Determining the concentration of gallium in plutonium metal is imperative in manufacturing nuclear weapons. X-ray fluorescence (XRF) is an effective method used to quantify the gallium content in plutonium; however, the sample and specimen preparation methods currently employed could be improved from a time and safety standpoint. Recently, a dried residue specimen preparation method was developed as an alternative to the established aqueous approach. The method currently certified to prepare plutonium for gallium analysis by XRF involves dissolving the sample and removing the plutonium with ion exchange chromatography. The gallium remaining in solution is then analyzed. This method has been thoroughly developed, and relative accuracy and precision values less than 1% can be achieved. However, this process is time consuming, and the specimen solution is radioactive due to the presence of residual plutonium and trace americium. Thus, an alternate process was developed to avoid these issues in which the plutonium solution is cast in {mu}L spots on Mylar XRF film, dried, and sealed inside a sample cell for analysis. This specimen preparation method is considerably faster and also safer than the solution process. Previous studies have demonstrated that a very linear calibration can be obtained from dried residue standards. In …

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We have implemented a suite of chemical transport and fate models that provide diagnostic information about the behavior of ethanol (denoted EtOH) and other fuel-related chemicals released to the environment. Our principal focus is on the impacts to water resources, as this has been one of the key issues facing the introduction of new fuels and additives. We present analyses comparing the transport and fate of EtOH, methyl tertiary butyl ether (MTBE), and 2,2,4 trimethyl pentane (TMP) for the following cases (1) discharges to stratified lakes, subsurface release in a surficial soil, (3) cross-media transfer from air to ground water, and (4) fate in a regional landscape. These compounds have significantly different properties that directly influence their behavior in the environment. EtOH, for example, has a low Henry's law constant, which means that it preferentially partitions to the water phase instead of air. An advantageous characteristic of EtOH is its rapid biodegradation rate in water; unlike MTBE or TMP, which degrade slowly. As a consequence, EtOH does not pose a significant risk to water resources. Preliminary health-protective limits for EtOH in drinking water suggest that routine releases to the environment will not result in levels that threaten human health.

Purpose: To assess the {sup 11}B(p, {alpha}){sup 8}Be* nuclear reaction for quantitatively mapping the in-vivo sub-cellular distribution of boron within gliosarcoma tumors treated with boronated neutron capture therapy agent (NCTA) analogs. Materials and Methods: Intracranial tumors were produced in Fisher 344 rats using a 9L gliosarcoma model. Fourteen days later, the majority of rats were treated with f-boronophenylalanine and sacrificed 30 or 180 minutes after intravenous injection. Freeze dried tumor cryosections were imaged using the {sup 11}B(p, {alpha}){sup 8}Be* nuclear reaction and proton microbeams obtained from the nuclear microprobe at Lawrence Livermore National Laboratory. Results/Discussion: With{sup 11}B(p, {alpha}){sup 8}Be* analysis, {sup 11}B distributions within cells can be quantitatively imaged with spatial resolutions down to 1.5 {micro}m, minimum detection limits of 0.8 mg/kg and acquisition times of several hours. These capabilities offer advantages over alpha track autoradiography, electron energy loss spectroscopy and secondary ion mass spectrometry (SIMS) for 'B quantitation in tissues. However, the spatial resolution, multi-isotope capability and analysis times achieved with SIMS are superior to those achieved with {sup 11}B(p, {alpha}){sup 8}Be* analysis. Conclusions: When accuracy in quantitation is crucial, the assessing the microdistribution of {sup 11}B. {sup 11}B(p, {alpha}){sup 8}Be* reaction is well suited for Otherwise, SIMS may …

In this study, we present nano-scale investigations of point defect dynamics in perovskite oxides by correlated atomic resolution high angle annular dark field imaging (HAADF) and electron energy loss spectroscopy (EELS). The point defect dynamics and interactions during in-situ reduction in the microscope column are analyzed. In particular, oxygen vacancy creation, diffusion and clustering are studied, as oxygen vacancies comprise the majority of the point defects present in these perovskite oxide systems [1]. The results have been acquired using the JEOL2010F, a STEM/TEM, equipped with a 200 keV field emission gun, a high angle annular dark field detector and a post column Gatan imaging filter (GIF). The combination of the Z-contrast and EELS techniques [2] allows us to obtain direct images (spatial resolution of 2 {angstrom}) of the atomic structure and to correlate this information with the atomically resolved EELS information (3s acquisition time, 1.2 eV energy resolution). In-situ heating of the material is performed in a Gatan double tilt holder with a temperature range of 300 K-773 K at an oxygen partial pressure of P{sub O{sub 2}} = 5 * 10{sup -8} Pa.

