1,524 Matching Results

Search Results

Advanced search parameters have been applied.

Solvent extraction of cesium by substituted crown ethers

Description: The extraction of alkali metal nitrates by 18-crown-6, 21-crown-7, and 24-crown-8 ethers, bearing cyclohexano, benzo-, t-alkylbenzo, and furano- substituents, in 1,2-dichloroethane has been surveyed. Introduction of a furano substituent onto the macrocyclic ring of 18-crown-6 or 21 crown-7 ethers causes a significant reduction in both extraction efficiency and selectivity. Addition of an additional benzo group to dibenzo-21 -crown-7, to give tribenzo-21 -crown-7, decreases both extraction efficiency and selectivity, whereas addition of one or two additional benzo groups to dibenzo-24-crown-8 increases the extraction efficiency and selectivity for the larger ions Rb+ and Cs{sup +} Detailed equilibrium modeling of the extraction by lipophilic 21 -crown-7 ethers indicates that the addition of t-alkyl substituents onto the benzo groups has only a minor effect on the extraction of cesium nitrate by dibenzo-21 -crown-7 ethers.
Date: December 31, 1996
Creator: Sachleben, R.A.; Deng, Y.; Palmer, D.A. & Moyer, B.A.
Partner: UNT Libraries Government Documents Department

Photochemical studies of alkali halide vapors

Description: Thesis. An apparatus has been constructed for studying the photodissociation of alkali halides to produce excited alkali metal atoms. The key component is a low pressure H/sub 2/ arc continuum uv source. Radiation from this source, modulated by a chopping wheel and analyzed by a monochromator, enters a cell containing the alkali halide vapor. In the appropriate wavelength range, photodissociation occurs to produce the alkali atom in an excited /sup 2/p state, the flourescence from which is detected by a photomultiplier-lock-in amplifier combination. (auth)
Date: August 1, 1973
Creator: Earl, B.L.
Partner: UNT Libraries Government Documents Department

Alkaline flooding injection strategy

Description: The objective of this project is to improved alkali-surfactant flooding methods, and this includes determining the proper design of injection strategy. Several different injection strategies have been used or suggested for recovering heavy oils with surfactant-enhanced alkaline flooding methods. Oil recovery was compared for four different injection strategies: (1) surfactant followed by polymer, (2) surfactant followed by alkaline polymer, (3) alkaline surfactant followed by polymer, and (4) alkali, surfactant, and polymer mixed in a single formulation. The effect of alkaline preflush was also studied under two different conditions. All of the oil recovery experiments were conducted under optimal conditions with a viscous, non-acidic oil from Hepler (KS) oil field. The coreflood experiments were conducted with Berea sandstone cores since field core was not available in sufficient quantity for coreflood tests. The Tucker sand of Hepler field is a Class I fluvial dominated deltaic reservoir, as classified by the Department of Energy, which has been selected as the site of a DOE-sponsored field pilot test.
Date: March 1, 1992
Creator: French, T. R. & Josephson, C. B.
Partner: UNT Libraries Government Documents Department

Surfactant-enhanced alkaline flooding for light oil recovery. [Annual report], 1993--1994

Description: In this report, we present the results of our experimental and theoretical studies in surfactant-enhanced alkaline flooding for light oil recovery. The overall objective of this work is to develop a very cost-effective method for formulating a successful surfactant-enhanced alkaline flood by appropriately choosing mixed alkalis which form inexpensive buffers to obtain the desired pH (between 8.5 and 12.0) for ultimate spontaneous emulsification and ultralow interfacial tension. In addition, we have (1) investigated the effect of surfactant on the equilibrium and transient interfacial tension, (2) investigated the kinetics of oil removal from a silica surface, and (3) developed a theoretical interfacial activity model for determining equilibrium interfacial tension. The results of the studies conducted during the course of this project are presented.
Date: March 1, 1995
Creator: Wasan, D.T.
Partner: UNT Libraries Government Documents Department

