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Activated transport in AMTEC electrodes (open access)

Activated transport in AMTEC electrodes

Transport of alkali metal atoms through porous cathodes of alkali metal thermal-to-electric converter (AMTEC) cells is responsible for significant, reducible losses in the electrical performance of these cells. Experimental evidence for activated transport of metal atoms at grain surfaces and boundaries within some AMTEC electrodes has been derived from temperature dependent studies as well as from analysis of the detailed frequency dependence of ac impedance results for other electrodes, including thin, mature molybdenum electrodes which exhibit transport dominated by free molecular flow of sodium gas at low frequencies or dc conditions. Activated surface transport will almost always exist in parallel with free molecular flow transport, and the process of alkali atom adsorption/desorption from the electrode surface will invariably be part of the transport process, and possibly a dominant part in some cases. Little can be learned about the detailed mass transport process from the ac impedance or current voltage curves of an electrode at one set of operating parameters, because the transport process includes a number of important physical parameters that are not all uniquely determined by one experiment. The temperature dependence of diffusion coefficient of the alkali metal through the electrode in several cases provides an activation energy and …
Date: July 1, 1992
Creator: Williams, R. M.; Jeffries-Nakamura, B.; Ryan, M. A.; Underwood, M. L.; O`Connor, D. & Kikkert, S.
Object Type: Article
System: The UNT Digital Library
Activated transport in AMTEC electrodes (open access)

Activated transport in AMTEC electrodes

Transport of alkali metal atoms through porous cathodes of alkali metal thermal-to-electric converter (AMTEC) cells is responsible for significant, reducible losses in the electrical performance of these cells. Experimental evidence for activated transport of metal atoms at grain surfaces and boundaries within some AMTEC electrodes has been derived from temperature dependent studies as well as from analysis of the detailed frequency dependence of ac impedance results for other electrodes, including thin, mature molybdenum electrodes which exhibit transport dominated by free molecular flow of sodium gas at low frequencies or dc conditions. Activated surface transport will almost always exist in parallel with free molecular flow transport, and the process of alkali atom adsorption/desorption from the electrode surface will invariably be part of the transport process, and possibly a dominant part in some cases. Little can be learned about the detailed mass transport process from the ac impedance or current voltage curves of an electrode at one set of operating parameters, because the transport process includes a number of important physical parameters that are not all uniquely determined by one experiment. The temperature dependence of diffusion coefficient of the alkali metal through the electrode in several cases provides an activation energy and …
Date: January 1, 1992
Creator: Williams, R.M.; Jeffries-Nakamura, B.; Ryan, M.A.; Underwood, M.L.; O'Connor, D. & Kikkert, S.
Object Type: Article
System: The UNT Digital Library
The Activities of Disaster Relief Organizations During the Permanent Housing Phase of Recovery: a Case Study Analysis (open access)

The Activities of Disaster Relief Organizations During the Permanent Housing Phase of Recovery: a Case Study Analysis

This study investigates the recovery efforts provided for low income and ethnic minority populations by organizations during the permanent housing phase of recovery in Watsonville, California, following the Loma Prieta earthquake of October 17, 1989. The case study format is used to discover what activities were performed and why each organization chose to perform them. Dynes and Quarantelli's (1968) typology of organization is used to explain how and why established, expanding, extending and emergent organizations participated in the recovery efforts. The findings indicate that the type of organization dictated the kind of tasks each organization performed. Organizations maintained activities during recovery for which they had experience, expertise and proficiency.
Date: August 1992
Creator: Ephraim, Melinda M. H.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
[Black and Gay and Lesbian received grant and announces 1993 conference] (open access)

[Black and Gay and Lesbian received grant and announces 1993 conference]

A press release announcing the Black Gay and Lesbian Leadership Forum were awarded a grant from the Center for Disease Control to fund the 5th annual AIDS Institute at the National Black Gay and Lesbian Conference.
Date: October 17, 1992
Creator: Chapple, Reginald
Object Type: Text
System: The UNT Digital Library
[Clipping: Pushing The Limits] (open access)

