Physical Sciences and Mathematics Commons^™

The Kinetics Of Phase Transitions In Solid Cyclohexanol And Related Plastic Crystals., William Thomas Griffith

Physics & Astronomy ETDs

The phase relations and the kinetics of phase transitions in the solid -forms of cyclohexanol, cyclohexanone, chlorocyclohexane, bromocyclohexane, and cyclopentanol have been investigated. Cyclohexanol has been studied the most thoroughly; the other compounds have been considered largely for purposes of comparison with cyclohexanol. The primary methods of investigation have been the measurement of dielectric properties and visual observations. The transitions in cyclohexanol have also been followed photographically in order to measure the growth velocities of the phase interfaces.

A Study Of The Backscatter Of Light From A Single Water Droplet, Theodore Stauffer Fahlen

Physics & Astronomy ETDs

The backscattered light from a single water drop is studied theoretically and experimentally for drop diameters of about one millimeter. G. Mie gave the exact mathematical solution to the problem of an infinite, plane, monochromatic, electromagnetic wave scattered from a perfect sphere of any radius and index of refraction in 1908. The results of this theory are applied to drops of size parameter (defined as the ratio of the drop circumference to the wavelength of the incident light) near 3000; this corresponds to a drop diameter of about one millimeter. Theoretically, it is shown that the backscattered light originates from …

Rocket Probe Measurement Of Electron Energy Spectra In The Earth's Radiation Belts, Donald Stuart Robb

Physics & Astronomy ETDs

No abstract provided.

Nuclear Quadrupole Relaxation., Derwin F. Brown

Physics & Astronomy ETDs

A nucleus with an asymmetric charge distribution (an asymmetric arrangement of protons) exhibits a quadrupole moment which interacts with the gradient of the electric field of the surrounding electrons. The interaction energy is a function of the angle between the nuclear spin axis and the axis of the surrounding electric field. The nucleus processes about the electric field axis in quantized energy states. These quantized energy states correspond to a hyperfine splitting simi­lar to the hyperfine structure of the magnetic dipole-dipole interaction between the nucleus and the electrons. The application of an external electric field, oscillating at the processional frequency …

An Introduction To The Fundamentals Of Radiation Transport Theory., William A. Proctor

Physics & Astronomy ETDs

I first became interested in radiation transport theory when, in August 1966, I was given primary responsibility for a large computer program which serves as a tool for solving high temperature, time dependent, radiation-hydrodynamics problems. Inquiries as to where to start learning about this subject invariably resulted in my being directed to the two books by Chandrasekhar (1957 and 1960) and the book by Kourganoff (1963). From the beginning of my study of these expositions, I found it rather curious that a theory which treated the radiation field as continuously distributed in space was formulated in a manner which appeared …

Measurements Of Solar X-Ray Emission From The Ions Carbon Vi And Nitrogen Vii, Winifred Doyle Evans

Physics & Astronomy ETDs

Studies of the solar spectrum in the extreme ultraviolet and x-ray region have been possible since sounding rockets and satellites have been available to carry instruments above the earth's atmosphere. Progress was slow at first, but techniques have improved rapidly in recent years and a considerable body of experimental data has been accumulated since the first rocket flights in the late 1940’s.

Analysis Of Particle Counting Rate Variations Observed On Satellite Oso-B2, Esther Y. Ma

Physics & Astronomy ETDs

The ommidirectional cosmic ray fluxes at an altitude of 300 miles and within ± 34 degrees latitude were studied using two Cerenkov counters and a scintillation counter aboard the 0S0-82 Satellite. The fluxes were found to depend strongly on the geomagnetic field with the trapped particles in the South Atlantic Radiation Anomaly being directional in some locations.

