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NSTX Report on FES Joint Facilities Research Milestone 2010

Description: Annual Target: Conduct experiments on major fusion facilities to improve understanding of the heat transport in the tokamak scrape-off layer (SOL) plasma, strengthening the basis for projecting divertor conditions in ITER. The divertor heat flux profiles and plasma characteristics in the tokamak scrape-off layer will be measured in multiple devices to investigate the underlying thermal transport processes. The unique characteristics of C-Mod, DIII-D, and NSTX will enable collection of data over a broad range of SOL and divertor parameters (e.g., collisionality ν*, beta β, parallel heat flux q||, and divertor geometry). Coordinated experiments using common analysis methods will generate a data set that will be compared with theory and simulation.
Date: March 24, 2011
Creator: Maingi, R.; Ahn, J.-W.; Gray, T. K.; McLean, A. G. & Soukhanovskii, V. A.
Partner: UNT Libraries Government Documents Department

Experimental Evaluation of Multi-spacecraft Data Analysis Techniques in a Laboratory Plasma

Description: The Magnetic Reconnection Experiment (MRX)[1] has been utilized to assess the effectiveness of minimum variance analysis on the magnetic field (MVAB) and boundary-crossing time analysis (BCTA). The neutral sheet is swept, or jogged, in a controlled manner with respect to the stationary probes by pulsed internal coil currents. Magnetic field data from measurement points resembling data from multi-spacecraft flying though a reconnecting current sheet is used to check both techniques to deduce a proper normal vector. We examine discharges with the two-dimensional (2-D) X-line structure as well as cases in which a flux rope forms within the layer. All discharges are in a two-fluid regime in which electrons are magnetized but not ions. Boundary-crossing time analysis with four sample measurement points forming a tetrahedron generates a reasonable unit normal vector and relative velocity along the normal vector for all of the tested cases. On the other hand, MVAB sometimes fails to predict a proper normal direction. This is because the X-line magnetic geometry is fundamentally 2-D or 3-D. However, the direction along the reconnecting field determined by MVAB does not deviate much from the real magnetic geometry documented by 2-D magnetic probe arrays and one additional probe at a different toroidal location. Based on these observations, we suggest a procedure for determining a local coordinate system for data from the Magnetospheric Multi-Scale (MMS) mission when spacecraft passes through a reconnecting current sheet. The distance between measurement points on the order of the ion skin depth (c/{omega}{sub pi}) is pertinent to determination of the magnetic geometry.
Date: March 27, 2012
Creator: Yamada, Jongsoo Yoo and Masaaki
Partner: UNT Libraries Government Documents Department

PLUTONIUM FINISHING PLANT (PFP) GENERALIZED GEOMETRY HOLDUP CALCULATIONS & TOTAL MEASUREMENT UNCERTAINTY

Description: A collimated portable gamma-ray detector will be used to quantify the plutonium content of items that can be approximated as a point, line, or area geometry with respect to the detector. These items can include ducts, piping, glove boxes, isolated equipment inside of gloveboxes, and HEPA filters. The Generalized Geometry Holdup (GGH) model is used for the reduction of counting data. This document specifies the calculations to reduce counting data into contained plutonium and the associated total measurement uncertainty.
Date: February 1, 2005
Creator: BD, KEELE
Partner: UNT Libraries Government Documents Department

What product might a renewal of Heavy IonFusion development offerthat competes with methane microbes and hydrogen HTGRs