[Clipping: Pushing The Limits]

Newspaper clipping of an article about Alma Jeschien, a WASP member, working as an air-show pilot. The articles includes personal stories from her experiences a pilot, and a photograph of Jeschien standing next to a small propeller on a tarmac. On the back of the clipping are a few articles, letters to the editor, and a multi-panel political cartoon.
Date: September 8, 1992
Creator: Pisano, Marina
Object Type: Clipping
System: The Portal to Texas History
[Clipping: Pushing The Limits] (open access)

[Clipping: Pushing The Limits]

Newspaper clipping of an article about Alma Jeschien, a WASP member, working as an air-show pilot. The articles includes personal stories from her experiences a pilot, and a photograph of Jeschien standing next to a small propeller on a tarmac. On the back of the clipping are a few articles, letters to the editor, and a multi-panel political cartoon.
Date: September 8, 1992
Creator: Pisano, Marina
Object Type: Clipping
System: The Portal to Texas History
Contingent post-closure plan, hazardous waste management units at selected maintenance facilities, US Army National Training Center, Fort Irwin, California (open access)

Contingent post-closure plan, hazardous waste management units at selected maintenance facilities, US Army National Training Center, Fort Irwin, California

The National Training Center (NTC) at Fort Irwin, California, is a US Army training installation that provides tactical experience for battalion/task forces and squadrons in a mid- to high-intensity combat scenario. Through joint exercises with US Air Force and other services, the NTC also provides a data source for improvements of training doctrines, organization, and equipment. To meet the training and operational needs of the NTC, several maintenance facilities provide general and direct support for mechanical devices, equipment, and vehicles. Maintenance products used at these facilities include fuels, petroleum-based oils, lubricating grease, various degreasing solvents, antifreeze (ethylene glycol), transmission fluid, brake fluid, and hydraulic oil. Used or spent petroleum-based products generated at the maintenance facilities are temporarily accumulated in underground storage tanks (USTs), collected by the NTC hazardous waste management contractor (HAZCO), and stored at the Petroleum, Oil, and Lubricant (POL) Storage Facility, Building 630, until shipped off site to be recovered, reused, and/or reclaimed. Spent degreasing solvents and other hazardous wastes are containerized and stored on-base for up to 90 days at the NTC`s Hazardous Waste Storage Facility, Building 703. The US Environmental Protection Agency (EPA) performed an inspection and reviewed the hazardous waste management operations of the NTC. …
Date: January 1, 1992
Creator: unknown
Object Type: Report
System: The UNT Digital Library
[Counter Colón-ialismo, September 27, 1991-May 23, 1993] (open access)

[Counter Colón-ialismo, September 27, 1991-May 23, 1993]

Catalog for the "Counter Colón-ialismo" exhibit including biographies of participating artists, descriptions of the art pieces in the exhibit, and other information about the series.
Date: 1992
Creator: Mexic-Arte Museum (Austin, Tex.)
Object Type: Book
System: The Portal to Texas History
Direct Conversion Technology (open access)

Direct Conversion Technology

The overall objective of the Direct Conversion Technology task is to develop an experimentally verified technology base for promising direct conversion systems that have potential application for energy conservation in the end-use sectors. Initially, two systems were selected for exploratory research and advanced development. These are Alkali Metal Thermal-to-Electric Converter (AMTEC) and Two-Phase Liquid Metal MD Generator (LMMHD). This report describes progress that has been made during the first six months of 1992 on research activities associated with these two systems. (GHH)
Date: July 1, 1992
Creator: Back, L.H.; Fabris, G. & Ryan, M.A.
Object Type: Report
System: The UNT Digital Library
Direct conversion technology (open access)

