Variational formulation of the Gardner's restacking algorithm (open access)

Variational formulation of the Gardner's restacking algorithm

The incompressibility of the phase flow of Hamiltonian wave-plasma interactions restrains the class of realizable wave-driven transformations of the particle distribution. After the interaction, the distribution remains composed of the original phase-space elements, or local densities, which are only rearranged (''restacked'') by the wave. A variational formalism is developed to study the corresponding limitations on the energy and momentum transfer. A case of particular interest is a toroidal plasma immersed in a dc magnetic field. The restacking algorithm by Gardner [Phys. Fluids 6, 839 (1963)] is formulated precisely. The minimum energy state for a plasma with a given current is determined
Date: April 26, 2004
Creator: Dodin, I. Y. & Fisch, N. J.
System: The UNT Digital Library
Chemical Technology Division Annual Report 2000. (open access)

Chemical Technology Division Annual Report 2000.

The Chemical Technology Division (CMT) is one of eight engineering research divisions within Argonne National Laboratory (ANL), one of the U.S. government's oldest and largest research laboratories. The University of Chicago oversees the laboratory on behalf of the U.S. Department of Energy (DOE). Argonne's mission is to conduct basic scientific research, to operate national scientific facilities, to enhance the nation's energy resources, and to develop better ways to manage environmental problems. Argonne has the further responsibility of strengthening the nation's technology base through developing industrial technology and transferring that technology to industry. The Chemical Technology Division is a diverse early-stage engineering organization, specializing in the treatment of spent nuclear fuel, development of advanced power sources, and management of both high- and low-level nuclear wastes. Although this work is often indistinguishable from basic research, our efforts are directed toward the practical devices and processes that are covered by ANL's mission. Additionally, the Division operates the Analytical Chemistry Laboratory, which provides a broad range of analytical services to ANL and other organizations. The Division is multi-disciplinary. Its people have formal training as ceramists; physicists; material scientists; electrical, mechanical, chemical, and nuclear engineers; and chemists. They have experience working in academia, urban planning, …
Date: April 26, 2001
Creator: Lewis, D.; Gay, E. C.; Miller, J. F.; Einziger, R. E. & Green, D. W.
System: The UNT Digital Library
Solid State Division Progress Report for Period Ending September 30, 1999 (open access)

Solid State Division Progress Report for Period Ending September 30, 1999

This report covers research progress in the Solid State Division from April 1, 1997, through September 30, 1999. During this period, the division conducted a broad, interdisciplinary materials research program in support of Department of Energy science and technology missions. The report includes brief summaries of research activities in condensed matter theory, neutron scattering, synthesis and characterization of materials, ion beam and laser processing, and the structure of solids and surfaces. An addendum includes listings of division publications and professional activities. Over the past two years, a number of important infrastructure improvements that will provide significant new research opportunities and unique capabilities for the division in neutron scattering and synchrotron x-ray research, electron microscopy, nanostructure fabrication, and theory have been pursued. A major upgrade of neutron scattering capabilities at the High Flux Isotope Reactor (HFIR), including a high-performance cold source, new beam lines and guides, and new and upgraded instrumentation, is under way. These upgrades, together with the proposed Spallation Neutron Source at ORNL, will provide the nation with unsurpassed capabilities worldwide in neutron scattering. The division is also involved in the development of two synchrotron beam lines at the Advanced Photon Source at Argonne National Laboratory, an upgrade of …
Date: February 26, 2001
Creator: Cooke, J.F.
System: The UNT Digital Library
Approximate Integrals of rf-driven Particle Motion in Magnetic Field (open access)

