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A 3D Parallel Beam Dynamics Code for Modeling High Brightness Beams in Photoinjectors (open access)

A 3D Parallel Beam Dynamics Code for Modeling High Brightness Beams in Photoinjectors

In this paper we report on IMPACT-T, a 3D beam dynamics code for modeling high brightness beams in photoinjectors and rf linacs. IMPACT-T is one of the few codes used in the photoinjector community that has a parallel implementation, making it very useful for high statistics simulations of beam halos and beam diagnostics. It has a comprehensive set of beamline elements, and furthermore allows arbitrary overlap of their fields. It is unique in its use of space-charge solvers based on an integrated Green function to efficiently and accurately treat beams with large aspect ratio, and a shifted Green function to efficiently treat image charge effects of a cathode. It is also unique in its inclusion of energy binning in the space-charge calculation to model beams with large energy spread. Together, all these features make IMPACT-T a powerful and versatile tool for modeling beams in photoinjectors and other systems. In this paper we describe the code features and present results of IMPACT-T simulations of the LCLS photoinjectors. We also include a comparison of IMPACT-T and PARMELA results.
Date: February 13, 2006
Creator: Qiang, Ji; Lidia, S.; Ryne, R.D. & Limborg, C.
Object Type: Article
System: The UNT Digital Library
The 9977 General Purpose Fissile Package, A Replacement for the 6M Specification Package (open access)

The 9977 General Purpose Fissile Package, A Replacement for the 6M Specification Package

General Purpose Fissile Package is a robust, single containment package capable of transporting plutonium and uranium metals and oxides.
Date: January 13, 2006
Creator: Smith, Allen
Object Type: Report
System: The UNT Digital Library
Access to Broadband Networks (open access)

Access to Broadband Networks

The purpose of this report is to provide a more concrete discussion of access to wireline broadband networks. To that end, this report provides a discussion of what broadband networks look like; how both consumers and independent applications providers gain access to these networks; and the parameters available to network providers (such as their choices about network architecture, overall bandwidth capacity, bandwidth reserved for their own use, traffic prioritization, the terms and rates for access to their networks and for their retail services) that can affect end users’ and independent applications providers’ access to those networks.
Date: December 13, 2006
Creator: Goldfarb, Charles B.
Object Type: Report
System: The UNT Digital Library
Adaptive Optics Imaging Survey of Luminous Infrared Galaxies (open access)

Adaptive Optics Imaging Survey of Luminous Infrared Galaxies

We present high resolution imaging observations of a sample of previously unidentified far-infrared galaxies at z < 0.3. The objects were selected by cross-correlating the IRAS Faint Source Catalog with the VLA FIRST catalog and the HST Guide Star Catalog to allow for adaptive optics observations. We found two new ULIGs (with L{sub FIR} {ge} 10{sup 12} L{sub {circle_dot}}) and 19 new LIGs (with L{sub FIR} {ge} 10{sup 11} L{sub {circle_dot}}). Twenty of the galaxies in the sample were imaged with either the Lick or Keck adaptive optics systems in H or K{prime}. Galaxy morphologies were determined using the two dimensional fitting program GALFIT and the residuals examined to look for interesting structure. The morphologies reveal that at least 30% are involved in tidal interactions, with 20% being clear mergers. An additional 50% show signs of possible interaction. Line ratios were used to determine powering mechanism; of the 17 objects in the sample showing clear emission lines--four are active galactic nuclei and seven are starburst galaxies. The rest exhibit a combination of both phenomena.
Date: March 13, 2006
Creator: Laag, E. A.; Canalizo, G.; van Breugel, W.; Gates, E. L.; de Vries, W. & Stanford, S. A.
Object Type: Article
System: The UNT Digital Library
Adsorption and Precipitation of Aqueous Zn(II) on Hematite Nano- and Microparticles (open access)

Adsorption and Precipitation of Aqueous Zn(II) on Hematite Nano- and Microparticles

