Digital Commons Network^™

Investigation Of The Natural Degradation Of Selected Endocrine Disrupting Compounds In Wastewater, Toni Carrick

Open Access Theses & Dissertations

Endocrine disrupting compounds (EDCs) are a class of compounds that are of concern for their potentially adverse effects on fish, wildlife, and humans. They can cause developmental and reproductive anomalies at concentrations in the low ppb to ppt levels. Studies have shown the primary route of exposure of EDCs within the environment is through the discharge of effluent wastewater. Removal efficiencies of wastewater treatment plants have been studied extensively, however, in rural or developing areas, which often lack secondary or tertiary wastewater treatment, little is known about the stability of these compounds and the rate at which they degrade in …

Does Low-Level Arsenic Exposure Predict Blood Pressure In Children?, Tania Angelica Mayorga

Open Access Theses & Dissertations

Background & Significance: Inorganic arsenic is a heavy metal naturally found in soil and human exposure to this heavy metal causes adverse effects. Exposure risks are particularly high in developing children. Arsenic is mainly found in bedrock. It is also a by-product of smelting, it is used in cement production, and historically is has been found in crop pesticides. Among other ill-effects, arsenic exposure in humans can cause respiratory diseases, peripheral neuropathy and liver fibrosis. In particular arsenic has been shown in many studies to be a contributing factor in the risk for hypertension in adults however no studies have …

High Performance Computing In Air Quality Models An Their Applications, Roberto A. Perea

Open Access Theses & Dissertations

High Performance Computing has become an important tool for many applications and services in the areas of Air Quality research. One important aspect is the use of computational technology in simulation and modeling of complex Air Quality models which makes it affordable in terms of data analysis, processing and speed. For this Dissertation, three projects using Air quality models were developed using high performance computing.

For the first project, ozone concentrations for the Paso del Norte Region are simulated using air quality models and compared against experimental data. For the second project, the Development of models and optimization of codes …

Processing And Property Evaluation Of Tungsten-Based Mixed Oxides For Photovoltaics And Optoelectronics, Mirella Vargas

Open Access Theses & Dissertations

Tungsten Oxide (WO3) films and low-dimensional structures have proven to be promising candidates in the fields of photonics and electronics. WO3 is a well-established n-type semiconductor characterized by unique electrochromic behavior, an ideal optical band gap that permits transparency over a wide spectral range, and high chemical integrity. The plethora of diverse properties endow WO3 to be highly effective in applications related to electrochromism, gas sensing, and deriving economical energy. Compared to the bulk films, a materials system involving WO3 and a related species (elements or metal oxides) offer the opportunity to tailor the electrochromic response, and an overall enhancement …

Comparison Of Blood Lead Levels Between Children In An Urban Setting And Children In A Rural Setting, Juan Manuel Alvarez

Open Access Theses & Dissertations

Environmental heavy metal exposure is a public health problem that is of great concern because it is highly toxic for children. The urban setting in downtown El Paso is historically known to be contaminated through various sources of contamination of heavy metals. The goal of this study was to compare whether children in a historically contaminated urban downtown area had significantly increased levels of lead exposure as compared to children in a demographically similar rural area approximately 20 miles north of the urban center, while controlling for gender and age. Cadmium and mercury were also measured for comparison purposes. It …

Short-Term Forecasting Analysis Of Municipal Water Demand In El Paso, Texas, Alejandro Ceballos

Open Access Theses & Dissertations

Short-term water demand forecasts inform decisions regarding budgeting, rate design, water supply system operations, and effective implementation of conservation policies. This study develops a Linear Transfer Function (LTF) forecasting model for El Paso, Texas, a growing city located in the desert Southwest region of the United States. The model is used to generate monthly-frequency out-of-sample simulations of water demand for periods when actual demand is known. To measure the accuracy of the LTF projections against viable alternatives, a set of benchmark forecasts is also developed. Both descriptive accuracy metrics and formal statistical tests are used to analyze predictive performance. The …

Novel Endohedral Derivatives Of Sc3n@C2n (N = 34, 40) And Unique Tether Controlled Bis-Functionalization Of Fullerenes, Maira Raquel Ceron Hernandez

Open Access Theses & Dissertations

Since the discovery of fullerenes in 1985, their exohedral functionalization has been necessary to increase their solubility and explore their properties and potential applications in materials science and medicinal chemistry. This Thesis provides a short overview of the importance of electronic, size and shape complementarity in determining the structures of specific endohedral fullerene compounds. This is followed by a description of a new method for the separation of scandium nitride endohedral fullerenes Sc3N@C2n (n = 34, 39 and 40), and their monofunctionalization.

