Engineering Commons^™

Optimization Of Uv-Led Curable Printing Material For Applications In Direct Writing Systems: Inkjet, Reverse Offset, And Micro Dispensing Gpd, Ada Judith Ortega Varela

Open Access Theses & Dissertations

The quality of a product fabricated by direct writing methods will depend greatly on the properties of the printing material and its compatibility with the printing process. Although multiple advances in developing printing inks and pastes with novel properties are being made, the potential those can bring to electronics is hindered by their stability and performance during the printing process. In this study a UV-LED curable acrylic material was used to test the optimization of inks and pastes for three of the most common direct writing systems: Piezo-type Inkjet, Reverse Offset Roll to Plate, and Micro Deposition. The viscosity of …

Hydrogen Generation From Ammonia Borane And Water Through The Combustion Reactions With Mechanically Alloyed Al/Mg Powder, Daniel Rodriguez

Open Access Theses & Dissertations

Finding and developing a safe and effective method for hydrogen storage is integral to its use as an alternative source of energy. The goal of the studies described in this Thesis was to investigate the feasibility of developing combustible hydrogen-generating compositions based on ammonia borane and novel energetic materials such as nanocomposite and mechanically alloyed reactive materials, recently obtained by Prof. Edward Dreizin's team at the New Jersey Institute of Technology (NJIT). Such compositions could be stored for long time and release hydrogen on demand, upon ignition. The first phase of the research included thermodynamic calculations for combustion of ammonia …

Master's In Electrical Engineering, Ricardo Xavier Rodriguez

Open Access Theses & Dissertations

This project is a focus on characterizing the process for actualizing three dimensional structures out of a carbon nanostructure composite via a direct print additive manufacturing process. Manufacturing parts additively enables for realization of geometrically complex shapes that often times cannot be manufactured any other way. The specificity of a material's properties have to be such, that the processing method can precisely place and bond material to itself in a highly repeatable manner. Commercial materials for additive manufacturing are have been optimized with these goals in mind and, therefore, often times lack the rigor and robustness for many applications.

The …

Effect Of Rhenium On Short Term Oxidation Of Niobium Based Alloys For High Temperature Applications, Ruth M. Sierra

Open Access Theses & Dissertations

The effect of adding Re to Nb-based alloys and is intended to analyze in depth the microstructures of Nb based alloys with Re, Si and Cr additions, in atomic percentages. The binary alloys (Nb-5Re, Nb-5Si and Nb-5Cr) reveal the formation of a single phase, NbSS, NbSS+ Nb3Si and NbSS+NbCr2 respectively. The formation of the single phase was confirmed by TEM studies for the Nb-5Re alloy. Addition of Re to form ternary alloys, has helped in the formation of Nb5Si3 and (Nb, Re) Cr2, in Nb-5Re- 5Si and Nb-5Re-5Cr respectively. Quaternary alloy Nb-5Re-5Si-5Cr has Nb5Si3, NbCr2 and NbSS. The oxidation behavior …

Modeling And Simulation Of A Lead-Free Active Structural Fiber For Multifunctional Composites, Linda Vera

Open Access Theses & Dissertations

Piezoelectric materials are widely used in a many areas of science and technology due to their unique electromechanical properties. The transformation of mechanical energy into electrical energy and vice versa caused by the piezoelectric effect has led to the development of piezoelectric sensor devices and actuators used in accelerometers, pressure and vibration meters, micropositioning devices, ultrasound generators, structural health monitoring, etc.

The most used piezoelectric material to this day is lead zirconate titanate PbZrO3-PbTiO3 (PZT) because of its high piezoelectric coefficient and Curie temperature, which allows it to be used in a more wide variety of applications. However, the commercial …

Design Optimization Of The Heat Transfer Model For A High Heat Flux Test Facility, Linda Hyemin Yoon

Open Access Theses & Dissertations

There are a variety of fuels that are utilized for space applications and in recent years, environmentally friendly fuels have been of interest. In the case of bipropellant rocket systems, hydrocarbon fuels have come to the attention of scientists and engineers. In particular, liquid methane was of interest in this study because of its physical and chemical advantages over other fuels, such as liquid hydrogen. Rocket engines rise to very high temperatures and to avoid catastrophic mechanical failure, a cooling system must be implemented within the engine to cool the walls. To get a better understanding of the fluid flow …

E-Quality Control Using 3d Reconstruction And 3d Measurement, Jun Zheng

Open Access Theses & Dissertations

Recently more and more industrial applications use image acquisition to improve product manufacturing. The observed growth in the last few years is mainly due to the great advances in acquisition devices which are now affordable for more industrialists. Moreover, the increasing demands in the quality requirements of the products are a great stimulus to apply vision tools which allow a better understanding of the impact of the manufacturing process on the product quality. Vision tools have been used in many industrial fields. But the traditional 2D vision is not as reliable as 3D measurement due to the limitations of the …

A Circuit-Based Algorithm For Two-Phase Flow At The Pore Scale In Porous Media, Todd Dorethy

Open Access Theses & Dissertations

Models of two-phase flow in porous media are of practical interest in many fields of science and engineering such as in oil recovery and hydrology. For this class of problem, an immiscible fluid is injected into a single-phase, porous medium to evict its valuable, native fluid. Because the aim is to amass as much of the indigenous fluid as possible, models attempt to output reliable flow regime patterns depicting how well the invading fluid displaces the native fluid.

