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Bunch cleaning strategies and experiments at the Advanced Photon Source.

Description: The Advanced Photon Source (APS) design incorporated a positron accumulator ring (PAR) as part of the injector chain. In order to increase reliability and accommodate other uses of the injector, APS will run with electrons, eliminating the need for the PAR, provided another method of eliminating rf bucket pollution in the APS is found. Satellite bunches captured from an up to 30-ns-long beam from the linac need to be removed in the injector synchrotron and storage ring. The bunch cleaning method considered here relies on driving a stripline kicker with an amplitude modulated (AM) carrier signal where the carrier is at a revolution harmonic sideband corresponding to the vertical tune. The envelope waveform is phased so that all bunches except a single target bunch (eventually to be injected into the storage ring) are resonated vertically into a scraper. The kicker is designed with a large enough shunt impedance to remove satellite bunches from the injection energy of 0.4 GeV up to 1 GeV. Satellite bunch removal in the storage ring relies on the single bunch current tune shift resulting from the machine impedance. Small bunches remaining after initial preparation in the synchrotron may be removed by driving the beam vertically into a scraper using a stripline kicker operating at a sideband corresponding to the vertical tune for small current bunches. In this paper both design specifications and bunch purity measurements are reported for both the injector synchrotron and storage ring.
Date: April 15, 1999
Creator: Sereno, N. S.
Partner: UNT Libraries Government Documents Department

Low-(18)O Silicic Magmas: Why Are They So Rare?

Description: LOW-180 silicic magmas are reported from only a small number of localities (e.g., Yellowstone and Iceland), yet petrologic evidence points to upper crustal assimilation coupled with fractional crystallization (AFC) during magma genesis for nearly all silicic magmas. The rarity of 10W-l `O magmas in intracontinental caldera settings is remarkable given the evidence of intense 10W-l*O meteoric hydrothermal alteration in the subvolcanic remnants of larger caldera systems. In the Platoro caldera complex, regional ignimbrites (150-1000 km3) have plagioclase 6180 values of 6.8 + 0.1%., whereas the Middle Tuff, a small-volume (est. 50-100 km3) post-caldera collapse pyroclastic sequence, has plagioclase 8]80 values between 5.5 and 6.8%o. On average, the plagioclase phenocrysts from the Middle Tuff are depleted by only 0.3%0 relative to those in the regional tuffs. At Yellowstone, small-volume post-caldera collapse intracaldera rhyolites are up to 5.5%o depleted relative to the regional ignimbrites. Two important differences between the Middle Tuff and the Yellowstone 10W-180 rhyolites elucidate the problem. Middle Tuff magmas reached water saturation and erupted explosively, whereas most of the 10W-l 80 Yellowstone rhyolites erupted effusively as domes or flows, and are nearly devoid of hydrous phenocrysts. Comparing the two eruptive types indicates that assimilation of 10W-180 material, combined with fractional crystallization, drives silicic melts to water oversaturation. Water saturated magmas either erupt explosively or quench as subsurface porphyrins bejiire the magmatic 180 can be dramatically lowered. Partial melting of low- 180 subvolcanic rocks by near-anhydrous magmas at Yellowstone produced small- volume, 10W-180 magmas directly, thereby circumventing the water saturation barrier encountered through normal AFC processes.
Date: October 15, 1998
Creator: Balsley, S.D. & Gregory, R.T.
Partner: UNT Libraries Government Documents Department

