A sixteen channel analog transient recorder with 256 cells per channel has been fabricated as an integrated circuit. The circuit uses switched capacitor array technology to achieve simultaneous read/write capability and twelve bit dynamic range. Combined with highly parallel analog-to-digital converter and readout control circuitry being developed this system should satisfy the demanding electronics requirements for calorimeter detectors at the SSC. The system design and test results are presented.

Multisphere spectrometers have been used widely to determine neutron spectra and other related quantities from various radiation sources. At Lawrence Berkeley Laboratory (LBL), the multisphere spectrometer has taken measurements at different LBL accelerator facilities (the SuperHILAC, the BEVALAC, and the 88{double prime}-Cyclotron) as well as for measurements in the tunnel of the Tevatron at Fermilab. Spectra were unfolded with a LOUHI code using Sanna's response function, which gave satisfactory results. The neutron-scattering effect is important for the Bonner detectors, which will be discussed briefly. 9 refs.

We discuss positron annihilation (2D-ACAR) measurements in the C- projection on an untwinned metallic single crystal of YBa{sub 2}Cu{sub 3}O{sub 7-x} as a function of temperature, for five temperatures ranging from 30K to 300K. The measured 2D-ACAR intensities are interpreted in terms of the electron-positron momentum density obtained within the KKR-band theory framework. The temperature dependence of the 2D-ACAR spectra is used to extract a background corrected'' experimental spectrum which is in remarkable accord with the corresponding band theory predictions, and displays in particular clear signatures of the electron ridge Fermi surface.

Subsurface systems containing radionuclide, heavy metal, and organic wastes must be carefully attended to avoid further impacts to the environment or exposures to human populations. It is appropriate, therefore, to invest in basic research to develop the requisite tools and methods for addressing complex cleanup problems. The rational modification of subsurface microoganisms by enzyme recruitment and enzyme design, in concert with engineered systems for delivery of microorganisms and nutrients to the contaminated zone, are potentially useful tools in the spectrum of approaches that will be required for successful remediation of deep subsurface contamination.

Stars of a cluster surrounding the central black hole in an AGN will collide with the accretion disk. For a central black hole of 10{sup 8} M{circle dot} and a cluster with 10{sup 7} {minus} 10{sup 8} stars within a parsec, one estimates that {approximately}10{sup 4} such collisions will occur per year. Collisions are hypersonic (Mach number M {much gt} 1). Some of the wake of the star -- the disk material shocked by its passage -- will follow it out of the disk. Such star tails'' with the estimated masses {delta}m {approximately} 10{sup 25} {minus} 10{sup 27} g subsequently expand, cool and begin to recombine. We propose that -- when illuminated by the ionizing flux from the central source -- they are likely to be the origin of the observed broad emission lines.

An aqueous route to the deposition of complex metal oxide films is based upton the complexation of the corresponding metal nitrate salts by glycine, followed by spin-casting the concentrated solution onto silica substrates. The presence of glycine serves to frustrate precipitation and leads to the formation of a glassy matrix through which metal cations are homogeneously dispersed. Subsequent heating of coated substrates initiates an oxidation-reduction reaction which removes the organic matrix and residual nitrate leaving behind a film of the desired oxide composition. Using this method, ruby (Cr:Al{sub 2}O{sub 3}) and Sm:YAG (Sm:Y{sub 3}Al{sub 5}O{sub 12}) films on the order of 150 nm thick have been deposited. The respective phase have been confirmed by XRD data and from the measured fluorescence spectra. The red fluorescence exhibited by these materials under 488 nm excitation is dependent upon the ambient temperature and pressure. A marked shift in wavelength is observed as a function of increasing pressure. Ruby also exhibits a temperature dependent wavelength shift in contrast to Sm:YAG where a negligible shift is seen to temperatures near 1200 K. Fluorescence lifetimes of both materials exhibit a temperature dependence which varies with dopant concentration. This work suggests the possible application of these films …

