4-D conformal field theories and strings on orbifolds (open access)

4-D conformal field theories and strings on orbifolds

None
Date: March 16, 1998
Creator: Kachru, Shamit & Silverstein, Eva
Object Type: Article
System: The UNT Digital Library
324 Building fire hazards analysis implementation plan (open access)

324 Building fire hazards analysis implementation plan

In March 1998, the 324 Building Fire Hazards Analysis (FHA) (Reference 1) was approved by the US Department of Energy, Richland Operations Office (DOE-RL) for implementation by B and W Hanford Company (BWHC). The purpose of the FHA was to identify gaps in compliance with DOE Order 5480.7A (Reference 2) and Richland Operations Office Implementation Directive (RLID) 5480.7 (Reference 3), especially in regard to loss limitation. The FHA identified compliance gaps in six areas and provided 20 recommendations to bring the 324 Building into compliance with DOE Order 5480.7A. Additionally, one observation was provided. To date, four of the recommendations and the one observation have been completed. Actions identified for seven of the recommendations are currently in progress. Exemption requests will be transmitted to DOE-RL for three of the recommendations. Six of the recommendations are related to future shut down activities of the facility and the corrective actions are not being addressed as part of this plan. The actions for recommendations associated with the safety related part of the 324 Building and operation of the cells and support areas were evaluated using the Unreviewed Safety Question (USQ) process. Major Life Safety Code concerns have been corrected. The status of the …
Date: September 16, 1998
Creator: Eggen, C.D.
Object Type: Report
System: The UNT Digital Library
327 Building fire hazards analysis implementation plan (open access)

327 Building fire hazards analysis implementation plan

In March 1998, the 327 Building Fire Hazards Analysis (FRA) (Reference 1) was approved by the US Department of Energy, Richland Operations Office (DOE-RL) for implementation by B and W Hanford Company (B and WHC). The purpose of the FHA was to identify gaps in compliance with DOE Order 5480.7A (Reference 2) and Richland Operations Office Implementation Directive (RLID) 5480.7 (Reference 3), especially in regard to loss limitation. The FHA identified compliance gaps in five areas and provided nine recommendations (11 items) to bring the 327 Building into compliance. To date, actions for five of the 11 items have been completed. Exemption requests will be transmitted to DOE-RL for two of the items. Corrective actions have been identified for the remaining four items. The completed actions address combustible loading requirements associated with the operation of the cells and support areas. The status of the recommendations and actions was confirmed during the July 1998 Fire Protection Assessment. B and WHC will use this Implementation Plan to bring the 327 Building and its operation into compliance with DOE Order 5480.7A and RLID 5480.7.
Date: September 16, 1998
Creator: Eggen, C.D.
Object Type: Report
System: The UNT Digital Library
Activity plan: Directional drilling and environmental measurements while drilling (open access)

Activity plan: Directional drilling and environmental measurements while drilling

This activity plan describes the testing of directional drilling combined with environmental measurements while drilling at two Hanford Site locations. A cold test is to be conducted at the 105A Mock Tank Leak Facility in the 200 East Area. A hot test is proposed to be run at the 216-B-8 tile field north of the 241-B Tank Farm in 200 East Area. Criteria to judge the success, partial success or failure of various aspects of the test are included. The TWRS program is assessing the potential for use of directional drilling because of an identified need to interrogate the vadose zone beneath the single-shell tanks. Because every precaution must be taken to assure that investigation activities do not violate the integrity of the tanks, control of the drill bit and ability to follow a predetermined drill path are of utmost importance and are being tested.
Date: July 16, 1998
Creator: Myers, D.A.
Object Type: Report
System: The UNT Digital Library
ADVANCED SORBENT DEVELOPMENT PROGRAM (open access)

