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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: January 1, 1992
Creator: Williams, R.M.; Jeffries-Nakamura, B.; Ryan, M.A.; Underwood, M.L.; O'Connor, D. & Kikkert, S.
System: The UNT Digital Library
Advances in high temperature components for AMTEC (alkali metal thermal-to-electric converter) (open access)

Advances in high temperature components for AMTEC (alkali metal thermal-to-electric converter)

Long lifetimes are required for AMTEC (or sodium heat engine) components for aerospace and terrestrial applications, and the high heat input temperature as well as the alkali metal liquid and vapor environment places unusual demands on the materials used to construct AMTEC devices. In addition, it is important to maximize device efficiency and power density, while maintaining a long life capability. In addition to the electrode, which must provide both efficient electrode kinetics, transport of the alkali metal, and low electrical resistance, other high temperature components of the cell face equally demanding requirements. The beta{double prime} alumina solid electrolyte (BASE), the seal between the BASE ceramic and its metallic transition to the hot alkali metal (liquid or vapor) source, and metallic components of the device are exposed to hot liquid alkali metal. Modification of AMTEC components may also be useful in optimizing the device for particular operating conditions. In particular, a potassium AMTEC may be expected to operate more efficiently at lower temperatures.
Date: January 1, 1991
Creator: Williams, R.M.; Jeffries-Nakamura, B.; Underwood, M.L.; Ryan, M.A.; O'Connor, D. & Kikkert, S.
System: The UNT Digital Library
[After a Fashion, January 2005] (open access)

[After a Fashion, January 2005]

Article about the Golden Globe Awards, Erin Elmore, and the author's receipt of the Media Correspondent Award from Philanthropy World magazine.
Date: January 2005
Creator: Moser, Stephen MacMillan
System: The UNT Digital Library
Article regarding Zella Patterson's appearance in personalities of the South (open access)

Article regarding Zella Patterson's appearance in personalities of the South

Article regarding news from Langston University and announcing the inclusion of Zella Patterson in the list of personalities of the South.
Date: January 10, 1971
Creator: unknown
System: The Gateway to Oklahoma History
Brilliant People (open access)

Brilliant People

Article about Brilliant Magazine's fifth anniversary celebration held at Pangaea in Austin, Texas.
Date: January 2008
Creator: Ball, Linda
System: The UNT Digital Library
Brilliant's 5th (open access)

Brilliant's 5th

Article about Brilliant Magazine's 5th anniversary celebration held at Pangaea in Austin, Texas, on January 24, 2008.
Date: January 25, 2008
Creator: unknown
System: The UNT Digital Library
Characterization of Fly Ash From Coal Combustion (open access)

Characterization of Fly Ash From Coal Combustion

Fly ash derived from coal combustion contains predominantly spherical particles which consist of an insoluble aluminosilicate glass containing several mineral impurities. An outer layer, 50 to 300 A thick, is rich in many potentially toxic trace elements in the form of simple and complex sulfates. This layer, which is soluble in water, contains essentially all of the particulate sulfur present in fly ash in the form of sulfate. The actual mechanism(s) of formation of particulate sulfate salts are ill-defined but probably involve adsorption of condensation of gaseous sulfur species onto fly ash surfaces within the power plant stack system.
Date: January 1, 1978
Creator: Natusch, D. F.S.
System: The UNT Digital Library
Clay mineralogy and depositional history of the Frio Formation in two geopressured wells, Brazoria County, Texas (open access)

Clay mineralogy and depositional history of the Frio Formation in two geopressured wells, Brazoria County, Texas

