Solid primary properties

Dichalcogenolene complexes have been characterised by means of a large number of techniques. Nonetheless, solid-state diffraction techniques play a primary role, also in view of the importance of solid-state properties of metal... 

In addition to these compilations of crystal data in which instances of polymorphism may be recorded, a number of texts on the subject of the solid state properties of organic compounds contain many examples of polymorphism. Since these books are based in part, at least, on work by the authors not published elsewhere, they may be considered as primary literature sources. Particularly noteworthy in this regard are the books by Pfeiffer (1922), Kofler and Kofler (1954), and McCrone (1957). 

Factors that Affect Flaw Properties An overview of the primary factors that affect the bulk solid flow properties. 

These are solid structures in various forms with the primary property of selectivity... 

The electronic level of properties of solids is of primary importance. This is no mere chance that an important subfield of condensed matter physics and chemistry is focused on the electrons in solids. Basic sciences are fundamentally concerned with understanding and exploiting the properties of interacting electrons and atomic nuclei. With this comes the recognition that, at least in principal, almost all problems of materials can be and should be addressed within quantum theory. An understanding of the behavior of electrons in soUds is essential for explanation and prediction of solid state properties. 

As already stated, a powder is a complex form of solid material and it is made up of a very large number of individuals, each different from its neighbor. Individual, or inherent, properties have been already discussed in the previous section under the common term of primary properties. However, every time a particular powder sample is poured into a receptacle, the individual particles are located in different places from before and the structure of the powder is different. It is clear that it is not possible to predict quantitatively how a powder will behave from a knowledge of the measured properties of individual particles, and so direct measurement of bulk properties is, therefore, necessary. Because each repeated measurement on a sample will be upon a rearrangement of its population, there will be an inevitable scatter of readings. This difficulty has the consequence that the powder should be handled in as identical a manner as reasonably possible each time a measurement procedure is performed. Moreover, it would seem logical that there would be a development of standardized testing and characterization methods, but this has not happened. 

Particle characterization, i.e. the description of the primary properties of particles in a particulate system, underlies all work in particle technology. Primary particle properties such as the particle size distribution, particle shape, density, surface properties and others, together with the primary properties of the liquid (viscosity and density) and also with the concentration and the state of dispersion, govern the other, secondary properties such as the settling velocities of the particles, the permeability of a bed or the specific resistance of a filter cake. Knowledge of these properties is vital in the design and operation of equipment for solid-liquid separation. 

In discussions of the surface properties of solids having a large specific surface, it is convenient to distinguish between the external and the internal surface. The walls of pores such as those denoted by heavy lines in Fig. 1.8 and 1.11 clearly comprise an internal surface and equally obviously the surface indicated by lightly drawn lines is external in nature. In many cases, however, the distinction is not so clear, for the surfaces of the primary particles themselves suffer from imperfections in the forms of cracks and fissures those that penetrate deeply into the interior will contribute to the internal surface, whereas the superficial cracks and indentations will make up part of the external surface. The line of demarcation between the two kinds of surface necessarily has to be drawn in an arbitrary way, but the external surface may perhaps be taken to include all the prominences and all of those cracks which are wider than they are deep.,The internal surface will... 

In sintering, the green compact is placed on a wide-mesh belt and slowly moves through a controlled atmosphere furnace (Fig. 3). The parts are heated to below the melting point of the base metal, held at the sintering temperature, and cooled. Basically a solid-state process, sintering transforms mechanical bonds, ie, contact points, between the powder particles in the compact into metallurgical bonds which provide the primary functional properties of the part. 

Fillers may be broadly defined as solid particulates or fibrous materials, substantially inert chemically, incorporated in polymer compositions to modify the properties and/or to reduce cost. Cost reduction is not the primary reason to incorporate fillers in adhesives but they are used to impart specific properties such as flow, improved adhesion, mechanical, thermal, electrical and optical properties, chemical and weather resistance, and rheological behaviour. 

An important consideration is the effect of filler and its degree of interaction with the polymer matrix. Under strain, a weak bond at the binder-filler interface often leads to dewetting of the binder from the solid particles to formation of voids and deterioration of mechanical properties. The primary objective is, therefore, to enhance the particle-matrix interaction or increase debond fracture energy. A most desirable property is a narrow gap between the maximum (e ) and ultimate elongation ch) on the stress-strain curve. The ratio, e , eh, may be considered as the interface efficiency, a ratio of unity implying perfect efficiency at the interfacial Junction. 

Table III presents integral excess entropies of formation for some solid and liquid solutions obtained by means of equilibrium techniques. Except for the alloys marked by a letter b, the excess entropy can be taken as a measure of the effect of the change of the vibrational spectrum in the formation of the solution. The entropy change associated with the electrons, although a real effect as shown by Rayne s54 measurements of the electronic specific heat of a-brasses, is too small to be of importance in these numbers. Attention is directed to the very appreciable magnitude of the vibrational entropy contribution in many of these alloys, and to the fact that whether the alloy is solid or liquid is not of primary importance. It is difficult to relate even the sign of the excess entropy to the properties of the individual constituents.

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