An exact renormalization model for earthquakes and material failure: Statics and dynamics (open access)

An exact renormalization model for earthquakes and material failure: Statics and dynamics

Earthquake events are well-known to prams a variety of empirical scaling laws. Accordingly, renormalization methods offer some hope for understanding why earthquake statistics behave in a similar way over orders of magnitude of energy. We review the progress made in the use of renormalization methods in approaching the earthquake problem. In particular, earthquake events have been modeled by previous investigators as hierarchically organized bundles of fibers with equal load sharing. We consider by computational and analytic means the failure properties of such bundles of fibers, a problem that may be treated exactly by renormalization methods. We show, independent of the specific properties of an individual fiber, that the stress and time thresholds for failure of fiber bundles obey universal, albeit different, staling laws with respect to the size of the bundles. The application of these results to fracture processes in earthquake events and in engineering materials helps to provide insight into some of the observed patterns and scaling-in particular, the apparent weakening of earthquake faults and composite materials with respect to size, and the apparent emergence of relatively well-defined stresses and times when failure is seemingly assured.
Date: September 12, 1993
Creator: Newman, W. I.; Gabrielov, A. M.; Durand, T. A.; Phoenix, S. L. & Turcotte, D. L.
Object Type: Article
System: The UNT Digital Library
High-order sum and difference-frequency generation in helium (open access)

High-order sum and difference-frequency generation in helium

High-order harmonic generation provides a new method for generating coherent, XUV radiation. These harmonics are characterized by a rapid, pertubative drop at low orders, followed by a broad plateau extending to photon energies of 150 eV in the lighter, rare gas atoms. An experimentally observed limit coincides with the theoretical limit for harmonic generation in neutral atoms given by the expression E{sub c}(eV)=IP(0)+3U{sub p}(I), where E{sub c} is the energy cutoff of the harmonic plateau, IP(O) is the field-free ionization potential and U{sub p} is the electron quiver energy at the maximum intensity, I seen by the atom. As part of an effort to develop this technique into a general purpose XUV source, extensive work to understand the phase-matching between the harmonic and driving fields, and the resulting effect on the conversion efficiency, angular distribution and spectral brightness has been undertaken at several. Though, certain aspects of the harmonically generated radiation such as the polarization, relative strength of a given harmonic, and the plateau extent, are defined by the single atom-field interaction. Specifically, the single-atom harmonic spectrum is determined primarily by the interaction of a driven, quasi-free electron with the atomic potential. Using two, independent fields one can affect the …
Date: May 12, 1993
Creator: Crane, J. K. & Perry, M. D.
Object Type: Article
System: The UNT Digital Library
The Holdup Measurement System II (HMSII) (open access)

The Holdup Measurement System II (HMSII)

A project is in progress that addresses two of the problems with existing holdup measurement technology: the need for compact instrumentation and a more efficient means of reducing the massive amounts of data to quantities of Special Nuclear Materials (SNM). The approach taken by the project utilizes the Miniature Modular MultiChannel Analyzer (M{sup 3}CA), a complete and truly portable gamma-ray spectroscopy system, under development at Los Alamos National Laboratory. The hardware is then integrated and automated by the Holdup Measurement System II (HMSII) software being developed by the Oak Ridge Y-12 Plant. Together they provide the hardware components, measurement control in the field, automated data acquisition, data storage and manipulation which simplify holdup measurements.
Date: July 12, 1993
Creator: Smith, S. E.; Gibson, J. S.; Halbig, J. K.; Klosterbuer, S. F.; Russo, P. A. & Sprinkle, J. K. Jr.
Object Type: Article
System: The UNT Digital Library
The front-end electronics for the L3 Silicon Microvertex Detector (open access)

The front-end electronics for the L3 Silicon Microvertex Detector

The L3 detector, located at the LEP storage ring at CERN (European Center for Nuclear Research), has recently installed a silicon microvertex detector (SMD). The purpose of the SMD is to enhance the tracking capabilities of L3 and to provide increased vertex measurement precision for tagging b-jets in the search for the Higgs boson, when LEP doubles its center of mass energy for the LEP 200 running. The subject of this article is the fabrication and testing of the front-end electronics for the SMD. The article is organized into several sections. The first section describes the SMD, the second section discusses the front-end electronics, the third section presents the testing procedures and the results of the tests.
Date: August 12, 1993
Creator: Mills, G. B.
Object Type: Article
System: The UNT Digital Library
Accuracy, precision, and lower detection limits (a deficit reduction approach) (open access)

