805 MHz and 201 MHz RF cavity development for MUCOOL (open access)

805 MHz and 201 MHz RF cavity development for MUCOOL

A muon cooling channel calls for very high acceleratinggradient RF structures to restore the energy lost by muons in theabsorbers. The RF structures have to be operated in a strong magneticfield and thus the use of superconducting RF cavities is excluded. Toachieve a high shunt impedance while maintaining a large enough apertureto accommodate a large transverse emittance muon beam, the cavity designadopted is a pillbox-like geometry with thin Be foils to terminate theelectromagnetic field at the cavity iris. The possibility of using gridsof thin-walled metallic tubes for the termination is also being explored.Many of the RF-related issues for muon cooling channels are being studiedboth theoretically and experimentally using an 805 MHz cavity that has apillbox-like geometry with thin Be windows to terminate the cavityaperture. The design and performance of this cavity are reported here.High-power RF tests of the 805 MHz cavity are in progress at Lab G inFermilab. The cavity has exceeded its design gradient of 30 MV/m,reaching 34 MV/m without external magnetic field. No surface damage wasobserved at this gradient. The cavity is currently under conditioning atLab G with an external magnetic field of 2.5 T. We also present here a201 MHz cavity design for muoncooling channels. The proposed …
Date: October 10, 2002
Creator: DLi@lbl.gov
Object Type: Article
System: The UNT Digital Library
AISI/DOE Technology Roadmap Program: Improved Surface Quality of Exposed Automotive Sheet Steels (open access)

AISI/DOE Technology Roadmap Program: Improved Surface Quality of Exposed Automotive Sheet Steels

Surface quality of sheet steels is an important economic and technical issue for applications such as critical automotive surfaces. This project was therefore initiated to develop a more quantitative methodology for measuring surface imperfections, and to assess their response to forming and painting, particularly with respect to their visibility or invisibility after painting. The objectives were met, and included evaluation of a variety of imperfections present on commercial sheet surfaces or simulated using methods developed in the laboratory. The results are expected to have significant implications with respect to the methodology for assessing surface imperfections, development of quantitative criteria for surface inspection, and understanding and improving key painting process characteristics that influence the perceived quality of sheet steel surfaces.
Date: October 10, 2002
Creator: Speer, John G.; Matlock, David K.; Meyers, Noel & Choi, Young-Min
Object Type: Report
System: The UNT Digital Library
Constant Load SCC Initiation Response of Alloy 22 (UNS N06022), Titanium Grade 7 and Stainless Steels at 105C (open access)

Constant Load SCC Initiation Response of Alloy 22 (UNS N06022), Titanium Grade 7 and Stainless Steels at 105C

This paper provides an update on research addressing the effects of material condition and applied stress on stress corrosion cracking (SCC) in waste package and drip shield materials for the Yucca Mountain Project. Time-to-failure experiments are being performed on smooth bar tensile specimens in a hot, concentrated, mixed-salt solution chosen to simulate concentrated Yucca Mountain water. The effects of applied stress, welding, surface finish, shot peening, cold work, crevicing, and aging treatment are being investigated for Alloy 22 (UNS N06022). Aging treatments were designed to produce topologically close-packed phases (TCP) and long-range ordering (LRO) and are under investigation as worse-case scenarios for possible microstructures in Alloy 22 (UNS N06022). Titanium Grade 7 and 3 16NG stainless steel are included in the matrix, as they are identified for drip shield and waste package components, respectively. Sensitized 304SS specimens are included in the test matrix to provide benchmark data. This research complements high-resolution crack-growth-rate experiments currently being performed in a parallel research project.
Date: October 10, 2002
Creator: Young, L. M.; Catlin, G. M.; Andresen, P. L. & Gordon, G. M.
Object Type: Report
System: The UNT Digital Library
Development of the low return loss 340-size ceramic window for the APS linac. (open access)

Development of the low return loss 340-size ceramic window for the APS linac.

