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Preface to International Workshop on X-ray Mirror Design, Fabrication, and Metrology (open access)

Preface to International Workshop on X-ray Mirror Design, Fabrication, and Metrology

The International Workshop on X-Ray Mirror Design, Fabrication, and Metrology (IWXM), Osaka, Japan, was held as a satellite meeting of the Conference on Synchrotron Radiation Instrumentation (SRI) 2009, Melbourne, Australia, in October, 2009. The workshop was organized by a collaboration of scientists from a number of leading synchrotron institutions and universities around the World, such as Osaka University, SPring-8, KEK (Japan), ALS, APS and NSLS (USA), ELETTRA (Italy), ESRF, Synchrotron SOLEIL (France), BESSY (Germany), Diamond (UK), SSRF (China), NSRRC (Taiwan) and PAL (Korea). The workshop followed a series of parallel workshops focused on metrology (1st, 2nd and 3rd International Workshop on Metrology for X-ray and Neutron Optics) and on active X-ray optics (1st and 2nd X-ray and XUV Active Optics Workshop, ACTOP06 and ACTOP08) and included the 3rd workshop on X-ray and EUV active optics (ACTOP09). The workshop brought together more than 100 participants: manufacturers, optical and mechanical engineers, designers, and users of X-ray optics; allowing for free exchange of ideas, highlighting of existing problems and challenges, and searching for ways to improve existing instrumentation for sub-microradian and sub-nanometer accuracy. A visit to the Osaka University mirror fabrication laboratory, SPring-8, and the X-ray free electron laser (XFEL) facility was included …
Date: April 20, 2010
Creator: Yamauchi, Kazuto; Yashchuk, Valeriy V. & Cocco, Daniele
System: The UNT Digital Library
The Northwest Geysers EGS Demonstration Project Phase 1: Pre-stimulation coupled geomechanical modeling to guide stimulation and monitoring plans (open access)

The Northwest Geysers EGS Demonstration Project Phase 1: Pre-stimulation coupled geomechanical modeling to guide stimulation and monitoring plans

This paper presents activities and results associated with Phase 1 (pre-stimulation phase) of an Enhanced Geothermal System (EGS) demonstration project at the northwest part of The Geysers geothermal field, California. The paper presents development of a 3-D geological model, coupled thermal-hydraulic-mechanical (THM) modeling of proposed stimulation injection as well as current plans for stimulation and monitoring of the site. The project aims at creating an EGS by directly and systematically injecting cool water at relatively low pressure into a known High Temperature (about 280 to 350 C) Zone (HTZ) located under the conventional (240 C) steam reservoir at depths of {approx}3 km. Accurate micro-earthquake monitoring initiated before the start of the injection will be used as a tool for tracking the development of the EGS and monitoring changes in microseismicity. We first analyzed historic injection and micro-earthquake data from an injection well (Aidlin 11) located about 3 miles to the west of the new EGS demonstration area. Thereafter, we used the same modeling approach to predict the likely extent of the zone of enhanced permeability for a proposed initial injection in two wells (Prati State 31 and Prati 32) at the new EGS demonstration area. Our modeling indicates that the …
Date: October 20, 2010
Creator: Rutqvist, J.; Dobson, P. F.; Oldenburg, C. M.; Garcia, J. & Walters, M.
System: The UNT Digital Library
Gamma Spectrum from Neutron Capture on Tungsten Isotopes (open access)

Gamma Spectrum from Neutron Capture on Tungsten Isotopes

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Date: May 20, 2010
Creator: Hurst, A. M.; Summers, N. C.; Sleaford, B.; Firestone, R.; Belgya, T. & Revay, Z. S.
System: The UNT Digital Library
Heterogeneous nucleation of ice on anthropogenic organic particles collected in Mexico City (open access)

Heterogeneous nucleation of ice on anthropogenic organic particles collected in Mexico City

