Several new types of silicon-containing preceramic polymers, i.e., poly(diorganosilacetylene) and poly(diorganosilvinylene) have been synthesized with molecular weights from 10,000 to 120,000. These polymers could be thermally converted to SiC with a moderate to high char yields. Ready solubility and good processability made these types of polymers attractive in their applications to ceramics. The thermal polymerization of diethynyldiphenyl-silane, which was reported in 1968 to afford poly(diphenylsilyldiacetylene) via dehydrogenation, was reinvestigated. Spectroscopic studies showed that the polymer had a structure of polyacetylene type not diacetylene. Diphenyldiethynylgermane and a series of diorganodiethynylsilances were synthesized. These could be polymerized in the presence of MoCl{sub 5} or WCl{sub 6} to afford a soluble, violet material with Mw as high as 108,000. 100 refs., 56 figs., 16 tabs.

An exhaustive study was conducted to determine the feasibility of Nernst-type oxygen sensors based on ceramics containing Bi{sub 2}O{sub 3}. The basic sensor design consisted of a ceramic sensing module sealed into a metal tube. The module accommodated an internal heater and thermocouple. Thermal-expansion-matched metals, adhesives, and seals were researched and developed, consistent with sequential firings during sensor assembly. Significant effort was devoted to heater design/testing and to materials' compatibility with Pt electrodes. A systematic approach was taken to develop all sensor components which led to several design modifications. Prototype sensors were constructed and exhaustively tested. It is concluded that development of Nerst-type oxygen sensors based on Bi{sub 2}O{sub 3} will require much further effort and application of specialized technologies. However, during the course of this 3-year program much progress was reported in the literature on amperometric-type oxygen sensors, and a minor effort was devoted here to this type of sensor based on Bi{sub 2}O{sub 3}. These studies were made on Bi{sub 2}O{sub 3}-based ceramic samples in a multilayer-capacitor-type geometry and amperometric-type oxygen sensing was demonstrated at very low temperatures ({approximately} 160{degree}C). A central advantage here is that these types of sensors can be mass-produced very inexpensively ({approximately} 20--50 cents …

This report considers the use of a dielectric slab undergoing total internal reflection as an accelerating structure for charged particle beams. We examine the functional dependence of the electromagnetic fields above the surface of the dielectric for polarized incident waves. We present an experimental arrangement for testing the performance of the method, using apparatus under construction for the Grating Acceleration experiment at Brookhaven National Laboratory. 13 refs., 4 figs., 2 tabs.

Tasks reported on this term include optimization of chlorided Pt- alumina catalysts, testing of the optimum Pt/Cl alumina catalysts, preparation and testing of zirconia superacid catalyst. (VC)

We present a first principles method for calculating positron lifetimes in solids, based on self-consistent calculations using the Linear Muffin-Tin Orbital method. Local density approximations are used for both electron-electron and electron-positron interactions. Results are presented for a variety of elemental metals and vacancies to demonstrate the reliability of this approach. Theoretical calculations of positron lifetimes can be used to interpret experimental data. As an examples of this, we interpret our experimental lifetime data for the oxide superconductor Ba{sub 1-x}K{sub x}BiO{sub 3} using calculations based on this method. 12 refs., 3 figs.

In this report, we present an improved, feasible and potentially cost effective method of cleaning and beneficiating ultrafine coal. Increased mechanization of mining methods and the need towards depyritization, and demineralization have led to an increase in the quantity of coal fines generated in recent times. For example, the amount of {minus}100 mesh coal occurring in coal preparation plant feeds now typically varies from 5 to 25% of the total feed. Environmental constraints coupled with the greatly increased cost of coal have made it increasingly important to recover more of these fines. Our method chemically modifies the surface of such coals by a series of gaseous phase treatments employing Friedel-Crafts reactions. By using olefins (ethene, propene and butene) and hydrogen chloride catalyst at elevated temperature, the surface hydrophobicity of coal is enhanced. This increased hydrophobicity is manifest in surface phenomena which reflect conditions at the solid/liquid interphase (zeta potential) and those which reflect conditions at the solid/liquid/gas interphases (contact angle, wettability and floatability).

This article summarizes our current understanding of hydrodynamic instabilities as relevant to ICF. First we discuss classical, single mode Rayleigh-Taylor instability, and nonlinear effects in the evolution of a single mode. Then we discuss multimode systems, considering: (1) the onset of nonlinearity; (2) a second order mode coupling theory for weakly nonlinear effects, and (3) the fully nonlinear regime. Two stabilization mechanisms relevant to ICF are described next: gradient scale length and convective stabilization. Then we describe a model which is meant to estimate the weakly nonlinear evolution of multi-mode systems as relevant to ICF, given the short-wavelength stabilization. Finally, we discuss the relevant code simulation capability, and experiments. At this time we are quite optimistic about our ability to estimate instability growth on ICF capsules, but further experiments and simulations are needed to verify the modeling. 52 refs.