Accuracy, precision, and lower detection limits (a deficit reduction approach)

The evaluation of the accuracy, precision and lower detection limits of the determination of trace radionuclides in environmental samples can become quite sophisticated and time consuming. This in turn could add significant cost to the analyses being performed. In the present method, a {open_quotes}deficit reduction approach{close_quotes} has been taken to keep costs low, but at the same time provide defensible data. In order to measure the accuracy of a particular method, reference samples are measured over the time period that the actual samples are being analyzed. Using a Lotus spreadsheet, data are compiled and an average accuracy is computed. If pairs of reference samples are analyzed, then precision can also be evaluated from the duplicate data sets. The standard deviation can be calculated if the reference concentrations of the duplicates are all in the same general range. Laboratory blanks are used to estimate the lower detection limits. The lower detection limit is calculated as 4.65 times the standard deviation of a set of blank determinations made over a given period of time. A Lotus spreadsheet is again used to compile data and LDLs over different periods of time can be compared.
Date: October 12, 1993
Creator: Bishop, C. T.
Object Type: Article
System: The UNT Digital Library
High Resolution, Three Dimensional Soft X-Ray Imaging (open access)

High Resolution, Three Dimensional Soft X-Ray Imaging

A long term goal of soft x-ray imaging has been to make ultrahigh resolution images of unstained, unprepared, wet, live biological microstructures in physiological normal environments. This is now being accomplished with features as small as 300 {Angstrom} being observed in two dimensional x-ray images. While this achievement is remarkable, most complex biological structures are three dimensional in nature and will require three dimensional images on the few hundred Angstrom scale for the structure-function studies required by modern biology. We have been endeavoring to achieve this three dimensional capability with soft x-ray techniques.
Date: May 12, 1993
Creator: Trebes, J.; Brase, J.; Levesque, R.; Szoke, H.; Yorkey, T.; Anderson, E. et al.
Object Type: Article
System: The UNT Digital Library
Radioactive and industrial waste water collection system study, Phase I (open access)

Radioactive and industrial waste water collection system study, Phase I

None
Date: October 12, 1993
Creator: unknown
Object Type: Report
System: The UNT Digital Library
NASA HSRP Emissions Scenarios Committee meeting, June 7, 1993 (open access)

NASA HSRP Emissions Scenarios Committee meeting, June 7, 1993

This primary purpose of this plan is to establish a process to ensure data integrity in the process of assembling aircraft emission scenario data sets from component data developed and provided by various sources. A component data set is one for a particular aircraft use (i.e. scheduled airline). A scenario data set is an ensemble set for a particular time. A secondary purpose is to help identify possible discrepancies or inconsistencies in the component data sets developed elsewhere or in the scenario data sets. This plan covers activities involved in assembling aircraft emission scenario data sets and by the component data set producers in supplying information to support evaluation of the component data sets. It does not cover work by the data producers to validate their work in developing the component data sets or to establish the fundamental soundness of the component data sets.
Date: August 12, 1993
Creator: Wuebbles, D. J. & Seals, R. M.
Object Type: Report
System: The UNT Digital Library
Nitrogen and carbon oxides chemistry in the HRS retorting process (open access)

