Abstract: "The purpose of this investigation is to determine the extent to which zirconium and zirconium alloys exhibit delayed failure (static fatigue) as caused by a combination of absorbed hydrogen and applied stress. Both notched and unnotched specimens of unalloyed zirconium and Zircaloy-2 have been hydrogenated to 200 ppm by means of a modified Sieverts apparatus; specimens were evaluated at room temperature. Thus far, no time-dependent fracture has been observed which can be attributed to the delayed failure phenomenon; it appears that these materials are relatively insensitive to static fatigue. The effects of grain size, temperature, cold deformation, and superheated water and steam corrosion on susceptibility to delayed failure are being determined."

The following report is the third Quarterly Report in a series whose investigative purpose is to determine the extent to which zirconium and zirconium alloys exhibit delayed failure as caused by a combination of absorbed hydrogen and applied stress.

The following report summarizes an investigation made to determine the extent to which zirconium and zirconium alloys exhibit delayed failure as caused by a combination of absorbed hydrogen and applied stress during the period September 15, 1961, to September 14, 1962.

The following report provides information on an aerosol generator fit to produce fine particles by a vaporization-condensation technique. Included is a diagram of the essential components of the generator.

Abstract: "Experimental investigation of aerosol particle capture by evaporating and condensing water drops has shown that capture is a function of the rate of water drop growth and aerosol particle diameter. Capture was found to be proportional to the rate of water vapor condensation and inversely proportional to aerosol particle diameter. The influence of water vapor gradient and particle size on aerosol particle capture during evaporation is insignificant. The experimental results are explained on the basis of particle penetration through the boundary layer of a water drop. An analysis of previous research on radioactivity of dry particulate matter in an urban atmosphere is included."

A report which provides information about the McBrain-Bakr sorption balance that is used to study vapor phase sorption of iodine by active carbons and to calculate the surface areas of the carbons.

From introduction: "This study is concerned with the basic variables that affect the electrostatic classification of heterogeneous aerosols in the submicron range, especially below 0.1 micron. The variables of interest are particle size, concentration, composition, dielectric constant, shape, and initial charge as they relate to rate of charging and therefore to the point of deposition in the classifier."

Introduction: "This program is a study of the basic variables that affects electrostatic classification of heterogeneous aerosols of submicron size, especially below 0.1 micron. The variables of concern are particle size, concentration, composition, shape, and initial charge. During this period optimum charger design was studied. The results will serve as a basis for a systematic study of particle charging. A number of improvements were incorporated into the classifier flow system and electrical circuits. The technique for photographing deposits in the electron microscope was also improved, and sample photographs are included."

Introduction: "This program is a study of the basic variables that affect electrostatic classifications of heterogeneous aerosols of submicron size, especially below 0.1 micron. The variables of interest are particle size, concentration, composition, shape, an initial charge. During this period emphasis was placed on studying and controlling initial charge. A new technique was developed for collecting light and electron microscope samples. Further improvements of the charging device were studied."

Abstract: "This program is a study of the basic variables that affect electrostatic classification of heterogeneous aerosols of submicron size,especially below 0.1[mu]. The variables of interest are particle size, concentration, composition, shape, and initial charge. During this period research was concerned with classifying particles as small as 0.01[mu]. This research included work on an aerosol generator for monodispersed 0.015-[mu] gold particles. The performance of the charger was further improved by studying its basic electrical characteristics. Tests with the electrostatic classifier showed very clearly the interference due to the stabilizer material associated with polystyrene latex suspensions. These suspensions are used to produce monodispersed aerosols for calibration."

From abstract: "This program was a study of the basic variables that affect electrostatic classification of heterogeneous aerosols of submicron size, especially below 0.1 [mu]."

Introduction: "This project is a study of eletrostatic classification of submicron aerosols with emphasis on particles below 0.1[mu]. Previous work has shown that classification of particles between 0.1 to 1.0[mu] is feasible by this process. Further improvements along this line include the elimination of interference from initial aerosol charge and increase in sampling rate. The effect of heavy deposits on collection have to be established. More information is desired on the charging regime below 0.1[mu]. Also the overlap of the smallest particles with the larger ones has to be eliminated. It is also of interest to study the possibility of measuring the current due to the precipitating particles. This would make it possible to automate the device. During this period project work was initiated again. There was some delay in finalizing the contract and the laboratory work was not started until early in March."

The following report focuses on the study of electrostatic classification of submicron aerosols, with emphasis on particles below 0.1 micron. During the period this work was concerned with detailed studies of the ARF charger, the Whitby ionizer used as a charger or neutralizer, and the high-volume classifier.

Introduction: "This project is a study of electrostatic classification of submicron aerosols, with emphasis on particles smaller than 0.1 micron. The overlap of the smallest particles with the larger ones is of principal concern. Also, a faster sampling rate is desired, i.e., heavier deposits in a shorter time are necessary. During the period covered by this report, work was concerned with studies of charging by corona and diffusion, neutralization of initial charge, and classification of various types if aerosols."

Introduction: "This study is concerned with the classification of submicron aerosols by electrostatic means. The controlled charging of the particles without undue aerosol losses is of principal interest. We are investigating means of eliminating the interference due to the deposition of small and large particles in the same area. The sampler is to be developed to classify atmospheric dust particles at a rate approaching 1 cfm. During the period covered by this report, work was concerned with the charger and with bringing the high-volume classifier into routing operation. Further tests were made on the classification of atmospheric dust."

Introduction: "One of the major objectives of this study is to develop a routine charger that has no aerosol losses. Also, the interference due to deposition of small and large particles in the same area must be overcome. During this period efforts were concentrated on the former problem, which is the key to practical application of this device."

From abstract: "This project was a study of electrostatic classification of submicron aerosols. Classification of particles as small as 0.006-[mu]-diameter was shown to be feasible, and good classification of atmospheric dust was achieved. However, a practical solution to the problem of overlapping between particles larger and smaller than 0.1 [mu], the point of minimum electric mobility, was not found."

From abstract: "This report describes and evaluates the variables affecting contamination of precise devices...In the present report these variables are discussed in more detail and the basis for their inclusion in the listing are given. The relative importance of the several parameters will be discussed in another report."

The following quarterly report covers the period from May 16 to August 15, 1962. This report summarizes the progress being made on the study of the saturation and recovery of the hole which can be burned into the magnetic resonance band associated with the F-center in KCl.

The following quarterly progress report covers the period of August 15 to November 15, 1962. It summarizes three activities of the group. The first part is the optical study of the absorption band associated with the F-center in RbCl. The second part discusses some elementary calculations of the spin-lattice relaxation times, the primary purpose of this step is to indicate the nature of the theoretical problem faced and show the large gap between the value calculated theoretically and measured experimentally. The last section includes more data on the shape and recovery of the hole in a EPR band associated with the F-center in KCl.

The following quarterly progress report covers the period from November 16, 1962 to February 15, 1963. This report summarizes three activities that study the ratio of the maximum absorption of the K band to the maximum absorption of the F band has been made in additively colored and [gamma]-irradiated rubidium chloride.

The following quarterly report covers the period during February 16 to May 15, 1963. This report is divided into sections covering the separate activities during this period, studying the thermal behavior of the F-center in RbCl.

A report which intends to make a compilation of neutron capture gamma ray spectra of naturally occurring elements, covering both the low and the high energy spectral region, using NaI(TI) scintillation detectors.

A report which describes the how the low energy neutron capture gamma ray spectra has been obtained for inclusion in the atlas along with many ores. In addition to gaining this spectra, tests were conducted with the 5'' by 4'' NaI(TI) crystal in the present detector system.