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The theory and design of microwave generators horns

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The theory and design of microwave generators, horns, antennas, detectors and display systems had been developed for long distance ranging in radar. Many textbooks presented the electromagnetic theory of microwaves in terms readily used by electrical engineers. Microwave system components and electron tubes were commercially available. However, electrical engineers were rarely aware of the needs of nondestructive testing engineers, and nondestructive testing engineers had little familiarity with microwaves. In fact, many nondestructive test personnel were still just beginning to use and understand eddy current testing at the lower frequencies. After several years of diligent development, continued application research and marketing efforts by Richard Hochschild with the assistance of Ronald Botsko, the pioneer organization Microwave Instruments Company was sold and its proprietor moved to the area of medical services. A few other organizations built simple microwave test systems but the development of industrial microwave nondestructive testing languished during the 1970s. Limited research sponsored by government agencies resulted in possibilities for crack detection from a distance. The theory of microwave antennas and of time domain reflectometry of microwaves in tubes, passing along wires and reflecting and refracting in dielectric layers, promises the possibility of valuable nondestructive testing applications. Because microwaves can be focused, microwave systems could be designed to operate in a manner analogous to optical instruments and ultrasonic systems. A large scale example of microwave exploration of test objects at great distances is occurring in radio astronomy laboratories throughout the world. Many radio signals from objects billions of kilometers away have been confirmed by films from optical telescopes and the locations of others have been predicted. Emissions are detected from galaxies, black holes and other astronomical features. J.D. Kraus has recognized this as a form of nondestructive testing of outer space and has written a biographical book called The Big Ear, 17 which clearly and simply summarizes a lifetime of study and applications of Maxwell’s theory of electromagnetic fields. 40 Electromagnetic Testing
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1. McMaster, R.C. “The Origins of Electromagnetic Testing.” Materials Evaluation. Vol. 43, No. 8. Columbus, OH: American Society for Nondestructive Testing (July 1986): p 946-956. 2. McMaster, R.C. Section 1, “Introduction to Electromagnetic Testing.” Nondestructive Testing Handbook, second edition: Vol. 4, Electromagnetic Testing. Columbus, OH: American Society for Nondestructive Testing (1986): p 2-12. 3. Millikan, R.A. “Early Views of Electricity.” Electrons (+ and –), Protons, Photons, Neutrons, and Cosmic Rays.
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  • Fall '19
  • Magnetic Field, James Clerk Maxwell, Nondestructive testing, History of Electromagnetic Testing

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