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Structural and electronic properties of carbon nanotube tapers

Description: Article on structural and electronic properties of carbon nanotube tapers, a set of nanostructures comprised of straight tubular sections with decreasing diameters, joined to each other via conical funnels and terminated with a hemispherical cap.
Date: October 29, 2001
Creator: Meunier, Vincent; Buongiorno Nardelli, Marco; Roland, Christopher & Bernholc, Jerry
Partner: UNT College of Arts and Sciences
open access

LMFBR fuel component costs

Description: A significant portion of the cost of fabricating LMFBR fuels is in the non-fuel components such as fuel pin cladding, fuel assembly ducts and end fittings. The contribution of these to fuel fabrication costs, based on FFTF experience and extrapolated to large LMFBR fuel loadings, is discussed. The extrapolation considers the expected effects of LMFBR development programs in progress on non-fuel component costs.
Date: October 29, 1981
Creator: Epperson, E.M.; Borisch, R.R. & Rice, L.H.
Partner: UNT Libraries Government Documents Department
open access

A Compact Linac for Proton Therapy Based on a Dielectric Wall Accelerator

Description: A novel compact CT-guided intensity modulated proton radiotherapy (IMPT) system is described. The system is being designed to deliver fast IMPT so that larger target volumes and motion management can be accomplished. The system will be ideal for large and complex target volumes in young patients. The basis of the design is the dielectric wall accelerator (DWA) system being developed at the Lawrence Livermore National Laboratory (LLNL). The DWA uses fast switched high voltage transmission lines … more
Date: October 29, 2007
Creator: Caporaso, G. J.; Mackie, T. R.; Sampayan, S.; Chen, Y.; Wang, L.; Blackfield, D. et al.
Partner: UNT Libraries Government Documents Department
open access

CONSTRAINT EFFECT IN FRACTURE WHAT IS IT

Description: The meaning of the phrase 'constraint effect in fracture' has changed in the past two decades from 'contained plasticity' to a broader description of 'dependence of fracture toughness value on geometry of test specimen or structure'. This paper will first elucidate the fundamental mechanics reasons for the apparent 'constraint effects in fracture', followed by outlining a straightforward approach to overcoming this problem in both brittle (elastic) and ductile (elastic-plastic) fracture. It is … more
Date: October 29, 2008
Creator: Lam, P & Prof. Yuh J. Chao, P
Partner: UNT Libraries Government Documents Department
open access

A High-Speed Detector System for X-ray Fluorescence Microprobes.

Description: We have developed a high-speed system for collecting x-ray fluorescence microprobe data, based on ASICs developed at BNL and high-speed processors developed by CSIRO. The system can collect fluorescence data in a continuous raster scan mode, and present elemental images in real time using Ryan's Dynamic Analysis algorithm. We will present results from a 32-element prototype array illustrating the concept. The final instrument will have 384 elements arranged in a square array around a central ho… more
Date: October 29, 2006
Creator: Siddons, P. D.; Dragone, A.; De Geronimo, G.; Kuczewski, A. & Kuczewski, J.
Partner: UNT Libraries Government Documents Department
open access

X-Ray Active Matrix Pixel Sensors Basedon J-FET Technology Developed for the Linac Coherent Light Source.

Description: An X-ray Active Matrix Pixel Sensor (XAMPS) is being developed for recording data for the X-ray Pump Probe experiment at the Linac Coherent Light Source (LCLS). Special attention has to be paid to some technological challenges that this design presents. New processes were developed and refined to address problems encountered during previous productions of XAMPS. The development of these critical steps and corresponding tests results are reported here.
Date: October 29, 2007
Creator: Carini, G. A.; Chen, W.; Li, Z.; Rehak, P. & Siddons, D. P.
Partner: UNT Libraries Government Documents Department
open access

In-situ X-ray photoelectron spectroscopy studies of water on metals and oxides at ambient conditions

Description: X-ray photoelectron spectroscopy (XPS) is a powerful tool for surface and interface analysis, providing the elemental composition of surfaces and the local chemical environment of adsorbed species. Conventional XPS experiments have been limited to ultrahigh vacuum (UHV) conditions due to a short mean free path of electrons in a gas phase. The recent advances in instrumentation coupled with third-generation synchrotron radiation sources enables in-situ XPS measurements at pressures above 5 Torr.… more
Date: October 29, 2007
Creator: Salmeron, Miquel; Yamamoto, S.; Bluhm, H.; Andersson, K.; Ketteler, G.; Ogasawara, H. et al.
Partner: UNT Libraries Government Documents Department
open access

