Resource Type

From Tragedy to Triumph: Rebuilding Greensburg, Kansas To Be a 100% Renewable Energy City; Preprint (open access)

From Tragedy to Triumph: Rebuilding Greensburg, Kansas To Be a 100% Renewable Energy City; Preprint

On May 4, 2007, Greensburg, Kansas, was hit by a 1.7-mile wide tornado with 200 mph-plus wind speeds. This tornado destroyed or severely damaged 90% of Greensburg?s structures. We discuss the progress made in rebuilding Greensburg, with a focus on the built environment and on meeting Greensburg?s goal of 100% renewable energy, 100% of the time. We also discuss key disaster recovery efforts that enabled Greensburg to reach this goal. Key strategies included a Sustainable Comprehensive Master Plan, an ordinance resolving that city-owned buildings achieve LEED Platinum and 42% energy savings, a strong focus on rebuilding 'right' with an integrated design process, attracting significant and sustained technical experts and national media attention, and linking renewable and energy efficiency technologies to business development. After three years, more than half the homes that have been rebuilt are rated at an average of 40% energy savings. All significant commercial buildings, including the school, hospital, banks, courthouse, and retail buildings, have been rebuilt to LEED Gold and Platinum standards and exceed 40% savings, with many exceeding 50% savings. Greensburg recently constructed a 12.5-MW community wind farm to provide all the remaining energy needed for its energy-efficient buildings and homes.
Date: August 1, 2010
Creator: Pless, S.; Billman, L. & Wallach, D.
System: The UNT Digital Library
Reconstruction of False Spring Occurrence Over the Southeastern U.S., 1901–2007: Increasing Risk of Spring Freeze Damage? (open access)

Reconstruction of False Spring Occurrence Over the Southeastern U.S., 1901–2007: Increasing Risk of Spring Freeze Damage?

Near-record warmth over much of the United States during March 2007 promoted early growth of crops and vegetation. A widespread arctic air outbreak followed in early April, resulting in extensive agricultural losses over the southeastern U.S. This “false spring” event also resulted in widespread damage to newly grown tissues of native deciduous forest species, shown by previous researchers to have affected the terrestrial carbon cycle. The current study reconstructed the historical occurrence of false springs for the southeastern U.S. (32–39 °N; 75–98 °W) from 1901–2007 using daily maximum and minimum temperature records from 176 stations in the Global Historical Climatology Network database, and Enhanced Vegetation Index (EVI) data derived from Moderate Resolution Imaging Spectroradiometer (MODIS) satellite observations. A false spring index examined the relative timing of the start of the growing season (SGS), or leaf-out, to the timing of a potentially damaging last hard freeze (≤ -2.2 °C). SGS was modeled for the domain by combining EVI data with ground-based temperature “degree-day” calculations refl ecting the rate of springtime warming. No significant area-wide, long-term SGS trend was found (0.2 days later/decade; p = 0.3). However, the timing of the last hard freeze did occur significantly later (>1 day/decade; p < …
Date: January 1, 2009
Creator: Marino, Garrett P. & Kaiser, Dale P.
System: The UNT Digital Library
Borehole Seismic Monitoring of Injected CO2 at the Frio Site (open access)

Borehole Seismic Monitoring of Injected CO2 at the Frio Site

As part of a small scale sequestration test (about 1500 tonsof CO2) in a saline aquifer, time-lapse borehole seismic surveys wereconducted to aid in characterization of subsurface CO2 distribution andmaterial property changes induced by the injected CO2. A VSP surveydemonstrated a large increase (about 75 percent) in seismic reflectivitydue to CO2 injection and allowed estimation of the spatial extent of CO2induced changes. A crosswell survey imaged a large seismic velocitydecrease (up to 500 m/s) within the injection interval and provided ahigh resolution image of this velocity change which maps the subsurfacedistribution of CO2 between two wells. Numerical modeling of the seismicresponse uses the crosswell measurements to show that this small CO2volume causes a large response in the seismic reflectivity. This resultdemonstrates that seismic detection of small CO2 volumes in salineaquifers is feasible and realistic.
Date: April 21, 2006
Creator: Daley, Thomas M.; Myer, Larry R.; Hoversten, G.M.; Peterson, JohnE. & Korneev, Valeri A.
System: The UNT Digital Library
High Field Magnet R&D in the USA (open access)

