Digital Commons Network^™

Development Of Nanostructure Based Corrosion-Barrier Coatings On Steel For Transmutation Applications, Biswajit Das

Transmutation Sciences Materials (TRP)

Advanced transmutation systems require structural materials that are able to withstand high neutron fluxes, high thermal cycling, and high resistance to chemical corrosion. The current candidate materials for such structures are ferritic and ferritic-martensitic steels due to their strong resistance to swelling, good microstructural stability under irradiation, and the retention of adequate ductility at typical reactor operating temperatures.

In parallel, lead-bismuth eutectic (LBE) has emerged as a potential spallation target material for efficient production of neutrons, as well as a coolant in the accelerator system. While LBE has excellent properties as a nuclear coolant, it is also highly corrosive to …

Reactor Physics Studies For The Afci Reactor-Accelerator Coupling Experiments Project, Denis Beller

Transmutation Sciences Physics (TRP)

The specific research objective of this three-year project was to design and conduct accelerator driven experiments, to help demonstrate the ability to design, compute, and conduct ADS experiments and to predict and measure source importance, coupling efficiency, sub-critical reactor kinetics and source-driven transients. In addition, databases were created for both steady state and transient ADS experiments for the nuclear community to develop and test new computational codes and methods. The importance of a driving neutron source in various regions of different subcritical assemblies was mapped. Experiments were conducted and compared to calculations with radiation transport and thermal hydraulics codes such …

Immobilization Of Fission Iodine By Reaction With A Fullerene Containing Carbon Compound And Insoluble Natural Matrix, Spencer M. Steinberg, Gary Cerefice, David W. Emerson

Separations Campaign (TRP)

Observations related to the oxidation of iodide to iodine (I₂) or hypoiodic acid (HIO) by MnO₂ were continued. The formation of triiodide presumable involves the adsorption of iodide onto the MnO₂ surface (perhaps displacing a surface hydroxyl group). The iodide should be subsequently oxidized and released back into solution as IOH or I₂, which rapidly forms I₃ ^-. The kinetic data has been modeled as a first order process. First order rate constants have been obtained for the formation of iodine in the presence of MnO₂. The increase in iodide …

Evaluation Of Fluorapatite As A Waste-Form Material, Dennis W. Lindle, Oliver Hemmers, Dale L. Perry

Separations Campaign (TRP)

Argonne National Laboratory has proposed a new extraction procedure to handle TRISO-coated fuels, the Fluoride Extraction Process (FLEX). The FLEX process is designed to separate the uranium in the fuel from the actinides and most fission products by taking advantage of the unique properties of uranium hexafluoride (UF₆). In the FLEX process, the used TRISO fuel is reacted with zirconium fluoride salt, forming UF₆ and the fluoride salts of the actinides and fission products. At process temperatures, the UF₆ volatizes into a gas, and is released from the molten salt mixture. This leaves behind the actinides …

Electrochemical Separation Of Curium And Americium, David W. Hatchett, Kenneth Czerwinski

Separations Campaign (TRP)

The objective was to use electrochemical techniques to develop a thermodynamic understanding of actinide and lanthanide species in RTIL solutions, and use this data to effectively separate species with very similar chemical properties.

In consultation with a DOE collaborator, electrochemical methods and materials were evaluated and used to exploit the thermodynamic differences between similar chemical species enhancing the ability to selectively target and sequester individual species from mixtures. This project, in its third year, successfully completed phases 1, 2. Phase 3 was partially completed. The project expanded to include phase 4.

The following were specific goals for 2007-2008:

• To …

Fundamental Chemistry Of U And Pu In The Tbp-Dodecane-Nitric Acid System, Kenneth Czerwinski

Separations Campaign (TRP)

The research objective is to experimentally evaluate the fundamental speciation of Pu and U in the TBP-dodecane-nitric acid- AHA system and the effect of pertechnetate, specifically:

• To determine the influence of nitrate on the speciation of U and Pu in the TBP-dodecane-nitric acid system. The aqueous and organic speciation of U and Pu are examined as a function of the nitric acid concentration, nitrate concentration, actinide ion concentration, temperature, and time.

