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A 201 MHz RF cavity design with non-stressed pre-curved Be windows for muon cooling channels (open access)

A 201 MHz RF cavity design with non-stressed pre-curved Be windows for muon cooling channels

We present a 201-MHz RF cavity design for muon cooling channels with non-stressed and pre-curved Be foils to terminate the beam apertures. The Be foils are necessary to improve the cavity shunt impedance with large beam apertures needed for accommodating large transverse size muon beams. Be is a low-Z material with good electrical and thermal properties. It presents an almost transparent window to muon beams, but terminates the RF cavity electro-magnetically. Previous designs use pre-stressed flat Be foils in order to keep cavity from detuning resulted from RF heating on the window surface. Be foils are expensive, and it is difficult to make them under desired tension. An alternative design is to use precurved and non-stressed Be foils where the buckling direction is known, and frequency shifts can be properly predicted. We will present mechanical simulations on the Be foils in this paper.
Date: May 1, 2003
Creator: Li, Derun; Ladran, A.; Staples, J.; Virostek, S.; Zisman, M.; Lau, W. et al.
Object Type: Article
System: The UNT Digital Library
An Abstract Description Approach to the Discovery and Classification of Bioinformatics Web Sources (open access)

An Abstract Description Approach to the Discovery and Classification of Bioinformatics Web Sources

The World Wide Web provides an incredible resource to genomics researchers in the form of dynamic data sources--e.g. BLAST sequence homology search interfaces. The growth rate of these sources outpaces the speed at which they can be manually classified, meaning that the available data is not being utilized to its full potential. Existing research has not addressed the problems of automatically locating, classifying, and integrating classes of bioinformatics data sources. This paper presents an overview of a system for finding classes of bioinformatics data sources and integrating them behind a unified interface. We examine an approach to classifying these sources automatically that relies on an abstract description format: the service class description. This format allows a domain expert to describe the important features of an entire class of services without tying that description to any particular Web source. We present the features of this description format in the context of BLAST sources to show how the service class description relates to Web sources that are being described. We then show how a service class description can be used to classify an arbitrary Web source to determine if that source is an instance of the described service. To validate the effectiveness …
Date: May 1, 2003
Creator: Rocco, D & Critchlow, T J
Object Type: Article
System: The UNT Digital Library
Accelerated Stress Testing of Thin-Film Modules with SnO2:F Transparent Conductors (open access)

Accelerated Stress Testing of Thin-Film Modules with SnO2:F Transparent Conductors

This paper reviews a testing program conducted at NREL for the past two years that applied voltage, water vapor, and light stresses to thin-film photovoltaic (PV) modules with SnO2:F transparent conducting oxides (TCOs) deposited on soda-lime glass superstrates. Electrochemical corrosion at the glass-TCO interface was observed to result in delamination of the thin-film layers. Experimental testing was directed toward accelerating the corrosion and understanding the nature of the resulting damage.
Date: May 1, 2003
Creator: Osterwald, C. R.; McMahon, T. J.; del Cueto, J. A.; Adelstein, J. & Puett, J.
Object Type: Article
System: The UNT Digital Library
Accelerator Magnet Plugging By Metal Oxides: A Theoretical Investigation, Remediation, and Preliminary Results (open access)

Accelerator Magnet Plugging By Metal Oxides: A Theoretical Investigation, Remediation, and Preliminary Results

The Thomas Jefferson National Accelerator Facility has experienced magnet overheating at high power. Overheating is caused by cooling water passages becoming plugged and is a direct result of the Dean Effect deposition of corrosion products suspended in the water. Salving simplified dynamic model equations of the flow in the magnet tubing bends yielded a relationship for plugging rate as a function of particle size, concentration, velocity, channel width and bend radius. Calculated deposition rates using data from a previous study are promising. Remediation has consisted of submicron filtration, magnet cleaning, and dissolved oxygen removal. Preliminary results are good: no accelerator outages have been attributed to magnet plugging since the remediation has been completed.
Date: May 1, 2003
Creator: Rust, William W.
Object Type: Article
System: The UNT Digital Library
ACME: Algorithms for Contact in a Multiphysics Environment API Version 1.3 (open access)

