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Manganese substitutions into the portland cement clinker phases

The effect of manganese substitution into the crystal structures of the main Portland cement clinker phases (3CaO.SiO2, 2CaO.SiO2, 3CaO.Al2O3, 2CaO.Fe2O3 y 4CaO.Al2O3.Fe2O3) has been studied by X-ray and analytical electron microscopy. In oxidizing conditions, the limit of solid solution in 3CaO.SiO2 is about 0.72 ±0.…

Petrografía, propiedades físicas y durabilidad de algunas rocas utilizadas en el patrimonio monumental de Catalunya, España

The petrographical description and the values of some physical properties of three rocks used in the architectonic patrimony of Catalunya are presented. These rocks are known, in the field of the "building stones" as Girona, Folgueroles and Vinaixa stones. By ageing tests, their durability is predicted.

Uso de la ceniza volante de lignitos (c.v.l.) como materia secundaria. Un resumen considerando especialmente la situación en la República Democrática Alemana (RDA)

Not available.

Quantitative determination of tricalcicum aluminate in portland cement by X-ray diffraction

Tricalcium aluminate (C3A) is one of the constitutive phase of the cement-clinker. Its concentration influences the cement behaviour in sulphate aggressive soils. Therefore its quantification is very convenient and International standards fix its content when the concrete is used in contact with soils or liquids conta…

Structurally based predictions of ferroelectricity in seven inorganic materials with space group Pba2 and two experimental confirmations

Application of structural criteria presented previously, to all entries in the Inorganic Crystal Structure Database for materials crystallizing in space group Pba2, has led to the prediction of seven new ferroelectrics. These materials, with estimates of their respective predicted transition temperatures (To) to an as…

Corrosion of Fe-Ni alloys by Cl-containing akaganeite (beta -FeOOH); the Antarctic meteorite case

A suite of 12 iron and 8 stony meteorites from various environments and locations in Antarctica was studied, representing a range of compositions, metallographic structures, and degrees of weathering. Polished sections of meteoritic metal with adhering corrosion products were examined microscopically, with the electro…

Environmentally Assisted Cracking of Types 304L/316L/316NG Stainless Steel in 288°C Water

The objective of this study is to identity the causes of intergranular environmentally assisted cracking in non-chromium-depleted stainless steels, a phenomenon that has been observed under irradiated and unirradiated conditions. Special emphasis is placed on quantifying the possible effects of sulfur, phosphorus, and…

An x-ray photoelectron study of metal clusters in zeolites

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAn x-ray photoelectron study of metal clusters in zeolitesS. Lars T. Andersson and Russell F. HoweCite this: J. Phys. Chem. 1989, 93, 12, 4913–4920Publication Date (Print):June 1, 1989Publication History Published online1 May 2002Published inissue 1 June 1989https://pubs.acs…

Microstructural Coarsening During Sintering of Boron Carbide

The sintering behavior of boron carbide was investigated with particular attention given to microstructure development at various stages in the sintering process. Hot‐pressing and pressureless sintering techniques were employed and the effects of heating rate, firing atmosphere, and composition were used to characteri…

Thermal degradation of poly(methyl methacrylate). 2. Vinyl-terminated polymer

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThermal degradation of poly(methyl methacrylate). 2. Vinyl-terminated polymerLewis E. ManringCite this: Macromolecules 1989, 22, 6, 2673–2677Publication Date (Print):June 1, 1989Publication History Published online1 May 2002Published inissue 1 June 1989https://pubs.acs.org/d…

The role of Ca-organic interactions in soil aggregate stability .III. Mechanisms and models

Serial additions of glucose after drying-wetting cycles led to substantial aggregation of the surface soil from a red-brown earth. Addition of glucose and Ca compounds resulted in up to 80% of the soil bound in particles >2000µm with only a small portion of the soil in particles 4 0 µm. Treatment of the soils w…

Indentation Fracture Toughness of Sintered Silicon Carbide in the Palmqvist Crack Regime

The fracture toughness of a sintered dense α‐SiC was estimated by the Vickers indentation microfracture method in the low‐load Palmqvist crack regime. It was observed that the use of simultaneously obtained Vickers hardnesses does not yield reliable fracture toughness values, nor does application of the median‐crack‐d…

Water in Albitic Glasses

Infrared spectroscopy has been calibrated to provide a precise and accurate method for determining the concentrations of molecular water and hydroxyl groups in hydrous albitic glasses. At total water contents less than 4 wt.%, most of the water is dissolved as hydroxyl groups; at higher total water contents, molecular…

Porphyrin—Nucleic Acid Interactions: A Review

Research involving three important interactions of synthetic cationic porphyrins with nucleic acids: DNA binding, oxidative-reductive strand scission and photosensitized strand scission, is examined retrospectively. The observation that these porphyrins as a class can associate with DNA by intercalative binding, outsi…

Dependence of effective desorption kinetic parameters on surface coverage and adsorption temperature: CO on Pd(111)

The effective desorption kinetic parameters of CO on the Pd(111) surface have been studied by thermal desorption spectroscopy. The zero coverage effective desorption activation energy and the preexponential factor were found to be 35.5 kcal/mol and 1013.5 s−1, respectively. As a function of CO coverage, a four-stage c…

Polymer degradation and stabilization

In this paper, the effects of modified long ultra-high molecular weight polyethylene (UHMWPE) fibers on the mechanical properties of its rigid polyurethane (RPU) plastic were investigated. The UHMWPE fibers were modified by chromic acid, and the physical and chemical changes of the fiber surface were characterized by…

Piezoelectricity and pyroelectricity in polymers

Piezoelectric properties of polymeric substances arise from either the poling-induced orientation of molecular dipoles (class 1) or the uniaxial orientation of chiral chain molecules (class 2). The class 1 polymers include ferroelectric polymers, polar polymers with frozen-in dipole orientation, and the composites of…

“Janus Beads”: Realization and Behaviour at Water/Oil Interfaces

We have prepared glass spherical particles, with one hemisphere hydrophilic, and the other one hydrophobic. These objects, named "Janus beads", may be considered as amphiphilic solids . We have studied the properties of such beads at oil/water interfaces and point out that they do behave differently from ordinary soli…

Stefan and Hele-Shaw type models as asymptotic limits of the phase-field equations

Using detailed asymptotic analyses of the dynamics of the phase-field model, we show that the major sharp-interface models (Stefan, modified Stefan, Hele-Shaw, etc.) all arise as limiting cases of the phase-field equations. The scaling of the physical parameters in the microscopics leads to distinct macroscopic models…