• To determine the speciation of U and Pu with AHA in the presence and absence of TBP-dodecane organic phase. The aqueous and organic speciation of U and …

Criticality Studies For Urex Processes, Denis Beller

Separations Campaign (TRP)

The completion of criticality experiments for mixtures of transuranic actinides (TRU; includes neptunium, plutonium, americium, and curium) that will be created during the separation of used nuclear fuel may be a requirement in order to construct prototype plants for the Global Nuclear Energy Partnership (GNEP). In this program and the Advanced Fuel Cycle Research and Development (AFC R&D) program that supports it, economic and environmental methods are being developed to reduce the impact of waste from commercial nuclear fuel cycles.

Recycling of used fuel by chemically separating it into U, fission products, and TRU would be the first step in …

F-Element Electrochemistry In Rtil Solutions: Electrochemical Separation Of Lanthanides And Actinides, David W. Hatchett

Separations Campaign (TRP)

Electrochemical methods can be used to effectively separate actinide and lanthanide species from complex mixtures. This is based on the unique electrochemical properties of each specific target species. In studies it has been found that, with the exception of Ce, aqueous solutions provide unsuitable electrochemical windows to effectively evaluate the thermodynamic properties that are useful for chemical separations. Therefore, a more novel approach was examined which eliminated the aqueous solution with a room temperature ionic liquid (RTIL) solution. RTIL solutions do not suffer from the side reactions that are prominent in aqueous environments. In addition, the potential window is much …

Evaluation Of Fundamental Radionuclide Extraction Data For Urex, Kenneth Czerwinski

Separations Campaign (TRP)

The speciation of technetium and actinides in advanced solvent extraction systems is the basis for their manipulation in separations. The ability to understand and predict radionuclide speciation is paramount to successful modeling of proposed separation systems. This project will examine the speciation of radionuclides in different stages of the uranium extraction (UREX) separation scheme, providing data useful to modeling. The areas to be examined include the speciation of uranium and plutonium with tributylphosphate and the kinetics and thermodynamics of lanthanides and actinides in the TALSPEAK (Trivalent actinide lanthanide separation by phosphorous reagent extraction from aqueous complexes) system. The complexation constants …

Separation Of Technetium From Uranium And Waste Form Synthesis, Kenneth Czerwinski

Waste Forms Campaign (TRP)

In this project, systematic investigations on the Tc-Zr binary metal system will be evaluated for the first time. The synthesis of metallic Tc as well as its alloys with Zr will be evaluated. In order to provide valuable data to AFC R&D, the thermodynamic equilibrium phases, as well as their performance under repository conditions, will be examined.

The research objectives of this project are as follows:

• Evaluate anion exchange methods for achieving the separation of Tc from U.

• Synthesize metallic Tc from the separated product.

• Synthesize and characterize Tc alloys.

• Investigate Tc-corrosion and Tc-leaching of binary …

Evaluation Of Cs/Sr Waste Form For Long Term Storage And Disposal, Gary Cerefice, Longzhou Ma

Waste Forms Campaign (TRP)

To facilitate long-term storage, the disposal containers will need to be able to survive for the entire storage interval. The first aspect of the project will explore the potential interaction of the aluminosilicate waste form with the storage canister materials to determine if there is any corrosion or chemical interaction concerns for the storage of the materials. At the end of the storage interval, most of the cesium (¹³⁷Cs) in the waste form will have decayed to its daughter, barium (¹³⁷Ba). While this decay provides a significant reduction in the decay heat generated by the waste …

Inside Unlv, Grace Russell, Diane Russell

Inside UNLV

No abstract provided.

