110 Matching Results

Search Results

Advanced search parameters have been applied.

(Photoexcited charge pair escape and recombination)

Description: Progress in four research areas on this project are summarized under the following topics: (1) Geminate charge pair recombination in hexane; (2) Fast current measurements resulting from excitation of charge transfer (CT) states; (3) Measurement of the dipole moment of excited states by DC conductivity; and (4) Charge separation at macroscopic interfaces between electron donor and acceptor solids. In a final section, personnel who have contributed to the project during the past budget period are described.
Date: January 1, 1990
Creator: Braun, C.L.
Partner: UNT Libraries Government Documents Department

Condensing curves for a number of mixed-hydrocarbon working fluids

Description: Condensing curves are presented for a number of two-component mixed hydrocarbon working fluids which are potentially usable in binary geothermal cycles. Performance of geothermal thermodynamic cycles incorporating these fluids has been evaluated under separate cover; two figures summarizing the results of those evaluations have been included here for continuity. The purpose of this report is: first, to document the condensing curves which were used in the mixed fluid cycle analyses, and second, to provide background useful in the preliminary evaluation of heat rejection systems for advanced geothermal electric power plants utilizing mixed hydrocarbon working fluids. Some concluding remarks are presented.
Date: July 1, 1981
Creator: Denmuth, O.J.
Partner: UNT Libraries Government Documents Department

Process and analytical studies of enhanced low severity co-processing using selective coal pretreatment

Description: This report describes progress on research during the 12th and final quarter of this contract dealing with applications of coal pretreatment techniques in coal/oil co-processing and direct hydroliquefaction. The overall objectives of the project are to investigate various coal pretreatment techniques and to determine the effect of these pretreatment procedures on the reactivity of the coal. Reactivity enhancement will be evaluated under both direct hydroliquefaction and co-processing conditions. Coal conversion utilizing low rank coals and low severity conditions (reaction temperatures generally less than 350{degree}C) is the primary focus of the liquefaction experiments, as it is expected that the effect of pretreatment conditions and the attendant reactivity enhancement will be greatest for these coals and at these conditions.
Date: January 1, 1991
Creator: Baldwin, R.M.; Gaur, S. & Miller, R.L.
Partner: UNT Libraries Government Documents Department

Process and analytical studies of enhanced low severity co-processing using selective coal pretreatment

Description: This report describes progress on research during the seventh quarter of this contract dealing with applications of coal pretreatment techniques in coal hydroliquefaction. The objectives of the project are to investigate various coal pretreatment techniques and to determine the effect of these pretreatment procedures on the reactivity of the coal. Reactivity enhancement will be evaluated under both direct hydroliquefaction and co-processing conditions. Coal conversion utilizing low rank coals and low severity conditions (reaction temperatures generally less than 350 {degrees}C) are the primary focus of the liquefaction experiments, as it is expected that the effect of pretreatment conditions and the attendant reactivity enhancement will be greatest for these coals at these conditions.
Date: January 1, 1990
Creator: Baldwin, R.M. & Miller, R.L.
Partner: UNT Libraries Government Documents Department

Thermal and hydraulic performance tests of a sieve-tray direct-contact heat exchanger vaporizing pure and mixed-hydrocarbon Rankine-cycle working fluids

