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Synthesis of the Five-Coordinate Ruthenium (II) Complexes [(PCP)Ru(CO)(L)][BAr'4] {PCP = 2,6-(CH2PtBu2)2 C6H3, BAr'4 = 3,5-(CF3)2C6H3, L= ɳ1-CICH2CI, ɳ 1-N2, or μ-Cl-Ru(PCP)(CO)}: Reactions with Phenyldiazomethane and Phenylacetylene (open access)

Synthesis of the Five-Coordinate Ruthenium (II) Complexes [(PCP)Ru(CO)(L)][BAr'4] {PCP = 2,6-(CH2PtBu2)2 C6H3, BAr'4 = 3,5-(CF3)2C6H3, L= ɳ1-CICH2CI, ɳ 1-N2, or μ-Cl-Ru(PCP)(CO)}: Reactions with Phenyldiazomethane and Phenylacetylene

Article discussing the synthesis of the five-coordinate ruthenium (II) complexes and reactions with phenyldiazomethane and phenylacetylene.
Date: October 6, 2005
Creator: Zhang, Jubo; Barakat, Khaldoon A.; Cundari, Thomas R., 1964-; Gunnoe, T. Brent; Boyle, Paul D.; Petersen, Jeffrey L. et al.
System: The UNT Digital Library
A T-Shaped Three-Coordinate Nickel(l) Carbonyl Complex and the Geometric Preferences of Three-Coordinate d9 Complexes (open access)

A T-Shaped Three-Coordinate Nickel(l) Carbonyl Complex and the Geometric Preferences of Three-Coordinate d9 Complexes

This article discusses a T-shaped three-coordinate nickel(l) carbonyl complex and the geometric preferences of three-coordinate d9 complexes.
Date: October 5, 2005
Creator: Eckert, Nathan A.; Dinescu, Adriana; Cundari, Thomas R., 1964- & Holland, Patrick L.
System: The UNT Digital Library
Comparative Plant Genomics Resources at Plant GDB (open access)

Comparative Plant Genomics Resources at Plant GDB

Article on comparative plant genomics resources at plant GDB.
Date: October 2005
Creator: Dong, Qunfeng; Lawrence, Carolyn J.; Schlueter, Shannon D.; Wilkerson, Matthew D.; Kurtz, Stefan; Brendel, Volker et al.
System: The UNT Digital Library
Effective dielectric constants of photonic crystal of aligned anisotropic cylinders and the optical response of a periodic array of carbon nanotubes (open access)

Effective dielectric constants of photonic crystal of aligned anisotropic cylinders and the optical response of a periodic array of carbon nanotubes

This article discusses effective dielectric constants of photonic crystal of aligned anisotropic cylanders and the optical response of a periodic array of carbon nanotubes.
Date: October 25, 2005
Creator: Reyes, E.; Krokhin, Arkadii A. & Roberts, James A.
System: The UNT Digital Library
The Effect of Ionizing Radiation U6+ Phases (open access)

The Effect of Ionizing Radiation U6+ Phases

None
Date: October 19, 2005
Creator: Utsunomiya, S. & Ewing, R. C.
System: The UNT Digital Library
Daily movements of female white-tailed deer relative to parturition and breeding. (open access)

Daily movements of female white-tailed deer relative to parturition and breeding.

Abstract: To assess how white-tailed deer (Odocoileus virginianus) herd demographics influence reproductive behaviors, we examined 24-h diel movements of female whitetailed deer relative to parturition and breeding in a low-density population with a near even sex ratio at the Savannah River Site (SRS), South Carolina. We conducted a series of intensive, 24-h radio-tracking periods of 13 females during spring and fall 2002. We compared daily range (ha), rate of travel (m/h), and distance between extreme daily locations (m), among the periods of pre-parturition and post-parturition and pre-, peak-, and post-rut. From pre-parturition to post-parturition, we observed decreases in diel range size (–38.2%), distance between extreme diel locations (–17.0%), and diel rate of travel (–18.2%). Diel range size, distance between extreme diel locations, and diel rate of travel during the pre-rut and rut exceeded those observed during post-rut. We further identified substantial increases in mobility during 12 24-h diel periods for eight females during our fall monitoring. Our data suggest that female white-tailed deer reduce mobility post-fawning following exaggerated movements during pre-parturition. Furthermore, despite a near equal sex ratio, estrous does may be required to actively seek potential mates due to low population density.
Date: October 1, 2005
Creator: D'Angelo, Gino J.; Comer, Christopher E.; Kilgo, John C.; Drennan, Cory D.; Osborn, David A. & Miller, Karl V.
System: The UNT Digital Library
RADIONUCLIDE DISPERSION RATES BY AEOLIAN, FLUVIAL, AND POROUS MEDIA TRANSPORT (open access)

