Physical Sciences and Mathematics Commons^™

Tchebycheff Approximation On A Discrete Point Set: Algorithms Old And New, William Edward Mcbride

Doctoral Dissertations

"Several linear and nonlinear algorithms for solving the discrete Tchebycheff problem are compared in this study. The Lawson algorithm is compared with two more well-known methods of linear Tchebycheff approximation. A new acceleration scheme for the Lawson algorithm is introduced and its performance is tested with an already existing acceleration technique. The new version is found to be better than the previous one but not as effective as the traditional Exchange method.

A nonlinear version of Lawson's algorithm is proposed for the solution of problems having approximating functions which are varisolvent. Some linear theorems of Lawson are extended to the …

The Contribution Of Phonon-Induced Tunneling To Donor Esr Spectral Narrowing In Semiconductors, David Lawrence Meier

Masters Theses

"The narrowing of donor electron spin resonance spectra with increasing donor concentration N_D and increasing temperature T has been observed in semiconductors in the past. One proposed explanation for this phenomenon has been narrowing due to electron motion caused by phonon-induced tunneling (hopping) between donor sites. According to the Anderson narrowing theory, the line width of the narrowed line can be expressed in terms of the average square spread of the non-narrowed spectrum, < H²>_ave, and the average frequency of electron motion, ω_n. Previous work has been done on narrowing by hopping, but rigorous expressions for ω …

Total Electron Impact Ionization Cross Section In Rubidium From Threshold To 250 Ev, Kaare J. Nygaard, Yu Bong Hahn

Physics Faculty Research & Creative Works

A study of ionization in rubidium has been made in a crossed atom-electron beam apparatus. At an electron energy of about 10 eV there is a maximum in the cross section corresponding to the maximum probability for removal of the 5s valence electron. At 16.5 eV we have observed a new peak that is caused by the mechanism of autoionization. For energies below 30 eV there is a good agreement, both in shape and magnitude, between the present measurements and the empirical formula of Lotz. The over-all uncertainty in the measurements is ± 12% which is mostly accounted for by …

Adsorption Of Water On Gold, Jean-Marc Louis Deschanel

Masters Theses

"Water adsorption isotherms on gold films were measured with a quartz crystal microbalance. Two gold films were studied: a "dirty" gold film contaminated by approximately one monolayer of carbon, and a "clean" gold film prepared by evaporating gold from a heated tungsten wire under high vacuum.

Water was found to chemisorb on both films according to a Freundlich type adsorption isotherm. Isosteric heats of adsorption were computed from the isotherm data. On the "clean" gold surface the isosteric heat showed a logarithmic decrease with increasing water coverage. The highest measured value for the heat of adsorption was 35 kcal mole …

Structure And Chemical Composition Of The Otoliths Of Cyprinus Carpio, Larry Paul Coen

Masters Theses

"The need for the study of microfossils such as foraminifera, conodonts, and otoliths as stratigraphic tools has been well established. However, disarticulated parts such as otoliths and conodonts cannot be effectively used unless they can be recognized. Otoliths, although somewhat unrecognized in the geological record, are far more abundant than articulated skeletons (Frizzell, 1965, p. 86). Therefore, much investigation is being conducted to reveal the origin, function, morphology, and usefulness of the otoliths of fishes.

In this investigation, the asteriscus, well developed only in Ostariophysins (of which the carp is a member), is studied for morphology. New tentative terms are …

A Study Of A New Hydrometallurgical Treatment For New Lead Belt Chalcopyrite Concentrates, Larry Steven Livingston

Masters Theses

"A two-phase research project was conducted on chalcopyrite concentrates from the New Lead Belt of Missouri. Phase one includes an ore microscopy study of the Magmont and Viburnum chalcopyrite concentrates in respect to mineralogy, particle size and interlocking characteristics of ore minerals and their possible relationships to poor chalcopyrite-galena separation in the copper flotation circuits.

Results of the ore microscopy study of the Magmont and Viburnum mines chalcopyrite concentrates suggest that interlocking of chalcopyrite and galena are not the cause of poor chalcopyrite-galena separation in the copper flotation circuits.

The most common sulfides found in the Magmont and Viburnum chalcopyrite …

Distribution Of Trace Elements In Host Rock Limestone In The Tri-State Zinc-Lead District, Dinesh Jashbhai Patel

Masters Theses

"The trace metal contents of limestone in the Tri-State zinc-lead district were determined within a single horizon, the M bed. Ninety-six specimens, collected for a previous study of their petrographic character, were analyzed for zinc, lead, and copper using atomic absorption spectrophotometric techniques.