Description: In 1994 a Fusion Technology journal publication by Logan, Moir and Hoffman described how exploiting unusually-strong economy-of-scale for large (8 GWe-scale) multi-unit HIF plants sharing a driver and target factory among several low cost molten salt fusion chambers {at} < $40M per 2.4 GW fusion each (Fig. 1), could produce electricity below 3 cts/kWehr, even lower than similar multi-unit fission plants. The fusion electric plant could cost $12.5 B for 7.5 GWe and produce hydrogen fuel by electrolysis at prices competitive with gasoline-powered hybrids getting fuel from oil at $20$/bbl. At $60/bbl oil, the fusion plant can cost $35B and compete {at} 10% APR financing. Given massive and still-increasing world demand for transportation fuel even with oil climbing above $60/bbl, large HIF plants producing both low cost electricity and hydrogen could be more relevant to motivate new R&D funding for HIF development in the next few years. Three major challenges to get there: (1) NIF ignition in indirect drive geometry for liquid chambers, (2) a modular accelerator to enable a one-module IRE < $100 M, (3) compatible HIF target, driver and chamber allowing a small driver {at}< $500 M cost for a >100MWe net power DEMO. This scoping study, at a very preliminary conceptual level, attempts to identify how we might meet the last two great challenges taking advantage of several recent ideas and advances which motivate reconsideration of modular HIF drivers: >60X longitudinal compression of neutralized ion beams using a variable waveform induction module in NDCX down to 2 nanosecond bunches, the proof-of-principle demonstration of fast optical-gated solid state SiC switches by George Caporaso's group at LLNL (see George's RPIA06 paper), and recent work by Ed Lee, John Barnard and Hong Qin on methods for time-dependent correction of chromatic focusing errors in neutralized beams with up to 10 % ...
Date: April 19, 2006
Creator: Logan, Grant; Lee, Ed; Yu, Simon; Briggs, Dick; Barnard, John; Friedman, Alex et al.
Partner: UNT Libraries Government Documents Department

COUNTERCURRENT FLOW LIMITATION EXPERIMENTS AND MODELING FOR IMPROVED REACTOR SAFETY

Description: This project is investigating countercurrent flow and “flooding” phenomena in light water reactor systems to improve reactor safety of current and future reactors. To better understand the occurrence of flooding in the surge line geometry of a PWR, two experimental programs were performed. In the first, a test facility with an acrylic test section provided visual data on flooding for air-water systems in large diameter tubes. This test section also allowed for development of techniques to form an annular liquid film along the inner surface of the “surge line” and other techniques which would be difficult to verify in an opaque test section. Based on experiences in the air-water testing and the improved understanding of flooding phenomena, two series of tests were conducted in a large-diameter, stainless steel test section. Air-water test results and steam-water test results were directly compared to note the effect of condensation. Results indicate that, as for smaller diameter tubes, the flooding phenomena is predominantly driven by the hydrodynamics. Tests with the test sections inclined were attempted but the annular film was easily disrupted. A theoretical model for steam venting from inclined tubes is proposed herein and validated against air-water data. Empirical correlations were proposed for air-water and steam-water data. Methods for developing analytical models of the air-water and steam-water systems are discussed, as is the applicability of the current data to the surge line conditions. This report documents the project results from July 1, 2005 through June 30, 2008.
Date: September 26, 2008
Creator: Vierow, Karen
Partner: UNT Libraries Government Documents Department

Survey of the ATLAS Pixel Detector Components

Description: This document provides a description of the survey performed on different componentsof the ATLAS Pixel Detector at different stages of its assembly.
Date: March 19, 2008
Creator: ATLAS; Andreazza, A.; Kostyukhim, V. & Madaras, R.
Partner: UNT Libraries Government Documents Department

Pumpernickel Valley Geothermal Project Thermal Gradient Wells

Description: The Pumpernickel Valley geothermal project area is located near the eastern edge of the Sonoma Range and is positioned within the structurally complex Winnemucca fold and thrust belt of north-central Nevada. A series of approximately north-northeast-striking faults related to the Basin and Range tectonics are superimposed on the earlier structures within the project area, and are responsible for the final overall geometry and distribution of the pre-existing structural features on the property. Two of these faults, the Pumpernickel Valley fault and Edna Mountain fault, are range-bounding and display numerous characteristics typical of strike-slip fault systems. These characteristics, when combined with geophysical data from Shore (2005), indicate the presence of a pull-apart basin, formed within the releasing bend of the Pumpernickel Valley – Edna Mountain fault system. A substantial body of evidence exists, in the form of available geothermal, geological and geophysical information, to suggest that the property and the pull-apart basin host a structurally controlled, extensive geothermal field. The most evident manifestations of the geothermal activity in the valley are two areas with hot springs, seepages, and wet ground/vegetation anomalies near the Pumpernickel Valley fault, which indicate that the fault focuses the fluid up-flow. There has not been any geothermal production from the Pumpernickel Valley area, but it was the focus of a limited exploration effort by Magma Power Company. In 1974, the company drilled one exploration/temperature gradient borehole east of the Pumpernickel Valley fault and recorded a thermal gradient of 160oC/km. The 1982 temperature data from five unrelated mineral exploration holes to the north of the Magma well indicated geothermal gradients in a range from 66 to 249oC/km for wells west of the fault, and ~283oC/km in a well next to the fault. In 2005, Nevada Geothermal Power Company drilled four geothermal gradient wells, PVTG-1, -2, -3, and -4, ...
Date: January 1, 2006
Creator: Szybinski, Z. Adam
Partner: UNT Libraries Government Documents Department

