The biogeochemical and physical processes operating in the oceans create substantial geographical and vertical variations in the oceanic distribution of many trace elements. These variations are brought about by diverse mechanisms and involve trace elements of a wide spectrum of physicochemical and biological behavior. Thus, a knowledge of these trace element distributions can help characterize some of the ocean processes in which they participate. (auth)

Possible uses of pattern recognition techniques for solving complex scientific problems are discussed, and previous experience in using the pattern recognition computer code RECOG to solve materials problems, specifically in determining the mechanical properties of high explosives, is described. (LCL)

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This paper discusses decontamination methods for LWRs. Emphasis is on the chemical cleaning of primary systems and contaminated equipment and components. The equipment is composed primarily of stainless steel, Inconel, Zircaloy, and a few other materials. Variables affecting efficiency are discussed. 10 figures. (DLC)

Candidate materials are discussed and initial choices made for the critical elements in a liquid Li-Na Cauldron Tandem Mirror blanket and the General Atomic Sulfur-Iodine Cycle for thermochemical hydrogen production. V and Ti alloys provide low neutron activation, good radiation damage resistance, and good chemical compatibility for the Cauldron design. Aluminide coated In-800H and siliconized SiC are materials choices for heat exchanger components in the thermochemical cycle interface.

Nb/sub 3/Sn is a strain-sensitive superconductor which exhibits large changes in properties for strains of less than 1 percent. The critical current density at 12 T undergoes a reversible degradation of a factor of two for compressive strains of about 1 percent and undergoes an irreversible degradation for tensile strains on the Nb/sub 3/Sn greater than 0.2 percent. Consequently, the successful application of Nb/sub 3/Sn in large high-field magnets requires a complete understanding of the mechanical properties of the conductor. One conductor which is being used for many applications consists of filaments of Nb/sub 3/Sn in a bronze matrix, and much progress has been made in understanding the mechanical behavior of this composite. The Nb/sub 3/Sn filaments are placed in compression due to the differential thermal contraction between Nb/sub 3/Sn and bronze which occurs when the composite is cooled from the Nb/sub 3/Sn formation temperature (typically 700/sup 0/C) to the 4.2/sup 0/K operating temperature. The general behavior of the critical current when this conductor is subjected to a tensile stress is an increase to a maximum when the compressive strain on the Nb/sub 3/Sn is relieved, followed by a decrease as the Nb/sub 3/Sn filemants are placed in tension. The …

Preliminary calculations of Q and magnet designs are presented for three different versions of tandem mirror reactors (TMR) using thermal barriers to enhance plug potentials by auxiliary electron heating. These three versions, called A-cell-barrier TMR, axisymmetric-barrier TMR, and inside-barrier TMR, exhibit reduced plug density (n/sub p/ << 10/sup 19/ m/sup -3/) and less required magnetic mirror field (B/sub mirror approx. = 9 T) compared to TMR designs without thermal barriers. A-cell barrier TMR Q's range from 5 to 25 depending on the central-cell length (L/sub c/ = 100 to 200 m) and peak center-cell beta ..beta../sub c/ (0.3 to 0.7) allowed by MHD stability. Axisymmetric-barrier TMR Q's range from 14 at L/sub c/ = 100 m to 30 at L/sub c/ = 200 m, if peak ..beta../sub c/ = 1. From a global equilibrium model for the inside-barrier TMR, Q values greater than 15 are achieved for ..nu.. = 0.5 in the modified Boltzmann relation for the plug potential. Even higher Q's are obtained using ECRF heating in the barrier to create a hot, mirror-trapped electron population. TMR's burning D-D as a fuel have been analyzed with a modified version of the global equilibrium model and under the assumption of …

NOVANET is a control system oriented fiber optic local area network that was designed to meet the unique and often conflicting requirements of the Nova laser control system which will begin operation in 1984. The computers and data acquisition devices that form the distributed control system for a large laser fusion research facility need reliable, high speed communications. Both control/status messages and experimental data must be handled. A subset of NOVANET is currently operating on the two beam Novette laser system.

