Resource Type

0.52eV Quaternary InGaAsSb Thermophotovoltaic Diode Technology (open access)

0.52eV Quaternary InGaAsSb Thermophotovoltaic Diode Technology

Thermophotovoltaic (TPV) diodes fabricated from 0.52eV lattice-matched InGaAsSb alloys are grown by Metal Organic Vapor Phase Epitaxy (MOVPE) on GaSb substrates. 4cm{sup 2} multi-chip diode modules with front-surface spectral filters were tested in a vacuum cavity and attained measured efficiency and power density of 19% and 0.58 W/cm{sup 2} respectively at operating at temperatures of T{sub radiator} = 950 C and T{sub diode} = 27 C. Device modeling and minority carrier lifetime measurements of double heterostructure lifetime specimens indicate that diode conversion efficiency is limited predominantly by interface recombination and photon energy loss to the GaSb substrate and back ohmic contact. Recent improvements to the diode include lattice-matched p-type AlGaAsSb passivating layers with interface recombination velocities less than 100 cm/s and new processing techniques enabling thinned substrates and back surface reflectors. Modeling predictions of these improvements to the diode architecture indicate that conversion efficiencies from 27-30% and {approx}0.85 W/cm{sup 2} could be attained under the above operating temperatures.
Date: June 9, 2004
Creator: Dashiell, M. W.; Beausang, J. F.; Nichols, G.; Depoy, D. M.; Danielson, L. R.; Ehsani, H. et al.
System: The UNT Digital Library
100 Areas weekly report, June 9, 1955 (open access)

100 Areas weekly report, June 9, 1955

None
Date: June 9, 1955
Creator: Bellas, H. W.
System: The UNT Digital Library
The ACA Prevention and Public Health Fund: In Brief (open access)

The ACA Prevention and Public Health Fund: In Brief

This report provides background information on the Affordable Care Act (ACA) and discusses the authority and funding distributions.
Date: June 9, 2017
Creator: Lister, Sarah A.
System: The UNT Digital Library
Acoustic emission from beryllium (open access)

Acoustic emission from beryllium

The acoustic emission from both powder and ingot source beryllium has been measured as a function of strain and prior heat treatment. Most measurements were made during tensile deformation, but a limited number of compression tests have also been performed. The acoustic emission observed was of the burst type, with little or no contribution from continuous type emission. The emission was characterized by the variation of burst rate and average energy per burst as a function of strain. The tensile behavior was qualitatively similar for all the materials tested. Burst rate maxima centered roughly at 0.1 percent and 1.0 percent plastic strain were observed. The magnitude but not the strain at the low strain burst rate peak was very sensitive to prior thermal treatment, while the higher strain burst rate peak was insensitive to prior heat treatment. An energy per burst maximum was observed at 0.2 percent plastic strain, the magnitude of which was moderately sensitive to heat treatment. The Kaiser effect is observed in the material studied. Emission during compression was similar to that observed in tension. The acoustic emission observed is attributed to dislocation motion, as proposed by James and Carpenter for LiF, NaCl, and Zn. Metallographic studies …
Date: June 9, 1976
Creator: Heiple, C. R. & Adams, R. O.
System: The UNT Digital Library
Advective Flux in Relation to Net Ecosystem CO2 Exchange at the NIWOT Ridge Ameriflux Site (open access)

Advective Flux in Relation to Net Ecosystem CO2 Exchange at the NIWOT Ridge Ameriflux Site

This report describes final progress made on measurements of advective CO2 flux to the overall forest carbon budget at the Niwot Ridge Ameriflux site in Colorado.
Date: June 9, 2005
Creator: Monson, Russell K.
System: The UNT Digital Library
Aerial Radiological Surveys (open access)

Aerial Radiological Surveys

Measuring terrestrial gamma radiation from airborne platforms has proved to be a useful method for characterizing radiation levels over large areas. Over 300 aerial radiological surveys have been carried out over the past 25 years including U.S. Department of Energy (DOE) sites, commercial nuclear power plants, Formerly Utilized Sites Remedial Action Program/Uranium Mine Tailing Remedial Action Program (FUSRAP/UMTRAP) sites, nuclear weapons test sites, contaminated industrial areas, and nuclear accident sites. This paper describes the aerial measurement technology currently in use by the Remote Sensing Laboratory (RSL) for routine environmental surveys and emergency response activities. Equipment, data-collection and -analysis methods, and examples of survey results are described.
Date: June 9, 1997
Creator: Proctor, A. E.
System: The UNT Digital Library
Africa: U.S. Foreign Assistance Issues (open access)

