The light and velocity variations of the Sun and solar-like stars are unique among intrinsic variable stars. Unlike all other standard classes, such as Cepheids, B stars, and white dwarfs, the pulsation driving is caused by coupling with the acoustic noise in the upper convection zone. Each global pulsation mode is just another degree of freedom for the turbulent convection, and energy is shared equally between these g{sup {minus}}-modes and the solar oscillation modes. This driving and damping, together with the normal stellar pulsation mechanisms produce extremely low amplitude solar oscillations. Actually, the surface layer radiative damping is strong, and the varying oscillation mode amplitudes manifest the stochastic convection driving and the steady damping. Thus stability calculations for solar-like pulsations are difficult and mostly inconclusive, but calculations of pulsation periods are as straightforward as for all the other classes of intrinsic variable stars. The issue that is important for the Sun is its internal structure, because the mass, radius, and luminosity are extremely well known. Conventionally, we need the pulsation constants for each of millions of modes. Unknown parameters for constructing solar models are the composition and its material pressure, energy, and opacity, as well as the convection mixing length. …

This paper reviews results on Z{degree} physics from the 1989 run of the Mark 2 experiment at the SLAC Linear Collider. Based on about 20 nb{sup {minus}1} we present results on the mass, width and branching ratios of the Z{degree} boson, the number of light neutrino species, properties of hadronic decays and searches for new particles. 16 refs., 9 figs.

The SP-100 Program is developing a nuclear reactor power system that can enhance and/or enable future civilian and military space missions. The program is directed to develop space reactor technology to provide electrical power in the range of tens to hundreds of kilowatts. The major nuclear assembly test is to be conducted at the Hanford Site near Richland, Washington, and is designed to validate the performance of the 2.4-MWt nuclear and heat transport assembly. 10 refs., 5 figs.

X-ray power diffraction (XPD) is an important tool for the chemical characterization of atmospheric aerosol samples particularly when combined with elemental analysis obtained from x-ray fluorescence (XRF) measurements of the same specimen. The present study focuses on evaluating potential problems associated with XPD analysis of thin layers of particles collected on membrane filters such as would be the case for atmospheric aerosol samples and certain other classes of environmental and geological samples. These samples differ from those previously investigated in quantitative XPD in that absorption effects are minimized but particle size and preferential alignment artifacts may be more significant. The current US Environmental Protection Agency (EPA) aerosol monitoring programs emphasize the use of sampling devices which collect size-segregated aerosols of aerodynamic equivalent diameter less than 10 {mu}m. The approach used in the present experiments is to prepare thin deposits of size-segregated particles and compare the extent to which conventional thin film XRF calibration methods can be applied to quantitative XPD analysis. 13 refs., 1 fig., 7 tabs.

Calculations using a transverse hydrodynamical model with a phase transition in the equation of state are compared to recent heavy ion data. We argue that hydrodynamics alone cannot reproduce the low p{sub T} part of the experimental spectrum. 6 refs., 2 figs.

The Nucleon-Nucleon Bremsstrahlung Workshop was convened at LAMPF on 25--26 January 1990 in order to review the theoretical and experimental aspects of that reaction with focus on a possible new initiative to measure neutron-proton bremsstrahlung using the intermediate-energy, white-spectrum neutron source at the LAMPF/WNR facility. Over the course of this intense day-and-a-half workshop, experts in the field established the historical perspective for both theory and experiment, presented result of recent calculations, and examined new approaches to the difficult neutron-proton bremsstrahlung experiment. Theoretical and experimental working groups generated recommendations for action and actually converged upon a plan for an experimental program, not just a single measurement.

Since the observed fusion cross sections for collisions between heavy ions at subbarrier energies are orders of magnitude larger than would be expected for barrier tunnelling, one is faced with the task of identifying the basic force which is strong enough to overcome the strong Coulomb force and bring about fusion. The two possibilities seem to be excursions of the nuclear surface (and strong nuclear force) due to collective motions of the colliding nuclei and formation of a neck of nuclear matter. The first possibility has received the most attention. However, the systematics of fusion cross sections suggest neck formation is playing an important role. Neck formation can also result in a reseparation of the composite system and we review the experimental information on these reactions at barrier and subbarrier energies. 15 refs., 18 figs.

