Physical Sciences and Mathematics Commons^™

Urban Water Demand In Arid-Regions: Modeling And Forecasting Climatic And Economic Effects, Tallen Ashley Capt

Open Access Theses & Dissertations

Water demand is an ever-growing concern for many municipalities around the world and understanding the driving forces of demand is critical to ensure sustainability. The goal of this research was to develop mechanistic models of urban water demand that could be used as decision support tools for regional water managers. This Dissertation research focused on modeling water consumption in El Paso, Texas at the daily and annual time scale for use in a long-term forecast. The Dissertation is divided into three major chapters: the first two chapters describe independent models on (1) meteorological and (2) economic effects, respectively. The third …

Mesacs: A Multi-Method Environmental Study Over The Arctic Chukchi Sea, Julio Eduardo Ceniceros

Open Access Theses & Dissertations

The Arctic environment is a dynamic part of Earth’s natural system and is currently undergoing rapid increasing air temperature and decreasing sea ice extent, leading to more open ocean waters. As open water areas become more prevalent, phytoplankton communities near the surface of the ocean can proliferate earlier in the year and are apt to reach higher concentrations by the end of the summer season. Phytoplankton biomass around the world has been known to produce a microscopic biofilm at the surface of the ocean composed of biogenic and biological particles which then become airborne and work as both cloud condensation …

Computational Studies On Perovskite-Metallofullerene Interface And Magnetic Properties Of Mn-Based Mixed Olivines, Bethuel Omutiti Khamala

Open Access Theses & Dissertations

Methyl ammonium lead halide (MAPbX3) perovskite based solar cells have recently emerged as promising class of materials for photovoltaic applications with efficiencies reaching over 22%. Designing interfaces with strong binding is vital to developing efficient, high-performing solar cells. Fullerene-based materials are widely employed as efficient electron acceptors and can serve as electron transporting layer in perovskite based solar cells. We have studied interfaces of methyl ammonium lead iodide MAPbI3 with Sc3N@C80 fullerene and Sc3N@C80PCBM fullerene derivate within the density functional formalism. Different surface terminations and orientations of the methyl ammonium are examined for binding of the fullerene layer. Our calculated …

Dedicated Hardware For Machine/Deep Learning: Domain Specific Architectures, Angel Izael Solis

Open Access Theses & Dissertations

Artificial intelligence has come a very long way from being a mere spectacle on the silver screen in the 1920s [Hml18]. As artificial intelligence continues to evolve, and we begin to develop more sophisticated Artificial Neural Networks, the need for specialized and more efficient machines (less computational strain while maintaining the same performance results) becomes increasingly evident. Though these “new” techniques, such as Multilayer Perceptron’s, Convolutional Neural Networks and Recurrent Neural Networks, may seem as if they are on the cutting edge of technology, many of these ideas are over 60 years old! However, many of these earlier models, at …

Spectroscopic Analysis Of Calcium Oxalate Kidney Stone Inhibition By Nordihydroguaiaretic Acid (Ndga), Mahendra Subedi

Open Access Theses & Dissertations

This current study provides information regarding the inhibition of calcium oxalate type of kidney stones by the use of nordihydroguaiaretic acid (NDGA). Around 80% of kidney stones found in patients are principally made of calcium oxalate and calcium phosphate. NDGA is an antioxidant compound that is chemically extracted from the desert bush Larrea tridentata. This work is a logical continuation of a previous research, where different concentrations of Larrea tridentata extract were used for such inhibition. Size and morphological changes from a calcium oxalate monohydrate (COM) structure to a calcium oxalate dihydrate (COD) structure were previously reported.

In the current …

A Study Of Solvent Effects On The Ground And Excited States Of Endohedral Tri-Scandium Nitride C80 Fullerene Coupled With Zinc Phthalocyanine And Metal-Free Phthalocyanine Using Dft-Pcm Method, Timilsina Prasad Timlsina

Open Access Theses & Dissertations

The photovoltaic active materials composed of endohedral metafullerene and phthalocyanine derivatives are known as excellent electron donor-acceptor pairs. The tri-metallic nitride endohedral C80 fullerene exhibits high absorption coefficients in the visible region of the spectrum and has similar electron-accepting abilities as that of C60 fullerene, which can allow for higher efficiencies in OPV devices. In this study, we examine the effect of solvent on the charge transfer excitation energies of Sc3N@C80-ZnPc and Sc3N@C80-H2Pc donor-acceptor molecular complexes. Three different solvents with different polarity - water, toluene, and acetone are used. The solvent is modeled as a polarizable continuum as implemented in …

