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7,180 Matching Results
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U.S.-EU Trade and Economic Relations: Key Policy Issues for the 112th Congress
U.S. and European private stakeholders, concerned about slow growth, job creation, and increased competition from emerging economies, have urged Brussels and Washington to strengthen transatlantic trade and economic ties by reducing or eliminating remaining trade barriers and by cooperating more closely in addressing global economic challenges. A select group of these issues are examined in this report.
Date:
December 22, 2011
Creator:
Ahearn, Raymond J.
Object Type:
Report
System:
The UNT Digital Library
Vietnam: Economic/Political Developments and U.S. Relations
This report provides an overview of the economic/political developments in Vietnam, including their relationship with the United States.
Date:
November 22, 1996
Creator:
Ahearn, Raymond J. & Stutter, Robert G.
Object Type:
Report
System:
The UNT Digital Library
Study to define the shock and vibration environment during truck transport of shipping containers. Summary report
None
Date:
December 22, 1971
Creator:
Ahlbeck, D. R.
Object Type:
Report
System:
The UNT Digital Library
RIA R&D for Enabling Direct Neutron Cross-Section Measurements
The expected production rates at RIA imply it should be possible to collect 10-{micro}g of a one-day half-life isotope. The amount of material should be sufficient to enable direct neutron cross-section measurements for many unstable isotopes. This capability is crucial for many of the stockpile stewardship and some of the astrophysical cross-section measurements. Enabling this capability at RIA requires the ability to harvest the desired isotopes, process highly radioactive material into targets, and irradiate targets with neutrons. This paper will discuss the changes and additions to the RIA complex that are necessary in order to enable direct neutron cross-section measurements. This will include a discussion of harvesting as well as a conceptual design for a co-located experimental facility with radiochemistry capability and a variable 'mono-energetic' neutron source.
Date:
August 22, 2003
Creator:
Ahle, L. E.; Rusnak, B. & Stoyer, M.
Object Type:
Article
System:
The UNT Digital Library
Initial experiments of RF gas plasma source for heavy ionfusion
The Source Injector Program for the US Heavy Ion Fusion Virtual National Laboratory is currently exploring the feasibility of using RF gas plasma sources for a HIF driver. This source technology is presently the leading candidate for the multiple aperture concept, in which bright millimeter size beamlets are extracted and accelerated electrostatically up to 1 MeV before the beamlets are allowed to merge and form 1 A beams. Initial experiments have successfully demonstrated simultaneously high current density, {approx} 100 mA/cm{sup 2} and fast turn on, {approx} 1 {micro}s. These experiments were also used to explore operating ranges for pressure and RF power. Results from these experiments are presented as well as progress and plans for the next set of experiments for these sources.
Date:
May 22, 2002
Creator:
Ahle, L.; Hall, R.; Molvik, A. W.; Chacon-Golcher, E.; Kwan, J. W.; Leung, K. N. et al.
Object Type:
Article
System:
The UNT Digital Library
RF gas plasma source development for heavy ion fusion
Presently the Heavy Ion Fusion Virtual National Laboratory is researching ion sources and injector concepts to understand how to optimize beam brightness over a range of currents (50-2000 mA argon equivalent). One concept initially accelerates millimeter size, milliamp beamlets to 1 MeV before merging them into centimeter size, ampere beams. Computer simulations have shown the final brightness of the merged beams is dominated by the emittance growth of the merging process, as long as the beamlets ion temperature is below a few eV. Thus, a RF multicusp source capable of high current density can produce beams with better brightness compared to ones extracted from a colder source with a large aperture and lower current density. As such, experiments have begun to develop a RF multicusp source capable of delivering one amp of extracted beam current. It is expected that it will require 10 kW of 13 MHz RF power delivered via a quartz shielded, one and half turn, four inch diameter antenna. Important considerations in the development of the source include the dependence of current density and beam ion temperature on consumed RF power and gas pressure. A fast rise time ({approx}100 ns) for the extracted beam pulse must also …
Date:
February 22, 2002
Creator:
Ahle, L.E.; Hall, R.P. & Molvik, A.W.
