Abstract: A drive circuit having two electronic switches formed from N-MOS transistors is designed to alternatively connect the input of a preamplifier stage to a first or second read sensor on the read head of a magnetic tape. The drive circuit also has a third electronic switch formed from an N-MOS transistor which grounds the input of the preamplifier stage. Based on logic input signals, a control circuit switches the first and second switches, or closes the third switch and simultaneously opens the first and second switches.

Abstract: An infrared laser system includes a neodymium laser for generating a pulsed laser beam at a wavelength of 1.06 micrometers and a Raman cell containing a Raman active medium. The laser beam, having sufficient peak power to cause emission of light from the Raman active medium by stimulated Raman scattering, is directed through the Raman cell. Ethanol-d.sub.1 or methanol-d.sub.1 is used as the Raman active medium to generate wavelengths of about 1.5 micrometers, 2.8-2.9 micrometers, or both. The laser is preferably a neodymium YAG laser.

Abstract: An artificial intelligence software shell for plant operation simulation includes a blackboard module including a database having objects representing plant elements and concepts. A rule-based knowledge source module and a case-based knowledge source module, in communication with the blackboard module, operate on specific predefined blackboard objects. An input data module, in communication with the blackboard module, enables a user to input data to the shell. A control module, in communication with the knowledge source modules and the input data module, receives all input data and controls operation of the knowledge source modules in accordance with a predetermined knowledge source interruptibility/priority scheme. The control module including an event detector module having a hash table defined by a chaining algorithm.