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462 Matching Results

Start Over Year 2007 Day 4th

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Results: 1 - 24 of 462 next

(open access)

USING WET AIR OXIDATION TECHNOLOGY TO DESTROY TETRAPHENYLBORATE

A bench-scale feasibility study on the use of a Wet Air Oxidation (WAO) process to destroy a slurry laden with tetraphenylborate (TPB) compounds has been undertaken. WAO is an aqueous phase process in which soluble and/or insoluble waste constituents are oxidized using oxygen or oxygen in air at elevated temperatures and pressures ranging from 150 C and 1 MPa to 320 C and 22 MPa. The products of the reaction are CO{sub 2}, H{sub 2}O, and low molecular weight oxygenated organics (e.g. acetate, oxalate). Test results indicate WAO is a feasible process for destroying TPB, its primary daughter products [triphenylborane (3PB), diphenylborinic acid (2PB), and phenylboronic acid (1PB)], phenol, and most of the biphenyl byproduct. The required conditions are a temperature of 300 C, a reaction time of 3 hours, 1:1 feed slurry dilution with 2M NaOH solution, the addition of CuSO{sub 4}.5H{sub 2}O solution (500 mg/L Cu) as catalyst, and the addition of 2000 mL/L of antifoam. However, for the destruction of TPB, its daughter compounds (3PB, 2PB, and 1PB), and phenol without consideration for biphenyl destruction, less severe conditions (280 C and 1-hour reaction time with similar remaining above conditions) are adequate.

Date: April 4, 2007

Creator: Adu-Wusu, K; Daniel McCabe, D & Bill Wilmarth, B

Object Type: Article

System: The UNT Digital Library

(open access)

Topological Strings And (Almost) Modular Forms

The B-model topological string theory on a Calabi-Yau threefold X has a symmetry group {Lambda}, generated by monodromies of the periods of X. This acts on the topological string wave function in a natural way, governed by the quantum mechanics of the phase space H{sup 3}(X). We show that, depending on the choice of polarization, the genus g topological string amplitude is either a holomorphic quasi-modular form or an almost holomorphic modular form of weight 0 under {Lambda}. Moreover, at each genus, certain combinations of genus g amplitudes are both modular and holomorphic. We illustrate this for the local Calabi-Yau manifolds giving rise to Seiberg-Witten gauge theories in four dimensions and local IP{sub 2} and IP{sub 1} x IP{sub 1}. As a byproduct, we also obtain a simple way of relating the topological string amplitudes near different points in the moduli space, which we use to give predictions for Gromov-Witten invariants of the orbifold C{sub 3}/ZZ{sub 3}.

Date: May 4, 2007

Creator: Aganagic, Mina; Bouchard, Vincent & Klemm, Albrecht

Object Type: Article

System: The UNT Digital Library

(open access)

Luxury Town, U.S.A.: High-End Brands Expand, And Austin Gets a Makeover --- New Wealth, Galas Draw Tiffany, Louis Vuitton; Nieman's Black Tie Plan

Article published in the Wall Street Journal about the growth of high-end retail in Austin, Texas.

Date: September 4, 2007

Creator: Agins, Teri

Object Type: Article

System: The UNT Digital Library

(open access)

Laser heating of solid matter by light pressure-driven shocks

Heating by irradiation of a solid surface in vacuum with 5 x 10{sup 20} W cm{sup -2}, 0.8 ps, 1.05 {micro}m wavelength laser light is studied by x-ray spectroscopy of the K-shell emission from thin layers of Ni, Mo and V. A surface layer is heated to {approx} 5 keV with an axial temperature gradient of 0.6 {micro}m scale length. Images of Ni Ly{sub {alpha}} show the hot region has a {approx} 25 {micro}m diameter, much smaller than {approx} 70 {micro}m region of K{sub {alpha}} emission. 2D particle-in-cell (PIC) simulations suggest that the surface heating is due to a light pressure driven shock.

Date: May 4, 2007

Creator: Akli, K.; Hansen, S. B.; Kemp, A. J.; Freeman, R. R.; Beg, F. N.; Clark, D. et al.

Object Type: Article

System: The UNT Digital Library

(open access)

LCLS LLRF Upgrades to the SLAC Linac

The Linac Coherent Light Source (LCLS) at SLAC will be the brightest X-ray laser in the world when it comes on line. In order to achieve the brightness a 200fS length electron bunch is passed through an undulator. To create the 200fS, 3kA bunch, a 10pS electron bunch, created from a photo cathode in an RF gun, is run off crest on the RF to set up a position to energy correlation. The bunch is then compressed by chicanes. The stability of the RF system is critical in setting up the position to energy correlation. Specifications derived from simulations require the RF system to be stable to below 200fS in several critical injector stations and the last kilometer of linac. The SLAC linac RF system is being upgraded to meet these requirements.