High Field Magnet R&D in the USA

Accelerator magnet technology is currently dominated by the use of NbTi superconductor. New and more demanding applications for superconducting accelerator magnets require the use of alternative materials. Several programs in the US are taking advantage of recent improvements in Nb{sub 3}Sn to develop high field magnets for new applications. Highlights and challenges of the US R and D program are presented along with the status of conductor development. In addition, a new R and D focus, the US LHC Accelerator Research Program, will be discussed.
Date: October 1, 2003
Creator: Gourlay, Stephen A.
System: The UNT Digital Library
Combined Geophysical Investigation Techniques to Identify Buried Waste in an Uncontrolled Landfill at the Paducah Gaseous Diffusion Plant, Kentucky (open access)

Combined Geophysical Investigation Techniques to Identify Buried Waste in an Uncontrolled Landfill at the Paducah Gaseous Diffusion Plant, Kentucky

The primary objective of the investigation was to confirm the presence and determine the location of a cache of 30 to 60 buried 55-gallon drums that were allegedly dumped along the course of the pre-existing, northsouth diversion ditch (NSDD) adjacent to permitted landfills at the Paducah Gaseous Diffusion Plant, Kentucky. The ditch had been rerouted and was being filled and re-graded at the time of the alleged dumping. Historic information and interviews with individuals associated with alleged dumping activities indicated that the drums were dumped prior to the addition of other fill materials. In addition, materials alleged to have been dumped in the ditch, such as buried roofing materials, roof flashing, metal pins, tar substances, fly ash, and concrete rubble complicated data interpretation. Some clean fill materials have been placed over the site and graded. This is an environment that is extremely complicated in terms of past waste dumping activities, construction practices and miscellaneous landfill operations. The combination of site knowledge gained from interviews and research of existing site maps, variable frequency EM data, classical total magnetic field data and optimized GPR lead to success where a simpler less focused approach by other investigators using EM-31 and EM-61 electromagnetic methods …
Date: February 27, 2003
Creator: Miller, Peter T. & Starmer, R. John
System: The UNT Digital Library
Remote Sensing Analysis of the Sierra Blanca (Faskin Ranch) Low-Level Radioactive Waste Disposal Site, Hudspeth County, Texas (open access)

Remote Sensing Analysis of the Sierra Blanca (Faskin Ranch) Low-Level Radioactive Waste Disposal Site, Hudspeth County, Texas

Remote sensing images provide useful physical information, revealing such features as geological structure, vegetation, drainage patterns, and variations in consolidated and unconsolidated lithologies. That technology has been applied to the failed Sierra Blanca (Faskin Ranch) shallow burial low-level radioactive waste disposal site selected by the Texas Low-Level Radioactive Waste Disposal Authority. It has been re-examined using data from LANDSAT satellite series. The comparison of the earlier LANDSAT V (5/20/86) (30-m resolution) with the later new, higher resolution ETM imagery (10/23/99) LANDSAT VII data (15-m resolution) clearly shows the superiority of the LANDSAT VII data. The search for surficial indications of evidence of fatal flaws at the Sierra Blanca site utilizing was not successful, as it had been in the case of the earlier remote sensing analysis of the failed Fort Hancock site utilizing LANDSAT V data. The authors conclude that the tectonic activity at the Sierra Blanca site is much less recent and active than in the previously studied Fort Hancock site. The Sierra Blanca site failed primarily on the further needed documentation concerning a subsurface fault underneath the site and environmental justice issues. The presence of this fault was not revealed using the newer LANDSAT VII data. Despite this …
Date: February 26, 2002
Creator: LeMone, D. V.; Dodge, R.; Xie, H.; Langford, R. P. & Keller, G. R.
System: The UNT Digital Library
Surface Remediation in the Aleutian Islands: A Case Study of Amchitka Island, Alaska (open access)

Surface Remediation in the Aleutian Islands: A Case Study of Amchitka Island, Alaska