The Advanced Photon Source (APS) linac high-power switching system makes use of 340-size waveguide components. These components include vacuum-grade furnace-brazed transitions, pressurized-grade aluminum 340-size switches, and more recently 340-size ceramic windows. The fabrication of these 340-size windows proceeded with brazing of ceramic membrane to thin-walled copper sleeves and real-time network analyzer testing performed by the ASD (Accelerator Systems Division) RF (Radio Frequency) Group. Initially it was thought that this real-time testing of prototype hardware would be necessary in the investigative stage to establish the required dimensions and physical geometry to satisfy the 40-dB return-loss criteria. However, producing four windows now installed involved real-time network analyzer testing during production of each window conducted in parallel with adjustments of tuners designed into each 340-size ceramic window.
Date: October 10, 2002
Creator: Berg, S.; Bromberek, D.; Goeppner, G.; Haase, A.; Hoyt, J.; Michalek, W. et al.
Object Type: Article
System: The UNT Digital Library
The Effect of pH on Nickel Alloy SCC and Corrosion Performance (open access)

The Effect of pH on Nickel Alloy SCC and Corrosion Performance

Alloy X-750 condition HTH stress corrosion crack growth rate (SCCGR) tests have been conducted at 360 C (680 F) with 50 cc/kg hydrogen as a function of coolant pH. Results indicate no appreciable influence of pH on crack growth in the pH (at 360 C) range of {approx} 6.2 to 8.7, consistent with previous alloy 600 findings. These intermediate pH results suggest that pH is not a key variable which must be accounted for when modeling pressurized water reactor (PWR) primary water SCC. In this study, however, a nearly three fold reduction in X-750 crack growth rate was observed in reduced pH environments (pH 3.8 through HCl addition and pH 4-5.3 through H{sub 2}SO{sub 4} addition). Crack growth rates did not directly correlate with corrosion film thickness. In fact, 10x thicker corrosion films were observed in the reduced pH environments.
Date: October 10, 2002
Creator: Morton, D.S. & Hansen, M.
Object Type: Report
System: The UNT Digital Library
Elections Reform: Overview and Issues (open access)

Elections Reform: Overview and Issues

This report discusses several issues as the Congress considers legislation to reform the voting process, a number of issues have emerged as part of the debate: the reliability of different types of voting technologies; voting problems and irregularities in the 2000 election; problems for militaryand overseas voters; the electoral college; and early media projections of election results.
Date: October 10, 2002
Creator: Coleman, Kevin J. & Fischer, Eric A.
Object Type: Report
System: The UNT Digital Library
Environmental regulatory drivers for coal bed methane research and development. (open access)

Environmental regulatory drivers for coal bed methane research and development.

In 1999, the National Petroleum Council (NPC) stated that the resource base for meeting growing natural gas demands in the United States is adequate. A significant and increasing portion of natural gas production (8% by 2015) is expected to come from coal bed methane (CBM). The NPC cautions that for this to occur, certain factors, including compliance with environmental requirements, must be addressed. Numerous federal, state, and local programs address a variety of environmental issues, including water quality and quantity, air quality, wildlife, noise, and visibility. This paper examines existing and potential environmental regulatory requirements that could affect the timely development and production of CBM resources in the United States. Such an examination can help technology developers and policy makers target areas for research and development (R&D), demonstration, and implementation to help facilitate cost-effective CBM development and production to meet the nation's natural gas demands. It can also help identify R&D areas that will give rule-making bodies the information they need to incorporate more science into the regulatory development process.
Date: October 10, 2002
Creator: Elcock, D.; Gasper, J. & Moses, D. O.
Object Type: Article
System: The UNT Digital Library
Estimating equivalent dipole polarizabilities for the inductiveresponse of isolated conductive bodies (open access)

Estimating equivalent dipole polarizabilities for the inductiveresponse of isolated conductive bodies

