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Gas desorption and electron emission coefficients were measured for 1 MeV potassium ions incident on stainless steel at grazing angles (between 80 and 88 degrees from normal incidence) using a new gas-electron source diagnostic (GESD). Issues addressed in design and commissioning of the GESD include effects from backscattering of ions at the surface, space-charge limited emission current, and reproducibility of desorption measurements. We find that electron emission coefficients {gamma}{sub e} scale as 1/cos({theta}) up to angles of 86 degrees, where {gamma}{sub e} = 90. Nearer grazing incidence, {gamma}{sub e} is reduced below the 1/cos({theta}) scaling by nuclear scattering of ions through large angles, reaching {gamma}{sub e} = 135 at 88 degrees. Electrons were emitted with a measured temperature of {approx}30 eV. Gas desorption coefficients {gamma}{sub 0} were much larger, of order {gamma}{sub 0} = 10{sub 4}. They also varied with angle, but much more slowly than 1/cos({theta}). From this we conclude that the desorption was not entirely from adsorbed layers of gas on the surface. Two mitigation techniques were investigated: rough surfaces reduced electron emission by a factor of ten and gas desorption by a factor of two; a mild bake to {approx}220 degrees had no effect on electron emission, …

The F-Canyon Facility was constructed in the early 1950's for the separation and recovery of 239Pu, 237Np and 238U from irradiated natural or depleted uranium targets and fuel rods using the PUREX (Plutonium - Uranium Extraction) process. In the PUREX process, the irradiated target or fuel slugs are received from the reactor areas of the Receiving Basin for Offsite Fuels, charged to the dissolvers and dissolved in nitric acid. The resulting solution contains primarily uranium-238 and smaller amounts of plutonium, uranium-235, and fission products. The primary operations conducted in F-Canyon include the separation and recovery of Pu-239 and U-238 from irradiated materials in the stabilization of plutonium residues. Since 1995, the F-Canyon Complex has been operating to stabilize ''at risk'' nuclear materials and spent fuel from throughout the DOE complex. That mission is complete. Since the last low level waste characterization, the F-Canyon has been implementing the PUREX Operations Suspension Plan and the Deactivation Project Plan.

NMR-based biosensors that utilize laser-polarized xenon offer potential advantages beyond current sensing technologies. These advantages include the capacity to simultaneously detect multiple analytes, the applicability to in vivo spectroscopy and imaging, and the possibility of remote amplified detection. Here we present a detailed NMR characterization of the binding of a biotin-derivatized caged-xenon sensor to avidin. Binding of functionalized xenon to avidin leads to a change in the chemical shift of the encapsulated xenon in addition to a broadening of the resonance, both of which serve as NMR markers of ligand-target interaction. A control experiment in which the biotin-binding site of avidin was blocked with native biotin showed no such spectral changes, confirming that only specific binding, rather than nonspecific contact, between avidin and functionalized xenon leads to the effects on the xenon NMR spectrum. The exchange rate of xenon (between solution and cage) and the xenon spin-lattice relaxation rate were not changed significantly upon binding. We describe two methods for enhancing the signal from functionalized xenon by exploiting the laser-polarized xenon magnetization reservoir. We also show that the xenon chemical shifts are distinct for xenon encapsulated in different diastereomeric cage molecules. This demonstrates the potential for tuning the encapsulated xenon …

The majority of US commercial floor space is cooled by rooftop HVAC units (RTU's). RTU popularity derives chiefly from their low initial cost and relative ease of service access without disturbing building occupants. Unfortunately, current RTU's are inherently inefficient due to a combination of characteristics that unnecessarily increase cooling loads and energy use. Existing RTU's in the U.S. consume an estimated 2.4 quads annually. Inefficient RTU's create an estimated 3.5% of U.S. CO{sub 2} emissions, thus contributing significantly to global warming. Also, RTU's often fail to maintain adequate ventilation air and air filtration. This project was developed to evaluate the feasibility of a radically new ''HyPak'' RTU design that significantly and cost-effectively increases RTU performance and delivered air quality. The objective of the HyPak Project was to design, develop and test a hydronic RTU that provides a quantum improvement over conventional RTU performance. Our proposal targeted 60% and 50% reduction in electrical energy use by the HyPak RTU for dry and humid climates, respectively, when compared with a conventional unit.

