Abstract: A sensor for detecting the presence of a particular chemical by determining the absolute frequency shift in the oscillating frequency of an antibody-coated oscillator. Specific antibodies deposited on a high Q crystal oscillator detect the change in frequency as chemical particulates become trapped by the antibodies and change the effective mass of the crystal. In one embodiment, two oscillating crystals are used, one that has been coated with the antibodies, and one that is uncoated. This permits detection of frequency differences between the oscillating frequencies of the two crystals, thus eliminating pressure, temperature, and humidity corrections that conventionally must be made. The sensor maintains a high specificity by using antibodies that are specifically related to the chemical to be detected, while achieving relatively good sensitivity by using high Q oscillators, such as quartz or sapphire, and eliminating drift problems due to temperature, pressure, and humidity.

Abstract: A semiconductor-to-metal optical switch or device for power limitation in the infrared spectral region includes two thin semiconductor layers sandwiched between two transparent electrodes. An electrical voltage is applied across the two semiconductor layers to produce an active device for blocking incident light in the 8 to 12 .mu.m spectral region. The material composition and thickness of the two semiconductor layers are such that enough photo-excited electrons are generated in the first semiconductor layer so that the second semiconductor layer undergoes a rapid semiconductor-to-metal transition at a predetermined light intensity. The semiconductor layers remain transparent below the predetermined light intensity and the second layer will become metal-like at a light intensity above a threshold level. Upon becoming metal-like, the second semiconductor layer will block the incident light.

Abstract: A method and apparatus (66, 72, 74) is disclosed which allows for the measurement of a concentration of hopeite and phosphophyllite contained within a zinc phosphate coating material (64). Specifically, the method employs Raman spectroscopy and measures the aforementioned concentration in an on-line and non-contact manner.

Abstract: An apparatus and method for measuring the conductivity of a fluid. The apparatus 10 provides both a contact and non-contact monitoring of fluid conductivity by measuring the A.C. dielectric properties of the fluid. The apparatus 10 transmits an electromagnetic wave into the fluid 22 and analyzes the transmitted and reflected waves providing an indication of the conductivity of the fluid 22. The apparatus 10 is versatile in that it allows for the fluid to be in the form of a spray. In a specific illustrative implementation, a novel nozzle is provided to monitor the conductivity of paint spray 22 as it passes therethrough.

Abstract: A method and apparatus for non-contact measurement of the viscosity of a liquid such as paint. In accordance with the method and apparatus, the surface of a liquid is perturbed with a standing wave of predetermined wavelength. This perturbation is effected by directing a burst of air against the surface of the liquid using periodically spaced air nozzles. The frequency and rate of decay of the induced surface wave is measured using typically optical means including a reflected light beam. The measured frequency and decay rate are combined with the known depth of the liquid sample in a computing circuit to provide a measurement of fluid viscosity.

Abstract: An eye protection device against broadband high intensity light sources, including a fast response component (picosecond to microsecond) and a slow response component (microsecond and longer). The fast response component consists of two thin semiconductor layers "sandwiched" between two transparent electrodes. The natures and dimensions of the semiconductor layers and the voltage bias applied to them are determined such that enough photo-excited electrons are generated in the first small bandgap layer so that the second large bandgap layer undergoes a rapid insulator-to-metal transition at the light-intensity threshold for eye damage. Upon becoming metal-like, this layer blocks the incident light. Below the damage threshold, the fast response component is transparent. The slow response component includes a PLZT (lanthanum-modified lead zirconium titanate) or similar electro-optic shutter. This component is transparent below the damage threshold.