Date: October 4, 2007

Creator: Akre, R.; Dowell, D.; Emma, P.; Frisch, J.; Hong, B.; Kotturi, K. et al.

Object Type: Article

System: The UNT Digital Library

(open access)

Timpson & Tenaha News (Timpson, Tex.), Vol. 22, No. 1, Ed. 1 Thursday, January 4, 2007

Weekly newspaper from Timpson, Texas that includes local, state, and national news along with advertising.

Date: January 4, 2007

Creator: Alexander, Nancy

Object Type: Newspaper

System: The Portal to Texas History

(open access)

Timpson & Tenaha News (Timpson, Tex.), Vol. 22, No. 40, Ed. 1 Thursday, October 4, 2007

Weekly newspaper from Timpson, Texas that includes local, state, and national news along with advertising.

Date: October 4, 2007

Creator: Alexander, Nancy

Object Type: Newspaper

System: The Portal to Texas History

(open access)

Age validation of canary rockfish (Sebastes pinniger) using two independent otolith techniques: lead-radium and bomb radiocarbon dating.

Canary rockfish (Sebastes pinniger) have long been an important part of recreational and commercial rockfish fishing from southeast Alaska to southern California, but localized stock abundances have declined considerably. Based on age estimates from otoliths and other structures, lifespan estimates vary from about 20 years to over 80 years. For the purpose of monitoring stocks, age composition is routinely estimated by counting growth zones in otoliths; however, age estimation procedures and lifespan estimates remain largely unvalidated. Typical age validation techniques have limited application for canary rockfish because they are deep dwelling and may be long lived. In this study, the unaged otolith of the pair from fish aged at the Department of Fisheries and Oceans Canada was used in one of two age validation techniques: (1) lead-radium dating and (2) bomb radiocarbon ({sup 14}C) dating. Age estimate accuracy and the validity of age estimation procedures were validated based on the results from each technique. Lead-radium dating proved successful in determining a minimum estimate of lifespan was 53 years and provided support for age estimation procedures up to about 50-60 years. These findings were further supported by {Delta}{sup 14}C data, which indicated a minimum estimate of lifespan was 44 {+-} 3 …

Date: November 4, 2007

Creator: Andrews, A H; Kerr, L A; Cailliet, G M; Brown, T A; Lundstrom, C C & Stanley, R D

Object Type: Article

System: The UNT Digital Library

(open access)

Cleanup Verification Package for the 118-F-3, Minor Construction Burial Ground

This cleanup verification package documents completion of remedial action for the 118-F-3, Minor Construction Burial Ground waste site. This site was an open field covered with cobbles, with no vegetation growing on the surface. The site received irradiated reactor parts that were removed during conversion of the 105-F Reactor from the Liquid 3X to the Ball 3X Project safety systems and received mostly vertical safety rod thimbles and step plugs.

Date: January 4, 2007

Creator: Appel, M. J.

Object Type: Report

System: The UNT Digital Library

(open access)

Metastable Vacua and D-branes at the Conifold

We consider quiver gauge theories arising on D-branes at simple Calabi-Yau singularities (quotients of the conifold). These theories have metastable supersymmetry breaking vacua. The field theoretic mechanism is basically the one exhibited by the examples of Intriligator, Seiberg and Shih in SUSY QCD. In a dual description, the SUSY breaking is captured by the presence of anti-branes. In comparison to our earlier related work, the main improvements of the present construction are that we can reach the free magnetic range of the SUSY QCD theory where the existence of the metastable vacua is on firm footing, and we can see explicitly how the small masses for the quark flavors (necessary to the existence of the SUSY breaking vacua) are dynamically stabilized. One crucial mass term is generated by a stringy instanton. Finally, our models naturally incorporate R-symmetry breaking in the non-supersymmetric vacuum, in a way similar to the examples of Kitano, Ooguri and Ookouchi.

Date: April 4, 2007

Creator: Argurio, Riccardo; Bertolini, Matteo; Franco, Sebastian & Kachru, Shamit

Object Type: Article

System: The UNT Digital Library

(open access)

Measurement of the B to Xs gammaBranching Fraction and Photon Energy Spectrum usingthe Recoil Method

We present a measurement of the branching fraction and photon energy spectrum for the decay B {yields} X{sub s}{gamma} using data from the BABAR experiment. The data sample corresponds to an integrated luminosity of 210 fb{sup -1}, from which approximately 680,000 B{bar B} events are tagged by a fully reconstructed hadronic decay of one of the B mesons. In the decay of the second B meson, an isolated high-energy photon is identified. We measure {Beta}(B {yields} X{sub s}{gamma}) = (3.66 {+-} 0.85{sub stat} {+-} 0.60{sub syst}) x 10{sup -4} for photon energies E{sub {gamma}} above 1.9 GeV in the B rest frame. From the measured spectrum we calculate the first and second moments for different minimum photon energies, which are used to extract the heavy-quark parameters m{sub b} and {mu}{sub {pi}}{sup 2}. In addition, measurements of the direct CP asymmetry and isospin asymmetry are presented.