Two and three dimensional assemblies of colloidal nanocrystals (NCs) have been of great interest during recent years [1-3]. While size-dependent optical and electronic properties of isolated particles are particularly important for fundamental research, studies of their ordered assemblies provide a transition path to the engineering of materials and devices for future practical applications. Assemblies of NCs of different materials, such as semiconductors, metals and metal oxides, have been reported in the literature during recent years [4-7]. However, perfect, crystallographic-ordered assemblies of colloidal NCs or colloidal superlattices (SLs) have been observed so far only using transmission (TEM) and scanning electron microscopy (SEM) in a very small scale of a few hundred nanometers, while macroscopic characterization and device application demonstrations have been performed mainly on amorphous, randomly packed powders of NCs [8, 9]. To make SLs available for traditional methods of characterization, they should be obtained in a sufficiently large size. For colloidal NCs soluble in variety of solvents, simple growth from solution seems to be an appropriate choice to produce SLs. In solution, NCs act as large molecules that, as shown previously [1, 8], can form nanoscale ordered assemblies by the classical Frank-Cabrerra mechanism [10] of crystal growth. It is, however, …

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Growing interest and exploration dollars within the geothermal sector have paved the way for increasingly sophisticated suites of geophysical and geochemical tools and methodologies. The efforts to characterize and assess known geothermal fields and find new, previously unknown resources has been aided by the advent of higher spatial resolution airborne geophysics (e.g. aeromagnetics), development of new seismic processing techniques, and the genesis of modern multi-dimensional fluid flow and structural modeling algorithms, just to name a few. One of the newest techniques on the scene, is hyperspectral imaging. Really an optical analytical geochemical tool, hyperspectral imagers (or imaging spectrometers as they are also called), are generally flown at medium to high altitudes aboard mid-sized aircraft and much in the same way more familiar geophysics are flown. The hyperspectral data records a continuous spatial record of the earth's surface, as well as measuring a continuous spectral record of reflected sunlight or emitted thermal radiation. This high fidelity, uninterrupted spatial and spectral record allows for accurate material distribution mapping and quantitative identification at the pixel to sub-pixel level. In volcanic/geothermal regions, this capability translates to synoptic, high spatial resolution, large-area mineral maps generated at time scales conducive to both the faster pace of …

The Graphite Isotope Ratio Method (GIRM) is a technique used to estimate the total plutonium production in a graphite-moderated reactor. The cumulative plutonium production in that reactor can be accurately determined by measuring neutron irradiation induced isotopic ratio changes in certain impurity elements within the graphite moderator. The method does not require detailed knowledge of a reactor's operating history, although that knowledge can decrease the uncertainty of the production estimate. The basic premise of the Graphite Isotope Ratio Method is that the fluence in non-fuel core components is directly related to the cumulative plutonium production in the nuclear fuel.

The vapor deposition methods of planar magnetron sputtering and electron-beam evaporation are used to synthesize materials with nano structured morphological features that have ultra-high surface areas with continuous open porosity at the nano scale. These nano structured membranes are used in a variety of fuel cells to provide electrode and catalytic functions. Specifically, stand alone and composite nickel electrodes for use in thin film solid-oxide, and molten carbonate fuel cells are formed by sputter deposition and electron bean evaporation, respectively. Also, a potentially high-performance catalyst material for the direct reformation of hydrocarbon fuels at low temperatures is deposited as a nano structure by the reactive sputtering of a copper-zinc alloy using a partial pressure of oxygen at an elevated substrate temperature.

Lawrence Berkeley Laboratory is working to improve energy efficiency in high-tech facilities, i.e., laboratories, data centers, and clean rooms. With their high ventilation requirements and correspondingly high process loads, 7x24 operation, and importance to the overall economy, these types of facilities offer important (and often under-exploited) potential for energy savings. In California alone, two large electric power plants could be avoided with the widespread adoption of measures to improve energy efficiency in this arena, saving half a billion dollars per year for facility owners. To help identify specific promising opportunities, the California Energy Commission sponsored the development of technology research ''Roadmaps'' for clean rooms and laboratories (in 2002) and data centers (in 2003). These were developed with industry participation and provided dozens of specific recommendations. The balance of this article focuses on the case of clean rooms.