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in subjects: "37 Inorganic, Organic, Physical And Analytical Chemistry"  
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H2O Outgassing In and Its Effects on M9787 Silicone

Description: Temperature programmed desorption (TPD) was performed on M9787 silicone, Cab-O-Sil-M-7D (fumed) and Hi-Sil-233 (precipitated) silica particles that had been annealed to 460 K for 24 hours then exposed to different moisture levels. Our results suggest that moisture desorption and adsorption in M9787 can be approximated by the interaction of its silica contents (Cab-O-Sil-M-7D and Hi-Sil-233) with moisture. Our experimental data also reveal that, in general, as heat treated silica particles are e… more
Date: September 1, 2001
Creator: Dinh, L N; Schildbach, M A; McLean, W; Balazs, B; LeMay, J D & Balooch, M
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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What is a Shock Wave to an Explosive Molecule?

Description: An explosive molecule is a metastable chemical species that reacts exothermically given the correct stimulus. Impacting an explosive with a shock wave is a ''wake-up call'' or ''trigger'' which compresses and heats the molecule. The energy deposited by the shock wave must be distributed to the vibrational modes of the explosive molecule before chemical reaction can occur. If the shock pressure and temperature are high enough and last long enough, exothermic chemical decomposition can lead to th… more
Date: June 12, 2001
Creator: Tarver, Craig M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Metastable metallic hydrogen glass

Description: The quest for metallic hydrogen has been going on for over one hundred years. Before hydrogen was first condensed into a liquid in 1898, it was commonly thought that condensed hydrogen would be a metal, like the monatomic alkali metals below hydrogen in the first column of the Periodic Table. Instead, condensed hydrogen turned out to be transparent, like the diatomic insulating halogens in the seventh column of the Periodic Table. Wigner and Huntington predicted in 1935 that solid hydrogen at 0… more
Date: February 6, 2001
Creator: Nellis, W J
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Partner: UNT Libraries Government Documents Department
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Heats of Formation of Energetic Oxetane Monomers and Polymers

Description: Energetic oxetane polymers have shown promise as performance-enhancing ingredients in gun and missile propellants. In order to correctly predict the performance of energetic materials containing these polymers, it is important to have accurate, experimentally determined values for the polymer heats of formation ({Delta}H{sub f}). In support of a theoretical study on gun propellant performance, heats of combustion were experimentally determined for a series of oxetane polymers and monomers (see … more
Date: March 21, 2001
Creator: Schmidt, R D & Manser, G E
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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The Novel Synthesis of Silicon and Germanium Nanocrystallites

Description: Interest in the synthesis of semiconductor nanoparticles has been generated by their unusual optical and electronic properties arising from quantum confinement effects. We have synthesized silicon and germanium nanoclusters by reacting Zintl phase precursors with either silicon or germanium tetrachloride in various solvents. Strategies have been investigated to stabilize the surface, including reactions with RLi and MgBrR (R = alkyl). This synthetic method produces group IV nanocrystals with pa… more
Date: April 3, 2001
Creator: Kauzlarich, S. M.; Liu, Q.; Yin, S. C.; Lee, W. H. & Taylor, B.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Isentropic Compression of LX-04 on the Z Accelerator

Description: Three sets of LX-04 samples of 0.18 and 0.49 mm nominal thicknesses were all dynamically loaded by Sandia's Z-accelerator with a ramp compression wave with a 200 ns rise time and about 150 kb peak stress. The LX-04/lithium fluoride samples interface velocities were measured using VISAR's. Comparisons of experimental and computational results are given. Compression and release isentropes both show some reaction and kinetic behavior of the LX-04. Experiments were also performed on fine-grained TA… more
Date: June 7, 2001
Creator: Reisman, D B; Forbes, J W; Tarver, C M; Garcia, F; Cauble, R C; Hall, C A et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Electronic excitations and chemistry in Nitromethane and HMX

