The sintering of ZnO varistor precursor powders, doped with Co, Mn and different concentrations of Bi and Al, is investigated and discussed in relation with sintering models. One purpose of the present study is to provide information valuable for the fabrication of high field varistors. As the fundamental parameter of these electronic components is the breakdown voltage per unit of thickness, which is determined by the number of grain boundaries per linear dimension, the grain size and the sintered density are crucial variables, and the sintering is a central step in the manufacturing of such varistors. Sintering experiments performed at constant heating rate in a loading dilatometer provide data on the densification and creep of the compacted powders. Another goal of the present study is to provide an experimental basis for the interpretation of the evolution of the ratio between densification rate and creep rate in terms of competition between densification and microstructure coarsening. This is accomplished by taking advantage of the variety of sintering behaviors that takes place in the system ZnO-Bi-Al: the comparison of these behaviors allows us to correlate the macroscopic sintering parameters to the evolution of the microstructure. It results that, while in non-doped powders densification …

Annual report of the Texas Research League describing goals, activities, and accomplishments during fiscal year 1989.

Biweekly, comprehensive compilation of decisions, reports, public notices, and other documents of the U.S. Federal Communications Commission.

This report presents the goals of the Theoretical Ecology Program and abstracts of research in progress. Abstracts cover both theoretical research that began as part of the terrestrial ecology core program and new projects funded by the theoretical program begun in 1988. Projects have been clustered into four major categories: Ecosystem dynamics; landscape/scaling dynamics; population dynamics; and experiment/sample design.

This report describes Kesterson Reservoir related research activities carried out under a cooperative program between Lawrence Berkeley Laboratory and the Division of Agriculture and Natural Resources at the University of California during FY89. The primary objectives of these investigations are: Predict the extent, probability of the occurrence, and selenium concentrations in surface water of temporary wetland habitat at Kesterson; assess rates and direction of migration of the drainage water plume that seeped into the aquifer under Kesterson; monitor and predict changes in quantity and speciation of selenium in surface soils and vadose zone pore-waters; and develop a comprehensive strategy through soil, water, and vegetation management to safely dissipate the high concentrations of selenium accumulated in Kesterson soils. This report provides an up-date on progress made in each of these areas. Chapter 2 describes results of recent investigations of water table fluctuations and plume migration. Chapter 3 describes results of ongoing monitoring of soil water selenium concentrations and evaporative accumulation of selenium at the soil surface. Chapter 4 describes early results from the soil, water, and vegetation management field trials as well as supporting laboratory and theoretical studies. In Chapter 5, new analytical methods for selenium speciation are described and quality …

A four day review to assess the status of target physics of inertial confinement fusion was held at US Department of Energy (DOE) Headquarters on November 14--17, 1988. This review completes the current series of reviews of the inertial fusion program elements to assess the status of the data base for a decision to proceed with the proposed Laboratory Microfusion Facility (LMF) that is being planned. In addition to target physics, the program elements that have been reviewed previously include the driver technology development for KrF and solid-state lasers, and the light-on beam pulsed power system. This series of reviews was undertaken for internal DOE assessment in anticipation of the ICF program review mandated by the Congress in 1988 to be completed in 1990 to assess the significance and implications of the progress that has been realized in the laboratory and the underground Halite/Centurion experiments. For this target physics review, both the direct and the indirect drive approaches were considered. The principal issues addressed in this review were: Is the present target physics data base adequate for a decision to proceed with design and construction of LMF now as opposed to continue planning activities at this time What specific additional …

Newsletter published by the Texas Department of Transportation for TxDOT employees including information about the organization, projects throughout the state, and other topics related to transportation in Texas.

Newsletter of the Lyndon B. Johnson School of Public Affairs at the University of Texas at Austin, describing programs in the school and current events related to local, national, and international affairs and policies.

This report discusses concerns safety issues, and management at Hanford Tank Farm. Concerns center on the issue of flammable gas generation which could ignite, and on possible exothermic reactions of ferrocyanide compounds which were added to single shell tanks in the 1950's. It is believed that information concerning these issues has been mis-handled and the problems poorly managed. (CBS)

From abstract: At the request of the U.S. Bureau of Land Management, approximately 19,300 acres of the Black Mountains North Wilderness Study Area (AZ-020-009) and 23,310 acres of the Burns Spring Wilderness Study Area (AZ-020-010) were evaluated for mineral resources and mineral resource potential. In this report, the area studied is referred to, collectively or individually, as the 'wilderness study area' or simply 'the study area'; any reference to the Black Mountains North or Burns Spring Wilderness Study Areas refers only to that part of the wilderness study area for which a mineral survey was requested by the U.S. Bureau of Land Management. The study area is located in western Arizona, about 30 mi northwest of Kingman. There are no identified resources in the study area.

Book commemorating Family Land Heritage Day with descriptions of the honorees from 1986 to 1990 -- including important dates, people, and biographical information -- along with an index and other related information.

This report describes recent progress in a fundamental, three-year investigation of carbon formation and its effects on the activity and selectivity of promoted iron catalysts for synthesis, the objectives of which are: determine rates and mechanisms of carbon deactivation of unsupported Fe and Fe/K catalysts during CO hydrogenation over a range of CO concentrations, CO:H{sub 2} ratios, and temperatures; model the rates of deactivation of the same catalysts in fixed-bed reactors. During the fourteenth quarter design of software for a computer-automated reactor system to be used in the kinetic and deactivation studies was continued. Further progress was made toward the completion of the control language, control routines, and software for operating this system. Progress was also made towards testing of the system hardware and software. 47 refs.

