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Radiation Transport Modeling Of Beam-Target Experiments, William Culbreth, Denis Beller

Reactor Campaign (TRP)

In the first year of the UNLV effort, researchers planned to develop the models of the experimental systems to predict the neutron flux and leakage from the experimental targets using the MCNPX code suite in order to help determine these missing parameters. To support these models, the researchers project, or estimate, values for the unknown parameters describing various events and phenomena occurring within the beam-target experiment. The results of these simulations will then be compared against the observed neutron leakage rates and energies. The estimates for the unknown parameters are then revised to correlate with the observed values (these parameters …

University Of Nevada, Las Vegas Transmutation Research Program Annual Report 2001, Anthony Hechanova, Elizabeth Johnson, Gary Cerefice

Transmutation Research Program Reports (TRP)

The UNLV Transmutation Research Program was established in March 2001 as part of the national Advanced Accelerator Applications program to develop the technologies necessary for the ecological and economical treatment of spent nuclear fuel.

The primary role of the UNLV program in the national effort is the training of graduate and undergraduate students in nuclear engineering and other related fields to support the augmentation of the U.S. human infrastructure for transmutation technologies.

To accomplish this role, UNLV has developed the TRP with the primary focus of supporting student research into transmutation and supporting technologies. This focus is realized through the …

Modeling, Fabrication, And Optimization Of Niobium Cavities, Robert A. Schill Jr., Mohamed Trabia, Yitung Chen

Transmutation Sciences Materials (TRP)

All technologies for the transmutation of nuclear waste require a large source of neutrons. One of the principal methods of generating these neutrons is by using a particle accelerator to bombard a heavy metal target. One of the more promising designs for particle accelerators for transmutation systems is the Superconducting Radio Frequency (RF) high-current linear accelerator (linac). The power supplies for these systems have three major components: niobium cavities, power couplers, and cryomodules. This research project will develop models to predict the behavior and performance of the niobium cavities, which will then be used to design and optimize the superconducting …

Experimental Investigation Of Steel Corrosion In Lead Bismuth Eutectic (Lbe): Characterization, Species Identification, And Chemical Reactions, John Farley, Dale L. Perry, Allen L. Johnson

Transmutation Sciences Materials (TRP)

The goal of the present research is to achieve a basic understanding of corrosion of steels by Lead Bismuth Eutectic (LBE). Liquid LBE is under consideration in the transmuter as both a spallation target and as a blanket coolant. There have been previous studies of LBE, especially by the Russians, who have over 80 reactor-years experience with LBE coolant in their Alpha-class submarine reactors. However, a fundamental understanding and verification of its role in the corrosion of steels is still very incomplete. We have begun a program of post-experiment testing and analysis on steel samples that have been in intimate …

Corrosion Of Steel By Lead Bismuth Eutectic, John Farley, Dale L. Perry, Allen L. Johnson

Transmutation Sciences Materials (TRP)

This research program will analyze various steel samples that have been exposed to LBE as part of the national program to develop LBE and transmutation technologies. This information will be paramount in developing engineering efforts to control, avoid, and/or minimize the effect of corrosion of steels by LBE in transmuter and LBE systems. Additionally, this program provides UNLV researchers with hands-on experience that will be crucial in developing the UNLV LBE program, supporting the University’s mission with the ISTC target complex, and the future development of additional facilities to examine LBE systems.

The research group plans to test the hypothesis …

Corrosion Of Steel By Lead Bismuth Eutectic: Year 1 Annual Report, John Farley

Transmutation Sciences Materials (TRP)

The goal is to investigate the corrosion of stainless steel by lead-bismuth eutectic (LBE), which has been proposed for use as a blanket coolant and a spallation target in the transmuter.