ADVANCED SORBENT DEVELOPMENT PROGRAM

The overall objective of this program was to develop regenerable sorbents for use in the temperature range of 343 to 538 C (650 to 1000 F) to remove hydrogen sulfide (H{sub 2}S) from coal-derived fuel gases in a fluidized-bed reactor. The goal was to develop sorbents that are capable of reducing the H{sub 2}S level in the fuel gas to less than 20 ppmv in the specified temperature range and pressures in the range of 1 to 20 atmospheres, with chemical characteristics that permit cyclic regeneration over many cycles without a drastic loss of activity, as well as physical characteristics that are compatible with the fluidized bed application.
Date: June 16, 1998
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Advanced thermal barrier coating system development. Technical progress report (open access)

Advanced thermal barrier coating system development. Technical progress report

The objectives of the program are to provide an improved thermal barrier coating (TBC) system with increased temperature capability and improved reliability relative to current state of the art TBC systems. The development of such a coating system is essential to the Advanced Turbine Systems (ATS) engine meeting its objectives. The base program consists of three phases: Phase 1, Program Planning -- Complete; Phase 2, Development; Phase 3, Selected Specimen -- Bench Test. Work is being performed in Phase 2 and 3 of the program.
Date: June 16, 1998
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Advanced thermal barrier coating system development. Technical progress report (open access)

Advanced thermal barrier coating system development. Technical progress report

This report describes work to develop new thermal barrier coating systems, which will be essential to the operation of the ATS engine which is under development. Work is at the stage of process improvement and bond coat improvement, along with proof testing of the coatings under thermal conditions typical of what can be expected in the ATS engine.
Date: March 16, 1998
Creator: unknown
Object Type: Report
System: The UNT Digital Library
ALEGRA -- code validation: Experiments and simulations (open access)

ALEGRA -- code validation: Experiments and simulations

In this study, the authors are providing an experimental test bed for validating features of the ALEGRA code over a broad range of strain rates with overlapping diagnostics that encompass the multiple responses. A unique feature of the Arbitrary Lagrangian Eulerian Grid for Research Applications (ALEGRA) code is that it allows simultaneous computational treatment, within one code, of a wide range of strain-rates varying from hydrodynamic to structural conditions. This range encompasses strain rates characteristic of shock-wave propagation (10{sup 7}/s) and those characteristic of structural response (10{sup 2}/s). Most previous code validation experimental studies, however, have been restricted to simulating or investigating a single strain-rate regime. What is new and different in this investigation is that the authors have performed well-instrumented experiments which capture features relevant to both hydrodynamic and structural response in a single experiment. Aluminum was chosen for use in this study because it is a well characterized material--its EOS and constitutive material properties are well defined over a wide range of loading rates. The current experiments span strain rate regimes of over 10{sup 7}/s to less than 10{sup 2}/s in a single experiment. The input conditions are extremely well defined. Velocity interferometers are used to record the …
Date: March 16, 1998
Creator: Chhabildas, L. C.; Konrad, C. H.; Mosher, D. A.; Reinhart, W. D.; Duggins, B. D.; Rodeman, R. et al.
Object Type: Article
System: The UNT Digital Library
Alpha Contamination Levels in SMF South Cell and Compartments (open access)

Alpha Contamination Levels in SMF South Cell and Compartments

This document describes the detailed contamination survey performed in the Shielded Materials Facility (SMF) South Cell and the four compartments used during the CsCl activities. Smears were obtained at each operating station in South Cell and analyzed at the 325 Building. The smear results indicate that the highest contamination levels are in Compartment 1 and South Cell proper, with significantly lower contamination levels measured in the other three compartments. Although some of the smears indicated the presence of alpha contamination, it will be shown that the source of the alpha contamination was cross-contamination during processing in the 325 Building hot cells and that the SMF is free of alpha contamination. The alpha-free status of South Cell is consistent with process knowledge of previous South Cell activities.
Date: June 16, 1998
Creator: Durham, J. S.
Object Type: Report
System: The UNT Digital Library
An analysis of plutonium immobilization versus the "spent fuel" standard (open access)

