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Vibration analysis of composite disks.

Description: Often, disks rotating at high speeds are fabricated from high-strength, filament-wound composites. The carbon and glass fiber bundles, or tows that makeup a filament, are often similar in different disk designs, and steady-state stress analyses are usually reported. Typically, little information is reported about the dynamic deformation and vibrations of the disk, which are important for understanding instabilities at high rotational speeds. First, experimental and FEM modal analyses are perfor… more
Date: November 18, 1997
Creator: Gupta, A.; Mulcahy, T. M.; Hull, J. R. & Abboud, R. G.
Partner: UNT Libraries Government Documents Department
open access

Thermal Spray Coatings for Coastal Infrastructure

Description: Several protection strategies for coastal infrastructure using thermal-spray technology are presented from research at the Albany Research Center. Thermal-sprayed zinc coatings for anodes in impressed current cathodic protection systems are used to extend the service lives of reinforced concrete bridges along the Oregon coast. Thermal-sprayed Ti is examined as an alternative to the consumable zinc anode. Sealed thermal-sprayed Al is examined as an alternative coating to zinc dust filled polyure… more
Date: November 1, 1997
Creator: Holcomb, G.R.; Covino, Bernard S., Jr.; Cramer, S. D. & Bullard, S. J.
Partner: UNT Libraries Government Documents Department
open access

Modeling forces in high-temperature superconductors

Description: We have developed a simple model that uses computed shielding currents to determine the forces acting on a high-temperature superconductor (HTS). The model has been applied to measurements of the force between HTS and permanent magnets (PM). Results show the expected hysteretic variation of force as the HTS moves first toward and then away from a permanent magnet, including the reversal of the sign of the force. Optimization of the shielding currents is carried out through a simulated annealing… more
Date: November 18, 1997
Creator: Turner, L. R. & Foster, M. W.
Partner: UNT Libraries Government Documents Department
open access

CASES-97 : Diurnal variation of the fair-weather PBL.

Description: The CASES-97 dataset, supplemented by data from the surrounding area and from satellite, will enable us to isolate the effects of soil moisture on boundary layer evolution.Our initial approach will be to use the integrated dataset to determine (a) the factors that contribute to PBL growth, and (b) the factors that determine the wind, temperature, and wind profiles in the growing PBL. This process will help us to consolidate the dataset and tease out remaining inconsistencies. As soon as reasona… more
Date: November 18, 1997
Creator: Coulter, R. L.; Grossman, R. L.; Hicks, B.; Horst, T.; Klazura, G.; LeMone, M. A. et al.
Partner: UNT Libraries Government Documents Department
open access

Deuteron photodisintegration : new results from TJNAF.

Description: The first measurements of the differential cross section from d({gamma},p)n up to 4.0 GeV were performed at the Thomas Jefferson National Accelerator Facility (TJNAF, formerly CEBAF). Bremsstrahlung photons from electron beam impinging on a copper radiator and a liquid deuterium target were employed for this experiment. The experiment was performed in Hall C where the photoprotons at forward angles in the center-of-mass were detected in the High Momentum Spectrometer (HMS) and photoprotons at b… more
Date: November 18, 1997
Creator: Abbott, D. J.; Ahmidouch, A.; Armstrong, C. S.; Arrington, J.; Cummings, W. J.; Geesaman, D. F. et al.
Partner: UNT Libraries Government Documents Department
open access

The RERTR program.

Description: The Reduced Enrichment Research and Test Reactor (RERTR) Program was established in 1978 at the Argonne National Laboratory (ANL) by the Department of Energy (DOE), which continues to fund the program and to manage it in coordination with the Department of State (DOS), the Arms Control and Disarmament Agency (ACDA), and the Nuclear Regulatory Commission (NRC). The primary objective of the program is to develop the technology needed to use Low-Enrichment Uranium (LEU) instead of High-Enrichment … more
Date: November 14, 1997
Creator: Travelli, A.
Partner: UNT Libraries Government Documents Department
open access

Differences between heavy and light quarks.

