Digital Commons Network^™

Simultaneous Movement Of Water And Herbicides In Unsaturated Soils, Ming-Shyong Yang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Since weed killers were developed in the early part of the decade beginning in 1940, herbicides have been increasing in use until they are now widely used to control weeds. The application of herbicides has thus become a regular agricultural and ecological practice.

Simultaneous Flow Of Heat And Water In Plant Tissue, Gaylon Sanford Campbell

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Although biological phenomena may be partially described in a general way without the use of mathematics and physics, the experimental results may be more meaningful if they are analyzed on the basis of physical and mathematical laws. The complexity of biological systems has made the application to them of mathematics and physics rather difficult, and only recently has much progress been made. Although it has yet been possible to describe only a few simple biological systems by actual equations, a great deal of qualitative information may be obtained by applying physics and mathematics. Russell (1960, p. 439) said

In principle …

Hyperfine Fields And Isomer Shifts In Magnetically Ordered Europium Compounds, H. H. Wickman, I. Nowik, J. H. Wernick, D. A. Shirley, Richard B. Frankel

Physics

The Mössbauer technique was employed to study hyperfine fields in several ordered divalent europium compounds at low temperatures. The intermetallics EuCu₂, EuAl₂, and EuAl₄ were ordered at helium temperatures and the observed fields and isomer shifts were 189(8) kOe, −0.88 cm∕sec; 278(8) kOe, −0.97 cm∕sec; and 290(8) kOe, −1.14 cm∕sec, respectively. Comparison of these results and previous measurements with EuO, EuS, and Eu metal indicates a possible correlation between isomer shift and internal field. With the exception of EuCu2 the internal fields increase with increasing magnitude of isomer shift. Interpretation of this trend with a …

Ferromagnetic Metals In High Magnetic Fields, A. J. Freeman, N. A. Blum, S. Foner, Richard B. Frankel, E. J. Mcniff, Jr.

Physics

High‐field susceptibility results are presented for Mössbauer measurements on iron at low temperatures in fields up to 135 kOe and magnetization measurements on iron and nickel single crystals in fields up to 148 kOe with vibrating sample magnetometers. The Mössbauer measurements give the hyperfine field H_n= H_int− (H₀−H_DM)+ΔH, where H_int is the hyperfine field at zero applied field, H₀ is the applied field, H_DM is the demagnetizing field, and ΔH is a term which would reflect a change in the magnetization at high field, …

Isomer-Shift Measurement In W182, S. G. Cohen, N. A. Blum, Y. W. Chow, Richard B. Frankel, L. Grodzins

Physics

No abstract provided.

Diffusion Of The Chlorine Ion In Potassium Chloride , Robert Fuller

Robert G. Fuller Publications

The diffusion coefficient of the chlorine ion was measured in pure single crystals of potassium chloride and in crystals containing mole fractions of strontium chloride between 2.1 x 10^-5 and 4.69 x 10^-4. The results were consistent with the assumption that both anion vacancies and vacancy pairs contribute to the diffusion of the chlorine ion. The diffusion coefficient of the chlorine ion in pure potassium chloride was well represented by the equation D=61 exp (-2.12±0.05 eV/kT) cm²/sec from 560 to 760 °C. The anion-vacancy contribution to the chlorine-ion diffusion coefficient in pure …

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 …

Electron Energy Spectrum From Ar+-Ar And H+-Ar Collisions, M. Eugene Rudd, T. Jorgensen Jr., D. J. Volz

M. Eugene Rudd Publications

Absolute differential cross sections have been measured for the ejection of electrons of various energies at 160° by argon ions and protons striking argon gas as a target. The observed energy spectrum consists of a number of "lines" or peaks superimposed on a continuous spectrum. The fine-structure regions occur below 20 eV and from about 120 to 220 eV for both projectiles. A number of lines are identified with auto-ionization transitions from neutral states and with Auger transitions from one- and two-vacancy states. With argon ions each peak has a "Doppler"-shifted counterpart due to electrons emitted from the moving particles. …

Radiation Damage Studies Of Libyan Desert Silica Glass, Farkhonda Hassan

Archived Theses and Dissertations

No abstract provided.

The Mössbauer Effect In Bismuth Ferrate, Bruce A. Banks

Masters Theses

"The magnetic hyperfine structure of the Fe⁵⁷ nuclei in bismuth ferrate was investigated using the Mössbauer effect. A Mössbauer effect spectrometer was built with consideration given to the elimination of vibration and the optimizing of the source, absorber, and detector geometries to produce the largest fractional Mössbauer effect per fractional standard deviation. The internal magnetic field at the Fe nuclei in BiFeO₃ was determined to (482 ± 9) kilooersteds at room temperature"--Abstract, page ii.