Nitrogen and carbon oxides chemistry in the HRS retorting process

The HRS Oil Shale Retort process consists of a pyrolysis section which converts kerogen of the shale to liquid and gaseous products, and a combustion section which burns residual carbon on the shale to heat the process. Average gas concentrations of selected gas phase species were determined from data measured at several placed on the combustion system of the Lawrence Livermore National Laboratory Hot-Recycled-Solids Retort Pilot Plant for representative rich and lean shale runs. The data was measured on-line and in real time by on-line meters (CO{sub 2}, CO, O{sub 2}), mass spectrometry (CO{sub 2}, O{sub 2}, H{sub 2}O, NO, CH{sub 4}, SO{sub 2}, N{sub 2} and Ar), and Fourier transform infrared spectroscopy (CO{sub 2}, CO, H{sub 2}O, NO, N{sub 2}O, NO{sub 2}, CH{sub 4}, SO{sub 2}, NH{sub 3}, and HCN). For both the rich and leans shale runs, the Lift-Pipe Combustor (LFT) exhibited gas concentrations (sampled at the exit of the LFT) indicative of incomplete combustion and oxidation; the Delayed-Fall Combustor (DFC) exhibited gas concentrations (sampled at the annulus and the exit of the DFC) indicative of much more complete combustion and oxidation. The Fluidized-Bed Combustor exhibited gas concentrations which were controlled to a large extent by the injection …
Date: November 12, 1993
Creator: Reynolds, J. G.
Object Type: Report
System: The UNT Digital Library
NCSU PULSTAR Reactor instrumentation upgrade (open access)

NCSU PULSTAR Reactor instrumentation upgrade

The Nuclear Reactor Program at North Carolina State University initiated an upgrade program at the NCSU PULSTAR Reactor in 1990. Twenty-year-old instrumentation is currently undergoing replacement with solid-state and current technology equipment. The financial assistance from the United States Department of Energy has been the primary source of support. This interim report provides the status of the first two phases of the upgrade program.
Date: August 12, 1993
Creator: Perez, P. B. & Bilyj, S. J.
Object Type: Report
System: The UNT Digital Library
Winter Fuels Report: Week Ending November 5, 1993 (open access)

Winter Fuels Report: Week Ending November 5, 1993

The Winter Fuels Report is intended to provide concise, timely information to the industry, the press, policymakers, consumers, analysts, and State and local governments on the following topics: Distillate fuel oil net production, imports and stocks on a US level and for all Petroleum Administration for Defense Districts (PADD) and product supplied on a US level; propane net production, imports and stocks on a US level and for PADD`s I, II, and III; natural gas supply and disposition and underground storage for the US and consumption for all PADD`S; as well as selected National average prices; residential and wholesale pricing data for heating oil and propane for those States participating in the joint Energy Information Administration (EIA)/State Heating Oil and Propane Program; crude oil and petroleum price comparisons for the US and selected cities; and a 6--10 Day, 30-Day, and 90-Day outlook for temperature and precipitation and US total heating degree-days by city.
Date: November 12, 1993
Creator: unknown
Object Type: Report
System: The UNT Digital Library
CAVEMAN: Configuration And VErsion MANagement. User`s guide, v2.1.2 (open access)

CAVEMAN: Configuration And VErsion MANagement. User`s guide, v2.1.2

The mission of the CAVEMAN project is to provide the tools for large code systems so that those who work on them can perform source control and configuration control on UNIX-based file servers, rather than the LC Crays. An outside product called cvs has been chosen as the underlying source control system. The initials stand for {open_quotes}Concurrent Versions System{close_quotes}. It is a freeware program that runs on most UNIX stations. To quote from the cvs man page: {open_quotes}cvs is a front end to the rcs revision control system which extends the notion of revision control from a collection of files in a single directory to a hierarchical collection of directories consisting of revision controlled files. These directories and files can be combined together to form a software release. cvs provides the functions necessary to manage these software releases and to control the concurrent editing of source files among multiple software developers.{close_quotes} While cvs may be run directly, there are several tasks in the LLNL environment that it seemed either safer or easier to automate. CAVEMAN provides the needed functionality, generally in the form of wrappers to cvs.
Date: March 12, 1993
Creator: Dyer, K. M.
Object Type: Report
System: The UNT Digital Library
Advanced Cooling Technology, Inc. final technical progress report (open access)

Advanced Cooling Technology, Inc. final technical progress report

Tasks performed to develop an improved version of Advanced Cooling Technology`s Evaporative Subcooling System are described. Work on pump stability, improved drainage mechanism, and the American Refrigeration Institute engineering performance tests is presented.
Date: August 12, 1993
Creator: Myers, H. S.
Object Type: Report
System: The UNT Digital Library
Simulation of transient effects in the heavy ion fusion injectors (open access)

