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The development of precipitated iron catalysts with improved stability

Description: The objective of this program is to identify the chemical principles governing the deactivation of precipitated iron catalysts during Fischer-Tropsch synthesis and to use these chemical principles in the design of catalysts suitable for slurry reactors. The performance targets are 88% CO+H{sub 2} conversion with less than 1% deactivation/day for 1 month and a methane and ethane selectivity of no more than 7% (based on hydrocarbons and oxygenates only) at a space velocity of at least 2 normal li… more
Date: May 6, 1992
Creator: Abrevaya, H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Sodium Fluozirconate Precipitation Process for Zirconium Fuels. Part 1. Laboratory Development

Description: Precipitation, evaporation, and extraction feed preparation conditions are established for the removal of zirconium and fluoride from fuel dissolver product solutions by the addition of sodium formate. A sparingly soluble complex fluozirconate is formed. Ninety-five to 99% of the zirconium and fluoride is separated from the uranium losses of 0.1% or less. Chemical material balances, based on experimental data, were developed for two flowsheets. In one flowsheet, sufficient nitric acid is added … more
Date: May 15, 1962
Creator: Newby, B. J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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HEAD-END TREATMENT OF LOW LEVEL WASTES PRIOR TO FOAM SEPARATION

Description: Calcium-magnesium precipitation apparatus was used to reduce the concentrations of these elements in ORNL tap water, used as a substitute for waste water of low level of radioactivity, prior to strontium removal by foam separation. With and without alkali and flocculator chambers and with a stirred sludge of ratio height to diameter equal to 1/1 to ~4/1, use of 5 x 10/sup -3/ M each of NaOH and Na/sub 2/CO/sub 3/ and 2 ppm Fe/sup 3+/ reduced the dissolved Ca + Mg concentrations to 1 to 2 ppm as… more
Date: May 29, 1962
Creator: Schonfeld, E. & Davis, W. Jr.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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LABORATORY DEVELOPMENT OF A CARRIER-PRECIPITATION PROCESS FOR THE RECOVERY OF STRONTIUM FROM PUREX WASTES

Description: Strontium recovery from Purex 1WW was investigated with simulated feeds and tracer activities. Initial experiments demonstrated recovery of over 70% of the strontium by sulfate precipitation from partially neutralized 1WW by either increasing the sulfate concentration to about 3 M or by adding carriers such as lead. Precipitation of iron was avoided by addition of one or more moles of tartrate per two moles of iron. Precipitation at elevated temperatures and addition of lead after pH adjustment… more
Date: May 1, 1961
Creator: Bray, L.A. & Van Tuyl, H.H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

The development of precipitated iron catalysts with improved stability

Description: The objective of this program is to identify the chemical principles governing the deactivation of precipitated iron catalysts during Fischer-Tropsch synthesis and to use these chemical principles in the design of catalysts suitable for slurry reactors. The performance targets are 88% CO+H{sub 2} conversion with less than 1% deactivation/day for 1 month and a methane and ethane selectivity of no more than 7% (based on hydrocarbons and oxygenates only) at a space velocity of at least 2 normal li… more
Date: May 6, 1992
Creator: Abrevaya, H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

The development of precipitated iron catalysts with improved stability

Description: The objective of this program is to identify the chemical principles governing the deactivation of precipitated iron catalysts during Fischer-Tropsch synthesis and to use these chemical principles in the design of catalysts suitable for slurry reactors. The performance targets are 88% CO+H{sub 2} conversion with less than 1% deactivation/day for 1 month and a methane and ethane selectivity of no more than 7% (based on hydrocarbons and oxygenates only) at a space velocity of at least 2 normal li… more
Date: May 6, 1992
Creator: Abrevaya, H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

COATING OF UO$sub 2$ PARTICLES WITH BeO BY SOLUTION METHODS

Description: Spherical particles of beryllium oxide containing and enclosing UO/sub 2/ particles (-1O micron) were prepared by dispersing a suspension of UO/sub 2/ in a concentrated viscous solution of a basic beryllium saIt in a liquid organic medium, drying, and firing. The spheres produced were porous and would require densification to make the beryllium oxide protective to the UO/sub 2/. Precipitation of beryllium hydroxide or carbonate on UO/sub 2/ particles suspended in solutions of beryllium salts un… more
Date: May 1, 1962
Creator: McDowell, W.J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

The development of precipitated iron catalysts with improved stability

Description: The objective of this program is to identify the chemical principles governing the deactivation of precipitated iron catalysts during Fischer-Tropsch synthesis and to use these chemical principles in the design of catalysts suitable for slurry reactors. The performance targets are 88% CO+H{sub 2} conversion with less than 1% deactivation/day for 1 month and a methane and ethane selectivity of no more than 7% (based on hydrocarbons and oxygenates only) at a space velocity of at least 2 normal li… more
Date: May 6, 1992
Creator: Abrevaya, H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

