In this paper, the authors report on a diode-side-pumped Er:YAG laser that generates over 500 mW of average power at 2.94 {mu}m, and tunes over a 6 nm range centered about the 2.94-{mu}m transition. Prior to the development of the laser, diode-pumped Er:YAG lasers have been end-pumped monolithic devices that deliver {approximately}200 mW of output at 2.94 {mu}m. Much of the difficulty in obtaining higher average power from Er:YAG stems from the unfavorable lifetimes of the upper and lower laser levels, the complex state dynamics, and a low stimulated emission cross section ({sigma} {approx} 3 {times} 10{sup {minus}20} cm{sup 2}). One of the most important dynamical processes in Er:YAG is cross relaxation between neighboring Er{sup 3+} ions in the {sup 4}I{sub 13/2} level. By recycling much of the {sup 4}I{sub 13/2} population (lower laser level) into {sup 4}I{sub 11/2} (upper laser level), the cross relaxation overcomes the unfavorable lifetimes of the two levels, allowing the population inversion to be sustained. It is this cross relaxation along with thermalization of the two laser levels that allows cw oscillation on the 2.94 {mu}m line to take place. The laser that they describe here is a quasi-cw device as the approach to obtaining …

The Hanford Site began operations in 1943 as one of the sites for plutonium production associated with the Manhattan Project. It has been used, in part, for nuclear reactor operation, reprocessing of spent fuel, and management of radioactive waste. The Hanford Site covers approximately 1,434 km{sup 2} (560 mi{sup 2}2) in southeastern Washington State. The subject of this paper, the 618-9 Burial Ground, is located on the Hanford Site approximately 1.6 km (1 mi) west of the Columbia River, and a few miles north of Richland, Washington. Throughout Hanford Site history, prior to legislation regarding disposal of chemical waste products, some chemical waste byproducts were disposed ,ia burial in trenches. One such trench was the 618-9 Burial Ground. This burial ground was suspected to contain approximately 19,000 L (5,000 gal) of uranium-contaminated organic solvent, disposed in standard 55-gal (208-L) metal drums. The waste was produced from research and development activities related to fuel reprocessing.

The Hanford Site has over 100 facilities that have been declared surplus and are scheduled to be decommissioned. In addition to these surplus facilities, there is a significant number of facilities that are currently being shut down, deactivated, and transferred to the Decontamination and Decommissioning (D&D) program. In the last year, Westinghouse Hanford Company and the US Department of Energy, Richland Operations Office, have developed and implemented an initiative to accelerate the D&D work at the Hanford Site. The strategy associated with accelerated D&D is to reduce the number of surplus facilities, eliminate potential safety hazards, demonstrate meaningful cleanup progress, and recycle materials for other uses. This initiative has been extremely successful and has resulted in the safe demolition of 13 facilities in fiscal year (FY) 1993. In addition, four facilities have been completed in FY 1994 and demolition of several other facilities is currently underway.

Under certain conditions, the separation of actinides using electromechanical techniques may be an effective means of residue processing. The separation of granular mixtures of actinides and other materials discussed in this report is based on appreciable differences in the magnetic and electrical properties of the actinide elements. In addition, the high density of actinides, particularly uranium and plutonium, may render a simultaneous separation based on mutually complementary parameters. Both high intensity magnetic separation and electrostatic separation have been investigated for the concentration of an actinide waste stream. Waste stream constituents include an actinide metal alloy and broken quartz shards. The investigation of these techniques is in support of the Integral Fast Reactor (IFR) concept currently being developed at Argonne National Laboratory under the auspices of the Department of Energy.

The objective of the planned research in advanced tokamak development on DIII-D at General Atomics, San Diego, USA. is to establish improved tokamak operation through significant improvements in the stability factor, confinement quality, and bootstrap current fraction using localized radio frequency (rf) current profile control, rf and neutral beam heating for pressure profile control, as well as control of plasma rotation and optimization of the plasma boundary conditions. Recent research results in H-mode confinement, modifications of current profiles to achieve higher confinement and higher {beta}, a new regime of improved confinement (VH-mode), and rf noninductive current drive are encouraging. In this talk, arguments will be presented supporting the need for improved performance in tokamak reactors. Experimentally observed advanced performance regimes on DIII-D will be discussed. Confinement improvement up to H = 4, where H is the ratio of energy confinement time to the ITER89-P scaling H{triple_bond} {Tau}{sub E}/{Tau}{sub E-ITER89-P}, has been achieved. In other discharges {beta}{sub N} = {beta}/(I/aB),[%-m{center_dot}{Tau}/MA] {approx_gt} 6 has been obtained. These values have so far been achieved transiently and independently. Techniques, will be described which can extend the high performance to quasi-steady-state and sustain the high H and {beta}{sub N} values simultaneously. Two high performance regimes, …