Description: Experiments investigating a sieve-tray direct-contact heat exchanger were conducted at the Raft River Geothermal Test Site in southeastern Idaho using the 60-kW Mobile Heat Cycle Research Facility operating in the thermal loop mode (without a turbine). Isobutane, propane, and several hydrocarbon mixtures were heated and boiled in the direct-contact column, which is approx. 12 in. in diameter and 19-1/2 ft. high, using the energy from a 280/sup 0/F geothermal resource. Using pure fluids, isobutane or propane, the column operated much as intended, with 17 trays used for preheating and one or two accomplishing the boiling. For the pure fluids, individual tray efficiencies were found to be 70% or higher for preheating, and close to 100% for boiling; column pinch points were projected to be well under 1/sup 0/F with some runs reaching values as low as approx. 0.02/sup 0/F. Maximum geofluid throughputs for the isobutane tests corresponded roughly to the terminal rise velocity of a 1/32 in. working fluid droplet in geofluid. Boiling was found to occur in as many as 12 trays for the mixtures having the highest concentrations of the minor component, with overall efficiencies in the boiling section estimated on the order of 25 or 30%. Preheating tray efficiencies appeared to be fairly independent of working fluid, with pinch points ranging from as low as approx. 0.03/sup 0/F for a 0.95 isobutane/0.05 hexane mixture to approx. 2.3/sup 0/F for a 0.85 isobutane/0.05 hexane mixture. Column operation was noticeably less stable for the mixtures than for the pure fluids, with maximum throughputs dropping to as low as 40 to 50% of those for the pure fluids.
Date: August 1, 1983
Creator: Mines, G.L.; Demuth, O.J. & Wiggins, D.J.
Partner: UNT Libraries Government Documents Department

Thermal and hydraulic performance of a sieve-tray direct-contact heat exchanger

Description: Experiments investigating the thermal and hydraulic performance of a sieve tray direct contact heat exchanger (DCHX) were conducted using a 275/sup 0/ geothermal fluid as an energy source and different hydrocarbons as working fluids. The baseline performance tests with the direct contact unit were conducted with isobutane. The thermal performance of the unit met or exceeded the design goals for individual tray thermal efficiencies and pinch points. Hydraulically the column operated near recommended design fluid velocities. Following the completion of these tests, the DCHX was operated with different mixtures of hydrocarbon working fluids. Different combinations of the isobutane/hexane family were tested followed by a series with propane/isopentane fluids. The testing conducted with the direct contact unit showed that the sieve tray column is a very efficient heat exchange device although some degradation in boiling tray efficiency and column throughput were noted when mixtures were used.
Date: January 1, 1983
Creator: Mines, G.L. & Wiggins, D.J.
Partner: UNT Libraries Government Documents Department

Synthesis of metastable aluminum-based intermetallics by mechanical alloying

Description: We have used mechanical alloying (MA) to prepare fine-grained powders of Al 25 at. % X (X = Ti, Zr, Hf) having the metastable cubic L1{sub 2} structure. Hexane (C{sub 6}H{sub 14}) is added to the milling media to avoid the agglomeration of the aluminum powder. Carbon from the decomposition of the hexane incorporates into the powder to form a fine dispersion of carbides. These carbides are beneficial because they limit grain growth during consolidation and add strength to the alloy. We have consolidated the mechanically alloyed powders using conventional hot-pressing and non-conventional dynamic pressing. We used hot pressing to consolidate mechanically alloyed L1{sub 2}-Al{sub 3}Ti powder in the presence of excess of Al. The compact has the DO{sub 22} structure. Its room-temperature compressive strength is 1.2 GPa (exceeding that of cast Al{sub 3}Ti by a factor of 10). At 400{degrees}C, the compressive strength decreases to 1 GPa. The ductility, which is negligible at room temperature, increases to 6% at 400{degrees}C. We used dynamic pressing to consolidate L1{sub 2}-Al{sub 5}CuZr{sub 2} powder. The compact, having the L1{sub 2} structure, has fine grains (44 nm) and a fine dispersion of ZrC precipitates (7 nm). Its hardness is in the range of 1030 kg mm{sup {minus}2}. Current efforts are to investigate ternary alloys based on fine-grained trialuminides which include a ductile second phase. 26 refs., 8 figs.
Date: January 1, 1991
Creator: Schwarz, R.B.; Srinivasan, S. & Desch, P.B.
Partner: UNT Libraries Government Documents Department

Solvent tailoring in coal liquefaction. Quarterly report, May 1982-August 1982. [Comparison of subcritical and supercritical conditions]

