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Event-Driven Power-Law Relaxation in Weak Turbulence

Description: This article discusses event-driven power-law relaxation in weak turbulence.
Date: January 5, 2009
Creator: Silvestri, Ludovico; Fronzoni, Leone; Grigolini, Paolo & Allegrini, Paolo
Partner: UNT College of Arts and Sciences
open access

High Resolution Simulation of Beam Dynamics in Electron Linacs for Free Electron Lasers

Description: In this paper we report on large scale multi-physics simulation of beam dynamics in electron linacs for next generation free electron lasers (FELs). We describe key features of a parallel macroparticle simulation code including three-dimensional (3D) space-charge effects, short-range structure wake fields, longitudinal coherent synchrotron radiation (CSR) wake fields, and treatment of radiofrequency (RF) accelerating cavities using maps obtained from axial field profiles. A macroparticle up-sam… more
Date: January 5, 2009
Creator: Ryne, R.D.; Venturini, M.; Zholents, A.A. & Qiang, J.
Partner: UNT Libraries Government Documents Department
open access

CHEMICAL SAFETY: ASKING THE RIGHT QUESTIONS

Description: Recent reports have shown that, despite efforts to the contrary, chemical accidents continue to occur at an unacceptable rate and there is no evidence that this rate is decreasing. Based on this observation, one can conclude that previous analyses have not accurately identified and implemented appropriate fixes to eliminate identified root causes for chemical events. Based on this, it is time to reevaluate chemical accident data with a fresh eye and determine (a) what corrective actions have al… more
Date: August 5, 2008
Creator: Simmons, F
Partner: UNT Libraries Government Documents Department
open access

Compound-Nucleus Formation Following Direct Interactions to Highly-Excited Final States

Description: When direct reactions populate highly excited, unbound configurations in the residual nucleus, the nucleus may further evolve into a compound nucleus. Alternatively, the residual system may decay by emitting particles into the continuum. Understanding the relative weights of these two processes as a function of the angular momentum and parity deposited in the nucleus is important for the surrogate-reaction technique. A particularly interesting case is compound-nucleus formation via the (d, p) r… more
Date: February 5, 2008
Creator: Dietrich, F S
Partner: UNT Libraries Government Documents Department
open access

Transition energy correlations in the three-body continuum of Borromean halo nuclei

Description: Energy correlations in transitions from the bound state to the three-body continuum of Borromean halo nuclei are considered. A core+n+n three-body cluster model which reproduces experimentally known properties of {sup 6}He and {sup 11}Li has been used to study low-lying resonances and soft modes. The analysis of the correlated responses in {sup 6}He shows that in the case of the narrow three-body 2{sub 1}{sup +} resonance the transition energy correlations are the same as in the intrinsic corre… more
Date: June 5, 2007
Creator: Danilin, B V; Vaagen, J S; Rogde, T; Ershov, S N; Thompson, I J & Zhukov, M V
Partner: UNT Libraries Government Documents Department
open access

Abstract: Contaminant Travel Times From the Nevada Test Site to Yucca Mountain: Sensitivity to Porosity

Description: Yucca Mountain (YM), Nevada, has been proposed by the U.S. Department of Energy as a geologic repository for spent nuclear fuel and high-level radioactive waste. In this study, we investigate the potential for groundwater advective pathways from underground nuclear testing areas on the Nevada Test Site (NTS) to the YM area by estimating the timeframe for advective travel and its uncertainty resulting from porosity value uncertainty for hydrogeologic units (HGUs) in the region. We perform sensit… more
Date: September 5, 2008
Creator: Pohlmann, Karl F.; Zhu, Jianting; Chapman, Jenny B.; Russell, Charles E.; Carroll, Rosemary W. H. & Shafer, David S.
Partner: UNT Libraries Government Documents Department
open access

A korarchaeal genome reveals insights into the evolution of the Archaea

Description: The candidate division Korarchaeota comprises a group of uncultivated microorganisms that, by their small subunit rRNA phylogeny, may have diverged early from the major archaeal phyla Crenarchaeota and Euryarchaeota. Here, we report the initial characterization of a member of the Korarchaeota with the proposed name,"Candidatus Korarchaeum cryptofilum," which exhibits an ultrathin filamentous morphology. To investigate possible ancestral relationships between deep-branching Korarchaeot… more
Date: June 5, 2008
Creator: Anderson, Iain J; Elkins, James G.; Podar, Mircea; Graham, David E.; Makarova, Kira S.; Wolf, Yuri et al.
Partner: UNT Libraries Government Documents Department
open access

