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Conversion of Oxyfluoride Based Coated Conductors

Description: Direct measurements of HF pressure in equilibrium with the film during the BaF2 process are sorely needed. It is the HF partial pressure that governs the rate at which the film composition is changing and is, therefore, an important factor in controlling the composition/time trajectory of the film. Establishing the composition/time trajectory of both MOD-derived and e-beam derived films for a given set of conditions is another goal for the project. These studies will provide a fundamental understanding of the ex situ process for producing coated conductors.
Date: November 1, 2006
Creator: Wesolowski, Dan
Partner: UNT Libraries Government Documents Department

Electron Backscatter Diffraction in Low Vacuum Conditions

Description: Most current scanning electron microscopes (SEMs) have the ability to analyze samples in a low vacuum mode, whereby a partial pressure of water vapor is introduced into the SEM chamber, allowing the characterization of nonconductive samples without any special preparation. Although the presence of water vapor in the chamber degrades electron backscatter diffraction (EBSD) patterns, the potential of this setup for EBSD characterization of nonconductive samples is immense. In this chapter we discuss the requirements, advantages and limitations of low vacuum EBSD (LV-EBSD), and present how this technique can be applied to a two-phase ceramic composite as well as hydrated biominerals as specific examples of when LV-EBSD can be invaluable.
Date: July 17, 2008
Creator: El-Dasher, B S & Torres, S G
Partner: UNT Libraries Government Documents Department

Oxidation of Mo-41 Re at Low Oxygen Pressures: 2000 Status Report

Description: Rhenium generally improves the properties of molybdenum, and, therefore, there is interest in use of Mo-Re alloys in space system applications. Both Mo and Re have relatively low solubilities for oxygen but readily form oxide scales when exposed to oxidizing environments above {approx}350 C. Studies are being conducted on Mo-41Re to determine the rate of oxidation, type of scale formation, and effects on mechanical properties as a function of temperature and partial pressure of oxygen. Thus far, weight gains associated with formation of MoO{sub 2} have been found for P{sub o{sub 2}} < 10{sup -3} Pa (torr) in vacuum, and weight losses associated with evaporation of MoO{sub 3} above 10{sup -3} Pa. However, no significant changes in tensile properties were measured.
Date: December 6, 2000
Creator: DiStefano, JR
Partner: UNT Libraries Government Documents Department

Defect structure of the mixed-conducting Sr-Fe-Co-O system

Description: Electrical conductivity of the mixed-conducting Sr-Fe-Co-O system was investigated at high temperatures and various oxygen partial pressures (pO2). The system exhibits not only high combined electrical and oxygen ionic conductivities but also structural stability in both oxidizing and reducing environments. Conductivity of SrFeCo{sub 0.5}O{sub x} increases with temperature and pO2, within the experiment pO2 range (1-10{sup -18} atm). p-type conduction was observed, the activity energy of which decreases with pO2. A model of the defect chemistry in the Sr-Fe-Co-O system is proposed. The pO2- dependent conducting behavior can be understood by considering the trivalent-to-divalent transition of the transition metal ions in the system.
Date: November 1, 1996
Creator: Ma, B.; Balachandran, U.; Chao, C.-C. & Park, J.-H.
Partner: UNT Libraries Government Documents Department

Index of refraction versus oxygen partial pressure for tantalum oxide and silicon dioxide films produced by ion beam deposition

Description: Tantalum oxide and silicon oxide films were made using an ion beam sputtering system. It was found that even though these films were deposited from oxide targets, additions of oxygen were necessary to achieve stoichiometry and hence index of refraction. It was observed that the tantalum oxide target changed color from white to gray, indicating that the oxygen was being depleted from the target. The addition of oxygen to the chamber during deposition replenished the target and improved film stoichiometry. The deposition rate decreased with increasing oxygen partial pressure. It was experimentally determined that by varying the oxygen partial pressure and keeping all other variables fixed, the index of refraction of the film changed in a predictable manner. That is, as the oxygen partial pressure was increased, the index decreased rapidly initially and then reached a saturation point where it stayed fixed with oxygen content. With this data a coating process can be set up using the minimum amount of oxygen (thus increasing filament lifetime) to produce a fully stoichiometric film that has a fixed index. This paper will present the details of these observations and results.
Date: April 30, 1998
Creator: Goward, W.D.; Petersen, H.E.; Dijaili, S.P. & Walker, J.D.
Partner: UNT Libraries Government Documents Department