As part of a study of the effect of particle size on reactivity of hematite to aqueous metal ions, the sorption of Zn(II) on hematite nanoparticles and microparticles was examined over a wide range of Zn(II) concentrations using Zn K-edge EXAFS. When reacted with nanoparticles at pH 5.5 and low Zn(II) sorption densities (0.04 {le} {Lambda} < 2.76 imol/m{sup 2}), Zn(II) formed five-coordinated or a mixture of four- and six-coordinated surface complexes with an average Zn-O distance of 2.04({+-}0.02){angstrom}. At pH 5.5 and high Zn(II) sorption densities (2.76 {ge} {Lambda} {le} 3.70 mol/m{sup 2}), formation of surface precipitates is suggested based on the presence of second-shell Zn and multiple scattering features in the Fourier transform (FT) of the EXAFS spectra. EXAFS fitting of these high {Lambda} samples yielded an average first-shell Zn-O distance of 2.10({+-}0.02){angstrom}, with second-shell Zn-Fe and Zn-Zn distances of 3.23({+-}0.03){angstrom} and 3.31({+-}0.03){angstrom}, respectively. Qualitative comparison between the EXAFS spectra of these sorption samples and that of amorphous zinc hydroxide and Zn-bearing hydrotalcite indicates the development of surface precipitates with increasing {Lambda}. EXAFS spectra of Zn(II) sorbed on hematite microparticles under similar experimental conditions showed no evidence for surface precipitates even at the highest Zn surface coverage ({Lambda} …
Date: December 13, 2006
Creator: Ha, Juyong; /Stanford U., Geo. Environ. Sci.; Farges, Francois; /Stanford U., Geo. Environ. Sci. /Museum Nat. Hist., Paris; Brown, Gordon E., Jr. & /SLAC, SSRL
Object Type: Article
System: The UNT Digital Library
Adsorption Mechanisms of Trivalent Gold onto Iron Oxy-Hydroxides: From the Molecular Scale to the Model (open access)

Adsorption Mechanisms of Trivalent Gold onto Iron Oxy-Hydroxides: From the Molecular Scale to the Model

Gold is a highly valuable metal that can concentrate in iron-rich exogenetic horizons such as laterites. An improved knowledge of the retention mechanisms of gold onto highly reactive soil components such as iron oxyhydroxides is therefore needed to better understand and predict the geochemical behavior of this element. In this study, we use EXAFS information and titration experiments to provide a realistic thermochemical description of the sorption of trivalent gold onto iron oxy-hydroxides. Analysis of Au L{sub III}-edge XAFS spectra shows that aqueous Au(III) adsorbs from chloride solutions onto goethite surfaces as inner-sphere square-planar complexes (Au(III)(OH,Cl){sub 4}), with dominantly OH ligands at pH > 6 and mixed OH/Cl ligands at lower pH values. In combination with these spectroscopic results, Reverse Monte Carlo simulations were used to constraint the possible sorption sites on the surface of goethite. Based on this structural information, we calculated sorption isotherms of Au(III) on Fe oxy-hydroxides surfaces, using the CD-MUSIC (Charge Distribution--Multi Site Complexation) model. The various Au(III)-sorbed species were identified as a function of pH, and the results of these EXAFS+CD-MUSIC models are compared with titration experiments. The overall good agreement between the predicted and measured structural models shows the potential of this combined approach …
Date: December 13, 2006
Creator: Cances, Benjamin; Benedetti, Marc; Farges, Francois; Brown, Gordon E., Jr. & /Stanford U., Geo. Environ. Sci. /SLAC, SSRL
Object Type: Article
System: The UNT Digital Library
Adventures in Laser Produced Plasma Research (open access)

Adventures in Laser Produced Plasma Research

In the UK the study of laser produced plasmas and their applications began in the universities and evolved to a current system where the research is mainly carried out at the Rutherford Appleton Laboratory Central Laser Facility ( CLF) which is provided to support the universities. My own research work has been closely tied to this evolution and in this review I describe the history with particular reference to my participation in it.
Date: January 13, 2006
Creator: Key, M.
Object Type: Book
System: The UNT Digital Library
The Advisory Panel's Tax Reform Proposals (open access)

