A model has been developed which describes the post-yield behavior of extruded powder aluminum tested biaxially in tension and torsion at elevated temperature. Plots of shear stress versus shear strain for the powder aluminum loaded in simple torsion show that the shear stress increases linearly to the yield point, then remains relatively constant in a pure plastic type of behavior. For the tension-torsion tests, there is an initial linear region up to the yield point followed by a fairly linear decrease in shear stress. A similar linear decrease in axial stress with increasing axial strain is observed in uniaxial tension tests. The model for post-yield behavior of extruded powder aluminum gives a quantified description of the macroscopic material behavior in terms of changes in the laminar powder aluminum structure.

The neutron transport equation is solved by a hybrid method that iteratively couples regions where deterministic (S{sub N}) and stochastic (Monte Carlo) methods are applied. Unlike previous hybrid methods, the Monte Carlo and S{sub N} regions are fully coupled in the sense that no assumption is made about geometrical separation or decoupling. The hybrid method provides a new means of solving problems involving both optically thick and optically thin regions that neither Monte Carlo nor S{sub N} is well suited for by themselves. The fully coupled Monte Carlo/S{sub N} technique consists of defining spatial and/or energy regions of a problem in which either a Monte Carlo calculation or an S{sub N} calculation is to be performed. The Monte Carlo region may comprise the entire spatial region for selected energy groups, or may consist of a rectangular area that is either completely or partially embedded in an arbitrary S{sub N} region. The Monte Carlo and S{sub N} regions are then connected through the common angular boundary fluxes, which are determined iteratively using the response matrix technique, and volumetric sources. The hybrid method has been implemented in the S{sub N} code TWODANT by adding special-purpose Monte Carlo subroutines to calculate the response …

A major problem in evaluating the health risk posed by airborne radon progeny in indoor atmospheres is the lack of available information on the activity-weighted size distributions that occur in the domestic environment. With an automated, semicontinuous, graded screen array system, we made a series of measurements of activity-weighted size distributions in several houses in the northeastern United States. Measurements were made in an unoccupied house, in which human aerosol-generating activities were simulated. The time evolution of the aerosol size distribution was measured in each situation. Results of these measurements are presented.

High-energy-rate-forged (HERF) stainless steels are used as the materials of construction for tritium and deuterium reservoirs. Hydrogen and helium, the decay product of tritium, are known to embrittle stainless steels (1--4). The resistance to hydrogen and helium induced embrittlement is relatively good for HERF stainless steels when compared to annealed stainless steels due to their high number density of dislocations, which act as traps for hydrogen and helium. However, the degree of the embrittlement in these materials can vary considerably because of microstructure and yield strength variations introduced during the forging process. In this study the effect of hydrogen and tritium on the room temperature tensile properties of 21-6-9 stainless steel was measured as a function of HERF yield strength in the range of 500 to 918 MPa. The effect of a microstructures was studied also by conducting tensile tests with both HERF samples and annealed samples.

The goal of this investigation is to develop a description of the biaxial behavior of extruded powder aluminum at elevated temperature. Specimens made of extruded 101 ALCOA (Aluminum Company of America) powder aluminum and specimens made from 1100 commercial aluminum rod are tested biaxially in tension-torsion and compression-torsion loadings at the extrusion temperature. The powder aluminum is examined microscopically and stereological methods are used to give a quantified description of the material behavior in terms of changes in the laminar powder material structure. A model for the biaxial (tension-torsion) behavior of extruded powder aluminum is developed. This description is consistent with a previous analysis of behavior in pure tension.

The chemical decomposition of aqueous alkaline solutions of sodium tetraphenylborate, NaTPB, has been investigated. The focus of the investigation is on the determination of components which influence NaTPB decomposition. Copper(II) ions, solution temperature, and solution pH (hydroxide ion concentration) have all been demonstrated to affect NaTPB stability. Their relationship with each other and the stability of NaTPB has been determined. Based upon this knowledge, a method for stabilizing NaTPB was determined. Decomposition of a NaTPB solution was delayed with the addition of sodium hydroxide. In additional work, the elimination of oxygen from the reaction environment did not prevent NaTPB decomposition in the presence of copper(II) ions but did, however, affect the course of decomposition.

This report is the Materials Sciences Division`s annual report. It contains abstracts describing materials research at the National Center for Electron Microscopy, and for research groups in metallurgy, solid-state physics, materials chemistry, electrochemical energy storage, electronic materials, surface science and catalysis, ceramic science, high tc superconductivity, polymers, composites, and high performance metals.

This report describes recent progress in a fundamental, three-year investigation of the coupled problem of turbulent particle dispersion and thermal radiation transport. The project`s objective is to make measurements of particle size, velocity, number density, temperature and wall radiant heat flux in a parametrically-controlled reactor presently existent a Brigham Young University (BYU). Although the study proposed here is primarily designed to provide experimental data not currently available for the evaluation of turbulent particle dispersion and radiation models, comparisons of analytical predictions and the experimental data obtained will be performed, using appropriate submodels integral to comprehensive pulverized-coal combustion codes existent at BYU.

