a occurring directly under the same bomb at the optimun height for a 10 pound overpressure. (3} Analysis of the relationship of geometrically scaled models and prototype structures is promising and may well lead to useful methods of predicting damage from scaled models, | LO, b, For a more detailed discussion of Program 3.0, sec Appendix "C", PROGRAM 4.0 — CLOUD PHYSICS a. Program 4,0 was concerned in a broad sense with the measurement and documentation of the various properties of the atomic clouds, thcir size, appearanco, electrical and radioactive characteristics, temperature, turbulence, water content, wind velocities, vertical. and horizontal mixing, rate of growth, dispersion charac— teristics and also the related ficld of tropical meteorology. were obtained in all phases of the program. Significant results Several of the most important results from the standpoint of strategic and tactical application of the weapon are: (1) It appears that a far greater than expected portion of the radioactivity is carried on particles of nonfilterable (submicron) size, This find- ing focuses attenblon upon the difficulty of filtering air for pressurized crew spaces in strategic and tactical aircraft. (2) The order of magnitude obtained for velocity of the afterwind indicates that past thinking and conclusions have greatly overemphasized the import- ance of this phenomenon, (3) Results obtained on the water content of atomic clouds indicate that "seeding" (dry icc, silver iodide, ete.) of an atomic cloud is not feasible (4) Sxtremely valuable data and experience in the field of tropical weather forecasting was obtaincd, Recently developed analysis techniques show promise, b. 11. For a more detailed discussion of Program 4.0, see Appendix "D", PROGRAM 5.0 ~ RADIAC INSTRUNENT EVALUATION The objective of Program 5,0 was to evaluate all ground and air radiac (Radiation Detection, Indication and Computation) equipment currently available as service or experimental itoms, to the end that improved equipment for military and civil defense applications may be designed and produced. Nineteen types of dosi- meters, sixteen types of survey meters, three types of laundry monitors, and one mobile radiological field laboratory wore tested, No individual dosimeter was found to be enbircly adequate and there was little correlation between types. Several