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Magnetization studies of oxides related to the high temperature cuprate superconductors

Description: The magnetic properties related to the following high temperature superconductors were measured utilizing a Faraday magnetometer: BaCuO{sub 2+x}, La{sub 2} CuO{sub 4}, Sr{sub 2} RhO{sub 4}, Sr{sub 2} VO{sub 4}, and Sr{sub 2} CuO{sub 3}. Neutron diffraction, magnetic susceptibility, and heat capacity measurements are discussed.
Date: June 19, 1995
Creator: Wang, Z.
Partner: UNT Libraries Government Documents Department

Segregation in irradiated titanium alloys. [Ion irradiation (2. 1 MeV Ar/sup +/) of Ti-6Al-4V, Ti-8Al-1V-Mo, Ti-3V and Ti-8. 7 Al]

Description: Radiation-induced segregation of V, Al and Mo in ..cap alpha..-phase titanium alloys was investigated. Ion irradiation (2.1-MeV Ar/sup +/) at 650/sup 0/C was used to simulate elevated-temperature neutron irradiation effects. Solute segregation in the near-surface regions of irradiated Ti-6Al-4V, Ti-8Al-1V-1Mo, Ti-3V and Ti-8.71Al was measured with an Auger depth profiling technique. The depth profiles showed evidence of radiation-induced V, Mo and Al segregation toward sample surfaces. This is in accord with a solute size effect. 6 figures.
Date: November 1, 1981
Creator: Wang, Z.; Ayrault, G. & Wiedersich, H.
Partner: UNT Libraries Government Documents Department

An Integrated Hydrogen Production-CO2 Capture Process from Fossil Fuel

Description: The major project objective is to determine the feasibility of using the char from coal and/or biomass pyrolysis, ammonia and CO2 emissions at smokestacks to produce clean hydrogen and a sequestered carbon fertilizer. During this work period, literature review has been completed. The project plan, design and test schedules were made on the basis of discussion with partner in experimental issues. Installation of pilot scale units was finished and major units tests were fully performed. Modification of the pyrolyzer, reformer and gas absorption tank have been done. Integration testing is performing recently. Lab scale tests are in operation phase. The experimental installations are discussed in this paper.
Date: March 15, 2005
Creator: Wang, Z. & Bota, K. B.
Partner: UNT Libraries Government Documents Department

An Intergrated Hydrogen Production-CO2 Capture Process from Fossil Fuel

Description: The major project objective is to determine the feasibility of using the char from coal and/or biomass pyrolysis, ammonia and CO2 emissions at smokestacks to produce clean hydrogen and a sequestered carbon fertilizer. During this work period, the project plan, design and test schedules were made on the basis of discussion with partner in experimental issues. Installation of pilot scale units was finished and major units tests were fully performed. Modification of the pyrolyzer, reformer and gas absorption tank have been done. Integration testing is performing recently. Lab scale tests have been performed. Field tests of char/fertilizer have been conducted.
Date: March 15, 2006
Creator: Wang, Z. & Bota, K. B.
Partner: UNT Libraries Government Documents Department

Design analyses with XRAP for PETRA/HASYLAB beamline filters/windows

Description: The first synchrotron radiation beam line using a 4-m-long undulator at the 12 GeV storage ring PETRA delivers hard x-ray photons usable up to 300 keV. In order to reduce the low energy photon flux and the related thermal load on the beam line optics, graphite, beryllium, aluminum, copper, and iron filters or windows are installed. With a planned upgrade of the undulator, a deflection parameter of K = 2.59 will be reached. The total radiated power of the undulator will then reach (with closed gap) about 15 kW. The central power density will be about 107 W/mrad. Therefore, the design of the filters and windows which interact directly with the white beam becomes a very challenging engineering problem. The heat transfer and thermal stress analyses of PETRA filters and windows are presented. Different filter or window thicknesses, sizes, at different deflection parameters of the undulator, are discussed. Improved filter or window designs are proposed. 5 refs., 4 figs., 8 tabs.
Date: August 1, 1996
Creator: Wang, Z. & Hahn, U.
Partner: UNT Libraries Government Documents Department

