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335
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169
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148
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132
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73
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28
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20
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14
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Design and performance of liquid hydrogen target systems for the Fermilab Fixed Target Program
The Fermilab 1990--1991 Fixed Target Program featured six experiments utilizing liquid hydrogen or liquid deuterium targets as part of their apparatus. Each design was optimized to the criteria of the experiment, resulting in variations of material selection, methods of refrigeration and secondary containment. Collectively, the targets were run for a total of 14,184 hours with an average operational efficiency of 97.6%. The safe and reliable operation of these targets was complemented by an increased degree of documentation and component testing. This operation was also aided by several key upgrades. All the systems were designed and fabricated under a set of written guidelines that blend analytical calculations and empirical guidance drawn from over twenty years of target fabrication experience. 3 refs., 4 tabs.
Date:
July 1, 1991
Creator:
Allspah, D.; Danes, J.; Peifer, J. & Stanek, R.
Object Type:
Article
System:
The UNT Digital Library
Inexpensive cross-flow hydropower turbine at Arbuckle Mountain Hydroelectric Project
This report documents the first three and half years of operation and maintenance on the Arbuckle Mountain Hydroelectric Project. Located on a flashy mountain stream in northern California, the project was designed, built and tested through a Cooperative Agreement between the US DOE and OTT Engineering, Inc. (OTT). The purpose of the Agreement is to build and intensively test an inexpensive American-made cross-flow turbine and to provide information to the DOE on the cost, efficiency, operation, and maintenance of the unit. It requires that OTT document for DOE a summary of the complete operating statistics, operation and maintenance cost, and revenues from power sales for a two-year operating period. Several unique events occurred between the initial start-up (December 1986) and the beginning of the 1989 generation season (October 1988) that delayed the first year's full operation and provided unique information for a demonstration project of this type. Accordingly, this report will discuss certain major problems experienced with the design, operation and maintenance, and energy production, as well as the operation and maintenance costs and value of the power produced for the first three and half years of operation. 9 figs., 2 tabs.
Date:
July 1, 1991
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
Theory of ordering transformations in metals and minerals
This dissertation presents an investigation of ordering in FCC based systems using the pair potential approximation in the ground state and mean field limits. The theoretical approach is used to explain the occurrence of observed equilibrium phases and characteristics of thermodynamic instabilities, in particular, spinodal ordering and decomposition. It is shown that the stability of non-integer domain sizes in long period superstructures such as Al{sub 3}Ti and Ag{sub 3}Mg may result from the tendency of a system to reduce the number of non-dominant ordering waves, thus producing domain sizes that have rational fraction form n/m. This conclusion is used to explain the domain size stability with respect to variations in temperature and electron concentration. The cation ordering in the precipitate phases in calcite and dolomite is analyzed by analogy with ordering in FCC based metals. The ordered phases in calcite and dolomite are shown to be consistent with pair potential minima at {l brace}100{r brace} and {l brace}1/2, 1/2, 1/2{r brace} positions in reciprocal space respectively. 32 refs., 6 figs.
Date:
July 1, 1991
Creator:
Lindsey, Timothy Francis
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Study of ICRF wave propagation and plasma coupling efficiency in a linear magnetic mirror device
Ion Cyclotron Range of Frequency (ICRF) wave propagation in an inhomogeneous axial magnetic field in a cylindrical plasma-vacuum system has historically been inadequately modelled. Previous works either sacrifice the cylindrical geometry in favor of a simpler slab geometry, concentrate on the resonance region, use a single mode to represent the entire field structure, or examine only radial propagation. This thesis performs both analytical and computational studies to model the ICRF wave-plasma coupling and propagation problem. Experimental analysis is also conducted to compare experimental results with theoretical predictions. Both theoretical as well as experimental analysis are undertaken as part of the thesis. The theoretical studies simulate the propagation of ICRF waves in an axially inhomogeneous magnetic field and in cylindrical geometry. Two theoretical analysis are undertaken - an analytical study and a computational study. The analytical study treats the inhomogeneous magnetic field by transforming the (r,z) coordinate into another coordinate system ({rho},{xi}) that allows the solution of the fields with much simpler boundaries. The plasma fields are then Fourier transformed into two coupled convolution-integral equations which are then differenced and solved for both the perpendicular mode number {alpha} as well as the complete EM fields. The computational study involves a multiple …
Date:
July 1, 1991
Creator:
Peng, S.Y.
