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Ultimate strength of carbon nanotubes: A theoretical study (open access)

Ultimate strength of carbon nanotubes: A theoretical study

Article on a theoretical study of the ultimate strength of carbon nanotubes.
Date: March 27, 2002
Creator: Zhao, Qingzhong; Buongiorno Nardelli, Marco & Bernholc, Jerry
System: The UNT Digital Library
A Survey of U.S. Olympic Coaches: Variables Perceived to Have Influenced Athlete Performances and Coach Effectiveness (open access)

A Survey of U.S. Olympic Coaches: Variables Perceived to Have Influenced Athlete Performances and Coach Effectiveness

This article discusses research on variables perceived to have influenced athlete performances and coach effectiveness.
Date: 2002
Creator: Gould, Daniel; Guinan, Diane; Greenleaf, Christy & Chung, Yongchul
System: The UNT Digital Library
Virtual Libraries: A Service-Based Approach for Virtual Libraries (open access)

Virtual Libraries: A Service-Based Approach for Virtual Libraries

Article discussing a service-based approach for virtual libraries and the provision of services to patrons and other users built upon the collective personnel, information, and technological resources that constitute the library.
Date: Autumn 2002
Creator: Moen, William E. & Murray, Kathleen R.
System: The UNT Digital Library
Superconducting solenoids for an international muon coolingexperiment (open access)

Superconducting solenoids for an international muon coolingexperiment

None
Date: August 3, 2002
Creator: Green, M.A. & Rey, J.M.
System: The UNT Digital Library
Neutron-induced prompt gamma activation analysis (PGAA) of metalsand non-metals in ocean floor geothermal vent-generated samples (open access)

Neutron-induced prompt gamma activation analysis (PGAA) of metalsand non-metals in ocean floor geothermal vent-generated samples

Neutron-induced prompt gamma activation analysis (PGAA) hasbeen used to analyze ocean floor geothermal vent-generated samples thatare composed of mixed metal sulfides, silicates, and aluminosilicates.The modern application of the PGAA technique is discussed, and elementalanalytical results are given for 25 elements observed in the samples. Theelemental analysis of the samples is consistent with the expectedmineralogical compositions, and very consistent results are obtained forcomparable samples. Special sensitivity to trace quantities of hydrogen,boron, cadmium, dysprosium, gadolinium, and samarium isdiscussed.
Date: December 5, 2002
Creator: Perry, D. L.; Firestone, R. B.; Molnar, G. L.; Revay, Zs.; Kasztovszky, Zs.; Gatti, R. C. et al.
System: The UNT Digital Library
Workshop on ENU Mutagenesis: Planning for Saturation, July 25-28, 2002 (open access)

Workshop on ENU Mutagenesis: Planning for Saturation, July 25-28, 2002

The goal of the conference is to enhance the development of improved technologies and new approaches to the identification of genes underlying chemically-induced mutant phenotypes. The conference brings together ENU mutagenesis experts from the United States and aborad for a small, intensive workshop to consider these issues.
Date: July 25, 2002
Creator: Nadeau, Joseph H
System: The UNT Digital Library
Risk Informing the Nuclear Materials and Waste Arenas. (open access)

Risk Informing the Nuclear Materials and Waste Arenas.

None
Date: November 17, 2002
Creator: Bari, R. A.; Mubayi, V.; Azarm, M. A.; Grove, E. J.; Xu, J.; Bailey, M. G. et al.
System: The UNT Digital Library
Going with the flow: Life cycle costing for industrial pumping systems (open access)

