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Effects of radiation on laser diodes.

Description: The effects of ionizing and neutron radiation on the characteristics and performance of laser diodes are reviewed, and the formation mechanisms for nonradiative recombination centers, the primary type of radiation damage in laser diodes, are discussed. Additional topics include the detrimental effects of aluminum in the active (lasing) volume, the transient effects of high-dose-rate pulses of ionizing radiation, and a summary of ways to improve the radiation hardness of laser diodes. Radiation … more
Date: September 1, 2004
Creator: Phifer, Carol Celeste
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Severe plastic deformation through adiabatic shear banding in Fe-C steels

Description: Severe plastic deformation is observed within adiabatic shear bands in iron-carbon steels. These shear bands form under high strain rate conditions, in excess of 1000 s{sup -1}, and strains in the order 5 or greater are commonly observed. Studies on shear band formation in a ultrahigh carbon steel (1.3%C) are described in the pearlitic condition. A hardness of 11.5 GPa (4600 MPa) is obtained within the band. A mechanism is described to explain the high strength based on phase transformation to … more
Date: December 1, 2004
Creator: Lesuer, D; Syn, C & Sherby, O
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Low-Temperature Aging Mechanisms in U-6wt% Nb

Description: Phase stability and aging mechanisms in a water-quenched (WQ) U-6wt% Nb (U-14at% Nb) alloy artificially aged at 200 C and naturally aged at ambient temperature for 15 years have been investigated and studied using Vickers-hardness measurement, X-ray diffraction (XRD) analysis, and transmission electron microscopy (TEM) techniques. Age hardening/softening phenomenon is recorded from the artificially aged samples based upon the microhardness measurement. The age hardening can be readily rationali… more
Date: December 7, 2004
Creator: Hsiung, L L
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

RESULTS OF CHARACTERIZATION TESTS OF THE SURFACES OF A COMMERCIALLY CARBURIZED AUSTENITIC STAINLESS STEEL

Description: A commercial surface carburization treatment that shows promise for hardening the surfaces of the stainless steel target vessel of the Spallation Neutron Source against cavitation erosion and pitting caused by the action of pulsed pressure waves in the liquid mercury target has been investigated. To verify promotional claims for the treatment and to uncover any factors that might be of concern for the integrity of a carburized target vessel, some characterization tests of the nature of the surf… more
Date: January 7, 2004
Creator: Farrell, K
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Pilot-Scale Testing of a Rotary Microfilter with Irradiated Filter Disks and Simulated SRS Waste

Description: The processing rate of the Actinide Removal Project (ARP) is limited by the flow rate of the solid-liquid separation process. If the Department of Energy, DOE, could identify and develop a solid- liquid separation technology with a higher filter flux, they could increase the throughput of the Actinide Removal Project and complete treating that fraction of the waste stream in a shorter time, with a significant reduction in life-cycle cost. Savannah River Technology Center personnel identified th… more
Date: January 20, 2004
Creator: POIRIER, MICHAELR.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Evaluation of Roof Bolting Requirements Based on In-Mine Bolter Drilling Progress Report

Description: In this quarter, the field, theoretical and programming works have been performed toward achieving the research goals set in the proposal. The main accomplishments in this quarter included: (1) two more sets of field tests have been conducted in an underground coal mine, (2) optimization studies of the control parameters have been conducted, (3) method to use torque to thrust ratio as indicator of rock relative hardness has also been explored, and (3) about 97% of the development work for the r… more
Date: September 15, 2004
Creator: Peng, Syd S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Development of Appropriate Spot Welding Practice for Advanced High Strength Steels (TRP 0114)

Description: This program evaluated the effects of common manufacturing variables on spike-tempering effectiveness. The investigation used design-of-experiment (DOE) techniques, and examined both dual-phase and martensitic grades of high-strength steels (HSS). The specific grades chosen for this project were: Dual-phase (DP) 600, galvannealed (GA), 1.55 mm (DP) 600; Dual-phase (DP) 980 (uncoated), 1.55 mm (DP) 980; and Martensitic (M) 1300, 1.55 mm (M) 1300. Common manufacturing conditions of interest inclu… more
Date: September 17, 2004
Creator: Girvin, Brian; Peterson, Warren & Gould, Jerry
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Evaluation of Roof Bolting Requirements Based on In-Mine Bolter Drilling Progress Report

Description: A one-year non-cost extension has been granted for this project. In this quarter, the field, theoretical and programming works have been performed toward achieving the research goals set in the proposal. The main accomplishments in this quarter included: (1) laboratory tests have been conducted, (2) with the added trendline analysis method, the accuracy of the data interpretation methodology will be improved and the interfaces and voids can be more reliably detected, (3) method to use torque to… more
Date: April 15, 2004
Creator: Peng, Syd S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Radiation damage studies for the D0 silicon detector