The development of precipitated iron catalysts with improved stability

Description: The objective of this program is to identify the chemical principles governing the deactivation of precipitated iron catalysts during Fischer-Tropsch synthesis and to use these chemical principles in the design of catalysts suitable for slurry reactors. The performance targets are 88% CO+H{sub 2} conversion with less than 1% deactivation/day for 1 month and a methane and ethane selectivity of no more than 7% (based on hydrocarbons and oxygenates only) at a space velocity of at least 2 normal li… more
Date: May 6, 1992
Creator: Abrevaya, H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

The development of precipitated iron catalysts with improved stability

Description: The objective of this program is to identify the chemical principles governing the deactivation of precipitated iron catalysts during Fischer-Tropsch synthesis and to use these chemical principles in the design of catalysts suitable for slurry reactors. The performance targets are 88% CO+H{sub 2} conversion with less than 1% deactivation/day for 1 month and a methane and ethane selectivity of no more than 7% (based on hydrocarbons and oxygenates only) at a space velocity of at least 2 normal li… more
Date: May 6, 1992
Creator: Abrevaya, H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Coprecal: materials accounting in the modified process

Description: This report presents the design and evaluation of an advanced materials accounting system for a uranium-plutonium nitrate-to-oxide coconversion facility based on the General Electric Coprecal process as modified by Savannah River Laboratory and Plant and DuPont Engineering. The modifications include adding small aliquot tanks to feed the process and reconfiguring the calciner filter systems. Diversion detection sensitivities for the modified Coprecal process are somewhat better than the origina… more
Date: May 1, 1980
Creator: Dayem, H.A.; Kern, E.A. & Shipley, J.P.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

The role of biotechnology in the treatment of geothermal residual sludges

Description: Power plants which use geothermal heat to generate electric power produce a residual sludge in large quantities. This material precipitates from supersaturated brines and contains toxic metals, some of which are present in concentrations exceeding the non hazardous waste disposal regulations. Disposal of this waste as hazardous waste is costly. Work in this laboratory has shown that a biotreatment of the geothermal waste in which toxic metal resistant acidophilic organisms are used can serve as… more
Date: May 1, 1988
Creator: Premuzic, E.T. & Lin, M.S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Characterization and Mechanical Properties of Nanoscale Precipitates in Modified Al-Si-Cu Alloys Using Transmission Electron Microscopy and 3D Atom Probe Tomography.

Description: Among the commercial aluminum alloys, aluminum 319 (Al-7wt%Si-4wt%Cu) type alloys are popularly used in automobile engine parts. These alloys have good casting characteristics and excellent mechanical properties resulting from a suitable heat treatment. To get a high strength in the 319 type alloys, grain refining, reducing the porosity, solid solution hardening, and precipitation hardening are preferred. All experimental variables such as solidification condition, composition, and heat treatme… more
Date: May 2007
Creator: Hwang, Junyeon
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Study of Substituted Benzenesulfonate-Containing Layered Double Hydroxides and Investigation of the Hexamethylenetetramine Route of LDH Synthesis

Description: Benzenesulfonates, para-substituted with amine, chloride and methyl groups were successfully incorporated into layered double hydroxides of two different compositions, 2:1 Mg-Al LDH and 2:1 Zn-Al LDH. These parent materials were also doped with small amounts of nickel and the differences in the two systems were studied. The hexamethylenetetramine route of layered double hydroxide synthesis was investigated to verify if the mechanism is indeed homogeneous. This included attempting preparation of… more
Date: May 2007
Creator: Ambadapadi, Sriram
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Thermodynamic and Mass Balance Analysis of Expansive Phase Precipitation in Saltstone

Description: This report assesses the potential for future precipitation of expansive phases that could cause fracturing in saltstone. It examines the equilibrium case using The Geochemist's Workbench{reg_sign} reaction path model. The scenarios simulated examine the effects of different possible infiltrating fluids, different saltstone formulations, and different amounts of minerals available for reaction. Mineralogy of the vault cement and saltstone were estimated using reported chemical compositions of e… more
Date: May 1, 2008
Creator: Fletcher, D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Linking reaction, transport, and hydrological parameters inunsaturated fractured rock: toughreact implementation andapplication

Description: Modeling coupled water-gas-rock interactions in unsaturated fractured rock requires conceptual and numerical model considerations beyond those developed for saturated porous media. This paper focuses on the integration of the geological and hydrological parameters into the calculation of reactive-transport parameters and the feedback of mineral precipitation/dissolution to flow and transport. These basic relations have been implemented in the reactive transport code TOUGHREACT (Xu et al., 2003)… more
Date: May 15, 2003
Creator: Sonnenthal, Eric; Spycher, Nicolas & Xu, Tianfu
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Shape-selective catalysts for Fischer-Tropsch chemistry : iron-containing particulate catalysts. Activity report : January 1, 2001 - December 31, 2004.