Hydrogen-Induced Embrittlement Of Candidate Target Materials For Applications In Spallation-Neutron-Target Systems, Ajit K. Roy, Brendan O'Toole, Zhiyong Wang, David W. Hatchett

Transmutation Sciences Materials (TRP)

Spallation-neutron-sources, such as those under investigation for use in accelerator-driven transmutation systems, generate neutrons through the collision of high-energy protons, or charged hydrogen atoms, with heavy metal targets such as lead. As a result, these systems also tend to deposit a significant amount of hydrogen in the materials of the transmuter target and superstructure. This can result in accelerated corrosion and changes in the properties of the exposed materials. Of particular importance is a phenomenon called hydrogen embrittlement, in which materials lose their ductility (ability to deform under stress) and become brittle (more susceptible to fracture) after reacting with hydrogen. …

Modeling Corrosion In Oxygen Controlled Lbe Systems With Coupling Of Chemical Kinetics And Hydrodynamics: Task V 4th Quarterly Report, Samir Moujaes

Transmutation Sciences Materials (TRP)

The project is moving on target with the newly realigned objective set for the Phase I. Through close communications with Dr. Li and Dr. Jinsuo Zhang from LANL a realignment of the simulation work has been recommended. The reason for that is the vendor of STAR-CD/CHEMKIN had not perfected yet the final coupling of the post processing of output for any potential surface chemistry reaction taking place on the inside pipe surface of the LBE loop. This is because the coupling of CHEMKIN and STAR-CD has been done fairly recently.

Our final effort has been to generate using an innovative …

Modeling Corrosion In Oxygen Controlled Lbe Systems With Coupling Of Chemical Kinetics And Hydrodynamics, Samir Moujaes, Yitung Chen

Transmutation Sciences Materials (TRP)

Many of the international efforts to develop transmutation technology, including the U.S., Russian, and European scientific communities, have determined that lead bismuth eutectic (LBE) is a potential material for use as a both a spallation target and a coolant. To exploit this potential, a more thorough understanding of the effect and rates of corrosion on steels, particularly non-Russian alloys, inside the LBE systems is required. Properly controlling the oxygen content in LBE systems has been observed to drastically reduce the corrosion of structural steels in LBE. However, the transport of oxygen and formation of corrosion products is not well understood; …

Development Of A Mechanistic Understanding Of High-Temperature Deformation Of Alloy Ep-823, Ajit K. Roy, Brendan O'Toole

Transmutation Sciences Materials (TRP)

Alloy EP-823 has been developed as a structural material for Lead Bismuth Eutectic (LBE) systems, such as those under development for nuclear transmutation systems, as well as other applications. However, very little data regarding the mechanical properties of this alloy exists in the open literature, particularly in the temperature regime of interest for transmutation systems. To address this need, the UNLV research team, in collaboration with researchers from Los Alamos National Laboratory, has developed a research program to evaluate tensile properties of Alloy EP-823 stainless steel at elevated temperatures, which is not being performed at any other facility to date. …

Neutron Multiplicity Measurements Of Target/Blanket Materials, Carter D. Hull, William H. Johnson

Transmutation Sciences Physics (TRP)

To begin developing the database necessary for the validation and benchmarking of the LAHET component of the MCNPX code suite, the UNLV research program has set forth the following objectives. First, the current MCNPX suite will be used to develop models of multi-element neutron detector systems. These models of the detector systems will be incorporated into the design of detailed models for the entire detector-target system. These models will first be used to help design the irradiation experiments, and then will be used to model the behavior of the system. Irradiation experiments corresponding to the detector-target system models will be …

Development Of Dose Conversion Coefficients For Radionuclides Produced In Spallation Neutron Sources, Phillip W. Patton, Mark Rudin

Transmutation Sciences Physics (TRP)

For the first year of this effort, the UNLV research team set out four objectives. First, the university and laboratory consortium had to be established. This consortium was tasked with helping to determine the methodology for determining the dose coefficients, and to ensure that the resulting DCs will be of use to the national programs developing accelerator-driven nuclear systems (such as the SNS or an accelerator-driven transmutation system) and to the health physics community as a whole. The second goal of this program was to determine a methodology and then prioritize the radionuclides so that the research effort would address …

Development Of Dose Coefficients For Radionulides Produced In Spallation Neutron Sources: Annual Report, Phillip W. Patton, Mark Rudin