A LIQUID XENON RADIOISOTOPE CAMERA

Description: The increasing availability of short lived gamma and positron emitting isotopes, coupled with the importance of dynamical studies and better imaging, has generated the need for an improved {gamma}-ray camera. The authors discuss a new type of {gamma}-ray camera which makes use of electron avalanches in liquid xenon. A configuration currently under development is shown in Figure 1. The successful operation of a liquid xenon proportional counter was recently reported. The liquid xenon camera promises better spatial resolution and higher counting rate than the existing NaI(Tl) scintillation camera. The spatial resolution for {gamma} rays is in principle limited only by the range of photoelectrons in liquid xenon, which is < 0.2 mm for energies < 1 MeV. A counting rate of 10{sup 6} C/s or more appears possible. As a result of the better resolution and high counting rate capability, the definition of the picture is improved. In addition, the high counting rate capability makes possible dynamic studies which were previously unfeasible. Although they expect the energy resolution with liquid xenon to be superior to that of NaI, the preliminary measurements show 17% FWHM for 279 keV {gamma}'s. Improvements are expected by using better geometry and smoother wire.
Date: February 1, 1972
Creator: Zaklad, Haim.; Derenzo, Stephen E.; Muller, Richard A.; Smadja,Gerard.; Smits, Robert G. & Alvarez, Luis W.
Partner: UNT Libraries Government Documents Department

Electrical Design of Electrostatic Deflectors for Sector-FocusedCyclotrons

Description: The new sector-focused cyclotrons have more energetic and better focused beams at the extraction radius than do ordinary cyclotrons. While the first characteristic requires a more intense electric field, the second permits this field to extend over a smaller volume. By tailoring the electrode geometry to these characteristics of the beam, the required deflector gap and electrode surface become smaller, and a higher gradient can be held without sparking. A different compromise between radioactivity, power dissipation, and resistance to spark damage must be made in selecting electrode materials. Carefully designed electrostatic deflectors perform very well in sector-focused cyclotrons of intermediate energy. Deflector efficiencies of about 50% and external-beam intensities of 20 {micro}A have been obtained in the Lawrence Laboratory's 88 -Inch Cyclotron.
Date: March 25, 1963
Creator: Smith, Bob H. & Grunder, Hermann A.
Partner: UNT Libraries Government Documents Department

Voro++: a three-dimensional Voronoi cell library in C++

Description: Voro++ is a free software library for the computation of three dimensional Voronoi cells. It is primarily designed for applications in physics and materials science, where the Voronoi tessellation can be a useful tool in the analysis of densely-packed particle systems, such as granular materials or glasses. The software comprises of several C++ classes that can be modified and incorporated into other programs. A command-line utility is also provided that can use most features of the code. Voro++ makes use of a direct cell-by-cell construction, which is particularly suited to handling special boundary conditions and walls. It employs algorithms which are tolerant for numerical precision errors, and it has been successfully employed on very large particle systems.
Date: January 15, 2009
Creator: Rycroft, Chris
Partner: UNT Libraries Government Documents Department

