Engineering Commons^™

Effective Permittivity Of Dense Random Particulate Plasmonic Composites, Satvik N. Wani, Ashok Sangani, Radhakrishna Sureshkumar

Biomedical and Chemical Engineering - All Scholarship

No abstract provided.

Target Localization And Tracking In Non-Coherent Multiple-Input Multiple-Output Radar Systems, Ruixin Niu, Rick S. Blum, Pramod K. Varshney, Andrew L. Drozd

Electrical Engineering and Computer Science - All Scholarship

For a non-coherent MIMO radar system, the maximum likelihood estimator (MLE) of the target location and velocity, as well as the corresponding CRLB matrix, is derived. MIMO radar’s potential in localization and tracking performance is demonstrated by adopting simple Gaussian pulse waveforms. Due to the short duration of the Gaussian pulses, a very high localization performance can be achieved, even when the matched filter ignores the Doppler effect by matching to zero Doppler shift. This leads to significantly reduced complexities for the matched filter and the MLE. Further, two interactive signal processing and tracking algorithms, based on the Kalman filter …

Performance Of Permutation Trellis Codes In Cognitive Radio Networks, Raghed El Bardan, Engin Masazade, Onur Ozdemir, Pramod Varshney

Electrical Engineering and Computer Science - All Scholarship

In this paper, we investigate the error correction performance of Permutation Trellis Codes (PTC) combined with M -ary Frequency Shift Keying (M -FSK) modulation in Cognitive Radio Networks (CRNs). Using this modulation technique, a secondary user (SU) can improve its data rate by increasing its transmission bandwidth while operating at low power and without creating destructive interference to the primary users (PUs). Given an active PU, we first derive the bit error rate (BER) of the PTC based M-FSK system for a given SU link. For different PTCs, we compare the analytical BER with the corresponding simulation results. For the …

A New Framework For Distributed Detection With Conditionally Dependent Observations, Hao Chen, Biao Chen, Pramod K. Varshney

Electrical Engineering and Computer Science - All Scholarship

Distributed detection with conditionally dependent observations is known to be a challenging problem in decentralized inference. This paper attempts to make progress on this problem by proposing a new framework for distributed detection that builds on a hierarchical conditional independence model. Through the introduction of a hidden variable that induces conditional independence among the sensor observations, the proposed model unifies distributed detection with dependent or independent observations. This new framework allows us to identify several classes of distributed detection problems with dependent observations whose optimal decision rules resemble the ones for the independent case. The new framework induces a decoupling …

Mediums: Visual Integrity Preserving Framework, Tongbo Luo, Xing Jin, Wenliang Du

Electrical Engineering and Computer Science - All Scholarship

The UI redressing attack and its variations have spread across several platforms, from web browsers to mobile systems. We study the fundamental problem underneath such attacks, and formulate a generic model called the containerthreat model. We believe that the attacks are caused by the system’s failure to preserve visual integrity. From this angle, we study the existing countermeasures and propose a generic approach, Mediums framework, to develop a Trusted DisplayBase (TDB) to address this type of problems. We use the side channel to convey the lost visual information to users. From the access control perspective, we use the dynamic binding …

Generating Tones With A Vibrato Effect, M. Nakagawa, Shun Takai

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Provided are a method, computer storage device, and tone control device for generating tones with a vibrato effect. A determination is made of a key depression interval comprising a difference of a current time of a current note from a previous time of a previous note. A performance mode is set to a single tone mode, in which only one note is generated, or a polyphonic mode, in which multiple notes are simultaneously generated, based on the determined key depression interval. The tone is generated to output the current note with a first modulation magnitude in response to determining that …

Inherent And Model-Form Uncertainty Analysis For Cfd Simulation Of Synthetic Jet Actuators, Daoru Frank Han, Serhat Hosder

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A mixed (aleatory and epistemic) uncertainty quantification (UQ) method was applied to computational uid dynamics (CFD) modeling of a synthetic jet actuator. A test case, (ow over a hump model with synthetic jet actuator control) from the CFDVAL2004 work-shop was selected to apply the Second-Order Probability framework implemented with a stochastic response surface obtained from Quadrature-Based Non-Intrusive Polynomial Chaos (NIPC). Three uncertainty sources were considered: (1) epistemic (model-form) uncertainty in turbulence model, (2) aleatory (inherent) uncertainty in free stream veloc-ity and (3) aleatory uncertainty in actuation frequency. Uncertainties in both long-time averaged and phase averaged quantities were quantified using a …

Limited Thermal Conductance Of Metal-Carbon Interfaces, Jaime J. Gengler, Sergei V. Shenogin, John E. Bultman, Ajit K. Roy, Andrey A. Voevodin, Christopher Muratore