Accurately predicting wind turbine blade loads and response is important for the proper design of wind turbines. The need to accurately predict both deterministic and stochastic blade loads is now widely recognized. Previous rotor code development and validation efforts at NREL have concentrated on prediction of deterministic and stochastic blade loads for rigid hub rotors. During the past year this effort was expanded for predicting blade and shaft loads for two-bladed teetering hub rotors. The NREL (formerly SERI) Teetering Rotor Analysis Program (STRAP), a derivative of the Force and Loads Analysis Program (FLAP), can include the effects of rotor undersling, delta-3 and the effects of a concentrated hub mass. The degrees of freedom include rotor teeter and symmetric and asymmetric rotor flap modes. A time-dependent, prescribed yaw motion can also be input to the code. Loads due to turbulent wind inputs are also calculated. In this paper, final code modifications, final comparisons of load predictions to test data, and finally, the direction for new code development activities at NREL will be described. 12 refs.

A general purpose relativistic cascade code ARC has been developed to study ion-ion collisions. As a first application of ARC we study Si+Au collisions at 14.6 GeV/c using two hadronic models which use the same two-body data as input, but with different assumptions about the way particles are produced. Comparison with data from experiment E802 suggests the importance of barvonic resonances in nucleus-nucleus collisions at BNL-AGS energies.

A cluster expansion is used to predict the fcc ground states, i.e., the stable phases at zero Kelvin as a function of composition, for alloy systems. The intermetallic structures are not assumed, but derived regorously by minimizing the configurational energy subject to linear constraints. This ground state search includes pair and multiplet interactions which spatially extend to fourth nearest neighbor. A large number of these concentration-independent interactions are computed by the method of direct configurational averaging using a linearized-muffin-tin orbital Hamiltonian cast into tight binding form (TB-LMTO). The interactions, derived without the use of any adjustable or experimentally obtained parameters, are compared to those calculated via the generalized perturbation method extention of the coherent potential approximation within the context of a KKR Hamiltonian (KKR-CPA-GPM). Agreement with the KKR-CPA-GPM results is quite excellent, as is the comparison of the ground state results with the fcc-based portions of the experimentally-determined phase diagrams under consideration.

The Photovoltaic Manufacturing Technology (PVMaT) project is a government/industry photovoltaic manufacturing research and development (R D) project composed of partnerships between the federal government (through the US Department of Energy) and members of the US photovoltaic (PV) industry. It is designed to assist the US PV industry in improving manufacturing processes, accelerating manufacturing cost reductions for PV modules, increasing commercial product performance, and generally laying the groundwork for a substantial scale-up of US-based PV manufacturing plant capabilities. The project is being carried out in three separate phases, each focused on a specific approach to solving the problems identified by the industrial participants. These participants are selected through competitive procurements. Furthermore, the PVMaT project has been specifically structured to ensure that these PV manufacturing R D subcontract awards are selected with no intention of either directing funding toward specific PV technologies (e.g., amorphous silicon, polycrystalline thin films, etc.), or spreading the awards among a number of technologies (e.g., one subcontract in each area). Each associated subcontract under any phase of this project is, and will continue to be, selected for funding on its own technical and cost merits. Phase 1, the problem identification phase, was completed early in 1991. Phase 2 …

A queuing theory model was used in the initial design of the D0 data acquisition system. It was mainly used for the front end electronic systems. Since then the model has been extended to include the entire data path for the tracking system. The tracking system generates the most data so we expect this system to determine the overall transfer rate. The model was developed using both analytical and simulation methods for solving a series of single server queues. We describe the model and the methods used to develop it. We also present results from the original models, updated calculations representing the system as built and comparisons with measurements made with the hardware in place for the cosmic ray test run. 3 refs.

We present results of magnetization and pressure measurements on recently discovered superconductors K{sub 3}C{sub 60} and Rb{sub 3}C{sub 60}, as well as ferromagnetic C{sub 60} TDAE, and discuss the nature of the ground state suggested by these studies.

