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Perspectives in the theory of nuclear collective motion

Description: This report discusses three different subjects. The first is the development of a generalized version of the VMI (variable moment of inertia) model that ties it to the original form of the IBM (interacting boson model) and provides a possibility of fitting vibrational spectra with generalized vibrational formulas. The second is a suggestion for fitting band crossing calculations of the phenomenological type more completely than has hitherto been done into the framework of the VMI method. The th… more
Date: March 13, 1980
Creator: Klein, A.
Partner: UNT Libraries Government Documents Department
open access

Hyperfine Quenching of the 2s2p 3P0 State of Berylliumlike Ions

Description: The hyperfine-induced 2s2p {sup 3}P{sub 0}-2s{sup 2} {sup 1}S{sub 0} transition rate for Be-like {sup 47}Ti{sup 18+} was recently measured in a storage-ring experiment by Schippers et al. [Phys. Rev. Lett. 98, 033001 (2007)]. The measured value of 0.56(3) s{sup -1} is almost 60% larger than the theoretical value of 0.356 s{sup -1} from a multiconfiguration Dirac-Fock calculation by Marques et al. [Phys. Rev. A 47, 929 (1993)]. In this work, we use a large-scale relativistic configuration-intera… more
Date: March 13, 2008
Creator: Cheng, K T; Chen, M H & Johnson, W R
Partner: UNT Libraries Government Documents Department
open access

Nanofiltration of Electrolyte Solutions by Sub-2nm Carbon Nanotube Membranes

Description: Both MD simulations and experimental studies have shown that liquid and gas flow through carbon nanotubes with nanometer size diameter is exceptionally fast. For applications in separation technology, selectivity is required together with fast flow. In this work, we use pressure-driven filtration experiments to study ion exclusion in silicon nitride/sub-2-nm CNT composite membranes as a function of solution ionic strength, pH, and ion valence. We show that carbon nanotube membranes exhibit sign… more
Date: March 13, 2008
Creator: Fornasiero, F.; Park, H. G.; Holt, J. K.; Stadermann, M.; Kim, S.; In, J. B. et al.
Partner: UNT Libraries Government Documents Department
open access

Creep Testing Plastic-Bonded Explosives in Uni-axial Compression

Description: High fidelity measurements of time-dependent strain in the plastic-bonded explosives LX-17-1 and PBX 9502 have been performed under constant, uni-axial, compressive load using a custom designed apparatus. The apparatus uses a combination of extensometers and linear variable differential transformers coupled with a data acquisition system, thermal controls, and gravitational loading. The materials being tested consist of a crystalline explosive material mixed with a polymeric binder. The behavio… more
Date: March 13, 2008
Creator: Gagliardi, F J & Cunningham, B J
Partner: UNT Libraries Government Documents Department
open access

A multi-model assessment of pollution transport to the Arctic

Description: We examine the response of Arctic gas and aerosol concentrations to perturbations in pollutant emissions from Europe, East and South Asia, and North America using results from a coordinated model intercomparison. These sensitivities to regional emissions (mixing ratio change per unit emission) vary widely across models and species. Intermodel differences are systematic, however, so that the relative importance of different regions is robust. North America contributes the most to Arctic ozone po… more
Date: March 13, 2008
Creator: Shindell, D T; Chin, M; Dentener, F; Doherty, R M; Faluvegi, G; Fiore, A M et al.
Partner: UNT Libraries Government Documents Department
open access

Regulation of In Situ to Invasive Breast Carcinoma Transition

Description: The transition of ductal carcinoma in situ (DCIS) to invasive carcinoma is a key event in breast tumor progression that is poorly understood. Comparative molecular analysis of tumor epithelial cells from in situ and invasive tumors has failed to identify consistent tumor stage-specific differences. However, the myoepithelial cell layer, present only in DCIS, is a key distinguishing and diagnostic feature. To determine the contribution of non-epithelial cells to tumor progression, we analyzed th… more
Date: March 13, 2007
Creator: Hu, Min; Carroll, Danielle K.; Weremowicz, Stanislawa; Chen, Haiyan; Carrasco, Daniel; Richardson, Andrea et al.
Partner: UNT Libraries Government Documents Department
open access

Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and the Younger Dryas cooling

Description: A carbon-rich black layer, dating to ~;;12.9 ka, has been previously identified at ~;;50 Clovis-age sites across North America and appears contemporaneous with the abrupt onset of Younger Dryas (YD) cooling. The in situ bones of extinct Pleistocene megafauna, along with Clovis tool assemblages, occur below this black layer but not within or above it. Causes for the extinctions, YD cooling, and termination of Clovis culture have long been controversial. In this paper, we provide evidence for an … more
Date: March 13, 2007
Creator: Firestone, Richard B.; Firestone, R. B.; West, A.; Kennett, J. P.; Becker, L.; Bunch, T. E. et al.
Partner: UNT Libraries Government Documents Department
open access