Step-Wise Variation Of Spectrometer Quench Rates For Nuclear Quadrupole Resonance Measurements, Curtis M. Wise

Physics & Astronomy ETDs

In nuclear quadrupole resonance (NQR) it is desirable to better examine the magnitude of the resonance signals. This thesis describes the construction and testing of spectrometer control circuits which enable one to better examine a single resonance signal to the near exclusion of extraneous resonance side band responses and circuit noise in the NQR detection apparatus. Added to the basic spectrometer circuit is a step-wise varying quench rate control. For each adjustment of this control other control units are activated to keep the chosen NQR signal fixed in position and in magnitude within the spectrometer's span of detected radio frequencies. …

²⁰⁷Pb (N, N') ²⁰⁷Pbm And ²⁰⁸Pb (N, 2n) ²⁰⁷Pbm Cross Sections, Edward Raymond Shunk

Physics & Astronomy ETDs

The cross sections for the production of the ²⁰⁷Pb^m state from ²⁰⁷Pb(n, n') and ²⁰⁸Pb(n, 2n) have been measured from the threshold through 14 MeV by observing the 1 .064 MeV gamma ray in the decay of ²⁰⁷Pb^m (T _½ = 0.818 ± 0.004 sec) with a 3 in. x 3 in. NaI (T1) detector. Separated lead isotopes were irradiated for 4 sec and pneumatically transported to the detector. A 400-channel analyzer a used a time analyzer to record counts from neutron monitor during the irradiation and from the detector after the irradiation. These …

The 233u Fission And Capture Cross Sections And Their Analysis At Low Engines, Delmar W. Bergen

Physics & Astronomy ETDs

The ²³³U fission and capture cross sections were measured using a nuclear-device neutron source and time-­of-flight techniques. Cross section data are presented from 20 to 10⁶ eV for fission and from 20 to 63 eV for fission + capture. The resonance region (20 eV to 63 eV) was fitted with both a single level function consisting of a sum of Breit-Wigner levels and the Reich and Moore multilevel function based on R matrix theory. The resulting resonance parameters are listed and discussed. In order to establish the validity of the resonance parameters derived from the multilevel fit, a …

Geophysical Institute Annual Report 1966-67, University Of Alaska Fairbanks. Geophysical Institute

GI Reports

The 1966–67 Geophysical Institute Annual Report presents an overview of the year’s scientific research achievements across the Institute’s disciplines, alongside operational summaries covering finances, administrative changes, and other key activities.

Equation Of State Of Sodium Chloride, Daniel L. Decker

Faculty Publications

Because of many requests, I wish to publish the following numerical table of results for the equation of state of NaCl as calculated in an earlier paper1 along with a few comments on various proposed equations for NaCl. Table I gives the pressure in kilobars at the corresponding values of t.a/ao and temperature in the appropriate row and column. The parameter t.a/ao is the fractional compression of the lattice parameter where the standard value ao is the appropriate lattice parameter at zero pressure and 25°C. The increments between the values given in the table were chosen such that one can …

Model Of Electron Correlation In Solids, Everett G. Larson, Walter R. Thorson

Faculty Publications

The usual Hartree-Fock model (energy-band theory) does not always give an adequate description of electronic structure in a solid, because it ignores the effects of electron correlation. It was shown first by Wigner that such a situation always develops in an electron ''gas'' at sufficiently low density; a solid structure described by ''resonance'' of Heitler-London pair bonds between electrons localized on neighboring atoms is then a good model of the system.The transition from a Bloch-type state to such a highly correlated state as a function of electron density (lattice parameter) is a problem of considerable interest for the theory of …

Surface-Wave Phenomena At A Water-Air Interface., Benjamin W. Woodward

Physics & Astronomy ETDs

The existence of a surface wave accompanying total internal reflection of light in a dielectric material was derived classically to satisfy boundary conditions at the surface. Using this fact, in 1929 J. Picht proposed a mechanism for total reflection that led to the conclusion that a finite ray of light would undergo a small translation at the boundary, parallel to the boundary and in the plane of incidence. In 1943 Goos and Hänchen made quantitative measurements of this translation or shift. Subsequently many theories have been advanced analyzing this phenomenon in detail, but as of this writing no other experimental …

Pressure Calibration To 100 Kbar Based On The Compression Of Nacl, R. N. Jeffrey, J. Dean Barnett, H. B. Vanfleet, H. Tracy Hall

Faculty Publications

An independent determination has been made of the transformation pressures assigned to the high-pressure transformations in Ba and Bi which are generally used for calibration points. The metals were imbedded in NaCl, and the transitions were detected by the resistance change of the metal while the NaCl lattice parameter was simultaneously measured by x-ray diffraction. The NaCl compression values determined at the fixed points were related to pressure by reference to the semiempirical compression curve of Decker. The Ba I-II and Bi III-V transformations at room temperature were assigned thermodynamic equilibrium values of 53.3 ±1.2 kbar and 73.8 ±1.3 kbar, …

