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12.6 keV Kr K-alpha X-ray Source For High Energy Density Physics Experiments (open access)

12.6 keV Kr K-alpha X-ray Source For High Energy Density Physics Experiments

A high contrast 12.6 keV Kr K{alpha} source has been demonstrated on the petawatt-class Titan laser facility. The contrast ratio (K{alpha} to continuum) is 65, with a competitive ultra short pulse laser to x-ray conversion efficiency of 10{sup -5}. Filtered shadowgraphy indicates that the Kr K{alpha} and K{beta} x-rays are emitted from a roughly 1 x 2 mm emission volume, making this source suitable for area backlighting and scattering. Spectral calculations indicate a typical bulk electron temperature of 50-70 eV (i.e. mean ionization state 13-16), based on the observed ratio of K{alpha} to K{beta}. Kr gas jets provide a debris-free high energy K{alpha} source for time-resolved diagnosis of dense matter.
Date: April 22, 2008
Creator: Kugland, N.; Constantin, C. G.; Niemann, C.; Neumayer, P.; Chung, H.; Doppner, T. et al.
System: The UNT Digital Library
20-100 keV K(alpha) X-Ray Source Generation by Short Pulse High Intensity Lasers (open access)

20-100 keV K(alpha) X-Ray Source Generation by Short Pulse High Intensity Lasers

We are studying the feasibility of utilizing K{alpha} x-ray sources in the range of 20 to 100 keV as a backlighters for imaging various stages of implosions and high areal density planar samples driven by the NIF laser facility. The hard x-ray K{alpha} sources are created by relativistic electron plasma interactions in the target material after a radiation by short pulse high intensity lasers. In order to understand K{alpha} source characteristics such as production efficiency and brightness as a function of laser parameters, we have performed experiments using the 10 J, 100 fs JanUSP laser. We utilized single-photon counting spectroscopy and x-ray imaging diagnostics to characterize the K{alpha} source. We find that the K{alpha} conversion efficiency from the laser energy is {approx} 3 x 10{sup -4}.
Date: August 22, 2003
Creator: Park, H. S.; Koch, J. A.; Landen, O. L.; Phillips, T. W. & Goldsack, T.
System: The UNT Digital Library
62-TeV center of mass hadron collider with capability for super bunch beams (open access)

62-TeV center of mass hadron collider with capability for super bunch beams

A 60 TeV center of mass hadron collider is proposed, which has capability of using Superbunch beam. With Superbunch beam, the luminosity is expected to be increased by a factor of 20, compared with conventional acceleration using RF cavities. This hadron collider will be built in two stages with a low field magnet ring first and a high field magnet ring later in the same tunnel. The low field magnet rig will be built with Pipetron scheme, with 7 TeV and 7 TeV proton beams, making a 14 TeV center of mass energy high luminosity collider, using Superbunch beams. In the second stage 10 Tesla high field magnets with twin beams, will be installed. It also utilizes Superbunch beams, realizing high luminosity collider. To accelerate Superbunch beams, the barrier bucket and acceleration induction cells will be used, which are made of induction cells, utilizing FINEMET material. The core loss of the FINEMET is estimated for the whole collider is estimated. The synchrotron radiation of the collider is also estimated. Merits of Superbunch beams over RF bunched beams for the high energy experiments is described.
Date: August 22, 2001
Creator: Takayama, Ryuji Yamada and Ken
System: The UNT Digital Library
1982 THERMAL SHALLOW RESERVOIR TESTING (open access)

1982 THERMAL SHALLOW RESERVOIR TESTING

An extensive study of the Thermal Shallow Reservoir at The Geysers was performed in 1982 to improve our understanding of the source and flow patterns of steam in the shallow anomaly and how they relate to the Thermal 4 blowout. This project included gathering and analyzing pressure transient, enthalpy, tracer and chemical data and developing a reservoir model that was consistent with this data. Following the pressure transient testing and analysis, a convection-plume with lateral-flow model was proposed. Subsequent analysis of enthalpy, tracer and chemical data corroborated this model. The high flowrate wells--Thermal 4, Thermal 10, Thermal 11 and Magma 1--produce from the high-pressure, high-permeability upflow zone. The source of this upflow is a limited fracture system connecting the shallow anomaly with the underlying main reservoir. The outlying low-pressure, low-permeability wells are supplied by lateral flow of steam from the central area. The pressure gradient from the core to the periphery is caused by condensation in the flanks.
Date: January 22, 1985
Creator: Mogen, P.; Pittinger, L. & Magers, M.
System: The UNT Digital Library
2007 GRC on Cellulases and Cellulosomes (July 29-August 3, 2007) (open access)

