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Structural and electronic properties of carbon nanotube tapers

Description: Article on structural and electronic properties of carbon nanotube tapers, a set of nanostructures comprised of straight tubular sections with decreasing diameters, joined to each other via conical funnels and terminated with a hemispherical cap.
Date: October 29, 2001
Creator: Meunier, Vincent; Buongiorno Nardelli, Marco; Roland, Christopher & Bernholc, Jerry
Partner: UNT College of Arts and Sciences
open access

First-principles investigations of the dielectric properties of polypropylene/metal-oxide interfaces

Description: Article on first-principles investigations of the dielectric properties of polypropylene/metal-oxide interfaces. Nanoscale-resolved dielectric properties of polypropylene/metal-oxide (alumina, PbTiO₃) interfaces and of the corresponding surfaces are investigated via first-principles calculations.
Date: October 30, 2009
Creator: Yu, Liping; Ranjan, Vivek; Buongiorno Nardelli, Marco & Bernholc, Jerry
Partner: UNT College of Arts and Sciences
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Development of ITER 15 MA ELMy H-mode Inductive Scenario

Description: The poloidal field (PF) coil system on ITER, which provides both feedforward and feedback control of plasma position, shape, and current, is a critical element for achieving mission performance. Analysis of PF capabilities has focused on the 15 MA Q = 10 scenario with a 300-500 s flattop burn phase. The operating space available for the 15 MA ELMy H-mode plasma discharges in ITER and upgrades to the PF coils or associated systems to establish confidence that ITER mission objectives can be reach… more
Date: October 16, 2008
Creator: Kessel, C. E.; Campbell, D.; Gribov, Y.; Saibene, G.; Ambrosino, G.; Casper, T. et al.
Partner: UNT Libraries Government Documents Department
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A Top to Bottom Lithospheric Study of Africa and Arabia

Description: We study the lithospheric structure of Africa, Arabia and adjacent oceanic regions with fundamental-mode surface waves over a wide period range. Including short period group velocities allows us to examine shallower features than previous studies of the whole continent. In the process, we have developed a crustal thickness map of Africa. Main features include crustal thickness increases under the West African, Congo, and Kalahari cratons. We find crustal thinning under Mesozoic and Cenozoic rif… more
Date: October 31, 2006
Creator: Pasyanos, M
Partner: UNT Libraries Government Documents Department
open access

Increasing FTIR spectromicroscopy speed and resolution through compressive imaging

Description: At the Advanced Light Source at Lawrence Berkeley National Laboratory, we are investigating how to increase both the speed and resolution of synchrotron infrared imaging. Synchrotron infrared beamlines have diffraction-limited spot sizes and high signal to noise, however spectral images must be obtained one point at a time and the spatial resolution is limited by the effects of diffraction. One technique to assist in speeding up spectral image acquisition is described here and uses compressive … more
Date: October 15, 2007
Creator: Gallet, Julien; Riley, Michael; Hao, Zhao & Martin, Michael C
Partner: UNT Libraries Government Documents Department
open access

Web-Ice: Integrated Data Collection and Analysis for Macromolecular Crystallography

Description: New software tools are introduced to facilitate diffraction experiments involving largenumbers of crystals. While existing programs have long provided a framework for lattice indexing, Bragg spot integration, and symmetry determination, these initial data processing steps often require significant manual effort. This limits the timely availability of data analysis needed for high-throughput procedures, including the selection of the best crystals from a large sample pool, and the calculation of… more
Date: October 10, 2007
Creator: Gonzalez, Ana; Gonzalez, Ana; Moorhead, Penjit; McPhillips, Scott E.; Song, Jinhu; Sharp, Ken et al.
Partner: UNT Libraries Government Documents Department
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Multipole Shimming of Permanent Magnets Using Harmonic CorrectorRings

Description: Shimming systems are required to provide sufficient fieldhomogeneity for high resolution NMR. In certain specialized applications,such as rotating-field NMR and portable (ex-situ) NMR, permanentmagnet-based shimming systems can provide considerable advantages. Wepresent a simple two-dimensional shimming method based on harmoniccorrector rings which can provide arbitrary multipole order shimmingcorrections. Results demonstrate, for example, that quadrupolar ordershimming improves the linewidth b… more
Date: October 23, 2006
Creator: Jachmann, Rebecca C.; Trease, David R.; Bouchard, Louis-S.; Sakellariou, Dimitris; Martin, Rachel W.; Schlueter, Ross D. et al.
Partner: UNT Libraries Government Documents Department
open access

