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135,836 Matching Results
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The NetLogger Methodology for High Performance Distributed Systems Performance Analysis
The authors describe a methodology that enables the real-time diagnosis of performance problems in complex high-performance distributed systems. The methodology includes tools for generating precision event logs that can be used to provide detailed end-to-end application and system level monitoring; a Java agent-based system for managing the large amount of logging data; and tools for visualizing the log data and real-time state of the distributed system. The authors developed these tools for analyzing a high-performance distributed system centered around the transfer of large amounts of data at high speeds from a distributed storage server to a remote visualization client. However, this methodology should be generally applicable to any distributed system. This methodology, called NetLogger, has proven invaluable for diagnosing problems in networks and in distributed systems code. This approach is novel in that it combines network, host, and application-level monitoring, providing a complete view of the entire system.
Date:
December 23, 1999
Creator:
Tierney, Brian; Johnston, William; Crowley, Brian; Hoo, Gary; Brooks, Chris & Gunter, Dan
Object Type:
Report
System:
The UNT Digital Library
A Network-Aware Distributed Storage Cache for Data Intensive Environments
Modern scientific computing involves organizing, moving, visualizing, and analyzing massive amounts of data at multiple sites around the world. The technologies, the middleware services, and the architectures that are used to build useful high-speed, wide area distributed systems, constitute the field of data intensive computing. In this paper the authors describe an architecture for data intensive applications where they use a high-speed distributed data cache as a common element for all of the sources and sinks of data. This cache-based approach provides standard interfaces to a large, application-oriented, distributed, on-line, transient storage system. They describe their implementation of this cache, how they have made it network aware, and how they do dynamic load balancing based on the current network conditions. They also show large increases in application throughput by access to knowledge of the network conditions.
Date:
December 23, 1999
Creator:
Tierney, B. L.; Lee, J. R.; Johnston, W. E.; Crowley, B. & Holding, M.
Object Type:
Report
System:
The UNT Digital Library
Phase stability domains of (Bi,Pb-2223): Data sources, correlation, and assessment
An assessment of the phase stability of lead-doped Bi-2223, (Bi,Pb)-2223, as a function of temperature and partial pressure of oxygen, p(0{sub 2}), derived from equilibration and electromotive force studies carried out by numerous groups of investigators is presented. The data obtained from this assessment, coupled with additional more recent data from the laboratory, can be used to estimate the stability of this promising high-{Tc} bismuth cuprate system in the temperature range from 650 to 870 C and for oxygen partial pressures ranging from 10{sup {minus}5} to one atm.
Date:
December 23, 1999
Creator:
Tetenbaum, M.; Maroni, V. A.; Murphy, N. M. & Dorris, S. E.
Object Type:
Article
System:
The UNT Digital Library
Role of starting material composition in interfacial damage morphology of Hafnia Silica multilayer coatings
None
Date:
December 23, 1999
Creator:
Bevis, R P; Stolz, C J; Von Gunten, M K; Weakley, S C & Wu, Z L
Object Type:
Article
System:
The UNT Digital Library
Scenario analysis of hybrid class 3-7 heavy vehicles.
The effects of hybridization on heavy-duty vehicles are not well understood. Heavy vehicles represent a broader range of applications than light-duty vehicles, resulting in a wide variety of chassis and engine combinations, as well as diverse driving conditions. Thus, the strategies, incremental costs, and energy/emission benefits associated with hybridizing heavy vehicles could differ significantly from those for passenger cars. Using a modal energy and emissions model, they quantify the potential energy savings of hybridizing commercial Class 3-7 heavy vehicles, analyze hybrid configuration scenarios, and estimate the associated investment cost and payback time. From the analysis, they conclude that (1) hybridization can significantly reduce energy consumption of Class 3-7 heavy vehicles under urban driving conditions; (2) the grid-independent, conventional vehicle (CV)-like hybrid is more cost-effective than the grid-dependent, electric vehicle (EV)-like hybrid, and the parallel configuration is more cost-effective than the series configuration; (3) for CV-like hybridization, the on-board engine can be significantly downsized, with a gasoline or diesel engine used for SUVs perhaps being a good candidate for an on-board engine; (4) over the long term, the incremental cost of a CV-like, parallel-configured Class 3-4 hybrid heavy vehicle is about %5,800 in the year 2005 and $3,000 in 2020, while …
Date:
December 23, 1999
Creator:
An, F.; Stodolsky, F.; Vyas, A.; Cuenca, R. & Eberhardt, J. J.
