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Discontinuous Galerkin solution of the Navier-Stokes equations on deformable domains

Description: We describe a method for computing time-dependent solutions to the compressible Navier-Stokes equations on variable geometries. We introduce a continuous mapping between a fixed reference configuration and the time varying domain, By writing the Navier-Stokes equations as a conservation law for the independent variables in the reference configuration, the complexity introduced by variable geometry is reduced to solving a transformed conservation law in a fixed reference configuration, The spati… more
Date: January 13, 2009
Creator: Persson, P.-O.; Bonet, J. & Peraire, J.
Partner: UNT Libraries Government Documents Department
open access

MAXI and GLAST Studies of Jets in Active Galaxies

Description: The recent launch of GLAST--coinciding with the MAXI workshop--opens a new era for studies of jet-dominated active galaxies, known as blazars. While the emission processes operating in various spectral bands in blazars are reasonably well understood, the knowledge of the details of the structure of the jet, location of the dissipation region with respect to the accreting black hole, and coupling of the jet to the accretion process are known only at a rudimentary level. Blazars are variable, and… more
Date: October 13, 2008
Creator: Madejski, Greg; Kataoka, Jun & Sikora, Marek
Partner: UNT Libraries Government Documents Department
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Modeling and Experimental Investigation of Methylcyclohexane Ignition in a Rapid Compression Machine

Description: A new mechanism for the oxidation of methylcyclohexane has been developed. The mechanism combined a newly-developed low temperature mechanism with a previously developed high temperature mechanism. Predictions from the chemical kinetic model have been compared to experimentally measured ignition delay times from a rapid compression machine. Predicted ignition delay times using the initial estimates of the methylcyclohexyl peroxy radical isomerization rate constants were much longer than those m… more
Date: October 13, 2005
Creator: Pitz, W J; Naik, C V; Mhaold?in, T N; Curran, H J; Orme, J P; Simmie, J M et al.
Partner: UNT Libraries Government Documents Department
open access

Volumetric data analysis using Morse-Smale complexes

Description: The 3D Morse-Smale complex is a fundamental topological construct that partitions the domain of a real-valued function into regions having uniform gradient flow behavior. In this paper, we consider the construction and selective presentation of cells of the Morse-Smale complex and their use in the analysis and visualization of scientific datasets. We take advantage of the fact that cells of different dimension often characterize different types of features present in the data. For example, crit… more
Date: October 13, 2005
Creator: Natarajan, V & Pascucci, V
Partner: UNT Libraries Government Documents Department
open access

Radiocarbon Based Ages and Growth Rates: Hawaiian Deep Sea Corals

Description: The radial growth rates and ages of three different groups of Hawaiian deep-sea 'corals' were determined using radiocarbon measurements. Specimens of Corallium secundum, Gerardia sp., and Leiopathes glaberrima, were collected from 450 {+-} 40 m at the Makapuu deep-sea coral bed using a submersible (PISCES V). Specimens of Antipathes dichotoma were collected at 50 m off Lahaina, Maui. The primary source of carbon to the calcitic C. secundum skeleton is in situ dissolved inorganic carbon (DIC). U… more
Date: January 13, 2006
Creator: Roark, E. B.; Guilderson, T. P.; Dunbar, R. B. & Ingram, B. L.
Partner: UNT Libraries Government Documents Department
open access

Drosophila by the dozen

Description: This year's conference on Drosophila research illustratedwell the current focus of Drosophila genomics on the comprehensiveidentification of functional elements in the genome sequence, includingmRNA transcripts arising from multiple alternative start sites and splicesites, a multiplicity of noncoding transcripts and small RNAs,identification of binding sites for transcription factors, sequenceconservation in related species and sequence variation within species.Resources and technologies for ge… more
Date: July 13, 2007
Creator: Celniker, Susan E. & Hoskins, Roger A.
Partner: UNT Libraries Government Documents Department
open access

The Nevada Test Site as a Lunar Analog Test Area

Description: The Nevada Test Site (NTS) is a large (1,350 square miles) secure site currently operated by National Security Technologies, LLC (NSTec), for the U.S. Department of Energy and was established in 1951 to provide a venue for testing nuclear weapons. Three areas with a variety of elevation and geological parameters were used for testing, but the largest number of tests was in Yucca Flat. The Yucca Flat area is approximately 5 miles wide and 20 miles long and approximately 460 subsidence craters re… more
Date: February 13, 2007
Creator: Freid, Sheldon
Partner: UNT Libraries Government Documents Department
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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