Description: The nature of electronic excitations in crystalline solid nitromethane under conditions of shock loading and static compression are examined. Density functional theory calculations are used to determine the crystal bandgap under hydrostatic stress, uniaxial strain, and shear strain. Bandgap lowering under uniaxial strain due to molecular defects and vacancies is considered. In all cases, the bandgap is not lowered enough to produce a significant population of excited states in the crystal. Prel… more
Date: June 19, 2001
Creator: Reed, E J; Manaa, M R; Joannopoulos, J D & Fried, L E
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Soap opera : polymer-surfactant interactions on thin film surfaces /

Description: Surfactants are macromolecules with unique properties. They commonly contain a polar head group with a nonpolar hydrocarbon chain. These properties allow surfactants to solubilize greases and other nonpolar molecules. One particular way that this is accomplished is through the formation of micelles. Micelles are formed at the critical micelle concentration (cmc), which varies depending upon the nature of the surfactant and also the media in which the surfactant resides. These micelles can take … more
Date: January 1, 2001
Creator: Ozer, B. H. (Byram H.); Johal, M. S. (Malkiat S.); Wang, H. L. (Hsing-Lin) & Robinson, J. M. (Jeanne M.)
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Topological excitations and second order transitions in 3D O(N) models

Description: I discuss several examples of critical phenomena in O(N) models where topological excitations play an important role at criticality. I focus particular attention on the O(2) model in 3D, where recent measurements of the vortex string length distribution in equilibrium suggest the existence of a quantitative picture of the critical behavior in terms of defects. The compatibility of this perspective with renormalization group predictions is examined.
Date: January 1, 2001
Creator: Bettencourt, L. (Luis M. A.)
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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KINETIC ANALYSIS OF HIGH-NITROGEN ENERGETIC MATERIALS USING MULTIVARIATE NONLINEAR REGRESSION

Description: New high-nitrogen energetic materials were synthesized by Hiskey and Naud. J. Opfermann reported a new tool for finding the probable model of the complex reactions using multivariate non-linear regression analysis of DSC and TGA data from several measurements run at different heating rates. This study is to take the kinetic parameters from the different steps and discover which reaction step is responsible for the runaway reaction by comparing predicted results from the Frank-Kamenetsckii equat… more
Date: January 1, 2001
Creator: Campbell, M. S. (Mary Stinecipher); Rabie, R. L. (Ronald L.); Diaz-Acosta, I. (Irina) & Pulay, P. (Peter)
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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High temperature oxidation of beryllium modified intermetallic compounds of the niobium-chromium system

Description: Intermetallic compounds based on the Laves phases NbCr2 and TiCr2 are of interest for high temperature applications. At temperatures where the high temperature strength and creep resistance of these compounds are excellent, their oxidation resistance is relatively poor. Beryllide compounds in the 3-Be, Ti-Be and Nb-Be systems (CrBe2, TiBel2, TiBez, NbBel2) on the other hand, exhibit excellent oxidation resistance even at temperaturets in excess of 1200' C, due to the formation of protective Be0… more
Date: January 1, 2001
Creator: Hanrahan, Robert J.; Peters, Maria I.; Cooley, Jason C.; Hults, William L.; Thoma, Dan J. & Chen, Katherine C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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The Evolution of High Temperature Gas Sensors.

Description: Gas sensor technology based on high temperature solid electrolytes is maturing rapidly. Recent advances in metal oxide catalysis and thin film materials science has enabled the design of new electrochemical sensors. We have demonstrated prototype amperometric oxygen sensors, nernstian potentiometric oxygen sensors that operate in high sulfur environments, and hydrocarbon and carbon monoxide sensing mixed potentials sensors. Many of these devices exhibit part per million sensitivities, response … more
Date: January 1, 2001
Creator: Garzon, F. H. (Fernando H.); Brosha, E. L. (Eric L.) & Mukundan, R. (Rangachary)
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Carbon Dioxide Sequestration by Direct Mineral Carbonation: Results from Recent Studies and Current Status

