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48Ti(n,xnypz ag) reactions for neutron energies up to 250 MeV (open access)

48Ti(n,xnypz ag) reactions for neutron energies up to 250 MeV

Cross section measurements were made of prompt {gamma}-ray production as a function of incident neutron energy on a {sup 48}Ti sample. Partial {gamma}-ray cross sections for transitions in {sup 45--48}Ti, {sup 44--48}Sc, {sup 42--45}Ca, {sup 41--44}K, and {sup 41--42}Ar have been determined. Energetic neutrons were delivered by the Los Alamos National Laboratory spallation neutron source located at the LANSCE/WNR facility. The prompt-reaction {gamma} rays were detected with the large-scale Compton-suppressed germanium array for neutron induced excitations (GEANIE). Neutron energies were determined by the time-of-flight technique. The {gamma}-ray excitation functions were converted to partial {gamma}-ray cross sections taking into account the dead-time correction, target thickness, detector efficiency and neutron flux (monitored with an in-line fission chamber). The data will be presented for neutron energies between 1 to 250 MeV. These results are compared with model calculations which include compound nuclear and pre-equilibrium emission.
Date: October 11, 2004
Creator: Dashdorj, D.; Garrett, P. E.; Becker, J. A.; Bernstein, L. A.; Cooper, J. R.; Devlin, M. et al.
Object Type: Article
System: The UNT Digital Library
Air Pollution: EPA Could Take Additional Steps to Help Maximize the Benefits from the 2007 Diesel Emissions Standards (open access)

Air Pollution: EPA Could Take Additional Steps to Help Maximize the Benefits from the 2007 Diesel Emissions Standards

A letter report issued by the General Accounting Office with an abstract that begins "Diesel engine emissions pose health risks, but one major source--heavy-duty diesel vehicles--is critical for our economy. To reduce risks, the Environmental Protection Agency (EPA) has set stringent emissions standards for diesel engines. In 1998, EPA found that some engine makers were violating standards, so they agreed to build engines that meet 2004 standards early, by October 2002. EPA has set even more stringent standards for 2007. GAO was asked to (1) assess the October 2002 deadline's effects on industry and emissions, and (2) obtain stakeholders' views on the readiness of technology for the 2007 standards and EPA's efforts to ensure this. GAO analyzed information from EPA, 10 large trucking companies, the engine makers subject to the early deadline, and other stakeholders."
Date: March 11, 2004
Creator: United States. General Accounting Office.
Object Type: Report
System: The UNT Digital Library
Amplification of Pressure Waves during Vibrational Equilibration of Excited Chemical Reaction Products (open access)

Amplification of Pressure Waves during Vibrational Equilibration of Excited Chemical Reaction Products

The Non-Equilibrium Zeldovich - von Neumann - Doring (NEZND) theory of self-sustaining detonation identified amplification of pressure wavelets during equilibration of vibrationally excited reaction products in the reaction zone as the physical mechanism by which exothermic chemical energy release sustains detonation waves. This mechanism leads to the formation of the well-known, complex three-dimensional structure of a self-sustaining detonation wave. This amplification mechanism is postulated to be a general property of subsonic and supersonic reactive flows occurring during: shock to detonation transition (SDT); hot spot ignition and growth; deflagration to detonation transition (DDT); flame acceleration by shock or compression waves; and acoustic (sound) wave amplification. The existing experimental and theoretical evidence for pressure wave amplification by chemical energy release into highly vibrationally excited product molecules under these reactive flow conditions is reviewed in this paper.
Date: May 11, 2004
Creator: Tarver, C M
Object Type: Article
System: The UNT Digital Library
Analysis of design tradeoffs for diplay case evaporators (open access)