RADIONUCLIDE DISPERSION RATES BY AEOLIAN, FLUVIAL, AND POROUS MEDIA TRANSPORT

None
Date: October 12, 2005
Creator: Walton, J.; P.Goodell; Beshears, C.; French, D. & Kelts, A.
System: The UNT Digital Library
INITIAL TEST WELL CONDITIONING AT NOPAL I URANIUM DEPOSIT, SIERRA PENA BLANCA, CHIHUAHUA, MEXICO (open access)

INITIAL TEST WELL CONDITIONING AT NOPAL I URANIUM DEPOSIT, SIERRA PENA BLANCA, CHIHUAHUA, MEXICO

None
Date: October 16, 2005
Creator: Oliver, R.D.; Dinsmoor, J.C.; Reyes-Cortes, I. & Aguilar, R. de la Garza
System: The UNT Digital Library
Expressions for the threshold current of multipass beam breakup in recirculating linacs from single cavity models (open access)

Expressions for the threshold current of multipass beam breakup in recirculating linacs from single cavity models

We investigate multipass beam breakup (BBU) in a recirculating linear accelerator in the framework of a single cavity model. We present expressions for the beam breakup threshold current for various situations derived from a perturbative solution of BBU equations. These formulae should serve as a guide to understand the BBU phenomenon for a particular system and also as a tool to estimate the BBU threshold current quickly. Many of the results presented are more general than previous considerations because they include the effects of coupling between the two transverse polarizations in each dipole higher order mode.
Date: October 1, 2005
Creator: Yunn, Byung C.
System: The UNT Digital Library
An Update on Reducing the Uncertainty in Solar Radiometric Measurements (open access)

An Update on Reducing the Uncertainty in Solar Radiometric Measurements

A presentation giving an update on reducing the uncertainty in solar radiometric measurements.
Date: October 1, 2005
Creator: Myers, D.; Reda, I.; Wilcox, S. & Lester, A.
System: The UNT Digital Library
Radiation Research Society 2005 Annual Meeting, Denver, Colorado (open access)

Radiation Research Society 2005 Annual Meeting, Denver, Colorado

Abstracts and proceedings of the 2005 Annual Meeting of the Radiation Research Society held in Denver, Colorado on October 16-19, 2005.
Date: October 4, 2005
Creator: Ullrich, Robert
System: The UNT Digital Library
Open and hidden charm production at RHIC and LHC (open access)

Open and hidden charm production at RHIC and LHC

We discuss aspects of open and hidden charm production in hadron-nucleus collisions at RHIC and LHC energies. We first discuss the extraction of the total charm cross section in lower energy collisions and how it compares to next-to-leading order quantum chromodynamics calculations. We then describe calculations of the transverse momentum distributions and their agreement with the shape of the measured STAR transverse momentum distributions. We next explain how shadowing and moderate nuclear absorption can explain the PHENIX J/{psi} dAu/pp ratios.
Date: October 12, 2005
Creator: Vogt, R.
System: The UNT Digital Library
A New Family of Transition Metal Nitrides (open access)

A New Family of Transition Metal Nitrides

The mechanical stability of platinum nitride has been studied using first-principles calculations. By calculating the single-crystal elastic constants, we show that platinum nitride can be stabilized in the fluorite structure, in which the nitrogen atoms occupy all the tetrahedral interstitial sites of the metal lattice. The stability is attributed to the pseudogap effect from analysis of the electronic structure.
Date: October 1, 2005
Creator: Yu, Rong & Zhang, Xiao-Feng
System: The UNT Digital Library
SCALING OF THE SUPERFLUID DENSITY IN HIGH-TEMPERATURE SUPERCONDUCTORS. (open access)

SCALING OF THE SUPERFLUID DENSITY IN HIGH-TEMPERATURE SUPERCONDUCTORS.

