A double-peak, energy-dependent Breit-Wigner model of the E1 gamma-ray strength function was applied to nuclei from As to Rh, to predict their neutron capture cross sections and capture gamma-ray spectra. A consistent set of model parameters was obtained in this mass region to describe the step in the low-energy tail of the E1 strength function. This step allows agreement with photonuclear data at high energies, the correct GAMMA/sub gamma/ to be obtained for agreement with neutron capture cross-section data, and the calculation of the observed hardness in the capture gamma-ray spectra. For nuclei at or near the closed, N = 50 shell, however, the double-peak assumption breaks down. In these cases, good results are still obtained if the same set of model parameters is applied, except that the E1 strength function is formulated in terms of the first, narrower peak. 8 figures.

The study of ecosystems is aided by representing structural and functional groups of organisms or processes as discrete components. A complex compartment model will explicitly map pathways from one compartment to another and specify transfer rates. This quantitative description allows insight into the dynamics of flow of nutrients, toxic chemicals, radionuclides, or energy. Three new indices that calculate compartment-specific probabilities of occurrence and recycling and illustrate the problem of applying these indices to ecosystem models are presented.

In 1978 the magnetic field shapes of six ISABELLE prototype dipole magnets were measured in detail. All the harmonic terms that are forbidden by symmetry in dipole magnets are found to have values that are zero to within the allowed tolerances. This result indicates that the random errors in conductor placement are within tolerances and that the assembly techniques are satisfactory in this regard. However, the first allowed error term in a dipole magnet, the sextupole term, is much too large, and varies greatly from magnet to magnet resulting in field errors at the edge of the desired good field region that are 10/sup -3/ of the central field value, whereas the tolerable field errors are of the order of 10/sup -4/ of the central field value. This large sextupole term has been traced to assembly errors which yield a coil assembly which instead of being circular in cross section is racetrack shaped, with the vertical axis being 10 to 20 thousandths of an inch greater than the horizontal axis. This problem will be corrected in the future production series.

The giant dipole (GD) parameters of peak energy, width, and cross section were satisfactorily correlated for elements from V to Bi, assuming two overlapping peaks with a separation dependent on deformation. The energy dependence of the GD resonance is assumed to have a Breit-Wigner form, but with an energy-dependent width. The resulting gamma-ray strength function model is used to predict neutron capture cross sections and gamma-ray spectra for isotopes of Ta, Os, and Au. 23 references.

Studies of parameter variability by Monte Carlo analysis are reviewed using repeated simulations of the model with randomly selected parameter values. At the beginning of each simulation, parameter values are chosen from specific frequency distributions. This process is continued for a number of iterations sufficient to converge on an estimate of the frequency distribution of the output variables. The purpose was to explore the general properties of error propagaton in models. Testing the implicit assumptions of analytical methods and pointing out counter-intuitive results produced by the Monte Carlo approach are additional points covered.

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)

A perspective on the use of simulation modeling as one working component of a complex ecosystem research project is presented. Experiences with modeling in the context of a research program dealing with nutrient dynamics in stream ecosystems are documented. As the project progressed, the role of modeling changed, resulting in four distinct models, each developed for a specific purpose. The models have been used to screen initial hypotheses, set up details of the experimental design, analyze results, and serve as a logical framework for investigating mechanistic details of the ecosystem. Through time, individual models were discarded, not because they were inadequate, but because they were irrelevant to the next stage of the project. It was particularly interesting to note how the importance of validation, as well as its characteristics, have changed during this process.

The paper describes the development of the ion source for neutral beam injection heating of PDX plasma. After a brief description of the plasma generator, the performance characteristics of the source, with different types of grids, are described. Based on test stand results it is concluded that at least two different versions of the source should be able to meet and even exceed the neutral power and energy requirements expected out of PDX injectors.

Cross sections for this reaction were determined in the range 5.3 to 9 MeV using a previously-reported pulsed-accelerator technique to measure gamma ray activity from 3.75 m /sup 52/V. Very few experimental data have been reported for this reaction, and little was known about the threshold region prior to the present experiment. The results of this work (in conjunction with other available cross section information) were used in the computation of fission-spectrum averages which are of interest for reactor applications.

Because the character of the scattering changes markedly from /sup 6/Li to /sup 12/C projectiles, a study of the /sup 9/Be + /sup 28/Si system was undertaken to examine the transition region. Data were measured at 121.0 and 201.6 MeV. Low-energy data of other investigators were used to carry out global optical model searches. It was found that the elastic scattering of /sup 9/Be from /sup 28/Si is dominated at all energies by relatively strong absorption. This removes much of the sensitivity to the real potential, and even elastic scattering data spanning a range of energies from 13 to 201 MeV do not allow a unique determination of the potential parameters. There is at least circumstantial evidence that /sup 6/Li scattering at low energies (and by implication also /sup 9/Be scattering) may be strongly influenced by breakup processes, although it is not clear that the mechanism is the same. 3 figures, 1 table. (RWR)

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.

Muon rates and polarizations have been measured on several beam channels at LAMPF to characterize muon production from the primary target surface or adjacent volume. To produce these surface or cloud beams, the channel is tuned to accept beam directly from the target. The measurements range from 20 to 200 MeV/c in muon momentum at production angles of 20, 45, and 65/sup 0/. Both ..mu../sup +/ and ..mu../sup -/ rates, and ..mu../sup +/ polarization were measured. Surface beam polariztion is close to 100%, while cloud beam polarization is low. The surface ..mu../sup +/ rate dependence upon proton beam depth in the target is studied.

