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Hydration of tricalcium silicate in blended Cements manufactured with cuban tuffs

The tricalcium silicate (alite) hydration velocity in cements with and without additives is studied in the presence of "Las Carolinas" quarry tuffs from Cienfuegos province, Cuba, the alite hydration velocity is enhanced reaching velocity constants 1.5 higher than in the standard cement.

Sulfate resistance of ordinary Portland cement with fly ash

Low calcium fly ash has demonstrated to be an effective pozzolan to improve sulfate resistance of ordinary portland cement (type I). In this paper physico-chemical effects that produce this pozzolan in the mortar exposed to sulfate attack are studied. Dilution and dispersion affects are analyzed using mixes of cement…

Effect of addition of opaline siliceous rocks at different proportions to portland cement

En este trabajo se estudia la influencia de la presencia de rocas silíceas opalinas, procedentes de las provincias de Salamanca, Zamora y Avila, en las propiedades de los cementos mixtos fabricados con cemento portland y proporciones variables de estas rocas utilizadas como adiciones activas. La caracterización de est…

Structural changes accompanying hydration in nylon 6

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructural changes accompanying hydration in nylon 6N. S. Murthy, M. Stamm, J. P. Sibilia, and S. KrimmCite this: Macromolecules 1989, 22, 3, 1261–1267Publication Date (Print):March 1, 1989Publication History Published online1 May 2002Published inissue 1 March 1989https://pu…

Alkali feldspars: ordering rates, phase transformations and behaviour diagrams for igneous rocks

Abstract Homogeneous and heterogeneous phase relationships in the alkali feldspars are reviewed, and behaviour diagrams developed. Al,Si ordering is almost certainly continuous and higher order in both albite and potassium feldspar and has been established reversibly or nearly so down to below 500°C in albite and poss…

The rheology of suspensions containing polymerically stabilized particles

Abstract The non‐Newtonian viscosities of polymerically stabilized colloidal suspensions are usually predicted and correlated on the basis of data and scaling principles for Brownian hard spheres. Here, the specific effect of the stabilizer layer is investigated using suspensions of monodisperse PMMA particles with a…

An improved theory for the prediction of microcavitation thresholds

An approximate analytical formulation is presented that allows for the calculation of acoustic pressure thresholds for transient cavitation over a variety of frequencies and host fluid parameters. Specifically, R.E. Apfel's (1986) theory is extended to include an estimate of the time delay associated with the Laplace…

Electrochemical and Spectroscopic Evidence on the Participation of Quadrivalent Nickel in the Nickel Hydroxide Redox Reaction

Electrochemical and iodometric measurements on anodically charged thin film nickel hydroxide electrodes indicated an average nickel valence of . In situ visible spectroscopy of nickel hydroxide deposited on optically transparent electrodes featured one strong and broad absorption band with an intensity proportional to…

Protein‐resistant surfaces prepared by PEO‐containing block copolymer surfactants

Polyethylene oxide(PEO)-containing nonionic polymeric surfactants were studied as a possible means to produce PEO-rich surfaces by a simple coating treatment of a common hydrophobic medical material--polyethylene. Surface tension and adsorption properties of PEO/polypropylene oxide(PPO) and PEO/polybutylene oxide(PBO)…

Starburst dendrimers. 5. Molecular shape control

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStarburst dendrimers. 5. Molecular shape controlAdel M. Naylor, William A. Goddard III, Garry E. Kiefer, and Donald A. TomaliaCite this: J. Am. Chem. Soc. 1989, 111, 6, 2339–2341Publication Date (Print):March 1, 1989Publication History Published online1 May 2002Published ini…

Silsesquioxanes as models for silica surfaces

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSilsesquioxanes as models for silica surfacesFrank J. Feher, David A. Newman, and John F. WalzerCite this: J. Am. Chem. Soc. 1989, 111, 5, 1741–1748Publication Date (Print):March 1, 1989Publication History Published online1 May 2002Published inissue 1 March 1989https://pubs.…

Electromigration in metals

This paper provides an overview on the current understanding of electromigration in metals. The discussion is first focused on studies in bulk metals and alloys. This part includes a thermodynamic formulation of electromigration, a kinetic analysis of the atomic processes and a review of the theory. In addition, exper…

Explosive crystallization of amorphous substances

A phenomenon of nonlinear physics is studied in this review: the formation of characteristic, time-independent, solitary states—autosolitons (AS)—in different physical, chemical, and biological systems. The physics of As in some types of systems—systems with "positive" and "negative" thermal diffusion, uniformly gener…

Emission bands of CsCdBr3

Optical properties of CsCdBr 3 crystals have been investigated. Three emission bands peaking at 3.3, 2 and 1.8 eV are induced by ultraviolet excitation. Correlation with intrinsic luminescence properties of alkali halides leads to the assignment of the bands to emission from Br 2 2- centres.

Equilibrium hydrogen uptake and associated kinetics for the Mg-H2system at low pressures

The hydrogen concentration in Mg in equilibrium with H 2 gas, and the associated kinetics, were measured at 10 3 -10 5 times lower pressure than previously reported, by using UHV-prepared Mg samples with a thin Pd coating. Equilibrium can be established above a (pressure-dependent) critical temperature below which int…

Heat and cold denaturation of phosphoglycerate kinase (interaction of domains)

It has been shown that the denaturation of phosphoglycerate kinase (PGK) can be observed not only when the solution is heated above 30 degrees C, but also when it is cooled below this temperature. The disruption of the native PGK structure upon cooling and the subsequent formation of this structure upon heating both p…

Eigenvectors of composite systems. I. General theory

A composite system is a system formed out of different subsystems connected by interfaces. Any physical property of such a system can be described by an operator which can have a discrete matrix form or a continuous (e.g. differential) form. Some composite systems can even be formed of partly discrete and partly conti…

Effects of silane coupling agents on mica‐filled styrene‐butadiene rubber

Abstract The effects of silane coupling agents on styrene‐butadiene rubber (SBR)‐mica composites have been studied with special reference to the technical properties and polymer‐filler interaction. Silane‐treated mica improves polymer‐filler interaction, which subsequently enhances the tensile and other technically im…

Thermal conductivity of crystalline and glassy crystal cyclohexanol under pressure

The thermal conductivity λ of phases liquid, I, II, III and the glassy crystal state of cyclohexanol has been measured using the transient hot-wire method at temperatures in the range 100–370K and at pressures up to 0·7 GPa. It was inferred from the observed temperature dependence of the thermal resistivity W (= λ-1)…