This study reports on heterogeneous ice nucleation activity of predominantly organic (or coated with organic material) anthropogenic particles sampled within and around the polluted environment of Mexico City. The onset of heterogeneous ice nucleation was observed as a function of particle temperature (Tp), relative humidity (RH), nucleation mode, and particle chemical composition which is influenced by photochemical atmospheric aging. Particle analyses included computer controlled scanning electron microscopy with energy dispersive analysis of X-rays (CCSEM/EDX) and scanning transmission X-ray microscopy with near edge X-ray absorption fine structure spectroscopy (STXM/NEXAFS). In contrast to most laboratory studies employing proxies of organic aerosol, we show that anthropogenic organic particles collected in Mexico City can potentially induce ice nucleation at experimental conditions relevant to cirrus formation. The results suggest a new precedent for the potential impact of organic particles on ice cloud formation and climate.
Date: June 20, 2010
Creator: Knopf, D. A.; Wang, B.; Laskin, A.; Moffet, R. C. & Gilles, M. K.
System: The UNT Digital Library
A NORMETEX MODEL 15 M3/HR WATER VAPOR PUMPING TEST (open access)

A NORMETEX MODEL 15 M3/HR WATER VAPOR PUMPING TEST

Tests were performed using a Model 15 m{sup 3}/hr Normetex vacuum pump to determine if pump performance degraded after pumping a humid gas stream. An air feed stream containing 30% water vapor was introduced into the pump for 365 hours with the outlet pressure of the pump near the condensation conditions of the water. Performance of the pump was tested before and after the water vapor pumping test and indicated no loss in performance of the pump. The pump also appeared to tolerate small amounts of condensed water of short duration without increased noise, vibration, or other adverse indications. The Normetex pump was backed by a dual-head diaphragm pump which was affected by the condensation of water and produced some drift in operating conditions during the test.
Date: December 20, 2010
Creator: Klein, J.; Fowley, M. & Steeper, T.
System: The UNT Digital Library
Daemen Alternative Energy/Geothermal Technologies Demonstration Program Erie County (open access)

Daemen Alternative Energy/Geothermal Technologies Demonstration Program Erie County

The purpose of the Daemen Alternative Energy/Geothermal Technologies Demonstration Project is to demonstrate the use of geothermal technology as model for energy and environmental efficiency in heating and cooling older, highly inefficient buildings. The former Marian Library building at Daemen College is a 19,000 square foot building located in the center of campus. Through this project, the building was equipped with geothermal technology and results were disseminated. Gold LEED certification for the building was awarded. 1) How the research adds to the understanding of the area investigated. This project is primarily a demonstration project. Information about the installation is available to other companies, organizations, and higher education institutions that may be interested in using geothermal energy for heating and cooling older buildings. 2) The technical effectiveness and economic feasibility of the methods or techniques investigated or demonstrated. According to the modeling and estimates through Stantec, the energy-efficiency cost savings is estimated at 20%, or $24,000 per year. Over 20 years this represents $480,000 in unrestricted revenue available for College operations. See attached technical assistance report. 3) How the project is otherwise of benefit to the public. The Daemen College Geothermal Technologies Ground Source Heat Pumps project sets a standard for …
Date: May 20, 2010
Creator: Robert C. Beiswanger, Jr.
System: The UNT Digital Library
Automatic Fault Characterization via Abnormality-Enhanced Classification (open access)

Automatic Fault Characterization via Abnormality-Enhanced Classification

Enterprise and high-performance computing systems are growing extremely large and complex, employing hundreds to hundreds of thousands of processors and software/hardware stacks built by many people across many organizations. As the growing scale of these machines increases the frequency of faults, system complexity makes these faults difficult to detect and to diagnose. Current system management techniques, which focus primarily on efficient data access and query mechanisms, require system administrators to examine the behavior of various system services manually. Growing system complexity is making this manual process unmanageable: administrators require more effective management tools that can detect faults and help to identify their root causes. System administrators need timely notification when a fault is manifested that includes the type of fault, the time period in which it occurred and the processor on which it originated. Statistical modeling approaches can accurately characterize system behavior. However, the complex effects of system faults make these tools difficult to apply effectively. This paper investigates the application of classification and clustering algorithms to fault detection and characterization. We show experimentally that naively applying these methods achieves poor accuracy. Further, we design novel techniques that combine classification algorithms with information on the abnormality of application behavior to …
Date: December 20, 2010
Creator: Bronevetsky, G; Laguna, I & de Supinski, B R
System: The UNT Digital Library
Genome-wide analysis of promoter architecture in Drosophila melanogaster (open access)