Description: Direct mineral carbonation has been investigated as a process to convert gaseous CO2 into a geologically stable, solid final form. The process utilizes a solution of sodium bicarbonate (NaHCO3), sodium chloride (NaCl), and water, mixed with a mineral reactant, such as olivine (Mg2SiO4) or serpentine [Mg3Si2O5(OH)4]. Carbon dioxide is dissolved into this slurry, by diffusion through the surface and gas dispersion within the aqueous phase. The process includes dissolution of the mineral and preci… more
Date: January 1, 2001
Creator: O'Connor, William K.; Dahlin, David C.; Nilsen, David N.; Rush, G.E.; Walters, Richard P. & Turner, Paul C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Corrosion behavior of rebar for intermittent cathodic protection of coastal bridges

Description: A number of reinforced concrete bridges on the Oregon coast are protected against chloride-induced corrosion damage by means of impressed current cathodic protection (ICCP). Thermal-sprayed Zn serves as the anode in these systems. Rebar in the concrete can remain passive and protected for some period of time after the CP system is turned off. The active-passive corrosion behavior of rebar in simulated pore solution (SPS) was investigated as a function of pH and Cl- concentration as part of a st… more
Date: February 1, 2001
Creator: Ziomek-Moroz, M. | Cramer, S.D. | Covino, B.S., Jr. | Bullard, S.J. | Holcomb, G.R. | Russell, J.H. | Windisch, Jr., C.F. (PNNL)
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Research status on the sequestration of carbon dioxide by direct aqueous mineral carbonation

Description: Direct aqueous mineral carbonation has been investigated as a process to convert gaseous CO2 into a geologically stable, solid final form. The process utilizes a solution of distilled water, or sodium bicarbonate (NaHCO3), sodium chloride (NaCl), and water, mixed with a mineral reactant, such as olivine (Mg2SiO4) or serpentine [Mg3Si2O5(OH)4]. Carbon dioxide is dissolved into this slurry, by diffusion through the surface and gas dispersion within the aqueous phase. The process includes dissolut… more
Date: January 1, 2001
Creator: O'Connor, William K.; Dahlin, David C.; Nilsen, David N.; Gerdemann, Stephen J.; Rush, Gilbert E.; Walters, Richard P. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Carbon dioxide sequestration by direct mineral carbonation: process mineralogy of feed and products

Description: Direct mineral carbonation has been investigated as a process to convert gaseous CO2 into a geologically stable final form. The process utilizes a slurry of water, with bicarbonate and salt additions, mixed with a mineral reactant, such as olivine (Mg2SiO4) or serpentine [Mg3Si2O5(OH)4]. Carbon dioxide is dissolved into this slurry, resulting in dissolution of the mineral and precipitation of magnesium carbonate (MgCO3). Optimum results have been achieved using heat pretreated serpentine feed m… more
Date: January 1, 2001
Creator: O'Connor, William K.; Dahlin, David C.; Rush, G.E.; Dahlin, Cheryl L. & Collins, W. Keith
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Formation and Reactivity of Biogenic Iron Microminerals

Description: The overall purpose of the project was to explore and quantify the processes that control the formation and reactivity of biogenic iron microminerals and their impact on the solubility of metal contaminants. The research addressed how surface components of bacterial cells, extracellular organic material, and the aqueous geochemistry of the DIRB microenvironment impacts the mineralogy, chemical state and micromorphology of reduced iron phases.
Date: August 15, 2001
Creator: Beveridge, Terrance J. & Ferris, F. Grant
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Effect of catalyst structure on oxidative dehydrogenation of ethane and propane on alumina-supported vanadia

