Carbon fiber monoliths manufactured by a novel slurry molding process from isotropic pitch-derived fibers are being developed at ORNL for gas separation and storage applications [1]. Low density (p = 0.2 - 0,3 g/cm3) monoliths have been successfully demonstrated to have an acceptable pressure drop for gas separation applications and are currently being developed for C02/CH4 separations, whereas monoliths with densities in the range p = 0.4 - 0.6 g/cm3 have been "shown to have natural gas storage capacities of >100 VIV at 500 psi pressure and room temperature. Thermal conductivity, as a function of temperature, was measured using the LASER flash, thermal- pulse method. Another approach to minimizing the temperature gradients that develop in a storage bed is to increase the thermal conductivity of the adsorbent carbon. To this end, we have developed hybrid monoliths that contain small fractions of mesophase pitch- derived carbon fibers. Our hybrid monoliths exhibit thermal conductivities in the range 0.2-0.9 W/m.K depending on the blend and density of the monolith. In comparison, a packed bed of granular carbon at comparable density would have a thermal conductivity of approximately 0.1 W/m.K [ 1 ]. The thermal conductivities of several of the hybrid The improved thermal …

Among microinstabilities that may affect the resistance of a Z>>1 plasma in fast Z pinches, are the ion acoustic and the lower hybrid instabilities. We discuss effects of hydrogen ions on these instabilities and find that, by properly adjusting the hydrogen concentration, one can considerably increase the threshold current density for the onset of the instability. In addition to a strong Landau damping on hydrogen ions; there is a collisional stabilizing mechanism related to a collisional friction between the two ion species. Another interesting aspect of the stability analysis is related to the fact that the magnetization (a product of the gyrofrequency and the collisional frequency) of the heavy ions and the hydrogen ions is very different. We discuss possible ways of adding the hydrogen to high-Z material. This is simple in case of gas-puff pinches, where the hydrogen could be added to the main gas before the puffing. For the wire arrays, one might try to saturate th e assembled array by hydrogen prior to the main discharge. One more possibility is using interwoven thin wires of a main component (say, tungsten) and polymer.

Sandia National Laboratories (SNL) has produced limited quantities of fission-produced molybdenum-99 ~%lo) within industry purity specifications using the Cintichem production process. The chemical extraction and purification of `%lo was petiormed using the Hot Cell Facility (HCF) located at Technical Area-V. To thoroughly understand the production process, two series of tests were designed, the first was a series of cold tests using 20 g samples of depleted or low irradiated uranium dioxide powder and the second series was conducted using irradiated targets. In addition, radiation effects tests were petiormed at the SNL Gamma Irradiation Facility (GIF) on chemicals and hardware used in the processing to evaluate the degradation due to the high radiation field expected during the chemical separation. Unique production hardware, fixtures and tools were developed for remote processing of irradiated targets at the HCF.

PharrnaceuticaI houses that produce {sup 99}Tc/{sup 99}Tc generators have on occasion received {sup 99}Mo that contained a black precipitate. Addition of sodium hypochlorite to product bottles prior to shipment prevents precipitate formation, indicating the precipitate is a reduced form of Mo. The radiation effects of the dose from {sup 99}Mo on the product and product bottle have been determined by irradiating simulated {sup 99}Mo product solutions with the {sup 60}Co source at Sandia National Laboratories' Gamma Irradiation Facility (GE). The GIF experiment successfully generated a black precipitate in amounts sufficient for isolation and analysis by infrared and Rrunan spectroscopy. Changes in the pH of the basic {sup 99}Mo product solution during irradiation were monitored by titration. ResuIts of these analyses and the nature of the process that generates the precipitate, a mixture of molybdenum oxides that forms in plastic bottles, but not in glass containers, are discussed.

From 1975 to 1996 the French detonated 140 underground nuclear explosions beneath the atolls of Mururoa and Fangataufa in the South Pacific; from 1965 to 1971 the United States detonated three high yield nuclear tests beneath Amchitka Island in the Aleutian chain. Approximately 800 metric tons of basalt is melted per kiloton of nuclear yield; almost lo7 metric tons of basalt were melted in these tests. Long-lived and toxic radionuclides are partitioned into the melt glass at the time of explosion and are released by dissolution with seawater under saturated conditions. A glass dissolution model predicts that nuclear melt glasses at these sites will dissolve in lo6 to lo7 yea

This workshop's focus is on considering ways for improving the proton beam polarization that the AGS delivers to the RHIC. This talk attempts to review the first decade of AGS polarization--the 1980's; to briefly describe some aspects of the machine situation, the depolarization avoidance strategies employed and the success achieved in AGS from the perspective of one of those involved.

Reactive spreading, in which a chemically active element is added to promote wetting of noble metals on nonmetallic materials, is evaluated mechanistically. Theories for the energetics and kinetics of the steps involved in spreading are outlined to permit comparison to the steps in the compound formation that typically accompanies reactive wetting. These include: fluid flow, active metal adsorption, including nonequilibrium effects, and triple line ridging. They can all be faster than compound nucleation under certain conditions. This analysis plus assessment of recently reported experiments on metal/ceramic systems lead to a focus on those conditions under which spreading proceeds ahead of the actual formation of a new phase at the interface. This scenario may be more typical than commonly believed, and perhaps is the most effective situation leading to enhanced spreading. A rationale for the slow spreading rates plus the pervasive variability and hysteresis observed during high temperature wetting also emerges.

Previous algorithms for view-dependent level of detail provide local mesh refinements either at the finest granularity or at a fixed, coarse granularity. The former provides triangle-level adaptation, often at the expense of heavy CPU usage and low triangle rendering throughput; the latter improves CPU usage and rendering throughput by operating on groups of triangles. We present a new multiresolution hierarchy and associated algorithms that provide adaptive granularity. This multi-grained hierarchy allows independent control of the number of hierarchy nodes processed on the CPU and the number of triangles to be rendered on the GPU. We employ a seamless texture atlas style of geometry image as a GPU-friendly data organization, enabling efficient rendering and GPU-based stitching of patch borders. We demonstrate our approach on both large triangle meshes and terrains with up to billions of vertices.

This article reports the formation of resonance cavities within graded photonic super-crystals (GPSCs) with unit cells formed via a near-uniform central region with eight side graded regions.

Article describes how data-driven decision-making (DDDM) technologies are increasingly being utilized, aiming to enhance education quality. Authors assert that this paper examines articles that explore the implementation of DDDM technologies and their effects on education quality.

Article describes how a novel Eu(tta)3([4,4′-(t-bu)2-2,2′-bpy)] complex (tta-thenoyltrifluoroacetone), a ratiometric luminescent-based optical sensor for the quantitative determination of aluminum ion, is synthesized and characterized using XRD and 1H NMR. The sensor reported here is tested for 11 common cations and shows no interference on sensitivity. According to the authors, this is the first known Eu-based luminescence sensor that successfully exhibited the ability to detect aluminum ions in ppb levels in aqueous environments.