Silicon-germanium alloys are used as thermoelectric materials for radioisotope thermoelectric generators. One problem is the loss of the alloy by sublimation. In the Unicouple, sublimation was minimized by a Si/sub 3/N/sub 4/ coating. In the Multicouple design the application of Si/sub 3/N/sub 4/ coatings which is done at high temperature is not practical. Suppression of sublimation in the Multicouple design is presently accomplished by applying glass coatings. The difficulties encountered with the glass coatings are associated with the poor adherence of the coatings. In the present study, commercial oxide points (mainly ZrO/sub 2/) which have low thermal expansion coefficients are used as coating materials. No spalling from the surface of the coated sample occurred in 1506 hours at 1080/sup 0/C in vacuum, and sublimation was reduced significantly. Zirconium silicate was observed on the surface by x-ray diffraction.

Future space missions envision the use of large nuclear reactors utilizing either a single or a two-phase alkali-metal working fluid. The design and analysis of such reactors require state-of-the-art computer codes that can properly treat alkali-metal flow and heat transfer in a reduced-gravity environment. New flow regime maps, models, and correlations are required if the codes are to be successfully applied to reduced-gravity flow and heat transfer. General plans are put forth for the reduced-gravity experiments which will have to be performed, at NASA facilities, with benign fluids. Data from the reduced-gravity experiments with innocuous fluids are to be combined with normal gravity data from two-phase alkali-metal experiments. Because these reduced-gravity experiments will be very basic, and will employ small test loops of simple geometry, a large measure of commonality exists between them and experiments planned by other organizations. It is recommended that a committee be formed, to coordinate all ongoing and planned reduced gravity flow experiments.

Results of recent beam tests of a physics prototype Cerenkov Ring Imaging Detector (CRID) for the SLD experiment at the SLAC Linear Collider (SLC) are presented. The system includes both liquid (C/sub 6/F/sub 14/) and gas (isobutane) radiators and an 80 cm long Time Projection Chamber (TPC) with a gaseous TMAE (Tetrakis-Dimethylamino-Ethylene) photocathode and charge division readout of proportional wires. Handling of TMAE and development of a gas delivery system are discussed. Design considerations for the construction of the TPC anode planes are presented. Measurements of the multiplicity of detected Cerenkov photons, of Cerenkov angles, and the resolution with both radiators are presented. The particle identification capability of this detector is discussed.

Pure Ni and dilute NiSi and NiGe alloys were irradiated at 6 K with either fast neutrons or 3 MeV electrons. The resulting defect structures were studied using diffuse x-ray scattering methods after different annealing treatments. For both types of irradiation of pure Ni, large interstitial and vacancy dislocation loops developed on annealing. In contrast, interstitial agglomerates in a NiSi/sub .01/ alloy contained no more than approx. =10 interstitials, and few vacancy loops were observed. Complete recovery was observed at lower temperatures in the alloy. Similar results were found for NiGe/sub .01/, although larger interstitial clusters were observed. The results are discussed within the model for the trapping reactions developed previously to explain the results of e/sup -/ irradiation of these same alloys.

The inclusive cross-secton for the production of the singly-strange baryons lambda and anti lambda, along with the differential cross-sections in momentum and energy, are measured by e/sup +/e/sup -/ annihilation at a center-of-mass energy of 29GeV. The charged decay mode lambda ..-->.. p..pi.. is used in a search for polarization. Such a polarization may be used as a check of CP invariance in lambda production. The sample of events with two detected decays is analyzed for correlations in production angle. 43 refs., 44 figs.

Orbifold compactifications provide a practical approach to string symmetry breaking. They have the potential to bridge the gap between string theory and the physics of the standard model. 7 refs., 5 figs.

This document describes radioisotope distribution from DOE facilities to private firms including foreign and other DOE facilities. The information is divided into five sections: (1) isotope suppliers, facility contacts, and isotopes or services supplied; (2) customers, suppliers, and isotopes purchased; (3) isotopes purchased cross-referenced with customer numbers; (4) geographic locations of radioisotope customers; and (5) radioisotope sales and transfer - FY 1985.

For biomass gasification to make a significant contribution to the energy picture in the next decade, emphasis must be placed on the generation of clean, pollutant-free gas products. This reports attempts to quantify levels of particulated, tars, oils, and various other pollutants generated by biomass gasifiers of all types. End uses for biomass gases and appropriate gas cleaning technologies are examined. Complete systems analysis is used to predit the performance of various gasifier/gas cleanup/end use combinations. Further research needs are identified. 128 refs., 20 figs., 19 tabs.

