Grain composition

It was pointed out by Nieh and Wadsworth [5] that fine grain size is a necessary but insufficient condition for HSRS. This conclusion resulted from the observation that many fine-grained composites are not superplastic at high strain rates. Evidently, in addition to grain size, microstructural factors, such as detailed structure and chemical composition at the reinforcement-matrix interfaces and grain boundaries, may play important roles. 

The different grain composition of wheat, barley and oats is shown in Table 5.3. Oats are higher in fibre and fat. 

Fig. 10.5. Changes in grain composition with crushing time on the example of MDS grain, 160-125 pm, of Polish manufacture.

Large grains, low amounts of impurities and defects and solid solutions Large, needle like grains, composites with SiC, or refractory silicides Large, needle-like grains, composites with SiC, or refractory silicides... 

Daniel, C. and Triboi, E. 2000. Effects of temperature and nitrogen nutrition on the grain composition of winter wheat Effects of gliadin content and composition. J Cereal Sci 32(1) 45-56. 

General Changes in Corn Grain Composition. Samples of 18 varieties of corn, including hybrids and native varieties from distinct geographical areas of Mexico, were studied (see Figure 3 and Table IV). From Tables V and VI the most notable differences between the untreated and lime-treated corns are demonstrated an increase in mineral content and decreases in total protein, crude fiber, and ether extract. 

From infrared spectroscopy it is very difficult to obtain the composition of the amorphous silicates. This is because the spectral signature observed is a combination of grain composition, shape, size, and structure, making it difficult to isolate the pure amorphous silicate signal. This, in combination with the relatively small spectral changes caused by the composition of the silicates, makes it hard to get a definitive answer in most cases. In the case of interstellar dust we have a unique opportunity the grains are very small and (almost) all silicates are amorphous. 

Dependencies of grain composition, e.g. icy grains versus silicates or carbon, as well as their charge state, are also of interest, and for destructive collisions, the resulting fragment size distribution is important (Wurm et al. 2005). These are dependent on the microphysics of the adhesive forces between monomers (Chokshi et al. 1993 Blum Schrapler 2004). A review of laboratory simulations of dust coagulation can be found in Blum Wurm (2008). 

Figure 4. Density degree of gravel sands and basalt grain mixtures 0/30 mm grain compositions. A = 100 (d/D/1...

Grain compositions built up according to sieve line 6, n — 0.3, still have a somewhat lower void space than those built up according to sieve line 5. Because of the high filler content (26%) the quantity of sulfur which is necessary to glue the grains must be increased overpropor-tionally, as compared with the somewhat lower void space, to obtain workable mixtures (Table IV). 

Granulit and basalt were used as aggregates. The grain composition was based on sieve line 4 and 5. The respective quantities of sulfur corresponded to those which were used with unmodified sulfur concrete mixtures (16). 

Very simply, a sandstone has a grain composition of stone detritus (quartz, feldspar, detritic mica/clays) and a binder that may be clayey, quartzitic, or carbonatic (or mixtures thereof) [51, 55]. The mineral composition of limestone is mostly calcium carbonate, often derived fi om precipitated calcium carbonate and fossil shell remnants fi-om marine organisms and a calcitic binder matrix [51, 56, 57]. 

The framework grain composition and palaeo-current analyses indicate that the source rocks for the Serraria Formation were mainly granitic-gneissic rocks, schists and quartzites of the Pre-Cambrian Complex bordering the northern sector of the Afro-Brazilian depression (Garcia, 1992) (Fig. 3). Other less important source rocks include a volcanic suite. 

The Cretaceous fields are all similar in their framework grain composition and in the authigenic phases present (Table 2). There is one important difference to note, however, in comparing the two Dakota Formation producing fields. At Crooks... 

Experimental compaction shows that the loss of porosity as a function of increasing stress is a function of both grain composition and grain size (Pittman and Larese 1991, Chuhan et al. 2002) (Fig.4). The porosities observed in shallow reservoirs in the North Sea at about 2 km depth are about 30-35 % in the best sorted medium-grained sands (Giles et al. 1992, Ramm and Bjpriykke 1994) which correspond closely to those we measured during experimental compaction of similar sand in the laboratory (Chuhan et al. 2002). 

The important process variables that affect the annealing texture are grain boundary mobility and major deformation texture (or degree of cold work), preferred orientation of nuclei of the recrystallized grains, composition, initial grain size, and annealing temperature and time. 

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