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7,052 Matching Results
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Rf breakdown studies in a SLAC disk-loaded structure
Rf breakdown studies in an S-band standing-wave disk-loaded accelerator structure have been completed. An equivalent traveling-wave accelerating gradient as high as 147 MV/m and a peak field in excess of 300 MV/m have been obtained. At these high gradients, considerable amounts of field emission and x-ray radiation are observed. Some of the field-emitted electrons are captured and focused by the rf fields and can be extracted on the axis of the structure. Their current, energy distribution and the x-ray radiation they produce are given. Rf processing as measured by the frequency of breakdown and the reduction in field emitted electron currents inside the structure can be speeded up considerably by the presence of argon. Some conjectures on the causes of breakdown are presented.
Date:
April 1, 1986
Creator:
Wang, J.W.; Nguyen-Tuong, V. & Loew, G.A.
System:
The UNT Digital Library
Imaging system for obtaining space- and time-resolved plasma images on TMX
A Reticon 50 x 50 photodiode array camera has been placed on Livermore's Tandem Mirror Experiment to view a 56-cm diameter plasma source of visible, vacuum-ultraviolet, and x-ray photons. The compact camera views the source through a pinhole, filters, a fiber optic coupler, a microchannel plate intensifier (MCPI), and a reducer. The images are digitized (at 3.3 MHz) and stored in a large, high-speed memory that has a capacity of 45 images. A local LSI-11 microprocessor provides immediate processing and display of the data. The data are also stored on floppy disks that can be further processed on the large Livermore Computer System. The temporal resolution is limited by the fastest MCPI gate. The number of images recorded is determined by the read-out time of the Reticon camera (minimum 0.9 msec). The spatial resolution of approximately 1.4 cm is fixed by the geometry and the pinhole of 0.025 cm. Typical high-quality color representation of some plasma images are included.
Date:
April 8, 1980
Creator:
Koehler, H.A. & Frerking, C.E.
System:
The UNT Digital Library
Electromagnetic ''Particle-in-Cell'' Plasma Simulation
''PIC'' simulation tracks particles through electromagnetic fields calculated self-consistently from the charge and current densities of the particles themselves, external sources, and boundaries. Already used extensively in plasma physics, such simulations have become useful in the design of accelerators and their r.f. sources. 5 refs.
Date:
April 22, 1985
Creator:
Langdon, A. B.
System:
The UNT Digital Library
Some effects of the transverse-stability requirement on the design of a grating linac
The transverse stability of the grating linac proposed by Palmer is analyzed. It is shown that an open structure such as a grating is always unstable transversely as long as it is uniform. The structure can be made stable by utilizing the strong focusing principle. This is achieved by periodically interrupting the grating shape. We analyze the strong focusing grating linac, and find that the stability requirement places a non-trivial constraint on the phase acceptance of the system.
Date:
April 1, 1982
Creator:
Kim, K. J. & Kroll, N. M.
System:
The UNT Digital Library
In-sodium creep behavior of alloys M-813 and Nimonic PE16
The in-sodium biaxial creep deformation of internally pressurized tube specimens of alloys M-813 and Nimonic PE16 was measured at 650/sup 0/C under constant stress conditions after 4000 hours of sodium exposure. Each alloy had specimens at two different stress levels, viz., 0 and 165 MPa (24,000 psi). The data showed negative diameter changes at zero stress, which were attributed to material densification associated with precipitation. Although material densification was also seen in comparable in-argon experiments, the in-sodium creep strains at 165 MPa and 650/sup 0/C were much lower than the corresponding in-argon values. The higher creep strains in argon are explained on the basis of two parallel mechanisms involving oxygen, which is present at a low level in sodium (1 ppM) as compared with approximately 1000 ppM in the argon environment. The trends in the current data are consistent with observations by earlier authors. Sodium exposure of Nimonic PE16 also resulted in 4 ..mu..m deep intergranular penetration, which did not have any apparent effect on its biaxial creep behavior.
Date:
April 1, 1980
Creator:
Anantatmula, R.P. & Gilbert, E.R.
