The method of cells has been extended to include damage or debonding between all adjacent subcells using a finite element formulation for the original cells assembly. Damage is implemented by placing a nonlinear three-dimensional spring between adjacent subcells. With this arrangement the damage is inherently anisotropic. The ``nonlinear substructure`` cells finite element model is incorporated as a user defined material routine in a general purpose finite element code. The primary motivation for casting the method of cells as a finite element assemblage is to provide a composite constitutive model that facilitates the incorporation of various constituent material models, as well as any level of detail desired in the microstructure geometry. At present, the constituent material models may be anisotropic elastic or isotropic viscoelastic-plastic, while damage evolution is based on the macroscopic strain. The capability of the model is demonstrated through analyses of some simple structures loaded to failure.

Four well-defined indium-dopant/lattice-defect complexes and the non-complexed substitutional indium dopant have been observed by perturbed angular correlation (PAC) spectroscopy in cerium oxide. PAC is a nuclear hyperfine experimental method that detects interactions between a radioactive probe nucleus and nearby atoms. The magnitude and symmetry of those interactions provide a signature for the electromagnetic fields at the probe nucleus. These fields are produced by the arrangement of charges and magnetic moments in the near environment of the probe, so they provide a means of identifying defect structures.

p-Process modeling of some rare but stable proton-rich nuclei requires knowledge of a variety of neutron, charged particle, and photonuclear reaction rates at temperatures of 2 to 3 {times} 10{sup 9} {degrees}K. Detailed balance is usually invoked to obtain the stellar photonuclear rates, in spite of a number of well-known constraints. In this work we attempt to calculate directly the stellar rates for ({gamma},n) and ({gamma},{alpha}) reactions on {sup 151}Eu. These are compared with stellar rates obtained from detailed balance, using the same input parameters for the stellar (n,{gamma}) and ({alpha},{gamma}) reactions on {sup 150}Eu and {sup 147}Pm, respectively. The two methods yielded somewhat different results, which will be discussed along with some sensitivity studies. 16 refs., 7 figs.

Hydrous metal oxide (HMO) materials are inorganic ion exchangers which have many desirable characteristics for catalyst support applications, including high cation exchange capacity, anion exchange capability, high surface area, ease of adjustment of acidity and basicity, bulk or thin film preparation, and similar chemistry for preparation of various transition metal oxides. Cation exchange capacity is engineered into these materials through the uniform incorporation of alkali cations via manipulation of alkoxide chemistry. Specific examples of the effects of Na stoichiometry and the addition of SiO{sub 2} to hydrous titanium oxide (HTO) on ion exchange behavior will be given. Acid titration and cationic metal precursor complex exchange will be used to characterize the ion exchange behavior of these novel materials.

Two new concepts are being developed as possible upgrades to the folded waveguide launcher. The folded stripline is a folded waveguide with an additional conductor positioned inside. The term stripline refers to the resemblance of the design to microwave microstrip line. The conductor provides support for TEM mode propagation, which eliminates cutoff and the nonlinear frequency dependence of the waveguide impedance and phase velocity. A natural extension to the folded stripline is the stacked stripline, which comprises several stacked, independent TEM waveguides. Initial measurements indicate that both concepts have better magnetic flux coupling than the folded waveguide.

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The harmonic content of magnetic field imperfections in the AGS Booster has been determined through careful measurements of the required field corrections of transverse resonances. An analysis of the required correction yielded amplitude and phase information which points to possible sources of imperfections. Dipole and quadrupole imperfections, which are proportional to the field of bending magnets (B), are mainly driven by any misalignment of the magnets. Quadrupole and sextupole imperfections, which are proportional to dB/dt, are driven by imperfections of the eddy-current correction system. The observations also suggest the presence of a remnant field.

