The Republic of Kazakhstan is continuing to develop its extensive petroleum reserves in the Tengiz region of the northeastern part of the Caspian Sea. Large quantities of by-product sulfur are being produced as a result of the removal of hydrogen sulfide from the oil and gas produced in the region. Lack of local markets and economic considerations limit the traditional outlets for by-product sulfur and the buildup of excess sulfur is a becoming a potential economic and environmental liability. Thus, new applications for re-use of by-product sulfur that will benefit regional economies including construction, paving and waste treatment are being developed. One promising application involves the cleanup and treatment of mercury at a Kazakhstan chemical plant. During 19 years of operation at the Pavlodar Khimprom chlor-alkali production facility, over 900 tons of mercury was lost to the soil surrounding and beneath the buildings. The Institute of Metallurgy and Ore Benefication (Almaty) is leading a team to develop and demonstrate a vacuum-assisted thermal process to extract the mercury from the soil and concentrate it as pure, elemental mercury, which will then be treated using the Sulfur Polymer Stabilization/Solidification (SPSS) process. The use of locally produced sulfur will recycle a low-value industrial …

We consider the collinear limit of QCD amplitudes at one-loop order, and their factorization properties directly in color space. These results apply to the multiple collinear limit of an arbitrary number of QCD partons, and are a basic ingredient in many higher-order computations. In particular, we discuss the triple collinear limit and its relation to flavor asymmetries in the QCD evolution of parton densities at three loops. As a phenomenological consequence of this new effect, and of the fact that the nucleon has non-vanishing quark valence densities, we study the perturbative generation of a strange-antistrange asymmetry s(x)-{bar s}(x) in the nucleon's sea.

Soils and sediments contaminated with toxic organic and inorganic compounds harmful to the environment and to human health are common in the urban environment. We report here on aspects of a program being carried out in the New York/New Jersey Port region to develop methods for processing dredged material from the Port to make products that are safe for introduction to commercial markets. We discuss some of the results of the program in Computational Environmental Science, Laboratory Environmental Science, and Applied Environmental Science and indicate some possible directions for future work. Overall, the program elements integrate the scientific and engineering aspects with regulatory, commercial, urban planning, local governments, and community group interests. Well-developed connections between these components are critical to the ultimate success of efforts to cope with the problems caused by contaminated urban soils and sediments.

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This study presents a technique that can significantly improve the performance of a distributed application by allowing the application to locally adapt to architectural characteristics of distinct resources in a distributed system. Application performance is sensitive to application parameter--system architecture pairings. In a distributed or Grid enabled applciation, a single parameter configuration for the whole application will not always be optimal for every participating resource. In particular, some configurations can significantly degrade performance. Furthermore, the behavior of a system may change during the course of the run. The technique described here provides an automated mechanism for run-time adaptation of application parameters to the local system architecture. Using a simulation of a Monte Carlo physics code, the authors demonstrate that this technique can achieve speedups of 18%-37% on individual resources in a distributed environment.

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, …

This health and safety guide was written to satisfy two objectives: to summarize the toxicity of metals and alloys used in superconductivity for the benefit of those who work with these materials, and to summarize and describes the basic principles of a highly technical field from a health and safety point-of-view for the benefit of health professionals. The guide begins with a profile of the superconductivity industry, including a list of current and potential applications, a literature review of the market potential, and summary of the current industry status. The body of the paper provides a toxicity and hazard summary for 50 metals, alloys and metal oxides used in superconductivity. The toxicity and hazard summary for all 50 compounds includes: occupational exposure limits, explosiveness and flammability potential, LD{sub 50}'s, chemical and physical properties, incompatibilities and reactivities, recommended personal protective equipment, symptoms of acute and chronic exposure, target organs and toxic effects, and steps for emergency first aid. Finally, a discussion of general occupational hygiene principles is provided, with emphasis on how these principles apply to the unique field of superconductivity. 41 refs.

We present position sensitivity measurements obtained with one of the 32-fold segmented HPGe detectors from Michigan State University. These measurements were performed with a collimated beam of {sup 137}Cs gamma rays scattered by 90 degrees. This deposits 374 keV at a given location inside the crystal. A position resolution can be determined over many events by examining the digitally recorded pulse shapes on the 32 electrical contacts. If position resolution is adequate, gamma ray Compton camera imaging may be possible.

The 27 GPa pressure-induced epsilon-phi phase transition in HMX is explored using the Isentropic Compression Experiment (ICE) technique at the Sandia National Laboratories Z-machine facility. Our data indicate that this phase transition is sluggish and if it does occur to any extent under the time scales (200-500 ns) and strain rates (5 x 10{sup 5}) typical of ICE loading conditions, the amount of conversion is small.

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A distributed memory message-passing parallel implementation of a finite-volume discretization of the primitive equations in the Community Atmosphere Model is presented. Due to the data dependencies resulting from the polar singularity of the latitude-longitude coordinate system, it is necessary to employ two separate domain decompositions within the dynamical core. Data must be periodically redistributed between these two decompositions. In addition, the domains contain halo regions that cover the nearest neighbor data dependencies. A combination of several techniques, such as one-sided communication and multithreading, are presented to optimize data movements. The resulting algorithm is shown to scale to very large machine configurations, even for relatively coarse resolutions.

