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Large Exploding Wires-Correlation to Small Wires and Pause Time Versus Length Dependency

Description: The results of small exploding-wire studies were found to be capable of direct extrapolation to larger wires (an increase in cross-sectional area of 1500 to 1500 from the small wires). Copper wires up to 40 mils in diameter and iron wires to 62 mils in diameter were studied for use as fuses. in lengths up to 18 in. A dependency between pause time (the time between system current cut-off and current restrike) and wire length is described for several sizes of copper wires exploded with 16.5- and 49.5-kilojoule sources. The role of wire confinement is discussed in connection with establishment of the pause. (auth)
Date: May 1, 1959
Creator: Cnare, E. C. & Neilson, F. W.
Partner: UNT Libraries Government Documents Department

Linear stability of an accelerated wire array

Description: The linear stability of an array of a large number of thin wires is considered. The wires form a cylindrical surface which is accelerated towards the axis under the action of a current excited in the array by an external source. General equations governing stability of this system are derived and a complete classification of all the modes present in such a system is presented. In agreement with an earlier analysis by Felber and Rostoker, it is shown that there exist two types of modes: medial modes, in which the wires experience deformation in the rz plane, and lateral modes, in which only a purely azimuthal deformation is present. For a given axial wave number k, the maximum growth rate for medial perturbations corresponds to a mode in which all the wires move �in phase� (an analog of an axisymmetric mode for a continuous cylindrical shell), whereas for the lateral perturbations the maximum growth rate corresponds to the opposite displacements of the neighboring wires. Numerical analysis of a dispersion relation for a broad range of modes is presented: Some limiting cases are discussed. In particular, it is shown that a traditional k�� scaling holds until surprisingly high wave numbers, even exceeding the inverse inter- wire distance. In the limit of long-wavelength perturbations, a model of a continuous shell becomes valid; the presence of the wires manifests itself in this model by a strong anisotropy of electrical conductivity, high along the wires and vanishing across the wires. The resulting modes differ considerably from the modes of a thin perfectly conducting shell. In particular, a new mode of �zonal flows� is identified.
Date: October 15, 1998
Creator: Hammer, J H & Ryutov, D D
Partner: UNT Libraries Government Documents Department

Radiative Properties of High Wire Number Tungsten Arrays with Implosion Times up to 250 ns

Description: High wire number, 25-mm diameter tungsten wire arrays have been imploded on the 8-MA Saturn generator, operating in a long-pulse mode. By varying the mass load from 710 to 6140 ps/cm, implosion times of 130 to 250 ns have been obtained with implosion velocities of 50 to 25 cn-dys, respectively. These z-pinch implosions produced plasmas with millimeter diameters that radiated 600 to 800 kJ of x-rays, with powers of 20 to 49 TW; the corresponding pulse widths were 19 to 7.5 ns, with risetimes ranging from 6.5 to 4.0 ns. These powers and pulse widths are similar to those achieved with 50 ns implosion times on Saturn. Two-dimensional, radiation- magnetohydrodynamic calculations indicate that the imploding shells in these long implosion time experiments are comparable in width to those in the short pulse cases. This can only be due to lower initial perturbations. A heuristic wire array model suggests that the reduced perturbations, in the long pulse cases, may be due to the individual wire merger occurring well before the acceleration of the shell. The experiments and modeling suggest that 150 to 200 ns implosion time z-pinches could be employed for high-power, x-ray source applications.
Date: February 2, 1999
Creator: Beg, F.N.; Coverdale, C.A.; Deeney, C.; Douglas, M.R.; Haines, M.G.; Peterson, D.L. et al.
Partner: UNT Libraries Government Documents Department


