188 Matching Results

Search Results

Results: 1 - 24 next
open access

Large scale copper vapor laser computer control system

Description: High power pulse copper vapor laser systems consist of a master oscillator and numerous power amplifiers. Large systems used in laser isotope separation experiments require several automatic control systems. The rapid development of compact mini computers over the past several years has enabled the implementation of sophisticated computer controlled copper vapor laser systems. Present systems provide automatic time synchronization and input power stabilization. Future systems will incorporate s… more
Date: May 15, 1979
Creator: LaChapell, M. J.; Spencer, L. W. & Coutts, G. W.
Partner: UNT Libraries Government Documents Department
open access

High-resolution simulations and modeling of reshocked single-mode Richtmyer-Meshkov instability. I. Comparison to experimental data and to amplitude growth model predictions

Description: The reshocked single-mode Richtmyer-Meshkov instability is simulated in two spatial dimensions using the fifth- and ninth-order weighted essentially non-oscillatory shock-capturing method with uniform spatial resolution of 256 points per initial perturbation wavelength. The initial conditions and computational domain are modeled after the single-mode, Mach 1.21 air(acetone)/SF{sub 6} shock tube experiment of Collins and Jacobs [J. Fluid Mech. 464, 113 (2002)]. The simulation densities are shown… more
Date: May 15, 2006
Creator: Latini, M; Schilling, O & Don, W
Partner: UNT Libraries Government Documents Department
open access

Comparison of LiMnPO4 made by Combustion and Hydrothermal Syntheses

Description: Among the olivine-structured metal phosphate family, LiMnPO{sub 4} exhibits a high discharge potential (4V), which is still compatible with common electrolytes, making it interesting for use in the next generation of Li ion batteries. The extremely low electronic conductivity of this material severely limits its electrochemical performance, however. One strategy to overcome this limitation is to make LiMnPO{sub 4} nanoparticulate to decrease the diffusion distance. Another is to add a carbon or… more
Date: May 15, 2008
Creator: Chen, Jiajun; Doeff, Marca M. & Wang, Ruigang
Partner: UNT Libraries Government Documents Department
open access

Analysis of Injection-Induced Micro-Earthquakes in a Geothermal Steam Reservoir, The Geysers Geothermal Field, California

Description: In this study we analyze relative contributions to the cause and mechanism of injection-induced micro-earthquakes (MEQs) at The Geysers geothermal field, California. We estimated the potential for inducing seismicity by coupled thermal-hydrological-mechanical analysis of the geothermal steam production and cold water injection to calculate changes in stress (in time and space) and investigated if those changes could induce a rock mechanical failure and associated MEQs. An important aspect of th… more
Date: May 15, 2008
Creator: Rutqvist, Jonny; Rutqvist, J. & Oldenburg, C.M.
Partner: UNT Libraries Government Documents Department
open access

Promising X-ray fluorescence tests for superconducting tunneljunction detector

Description: Scientists in the Physical Biosciences Division of the Ernest Orlando Berkeley National Laboratory (Berkeley Lab) studying transition metals in proteins with fluorescence-detected L-edge absorption spectroscopy have found the measurements to be extremely challenging. The difficulty is that the metal centers are present in very dilute concentrations so that their weak fluorescence is often obscured by strong background signals carbon and oxygen. To solve this problem, the Berkeley group has been… more
Date: May 15, 2001
Creator: Friedrich, Stephan & Robinson, Arthur L.
Partner: UNT Libraries Government Documents Department
open access

Optimal Knot Selection for Least-squares Fitting of Noisy Data with Spline Functions

Description: An automatic data-smoothing algorithm for data from digital oscilloscopes is described. The algorithm adjusts the bandwidth of the filtering as a function of time to provide minimum mean squared error at each time. It produces an estimate of the root-mean-square error as a function of time and does so without any statistical assumptions about the unknown signal. The algorithm is based on least-squares fitting to the data of cubic spline functions.
Date: May 15, 2008
Creator: Blair, Jerome
Partner: UNT Libraries Government Documents Department
open access

