated methods for energy exploration or development of active tectonic models for a region. This dissertation presents data from two study areas within the northern pacific region utilizing a number of remote sensing and aerial photography data: 1) Kamchatka Peninsula, Russia, and 2) Katalla area of southern Alaska, USA. The Kamchatka Peninsula, Russia study evaluates surface geomorphology which includes the morphology …

Solving Logistic System Design Problem Considering Various Biomass Feedstock Using Two Metaheuristic Optimization Methods, Jesusita Ibarra

Open Access Theses & Dissertations

Bioenergy has become an important source of energy; it can be used as an alternative to fossil fuel energy, and it offers significant potential to alleviate climate change by reducing greenhouse gas emissions caused by the burning of fossil fuels. The Energy Independence and Security Act decrees the use of 21 billion gallons of advanced biofuel including 16 billion gallons of cellulosic biofuels by the year 2022. It is easy to observe that biomass can make a considerable contribution meet the energy demands. On the other hand, the supply of sustainable energy is one of the main challenges that must …

Security Games With Interval Uncertainty, Md Towhidul Islam

Open Access Theses & Dissertations

Game theory has become an important tool in solving real-life decision making problems. Security games use the concept of game theory in adversarial scenarios to protect critical infrastructure. The main purpose of security games is to allocate security resources among various targets and maximize payoff for the defender considering various kinds of attackers. It is hard for domain experts to predict the attacker's behavior, so one of the major challenges in describing this game model is representing uncertainty about the attacker's payoff. Several approaches have been developed to generate these game models based on uncertainty, such as Bayesian games. However …

Automatic Memory Management Policies For Low Power, Memory Limited, And Delay Intolerant Devices, Md Abu Jahid

Open Access Theses & Dissertations

Mobile devices such as smartphones and tablets are energy and memory limited, and implement graphical user interfaces that are intolerant of computational delays. Mobile device platforms supporting apps implemented in languages that require automatic memory man- agement, such as the Dalvik (Java) virtual machine within Google's Android, have become dominant. It is essential that automatic memory management avoid causing unacceptable interface delays while responsibly managing energy and memory resource usage. Dalvik's automatic memory management policies for heap growth and garbage collection scheduling utilize heuristics tuned to minimize memory footprint. These policies result in only marginally acceptable response times and garbage …

New Topics On Nanoindentation Of Polymers And Composite Materials, Ricardo Martinez-Hernandez

Open Access Theses & Dissertations

In this study, nanoindentation was used to determine Young's modulus of homogeneous plastic materials as well as inhomogeneous epoxy woven fabric composites using various indenters. In the first part, homogeneous PMMA and polycarbonate were characterized using conical and spherical indenters. The conventional approach of the inverse analysis was modified in order to account for effects obtained during spherical nanoindentation. The experimental results were verified using FEA analysis in ABAQUS. It was found that viscous effects were present in conical nanoindentations which led to an overestimation of contact stiffness. The second part, the response of carbon and glass fiber woven fabric …

Optimization Of Biomass Logistics System Using Genetic Algorithm And Particle Swarm Optimization For Biofuel Production, Ethel Regina Martinez-Schabez

Open Access Theses & Dissertations

As time goes by, Renewable Energy keeps proving to be an important and potential replacement for fossil fuels. All the different types of Renewable Energy offer a relief to the environmental aftermaths of the prolonged reliance on fossil fuel energy. Bioenergy is one of the types of Renewable Energy that can help by minimizing the emissions of fossil fuels. The Energy Independence and Security Act mandates the use of 21 billion gallons of advanced biofuels including 16 billion gallons of cellulosic biofuels by the year 2022. Biomass and Biofuels can clearly become a significant aid to sustainably supply energy in …

Modeling Visibility In The El Paso Del Norte (Pdn) Region, Richard Medina Calderon

