Major improvements in the structural and electrical perfection of single crystals of III-V compound semiconductors have been achieved by using new vertical Bridgman-type and vertical gradient freeze techniques. A general review of experimental set-ups used for growth of large diameter crystals of GaP, InP and GaAs is presented. Crystal properties and characteristic features are discussed to illustrate advantages and disadvantages of the vertical Bridgman-type growth techniques. 22 refs., 5 figs.

The general objective is to improve the knowledge about the transferring processes leading from airborne radon/radon daughters to embedded Po-210 in hard surfaces in the indoor environment. The specific goal of the research is to identify situations in which the surface activity of Po-210 can be used as a long-term indicator of lung cancer risk from past or future radon exposures.

The Kesterson Reservoir was planned as a regulating facility to control drainage water discharges into the San Joaquin-Scaramento River Delta from the San Luis Drain'' which was to dispose of salt-ladin agricultural water. Anticipated environmental impacts of the Kesterson operations focused almost exclusively on problems related to seepage and water-logging of nearby lands. Reuse of drainage water for wetlands focused on excessive salinity. Drainage water entered the reservoir in 1978. By 1983 elevated levels of selenium were found with selenium poisoning causing deformed embryos of water birds, adult bird mortality and their poor reproductive success. An estimated 9000 kg of selenium was delivered to Kesterson between 1981 to 1986. This paper details the chronology of the Kesterson crisis and environmental remediation. 20 refs., 1 fig. (BJN)

The Advanced Neutron Source (ANS) is a new, world class facility for research using hot, thermal, cold, and ultra-cold neutrons. At the heart of the facility is a 350-MW{sub th}, heavy water cooled and moderated reactor. The reactor is housed in a central reactor building, with supporting equipment located in an adjoining reactor support building. An array of cold neutron guides fans out into a large guide hall, housing about 30 neutron research stations. Office, laboratory, and shop facilities are included to provide a complete users facility. The ANS is scheduled to begin operation at the Oak Ridge National Laboratory at the end of the decade. This Plant Design Requirements document defines the plant-level requirements for the design, construction, and operation of the ANS. This document also defines and provides input to the individual System Design Description (SDD) documents. Together, this Plant Design Requirements document and the set of SDD documents will define and control the baseline configuration of the ANS.

Surfaces have several unique properties that remain unexplained on the atomic level. These include (1) the unique chemical activity of rough surfaces, (2) the breaking of chemical bonds in narrow temperature ranges; and (3) the role of co-adsorption and strongly adsorbed monolayers during catalysis and tribological change (friction, lubrication). The dynamic surface restructuring model and surface structure induced variations in local density of states that have been suggested to rationalize the surface behavior await experimental confirmation. 24 refs., 10 figs., 2 tabs.

The Electronics Group in the Physics Department at Fermilab has designed and has had produced 20 prototypes of a full custom four channel time to voltage converter using the ES2 direct write 2 {mu}m CMOS process. The actual implementation of the design was performed under contract by ASIC designs Inc. of Naperville, Illinois. Each channel has two hit capability and one level of input buffering: that is, up to four voltages representing time internals can be stored from each input for later ADC conversion. The chip produces an edited list of hits and presents the appropriate analog value on its output for each digital value on its hit address lines. The next hit address and analog voltage in the event is presented in response to an external strobe. One current sum proportional to the number of inputs hit for each input buffer is also provided. The chip has been designed to be used on a fastbus TDC card developed here, but it is our belief that it could be adapted to many TDC applications. 2 refs., 8 figs.

The objective of the semiannual progress report is to summarize the technical results obtained during the latest reporting period. The information presented herein will include evaluated test data, design evaluations, the results of analyses and the significance of results. The program objective is to demonstrate the technology readiness of a TFE suitable for use as the basic element in a thermionic reactor with electric power output in the 0.5 to 5.0 MW(e) range, and a full-power life of 7 years. The TFE Verification Program builds directly on the technology and data base developed in the 1960s and early 1970s in an AEC/NASA program, and in the SP-100 program conducted in 1983, 1984 and 1985. In the SP-100 program, the attractive features of thermionic power conversion technology were recognized but concern was expressed over the lack of fast reactor irradiation data. The TFE Verification Program addresses this concern. 6 refs., 67 figs., 37 tabs.