Twenty-three shale samples ranging in depth from 5194 ft to 13,246 ft from Gulf Oil Corporation No. 2 Texas State Lease 53034 well and 33 shale samples ranging in depth from 2185 ft to 15,592 ft from General Crude Oil Company/Department of Energy No. 1 Pleasant Bayou well were examined by x-ray techniques to determine the mineralogy of the geopressured zone in the Brazoria Fairway. Both wells have similar weight-percent trends with depth for a portion of the mineralogy. Calcite decreases, and plagioclase, quartz and total clay increase slightly. Within the clays, illite in mixed-layer illite/smectite (I/S) increases and smectite in mixed-layer I/S decreases. Four minerals have distinctly different trends with depth for each well. In the No. 2 Texas State Lease 53034 well, potassium feldspar and mixed-layer I/S decrease, kaolinite increases, and discrete illite is constant. In the No. 1 Pleasant Bayou well, potassium feldspar and kaolinite are constant, mixed-layer I/S increases, and discrete illite decreases.
Date: January 1, 1982
Creator: Freed, R.L.
System: The UNT Digital Library
Colorado State University Solar Heated and Cooled House (open access)

Colorado State University Solar Heated and Cooled House

None
Date: January 1, 1974
Creator: Lof, G.O.G.
System: The UNT Digital Library
Comparative Performance of Two Types of Evacuated Tube Solar Collectors in a Residential Heating and Cooling System - The Progress Report (open access)

Comparative Performance of Two Types of Evacuated Tube Solar Collectors in a Residential Heating and Cooling System - The Progress Report

Two types of evacuated tube solar collectors have been operated in space heating, cooling and domestic hot water heating systems in Colorado State University Solar House I. An experimental collector from Corning Glass Works supplied heat to the system from January 1977 through February 1978, and an experimental collector from Philips Research Laboratory, Aachen, which is currently in use, has been operating since August 1978. A flat absorber plate inside a single-walled glass tube is used in the Corning design, whereas heat is conducted through a single glass wall to an external heat exchanger plate in the Philips collector. In comparison with conventional flat-plate collectors, both types show reduced heat losses and improved efficiency. For space heating and hot water supply in winter, the solar delivery efficiency of the Corning collector ranged from 49% to 60% of the incident solar energy. The portion of the space heating and domestic hot water load carried by solar energy through fall and winter ranged from 50% to 74%, with a four-month contribution of 61% of the total requirements. Data on the Philips collector are currently being analyzed.
Date: January 1, 1979
Creator: Conway, T. M.; Duff, W. S.; Loef, G. O. G. & Pratt, R. G.
System: The UNT Digital Library
Comparison of the Response of a Nai Scintillation Crystal With a Pressurized Ionization Chamber as a Function of Altitude, Radiation Level and RA-226 Concentration (open access)

Comparison of the Response of a Nai Scintillation Crystal With a Pressurized Ionization Chamber as a Function of Altitude, Radiation Level and RA-226 Concentration

The Grand Junction Uranium Mill Tailings Remedial Action-Radiological Survey Activities Group (UMTRA-RASA) program employs a screening method in which external exposure rates are used to determine if a property contaminated with uranium mill tailings is eligible for remedial action. Portable NaI detectors are used by survey technicians to locate contaminated areas and determine exposure rates. The exposure rate is calculated using a regression equation derived from paired measurements made with a pressurized ionization chamber (PIC) and a NaI detector. During July of 1985 extensive measurements were taken using a PIC and a NaI scintillator with both analogue and digital readout for a wide range of exposure rates and at a variety of elevations. The surface soil was sampled at most of these locations and analyzed for /sup 226/Ra. The response of the NaI detectors was shown to be highly correlated to radiation level but not to /sup 226/Ra concentration or elevation.
Date: January 1, 1986
Creator: Provencher, R.; Smith, G.; Borak, T.B. & Kearney, P.
System: The UNT Digital Library
Controlling Gully Erosion with Earth Dams in North-Central Texas (open access)

Controlling Gully Erosion with Earth Dams in North-Central Texas

This article describes the use of earth dams for controlling gully erosion in part of the Eastern Cross Timbers of North-Central Texas.
Date: January 2001
Creator: Hudak, Paul F. & Chadbourne, John
System: The UNT Digital Library
Deep crustal sediment study: Widespread Precambrian layered rocks (Sedimentary) beneath the US midcontinent (open access)

Deep crustal sediment study: Widespread Precambrian layered rocks (Sedimentary) beneath the US midcontinent