Description: The initial objective of this work was to study the phase distribution of donor solvents and solvent mixtures during the liquefaction of coal, to investigate the effects of phase distribution on coal conversion, and to determine the advantages, if any, of operating at subcritical and/or supercritical conditions. Computer simulations were used to predict the phase distribution, for various binary systems, as a function of temperature. The FLASH program was used to theoretically predict phase distribution for various model systems. Due to limitations in the computer program, success was achieved only in a few cases. Even in these cases, the existence of two-phase regions was observed only at temperatures and pressures far below normal liquefaction conditions. An extensive review of the literature was carried out in order to survey methods of experimentally studying vapor-liquid equilibria. Finally, some preliminary laboratory studies were carried out with the use of benzothiophene-dodecane as the model reaction system. It was felt that the study of the effect of reactor configuration on conversion would provide insight into whether phase distribution or mass transfer was the limiting consideration for coal conversion. However, no conclusive results were obtained from these studies.
Date: January 1, 1982
Creator: Tarrer, A.R.; Guin, J.A.; Curtis, C.W. & Williams, D.C.
Partner: UNT Libraries Government Documents Department

The mobile phase in coals: Its nature and modes of release: Part 2, Efforts to better define the nature and magnitude of the mobile phase: Final report

Description: Several liquefaction conditions and many extracting solvents were used in attempts to set up conditions such that, as the conditions became more severe, progressively more hexane-solubles, analyzable by GC/MS, would be released. It was hoped to identify a threshold beyond which trapped mobile phase molecules would become evident. A set of 10 hexane-soluble fractions, all obtained under various conditions from the same coal (a sample of Herrin No. 6 seam, Illinois), were subjected to analysis by tandem mass spectrometry (MS/MS). Yields ranged from 0.6 to 16% of the organic matter in the coal. Prominent constituents of all of the fractions were homologous series of alkyl aromatic hydrocarbons, phenols and heterocycles, notably alkylacenaphthenes. Alkyl chains were either unbranched or lightly branched. There was a similarity in the spectra of all of the fractions irrespective of yield. The ease with which a certain homologous series can be released from a coal is highly variable. Thus the data are consistent with the concept of a mobile phase some components of which are trapped in cavities with entrances and exits of restricted size. Release of the various physically held species and the fragments from thermal breakdown of the structure will certainly present a very complex system for kinetic modeling. 30 refs., 10 tabs.
Date: April 1, 1987
Creator: Given, P.H.
Partner: UNT Libraries Government Documents Department

Vaporization at supercritical pressures and counterflow condensing of pure and mixed-hydrocarbon working fluids for geothermal power plants

Description: The Heat Cycle Research Program has as its objective the development of the technology for effecting improved utilization of moderate temperature geothermal resources. Current testing involves supercritical vaporization and counterflow in-tube condensing in an organic Rankine cycle. Results of the experiments are given for both pure and mixed-hydrocarbon working fluids. The heater and condenser behavior predicted by the Heat Transfer Research, Inc. computer codes used for correlation of the data was in excellent agreement with experimental results. A special series of tests, conducted with propane and up to approximately 40% isopentane concentration indicated that a close approach to ''integral'' condensation was occurring in the vertically-oriented condenser.
Date: January 1, 1986
Creator: Bliem, C.J.; Demuth, O.J.; Mines, G.L. & Swank, W.D.
Partner: UNT Libraries Government Documents Department

High voltage research (breakdown strengths of gaseous and liquid insulators) and environmental effects of dielectric gases. Semiannual report, April 1, 1979-September 30, 1979. [Health and Safety Research Div. , ORNL]

