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Cross-flow, filter-sorbent catalyst for particulate, SO sub 2 and NO sub x control

Description: This report describes a new concept for integrated pollutant control: a cross-flow filter comprised of layered, gas permeable membranes that act a particulate filter, an SO{sub 2} sorbent, and a NO{sub x} reduction catalyst.
Date: August 1, 1991
Creator: Benedek, K. (Little (Arthur D.), Inc., Cambridge, MA (United States)) & Flytzani-Stephanopoulos, M. (Massachusetts Inst. of Tech., Cambridge, MA (United States))
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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High Resolution-Angle Resolved Photoemission Studies of High Temperature Superconductors

Description: Recent photoemission studies of Y 123 and Bi 2212 performed with high energy and angular resolution have provided detailed information on the nature of the states near the Fermi level. Measurements of the superconducting gap, band dispersion, and the density of states near the Fermi level in the normal state all support a Fermi liquid description of these materials. 5 refs., 4 figs.
Date: August 1, 1989
Creator: Olson, C. G.; Liu, R.; Lynch, D. W.; Veal, B. W.; Chang, Y. C.; Jiang, P. Z. et al.
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Partner: UNT Libraries Government Documents Department
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Studies of nonlinear electrodynamics of high-temperature superconductors

Description: Nonlinear electrodynamics of high-{Tc} superconductors are studied both theoretically and experimentally. For powdered samples, a novel model is presented in which the metallographically observed superconducting grains in the powder are modeled as superconducting current loops of various areas with weak links. Surprising harmonic generation behavior in an arc field, H{sub 1} cos({omega}t), is predicted by the model; the power at high harmonics show sharp dips almost periodic in a superposing dc… more
Date: August 1, 1991
Creator: Lam, Quan-Chiu H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Suppression of magnetic flux noise in YBa sub 2 Cu sub 3 O sub 7-x flux transformers

Description: We have constructed hybrid magnetometers by coupling a flux transformer of YBa{sub 2}Cu{sub 3}O{sub 7-x} to a Nb-PbIn SQUID. The low frequency (1/f) noise is dominated by fluctuations in the supercurrent circulating in the transformer, driven by vortex motion. The application of a small static magnetic field induces a supercurrent that reversibly suppresses the noise, in quantitative agreement with a model of thermally activated vortex hopping between symmetrical pairs of pinning sites. A persi… more
Date: August 1, 1991
Creator: Ferrari, M.; Wellstood, F.C.; Kingston, J.J.; Johnson, M. & Clarke, J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Flux motion and dissipation in high-temperature superconductors

Description: The effects on flux motion and dissipation of interlayer coupling of the Cu-O planes along the c-axis are considered for the high- temperature superconductors (HTS). It is argued that for the highly-anisotropic HTS, the weak interlayer coupling plays a dominant role that can be described by incoherent Josephson tunneling between superconducting Cu-O bi- or tri-layers. In YBa{sub 2}Cu{sub 3}O{sub 7}, the layers are strongly coupled, presumably because the conducting Cu-O chains short circuit the… more
Date: August 1, 1991
Creator: Gray, K.E. & Kim, D.H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Local critical current measurements on (Bi,Pb) sub 2 Sr sub 2 Ca sub 2 Cu sub 3 O sub x tape with an electromagnetic probe

Description: The ability to measure critical currents in high {Tc} superconducting tapes on a local scale is valuable for optimizing the fabrication process. This paper describes the use of induced currents from a small noncontacting electromagnetic probe to determine the critical current density in a (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x}/Ag tape on a local scale. The technique forces full field penetration into the tape locally and infers the critical current density from the Bean critical stat… more
Date: August 24, 1992
Creator: Telschow, K.L.; O'Brien, T.K. (EG and G Idaho, Inc., Idaho Falls, ID (United States)); Lanagan, M.T. & Kaufman, D.Y. (Argonne National Lab., IL (United States))
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Partner: UNT Libraries Government Documents Department
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Specific heat evidence for strong coupling in YBa sub 2 Cu sub 3 O sub 7