Alloy 22 (UNS N06022) was proposed for the corrosion resistant outer barrier of a two-layer waste package container for nuclear waste at the potential repository site at Yucca Mountain in Nevada (USA). A testing program is underway to characterize and quantify three main modes of corrosion that may occur at the site. Current results show that the containers would perform well under general corrosion, localized corrosion and environmentally assisted cracking (EAC). For example, the general corrosion rate is expected to be below 100 nm/year and the container is predicted to be outside the range of potential for localized corrosion and environmentally assisted cracking.

When the stadium-size, National Ignition Facility (NIF) is fully operational at the Lawrence Livermore National Laboratory (LLNL), its 192 laser beams will deliver 1.8 megajoules (500 terawatts) of energy onto a target to create extremely high temperatures and pressures for inertial confinement fusion research. Due to the high-energy-physics requirements of the NIF optical components, the optics and their surrounding beampath as well as the supporting utility systems must be fabricated, cleaned, assembled, and commissioned for precision cleanliness. This paper will provide an overview of the NIF cleanliness requirements, the clean construction protocol (CCP) specifications for the beampath and clean utilities, and techniques for verifying the CCP specifications. The NIF cleanliness requirements define limits for molecular and particulate contamination; the goal of these limits is to prevent contamination of the optical components. To prevent laser-induced damage and poor laser quality in the optical components, requirements for cleaning, assembly, installation, and commissioning in terms of particle and nonvolatile residue (NVR) levels are defined. The requirements in the interior of the beampath are parts-per-billion airborne molecular contamination (AMC) and Class 1 particulate levels. To achieve the cleanliness requirements for the beampath interior, a graded CCP approach is used as the NIF beampath and …

Communication-driven scheduling is known to be an effective technique to improve the performance of parallel workloads in time-sharing clusters. Although several such coscheduling algorithms have been proposed, to our knowledge, none of these techniques have been adopted in commercial systems. We believe this is primarily because many of these algorithms has not been exhaustively tested on real systems in presence of mixed workloads, and hence, have not been demonstrated as a favorable alternative to the traditional, batch scheduling. Moreover, practical issues like lack of a methodological approach to efficiently implement, port or reuse the necessary software have dissuaded designers from including coscheduling as a feature in the mainstream system software layer. In this paper, we attempt to fill these crucial voids by addressing several key issues. First, we propose a generic framework for deploying coscheduling techniques by providing a reusable and dynamically loadable kernel module. Second, we implement three prior dynamic coscheduling algorithms (Dynamic coscheduling (DCS), Spin Block (SB) and Periodic Boost (PB)) and a new coscheduling technique, called Co-ordinated coscheduling (CC), using the above framework. Then, we demonstrate the effectiveness of these strategies by implementing a prototype on a Myrinet connected 16-node Linux cluster that uses industry standard Virtual …

We report a systematic neutron diffraction study on the coexistence of long-range magnetic order and superconductivity in heavy fermion compounds CeRhl-,M,Ins (M=Ir,Co). In addition to the incommensurate antiferromagnetic component in pure CeRhIn5, new type of antiferromagnetic component is found to concur with appearance of superconductivity in the Ir and Co alloy series. There is no detectable effect of the superconducting transition on magnetic order parameters. We compare those results with similar studies we performed on CeRhIn:, under pressure. We also discuss possible theoretical scenarios.

Multi-pulse radiographic accelerators, such as the DARHT-II facility under construction at Los Alamos National Laboratory, generate X-rays by striking a solid, high-Z ''bremsstrahlung converter target'' with a tightly focused, high-current, relativistic electron beam. In the process, the converter target is heated to a plasma state and significant thermal expansion can occur during the interval between pulses, depleting the beam focus region of target material and reducing the X-ray output. Beam scatter and various other technical constraints prevent using thicker targets, moving the electron beam to a fresh target region, or moving fresh target material into a fixed beam location. The remaining possibility is to optimize the choice of target material to maximize the effective heat capacity while maintaining dose and minimizing scatter. A kinematic model of a ''composite target'' of high-Z material in a low-Z matrix is presented here as a candidate for such an optimized target. The thermal destruction of the target cannot be avoided but can be slowed sufficiently to maintain the necessary output dose. Methods of manufacturing such targets, and their radiographic performance, are being tested at the ETA-II accelerator facility at Lawrence Livermore National Laboratory.