Strategies for the cost effective treatment of Oak Ridge legacy wastes

Description: Research and development treatment strategies for treatment or elimination of several Oak Ridge plant liquid, solid, and legacy wastes are detailed in this report. Treatment strategies for volumetrically contaminated nickel; enriched uranium-contaminated alkali metal fluorides; uranium-contaminated aluminum compressor blades; large, mercury-contaminated lithium isotope separations equipment; lithium process chlorine gas streams; high-concentration aluminum nitrate wastes, and high-volume, low-level nitrate wastes are discussed. Research needed to support engineering development of treatment processes is detailed.
Date: March 1, 1998
Creator: Compere, A.L.; Griffith, W.L.; Huxtable, W.P. & Wilson, D.F.
Partner: UNT Libraries Government Documents Department

Structure of borate glasses by Raman spectroscopy

Description: Raman spectra of the alkali borate glasses are presented with emphasis on the implications of detailed frequency shifts and line shapes. The results are interpreted on a rather complicated three-level hierarchy of glass structures which include boron-oxygen polyhedra, topologically closed rings of polyhedra, and larger scale interconnected clusters of alkali-rich and alkali-poor structures. Both the model and the argument are deliberately vague. The borate glasses appear to be highly disordered materials with a size scale such that no presently available tool gives a really clear view of the structural detail.
Date: January 1, 1977
Creator: White, W.B.; Brawer, S.A.; Furukawa, T. & McCarthy, G.J.
Partner: UNT Libraries Government Documents Department

Lines in the spectrum of /sup 7/LiH (5177 to 8643 A)

Description: The emission spectra of the A /sup 1/..sigma../sup +/ - X /sup 1/..sigma../sup +/ bands of /sup 7/LiH were photographed in the 5177 A to 8643 A region in the fourth, fifth, and sixth order of a 3.4 meter Ebert Spectrograph with reciprocal dispersions of 2.2, 1.7, and 1.4 A/mm. The measured lines in the spectra of /sup 7/LiH in the region 5177 to 8643 A are given. Similar spectra for the region 4728 to 5298 A are given in the companion report (COO-2326-19). In the small region of overlap (5177 to 5298 A), the line positions are in good agreement, but these are felt to be the more accurate.
Date: January 1, 1979
Creator: Orth, F.B. & Stwalley, W.C.
Partner: UNT Libraries Government Documents Department

Atomic polar tensors and acid-base properties of metal-oxide building blocks

Description: The sensitivity of the atomic polar tensor to compositional substituents is reported for the alkali silicate series. Rotational invariants, effective atomic charge (GAPT) and charge normalized anisotropy and dipole ({alpha}{sub n} and {gamma}{sub n}) are used to characterize the charge distribution and chemical environment of the atomic sites. Comparison of {alpha}{sub n} and {gamma}{sub n} with a series of known Bronsted and Lewis acids and bases suggests that these rotational invariants may act as indicators for metal-oxide site acidities. Basis set and electron correlation particularly affect the determined effective charge, but show minimal effect on {alpha} and {gamma} quantities.
Date: February 1, 1993
Creator: Ferris, K. F.
Partner: UNT Libraries Government Documents Department

Aqueous electrolyte modeling in ASPEN PLUS{trademark}

Description: The presence of electrolytes in aqueous solutions has long been recognized as contributing to significant departures from thermodynamic ideality. The presence of ions in process streams can greatly add to the difficulty of predicting process behavior. The difficulties are increased as temperatures and pressures within a process are elevated. Because many chemical companies now model their processes with chemical process simulators it is important that such codes be able to accurately model electrolyte behavior under a variety of conditions. Here the authors examine the electrolyte modeling capability of ASPEN PLUS{trademark}, a widely used simulator. Specifically, efforts to model alkali metal halide and sulfate systems are presented. The authors show conditions for which the models within the code work adequately and how they might be improved for conditions where the simulator models fail.
Date: February 1, 1995
Creator: Bloomingburg, G. F.; Simonson, J. M.; Moore, R. C.; Mesmer, R. E. & Cochran, H. D.
Partner: UNT Libraries Government Documents Department

