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Typescript (photocopy). / Digitized by Kansas Correctional Industries

Call number: LD2668 .T4 1956 W47 / Master of Science

QC 351 A7 no. 20 / The control system described in this thesis was designed to automatically guide the position of photographic plates during long exposures of astronomical objects. The system senses the position of the guide star which is being used as a position reference, and moves the photographic plate in two orthogonal directions in order to maintain a constant position of the image of the astronomical object on the photographic plate. The system was designed to have a bandwidth of 35 radians per second in order to track the worst case image excursions due to atmospheric turbulence and telescope motion. The closed loop transient response of the system was determined from considerations of final image resolution of the photographic plate. Due to the necessity of guiding on stars of unknown brightness the system incorporated an automatic gain control loop within the forward control loop and was made unconditionally stable by high order feedback. In operation on the Steward Observatory telescopes, the system has made a significant increase in photographic plate resolution over manually guided plates.

Fifteen three-, four-, and five-year olds were assessed for the amount of time they spent on, off, under, and touching play equipment in an environment with play events and one without (i.e. the platform condition), An ABAB experimental design was used. Treatments lasted 3 days a week for 4 consecutive weeks, with each age group being videotaped 20 minutes each day, Data collected from the videotapes was applied to a 3 x 4 (age x treatments) ANOVA and revealed at the . 05 level (a) significantly more on and touching in the play event conditions; (b) significantly greater off and under in the platform (non play event) conditions; (c) a significant increase in off behavior from the first to second play event condition; (d) three-year-olds spent more time under and touching, and significantly less time on; and (e) significant interactions for on and under which seemed to be caused by the three-year-olds showing an inordinate amount of under behavior in the second platform condition, These results supported the assumption that play events would cause a significant increase inactive child-equipment interaction.