Mojave Applied Ecology Notes Winter 2008, Scott R. Abella, E. Cayenne Engel, Jill E. Craig

Mojave Applied Ecology Notes

Mojave Desert collaborative projects, fire history in Spring Mountains, Northshore Road rehabilitation, wildfires and invasive plants in American deserts conference, weed sentry surveys

Analysis Of The Legal, Theoretical, And Practical Implications---Rumsfeld V Fair, Daryl Privott

UNLV Retrospective Theses & Dissertations

Congress has the power under Article 1 of the United States Constitution to "raise and support armies" and deems military recruiting on college campuses necessary for military preparedness and providing for the national defense. The Solomon Amendment was passed in 1994 and conditions the receipt of federal funds on access to college and universities for the purpose of military recruiting. This condition of federal funds led several law schools and faculty to bring suit against the Secretary of Defense claiming the Solomon Amendment violated their First Amendment rights. This case was heard in December 2005 and was ruled upon in …

The Characteristics, Knowledge, And Preparation Levels Of K--12 Online Distance Educators In The United States, Leanna Matchett Archambault

UNLV Retrospective Theses & Dissertations

With the increasing popularity and accessibility of the Internet and Internet-based technologies, along with the need for a diverse group of students to have alternative means to complete their education, there is a major push for K-12 schools to offer online courses. This is primarily occurring through offering virtual high school programs via online distance education. Virtual schools have been in existence since the proliferation of the Internet in the mid-1990s, and they continue to grow in popularity as a realistic alternative to traditional education. As the number of online distance education courses continue to proliferate throughout the nation, a …

A Qualitative Case Study Approach To Define And Identify Perceived Challenges Of Knowledge Management For Casino Hotel Industry, Ming-Lun Lee

UNLV Retrospective Theses & Dissertations

The overall goal of this study is to analyze and establish the importance of KM applications in the hotel industry, with two purposes in mind. The first is to explore hotel organizations' awareness and perceptions of KM applications. The second purpose is to identify casino hotel executives' perceived challenges of KM. Qualitative case studies and descriptive research designs with interviews were applied to accomplish the study objectives; Case study subjects' perceptions regarding KM definitions, KM functions, and expected benefits of KM were identified and discussed. Casino hotel executives perceive knowledge sharing, change resistance, and knowledge transfer major challenges of KM. …

The Development And Evaluation Of A Child Maltreatment Reporting Training Program For Mandated Mental Health Professionals, Krisann Marie Alvarez

UNLV Retrospective Theses & Dissertations

Despite a legal mandate to report suspected child maltreatment, the literature has consistently reported a failure by mandated professionals to report suspected maltreatment. Lack of knowledge regarding child maltreatment, reporting requirements and possible consequences of reporting have been cited as impediments to reporting. Previous research has recommended the development of training programs to address these hindrances. However, empirically validated training programs specific to the reporting of child maltreatment in mental health professionals have yet to be developed. Therefore, this study is the first to examine the efficacy of a child maltreatment reporting training program which addresses knowledge of child maltreatment …

Perceptions Of Gifted Education In Middle School And The Role Of Principal, James L Kuzma

UNLV Retrospective Theses & Dissertations

The purpose of this study is to determine the extent to which middle school principals are encouraging particular research-based practices relevant to teaching students with high ability in their buildings. In addition, the study will examine principals' and teachers' perceptions of principal practices related to the improvement in the achievement of gifted students in middle school; The study's design will utilize a mixed method using surveys and interviews. Quantitative methodology will be employed to gain and understanding of the perceptions of principals and teachers through the utilization of the survey. The study will also employ qualitative methodology by interviewing a …

The Effects Of Feedback Protocol And Learning Environment Perceptions On Self -Regulated Learning, Kevin David Biesinger

UNLV Retrospective Theses & Dissertations

The current research investigated the effects of differing feedback protocols in a multimedia learning environment to determine if changes would occur over time in goal orientation, self-regulation, self-efficacy or achievement. Subjects from an traditional undergraduate chemistry course were assigned to either a norm-referenced or self-referenced feedback group. Goal orientation and self-efficacy were measured via self-report surveys pre-post instruction, self-regulation was measured as the cumulative number of times each subject opened a worked example/self-explanation prompt while engaged in weekly web-based quizzes, and achievement was measured using final semester course grades. Perceptions of the learning environment were also probed as a potential …

