"Dust and gas masks and respirators have been an effective method under certain environmental conditions to reduce the inhalation of toxic aerosols. Under many conditions, however, their efficacy has been seriously questioned. It is the purpose of this study to evaluation over-all respirator performance on fine aerosols and to develop equipment whereby a greater degree of respiratory protection may be assured with reliability for highly toxic atmospheres."

The objective of the study which is being carried out under contract AT(30-1)-2477 is the exploration of all aspects of research in water resources and supply to determine the potential for using radioisotope technology in this research. Problem areas in the application of tracers in this research are being investigated through the evaluation of past experimentation with radioisotopic techniques and through discussions with those who are active in this work. A series of suggestions relating to these techniques will de drawn up to indicate which techniques should be developed further in order that more extensive applications may be found for them.

Work on the preparation of graphite spheres containing thorium oxide for use as breeder elements in the Pebble Bed Reactor-Steam Power Plant is described. Graphite spheres of varying density were infiltrated with thorium nitrate solutions, followed by denitration to thorium oxide.

"We want to point out that there is a possible method for determining the anomalous magnetic moment of the Λ from the observation of metastable states of hyperframents. There are two possible sources for the apparent difference of binding energies of a hyperfragment. One of these comes from the difference of Q values due to the decay into an excited and ground states of the residual nucleus. The other possibility will arise if there exists a metastable state of the decaying hyperfragment."

The spectrum of the mono-energetic neutron transport operator for a homogeneous sphere where the neutrons are scattered with spherical symmetry in the laboratory system is considered.

An approximate Boltzmann equation, known as the single relaxation model is studied here. This equation is linearized and the fundamental solution is considered. Following N. Grad, the solution, asymptotic in small values of the ratio of mean-free-path to distance from the origin, is sought. It can be shown that the fundamental solution itself gives the asymptotic description of the flow field past an object. This solution gives the asymptotic description when the distance from the origin is much greater than either the mean-free-path or the body size. This is true independently of the Knudsen number.

Absolute (p,n) cross sections have been measured for Ti47, V51, Cr52, Co59, and Cu63 at energies between 4 and 6.5 Mov. These data plus earlier measurements of the cross section for inelastic proton scattering have been used to estimate total proton absorption cross sections for V51 and Co59. An optical model calculation using parameters giving a good fit to elastic scattering measurements predicts an absorption cross section in good agreement with the measurements for Co59. For V51, some sets of parameters gave good agreement with the measured absorption cross section, but the fit to the elastic scattering data was only fair.