Approximate Integrals of rf-driven Particle Motion in Magnetic Field

For a particle moving in nonuniform magnetic field under the action of an rf wave, ponderomotive effects result from rf-driven oscillations nonlinearly coupled with Larmor rotation. Using Lagrangian and Hamiltonian formalism, we show how, despite this coupling, two independent integrals of the particle motion are approximately conserved. Those are the magnetic moment of free Larmor rotation and the quasi-energy of the guiding center motion parallel to the magnetic field. Under the assumption of non-resonant interaction of the particle with the rf field, these integrals represent adiabatic invariants of the particle motion.
Date: April 26, 2004
Creator: Dodin, I. Y. & Fisch, N. J.
System: The UNT Digital Library
Modeled Neutron Induced Nuclear Reaction Cross Sections for Radiochemistry in the region of Iriduim and Gold (open access)

Modeled Neutron Induced Nuclear Reaction Cross Sections for Radiochemistry in the region of Iriduim and Gold

We have developed a set of modeled nuclear reaction cross sections for use in radiochemical diagnostics. Systematics for the input parameters required by the Hauser-Feshbach statistical model were developed and used to calculate neutron induced nuclear reaction cross sections for targets ranging from osmium (Z = 76) to gold (Z = 79). Of particular interest are the cross sections on Ir and Au including reactions on isomeric targets.
Date: February 26, 2008
Creator: Hoffman, R. D.; Dietrich, F. S.; Kelley, K.; Escher, J.; Bauer, R. & Mustafa, M. G.
System: The UNT Digital Library
300 Area Uranium Leach and Adsorption Project (open access)

300 Area Uranium Leach and Adsorption Project

The objective of this study was to measure the leaching and adsorption characteristics of uranium in six near-surface sediment samples collected from the 300 Area of the Hanford Site. Scanning electron micrographs of the samples showed that the uranium contamination in the sediments is most likely present as co-precipitates and/or discrete uranium particles. Molecular probe techniques also confirm the presence of crystalline discrete uranium bearing phases. In all cases, the uranium is present as oxidized uranium (uranyl [U(VI)]). Results from the column leach tests showed that uranium leaching did not follow a constant solubility paradigm. Four of the five contaminated sediments showed a large near instantaneous release of a few percent of the total uranium followed by a slower continual release. Steady-state uranium leachate concentrations were never measured and leaching characteristics and trends were not consistent among the samples. Dissolution kinetics were slow, and the measured leach curves most likely represent a slow kinetically controlled desorption or dissolution paradigm. Batch adsorption experiments were performed to investigate the effect of pH and uranium and carbonate solution concentrations on uranium adsorption onto the uncontaminated sediment. Uranium adsorption Kd values ranged from 0 to > 100 ml/g depending on which solution parameter was …
Date: November 26, 2002
Creator: Serne, R. Jeffrey; Brown, Christopher F.; Schaef, Herbert T.; Pierce, Eric M.; Lindberg, Michael J.; Wang, Zheming et al.
System: The UNT Digital Library
FEASIBILITY ANALYSIS FOR INSTALLING A CIRCULATING FLUIDIZED BED BOILER FOR COFIRING MULTIPLE BIOFUELS AND OTHER WASTES WITH COAL AT PENN STATE UNIVERSITY (open access)

FEASIBILITY ANALYSIS FOR INSTALLING A CIRCULATING FLUIDIZED BED BOILER FOR COFIRING MULTIPLE BIOFUELS AND OTHER WASTES WITH COAL AT PENN STATE UNIVERSITY

The Pennsylvania State University, utilizing funds furnished by the U.S. Department of Energy's Biomass Power Program, investigated the installation of a state-of-the-art circulating fluidized bed boiler at Penn State's University Park campus for cofiring multiple biofuels and other wastes with coal, and developing a test program to evaluate cofiring biofuels and coal-based feedstocks. The study was performed using a team that included personnel from Penn State's Energy Institute, Office of Physical Plant, and College of Agricultural Sciences; Foster Wheeler Energy Services, Inc.; Foster Wheeler Energy Corporation; Parsons Energy and Chemicals Group, Inc.; and Cofiring Alternatives. The activities included assessing potential feedstocks at the University Park campus and surrounding region with an emphasis on biomass materials, collecting and analyzing potential feedstocks, assessing agglomeration, deposition, and corrosion tendencies, identifying the optimum location for the boiler system through an internal site selection process, performing a three circulating fluidized bed (CFB) boiler design and a 15-year boiler plant transition plan, determining the costs associated with installing the boiler system, developing a preliminary test program, determining the associated costs for the test program, and exploring potential emissions credits when using the biomass CFB boiler.
Date: March 26, 2003
Creator: Miller, Bruce G.; Miller, Sharon Falcone; Cooper, Robert; Gaudlip, John; Lapinsky, Matthew; McLaren, Rhett et al.
System: The UNT Digital Library
Development of Mercury and Hydrogen Chloride Emission Monitors for Coal Gasifiers (open access)