We also present the regioselective synThesis of easily isolable bis-derivatives of C60, C70, and M3N@Ih-C80 (M = Sc, …

A Pilot Study Of Arsenic In Young Children From Two Rural West Texas Communities: Blood Levels, Household Water Levels, And Behavioral Outcomes, Michelle Del Rio

Open Access Theses & Dissertations

Background & Significance: Heavy metals have been identified as a child health hazard because children are highly vulnerable to the effects of exposure, which can be physical, cognitive, and behavioral. Levels of arsenic (As) greater than the EPA Maximum Contaminant Level (10μg/L) were identified in some household water samples in two rural west Texas communities located within 20 miles of the U.S.-Mexico border by a Health Impact Assessment conducted in 2013 (Hargrove, Juarez-Carillo, & Korc 2015). Whether home water samples predicted child blood As levels needed to be examined. Since lead (Pb) is another common heavy metal contaminant in the …

Exploratory Study Of Seasonal Indoor Bioaerosols And The Associated Health Outcomes In Low-Income Communities In El Paso, Texas, 2014, Eric Martinez

Open Access Theses & Dissertations

Introduction: Structural degradation, moisture levels, and building failures can influence poor indoor air quality and create a good environment for bioaerosols. People spend much of their time indoors and can potentially be exposed to these bioaerosols. Several studies have correlated exposures to high concentrations of bioaerosols to various health problems, severe allergies, asthma, or other respiratory illness. Objectives: The objectives of this study are to describe bioaerosol concentrations, meteorological factors, and health outcomes during the summer and fall seasons; characterize bioaerosols (bacteria and fungi) collected in low-income communities; compare bioaerosol concentrations by season; compare meteorological factors to bioaerosol concentrations by …

Reaction Of Liquid Aluminium- Samarium Alloys With B4c At Ultra High Temperatures, Sanjay Shantha-Kumar

Open Access Theses & Dissertations

Reactive studies between a packed bed of B4C and Al-Sm-Me (Me = Ti, Zr, Hf) alloy melts were carried out under a pseudo-isopiestic thermodynamic system. A graphite enclosure isolated the system under a temperature gradient with one end reaching temperatures greater than 1800 K and the opposite end of the graphite enclosure contains liquid Al with temperatures approximating 950 K. The liquid Al establishes an oxygen potential to control oxidation of very reactive elements (i.e., Al, Sm and Ti). The Al-Sm-Me alloy infuses into a packed bed of B4C reacting exothermically to form borides and carbides depending on the thermodynamic …

Using The Wrf Model To Simulate The Playa Breeze Over Dugway Proving Ground, Daniela Maria Spade

Open Access Theses & Dissertations

The aim of this model and observation based study is to investigate the Advanced Research Weather Research and Forecasting Model's (WRF-ARW, although WRF from hereout) ability to simulate the three-dimensional structure of playa breezes and drainage flows occurring in Dugway Proving Ground, Utah using sub-km nesting in addition to improved land use and terrain datasets (as compared to the default datasets provided with WRF), in addition to studying the diurnal cycle and interactions between the playa breeze and drainage flows. A playa breeze is a thermally forced air circulation system that develops near the edge of playas, which have properties …

Single And Multiple Objective Biomass-To-Biofuel Supply Chain Optimization Considering Environmental Impacts, Claudia Evangelina Valles Sosa

Open Access Theses & Dissertations

Bioenergy has become an important alternative source of energy to alleviate the reliance on petroleum energy. Bioenergy offers diminishing climate change by reducing Green House Gas Emissions, as well as providing energy security and enhancing rural development. The Energy Independence and Security Act mandate the use of 21 billion gallons of advanced biofuels including 16 billion gallons of cellulosic biofuels by the year 2022. It is clear that Biomass can make a substantial contribution to supply future energy demand in a sustainable way. However, the supply of sustainable energy is one of the main challenges that mankind will face over …

An Assessment Of The Role Of Roads In Population Demography And Genetic Structuring In Two Species Of Lizards In The Northern Chihuahuan Desert, Kevin Floyd

Open Access Theses & Dissertations

Roads can fragment habitat and increase mortality rates of wildlife, potentially reducing population sizes and gene flow, which in turn can reduce genetic diversity through genetic drift. Although negative road impacts have been found in a variety of taxa, not all species are impacted. For instance, species that move less and rarely encounter roads and those that avoid the roads are predicted to not be negatively affected. Yet tests of these predictions are uncommon, especially for reptiles and particularly lizards. Side-blotched lizards (Uta stansburiana) are small sit-and-wait predators, while the larger marbled whiptails (Aspidoscelis marmorata) are active foragers. Their responses …

Constructing Negotiated Meaning And Knowledge For The Sol Y Agua Project's Role-Playing Adventure Game Focused On Sustainability Problems In The El Paso-Rio Grande Area, Claudia Chihiro Santiago

