Microstructurally-induced changes in the local stress state (triaxial constraint) and their effect on fracture-toughness behavior are examined at ambient and cryogenic temperatures in an Al-Li-Cu-Zr alloy, processed in the form of 12.7 mm-thick naturally laminated'' plate containing aligned-weak interfaces and 1.6 mm-thin unlaminated sheet. It is shown that marked improvements in long-transverse (L-T) toughness can be achieved in the plate material at cryogenic temperatures by promoting through-thickness delamination along these interfaces, which relaxes local constraint and promotes a fracture-mode transition from global plane strain to local plane stress. Conversely, in thin sheet material, the absence of such interface delamination leads to a reduction in toughness with decrease in temperature, consistent with the greater degree of crack-tip constraint. 17 refs., 4 figs., 1 tab.

Fatigue-crack propagation behavior in powder-metallurgy (P/M) aluminum-lithium alloys, namely, mechanically-alloyed (MA) Al-4.0Mg-1.5Li-1.1C-0.80{sub 2} (Inco 905-XL) and rapid-solidification-processed (RSP) Al-2.6Li-1.0Cu-0.5Mg-0.5Zr (Allied 644-B) extrusions, has been studied, and results compared with data on an equivalent ingot-metallurgy (I/M) Al-Li alloy, 2090-T81 plate. Fatigue-crack growth resistance of the RSP Al-Li alloy is found to be comparable to the I/M Al-Li alloy; in contrast, crack velocities in MA 905-XL extrusions are nearly three orders of magnitude faster. Growth-rate response in both P/M Al-Li alloys, however, is high anisotropic. Results are interpreted in terms of the microstructural influence of strengthening mechanism, slip mode, grain morphology and texture on the development of crack-tip shielding from crack-path deflection and crack closure. 14 refs., 7 figs., 2 tabs.

Value Engineering is an organized problem solving technique that utilizes communication and teamwork skills -- skills heralded as strengths for women. Value Engineering offers an excellent career opportunity for women in the engineering profession. It is an expanded career path that is currently being overlooked by women. Value Engineering is supported by SAVE (Society of American Value Engineers) and certification in the process can be achieved in two years. For women in the engineering profession, VE is an ideal place to redirect their existing skills and training. The number of certified women is a minority, creating a wide-open field of opportunity in federal and state agencies as well as private industry. Value Engineering can provide that new avenue for engineering careers -- a new direction where current skills can be applied to a diverse and exciting profession. 1 fig.

In situ vitrification (ISV) is a thermal treatment process that converts contaminated soil into a durable, leach-resistant product similar to obsidian or basalt. The process, which was developed by Pacific Northwest Laboratory (PNL) for remediation of contaminated soil, is now in the field demonstration and implementation stage. Demonstration tests using the US Department of Energy (DOE)-owned large-scale system are underweight or planned for applications at Hanford and other DOE sites, including the Idaho National Engineering Laboratory, Oak Ridge National Laboratory, and the Savannah River Site. In addition, a private company, Geosafe Corporation, is beginning remediation of commercial contaminated soil sites. A mathematical and computer model has been developed at PNL as a predictive tool to assist engineers and researchers in the application of ISV to different sites. The model, currently configured on a Macintosh personal computer, predicts vitrification time, depth, width, and electrical consumption based on user inputs of electrode configuration, soil parameters, and molten glass characteristics. The model time and depth predications are useful for operations planning, cost estimates, and site selection. Additionally, the depth and width predictions will be used to direct ISV operations to ensure that the contaminated area is completely vitrified and to help mitigate the …

Multilayer structures of W/C, WC/C, and Ru/C, of various periods were prepared and studied by high-resolution transmission electron microscopy. Comparison of the phases in the layered structures is made for as-prepared and annealed samples. Both as-prepared and annealed WC/C multilayers are predominantly amorphous, while the phases in the W/C depend on the periods. The 2 nm period W/C multilayer remains amorphous after annealing, and the longer periods recrystallize to form W{sub 2}C. The layered microstructures of W/C and WC/C are stable on annealing at all periods, while the amorphous Ru-rich layers in the 2 nm period Ru/C multilayer agglomerate upon annealing to form elemental hexagonal Ru crystallites. Larger period Ru/C multilayers show stable layered structures, and indicate hexagonal Ru in the Ru-rich layers. X-ray measurements show that the multilayer periods expand on annealing for all metal-carbon multilayers studied. 15 refs., 5 figs., 1 tab.