Transmutation Sciences Physics (TRP)

The University of Nevada, Las Vegas (UNLV) Transmutation Research Program has been tasked to support U.S. Department of Energy (DOE) efforts to assess the health risks associated with the operation of each of their accelerator-driven nuclear facilities for both NEPA and PSAR development. Quantifying the radiological risks to workers will have to be addressed during the design and siting of each of these facilities. U.S. Environmental Protection Agency (EPA) Federal Guidance Report No. 11 “Limiting Values of Intake and Air Concentration and Dose Conversion Factors for Inhalation, Submersion, and Ingestion”, developed two derived guides, Annual Limit on Intake (ALI) and …

An Interdatabase Comparison Of Nuclear Decay And Structure Data Utilized In The Calculation Of Dose Coefficients For Radionuclides Produced In A Spallation Neutron Source, John P. Shanahan, K. Eckerman, A. Arndt, C. Gold, Phillip W. Patton, Mark Rudin, R. Brey, T. Gesell, V. Rusetski, S. Pagava

Transmutation Sciences Physics (TRP)

Internal and external dose coefficient values have been calculated for 14 anthropogenic radionuclides which are not currently presented in Federal Guidance Reports Nos. 11, 12, and 13 or Publications 68 and 72 of the International Commission on Radiological Protection. Internal dose coefficient values are reported for inhalation and ingestion of 1 μm and 5 μm AMAD particulates along with the f₁ values and absorption types for the adult worker. Internal dose coefficient values are also reported for inhalation and ingestion of 1 μm AMAD particulates as well as the f₁ values and absorption types for members of the …

Nuclear Criticality, Shielding, And Thermal Analyses Of Separations Processes For The Transmutation Fuel Cycle, William Culbreth, Denis Beller

Separations Campaign (TRP)

The remediation of nuclear waste created by conventional fission reactors will rely upon the separation of the waste products for further treatment. The UREX+ process now under review will involve the use of an aqueous chemical process to separate out depleted uranium resulting in a product containing minor actinides, fission products, cesium, strontium, technetium, and iodine. The radioactive decay of strontium and cesium produces roughly half of the thermal and gamma production in spent fuel and the relatively short halflife of isotopes of both of these elements requires storage for about 300 years before heat and radiation decreases to safe …

Nuclear Criticality Analyses Of Separations Processes For The Transmutation Fuel Cycle, William Culbreth, Pang Tao, Denis Beller

Separations Campaign (TRP)

The separation and partitioning of used commercial reactor fuel is a vital component of any reprocessing or transmutation strategy. To process the high actinide fuels required for a transmutation effort, the Chemical Technology Division (CMT) at Argonne National Laboratory (ANL) is developing a pyrochemical separations process. Currently, this work is being done via small experiments. While this is more than sufficient to develop the technologies required to process actinide-bearing fuels, it does not allow for the direct investigation of criticality concerns that would be present in larger systems. As the volume of waste to be treated increases, a higher probability …

Inside Unlv, Diane Russell, Richard Jensen, Andy Grossman, Kevin Force

Inside UNLV

No abstract provided.

Dual -Enrolled Student Success In An Open Enrollment Community College, Frank James Dipuma

UNLV Retrospective Theses & Dissertations

The study investigated student success in a dual enrollment program at an open enrollment community college. The objective of the analysis was to determine the success of dual enrolled students compared with regularly enrolled community college students. Indicators of student success, including GPA, retention, and remediation, were examined for dual enrolled students; Results of the study indicated that high school students concurrently enrolled at a community college were similar in many respects to the general college population. Overall, there was a significant difference in the GPA performance between Community College High School (CCHS) students and regularly enrolled college students, with …

Traditional And Nontraditional Teacher Perceptions And Applications Of Dap, Connie Lynn Malin