Carbon Dioxide, Hydrographic, and Chemical Data Obtained During the R/V Meteor Cruise 22/5 in the South Atlantic Ocean (WOCE Section A10, December 1992-January 1993)

Description: This data documentation discusses the procedures and methods used to measure total carbon dioxide (TCO{sub 2}) and total alkalinity (TALK) at hydrographic stations, as well as the underway partial pressure of CO{sub 2} (pCO{sub 2}) during the R/V Meteor Cruise 22/5 in the South Atlantic Ocean (Section A10). Conducted as part of the World Ocean Circulation Experiment (WOCE), the cruise began in Rio de Janeiro on December 27, 1992, and ended after 36 days at sea in Capetown, South Africa, on January 31, 1993. Measurements made along WOCE Section A10 included pressure, temperature, and salinity [measured by conductivity, temperature, and depth (CTD) sensor], bottle salinity, bottle oxygen, phosphate, nitrate, nitrite, silicate, chlorofluorocarbons (CFC-1 1 , CFC-12), TCO{sub 2}, TALK, and underway pCO{sub 2}. The TCO{sub 2} was measured by using two Single-Operator Multiparameter Metabolic Analyzers (SOMMAs) for extracting CO{sub 2} from seawater samples that were coupled to a coulometer for detection of the extracted CO{sub 2}. The overall precision and accuracy of the analyses was {+-} 1.9 {micro}mol/kg. Samples collected for TALK were measured by potentiometric titration; precision was {+-}2.0 {micro}mol/kg. Underway pCO{sub 2} was measured by infrared photometry with a precision of {+-} 2.0 {micro}atm. The work aboard the R/V Meteor was supported by the U.S. Department of Energy under contract DE-AC02-76CHOO016, and the Bundesministerium fir Forschung und Technologies through grants 03F0545A and MPG 099/1.
Date: December 1, 1998
Creator: Kozyr, A.
Partner: UNT Libraries Government Documents Department

Development of dense ceramic membranes for hydrogen separation.

Description: We developed novel cermet (i.e., ceramic-metal composite) membranes for separating hydrogen from gas mixtures at high temperature and pressure. The hydrogen permeation rate in the temperature range of 600-900 C was determined for three classes of cermet membranes (ANL-1, ANL-2, and ANL-3). Among these membranes, ANL-3 showed the highest hydrogen permeation rate, with a maximum flux of 3.2 cm{sup 3}/min-cm{sup 2} for a 0.23-mm-thick membrane at 900 C. Effects of membrane thickness and hydrogen partial pressure on permeation rate indicated that bulk diffusion of hydrogen is rate-limiting for ANL-3 membranes. The lack of degradation in permeation rate during exposure to a simulated syngas mixture suggests that ANL-3 membranes are chemically stable and suitable for long-term operation.
Date: November 1, 2000
Creator: Balachandran, U.; Lee, T. H.; Zhang, G.; Dorris, S. E.; Rothenberger, K. S.; Martello, D. V. et al.
Partner: UNT Libraries Government Documents Department

DOE final report: Studies on the microbial formation of methane

Description: The microbial formation of methane is carried out by methanogens which are found wherever active anaerobic degradation of organic matter occurs. We developed a procedure for reliable culture of 'Methanococus jannaschii' which yields 8 g wet weight of cells per liter of medium. To initiate a study of proteomics, this organism was grown at two levels of hydrogen partial pressure, very low (650 Pa) and high (178 kPa). When cells were exposed to hydrogen excess conditions, they possessed very low or undetectable levels of four flagella-related polypeptides, whereas, when hydrogen became limiting, these proteins were synthesized. Thus, use of proteomics showed, for the first time, that this methanogen can regulate expression of proteins, and these experiments open the door for general studies of regulation in this hyperthermophile.
Date: April 1, 2001
Creator: Wolfe, Ralph S.
Partner: UNT Libraries Government Documents Department

Dense ceramic membranes for hydrogen separation.

