Materials Literature
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Relative growth rates of three freshwater plankton diatoms-Asterionella formosa, Fragilaria crotonensis, and Tabellaria flocculosa var. asterionelloides-are described from cultures suspended at various depths and during several seasons in the lake Windermere. Seasonal variation in rates recorded near the surface (i m.…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDifferential Thermal Analysis of Inorganic CompoundsSaul Gordon and Clement CampbellCite this: Anal. Chem. 1955, 27, 7, 1102–1109Publication Date (Print):July 1, 1955Publication History Published online1 May 2002Published inissue 1 July 1955https://pubs.acs.org/doi/10.1021/a…
J. K. Galt has recently suggested a mechanism for the losses observed in ferromagnetic resonance and domain wall motion in single crystals of nickel ferrite containing small amounts of divalent iron substituted for divalent nickel. Each such substitution provides one electron able to move between the various octahedra…
Abstract The orientation of the crystallites in spherulites was investigated by using special microbeam x‐ray techniques. The materials studied were: polyhexamethylene adipamide and sebacamide, polyethylene, and polyethylene terephthalate. In all these substances the c axes (molecular chains) were perpendicular to the…
A series of monodisperse polystyrene latexes has been prepared by carefully controlled emulsion polymerizations. The particle diameters of three of these latexes were determined by electron microscopy. The latex particles were dispersed on collodion membranes supported by copper grids. The microscopes had previously b…
An accurate photometric method has been developed using a Pfalz and Bauer Fluorophotometer for measuring the lysis of suspensions of M. lysodiekticus by lysozyme. This method has the distinct advantages of reproducing activities in 60 seconds after addition of the enzyme. Measurement of maximal rate of lysis in the ea…
High‐purity calcite of 10/20 mesh was calcined at various heating rates and fired to various maximum temperatures to determine the effect of these variables on the densification of the CaO produced. It was found that the heating rate during dissociation had a great bearing on densification. Shock heating conditions at…
Abstract The equilibrium curve between graphite and diamond is calculated up to 1200°K by making use of some new experimental data. The justification for extrapolating the values to higher temperatures is given. The equilibrium pressures below 1200° are shown in a table, while above 1200°K the curve can be represented…
Theoretical relationships and experimental data concerning thermal conductivity for a number of oxide materials have been compared over a wide temperature range. Deviations from the basic proportionality between k and 1/ T are caused by radiant‐energy transmission, a high Debye temperature, a low mean free path of the…
Se describen diferentes aparatos que permiten medir la consistencia de la pasta y del mortero de yeso. Se indican los resultados de algunos ensayos comparativos.
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En Clavarria, Argentina funciona un horno Lepol, por vía húmeda, con una producción diaria de 400 toneladas. El consumo de combustible es semejante al del proceso por vía seca.
La determinación de los sulfatos y de otros compuestos solubles mediante el percolador es sencilla y exacta. Por esta razón dicho método ha sido adoptado como proyecto de norma para la determinación da los componentes solubles perjudiciales.
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Se presenta un nuevo procedimiento para contrarrestar la acción nociva de las temperaturas bajas sobre los morteros y hormigones. Se Detallan su fundamento, ventajas e inconvenientes. El procedimiento es económico.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Temperature Dependence of Relaxation Mechanisms in Amorphous Polymers and Other Glass-forming LiquidsMalcolm L. Williams, Robert F. Landel, and John D. FerryCite this: J. Am. Chem. Soc. 1955, 77, 14, 3701–3707Publication Date (Print):July 1, 1955Publication History Publi…
Abstract Neutron-diffraction measurements demonstrate that the hydrogen atoms in the ferroelectric form of potassium dihydrogen phosphate are in ordered positions, in accordance with Slater’s theory and the polar orthorhombic structure. The maintenance of a crystal as a single ferroelectric domain by application of an…
thickness. The last equation is equivalent to the con- dition that the stress component cr"vanishes. Eliminat- ing all variables except ws in (5), we find d'we
The theoretical basis for exciting luminescence by the application of an electric potential to a crystalline dielectric or semiconductor is considered. Three mechanisms of excitation are each shown to be theoretically feasible in appropriate solids and with suitable local field conditions: (1) the ionization of impuri…