Geometry and parameter optimization of PETRA undulator beamline slits

Description: The undulator beamline at the storage ring PETRA of the Hamburger Synchrotronstrahlungslabor HASYLAB delivers hard x-ray photons usable up to 300 keV. The total power of the beam is now up to 7.5 kW with closed gap and 60 mA stored particle beam. After a planned upgrade of the undulator, the power can increase to about 15 kW. The vertical white beam slit for the PETRA undulator beamline is located at about 105 m from the source. The worst case for the slit is when all the power is absorbed in one part of the slit system, which the slits must survive. This paper presents the results from parameter optimization in the worst case. The goal of the optimization is to minimize the maximum temperature of the slits. The geometrical parameters are the cooling hole size, its location from the surface, and the distance between holes. The worst case is found by moving the x-ray beam to all the possible locations. The maximum temperature of an optimized slit that has a two degree angle with the beam is about 192 degrees Celsius. The corresponding thermal stress in the slit is very low. The analysis assumptions, modeling, results, discussion, and conclusion will be given in the paper. 5 refs., 4 figs.
Date: August 1, 1996
Creator: Wang, Z. & Hahn, U.
Partner: UNT Libraries Government Documents Department

Stress level evaluation of thin films under thermal loading from a brazing process

Description: X-ray front end beamline windows are made of thin beryllium foil that is commonly brazed or diffusion bonded onto a copper frame. In the brazing process, due to differences in the thermal expansion coefficient of the beryllium and copper materials, the beryllium film ends up in a state of very high level compression stress after cooling from 700{degrees}C (the brazing temperature) to room temperature. This makes the thin Be foil deform into a dome-shaped structure due to the usual asymmetrical geometry of the window. This paper studies the brazing process using a finite element method and explains the reason for such phenomena. Recommendations are offered for possible improvement in the bonding process of beryllium to the window block.
Date: June 1, 1996
Creator: Wang, Z. & Kuzay, T.M.
Partner: UNT Libraries Government Documents Department

AN INTEGRATED HYDROGEN PRODUCTION-CO2 CAPTURE PROCESS FROM FOSSIL FUEL

Description: The major project objective is to determine the feasibility of using the char from coal and/or biomass pyrolysis, ammonia and CO{sub 2} emissions at smokestacks to produce clean hydrogen and a sequestered carbon fertilizer. During this work period, literature review has been completed. The project plan, design and test schedules were made on the basis of discussion with partner in experimental issues. Installation of pilot scale units was finished and major units tests were fully performed. Modification of the pyrolyzer, reformer and gas absorption tank have been done. Integration testing is performing recently. Lab scale tests are in operation phase. The experimental installations are discussed in this paper.
Date: September 1, 2004
Creator: Wang, Z.; Bota, K.B. & Day, D.
Partner: UNT Libraries Government Documents Department

Corroboration of magnetic forces in US Maglev design

Description: Four System Concept Definition (SCD) contractors to the National Maglev Initiative (NMI) developed conceptual designs of maglev systems in 1991--1992. The objective of the work reported here was to perform independent calculations of the magnetic forces and fields of these four systems to assess the reasonableness'' of the results presented to the government. Commercial computer software was used for computing forces in the system employing nonlinear ferromagnetic materials and for some calculations of induced eddy current effects in finite-sized systems. Other cases required the use of models developed at ANL and verified by experiment, or in a few cases, new computer programs that have not been validated by experiment. The magnetic forces calculated by the contractors were found to be credible in every case evaluated. The stray fields were also found to be in reasonable agreement with those calculated by the contractors, but, for lack of spice, are not reported here.
Date: January 1, 1993
Creator: Coffey, H.; He, J. & Wang, Z.
Partner: UNT Libraries Government Documents Department

Final Report - High-Order Spectral Volume Method for the Navier-Stokes Equations On Unstructured Tetrahedral Grids