Direct conversion technology

The overall objective of the Direct Conversion Technology task is to develop an experimentally verified technology base for promising direct conversion systems that have potential application for energy conservation in the end-use sectors. This report contains progress of research on the Alkali Metal Thermal-to-Electric Converter (AMTEC) and on the Two-Phase Liquid-Metal MHD Electrical Generator (LMMHD) for the period January 1, 1991 through December 31, 1991. Research on AMTEC and on LMMHD was initiated during October 1987. Reports prepared on previous occasions (Refs. 1--5) contain descriptive and performance discussions of the following direct conversion concepts: thermoelectric, pyroelectric, thermionic, thermophotovoltaic, thermoacoustic, thermomagnetic, thermoelastic (Nitionol heat engine); and also, more complete descriptive discussions of AMTEC and LMMHD systems.
Date: January 7, 1992
Creator: Massier, P.F.; Back, L.H.; Ryan, M.A. & Fabris, G.
Object Type: Report
System: The UNT Digital Library
Direct conversion technology. Annual summary report CY 1991, January 1, 1991--December 31, 1991 (open access)

Direct conversion technology. Annual summary report CY 1991, January 1, 1991--December 31, 1991

The overall objective of the Direct Conversion Technology task is to develop an experimentally verified technology base for promising direct conversion systems that have potential application for energy conservation in the end-use sectors. This report contains progress of research on the Alkali Metal Thermal-to-Electric Converter (AMTEC) and on the Two-Phase Liquid-Metal MHD Electrical Generator (LMMHD) for the period January 1, 1991 through December 31, 1991. Research on AMTEC and on LMMHD was initiated during October 1987. Reports prepared on previous occasions (Refs. 1--5) contain descriptive and performance discussions of the following direct conversion concepts: thermoelectric, pyroelectric, thermionic, thermophotovoltaic, thermoacoustic, thermomagnetic, thermoelastic (Nitionol heat engine); and also, more complete descriptive discussions of AMTEC and LMMHD systems.
Date: January 7, 1992
Creator: Massier, P. F.; Back, L. H.; Ryan, M. A. & Fabris, G.
Object Type: Report
System: The UNT Digital Library
Direct Conversion Technology. Progress report, January 1, 1992--June 30, 1992 (open access)

Direct Conversion Technology. Progress report, January 1, 1992--June 30, 1992

The overall objective of the Direct Conversion Technology task is to develop an experimentally verified technology base for promising direct conversion systems that have potential application for energy conservation in the end-use sectors. Initially, two systems were selected for exploratory research and advanced development. These are Alkali Metal Thermal-to-Electric Converter (AMTEC) and Two-Phase Liquid Metal MD Generator (LMMHD). This report describes progress that has been made during the first six months of 1992 on research activities associated with these two systems. (GHH)
Date: July 1, 1992
Creator: Back, L. H.; Fabris, G. & Ryan, M. A.
Object Type: Report
System: The UNT Digital Library
Efficiency of an AMTEC recirculating test cell, experiments and projections (open access)

Efficiency of an AMTEC recirculating test cell, experiments and projections

The alkali metal thermal to electric converter (AMTEC) is an electrochemical device for the direct conversion of heat to electrical energy with efficiencies potentially near Carnot. The future usefulness of AMTEC for space power conversion depends on the efficiency of the devices. Systems studies have projected from 15% to 35% thermal to electric conversion efficiencies, and one experiment has demonstrated 19% efficiency for a short period of time. Recent experiments in a recirculating test cell (RTC) have demonstrated sustained conversion efficiencies as high as 10.2% early in cell life and 9.7% after maturity. Extensive thermal and electrochemical analysis of the cell during several experiments demonstrated that the efficiency could be improved in two ways. First, the electrode performance could be improved. The electrode for these tests operated at about one third the power density of state of the art electrodes. The low power density was caused by a combination of high series resistance and high mass flow resistance. Reducing these resistances could improve the efficiency to greater than 10%. Second, the cell thermal performance could be improved. Efficiencies greater than 14% could be realized through reducing the radiative thermal loss. Further improvements to the efficiency range predicted by systems studies …
Date: May 1, 1992
Creator: Underwood, M. L.; O`Connor, D.; Williams, R. M.; Jeffries-Nakamura, B. & Ryan, M. A.
Object Type: Article
System: The UNT Digital Library
Electrical characterization of electrophoretically coated aluminum samples for photovoltaic concentrator application (open access)