ACME: Algorithms for Contact in a Multiphysics Environment API Version 1.3

An effort is underway at Sandia National Laboratories to develop a library of algorithms to search for potential interactions between surfaces represented by analytic and discretized topological entities. This effort is also developing algorithms to determine forces due to these interactions for transient dynamics applications. This document describes the Application Programming Interface (API) for the ACME (Algorithms for Contact in a Multiphysics Environment) library.
Date: May 1, 2003
Creator: BROWN, KEVIN H.; VOTH, THOMAS E.; GLASS, MICHEAL W.; GULLERUD, ARNE S.; HEINSTEIN, MARTIN W. & JONES, REESE E.
Object Type: Report
System: The UNT Digital Library
Adhesion Strength Study of EVA Encapsulants on Glass Substrates (open access)

Adhesion Strength Study of EVA Encapsulants on Glass Substrates

An extensive peel-test study was conducted to investigate the various factors that may affect the adhesion strength of photovoltaic module encapsulants, primarily ethylene-vinyl acetate (EVA), on glass substrates of various laminates based on a common configuration of glass/encapsulant/backfoil. The results show that"pure" or"absolute" adhesion strength of EVA-to-glass was very difficult to obtain because of tensile deformation of the soft, semi-elastic EVA layer upon pulling. A mechanically"strong enough" backing foil on the EVA was critical to achieving the"apparent" adhesion strength. Peel test method with a 90-degree-pull yielded similar results to a 180-degree-pull. The 90-degree-pull method better revealed the four stages of delamination failure of the EVA/backfoil layers. The adhesion strength is affected by a number of factors, which include EVA type, formulation, backfoil type and manufacturing source, glass type, and surface priming treatment on the glass surface or on the backfoil. Effects of the glass-cleaning method and surface texture are not obvious. Direct priming treatments used in the work did not improve, or even worsened, the adhesion. Aging of EVA by storage over~5 years reduced notably the adhesion strength. Lower adhesion strengths were observed for the blank (unformulated) EVA and non-EVA copolymers, such as poly(ethylene-co-methacrylate) (PEMA) or poly(ethylene-co-butylacrylate) (PEBA). Their adhesion …
Date: May 1, 2003
Creator: Pern, F. J. & Glick, S. H.
Object Type: Article
System: The UNT Digital Library
Advanced CIGS Photovoltaic Technology: Annual Technical Report, 15 November 2001-14 November 2002 (open access)

Advanced CIGS Photovoltaic Technology: Annual Technical Report, 15 November 2001-14 November 2002

Energy Photovoltaics, Inc. (EPV) has consistently pursued a vacuum-based approach to CIGS production, using novel linear-source technology and standard soda-lime glass substrates. It has also chosen to develop processing methods with worker safety in mind. These choices result in layers having controllable purity and low physical defects, and production without significant hazards. Considerations such as these are important in helping to minimize the processing costs of CIGS. Technically, thin-film PV technologies have advanced considerably in the last few years. EPV successfully produced high-quality 0.43m2 Mo-coated glass substrates that, when cut, enabled NREL to produce 17.1% CIGS cells on such substrates. EPV successfully used novel linear evaporative sources for supply of Cu, In, Ga, and Se to form CIGS on 0.43m2 substrates, producing modules with Voc's of up to 37 V. A new approach to buffer-layer deposition was pioneered through synthesis of the compound ZnIn2Se4 and its use as a source material. In addition, the current generated in exploratory a-Si/a-Si/CIGS stacked devices was increased from 6 to 13 mA/cm2. Supporting these programs, EPV's upgraded analytical laboratories provided rapid in-house feedback concerning material and device properties. The objective of this subcontract is to develop and assemble the various pieces of new technology …
Date: May 1, 2003
Creator: Delahoy, A. E. & Chen, L.
Object Type: Report
System: The UNT Digital Library
Advanced Concepts for Photovoltaic Cells (open access)

