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We have studied numerically the evolution and decay of axion strings. These global defects decay mainly by axion emission and thus contribute to the cosmological axion energy density. The relative importance of this source relative to misalignment production of axions depends on the spectrum. Radiation spectra for various string loop configurations are presented. They support the contention that the string decay contribution is of the same order of magnitude as the contribution from misalignment.

The cesium powder and pellets inner container is to be performance tested per the criteria specified in Section 4.0 of HNF-2399, ``Design, Fabrication, and Assembly Criteria for Cesium Powder and Pellet Inner Container.`` The test criteria specifies that the inner container be water tight during decontamination of the exterior surface. Three prototypes will be immersed into a pool of water to simulate a water decontamination process.

Spontaneous improvements of plasma confinement during auxiliary heating have been observed in many tokamaks when the q profile has been modified from its normal resistive equilibrium so that q is greater than 1 and the magnetic shear is reduced or reversed in a region near the magnetic axis. The effects on the overall plasma confinement result from the formation in the plasma interior of transport barriers, regions where the thermal and particle transport coefficients are substantially reduced. These internal barriers are sometimes tied to unique magnetic surfaces, such as the surface where the shear reverses. The reduction in transport appears to result from the suppression of turbulence by sheared plasma flow, which has now been measured in TFTR. Extensions of the theory for turbulence suppression show that this underlying paradigm may also explain other regimes of improved core confinement. The excitement generated by these discoveries must be tempered by the realization that transport and stability to pressure-driven MHD instabilities are intimately linked in these plasmas through the bootstrap current and the effect of the resulting current profile on the transport. Thus the development of control tools and strategies is essential if these improved regimes of confinement are to be exploited …

This report documents the results of the second phase of parameter quantification by the flammable gas expert panel. This second phase is focused on the analysis of flammable gas accidents in the Hanford Site double-shell tanks. The first phase of parameter quantification, performed in 1997 was focused on the analysis of Hanford single-shell tanks.

Micro-economic theory began as an attempt to describe, predict and value the demand and supply of consumption goods. Quality was largely ignored at first, but economists have started to address quality within the theory of demand and specifically the question of site quality, which is an important component of land management. This paper demonstrates that hedonic and random utility models emanate from the same utility theoretical foundation, although they make different estimation assumptions. Using a theoretically consistent comparison, both approaches are applied to examine the quality of wilderness areas in the Southeastern US. Data were collected on 4778 visits to 46 trails in 20 different forest areas near the Smoky Mountains. Visitor data came from permits and an independent survey. The authors limited the data set to visitors from within 300 miles of the North Carolina and Tennessee border in order to focus the analysis on single purpose trips. When consistently applied, both models lead to results with similar signs but different magnitudes. Because the two models are equally valid, recreation studies should continue to use both models to value site quality. Further, practitioners should be careful not to make simplifying a priori assumptions which limit the effectiveness of both …

The toroidal Alfvén eigenmodes (TAE) in the Tokamak Fusion Test Reactor [K. Young, et al., Plasma Phys. Controlled Fusion 26, 11 (1984)]deuterium-tritium plasmas are analyzed using the NOVA-K code [C.Z. Cheng, Phys. Reports 211, 1 (1992)]. The theoretical results are compared with the experimental measurements in detail. In most cases, the theory agrees with the observations in terms of mode frequency, mode structure, and mode stability. However, one mode with toroidal mode number n = 2 is observed to be poloidally localized on the high field side of the magnetic axis with a mode frequency substantially below the TAE frequency.

The National Ignition Facility target chamber interior materials and target designs themselves have to be compatible with survival of the final-optics debris shields. To meet the planned maintenance and refinishing rate, the contamination of the debris shields cannot exceed about 1 nm equivalent thickness per shot of total material. This implies that the target mass must be limited to no more than 1 gram and the ablated mass released to the chamber from all other components must not exceed 3 grams. In addition, the targets themselves must either completely vaporize or send any minor amounts of shrapnel towards the chamber waist to prevent excessive cratering of the debris shields. The constraints on the first-wall ablation require that it be louvered to provide passive collection of remobilized contamination, because the expected target debris will remobilize at a rate fast enough to require cleaning every 3 weeks, about three times more frequent than possible with planned robotics. Furthermore, a comparison of ablatants from B{sub 4}C and stainless-steel louvers suggests that remobilization of target debris by x rays will be greater than of the base material in both cases, thereby reducing the performance advantage of clean B{sub 4}C over much-cheaper stainless steel. Neutronics …

The new proton radioactivity {sup 155}Ta has been observed. It was produced via the p4n fusion evaporation channel using a {sup 58}Ni beam on a {sup 102}Pd target. The measured decay properties were: E{sub p} = (1765 {+-} 10) keV and t{sub 1/2} = (12{sub {minus}3}{sup +4}) {micro}s. Using the WKB approximation a spin and parity of J{sup {pi}} = 11/2{sup 2{minus}} and a spectroscopic factor of S{sub p}{sup exp} = 0.58{sub {minus}0.17}{sup +0.22} were determined.

Proton emission half-lives are calculated within the DWBA formalism for {sup 131}Eu and {sup 141}Ho assuming permanent quadruple deformation. The decay rates are consistent with a decay from either [411 3/2] or [413 5/2] Nilsson states for {sup 131}Eu and [523 7/2] Nilsson state for {sup 141}Ho.

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On July 31, 1997, the Environmental Protection Agency proposed a new regulatory program to reduce "regional haze." The proposed program would require the states to develop and implement long-term strategies to attain a congressionally the mandated goal of remedying the impairment of visibility in national parks and wilderness areas resulting from man-made air pollution.

This report discusses primarily, the controversy over encryption concerns what access the government should have to encrypted stored computer data or electronic communications (voice and data, wired and wireless) for law enforcement purposes.