Stress corrosion cracking of titanium alloys at ambient temperature in aqueous solutions
Aluminum concentration effects on stress corrosion cracking of titanium alloys at ambient temperatures in aqueous solutions of salt
Mackay, T. L.↗
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Deposition of iron corrosion products from an aqueous stream
Iron corrosion product deposition on pipe wall from aqueous stream dependent on shear rate, using radioactive tracer technique
Bartlett, J. W.↗
Inhibition of methanol cracking of Ti-6Al-4V foil - Effect of pretreatments with aqueous solutions of electrolytes
Methanol stress corrosion cracking of Ti-Al-V foil inhibited by pretreatment in aqueous solutions of electrolytes, discussing colloidal character of microcrystallites
Fugassi, P.↗
Refractive index of aqueous HCl solutions and the composition of the Venus clouds
Aqueous HCl solutions refractive index calculation from concentration dependence for Venus clouds composition
Lewis, J. S.↗
Evidence for compounds hydrolyzable to amino acids in aqueous extracts of Apollo 11 and Apollo 12 lunar fines
Compounds hydrolyzable to amino acids in aqueous extracts of Apollo 11 and 12 lunar fines, noting presence of glycine and alanine
Fox, S. W.↗
The effect of alloy composition on the mechanism of stress corrosion cracking of titanium alloys in aqueous environments
The effects of alloy composition on the aqueous stress corrosion of titanium alloys were studied with emphasis on determining the interrelations among composition, phase structure, and deformation and fracture properties of the alpha phase in alpha-beta alloys. Accomplishments summarized include the effects of alloy composition on susceptibility, and metallurgical mechanisms of stress-corrosion cracking.
Boyd, J. D.↗
Spectral reflectance of selected aqueous solutions for water quality applications
The relative specular reflectances of individual aqueous solutions having a particular chemical salt content were measured in the 2 to 20 micrometers region of the infrared component or radiant flux. Distilled water was the reflectance standard. The angle of incidence was 70.03 deg plus or minus 0.23 deg. Absolute reflectances of the solutions for the same polarization and angle of incidence were computed by use of the measured relative reflectances, one of the Fresnel equations, and the optical constants of distilled water. Phase shift and phase difference spectra were obtained by respectively applying a Kramers-Kronig dispersion analysis to the absolute and relative reflectance spectra. The optical constants of the solutions were determined by algorithms commonly associated with the Kramers-Kronig analysis. Spectral signatures that qualitatively and quantitatively characterize the solute and that show structure of the infrared bands of water were noted in the phase difference spectra. The relative and absolute reflectances, the phase shift and phase difference spectra and the optical constants are presented in graphical form. Application of these results to remote sensing of the chemical quality of natural waters is discussed briefly.
Querr, M. R.↗
The effect of alloy composition on the mechanism of stress-corrosion cracking of titanium alloys in aqueous environments
A detailed study was made of the relation between the size distribution of Ti3Al particles in a Ti-8Al alloy and the tensile properties measured in air and in saltwater. The size distribution of Ti3Al was varied by isothermal aging for various times at temperatures in the range 770 to 970 K (930 to 1290 F). The aging kinetics were found to be relatively slow. Quantitative measurements of the particle coarsening rate at 920 K (1200 F) showed good agreement with the predicted behavior for coarsening controlled by matrix diffusion, and suggested that the specific free energy of the Ti3Al alpha interface in negligible small. In all cases, the Ti3Al particles were sheared by the glide dislocations. It was concluded that there is a definite correlation between the presence of deformable Ti3Al particles and an alloy's susceptibility to aqueous stress corrosion cracking. Furthermore, the appearance of the surface slip lines and the dislocation substructure in deformed specimens suggest that the specific effect of the Ti3Al particles is to cause a nonhomogeneous planar slip character and an enhanced chemical potential of the slip bands.
Wood, R. A.↗
Optical constants of concentrated aqueous ammonium sulfate.
Using experimental data obtained from applying spectroscopy to a 39-wt-% aqueous ammonium sulfate solution, it is shown that, even though specific aerosol optical constants appear quite accurate, spectral variations may exist as functions of material composition or concentration or both. Prudent users of optical constant data must then include liberal data error estimates when performing calculations or in interpreting spectroscopic surveys of collected aerosol material.
Remsberg, E. E.↗
Growth and development in inert non-aqueous liquids
A preview is presented of the survival and growth capabilities of higher plants in non-aqueous, inert liquids. The two media which were used are mineral (white) oil and fluorochemical inert liquid FC-75. Both liquids dissolve oxygen and carbon dioxide readily, but are insoluble in water. Consequently, plants submerged in these liquids are capable of gas exchange with the atmosphere, but possess a water impermeable coating the dimensions of which are determined by the size of the liquid holding container. In a sense, growing plants in a tank of mineral oil imparts on them a cuticle. Plants plus prescribed volumes of water were innoculated into mineral oil. Organisms with minimal water supplied could then be observed. Also, submersed plants covered with an oil slick were shown to be capable of growth in dessicating atmospheres.
Siegel, S. M.↗
Internal pressures and molecular dimensions in aqueous solutions of some chlorides
On the basis of measurements of the velocity of ultrasounds in aqueous solutions of some alkaline-earth chlorides (MgCl2, CaCl2, BaCl2) the concentration and temperature dependences of the internal pressure were determined. Using these results, as well as surface tension measurements, the mean diameters of the molecular species as a function of concentration and temperature, were determined.