Description: A number of gas mixtures are suggested for industrial-scale testing. Electron attachment rates were measured and unfolded to give attachment cross section functions for CCl/sub 3/F, CCl/sub 2/F/sub 2/, and CClF/sub 3/ each in N/sub 2/, and for CCl/sub 3/F in Ar. Electron attachment rates were measured also for n-C/sub 6/F/sub 14/ in both Ar and N/sub 2/. The effects of molecular structure on energy, cross section, and lifetime of negative ion states of organic molecules were considered. A study was made of the potential role of electron detachment in breakdown. The role of dipolar scattering of electrons in inhibiting breakdown was investigated. The nature of synergisms among constituents of a gas dielectric mixture is discussed. Examples are cited from recent breakdown measurements. Breakdown measurements in plane-plane geometry were made for CF/sub 4/, 1,1,1-CH/sub 3/CF/sub 3/, and CHF/sub 3/. Similar measurements were conducted with binary mixtures containing one of (c-C/sub 4/F/sub 8/, SF/sub 6/) and one of (CF/sub 4/, CH/sub 2/F/sub 2/, 1,1,1-CH/sub 3/CF/sub 3/, CH/sub 2/F/sub 2/). Of special interest in these results were observed synergisms and the effect of dipole moment on the breakdown strengths. The initial fragmentation of 1,1,2-C/sub 2/Cl/sub 3/F/sub 3/ under electron impact was studied. Final decomposition products of sparked SF/sub 6//2-C/sub 4/F/sub 6/ mixtures were identified and quantified. The breakdown products of SF/sub 6/ were studied. Impulse measurements concentrated on c-C/sub 4/F/sub 8//SF/sub 6/ mixtures. Values of V/sub 50/, V/sub NO/, and V/sub 10x/ were obtained and evaluated. In the practical conditions of cylindrical geometry with and without surface roughness, many multicomponent mixtures of the gases SF/sub 6/, c-C/sub 4/F/sub 8/, 2-C/sub 4/F/sub 8/, N/sub 2/, and 1,1,1-CH/sub 3/CF/sub 3/ were tested, at both 1 and 4.4 atmospheres. The electric fields were calculated. In the study of liquid dielectrics n-hexane and perfluoro-n-hexane were tested. ...
Date: January 1, 1980
Creator: Christophorou, L.G.; James, D.R.; Pai, R.Y.; Mathis, R.A.; Sauers, I.; Frees, L. et al.
Partner: UNT Libraries Government Documents Department

Effect of taggant vapor adsorption and containment on the pedetonation detection of explosives

Description: Predetonation detection of explosives in realistic scenarios may be accomplished by detecting vapors emitted by the explosive. These vapors could be either the vapor emitted from the inherent compounds present in the explosive or the vapor emitted by a specific vapor taggant introduced into the explosive at the time of manufacture. The emitted vapor concentration in various detection scenarios can be diminished either by vapor adsorption onto adsorptive surfaces present in the scenario, e.g., clothing, curtains, rugs etc., or by enclosing the explosive in a relatively airtight enclosure, e.g., box, luggage, etc., which will impede the vapor emission into the detection scenario. These two effects are modeled to ascertain the magnitude of the vapor concentration reduction in various scenarios. Experiments have been performed to provide a necessary input parameter for the containment model and to confirm the predictions of the model. Seven potential vapor taggants were experimentally examined for their vapor concentration depletion by adsorption in a typical scenario. The potential vapor taggants are perfluorodimethylcyclobutane (PDCB), perfluoromethylcyclohexane (PMCH), perfluorodimethylcyclohexane (PDCH), perfluorodecalin (PFD), L-4412 (a 3M Company proprietary compound), decafluorobiphenyl (DFBP), octafluoronaphtalene (OFN), and octafluorotoluene (OFT). Six enclosures were examined experimentally for their ability to contain taggant vapors. Of these, a box filled with styrofoam packing, a suitcase, a heat sealed polyethylene bag, and an attache case provided no significant impediment to the release of the vapor taggant into the detection scenario, i.e., these enclosures had a negligible degree of airtightness. The remaining two examined enclosures, a paint can and a zip lock plastic bag, showed significant vapor containment and thus possibly could hinder the vapor detection of explosives which are placed in these enclosures.
Date: October 1, 1979
Creator: Senum, G I; Ferreri, E M; Greene, M W; Gergley, R P & Dietz, R N
Partner: UNT Libraries Government Documents Department

Analyses of mixed hydrocarbon binary thermodynamic cycles for moderate temperature geothermal resources

