University Of Texas At Arlington Research Articles

A prediction and load shed-based approach of controlling a medium voltage AC/DC testbed

Shipboard power systems have previously relied on oversized generators with minimal monitoring of the output, preventing the implementation of many real-time controls. Redundant generation is implemented instead of controls, resulting in uncontrolled load sheds when capacity is exceeded, or generators fail. The naval power system community is extensively studying the advantages of distributed zonal power system architectures that allow for the buffering of multiple generation sources and loads using energy storage and regulating power electronics. Extensive sensing and controls are necessary for successful operation of a distributed power system, and they must be evaluated adjoint to representative hardware topologies. The University of Texas at Arlington (UTA) is utilising a medium voltage (MV) AC/DC testbed to examine predictive high ramp rate (PHRR) and advanced load shed (ALS) control algorithms developed and modelled by Clarkson University (CU). A single zone of a zonal power system is being emulated using UTA’s testbed. Experimental results collected after integrating the CU control strategies into the UTA testbed will be discussed here.

University of Texas at Arlington (UTA) In-house Covid-19 Testing Program

The pandemic caused by the spread of the virus SARS-CoV-2 threatened to severely disrupt the activities of student-athletes. In order to provide a safe environment for athletic competition, the National Collegiate Athletic Association (NCAA) mandated testing of student-athletes. The goal was to rapidly identify student-athletes and the athletic staff member who either tested positive for SARS-CoV-2 or were in contact with individuals who tested positive. Rapid identification of infected individuals and their contacts allowed the University to implement quarantine standards and quarantine facilities quickly as needed. The University of Texas at Arlington (UTA) developed an in-house testing program and was quickly able to meet the NCAA requirements, allowing UTA to continue its athletic participation with minimal forfeiture of scheduled games. The purpose of this paper is to report the implementation UTA's COVID prevention program for the university's athletic program. This program may provide valuable information to other universities' planning for the management of COVID prevention in their athletic programs. Challenges and solutions are identified.

Launching PLTL for MATH: Building on the Foundation of Supplemental Instruction

The paper describes the launch of Peer-Led Team Learning for Precalculus Engineering and Math at the University of Texas at Arlington (UTA) and the results that PLTL has had on pass rates. Historically, students placed into Precalculus, instead of being Calculus ready, have experienced higher failure rates than any other student grouping. While UTA has invested in many studies, programs and techniques that aid these underprepared students, a few strategies have emerged as being effective. These strategies have included the previous implementation of Supplemental Instruction (SI), with separate sections devoted specifically to Precalculus co-enrolled engineering-course students, peer-based instruction, and active learning activities as opposed to additional lectures. As a result of these findings, in the Fall 2020 semester, UTA combined all these strategies into a learning course integrating these best practices into a required PLTL learning lab with problem-based activities and studying practices for the engineering course and a self-selected PLTL option for the math course. The goal was to aid in increasing success rates in these classes. The students engaged in effective “study habits” and problem-based learning practices with a Peer-Led Team Learning (PLTL) leader. What we have found is the positive impact that PLTL has on pass rates for at-risk populations in addition to positive satisfaction surveys. This paper will show the effectiveness of PLTL by discussing success rates for the Fall 2020 and Spring 2021 semesters versus the other singular implementations from previous semesters, in this case Supplemental Instruction.

Ceramic Insulated Slug Calorimeter for High- Enthalpy Flows

This work presents an approach to the design, and successful experimental validation, of a slug-type calorimeter for long-duration high-enthalpy flows. Specifically, a ceramic shell is used to insulate the slug. Although slug calorimeters have been widely used in arcjets for decades, significant uncertainties are known to be associated with these instruments, which directly affect the uncertainty of critical derived flow quantities such as specific enthalpy. A detailed analysis of the newly proposed design approach is presented. Particular attention has been devoted to the minimization of heat losses from the slug to the shroud, one of the major contributors to the instrument’s uncertainty. The effect of the shroud geometry, insulation thickness, and slug dimensions have been investigated numerically; variable thermophysical properties, nonuniform heat fluxes, and radiation were considered. The analysis showed that the shroud geometry plays a significant role in the heat losses. Based on this design approach, a calorimeter was manufactured to be used in the Office of Naval Research (ONR)–University of Texas at Arlington (UTA) arc-heated wind tunnel “Leste” facility. Experimental measurements in flows with bulk enthalpies up to 4 MJ/kg showed good agreement with the numerical simulations, and measured heat losses were well below the American Society for Testing and Materials standard recommendation.

