Abstract: There is disclosed a method and apparatus for testing inflated vehicle tires to determine internal physical characteristics such as tire pressure. The apparatus includes a waveform transceiver for subjecting a tire to be tested to a transmitted waveform and for transmitting an ultrasonic waveform from a location external to the tire under test and for receiving the ultrasonic waveform from a tire under test at a location external thereto; and a processor for interpreting the received waveform with reference to the decay or attenuation of the amplitude of the waveform with time to provide a measure of the internal physical characteristic.

Abstract: A method and apparatus for instantaneously measuring the level of carbon dioxide (and other gases) in automotive combustion exhaust analysis is provided in the form of a portable battery driven roadside diagnostic instrument in which the CO.sub.2 level is measured by a calorimetric technique utilizing light as the energy source and a piezoelectric bimorph to vibrate a single fiber-optic element to multiplex between two fiber-optic receptors delivering the light to a measurement cell and a reference cell. The measurement cell comprises a salt of an acid-base indicator dye which provides proportional color change on contact with CO.sub.2. The dye is supported on a polymetric film in the cell.

Abstract: Gas analysis apparatus particularly applicable to the quantitative monitoring of individual gas components in automotive exhausts, and providing this function in a rapid-response and hand-held, low power consumption format, comprises an array of electrically responsive solid-state sensors to which the mixture of automotive gases to be analyzed is simultaneously fed. Monitoring the electrical response of the sensors enables a substantially instantaneous determination of the quantitative presence of individual components of the gas mixture.