Routine, automated solar radiometry observations began with the development of the Mobile Automated Scanning Photometer (MASP) and its installation at the Rattlesnake Mountain Observatory (RMO). We have introduced a microprocessor controlled rotating shadowband radiometer (RSR), both the single detector and the multi-filter/detector (MFRSR) versions to replace the MASP. The operational mode of the RSRs is substantially different than the MASP or other traditional sun-tracking radiometers, because, by virtue of the automated rotating shadowband, the total and diffuse irradiance on a horizontal plane are measured and the direct-normal component deduced through computation from the total and diffuse components by the self-contained microprocessor. Because the three irradiance components are measured using the same detector for a given wavelength, the calibration coefficients are identical for each component, thus reducing errors when comparing them. The MFRSR is the primary radiometric instrument in the nine-station Quantitative Links Network (QLN) established in the eastern United States in late 1991. Data from this network are being used to investigate how cloud- and aerosol-induced radiative effects vary in time and with cloud structure and type over a mid-latitude continental region. This work supports the DOE Quantitative Links Program to quantify linkages between changes in atmospheric composition and climate …

An aerosol model was developed for a radioactive waste tank vapor space and ventilation system. The source of aerosol formation was modeled from gas bubble bursts at the liquid surface. The gases contained in these bubbles are formed by radiolytic breakdown of liquid and organic materials in the radioactive tank contents. The model accounts for the rate of radiolytic gas formation and the rate of tank liquids that are released as aerosols. The concentration of particles in the tank vapor are modeled as a function of the deposition rate of dry particles and the vapor removal rate by ventilation. The ventilation rate in tanks without an active ventilation system has a threshold level that is driven by atmospheric pressure variation. The model predictions are compared to measurements in several typical waste tank vapors of the Hanford Site waste storage tanks.

The Human-Specific (HS) subfamily of Alu sequences is comprised of a group of 500 nearly identical members which are almost exclusively restricted to the human genome. Individual subfamily members share an average of 98.9% nucleotide identity with the HS subfamily consensus sequence, and have an average age of 2.8 million years. We have developed a Polymerase Chain Reaction (PCR) based assay using primers complementary to the 5 inch and 3 inch unique flanking DNA sequences from each HS Alu that allow the locus to be assayed for the presence or absence of the Alu repeat. The dimorphic HS Alu sequences probably inserted in the human genome after the radiation of modem humans (within the last 200,000-one million years) and represent a unique source of information for human population genetics and forensic DNA analyses. These sites can be developed into Dimorphic Alu Sequence Tagged Sites (DASTS) for the Human Genome Project. HS Alu family member insertions differ from other types of polymorphism (e.g. Variable Number of Tandem Repeat [VNTR] or Restriction Fragment Length Polymorphism [RFLP]) in that polymorphisms due to Alu insertions arise as a result of a unique event which has occurred only one time in the human population and …

The development of liquid metal reactor concepts with passive safety characteristics is in progress at the General Electric Company under contract to the US Department of Energy. To assess the performance of these systems under postulated severe accident conditions analyses of containment accidents relating to the breach of the primary coolant boundary of the Department of Energy Advanced Liquid Metal Reactor were completed by Westinghouse Hanford Company for the plant designer General Electric. A series of three accident cases were selected by General Electric for characterizing the containment responding to a hypothetical core disruptive accident. In addition, the Advanced Liquid Metal Reactor Steam Generator Building was also analyzed to demonstrate the acceptability of the Steam Generator Building sodium fire protection strategy related to a design-basis leak.

