During the past 50 years Transmission Electron Microscopy (TEM) has evolved from an imaging tool to a quantitative method that approaches the ultimate goal of understanding the atomic structure of materials atom by atom in three dimensions both experimentally and theoretically. Today's TEM abilities are tested in the special case of a Ga terminated 30 degree partial dislocation in GaAs:Be where it is shown that a combination of high-resolution phase contrast imaging, Scanning TEM, and local Electron Energy Loss Spectroscopy allows for a complete analysis of dislocation cores and associated stacking faults. We find that it is already possible to locate atom column positions with picometer precision in directly interpretable images of the projected crystal structure and that chemically different elements can already be identified together with their local electronic structure. In terms of theory, the experimental results can be quantitatively compared with ab initio electronic structure total energy calculations. By combining elasticity theory methods with atomic theory an equivalent crystal volume can be addressed. Therefore, it is already feasible to merge experiments and theory on a picometer length scale. While current experiments require the utilization of different, specialized instruments it is foreseeable that the rapid improvement of electron optical …

The work presented herein is a study of the effect of temperature on the absolute permeability to distilled water of unconsolidated sandstones at one confining pressure. The absolute permeability to distilled water of Ottawa silica sand was not dependent on the temperature level.

The main purpose of this work is to show that it is possible to calculate the sandface flowrate given wellhead conditions and the downhole pressure transients. It is not necessary t o know anything about the reservoir itself. First, it is of interest to look at the nonuniform pressure changes in the well, and to illustrate nonisothermal effects on pressure transient data.

The large number of nonproductive wells lying along the northern and western margins of the Larderello field have indicated some boundaries of the productive area but have also prevented us, so far, from fully understanding the pheiomena controlling the behavior of the geothermal system in these areas. In 1980 ENEL re-opened some wells that had been shut-in immediately after drilling, thus offering us the possibility to complete the geochemical picture by means of numerous samplings of steam, gas and water in both productive and nonproductive wells. Some recent physical parameters measured in nonproductive and abandoned wells also helped in further defining the hydrogeological and thermal situation.

The Raft River 5 MW power plant will be on-line some time this spring. During testing of the supply and injection system prior to plant start-up and during testing of the plant itself, data can be collected and used to calibrate computer models, refine predicted drawdowns and interference effects, monitor changing temperatures, and recalculate reservoir parameters. Analytic methods have been used during reservoir testing at Raft River to calculate reservoir coefficients. However, anisotropy of the reservoir due t o fractures has not been taken into account i n these calculations and estimates of these coefficients need to be refined. From refined estimates of reservoir coefficients better predictions of interference effects and long-term drawdown in the wells can be made. In conjunction with the USGS, Faust and Mercer's 3-D finite difference model has been used to simulate the Raft River geothermal field. Intera used a 2-D simulator to predict temperatures, pressures over 30 years and movement of dissolved solids in the reservoir. Data collected during production of the field will be compared to these simulations and the models refined.

We describe simulation of the transient evolution of a "cold" hydrothermal system into a steady-state partially vapor-dominated system. In our study we have neglected the effects of salts and gases and have assumed that rock properties are time independent and homogeneous within each part of the system. Despite these simplifications we believe that our model demonstrates the essential features of a natural hydrothermal convection system (NHCS).

This paper discusses a procedure for estimating the value of a hot water geothermal property from a resource owner's point of view. Two methods make up the procedure: a "conservative" method of estimation and an "optimistic" one. Value of a property by both methods is estimated t o equal the present value of future income less the cost of resource extraction. The two methods share a common set of assumptions (e.g., that the price of hot water at the start of cash flow from a project will be the same). However, the methods differ in important ways. The optimistic method, for example, allows for future increase in price that in turn offsets discounting of future income. Together the methods define a range of values that might reasonably be assigned to a property.