Analysis of design tradeoffs for diplay case evaporators

A model for simulating a display case evaporator under frosting conditions has been developed, using a quasi-steady and finite-volume approach and a Newton-Raphson based solution algorithm. It is capable of simulating evaporators with multiple modules having different geometries, e.g. tube and fin thicknesses and pitch. The model was validated against data taken at two-minute intervals from a well-instrumented medium-temperature vertical display case, for two evaporators having very different configurations. The data from these experiments provided both the input data for the model and also the data to compare the modeling results. The validated model has been used to generate some general guidelines for coil design. Effects of various geometrical parameters were quantified, and compressor performance data were used to express the results in terms of total power consumption. Using these general guidelines, a new prototype evaporator was designed for the subject display case, keeping in mind the current packaging restrictions, tube and fin availabilities. It is an optimum coil for the given external load conditions. Subsequently, the validated model was used in a more extensive analysis to design prototype coils with some of the current tube and fin spacing restrictions removed. A new microchannel based suction line heat exchanger was …
Date: August 11, 2004
Creator: Bullard, CLARK
Object Type: Report
System: The UNT Digital Library
Application of Ab Initio and CALPHAD Thermodynamics to Mo-Ta-W Alloys (open access)

Application of Ab Initio and CALPHAD Thermodynamics to Mo-Ta-W Alloys

None
Date: October 11, 2004
Creator: Turchi, P. A.; Drchal, V.; Kudrnovsky, J.; Colinet, C.; Kaufman, L. & Liu, Z.
Object Type: Article
System: The UNT Digital Library
An Application of the Coda Methodology for Moment-Rate Spectra Using Broadband Stations in Turkey (open access)

An Application of the Coda Methodology for Moment-Rate Spectra Using Broadband Stations in Turkey

A recently developed coda magnitude methodology was applied to selected broadband stations in Turkey for the purpose of testing the coda method in a large, laterally complex region. As found in other, albeit smaller regions, coda envelope amplitude measurements are significantly less variable than distance-corrected direct wave measurements (i.e., L{sub g} and surface waves) by roughly a factor 3-to-4. Despite strong lateral crustal heterogeneity in Turkey, they found that the region could be adequately modeled assuming a simple 1-D, radially symmetric path correction. After calibrating the stations ISP, ISKB and MALT for local and regional distances, single-station moment-magnitude estimates (M{sub W}) derived from the coda spectra were in excellent agreement with those determined from multistation waveform modeling inversions, exhibiting a data standard deviation of 0.17. Though the calibration was validated using large events, the results of the calibration will extend M{sub W} estimates to significantly smaller events which could not otherwise be waveform modeled. The successful application of the method is remarkable considering the significant lateral complexity in Turkey and the simple assumptions used in the coda method.
Date: July 11, 2004
Creator: Eken Tuna, Kevin Mayeda, Abraham Hofstetter, Rengin Gok, Gonca Orgulu, Niyazi Turkelli
Object Type: Article
System: The UNT Digital Library
Archaeological Survey East of Prairie Creek, Dallas and Collin Counties, Texas (open access)

Archaeological Survey East of Prairie Creek, Dallas and Collin Counties, Texas

A report for a cultural resources survey for the proposed Huck Finn Trail to be placed east of Prairie Creek in Richardson, Texas.
Date: November 11, 2004
Creator: Todd, Jesse
Object Type: Report
System: The Portal to Texas History
Army Transformation and Modernization: Overview and Issues for Congress (open access)

Army Transformation and Modernization: Overview and Issues for Congress

This report briefly describes the modernization program for the U.S. military forces and discusses issues of feasibility, viability, and affordability of potential interest to Congress.
Date: March 11, 2004
Creator: Bruner, Edward F.
Object Type: Report
System: The UNT Digital Library
Asymmetric injection of cathodic arc plasma into a macroparticlefilter (open access)