Object Type:
Report
System:
The UNT Digital Library
Ceramic technology for Advanced Heat Engines Project
Significant accomplishments in fabricating ceramic components for advanced heat engine programs have provided evidence that the operation of ceramic parts in high-temperature engine environments is feasible. However, these programs have also demonstrated that additional research is needed in materials and processing development, design methodology, and database and life prediction before industry will have a sufficient technology base from which to produce reliable cost-effective ceramic engine components commercially. An assessment of needs was completed, and a five year project plan was developed with extensive input from private industry. The project approach includes determining the mechanisms controlling reliability, improving processes for fabricating existing ceramics, developing new materials with increased reliability, and testing these materials in simulated engine environments to confirm reliability. Although this is a generic materials project, the focus is on the structural ceramics for advanced gas turbine and diesel engines, ceramic bearings and attachments, and ceramic coatings for thermal barrier and wear applications in these engines. To facilitate the rapid transfer of this technology to US industry, the major portion of the work is being done in the ceramic industry, with technological support from government laboratories, other industrial laboratories, and universities. This project is managed by ORNL for the Office …
Date:
July 1, 1991
Creator:
Johnson, D. R.
Object Type:
Report
System:
The UNT Digital Library
Surface, interface and thin-film magnetism
In the last quarter of the 20th century, with the information revolution and the ever growing need to acquire, store, and retrieve information, the science and technologies attached to magnetic recording have experienced an explosive growth. Central to those pursuits has been the materials science of magnetism as it applies to surfaces, interfaces, and thin films. This report discusses topics on thin-film magnetism such as: theory, physical effects, prospects, opportunities and future developments. (JL)
Date:
July 1, 1991
Creator:
Falicov, L.M. (Lawrence Berkeley Lab., CA (United States) California Univ., Berkeley, CA (United States). Dept. of Physics)
Object Type:
Article
System:
The UNT Digital Library
Studies of Plasma Transport
This report discusses the charge-coupled device camera and other plasma diagnostic equipment used to measure plasma density and other plasma properties. (LSP)
Date:
July 22, 1991
Creator:
Malmberg, J. H.; O'Neil, T. M. & Driscoll, C. F.
Object Type:
Report
System:
The UNT Digital Library
A search for the production of the final states. tau. sup +. tau. sup minus e sup + e sup minus ,. tau. sup +. tau. sup minus. mu. sup +. mu. sup minus , and. tau. sup +. tau. sup minus. pi. sup +. pi. sup minus in e sup + e sup minus collisions at radical s = 29 GeV
We have searched for the reaction e{sup +}e{sup {minus}} {yields} {tau}{sup +}{tau}{sup {minus}}{bar f}f, where f is either an electron, muon, or charged pion, at {radical}s = 29 GeV using the Mark 2 detector at the PEP storage ring. One candidate event is found while 2.3 events are expected from known processes. We would expect to see 11 events if the cross-section for e{sup +}e{sup {minus}} {yields} {tau}{sup +}{tau}{sup {minus}}{bar f}f at {radical}s = 29 GeV were enhanced by the factor of 4.7 which the ALEPH collaboration reports for {radical}s = 91 GeV. we also look for e{sup +}e{sup {minus}} {yields} e{sup +}e{sup {minus}}{bar f}f and e{sup +}e{sup {minus}} {yields} {mu}{sup +}{mu}{sup {minus}} {bar f}f, and for e{sup +}e{sup {minus}} {yields} {tau}{sup +}{tau}{sup {minus}} {gamma} using a similar analysis procedure and see the number of events predicted by the standard model. 10 refs., 5 figs., 3 tabs.
Date:
July 1, 1991
Creator:
unknown
Object Type:
Article
System:
The UNT Digital Library
Geophysics: Building E5032 decommissioning, Aberdeen Proving Ground
integration of data from surveys using three geophysical technologies has provided information used to define the locations of buried utilities, tanks, vaults, and debris near building E5032 at the Aberdeen Proving Ground. Ground penetrating radar (GPR) profiles indicate the presence of buried pipes, tanks, reinforcement rods (rebar), and remnants of railroad tracks. A magnetic map constructed from a detailed magnetic survey on the north side of the building outlines buried iron-rich objects that are interpreted to be iron pipes, tank, and other debris of uncertain origin at relatively shallow depths. Horizontal electrical resistivity surveys and vertical electrical resistivity soundings essentially corroborated the findings obtained with the magnetometer and GPR. In addition, a highly resistance layer was observed on the east side of the building where a former railroad bed with a thick grave fill is believed to immediately underlie the lawn. The resistivity data show no evidence of a conductive leachate plume. Geophysical measurements from three techniques over a buried concrete slab approximately 130 ft north of Building E5032 give geophysical signatures interpreted to be due to the presence of a large iron tank or vault. An attempt was made to gather meaningful magnetic data on the east, west, and …
Date:
July 1, 1991
Creator:
McGinnis, L.D. & Miller, S.F.