Establishment of a national ecological research program and institute is discussed. The author says we need to establish a long-term ecological research program to develop a fuller understanding of basic ecosystem process so that scientists can evaluate the health of ecological systems and can predict quantitative and qualitative changes in these systems under foreseeable natural and man-made stress. This area is beginning to be addressed by the CEES, for example, but again with insufficient funding in comparison with other aspects of the US Global Change Program. The major elements of a long-term ecological research program should focus on providing support to develop the theories and hypotheses that dictate the required ecological measurements. EMAP is an excellent example of a large program that could benefit from new funding resources for the development of ecological theory and the study of ecological processes. These understandings are particularly important, and lacking, in system interfaces such as land/water interactions and atmosphere/canopy interactions. Funding stability for long-term ecological research can only be attained through a national commitment to the need. The commitment should be directed in a way that is sensitive to, but not controlled by, policy. Policy issues are particularly important as we attempt to …

We have used Auger photoelectron coincidence spectroscopy to study the M{sub 4,5}VV Auger spectra of GaAs(110). Using this technique, the Ga and As spectra can be separated and studied independently. The lineshape of the As-M{sub 4,5}VV measured in coincidence with the As 3d photoemission line differs significantly from the conventional Auger spectrum. We attribute this to the surface electronic properties of the system. In addition, we have found that the ss-component of the As spectrum is more intense than expected based on calculations using atomic matrix elements. The Ga-M{sub 4,5}VV spectrum, of which only the pp-component is observed, agrees well with that expected from an independent electron model. A first principles electronic structure calculation of a 5-layer GaAs(110) slab has been performed to aid in the interpretation of the Auger spectra.

The Service Level D (faulted) load capacity of a conventional three-bolt pipe-clamp based upon the limit analysis method is presented. The load distribution, plastic hinge locations, and collapse load are developed for the lower bound limit load method. The results of the limit analysis are compared with the manufacturer`s rated loads. 3 refs.

A bench-scale reactor is being used to conduct studies of the conversion of synthesis gas to methanol by a novel process. During the last quarter, the effect of potassium methoxide and Cu-chromite loading on the MeOH formation rate was investigated. The rate obtained with Cu-chromite was compared to that using Cu-ZnO as catalyst. Work also continued on the modification of the experimental equipment to permit on-line monitoring of liquid and gas compositions.

The Savannah River Site (SRS) is a key installation for the production and research of nuclear materials for national defense and peace time applications and has been operating a full nuclear fuel cycle since the early 1950s. Wastes generated include high level radioactive, transuranic, low level radioactive, hazardous, mixed, sanitary, and aqueous wastes. Much progress has been made during the last several years to reduce these wastes including management systems, characterization, and technology programs. The reduction of wastes generated and the proper handling of the wastes have always been a part of the Site`s operation. This paper summarizes the current status and future plans with respect to waste reduction to waste reduction and reviews some specific examples of successful activities.

The fundamental chemistry for selective adsorption of magnetizing reagent on coal-associated minerals to enhance the magnetic susceptibilities of minerals have been established in Phase I study. The application of the results to study the feasibility for coal cleaning has been completed in the Phase II study. The most effective approach to clean Illinois No. 6, Ohio Lower Kittanning, and West Virginia Pocahontas coals using the magnetizing method has been determined. Phase III study is in progress during this quarter. Experimental work includes the determination of various separation parameters, including the separator and matrix selection, magnetic reagent dosage, particle size, magnetic field intensity, and retention time.

Photovoltaics for Utility Scale Applications (PVUSA) is a national public-private partnership that is assessing and demonstrating the viability of utility scale photovoltaic electric generating systems. The project has been designed to provide utilities with hands-on experience needed to evaluate and utilize PV as the technology matures. PVUSA provides manufacturers with a test bed for their products and encourages technology improvement and cost reductions in both the PV modules and other PV system components. PVUSA also generates necessary communication between utilities and the PV industry for successful commercialization. In 1989 PVUSA began to fulfill its primary goal of field testing a wide range of promising American-made PV module technologies and balance-of-system (BOS) configurations in a utility setting. The project began collecting and analyzing data and initiated the necessary technology transfer activities for commercial dialog and technical information exchange between the PV industry and utility users, which continued into 1990.