The processing of materials using rf and/or microwave power is a broad area that has grown significantly in the past few years. The authors have applied rf and microwave technology in the areas of ceramic sintering, plasma processing, and waste processing. The sintering of ceramics in the frequency range of 50 MHz-28 GHz has lead to unique material characteristics compared to materials that have been sintered conventionally. It has been demonstrated that sintering can be achieved in a variety of materials, including alumina, zirconia, silicon carbide, and boron carbide. In the area of plasma processing, progress has been made in the development and understanding of high density plasma sources, including inductively coupled plasma (ICP) sources. The effects of processing conditions on the ion energy distribution at the substrate surface (a critical processing issue) have been determined for a variety of process gases. The relationship between modeling and experiment is being established. Microwave technology has also been applied to the treatment of radioactive and chemical waste. The application of microwaves to the removal of contaminated concrete has been demonstrated. Details of these programs and other potential application areas are discussed.

Addition of hydroperoxy-alkyl radicals to molecular oxygen leads to chain branching in autoignition and engine knock, and in low temperature oxidation of paraffins. Rate constants and product channels for reaction of hydroperoxy-propyl radicals with O{sub 2} are estimated using thermodynamic properties, bimolecular quantum Kassel analysis and transition state theory. Thermochemistry of relevant molecules and radicals is estimated using group additivity and bond dissociation groups for radicals. Results show that rates of the hydroperoxy-propyl radical addition to O{sub 2} are near their high pressure limits at {ge} 1 atm. Main products at 1--15 atm are stabilization, reverse reaction to hydroperoxy-propyl + O{sub 2} and alkyl carbonyl + OH. Reactions of the stabilized adducts, dissociation rates and product channels are estimated using unimolecular quantum Kassel analysis, because stabilization is the most important hydroperoxy-propyl radical + O{sub 2} product channel. Below 700 K, the stabilized peroxy adducts react primarily to hydroperoxy-carbonyl + OH, products which lead to chain branching. Above 700K, the stabilized peroxy adducts react primarily to hydroperoxy-propyl radical + O{sub 2}, initial reactants, which inhibits the overall oxidation. This switchover in channels correlates well observed negative temperature coefficient behavior for propane oxidation. Rate expressions for reaction of each of the three …

Conversion electrons from the decay of low-lying levels of /sup 237/Np have been measured to detect the population of these levels by gamma-ray decay of the /sup 237/Np shape isomer. Analysis of the 208-keV transition L conversion-electron peak gives an upper limit of about 17 ..mu..b for the population of the 3/2/sup -/ 267-keV level in /sup 237/Np from the shape isomer decay. Model calculations are compared with the measured limit. Improvements are suggested for this experiment. 9 refs., 4 figs.

We report a systematic neutron diffraction study on the coexistence of long-range magnetic order and superconductivity in heavy fermion compounds CeRhl-,M,Ins (M=Ir,Co). In addition to the incommensurate antiferromagnetic component in pure CeRhIn5, new type of antiferromagnetic component is found to concur with appearance of superconductivity in the Ir and Co alloy series. There is no detectable effect of the superconducting transition on magnetic order parameters. We compare those results with similar studies we performed on CeRhIn:, under pressure. We also discuss possible theoretical scenarios.

The first conference on advanced materials for alternative fuel capable directly fired heat engines was held at the Maine Maritime Academy, Castine, Maine. It was sponsored by the US Department of Energy, (Assistant Secretary for Fossil Energy) and the Electric Power Research Institute, (Division of Fossil Fuel and Advanced Systems). Forty-four papers from the proceedings have been entered into EDB and ERA and one also into EAPA; three had been entered previously from other sources. The papers are concerned with US DOE research programs in this area, coal gasification, coal liquefaction, gas turbines, fluidized-bed combustion and the materials used in these processes or equipments. The materials papers involve alloys, ceramics, coatings, cladding, etc., and the fabrication and materials listing of such materials and studies involving corrosion, erosion, deposition, etc. (LTN)

This article discusses L-shell x-ray production cross sections for light ions on Sm, Yb, and Pb.