Object Type:
Report
System:
The UNT Digital Library
Acceleration of electrons using an inverse free electron laser auto- accelerator
We present data from our study of a device known as the inverse free electron laser. First, numerical simulations were performed to optimize the design parameters for an experiment that accelerates electrons in the presence of an undulator by stimulated absorption of radiation. The Columbia free electron laser (FEL) was configured as an auto-accelerator (IFELA) system; high power (MW's) FEL radiation at {approximately}1.65 mm is developed along the first section of an undulator inside a quasi-optical resonator. The electron beam then traverses a second section of undulator where a fraction of the electrons is accelerated by stimulated absorption of the 1.65 mm wavelength power developed in the first undulator section. The second undulator section has very low gain and does not generate power on its own. We have found that as much as 60% of the power generated in the first section can be absorbed in the second section, providing that the initial electron energy is chosen correctly with respect to the parameters chosen for the first and second undulators. An electron momentum spectrometer is used to monitor the distribution of electron energies as the electrons exit the IFELA. We have found; using our experimental parameters, that roughly 10% of …
Date:
July 1, 1992
Creator:
Wernick, I.K. & Marshall, T.C.
Object Type:
Report
System:
The UNT Digital Library
Influences of clouds and rain on the large-scale transport and deposition of sulfur
This paper describes the application of a three-dimensional, global-scale Eulerian model with an explicit description of cloud and chemical processes. Simulation results describing the transport of sulfur from North America and Europe across the north Atlantic Ocean during a climatological July are presented. Wet deposition was found to contribute slightly more to total sulfur deposition than dry deposition, a feature explained by the large amounts of precipitation during this month. The wet deposition patterns did not always correspond to the emissions patterns. The precipitation rate and spatial distribution had a large effect on the calculated concentrations of soluble sulfur species. 10 refs., 7 figs., 1 tab.
Date:
July 1, 1991
Creator:
Luecken, D.J.; Berkowitz, C.M. & Easter, R.C.
Object Type:
Article
System:
The UNT Digital Library
Savannah River Site computing architecture migration guide
The SRS Computing Architecture is a vision statement for site computing which enumerates the strategies which will guide SRS computing efforts for the 1990s. Each strategy is supported by a number of feature statements which clarify the strategy by providing additional detail. Since it is a strategic planning document, the Architecture has sitewide applicability and endorsement but does not attempt to specify implementation details. It does, however, specify that a document will be developed to guide the migration from the current site environment to that envisioned by the new architecture. The goal of this document, the SRS Computing Architecture Migration Guide, is to identify specific strategic and tactical tasks which would have to be completed to fully implement the architectural vision for site computing as well as a recommended sequence and timeframe for addressing these tasks. It takes into account the expected availability of technology, the existing installed base, and interdependencies among architectural components and objectives.
Date:
July 30, 1991
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
Two-dimensional nuclear magnetic resonance studies of molecular structure in liquids and liquid crystals
Magnetic couplings between protons, such as through-space dipole couplings, and scalar J-couplings depend sensitively on the structure of the molecule. Two dimensional nuclear magnetic resonance experiments provide a powerful tool for measuring these couplings, correlating them to specific pairs of protons within the molecule, and calculating the structure. This work discusses the development of NMR methods for examining two such classes of problems -- determination of the secondary structure of flexible molecules in anisotropic solutions, and primary structure of large biomolecules in aqueous solutions. 201 refs., 84 figs., 19 tabs.
Date:
July 1, 1991
Creator:
Rucker, S.P.
Object Type:
Report
System:
The UNT Digital Library
Nonlinear spectroscopic studies of interfacial molecular ordering
The second order nonlinear optical processes of second harmonic generation and sum frequency generation are powerful new probes of surfaces. They possess unusual surface sensitivity due to the symmetry properties of the nonlinear susceptibility. In particular, infrared-visible sum frequency generation (SFG) can obtain the vibrational spectrum of sub-monolayer coverages of molecules. In this thesis, we explore the unique information that can be obtained from SFG. We take advantage of the sensitivity of SFG to the conformation of alkane chains to study the interaction between adsorbed liquid crystal molecules and surfactant treated surfaces. The sign of the SFG susceptibility depends on the sign of the molecular polarizability and the orientation, up or down, of the molecule. We experimentally determine the sign of the susceptibility and use it to determine the absolute orientation to obtain the sign of the molecular polarizability and show that this quantity contains important information about the dynamics of molecular charge distributions. Finally, we study the vibrational spectra and the molecular orientation at the pure liquid/vapor interface of methanol and water and present the most detailed evidence yet obtained for the structure of the pure water surface. 32 refs., 4 figs., 2 tabs.
