The fact that inclusively produced hyperons are produced with significant polarization was first discovered at Fermilab about seventeen years ago. This and subsequent experiments showed that [Lambda][degree] were produced polarized while [bar [Lambda] [degree]] had no polarization in the same kinematical region. This set the stage for many experiments which showed that most hyperons are produced polarized. Recent Fermilab experiments have showed that this phenomena is even more complex than previously thought and theoretical understanding is still lacking. Nevertheless polarized hyperon beams have been an extremely useful experimental tool in measuring hyperon magnetic moments and hyperon [beta]-decay. Recently, hyperon radiative decays have been studied and magnetic moment precession of channeled particles in bent crystals has been observed.

It is well known that beamstrahlung and bremsstrahlung take place over a finite formation zone distance. If something disturbs the electron during this time, the emission can be suppressed. In this paper, we examine the Landau-Pomeranchuk-Migdal (LPM) effect and other LPM-like effects, such as the longitudinal density (di- electric) suppression and EM field suppression of beamstrahlungand bremsstrahlungin e[sup +]e[sup -] linear colliders. We show that while the LPM effect and the density effect are not sufficient in suppressing these radiations, the strong EM field of the opposing beam does help to suppress bremsstrahlung.

The Fermilab 200-MeV Linac has been in operation for nearly 22 years as a proton injector to the Booster synchrotron. It presently accelerates H[sup [minus]] ions to 200 MeV for charge-exchange injection into the Booster and to 66 MeV for the production of neutrons at the Neutron Therapy Facility. The beam intensity is typically 35 mA with pulse widths of 30 [mu]sec for the Booster for high energy physics and 57 [mu]sec for NTF at a maximum of 15 pulses per sec. During a typical physics run of nine to twelve months, beam is available for greater than 98% of the scheduled time. The Linac history, operation, tuning, stability and reliability will be discussed.

Nanometer-scale atom clusters (with average diameters below 20 nm) of a variety of materials, including both metals and ceramics, have been synthesized by precursor evaporation and condensation in high-purity gases. The gas-entrained clusters can be collected and subsequently consolidated in situ under ultrahigh vacuum or other controlled atmosphere conditions to create bulk nanophase materials. These ultrafine-grained materials have properties that are often significantly different and considerably improved relative to those of their coarser-grained counterparts. The observed property changes relate to both their small grain sizes and the large percentage of their atoms in grain boundary environments. Since it is becoming apparent that their properties can be engineered during gas-phase synthesis and subsequent processing, nanophase materials assembled from atom clusters should have significant potential for technological development in a variety of applications. Some of the recent research on nanophase materials is reviewed.

There is an increasing industry interest in integrated gas turbine combined cycle plants in which coal gasifiers provide the fuel for the gas turbines. Some gasifier plant designs, including the air-blown processes, some integrated oxygen blown processes and some oxygen-blown processes followed by heavy moisturization, produce fuel gases which have lower heating values ranging from 130 to below 100 BTU/scf for which there is little gas turbine combustion experience. This program has the objectives to: Parametrically determine the effects of moisture, nitrogen and carbon dioxide as diluents so that the combustion characteristics of many varieties of gasification product gases can be reasonably predicted without physically testing each specific gas composition; determine emissions characteristics including NO{sub x}, CO, levels etc. associated with each of the diluents; operate with two syngas compositions; DOE chosen air-blown and integrated oxygen-blown, to confirm that the combustion characteristics are in line with predictions; determine if ``logical`` refinements to the fuel nozzle will yield improved performance for LBTU fuels; determine the conversion rate of ammonia to NO{sub x}; determine the effects of methane inclusion in the fuel.

The modified finite element procedure for underwater shock analysis decomposes the total pressure field into the incident, reflected and radiated pressure. The incident pressure is calculated by using a closed form solution. The reflected and radiated pressure are calculated in two separate finite element analyses. Artificial damping is added in the finite element analyses. Since these two pressures are generated from the fluid-structure interface and mostly propagate away from the interface, the artificial damping has no significant effect on the result. The modified finite element procedure was developed using a displacement formulated finite element to model the fluid region. In the paper, a pressure formulated finite element is used to model the fluid region which has a potential of saving 90 percent of the computer time. In doing so, the reflected and radiated pressure are calculated in one analysis which greatly simplifies the analysis procedure and saves more computer time. Two verification examples are given.