A systematic investigation of K x-ray production for 20-80 MeV Cl ions in collision with thin self-supporting Cu targets has been conducted. Target and projectile characteristic x rays and radiative electron capture (REC) have been measured as a function of target thickness for incident charge states q < z{sub 1} - 2. At 80 MeV data were also obtained for q = z{sub 1}- 1. Large enhancements in both characteristic x-ray production and REC were observed for q = z{sub 1}- 1. Measured x-ray yields were parametrized vs. target thickness using the model of Betz et al. and least squares fits to the data were performed. Target K x-ray production for q<z{sub 1}-2 is described reasonably well by the CPSSR + ECR theory. For q=z{sub 1} - 1 the enhancement in the x-ray yield is predicted quite well by the method of Gray et al· The mean fluorescence yield for the highly stripped Cl ions is determined and found to increase by a factor of about six over the range 20-80 MeV, having a value (~0.1) nearly equal to the single K-vacancy value at 20 MeV. The radiative lifetime for the projectile ions is found to be ~3 x 10{sup …

Transient solid dynamics simulations are among the most widely used engineering calculations. Industrial applications include vehicle crashworthiness studies, metal forging, and powder compaction prior to sintering. These calculations are also critical to defense applications including safety studies and weapons simulations. The practical importance of these calculations and their computational intensiveness make them natural candidates for parallelization. This has proved to be difficult, and existing implementations fail to scale to more than a few dozen processors. In this paper we describe our parallelization of PRONTO, Sandia`s transient solid dynamics code, via a novel algorithmic approach that utilizes multiple decompositions for different key segments of the computations, including the material contact calculation. This latter calculation is notoriously difficult to perform well in parallel, because it involves dynamically changing geometry, global searches for elements in contact, and unstructured communications among the compute nodes. Our approach scales to at least 3600 compute nodes of the Sandia/Intel Teraflop computer (the largest set of nodes to which we have had access to date) on problems involving millions of finite elements. On this machine we can simulate models using more than ten- million elements in a few tenths of a second per timestep, and solve problems more …

A-prototype explosives detection system that was developed for experimental evaluation of a nuclear resonance absorption techniques is described. The major subsystems are a proton accelerator and beam transport, high-temperature proton target, an airline-luggage tomographic inspection station, and an image-processing/detection- alarm subsystem. The detection system performance, based on a limited experimental test, is reported.

The Ninth Underground Coal Gasification Symposium was held August 7 to 10, 1983 at the Indian Lakes Resort and Conference Center in Bloomingdale, Illinois. Over one-hundred attendees from industry, academia, National Laboratories, State Government, and the US Government participated in the exchange of ideas, results and future research plans. Representatives from six countries including France, Belgium, United Kingdom, The Netherlands, West Germany, and Brazil also participated by presenting papers. Fifty papers were presented and discussed in four formal sessions and two informal poster sessions. The presentations described current and future field testing plans, interpretation of field test data, environmental research, laboratory studies, modeling, and economics. All papers were processed for inclusion in the Energy Data Base.

The Fourteenth Workshop on Geothermal Reservoir Engineering was held at Stanford University on January 24--26, 1989. Major areas of discussion include: (1) well testing; (2) various field results; (3) geoscience; (4) geochemistry; (5) reinjection; (6) hot dry rock; and (7) numerical modelling. For these workshop proceedings, individual papers are processed separately for the Energy Data Base.

