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Error Analysis of Acceleration Control Loops of a Synchrotron

Description: For beam control during acceleration, it is conventional to derive the frequency from an external reference, be it a field marker or an external oscillator, to provide phase and radius feedback loops to ensure the phase stability, radial position and emittance integrity of the beam. The open and closed loop behaviors of both feedback control and their response under the possible frequency, phase and radius errors are derived from fundamental principles and equations. The stability of the loops … more
Date: January 1, 1991
Creator: Zhang, S. Y. & Weng, W. T.
Partner: UNT Libraries Government Documents Department
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Solder fatigue reduction in point focus photovoltaic concentrator modules

Description: Solder fatigue tests have been conducted on point focus photovoltaic concentration cell assemblies to identify a baseline fatigue life and to quantify the fatigue life improvements that result using a copper-molybdenum-copper low-expansion insert between the solar cell and copper heat spreader. Solder microstructural changes and fatigue crack growth were identified using cross sections and ultrasonic scans of the fatigue solder joints. The Coffin-Manson and Total Strain fatigue models for low-c… more
Date: January 1, 1991
Creator: Hund, T. D. & Burchett, S. N.
Partner: UNT Libraries Government Documents Department
open access

An overview of acoustic telemetry

Description: Acoustic telemetry has been a dream of the drilling industry for the past 50 years. It offers the promise of data rates which are one-hundred times greater than existing technology. Such a system would open the door to true logging-while-drilling technology and bring enormous profits to its developers. The basic idea is to produce an encoded sound wave at the bottom of the well, let it propagate up the steel drillpipe, and extract the data from the signal at the surface. Unfortunately, substant… more
Date: January 1, 1992
Creator: Drumheller, D. S.
Partner: UNT Libraries Government Documents Department
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Fermi molecular dynamics

Description: classical many body models supplemented by repulsive momentum-dependent potentials to simulate the Pauli and Heisenberg principles have been use with some success for nuclear and atomic bound state and collision problems. They are capable of describing mean ground state properties, hydrodynamics, shocks (if warranted by the physics), viscosity, correlations, clustering, fragmentation, etc. We have become interested in the Feldmeier Gaussian packet formulation since it is based on a variational … more
Date: January 1, 1991
Creator: Wilets, L. & Beck, W.
Partner: UNT Libraries Government Documents Department
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Object-oriented data handling system for an automated chemistry laboratory

Description: The environmental-remediation efforts at DOE complexes require characterizing problems at each site before cleanup action. Characterization will require the chemical analysis of millions of samples at a significant cost. Automation of the required chemical analyses methods provides a cost-effective solution. An object-oriented approach was deemed necessary to allow for modularization, maintainability, reusability, and flexibility of the software and hardware. Each chemical analysis method is im… more
Date: January 1, 1991
Creator: Medvick, P.A.; Mniszewski, S.M. & Beugelsdijk, T.J.
Partner: UNT Libraries Government Documents Department
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Nonlinear optical properties of new KTiOPO sub 4 isostructures

Description: The atomic structures of the nonlinear optical materials potassium titanyl phosphate (KTiOPO{sub 4}, or KTP) and potassium titanyl arsenate (KTiOAsO{sub 4}) feature one-dimensional channels through which the potassium ions are relatively free to migrate. Ion exchange results when these materials are immersed in molten salts containing alkali metal ions. Sodium, lithium and silver all exchange readily for K{sup +} single crystals of both KTP and KTA to yield the exchanged derivatives Na{sub .95}… more
Date: January 1, 1991
Creator: Phillips, M. L. F.; Harrison, W. T. A. & Stucky, G. D.
Partner: UNT Libraries Government Documents Department
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Conduct of operations: The foundation of safety -- An overview

Description: This paper discusses issues and approaches dealing with conceptualizing, implementing, and maintaining configuration control commensurate with the conduct of operations approach defined by DOE ORDER 5480.19. Specific topics reviewed will include key elements of assessments to determine the status quo such as assessment criteria, assessment personnel, and assessment scope; administrative programs to maintain the status quo such as organizational definition, responsibilities, interfaces, and prio… more
Date: May 1, 1992
Creator: Willett, D.J. & Hertel, N.E.
Partner: UNT Libraries Government Documents Department
open access

Superconductivity: Past, present, and future

Description: This paper provides an overview of superconductor research and development activities, with emphasis on the potential of high-{Tc} materials for future applications. Superconductor applications are grouped under the following categories: electronics/instrumentation, bulk material/castings, research devices, industrial/commercial, electric power, and transportation/propulsion. Near-term applications are typically based on thin film and cast forms of high-{Tc} materials, while large-scale applica… more
Date: January 1, 1992
Creator: Uherka, K.L.
Partner: UNT Libraries Government Documents Department
open access