2007 GRC on Cellulases and Cellulosomes (July 29-August 3, 2007)

Cellulose, a key component of the plant cell wall, comprises the most abundant source of organic carbon on the planet and its microbial degradation is of considerable biological and industrial importance. Indeed, the microbial degradation of cellulose and other plant structural polysaccharides is critical to the maintenance of the carbon cycle in terrestrial and marine microbial ecosystems, host invasion by several phytopathogens, and herbivore nutrition. While the enzymes that attack cellulose are already widely used in several biotechnology-based industries, the major future application of these biocatalysts is the conversion of plant biomass into bio-ethanol and other forms of energy. In that context, the 2007 Conference will present the latest breakthroughs in our understanding of the enzymology, structural biology and (meta)genomics underpinning the conversion of plant structural polysaccharides into fermentable sugars, both in natural and engineered processes. There is also an increased emphasis on the roles of other carbohydrate active enzymes in plant biomass conversion. The themes for the scientific sessions include: (1) crystallographic and biochemical analyses of enzyme structure and function; (2) molecular mechanisms underpinning enzyme catalysis, processivity and specificity; (3) functional and comparative analyses of carbohydrate binding modules and enzyme-substrate interactions; (4) directed evolution for the development of catalytically …
Date: September 22, 2008
Creator: Gray, Mark Morrison Nancy Ryan
System: The UNT Digital Library
2012 CELLULAR & MOLECULAR FUNGAL BIOLOGY GORDON RESEARCH CONFERENCE, JUNE 17 - 22, 2012 (open access)

2012 CELLULAR & MOLECULAR FUNGAL BIOLOGY GORDON RESEARCH CONFERENCE, JUNE 17 - 22, 2012

The Gordon Research Conference on CELLULAR & MOLECULAR FUNGAL BIOLOGY was held at Holderness School, Holderness New Hampshire, June 17 - 22, 2012. The 2012 Gordon Conference on Cellular and Molecular Fungal Biology (CMFB) will present the latest, cutting-edge research on the exciting and growing field of molecular and cellular aspects of fungal biology. Topics will range from yeast to filamentous fungi, from model systems to economically important organisms, and from saprophytes and commensals to pathogens of plants and animals. The CMFB conference will feature a wide range of topics including systems biology, cell biology and morphogenesis, organismal interactions, genome organisation and regulation, pathogenesis, energy metabolism, biomass production and population genomics. The Conference was well-attended with 136 participants. Gordon Research Conferences does not permit publication of meeting proceedings.
Date: June 22, 2012
Creator: Berman, Judith
System: The UNT Digital Library
2012 CHEMISTRY & PHYSICS OF GRAPHITIC CARBON MATERIALS GORDON RESEARCH CONFERENCE, JUNE 17-22, 2012 (open access)

2012 CHEMISTRY & PHYSICS OF GRAPHITIC CARBON MATERIALS GORDON RESEARCH CONFERENCE, JUNE 17-22, 2012

This conference will highlight the urgency for research on graphitic carbon materials and gather scientists in physics, chemistry, and engineering to tackle the challenges in this field. The conference will focus on scalable synthesis, characterization, novel physical and electronic properties, structure-properties relationship studies, and new applications of the carbon materials. Contributors
Date: June 22, 2012
Creator: Fertig, Herbert
System: The UNT Digital Library
3D-FHNet: Three-Dimensional Fusion Hierarchical Reconstruction Method for Any Number of Views (open access)

3D-FHNet: Three-Dimensional Fusion Hierarchical Reconstruction Method for Any Number of Views

Article proposes a three-dimensional fusion hierarchical reconstruction method that utilizes a multi-view feature combination method and a hierarchical prediction strategy to unify the single view and any number of multiple views 3D reconstructions.
Date: November 22, 2019
Creator: Lu, Qiang; Lu, Yiyang; Xiao, Mingjie; Yuan, Xiaohui & Jia, Wei
System: The UNT Digital Library
3D Mesh optimization methods for unstructured polyhedra: A progress report (open access)

3D Mesh optimization methods for unstructured polyhedra: A progress report

A mesh optimization scheme allows a Lagrangian code to run problems with extreme mesh distortion by reconfiguring node and zone connectivity as the problem evolves. We have developed some 3D mesh optimization operations and criteria for applying them. These are demonstrated in a 3D Free Lagrange code being developed at LLNL. In the simplest case of a mesh or mesh subregion composed purely of tetrahedra we can maintain a Delaunay tetrahedralization. For more interesting meshes, made up of general polyhedra, a suite of optimization operations and their respective application criteria have been developed.
Date: November 22, 1994
Creator: Miller, D. S. & Burton, D. E.
System: The UNT Digital Library
AA Fest General Circulation Model Development: Past, Present and Future. A Symposium in Honor of Professor Akio Arakawa (open access)