Object Type:
Article
System:
The UNT Digital Library
Nuclear structure studies from prompt gamma-ray spectroscopy of fission fragments.
None
Date:
June 22, 2000
Creator:
Ahmad, I.
Object Type:
Article
System:
The UNT Digital Library
X-ray diffraction diagnostic design for the National Ignition Facility
None
Date:
August 22, 2013
Creator:
Ahmed, M F; Ayers, J; House, A; Lamb, Z; Swift, R & Swift, D
Object Type:
Article
System:
The UNT Digital Library
EARLY ENTRANCE COPRODUCTION PLANT
The overall objective of this project is the three phase development of an Early Entrance Coproduction Plant (EECP) which produces at least one product from at least two of the following three categories: (1) electric power (or heat), (2) fuels, and (3) chemicals. The objective is to have these products produced by technologies capable of using synthesis gas derived from coal and/or other carbonaceous feedstocks. The objective of Phase I is to determine the feasibility and define the concept for the EECP located at a specific site; develop a Research, Development, and Testing (RD&T) Plan for implementation in Phase II; and prepare a Preliminary Project Financing Plan. The objective of Phase II is to implement the work as outlined in the Phase I RD&T Plan to enhance the development and commercial acceptance of coproduction technology that produces high-value products, particularly those that are critical to our domestic fuel and power requirements. The project will resolve critical knowledge and technology gaps on the integration of gasification and downstream processing to coproduce some combination of power, fuels, and chemicals from coal and/or other carbonaceous feedstocks. The objective of Phase III is to develop an engineering design package and a financing and testing …
Date:
November 22, 2002
Creator:
Ahmed, Mushtaq; Anderson, John H.; Berry, Earl R.; Brent, Fred; He, Ming; Ong, Jimmy O. et al.
Object Type:
Report
System:
The UNT Digital Library
Fuel processing for fuel cell powered vehicles.
A number of auto companies have announced plans to have fuel cell powered vehicles on the road by the year 2004. The low-temperature polymer electrolyte fuel cells to be used in these vehicles require high quality hydrogen. Without a hydrogen-refueling infrastructure, these vehicles need to convert the available hydrocarbon fuels into a hydrogen-rich gas on-board the vehicle. Earlier analysis has shown that fuel processors based on partial oxidation reforming are well suited to meet the size and weight targets and the other performance-related needs of on-board fuel processors for light-duty fuel cell vehicles (1).
Date:
January 22, 1999
Creator:
Ahmed, S.; Wilkenhoener, R.; Lee, S. H. D.; Carter, J. D.; Kumar, R. & Krumpelt, M.
Object Type:
Article
System:
The UNT Digital Library
Improvement in Car-Couplings.
Patent for an improvement to car couplings which would "obviate the necessity and its attendant danger of going between the cars" (lines 17-18) including an illustration.
Date:
July 22, 1879
Creator:
Ahrenbeck, C.
Object Type:
Patent
System:
The Portal to Texas History
Photoconductive properties of GaAs{sub 1{minus}x}N{sub x} double heterostructures as a function of excitation wavelength
The ternary semiconductor GaAs{sub 1{minus}x}N{sub x} with 0 < x < 0.3 can be grown epitaxially on GaAs and has a very large bowing coefficient. The alloy bandgap can be reduced to about 1.0 eV with about a 3% nitrogen addition. In this work, the authors measured the internal spectral response and recombination lifetime of a number of alloys using the ultra-high frequency photoconductive decay (UHFPCD) method. The data shows that the photoconductive excitation spectra of the GaAs{sub 0.97}N{sub 0.03} alloy shows a gradual increase in response through the absorption edge near E{sub g}. This contrasts with most direct bandgap semiconductors that show a steep onset of photoresponse at E{sub g}. The recombination lifetimes frequently are much longer than expected from radiative recombination and often exceeded 1.0{mu}s. The data were analyzed in terms of a band model that includes large potential fluctuations in the conduction band due to the random distribution of nitrogen atoms in the alloy.