Date:
July 1, 1991
Creator:
Superfine, R.
Object Type:
Report
System:
The UNT Digital Library
CGVIEW: A program to generate isometric and perspective views of combinatorial geometries
The prototype of a graphical debugger for combinatorial geometry (CG) is described. The prototype debugger consists of two parts: a FORTRAN-based view'' generator and a Microsoft Windows application for displaying the geometry. This document describes the code CGVIEW, which comprises the first part of the system. User-specified options permit the selection of an arbitrary viewpoint in space and the generation of either an isometric or perspective view. Additionally, any combination of zones, materials, or regions can be flagged as invisible to facilitate the inspection of internal details of the geometry. In the same manner, an arbitrary body can be cut away from the geometry to facilitate inspection and debugging. Examples illustrating the various options are described.
Date:
July 1, 1992
Creator:
Burns, T.J.
Object Type:
Report
System:
The UNT Digital Library
Situational simulations in interactive video
The Westinghouse Hanford Company Advanced Training Technologies section is using situational simulations in several Interactive Video training courses. Two applications of situational simulations will be discussed. In the first, used in the Hanford General Employee Training course, the student evaluates employee's actions in simulations of possible workplace situations. In the second, used in the Criticality Safety course, students must follow well-defined procedures to complete tasks. Design and incorporation of situational simulations will be discussed. 3 refs.
Date:
July 1, 1991
Creator:
Smith, L.J.
Object Type:
Article
System:
The UNT Digital Library
Establishment and maintenance of a coal sample bank and data base
In this Project Status Report for 7/9/89--10/8/89, results of a comparative study of coal sample deterioration in several container types were presented. In April 1990, one year after the initial analyses, the set of analyses was repeated on the most important container types. The new results are included in Table 2. During the current reporting period a total of 42 data printouts were distributed. In addition, 7 special data requests were fulfilled by either search/sort and printout or creation of a data disk, resulting in distribution of limited information on 2083 samples. Several preliminary requests for Sample Bank and Data Base information and price quotations have also been handled.
Date:
July 11, 1990
Creator:
Davis, A.
Object Type:
Report
System:
The UNT Digital Library
Beam and viewing dump positioning inside TFTR for CTS alpha-particle diagnostics
A collective Thomson scattering (CTS) diagnostic system for localized measurement of energetic ions is being developed for TFTR. This system will use a 200KW, 56GHz gyrotron and a sensitive heterodyne receiver. In addition, a key element of this system will be beam and viewing dumps which are needed to minimize detection of stray gyrotron and ECE background radiation by the receiver system. It is the purpose of this study to determine the size and location of these dumps inside TFTR taking into account beam refraction and launch and receiver antenna optics scanning. The beam dump must cover all the area in the vacuum chamber where the beam is expected to impinge, and the viewing dump must cover all the areas within the direct line of sight of the receiver antenna. The beam launch system and the receiver antenna are to be placed nearly symmetrically above and below the midplane of the tokamak vacuum vessel, respectively. The beam dump is to be placed at the bottom inside of the vacuum vessel to absorb the gyrotron beam which will be launched from a top port. The viewing dump is expected to be placed symmetrically at the top inside of the vacuum vessel, …
Date:
July 15, 1991
Creator:
Rhee, D.Y.; Woskov, P.P. (Massachusetts Inst. of Tech., Cambridge, MA (United States). Plasma Fusion Center); Ellis, R. & Park, H. (Princeton Univ., NJ (United States). Plasma Physics Lab.)
Object Type:
Report
System:
The UNT Digital Library
Vertical bridgman and gradient freeze growth of III-V compound semiconductors
Major improvements in the structural and electrical perfection of single crystals of III-V compound semiconductors have been achieved by using new vertical Bridgman-type and vertical gradient freeze techniques. A general review of experimental set-ups used for growth of large diameter crystals of GaP, InP and GaAs is presented. Crystal properties and characteristic features are discussed to illustrate advantages and disadvantages of the vertical Bridgman-type growth techniques. 22 refs., 5 figs.
Date:
July 1, 1990
Creator:
Bourret, E.D.
Object Type:
Article
System:
The UNT Digital Library
Po-210 as long-term integrating radon indicator in the indoor environment
The general objective is to improve the knowledge about the transferring processes leading from airborne radon/radon daughters to embedded Po-210 in hard surfaces in the indoor environment. The specific goal of the research is to identify situations in which the surface activity of Po-210 can be used as a long-term indicator of lung cancer risk from past or future radon exposures.
