A manipulator or mechanical arm involves an upper and a lower arm, with a variable angle between them. Cables used to transmit motion and force from the upper to the lower arms pass over a pulley at the joint or elbow. A pulley, axiaily fixed with respect to the joint, imposes a change in length of the cable as the angle between the arms varies. Manipulation design requires a cable of constant length during this variation; this constant length may be achieved by guiding the center of the pulley along the proper path. Acceptable solutions were obtained in terms of variables such as the lengths of each arm, the radius of the pulley, and the angle between the arms. In one design the pulley center is moved along a straight line with respect to the lower arm, while in the other solution the pulley center is moved along a circular arc with respect to the upper amn. Practical and economical mechanisms based on these solutions were investigated for use in manipulator design. (auth)

The products from the flssion of U induced by charged particles were studied in a mass spectrometer. Both U/sup 238/ and U/sup 235/ were bombarded with 45.7- and 24-Mev helium ions, and U/sup 238/ was also bombarded with 730-Mev protons and 100-Mev carbon ions. Tbe total chain-yields in the region of the rare-earth elemerts (mass 140 to mass 155) for most of the above bombardments and a thermal-neutron bombardment of U/sup 235/ were studied by using the isotopicdilution technique. Independent yields were measured for all the above bombardnnents for several shielded nuclides. (auth)

The range and range straggling of 96.8-kev Ra/sup 224/ recoil atoms produced by alpha decay of Th/sup 228/ have been measured in H/sub 2/, D/sub 2/, He, N/sub 2/, Ne, and Ar by a charged, parallelplate, collection technique. The range and range straggling of 725-kev Th/sup 226/ recoii atoms produced by bombardments of Ra/sup 226/ with 41.6-Mev helium ions have been measured in D/sub 2/, He, N/sub 2/, and Ar by this same technique. Experimental results seem to indicate that the range-energy relation for the stopping of heavy recoils by nuclear collisions is not linear, as is theoretically predicted by Bohr. The distribution of ranges about the mean range appears to be Gaussian. Various factors contributing errors to the measured range stragglings are discussed in detail P coil efflciencies of the heavy recoils produced in the (d,) (d,2n), (d,3n), and (d,p) reactions of Bi/sup 209/ have been measured at incident deuteron energies of 15 0 to 23.6 Mev for Bi/sup 209/ targets of 0 6 to 42.5 mu g/cm. The recoil effic encies of the different reaction products have been compared on the basis of probable nuclear-reaction mechanism by which they are produced. Mean ranges for Po/sup 208/ in Bi/sup …