Alloys with reduced long-life radioactivity (low activation alloys) are being developed to increase the acceptability of fusion power. The phase stability and swelling resistance of a 12Cr-6.5Mn-1W-0.3V-0.1C martensitic steel were evaluated by transmission electron microscopy following 3.8 MeV Fe{sup ++} ion irradiation with and without He coimplantation. Ion irradiations were performed at 450{degree}C, 550{degree}C, and 650{degree}C to approximately 10, 20, and 40 dpa. At 550{degree}C, approximately 20 appm He/dpa was coimplanted with the 3.8 MeV Fe{sup ++} ions. The specimens were examined at a depth approximately halfway between the surface and the mean ion range in order to minimize the influence of the surface and of injected ions. At all temperatures, M{sub 23}C{sub 6}, also present in the unirradiated structure, was the only precipitate present. A nonuniform distribution of loops also formed at all temperatures. After the 450{degree}C and 650{degree}C irradiations, no voids were present. At 550{degree}C, the helium did not appear to have much effect. Very few faceted voids formed. At 20 and 40 dpa some bubbles were found but their density was very low. At 650{degree}C, a structure similar to a heavily over-tempered steel was produced by the irradiation. At 550{degree}C recovery was seen to a lesser extent. …

A new optical technique for quantitatively measuring the spectral density of passive scalar fluctuations in a turbulent flow has been developed. The technique exploits the photorefractive properties of BaTiO{sub 3} to separate the optical signal of the turbulent field from the coherent illumination background. It is a major improvement over existing techniques in that it is non-intrusive, has excellent frequency response and spatial resolution, and is capable of simultaneously measuring two components of the three-dimensional spectral density, {Phi}{theta}({kappa}). The technique is thus especially well suited to the directly study of anisotropic flows. We have applied this technique to study the spectrum of temperature fluctuations in a fully developed turbulent channel flow with heat addition. The flow is highly anisotropic, yet the spectrum in directions transverse to the flow is seen to exhibit an inertial--convective subrange behavior which is characteristic of isotropic flows. The spectral behavior in the flow direction, due to the direct influence of the mean strain rate, is observed to be markedly different. 17 refs., 7 figs.

Metallic coatings can be fabricated using the intense plasma generated by the metal vapor vacuum arc. We have made and tested an embodiment of vacuum arc plasma source that operates in a pulsed mode, thereby acquiring precise control over the plasma flux and so also over the deposition rate, and that is in the form of a miniature plasma gun, thereby allowing deposition of metallic thin films to be carried out in confined spaces and also allowing a number of such guns to be clustered together. The plasma is created at the cathode spots on the metallic cathode surface, and is highly ionized and of directed energy a few tens of electron volts. Adhesion of the film to the substrate is thus good. Virtually all of the solid metals of the Periodic Table can be used, including highly refractory metals like tantalum and tungsten. Films, including multilayer thin films, can be fabricated of thickness from Angstroms to microns. We have carried out preliminary experiments using several different versions of miniature, pulsed, metal vapor vacuum arc plasma guns to fabricate metallic thin films and multilayers. Here we describe the plasma guns and their operation in this application, and present examples of …

High speed data transmission using fiber optics in the data acquisition system of the Superconducting Super Collider has been investigated. Emphasis is placed on the high speed data transmission system overview, the local data network and on subassemblies, such as optical transmitters and receivers. Also, the performance of candidate subassemblies having a low power dissipation for the data acquisition system is discussed. 14 refs., 5 figs.

