Fine materials

Filtration. Here the prime function is to retain sod or other fine materials, whde allowing water to pass through. Again, it is seen that more than one function is being performed (Fig. 6). If there were no drainage of water taking place, movement, and therefore retention of the sod, would not be of concern. 

Sintering consists of heating a mixture of fine materials to an elevated temperature without complete fusion. Surface diffusion and some incipient fusion cause the soHd particles in contact with one another to adhere and form larger aggregates. In the processing of hematite, Fe202, or magnetite,... 

The following variables can affect wall friction values of a bulk soHd. (/) Pressure as the pressure acting normal to the wall increases, the coefficient of sliding friction often decreases. (2) Moisture content as moisture increases, many bulk soHds become more frictional. (3) Particle size and shape typically, fine materials are somewhat more frictional than coarse materials. Angular particles tend to dig into a wall surface, thereby creating more friction. (4) Temperature for many materials, higher temperatures cause particles to become more frictional. (5) Time of storage at rest if allowed to remain in contact with a wall surface, many soHds experience an increase in friction between the particles and the wall surface. (6) Wall surface smoother wall surfaces are typically less frictional. Corrosion of the surface obviously can affect the abiUty of the material to sHde on it. 

Concern with regard to energy conservation has prompted the use of byproduct materials ia Portland cement concrete. Blended hydrauHc cements are produced by intimately and uniformly blending two or more types of fine materials. The primary blending materials are Portland cement, ground... 

Crystallizers with Fines Removal In Example 3, the product was from a forced-circulation crystallizer of the MSMPR type. In many cases, the product produced by such machines is too small for commercial use therefore, a separation baffle is added within the crystallizer to permit the removal of unwanted fine crystalline material from the magma, thereby controlling the population density in the machine so as to produce a coarser ciystal product. When this is done, the product sample plots on a graph of In n versus L as shown in hne P, Fig. 18-62. The line of steepest ope, line F, represents the particle-size distribution of the fine material, and samples which show this distribution can be taken from the liquid leaving the fines-separation baffle. The product crystals have a slope of lower value, and typically there should be little or no material present smaller than Lj, the size which the baffle is designed to separate. The effective nucleation rate for the product material is the intersection of the extension of line P to zero size. 

As long as the largest particle separated by the fines-destruction baffle is small compared with the mean particle size of the product, the seed for the product may be thought of as the particle-size distribution corresponding to the fine material which ranges in length from zero to Lj, the largest size separated by the baffle. 

High-speed, low-intensity drum magnetic separator. This device is designed to handle very fine material (minus 0.15 mm and finer) to produce a high-grade magnetic concentrate. 

Higher-circulating loads tend to increase production and decrease the amount of unwanted fine material. 

A difference between these firing methods may also be manifested in the initial fuel cost. For efficient operation of a spreader-stoker-fired boiler, the coal must consist of a proper mixture of coarse and fine particles. Normally, double-screened coal is purchased because less expensive run-of-mine coal does not provide the optimum balance oFcoarse and fine material. 

It has also helped that the bicycle buyer is continually offered more bicycle for less money. No longer are most bikes steel. While steel continues to be a fine material, the dominant material reported by bike enthusiast is now aluniinum, which, in the hands of most designers, yields a lighter but more rigid frame. 

Low-speed agitators These are suitable for systems not needing high turbulence. Large-diameter paddles or rakes may be used to mix slurries containing fine material... 

The fineness of the material being processed governs the selection of machines. Both the feed and the product sizes are involved in the selection process. Some machines, by their very design, can treat only coarse material, while some others can treat only fine material. Some machines produce a very uniform product, whereas some others, by virtue of their construction, produce a product with considerable variations in size. 

Complete reaction of explosives is important in obtaining the best results for both power development and fume avoidance. It is aided by the use of fine materials, but if this is carried too far other disadvantages of hardness and low density are introduced. 

The larger is the value of Sy, the stronger is the mutual synergistic interaction between the coarse and fine particles. Also, an effective fine particle additive to improve the fluidizing characteristics of coarse particles calls for a large value of m produced with minimal amount of the fine material, that is, a small value of x2. 

By combining the findings of Cacchione, Drake and the results reported here, a coherent model can be proposed to explain the deposition inventory of the radionuclides. The down-canyon current transports large quantities of sediment toward the radioactive waste disposal site at 4000 m. Within the upper canyon, fine material is transported the furthest. Near the mouth of the canyon, sediment erosion of the walls occurs due to the down-canyon currents meeting a proposed opposing on-shore bottom current. The eroded material from the walls is transported and the finer material is deposited in eddies formed where the two currents meet. 

Schwarzmiiller, J. Stettler, A. (1970). Trapped solar wind noble gases, exposure age and K/Ar-age in Apollo 11 lunar fine material. Proc. Apollo 11 Lunar Sci. Conf, 2,1037-70. 

In unstratified homogeneous soil, the form will be pear-shaped, with the larger part at the bottom. If the soil is stratified or contains significant fine materials, some horizontal spreading will occur. The general shapes that might be expected are shown in Figure 5.10. 

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