Description: The quark Dyson-Schwinger equation shows that there are distinct differences between light and heavy quarks. The dynamical mass function of the light quarks is characterized by a sharp increase below 1 GeV, whereas the mass function of the heavy quarks is approximately constant in this infrared region. As a consequence, the heavy meson masses increase linearly with the current quark masses, whereas the light pseudoscalar meson masses are proportional to the square root of the current quark mass… more
Date: November 10, 1997
Creator: Maris, P. & Roberts, C. D.
Partner: UNT Libraries Government Documents Department
open access

The LEU conversion status of U.S. Research Reactors.

Description: This paper summarizes the conversion status of US research and test reactors and estimates uranium densities needed to convert reactors with power levels 21 MW from HEU ({ge} 20% U-235) to LEU (<20% U-235) fuels. Detailed conversion studies for each reactor need to be completed in order to establish the feasibility of using LEU fuels.
Date: November 14, 1997
Creator: Matos, J. E.
Partner: UNT Libraries Government Documents Department
open access

Modeling the behavior of an earthquake base-isolated building.

Description: Protecting a structure against earthquake excitation by supporting it on laminated elastomeric bearings has become a widely accepted practice. The ability to perform accurate simulation of the system, including FEA of the bearings, would be desirable--especially for key installations. In this paper attempts to model the behavior of elastomeric earthquake bearings are outlined. Attention is focused on modeling highly-filled, low-modulus, high-damping elastomeric isolator systems; comparisons are… more
Date: November 26, 1997
Creator: Coveney, V. A.; Jamil, S.; Johnson, D. E.; Kulak, R. F. & Uras, R. A.
Partner: UNT Libraries Government Documents Department
open access

Architecture of the APS real-time orbit feedback system.

Description: The APS Real-Time Orbit Feedback System is designed to stabilize the orbit of the stored positron beam against low-frequency sources such as mechanical vibration and power supply ripple. A distributed array of digital signal processors is used to measure the orbit and compute corrections at a 1kHz rate. The system also provides extensive beam diagnostic tools. This paper describes the architectural aspects of the system and describes how the orbit correction algorithms are implemented.
Date: November 21, 1997
Creator: Carwardine, J. A. & Lenkszus, F. R.
Partner: UNT Libraries Government Documents Department
open access

A study of nitrogenation of a NdFe{sub 12-x}Mo{sub x} compound by in situ neutron powder diffraction.

Description: The effects on the crystal lattice of a NdFe{sub 12{minus}x}Mo{sub x}(x {approx_equal} 1.7) compound which contained {approximately}12 vol% of bcc-Fe were studied by neutron powder diffraction during controlled nitrogenation over the 25-600 C temperature range. The sample inside the furnace was connected to a closed volume of ultra-pure nitrogen gas while neutron data were collected over regular time intervals during sequential heating. Substantial nitrogen absorption occurred between 500 to 60… more
Date: November 18, 1997
Creator: Ding, Y.; Lin, J.; Loong, C.-K. & Short, S. M.
Partner: UNT Libraries Government Documents Department
open access

Design and fabrication of high density uranium dispersion fuels.

Description: Twelve different uranium alloys and compounds with uranium densities greater than 13.8 g/cc were fabricated into fuel plates. Sixty-four experimental fuel plates, referred to as microplates, with overall dimensions of 76.2 mm x 22.2 mm x 1.3 mm and elliptical fuel zone of nominal dimensions of 51 mm x 9.5 mm, began irradiation in the Advanced Test Reactor on August 23, 1997. The fuel test matrix consists of machined or comminuted (compositions are in weight%) U-10Mo,U-8Mo, U-6Mo, U-4Mo, U-9Nb-3… more
Date: November 5, 1997
Creator: Clark, C. R.; McGann, D. J.; Meyer, M. K.; Trybus, C. L. & Wiencek, T. C.
Partner: UNT Libraries Government Documents Department
open access

Top quark results from D-Zero

Description: This is a brief summary of D0's top quark measurements, including {sigma}{sub t{bar t}} and m{sub t} in the {ell} + jets and dilepton channels, {sigma}{sub t{bar t}} in the all jets channel, and the search for top disappearance via t {yields} bH{sup +}, H{sup +} {yields} {tau}{nu} or c{bar s}.
Date: November 1, 1997
Creator: Strovink, Mark
Partner: UNT Libraries Government Documents Department
open access