The rotary magnetic heat pump has attractive thermodynamic performance but it is strongly influenced by the effectiveness of the regenerator. This study uses local entropy generation analysis to evaluate the regenerator design and to suggest design improvements. The results show that performance of the proposed design is dominated by heat transfer related entropy generation. This suggests that enhancement concepts that improve heat transfer should be considered, even if the enhancement causes a significant increase in viscous losses (pressure drop). One enhancement technique, the use of flow disrupters, was evaluated and the results showed that flow disrupters can significantly reduce thermodynamic losses.

The crystal structure of vanadyl pyrophosphate has been redetermined using single crystals obtained from a near solidified melt of a microcrystalline catalyst sample. Crystals that index as vanadyl pyrophosphate obtained from this melt are variable in color. Crystallographic refinement of the single crystal x-ray diffraction data indicates that structural differences among these materials can be described in terms of crystal defects associated with linear disorder of the vanadium atoms. The importance of the disorder is outlined in the context of its effect on the proposed surface topology parallel to (1,0,0). Models of the surface topology simply and intuitively account for the non-stoichometric surface atomic P/V ratio exhibited by selective catalysts of this phase. These models also point to the possible role of the excess phosphorus in providing site isolation of reactive centers at the surface. 33 refs., 7 figs.

A small low energy cyclotron (the cyclotrino''), which was proposed for direct detection of radiocarbon in 1980, has now detected radiocarbon at natural abundance. This device combines the suppression of background through the use of negative ions with the high intrinsic mass resolution of a cyclotron. A high current cesium sputter negative ion source generates a beam of carbon ions which is pre-separated with Wien filter and is transported to the cyclotron via a series of electrostatic lenses. Beam is injected radially into the cyclotron using electrostatic deflectors and an electrostatic mirror. Axial focusing is entirely electrostatic. A microchannel plate detector is used with a phase-gated output. Data is presented showing resolution of radiocarbon at natural abundance. In its present form the system is capable of improving the sensitivity of detecting {sup 14}C in some biomedical experiments by a factor of 10{sup 4}. Modifications are discussed which could bring about an additional factor of 100 in sensitivity, which is important for archaeological and geological applications. Possibilities for measurements of other isotopes are discussed. 16 refs., 7 figs.

The Department of Energy sponsored Atomspheric Studies in Complex Terrain (ASCOT) program has conducted a research program designed to increase our knowledge and understanding of terrain-dominated flows with specific emphasis on nocturnal flows within mountain valleys. ASCOT has sponsored both field studies and numerical modeling efforts to improve our understanding of the wind, temperature and turbulence structure of nocturnal drainage flows. One of the most recent ASCOT sponsored field studies involves a study within the Mesa Creek Basin in western Colorado to investigate the seasonal frequency of occurrence of drainage flows along the sloped surfaces and within the basin, and to evaluate the effect of the ambient meteorology on their development. The Mesa Creek Basin, situated on the north slope of the Grand Mesa, encompasses a roughly 10 {times} 20 km area that is approximately 30 km east of Grand Junction. The observational segment of the study was undertaken jointly by the Lawrence Livermore National Laboratory and the NOAA Wave Propagation Laboratory, and involved the operation of network of eight meteorological towers and a monostatic sodar within the Mesa Creek study area over a period of one year that extended from December 1988 through November 1989. These measurements were augmented …

We report on the electrostatic design and related measurements of the barrel Cherenkov Ring Imaging Detector for the Stanford Large Detector experiment at the Stanford Linear Accelerator Center Linear Collider. We include test results of photon feedback in TMAE-laden gas, distortion measurements in the drift boxes and corona measurements. 13 refs., 21 figs.