The little Higgs model provides an alternative to traditional candidates for new physics at the TeV scale. The new heavy gauge bosons predicted by this model should be observable at the Large Hadron Collider (LHC). We discuss how the LHC experiments could test the little Higgs model by studying the production and decay of these particles.

Laser induced growth of optical damage can limit component lifetime and therefore operating costs of large-aperture fusion-class laser systems. While far-infrared (IR) lasers have been used previously to treat laser damage on fused silica optics and render it benign, little is known about the effectiveness of less-absorbing mid-IR lasers for this purpose. In this study, they quantitatively compare the effectiveness and efficiency of mid-IR (4.6 {micro}m) versus far-IR (10.6 {micro}m) lasers in mitigating damage growth on fused silica surfaces. The non-linear volumetric heating due to mid-IR laser absorption is analyzed by solving the heat equation numerically, taking into account the temperature-dependent absorption coefficient {alpha}(T) at {lambda} = 4.6 {micro}m, while far-IR laser heating is well-described by a linear analytic approximation to the laser-driven temperature rise. In both cases, the predicted results agree well with surface temperature measurements based on infrared radiometry, as well as sub-surface fictive temperature measurements based on confocal Raman microscopy. Damage mitigation efficiency is assessed using a figure of merit (FOM) relating the crack healing depth to laser power required, under minimally-ablative conditions. Based on their FOM, they show that for cracks up to at least 500 {micro}m in depth, mitigation with a 4.6 {micro}m mid-IR laser …

Magnetic order and coupling at the interfaces of highly spin polarized Fe{sub 3}O{sub 4} heterostructures have been determined by surface sensitive and element specific soft x-ray spectroscopy and spectromicroscopy techniques. At ambient temperature, the interface between paramagnetic CoCr{sub 2}O{sub 4} or MnCr{sub 2}O{sub 4} and ferrimagnetic Fe{sub 3}O{sub 4} isostructural bilayers exhibits long range magnetic order of Co, Mn and Cr cations which cannot be explained in terms of the formation of interfacial MnFe{sub 2}O{sub 4} or CoFe{sub 2}O{sub 4}. Instead, the ferrimagnetism is induced by the adjacent Fe{sub 3}O{sub 4} layer and is the result of the stabilization of a spinel phase not achievable in bulk form. Magnetism at the interface region is observable up to 500 K, far beyond the chromite bulk Curie temperature of 50-95 K.

The authors present direct measurements of the spatial distribution of ionizing radiation and low energy neutrons (E{sub n} < 200 keV) inside the tracking volume of the collider detector at Fermilab (CDF). Using data from multiple exposures, the radiation field can be separated into components from beam losses and collisions and can be checked for consistency between the measurements. They compare the radiation measurements with an increase in the leakage currents of the CDF silicon detectors and find reasonable agreement.

The authors examine the transient residual thermal signal resulting from an underground nuclear test (buried below the water table) and its potential to affect local groundwater flow and radionuclide migration in a saturated, fractured, volcanic aquifer system. Thermal profiles measured in a drillback hole between 154 days and 6.5 years after the test have been used to calibrate a non-isothermal model of fluid flow. In this process, they have estimated the magnitude and relative changes in permeability, porosity and fracture density between different portions of the disturbed and undisturbed geologic medium surrounding the test location. The relative impacts of buoyancy forces (arising from the thermal residual of the test and the background geothermal gradient) and horizontal pressure gradients on the post-test flow system are better understood. A transient particle/streamline model of contaminant transport is used to visualize streamlines and streaklines of the flow field and to examine the migration of non-reactive radionuclides. Sensitivity analyses are performed to understand the effects of local and sub-regional geologic features, and the effects of fractured zones on the movement of groundwater and thermal energy. Conclusions regarding the overall effect of the thermal regime on the residence times and fluxes of radionuclides out of the …