Edge-on ion irradiation of electron microscope specimens

Description: A special technique is described for in situ transmission electron microscope (TEM) experiments involving simultaneous ion irradiation, in which the resultant phenomena are observed as in a cross-section TEM specimen. That is, instead of ion-irradiating the film or foil specimen normal to the major surfaces and observing in plan view (i.e., in the same direction), the specimen is irradiated edge-on (i.e., parallel to the major surfaces) and is observed normal to the depth direction with respect… more
Date: January 1, 1992
Creator: Otero, M. P. & Allen, C. W.
Partner: UNT Libraries Government Documents Department
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Three-dimensional free electron laser dispersion relation including betatron oscillations

Description: We have developed a 3-D FEL theory based upon the Maxwell-Vlasov equations including the effects of the energy spread and emittance of the electron beam, and of betatron oscillations. The radiation field is expressed in terms of the Green's function of the inhomogeneous wave equation and the distribution function of the electron beam. The distribution function is expanded in terms of a set of orthogonal functions determined by the unperturbed particle distribution. The coupled Maxwell-Vlasov eq… more
Date: August 1, 1991
Creator: Chin, Y. H.; Kim, K. J. & Xie, M.
Partner: UNT Libraries Government Documents Department
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Effect of high aspect ratio on ITER maintenance design

Description: The International Thermonuclear Experimental Reactor (ITER) baseline machine configuration and auxiliary systems design specify maintainability and repairability as fundamental requirements. Two important maintenance requirements for ITER are a device that is fully remotely maintainable, with the provision for hands-on maintenance wherever possible, and the ability to maintain components with short lives or high failure rates without moving other components or disturbing the machine's internal … more
Date: January 1, 1991
Creator: Herrick, T.J.; Davis, F.C.; Hollis, M.J. & Lousteau, D.C.
Partner: UNT Libraries Government Documents Department
open access

ADIFOR: Automatic differentiation in a source translator environment

Description: The numerical methods employed in the solution of many scientific computing problems require the computation of derivatives of a function f: R{sup n} {yields} R{sup m}. ADIFOR (Automatic Differentiation in FORtran) is a source transformation tool that accepts Fortran 77 code for the computation of a function and writes portable Fortran 77 code for the computation of the derivatives. In contrast to previous approaches, ADIFOR views automatic differentiation as a source transformation problem and… more
Date: January 1, 1992
Creator: Bischof, C.; Corliss, G.; Griewank, A. (Argonne National Lab., IL (United States)) & Carle, A. (Rice Univ., Houston, TX (United States). Center for Research on Parallel Computation)
Partner: UNT Libraries Government Documents Department
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Laser diagnostics of H sup minus formation in a magnetic multicusp ion source

Description: The populations of ground electronic state atomic hydrogen and ground electronic state, vibrationally-rotationally excited hydrogen molecules in a negative hydrogen ion source discharge have been measured using vacuum ultraviolet (VUV) laser absorption spectroscopy. Vibrational states up to v=8 and rotational levels as high as J=15 have been measured. The measurements have been made under a range of discharge conditions. The complete vibrational population distribution for v=1-8, J=1 has been o… more
Date: May 1, 1991
Creator: Young, A. T.; Chen, P.; Kunkel, W. B.; Leung, K. N.; Li, C. Y. & Stutzin, G. C.
Partner: UNT Libraries Government Documents Department
open access

The product consistency test for the DWPF wasteform

Description: The preliminary specifications on the glass wasteform to be produced by the Defense Waste Processing Facility (DWPF) require extensive characterization of the glass product both before actual production begins and then during production. To aid in this characterization, a leach test was needed that was easily reproducible, could be performed remotely on highly radioactive samples, and could yield results rapidly. Several standard leach tests were examined with a variety of test configurations. … more
Date: January 1, 1990
Creator: Jantzen, Carol M. & Bibler, N. E.
Partner: UNT Libraries Government Documents Department
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Atomic structure of clusters through chemical reactions

Description: Techniques for the probing of isolated metal cluster structure through adsorbate binding patterns will be described. The saturation of clusters with reagents such as ammonia and nitrogen provides information on the number of preferred binding sites for these reagents. The dependence of this number on cluster size can suggest particular structural themes. The equilibrium reaction with water can be used to identify cluster sizes having especially enhanced binding for the water molecule. Again, th… more
Date: January 1, 1991
Creator: Riley, S.J.
Partner: UNT Libraries Government Documents Department
open access

The Advanced Light Source U8 beam line, 20--300 eV

Description: The U8 is a beam line under construction at the Advanced Light Source (ALS). The beam line will be described along with calculations of its performance and its current status. An 8 cm period undulator is followed by two spherical collecting mirrors, an entrance slit, spherical gratings having a 15{degree} deviation angle, a moveable exit slit, and refocusing and branching mirrors. Internal water cooling is provided to the metal M1 and M2 mirrors as well as to the gratings. Calculations have bee… more
Date: October 1, 1991
Creator: Heimann, P.; Warwick, T.; Howells, M.; McKinney, W.; Digennaro, D.; Gee, B. et al.
Partner: UNT Libraries Government Documents Department
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Analysis of erosion and transport of carbon impurity in the TFTR inner bumper limiter region