Demonstration of a prototype design synthesis capability for space access vehicle design

ABSTRACTThe early conceptual design (CD) phase of space access vehicles (SAVs) is the most abstract, innovative and technologically challenging phase of the entire aerospace design life cycle. Although the design decision-making during this phase influences around 80 percent of the overall life cycle cost, it is the most abstract and thus least understood phase of the entire design life cycle. The history of SAV design provides numerous examples of project failures that could have been avoided if the decision-maker had had the capability to forecast the potential risks and threats correctly ahead of time during the conceptual design phase. The present study addresses this crucial phase and demonstrates a best-practice synthesis methodology prototype to advance the current state of the art of CD as applied to SAV design. Developed by the Aerospace Vehicle Design (AVD) Laboratory at the University of Texas at Arlington (UTA), the Aerospace Vehicle Design Synthesis process and software (AVDS) is a prototype solution for a flight vehicle configuration–flexible (generic) design synthesis capability that can be applied to the primary categories of SAVs. This study focusses on introducing AVDS, followed by the demonstration and verification of the system’s capability through a sizing case study based on the data-rich Boeing X-20 Dyna-Soar spaceplane.

Five Episodes of Urban Discovery as a Student Recruitment Strategy in Planning

The literature on graduate-level studio and capstone courses, and the steady decline in student enrollment in recent years demand creative pedagogies to lure undergraduate students into planning. This paper explores the role of self-discovery at the undergraduate level as a conduit toward increasing student recruitment. Forty-seven University of Texas at Arlington (UTA) non-planning major students examined five episodes of urban discovery in the Dallas–Fort Worth (DFW) Metro area in two consecutive semesters. Post-course evaluations show how both student cohorts reflected upon their learning outcomes, and at least 27 percent of the twenty-six respondents expressed eagerness to pursue planning graduate degrees.

Career Progression for Librarians and Archivists Without Faculty Status: A New Model

In 2013, the dean of Libraries at the University of Texas at Arlington (UTA) Libraries formed a task force composed of six librarians and charged them with completely overhauling the career progression policy for librarians and archivists that had been in place since 1995. The task force devised a new policy and a scoring rubric to assist the committee that makes recommendations regarding promotions in their evaluation process. This article describes the process of developing the policy and its accompanying rubric as well as their contents and recounts lessons learned during the first round of evaluations of candidates for promotion.

Fuzzy logic control of a hybrid energy storage module for use as a high rate prime power supply

Hybrid Energy Storage Modules (HESM) have emerged as a possible energy storage device for naval pulsed power applications [1–6]. A HESM combines energy dense and power dense devices to offer a holistic solution for repetitive loads that are highly transient in nature. Actively controlled power electronic converters are used to regulate the power that flows from each energy storage or generation source to a point of common coupling. In these types of naval applications, it is likely that the system will be comprised of components that are available as commercially off the shelf (COTS) components, though some may be custom designed as well. Combining COTS components in a HESM can be challenging because system-level control must be imposed on top of individual device control. Previous work at the University of Texas at Arlington (UTA) has demonstrated a basic model of a HESM and a fuzzy logic systemlevel controller through software simulation. Building on the work by UTA, this paper will validate a model of a Hybrid Energy Storage Module with fuzzy logic system-level control under the effects of a transient pulsed power load.

