The details of a shingle module design which produces in excess of 97 watts/m/sup 2/ of module area at 1 kW/m/sup 2/ insolation and at 60/sup 0/C are reported. This selected design employs a tempered glass coverplate to provide the primary solar cell structural support. The use of the B.F. Goodrich FLEXSEAL roofing system as the outer skin of the shingle substrate provides a high confidence of achieving the 15 year service life goal. The fabrication and testing of a preproduction module of this design has demonstrated that this selected approach will meet the environmental testing requirements imposed by the contract. Attempts to fabricate a preproduction module of an alternative design, which embeds the solar cell assembly within a methyl methacrylate casting, proved unsuccessful.

The reaction of laser excited Ba*(/sup 3/D) states with nitric oxide is presented. BaO product is not detected, although the channel is thermodynamically open, and instead chemiluminescence is observed. Experiments which suggest that radiative recombination, Ba + NO ..-->.. BaNO* ..-->.. BaNO, is the observed reaction channel will also be presented.

Expanded development of total-flow expander technology in order to obtain efficient energy extraction from the liquid flow component of the geothermal well flow, in addition to steam enthalpy conversion, has been undertaken by the University of California, Lawrence Livermore Laboratory (LLL). The flow conditions necessary for this type of complete system performance characterization are beyond the capabilities of the test facility utilized in the preliminary tests at the LLL hot-water test facility. As an alternative to increasing the existing facility to meet the expanded test requirements, test facilities in the industrial California community are being surveyed to assess their capability in supporting future tests of the LLL expander. Biphase Engines, Inc. of Santa Monica, California was contracted by LLL to perform this survey. The goal of the Biphase Engines survey is to identify organizations with, first, an interest in supporting the LLL turbine test program and, second, to review their test capabilities with respect to the turbine test requirements. The results of the survey are described in the following sections which includes a listing of all organizations contacted. The responses to all inquiries are given. The affirmative responses to the test-support requirement are detailed with a description of the test …

The conceptual design of a solar process steam system began with studies and evaluations of various alternative design configurations. From these evaluations a final candidate design configuration was selected which is to be used for further detailed analysis and engineering. An evaluation of various types of distributed collector systems is presented. Cost-effectiveness of various distributed collectors was determined on the basis of total relative cost (including foundation and installation) of the collector per square foot of collector surface for the same thermal output at noon. The considerations used to select the optimum site also are given. System optimization studies are presented, including a discussion of whether a storage facility should be provided. It was found that none is required. Three alternate system configurations are described, optimized, and compared and a final concept is selected in which water is partially boiled in the slat type collectors and steam is separated in a steam drum. A cost-effectiveness criterion based on the unit cost of net annual thermal energy generated was used in the optimization studies and is discussed. The impact of the system on the environment is assessed and a preliminary safety analysis is presented. (LEW)

The Cool Pool is a variation of the evaporating roof pond idea. The pool is isolated from the living space and the cooled pond water thermosiphons into the water columns located within the building. A computer model of the Cool Pool and the various heat and mass transfer mechanisms involved in the system are discussed. Theory will be compared to experimental data collected from a Cool Pool test building.

In this paper we report on large scale multi-physics simulation of beam dynamics in electron linacs for next generation free electron lasers (FELs). We describe key features of a parallel macroparticle simulation code including three-dimensional (3D) space-charge effects, short-range structure wake fields, longitudinal coherent synchrotron radiation (CSR) wake fields, and treatment of radiofrequency (RF) accelerating cavities using maps obtained from axial field profiles. A macroparticle up-sampling scheme is described that reduces the shot noise from an initial distribution with a smaller number of macroparticles while maintaining the global properties of the original distribution. We present a study of the microbunching instability which is a critical issue for future FELs due to its impact on beam quality at the end of the linac. Using parameters of a planned FEL linac at Lawrence Berkeley National Laboratory (LBNL), we show that a large number of macroparticles (beyond 100 million) is needed to control numerical shot noise that drives the microbunching instability. We also explore the effect of the longitudinal grid on simulation results. We show that acceptable results are obtained with around 2048 longitudinal grid points, and we discuss this in view of the spectral growth rate predicted from linear theory. As an …

Unlike the classical Yersinia pestis strains, members of an atypical group of Y. pestis from Central Asia, denominated Y. pestis subspecies caucasica (also known as one of several pestoides types), are distinguished by a number of characteristics including their ability to ferment rhamnose and melibiose, their lacking the small plasmid encoding the plasminogen activator (pla) and pesticin, and their exceptionally large variants of the virulence plasmid pMT (encoding murine toxin and capsular antigen). We have obtained the entire genome sequence of Y. pestis Pestoides F, an isolate from the former Soviet Union that has enabled us to carryout a comprehensive genome-wide comparison of this organism's genomic content against the six published sequences of Y. pestis and their Y. pseudotuberculosis ancestor. Based on classical glycerol fermentation (+ve) and nitrate reduction (+ve) Y. pestis Pestoides F is an isolate that belongs to the biovar antiqua. This strain is unusual in other characteristics such as the fact that it carries a non-consensus V antigen (lcrV) sequence, and that unlike other Pla{sup -} strains, Pestoides F retains virulence by the parenteral and aerosol routes. The chromosome of Pestoides F is 4,517,345 bp in size comprising some 3,936 predicted coding sequences, while its pCD and …