Development of Mercury and Hydrogen Chloride Emission Monitors for Coal Gasifiers

The gas conditioning issues involved with coal gasification streams are very complex and do not have simple solutions. This is particularly true in view of the fact that the gas conditioning system must deal with tars, high moisture contents, and problems with NH{sub 3} without affecting low ppb levels of Hg, low levels (low ppm or less) of HCl, or the successful operation of conditioner components and analytical systems. Those issues are far from trivial. Trying to develop a non-chemical system for gas conditioning was very ambitious in view of the difficult sampling environment and unique problems associated with coal gasification streams. Although a great deal was learned regarding calibration, sample transport, instrumentation options, gas stream conditioning, and CEM design options, some challenging issues still remain. Sample transport is one area that is often not adequately considered. Because of the gas stream composition and elevated temperatures involved, special attention will need to be given to the choice of materials for the sample line and other plumbing components. When using gas stream oxidation, there will be sample transport regions under oxidizing as well as reducing conditions, and each of those regions will require different materials of construction for sample transport. The …
Date: February 26, 2001
Creator: Norton, G.; Eckels, D. & Chriswell, C.
System: The UNT Digital Library
Studies of Correlated-Electron Systems in High Magnetic Fields and at High Pressures (open access)

Studies of Correlated-Electron Systems in High Magnetic Fields and at High Pressures

None
Date: March 26, 2008
Creator: Cornelius, Dr. Andrew
System: The UNT Digital Library
Navy-Marine Corps Amphibious and Maritime Prepositioning Ship Programs: Background and Oversight Issues for Congress (open access)

Navy-Marine Corps Amphibious and Maritime Prepositioning Ship Programs: Background and Oversight Issues for Congress

The Navy is proposing to maintain in coming years a Navy with 31 amphibious ships and an additional squadron of 14 Maritime Prepositioning Force (Future), or MPF(F), ships. The squadron is intended to implement a new concept called sea basing, under which forces would be staged at sea and used to conduct expeditionary operations ashore with little or no reliance on nearby land bases. Potential oversight issues for Congress include the amphibious-ship force-level goal, the potential affordability and cost-effectiveness of the sea basing concept, and Navy and Marine Corps coordination with other services in developing the concept.
Date: July 26, 2006
Creator: O'Rourke, Ronald
System: The UNT Digital Library
Navy-Marine Corps Amphibious and Maritime Prepositioning Ship Programs: Background and Oversight Issues for Congress (open access)

Navy-Marine Corps Amphibious and Maritime Prepositioning Ship Programs: Background and Oversight Issues for Congress

None
Date: July 26, 2006
Creator: O'Rourke, Ronald
System: The UNT Digital Library
Navy-Marine Corps Amphibious and Maritime Prepositioning Ship Programs: Background and Oversight Issues for Congress (open access)

Navy-Marine Corps Amphibious and Maritime Prepositioning Ship Programs: Background and Oversight Issues for Congress

None
Date: July 26, 2006
Creator: O'Rourke, Ronald
System: The UNT Digital Library
MAPPING FLOW LOCALIZATION PROCESSES IN DEFORMATION OF IRRADIATED REACTOR STRUCTURAL ALLOYS - FINAL REPORT. Nuclear Energy Research Initiative Program No. MSF99-0072. Period: August 1999 through September 2002. (ORNL/TM-2003/63) (open access)