Low energy positron beam system for the investigation of 2D and porous materials

An advanced variable energy positron beam (~2 eV to 20 keV) has been designed, tested and utilized for coincidence Doppler broadening (CDB) measurements at the University of Texas at Arlington (UTA). A high efficiency solidified rare gas (Neon) moderator was used for the generation of a slow positron beam. The gamma rays produced as a result of the annihilation of positrons with the sample electrons are measured using a high purity Germanium (HPGe) detector in coincidence with a NaI(Tl) detector. Modifications to the system, currently underway, permits simultaneous measurements utilizing Positron annihilation induced Auger Electron Spectroscopy (PAES) and CDB. The tendency of positrons to become trapped in an image potential well at the surface will allow the new system to be used in measurements of the chemical structure of surfaces, internal or external and interfaces. The system will utilize a time of flight (TOF) technique for electron energy measurements. A 3m flight path from the sample to a micro-channel plate (MCP) in the new system will give it superior energy resolution at higher electron energies as compared to previous TOF systems utilizing shorter flight paths.

Using Internal Pressure Measurements to Fundamentally Understand the Aging of Lithium-Ion Batteries

The sealed nature of lithium-ion batteries makes the in-situ study of their aging mechanisms challenging at best. Typically voltage, current, thermal, and impedance diagnostics are used to characterize cell aging mechanisms as they are cycled and post mortem analysis reveals the most compelling information however further cycling of the cells is of course prohibited. While these are promising, they do not reveal the full story. At the University of Texas at Arlington (UTA), research has been performed to evaluate how cell pressure can be used as a diagnostic to better understand cell aging mechanisms at elevated rates. The cells are punctured in an inert environment and inserted into a sealed chamber where they can be cycled while measuring their internal pressure. The studies presented here have shown a strong correspondence between capacity fade and pressure rise in LiCoO2 cells across a few different rates. These results as well as some ongoing work in which LiFePO4 cells are being studied will be presented. Analysis of the impedance growth as well as the gas generated while cycling the cells will also be discussed.

Design and Characterization of an Actively Controlled Hybrid Energy Storage Module for High-Rate Directed Energy Applications

There is considerable need for a mobile, reliable, efficient, and compact prime power supply for a host of applications, including directed energy and electrical grid backup among others. Electrochemical energy storage devices, which possess either high-power density or high-energy density, have been developed recently and are very applicable for use in these applications. The need for both high energy and high power, however, makes the design and implementation of such a prime power supply a nontrivial task. While lithium-ion batteries (LIBs) are available, which possess both high power and energy density, operation at high power reduces their cycle life, decreasing the reliability and increasing the cost of the system when replacement becomes necessary more frequently. One proposed method involves optimally combining high-energy batteries with high-power electric double layer capacitors (EDLCs) using actively controlled power electronics to regulate the current to and from each respective device. In such a scheme, energy can be slowly sourced to and from the batteries, while the capacitors are used to supply or accept the bulk of the current when the demand is high, especially during fast transients. This type of scheme should not only maximize the batteries' cycle life and ensure that both the energy and power required of the load(s) is always available, but will also increase the instantaneous power capabilities of the system, offering a well-rounded solution to sourcing steady and/or transient loads. When augmenting a fossil fuel generator with a hybrid energy storage module (HESM), the HESM has the ability to act as a high-energy reservoir that can harvest energy from the generator when the loads are in short periods of inactivity. This enables the generator to be continuously base loaded, thereby maintaining a high level of efficiency at all times, while theoretically maintaining the required power quality of the main ac bus. At the University of Texas at Arlington (UTA), an actively controlled, high-rate HESM has been constructed to evaluate its performance under the typical load condition presented by directed energy weapons. It has been assembled using LIBs, EDLCs, and commercial off-the-shelf power electronic converters. A discussion about the future of HESMs, the experimental setup at UTA, and the results obtained thus far will be presented here.

Design and Active Control of a Microgrid Testbed

Researchers at the University of Texas at Arlington (UTA) have installed a novel Microgrid testbed architecture that will be used for educational and research purposes. This paper documents the architecture of the UTA grid, the development of the national instruments based active control system, and some of the research progress made thus far. The specific commercial off the shelf components that make up the hardware in the system, which is actually broken up into three independent smaller grids, is described. A custom interconnection architecture will also be discussed that enables the three individual Microgrids to operate independently or in an actively interconnected mode of operation. The implementation of system control software will be presented in terms of the state machine used to develop the software. Finally, experimental data gathered from the dynamic performance of the Microgrid will be presented.