The fluid and particle dynamics of a High Velocity Oxygen-Fuel (HVOF) torch are analyzed using computational fluid dynamic (CFD) techniques. The thermal spray device analyzed is similar to a Metco Diamond Jet torch with powder injection. The spray nozzle is axisymmetric with powder injection on the centerline, premixed fuel and oxygen fed from an annulus, and air cooling injected along the interior surface of the aircap. Choked flow conditions occur at the exit of the aircap and a supersonic, under-expanded jet develops externally. The CFD simulation assumes three injection streams (solid metal particles with argon as a carrier gas, premixed oxygen/fuel, and air) inside the aircap and solves the combusting two-phase flow until the external spray stream decays to sonic conditions. The numerical formulation solves the mass, momentum, and energy transfer for both the gas and particle phase and strongly couples each phase. The combustion process is modeled using approximate equilibrium chemistry with dissociation of the gas with a total of nine species. Melting and re-solidification of the metal panicles is modeled as a lumped-mass system. Turbulent flow is modeled by a two equation k-{epsilon} turbulence model, including compressibility effects on turbulent dissipation. A time iterative, implicit, finite volume numerical …

The US Department of Energy sponsored several student engineering competitions in 1993 that provided useful information on electric and hybrid electric vehicles. The electrical energy usage from these competitions has been recorded with a custom-built digital meter installed in every vehicle and used under controlled conditions. When combined with other factors, such as vehicle mass, speed, distance traveled, battery type, and type of components, this information provides useful insight into the performance characteristics of electrics and hybrids. All the vehicles tested were either electric vehicles or hybrid vehicles in electric-only mode, and had an average energy economy of 7.0 km/kwh. Based on the performance of the ``ground-up`` hybrid electric vehicles in the 1993 Hybrid Electric Vehicle Challenge, data revealed a I km/kwh energy economy benefit for every 133 kg decrease in vehicle mass. By running all the electric vehicles at a competition in Atlanta at several different constant speeds, the effects of rolling resistance and aerodynamic drag were evaluated. On average, these vehicles were 32% more energy efficient at 40 km/h than at 72 km/h. The results of the competition data analysis confirm that these engineering competitions not only provide an educational experience for the students, but also show technology …

Angle interferometers are commonly used to measure surface plate flatness. An error can exist when the centerline of the double comer cube mirror assembly is not square to the surface plate and the guide bar for the mirror sled is curved. Typical errors can be one to two microns per meter. A similar error can exist in the calibration of rotary tables when the centerline of the double comer cube mirror assembly is not square to the axes of rotation of the angle calibrator and the calibrator axis is not parallel to the rotary table axis. Commercial double comer cube assemblies typically have non-parallelism errors of ten milli-radians between their centerlines and their sides and similar values for non-squareness between their centerlines and end surfaces. The authors have developed a simple method for measuring these errors and correcting them by remachining the reference surfaces.

Application of multipoint statistics to the analysis of sprays and other particle flows is extended in order to encompass third- and higher-order statistical information. Relation between data taken from (e.g.) phase Doppler measurements of particle arrival times and intensity function which represents a particle flow are investigated. It is shown that, at any order, the distribution of all gaps between particle arrival times has a more direct relation to the correlation functions which characterize the flow than does the distribution of sequential interparticle times. Moments of the intensity distribution are expressed in terms of the behavior of the distributions for small interparticle gaps. Examples of stochastic intensity functions are given to illustrate the significance of differences in higher-order correlations.

Over the past several years, molecular modeling has been applied to study various characteristics of coal molecular structures. Powerful workstations coupled with molecular force-field-based software packages have been used to study coal and coal-related molecules. Early work involved determination of the minimum-energy three-dimensional conformations of various published coal structures (Given, Wiser, Solomon and Shinn), and the dominant role of van der Waals and hydrogen bonding forces in defining the energy-minimized structures. These studies have been extended to explore various physical properties of coal structures, including density, microporosity, surface area, and fractal dimension. Other studies have related structural characteristics to cross-link density and have explored small molecule interactions with coal. Finally, recent studies using a structural elucidation (molecular builder) technique have constructed statistically diverse coal structures based on quantitative and qualitative data on coal and its decomposition products. This technique is also being applied to study coalification processes based on postulated coalification chemistry.

This paper brings into focus the results of numerous studies that have addressed issues associated with the validity of assumptions which are used to justify reducing the dimensionality of numerical calculations of water flow through Yucca Mountain, NV. It is shown that in many cases, one-dimensional modeling is more rigorous than previously assumed.

In May 1992 the Department of Energy`s Atmospheric Radiation Measurement (ARM) Program began deploying instrumentation and conducting measurements at its first field site near Lamont in North Central Oklahoma. ARM is a major program of atomospheric measurement and modeling intended to improve understanding of the processes and properties that affect atmospheric radiation. Particular emphasis is being placed on the role of clouds in radiative transport and on improving the representation of clouds and cloud radiative properties in climate models. In this paper we provide a brief overview of the ARM Program. We discuss the philosophy behind the ARM experiment design, describe the types of experiments underway and their objectives, and we portray how the suite of instrumentation and the observational strategy is expected to evolve as the process of experiment design, hypothesis testing, and learning plays out over the next decade.