Biogeochemical cycling of zinc is strongly influenced by sorption on birnessite minerals (layer-type MnO2), which are found in diverse terrestrial and aquatic environments. Zinc has been observed to form both tetrahedral (Zn{sup IV}) and octahedral (Zn{sup VI}) triple-corner-sharing surface complexes (TCS) at Mn(IV) vacancy sites in hexagonal birnessite. The octahedral complex is expected to be similar to that of Zn in the Mn oxide mineral, chalcophanite (ZnMn{sub 3}O{sub 7} {center_dot} 3H{sub 2}O), but the reason for the occurrence of the four-coordinate Zn surface species remains unclear. We address this issue computationally using spin-polarized Density Functional Theory (DFT) to examine the Zn{sub IV}-TCS and Zn{sup VI}-TCS species. Structural parameters obtained by DFT geometry optimization were in excellent agreement with available experimental data on Zn-birnessites. Total energy, magnetic moments, and electron-overlap populations obtained by DFT for isolated Zn{sup IV}-TCS revealed that this species is stable in birnessite without a need for Mn(III) substitution in the octahedral sheet and that it is more effective in reducing undersaturation of surface O at a Mn vacancy than is Zn{sub VI}-TCS. Comparison between geometry-optimized ZnMn{sub 3}O{sub 7} {center_dot} 3H{sub 2}O (chalcophanite) and the hypothetical monohydrate mineral, ZnMn{sub 3}O{sub 7} {center_dot} H{sub 2}O, which contains only tetrahedral …

Many complex systems can be represented and analyzed as networks, and examples that have benefited from this approach span the natural sciences. For instance, we now know that systems as disparate as the World-Wide Web, the Internet, scientific collaborations, food webs, protein interactions and metabolism all have common features in their organization, the most salient of which are their scale-free connectivity distributions and their small-world behavior. The recent availability of large scale datasets that span the proteome or metabolome of an organism have made it possible to elucidate some of the organizational principles and rules that govern their function, robustness and evolution. We expect that combining the currently separate layers of information from gene regulatory-, signal transduction-, protein interaction- and metabolic networks will dramatically enhance our understanding of cellular function and dynamics.

Transmission electron microscopy (TEM) was used to study pendeo-epitaxial GaN layers grown on polar and non-polar 4H SiC substrates. The structural quality of the overgrown layers was evaluated using a number of TEM methods. Growth of pendeo-epitaxial layers on polar substrates leads to better structural quality of the overgrown areas, however edge-on dislocations are found at the meeting fronts of two wings. Some misorientation between the 'seed' area and wing area was detected by Convergent Beam Electron Diffraction. Growth of pendeo-epitaxial layers on non-polar substrates is more difficult. Two wings on the opposite site of the seed area grow in two different polar directions with different growth rates. Most dislocations in a wing grown with Ga polarity are 10 times wider than wings grown with N-polarity making coalescence of these layers difficult. Most dislocations in a wing grown with Ga polarity bend in a direction parallel to the substrate, but some of them also propagate to the sample surface. Stacking faults formed on the c-plane and prismatic plane occasionally were found. Some misorientation between the wings and seed was detected using Large Angle Convergent Beam Diffraction.

High Level Waste (HLW) at the Savannah River Site (SRS) is stored in three forms: sludge, saltcake, and supernate. A small column ion-exchange (SCIX) process is being designed to treat dissolved saltcake waste before feeding it to the saltstone facility to be made into grout. The waste is caustic with high concentrations of various sodium salts and lower concentrations of radionuclides. Two cation exchange media being considered are a granular form of crystalline silicotitanate (CST) and a spherical form of resorcinol-formaldehyde (RF) resin. CST is an inorganic material highly selective for cesium that is not elutable. Through this process, radioactive cesium from the salt solution is absorbed into ion exchange media (either CST or RF) which is packed within a flow-through column. A packed column loaded with radioactive cesium generates significant heat from radiolytic decay. If engineering designs cannot handle this thermal load, hot spots may develop locally which could degrade the performance of the ion-exchange media. Performance degradation with regard to cesium removal has been observed between 50 and 80 C for CST [1] and at 65 C for RF resin [2]. In addition, the waste supernate solution will boil around 130 C. If the columns boiled dry, the …