The overall objective of this project is to sue molecular genetics to develop strains of bacteria with enhanced ability to remove sulfur from coal and to obtain data that will allow the performance and economics of a coal biodesulfurization process to be predicted. The work planned for the current quarter (May 1990 to July 1990) includes the following activities: (1) Construct a cloning vector that can be used in Rhodococcus rhodochrous IGTS8 from the small cryptic plasmid found in Rhodococcus rhodochrous ATCC 190607; (2) Develop techniques for the genetic analysis of IGTS8; (3) Continue biochemical experiments, particularly those that may allow the identification of desulfurization-related enzymes; (4) Continue experiments with coal to determine the kinetics of organic sulfur removal.

Under USDOE sponsorship, a project team consisting of the Institute of Gas Technology (IGT), Peabody Holding Company, Inc., and Bechtel Group is developing a process for the mild gasification of coal in a 100-pound/hour capacity isothermal process research unit (PRU) at IGT in Chicago. The IGT process is capable of converting bituminous coals to value-added co-products that can open new markets for the US coal industry. The conceptual IGT mild gasification process incorporates an integrated fluidized-/entrained-bed reactor supplying heat indirectly by a combination of char and gas recycle. The use of mild operating conditions (1000{degree} to 1300{degree}F), low pressures (<50 psig), and continuous operation in closed reactors, combined with the sale of value-added co-products, offer an environmentally sound and economical approach to advanced coal utilization. The PRU consists of an 8-inch-ID {times} 8-foot-long fluidized-bed reactor closely coupled to a 4-inch-ID {times} 13-foot-long entrained-bed reactor. The PRU test results have demonstrated process performance, including the effect of coal type and temperature on mild gasification co-product yields and their properties. The fates of the heteroatoms have also been analyzed. 9 refs., 16 figs., 41 tabs.

The Insolation Data Manual presents monthly averaged data which describes the availability of solar radiation at 248 National Weather Service (NWS) stations, principally in the United States. Monthly and annual average daily insolation and temperature values have been computed from a base of 24--25 years of data, generally from 1952--1975, and listed for each location. Insolation values represent monthly average daily totals of global radiation on a horizontal surface and are depicted using the three units of measurement: kJ/m{sup 2} per day, Btu/ft{sup 2} per day and langleys per day. Average daily maximum, minimum and monthly temperatures are provided for most locations in both Celsius and Fahrenheit. Heating and cooling degree-days were computed relative to a base of 18.3 C (65 F). For each station, global {bar K}{sub T} (cloudiness index) values were calculated on a monthly and annual basis. Global {bar K}{sub T} is an index of cloudiness and indicates fractional transmittance of horizontal radiation, from the top of the atmosphere to the earth's surface. The second section of this volume presents long-term monthly and annual averages of direct normal solar radiation for 235 NWS stations, including a discussion of the basic derivation process. This effort is in response …

The subject of {gamma}{prime} precipitation in a Ni-12.5 at. % Si alloy has been studied by modern diffraction and scattering techniques in the small-angle and large angle regimes, and by transmission electron microscopy. Special attention is placed upon the mechanism and kinetic evolution of {gamma}{prime} precipitates as a function of ageing conditions. Methods are shown for the determination of interdiffusion coefficient, the interfacial energy and the coherent solubility. The strain effect, due to lattice mismatch, on the spatial correlation and preferred alignment of precipitates is addressed. Scaling law for the particle growth has been tested against the current theories. Results obtained from the three mutually beneficial techniques are shown to be consistent, thereby allowing an integral view of the phase separation process in this system. 29 refs., 19 figs., 3 tabs.

The United States has long been accused of being energy inefficient based on a comparison of energy intensities among the industrialized countries. Energy intensity is commonly measured by computing the ratio of energy use per unit of Gross Domestic Product (GDP). This is not a true measure of efficiency, however, because it does not account for differences in the standard of living, differences in population densities, or other factors. After corrections are made to account for these factors, the United States often appears to be as efficient or more efficient than many of the other industrialized countries. In this analysis the industrialized economies considered are the Group of Seven (G7): the United States, Canada, Japan, France, Italy, West Germany, and the United Kingdom. In summary, since 1970 the United States has improved the efficiency of energy use as much or more than have the other G-7 countries. Frequently, the United States is more efficient in its use of energy than are other G-7 countries. Many of the differences in energy use result from the fact that the United States has the comparative advantage of abundant indigenous energy supplies which have been used to develop large energy intensive but not necessarily …

This report discusses the monthly progress of the Power Burst Facility/Boron Neutron Capture Therapy (PBF/BNLT) program for cancer treatment. Highlights of the PBF/BNCT Program during July 1990 include progress within the areas of: Gross boron analysis in tissue, blood, and urine; noninvasive boron quantitative determination; analytical radiation transport and interaction modeling for BNCT; large animal model studies; neutron source and facility preparation; administration and common support and PBF operations.