The Advisory Panel's Tax Reform Proposals

In early 2005, the President appointed a tax reform advisory panel to formulate tax reform proposals. The report of the President’s Advisory Panel on Tax Reform, issued in November 2005, recommended two reform plans to consider: 1) a revised income tax, referred to as the simplified income tax (SIT); and 2) a consumption tax coupled with a tax on financial income, referred to as the growth and investment tax (GIT). This report discusses the provisions and implications of these two taxes in detail.
Date: July 13, 2006
Creator: Gravelle, Jane G.
Object Type: Report
System: The UNT Digital Library
AEGIS: The Diversity of Bright Near-IR Selected Distant RedGalaxies (open access)

AEGIS: The Diversity of Bright Near-IR Selected Distant RedGalaxies

We use deep and wide near infrared (NIR) imaging from the Palomar telescope combined with DEEP2 spectroscopy and Hubble Space Telescope (HST) and Chandra Space Telescope imaging to investigate the nature of galaxies that are red in NIR colors. We locate these 'distant red galaxies' (DRGs) through the color cut (J - K){sub vega} > 2.3 over 0.7 deg{sup 2}, where we find 1010 DRG candidates down to K{sub s} = 20.5. We combine 95 high quality spectroscopic redshifts with photometric redshifts from BRIJK photometry to determine the redshift and stellar mass distributions for these systems, and morphological/structural and X-ray properties for 107 DRGs in the Extended Groth Strip. We find that many bright (J - K){sub vega} > 2.3 galaxies with K{sub s} < 20.5 are at redshifts z < 2, with 64% between 1 < z < 2. The stellar mass distributions for these galaxies is broad, ranging from 10{sup 9} - 10{sup 12} M{sub {circle_dot}} , but with most z > 2 systems massive with M{sub *} > 10{sup 11} M{sub {circle_dot}}. HST imaging shows that the structural properties and morphologies of DRGs are also diverse, with the majority elliptical/compact (57%), and the remainder edge-on spirals (7%), …
Date: October 13, 2006
Creator: Conselice, C. J.; Newman, J. A.; Georgakakis, A.; Almaini, O.; Coil, A. L.; Cooper, M. C. et al.
Object Type: Article
System: The UNT Digital Library
Agricultural Issues in the 109th Congress (open access)

Agricultural Issues in the 109th Congress

A number of issues affecting U.S. agriculture are receiving attention in the 109th Congress. The conference agreement on the FY2006 omnibus budget reconciliation bill includes a net reduction in spending on U.S. Department of Agriculture (USDA) mandatory programs of $2.7 billion over five years, and the reauthorization of a dairy income support program. Other issues of importance to agriculture during the second session of the 109th Congress include the possible consideration of emergency farm disaster assistance; multilateral and bilateral trade negotiations; concerns about agroterrorism, food safety, and animal and plant diseases (e.g., “mad cow” disease and avian flu); high energy costs; environmental issues; agricultural marketing matters, and the reauthorization of the Commodity Futures Trading Commission. This report will be updated as significant developments ensue.
Date: January 13, 2006
Creator: Chite, Ralph M.
Object Type: Report
System: The UNT Digital Library
Air Quality: EPA’s 2006 Changes to the Particulate Matter (PM) Standard (open access)

Air Quality: EPA’s 2006 Changes to the Particulate Matter (PM) Standard

In order to better understand EPA’s actions, this report provides an analysis of the agency’s final 2006 revisions to the particulates NAAQS, and the estimated costs and benefits of the new standards and of a more stringent alternatives analyzed. The report concludes by highlighting concerns and issues raised regarding the revisions to the particulates standards, including those of the science advisory committee (Clean Air Scientific Advisory Committee, or CASAC), and actions in Congress.
Date: November 13, 2006
Creator: Esworthy, Robert & McCarthy, James E.
Object Type: Report
System: The UNT Digital Library
Alaska Native Allotments: Alternatives to Address Conflicts with Utility Rights-of-way (open access)

