Substitution of materials

Several methods have received considerable research attention as alternatives to salt curing. These include use of sodium bisulfite as a disinfectant to allow preservation with or without decreased salt in a brine cure use of disinfectants such as quatenary amines for temporary preservation in direct shipping to the taimery from the packing plant (see Disinfectants and antiseptics) preservation of hides by radiation sterilization (see Sterilization techniques) and substitution of materials such as potassium chloride for sodium chloride. These methods have found only limited commercial success. 

Some recycling of metals occurs much more is possible, and substitution of materials requiring less energy for those requiring more has much potential. 

Substitution is a difficult task because the specific ingredients will control the application and end-use properties of the epoxy adhesive. Any substitution of material generally requires that the complete product be reverified with production and prototype testing. Of course, the health and safety issues of any alternative material must also be carefully considered to ensure that it is actually safer. 

The substitution of materials other than silicon or aluminum into the zeolite framework—particularly the phosphorus substitution reported by Flanigen and Grose. It was, however, disappointing that this was successful with only one large-pore material, namely, type L zeolite. 

CFR1021 48CFR970.5223-2 4.1.2 Substitution of materials that are less hazardous and/or have less of an environmental impact shall be evaluated before purchase. 

A favourite application is the substitution of materials for boxes in sound generation because the material is optimal for suppressing unwanted resonances and damping oscillations. 

New moulds may produce parts that are essentially flash free but gradually deteriorate with use. A low rate of wear depends upon the right choice of tool steel. This should be a grade that can be hardened by heat treatment but without any attending distortion. The design specifications of the mould must include details of the materials from which the mould cavities and the mould bolster will be made. Failure to understand the reasons behind the choices may lead to substitutions of materials that are thought to be similar, but in reality have significantly different properties. 

Chemical risks may also be controlled by effective ventilation, regular monitoring, substitution of material, change of process, purchasing controls, and the use of protective equipment. 

This involves the substitution of materials or operations in a process by safer alternatives. A toxic material may be replaced by another less harmful substance or in another context something less flammable. An example is the widespread replacement of carbon tetrachloride by other solvents such as dichloromethane and 1,1,1-trichloroethane. 

The group first considers and holds open the possibility of completely redesigning and replacing the process. Substitution of materials or methods is considered, and it is determined that action on such opportunities have already been taken. Safety devices and warning systems have been updated and are considered state of the art. Maintenance is considered superior. 

One of the most crucial aspects of green technology is the sustainable utilization of minerals. In a sense, the concept of sustainable mineral utilization is an oxymoron because minerals removed from the geosphere are not replaced. However, the idea of sustainability can greatly extend supplies of minerals. This section addresses the approach to sustainability in obtaining minerals. The broader questions of green utilization of materials, substitution of materials, and recycling are discussed in more detail in Chapters 14 and 16. 

Research is also needed to broaden the applications of polymeric materials. Materials with tailored properties based on blends, high-strength fibers, new matrices for composites, and improved stability of toughening additives are finding new uses as materials substitutes and in unique applications. This trend will accelerate as failure mechanisms become better understood. The areas for substitution of materials span automobiles, aircraft, boats, construction, machinery, and many other specialty items. While military applications are growing (e.g., body armor, uniforms, and aircraft), the field is ripe for rapid growth and penetration by polymeric materials. 

In the original Battelle study, almost 40 percent of 1975 metallic corrosion costs were attributed to the production, use, and maintenance of motor vehicles. No other sector accoimted for as much as 4 percent of the total, and most sectors contributed less than 1 percent. The 1995 Battelle study indicated that the motor vehicles sector probably had made the greatest anticorrosion effort of any single industry. Advances have been made in the use of stainless steels, coated metals, and more protective finishes. Moreover, several substitutions of materials made primarily for reasons of weight reduction have also reduced corrosion. Also, the panel estimated that 15 percent of previously unavoidable corrosion costs can be reclassified as avoidable. The industry is estimated to have eliminated some 35 percent of its avoidable corrosion by its improved practices. Table I.l summarizes the costs attributed to metallic corrosion in the United States in these two studies. 

In order to devise a safety culture and program that will actually work to protect chemical workers, we first must determine where the injuries and illnesses come from. Chemical hazards include any aspect of technology or activity that produces risk. The level of risk is primarily the combination of two factors the level of toxicity present and the degree of exposure. The level of toxicity is reduced by substitution of materials and design. Exposure is most effectively reduced through the use of engineering controls such as safety devices, enclosures, guards, and ventilation systems. 

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