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The finite element method has been routinely used to calculate the image stresses of dislocation segments. When these segments intersect with surfaces, the image stresses at the surfaces diverges singularly. At the presence of these singularities, both convergence and accuracy of using the finite element method need to be examined critically. This article addresses these issues with the aim toward the application of dislocation dynamics simulations in thin films.

The in-plane optical properties of two crystals of the bilayer cuprate La{sub 2-x}(Ca,Sr){sub x}Ca,Sr){sub x}CaCu{sub 2}O{sub 6+{delta}}, one with excess Ca and x = 0.10 and the other with Sr and x = 0.15, were investigated over the frequency range of 45-25000 cm{sup -1}. A metallic response both in frequency and temperature was observed for Sr = 0.15 superconducting sample at low frequencies. Meanwhile, the sample also exhibits a prominent charge-transfer excitation at around 15000 cm{sup -1}. This observation, together with neutron experiments performed on the same sample showing diffuse, elastic antiferromagnetic scattering, indicate that the quasi-mobile carriers coexist at low temperature with static antiferromagnetic clusters. This coexistence indicates intrinsic spatial inhomogeneity.

A current focus of our weapon headspace sampling work is the interpretation of the volatile chemical signatures that we are collecting. To help validate our interpretation we have been developing a laboratory-based material aging capability to simulate material decomposition chemistries identified. Key to establishing this capability has been the development of an automated approach to process, analyze, and quantify arrays of material combinations as a function of time and temperature. Our initial approach involves monitoring the formation and migration of volatile compounds produced when a material decomposes. This approach is advantageous in that it is nondestructive and provides a direct comparison with our weapon headspace surveillance initiative. Nevertheless, this approach requires us to identify volatile material residue and decomposition byproducts that are not typically monitored and reported in material aging studies. Similar to our weapon monitoring method, our principle laboratory-based method involves static headspace collection by solid phase microextraction (SPME) followed by gas chromatography/mass spectrometry (GC/MS). SPME is a sorbent collection technique that is ideally suited for preconcentration and delivery of trace gas-phase compounds for analysis by GC. When combined with MS, detection limits are routinely in the low- and sub-ppb ranges, even for semivolatile and polar compounds. To automate …

The heavy-ion fusion (HIF) community recently developed a power-plant design that meets the various requirements of accelerators, final focus, chamber transport, and targets. The point design is intended to minimize physics risk and is certainly not optimal for the cost of electricity. Recent chamber-transport simulations, however, indicate that changes in the beam ion species, the convergence angle, and the emittance might allow more-economical designs.

Under anaerobic conditions and at circumneutral pH, cells of the widely-distributed, obligate chemolithoautotrophic bacterium Thiobacillus denitrificans oxidatively dissolved synthetic and biogenic U(IV) oxides (uraninite) in nitrate-dependent fashion: U(IV) oxidation required the presence of nitrate and was strongly correlated to nitrate consumption. This is the first report of anaerobic U(IV) oxidation by an autotrophic bacterium.

We suggest a new class of high-flux renewable optics, in particular, for the use at the X-ray free electron laser, LCLS, which is under discussion now. The size of optical elements we have in mind is from a fraction of a square centimeter to a few square centimeters. We suggest that working fluid be pressed through a porous substrate (made, e.g., of fused capillaries) to form a film, a few tens to a hundred microns thick. After the passage of an intense laser pulse, the liquid film is sucked back through the substrate by a reversed motion of the piston, and formed anew before the next pulse. The working surface of the film is made flat by capillary forces. We discuss the role of viscous, gravitational, and capillary forces in the dynamics of the film and show that the properly made film can be arbitrarily oriented with respect to the gravitational force. This makes the proposed optics very flexible. We discuss effects of vibrations of the supporting structures on the quality of optical elements. Limitations on the radiation intensity are formulated. We show how the shape of the film surface can be controlled by electrostatic and magnetic forces, allowing one …

Understanding and predicting the behavior of high-Z non-LTE plasmas is important for developing indirect-drive inertial confinement fusion. Extending earlier work from the Nova laser, we present results from experiments using the Omega laser to study the ionization balance of gold as a function of electron and radiation temperature. In these experiments, gold samples embedded in Be disks expand under direct laser heating to n{sub e} {approx} 10{sup 21} cm{sup -3}, with T{sub e} varying from 0.8 to 2.5 keV. An additional finite radiation field with effective temperature T{sub r} up to 150 eV is provided by placing the gold-Be disks inside truncated 1.2 mm diameter tungsten-coated cylindrical hohlraums with full laser entrance holes. Densities are measured by imaging of plasma expansion. Electron temperatures are diagnosed with either 2 {omega} or 4 {omega} Thomson scattering, and also K-shell spectroscopy of KCl tracers co-mixed with the gold. Hohlraum flux and effective radiation temperature are measured using an absolutely-calibrated multichannel filtered diode array. Spectroscopic measurements of the M-shell gold emission in the 2.9-4 keV spectral range provide ionization balance and charge state distribution information. The spectra show strong variation with T{sub e}, strong variation with the applied T{sub r} at T{sub e} below …

