Summary: The use of dimensionless-parameter frequency response diagrams to determine accuracies of lumped-parameter approximations is demonstrated by two examples: calculation of the heat flux at the surface of a semi-infinite solid due to temperature fluctuations of an adjacent fluid; and the response of a counterflow heat exchanger to inlet fluid temperature perturbations. Dimensionless system parameters make it possible to use general-purpose plots to find the error in particular approximations as a function of the frequency of perturbation. Such plots are directly applicable to control-system stability problems, where the highest frequency of interest is usually apparent.

The purpose of this report is to present a method of impregnating beryllium oxide with uranium and to describe the properties of beryllium oxide and of commercial beryllium oxide ceramics.

Abstract: "The age-diffusion is adequate to describe the neutron behavior of a very large class of nonthermal reactors (all except those whose dimensions are comparable to the neutron mean free path). Thus, a convenient means of obtaining an accurate solution to this equation is very useful for general reactor calculations. Methods for reducing the age-diffusion equation to a finite set of coupled ordinary differential equations, called multigroup equations, are described. The relative merits of several alternate schemes are discussed. The multigroup equations may be solved by iterative procedures based on an assumed spatial distribution of the fission source neutrons. In practice the initially assumed source shape is accurate enough so that additional iterations are unnecessary. Analytical and numerical methods for solving the multigroup equations with the assumed source are discussed. The adjoint equations are also reduced to multigroup form, and examples of the adjoint function in obtaining improved reactivity values are given."

"The purpose of this memo is to set down a derivation and numerical technique for a method that can be used for criticality calculations on bare reactors containing hydrogen together with another moderator such as BeO. The method and notation are that of G. Goertzel (NDA)-1, and D. Selengut (NEPA). In the interest of the computers, the numerical technique, associated notation, and calculation form are modeled after that currently used by the ANP Physics Group for BeO moderated reactors."

An airborne radiometric survey of the Denver Basin made during the moths of May, June, and July.

Abstract: The purpose of this report is to outline the work done at the Radiation Laboratory toward the development of a magnetic field measuring device using the phenomenon of nuclear resonance. While the work described here is far from complete, it has served to indicate the limitations of the method as well as some of its possibilities. For reasons which will become apparent, the project is being discontinued. It is hoped that this report will serve as a starting point should the work be continued at some later time and that some of the mistakes already made need not be repeated.