2,262 Matching Results

Search Results

Results: 1 - 24 next
open access

THz radiation as a bunch diagnostic forlaser-wakefield-accelerated electron bunches

Description: Experimental results are reported from two measurementtechniques (semiconductor switching and electro-optic sampling) thatallow temporal characterization of electron bunches produced by alaser-driven plasma-based accelerator. As femtosecond electron bunchesexit the plasma-vacuum interface, coherent transition radiation (at THzfrequencies) is emitted. Measuring the properties of this radiationallows characterization of the electron bunches. Theoretical work on theemission mechanism is represente… more
Date: February 15, 2006
Creator: van Tilborg, J.; Schroeder, C. B.; Filip, C. V.; Toth, Cs.; Geddes, C. G. R.; Fubiani, G. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

State-of-the-Art Beta Detection and Dosimetry

Description: The research funded by this NEER grant establishes the framework for a detailed understanding of the challenges in beta dosimetry, especially in the presence of a mixed radiation field. The work also stimulated the thinking of the research group which will lead to new concepts in digital signal processing to allow collection of detection signals and real-time analysis such that simultaneous beta and gamma spectroscopy can take place. The work described herein (with detail in the many publicatio… more
Date: August 15, 2008
Creator: Hamby, David M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Engineering MerR for Sequestration and MerA for Reduction of Toxic Metals and Radionuclides

Description: The objectives of this project were (1) to alter a metalloregulatory protein (MerR) so that it would bind other toxic metals or radionuclides with similar affinity so that the engineered protein itself and/or bacteria expressing it could be deployed in the environment to specifically sequester such metals and (2) to alter the mercuric reductase, MerA, to reduce radionuclides and render them less mobile. Both projects had a basic science component. In the first case, such information about MerR … more
Date: December 15, 2008
Creator: Summers, Anne O.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Characterization of Turbiditic Oil Reservoirs Based on Geophysical Models of their Formation

Description: Models are developed and solved to describe the flow of and deposition from low and high concentration turbidity currents. The shallow water equations are amended to include particle transport to describe the low concentration turbidity currents. The suspension balance model is used to describe the high concentration turbidity currents. Numerical simulations are developed to solve the highly non-linear, free boundary problems associated with these models. Simpler, algebraic scaling relationship… more
Date: January 15, 2006
Creator: Bonnecaze, Roger
Item Type: Refine your search to only Report
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
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Similarity-Guided Streamline Placement with Error Evaluation

Description: Most streamline generation algorithms either provide a particular density of streamlines across the domain or explicitly detect features, such as critical points, and follow customized rules to emphasize those features. However, the former generally includes many redundant streamlines, and the latter requires Boolean decisions on which points are features (and may thus suffer from robustness problems for real-world data). We take a new approach to adaptive streamline placement for steady vector… more
Date: August 15, 2007
Creator: Chen, Y.; Cohen, J. D. & Krolik, J. H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Increasing FTIR spectromicroscopy speed and resolution through compressive imaging

Description: At the Advanced Light Source at Lawrence Berkeley National Laboratory, we are investigating how to increase both the speed and resolution of synchrotron infrared imaging. Synchrotron infrared beamlines have diffraction-limited spot sizes and high signal to noise, however spectral images must be obtained one point at a time and the spatial resolution is limited by the effects of diffraction. One technique to assist in speeding up spectral image acquisition is described here and uses compressive … more
Date: October 15, 2007
Creator: Gallet, Julien; Riley, Michael; Hao, Zhao & Martin, Michael C
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Site Environmental Report for 2007 Volume I

Description: The Site Environmental Report is an integrated report on Berkeley Lab's environmental programs to satisfy the requirements of DOE Order 231.1A, Environment, Safety, and Health Reporting. It summarizes Berkeley Lab's environmental management performance, presents environmental monitoring results, and describes significant programs for calendar year 2007. Volume I is organized into an executive summary followed by six chapters that contain an overview of the Laboratory, a discussion of the Labora… more
Date: September 15, 2008
Creator: Lackner, Regina E.; Baskin, David; Fox, Robert; Jelinski, John; Pauer, Ron; Thorson, Patrick et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Center for Extended Magnetohydrodynamic Modeling Cooperative Agreement

Description: The Center for Extended Magnetohydrodynamic Modeling (CEMM) is developing computer simulation models for predicting the behavior of magnetically confined plasmas. Over the first phase of support from the Department of Energy’s Scientific Discovery through Advanced Computing (SciDAC) initiative, the focus has been on macroscopic dynamics that alter the confinement properties of magnetic field configurations. The ultimate objective is to provide computational capabilities to predict plasma behavi… more
Date: February 15, 2008
Creator: Sovinec, Carl R.
Item Type: Refine your search to only Report
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
Item Type: Refine your search to only Article
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.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

An Implicit "Drift-Lorentz" Particle Mover for Plasma and Beam Simulations

Description: In order to efficiently perform particle simulations in systems with widely varying magnetization, we developed a drift-Lorentz mover, which interpolates between full particle dynamics and drift kinetics in such a way as to preserve a physically correct gyroradius and particle drifts for both large and small ratios of the timestep to the cyclotron period. In order to extend applicability of the mover to systems with plasma frequency exceeding the cyclotron frequency such as one may have with fu… more
Date: July 15, 2008
Creator: Friedman, A.; Grote, D. P.; Vay, J. L. & Cohen, R. H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Citric Acid-Modified Fenton's Reaction for the Oxidation of Chlorinated Ethylenes in Soil Solution Systems