Date:
July 1, 1990
Creator:
Samuelsson, C.
Object Type:
Report
System:
The UNT Digital Library
Advanced Coal Conversion Process Demonstration (Project)
This report contains a description of technical progress made on the Advanced Coal Conversion Process Demonstration Project (ACCP). The project is a US Department of Energy Innovative Clean Coal Technology Project. The cooperative agreement defining the project is between DOE and the Rosebud SynCoal Partnership RSCP. The RSCP is a partnership between Western Energy Company (WECo), a subsidiary of Entech, Montana Power's non-utility group, and NRG, a subsidiary of Northern States Power. The ACCP is a method of upgrading low ranked coals by reducing the moisture and sulfur content and increasing the heating value. The facility is being constructed at WECo's Rosebud No. 6 coal mine, west of Colstrip, Montana. This report contains both a history of the process development and a report of technical progress made since the beginning of the Clean Coal 1 cooperative agreement.
Date:
July 1, 1991
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
Analysis of natural gas supply strategies at Fort Drum
This analysis investigates strategies for Fort Drum to acquire a reliable natural gas supply while reducing its gas supply costs. The purpose of this study is to recommend an optimal supply mix based on the life-cycle costs of each strategy analyzed. In particular, this study is intended to provide initial guidance as to whether or not the building and operating of a propane-air mixing station is a feasible alternative to the current gas acquisition strategy. The analysis proceeded by defining the components of supply (gas purchase, gas transport, supplemental fuel supply); identifying alternative options for each supply component; constructing gas supply strategies from different combinations of the options available for each supply component and calculating the life-cycle costs of each supply strategy under a set of different scenarios reflecting the uncertainty of future events.
Date:
July 1, 1992
Creator:
Stucky, D. J.; Shankle, S. A. & Anderson, D. M.
Object Type:
Report
System:
The UNT Digital Library
Excitation of high-n toroidicity-induced shear Alfven eigenmodes by energetic particles and fusion alpha particles in tokamaks
The stability of high-n toroidicity-induced shear Alfven eigenmodes (TAE) in the presence of fusion alpha particles or energetic ions in tokamaks is investigated. The TAE modes are discrete in nature and thus can easily tap the free energy associated with energetic particle pressure gradient through wave particle resonant interaction. A quadratic form is derived for the high-n TAE modes using gyro-kinetic equation. The kinetic effects of energetic particles are calculated perturbatively using the ideal MHD solution as the lowest order eigenfunction. The finite Larmor radius (FLR) effects and the finite drift orbit width (FDW) effects are included for both circulating and trapped energetic particles. It is shown that, for circulating particles, FLR and FDW effects have two opposite influences on the stability of the high-n TAE modes. First, they have the usual stabilizing effects by reducing the wave particle interaction strength. Second, they also have destabilizing effects by allowing more particles to resonate with the TAE modes. It is found that the growth rate induced by the circulating alpha particles increase linearly with toroidal mode number n for small {kappa}{sub {theta}}{rho}{sub {alpha}}, and decreases as 1/n for {kappa}{sub {theta}}{rho}{sub {alpha}} {much gt} 1. The maximum growth rate is obtained at …
Date:
July 1, 1992
Creator:
Fu, G. Y. & Cheng, C. Z.
Object Type:
Report
System:
The UNT Digital Library
Scale effects in sliding friction: An experimental study
Solid friction is considered by some to be a fundamental property of two contacting materials, while others consider it to be a property of the larger tribosystem in which the materials are contained. A set of sliding friction experiments were designed to investigate the hypothesis that the unlubricated sliding friction between two materials is indeed a tribosystems-related property and that the relative influence of the materials properties or those of the machine on friction varies from one situation to another. Three tribometers were used: a friction microprobe (FMP), a typical laboratory-scale reciprocating pin-on-flat device, and a heavy-duty commercial wear tester. The slider material was stainless steel (AISI 440C) and the flat specimen material was an ordered alloy of Ni{sub 3}Al (IC-50). Sphere-on-flat geometry was used at ambient conditions and at normal forces ranging from 0.01 N to 100 N and average sliding velocities of 0.01 to 100.0 mm/s. The nominal, steady-state sliding friction coefficient tended to decrease with increases in normal force for each of the three tribometers, and the steady state value of sliding friction tended to increase as the mass of the machine increased. The variation of the friction force during sliding was also a characteristic of the …
Date:
July 24, 1991
Creator:
Blau, P.J.
Object Type:
Article
System:
The UNT Digital Library