Current ideas [1,2] for designing a high luminosity muon collider require significant cooling of the phase space of the muon beams. The only known method that can cool the beams in a time comparable to the muon lifetime is ionization cooling [3,4]. This method requires directing the particles in the beam at a large angle through a low Z absorber material in a strong focusing magnetic channel and then restoring the longitudinal momentum with an rf cavity. We have developed a new 3-D tracking code ICOOL for examining possible configurations for muon cooling. A cooling system is described in terms of a series of longitudinal regions with associated material and field properties. The tracking takes place in a coordinate system that follows a reference orbit through the system. The code takes into account decays and interactions of {approx}50-500 MeV/c muons in matter. Material geometry regions include cylinders and wedges. A number of analytic models are provided for describing the field configurations. Simple diagnostics are built into the code, including calculation of emittances and correlations, longitudinal traces, histograms and scatter plots. A number of auxiliary files can be generated for post-processing analysis by the user.

The increasing presence of computers and other forms of information and communications technology (ICT) in schools has raised concerns in the United States (US) and elsewhere. Children are using computers more than any other age group in the US. It is not known whether early intensive use of ICT predisposes children to future injury. Ergonomics is not included in state curriculum standards or requirements but can be supported by some of the existing standards. Some who believe that children are better off being educated early about ergonomics are taking action to bring ergonomics into elementary and secondary schools. This paper describes the process used to introduce ergonomics into two elementary schools in two different states by initiators with two different roles.

This work studies multiscale phenomena in silicon micro-resonators which comprise the mechanical components of next-generation Micro-Electro-Mechanical Systems (MEMS). Unlike their larger relatives, the behavior of these sub-micron MEMS is not described well by conventional continuum models and finite elements, but it is determined appreciably by the interplay between physics at the Angstrom, nanometer and micron scales. As device sizes are reduced below the micron scale, atomistic processes cause systematic deviations from the behavior predicted by conventional continuum elastic theory. [1] These processes cause anomalous surface effects in the resonator frequency and quality factor--even for single crystal devices with clean surfaces due to thermal fluctuations. They also lead to unconventional failure mechanisms. The simulation of these atomistic effects is a challenging problem due to the large number of atoms involved and due to the fact that they are finite temperature phenomena. Our simulations include up to two million atoms in the device itself, and hundreds of millions more are in the proximal regions of the substrate. A direct, atomistic simulation of the motion of this many atoms is prohibitive, and it would be inefficient. The micronscale processes in the substrate are well-described by finite elements, and an atomistic simulation is not …

Alumina aerogels were prepared through the addition of propylene oxide to aqueous or ethanolic solutions of hydrated aluminum salts, AlCl{sub 3} {center_dot} 6H{sub 2}O or Al(NO{sub 3}){sub 3} {center_dot} 9H{sub 2}O, followed by drying with supercritical CO{sub 2}. This technique affords low-density (60-130 kg/m{sup 3}), high surface area (600-700 m{sup 2}/g) alumina aerogel monoliths without the use of alkoxide precursors. The dried alumina aerogels were characterized using elemental analysis, high-resolution transmission electron microscopy, powder X-ray diffraction, solid state NMR, acoustic measurements and nitrogen adsorption/desorption analysis. Powder X-ray diffraction and TEM analysis indicated that the aerogel prepared from hydrated AlCl{sub 3} in water or ethanol possessed microstructures containing highly reticulated networks of pseudoboehmite fibers, 2-5 nm in diameter and of varying lengths, while the aerogels prepared from hydrated Al(NO{sub 3}){sub 3} in ethanol were amorphous with microstructures comprised of interconnected spherical particles with diameters in the 5-15 nm range. The difference in microstructure resulted in each type of aerogel displaying distinct physical and mechanical properties. In particular, the alumina aerogels with the weblike microstructure were far more mechanically robust than those with the colloidal network, based on acoustic measurements. Both types of alumina aerogels can be transformed to {gamma}-Al{sub 2}O{sub 3} …

A new small-scale Detonation Profile Test (DPT) is being developed to investigate aging effects on the detonation behavior of insensitive high explosives. The experiment involves initiating a small LX-17 cylindrical charge (12.7-19.1 mm diameter x 25.4-33 mm long) and measuring the velocity and curvature of the emerging detonation wave using a streak camera. Results for 12.7 mm diameter unconfined LX-17 charges show detonation velocity in the range between 6.79 and 7.06 km/s for parts up to 33 mm long. Since LX-17 can not sustain detonation at less than 7.3 km/s, these waves were definitely failing. Experiments with confined 12.7 mm diameter and unconfined 19.1 mm diameter samples showed wave velocities in the range of 7.4-7.6 km/s, values approaching steady state conditions at infinite diameter. Experiments with unconfined 19.1 mm diameter specimens are expected to provide reproducible and useful range of detonation parameters suitable for studying aging effects.