Advanced Concepts for Photovoltaic Cells

Novel approaches to high efficiency photovoltaic cells are discussed that are based on the use of semiconductor quantum dots to slow hot electron cooling and thus produce either enhanced photocurrents through impact ionization or enhanced photovoltages through hot electron transport and collection.
Date: May 1, 2003
Creator: Nozik, A. J.
Object Type: Article
System: The UNT Digital Library
ADVANCED GAS TURBINE SYSTEMS RESEARCH PROGRAM (open access)

ADVANCED GAS TURBINE SYSTEMS RESEARCH PROGRAM

The quarterly activities of the Advanced Gas Turbine Systems Research (AGTSR) program are described in this quarterly report. As this program administers research, we have included all program activity herein within the past quarter as dated. More specific research progress reports are provided weekly at the request of the AGTSR COR and are being sent to NETL As for the administration of this program, items worthy of note are presented in extended bullet format following the appropriate heading. No new memberships, workshops, research projects, internships, faculty fellowships or special studies were initiated during this reporting period. Contract completion is set for June 30, 2003. During the report period, nine subcontractor reports were received (5 final reports and 4 semi-annual reports). The report technology distribution is as follows: 3--aero-heat transfer, 2--combustion and 4--materials. AGTSR continues to project that it will under spend DOE obligated funds by approximately $329K.
Date: May 1, 2003
Creator: Golan, Lawrence P.
Object Type: Report
System: The UNT Digital Library
ADVANCED GAS TURBINE SYSTEMS RESEARCH PROGRAM (open access)

ADVANCED GAS TURBINE SYSTEMS RESEARCH PROGRAM

The activities of the Advanced Gas Turbine Systems Research (AGTSR) program for the reporting period October 1, 2002 to December 31, 2002 are described in this quarterly report. No new membership, workshops, research projects, internships, faculty fellowships or special studies were initiated during this reporting period. Contract completion is set for June 30, 2003. During the report period, six research progress reports were received (3 final reports and 3 semi-annual reports). The University of Central Florida contract SR080 was terminated during this period, as UCF was unable to secure research facilities. AGTSR now projects that it will under spend DOE obligated funds by approximately 340-350K$.
Date: May 1, 2003
Creator: Golan, Lawrence P.
Object Type: Report
System: The UNT Digital Library
Advanced NDE Technologies for Powder Metal Components (open access)

Advanced NDE Technologies for Powder Metal Components

Nondestructive evaluation encompasses numerous technologies that assess materials and determine important properties. This paper demonstrates the applicability of several of these technologies to the field of powder metallurgy. The usual application of nondestructive evaluation is to detect and quantify defects in fully sintered product. But probably its most appealing role is to sense problems earlier in the manufacturing process to avoid making defects at all. Also nondestructive evaluation can be incorporated into the manufacturing processes to monitor important parameters and control the processes to produce defect free product. Nondestructive evaluation can characterize powders, evaluate components in the green state, monitor the sintering process, and inspect the final component.
Date: May 1, 2003
Creator: Martin, Peter; Haskins, Jerry; Thomas, Graham & Dolan, Ken
Object Type: Article
System: The UNT Digital Library
ADVANCED RADIATION THEORY SUPPORT ANNUAL REPORT 2002, FINAL REPORT (open access)