Description: Carbon sputtering and transport on the TFTR inner graphite bumper limiter is investigated with the impurity transport code REDEP. Analysis is carried out for a series of ohmic discharges in TFTR. Predictions for Z{sub eff} in the core plasma agree well with in-situ experimental measurements. Run-away self-sputtering of carbon is predicted at low densities and high edge plasma temperatures when the limiter surface was purged of deuterium. Surface erosion and deposition is analyzed. In general, r… more
Date: January 1, 1992
Creator: Hua, T. Q. & Brooks, J. N.
Partner: UNT Libraries Government Documents Department
open access

The electronics and data acquisition system for the Wire Imaging Synchrotron Radiation Detector at the SLC (Stanford Linear Collider)

Description: The Stanford Linear Collider (SLC) located at the Stanford Linear Accelerator Center collides electrons and positrons produced in the linear accelerator pulse by pulse. We determine the energy of each beam by measuring the angle of deflection of the beam in the SLC extraction lines. Each extraction line consists of two bending magnets that produce synchrotron radiation, and a spectrometer analyzing magnet that deflects the beam. We detect the synchrotron light by using the emission of electrons… more
Date: January 1, 1990
Creator: Rouse, F.; Briggs, D.D. (Stanford Linear Accelerator Center, Menlo Park, CA (USA)); Gomez, J.J.; Von Zanthier, C. & Kent, J. (California Univ., Santa Cruz, CA (USA))
Partner: UNT Libraries Government Documents Department
open access

The Fresh-Bunch' technique in FELs

Description: The 'Fresh Bunch' technique is being proposed as a method of increasing the gain and power of FEL amplifiers in which the length of the optical radiation pulse is shorter than the length of the electron bunch. In multi-stage FEL, electron beam energy spread is increased by the FEL interaction in the early stages. In the 'Fresh Bunch' technique, the low energy spread of the electron beam is recovered by shifting the radiation pulse to an undisturbed part of the electron bunch, thus improving the… more
Date: January 1, 1991
Creator: Ben-Zvi, Ilan; Yang, K. M. & Yu, L. H.
Partner: UNT Libraries Government Documents Department
open access

Surface, interface and thin-film magnetism

Description: 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 developme… more
Date: July 1, 1991
Creator: Falicov, L.M. (Lawrence Berkeley Lab., CA (United States) California Univ., Berkeley, CA (United States). Dept. of Physics)
Partner: UNT Libraries Government Documents Department
open access

Visual tools and languages: Directions for the '90s

Description: We identify and discuss three domains where we believe that innovative application of visual programming languages is likely to make a significant impact in the near term: concurrent computing, computer-based assistance for people with disabilities, and the multimedia/multimodal environments of tomorrow in which it will be possible to hear and physically interact with information as well as see it. 33 refs., 3 figs.
Date: January 1, 1991
Creator: Glinert, E.P. (Rensselaer Polytechnic Inst., Troy, NY (United States). Dept. of Computer Science); Blattner, M.M. (Lawrence Livermore National Lab., CA (United States)) & Frerking, C.J. (California Univ., Davis, CA (United States))
Partner: UNT Libraries Government Documents Department
open access

An optimized algorithm for solving the nodal diffusion method on shared memory multiprocessors

Description: Nodal methods play a special role in reactor physics calculations. In recent papers the high computational efficiency of nodal methods has been established and the development of more efficient algorithms tailored to the advanced architectures of modern day computers proposed. The rapidly changing architectures of today's computer influence the way codes have to be programmed so that reasonable speed up and efficiency are attained. We have applied these concepts in solving the one-group neutron… more
Date: January 1, 1990
Creator: Kirk, B.L. & Azmy, Y.Y.
Partner: UNT Libraries Government Documents Department
open access

Static magnetic fields: A summary of biological interactions, potential health effects, and exposure guidelines

Description: Interest in the mechanisms of interaction and the biological effects of static magnetic fields has increased significantly during the past two decades as a result of the growing number of applications of these fields in research, industry and medicine. A major stimulus for research on the bioeffects of static magnetic fields has been the effort to develop new technologies for energy production and storage that utilize intense magnetic fields (e.g., thermonuclear fusion reactors and superconduct… more
Date: May 1, 1992
Creator: Tenforde, T.S.
Partner: UNT Libraries Government Documents Department
open access

SOILD: A computer model for calculating the effective dose equivalent from external exposure to distributed gamma sources in soil

Description: The SOLID computer model was developed for calculating the effective dose equivalent from external exposure to distributed gamma sources in soil. It is designed to assess external doses under various exposure scenarios that may be encountered in environmental restoration programs. The models four major functional features address (1) dose versus source depth in soil, (2) shielding of clean cover soil, (3) area of contamination, and (4) nonuniform distribution of sources. The model is also capab… more
Date: January 1, 1991
Creator: Chen, S. Y.; LePoire, D.; Yu, C. (Argonne National Lab., IL (United States)); Schafetz, S. (Rockland Community Coll., Suffern, NY (United States)) & Mehta, P. (Fayetteville State Univ., NC (United States))
Partner: UNT Libraries Government Documents Department
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