Genome-wide analysis of promoter architecture in Drosophila melanogaster

Core promoters are critical regions for gene regulation in higher eukaryotes. However, the boundaries of promoter regions, the relative rates of initiation at the transcription start sites (TSSs) distributed within them, and the functional significance of promoter architecture remain poorly understood. We produced a high-resolution map of promoters active in the Drosophila melanogaster embryo by integrating data from three independent and complementary methods: 21 million cap analysis of gene expression (CAGE) tags, 1.2 million RNA ligase mediated rapid amplification of cDNA ends (RLMRACE) reads, and 50,000 cap-trapped expressed sequence tags (ESTs). We defined 12,454 promoters of 8037 genes. Our analysis indicates that, due to non-promoter-associated RNA background signal, previous studies have likely overestimated the number of promoter-associated CAGE clusters by fivefold. We show that TSS distributions form a complex continuum of shapes, and that promoters active in the embryo and adult have highly similar shapes in 95% of cases. This suggests that these distributions are generally determined by static elements such as local DNA sequence and are not modulated by dynamic signals such as histone modifications. Transcription factor binding motifs are differentially enriched as a function of promoter shape, and peaked promoter shape is correlated with both temporal and spatial …
Date: October 20, 2010
Creator: Hoskins, Roger A.; Landolin, Jane M.; Brown, James B.; Sandler, Jeremy E.; Takahashi, Hazuki; Lassmann, Timo et al.
System: The UNT Digital Library
Wavefront-sensor-based electron density measurements for laser-plasma accelerators (open access)

Wavefront-sensor-based electron density measurements for laser-plasma accelerators

Characterization of the electron density in laser produced plasmas is presented using direct wavefront analysis of a probe laser beam. The performance of a laser-driven plasma-wakefield accelerator depends on the plasma wavelength, hence on the electron density. Density measurements using a conventional folded-wave interferometer and using a commercial wavefront sensor are compared for different regimes of the laser-plasma accelerator. It is shown that direct wavefront measurements agree with interferometric measurements and, because of the robustness of the compact commercial device, have greater phase sensitivity, straightforward analysis, improving shot-to-shot plasma-density diagnostics.
Date: February 20, 2010
Creator: Plateau, Guillaume; Matlis, Nicholas; Geddes, Cameron; Gonsalves, Anthony; Shiraishi, Satomi; Lin, Chen et al.
System: The UNT Digital Library
Impact of intrinsic localized modes of atomic motion on materials properties (open access)

Impact of intrinsic localized modes of atomic motion on materials properties

Recent neutron and x-ray scattering measurements show intrinsic localized modes (ILMs) in metallic uranium and ionic sodium iodide. Here, the role ILMs play in the behavior of these materials is examined. With the thermal activation of ILMs, thermal expansion is enhanced, made more anisotropic, and, at a microscopic level, becomes inhomogeneous. Interstitial diffusion, ionic conductivity, the annealing rate of radiation damage, and void growth are all influenced by ILMs. The lattice thermal conductivity is suppressed above the ILM activation temperature while no impact is observed in the electrical conductivity. This complement of transport properties suggests that ILMs could improve thermoelectric performance. Ramifications also include thermal ratcheting, a transition from brittle to ductile fracture, and possibly a phase transformation in uranium.
Date: January 20, 2010
Creator: Manley, M E
System: The UNT Digital Library
Double Photoionization of excited Lithium and Beryllium (open access)

Double Photoionization of excited Lithium and Beryllium

We present total, energy-sharing and triple differential cross sections for one-photon, double ionization of lithium and beryllium starting from aligned, excited P states. We employ a recently developed hybrid atomic orbital/ numerical grid method based on the finite-element discrete-variable representation and exterior complex scaling. Comparisons with calculated results for the ground-state atoms, as well as analogous results for ground-state and excited helium, serve to highlight important selection rules and show some interesting effects that relate to differences between inter- and intra-shell electron correlation.
Date: May 20, 2010
Creator: Yip, Frank L.; McCurdy, C. William & Rescigno, Thomas N.
System: The UNT Digital Library
Design Of JET ELM Control Coils For Operation At 350 C (open access)