For a long time, earth scientists have qualitatively recognized that mineral assemblages in soils and rocks conform to established principles of chemistry. In the early 1960's geochemists began systematizing this knowledge by developing quantitative thermodynamic models based on equilibrium considerations. These models have since been coupled with advective-dispersive-diffusive transport models, already developed by ground-water hydrologists. Spurred by a need for handling difficult environmental issues related to ground-water contamination, these models are being improved, refined and applied to realistic problems of interest. There is little doubt that these models will play an important role in solving important problems of engineering as well as science over the coming years. Even as these models are being used practically, there is scope for their improvement and many challenges lie ahead. In addition to improving the conceptual basis of the governing equations, much remains to be done to incorporate kinetic processes and biological mediation into extant chemical equilibrium models. Much also remains to be learned about the limits to which model predictability can be reasonably taken. The purpose of this paper is to broadly assess the current status of knowledge in modeling reactive chemical transport and to identify the challenges that lie ahead.

This past year we have undertaken experiments at the University of Rochester's Laboratory for Laser Energetics investigating layer mixing and expansion velocities of spherical targets uniformly irradiated by high intensity laser light. We performed high resolution spectroscopic measurements of spherical plasmas, produced using the Omega laser, and have observed enhanced broadening of XUV emission lines due to the expansion velocities.

Any measured or assessed quantity contains uncertainty. The quantitative estimation of such uncertainty is becoming increasingly important, especially in assuring that safety requirements are met in design, regulation, and operation of nuclear installations. The CEC/USDOE Workshop on Uncertainty Analysis, held in Santa Fe, New Mexico, on November 13 through 16, 1989, was organized jointly by the Commission of European Communities (CEC's) Radiation Protection Research program, dealing with uncertainties throughout the field of consequence assessment, and DOE's Atmospheric Studies in Complex Terrain (ASCOT) program, concerned with the particular uncertainties in time and space variant transport and dispersion. The workshop brought together US and European scientists who have been developing or applying uncertainty analysis methodologies, conducted in a variety of contexts, often with incomplete knowledge of the work of others in this area. Thus, it was timely to exchange views and experience, identify limitations of approaches to uncertainty and possible improvements, and enhance the interface between developers and users of uncertainty analysis methods. Furthermore, the workshop considered the extent to which consistent, rigorous methods could be used in various applications within consequence assessment. 3 refs.

The main objectives of this research were to determine the optimum pyrolysis temperature for Sunnyside tar sand and to verify the operability and efficiency of the ROPE process at steady-state conditions for production of feedstock materials. The experiments were conducted in the 2-inch screw pyrolysis reactor (SPR). Four 24-hour tests and one 105-hour test were performed in the 2-inch SPR using Sunnyside tar sand. The 24-hour tests were designed to predict the optimum pyrolysis temperature for oil yield. The 105-hour test was conducted to confirm the optimum pyrolysis temperature with sufficient operating time to reach steady-state conditions with respect to product compositions. The following conclusions can be drawn from the Sunnyside tar sand 2-inch SPR tests: (1) Sunnyside tar sand can be processed without any major operational difficulty by the ROPE process. (2) Oil yields greater than Fischer assay were obtained during the 2-inch SPR tests. Oil yield greater than 80 wt % of the bitumen was obtained from the 105-hr test. (3) The ratio of heavy oil to light product oil is strongly dependent upon the pyrolysis temperature and increases with a decrease in the reaction temperature. The gas yield increases with the increase in pyrolysis temperature but the …

This report briefly discusses the following topics: rare and forbidden eta meson and muon decays to test the standard model; tests of charge symmetry and isospin invariance; studies of baryon resonances; and exploratory investigations in support of the previous programs. (LSP)

In 1986 the Hawaii Natural Energy Institute (HNEI) and the Florida Solar Energy Center (FSEC) were contracted by the Solar Energy Research Institute (SERI) to conduct an assessment of hydrogen production technologies and economic feasibilities of the production and use of hydrogen from renewable resources. In the 1989/90 period all monies were directed toward research and development with an emphasis on integration of tasks, focusing on two important issues, production and storage. The current year's efforts consisted of four tasks, one task containing three subtasks: Hydrogen Production by Gasification of Glucose and Wet Biomass in Supercritical Water; Photoelectrochemical Production of Hydrogen; Photoemission and Photoluminescence Studies of Catalyzed Photoelectrode Surfaces for Hydrogen Production; Solar Energy Chemical Conversion by Means of Photoelectrochemical (PEC) Methods Using Coated Silicon Electrodes; Assessment of Impedance Spectroscopy Methods for Evaluation of Semiconductor-Electrolyte Interfaces; Solar Energy Conversion with Cyanobacteria; Nonclassical Polyhydride Metal Complexes as Hydrogen Storage Materials. 61 refs., 22 figs., 11 tabs.