Description: Specific heat data for YBa{sub 2}Cu{sub 3}O{sub 7} are consistent with {gamma} = 15 {plus minus} 3 mJ/mole{center dot}K{sup 2} and 2{Delta}{sub 0}/k{Tc} = 6.8 {plus minus} 0.6. These results indicate that strong-coupling effects are present but that the coupling is unlikely to be predominantly a conventional electron-phonon interaction. 8 refs., 1 fig.
Date: August 1, 1990
Creator: Gordon, J. E.; Fisher, R. A.; Kamin, S. & Phillips, N. E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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New materials for thick-film electronics

Description: Certain ceramic compounds such as rare-earth perovskites and transition-metal diborides that exhibit metallic conductivity are readily available or can be easily synthesized. Some are stable in air firing temperatures typical of hybrid-circuit processing. The work described is part of an exploratory program to determine whether these materials can be used as low-cost alternatives to precious metals for thick-film conductor and low-resistor inks or as substitutes for copper in nitrogen-fireable … more
Date: August 1, 1990
Creator: Hoffheins, B.S. & Lauf, R.J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Flux Motion and Dissipation in High-Temperature Superconductors

Description: The effects on flux motion and dissipation of interlayer coupling of the Cu-O planes along the c-axis are considered for the high- temperature superconductors (HTS). It is argued that for the highly-anisotropic HTS, the weak interlayer coupling plays a dominant role that can be described by incoherent Josephson tunneling between superconducting Cu-O bi- or tri-layers. In YBa{sub 2}Cu{sub 3}O{sub 7}, the layers are strongly coupled, presumably because the conducting Cu-O chains short circuit the… more
Date: August 1, 1991
Creator: Gray, K. E. & Kim, D. H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Critical current density, irreversibility line, and flux creep activation energy in silver-sheathed Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} superconducting tapes

Description: Transport data, magnetic hysteresis and flux creep activation energy experimental results are presented for silver-sheathed high-{Tc} Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} superconducting tapes. The 110 K superconducting phase was formed by lead doping in a Bi-Sr-Ca-Cu-0 system. The transport critical current density was measured at 4.0 K to be 0.7 {times} 10{sup 5} A/cm{sup 2} (the corresponding critical current is 74 A) at zero field and 1.6 {times} 10{sup 4} A/cm{sup 2} at 12 T for H{… more
Date: August 1, 1992
Creator: Shi, D.; Wang, Z.; Sengupta, S.; Smith, M.; Goodrich, L. F.; Dou, S. X. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Influence of doping on the electronic structure of (La, Sr){sub 2}CuO{sub 4}

Description: High statistics, (> 4 x 10{sup 8} counts), room temperature measurements of the electron-positron momentum density of La{sub 2-x}Sr{sub x}CuO{sub 4} have been performed for samples with Sr concentrations of x - 0.0, 0.1, 0.13 and 0.2. These spectra have been analyzed in conjunction with theoretical calculations of the electron-positron momentum density. The metallic samples show features consistent with the presence of a Fermi surface, but its evolution with increasing Sr concentration does not… more
Date: August 23, 1993
Creator: Howell, R. H.; Fluss, M. J.; Sterne, P. A.; Kaiser, J. H.; Kitazawa, K. & Kojima, H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Effective activation energy in the Bi-Sr-Ca-Cu-O systems

Description: Magnetic relaxation in the Bi-Sr-Ca-Cu-O systems has been investigated in a wide temperature regime. Previously reported studies of the effective activation energy, U, have been controversial in terms of temperature and field dependence of the critical current density, j{sub c}. We have considered the temperature dependence of j{sub c} and constructed the U-j (or M) curves for the Bi-Sr-Ca-Cu-O system. We found that at a constant driving force and temperature, U is considerably higher for 2245 … more
Date: August 1, 1992
Creator: Sengupta, S.; Shi, D.; Wang, Z.; Smith, M. & McGinn, P. J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Engineering development of advanced coal-fired low emission boiler systems. First quarterly report, FY94, January 1994--March 1994