If a main steam line from a pressurized water reactor (PWR) steam generator were to rupture, the effect would be a depressurization of the secondary side and a consequential overcooling transient on the primary side. Analyses must accurately predict the effects of the rapid cooldown of the reactor vessel coolant on positive nuclear-kinetic reactivity feedback to the core plus thermal shock to the reactor vessel and other primary system components. Many early studies of the steam line break (SLB) transient made extremely conservative assumptions to maximize the primary to secondary heat transfer which in turn maximized the reactor vessel cooldown rate. Among the more significant of these assumptions was that flow from the break was pure steam and that the tube bundle remained covered until the secondary mass inventory was significantly reduced. The Model F commercial PWR steam generator testing performed in the Model Boiler No. 2 (MB-2) facility located at the Westinghouse Engineering Test Facility in Tampa, Florida provided data to better qualify the actual variation in these key parameters. A conclusion of this analysis is that the MB-2 steam line break data base is accurate and of sufficient detail to provide a valuable basis for making comparisons relative …

We present a scheme for polarized proton operation in the RHIC collider complex. For low energies the partial siberian snake project in the AGS is reviewed. As the energy is increased the difficulties of preserving the polarization also increases. A plan for preserving the polarization at high energies in RHIC using two Siberian Snakes is discussed. Spin rotators will be used around the collision points so that the helicity can be varied.

It is well known that charged particles emit bremsstrahlung radiation when they are accelerated. Classical electron bremsstrahlung occurs when a photon is emitted by an electron accelerated in the field of a nucleus. The bremsstrahlung process also occurs in the scattering of nucleons, for which it is the lowest energy inelastic process that can occur. Like electron bremsstrahlung, nucleon-nucleon bremsstrahlung also requires the exchange of a virtual particle to conserve energy and momentum. In electron bremsstrahlung a virtual photon is exchanged but with two nucleons a meson can be exchanged. Unlike electron bremsstrahlung, in nucleon-nucleon bremsstrahlung the photon can originate from the exchanged meson. This exchange contribution has been shown in calculations to be a significant fraction of bremsstrahlung events. Thus bremsstrahlung serves as a probe of exchange currents in the nucleon-nucleon interaction. Because of a lack of a free neutron target or an intense neutron beam, few measurements of neutron-proton bremsstrahlung exist, each having poor statistical accuracy and poor energy resolution. The white neutron source at the Weapons Neutron Research (WNR) target area at the Los Alamos Meson Physics Facility (LAMPF) produces neutrons with energies from below 50 to above 400 MeV. Using time-of-flight techniques and a liquid hydrogen …

A brief overview of the status of lattice QCD is given, with emphasis on topics relevant to phenomenology. The calculation of the light quark spectrum, the lattice prediction of {alpha} {sub {ovr MS}} (M {sub Z}), and the calculation of f{sub B} are discussed. 3 figs., 3 tabs., 40 refs.

This study, sponsored by the New Production Reactor (NPR) Program through the Los Alamos NPR Safety Project Office, is part of the body of severe-accident review information being developed to support the safety review of the New Production Heavy-Water Reactor (NP-HWR). The NP-HWR safety study of severe beyond-design-basis events concerns two issues related to in-vessel, sudden-energy sources: wet-core recriticality and molten-fuel-and-coolant interaction (MFCI). The configuration that will lead to recriticality and MFCI is determined by the mode and coherency of the fuel-target disruption and water contact during the accident progression. The mode and coherency are, in turn, governed by the thermal-hydraulic conditions in the assembly channel and the fuel heatup rate after the assembly channels have dried out. The results of the analysis, presented for the transients out to the time of incipient fuel melt, describe the dominant features of the transients for the two severe events. The conclusions summarize what we have learned about the controlling mechanisms and important parameters for the conditions leading up to fuel melt, identify important safety review information that may be relevant to the final design, and suggest actions needed to conduct an adequate safety review of relevant aspects of the NP-HWR.