This paper explores the response of three different materials to high fluence irradiation as observed in recent fusion-related experiments. While helium at fusion-relevant levels influences the details of the microstructure of Fe--Cr--Ni alloys somewhat, the resultant changes in swelling and tensile behavior are relatively small. Under conditions where substantially greater-than-fusion levels of helium are generated, however, an extensive refinement of microstructure can occur, leading to depression of swelling at lower temperatures and increased strengthening at all temperatures studied. The behavior of these alloys is dominated by their tendency to converge to saturation microstructures which encourage swelling. Irradiations of nickel are dominated by its tendency to develop a different type of saturation microstructure that discourages further void growth. Swelling approaches saturation levels that are remarkably insensitive to starting microstructure and irradiation temperature. The rate of approach to saturation is very sensitive to variables such as helium, impurities, dislocation density and displacement rate, however. Copper exhibits a rather divergent response depending on the property measured. Transmutation of copper to nickel and zinc plays a large role in determining electrical conductivity but almost no role in void swelling. Each of these three materials offers different challenges in the interpretation of fission-fusion correlation experiments.

This paper presents the methodology that will be used for the evaluation of alternative disposal concepts for Greater-Than-Class C low-level radioactive waste. The primary focus will be on the technical evaluation of various disposal concepts leading toward the identification of technically feasible disposal systems.

A high intensity experiment was performed to search for free quarks at BNL and CERN using ultra-relativistic beams. The experiment was designed to trap quarks in a Hg target or liquid Ar tank. No free quark candidate was found. Limits from 10{sup {minus}7} to 10{sup {minus}10} quarks per incident ion are reported. 7 refs., 2 figs., 2 tabs.

The transport systems required to feed a beam of highly relativistic electrons into a free electron laser have to satisfy very stringent requirements with respect to isochronicity and achromaticity. In addition, the line has to be tunable to match different operating modes of the free electron laser. Various beamlines emphasizing different aspects, such as quality of isochronicity and achromaticity, simplicity of the design, and space configurations are shown and compared. Solutions are presented having time resolution in the range of 2 to less than 0.5 picoseconds for one percent of energy spread.

Cold iron magnets use the iron yoke and skin for mechanical support of the collared coil assembly. A variety of designs, including horizontally and vertically split yokes, collarless'' magnets and conductor block geometries, have been considered for use with collared coils. This note qualitatively compares the support mechanisms by estimating the amount of coil overcompression'' necessary for the magnet to achieve the same mechanical condition in the cold, powdered state. These designs inspect magnet limitations by suggesting means to reduce the peak coil compressive load, allowing higher central magnetic fields to be reached.

A computational model was developed to evaluate radiation doses to sensitive cells from exposure to radon progeny throughout human bronchial epithelium. The model incorporated current information on nasal and oral filtration efficiencies for unattached radon progeny, characteristics of bronchial deposition by diffusive and inertial processes, mucous clearance and possible transfer of radon progeny to the airway epithelium, locations of target nuclei of secretory and basal cells in different regions of the bronchial tree epithelium, and other features. The model is useful for evaluating absorbed doses to various populations of target cell nuclei, the associated microdosimetric probability densities in specific energy, and the likelihood that target nuclei are hit one or more times by alpha-particle tracks. The model was applied to extrapolating lung cancer risks observed in underground miners to the general population exposed to low-level radon progeny in indoor home environments. The effect of increasing exposure rates by one and two orders of magnitude in both environments was modeled to determine the frequency of radiation events in target cell nuclei. The implications of dosimetric modeling for lung cancer risk analysis were also examined. 28 refs., 5 figs., 5 tabs.

Training radon mitigators and ensuring that they provide high-quality work on the scale necessary to reduce radon to acceptable levels in the large number of homes and schools requiring some mitigation is a challenging problem. The US Environmental Protection Agency and several states have made commendable efforts to train mitigators and ensure that they provide quality services to the public. Expert systems could be used to extend and improve the effectiveness of these efforts. The purpose of this paper is to introduce the radon community to this promising new technology. The paper includes a description of a prototype system developed by Pacific Northwest Laboratory that illustrates several of the capabilities that expert systems can provide, a brief explanation of how the prototype works, and a discussion of the potential roles and benefits of fully-developed expert systems for radon mitigation. 4 refs., 3 figs.

