Engineering Commons^™

Organic Photovoltaics: A Charge Transfer Perspective In The Study Of Donor-Acceptor Pairs, 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 CT energies in excellent agreement with benchmark experimental data. With an accurate excited state method …

Development Of The Control And Ignition Systems On A High Pressure Gas Turbine Combustor, Carlos Alejandro Valdez

Open Access Theses & Dissertations

The ignition and control systems of a laboratory scale high-pressure gas turbine combustor were developed in the present work. This work provides a detailed description of the design, development and testing of the remote control system developed for a High Pressure Gas Turbine Combustor (HPTC).

The combustor has the capability to operate at pressures up to 1.5 MPa and temperatures up to 2400 K. It is also designed for a maximum air and fuel flow rates of 81.93 g/s and 35.77 g/s respectively. The fuel used will be CH4 for the early experiments but it is designed to operate using …

Numerical Analysis Of Single Tank Thermocline Thermal Storage System For Concentrated Solar Power Plant, Samia Afrin

Open Access Theses & Dissertations

The overall efficiency of a Concentrating Solar Power (CSP) plant depends on the effectiveness of Thermal Energy Storage (TES) system. A Single tank TES system has potential to provide effective solution. In a single tank TES system, a thermocline region, which produces the temperature gradient between hot and cold storage fluid by density difference, is used. Preservation of this thermocline region in the tank during charging and discharging cycles depends on the uniformity of the velocity profile at any horizontal plane. One of the major challenges for the single tank thermocline is actually maintaining the thermocline region in the tank, …

The Application Of Fuzzy Granular Computing For The Analysis Of Human Dynamic Behavior In 3d Space, Murad Mohammad Alaqtash

Open Access Theses & Dissertations

Human dynamic behavior in space is very complex in that it involves many physical, perceptual and motor aspects. It is tied together at a sensory level by linkages between vestibular, visual and somatosensory information that develop through experience of inertial and gravitational reaction forces. Coordinated movement emerges from the interplay among descending output from the central nervous system, sensory input from the body and environment, muscle dynamics, and the emergent dynamics of the whole neuromusculoskeletal system.

There have been many attempts to directly capture the activities of the neuronal system in human locomotion without the ability to clarify how the …

Selection Of Sustainable Rigid Pavement Using The Mechanistic-Emperical Pavement Design Guide, Laith Ali Al Sabty

Open Access Theses & Dissertations

A new pavement design guide called "Mechanistic-Empirical Pavement Design Guide (ME-PDG)" has been developed for design and rehabilitation of pavements. The guide uses general characteristics, traffic, environmental conditions, and pavement structure information to estimate pavement life. ME-PDG is a comprehensive program which requires significant number of inputs and time to analyze and predict pavement performance.

In El Paso, Texas most of the urban highways are constructed as Continuously Reinforced Concrete Pavement (CRCP). Although commonly placed, the design life of CRCP pavements is rarely realized. In addition, the cost of constructing CRCP is significantly higher than the Jointed Plain Concrete Pavement …

Analysis Of Particulate Matter Air Quality Impacts On Sunland Park, New Mexico Due To Dust Emissions From Puerto Anapra, Mexico Using A Complex Terrain Air Dispersion Model Calpuff, Grisel Edith Arizpe

Open Access Theses & Dissertations

The City of Sunland Park is located in Doña Ana County in southern New Mexico. The City has unusual boundaries which border not only with other communities in New Mexico but also the State of Chihuahua, Mexico to the south and the City of El Paso, Texas to the east. This area is considered part of the Paso del Norte Airshed (PdNA), which is comprised also by El Paso County, Texas and Ciudad (Cd.) Juarez, Mexico. Historically, this region has had air quality problems and compliance issues with National Ambient Air Quality Standards (NAAQS), including particulate matter and ozone pollution. …

Instrumentation, Control And Torch Ignition Systems Development For Lox/Methane Propulsion Research, Jesus Betancourt-Roque