Design and Formation of a Large, Tetrahedral, Metal-ligand Cluster Using 1,1'-Binaphthyl Ligands

Description: Many chemists have been fascinated with the development of discrete supramolecular structures that encapsulate guest molecules. These structures can be assembled through covalent or hydrogen bonds, electrostatic or metal-ligand interactions. These host structures have provided valuable insight into the forces involved in small molecule recognition. Our work has focused on the design and study of metal-ligand clusters of varying sizes. The naphthalene [M{sub 4}L{sub 6}]{sup 12-} cluster 1, shown… more
Date: March 13, 2008
Creator: Biros, Shannon M.; Yeh, Robert M. & Raymond, Kenneth N.
Partner: UNT Libraries Government Documents Department
open access

Long-term stability of organic carbon-stimulated chromatereduction in contaminated soils, and its relation to manganese redoxstatus

Description: In-situ reduction of toxic Cr(V1) to less hazardous Cr(II1)is becoming a popular strategy for remediating contaminated soils.However, the long term stability of reduced Cr remains to be understood,especially given the common presence of MnfIIIJV) oxides that reoxidizeCr(II1). This 4.6 year laboratory study tracked Cr and Mn redoxtransformations in soils contaminated with Cr(V1) which were then treatedwith different amounts of organic carbon (OC). Changes in Cr and Mnoxidation states within soil… more
Date: March 13, 2007
Creator: Tokunaga, Tetsu K.; Wan, Jiamin; Lanzirotti, Antonio; Sutton,Steve R.; Newville, Matthew & Rao, William
Partner: UNT Libraries Government Documents Department
open access

THE HYDROLYSIS AND OXIDATION BEHAVIOR OF LITHIUM BOROHYDRIDE AND MAGNESIUM HYDRIDE DETERMINED BY CALORIMETRY

Description: Lithium borohydride, magnesium hydride and the 2:1 'destabilized' ball milled mixtures (2LiBH{sub 4}:MgH{sub 2}) underwent liquid phase hydrolysis, gas phase hydrolysis and air oxidation reactions monitored by isothermal calorimetry. The experimentally determined heats of reaction and resulting products were compared with those theoretically predicted using thermodynamic databases. Results showed a discrepancy between the predicted and observed hydrolysis and oxidation products due to both kine… more
Date: March 13, 2008
Creator: Brinkman, K; Donald Anton, D; Joshua Gray, J & Bruce Hardy, B
Partner: UNT Libraries Government Documents Department
open access

Rupture-safe pressure transducers

Description: The design, fabrication and testing of a rupture-safe transducer for measuring gas pressures in a manned-area field environment are described. (LCL)
Date: March 13, 1979
Creator: Holten, D.C.
Partner: UNT Libraries Government Documents Department
open access

Introduction to the physics of ICF capsules

Description: Inertial Confinement Fusion is an approach to fusion which relies on the inertia of the fuel mass to provide confinement. To achieve conditions under which this confinement is sufficient for efficient thermonuclear burn, high gain ICF targets designed to be imploded directly by laser light. These capsules are generally a spherical shell which is filled with low density DT gas. The shell is composed of an outer region which forms the ablator and an inner region of frozen or liquid DT which forms… more
Date: March 13, 1989
Creator: Lindl, J.D.
Partner: UNT Libraries Government Documents Department
open access

Nuclear structure calculations for astrophysical applications

Description: Here we present calculated results on such diverse properties as nuclear energy levels, ground-state masses and shapes, {beta}-decay properties and fission-barrier heights. Our approach to these calculations is to use a unified theoretical framework within which the above properties can all be studied. The results are obtained in the macroscopic-microscopic approach in which a microscopic nuclear-structure single-particle model with extensions is combined with a macroscopic model, such as the l… more
Date: March 13, 1992
Creator: Moeller, P.; Kratz, K.L. (Mainz Univ. (Germany). Inst. fuer Kernchemie) & Nix, J.R. (Los Alamos National Lab., NM (United States))
Partner: UNT Libraries Government Documents Department
open access

Coulomb focusing and path'' interference of autoionizing electrons produced in 10 keV He sup + + He collisions

Description: Autoionizing electrons emitted following low energy ion-atom collisions may scatter significantly from the receding spectator ion's attractive Coulomb field. In such cases the observed electron intensity is focused'' in the direction of the scattering ion as a result of the effective compression of the emission solid angle. In addition, interference may occur between trajectories, corresponding to electrons scattering around opposite sides of the ion, which lead to the same final laboratory ele… more
Date: March 13, 1991
Creator: Swenson, J.K. (Lawrence Livermore National Lab., CA (USA)); Burgdoerfer, J. (Tennessee Univ., Knoxville, TN (USA)); Meyer, F.W.; Havener, C.C.; Gregory, D.C. & Stolterfoht, N. (Oak Ridge National Lab., TN (USA))
Partner: UNT Libraries Government Documents Department
open access

