Engineering Commons^™

From Screening To Risk: Assessment Of Potentially Toxic Elements In Children's Toys Along The El Paso, Tx, U.S.A.-Ciudad Juarez, Chih, Mex Border Region, Jesus Rodriguez-Loya

Open Access Theses & Dissertations

Children are uniquely vulnerable to potentially toxic elements (PTEs), absorbing them more readily than adults and encountering them through the hand-to-mouth behaviors of early childhood. Exposure carries element-specific consequences: lead (Pb) impairs cognitive development with no established safe threshold; cadmium (Cd) damages the kidneys and reduces bone mineralization; arsenic (As) is a recognized carcinogen and developmental neurotoxicant; hexavalent chromium (Cr) is carcinogenic and induces allergic dermatitis; nickel (Ni) is the leading cause of allergic contact dermatitis in children; and excess zinc (Zn) disrupts copper absorption and causes gastrointestinal distress. Toys are a distinctive source of such exposure, yet none had …

Mitigating Clay Contamination In Field Sands To Prevent Early Age Failure In Asphalt Mixtures, Suhail Rashid Vaid

Open Access Theses & Dissertations

Field sands are commonly incorporated into hot mix asphalt (HMA) pavements due to their availability and cost-effectiveness compared to crushed aggregates, primarily to enhance workability. Their usage, however, is generally restricted to no more than 10% of the total aggregate content because of concerns regarding their potential negative influence on pavement performance. A major concern is the presence of deleterious clay particles, which can substantially affect the behavior of asphalt concrete (AC). This research explored how clay minerals influence AC performance by examining Superpave mixtures and characterizing both clay and sand properties. The methylene blue value (MBV) was employed to …

Calibration Of Low-Cost Pm2.5 Sensors Using Data Continuously Generated At A Reference Station In El Paso, Texas, Brenda Lizbeth Hernandez

Open Access Theses & Dissertations

Low-cost sensors (LCS) offer a cost-effective way to expand air-quality monitoring networks, but they require strong calibration methods to ensure reliable performance under changing environmental conditions. In this study, Clarity LCSs were co-located with a state reference monitor for 6 months to evaluate fixed-time (2-, 3-, 4-, and 6-week) and rolling (2- and 3-week) calibration approaches. A multivariate regression model using PM1, PM2.5, PM10, and relative humidity was used to generate calibration coefficients for a “base sensor.” Data from two additional sensors were normalized to the base unit using linear regression, and their calibration coefficients were applied across the network. …

Sustainable Disposal Of Pecan Shells, Jose Carlos Carrasco

Open Access Theses & Dissertations

Urbanization acceleration has increased the consumption of natural resources and carbon footprint, pushing the need for sustainable development. Even though various construction materials are needed for infrastructure development, the most commonly used material is Ordinary Portland Cement for strength (OPC) and durability, while sand is used as a filler in the mixes prepared with OPC. The main goal of this study is to find a sustainable substitute for sand, which is locally available and currently being placed in landfills. One such material is pecan shells, and a thorough analysis of the literature led us to investigate the possible use of …

Sustainable Agriculture Through Data-Driven Land And Soil Management For Rural Farming Communities, Peggy Clareece Discenza

Open Access Theses & Dissertations

This thesis aims to investigate sustainable farming practices by utilizing a database containing soil, weather, and water data. Additionally, it evaluates cropping strategies using a system that incorporates nutrient dynamics and environmental values. The objective is to monitor, develop predictive models, and assess the impact of both controlled and uncontrolled nutrient variables. This is achieved through the development of an algorithm that provides information on soil health based on datasets and land use, with a particular focus on residual values after harvesting for deeper analytical insights and interpretation. This study focuses on key nutrients, including pH levels, water availability, and …