An analysis of plutonium immobilization versus the "spent fuel" standard

Safe Pu management is an important and urgent task with profound environmental, national, and international security implications. Presidential Policy Directive 13 and analyses by scientific, technical, and international policy organizations brought about a focused effort within the Department of Energy (DOE) to identify and implement long-term disposition paths for surplus Pu. The principal goal is to render surplus Pu as inaccessible and unattractive for reuse in nuclear weapons as Pu in spent reactor fuel. In the Programmatic Environmental Impact Statement and Record of Decision for the Storage and Disposition of Weapons- Usable Fissile Materials (1997), DOE announced pursuit of two disposition technologies: (1) irradiation of Pu as MOX fuel in existing reactors and (2) immobilization of Pu into solid forms containing fission products as a radiation barrier. DOE chose an immobilization approach that includes �use of the can-in-canister option.. . for a portion of the surplus, non-pit Pu material.� In the can-in-canister approach, cans of glass or ceramic forms containing Pu are encapsulated within canisters of HLW glass. In support of the selection process, a technical evaluation of retrievability and recoverability of Pu from glass and ceramic forms by a host nation and by rogue nations or subnational groups was …
Date: June 16, 1998
Creator: Gray, W. L. & McKibben, J. M.
Object Type: Article
System: The UNT Digital Library
Analysis of the Rotopod: An all revolute parallel manipulator (open access)

Analysis of the Rotopod: An all revolute parallel manipulator

This paper introduces a new configuration of parallel manipulator call the Rotopod which is constructed from all revolute type joints. The Rotopod consists of two platforms connected by six legs and exhibits six Cartesian degrees of freedom. The Rotopod is initially compared with other all revolute joint parallel manipulators to show its similarities and differences. The inverse kinematics for this mechanism are developed and used to analyze the accessible workspace of the mechanism. Optimization is performed to determine the Rotopod design configurations which maximum the accessible workspace based on desirable functional constraints.
Date: May 16, 1998
Creator: Schmitt, D.J.; Benavides, G.L.; Bieg, L.F. & Kozlowski, D.M.
Object Type: Article
System: The UNT Digital Library
ARIES segmented gamma-ray scanner user manual (open access)

ARIES segmented gamma-ray scanner user manual

The segmented gamma-ray scatter (SGS) designated as Win{_}SGS at the Los Alamos Plutonium Facility has been installed and is intended for use in quantifying the radioisotope content of DOE-STD-3013-96 equivalent containers. The SGS features new software written in C and a new user interface that runs under Microsoft Windows{trademark}. The operation of the ARIES Segmented Gamma-ray Scanner is documented in this manual. It covers user instructions as well as hardware and software details. Additional information is found in the documentation for the commercially available components and modules that compose the SGS. The objective of the ARIES project is to demonstrate technology to dismantle plutonium pits from excess nuclear weapons, convert the plutonium to a metal ingot or an oxide powder, package the metal or oxide, and verify the contents of the package by nondestructive assay.
Date: April 16, 1998
Creator: Biddle, R. S.; Sheppard, G. A. & Schneider, C. M.
Object Type: Report
System: The UNT Digital Library
Assembly and maintenance of full scale NIF amplifiers in the amplifier module prototype laboratory (AMPLAB) (open access)

Assembly and maintenance of full scale NIF amplifiers in the amplifier module prototype laboratory (AMPLAB)

Mechanical assembly and maintenance of the prototype National Ignition Facility amplifiers in the Amplifier Module Prototype Laboratory (AMPLAB) at Lawrence Livermore National Laboratory requires specialized equipment designed to manipulate large and delicate amplifier components in a safe and clean manner. Observations made during the operation of this assembly and maintenance equipment in AMPLAB provide design guidance for similar tools being built for the National Ignition Facility. Fixtures used for amplifier frame installation, laser slab and flashlamp cassette assembly, transport, and installation, and in-situ blastshield exchange are presented. Examples include a vacuum slab gripper, slab handling clean crane, slab cassette assembly fixture, sealed transport vehicle for slab cassette movement between the cleanroom and amplifier, slab cassette transfer fixture between the cleanroom and transport vehicle, and equipment needed for frame assembly unit, blastshield, an d flashlamp cassette installation and removal. The use of these tools for amplifier assembly, system reconfiguration, reflector replacement, and recovery from an abnormal occurrence such as a flashlamp explosion is described. Observations are made on the design and operation of these tools and their contribution to the final design.
Date: July 16, 1998
Creator: Horvath, J. A.
Object Type: Article
System: The UNT Digital Library
Atmospheric chemistry effects of the 1998 Mexican/Central American fires measured in central New Mexico USA. (open access)