UNLV Retrospective Theses & Dissertations

This study was conducted to ascertain the perceptions of developmentally appropriate practices in teachers trained through traditional teacher preparation programs and a nontraditional teacher preparation program conducted in a Professional Development School. The secondary purpose was to determine whether the teachers' perceptions were applied as instructional practices; In Phase One of the study, 60, first year teachers were asked to complete The Primary Teacher Questionnaire to determine their perceptions of developmental appropriateness. A total of 12 subjects were stratified, randomly selected to advance to Phase Two and were observed teaching a 60 minute literacy lesson for applications of developmentally appropriate …

A Phenomenological Study: Mid-Career Changer Transitions Through Levels Of Expertise, Merrie Lynne Schroeder

UNLV Retrospective Theses & Dissertations

The purpose of this phenomenological study was to understand how two midlife adult men experienced different levels of expertise as they transitioned between non-teaching and teaching professions. Of further interest were the unique qualities that these mid career changers brought to secondary education and their recommendations for improving preparation, induction, and retention of midlife career changers in teaching; The study examined the transition experiences through three dimensions: (1) the levels of creativity in the context of environments; (2) the physical, social, and emotional development of the individuals; and (3) the theoretical framework of expertise. Semistructured interviews were conducted, and analyses …

Assessing Faculty Perspectives On Implementing The Boyer Model, Delilah Anne Schwaner

UNLV Retrospective Theses & Dissertations

The Boyer model is a well-recognized format chosen by many universities as a guide for leave, rank and tenure criteria, and for rewarding activities by faculty. Given a past, brief association with this model by faculty and administration at Southern Utah University, and the continuing need for a comprehensive review of scholarly effort in the institution, this study was undertaken to gauge the level of understanding of Boyer's model and his four scholarships, satisfaction with present policies, and attitudes toward change. The aim was to explore the use of a questionnaire as an instrument to measure knowledge and attitudes, to …

Tadpole Shrimp (Triops Longicaudatus) Responses To Acute And Developmental Hypoxic Exposure, Stacey Lynn Harper

UNLV Retrospective Theses & Dissertations

Tadpole shrimp Triops longicaudatus (Crustacea: Branchiopoda: Notostraca) were reared under normoxic (19--21 kPa O2), moderate (10--13 kPa O2) or severe (1--3 kPa O2) hypoxic conditions to investigate the effects of developmental Po2 (partial pressure of oxygen) on adult metabolic, respiratory and cardiovascular physiology. Growth rates were independent of developmental Po2, although adult body size was significantly smaller in tadpole shrimp reared under severe hypoxic conditions relative to those reared under normoxic conditions. Most organisms increase respiratory surface area in response to hypoxic exposure. Yet growth of the epipodites (proposed respiratory structure) relative to mass (Y = aMb) was significantly reduced …

The Effects Of Socialization Through The Arts: Teaching Life Skills Strategies To Youth In West Las Vegas, Marcia Raquel Robinson

UNLV Retrospective Theses & Dissertations

There are at least 200 gangs in Southern Nevada with more than 7,700 identified members. "Gang bangers" do not anticipate a future or invest in "dreams," most do not expect to live beyond their 20's. Las Vegas is more the rule than the exception; the West Las Vegas community is the epicenter needing attention. The planning and development of this pilot program "The Performing and Visual Arts Camp for Kids" focused on teaching life skills and character development, such as getting along with others, respect for oneself and others, initiative, the ability to communicate, problem solving, perseverance, and goal setting …

A Framework For Secure Applications With Qos, Ajay Kanagala

UNLV Retrospective Theses & Dissertations

In this thesis we propose a solution to support Quality of Service (QoS) network communication transactions modeled on differentiated services and economic principles. We propose an enhanced user-level negotiation protocol where transactions are accomplished in a secure mode and where resource allocations are simple and fair. With the availability of inexpensive network monitoring hardware, any issue dealing with network security becomes a priority. Current networks must support multiple levels of service over a single network connection. Differentiated levels of service create new resource management problems for network middleware. Just as a first class passenger is willing to pay the premium …

Numerical Solutions To Poisson's Equation Using Radial Basis Functions, Michael David Ludian