MAPPING FLOW LOCALIZATION PROCESSES IN DEFORMATION OF IRRADIATED REACTOR STRUCTURAL ALLOYS - FINAL REPORT. Nuclear Energy Research Initiative Program No. MSF99-0072. Period: August 1999 through September 2002. (ORNL/TM-2003/63)

Metals that can sustain plastic deformation homogeneously throughout their bulk tend to be tough and malleable. Often, however, if a metal has been hardened it will no longer deform uniformly. Instead, the deformation occurs in narrow bands on a microscopic scale wherein stresses and strains become concentrated in localized zones. This strain localization degrades the mechanical properties of the metal by causing premature plastic instability failure or by inducing the formation of cracks. Irradiation with neutrons hardens a metal and makes it more prone to deformation by strain localization. Although this has been known since the earliest days of radiation damage studies, a full measure of the connection between neutron irradiation hardening and strain localization is wanting, particularly in commercial alloys used in the construction of nuclear reactors. Therefore, the goal of this project is to systematically map the extent of involvement of strain localization processes in plastic deformation of three reactor alloys that have been neutron irradiated. The deformation processes are to be identified and related to changes in the tensile properties of the alloys as functions of neutron fluence (dose) and degree of plastic strain. The intent is to define the role of strain localization in radiation embrittlement …
Date: September 26, 2003
Creator: Farrell, K.
System: The UNT Digital Library
[Navy-Marine Corps Amphibious and Maritime Prepositioning Ship Programs: Background and Oversight Issues for Congress, January 26, 2007] (open access)
Intelligent Monitoring System with High Temperature Distributed Fiberoptic Sensor for Power Plant Combustion Processes (open access)

Intelligent Monitoring System with High Temperature Distributed Fiberoptic Sensor for Power Plant Combustion Processes

The objective of the proposed work is to develop an intelligent distributed fiber optical sensor system for real-time monitoring of high temperature in a boiler furnace in power plants. Of particular interest is the estimation of spatial and temporal distributions of high temperatures within a boiler furnace, which will be essential in assessing and controlling the mechanisms that form and remove pollutants at the source, such as NOx. The basic approach in developing the proposed sensor system is three fold: (1) development of high temperature distributed fiber optical sensor capable of measuring temperatures greater than 2000 C degree with spatial resolution of less than 1 cm; (2) development of distributed parameter system (DPS) models to map the three-dimensional (3D) temperature distribution for the furnace; and (3) development of an intelligent monitoring system for real-time monitoring of the 3D boiler temperature distribution. Under Task 1, we have set up a dedicated high power, ultrafast laser system for fabricating in-fiber gratings in harsh environment optical fibers, successfully fabricated gratings in single crystal sapphire fibers by the high power laser system, and developed highly sensitive long period gratings (lpg) by electric arc. Under Task 2, relevant mathematical modeling studies of NOx formation in …
Date: September 26, 2006
Creator: Lee, Kwang Y.; Yin, Stuart S. & Boehman, Andre
System: The UNT Digital Library
Advanced Materials for PEM-Based Fuel Cell Systems (open access)

Advanced Materials for PEM-Based Fuel Cell Systems

Proton exchange membrane fuel cells (PEMFCs) are quickly becoming attractive alternative energy sources for transportation, stationary power, and small electronics due to the increasing cost and environmental hazards of traditional fossil fuels. Two main classes of PEMFCs include hydrogen/air or hydrogen/oxygen fuel cells and direct methanol fuel cells (DMFCs). The current benchmark membrane for both types of PEMFCs is Nafion, a perfluorinated sulfonated copolymer made by DuPont. Nafion copolymers exhibit good thermal and chemical stability, as well as very high proton conductivity under hydrated conditions at temperatures below 80 degrees C. However, application of these membranes is limited due to their high methanol permeability and loss of conductivity at high temperatures and low relative humidities. These deficiencies have led to the search for improved materials for proton exchange membranes. Potential PEMs should have good thermal, hydrolytic, and oxidative stability, high proton conductivity, selective permeability, and mechanical durability over long periods of time. Poly(arylene ether)s, polyimides, polybenzimidazoles, and polyphenylenes are among the most widely investigated candidates for PEMs. Poly(arylene ether)s are a promising class of proton exchange membranes due to their excellent thermal and chemical stability and high glass transition temperatures. High proton conductivity can be achieved through post-sulfonation of poly(arylene …
Date: October 26, 2005
Creator: McGrath, James E.; Baird, Donald G. & Spakovsky, Michael von
System: The UNT Digital Library
Advanced Materials for PEM-Based Fuel Cell Systems (open access)

