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Modeling Free Convection Flow of Liquid Hydrogen within a Cylindrical Heat Exchanger Cooled to 14 K

Description: A liquid hydrogen in a absorber for muon cooling requires that up to 300 W be removed from 20 liters of liquid hydrogen. The wall of the container is a heat exchanger between the hydrogen and 14 K helium gas in channels within the wall. The warm liquid hydrogen is circulated down the cylindrical walls of the absorber by free convection. The flow of the hydrogen is studied using FEA methods for two cases and the heat transfer coefficient to the wall is calculated. The first case is when the wall… more
Date: May 8, 2004
Creator: Green, Michael A.; Yang, S. W.; Green, M. A. & Lau, W.
Partner: UNT Libraries Government Documents Department
open access

Developing a next-generation community college curriculum forenergy-efficient high-performance building operations

Description: The challenges of increased technological demands in today's workplace require virtually all workers to develop higher-order cognitive skills including problem solving and systems thinking in order to be productive. Such ''habits of mind'' are viewed as particularly critical for success in the information-based workplace, which values reduced hierarchy, greater worker independence, teamwork, communications skills, non-routine problem solving, and understanding of complex systems. The need is pa… more
Date: May 1, 2004
Creator: Crabtree, Peter; Kyriakopedi, Nick; Mills, Evan; Haves, Philip; Otto, Roland J.; Piette, Mary Ann et al.
Partner: UNT Libraries Government Documents Department
open access

'Shim pulses' for NMR spectroscopy in inhomogeneous magneticfields

Description: NMR spectroscopy conveys information about chemical structure through ppm-scale shifts of the resonance frequency depending on the chemical environment. In order to observe these small shifts, magnets with highly homogeneous magnetic field B{sub 0} are used. The high cost and large size of these magnets are a consequence of the requirement for high homogeneity. In this contribution we introduce a new method for recording high-resolution NMR spectra from samples in inhomogeneous B{sub 0}, openin… more
Date: May 19, 2004
Creator: Topgaard, Daniel; Martin, Rachel W.; Sakellariou, Dimitris; Meriles, Carlos & Pines, Alexander
Partner: UNT Libraries Government Documents Department
open access

Clothes washer standards in China -- The problem of water andenergy trade-offs in establishing efficiency standards

Description: Currently the sales of clothes washers in China consist ofseveral general varieties. Some use more energy (with or withoutincluding hot water energy use) and some use more water. Both energy andwater are in short supply in China. This poses the question - how do youtrade off water versus energy in establishing efficiency standards? Thispaper discusses how China dealt with this situation and how itestablished minimum efficiency standards for clothes washers.
Date: May 19, 2004
Creator: Biermayer, Peter J. & Lin, Jiang
Partner: UNT Libraries Government Documents Department
open access

Theoretical study of the electronic states of Nb4, Nb5 clusters and their anions (Nb4?, Nb5?)

Description: Geometries and energy separations of the various low-lying electronic states of Nb{sub n} and Nb{sub n}{sup -} (n = 4, 5) clusters with various structural arrangements have been investigated. The complete active space multi-configuration self-consistent field (CASMCSCF) method followed by multi-reference singles and doubles configuration interaction (MRSDCI) calculations that included up to 52 million configuration spin functions have been used to compute several electronic states of these clus… more
Date: May 6, 2004
Creator: Balasubramanian, K & Majumdar, D
Partner: UNT Libraries Government Documents Department
open access

DESIGN, CONSTRUCTION, AND STATUS OF ALL NIOBIUM SUPERCONDUCTING PHOTOINJECTOR AT BNL.

Description: We present here the design and construction of an all niobium superconducting RF injector to generate high average current, high brightness electron beam. A 1/2 cell superconducting cavity has been designed, built, and tested. A cryostat has been built to cool the cavity to {approx}2 K. The RF system can deliver up to 500 W at 1.3 GHz to the cavity. A mode-locked Nd:YVO{sub 4} laser, operating at 266 nm with 0.15 W average power, phase locked to the RF, will irradiate a laser cleaned Nb surface… more
Date: May 12, 2004
Creator: SRINIVASAN-RAO,T. BEN-ZVI,I. BURRILL,A. CITVER,G. ET AL.
Partner: UNT Libraries Government Documents Department
open access

Multi-Tube Power Leads Tower for Bepcii Ir Magnets.