Description: Fenton's reagent, a solution of hydrogen peroxide and ferrous iron catalyst, is used for an in-situ chemical oxidation of organic contaminants. Sulfuric acid is commonly used to create an acidic condition needed for catalytic oxidation. Fenton's reaction often involves pressure buildup and precipitation of reaction products, which can cause safety hazards and diminish efficiency. We selected citric acid, a food-grade substance, as an acidifying agent to evaluate its efficiencies for organic con… more
Date: March 15, 2008
Creator: Seol, Yongkoo & Javandel, Iraj
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

2007 Plant Metabolic Engineering Gordon Conference and Graduate Research Seminar

Description: Plant Metabolic Engineering is an emerging field that integrates a diverse range of disciplines including plant genetics, genomics, biochemistry, chemistry and cell biology. The Gordon-Kenan Graduate Research Seminar (GRS) in Plant Metabolic Engineering was initiated to provide a unique opportunity for future researcher leaders to present their work in this field. It also creates an environment allowing for peer-review and critical assessment of work without the intimidation usually associated … more
Date: September 15, 2008
Creator: Grotewold, Erich
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Evaluation of production samples of the scintillators LaBr3:Ce and LaCl3:Ce

Description: We report on the evaluation of the performance of two recently developed scintillator materials, LaCl{sub 3}:Ce and LaBr{sub 3}:Ce, at the task of gamma ray spectroscopy. Their performance is compared to a standard scintillator used for gamma ray spectroscopy--a 25 mm diameter 25 mm tall cylinder of NaI:Tl. We measure the pulse height, energy resolution, and full-energy efficiency of production LaBr{sub 3}:Ce and LaCl{sub 3}:Ce scintillation crystals of different sizes and geometries for a vari… more
Date: September 15, 2005
Creator: Choong, Woon-Seng; Derenzo, Stephen E. & Moses, William W.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

CH Packaging Operations Manual

Description: Introduction - This procedure provides instructions forassembling the following CH packaging payload: Drum payload assembly Standard Waste Box (SWB) assembly Ten-Drum Overpack (TDOP)
Date: May 15, 2007
Creator: Westinghouse TRU Solutions LLC
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

PREDICTION OF CHARACTERISTIC LENGTH AND FRACTURE TOUGHNESS IN DUCTILE-BRITTLE TRANSITION

Description: Finite element method was used to analyze the three-point bend experimental data of A533B-1 pressure vessel steel obtained by Sherry, Lidbury, and Beardsmore [1] from -160 to -45 C within the ductile-brittle transition regime. As many researchers have shown, the failure stress ({sigma}{sub f}) of the material could be approximated as a constant. The characteristic length, or the critical distance (r{sub c}) from the crack tip, at which {sigma}{sub f} is reached, is shown to be temperature depen… more
Date: April 15, 2008
Creator: Lam, P
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Biosynthesis of the Cyclotide MCoTI-II using an Engineered Intein

Description: Cyclotides are an emerging family of naturally occurring circular mini-proteins ({approx}30-40 amino acids) characterized by six conserved Cys residues (forming 3 disulfide bridges) that create a topologically unique structure designated as a cyclic cysteine knot (CCK). The cysteine knot motif, which is embedded within the macrocylic backbone, is described as two disulfide bridges that form a ring that is penetrated by the third disulfide bridge. The cyclic backbone and CCK motif together confe… more
Date: August 15, 2006
Creator: Cantor, J & Camarero, J A
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Spatial resolution limits for synchrotron-based infrared spectromicroscopy

Description: Detailed spatial resolution tests were performed on beamline 1.4.4 at the Advanced Light Source synchrotron facility in Berkeley, CA. The high-brightness synchrotron source is coupled at this beamline to a Thermo-Electron Continumum XL infrared microscope. Two types of resolution tests in both the mid-IR (using a KBr beamsplitter and an MCT-A* detector) and in the near-IR (using a CaF2 beamsplitter and an InGaAS detector) were performed and compared to a simple diffraction-limited spot size mod… more
Date: October 15, 2007
Creator: Levenson, Erika; Lerch, Philippe & Martin, Michael C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Basalt weathering rates on Earth and the duration of liquid water on the plains of Gusev Crater, Mars

Description: Where Martian rocks have been exposed to liquid water, chemistry versus depth profiles could elucidate both Martian climate history and potential for life. The persistence of primary minerals in weathered profiles constrains the exposure time to liquid water: on Earth, mineral persistence times range from {approx}10 ka (olivine) to {approx}250 ka (glass) to {approx}1Ma (pyroxene) to {approx}5Ma (plagioclase). Such persistence times suggest mineral persistence minima on Mars. However, Martian so… more
Date: March 15, 2008
Creator: Steefel, Carl; Hausrath, E. M.; Navarre-Sitchler, A. K.; Sak, P. B.; Steefel, C. & Brantley, S. L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Evaluation of the 2008 Lexus LS 600H Hybrid Synergy Drive System

Description: Subsystems of the 2008 Lexus 600h hybrid electric vehicle (HEV) were studied and tested as part of an intensive benchmarking effort carried out to produce detailed information concerning the current state of nondomestic alternative vehicle technologies. Feedback provided by benchmarking efforts is particularly useful to partners of the Vehicle Technologies collaborative research program as it is essential in establishing reasonable yet challenging programmatic goals which facilitate development… more
Date: January 15, 2009
Creator: Burress, T. A.; Coomer, C. L.; Campbell, S. L.; Wereszczak, A. A.; Cunningham, J. P.; Marlino, L. D. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
Back to Top of Screen