Description: Second generation (2G) technologies to fabricate high-performance superconducting wires developed at the Oak Ridge National Laboratory (ORNL) were transferred to American Superconductor via this CRADA. In addition, co-development of technologies for over a decade was done to enable fabrication of commercial high-temperature superconducting (HTS) wires with high performance. The massive success of this CRADA has allowed American Superconductor Corporation (AMSC) to become a global leader in the fabrication of HTS wire and the technology is fully based on the Rolling Assisted Biaxially Textured Substrates (RABiTS) technology invented and developed at ORNL.
Date: October 23, 2012
Creator: Goyal, A. & Rupich, M. (American Superconductor Corp.)
Partner: UNT Libraries Government Documents Department

Wire brush fastening device

Description: A fastening device is provided which is a variation on the conventional nut and bolt. The bolt has a longitudinal axis and threading helically affixed thereon along the longitudinal axis. A nut having a bore extending therethrough is provided. The bore of the nut has a greater diameter than the diameter of the bolt so the bolt can extend through the bore. An array of wire bristles are affixed within the bore so as to form a brush. The wire bristles extend inwardly from the bore and are constructed and arranged of the correct size, length and stiffness to guide the bolt within the bore and to restrain the bolt within the bore as required. A variety of applications of the wire brush nut are disclosed, including a bolt capture device and a test rig apparatus.
Date: August 31, 1993
Creator: Meigs, R.A.
Partner: UNT Libraries Government Documents Department

Numerical simulation of fiber and wire array Z-pinches with Trac-II

Description: Trac-II is a two dimensional axisymmetric resistive MHD code. It simulates all three spatial components (r, z, &phi;) of the magnetic field and fluid velocity vectors, and the plasma is treated as a single fluid with two temperatures (T<sub>e</sub>,T<sub>i</sub>). In addition, it can optionally include a self-consistent external circuit. Recent modifications to the code include the addition of the 3-T radiation model, a 4-phase (solid-liquid-vapor-plasma) equation of state model (QEOS), a 4-phase electrical/thermal conductivity model, and an implicit solution of poloidal B<sub>z</sub>,B<sub>r</sub>) magnetic field diffusion. These changes permit a detailed study of fiber and wire array Z-pinches. Specifically, Trac-II is used to study the wire array Z-pinch at the PBFA-Z pulse power generator at Sandia National Laboratory. First, in 1-D we examine the behavior of a single wire in the Z-pinch. Then, using these results as initial radial conditions in 2-D, we investigate the dynamics of wire array configurations in the r-z and r-&theta; plane. In the r-z plane we examine the growth of the m=0 or ��sausage�� instability in single wires within the array. In the r-&theta; plane we examine the merging behavior between neighboring wires. Special emphasis is placed on trying to explain how instability growth affects the performance of the Z-pinch. Lastly, we introduce Trac-III, a 3-D MHD code, and illustrate the m=1 or �"kink" instability. We also discuss how Trac-III can be modified to simulate the wire array Z-pinch.
Date: September 1, 1998
Creator: Reisman, D
Partner: UNT Libraries Government Documents Department

Magnetoconductance of Independently Tunable Tunnel-Coupled Double Quantum Wires

Description: The authors report on their recent experimental studies of vertically-coupled quantum point contacts subject to in-plane magnetic fields. Using a novel flip-chip technique, mutually aligned split gates on both sides of a sub micron thick double quantum well heterostructure define a closely-coupled pair of ballistic one-dimensional (1D) constrictions. They observe quantized conductance steps due to each quantum well and demonstrate independent control of each ID constriction width. In addition, a novel magnetoconductance feature at {approximately}6 T is observed when a magnetic field is applied perpendicular to both the current and growth directions. This conductance dip is observed only when 1D subbands are populated in both the top and bottom constrictions. This data is consistent with a counting model whereby the number of subbands crossing the Fermi level changes with field due to the formation of an anticrossing in each pair of 1D subbands.
Date: July 13, 2000
Partner: UNT Libraries Government Documents Department

A New Form of Standard Resistance

Description: Report issued by the Bureau of Standards over new developments of electrical resistivity in manganin wire coils. The results of the developments are discussed. This report includes tables, illustrations, and photographs.
Date: October 1, 1908
Creator: Rosa, Edward B.
Partner: UNT Libraries Government Documents Department

Reaction Between Thin Gold Wires and Pb-Sn-In Solder (37.5%, 37.5%, 25%), Part B. The Axial Reaction Of Gold Wires Soldered To PbSnIn Solder Mounds, Its effect On Electrical Resistance And Physical Structure.