Atmospheric chemistry effects of the 1998 Mexican/Central American fires measured in central New Mexico USA.

Atmospheric effects from large fires have received a great deal of interest recently, especially when the fires have the potential to effect human health when the plumes are transported long distances over areas of high population density. Examples are the recent large fires in Southeast Asia in 1997 (1) and the wildfires occurring in southern Mexico and Central America that were manifested in decreased visibility and high aerosol concentrations in the United States at distances of 2500-4000 km from the fires. In addition to fine aerosols, these biomass fires have the potential to produce and transport large quantities of oxygenated organic species such as aldehydes, ketones and carboxylic acids, hydrocarbons, and sulfate and nitrate species. Most of the literature reports dealing with products of biomass burning have been related to fireplace and wood burning stove emissions (2,3) and with local effects from forest fires(4). The recent super-large fires occurring in Indonesia and Mexico/Central America also bring about the issue of atmospheric reactivity because long-range transport affords long reaction times for photochemical reactions, wet and dry deposition and surface reactions on the aerosol particles. The smoke/haze conditions prompted considerable concern among the general population in New Mexico regarding health hazards and …
Date: December 16, 1998
Creator: Popp, C. J.
Object Type: Article
System: The UNT Digital Library
Atomic site-specific theory of H on {gamma}U surface (open access)

Atomic site-specific theory of H on {gamma}U surface

This effort is a fundamental study of local chemical, electronic and physical behavior of metal and metal oxides as exposed to corrosive gases such as hydrogen and water vapor. The study benefits from state-of-art surface science experimental tools, such as scanning tunneling and atomic force microscopies (STM/AFM), photoelectron emission microscopy (PEEM), temperature programmed desorption (TPD) and modulated molecular beam mass spectrometry (MMBMS), to provide detailed knowledge of how, why and where a chemical reaction initiates and subsequently progresses with time, and theoretical/computational methods at the atomistic scale. The theoretical/computational component reported here consists of the first-principles calculation of the electronic structure of U surfaces exposed to H attack The calculations were designed to shed light on the energetic of various configurations of H interstitial impurities on the surface or in the substrate of U bcc metal. Predictions as to the preference of H to occupy surface or substrate interstitial positions can be made on the basis of the configuration with the lowest ground-state total energy.
Date: January 16, 1998
Creator: Gonis, A.
Object Type: Report
System: The UNT Digital Library
Bigplate: an oblique angle explosive EOS test (open access)

Bigplate: an oblique angle explosive EOS test

Bigplate is an advanced explosive equation of state (EOS) test. It consists of a point detonator driving a large disc (100 mm radius) of explosive, which pushes a 0.5 mm thick copper or tantalum plate. The plate is observed by a five-beam Fabry-Perot interferometer, which has beams at 0, 10, 20,40 and 80 mm on the plate. A short Fabry gives the jump-off to high accuracy; a long Fabry runs out to I0-15 microsec. A detailed error analysis is given, with the final velocity measurements considered good to ±0.066 mm/microsec. Jump-offs are measured to 0.01-0.02 microsec. Spall is seen in all shots, which creates a time delay on both the first and second velocity plateaus. A 0.1 microsec delay in jump-off of unknown origin is also seen at 80 mm. In order of decreasing explosive ideality, the explosives tired have been LX-14, LX-04 and LX-17. To partially negate the time delays, the data and code runs are overlaid at each radial position between the first and second plateaus. Traditional JWL's model LX-14 and LX-04 within accuracy, but not so for LX-17. The spall may be partly modeled using the pmin model but high resolution zoning is required. At longer times, …
Date: April 16, 1998
Creator: Anderson, S; Avara, R; Fried, L; Janzen, J; McGuire, E; Souers, P C et al.
Object Type: Report
System: The UNT Digital Library
Bremsstrahlung pair-production of positrons with low neutron background. (open access)

Bremsstrahlung pair-production of positrons with low neutron background.