Chemical and Materials Engineering Faculty Publications

The thermal conductance for a series of metal-graphite interfaces has been experimentally measured with time-domain thermoreflectance (TDTR). For metals with Debye temperatures up to ∼400 K, a linear relationship exists with the thermal conductance values. For metals with Debye temperatures in excess of ∼400 K, the measured metal-graphite thermal conductance values remain constant near 60 MW m−2 K−1. Titanium showed slightly higher conductance than aluminum, despite the closeness of atomic mass and Debye temperature for the two metals. Surface analysis was used to identify the presence of titaniumcarbide at the interface in contrast to the aluminum and gold-carbon interfaces (with …

Design Mixers To Minimize Effects Of Erosion And Corrosion Erosion, Julian B. Fasano, Eric E. Janz, Kevin J. Myers

Chemical and Materials Engineering Faculty Publications

A thorough review of the major parameters that affect solid-liquid slurry wear on impellers and techniques for minimizing wear is presented. These major parameters include (i) chemical environment, (ii) hardness of solids, (iii) density of solids, (iv) percent solids, (v) shape of solids, (vi) fluid regime (turbulent, transitional, or laminar), (vii) hardness of the mixer's wetted parts, (viii) hydraulic efficiency of the impeller (kinetic energy dissipation rates near the impeller blades), (ix) impact velocity, and (x) impact frequency. Techniques for minimizing the wear on impellers cover the choice of impeller, size and speed of the impeller, alloy selection, and surface …

The Design And Development Of A Substitution Device For The Visually Impaired., Kieran John O'Callaghan

Theses

Current sensory substitution systems for the visually impaired are limited in terms of their spatial and depth resolution capabilities. They are unable to relay real-time 3D spatial information regarding objects in the direct path of the user. Recent advances in 3D imaging technology have presented new opportunities to develop improved sensory substitution systems to compensate for visual sensory loss. The present study established the design criteria, designed, manufactured and evaluated the performance of a real-time vision substitution device called VisionRE.

Knowledge obtained from a literature review of Human Machine Interfaces (HMIs), feedback from visually impaired focus groups and 3D electrode …

Functional Electrical Stimulation In Spinal Cord Injury Rehabilitation, Meir Hildeshaim

The Science Journal of the Lander College of Arts and Sciences

The following is an excerpt from the introduction to this article: Spinal cord injury is defined as a “disconnection syndrome” that results in a loss of ability of the spinal cord to communicate ascending and/or descending impulses (Hamid and Hayak 2008). Due to its role as the primary conduit of motor and sensory impulses, spinal cord injury is widely regarded as one of the most catastrophic, survivable injuries a person can suffer. Depending on the severity and placement of the injury, the patient can experience a wide range of disability or death. A mild injury may result in the patient …

Evaluation Of Niobium As Candidate Electrode Material For Dc High Voltage Photoelectron Guns, Mahzad Bastaninejad, Md. Abdulla Mohamed, Abdelmageed Elmustafa, P. Adderley, J. Clark, S. Covert, J. Hansknecht, C. Hernandez-Garcia, M. Poelker, R. Mammei, K. Surles-Law, P. Williams

Mechanical & Aerospace Engineering Faculty Publications

The field emission characteristics of niobium electrodes were compared to those of stainless steel electrodes using a DC high voltage field emission test apparatus. A total of eight electrodes were evaluated: two 304 stainless steel electrodes polished to mirrorlike finish with diamond grit and six niobium electrodes (two single-crystal, two large-grain, and two fine-grain) that were chemically polished using a buffered-chemical acid solution. Upon the first application of high voltage, the best large-grain and single-crystal niobium electrodes performed better than the best stainless steel electrodes, exhibiting less field emission at comparable voltage and field strength. In all cases, field emission …

Electrokinetic Flow In Polyelectrolyte–Modified Nanopores, L. H. Yeh, M. Zhang, Shizhi Qian, J. P. Hsu, S. W. Joo

Mechanical & Aerospace Engineering Faculty Publications

No abstract provided.

Implementation And Assessment Of A Virtual Reality Experiment In The Undergraduate Themo-Fluids Laboratory, Sushil Chaturvedi, Jaewan Yoon, Rick Mckenzie, Petros J. Katsioloudis, Hector M. Garcia, Shuo Ren

Mechanical & Aerospace Engineering Faculty Publications

Results are presented from an NSF supported project that is geared towards advancing the development and use of virtual reality (VR) laboratories, designed to emulate the learning environment of physical laboratories. As part of this project, an experiment in the undergraduate thermo-fluids laboratory course titled "Jet Impact Force" was transformed into a 3-D virtual reality experiment using the widely used MAYA R and VIRTOOLS R software. In order to facilitate students' interactions with the newly created 3-D interactive, immersive and stereoscopic virtual laboratory environment, the human computer interfaces (HCI) were programmed and incorporated in the simulation software. Two immersion levels …

Development Of Thermoelectric Temperature Sensors, Jennifer Jazmin Kuchle Ituarte

