Benchmark Studies of Induced Radioactivity Produced in LHC Materials, Pt I: Remanent Dose Rates (open access)

Benchmark Studies of Induced Radioactivity Produced in LHC Materials, Pt I: Remanent Dose Rates

Samples of materials which will be used in the LHC machine for shielding and construction components were irradiated in the stray radiation field of the CERN-EU high-energy reference field facility. After irradiation, the specific activities induced in the various samples were analyzed with a high-precision gamma spectrometer at various cooling times, allowing identification of isotopes with a wide range of half-lives. Furthermore, the irradiation experiment was simulated in detail with the FLUKA Monte Carlo code. A comparison of measured and calculated specific activities shows good agreement, supporting the use of FLUKA for estimating the level of induced activity in the LHC.
Date: April 12, 2006
Creator: Brugger, M.; Mayer, S.; Roesler, S.; Ulrici, L.; Khater, H.; Prinz, A. et al.
Object Type: Article
System: The UNT Digital Library
Benchmark Studies of Induced Radioactivity Produced in LHC Materials, Pt II Specific Activities (open access)

Benchmark Studies of Induced Radioactivity Produced in LHC Materials, Pt II Specific Activities

A new method to estimate remanent dose rates, to be used with the Monte Carlo code FLUKA, was benchmarked against measurements from an experiment that was performed at the CERN-EU high-energy reference field facility. An extensive collection of samples of different materials were placed downstream of and laterally to a copper target, intercepting a positively charged mixed hadron beam with a momentum of 120 GeV/c. Emphasis was put on the reduction of uncertainties such as careful monitoring of the irradiation parameters, the use of different instruments to measure dose rates, detailed elemental analyses of the irradiated materials and detailed simulations of the irradiation experiment. Measured and calculated dose rates are in good agreement.
Date: April 12, 2006
Creator: Brugger, M.; Mayer, S.; Roesler, S.; Ulrici, L.; Khater, H.; Prinz, A. et al.
Object Type: Article
System: The UNT Digital Library
The Endangered Species Act (ESA) in the 109th Congress: Conflicting Values and Difficult Choices (open access)

The Endangered Species Act (ESA) in the 109th Congress: Conflicting Values and Difficult Choices

This report discusses various proposals to amend the Endangered Species Act of 1973 (ESA; P.L. 93-205, 16 U.S.C. §§1531-1543). Major issues include changing the role of science in decision-making, modifying critical habitat (CH) procedures, reducing conflicts with Department of Defense activities, incorporating further protection and incentives for property owners, and increasing protection of listed species, among others.
Date: April 12, 2006
Creator: Buck, Eugene H.; Corn, M. Lynne; Sheikh, Pervaze A.; Baldwin, Pamela & Meltz, Robert
Object Type: Report
System: The UNT Digital Library
Pandemic Flu and Medical Biodefense Countermeasure Liability Legislation: P.L. 109-148, Division C (2005) (open access)

Pandemic Flu and Medical Biodefense Countermeasure Liability Legislation: P.L. 109-148, Division C (2005)

None
Date: April 12, 2006
Creator: Cohen, Henry
Object Type: Report
System: The UNT Digital Library
SRAT/SME Vessel (open access)

SRAT/SME Vessel

The Defense Waste Processing Facility (DWPF), at the Savannah River Site (SRS), is processing and immobilizing the radioactive high level waste sludge slurry at SRS into a durable borosilicate glass for final geological disposal. Each time a new batch of radioactive sludge is to be processed by the DWPF, the process flow sheet is to be tested and demonstrated to ensure an acceptable melter feed and glass can be made. These demonstrations are completed in the Shielded Cells Facility in the Savannah River National Laboratory at SRS.
Date: April 12, 2006
Creator: DOBOS, J
Object Type: Report
System: The UNT Digital Library
Sudan: Humanitarian Crisis, Peace Talks, Terrorism, and U.S. Policy (open access)

Sudan: Humanitarian Crisis, Peace Talks, Terrorism, and U.S. Policy

None
Date: April 12, 2006
Creator: Dagne, Ted
Object Type: Report
System: The UNT Digital Library
Gas Transport and Control in Thick-Liquid Inertial Fusion PowerPlants (open access)

Gas Transport and Control in Thick-Liquid Inertial Fusion PowerPlants

None
Date: April 12, 2006
Creator: Debonnel, Christophe Sylvain
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Hose Instability and Wake Generation By An Intense Electron Beam in a Self-Ionized Gas (open access)

Hose Instability and Wake Generation By An Intense Electron Beam in a Self-Ionized Gas

