Segregation reducing

Buildings must be designed with regard to the needs for manufacturing with minimum risk of contamination. There must be demarcation of areas for different activities. Such segregation reduces the possibility of contamination and materials mix-ups. 

Wastes are mainly divided into two types hazardous and nonhaz-ardous. A proper segregation reduces the volume of hazardous waste by preventing the mixing of hazardous and nonhazardous wastes. The separation of hazardous waste from nonhazardous can significantly reduce the quantity of one kind of waste, which in turn reduces the treatment or disposal cost. Moreover, this waste can be reduced or sent to an onsite or off-site treatment plant for recovery. 

In high permeability reservoirs, wells may produce dry oil for a limited time following a shut-in period, during which gravity forces have segregated oil and water near the wellbore. In fields with more production potential than production capacity, wells can be alternately produced and shut in (intermittentproduction) to reduce the field water cut. This may still be an attractive option at reduced rates very late in field life, if redundant facilities can be decommissioned to reduce operating costs. 

Slag and Htharge formed during cupeUation are segregated and reduced to a metal containing 20—25% ore more bismuth, depending on the bismuth content of the original buUion, and transferred to a bismuth recovery plant. 

Funnel flow bins are only suitable for bulk soHds that are coarse, free flowing, and do not degrade, and for use when segregation is not important. For such materials, the principal benefits of funnel flow bins are reduced headroom and lower initial cost for the bin (excluding feeders or dischargers). Examples of funnel flow bins are shown in Figure 2. 

Another technique is to change the particle size distribution. There are, however, disadvantages. If segregation is occurring by the sifting mechanism, the particles must be almost identical in size before sifting is prevented. Alternatively, the mean particle size can be reduced below 100 p.m, but this size reduction (qv) increases the probabiUty of segregation by the too fine powder mechanisms. 

Fig. 6. An iategrated approach to the management of municipal soHd waste (MSW), advocated by the U.S. EPA, that links source segregation, recycling, waste-to-energy (WTE), and landfilling ia a single system. Source segregation refers to the separation of compostable and recyclable components from the balance of the trash at the poiat where MSW is collected. In source reduction (not shown), another action to reduce waste to landfills, changes are made ia...

An ingenious method to avoid or reduce segregation of alloying elements involves preparing small spheres of material by the atomization of a Hquid stream through a nozzle to produce a powder. This powder can be compacted, often hot and triaxially by gas pressure, to form a material where, on further heating, the residual pores close by diffusion to approach 100% density. 

Thus the addition of an inert gas which does not intervene chemically in the uansport reaction but adds to the density of die gas, reduces the segregation due to thermal diffusion. An example of this is the reduction of tlrermal separation in a mixture of H2 and H2O by the addition of Hg vapour (Dastur and Chipman, 1948). 

Many of these problems can be solved by using continuous casting (Fig. 14.3). Contraction cavities do not form because the mould is continuously topped up with liquid metal. Segregation is reduced because the columnar grains grow over smaller distances. And, because the product has a small cross-section, little work is needed to roll it to a finished section. 

Recent advances in accelerator technology have reduced the cost and size of an RBS instrument to equal to or less than many other analytical instruments, and the development of dedicated RBS systems has resulted in increasing application of the technique, especially in industry, to areas of materials science, chemistry, geology, and biology, and also in the realm of particle physics. However, due to its historical segregation into physics rather than analytical chemistry, RBS still is not as readily available as some other techniques and is often overlooked as an analytical tool. 

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