Description: A number of binary geothermal cycles utilizing mixed hydrocarbon working fluids were analyzed with the overall objective of finding a working fluid which can produce low-cost electrical energy using a moderately low temperature geothermal resource. Both boiling and supercritical shell-and-tube cycles were considered. The performance of a dual-boiling isobutane cycle supplied by a 280/sup 0/F hydrothermal resource (corresponding to the 5MW pilot plant at the Raft River site in Idaho) was selected as a reference. To investigate the effect of resource temperature on the choice of working fluid, several analyses were conducted for a 360/sup 0/F hydrothermal resource, which is representative of the Heber resource in California. The hydrocarbon working fluids analyzed included methane, ethane, propane, isobutane, isopentane, hexane, heptane, and mixtures of those pure hydrocarbons. For comparison, two fluorocarbon refrigerants were also analyzed. Preliminary estimates of relative heat exchanger size (product of overall heat transfer coefficient times heater surface area) were made for a number of the better performing cycles. For the 280/sup 0/F resource, a mixture of 90% propane and 10% isopentane in a supercritical cycle showed the highest value of net geofluid effectiveness of the working fluids assessed. The more promising of the cycles employing mixed hydrocarbon working fluids require heaters which are estimated to range from seven to approximately 50% larger in total surface area than those for the reference cycles.
Date: January 1, 1981
Creator: Demuth, O.J.
Partner: UNT Libraries Government Documents Department

Survey of LWR environmental control technology performance and cost

Description: This study attempts to establish a ranking for species that are routinely released to the environment for a projected nuclear power growth scenario. Unlike comparisons made to existing standards, which are subject to frequent revision, the ranking of releases can be used to form a more logical basis for identifying the areas where further development of control technology could be required. This report describes projections of releases for several fuel cycle scenarios, identifies areas where alternative control technologies may be implemented, and discusses the available alternative control technologies. The release factors were used in a computer code system called ENFORM, which calculates the annual release of any species from any part of the LWR nuclear fuel cycle given a projection of installed nuclear generation capacity. This survey of fuel cycle releases was performed for three reprocessing scenarios (stowaway, reprocessing without recycle of Pu and reprocessing with full recycle of U and Pu) for a 100-year period beginning in 1977. The radioactivity releases were ranked on the basis of a relative ranking factor. The relative ranking factor is based on the 100-year summation of the 50-year population dose commitment from an annual release of radioactive effluents. The nonradioactive releases were ranked on the basis of dilution factor. The twenty highest ranking radioactive releases were identified and each of these was analyzed in terms of the basis for calculating the release and a description of the currently employed control method. Alternative control technology is then discussed, along with the available capital and operating cost figures for alternative control methods.
Date: March 1, 1980
Creator: Heeb, C.M.; Aaberg, R.L.; Cole, B.M.; Engel, R.L.; Kennedy, W.E. Jr. & Lewallen, M.A.
Partner: UNT Libraries Government Documents Department

Analysis of organic compounds in water by direct adsorption and thermal desorption. [Dissertation]

Description: An instrument was designed and constructed that makes it possible to thermally desorb organic compounds from wet adsorption traps to a gas chromatograph in an efficient and reproducible manner. Based on this device, a method of analyzing organics in water was developed that is rapid, sensitive, and of broader scope than previously published methods. The system was applied to the analysis of compounds with a wide range of volatilities. Temperature and flow parameters were investigated and specific procedures for quantitation were established. Real samples, including tap water and well water, were also analyzed with this system. Depending on the analysis requirements, the thermal desorption instrument can be used with either packed column or high resolution open-tubular column gas chromatography. The construction plans of normal and high-resolution systems are presented along with chromatograms and data produced by each. Finally, an improved thermal desorption instrument is described. Modifications to the basic system, including splitless injection onto a capillary column, automation, dual cryogenic trapping, reduction of scale, and effluent splitting to dual detection are discussed at length as they relate to the improved instrument.
Date: March 1, 1980
Creator: Ryan, J.P. Jr.
Partner: UNT Libraries Government Documents Department