This dissertation presents the measurement of the Cp-odd fraction and time-dependent CP violation parameters for the B{sup 0} {yields} D*{sup +} D*{sup -} decay. These results are based on the full BABAR dataset of (467 {+-} 5) x 10{sup 6} B{bar B} pairs collected at the PEP-II B Factory at the Stanford Linear Accelerator Center. An angular analysis finds that the CP-odd fraction of the B{sup 0} {yields} D*{sup +} D*{sup -} decay is R{sub {perpendicular}} = 0.158 {+-} 0.028 {+-} 0.006, where the first uncertainty is statistical, and the second is systematic. A fit to the flavor-tagged, time-dependent, angular decay rate yields C{sub +} = 0.02 {+-} 0.12 {+-} 0.02; C{sub {perpendicular}} = 0.41 {+-} 0.50 {+-} 0.08; S{sub +} = -0.76 {+-} 0.16 {+-} 0.04; S{sub {perpendicular}} = -1.81 {+-} 0.71 {+-} 0.16, for the CP-odd ({perpendicular}) and CP-even (+) contributions. Constraining these two contributions to be the same results in C = 0.047 {+-} 0.091 {+-} 0.019; S = -0.71 {+-} 0.16 {+-} 0.03. These measurements are consistent with the Standard Model and with measurements of sin2{beta} from B{sup 0} {yields} (c{bar c})K{sup 0} decays.

Remarkable scientific progress has been demonstrated toward the creation of a low cost (“printable”) solar cell technology by the interdisciplinary group at UC Santa Barbara. Multi-layer architectures were implemented with clean interfaces were demonstrated; the various interfaces are sharp; there is no evidence of inter-layer mixing. This is indeed remarkable since each of these layers was processed from solution. The use of “Processing Additives” such as the alkanedithiols was demonstrated to increase the power conversion efficiency of BHJ solar cells by a factor of two. Equally important, the mechanism by which these Processing Additives function has been identified.

The influence of pulsed 4 MeV Ni ion bombardment, with and without simultaneous helium injection, has been explored in a low swelling, Ti-modified austenitic stainless steel. Irradiations were carried out to 70 dpa at 950/sup 0/K; the pulsing frequencies were either 60 s on/off or 1 s on/off. Compared to continuous irradiation, pulsing caused a decrease in the interstitial loop diameter at 1 dpa, although at higher doses the overall dislocation density was not affected. Pulsing and helium both promoted the stability of MC precipitates and retarded the subsequent G phase formation; in some cases G-phase was suppressed and eta phase formed instead. Small bubble-like cavities were observed to grow into large voids after steady dual beam irradiation to 70 dpa. However, this conversion was suppressed by pulse irradiation to 70 dpa and furthermore the sizes of the small cavities were somewhat reduced. The results are explained in terms of current mechanistic understanding of mean point defect kinetics and the evolution of microstructure and microcomposition during irradiation with superimposed annealing periods.

This document presents our proposal to continue the activities of Boston University researchers in eight projects in high energy physics research: Colliding Beams Physics; Accelerator Design Physics; MACRO Project; Proton Decay Project; Theoretical Particle Physics; Muon G-2 Project; and Hadron Collider Physics. The scope of each of these projects is presented in detail in this paper.

This report addresses groundwater modeling performed to support the Environmental Impact Statement (EIS) that is being prepared by the Department of Energy (DOE). The EIS pertains to construction and operation of a new production reactor (NPR) that is under consideration for the Savannah River Site (SRS). Three primary issues are addressed by the modeling analysis: (1) groundwater availability, (2) changes in vertical hydraulic gradients as a result of groundwater pumpage, and (3) migration of potential contaminants from the NPR site. The modeling indicates that the maximum pumpage to be used, 1000 gpm, will induce only minor drawdown across SRS. Pumpage of this magnitude will have a limited effect on the upward gradient from the Cretaceous into the Tertiary near Upper Three Runs Creek. Potentiometric surface maps generated from modeled results indicate that horizontal flow in the water table is either towards Four Mile Creek to the north or to Pen Branch on the south. Particle tracking analysis indicates that the primary flow paths are vertical into the Lower Tertiary Zone, with very little lateral migration. Total travel times from the NPR site to the edge of the model (approximately 3 miles) is on the order of 50 years. The flow …

The intent of this study is to determine the extent of delays experienced in planning and constructing transmission lines in the continental United States. The reasons for the delays are identified for each line studied and their effect on the total electrical system is sought. Data was collected for 136 different lines either recently built or currently under study. Statistics were developed for each line in several categories and comparisons of lines delayed were made by company, area served and generation capacity. From the study presented here it was found that: right-of-way acquisition procedures including condemnation and easement negotiation practices delay more projects than local, state and federal regulatory requirements combined; load growth reductions particularly in the east have reduced the impact of regulatory delays; the south, southeast and southwestern areas of the country experience fewer delays in constructing transmission lines than the more populated states, and the cost for corridor delays was responded to for only 17 of the 142 projects surveyed. By far the most costly delay is the expense of condemning land for transmission right-of-way.