Object Type:
Article
System:
The UNT Digital Library
Through the looking glass: Unraveling the network structure of coal
Since the original idea by Sanada and Honda of treating coal as a three-dimensional cross-linked network, coal structure has been probed by monitoring ingress of solvents using traditional volumetric or gravimetric methods. However, using these techniques has allowed only an indirect observation of the swelling process. More recently, the authors have developed magnetic resonance microscopy (MRM) approaches for studying solvent ingress in polymeric systems, about which fundamental aspects of the swelling process can be deduced directly and quantitatively. The aim of their work is to utilize solvent transport and network response parameters obtained from these methods to assess fundamental properties of the system under investigation. Polymer and coal samples have been studied to date. Numerous swelling parameters measured by magnetic resonance microscopy are found to correlate with cross-link density of the polymer network under investigation. Use of these parameters to assess the three-dimensional network structure of coal is discussed.
Date:
December 23, 1999
Creator:
Gregory, D. M.; Stec, D. F. & Botto, R. E.
Object Type:
Article
System:
The UNT Digital Library
Analysis of Parameters Affecting Beam Gauge Performance
Beam gauges have been used in the last decade or so for measuring the internal azimuthal compressive coil stresses in superconducting magnets. In early model Large Hadron Collider Interaction Region (LHC IR) quadrupoles tested at Fermilab, the beam gauges indicated excessively high amounts of inner and outer coil prestress during the collaring process, inconsistent with the coil size and modulus data. In response to these measurements, a simple mechanics based quantitative understanding of different factors affecting beam gauges has been developed. A finite element model with contact elements and non-linear material behavior, confirmed with experimental results, was developed. The results indicate that a small plastic deformation of either the beam or the backing plate can cause significant errors in the measured stress values. The effect of variations in coil modulus and support boundary conditions on beam gauge performance are also discussed.
Date:
December 22, 1999
Creator:
S. Yadav, J. Kerby and J.P. Ozelis
Object Type:
Article
System:
The UNT Digital Library
Argonne National Laboratory Institutional Plan FY 2000 - FY 2005.
None
Date:
December 22, 1999
Creator:
Beggs, S. D. & Director, Office of The
Object Type:
Report
System:
The UNT Digital Library
(Ba,Sr)TiO{sub 3} dielectrics: Relationship between bulk and thin film properties
Thin films of complex perovskites have a number of potentially important applications. Of major scientific and practical concern is the scaling of properties as film dimensions are reduced. This paper describes a satisfactory relationship between bulk and thin film dielectric properties of (Ba,Sr)TiO{sub 3}. Relative contributions of strain, A:B cation stoichiometry, and interface are separated to explain temperature dependent dielectric behavior.
Date:
December 22, 1999
Creator:
Kingon, A. I.; Streiffer, S. K.; Parker, C. B. & Stemmer, S.
Object Type:
Article
System:
The UNT Digital Library
Correlating radiation exposure with embrittlement: Comparative studies of electron- and neutron-irradiated pressure vessel alloys
Comparative experiments using high energy (10 MeV) electrons and test reactor neutrons have been undertaken to understand the role that primary damage state has on hardening (embrittlement) induced by irradiation at 300 C. Electrons produce displacement damage primarily by low energy atomic recoils, while fast neutrons produce displacements from considerably higher energy recoils. Comparison of changes resulting from neutron irradiation, in which nascent point defect clusters can form in dense cascades, with electron irradiation, where cascade formation is minimized, can provide insight into the role that the in-cascade point defect clusters have on the mechanisms of embrittlement. Tensile property changes induced by 10 MeV electrons or test reactor neutron irradiations of unalloyed iron and an Fe-O.9 wt.% Cu-1.0 wt.% Mn alloy were examined in the damage range of 9.0 x 10{sup {minus}5} dpa to 1.5 x 10{sup {minus}2} dpa. The results show the ternary alloy experienced substantially greater embrittlement in both the electron and neutron irradiate samples relative to unalloyed iron. Despite their disparate nature of defect production similar embrittlement trends with increasing radiation damage were observed for electrons and neutrons in both the ternary and unalloyed iron.