Equivalent dipole polarizability matrices and equivalent dipole location are a convenient way to interpret magnetic field data due to currents induced in isolated conductive objects. The uncertainties in polarizability estimates and in equivalent dipole location provide a quantitative measure of the performance of different configurations of transmitters and receivers. These uncertainties are estimated using a linearized inversion (Smith and Morrison, 2002). For many systems, consisting of one or more rectangular loop transmitters and a number of dipole receivers, sited on a horizontal grid, equivalent dipole depth is determined to 10% accuracy to depths approximately 20% deeper, than the depths at which polarizability matrix elements can be determined to the same precision. Systems that have a lower product of rms polarizability uncertainty and square root of their number of transmitter-receiver pairs are considered more effective for the number of transmitter-receiver pairs. Among the systems studied, a system with three orthogonal transmitter loops and a three component receiver is the most effective, for objects shallower than 0.6 times the instrument siting grid spacing, yielding an rms polarizability uncertainty 0.04 times that of a single transmitter single receiver system. At intermediate depths, a system with two vertical component receivers on the diagonal of …
Date: October 10, 2002
Creator: Smith, J. Torquil & Morrison, H. Frank
Object Type: Article
System: The UNT Digital Library
Final Report - Ferrographic Tracking of Bacterial Transport (open access)

Final Report - Ferrographic Tracking of Bacterial Transport

The work performed during the past three years has been extremely productive. Ferrographic capture was utilized in analysis of several thousand field samples collected from arrays of multilevel samplers during three intensive field campaigns conducted at two shallow sandy aquifer sites in Oyster, VA. This work has shown resulted in three important conclusions: (1) Ferrographic capture provides unparalleled low quantitation limits for bacterial cell enumeration (Johnson et al., 2000). (2) The high-resolution analyses provided by ferrographic capture allowed observation of increased bacterial removal rates (from groundwater) that corresponded to increased populations of protozoa in the groundwater (Zhang et al., 2001). This novel data allowed determination of bacterial predation rates by protists in the field, a consideration that will be important for successful bioaugmentation strategies. (3) The high-resolution analyses provided by ferrographic capture allowed observation of detachment of indigenous cells in response to breakthrough of injected cells in groundwater (Johnson et al., 2001). The implication of this unique observation is that bacterial transport, specifically bacterial attachment and detachment, may be much more dynamic than has been indicated by short-term laboratory and field studies. Dynamic attachment and detachment of bacteria in groundwater may lead to greatly increased transport distances over long terms …
Date: October 10, 2002
Creator: Johnson, William P.
Object Type: Report
System: The UNT Digital Library
Global Climate Change (open access)

Global Climate Change

This report briefly reviews the status of climate science, international negotiations, and congressional activity focused specifically on climate change.
Date: October 10, 2002
Creator: Justus, John R. & Fletcher, Susan R.
Object Type: Report
System: The UNT Digital Library
Groundwater Monitoring Plan for the 216-S-10 Pond and Ditch (open access)

Groundwater Monitoring Plan for the 216-S-10 Pond and Ditch

This report describes a groundwater monitoring plan for the 216-S-10 pond and ditch on the Hanford Site. This plan complies with the requirements of RCRA, CERCLA, and 40 CFR 265. This plan provides DOE with a revised detection monitoring well network and updates the list of constituents based on the knowledge gained from data collected over the years.
Date: October 10, 2002
Creator: Williams, Bruce A. & Chou, Charissa J.
Object Type: Report
System: The UNT Digital Library
Homeland Security: Department of Justice's Response to Its Congressional Mandate to Assess and Report on Chemical Industry Vulnerabilities (open access)

Homeland Security: Department of Justice's Response to Its Congressional Mandate to Assess and Report on Chemical Industry Vulnerabilities

