A microfluidic switch has been demonstrated using an AC Magnetohydrodynamic (MHD) pumping mechanism in which the Lorentz force is used to pump an electrolytic solution. By integrating two AC MHD pumps into different arms of a Y-shaped fluidic circuit, flow can be switched between the two arms. This type of switch can be used to produce complex fluidic routing, which may have multiple applications in {micro}TAS.

The effects of varying the input for the CAP88PC Version 2.0 program on the total effective dose equivalents (TEDEs) were determined for hypothetical releases from the Hot Fuel Examination Facility (HFEF) located at the Argonne National Laboratory site on the Idaho National Engineering and Environmental Laboratory (INEEL). Values for site specific meteorological conditions and agricultural production parameters were determined for the 80 km radius surrounding the HFEF. Four nuclides, {sup 3}H, {sup 85}Kr, {sup 129}I, and {sup 137}Cs (with its short lived progeny, {sup 137m}Ba) were selected for this study; these are the radioactive materials most likely to be released from HFEF under normal or abnormal operating conditions. Use of site specific meteorological parameters of annual precipitation, average temperature, and the height of the inversion layer decreased the TEDE from {sup 137}Cs-{sup 137m}Ba up to 36%; reductions for other nuclides were less than 3%. Use of the site specific agricultural parameters reduced TEDE values between 7% and 49%, depending on the nuclide. Reductions are associated with decreased committed effective dose equivalents (CEDEs) from the ingestion pathway. This is not surprising since the HFEF is located well within the INEEL exclusion area, and the surrounding area closest to the release point …

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Initial dislocation structure in annealed high-purity Mo single crystals and deformation substructure in a crystal subjected to 1% compression have been examined and studied using transmission electron microscopy (TEM) techniques in order to investigate dislocation multiplication mechanisms in the early stage of plastic deformation. The initial dislocation density is in a range of 10{sup 6} {approx} 10{sup 7} cm{sup -2}, and the dislocation structure is found to contain many grown-in superjogs along dislocation lines. The dislocation density increases to a range of 10{sup 8} {approx} 10{sup 9} cm{sup -2}, and the average jog height is also found to increase after compressing for a total strain of 1%. It is proposed that the preexisting jogged screw dislocations can act as (multiple) dislocation multiplication sources when deformed under quasi-static conditions. The jog height can increase by stress-induced jog coalescence, which takes place via the lateral migration (drift) of superjogs driven by unbalanced line-tension partials acting on link segments of unequal lengths. The coalescence of superjogs results in an increase of both link length and jog height. Applied shear stress begins to push each link segment to precede dislocation multiplication when link length and jog height are greater than critical lengths. This ''dynamic'' …

Records Managers are continually exploring ways to integrate their services with those offered by Information Technology-related professions to capitalize on the advantages of providing customers a total solution to managing their records and information. In this day and age, where technology abounds, there often exists a fear on the part of records management that this integration will result in a loss of identity and the focus of one's own mission - a fear that records management may become subordinated to the fast-paced technology fields. They need to remember there is strength in numbers and it benefits RM, IT, and the customer when they can bring together the unique offerings each possess to reach synergy for the benefit of all the corporations. Records Managers, need to continually strive to move ''outside the records management box'', network, expand their knowledge, and influence the IT disciplines to incorporate the concept of ''management'' into their customer solutions.

Laboratory facilities have made great strides in producing large sets of reliable data for X-ray astronomy, which include ionization and recombination cross sections needed for charge balance calculations as well as the atomic data needed for interpreting X-ray line formation. We discuss data from the new generation sources and pay special attention to the LLNL electron beam ion trap experiment, which is unique in it's ability to provide direct laboratory access to spectral data under precisely controlled conditions that simulate those found in many astrophysical plasmas. Examples of spectral data obtained in the 1-160 A wavelength range are given illustrating the type of laboratory X-ray data produced in support of such missions as Chandra, XMM, ASCA and EUVE.