Library Reorganization, Chaos, and Using the Core Competencies as a Guide

Starting in the fall of 2012, the staff at the University of Texas at Arlington (UTA) Library began to plan for a library-wide reorganization of staff and services. Every staff member would be affected by the reorganization process, including the library’s serials and e-resources team. In what could be a most chaotic time, the serials and e-resources team chose to use the North American Serials Interest Group (NASIG) draft version of core competencies for electronic resource librarians as a guide to help in selecting members for the e-resources team that would emerge following the reorganization. The presentation on which this article is based reviews the situation at UTA, the core competencies, and how the serials/e-resources team used the core competencies along with a self-assessment tool to help select the most qualified staff for the team.

Evaluation of High C Rate Cycle Induced Aging on Low Impedance Lithium-Ion Batteries Using In-Situ Electrochemical Impedance Spectroscopy (EIS) Analysis

The University of Texas at Arlington (UTA) has performed experiments in which high power 3Ah LiNixCoyAl1-x-yO2 batteries have been studied at high C rates. The first of three identical cells has been discharged using a 10 kHz (50% duty cycle), high C rate (100C/300 A) pulsed discharge procedure and a 1C constant current (CC) - constant voltage (CV) recharge procedure. The second cell has been discharged using a 1C CC procedure and recharged using a 111 mHz (33% duty cycle), high C rate (33C/100 A) pulsed recharge procedure. The third cell, the control cell, has been cycled using a 1C CC discharge procedure and 1C CC-CV recharge procedure. The results of these experiments enable the impact each respective high rate procedure has on cell aging to be better understood. The experimental procedures and methods will be discussed in detail and the results of the experiments will be presented.

JANUARY 2014 PLACEMENT ADS

JANUARY 2014 PLACEMENT ADS

Nursing Poetry

Kristina Ibitayo, MSN, RN, was a PhD nursing student at the University of Texas at Arlington (UTA) in Arlington,Texas, and an editorial assistant for the Journal of Child and Adolescent Psychiatric Nursing, and she worked as a graduate research assistant at UTA at the time these poems were written.

EDITORIAL - Joint Meeting 9th International Symposium on New Materials and Nano-Materials for Electrochemical Systems and XII International Congress of the Mexican Hydrogen Society

The Joint Meeting 9th International Symposium on New Materials and Nano-Materials for Electrochemical Systems and XII International Congress of the Mexican Hydrogen Society, “Challenges in New Materials Development for Sustainable Energy and Transport”, was held in Merida, Yucatan, Mexico, on July 8-13, 2012. It served as a forum to disseminate the latest developments in relevant topics such as Advanced Batteries, Fuel Cells, Photoelectrochemical Cells, Hydrogen Production and Storage, among others.
 
 The Event was hosted by the Mexican Hydrogen Society (MHS). Founded in 1999, the MHS is nowadays the leading organization within Mexico bringing together Research Groups, Government Agencies and Industry partners to promote R&D related to hydrogen technologies. 
 
 Plenary lectures were delivered by Prof. Nicolas Alonso-Vante from University of Poitiers (France), Prof. Perla B. Balbuena from Texas A&M University (USA), Prof. Bruce Parkinson from University of Wyoming (USA), Prof. Krishnan Rajeshwar from University of Texas At Arlington (USA), Prof. James J. Spivey from Louisiana State University (USA) and William Whittenberger from EcoLake Enterprises, LLC, Ohio, (USA). 
 
 The Meeting included 62 oral presentations and 73 works at the poster sessions of delegates from Mexico, Canada, France, Argentina, Spain, Turkey, USA, China, Japan, Brazil, Venezuela, Portugal.
 
 This special issue of the Journal of New Materials for Electrochemical Systems includes selected papers presented at the Meeting, covering different important topics: Supercapacitors, Microbial Fuel Cells, Surface modification of polymer electrolytes, Capacitance studies, Materials for hydrogen evolution and hydrogen production, Dye-sensitized solar cells, Novel fuel cell membranes, Low Pt-content catalysts for PEMFCs anodes and cathodes, Autothermal Reforming of Ethanol, Steam Reforming of Biofuels, Anode electrocatalysts for DAFCs, 
 
 We wish to thank the Consejo Nacional de Ciencia y Tecnología (National Council for Science and Technology of Mexico, CONACyT) for the financial support that made possible the 9th International Symposium on New Materials and Nano-Materials for Electrochemical Systems and XII International Congress of the Mexican Hydrogen Society. Also, we extend our gratitude to Prof. O. Savadogo, Editor-in-Chief of the Journal, for encouraging the publication of this Special Issue. Also, we thank all of the authors for their contributions and to the referees for their comments and suggestions.
 