Correspondence issued by the General Accounting Office with an abstract that begins "Congress passed the Chemical Safety Information, Site Security and Fuels Regulatory Relief Act after a number of testimonies expressing concerns about the vulnerability of chemical facilities to criminal and terrorist attacks. According to the Attorney General's interim report, chemical facilities visited generally had safety and emergency response measures that could mitigate the consequences of a terrorist attack. The report further stated that the level of security at chemical facilities is roughly equivalent to standard security practices found in most industries. The interim report also contains nine preliminary findings that cumulatively address the other required reporting elements--the vulnerability of facilities to criminal and terrorist activity, current industry site security practices, and the security of chemicals being transported. These findings address the extent to which 11 facilities conducted facility security assessments, had the capability to respond to armed attacks, conducted emergency response exercises, conducted routine pre-employment background investigations, had secure process control systems, had secure chemical transportation containers, had adequate security measures over transportation of hazardous chemicals, received meaningful threat information, and had effective facility security systems."
Date: October 10, 2002
Creator: United States. General Accounting Office.
Object Type: Text
System: The UNT Digital Library
Improved temperature regulation of process water systems for the APS storage ring. (open access)

Improved temperature regulation of process water systems for the APS storage ring.

Beam stability and operational reliability of critical mechanical systems are key performance issues for synchrotron accelerators such as the Advanced Photon Source (APS). Stability is influenced by temperature fluctuations of the process water (PW) used for cooling and/or temperature conditioning storage ring (SR) components such as vacuum chambers, magnets, absorbers, etc. Operational reliability is crucial in maintaining facility beam operations and remaining within downtime ''budgets.'' Water systems for the APS storage ring were originally provided with a distributive control system (DCS) capable of regulation to {+-}1.0 F, as specified by facility design requirements. After several years of operation, a particular mode of component mortality indicated a need for upgrade of the temperature control system. The upgrade that was implemented was chosen for both improved component reliability and temperature stability (now on the order of {+-}0.2 F for copper components and {+-}0.05 F for aluminum components). The design employs a network of programmable logic controllers (PLCs) for temperature control that functions under supervision of the existing DCS. The human-machine interface (HMI) of the PLC system employs RSView32 software. The PLC system also interfaces with the EPICS accelerator control system to provide monitoring of temperature control parameters. Eventual supervision of the PLC …
Date: October 10, 2002
Creator: Putnam, C. & Dortwegt, R.
Object Type: Article
System: The UNT Digital Library
Iraq: Weapons Threat, Compliance, Sanctions, and U.S. Policy (open access)

Iraq: Weapons Threat, Compliance, Sanctions, and U.S. Policy

None
Date: October 10, 2002
Creator: Katzman, Kenneth
Object Type: Report
System: The UNT Digital Library
Mitigation of copper corrosion and agglomeration in APS process water systems. (open access)

Mitigation of copper corrosion and agglomeration in APS process water systems.

Copper corrosion has been observed in process water (PW) systems at the Advanced Photon Source (APS) dating to the early postcommissioning phase of the project. In time, copper corrosion products agglomerated significantly in certain preferred locations. Significant agglomerations (or deposits) can occur in copper cooling passages such as magnet conductors and x-ray absorbers having relatively large length-to-diameter ratios and where heat is removed by water cooling. Such agglomerations also occur at restrictions found in noncopper system components such as valve seats, fixed orifices, pump seal faces, etc. Modifications to the APS process water system that significantly reduce the rate of copper corrosion are discussed. These modifications have not prevented corrosion altogether. Other means used to prevent component clogging and malfunction as a result of current copper corrosion rates are listed.
Date: October 10, 2002
Creator: Dortwegt, R.; Putnam, C. & Swetin, E.
Object Type: Article
System: The UNT Digital Library
Quantum cosmology based on discrete Feynman paths (open access)