Amchitka Island, Alaska, was at one time an integral player in the nation's defense program. Located in the North Pacific Ocean in the Aleutian Island archipelago, the island was intermittently inhabited by several key government agencies, including the U.S. Army, the U.S. Atomic Energy Commission (predecessor agency to the U.S. Department of Energy), and the U.S. Navy. Since 1993, the U.S. Department of Energy (DOE) has conducted extensive investigations on Amchitka to determine the nature and extent of contamination resulting from historic nuclear testing. The uninhabited island was the site of three high-yield nuclear tests from 1965 to 1971. These test locations are now part of the DOE's National Nuclear Security Administration Nevada Operations Office's Environmental Management Program. In the summer of 2001, the DOE launched a large-scale remediation effort on Amchitka to perform agreed-upon corrective actions to the surface of the island. Due to the lack of resources available on Amchitka and logistical difficulties with conducting work at such a remote location, the DOE partnered with the Navy and U.S. Army Corps of Engineers (USACE) to share certain specified costs and resources. Attempting to negotiate the partnerships while organizing and implementing the surface remediation on Amchitka proved to be …
Date: February 25, 2002
Creator: Giblin, M. O.; Stahl, D. C. & Bechtel, J. A.
System: The UNT Digital Library
Diurnal variation of NMHCs at a downtown site in Nashville: model and measurements. (open access)

Diurnal variation of NMHCs at a downtown site in Nashville: model and measurements.

None
Date: October 11, 2001
Creator: Kotamarthi, V. R.; Doskey, P. V.; Xu, Y.; Wesely, M. L.; Lonneman, W. & Olszyna, K.
System: The UNT Digital Library
A new lizard species in the genus Xantusia from Arizona (open access)

A new lizard species in the genus Xantusia from Arizona

None
Date: September 6, 2001
Creator: Papenfuss, Theodore J.; Macey, J. Robert & Schulte II, James A.
System: The UNT Digital Library
Evidence for an unsaturated-zone origin of secondary minerals in Yucca Mountain, Nevada (open access)

Evidence for an unsaturated-zone origin of secondary minerals in Yucca Mountain, Nevada

The unsaturated zone (UZ) in Miocene-age welded tuffs at Yucca Mountain, Nevada, is under consideration as a potential site for the construction of a high-level radioactive waste repository. Secondary calcite and silica minerals deposited on fractures and in cavities in the UZ tuffs are texturally, isotopically, and geochemically consistent with UZ deposition from meteoric water infiltrating at the surface and percolating through the UZ along fractures. Nonetheless, two-phase fluid inclusions with small and consistent vapor to liquid (V:L) ratios that yield consistent temperatures within samples and which range from about 35 to about 80 C between samples have led some to attribute these deposits to formation from upwelling hydrothermal waters. Geochronologic studies have shown that calcite and silica minerals began forming at least 10 Ma and continued to form into the Holocene. If their deposition were really from upwelling water flooding the UZ, it would draw into question the suitability of the site as a waste repository.
Date: April 29, 2001
Creator: Whelan, Joseph F.; Roedder, Edwin & Paces, James B.
System: The UNT Digital Library
Hydrologic characteristics of faults at Yucca Mountain, Nevada (open access)

Hydrologic characteristics of faults at Yucca Mountain, Nevada

Yucca Mountain is under study as a potential site for underground storage of high-level radioactive waste, with the principle goal being the safe isolation of the waste from the accessible environment. This paper addresses the hydrogeologic characteristics of the fault zones at Yucca Mountain, focusing primarily on the central part of the mountain where the potential repository block is located.
Date: April 29, 2001
Creator: Dickerson, Robert P.
System: The UNT Digital Library
A Preliminary Improved Test of the Flavor Independence of Strong Interactions (open access)

A Preliminary Improved Test of the Flavor Independence of Strong Interactions

The authors present an improved comparison of the strong couplings of gluons to light (u, d, and s), c, and b quarks, determined from multijet rates in flavor-tagged samples of hadronic Z{sup 0} decays recorded with the SLC Large Detector at the SLAC Linear Collider between 1993 and 1995. Flavor separation on the basis of lifetime and decay multiplicity differences among hadrons containing light, c, and b quarks was made using the SLD precision tracking system, yielding tags with high purity and low bias against {ge} 3-jet final states. They find: {alpha}{sub s}{sup uds}/{alpha}{sub s}{sup all} = 0.997 {+-} 0.011(stat) {+-} 0.011(syst) {+-} 0.005(theory), {alpha}{sub s}{sup c}/{alpha}{sub s}{sup all} = 0.984 {+-} 0.042 {+-} 0.053 {+-} 0.022, {alpha}{sub s}{sup b}/{alpha}{sub s}{sup all} = 1.022 {+-} 0.019 {+-} 0.023 {+-} 0.012.
Date: June 1, 1997
Creator: Abe, K.; Abe, K.; Akagi, T. & Collaboration, SLD
System: The UNT Digital Library
Production of {pi}{sup {+-}}, K{sup {+-}}, K{sup 0}, K*{sup 0}, {phi}, p and {Lambda}{sup 0} in Hadronic Z{sup 0} Decays (open access)