Open Access Theses & Dissertations

Video games that address environmental sustainability issues could engage students. However, video games make simplifications and establish idealistic expectations that do not resemble real life sustainability challenges and settings. Game developers and scholars believe that depicting the complexity of the real world could help video games become effective educational tools. They call for additional procedures that incorporate information from actual settings and real life situations. Furthermore, scholars have argued that video games addressing sustainability issues can be improved or made more meaningful with the participation of youth from underrepresented populations, e.g., Latinos. The Sol y Agua project at The University …

Triphenylamine-, Porphyrin- And Fullerene-Based Derivatives For Photovoltaic And Other Applications, Danisha Marie Rivera Nazario

Open Access Theses & Dissertations

Proper collection of charges at the electrodes is an important process in organic solar cells. Interfacial layers between the electrodes and the photoactive layer have been design to improve charge collection and ohmic contacts. The most studied interfacial layer between the anode and the photoactive layer is the negatively charged polymer poly(3,4-ethylendioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), that possesses good hole transporting ability. However, inhomogeneities at the surface of the electrode after deposition of the polymer lower the stability and performance of the OPV devices. Triphenylamine (TPA) derivatives have received increased attention in the organic solar cells (OSCs) field because of their favorable light …

Salt And Mineral Recovery From High Salinity Waters, Osvaldo Alejandro Broesicke

Open Access Theses & Dissertations

Natural salt springs in the Salt Fork Basin in Crosby County, Texas, result in the natural salt pollution of the Brazos River, rendering it unusable for most potable purposes. Previous research indicates that by intercepting the source of the pollution, water quality of the Brazos River can be greatly improved. This paper investigates and assesses two strategies for salt and mineral recovery using natural brine collected from the Salt Fork Basin, the first of which is presented in a separate work.

The research described in this paper evaluates the potential of a desulfation, soda-caustic softening, acidification/decarbonation, and evaporation process to …

Trace Element Behavior During Coal Combustion: Insights From Cadmium And Zinc Isotope Analysis, Fotios Fouskas

Open Access Theses & Dissertations

Due to its low cost and abundance, coal has been pervasively used in recent decades to meet large energy demands worldwide. Coal combustion provides the dominant electrical source in the U.S and produces over 100 million tons of coal combustion products (CCPs) per year domestically. The disposal/beneficial use of CCPs has the potential to release toxic trace elements, including cadmium (Cd) and zinc (Zn), into the environment. High temperature combustion of coal changes both physical states and chemical properties of Cd and Zn compounds in CCPs. Related processes such as evaporation and condensation, can lead to mass-dependent fractionation of Cd …

High Temperature Helical Tubular Receiver For Concentrating Solar Power System, Nazmul Hossain

Open Access Theses & Dissertations

In the field of conventional cleaner power generation technology, concentrating solar power systems have introduced remarkable opportunity. In a solar power tower, solar energy concentrated by the heliostats at a single point produces very high temperature. Falling solid particles or heat transfer fluid passing through that high temperature region absorbs heat to generate electricity. Increasing the residence time will result in more heat gain and increase efficiency. A novel design of solar receiver for both fluid and solid particle is approached in this paper which can increase residence time resulting in higher temperature gain in one cycle compared to conventional …

The Impacts Of Water Availability On Macroinvertebrate, Ector Matias Martell

Open Access Theses & Dissertations

In many regions around the world climate is changing and biotic communities are changing with it. In areas like the southwestern U.S., drought is one of the major sources of disturbance. Although droughts are an integral part of the natural hydrological cycles, they can have devastating effects on freshwater ecosystems when disrupted by extended periods of drought, resulting in changes to the structure and function of biotic communities. In this study, we surveyed four streams in the Sacramento Mountains of New Mexico from 2010 to 2014: Agua Chiquita, Rio Peñasco, Wills Creek, and the Sacramento River; These years encompassed an …

Latina/O High School Students' Standpoint On Environmental Justice In A Border Community: A Phenomenological Study, Cynthia Christina Ontiveros

Open Access Theses & Dissertations

This qualitative research is a transcendental phenomenology seeking to understand Latin@ high school students’ perceptions and standpoints as they participated lessons that addressed border environmental justice issues in an underrepresented, marginalized community. Seven students from Borderland High School, enrolled in a senior level course, Environmental Science, participated in the study which focused on their experiences in an environmental justice air quality thematic unit built around the complex issues surrounding a local refinery, American Smelting and Refining Company (ASARCO). The study analyzed the meaning students made and their standpoints regarding the impact of the factory and its one-hundred year history polluting …

Heat Absorption Analysis By Falling Particles At High Temperatures For Concentrating Solar Power Systems, Arturo Sepulveda Fernandez