A thick sequence of layered rocks occurs beneath the Phanerozoic platform strata which blanket the US midcontinent. Observed on COCORP deep reflection data in southern Illinois and Indiana and in SW Oklahoma and adjacent Texas, this sequence is locally 1--3 times as thick as the overlying Paleozoic cover, but the origin of this sequence, its ultimate lateral extent, and resource potential are unknown. The objective of this project is to seek and reprocess seismic reflection data provided by industry from the US midcontinent and together with the COCORP deep reflection data and information from the scattered basement-penetrating drill holes, to begin to constrain the distribution, origin and evolution of this enigmatic layered sequence, particularly to evaluate if sedimentary material may be an important constituent (i.e., deep gas potential).
Date: January 1, 1992
Creator: Hauser, E. C.
System: The UNT Digital Library
Dual arm master controller concept (open access)

Dual arm master controller concept

The Advanced Servomanipulator (ASM) slave was designed with an anthropomorphic stance, gear/torque tube power drives, and modular construction. These features resulted in increased inertia, friction, and backlash relative to tape-driven manipulators. Studies were performed which addressed the human factors design and performance trade-offs associated with the corresponding master controller best suited for the ASM. The results of these studies, as well as the conceptual design of the dual arm master controller, are presented. 6 references, 3 figures.
Date: January 1, 1984
Creator: Kuban, D.P. & Perkins, G.S.
System: The UNT Digital Library
Dual arm master controller development (open access)

Dual arm master controller development

The advanced servomanipulator (ASM) slave was designed with an anthropomorphic stance, gear/torque tube power drives, and modular construction. These features resulted in increased inertia, friction, and backlash relative to tape-driven manipulators. Studies were performed which addressed the human factors design and performance trade-offs associated with the corresponding master controller best suited for the ASM. The results of these studies, as well as the conceptual design of the dual arm master controller, are presented. This work was performed as part of the Consolidated Fuel Reprocessing Program at the Oak Ridge National Laboratory. 5 refs., 7 figs., 1 tab.
Date: January 1, 1985
Creator: Kuban, D. P. & Perkins, G. S.
System: The UNT Digital Library
Elements of high constructive deltaic sedimentation, lower Frio Formation, Brazoria County, Texas (open access)

Elements of high constructive deltaic sedimentation, lower Frio Formation, Brazoria County, Texas

The lower Frio Formation in eastern Brazoria County, upper Texas Gulf Coast, was deposited in a high constructive deltaic environment in the Houston delta system. Constructive elements of the stacked, elongate to lobate deltas that were intersected in core are storm induced delta front splays, delta front slump deposits, and distributary mouth bar, distributary channel and delta plain assemblages. Reworked and winnowed abandonment facies that are volumetrically insignificant relative to constructive elements are subdivided into a crossbedded shoreface-foreshore subfacies and a fine grained cyclic sequence of storm deposits on the lower shoreface that represent a distal abandonment subfacies. Micropaleontological evidence indicates that deposition of constructive and abandonment facies took place in water depths of less than 120 feet.
Date: January 1, 1982
Creator: Tyler, N. & Han, J. H.
System: The UNT Digital Library
Experimental evaluation of a fixed collector employing vee-trough concentrator and vacuum tube receivers (open access)

Experimental evaluation of a fixed collector employing vee-trough concentrator and vacuum tube receivers

A test bed for experimental evaluation of a fixed solar collector which combines an evacuated glass tube solar receiver with a flat plate/black chrome plated copper absorber and an asymmetric veetrough concentrator was designed and constructed. Earlier predictions of thermal performance were compared with test data acquired for a bare vacuum tube receiver; and receiver tubes with Alzak aluminum, aluminized FEP Teflon film laminated sheet metal and second surface ordinary mirror reflectors. Test results and system economics as well as objectives of an ongoing program to obtain long-term performance data are discussed.
Date: January 1, 1977
Creator: Selcuk, M. K.
System: The UNT Digital Library
External flow radiators for reduced space powerplant temperatures. Technical information report (open access)

External flow radiators for reduced space powerplant temperatures. Technical information report