The propagation of an intense relativistic electron beam through a gas that is self-ionized by the beam's space charge and wakefields is examined analytically and with 3D particle-in-cell simulations. Instability arises from the coupling between a beam and the offset plasma channel it creates when it is perturbed. The traditional electron hose instability in a preformed plasma is replaced with this slower growth instability depending on the radius of the ionization channel compared to the electron blowout radius. A new regime for hose stable plasma wakefield acceleration is suggested.
Date: April 12, 2006
Creator: Deng, S.; Barnes, C. D.; Clayton, C. E.; O'Connell, C.; Decker, F. J.; Fonseca, R. A. et al.
Object Type: Article
System: The UNT Digital Library
Environmental Protection Issues in the 109th Congress (open access)

Environmental Protection Issues in the 109th Congress

This report gives an overview of key environmental issues receiving attention in the 109th Congress.
Date: April 12, 2006
Creator: Fletcher, Susan R. & Isler, Margaret
Object Type: Report
System: The UNT Digital Library
Babar: Sin(2beta) With Charm (open access)

Babar: Sin(2beta) With Charm

We present measurements of time-dependent CP asymmetries of neutral B decays to several charm and charmonium final states. Data have been collected with the BABAR detector at the PEP-II storage ring at the Stanford Linear Accelerator Center. In the absence of penguin contribution, the Standard Model predicts the time-dependent CP asymmetry parameters S and C are to be {eta}{sub CP} sin(2{beta}) and 0, respectively.
Date: April 12, 2006
Creator: Grenier, P. & U., /Ecole Polytechnique /Clermont-Ferrand
Object Type: Article
System: The UNT Digital Library
Report of the Event Tag Review and Recommendation Group (open access)

Report of the Event Tag Review and Recommendation Group

In order to facilitate access to the large volumes of data (multiple petabytes per year) which will be produced during data taking and Monte Carlo production at ATLAS, work has proceeded on building a system of event-level metadata to allow selections of a subset of events to use as input to an analysis. This was included in the ATLAS Computing Model and was first studied and implemented by the Physics Analysis Tools group based on the decisions of the ESD/AOD Task Force. They used tools developed and supported by the CERN IT group and the ATLAS Database group. During 2005 this structure was put through various tests and evaluations. Also, work by physicists on reconstruction and analysis led to an improved understanding of the requirements on the TAG. This report addresses the effect of these new inputs on the previous work with regard to content and the infrastructure needed to support it.
Date: April 12, 2006
Creator: Group, ATLAS; Assamagan, Kétévi A.; Barberis, Dario; Bentvelsen, Stan; Brooijmans, Gustaaf; Cranmer, Kyle et al.
Object Type: Article
System: The UNT Digital Library
MOTIVATION, DESCRIPTION, AND SUMMARY STATUS OF GEOMECHANICAL AND GEOCHEMICAL MODELING STUDIES IN TASK D OF THE INTERNATIONAL DECOVALEX-THMC PROJECT (open access)

MOTIVATION, DESCRIPTION, AND SUMMARY STATUS OF GEOMECHANICAL AND GEOCHEMICAL MODELING STUDIES IN TASK D OF THE INTERNATIONAL DECOVALEX-THMC PROJECT

None
Date: April 12, 2006
Creator: J.T. Birkholzer, D. Barr, J. Rutqvist, E. Sonnenthal
Object Type: Article
System: The UNT Digital Library
LCLS XTOD Attenuator System System Concept Report (open access)

LCLS XTOD Attenuator System System Concept Report

The attenuator system for the Linac Coherent Light Source (LCLS) X-ray Transport, Optics and Diagnostics (XTOD) system has been configured and analyzed by the Lawrence Livermore National Laboratory's New Technologies Engineering Division (NTED) as requested by the SLAC/LCLS program. The system layout, performance analyses and selection of the vacuum components are presented in this System Conceptual Review (SCR) report. Also included are the plans for prototype, procurement, mechanical integration, and the cost estimates.
Date: April 12, 2006
Creator: Kishiyama, K.; Roeben, M.; Trent, J.; Ryutov, D. & Shen, S.
Object Type: Report
System: The UNT Digital Library
Pressure-Induced Antifluorite-to-Anticotunnite Phase Transition in Lithium Oxide (open access)

Pressure-Induced Antifluorite-to-Anticotunnite Phase Transition in Lithium Oxide

Using synchrotron angle-dispersive x-ray diffraction (ADXD) and Raman spectroscopy on samples of Li{sub 2}O pressurized in a diamond anvil cell, we observed a reversible phase change from the cubic antifluorite ({alpha}, Fm-3m) to orthorhombic anticotunnite ({beta}, Pnma) phase at 50({+-}5) GPa at ambient temperature. This transition is accompanied by a relatively large volume collapse of 5.4 ({+-}0.8)% and large hysteresis upon pressure reversal (P{sub down} at {approx} 25 GPa). Contrary to a recent study, our data suggest that the high-pressure {beta}-phase (B{sub o} = 188 {+-} 12 GPa) is substantially stiffer than the low-pressure {alpha}-phase (B{sub o} = 90 {+-} 1 GPa). A relatively strong and pressure-dependent preferred orientation in {beta}-Li{sub 2}O is observed. The present result is in accordance with the systematic behavior of antifluorite-to-anticotunnite phase transitions occurring in the alkali-metal sulfides.
Date: April 12, 2006
Creator: Lazicki, A.; Yoo, C.; Evans, W. J. & Pickett, W. E.
Object Type: Article
System: The UNT Digital Library
The Effect of Ring Substitution Position on the Structural Conformation of Mercaptobenzoic Acid Self-Assembled Monolayers on Au(111) (open access)