Description: A power lead tower containing the multi-tube power leads is designed and under fabrication for the superconducting IR quadrupole magnets in the Beijing Electron Position Collider Upgrade (BEPCII). The lead tower consists of six pairs of gas-cooled leads for seven superconducting coils at various operating currents. The power lead is designed in a modular fashion, which can be easily applied to suit different operating current. The end copper block of the tube lead has a large cold mass that pro… more
Date: May 11, 2004
Creator: Jia, L. X.; Zhang, X. B.; Wang, L.; Wang, T. H. & Yao, Z. L.
Partner: UNT Libraries Government Documents Department
open access

Transforming the Market for Sustainable Design: Effective Public Policies and Strategies; Preprint

Description: The federal government strives to lead by example in energy and resource management and architectural design. This paper explores how public agencies are supporting that goal by using sustainable practices in the design and operation of their buildings. It presents some elements to consider in establishing a policy for sustainable design and a system for implementing that policy, including some of the most difficult implementation issues agencies have to face. The paper also highlights some of … more
Date: May 1, 2004
Creator: Carlisle, N.; Glickman, J.; Brown, M.; Foster, M.; Bennett, A. K. & Sandler, K.
Partner: UNT Libraries Government Documents Department
open access

Intracavity adaptive correction of a 10 kW, solid-state, heat-capacity laser

Description: The Solid-State, Heat-Capacity Laser (SSHCL), under development at Lawrence Livermore National Laboratory (LLNL) is a large aperture (100 cm{sup 2}), confocal, unstable resonator requiring near-diffraction-limited beam quality. There are two primary sources of the aberrations in the system: residual, static aberrations from the fabrication of the optical components and predictable, time-dependent, thermally-induced index gradients within the gain medium. A deformable mirror placed within the ca… more
Date: May 13, 2004
Creator: LaFortune, K N; Hurd, R L; Brase, J M & Yamamoto, R M
Partner: UNT Libraries Government Documents Department
open access

Thermal Fluid Modeling of Bepcii Ir Quadrupole Magnet Cryostat.

Description: A pair of superconducting interaction region quadrupole magnets for BEPCII was designed and fabricated at Brookhaven National Laboratory, USA. The cryogenic system for the IR magnets was designed at Harbin Institute of Technology, China. This paper provides the results of thermal fluid modeling for the magnet cryostat. The numerical analyses were carried out for two types of cooling methods, the subcooled liquid helium and the supercritical helium flow. The pressure and temperature changes in t… more
Date: May 11, 2004
Creator: Wang, L.; Tang, H. M.; Zhang, X. B.; Yang, G. D. & Jia, L. X.
Partner: UNT Libraries Government Documents Department
open access

Comment on ''Sensitivity Analysis and Determination of Streambed Leakance and Aquifer Hydraulic Properties'' by Xunhong Chen and Xi Chen, Journal of Hydrology, 2003, v.284, 270-284

Description: Recently, studies of the Platte River watershed have gained significant attention from federal and Nebraska, USA, state agencies due to the importance of groundwater/surface-water interactions under drought conditions. Using archive data from a 1983 pumping test, Chen and Chen (2003) interpret the hydraulic properties of the alluvium and a streambed of the Platte River near Kearney, Nebraska, and compare their data with results of other studies performed over the past several years. Three impor… more
Date: May 17, 2004
Creator: Kollet, S
Partner: UNT Libraries Government Documents Department
open access

Simulation of Plasma Fluxes to Material Surfaces with Self-Consistent Edge Turbulence and Transport for Tokamaks