Increased Mercury Bioaccumulation Follows Water Quality Improvement

Description: Changes in physical and chemical characteristics of aquatic habitats made to reduce or eliminate ecological risks can sometimes have unforeseen consequences. Environmental management activities on the U.S. Dept. of Energy reservation in Oak Ridge, Tennessee,have succeeded in improving water quality in streams impacted by discharges fi-om industrial facilities and waste disposal sites. The diversity and abundance of pollution-sensitive components of the benthic macroinvertebrate communities of three streams improved after new waste treatment systems or remedial actions reduced inputs of various toxic chemicals. Two of the streams were known to be mercury-contaminated from historical spills and waste disposal practices. Waterborne mercury concentrations in the third were typical of uncontaminated systems. In each case, concentrations of mercury in fish, or the apparent biological availability of mercury increased over the period during which ecological metrics indicated improved water quality. In the system where waterborne mercury concentrations were at background levels, increased mercury bioaccumulation was probably a result of reduced aqueous selenium concentrations; however, the mechanisms for increased mercury accumulation in the other two streams remain under investigation. In each of the three systems, reduced inputs of metals and inorganic anions was followed by improvements in the health of aquatic invertebrate communities. However, this reduction in risk to aquatic invertebrates was accompanied by increased risk to humans and piscivorous wildlife related to increased mercury concentrations in fish.
Date: September 15, 1999
Creator: Bogle, M.A.; Peterson, M.J.; Smith, J.G. & Southworth, G.R.
Partner: UNT Libraries Government Documents Department

Magnetic imaging of interlayer Josephson vortices.

Description: The authors have magnetically imaged interlayer Josephson vortices emerging parallel to the planes of single crystals of the organic superconductor {kappa}-(BEDT-TTF){sub 2} Cu(NCS){sub 2}, and the single layer cuprate high-T{sub c} superconductors Tl{sub 2}Ba{sub 2}CuO{sub 6+{delta}} (Tl-2201) and (Hg,Cu)Ba{sub 2}CuO{sub 6+{delta}} (Hg-1201), using a scanning Superconducting Quantum Interference Device (SQUID) microscope. These images provide a direct measurement of the interlayer penetration depth, which is approximately 63 {micro}m for {kappa}-(BEDT-TTF){sub 2} Cu(NCS){sub 2}, 18 {micro}m for Tl-2201 and 8 {micro}m for Hg-1201. The lengths for the cuprates are about a factor of 10 larger than originally predicted by the interlayer tunneling model for the mechanism of superconductivity in layered compounds, indicating that this mechanism alone cannot account for the high critical temperatures in these materials.
Date: January 15, 1999
Creator: Kirtley, J. A.
Partner: UNT Libraries Government Documents Department

A procedure for the automatic estimation of mixed layer height.

Description: The daytime mixed layer results from mechanical and thermal turbulence processes driven by differences in air-surface temperature and moisture. As such, the height of the mixed layer (z{sub i}) is a measure of the effectiveness of energy transfer from the sun to the earth's surface and, in turn, to the lower atmosphere (Stun, 1989). Maximum daytime values for z{sub i} in the region of the Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) vary from less than 100 m in cloudy, moist, calm, stable conditions to nearly 3 km in clear, dry, unstable conditions. The principal characteristic of the mixed layer is that scalar quantities such as moisture and temperature are mixed throughout. Thus, z{sub i} becomes one of the principal scaling parameters used to describe the structure of the lower planetary boundary layer. Normally, a stable layer (a potential temperature inversion) at the top of the mixed layer interfaces between processes in the lower atmosphere and in the free atmosphere above. The strength of this inversion limits the rate of growth of z{sub i} with time and the vertical transfer of energy and moisture. When and if z{sub i} reaches the condensation level, clouds can form; hence, cloud base height (particularly for fair-weather cumulus clouds) often coincides with z{sub i} later in the day. Although the concept of the mixed layer height is straightforward, its measurement can be relatively difficult, or at least awkward. The most reliable method is an analysis of potential temperature and mixing ratio profiles retrieved from balloon ascents. (The potential temperature changes from constant to increasing with height; the mixing ratio changes from constant to decreasing with height.) Often however, the profiles of temperature and moisture are ambiguous, with multiple inversions or none at all. In addition these profiles supply only a snapshot of ...
Date: April 15, 1998
Creator: Coulter, R. L.
Partner: UNT Libraries Government Documents Department

Molten-caustic-leaching (Gravimelt) system integration project. Quarterly report, April--June 1989