Phase behavior and oil recovery investigations using mixed and alkaline-enhanced surfactant systems

Description: The results of an evaluation of different mixed surfactant and alkaline-enhanced surfactant systems for enhanced oil recovery are described. Several mixed surfactant systems have been studies to evaluate their oil recovery potential as well as improved adaptability to different ranges of salinity, divalent ion concentrations, and temperature. Several combinations of screening methods were used to help identify potential chemical formulations and determine conditions where particular chemical systems can be applied. The effects of different parameters on the behavior of the overall surfactant system were also studied. Several commercially available surfactants were tested as primary components in the mixtures used in the study. These surfactants were formulated with different secondary as well as tertiary components, including ethoxylated and non-ethoxylated sulfonates and sulfates. Improved salinity and hardness tolerance was achieved for some of these chemical systems. The salinity tolerance of these systems were found to be dependent on the molecular weight, surfactant type, and concentration of the surfactant components.
Date: March 1, 1992
Creator: Llave, F. M.; Gall, B. L.; French, T. R.; Noll, L. A. & Munden, S. A.
Partner: UNT Libraries Government Documents Department

Response of alkali halide scintillators to neutrons from 5 to 100 MeV

Description: The response of three alkali halide scintillator`s to neutrons in the range 5 to 100 MeV was investigated with the spallation neutron source at LAMPF/WNR. Scintillating crystals were Nal(Tl), Kl(Tl) and Csl(Tl), each 2.5 cm in diameter and 1.2 cm thick. Pulse shapes that depend on particle type were observed for Nal(Tl) and Csl(Tl) but not for Kl(Tl). Pulse height spectra for are reported as a function of neutron energy, and, where pulse shape discrimination was observed, for individual charged-particle groups.
Date: July 1, 1994
Creator: Bartle, C. M. & Haight, R. C.
Partner: UNT Libraries Government Documents Department

Measurement of alkali-vapor emission from pressurized fluidized-bed combustion of Illinois coals

Description: Two Illinois Herrin No. 6 coals and one Illinois Springfield No. 5 coal were separately combusted in a laboratory-scale (15-cm dia) pressurized fluidized-bed combustor (PFBC) combined with an alkali sorber. These coals were combusted in a fluidized bed of Tymochtee dolomite at temperatures ranging from 910 to 950{degree}C and a system pressure of 9.2 atm absolute. Alkali-vapor emission (Na and K) in the PFBC flue gas was determined by the analytical activated-bauxite sorber bed technique developed at Argonne National Laboratory. The test results showed that sodium is the major alkali-vapor species present in the PFBC flue gas, and that the level of sodium-vapor emission increases linearly with both Na and Cl contents in the coals. This suggests that the sodium-vapor emission results from direct vaporization of NaCl present in the coals. The measured alkali-vapor concentration (Na + K), 67 to 190 ppbW, is more than 2.5 times greater than the allowable alkali limit of 24 ppb for an industrial gas turbine. Combusting these coals in a PFBC for power generation may require developing a method to control alkali vapors.
Date: April 1, 1993
Creator: Lee, S. H. D.; Teats, F. G.; Swift, W. M. & Banerjee, D. D.
Partner: UNT Libraries Government Documents Department

Novel macrocyclic carriers for proton-coupled liquid membrane transport. Progress report, December 1, 1992--November 30, 1993

Description: Methods were devised for preparing cryptands (bicyclic ligands). Effects of addition of hydrophobic side chains on crown ethers used in separation systems; crowns containing side chains of varying lengths were studied in back extraction and dual module hollow fiber membrane separation experiments. Thermodynamics of macrocycle-cation reactions were studied at high temperature. Effort was made on computer (molecular mechanics) modeling of macrocycle binding of alkali metal ions in gas phase. 8 figs, 26 refs.
Date: August 1, 1993
Creator: Lamb, J. D.; Bradshaw, J. S.; Shirts, R. B. & Izatt, R. M.
Partner: UNT Libraries Government Documents Department