A Blue Hydrogen Framework For Regional Energy Resiliency, Safwan Shafquat

Open Access Theses & Dissertations

High-pressure gasification is gaining attention as an emerging solution for sustainable energy production due to its potential to achieve higher efficiencies, improved syngas quality and smaller equipment footprints. High operating pressures and temperatures can increase the synergistic reactivity of biomass and organic materials, consequently enabling higher in situ tar reformation and ultimately reducing the number of gas treatment requirements. Additionally, higher operating pressures result in a more concentrated CO2 stream and reduce the amount of post-gasification compression requirements in the carbon capture and storage (CCS) unit, improving overall system efficiency. Plus, pressurized CO2 streams from the gasifier also provides routes …

How Active Rainwater Harvesting May Help Reduce Nuisance Flooding: Flood Analysis And Social Barriers To Adoption, Isabel Lopez

Open Access Theses & Dissertations

As urbanization continues to expand, fewer pervious surfaces are available to help reduce stormwater runoff from rainfall. The impacts of urbanization are becoming evident through sunny day flooding - flooding that occurs in areas not designated by the Federal Emergency Management Agency (FEMA) as flood zones. Nevertheless, water accumulates in low-lying areas and compromises street intersections and other parts of neighborhoods. Some methods can help alleviate the impacts of unexpected heavy rains, such as passive and active rainwater harvesting. As a pilot study, in a selected area in the northeast of El Paso, the level of adoption (e.g., what percentage …

An Approach For Verification Of Traffic Speed Deflectometer Measurements, Mahsa Beizaei

Open Access Theses & Dissertations

Recent research studies have shown the usefulness and applicability of Traffic Speed Deflectometers (TSD) in support of the network-level pavement management process. There are, however, no accepted procedures for verification and validation of the TSD measurements to be utilized by practitioners. To address this need, TSD measurements may be verified with the data obtained by widely accepted road-testing equipment, Falling Weight Deflectometer (FWD). In this study, TSD and FWD operations on pavement sections were simulated employing the finite layer approach which resulted in the development of a comprehensive database of pavement responses. Using the established numerical simulation database, theoretical relationships …

Nano-Engineered Soft Magnets: Potential Application In Water Treatment, Hyperthermia And Molecular (Organic) Magnets, Yohannes Weldemariam Getahun

Open Access Theses & Dissertations

Scrutinizing the remarkable and tunable properties of magnetic materials at a nanoscale size "There's Plenty of Room at the Bottom..." Richard Feynman, this study attempts to find sustainable solutions to some of the deteriorating environmental, health, and energy problems the world is encountering. Due to their simple preparation, surface adaptability, and tunable magnetic and optical properties, magnetic nanoparticles have been extensively investigated in water treatment, cancer therapy, data storage, and more. However, relying on non-reusable and chemical-based treatment agents in water, complex and costly cancer treatment procedures and molecular magnets that operate far below room temperature limited those attempts from …

Hybrid Model For Making Decision Methods In Wireless Sensor Networks Through Neuro-Fuzzy Inference System, Martha Lucia Torres

Open Access Theses & Dissertations

Considering the complexity and multiple alternatives for technology decisions in Wireless Sensor Networks (WSNs), a multicriteria selection method (MCDM) is an appropriate approach for choosing the best option in technical projects. Purely quantitative decision-making procedures have currently been created based on client requirements and recommendations from industry professionals in many domains. In this context, implementation and operational costs could be increasing due to technical problems and additional processes. In order to prevent future difficulties and obtain a more accurate technology selection, a new method was being developed to involve qualitative and quantitative parameters taken from real scenarios and technical literature …

Land Use/ Land Cover Change Patterns And Trends In Two Dryland Regions, Omar Sulaiman Belhaj

Open Access Theses & Dissertations

Development and climate change affect the environment in numerous ways and to varyingdegrees. This effect appears prominent and more influential in arid regions. Therefore, land use/ land cover in these regions experience profound changes such as plant cover decrease and extinction of some plant species. Also, land use/ land cover in these regions has critical impacts on the environment and its components, such as shrublands shrinking and losing the habitat of animal species. The degree of changes and effects reaches severe levels that become urgent to figure out the impacts and find solutions to stop or mitigate the negative consequences. …