Open Access Theses & Dissertations

Poor visibility is a subject of growing public concern throughout the U.S, and an active area of research. Its societal impacts on air quality, aviation transport and traffic are significant. Aerosols play a fundamental role in the attenuation of solar radiation, and also affect visibility. The scattering and extinction coefficients of aerosol particles in the Paso del Norte Region have been calculated using the T- matrix model in conjunction with a laser particle counter. Inter-comparison of the model's results of the scattering and absorption coefficients against the corresponding data from a Photoacustic extinctiometer instrument (which measures in-situ absorption and scattering …

Method Development For A Chemical And Biological Analysis Of Glucocorticoids In Wastewater, Maria Carmen Lozano

Open Access Theses & Dissertations

Glucocorticoids are a class of steroid hormones that can either be produced synthetically or naturally by the adrenal glands. The synthetic glucocorticoids are highly prescribed in the United States for their anti-inflammatory and immunosuppressive properties to treat a variety of ailments and diseases; however, these have been implicated in a number of adverse human conditions such as obesity, metabolic syndrome, immune-suppression, delayed puberty, adrenal insufficiency and Cushing Syndrome, among others. Ongoing research has shown that synthetic and natural hormones are transported to aquatic environments via mammalian excretion or wastewater effluent, and as a result, the release of glucocorticoids into the …

Endocrine Disrupting Compound 4-Nonylphenol And Neurodegeneration, Jessica Martinez Jurado

Open Access Theses & Dissertations

Neurodegeneration, a progressive loss of nerve cells (neurons), occurs in many neurological disorders including Alzheimer's disease, Parkinson's disease, Schizophrenia, and drug addiction. Cytoskeletal disruption in neurons and aggregation of proteins associated with these disorders is the hallmark of neurodegeneration. However, the cause of neurodegenerative disorders is unknown and currently there are no effective drug treatments. Aging is the most consistent risk factor for developing a neurodegenerative disorder, and recent evidence suggests that environmental factors, which act as endocrine disruptors, pose a risk in the disease process. 4- nonylphenol (4-NP), an endocrine-disrupting compound (EDC), has been shown to affect brain development …

Assessment Of Water Quality And Benthic Macroinvertebrate Community In A Wastewater Receiving Constructed Wetland, Jennifer Lynn Martinez

Open Access Theses & Dissertations

In the El Paso region around the 1930s there was a loss of riparian areas and wetlands due to canalization of the Rio Grande. In an attempt to bring back native flora and fauna that once flourished in the floodplain of the Rio Grande region, the creation of Rio Bosque Wetlands Park (RBWP; El Paso Co., TX) was initiated in 1995. As part of the construction agreement, El Paso Water Utilities agreed to provide water to fill the wetland upon its completion. Beginning in 1998, RBWP was filled with treated effluent from the adjacent Roberto Bustamante Wastewater Treatment Plant (WWTP) …

Organic Photovoltaics: A Charge Transfer Perspective In The Study Of Donor-Acceptor Systems, Marco Olguin

Open Access Theses & Dissertations

The present research involves the study of donor-acceptor (D/A) dyad complexes from a charge transfer energy perspective. The aim is to provide insight and predictive understanding into the charge transfer processes of the molecular-level components in donor-acceptor based organic solar cells using computational methods to describe photochemical processes at the quantum mechanical level within the Density Functional Theory (DFT) approximation. Predictive understanding is anchored in reproducing experimental results, wherein the present work a perturbative excited-state DFT method is described in detail and shown to give Charge Transfer (CT) energies in excellent agreement with benchmark experimental data. With an accurate excited …

Crystal Structure, Phase, And Optical Properties Of Yttrium-Doped Hafnium Oxide Nanocrystalline Thin Films, Alejandro Ortega