AA Fest General Circulation Model Development: Past, Present and Future. A Symposium in Honor of Professor Akio Arakawa

On January 20-22, 1998, ''AA Fest. A Symposium on General Circulation Model Development: Past, Present, and Future'' was held at the North West Campus Auditorium of University of California, Los Angeles, in honor of Professor Ako Arawaka. The symposium consisted of two-and-a-half-day technical presentations, along with a banquet in the opening evening and a reception during the poster session of the second evening.
Date: January 22, 1998
Creator: Ide, Kayo
System: The UNT Digital Library
Ab Initio Study of 40Ca with an Importance Truncated No-Core Shell Model (open access)

Ab Initio Study of 40Ca with an Importance Truncated No-Core Shell Model

We propose an importance truncation scheme for the no-core shell model, which enables converged calculations for nuclei well beyond the p-shell. It is based on an a priori measure for the importance of individual basis states constructed by means of many-body perturbation theory. Only the physically relevant states of the no-core model space are considered, which leads to a dramatic reduction of the basis dimension. We analyze the validity and efficiency of this truncation scheme using different realistic nucleon-nucleon interactions and compare to conventional no-core shell model calculations for {sup 4}He and {sup 16}O. Then, we present the first converged calculations for the ground state of {sup 40}Ca within no-core model spaces including up to 16{h_bar}{Omega}-excitations using realistic low-momentum interactions. The scheme is universal and can be easily applied to other quantum many-body problems.
Date: May 22, 2007
Creator: Roth, R & Navratil, P
System: The UNT Digital Library
Ab initio transport properties of nanostructures from maximally localized Wannier functions (open access)

Ab initio transport properties of nanostructures from maximally localized Wannier functions

Article on ab initio transport properties of nanostructures from maximally localized Wannier functions.
Date: January 22, 2004
Creator: Calzolari, Arrigo; Marzari, Nicola; Souza, Ivo & Buongiorno Nardelli, Marco
System: The UNT Digital Library
ABSOLUTE BUNCH LENGTH MEASUREMENTS AT THE ALS BY INCOHERENTSYNCHROTRON RADIATION FLUCTUATION ANALYSIS (open access)

ABSOLUTE BUNCH LENGTH MEASUREMENTS AT THE ALS BY INCOHERENTSYNCHROTRON RADIATION FLUCTUATION ANALYSIS

By analysing the pulse to pulse intensity fluctuations ofthe radiation emitted by a charge particle in the incoherent part of thespectrum, it is possible to extract information about the spatialdistribution of the beam. At the Advanced Light Source (ALS) of theLawrence Berkeley National Laboratory, we have developed and tested asimple scheme based on this principle that allows for the absolutemeasurement of the bunch length. A description of the method and theexperimental results are presented.
Date: June 22, 2007
Creator: Sannibale, Fernando; Zolotorev, Max S.; Filippetto, Daniele & Stupakov, Gennady V.
System: The UNT Digital Library
Absolute CH radical concentrations in rich low-pressure methane-oxygen-argon flames via cavity ringdown spectroscopy of the A transition (open access)

Absolute CH radical concentrations in rich low-pressure methane-oxygen-argon flames via cavity ringdown spectroscopy of the A transition

We measure cavity ringdown spectra of the A{sup 2}{Delta}-X{sup 2}II transition of the methylidyne (CH) radical in a series of rich low-pressure methane-oxygen-argon flames and demonstrate that the technique is sensitive, quantitative, and straightforward in its implementation and interpretation. As a line-of-sight technique, it complements imaging techniques, such as planar laser-induced fluorescence. Our results generally agree with chemical kinetic models for methane oxidation that have appeared in the literature, but suggest some refinements are necessary. Additional examination of the CH + O{sub 2} reaction rate as a function of temperature is advised. Our results are consistent with those of Derzy et al. using the C{sup 2}{Sigma}{sup +}-X{sup 2}II transition for stoichiometric, low-pressure flames which include nitrogen. Our results for rich flames, as with earlier experiments for singlet methylene, suggest that flame chemical kinetic models need to be adjusted to account for flame chemistry for stoichiometries richer than {phi} = 1.5.
Date: November 22, 1999
Creator: John W. Thomas, Jr & McIlroy, Andrew
System: The UNT Digital Library
ABSOLUTE POLARIZED H-JET POLARIMETER DEVELOPMENT FOR RHIC. (open access)

ABSOLUTE POLARIZED H-JET POLARIMETER DEVELOPMENT FOR RHIC.