Flow regime patterns generally depend upon the geometry of the domain, stimulation at the boundaries, and properties of the invading and native …

Characterization Of W-Ti-O Thin Films For Application In Photovoltaics, Amanda Patricia Christmas

Open Access Theses & Dissertations

Photovoltaic (PV) devices consist of the conversion of light energy into electricity. Nearly all PV technologies employ transparent conducting oxides (TCO) as an integral part of the de-vice structure so that the light can reach the semiconductor. The predominant transparent conducting oxide (TCO) that is currently being used in industry is indium tin oxide (ITO). However, Indium (In) is high in cost and becoming scarce in the world. This work is focused towards Titanium doped Tungsten oxide (WO3) for TCO application. The ultimate goal is making novel, cheaper, and efficient TCOs based on W-Ti-O films. Titanium will enhance the conductivity …

Geochemical Studies Of Backfill Aggregates, Lake Sediment Cores And The Hueco Bolson Aquifer, Anita Thapalia

Open Access Theses & Dissertations

This Dissertation comprises of three different researches that focuses on the application of geochemistry from aggregates, lake sediment cores and Hueco Bolson Aquifer. Each study is independent and presented in the publication format. The first chapter is already published and the second chapter is in revision phase. Overall, three studies measure the large scale (field) as well as bench scale (lab) water-rock interactions influenced by the climatic and anthropogenic factors spans from the field of environmental geology to civil engineering.

The first chapter of this Dissertation addresses the chemical evaluation of coarse aggregates from six different quarries in Texas. The …

Nanometric Structure-Property Relationship In Hafnium Oxide Thin Films Made By Sputter-Deposition, Mirella Vargas

Open Access Theses & Dissertations

Hafnium oxide (HfO2) is technologically an important material, which exhibits a unique set of properties such as a high dielectric constant (k~25) and wide band gap (~5.7 eV) which make this material attractive in the fields of microelectronics and optoelectronics. HfO2 has become the leading candidate to replace SiO2 dielectrics in gate oxides due to a higher permittivity and reportedly lower electron tunneling effects. HfO2 exhibits various polymorphs; the thermodynamic stability and phase existence depends on the temperature and pressure conditions. In addition, the controlled growth and manipulation of specific HfO2 crystal structures at the nanoscale dimensions is the driving …

An Intelligent System For High Resolution Radar Systems, Janette C. Briones

Open Access Theses & Dissertations

Cognitive radio is a recent, novel approach that integrates machine perception software into wireless systems. The term cognitive radio was first used by Joe Mitola. The concept and the term cognitive radio quickly caught the attention and interest of many in the communications field. Cognitive radios are capable of making decisions and selecting or modifying the operating parameters of a radio. Given these capabilities, it is feasible to build a cognitive radar system as introduced by Simon Haykin in 2006. Cognitive radar, as described by Haykin, is an intelligent system that must be aware of its environment, uses prior knowledge, …

Natural Selectivity Of Nickel And Vanadium In Crude Oil, Olienka P. De La O Fernandez

Open Access Theses & Dissertations

Nickel and Vanadium have always been found in crude oil all around the world. The metal content is found mainly in porphyrin structures in the asphaltene fraction of the petroleum. In order to determine the reason for this natural preference, a set of experiments testing thermodynamics, kinetics, and other factors were performed. Candidate metalloporphyrins containing Vanadyl, Chromium, Iron, Nickel, Copper and Zinc were analyzed through chemical reactions characterized using Silica Column Chromatography, HPLC, MS and UV-Visible. Theoretical analysis of the stability of metalloporphyrins was conducted using DFT/NRLMOL for computational calculation. The analysis of all factors leads us to conclude that …

An Explanatory And Comparative Analysis Of Freight Transportation In Eu And U.S. Highways, Luis Alberto Hernandez

Open Access Theses & Dissertations

This thesis provides resources for data collection regarding road freight transportation in the Unites States and the European Union, as well as an explanatory description of data available at each source. Afterwards, individual analysis of the current state of affairs of the highway freight transportation systems in U.S. and EU are performed. Thereafter, an explanatory and comparative analysis between the two land freight transportation systems is performed in terms of regulatory authorities and associations, trucks volume flow, freight weight and volume flow, major issues affecting the system, infrastructure funding sources, and major logistics hubs. Besides, a correlation analysis was performed …