A scaling relation N{sub c} {approx} 4.4{sigma}{sub dc}T{sub c} has been observed parallel and perpendicular to the copper-oxygen planes in the high-temperature superconductors; N{sub c} is the spectral weight and {sigma}{sub dc} is the dc conductivity just above the critical temperature T{sub c}. In addition, Nb and Pb also fall close to the this scaling line. The application of the Ferrell-Glover-Tinkham sum rule to the BCS optical properties of Nb above and below T{sub c} yields N{sub c} {approx} 8.1{sigma}{sub dc}T{sub c} when the normal-state scattering rate is much greater than the superconducting energy gap (1/{tau} > 2{Delta}, the ''dirty'' limit). This result implies that the high-temperature superconductors may be in the dirty limit. The superconductivity perpendicular to the planes is explained by the Josephson effect, which again yields N{sub c} {approx} 8.1{sigma}{sub dc}T{sub c} in the BCS formalism. The similar forms for the scaling relation in these two directions suggests that in some regime the dirty limit and the Josephson effect may be viewed as equivalent.
Date: October 24, 2005
Creator: HOMES, C.C.
System: The UNT Digital Library
Local and Global Illumination in the Volume Rendering Integral (open access)

Local and Global Illumination in the Volume Rendering Integral

This article is intended as an update of the major survey by Max [1] on optical models for direct volume rendering. It provides a brief overview of the subject scope covered by [1], and brings recent developments, such as new shadow algorithms and refraction rendering, into the perspective. In particular, we examine three fundamentals aspects of direct volume rendering, namely the volume rendering integral, local illumination models and global illumination models, in a wavelength-independent manner. We review the developments on spectral volume rendering, in which visible light are considered as a form of electromagnetic radiation, optical models are implemented in conjunction with representations of spectral power distribution. This survey can provide a basis for, and encourage, new efforts for developing and using complex illumination models to achieve better realism and perception through optical correctness.
Date: October 21, 2005
Creator: Max, Nelson & Chen, Ming
System: The UNT Digital Library
CDF's Higgs sensitivity status (open access)

CDF's Higgs sensitivity status

The combined sensitivity of CDF's current Standard Model Higgs boson searches is presented. The expected 95% CL limits on the production cross section times the relevant Higgs boson branching ratios are computed for the W{sup {+-}}H {yields} {ell}{sup {+-}}{nu}b{bar b}, ZH {yields} {nu}{bar {nu}}b{bar b}, gg {yields} H {yields} W{sup +}W{sup -} W{sup {+-}}H {yields} W{sup {+-}}W{sup +}W{sup -} channels as they stand as of the October 2005, using results which were prepared for Summer 2005 conferences and a newer result form the gg {yields} H {yields} W{sup +}W{sup -} channel. Correlated and uncorrelated systematic uncertainties are taken into account, and the luminosity requirements for 95% CL exclusion, 3{sigma} evidence, and 5{sigma} discovery are computed for median experimental outcomes. A list of improvements required to achieve the sensitivity to a SM Higgs boson as quantified in the Higgs Sensitivity Working Group's report is provided.
Date: October 1, 2005
Creator: Junk, Tom
System: The UNT Digital Library
H Diffusion through Partially Internally Oxidized Pd-alloy Membranes (U) (open access)

H Diffusion through Partially Internally Oxidized Pd-alloy Membranes (U)

In 1998 Kirchheim et al remarked that ''to their knowledge, experimental results on the diffusion of hydrogen through multi-layers have not yet been reported'' [1]. Their research dealt with diffusion through ultra-thin multi-layers of Nb/Pd which they followed electrochemically using a time-lag method. Their results were somewhat uncertain in that no final conclusion about any effect of the internal interfaces could be reached. Very recently Yamakawa et al [2] investigated Pd/Fe and Pd/Ni multilayers at 378-625 K and found no strong influence of the interfaces, however, there was grain boundary diffusion for the Pd/Ni layers and retardation, possibly due to dislocation trapping. Takano et al [3] studied H diffusion through thin layers of Pd, Ni, or Cu deposited electrochemically on Fe and concluded that complications are introduced by thin films perhaps H trapping at vacancies as the thickness of the layer decreases to very small values. Holleck [4] measured H diffusion through mm thick Pd{sub 0.75}Ag{sub 0.25}/Ta/Pd{sub 0.75}Ag{sub 0.25} layers in the gas phase from 540-873 K and determined D{sub H,Ta} from the overall diffusion constant and the known D{sub H,alloy}; he concluded that the interface did not play a significant role at these temperatures. As in Holleck's, the present …
Date: October 1, 2005
Creator: Wang, D.; Flanagan, Ted B. & Shanahan, K. L.
System: The UNT Digital Library
Diamond Secondary Emitter (open access)