The energy dependence of the total charm cross section

Description: We discuss the energy dependence of the total charm cross section and some of its theoretical uncertainties including the quark mass, scale choice and the parton densities. We compare the next-to-leading order calculation of the total cross section with results obtained using PYTHIA.
Date: October 18, 2007
Creator: Vogt, R
Partner: UNT Libraries Government Documents Department
open access

Pump and probe damage testing for investigation of transient material modifications associated with laser damage in optical materials

Description: Laser-induced breakdown in the bulk of transparent dielectric materials is associated with the generation of extreme localized conditions of temperatures and pressures. In this work, we perform pump and probe damage testing experiments to investigate the evolution of transient absorption by the host material arising from modifications following confined laser energy deposition in fused silica and DKDP materials. Specifically, we measure the size of the damage sites observed in the region of spa… more
Date: October 18, 2007
Creator: Negres, R A; Feit, M D; DeMange, P; Bude, J D & Demos, S G
Partner: UNT Libraries Government Documents Department
open access

Metagenomic and Functional Analysis of Hindgut Microbiota of a Wood-Feeding Higher Termite

Description: From the standpoints of both basic research and biotechnology, there is considerable interest in reaching a clearer understanding of the diversity of biological mechanisms employed during lignocellulose degradation. Globally, termites are an extremely successful group of wood-degrading organisms and are therefore important both for their roles in carbon turnover in the environment and as potential sources of biochemical catalysts for efforts aimed at converting wood into biofuels. Only recently… more
Date: October 1, 2007
Creator: Warnecke, Falk; Warnecke, Falk; Luginbuhl, Peter; Ivanova, Natalia; Ghassemian, Majid; Richardson, Toby H. et al.
Partner: UNT Libraries Government Documents Department
open access

Calculation Of Change-Changing Cross Sections Of IONS Or Atoms Colliding With Fast IONS Using The Classical Trajectory Method

Description: Evaluation of ion-atom charge-changing cross sections is needed for many accelerator applications. A classical trajectory Monte Carlo (CTMC) simulation has been used to calculate ionization and charge exchange cross sections. For benchmarking purposes, an extensive study has been performed for the simple case of hydrogen and helium targets in collisions with various ions. Despite the fact that the simulation only accounts for classical mechanics, the calculations are comparable to experimental … more
Date: October 10, 2008
Creator: Kaganovich, I. D., Shnidman, Ariel, Mebane, Harrison, Davidson, R.C.
Partner: UNT Libraries Government Documents Department
open access

Syntheses, Structure, Magnetism, and Optical Properties of Lutetium-based Interlanthanide Selenides

Description: Ln{sub 3}LuSe{sub 6} (Ln = La, Ce), {beta}-LnLuSe{sub 3} (Ln = Pr, Nd), and Ln{sub x}Lu{sub 4-x}Se{sub 6} (Ln = Sm, Gd; x = 1.82, 1.87) have been synthesized using a Sb{sub 2}Se{sub 3} flux at 1000 C. Ln{sub 3}LuSe{sub 6} (Ln = La, Ce) adopt the U{sub 3}ScS{sub 6}-type three-dimensional structure, which is constructed from two-dimensional {infinity}{sup 2} [Ln{sub 3}Se{sub 6}]{sup 3-} slabs with the gaps between these slabs filled by octahedrally coordinated Lu{sup 3+} ions. The series of {beta… more
Date: October 1, 2007
Creator: Booth, Corwin H; Jin, Geng Bang; Choi, Eun Sang; Guertin, Robert P.; Brooks, James S.; Booth, Corwin H. et al.
Partner: UNT Libraries Government Documents Department
open access

Tevatron results on the discovery of sigma^(*)_b, b_s oscillations and the measurement of delta m_s, the lifetime difference delta gamma_s and the cp-violating phase phi

Description: The author discusses results from the Tevatron experiments on mixing and CP-violation in B{sub s} mesons, including the observation of B{sub s} oscillations and the first precision measurement of the mixing frequency, as well as a measurement of the lifetime difference {Delta}{Lambda}{sub s} and the first measurement of the CP-violating phase {delta}{sub s}. The author also briefly reports on the observation of four new bottom baryons at CDF.
Date: October 1, 2007
Creator: Heijboer, Aart
Partner: UNT Libraries Government Documents Department
open access

Water, law, science

Description: In a world with water resources severely impacted bytechnology, science must actively contribute to water law. To this end,this paper is an earth scientist s attempt to comprehend essentialelements of water law, and to examine their connections to science.Science and law share a common logical framework of starting with apriori prescribed tenets, and drawing consistent inferences. In science,observationally established physical laws constitute the tenets, while inlaw, they stem from social valu… more
Date: October 17, 2007
Creator: Narasimhan, T.N.
Partner: UNT Libraries Government Documents Department
open access