Low-Valent Synthons Of Titanium : Investigations On Structure-Reactivity Relationships, Rolando Aguilar

Open Access Theses & Dissertations

Strategies for the functionalization of abundant, small molecules into products with added value provide a powerful approach to address environmental sustainability issues. Dinitrogen (N2), and carbon oxides (CO, CO2), are examples of the ample, yet, underutilized atmospheric feedstock of nitrogen and carbon building blocks to produce a variety of chemicals. Although, potentially valuable, small molecules are inert under most conditions, and as such, their industrial activation often requires heterogeneous catalysts operated under high pressures (200 atm) and temperatures (450-600 ºC).

To this end, great efforts in synthetic inorganic chemistry have been devoted to the generation of well-defined and highly reactive …

Robust Statistical Inference For The Gaussian Distribution, Andrews Tawiah Anum

Open Access Theses & Dissertations

The aim of robust statistics is to develop statistical procedures which are not unduly influenced by outliers or observations that are not representative of the underlying "true" data generating process. This thesis focuses on an estimator with this characteristic. The divergence function is introduced in Chapter 2 with the sole aim of taking the function f to be the univariate normal distribution and α - [0, 1]. The estimator fails when we rely on the classic Newton's method to converge to the minimum of the density power divergence (MDPD) function. There is a tendency of such estimator never to approach …

Energy Efficiency And Fatigue Failure On Gears And Bearings For Processing Rebar Steel, Jesus Gabriel Garcia

Open Access Theses & Dissertations

Steel industry is a major emitter of air pollutants, a leading industrial consumer of water, a minor source of contaminated liquids, a massive producer of solid waste, and a significant source of CO2. The objective on this thesis work is to minimize the greenhouse gas emissions when processing steel. Gears and bearings were evaluated based on their performance when exposed to cyclic stresses. The importance for having a proper set up on rolling mills to increase efficiency for processing rebar steel has been detailed on paper. In contrast, mechanical vibration has been measured on gears and bearings to determine efficiency …

A Novel Set Of Weight Initialization Techniques For Deep Learning Architectures, Diego Aguirre

Open Access Theses & Dissertations

The importance of weight initialization when building a deep learning model is often underappreciated. Even though it is usually seen as a minor detail in the model creation cycle, this process has shown to have a strong impact on the training time of a network and the quality of the resulting model. In fact, the implications of choosing a poor initialization scheme range from leading to the creation of a poorly performing model to preventing optimization techniques (like stochastic gradient descent) from converging.

In this work, we introduce and evaluate a set of novel weight initialization techniques for deep learning …

Non Linear Optics For Materials Fabrication And Medical Instrumentation, Aurelio Paez

Open Access Theses & Dissertations

Two-photon absorption is a nonlinear optical process where two photons are absorbed by a molecule simultaneously. The probability of this quantum phenomenon is proportional to the quadratic excitation of light intensity. It has many applications in biomedical and materials research, such as two-photon fluorescence microcopy. The first project is to apply two-photon absorption induced bond cleavage in photoreactive materials for engineering 3D tissue scaffolds. The major challenge for growing thick 3D tissues is the lack of vasculature, where nutrients and oxygen can be delivered to the growing cells. Our collaborators have synthesized a novel polypeptide that is composed of 34-mer …

Quasi-Harmonic And Anharmonic Entropies In Transition Metals, Bimal K C

Open Access Theses & Dissertations

Density functional theory (DFT) employing the quasi-harmonic approximation (QHA) is a robust method for evaluating thermal properties of solids. In the case of transition metals however, the method yields high values of the thermal pressure when compared to experimental data or with more direct methods like quantum-molecular dynamics (QMD) simulations. Surprisingly, there has not been to date, a systematic study aimed at understanding the reasons for these large discrepancies, particularly at low temperature, i.e. below the Debye temperature of the solid. Using Tantalum as a test model for which a lot of experimental data exist, thermal properties were evaluated employing …

Study Of Multielectron Redox Chemistry In Bimetallic Complexes And Metal-Free Macrocycles, Nancy Rodriguez Lopez

Open Access Theses & Dissertations

Multielectron redox chemistry is fundamental for the activation of small molecules (e.g. H2O, CO2, CO, N2). Although these processes are of great importance, they are not well understood. Unravelling the mechanisms of electron transfer and its principles is essential for the design and development of efficient catalysts. Our approach towards the understanding of multielectron redox chemistry includes theoretical study of mechanistic pathways in the hydrogen evolution reaction (HER) by metal-free porphyrinoids, the study of electronic communication in non-symmetric multimetallic two-state models (D–B–A) and the tuning of the electronic properties of bimetallic systems (Mo, and Au) by ligand control.