Anion-exchange resin-based desulfurization process. Quarterly technical progress report, April 1, 1992--June 30, 1992

Description: The University of Tennessee Space Institute (UTSI) has contracted to further develop its anion-exchange, resin-based desulfurization concept to desulfurize alkali metal sulfates. From environmental as well as economic viewpoints, it is necessary to remove soluble sulfates from the wastes created by flue gas desulfudization systems. In order to do this economically, a low-cost desulfurization process for spent sorbents is necessary. UTSl`s anion exchange resin-based desulfudization concept is believed to satisfy these requirements. We have nearly completed the process variables study in which we have evaluated the effects of seven major process variables. At present, we are analyzing the data using the fixed bed math model used in our earlier study. We have also initiated the batch mode resin regeneration experiments to identity optimum conditions for the fixed bed regeneration. Similarly, we are also continuing with our efforts to determine the trade-off between the solution concentration and the evaporation/concentration load.
Date: September 1, 1992
Creator: Sheth, A. C.; Strevel, S. D. & Dharmapurikar, R.
Partner: UNT Libraries Government Documents Department

Mechanism of surface enrichment and adhesion of coal combustion particulates. First quarterly report, February 1987

Description: During the first three months of the project, the emphasis has been on the following areas: (1) Design of the apparatus and development of the experimental techniques for the controlled adsorption of alkali on potential additives. (2) Development of techniques for the quantitative and qualitative characterization of alkali distribution in small additive particles using Scanning Auger Spectroscopy. The preliminary experiments of the adsorption of NaCl on bauxite shows a very non-uniform distribution of alkali on the substrate. The chorine appears to undergo some form of chemical interaction with alumina surface. An optimum set of electron beam parameters are found for which the alkali distribution is stable during Auger Spectroscopy and depth profiling by ion milling.
Date: December 31, 1987
Creator: Shadman, F.; Peterson, T. W.; Wendt, J. O. L. & Punjak, W. A.
Partner: UNT Libraries Government Documents Department

Synergistic capture mechanisms for alkali and sulphur species for combustion. Quarterly report No. 9, September--November 1992

Description: The reaction of a porous particle with a gaseous species in a confined flow environment, is a fairly complex process whose complete analysis needs consideration of a large number of physical and chemical rate processes. It involves mass transport of gaseous reactants and products in the surrounding gas phase, mass transport in the interior of the porous particle, reaction on the internal and external surfaces of the particle and effects of structural changes that the particle undergoes as reaction proceeds. The problem of solving a classical diffusion reaction equation is further complicated with the difficulty in the choice of boundary conditions at the outer particle radius. Unlike the case of fixed bed reactors where the outer gas phase bulk concentration assumes a steady profile, and hence constant relative to the particle, in a continuous flow process described by our reactor, the particles `see` a gas phase alkali concentration and bulk phase temperature that changes as the particle moves down the flowfield. The model of capture presented here consist of a series of first order ordinary differential equations of the initial value type. As was stated earlier, an eularian approach is adopted in this section. The capture equation is first formulated as a species conservation equation in the fluid phase. Auxiliary equations of particle number density, temperature profile, and the ideal gas law are then combined with conservation equation to solve for the alkali gas phase concentration profile along the axial length of the combustor. Assumptions that were discussed in earlier, also apply here. Unless otherwise stated, all symbols here are as have been used throughout the body of the text.
Date: December 31, 1992
Creator: Peterson, T. W.; Shadman, F.; Wendt, J. O. L. & Mwabe, P. O.
Partner: UNT Libraries Government Documents Department