Auslaender, D.↗
Chemistry of the system: Al2O3(c)minus HCL aqueous
In order to study exhaust gas chemistry for the space shuttle, the vapor pressure of 2 to 1 weight mixtures of 3-M hydrochloric acid and Al2O3 was studied over a l80 minute reaction period at 31 C. The Al2O3 sample was one of high surface area furnished by NASA Langley Research Center. A brief review is given for aqueous aluminum chemistry, and the chemical reactions of combustion products (exhaust gases) of aluminum propellant binders for the space shuttle are listed.
Tyree, S. Y., Jr.↗
Compartmentalization of amino acids in surfactant aggregates - Partitioning between water and aqueous micellar sodium dodecanoate and between hexane and dodecylammonium propionate trapped water in hexane
The partitioning of amino acids (glycine, alanine, leucine, phenylalanine, histidine, aspartic acid, glutamic acid, lysine, isoleucine, threonine, serine, valine, proline, arginine) in aqueous and nonaqueous micellar systems was studied experimentally. Partitioning from neat hexane into dodecylammonium propionate trapped water in hexane was found to be dependent on both electrostatic and hydrophobic interactions, which implies that the interior of dodecylammonium propionate aggregates is negatively charged and is capable of hydrogen bonding in addition to providing a hydrophobic environment. Unitary free energies of transfer of amino acid side chains from hexane to water were determined and solubilities of amino acids in neat hexane substantiated the amino acid hydrophobicity scale. The relevance of the experiments to prebiotic chemistry was examined.
Fendler, J. H.↗
Gamma-irradiation of malic acid in aqueous solutions
The gamma-irradiation of malic acid in aqueous solutions was studied under initially oxygenated and oxygen-free conditions in an attempt to determine the possible interconversion of malic acid into other carboxylic acids, specifically those associated with Krebs cycle. The effect of dose on product formation of the system was investigated. Gas-liquid chromatography combined with mass spectrometry was used as the principal means of identification of the nonvolatile products. Thin layer chromatography and direct probe mass spectroscopy were also employed. The findings show that a variety of carboxylic acids are formed, with malonic and succinic acids in greatest abundance. These products have all been identified as being formed in the gamma-irradiation of acetic acid, suggesting a common intermediary. Since these molecules fit into a metabolic cycle, it is strongly suggestive that prebiotic pathways provided the basis for biological systems.
Negron-Mendoza, A.↗
Formation of the thioester, N,S-diacetylcysteine, from acetaldehyde and N,N'-diacetylcystine in aqueous solution with ultraviolet light
The thioester, N,S-diacetylcysteine, is formed during the illumination of phosphate buffered (pH 7.0) aqueous solutions of acetaldehyde and N,N'-diacetylcystine with ultraviolet light. The yield of N,S-diacetylcysteine relative to N-acetylcysteine and unidentified products progressively increases as ultraviolet light below 239 nm, 253 nm and 281 nm is cut off with optical filters. When ultraviolet light below 320 nm is removed with an optical filter, there is no detectable reaction. Illumination of 0.025 M N,N'-diacetylcystine with 0.5 M and 1.0 M acetaldehyde with filtered ultraviolet light gives, respectively, 20% and 80% yields of N,S-diacetylcysteine. In the reaction with 1.0 M acetaldehyde, N-acetylcysteine forms early in the reaction and later decreases with its conversion to N,S-diacetylcysteine. The prebiotic significance of these reactions is discussed.
Weber, A. L.↗
Spectroscopic evidence for aqueous alteration products on the surfaces of low-albedo asteroids
The spectral reflectances of primary components of the carbonaceous chondrite matrix materials (CCMM) and their secondary alteration products are compared with new observations of low-albedo asteroids. It is shown that the spectral differences between C-type asteroids and carbonaceous chondrites are consistent with differing degrees of aqueous alteration of CCMM.
Feierberg, M. A.↗
Aqueous alkali metal hydroxide insoluble cellulose ether membrane
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.
Hoyt, H. E.↗
Formation of the thioester, N-acetyl, S-lactoylcysteine, by reaction of N-acetylcysteine with pyruvaldehyde in aqueous solution
N-acetylcysteine reacts efficiently with pyruvaldehyde (methylglyoxal) in aqueous solution (pH 7.0) in the presence of a weak base, like imidazole or phosphate, to give the thioester, N-acetyl, S-lactoylcysteine. Reactions of 100 mM N-acetylcysteine with 14 mM, 24 mM and 41 mM pyruvaldehyde yield, respectively, 86%, 76% and 59% N-acetyl, S-lactoylcysteine based on pyruvaldehyde. The decrease in the percent yield at higher pyruvaldehyde concentrations suggests that during its formation the thioester is not only consumed by hydrolysis, but also by reaction with some substance in the pyruvaldehyde preparation. Indeed, purified N-acetyl, S-lactoylcysteine disappears much more rapidly in the presence of pyruvaldehyde than in its absence. Presumably, N-acetyl, S-lactoylcysteine synthesis occurs by rearrangement of the hemithioacetal of N-acetylcysteine and pyruvaldehyde. The significance of this pathway of thioester formation to molecular evolution is discussed.
Weber, A. L.↗