Description: We have developed cermet membranes that nongalvanically separate hydrogen from gas mixtures. The highest measured hydrogen flux was 20.0 cm{sup 3} (STP)/min-cm{sup 2} for an ANL-3a membrane at 900 C. For ANL-3 membranes with thickness of 40-500 {micro}m, hydrogen permeation is limited by the bulk diffusion of hydrogen through the metal phase. The effect of hydrogen partial pressure on permeation rate confirmed this conclusion, suggesting that higher permeation rates may be obtained by decreasing the membrane thickness. Permeation rate in a syngas atmosphere for times up to 190 h showed no degradation in performance, which indicates that ANL-3 membranes may be suitable for long-term, practical hydrogen separation.
Date: May 7, 2002
Creator: Balachandran, U.; Lee, T. H.; Wang, S.; Zhang, G. & Dorris, S. E.
Partner: UNT Libraries Government Documents Department

Coupled Thermal and Water Management in Polymer-Electrolyte FuelCells

Description: Thermal and water management are intricately coupled in polymer-electrolyte fuel cells. In this paper, we simulate fuel-cell performance and account for nonisothermal phenomena. The transport of water due to a temperature gradient and its associated effects on performance are described, with the increase of reactant dilution by the water-vapor partial pressure being the most dominant. In addition, simulations are undergone to find the optimum operating temperature and maximum power density as a function of external heat-transfer coefficient. The shape of the optimization curves and the magnitudes of the nonisothermal phenomena are also detailed and explained.
Date: November 1, 2006
Creator: Weber, Adam Z. & Newman, John
Partner: UNT Libraries Government Documents Department

Intermittent Elevated Radium Concentrations in Coastal Plain Groundwater of South Carolina, U.S.A.

Description: To learn the cause of intermittent radium concentrations in groundwater of Coastal Plain aquifers, 31 groundwater wells in South Carolina, U.S.A. were sampled for radium and other geochemical parameters. Sediments cored from near the well screens were also sampled to examine any relationship between sediment properties and radium concentration in the groundwater. Elevated radium concentrations only occurred in groundwater with low electrical conductivity and pH values below 6.3. The adsorption edge for radium on hematite--a major surface active mineral in these aquifers--is at a pH value of about 6. Near this value, small changes in pH can result in significant adsorption or desorption of radium. In groundwater with initially low alkalinity, small intermittent decreases in partial pressure of carbon dioxide in groundwater cause decreases in pH and desorption of radium. The result is intermittent elevated radium concentrations.
Date: September 22, 2005
Creator: Denham, Miles; Millings, Margaret & Noonkester, Jay
Partner: UNT Libraries Government Documents Department

THE EFFECT OF 3HE ON LOW PRESSURE HYDRIDE ABSORPTION MEASUREMENTS WITH TRITIUM

Description: Absorption isotherm data exists for a wide variety of hydrogen-metal systems. When working with high purity gases, appropriately sized equipment, and hydrides with equilibrium pressures above several hundred Pa, data collection is relatively straightforward. Special consideration must be given to experiments involving low equilibrium pressure hydrides, as even sub-ppm levels of gas impurities can generate partial pressures many times greater than the equilibrium pressures to be measured. Tritium absorption experiments are further complicated by the continuous generation of helium-3. The time required to transfer and absorb a known quantity of tritium onto a sample ultimately limits the minimum pressure range that can be studied using the standard technique. Equations are presented which show the pressure of helium-3 in a sample cell based on the amount of tritium to be absorbed, the sample cell volume and temperature, and the decay time of tritium. Sample calculations for zirconium show that at 300 C, the estimated helium-3 pressure in the cell will be equal to the hydrogen absorption pressure after only milliseconds of tritium decay. An alternate method is presented that permits the collection of equilibrium data at pressures orders of magnitude lower than possible using a direct approach.
Date: January 20, 2011
Creator: Staack, G. & Klein, J.
Partner: UNT Libraries Government Documents Department

Spatial distribution of the CO transient response of a PEFC

Description: We report on the investigation of the current distribution of a PEFC under the influence of CO impurities in the hydrogen feed stream by application of the segmented cell system. Stepping the CO partial pressure of the anode feed stream from 0 to 100 ppm CO the current response of the cell was recorded for different stoichiometric flows. A poisoning time delay occurs along the flow path due to the anode flow rate. Also anode and cathode processes, e.g. CO turnover and oxygen mass transport limitation contribute to the time response of the cell.
Date: January 1, 2002
Creator: Bender, G. (Guido) & Zawodzinski, T. A. (Thomas A.), Jr.
Partner: UNT Libraries Government Documents Department

