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''Hidden'' geothermal systems are systems devoid of obvious surface hydrothermal manifestations. Emissions of moderate-to-low solubility gases may be one of the primary near-surface signals from these systems. We investigate the potential for CO2 detection and monitoring below and above ground in the near-surface environment as an approach to exploration targeting hidden geothermal systems. We focus on CO2 because it is the dominant noncondensible gas species in most geothermal systems and has moderate solubility in water. We carried out numerical simulations of a CO2 migration scenario to calculate the magnitude of expected fluxes and concentrations. Our results show that CO2 concentrations can reach high levels in the shallow subsurface even for relatively low geothermal source CO2 fluxes. However, once CO2 seeps out of the ground into the atmospheric surface layer, winds are effective at dispersing CO2 seepage. In natural ecological systems in the absence of geothermal gas emissions, near-surface CO2 fluxes and concentrations are predominantly controlled by CO2 uptake by photosynthesis, production by root respiration, microbial decomposition of soil/subsoil organic matter, groundwater degassing, and exchange with the atmosphere. Available technologies for monitoring CO2 in the near-surface environment include the infrared gas analyzer, the accumulation chamber method, the eddy covariance method, hyperspectral …

Interaction of an electron beam with a femtosecond laserpulseco-propagating through a wiggler modulates the electronenergieswithin a short slice of the electron bunch comparable with the durationof the laser pulse (Figure 1). Propagating around an electron storagering, this bunch develops a longitudinal density perturbation due to thedispersion of electron trajectories. Figure 1 shows how this createsfemtosecond electron bunch wings which are used for femtosecond x-raylight. In addition, this density perturbation emits temporally andspatially coherent tera-hertz pulses whichare inherently synchronized tothe modulating laser. This gives us a new way to study coherentsynchrotron radaition, and creates an opportunity for tuning the THzemmission specifically for the needs of a given experiment.

Spent nuclear fuels from foreign and domestic research and test reactors are being returned to the Savannah River Site for storage with other nuclear materials in the L-Basin. Recent efforts have consolidated the fuel storage systems and L-Basin has become the SRS site for wet storage of spent nuclear fuels. Corrosion surveillance of coupons in this basin is being performed to provide assurance of safe storage of spent fuel. This paper describes the highlights of recent studies on these aluminum coupons after immersion for more than 7 years in L-Basin. Selected coupons were metallurgically characterized to establish the existence of general corrosion and pitting. Minor pitting corrosion was observed on the intentionally galvanically coupled samples and creviced coupons, thus demonstrating that localized concentration cells were formed during the exposure period. In these cases, the susceptibility to pitting was not attributed to aggressive basin water chemistry but to localized conditions--crevices and galvanic coupling--that allowed the development of oxygen and/or metal ion concentration cells that produced locally aggressive waters. General corrosion was also observed on some of the coupons. None of the coupons were pre-oxidized to form a protective oxide as compared to the spent fuel which was oxidized during reactor operations. …

A new parsimony analysis of 27 complete mitochondrial genomic sequences is conducted to investigate the phylogenetic relationships of plethodontid salamanders. This analysis focuses on the amount of character conflict between phylogenetic trees recovered from newly conducted parsimony searches and the Bayesian and maximum likelihood topology reported by Mueller et al. (2004, PNAS, 101, 13820-13825). Strong support for Hemidactylium as the sister taxon to all other plethodontids is recovered from parsimony analyses. Plotting area relationships on the most parsimonious phylogenetic tree suggests that eastern North America is the origin of the family Plethodontidae supporting the ''Out of Appalachia'' hypothesis. A new taxonomy that recognizes clades recovered from phylogenetic analyses is proposed.

This presentation was given at the DOE Office of Science-Environmental Management Science Program (EMSP) High-Level Waste Workshop held on January 19-20, 2005 at the Savannah River Site.

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The primary mission of the Tritium Extraction Facility (TEF) is to extract tritium from tritium producing burnable absorber rods (TPBARs) that have been irradiated in a commercial light water reactor and to deliver tritium-containing gas to the Savannah River Site Facility 233-H. The tritium extraction segment provides the capability to deliver three (3) kilograms per year to the nation's nuclear weapons stockpile. The TEF includes processes, equipment and facilities capable of production-scale extraction of tritium while minimizing personnel radiation exposure, environmental releases, and waste generation.

Lepton flavor violation (LFV) experiments have probed sensitivities corresponding to mass scales of well over 100 TeV, making life difficult for models predicting accessible LFV in kaon decay and discouraging new dedicated experiments of this type.