ADVANCED RADIATION THEORY SUPPORT ANNUAL REPORT 2002, FINAL REPORT

Z-PINCH PHYSICS RADIATION FROM WIRE ARRAYS. This report describes the theory support of DTRA's Plasma Radiation Source (PRS) program carried out by NRL's Radiation Hydrodynamics Branch (Code 6720) in FY 2002. Included is work called for in DTRA MIPR 02-2045M - ''Plasma Radiation Theory Support'' and in DOE's Interagency Agreement DE-AI03-02SF22562 - ''Spectroscopic and Plasma Theory Support for Sandia National Laboratories High Energy Density Physics Campaign''. Some of this year's work was presented at the Dense Z-Pinches 5th International Conference held June 23-28 in Albuquerque, New Mexico. A common theme of many of these presentations was a demonstration of the importance of correctly treating the radiation physics for simulating Plasma Radiation Source (PRS) load behavior and diagnosing load properties, e.g, stagnation temperatures and densities. These presentations are published in the AIP Conference Proceedings and, for reference, they are included in Section 1 of this report. Rather than describe each of these papers in the Executive Summary, they refer to the abstracts that accompany each paper. As a testament to the level of involvement and expertise that the Branch brings to DTRA as well as the general Z-Pinch community, eight first-authored presentations were contributed at this conference as well as a …
Date: May 1, 2003
Creator: Davis, J.; Apruzese, J; Chong, Y.; Clark, R.; Dasgupta, A.; Giuliani, J. et al.
Object Type: Report
System: The UNT Digital Library
The Albany News (Albany, Tex.), Vol. 127, No. 47, Ed. 1 Thursday, May 1, 2003 (open access)

The Albany News (Albany, Tex.), Vol. 127, No. 47, Ed. 1 Thursday, May 1, 2003

Weekly newspaper from Albany, Texas that includes local, county, and state news along with extensive advertising.
Date: May 1, 2003
Creator: Lucas, Melinda L.
Object Type: Newspaper
System: The Portal to Texas History
Alternative Fuel News, Vol. 7, No. 1 (open access)

Alternative Fuel News, Vol. 7, No. 1

Quarterly magazine with articles on alternative fueling station best practices, alt fuel shool buses, AFVs at L.L. Bean, Clean Cites and the Hydrogen Future, by DOE Assistant Secretary David Garman.
Date: May 1, 2003
Creator: unknown
Object Type: Journal/Magazine/Newsletter
System: The UNT Digital Library
Amorphous and Thin-Film Silicon (open access)

Amorphous and Thin-Film Silicon

This paper outlines the key concepts set forth in the Amorphous and Thin-Film Silicon session at the National Center for Photovoltaics and Solar Program Review Meeting held March 26, 2003 in Denver, Colorado. Key elements of discussion centered around benchmarking the NREL/NCPV amorphous and thin-film silicon program, identifying holes in the scientific understanding of these materials and devices, identifying hurdles to large scale manufacturing, and what direction the program should take for future activities.
Date: May 1, 2003
Creator: Nelson, B. P.; Atwater, H. A.; von Roedern, B.; Yang, J.; Sims, P.; Deng, X. et al.
Object Type: Article
System: The UNT Digital Library
Analysis of a grid window structure for RF cavities in a Muon cooling channel (open access)

Analysis of a grid window structure for RF cavities in a Muon cooling channel

We report on the electromagnetic and thermal analysis of a grid window structure for high gradient, low frequency RF cavities. Windows may be utilized to close the beam iris and increase shunt impedance of closed-cell RF cavities. This work complements previous work presented for windows made of solid beryllium foil. An electromagnetic and thermal analysis of the thin wall tubes in a grid pattern was conducted using both MAFIA4 and ANSYS finite element analyses. The results from both codes agreed well for a variety of grid configurations and spacing. The grid configuration where the crossing tubes touched was found to have acceptable E-Fields and H-Fields performance. The thermal profiles for the grid will also be shown to determine a viable cooling profile.
Date: May 1, 2003
Creator: Ladran, A.; Li, D.; Moretti, A.; Rimmer, R.; Staples, J.; Virostek, S. et al.
Object Type: Article
System: The UNT Digital Library
Analysis of the Massive Salt Fall in Big Hill Cavern 103 (open access)