During the previous quarter, a new approach for the deploymerization of the coal macromolecule was tried. This was aimed towards carbon-carbon bond cleavage in presence of strong bases. Such bond cleavage reactions are well known with the alkali metals. Electron transfer reactions take place from the metals to the aromatic nuclei resulting in the formation ofanion-radicals (or dianions) which subsequently undergo carbon-carbon bond cleavage. In our work instead of using the alkali metals, we have used strong bases to cleave the carbon-carbon bonds in hydrocarbons, and have suggested that hydrocarbon elimination reactions occur. Such anionic fragmentation reactions involving strong bases are not very well established. However, we have obtained circumstantial evidence that such bond cleavage reactions do take place in some coal systems. For example, when the high rank Lower Kittaming coal, PSOC 1197, was treated with Lochmann`s base (equimolar mixture of n-butyllithiun and potassium tert-butoxide) in refluxing heptane and quenched with ammonium chloride and reethanol, the pyridine solubility of the product increased from 5% (raw coal) to 39%. A similar increase in solubility due to base treatment was also observed in a separate study for another high rank coal, Pocahontas No. 3 from the Argonne National Laboratory Premium Sample …

Our goal is to develop the tools of mutational spectrometry in order to discover the cause(s) of genetic change in somatic and germinal cells in humans. Our study of the spectrum of point mutations in human mitochrondrial DNA sequences has revealed that there are multiple point mutation hotspots in each of four separate sequences in the mitochrondrial genome. These spectra were revealed by a combination of high fidelity PCR (modified T{sub 7} polymerase) and denaturing gradient gel electrophoresis which has a limit of detection of about 10{sup {minus}3}. There appear to be identical hotspot mutations in both cultured B cell and fresh human blood T cell samples.

The objective of this work is to investigate, in the laboratory, the parameters associated with a chemically assisted in situ recovery procedure, using hydrogen chloride (HCI), carbon dioxide (CO{sub 2}), and steam (H{sub 2}O), to obtain-data useful to develop a process more economic than existing processes and to report all findings. The technical progress of the project is reported. The progress of the project is that experiment preparations are underway. Reactor design, process design, and experiment design have been completed. The laboratory to be used has required extensive clean-up, and is nearly ready. Safety considerations are underway. Finally, an initial literature search has revealed some important aspects that need to be considered.

Ongoing work includes the characterization of coal pyrites, the floatability evaluation of typical US coal samples, the flotation behavior of coal pyrites, the electrochemical measurement of the surface properties of coal pyrites, and the characterization of species produced at pyrite surfaces.

Research is reported in 3 areas: reduced dimensionality theory of atom-diatom reactions (D+H{sub 2}, H+D{sub 2}, Cl+HCl), reduced dimensionality theory of diatom-diatom reactions (H{sub 2}+A{sub 2}{r_arrow}H+HA{sub 2}, H{sub 2}+CN{r_arrow}H+HCN), and L{sup 2} calculations of resonances (photodetachment spectra of ClHCl{sub {minus}} and IHI{sup {minus}}, H+CO system).

Previous results have shown that the medium pH, the composition of the medium and concentration of medium constituents significantly affect the ratio of ethanol to acetate in the product stream when fermenting CO, CO{sub 2} and H{sub 2} in synthesis gas to products by Clostridium ljungdahlii. An additional batch study was carried out varying the agitation rate at pH 4, 4.5 and 5.0. It was speculated that increased agitation rates in combination with low pH might result in increased ethanol production while, at the same time, yielding higher cell concentrations which could eventually result in higher ethanol concentrations.

A three-stage thin-film detector for the identification of heavy ion fragments was investigated in beam at HHIRF. An experiment on Eu-152 for the purposes of calibrating a four-crystal Germanium polarimeter was performed. The instrument was then used in an experiment to establish polarities for the low-lying transitions in {sup 82}Sr. The spectral fitting code ROBFIT was applied to the data analysis and shown to perform well on the extraction of weak peaks in high background situations.

Both silver catalyzed and direct electrochemical oxidation of organic species are examined in analytical detail. This paper describes the mechanisms, reaction rates, products, intermediates, capabilities, limitations, and optimal reaction conditions of the electrochemical destruction of organic waste. A small bench-top electrocell being tested for the treatment of small quantities of laboratory waste is described. The 200-mL electrochemical cell used has a processing capacity of 50 mL per day, and can treat both radioactive and nonradioactive waste. In the silver catalyzed process, Ag(I) is electrochemically oxidized to Ag(II), which attacks organic species such as tributylphosphate (TBP), tetraphenylborate (TPB), and benzene. In direct electrochemical oxidation, the organic species are destroyed at the surface of the working electrode without the use of silver as an electron transfer agent. This paper focuses on the destruction of tributylphosphate (TBP), although several organic species have been destroyed using this process. The organic species are converted to carbon dioxide, water, and inorganic acids.

Ongoing work includes the characterization of coal pyrites, the floatability evaluation typical US coal samples, the flotation behavior of coal pyrites, the electrochemical measurement of the surface properties of coal pyrites, and the characterization of species produced at pyrite surfaces.