This paper presents the results of an investigation to determine the feasibility of a novel approach to measuring gas flow in a pipe. An optical fiber is stretched across a pipe and serves as a sensor which is based upon the well-established principle of vortex shedding of a cylinder in cross-flow. The resulting time varying optical signal produces a frequency component proportional to the average velocity in the pipe which is in turn proportional to volumetric flow. A Mach-Zehnder interferometer is used to enhance the accuracy of the vortex shedding frequency signal. The analytical and experimental effort discussed herein shows that the concept is feasible and holds promise for a sensitive and accurate flow measuring technique.

The current knowledge is reviewed on (1) the effects of neutron irradiation on tensile strength and ductility, ductile-brittle transition temperature, creep, fatigue, and swelling of vanadium-base alloys, (2) the compatibility of vanadium-base alloys with liquid lithium, water, and helium environments, and (3) the effects of hydrogen and helium on the physical and mechanical properties of vanadium alloys that are potential candidates for structural materials applications in fusion systems. Also, physical and mechanical properties issues are identified that have not been adequately investigated in order to qualify a vanadium-base alloy for the structural material in experimental fusion devices and/or in fusion reactors.

A procedure is described for depositing a conductive layer of gold on the exterior of a fused-silica capillary used in gas chromatography. By subjecting a section of the column near the inlet to a thermal cycle of cryogenic cooling and ohmic heating, volatile samples are concentrated and subsequently injected. The performance of this trap as a chromatographic injector is demonstrated. Several additional applications are suggested and the unique properties of this device are discussed. 11 refs., 5 figs., 1 tab.

The experimental status of the strange 1 {sup {minus}} mesons is briefly reviewed and compared with the non-strange sector and quark model expectations. The results described are taken from a 4.1 event/nb exposure of the LASS spectrometer to an 11 GeV/e K{sup {minus}} beam.

Solar process heat technology relates to solar thermal energy systems for industry, commerce, and government. Applications include water preheating and heating, steam generation, process hot air, ventilation air heating, and refrigeration. Solar process heat systems are available for commercial use. At the present time, however, they are economically viable only in niche markets. This paper describes a functioning system in one such market. The California Department of Corrections (CDOC), which operates correctional facilities for the state of California, uses a solar system for providing hot water and space heating at the California Correctional Institute at Tehachapi (CCI/Tehachapi). CCI/Tehachapi is a 5100-inmate facility. The CDOC does not own the solar system. Rather, it buys energy from private investors who own the solar system located on CCI/Tehachapi property; this arrangement is part of a long-term energy purchase agreement. United Solar Technologies (UST) of Olympia Washington is the system operator. The solar system, which began operating in the fall of 1990, utilizes 2677 m{sup 2} (28,800 ft{sup 2}) of parabolic through solar concentrators. Thermal energy collected by the system is used to generate hot water for showers, kitchen operations, and laundry functions. Thermal energy collected by the system is also used for space …

We have carried out 2D-ACAR measurements on an untwinned single crystal of YBa{sub 2}Cu{sub 3}O{sub 7-x} as a function of temperature, for five temperatures ranging from 30K to 300K. We show that these temperature dependent 2D-ACAR spectra can be described to a good approximation as a superposition of two temperature independent spectra with temperature dependent weighting factors. We show further how the data can be used to correct for the background'' in the experimental spectrum. Such a background corrected'' spectrum is in remarkable accord with the corresponding band theory predictions, and displays in particular clear signatures of the electron ridge Fermi surface.

Air exhibiting very low concentrations of light-scattering aerosol particles is occasionally observed even in industrialized regions. Evidence is presented that this very clean air results from highly efficient removal of aerosol particles coupled to the removal of water in precipitation.

Internal oxidation pretreatments of Co-15wt%Cr and Co-15wt%Cr-1wt%Ti were carried out using a Rhines pack in quartz, in mullite and in alumina. A dispersion of titanium oxide particles formed in the Ti-containing alloy as a result of the internal oxidation. However, silicon also diffused into all treated specimens when the pretreatments were carried out in quartz or in mullite. The effect of various pretreatments on the subsequent oxidation of these alloys was studied at 1000{degree}C, and compared with that of Co-15wt%Cr-1wt%Si alloy. The main purpose of this study was to determine the relative effectiveness of the dispersed oxide particles and the contaminated silicon on the selective oxidation of chromium. It was found that the oxidation behavior of both treated alloys were strongly affected by the degree of silicon contamination. Selective oxidation of chromium to form a nearly continuous protective Cr{sub 2}O{sub 3} scale was achieved with greater than 0.4wt% silicon. The presence of dispersed particles reduced initial oxidation rate, but was ineffective in promoting Cr{sub 2}O{sub 3} scale formation.