Recent developments in accelerator physics and technology have led to lower cost estimates for a heavy-ion induction linac driver. Studies show that the cost of electricity produced using such a driver are competitive with other fusion systems at a plant capacity of 1.2 GW/sub e/ and are competitive with projected fission power costs at less than 4 GW/sub e/.

A beam vacuum chamber was proposed to allow synchrotron light to radiate from a circulating electron beam into an antechamber containing photon targets, pumps, etc. To determine the impedance such a geometry would present to the beam, electromagnetic measurements were carried out on a section of chamber using for low frequencies a current-carrying wire and for up to 16 GHz, a resonance perturbation method. Because the response of such a chamber would depend on upstream and downstream restrictions of aperture yet to be determined, the resonance studies were analyzed in some generality. The favorable conclusion of these studies is that the antechamber makes practically no contribution to either the longitudinal or the transverse impedances.

Investigation of the volcanic tuff beds of Yucca Mountain Nevada, as a potential site for a high-level waste repository is a function of the Nevada Nuclear Waste Storage Investigations (NNWSI). A series of tests with SRL 165 type glass was performed to determine whether the NNWSI Unsaturated Test could be used to produce data that would be useful in assessing waste form performance under unsaturated conditions anticipated for the NNWSI repository site.

Throughout the domain of the H R diagram lie groupings of stars whose luminosity varies with time. These variable stars can be classified based on their observed properties into distinct types such as ..beta.. Cephei stars, delta Cephei stars, and Miras, as well as many other categories. The underlying mechanism for the variability is generally felt to be due to four different causes: geometric effects, rotation, eruptive processes, and pulsation. In this review the focus will be on pulsation variables and how the theory of stellar evolution can be used to explain how the various regions of variability on the H R diagram are populated. To this end a generalized discussion of the evolutionary behavior of a massive star, an intermediate mass star, and a low mass star will be presented. 19 refs., 1 fig., 1 tab.

A detailed description of charm decays has emerged. The various concepts involved are sketched. Although this description is quite successful in reproducing the data the chapter on heavy flavour decays is far from closed. Relevant questions like on th real strength of weak annihilation, Penguin operators, etc. are still unanswered. Important directions in future work, both on the experimental and theoretical side are identified.

We have performed exploratory tests to investigate the effects of extended exposure of tuffs from Yucca Mountain, Nevada, to temperatures and pressures similar to those that will be encountered in a high-level nuclear waste repository. In a preliminary report we described statistically significant changes in strength properties and generally minor changes in porosity and grain density. In the present report we describe additional measurements that indicate possible changes in permeability (in one tuff type) after exposure for 2 to 6 months at temperatures from 80 to 180 C, confining pressures of 9.7 and 19.7 MPa, and water pore pressures of 0.5 and 19.7 MPa. Mineralogic examinations have established reactions involving dissolution of silica and feldspar minerals and possible conversion of clinoptilolite to mordenite. We conclude that rock properties important to the operation of a nuclear waste repository in tuff are likely to change over time when exposed to simulated repository conditions, and the details of these time-dependent processes should be investigated further.

Some general improvements to the on-line mass separator RAMA have yielded a factor of five increase in yield for most elements. By placing the ion source region at the full accelerating potential of 20 kV, the effective skimmer-plasma distance has been reduced from 12 cm to <2 cm. Changes in the helium-jet chamber and large volume pumping arrangement necessitated by placing the ion source region at high voltage are also given. Finally, details for a new highly shielded detector station are presented.

The performance of a new capacitive flowmeter has been assessed experimentally in a gas-entrained solid flow stream at the Argonne National Laboratory (ANL) Solid/Gas Flow Test Facility (S/GFTF) for solid feedrates in the range of 0.5 to 2 kg/s and solid-gas loadings up to 22, corresponding to a range of solid volume fractions extending from 0.004 to 0.016. Two types of nonintrusive instruments using the capacitive principle were fabricated at ANL and installed in the horizontal leg of a 12.3 m test section to sense the solids. An improved electrode geometry designed to maximize the coverage of the duct interior while minimizing the readout error due to a nonuniform electric field, was incorporated for one spoolpiece with the sensing electrodes on the outside surface of a ceramic liner and for another spoolpiece with the sensing electrodes mounted flush with the duct inside surface. The capacitive instruments measured the solid volume fraction and the average particle velocity. The results are compared with time-of-flight measurements of short-lived radioactive particles that duplicate closely the size and density of the 1000..mu.. glass beads used in these flow tests. Results show that the solid volume fraction measurements agree with the theoretical models presented and that …

We have carried out detailed simulations of various fields in the USA (Bada, New Mexico; Heber, California); Mexico (Cerro Prieto); Iceland (Krafla); and Kenya (Olkaria). These simulation studies have illustrated the usefulness of numerical models for the overall evaluation of geothermal systems. The methodology for modeling the behavior of geothermal systems, different approaches to geothermal reservoir modeling and how they can be applied in comprehensive evaluation work are discussed.