Grid-Connected Renewable Energy Systems For Residential Hvac Load Management, Oscar Samuel Acosta

Open Access Theses & Dissertations

With an ongoing mission of utility operators to maintain a resilient and reliable power grid in the face of continuously increasing load demand, it is essential that advancements be made in developing both technology and methodology to help account for the increasing energy requirements. According to the U.S. Department of Energy (DOE) and Energy Information Administration (EIA), the residential end-use sector alone counted for 22% of all electricity used in the U.S. in 2020. Of this, approximately 32% of household electricity load is the direct result of air conditioning and space heating units (HVAC). One way to account for this …

Goes-16 Level 2 Land Surface Temperature Product-Filling For Cloud Masked Data, Guadalupe Ortega

Open Access Theses & Dissertations

The GOES-16 satellite ground segment team develops different levels of environmental products and makes them readily available to the public. The level 2 Land Surface Temperature (LST) product aims to provide a remote measurement of the Earth’s surface temperature every hour. LST is of fundamental importance to many aspects of the geosciences, for example, to study the Urban Heat Islands (UHI) effect. The product however, does not provide values for pixels where the satellite imager’s view is obstructed by clouds, as determined by a cloud mask intermediate product. The objective of this thesis is to estimate LST in the cloud …

The Study Of The Mouse Schlafen Family Members As Mediators Of Antiviral Activity, Julia Fernanda Hernandez

Open Access Theses & Dissertations

The Schlafen family of proteins was first characterized in 1988, and since then evidence of their relevance in different physiological and pathological situations have been accumulating although at a slow pace. Hence, the biological roles of these proteins remain ill-defined. The expression of these proteins is positively regulated by type 1 interferons, constituting a component of the innate immune response. Functions of these proteins vary from regulation of cell proliferation to restriction of viral infections. Recent studies have implicated SLFN11 and SLFN13 as inhibitors of HIV-1 infection2-4. The mechanism of action of SLFN11 resides in its capacity to regulate the …

Impact Of Cryptococcus Neoformans Polysaccharide Capsule On Astrocytes, Yeon Hwa Woo

Open Access Theses & Dissertations

Cryptococcus neoformans is a neurotropic, opportunistic, encapsulated, yeast-like fungus that causes life-threatening meningoencephalitis in both healthy and immunocompromised individuals. C. neoformans infects 1,000,000 people and causes 210,000 deaths worldwide annually, mostly in sub-Saharan Africa. The polysaccharide capsule of C. neoformans is the fungus major virulent factor. Glucuronoxylomannan (GXM), the main component of the capsule is abundantly released into brain tissue during C. neoformans infection, causing immunosuppressive defects in the host. C. neoformans is inhaled from the environment, disseminate via bloodstream, and crosses the blood brain barrier (BBB) to cause cryptococcal meningoencephalitis (CM). Although CM causes significant mortality in HIV/AIDS patients, …

A Cellulose-Based Biological Sensor For The Quantitative Determination Of Glucose And Glycated Hemoglobin (Hba1c), Gilberto Henao-Pabon

Open Access Theses & Dissertations

ABSTRACT

Importance: Diabetes is a common world-wide disease characterized by insulin resistance and as result there is an increased risk of cardiovascular disease and other metabolic abnormalities, that contribute to irreversible end-organ damage. The cause of diabetes is multifactorial and includes genetic, inflammatory and environmental factors plus lifestyle issues. Because in diabetes there are high levels of glucose and glycated hemoglobin, these molecules are used in clinical settings for the acute and chronic management of diabetic patients.

Objectives: a. To design and build an electrochemical biological sensor using the enzyme Glucose Oxidase (GOX) to detect glucose in biological fluids.

b. …

The Drones' Impact On Precision Agriculture, Ibrahim Naji

Open Access Theses & Dissertations

A study to assess the overall impact of drones in the agricultural sector. The specific goal of this research was to provide a drone system to ward off pestering birds from crops to allow for better growth and an increased yield. Along with providing a user-friendly coded drone system for farmers that is cost effective, this project has inspired other areas of use for the drone.