Progress In High Temperature Electrolysis At The Idaho National Laboratory

Description: The United States is considering the development of a domestic hydrogen-based energy economy. Hydrogen is of particular interest as a secondary energy carrier because it has the potential to be storable, transportable, environmentally benign, and useful in many chemical processes. Obviously, before a hydrogen economy can be implemented, an efficient and environmentally friendly means for large scale hydrogen production must be identified, proven, and developed. Hydrogen is now produced primaril… more
Date: October 1, 2007
Creator: Stoots, Carl M.; E.O'Brien, James; Herring, J. Steve & Hartvigsen, Joseph
Partner: UNT Libraries Government Documents Department
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A Compact Linac for Proton Therapy Based on a Dielectric Wall Accelerator

Description: A novel compact CT-guided intensity modulated proton radiotherapy (IMPT) system is described. The system is being designed to deliver fast IMPT so that larger target volumes and motion management can be accomplished. The system will be ideal for large and complex target volumes in young patients. The basis of the design is the dielectric wall accelerator (DWA) system being developed at the Lawrence Livermore National Laboratory (LLNL). The DWA uses fast switched high voltage transmission lines … more
Date: October 29, 2007
Creator: Caporaso, G. J.; Mackie, T. R.; Sampayan, S.; Chen, Y.; Wang, L.; Blackfield, D. et al.
Partner: UNT Libraries Government Documents Department
open access

Elastic and transport properties in polycrystals of crackedgrains: Cross-property relations and microstructure

Description: Some arguments of Bristow (1960) concerning the effects of cracks on elastic and transport (i.e., electrical or thermal conduction) properties of cold-worked metals are reexamined. The discussion is posed in terms of a modern understanding of bounds and estimates for physical properties of polycrystals--in contrast to Bristow's approach using simple mixture theory. One type of specialized result emphasized here is the cross-property estimates and bounds that can be obtained using the methods pr… more
Date: October 2, 2007
Creator: Berryman, J.G.
Partner: UNT Libraries Government Documents Department
open access

Top Jets at the LHC

Description: We investigatethe reconstruction of high pT hadronically-decaying top quarksat the Large Hadron Collider. One of the main challenges in identifying energetictop quarks is that the decay products become increasingly collimated. This reducesthe efficacy of conventional reconstruction methods that exploit the topology of thetop quark decay chain. We focus on the cases where the decay products of the topquark are reconstructed as a single jet, a"top-jet." The most basic"top-tag"… more
Date: October 6, 2008
Creator: Almeida, L.G.; Lee, S.J.; Perez, G.; Sung, I. & Virzi, J.
Partner: UNT Libraries Government Documents Department
open access

Spatial resolution limits for synchrotron-based infrared spectromicroscopy

Description: Detailed spatial resolution tests were performed on beamline 1.4.4 at the Advanced Light Source synchrotron facility in Berkeley, CA. The high-brightness synchrotron source is coupled at this beamline to a Thermo-Electron Continumum XL infrared microscope. Two types of resolution tests in both the mid-IR (using a KBr beamsplitter and an MCT-A* detector) and in the near-IR (using a CaF2 beamsplitter and an InGaAS detector) were performed and compared to a simple diffraction-limited spot size mod… more
Date: October 15, 2007
Creator: Levenson, Erika; Lerch, Philippe & Martin, Michael C.
Partner: UNT Libraries Government Documents Department
open access

Abstract: Air, Thermal and Water Management for PEM Fuel Cell Systems

Description: PEM fuel cells are excellent candidates for transportation applications due to their high efficiencies. PEM fuel cell Balance of Plant (BOP) components, such as air, thermal, and water management sub-systems, can have a significant effect on the overall system performance, but have traditionally not been addressed in research and development efforts. Recognizing this, the U.S. Department of Energy and Honeywell International Inc. are funding an effort that emphasizes the integration and optimiz… more
Date: October 1, 2008
Creator: Mirza, Mark K. Gee Zia
Partner: UNT Libraries Government Documents Department
open access

Current Activities of the ASME Subgroup NUPACK

Description: Current activities of the American Society of Mechanical Engineers (ASME), Section III Subgroup on Containment Systems for Spent Fuel High-Level Waste Transport Packagings (also known as Subgroup NUPACK) are reviewed with emphasis on the recent revision of Subsection WB. Also, brief insightson new proposals for the development of rules for internal support structures and for a strain-based acceptance criteria are provided.
Date: October 1, 2007
Creator: Foster, Gerald M.; Morton, D. Keith & McConnell, Paul
Partner: UNT Libraries Government Documents Department
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