Simulation of transient effects in the heavy ion fusion injectors

We have used the 2-D PIC code, GYMNOS, to study the transient behaviors in the Heavy Ion Fusion (HIF) injectors. GYMNOS simulations accurately provide the steady state Child-Langmuir current and the beam transient behavior within a planar diode. The simulations of the LBL HIF ESAC injector experiments agree well with the experimental data and EGUN steady state results. Simulations of the nominal HIF injectors have revealed the need to design the accelerating electrodes carefully to control the ion beam current, particularly the ion loss at the end of the bunch as the extraction voltage is reduced.
Date: May 12, 1993
Creator: Chen, Yu-Jiuan & Hewett, D. W.
Object Type: Article
System: The UNT Digital Library
Thermodynamics of computation and information distance (open access)

Thermodynamics of computation and information distance

Applying the tools of algorithmic information theory, we compare several candidates for an asymptotically machine-independent. absolute measure of the informational or ``cognitive`` distance between discrete objects x and y. The maximum of the conditional Kolmogorov complexities max{l_brace}K(y{vert_bar}z) K(m{vert_bar}y){r_brace}, is shown to be optimal, in the sense of being minimal within an additive constant among semicomputable, symmetric, positive semidefinite functions of z and y satisfying a reasonable normalization condition and obeying the triangle intequality. The optimal metric, in turn, differs by at most an additive logarithmic term from the size of the smallest program for a universal reversible computer to transform x into y. This program functions in a `catalytic`` capacity, being retained in the computer before, during, and after the computation. Similarly, the sum of the conditional complexities. K(y{vert_bar}x) + K(x{vert_bar}y), is shown to be equal within a logarithmic term to the minimal amount Of information flowing out and in during a reversible computation in which the program is not retained. Finally. using the physical theory of reversible computation, it is shown that the simple difference K(x) - K(y) is an appropriate (ie universal, antisymmetric, and transitive) measure of the amount of thermodynamic work required to transform string x into …
Date: March 12, 1993
Creator: Bennett, C. H.; Gacs, P.; Li, M.; Vitanyi, P. M. B. & Zurek, W. H.
Object Type: Article
System: The UNT Digital Library
Redshift distortions of galaxy correlation functions (open access)

Redshift distortions of galaxy correlation functions

To examine how peculiar velocities can affect the 2-, 3-, and 4-point correlation functions, we evaluate volume-average correlations for configurations that emphasize and minimize distortions for four different volume-limited samples from each of the CfA, SSRS, and IRAS redshift catalogs. We present the results as the correlation length r{sub 0} and power index {gamma} of the 2-point correlation, {anti {Xi}}{sub 2} = (r{sub 0}/r){sup {gamma}}, and as the hierarchical amplitudes of the 3- and 4-point functions, S{sub 3} = {anti {Xi}}{sub 3}/{anti {Xi}}{sub 2}{sup 2} and S{sub 4} = {anti {Xi}}/{anti {Xi}}{sub 2}{sup 3}. We find a characteristic distortion for {anti {Xi}}{sub 2}: The slope {gamma} is flatter and the correlation length is larger in redshift space than in real space; that is, redshift distortions ``move`` correlations from small to large scales. At the largest scales, extra power in the redshift distribution is compatible with {Omega}{sup 4/7}/b {approx} 1; we find 0.53 {plus_minus} 0.15, 1.10 {plus_minus} 0.16 and 0.84 {plus_minus} 0.45 for the CfA, SSRS and IRAS catalogs. Higher order correlations {anti {Xi}}{sub 3} and {anti {Xi}}{sub 4} suffer similar redshift distortions, but in such a way that, within the accuracy of our analysis, the normalized amplitudes S{sub 3} and …
Date: May 12, 1993
Creator: Fry, J. N. & Gaztanaga, E.
Object Type: Report
System: The UNT Digital Library
Mean importance measures for groups of events in fault trees (open access)