Asymmetric injection of cathodic arc plasma into a macroparticlefilter

The cathodic arc plasmas produced by cathode spots usuallyinclude macroparticles, which is undesirable for many applications. Acommon way of removing macroparticles is to use curved solenoid filterswhich guide the plasma from the source to the substrate. In this work, anarc source with relatively small cathode is used, limiting the possiblelocations of plasma production. The relative position of cathodic arcsource and macroparticle filtered was systematically varied and thefiltered plasma current was recorded. It was found that axis-symmetricplasma injection leads to maximum throughput only if an anode aperturewas used, which limited the plasma to near-axis flow by scraping offplasma at larger angles to the axis. When the anode aperture was removed,more plasma could enter the filter. In this case, maximum filtered ioncurrent was achieved when the plasma was injected off-axis, namely offsetin the direction where the filter is curved. Such behavior wasanticipated because the plasma column in the filter is known to beshifted by ExB and centrifugal drift as well as by non-axis-symmetriccomponents of the magnetic field in the filter entrance and exit plane.The data have implications for plasma transport variations caused bydifferent spot locations on cathodes that are not small compared to thefilter cross section.
Date: February 11, 2004
Creator: Anders, Andre & MacGill, Robert A.
Object Type: Article
System: The UNT Digital Library
Atomic scale structure of the 5-fold surface of an AlPdMn quasicrystal: A quantitative X-Ray photoelectron diffraction analysis (open access)

Atomic scale structure of the 5-fold surface of an AlPdMn quasicrystal: A quantitative X-Ray photoelectron diffraction analysis

The atomic scale structure of the 5-fold symmetric surface of an AlPdMn quasicrystal is investigated quantitatively by comparing x-ray photoelectron diffraction (XPD) simulations to experiment. The observed 5-fold symmetry of the diffraction patterns indicates that the surface is quasicrystalline with no hint of a reconstruction from the bulk structure. In analyzing the experimental data, many possible bulk terminations have been tested. Those few that fit best to the data have in common that they contain an Al-rich surface layer followed by a dense mixed Al/Pd/Mn layer. These best terminations, while not identical to each other, are suggested to form terraces coexisting on a real surface. Structural relaxations of the quasicrystal surface are also analyzed: mixing several best-fit terminations gives average best-fit interlayer spacing changes of Dd12 = -0.057 Angstrom, Dd24 = +0.159 Angstrom. These results are in good agreement with a prior structure determination by LEED on a sample that was prepared in a different manner.
Date: February 11, 2004
Creator: Zheng, Jin-Cheng; Huan, C. H. A.; Wee, A. T. S.; Van Hove, M. A.; Fadley, C. S.; Shi, F. J. et al.
Object Type: Article
System: The UNT Digital Library
Beam diagnostics via model independent analysis of the turn-by-turn BPM data (open access)

Beam diagnostics via model independent analysis of the turn-by-turn BPM data

Model independent analysis (MIA) can be used to obtain all the eigen modes included in the turn-by-turn BPM data. Not only the synchrotron tune and betatron tune can be obtained from the fast Fourier transforms (FFT) of the temporal eigen vector of the corresponding mode, but also the error mode, which could be caused by the different gain of a BPM, can be observed in both the temporal and spatial eigen vectors of the error mode. It can be applied as a diagnostic tool for Booster.
Date: August 11, 2004
Creator: Yang, Xi
Object Type: Report
System: The UNT Digital Library
Bovine Enterovirus Type 2. Complete Genomic Sequence and Molecular Modeling of a Reference Strain and a Wild Type Isolate from Endemically Infected US Cattle. (open access)

Bovine Enterovirus Type 2. Complete Genomic Sequence and Molecular Modeling of a Reference Strain and a Wild Type Isolate from Endemically Infected US Cattle.

None
Date: February 11, 2004
Creator: Zhou, C E; Zemla, A; Goens, S D; Botero, S & Perdue, M L
Object Type: Article
System: The UNT Digital Library
Broadband Internet Access and the Digital Divide: Federal Assistance Programs (open access)

Broadband Internet Access and the Digital Divide: Federal Assistance Programs

Some policymakers, believing that disparities in broadband access across American society could have adverse economic and social consequences on those left behind, assert that the federal government should play a more active role to avoid a “digital divide” in broadband access. One approach is for the federal government to provide financial assistance to support broadband deployment in underserved areas. Others, however, believe that federal assistance for broadband deployment is not appropriate. Some opponents question the reality of the “digital divide,” and argue that federal intervention in the broadband marketplace would be premature and, in some cases, counterproductive.
Date: March 11, 2004
Creator: Kruger, Lennard G.
Object Type: Report
System: The UNT Digital Library
Colorimetric Method for Beryllium Surface Contamination Detection (open access)

Colorimetric Method for Beryllium Surface Contamination Detection

To address the need for real-time accurate total beryllium analyses, Savannah River Technology Center Analytical Development Section personnel evaluated and modified a colorimetric screening method developed at Los Alamos National Lab to measure beryllium on surfaces. This method was based on a color complex formed by beryllium and chromium azurol s . SRTC converted this visual method to a quantitative analysis method using spectrophotometric detection. The addition of a cationic surfactant (hexadecyltrimethylammonium bromide, CTAB) to the Be-CAS system shifted the complex absorbance away from the CAS absorbance and allowed for the detection. Assuming complete dissolution and a 10 mL rinse solution volume to remove the beryllium from the wipe, the detection limit was calculated comfortably below the free release limit. The spectrophotometric method was rugged and simple enough that it could be used as a field method.
Date: March 11, 2004
Creator: MCWHORTER, CHRISTOPHER
Object Type: Report
System: The UNT Digital Library
Commercial Aviation: Legacy Airlines Must Further Reduce Costs to Restore Profitability (open access)

Commercial Aviation: Legacy Airlines Must Further Reduce Costs to Restore Profitability

A letter report issued by the Government Accountability Office with an abstract that begins "Since 2001, the U.S. airline industry has confronted financial losses of previously unseen proportions. From 2001 to 2003, the industry lost $23 billion, and two of the nation's biggest airlines have gone into bankruptcy. To assist airlines, the Congress provided U.S. airlines with $7 billion of direct financial assistance--most recently in the form of $2.4 billion of financial assistance under the 2003 Emergency Wartime Supplemental Appropriations Act. Under the Act and its accompanying conference report, the conferees directed GAO to review measures taken by airlines to reduce costs, improve revenues and profits, and strengthen their balance sheets. The Congress also tasked airlines receiving assistance to report their cost-cutting plans to GAO. GAO was also required to report on the financial condition of the U.S. airline industry by Vision 100--Century of Aviation Reauthorization Act, which became law in January 2004. In consultation with the Congress, GAO agreed to satisfy these directives and report to the Congress on (1) the major challenges to the airline industry since 1998, (2) measures airlines report taking to remain financially viable, (3) the current financial and operating condition of the industry, and …
Date: August 11, 2004
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
A comparative analysis of business structures suitable forfarmer-owned wind power projects in the United States (open access)

A comparative analysis of business structures suitable forfarmer-owned wind power projects in the United States

For years, farmers in the United States have looked with envy on their European counterparts' ability to profitably farm the wind through ownership of distributed, utility-scale wind projects. Only within the past few years, however, has farmer- or community-owned wind power development become a reality in the United States. The primary hurdle to this type of development in the United States has been devising and implementing suitable business and legal structures that enable such projects to take advantage of tax-based federal incentives for wind power. This article discusses the limitations of such incentives in supporting farmer- or community-owned wind projects, describes four ownership structures that potentially overcome such limitations, and finally conducts comparative financial analysis on those four structures, using as an example a hypothetical 1.5 MW farmer-owned project located in the state of Oregon. We find that material differences in the competitiveness of each structure do exist, but that choosing the best structure for a given project will largely depend on the conditions at hand; e.g., the ability of the farmer(s) to utilize tax credits, preference for individual versus ''cooperative'' ownership, and the state and utility service territory in which the project will be located.
Date: November 11, 2004
Creator: Bolinger, Mark & Wiser, Ryan
Object Type: Report
System: The UNT Digital Library
Comparison of Electron Cloud Simulation and Experiments in the High-Current Experiment (open access)

