High-pressure results for nitrogen are reviewed and discussed in terms of phenomena that occur at extreme conditions.

Research activities are reported under the following headings: materials sciences, chemical sciences, nuclear sciences, fossil energy, energy storage systems, and work for others. (DLC)

Hugoniot equation-of-state, shock temperature, and electrical conductivity measurements are reported for fluids believed to be the primary constituents of the planets Uranus and Neptune. The equation-of-state results are compared with calculations performed using a statistical mechanical, chemical equilibrium computer code and electrical conductivities are discussed in terms of the recently measured magnetic field of Uranus. 4 refs., 2 figs., 1 tab.

The Modular High Temperature Gas Cooled Reactor (MHTGR) design meets stringent top-level regulatory and user safety requirements that require that the normal and off-normal operation of the plant not disturb the public's day-to-day activities. Quantitative, top-level regulatory criteria have been specified from US NRC and EPA sources to guide the design. The user/utility group has further specified that these criteria be met at the plant boundary. The focus of the safety approach has then been centered on retaining the radionuclide inventory within the fuel by removing core heat, controlling chemical attack, and by controlling heat generation. The MHTGR is shown to passively meet the stringent requirements with margin. No operator action is required and the plant is insensitive to operator error.

Methods that have been developed in the chemical physics community over the previous decade are applied to problems involving the dynamic chemical behavior of fluids under highly compressed conditions. The methods require detailed structural information about the environment seen by the reacting molecules. These methods are briefly reviewed. Examples for both statically compressed and shock conditions are discussed.

To determine the bed-loading capacities and the effluent iodine concentrations at normal, off-normal, and standby conditions, PNL performed a series of statistically designed parametric tests using a bed of AgZ 12 cm long x 1 cm diameter. In addition, tests were performed to determine the effect of bed length, the effect of a second bed, the effect of extended standby conditions, and the efficiency of hydrogen-reduced AgZ (Ag/sup 0/Z). Results of these experiments are presented in this report.

This report presents progress made at the Stanford Linear Collider (SLC). Design goals of the various components are compared to measurements made on the equipment. 8 figs., 2 tabs. (JDH)

The author reviews past and recent developments in the study of RR Lyrae variables. He provides supporting evidence for a large helium content but remains uncertain as to their masses and luminosities. Time dependent convection is offered as a probable explanation for the double mode pulsations of these stars. 25 refs., 8 figs., 3 tabs.

A simple, inexpensive diagnostic has been developed for time-resolved imaging of repetitive self-luminescent phenomena. An electro-optic birefringent ceramic shutter is employed to perform photographic sampling and yields time resolution of 100 ..mu..sec. Methods of image enhancement in the presence of background light from a finite-contrast shutter are discussed. The system has been applied to the study of plasma evolution in the CDX device. 21 refs., 4 figs.

The modern materials processing technique, ion implantation, has intriguing and attractive features that stimulate the imaginations of scientists and technologists. Success of the technique for introducing dopants into semiconductors has resulted in a stable and growing infrastructure of capital equipment and skills for use of the technique in the economy. Attention has turned to possible use of ion implantation for modification of nearly all surface related properties of materials - optical, chemical and corrosive, tribological, and several others. This presentation provides an introduction to fundamental aspects of equipment, technique, and materials science of ion implantation. Practical and economic factors pertaining to the technology are discussed. Applications and potential applications are surveyed. There are already available a number of ion-implanted products, including ball-and-roller bearings and races, punches-and-dies, injection screws for plastics molding, etc., of potential interest to the machine tool industry.

This report describes a preliminary study to determine whether crystallizer schemes could be effectively used in binary geothermal power plants. An industry and literature search was conducted for models that predict potential scale formation. The results indicated that the theoretical models for predicting not only homogeneous nucleation, but also secondary nucleation are suspect. (ACR)

On the basis of simple heuristic models, we show that atomic electrons can amplify fields observed at the nucleus, generate harmonics, and drive higher multipolarities. Considered is a model with the nucleus at the focus of a uniformly charged ellipsoid. It amplifies an oscillating external electric field and produces an oscillating electric-field gradient but no higher derivatives. The electric field has only odd harmonics and the electric-field gradient has only even harmonics. There is an optimum intensity for driving each harmonic. Commented on is the relevance of these results to the U/sup 235/ experiment and to the gamma-ray laser.

Bhabha scattering and multi-hadronic e/sup +/e/sup -/ annihilation events have been observed in the AMY detector at ..sqrt..s = 50 GeV and ..sqrt..s = 52 GeV at the TRISTAN e/sup +/e/sup -/ storage ring. Here we report the results of a preliminary analysis of the properties of these events. We present results for the e/sup +/e/sup -/ ..-->.. e/sup +/e/sup -/, e/sup +/e/sup -/ ..-->.. ..gamma gamma.. and e/sup +/e/sup -/ ..-->.. ..mu../sup +/..mu../sup -/ differential cross sections as well as for R, the ratio of e/sup +/e/sup -/ annihilation into hadrons to that for dimuons. In addition we present results on the characteristics of the final state hadrons in the annihilation events.