Action-Oriented Benchmarking: Concepts and Tools

Description: Most energy benchmarking tools provide static feedback on how one building compares to a larger set of loosely similar buildings, without providing information at the end-use level or on what can be done to reduce consumption, cost, or emissions. In this article--Part 1 of a two-part series--we describe an 'action-oriented benchmarking' approach, which extends whole-building energy benchmarking to include analysis of system and component energy use metrics and features. Action-oriented benchmar… more
Date: February 13, 2008
Creator: Commission, California Energy; Mathew, Paul; Mills, Evan; Mathew, Paul; Piette, Mary Ann; Bourassa, Norman et al.
Partner: UNT Libraries Government Documents Department
open access

The work function of sub-monolayer cesium-covered gold: A photoelectronspectroscopy study

Description: Using visible and X-ray photoelectron spectroscopy we measured the work function of a Au(111) surface at a well-defined sub-monolayer coverage of Cs. For a Cs coverage producing a photoemission maximum with a He-Ne laser, the work function is 1.61 {+-} 0.08 eV consistent with previous assumptions used to analyze vibrationally promoted electron emission. A discussion of possible Cs layer structures is also presented.
Date: June 13, 2008
Creator: LaRue, J. L.; White, J. D.; Nahler, N. H.; Liu, Z.; Sun, Y.; Pianetta, P. A. et al.
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

SYNCHROTRON RADIATION AND RING FORMATION IN THE ELECTRON RING ACCELERATOR

Description: We discuss the possibility of using synchrotron radiation to form electron rings having a very high electric field to hold the ions inside the ring. The formulas describing bow the energy and the dimension of the ring change under the effect of synchrotron radiation are derived, and a numerical example is given.
Date: May 13, 1970
Creator: Pellegrini, C.
Partner: UNT Libraries Government Documents Department
open access

Nuclear Energy Readiness Indicator Index (NERI): A benchmarking tool for assessing nuclear capacity in developing countries

Description: Declining natural resources, rising oil prices, looming climate change and the introduction of nuclear energy partnerships, such as GNEP, have reinvigorated global interest in nuclear energy. The convergence of such issues has prompted countries to move ahead quickly to deal with the challenges that lie ahead. However, developing countries, in particular, often lack the domestic infrastructure and public support needed to implement a nuclear energy program in a safe, secure, and nonproliferatio… more
Date: July 13, 2008
Creator: Saum-Manning, L.
Partner: UNT Libraries Government Documents Department
open access

Measurement of \mathcal{B}(\tau^{-}\-->\bar{K^{0}}\pi^{-}\nu_{\tau}) Using the \babar Detector

Description: A preliminary measurement of the branching fraction {Beta}({tau}{sup -} {yields} K{sub S}{sup 0}{pi}{sup -}{nu}{sub {tau}}) is made using 384.6 fb{sup -1} of e{sup +}e{sup -} collision data provided by the PEP-II collider, operating primarily at {radical}s = 10.58 GeV, and recorded using the BABAR detector. From this they measure: {Beta}({tau}{sup -} {yields} {bar K}{sup 0}{pi}{sup -}{nu}{sub {tau}}) = (0.840 {+-} 0.004(stat) {+-} 0.023(syst))%. This result is the most precise measurement to da… more
Date: August 13, 2008
Creator: Wren, A
Partner: UNT Libraries Government Documents Department
open access

Evaluation of optical imaging and spectroscopy approaches for cardiac tissue depth assessment

Description: NIR light scattering from ex vivo porcine cardiac tissue was investigated to understand how imaging or point measurement approaches may assist development of methods for tissue depth assessment. Our results indicate an increase of average image intensity as thickness increases up to approximately 2 mm. In a dual fiber spectroscopy configuration, sensitivity up to approximately 3 mm with an increase to 6 mm when spectral ratio between selected wavelengths was obtained. Preliminary Monte Carlo re… more
Date: February 13, 2008
Creator: Lin, B; Matthews, D; Chernomordik, V; Gandjbakhche, A; Lane, S & Demos, S G
Partner: UNT Libraries Government Documents Department
open access