The Effect of Ring Substitution Position on the Structural Conformation of Mercaptobenzoic Acid Self-Assembled Monolayers on Au(111)

Near edge X-ray absorption fine structure (NEX-AFS) spectroscopy, photoemission spectroscopy (PES) and contact angle measurements have been used to examine the structure and bonding of self-assembled monolayers (SAMs) prepared on Au(111) from the positional isomers of mercaptobenzoic acid (MBA). The isomer of MBA and solvent chosen in SAM preparation has considerable bearing upon film morphology. Carbon K-edge NEXAFS measurements indicate that the monomers of 2-, 3- and 4-MBA have well-defined orientations within their respective SAMs. Monomers of 3- and 4-MBA assume an upright orientation on the Au substrates in monolayers prepared using an acetic acid in ethanol solvent. The aryl ring and carboxyl group of these molecules are tilted from the surface normal by a colatitudal angle of {approx} 30{sup o}. Preparation of 4-MBA SAMs using pure ethanol solvent, a more traditional means of synthesis, had no appreciable effect upon the monomer orientation. Nonetheless, S(2p) PES measurements illustrate that it results in extensive bilayer formation via carboxyl group hydrogen-bonding between 4-MBA monomers. In 2-MBA monolayers prepared using acetic acid/ethanol solvent, the monomers adopt a more prostrate orientation on the Au substrates, in which the aryl ring and carboxyl group of the molecules are tilted {approx} 50{sup o} from the surface …
Date: April 12, 2006
Creator: Lee, J.; Willey, T.; Nilsson, J.; Terminello, L.; De Yoreo, J. & van Buuren, T.
Object Type: Article
System: The UNT Digital Library
An Exact Solution of Transport in Porous Media with Equilibrium and Kinetic Reactions (open access)

An Exact Solution of Transport in Porous Media with Equilibrium and Kinetic Reactions

This paper presents an analytical solution of reactive transport with equilibrium and kinetic reactions. A benchmark model of A {leftrightarrow} B {leftrightarrow} C {yields} chain reactions is developed for the purpose of verifying numerical computer codes and qualifying mathematical models. A reaction matrix is derived for both the equilibrium and first-order kinetic reactions and further decoupled as a diagonal matrix. Therefore, the partial differential equations (PDEs) coupled by the reaction matrix can be transformed into independent PDEs, for which closed-form solutions exist or can be derived. The analytical solution derived in this paper is compared with numerical results.
Date: April 12, 2006
Creator: Lu, X. & Sun, Y.
Object Type: Article
System: The UNT Digital Library
Effects of Test Temperature on Flow of Metallic Glasses (open access)

Effects of Test Temperature on Flow of Metallic Glasses

Micro-hardness experiments were conducted over a range of temperatures using a Nikon QM micro-hardness machine on a number of metallic glass (e.g. Zr-, Fe-, Al-) systems. Although high micro-hardness was exhibited at room temperature, significant hardness reductions were exhibited near the glass transition temperature, T{sub g}. The effects of changes in test temperature on the micro-hardness will be reported. The effects of exposure time on the hardness evolution at a given temperature will also be summarized to illustrate some of the differences in behavior of the systems shown. The extreme softening near T{sub g}, characteristic of bulk metallic glass systems, enables the exploration of novel deformation processing. In order to develop deformation processing windows, the evaluation of bulk metallic glass mechanical properties under quasi-static conditions and the determination of flow properties at different temperatures and strain rates are reported. The use of such information to create layered/composite bulk metallic glasses will be summarized.
Date: April 12, 2006
Creator: Nouri, A. S.; Liu, Y.; Wesseling, P. & Lewandowski, J.
Object Type: Report
System: The UNT Digital Library
Navy Ship Propulsion Technologies: Options for Reducing Oil Use - Background for Congress (open access)

Navy Ship Propulsion Technologies: Options for Reducing Oil Use - Background for Congress

None
Date: April 12, 2006
Creator: O'Rourke, Ronald
Object Type: Report
System: The UNT Digital Library
Two-Sided Pyramid Wavefront Sensor in the Direct Phase Mode (open access)