Description: The overriding objective for this project is to develop an efficient and accurate method for capturing strong discontinuities and fine smooth flow structures of disparate length scales with unstructured grids, and demonstrate its potentials for problems relevant to DOE. More specifically, we plan to achieve the following objectives: 1. Extend the SV method to three dimensions, and develop a fourth-order accurate SV scheme for tetrahedral grids. Optimize the SV partition by minimizing a form of the Lebesgue constant. Verify the order of accuracy using the scalar conservation laws with an analytical solution; 2. Extend the SV method to Navier-Stokes equations for the simulation of viscous flow problems. Two promising approaches to compute the viscous fluxes will be tested and analyzed; 3. Parallelize the 3D viscous SV flow solver using domain decomposition and message passing. Optimize the cache performance of the flow solver by designing data structures minimizing data access times; 4. Demonstrate the SV method with a wide range of flow problems including both discontinuities and complex smooth structures. The objectives remain the same as those outlines in the original proposal. We anticipate no technical obstacles in meeting these objectives.
Date: December 6, 2012
Creator: Wang, Z J
Partner: UNT Libraries Government Documents Department

An Integrated Hydrogen Producton-CO2 Capture Process from Fossil Fuel

Description: The major project objective is to determine the feasibility of using the char from coal and/or biomass pyrolysis, ammonia and CO2 emissions at smokestacks to produce clean hydrogen and a sequestered carbon fertilizer. During this work period, literature review has been completed. The project plan, design and test schedules were made on the basis of discussion with partner in experimental issues. Installation of pilot scale units was finished and major units tests were fully performed. Modification of the pyrolyzer, reformer and gas absorption tank have been done. Integration testing is performing recently. Lab scale tests have been performed. Field tests of char/fertilizer have been conducted. The experimental results are discussed in this paper.
Date: December 1, 2005
Creator: Wang, Z.; Bota, K.B. & Day, D.
Partner: UNT Libraries Government Documents Department

Present status of computational tools for maglev development

Description: High-speed vehicles that employ magnetic levitation (maglev) have received great attention worldwide as a means of relieving both highway and air-traffic congestion. At this time, Japan and Germany are leading the development of maglev. After fifteen years of inactivity that is attributed to technical policy decisions, the federal government of the United States has reconsidered the possibility of using maglev in the United States. The National Maglev Initiative (NMI) was established in May 1990 to assess the potential of maglev in the United States. One of the tasks of the NMI, which is also the objective of this report, is to determine the status of existing computer software that can be applied to maglev-related problems. The computational problems involved in maglev assessment, research, and development can be classified into two categories: electromagnetic and mechanical. Because most maglev problems are complicated and difficult to solve analytically, proper numerical methods are needed to find solutions. To determine the status of maglev-related software, developers and users of computer codes were surveyed. The results of the survey are described in this report. 25 refs.
Date: October 1, 1991
Creator: Wang, Z.; Chen, S.S. & Rote, D.M.
Partner: UNT Libraries Government Documents Department

Transgenic Medicago truncatula plants obtained from Agrobacterium tumefaciens-transformed roots and Agrobacterium rhizogenes-transformed hairy roots

Description: Article on transgenic Medicago truncatula plants obtained from Agrobacterium tumefaciens-transformed roots and Agrobacterium rhizogenes-transformed hairy roots.
Date: January 9, 2006
Creator: Crane, Cynthia; Wright, Elane; Dixon, R. A. & Wang, Z.-Y. (Zeng-Yu), 1963-
Partner: UNT College of Arts and Sciences

A Hollow Cathode Magnetron (HCM)

Description: A new type of plasma sputtering device, named the hollow cathode magnetron (HCM), has been developed by surrounding a planar magnetron cathode with a hollow cathode structure (HCS). Operating characteristics of HCMs, current-voltage ( I-V ) curves for fixed discharge pressure and voltage-pressure ( V-p ) curves for fixed cathode current, are measured. Such characteristics are compared with their planar magnetron counterparts. New operation regimes, such as substantially lower pressures (0.3 mTorr), were discovered for HCMs. Cathode erosion profiles show marked improvement over planar magnetron in terms of material utilization. The use of HCMs for thin film deposition are discussed.
Date: April 1, 1998
Creator: Cohen, S.A. & Wang, Z.
Partner: UNT Libraries Government Documents Department

