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Compound-Nucleus Formation Following Direct Interactions to Highly-Excited Final States

Description: When direct reactions populate highly excited, unbound configurations in the residual nucleus, the nucleus may further evolve into a compound nucleus. Alternatively, the residual system may decay by emitting particles into the continuum. Understanding the relative weights of these two processes as a function of the angular momentum and parity deposited in the nucleus is important for the surrogate-reaction technique. A particularly interesting case is compound-nucleus formation via the (d, p) r… more
Date: February 5, 2008
Creator: Dietrich, F S
Partner: UNT Libraries Government Documents Department
open access

Non-magnetic compensation in ferromagnetic Ga1-xMnxAs and Ga1-xMnxP synthesized by ion implantation and pulsed-laser melting

Description: The electronic and magnetic effects of intentional compensation with non-magnetic donors are investigated in the ferromagnetic semiconductors Ga1-xMnxAs and Ga1-xMnxP synthesized using ion implantation and pulsed-laser melting (II-PLM). It is demonstrated that compensation with non-magnetic donors and MnI have similarqualitative effects on materials properties. With compensation TC decreases, resistivity increases, and stronger magnetoresistance and anomalous Hall effect attributed to skew scat… more
Date: February 5, 2008
Creator: Scarpulla, M. A.; Stone, P. R.; Sharp, I. D.; Haller, E. E.; Dubon, O. D.; Beeman, J. W. et al.
Partner: UNT Libraries Government Documents Department
open access

Supersymmetry in Elementary Particle Physics

Description: These lectures give a general introduction to supersymmetry, emphasizing its application to models of elementary particle physics at the 100 GeV energy scale. I discuss the following topics: the construction of supersymmetric Lagrangians with scalars, fermions, and gauge bosons, the structure and mass spectrum of the Minimal Supersymmetric Standard Model (MSSM), the measurement of the parameters of the MSSM at high-energy colliders, and the solutions that the MSSM gives to the problems of elect… more
Date: February 5, 2008
Creator: Peskin, Michael E.
Partner: UNT Libraries Government Documents Department
open access

Evaluation of radioactive background rejection in 76Ge neutrino-lessdouble-beta decay experiments using a highly segmented HPGe detector

Description: A highly segmented coaxial HPGe detector was operated in a low background counting facility for over 1 year to experimentally evaluate possible segmentation strategies for the proposed Majorana neutrino-less double-beta decay experiment. Segmentation schemes were evaluated on their ability to reject multi-segment events while retaining single-segment events. To quantify a segmentation scheme's acceptance efficiency the percentage of peak area due to single segment events was calculated for peak… more
Date: February 5, 2007
Creator: Chan, Yuen-Dat; Campbell, D. B.; Vetter, K.; Henning, R.; Lesko, K.; Chan, Y. D. et al.
Partner: UNT Libraries Government Documents Department
open access

Nuclear World Order and Nonproliferation

Description: The decision by India and Pakistan in May 1998 to conduct nuclear weapon tests and declare themselves as nuclear weapon states challenged South Asian regional stability calculations, US nonproliferation policy, and prevailing assumptions about international security. A decade later, the effects of those tests are still being felt and policies are still adjusting to the changed global conditions. This paper will consider non- and counter-proliferation policy options for the United States and Pak… more
Date: February 5, 2007
Creator: Joeck, N
Partner: UNT Libraries Government Documents Department
open access

Modeling of High Precision Neutron Nonelastic Cross Sections

Description: A new method has been applied to the determination of neutron nonelastic cross sections for iron {sup 56}Fe and lead {sup 208}Pb for energies between 5 and 26 MeV. These data have estimated errors of only a few percent and do not suffer from the ambiguities encountered in earlier nonelastic data. We attempt to fit these high precision data using both a semiclassical single phase shift model (nuclear Ramsauer model) as well as a recent global optical model that well reproduces a wide body of neu… more
Date: February 5, 2007
Creator: Dietrich, F. S.; Anderson, J. D.; Bauer, R. W.; Grimes, S. M. & McNabb, D. P.
Partner: UNT Libraries Government Documents Department
open access

Predamage threshold electron emission from insulator and semiconductor surfaces

Description: Predamage electron emission shows a dependence on fluence, bandgap and wavelength consistent with multiphoton excitation across the bandgap and inconsistent with avalanche ionization and thermionic emission models. The electron emission scales with pulselength as 1/..sqrt..T. 6 references, 8 figures, 1 table.
Date: February 5, 1985
Creator: Siekhaus, W.J.; Kinney, J.H. & Milam, D.
Partner: UNT Libraries Government Documents Department
open access

Adapting high-resolution speckle imaging to moving targets and platforms

Description: High-resolution surveillance imaging with apertures greater than a few inches over horizontal or slant paths at optical or infrared wavelengths will typically be limited by atmospheric aberrations. With static targets and static platforms, we have previously demonstrated near-diffraction limited imaging of various targets including personnel and vehicles over horizontal and slant paths ranging from less than a kilometer to many tens of kilometers using adaptations to bispectral speckle imaging … more
Date: February 5, 2004
Creator: Carrano, C J & Brase, J M
Partner: UNT Libraries Government Documents Department
open access