Open Access Theses & Dissertations

A liquid propulsion research facility has been developed at the Center for Space Exploration Technology Research at The University of Texas at El Paso. This facility has capabilities for producing up to 25 liters of Liquid Methane, feeding LOX/Methane propellants to 100 N class thrusters and conducting automated steady state and pulsing combustion experiments. This work describes the design, development and testing process of the Data Acquisition and Remote Control System developed to integrate an Altitude Simulation System, a Cryogenic Delivery System, and multiple rocket combustors and thrusters. A Torch Ignition System development is detailed as well as the evaluation …

Methodologies For The Analysis Of Checked Baggage Inspection Systems, Nela Blejcharova

Open Access Theses & Dissertations

To enhance the security of the aviation system it is necessary to have a Checked Baggage Inspection System (CBIS) that is effective (that is, the highest possible detection probability or minimum false clear probability) yet efficient (that is, minimize the false alarm probability that causes inconvenience to passengers).

The first objective of this thesis is to review passenger, carry-on and checked baggage inspection procedures at airports

The second objective of this thesis is to develop a methodology using the optimization approach to set the optimal values of the sensitivity of the screening devices to minimize the total cost of inspecting …

Video Mosaicing Using Inertial Sensors, Arturo Maya Pereyra

Open Access Theses & Dissertations

A method to reduce the process complexity of Video Mosaicing could rely on information concerning the orientation of the camera instead of image feature tracking. Inertial sensors (e.g. accelerometers and gyros) could form part of a low cost motion based technology which can be used in this case and this thesis details an approach for Video Mosaicing based on such technology that requires non-computationally intensive algorithms.

Measurement And Analysis Of Turbulent Syngas/Air And Methane Oxy-Combustion, Vishwanath Reddy Ardha

Open Access Theses & Dissertations

Development of a next generation gas turbine combustors for power production by using fossil fuels is increasing substantially in order to maintain energy sustainability. National Energy Technology Laboratory has made efforts for developing hydrogen and oxy-fuel based gas turbine combustors which could enhance plant efficiency and ensure low or zero NOx production without sacrificing operational advantages. The current experimental work aims to characterize the turbulent flow-field of premixed syngas/air flames, methane/oxy flames and syngas/oxy flames in a laboratory scaled burner by varying the Reynolds numbers, blockage ratios, firing inputs and blockage ratios in the upstream of the burner. The effects …

Transparent And Amorphous W-Ti-O Nano-Coatings, Gaurav Baghmar

Open Access Theses & Dissertations

The present work was performed on the Ti-doping effects in a small and controlled amount into WO3 to produce W0.80Ti0.20O3. The aim of study is to explore the effect of Titanium (Ti) coupled with growth temperature on the growth of behavior, microstructure and optical properties. W0.80Ti0.20O3 coatings were fabricated using RF magnetron sputter-deposition onto Silicon (Si-100) wafers and optical quality Quartz substrates. The depositions were made in a wide temperature ranging from room temperature (25 ˚C) to 500 ˚C. X-ray diffraction (XRD), high-resolution scanning electron microscopy (SEM), Optical spectrophotometery and Spectroscopic Ellipsometry (SE) were performed to study the effect of …

Ozone Studies In The Paso Del Norte Region, Fernando Becerra-Davila

Open Access Theses & Dissertations

The Paso del Norte region forms the largest contiguous bi-national conglomerate on the US-Mexico border. With a combined population of around 2 million inhabitants, the Paso del Norte region is isolated, more than 500 km away from the nearest urban area of comparable size, thus making it an ideal location for air quality studies of an isolated urban environment.