Date:
May 22, 2000
Creator:
Ahrenkiel, R. K.; Mascarenhas, A.; Johnston, S. W.; Zhang, Y.; Friedman, D. J. & Vernon, S. M.
Object Type:
Article
System:
The UNT Digital Library
Acoustic Separation Technology
Today's restrictive environmental regulations encourage paper mills to close their water systems. Closed water systems increase the level of contaminants significantly. Accumulations of solid suspensions are detrimental to both the papermaking process and the final products. To remove these solids, technologies such as flotation using dissolved air (DAF), centrifuging, and screening have been developed. Dissolved Air Flotation systems are commonly used to clarify whitewater. These passive systems use high pressure to dissolve air into whitewater. When the pressure is released, air micro-bubbles form and attach themselves to fibers and particles, which then float to the surface where they are mechanically skimmed off. There is an economic incentive to explore alternatives to the DAF technology to drive down the cost of whitewater processing and minimize the use of chemicals. The installed capital cost for a DAF system is significant and a typical DAF system takes up considerable space. An alternative approach, which is the subject of this project, involves a dual method combining the advantages of chemical flocculation and in-line ultrasonic clarification to efficiently remove flocculated contaminants from a water stream
Date:
February 22, 2002
Creator:
Ahrens, Fred & Patterson, Tim
Object Type:
Report
System:
The UNT Digital Library
Wire Stretcher.
Patent for a new and improved wire stretcher. This design consists in "a frame having two arms, one carrying a fixed clamp and the other a roller, a windlass mounted on said frame having a rope passing over said roller and adapted to be fixed to an end of wire, and a central clamp consisting of a rigid bar on the frame between its arms, a notched clamp pivoted thereon, and a ring for retaining the clamp" (lines 6-14).
Date:
February 22, 1887
Creator:
Ainsworth, Phineas Hardaman
Object Type:
Patent
System:
The Portal to Texas History
Global Cooling: Effect of Urban Albedo on Global Temperature
In many urban areas, pavements and roofs constitute over 60% of urban surfaces (roof 20-25%, pavements about 40%). The roof and the pavement albedo can be increased by about 0.25 and 0.10, respectively, resulting in a net albedo increase for urban areas of about 0.1. Many studies have demonstrated building cooling-energy savings in excess of 20% upon raising roof reflectivity from an existing 10-20% to about 60%. We estimate U.S. potential savings in excess of $1 billion (B) per year in net annual energy bills. Increasing albedo of urban surfaces can reduce the summertime urban temperature and improve the urban air quality. Increasing the urban albedo has the added benefit of reflecting more of the incoming global solar radiation and countering the effect of global warming. We estimate that increasing albedo of urban areas by 0.1 results in an increase of 3 x 10{sup -4} in Earth albedo. Using a simple global model, the change in air temperature in lowest 1.8 km of the atmosphere is estimated at 0.01K. Modelers predict a warming of about 3K in the next 60 years (0.05K/year). Change of 0.1 in urban albedo will result in 0.01K global cooling, a delay of {approx}0.2 years in …
Date:
May 22, 2007
Creator:
Akbari, Hashem; Menon, Surabi & Rosenfeld, Arthur
Object Type:
Article
System:
The UNT Digital Library
Phase change in uranium: Discrepancy between experiment and theory
Using a diamond-anvil cell (DAC) phase transformation and room temperature Equation of State (EOS) for some actinides and lanthanides were studied to multimegabar (megabar = 100 GPa) pressures. Experimental data are compared with the theoretically predicted crystal structural changes and the pressure-volume relationships. There is a general agreement between theory and experiment for the structural changes in the lighter actinides, however in detail there are some discrepancies still. A generalized trend for the phase transformations in the lanthanides can be seen, which again has broad agreement with theory. We conclude that an accurate and robust theoretical base for predicting the phase transformations in the f-electron metals can be developed by incorporating the DAC data.