Open Access Theses & Dissertations

Temperature measurements in power generation systems can provide useful information on the performance parameters of the units. This paper presents a conceptual measurement technique using a simulated thermoelectric loop (signal transmitter). The transmitter simulates the induced current and magnetic field emanating from the center of an n and p loop. The receiver used in this study is a Hall Effect sensing device which measures the magnetic flux density produced by the transmitter. Three experimental setups were designed and built for the measurements. The first setup used a pendulum to move a coil simulating a loop thermoelectric generator thereby creating a …

Sustainable Riparian Restoration - The Utilization Of Sewage Effluent To Construct Wetlands Along The Rio Grande: A String Of Pearls Approach To Replenishment, Michael Earl Landis

Open Access Theses & Dissertations

The Rio Grande, from Elephant Butte Dam to El Paso, has been transformed from a free-flowing wild river into a highly engineered irrigation system. The Rio Grande Project, authorized by Congress in 1905, mandated the Bureau of Reclamation to store and deliver water exclusively to farmers. The river, maintained by the International Boundary and Water Commission, has been straightened and channelized between levees. The laws and policies governing the use of the waters of the Rio Grande are prohibitive to ecological restoration. Prior Appropriation doctrine allows for the exclusive use of these waters.

One sustainable tactic for replenishing the denuded …

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 …

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 …

Numerical Modeling Of Cds/Znxcd1-Xte Solar Cell, Farhana Anwar

Open Access Theses & Dissertations

Device modeling and simulation studies of CdS/ZnxCd1-xTe thin film solar cell have been carried out. A variety of graded band gap structures are examined. Incorporation of back electron reflector layer to improve open circuit voltage and carrier collection of CdTe solar cell was investigated. Device physics and performance determining parameters for different band gap profiles were analyzed. Based on simulation results, an optimal graded band gap structure for CdS/ZnxCd1-xTe solar cell is proposed. Performance of optimally graded band gap cell is superior to that of uniform bandgap cell.

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 …

Minimizing The Retransmission Delay And Energy Expense Of Arq With The Optimal Placement Of Caching Routers In A Video Communication Network, Jesus Enrique Hernandez

Open Access Theses & Dissertations

The use of intermediary caching routers to service retransmission requests was investigated in this thesis. The main goal is to reduce the expected retransmission delay in a video communication network where the capacity for intermediate caching routers is constrained. In order to reduce the retransmission delay, the effect of the placement of routers with caching ability is investigated. Moreover, as a consequence of reducing the retransmission distance, the energy spent on retransmitting video packets is reduced as well. The average retransmission delay and the average energy consumption were modeled with mathematical programs that select the optimal placement of caching routers …

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 …

Cryogenic System Development For Lox/ Hydrocarbon Propulsion Research, Francisco Pineda

Open Access Theses & Dissertations

A propulsion research facility is being developed at the Center for Space Exploration Technology Research (cSETR) at the University of Texas at El Paso (UTEP). These facilities were developed in order to meet new research demand for Liquid Oxygen (LOX)/Liquid methane (LCH4) experiments. The main goal of this system is to produce in-house liquid methane and supply propellants to their respective test set up in a cryogenic state. The work presented describes the design, development, and operation of a liquid methane condensation system and a cryogenic delivery feed system. The condensation system design will allow for a production of methane …

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 …

Investigation Of Gas-Solid Fluidized Bed With Non-Spherical Particles, Mario Alberto Ruvalcaba

Open Access Theses & Dissertations

The number of experimental and numerical studies of multiphase flows has remarkably increased over the last several years. This research has abundant applications in energy, chemical, and conversion processes. Common use of these technologies includes catalytic cracking for petroleum refineries, fluidized bed reactors (type of chemical reactor), interface modification, and has been an important technology breakthrough in coal gasification. The present work will concentrate on the investigation and validation of gas-solid flows utilizing numerical methods. The gas-solid flows study on this research assumes the solid and gas phases as continua with averaged properties.

The fluid flow computation was achieved using …

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 …

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 …

Modeling Power Consumption Of High Performance Computer Clusters, Mario Caire

Open Access Theses & Dissertations

This dissertation describes a utilization-based power modeling approach that makes use of the /proc file system and is applied to estimating power load and energy consumption of high performance computer clusters. A full cluster power model is specified that meets the following conditions: 1) provides accurate energy estimates; 2) consists of a minimal number of variables; and 3) the selected variables provide a sufficient degree of explanation of the primary OS level contributors to power consumption. The cluster power model is based on analysis at the system or compute-node level, where various models are developed and evaluated. All models described …

Impact Testing Of Zirconium Diboride, Mark David Flores

Open Access Theses & Dissertations

Refractory ceramic materials such as zirconium diborides (ZrB2) have been excellent candidate materials for application in turbine blades, leading edge surfaces of high mach aircraft and high temperature applications. This is due to their good strength at high temperatures (T>1800°C). But questions on their ultimate durability at such temperatures remains an issue, especially with respect to foreign object impact damage as well as oxidation. Little characterization of such materials of the impact durability of such materials at very high temperatures has been performed - In this talk an experimental approach for the impact testing of ceramic materials at elevated …