An Investigation Of The Control Of Hydraulic Fracturing Through The Inclusions Of Prefractures, William Joseph Kabeiseman

Doctoral Dissertations

"Among the methods for determining the in-situ state of stress within the earth’s crust, hydraulic fracturing has been and is receiving much attention. This method, in principle, measures stress directly with no delicate electronic equipment required nor knowledge of the elastic modulus of the material.

This dissertation investigates experimentally whether or not control of fracture orientation can be achieved by the introduction of circular and elliptical prefractures along with sand inclusions into cast hydrostone blocks which are hydraulically fractured. A mathematical model is presented and analytically solved for the stress condition associated with a circular crack containing fluid pressure with …

Calculated Cohesive Energy Of The Ordered Copper-Gold Alloy Cu Au I, Richard W. Hannum

Doctoral Dissertations

"The ordered alloy CuAu is the fifty atomic per cent alloy in the copper-gold system. It was observed by Johansson and Linde(1) and was one of the first ordered alloys to be studied by x-ray diffraction methods(Z, 3). Two ordered superlattices of CuAu are observed. CuAu I exists below 380° C and has a tetragonal structure which is a slight distortion of the face- centered cubic. It is very highly ordered, with all copper and all gold atoms in alternate (002) planes, as shown in Figure 2. CuAu II, which exists between 380° and 415° C, is orthorhombic in structure(4) …

Dynamics Of Disordered Harmonic Lattices, Daniel N. Payton Iii

Doctoral Dissertations

"Extensive numerical and analytic studies of vibrational spectra, normal modes, thermodynamic properties, and dynamical properties of harmonic systems with varying degrees of substitutional disorder have been made. The effects on observable properties of random mixtures of two or more species of atoms with differing masses and differing couplings to nearest-and next-nearest-neighbors have been investigated. Using the IBM-7030 digital computer, spectra for linear chains of 100,000 atoms have been obtained. Calculations in two and three dimensions have been limited to arrays of approximately 1000 atoms. Varying composition, mass ratio, and order affect the spectra in two and three dimensions in ways …

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 …

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.

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.

The Faraday Rotation And Dispersive Doppler Effects In The Ionosphere At Oblique Incidence, Charles Roland Baugher Ii

Masters Theses

"Integral equations for the isotropic and anisotropic ray path of a radio wave propagating through the ionosphere are developed. These equations assume a spherically stratisfied ionosphere and are equivalent to a detailed ray-tracing process. A method is devised to utilize these equations in the evaluation of combined Faraday rotation and dispersive Doppler data from earth satellites for subionospheric electron content. The method, which corrects for horizontal ionospheric gradients, is applied to data from the Explorer 22 satellite and some preliminary results are discussed"--Abstract, page ii.

The Construction Of A Multi-Threshold Foil For Fast Flux Measurements, Michael Henry Holkenbrink

Masters Theses

"The construction of a multi-threshold foil for fast neutron flux measurements is investigated. The factors governing the selection of the materials are the energy response of the given reactor, the half-life of the daughter, the prominent gamma ray emitted during decays, the power level of the reactor, the availability of adequate cross section data, and the alloying properties of the composite foil. A ternary system was chosen as a compromise between the difficulty of fabrication and the amount of information gained from one foil. The particular system chosen was In- P- Fe. The threshold reactions of these elements are In¹¹⁵ …

Absolute Soft X-Ray Dosimetry For Radiation Chemistry Studies, Howard Sajon Joyner

Masters Theses

"A homogeneous, variable plate separation ion chamber consisting of a polyethylene body and employing flowing ethylene as the cavity gas has been designed and tested for the specification soft x-ray (<75kV) energy deposition in typical hydrocarbons. The variable plate separation feature provided primary data on the differential specific ionization originating within the cavity gas occupying the effective collector volume which is independent of inherent chamber inhomogeneities associated with the electrically conducting films comprizing the chamber electrodes. These data demonstrated that charged particle equilibrium is established within the first few ten thousandths of an inch in typical solid hydrocarbons irradiated with this class of sources. Comparison of this type of chamber with a fixed plate separation, static cavity gas mode of operation showed that the latter may predict dose rates with inherent errors exceeding 100%. With the quality of electronic readout accessories presently available, the variable plate separation chamber yielded dose rate data exhibiting a probable error of 3.8 percent (plus the unknown uncertainty in the literature data on the energy required to form an ion pair), and an ultimate limiting error of less than 2 percent appears feasible"--Abstract, page ii.