A new microwave electron cyclotron resonance (ECR) multicusp plasma ion source that has two ECR plasma production regions and uses multicusp plasma confinement has been developed at Oak Ridge National Laboratory. This source has been operated to produce uniform and dense plasma over large areas of 300 to 400 cm{sup 2} and could be scaled up to produce uniform plasma over 700 cm{sup 2} or larger. The plasma source has been operated with continuous argon gas feed and pulsed microwave power. The working gases used were argon, helium, hydrogen, and oxygen. The discharge initiation phenomena and plasma properties have been investigated and studied as functions of the discharge parameters. The discharge characteristics and a hypothetical discharge mechanism for this plasma source are described and discussed. Potential applications, including plasma and ion-beam sources for manufacturing advanced microelectronics, for space electric propulsion, and for fusion research, are discussed. 10 refs., 10 figs.

A system for the detection and measurement of indoor radon progeny activity-weighted size distributions (particle size, d{sub p} > 0.5 nm) and concentration levels has been developed. The system is microcomputer-controlled and involves a combination of multiple wire screen (Graded Screen Array) sampler-detector units operated in parallel. The radioactivity sampled in these units permits the estimation of the radon progeny activity-weighted size distributions and concentration levels on a semi-continuous basis. This paper presents details of the system and describes various stages in the development of the system. Results of field measurements in a residential environment are presented to illustrate the resolution, sensitivity and capabilities of the measurement system. 16 refs., 4 figs., 1 tab.

To investigate the effects of heating on the mineralogical, geochemical, and mechanical properties of rock by high-level radioactive waste, cores are being examined from holes penetrating locations where electric heaters simulated the presence of a waste canister, and from holes penetration natural hydrothermal systems. Results to date indicate the localized mobility and deposition of uranium in an open fracture in heated granitic rock, the mobility of U in a breccia zone in an active hydrothermal system in tuff, and the presence of U in relatively high concentration in fracture-lining material in tuff. Mechanical -- property studies indicate that differences in compressional- and shear-wave parameters between heated and less heated rock can be attributed to differences in the density of microcracks. Emphasis has shifted from initial studies of granitic rock at Stripa, Sweden to current investigations of welded tuff at the Nevada Test Site. 7 refs., 8 figs.

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The phenomenon of hot cracking is described and discussed, and criteria for tests to assess hot cracking are elucidated. The historical development of hot cracking tests is traced from the 1930s to present, with categorization of tests into several types. It is noted that the number of tests developed continues to increase dramatically. The number of literature citations also increases with time, with few popular tests receiving a major share of interest. Predominant countries of origin of both tests and citations shift with time, and a few journals account for most of the published information. Reviews of hot cracking are reviewed, and it is predicted that modeling and other developing analytical techniques will contribute greatly to an increase in our understanding of hot cracking. 30 refs., 10 figs., 1 tab.

Annual index to cases decided by the Texas Supreme Court, organized by names and case/citation numbers, along with locations where the microfiche of the complete case opinions may be accessed.

Newsletter of the Texas Hunter Education Program discussing various events, news, and other information related to the program or of interest to hunters in Texas.

We investigated a new continuum {gamma}-ray spectroscopy technique which is based on the detection of all emitted {gamma} rays in a 4{pi} detector system, and ordering them according to their energies on an event-by-event basis. The technique allows determination of growth strength functions, and rotational damping width as a function of spin and temperature. Thus, it opens up the possibility of studying the onset of motional narrowing and the mapping of the evolution of nuclear collectivity with spin and temperature. Application of the technique for preferential entry-state population, exit-channel selection, and feeding of the discrete states via selective pathways will be discussed. 19 refs., 6 figs.

This report discusses the following topics: neutron starts, pulsars, and dense baryonic matter, intermittency and other correlations; fractional statistics; and electroweak theory.

the travelers attended the Fifth International Congress of Ecology (INTECOL) in Yokohama, Japan, and two presented invited papers and chaired symposia. One traveler also attended the OJI International Seminar in Gifu, Japan and the Fukuoka Symposium on Theoretical Ecology in Fukuoka, Japan and presented invited papers. At these scientific gatherings, a large number of symposia and specific presentations were relevant to current research at Oak Ridge National Laboratory (ORNL), especially in the areas of landscape dynamics, plant physiology, and aquatic ecosystems.

This report describes recent progress in a fundamental, three-year investigation of carbon formation and its effects on the activity and selectivity of promoted iron catalysts for Fischer-Tropsch (FT) synthesis, the objectives of which are: determine rates and mechanisms of carbon deactivation of unsupported Fe and Fe/K catalysts during CO hydrogenation over a range of CO concentrations, CO:H{sub 2} ratios, and temperatures; model the rates of deactivation of the same catalysts in fixed-bed reactors. During the thirteenth quarter design of software for a computer-automated reactor system to be used in the kinetic and deactivation studies was continued. Further progress was made toward the completion of the control language, control routines, and software for operating this system. Progress was also made on the testing of the system hardware and software. H{sub 2} chemisorption capacities and activity selectivity data were also measured for three iron catalysts promoted with 1% alumina. 47 refs., 8 figs., 1 tab.

We review the published data on the optical properties of beryllium for the spectral region from 0.03 to 300 eV. In the visible and infrared spectral regions, where published data from various authors show very large variations, we have performed experiments that identify the most probable sources of error, and use this information to select the best data from published sources. The effects of surface oxide overlayers have also been studied. In the far infrared spectral region, where only normal incidence reflectance data are available, and in the extreme ultraviolet, where only transmission data are available, there is insufficient information to fully determine the optical properties at each photon energy. Between 0.06 and 26 eV, however, a normal incidence reflectance curve is fully determined. This curve has been used for a Kramers{endash}Kronig analysis to determine the optical properties in this spectral range. 10 refs., 13 figs., 3 tabs.