Effect of Random Clustering on Surface Damage Density Estimates

Description: Identification and spatial registration of laser-induced damage relative to incident fluence profiles is often required to characterize the damage properties of laser optics near damage threshold. Of particular interest in inertial confinement laser systems are large aperture beam damage tests (>1cm{sup 2}) where the number of initiated damage sites for {phi}>14J/cm{sup 2} can approach 10{sup 5}-10{sup 6}, requiring automatic microscopy counting to locate and register individual damage si… more
Date: October 29, 2007
Creator: Matthews, M J & Feit, M D
Partner: UNT Libraries Government Documents Department
open access

Inelastic final-state interaction

Description: The final-state interaction in multichannel decay processes is systematically studied with application to B decay in mind. Since the final-state interaction is intrinsically interwoven with the decay interaction in this case, no simple phase theorem like"Watson's theorem" holds for experimentally observed final states. We first examine in detail the two-channel problem as a toy-model to clarify the issues and to remedy common mistakes made in earlier literature. Realistic multicha… more
Date: October 29, 2007
Creator: Suzuki, Mahiko & Suzuki, Mahiko
Partner: UNT Libraries Government Documents Department
open access

Downstream Intensification Effects Associated with CO2 Laser Mitigation of Fused Silica

Description: Mitigation of 351nm laser-induced damage sites on fused silica exit surfaces by selective CO{sub 2} treatment has been shown to effectively arrest the exponential growth responsible for limiting the lifetime of optics in high-fluence laser systems. However, the perturbation to the optical surface profile following the mitigation process introduces phase contrast to the beam, causing some amount of downstream intensification with the potential to damage downstream optics. Control of the laser tr… more
Date: October 29, 2007
Creator: Matthews, M. J.; Bass, I. L.; Guss, G. M.; Widmayer, C. C. & Ravizza, F. L.
Partner: UNT Libraries Government Documents Department
open access

Growth of laser damage in fused silica: diameter to depth ratio

Description: Growth of laser initiated damage plays a major role in determining optics lifetime in high power laser systems. Previous measurements have established that the lateral diameter grows exponentially. Knowledge of the growth of the site in the propagation direction is also important, especially so when considering techniques designed to mitigate damage growth, where it is required to reach all the subsurface damage. In this work, we present data on both the diameter and the depth of a growing exit… more
Date: October 29, 2007
Creator: Norton, M. A.; Adams, J. J.; Carr, C. W.; Donohue, E. E.; Feit, M. D.; Hackel, R. P. et al.
Partner: UNT Libraries Government Documents Department
open access

Design for a High Energy Density Kelvin-Helmholtz Experiment

Description: While many high energy density physics (HEDP) Rayleigh-Taylor and Richtmyer-Meshkov instability experiments have been fielded as part of basic HEDP and astrophysics studies, not one HEDP Kelvin-Helmholtz (KH) experiment has been successfully performed. Herein, a design for a novel HEDP x-ray driven KH experiment is presented along with supporting radiation-hydrodynamic simulation and theory.
Date: October 29, 2007
Creator: Hurricane, O A
Partner: UNT Libraries Government Documents Department
open access

SRNL PARTICIPATION IN THE MULTI-SCALE ENSEMBLE EXERCISES

Description: Consequence assessment during emergency response often requires atmospheric transport and dispersion modeling to guide decision making. A statistical analysis of the ensemble of results from several models is a useful way of estimating the uncertainty for a given forecast. ENSEMBLE is a European Union program that utilizes an internet-based system to ingest transport results from numerous modeling agencies. A recent set of exercises required output on three distinct spatial and temporal scales.… more
Date: October 29, 2007
Creator: Buckley, R
Partner: UNT Libraries Government Documents Department
open access

Recent Work in Multiphase Flow at NETL

Description: No abstract - only slideshow attached
Date: October 29, 2007
Creator: Syamlal, Madhava
Partner: UNT Libraries Government Documents Department
open access

