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MULTISCALE MODELING OF POLYMER NANOCOMPOSITES

Description: Polymer Nanocomposites are an important class of nanomaterials with potential applications including but not limited to structural and cushion materials, electromagnetic and heat shields, conducting plastics, sensors, and catalysts for various chemical and bio processes. Success in most such applications hinges on molecular-level control of structure and assembly, and a deep understanding of how the overall morphology of various components and the interfaces between them affect the composite pr… more
Date: July 16, 2007
Creator: Maiti, A
Partner: UNT Libraries Government Documents Department
open access

Dynamics of Adipocyte Turnover in Humans

Description: Obesity is increasing in an epidemic fashion in most countries and constitutes a public health problem by enhancing the risk for cardiovascular disease and metabolic disorders such as type 2 diabetes. Owing to the increase in obesity, life expectancy may start to decrease in developed countries for the first time in recent history. The factors determining fat mass in adult humans are not fully understood, but increased lipid storage in already developed fat cells is thought to be most important… more
Date: July 16, 2007
Creator: Spalding, K; Arner, E; Westermark, P; Bernard, S; Buchholz, B; Bergmann, O et al.
Partner: UNT Libraries Government Documents Department
open access

Relative Biological Effectiveness of HZE Fe Ions for Induction of Micro-Nuclei at Low Doses

Description: Dose-response curves for induction of micro-nuclei (MN) was measured in Chinese hamster V79 and xrs6 (Ku80-) cells and in human mammary epithelial MCF10A cells in the dose range of 0.05-1 Gy. The Chinese Hamster cells were exposed to 1 GeV/u Fe ions, 600 MeV/u Fe ions, and 300 MeV/u Fe ions (LETs of 151, 176 and 235 keV/{micro}m respectively) as well as with 320 kVp X-rays as reference. Second-order polynomials were fitted to the induction curves and the initial slopes (the alpha values) were u… more
Date: January 16, 2007
Creator: Groesser, Torsten; Chun, Eugene & Rydberg, Bjorn
Partner: UNT Libraries Government Documents Department
open access

Estimates of Optimal Backward Perturbations for Linear LeastSquares Problems

Description: Numerical tests are used to validate a practical estimatefor the optimal backward errors of linear least squares problems. Thissolves a thirty-year-old problem suggested by Stewart andWilkinson.
Date: July 16, 2007
Creator: Grcar, Joseph F.; Saunders, M.A. & Su, Zheng
Partner: UNT Libraries Government Documents Department
open access

On the non-invariance of space and time scale ranges under Lorentztransformation, and its implications for the study of relativisticinteractions

Description: We present an analysis which shows that the ranges of space and time scales spanned by a system are not invariant under the Lorentz transformation. This implies the existence of a frame of reference which minimizes an aggregate measure of the range of space and time scales. Such a frame is derived for example cases: free electron laser, laser-plasma accelerator, and particle beam interacting with electron clouds. Implications for experimental, theoretical and numerical studies are discussed. Th… more
Date: January 16, 2007
Creator: Vay, J. L.
Partner: UNT Libraries Government Documents Department
open access

Effect of Titanium Substitution on the Compatiblity of Electrodeswith Pyrrolidinium-Based Ionic Liquid Electrolytes

Description: The quest for the development of rechargeable lithium-metal batteries has attracted vigorous worldwide research efforts because this system offers the highest theoretical specific energy [1]. For this to be achieved, the repetitive deposition and stripping of lithium must be close to fully reversible. Thus, alternative electrolytes have been investigated, such as the room-temperature ionic liquid (RTILs). Lithium can be cycled with a high degree of reversibility with efficiencies exceeding 99% … more
Date: May 16, 2007
Creator: Saint, Juliette A.; Shin, Joon-Ho; Best, Adam; Hollenkamp,Anthony; Kerr, John & Doeff, Marca M.
Partner: UNT Libraries Government Documents Department
open access

Lepton Flavour Violation And Baryon Number Non-Conservation in tau to Lambda + h

Description: We have searched for the violation of baryon number B and lepton number L in the (B - L)-conserving modes {tau}{sup -} {yields} {bar {Lambda}}{pi}{sup -} and {tau}{sup -} {yields} {bar {Lambda}}K{sup -} as well as the (B - L)-violating modes {tau}{sup -} {yields} {Lambda}{pi}{sup -} and {tau}{sup -} {yields} {Lambda}K{sup -} using 237 fb{sup -1} of data collected with the BaBar detector at the PEP-II asymmetric-energy e{sup +}e{sup -} storage rings. We do not observe any signal and we determine… more
Date: November 16, 2007
Creator: Lafferty, G.D.
Partner: UNT Libraries Government Documents Department
open access

Kaolinite dissolution and precipitation kinetics at 22oC and pH4

Description: Dissolution and precipitation rates of low defect Georgia kaolinite (KGa-1b) as a function of Gibbs free energy of reaction (or reaction affinity) were measured at 22 C and pH 4 in continuously stirred flow through reactors. Steady state dissolution experiments showed slightly incongruent dissolution, with a Si/Al ratio of about 1.12 that is attributed to the re-adsorption of Al on to the kaolinite surface. No inhibition of the kaolinite dissolution rate was apparent when dissolved aluminum was… more
Date: July 16, 2007
Creator: Yang, Li & Steefel, Carl I.
Partner: UNT Libraries Government Documents Department
open access