Status of the H-jet polarimeter development is reviewed. The preliminary results of atomic beam intensity and density measurements are presented.
Date: September 22, 2003
Creator: ZELENSKI,A. BRAVAR,A. GRAHAM,D. HAEBERLI,W. MAKDISI,Y. MAHLER,G. NASS,A. RITTER,J. ET AL.
System: The UNT Digital Library
Actively Biased p-Channel MOSFET Studied with Scanning Capacitance Microscopy (open access)

Actively Biased p-Channel MOSFET Studied with Scanning Capacitance Microscopy

Scanning capacitance microscopy (SCM) was used to study the cross section of an operating p-channel MOSFET. We discuss the novel test structure design and the modifications to the SCM hardware that enabled us to perform SCM while applying dc bias voltages to operate the device. The results are compared with device simulations performed with DAVINCI.
Date: September 22, 1999
Creator: Nakakura, Craig Y.; Hetherington, Dale L.; Shaneyfelt, Marty R.; Dodd, Paul E. & De Wolf, P.
System: The UNT Digital Library
Adaptive optimization and control using neural networks (open access)

Adaptive optimization and control using neural networks

Recent work has demonstrated the ability of neural-network-based controllers to optimize and control machines with complex, non-linear, relatively unknown control spaces. We present a brief overview of neural networks via a taxonomy illustrating some capabilities of different kinds of neural networks. We present some successful control examples, particularly the optimization and control of a small-angle negative ion source.
Date: October 22, 1993
Creator: Mead, W. C.; Brown, S. K.; Jones, R. D.; Bowling, P. S. & Barnes, C. W.
System: The UNT Digital Library
An Adaptive Particle Filtering Approach to Tracking Modes in a Varying Shallow Ocean Environment (open access)

An Adaptive Particle Filtering Approach to Tracking Modes in a Varying Shallow Ocean Environment

The shallow ocean environment is ever changing mostly due to temperature variations in its upper layers (< 100m) directly affecting sound propagation throughout. The need to develop processors that are capable of tracking these changes implies a stochastic as well as an 'adaptive' design. The stochastic requirement follows directly from the multitude of variations created by uncertain parameters and noise. Some work has been accomplished in this area, but the stochastic nature was constrained to Gaussian uncertainties. It has been clear for a long time that this constraint was not particularly realistic leading a Bayesian approach that enables the representation of any uncertainty distribution. Sequential Bayesian techniques enable a class of processors capable of performing in an uncertain, nonstationary (varying statistics), non-Gaussian, variable shallow ocean. In this paper adaptive processors providing enhanced signals for acoustic hydrophonemeasurements on a vertical array as well as enhanced modal function estimates are developed. Synthetic data is provided to demonstrate that this approach is viable.
Date: March 22, 2011
Creator: Candy, J V
System: The UNT Digital Library
Adaptively Learning an Importance Function Using Transport Constrained Monte Carlo (open access)

Adaptively Learning an Importance Function Using Transport Constrained Monte Carlo

It is well known that a Monte Carlo estimate can be obtained with zero-variance if an exact importance function for the estimate is known. There are many ways that one might iteratively seek to obtain an ever more exact importance function. This paper describes a method that has obtained ever more exact importance functions that empirically produce an error that is dropping exponentially with computer time. The method described herein constrains the importance function to satisfy the (adjoint) Boltzmann transport equation. This constraint is provided by using the known form of the solution, usually referred to as the Case eigenfunction solution.
Date: June 22, 1998
Creator: Booth, T. E.
System: The UNT Digital Library
Addition of bromine as a diagnostic gas to inertial confinement fusion target microspheres (open access)

Addition of bromine as a diagnostic gas to inertial confinement fusion target microspheres

