Grain spherical

At the higher flow rates, the film grew as a fine-grained spherical form. At lower... 

Figure Bl.17.9. A CoSi grain boundary as visualized in a spherical-aberration-corrected TEM (Haider et a/ 1998). (a) Individual images recorded at different defocus with and without correction of C(b) CTFs in the case of the uncorrected TEM at higher defocus (c) CTF for the corrected TEM at only 14 nm underfocus. Pictures by courtesy of M Haider and Elsevier.

The ethyl acetate is distilled at 70—100°C, leaving spherical particles. This graining operation requires ca 1 to 1.5 h. Grain density and size are determined by the concentration of salt in solution, the temperature and time of the dehydration, agitation speed, and the rate of distillation of the ethyl acetate. 

In bulk-crystallized polymers, lamellae are often organized into spheruHtes, spherical stmctures which grow outward from a point of nucleation, typically to about 0.01 mm in diameter. SpheruHtes are in some ways similar to the grain stmcture in metals. They can make a polymer brittle and also reduce transparency. 

Arsenic added ia amounts of 0.1—3% improves the properties of lead-base babbitt alloys used for beatings (see Bearing materials). Arsenic (up to 0.75%), has been added to type metal to increase hardness and castabiUty (21). Addition of arsenic (0.1%) produces a desirable fine-grain effect in electrotype metal without appreciably affecting the hardness or ductihty. Arsenic (0.5—2%) improves the sphericity of lead ammunition. Automotive body solder of the composition 92% Pb, 5.0% Sb, and 2.5% Sn, contains 0.50% arsenic (see Solders and brazing alloys). 

The porosity of a filter mass is an important factor. This property is best defined by experiment. A general rule of thumb is that for masses with the effective size greater than 0.4 - 0.5 mm and a specific maximum diameter below 1.2 mm the porosity is generally between 40 and 55 % of the total volume of the filter mass. Layers with spherical grains are less porous than those with angular material. 

IT IS ASSUMED THAT THE PARTICLES ARE OF UNIFORM SPHERICAL SHAPE HAVING SPECIFIC GRAVITY ONE AND THAT THE DUST CONCENTRATION IS 0.6 GRAINS PER 1000 CU. FT. OF AIR, THE AVERAGE OF METROPOLITAN DISTRICTS. 

At temperatures in the range of 850 to 950 °F (454—510 °C), permanent structural changes, such as spheroidization, take place in the boiler steel. In this process, the pearlite phase component disappears as the laminar cementite gradually changes into spherical grains. 

The thermal transformation of laminar cementite in the pearlite phase of carbon steel to spherical grains. 

A first approximate approach for estimating N,pb, or /tpb.n is to use scanning electron microscopy to estimate the average grain size, d, of the electrode. One then assumes spherical grains for the electrode film and semispherical grains in contact with the solid electrolyte to obtain ... 

Most of the electrochemical promotion studies surveyed in this book have been carried out with active catalyst films deposited on solid electrolytes. These films, typically 1 to 10 pm in thickness, consist of catalyst grains (crystallites) typically 0.1 to 1 pm in diameter. Even a diameter of 0.1 pm corresponds to many (-300) atom diameters, assuming an atomic diameter of 3-10 10 m. This means that the active phase dispersion, Dc, as already discussed in Chapter 11, which expresses the fraction of the active phase atoms which are on the surface, and which for spherical particles can be approximated by ... 

---