The meteorological conditions leading to a high ozone episode in this region, such as the historical ozone episode of June 2006, are analyzed. It is well known that stagnation and minimal winds, high temperatures, and pressure ridges over the region are …

Comparison Study Between Fem And Sem For Wave Propagation Models Applied To Solids, Shaddy Roberto Castillo Ponton

Open Access Theses & Dissertations

Wave propagation is a field whose application has spread across many disciplines. In the field of structural engineering, wave propagation methods have focused their attention specifically in the area of structural health monitoring and active control of vibrations and noise. Likewise, the development of new methods and their application have been successful in the area of material science with a special emphasis on the field of structural integrity evaluation of anisotropic and inhomogeneous structures (laminated composite structures). The current available analysis tools are inadequate to handle the modeling of complex structures. One-dimensional wave propagation problems in solids are still a …

Raman And Infrared Study Of Electrospun Plla/Pcl Nanofiber Blends For Use In Tissue Engineering, Jose Luis Enriquez Carrejo

Open Access Theses & Dissertations

Recently, the biomedical engineering field has developed at a very fast pace as improved techniques and materials become available to promote its growth. Consequently, the research in polymeric biomaterials has been highly stimulated by this trend. The goal of the current research is to demonstrate the usefulness of the Raman scattering, Raman mapping, and infrared absorption spectroscopies to tissue engineering, by spectroscopically characterizing blends of PLLA and PCL polymers, which were prepared by electrospinning with and without cell addition. The proposed use of these blends is as primary biomaterials in biodegradable scaffolds used in tissue engineering. Both Raman and infrared …

Development Of A Multi-Material, Multi-Technology Fdm System For Process Improvement Experimentation, David Espalin

Open Access Theses & Dissertations

Over the last three decades, developments within the area of Additive Manufacturing (AM) have resulted in novel technologies capable of producing highly customized, complex part geometries in a fraction of the lead time required by traditional manufacturing methods (e.g., injection molding, metal casting). In particular, fused deposition modeling (FDM), a material extrusion AM process, can produce parts using production-grade thermoplastics like acrylonitrile butadiene styrene, polycarbonate, and polyetherimide. Additionally, non-commercial materials (e.g., polycaprolactone, ceramic loaded polymers, carbon nanotube loaded polymers) have been processed using FDM in part to demonstrate the potential diversity in material selection.

Recently, a myriad of personal 3D …

Optimal Placement Of Wind Turbines On Non-Flat Terrain Using Cluster Identification And Multi-Objective Genetic Algorithm, Carlos Alejandro Garcia Rosales

Open Access Theses & Dissertations

To date, wind power has become very popular to produce electricity due to climate change, greenhouse gases and the fossil fuels crisis. Although using wind turbine technology to produce electricity is very mature, industries are looking to achieve the best utilization of the wind energy in order to fulfill the electrical needs for cities at a very affordable cost. In this thesis, a method entitled Cluster Identification Algorithm (CIA) and an optimization approach called a Multi-Objective Genetic Algorithm (MOGA) are integrated and implemented to maximize wind power efficiency and wind power in wind farms and minimize cost caused by the …

Sensor-Based Robotic Learning System For The Rehabilitation Of Arm, Chethan Ramachandra Keladi

Open Access Theses & Dissertations

In recent studies, the neurological studies has shown that the neurological disorders like Stroke, Parkinson's disease, Dystonia, Spinal Cord Injury (SCI), Cerebral Palsy (CP), etc., cause the disability of upper limb and one of the major issues with the neurological injuries is motor impairment. This issue is caused by the lack of interaction between the central nervous system (CNS) and muscles [1] and can be cured by the intensive training which includes repetitive and reaching tasks. The intensive training can be performed using conventional therapy and robot-assisted therapy, but the research has shown additional effects on motor recovery and functional …

Thin Film Growths Of Znte And Cdte On Various Substrates Using A Novel Close Space Sublimation Reactor Css4, Damian Marrufo

Open Access Theses & Dissertations

Thin films of CdTe have been grown on CdS in a variety of methods for use in thin film photovoltaic systems. Limits to the efficiency of CdTe/CdS solar cells have been attributed to defects in the lattice that occur between the interface of CdS and CdTe due to a lattice mismatch. A close space sublimation (CSS) reactor known as the CSS4 was designed and fabricated in UTEP to deposit complex layers of CdTe and ZnTe on top of a CdS film that is grown via chemical bath deposition in order to obtain a CdTe photovoltaic. Unfortunately, the original design and …