The US Support Program to IAEA Safeguards Priority of Training and Human Resources

Description: The U.S. Support Program to IAEA Safeguards (USSP) priority of training and human resources is aimed at providing the Department of Safeguards with an appropriate mixture of regular staff and extrabudgetary experts who are qualified to meet the IAEA's technical needs and to provide personnel with appropriate instruction to improve the technical basis and specific skills needed to perform their job functions. The equipment and methods used in inspection activities are unique, complex, and evolvi… more
Date: June 13, 2008
Creator: Queirolo,A.
Partner: UNT Libraries Government Documents Department
open access

Identification of the Origin of Monojet Signatures at the LHC

Description: Several new physics scenarios can lead to monojet signatures at the LHC. If such events are observed above the Standard Model background it will be important to identify their origin. In this paper we compare and contrast these signatures as produced in two very different pictures: vector or scalar unparticle production in the scale-invariant/conformal regime and graviton emission in the Arkani-Hamed, Dimopoulos and Dvali extra-dimensional model. We demonstrate that these two scenarios can be d… more
Date: May 13, 2008
Creator: Rizzo, Thomas G.
Partner: UNT Libraries Government Documents Department
open access

Measurements of the asymmetric, dynamic sheath around a pulse biased sphere immersed in flowing metal plasma

Description: A long-probe technique was utilized to record the expansion and retreat of the dynamic sheath around a spherical substrate immersed in pulsed cathode arc metal plasma. Positively biased, long cylindrical probes were placed on the side and downstream of a negatively pulsed biased stainless steel sphere of 1" (25.4 mm) diameter. The amplitude and width of the negative high voltage pulses (HVP) were 2 kV, 5 kV, 10 kV, and 2 mu s, 4 mu s, 10 mu s, respectively. The variation of the probe (elec… more
Date: June 13, 2008
Creator: Anders, Andre; Wu, Hongchen & Anders, Andre
Partner: UNT Libraries Government Documents Department
open access

Structural Distortions in 5-10 Nm Silver Nanoparticles Under High Pressure

Description: We present experimental evidence that silver nanoparticles in the size range of 5-10 nm undergo a reversible structural transformation under hydrostatic pressures up to 10 GPa. We have used x-ray diffraction with a synchrotron light source to investigate pressure-dependent and size-dependent trends in the crystal structure of silver nanoparticles in a hydrostatic medium compressed in a diamond-anvil cell. Results suggest a reversible linear pressure-dependent rhombohedral distortion which has n… more
Date: October 13, 2008
Creator: Koski, Kristie J.; Kamp, Noelle M.; Kunz, Martin; Knight, Jason K.; Alivisatos, A. P. & Smith, R. K.
Partner: UNT Libraries Government Documents Department
open access

Constraining Cosmic Evolution of Type Ia Supernovae

Description: We present the first large-scale effort of creating composite spectra of high-redshift type Ia supernovae (SNe Ia) and comparing them to low-redshift counterparts. Through the ESSENCE project, we have obtained 107 spectra of 88 high-redshift SNe Ia with excellent light-curve information. In addition, we have obtained 397 spectra of low-redshift SNe through a multiple-decade effort at Lick and Keck Observatories, and we have used 45 ultraviolet spectra obtained by HST/IUE. The low-redshift spect… more
Date: February 13, 2008
Creator: Foley, Ryan J.; Filippenko, Alexei V.; Aguilera, C.; Becker, A. C.; Blondin, S.; Challis, P. et al.
Partner: UNT Libraries Government Documents Department
open access

Observation of B0 -> chi_c0 K*0 and Evidence of B+ -> chi_c0 K*+

Description: The authors present the observation of the decay B{sup 0} {yields} {chi}{sub c0}K*{sup 0} as well as evidence of B{sup +} {yields} {chi}{sub c0}K*{sup +}, with an 8.9 and a 3.6 standard deviation significance, respectively, using a data sample of 454 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II B meson factory located at the Standard Linear Accelerator Center (SLAC). The measured branching fractions are: {Beta}(B{sup 0} {yields} {chi}{sub c0}K*{… more
Date: August 13, 2008
Creator: Aubert, B.
Partner: UNT Libraries Government Documents Department
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