Date: December 4, 2007

Creator: Aubert, B.

Object Type: Article

System: The UNT Digital Library

(open access)

Observation of Y(3940) to J/psi omega in B to J/psi omega K at BABAR

The authors report the results of a study of the decays B{sup +} {yields} J/{psi}{omega}K{sup +} and B{sup 0} {yields} J/{psi}{omega}K{sub S}{sup 0} using 383 million B{bar B} events from {Upsilon}(4S) decays with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} storage rings. They observe evidence for Y(3940) {yields} J/{psi}{omega} with product branching fractions {Beta}(B{sup +} {yields} Y K{sup +}, Y {yields} J/{psi}{omega}) = (4.9 {+-} 1.0(stat) {+-} 0.5(syst)) x 10{sup -5} and {Beta}(B{sup 0} {yields} Y K{sup 0}, Y {yields} J/{psi}{omega}) = (1.5{sub -1.2}{sup +1.4}(stat){sub -0.2}{sup +0.2}(syst)) x 10{sup -5}. The measured mass and width are M(Y) = (3914.6{sub -3.4}{sup +3.8}(stat){sub -1.9}{sup +1.9}(syst)) MeV/c{sup 2} and {Lambda}(Y) = (33{sub -8}{sup +12}(stat){sub -5}{sup +5}(syst)) MeV, respectively.

Date: December 4, 2007

Creator: Aubert, B.

Object Type: Article

System: The UNT Digital Library

$The e+e- to to K+ K- \pi+\pi-, K+ K- \pi0\pi0 and K+ K- K+ K- Cross Sections Measured with Initial-State Radiation$ (open access)

The e+e- to to K+ K- \pi+\pi-, K+ K- \pi0\pi0 and K+ K- K+ K- Cross Sections Measured with Initial-State Radiation

We study the processes e{sup +}e{sup -} {yields} K{sup +}K{sup -}{pi}{sup +}{pi}{sup -}{gamma}, K{sup +}K{sup -}{pi}{sup 0}{pi}{sup 0}{gamma} and K{sup +}K{sup -}K{sup +}K{sup -}{gamma}, where the photon is radiated from the initial state. About 34600, 4400 and 2300 fully reconstructed events respectively, are selected from 232 fb{sup -1} of BABAR data. The invariant mass of the hadronic final state defines the effective e{sup +}e{sup -} center-of-mass energy, so that the K{sup +}K{sup -}{pi}{sup +}{pi}{sup -}{gamma} data can be compared with direct measurements of the e{sup +}e{sup -} {yields} K{sup +}K{sup -}{pi}{sup +}{pi}{sup -}{gamma} reaction; no direct measurements exist for the e{sub +}e{sub -} {yields} K{sup +}K{sup -}{pi}{sup 0}{pi}{sup 0}{gamma} or e{sub +}e{sub -} {yields} K{sup +}K{sup -}K{sup +}K{sup -} reactions. Studying the structure of these events, we find contributions from a number of intermediate states, and we extract their cross sections where possible. In particular, we isolate the contribution from e{sup +}e{sup -} {yields} {phi}(1020)f{sub 0}(980) and study its structure near threshold. In the charmonium region, we observe the J/{psi} in all three final states and several intermediate states, as well as the {psi}/(2S) in some modes, and measure the corresponding branching fractions. We see no signal for the Y(4260) …

Date: May 4, 2007

Creator: Aubert, B.; Bona, M.; Boutigny, D.; Karyotakis, Y.; Lees, J. P.; Poireau, V. et al.

Object Type: Article

System: The UNT Digital Library

(open access)

Building America Best Practices Series, Volume 6: High-Performance Home Technologies: Solar Thermal & Photovoltaic Systems

This guide is was written by PNNL for the US Department of Energy's Building America program to provide information for residential production builders interested in building near zero energy homes. The guide provides indepth descriptions of various roof-top photovoltaic power generating systems for homes. The guide also provides extensive information on various designs of solar thermal water heating systems for homes. The guide also provides construction company owners and managers with an understanding of how solar technologies can be added to their homes in a way that is cost effective, practical, and marketable. Twelve case studies provide examples of production builders across the United States who are building energy-efficient homes with photovoltaic or solar water heating systems.

Date: June 4, 2007

Creator: Baechler, Michael C.; Gilbride, Theresa L.; Ruiz, Kathleen A.; Steward, Heidi E. & Love, Pat M.