Production of {pi}{sup {+-}}, K{sup {+-}}, K{sup 0}, K*{sup 0}, {phi}, p and {Lambda}{sup 0} in Hadronic Z{sup 0} Decays

The authors have measured production rates as a function of momentum of the identified hadrons {pi}{sup +}, K{sup +}, K{sup 0}, K*{sup 0}, {phi}, p, {Lambda}{sup 0} and their antihadrons in inclusive hadronic Z{sup 0} decays, as well as separately in decays into light, c and b flavors. In addition they have compared hadron and antihadron production rates in light quark (rather than antiquark) jets. The SLD Cherenkov Ring Imaging Detector was used to identify charged hadrons. The vertex detector was used to tag high-purity samples of light- and b-flavor events. The electron beam polarization was used to tag samples of quark and antiquark jets. Clear flavor dependences are observed, consistent with expectations based upon measured production and decay properties of heavy hadrons. They use the light-flavor results to test the predictions of MLLA QCD and of various fragmentation models. Differences between hadron and antihadron production in light quark jets are observed at high momentum fraction, providing direct evidence that higher-momentum particles are more likely to contain a primary quark or antiquark, and they use these results to make a new direct measurement of strangeness suppression in the jet fragmentation process.
Date: June 1, 1997
Creator: Abe, K.; Abe, K.; Akagi, T. & Collaboration, SLD
System: The UNT Digital Library
Reservoir fracture mapping using microearthquakes: Austin chalk, Giddings field, TX and 76 field, Clinton Co., KY (open access)

Reservoir fracture mapping using microearthquakes: Austin chalk, Giddings field, TX and 76 field, Clinton Co., KY

Patterns of microearthquakes detected downhole defined fracture orientation and extent in the Austin chalk, Giddings field, TX and the 76 field, Clinton Co., KY. We collected over 480 and 770 microearthquakes during hydraulic stimulation at two sites in the Austin chalk, and over 3200 during primary production in Clinton Co. Data were of high enough quality that 20%, 31% and 53% of the events could be located, respectively. Reflected waves constrained microearthquakes to the stimulated depths at the base of the Austin chalk. In plan view, microearthquakes defined elongate fracture zones extending from the stimulation wells parallel to the regional fracture trend. However, widths of the stimulated zones differed by a factor of five between the two Austin chalk sites, indicating a large difference in the population of ancillary fractures. Post-stimulation production was much higher from the wider zone. At Clinton Co., microearthquakes defined low-angle, reverse-fault fracture zones above and below a producing zone. Associations with depleted production intervals indicated the mapped fractures had been previously drained. Drilling showed that the fractures currently contain brine. The seismic behavior was consistent with poroelastic models that predicted slight increases in compressive stress above and below the drained volume.
Date: November 1, 1996
Creator: Phillips, W. S.; Rutledge, J. T.; Gardner, T. L.; Fairbanks, T. D.; Miller, M. E. & Schuessler, B. K.
System: The UNT Digital Library
VXD3: The SLD Vertex Detector Upgrade Based on a 307 MPixel CCD System (open access)

VXD3: The SLD Vertex Detector Upgrade Based on a 307 MPixel CCD System

The SLD upgrade CCD vertex detector (VXD3) is described. Its 307 million pixels are assembled from 96 3.2 Mpixel CCDs of 13 cm{sup 2} each. The system has evolved from the pioneering CCD vertex detector VXD2, which has operated in SLD since 1992. The CCDs of VXD3 are mounted on beryllium ladders in three cylinders, providing three space point measurements along each track of about 5 microns resolution in all three co-ordinates. Significant improvements are achieved with VXD3 in impact parameter resolution (about a factor of two) and acceptance ({approximately}20%) through optimized geometry and reduced material. New readout electronics have been developed for this system.
Date: December 1995
Creator: Brau, James E.
System: The UNT Digital Library
The production of {pi}{sup {+-}}, K{sup {+-}}, p, k{sup 0} and {Lambda}{sup 0} in hadronic Z{sup 0} decays (open access)