Electrical characterization of electrophoretically coated aluminum samples for photovoltaic concentrator application

The practicality of using a thin-film styrene/acrylate copolymer electrophoretic coating to isolate concentrator cells electrically from their surroundings in a photovoltaic concentrator module is assessed. Only the electrical isolation problem was investigated. The approach was to subject various types of EP-coated aluminum specimens to electrical stress testing and to aging tests while monitoring coating electrical resistivity properties. It was determined that, in general, longer processing times--i.e., thicker electrophoretic layers--resulted in better voltage-withstand properties. In particular, a two-minute processing time seemed sufficient to provide the electrical isolation required in photovoltaic concentrator application applications. Even though electrophoretic coatings did not seem to fill voids in porous-anodized aluminum substrates, breakdown voltages generally exceeded hi-pot pass-fail voltage levels with a comfortable margin. 6 refs, 11 figs, 5 tabs.
Date: October 1, 1992
Creator: Sugimura, R. S.; Mon, G. R. & Ross, R. G. Jr.
Object Type: Report
System: The UNT Digital Library
Electron cyclotron resonance deposition of amorphous silicon alloy films and devices (open access)

Electron cyclotron resonance deposition of amorphous silicon alloy films and devices

This report describes work to develop a state-of-the-art electron cyclotron resonance (ECR) plasma-enhanced chemical vapor deposition (PECVD) system. The objective was to understand the deposition processes of amorphous silicon (a-Si:H) and related alloys, with a best-effort improvement of optoelectronic material properties and best-effort stabilization of solar cell performance. ECR growth parameters were systematically and extensively investigated; materials characterization included constant photocurrent measurement (CPM), junction capacitance, drive-level capacitance profiling (DLCP), optical transmission, light and dark photoconductivity, and small-angle X-ray scattering (SAXS). Conventional ECR-deposited a-Si:H was compared to a new form, a-Si:(Xe, H), in which xenon gas was added to the ECR plasma. a-Si:(Xe,H) possessed low, stable dark conductivities and high photosensitivites. Light-soaking revealed photodegradation rates about 35% lower than those of comparable radio frequency (rf)-deposited material. ECR-deposited p-type a SiC:H and intrinsic a-Si:H films underwent evaluation as components of p-i-n solar cells with standard rf films for the remaining layers.
Date: October 1, 1992
Creator: Shing, Y. H. (Jet Propulsion Lab., Pasadena, CA (United States))
Object Type: Report
System: The UNT Digital Library
Electron cyclotron resonance deposition of amorphous silicon alloy films and devices. Final subcontract report, 1 April 1991--31 March 1992 (open access)

Electron cyclotron resonance deposition of amorphous silicon alloy films and devices. Final subcontract report, 1 April 1991--31 March 1992

This report describes work to develop a state-of-the-art electron cyclotron resonance (ECR) plasma-enhanced chemical vapor deposition (PECVD) system. The objective was to understand the deposition processes of amorphous silicon (a-Si:H) and related alloys, with a best-effort improvement of optoelectronic material properties and best-effort stabilization of solar cell performance. ECR growth parameters were systematically and extensively investigated; materials characterization included constant photocurrent measurement (CPM), junction capacitance, drive-level capacitance profiling (DLCP), optical transmission, light and dark photoconductivity, and small-angle X-ray scattering (SAXS). Conventional ECR-deposited a-Si:H was compared to a new form, a-Si:(Xe, H), in which xenon gas was added to the ECR plasma. a-Si:(Xe,H) possessed low, stable dark conductivities and high photosensitivites. Light-soaking revealed photodegradation rates about 35% lower than those of comparable radio frequency (rf)-deposited material. ECR-deposited p-type a SiC:H and intrinsic a-Si:H films underwent evaluation as components of p-i-n solar cells with standard rf films for the remaining layers.
Date: October 1, 1992
Creator: Shing, Y. H.
Object Type: Report
System: The UNT Digital Library
[Flirting With Power: Irvine Rally, 1 of 2] captions transcript

