Order number “set 5 with 1OFRICIAEUSE ONLY page 31 950. ABSTRACT At Operation Redwing, fallout sampling was conducted by arrays or groups of similar c@llecting instruments. Each array was located on the 'periphery of an elevated and circular wind-shielded platform designated as the standard platform. A correlation of the sampling variations in the amounts of fallout collected within the platforms was accomplished by the analysis of the collection data and the platform’s air-flow characteristics. With a single-wind system the amount of fall-out collected in the upwind part of the platform was lower than that collected in the downwind section and the collections around the platform varied symmetrically with respect to the wind direction. With a multi-wind system, similar characteristics were exhibited about a reference direction which was correlated to the variability of wind directions and associated fallout amounts by a vector summation. The extent of sampling variation or collection bias in both systems can be defined by certain parameters. For each platform the values of these parameters were obtained from the properties of a collection curve describing the variation around the platform. Collective curves of both systems were completed by interpolation and their notable aspect is that they resemble sine curves. At the only land station the sampling data between the platform 801. Item KEYWORD (S) collection and the associated collection on the ground was too limited for extrapolation to other systems. Sampling relationships between platform collection and associated ground collection are described for the Single-wind system but not for the multi-wind system. At the ship stations the equivalent ground value of the platform collections i.e., the value that would be collected by the earth’s surface, could not be determined; however, the weighted mean values of some of these platform collections are presented. 10 references. REDWING/fallout ;FALLOUT/sample collection ; REDWING; FALLOUT; WIND; SAMPLING; AIR SAMPLERS 55 150. REPORT NUMBER SC-~2090 (Tr) 110. PRIMARY TITLE (M) Natural frequencies of structure 3.1.1 70. PERSONAL AUTHOR (M) Jacobsen, L.S.; Wells, W.M. 710. CORPORATE SOURCE Sandia Corp., Albuquerque, NM (USA) a 371. PUB. DATE (YYMMDD) 511102 34. CLASSIF. LEVEL TEXT Official Use Only 950. ABSTRACT Preshot and postshot measurements of the natural frequencies of the seven buildings comprising structure 3.1.1 were made using a mechanical shaker and pickups measuring displacements. Using these measurements it was 9003405 OFFICIAL USE ONLY