Description: Here we describe the gold-indium reaction along gold wires soldered at both ends. It begins with the combined radial/axial reaction in the vicinity of the solder mound as seen in metallurgical sections along the axis of the wire. We show that this combined radial/axial reaction has no effect on the resistance of the system, even though it shortens the length of the gold wire while converting it to gold indide. After this radial/axial reaction is complete, a purely axial reaction begins. For thin gold wires (i.e. 38.1 {micro}m diameter) the onset of that reaction is strongly correlated with the time at which the linear reaction model predicts the complete consumption of the gold wire inside the solder mounds. This purely axial reaction converts the whole wire rapidly to gold indide, and leads to substantial resistance changes and complete distortion of the wire between the solder mounds. The reaction product is AuIn{sub 2} everywhere, but both Sn and Pb also are identified everywhere on the surface by Electron Dispersive Spectroscopy.
Date: January 20, 2011
Creator: Siekhaus, W J
Partner: UNT Libraries Government Documents Department

Some comments on manganin wire pressure gauges

Description: A standard manganin wire pressure gage was examined by comparing it with a recently developed 0.01% CaF/sub 2/ capacitive pressure gage. The effects of the Bridgman water kick'' and intrinsic time constant are clearly shown, and the results punctuate the usual assertion that manganin wire gages are extremely difficult to use approaching the 0.1% level. (auth)
Date: January 1, 1973
Creator: Andeen, C.; Schuele, D. & Fontanella, J.
Partner: UNT Libraries Government Documents Department


Description: A manipulator or mechanical arm involves an upper and a lower arm, with a variable angle between them. Cables used to transmit motion and force from the upper to the lower arms pass over a pulley at the joint or elbow. A pulley, axiaily fixed with respect to the joint, imposes a change in length of the cable as the angle between the arms varies. Manipulation design requires a cable of constant length during this variation; this constant length may be achieved by guiding the center of the pulley along the proper path. Acceptable solutions were obtained in terms of variables such as the lengths of each arm, the radius of the pulley, and the angle between the arms. In one design the pulley center is moved along a straight line with respect to the lower arm, while in the other solution the pulley center is moved along a circular arc with respect to the upper amn. Practical and economical mechanisms based on these solutions were investigated for use in manipulator design. (auth)
Date: November 1, 1959
Creator: Grimson, J.H.
Partner: UNT Libraries Government Documents Department

Growth of Quantum Wires on Step-Bunched Substrate

Description: This proposal initiates a combined theoretical and experimental multidisciplinary research effort to explore a novel approach for growing metallic and magnetic nanowires on step-bunched semiconductor and dielectric substrates, and to lay the groundwork for understanding the growth mechanisms and the electronic, electrical, and magnetic properties of metallic and magnetic nanowires. The research will focus on four topics: (1) fundamental studies of step bunching and self-organization in a strained thin film for creating step-bunched substrates. (2) Interaction between metal adatoms (Al,Cu, and Ni) and semiconductor (Si and SiGe) and dielectric (CaF2) surface steps. (3) growth and characterization of metallic and magnetic nanowires on step-bunched templates. (4) fabrication of superlattices of nanowires by growing multilayer films. We propose to attack these problems at both a microscopic and macroscopic level, using state-of-the-art theoretical and experimental techniques. Multiscale (electronic-atomic-continuum) theories will be applied to investigate growth mechanisms of nanowires: mesoscopic modeling and simulation of step flow growth of strained thin films, in particular, step bunching and self-organization will be carried out within the framework of continuum linear elastic theory; atomistic calculation of interaction between metal adatoms and semiconductor and dielectric surface steps will be done by large-scale computations using first-principles total-energy methods. In parallel, thin films and nanowires will be grown by molecular beam epitaxy (MBE), and the resultant structure and morphology will be characterized at the atomic level up to micrometer range, using a combination of different surface/interface probes, including scanning tunneling microscopy (STM, atomic resolution), atomic force microscopy (AFM, nanometer resolution), low-energy electron microscopy (LEEM, micrometer resolution), reflectance high-energy electron diffraction (RHEED), and x-ray diffraction. Finally, the electronic, electrical, and magnetic properties of the thin films and nanowires will be explored by both theory and experiment.
Date: February 1, 2005
Creator: Liu, Feng
Partner: UNT Libraries Government Documents Department