Low-energy compound nucleus emission of complex fragments in the reaction {sup 63}Cu + {sup 12}C is used to infer the associated ridge-line potential. Compound binary emission of complex fragments at higher energies is illustrated for a variety of reactions. Complex fragment emission from 35 and 40 MeV/N {sup 139}La + {sup 12}C, {sup 27}Al, {sup 40}Ca and {sup 51}V reactions has been studied. Multifragment events from these reactions were assigned to sources characterized by their energy and mass through the incomplete-fusion-model kinematics. Excitation functions for the various multifragment channels appear to be nearly independent of the system and bombarding energy. Preliminary comparisons of the data with sequential-statistical-decay calculations are discussed.

Grain boundaries in YBa{sub 2}Cu{sub 3}O{sub 7-x} superconductor thin films grown on (001) MgO by metal-organic chemical vapor deposition (MOCVD) have been characterized using transmission electron microscopy (TEM) and high-resolution electron microscopy (HREM). It was found that the YBa{sub 2}Cu{sub 3}O{sub 7-x} thin films were highly textured with the c axes, or (001) orientation, nearly parallel between grains and perpendicular to the MgO substrate. A majority of the grain boundaries are low-angle boundaries with a tilt angle, {theta}, less than 15{degree}. The low-angle boundaries appear to be strongly faceted on an atomic scale in such a way that the boundary planes tend to be parallel to the (100), (010), or (110) lattice planes in one of the adjacent grains. Almost all of the lattice planes, except for a number of distorted regions along the boundaries, are continuous across the boundaries from one grain to another, accommodating the misorientation with a slight bending of the lattice planes. The small-angle boundaries are shown to consist of arrays of dislocations. A domain structure, formed by the interchange of a and b axes has been observed in large grains. The domain boundaries are strongly faceted with the (100) and (010) lattice planes parallel to …

Catalyzed Electrolytic Plutonium Oxide Dissolution (CEPOD) was first demonstrated at PNL in early 1974 in work funded by EXXON Corporation. That work was aimed at dissolution of Pu-containing residues remaining in mixed-oxide reactor fuels dissolution and was first publicly disclosed in 1981. The process dissolves PuO{sub 2} in an anolyte containing small (catalytic) amounts of elements that form kinetically fast, strongly oxidizing ions. These are continuously regenerated at the anode. Catalysts used, in their oxidized form, include Ag{sup 2+}, Ce{sup 4+}, Co{sup 3+}, and AmO{sub 2}{sup 2+}. This paper reviews the chemistry involved in CEPOD and the results of its application to the dissolution of the Pu content of a variety of PuO{sub 2}-containing materials such as off-standard oxide, fuels dissolution residues, incinerator ash, contaminated soils, and other scrapes or wastes. Results are presented for both laboratory-scale and plant-scale dissolvers. Spin-off applications such as decontamination of metallic surfaces and destruction of organics are discussed. 27 refs., 14 figs.

Emplacement borehole orientation directly impacts many aspects of the Engineered Barrier System (EBS) and interactions with the near field environment. This paper considers the impacts of orientation on the hydrologic portion of the environment and its interactions with the EBS. The hydrologic environments is considered from a conceptual standpoint, the numerical analyses are left for subsequent work. As reported in this paper, several aspects of the hydrological environment are more favorable for long term performance of vertically oriented rather than horizontally oriented Waste Packages. 19 refs., 15 figs.

Thermal analysis of a pin from the FSP-1 fuels irradiation test has been completed. The purpose of the analysis was to provide predictions of fuel pin temperatures, determine the flow regime within the lithium annulus of the test assembly, and provide a standardized model for a consistent basis of comparison between pins within the test assembly. The calculations have predicted that the pin is operating at slightly above the test design temperatures and that the flow regime within the lithium annulus is a laminar buoyancy driven flow. 7 refs., 5 figs.