Inhalation developmental toxicology studies: Teratology study of n-hexane in rats: Final report

Description: The straight chain hydrocarbon, n-hexane, is a volatile, ubiquitous solvent used in industrial, academic, and smaller commercial environments. The significant opportunity for women of child-bearing age to be exposed to this chemical prompted the undertaking of a study to assess the developmental toxicity of n-hexane in an animal model. Timed-pregnant (30 animals per group) and virgin (10 animals per group) Sprague-Dawley rats were exposed to 0 (filtered air), 200, 1000, and 5000 ppM n-hexane (99.9% purity) vapor in inhalation chambers for 20 h/day for a period of 14 consecutive days. Sperm-positive females were exposed for 6 to 19 days of gestation (dg) and virgins were exposed concurrently for 14 consecutive days. The day of sperm detection was designated as 0 dg for mated females. Adult female body weights were monitored prior to, throughout the exposure period, and at sacrifice. Uterine, placental, and fetal body weights were obtained for gravid females at sacrifice. Implants were enumerated and their status recorded as live fetus, early or late resorption, or dead. Live fetuses were sexed and examined for gross, visceral, skeletal, and soft-tissue craniofacial defects. 16 refs., 3 figs., 7 tabs.
Date: December 1, 1987
Creator: Mast, T.J.
Partner: UNT Libraries Government Documents Department

Liquid fuels production from biomass. Progress report No. 5, July 1-September 30, 1978

Description: The current program to convert biomass into liquid hydrocarbon fuels is an extension of the previous program to ferment marine algae to acetic acid. In that study, it was found that marine algae could be converted to higher aliphatic organic acids and that these acids could be readily removed from the fermentation both by membrane or liquid-liquid extraction. It was then proposed to convert these higher organic acids to aliphatic hydrocarbons via Kolbe Electrolysis, which may be used as a diesel fuel. The specific goals for the current program are: (1) Establish conditions under which substrates other than marine algae may be converted in good yield to organic acids. The primary task in this regard is methane suppression. (2) Modify the current 300 liter fixed packed bed batch fermenter to operate in a continuous mode. (3) Change from membrane extraction of organic acids to liquid-liquid extraction. (4) Optimize the energy balance of the electrolytic oxidation process. The primary task in this regard is to reduce the working potential required for the electrolysis while maintaining an adequate current density. (5) Scale the entire process up to match the output of the 300 liter fermenter. The accomplishments in this program are on schedule. Substantial progress has been made on the problem of methane suppression through the use of sulfide addition and the identification of bromoethane-sulfonic acid as a specific inhibitor of methanogenesis. A conceptual design of a continuously fed fixed packed bed fermenter is presented. Experimental results show that the electrolysis of organic acids produced by fermentation to liquid hydrocarbon fuels already have a favorable energy balance of 6/1 based on the applied potential and over 10/1 based on the working potential.
Date: January 1, 1978
Creator: Sanderson, J.E. & Wise, D.L.
Partner: UNT Libraries Government Documents Department

Power-cycle studies for a geothermal electric plant for MX operating bases

Description: Binary geothermal plants were investigated for providing electrical power for MX missile bases. A number of pure hydrocarbons and hydrocarbon mixtures were evaluated as working fluids for geothermal resource temperatures of 365, 400, and 450/sup 0/F. Cycle thermodynamic analyses were conducted for pure geothermal plants and for two types of coal-geothermal hybrid plants. Cycle performance results were presented as net geofluid effectiveness (net plant output in watts per geofluid flow in 1 bm/hr) and cooling water makeup effectiveness (net plant output in watts per makeup water flow in 1 bm/hr). A working fluid containing 90% (mass) isobutane/10% hexane was selected, and plant statepoints and energy balances were determined for 20MW(e) geothermal plants at each of the three resource temperatures. Working fluid heaters and condensers were sized for these plants. It is concluded that for the advanced plants investigated, geothermal resources in the 365 to 450/sup 0/F range can provide useful energy for powering MX missile bases.
Date: November 1, 1981
Creator: Bliem, C.J. & Kochan, R.J.
Partner: UNT Libraries Government Documents Department