Low-Cost Superconducting Wire for Wind Generators

Description: Advanced Research Projects Agency-Energy project sheet summarizing general information about the Rare Earth Alternatives in Critical Technologies (REACT) program including critical needs, innovation and advantages, impacts, and contact information. This sheet discusses a high-current superconducting wire as part of the "High Performance, Low Cost Superconducting Wires and Coils for High Power Wind Generators" project.
Date: May 25, 2012
Creator: University of Houston
Partner: UNT Libraries Government Documents Department

Test wire for high voltage power supply crowbar system

Description: The klystron microwave amplifier tubes used in the Low Energy Demonstration Accelerator (LEDA) and to be used in the Accelerator Production of Tritium (APT) plant have a strict upper limit on the amount of energy which can be safely dissipated within the klystron`s vacuum envelope during a high voltage arc. One way to prevent damage from occurring to the klystron microwave amplifier tube is through the use of a crowbar circuit which diverts the energy stored in the power supply filter capacitors from the tube arc. The crowbar circuit must be extremely reliable. To test the crowbar circuit, a wire that is designed to fuse when it absorbs a predetermined amount of energy is switched between the high voltage output terminals. The energy required to fuse the wire was investigated for a variety of circuits that simulated the power supply circuit. Techniques for calculating wire length and energy are presented along with verifying experimental data.
Date: September 1, 1997
Creator: Bradley, J.T. III & Collins, M.
Partner: UNT Libraries Government Documents Department

Bi-2212 and Bi-2223 wire development

Description: The results of innovative processing of Bi-2212 by isothermal melt processing and by controlled oxygen pressure cooling yield improved properties over the conventional routes. The addition of large grains of Ag has resulted in improved core/interface geometry and better performance in Bi-2212 and Bi-2223. A deformation processing study of Bi-2223 showed the effects of sheath material, relative core thickness, and reduction per pass on core/interface uniformity.
Date: December 1, 1995
Creator: Willis, J.O.; Ray, R.D. II & Holesinger, T.G.
Partner: UNT Libraries Government Documents Department

Department of Energy`s Wire Development Workshop - Superconductivity program for electric systems

Description: The 1996 High-Temperature Superconducting Wire Development Workshop was held on January 31--February 1 at the Crown Plaza Tampa Westshore in Tampa, Florida. The meeting was hosted by Tampa Electric Company and sponsored by the Department of Energy`s Superconductivity Program for Electric Systems. The meeting focused on recent high-temperature superconducting wire development activities in the Department of Energy`s Superconductivity Systems program. Tampa Electric`s Greg Ramon began the meeting by giving a perspective on the changes now occurring in the utility sector. Major program wire development accomplishments during the past year were then highlighted, particularly the world record achievements at Los Alamos and Oak Ridge National Laboratories. The meeting then focussed on three priority technical issues: thallium conductors; AC losses in HTS conductors; and coated conductors on textured substrates. Following in-depth presentations, working groups were formed in each technology area to discuss and critique the most important current research and development issues. The working groups identified research areas that have the potential for greatly enhancing the wire development effort. These areas are discussed in the summary reports from each of the working groups. This document is a compilation of the workshop proceedings including all general session presentations and summary reports from the working groups.
Date: June 1, 1996
Partner: UNT Libraries Government Documents Department