Physics of ignition for ICF capsules

Description: The implosion of an ICF capsule must accomplish both compression of the main fuel to several hundred grams per cubic centimeter and heating and compression of the central region of the fuel to ignition. This report discusses the physics of these conditions.
Date: March 13, 1989
Creator: Lindl, J.D.
Partner: UNT Libraries Government Documents Department
open access

Modeling of large aperture third harmonic frequency conversion of high power Nd:glass laser systems

Description: To provide high-energy, high-power beams at short wavelengths for inertial-confinement-fusion experiments, we routinely convert the 1.053-{mu}m output of the Nova, Nd:phosphate-glass, laser system to its third-harmonic wavelength. We describe performance and conversion efficiency modeling of the 3 {times} 3 arrays potassium-dihydrogen-phosphate crystal plates used for type II/type II phase-matched harmonic conversion of Nova 0.74-m diameter beams, and an alternate type I/type II phase-matching … more
Date: March 13, 1991
Creator: Henesian, M. A.; Wegner, P. J.; Speck, D. R.; Bibeau, C.; Ehrlich, R. B.; Laumann, C. W. et al.
Partner: UNT Libraries Government Documents Department
open access

Performance of a lead radiator, gas tube calorimeter

Description: Design and performance of a 4.2 radiation length lead-sandwich, gas tube hodoscope are discussed. The device, measuring 1 /times/ 2 m/sup 2/ in area and 12 cm in depth, was employed in Fermi National Accelerator Laboratory experiment 705. Multiple samplings of anode wires situated within three-walled aluminum tubes were used to generate an X coordinate; similarly, capacitively coupled copper-clad strips were ganged together to yield a Y coordinate. The results reviewed are based on an analysis … more
Date: March 13, 1989
Creator: Spiegel, L.; Arenton, M.; Chen, T. Y.; Conetti, S.; Cox, B.; Delchamps, S. W. et al.
Partner: UNT Libraries Government Documents Department
open access

Automated controlled-flow air infiltration measurement system

Description: An automated, controlled-flow air infiltration measurement system is described. This system measures total air flow, a volume per unit time, due to infiltration in a test space. Data analysis is discussed and the mixing problem is analyzed. Different modes of operating the system are considered: concentration decay, continuous flow in a single chamber; and continuous flow in a multichamber enclosure. Problems associated with the use of nitrous oxide as a tracer gas are described.
Date: March 13, 1978
Creator: Condon, P. E.; Grimsrud, D. T.; Sherman, M. H. & Kammerud, R. C.
Partner: UNT Libraries Government Documents Department
open access

Dynamics of heavy ion beams during longitudinal compression

Description: Heavy ion beams with initially uniform line charge density can be compressed longitudinally by an order of magnitude in such a way that the compressed beam has uniform line charge density and velocity-tilt profiles. There are no envelope mismatch oscillations during compression. Although the transverse temperature varies along the beam and also varies with time, no substantial longitudinal and transverse emittance growth has been observed. Scaling laws for beam radius and transport system param… more
Date: March 13, 1987
Creator: Ho, D.D.M.; Bangerter, R.O.; Lee, E.P.; Brandon, S. & Mark, J.W.K.
Partner: UNT Libraries Government Documents Department
open access

An overview of copper-laser development for isotope separation

Description: We have developed a copper-laser pumped dye-laser system that addresses all of the requirements for atomic vapor laser isotope separation. The requirement for high average power for the laser system has led to the development of copper-laser chains with injection-locked oscillators and multihundred-watt amplifiers. By continuously operating the Laser Demonstration Facility, we gain valuable data for further upgrade and optimization.
Date: March 13, 1987
Creator: Warner, B.E.
Partner: UNT Libraries Government Documents Department
open access

Nuclear structure calculations for astrophysical applications

Description: Here we present calculated results on such diverse properties as nuclear energy levels, ground-state masses and shapes, {beta}-decay properties and fission-barrier heights. Our approach to these calculations is to use a unified theoretical framework within which the above properties can all be studied. The results are obtained in the macroscopic-microscopic approach in which a microscopic nuclear-structure single-particle model with extensions is combined with a macroscopic model, such as the l… more
Date: March 13, 1992
Creator: Moeller, P.; Kratz, K. L. & Nix, J. R.
Partner: UNT Libraries Government Documents Department
open access

Beam Simulations for IRE and Driver - Status and Strategy

Description: The methods and codes employed in the U.S. Heavy Ion Fusion program to simulate the beams in an Integrated Research Experiments (IRE) facility and a fusion driver are presented in overview. A new family of models incorporating accelerating module impedance, multi-beam, and self-magnetic effects is described, and initial WARP3d particle simulations of beams using these models are presented. Finally, plans for streamlining the machine-design simulation sequence, and for simulating beam dynamics f… more
Date: March 13, 2001
Creator: Friedman, A; Grote, D P & Lee, E P
Partner: UNT Libraries Government Documents Department
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