Oxidation of interconnect alloys in an electric field

Description: The effect of an electric field on the oxidation of interconnect alloys was examined with a representative array of materials: an iron-base ferritic chromia former (E-brite), an iron-base ferritic chromia former with Mn and La (Crofer 22APU), a nickel-base chromia former (IN-718), and a nickelbase chromia former with Mn and La (Haynes 230). Environmental variables include temperature and oxygen partial pressure. The resulting scales were examined to determine if applied electrical current induces changes in mechanism or scale growth kinetics.
Date: October 1, 2006
Creator: Holcomb, G.R.; Alman, D.E.; Adler, T.A. & Jablonski, P.D.
Partner: UNT Libraries Government Documents Department

Carbon Dioxide, Hydrographic, and Chemical Data Obtained During the R/V Knorr Cruises in the North Atlantic Ocean on WOCE Sections AR24 (November 2-December 5, 1996) and A24, A20, and A22 (May 30-September 3, 1997)

Description: This documentation describes the procedures and methods used to measure total carbon dioxide (TCO{sub 2}) total alkalinity (TALK), and partial pressure of CO{sub 2} (pCO{sub 2}) at hydrographic stations on the North Atlantic Ocean sections AR24, A24, A20, and A22 during the R/V Knorr Cruises 147-2, 151-2, 151-3, and 151-4 in 1996 and 1997. Conducted as part of the World Ocean Circulation Experiment (WOCE), the expeditions began at Woods Hole, Massachusetts, on October 24, 1996, and ended at Woods Hole on September 3, 1997. Instructions for accessing the data are provided. A total of 5,614 water samples were analyzed for discrete TCO{sub 2} using two single-operator multiparameter metabolic analyzers (SOMMAs) coupled to a coulometer for extracting and detecting CO{sub 2}. The overall accuracy of the TCO{sub 2} determination was {+-} 1.59 {micro}mol/kg. The TALK was determined in a total of 6,088 discrete samples on all sections by potentiometric titration using an automated titration system developed at the University of Miami. The accuracy of the TALK determination was {+-} 3 {micro}mol/kg. A total of 2,465 discrete water samples were collected for determination of pCO{sub 2} in seawater on sections A24, A20, and A22. The pCO{sub 2} was measured by means of an equilibrator-IR system by scientists from Lamont-Doherty Earth Observatory. The precision of the measurements was estimated to be about {+-} 0.15%, based on the reproducibility of the replicate equilibrations on a single hydrographic station. The North Atlantic data set is available as a numeric data package (NDP) from the Carbon Dioxide Information Analysis Center. The NDP consists of 12 ASCII data files, one Ocean Data View-formatted data file, a NDP-082 ASCII text file, a NDP-082 PDF file, and this printed documentation, which describes the contents and format of all files, as well as the procedures and methods used to obtain ...
Date: October 23, 2003
Creator: Johnson, K.M.
Partner: UNT Libraries Government Documents Department

Phase diagram studies in the SrO-CuO-Ti02 system: applications to YBCO coated conductors.

Description: SrTiO3 (STO) is a potential buffer layer material for use in YBa2Cu3Oy (YBCO) coated conductors based on the IBAD MgO process. However, the interactions with YBCO are not yet fully understood and little information exists in the way of phase diagrams. With this in mind, the tie-line between STO and SrCuO2 in the pseudo-ternary system SrO-CuO-TiO2 was investigated. Phase assemblages and compositions were determined by x-ray diffraction and electron microscopy in the temperature range of 1000oC to 1100oC in oxygen partial pressures of 1%, 10%, and 100%. Preliminary results showed that an appreciable amount of copper substitutes into the STO crystal structure. Conversely, Ti substitution into the SrCuO2 phase was not detected.
Date: January 1, 2001
Creator: Ayala, A. (Alicia); Holesinger, T. G. (Terry G.); Peterson, E. J. (Eric J.) & Archuleta, M. C. (Milena C.)
Partner: UNT Libraries Government Documents Department