Two-Sided Pyramid Wavefront Sensor in the Direct Phase Mode

The two-sided pyramid wavefront sensor has been extensively simulated in the direct phase mode using a wave optics code. The two-sided pyramid divides the focal plane so that each half of the core only interferes with the speckles in its half of the focal plane. A relayed image of the pupil plane is formed at the CCD camera for each half. Antipodal speckle pairs are separated so that a pure phase variation causes amplitude variations in the two images. The phase is reconstructed from the difference of the two amplitudes by transforming cosine waves into sine waves using the Hilbert transform. There are also other corrections which have to be applied in Fourier space. The two-sided pyramid wavefront sensor performs extremely well: After two or three iterations, the phase error varies purely in y. The two-sided pyramid pair enables the phase to be completely reconstructed. Its performance has been modeled closed loop with atmospheric turbulence and wind. Both photon noise and read noise were included. The three-sided and four-sided pyramid wavefront sensors have also been studied in direct phase mode. Neither performs nearly as well as does the two-sided pyramid wavefront sensor.
Date: April 12, 2006
Creator: Phillion, D & Baker, K
Object Type: Article
System: The UNT Digital Library
Fabrication Effecrs on the Corrosion Behavior of Alloy 22 (open access)

Fabrication Effecrs on the Corrosion Behavior of Alloy 22

None
Date: April 12, 2006
Creator: Rebak, Raul B.
Object Type: Article
System: The UNT Digital Library
Explosion Source Phenomena Using Soviet, Test-Era, Waveform Data (open access)

Explosion Source Phenomena Using Soviet, Test-Era, Waveform Data

During the nuclear testing era, the former Soviet Union carried out extensive observations of underground nuclear explosions, recording both their own shots and those of foreign nuclear states. Between 1961 and 1989, the Soviet Complex Seismological Expedition deployed seismometers at time-varying subsets of over 150 sites to record explosions at regional distances from the Semipalatinsk and Lop Nor test sites and from the shot points of peaceful nuclear explosions. This data set included recordings from broadband, multi-channel ChISS seismometers that produced a series of narrow band outputs, which could then be measured to perform spectral studies. [ChISS is the Russian abbreviation for multichannel spectral seismometer. In this instrument the signal from the seismometer is passed through a system of narrow bandpass filters and recorded on photo paper. ChISS instruments have from 8 to 16 channels in the frequency range from 100 sec to 40 Hz. We used data mostly from 7 channels, ranging from 0.08 to 5 Hz.] Quantitative, pre-digital era investigations of high-frequency source scaling relied on this type of data. To augment data sets of central Central Asia explosions, we have measured and compiled 537 ChISS coda envelopes for 124 events recorded at Talgar, Kazakhstan, at a distance …
Date: April 12, 2006
Creator: Richards, Paul G.; Rautian, Tatyana G.; Khalturin, Vitaly I. & Phillips, W. Scott
Object Type: Report
System: The UNT Digital Library
Legislative Approaches to Chemical Facility Security (open access)

Legislative Approaches to Chemical Facility Security

This report discusses current chemical facility security efforts, issues in defining chemical facilities, policy challenges in developing chemical facility security legislation, and the various policy approaches.
Date: April 12, 2006
Creator: Shea, Dana A.
Object Type: Report
System: The UNT Digital Library
Iran's Nuclear Program: Recent Developments (open access)

Iran's Nuclear Program: Recent Developments

This report examines various issues regard Iran and its nuclear program.International Atomic Energy Agency (IAEA) inspections since 2003 have revealed two decades’ worth of undeclared nuclear activities in Iran, including uranium enrichment and plutonium separation efforts. Iran agreed in 2003 to suspend its enrichment and reprocessing activities in exchange for promises of assistance from Germany, France, and the UK (EU-3), but negotiations broke down in August 2005. On September 24, 2005, the IAEA Board of Governors found Iran to be in noncompliance with its Nuclear Nonproliferation Treaty (NPT) safeguards agreement (GOV/2005/77) and voted (GOV/2006/14) on February 4 to report Iran to the U.N. Security Council. The Security Council issued a presidential statement on March 29 that called upon Iran to reinstitute its voluntary suspension of enrichment and reprocessing and asked the IAEA to report on Iran’s compliance by April 28. On April 11, Iranian officials announced that they had enriched some uranium to 3.5% enrichment (fuel-grade).
Date: April 12, 2006
Creator: Squassoni, Sharon
Object Type: Report
System: The UNT Digital Library
Iraq's Nuclear Program: Recent Developments (open access)

Iraq's Nuclear Program: Recent Developments

This report discusses suspicions of an Iranian nuclear weapons program, and Iran’s current plans — to construct seven nuclear power plants (1000 MW each) by 2025.
Date: April 12, 2006
Creator: Squassoni, Sharon
Object Type: Report
System: The UNT Digital Library