Solar photo-thermal catalytic reactions to produce high value chemicals

Description: This report presents a summary of the research work accomplished to date on the utilization of solar photo-thermal energy to convert low cost chemical feedstocks into high $-value chemical products. The rationale is that the solar IR-VIS-UV spectrum is unique, supplying endothermic reaction energy as well as VIS-UV for photochemical activation. Chemical market analysis and product price distribution focused attention on speciality chemicals with prices >$1.00/lb, and a synthesis sequence of n-paraffins to aromatics to partial oxidized products. The experimental work has demonstrated that enhanced reaction effects result from VIS-UV irradiation of catalytically active V2O5/SiO2. Experiments of the past year have been on dehydrogenation and dehydrocyclization of n-paraffins to olefins and aromatics with preference for the latter. Recent results using n-hexane produced 95% conversion with 56% benzene; it is speculated that aromatic yield should reach {approximately}70% by further optimization. Pilot- and commercial-scale reactor configurations have been examined; the odds-on-favorite being a shallow fluid-bed of catalyst with incident radiation from the top. Sequencing for maximum cost effectiveness would be day-time endothermic followed by night-time exothermic reactions to produce the products.
Date: April 1, 1992
Creator: Prengle, H.W. Jr. & Wentworth, W.E. (Houston Univ., TX (United States))
Partner: UNT Libraries Government Documents Department

Analyses of mixed-hydrocarbon binary thermodynamic cycles for moderate-temperature geothermal resources using regeneration techniques

Description: Studies of basic binary geothermal cycles utilizing mixtures of hydrocarbons have shown better performance than for pure fluids for a moderate temperature (360/sup 0/F) resource. However, a loss is net geofluid effectiveness (watt-hours net plant output/1bm geofluid) results when the geofluid outlet temperature is limited to temperatures in excess of 160/sup 0/F to alleviate a silica precipitation problem. This study examined three working fluids consisting of binary mixtures of hydrocarbons to see if use of regenerative preheating techniques such as turbine exhaust recupation and/or turbine bleed could recover the loss in geofluid effectiveness for a 160/sup 0/F geofluid outlet temperature. Results showed that with the most promising of the three working fluids a turbine exhaust recuperator alone is sufficient to recover all the lost effectiveness while maintaining the geofluid outlet temperature at 160/sup 0/F. A brief study to investigate cold weather operation with that working fluid, and using the recuperator, showed no major detrimental response of the system; however, silica precipitation may present a problem in extremely cold weather, as the geofluid outlet temperature dropped below 160/sup 0/F for the lowest wet bulb temperatures studied.
Date: December 1, 1981
Creator: Demuth, O.J. & Kochan, R.J.
Partner: UNT Libraries Government Documents Department

Some Physical and Chemical Properties of Scandium and the Rare Earths

Description: Conductances, densities, partial molal volumes, solubilities, and transference numbers were measured for scandium chloride, nitrate, and perchlorate. The stability constants of the chelates formed by the rare earths and scandium with ME(l,2-bis- STA2-di(carboxymethyl)aminoethoxy!ethane) and DE(2,2 -bis- STAdi(carboxymethyllaminoldiethyl ether) were measured polarographically. In addition, the stability constants of the scandium chelates of HEDTA (N -hydroxyethyl)-ethylenediamine-N,N,N -triacetic acid), EDTA- (ethylenediamine-N,N,N ,N -tetraacetic acid), DCTA (l,2-diaminocyclohexane-N,N,N ,N -tetraacetic acid), and DE TPA ((carboxymethyl)-bis- (2-di- (carboxymethyl)aminoethyllamine) were also measured. (auth)
Date: July 1, 1959
Creator: Hiller, M. A. & Powell, J. E.
Partner: UNT Libraries Government Documents Department