Mean importance measures for groups of events in fault trees

The method of moments is applied to precisely determine the mean values of three importance measures: risk reduction, partial derivative, and variance reduction. Variance reduction calculations, in particular, are significantly improved by eliminating the imprecision associated with Monte Carlo estimates. The three importance measures are extended to permit analyses of the relative importance of groups of basic and initiating events. The partial derivative importance measure is extended by assessing the contribution of a group of events to the gradient of the top event frequency. The group importance measures are quantified for the overall fuel damage equation and for 14 dominant accident sequences from an independent probabilistic safety assessment of the K Production Reactor. This application demonstrates both the utility and the versatility of the group importance measures.
Date: October 12, 1993
Creator: Haskin, F. E.; Huang, Min; Sasser, M. K. & Stack, D. W.
Object Type: Report
System: The UNT Digital Library
Public census data on CD-ROM at Lawrence Berkeley Laboratory. Revision 4 (open access)

Public census data on CD-ROM at Lawrence Berkeley Laboratory. Revision 4

The Comprehensive Epidemiologic Data Resource (CEDR) and Populations at Risk to Environmental Pollution (PAREP) projects, of the Information and Computing sciences Division (ICSD) at Lawrence Berkeley Laboratory (LBL), are using public socioeconomic and geographic data files which are available to CEDR and PAREP collaborators via LBL`s computing network. At this time 89 CD-ROM diskettes (approximately 45 gigabytes) are on line via the Unix file server cedrcd.lbl.gov. Most of the files are from the US Bureau of the Census, and many of these pertain to the 1990 Census of Population and Housing. All the CD-ROM diskettes contain documentation in the form of ASCII text files. In addition, printed documentation for most files is available for inspection at University of California Data and Technical Assistance (UC DATA), tel. (510) 642-6571, or the UC Documents Library, tel. (510) 642-2569, both located on the UC Berkeley Campus. Many of the CD-ROM diskettes distributed by the Census Bureau contain software for PC compatible computers, for easily accessing the data. Shared access to the data is maintained through a collaboration among the CEDR and PAREP projects at LBL, and UC DATA, and the UC Documents Library. LBL is grateful to UC DATA and the UC Documents …
Date: March 12, 1993
Creator: Merrill, D. W.
Object Type: Report
System: The UNT Digital Library
Structural stability of 1100{degree}C heated Pd/k during absorption cycling in protium (open access)

Structural stability of 1100{degree}C heated Pd/k during absorption cycling in protium

Pd/k is a hydride forming packing material which is used in the Thermal Cycling Absorption Process (TCAP). Palladium is supported on kieselguhr to create a packing material which will provide adequate void space to prevent excessive pressure drops and flow restrictions. The use of unsupported palladium would result in blockage of columns and clogging of filters due to the small particle size of unsupported palladium hydride powder. During pilot scale demonstrations, it was noted that the Pd/k packing material had degraded causing severe flow restrictions within the TCAP column. A solution to the problem involved the heating of Pd/k at 1,110{degree}C to strengthen the packing material, and render it more resistant to breakdown. The 1, 100{degree}C heated Pd/k has been shown to be more resistant to mechanical breakdown than the Pd/k prior to heat treatment. Two primary modes of Pd/k particle degradation have been identified: mechanical breakdown caused by particle fluidization and degradation caused by absorption/desorption cycling. Absorption/desorption cycling causes the palladium particles within the packing to expanded and contract upon formation and decomposition of the hydride, respectively. This expansion and contraction causes large localized stresses within the packing material, which if these stresses can not be accommodated within the …
Date: March 12, 1993
Creator: Fisher, I. A.
Object Type: Report
System: The UNT Digital Library
Monosodium titanate particle characterization (open access)