Description: The major task during this quarter was testing and evaluation of the 25 MBtu/hr Toroidal Vortex Combustor (TVC) at Textron Defense Systems`` (TDS) Haverhill laboratories. The tests were completed and the results are being evaluated along with other scale up and integration issues. The preliminary conclusion is that the NOx performance and current design uncertainties do not justify the development risk within the Low Emission Boiler System (LEBS) timetable. Further program effort will focus on … more
Date: August 1, 1994
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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{open_quotes}Fishtails{close_quotes} in 123-superconductors

Description: Several high quality (RE)Ba{sub 2}Cu{sub 3}O{sub 7-x} single crystals with RE = Y, Yb and Dy, with varying amounts of Au- and Al-impurities have been investigated by SQUID magnetometry. All samples show fishtail behavior. Differences in the sample preparation only influence the position of the maximum in J{sub c}. The authors conclude that the fishtail phenomenon is not a material specific property, but a generally occurring property of the flux line lattice.
Date: August 1, 1994
Creator: Werner, M.; Sauerzopf, F. M.; Weber, H. W.; Veal, B. W.; Licci, F.; Winzer, K. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Cross-flow, filter-sorbent catalyst for particulate, SO{sub 2} and NO{sub x} control. Sixth quarterly technical progress report

Description: This report describes a new concept for integrated pollutant control: a cross-flow filter comprised of layered, gas permeable membranes that act a particulate filter, an SO{sub 2} sorbent, and a NO{sub x} reduction catalyst.
Date: August 1, 1991
Creator: Benedek, K. & Flytzani-Stephanopoulos, M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Development of novel copper-based sorbents for hot-gas cleanup. [Quarterly] technical report, December 1, 1991--February 29, 1992

Description: The objective of this investigation is to evaluate several novel copper-based binary oxides for their suitability as regenerable sorbents for hot gas cleanup application in the temperature range of 650{degrees} to 850{degrees}C. To achieve this objective, several novel copper-based binary oxide sorbents will be prepared. Experimental tests will be conducted at ambient pressure to determine the stability, sulfidation capacity, regenerability, and sulfidation kinetics of the novel sorbents. Tests… more
Date: August 1, 1992
Creator: Abbasian, J.; Hill, A. H.; Wangerow, J. R.; Flytzani-Stephanopoulos, M.; Bo, L. & Patel, C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Technology development for iron Fischer-Tropsch catalysts. Technical progress report number 13, 26 September 1993--26 December 1993

Description: The objectives of this contract are to develop a technology for the production of active and stable iron (Fe) Fischer-Tropsch catalysts for use in slurry-phase synthesis reactors and to develop a scale up procedure for large-scale synthesis of such catalysts for process development and long-term testing in slurry bubble-column reactors. With a feed containing hydrogen (H{sub 2}) and carbon monoxide (CO) in the molar ratio of 0.5 to 1.0 to the slurry bubble-column reactor, the catalyst performan… more
Date: August 1, 1994
Creator: Frame, R. R. & Gala, H. B.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Recent advances in high-temperature superconductor wire fabrication and applications development

Description: In this paper, recent advances in fabrication of HTS wires are summarized, and detailed discussion is provided for developments in near- and intermediate-term applications. Near-term applications, using presently obtainable current densities, include: liquid-nitrogen depth sensors, cryostat current leads, and magnetic bearings. Intermediate-term applications, using current densities expected to be available in the near future include fault-current limiters and short transmission lines. 25 refs.
Date: August 1, 1992
Creator: Hull, J. R. & Uherka, K. L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Reformers for the production of hydrogen from methanol and alternative fuels for fuel cell powered vehicles

Description: The objective of this study was (i) to assess the present state of technology of reformers that convert methanol (or other alternative fuels) to a hydrogen-rich gas mixture for use in a fuel cell, and (ii) to identify the R&D needs for developing reformers for transportation applications. Steam reforming and partial oxidation are the two basic types of fuel reforming processes. The former is endothermic while the latter is exothermic. Reformers are therefore typically designed as heat exchange … more
Date: August 1, 1992
Creator: Kumar, R.; Ahmed, S.; Krumpelt, M. & Myles, K. M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Interband transitions in YBa{sub 2}Cu{sub 3}O{sub 7}