Commissioning Results of the LCLS Injector

Description: The Linac Coherent Light Source (LCLS) is a SASE xray Free-Electron Laser (FEL) project presently under construction at SLAC. The injector section, from drive-laser and RF photocathode gun through first bunch compressor chicane, was installed in fall 2006. Initial system commissioning with an electron beam has recently been completed. The second phase of construction, including second bunch compressor and full linac, is planned for 2008. In this paper, we report experimental results and experie… more
Date: November 16, 2007
Creator: Dowell, D. H.; Akre, R.; Ding, Y.; Emma, P.; Frisch, J.; Gilevich, S. et al.
Partner: UNT Libraries Government Documents Department
open access

ADVANCED WAVEFORM SIMULATION FOR SEISMIC MONITORING EVENTS

Description: Comprehensive test ban monitoring in terms of location and discrimination has progressed significantly in recent years. However, the characterization of sources and the estimation of low yields remains a particular challenge. As the recent Korean shot demonstrated, we can probably expect to have a small set of teleseismic, far-regional and high-frequency regional data to analyze in estimating the yield of an event. Since stacking helps to bring signals out of the noise, it becomes useful to con… more
Date: July 16, 2007
Creator: Helmberger, D; Tromp, J & Rodgers, A
Partner: UNT Libraries Government Documents Department
open access

Autocatalytic water dissociation on Cu(110) at near ambient conditions

Description: Autocatalytic dissociation of water on the Cu(110) metal surface is demonstrated based on X-ray photoelectron spectroscopy studies carried out in-situ under near ambient conditions of water vapor pressure (1 Torr) and temperature (275-520 K). The autocatalytic reaction is explained as the result of the strong hydrogen-bond in the H{sub 2}O-OH complex of the dissociated final state, which lowers the water dissociation barrier according to the Broensted-Evans-Polanyi relations. A simple chemical … more
Date: May 16, 2007
Creator: Mulleregan, Alice; Andersson, Klas; Ketteler, Guido; Bluhm, Hendrik; Yamamoto, Susumu; Ogasawara, Hirohito et al.
Partner: UNT Libraries Government Documents Department
open access

Strings on AdS2 and the high-energy limit of noncritical M-theory

Description: Abstract. Noncritical M-theory in 2+1 dimensions has been defined as a double-scaling limit of a nonrelativistic Fermi liquid on a flat two-dimensional plane. Here we study this noncritical M-theory in the limit of high energies, analogous to the alpha' --> infinity limit of string theory. In the related case of two-dimensional Type 0A strings, it has been argued that the conformal alpha' --> infinity limit leads to AdS_2 with a propagating fermion whose mass is set by the value o… more
Date: April 16, 2007
Creator: Horava, Petr; Horava, Petr & Keeler, Cynthia A.
Partner: UNT Libraries Government Documents Department
open access

Evaluation of the Gas Production Potential of Marine HydrateDeposits in the Ulleung Basin of the Korean East Sea

Description: Although significant hydrate deposits are known to exist in the Ulleung Basin of the Korean East Sea, their survey and evaluation as a possible energy resource has not yet been completed. However, it is possible to develop preliminary estimates of their production potential based on the limited data that are currently available. These include the elevation and thickness of the Hydrate-Bearing Layer (HBL), the water depth, and the water temperature at the sea floor. Based on this information, we… more
Date: November 16, 2007
Creator: Moridis, George J.; Reagan, Matthew T.; Kim, Se-Joon; Seol,Yongkoo & Zhang, Keni
Partner: UNT Libraries Government Documents Department
open access

Radiative Penguin Decays at the B Factories

Description: In this article, I review the most recent results in radiative penguin decays from the B factories Belle and BABAR. Most notably, I will talk about the recent new observations in the decays B {yields} ({rho}/{omega}) {gamma}, a new analysis technique in b {yields} s{gamma}, and first measurements of radiative penguin decays in the B{sup 0}{sub s} meson system. Finally, I will summarize the current status and future prospects of radiative penguin B physics at the B factories.
Date: November 16, 2007
Creator: Koneke, Karsten
Partner: UNT Libraries Government Documents Department
open access

Classification of Multiple Types of Organic Carbon Composition in Atmospheric Particles by Scanning Transmission X-Ray Microscopy Analysis

Description: A scanning transmission X-ray microscope at the Lawrence Berkeley National Laboratory is used to measure organic functional group abundance and morphology of atmospheric aerosols. We present a summary of spectra, sizes, and shapes observed in 595 particles that were collected and analyzed between 2000 and 2006. These particles ranged between 0.1 and 12 mm and represent aerosols found in a large range of geographical areas, altitudes, and times. They include samples from seven different field ca… more
Date: May 16, 2007
Creator: Kilcoyne, Arthur L; Takahama, S.; Gilardoni, S.; Russell, L.M. & Kilcoyne, A.L.D.
Partner: UNT Libraries Government Documents Department
open access