The longevity of high gain GaAs photoconductive semiconductor switches (PCSS) has been extended to over 100 million pulses at 23A, and over 100 pulses at 1kA. This is achieved by improving the ohmic contacts by doping the semi-insulating GaAs underneath the metal, and by achieving a more uniform distribution of contact wear across the entire switch by distributing the trigger light to form multiple filaments. This paper will compare various approaches to doping the contacts, including ion implantation, thermal diffusion, and epitaxial growth. The device characterization also includes examination of the filament behavior using open-shutter, infra-red imaging during high gain switching. These techniques provide information on the filament carrier densities as well as the influence that the different contact structures and trigger light distributions have on the distribution of the current in the devices. This information is guiding the continuing refinement of contact structures and geometries for further improvements in switch longevity.

Particulate emissions from spark-ignited (SI) engines have come under close scrutiny as they tend to be smaller than 50 nm, are composed mainly of volatile organic compounds, and are emitted in significant numbers. To assess the impact of such emissions, measurements were performed in the exhaust of a current-technology port-fuel-injected SI engine, which was operated at various steady-state conditions. To gain further insights into the particulate formation mechanisms, measurements were also performed upstream of the catalytic converter. At all engine speeds, a general trend was observed in the number densities and mass concentrations: a moderate increase at low loads followed by a decrease at mid-range loads, which was followed by a steep increase at high loads. Within reasonable bounds, one could attribute such a trend to three different mechanisms. An unidentified mechanism at low loads results in particulate emissions monotonically increasing with load. At medium loads, wherein the engine operates close to stoichiometric conditions, high exhaust temperatures lead to particulate oxidation. At high loads, combustion occurs mostly under fuel-rich conditions, and the contribution from combustion soot becomes significant. Estimates of the number of particles emitted per kilometer by a vehicle carrying the current test engine were found to be lower …

Radionuclide transport in soils and groundwaters is routinely calculated in performance assessment (PA) codes using simplified conceptual models for radionuclide sorption, such as the K{sub D} approach for linear and reversible sorption. Model inaccuracies are typically addressed by adding layers of conservativeness (e.g., very low K{sub D}'s), and often result in failed transport predictions or substantial increases in site cleanup costs. Realistic assessments of radionuclide transport over a wide range of environmental conditions can proceed only from accurate, mechanistic models of the sorption process. They have focused on the sorption mechanisms and partition coefficients for Cs{sup +}, Sr{sup 2+} and Ba{sup 2+} (analogue for Ra{sup 2+}) onto iron oxides and clay minerals using an integrated approach that includes computer simulations, sorption/desorption measurements, and synchrotron analyses of metal sorbed substrates under geochemically realistic conditions. Sorption of Ba{sup 2+} and Sr{sup 2+} onto smectite is strong, pH-independent, and fully reversible, suggesting that cation exchange at the interlayer basal sites controls the sorption process. Sr{sup 2+} sorbs weakly onto geothite and quartz, and is pH-dependent. Sr{sup 2+} sorption onto a mixture of smectite and goethite, however, is pH- and concentration dependent. The adsorption capacity of montmorillonite is higher than that of goethite, which …

Preliminary measurements with high energy x-rays from the SRI CAT 1-ID beam line at the Advanced Photon show great promise for the measurement of stress and strain using diffraction. Comparisons are made with neutron measurements. Measurements of strains in a 2 mm thick 304 stainless steel weld show that excellent strain and spatial resolutions are possible. With 200 {micro}m slits, strain resolutions of 1 x 10{sup {minus}5} were achieved.

