"This symposium is concerned with the basic aspects of radiation effects. When we turn to the genetic effects of radiation in mammals, there are so few aspects on which there is any information that the problem of sorting out the fundamental findings has hardly arisen. In this paper it will, therefore, be possible to survey most of what is known and pass on to a consideration of what is needed next. Since one of the purposes of this symposium is an interchange of views between investigators in different fields, an attempt will be made to avoid technical details. Among the practical needs in mammalian radiation genetics is a pressing one for more data on which to base estimates of the genetic hazards of radiation in man. The present paper will be concerned largely with this problem. Our own work is directed primarily in this direction, our objective being to uncover some of the basic facts in at least one mammal-the mouse. Before discussing the experimental work, however, it seems desirable to consider some of the general features of the genetic hazard of radiation."

Performance characteristics of a two-dimensional isentropic diffuser have been experimentally determined at a Mach number of 3.85. At zero angle of attack, a maximum total-pressure recovery of 0.41 was obtained with a supercritical mass-flow ratio of 0.95. As a consequence of the twin-duct arrangement of the diffuser, a large discontinuity in pressure recovery and mass flow with a characteristic hysteresis was encountered between critical and subcritical operation. An asymmetric shock pattern with large-scale separation and flow reversal in one of the passages occurred at reduced mass flows. Pressure and force data presented for an angle-of-attack range from zero to 4 degrees.

Memorandum presenting minimum spark-ignition engines at reduced pressures for ethane, ethylene, acetylene, n-hexane, cyclohexane, and benzene.

From Introduction: "Analyses of heat transfer for liquid metals flowing turbulently in smooth tubes (low Pradtl numbers) are given in reference 1 and 2. The predicted heat-transfer coefficients from these analyses are considerably higher than those determined in the experimental heat-transfer investigations for mercury and lead bismuth given in references 2 to 4. If the analytical and experimental results for flow of gases are compared at low Peclet numbers, they are also found to be in disagreement (references 5 and 6)."

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Physical data are presented for transverse CSF samples with capsule exposures of 568, 1049, and 1617 MD/CT. The higher exposures indicate a sharper damage gradient toward the front of the pile. Additional casings of various types of graphite were loaded into test holes during this month. Average values of the thermal conductivity and electrical resistivity for several types of virgin graphites are presented. Data of this nature will be a regular portion of this report henceforth. Process tube channel 2677-H was mined and traversed for bore diameter. Although several of the tube block junctions were obscured, the channel was quite uniform. Examination of all previously mined graphite powder samples for aluminum oxide corrosion product has been completed and the results are reported.

Control requirements were determined from calculated engine performance maps for a fixed-geometry ram jet of a configuration suitable for strategic supersonic missile propulsion. Several control schemes for attaining desired engine performance and for stabilizing missile flight velocity during cruise are presented. The advantages and disadvantages of each system are discussed.

"Paper presents a practical method for computing the approximate values of the normal component of the induced velocity at points in the flow field of a lifting rotor. Tables and graphs of the relative magnitudes of the normal component of the induced velocity are given for selected points in the longitudinal plane of symmetry of the rotor and on the lateral rotor axis. A method is also presented for utilizing the tables and graphs to determine the interference induced velocities arising from the second rotor of a tandem or side-by-side-rotor helicopter and the induced flow angle at a horizontal tail plane" (p. 1).