UNLV Retrospective Theses & Dissertations

This thesis addresses the problem of obtaining solutions to Poisson's equation which is encountered in the applied sciences and engineering fields. Two separate methods are explained for obtaining particular solutions to this equation. The Method of Fundamental Solutions is then used to solve the remaining homogeneous equation in the context of the Method of Particular Solutions and Dual Reciprocity Method. Numerous examples are given using 2-D and 3-D domain problems; The first method is an interpolation method that has resulted in some problems with ill-conditioning of the matrix used in the problem solving and a remedy has been examined in …

Token Economy Used To Increase Performance In Solving Algebra Problems For High School Students, Kari Mankes Maes

UNLV Retrospective Theses & Dissertations

The purpose of this investigation was to evaluate the effects of using a token economy approach to increase the performance in solving algebra homework quizzes for two high school boys. The program included tokens that could be redeemed for candy or extra credit points to encourage the students to try harder to check over their answers on homework quizzes before handing them in to be graded. Permanent product was used to record the scores of the homework quizzes and a comparison of baseline data and intervention data was done with a reversal design. The results showed that the students did …

A Noise Detection, Noise-Motion Separation And A Cancer Recognition Theory And Algorithm, Alexander Popovich

UNLV Retrospective Theses & Dissertations

In this thesis we describe a noise detection and a motion-noise separation algorithm, as well as the stochastic properties of the noise. The difference between corresponding pixels subject to one type of noise, of two frames, has mean vector equal to (0,0,0), and variance covariance matrix with relatively small variances, for the (R, G, B) difference values. The other type of noise is a result of disturbance of the light equilibrium due to motion in neighboring or nearby pixels. In this type of noise the mean of the difference is non-zero. Every pixel not included in the one type of …

Negotiation And Autonomy In A Fast Food Restaurant, Eric Orion Silva

UNLV Retrospective Theses & Dissertations

This study is an attempt to apply the negotiated order perspective to the analysis of the lived experience of workers in two franchised fast food restaurants. Drawing primarily on the work of Anselm Strauss (1978) and D. H. J. Morgan (1975), I have examined data taken from auto-ethnographic and overt observation. I found that workers in different negotiation contexts would use implicit and explicit negotiation to achieve internal and external goals. Worker's negotiation strategies depended on the actor's individual proclivities and their interpretation of the negotiation context. Issues subject to negotiation included wages, the schedule, the amount of effort expended, …

The Asymptotic Behavior Of The Integer Solutions Of The Rosenberger Equations, Kensaku Umeda

UNLV Retrospective Theses & Dissertations

The Rosenberger equations are equations of the form: ax 2 + by2 + cz 2 = dxyz, where the sets of coefficients ( a, b, c, d) are all integers such that each of a, b, and c divides d, and the equations themselves have infinitely many integer solutions. Rosenberger has shown that there are only six such sets of coefficients, one of which is the Markoff equation, x2 + y2 + z2 = 3xyz. Zagier investigated the asymptotic behavior of the integer solutions of the Markoff equation. In this paper, we apply Zagier's techniques to the Rosenberger equations and …

From Equi-Graphical Sets To Graphical Permutations: A Problem Of Degrees In Graphs, Michael Lee Watson

UNLV Retrospective Theses & Dissertations

A set {a1, a2,.., an} of positive integers with a 1 < a2 < &cdots; < an is said to be equi-graphical if there exists a graph with exactly ai vertices of degree ai for each i with 1 ≤ i ≤ n. It is known that such a set is equi-graphical if and only if i=1nai is even and an≤i=1n-1 ai2 . This concept is now generalized to the following problem: Given a set S of positive integers and a permutation pi on S, determine when there exists a graph containing exactly ai vertices of degree pi(ai) for each i (1 ≤ i ≤ n). If such a graph exists, then pi is called a graphical permutation; In this paper, the graphical permutations on sets of size four are characterized and using a criterion of Fulkerson, Hoffman, and McAndrew, we show that a permutation pi of S = {a1, a2, .. , an}, where 1 ≤ a1 < a2 < &cdots; < an and such that pi(a n) = an, is graphical if and only if i=1naip ai is even and an≤i=1n-1 aipai .