In Chapter …

Inverse Gaussian Ornstein-Uhlenbeck Applied To Modeling High Frequency Data, Emmanuel Kofi Kusi

Open Access Theses & Dissertations

With about 226050 estimated deaths worldwide in 2010, earthquake is considered as one of the disasters that record a great number of deaths. This Thesis develops a model for the estimation of magnitude of future seismic events.

We propose a stochastic differential equation arising on the Ornstein-Uhlenbeck processes driven by Inverse Gaussian (a,b) process. Inverse Gaussian (a,b) Ornstein-Uhlenbeck processes offer analytic flexibility and provides a class of continuous time processes capable of exhibiting long memory behavior. The stochastic differential equation is applied to geophysics and financial stock market by fitting the superposed Inverse Gaussian (a,b) Ornstein-Uhlenbeck model to earthquake and …

Petrophysical, Geostatistical And Geo-Spatial Analysis Of Round Top Mountain Rhyolite (Hudspeth County, West Texas, Usa), Lorraine Marie Negron

Open Access Theses & Dissertations

This project consists of three separate projects that all investigate Round Top Mountain, a rhyolite laccolith located in Sierra Blanca, west Texas in Hudspeth County (U.S.A). The three projects will explore and analyze the petrophysical, geostatistical and geo-spatial aspects of this unique deposit.

Project 1:

This petrophysical study examines the porosity and micro-permeability of the Round Top rhyolite at a scale, roughly 5 to 10 mm or pebble sized, similar to anticipated heap leach crush sizes. Large voids and fluid paths, such as faults and joints in the massive rock (meter to km scale, boulder to outcrop size), are not …

Decision Making Under Uncertainty With Applications To Geosciences And Finance, Laxman Bokati

Open Access Theses & Dissertations

In many practical situations, we need to make a decision. In engineering, we need to decide on the best design of a system, and, for existing systems â?? on the best control strategy. In financial applications, we need to decide what is the best way to invest money. In geosciences, we need to decide whether we should explore a possible mineral deposit â?? or whether we should perform more experiments and measurements (and what exactly). In some cases, we can compute the exact consequences of each decision - e.g., if we are controlling a satellite. However, in many other cases, …

Synthesis Of Advanced Functional Nanomaterials For Sustainable Water Treatment Technologies, Md Tariqul Islam

Open Access Theses & Dissertations

Water is the most essential resource for the sustenance of life. Water is also necessary for agriculture, industry, household, and environmental conservation. However, due to large population growth and industrial expansion, access to clean water is becoming increasingly difficult around the world. Current water treatment technologies have not changed in over one hundred years and require a large infrastructure due to their low efficiencies and large-scale needs. In this context, the utilization of advanced functional nanomaterials and the adaptation of nanotechnology could potentially allow for miniaturizing water treatment and develop de-centralized solutions for rural areas. This Dissertation presents the design, …

Fishers' Ecological Knowledge And Stable Isotope Analysis: A Social-Ecological Systems Approach To Endangered Species Conservation, Kathryn Rose Wedemeyer-Strombel

Open Access Theses & Dissertations

Identifying developmental habitat is essential for understanding population structure and species resiliency, especially for critically endangered species. In long-lived, oceanic, migratory animals such as sea turtles, elucidating developmental grounds is particularly difficult. When data are deficient or challenging to acquire, scientists often lean towards traditional quantitative methods when a social-ecological systems approach could better provide crucial baseline data and guiding information. Fishers’ ecological knowledge (FEK), the combination of experiential and culturally transmitted knowledge, is expert knowledge and should be treated as such. In 2008, FEK led to the “rediscovery” of the critically endangered eastern Pacific (EP) population of hawksbill sea …