Quantum cosmology based on discrete Feynman paths

Although the rules for interpreting local quantum theory imply discretization of process, Lorentz covariance is usually regarded as precluding time quantization. Nevertheless a time-discretized quantum representation of redshifting spatially-homogeneous universe may be based on discrete-step Feynman paths carrying causal Lorentz-invariant action--paths that not only propagate the wave function but provide a phenomenologically-promising elementary-particle Hilbert-space basis. In a model under development, local path steps are at Planck scale while, at a much larger ''wave-function scale'', global steps separate successive wave-functions. Wave-function spacetime is but a tiny fraction of path spacetime. Electromagnetic and gravitational actions are ''at a distance'' in Wheeler-Feynman sense while strong (color) and weak (isospin) actions, as well as action of particle motion, are ''local'' in a sense paralleling the action of local field theory. ''Nonmaterial'' path segments and ''trivial events'' collaborate to define energy and gravity. Photons coupled to conserved electric charge enjoy privileged model status among elementary fermions and vector bosons. Although real path parameters provide no immediate meaning for ''measurement'', the phase of the complex wave function allows significance for ''information'' accumulated through ''gentle'' electromagnetic events involving charged matter and ''soft'' photons. Through its soft-photon content the wave function is an ''information reservoir''.
Date: October 10, 2002
Creator: Chew, Geoffrey F.
Object Type: Article
System: The UNT Digital Library
Recombination Parameters for Antimonide-Based Semiconductors using RF Photoreflection Techniques (open access)

Recombination Parameters for Antimonide-Based Semiconductors using RF Photoreflection Techniques

RF photoreflection measurements and PC-1D simulations have been used to evaluate bulk and surface recombination parameters in antimonide-based materials. PC-1D is used to simulate the photoconductivity response of antimonide-based substrates and doubly-capped epitaxial layers and also to determine how to extract the recombination parameters using experimental results. Excellent agreement has been obtained with a first-order model and test structure simulation when Shockley-Reed-Hall (SRH) recombination is the bulk recombination process. When radiative, Auger and surface recombination are included, the simulation results show good agreement with the model. RF photoreflection measurements and simulations using PC-1D are compatible with a radiative recombination coefficient (B) of approximately 5 x 10{sup -11} cm{sup 3}/s, Auger coefficient (C) {approx} 1.0 x 10{sup -28} cm{sup 6}/s and surface recombination velocity (SRV) {approx} 600 cm/s for 0.50-0.55 eV doubly-capped InGaAsSb material with GaSb capping layers using the experimentally determined active layer doping of 2 x 10{sup 17} cm{sup -3}. Photon recycling, neglected in the analysis and simulations presented, will affect the extracted recombination parameters to some extent.
Date: October 10, 2002
Creator: Kumar, R. J.; Borrego, J. M.; Dutta, P. S.; Gutmann, R. J.; Wang, C. A.; Martinelli, R. U. et al.
Object Type: Report
System: The UNT Digital Library
Scientific kernels on VIRAM and imagine media processors (open access)

Scientific kernels on VIRAM and imagine media processors

Many high performance applications run well below the peak arithmetic performance of the underlying machine, with inefficiencies often attributed to a lack of memory bandwidth. In this work we examine two emerging media processors designed to address the well-known gap between processor and memory performance, in the context of scientific computing. The VIRAM architecture uses novel PIM technology to combine embedded DRAM with a vector co-processor for exploiting its large bandwidth potential. The Imagine architecture, on the other hand, provides a stream-aware memory hierarchy to support the tremendous processing potential of the SIMD controlled VLIW clusters. First we develop a scalable synthetic probe that allows us to parametize key performance attributes of VIRAM and Imagine while capturing the performance crossover point of these architectures. Next we present results for two important scientific kernels each with a unique set of computational characteristics and memory access patterns. Our experiments isolate the set of application characteristics best suited for each architecture and show a promising direction towards interfacing leading-edge media processor technology with high-end scientific computations.
Date: October 10, 2002
Creator: Narayanan, Manikamdan; Oliker, Leonid; Janin, Adam; Husbands,Parry & Li, Xiaoye S.
Object Type: Report
System: The UNT Digital Library
Summary of Parallel Session I: Grid testbeds and applications (open access)

Summary of Parallel Session I: Grid testbeds and applications

This paper is a summary of talks presented at ACAT 2002 in parallel session I on grid testbeds and applications. There were 12 presentations on this topic that show a lot of enthusiasm and hard work by many people in bringing physics applications onto the grid. There are encouraging success stories and also a clear view that the middleware has a way to go until it is as robust, reliable and complete as we would like it to be.
Date: October 10, 2002
Creator: Olson, Douglas L.
Object Type: Article
System: The UNT Digital Library