The analyzing power in 28 GeV/c proton-proton elastic scattering was measured at P/sub perpendicular to//sup 2/ = 5.95 and 6.56 (GEV/c)/sup 2/ y/sub g/ a polarized proton target and an unpolarized proton beam at the Brookhaven National Laboratory AGS. Results indicate that the analyzing power, A, is rising sharply with P/sub perpendicular to//sup 2/. Previous measurements of the analyzing power, A, in p + p ..-->.. p + p suggested a rise in A at large-P/sub perpendicular to//sup 2/, but the statistical uncertainty in the highest point at P/sub perpendicular to//sup 2/ = 5.95 (GeV/c)/sup 2/ made it impossible to determine the magnitude of the increase. In an effort to clarify this situation, we made new measurements of A at P/sub perpendicular to//sup 2/ = 5.95 and 6.56 (GeV/c)/sup 2/. An unpolarized beam of typically 5 x 10/sup 10/ 28 GeV/c protons from the AGS at Brookhaven National Laboratory was incident upon the University of Michigan polarized proton target. This target contains irradiated ammonia beads cooled to 0.5/sup 0/K by a /sup 3/He-/sup 4/He evaporation refrigerator, in a 2.5 T magnetic field. The polarizing transitions are driven by a 70 GHz microwave system. The polarization of the hydrogen protons is …

A combination of theoretical estimates, based on a ..lambda..N potential model, and phenomenological analysis of hypernuclear data is used to determine a set of four P/sub N/s/sub ..lambda../ two-body matrix elements which characterize the spin dependence of the ..lambda..N interaction in the p shell. The central spin-spin and the ..lambda.. spin-orbit matrix elements are most strongly constrained by existing data. The spin dependence is weak in the sense that s/sub ..lambda../ doublet splittings are predicted to be of order 100 keV except for the special case of /sub ..lambda..//sup 7/Li where the central spin-spin interaction dominates and the ground-state doublet separation is likely to be about 600 keV. The results of recent (K/sup -/, ..pi../sup -/..gamma..) experiments at the Brookhaven AGS are interpreted in terms of the ..lambda..N effective interaction.

Summary of lectures presented in the Shell Seminar Series at the national convention of the National Science Teachers Association, April 7-10, 1988. Topics covered are: The Standard model, symmetry breaking, the superconducting supercollider, physics at the TEV scale, and the early universe.

We review pertinent aspects of the history of the space launch capabilities of the United States and survey its present status and near-term outlook. Steps which must be taken, pitfalls which much be avoided, and a core set of National options for re-acquiring in the near term the capability to access the space environment with large payloads are discussed. We devote considerable attention to the prospect of creating an interim heavy-lift space launch vehicle of at least 100,000 pound payload-orbiting capacity to serve National needs during the next dozen years, suggesting that such a capability can be demonstrated within 5 years for less than $1 B. Such capability will apparently be essential for meeting the first-phase goals of the President's Space Exploration Initiative. Some other high-leverage aspects of securing American access to space are also noted briefly, emphasizing unconventional technological approaches of presently high promise.

Recent ROSAT and EUVE detections of spin-powered neutron stars suggest that many emit ``thermal`` radiation, peaking in the EUV/soft X-ray band. These data constrain the neutron stars` thermal history, but interpretation requires comparison with model atmosphere computations, since emergent spectra depend strongly on the surface composition and magnetic field. As recent opacity computations show substantial change to absorption cross sections at neutron star photospheric conditions, we report here on new model atmosphere computations employing such data. The results are compared with magnetic atmosphere models and applied to PSR J0437-4715, a low field neutron star.

Recirculating induction accelerators have been studied as a potential low cost driver for inertial fusion energy. At LLNL, we are developing a small (4.5-m diameter), scaled, experimental machine which will demonstrate many of the engineering solutions of a full scale driver. The small recirculator will accelerate singly ionized potassium ions from 80 to 320 keV and 2 to 8 mA, using electric dipoles for bending and permanent magnet quadrupoles for focusing in a compact periodic lattice. {ital While very compact, and low cost, this design allows the investigation of most of the critical physics issues associated with space-charge-dominated beams in future IFE power plant drivers.} This report describes the recirculator, its mechanical design, its vacuum design, and the process for aligning it. Additionally, a straight magnetic transport experiment is being carried out to test diagnostics and magnetic transport in preparation for the recirculator.

This report contains viewgraphs on a object-oriented programming language called Python. The basic elements of Python and its new numerical extension are discussed.

This paper reviews what is known about edge localized modes (ELMs), with an emphasis on their effect on the scrape-off layer and divertor plasmas. ELM effects have been measured in the ASDEX-U, C-Mod, COMPASS-D, DIII-D, JET, JFT-2M,JT-60U, and TCV tokamaks and are reported here. At least three types of ELMs have been identified and their salient features determined. Type-1 giant ELMs can cause the sudden loss of up to 10-15% of the plasma stored energy but their amplitude ({Delta}W/W) does not increase with increasing power. Type- 3 ELMs are observed near the H-mode power threshold and produce small energy dumps (1-3% of the stored energy). All ELMs increase the scrape- off layer plasma and produce particle fluxes on the divertor targets which are as much as ten times larger that the quiescent phase between ELMs. The divertor heat pulse is largest on the inner target, unlike that of L-Mode or quiescent H-mode; some tokamaks report radial structure in the heat flux profile which is suggestive of islands or helical structures. The power scaling of Type-1 ELM amplitude and frequency have been measured in several tokamaks and has recently been applied to predictions of the ELM Size in ITER. Concern over …

The National Ignition Facility (NIF) is a proposed US Department of Energy inertial confinement laser fusion facility. The candidate sites for locating the NIF are: Los Alamos National Laboratory, Sandia National Laboratory, the Nevada Test Site, and Lawrence Livermore National Laboratory (LLNL), the preferred site. The NIF will operate by focusing 192 laser beams onto a tiny deuterium- tritium target located at the center of a spherical target chamber. The NIF mission is to achieve inertial confinement fusion (ICF) ignition, access physical conditions in matter of interest to nuclear weapons physics, provide an above ground simulation capability for nuclear weapons effects testing, and contribute to the development of inertial fusion for electrical power production. The NIF has been classified as a radiological, low hazard facility on the basis of a preliminary hazards analysis and according to the DOE methodology for facility classification. This requires that a safety analysis be prepared under DOE Order 5481.1B, Safety Analysis and Review System. A draft Preliminary Safety Analysis Report (PSAR) has been written, and this will be finalized later in 1996. This paper summarizes the safety issues associated with the operation of the NIF. It provides an overview of the hazards, estimates maximum routine …

The response matrix, consisting of the closed orbit change at each beam position monitor (BPM) due to corrector magnet excitations, was measured and analyzed in order to calibrate a linear optics model of SPEAR. The model calibration was accomplished by varying model parameters to minimize the chi-square difference between the measured and the model response matrices. The singular value decomposition (SVD) matrix inversion method was used to solve the simultaneous equations. The calibrated model was then used to calculate corrections to the operational lattice. The results of the calibration and correction procedures are presented.

Using multi-ion MGPT interatomic potentials derived from first- principles generalized pseudopotential theory, we have performed accurate atomistic simulations on the energetic of dislocation motion in the bcc transition metal Mo. Our calculated results include the (110) and (211) generalized stacking fault ({gamma}) energy surfaces, the Peierls stress required to move an ideal straight <111> screw dislocation, and the kink-pair formation energy for nonstraight screw dislocations. Many-body angular forces, which are accounted for in the present theory through explicit three- and four-ion potentials, are quantitatively important to such properties for the bcc transition metals. This is demonstrated explicitly through the calculated {gamma} surfaces, which are found to be 10-50% higher in energy than those obtained with pure radial-force models. The Peierls stress for an applied <111>/{l_brace}112{r_brace} shear is computed to be about 0.025{mu}, where {mu} is the bulk shear modulus. For zero applied stress, stable kink pairs are predicted to form for kink lengths greater than 4b, where b is the magnitude of the Burgers vector. For long kinks greater than 15b, the calculated asymptotic value of the kink-pair formation energy is 2.0 eV.

Mixed dark matter scenario can reconcile the COBE data and the observed large scale structure. So far the massive neutrino with a mass of a few eV has been the only discussed candidate for the hot dark matter component. We point out that the hadronic axion in the so-called hadronic axion window, f{sub a} {approx} 10{sup 6} GeV, is a perfect candidate as hot dark matter within the mixed dark matter scenario. The current limits on the hadronic axion are summarized. The most promising methods to verify the hadronic axion in this window are the resonant absorption of almost-monochromatic solar axions from M1 transition of the thermally excited {sup 57}Fe in the Sun, and the observation of the ''axion burst'' in water Cerenkov detectors from another supernova.

Cyanate ester resins offer advantages as composite matrices because of their high thermal stability, low outgassing, low water absorption, and radiation resistance. This paper describes the results of a processing study to develop a high-strength hoop-wound composite by the wet-filament winding method using Toray TI 000G carbon fiber and YLA RS- 14A cyanate ester resin as the constituent materials. The study shows that the cyanate ester resin has a broad process envelope but that an inert-atmosphere cure is essential for obtaining optimum resin and composite properties. Minimizing moisture exposure prior to and during cure is also crucial as it affects the glass transition temperature of the resin and composite. Composite cylinders wound and cured with these methods yielded excellent ring tensile strengths both at room and elevated temperature. A summary of the measured mechanical and thermal property data for these composites is presented. Potential applications for these materials include flywheeI energy storage systems for space and satellite structures.

The recently completed Department of Energy (DOE) and industry sponsored Cooperative Research and Development Agreement (CRADA) entitled, ''Electron Beam Curing of Polymer Matrix Composites,'' determined that the interlaminar shear strength properties of the best electron beam cured IM7/epoxy composites were 19-28% lower than autoclave cured IM7/epoxy composites (i.e. IM7/977-2 and IM7/977-3). Low interlaminar shear strength is widely acknowledged as the key barrier to the successful acceptance and implementation of electron beam cured composites in the aircraft/aerospace industry. The objective of this work was to improve the interlaminar shear strength properties of electron beam cured composites by formulating and evaluating several different fiber sizings or coating materials. The researchers have recently achieved some promising results by having discovered that the application of epoxy-based, electron beam compatible sizings or coatings onto surface-treated, unsized IM7 carbon fibers improved the composite interlaminar shear strength properties by as much as 55% versus composites fabricated from surface-treated, unsized IM7 fibers. In addition, by applying these same epoxy-based sizings or coatings onto surface-treated, unsized IM7 fibers it was possible to achieve an 11% increase in the composite interlaminar shear strength compared to composites made from surface-treated, GP-sized IM7 fibers. Work is continuing in this area of research …

The microscopic surface morphology of GaInAsSb grown by organometallic vapor phase epitaxy (OMVPE)on GaSb substrates has been studied by atomic force microscopy. The effects of growth temperature, alloy composition, and substrate misorientation on the step structure were investigated. The competition between thermodynamically driven phase separation and kinetically limited surface diffusion is discussed.

Pulsed x-ray sources have been used in transient structural phenomena investigations for over fifty years; however, until the advent of synchrotrons sources and the development of table-top picosecond lasers, general access to ligh temporal resolution x-ray diffraction was relatively limited. Advances in diffraction techniques, sample excitation schemes, and detector systems, in addition to IncEased access to pulsed sources, have ld tO what is now a diverse and growing array of pulsed-source measurement applications. A survey of time-resolved investigations using pulsed x-ray sources is presented and research opportunities using both present and planned pulsed x-ray sources are discussed.