Changes in portlandite morphology with solvent composition: Atomistic simulations and experiment

Publisher Summary This review is concerned with the neglected class of inorganic compounds, which contain ions of the same element in two different formal states of oxidation. Although the number of references cited in our review show that many individual examples of this class have been studied, yet they have very rarely been treated as a class, and there has never before, to our knowledge, been a systematic attempt to classify their properties in terms of their electronic and molecular structures. In the past, systems containing an element in two different states of oxidation have gone by various names, the terms “mixed valence,” nonintegral valence,” “mixed oxidation,” “oscillating valency,” and “controlled valency” being used interchangeably. Actually, none of these is completely accurate or all-embracing, but in our hope to avoid the introduction of yet another definition, we have somewhat arbitrarily adopted the phrase “mixed valence” for the description of these systems. The concept of resonance among various valence bond structures is one of the cornerstones of modern organic chemistry.

Mixed Valence Chemistry-A Survey and Classification

The methods and mechanisms of nonsolvent induced phase separation have been studied for more than fifty years. Today, phase inversion membranes are widely used in numerous chemical industries, biotechnology, and environmental separation processes. The body of knowledge has grown exponentially in the past fifty years, which suggests the need for a critical review of the literature. Here we present a review of nonsolvent induced phase separation membrane preparation and characterization for many commonly used membrane polymers. The key factors in membrane preparation discussed include the solvent type, polymer type and concentration, nonsolvent system type and composition, additives to the polymer solution, and film casting conditions. A brief introduction to membrane characterization is also given, which includes membrane porosity and pore size distribution characterization, membrane physical and chemical properties characterization, and thermodynamic and kinetic evaluation of the phase inversion process. ...

Preparation and Characterization of Membranes Formed by Nonsolvent Induced Phase Separation: A Review

This review examines the stages of drying, with the emphasis on the constant rate period (CRP), when the pores are full of liquid. It is during the CRP that most of the shrinkage occurs and the drying stresses rise to a maximum. We examine the forces that produce shrinkage and the mechanisms responsible for transport of liquid. By analyzing the interplay of fluid flow and shrinkage of the solid network, it is possible to calculate the pressure distribution in the liquid in the pores. The tension in the liquid is found to be greatest near the drying surface, resulting in greater compressive stresses on the network in that region. This produces differential shrinkage of the solid, which is the cause of cracking during drying. The probability of fracture is related to the size of the body, the rate of evaporation, and the strength of the network. A variety of strategies for avoiding fracture during drying are discussed.

Theory of Drying

Crystallization in pores

A new method for the simultaneous determination of the size and shape of pores: the thermoporometry

1. Ultrafiltration or hyperfiltration element, characterized in that it comprises a porous inorganic material support and a cellular, asymmetrical, microporous organic polymer membrane produced on one of the surfaces of the porous support and fitted into the pores of the porous support flush with said surface and without projecting beyond the porous support surface, said microporous membrane having a thickness less than that of the porous support.

Ultrafiltration, hyperfiltration or demineralization element, process for producing the same and its use in treating radioactive liquid wastes

Thermogravimetry and silk conditioning in lyons. A little known story (1833 – 1974)

Process for the manufacture of compact or fine-pored metallic compositions by agglomerating particulate metals

Changements d'état liquide [math] solide [math] solide d'une substance condensée dans un matériau poreux. application aux transformations allotropiques du tétrachlorure de carbone

Charles Eyraud

Papers

A new method for the simultaneous determination of the size and shape of pores: the thermoporometry

Ultrafiltration, hyperfiltration or demineralization element, process for producing the same and its use in treating radioactive liquid wastes

Thermogravimetry and silk conditioning in lyons. A little known story (1833 – 1974)

Process for the manufacture of compact or fine-pored metallic compositions by agglomerating particulate metals

Changements d'état liquide [math] solide [math] solide d'une substance condensée dans un matériau poreux. application aux transformations allotropiques du tétrachlorure de carbone