Description: Using rotating analyzer ellipsometry, we have measured all three components of the dielectric tensor of YBa{sub 2}CU{sub 3}O{sub 7} from near-infrared to vacuum-ultraviolet (0.7 -- 24 eV). In the low energy region the spectra for a -- b polarization can be well modelled by a Drude free-carrier response with a frequency independent scattering rate. Below 10 eV we observe strongly anisotropic interband transitions involving the partially filled valence band and the conduction band. At higher ener… more
Date: August 1, 1991
Creator: Kircher, J.; Humlicek, J.; Garriga, M.; Cardona, M.; Fuchs, D.; Habermeier, H. U. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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High oxygen pressure synthesis of new copper oxide superconductors

Description: The unique coordination of the copper ions in +1, +2, and +3 oxidation states which are stable in a range of oxygen partial pressure, 10{sup {minus}6} < P(O{sub 2}) < 10{sup 3} atm, makes possible the formation of a wide variety of distinct structures. By controlling the oxygen pressure during the synthesis and annealing, the distribution of metal- and oxygenions can be modified on an atomic scale to optimize the structural and electronic properties. We present several examples of compounds for… more
Date: August 1, 1993
Creator: Dabrowski, B.; Zhang-MacCoy, V.; Wang, Z.; Hannon, R.; Jorgensen, J. D.; Hunter, B. A. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Magnetic hysteresis and flux creep of YBa{sub 2}Cu{sub 3}O{sub x} grown by the melt-powder-melt-growth (MPMG) process

Description: Magnetic hysteresis and flux creep of melt-powder-melt-growth (MPMG) YBa{sub 2}Cu{sub 3}O{sub x} containing nominal 0, 25 and 40 mole% Y{sub 2}BaCuO{sub 5} (21 1) were measured in the temperature range of 5 to 80 K and in magnetic fields up to 5 T. With the introduced fine dispersion of second phase 211 particles, the critical magnetization current density J{sub c} shows a weak field dependence over a wide range of temperature, and the effective pinning energy U{sub eff} is much enhanced. From … more
Date: August 24, 1992
Creator: Kung, P. J.; McHenry, M. E.; Maley, M. P.; Willis, J. O.; Murakami, M. & Tanaka, S.
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Partner: UNT Libraries Government Documents Department
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Local structure in oxygen-doped La{sub 2}CuO{sub 4+{delta}}

Description: Oxygen doped La{sub 2}CuO{sub 4+{delta}}, due to the unusually large mobility of the oxygen ions at high temperatures, is the only cuprate which has macroscopic phase separation of doped holes. We discuss our studies of La{sub 2}CuO{sub 4+{delta}}, including phase separation, distributed local structure whose onset coincides with-phase separation and the observation that in the presence of doped holes two distinct copper sites copper sites are generated, an observation which contrasts with resu… more
Date: August 4, 1993
Creator: Hammel, P. C.; Reyes, A. P.; Ahrens, E. T.; MacLaughlin, D. E.; Thompson, J. D.; Fisk, Z. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Design of high-T[sub c] superconducting bolometers for a far infrared imaging array

Description: The design of high-[Tc] superconducting bolometers for use in a far infrared imaging array from wavelengths 30--100[mu]m is discussed. Measurements of the voltage noise in thin films of YBa[sub 2]CU[sub 3]O[sub 7-[var sigma]] on yttria-stabilized zirconia buffer layers on silicon substrates are used to make performance estimates. Useful opportunities exist for imaging and spectroscopy with bolometer arrays made on micro-machined silicon membranes. A circuit on each pixel which performs some sig… more
Date: August 1, 1992
Creator: Verghese, S.; Richards, P. L.; Fork, D. K.; Char, K. & Geballe, T. H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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