Description: The edge-plasma profiles and fluxes to the divertor and walls of a divertor tokamak with a magnetic X-point are simulated by coupling a 2D transport code (UEDGE) and a 3D turbulence code (BOUT). An relaxed iterative coupling scheme is used where each code is run on its characteristic time scale, resulting in a statistical steady state. Plasma variables of density, parallel velocity, and separate ion and electron temperatures are included, together with a fluid neutral model for recycling neutra… more
Date: May 24, 2004
Creator: Rognlien, T.; Umansky, M.; Xu, X.; Cohen, R. & LoDestro, L.
Partner: UNT Libraries Government Documents Department
open access

Properties of RR Lyrae stars in the Inner Regions of the Large Magellanic Cloud

Description: We present the radial velocities, metallicities and the K-band magnitudes of 74 RR Lyrae stars in the inner regions of the LMC. The intermediated resolution spectra and the infrared images were obtained with FORS1 at the ESO VLT and with the SOFI infrared imager at the ESO NTT. The best 43 RR Lyrae with measured velocities yield an observed velocity dispersion of {sigma}=61{+-} 7 km s{sup -1}. We obtain a true LMC RR Lyrae velocity dispersion of {sigma}=53 km s{sup -1}, which is higher than the… more
Date: May 27, 2004
Creator: Borissova, J; Minniti, D; Rejkuba, M; Alves, D; Cook, K H & Freeman, K C
Partner: UNT Libraries Government Documents Department
open access

Deflagration of HMX-Based Explosives at High Temperatures and Pressures

Description: We measure the deflagration behavior of energetic materials at extreme conditions (up to 520K and 1 GPa) in the LLNL High Pressure Strand Burner, thereby obtaining reaction rate data for prediction of violence of thermal explosions. The apparatus provides both temporal pressure history and flame time-of-arrival information during deflagration, allowing direct calculation of deflagration rate as a function of pressure. Samples may be heated before testing. Here we report the deflagration behavio… more
Date: May 12, 2004
Creator: Maienschein, J. L.; Wardell, J. F.; DeHaven, M. R. & Black, C. K.
Partner: UNT Libraries Government Documents Department
open access

Sorption and Transport of Iodine Species in Sediments from the Savannah River and Hanford Sites

Description: Iodine is an important element in studies of environmental protection and human health, global-scale hydrologic processes and nuclear nonproliferation. Biogeochemical cycling of iodine is complex, because iodine occurs in multiple oxidation states and as inorganic and organic species that may be hydrophilic, atmophilic, and biophilic. In this study, we focused on the sorption and transport behavior of iodine species (iodide, iodate, and 4-iodoaniline) in sediments collected at the Savannah Rive… more
Date: May 20, 2004
Creator: Hu, Q; Zhao, P; Moran, J & Seaman, J
Partner: UNT Libraries Government Documents Department
open access

Carbon Nanotube-Based Permeable Membranes: A Platform for Studying Nanofluidics

Description: A membrane of multiwalled carbon nanotubes embedded in a silicon nitride matrix was fabricated for use in studying fluid mechanics on the nanometer scale. Characterization by fluorescent tracer diffusion and scanning electron microscopy suggests that the membrane is void-free near the silicon substrate on which it rests, implying that the hollow core of the nanotube is the only conduction path for molecular transport. Nitrogen flow measurements of a nanoporous silicon nitride membrane, fabricat… more
Date: May 25, 2004
Creator: Holt, J K; Park, H G; Noy, A; Huser, T; Eaglesham, D & Bakajin, O
Partner: UNT Libraries Government Documents Department
open access

Simulation of Chamber Transport for Heavy-Ion Fusion Drivers

Description: The heavy-ion fusion (HIF) community recently developed a power-plant design that meets the various requirements of accelerators, final focus, chamber transport, and targets. The point design is intended to minimize physics risk and is certainly not optimal for the cost of electricity. Recent chamber-transport simulations, however, indicate that changes in the beam ion species, the convergence angle, and the emittance might allow more-economical designs.
Date: May 20, 2004
Creator: Sharp, W. M.; Callahan, D. A.; Tabak, M.; Yu, S. S.; Peterson, P. F.; Rose, D. V. et al.
Partner: UNT Libraries Government Documents Department
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