Magnetohydrodynamic (MHD) activity within three zones (core, half- radius, and edge) of TFTR (Plasma Physics and Controlled Nuclear Fusion Research (1986), (IAEA, Vienna, 1987), Vol. 1, P. 51) tokamak plasmas are discussed. Near the core of the plasma column, sawteeth are often observed. Two types of sawteeth are studied in detail: one with complete, and the other with incomplete magnetic reconnection. Their characteristics are determined by the shape of the q profile. Near the half-radius the m/n = 3/2 and 2/1 resistive ballooning modes are found to correlate with a beta collapse. The pressure and the pressure gradient at the mode rational surface are found to play an important role in stability. MHD activity is also studied at the plasma edge during limiter H-modes. The Edge Localized Mode (ELMs) are found to have a precursor mode with a frequency between 50--200 kHz and a mode number m/n = 1/0. The mode does not show a ballooning structure. While these instabilities have been studied on many other machines, on TFTR the studies have been extended to high pressure (plasma pressure greater than 4 {times} 10{sup 5} Pa) and low collisionality. 16 refs., 3 figs.

The System Engineering Cost Analysis (SECA) capability has been developed by the System Integration Branch of the US Department of Energy's Office of Civilian Radioactive Waste Management for use in assessing the cost performance of alternative waste management system configurations. The SECA capability is designed to provide rapid cost estimates of the waste management system for a given operational scenario and to permit aggregate or detailed cost comparisons for alternative waste system configurations. This capability may be used as an integral part of the System Integration Modeling System (SIMS) or, with appropriate input defining a scenario, as a separate cost analysis model.

The International Workshop on Hadron Facility Technology was held February 20--25, 1989, at the Study Center at Los Alamos National Laboratory. This volume (second of two) included papers on computer controls, polarized beam, rf, magnet and power supplies, experimental areas, and instabilities. Participants included groups from AHF, Brookhaven National Laboratory, European Hadron Facility, Fermilab, and the Moscow Meson Factory. The workshop was well attended by members of the Los Alamos staff. The interchange of information and the opportunity by criticism by peers was important to all who attended.

As part of AGS Experiment 802, an array of 245 Lead Glass blocks, covering half the azimuth, with a polar angular acceptance approximately 8{degree} {le} {theta} {le} 32{degree}, which corresponds roughly to a laboratory pseudo rapidity range 1.25 {le} {eta} {le} 2.50 with good acceptance, when edges and corners are taken into account, measured the transverse energy (E{sub T}) distributions from primary beams of protons, {sup 16}O, and {sup 28}Si, at 14.6 A Gev/c, incident on targets of Be, Al, Cu and Au. The lead glass is most sensitive to electromagnetic radiation, but also responds to charged hadrons. The total detector response provides a good measure of the global pion yield in the central rapidity region of these reactions. Correlations among the 4 detector systems in E802 are shown to be a powerful diagnostic tool. Latest results of the analysis in progress, including dE{sub T}/d{eta} distributions, are presented, with emphasis on the proton -- nucleus data. Additionally, these data, and previous measurements of pseudorapidity distributions of multiplicity and Transverse Energy at both the AGS and CERN are analyzed in an acceptance-independent and model-independent method, with the conclusion that simple considerations of nuclear geometry do not provide an explanation of the …

For more than 10 years the conventional media for High Energy Physics has been 9 track magnetic tape in various densities. More recently, especially in Europe, the IBM 3480 technology has been adopted while in the United States, especially at Fermilab, 8mm is being used by the largest experiments as a primary recording media and where possible they are using 8mm for the production, analysis and distribution of data summary tapes. VHS and Digital Audio tape have recurrently appeared but seem to serve primarily as back-up storage media. The reasons for what appear to be a radical departure are many. Economics, form factor, and convenience are dominant among the reasons. The traditional data media suppliers seem to have been content to evolve the traditional media at their own pace with only modest enhancements primarily in value engineering'' of extant products. Meanwhile, start-up companies providing small system and workstations sought other media both to reduce the price of their offerings and respond to the real need of lower cost back-up for lower cost systems. This happening in a market context where traditional computer systems vendors were leaving the tape market altogether or shifting to 3480'' technology which has certainly created a …