Candidate immobilization forms for the disposal of surplus weapons-useable are being tested and characterized. The goal of the testing program was to provide sufficient data that, by August 1997, an informed selection of a single immobilization form could be made so that the form development and production R and D could be more narrowly focused. Two forms have been under consideration for the past two years: glass and ceramic. In August, 1997, the Department of Energy (DOE) selected ceramic for plutonium disposition, halting further work on the glass material. In this paper, we will briefly describe these two waste forms, then describe our characterization techniques and testing methods. The analytical methods used to characterize altered and unaltered samples are the same. A full suite of microscopic techniques is used. Techniques used include optical, scanning electron, and transmission electron microscopies. For both candidate immobilization forms, the analyses are used to characterize the material for the presence of crystalline phases and amorphous material. Crystalline materials, either in the untested immobilization form or in the alteration products from testing, are characterized with respect to morphology, crystal structure, and composition. The goal of these analyses is to provide data on critical issues such as …

The construction of the initial part of the J-PARC linac has been started at KEK for beam tests before moving to the JAERI Tokai campus, where J-PARC facility is finally to be constructed. The RFQ and MEBT (Medium Energy Beam Transport) has already been installed at KEK, and the beam test has been performed successfully. In this paper, the experimental results of the beam test are compared with simulation results with a 3D PIC (Particle-In-Cell) code, IMPACT.

The conference was aimed at early career physicists who were interested in exploring the possibilities of working at the interface between physics and biology, in particular, graduate students and postdocs considering applying the methods of physics to biological research. Areas of major importance were genomics and evolution, biological networks, biomolecular dynamics, high-resolution imaging of living cells, and technologies for biological investigation. A total of 205 persons attended the conference.

The structure of a completely amorphous zircon was determined by time-of-flight neutron diffraction at Argonne's Intense Pulsed Neutron Source (IPNS). The sample of metamict zircon (ZrSiO{sub 4}),initially doped to 8.85 weight percent {sup 238}Pi, had been completely amorphized by alpha-recoil damage since its synthesis in 1981 at the Pacific Northwest National Laboratory (PNNL). The measured diffraction structure factor, S(Q), indicated a completely amorphous sample, with no signs of residual zircon microcrystallinity. The pair distribution function obtained indicated that the structure was that of an oxide glass, retaining the Si-0, Zr-0, and O-O bond lengths of crystalline zircon.

At an international conference on global warming, held in Kyoto, Japan, in December 1997, the United States committed to reduce its greenhouse gas (GHG) emissions by 7% over its 1990 level by the year 2012. To help achieve that goal, transportation GHG emissions need to be reduced. Using Argonne's fuel-cycle model, I estimated GHG emissions reduction potentials of various near- and long-term transportation technologies. The estimated per-mile GHG emissions results show that alternative transportation fuels and advanced vehicle technologies can help significantly reduce transportation GHG emissions. Of the near-term technologies evaluated in this study, electric vehicles; hybrid electric vehicles; compression-ignition, direct-injection vehicles; and E85 flexible fuel vehicles can reduce fuel-cycle GHG emissions by more than 25%, on the fuel-cycle basis. Electric vehicles powered by electricity generated primarily from nuclear and renewable sources can reduce GHG emissions by 80%. Other alternative fuels, such as compressed natural gas and liquefied petroleum gas, offer limited, but positive, GHG emission reduction benefits. Among the long-term technologies evaluated in this study, conventional spark ignition and compression ignition engines powered by alternative fuels and gasoline- and diesel-powered advanced vehicles can reduce GHG emissions by 10% to 30%. Ethanol dedicated vehicles, electric vehicles, hybrid electric vehicles, and …

Microstructural evolution due to aging of solder alloys determines their long-term reliability as electrical, mechanical and thermal interconnects in electronics packages. The ability to accurately determine the reliability of existing electronic components as well as to predict the performance of proposed designs depends upon the development of reliable material models. A kinetic Monte Carlo simulation was used to simulate microstructural evolution in solder-class materials. The grain growth model simulated many of the microstructural features observed experimentally in 63Sn-37Pb, a popular near-eutectic solder alloy. The model was validated by comparing simulation results to new experimental data on coarsening of Sn-Pb solder. The computational and experimental grain growth exponent for two-phase solder was found to be much lower than that for normal, single phase grain growth. The grain size distributions of solders obtained from simulations were narrower than that of normal grain growth. It was found that the phase composition of solder is important in determining grain growth behavior.