Kinetic studies of dry sorent for medium temperature applications. Final report

Description: The purpose of this project is to investigate the fundamental nature of sorbent reactivity and reaction kinetics in the medium temperature range from 600{degrees}F (316{degrees}C) to 1200{degrees}F (649{degrees}C) available in the convective pass of a boiler upstream of the economizer, where dry sorbents are injected to remove SO{sub 2} from the flue gas. Research focuses on the mechanisms of sorbent- flue gas interaction under economizer and hot baghouse conditions utilizing the experimental setup and the results of the first four years of research.
Date: July 12, 1996
Creator: Keener, T.C. & Wang, Z.
Partner: UNT Libraries Government Documents Department

Dielectron production in nucleus {plus} nucleus collisions at 1.05 GeV/nucleon

Description: Measurements of dielectron production in heavy-ion collisions are valuable probes into the dynamics of the collision process. While the hadronic participants of the collision are subject to strong final state interactions, the coupling of the electron-positron pair to the collision medium is electromagnetic. Dielectrons, therefore suffer little rescattering leaving the interaction and can retain information about their production origins, probing even the early stages in the evolution of the collision. The DiLepton Spectrometer (DLS) collaboration`s original measurements of dielectron production established the existence of the signal at Bevalac energies. The 1992- 93 DLS measurements in nucleus+Nucleus collisions at a kinetic beam energy of 1.05 {ital GeV/nucleon} are the subject of this presentation.
Date: June 28, 1996
Creator: Porter, R.J.; Beedoe, S.; Bougteb, M.; Hallman, T. & Wang, Z.F.
Partner: UNT Libraries Government Documents Department

Two-phase flow and transport in the air cathode of proton exchange membrane fuel cells

Description: Two-phase flow and transport of reactants and products in the air cathode of proton exchange membrane (PEM) fuel cells is studied analytically and numerically. Four regimes of water distribution and transport are classified by defining three threshold current densities and a maximum current density. They correspond to first appearance of liquid water at the membrane/cathode interface, extension of the gas-liquid two-phase zone to the cathode/channel interface, saturated moist air exiting the gas channel, and complete consumption of oxygen by the electrochemical reaction. When the cell operates above the first threshold current density, liquid water appears and a two-phase zone forms within the porous cathode. A two-phase, multi-component mixture model in conjunction with a finite-volume-based computational fluid dynamics (CFD) technique is applied to simulate the cathode operation in this regime. The model is able to handle the situation where a single-phase region co-exists with a two-phase zone in the air cathode. For the first time, the polarization curve as well as water and oxygen concentration distributions encompassing both single- and two-phase regimes of the air cathode are presented. Capillary action is found to be the dominant mechanism for water transport inside the two-phase zone. The liquid water saturation within the cathode is predicted to reach 6.3% at 1.4 A/cm{sup 2}.
Date: March 20, 2000
Creator: WANG,Z.H.; WANG,C.Y. & CHEN,KEN S.
Partner: UNT Libraries Government Documents Department

Plasma deposition of high temperature protective coatings

Description: Oxide ceramic films can be made using a vacuum arc based technique in which a metal plasma is formed in an oxygen background, with ion energy controlled by the application of a repetitive pulse bias to the substrate throughout the deposition. High ion energy early in the process produces atomic mixing at the film-substrate interface while lower but optimized ion energy later in the deposition can control the structure and morphology, and films that are adherent and dense can be formed in this way. In recent work we have investigated the formation of films of aluminum-silicon oxide on silicon carbide substrates by mixed aluminum and silicon plasmas produced from separate plasma sources. The Al to Si ratio was controlled by the plasma gun parameters, and the guns were pulsed simultaneously so as to mix the plasma streams before deposition; a magnetic multiple plasma homogenizer device was also used to further blend the two plasmas. Films with Al:Si ratios varying from 2:1 to 8:1 were produced in this study (Al:Si is 3:1 for Mullite), and the oxygen content in the films was controlled by varying the oxygen partial pressure during deposition. Additionally, we have compared some of the characteristics of alumina films plasma deposited on iron aluminide substrates with films produced by e-beam evaporation of Al{sub 2}O{sub 3} using oxygen ion beam assisted deposition onto unheated or heated substrates. Here we outline the film synthesis techniques and describe the characterization results obtained to-date.
Date: April 1, 1996
Creator: Monteiro, O.R.; Wang, Z. & Yu, K.M.
Partner: UNT Libraries Government Documents Department