A general quantum-mechanical method for computing kinetic isotope effects is presented. The method is based on the quantum instanton approximation for the rate constant and on the path integral Metropolis Monte-Carlo evaluation of the Boltzmann operator matrix elements. It computes the kinetic isotope effect directly, using a thermodynamic integration with respect to the mass of the isotope, thus avoiding the more computationally expensive process of computing the individual rate constants. The method is more accurate than variational transition-state theories or the semiclassical instanton method since it does not assume a single reaction path and does not use a semiclassical approximation of the Boltzmann operator. While the general Monte-Carlo implementation makes the method accessible to systems with a large number of atoms, we present numerical results for the Eckart barrier and for the collinear and full three-dimensional isotope variants of the hydrogen exchange reaction H+H{sub 2} {yields} H{sub 2}+H. In all seven test cases, for temperatures between 250 K and 600 K, the error of the quantum instanton approximation for the kinetic isotope effects is less than {approx}10%.

In support of Stockpile Stewardship activities, accelerated aging tests on a plutonium alloy enriched with 7.3 atomic percentage of {sup 238}Pu is underway using dilatometry at 35, 50, and 65 C and immersion density measurements of material stored at 50 C. Changes in density are expected from radiation damage in the lattice and helium in-growth. After twenty-five equivalent years of aging, the dilatometry data shows that the alloys at 35 C have expanded in volume by 0.11% to 0.12% and have started to exhibit a near linear expansion behavior primarily caused by the helium accumulation. The average He-to-vacancy ratio from tested specimens was determined to be around 2.3. The model for the lattice damage and helium in-growth accurately represents the volume swelling at 35 C. The density converted from the dilatometry corresponds well to the decreasing density trend of reference plutonium alloys as a function of time.

The DECOVALEX project is an international cooperative project initiated by SKI, the Swedish Nuclear Power Inspectorate, with participation of about 10 international organizations. The general goal of this project is to encourage multidisciplinary interactive and cooperative research on modeling coupled thermo-hydro-mechanical-chemical (THMC) processes in geologic formations in support of the performance assessment for underground storage of radioactive waste. One of the research tasks, initiated in 2004 by the U.S. Department of Energy (DOE), addresses the long-term impact of geomechanical and geochemical processes on the flow conditions near waste emplacement tunnels. Within this task, four international research teams conduct predictive analysis of the coupled processes in two generic repositories, using multiple approaches and different computer codes. Below, we give an overview of the research task and report its current status.

We present modeling results for the propagation of strong shock waves in metals. In particular, we use an arbitrary Lagrange Eulerian (ALE3D) code to model the propagation of strong pressure waves (P {approx} 300 to 400 kbars) generated with high explosives in contact with aluminum cylinders. The aluminum cylinders are assumed to be both flat-topped and have large-amplitude curved surfaces. We use 3D Lagrange mechanics. For the aluminum we use a rate-independent Steinberg-Guinan model, where the yield strength and shear modulus depend on pressure, density and temperature. The calculation of the melt temperature is based on the Lindermann law. At melt the yield strength and shear modulus is set to zero. The pressure is represented as a seven-term polynomial as a function of density. For the HMX-based high explosive, we use a JWL, with a program burn model that give the correct detonation velocity and C-J pressure (P {approx} 390 kbars). For the case of the large-amplitude curved surface, we discuss the evolving shock structure in terms of the early shock propagation experiments by Sakharov.

We report on searches for B{sup -} {yields} D{sub s}{sup -} {phi} and B{sup -} {yields} D*{sub s}{sup -} {phi}. In the context of the Standard Model, these decays are expected to be highly suppressed since they proceed through annihilation of the b and {bar u} quarks in the B{sup -} meson. Our results are based on 234 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at SLAC. We find no evidence for these decays, and we set Bayesian 90% confidence level upper limits on the branching fractions {Beta}(B{sup -} {yields} D{sub s}{sup -}{phi}) < 1.9 x 10{sup -6} and {Beta}(B{sup -} {yields} D*{sub s}{sup -} {phi}) < 1.2 x 10{sup -5}. These results are consistent with Standard Model expectations.

We report a full-vector, three-dimensional, numerical solution of Maxwell's equations for optical propagation within, and scattering by, a random medium of macroscopic dimensions. The total scattering cross-section is determined using the pseudospectral time-domain technique. Specific results reported in this Paper indicate that multiply scattered light also contains information that can be extracted by the proposed cross-correlation analysis. On a broader perspective, our results demonstrate the feasibility of accurately determining the optical characteristics of arbitrary, macroscopic random media, including geometries with continuous variations of refractive index. Specifically, our results point toward the new possibilities of tissue optics--by numerically solving Maxwell's equations, the optical properties of tissue structures can be determined unambiguously.

Coherent X-ray diffraction microscopy is a method of imaging non-periodic isolated objects at resolutions only limited, in principle, by the largest scattering angles recorded. We demonstrate X-ray diffraction imaging with high resolution in all three dimensions, as determined by a quantitative analysis of the reconstructed volume images. These images are retrieved from the 3D diffraction data using no a priori knowledge about the shape or composition of the object, which has never before been demonstrated on a non-periodic object. We also construct 2D images of thick objects with infinite depth of focus (without loss of transverse spatial resolution). These methods can be used to image biological and materials science samples at high resolution using X-ray undulator radiation, and establishes the techniques to be used in atomic-resolution ultrafast imaging at X-ray free-electron laser sources.