Comparison of Electron Cloud Simulation and Experiments in the High-Current Experiment

Contaminating clouds of electrons are a common concern for accelerators of positive-charged particles, but there are some unique aspects of heavy-ion accelerators for fusion and high-energy density physics which make modeling such clouds especially challenging. In particular, self-consistent electron and ion simulation is required, including a particle advance scheme which can follow electrons in regions where electrons are strongly, weakly, and un-magnetized. We describe our approach to such self-consistency, and in particular a scheme for interpolating between full-orbit (Boris) and drift-kinetic particle pushes that enables electron time steps long compared to the typical gyro period in the magnets. We present tests and applications: simulation of electron clouds produced by three different kinds of sources indicates the sensitivity of the cloud shape to the nature of the source; first-of-a-kind self-consistent simulation of electron-cloud experiments on the High-Current Experiment (HCX) at LBNL, in which the machine can be flooded with electrons released by impact of the ion beam on an end plate, demonstrate the ability to reproduce key features of the ion-beam phase space; and simulation of a two-stream instability of thin beams in a magnetic field demonstrate the ability of the large-timestep mover to accurately calculate the instability.
Date: November 11, 2004
Creator: Cohen, R H; Friedman, A; Covo, M K; Lund, S M; Molvik, A W; Bieniosek, F M et al.
Object Type: Article
System: The UNT Digital Library

Comparison of up-scaling methods in poroelasticity and its generalizations

None
Date: June 11, 2004
Creator: Berryman, James G.
Object Type: Presentation
System: The UNT Digital Library
Compositing, Homogenization, and Characterization of Samples from Hanford Tank 241-AN-107 (open access)

Compositing, Homogenization, and Characterization of Samples from Hanford Tank 241-AN-107

As part of the program to provide pretreatment development and testing services to support the River Protection Project-Waste Treatment Plant (RPP-WTP) mission to treat Hanford tank waste, an approximately 5 L sample of waste from Tank 241-AN-107 was received at the Savannah River Technology Center (SRTC). The waste sample was characterized and mixed with recycle streams to provide feed for pretreatment testing. The characterization data provides a basis for rational development of pretreatment processes, verification of tank composition,and development of physical design parameters for the pretreatment plant.
Date: March 11, 2004
Creator: Martin, K.B.
Object Type: Report
System: The UNT Digital Library
CREME: Cis-Regulatory Module Explorer for the Human Genome (open access)

CREME: Cis-Regulatory Module Explorer for the Human Genome

The binding of transcription factors to specific regulatory sequence elements is a primary mechanism for controlling gene transcription. Eukaryotic genes are often regulated by several transcription factors, whose binding sites are tightly clustered and form cis-regulatory modules. In this paper we present a web-server, CREME, for identifying and visualizing cis-regulatory modules in the promoter regions of a given set of potentially co-regulated genes. CREME relies on a database of putative transcription factor binding sites that have been annotated across the human genome using a library of position weight matrices and evolutionary conservation with the mouse and rat genomes. A search algorithm is applied to this dataset to identify combinations of transcription factors whose binding sites tend to co-occur in close proximity in the promoter regions of the input gene set. The identified cis-regulatory modules are statistically scored and significant combinations are reported and graphically visualized. Our web-server is available at http://creme.dcode.org/.
Date: February 11, 2004
Creator: Loots, G G; Sharan, R; Ovcharenko, I & Ben-Hur, A
Object Type: Article
System: The UNT Digital Library
Cryogenic Facitlity Design in Bepc Ii Superconducting Upgrade. (open access)

Cryogenic Facitlity Design in Bepc Ii Superconducting Upgrade.