Alaska Native Allotments: Alternatives to Address Conflicts with Utility Rights-of-way

Testimony issued by the Government Accountability Office with an abstract that begins "In 1906, the Alaska Native Allotment Act authorized the Secretary of the Interior to allot individual Alaska Natives (Native) a homestead of up to 160 acres. The validity of some of Copper Valley Electric Association's (Copper Valley) rights-of-way within Alaska Native allotments is the subject of ongoing dispute; in some cases the allottees assert that Copper Valley's electric lines trespass on their land. The Department of the Interior's (Interior) Bureau of Land Management (BLM) and Bureau of Indian Affairs (BIA) are responsible for granting rights-of-way and handling disputes between allottees and holders of rights-of-way. This testimony is based on GAO's report, Alaska Native Allotments: Conflicts with Utility Rights-of-way Have Not Been Resolved through Existing Remedies (GAO-04-923, September 7, 2004). Specifically GAO determined (1) the number of conflicts between Native allotments and Copper Valley rights-of-way and the factors that contributed to these conflicts, (2) the extent to which existing remedies have been used to resolve these conflicts, and (3) what legislative alternatives, if any, could be considered to resolve these conflicts."
Date: September 13, 2006
Creator: United States. Government Accountability Office.
Object Type: Text
System: The UNT Digital Library
Alkaline Electrolysis Final Technical Report (open access)

Alkaline Electrolysis Final Technical Report

In this project, GE developed electrolyzer stack technologies to meet DOE’s goals for low cost electrolysis hydrogen. The main barrier to meeting the targets for electrolyzer cost was in stack assembly and construction. GE’s invention of a single piece or “monolithic” plastic electrolyzer stack reduces these costs considerably. In addition, GE developed low cost cell electrodes using a novel application of metal spray coating technology. Bench scale stack testing and cost modeling indicates that the DOE targets for stack capital cost and efficiency can be met by full-scale production of industrial electrolyzers incorporating GE’s stack technology innovations.
Date: July 13, 2006
Creator: Bourgeois, RIchard; Sanborn, Steven & Assimakopoulos, Eliot
Object Type: Report
System: The UNT Digital Library
The All-Wavelength Extended Groth Strip International Survey(AEGIS) Data Sets (open access)

The All-Wavelength Extended Groth Strip International Survey(AEGIS) Data Sets

In this the first of a series of Letters, we present a description of the panchromatic data sets that have been acquired in the Extended Groth Strip region of the sky. Our survey, the All-wavelength Extended Groth Strip International Survey (AEGIS), is intended to study the physical properties and evolutionary processes of galaxies at z{approx}1. It includes the following deep, wide-field imaging data sets: Chandra/ACIS X-ray (0.5-10 keV), GALEX ultraviolet (1200-2500 Angstroms), CFHT/MegaCam Legacy Survey optical (3600-9000 Angstroms), CFHT/CFH12K optical (4500-9000 Angstroms), Hubble Space Telescope/ACS optical (4400-8500 Angstroms), Palomar/WIRC near-infrared (1.2-2.2 {micro}m), Spitzer/IRAC mid-infrared (3.6-8.0 {micro}m), Spitzer/MIPS far-infrared (24-70 {micro}m), and VLA radio continuum (6-20 cm). In addition, this region of the sky has been targeted for extensive spectroscopy using the DEIMOS spectrograph on the Keck II 10 m telescope. Our survey is compared to other large multiwavelength surveys in terms of depth and sky coverage.
Date: October 13, 2006
Creator: Davis, M.; Guhathakurta, P.; Konidaris, N. P.; Newman, J. A.; Ashby, M. L. N.; Biggs, A. D. et al.
Object Type: Article
System: The UNT Digital Library
Allele-specific deposition of macroH2A1 in Imprinting Control Regions (open access)