Design Of JET ELM Control Coils For Operation At 350 C

A study has confirmed the feasibility of designing, fabricating and installing resonant magnetic field perturbation (RMP) coils in JET1 with the objective of controlling edge localized modes (ELM). A system of two rows of in-vessel coils, above the machine midplane, has been chosen as it not only can investigate the physics of and achieve the empirical criteria for ELM suppression, but also permits variation of the spectra allowing for comparison with other experiments. These coils present several engineering challenges. Conditions in JET necessitate the installation of these coils via remote handling, which will impose weight, dimensional and logistical limitations. And while the encased coils are designed to be conventionally wound and bonded, they will not have the usual benefit of active cooling. Accordingly, coil temperatures are expected to reach 350 C during bakeout as well as during plasma operations. These elevated temperatures are beyond the safe operating limits of conventional OFHC copper and the epoxies that bond and insulate the turns of typical coils. This has necessitated the use of an alternative copper alloy conductor C18150 (CuCrZr). More importantly, an alternative to epoxy had to be found. An R&D program was initiated to find the best available insulating and bonding …
Date: September 20, 2010
Creator: Zatz, I. J.; Brooks, A.; Cole, M.; Neilson, G. H.; Lowry, C.; Mardenfeld, M. et al.
System: The UNT Digital Library
Enhanced Electron Efficiency in an X-Ray Diode (open access)

Enhanced Electron Efficiency in an X-Ray Diode

The goal for this research is to optimize the XRD structure and usage configurations and increase the efficiency of the XRD. This research was successful in optimizing the XRD structure and usage configurations, thus creating a high efficiency XRD. Best efficiency occurs when there is an angle between the photocathode and incident X-rays.
Date: May 20, 2010
Creator: K. Sun, L. MacNeil
System: The UNT Digital Library
Use of Hydrogen Getters for Ensuring Safe Storage of Plutonium-Bearing Materials at the Savannah River Site (open access)

Use of Hydrogen Getters for Ensuring Safe Storage of Plutonium-Bearing Materials at the Savannah River Site

Plutonium oxide left over from the 3013 destructive surveillance process is ultimately disposed of as waste. Therefore, this material is not re-stabilized and packaged to meet the requirements of DOE-STD-3013. Instead, it is stored on an interim basis in compliance with the interim safe storage criteria issued by DOE in January 1996. One of the safe storage criteria requires actions to be taken to minimize the formation or accumulation of flammable gases inside the storage container. Personnel responsible for the safe storage of the material have chosen to use a polymer-based, ambient air compatible hydrogen 'getter' to prevent the formation of hydrogen gas inside the storage container and thus prevent the formation of a flammable gas mixture. This paper briefly describes the method in which the getter performs its functions. More importantly, this paper presents the results of the testing that has been performed to characterize the bounding effects of aging and demonstrate the use of the getter for long-term storage. In addition, the favorable results of a post-storage analysis of actual getter material are presented and compared with bounding predictions. To date, bounding test results have shown that after 18 months of continuous storage and 39 months of total …
Date: May 20, 2010
Creator: Woodsmall, T.; Hackney, B. & Traver, L.
System: The UNT Digital Library
THE EFFECT OF CO ON HYDROGEN PERMEATION THROUGH PD AND INTERNALLY OXIDIZED AND UN-OXIDIZED PD ALLOY MEMBRANES (open access)

THE EFFECT OF CO ON HYDROGEN PERMEATION THROUGH PD AND INTERNALLY OXIDIZED AND UN-OXIDIZED PD ALLOY MEMBRANES

The H permeation of internally oxidized Pd alloy membranes such as Pd-Al and Pd-Fe, but not Pd-Y alloys, is shown to be more resistant to inhibition by CO(g) as compared to Pd or un-oxidized Pd alloy membranes. The increased resistance to CO is found to be greater at 423 K than at 473 K or 523 K. In these experiments CO was pre-adsorbed onto the membranes and then CO-free H{sub 2} was introduced to initiate the H permeation.
Date: October 20, 2010
Creator: Shanahan, K.; Flanagan, T. & Wang, D.
System: The UNT Digital Library
Shielding Studies for Superconducting RF Cavities at Fermilab (open access)