The Effects Of Electromagnetic Fields On The Detection Of Mercury And Radionuclides, Yogendra M Panta

UNLV Retrospective Theses & Dissertations

Mercury and many radionuclides are extremely toxic, and their monitoring and detection are of importance for human health and environmental protection. This dissertation focuses on the detection of mercury (II) ions and radionuclides including uranium (234U and 238U), plutonium (239Pu), and americium (241Am) in aqueous solutions under the effects of electromagnetic fields. The stripping electrochemical method has been widely used to detect mercury (II) ions in aqueous solutions. To enhance the detection sensitivity of the conventional electrochemical method, mechanically stirring the solution is usually performed to enhance the rate of the ionic mass transport. Instead of mechanically stirring the solution; …

Development And Empirical Analysis Of A Self-Advocacy Readiness Scale With A University Sample, Katrina R Harris

UNLV Retrospective Theses & Dissertations

Counseling as a profession has been criticized for disregarding the social and political issues facing clients and students (Bemak & Chung, 2005). Many students in urban environments are faced with difficulties such as poverty, racism, and oppression that impact their emotional, social, and academic growth (Bemak & Siroskey-Sabdo, 2005). Further, students in urban schools feel they have little power in a school culture dominated by the majority group in which differences in culture, class and language are often perceived as deficits (Bryan, 2005); The No Child Left Behind Act calls for increasing achievement rates for all students and bridging the …

Preventing Campus Alcohol Abuse: A Controlled Comparison Of Two Media Programs, Jennifer Dawn Karmely

UNLV Retrospective Theses & Dissertations

Alcohol misuse on university and college campuses has contributed to a variety of problems experienced by students, including driving injuries and fatalities, alcohol poisoning, academic failure, potential long-term alcohol abuse, and risky or nonconsensual sexual activity. This investigation examined the efficacy of two prevention programs targeting campus alcohol misuse (Alcohol 101; Collegiate Guide to Responsible Drinking, CGRD). Alcohol 101 disseminates information regarding the consequences of alcohol abuse in a psycho-educational, interactive DVD format. CGRD includes some DVD-based psycho-educational material while primarily focusing on empirically derived cognitive behavioral techniques. Ninety-two participants recruited from university psychology courses were randomly assigned to receive …

Modeling Natural Resource Scarcity And Poverty Effects On Fertility In Honduras, Nepal, And Tanzania, Ayoub Shaban Ayoub

UNLV Retrospective Theses & Dissertations

This dissertation examines whether the vicious circle theory applies in three developing countries characterized by high population growth. According to the vicious circle theory, natural resource scarcity coupled with poverty leads to population growth via positive effects on fertility particularly in rural areas of developing countries. Population growth then leads to a further increase in natural resource scarcity, creating a "feedback loop." This is the first study to use micro-level data to test and control for endogeneity using a two-stage Probit model (IVPROBIT). The existing literature has largely failed to address endogeneity in the relationship between natural resource scarcity and …

The Effects Of Mushroom Body Lobe Disruption On Learning And Memory, Brian S Dunkelberger

UNLV Retrospective Theses & Dissertations

Animal models have been used for centuries to study learning and memory in simple systems with many applications to humans (Chapter 1). The fruit fly Drosophila melanogaster has added greatly to our current understanding of learning and memory and its underlying biology (Chapter 2). The research described here focuses on the relationship between learning and memory and the brain using three mutant strains of flies: mushroom body miniature B (mbmB), small mushroom bodies (smu), and mushroom bodies reduced (mbr). Mushroom bodies are paired neuronal structures found in most invertebrate brains involved in learning and memory consolidation. All three mutations studied …

Temporal Orientation And Consumer Empowerment: Examining A Las Vegas Casino Loyalty Program, Flavia Hendler