Extracting longitudinal shower developmentinformation from crystal calorimetry plus tracking

Description: We propose a novel approach to derive longitudinal shower development information from a longitudinally unsegmented calorimeter such as the BaBar electromagnetic calorimeter by utilizing tracking information in conjunction with that of calorimetry. We show that using this information as part of an electron identification algorithm results in a significant reduction in the pion misidentification probability for low momentum particles. We also demonstrate how this information provides general cha… more
Date: November 16, 2007
Creator: Brown, D.N.; Ilic, J. & Mohanty, G.B.
Partner: UNT Libraries Government Documents Department
open access

CORROSION OF LEAD SHIELDING IN NUCLEAR MATERIALS PACKAGES

Description: Inspection of United States-Department of Energy (US-DOE) model 9975 nuclear materials shipping package revealed corrosion of the lead shielding induced by off-gas constituents from organic components in the package. Experiments were performed to determine the corrosion rate of lead when exposed to off-gas or degradation products of these organic materials. The results showed that the room temperature vulcanizing (RTV) sealant was the most corrosive organic species followed by the polyvinyl ace… more
Date: November 16, 2007
Creator: Subramanian, K & Kerry Dunn, K
Partner: UNT Libraries Government Documents Department
open access

Making Amines Strong Bases: Thermodynamic Stabilization ofProtonated Guests in a Highly-Charged Supramolecular Host

Description: A highly-charged, cavity-containing supramolecular assembly formed by metal-ligand interactions acts as a host to dramatically shift the effective basicity of encapsulated protonated amine guests. The scope of encapsulated protonated amine and phosphine guests shows size selectivity consistent with a constrained binding environment. Protonation of the encapsulated guests is confirmed by {sup 31}P NMR studies, mass spectrometry studies, and the pH dependence of guest encapsulation. Rates of gues… more
Date: April 16, 2007
Creator: Pluth, Michael D.; Bergman, Robert G. & Raymond, Kenneth N.
Partner: UNT Libraries Government Documents Department
open access

Electronic structure of cobalt nanocrystals suspended inliquid

Description: The electronic structure of cobalt nanocrystals suspended in liquid as a function of size has been investigated using in-situ x-ray absorption and emission spectroscopy. A sharp absorption peak associated with the ligand molecules is found that increases in intensity upon reducing the nanocrystal size. X-ray Raman features due to d-d and to charge-transfer excitations of ligand molecules are identified. The study reveals the local symmetry of the surface of {var_epsilon}-Co phase nanocrystals, … more
Date: July 16, 2007
Creator: Liu, Hongjian; Guo, Jinghua; Yin, Yadong; Augustsson, Andreas; Dong, Chungli; Nordgren, Joseph et al.
Partner: UNT Libraries Government Documents Department
open access

Relativistic Dark Matter at the Galactic Center

Description: In a large region of the supersymmetry parameter space, the annihilation cross section for neutralino dark matter is strongly dependent on the relative velocity of the incoming particles. We explore the consequences of this velocity dependence in the context of indirect detection of dark matter from the galactic center. We find that the increase in the annihilation cross section at high velocities leads to a flattening of the halo density profile near the galactic center and an enhancement of t… more
Date: November 16, 2007
Creator: Amin, Mustafa A.; /Stanford U., Phys. Dept. /KIPAC, Menlo Park & Wizansky, Tommer
Partner: UNT Libraries Government Documents Department
open access

Measurement of the beta-neutrino correlation of sodium-21 usingshakeoff electrons

Description: The beta-neutrino correlation coefficient, a_beta nu, ismeasured in 21Na by detecting the time-of-flight of the recoil nucleusdetected in coincidence with the atomic electrons shaken off in betadecay. The sample of 21Na is confined in a magneto-optic trap. Highdetection efficiency allows low trap density, which suppresses thephotoassociation of molecular sodium, which can cause a large systematicerror. Suppressing the fraction of trapped atoms in the excited stateusing a dark trap also reduces … more
Date: January 16, 2007
Creator: Vetter, Paul A.; Abo-Shaeer, Jamil R.; Freedman, Stuart J. & Maruyama, Reina
Partner: UNT Libraries Government Documents Department
open access

Elastic constants and volume changes associated with two high-pressure rhombohedral phase transformations in vanadium

Description: We present results from ab-initio electronic-structure calculations of mechanical properties of the rhombohedral phase of vanadium reported in recent experiments (R Ia), and other predicted high-pressure phases (R Ib and bcc), focusing on properties relevant to dynamic experiments. We find that of the three transitions the largest volume collapse (1.3%) is for the R Ia to R Ib transition. Calculations of the single crystal and polycrystal elastic constants reveal a remarkably small discontinuit… more
Date: October 16, 2007
Creator: Lee, B; Rudd, R E; Klepeis, J E & Becker, R
Partner: UNT Libraries Government Documents Department
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