Analysis of the Massive Salt Fall in Big Hill Cavern 103

This report summarizes recent reviews, observations, and analyses believed to be imperative to our understanding of the recent two million cubic feet salt fall event in Big Hill Cavern 103, one of the caverns of the Strategic Petroleum Reserve (SPR). The fall was the result of one or more stress driven mechanical instabilities, the origins of which are discussed in the report. The work has lead to important conclusions concerning the engineering and operations of the caverns at Big Hill. Specifically, Big Hill, being the youngest SPR site, was subjected to state-of-the-art solutioning methods to develop nominally well-formed, right-circular cylindrical caverns. Examination of the pressure history records indicate that operationally all Big Hill SPR caverns have been treated similarly. Significantly, new three-dimensional (3-D) imaging methods, applied to old (original) and more recent sonar survey data, have provided much more detailed views of cavern walls, roofs, and floors. This has made possible documentation of the presence of localized deviations from ''smooth'' cylindrical cavern walls. These deviations are now recognized as isolated, linear and/or planar features in the original sonar data (circa early 1990s), which persist to the present time. These elements represent either sites of preferential leaching, localized spalling, or a …
Date: May 1, 2003
Creator: MUNSON, DARRELL E.; BAUER, STEPHEN J.; RAUTMAN, CHRISTOPHER A.; EHGARTNER, BRIAN L. & SATTLER, ALLAN R.
Object Type: Report
System: The UNT Digital Library
Annual report procurement and logistics management center Sandia National Laboratories fiscal year 2002. (open access)

Annual report procurement and logistics management center Sandia National Laboratories fiscal year 2002.

This report summarizes the purchasing and transportation activities of the Procurement and Logistics Management Center for Fiscal Year 2002. Activities for both the New Mexico and California locations are included.
Date: May 1, 2003
Creator: Palmer, David L.
Object Type: Report
System: The UNT Digital Library
Application of High-Temperature Mold Materials to Die Cast Copper Motor Rotor for Improved Efficiency (open access)

Application of High-Temperature Mold Materials to Die Cast Copper Motor Rotor for Improved Efficiency

The objective of the study, Application of High-Temperature Mold Materials to Die Cast Copper Motor Rotor for Improved Efficiency, was to support the Copper Development Association (CDA) in its effort to design, fabricate and demonstrate mold technologies designed to withstand the copper motor rotor die casting environment for an economically acceptable life. The anticipated result from the compiled data and tests were to: (1) identify materials suitable for die casting copper, (2) fabricate motor rotor molds and (3) supply copper rotor motors for testing in actual compressor systems. Compressor manufacturers can apply the results to assess the technical and economical viability of copper rotor motors.
Date: May 1, 2003
Creator: Cowie, John G.; Edwin F. Brush, Jr.; Peters, Dale T.; Midson, Stephen P. & Son, Darryl J. Van
Object Type: Report
System: The UNT Digital Library
Archer County News (Archer City, Tex.), No. 18, Ed. 1 Thursday, May 1, 2003 (open access)

Archer County News (Archer City, Tex.), No. 18, Ed. 1 Thursday, May 1, 2003

Weekly newspaper from Archer City, Texas that includes local, state, and national news along with advertising.
Date: May 1, 2003
Creator: Lewis, Shelley
Object Type: Newspaper
System: The Portal to Texas History
Assess Current and Potential Salmonid Production in Rattlesnake Creek Associated with Restoration Efforts; Yakama Indian Nation, Annual Report 2002-2003. (open access)

Assess Current and Potential Salmonid Production in Rattlesnake Creek Associated with Restoration Efforts; Yakama Indian Nation, Annual Report 2002-2003.

