This monthly report details Physics Department 100 Area technical activities for the month of April 1947.

"Performance characteristics of the turbine in the 19B-8 jet propulsion engine were determined from an investigation of the complete engine in the Cleveland altitude wind tunnel. The investigation covered a range of simulated altitudes from 5000 to 30,000 feet and flight Mach numbers from 0.05 to 0.46 for various tail-cone positions over the entire operable range of engine speeds. The characteristics of the turbine are presented as functions of the total-pressure ratio across the turbine and the turbine speed and the gas flow corrected to NACA standard atmospheric conditions at sea level" (p. 1).

Report presenting an analytical investigation to determine primarily the reduction in cooling-air requirement and the increase in effective gas temperature for the same quantity of cooling air resulting from the use of an insert in the cooling-air passage of a hollow air-cooled turbine blade.

Empirical design curves are presented for the critical stress of thin-wall cylinders loaded in axial compression. These curves are plotted in terms of the nondimensional parameters of small-deflection theory and are compared with theoretical curves derived for the buckling of cylinders with simply supported and clamped edges. An empirical equation is given for the buckling of cylinders having a length-radius ratio greater than about 0.75.

"A solution is presented for the coupled modes and frequencies of swept wings mounted on a fuselage. The energy method is used in conjunction with power series to obtain the characteristic equations for both symmetrical and asymmetrical vibration. A numerical example which is susceptible to exact solution is presented, and the results for the exact solution and the solution presented in this paper show excellent agreement" (p. 1).

Report presenting the results of flight testing to determine the zero-lift drag of an NACA 65-009 airfoil at a specified aspect ratio. The results are compared to previous testing of unswept and swept-back arrangements. The swept-forward and swept-back airfoils were found to produce lower values of zero-drag lift than the unswept airfoil.

In order to further understand the nature of changes which occur in the fingers of persons occupationally exposed to radiation a series of experiments were performed on human subjects generally using x-rays at 130 KV potential, 20 ma and at a distance of 10 cm. Doses ranged from 200-600 r. Fourteen subjects were patients being treated by x-rays or radium for other purposes. The other subject was a staff member who occasionally prepared radium plaques containing 130 mgm of radium. Counts were made of the number of vessels in the terminal row of a measured area of the nail fold. In no case was there any detectable change in the nail fold area within 15 minutes of treatment. Observations were continued for up to 56 days and changes observed included hyperemia, pigmentation, erythemia, and some transitory changes in vascular structure of the affected area. A recommendation for continued studies is made.

"An investigation was conducted on a multicylinder aircraft engine on a dynamometer stand to determine the effect of induction-system icing on engine operating characteristics and to compare the results with those of a previous laboratory investigation in which only the carburetor and the engine-stage supercharger assembly from the engine were used. The experiments were conducted at simulated glide power, low cruise power, and normal rated power through a range of humidity ratios and air temperatures at approximately sea-level pressure. Induction-system icing was found to occur within approximately the same limits as those established by the previous laboratory investigation after making suitable allowances for the difference in fuel volatility and throttle angles" (p. 1).

Abstract: "The Calutron has been successfully employed to separate the stable isotopes of twenty-one elements. The standard Beta M-2 unit modified to handle charge materials of various temperature ranges has proven adequate for a majority of separations. The problem of K life has received considerable attention but is still to be solved. Other operational problems are similar in most respects to those of uranium. The E design has, of necessity, varied greatly from the "Beta Gloria" type. A desire to keep construction simple, yet adequate for efficient collection and readily adaptable for use with many elements, has dictated the trend in E design. Water cooling on the receiver pockets was necessary with many of the elements separated. The chemical purification of the separated samples, although following a general pattern, varies with the type of pockets used and the element collected."

This technical progress letter contains reports from six Technical Department divisions at the Hanford Engineer Works for February 9, through February 15, 1947. The six reporting divisions are: 100 Areas, 300 Area, 200 Areas, Chemical Development, Laboratories, and Statistical Studies.

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.

From Summary: "The results of flight tests to determine flying qualities of a Chance Vought F4U-4 airplane are presented and discussed herein. In addition to comprehensive measurements at low altitude (about 8000 ft), tests of limited scope were made at high altitude (about 25,000 ft)."

Report presenting testing conducted on two airfoils from a series of rectangular-plan-form airfoils of aspect ratios 7.6 and 5.1 and with NACA 65-006, 65-009, and 65-012 sections using the free-fall method. Results regarding the time histories, ground-velocity data, airfoil drag measurements, and drag coefficients are provided.

"A preliminary investigation was made to determine the effects of gamma radiation on the age-hardening rate of an aluminum-copper alloy at temperatures of 32 and 70 degrees Fahrenheit. The gamma radiation from a 100-milligram radium source appeared to have no significant effect on the age-hardening rate of the alloy. A metallographic examination of the test specimens showed no microstructural changes that could be attributed to gamma radiation" (p. 1).

Abstract: Solid ferric chloride reacts with solid uranium tetrachloride to form a complex iron-uranium chloride compound at approximately 263°C. The vapor pressure of this compound is nearer to that of uranium tetrachloride than to the vapor pressure of ferric chloride.

"This paper develops a new method for determining the buckling stresses of cylindrical shells under various loading conditions. In part I, the equation for the equilibrium of cylindrical shells introduced by Donnell in NACA report no. 479 to find the critical stresses of cylinders in torsion is applied to find critical stresses for cylinders with simply supported edges under other loading conditions. In part II, a modified form of Donnell's equation for the equilibrium of thin cylindrical shells is derived which is equivalent to Donnell's equation but has certain advantages in physical interpretation and in ease of solution, particularly in the case of shells having clamped edges" (p. 285).

"Report of the Survey of Los Alamos and Pueblo Canyon for radioactive contamination and radioassay tests run on sewer water samples and water and soil samples taken from Los Alamos and Pueblo Canyons." The objective of this report was to determine the extent and sources of radioactive contamination in the areas studied.

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Price Daniel, regarding a legal question submitted for clarification: Authority of the Highway Department to require the surrender of driver's license; sufficiency of demand for such license.

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Price Daniel, regarding a legal question submitted for clarification: Authority of the Commissioners' Court to determine sheriff's bond and pay premiums on official bonds of sheriff's deputies in salary counties.

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Price Daniel, regarding a legal question submitted for clarification: National forest receipts, prorating of under Article 2351b-4, V.C.S.

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Price Daniel, regarding a legal question submitted for clarification: The matter of jurisdiction over felony cases of the District Courts of Bexar County.

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Price Daniel, regarding a legal question submitted for clarification: Under Sec. 2, Article 4344, R.C.S., may Comptroller change rule regarding assessment of poll tax by County Tax Collector?

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Price Daniel, regarding a legal question submitted for clarification: Whether or not there is a vacancy in the office of Justice of the Peace of Precinct 2, Fannin County, under the facts submitted.

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Price Daniel, regarding a legal question submitted for clarification: Whether S.B. Nos. 183 and 213, authorizing cooperative rate making practices, exempt such activities from the antitrust laws of Texas.