Open Access Theses & Dissertations

Yttrium-doped hafnium oxide (YDH) nanocrystalline films were produced by sputter-deposition at various substrate times and temperatures, to produce YDH films in a wide range of thicknesses, dYDH∼25 to 1100 nm. The deposition was made onto optical grade quartz and sapphire substrates. Samples deposited on sapphire were subject to post-deposition annealing (PDA) at various times (3-24 hr) and temperatures (1100 - 1500 °C). The effect of d[special characters omitted]YDH on the crystal structure, surface/interface morphology and optical properties of YDH films was investigated. X-ray diffraction analyses revealed the formation of monoclinic phase for relatively thin films (<150nm). The evolution towards stabilized cubic phase with increasing dYDH [special characters omitted]is observed. The scanning electron microscopy results indicate the dense, columnar structure of YDH films as a function of dYDH. Spectrophotometry analyses indicate that the grown YDH films are transparent and exhibit interference fringes. The band gap was found to be ∼ 5.60 eV for monoclinic YDH films while distinct separation and an increase in band gap to 6.03 eV is evident with increasing dYDH and formation cubic YDH films. The PDA films band gaps were found to be between 5.31 and 5.72 eV, all of which exhibit secondary gaps. A correlation between growth conditions, annealing, phase evolution, and optical properties of the YDH nanocrystalline thin films is established.

Surface Plasmon Polaritons And Waveguide Modes At Structured And Inhomogeneous Surfaces, Javier Polanco

Open Access Theses & Dissertations

In chapter 1, properties of a p-polarized surface plasmon polariton are studied, propagating circumferentially around a portion of a cylindrical interface between vacuum and a metal, a situation investigated earlier by M. V. Berry (J. Phys. A: Math. Gen. 8, (1975) 1952). When the metal is convex toward the vacuum this mode is radiative and consequently is attenuated as it propagates on the cylindrical surface. An approximate analytic solution of the dispersion relation for this wave is obtained by an approach different from the one used by Berry, and plots of the real and imaginary parts of its wave number …

Efficient, Scalable, Parallel, Matrix-Matrix Multiplication, Enrique Portillo

Open Access Theses & Dissertations

For the past decade, power/energy consumption has become a limiting factor for large-scale and embedded High Performance Computing (HPC) systems. This is especially true for systems that include accelerators, e.g., high-end computing devices, such as Graphics Processing Units (GPUs), with terascale computing capabilities and high power draws that greatly surpass that of multi-core CPUs. Accordingly, improving the node-level power/energy efficiency of an application can have a direct and positive impact on both classes of HPC systems.

The research reported in this thesis explores the use of software techniques to enhance the execution-time and power-consumption performance of applications executed on a …

An Econometric Approach For Modeling Population Change In Arkansas, David Alexandro Ramirez

Open Access Theses & Dissertations

This study models population in the state of Arkansas using a small econometric model, and is similar to a previous demographic model developed by Fullerton and Barraza de Anda (2008). The components of population change consist of births, deaths, and net migration. Births minus deaths equal natural increase, and population in the current period is population from the previous period plus natural increase plus net migration. Births and deaths are modeled as functions of a one period autoregressive lag as well as national trends. Net migration is also modeled as a one period lag of itself in addition to relative …

Preparing Teachers For Use Of Impact Activities: An Exploratory Study, Jeremy Lee Ramirez

Open Access Theses & Dissertations

The iMPaCT project team has developed three modules of activities that use programming on TI-83/84 calculators as a means to engage students to explore foundational concepts in Algebra I. The developers conducted a 3-day summer Professional Development Program (PDP) for teachers to become familiar with the objectives, pedagogy, assessments, and resources of the three modules of iMPaCT activities. I have collected and analyzed various forms of data such as videotapes of workshop sessions, teachers' written work and a pre-post assessment. The purpose of this study is to provide the program coordinators with information about the PDP for planning of future …

Propagation Of Interval And Probabilistic Uncertainty In Cyberinfrastructure-Related Data Processing And Data Fusion, Christian Servin