Description: Operation of the Gravimelt Integrated Test Circuit for desulfurization and demineralization of coal has been completed. A 48-test process matrix was performed over 750 hours of operational time resulting in production of 3,000 pounds of treated coal suitable for further test and evaluation. Optimization testing was performed resulting in product coal containing 0.4 percent sulfur (0.6 lbs SO{sub 2}/MMBtu) and 0.15 percent ash with more than 85 percent organic sulfur removal, 95 percent SO{sub 2} reduction from ROM coal and 91 percent SO{sub 2} reduction from precleaned process feed. This report contains all of the product sulfur, ash, volatiles and heat content data obtained to date.
Date: July 15, 1989
Partner: UNT Libraries Government Documents Department

SITE-WIDE PHYSICAL INVENTORY TAKING AT IPPE.

Description: As part of the US-Russia Cooperative Program of Material Protection, Control and Accounting, staff members of the Institute of Physics and Power Engineering (IPPE) have implemented procedures for taking physical inventory of nuclear materials at many of the facilities within the IPPE site. These include both large facilities, with substantial inventories and requiring dedicated inventory equipment and computers, and small facilities, with smaller amounts of material and subject to inventory by portable equipment. The experience to date demonstrates good progress toward the goal of regular PITs for the most attractive nuclear materials at IPPE.
Date: April 15, 1999
Creator: Poplavko, V. Ya.
Partner: UNT Libraries Government Documents Department

A design for a removable floor-drain grill and trap for use in radioactive risk areas

Description: A design is proposed for a removable drainage grill and trap for floor drains in radioactive risk areas. One simple element provides free liquid run off, an air and fume barrier, and ready access for cleaning or replacement in event of contamination. Application may be made to existing and future untrapped drains.
Date: June 15, 1949
Creator: Olt, R.G.
Partner: UNT Libraries Government Documents Department

High rate PLD of diamond-like-carbon utilizing copper vapor lasers

Description: Thin film formation by pulsed laser deposition (PLD) has been routinely demonstrated at the laboratory scale for many elements and compounds. In order for processes based on PLD to progress from bench top experiments to commercialization, a number of key issues must be resolved. The principal limitations of current PLD technology are low deposition rate, inclusion of macro particles in the film that are ejected from the target, and difficulty in producing uniform coatings over large areas. Only thin films of very high value are considered economic at present deposition rates, of order 10 {micro}m-cm{sup 2}/h. Recently, a significant increase in PLD rate has been achieved in the laboratory, over 2,000 {micro} {center_dot} cm{sup 2}/h. These rates were accompanied by good surface characteristics by utilizing a copper vapor laser, operating at 100 W to 200 W average power and 4.3 kHz pulse repetition rate. The initial system demonstrations were performed by depositing high quality diamond-like-carbon (DLC) films with a remarkably low level of macro particle inclusions. The experiments and material characterizations performed on the deposited material are reviewed here.
Date: August 15, 1994
Creator: McLean, W. II; Fehring, E.; Dragon, E. & Warner, B.
Partner: UNT Libraries Government Documents Department

Nesting bird deterrents for the Federal Republic of Germany glass log storage pad

Description: A proposed storage pad wi11 be constructed in the 200 West Area for the storage of isotopic heat and radiation sources from the Federal Republic of Germany. The pad will be constructed in the southern portion of the Solid Waste Operations Complex near the existing Sodium Storage Pad (Figure 1). Following a biological review by Pacific Northwest National Laboratory (PNNL) personnel (Brandt 1996), it was determined that in order for construction to take place after March 15, 1997, actions would need to be taken to prevent migratory birds from nesting in the project area. Special attention was focused on preventing sage sparrows and loggerhead shrikes, both Hanford Site species of concern (DOE/RL 1996), from nesting in the area. This activity plan details the methods and procedures that will be used to implement these nesting deterrents.
Date: April 15, 1997
Creator: Mitchell, R.M.
Partner: UNT Libraries Government Documents Department