Date:
December 22, 1999
Creator:
Alexander, D. E.; Rehn, L. E.; Odette, G. R.; Lucas, G. E.; Klingensmith, D. & Gragg, D.
Object Type:
Article
System:
The UNT Digital Library
Electron channeling X-ray microanalysis for cation configuration in irradiate magnesium aluminate spinel
High angular resolution electron channeling X-ray spectroscopy (HARECXS) was examined as a practical tool to locate lattice-ions in spinel crystals. The orientation dependent intensity distribution of emitted X-rays obtained by HARECXS is so sensitive to lattice-ion configuration in the illuminated areas that the occupation probabilities on specific positions in the crystal lattice can be determined accurately through comparison with the theoretical rocking curves. HARECXS measurements have revealed partially disordered cation arrangement in MgO{center_dot}nAl{sub 2}O{sub 3} with n = 1.0 and 2.4. Most Al{sup 3+} lattice-ions occupy the octahedral (VIII) sites, while Mg{sup 2} lattice-ions reside on both the tetrahedral (IV) and the octahedral (VIII) sites. The structural vacancies are enriched in the IV-sites. Further evacuation of cations from the IV-sites to the VIII-sites is recognized in a disordering process induced by irradiation with 1 MeV Ne{sup +} ions up to 8.9 dpa at 870 K.
Date:
December 22, 1999
Creator:
Matsumura, S.; Soeda, T.; Zaluzec, N. J. & Kinoshita, C.
Object Type:
Article
System:
The UNT Digital Library
Evaluation of plasma-sprayed CoS{sub 2} cathodes for thermal batteries
Conventional electroactive stack components in thermal batteries are constructed from pressed-powder parts. These include the anode, separator, and cathode pellets (discs). Pressing parts that are less than 0.010 inch thick is difficult. The use of plasma spray to deposit thin CoS{sub 2} cathode films onto a stainless steel substrate was examined as an alternative to pressed-powder cathodes. The plasma-sprayed electrodes were tested in single cells under isothermal conditions and constant-current discharge over a temperature range of 400 C to 550 C using standard LiSi anodes and separators based on the LiCl-KCl eutectic. Similar tests were conducted with cells built with conventional pressed-powder cathodes, which were tested under the same conditions for comparative purposes. This paper presents the results of those tests.
Date:
December 22, 1999
Creator:
Guidotti, R.A.
Object Type:
Article
System:
The UNT Digital Library
Foster Care: States' Early Experiences Implementing the Adoption and Safe Families Act
A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO reviewed the Adoption and Safe Families Act of 1997 (ASFA), focusing on: (1) how states have responded to ASFA regarding legal, administrative, and other changes that social workers may need to make in their day-to-day practice of handling child welfare cases; (2) the status of states' implementation of the two provisions related to making timely permanency decisions for those foster children who are unable to safely return home; and (3) the actions the Department of Health and Human Services (HHS) has taken to assist states and monitor the implementation of these two provisions."
Date:
December 22, 1999
Creator:
United States. General Accounting Office.
Object Type:
Report
System:
The UNT Digital Library
Higgs Mass Determination From Direct Reconstruction at a Linear E+E- Collider
We study the feasibility of a precise measurement of the mass of a 120 GeV MSM Higgs boson through direct reconstruction of ZH {yields} q{bar q}H events that would be achieved in a future e{sup +}e{sup -} linear collider operating at a center-of-mass energy of 500 GeV. Much effort has been put in a ''realistic simulation'' by including irreducible+reducible backgrounds, realistic detector effects and reconstruction procedures and sophisticated analysis tools involving Neural Networks and kinematical fitting. As a result, the Higgs mass is determined with a statistical accuracy of 50 MeV and the Z-Higgs Yukawa coupling measured to 0.7%, assuming 500 fb{sup -1} of integrated luminosity.
Date:
December 22, 1999
Creator:
Juste, A.