LIGHT INDUCED TELLURIUM ENRICHMENT ON CDZNTE CRYSTALSURFACES DETECTED BY RAMAN SPECTROSCOPY

Description: Synthetic CdZnTe or 'CZT' crystals can be grown under controlled conditions to produce high quality crystals to be used as room temperature radiation detectors. Even the best crystal growth methods result in defects, such as tellurium secondary phases, that affect the crystal's performance. In this study, CZT crystals were analyzed by micro Raman spectroscopy. The growth of Te rich areas on the surface was induced by low powered lasers. The growth was observed versus time with low power Raman s… more
Date: October 29, 2007
Creator: Hawkins, S; Eliel Villa-Aleman, E; Martine Duff, M & Douglas02 Hunter, D
Partner: UNT Libraries Government Documents Department
open access

Solar Resource and Meteorological Assessment Project (SOLRMAP)

Description: The purpose of this collaborative project between NREL and industry is: (1) provide high quality solar measurements in support of deploying Concentrating Solar Thermal projects; and (2) provide NREL with research-quality data sets for refining solar models and developing solar forecasting capabilities. The benefits of this project are: (1) lends NREL credibility to data sets used for economic analyses and commercial justification; (2) helps minimize costly mistakes in estimating capacity and ec… more
Date: October 29, 2008
Creator: Wilcox, S.
Partner: UNT Libraries Government Documents Department
open access

OPTIMIZING RADIOLOGICAL MONITOR SITING OVER THE CONTINENTAL U.S.

Description: The US Environmental Protection Agency (EPA) is installing a network of sensors in the US to monitor background radiation and elevated radiation levels expected from a possible nuclear incident. The network (RadNet) of 180 fixed sensors is intended to provide a basic estimate of the radiation level throughout the US and enhanced accuracy near population centers. This report discusses one of the objective methods for locating these monitors based on criteria outlined by the EPA. The analysis emp… more
Date: October 29, 2007
Creator: Chen, K; Robert Buckley, R; Robert Kurzeja, R; Lance Osteen, L & Saleem Salaymeh, S
Partner: UNT Libraries Government Documents Department
open access

THE NEED FOR A NEW JOINING TECHNOLOGY FOR THE CLOSURE WELDING OF RADIOACTIVE MATERIALS CONTAINERS

Description: One of the activities associated with cleanup throughout the Department of Energy (DOE) complex is packaging radioactive materials into storage containers. Much of this work will be performed in high-radiation environments requiring fully remote operations, for which existing, proven systems do not currently exist. These conditions demand a process that is capable of producing acceptable (defect-free) welds on a consistent basis; the need to perform weld repair, under fully-remote operations, c… more
Date: October 29, 2008
Creator: GR, CANNELL; BE, HILL & GJ, GRANT
Partner: UNT Libraries Government Documents Department
open access

Environmental impacts of the release of a transuranic actinide, americium-241, from a contaminated facility

Description: Americium-241 is widely used as a radiation source, but it also has some potential risk if taken into the body because of its high dose conversion factor. Although the radiotoxicity of americium-241 is small compared to other transuranic actinides, its effects on the reproductive system and on development of the placenta are more damaging than the effects of plutonium-239. In Ohio, a gemologist's laboratory was contaminated with americium-241. Prior to decontamination of the laboratory, potenti… more
Date: October 29, 1985
Creator: Want, J. & Merry-Libby, P.
Partner: UNT Libraries Government Documents Department
open access

Polyurethane foam cable bundle block

Description: Blocking the flow of radioactive gas in the emplacement hole requires attention to three items: stemming materials, cables, and spaces between the cables. This paper deals with an improvement in the latter; that is, filling the spaces between the cables and, thus, forming a bundle block. We have tested a two-part polyurethane foam in the field with apparent success. Field tests included recovery of sample cable bundles from a nuclear test in a tunnel. The foam creates a bundle block that surviv… more
Date: October 29, 1993
Creator: Mercier, J. A.; Cornell, R. H.; Pratuch, S. M. & Lundberg, A.
Partner: UNT Libraries Government Documents Department
open access

Timing is Everything:The Boon and Bane of 14C Geochronology

Description: There are underappreciated limitations of the conversion of {sup 14}C-ages to the fixed, calendrical time-scale that bear directly upon our understanding of the dynamic climate system, or the relationship between the collapse of one civilization and it's neighbor's. In this paper we present a quantitative assessment of the limits of {sup 14}C-geochronology and calibration onto the absolute calendrical time-scale over the Holocene. We take into account not only the inherent limitations of the {s… more
Date: October 29, 2004
Creator: Guilderson, T; Guilderson, T; Reimer, P J & Brown, T
Partner: UNT Libraries Government Documents Department
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