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 …

Growth And Analysis Of Micro And Nano Cdte Arrays For Solar Cell Applications, Brandon Adrian Aguirre

Open Access Theses & Dissertations

CdTe is an excellent material for infrared detectors and photovoltaic applications. The efficiency of CdTe/CdS solar cells has increased very rapidly in the last 3 years to ~20% but is still below the maximum theoretical value of 30%. Although the short-circuit current density is close to its maximum of 30 mA/cm2, the open circuit voltage has potential to be increased further to over 1 Volt. The main limitation that prevents further increase in the open-circuit voltage and therefore efficiency is the high defect density in the CdTe absorber layer. Reducing the defect density will increase the open-circuit voltage above 1 …

Multi-Objective Border Patrolling Optimization Using Game Theory And Evolutionary Algorithms, Franciso Oswaldo Aguirre

Open Access Theses & Dissertations

Border security has evolved significantly since the days when no more than 75 Mounted Guards patrolled the U.S. border in the early 1900's. The border region includes thousands of miles of both land and maritime borders that must be controlled, as well as commercial transportation networks. One of the primary components of the Department of Homeland Security (DHS) is the U.S. Customs and Border Protection (CBP) agency. One of the most typical activities performed by CBP is patrolling the expansive open areas in between official points of entry (POEs) to prohibit illegal entry attempts. Roving patrols are routinely conducted by …

Combustion Synthesis Of Molybdenum Silicides And Borosilicides For Ultrahigh-Temperature Structural Applications, Mohammad Shafiul Alam

Open Access Theses & Dissertations

Molybdenum silicides and borosilicides are promising structural materials for gas-turbine power plants. A major challenge, however, is to simultaneously achieve high oxidation resistance and acceptable mechanical properties at high temperatures. For example, molybdenum disilicide (MoSi₂) has excellent oxidation resistance and poor mechanical properties, while Mo-rich silicides such as Mo₅Si₃ (called T₁) have much better mechanical properties but poor oxidation resistance. One approach is based on the fabrication of MoSi₂−T₁ composites that combine high oxidation resistance of MoSi₂ and good mechanical properties of T₁. Another approach involves the …

Examining The Role Of Attention In Steering Using A Dual Task Paradigm, Venkata Naga Pradeep Ambati

Open Access Theses & Dissertations

Changing the direction of locomotion, often referred to as "steering", is an integral component of human locomotion. Steering requires maintaining dynamic balance while translating and rotating the body in the new travel direction. Given the level of sensation thought to be involved in sub serving goal directed modifications in steering, it is highly likely that steering control may require attention. Since attention resources decline with increasing age, we may see the influence of age on steering performance when attention resources are limited. Therefore, this study sought to investigate the role of attention in steering using a dual task paradigm in …

Simulation Of Heat And Mass Transfer In Suns River Solar Distillation, Houman Azari

Open Access Theses & Dissertations

Many regions around the world have limited fresh water resources, and we need to desalinate brackish water resources for drinking and irrigation purposes. Most of the world is also facing energy challenges which encourages engineers and scientists to use renewable energy resources instead of hydrocarbon fuels. Arid regions such as the Middle East, many African countries, and the southwestern United States typically have abundant solar irradiance and brackish or saline water supplies. Solar-thermal desalination could be an important supply of fresh water in these regions.

The classic solar still is not efficient for providing large amounts of clean water for …

Cell Releasing System Using Light Responsive Photovoltaic Devices, Mohammod Khairul Kabir Bhuyan

Open Access Theses & Dissertations

Tissue and organ regeneration via transplantation of cell bodies in-situ has become an emerging strategy in regenerative medicine. Injected or implanted cells must be available in large enough numbers and suitable delivery methods must be found especially when implantation into the affected tissue is not possible. In addition, better understanding of how to mitigate the inflammatory reactions and how to degrade the cell carriers are needed. Current cell-based therapies are limited to injection or implantation of cell suspensions or implantation of cell sheets. Development of alternative systems to obtain cell sheets or other functional cellular structures are required. We are …

Numerical Investigation Of Impact Of Relative Humidity On Droplet Accumulation And Film Cooling, Luz Irene Bugarin

Open Access Theses & Dissertations

During the summer, high inlet temperatures affect the power output of gas turbine systems. Evaporative coolers have gained popularity as an inlet cooling method for these systems. Wet compression has been one of the common evaporative cooling methods implemented to increase power output of gas turbine systems due to its simple installation and low cost. This process involves injection of water droplets into the continuous phase of compressor to reduce the temperature of the flow entering the compressor and in turn increase the power output of the whole gas turbine system. This study focused on a single stage rotor-stator compressor …