Object Type:
Article
System:
The UNT Digital Library
Laser modulated scattering as a nondestructive evaluation tool for optical surfaces and thin film coatings
Laser modulated scattering (LMS) is introduced as a non-destructive evaluation tool for defect inspection and characterization of optical surfaces and thin film coatings. This technique is a scatter sensitive version of the well-known photothermal microscopy (PTM) technique. It allows simultaneous measurement of the DC and AC scattering signals of a probe laser beam from an optical surface. By comparison between the DC and AC scattering signals, one can differentiate absorptive defects from non-absorptive ones. This paper describes the principle of the LMS technique and the experimental setup, and illustrates examples on using LMS as a tool for nondestructive evaluation of high quality optics.
Date:
December 22, 1999
Creator:
Feit, M D; Kozlowski, M R; Rubenchik, A M; Sheehan, L & Wu, Z L
Object Type:
Article
System:
The UNT Digital Library
Mechanistic study of dielectric chemical mechanical polishing by spectral and scaling analysis of atomic force microscope images
Thermal oxide and PETEOS oxide surfaces, polished on an IPEC 472 with different combinations of polish pad, slurry, and polishing conditions, were studied with ex situ atomic force microscopy. The post polish surfaces were analyzed qualitatively by visual inspection and quantitatively by spectral and scaling analyses. Spectral and scaling analyses gave consistent interpretations of morphology evolution. Polishing with either a fixed abrasive pad or alumina-based slurry occurred via a mechanism for which asperities are removed and recesses are filled. A sputtering-type mechanism may contribute to material removal when polishing with silica- or ceria-based slurries.
Date:
December 22, 1999
Creator:
Verhoff, M.L.
Object Type:
Article
System:
The UNT Digital Library
A Novel Approach to Material Development for Advanced Reactor Systems
OAK B188 A Novel Approach to Material Development for Advanced Reactor Systems. Year one of this project had three major goals. First, to specify, order and install a new high current ion source for more rapid and stable proton irradiation. Second, to assess the use low temperature irradiation and chromium pre-enrichment in an effort to isolate a radiation damage microstructure in stainless steels without the effects of RIS. Third, to prepare for the irradiation of reactor pressure vessel steel and Zircaloy. In year 1 quarter 1, the project goal was to order the high current ion source and to procure and prepare samples of stainless steel for low temperature proton irradiation.
Date:
December 22, 1999
Creator:
Was, G.S.; Atzmon, M. & Wang, L.
Object Type:
Report
System:
The UNT Digital Library
Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-PbTiO{sub 3} thin films synthesized by metalorganic chemical vapor deposition
Metalorganic chemical vapor deposition was used to synthesize epitaxial Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}{minus}PbTiO{sub 3} films on SrTiO{sub 3} and SrRuO{sub 3}/SrTiO{sub 3} substrates, using solid Mg(DPM){sub 2} as the Mg precursor. Depositing conditions have been identified under which phase-pure perovskite PMN-PT may be grown. In contrast, in lead-poor environments, an additional second phases of a disordered magnesium-niobium oxide has tentatively been identified. X-ray diffraction and selected area electron diffraction indicate a cube-on-cube orientation relationship between film and substrate, with a (001) rocking curve width of 0.1{degree}, and in-plane mosaic of 0.8{degree}. The rms surface roughness of a 200nm thick PMN film on SrTiO{sub 3} was 2 to 3 nm as measured by scanned probe microscopy. The zero-bias dielectric constant and loss measured at room temperature and 10 kHz for a 350 nm thick pure PMN film on SrRuO{sub 3}/SrTiO{sub 3} were 1100 and 2%, respectively. Small-signal permittivity ranged from 900 to 1400 depending on deposition conditions and Ti content; low values for the dielectric loss between 1 and 3% were determined for all specimens. Here the authors report on growth conditions and the initial structural and dielectric characterization of these samples.
Date:
December 22, 1999
Creator:
Streiffer, S. K.; Bai, G. R.; Auciello, O.; Baumann, P. K.; Ghosh, K.; Munkholm, A. et al.