Interactions Of Bacterial Communities With Hydrous Sulfate Minerals In Water-Restricted Gypsic Environments: A Case Study Based In The White Sands National Monument, Brandon Nicholas Lajoie

Open Access Theses & Dissertations

Microbial communities have been commonly found to survive and thrive in arid to hyper-arid gypsic environments that are considered hostile to most other forms of life. The mechanisms through which microbes have conquered these harsh environments remain poorly understood. Here I hypothesize that the microbial communities in water-restricted gypsic settings could benefit in terms of energy and water sources via their interactions with the abundant hydrous sulfate minerals [i.e., gypsum (CaSO4·2H2O)] that build up these niches. Gypsum is of high bio-relevance because its sulfate component may be used as electron acceptor by sulfate-reducing bacteria and the crystallization water may be …

Study Of D-Electron Systems With Fermi-Lowdin Orbital Self-Interaction Correction, Prakash Mishra

Open Access Theses & Dissertations

Density Functional Theory (DFT) is one of the very popular and versatile methods for calculations to study electronic structure, and the accuracy of DFT depends on the approximation used in the exchange-correlation functional. One of the known problems with the approximation is that the widely used density functional approximations (DFA) suffer self-interaction errors. Systems with d-electrons such as transition metal oxides often show deviation of DFT predicted behavior from experimental result. SIE tends to unphysically lower the energies of fractionally occupied state which leads to deviation from piece-wise linear behavior of total energy between two integer occupations. This leads to …

Sequence Stratigraphy, Diagenesis, And Depositional Facies Of An Exposed Megaflap: Pennsylvanian Hermosa Group, Gypsum Valley Salt Wall, Paradox Basin, Colorado, Kyle Thomas Deatrick

Open Access Theses & Dissertations

Outcrop exposures mostly of the Pennsylvanian Honaker Trail Formation provide a 2 km strike-oriented view of a megaflap on the southwestern flank of the Gypsum Valley salt wall, Paradox Basin, Colorado that serves as an outcrop analog for megaflaps recently drilled unexpectedly in the Gulf of Mexico and other salt basins worldwide. The near vertical (80-90°) stratal panel comprises a 60 m thick succession of non-evaporite facies of the Pennsylvanian upper Paradox Formation, overlain by a 117 m section of cyclic shallow marine carbonates and siliciclastics of the Honaker Trail Formation. Near vertical upper Paradox and Honaker Trail strata are …

Confidence Intervals For The Expected P-Value, Emmanuel Kofi Abrefa

Open Access Theses & Dissertations

The p-value is widely used in many application fields. In common practice, a scientific finding is deemed statistically significant if its resultant p-value is less than a pre-specified significance level, for example α = 0.05, albeit many statistically significant results are not reproducible in new studies. Mixed reasons including misuses, abuses, misunderstanding and misinterpretation arouse intensive debates and conservatives around the p-value from time to time over the years. Yet no reasonable solutions have been proposed. In this research, we make efforts to close the gap by advocating the use of confidence level for the expected p-value p0. This allows …

A Coupled Modeling Framework For Allocation Design In Land-Use And Land-Cover Changes To Optimize Biofuel Feedstock Production, Ana C. Cram

Open Access Theses & Dissertations

Environmental awareness has increased the demand for renewable energy. Notably, the production of biofuels from feedstock is gaining interest as a viable measure to reduce fossil fuels consumption. Nevertheless, it is crucial to identify the trade-offs between bioenergy crop cultivation and the environmental impact on land, water, and atmosphere.

Intensifying biofuel cultivation trigger effects associated with Land Use and Land-use-change, which are complex to assess. While hydrological models had been used to investigate the environmental impacts of land-use changes on water and soil quality, their quantitative assessment is often incomplete. Changes in land use and agricultural activities also contribute to …

Novel Maximum Entrophy Method For The Average Survival Time Differences Between Two Groups, Joscelyne Guzman - Gonzalez

Open Access Theses & Dissertations

We suggest a Maximum Likelihood estimator for the Average Survival Time Difference between two groups, based on the extra time in which should be added to one group to produce the maximum entropy of the result. The estimator is calculated only from time to event data, does not assume hazard proportionality and provides directly the magnitude of the clinical differences between the groups. Our Monte Carlo simulations show that, even at low sample numbers the estimator is a reliable predictor for the clinical differences between the groups, and therefore can be used to estimate from preliminary data whether or not …