Open Access Theses & Dissertations

High temperature Heat Transfer Fluid (HTF) with Thermal Energy Storage (TES) for the Concentrated Solar Power (CSP) technology can provide a large and relatively cheaper storage option, as opposed to limited and expensive electrical battery storage with PV technology, and hence, it has potential to maintain a constant production when no sunlight is available. Research of material like aluminum, silicon, graphite could be potential candidates to work as thermal energy storage. Currently, nitrate and chloride molten salts are widely used as the TES medium for a CSP plant. However, molten salt, especially chlorides, must be handled carefully at high temperature …

Monitoring And Understanding Decadal Scale Changes In Hydrology, Productivity And Carbon Balance In Arctic Tundra Ponds, Christian Gerardo Andresen

Open Access Theses & Dissertations

The Arctic is known for containing large stocks of soil organic carbon, which exists frozen in permafrost in a greenhouse inert state. With predicted future warming in these high northern latitudes, the mobilization of stored soil organic carbon and release to the atmosphere may increase and induce further positive climatic feedbacks. Previous studies have shown that Arctic wetlands and ponds cover a large percentage of the Arctic Coastal Plain and contribute large amounts of carbon to the atmosphere; however, it remains largely unknown how these systems are responding to a warming climate and how this change will impact regional carbon …

Nanoceria Exposure To Kidney Beans (Phaseolus Vulgaris): Implications On Plant Physiology, Nutrition And Their Transfer To Next Trophic Level, Sanghamitra Majumdar

Open Access Theses & Dissertations

Previous studies investigating the effects of cerium oxide nanoparticles (nanoceria, nCeO2) on plants have primarily focused on the physiological and biochemical changes at early growth stages. Comprehensive information on the effects of nCeO2 through the entire life cycle of plants and the nutritional quality of the edible tissues is limited. No studies have been reported on the interactions between nCeO2 and common beans (Phaseolus vulgaris). Common beans are leguminous crops, which are societally important due to their nutritional benefits. The beans are rich in proteins and essential nutrients like folate, iron, zinc, molybdenum and magnesium, and are consumed worldwide. This …

The Impacts Of Health Status And Exposure To Environmental Toxins On Children's Grade Point Average In El Paso, Texas, Stephanie Elizabeth Clark

Open Access Theses & Dissertations

Studies in the US have found that both exposure to environmental toxins and children's general health status negatively impact children's academic achievement. This Thesis will be made of up two papers. The first examines the impact of exposure to residential air toxins from a variety of sources on student's academic achievement and the second paper incorporates a measure of children's general health status into the statistical model from the first paper. This Thesis employs National Air Toxics Assessment (NATA) risk estimates from a variety of sources and individual-level data collected through a mail survey of fourth and fifth grade school …

Aerosol Physical And Chemical Properties Over Tropical Atlantic Ocean, Elsa Castillo

Open Access Theses & Dissertations

The atmospheric aerosol mass size distributions, modal characteristics, and a comparative analysis of the characteristic of PM2.5 versus trace gases: CO, O3, and SO2 over tropical Atlantic Ocean have been evaluated for Nov-Dec 2013. This study took place during the IX AEROSE expedition while the National Oceanic and Atmospheric Administration (NOAA) research vessel Ronald H. Brown traveled south along 23°W between 3°N and 5°S.

Aerosol mass size distributions were measured directly with a California Instruments Model PC-2H Quartz Crystal Microbalance (QCM). The corresponding values of average mass for accumulation, nuclei and coarse mode obtained were: 0.00124±0.00077, 0.00506±0.00254, and 0.00176±0.00114 μg/m …

Study Of A Directly Heated Oxy-Fuel Supercritical Power Generation System, A S M Arifur Rahim Chowdhury

Open Access Theses & Dissertations

The Directly heated supercritical oxy-fuel gas turbines have the potential to become an important addition to current power generation systems. They provide a higher thermal efficiency and more effective carbon capture techniques than existing gas turbines. Due to the higher density of the working fluids, the turbomachinery size in these systems can be reduced significantly; this will facilitate to minimize the operational cost. To achieve supercritical working fluid at the turbine inlet combustion needs to be conducted under enormous amounts of pressure; these values are is about 10 times those found in the present gas turbines. Additionally, existing material operational …

Wind Farm Optimization Using Evolutionary Algorithms, Carlos Marco Ituarte-Villarreal

Open Access Theses & Dissertations

In recent years, the wind power industry has focused its efforts on solving the Wind Farm Layout Optimization (WFLO) problem. Wind resource assessment is a pivotal step in optimizing the wind-farm design and siting and, in determining whether a project is economically feasible or not. In the present work, three (3) different optimization methods are proposed for the solution of the WFLO: (i) A modified Viral System Algorithm applied to the optimization of the proper location of the components in a wind-farm to maximize the energy output given a stated wind environment of the site. The optimization problem is formulated …