 The 10th International Symposium on New Materials and Nano Materials for Electrochemical Systems will be held in Montreal in July 5-8, 2015 
 
 The XIV International Congress of the MHS will be held in Cancun, Mexico, in 2014. For more information, please visit the MHS´s official webpage: www.smh2.mx.

Transportation infrastructure settlement and heave distress: challenges and solutions

Transportation agencies spend millions of dollars annually to repair civil transportation infrastructure including pavements, earth structures and approach slabs distressed by soft compressible soils and expansive soils. Several research studies performed at the University of Texas at Arlington (UTA) focused on stabilizing these problematic soils so that they will provide better and more stable support to the transportation infrastructure. This paper focuses on a summary of two major distresses and mechanisms, and remedial measures for addressing these distress problems. A combined lime-cement stabilization method is fully evaluated in providing better support of pavement infrastructure, and these results are described here. Another major transportation infrastructure problem involving bridge approach slabs requires different treatment methods, and these results are briefly described. As a part of the recently completed research study assessments, both shallow and deep soil treatment methods for stabilizing soils are fully evaluated for their effectiveness in arresting the distress posed to the pavements and bridge approach slabs. These results along with a few future research needs are presented in this paper.

A REVIEW OF ENHANCEMENT OF BOILING HEAT TRANSFER THROUGH NANOFLUIDS AND NANOPARTICLE COATINGS

This review traces the development of nanofluid pool boiling from its beginning (1984) to the present through a sampling of studies that have interested the authors and which have led to the latest findings at the University of Texas at Arlington (UTA). The studies of thermophysical properties of nanofluids are briefly covered. Several works in the last 7 years are highlighted to illustrate the modes of nanofluid pool boiling testing, the variability of nanofluid boiling heat transfer (BHT), and the postulations of causes of this behavior. Starting in 2006, the wettability increase in the nanoparticle coating, generated during the nanofluid pool boiling, is recognized as the source of critical heat flux (CHF) enhancement through its effect on the dynamics of hot spots and departing bubbles. The reasons for the observed contradictory BHT behavior are not yet fully clear, but recently at UTA, nanofluid boiling heat transfer has shown to be transient due to the dynamic nature of the formation of the nanoparticle coating. Also at UTA, the mechanism of nanoparticle deposition on the heated surface has been further confirmed. Thus, nanofluid boiling has led back to heat transfer enhancement through surface modification in nanoscale. These developments from 2006 are covered in more detail.

Management of Information Security

Click to increase image sizeClick to decrease image size Additional informationNotes on contributorsJoseph S. MollickJoseph S. Mollick is an assistant professor of management information systems at the College of Business at Texas A&M University, Corpus Christi (TAMU-CC). He earned the PhD degree in business administration from Southern Illinois University Carbondale (SIUC). His major field of study was information systems and minor fields were organization theory, business strategy and statistics. In addition to the PhD, he has two master’s degrees and two bachelor’s degrees. He earned a master of sciences degree in information systems from the University of Texas at Arlington (UTA). For the master of business administration (MBA) and the bachelor of business administration (BBA) degrees he studied at Saint Edward’s University, Austin, Texas. His bachelor of arts (BA) degree from Notre Dame College (NDC), Dhaka, Bangladesh, was in the humanities--economics, social welfare, language and literature. His research interest is in the intersection of strategy, law and ethics of managing information and knowledge resources. Before coming to TAMU-CC, he taught at SIUC, UTA and Notre Dame College. His research articles have been published in journals such as the Journal of International Technology and Information Management, Journal of Information Privacy and Security, The Journal of Academic Administration in Higher Education, and Issues in Information Systems.