Open Access Theses & Dissertations

Data uncertainty affects the results of data processing. So, it is necessary to find out how the data uncertainty propagates into the uncertainty of the results of data processing. This problem is especially important when cyberinfrastructure enables us to process large amounts of heterogeneous data. In the ideal world, we should have an accurate description of data uncertainty, and well-justified efficient algorithms to propagate this uncertainty. In practice, we are often not yet in this ideal situation: the description of uncertainty is often only approximate, and the algorithms for uncertainty propagation are often not well-justified and not very computationally efficient. …

Depositional Setting And Sequence Stratigraphic Analysis Of The Lower Permian Lower Hueco Formation On The Western Margin Of The Orogrande Basin, South Central New Mexico, Jonathon Eric Stautberg

Open Access Theses & Dissertations

On the western margin of the Orogrande Basin in south-central New Mexico, eight outcrop datasets, in the form of measured stratigraphic sections from the lower interval of the Lower Permian Lower Hueco Formation were analyzed in regard to depositional facies distribution and sequence stratigraphy. Based on petrographic analysis of 247 samples and associated field relationships, 11 depositional facies are recognized: 1) quartz sandstone, 2) quartz siltstone and shale, 3) fenestral dolomudstone, 4) microbial intraclast packstone, 5) dolomudstone, 6) green-algal packstone to grainstone, 7) ostracode foram wackestone, 8) oolitic packstone, 9) fossiliferous packstone and grainstone, 10) fusulinid packstone and grainstone, 11) …

Expanding The Pipeline For Latino Bilingual Teachers: A Mixed Methods Study, Amabilia Valverde Valenzuela

Open Access Theses & Dissertations

Current education reform in the US requires teacher preparation programs to educate future teachers according to the certification standards set forth by each state. Certification for teaching in Texas requires that preservice teachers successfully complete a series of comprehensive examinations in their teaching fields and in professional knowledge before entering full-time teaching. However, researchers have argued (Gitomer, Brown, & Bonett, 2011) that the use of standardized tests often raises concerns about adverse impacts on members of minority groups, who often have lower test scores. The purpose of this research was twofold: First, to analyze factors that predict Mexican American teacher …

Impact Of Cerium Oxide Nanoparticles On Cilantro (Coriandrum Sativum), Maria Isabel Morales

Open Access Theses & Dissertations

Studies have shown that plants exposed to ENPs suffer different types of stress. Other studies have revealed that plants can take up and accumulate CeO2 NPs without modification. Thus, these NPs could enter the food chain through edible plants, posing a threat for human health. Cilantro (Coriandrum sativum) is a worldwide culinary and medicinal plant consumed either as a fresh herb or a spice. In this research, cilantro plants were germinated and cultivated for 30 days in organic soil treated with CeO2 NPs at concentrations varying from 0 to 500 mg kg!1. Subsequently, plant organs were analyzed by using spectroscopic …

Model Fusion: A New Approach To Processing Heterogeneous Data, Omar Ochoa

Open Access Theses & Dissertations

In many practical situations, it is necessary to extract

information from data of different types. For example, in geosciences, several sources of data can be used to determine the interior structure of the earth: the first arriving waves from earthquakes and from man-made sources, measurements of the earth's gravity field, measurements of the dispersion of surface waves generated by earthquakes, etc. At present, most existing data processing techniques deal only with data of one type.

A joint use of all the information derived from multiple types of data sources is an important theoretical and practical challenge. Such a joint use …

Carbon Emissions From Soil Respiration In The Northern Chihuahuan Desert Shrubland, Anna Cristina Ortiz

Open Access Theses & Dissertations

The United States Department of Agriculture's Jornada Experimental Range (JER), is located in the northern Chihuahuan Desert in southern New Mexico and historically functioned as an experimental rangeland for cattle grazing. Historical grazing in the US Southwest has been identified as a leading, but not the sole, factor that has led to the conversion of pristine grasslands to shrublands, such has been the case on the JER. The estimated increased variability in precipitation intensity and frequency that is predicted to occur with climate warming will likely affect ecosystem responses from ecological processes including primary productivity, microbial decomposition, and thus respiration. …