BENCHMARKING ORTEC ISOTOPIC MEASUREMENTS AND CALCULATIONS

Description: This report represents a description of compiled benchmark tests conducted to probe and to demonstrate the extensive utility of the Ortec ISOTOPIC {gamma}-ray analysis computer program. The ISOTOPIC program performs analyses of {gamma}-ray spectra applied to specific acquisition configurations in order to apply finite-geometry correction factors and sample-matrix-container photon absorption correction factors. The analysis program provides an extensive set of preset acquisition configurations to which the user can add relevant parameters in order to build the geometry and absorption correction factors that the program determines from calculus and from nuclear g-ray absorption and scatter data. The Analytical Development Section field nuclear measurement group of the Savannah River National Laboratory uses the Ortec ISOTOPIC analysis program extensively for analyses of solid waste and process holdup applied to passive {gamma}-ray acquisitions. Frequently the results of these {gamma}-ray acquisitions and analyses are to determine compliance with facility criticality safety guidelines. Another use of results is to designate 55-gallon drum solid waste as qualified TRU waste3 or as low-level waste. Other examples of the application of the ISOTOPIC analysis technique to passive {gamma}-ray acquisitions include analyses of standard waste box items and unique solid waste configurations. In many passive {gamma}-ray acquisition circumstances the container and sample have sufficient density that the calculated energy-dependent transmission correction factors have intrinsic uncertainties in the range 15%-100%. This is frequently the case when assaying 55-gallon drums of solid waste with masses of up to 400 kg and when assaying solid waste in extensive unique containers. Often an accurate assay of the transuranic content of these containers is not required, but rather a good defensible designation as >100 nCi/g (TRU waste) or <100 nCi/g (low level solid waste) is required. In these cases the ISOTOPIC analysis program is especially valuable because it allows a rapid, defensible, reproducible analysis of ...
Date: September 29, 2008
Creator: Dewberry, R; Raymond Sigg, R; Vito Casella, V & Nitin Bhatt, N
Partner: UNT Libraries Government Documents Department

INTEGRATED HYDROGEN STORAGE SYSTEM MODEL

Description: Hydrogen storage is recognized as a key technical hurdle that must be overcome for the realization of hydrogen powered vehicles. Metal hydrides and their doped variants have shown great promise as a storage material and significant advances have been made with this technology. In any practical storage system the rate of H2 uptake will be governed by all processes that affect the rate of mass transport through the bed and into the particles. These coupled processes include heat and mass transfer as well as chemical kinetics and equilibrium. However, with few exceptions, studies of metal hydrides have focused primarily on fundamental properties associated with hydrogen storage capacity and kinetics. A full understanding of the complex interplay of physical processes that occur during the charging and discharging of a practical storage system requires models that integrate the salient phenomena. For example, in the case of sodium alanate, the size of NaAlH4 crystals is on the order of 300nm and the size of polycrystalline particles may be approximately 10 times larger ({approx}3,000nm). For the bed volume to be as small as possible, it is necessary to densely pack the hydride particles. Even so, in packed beds composed of NaAlH{sub 4} particles alone, it has been observed that the void fraction is still approximately 50-60%. Because of the large void fraction and particle to particle thermal contact resistance, the thermal conductivity of the hydride is very low, on the order of 0.2 W/m-{sup o}C, Gross, Majzoub, Thomas and Sandrock [2002]. The chemical reaction for hydrogen loading is exothermic. Based on the data in Gross [2003], on the order of 10{sup 8}J of heat of is released for the uptake of 5 kg of H{sub 2}2 and complete conversion of NaH to NaAlH{sub 4}. Since the hydride reaction transitions from hydrogen loading to discharge ...
Date: November 16, 2007
Creator: Hardy, B
Partner: UNT Libraries Government Documents Department

TRADITIONAL AND DIGITAL AUTORADIOGRAPHY TECHNIQUES: A COMPARISON STUDY

Description: This report fulfills the FY 2006 Enhanced Surveillance Campaign Level 3 milestones for Task TSR 11.1 as defined in the execution plan [1, 2]. The purpose of this task is to reduce the cycle time necessary to complete analytical evaluations required for surveillance of reservoirs. The development of the digital autoradiography system supports this task. The digital autoradiography system is currently operational and ready for implementation in reservoir surveillance performed in the Materials Test Facility (MTF) at Savannah River Site (SRS). SRS requests design agency (Los Alamos National Laboratory and Sandia National Laboratory) concurrence for the implementation of this system and on the establishment, in conjunction with the Savannah River National Laboratory (SRNL), of the implementation requirements for this system. Stainless steel tritium reservoirs and pinch welded tubes, which have been exposed to tritium for a prolonged period, are destructively evaluated at the end of their service lives for a variety of reasons. One requirement of this evaluation is to assess the tritium diffusion into the reservoir material. The current method used to determine the geometry and depth of tritium penetration is autoradiography. This technique employs a photographic emulsion and has been effective for a number of years. The primary disadvantage of this technique is the time required to obtain results. The success of the traditional technique is dependent on many variables, such as the proficiency of the operators in conducting sample preparation, the geometry of the sample and the shelf life of the photographic chemicals. If results are not satisfactory, several repetitions are often required and usually add weeks to the total analysis time for the sample. Due to the extensive time required for the liquid emulsion autoradiography method, a new, faster technique was desired. Personnel from the Savannah River National Laboratory (SRNL) have been working on a system ...
Date: August 29, 2006
Creator: Gibbs, K & Carol Kestin, C
Partner: UNT Libraries Government Documents Department