Description: The catalytic properties of Al2O3-supported vanadia with a wide range of VOx surface density (1.4-34.2 V/nm2) and structure were examined for the oxidative dehydrogenation of ethane and propane. UV-visible and Raman spectra showed that vanadia is dispersed predominantly as isolated monovanadate species below {approx}2.3 V/nm2. As surface densities increase, two-dimensional polyvanadates appear (2.3-7.0 V/nm2) along with increasing amounts of V2O5 crystallites at surface densities above 7.0 V/nm… more
Date: September 11, 2001
Creator: Argyle, Morris D.; Chen, Kaidong; Bell, Alexis T. & Iglesia, Enrique
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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High-Resolution Energy-Selected Study of the Reaction NH3+ -> NH2 ++H: Accurate Thermo Chemistry for the NH2/NH2+ and NH3/NH3 + Systems

Description: Employing the newly developed high-resolution pulsed field ionization-photoelectron (PFI-PE)-photoion coincidence (PFI-PEPICO) technique, we have examined the dissociation of energy-selected NH{sub 3}{sup +} to form NH{sub 2}{sup +} + H near its threshold. The breakdown curves for NH{sub 2}{sup +} and NH{sub 3}{sup +} thus obtained yield a value of 15.765 {+-} 0.001 eV for the 0 K dissociation threshold or appearance energy (AE) for NH{sub 2}{sup +} from NH{sub 3}. This value, together with the… more
Date: March 1, 2001
Creator: Song, Y.; Qian, X. M.; Lau, K. C.; Ng, C. Y.; Liu, J. B. & Chen, W. W.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Capillary Electrophoresis - Optical Detection Systems

Description: Molecular recognition systems are developed via molecular modeling and synthesis to enhance separation performance in capillary electrophoresis and optical detection methods for capillary electrophoresis. The underpinning theme of our work is the rational design and development of molecular recognition systems in chemical separations and analysis. There have been, however, some subtle and exciting shifts in our research paradigm during this period. Specifically, we have moved from mostly separa… more
Date: August 6, 2001
Creator: Sepaniak, M. J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Effect of secondary structure on the potential of mean force for poly-L-lysine in the alpha-Helix and beta-sheet conformations

Description: Because poly-L-lysine (PLL) can exist in the {alpha}-helix or {beta}-sheet conformation depending on solution preparation and solution conditions, PLL is a suitable candidate to probe the dependence of protein interactions on secondary structure. The osmotic second virial coefficient and weight-average molecular weight are reported from low-angle laser-light scattering measurements for PLL as a function of NaCl concentration, pH, and {alpha}-helix or {beta}-sheet content. Interactions between P… more
Date: October 30, 2001
Creator: Grigsby, J.J.; Blanch, H.W. & Prausnitz, J.M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Isolation of Metals from Liquid Wastes: Reactive Scavenging by Sorbets in Turbulent Reactors

Description: The objective of this work is to develop the fundamental knowledge base for the design of a broad class of high-temperature reactive capture processes to treat metals-bearing liquid waste in the DOE inventory. The major thrust is devoted to understanding phenomena that govern process performance and are critical to achieving emission specifications.
Date: June 2001
Creator: Wendt, Jost O. L.; Kerstein, Alan R.; Linak, William P.; Pearlstein, Arne J. & Scheeline, Alexander
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Thermodynamics and Complexation Reactions of Anionic Silicate Species

Description: Highly basic tank wastes contain several important radionuclides, including {sup 90}Sr, {sup 99}Tc, and {sup 60}Co as well as actinide elements (isotopes of U, Pu and Am). A fraction of these wastes are known to have leaked into the vadose zone at the Hanford Site. Upon entering the sediments in the vadose zone, such highly basic solutions dissolve concentrations of silica from the silica and aluminosilicate minerals present in subsurface. These dissolution reactions alter the chemical composit… more
Date: June 1, 2001
Creator: Choppin, Gregory R. & Felmy, Andrew R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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An Investigation of Model Catalyzed Hydrocarbon Formation Reactions

Description: Work was focused on two areas aimed at understanding the chemistry of realistic catalytic systems: (1) The synthesis and characterization of model supported olefin metathesis catalysts. (2) Understanding the role of the carbonaceous layer present on Pd(111) single crystal model catalysts during reaction.
Date: May 2, 2001
Creator: Tysoe, W. T.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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