ENGINEERING

the application of science to the optimum conversion of the resources of nature to the uses of humankind. The field has been defined by the Engineers Council for Professional Development, in the United States, as the creative application of scientific principles to design or develop structures, machines, apparatus, or manufacturing processes, or works utilizing them singly or in combination; or to construct or operate the same with full cognizance of their design; or to forecast their behaviour under specific operating conditions; all as respects an intended function, economics of operation and safety to life and property. The term engineering is sometimes more loosely defined, especially in Great Britain, as the manufacture or assembly of engines, machine tools, and machine parts. The words engine and ingenious are derived from the same Latin root, ingenerare, which means to create. The early English verb engine meant to contrive. Thus the engines of war were devices such as catapults, floating bridges, and assault towers; their designer was the engine-er, or military engineer. The counterpart of the military engineer was the civil engineer, who applied essentially the same knowledge and skills to designing buildings, streets, water supplies, sewage systems, and other projects. Associated with engineering is a great body of special knowledge; preparation for professional practice involves extensive training in the application of that knowledge. Standards of engineering practice are maintained through the efforts of professional societies, usually organized on a national or regional basis, with each member acknowledging a responsibility to the public over and above responsibilities to his employer or to other members of his society. The function of the scientist is to know, while that of the engineer is to do. The scientist adds to the store of verified, systematized knowledge of the physical world; the engineer brings this knowledge to bear on practical problems. Engineering is based principally on physics, chemistry, and mathematics and their extensions into materials science, solid and fluid mechanics, thermodynamics, transfer and rate processes, and systems analysis. Unlike the scientist, the engineer is not free to select the problem that interests him; he must solve problems as they arise; his solution must satisfy conflicting requirements. Usually efficiency costs money; safety adds to complexity; improved performance increases weight. The engineering solution is the optimum solution, the end result that, taking many factors into account, is most desirable. It may be the most reliable within a given weight limit, the simplest that will satisfy certain safety requirements, or the most efficient for a given cost. In many engineering problems the social costs are significant. Engineers employ two types of natural resourcesmaterials and energy. Materials are useful because of their properties: their strength, ease of fabrication, lightness, or durability; their ability to insulate or conduct; their chemical, electrical, or acoustical properties. Important sources of energy include fossil fuels (coal, petroleum, gas), wind, sunlight, falling water, and nuclear fission. Since most resources are limited, the engineer must concern himself with the continual development of new resources as well as the efficient utilization of existing ones. the application of scientific principles to the optimal conversion of natural resources into structures, machines, products, systems, and processes for the benefit of humankind. Engineering is one of the oldest professions in the world; there are a plethora of examples of spectacular engineering feats dating back to ancient times, the best known being the pyramids of ancient Egypt. There are traditionally four primary engineering disciplines, namely civil, mechanical, electrical, and chemical engineering, each of these having several distinct specialized branches. Other important and distinct engineering disciplines are concerned with mining, nuclear technology, and environmental control. The oldest of the four main disciplines is civil engineering, which developed from techniques used in the ancient world. It is concerned with the design, site preparation, and construction of all types of structures and facilities, such as bridges, roads, tunnels, harbours, and airfields. Most of the projects involving civil engineering are undertaken by the public sector and are concerned with the development of urban, regional, and national infrastructures. Within the overall context of civil engineering there are several specialized branches, such as structural engineering, foundation engineering, public health and sanitary engineering, and irrigation engineering. Municipal and traffic engineering are more recent specializations. The spread of the Industrial Revolution in the first half of the 19th century resulted in the evolution of mechanical engineering as a distinct discipline that is concerned with the design, development, and testing of all types of industrial machinery and engines. This discipline has likewise evolved into many diverse specializations, such as automotive, aeronautical, and marine engineering. Precision engineering and production engineering are other important subdisciplines of mechanical engineering, as is agricultural engineering. Electrical engineering, covering the design and installation of main electrical systems, evolved during the latter part of the 19th century, when electrical technology began making rapid strides. Since that time, various specialties within the electrical-engineering spectrum have emerged, such as electronics engineering, communications engineering (which includes radio and television), and instrument engineering. More recent specialties within the electrical-engineering field include medical engineering and computer engineering. The newest of the four basic engineering disciplines is chemical engineering. Although the basic concepts were propounded a century ago, the main stimulant to its evolution was the development of the oil industry and the use of oil-derived products as raw materials for the chemical industry over the last 50 years or so. The discipline is concerned with the design of processes and equipment for the large-scale conversion of petroleum components by means of chemical reactions; its specialty areas include process engineering and petroleum engineering. Chemical engineering differs from the other three major classes of engineering in that it adds a third science (chemistry) to the two cornerstones of engineering, mathematics and physics. Between these diverse fields of engineering there is inevitably some overlap of interest and expertise. It is, however, common to all branches of engineering that academic training must begin with a thorough grounding in the fundamental principles of science, particularly mathematics and physics. Education may then be continued in general engineering subjects, including draftsmanship. There is naturally a differing emphasis in these subjects according to the branch of engineering selected by the student. All engineers must have a positive interest in the translation of the theoretical into the practical. Not only is an appropriate basic academic qualification necessary to enter the profession but a considerable period of time must be spent in gaining practical experience before the engineer can be considered properly qualified in the profession. Engineers of some kind can be found in virtually every type of manufacturing and processing industry appropriate to their skills, as well as in public service and in many of the service industries. However, there are considerable variations in the definition and status of the professional engineer among different countries, these being due primarily to historical reasons. Whereas in many countries (such as Germany and the United States), the engineer may be accorded a professional status similar to that of a lawyer or a physician, in others until the late 20th century the term engineer was synonymous with that of a mechanic. Additional reading Works on the history of engineering in general include A.P.M. Fleming and H.J. Brocklehurst, A History of Engineering (1925); Richard Shelton Kirby et al., Engineering in History (1956, reprinted 1990); James K. Finch, The Story of Engineering (1960); Donald Hill, A History of Engineering in Classical and Medieval Times (1984); and E. Garrison, A History of Engineering and Technology: Artful Methods (1991). Histories of the engineering profession in the United States include Edwin T. Layton, Jr., The Revolt of the Engineers: Social Responsibility and the American Engineering Profession (1971); David F. Noble, America by Design: Science, Technology, and the Rise of Corporate Capitalism (1977); Monte A. Calvert, The Mechanical Engineer in America, 18301910 (1967); and A. Michal Mcmahon, The Making of a Profession: A Century of Electrical Engineering in America (1984). General descriptions of the engineering profession may be found in Theodore Jesse Hoover and John Charles Lounsbury Fish, The Engineering Profession, 2nd ed. (1950); and Ralph J. Smith, Blaine R. Butler, and William K. Lebold, Engineering as a Career, 4th ed. (1983). Richard C. Dorf (ed.), The Engineering Handbook (1996), is an extensive reference work. Ralph J. Smith The Editors of the Encyclopdia Britannica