Date:
July 22, 1996
Creator:
Akella, J.
Object Type:
Report
System:
The UNT Digital Library
Export-Import Bank Reauthorization: Frequently Asked Questions
None
Date:
December 22, 2014
Creator:
Akhtar, Shayerah Ilias; Carpenter, David H.; Levit, Mindy R. & Taylor, Julia
Object Type:
Report
System:
The UNT Digital Library
Development of a Novel Catalyst for NO Decomposition
Air pollution arising from the emission of nitrogen oxides as a result of combustion taking place in boilers, furnaces and engines, has increasingly been recognized as a problem. New methods to remove NO{sub x} emissions significantly and economically must be developed. The current technology for post-combustion removal of NO is the selective catalytic reduction (SCR) of NO by ammonia or possibly by a hydrocarbon such as methane. The catalytic decomposition of NO to give N{sub 2} will be preferable to the SCR process because it will eliminate the costs and operating problems associated with the use of an external reducing species. The most promising decomposition catalysts are transition metal (especially copper)-exchanged zeolites, perovskites, and noble metals supported on metal oxides such as alumina, silica, and ceria. The main shortcoming of the noble metal reducible oxide (NMRO) catalysts is that they are prone to deactivation by oxygen. It has been reported that catalysts containing tin oxide show oxygen adsorption behavior that may involve hydroxyl groups attached to the tin oxide. This is different than that observed with other noble metal-metal oxide combinations, which have the oxygen adsorbing on the noble metal and subsequently spilling over to the metal oxide. This observation …
Date:
June 22, 2007
Creator:
Akyurtlu, Ates & Akyurtlu, Jale F.
Object Type:
Report
System:
The UNT Digital Library
Development of a Novel Catalyst for NO Decomposition
Air pollution arising from the emission of nitrogen oxides as a result of combustion taking place in boilers, furnaces and engines, has increasingly been recognized as a problem. New methods to remove NO{sub x} emissions significantly and economically must be developed. The current technology for post-combustion removal of NO is the selective catalytic reduction (SCR) of NO by ammonia or possibly by a hydrocarbon such as methane. The catalytic decomposition of NO to give N{sub 2} will be preferable to the SCR process because it will eliminate the costs and operating problems associated with the use of an external reducing species. The most promising decomposition catalysts are transition metal (especially copper)-exchanged zeolites, perovskites, and noble metals supported on metal oxides such as alumina, silica, and ceria. The main shortcoming of the noble metal reducible oxide (NMRO) catalysts is that they are prone to deactivation by oxygen. It has been reported that catalysts containing tin oxide show oxygen adsorption behavior that may involve hydroxyl groups attached to the tin oxide. This is different than that observed with other noble metal-metal oxide combinations, which have the oxygen adsorbing on the noble metal and subsequently spilling over to the metal oxide. This observation …
Date:
October 22, 2004
Creator:
Akyurtlu, Ates & Akyurtlu, Jale F.
Object Type:
Report
System:
The UNT Digital Library
[Generation of a synthetic seismic data base]. Final report
A consortium (Los Alamos, Sandia, OR, Livermore) have been collaborating under the GONII project to generate a synthetic seismic data base. Two deliverables were a common code that would run on the various site machines, and the use of these codes to generate parts of the final data base. The data base consists of a large number of shots applied to two geographic models developed by another part of GONII, the salt model and the overthrust model,s which were supplied as large files containing propagation velocity on a 3-D grid. Los Alamos was supplied with the source code of a seismic propagation code written by the French Petroleum Institute. A decision was made to port a subset of the code to Fortran on a node. Part of this contract was spent verifying/debugging the Fortran on a node code; a port of the code was made to run on the Cray. A total of 846 shots were run on the CM5. It was found that files on the SDA are not safe from corruption and the model velocity file may change.