Extended Electron Energy Loss Fine Structure (EXELFS) is a technique which is sensitive to the local atomic environment surrounding atoms. The ability to perform EXELFS measurements with the use of an electron microscope enables one to study materials properties at high spatial resolution. Its use as a method to evaluate amorphous materials is especially noteworthy since EXELFS is sensitive to the structure and composition within near neighbor distances of specific types of atoms. The materials used in this study included single crystal SiC, single crystal SiC made amorphous by ion implantation with chromium, and single crystal SiC made amorphous under a converged 300 kV electron beam. EXELFS results, based upon the Si K edge, exhibit significant differences for crystalline SiC versus the SiC made amorphous by ion implantation. The position of peaks in the radial distribution function (RDF), representing the Si-C and the Si-Si interatomic bonds, indicate an expansion in the nearest neighbor distances for the ion implanted amorphous SiC. Also the Si-Si/Si-C peak intensity ratio for the amorphous material was significantly lower than that for crystalline SiC. These results imply that the tetrahedral (Si-C) bonds are retained to a greater degree than the longer Si-Si bonds. A loss in …

A vertex chamber has been constructed for use in the Mark III experiment. The chamber is positioned inside the current main drift chamber and will be used to trigger data collection, to aid in vertex reconstruction, and to improve the momentum resolution. This paper discusses the chamber's construction and performance and tests of the prototype.

Newsletter of the Texas Air Control Board including information about the Board as well as news, events, and other relevant information related to air quality in Texas.

By using SN 1987a as a 'source' of neutrinos with energy approx.10 MeV we place limits on the couplings of neutrinos with cosmic background particles. Specifically, we find that the Majoron-electron neutrino coupling must be less than about 10/sup -3/; if neutrinos couple to a massless vector particle, its dimensionless coupling must be less than about 10/sup -3/; and if neutrinos couple with strength g to a massive boson of mass M, then g/M must be less than 12 MeV/sup -1/. 11 refs., 3 tabs.

This is an experimental review of light quark spectroscopy from e/sup +/e/sup -/ production and ..gamma gamma.. collision results presented at the 2nd International Conference on Hadron Spectroscopy at KEK, Japan. The recent results in ..gamma gamma.. production have evidence for the J/sup PC/ = 1/sup + +/, E/f/sub 1/(1420) and D/f/sub 1/(1285), mesons from the TPC and Mark II collaborations and upper limits for pseudoscalar resonances from the Crystal Ball collaboration. The results in J/psi reactions include D/f/sub 1/(1285) meson production in radiative decays and a complete measurement of the hadronic decays into pseudoscalar-vector pairs from the DM2 collaboration and evidence for phi phi production in radiative decays and a study of the iota line shape from the Mark III collaboration. A short review of simple theoretical ideas is presented.

The latest results from a number of experiments on searches for rare decays of the charmed D-mesons are summarized. This talk reports on upper limits on flavor changing weak neutral current reactions and on processes that do not conserve the lepton family number.

Multiple scale methods are used to treat several ingredients of the theory of atoms in strong electromagnetic fields. First, a focused electromagnetic field is expanded. Second, a classical electron is described giving the ponderomotive potential. Third, the quantum electron is treated in the WKB approximation. Fourth, the one dimensional quantum harmonic oscillator is solved; and last the one dimensional square well, showing the low intensity limit of the theory.

The dramatic influence of multiwave mixing processes on resonant multiphoton excitation of dipole-allowed quantum transitions are discussed. Brief comparisons are made between different theoretical approaches used in treating the same underlying physics, and between the predictions and available experimental manifestations of the phenomenon for three-photon and five-photon induced processes.

It is shown that the d-t fusion reaction can be modified by polarizing nuclear spins. The ways in which this improves reactor performance are mentioned and the feasibility of the process of spin polarization for magnetic fusion is discussed. 18 refs.

An equation of state is computed for quark matter interacting through a phenomenological potential in the Hartree-Fock approximation. It is shown that for color-independent confining potentials, it can be approximated by the Hartree result and leads to a first order mass phase transition. For color-dependent confining potentials, a phase transition from a Fermi sphere to a Fermi shell is possible.

The main and catastrophic phase of eruption in Long Valley occurred 0.73 m.y. ago with the eruption of over 600 km/sup 3/ of rhyolitic magma. Subsequent collapse of the roof rocks produced a caldera which is now elliptical in shape, 32 km east-west by 17 km north-south. The caldera, like other large Quarternary silicic ash-flow volcanoes that have been studied by various workers, has a nearly coincident Bouguer gravity low. Earlier interpretations of the gravity anomaly have attributed the entire anomaly to lower density rocks filling the collapsed structure. However, on the basis of many additional gravity stations and supporting subsurface data from several new holes, a much more complex and accurate picture has emerged of caldera structure. From a three-dimensional inversion of the residual Bouguer gravity data we can resolve discontinuities that seem to correlate with extensions of pre-caldera faults into the caldera and faults associated with the ring fracture. Some of these faults are believed related to the present-day hydrothermal upflow zone and the zone of youngest volcanic activity within the caldera.