Currently, direct fuel rho r measurements on Inertial Confinement Fusion (ICF) targets by neutron activation of the argon tracer gas mixed with the DT fuel would require a 100 fold increase in neutron yield. Bromine, on the other hand, has excellent properties for neutron activation analysis at neutron yields of 10two' to 10/sup 8/, when present at an internal pressure of from 0.1 to 0.2 atmospheres. Bromine addition is accomplished in a 2 furnace system using the dried-gel method of microsphere production. An upper furnace operated at 1500/sup 0/C is separated from a lower furnace by a cooled zone. The lower furnace is filled with bromine gas and operated at approximately 1250/sup 0/C. The upper furnace is the glass production furnace. The cooled zone in between the upper and lower furnace is to prevent the hot bromine gas from rising into the upper furnace. The microspheres pass through the cooled zone and immediately into the 1250/sup 0/C bromine furnace where the bromine permeates into the spheres.
Date: August 22, 1980
Creator: Morrison, R. L.
System: The UNT Digital Library
Adherence to Exercise Programs in Older Adults: Informative Report (open access)

Adherence to Exercise Programs in Older Adults: Informative Report

This article focuses on filling information gaps regarding adherence to physical activity and exercise in the health care spectrum of older adults (OA) and an overview of the benefits of physical activity for OA. Exercise adherence in OA is a multifactorial problem encompassing many biopsychosocial factors. Factors affecting adherence in the OA include socioeconomic status, education level, living arrangements, health status, pacemakers, physical fitness, and depression. Improving adherence could have a significant impact on longevity, quality of life, and health care costs.
Date: January 22, 2019
Creator: Rivera-Torres, Solymar; Fahey, Thomas D. & Rivera, Miguel A.
System: The UNT Digital Library
Adjustable permanent quadrupoles for the next linear collider (open access)

Adjustable permanent quadrupoles for the next linear collider

The proposed Next Linear Collider (NLC) will require over 1400 adjustable quadrupoles between the main linacs' accelerator structures. These 12.7 mm bore quadrupoles will have a range of integrated strength from 0.6 to 138 Tesla, with a maximum gradient of 141 Tesla per meter, an adjustment range of +0 to {minus}20% and effective lengths from 324 mm to 972 mm. The magnetic center must remain stable to within 1 micron during the 20% adjustment. In an effort to reduce costs and increase reliability, several designs using hybrid permanent magnets have been developed. Four different prototypes have been built. All magnets have iron poles and use Samarium Cobalt to provide the magnetic fields. Two use rotating permanent magnetic material to vary the gradient, one uses a sliding shunt to vary the gradient and the fourth uses counter rotating magnets. Preliminary data on gradient strength, temperature stability, and magnetic center position stability are presented. These data are compared to an equivalent electromagnetic prototype.
Date: June 22, 2001
Creator: al., James T. Volk et
System: The UNT Digital Library
ADVANCED DIELECTRIC CONTINUUM MODELS OF SOLVATION, THEIR CONNECTION TO MICROSCOPIC SOLVENT MODELS, AND APPLICATION TO ELECTRON TRANSFER REACTIONS (open access)

ADVANCED DIELECTRIC CONTINUUM MODELS OF SOLVATION, THEIR CONNECTION TO MICROSCOPIC SOLVENT MODELS, AND APPLICATION TO ELECTRON TRANSFER REACTIONS

Some recent advances in dielectric continuum models for static and dynamic aspects of molecular solvation are discussed, and connections with molecular-level solvent models are noted. The traditional Born-Onsager-Kirkwood (BKO) model is compared to a more flexible model (the so-called frequency-resolved cavity model (FRCM)) which assigns distinct inner and outer solute cavities in accommodating, respectively, the inertialess (optical) and inertial solvent response. Sample calculations of solvent reorganization energy ({lambda}{sub s}) are presented for various thermal and optical electron transfer (ET) processes, based on self-consistent reaction field models using molecular orbital (MO) or configuration interaction (CI) solvent wave functions.
Date: June 22, 2000
Creator: Rostov, I. V.; Basilevsky, M. V. & Newton, M. D.
System: The UNT Digital Library
Advances in Normal Conducting Accelerator Technology from the X-Band Linear Collider Program (open access)

Advances in Normal Conducting Accelerator Technology from the X-Band Linear Collider Program

In the mid-1990's, groups at SLAC and KEK began dedicated development of X-band (11.4 GHz) rf technology for a next generation, TeV-scale linear collider. The choice of a relatively high frequency, four times that of the SLAC 50 GeV Linac, was motivated by the cost benefits of having lower rf energy per pulse (hence fewer rf sources) and reasonable efficiencies at high gradients (hence shorter linacs). To realize such savings, however, requires operation at gradients and peak powers much higher than that hitherto achieved. During the past twelve years, these challenges were met through innovations on several fronts. This paper reviews these achievements, which include developments in the generation and transport of high power rf, and new insights into high gradient limitations.
Date: June 22, 2005
Creator: Adolphsen, C.
System: The UNT Digital Library