Synergistic capture mechanisms for alkali and sulphur species for combustion. Quarterly report No. 7, March--May 1992

Description: Table 5 shows a total sodium capture of 97 % for no chlorine case and 75 % for excess chlorine case. Similar results are shown for the water insoluble capture; 78 % for the no chlorine case against 48 % capture for excess chlorine case. Figure 15 shows comparative plate by plate mass loadings for Sample 244 and sample 303, while Figure 11 shows the partition of fraction oxides in the same impacters. Fraction mass distribution of the sampled kaolinite is shown in Figure 12, with a corresponding fraction mass distribution of water soluble sodium oxide is shown in Figure 13. The fraction oxide mass distribution of the 22% water soluble sodium from the no chlorine case (Figure 18), shows similar distribution to the kaolinite fraction mass distribution (Figure 12). This suggests that the water soluble sodium oxide in the absence of chlorine was probably capillary condensed or it was reacted sodium oxide that is water soluble. Surface condensation is unlikely as there would have been a shift to the smaller size range. This argument had been shown by Neville et al (1985) that condensation on its own would result in the bulk of the mass being found in the submicron size range. The fraction oxide mass distribution of the 52% water soluble sodium oxide, from the excess chlorine correlate weakly with the kaolinite fraction mass distribution, instead, there is a clear shift towards the fume size range of the after filter and stage 8. This indicates that the water soluble sodium oxide, from excess chlorine case, was predominantly uncaptured sodium. Presence of chlorine in this case reduced sodium capture by 30%.
Date: December 31, 1992
Creator: Peterson, T. W.; Shadman, F.; Wendt, J. O. L. & Mwabe, P. O.
Partner: UNT Libraries Government Documents Department

Integrated Low Emissions Cleanup system for direct coal fueled turbines (moving bed, fluid contactor/ceramic filter). Twenty-second quarterly status report, January--March 1993

Description: The United States Department of Energy, Morgantown Energy Research Center (DOE/METC), is sponsoring the development of direct coal-fired turbine power plants as part of their Heat Engines program. A major technical challenge remaining for the development of the direct coal-fired turbine is high-temperature combustion gas cleaning to meet environmental standards for sulfur oxides and particulate emissions, as well as to provide acceptable turbine life. The Westinghouse Electric Corporation, Science & Technology Center, is evaluating two Integrated Low Emissions Cleanup (ILEC) concepts that have been configured to meet this technical challenge: A baseline ceramic barrier filter ILEC concept, and a fluidized bed ILEC concept. These ILEC concepts simultaneously control sulfur, particulate, and alkali contaminants in the high-pressure combustion gases at turbine inlet temperatures up to 2300{degrees}F. This document reports the status of a program in the nineteenth quarter to develop this ILEC technology for direct coal-fired turbine power plants.
Date: October 1, 1993
Creator: Newby, R. A.; Alvin, M. A.; Bachovchin, D. M.; Yang, W. C.; Smeltzer, E. E. & Lippert, T. E.
Partner: UNT Libraries Government Documents Department

Predictive modelling of boiler fouling. Quarterly technical progress report, January 1, 1992--March 31, 1992

Description: In this reporting period, efforts were initiated to supplement the comprehensive flow field description obtained from the RNG-Spectral Element Simulations by incorporating, in a general framework, appropriate modules to model particle and condensable species transport to the surface. Specifically, a brief survey of the literature revealed the following possible mechanisms for transporting different ash constituents from the host gas to boiler tubes as deserving prominence in building the overall comprehensive model: (1) Flame-volatilized species, chiefly sulfates, are deposited on cooled boiler tubes via the mechanism of classical vapor diffusion. This mechanism is more efficient than the particulate ash deposition, and as a result there is usually an enrichment of condensable salts, chiefly sulfates, in boiler deposits; (2) Particle diffusion (Brownian motion) may account for deposition of some fine particles below 0. 1 mm in diameter in comparison with the mechanism of vapor diffusion and particle depositions, however, the amount of material transported to the tubes via this route is probably small. (3) Eddy diffusion, thermophoretic and electrophoretic deposition mechanisms are likely to have a marked influence in transporting 0.1 to 5{mu}m particles from the host gas to cooled boiler tubes; (4) Inertial impaction is the dominant mechanism in transporting particles above 5{mu}m in diameter to water and steam tubes in pulverized coal fired boiler, where the typical flue gas velocity is between 10 to 25 m/s. Particles above 10{mu}m usually have kinetic energies in excess of what can be dissipated at impact (in the absence of molten sulfate or viscous slag deposit), resulting in their entrainment in the host gas.
Date: December 1, 1992
Partner: UNT Libraries Government Documents Department

