Grains crushing

Chuhan F. A., Kjeldstad A., Bjprlykke K., and Hpeg K. (2000b) Porosity loss in sand by grain crushing—experimental evidence and relevance to reservoir quality. Mar. Petrol. Geol. 19, 39-53. 

Downward Intrusion of weaker material Cataclasls (Grain crushing)... 

Fig 2. Grain crushing produced as a result of experimental compaction at 30 MPa corresponding to an overburden of 3-4 km at hydrostatic pore pressures. 

Carbonate sand may compact mechanically by grain crushing in the same manner as quartz sand. Sand from calcareous fossils (microporous carbonate) initially has a very high compressibility, but at stresses exceeding about 15-20 MPa they behave similarly to quartz sand (Fig. 7). 

Filthy conditions, due to rodent or insect population, may be observed in a grain warehouse. The inspector notes rat-chewed flour sacks and sacks contaminated with rat excrement. He removes a sample of sacking and flour from such contaminated areas and submits them to the analyst. Urine fluoresces under ultraviolet light. Where rodent urine is to be confirmed, the xanthydrol test is one of several that may be used. Excreta pellets may be moistened with water or an appropriate clearing solution and crushed for observation under the compound microscope. The presence of striated hair fragments indicates rodent excrement. 

In the preparation of many solid state reference materials, reduction of the grain size plays an important role. Usually this reduction is required because of the measurement methods to be used both in the projects and later by the users of the reference material, as well as to come to an acceptable minimum sample intake. The minimum sample intake can be defined as the minimum amount of material needed, so that the heterogeneity of the material does not affect the repeatability of the measurement method. The reduction of the grain size is usually implemented by crushing and/or grinding techniques. The techniques employed and the equipment used must be suitable for the purpose of processing the material. Potential problems of contamination, loss of volatile components, and/or other physical and... 

Mechanical attrition is used to remove most of the spent binder. First, dry attrition or abrasion processes crush lumps to grain size. Mechanical abrasion is then used to separate the binder from the sand grains. Sometimes, sand is pneumatically propelled against a metal target plate. The impact of the sand on the plate scrubs off the clay and resin coating from the sand grains. Fines are separated and removed by dry classification. 

A wide-mouth 1-1. Erlenmeyer flask is supported inside a water bath of at least 2-1. capacity so that the bottom of the flask is not in contact with the bottom of the bath. The bath is filled with water at about 15° to cover at least half the height of the flask. The flask is fitted with a moderate-speed stainless-steel propeller-type stirrer, and 350 ml. of nitric acid (sp. gr. 1.4) at 20° is poured into it. Veratraldehyde,2 70 g. (0.42 mole) (Note 2), is crushed at least as fine as rice grains and is slowly added in small portions to the acid. The rate of addition should be such that it requires about 1 hour to add all the aldehyde. It is helpful, although not usually necessary, to add two or three ice cubes to the bath at the start of the nitration. The internal temperature is chocked from time to time and should be held between 18°... 

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