To better understand the flow mechanisms that contribute to the aerodynamic drag of heavy vehicles, unsteady large-eddy simulations are performed to model the wake of a truncated trailer geometry above a no-slip surface. The truncation of the heavy vehicle trailer is done to reduce the computational time needed to perform the simulations. Both unsteady and time-averaged results are presented from these simulations for two grids. A comparison of velocity fields with those obtained from a wind tunnel study demonstrate that there is a distinct di.erence in the separated wake of the experimental and computational results, perhaps indicating the influence of the geometry simplification, turbulence model, boundary conditions, or other aspects of the chosen numerical approach.

A wide array of field observations, in situ testing, and rock and water sampling (and subsequent analyses) within the unsaturated zone of Yucca Mountain demonstrate the importance of fractures to flow and transport in the welded tuffs. The abundance of fractures and the spatial variability in their hydraulic properties, along with the heterogeneity within lithologic formations, make evaluation of unsaturated processes occurring within the potential repository horizon complex. Fracture mapping and field testing show that fractures are well connected, yet considerable variation is seen within and between units comprising the potential repository horizon with regard to fracture trace length, spacing, permeability, and capillarity. These variations have important implications for the distribution and movement of water and solutes through the unsaturated zone. Numerical models designed to assess such phenomena as unsaturated flow, transport, and coupled thermal-hydrological processes each require their own conceptual model for fracture networks, in order to identify the subset of all fractures that is relevant to the particular study. We evaluate several process-dependent conceptual models for fractures and identify the relevant fracture subsets related to these processes.

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A family of high-field dipoles is being developed at Texas A&M University, as part of the program to improve the cost-effectiveness of superconducting magnet technology for future hadron colliders. The TAMU technology employs stress management, flux-plate control of persistent-current multipoles, conductor optimization using mixed-strand cable, and metal-filled bladders to provide pre-load and surface compliance. Construction details and status of the latest model dipole will be presented.

Direct aqueous mineral carbonation has been investigated as a process to convert gaseous CO{sub 2} into a geologically stable, solid final form. The process utilizes a solution of sodium bicarbonate (NaHCO{sub 3}), sodium chloride (NaCl), and water, mixed with a mineral reactant, such as olivine (Mg{sub 2}SiO{sub 4}) or serpentine [Mg{sub 3}Si{sub 2}O{sub 5}(OH){sub 4}]. Carbon dioxide is dissolved into this slurry, by diffusion through the surface and gas dispersion within the aqueous phase. The process includes dissolution of the mineral and precipitation of the magnesium carbonate mineral magnesite (MgCO{sub 3}) in a single unit operation. Activation of the silicate minerals has been achieved by thermal and mechanical means, resulting in up to 80% stoichiometric conversion of the silicate to the carbonate within 30 minutes. Heat treatment of the serpentine, or attrition grinding of the olivine and/or serpentine, appear to activate the minerals by the generation of a non-crystalline phase. Successful conversion to the carbonate has been demonstrated at ambient temperature and relatively low (10 atm) partial pressure of CO{sub 2} (P{sub CO2}). However, optimum results have been achieved using the bicarbonate-bearing solution, and high P{sub CO2}. Specific conditions include: 185 C; P{sub CO2}=150 atm; 30% solids. Studies suggest that …

The new heavy ion synchrotron facility proposed by GSI will have two superconducting magnet rings in the same tunnel, with rigidities of 200T-m and 100T.m. Fast ramp times are needed, which can cause significant problems for the magnets, particularly in the areas of s c loss and field distortion. This paper discusses the 200T.m ring, which will use Cos0 magnets based on the RHIC dipole design. We discuss the reasons for choosing Rutherford cable with a resistive core and report loss measurements carried out on cable samples. These measurements are compared with theoretical calculations using measured values of inter-strand resistance. Reasonably good agreement is found, but there are indications of non-uniformity in the adjacent resistance R,. Using these measured parameters, losses and temperature rise are calculated for a RHIC dipole in the operating cycle of the accelerator. A novel insulation scheme designed to promote efficient cooling is described.