During the last few decades interest in negative-hydrogen ion sources has been directed mainly toward synchrotron and other particle accelerator applications, with emphasis on high current densities delivered for short pulses. But within the last several years there has been an awareness in the magnetic fusion program of the future need for negative ions as a means for generating high energy neutral beams, beams with energies above a few hundred keV. Negative ions seem to be the only effective intermediary for efficiently producing such beams. Although methods for generating negative ion beams have relied upon synchrotron concepts, the requirements for fusion are very different: here one is interested in more moderate current densities, up to 100 m A cm/sup -2/, but with continuous operation. Proposed source modules would accelerate of the order of 10 A of beam current and deliver several megawatts of beam power. Both H/sup -/ and D/sup -/ beams are being considered for application in different reactor systems. The conceptualization of negative ion sources is now in a very volatile stage. But of the great variety of proposals that have been offered to date, three general areas appear ready for development. These are: first, the double charge …

Local air velocity measurements were obtained with a laser Doppler anemometer near flow blockages in an unheated 7 x 7 rod bundle. Sleeve blockages were positioned on the center nine rods to create an area reduction of 90% in the center four subchannels of the bundle. Experimental results indicated that severe flow disturbances occurred downstream from the blockage cluster but showed only minor flow disturbances upstream from the blockage. Flow reversals were detected downstream from the blockage and persisted for approximately five subchannel hydraulic diameters. The air velocity profiles were in excellent agreement with water velocity data previously obtained at essentially the same Reynolds number. Subchannel average velocity predictions obtained with the COBRA computer program were in good agreement with subchannel average velocities estimated using the measured local velocity data.

Shape resonances in the electronic continuum of molecules induce strong coupling between vibrational and electronic motion over a spectral range much broader than the resonance half width. In photoionization, this coupling causes large deviations from Franck-Condon intensity distributions and strong dependence of photoelectron angular distributions on the vibrational state of the residual ion. In electron scattering, it enhances vibrational excitation. Recent work is reviewed in which new, observable manifestations of this coupling were predicted theoretically and then verified experimentally. 67 references.

Osmotic and activity coefficient data and enthalpy and heat capacity data for NaCl solutions at saturation pressure of water from 0 to 300{sup 0}C and to saturation composition have been simultaneously fit to a 30 parameter equation. The data are reproduced by the equation, in most cases, to within experimental error. Calculated values of the osmotic coefficient, the activity of water, the activity of NaCl, and the heat capacity, enthalpy and entropy of the solution are given in Tables in 25{sup 0}C intervals from 0 to 300{sup 0}C and concentrations from 0.25 to 25 wt% NaCl.

Papers presented are grouped under the following topics: air cleaning; waste volume reduction and preparation for storage; tritium, carbon-14, ozone; containment of accidental releases; adsorbents and absorbents; and off-gas treatment. A separate abstract was prepared for each paper.

The isolation and chromatographic purification of chromophore-containing peptides from the P{sub R} form of phytochrome treated with pepsin and thermolysin are described. From the amino acid sequence and {sup 1}H NMR spectral analysis of phytochromobiliundeca peptide (2) , the structure of the P{sub R) phytochrome chromophore and the nature of the thioether linkage joining pigment to peptide have been established. Confirmatory evidence was obtained from similar analysis of phytochromobilioctapeptide (3) . The implications of this structural assignment with respect to the mechanism of the P{sub R} to P{sub FR} phototransformation is considered.

A surface ionization gauge (SIG) was constructed and used to measure the Cs/sup 0/ flow rate through the emission slit of a surface-plasma source (SPS) of H/sup -/ ions with Penning geometry. The equivalent cesium density in the SPS discharge is deduced from these flow measurements. For dc operation the optimum H/sup -/ current occurs at an equivalent cesium density of approx. 7 x 10/sup 12/ cm/sup -3/ (corresponding to an average cesium consumption rate of 0.5 mg/h). For pulsed operation the optimum H/sup -/ current occurs at an equivalent cesium density of approx. 2 x 10/sup 13/ cm/sup -3/ (1-mg/h average cesium consumption rate). Cesium trapping by the SPS discharge was observed for both dc and pulsed operation. A cesium energy of approx. 0.1 eV is deduced from the observed time of flight to the SIG. In addition to providing information on the physics of the source, the SIG is a useful diagnostic tool for source startup and operation.

The symposium covers heavy ion physics in the energy range 10 to 200 MeV/AMU. Abstracts of individual items from the symposium were prepared separately for the data base. (GHT)

A survey is made of available experimental data on sodium chloride solutions which are used in geothermal energy exploration and development for electrical power production and direct use. The data are classified as thermodynamic, transport and physical; they are useful in the design and development of a geothermal area from brine production through utilization, to brine disposal. An ideal data system for geothermal energy is described.

The pyrochemical coprocessing of spent nuclear fuel by the Salt Transport Process appears to be a potentially viable reprocessing method, not only as an ''exportable proliferation resistant technology,'' but as a domestic reprocessing operation. All operations are nonaqueous and waste generation is in solid form, thus requiring no conversion from aqueous solutions to solids.

The feasibility of demountable superconducting magnet systems has been examined in a design study of a DEALS (Demountable Externally Anchored Low Stress) TF magnet for an HFITR (High Field Ignition Test Reactor) Tokamak device. All parts of the system appear feasible, including the demountable superconducting joints. Measurements on small scale prototype joints indicate that movable pressure contact joints exhibit acceptable electrical, mechanical, and cryogenic performance. Such joints permit a relatively simple support structure and are readily demountable. Assembly and disassembly sequences are described whereby any failed portion of the magnet, or any part of the reactor inside the TF coils can be removed and replaced if necessary.

Individual abstracts are included in the database. (PSB)