Quarterly Technical Progress Report - West Hackberry Tertiary Project

Description: The West Hackberry Tertiary Project is a field test of the concept that air injection can generate tertiary oil recovery through the Double Displacement Process is the gas displacement of a water invaded oil column for the purpose of recovering tertiary oil through gravity discharge. The novel aspect of this project is the use of air as the injection fluid.
Date: April 15, 1998
Creator: Yannimaras, Demetrois & Gillham, Travis
Partner: UNT Libraries Government Documents Department

Atomic Structure and Properties of Extended Defects in Silicon

Description: The Z-contrast technique represents a new approach to high-resolution electron microscopy allowing for the first time incoherent imaging of materials on the atomic scale. The key advantages of the technique, an intrinsically higher resolution limit and directly interpretable, compositionally sensitive imaging, allow a new level of insight into the atomic configurations of extended defects in silicon. This experimental technique has been combined with theoretical calculations (a combination of first principles, tight binding, and classical methods) to extend this level of insight by obtaining the energetic and electronic structure of the defects.
Date: October 15, 1998
Creator: Buczko, R.; Chisholm, M.F.; Kaplan, T.; Maiti, A.; Mostoller, M.; Pantelides, S.T. et al.
Partner: UNT Libraries Government Documents Department

Iodine-129 Dose in LLW Disposal Facility Performance Assessments

Description: Iodine-129 has the lowest Performance Assessment derived inventory limit in SRS disposal facilities. Because iodine is concentrated in the body to one organ, the thyroid, it has been thought that dilution with stable iodine would reduce the dose effects of 129I.Examination of the dose model used to establish the Dose conversion factor for 129I shows that, at the levels considered in performance assessments of low-level waste disposal facilities, the calculated 129I dose already accounts for ingestion of stable iodine. At higher than normal iodine ingestion rates, the uptake of iodine by the thyroid itself decrease, which effectively cancels out the isotopic dilution effect.
Date: October 15, 1999
Creator: Wilhite, E.L.
Partner: UNT Libraries Government Documents Department

Improved Oil Recovery in Fluvial Dominated Deltaic Reservoirs of Kansas - Near-Term

Description: The objective of this study is to study waterflood problems of the type found in Morrow sandstone. The major tasks undertaken are reservoir characterization and the development of a reservoir database; volumetric analysis to evaluate production performance; reservoir modeling; identification of operational problems; identification of unrecovered mobile oil and estimation of recovery factors; and identification of the most efficient and economical recovery process.
Date: October 15, 1997
Creator: Walton, A.; McCune, D.; Green, D.W.; Willhite, G.P.; Watney, L.; Michnick, M. et al.
Partner: UNT Libraries Government Documents Department

Directional dependency of air sampling; Research and development grant {number_sign}4

Description: A field study was performed by Idaho State University-Environmental Monitoring Laboratory (EML) to examine the directional dependency of low-volume air samplers. A typical continuous low volume air sampler contains a sample head that is mounted on the sampler housing either horizontally through one of four walls or vertically on an exterior wall `looking down or up.` In 1992, a field study was undertaken to estimate sampling error and to detect the directional effect of sampler head orientation. Approximately 1/2 mile downwind from a phosphate plant (continuous source of alpha activity), four samplers were positioned in identical orientation alongside one sampler configured with the sample head `looking down`. At least five consecutive weekly samples were collected. The alpha activity, beta activity, and the Be-7 activity collected on the particulate filter were analyzed to determine sampling error. Four sample heads were than oriented to the four different horizontal directions. Samples were collected for at least five weeks. Analysis of the alpha data can show the effect of sampler orientation to a know near source term. Analysis of the beta and Be-7 activity shows the effect of sampler orientation to a ubiquitous source term.
Date: January 15, 1994
Partner: UNT Libraries Government Documents Department