Going with the flow: Life cycle costing for industrial pumping systems

Industries worldwide depend upon pumping systems for theirdaily operation. These systems account for nearly 20 percent of theworld's industrial electrical energy demand and range from 25-50 percentof the energy usage in certain industrial plant operations. Purchasedecisions for a pump and its related system components are typicallybased upon a low bid, rather than the cost to operate the system over itslifetime. Additionally, plant facilities personnel are typically focussedon maintaining existing pumping system reliability rather than optimizingthe systems for best energy efficiency. To ensure the lowest energy andmaintenance costs, equipment life, and other benefits, the systemcomponents must be carefully matched to each other, and remain sothroughout their working lives. Life Cycle Cost (LCC) analysis is a toolthat can help companies minimize costs and maximize energy efficiency formany types of systems, including pumping systems. Increasing industryawareness of the total cost of pumping system ownership through lifecycle cost analysis is a goal of the US Department of Energy (DOE). Thispaper will discuss what DOE and its industry partners are doing to createthis awareness. A guide book, Pump Life Cycle Costs: A Guide to LCCAnalysis for Pumping Systems, developed by the Hydraulic Institute (HI)and Europump (two pump manufacturer trade associations) with DOEinvolvement, will be overviewed. …
Date: July 8, 2002
Creator: Tutterow, Vestal; Hovstadius, Gunnar & McKane, Aimee
System: The UNT Digital Library
Updating the Nrc Guidance for Human Factors Engineering Reviews. (open access)

Updating the Nrc Guidance for Human Factors Engineering Reviews.

None
Date: September 15, 2002
Creator: O Hara, J. M.; Brown, W. S.; Higgins, J. C.; Persensky, J. J.; Lewis, P. M. & Bongarra, J.
System: The UNT Digital Library
A cold mass support system based on the use of oriented fiberglassepoxy rods in bending (open access)

A cold mass support system based on the use of oriented fiberglassepoxy rods in bending

This report describes a cold mass support system based on the use of oriented fiberglassepoxy rods in bending.
Date: July 6, 2002
Creator: Green, Michael A.; Corradi, Carol A.; LaMantia, Roberto F. & Zbasnik, Jon P.
System: The UNT Digital Library
Residential hot water distribution systems: Roundtablesession (open access)

Residential hot water distribution systems: Roundtablesession

Residential building practice currently ignores the lossesof energy and water caused by the poor design of hot water systems. Theselosses include: combustion and standby losses from water heaters, thewaste of water (and energy) while waiting for hot water to get to thepoint of use; the wasted heat as water cools down in the distributionsystem after a draw; heat losses from recirculation systems and thediscarded warmth of waste water as it runs down the drain. Severaltechnologies are available that save energy (and water) by reducing theselosses or by passively recovering heat from wastewater streams and othersources. Energy savings from some individual technologies are reported tobe as much as 30 percent. Savings calculations of prototype systemsincluding bundles of technologies have been reported above 50 percent.This roundtable session will describe the current practices, summarizethe results of past and ongoing studies, discuss ways to think about hotwater system efficiency, and point to areas of future study. We will alsorecommend further steps to reduce unnecessary losses from hot waterdistribution systems.
Date: August 1, 2002
Creator: Lutz, James D.; Klein, Gary; Springer, David & Howard, Bion D.
System: The UNT Digital Library
DFBX boxes -- electrical and cryogenic distribution boxes for thesuperconducting magnets in the LHC straight sections (open access)

DFBX boxes -- electrical and cryogenic distribution boxes for thesuperconducting magnets in the LHC straight sections

None
Date: August 3, 2002
Creator: Zbasnik, Jon P.; Corradi, Carol A.; Gourlay, S.A.; Green, MichaelA.; Hafalia, Aurelio Q.; Kajiyama (Jr.), Yoichi et al.
System: The UNT Digital Library
Energy Efficiency Standards and Labels in North America: Opportunities for Harmonization (open access)

Energy Efficiency Standards and Labels in North America: Opportunities for Harmonization

To support the North American Energy Working Group's Expert Group on Energy Efficiency (NAEWG-EE), USDOE commissioned the Collaborative Labeling and Appliance Standards Program (CLASP) to prepare a resource document comparing current standards, labels, and test procedure regulations in Canada, Mexico, and the United States. The resulting document reached the following conclusions: Out of 24 energy-using products for which at least one of the three countries has energy efficiency regulations, three products -- refrigerators/freezers, split system central air conditioners, and room air conditioners -- have similar or identical minimum energy performance standards (MEPS) in the three countries. These same three products, as well as three-phase motors, have similar or identical test procedures throughout the region. There are 10 products with different MEPS and test procedures, but which have the short-term potential to develop common test procedures, MEPS, and/or labels. Three other noteworthy areas where possible energy efficiency initiatives have potential for harmonization are standby losses, uniform endorsement labels, and a new standard or label on windows. This paper explains these conclusions and presents the underlying comparative data.
Date: May 16, 2002
Creator: Vanwiemcgrory, Laura; Wiel, Stephen; Van Wie McGrory, Laura & Harrington, Lloyd
System: The UNT Digital Library
A Long-Term Comparison of Yellowstone Cutthroat Trout Abundance and Size Structure in Their Historical Range in Idaho. (open access)

A Long-Term Comparison of Yellowstone Cutthroat Trout Abundance and Size Structure in Their Historical Range in Idaho.