Target Plate Conditions During Stochastic Boundary Operation on DIII-D

Description: A major concern for large tokamaks like ITER is the presence of edge localized modes (ELMs) that repeatedly send large bursts of particles and heat into the divertor plates. Operation with resonant magnetic perturbations (RMP) at the boundary of DIII=D has suppressed ELMs for values of q95 {approx} 3.7. At the target plate, the conditions during ELM suppressed operation for both high and low collisionality are observed by a set of radially distributed Langmuir probes. At high collisionality (n*… more
Date: May 15, 2006
Creator: Watkins, J; Evans, T; Moyer, R; Lasnier, C & Rudakov, D
Partner: UNT Libraries Government Documents Department
open access

Experimental and Numerical Studies of Separatrix Splitting and Magnetic Footprints in DIII-D

Description: A numerical field line integration code is used to study the structure of divertor footprints produced by small non-axisymmetric magnetic perturbation in the DIII-D tokamak. The numerical modeling results are compared to experimental infrared camera data which show a splitting of the divertor target plate heat flux into several distinct peaks when an n=3 magnetic perturbation from the DIII-D I-coil is applied. The heat flux splitting consistently appears when the n=3 perturbation is applied and… more
Date: May 15, 2006
Creator: Evans, T; Joseph, I; Moyer, R; Fenstermacher, M; Lasnier, C & Yan, L
Partner: UNT Libraries Government Documents Department
open access

Japan's Residential Energy Demand Outlook to 2030 Considering Energy Efficiency Standards"Top-Runner Approach"

Description: As one of the measures to achieve the reduction in greenhouse gas emissions agreed to in the"Kyoto Protocol," an institutional scheme for determining energy efficiency standards for energy-consuming appliances, called the"Top-Runner Approach," was developed by the Japanese government. Its goal is to strengthen the legal underpinnings of various energy conservation measures. Particularly in Japan's residential sector, where energy demand has grown vigorously so far, this … more
Date: May 15, 2008
Creator: Lacommare, Kristina S H; Komiyama, Ryoichi & Marnay, Chris
Partner: UNT Libraries Government Documents Department
open access

Specific interactions between arbuscular mycorrhizal fungi and plant growth-promoting bacteria--as revealed by different combinations

Description: The interactions between two plant growth promoting rhizobacteria (PGPR), Pseudomonas fluorescens SBW25 and Paenibacillus brasilensis PB177, two arbuscular mycorrhizal (AM) fungi (Glomus mosseae and G. intraradices) and one pathogenic fungus (Microdochium nivale) were investigated on winter wheat (Triticum aestivum cultivar Tarso) in a greenhouse trial. PB177, but not SBW25, had strong inhibitory effects on M. nivale in dual culture plate assays. The results from the greenhouse experiment show … more
Date: May 15, 2008
Creator: Jaderlund, Lotta; Arthurson, Veronica; Granhall, Ulf & Jansson, Janet K.
Partner: UNT Libraries Government Documents Department
open access

A comparison between Gauss-Newton and Markov chain Monte Carlo basedmethods for inverting spectral induced polarization data for Cole-Coleparameters

Description: We develop a Bayesian model to invert spectral induced polarization (SIP) data for Cole-Cole parameters using Markov chain Monte Carlo (MCMC) sampling methods. We compare the performance of the MCMC based stochastic method with an iterative Gauss-Newton based deterministic method for Cole-Cole parameter estimation through inversion of synthetic and laboratory SIP data. The Gauss-Newton based method can provide an optimal solution for given objective functions under constraints, but the obtained… more
Date: May 15, 2008
Creator: Chen, Jinsong; Kemna, Andreas & Hubbard, Susan S.
Partner: UNT Libraries Government Documents Department
open access

AN ENHANCED HAZARD ANALYSIS PROCESS FOR THE HANFORD TANK FARMS

Description: CH2M HILL Hanford Group, Inc., has expanded the scope and increased the formality of process hazards analyses performed on new or modified Tank Farm facilities, designs, and processes. The CH2M HILL process hazard analysis emphasis has been altered to reflect its use as a fundamental part of the engineering and change control process instead of simply being a nuclear safety analysis tool. The scope has been expanded to include identification of accidents/events that impact the environment, or r… more
Date: May 15, 2008
Creator: MV, SHULTZ
Partner: UNT Libraries Government Documents Department
open access