Thermodynamic Modeling of Hanford Waste Tank 241-AN-107

Description: The high level waste storage double-shell tanks at the Hanford site are highly basic. The high basicity is a key factor in controlling the chemical behavior of different components of the waste and in influencing the corrosion rate of the carbon steel primary tanks. However, the introduction of atmospheric CO2 can act to reduce the pH of the tank wastes over time and possibly alter the corrosion rate of the carbon steel tanks. In order to at least partially address this issue for waste tank 241-AN-107, thermodynamic modeling calculations were performed to predict the changes in pH and carbonate concentration that could occur as CO2 is absorbed from the atmosphere. The calculations extended to complete equilibrium with the partial pressure of CO2 in the atmosphere (i.e. pCO2 = 10-3.5 atm). Simulations were performed for both the “upper” segments of tank 241-AN-107, which have been influenced by the introduction of high concentrations of NaOH to the supernatant, and for the “lower” segments where the salt cake/interstitial liquid have not been substantially altered by the introduction of base concentration.
Date: September 7, 2005
Creator: Felmy, Andrew R.
Partner: UNT Libraries Government Documents Department

ATOMIC SCALE CHARACTERIZATION OF OXYGEN VACANCY DYNAMICS BY IN SITU REDUCTION AND ANALYTICAL ATOMIC RESOLUTION STEM.

Description: In this study, we present nano-scale investigations of point defect dynamics in perovskite oxides by correlated atomic resolution high angle annular dark field imaging (HAADF) and electron energy loss spectroscopy (EELS). The point defect dynamics and interactions during in-situ reduction in the microscope column are analyzed. In particular, oxygen vacancy creation, diffusion and clustering are studied, as oxygen vacancies comprise the majority of the point defects present in these perovskite oxide systems [1]. The results have been acquired using the JEOL2010F, a STEM/TEM, equipped with a 200 keV field emission gun, a high angle annular dark field detector and a post column Gatan imaging filter (GIF). The combination of the Z-contrast and EELS techniques [2] allows us to obtain direct images (spatial resolution of 2 {angstrom}) of the atomic structure and to correlate this information with the atomically resolved EELS information (3s acquisition time, 1.2 eV energy resolution). In-situ heating of the material is performed in a Gatan double tilt holder with a temperature range of 300 K-773 K at an oxygen partial pressure of P{sub O{sub 2}} = 5 * 10{sup -8} Pa.
Date: August 4, 2002
Creator: KLIE,R.F.; BROWNING,N.D. & ZHU,Y.
Partner: UNT Libraries Government Documents Department

Corrosion performance of structural alloys.

Description: Component reliability and long-term trouble-free performance of structural materials are essential in power-generating and gasification processes that utilize coal as a feedstock. During combustion and conversion of coal, the environments encompass a wide range of oxygen partial pressures, from excess-air conditions in conventional boilers to air-deficient conditions in 10W-NO{sub x} and gasification systems. Apart from the environmental aspects of the effluent from coal combustion and conversion, one concern from the systems standpoint is the aggressiveness of the gaseous/deposit environment toward structural components such as waterwall tubes, steam superheaters, syngas coolers, and hot-gas filters. The corrosion tests in the program described in this paper address the individual and combined effects of oxygen, sulfur, and chlorine on the corrosion response of several ASME-coded and noncoded structural alloys that were exposed to air-deficient and excess-air environments typical of coal-combustion and gasification processes. Data in this paper address the effects of preoxidation on the subsequent corrosion performance of structural materials such as 9Cr-1Mo ferritic steel, Type 347 austenitic stainless steel, Alloys 800, 825, 625, 214, Hastelloy X, and iron aluminide when exposed at 650 C to various mixed-gas environments with and without HCI. Results are presented for scaling kinetics, microstructural characteristics of corrosion products, detailed evaluations of near-surface regions of the exposed specimens, gains in our mechanistic understanding of the roles of S and Cl in the corrosion process, and the effect of preoxidation on subsequent corrosion.
Date: July 15, 1999
Creator: Natesan, K.
Partner: UNT Libraries Government Documents Department

Thermodynamics and stability of the mixed-conducting Sr-Fe-Co-O system.

Description: Mixed-conducting Sr-Fe-Co oxides have potential applications in dense ceramic membranes for high-purity oxygen separation and/or methane conversion to produce syngas (CO + H{sub 2}), because of their combined high electronic/ionic conductivity and significant oxygen permeability. We studied the crystal structure and microstructure of the system in X-ray diffraction experiments and by using scanning electron microscopy, respectively. Thermogravimetric analysis was conducted on the SrFeCo{sub 0.5}O{sub x} sample in environments of various oxygen partial pressures (pO{sub 2}). Conductivity increased while weight decreased with increasing temperature. Activation energy decreased while conductivity increased with increasing pO{sub 2}. The pO{sub 2}-dependent conducting behavior of the SrFeCo{sub 0.5}O{sub x} system can be understood by considering the trivalent-to-divalent transition of transition-metal ions.
Date: April 28, 1999
Creator: Ma, B.
Partner: UNT Libraries Government Documents Department