Date:
October 22, 1995
Creator:
Aldrich, C. H., III
Object Type:
Report
System:
The UNT Digital Library
On reactor type comparisons for the next generation of reactors
In this paper, we present a broad comparison of studies for a selected set of parameters for different nuclear reactor types including the next generation. This serves as an overview of key parameters which provide a semi-quantitative decision basis for selecting nuclear strategies. Out of a number of advanced reactor designs of the LWR type, gas cooled type, and FBR type, currently on the drawing board, the Advanced Light Water Reactors (ALWR) seem to have some edge over other types of the next generation of reactors for the near-term application. This is based on a number of attributes related to the benefit of the vast operating experience with LWRs coupled with an estimated low risk profile, economics of scale, degree of utilization of passive systems, simplification in the plant design and layout, modular fabrication and manufacturing. 32 refs., 1 fig., 3 tabs.
Date:
August 22, 1991
Creator:
Alesso, H.P. & Majumdar, K.C.
Object Type:
Article
System:
The UNT Digital Library
Correlating radiation exposure with embrittlement: Comparative studies of electron- and neutron-irradiated pressure vessel alloys
Comparative experiments using high energy (10 MeV) electrons and test reactor neutrons have been undertaken to understand the role that primary damage state has on hardening (embrittlement) induced by irradiation at 300 C. Electrons produce displacement damage primarily by low energy atomic recoils, while fast neutrons produce displacements from considerably higher energy recoils. Comparison of changes resulting from neutron irradiation, in which nascent point defect clusters can form in dense cascades, with electron irradiation, where cascade formation is minimized, can provide insight into the role that the in-cascade point defect clusters have on the mechanisms of embrittlement. Tensile property changes induced by 10 MeV electrons or test reactor neutron irradiations of unalloyed iron and an Fe-O.9 wt.% Cu-1.0 wt.% Mn alloy were examined in the damage range of 9.0 x 10{sup {minus}5} dpa to 1.5 x 10{sup {minus}2} dpa. The results show the ternary alloy experienced substantially greater embrittlement in both the electron and neutron irradiate samples relative to unalloyed iron. Despite their disparate nature of defect production similar embrittlement trends with increasing radiation damage were observed for electrons and neutrons in both the ternary and unalloyed iron.
Date:
December 22, 1999
Creator:
Alexander, D. E.; Rehn, L. E.; Odette, G. R.; Lucas, G. E.; Klingensmith, D. & Gragg, D.
Object Type:
Article
System:
The UNT Digital Library
The International Whaling Convention (IWC) and Legal Issues Related to Aboriginal Rights
This report discusses the recent legislation regarding whaling in general, and aboriginal whaling in particular. Legislative measures, primarily in the form of concurrent resolutions, have been proposed in four categories: protesting commercial, scientific, or community (nonaboriginal) whaling; ensuring aboriginal whaling rights; providing a tax break for aboriginal whaling captains; and addressing the United States' policy at the annual meetings of the IWC.
Date:
July 22, 2013
Creator:
Alexander, Kristina
Object Type:
Report
System:
The UNT Digital Library
K Reactor moderator distortion study
Irradiation-induced moderator distortion has plagued the Hanford reactors from their earliest days until the present. The first-manifestation of graphite distortion was in the form of expansion of the B, D and F stacks. It was found that expansion was very temperature-dependent and could be reversed by raising the graphite operating temperature. The DR, H, C and K Reactors were designed with provisions to minimize, or accommodate expansion. It was not until after the K Reactors had been designed that graphite contraction was recognized as a threat to stack life. Under the present operating conditions, contraction is largely dependent upon neutron flux levels. To date, this study has been largely concerned with the K Reactors, since the vast bulk of the distortion data available is from the Ks. This study not only attempts to explain the mechanisms by which the K Reactors arrived at their present state of distortion but also provides a basis for forecasting future distortion. An understanding of the nature and magnitude of the forces at work within the stacks will enhance the possibility of devising means of conteracting the present trends.
Date:
June 22, 1964
Creator:
Alexander, W.K. & Russell, A.
Object Type:
Report
System:
The UNT Digital Library