The objective of this research is to investigate the technical feasibility of producing solar-cell-quality sheet silicon to meet the DOE 1986 cost goal of 70 cents/watt. The silicon-on-ceramic approach is to coat a low-cost ceramic substrate with large-grain polycrystalline silicon by unidirectional solidification of molten silicon. Results are reported. A new silicon-coating system, SCIM-II, was designed and constructed. A design strategy to avoid buckling and breaking of substrates has been formulated, implemented, and verified. Detailed thermal modeling of the heating and cooling zones has been performed, and the results have been compared with experiment. A number of modifications have been made in SCIM-II to implement the strategy to minimize thermal stress and to improve reproducibility of coating conditions. Dip-coating has been continued in order to supply material for cell fabrication, since impure carbon parts have been used in the SCIM-coater while changes were still being made. The best cell had a total-area efficiency of 10.5% (AM1, AR) for a cell area of 5 cm/sup 2/. The highest efficiencies were produced with a PH/sub 3/ diffusion at 850/sup 0/C, followed by a slow cooldown at about 5/sup 0/C/min. Theoretical modeling of SOC solar cells shows that present cell performance is limited …

In order to better understand the process of slurry atomization, it is important to observe the influence of fluid non-Newtonian rheological behavior on the spray formation process. As a first step, glycerin-water solutions have been atomized. This report describes findings of photographs taken during atomization. 19 figs.

An important loss process in CTR plasmas is the process of dielectronic recombination, which proceeds via autoionizing states. At this date, however, this problem is not fully understood, largely because of the nearly complete lack of fundamental atomic data on high excited autoionizing states. In this document, we outline the continuation of a program to investigate the properties of autoionizing states of alkaline earth metals by means of a novel laser excitation technique developed at SRI. This approach will allow us to study, for the first time, autoionizing states of arbitrary n, and l in a controlled environment. Specifically, we plan to measure autoionization rates and branching ratios as a function of n and l and the effects of electric fields. These experiments should yield the basic atomic data, autoionization rates, required as inputs to sophisticated model calculations of dielectronic recombination rates.

Energy-dispersive x-ray fluorescence analysis can be used for quantitative on-line monitoring of the product concentrations in single- or dual-element process streams in a reprocessing plant. The 122-keV gamma ray from /sup 57/Co is used to excite the K x-rays of uranium and/or plutonium in nitric acid solution streams. A collimated HPGe detector is used to measure the excited x-ray intensities. Net solution radioactivity may be measured by eclipsing the exciting radiation, or by measuring it simultaneously with a second detector. The technique is nondestructive and noninvasive, and is easily adapted directly to pipes containing the solution of interest. The dynamic range of the technique extends from below 1 to 500 g/l. Measurement times depend on concentration, but better than 1% counting statistics can be obtained in 100 s for 400 g/l concentrations, and in 1000 s for as little as 10 g/l. Calibration accuracies of 0.3% or better over the entire dynamic range can be achieved easily using carefully prepared standards. Computer-based analysis equipment allows concentration changes in flowing streams to be dynamically monitored. Changes in acid normality of the stream will affect the concentration determined, hence it must also be determined by measuring the intensity of a transmitted /sup …

Gamma-ray spectroscopy measurements have been made on mixed uranium and plutonium oxides in sealed containers to determine the uranium and plutonium enrichment and isotopics. Experimental results obtained using two different methods were in good agreement with the known contents. The first method is applicable to thick samples of freshly reprocessed mixed oxide and determines isotopic abundances from measured absolute gamma-ray intensities. Measurement times depend on plutonium enrichment, but for mixed oxide enriched to 12% in plutonium, the fissionable content can be determined to better than 0.5% in 2 h. The second approach utilizes intensity ratios of selected pairs of gamma-rays to determine plutonium enrichment and uranium and plutonium isotopes. This method requires at least 12 h to determine the plutonium enrichment to an accuracy of 0.5%. However, it cannot be applied until the /sup 238/U daughter activities in the mixed oxide reach equilibrium, which requires at least 5 months after separation. Preliminary conclusions drawn from these two noninvasive and nondestructive measurement techniques, and recommendations for future experiments are discussed.

The utility of optical emissions for diagnostic purposes in the ion-focused regime is explored. Two possible uses of the emissions are examined: (1) the time delay of 337.1-nm emissions relative to 391.4-nm emissions is observed to scale with the beam-neutralization time, and (2) emissions at 391.4 nm may determine beam-current density at the front of the beam.

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