We compared estimates of population abundance and size structure for Yellowstone cutthroat trout Oncorhynchus clarki bouvieri obtained by electrofishing 77 stream segments across southeastern Idaho in the 1980s and again in 1999-2000 to test whether populations of Yellowstone cutthroat trout had changed. Sites sampled in the 1980s were relocated in 1999-2000 by using maps and photographs or by finding original site-boundary stakes, so that the same reach of stream was sampled during both periods. Abundance of Yellowstone cutthroat trout longer than 10 cm did not change, averaging 41 fish/100 m of stream during both the 1980s and 1999-2000. The proportion of the total catch of trout composed of Yellowstone cutthroat trout also did not change, averaging 82% in the 1980s and 78% in 1999-2000. At the 48 sites where size structure could be estimated for both periods, the proportion of Yellowstone cutthroat trout that were 10-20 cm long declined slightly (74% versus 66%), but the change was due entirely to the shift in size structure at the Teton River sites. The number of sites that contained rainbow trout O. mykiss or cutthroat trout 3 rainbow trout hybrids rose from 23 to 37, but the average proportion of the catch composed …
Date: May 23, 2002
Creator: Meyer, Kevin A.; Schill, Daniel J. & Elle, F. Steven
System: The UNT Digital Library
Proposed Reference Spectral Irradiance Standards to Improve Photovoltaic Concentrating System Design and Performance Evaluation: Preprint (open access)

Proposed Reference Spectral Irradiance Standards to Improve Photovoltaic Concentrating System Design and Performance Evaluation: Preprint

This conference paper describes the American Society for Testing and Materials (ASTM), the International Electrotechnical Commission (IEC), and the International Standards Organization (ISO) standard solar terrestrial spectra (ASTM G-159, IEC-904-3, ISO 9845-1) provide standard spectra for photovoltaic performance applications. Modern terrestrial spectral radiation models and knowledge of atmospheric physics are applied to develop suggested revisions to update the reference spectra. We use a moderately complex radiative transfer model (SMARTS2) to produce the revised spectra. SMARTS2 has been validated against the complex MODTRAN radiative transfer code and spectral measurements. The model is proposed as an adjunct standard to reproduce the reference spectra. The proposed spectra represent typical clear sky spectral conditions associated with sites representing reasonable photovoltaic energy production and weathering and durability climates. The proposed spectra are under consideration by ASTM.
Date: May 1, 2002
Creator: Myers, D. R.; Emery, K. E. & Gueymard, C.
System: The UNT Digital Library
Field and Current Amplification in the SSPX Spheromak (open access)

Field and Current Amplification in the SSPX Spheromak

Results are presented from experiments relating to magnetic field generation and current amplification in the SSPX spheromak. The SSPX spheromak plasma is driven by DC coaxial helicity injection using a 2MJ capacitor bank. Peak toroidal plasma currents of up to 0.7MA and peak edge poloidal fields of 0.3T are produced; lower current discharges can be sustained up to 3.5msec. When edge magnetic fluctuations are reduced below 1% by driving the plasma near threshold, it is possible to produce plasmas with Te > 150eV, <{beta}{sub e}>-4% and core {chi}{sub e} {approx} 30m{sup 2}/s. Helicity balance for these plasmas suggests that sheath dissipation can be significant, pointing to the importance of maximizing the voltage on the coaxial injector. For most operational modes we find a stiff relationship between peak spheromak field and injector current, and little correlation with plasma temperature, which suggests that other processes than ohmic dissipation may limit field amplification. However, slowing spheromak buildup by limiting the initial current pulse increases the ratio of toroidal current to injected current and points to new operating regimes with more favorable current amplification.
Date: October 8, 2002
Creator: Hill, D. N.; Blumer, R. H.; Cohen, B. I.; Hooper, E. B.; McLean, H. S.; Moller, J. et al.
System: The UNT Digital Library
Photon Colliders (open access)

