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Proposed textural indexes to quantify the distribution of the portland cement clinker phases

Some textural parameters to quantify the distribution of the Portland cement clínker phases are proposed. These parameters are evaluated under reflected-light microscopy and allow the characterization of Clinker homogeneity. Their application to an industrial cement clinker is presented.

Editorial

Contribución al análisis y estudio de las posibilidades de variación de la cantidad de yeso, CaS04.2 H2O, como agresivo, del método acelerado de ensayo ASTM C452 [Continuación (1)] Parte I B

The reader should first refer to the summary of the first part of this work (published in Materials de Construction, no. 209) in order to have a clearer idea of the subject being dealt with herein. In this part of the work, the experimental results of the ECO parametre (Evolution of Organoleptic Characteristics of the…

Space groups rare for organic structures. I. Triclinic, monoclinic and orthorhombic crystal classes

Mirror planes and rotation axes lead to rarity of space groups for organic structures. Their inhibiting effect is mitigated by the simultaneous presence of glide planes or screw axes or both. To a first approximation the number of structures in each space group of a given crystal class is given by Nsg = Acc exp (- Bcc…

Evaluation of the efficiency of a repaired chloride-contaminated concrete

This report describes several tests that are being carried out on a viaduct near Madrid City, whose reinforcements have been seriously damaged by corrosion. These tests consist in measuring corrosion potentials and in a time soon to come, they will include the measurement of corrosion rates by means of the apparent Po…

The enzymatic activity of proteinase K is controlled by calcium

The fungal proteinase K (EC 3.4.21.14) is a very potent unusually stable member of the subtilisin family. Its X-ray structure determined at 0.15-nm resolution shows two bound Ca2+ ions. Ca1 is in near-ideal pentagonal bipyramidal configuration with Asp200 carboxylate and Pro175 peptide C = O in an apical, and Val177 p…

Intrinsic bending force in anisotropic membranes made of chiral molecules

A linear term linked to molecular chirality occurs in the bending energy of membranes with ${C}_{2}$ or ${D}_{2}$ symmetry. We find it to alternate in sign, depending on the direction of a cylindrical curvature, and discuss consequences for anisotropic solid membranes, tilted fluid bilayers, and ferroelectric smectic…

Die wichtigsten polymerphysikalischen Aspekte des Polycarbonats

Abstract Die sich ausweitenden Einsatzbereiche des Polycarbonats Polycarbonat auf Basis von Bisphenol A (im Text als BPA‐PC oder einfach als PC bezeichnet) . (PC) machen es notwendig, das Verständnis für die physikalischen Grundlagen auch in die mehr anwendungsorientierten Bereiche hineinzutragen. Der vorliegende Arti…

Electrochemistry of Conductive Polymers: II . Electrochemical Studies on Growth Properties of Polyaniline

Details of the growth properties of polyaniline (PA) have been studied employing electrochemical techniques (potential cycling method) and the results are reported. The electrochemical growth may be characterized as autocatalytic, and the growth rate is first order in aniline concentration. The growth rate is also dep…

Preparation of Pb(Zr,Ti)O3 thin films by sol gel processing: Electrical, optical, and electro-optic properties

Crack-free transparent ferroelectric polycrystalline Pb(Zr,Ti)O3 thin films were prepared by spin-coating solutions of complex alkoxides. The preparation of stock solution, firing, and annealing of films was described. The coating of the intermediate layer of Al2O3 increased the adhesion between Pb(Zr,Ti)O3 thin films…

Reversible change in alignment mode of nematic liquid crystals regulated photochemically by command surfaces modified with an azobenzene monolayer

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTReversible change in alignment mode of nematic liquid crystals regulated photochemically by command surfaces modified with an azobenzene monolayerKunihiro Ichimura, Yasuzo Suzuki, Takahiro Seki, Akira Hosoki, and Koso AokiCite this: Langmuir 1988, 4, 5, 1214–1216Publication…

The random free-energy barrier model for ac conduction in disordered solids

A brief review of the history of ac ionic and electronic conduction in disordered solids is given, followed by a detailed discussion of the simplest possible realistic model: the random free-energy barrier model. This model assumes conduction takes place by hopping, where the hopping charge carriers are subject to spa…

Liposome formulations with prolonged circulation time in blood and enhanced uptake by tumors.

The rapid clearance of circulating liposomes from the bloodstream, coupled with their high uptake by liver and spleen, has thus far been an obstacle to any attempts at targeting to tumors. We have assessed the impact of liposome composition on their clearance from the circulation in normal and tumor-bearing mice and o…

Solitons in quasi-one-dimensional magnetic materials and their study by neutron scattering

A review is made of theoretical concepts from nonlinear dynamics of quasi-one-dimensional magnetic materials and of experimental investigations of solitons by inelastic neutron scattering and of studies of anomalies of thermodynamic quantities such as the specific heat, magnetization, susceptibility, etc. The main inv…

On the structural evidence for a direct proton tunnelling effect in the KH2PO4-type transition

High-resolution neutron diffraction results for KH 2 PO 4 (KDP) and its deuterated form (DKDP) have been used to re-examine evidence that the large increase in the phase transition temperature, T c , on deuteration can be explained simply by the increase in the phase transition temperature, T c , on deuteration can be…

⅔ -Power Law for Copolymer Lamellar Thickness Implies a ⅓ -Power Law for Spinodal Decomposition

We demonstrate the relation $\ensuremath{\theta}=2\ensuremath{\varphi}$. Here the exponent $\ensuremath{\theta}$ is defined as $D\ensuremath{\sim}{N}^{\ensuremath{\theta}}$, where $D$ is the equilibrium lamellar thickness of the diblock copolymer ordered phase and $N$ is the molecular weight. The exponent $\ensuremath…

One-Dimensional Quasicrystal in Rapidly Solidified Alloys

A 1D quasicrystal derived from the 2D decagonal quasicrystal has been found in rapidly solidified ${\mathrm{Al}}_{80}$${\mathrm{Ni}}_{14}$${\mathrm{Si}}_{6}$, ${\mathrm{Al}}_{65}$${\mathrm{Cu}}_{20}$${\mathrm{Mn}}_{15}$, and ${\mathrm{Al}}_{65}$${\mathrm{Cu}}_{20}$${\mathrm{Co}}_{15}$ alloys. They inherit periodicity…

Symmetry and Analyticity of Energy Bands in Solids

We show that pairs of simple energy bands exist that have identical symmetries for their Bloch functions, but different symmetries for the corresponding Wannier functions. For finite crystals such pairs of bands belong to equivalent band representations. In the case of infinite crystals, we use the analyticity of simp…

Multiphonon Tunneling Conduction of LocalizedπElectrons in Amorphous Carbon Films

The temperature dependence of the dc conductivity has been measured on sputtered amorphous carbon films. The conductivity is proportional to ${T}^{n}$ with $n=15\ensuremath{-}17$ over a wide temperature range, suggesting for the first time that the multiphonon tunneling transition with weak electron-lattice coupling o…