Demarcate engineering

Many thermoplastics are now accepted as engineering materials and some are distinguished by the loose description engineering plastics. The term probably originated as a classiflcation distinguishing those that could be substituted satisfactorily for metals such as aluminium in small devices and structures from those with inadequate mechanical properties. This demarcation is clearly artificial because the properties on which it is based are very sensitive to the ambient temperature, so that a thermoplastic might be a satisfactory substitute for a metal at a particular temperature and an unsatisfactory substitute at a different one. 

Ittner s analysis displays the familiar contrast between control and knowledge which often demarcated the engineer s work from that of the scientist. But, more specifically, it also denies any role to unit processes defined as chemical processes. For Ittner, the unit process, once it is examined closely, can be... 

There should always be kept in mind the definite line of demarcation between industrial chemistry, which is concerned with individual processes as entities in themselves, and chemical engineering, which focuses attention upon those unit operations common to many processes and the proper grouping of these unit operations for the production of the desired product as efficiently and cheaply as the ruling conditions permit [9]. 

Materials scientists and engineers have traditionally been primarily concerned with the fabrication and utilization of materials already synthesized by the chemist and identified by the physicist as having the appropriate intrinsic properties for a particular engineering function. Although the demarcation between the three disciplines remains in an academic sense, the separate job distinctions for those working in the field is fading. This is especially obvious in the private sector, where one must ensure that materials used in real commercial devices not only perform their primary function, but also meet a variety of secondary requirements. 

In spite of the foregoing limitations, the corrosion scientist and engineer can derive a wealth of information by consulting the relevant potential/pH diagrams. The regions of immunity, passivity, and pos.sible corrosion are demarcated, and the most common corrosion products are shown. Studying the relevant diagram is an excellent way to start a new corrosion study, but it. should never be the only tool used to solve the problem. 

We have seen how various parameters can be altered and combined to produce a material with given responses, but the lines of demarcation dividing polymers into the three major areas of apphcation — fibers, elastomers, and plastics — are by no means well defined. It is most important then to establish criteria that determine whether a polymer is a superior fiber, an excellent elastomer, or a particulariy suitable plastic before overindulging in the interesting stages of molecular design and engineering. 

The information most often required for engineering purposes is the lithological and structural information. These stratigraphic rock units or map units normally do not have different constituent rock types individually demarcated but these may be found mentioned collectivity in the legend. This tends to drastically limit their usefulness for engineering purposes. However, in spite of this limitation there is one map unit referred to as the Quaternary that does assist directly in engineering site investigations of sedimentary rocks. 

A lithological map showing the spatial distribution and demarcation of the contacts between the different rock types largely fulfils engineering needs. 

In the following several time dependent failure laws will be considered that can be used by the design engineer to make estimates of the probable time for rupture failure in uniaxial tensile tests. The section will conclude with a brief discussion of how to apply these approaches to more complicated structures. While the following methods have been developed primarily for a creep to rupture phenomenon, they can potentially be used for creep to yield as well or even possibly as a means of determining the demarcation between linear and nonlinear viscoelastic regimes. Some of the examples included are applied in this manner. 

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