Photon Colliders

A photon collider interaction region has the possibility of expanding the physics reach of a future TeV scale electron-positron collider. A survey of ongoing efforts to design the required lasers and optics to create a photon collider is presented in this paper.
Date: October 7, 2002
Creator: Gronberg, J.
System: The UNT Digital Library
The National Ignition Facility: Status and Plans for Laser Fusion and High-Energy-Density Experimental Studies (open access)

The National Ignition Facility: Status and Plans for Laser Fusion and High-Energy-Density Experimental Studies

The National Ignition Facility (NIF), currently under construction at the University of California's Lawrence Livermore National Laboratory, is a stadium-sized facility containing a 192-beam, 1.8-Megajoule, 500-Terawatt, 351-nm laser system and a 10-meter diameter target chamber with room for nearly 100 experimental diagnostics. NIF is being built by the National Nuclear Security Administration and when completed will be the world's largest laser experimental system, providing a national center to study inertial confinement fusion and the physics of matter at extreme energy densities and pressures. NIF will provide 192 energetic laser beams that will compress small fusion targets to conditions where they will ignite and burn, liberating more energy than is required to initiate the fusion reactions. NIF experiments will allow the study of physical processes at temperatures approaching 100 million K and 100 billion times atmospheric pressure. These conditions exist naturally only in the interior of stars and in nuclear weapons explosions. In the course of designing the world's most energetic laser system, a number of significant technology breakthroughs have been achieved. Research is also underway to develop a shorter pulse capability on NIF for very high power and extreme electromagnetic field research and applications. We discuss here the technology challenges …
Date: October 16, 2002
Creator: Moses, E I & Wuest, C R
System: The UNT Digital Library
Development of a Waste Treatment Process to Deactivate Reactive Uranium Metal and Produce a Stable Waste Form (open access)

Development of a Waste Treatment Process to Deactivate Reactive Uranium Metal and Produce a Stable Waste Form

This paper highlights the results of initial investigations conducted to support the development of an integrated treatment process to convert pyrophoric metallic uranium wastes to a non-pyrophoric waste that is acceptable for land disposal. Several dissolution systems were evaluated to determine their suitability to dissolve uranium metal and that yield a final waste form containing uranium specie(s) amenable to precipitation, stabilization, adsorption, or ion exchange. During initial studies, one gram aliquots of uranium metal or the uranium alloy U-2%Mo were treated with 5 to 60 mL of selected reagents. Treatment systems screened included acids, acid mixtures, and bases with and without addition of oxidants. Reagents used included hydrochloric, sulfuric, nitric, and phosphoric acids, sodium hypochlorite, sodium hydroxide and hydrogen peroxide. Complete dissolution of the uranium turnings was achieved with the H{sub 3}PO{sub 4}/HCI system at room temperature within minutes. The sodium hydroxide/hydrogen peroxide, and sodium hypochlorite systems achieved complete dissolution but required elevated temperatures and longer reaction times. A ranking system based on criteria, such as corrosiveness, temperature, dissolution time, off-gas type and amount, and liquid to solid ratio, was designed to determine the treatment systems that should be developed further for a full-scale process. The highest-ranking systems, nitric acid/sulfuric …
Date: January 17, 2002
Creator: Gates-Anderson, D D; Laue, C A & Fitch, T E
System: The UNT Digital Library
Electrical Isolation of ZnO by Ion Irradiation (open access)

Electrical Isolation of ZnO by Ion Irradiation

We demonstrate the formation of highly resistive single-crystal ZnO epilayers as a result of irradiation with MeV Li, O, and Si ions. Results show that the ion doses necessary for electrical isolation close-to-inversely depend on the number of ion-beam-generated atomic displacements. However, in all the cases studied, defect-induced electrical isolation of ZnO is unstable to rapid thermal annealing at temperatures above about 300 C . No significant improvement of thermal stability is found by varying ion mass, dose, and irradiation temperature (up to 350 C). Finally, a comparison of implant isolation in ZnO with that in GaN is presented.
Date: July 3, 2002
Creator: Kucheyev, S. O.; Jagadish, C.; Williams, J. S.; Deenapanray, P. N. K.; Yano, M.; Koike, K. et al.
System: The UNT Digital Library
The LLNL Accelerator Mass Spectrometry System for Biochemical 14C-Measurements (open access)

