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Contribución al análisis y estudio de las posibilidades de variación de la cantidad de yeso, CaS04.2 H2.O, como agresivo, del método acelerado de ensayo ASTM C452 (1) y (2) Parte II A

This part II A presents and discusses only the experimental results obtained employing 21,0 % SO3 in the selenitouse conglomerant-mixture cement P-1 (14,11 % C3A) or P-31 (7,62 % C3A) or PUZ-8 which more gypsum, respectively. These experimental results obtained thus with the parameters Δ L (%), [Δ L (%)/g cement] and…

The Effect of Delamination Defects in Carbon Fibre Skinned Honeycomb Structures

Editorial

Difraction spectrometry by laser beams

The advances in laser technology have permitted the development of numerous applications, in particular diffraction spectrometry by laser beams for the determination of the distribution curve of the particle sizes of different materials; this permits one to obtain the distribution of particle size in both wet and dry…

Tensile Strength of Uniaxial Composites

Noticias

Sulfate resistance evaluation of the cement with fly ash (using the Koch & Steinegger method)

The increase of active mineral admixtures consumption in contemporaneous cementiceous materials has stablished revision of some test methods. In the evaluation of blended cement durability, many accelerated tests of large application in portland cements become unvalid, because they don't allow to value the improvement…

Acidic macromolecules associated with the mineral phase of scleractinian coral skeletons

Abstract Macromolecules intimately associated with the mineral phase of two species of scleractinian coral skeletons are extracted in different ways and partially characterized in some detail for the first time. They are shown to contain an assemblage of glycoproteins in which the protein moiety is rich in acidic amin…

Magnetization reversal in nucleation controlled magnets. I. Theory

A statistical model, based upon earlier models of Brown [J. Appl. Phys. 33, 3022 (1962)] and McIntyre [J. Phys. D 3, 1430 (1970)] has been developed to examine the magnetization reversal of domain-wall nucleation controlled permanent magnets such as sintered Fe-Nd-B and SmCo5. Using a Poisson distribution of the defec…

Hydrodynamic transport properties of hard-sphere dispersions. I. Suspensions of freely mobile particles

The hydrodynamic transport properties of hard-sphere dispersions are calculated for volume fractions (φ) spanning the dilute limit up to the fluid–solid transition at φ=0.49. Particle distributions are generated by a Monte Carlo technique and the hydrodynamic interactions are calculated by Stokesian dynamics simulatio…

Penetration of 6061-T651 Aluminum Targets With Rigid Long Rods

We developed engineering models for forces on rigid, long rods with spherical, ogival, and conical noses that penetrated rate independent, elastic-perfectly plastic targets. The spherical and cylindrical, cavity-expansion approximations simplified the target analyses, so we obtained closed-form penetration equations.…

100 Years Liquid Crystal Chemistry

This review article presents a short description of the historical development of the chemistry of thermotropic liquid crystals and the modern molecular-statistical interpretation of the liquid crystalline state. A short survey on the present state of the liquid crystal chemistry, divided in conventional (rod-like) an…

Magnetization reversal in nucleation controlled magnets. II. Effect of grain size and size distribution on intrinsic coercivity of Fe-Nd-B magnets

Results of experiments to study the effect of grain size and grain-size distribution on the intrinsic coercivity and the hysteresis loop of sintered Fe-Nd-B magnets are presented. It is shown that the intrinsic coercivity decreases as the average grain size of the magnet is increased. It is also shown that the intrins…

Cavitation Microjets as a Contributory Mechanism for Renal Calculi Disintegration in Eswl

The rarefaction shock wave produced by an extracorporeal shockwave lithotripter can result in liquid failure at numerous discrete sites near the second focus. When the liquid fails, vapor-filled cavities can grow to relatively large sizes and subsequently collapse with enormous violence. This phenomenon, called acoust…

Thermally irreversible photochromic systems. A theoretical study

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThermally irreversible photochromic systems. A theoretical studyShinichiro Nakamura and Masahiro IrieCite this: J. Org. Chem. 1988, 53, 26, 6136–6138Publication Date (Print):December 1, 1988Publication History Published online1 May 2002Published inissue 1 December 1988https:…

Monooxygenase-like oxidation of hydrocarbons by hydrogen peroxide catalyzed by manganese porphyrins and imidazole: selection of the best catalytic system and nature of the active oxygen species

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMonooxygenase-like oxidation of hydrocarbons by hydrogen peroxide catalyzed by manganese porphyrins and imidazole: selection of the best catalytic system and nature of the active oxygen speciesP. Battioni, J. P. Renaud, J. F. Bartoli, M. Reina-Artiles, M. Fort, and Daniel. M…

Polymer Dispersed Liquid Crystals for Display Application

An overview of polymer dispersed liquid crystal (PDLC) materials, their physical properties, and potential applications in the optic and electrooptic industry is presented. These optoelectronic materials have unique properties which are expected to expand liquid crystal technology into new display and light shutter ap…

Cloning of the Alcaligenes eutrophus genes for synthesis of poly-beta-hydroxybutyric acid (PHB) and synthesis of PHB in Escherichia coli

Eight mutants of Alcaligenes eutrophus defective in the intracellular accumulation of poly-beta-hydroxybutyric acid (PHB) were isolated after transposon Tn5 mutagenesis with the suicide vector pSUP5011. EcoRI fragments which harbor Tn5-mob were isolated from pHC79 cosmid gene banks. One of them, PPT1, was used as a pr…

Toughening Behavior in Whisker‐Reinforced Ceramic Matrix Composites

The toughening behavior of whisker‐reinforced ceramics is analyzed in terms of a whisker bridging zone immediately behind the crack tip. This approach is consistent with microscopy observations which reveal that intact bridging whiskers exist behind the crack tip as a result of debonding of the whisker‐matrix interfac…