Photochemical Synthesis Of Amino Acid And Peptide Oxo-Esters, Alfredo Ornelas

Open Access Theses & Dissertations

Amino acid and peptide oxo-esters have played an important role in peptide chemistry for many years. Various amino acid esters are commonly used as protecting groups for peptide synthesis in solution. Moreover, activated phenyl ester derivatives have been used for chemical ligation of peptides. However, the synthesis of amino acid and peptide oxo-esters is commonly performed under acidic or basic conditions. Under acidic conditions, acid-sensitive protecting groups may be cleaved, and under basic conditions racemization of amino acid esters is a common problem. Here we present the photochemical synthesis of amino acid and peptide oxo-esters. Based on the photochemical properties …

Novel Copper (Ii) Mediated Transfection Nano-Systems And Biological Properties Of Pyridinium Surfactants, Sarit Pal

Open Access Theses & Dissertations

Efficacy of gene therapy is relied upon the improvement of gene delivery vectors into mammalian cells. Although viral-based polynucleotide carriers are still considered as the most common method for gene delivery but the cost effectiveness, nonspecific lethal immune response has evoked the renaissance of non-viral synthetic delivery systems. An initial discovery by Felgnar et al showed Cationic Liposomes (CLs) (having an overall positive charge) when mixed with DNA to form CL-DNA complexes can enhance the transfer of polynucleotides into cells followed by its expression. Presently, a flurry of experimental works is taking place for the better understanding of structural characterization …

Geochemical Characterization Of Mineral Dust Sources In The Chihuahuan Desert And Southern High Plains Regions, Porfirio Peinado

Open Access Theses & Dissertations

The Chihuahuan Desert (northern Chihuahua, southern New Mexico, and far west Texas) and the southern High Plains (west Texas and eastern New Mexico) regions have been identified as one of the most persistent dust producing regions of North America. Regional-scale dust storms have been observed by satellite imagery to identify sources of dust, resulting in collection and examination of physical soil samples to better understand the source signatures (geochemical characteristics) of dust origins in these two regions.

The soil characteristics were examined through several techniques: Particle Size Distribution, X-Ray Diffraction (XRD), Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), and Total …

Environmental Education Through The Lens Of Diverse Elementary School Students In The United States: A Phenomenographic Study, Brissa Yazmin Quiroz

Open Access Theses & Dissertations

Global environmental change is occurring, putting our planet under pressure. Children need to understand not only why the environment is important, but also their role as citizens of a globalized society and their necessary contribution to solving global problems. Students carry their own perspectives about the environment and education, and these differing perspectives should be a significant topic for environmental education research. Recent research studies have included the conceptualization of nature and the environment through children's eyes; yet, no studies have examined the concept of environmental education through the eyes of diverse children. Minority voices and experiences are not frequently …

A Quantitative Approach Using An Axiomatic Design Framework To A Medication Distribution System, Pepito Raguini

Open Access Theses & Dissertations

As the need to minimize medication errors drives many medical facilities to come up with robust solutions to the most common error that affects patient's safety, these hospitals would be wise to put a concerted effort into finding methodologies that can facilitate an optimized medical distribution system. If the hospitals' upper management is looking for an optimization method that is an ideal fit, it is just as important that the right tool be selected for the application at hand. In the present work, we propose the application of Axiomatic Design (AD), which is a process that focuses on the generation …

Unconstrained L1 Optimization With Applications To Signal And Image Processing, Carlos Andres Ramirez

Open Access Theses & Dissertations

In recent years, the applied mathematical community has witnessed a revolution that is changing the paradigm of classical signal and image processing. Novel and e efficient numerical algorithms have emerged for solving new challenges in large scale signal retrieval, where both constrained and unconstrained L1 minimization methods play a fundamental role.

In this work, we present a new methodology for solving unconstrained L1 minimization problems in the context of image and signal processing. Our approach consists in solving a sequence of relaxed unconstrained minimization problems depending on a positive regularization parameter that converges to zero. The optimality conditions of each …