In ultrasonic processing, it has been a practice to measure intensity of ultrasonics as a product of plate current and voltage as indicated on ultra sonic generator. At low frequencies the standard equipment is available, such as the sound level meter, to measure the absolute intensity, but at higher frequencies the problem becomes complicated by the diffraction effects on account of the size of the measuring device. In this investigation an attempt has been made to construct a measuring device (called the probe) to measure intensity. A small barium titanate cylindrical element (1/16 inch in diameter and 1/16 inch length) was used as a detector-convertor of sonic pressures. The alternating voltages thus produced were indicated by a vacuum tube voltmeter. This element was cemented in a hypodermic needle in turn was held in a lucite rod (1/2 inch in diameter and five inches in length) which served as a holder. This arrangement was used to probe the sonic fields of cylindrical and bowl shaped transducers. / Ph. D.

Instrumentation has been designed to process the signals from two types of skin friction gages and a microfabricated heat flux gage. Design changes for the skin friction gages are presented which will improve the performance of the two transducers. The instrumentation is simple in design and use and has been designed to maximize the performance of the skin friction and heat flux gages. The instrumentation is battery powered to minimize noise levels and to maintain instrumentation portability. A high-quality instrumentation amplifier, a voltage regulator, and a custom-designed circuit board have been combined to produce an instrumentation package which is stable and durable. The instrumentation has been specifically designed to handle low-level signals and can operate over a wide range of frequencies. Problems commonly associated with low-level signal conditioning like electrical noise, nonlinearities, and output drift are addressed. The performance specifications of the instrumentation are presented along with sample gage measurements. / Master of Science