Antiproton Interaction Cross Sections

Description: Using the 1.19-Bev/c antiproton beam recently discovered at the Berkeley Bevatron of the University of California, we have measured the attenuation cross section in beryllium and copper. These cross sections are compared to attenuation measurements made with the same geometry using positive protons of the same incident energy (497 MeV).
Date: February 27, 1956
Creator: Chamberlain, Owen; Keller, Donald V.; Segre, Emilio; Steiner,Herbert M.; Wiegand, Clyde & Ypsilantis, Tom
Partner: UNT Libraries Government Documents Department

Feedthrough Signal Board to Cryostat Seal Design, Testing

Description: The D0 LAr calorimeters are contained in three cylindrical cryostats, symmetrical about the X-Y plain drawn perpendicular to the beam (Z) and through the middle of the center calot:imeter (CC), and terminating in a north and south end calorimeters (ECN, ECS). The center calorimeter holds ca. 5,000, and each end calorimeters holds 3,000, gallons of LAr (BP= ca. 90K) at a nominal pressure of 4/3 atm. The 96 (32 per cryostat) multilayer, G10, signal boards map the signals from the detector to the preamplifiers, while 'feeding them through' the boundary wall between the argon cryostat and the atmosphere. The feedthrough function is accomplished by attaching a hermetic flange to the signal board, and then sealing the flange to an opening in a stainless steel 'signal box', an extension of the cryostat, with a bolted sea. The geometry is arranged to stratify the gas temperature in a 'tower' (port) to keep the box assemblies, nominally, at room temperature. The cryostat design must obey a set of physical constraints that, effectively, require that the circular cross-section be inscribed in a square. All warm 'access ports' are constrained to reside in the upper quadrants; defined as above the equator, outside the circular cross-section, and inside the square. The small diameter (8-inch, 6-inch pipe), vertical axis, ports penetrate the cylindrical, horizontal axis, cryostat shells at large (ca. 45 degree) azimuthal angles to allow a 'reasonable', vertical, heat leak path for the seven (one instrumentation, two HV, four signal) ports required. Each of these ports is 'closed' by a box that serves to provide a surface for the 'feedthroughs', an access panel or panels, and is itself sealed to a cryostat flange. There as many box seals as boxes (seven), eleven panel seals, and (32+80+15) = 127 feedthrough assemblies providing (32*(1200) + 80(8) + 15(61)) ...
Date: April 1, 1990
Creator: Applegate, D.; Mulholland, G.T.; Trotter, G. & /Fermilab
Partner: UNT Libraries Government Documents Department

Finite Element Analysis of EC Insert Plug

Description: The proposed EC calorimeter insert plug was modeled with ANSYS to verify that the shell thickness calculated with beam formulas are adequate. The finite element model and dimensions is shown in Fig. 1. The geometry and shell thicknesses used were the best numbers available as of 3/28/86. The model includes only the inner and outer shells and intermediate structural discs. The total weight of the plug is calculated to be 75000 lbs. The plug is supported against this weight at the four nodes indicated in Fig. 1. A vertical constraint was used. The calorimeter plates are not explicitly modeled. Their weight is placed on the inner shell by giving the shell material an appropriate density and applying a global acceleration. In addition to the weight loading, there will also be a pressure loading applied to both end plates as a result of preloading the calorimeter plates compressively. This pressure is estimated to be 20 pSi, and was represented in the model as a uniform pressure applied across each end plate. The large axial force produced by this pressure precludes the possibility of attaching the inner shell to both end plates. Such attachments would be under unreasonably high stress as the plates were preloaded, and the inner shell would be under a state of tension in trying to resist the axial force. In the real structure, the inner shell will be attached to at most one of the end plates. The axial force is then developed solely in the outer shell, which has a considerable area of attachment. To emulate this in the finite model, nodal coupling was used to couple the shell laterally to both end plates and all intermediate discs to ensure weight transfer, but axially the shell was only coupled to one of the end plates. The materials ...
Date: April 1, 1986
Creator: Wands, R.
Partner: UNT Libraries Government Documents Department