Description: Argonne National Laboratory is carrying out a research program to create, prepare, and evaluate catalysts to promote Fischer-Tropsch (FT) chemistry--specifically, the reaction of hydrogen with carbon monoxide to form long-chain hydrocarbons. In addition to needing high activity, it is desirable that the catalysts have high selectivity and stability with respect to both mechanical strength and aging properties. It is desired that selectivity be directed toward producing diesel fraction component… more
Date: May 12, 2006
Creator: Cronauer, D. & Engineering, Chemical
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

THERMODYNAMIC AND MASS BALANCE ANALYSIS OF EXPANSIVE PHASE PRECIPITATION IN SALTSTONE

Description: This report assesses the potential for future precipitation of expansive phases that could cause fracturing in saltstone. It examines the equilibrium case using The Geochemist's Workbench{reg_sign} reaction path model. The scenarios simulated examine the effects of different possible infiltrating fluids, different saltstone formulations, and different amounts of minerals available for reaction. Mineralogy of the vault cement and saltstone were estimated using reported chemical compositions of e… more
Date: May 6, 2008
Creator: Denham, M
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Geothermal research at the Puna Facility

Description: Chemical analyses were conducted on the flocculated silica samples obtained during previous field experiments at HGP-A on both flashed and unflashed brines to determine the composition of the recovered silica for specific constituents of the brine which seem to often be entrapped in the silica during the flocculation process. Metals added as flocculants to the brine were also analyzed in order to evaluate the ease or difficulty with which these can be removed from the precipitated silica under … more
Date: May 1, 1986
Creator: Chen, B.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Precipitation hardening in Fe--Ni base austenitic alloys

Description: The precipitation of metastable Ni/sub 3/X phases in the austenitic Fe--Ni-base alloys has been investigated by using various combinations of hardening elements, including Ti, Ta, Al, and Nb. The theoretical background on the formation of transition precipitates has been summarized based on: atomic size, compressibility, and electron/atom ratio. A model is proposed from an analysis of static concentration waves ordering the fcc lattice. Ordered structure of metastable precipitates will change f… more
Date: May 1, 1979
Creator: Chang, K.M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Chemistry and materials in geothermal systems

Description: The development of a geothermal fluid, from its origin as meteoric water precipitating on the earth's surface, as it flows through the soils and rocks of geological formations, to the point where it returns to the surface as a hot spring, geyser, well, etc. is traced. Water of magmatic origin is also included. The tendency of these hydrothermal fluids to form scales by precipitation of a portion of their dissolved solids is noted. A discussion is presented of types of information required for m… more
Date: May 1, 1979
Creator: Miller, R. L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Evaluation of Climate Change Impacts on Wetland Vegetation in the Dunhuang Yangguan National Nature Reserve in Northwest China Using Landsat Derived NDVI

Description: This article uses 41 Landsat images between 1988 and 2016 to calculate the normalized difference vegetation indices (NVDIs) of the wetland vegetation at Xitugou (XTG) and Wowachi (WWC) inside the Dunhuang Yangguan National Nature Reserve in northwest China in order to assess the impacts of climate change on wetland vegetation.
Date: May 10, 2018
Creator: Pan, Feifei; Xie, Jianping; Lin, Juming; Zhao, Tingwei; Ji, Yongyuan; Hu, Qi et al.
Item Type: Refine your search to only Article
Partner: UNT College of Liberal Arts & Social Sciences
open access

Puff-plume atmospheric deposition model for use at SRP in emergency-response situations

Description: An atmospheric transport and diffusion model developed for real-time calculation of the location and concentration of toxic or radioactive materials during an accidental release was improved by including deposition calculations.
Date: May 1, 1981
Creator: Garrett, A. J. & Murphy, C. E. Jr.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Strontium fluoride flowsheet development studies for the waste packaging program

Description: It was demonstrated that the modified version of the Martin flowsheet can produce SrF/sub 2/ of acceptable quality using a simulated feed of the same composition as the anticipated packaging plant feed. By careful control of operating conditions, strontium losses in the process can be reduced to an acceptable level. Using a nonrepresentative radioactive feed (which contained impurities not present in the simulated feed) high strontium losses were encountered in the feed purification step, altho… more
Date: May 25, 1972
Creator: Fullam, H.T. & Bray, L.A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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