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An engineering evaluation of thermal energy storage prototypes was performed in order to assess the development status of latent heat storage media. The testing and the evaluation of a prototype sodium hydroxide module is described. This module stored off-peak electrical energy as heat for later conversion to domestic hot water needs.
The effect of compression loads on positive nickel hydroxide electrodes is reported. Results show the electrodes could be compressed up to 20,000 kilograms without any change in capacity.
The post-test evaluation of a single heat exchanger sodium hydroxide thermal energy storage module for use in solar electric generation is reported. Chemical analyses of the storage medium used in the experimental model are presented. The experimental verification of the module performance using an alternate heat transfer fluid, Caloria HT-43, is described. Based on these results, a design analysis of a dual heat exchanger concept within the storage module is presented. A computer model and a reference design for the dual system (storage working fluid/power cycle working fluid) were completed. The dual system is estimated to have a capital cost of approximately one half that of the single heat exchanger concept.
A membrane that is insoluble in an aqueous alkali metal hydroxide medium is described. The membrane is a resin which is a water-soluble C2-C4 hydroxyalkyl cellulose ether polymer and an insolubilizing agent for controlled water sorption, a dialytic and electrodialytic membrane. It is particularly useful as a separator between electrodes or plates in an alkaline storage battery.
Hazardous waste disposal problem eliminated by regeneration. Li2CO3/ LiOH recycling process relies on low solubility of alkali carbonates in corresponding hydroxides. Li2CO3 precipitate calcined to LI2O, then rehydrated LiOH. Regeneration eliminates need to dispose caustic waste and uses less energy than simple calcination of entire waste mass.
The use of sodium hydroxide anodization (SHA) for Ti-6Al-4V adherends is examined. The SHA surface is evaluated using SEM, X-ray photoelectron spectroscopy, and Auger electron spectroscopy. The SHA procedures of Kennedy et al. (1983) were employed in this experiment. The photomicrographs of the SHA (sandblasted) and PSHA (sandblasted and pickled) oxide surface reveal that the two surfaces differ. The PSHA is patchy and similar to a chromic acid anodization surface and the porosity of the PSHA is more uniform than the SHA surface. The compositions of the surfaces are studied. It is noted that SHA is an effective pretreatment for Ti-6Al-4V adherends.
The kinetics of DMS production resulting from reaction of OH(-) with DMSP were investigated as a function of hydroxide concentration and temperature. The reaction was first-order with respect to DMSP and OH(-). The second order rate constant at 20+/-1 C is 0.0044/M/sec. The activation energy for this reaction is 14.4 kcal/mode. The investigation indicates that the rate of reaction of DMSP with OH(-) is very slow at the pH of seawater, suggesting that DMSP, which may be a major precursor of DMS in seawater, decomposes in the ocean by other mechanisms. A bacterium which produces DMS from DMSP quantitatively at rates many orders of magnitude higher than indicated by OH(-1) decomposition has been cultured, suggesting that enzymatic processes accelerate the production of DMS from DMSP in seawater.
An accelerated cycle-life test (100-percent depth of discharge) of a sintered-type Ni electrode has been carried out in a flooded cell containing different alkali metal hydroxide electrolytes such as LiOH, NaOH, KOH, RbOH, and CsOH. Decrease in Ni electrode capacity with cycling was reduced as the radius of the alkali metal ions, with possible exception of CsOH.
A range of naturally occurring divalent-trivalent metal cation hydroxides and modified artifical analogs have been synthesized and characterized. Structural and chemical properties of these minerals, determining their capability to selectively concentrate, order and alter molecules of prebiotic interest, include their anion exchange capacity and specificity, photochemical reactivity, production of nascent hydrogen, and catalytic efficiency. Properties relevant to these functions have been investigated and are discussed.
The forced-convection heat-transfer characteristics of sodium hydroxide were experimentally investigated. The heat-transfer data for heating fall slightly above the McAdams correlation line, and the heat-transfer data for cooling are fairly well represented by the McAdams correlation line.
An investigation was conducted using static capsules fabricated from "L" nickel tubing to determine the effect of temperature level, temperature gradient, and test duration on corrosion and mass transfer by molten sodium hydroxide under free-convection conditions. A base temperature range from 1000 degrees to 1600 degrees F with temperature differences to 500 degrees was studied. The rate of mass transfer was found to be strongly dependent on both temperature level and gradient. The rate shows little tendency to decrease for test durations up to 200 hours, although the concentration of nickel in the melt approaches a limited value after 100 hours.
