Influencia que el tipo de conglomerante ejerce en la durabilidad de los hormigones trente a los sulfatos
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Materials Literature
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Desarrollo tecnológico de la industria del cemento
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Influencia del polvo del horno de cemento sobre plantas y animales
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HEXAGONAL CELL STRUCTURES UNDER POST-BUCKLING AXIAL LOAD
Determining the approximate crushing stress of hexagonal cell structures subject to axial loading
THE CLASSIFICATION OF CROSS‐STRATIFIED UNITS. WITH NOTES ON THEIR ORIGIN
A descriptive classification of cross‐stratified units is proposed based on six objective criteria, and diagnoses are given for fifteen distinct kinds of cross‐stratified unit recognised with their aid. The origin of each kind is discussed in the light of existing observational, experimental, and theoretical studies.…
Thermal Conductivity of Silicon from 300 to 1400°K
The thermal diffusivity of pure silicon has been measured from 300 to 1400\ifmmode^\circ\else\textdegree\fi{}K. The specific heat of the same material over the same temperature range has been measured by Dennison. The thermal conductivity was obtained from the product of the thermal diffusivity, specific heat, and den…
The cyclization of natural rubber
Abstract Several methods of measuring the unsaturation remaining in natural rubber after cyclization have been compared. Approximate agreem ent was obtained with the reagents, perbenzoic acid, phenyl iododichloride and ozone; iodine chloride gave high values. Perbenzoicacid is considered the most satisfactory of these…
Carbon: A New Crystalline Phase
The electrical resistance of single crystal graphite shows a very sharp increase at above 150 kilobars, accompanied by a drifting upward with time. The behavior is typical of a first-order phase transition, and is irreversible. X-rays on the material after removal from the cell show lines of a new material with a stru…
Theory of the Electronic Polarizabilities of Ions in Crystals: Application to the Alkali Halide Crystals
A theoretical estimate of the polarizabilities of ions in the alkali halides is made by means of a procedure based upon the product approximation which distinguishes the ionic constituents in the crystals but allows for their overlap and mutual interaction. Analysis by means of the Thomas-Kuhn sum rule is used allowin…
Specific Heat of Various Graphites between 0.4 and 2.0°K
Below 1.2\ifmmode^\circ\else\textdegree\fi{}K, the specific heat of natural Madagascar graphite is: $C=13.8T+27.7{T}^{3}$ \ensuremath{\mu}J/mole deg. The coefficient of the linear term agrees well with theoretical calculations of the electronic specific heat of a pure single crystal of graphite. The ${T}^{3}$ term yie…
Magnetic First-Order Phase Transition in Single-Crystal MnAs
This paper describes an experimental and theoretical examination of a 10-\ensuremath{\mu}g $c$-axis-oriented single crystal of MnAs. The critical magnetic field for the first-order transition to the ferromagnetic phase has been measured as a function of temperature (15 to 65\ifmmode^\circ\else\textdegree\fi{}C) and pr…
Crystal Structures of KCuCl3 and NH4CuCl3
The crystal structures of the isomorphous garnet-red copper salts, KCuCl3 and NH4CuCl3, have been determined. Each compound contains discrete, planar, Cu2Cl6= dimers. These dimers are stacked above each other along the crystallographic a axis. The cation exhibits a ninefold coordination. KCuCl3 is antiferromagnetic be…
Apparatus for Tensile Testing to 5400°F in Vacuum
An apparatus for tensile testing in vacuum to 5400°F is described. A load-elongation curve is plotted during testing of a standard specimen at a selected nominal strain rate between 0.005 and 5.0 in./in./min. The load train design provides that the grips, as well as the specimen, are in the furnace hot zone. The speci…
A REVIEW OF THE REACTOR PHYSICS DATA FOR SLIGHTLY ENRICHED URANIUM, WATER- MODERATED LATTICES
The methods commonly used in making buckling, critical loading, and cell parameter measuremerts are reviewed, and the results of such measurements are summarized. Only simple uniform and multiregion lattice experiments are considered. The experimental work done at each of the laboratories involved is summarized. The m…
Purity analysis of highly purified materials by time-temperature cryometry
Visual observation of the freezing and melting of compounds in cells used for the determination of purity has uncovered some heretofore unexpected behavior. This behavior has been correlated with certain difficulties experienced in the measurement of purity, particularly when the sample is very pure. Means for partial…
Ozonation of Atactic Polypropylene
Abstract 1. It is determined by study of the accumulation of peroxides in atactic polypropylene that ozone acts as an initiator of oxidation and considerably accelerates the course of the reaction even at room temperature. 2. The surface of the oxidized specimens is an important kinetic factor in the accumulation of t…
The Polarization by Mercury of 1 to 2 keV Electrons
Calculations of the energy and angular dependence of the polarization of 1 to 2 keV electrons elastically scattered from mercury agree qualitatively with experiment, a maximum 90° polarization occurring at 1.5 keV as found experimentally.
The mechanism of ozone cracking. I. Ozone cracking of plastic films
Abstract Stretched films from partly unsaturated natural rubber hydrochloride develop cracks and fracture in ozonized oxygen. Cracking occurs only above a minimum stress level of about 70 kg./cm. 2 . Ozone sensitivity increases exponentially with stress, but goes through a maximum near the yield point of the thermopla…
The Dynamic Properties of Carbon Black Loaded Natural Rubber Vulcanizates. Part II
Abstract The dynamic shear modulus at very high strains, ( G ∞ ), of carbon black filler loaded vulcanizates is regarded as due to the product of two factors : ( a ) a hydrodynamic interaction due to filler particles, and ( b ) a second factor for which evidence is given suggesting that it arises from a few strong lin…
Heat Content of Uranium Dicarbide from 1484° to 2581°K
The heat content of uranium dicarbide was measured from 1484° to 2581°K using a drop calorimeter.