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 …

Magnetotelluric Analysis Of Central Kenya Kenyan Rift Volcanoes For Geothermal Development, Anna Wairimu Mwangi

Open Access Theses & Dissertations

Abstract

High temperature geothermal resources are vast along rift margins because of emplacement of magma in shallow crust. This is the case along the Kenyan Rift valley also known as the Gregory Rift. It is the Eastern arm of the East African rift and a chain of volcanoes along the rift graben characterizes it. We use (MT) magnetotelluric method to image beneath the peralkaline province of the Kenya Rift i.e. Olkaria, Eburru, Badlands, and Longonot volcanoes. The resistivity structure shows active geothermal activity happening at the upper 3km from the subsurface as evidenced by low resistivity cap rock comprised of …

Safety Airway For Small Unmanned Aerial Vehicles Using A Gas Particles Behavior Analogy, Pablo Rangel

Open Access Theses & Dissertations

The United States Federal Aviation Administration (FAA) implemented the Part 107 legislation to allow the flight of Unmanned Aerial Vehicles (UAV) for commercial use (i.e. package deliveries, power transmission line inspections, etc.) in the National Airspace System (NAS). As a consequence of the newly introduced rules, there is an increased risk for accidents involving injured bystanders or damaged to property. The work within this document defines a UAV to UAV safety distance model that acts as a range sensor enabled "elastic bubble". The length of the UAV safety bubble contracts and expands upon changing airway wind speed conditions. It also …

Optimization Of Collagen Microneedle Using Taguchi Method, Abhilash Aditya

Open Access Theses & Dissertations

Research is conducted to create dissolving collagen microneedles and to optimize the parameters for close to perfect dimension microneedles. A collagen microneedle patch has been developed with a micro-manufacturing process (micro-molding process). The collagen microneedles, varying in length from 300 to 600-μm may reach different targeted layers of the skin depending on the application. As the microneedles penetrate the skin they dissolve, delivering collagen through the epidermis. Such addition of collagen directly to the dermis layers allows it to be absorbed, increasing skin's strength and resilience, since it is one of the natural components of the younger looking skin. This …

Using Zeolite For Soil Moisture Retention And Salinity Control, Mark Torres

Open Access Theses & Dissertations

There is a great need in the desert southwest United States for exploring ways to save water in agriculture as it accounts for up to 90 percent of water consumption in many western states (USDA 2016). As surface water reaches critical lows the dependence on ground water has increased leading to the need for deeper wells with higher salt concentrations. The studies conducted for this research included using zeolites from the St Cloud Mining Company in Winston, New Mexico to determine the feasibility of using these zeolites to help and retain moisture in zeolite treated soils. The Volumetric Water Content …

Design Optimization And Optical Characterization Of A High Temperature Solar Receiver, Samia Afrin

Open Access Theses & Dissertations

Concentrated solar power (CSP) is a fast forwarding technology in power generation sector because of its' competitive price, abundance in nature and the most important fact is its' energy storage capability. Among the four types of available CSP technology, central receiver has more potential concerning with high temperature, power block efficiency and levelized cost of energy (LCOE). Other than conventional type of receiver design, the concept of this work is very particular in a sense of its design novelty.

National Renewable Energy Laboratory (NREL) come up with a new concept of high temperature solar receiver called near black body (NBB) …

Alkali Promoted Molybdenum (Iv) Sulfide Based Catalysts, Development And Characterization For Alcohol Synthesis From Carbon Monoxide And Hydrogen, Belinda Delilah Molina

Open Access Theses & Dissertations

For more than a century transition metal sulfides (TMS) have been the anchor of hydro-processing fuels and upgrading bitumen and coal in refineries worldwide. As oil supplies dwindle and environmental laws become more stringent, there is a greater need for cleaner alternative fuels and/or synthetic fuels. The depletion of oil reserves and a rapidly increasing energy demand worldwide, together with the interest to reduce dependence on foreign oil makes alcohol production for fuels and chemicals via the Fischer Tropsch synthesis (FTS) very attractive. The original Fischer-Tropsch (FT) reaction is the heart of all gas-to-liquid technologies; it creates higher alcohols and …