The program objective is to demonstrate efficient removal of fine particulates to sufficiently low levels to meet proposed small scale coal combustor emission standards using a cleanup technology appropriate to small scale coal combustors. This to be accomplished using a novel particulate removal device, the Confined Vortex Scrubber (CVS), which consists of a cylindrical vortex chamber with tangential flue gas inlets. The clean gas exit is via vortex finder outlets, one at either end of the tube. Liquid is introduced into the chamber and is confined within the vortex chamber by the centrifugal force generated by the gas flow itself. This confined liquid forms a layer through which the flue gas is then forced to bubble, producing a strong gas/liquid interaction, high inertial separation forces and efficient particulate cleanup. During this quarter a comprehensive series of cleanup experiments have been made for three CVS configurations. The first CVS configuration tested gave very efficient fine particulate removal at the design air mass flow rate (1 MM BUT/hr combustor exhaust flow), but had over 20{double prime}WC pressure drop. The first CVS configuration was then re-designed to produce the same very efficient particulate collection performance at a lower pressure drop. The current CVS …

The objective of the Solar/METC program is to prove the technical, economic, and environmental feasibility of coal-fired gas turbine for cogeneration applications through tests of a Centaur Type H engine system operated on coal fuel throughout the engine design operating range. This quarter, work was centered on design, fabrication, and testing of the combustor, cleanup, fuel specifications, and hot end simulation rig. 2 refs., 59 figs., 29 tabs.

The objective of the Duct Injection Technology Prototype Development Project is to develop a sound design basis for applying duct injection technology as a post-combustion SO{sub 2}emissions control method to existing coal-fired power plants. The necessary engineering design and scale-up criteria will be developed for the commercialization of duct injection technology for the control of SO{sub 2} emissions from coal-fired boilers in the utility industry. The primary focus of the analyses summarized in this Topical Report is the review of the known technical and economic information associated with duct injection technology. (VC)

Alloys from the aluminum-lithium-scandium-magnesium system have been cast and rolled for study. The goal is to evaluate this system for the development of superplastically formable, high strength alloys. Aluminum-scandium-magnesium alloys have shown potential as superplastic alloys. These alloys rely on small Al{sub 3}Sc (ordered L1{sub 2}) precipitates for grain structure stabilization and strengthening. Additional precipitation strengthening is required to raise their strength to levels sufficient for aircraft applications. The addition of lithium provides this additional strengthening through the formation of Al{sub 3}Li({delta}{prime}). To produce the alloys studied in this research, a unique induction melting furnace was constructed that incorporates special features to produce aluminum-lithium alloys with low hydrogen content. The furnace also features a water cooled, copper casting mold to achieve a moderately rapid solidification rate. This is because the amount of scandium used (0.5 wt %) is in excess of the solubility limit and Al{sub 3}Sc cannot be re-solutionized to any extent. It is therefore desired to super-saturate the matrix with as much scandium as possible for later precipitation. Two high lithium alloys were produced, ALS2 (nominal composition Al-2.2Li-O.5 Sc) and AlS4 (nominal composition Al-2.0Li-2.2Mg-0.5Sc) that were strengthened with {delta}{prime} (Al{sub 3}Li). These alloys exhibited strength and ductility superior …

Vanadium-base alloys are candidates for use as structural material in magnetic fusion reactors. In comparison to other candidate structural materials (e.g., Type 316 stainless and HT-9 ferritic steels), vanadium-base alloys such as V-15Cr-5Ti and V-20Ti have intrinsically lower long-term neutron activation, neutron irradiation after-heat, biological hazard potential, and neutron-induced helium and hydrogen transmutation rates. Moreover, vanadium-base alloys can withstand a higher surface-heat, flux than steels because of their lower thermal stress factor. In addition to having these favorable neutronic and physical properties, a candidate alloy for use as structural material in a fusion reactor must have dimensional stability, i.e., swelling resistance, and resistance to embrittlement during the reactor lifetime at a level of structural strength commensurate with the reactor operating temperature and structural loads. In this paper, we present experimental results on the swelling and tensile properties of several vanadium-base alloys after irradiation at 420, 520, and 600{degree}C to neutron fluences ranging from 0.3 to 1.9 {times} 10{sup 27} neutrons/m{sup 2} (17 to 114 atom displacements per atom (dpa)).