 498  182. Audio current through the coil varies the magnetic flux in the gap and causes the disk to vibrate and produce sound. The operating principle is much the same as that of the magnetic headphone, although the physical construction is somewhat different. The variable-reluctance headphone gets its name from the changes in reluctance of the magnetic path as the metal disk vibrates. Only one manufacturer currently produces a headset of this type. 183. The objective of the studies which are the subject of this report was to determine whether young mice of inbred strains predisposed to a high incidence of spontaneous leukemia characteristically manifested an immunologie defect in their RES which conferred upon them, concomitantly, a unique susceptibility to experimental infection, or whether mice destined to manifest leukemia were characterized by an initial hyperactivity of the RES which correlated with the occurrence of leukemia in later life. 184. The operation of much of the TIROS I instrumentation is subject to ground control. Thus, a means is available to determine from the ground the total instrumentation energy requirements in a given orbit. During orbits in which ground illumination is unsatisfactory for taking television pictures or the satellite is out of communication range of the two ground stations, little or no equipment was programmed and the major power drain was the continuous load. 185. Transducers commonly in use today utilize magnetostriction, or piezoelectricity. The former causes a slight variation in the length of a metal rod due to an alternating magnetic field in the direction of the axis of the rod. The latter is liberally pressure electricity which utilizes the property of a crystal to generate a voltage when mechanical force is applied, and conversely produces a mechanical force by expanding or contracting when a voltage is applied. 186. In any case, the presently unknown materials constitute only a small portion of the urinary metabolites of N-2-fluoreny-lacetamide, although the elucidation of their nature and structure is a problem of fundamental interest. In addition, some of the unknown compounds could be derived from the breakdown of carcinogen-protein complexes so that a knowledge of their composition may yield some important clue as to the nature of the carcinogen protein interaction. 187. The process of arriving at the correct frequency is not completely random, since the magnitudes of the capacitor discharges become progressively smaller as the correct oscillator frequency is approached. The speed of correction depends on the rate at which the switch operates. 498 |
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