The nuclear/radioactive threat to homeland security posed by terrorists can be broken into four categories. Of highest concern is the use of an improvised nuclear device (IND). An IND, as its name implies, is a nuclear explosive device. It produces nuclear yield, and this nuclear yield has catastrophic effects. An IND is the ultimate terrorist weapon, and terrorist groups are actively attempting to acquire nuclear weapons. Detonation of an IND could dwarf the devastation of the September 11 attack on the World Trade Center. Dealing with the aftermath of an IND would be horrific. Rescue efforts and cleanup would be hazardous and difficult. Workers would have to wear full protection suits and self-contained breathing apparatus. Because of the residual radioactivity, in certain locations they could only work short times before acquiring their ''lifetime'' dose. As with the Chernobyl event, some rescue workers might well expose themselves to lethal doses of radiation, adding to the casualty toll. Enormous volumes of contaminated debris would have to be removed and disposed. If a terrorist group decides not to pursue an actual nuclear device, it might well turn to Radiological Dispersal Devices (RDDs) or ''dirty bombs'' as they are often called. RDDs spread radioactivity …

We have developed a pulser that is able to generate a simulated signal from a high-purity germanium (HPGe) detector for various plutonium isotopes. In this paper we describe the development of an ''isotopics'' pulser for the simulation of signals that are produced by an HPGe detector. The present pulser generates the waveforms that are produced by an HPGe detector both before and after the preamplifier. These signals have been input into a normal MCA and the result closely simulates a genuine pulse-height distribution.

This is the report of the Working Group on Early Universe Cosmology and tests of Fundamental Physics, group P4.8 of the of the Snowmass 2001 conference. Here we summarize the impressive array of advances that have taken place in this field, and identify opportunities for even greater progress in the future. Topics include Dark Energy, Cosmic Acceleration, Inflation, Phase Transitions, Baryogenesis, and String/M-theory Cosmology. The introductory section gives an executive summary with six key open questions on which we can expect to make significant progress.

Batch kinetic and column experiments have been carried out at 25, 35, and 45 Degrees C to examine the effect of temperature on SuperLig(R) 644 cesium (Cs) removal from simulated Hanford tank waste supernate. The simulated solution mimicked the composition of the low-activity waste supernate from tank 241-AN-105 in the U.S. DOE Hanford site. Small quantities of toxic metals, such as Cd, Cr, Fe, and Pb were spiked into the simulant to evaluate the metal's competitiveness with Cs for sorption on SuperLig(R) 644 resin. The results indicated that the temperature affects the removal of Cs and metal ions, although the effect was not the same for all metal ions. The extent of Cs removal decreased with an increase in temperature. The Cs capacity at breakthrough point was 0.015, 0.013, and 0.011-mmole/g dry resin at 25, 35 and 45 Degrees C, respectively. The column was effectively eluted to less than 1 Percent (0.1 C/Co) of the feed concentration with approximately 10 BVs of 0.5 M nitric acid. The resin showed limited affinity for toxic metal ions (Cr, Cd, Fe, and Pb) as compared to Cs. Based on the batch kinetic data, the Cs uptake of the resin was not hampered by …

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The rapid, Alfvenic, time scale of erupting solar-prominences has been an enigma ever since they where first identified. Investigators have proposed a variety of different mechanisms in an effort to account for the abrupt reconfiguration observed. No one mechanism clearly stands out as the single cause of these explosive events. Recent analysis has demonstrated that field lines in the solar atmosphere are metastable to ballooning type instabilities. It has been found previously that in ideal MHD plasmas marginally unstable ballooning modes inevitably become ''explosive'' evolving towards a finite time singularity via a nonlinear 3D instability called ''Nonlinear Magnetohydrodynamic Detonation.'' Thus, this mechanism is a good candidate to explain explosive events observed in the solar atmosphere of our star or in others.

In this paper we report on the first run II results from the CDF experiment. A brief description of the Tevatron collider and CDF detector upgrades and performance achieved in the first part of run II is followed by the CDF expectations in the fields of beauty, top, electroweak and Higgs physics.

In the past 50 years, fusion R&D programs have made enormous technical progress. Projected billion-dollar scale research facilities are designed to approach net energy production. In this century, scientific and engineering progress must continue until the economics of fusion power plants improves sufficiently to win large scale private funding in competition with fission and non-nuclear energy systems. This economic advantage must be sustained: trillion dollar investments will be required to build enough fusion power plants to generate ten percent of the world's energy. For Inertial Fusion Energy, multi-billion dollar driver costs must be reduced by up to an order of magnitude, to a small fraction of the total cost of the power plant. Major cost reductions could be achieved via substantial improvements in target performance-both higher gain and reduced ignition energy. Large target performance improvements may be feasible through a combination of design innovations, e.g., ''fast ignition,'' propagation down density gradients, and compression of fusion fuel with a combination of driver and chemical energy. The assumptions that limit projected performance of fusion targets should be carefully examined. The National Ignition Facility will enable development and testing of revolutionary targets designed to make possible economically competitive fusion power plants.