Shielding Studies for Superconducting RF Cavities at Fermilab

A semi-empirical method that allows us to predict intensity of generated field emission in superconducting RF cavities is described. Spatial, angular and energy distributions of the generated radiation are calculated with the FISHPACT code. The Monte Carlo code MARS15 is used for modeling the radiation transport in matter. A comparison with dose rate measurements performed in the Fermilab Vertical Test Facility for ILC-type cavities with accelerating gradients up to 35 MV/m is presented as well.
Date: July 20, 2010
Creator: Ginsburg, Camille & Rakhno, Igor
System: The UNT Digital Library
A Linear Tetranuclear Dysprosium(III) Compound Showing Single-Molecule Magnet Behavior (open access)

A Linear Tetranuclear Dysprosium(III) Compound Showing Single-Molecule Magnet Behavior

Although magnetic measurements reveal a single-relaxation time for a linear tetranuclear Dy(III) compound, the wide distribution of the relaxation time observed clearly suggests the presence of two slightly different anisotropic centres, therefore opening new avenues for investigating the relaxation dynamics of lanthanide aggregates.
Date: April 20, 2010
Creator: Ke, Hongshan; Xu, Gong Feng; Guo, Yun-Nan; Gamez, Patrick; Beavers, Christine M; Teat, Simon J et al.
System: The UNT Digital Library
MPI-hybrid Parallelism for Volume Rendering on Large, Multi-core Systems (open access)

MPI-hybrid Parallelism for Volume Rendering on Large, Multi-core Systems

This work studies the performance and scalability characteristics of"hybrid'" parallel programming and execution as applied to raycasting volume rendering -- a staple visualization algorithm -- on a large, multi-core platform. Historically, the Message Passing Interface (MPI) has become the de-facto standard for parallel programming and execution on modern parallel systems. As the computing industry trends towards multi-core processors, with four- and six-core chips common today and 128-core chips coming soon, we wish to better understand how algorithmic and parallel programming choices impact performance and scalability on large, distributed-memory multi-core systems. Our findings indicate that the hybrid-parallel implementation, at levels of concurrency ranging from 1,728 to 216,000, performs better, uses a smaller absolute memory footprint, and consumes less communication bandwidth than the traditional, MPI-only implementation.
Date: March 20, 2010
Creator: Howison, Mark; Bethel, E. Wes & Childs, Hank
System: The UNT Digital Library
Effective thermal boundary resistance from thermal decoupling of magnons and phonons in SrRuO3 thin films (open access)

Effective thermal boundary resistance from thermal decoupling of magnons and phonons in SrRuO3 thin films

We use the time-resolved magneto-optical Kerr effect (TRMOKE) to measure the local temperature and heat flow dynamics in ferromagnetic SrRuO3 thin films. After heating by a pump pulse, the film temperature decays exponentially, indicating that the heat flow out of the film is limited by the film/substrate interface. We show that this behavior is consistent with an effective boundary resistance resulting from disequilibrium between the spin and phonon temperatures in the film.
Date: January 20, 2010
Creator: Langner, M. C.; Kantner, C. L. S.; Chu, Y. H.; Martin, L. M.; Yu, P.; Ramesh, R. et al.
System: The UNT Digital Library
Compressive auto-indexing in femtosecond nanocrystallography (open access)

Compressive auto-indexing in femtosecond nanocrystallography

Ultrafast nanocrystallography has the potential to revolutionize biology by enabling structural elucidation of proteins for which it is possible to grow crystals with 10 or fewer unit cells. The success of nanocrystallography depends on robust orientation-determination procedures that allow us to average diffraction data from multiple nanocrystals to produce a 3D diffraction data volume with a high signal-to-noise ratio. Such a 3D diffraction volume can then be phased using standard crystallographic techniques."Indexing" algorithms used in crystallography enable orientation determination of a diffraction data from a single crystal when a relatively large number of reflections are recorded. Here we show that it is possible to obtain the exact lattice geometry from a smaller number of measurements than standard approaches using a basis pursuit solver.
Date: September 20, 2010
Creator: Maia, Filipe; Yang, Chao & Marchesini, Stefano
System: The UNT Digital Library
Laser Technology for Precision Monoenergetic Gamma-Ray Source R&D at Llnl (open access)

