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An attempt is made to produce a model for the small strain elastic constants of polycrystalline carbons and graphites in terms of the dislocations present in the crystallites constituting the material. The model is mainly based on the effects of fast neutron irradiation on the moduli of reactor graphites and carbons,…
Deposits of ferruginous nickeliferous lateritic soils formed by weathering in place of ultramafic rocks occur at several places in northwestern California and southwestern Oregon, mostly in the Klamath Mountains province. Most of the deposits have been derived from relatively fresh peridotite, although at least one de…
Abstract Studies were conducted on the retention of Cu and Zn by H‐montmorillonite in relation to associated anion, salt concentration reaction time, pH of the equilibrium solution, and techniques. Under conditions where the pH of the equilibrium solution was too acid for formation of Cu(OH) 2 , the amounts of Cu and…
It is shown how the usual theory of phonon interaction may be extended to cover the case of one phonon having a wavelength larger than the mean free path of those with which it interacts. The results are applied to a consideration of the absorption of sound in dielectrics at arbitrary temperature.
This paper describes ``thermal dissociation'' or ``atomization,''H2⇌2 H,on a Mo or W catalyst, from 1200° to 2500°K. We emphasized transient behavior of individual species (especially H) caused by changing catalyst temperature. Reaction rates, and equilibria derived from them, confirm Langmuir's results of 50 years ag…
Abstract Das System Platin–Aluminium wurde durch thermische Analyse und rötgenographische Untersuchungen aufgeklärt. Dabei wurden folgende intermetallische Phasen gefunden: ”︁PtAl 4 „, PtAl 3 , PtAl 2 , Pt 2 Al 3 , PtAl, Pt 3 Al 2 , Pt 5 Al 3 , Pt 3 Al und Pt 13 Al 3 . Die Kristallstruktur von Pt 2 Al 3 (ähnlich Ni 2…
Measurements of the temperature dependence of the longitudinal and shear ultrasonic attenuation from 5 to 50 Mc/sec were made in SiO2, GeO2, B2O3, and As2O3 glass. In each case a relaxation loss with a distribution of relaxation times was found. The median activation energy of the relaxation process is about 500 cal/m…
The thermal decomposition of the ammonium sul‐fate, carbonate, nitrate, oxalate, and sulfate salts of praseodymium, neodymium, and samarium was investigated thermogravimetrically in the temperature range 25° to 1400° C. Each salt was decomposed at a heating rate of 2.5° C per minute. The pyrolytic sequences have been…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNovel Ring Expansion and Carbon Insertion Reactions of IsatogensWayland E. Noland and Robert F. ModlerCite this: J. Am. Chem. Soc. 1964, 86, 10, 2086–2087Publication Date (Print):May 1, 1964Publication History Published online1 May 2002Published inissue 1 May 1964https://pub…
Abstract The reaction between dicumyl peroxide and butyl rubbers has been followed by means of molecular weight measurements. In all cases except that of the rubber with highest unsaturation the molecular weight falls, and the scission efficiency of the peroxide is found to depend quite markedly upon the unsaturation.…
Blends of nylon-epoxy resins are used as adhesives. It is found by swelling tests that the epoxy resin crosslinks the nylon. By the failure of poly-N,N'-diisobutylhexamethyleneadipamide to cure and by the failure of prereactions of the nylon with phenyl glycidyl ether, it is shown that the epoxy resin reacts with the…
ADVERTISEMENT RETURN TO ISSUEArticleNEXTThe High Temperature Vaporization Properties of Boron Carbide and the Heat of Sublimation of Boron1Harry E. Robson and Paul W. GillesCite this: J. Phys. Chem. 1964, 68, 5, 983–989Publication Date (Print):May 1, 1964Publication History Published online1 May 2002Published inissue…
Abstract A procedure is described for estimating indirectly the contribution of vulcanization reactions to the build-up of network structure. This method is useful with technically important vulcanizing systems for which no direct method of estimation has been found. Errors of the theory of high elasticity are avoided…
By measurement of the specific volume of polypropylen e a s a fun ction of te mperature at various pressures, the variation of glass t emperat ure with pressure, d'Tg/dP , was d etermin ed . Within experimental error t h e m agnitude of th is qu an t ity is th e same as the valu e of Tvt1Ol /t1Cp , where t10l a nd t1…
The specifi c volumes of unvulca nizcd natural rubbcr and of a peroxide-cured vulcan izate of natural rubber were meas ured at press ures of 1-500 kg/cm2 at temperatur cs from 0 to 25 C. Observations on mercury-filled d ilatometers were made through a window in t he press urc system. No t ime effects or hysteres is ph…
Most of the known oxides of lead including the intermediate oxides Pb 12 O 19 and Pb 2 O 3 have been prepared under equilibrium conditions. Precise X‐ray powder data have been obtained for the intermediate oxide phases. Solid‐vapor equilibrium data have been obtained for reactions in the system lead‐oxygen over the ra…
The OH → OD exchange reaction between deuterium oxide vapor and cellulose has been studied for thirteen different types of cellulose; the extent of exchange in a cellulose was determined by measuring the increase in the dry weight of the sample. With each cellulose the deuteration reaction was in two stages, a rapid s…
This paper is Part IT of a two‐part series reviewing the present understanding of space charge and electrode polarization in glass and the interrelations of these concepts with the usually measured electrical properties of glass. Emphasis is placed on a theory describing the distribution of static space charge in mate…
Experimental measurements have been made on the rate of dissolution of sapphire, dense poly‐crystalline alumina, mullite, fused silica, and anorthite in a 20A1 2 O 3 ‐4OCaO‐40SiO 2 slag at 1350° to 1500° C under conditions of free and forced convection. Dissolution rates and their temperature dependence were found to…
This investigation was conducted because the development of new alloys with increased resistance to pitting corrosion appears to be largely dependent on an understanding of the effects of various concentrations of alloying elements on the initiation and steady operation of localized pitting sites on the metal surface.…