Advanced Materials for PEM-Based Fuel Cell Systems

Proton exchange membrane fuel cells (PEMFCs) are quickly becoming attractive alternative energy sources for transportation, stationary power, and small electronics due to the increasing cost and environmental hazards of traditional fossil fuels. Two main classes of PEMFCs include hydrogen/air or hydrogen/oxygen fuel cells and direct methanol fuel cells (DMFCs). The current benchmark membrane for both types of PEMFCs is Nafion, a perfluorinated sulfonated copolymer made by DuPont. Nafion copolymers exhibit good thermal and chemical stability, as well as very high proton conductivity under hydrated conditions at temperatures below 80 °C. However, application of these membranes is limited due to their high methanol permeability and loss of conductivity at high temperatures and low relative humidities. These deficiencies have led to the search for improved materials for proton exchange membranes. Potential PEMs should have good thermal, hydrolytic, and oxidative stability, high proton conductivity, selective permeability, and mechanical durability over long periods of time. Poly(arylene ether)s, polyimides, polybenzimidazoles, and polyphenylenes are among the most widely investigated candidates for PEMs. Poly(arylene ether)s are a promising class of proton exchange membranes due to their excellent thermal and chemical stability and high glass transition temperatures. High proton conductivity can be achieved through post-sulfonation of poly(arylene ether) …
Date: October 26, 2005
Creator: McGrath, James E.
System: The UNT Digital Library
TANK 40 FINAL SB5 CHEMICAL CHARACTERIZATION RESULTS PRIOR TO NP ADDITION (open access)

TANK 40 FINAL SB5 CHEMICAL CHARACTERIZATION RESULTS PRIOR TO NP ADDITION

A sample of Sludge Batch 5 (SB5) was pulled from Tank 40 in order to obtain radionuclide inventory analyses necessary for compliance with the Waste Acceptance Product Specifications (WAPS). This sample was also analyzed for chemical composition including noble metals. Prior to radionuclide inventory analyses, a final sample of the H-canyon Np stream will be added to bound the Np addition anticipated for Tank 40. These analyses along with the WAPS radionuclide analyses will help define the composition of the sludge in Tank 40 that is currently being fed to DWPF as SB5. At the Savannah River National Laboratory (SRNL) the 3-L Tank 40 SB5 sample was transferred from the shipping container into a 4-L high density polyethylene vessel and solids allowed to settle overnight. Supernate was then siphoned off and circulated through the shipping container to complete the transfer of the sample. Following thorough mixing of the 3-L sample, a 239 g sub-sample was removed. This sub-sample was then utilized for all subsequent analytical samples. Eight separate aliquots of the slurry were digested, four with HNO{sub 3}/HCl (aqua regia) in sealed Teflon{reg_sign} vessels and four in Na{sub 2}O{sub 2} (alkali or peroxide fusion) using Zr crucibles. Due to the …
Date: February 26, 2009
Creator: Bannochie, C & Damon Click, D
System: The UNT Digital Library
ANALYSIS OF DUST DELIQUESCENCE FOR FEP SCREENING (open access)