Diamond Secondary Emitter

We present the design and experimental progress on the diamond secondary emitter as an electron source for high average power injectors. The design criteria for average currents up to 1 A and charge up to 20 nC are established. Secondary Electron Yield (SEY) exceeding 200 in transmission mode and 50 in emission mode have been measured. Preliminary results on the design and fabrication of the self contained capsule with primary electron source and secondary electron emitter will also be presented.
Date: October 9, 2005
Creator: Ben-Zvi, Ilan; Rao, T.; Burrill, A.; Chang, X.; Grimes, J.; Rank, J. et al.
System: The UNT Digital Library
Optimizing Bandwidth Limited Problems Using One-SidedCommunication and Overlap (open access)

Optimizing Bandwidth Limited Problems Using One-SidedCommunication and Overlap

Partitioned Global Address Space languages like Unified Parallel C (UPC) are typically valued for their expressiveness, especially for computations with fine-grained random accesses. In this paper we show that the one-sided communication model used in these languages also has a significant performance advantage for bandwidth-limited applications. We demonstrate this benefit through communication microbenchmarks and a case-study that compares UPC and MPI implementations of the NAS Fourier Transform (FT) benchmark. Our optimizations rely on aggressively overlapping communication with computation but spreading communication events throughout the course of the local computation. This alleviates the potential communication bottleneck that occurs when the communication is packed into a single phase (e.g., the large all-to-all in a multidimensional FFT). Even though the new algorithms require more messages for the same total volume of data, the resulting overlap leads to speedups of over 1.75x and 1.9x for the two-sided and one-sided implementations, respectively, when compared to the default NAS Fortran/MPI release. Our best one-sided implementations show an average improvement of 15 percent over our best two-sided implementations. We attribute this difference to the lower software overhead of one-sided communication, which is partly fundamental to the semantic difference between one-sided and two-sided communication. Our UPC results use …
Date: October 14, 2005
Creator: Bell, Christian; Bonachea, Dan; Nishtala, Rajesh & Yelick, Katherine
System: The UNT Digital Library
Standard model and supersymmetric Higgs searches at CDF (open access)

Standard model and supersymmetric Higgs searches at CDF

We present the results on the searches for the SM and the MSSM Higgs boson production in proton-antiproton collisions at {radical}s = 1.96 GeV with the CDF detector. The Higgs bosons are searched for in various production and decay channels, with data samples corresponding to 400 pb{sup -1}. Using these measurements, we set an upper limit on the production cross section times branching fraction for the Standard Model Higgs as a function of the Higgs mass, and we obtain exclusion regions in the tan{beta} vs mass for the neutral MSSM Higgs, and branching fraction vs mass for the charged Higgs.
Date: October 1, 2005
Creator: Kilminster, Ben
System: The UNT Digital Library
Reactivity of Resorcinol Formaldehyde Resin with Nitric Acid (open access)

Reactivity of Resorcinol Formaldehyde Resin with Nitric Acid

Solid-state infrared spectroscopy, differential scanning calorimetry, and elemental analysis have been used to evaluate the reactivity of resorcinol formaldehyde resin with nitric acid and characterize the solid product. Two distinct reactions were identified within the temperature range 25-55 C. The first reaction is primarily associated with resin nitration, while the second involves bulk oxidation and degradation of the polymer network leading to dissolution and off-gassing. The threshold conditions promoting reaction have been identified. Reaction was confirmed with nitric acid concentrations as low as 3 M at 25 C applied temperature and 0.625 M at 66 C. Although a nitrated resin product can be isolated under appropriate experimental conditions, calorimetry testing indicates no significant hazard associated with handling the dry material.
Date: October 25, 2005
Creator: King, William D.; Fondeur, Fernando F.; Wilmarth, William R. & Pettis, Myra E.
System: The UNT Digital Library
Integration of Predicted Atmospheric Contaminant Plumes into ArcView GIS (open access)