Design And Development Of A High Velocity Oxy-Fuel Thermal Spray Gun, Luisa Alejandra Cabrera Maynez

Open Access Theses & Dissertations

The High Velocity Oxy-Fuel (HVOF) system is a highly promising technique for the production of thermal barrier coatings (TBCs), helpful in the protection of materials exposed to extreme thermal and corrosive environments. Coatings generated through the technique are employed in industrial settings to extend product life, increase performance and decrease maintenance costs. HVOF yields lower porosity and higher adhesion TBCs when compared to similar thermal spraying processes. Though gas fuelled systems are the norm in this technique, there is a recent interest in employing liquids due to their low cost and increased deposit density. Economic and highly scalable, HVOF process …

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 …

Integrated Sustainability Decision-Making Framework, Michael Paul Cole

Open Access Theses & Dissertations

The Integrated Sustainability Decision-Making Framework (ISDMF) is an 'ideal case' framework developed at the University of Texas El Paso (UTEP) from 2012 to present to provide the most comprehensive and concise sustainability strategy and decision-making template available.

Sustainable decision-making improves community Quality of Life, but is often beyond the reach of the majority. A framework that is most approachable, actionable, and adoptable can accelerate convergence on and continued operation of a sustainable solution. Research confirms that published frameworks continuously emerge, and are infinite in number. Iterations benefit from prior work, and contribution occurs when an 'ideal case' is envisioned, best …

Optimized Integrated Software Package For Classification Of Small Airway Dysfunction Using Genetic Algorithms, Elias Estrada

Open Access Theses & Dissertations

Due to the similarity in the symptoms of respiratory disorders, an accurate diagnosis could be a difficult task. Regarding asthma as the main focus of this research, early detection of small airway impairment could represent a better opportunity for timely diagnosis. An integrated software package (ISP) based on the impulse oscillometry technique, has been developed to serve as an important tool for clinicians during classification of asthma severities on children [1]. The current version of the ISP was tested with data obtained during several years by Dr. Homer Nazeran and Dr. Michael Goldman from 110 Hispanic children [2], providing an …

Situational Assessment Of Multi Sensor Data, Eduardo Estrada

Open Access Theses & Dissertations

The importance of sensors has grown dramatically through the years, specially since they have the capability to create a specific task. Multiple sensor fusion is an area that has rapidly grown due to its multiple and beneficial applications. It is common to develop devices that have multiple sensors; however, the fusion of these multiple sensors to make a single output is remarkable. In fact, this is the way people chose to try to model the human body which has innumerable sensors and makes one decision. The development of sensor fusion not only helps create innovations in technology, but has the …

An Experimental Investigation On Liquid Methane Heat Transfer Enhancement Through The Use Of Longitudinal Fins In Cooling Channels, Manuel De Jesus Galvan

Open Access Theses & Dissertations

In the past years, hydrocarbon fuels have been the focus of attention as the interest in developing reusable, high-performing liquid rocket engines has grown. Liquid methane (LCH4) has been of particular interest because of the cost, handling, and storage advantages that it presents when compared to currently used propellants. Deep space exploration requires thrusters that can operate reliably during long-duration missions. One of the challenges in the development of a reliable engine has been providing adequate combustion chamber cooling to prevent engine failure. Regenerative (regen) cooling has presented itself as an appealing option because it provides improved cooling and engine …

3d Printed Spatially Variant Metamaterials, Cesar Roman Garcia

Open Access Theses & Dissertations

The recent advancement in 3D printing has created a new way to design electronics and electromagnetic devices. This allows for a new breed of non-planar designs to be used, fully exploiting all three dimensions like never before. More functions can be fit into the same amount of space, products with novel form factors can be more easily manufactured, interconnects can be routed more smoothly, interfaces can be better implemented, electrical and mechanical functions can be comingled, and entirely new device paradigms will be invented. When departing from traditional planar topologies many new problems arise like signal integrity, crosstalk, noise, and …

Gadolinia Doped Hafnia (Gd2o3- Hfo2) Thermal Barrier Coatings For Gas Turbine Applications, Satya Kiran Gullapalli

Open Access Theses & Dissertations

Thermal efficiency of the gas turbines is influenced by the operating temperature of the hot gas path components. The material used for the hot gas path components can only withstand temperature up to a certain limit. Thermal barrier coatings (TBC) provide the additional thermal protection for these components and help the gas turbine achieve higher firing temperatures. Traditionally available yttria stabilized zirconia (YSZ) TBCs have a limitation up to 1200 C due to their phase transformation. The present work focuses on gadolinia based hafnia (GSH) TBCs to study their potential to replace the YSZ coatings. Different compositions of gadolinia doped …