It has been recognized for many year`s that the most significant limitation of ICF is the Rayleigh-Taylor (R-T) instability. It limits the distance an ablatively driven shell can be moved to several times its initial thickness. Fortunately material flow through the unstable region at velocity v{sub A} reduces the growth rate to {radical}{sub 1+kL}/{sup kg} {minus}{beta}kv{sub A} with {beta} from 2-3. In recent years experiments using both x-ray drive and smoothed laser drive to accelerate foils have confirmed our understanding of the ablative R-T instability in planar geometry. The growth of small initial modulations on the foils is measured for growth factors up to 60 for direct drive and 80 for indirect drive. For x-ray drive large stabilization is evident. After some growth, the instability enters the non-linear phase when mode coupling and saturation are also seen and compare well with modeling. Normalized growth rates for direct drive are measured to be higher, but strategies for reduction by raising the isentrope are being investigated. For direct drive, high spatial frequencies are imprinted from the laser beam and amplified by the R-T instability. Modeling shows an understanding of this ``laser imprinting.``

The elastic scattering of {sup 9}Be + {sup 28}Si has been measured at laboratory energies of 121.0 and 201.6 MeV. These data have been combined with existing lower energy {sup 9}Be + {sup 28}Si data in order to carry out a global optical model analysis. Calculations employing Woods-Saxon potentials yield good fits to the data without requiring explicitly energy-dependent parameters. In contrast, using a proximity form for the real potential requires an explicitly energy dependent Woods-Saxon imaginary potential in order to achieve comparable quality fits. Notch perturbation calculations have been utilized to locate the radial region of the potential to which the scattering is sensitive. At all energies the imaginary potential is stronger than the real potential at the radius of maximum sensitivity. This dominance of the absorptive potential greatly limits the amount of information which can be gained about the real potential. Comparison of the {sup 9}Be + {sup 28}Si system with other light heavy ion systems such as {sup 6}Li + {sup 28}Si, {sup 12}C + {sup 28}Si, and {sup 16}O + {sup 28}Si suggests that the weak binding of {sup 9}Be may be responsible for the strong absorption in this case.

We are building a 4.7 Tesla-meter room temperature solenoid to be installed in a 10-foot long AGS straight section. This experiment will test the idea of using a partial snake to correct all depolarizing imperfection resonances and also test the feasibility of betatron tune jump in correction intrinsic resonances in the presence of a partial snake.

The author describes a 12-channel VMEbus-based pulse-height analysis board that was designed for use in a high-rate, multidetector, gamma-ray imaging system. This module was designed to minimize dead-time losses and to allow all key parameters to be software controlled. Gamma-ray detectors are connected directly to this module, eliminating the need for additional electronics.

The attendance at the Workshop was similar to last year's with 123 registered participants of which 22 represented 8 foreign countries. A record number of technical papers (about 60) were submitted for presentation at the Workshop. The Program Committee, therefore, decided to have several parallel sessions to accommodate most of the papers. This format proved unpopular and will not be repeated. Many of the participants felt that the Workshop lost some of its unique qualities by having parallel sessions. The Workshop has always been held near the middle of December during examination week at Stanford. This timing was reviewed in an open discussion at the Workshop. The Program Committee subsequently decided to move the Workshop to January. The Tenth Workshop will be held on January 22-24, 1985. The theme of the Workshop this year was ''field developments worldwide''. The Program Committee addressed this theme by encouraging participants to submit field development papers, and by inviting several international authorities to give presentations at the Workshop. Field developments in at least twelve countries were reported: China, El Salvador, France, Greece, Iceland, Italy, Japan, Kenya, Mexico, New Zealand, the Philippines, and the United States. There were 58 technical presentations at the Workshop, of …

The folded waveguide (FWG) launcher is being investigated as an improved antenna configuration for plasma heating in the ion cyclotron range of frequencies (ICRF). A development FWG launcher was successfully tested at Oak Ridge National Laboratory (ORNL) with a low-density plasma load and found to have significantly greater power density capability than current strap-type antennas operating in similar plasmas. To further test the concept on a high density tokamak plasma, a collaboration has been set up between ORNL and Massachusetts Institute of Technology (MIT) to develop and test an 80-MHz, 2-MW FWG on the Alcator C-Mod tokamak at MIT. The radio frequency (rf) electromagnetic modeling techniques and laboratory measurements used in the design of this antenna are described in this paper. A companion paper describes the mechanical design of the FWG.