Specific gravity influence

Ethylene. Under the influence of pressure and a catalyst, ethylene yields a white, tough but flexible waxy sohd, known as Polythene. Polyethylene possesses excellent electric insulation properties and high water resistance it has a low specific gravity and a low softening point (about 110°). The chemical inertness oi Polythene has found application in the manufacture of many items of apparatus for the laboratory. It is a useful lubricant for ground glass connexions, particularly at relatively high temperatures. 

The sharpness of separation of the mineral from the gangue is dependent on (1) the stability of the suspension, which is influenced by the size of the medium (2) the specific gravity of the medium (3) the cleanliness of the medium (4) the cone angle (5) the size and ratios of the internal openings in the cyclone (inlet, apex, and vortex) and (6) the pressure at which the pulp is introduced into the cyclone. A 20° cone angle is the most common. Cyclone diameter will be determined by the separation to be made as well as by the capacity required. The 0.5- and 0.6-m (20- and 24-in) cyclones are most common in coal plants, whereas multiple cones of 0.25- or 0.3-m (10- or 12-in) diameter are used in higher-gravity separations. 

W1 is Bond work index based on 100 percent passing a 200-mesh sieve, is the sohds feed rate in kg/min, and S is weight percent solids in the feed. This represents experimental data for limestone, feldspar, sulfide ore, and quartz. The influence of Wl is believed to be due to its effect on amount of fines present in the mill. Parameters that did not affect are specific gravity of feed material, and feed size over the narrow range studied. 

To assist the engineer in making estimates, the curve in Figure 3-6 gives values of efficiency plotted against pressure ratios. The values on the curve include a 95% mechanical efficiency and a valve velocity of 3,000 feet per minute. Table 3-1 and Table 3-2 are included to permit a correction to be made to the compressor horsepower for specific gravity and low inlet pressure. They are included to help illustrate the influence of these factors to the power required. The application of these factors to... 

Figure 13.6 shows the influence of temperature on specific volume (reciprocal specific gravity). The exaet form of the eurve is somewhat dependent on the crystallinity and the rate of temperature change. A small transition is observed at about 19°C and a first order transition (melting) at about 327°C. Above this temperature the material does not exhibit true flow but is rubbery. A melt viseosity of 10 -10 poises has been measured at about 350°C. A slow rate of decomposition may be detected at the melting point and this increases with a further inerease in temperature. Processing temperatures, exeept possibly in the case of extrusion, are, however, rarely above 380°C. 

Variation in the polyamide block nature and length is a prime influence causing variations in T, specific gravity and chemical resistance. 

Because of the geometry, or morphology, of these molecules some can come closer together and more orderly than others. These are identified as crystalline and all others that behave like spagetti as amorphous. Morphology influences such properties as mechanical and thermal, swelling and solubility, specific gravity, and other properties (mechanical, physical, chemical, electric, etc.). 

This expression shows that, unlike the terminal velocity of the particle, its initial acceleration is independent of the particle size and depends only on the densities of the solid particle and the fluid. This type of acceleration, known as differential acceleration, may be exploited by designing equipment which provides frequent opportunities for accelerating the particles from rest. If a particle is allowed to accelerate from rest for a brief period of time and then arrested and subsequently allowed to fall once more, the total distance travelled by it will be influenced more by the differential acceleration and, therefore, by the specific gravities of the particle and of the liquid, than by its terminal velocity, or in other words, by its size. In this way, as the preferential movement of dense particles to the bottom of a bed... 

The density specific gravity) of coke has a strong influence on future use and can affect the characteristics of the products such as carbon and graphite. The density (specific gravity) of coke can be measured conveniently by use of a pycnometer. In the test method (ASTM D5004), the mass of the sample is determined directly and the volume is derived by determining the mass of hquid displaced when the sample is introduced into a pycnometer. Oil or other material sprayed on calcined petroleum coke to control dust will interfere. Such oil can be removed by flushing with a solvent, which must be completely removed before the density determination. 

Sharma, M. K., Isleib, D. R., Dexter, S. T. (1959). The influence of specific gravity and chemical composition on the hardness of potato tubers after cooking. Am. Potato J., 36, 105-112. 

Flame Spread The speed at which a flame will cross the surface of a material, influenced by the physical form of the fuel, air supply, the moisture content of the fuel, specific gravity, size and form, the rate and period of heating, and die characteristics/nature of the heat source. A higher flame-spread critically affects the severity of the fire in a given period of time. 

The thermal expansion coefficient governs the influence of temperature on density and therefore it is necessary to specify temperature when discussing density or specific gravity. The density of milk is of consequence since fluid milk is normally retailed by volume rather than by mass. Measurement of the density of milk using a hydrometer (lactometer) has also been used to estimate its total solids content. 

The density of bulk milk (4% fat and 8.95% solids-not-fat) at 20°C is approximately 1030 kg m 3 and its specific gravity is 1.0321. Milk fat has a density of about 902 kg m " 3 at 40°C. The density of a given milk sample is influenced by its storage history since it is somewhat dependent on the liquid to solid fat ratio and the degree of hydration of proteins. To minimize effects of thermal history on its density, milk is usually prewarmed to 40-45°C to liquify the milk fat and then cooled to the assay temperature (often 20°C). 

Equations have been developed to estimate the total solids content of milk based on % fat and specific gravity (usually estimated using a lactometer). Such equations are empirical and suffer from a number of drawbacks for further discussion see Jenness and Patton (1959). The principal problem is the fact that the coefficient of expansion of milk fat is high and it contracts slowly on cooling and therefore the density of milk fat (Chapter 3) is not constant. Variations in the composition of milk fat and in the proportions of other milk constitiuents have less influence on these equations than the physical state of the fat. 

Fig. 17. Influence of BMI/MDA molar ratio on specific gravity and water absorption (47)...

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