UNLV Retrospective Theses & Dissertations

This study examines how temporal orientation impacts perception of a loyalty program. It examines how control over loyalty program features impacts the subjective experience of empowerment for customers with three temporal orientations: Present-Hedonistic (PH), Present-Fatalistic (PF), and Future-Oriented (FO). The study analyzes whether future-oriented individuals evaluate the more long-term and abstract levels associated with choice, while present-oriented individuals look for concrete details and the more immediate benefits of their consumption experience. A qualitative technique, the Zaltman Metaphor Elicitation Technique (ZMET), is used in order to capture the conscious and unconscious meanings associated with a casino loyalty program by members of …

Predicting Evapotranspiration From Sparse And Dense Vegetation Communities In A Semiarid Environment Using Ndvi From Satellite And Ground Measurements, Malika Baghzouz

UNLV Retrospective Theses & Dissertations

One of the most critical issues associated with using satellite data-based products to study and estimate surface energy fluxes and other ecosystem processes, has been the lack of frequent acquisition at a spatial scale equivalent to or finer than the footprint of field measurements. In this study, we incorporated continuous field measurements based on using Normalized difference vegetation index (NDVI) time series analysis of individual shrub species and transect measurements within 625 m2 size plots equivalent to the Landsat-5 Thematic Mapper spatial resolution. The NDVI system was a dual channel SKR-1800 radiometer that simultaneously measured incident solar radiation and upward …

Magnetohydrodynamics In Microchannels And Adhesion Properties Of Nanoporous Alumina Films, Hussameddine Kabbani

UNLV Retrospective Theses & Dissertations

In the first part of this dissertation, RedOx-based magnetohydrodynamic (MHD) flows in three-dimensional (3D) microfluidic channels are investigated theoretically with a coupled mathematical model consisting of the Nernst-Planck equations for the concentrations of ionic species, the local electroneutrality condition of the electric potential, and the Navier-Stokes equations for the flow field. The induced currents and flow rates in 3D planar channels are compared with the experimental data obtained from the literature and those obtained from the previous two-dimensional mathematical model. Then a new approximate closed form solution for the velocity profile of steady incompressible MHD flows in a rectangular micro-channel …

A Multi -Case Study Of Teacher Retention With Veteran Teachers In Hard To Staff Schools, Jacqueline Lissette Garcia

UNLV Retrospective Theses & Dissertations

Over 40 percent of teachers leave the profession within the first five years (Darling-Hammond, 2003; Berry, 2004), and turnover is higher in schools characterized as hard to staff (Ingersoll, 2001). Hard to staff schools often have higher attrition rates, and also have a higher percentage of under qualified teachers (Berry, 2004). The need to retain highly qualified teachers in teaching positions in hard to staff schools is critical because teachers are less likely to continue to teach in schools characterized as such. A multi-case study design was employed to investigate four teachers who have taught in hard to staff schools …

An Exploratory Study Of Proximal Mentoring In Graduate Education, Susan E Gunn

UNLV Retrospective Theses & Dissertations

This dissertation explored the construct of Proximal Mentoring from the perspective of the professor, student-mentees, and Proximal Mentors. A master's course and a beginning doctorate course were selected for implementation. All participants were in agreement that the definition of the role of Proximal Mentoring is: "provider of content and feedback, model for collaboration, clarifier of course objectives, guide, and role model." None of the participants in this study perceived the role of the PM as a tutor. However, they did not see the role as an expert mentor either. This dissertation suggested that PMs were able to increase their depth …

Avoiding The Sexual: Visual Attention And Distraction In Dyspareunia, Amy D Lykins

UNLV Retrospective Theses & Dissertations

Dyspareunia, defined as genital pain associated with intercourse, holds the unenviable status of being one of the most prevalent yet understudied of the sexual dysfunctions. The coupling of sex and pain creates an interesting theoretical conundrum of clinical significance: are women with dyspareunia distracted from sexual stimuli (as the sexual dysfunction literature would suggest), or are they hypervigilant to sexual stimuli because these stimuli elicit thoughts and expectations of pain (as the pain literature would suggest)? Eye-tracking may be a uniquely relevant tool to measure potential differences in attention between women with and without dyspareunia. The current study tested distraction …