Ibuprofen As A Probe Of Lipid Metabolism, Jose Antonio Rosales

Open Access Theses & Dissertations

The hypothesis that deracemization of racemic ibuprofen (IBU) occurs via the enolization of a Candida rugosa lipase (CRL)-ibuprofen ester (Scheme 1.6.2) was disproven by reacting racemic IBU under the conditions that were used to deracemize ibuprofen methyl ester (IME), namely pH 7.6. At pH 7.6, IME through IBU butyl esters were not formed in-situ and racemic IBU was not deracemized by reacting the corresponding primary alcohol with racemic IBU in the presence of CRL.

At pH 7.6, hexyl through dodecyl IBU esters were formed in-situ by reacting the corresponding primary alcohol with racemic IBU in the presence of CRL. The …

A Quantitative Assessment Of Trace Metals In Subsurface Soils And Groundwater In Agricultural Fields Of El Paso, Texas, Emmanuel Sosa

Open Access Theses & Dissertations

Intensive agricultural practices such as irrigation, application of pesticides and the use of fertilizers, as well as contamination from urban settings and industrial activities contribute to the input of trace metals onto soils and groundwater. Consequentially, biological uptake and accumulation concentrate these toxic metals in fruits, vegetables, and grains that will be used for human consumption. In southern New Mexico and western Texas, cropland is developed along the Rio Grande valley. These farmers are concerned about the quality of their irrigation water and soils in order to produce adequate crops and maintain healthy soils to maximize revenue. To evaluate loading …

Inverse Gaussian Ornstein-Uhlenbeck Applied To Modeling High Frequency Data, Emmanuel Kofi Kusi

Open Access Theses & Dissertations

With about 226050 estimated deaths worldwide in 2010, an earthquake is considered as one of the disasters that records a great number of deaths. This thesis develops a model for the estimation of magnitude of future seismic events.

We propose a stochastic differential equation arising on the Ornstein-Uhlenbeck processes driven by IG(a,b) process. IG(a,b) Ornstein-Uhlenbeck processes offers analytic flexibility and provides a class of continuous time processes capable of exhibiting long memory

behavior. The stochastic differential equation is applied to geophysics and financial stock markets by fitting the superposed IG(a,b) Ornstein-Uhlenbeck model to earthquake and financial time series.

On The Performance Of Variable Selection And Classification Via Rank-Based Classifier, Md Showaib Rahman None Sarker

Open Access Theses & Dissertations

In high-dimensional gene expression data analysis, the accuracy and reliability of cancer classification and selection of important genes play a very crucial role. To identify these important genes and predict future outcomes (tumor vs. non-tumor), various methods have been proposed in the literature. But only few of them take into account correlation patterns and grouping effects among the genes. In this article, we propose a rank-based modification of the popular penalized logistic regression procedure based on a combination of l1 and l2 penalties capable of handling possible correlation among genes in different groups. While the l1 penalty maintains sparsity, the …

Mineral Exploration Investigation In The Northern Sierra Madre Occidental, Mexico, Labdan Nijr Alqahtani

Open Access Theses & Dissertations

The Sierra Madre region is rich in mineralized deposits, but it is hard to access because of the rugged terrain. Remote sensing and GIS can help in mineral exploration and regional structural analysis. The purpose of this project is to study linear, curvilinear, arcuate, and circular features in the Sierra Madre Occidental of Mexico in order to improve exploration possibility. It is of great interest to know the relationship between lineament intersections, caldera features because of the location of potential mineral occurrences. In this study, 4,445 lineaments were mapped manually using directional filters applied to satellite images. A total of …

Geophysical Studies Of The Three Sisters Andesite, West El Paso, Texas, Alexander D'Marco Garcia

Open Access Theses & Dissertations

The Three Sisters andesite intrusion is part of series of three small igneous bodies that crop out in western El Paso to the north of the more extensive intrusions found on the University of Texas at El Paso campus and at Mount Cristo Rey. These Oligocene age intrusions are believed to form part of a deeper, more extensive igneous body that may lie beneath much of western El Paso and the southern Mesilla Valley. I used several geophysical techniques to determine the size and shape of the Three Sisters intrusion to better understand its connection to other andesite outcrops and …