Single-cycle nonlinear optics

Description: Nonlinear optics plays a central role in the advancement of optical science and laser-based technologies. We report on the confinement of the nonlinear interaction of light with matter to a single wave cycle and demonstrate its utility for time-resolved and strong-field science. The electric field of 3.3-femtosecond, 0.72-micron laser pulses with a controlled and measured waveform ionizes atoms near the crests of the central wave cycle, with ionization being virtually switched off outside this … more
Date: November 5, 2008
Creator: Max-Planck-Institut fur Quantenoptik
Partner: UNT Libraries Government Documents Department
open access

2007 Nuclear Data Review

Description: The results of a review and evaluation of neutron and non-neutron nuclear data published in the scientific literature are presented. The status of new chemical elements is examined. Data on revised values for the isotopic composition of the elements are reviewed and recommended values are presented. Half-lives of very long-lived nuclides are presented, including double beta decay, double electron capture, long-lived alpha decay and long-lived beta decay. Data from new measurements on the very h… more
Date: May 5, 2008
Creator: Holden, N. E.
Partner: UNT Libraries Government Documents Department
open access

The Emma Commissioning Procedure

Description: The author begins with a brief review of the goals of the EMMA experiment. He then describe two stages of EMMA commissioning. The first stage is simply to get the beam to circulate a full turn in the ring, and is done only once during the course of the experiment. The second stage will be repeated several times, at least once for each lattice configuration, and involves two parts: setting the required values for the machine parameters, and determining the tunes and time of flight as a function … more
Date: November 5, 2007
Creator: Berg, J. S.
Partner: UNT Libraries Government Documents Department
open access

Ambient Radon-222 Monitoring in Amargosa Valley, Nevada

Description: As part of a program to characterize and baseline selected environmental parameters in the region around the proposed repository at Yucca Mountain, Nevada, ambient radon-222 monitoring was conducted in the rural community of Amargosa Valley, the community closest to the proposed repository site. Passive integrating radon monitors and a continuous radon monitoring instrument were deployed adjacent to the Community Environmental Monitoring Program (CEMP) (http://www.cemp.dri.edu/index.html) stati… more
Date: June 5, 2008
Creator: Karr, L. H.; Tappen, J. J.; Shafer, D. & Gray, K. J.
Partner: UNT Libraries Government Documents Department
open access

Non-destructive Identification of Individual Leukemia Cells by Optical Trapping Raman Spectroscopy

Description: Currently, a combination of technologies is typically required to assess the malignancy of cancer cells. These methods often lack the specificity and sensitivity necessary for early, accurate diagnosis. Here we demonstrate using clinical samples the application of laser trapping Raman spectroscopy as a novel approach that provides intrinsic biochemical markers for the noninvasive detection of individual cancer cells. The Raman spectra of live, hematopoietic cells provide reliable molecular fing… more
Date: March 5, 2007
Creator: Chan, J W; Taylor, D S; Lane, S; Zwerdling, T; Tuscano, J & Huser, T
Partner: UNT Libraries Government Documents Department
open access

Overview of the National Atmospheric Release Advisory Center's urban research and development activities

Description: This presentation describes the tools and services provided by the National Atmospheric Release Advisory Center (NARAC) at Lawrence Livermore National Laboratory (LLNL) for modeling the impacts of airborne hazardous materials. NARAC provides atmospheric plume modeling tools and services for chemical, biological, radiological, and nuclear airborne hazards. NARAC can simulate downwind effects from a variety of scenarios, including fires, industrial and transportation accidents, radiation dispersa… more
Date: September 5, 2007
Creator: Lundquist, J K; Sugiyama, G A & Nasstrom, J
Partner: UNT Libraries Government Documents Department
open access

High-Resolution Spectroscopy of K-shell Praseodymium with a High-Energy Calorimeter

Description: We present a measurement of the K-shell spectrum of He-like through Be-like praseodymium ions trapped in the Livermore SuperEBIT electron beam ion trap using a bismuth absorber pixel on the XRS/EBIT microcalorimeter. This measurement is the first of its kind where the n=2 to n=1 transitions of the various charge states are spectroscopically resolved. The measured transition energies are compared with theoretical calculations from several atomic codes.
Date: June 5, 2007
Creator: Thorn, D B; Brown, G V; Clementson, J T; Chen, H; Chen, M H; Beiersdorfer, P et al.
Partner: UNT Libraries Government Documents Department
open access

HIGHLY ENRICHED URANIUM BLEND DOWN PROGRAM AT THE SAVANNAH RIVER SITE PRESENT AND FUTURE

Description: The Department of Energy (DOE) and Tennessee Valley Authority (TVA) entered into an Interagency Agreement to transfer approximately 40 metric tons of highly enriched uranium (HEU) to TVA for conversion to fuel for the Browns Ferry Nuclear Power Plant. Savannah River Site (SRS) inventories included a significant amount of this material, which resulted from processing spent fuel and surplus materials. The HEU is blended with natural uranium (NU) to low enriched uranium (LEU) with a 4.95% 235U iso… more
Date: June 5, 2008
Creator: Magoulas, V; Charles Goergen, C & Ronald Oprea, R
Partner: UNT Libraries Government Documents Department
open access