ANALYSIS OF DUST DELIQUESCENCE FOR FEP SCREENING

The purpose of this report is to evaluate the potential for penetration of the Alloy 22 (UNS N06022) waste package outer barrier by localized corrosion due to the deliquescence of soluble constituents in dust present on waste package surfaces. The results support a recommendation to exclude deliquescence-induced localized corrosion (pitting or crevice corrosion) of the outer barrier from the total system performance assessment for the license application (TSPA-LA). Preparation of this report, and supporting laboratory studies and calculations, were performed as part of the planned effort in Work Package AEBM21, as implemented in ''Technical Work Plan for: Screening Evaluation for Dust Deliquescence and Localized Corrosion'' (BSC 2004 [DIRS 172804]), by Bechtel SAIC Company, LLC, and staff from three national laboratories: Sandia National Laboratories, Lawrence Livermore National Laboratory (LLNL), and Lawrence Berkeley National Laboratory (LBNL). The analysis and conclusions presented in this report are quality affecting, as determined in the controlling technical work plan. A summary of background information, based on work that was not performed under a quality assurance program, is provided as Appendix E. In this instance, the use of unqualified information is provided for transparency and corroboration only, and is clearly separated from uses of qualified information. Thus, …
Date: August 26, 2005
Creator: Bryan, C.
System: The UNT Digital Library
The distribution of an illustrated timeline wall chart and teacher's guide of 20th century physics (open access)

The distribution of an illustrated timeline wall chart and teacher's guide of 20th century physics

The American Physical Society's part of its centennial celebration in March of 1999 decided to develop a timeline wall chart on the history of 20th century physics. This resulted in eleven consecutive posters, which when mounted side by side, create a 23-foot mural. The timeline exhibits and describes the millstones of physics in images and words. The timeline functions as a chronology, a work of art, a permanent open textbook, and a gigantic photo album covering a hundred years in the life of the community of physicists and the existence of the American Physical Society. Each of the eleven posters begins with a brief essay that places a major scientific achievement of the decade in its historical context. Large portraits of the essays' subjects include youthful photographs of Marie Curie, Albert Einstein, and Richard Feynman among others, to help put a face on science. Below the essays, a total of over 130 individual discoveries and inventions, explained in dated text boxes with accompanying images, form the backbone of the timeline. For ease of comprehension, this wealth of material is organized into five color-coded story lines the stretch horizontally across the hundred years of the 20th century. The five story lines …
Date: December 26, 2000
Creator: Schwartz, Brian
System: The UNT Digital Library
INTELLIGENT MONITORING SYSTEM WITH HIGH TEMPERATURE DISTRIBUTED FIBEROPTIC SENSOR FOR POWER PLANT COMBUSTION PROCESSES (open access)

INTELLIGENT MONITORING SYSTEM WITH HIGH TEMPERATURE DISTRIBUTED FIBEROPTIC SENSOR FOR POWER PLANT COMBUSTION PROCESSES

The objective of the proposed work is to develop an intelligent distributed fiber optical sensor system for real-time monitoring of high temperature in a boiler furnace in power plants. Of particular interest is the estimation of spatial and temporal distributions of high temperatures within a boiler furnace, which will be essential in assessing and controlling the mechanisms that form and remove pollutants at the source, such as NOx. The basic approach in developing the proposed sensor system is three fold: (1) development of high temperature distributed fiber optical sensor capable of measuring temperatures greater than 2000 C degree with spatial resolution of less than 1 cm; (2) development of distributed parameter system (DPS) models to map the three-dimensional (3D) temperature distribution for the furnace; and (3) development of an intelligent monitoring system for real-time monitoring of the 3D boiler temperature distribution. Under Task 1, improvement was made on the performance of in-fiber grating fabricated in single crystal sapphire fibers, test was performed on the grating performance of single crystal sapphire fiber with new fabrication methods, and the fabricated grating was applied to high temperature sensor. Under Task 2, models obtained from 3-D modeling of the Demonstration Boiler were used to …
Date: December 26, 2004
Creator: Lee, Kwang Y.; Yin, Stuart S. & Boheman, Andre
System: The UNT Digital Library
Geotechnical, Hydrogeologic and Vegetation Data Package for 200-UW-1 Waste Site Engineered Surface Barrier Design (open access)