Minimization of component activation is highly desirable at accelerator-based positron sources. Electrons in the 8- to 14-MeV energy range impinging on a target produce photons energetic enough to create electron-positron pairs; however, few of the photons are energetic enough to produce photoneutrons. Slow positron production by low-energy electrons impinging on a multilayer tungsten target with and without electromagnetic extraction between the layers was studied by simulation. The neutron background from 14-MeV electrons is expected to be significantly lower than that encountered with higher-energy electron beams. Numerical results are presented and some ideas for a low-activation slow-positron source are discussed.
Date: September 16, 1998
Creator: Lessner, E.
Object Type: Article
System: The UNT Digital Library
CDF forward shielding for Run II (open access)

CDF forward shielding for Run II

Detailed calculations of the accelerator related background in the CDF forward muon spectrometer have been performed with the MARS13 code and a newly developed C++ code for particle tracking in accelerator lattices. Calculated space distributions of background hits are in a good agreement with data taken in Run I. Several shielding configurations in the CDF hall and Tevatron tunnel have been studied. The optimal one provides a 30-fold shielding efficiency compatible with CDF Run II requirements.
Date: March 16, 1998
Creator: Krivosheev, O. E. & Mokhov, N. V.
Object Type: Report
System: The UNT Digital Library
CNEA/ANL collaboration program to develop an optimized version of DART validation and assessment by means of U{sub 3}Si{sub x} and U{sub 3}O{sub 8-}Al dispersed CNEA miniplate irradiation behavior. (open access)

CNEA/ANL collaboration program to develop an optimized version of DART validation and assessment by means of U{sub 3}Si{sub x} and U{sub 3}O{sub 8-}Al dispersed CNEA miniplate irradiation behavior.

The DART code is based upon a thermomechanical model that can predict swelling, recrystallization, fuel-meat interdiffusion and other issues related with MTR dispersed FE behavior under irradiation. As a part of a common effort to develop an optimized version of DART, a comparison between DART predictions and CNEA miniplates irradiation experimental data was made. The irradiation took place during 1981-82 for U3O8 miniplates and 1985-86 for U{sub 3}Si{sub x} at Oak Ridge Research Reactor (ORR). The microphotographs were studied by means of IMAWIN 3.0 Image Analysis Code and different fission gas bubbles distributions were obtained. Also it was possible to find and identify different morphologic zones. In both kinds of fuels, different phases were recognized, like particle peripheral zones with evidence of Al-U reaction, internal recrystallized zones and bubbles. A very good agreement between code prediction and irradiation results was found. The few discrepancies are due to local, fabrication and irradiation uncertainties, as the presence of U{sub 3}Si phase in U{sub 3}Si{sub 2} particles and effective burnup.
Date: October 16, 1998
Creator: Solis, D.
Object Type: Article
System: The UNT Digital Library
Coherent multimoded dielectric wakefield accelerators. (open access)

Coherent multimoded dielectric wakefield accelerators.

There has recently been a study of the potential uses of multimode dielectric structures for wakefield acceleration [1]. This technique is based on adjusting the wakefield modes of the structure to constructively interfere at certain delays with respect to the drive bunch, thus providing an accelerating gradient enhancement over single mode devices. In this report we examine and attempt to clarify the issues raised by this work in the light of the present state of the art in wakefield acceleration.
Date: July 16, 1998
Creator: Power, J.
Object Type: Article
System: The UNT Digital Library
A comparison of the RELAP5/MOD3 and PARET/ANL codes with the experimental transient data from the SPERT-IV D-12/25 series. (open access)

A comparison of the RELAP5/MOD3 and PARET/ANL codes with the experimental transient data from the SPERT-IV D-12/25 series.