Recent results from the super EBIT

Description: The Super EBIT device at LLNL can produce and trap any highly charged ion at rest in the laboratory, including bare U{sup 92+} ions. Recently, the ionization cross sections for high-Z hydrogenlike ions have been measured for the first time, and measurements of the L-shell ionization cross sections for uranium ions are in progress. The two-electron contributions to the ground state energies of heliumlike ions have been directly measured using a novel technique, and spectra of 2s-2p transitions in highly ionized thorium and uranium have been used to test QED corrections to the energy levels of few electron high-Z ions. A new capability for the study of rare isotopes has been demonstrated. Ion cooling has been used to reduce the thermal broadening of x-ray emission lines to the point where natural line widths can be observed in some cases.
Date: September 15, 1995
Creator: Marrs, R.E.
Partner: UNT Libraries Government Documents Department

A novel condenser for EUV lithography ring-field projection optics

Description: A condenser for a ring-field extreme ultra-violet (EUV) projection lithography camera is presented. The condenser consists of a gently undulating mirror, that we refer to as a ripple plate, and which is illuminated by a collimated beam at grazing incidence. The light is incident along the ripples rather than across them, so that the incident beam is reflected onto a cone and subsequently focused on to the arc of the ring field. A quasistationary illumination is achieved, since any one field point receives light from points on the ripples, which are distributed throughout the condenser pupil. The design concept can easily be applied to illuminate projection cameras with various ring-field and numerical aperture specifications. Ray-tracing results are presented of a condenser for a 0.25 NA EUV projection camera.
Date: July 15, 1999
Creator: Chapman, H. & Nugent, K. A.
Partner: UNT Libraries Government Documents Department

Weak matrix elements in the large N{sub c} limit

Description: The matrix elements of the four quark operators needed to predict many weak interaction processes can be evaluated using the large N{sub c} limit of quantum chromodynamics. At leading order in the large N{sub c} expansion, the weak matrix elements of four quark operators factorize into independent matrix elements of two quark operators, a common approximation being used today. At the next leading order, the weak matrix elements acquire the leading scale and scheme dependence expected for these matrix elements in full QCD. They discuss methods to evaluate these matrix elements which involve matching perturbative QCD calculations at short distance to non-perturbative hadronic matrix elements at long distance.
Date: October 15, 1999
Creator: Bardeen, William A.
Partner: UNT Libraries Government Documents Department

Thermal and Fluid Flow Brazing Simulations

Description: The thermal response of fixtured parts in a batch-type brazing furnace can require numerous, time-consuming development runs before an acceptable furnace schedule or joint design is established. Powerful computational simulation tools are being developed to minimize the required number of verification experiments, improve furnace throughput, and increase product yields. Typical furnace simulations are based on thermal, fluid flow, and structural codes that incorporate the fundamental physics of the brazing process. The use of massively parallel computing to predict furnace and joint-level responses is presented. Measured and computed data are compared. Temperature values are within 1-270 of the expected peak brazing temperature for different loading conditions. Sensitivity studies reveal that the thermal response is more sensitive to the thermal boundary conditions of the heating enclosure than variability y in the materials data. Braze flow simulations predict fillet geometry and free surface joint defects. Dynamic wetting conditions, interfacial reactions, and solidification structure add a high degree of uncertainty to the flow results.
Date: December 15, 1999
Creator: Hosking, Floyd Michael; Gianolakis, Steven E.; Givler, Richard C. & Schunk, P. Randall
Partner: UNT Libraries Government Documents Department

FY99 Status Report on the HSV

Description: 'The HSV in storage in MTF has been monitored during FY99, and its overpressure has been sampled and analyzed. The HSV''s internal pressure continues to rise slowly, and the overpressure still analyzes as 100 percent 3He. The titanium tritide sample that was to be monitored annually and which had developed a leak last year has been repaired and isotherms measured. Unfortunately the sample was showing significant unexpected 3He release, so the isotherm data is corrupted by unknown levels of 3He. This release has disqualified this sample for future use, as it is now seriously divergent from the HSV material. A different sample must be selected for subsequent studies.The unexpected 3He releases of the Ti-3 sample and the possible release in other Ti samples have raised a serious issue. It should be determined why this release is occurring, so that an unexpected release of 3He during HSV unloading can be assessed as unlikely.'
Date: October 15, 1999
Creator: Shanahan, K. L.
Partner: UNT Libraries Government Documents Department

New experiments elucidating the current limiting mechanisms of Ag-sheathed (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} tapes.

