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METALLURGY DIVISION QUARTERLY PROGRESS REPORT FOR PERIOD ENDING JANUARY 31, 1952

Description: Progress is reported on the following projects: Th alloy development, mechanical properties of Th, tensile properties and preferred orientation of Th, triple-dip slug canning, texture studies, fundumental studies of alloying, static cerrosion tests with low melting point alloys, dynamic corrosion testing of fluoride materials, mass transfer, structures of liquid Pb and liquid Bi, fabrication of tubular laminates for fuel elements, creep of Th, cone-arc welding, Homogeneous Reactor Experiment metallurgy, a low-temperature specimen holder for use with the highangle x-ray spectrometers, metallography of Zr and its alloys, automatic polishing machine, a fuel element manufacturing process for the direct-cycle aircraft reactor, and fabrication of fuel and control rod elements for the MTR. (L.T.W.)
Date: August 28, 1952
Creator: Bridges, W.H. ed.
Partner: UNT Libraries Government Documents Department

Arcing phenomena on CEBAF RF-windows at cryogenic temperatures

Description: During the CEBAF commissioning tests some of the superconducting cavities had light emitting discharges (arcing) which were observed in the guard vacuum space between a warm polymeric rf window and the cold ceramic rf window. A dedicated off-line test system was implemented to investigate the conditions under which arcing may occur and to gain some understanding of the mechanisms leading to this phenomenon through optical spectral analysis. This paper reports on the photoemission spectra observed during the dedicated tests on a single cell 1500 MHz niobium cavity with a ceramic window operated at 10 MV/m and 2 K. The light emission was detected using a spectrometer with an intensified photodiode array. The effect of moving the window away from the beam line using a waveguide elbow is reported. 12 refs.
Date: December 31, 1995
Creator: Powers, T.; Kneisel, P. & Allen, R.
Partner: UNT Libraries Government Documents Department

Investigation of High Voltage Breakdown and Arc Localization in RF Structures

Description: An effort is underway to improve the voltage standoff capabilities of ion cyclotron range of frequencies (ICRF) heating and current drive systems. One approach is to develop techniques for determining the location of an electrical breakdown (arc) when it occurs. A technique is described which uses a measurement of the reflection coefficient of a swept frequency signal to determine the arc location. The technique has several advantages including a requirement for only a small number of sensors and very simple data interpretation. In addition a test stand is described which will be used for studies of rf arc behavior. The device uses a quarter-wave resonator to produce voltages to 90 kV in the frequency range of 55-80 MHz.
Date: April 12, 1999
Creator: Bigelow, T.S.; Goulding, R.H. & Swain, D.W.
Partner: UNT Libraries Government Documents Department

AN INVESTIGATION OF SCALING OF ZIRCONIUM AT ELEVATED TEMPERATURES. Quarterly Status Report No. 17 for June 2, 1957 to September 2, 1957

Description: The variation of breakaway time, time for scale color change, and metal growth with temperature for arcand graphite melted Zr in oxygen are presented. (For preceding period see AECU-3529.) (auth)
Date: September 30, 1957
Creator: Probst, H.B.; Evans, E.B. & Baldwin, W.M. Jr.
Partner: UNT Libraries Government Documents Department

ARC CALCINATION OF THORIUM OXIDE

Description: An over-all description of the background material on the use of electrical arcs for heating of powders is presented as well as a summary of experimental studies on the arc calcination of thoria. Favorable results have been indicated both with heating thoria powder in an arc heated gas and with thoria formed into a consumable electrode. Use of a consumable electrode produces thoria particles 0.1 to 0.01 mu in diameter. It is recommended that additional electrodes be fabricated and further arc calcination tests be run to produce a quantity of product sufficient for evaluation. (auth)
Date: June 25, 1958
Creator: Johnsson, K.O.
Partner: UNT Libraries Government Documents Department

M-25, Butt Welds in Process Piping

Description: Metal-arc and inert-gas shielded tungsten-arc processes were compared for circumferential butt welding of austenitic stainless steel process pipe. Inert-gas tungsten-arc welding was superior to other techniques. (C.J.G.)
Date: July 10, 1958
Creator: Litman, A. P.
Partner: UNT Libraries Government Documents Department

Nitrogen Control in Electric Arc Furnace Steelmaking by DRI (TRP 0009)

Description: Nitrogen is difficult to remove in electric arc furnace (EAF) steelmaking, requiring the use of more energy in the oxygen steelmaking route to produce low-nitrogen steel. The objective of this work was to determine if the injection of directly reduced iron (DRI) fines into EAFs could reduce the nitrogen content by creating fine carbon monoxide bubbles that rinse nitrogen from the steel. The proposed work included physical and chemical characterization of DRI fines, pilot-scale injection into steel, and mathematical modeling to aid in scale-up of the process. Unfortunately, the pilot-scale injections were unsuccessful, but some full-scale data was obtained. Therefore, the original objectives were met, and presented in the form of recommendations to EAF steelmakers regarding: (1) The best composition and size of DRI fines to use; (2) The amount of DRI fines required to achieve a specific reduction in nitrogen content in the steel; and (3) The injection conditions. This information may be used by steelmakers in techno-economic assessments of the cost of reducing nitrogen with this technology.
Date: March 31, 2004
Creator: Irons, Gordon A.
Partner: UNT Libraries Government Documents Department

