Physics Commons^™

A New Determination Of The Homogeneous Nucleation Rate Of Water In Helium, Edward Francis Allard

Doctoral Dissertations

"The object of this investigation is to apply the best known cloud chamber techniques to the study of condensation phenomena, directed mainly toward the development of a precise method for the determination of homogeneous nucleation rates. A secondary object is to investigate the properties of re-evaporation nuclei so that adequate precautions may be taken to eliminate their detrimental effect in the homogeneous nucleation experiments"--Statement of Problem, page 10.

On The Kirkwood Superposition Approximation, Russell V. Cochran Jr.

Doctoral Dissertations

"When the Kirkwood superposition approximation for the triplet distribution function is used in the Born-Green equation for the pair distribution function of a liquid, the fourth virial coefficient is given incorrectly. In view of this, two suggestions for improving the approximation have been investigated. A suggestion, due to G.H.A. Cole, that better results could be obtained by using a second-order integro-differential equation of the Born-Green type with the superposition approximation used for both the triplet and quadruplet distribution functions has been investigated, and results for a hard-sphere model show that this method gives considerably less reliable results than those obtained …

Studies Of An Electrical Method For Generating Ultrasonic Waves, Yung-Yien Huang

Masters Theses

“Ultrasonic waves have proved very valuable in the observation of both the velocity and the absorption coefficient of sound in various media. From the velocity measurements of ultrasonic waves in metals, it is possible to obtain elastic constants, such as the compressibility, and the specific heat. Also, the observed attenuation depends greatly on the type and structure of the material. One of the widely used methods for investigation of the internal losses in solid state physics is the pulse-echo technique. This method is being used almost exclusively in internal friction investigation"--Introduction, page 1.

Determination Of The Fast Flux Of U.M.R. Reactor, Dave Vibhakar Ratilal

Masters Theses

"Measurements of fast flux of University of Missouri at Rolla, Reactor have been made using: (n,p) reactions in Mg²⁷ and Ni⁵⁸ and (n,α) reactions in Al²⁷. The effective activation cross sections at respective threshold energies for various foils have been obtained from AERE and AECL reports and from literature published by various investigators. A RIDL 400 channel analyzer was used for counting"--Abstract, page 1.

Aging Of The Dielectric Properties Of Some Perovskite Ceramics, Hector Troche-Maldonado

Masters Theses

"The effect of aging upon the dielectric constant and the dissipation factor were investigated for a number of lead titanate zirconate ceramics of varying composition. The ceramics investigated have a perovskite type structure. The materials chosen all have tetragonal symmetry at room temperature but are close in composition to materials of rhombohedral symmetry.

Empirical relations were determined for each specimen giving the rate of aging of the dielectric constant (K) and loss factor in terms of the frequency (f) and the elapsed time (t). The range of frequency was l kcps to l mcps; the range of elapsed time was …

An Investigation Of The Sensitized Fluorescence Of The Mercury-Sodium And The Cesium-Rubidium Systems., Joseph Edward Hueser

Masters Theses

"The experimental apparatus and techniques used for the study of sensitized fluorescence are discussed. In this study both glass and metal absorption cells were employed. Included also is a discussion of the transitions which 11 occur in the mercury-sodium and the cesium-rubidium systems, which were the two systems investigated. Both photographic and photometric techniques were used as means of detecting the sensitized fluorescence. The actual experimental apparatus used are discussed together with conclusions to be drawn and recommendations to be made from the individual experiments. The purpose of the experiments was to better understand the energy exchange processes in a …

Construction And Test Of Equipment For Use In Ultrasonic Pulse Echo Studies., Charles Joseph Reinheimer

Masters Theses

"An ultrasonic pulse generator was constructed with a variable pulse width ranging from 4 microseconds to 10 milliseconds and a repetition period varying from 15 milliseconds to 5 seconds. The oscillator had an almost continuous range from 500 kilocycles to 18 megacycles per second.

Its applicability in studies of internal friction of metals was demonstrated with a single crystal aluminum sample"-- Abstract, p. vi

A Study Of The Effect Of The Crystal Orientation On The Internal Friction Of Magnesium Single Crystals., Robert Ray Nothdurft

Masters Theses

"The method of growing, etching, and cutting magnesium single crystals is described in some detail. Ten single crystals of magnesium of different orientations were prepared and studied. The internal friction and relative Young’s modulus were measured for each specimen as a function of applied stress on a quartz composite oscillator. The effect of the orientation on the strain amplitude independent decrement, the strain amplitude dependent decrement and the ratio of the strain amplitude dependent decrement to the relative Young's modulus is compared to the theory of the pinned dislocation model of Granato and Lücke"--Abstract, p. ii