Optimum viscosity/cost

The usual work-up procedure of the reaction mixture made with Fe -KlO under optimum conditions (Table 2) resulted in 4 Ac-B15C5 with 55% yield. This result gives a practical preparative method which is really competitive with the 65-70% yield of the P2O5 or polyphosphoric acid acylation methods and eliminates their drawbacks difficult handling and mixing because of high viscosity, costly neutralization. 

Monomers. A wide variety of monomers can be used, and they are chosen on the basis of cost and abiUty to impart specific properties to the final product. Water solubiUties of iadustriaHy important monomers are shown ia Table 1 (38). The solubiUty of the monomer ia water affects the physical chemistry of the polymerization. Functional monomers like methacrylic and acryUc acid, infinitely soluble ia water, are also used. These monomers impart long-term shelf stabiUty to latices by acting as emulsifiers. The polymerization behavior of some monomers, such as methacrylic acid, as well as the final latex properties are iafiuenced by pH. For optimum results with these acids, polymerization is best performed at a pH of ca 2. After polymerization, the latex is neutralized to give adequate shelf stabiUty at tractable viscosities. 

Because of the complexity of designs and performance characteristics, it is difficult to select the optimum atomizer for a given appHcation. The best approach is to consult and work with atomizer manufacturers. Their technical staffs are familiar with diverse appHcations and can provide valuable assistance. However, they will usually require the foUowing information properties of the Hquid to be atomized, eg, density, viscosity, and surface tension operating conditions, such as flow rate, pressure, and temperature range required mean droplet size and size distribution desired spray pattern spray angle requirement ambient environment flow field velocity requirements dimensional restrictions flow rate tolerance material to be used for atomizer constmction cost and safety considerations. 

The relation between cost per unit length C of a pipeline installation and its diameter d is given by C = a + bd where a and b are independent of pipe size. Annual charges are a fraction of the capital cost. Obtain an expression for the optimum pipe diameter on a minimum cost basis for a fluid of density p and viscosity p flowing at a mass rate of G. Assume that the fluid is in turbulent flow and that the Blasius equation is applicable, that is the friction factor is proportional to the Reynolds number to the power of minus one quarter. Indicate clearly how the optimum diameter depends on flowrate and fluid properties. 

This evaluation illustrates that emulsion water concentration should generally be reduced until the viscosity begins to be significantly increased. In selecting the actual optimum concentration for a specific case, other factors such as the effect of water concentration on emulsion stability, the effect of total fiow rate on pump efficiency, and the cost and availability of water should also be considered. 

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