Object Type:
Article
System:
The UNT Digital Library
Rare B decays, mixing and cp violation at the Fermilab Tevatron
Over two decades since its discovery at Fermilab in 1977, the b quark has become an important laboratory for the exploration of the Standard Model as well as a potential window beyond it. Its kinematic properties, its large mass and long lifetime, and its large production cross section in hadron collisions, make it an excellent subject of study at the Tevatron {bar p}p collider. In this article, we will review recent results from CDF and D0 in two categories of tests of the Standard Model: the search for rare b decays, and the measurement of asymmetry parameters related to B{sup 0} meson mixing and CP violation. The detectors have been described elsewhere. The data for the results presented here are from the 1992-96 collider run, representing at each experiment, approximately 100 pb{sup -1} of integrated luminosity at {radical}s = 1.8 TeV.
Date:
December 22, 1999
Creator:
Tseng, J.
Object Type:
Article
System:
The UNT Digital Library
Recent Results from CDF
We present the latest results from the CDF experiment at the Tevatron Collider in p{bar p} collisions at {radical}s = 1.8 TeV. The large data sample collected during Run 1, from 1992 until 1995, allows measurements in many domains of high-energy physics. Here, we report on the first measurement of sin(2{beta}), a CP violation parameter, and on an improved measurement of the top quark cross section. We also report on searches for the so-far elusive Higgs boson, and for SUSY, through searches for direct production of top and bottom scalar quarks. Finally, we outline the prospects for the physics during the upcoming Run 2, ready to start in the upcoming year 2000.
Date:
December 22, 1999
Creator:
Gallinaro, Michele
Object Type:
Article
System:
The UNT Digital Library
Securities and Exchange Commission: Adoption of Amendments to the Intermarket Trading System Plan to Expand the ITS/Computer Assisted Execution System Linkage to All Listed Securities
Other written product issued by the General Accounting Office with an abstract that begins "Pursuant to a legislative requirement, GAO reviewed the Securities and Exchange Commission (SEC) new rule on amending the Intermarket Trading System Plan. GAO noted that: (1) the final rule amends the plan governing the operation of the Intermarket Trading System; and (2) SEC complied with the applicable requirements in promulgating the rule."
Date:
December 22, 1999
Creator:
United States. General Accounting Office.
Object Type:
Text
System:
The UNT Digital Library
Subcontractor Complaints Concerning the D.C. Union Station Renovation Project
Correspondence issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO provided information regarding work done on the Union Station Redevelopment Project by Park Woodworking, Inc., focusing on the: (1) extent of the government's liability, if any, for costs incurred for which Park was not compensated; (2) extent to which Park was not compensated for the work it did; and (3) actions taken by the Secretary of Transportation and the Department of Transportation (DOT) Inspector General (IG) in response to complaints received from Park."
Date:
December 22, 1999
Creator:
United States. General Accounting Office.
Object Type:
Text
System:
The UNT Digital Library
Telecommunications Discounts for Schools and Libraries: The “E-Rate” Program and Controversies
None
Date:
December 22, 1999
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
Temperature dependence of ion irradiation induced amorphization of zirconolite
Zirconolite is one of the major host phases for actinides in various wasteforms for immobilizing high level radioactive waste (HLW). Over time, zirconolite's crystalline matrix is damaged by {alpha}-particles and energetic recoil nuclei recoil resulting from {alpha}-decay events. The cumulative damage caused by these particles results in amorphization. Data from natural zirconolites suggest that radiation damage anneals over geologic time and is dependant on the thermal history of the material. Proposed HLW containment strategies rely on both a suitable wasteform and geologic isolation. Depending on the waste loading, depth of burial, and the repository-specific geothermal gradient, burial could result in a wasteform being exposed to temperatures of between 100--450 C. Consequently, it is important to assess the effect of temperature on radiation damage in synthetic zirconolite. Zirconolite containing wasteforms are likely to be hot pressed at or below 1,473 K (1,200 C) and/or sintered at or below 1,623 K (1,350 C). Zirconolite fabricated at temperatures below 1,523 K (1,250 C) contains many stacking faults. As there have been various attempts to link radiation resistance to structure, the authors decided it was also pertinent to assess the role of stacking faults in radiation resistance. In this study, they simulate {alpha}-decay damage …
Date:
December 22, 1999
Creator:
Smith, K. L.; Blackford, M. G.; Lumpkin, G. R. & Zaluzec, N. J.
Object Type:
Article
System:
The UNT Digital Library