Africa: U.S. Foreign Assistance Issues

This report discusses the issue of U.S. economic assistance to sub-Saharan Africa, highlighting the importance of continued assistance in light of U.S. national security and also various U.S.-led efforts to promote reform amongst African citizens themselves. U.S. assistance finds its way to Africa through a variety of channels, including the USAID-administered DA program, food aid programs, and indirect aid provided through international financial institutions and the United Nations.
Date: June 9, 2005
Creator: Copson, Raymond W.
System: The UNT Digital Library
Airline Deregulation: Reregulating the Airline Industry Would Likely Reverse Consumer Benefits and Not Save Airline Pensions (open access)

Airline Deregulation: Reregulating the Airline Industry Would Likely Reverse Consumer Benefits and Not Save Airline Pensions

A letter report issued by the Government Accountability Office with an abstract that begins "The Airline Deregulation Act of 1978 phased out the government's control over fares and service and allowed market forces to determine the price and level of domestic airline service in the United States. The intent was to increase competition and thereby lead to lower fares and improved service. In 2005, GAO reported on the tenuous finances of some airlines that have led to bankruptcy and pension terminations, in particular among those airlines that predated deregulation (referred to as legacy airlines). The House Report accompanying the 2006 Department of Transportation (DOT) Appropriation Act expressed concern about airline pension defaults and charged GAO with analyzing the impact of reregulating the airline industry on reducing potential pension defaults by airlines. GAO subsequently agreed to address the pension issue within a broad assessment of the airline industry since deregulation. Specifically, GAO is reporting on, among other things, (1) broad airline industry changes since deregulation, (2) fare and service changes since deregulation, and (3) whether there is evidence that reregulation of entry and fares would benefit consumers or the airline industry, or save airline pensions. DOT agreed with the conclusions in …
Date: June 9, 2006
Creator: United States. Government Accountability Office.
System: The UNT Digital Library
The Alaska Natural Gas Pipeline: Background, Status, and Issues for Congress (open access)

The Alaska Natural Gas Pipeline: Background, Status, and Issues for Congress

This report concerns itself with the construction of an Alaska natural gas pipeline. The report considers the funding available for a natural gas pipeline and the potential for it to stimulate the economy. Moreover, the report discusses how the 2008 recession poses an obstacle to the creation of the pipeline due to it causing low gas prices.
Date: June 9, 2011
Creator: Parfomak, Paul W.
System: The UNT Digital Library
Altitude performance investigation of single- and double-annular turbojet-engine combustors with various size fuel nozzles (open access)

Altitude performance investigation of single- and double-annular turbojet-engine combustors with various size fuel nozzles

From Introduction: "The purpose of the investigation conducted at the NACA Lewis laboratory and reported herein was to determine the improvements possible in full-scale turbojet-engine performance when a single-annular combustor with slotted air-inlet orifices was used."
Date: June 9, 1952
Creator: Harp, James L., Jr. & Vincent, Kenneth R.
System: The UNT Digital Library
Ambient Laboratory Coater for Advanced Gas Reactor Fuel Development (open access)

Ambient Laboratory Coater for Advanced Gas Reactor Fuel Development

this research is targeted at developing improved experimentally-based scaling relationships for the hydrodynamics of shallow, gas-spouted beds of dense particles. The work is motivated by the need to more effctively scale up shallow spouted beds used in processes such as in the coating of nuclear fuel particles where precise control of solids and gas circulation is critically important. Experimental results reported here are for a 50 mm diameter spouted bed containing two different types of bed solids (alumina and zirconia) at different static bed depths and fluidized by air and helium. Measurements of multiple local average pressures, inlet gas pressure fluctuations, and spout height were used to characterize the bed hydrodynamics for each operating condition. Follow-on studies are planned that include additional variations in bed size, particle properties, and fluidizing gas. The ultimate objective is to identify the most important non-dimensional hydrodynamic scaling groups and possible spouted-bed design correlations based on these groups.
Date: June 9, 2010
Creator: Bruns, Duane D.; Counce, Robert M. & Rojas, Irma D. Lima
System: The UNT Digital Library
Analysis of Recombination Processes in 0.5-0.6 eV Epitaxial GaInAsSb Lattice-matched to GaSb (open access)