The Self-Describing Data Sets (SDDS) toolkit comprises about 70 generally-applicable programs sharing a common data protocol. At the Advanced Photon Source (APS), SDDS performs the vast majority of operational data collection and processing, most data display functions, and many control functions. In addition, a number of accelerator simulation codes use SDDS for all post-processing and data display. This has three principle advantages: first, simulation codes need not provide customized post-processing tools, thus simplifying development and maintenance. Second, users can enhance code capabilities without changing the code itself, by adding SDDS-based pre- and post-processing. Third, multiple codes can be used together more easily, by employing SDDS for data transfer and adaptation. Given its broad applicability, the SDDS file protocol is surprisingly simple, making it quite easy for simulations to generate SDDS-compliant data. This paper discusses the philosophy behind SDDS, contrasting it with some recent trends, and outlines the capabilities of the toolkit. The paper also gives examples of using SDDS for accelerator simulation.

A fundamental concern in the design of the potential repository at Yucca Mountain. Nevada is the response of the host rock to the emplacement of heat-generating waste. The thermal perturbation of the rock mass has implications regarding the structural, hydrologic. and geochemical performance of the potential repository. The phenomenological coupling of many of these performance aspects makes repository thermal modeling a difficult task. For many of the more complex, coupled models, it is often necessary to reduce the geometry of the potential repository to a smeared heat-source approximation. Such simplifications have impacts on induced thermal profiles that in turn may influence other predicted responses through one- or two-way thermal couplings. The effect of waste employment layout on host-rock thermal was chosen as the primary emphasis of this study. Using a consistent set of modeling and input assumptions, far-field thermal response predictions made for discrete-source as well as plate source approximations of the repository geometry. Input values used in the simulations are consistent with a design-basis a real power density (APD) of 80 kW/acre as would be achieved assuming a 2010 emplacement start date, a levelized receipt schedule, and a limitation on available area as published in previous design studies. It …

Argonne National Laboratory is developing an electrometallurgical treatment for spent fuel from the experimental breeder reactor II. A product of this treatment process is a metal waste form that incorporates the stainless steel cladding hulls, zirconium from the fuel and the fission products that are noble to the process, i.e., Tc, Ru, Pd, Rh, Ag. The nominal composition of this waste form is stainless steel/15 wt% zirconium 1-4 wt% noble metal fission products. The behavior of technetium is of particular importance from a disposal point of view for this waste form due to its long half life, 2. 14E5 years, and its mobility in groundwater. To address these concerns a limited number of spiked metal waste forms were produced containing Tc. These surrogate waste forms were then studied using scanning electron microscopy and selected leaching tests.

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The current knowledge is reviewed on (1) the effects of neutron irradiation on tensile strength and ductility, ductile-brittle transition temperature, creep, fatigue, and swelling of vanadium-base alloys, (2) the compatibility of vanadium-base alloys with liquid lithium, water, and helium environments, and (3) the effects of hydrogen and helium on the physical and mechanical properties of vanadium alloys that are potential candidates for structural materials applications in fusion systems. Also, physical and mechanical properties issues are identified that have not been adequately investigated in order to qualify a vanadium-base alloy for the structural material in experimental fusion devices and/or in fusion reactors.

The diffusivity in alloys at low temperatures is modeled for composition-modulated structures using Khachaturyan's microscopic theory of diffusion. The theory is now applied to assess a two-phase multilayer system.