Advances in theory and computations related to the reversed field pinch (RFP) are presented. These are: (1) the effect of the dynamo on thermal transport; (2) a theory of ion heating due to dynamo fluctuations; (3) studies of active and passive feedback schemes for controlling dynamo fluctuations; and (4) an analytic model for coupled g-mode and rippling turbulence in the RFP edge.

Knowledge of fabrication induced residual stresses in the fiber and matrix of advanced engineering composites is important as these stresses can greatly influence the mechanical properties of these composites. In this paper, the application of neutron diffraction technology to the determination of thermal residual strains in the constituents of composites (from which stresses can be calculated) is discussed. Experimental determination of temperature dependent strain in the fiber and matrix of three composites compare favorably with the results of analytical and finite element methods used to predict strain. These composites (two ceramic matrix and one metal matrix) are materials of interest to a variety of industries. In this paper, the benefit of applying a National Laboratory developed technology to a problem of interest to industry, is shown.

Collisions between two heavy nuclei produce a diverse spectrum of reaction modes which is much wider than that observed in light ion studies. For the latter case, two processes are observed: direct reactions and compound nucleus formation. Heavy ion reaction studies on the other hand have identified additional processes such as deep-inelastic scattering, incomplete fusion and quasi-fission reactions. While the boundaries between the various processes are usually not well defined, it is generally accepted that with increasing overlap of the two nuclei the interaction evolves from distant collisions where only elastic scattering and Coulomb excitation processes occur, through grazing-type collisions associated with quasi-elastic reactions to deep-inelastic and fusion-fission processes requiring a substantial nuclear overlap. Varying the bombarding energy is a convenient way to change the overlap of the two nuclei. Measurements of excitation functions can thus probe the onset and the interplay of the various reaction modes. Experiments at bombarding energies in the vicinity of the Coulomb barrier are particularly suited for comparisons with theoretical predictions since the small number of degrees of freedom involved in the interaction greatly simplifies the calculations. In the first part of this contribution a short overview is given on the status of heavy ion …

We present jet rates in hadronic decays of Z{sup 0} bosons measured by the SLD experiment at SLAC. The data are analyzed in terms of the JADE and recently proposed Durham algorithms, and are found to be in agreement with similar measurements by the LEP experiments, and also with the predictions of perturbative QCD and fragmentation Monte Carlo models of hadron production. After correction for hadronization effects the 2, 3 and 4-jet rates are well described by {Omicron}({alpha}{sub s}{sup 2}) perturbative QCD calculations. From fits to the differential 2-jet distribution the strong coupling {alpha}{sub s}(M{sub Z}) is measured to be {alpha}{sub s}(M{sub Z}) = 0.119 {plus_minus} 0.002(stat.) {plus_minus} 0.003(exp.syst.) {plus_minus} 0.014(theory) (preliminary). The largest contribution to the error arises from the theoretical uncertainty in choosing the QCD renormalization scale.

Iowa Power and Dairyland Power have formed a partnership and entered into an agreement with the United States Department of Energy (DOE) to repower a mothballed electric generating facility using Pressurized Circulating Fluidized Bed (PCFB) combustion technology. The project is the first commercial application of PCFB technology. The project includes the refurbishment of an existing steam turbine cycle, installation of the PCFB and gas turbine, and a two year operating period to demonstrate the technology. The repowered unit is expected to be rated at 80 MW. The plant is scheduled to begin operation in 1996. Process systems are described.

Dilute calcium chloride brine solution was found to be effective in the solubilization of toxic heavy metals and long half-life radionuclides (Th-230, Ra-226 and Pb-210) from uranium ores and mill tailings. The recovery of heavy metals and radionuclides from uranium mill tailing effluents was studied with calcium alginate beads. The maximum cadmium and zinc uptakes by calcium alginate beads were determined to be 2.8 {times} 10{sup {minus}3} and 2.3 {times} 10{sup {minus}3} mol/dry weight of alginate. The kinetic values, V{sub m} and K, were calculated for uranium uptake by calcium alginate to be 96.2 mg/l/s and 0.125 g/l, respectively.

Most previous analysis on the effects of geomagnetically induced currents (GIC) on electric utility systems has steady-state phenomena, with the main interest in the generator step-up transformer and the off-site power system. This paper begins to investigate the possible effects that a GIC event might have on the power plant itself, by examining the harmonic distortion that could exist at various voltage levels in the on-site distribution system.

Wave packet calculations modeling vibrational predissociation in X{sub 2}BC(v{sup {prime}}) van der Waals clusters are discussed. A model involving three active degrees of freedom is used. Cluster lifetimes and BC vibrational product distributions are obtained, and compared with available experimental results for He{sub 2}Cl{sub 2}, and Ne{sub 2}Cl{sub 2}. Some preliminary results for He{sub 2}I{sub 2} and Ne{sub 2}I{sub 2} are also discussed. Mechanistic issues, including the role of direct versus sequential mechanisms in leading to the production of 2X {plus} BC are addressed, as well as the role of intramolecular vibrational relaxation (IVR). Higher dimension extensions of the model are suggested. 3 figs., 3 tabs., 22 refs.

The method of Bayesian inference is reexamined for its applicability and for the required underlying assumptions in obtaining and using prior probability estimates. Two different approaches are suggested to determine the first-stage priors in the two-stage Bayesian analysis which avoid certain assumptions required for other techniques. In the first scheme, the prior is obtained through a true frequency based distribution generated at selected intervals utilizing actual sampling of the failure rate distributions. The population variability distribution is generated as the weighed average of the frequency distributions. The second method is based on a non-parametric Bayesian approach using the Maximum Entropy Principle. Specific features such as integral properties or selected parameters of prior distributions may be obtained with minimal assumptions. It is indicated how various quantiles may also be generated with a least square technique.

Thin foils of Zircaloy-4 were irradiated with 350 KeV {sup 40}Ar ions in the dual ion beam/HVEM facility at Argonne National Laboratory at 300--650 K. The irradiation-induced amorphization of the intermetallic precipitates Zr (Cr; Fe){sub 2} and Zr{sub 2} (Ni, Fe) was studied in-situ. For Zr (Cr, Fe){sub 2} precipitates the dose-to-amorphization was found to increase exponentially with temperature, with a critical temperature of about 650 K. The amorphization morphology was shown to be homogeneous, with no preferential site for nucleation, in contrast to neutron-irradiation amorphization which started at the precipitate-matrix interface. For Zr{sub 2} (Ni,Fe) precipitates it was found that amorphization occurred at 550 and 600 K, whereas in neutron irradiation no amorphization has been observed at those temperatures. The results are discussed in context of previous neutron and electron irradiations and likely amorphization mechanisms are proposed.

Radioactive nuclear beams (RNBs) offer exciting new research opportunities in fields as diverse as nuclear structure, nuclear reactions, astrophysics atomic, materials, and applied science. Their realization in new accelerator complexes also offers important technical challenges. Some of the nuclear physics possibilities afforded by RNBs, with emphasis on low spin nuclear structure, are discussed, accompanied by an outline of the ISL initiative and its status.

Surface modification can improve materials for structural, tribological, and corrosion applications. Excimer laser light has been shown to provide a rapid means of modifying surfaces through heat treating, surface zone refining, and mixing. Laser pulses at modest power levels can easily melt the surfaces of many materials. Mixing within the molten layer or with the gas ambient may occur, if thermodynamically allowed, followed by rapid solidification. The high temperatures allow the system to overcome kinetic barriers found in some ion mixing experiments. Alternatively, surface zone refinement may result from repeated melting-solidification cycles. Ultraviolet laser light couples energy efficiently to the surface of metallic and ceramic materials. The nature of the modification that follows depends on the properties of the surface and substrate materials. Alloying from both gas and predeposited layer sources has been observed in metals, semiconductors, and ceramics as has surface enrichment of Cr by zone refinement of stainless steel. Rapid solidification after melting often results in the formation of nonequilibrium phases, including amorphous materials. Improved surface properties, including tribology and corrosion resistance, are observed in these materials.

We report the results of temperature-dependent optical Kerr effect experiments for formamide (FA) and N-methylformamide (NMF). Binary solutions of FA and NMF were also studied with water, acetonitrile, and N,N-dimethylformamide as cosolvents.