Geotechnical, Hydrogeologic and Vegetation Data Package for 200-UW-1 Waste Site Engineered Surface Barrier Design

Fluor Hanford (FH) is designing and assessing the performance of engineered barriers for final closure of 200-UW-1 waste sites. Engineered barriers must minimize the intrusion and water, plants and animals into the underlying waste to provide protection for human health and the environment. The Pacific Northwest National Laboratory (PNNL) developed Subsurface Transport Over Multiple Phases (STOMP) simulator is being used to optimize the performance of candidate barriers. Simulating barrier performance involves computation of mass and energy transfer within a soil-atmosphere-vegetation continuum and requires a variety of input parameters, some of which are more readily available than others. Required input includes parameter values for the geotechnical, physical, hydraulic, and thermal properties of the materials comprising the barrier and the structural fill on which it will be constructed as well as parameters to allow simulation of plant effects. This report provides a data package of the required parameters as well as the technical basis, rationale and methodology used to obtain the parameter values.
Date: November 26, 2007
Creator: Ward, Andy L.
System: The UNT Digital Library
D.C. Tuition Assistance Grants: Program May Increase College Choices, but a Few Program Procedures May Hinder Grant Receipt for Some Residents (open access)

D.C. Tuition Assistance Grants: Program May Increase College Choices, but a Few Program Procedures May Hinder Grant Receipt for Some Residents

A letter report issued by the General Accounting Office with an abstract that begins "Twenty-one percent of grant-eligible applicants who did not use the District of Columbia's tuition assistance grant (TAG) funding to attend a participating college or university may have encountered such barriers as college entrance requirements and the absence of minority outreach programs. Whether enrollment caps at colleges posed a barrier for applicants is unclear. In the program's first year, 516 of the nearly 2,500 eligible applicants did not use the grants. About 21 percent of the institutions in which applicants expressed interest restrict the number of out-of-state students that they will accept, although the extent to which this played a role in limiting access to these institutions is unclear. Enrollment at the University of the District of Columbia (UDC) changed little during the TAG program's first year. The TAG program and UDC appeared to serve different freshmen populations, which may account for the TAG program's minimal impact on UDC enrollment. Although concerns about TAG program administration were largely resolved with the revision of program regulations in December 2000, other administrative issues may hinder program operations, including the determination of applicant eligibility and the distribution of information on …
Date: December 26, 2001
Creator: United States. General Accounting Office.
System: The UNT Digital Library
Water Distribution and Removal Model (open access)

Water Distribution and Removal Model

The design of the Yucca Mountain high level radioactive waste repository depends on the performance of the engineered barrier system (EBS). To support the total system performance assessment (TSPA), the Engineered Barrier System Degradation, Flow, and Transport Process Model Report (EBS PMR) is developed to describe the thermal, mechanical, chemical, hydrological, biological, and radionuclide transport processes within the emplacement drifts, which includes the following major analysis/model reports (AMRs): (1) EBS Water Distribution and Removal (WD&R) Model; (2) EBS Physical and Chemical Environment (P&CE) Model; (3) EBS Radionuclide Transport (EBS RNT) Model; and (4) EBS Multiscale Thermohydrologic (TH) Model. Technical information, including data, analyses, models, software, and supporting documents will be provided to defend the applicability of these models for their intended purpose of evaluating the postclosure performance of the Yucca Mountain repository system. The WD&R model ARM is important to the site recommendation. Water distribution and removal represents one component of the overall EBS. Under some conditions, liquid water will seep into emplacement drifts through fractures in the host rock and move generally downward, potentially contacting waste packages. After waste packages are breached by corrosion, some of this seepage water will contact the waste, dissolve or suspend radionuclides, and ultimately …
Date: August 26, 2005
Creator: Deng, Yueying; Chipman, Veraun & Hardin, Ernest L.
System: The UNT Digital Library