A magazine article pertaining to the athletes participating at the Gay Games. The right side is highlighted with an arrow pointing at the cheerleading paragraph.

It is generally believed that many properties of solid interfaces are ultimately determined by their structure and composition at the atomic level. We report here on work in two areas of grain boundary (GB) research in which structure-property correlations have been investigated recently. HREM observations in connection with computer modeling of GBs in fcc metals have given considerable insight into correlations between GB energy and atomic-scale GB structure. Efforts to understand and possibly control the supercurrent transport behavior across GBs in high-temperature superconductors require the combination of microstructure characterizations with investigations of electric transport properties. In both areas considerable progress is being made and has already lead to important insights concerning interfacial properties.

Measurements of the average b-hadron lifetime using inclusive B {yields} J/{psi}X events, the individual B{sub u} and B{sub d} lifetimes and their ratio using exclusive B {yields} {psi}K events, and the B{sub s} lifetime using semileptonic B{sub s} lifetime using semileptonic B{sub s} {yields} l{nu}D{sub 3}X events are presented. The results were obtained from a 21.3 pb{sup {minus}1} sample of {radical}s = 1.8 TeV {bar p}p collisions collected in 1992--93 at the Fermilab Tevatron collider and required the precise position measurements of the recently installed CDF silicon vertex detector.

The production of b quarks in p{bar p} collisions is studied in the Collider Detector at Fermilab (CDF), using the B meson decay channels B{sup +} {yields} J/{psi}K{sup +} and B{sup 0} {yields} J/{psi}K*{sup 0}, with J/{psi} {yields} {mu}{sup +}{mu}{sup {minus}} and K*{sup 0} {yields} K{sup +}{pi}{sup {minus}}, and their charge conjugates. Measurements of the B meson and b quark cross-sections integrated above minimum transverse momentum values in the rapidity range {vert_bar}y{vert_bar} < 1 are described. The first fully differential B meson cross-section measurement, in the same rapidity range, is also reported. Comparison is made to the O({alpha}{sub s}{sup 3}) theoretical calculations.

This report discusses the beam dynamics of the booster; transition crossing of the main ring; coupled-bunch instability; and snap coalescence.

In the effort to evaluate boron-rich coatings as plasma facing surfaces in fusion devices, a new process for applying boron carbide (B{sub 4}C) coatings to graphite was developed. The process entails eutectic melting of the carbon (C) substrate surface with a precursor layer of B{sub 4}C particles. Adherent coatings were achieved which consisted of two layers: a surface layer and a graded penetration zone in the outer portion of the substrate. The surface-layer microstructure was multiphase and ranged from reaction-sintered structures of sintered B{sub 4}C particles in an eutectic-formed matrix to that of hypereutectic carbon particles in a B{sub 4}C-C eutectic matrix. Because of high surface energy, the coating generally developed a nonuniform thickness. Quantitative evaluations of the coating were performed with limiters in the TEXTOR fusion device and with coupons in electron beam tests. Test results revealed the following: good adherence of the coating even after remelting; and, during remelting, diagnostics detected a corresponding interaction of boron with the plasma.

Risk assessment is a quantitative evaluation of information on potential health hazards of environmental contaminants and the extent of human exposure to these contaminants. As applied to toxic chemical emissions to air, risk assessment involves four interrelated steps. These are (1) determination of source concentrations or emission characteristics, (2) exposure assessment, (3) toxicity assessment, and (4) risk characterization. These steps can be carried out with assistance from analytical models in order to estimate the potential risk associated with existing and future releases. CAirTOX has been developed as a spreadsheet model to assist in making these types of calculations. CAirTOX follows an approach that has been incorporated into the CalTOX model, which was developed for the California Department of Toxic Substances Control, With CAirTOX, we can address how contaminants released to an air basin can lead to contamination of soil, food, surface water, and sediments. The modeling effort includes a multimedia transport and transformation model, exposure scenario models, and efforts to quantify uncertainty in multimedia, multiple-pathway exposure assessments. The capacity to explicitly address uncertainty has been incorporated into the model in two ways. First, the spreadsheet form of the model makes it compatible with Monte-Carlo add-on programs that are available for …

Article discussing research on the calculation of methane C-H oxidative addition trajectory and a comparison to experiment and methane activation by high-valent complexes.