Description: Multiple current limiting mechanisms exist from the nanometer to millimeter scale in Ag-sheathed (Bi,Pb)-2223 tapes. Recent studies of the zero-field critical current density (J{sub c} (0T, 77K)), the irreversibility field (H*) and the crack microstructure elucidate these properties. We show that H*(77K) can vary significantly over the range {approximately}120-260 mT, independently of J{sub c} (0T, 77K). Cracks, actual or incipient, exist on the sub to several hundred micron scale. Surface magneto optical imaging of whole tapes, correlated to subsequent ultrasonic fracture analysis of. the bare 2223 filaments extracted by dissolving away the Ag shows that even composites having J{sub c} (0T, 77K) values of 60 kA/cm{sup 2} exhibit strong signs of unhealed rolling damage. These combined studies show that today's very best 2223 tapes are still far from full optimization.
Date: January 15, 1999
Creator: Anderson, J. W.; Babcock, S. E.; Cai, X. Y.; Dorris, S. E.; Feldmann, M.; Jiang, J. et al.
Partner: UNT Libraries Government Documents Department

Xtoys: Cellular automata on xwindows

Description: Xtoys is a collection of xwindow programs for demonstrating simulations of various statistical models. Included are xising, for the two dimensional Ising model, xpotts, for the q-state Potts model, xautomalab, for a fairly general class of totalistic cellular automata, xsand, for the Bak-Tang-Wiesenfield model of self organized criticality, and xfires, a simple forest fire simulation. The programs should compile on any machine supporting xwindows.
Date: August 15, 1995
Creator: Creutz, M.
Partner: UNT Libraries Government Documents Department

An Overview of Surface Finishes and Their Role in Printed Circuit Board Solderability and Solder Joint Performance

Description: A overview has been presented on the topic of alternative surface finishes for package I/Os and circuit board features. Aspects of processability and solder joint reliability were described for the following coatings: baseline hot-dipped, plated, and plated-and-fused 100Sn and Sn-Pb coatings; Ni/Au; Pd, Ni/Pd, and Ni/Pd/Au finishes; and the recently marketed immersion Ag coatings. The Ni/Au coatings appear to provide the all-around best option in terms of solderability protection and wire bondability. Nickel/Pal ftishes offer a slightly reduced level of performance in these areas that is most likely due to variable Pd surface conditions. It is necessmy to minimize dissolved Au or Pd contents in the solder material to prevent solder joint embrittlement. Ancillary aspects that included thickness measurement techniques; the importance of finish compatibility with conformal coatings and conductive adhesives; and the need for alternative finishes for the processing of non-Pb bearing solders were discussed.
Date: October 15, 1998
Creator: Vianco, P.T.
Partner: UNT Libraries Government Documents Department

Tank characterization report for single-shell tank 241-S-104

Description: One of the major functions of the Tank Waste Remediation System (TWRS) is to characterize wastes in support of waste management and disposal activities at the Hanford Site. Analytical data from sampling and analysis, along with other available information about a tank, are compiled and maintained in a tank characterization report (TCR). This report and its appendixes serve as the TCR for single-shell tank 241-S-104. The objectives of this report are: (1) to use characterization data in response to technical issues associated with 241-S- 104 waste; and (2) to provide a standard characterization of this waste in terms of a best-basis inventory estimate. The response to technical issues is summarized in Section 2.0, and the best-basis inventory estimate is presented in Section 3.0. Recommendations regarding safety status and additional sampling needs are provided in Section 4.0. Supporting data and information are contained in the appendixes. This report also supports the requirements of the Hanford Federal Facility Agreement and Consent Order (Ecology et al. 1996) milestone M-44-05.
Date: April 15, 1997
Creator: Jo, J.
Partner: UNT Libraries Government Documents Department