"Thermal-gradient mass transfer" was investigated in the molten sodium hydroxide-nickel system. Possible mechanisms (physical, electrochemical, and chemical) are discussed in terms of experimental and theoretical evidence. Experimental details are included in appendixes.
Thermodynamic data for volatile hydroxides and oxyhydroxides formed from the reaction of water vapor with Cr2O3, SiO2, A12O3, Y2O3,. and ZrO2 were assembled. The volatile species formed at temperatures between 800 and 2200K in model combustion environments containing 10% water vapor and 10% oxygen at 1 and 10 bar total pressure were calculated using free energy minimization techniques. Assuming an acceptable maximum vapor pressure limit for volatile species of 10 bar, an upper use temperature for these oxides was determined at 1 and 10 bar total pressure. The dependence of these volatile species on both water vapor and oxygen pressure was determined.
The formation of volatile silicon-hydroxide species from SiO2 in water containing atmospheres has been identified as a potentially important mode of degradation of Si-based ceramics. Availability of thermodynamic data for these species is a major problem. This study is part of an ongoing effort to obtain reliable, experimentally determined thermodynamic data for these species. The transpiration method was used to measure the pressure of Si-containing vapor in equilibrium with SiO2 (cristobalite) and Ar + H2O(g) with various mole fractions of water vapor, X(sub H2O), at temperatures ranging from 1000 to 1780 K. Enthalpies and entropies for the reaction, SiO2(s) + 2H2O(g) = Si(OH)4(g), were obtained, at X(sub H2O) = 0.15 and 0.37, from the variation of lnK with 1/T according to the 'second law method'. The following data were obtained: delta(H)deg = 52.9 +/- 3.7 kJ/mole and delta(S)deg = -68.6 +/- 2.5 J/mole K at an average temperature of 1550 K, and delta(H)deg = 52.5+/-2.0 kJ/mole and delta(S)deg= -69.7 +/- 1.5 J/moleK at an average temperature of 1384 K, for X(sub H2O)= 0.15 and 0.37, respectively. These data agree with results from the literature obtained at an average temperature of 1600 K, and strongly suggest Si(OH)4(g) is the dominant vapor species. Contradictory results were obtained with the determination of the dependence of Si-containing vapor pressure on the partial pressure of water vapor at 1187 and 1722 K. These results suggested the Si-containing vapor could be a mixture of Si(OH)4 + SiO(OH)2. Further pressure dependent studies are in progress to resolve these issues.
Environmental conditions play an important role in conceptual studies of prebiotically relevant chemical reactions that could have led to functional biomolecules. The necessary source compounds are likely to have been present in dilute solution, raising the question of how to achieve selective concentration and to reach activation. With the assumption of an initial 'RNA World', the questions of production, concentration, and interaction of aldehydes and aldehyde phosphates, potential precursors of sugar phosphates, come into the foreground. As a possible concentration process for simple, uncharged aldehydes, we investigated their adduct formation with sulfite ion bound in the interlayer of positively charged expanding-sheet-structure double-layer hydroxide minerals. Minerals of this type, initially with chloride as interlayer counter anion, have previously been shown to induce concentration and subsequent aldolization of aldehyde phosphates to form tetrose, pentose, and hexose phosphates. The reversible uptake of the simple aldehydes formaldehyde, glycolaldehyde, and glyceraldehyde by adduct formation with the immobilized sulfite ions is characterized by equilibrium constants of K=1.5, 9, and 11, respectively. This translates into an observable uptake at concentrations exceeding 50 mM.
The trace contaminant control system (TCCS) located in the International Space Station s (ISS) U.S. laboratory module employs physical adsorption, thermal catalytic oxidation, and chemical adsorption to remove trace chemical contamination produced by equipment offgassing and anthropogenic sources from the cabin atmosphere. The chemical adsorption stage, consisting of a packed bed of granular lithium hydroxide (LiOH), is located after the thermal catalytic oxidation stage and is designed to remove acid gas byproducts that may be formed in the upstream oxidation stage. While in service on board the ISS, the LiOH bed exhibited a change in flow resistance that leading to flow control difficulties in the TCCS. Post flight evaluation revealed LiOH granule size attrition among other changes. An experimental program was employed to investigate mechanisms hypothesized to contribute to the change in the packed bed s flow resistance. Background on the problem is summarized, including a discussion of likely mechanisms. The experimental program is described, results are presented, and implications for the future are discussed.
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Nonpolar gases solubilities in aqueous KOH solutions in temperature range 25 to 100 C, noting activity coefficients, salting out coefficients and heats of solution