The results from the RELAP5/MOD3 and PARET/ANL codes are compared with the SPERT-IV series of experimental reactivity insertion transients. The PARET/ANL code provides conservative estimates of SPERT-IV experimental data for the midrange transients and for the more severe transients. The PARET results are similar to the results obtained earlier for the SPERT-I D-12/25 series of experiments. The RELAP5/MOD3 code (including the developmental version 3.2.1.2) gives results comparable to PARET for some midrange transients, but seriously diverges from the experimental data when significant boiling is present. Based on the results of this study, the use of the RELAP5 code for research reactor applications should be limited to transients that do not generate substantial boiling and voids. We hope to be able to resolve these differences in further work with the NRC staff and its contractors. The RELAP5 code would be a more useful tool for the analyses research reactor transients with the addition of suitable correlations for low pressures and plate type geometry.
Date: January 16, 1998
Creator: Woodruff, W. L.
Object Type: Article
System: The UNT Digital Library
Design of a high charge (10 - 100 nC) and short pulse (2 - 5 ps) rf photocathode gun for wakefield acceleration. (open access)

Design of a high charge (10 - 100 nC) and short pulse (2 - 5 ps) rf photocathode gun for wakefield acceleration.

In this paper we present a design report on a 1-1/2 cell, L Band RF photocathode gun that is capable of generating and accelerating electron beams with peak currents >10 kA. We have performed simulation for bunch intensities in the range of 10-100 nC with peak axial electrical field at the photocathode of 30-100 MV/m. Unlike conventional short electron pulse generation, this design does not require magnetic pulse compression. Based on numerical simulations using SUPERFISH and PARMELA, this design will produce 20-100 nC beam at 18 MeV with rms bunch length 0.6-1.25 mm and normalized transverse emittance 30-108 mm mrad. Applications of this beam for wakefield acceleration is also discussed.
Date: July 16, 1998
Creator: Gai, W.
Object Type: Article
System: The UNT Digital Library
Develop the dual fuel conversion system for high output, medium speed diesel engines. Final report (open access)

Develop the dual fuel conversion system for high output, medium speed diesel engines. Final report

The original plan for the project involved design modifications to an existing system to enhance its performance and increase the limit of power that was achieved by the original design and to apply the higher performance product to the full sized engine and test its performance. The new system would also be applied to a different engine model. The specific work would include the redesign of gas injectors, piston configurations and two types of igniters, engine instrumentation, monitoring and testing.
Date: July 16, 1998
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Dose measurements of bremsstrahlung-produced neutrons from thick targets at the Advanced Photon Source. (open access)

Dose measurements of bremsstrahlung-produced neutrons from thick targets at the Advanced Photon Source.

Bremsstrahlung is produced in the Advanced Photon Source storage ring when the positron beam interacts with the storage-ring components or with the residual gas molecules in the storage-ring vacuum. This bremsstrahlung has an energy range of zero to 7.0 GeV, which is the maximum energy of the positron beam. Bremsstrahlung photons of sufficient high energy can interact with beamline components such as beam stops and collimators, generating neutrons of varying energies. This paper presents the results of simultaneous measurements, conducted at the Advanced Photon Source, of bremsstrahlung and the corresponding photoneutron production from thick targets of iron, copper, tungsten and lead, which allow one to correlate photoneutron dose rates from these metals as a function of bremsstrahlung power. The average photoneutron dose equivalent rates, normalized to the bremsstrahlung power, are measured as 2.7 {+-} 0.5 rem/h/W for iron, 3.2 {+-} 0.5 rem/h/W for copper, 3.9 {+-} 0.5 rem/h/W for tungsten, and 4.6 {+-} 0.8 rem/h/W for lead targets. These are measured at 80 cm lateral from the center of the targets, perpendicular to the photon beam direction.
Date: September 16, 1998
Creator: Job, P. K.
Object Type: Article
System: The UNT Digital Library