System:
The UNT Digital Library
Thermal energy storage for cogeneration applications
Cogeneration is playing an increasingly important role in providing energy efficient power generation and thermal energy for space heating and industrial process heat applications. However, the range of applications for cogeneration could be further increased if the generation of electricity could be coupled from the generation of process heat. Thermal energy storage (TES) can decouple power generation from the production of process heat, allowing the production of dispatchable power while fully utilizing the thermal energy available from the prime mover. The Pacific Northwest Laboratory (PNL) leads the US Department of Energy's Thermal Energy Storage Program. The program focuses on developing TES for daily cycling (diurnal storage), annual cycling (seasonal storage), and utility applications (utility thermal energy storage (UTES)). Several of these technologies can be used in a cogeneration facility. This paper discusses TES concepts relevant to cogeneration and describes the current status of these TES systems.
Date:
April 1, 1992
Creator:
Drost, M.K. & Antoniak, Z.I.
System:
The UNT Digital Library
Dynamic positron emission tomography in man using small bismuth germanate crystals
Primary considerations for the design of positron emission tomographs for medical studies in humans are the need for high imaging sensitivity, whole organ coverage, good spatial resolution, high maximum data rates, adequate spatial sampling with minimum mechanical motion, shielding against out of plane activity, pulse height discrimination against scattered photons, and timing discrimination against accidental coincidences. We discuss the choice of detectors, sampling motion, shielding, and electronics to meet these objectives.
Date:
April 1, 1982
Creator:
Derenzo, S.E.; Budinger, T.F.; Huesman, R.H. & Cahoon, J.L.
System:
The UNT Digital Library
Compression planning for continuous improvement in quality programs
This paper describes an innovative approach to planning and prioritizing. The approach, Compression Planning,'' conserves time for the planners while building commitment to continuous improvement and implementation of the plan. Beginning May 1990, Compression Planning'' was applied to the first organization-wide effort at training integration for regulatory compliance at Battelle Pacific Northwest laboratory (PNL), a multi-program national laboratory. Various applications of this methodology have been used at PNL for programs since then.
Date:
April 1, 1992
Creator:
Willis, Y.A. (Willis Consulting, PA (United States)) & Hood, F.C. (Pacific Northwest Lab., Richland, WA (United States))
System:
The UNT Digital Library
Non-stoichiometric defects in YBaCuO thin films
Defects in superconducting YBaCuO thin films deposited by laser ablation are investigated by high resolution transmission electron microscopy. Micrographs reveal numerous defects in the YBaCuO film, falling into four basic classes. One of these is an interesting, non-stoichiometric helical defect structure which possibly corresponds to a growth-related screw dislocation. In general, defects in the YBaCuO film are associated both with growth geometry and with local deviations in stoichiometry. Substrate surface geometry is seen to have a profound effect on the number and type of defects produced. Simulation of annealing transformations using a static lattice, three dimensional, Monte Carlo technique is carried out to gain further insight into specific defect formation mechanisms. The results of these studies suggest preparation conditions that are expected to lead to films with improved critical current densities. 17 refs., 6 figs.
Date:
April 1, 1991
Creator:
Fendorf, M.; Tidjani, M.; Burmester, C.; Gronsky, R. (Lawrence Berkeley Lab., CA (United States)) & Wille, L. (Florida Atlantic Univ., Boca Raton, FL (United States). Dept. of Physics)
System:
The UNT Digital Library
Graphics-based site information management at Hanford TRU burial grounds
The objective of the project described in this paper is to demonstrate the use of integrated computer graphics and database techniques in managing nuclear waste facilities. The graphics-based site information management system (SIMS) combines a three- dimensional graphic model of the facility with databases which describe the facility's components and waste inventory. The SIMS can create graphic visualization of any site data. The SIMS described here is being used by Westinghouse Hanford Company (WHC) as part of its transuranic (TRU) waste retrieval program at the Hanford Reservation. It is being used to manage an inventory of over 38,000 containers, to validate records, and to help visualize conceptual designs of waste retrieval operations.