Nuclear space powerplants can operate at temperatures below 900 K and use stainless steel construction without a weight penalty if new radiator concepts can achieve radiator weights of 1-3 kg/m{sup 2}. Conventional tube-and-fin radiators weight about 10 kg/m{sup 2} because of heavy tube walls to prevent meteroid puncture. Radiator designs that do not require meteroid protection are possible; they operate with fluids of low vapor pressure that can be exposed directly to space in external-flow radiators. An example is the {open_quotes}rotating disk radiator{close_quotes} in which centrifugal force drives a liquid film radially outward across a thin rotating metal disk; meteroid punctures cause no loss of fluid other than from evaporation, which can be small. An even lighter concept is the liquid drop radiator in which heat is radiated directly from moving liquid drops. Such radiator concepts look practical, and they may be much easier to develop than the high-temperature, refractory-metal power systems necessitated by conventional radiators.
Date: January 1, 1984
Creator: Elliott, D. G.
System: The UNT Digital Library
[Fort Worth Star-Telegram Arts & Entertainment, January 30, 1995] (open access)

[Fort Worth Star-Telegram Arts & Entertainment, January 30, 1995]

An article written by Janet Tyson for the Arts & Entertainment section of the Fort Worth Star-Telegram titled 'Thumbnail Sketch'. The piece is a snapshot of who Dr. R. William McCarter is with direct quotes from him.
Date: January 30, 1995
Creator: Tyson, Janet
System: The UNT Digital Library
[Fox 4 KDFW Good Day, 2004-01-01] (open access)

[Fox 4 KDFW Good Day, 2004-01-01]

Article about Evel Knievel's appearance at Will Rogers Coliseum, Franklin Covey's advice on New Year's resolutions, the launching of Brilliant Magazine, and a recipe by Tim Love.
Date: January 1, 2004
Creator: Fox 4 KDFW
System: The UNT Digital Library
General Circulation of the Atmosphere and Weather in the Mediterranean (open access)

General Circulation of the Atmosphere and Weather in the Mediterranean

The occurrence of mistral winds in the Mediterranean shows a correlation with blocking activity over the eastern Atlantic. Apparently for this reason periods with a ''midwinter dip'' in the zonal available potential energy of the northern hemisphere are favored by mistral occurrence. There also is a tendency for a 22- to 26-day cycle to appear in pressure gradients at the 500- and 100-mb surfaces along the southern coast of France. Such pressure gradients, if they exceed a certain magnitude, are indicative of mistral episodes.
Date: January 1, 1976
Creator: Reiter, Elmar R.
System: The UNT Digital Library
Generation of a strong core-centering force in a submillimeter compound droplet system (open access)

Generation of a strong core-centering force in a submillimeter compound droplet system

By amplitude-modulating the driving voltage of an acoustic levitating apparatus, a strong core-centering force can be generated in a submillimeter compound droplet system suspended by the radiation pressure in a gaseous medium. Depending on the acoustic characteristics of the droplet system, it has been found that the technique can be utilized advantageously in the multiple-layer coating of an inertial-confinement-fusion pellet.
Date: January 1, 1981
Creator: Lee, M. C.; Feng, I.; Elleman, D. D.; Wang, T. G. & Young, A. T.
System: The UNT Digital Library
Guides to Inventory Policy: I. Functions and Lot Size (open access)

Guides to Inventory Policy: I. Functions and Lot Size

Article reprinted from The Harvard Business Review discussing methods of inventory control and production planning.
Date: 1956-01/1956-02
Creator: Magee, John F.
System: The Portal to Texas History
Habitat Quantity of Red-Cockaded Woodpecker Picoides Borealis (Aves: Piciformes: Picidae) in its Former Historic Landscape Near the Big Thicket Naitonal Preserve, Texas, USA (open access)

Habitat Quantity of Red-Cockaded Woodpecker Picoides Borealis (Aves: Piciformes: Picidae) in its Former Historic Landscape Near the Big Thicket Naitonal Preserve, Texas, USA

This article quantifies pine-forested habitat suitable for Red-cockaded Woodpecker in the former historic range of the species to assess the potential for possible re-colonization.
Date: January 26, 2016
Creator: Thapa, Vivek & Acevedo, Miguel F.
System: The UNT Digital Library