Experimental transition energies in the superdeformed (SD) bands near A = 190 are least-squares fit to rotational model formulae in order to extract level spin. The data set includes 16 SD bands, which show no evidence of either irregular behavior near the bottom of the bands or abrupt angular momentum alignment at low {Dirac h}{omega}. The 9 transitions lowest in energy in each band are well described by the formulae. The fitted spin of the final state in the {gamma}-ray cascade is within {plus minus}0.1{Dirac h} of an integer or half-odd integer for 13 of the bands. The weight of the evidence suggests that meaningful level spins corresponding to these transitions can be inferred. The moment of inertia at {omega} = 0 is correlated, with I = 88.3(5){Dirac h}{sup 2}/MeV and I = 93.4(5){Dirac h}{sup 2}/MeV for the strong and weak bands, respectively. 19 refs., 2 figs., 2 tabs.

The 2 billion square meters (m{sup 2}) of building windows in the United States cause a national energy drain almost as large as the energy supply of the Alaskan oil pipeline. Unlike the pipeline, the drain of energy through windows will continue well into the 21st century. A part of this energy drain is due to unwanted sun gain through windows. This is a problem throughout the country in commercial buildings because they generally require air conditioning even in cold climates. New commercial windows create an additional 1600 MW demand for peak electric power in the United States each year. Sun control films, widely used in new windows and as retrofits to old windows, help to mitigate this problem. However, conventional, static solar control films also block sunlight when it is wanted for warmth and daylighting. New electrochromic, switchable, sun-gain-control films now under development will provide more nearly optimal and automatic sun control for added comfort, decreased building operating expense, and greater energy saving. Switchable, electrochromic films can be deposited on polymers at high speeds by plasma enhanced chemical vapor deposition (PECVD) in a process that may be suitable for roll coating. This paper describes the electrochromic coatings and the …

Excited hadronic matter in the temperature interval T = 100--200 MeV is not an ideal pion gas, but rather a liquid, in which attractive interaction among particles plays an important role. Pion dispersion curve is in this case essentially modified by a kind of collective momentum-dependent potential, which becomes important as the quasipion'' comes to the boundary of the system. We show that effects can provide and explanation for a number of recent experimental puzzles, in particular, for the observed copious production of soft pions and soft photons in high energy hadronic reactions. 31 refs., 13 figs.

In all active liquid-dominated geothermal systems there is continuous circulation of mass and transfer of heat, otherwise they would slowly cool and fade away. In the natural state these systems are in dynamic equilibrium with the surrounding colder groundwater aquifers. The ascending geothermal fluids cool conductively, boil, or mix with groundwaters, and ultimately may discharge at the surface as fumaroles or hot springs. With the start of fluid production and the lowering of reservoir pressure, the natural equilibrium is disrupted and cooler groundwater tends to enter the reservoir. Improperly constructed or damaged wells, and wells located near the margins of the geothermal system, exhibit temperature reductions (and possibly scaling from mixing of chemically distinct fluids) as the cooler-water moves into the reservoir. These negative effects, especially in peripheral wells are, however, compensated by the maintenance of reservoir pressure and a reduction in reservoir boiling that might result in mineral precipitation in the formation pores and fractures. The positive effect of cold groundwater entry on the behavior of liquid-dominated system is illustrated by using simple reservoir models. The simulation results show that even though groundwater influx into the reservoir causes cooling of fluids produced from wells located near the cold-water recharge …

The revival of interest in nuclear ground-state octupole deformations that occurred in the 1980's was stimulated by observations in 1980 of particularly large deviations between calculated and experimental masses in the Ra region, in a global calculation of nuclear ground-state masses. By minimizing the total potential energy with respect to octupole shape degrees of freedom in addition to {epsilon}{sub 2} and {epsilon}{sub 4} used originally, a vastly improved agreement between calculated and experimental masses was obtained. To study the global behavior and interrelationships between other nuclear properties, we calculate nuclear ground-state masses, spins, pairing gaps and {Beta}-decay and half-lives and compare the results to experimental qualities. The calculations are based on the macroscopic-microscopic approach, with the microscopic contributions calculated in a folded-Yukawa single-particle potential.