Equation of State measurements of hydrogen isotopes on Nova

Description: High intensity lasers can be used to perform measurements of materials at extremely high pressures if certain experimental issues can be overcome. We have addressed those issues and used the Nova laser to shock-compress liquid deuterium and obtain measurements of density and pressure on the principal Hugoniot at pressures from 300 kbar to more than 2 Mbar. The data are compared with a number of equation of state models. The data indicate that the effect of molecular dissociation of the deuteriu… more
Date: November 1, 1997
Creator: Collins, G. W., LLNL
Partner: UNT Libraries Government Documents Department
open access

Integrated demonstration of molten salt oxidation with salt recycle for mixed waste treatment

Description: Molten Salt Oxidation (MSO) is a thermal, nonflame process that has the inherent capability of completely destroying organic constituents of mixed wastes, hazardous wastes, and energetic materials while retaining inorganic and radioactive constituents in the salt. For this reason, MSO is considered a promising alternative to incineration for the treatment of a variety of organic wastes. Lawrence Livermore National Laboratory (LLNL) has prepared a facility and constructed an integrated pilot-sca… more
Date: November 1, 1997
Creator: Hsu, P.C.
Partner: UNT Libraries Government Documents Department
open access

Millisecond Burning of Confined Energetic Materials During Cookoff

Description: The response of a system containing an energetic material (EM) to an abnormal thermal environment is termed cookoff. To predict the violence of reaction of confined energetic materials during cookoff requires a description of the relevant physical processes that occur on time scales Ranging from days to submicroseconds. The time-to-ignition can be characterized accurately using heat transfer with chemistry and quasistatic mechanics. After ignition the energetic material deflagrates on a millise… more
Date: November 1, 1997
Creator: Schmitt, R. G. & Baer, T. A.
Partner: UNT Libraries Government Documents Department
open access

COLOR SUPERCONDUCTIVITY, INSTANTONS AND PARITY (NON?)-CONSERVATION AT HIGH BARYON DENSITY-VOLUME 5.

Description: This one day Riken BNL Research Center workshop was organized to follow-up on the rapidly developing theoretical work on color super-conductivity, instanton dynamics, and possible signatures of parity violation in strong interactions that was stimulated by the talk of Frank Wilczek during the Riken BNL September Symposium. The workshop was held on November 11, 1997 at the center with over 30 participants. The program consisted of four talks on theory in the morning followed by two talks in the … more
Date: November 11, 1997
Creator: Gyulassy, M.
Partner: UNT Libraries Government Documents Department
open access

Physics of advanced tokamaks

Description: Significant reductions in the size and cost of a fusion power plant core can be realized if simultaneous improvements in the energy replacement time, {tau}{sub E}, and the plasma pressure or beta, {beta}{sub T} = 2 {micro}{sub 0} <P>/B{sup 2} can be achieved in steady-state conditions with high self-driven, bootstrap current fraction. Significant recent progress has been made in experimentally achieving these high performance regimes and in developing a theoretical understanding of the underlyi… more
Date: November 1997
Creator: Taylor, T. S.
Partner: UNT Libraries Government Documents Department
open access

Measuring solar spectral and angle-of-incidence effects on photovoltaic modules and solar irradiance sensors

Description: Historically, two time-of-day dependent factors have complicated the characterization of photovoltaic module and array performance; namely, changes in the solar spectrum over the day and optical effects in the module that vary with the solar angle-of-incidence. This paper describes straightforward methods for directly measuring the effects of these two factors. Measured results for commercial modules, as well as for typical solar irradiance sensors (pyranometers) are provided. The empirical rel… more
Date: November 1, 1997
Creator: King, David L.; Kratochvil, Jay A. & Boyson, William E.
Partner: UNT Libraries Government Documents Department
open access

Temperature coefficients for PV modules and arrays: Measurement methods, difficulties, and results

Description: The term temperature coefficient has been applied to several different photovoltaic performance parameters, including voltage, current, and power. The procedures for measuring the coefficient(s) for modules and arrays are not yet standardized, and systematic influences are common in the test methods used to measure them. There are also misconceptions regarding their application. Yet, temperature coefficients, however obtained, play an important role in PV system design and sizing, where often t… more
Date: November 1, 1997
Creator: King, David L.; Kratochvil, Jay A. & Boyson, William E.
Partner: UNT Libraries Government Documents Department
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