Allele-specific deposition of macroH2A1 in Imprinting Control Regions

In the current study, we analyzed the deposition patterns of macroH2A1 at a number of different genomic loci located in X chromosome and autosomes. MacroH2A1 is preferentially deposited at methylated CpG CpG-rich regions located close to promoters. The macroH2A1 deposition patterns at the methylated CpG islands of several imprinted domains, including the Imprinting Control Regions (ICRs) of Xist, Peg3, H19/Igf2 Igf2, Gtl2/Dlk1, and Gnas domains, show consistent allele-specificity towards inactive, methylated alleles. The macroH2A1 deposition levels at the ICRs and other Differentially Methylated Regions (DMRs) of these domains are also either higher or comparable to those observed at the inactive X chromosome of female mammals. Overall, our results indicate that besides DNA methylation macroH2A1 is another epigenetic component in the chromatin of ICRs displaying differential association with two parental alleles.
Date: January 13, 2006
Creator: Choo, J H; Kim, J D; Chung, J H; Stubbs, L & Kim, J
Object Type: Article
System: The UNT Digital Library
Analogies Between Neutron and Gamma-Ray Imaging. (open access)

Analogies Between Neutron and Gamma-Ray Imaging.

Although the physics describing the interactions of neutrons with matter is quite different from that appropriate for hard x-rays and gamma rays, there are a number of similarities that allow analogous instruments to be developed for both types of ionizing radiation. A pinhole camera, for example, requires that the radiation obeys some form of geometrical optics, that a material can be found to absorb some of the radiation, and that a suitable position-sensitive detector can be built to record the spatial distribution of the incident radiation. Such conditions are met for photons and neutrons, even though the materials used are quite different. Neutron analogues of the coded-aperture gamma camera and the Compton camera have been demonstrated. Even though the Compton effect applies only to photons, neutrons undergo proton-recoil scattering that can provide similar directional information. There is also an analogy in the existence of an energy spectrum for the radiation used to produce the images, and which may allow different types of sources to be distinguished from each other and from background.
Date: August 13, 2006
Creator: Vanier, P. E.
Object Type: Article
System: The UNT Digital Library
Analysis of Data for Exports Regulated by the Department of Commerce (open access)

Analysis of Data for Exports Regulated by the Department of Commerce

Correspondence issued by the Government Accountability Office with an abstract that begins "In light of the September 2001 terror attacks, we were asked to examine the Department of Commerce's Bureau of Industry and Security's (BIS) dual-use export control system. We reported our findings in a June 26, 2006, report, saying that BIS has not systematically evaluated the overall effectiveness and efficiency of the dual-use export control system. Specifically, we reported that BIS has not conducted comprehensive analyses of available data about items that have actually been exported from the United States. We made several recommendations in that report, including that Commerce should use the available data to evaluate the system's effectiveness. Because we had difficulty obtaining data on actual exports from Commerce, we were unable to provide specific details about these data in time for our June 2006 report. We have since obtained the data and are now transmitting to Congress our analysis of the data for 2004 and 2005."
Date: November 13, 2006
Creator: United States. Government Accountability Office.
Object Type: Text
System: The UNT Digital Library
Analysis of KEK-ATF Optics And Coupling Using Orbit Response Matrix Analysis (open access)

Analysis of KEK-ATF Optics And Coupling Using Orbit Response Matrix Analysis

LOCO is a code for analysis of the linear optics in a storage ring based on the closed orbit response to steering magnets. The analysis provides information on focusing errors, BPM gain and rotation errors, and local coupling. Here, we report the results of an application of LOCO to the KEK-ATF. Although the analysis appears to have provided useful information on the optics of the machine, it appears that one of the main aims of the study--to reduce the vertical emittance by correcting the local coupling--was not successful, and we discuss some possible reasons for this.
Date: October 13, 2006
Creator: Wolski, A.; Nelson, J.; Ross, M.; Woodley, M. & Mishra, S.
Object Type: Report
System: The UNT Digital Library
ANALYSIS RESULTS FOR BUILDING 241 702-AZ A TRAIN (open access)