Effects of liquid helium bubble formation in a superconducting cavity cryogenic system

Description: We constructed a simple prototype model based on the geometry of the 56 MHz superconducting cavity for RHIC. We studied the formation, in this prototype, of bubbles of liquid helium and their thermal effects on the cavity. We found that due to the low viscosity of the liquid helium, and its small surface tension, no large bubbles formed. The tiny bubbles, generated from most of the area, behaved like light gas travelling in a free space and escaped from the trapping region. The bubbles that were generated in the trapping area, due to its descending geometry, are much bigger than the other bubbles, but due to the liquid flow generated by heating, they still are negligible compared to the size of the trapping region. We expected that the effects of bubbles in our 56 MHz cavity during operation might well be negligible.
Date: March 1, 2011
Creator: Chang, X.; Wang, E. & Xin, T.
Partner: UNT Libraries Government Documents Department

The effects of realistic pancake solenoids on particle transport

Description: Solenoids are widely used to transport or focus particle beams. Usually, they are assumed as being ideal solenoids with a high axial-symmetry magnetic field. Using the Vector Field Opera program, we modeled asymmetrical solenoids with realistic geometry defects, caused by finite conductor and current jumpers. Their multipole magnetic components were analyzed with the Fourier fit method; we present some possible optimized methods for them. We also discuss the effects of 'realistic' solenoids on low energy particle transport. The finding in this paper may be applicable to some lower energy particle transport system design.
Date: February 1, 2011
Creator: Gu, X.; Okamura, M.; Pikin, A.; Fischer, W. & Luo, Y.
Partner: UNT Libraries Government Documents Department

Measurement of groove features and dimensions of the vertical test cathode and the choke joint of the superconducting electron gun cavity of the Energy Recovery LINAC

Description: A testing program for the superconducting electron gun cavity that has been designed for the Energy Recovery LINAC is being planned. The goal of the testing program is to characterize the RF properties of the gun cavity at superconducting temperatures and, in particular, to study multipacting that is suspected to be occurring in the choke joint of the cavity where the vertical test cathode is inserted. The testing program will seek to understand the nature and cause of this multipacting and attempt to eliminate it, if possible, by supplying sufficient voltage to the cavity. These efforts are motivated by the multipacting issues that have been observed in the processing of the fine-grain niobium gun cavity. This cavity, which is being processed at Thomas Jefferson National Laboratory for Brookhaven, has encountered multipacting at a gradient of approximately 3 MV/m and, to date, has resisted efforts at elimination. Because of this problem, a testing program is being established here in C-AD that will use the large-grain niobium gun cavity that currently resides at Brookhaven and has been used for room-temperature measurements. The large-grain and fine-cavities are identical in every aspect of construction and only differ in niobium grain size. Thus, it is believed that testing and conditioning of the large-grain cavity should yield important insights about the fine-grain cavity. One element of this testing program involves characterizing the physical features of the choke joint of the cavity where the multipacting is believed to be occurring and, in particular the grooves of the joint. The configuration of the cavity and the vertical test cathode is shown in Figure 1. In addition, it is important to characterize the groove of the vertical test cathode. The grooved nature of these two components was specifically designed to prevent multipacting. However, it is suspected that, because of ...
Date: October 13, 2011
Creator: Hammons, L. & Ke, M.
Partner: UNT Libraries Government Documents Department

A Special Purpose Slide Rule for Computing Solid Angles

Description: Abstract: The design and construction of a slide rule for calculating the solid angle subtended by a rectangle at a point located on a line perpendicular to the center of the rectangle are described.
Date: September 19, 1957
Creator: Knight, J. R. & Henry, H. F.
Partner: UNT Libraries Government Documents Department

Perrhenate and Pertechnetate Behavior on Iron and Sulfur-Bearing Compounds.