Method for the Removal of Ultrafine Particulates from an Aqueous Suspension

Description: A method of separating ultra-fine particulate from an aqueous suspension such as a process stream or a waste stream. The method involves the addition of alkali silicate and an organic gelling agent to a volume of liquid, from the respective process or waste stream, to form a gel. The gel then undergoes syneresis to remove water and soluble salts from the gel-containing the particulate, thus, forming a silica monolith. The silica monolith is then sintered to form a hard, nonporous waste form.
Date: March 5, 1999
Creator: Chaiko, David J.; Kopasz, John P. & Ellison, Adam J. G.
Partner: UNT Libraries Government Documents Department

Process for extracting technetium from alkaline solutions

Description: This invention relates generally to a process for extracting technetium from nuclear wastes and more particularly to a process for extracting technetium from alkaline waste solutions containing technetium and high concentrations of alkali metal nitrates. A process for extracting technetium values from an aqueous alkaline solution containing at least one alkali metal hydroxide and at least one alkali metal nitrate comprises the steps of: contacting the aqueous alkaline solution with a solvent consisting of a crown ether in a diluent, the diluent being a water-immiscible organic liquid in which the crown ether is soluble, for a period of time sufficient to selectively extract the technetium values from the aqueous alkaline solution into the solvent; separating the solvent containing the technetium values from the aqueous alkaline solution; and stripping the technetium values from the solvent by contacting the solvent with water.
Date: December 31, 1994
Creator: Moyer, B.A.; Sachleben, R.A. & Bonnesen, P.V.
Partner: UNT Libraries Government Documents Department

Theoretical density of lithium aluminate updated

Description: The ''handbook'' density for LiAlO/sub 2/ is 2.55 g/cc. Recent data show that it should be revised to 2.62 g/cc. In the future densities reported as percent of theoretical should be based on 2.62 g/cc as being 100 percent. Values quoted on this basis will be more realistic. In order to avoid confusion it will be necessary to state which number percent of theoretical density are based upon--that is, ''2.62 g/cc = 100 percent,'' or ''2.55 g/cc = 100 percent.'' For the convenience of those working directly with the material, a conversion chart is included along with a table which gives density (g/cc) versus percent density based on 2.62 g/cc.
Date: January 12, 1966
Creator: Gurwell, W. E.
Partner: UNT Libraries Government Documents Department

High temperature alkali corrosion of ceramics in coal gas. Quarterly progress report No. 6, December 1, 1992--February 28, 1993

Description: The high temperature alkali corrosion kinetics of SiC have been systematically investigated from 950 to 1100{degrees}C at 0.63 vol % alkali vapor concentration. The corrosion rate in the presence of alkaliis approximately 10{sup 4} to 10{sup 5} times faster than the oxidation rate of SiC in air. The activation energy associated with the alkali corrosion is 406 kJ/mol, indicating a highly temperature-dependent reaction rate. The rate-controlling step of the overall reaction is likely to be the dissolution of silica in the sodium silicate liquid, based on the oxygen diffusivity data.
Date: February 24, 1992
Creator: Pickrell, G. R.; Sun, T. & Brown, J. J.
Partner: UNT Libraries Government Documents Department