ANALYSIS RESULTS FOR BUILDING 241 702-AZ A TRAIN

This report presents the analyses results for three samples obtained under RPP-PLAN-28509, Sampling and Analysis Plan for Building 241 702-AZ A Train. The sampling and analysis was done in response to problem evaluation request number PER-2004-6139, 702-AZ Filter Rooms Need Radiological Cleanup Efforts.
Date: December 13, 2006
Creator: JB, DUNCAN; JM, FRYE; CA, COOKE; SW, LI & FJ, BROCKMAN
Object Type: Report
System: The UNT Digital Library
Animal Identification and Meat Traceability (open access)

Animal Identification and Meat Traceability

This report focuses on animal ID and, to a lesser extent, on meat traceability. However, traceability, and the somewhat different but related concepts of "identity prevention" and "product segregation," also pertain to other agricultural products and issues.
Date: July 13, 2006
Creator: Becker, Geoffrey S.
Object Type: Report
System: The UNT Digital Library
Antitrust Effect of Patent on Tying Product: Illinois Tool Works Inc. v. Independent Ink, Inc. (open access)

Antitrust Effect of Patent on Tying Product: Illinois Tool Works Inc. v. Independent Ink, Inc.

Antitrust law generally disfavors tying arrangements- those in which a vendor conditions the same of a desired product on the purchase of another product
Date: April 13, 2006
Creator: Rubin, Janice E.
Object Type: Report
System: The UNT Digital Library
API Requirements for Dynamic Graph Prediction (open access)

API Requirements for Dynamic Graph Prediction

Given a large-scale time-evolving multi-modal and multi-relational complex network (a.k.a., a large-scale dynamic semantic graph), we want to implement algorithms that discover patterns of activities on the graph and learn predictive models of those discovered patterns. This document outlines the application programming interface (API) requirements for fast prototyping of feature extraction, learning, and prediction algorithms on large dynamic semantic graphs. Since our algorithms must operate on large-scale dynamic semantic graphs, we have chosen to use the graph API developed in the CASC Complex Networks Project. This API is supported on the back end by a semantic graph database (developed by Scott Kohn and his team). The advantages of using this API are (i) we have full-control of its development and (ii) the current API meets almost all of the requirements outlined in this document.
Date: October 13, 2006
Creator: Gallagher, B. & Eliassi-Rad, T.
Object Type: Report
System: The UNT Digital Library
Application of a Dynamic Stress Theory to Pike Leaks (open access)

Application of a Dynamic Stress Theory to Pike Leaks

This report talks about Application of a Dynamic Stress Theory to Pike Leaks
Date: March 13, 2006
Creator: Leishear, Robert A.
Object Type: Article
System: The UNT Digital Library
Application of Neutron-Absorbing Structural-Amorphous Metal (SAM) Coatings for Spent Nuclear Fuel (SNF) Container to Enhance Criticality Safety Controls (open access)

Application of Neutron-Absorbing Structural-Amorphous Metal (SAM) Coatings for Spent Nuclear Fuel (SNF) Container to Enhance Criticality Safety Controls

Spent nuclear fuel contains fissionable materials ({sup 235}U, {sup 239}Pu, {sup 241}Pu, etc.). Neutron multiplication and the potential for criticality are enhanced by the presence of a moderator during cask loading in water, water incursion in accidents conditions during spent fuel storage or transport. To prevent nuclear criticality in spent fuel storage, transportation, and during disposal, neutron-absorbing materials (or neutron poisons, such as borated stainless steel, Boral{trademark}, Metamic{trademark}, Ni-Gd, and others) would have to be applied. The success in demonstrating that the High-Performance Corrosion-Resistant material (HPCRM) can be thermally applied as coating onto base metal to provide for corrosion resistance for many naval applications raises the interest in applying the HPCRM to USDOE/OCRWM spent fuel management program. The fact that the HPCRM relies on the high content of boron to make the material amorphous--an essential property for corrosion resistance--and that the boron has to be homogeneously distributed in the HPCRM qualify the material to be a neutron poison.
Date: November 13, 2006
Creator: Choi, J.; Lee, C.; Day, D.; Wall, M.; Saw, C.; MoberlyChan, W. et al.
Object Type: Article
System: The UNT Digital Library