Date:
April 1, 1992
Creator:
Rod, S.R. (Pacific Northwest Lab., Washington, DC (United States))
System:
The UNT Digital Library
Development of high current and high brightness negative hydrogen ion sources
Negative hydrogen ions have found important applications in particle accelerators and in fusion research. These ions can be generated from two different types of ion sources---the surface conversion source and the volume production source. Recent experiments demonstrate that H/sup /minus// current exceeding 1 A can be obtained from both types of ion sources. Because of the lower H/sup /minus// ion temperature and the fact that they can be operated without cesium, volume H/sup /minus// sources are highly desired. However, further technology must be developed on the control of electrons and the reduction of gas flow before this type of sources become practical units of a multiampere neutral beam injection system.
Date:
April 1, 1988
Creator:
Leung, K. N.
System:
The UNT Digital Library
Measurements and evaluations of nuclear data to support early design needs of the FMIT facility
The Fusion Materials Irradiation Test (FMIT) facility is currently being designed for use in the study of neutron radiation effects in fusion reactor materials. This facility will make use of the intense source of high energy neutrons produced by a beam of 35 MeV deuterons incident upon a thick target of liquid lithium. In the forward direction, the neutron spectrum from this source peaks near 14 MeV as in a fusion device. However, the neutron energy spectrum in the FMIT facility will be broader and there will be a significant number of neutrons emitted with energies up to about 30 MeV. A small fraction will be emitted with even higher energies, up to a maximum of 50 MeV. Since ENDF/B evaluations of neutron-cross section data extend only to 20 MeV (with little data above 15 MeV) there is a great need for neutron data from 15 to 50 MeV for the FMIT facility. Furthermore, nuclear reaction cross sections induced by deuterons up to 35 MeV are a vital part of design and operation considerations, and are even less well understood than the neutron data. The time scale of the design of the FMIT facility has been so rapid that it …
Date:
April 1, 1980
Creator:
Johnson, D. L.; Mann, F. M. & Schenter, R. E.
System:
The UNT Digital Library
Workshop on nuclear dynamics
Separate abstracts were prepared for the 25 papers presented. (WHK)
Date:
April 1, 1982
Creator:
unknown
System:
The UNT Digital Library
Hyperons in neutron stars
Generalized beta equilibrium involving nucleons, hyperons, and isobars is examined for neutron star matter. The hyperons produce a considerable softening of the equation of state. It is shown that the observed masses of neutron stars can be used to settle a recent controversy concerning the nuclear compressibility. Compressibilities less than 200 MeV are incompatible with observed masses. 7 refs., 9 figs.
Date:
April 1, 1986
Creator:
Glendenning, N.K.
System:
The UNT Digital Library
Innovative technology demonstration
The Innovative Technology Demonstration (ITD) program at Tinker Air Force Base (TAFB), Oklahoma City, Oklahoma, will demonstrate the overall utility and effectiveness of innovative technologies for site characterization, monitoring, and remediation of selected contaminated test sites. The current demonstration test sites include a CERCLA site on the NPL list, located under a building (Building 3001) that houses a large active industrial complex used for rebuilding military aircraft, and a site beneath and surrounding an abandoned underground tank vault used for storage of jet fuels and solvents. The site under Building 3001 (the NW Test Site) is contaminated with TCE and Cr{sup {plus}6}; the site with the fuel storage vault (the SW Tanks Site) is contaminated with fuels, BTEX and TCE. These sites and others have been identified for cleanup under the Air Force's Installation Restoration Program (IRP). This document describes the demonstrations that have been conducted or are planned for the TAFB.
Date:
April 1, 1992
Creator:
Anderson, D.B.; Luttrell, S.P. (Pacific Northwest Lab., Richland, WA (United States)); Hartley, J.N. (Battelle Environmental Management Operations, Richland, WA (United States)) & Hinchee, R. (Battelle, Columbus, OH (United States))
System:
The UNT Digital Library
Heat transfer in inertial confinement fusion reactor systems
The short time and deposition distance for the energy from inertial fusion products results in local peak power densities on the order of 10/sup 18/ watts/m/sup 3/. This paper presents an overview of the various inertial fusion reactor designs which attempt to reduce these peak power intensities and describes the heat transfer considerations for each design.