Detection of breast cancer in fresh tissue obtained from surgery is investigated using Near-infrared autofluorescence imaging under laser excitation at 532-nm and 632.8-nm. The differences in intensity between the three main components of breast tissue (cancer, fibrous and adipose) are estimated and compared to those obtained from cross-polarized light scattering images recorded under polarized illumination at 700-nm. The optical spectroscopic images for each tissue sample were subsequently compared with the histopathology slides. The experimental results indicate that the intensity of the near-infrared emission is considerably different in breast cancer compared to that of the adjacent non-neoplastic tissues (adipose and fibrous tissue). The experimental results suggest that 632.8-nm excitation offers key advantages compared to 532-nm excitation.

In this note we give multiple examples of the recently proposed New Attractors describing supersymmetric flux vacua and non-supersymmetric extremal black holes in IIB string theory. Examples of non-supersymmetric extremal black hole attractors arise on a hypersurface in WP{sub 1,1,1,1,2}{sup 4}. For flux vacua on the orientifold of the same hypersurface existence of multiple basins of attraction is established. It is explained that certain fluxes may give rise to multiple supersymmetric flux vacua in a finite region on moduli space, say at the Landau-Ginzburg point and close to conifold point. This suggests the existence of multiple basins for flux vacua and domain walls in the landscape for a fixed flux and at interior points in moduli space.

We discuss simulated photonic crystal structure designs for laser-driven particle acceleration, focusing on three-dimensional planar structures based on the so-called ''woodpile'' lattice. We demonstrate guiding of a speed-of-light accelerating mode by a defect in the photonic crystal lattice and discuss the properties of this mode. We also discuss particle beam dynamics in the structure, presenting a novel method for focusing the beam. In addition we describe some potential coupling methods for the structure.

The results of searches for the strange pentaquark states, {Theta}{sub 5}(1540){sup +}, {Xi}{sub 5}(1860){sup --} and {Xi}{sub 5}(1860){sup 0} in data recorded by the BABAR experiment are presented. We search for these three states inclusively in 123.4 fb{sup -1} of e{sup +}e{sup -} annihilation data produced at the PEP-II asymmetric storage rings; we find no evidence for their production in any physics process, and set limits on their production rates that are well below the measured rates for conventional baryons. We also search for {Theta}{sub 5}(1540){sup +} produced in interactions of electrons or hadrons in the material of the inner part of the detector. No evidence for this state is found in a sample with much higher statistics than similar electroproduction experiments that claim a signal.

Shock initiation experiments on the explosive PBX9501 (95% HMX, 2.5% estane, and 2.5% nitroplasticizer by weight) were performed at 150 C to obtain in-situ pressure gauge data and Ignition and Growth modeling parameters. A 101 mm diameter propellant driven gas gun was utilized to initiate the PBX9501 explosive with manganin piezoresistive pressure gauge packages placed between sample slices. The run-distance-to-detonation points on the Pop-plot for these experiments showed agreement with previously published data and Ignition and Growth modeling parameters were obtained with a good fit to the experimental data. This parameter set will allow accurate code predictions to be calculated for safety scenarios involving PBX9501 explosives at temperatures close to 150 C.

Adaptive perturbation is a new method for perturbatively computing the eigenvalues and eigenstates of quantum mechanical Hamiltonians that are widely believed not to be solvable by such methods. The novel feature of adaptive perturbation theory is that it decomposes a given Hamiltonian, H, into an unperturbed part and a perturbation in a way which extracts the leading non-perturbative behavior of the problem exactly. In this talk I will introduce the method in the context of the pure anharmonic oscillator and then apply it to the case of tunneling between symmetric minima. After that, I will show how this method can be applied to field theory. In that discussion I will show how one can non-perturbatively extract the structure of mass, wavefunction and coupling constant renormalization.

The Optimized Sparse Kernel Interface (OSKI) is a collection of low-level primitives that provide automatically tuned computational kernels on sparse matrices, for use by solver libraries and applications. These kernels include sparse matrix-vector multiply and sparse triangular solve, among others. The primary aim of this interface is to hide the complex decision-making process needed to tune the performance of a kernel implementation for a particular user's sparse matrix and machine, while also exposing the steps and potentially non-trivial costs of tuning at run-time. This paper provides an overview of OSKI, which is based on our research on automatically tuned sparse kernels for modern cache-based superscalar machines.

We present results for measurements of B{sup 0} meson decays to charmless final states {eta}K{sup 0}, {eta}{omega}, a{sub 1}{sup +}(1260){pi}{sup -} with a{sub 1}{sup +}(1260) {yields} {pi}{sup +}{pi}{sup +}{pi}{sup -}, {rho}{sup 0}K{sub S}{sup 0}, K{sub S}{sup 0}K{sub S}{sup 0}K{sub S}{sup 0}, and of B{sup +} to {eta}{rho}{sup +} and {eta}{prime}{pi}{sup +}. Analyses are based on data taken with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC.