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Influence of six types of curing on fly-ash concretes

This study presents the results of a series of concrete test pieces of three different mixtures: I/45A cement; Portland cement with additions; Portland with fly ash. All were subjected to six different types of curing, with the aim of studying the evolution of their compressive strengths in terms of the grade of "matu…

Influencia de un aditivo no comercial sobre la calidad de los yesos en construcción

At the present paper, it shows how has been studied the influence over the quality of a special sort of gypsum, when it has been added as "additive" 0,96% of potasium chlorurus (Kcl), it has been observed the variation on the mechanical proprieties and also over the time of the beginning and end of the set. Also with…

Photoemission spectromicroscopy with MAXIMUM at Wisconsin

We describe the development of the scanning photoemission spectromicroscope MAXIMUM at the Wisoncsin Synchrotron Radiation Center, which uses radiation from a 30-period undulator. The article includes a discussion of the first tests after the initial commissioning.

Modern permanent magnets for applications in electro-technology

The range of materials and properties now at the disposal of design engineers is described. Current uses of permanent magnets are reviewed, with particular attention to engineering and economic aspects. The rapid broadening of magnet uses is now occurring as traditional devices are miniaturized, and new applications a…

The Atmospheric Corrosion of Iron — A Discussion of the Physico‐Chemical Fundamentals of this Omnipresent Corrosion Process Invited Review

Abstract In this review the physico‐chemical fundamentals of the atmospheric corrosion of iron are discussed, as they result from a number of electrochemical and spectroscopic techniques, which have been applied in order to analyze the corrosion mechanism of the atmospheric corrosion during wet‐dry‐wet transitions. —…

Effect of orientation distribution and crystallinity on the measurement by x-ray diffraction of the crystal lattice moduli of cellulose I and II

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEffect of orientation distribution and crystallinity on the measurement by x-ray diffraction of the crystal lattice moduli of cellulose I and IIMasaru Matsuo, Chie Sawatari, Yuki Iwai, and Fumihiko OzakiCite this: Macromolecules 1990, 23, 13, 3266–3275Publication Date (Print…

The Effect of Temperature on the Acidic Dissolution of Steel in the Presence of Inhibitors

The corrosion of mild steel in sulfuric acid containing 4 × 10−4 M of either D-galactose thiosemicarbazone, 1 -phenyl thiosemicarbazide, or 4-phenyl thiosemicarbazide, has been studied over the temperature range 25 to 60°C by using alternating current (AC) impedance spectroscopy technique and measuring the capacitance…

Soft magnetic materials

The state of art is reviewed with an emphasis on recent research results and a view to identifying areas in which further developments in materials and processing might lead to even better properties and greater application of novel technology. Basis magnetic considerations are discussed, namely, B-H loop shape, core…

Long-lived nonmetallic silver clusters in aqueous solution: preparation and photolysis

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLong-lived nonmetallic silver clusters in aqueous solution: preparation and photolysisT. Linnert, P. Mulvaney, Arnim Henglein, and H. WellerCite this: J. Am. Chem. Soc. 1990, 112, 12, 4657–4664Publication Date (Print):June 1, 1990Publication History Published online1 May 200…

Cell dynamical system approach to block copolymers

A cell-dynamical-system (CDS) model of the microphase separation of block copolymers is described in detail. The model suggests a partial-differential-equation (PDE) model that allows us to find a close relation between the block copolymer and spinodal decomposition problems. A detailed numerical study of the CDS mode…

Electrochemical Bonding of Amines to Carbon Fiber Surfaces Toward Improved Carbon‐Epoxy Composites

Electrochemical oxidation of ω‐diamines on carbon fibers allows the bonding of these molecules to the carbon fibers. The conditions leading to this surface modification are described, and the influence of the different parameters is discussed. The structure of the bonded layer is studied by voltammetry, XPS, and SIMS.…

Crystals in Gels and Liesegang Rings

Providing the first comprehensive overview of the method of crystal growth in gels, Professor Henisch reviews the field, covering the underlying physics as well as the empirical experience of growth techniques accumulated over the past century. In addition, the book discusses the phenomenon of periodic precipitation,…

Allophane in New Zealand - a review

Studies of allophanes from New Zealand are reviewed, and a definition of the allophane group of minerals is suggested. Three types of allophane are identified, and their structures are discussed under headings Al-rich soil allophanes, Si-rich soil allophanes and stream deposit allophanes. Examples from New Zealand soi…

dc Electrical Degradation of Perovskite‐Type Titanates: II, Single Crystals

The resistance degradation of Al‐doped, Ni‐doped, and Fedoped SrTiO 3 single crystals is studied as a function of the temperature and the applied dc voltage. The individual influence of the acceptor dopants is discussed. Data of the mobility of oxygen vacancies are obtained from the determination of the time evolution…

Crystal structure determinations of synthetic sodium, magnesium, and potassium birnessite using TEM and the Rietveld method

Determination de la structure cristalline des sous-mailles des phases synthetiques analogues a la birnessite riches en Na, Mg et K. Cristallisation dans C2/m avec pour Na: a=5,175, b=2,850, c=7,337 A, β=103,18°; pour Mg: a=5,049, b=2,845, c=7,051 A, β=96,65°; pour K: a=5,149, b=2,843, c=7,176 A, β=100,76°. La structur…

dc Electrical Degradation of Perovskite‐Type Titanates: III, A Model of the Mechanism

A quantitative model for the dc voltage‐induced resistance degradation is based on the defect structural material constants and a numerical solution of the general transport problem for the mixed‐conducting perovskite‐type titanates. During degradation, a demixing of the initially homogeneous oxygen vacancy concentrat…

dc Electrical Degradation of Perovskite‐Type Titanates: I, Ceramics

The rate of the resistance degradation of doped SrTiO 3 ceramics is investigated as a function of various external and material parameters. The effects of the mutually interrelated parameters dc voltage, dc electric field, and thickness of the dielectric are described by power laws. Electron microscopic potential cont…

Shear flow near solids: Epitaxial order and flow boundary conditions

We report on molecular-dynamics simulations of Lennard-Jones liquids sheared between two solid walls. The velocity fields, flow boundary conditions, and fluid structure were studied for a variety of wall and fluid properties. A broad spectrum of boundary conditions was observed including slip, no-slip, and locking. We…

Semiconductor crystallites: a class of large molecules

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSemiconductor crystallites: a class of large moleculesMichael L. Steigerwald and Louis E. BrusCite this: Acc. Chem. Res. 1990, 23, 6, 183–188Publication Date (Print):June 1, 1990Publication History Published online1 May 2002Published inissue 1 June 1990https://pubs.acs.org/d…