Analysis of Recombination Processes in 0.5-0.6 eV Epitaxial GaInAsSb Lattice-matched to GaSb

This work summarizes recent data on minority carrier lifetime in n- and p-type double heterostructures (DHs) of 0.5-0.6 eV GaInAsSb confined with GaSb and AlGaAsSb cap layers. Recombination times were measured by time-resolved photoluminescence (TRPL) and by optical frequency response (OFR) to sinusoidal excitation. It was shown that one of the mechanisms responsible for interface recombination in GaSb/GaInAsSb/GaSb DHs is thermionic emission of carriers over the heterobarrier. Considerable improvement of carrier confinement was obtained with 1 eV AlGaAsSb cap layers. Optimization of the epitaxial growth resulted in a recombination velocity at GaInAsSb/AlGaAsSb interface as low as 30 cm/s.
Date: June 9, 2004
Creator: Donetsky, D.; Anikeev, S.; Gu, N.; Belenky, G.; Luryi, S.; Wang, C. A. et al.
System: The UNT Digital Library
An analysis of the supreme court Ruling in Village of Arlington Heights V. (open access)

An analysis of the supreme court Ruling in Village of Arlington Heights V.

This report is about an analysis of the supreme court ruling in village of arlington heights V. Metropolitan housing development corp. : proving racial discrimination in local land use policies
Date: June 9, 1977
Creator: Dale, Charles E.
System: The UNT Digital Library
Annotation of the Clostridium Acetobutylicum Genome (open access)

Annotation of the Clostridium Acetobutylicum Genome

The genome sequence of the solvent producing bacterium Clostridium acetobutylicum ATCC824, has been determined by the shotgun approach. The genome consists of a 3.94 Mb chromosome and a 192 kb megaplasmid that contains the majority of genes responsible for solvent production. Comparison of C. acetobutylicum to Bacillus subtilis reveals significant local conservation of gene order, which has not been seen in comparisons of other genomes with similar, or, in some cases, closer, phylogenetic proximity. This conservation allows the prediction of many previously undetected operons in both bacteria.
Date: June 9, 2004
Creator: Daly, M. J.
System: The UNT Digital Library
Antimony Based III-V Thermophotovoltaic Devices (open access)

Antimony Based III-V Thermophotovoltaic Devices

Antimony-based III-V thermophotovoltaic (TPV) cells are attractive converters for systems with low radiator temperature around 1100 to 1700 K, since these cells potentially can be spectrally matched to the thermal source. Cells under development include GaSb and the lattice-matched GaInAsSb/GaSb and InPAsSb/InAs quaternary systems. GaSb cell technology is the most mature, owing in part to the relative ease in preparation of the binary alloy compared to quaternary GaInAsSb and InPAsSb alloys. Device performance of 0.7-eV GaSb cells exceeds 90% of the practical limit. GaInAsSb TPV cells have been the primary focus of recent research, and cells with energy gap E{sub g} ranging from {approx}0.6 to 0.49 eV have been demonstrated. Quantum efficiency and fill factor approach theoretical limits. Open-circuit voltage factor is as high as 87% of the practical limit for the higher-E{sub g} cells, but degrades to below 80% with decreasing E{sub g} of the alloy, which might be due to Auger recombination. InPAsSb cells are the least studied, and a cell with E{sub g} = 0.45-eV has extended spectral response out to 4.3 {micro}m. This paper briefly reviews the main contributions that have been made for antimonide-based TPV cells, and suggests additional studies for further performance enhancements.
Date: June 9, 2004
Creator: Wang, C. A.
System: The UNT Digital Library
Army Corps of Engineers Civil Works Program: Issues for the 109th Congress (open access)

Army Corps of Engineers Civil Works Program: Issues for the 109th Congress

This report presents the issues considered by the 109th Congress related to the civil works program of the U.S. Army Corps of Engineers (Corps). The Corps plans, constructs, and operates water resources facilities primarily for flood control, navigation, and environmental purposes.
Date: June 9, 2005
Creator: Carter, Nicole T.; Hughes, H. Steven & Sheikh, Pervaze A.
System: The UNT Digital Library
Authorization for a process change -- Revision of nuclear safety rules for transporting plutonium compounds between the 231 and 234-5 Buildings (open access)

Authorization for a process change -- Revision of nuclear safety rules for transporting plutonium compounds between the 231 and 234-5 Buildings