Description: We report on irradiation studies performed on spare production silicon detector modules for the current D0 silicon detector. The lifetime expectations due to radiation damage effects of the existing silicon detector are reviewed. A new upgrade project was started with the goal of a complete replacement of the existing silicon detector. In that context, several investigations on the radiation hardness of new prototype silicon microstrip detectors were carried out. The irradiation on different de… more
Date: January 1, 2004
Creator: Lehner, F. & U., /Zurich
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Synthesis and Thermal Stability of Amorphous Be-B-X Alloy Coatings

Description: Amorphous Be-B-X alloys are vapor deposited as coatings. The microstructure and hardness of the Be-B-X coatings are examined using transmission electron microscopy and nanoindentation, respectively. Whereas a Be-B-2.5 at.% Cu amorphous coating is found to crystallize to a cubic Be-33 at.% B phase at 673 K, a coating of Be-B-1.8 at.% Fe-0.4 at.% Cr-0.3 at.% Co does not crystallize until at a higher temperature of 748 K. The hardness of the amorphous Be-B-X coating increases with B content but is… more
Date: October 14, 2004
Creator: Jankowski, Alan Frederic; Wall, M. A. & Nieh, T. G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Measurement of charged particle multiplicities in gluon and quark jets in proton anti-proton collisions at s**(1/2) = 1.8-TeV

Description: The authors report the first model independent measurement of charged particle multiplicities in quark and gluon jets, N{sub q} and N{sub g}, produced at the Tevatron in p{bar p} collisions with center-of-mass energy 1.8 TeV and recorded by the Collider Detector at Fermilab. The measurements are made for jets with average energies 41 and 53 GeV by counting charged particle tracks in cones with opening angle of {theta}{sub c} = 0.28, 0.36, and 0.47 rad around the jet axis. The corresponding jet … more
Date: July 1, 2004
Creator: Acosta, D.; Affolder, Anthony A.; Albrow, M. G.; Ambrose, D.; Amidei, D.; Anikeev, K. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Design of an upgraded D0 silicon microstrip tracker for Run IIb at the Tevatron

Description: The D0 collaboration planned to upgrade the Silicon Tracker to withstand the radiation dose corresponding to above 2 fb{sup -1} of data. This new detector was designed to be functional up to at least 15 fb{sup -1}. The authors report on the design of the new Silicon Tracker with details of the innermost layer.
Date: January 1, 2004
Creator: Hanagaki, K.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Microstructural Origins of Dynamic Fracture in Ductile Metals

Description: Dynamic fracture is a material failure process at high strain-rates. Here, we limit our discussion to spallation fracture during shock wave loading. When a compressive shock wave reflects from a free surface, internal states of tension are created. If this tension exceeds the rupture strength of the material, it fails by nucleating and growing microscopic voids in ductile metals and cracks in brittle solids. This effect, known as spallation, was reported by Hopkinson in 1872 [1]. Rinehart and P… more
Date: February 18, 2004
Creator: Belak, J; Cazamias, J U; Fivel, M; Haupt, D; Kinney, J H; Kumar, M et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Monolithic Nanocrystalline Au Fabricated by the Compaction of Nanoscale Foam

Description: We describe a two-step dealloying/compaction process to produce nanocrystalline Au. First, nanocrystalline/nanoporous Au foam is synthesized by electrochemically-driven dealloying. The resulting Au foams exhibit porosities of 60 and 70% with pore sizes of {approx} 40 and 100 nm, respectively, and a typical grain size of <50 nm. Second, the nanoporous foams are fully compacted to produce nanocrystalline monolithic Au. The compacted Au was characterized by TEM and X-ray diffraction and tested … more
Date: July 28, 2004
Creator: Hodge, A. M.; Biener, J.; Hsiung, L. M.; Hamza, A. V. & Satcher, J. H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department

Development of chromium-tungsten alloys

Description: Cr alloys containing 0-30 weight % W were investigated for their high temperature strength and oxidation resistance. These experimental alloys are intended for use in elevated temperature applications. Alloys were melted in a water-cooled, copper-hearth arc furnace. Microstructure of the alloys was studied using X-ray diffraction, scanning electron microscopy, and light microscopy. Meyer and Vickers hardness tests were utilized for measuring room temperature strength. A hot hardness tester with… more
Date: March 1, 2004
Creator: Dogan, Omer N.; Alman, David E. & Hawk, Jeffrey A.
Item Type: Refine your search to only Presentation
Partner: UNT Libraries Government Documents Department
open access

Experimental Evidence of the Role of Intericosahedral Chains in the Hardness of Boron Carbide Films Deposited by Sputtering

Description: The relationship between structure and mechanical properties of sputter-deposited boron carbide films was investigated. Changes in the structure induced by annealing were characterized in terms of chemical composition, chemical bonding and concentrations of defects and of trapped impurities. The creation of new intericosahedral chains for higher annealing temperatures was revealed by infrared and Raman measurements, and the intensity of the infrared band at 1500 cm{sup -1} was found to be relat… more
Date: January 7, 2004
Creator: Nastasi, M.; Asoka-Kumar, P.; Jenei, Z.; Jacobsohn, L. G.; Averitt, R. D.; Wetteland, C. J. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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