Gelcasting Polycrystalline Alumina

Description: OSRAM SYLVANIA INC. is a major U.S. manufacturer of high-intensity lighting. Among its products is the Lumalux TM line of high-pressure sodium vapor arc lamps, which are used for industrial, highway, and street lighting. The key to the performance of these lamps is the polycrystalline alumina (PCA) tube that is used to contain the plasma that is formed in the electric arc. That plasma consists of ionized sodium, mercury, and xenon vapors. The key attributes of the PCA tubes are their transparency ({approximately}97% total transmittance in the visible), their refractoriness (inner wall temperature can reach l2OOC), and their chemical resistance (sodium and mercury vapor are extremely corrosive). The current efficiency of the lamps is very high, up to 100 initial lumens per watt. (Compare incandescent lamps 10-20 lumens per watt, fluorescent lamps 25-90 lumens per watt.)
Date: January 1, 2000
Creator: Janney, M.A.; Zuk, K.J. & Wei, G.C.
Partner: UNT Libraries Government Documents Department

Carbon stripper foils used in the Los Alamos PSR

Description: Carbon stripper foils produced by the modified controlled ACDC arc discharge method (mCADAD) at the Institute for Nuclear Study have been tested and used for high current 800-MeV beam production in the Proton Storage Ring (PSR) since 1993. Two foils approximately 110 {mu}g/cm{sup 2} each are sandwiched together to produce an equivalent 220 {mu}g/cm{sup 2} foil. The foil sandwitch is supported by 4-5 {mu}m diameter carbon filters attached to an aluminum frame. These foils have survived as long as five months during PSR normal beam production of near 70 {mu}A average current on target. Typical life-times of other foils vary from seven to fourteen days with lower on-target average current. Beam loss data also indicate that these foils have slower shrinkage rates than standard foils. Equipment has been assembled and used to produce foils by the mCADAD method at Los Alamos. These foils will be tested during 1997 operation.
Date: December 1, 1997
Creator: Borden, M.J.; Plum, M.A. & Sugai, I.
Partner: UNT Libraries Government Documents Department

Laboratory experiments on arc deflection and instability

Description: This article describes experiments on arc deflection instability carried out during the past few years at the Princeton University Plasma Physics Laboratory (PPPL). The approach has been that of plasma physicists interested in arcs, but they believe these results may be useful to engineers who are responsible for controlling arc behavior in large electric steel furnaces.
Date: March 21, 2000
Creator: Zweben, S. & Karasik, M.
Partner: UNT Libraries Government Documents Department

Upgrade of a vacuum arc ion source using a strong pulsed magnetic field

Description: A pulsed magnetic field of up to 10 kG was incorporated into a vacuum arc ion source. The field was established by a small coil surrounding the arc discharge region, powered by either an additional power supply (capacitor bank) or by the arc power supply (arc current and coil current in series). This addition has led so a number of improvements in source performance: the mean charge state of the metal ions produced was enhanced by a factor of up to two, for 30 different cathode materials from carbon to bismuth; hybrid metal/gaseous ion beams could be generated when an additional gas (nitrogen, oxygen or argon) was admitted into the source, with gaseous ion fraction as high as 50%; triggering of the source could be done by a very long lifetime gaseous pre-discharge technique. We also report on the use of a wire mesh to stabilize the plasma emission surface at the extractor as a means for achieving a flat beam current characteristic as a function of extraction voltage.
Date: August 1, 1995
Creator: Oks, E. M.; Brown, I. G.; Dickinson, M. R. & MacGill, R. A.
Partner: UNT Libraries Government Documents Department

Vacuum arc ion sources - micro to macro

Description: Vacuum arc ion sources provide a convenient tool for the production of intense beams of metal ions. The sources are relatively easy to construct and they can produce beams from all of the solid metals as well as of compounds, alloys and mixtures. We have made a number of different kinds of such sources over the course of our development work at LBL in the past decade, from very small {open_quote}thumb-size{close_quote} versions to a very large one with 50-cm diameter extractor. Beam current ranges from a few milliamperes up to almost 10 amperes and extraction voltage from about 1 kV to 100 kV. Multicathode versions have been made so that one can switch between metal ion species simply and quickly. Most of the sources have been operated in a repetitively pulsed mode, and we`ve tested a dc version also. Here we outline some construction features of the array of vacuum arc ion sources that we`ve developed and used, and describe their performance and limitations.
Date: August 1995
Creator: MacGill, R. A.; Dickinson, M. R. & Brown, I. G.
Partner: UNT Libraries Government Documents Department

Plasma quench production of titanium from titanium tetrachloride

Description: This project, Plasma Quench Production of Titanium from Titanium Tetrachloride, centers on developing a technique for rapidly quenching the high temperature metal species and preventing back reactions with the halide. The quenching technique chosen uses the temperature drop produced in a converging/diverging supersonic nozzle. The rapid quench provided by this nozzle prevents the back reaction of the halide and metal. The nature of the process produces nanosized particles (10 to 100 nm). The powders are collected by cyclone separators, the hydrogen flared, and the acid scrubbed. Aluminum and titanium powders have been produced in the laboratory-scale device at 1 gram per hour. Efforts to date to scale up this process have not been successful.
Date: October 1, 1994
Creator: Sears, J. W.
Partner: UNT Libraries Government Documents Department

High power, high frequency, vacuum flange

Description: This invention is comprised of an improved waveguide flange is disclosed for high power operation that helps prevent arcs from being initiated at the junctions between waveguide sections. The flanges at the end of the waveguide sections have counterbores surrounding the waveguide tubes. When the sections are bolted together the counterbores form a groove that holds a fully annealed copper gasket. Each counterbore has a beveled step that is specially configured to insure the gasket forms a metal-to-metal vacuum seal without gaps or sharp edges. The resultant inner surface of the waveguide is smooth across the junctions between waveguide sections, and arcing is prevented.
Date: December 31, 1991
Creator: Felker, B. & McDaniel, M.
Partner: UNT Libraries Government Documents Department