Monosodium titanate particle characterization

A characterization study was performed on monosodium titanate (MST) particles to determine the effect of high shear forces expected from the In-Tank Precipitation (ITP) process pumps on the particle size distribution. The particles were characterized using particle size analysis and scanning electron microscopy (SEM). No significant changes in particle size distributions were observed between as-received MST and after 2--4 hours of shearing. Both as-received and sheared MST particles contained a large percentage of porosity with pore sizes on the order of 500 to 2,000 Angstroms. Because of the large percentage of porosity, the overall surface area of the MST is dominated by the internal surfaces. The uranium and plutonium species present in the waste solution will have access to both interior and exterior surfaces. Therefore, uranium and plutonium loading should not be a strong function of MST particle size.
Date: January 12, 1993
Creator: Chandler, G. T. & Hobbs, D. T.
Object Type: Report
System: The UNT Digital Library
ACE program/UNIX user manual (open access)

ACE program/UNIX user manual

This report the following: How to use the ace program?; Introduction to the ace program; Online command; Define a macro file; Macro commands; Counters and MCA; Counters usage; Counters database; Feedback Counter Database; MCA functions and macro command; X window Interclient Communication; and How to get around in UNIX?
Date: January 12, 1993
Creator: Feng-Berman, S. K.
Object Type: Report
System: The UNT Digital Library
A novel process for methanol synthesis. Progress report, September 1, 1992--November 30, 1992 (open access)

A novel process for methanol synthesis. Progress report, September 1, 1992--November 30, 1992

A bench-scale reactor is being used to conduct studies of the conversion of synthesis gas to methanol (MeOH) in the liquid phase by a novel process. In previous reports, we provided evidence for a two step reaction in series, the carbonylation reaction mainly takng place close and the hydrogenolysis reaction taking place on the surface of the copper chromate. The interaction between the two catalyst enhances the rate of MeOH formation. In the last quarter, we showed that under present operating conditions, the methyl formate (MeOH) concentration is not in equilibrium and hence both the carboxylation and the hydrogenolysis reactions influence the rate of MEOH formation. The activities of other alkali and alkaline earth compounds as catalysts, the effect of water and the controlling reaction in the concurrent synthesis is described in this report.
Date: February 12, 1993
Creator: Tierney, J. W. & Wender, I.
Object Type: Report
System: The UNT Digital Library
Fissile solubility and monosodium titanate loading tests (open access)

Fissile solubility and monosodium titanate loading tests

The solubilities of plutonium and uranium have been determined for alkaline salt solutions having compositions which bound those which will be processed in the In-Tank Precipitation (ITP) process. Loadings of plutonium and uranium onto monosodium titanate (MST) have been determined at temperatures bounding those expected to occur during ITP and using a salt solution which was determined to have the maximum solubility for uranium and plutonium. Fissile loadings increase with decreasing amounts of MST in contact with the salt solutions saturated in plutonium and uranium. At MST concentrations bounding those which are planned for the ITP process, expressions for the maximum loadings (wt %) are determined to be 0.29 - 0.20x[MST] for plutonium and 1.8 - 0.29x[MST] for uranium, where [MST] is the concentration of MST in grams/liter. These expressions are valid over the range of MST concentrations from 0.05 to 0.51 g/L and temperatures of 17{degrees}--74{degrees}C. These loadings are below the individual infinitely safe limits for plutonium and uranium. Additional confirmatory experiments are planned to verify the effects of temperature and multiple contacts of the MST with fresh salt solution on the fissile loadings.
Date: February 12, 1993
Creator: Hobbs, D. T. & Fleischman, S. D.
Object Type: Report
System: The UNT Digital Library
The PACSAT Communications Experiment (PCE). Final report, August 13, 1990--February 12, 1992 (open access)

The PACSAT Communications Experiment (PCE). Final report, August 13, 1990--February 12, 1992

While VITA (Volunteers in Technical Assistance) is the recognized world leader in low earth orbiting (LEO) satellite technology (below 1 GHz), its involvement in communications technologies is to facilitate renewable energy technology transfer to developing countries. A communications payload was incorporated into the UoSat 2 satellite (Surrey Univ., UK), launched in 1984; a prototype satellite (PCE) was also launched Jan 1990. US DOE awarded a second grant to VITA to design and test the prototype ground stations (command and field), install field ground stations in several developing country sites, pursue the operational licensing process, and transfer the evaluation results to the design of an operating system. This report covers the principal tasks of this grant.
Date: February 12, 1993
Creator: unknown
Object Type: Report
System: The UNT Digital Library