Two-dimensional fluid simulations of ITER double-null divertor scrape-off-layer plasma conditions have been restricted to examining a single outboard divertor plate with up/down symmetry assumed. The present work evaluates the effect of pumping at only one plate on particle flow patterns and other parameters of interest. Pumping only at one plate results in reduced sheath temperatures at both plates but an increased heat flux at the pumped plate. The physics assumptions for separatrix density (n{sub SEP}={l angle}n{r angle}/3.5) and for radial particle diffusivity (D=0.66m{sup 2}/s) used in the simulation of ITER edge plasma result in particle throughputs two orders of magnitude greater than that required for acceptable fusion-product ash removal rates. The particle confinement time, however, is an order of magnitude shorter than the transport energy confinement time, {tau}{sub E}. Plasmas (D=0.04m{sup 2}/s) which would have {tau}{sub p} {approximately} {tau}{sub E} are evaluated and found to have unacceptably high plasma temperatures and heat flux at the plate. Ash removal rates are still acceptable. A plasma recycle coefficient of R=0.965 reduces the particle throughput by a factor of 2.8 below the no-recycle case.

The United States Department of Energy (DOE) is facing a large task in completing Remedial Investigations and Feasibility Studies (RI/FS) for hazardous waste sites across the nation. One of the primary objectives of an RI/FS is the specification of viable sequences of technology treatment trains which can provide implementable site solutions. We present a methodology which integrates expert system technology within an object-oriented framework to create a cooperative reasoning system designed to provide a comprehensive list of these implementable solutions. The system accomplishes its goal of specifying technology trains by utilizing a team'' of expert system objects. The system distributes the problem solving among the individual expert objects, and then coordinates the combination of individual decisions into a joint solution. Each expert object possesses the knowledge of an expert in a particular technology. An expert object can examine the parameters and characteristics of the waste site, seek information and support from other expert objects, and then make decisions concerning its own applicability. This methodology has at least two primary benefits. First, the creation of multiple expert objects provides a more direct mapping from the actual process to a software system, making the system easier to build. Second, the distribution of …

Fatigue and environmentally assisted cracking of piping, pressure vessels, and core components in light water reactors (LWRs) are important concerns as extended reactor lifetimes are envisaged. The degradation processes include intergranular stress corrosion cracking (IGSCC) of austenitic stainless steel (SS) piping in boiling water reactors (BWRs), and propagation of fatigue or SCC cracks (which initiate in sensitized SS cladding) into low-alloy ferritic steels in BWR pressure vessels. Similar cracking has also occurred in upper shell-to-transition cone girth welds in pressurized water reactor (PWR) steam generator vessels. Another concern is failure of reactor-core internal components after accumulation of relatively high fluence, which has occurred in both BWRs and PWRs. Research during the past year focused on (1) fatigue and SCC of ferritic steels used in piping and in steam generator and reactor pressure vessels, (2) role of chromate and sulfate in simulated BWR water in SCC of sensitized Type 304 SS, and (3) irradiation-assisted SCC in high- and commercial-purity Type 304 SS specimens from control-blade absorber tubes used in two operating BWRs. Failure after accumulation of relatively high fluence has been attributed to radiation-induced segregation (RIS) of elements such as Si, P, Ni, and Cr. This document provides a summary of …

The Stanford Synchrotron Radiation Laboratory (SSRL) Injector is comprised of a linear accelerator (linac) capable of energies {le} 150 MeV, a 3 GeV booster synchrotron, and a beam line to transport the electrons into the storage ring SPEAR. The injector is shielded so that under normal operating conditions, the annual dose equivalent at the shield surface does not exceed 10 mSv. This paper describes the shielding and radiation protection at the injector.