Scintillation and Luminescence Properties of Undoped and Cerium-doped LiGdCl4 and NaGdCl4

Description: We report the scintillation properties of the undoped and cerium-doped variations of LiGdCl4 and NaGdCl4. Powder samples of these materials exhibit significant scintillation under X-rays. The samples were synthesized by solid-state methods from a 1:1 molar ratio of lithium or sodium chloride and gadolinium chloride. Cerium trichloride was used as the dopant. The physical, optical, and scintillation properties of these materials were analyzed by powder X-ray diffraction, photoluminescence, X-ray… more
Date: October 5, 2008
Creator: Porter-Chapman, Yetta D.; Bourret-Courchesne, Edith D.; Bizarri, Gregory; Weber, Marvin J. & Derenzo, Stephen E.
Partner: UNT Libraries Government Documents Department
open access

A HAMILTONIAN FORMULATION FOR SPIRAL-SECTOR ACCELERATORS.

Description: I develop a formulation for Hamiltonian dynamics in an accelerator with magnets whose edges follow a spiral. I demonstrate using this Hamiltonian that a spiral FFAG can be made perfectly 'scaling'. I examine the effect of tilting an RF cavity with respect a radial line from the center of the machine, potentially with a different angle than the spiral of the magnets.
Date: November 5, 2007
Creator: Berg, J. S.
Partner: UNT Libraries Government Documents Department
open access

Mesoscale modeling of irreversible volume growth in powders of anisotropic crystals

Description: Careful thermometric analysis (TMA) on powders of micron-sized triamino-trinitrobenzene (TATB) crystallites are shown to display irreversible growth in volume when subjected to repeated cycles of heating and cooling. Such behavior is counter-intuitive to typical materials response to simulated annealing cycles in atomic-scale molecular dynamics. However, through coarse-grained simulations using a mesoscale Hamiltonian we quantitatively reproduce irreversible growth behavior in such powdered mat… more
Date: May 5, 2006
Creator: Gee, R.; Maiti, A. & Fried, L.
Partner: UNT Libraries Government Documents Department
open access

Dynamic Characterizations of an 8-frame Half-Strip High-speed X-ray Microchannel Plate Imager

Description: High-speed microchannel plate (MCP)–based imagers are critical detectors for x-ray diagnostics employed on Z-experiments at Sandia National Laboratories (SNL) to measure time-resolved x-ray spectra and to image dynamic hohlraums. A multiframe design using eight half strips in one imager permits recordings of radiation events in discrete temporal snapshots to yield a time-evolved movie. We present data using various facilities to characterize the performance of this design. These characterizatio… more
Date: September 5, 2008
Creator: Ken Moy, Ming Wu, Craig Kruschwitz, Aric Tibbits, Matt Griffin, Greg Rochau
Partner: UNT Libraries Government Documents Department
open access

Neutral Kaon Interferometry in Au+Au collisions at sqrt(s_NN) =200 GeV

Description: We present the first statistically meaningful results fromtwo-K0s interferometry in heavy-ion collisions. A model that takes theeffect of the strong interaction into account has been used to fit themeasured correlation function. The effects of single and coupled channelwere explored. At the mean transverse mass m_T = 1.07 GeV, we obtain thevalues R = 4.09 +- 0.46 (stat.) +- 0.31 (sys) fm and lambda = 0.92 +-0.23 (stat) +- 0.13 (sys), where R and lambda are the invariant radiusand chaoticity par… more
Date: August 5, 2006
Creator: Abelev, B. I.; Adams, J.; Aggarwal, M. M.; Ahammed, Z.; Amonett, J.; Anderson, B. D. et al.
Partner: UNT Libraries Government Documents Department
open access

Biosynthesis of a Fully Functional Cyclotide inside Living Bacterial Cells

Description: The cyclotide MCoTI-II is a powerful trypsin inhibitor recently isolated from the seeds of Momordica cochinchinensis, a plant member of cucurbitaceae family. We report for the first time the in vivo biosynthesis of natively-folded MCoTI-II inside live E. coli cells. Our biomimetic approach involves the intracellular backbone cyclization of a linear cyclotide-intein fusion precursor mediated by a modified protein splicing domain. The cyclized peptide then spontaneously folds into its native conf… more
Date: April 5, 2007
Creator: Camarero, J A; Kimura, R H; Woo, Y; Cantor, J & Shekhtman, A
Partner: UNT Libraries Government Documents Department
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