Statistical Stability and Time-Reversal Imgaing in Random Media

Description: Localization of targets imbedded in a heterogeneous background medium is a common problem in seismic, ultrasonic, and electromagnetic imaging problems. The best imaging techniques make direct use of the eigenfunctions and eigenvalues of the array response matrix, as recent work on time-reversal acoustics has shown. Of the various imaging functionals studied, one that is representative of a preferred class is a time-domain generalization of MUSIC (MUltiple Signal Classification), which is a well… more
Date: February 5, 2002
Creator: Berryman, J; Borcea, L; Papanicolaou, G & Tsogka, C
Partner: UNT Libraries Government Documents Department
open access

Effect of Small Variation in the Composition of Plates and Weld Filler Wires on the General Corrosion Rate of Ni-Cr-Mo Alloys

Description: The ASTM standard B 575 provides the requirements for the chemical composition of Nickel-Chromium-Molybdenum (Ni-Cr-Mo) alloys such as Alloy 22 (N06022) and Alloy 686 (N06686). The compositions of each element are given in a range. For example, the content of Mo is specified from 12.5 to 14.5 weight percent for Alloy 22 and from 15.0 to 17.0 weight percent for Alloy 686. It was important to determine how the corrosion rate of welded plates of Alloy 22 using Alloy 686 weld filler metal would cha… more
Date: February 5, 2005
Creator: Fix, David V.; Estill, John C. & Rebak, Raúl B.
Partner: UNT Libraries Government Documents Department
open access

Immobilization of uranium and plutonium into borobasalt, pyroxene and andradite mineral-like compositions

Description: The immobilization of plutonium-containing wastes into stable solid compositions is one of the problems to be solved in the disposal of radioactive wastes. Research efforts on the selection, preparation with the use of the cold crucible induction melter (CCIM) technology, and investigation of materials that are most suitable for immobilizing plutonium-containing wastes of different origin have been carried out at the All-Russian Scientific Research Institute of Inorganic Materials (VNIINM) and … more
Date: February 5, 2001
Creator: Matyunin, Y I; Jardine, L J & Yudintsev, S V
Partner: UNT Libraries Government Documents Department
open access

Stopping and Baryon Transport in Heavy Ion Reactions.

Description: In this report I will give an experimental overview on nuclear stopping in hadron collisions, and relate observations to understanding of baryon transport. Baryon number transport is not only evidenced via net-proton distributions but also by the enhancement of strange baryons near mid-rapidity. Although the focus is on high-energy data obtained from pp and heavy ions from RHIC, relevant data from SPS and ISR will be considered. A discussion how the available data at higher energy relates and g… more
Date: February 5, 2005
Creator: Videbaek, F.
Partner: UNT Libraries Government Documents Department
open access

Laser Systems for Orbital Debris Removal

Description: The use of a ground based laser for space debris cleaning was investigated by the ORION project in 1996. Since that study the greatest technological advance in the development of high energy pulsed laser systems has taken place within the NIF project at LLNL. The proposed next laser system to follow the NIF at LLNL will be a high rep rate version of the NIF based on diode-pumping rather than flashlamp excitation; the so called 'LIFE' laser system. Because a single 'LIFE' beamline could be built… more
Date: February 5, 2010
Creator: Rubenchik, A M; Barty, C P; Beach, R J; Erlandson, A C & Caird, J A
Partner: UNT Libraries Government Documents Department
open access

NEUTRON MULTIPLICITY AND ACTIVE WELL NEUTRON COINCIDENCE VERIFICATION MEASUREMENTS PERFORMED FOR MARCH 2009 SEMI-ANNUAL DOE INVENTORY

Description: The Analytical Development (AD) Section field nuclear measurement group performed six 'best available technique' verification measurements to satisfy a DOE requirement instituted for the March 2009 semi-annual inventory. The requirement of (1) yielded the need for SRNL Research Operations Department Material Control & Accountability (MC&A) group to measure the Pu content of five items and the highly enrich uranium (HEU) content of two. No 14Q-qualified measurement equipment was available to… more
Date: February 5, 2010
Creator: Dewberry, R.; Ayers, J.; Tietze, F. & Klapper, K.
Partner: UNT Libraries Government Documents Department
open access

SOLAR PUMPED LASER MICROTHRUSTER

Description: The development of microsatellites requires the development of engines to modify their orbit. It is natural to use solar energy to drive such engines. For an unlimited energy source the optimal thruster must use a minimal amount of expendable material to minimize launch costs. This requires the ejected material to have the maximal velocity and, hence, the ejected atoms must be as light as possible and be ejected by as high an energy density source as possible. Such a propulsion can be induced b… more
Date: February 5, 2010
Creator: Rubenchik, A M; Beach, R; Dawson, J & Siders, C W
Partner: UNT Libraries Government Documents Department
open access