Alternatives To Piloting In Bracksih Waters: Accuracy And Precision Of Commerical Reverse Osmosis Membrane Design Model Projections, Erika Mancha

Open Access Theses & Dissertations

In a time of economic recession and drought, the Texas Water Development Board is reviewing alternatives to the current Texas Commission on Environmental Quality requirement of demonstration-scale pilot testing membrane desalination to decrease permitting costs and project construction delays. One alternative is to use engineering judgment with membrane manufacturer's software models to predict membrane performance and ensure that product water quality requirements will be met. To comply with state permitting requirements, the first few months of successful full-scale operation can be submitted in lieu of pilot demonstration.

The goal of this research is to characterize the accuracy and precision of …

Development Of Models To Estimate Modulus And Permanent Deformation Of Texas Bases, Eric Navarro

Open Access Theses & Dissertations

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The Effect Of Al, Mo, And B On The Oxidation Behavior Of Three Nb-Based Alloys, Victoria Rae Rangel

Open Access Theses & Dissertations

Extensive work has been undertaken to develop niobium based structural alloys for high temperature applications. These developments have led to the increase in engine operating temperatures and better performance efficiency. New materials including alloys based on metals with higher melting points such as molybdenum and niobium with silicon are now being examined as a better alternative to nickel base superalloys. Materials with a niobium silicide based composites have the potential for higher temperature capabilities. The oxidation behavior of Nb-20Cr-10Si and Nb-20Cr-10Si-5Al has been studied in a range of temperature from 700 to 1400°C in static air. Isothermal oxidation experiments indicate …

Structure Morphology And Optical Properties Of Nanocrystalline Ga2o3 Thin Films, Sampath Kumar Samala

Open Access Theses & Dissertations

Gallium Oxide thin films were produced by sputter deposition by varying the substrate temperature (T_s) in a wide range (T_s=25-800 oC) and under variable deposition time. The structural characteristics and optical properties of Ga₂O₃ films were evaluated using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDS), Rutherford backscattering spectrometry (RBS) and spectrophotometric measurements. The effect of growth temperature is significant on the chemistry, crystal structure and morphology of Ga₂O₃ films. XRD and SEM analyses indicate that the Ga₂O₃ films grown at lower temperatures were …

Graphene Stuctures For Energy Storage Application, Mohammad Arif Ishtiaque Shuvo

Open Access Theses & Dissertations

Energy storage devices are receiving extensive attention in recent years due to the increasing demand of energy. Super-capacitor is one of the energy storage devices with high specific power density and wide applications in electronic vehicles, commercial mobile electronics, and military devices. Carbon based materials are widely used in making Electrochemical Double Layer Capacitor (EDLC) or super-capacitor for their excellent porous nature along with their electron transport capability. By increasing the specific surface area of the porous carbon materials, specific capacitance of the super-capacitor can be significantly improved. Graphene, a newly discovered material, has been incorporated in making super-capacitor electrodes …

Development Of An Electronic Vehicle Miles Travelled Toll Model, Marketa Vavrova

Open Access Theses & Dissertations

This thesis presents the reasons why the fuel tax is no longer a viable source of revenues and suggests new sources of funding. One possibility is to replace the fuel tax with a distance-based toll applied nationwide. Vehicle miles travelled (VMT) fee is compared to the fuel tax, and the relationship between road infrastructure spending and fuel taxation in the United States (U.S.) and the European Union (EU) is explored. Also the European approach to taxation and tolling is described and compared to the situation in Texas.