The main objectives of this proposed research work are to refine further the inverse liquid chromatography technique for the study of surface properties of raw coals, treated coals and coal minerals in water, to evaluate relatively surface properties of raw coals, treated coals and coal minerals by inverse liquid chromatography, and to evaluate flotability of various treated coals in conjunction with surface properties of coals. Coals such as Pittsburgh seam coal, Illinois No. 6 coal, Wyodak coal are chosen as representatives of high-rank bituminous coal, high volatile bituminous coal and subbituminous coal, respectively. Coal minerals such as pyrite and dolomite are chosen as representative coal minerals.

Correspondence issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO reviewed the audit report covering the financial statements of the United States Olympic Committee for the year ended December 31, 1997, focusing on whether the audit report complied with the financial reporting requirements of the law."

A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a legislative requirement, GAO reviewed the Department of Energy's (DOE) community assistance program for minimizing the impact of downsizing its contractor workforce, focusing on: (1) how much funding DOE had committed to spend and spent in support of its worker and community assistance program for fiscal years (FY) 1994 through 1998; (2) who received benefits during FY 1997 and FY 1998; (3) comparing DOE's separation benefits with the benefit packages of other federal and nonfederal organizations; and (4) what effect DOE's criteria had on determining which communities received assistance."

A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a legislative requirement, GAO reviewed the scientific and practical aspects of a terrorist carrying out large-scale chemical or biological attacks on U.S. soil, focusing on the: (1) technical ease or difficulty for terrorists to acquire, process, improvise, and disseminate certain chemical and biological agents; and (2) extent to which the U.S. government has assessed the threats and risks posed by chemical and biological terrorism in the United States to serve as a basis for planned investments."

Correspondence issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO reviewed the audit report covering the financial statements of the Women's Army Corps Veterans Association for the fiscal year June 30, 1998, focusing on whether the audit report complied with the financial reporting requirements of the law."

Correspondence issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO provided information related to the June 22, 1999, hearing on the nomination of Richard C. Holbrooke to be Ambassador to the United Nations, focusing on United Nations reform issues related to: (1) organizational restructuring; (2) reducing overhead; (3) development dividend; (4) the oversight and monitoring of program effectiveness; (5) sunset provisions for program mandates; and (6) personnel."

Correspondence issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO provided a timeline of events and communications related to the District of Columbia (DC) Courts' fiscal year 1998 financial issues."

Correspondence issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO provided information on Custom Service's Merchandise Processing Fee (MPF) that is charged on certain imports, focusing on the relationship between the fee and the cost of services provided."

A statement of record issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO discussed the Air Force's F-22 aircraft development and procurement program."

A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO provided information on inpatient and residential treatment facilities' use of restraints or seclusion as a means of treating mental patients, focusing on the: (1) dangers of restraint and seclusion, the extent to which restraint and seclusion are used in inpatient and residential treatment facilities for individuals with mental illness or mental retardation, and the number of related injuries and deaths; (2) federal and state policies that govern the use of restraint and seclusion in inpatient or residential treatment facilities for individuals with mental illness or mental retardation; and (3) experiences of states that have instituted regulations and reporting requirements to address the use of restraint and seclusion."

A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO reviewed the crime technology assistance provided by the federal government to state and local law enforcement agencies for fiscal years 1996 through 1998, focusing on the types and amounts of assistance provided by the Department of Justice (DOJ), the Department of the Treasury, and the Office of National Drug Control Policy (ONDCP)."

A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO reviewed the Department of Agriculture's (USDA) efforts to educate farmers about risk management, focusing on: (1) the extent of farmers' use of risk management tools; and (2) educational programs and projects USDA has directed or initiated to prepare farmers for managing risks and determining the groups or individuals who have participated in or been served by these programs."

A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a legislative requirement, GAO examined the General Services Administration's (GSA) retail packaging products program, focusing on whether: (1) GSA is required by law to set its prices for retail packaging products at levels sufficient to ensure that all selling costs are recovered on each item; and (2) GSA's selling prices for these items do recover all costs."

A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO reviewed the Department of Energy's (DOE) progress in implementing performance-based contracting at its national laboratories, focusing on: (1) the status of performance-based contracting in DOE's national laboratory contracts; and (2) DOE's efforts to determine the impact of performance-based contracting."

A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO provided information on the Department of Transportation's (DOT) performance plan for fiscal year (FY) 2000, focusing on: (1) the usefulness of DOT's plan in providing a clear picture of intended performance across the Department; (2) the strategies and resources that DOT will use to achieve its goals; and (3) whether DOT's performance information will be credible."

Other written product issued by the General Accounting Office with an abstract that begins "Pursuant to a legislative requirement, GAO reviewed the Environmental Protection Agency's (EPA) new rule on emission standards for new nonroad spark-ignition nonhandheld engines. GAO noted that: (1) the rule would control emissions from new nonroad spark-ignition nonhandheld engines at or below 19 kilowatts, which are principally used in lawn and garden equipment; and (2) EPA complied with applicable requirements in promulgating the rule."

A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO reviewed the Department of Agriculture's (USDA) performance plan for fiscal year (FY) 2000, focusing on the extent to which the plan: (1) provides a clear picture of intended performance across the Department; (2) discusses the strategies and resources USDA will use to achieve its goals; and (3) provides confidence that the performance information will be credible."