The production of {pi}{sup {+-}}, K{sup {+-}}, p, k{sup 0} and {Lambda}{sup 0} in hadronic Z{sup 0} decays

The authors have measured production fractions and spectra for {pi}{sup {+-}}, K{sup {+-}} and p, and production spectra for K{sup 0} and {Lambda}{sup 0} in both hadronic Z{sup 0} decays and a Z{sup 0} {yields} light quark (uds) subset at SLD. The SLD Cherenkov Ring Imaging Detector was used to identify charged hadrons. The CCD vertex detector was used to select the enriched uds sample. For the global sample, the results are consistent with previous experiments. The authors observe a clear flavor dependence in production spectra, but only a small effect in hadron fractions and {xi} = ln(1/x{sub p}) peak positions.
Date: August 1, 1995
Creator: Baird, K.
System: The UNT Digital Library
Anisotropy of mechanical properties of tuff at Yucca Mountain (open access)

Anisotropy of mechanical properties of tuff at Yucca Mountain

The purpose of this study is to investigate anisotropy of mechanical properties, namely, compressive strength and modulus, for Tiva Canyon welded tuff from the starter tunnel at Yucca Mountain. Mechanical properties of Tiva Canyon Tuff are needed for the design of the ramps and drifts within the Tiva Canyon horizon. Approximately one cubic foot block samples, all of which were from the thermo -- mechanical unit TCw, were obtained from a muck pile containing excavated rock from the starter tunnel. Specimens were cored from the block samples in two distinct orientations: parallel and perpendicular to the lithophysal cavity orientation. Since lithophysal cavity orientation is predominantly horizontal in the field, parallel specimens can be considered horizontal and perpendicular specimens vertical with respect to the rock mass. The specimens were NX sized (5.4 cm diameter) and had a length-to-diameter ratio of 2:1. The air dried specimens were tested at room temperature in a triaxial chamber at confining pressures of 0.1, 5, and 10 MPa, and at a compressive axial strain rate of 10{sup {minus}5} s{sup {minus}}. The Young`s Modulus values were calculated by a least squares fit of stress - strain data between 10 and 50% of the ultimate strength.
Date: June 1, 1995
Creator: Karakouzian, M. & Hudyma, N.
System: The UNT Digital Library
Zeolite Membranes for Gas Separations (open access)

Zeolite Membranes for Gas Separations

Silicalite-1, a pure silica zeolite, was deposited on a tubular, asymmetric, {gamma}-alumina support. Single gas permeation experiments with N{sub 2}, CH{sub 4}, and CO{sub 2} were carried out on the membrane. Separation experiments for N{sub 2}/CH{sub 4} mixtures were also conducted. Single-gas permeation of H{sub 2} and separation of H{sub 2}/SF{sub 6} mixture were also carried out with the membrane. Composite membranes of silicalite and Ni-SAPO-34 were also fabricated, but no CO{sub 2}/H{sub 2} selectivity was found. It is proposed to use these membranes for methanol synthesis and separation, and for separating H{sub 2} from gasification products for use as fuel cell fuel, etc.
Date: June 1, 1995
Creator: Falconer, J. & Noble, R.
System: The UNT Digital Library
Integrated analysis of production potential and profitability of a horizontal well in the Lower Glen Rose Formation, Maverick County, Texas (open access)

Integrated analysis of production potential and profitability of a horizontal well in the Lower Glen Rose Formation, Maverick County, Texas