Date:
April 23, 1980
Creator:
Hovingh, J.
System:
The UNT Digital Library
Analytical methods for large-scale sensitivity analysis using GRESS (GRadient Enhanced Software System) and ADGEN (Automated Adjoint Generator)
Sensitivity analysis is an established methodology used by researchers in almost every field to gain essential insight in design and modeling studies and in performance assessments of complex systems. Conventional sensitivity analysis methodologies, however, have not enjoyed the widespread use they deserve considering the wealth of information they can provide, partly because of their prohibitive cost or the large initial analytical investment they require. Automated systems have recently been developed at ORNL to eliminate these drawbacks. Compilers such as GRESS and ADGEN now allow automatic and cost effective calculation of sensitivities in FORTRAN computer codes. In this paper, these and other related tools are described and their impact and applicability in the general areas of modeling, performance assessment and decision making for radioactive waste isolation problems are discussed. 7 refs., 2 figs.
Date:
April 1, 1988
Creator:
Pin, F.G.
System:
The UNT Digital Library
Potential for supplying solar thermal energy to industrial unit operations
Previous studies have identified major industries deemed most appropriate for the near-term adoption of solar thermal technology to provide process heat; these studies have been based on surveys that followed standard industrial classifications. This paper presents an alternate, perhaps simpler analysis of this potential, considered in terms of the end-use of energy delivered to industrial unit operations. For example, materials, such as animal feed, can be air dried at much lower temperatures than are currently used. This situation is likely to continue while economic supplies of natural gas are readily available. However, restriction of these supplies could lead to the use of low-temperature processes, which are more easily integrated with solar thermal technology. The adoption of solar technology is also favored by other changes, such as the relative rates of increase of the costs of electricity and natural gas, and by energy conservation measures. Thus, the use of low-pressure steam to provide process heat could be replaced economically with high-temperature hot water systems, which are more compatible with solar technology. On the other hand, for certain operations such as high-temperature catalytic and distillation processes employed in petroleum refining, there is no ready alternative to presently employed fluid fuels.
Date:
April 1, 1980
Creator:
May, E.K.
System:
The UNT Digital Library
Irradiation effects on the electrochemistry and corrosion resistance of stainless steel
Nickel-ion irradiation at 500{degrees}C is shown to have a strong effect on the surface electrochemistry and intergranular corrosion of stainless steel. Measured current densities in a 1N H{sub 2}SO{sub 4} solution at room temperature are increased at active-passive, passive, and transpassive potentials. Irradiation effects on the current decay behavior and susceptibility to intergranular corrosion were similar for a microcrystalline, fine-grained stainless alloy and for a very large-grained stainless steel. Radiation-induced segregation at the surface is believed to promote higher currents, whereas segregation at grain boundaries prompts intergranular attack. Analytical electron microscopy measurements reveal silicon enrichment and chromium depletion at internal interfaces in irradiated specimens. Silicon enhances dissolution at transpassive potentials, whereas chromium depletion does the same at active-passive and passive potentials.
Date:
April 1, 1992
Creator:
Bruemmer, S. M.; Arey, B. W.; Windisch, C. F., Jr. & Cole, J. I.
System:
The UNT Digital Library
Cross-hole investigation of a rock mass subjected to heating
A cross-hole high-frequency acoustic investigation of a granitic rock mass subjected to sustained heating is reported. Compressional and shear-wave velocity measurements along four different paths between four vertical boreholes made prior to turning on the heater, during 398 days of heating and after the heater was turned off correlated well with the presence of fracture zones, in which the fractures were closed by thermal expansion of the rock upon heating. When the rock mass cooled, the velocity measurements indicated a greater intensity of fracturing than had existed prior to heating. Laboratory compressional and shear-wave velocity measurements have been made on intact rock specimens obtained from the site and subjected to axial stress. When used to interpret the increases in velocities measured in the field upon heating the rock mass, increases in horizontal normal stresses to between 30 and 40 MPa were inferred. Increases of these magnitudes agree with stress measurements made by the other techniques. The ratio of measured compressional to shear-wave velocity appears to provide a sensitive measure of the fraction of crack porosity containing water or gas.