The development of a statewide distance-based toll model to estimate the feasibility of …

A Study Of International Wastewater Challenges And Policy In The Tijuana River Watershed, Gloria Ann Villaverde

Open Access Theses & Dissertations

Since the 1930s, untreated and undertreated sewage from Tijuana, Baja California, México has been released into the Tijuana River Watershed causing contamination of the water supply, crops, the Tijuana Estuary and California beaches. Passage of the North American Free Trade Agreement (NAFTA) has exacerbated the problem by causing population and industrial growth explosions for which there have been insufficient services to meet the needs of the people. The waters of the Tijuana River flow (from México) north over the International Border, into the Tijuana Estuary, discharge out to the Pacific Ocean and often flow north, up the California Coast; therefore, …

The Effects Of Uncommon Silicides On The Oxidation Of Alloys From The Nb-Cr-Si System, Daniel Brendan Voglewede

Open Access Theses & Dissertations

Niobium based alloys are being tapped as potential successors to current nickel base superalloys in high temperature applications. In the aerospace industry, high temperature materials are constantly being pushed to higher temperature regimes in order to improve engine efficiency however current superalloys cannot be pushed further due to melting temperature limitations. Niobium, being a refractory metal, can withstand much higher temperatures than nickel however its oxidation properties are woefully inadequate.

The purpose of this study is to ascertain whether increased silicon additions can improve niobium oxidation properties by: forming ternary silicides with better oxidation properties and by preventing the formation …

Designing Optimal Aviation Baggage Screening Strategies Using The Monkey Search Algorithm, Edgar Ivan Jimenez

Open Access Theses & Dissertations

This thesis addresses the aviation baggage screening design problem considering several baggage screening devices which may be used for system implementation, the devices have different false clear and false alarm rates, throughput and purchase costs. In the present research, a comprehensive cost function which not only includes the cost associated with purchase and operation of baggage security devices, but also includes the indirect costs associated with device errors is used. A new monkey search based evolutionary algorithm is presented to determine the best selection of baggage screening security devices in order to minimize the expected annual total cost. The final …

Combustion And Compaction Of Lunar Regolith/Magnesium Mixtures, Armando Delgado

Open Access Theses & Dissertations

Feasible techniques that require low energy consumption and reduced costs are of vital importance to enable humans to explore and occupy space. In-Situ Resource Utilization (ISRU) is the branch in the Human Exploration Technology that studies the production of consumables and materials using indigenous lunar and planetary resources. ISRU represents an enabling opportunity for establishing long lasting human exploration missions. Construction materials produced in-situ are of special interest because of the high payload they represent when launching them from Earth. The in-situ production of construction materials that requires low energy input would be advantageous due to the limited energy in …

Development Of Advanced Polymer Nanocomposite Capacitors, Miguel Mendoza

Open Access Theses & Dissertations

The current development of modern electronics has driven the need for new series of energy storage devices with higher energy density and faster charge/discharge rate. Batteries and capacitors are two of the most widely used energy storage devices. Compared with batteries, capacitors have higher power density and significant higher charge/discharge rate. Therefore, high energy density capacitors play a significant role in modern electronic devices, power applications, space flight technologies, hybrid electric vehicles, portable defibrillators, and pulse power applications. Dielectric film capacitors represent an exceptional alternative for developing high energy density capacitors due to their high dielectric constants, outstanding breakdown voltages, …

Bod5 And Cod Data Analysis From The Northwest And Robert R. Bustamante Wastewater Treatment, Juan Carlos Adame

Open Access Theses & Dissertations

The objectives of this thesis are to explore the use of basic Statistical Process Control in a Wastewater Treatment Plant with secondary treatment. Additionally, to describe statistical behavior and review normality of some reportable parameters, also to analyze mainly parameters like BOD5 (Biological Oxygen Demand), Electrical Conductivity, and COD (Chemical Oxygen Demand) with seasons of the year and days of the week, using data from the Northwest (NW) and Robert R. Bustamante (RRB) Wastewater Treatment Plants from El Paso Texas.

The scope of this analysis is to understand how Statistical Process Control can help to predict peak and valleys of …