The U.S. Department of Energy/Morgantown Energy Technology Center (DOE/METC) awarded a contract in 1991 to Prime Energy Corporation (PEC) to demonstrate the benefit of using horizontal wells to recover gas from low permeability formations. The project area was located in the Chittim field of Maverick County, Texas. The Lower Glen Rose Formation in the Chittim field was a promising horizontal well candidate based on the heterogenous nature of the reservoir (suggested by large well-to-well variances in reserves) and the low percentage of economical vertical wells. Since there was substantial evidence of reservoir heterogeneity, it was unknown whether the selected, wellsite would penetrate a reservoir with the desired properties for a horizontal well. Thus, an integrated team was formed to combine geologic analysis, seismic interpretation, reservoir engineering, reservoir simulation, and economic assessment to analyze the production potential and profitability of completing a horizontal well in the Lower Glen Rose formation.
Date: March 1, 1995
Creator: Ammer, J. R.; Mroz, T. H.; Zammerilli, A. M.; Yost, A. B., II; Muncey, J. G. & Hegeman, P. S.
System: The UNT Digital Library
Direct Conversion of Methane to Methanol in a Non-Isothermal Catalytic Membrane Reactor (open access)

Direct Conversion of Methane to Methanol in a Non-Isothermal Catalytic Membrane Reactor

The direct partial oxidation of CH{sub 4} to CH{sub 3}OH has been studied in a non-permselective, non-isothermal catalytic membrane reactor system. A cooling tube introduced coaxially inside a tubular membrane reactor quenches the product stream rapidly so that further oxidation of CH{sub 3}OH is inhibited. Selectivity for CH{sub 3}OH formation is significantly higher with quenching than in experiments without quenching. For CH{sub 4} conversion of 4% to 7% CH{sub 3}OH selectivity is 40% to 50% with quenching and 25% to 35% without quenching.
Date: December 31, 1993
Creator: Noble, R. D. & Falconer, J. L.
System: The UNT Digital Library
Design considerations for a fiber optic communications network for power systems (open access)

Design considerations for a fiber optic communications network for power systems

The design of a fiber optic communication network for monitoring and control in power systems is discussed. It is shown that by appropriate choice of protocols, a fault-tolerant system can be built that operates in any arbitrary configuration. Since the network is based on fiber optics, it can be made fast enough for substation monitoring and control. In this application, a relatively small number of cables is required to implement a high reliability system. The network can also be used for distribution automation. In this application the network is required to reach all parts of the power system, and the fiber cable itself becomes a significant fraction of the cost of communications. However, since many applications can be supported at once, the cost per function can be reasonable.
Date: August 1, 1993
Creator: Kirkham, H.; Johnston, A. R. & Allen, G. D.
System: The UNT Digital Library
New Mexico Geochronology Research Laboratory: Zuni-Bandera volcanic field road log (open access)

New Mexico Geochronology Research Laboratory: Zuni-Bandera volcanic field road log

This field conference was designed to assemble a group of Quaternary researchers to examine the possibility of using the Zuni-Bandera volcanic field in western New Mexico as a test area for evaluating and calibrating various Quaternary dating techniques. The Zuni-Bandera volcanic-field is comprised of a large number of basaltic lava flows ranging in age from about 700 to 3 ka. Older basalts are present in the Mount Taylor volcanic field to the north. Geologic mapping has been completed for a large portion of the Zuni-Bandera volcanic field and a number of geochronological investigations have been initiated in the area. While amending this conference, please consider how you might bring your expertise and capabilities to bear on solving the many problem in Quaternary geochronology.
Date: January 1, 1993
Creator: Laughlin, A. William; Charles, Robert; Reid, Kevin & White, Carol
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: July 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
Reversible thermodynamic cycle for AMTEC power conversion (open access)

Reversible thermodynamic cycle for AMTEC power conversion

The thermodynamic cycle appropriate to an AMTEC (alkali metal thermal-to-electric converter) cell is discussed for both liquid- and vapor-fed modes of operation, under the assumption that all processes can be performed reversibly. In the liquid-fed mode, the reversible efficiency is greater than 89.6% of Carnot efficiency for heat input and rejection temperatures (900--1300 K and 400--800 K, respectively) typical of practical devices. Vapor-fed cells can approach the efficiency of liquid-fed cells. Quantitative estimates confirm that the efficiency is insensitive to either the work required to pressurize the sodium liquid or the details of the state changes associated with cooling the low pressure sodium gas to the heat rejection temperature. 10 refs.
Date: July 1, 1992
Creator: Vining, C. B.; Williams, R. M.; Underwood, M. L.; Ryan, M. A. & Suitor, J. W.
System: The UNT Digital Library