Gas-Solid Bed Hydrodynamics Of Non-Spherical Particles, A S M Raufur Rahim Chowdhury

Open Access Theses & Dissertations

Gas-solid beds are ubiquitous in industrial and energy production applications. Examples include fluidized beds, which are used in many systems such as in Integrated Gasification Combined Cycle (IGCC) power plants or in chemical looping systems. These examples and others involve complicated interactions between each phase of reactants in the system. The motivation of this work stems from the need for a better understanding of bed hydrodynamics in existing energy systems; results from this work can be used directly in software such as Fluent to more accurately predict flow behaviors of gas and solid phases. The experimental data are collected from …

Development Of A Variable Stiffness Locally Adjustable And Repairable Low-Cost Energy Storage And Return Carbon Fiber Prosthetic Foot: A Feasibility Study, Joshua Scott Bowen

Open Access Theses & Dissertations

Background: Energy storage and return (ESAR) prosthetic feet were developed to improve the mobility and function of lower-limb amputees. Amputees in the Developing World amputees lack this technology. Most current Developing World prosthetic solutions do not adequately address the needs of active amputees and were not designed to pass international standard tests. Developing a low-cost, repairable, adjustable, energy storage and return prosthetic foot would close this technological gap and improve the mobility and function of active amputees. The goal of this research is to determine the feasibility of fabricating a low-cost, adjustable, ESAR, repairable prosthetic foot manufactured from carbon fiber …

Transatlantic Maritime Transportation Between The Czech Republic And The United States, Petr Toman

Open Access Theses & Dissertations

Maritime transportation is the backbone of today´s world trade and therefore there special attention should be paid to all subjects concerning this mode of transportation. It is also necessary to complement maritime transportation by other modes, such as rail and/or truck (road). This thesis deals with the problems of maritime transportation and provides the summary of recent developments, trends and statistics mainly on Transatlantic maritime routes (Europe to U.S.). Besides maritime transportation, this thesis also reviews the trends and statistics of rail and truck (road) transportation in U.S. and Europe.

The second part of thesis seeks to create a mathematical …

Synthetic Asphaltene As A Novel Dye In Dye Sensitized Solar Cells Dsscs, Hassan Sharif

Open Access Theses & Dissertations

This dissertation approves the possibility of the first time use of synthetic asphaltene as new dye in dye sensitized solar cells. In which the conversion efficiency of synthetic asphaltene DSSC has improved up to 2.0 %. Synthetic asphaltene sample was prepared from the starting material as in literature and applied for various solar cell parameters of TiO2 based dyesensitized solar cell DSSC. DSSCs were fabricated using the synthetic asphaltene as dye. Different variables and parameters were carried out to test the photovoltaic performance of the cells, these parameters include open-circuit voltage, short-circuit current; fill factor. The first result was obtained …

Recovering Magnesium Hydroxide And Sodium Chloride From Zero Discharge Desalination Concentrate Streams, Alemayehu Asfaw Yetayew

Open Access Theses & Dissertations

UTEP and Veolia Water Solutions & Technologies have been demonstrating and commercializing the Zero Discharge Desalination (ZDD) technology as part of a three year project sponsored by the U.S. Bureau of Reclamation. ZDD is able to achieve up to 98% recovery by desalinating brackish groundwater. ZDD is typically comprised of a reverse osmosis (RO) or nanofiltration (NF) system and a unique variation of electrodialysis called electrodialysis metathesis (EDM). The ZDD technology increases the yield of fresh water from water supplies that contain enough CaSO4 to cause precipitation problems when the water is treated with RO or NF alone. The EDM …

Development Of A New Genetic Algorithm To Solve The Feedstock Scheduling Problem In An Anaerobic Digester, Ana Cram

Open Access Theses & Dissertations

Genetic Algorithm

Scheduling

Anaerobic digester