Magnetic Structure Of Ga2−Xfexo3, R. B. Frankel, N. A. Blum, S. Foner, A. J. Freeman, M. Schieber

Physics

High‐magnetic‐field‐Mössbauer and magnetic‐moment experiments have been performed with Ga2−xFexO3. This magnetic system is of considerable interest because it is piezoelectric, weakly magnetic,1 and magnetoelectric.2 The crystal structure has been determined3 and a magnetic ordering inferred.3 The magnetic‐moment measurements were made using a vibrating sample magnetometer in fields up to 75 kOe. The samples used for the Mössbauer absorption experiments consisted of 57Fe enriched powders, grown from a flux, embedded in lucite, and having x=0.8 and 1.2. A mosaic absorber made of small x‐ray oriented single crystals was also studied. Measurements were made over the temperature range 4.2° to 320°K and …

Design And Construction Of A Pulsed Glass Laser, Mostafa Ibrahim Azab

Archived Theses and Dissertations

No abstract provided.

The Electrical Resistivity Of Different Types Of Glasses, Fadel Youssef Iskandar Assabghy

Archived Theses and Dissertations

No abstract provided.

Observation Of Doppler-Shifted Peaks In The Energy Spectrum Of Autoionizatioin Electrons From Ar+ -Ar Collisions, M. Eugene Rudd, T. Jorgensen, Jr., D. J. Volz

M. Eugene Rudd Publications

It is well known that when heavy ions traverse gas, electron pickup into excited states occurs. If the fast excited atom subsequently decays by radiating a photon, the energy of the photon will be Doppler shifted due to the motion of the source. This effect may be used to distinguish the radiation from stationary and moving atoms. For example, this method was used by Meinel to deduce the motion of solar protons streaming downward through the earth's atmosphere.
If instead the moving atom decays by autoionization, the ejected electron should also show a shift in energy analogous to the Doppler …

Analog Plotting System For Recording Energy Spectra Of Low Energy Charged Particles, M. Eugene Rudd

M. Eugene Rudd Publications

During recent measurements of energy spectra of electrons emitted from gases under positive ion bombardment an analyzing and plotting system was developed which has some unique features. Utilizing an electrostatic analyzer, it sweeps over the desired energy range and plots a graph directly in electron volts. With suitable modifications it could also be used for positive ions. Energies from near 0 to about 1000 eV have been plotted but this range could be extended. Usable graphs have been obtained at counting rates as low as 3 counts/sec.
Compensation is provided for fluctuations in the signal due to slow or rapid …

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 …

Theory Of The Lunar Photoelectron Atmosphere, Hal Emerson Mccloud Jr.

Doctoral Dissertations

"By considering the mechanics of an electron projected into an arbitrary potential field together with Poisson's equation it is possible to set up a differential equation for the electrostatic potential. The equation may be integrated and the photoelectron density found as a function of height for four approximate models. A simple model based upon monoenergetic photons and monoenergetic electrons ejected vertically upward yields rough estimates of the parameters of interest. Another model takes into account the fact that the photoelectrons are ejected at all angles. A general model takes into account the illumination of the lunar surface by solar (black …

Diffusional Drop Growth In A Supersaturated Atmosphere, John C. Carstens

Doctoral Dissertations

"The effect which a growing droplet has on the supersaturated atmosphere surrounding it is analyzed by assuming a macroscopic diffusional growth mechanism involving both heat and vapor. The problem is solved, for cloud-chamber conditions, first for very short times assuming a fixed radius, and then for longer times assuming the establishment of "quasi" steady-state conditions. Knowledge of the way in which droplet growth affects supersaturation is important in the evaluation of nucleation rates"--Abstract, page ii.

Re-Evaporation Nuclei And Evaporation In A Wilson Cloud Chamber, James G. Smith

Doctoral Dissertations

"Experimental techniques are developed for observing droplet evaporation in the submicroscopic size range. An expansion-compression cloud chamber with an atmosphere of tank helium saturated with water vapor is employed. This work was undertaken with the aim of examining submicroscopic droplet behavior and the existence of re-evaporation nuclei, a form of memory effect.

The theories of evaporation and nucleation on submicroscopic drop residues were re-examined, and alterations which appear to be consistent with the results of this work were incorporated into the evaporation theory.

The observed continually decreasing evaporation rate with diminishing droplet size confirms the existence of re-evaporation nuclei, but …

Ferrimagnetic Structure Of Magnetoelectric Ga2-XFeXO3, Richard B. Frankel, N. A. Blum, S. Foner, A. J. Freeman, M. Schieber

Physics

No abstract provided.