The evolution of engineering is essentially a history of civilization. As early humans transitioned from a nomadic existence into settlements, there arose a need for permanent structures and systems for handling water and wastewater demands. Civil engineering developed in response to these needs, and even today one can marvel at the systems developed by engineers of ancient civilizations in Egypt, Mesopotamia, Indus Valley, and Ancient Rome. Figure 1.3 shows Pont du Gard—a bridge over the river Gard in France built by the Roman engineers nearly 2000 years ago [6]. The third tier of this impressive structure, 160 feet above the river, is an aqueduct supplying water to the cities [6, 7].
Figure 1.3 A Roman bridge with the upper tier functioning as an aqueduct.
Source: Hanser, D. A., Architecture of France, Greenwood Press, Westport, Connecticut, 2006.
Figure 1.4 shows the ruins of a sophisticated water reservoir from the city of Dholavira belonging to the Indus Valley Civilization dating several millennia further back. The cities and even smaller towns and villages of the Indus Valley Civilization feature a water and waste management system that can simply be described as outstanding [8].
Figure 1.4 Ruins of a water reservoir in Dholavira.
Source: Archaeological Survey of India, http://asi.nic.in/images/exec_dholavira/pages/015.html.
The second driving force for engineering development was the need for accomplishing things beyond what was possible through simple manual labor, leading to simple machines such as the Archimedes screw (Figure 1.5), a simple yet elegant machine for pumping water and transferring material. This simple machine is capable of lifting the fluid, even if it contains a small amount of debris [9]. These machines progressively increased in complexity with time, driven in no small measure by the need for advanced weapons and means of movement, leading to the discipline of mechanical engineering. This evolution has continued with new disciplines appearing over time in response to societal needs based on advances in sciences and new discoveries.
Figure 1.5 A schematic representation of the Archimedes screw.
Source: Chondros, T. G., “Archimedes Life Works and Machines,” Mechanism and Machine Theory, Vol. 45, No. 11, 2010, pp. 1766–1775.
The American Society of Engineering Education (ASEE, www.asee.org), as a part of its activities, compiles statistical data on engineering graduates by disciplines, degree levels (bachelor, master, doctorate), demographics, and various other criteria. Figure 1.6 shows the breakdown by discipline of more than 106,000 bachelor’s degrees in engineering awarded in 2014–15 [10]. Mechanical engineers form the largest group of engineering graduates, followed by civil, electrical, and chemical. These four disciplines are traditionally recognized as the big four of engineering, and any comprehensive school of engineering offers, at the minimum, degree programs in these four disciplines.
Figure 1.6 Bachelor’s degrees in engineering by disciplines in 2014–15.
Source: Yoder, B. L., “Engineering by the Numbers,” https://www.asee.org/papers-and-publications/publications/college-profiles/15EngineeringbytheNumbersPart1.pdf.
The emerging disciplines of engineering can also be identified from the figure. Computer science has the fourth-largest number of graduates, reflecting the explosive growth of information technology in recent times. However, it was not too long ago that most computer science programs were housed in colleges of science, typically as a part of the mathematics department. The last two decades have seen these programs migrating to the college of engineering, with their own department that does not include the word engineering in its name. Computer science is distinct from computer engineering, which is often associated with electrical engineering programs. The other emerging engineering field is biomedical engineering, which has evolved out of advances in biotechnology and biomedical sciences.
The following briefly describes the big four engineering disciplines—mechanical, civil, electrical, and chemical:
• Mechanical engineering, as the name indicates, deals with development, design, and operation of all types of machines and systems for human convenience and comfort. This is the broadest of the engineering disciplines, with mechanical engineers serving fields ranging from machine design, manufacturing, energy, transportation machines and materials, materials handling, refrigeration and heating systems, maintenance and biomechanics, and many others. Mechanical engineers are a ubiquitous presence in all industries.
• Civil engineering is the earliest discipline of engineering dealing with the development, design, construction, and operation of the facilities and structures for the society. These facilities range from buildings, dams, highways, and canals to all types of systems and infrastructures for mass transit, water supply, waste disposition, and so on. Civil engineering can be further subdivided into specializations such as construction engineering, transportation engineering, geotechnical engineering, water resources engineering, and so on [4].
• Electrical engineering is the discipline dealing with machines and systems associated with electrical energy. Electrical engineers are concerned with the generation and transmission of electricity and with electrical machines. With electricity replacing all other types of energy for practically all consumer applications with the exception of automobiles and cooking, electrical engineers are as ubiquitous as mechanical engineers. Within electrical engineering, one can find specializations such as electronics, controls and power engineering, and so on.
• Chemical engineering as a discipline grew out of industrial chemistry and the need to produce large quantities of chemicals economically. Detailed discussion of chemical engineering is presented in the following section.
The identification of these four as distinct and major branches of engineering is not based on numbers alone but also on the fact that subjects studied during undergraduate studies for each are distinct enough to warrant a separate curriculum. There is an inevitable content overlap between disciplines, particularly between mechanical and civil engineering related to fluid and solid mechanics [11]. However, even for the overlapping content, the approach and treatment of topics and educational objectives generally differ for different disciplines. An individual obtaining a bachelor’s degree in one of these disciplines will not be easily able to go on for graduate study in the other three disciplines without spending a substantial amount of time, perhaps equivalent to junior and senior years of a 4-year undergraduate degree program, completing prerequisite courses to address deficiencies. This is in contrast to the rest of the engineering disciplines seen in Figure 1.6.
With the possible exception of material and metallurgical engineering, an individual with a bachelor’s degree in one of the big four disciplines can successfully go on to pursue graduate studies in many of the other engineering disciplines without needing substantial additional coursework to satisfy prerequisites. A civil, mechanical, or chemical engineer can go on to study and practice environmental engineering. A mechanical engineer can become an industrial, manufacturing, aerospace, or nuclear engineer. Similarly, a chemical engineer can pursue nuclear, biological/agricultural, or petroleum engineering graduate degrees. Many engineers, particularly over last two decades, have changed their fields to computer science at the graduate level. Many biomedical engineering programs operate only at the graduate level, admitting students with undergraduate degrees in mechanical or chemical engineering.
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