Physical Sciences and Mathematics Commons^™

Variability And Continuity Between Paleoindian Assemblages In The Northeast: A Technological Approach, Edward Cyrus Moore

Electronic Theses and Dissertations

The Paleoindian record in Maine consists almost exclusively of stone artifacts. Of these artifacts, the fluted projectile point is the most widely recognized and researched, particularly its morphology. Very little is known of the technological strategies involved in the production of Paleoindian stone tools or whether these strategies were consistent between Paleoindian sites. This research examines stone tool production methods and technological organization between two Paleoindian sites in Maine (Janet Cormier and Nicholas) using remnant technological attributes observed on discarded artifacts. Both sites are located in southwestern Maine within the Little Androscoggin River. The sites are situated on elevated, well-drained …

Mechanical Response Of Nets Of Graphical Objects, Rakesh Kumar Bajaj

Masters Theses

"This research produces networks of graphical objects that respond to human manipulation in a fashion that would be deemed physically reasonable. That is, a graphical network is given a mechanics-like behavior in the presence of the human interaction. In this approach, nonlinear models replace commonly used linear models to mimic physical reality better. Software solutions are provided via a class library useful for such interactive visual modeling"--Abstract, page iii.

Exploring Visitor Experiences On Going-To-The-Sun Road In Glacier National Park, Robert N. Giordano

Graduate Student Theses, Dissertations, & Professional Papers

Going-to-the-Sun Road (GTSR) is one of the premier road facilities in the world. As the only cross-mountain route through Glacier National Park, the road brings nearly two million visitors a year into the heart of Montana wilderness. How to meet this demand for travel while protecting the nature of the visitor experience and the pristine setting for which the experience exists is a challenge of on-going complexity.

This research was designed to assist park managers in determining future changes to GTSR by describing and analyzing the experiences on the road today. Through 40 onsite interviews at Logan Pass (the pinnacle …

The Role Of Diet And Physical Activity For Ovarian Cancer Results From The Adventist Health Study, Fatemeh Kiani

Loma Linda University Electronic Theses, Dissertations & Projects

A few aspects of the epidemiology of ovarian cancer are well understood, such as the inverse relationship with parity and oral contraceptive (OC) use. The role of other factors such as the potential influence of diet or physical activity is far from being established. A few studies, however, have been able to identify dietary risk factors for ovarian cancer. In this dissertation, I have conducted two studies that investigate the relationship between dietary factors and physical activity and the three endpoints: 1) nonfatal ovarian cancer (1976-1982; time to diagnosis), 2) fatal ovarian cancer (1976-1988; time to death), and 3) total …

Exploring The Limits Of The Dipole Approximation With Angle-Resolved Electron Time-Of-Flight Spectrometry, Sierra Laidman, Monica Pangilinan, Renaud Guillemin, Sung Woo Yu, Gunnar Ohrwall, Dennis W. Lindle, Oliver Hemmers

Environmental Studies Faculty Publications

Understanding the electronic structure of atoms and molecules is fundamental in determining their basic properties as well as the interactions that occur with different particles such as light. One such interaction is single photoionization; a process in which a photon collides with an atom or molecule and an electron with a certain kinetic energy is emitted, leaving behind a residual ion. Theoretical models of electronic structures use the dipole approximation to simplify x-ray interactions by assuming that the electromagnetic field of the radiation, expressed as a Taylor-series expansion, can be simplified by using only the first term. It has been …

Southern Nevada Interagency Science & Research Program, Public Lands Institute

Interagency Science and Research Strategy

Conduct and support high quality, relevant, up-to-date research that is needed to solve problems and make effective decisions to enhance conservation, restoration, and adaptive management of public lands.

Project Continuation Proposal: Radiation Transport Modeling Of Beam-Target Experiments For The Aaa Project, William Culbreth

Reactor Campaign (TRP)

The AAA program will rely on the use of an accelerator-based transmuter1 to expose spent nuclear fuel to high-energy neutrons. The neutron flux will be sufficient to activate or fission the long-lived isotopes of Tc, I, Pu, Am, Cm, and Np that present a significant radiological hazard in commercial spent fuel. Transmuter fuel will be subcritical and a high-energy proton accelerator is needed to maintain the necessary neutron flux through the use of a neutron spallation target. The maximum neutron energy produced by spallation (~ 800 MeV) is significantly higher than that produced by a commercial light water reactor (~ …

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 …

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.

Bonytail (Gila Elegans) May Enhance Survival Of Razorback Suckers (Xyrauchen Texanus) In Rearing Ponds By Preying On Exotic Crayfish, Nathan Lenon, Krystyna Anne Stave, Tom Burke, James E. Deacon

Public Policy and Leadership Faculty Publications

This study examined the potential of bonytail (Gila elegans) to enhance survival of young razorback sucker (Xyrauchen texanus) in rearing ponds by serving as a biological control agent for young stages of Red Swamp Crayfish (Procambarus clarki). Large populations of crayfish in rearing ponds negatively affect the survival of razorback suckers, through predation and competition for food. Traps made with 6.34 mm (0.25 inch) mesh have been used in an effort to reduce crayfish populations, however crayfish less than 17 mm carapace length (CPL) are able to escape. Juvenile bonytail in experimental trials ate young crayfish ranging in size from …

Design And Analysis Of A Process For Melt Casting Metallic Fuel Pins Incorporating Volatile Actinides, Yitung Chen, Darrell Pepper, Randy Clarksean

Fuels Campaign (TRP)

The Transmutation Research Program requires the incorporation of non-fertile actinides into the fuel matrix for the transmuter blanket. One of three currently proposed candidate matrices for the transmuter blanket is a metallic alloy fuel matrix. Metallic fuels are an outstanding candidate for a transmutation fuel due to excellent irradiation performance and ease of fabrication. However, including a volatile constituent during fabrication of these fuel pins presents a challenge. High vapor pressure actinides, particularly americium, are susceptible to rapid vaporization and transport using traditional metal fuel casting processes. As a result, only a fraction of the desired charge is incorporated into …