Geometrical Representations Of Relativistic Motion, Jeffrey H. Robbins

Physics & Astronomy ETDs

This investigation begins with the development of a transformation or mapping in velocity space of such a character that velocities are mapped into a quantity that adds linearly, while velocities add non-linearly according to the Einstein Law of Addition, and has no upper limit to its magnitude, i.e., when the speed of an object approaches that of light in a vacuum, this quantity becomes infinitely large. Kinematic relationships, in Newtonian form, for a particle undergoing acceleration, are developed in a frame of reference that remains attached to the particle using the new variable (W). It is found that relativistic energy …

Angular Distribution Of Neutrons In Atmosphere Produced By Protons, Donald Stuart

Physics & Astronomy ETDs

In connection with the balloon flown directional neutron detector experiments in progress, the following theoretical problem presented itself. Find the angular distribution of neutrons incident upon a detector. This is investigated under varying conditions using a computor program prepared for this problem. Two models for the problem are considered in this paper. In the first model we choose the simplest conditions that approximate a possible physical situation. This consisted of considering that the system was completely isotropic. For certain altitudes this gave very good results as can be seen by the curves. Then modifications to the theory are discussed. This …

Coulomb Excitation Of The Ytterbium Isotopes., John M. Palms

Physics & Astronomy ETDs

Coulomb excitation studies have been performed on the ytterbium isotopes 171, 172, 173, 174, and 176 using oxygen ions having energies up to 55 MeV. Resulting de-excitation gamma rays have been observed in particle coincidence with a NaI(Tl) detector and as single spectra with a Ge(Li) detector. The ground state rotational bands of the Yb171 and Yb173 isotopes have been excited to the 13/2- level. The 13/2- and 11/2-levels of both nuclei have not been reported before. In addition to the transitions from the ground state band, gamma rays were observed from Yb171 and Yb173 coming from other bands. A …

Investigation Of Propagation Of Light Through Gases And Air Structures Treated As Wave Guides., Richard W. Christiansen

Physics & Astronomy ETDs

The equations defining the propagation of electromagnetic radiation down cylindrical dielectric wave guides are developed. A Helium-Neon laser is used to illuminate several different cylindrical wave guides. The propagation nodes are recorded on photographic plates. Using the field equations, the electric field on a transverse plane is plotted and used to explain some HE_im modes observed. The patterns recorded on the photographic plates are described and discussed in terms of the propagation modes.

Measurements Of Continuous X-Ray Spectra With A Scintillation Spectrometer, Ellery Strom

Physics & Astronomy ETDs

Scintillation spectrometer measurements were made of the x-ray spectra produced by a constant-potential x-ray unit operating at 100, 150, 200, 250, and 300 kV. An attempt was made to measure the absolute intensity as well as the spectral distribution. In order to reduce the counting rate to a measureable level, it was necessary to place the thallium-activated sodium-iodide detector 50 meters from the target. Since the air attenuation was quite large, measurements were made both in air and in helium. In order to contain the helium, an Orangeburg pipe was employed, and its effect on the spectra was determined by …

Some Factors Which Influence The Intensity And Resolution Of Beams In Neutron Diffractometers, Robert G. Wenzel

Physics & Astronomy ETDs

The problems of the intensity and resolution of a neutron diffractometer are considered, both for elastic and inelastic scattering studies. The considerations are applied to the choice of parameters for a new diffractometer. First to be taken up is the manner in which the intensity of a diffraction monochromating system varies with its collimators, which affects both kinds of studies. A model is chosen and used to derive an expression tor the intensity. The expression is checked experimentally and found not be be valid over the range of collimators available. However, over a smaller range, such as those collimators which …

High Frequency Scattering From A Schroedinger Square Well, Robert R. Thede

Physics & Astronomy ETDs

Many observations have been made of the enhanced back scattering of light waves from water droplets. This phenomenon, commonly referred to as the glory, is inexplicable in terms of ray optics. Calculations based upon the Mie series solution to the scattering of an electromagnetic plane wave from a dielectric sphere suggest that this pronounced scattering is due to surface waves which travel around the sphere and are emitted in phase preferentially in the forward and backward direction. These results have also been verified experimentally by examining the backscattered light from a water droplet.