Integration of Predicted Atmospheric Contaminant Plumes into ArcView GIS

The Savannah River National Laboratory (SRNL) plays a key role in emergency response scenarios in which there may be a release of atmospheric chemical or radiological contamination at the DOE's Savannah River Site (SRS). Meteorologists at SRNL use a variety of tools to predict the path of the plume and levels of contamination along the path. These predictions are used to guide field teams that take sample measurements for verification. Integration of these predicted plumes as well as field measurements into existing Geographic Information System (GIS) interactive maps provides key additional information for decision makers during an emergency. In addition, having this information in GIS format facilitates sharing the information with other agencies that use GIS. In order to be useful during an emergency, an application for converting predictions or measurements into GIS format must be automated and simple to use. Thus, a key design goal in developing such applications is ease of use. Simple menu selections and intuitive forms with graphical user interfaces are used to accomplish this goal. Applications have been written to convert two different predictive code results into ArcView GIS. Meteorologists at SRNL use the Puff/Plume code, which is tied to real-time wind data, to predict …
Date: October 10, 2005
Creator: Koffman, Larry D.
System: The UNT Digital Library
Inhibition of Chloride Induced Crevice Corrosion in Alloy 22 by Fluoride Ions (open access)

Inhibition of Chloride Induced Crevice Corrosion in Alloy 22 by Fluoride Ions

Alloy 22 (N06022) is highly resistant to localized corrosion. Alloy 22 may be susceptible to crevice corrosion in pure chloride (Cl{sup -}) solutions under aggressive environmental conditions. The effect of the fluoride (F{sup -}) over the crevice corrosion induced by chloride ions is still not well established. The objective of the present work was to explore the crevice corrosion resistance of this alloy to different mixtures of fluorides and chlorides. Cyclic potentiodynamic polarization (CPP) tests were conducted in deaerated aqueous solutions of pure halide ions and also in different mixtures of chloride and fluoride at 90 C and pH 6. The range of chloride concentration [Cl{sup -}] was 0.001 M {le} [Cl{sup -}] {le} 1 M and the range of molar fluoride to chloride ratio [F{sup -}]/[Cl{sup -}] was 0.1 {le} [F{sup -}]/[Cl{sup -}] {le} 10. Results showed that Alloy 22 was susceptible to crevice corrosion in all the pure chloride solutions but not in the pure fluoride solutions. Fluoride ions showed an inhibitor behavior only in mixtures with a molar ratio [F{sup -}]/[Cl{sup -}] > 2. For mixtures with a molar ratio [F{sup -}]/[Cl{sup -}] of 7 and 10 the inhibition of crevice corrosion was complete.
Date: October 9, 2005
Creator: Carranza, R M; Rodr?guez, M A & Rebak, R B
System: The UNT Digital Library
The ICF Status and Plans in the United States (open access)

The ICF Status and Plans in the United States

The United States continues to maintain its leadership in ICF as it moves toward the goal of ignition. The flagship of the program is the National Ignition Facility (NIF) presently under construction at LLNL. Experiments had begun on the first four beams of the National Ignition Facility just at the time of the last IFSA Conference. Several new successful campaigns have been conducted since then in planar hydrodynamics and hohlraums as well as activating the VISAR diagnostic for equation of state experiments. Highlights of these results will be reviewed. Presently, the four beam experimental capability has been suspended while the first eight beams are being installed as the first step in building out the project. Meanwhile, much progress has been made in developing ignition designs for using NIF. An array of designs having several ablator materials have been shown computationally to ignite with energies ranging from the design energy to as low as 1 MJ of laser energy. Alternative direct drive designs in the NIF indirect drive configuration have been developed by LLE. This wide array of design choices has increased the chance of achieving ignition sooner on the facility. Plans are now being developed to begin an ignition experimental …
Date: October 12, 2005
Creator: Moses, E.; Miller, G. & Kauffman, R.
System: The UNT Digital Library