Phase I of Boeing Company/DOE Dish Engine Critical Component (DECC) Project started in April of 1998 and was completed in 1999. The Phase I objectives, schedule, and test results are presented in this paper. These data shows the power, energy, and mirror performance are comparable to that when the hardware was first manufactured 15 years ago. During the Phase I and initial Phase II test period the on-sun system accumulated over 3,800 hours of solar-powered operating time, accumulated over 4,500 hours of concentrator solar tracking time, and generated over 50,000 kWh of grid-compatible electrical energy. The data also shows that the system was available 95 {percent} of the time when the sun's insolation level was above approximately 300 w/m{sup 2}, and achieved a daily energy efficiency between 20{percent} and 26{percent}. A second concentrator was refurbished during Phase I and accumulated over 2,200 hours of solar track time. A second Stirling engine operated 24 hours a day in a test cell in Sweden and accumulated over 6,000 test hours. Discussion of daily operation shows no major problems encountered during the testing that would prevent commercialization of the technology. Further analysis of the test data shows that system servicing with hydrogen, coolant …

The Intelligent Systems and Robotics Center (ISRC) at Sandia National Laboratories (SNL) is developing technologies for glovebox size reduction in the DOE nuclear complex. A study was performed for Kaiser-Hill (KH) at the Rocky Flats Environmental Technology Site (RFETS) on the available technologies for size reducing the glovebox lines that require size reduction in place. Currently, the baseline approach to these glovebox lines is manual operations using conventional mechanical cutting methods. The study has been completed and resulted in a concept of the robotic system for in-situ size reduction. The concept makes use of commercially available robots that are used in the automotive industry. The commercially available industrial robots provide high reliability and availability that are required for environmental remediation in the DOE complex. Additionally, the costs of commercial robots are about one-fourth that of the custom made robots for environmental remediation. The reason for the lower costs and the higher reliability is that there are thousands of commercial robots made annually, whereas there are only a few custom robots made for environmental remediation every year. This paper will describe the engineering analysis approach used in the design of the robotic system for glovebox size reduction.

Solar Two, a 10MWe power tower plant in Barstow, California, successfully demonstrated the production of grid electricity at utility-scale with a molten-salt solar power tower. This paper provides an overview of the project, from inception in 1993 to closure in the spring of 1999. Included are discussions of the goals of the Solar Two consortium, the planned-vs.-actual timeline, plant performance, problems encountered, and highlights and successes of the project. The paper concludes with a number of key results of the Solar Two test and evaluation program.

Solar power towers, based on molten salt technology, have been the subject of extensive research and development since the late 1970s. In the mid 1980s, small experimental plants were successfully fielded in the USA and France that demonstrated the feasibility of the concept at a 1 to 2 MW{sub e} scale. Systems analyses indicate this technology will be cost competitive with coal-fired power plants after scaling-up plant size to the 100 to 200 MW{sub e} range. To help bridge the scale-up gap, a 10 MW{sub e} demonstration project known as Solar Two, was successfully operated in California, USA from 1996 to 1999. The next logical step could be to scale-up further and develop a 30 MW{sub e} project within the country of Mexico. The plant could be built by an IPP industrial consortium consisting of USA's Boeing and Bechtel Corporations, combined with Mexican industrial and financial partners. Plausible technical and financial characteristics of such a ``Solar-Two-type'' Mexican project are discussed in this paper.

The focus of this work is the structure within highly crosslinked, two component epoxy films. The authors examine variations in crosslink density within thin epoxy films on silicon substrates by solvent swelling. The method is based on the fact that the equilibrium volume fraction of a swelling solvent is strongly dependent upon the local crosslink density. The authors examine the volume fraction profile of the good solvent nitrobenzene through the epoxy films by neutron reflection. Isotopic substitution is used to provide contrast between the epoxy matrix and the swelling solvent.

The relationship between the nature and spatial distribution of fundamental interfacial interactions and fracture stress/fracture toughness of a glassy adhesive-inorganic solid joint is not understood. This relationship is important from the standpoint of designing interfacial chemistry sufficient to provide the level of mechanical strength required for a particular application. In addition, it is also important for understanding the effects of surface contamination. Different types of contamination, or different levels of contamination, likely impact joint strength in different ways. Furthermore, the relationship is also important from the standpoint of aging. If interfacial chemical bonds scission over time due to the presence of a contaminant such as water, or exposure to UV, etc, the relationship between joint strength/fracture toughness and interface strength is important for predicting reliability with time. A fundamental understanding of the relationship between joint strength and fundamental interfacial interactions will give insight into these issues.