Naive applications of Spitzer's theory to very dense plasmas can lead to negative diffusion coefficients. The interdiffusion coefficients in Binary Ionic Mixtures (two species of point ions in a uniform neutralizing background) have been calculated recently using molecular dynamics techniques. These calculations can provide useful benchmarks for theoretical evaluations of the diffusion coefficient in dense plasma mixtures. This paper gives a brief description of a kinetic theoretic approximation to the diffusion coefficient which generalizes Spitzer to high density and is in excellent agreement with the computer simulations. 15 refs., 1 fig., 2 tabs.

The field lines, or integral curves, of a divergence-free field in three dimensions are shown to be topologically equivalent to the trajectories of a Hamiltonian with two degrees of freedom. The consideration of fields that depend on a parameter allow the construction of a canonical perturbation theory which is valid even if the perturbation is large. If the parametric dependence of the magnetic, or the vorticity field is interpreted as time dependence, evolution equations are obtained which give Kelvin's theorem or the flux conservation theorem for ideal fluids and plasmas. The Hamiltonian methods prove especially useful for study of fields in which the field lines must be known throughout a volume of space.

We believe our results have clearly shown Kerr hydroelectric operations and operational constraints have negatively affected Flathead River trout and northern pike populations and the aquatic habitat which support them. Even so, it is possible to mitigate many of these impacts and develop a very important fishery. Trout abundance in the lower Flathead averaged only 19 fish per kilometer, the lowest abundance of trout for a river of this size in Montana. Little main channel spawning by trout was observed and most spawning probably occurs in tributaries. Lower river tributaries support resident populations of brook, rainbow, brown, and cutthroat trout; and a small resident population of bull trout is present in the South Fork of the Jocko River. Using weirs, spawning runs of rainbow and brown trout from the main river were monitored entering the Jocko River and the Post/Mission Creek system. Utilization of Crow Creek by main river trout stocks of trout was limited to the 6 km segment below Crow Dam. Evaluations of tributary spawning gravels showed high levels of silt which would suggest poor survival of trout eggs. Excessive harvest in the tributaries was indicated by analysis of age class structure and abundance of trout greater than …

Abstract: The Voluminous amount of data than can be collected by automatic data acquisition systems during large scale fire tests requires the use of a digital computer for the reduction of data. RAPID is a stand-alone program specifically designed to convert raw instrument voltages collected during such tests into meaningful units. The reduced data can also be used alone or in combinations to obtain quantities that require more than minimal data reduction. The program is written with the ability to accept data from a user defined data acquisition system, with the ability to check the correctness of data included. Through the use of input data provided by the user, the data can be converted into meaningful scientific units. The data can then be presented in tabular or printer plot form, or stored for further processing. This user's guide provides detailed instructions for the use of the program.

A new kind of ion source has been developed in which a metal vapor vacuum arc (MEVVA) is used to produce the plasma from which the ion beam is extracted. The novel and exciting feature of this source is the very high metal ion beam current attainable. A total ion beam current of over 1 Ampere has been extracted from the embodiment of the concept that we're presently using, and this is not a limit of the method. The source was developed to upgrade the uranium ion beam intensity of the Bevatron, LBL's heavy ion synchrotron, for basic nuclear physics research. Other important applications include its use within the Heavy Ion Fusion research effort; for ion implantation; and for other basic research uses. In this paper the source is described briefly, its performance outlined, and its poential and limitations for a variety of applications is discussed.

We consider the charge state distribution of ions produced in the metal vapor vacuum arc plasma discharge. A high current metal ion source, the MEVVA ion source, in which the ion beam is extracted from a metal vapor vacuum arc plasma, has been used to obtain the spectra of multiple charged ions produced within the cathode spots. A computer calculation of the charge state distribution that evolves within the spots via stepwide ionization of ions by electron impact provides a theoretical basis for comparison of the data. In this paper we report on the measured charge state distributions for a wide variety of metallic species and compare these results with the predictions of this theory. 55 refs.

In response to a NASA opportunity, a proposal has been made to study the concept of an Asteroseismology Explorer (ASE). The goal of the ASE would be to measure solar-like oscillations on many (perhaps hundreds) of stars during a 1-year mission, including many members of open clusters. We describe this proposal's observational goals, a strawman technical approach, and likely scientific rewards. 5 refs.