The Search for Milky Way Halo Substructure WIMP Annihilations Using the GLAST LAT

Description: The GLAST LAT Collaboration is one among several experimental groups, covering a wide range of approaches, pursuing the search for the nature of dark matter. The GLAST LAT has the unique ability to find new sources of high energy gamma radiation emanating directly from WIMP annihilations in situ in the universe. Using it's wide band spectral and full sky spatial capabilities, the GLAST LAT can form ''images'' in high energy gamma-rays of dark matter substructures in the gamma-ray sky. We descri… more
Date: February 5, 2007
Creator: Wai, Larry
Partner: UNT Libraries Government Documents Department
open access

Impact of Small Chemistry Variations in Plate and Weld Filler Metal on the Corrosion Performance of Ni-Cr-Mo Alloys

Description: The ASTM standard B 575 provides the requirements for the chemical composition of Nickel-Chromium-Molybdenum (Ni-Cr-Mo) alloys such as Alloy 22 (N06022) and Alloy 686 (N06686). The compositions of each element are given in a range. For example, the content of Mo is specified from 12.5 to 14.5 weight percent for Alloy 22 and from 15.0 to 17.0 weight percent for Alloy 686. It was important to determine how the corrosion rate of welded plates of Alloy 22 using Alloy 686 weld filler metal would cha… more
Date: February 5, 2006
Creator: Fix, D V & Rebak, R B
Partner: UNT Libraries Government Documents Department
open access

Long-Term Corrosion Behavior of Alloy 22 in 5 M CaCl2 at 120?C

Description: In conditions where tight crevices exist in hot chloride containing solutions Alloy 22 may suffer crevice corrosion. The occurrence (or not) of crevice corrosion in a given environment (e.g. salt concentration and temperature), is governed by the values of the critical potential (E{sub crit}) for crevice corrosion and the corrosion potential (E{sub corr}). This paper discusses the evolution of E{sub corr} and corrosion rate (CR) of creviced Alloy 22 specimens in 5 M calcium chloride (CaCl{sub 2… more
Date: February 5, 2006
Creator: Estill, J. C.; Hust, G. A.; Evans, K. J.; Stuart, M. L. & Rebak, R. B.
Partner: UNT Libraries Government Documents Department
open access

Effect of Chemistry Variations in Plate and Weld Filler Metal on the Corrosion Performance of Ni-Cr-Mo Alloys

Description: The ASTM standard B 575 provides the requirements for the chemical composition of Nickel-Chromium-Molybdenum (Ni-Cr-Mo) alloys such as Alloy 22 (N06022) and Alloy 686 (N06686). The compositions of each element are given in a range. For example, the content of Mo is specified from 12.5 to 14.5 weight percent for Alloy 22 and from 15.0 to 17.0 weight percent for Alloy 686. It was important to determine how the corrosion rate of welded plates of Alloy 22 using Alloy 686 weld filler metal would cha… more
Date: February 5, 2006
Creator: Fix, D V & Rebak, R B
Partner: UNT Libraries Government Documents Department
open access

Electrochemical Testing of Gas Tungsten Arc Welded and Reduced Pressure Electron Beam Welded Alloy 22

Description: Alloy 22 (N06022) is the material selected for the fabrication of the outer shell of the nuclear waste containers for the Yucca Mountain high-level nuclear waste repository site. A key technical issue in the waste package program has been the integrity of the container weld joints. The currently selected welding process for fabricating and sealing the containers is the traditional gas tungsten arc welding (GTAW) or TIG method. An appealing faster alternative technique is reduced pressure electr… more
Date: February 5, 2006
Creator: Day, S. D.; Wong, F. G.; Gordon, S. R.; Wong, L. L. & Rebak, R. B.
Partner: UNT Libraries Government Documents Department
open access

Finding Text Information in the Ocean of Electronic Documents

Description: Information management in natural resources has become an overwhelming task. A massive amount of electronic documents and data is now available for creating informed decisions. The problem is finding the relevant information to support the decision-making process. Determining gaps in knowledge in order to propose new studies or to determine which proposals to fund for maximum potential is a time-consuming and difficult task. Additionally, available data stores are increasing in complexity; they… more
Date: February 5, 2003
Creator: Medvick, Patricia A. & Calapristi, Augustin J.
Partner: UNT Libraries Government Documents Department
open access

Dark Matter Searches With GLAST

Description: Indirect detection of particle dark matter relies upon pair annihilation of Weakly Interaction Massive Particles (WIMPs), which is complementary to the well known techniques of direct detection (WIMP-nucleus scattering) and collider production (WIMP pair production). Pair annihilation of WIMPs results in the production of gamma-rays, neutrinos, and anti-matter. Of the various experiments sensitive to indirect detection of dark matter, the Gamma-ray Large Area Space Telescope (GLAST) may play th… more
Date: February 5, 2007
Creator: Wai, Lawrence & Nuss, E.
Partner: UNT Libraries Government Documents Department
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