Description: Investigations on the behavior of the radioactive element technetium frequently use a stable isotope of rhenium as an analogue. This is justified by citing the elements similar radii and major oxidation states of +7 and +4. However, at least one study [1] has shown this analogy to be imperfect. Therefore, one goal of our study is to compare the adsorption behavior of perrhenate and pertechnetate (the major forms of Re and Tc in natural waters) on a number of different mineral surfaces. Quantum mechanical calculations were performed on the adsorption of these two anions on a series of iron oxides and sulfides. With these calculations, we gain insight into any differences between the anions adsorption behavior, including geometry, adsorption energies, and electronic structure such as density of states and orbital shapes and energies at the adsorption site. Differences between interactions on terraces and step edges, the effects of co-adsorbates such as Na{sup +} or H{sup +}, and possible reduction mechanisms are also explored. The influence of water was calculated using homogeneous dielectric fluids and explicit water molecules. As a complement to the calculations, batch sorption tests are in progress involving ReO{sub 4}{sup -}/TcO{sub 4}{sup -} solution in contact with Fe metal, 10% Fe-doped hydroxyapatite, goethite, hematite, magnetite, pyrite, galena, and sphalerite.
Date: September 15, 2006
Creator: Anderson, B. E.; Becker, U.; Helean, K. B. & Ewing, R. C.
Partner: UNT Libraries Government Documents Department

Vacuum Systems Consensus Guideline for Department of Energy Accelerator Laboratories

Description: Vacuum vessels, including evacuated chambers and insulated jacketed dewars, can pose a potential hazard to equipment and personnel from collapse, rupture due to back-fill pressurization, or implosion due to vacuum window failure. It is therefore important to design and operate vacuum systems in accordance with applicable and sound engineering principles. 10 CFR 851 defines requirements for pressure systems that also apply to vacuum vessels subject to back-fill pressurization. Such vacuum vessels are potentially subject to the requirements of the American Society of Mechanical Engineers (ASME) Pressure Vessel Code Section VIII (hereafter referred to as the 'Code'). However, the scope of the Code excludes vessels with internal or external operating pressure that do not exceed 15 pounds per square inch gauge (psig). Therefore, the requirements of the Code do not apply to vacuum systems provided that adequate pressure relief assures that the maximum internal pressure within the vacuum vessel is limited to less than 15 psig from all credible pressure sources, including failure scenarios. Vacuum vessels that cannot be protected from pressurization exceeding 15 psig are subject to the requirements of the Code. 10 CFR 851, Appendix A, Part 4, Pressure Safety, Section C addresses vacuum system requirements for such cases as follows: (c) When national consensus codes are not applicable (because of pressure range, vessel geometry, use of special materials, etc.), contractors must implement measures to provide equivalent protection and ensure a level of safety greater than or equal to the level of protection afforded by the ASME or applicable state or local code. Measures must include the following: (1) Design drawings, sketches, and calculations must be reviewed and approved by a qualified independent design professional (i.e., professional engineer). Documented organizational peer review is acceptable. (2) Qualified personnel must be used to perform examinations and inspections of materials, in-process fabrications, ...
Date: September 9, 2008
Creator: Casey,R.; Haas, E.; Hseuh, H-C.; Kane, S.; Lessard, E.; Sharma, S. et al.
Partner: UNT Libraries Government Documents Department

Low Speed Technology for Small Turbine Development Reaction Injection Molded 7.5 Meter Wind Turbine Blade

Description: An optimized small turbine blade (7.5m radius) was designed and a partial section molded with the RIM (reaction-injection molded polymer) process for mass production. The intended market is for generic three-bladed wind turbines, 100 kilowatts or less, for grid-assist end users with rural and semi-rural sites, such as the farm/ranch market, having low to moderate IEC Class 3-4 wind regimes. This blade will have substantial performance improvements over, and be cheaper than, present-day 7.5m blades. This is made possible by the injection-molding process, which yields high repeatability, accurate geometry and weights, and low cost in production quantities. No wind turbine blade in the 7.5m or greater size has used this process. The blade design chosen uses a RIM skin bonded to a braided infused carbon fiber/epoxy spar. This approach is attractive to present users of wind turbine blades in the 5-10m sizes. These include rebladeing California wind farms, refurbishing used turbines for the Midwest farm market, and other manufacturers introducing new turbines in this size range.
Date: July 31, 2007
Creator: Wright, David M. & Bennett, DOE Project Officer - Keith
Partner: UNT Libraries Government Documents Department