Stone Grinding

Reib-stein, m. grinding stone, -stelle, /. rubbed place, friction mark, reibimecht, a. not fast to rubbing. 

Abrasion under limited slip used to be, and to some extent still is, measured either with the standard Akron abrader or the Lamboum abrader. In case of the Akron abrader the sample runs under a slip angle at a constant load against the abrasive surface of an alumina grind stone. Speed and load are fixed the side force is not measured. 

Pulping Grinding stone, Chemical treatment Continuous digestion in Cooking at 340-350°F, Sulfonation at 255-350°F,... 

These negative results may be explained by inadequate preparation. The Indians grind the seeds on the metate (grinding stone) until they are reduced to flour. Then the flour is soaked in cold water, and after a short time the liquor is passed through a cloth strainer and drunk. 

Wasson has taken photographs of a young girl grinding the mushrooms (also the Ipomoea seeds or the leaves of Salvia divinorum) on a grinding stone, in a posture identical to that found on the famous Guatemalan "mushroom stones," dating back twenty-five hundred years. 

The product thus obtained consists of sharp iridescent crystals which are extremely inactive chemically. The most notable property of this material, however, is its hardness. Carborundum is almost as hard as diamond and is generally as an abrasive (i.e., in the manufacture of grinding stones and wheels, polishing papers and cloths, etc.). A lesser use lies in the incorporation of coarse Carborundum crystals into concrete or terrazzo floors to render them slipproof. 

Two views of a "mushroom stone in the Namuth collection of the pre-classic Meso-american period (1,000-500 B.C.). The figure emerging from the stipe is conjectured to be that of a young woman over a grinding stone or metate. 

The only flat machining required is slotting and milling a flat on the slider assembly. This can also be done w/a file or hand grinder or by clamping the piece in a horizontal feed unit on a drill press. The work is fed into a grinding stone mounted in the drill s chuck. 

The identification of many archaeological objects happens in the field or shortly thereafter when recovered items are cataloged. The catalog of finds includes the location and context of an item, as well as a detailed description. This description includes both identification as to type of object (for example, arrowhead, grinding stone, awl, potsherd, and so forth) and material (for example, obsidian, sandstone, bone, ceramic, respectively). Nonetheless, some objects cannot be readily identified. 

Ondruschka commented later on their observation that the reaction proceeded to high yields when the mineral reagent was mechanically cmshed to 1-3 mm pieces prior to use, but no reaction occurred when fine powder was used [43]. It appears more likely that the added minerals did not act as a catalyst but merely served as additional grinding stones during milling of the reactants. When mineral powder was used instead, the reaction mixtures became effectively diluted and the grinding less effective. 

Figure 2.51 Burrs (L) and their removal using a grinding stone (m.) and slide grinding (r.)...

Specific grinding energy (top) and area percent grinding-induced surface fracture (bottom) vs. the grain depth-of-cut to the -4/3 power for CVD silicon carbide. Tomita, Y. and Eda, H., Development of new bonding materials for fixed abrasive of grinding stone instead of free abrasives processing. Bull JSPE (in Japanese), 61, 10 (1995) 1428 Lawn, B.R. and Swain, M.V., Microfracture beneath point indentations in brittle solids, J Mater Sci, 10 (1975) 113. 

Tomita, Y. and Eda, H., Development of new bonding materials for fixed abrasive of grinding stone instead of free abrasives processing. Bull JSPE (in Japanese), 61, 10 (1995) 1428. 

Stone groundwood (SGW) is produced by the mechanical defibration of round wood logs by a grinding stone. 

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