X-Ray Diffraction Studies On Tin To 100 Kilobars, J. Dean Barnett, Vern E. Bean, H. Tracy Hall

Faculty Publications

The high-pressure equilibrium phase diagram of tin is investigated, and the crystal structure of Sn II at 98 kbar and 25degrees C is shown to be body-centered tetragonal with a=3.70 Angstroms, c=3.37 Angstroms, c/a=0.91, and with two atoms per unit cell. The linear compressibility of white tin is given at 25degrees C up to the high-pressure transformation at 92 kbar, and the latent heat of the transformation is measured as 225 cal/g-atom.

The Interaction Of 22-Mev He³ Particles With Fe⁵⁶, ⁵⁸ And Ni ⁵⁸, Edward R. Flynn

Physics & Astronomy ETDs

A systematic study is made of the interaction of 22-MeV He³ ions with several medium-weight nuclei. The central purpose of this study is to compare the interactions induced by this strongly absorbed, spin-­one-half projectile to those induced by the more commonly used nuclear probes: neutrons, protons, and alpha particles. The target nuclei are restricted to three cases, Fe^56,58 and Ni⁵⁸, but the scope of the experimental studies is as extensive as the variety of experimental equipment available would allow. These studies then include the elastic and inelastic scattering as well as the neutron spectra in the …

Geophysical Institute Annual Report 1965-66, University Of Alaska Fairbanks. Geophysical Institute

GI Reports

The 1965–66 Geophysical Institute Annual Report presents an overview of the year’s scientific research achievements across the Institute’s disciplines, alongside operational summaries covering finances, administrative changes, and other key activities.

Charged Particle Fluxes In The South Atlantic Radiation Anomaly, Nicholas S. P. King

Physics & Astronomy ETDs

Data from a scintillator and two Cerenkov counters aboard the 0S0-B2 satellite are converted from counting rates to omnidirectional fluxes in the South Atlantic Radiation Anomaly. Isointensity contours are obtained for the anomaly with omnidirectional fluxes being of the order of 90 protons/cm2 -sec and 5 x 10 3 electrons/cm2 -sec. The South Atlantic Radiation Anomaly is postulated to include an electron dump into the earth's atmosphere due to the observed differences between the isointensity distributions for protons and electrons.

The Structure Of The Vibrational Relaxation Zone Of Shock Waves In Oxygen, Robert W. Lutz

Physics & Astronomy ETDs

The vibrational relaxation of pure oxygen has been studied in incident shock waves in the temperature range l000-3700° K. The re­laxation process was observed by measuring density gradients in the relaxation zone with the quantitative laser schlieren technique. The high sensitivity of this technique allowed determination of the relaxation time T, defined by the Bethe-Teller equation

= [ E - E ],

as a function of temperature and pressure in the relaxation zone. The variation in P the relaxation time at one atm, during th individual experiments, was found to agree with the over-all temperature dependence derived from the entire …

An Experimental Study Of The Back Scattering Of Coherent Light From Falling Water Drops., William Ogle

Physics & Astronomy ETDs

Introduction

The purpose of this study is to make a statistical investigation of the backscattering of light from freely falling water drops, and to determine if the surface wave is a significant contribution to the backscattered intensity from large drops.

An Experimental Study Of The Rate Of Evaporation Of Water Droplets., Pyung Syk Ro

Physics & Astronomy ETDs

The basic equation (Maxwell equation) for the evaporation rate of small droplets motionless relative to the ambient gas is verified by our experiment using an ultrasonic droplet suspension device. By using an ultrasonic device, a good approximation to the conditions of evaporation of free water droplets ranging from 0.4 mm to 2.0 mm in diameter is obtained.

Since it is expected that the back-scattering cross section of an incoherent light beam from a water drop is proportional to the square of the radius of the water drop, the possibility of measuring evaporation rates by using incoherent light is suggested. This …

A Theoretical Study Of Light Scattering From Water Droplets., Aaron J. Cox

Physics & Astronomy ETDs

No abstract provided.