Grain formation

The different types of grain can be related to specific classes of stellar objects. The very hot and bright, even lavish Wolf-Rayet stars are considered to be one of the most favourable sites for grain formation, for their strong stellar winds are particularly rich in carbon. Matter thrown out by supernovas and cooling very quickly due to its expansion is also an excellent scenario for grain formation. Elements with any affinity for the solid state are likely to be abundantly transformed. 

Bematowicz, T. J., Cowsik, R., Gibbons, P. E. et al. (1996) Constraints on stellar grain formation from presolar graphite in the Murchison meteorite. Astrophysical Journal, 472, 760-782. 

Heat treatment of milk has little effect on surface tension except that sterilizing treatments cause an increase of a few dynes cm-1 coinciding with grain formation (Nelson 1949). This effect undoubtedly results from denaturation and coagulation of the proteins so that they are no longer effective surface-active agents. 

Nelson, V. 1949. The physical properties of evaporated milk with respect to surface tension, grain formation and color. J. Dairy Sci. 32, 775-785. 

The treatment of grain formation and growth is of fundamental importance within the context of our problem. In the last decade, considerable progress has been achieved in this field based on the pioneering work of the Cornell group (Salpeter et al., Draine) and the Kyoto group (Hasegasa, Yamamoto, Kozasa, Seki). 

The intention of this paper is to describe some of the more unusual safety design requirements. In order to better understand these requirements, a brief history of the type of process utilized in the manufacture of BALL POWDER is presented. Next those safety advantages internal to the process are summarized. Specific requirements in the areas of grain formation, nitroglycerine manufacture and transfer, and continuous drying are discussed. Finally, the basic fire protection system utilized is described. 

Grain formation occurs when temperatures in the expanding envelope of red giants (RGs) or in SN ejecta are low enough for the condensation of minerals. Many late-type stars are observed to be surrounded by dust shells of grains whose mineral compositions reflect the major chemistry of the gas (e.g., Little-Marenin, 1986). The study of morphological features of pristine grains, of internal... 

Henning Th. (1999) Grain formation and evolution in the interstellar medium. In Solid Interstellar Matter The ISO Revolution, Les Houches No 11 (eds. L. d Hendecourt, C. Joblin, and A. Jones). EDP Sciences, Les Ullis, pp. 247-262. 

Cross-sectional SEM studies of the samples at various deposition stages allowed the deposition mechanism to be revealed. The nickel formation inside pores is in the following way. When the electric current is passed through the porous silicon sample, the nickel grains arise inside pores at the side walls of the silicon skeleton as seen in Fig. 2. The nickel grain formation not at the pore bottoms is indicative of the partial silicon skeleton depletion [2]. The diameter of every one of the grain is up to 100 nm. 

The nickel electrodeposition into pores of mesoporous silicon begins from the metal grain formation randomly all over the surface of the silicon skeleton. The size of grains increases up to 100 nm with the deposition time and further nickel deposition is accompanied by the increase in the number of grains, which finally coalesce to threads. The moment of complete pore filling with nickel is controlled by the surface potential of the sample. 

The dependence mentioned is quantitatively similar with that of the dendritic arm size (in the case of dendritic grain formation). 

Let us consider a concrete example. If a geologist were asked what a paving stone is made up of, he might say granite, basalt, or some other rock. The substances of his world are rocks, and his basic substances are minerals. From these minerals a multitude of rocks can be formed, depending upon the types, proportions, and grain formation of the individual minerals involved. Let s take a look at a polished cross section of some typical granite (Experiment 1.1). 

The identification of polymeric grains as microreactors, in which the polymerization process is localized from the moment of grain formation and until the moment of their contact and propagation into a microheterogeneous polymeric body, has been carried out by sol-gel analysis [122] and thermometrical methods [1231 in studies of oligoesteracrylates polymerization kinetics. 

The indicated characteristic of the 3-D polymerization is a direct proof of the microheterogeneity of a process, of an active role of the liquid monomer-solid polymer interface layer and also proof of the fluctuative mechanism of polymeric grain formation and propagation. This is reflected, first of all, in the kinetic constant the numerical value of which depends on the ratio of fractal characteristics of the surface and volume of the clusters of the solid polymeric phase into the liquid monomeric phase and liquid monomer into the solid polymeric matrix. Exactly that is why the calculations of IVo according to stationary kinetic equation (4.46) cannot take into account the individual character of the postpolymerization curves. 

Order/Disorder Transition Grain Formation with No Composition Change... 

---