High-voltage-compatible, fully depleted CCDs

Description: We describe charge-coupled device (CCD) developmentactivities at the Lawrence Berkeley National Laboratory (LBNL).Back-illuminated CCDs fabricated on 200-300 mu m thick, fully depleted,high-resistivity silicon substrates are produced in partnership with acommercial CCD foundry.The CCDs are fully depleted by the application ofa substrate bias voltage. Spatial resolution considerations requireoperation of thick, fully depleted CCDs at high substrate bias voltages.We have developed CCDs that are c… more
Date: May 15, 2006
Creator: Holland, Stephen E.; Bebek, Chris J.; Dawson, Kyle S.; Emes, JohnE.; Fabricius, Max H.; Fairfield, Jessaym A. et al.
Partner: UNT Libraries Government Documents Department
open access

Analysis of pumping-induced unsaturated regions beneath aperennial river

Description: The presence of an unsaturated region beneath a streambedduring groundwater pumping near streams reduces the pumping capacity whenit reaches the well screens, changes flow paths, and alters the types ofbiological transformations in the streambed sediments. Athree-dimensional, multi-phase flow model of two horizontal collectorwells along the Russian River near Forestville, California was developedto investigate the impact of varying the ratio of the aquifer tostreambed permeability on (1) the fo… more
Date: May 15, 2007
Creator: Su, G.W.; Jasperse, J.; Seymour, D.; Constantz, J. & Zhou, Q.
Partner: UNT Libraries Government Documents Department
open access

Distributed Energy Resources On-Site Optimization for Commercial Buildings with Electric and Thermal Storage Technologies

Description: The addition of storage technologies such as flow batteries, conventional batteries, and heat storage can improve the economic as well as environmental attractiveness of on-site generation (e.g., PV, fuel cells, reciprocating engines or microturbines operating with or without CHP) and contribute to enhanced demand response. In order to examine the impact of storage technologies on demand response and carbon emissions, a microgrid's distributed energy resources (DER) adoption problem is formulat… more
Date: May 15, 2008
Creator: Lacommare, Kristina S H; Stadler, Michael; Aki, Hirohisa; Firestone, Ryan; Lai, Judy; Marnay, Chris et al.
Partner: UNT Libraries Government Documents Department
open access

APPLICATION OF POLYURETHANE FOAM FOR IMPACT ABSORPTION AND THERMAL INSULATION FOR RADIOACTIVE MATERIALS PACKAGINGS.

Description: Polyurethane foam has been widely used as an impact absorbing and thermal insulating material for large radioactive materials packages, since the 1980's. With the adoption of the regulatory crush test requirement, for smaller packages, polyurethane foam has been adopted as a replacement for cane fiberboard, because of its ability to withstand the crush test. Polyurethane foam is an engineered material whose composition is much more closely controlled than that of cane fiberboard. In addition, t… more
Date: May 15, 2007
Creator: Smith, A; Glenn Abramczyk, G; Paul Blanton, P; Steve Bellamy, S; William Daugherty, W & Sharon Williamson, S
Partner: UNT Libraries Government Documents Department
open access

Estimation of composite thermal conductivity of a heterogeneousmethane hydrate sample using iTOUGH2

Description: We determined the composite thermal conductivity (ktheta) ofa porous methanehydrate sample (composedof hydrate, water, and methan egas) as a function of density using iTOUGH2. X-ray computed tomography(CT) was used to visualize and quantify the density changes that occurredduring hydrate formation from granular ice. The composite thermalconductivity was estimated and validated by minimizing the differencesbetween the observed and the predicted thermal response using historymatching. The estimat… more
Date: May 15, 2006
Creator: Gupta, Arvind; Kneafsey, Timothy J.; Moridis, George J.; Seol,Yongkoo; Kowalsky, Michael B. & Sloan Jr., E.D.
Partner: UNT Libraries Government Documents Department
open access

Mesoscale Characterization of Coupled Hydromechanical Behavior of a Fractured Porous Slope in Response to Free Water-Surface Movement