The LLNL Accelerator Mass Spectrometry System for Biochemical 14C-Measurements

We report on recent improvements made to our 1 MV accelerator mass spectrometry system that is dedicated to {sup 14}C quantification of biochemical samples. Increased vacuum pumping capacity near the high voltage terminal has resulted in a 2-fold reduction of system backgrounds to 0.04 amol {sup 14}C/mg carbon. Carbon ion transmission through the accelerator has also improved a few percent. We have also developed tritium measurement capability on this spectrometer. The {sup 3}H/{sup 1}H isotopic ratio of a milligram-sized processed tap water sample has been measured at 4 {+-} 1 x 10{sup -16} (430 {+-} 110 {micro}Bq/mg H). Measurement throughput for a typical biochemical {sup 3}H sample is estimated to be {approx}10 minutes/sample.
Date: October 31, 2002
Creator: Ognibene, T J; Bench, G; Brown, T A & Vogel, J S
System: The UNT Digital Library
Chronological Reliability Model Incorporating Wind Forecasts to Assess Wind Plant Reserve Allocation: Preprint (open access)

Chronological Reliability Model Incorporating Wind Forecasts to Assess Wind Plant Reserve Allocation: Preprint

Over the past several years, there has been considerable development and application of wind forecasting models. The main purpose of these models is to provide grid operators with the best information available so that conventional power generators can be scheduled as efficiently and as cost-effectively as possible. One of the important ancillary services is reserves, which involves scheduling additional capacity to guard against shortfalls. In a recent paper, Strbac and Kirschen[1] proposed a method to allocate the reserve burden to generators. Although Milligan adapted this technique to wind plants[2], neither of these papers accounts for the wind forecast in the reliability calculation. That omission is rectified here. For the system studied in this paper, we found that a reserve allocation scheme using 1-hour forecasts results in a small allocation of system reserve relative to the rated capacity of the wind power plant. This reserve allocation is even smaller when geographically dispersed wind sites are used instead of a large single site.
Date: May 1, 2002
Creator: Milligan, M. R.
System: The UNT Digital Library
Solid-State Heat-Capacity-Laser Review (open access)

Solid-State Heat-Capacity-Laser Review

We describe our recent progress in the area of solid-state heat-capacity-lasers (SSHCL). In particular, we examine the physics of heat-capacity operation of a solid state laser and give the present technology status of our 10 kW flashlamp-pumped laser The current status of work leading to a diode-pumped Nd:GGG HCL is also described.
Date: May 7, 2002
Creator: Rotter, M D & Dane, C B
System: The UNT Digital Library
Advances in Low-Defect Multilayers for EUVL Mask Blanks (open access)

Advances in Low-Defect Multilayers for EUVL Mask Blanks

Low-defect multilayer coatings are required to fabricate mask blanks for Extreme Ultraviolet Lithography (EUVL). The mask blanks consist of high reflectance E W multilayers on low thermal expansion substrates. A defect density of 0.0025 printable defects/cm{sup 2} for both the mask substrate and the multilayer is required to provide a mask blank yield of 60%. Current low defect multilayer coating technology allows repeated coating-added defect levels of 0.05/cm{sup 2} for defects greater than 90 nm polystyrene latex sphere (PSL) equivalent size for lots of 20 substrates. Extended clean operation of the coating system at levels below 0.08/cm{sup 2} for 3 months of operation has also been achieved. Two substrates with zero added defects in the quality area have been fabricated, providing an existence proof that ultra low defect coatings are possible. Increasing the ion source-to-target distance from 410 to 560 mm to reduce undesired coating of the ion source caused the defect density to increase to 0.2/cm{sup 2}. Deposition and etching diagnostic witness substrates and deposition pinhole cameras showed a much higher level of ion beam spillover (ions missing the sputter target) than expected. Future work will quantify beam spillover, and test designs to reduce spillover, if it is confirmed …
Date: April 15, 2002
Creator: Folta, J. A.; Davidson, J. C.; Larson, C. C.; Walton, C. C. & Kearney, P. A.
System: The UNT Digital Library