[Flirting With Power: Irvine Rally, 1 of 2]

Video footage from the Jo Streit Film Footage Collection consisting of original Betacam footage from filmmaker Jo Streit's documentary "Flirting with Power." Footage includes interviews with rally attendees, Perot delivering a speech, and shots of the watching crowd.
Date: June 22, 1992
Creator: Streit, Jo
Object Type: Video
System: The UNT Digital Library
[Flirting With Power: Irvine Rally, 2 of 2] captions transcript

[Flirting With Power: Irvine Rally, 2 of 2]

Video footage from the Jo Streit Film Footage Collection consisting of original Betacam footage from filmmaker Jo Streit's documentary "Flirting with Power." Footage consists of interviews with rally attendees.
Date: June 22, 1992
Creator: Streit, Jo
Object Type: Video
System: The UNT Digital Library
[Flirting With Power: Long Beach, California Rally, 1 of 2] captions transcript

[Flirting With Power: Long Beach, California Rally, 1 of 2]

Video footage from the Jo Streit Film Footage Collection consisting of original Betacam footage from filmmaker Jo Streit's documentary "Flirting with Power." The footage covers musical performances followed by speeches from Orson Swindle, Admiral James Bond "Jim" Stockdale, and Ross Perot.
Date: November 1, 1992
Creator: Streit, Jo
Object Type: Video
System: The UNT Digital Library
[Flirting With Power: Long Beach, California Rally, 2 of 2] captions transcript

[Flirting With Power: Long Beach, California Rally, 2 of 2]

Video footage from the Jo Streit Film Footage Collection consisting of original Betacam footage from filmmaker Jo Streit's documentary "Flirting with Power." The footage covers Ross Perot speaking before a large crowd while a row of people, including Orson Swindle and Admiral James Bond "Jim" Stockdale, sit behind him.
Date: November 1, 1992
Creator: Streit, Jo
Object Type: Video
System: The UNT Digital Library
Funeral Program for Mamie Louise Gant (open access)

Funeral Program for Mamie Louise Gant

Funeral Program for Mamie Louise Gant
Date: January 17, 1992
Creator: unknown
Object Type: Pamphlet
System: The Gateway to Oklahoma History
GDFW This Week, Volume 6, Number 14, April 10, 1992 (open access)

GDFW This Week, Volume 6, Number 14, April 10, 1992

Weekly newsletter published for employees of the Fort Worth Division of General Dynamics containing work-related information, updates about employees, and other news.
Date: April 10, 1992
Creator: General Dynamics Corporation. Fort Worth Division.
Object Type: Journal/Magazine/Newsletter
System: The Portal to Texas History

[Group Portrait for Dorothy Washington Reception]

Photograph of several men and women gathered together for a group picture. They are wearing formal attire and stand in two rows on the stone and brick floor of a pool and hot tub that is directly in front of them. Accompanying information indicates they were gathered for a reception honoring Link member Dorothy Washington. Presumably, she is somewhere in the group, but she has not been identified.
Date: January 1992
Creator: Links, Inc. San Antonio Chapter.
Object Type: Photograph
System: The Portal to Texas History
[Letter from Gail Unzelman to Roy Renfro, April 10, 1992] (open access)

[Letter from Gail Unzelman to Roy Renfro, April 10, 1992]

Letter from Gail Unzelman to Roy Renfro discussing the historic relationship between T. V. Munson and George Husmann and some papers related to T. V. Munson that Renfro may find interesting or relevant.
Date: April 10, 1992
Creator: Unzelman, Gail
Object Type: Letter
System: The Portal to Texas History