Carbon dioxide, hydrographic, and chemical data obtained during the R/V Meteor cruise 15/3 in the South Atlantic Ocean. WOCE Section A9, February--March 1991

Description: The increase in atmospheric carbon dioxide (CO{sub 2}) concentrations (as well as in other radiatively active trace gases) because of human activity has produced serious concern regarding the heat balance of the global atmosphere (Moore and Braswell 1994). The increasing concentrations of these gases may intensify the earth`s natural greenhouse effect, and force the global climate system in ways that are not well understood. The oceans play a major role in global carbon cycle processes. Carbon in the oceans is unevenly distributed because of complex circulation patterns and biogeochemical cycles, neither of which are completely understood. To better understand the ocean`s role in climate and climatic changes, several large experiments have been conducted in the past, and others are currently under way. The World Ocean Circulation Experiment (WOCE) is a major component of the World Climate Research Program. Although total carbon dioxide (TC0{sub 2}) is not an official WOCE measurement, a coordinated effort, supported in the United States by the US Department of Energy (DOE), is being made on WOCE cruises (through 1998) to measure the global, spatial, and temporal distributions of TC0{sub 2} and other carbon-related parameters. The CO{sub 2} survey goals include estimation of the meridional transport of inorganic carbon in a manner analogous to the oceanic heat transport (Bryden and Hall 1980; Brewer et al. 1989; Roemmich and Wunsch 1985), evaluation of the exchange of CO{sub 2} between the atmosphere and the ocean, and preparation of a database suitable for carbon-cycle modeling and the subsequent assessment of the anthropogenic C0{sub 2} increase in the oceans. The C0{sub 2} survey is taking advantage of the sampling opportunities provided by the WOCE cruises during this period. The final data set is expected to cover {approx_gt}23,000 stations.
Date: June 1995
Creator: Johnson, K. M.; Wallace, D. W.R .; Wilke, R. J.; Goyet, C. & Kozyr, A.
Partner: UNT Libraries Government Documents Department

Carbon Dioxide, Hydrographic, and Chemical Data Obtained During the R/V Thomas G. Thompson Cruise in the Pacific Ocean

Description: This data documentation discusses the procedures and methods used to measure total carbon dioxide (TCO2), total alkalinity (TALK), and radiocarbon (delta 14C), at hydrographic stations, as well as the underway partial pressure of CO2 (pCO2) during the R/V Thomas G. Thompson oceanographic cruise in the Pacific Ocean (Section P10). Conducted as part of the World Ocean Circulation Experiment (WOCE), the cruise began in Suva, Fiji, on October 5, 1993, and ended in Yokohama, Japan, on November 10, 1993. Measurements made along WOCE Section P10 included pressure, temperature, salinity [measured by conductivity temperature, and depth sensor (CTD)], bottle salinity, bottle oxygen, phosphate, nitrate, silicate, chlorofluorocarbons (CFC-11, CFC-12), TCO2, TALK, delta 14C, and underway pCO2.
Date: August 1, 1999
Creator: Sabine, C.L.; Key, R.M.; Hall, M. & Kozyr, A.
Partner: UNT Libraries Government Documents Department

Current status of dense ceramic membranes for hydrogen separation.

Description: We have developed cermet membranes that nongalvanically separate hydrogen from gas mixtures. The highest measured hydrogen flux was 16.2 cm{sup 3} (STP)/min-cm{sup 2} for an ANL-3a membrane at 900 C. For ANL-3 membranes with thickness of 0.04-0.5 mm, permeation rate is limited by the bulk diffusion of hydrogen through the metal phase. The effect of hydrogen partial pressure on permeation rate confirmed this conclusion and suggested that higher permeation rates may be obtained by decreasing the membrane thickness. Permeation rate in a syngas atmosphere for times up to 190 h showed no degradation in performance, which indicates that ANL-3 may be suitable for long-term, practical hydrogen separation.
Date: February 22, 2002
Creator: Balachandran, U.; Lee, T. H.; Wang, S.; Zhang, G. & Dorris, S. E.
Partner: UNT Libraries Government Documents Department