Engineering design economic factors

First, achieving lower raw material cost than at present is always an important economic factor. When the price for one material comes down relative to another, the point at which we trade-off between the two materials changes because cost is a factor in most designs. That statement is not meant to imply that engineers are not concerned about cost in some designs, but we must emphasize that some particular structures have functional requirements as the most important issue. Can they or can they not do the job Cost is not the primary issue in that case. We would naturally like to have a less-expensive Space Shuttle, but can we do the job that the Space Shuttle is now doing with a lower-cost structure We could use less-expensive materials, but would they be able to hold up, would they survive reentry, and would the astronauts be able to survive If the astronauts would not be able to survive, then clearly you would acknowledge that we must pay the added cost to get the job done, i.e., to ensure their safety. 

The second part deals with applications of solvent extraction in industry, and begins with a general chapter (Chapter 7) that involves both equipment, flowsheet development, economic factors, and environmental aspects. Chapter 8 is concerned with fundamental engineering concepts for multistage extraction. Chapter 9 describes contactor design. It is followed by the industrial extraction of organic and biochemical compounds for purification and pharmaceutical uses (Chapter 10), recovery of metals for industrial production (Chapter 11), applications in the nuclear fuel cycle (Chapter 12), and recycling or waste treatment (Chapter 14). Analytical applications are briefly summarized in Chapter 13. The last chapters, Chapters 15 and 16, describe some newer developments in which the principle of solvent extraction has or may come into use, and theoretical developments. 

The design engineer must specify the diameter of pipe that will be used in a given piping system, and economic factors must be considered in determining the optimum pipe diameter. Theoretically, the optimum pipe diameter is the... 

When faced with the problem of selecting a plastic for a given purpose, a design engineer must be concerned with the properties of the material, the ease of processing or fabrication, the behavior under the environmental conditions to which the product will be subjected (i.e., the thermal range) and, of course, the economic factors. Each problem has to be treated as a specific case, and familiarity with structure-property relations aids the selection. The illustrations are limited to two widely differing aspects. 

In order to achieve a successful design with polymers, the engineer must pay proper attention to their unique physical and chemical properties, and to their special processing characteristics, whilst keeping economic factors in mind. When mistakes are made, they are usually due to ... 

Optimization of performance characteristics of textile products and processes is often the final stage in the engineering design where the results of experimental and theoretical modeUmg are combined in order to achieve the best possible combination of properties. In many cases this also includes consideration of economic and logistic aspects. It can be seen from the sections above that the process-structure-property system is governed by complex multi-factor relationships. In these conditions, the optimization problem can be formulated as a problem of finding a combination of independent factors X (optimal point) that provide an extremum... 

Hence, a number of factors, viz., geomorpho-logical, geological, geotechnical, engineering design, environmental, economics etc has to be considered before selection of powerhouse site in an immatured terrain, like Himalaya. 

Clearly, the knowledge and skill resources represented on a design team are critical to its success. However, as Trevelyan notes in Chapter Two in this book, there may also be social, economic, and political factors in play that require more than technical engineering expertise. Those factors, and others, lend importance to the thoughtful makeup of design teams. 

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