Description: To better understand the role of groundwater-level changes on rock-slope deformation and damage, a carbonate rock slope (30 m x 30 m x 15 m) was extensively instrumented for mesoscale hydraulic and mechanical measurements during water-level changes. The slope is naturally drained by a spring that can be artificially closed or opened by a water gate. In this study, a 2-hour slope-dewatering experiment was analyzed. Changes in fluid pressure and deformation were simultaneously monitored, both at … more
Date: May 15, 2008
Creator: Rutqvist, Jonny; Guglielmi, Y.; Cappa, F.; Rutqvist, J.; Tsang, C.-F. & Thoraval, A.
Partner: UNT Libraries Government Documents Department
open access

Examination of the platinum effect on the oxidation behavior ofnickel-aluminide coatings

Description: Oxidation resistant nickel-aluminide coatings are designed to develop a protective alumina scale during high temperature exposure. It is well established that platinum additions, typically about 6-8 at%, provide substantial improvements in oxidation resistance of such coatings, yet the nature of the platinum effect is still not fully understood. In this work, the oxidation behavior of two commercial NiAl and NiPtAl coatings deposited on the same Ni-base single crystal alloy CMSX-4 was analyzed.… more
Date: May 15, 2007
Creator: Hou, Peggy Y. & Tolpygo, V. K.
Partner: UNT Libraries Government Documents Department
open access

A sensor array system for monitoring moisture dynamics inunsaturated soil

Description: To facilitate investigations of moisture dynamics inunsaturated soil, we have developed a technique to qualitatively monitorpatterns of saturation changes. Field results suggest that this device,the sensor array system (SAS), is suitable for determining changes inrelative wetness along vertical soil profiles. The performance of theseprobes was compared with that of the time domain reflectometry (TDR)technique under controlled and field conditions. Measurements from bothtechniques suggest that b… more
Date: May 15, 2007
Creator: Salve, R. & Cook, P.J.
Partner: UNT Libraries Government Documents Department
open access

Effects of organic carbon supply rates on mobility of previously bioreduced uranium in a contaminated sediment

Description: Bioreduction-based strategies for remediating uranium (U)-contaminated sediments face the challenge of maintaining the reduced status of U for long times. Because groundwater influxes continuously bring in oxidizing terminal electron acceptors (O{sub 2}, NO{sub 3}{sup -}), it is necessary to continue supplying organic carbon (OC) to maintain the reducing environment after U bioreduction is achieved. We tested the influence of OC supply rates on mobility of previously microbial reduced uranium U… more
Date: May 15, 2008
Creator: Wan, J.; Tokunaga, T.K.; Kim, Y.; Brodie, E.; Daly, R.; Hazen, T.C. et al.
Partner: UNT Libraries Government Documents Department
open access

Spectroscopic Characterization and Simulation of Chemical Sputtering Using the DiMES Porous Plug Injector in DIII-D

Description: A self-contained gas injection system for the Divertor Material Evaluation System (DiMES) on DIII-D has been employed for in-situ study of chemical erosion in the tokamak divertor environment. The Porous Plug Injector (PPI) releases methane, a major component of molecular influx due to chemical sputtering of graphite, from the tile surface into the plasma at a controlled rate through a porous graphite surface. Perturbation to local plasma is minimized, while also simulating the immediate enviro… more
Date: May 15, 2006
Creator: McLean, A. G.; Davis, J. W.; Stangeby, P. C.; Brooks, N. H.; Whyte, D. G.; Allen, S. L. et al.
Partner: UNT Libraries Government Documents Department
open access

Well blowout rates and consequences in California Oil and Gas District 4 from 1991 to 2005: Implications for geological storage of carbon dioxide

Description: Well blowout rates in oil fields undergoing thermally enhanced recovery (via steam injection) in California Oil and Gas District 4 from 1991 to 2005 were on the order of 1 per 1,000 well construction operations, 1 per 10,000 active wells per year, and 1 per 100,000 shut-in/idle and plugged/abandoned wells per year. This allows some initial inferences about leakage of CO2 via wells, which is considered perhaps the greatest leakage risk for geological storage of CO2. During the study period, 9% o… more
Date: May 15, 2008
Creator: Jordan, Preston; Jordan, Preston D. & Benson, Sally M.
Partner: UNT Libraries Government Documents Department
Back to Top of Screen