Three kinds of superconducting device are to be constructed at interaction regions in the upgrade of Beijing Electron-Positron Collider (BEPCII). Two sets of refrigerators with each capacity of 500W at 4.5K are adopted to provide the refrigeration for them. The cryogenic systems to support the operation of the superconducting facilities are under design by Harbin Institute of Technology in China. This paper presents the current design of main cryogenic facilities.
Date: May 11, 2004
Creator: Jia, L. X.; Wang, L.; Yang, G. D. & Al., Et
Object Type: Article
System: The UNT Digital Library
CRYOGENIC SYSTEM FOR BEPCII SRF CAVITY, IR QUADRUPOLE AND DETECTOR SOLENOID MAGNETS. (open access)

CRYOGENIC SYSTEM FOR BEPCII SRF CAVITY, IR QUADRUPOLE AND DETECTOR SOLENOID MAGNETS.

Beijing Electron-Positron Collider Upgrade (BEPCII) requires three types of superconducting facilities, including one pair of SRF cavities, one pair of interaction region quadrupole magnets, and one detector solenoid magnet. The cryo-plant for BEPCII has a total cooling capacity of 1kW at 4.5K, which is composed of two separate helium refrigerators of 500W each. Two refrigerators share the same gas storage and recovery system. The engineering design for the cryogenic systems, including power leads, control dewars, subcooler, cryogenic valve boxes, cryogenic transfer-lines and cryogenic controls, is completed. The production of its subsystem is under way. This paper summarizes the progress in cryogenics of the BEPCII project.
Date: May 11, 2004
Creator: JIA,J. X. & L., WANG.
Object Type: Article
System: The UNT Digital Library
Defense Space Activities: Additional Actions Needed to Implement Human Capital Strategy and Develop Space Personnel (open access)

Defense Space Activities: Additional Actions Needed to Implement Human Capital Strategy and Develop Space Personnel

A letter report issued by the Government Accountability Office with an abstract that begins "The Department of Defense (DOD) relies on space for many critical capabilities, and its continued success in space operations depends on having sufficient space-qualified personnel. Space-qualified personnel are needed to develop technology, doctrine, and concepts and operate complex systems. In the National Defense Authorization Act for Fiscal Year 2004, Congress required DOD to develop a strategy for developing and integrating national security space personnel. DOD completed it in February 2004. Congress also required GAO to assess DOD's space human capital strategy and the military services' efforts to develop their space personnel. In the first of two required reports, GAO assessed (1) whether DOD's space human capital strategy and management approach promote development and integration of the services' space personnel and (2) the extent of the services' initiatives to develop and manage their space personnel."
Date: August 11, 2004
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
Demonstration of optimization techniques for groundwater plumeremediation using iTOUGH2 (open access)

Demonstration of optimization techniques for groundwater plumeremediation using iTOUGH2

We examined the potential use of standard optimization algorithms as implemented in the inverse modeling code iTOUGH2 (Finsterle, 1999abc) for the solution of aquifer remediation problems. Costs for the removal of dissolved or free-phase contaminants depend on aquifer properties, the chosen remediation technology, and operational parameters (such as number of wells drilled and pumping rates). A cost function must be formulated that may include actual costs and hypothetical penalty costs for incomplete cleanup; the total cost function is therefore a measure of the overall effectiveness and efficiency of the proposed remediation scenario. The cost function is then minimized by automatically adjusting certain decision or operational parameters. We evaluate the impact of these operational parameters on remediation using a three-phase, three-component flow and transport simulator, which is linked to nonlinear optimization routines. We demonstrate that the methods developed for automatic model calibration are capable of minimizing arbitrary cost functions. An example of co-injection of air and steam makes evident the need for coupling optimization routines with an accurate state-of-the-art process simulator. Simplified models are likely to miss significant system behaviors such as increased downward mobilization due to recondensation of contaminants during steam flooding, which can be partly suppressed by the co-injection …
Date: November 11, 2004
Creator: Finsterle, Stefan
Object Type: Article
System: The UNT Digital Library