Materials Literature
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Se presentan algunas novedades sobre la construcción de hornos con guía longitudinal forzada, y sobre el empleo de un nuevo tipo de cojinetes» Se comparan las ventajas y defectos de los tubos soldados y roblonados.
Características de la preparación del hormigón sin finos (materiales empleados^ método de elaboración, etc.) y propiedades generales (resistencias mecánicas, resistencia a la penetración del agua, retracción, etc.).
Se describe un sencillo ensayo para determinar la consistencia del hormigón fresco, en función de la penetración de una bola do 15y24 cm de diámetro y 13,608 kg de peso. Se establece vina comparación con el ensayo de asiento.
El secado de los productos de arcilla, en condiciones óptimas, exige la regulación de la velocidad de difusión del agua en el interior del ladrillo y de la velocidad de evaporación. Para lograr tal regulación en los secaderos tonel es preciso introducir ciertas modificaciones en el encañado corriente.
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A mathematical analysis is made of the redistribution of solute which occurs during the solidification, without convection, of a single-phase alloy. Calculations of solute distributions are carried out for steady state conditions, and for the transient changes in solute concentration, both in the solid and in the liqu…
hyde, but the most serious errors arise when small quantities of amino sugar are estimated in the presence
Abstract Analytical expressions for bubble radii and growth rates derived by the authors are applied in an analysis of surface boiling at high heat transfer rates. It is shown that the product of bubble radius and radial velocity is a constant, independent of the bubble radius. This circumstance permits the formulatio…
It is shown that there is a practically one-to-one correspondence between the occurrence, on the one hand, of positive (bonding) and negative (antibonding) overlap populations in LCAO theory and, on the other hand, of bonded attractions and nonbonded repulsions in VB (valence-bond) theory. This correspondence is discu…
Elongated single-magnetic-domain iron particles, 150 angstrom units in diameter, have been prepared with properties that definitely confirm the existence of a shape anisotropy effect on coercive force. This conclusion is based upon four observations: (1) Torque curve analysis shows the predominating anisotropy effect…
The coercive force predicted by theory for single-domain particles with shape anisotropy frequently far exceeds the observed value. From an examination of the results of Paine, Mendelsohn, and Luborsky on elongated iron particles, several approximate models are suggested which may exist in certain experimental situati…
Abstract Squalene was treated with benzoyl peroxide and isoprene‐dialcohol dibenzoate was isolated. It is now proved for the first time that the molecule of polyisoprene was decomposed by a free radical and the location of the scission was the CH 2 CH 2 linkage.
Abstract The relationship between the water‐vapor accessibility of cellulose and its dielectric constant at 10,000 cycles per second and 30°C. has been examined. Six different celluloses were studied. These included a cotton linters, a hydrolyzed cellulose, two regenerated celluloses, and two bleached wood pulps. In t…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLithium Absorption by Kaolin MineralsR. Greene-KellyCite this: J. Phys. Chem. 1955, 59, 11, 1151–1152Publication Date (Print):November 1, 1955Publication History Published online1 May 2002Published inissue 1 November 1955https://pubs.acs.org/doi/10.1021/j150533a009https://do…
Abstract Experiments are described in which the temperature dependence of crystallization in natural rubber, unvulcanized and vulcanized by a peroxide, was investigated dilatometrically over the temperature range −37 to 0°C. Avrami type time functions describe the progress of crystallization to a first approximation.…
Summary Changes in the flow stress of copper crystals due to changes in the temperature of deformation have been measured over a range of strains and temperatures. After correction for the effect of temperature on elastic constants the flow stress proves to be insensitive to temperature from 90°k to 180°k, falls rapid…
A colorimetric method for the estimation of elastase activity has been presented. When dyed elastin substrate prepared from horse ligamentum nuchae is used, the pH optimum lies between 8.7 and 9.4, and the reaction velocity is linear only when less than 35% of the elastin is dissolved. When compared with the gravimetr…
Magnetische Untersuchung der isothermischen α‐σ‐ und σ‐α‐Umwandlung in einer Eisen‐Chrom‐Legierung mit 48% Cr. Gleichung für den zeitlichen Verlauf der α‐σ‐Umwandlung. Paramagnetische Untersuchung der Sigmaphase.
The refractive indices of CsI were determined at three temperatures near 15, 24, and 34°C for wavelengths from 0.29 micron in the ultraviolet to 53 microns in the infrared. The thermal coefficients of index were determined for each wavelength and all data were reduced to 24°C. A dispersion equation of the Sellmeier ty…
In the preparation of barium titanate ceramics for dielectric and piezoelectric applications, careful attention must be given to many factors which determine the ultimate performance of the ceramic. In this study structural differences were observed with the aid of electron micrographs as the time and temperature of f…