Object Type: Report

System: The UNT Digital Library

(open access)

Multilayers for next generation x-ray sources

Multilayers are artificially layered structures that can be used to create optics and optical elements for a broad range of x-ray wavelengths, or can be optimized for other applications. The development of next generation x-ray sources (synchrotrons and x-ray free electron lasers) requires advances in x-ray optics. Newly developed multilayer-based mirrors and optical elements enabled efficient band-pass filtering, focusing and time resolved measurements in recent FLASH (Free Electron LASer in Hamburg) experiments. These experiments are providing invaluable feedback on the response of the multilayer structures to high intensity, short pulsed x-ray sources. This information is crucial to design optics for future x-ray free electron lasers and to benchmark computer codes that simulate damage processes.

Date: May 4, 2007

Creator: Bajt, S.; Chapman, H. N.; Spiller, E.; Hau-Riege, S.; Alameda, J.; Nelson, A. J. et al.

Object Type: Article

System: The UNT Digital Library

(open access)

Analytic Models of Plausible Gravitational Lens Potentials

Gravitational lenses on galaxy scales are plausibly modeled as having ellipsoidal symmetry and a universal dark matter density profile, with a Sersic profile to describe the distribution of baryonic matter. Predicting all lensing effects requires knowledge of the total lens potential: in this work we give analytic forms for that of the above hybrid model. Emphasizing that complex lens potentials can be constructed from simpler components in linear combination, we provide a recipe for attaining elliptical symmetry in either projected mass or lens potential.We also provide analytic formulae for the lens potentials of Sersic profiles for integer and half-integer index. We then present formulae describing the gravitational lensing effects due to smoothly-truncated universal density profiles in cold dark matter model. For our isolated haloes the density profile falls off as radius to the minus fifth or seventh power beyond the tidal radius, functional forms that allow all orders of lens potential derivatives to be calculated analytically, while ensuring a non-divergent total mass. We show how the observables predicted by this profile differ from that of the original infinite-mass NFW profile. Expressions for the gravitational flexion are highlighted. We show how decreasing the tidal radius allows stripped haloes to be modeled, …

Date: May 4, 2007

Creator: Baltz, Edward A.; Marshall, Phil & Oguri, Masamune

Object Type: Article

System: The UNT Digital Library

(open access)

Food Safety: Selected Issues and Bills in the 110th Congress

This report provides selected issues and bills in the 110th Congress related to Food Safety.

Date: September 4, 2007

Creator: Becker, GeoffreyS.

Object Type: Report

System: The UNT Digital Library

(open access)

The Colony Courier-Leader (The Colony, Tex.), Vol. 26, No. 9, Ed. 1 Wednesday, April 4, 2007

Weekly newspaper from The Colony, Texas that includes local, state, and national news along with advertising.

Date: April 4, 2007

Creator: Bick, Jack & Crimmins, Blaine

Object Type: Newspaper

System: The Portal to Texas History

(open access)

The Colony Courier-Leader (The Colony, Tex.), Vol. 26, No. 22, Ed. 1 Wednesday, July 4, 2007

Weekly newspaper from The Colony, Texas that includes local, state, and national news along with advertising.

Date: July 4, 2007

Creator: Bick, Jack & Crimmins, Blaine

Object Type: Newspaper

System: The Portal to Texas History

(open access)

Measurements of beta in B Decays to Charm and Charmonium at BaBar

In this article we will review recent BABAR measurements of Unitarity Triangle angle {beta} in B meson decays to charm and charmonium.

Date: October 4, 2007

Creator: Bomben, : M.

Object Type: Article

System: The UNT Digital Library

(open access)

Analytical Methods for Discriminating Stardust in Aerogel Capture Media

Comet 81P/Wild 2's serendipitous orbit change to the inner solar system in 1974 offered researchers a rare opportunity to sample cometary material from the Kuiper belt, a repository of material left over from solar system formation {approx}4.6 Gyr ago. NASA's Stardust mission intercepted the comet in January 2004 and returned with material collected from its tail in January 2006. The cometary material, consisting of particles ranging from 10 microns down to <2 nm, was collected in aerogel, a very low density ({approx}3 mg/cm cm3) silica foam, to minimize the effects of deceleration from 6.1 km/s. The entire deceleration track is extracted from the aerogel block as a pyramidal shape known as a keystone which can be mapped using x-ray fluorescence prior to extraction of terminal or intermediate particles for other analyses. One goal of the track mapping is to determine the bulk composition of the cometary material returned. Unfortunately, although the aerogel is predominantly SiO{sub 2}, there are sufficient quantities of trace elements similar to those expected in the cometary material to require sophisticated discrimination techniques in order to decide whether a fluorescence map pixel contains only aerogel or both aerogel and cometary material. We have developed a dual threshold …

Date: September 4, 2007

Creator: Brennan, S.; Ishii, H. A.; Bradley, J. P.; Luening, K.; Ignatyev, K. & Pianetta, P.

Object Type: Article

System: The UNT Digital Library