Date:
April 1, 1980
Creator:
Paulsson, B.N.P. & King, M.S.
System:
The UNT Digital Library
Zero-field. mu. SR and low-temperature. mu. /sup +/ diffusivity in copper
In this paper the history of ..mu../sup +/ diffusion studies in copper, with particular emphasis on the increased low-temperature diffusivity which has been known for several years now, is reviewed. The theory and practice of the zero-field ..mu..SR method, which has come into increasing favor in the study of muon diffusion and trapping in metals, is surveyed, and its application to the low-temperature copper problem is discussed. 26 references.
Date:
April 1, 1983
Creator:
Clawson, C.W.
System:
The UNT Digital Library
An automated tool for evaluating compliance and providing assistance with building energy standards during design
In an effort to encourage the maximum cost-effective level of energy efficiency in new building design, energy-efficiency standards have become more location-specific and performance-based. As a result, standards often provide more than one path for ensuring and demonstrating that a design complies, but at the cost of increased complexity. In addition, the burden of remedying a noncompliant design rests on the designers' knowledge and experience, with only general guidance provided by the standards. As part of efforts in the US Department of Energy's (DOE's) Advanced Energy Design and Operation Technologies (AEDOT) project, a team at DOE's Pacific Northwest Laboratory is developing a computer program known as the Energy Standards Intelligent Design Tool (ES-IDT). The ES-IDT is one component of a prototype computer-based building design environment. It performs automatic compliance checking for parts of ASHRAE/IES Standard 90.1-1989 and provides designers assistance in bringing noncomplying designs into compliance. This paper describes the ES-IDT, the functions it provides, and how it is integrated into the design process via the AEDOT prototype building design environment. 9 refs.
Date:
April 30, 1992
Creator:
Quadrel, R.W.; Brambley, M.R. & Stratton, R.C.
System:
The UNT Digital Library
Divertor material evaluation system at DIII-D
The DIvertor Material Evaluation System (DIMES) at DIII-D is a collaborative program between General Atomics, Sandia National Laboratories (SNL), and Argonne National Laboratory (ANL). This program was initiated in response to the need for understanding the interaction between the plasma and divertor surface materials in tokamaks. Material erosion, tritium retention, disruption effects and material transport are very important topics for the design of ITER. The first phase of the DIMES study is integral material exposure measurements. The second phase of the study is the installation of the DIMES sample changer mechanism. The mechanical design goal for the second phase is to allow the insertion of instrumented samples into the bottom divertor plat region of DIII-D without venting the tokamak. Different material samples can then be exchanged overnight after as few as one plasma shot of exposure. This paper presents the results of the integral experiments, the design of the DIMES sample changer mechanism and the planning of material evaluation experiments at DIII-D using the DIMES mechanism.
Date:
April 1, 1992
Creator:
Wong, C. P. C.; Jungle, R.; Phelps, R. D.; Politzer, P.; Puhn, F.; West, W. P. (General Atomics, San Diego, CA (United States)) et al.
System:
The UNT Digital Library
Stellar core collapse and supernova
Massive stars that end their stable evolution as their iron cores collapse to a neutron star or black hole long been considered good candidates for producing Type II supernovae. For many years the outward propagation of the shock wave produced by the bounce of these iron cores has been studied as a possible mechanism for the explosion. For the most part, the results of these studies have not been particularly encouraging, except, perhaps, in the case of very low mass iron cores or very soft nuclear equations of state. The shock stalls, overwhelmed by photodisintegration and neutrino losses, and the star does not explode. More recently, slow late time heating of the envelope of the incipient neutron star has been found to be capable of rejuvenating the stalled shock and producing an explosion after all. The present paper discusses this late time heating and presents results from numerical calculations of the evolution, core collapse, and subsequent explosion of a number of recent stellar models. For the first time they all, except perhaps the most massive, explode with reasonable choices of input physics. 39 refs., 17 figs., 1 tab.
Date:
April 1, 1985
Creator:
Wilson, J. R.; Mayle, R.; Woosley, S. E. & Weaver, T.
System:
The UNT Digital Library