Nuclear safety rules for transporting plutonium compounds between the 231 and 234-5 Buildings were established in Documents HW-30328 and HW-31465. Provisions for the co-transporting of loaded sample cans, filter boats and/or product samples were not included in the above documents. In the interest of economy and efficiency the rules have been reviewed and revised according to the provisions set forth in this document. The paper describes the present transportation limits and the revised limits for transporting plutonium nitrate, plutonium oxalate, and other plutonium samples. The limits are in keeping with the policy of preventing the accidental accumulation of unsafe masses of Pu.
Date: June 9, 1954
Creator: Smith, A. E.
System: The UNT Digital Library
Avian Flu Pandemic: Potential Impact of Trade Disruptions (open access)

Avian Flu Pandemic: Potential Impact of Trade Disruptions

Concerns about potential disruptions in U.S. trade flows due to a global health or security risk are not new. The possibility of an avian flu pandemic with consequences for global trade is a concern that has received more attention recently, although some experts believe there is little cause for alarm. Experts disagree on the likelihood of an avian flu pandemic developing at all. This report considers possible trade disruptions, including possible impacts on trade between the United States and countries and regions that have reported avian influenza infections. These disruptions could include countries banning imported goods from infected regions at the onset of the pandemic, de facto bans due to protective health measures, or supply-side constraints caused by health crises in exporting countries.
Date: June 9, 2006
Creator: Langton, Danielle
System: The UNT Digital Library
Axions in String Theory (open access)

Axions in String Theory

In the context of string theory, axions appear to provide the most plausible solution of the strong CP problem. However, as has been known for a long time, in many string-based models, the axion coupling parameter Fa is several orders of magnitude higher than the standard cosmological bounds. We re-examine this problem in a variety of models, showing that Fa is close to the GUT scale or above in many models that have GUT-like phenomenology, as well as some that do not. On the other hand, in some models with Standard Model gauge fields supported on vanishing cycles, it is possible for Fa to be well below the GUT scale.
Date: June 9, 2006
Creator: Svrcek, Peter; /Stanford U., Phys. Dept. /SLAC; Witten, Edward & /Princeton, Inst. Advanced Study
System: The UNT Digital Library
B&D power and water plant modifications and operation after deactivation of D reactors (open access)

B&D power and water plant modifications and operation after deactivation of D reactors

Pursuant to the decision of the Atomic Energy Commission to deactivate a fourth Hanford production reactor, engineering studies were initiated in regard to the water supply and distribution systems of the smaller production reactor complex. It was the intent of these studies to effect optimization of the water supply and distribution system which would result in a more effective operation and would continue to meet existing standards and requirements. It is the purpose of this report to document the results of the engineering studies and to describe the functional requirements of the overall water supply and distribution systems.
Date: June 9, 1967
Creator: Brinkman, L. B.
System: The UNT Digital Library
Bahrain: Reform, Security, and U.S. Policy (open access)

Bahrain: Reform, Security, and U.S. Policy

This report discusses Reform, Security, and U.S. Policy in Bahrain.
Date: June 9, 2011
Creator: Katzman, Kenneth
System: The UNT Digital Library
Balkan Cooperation on War Crimes Issues: 2005 Update (open access)

Balkan Cooperation on War Crimes Issues: 2005 Update

A combination of intensified international pressure and deadlines associated with Euro-Atlantic integration processes has prompted a spate of transfers of persons indicted for war crimes to the International Criminal Tribunal for the former Yugoslavia (ICTY) in The Hague in late 2004-early 2005. Full cooperation with The Hague tribunal has been established as a key prerequisite to further progress toward a shared long-term goal for the western Balkan countries: closer association with and eventual membership in the European Union (EU) and NATO. This report is updated as the number of individuals indicted for war crimes have been transferred to The Hague from Serbia, Kosovo, and Bosnia.
Date: June 9, 2005
Creator: Kim, Julie
System: The UNT Digital Library
The Bayh-Dole Act: Selected Issues in Patent Policy and the Commercialization of Technology (open access)

The Bayh-Dole Act: Selected Issues in Patent Policy and the Commercialization of Technology

This report is categorized into Five categories: (I) Introduction, (II) An Historical Perspective, (III) Bayh-Dole Act and Related Law, (IV) Current Issues and Concerns, and (V) Concluding Observations.
Date: June 9, 2011
Creator: Schacht, Wendy H.
System: The UNT Digital Library
Beowawe Prospect, Eureka County, Nevada, Getty Oil Company, Temperature depth data, shallow holes, 16 wells 200-500 ft depths (open access)