This document represents the FY2002 BPA contract Statement of Work for the Yakama Nation (YN) portion of the project entitled 'Assessment of current and potential salmonid production in Rattlesnake Creek associated with restoration efforts'. The purpose of the project is to complete detailed surveys of water quality, fish populations, habitat conditions and riparian health in the Rattlesnake Creek sub-basin of the White Salmon River in south central Washington. Results of the surveys will be used to establish Rattlesnake Creek sub-basin baseline environmental factors prior to anticipated removal of Condit Dam in 2006 and enable cost-effective formulation of future watershed restoration strategies.
Date: May 1, 2003
Creator: Morris, Gregory
Object Type: Report
System: The UNT Digital Library
Assessing Wind Integration Costs with Dispatch Models: A Case Study of PacifiCorp; Preprint (open access)

Assessing Wind Integration Costs with Dispatch Models: A Case Study of PacifiCorp; Preprint

Conventional electric production simulation models do not fully capture the unique issues surrounding wind power plants. PacifiCorp used an hourly system dispatch model to estimate wind resource integration costs in its Integrated Resource Plan (IRP). This paper explores a number of modeling issues surrounding the representation of wind integration costs in dispatch models and the implications for calculating wind integration costs. Such issues include unit commitment logic, reserve requirement calculations, and wind forecast accuracy. We also discuss methods of assessing integration costs outside the conventional modeling framework, and we present some wind-related results from the PacifiCorp IRP. We believe that this paper will be of value for utilities and control areas that are involved in assessing potential wind impacts and integration cost and will help provide a framework for future model development. These modeling issues need to be addressed by the modeling community as wind becomes a significant part of utility resource portfolios.
Date: May 1, 2003
Creator: Dragoon, K. & Milligan, M.
Object Type: Article
System: The UNT Digital Library
Atomic Structure of Twin Boundaries in CdTe (open access)

Atomic Structure of Twin Boundaries in CdTe

Using the combination of high-resolution transmission electron microscopy, first-principles density-functional total energy calculations, and image simulations, we determined the atomic structure of lamellar twin and double-positioning twin boundaries in CdTe. We find that the structure of lamellar twin boundaries has no dangling bonds or wrong bonds; thus, it results in negligible effects on the electronic properties. The structure of double-positioning twin boundaries, however, contain both Cd and Te dangling bonds, and therefore produce energy states in the bandgap that are detrimental to the electronic properties of CdTe.
Date: May 1, 2003
Creator: Yan, Y.; Jones, K. M. & Al-Jassim, M. M.
Object Type: Article
System: The UNT Digital Library
Audit Guide: Auditing and Investigating the Internal Control of Government Purchase Card Programs (Superseded by GAO-04-87G) (open access)

Audit Guide: Auditing and Investigating the Internal Control of Government Purchase Card Programs (Superseded by GAO-04-87G)

Guidance issued by the General Accounting Office with an abstract that begins "This publication has been superseded by GAO-04-87G, Audit Guide: Auditing and Investigating the Internal Control of Government Purchase Card Programs, November 2003. The federal government of the United States--the largest and most complex organization in the world--expended approximately $15 billion through federal organizations' purchase card programs in fiscal year 2002. As the steward of taxpayer dollars, federal agencies are accountable for how purchase cards are used and how the funds are spent. To that end, federal agencies are responsible for establishing and maintaining internal control to provide reasonable assurance that (1) the goals and objectives of the purchase card program are met and (2) safeguards against fraudulent, improper, and abusive purchases are adequate. Recent congressional testimony and Inspector General and GAO reports show that some federal agencies do not have adequate internal control over their purchase card programs. Without effective internal control, management has little assurance that fraudulent, improper, and abusive purchases are being prevented or, if occurring, are being promptly detected with appropriate corrective actions taken. A key element of internal control is monitoring that assesses the quality of performance over time and ensures that the findings …
Date: May 1, 2003
Creator: United States. General Accounting Office.
Object Type: Text
System: The UNT Digital Library