Laser Technology for Precision Monoenergetic Gamma-Ray Source R&D at Llnl

Generation of mono-energetic, high brightness gamma-rays requires state of the art lasers to both produce a low emittance electron beam in the linac and high intensity, narrow linewidth laser photons for scattering with the relativistic electrons. Here, we overview the laser systems for the 3rd generation Monoenergetic Gamma-ray Source (MEGa-ray) currently under construction at Lawrence Livermore National Lab (LLNL). We also describe a method for increasing the efficiency of laser Compton scattering through laser pulse recirculation. The fiber-based photoinjector laser will produce 50 {micro}J temporally and spatially shaped UV pulses at 120 Hz to generate a low emittance electron beam in the X-band RF photoinjector. The interaction laser generates high intensity photons that focus into the interaction region and scatter off the accelerated electrons. This system utilizes chirped pulse amplification and commercial diode pumped solid state Nd:YAG amplifiers to produce 0.5 J, 10 ps, 120 Hz pulses at 1064 nm and up to 0.2 J after frequency doubling. A single passively mode-locked Ytterbium fiber oscillator seeds both laser systems and provides a timing synch with the linac.
Date: April 20, 2010
Creator: Shverdin, M. Y.; Bayramian, A.; Albert, F.; Anderson, S. G.; Betts, S. M.; Chu, T. S. et al.
System: The UNT Digital Library
Developmental long trace profiler using optimally aligned mirror based pentaprism (open access)

Developmental long trace profiler using optimally aligned mirror based pentaprism

A low-budget surface slope measuring instrument, the Developmental Long Trace Profiler (DLTP), was recently brought into operation at the Advanced Light Source Optical Metrology Laboratory. The instrument is based on a precisely calibrated autocollimator and a movable pentaprism. The capability of the DLTP to achieve sub-microradian surface slope metrology has been verified via cross-comparison measurements with other high-performance slope measuring instruments when measuring the same high-quality test optics. In the present work, a further improvement of the DLTP is achieved by replacing the existing bulk pentaprism with a specially designed mirror based pentaprism. A mirror based pentaprism offers the possibility to eliminate systematic errors introduced by inhomogeneity of the optical material and fabrication imperfections of a bulk pentaprism. We provide the details of the mirror based pentaprism design and describe an original experimental procedure for precision mutual alignment of the mirrors. The algorithm of the alignment procedure and its efficiency are verified with rigorous ray tracing simulations. Results of measurements of a spherically curved test mirror and a flat test mirror using the original bulk pentaprism are compared with measurements using the new mirror based pentaprism, demonstrating the improved performance.
Date: December 20, 2010
Creator: Barber, Samuel K.; Morrison, Gregory Y.; Yashchuk, Valeriy V.; Gubarev, Mikhail V.; Geckeler, Ralf D.; Buchheim, Jana et al.
System: The UNT Digital Library
Pair-distribution function analysis of the structural valence transition in Cp{sub 2}{sup *}Yb(4,4'-Me{sub 2}-bipy) (open access)

Pair-distribution function analysis of the structural valence transition in Cp{sub 2}{sup *}Yb(4,4'-Me{sub 2}-bipy)

The Cp{sup ∗}{sub 2} Yb(L) class of compounds, where Cp{sup ∗}=pentamethylcyclopentadienyl = C{sub 5}Me{sub 5} and L is either a 1,4-diazabutadiene or bipy = 2,2′-bipyridine related ligand, have provided excellent analogies to the Kondo state on the nanoscale. Cp{sup ∗}{sub 2} Yb(4,4′-Me{sub 2}-bipy) furthers this analogy by demonstrating a valence transition as the sample is cooled below 200 K. Here, pair-distribution function (PDF) analysis of x-ray powder diffraction data demonstrate that the Cp{sup ∗}{sub 2}Yb(4,4′-Me{sub 2}-bipy) molecule is virtually unchanged through the valence transition. However, the molecule’s stacking arrangement is altered through the valence transition.
Date: July 20, 2010
Creator: Booth, C H; Bauer, E D; Bozin, E S; Billinge, S J L & Walter, M D
System: The UNT Digital Library