The unaltered M bed limestone at a distance from ore bodies was found to contain only 12-28 ppm zinc, 40-SO ppm lead and 12 ppm or less copper. Those limestone specimens which were found b earlier petrographic study to be altered principally to sparry calcite commonly contain anomalous amounts of zinc and lead. Some also have slightly …

Heavy Metal Concentrations In The Waters Of The Springfield Area, Missouri, Anita Louise Williams

Masters Theses

"Water samples consisting of streams, springs, lakes, deep wells, and shallow wells were collected from various locations around the Springfield area. These were analysed for concentrations of the heavy metals of lead, copper, cadmium, zinc, mercury, and iron. Heavy metal contents in the waters occasionally show local concentrations. The zinc content can be related to known minor mineralized areas around Springfield. Some iron content in the surface waters and shallow aquifers is contributed by the iron-bearing clays and pyrites in the shallow formations.

The ranges of heavy metal values in the Springfield area are in ppb: lead, 1 to 70; …

Charge Transfer Between Oˉ Ions And O₂ Molecules In The Ground State And Singlet Delta Excited State, Ronald Floyd Mathis

Doctoral Dissertations

"A crossed-beam apparatus has been built and used to study charge transfer between O⁻ ions and O₂ molecules in the ground state and in the metastable, singlet delta, excited state. The energy of the incident ions ranged from 10 to 10,000 eV.

The cross section for charge transfer between O⁻ and ground state O₂ was found to peak at about 5 keV, as predicted on the basis of the Rapp and Francis theory. At the lower energies there is good agreement with the previous measurements of Snow et al., and Rutherford and Turner, who also used crossed beam techniques. The …

Hall Effect Measurements Of The Net Ionic Mobility In Nacl, Nabr And Nai, Suman Kumar Hukku

Doctoral Dissertations

"Ac Hall effect measurements of the net ionic mobility, µ_H, in "pure" NaCl, NaBr and Nal were made over their intrinsic temperature ranges extending up to about 250⁰ C below the crystal melting point. A well characterized detector system was employed which provided a mobility sensitivity ≥ 2 x 10^-4 cm² · V^-1 · s^-1. Complementary electrical conductivity, σ, data was also collected. The charge transport was assumed to be due to Schottky defects and both cation and anion contributions were considered. The high temperature anion contribution to mobility was clearly demonstrated by …

A Stochastic Theory Of The Stepwise Growth Of Ice Crystal Surfaces, Andreas Kasimir Goroch

Doctoral Dissertations

"Previous theories have had limited success in explaining the presence of a peak in the behavior of the rate of advance of a step on an ice crystal surface with respect to temperature. In the present work we examine the temperature dependence of the advance of steps on the basal face of an ice crystal from several points of view. An alternate derivation is presented for the random motion of adsorbents on a cubic lattice with absorbing points, and this theory is applied for the advance of a step on an ice surface. The velocity of step advance according to …

A Study Of The Pulse-Height Response Of Silicon Surface-Barrier Detectors To High-Energy Heavy Ions, Gregory Dan Smith

Doctoral Dissertations

"The pulse-height defect (PHD) of high-energy heavy ions in silicon surface-barrier detectors can be divided into three components: (1) energy loss in the gold-surface layer, (2) a nuclear-stopping defect, and (3) a defect due to recombination of electron-hole pairs in the plasma created by the heavy ion. The plasma recombination portion of the PHD was the subject of this study using the variation of the PHD with (1) the angle of incidence of incoming heavy ions, and (2) changes in the detector bias. The Tandem Van de Graaff accelerator at Argonne National Laboratory was used to produce scattered beam ions …

Some Results On Quasi-Uniform Spaces, Karen Sylvia Carter

Doctoral Dissertations

"An example of a quasi-uniform space which is complete but not strongly complete is constructed. We also give an example to show that a T₁ space does not necessarily have a T₁ strong completion.

The definition of Cauchy filter is discussed. An alternate definition, referred to as C-filter, is considered. A construction of a C-completion is given and it is shown that if a quasi-pseudometric is complete, then the corresponding quasi-uniform structure is C-complete.

Conjugate quasi-uniform spaces are discussed. A theorem relating a transitive base of a quasi-uniform structure to a transitive base of the conjugate structure is …

The Atomic Absorption Determination Of Ultra-Trace Tellurium In Rocks Utilizing High Sensitivity Sampling Systems, Richard D. Beaty

Doctoral Dissertations

"The sampling boat and the graphite furnace have been shown to possess the required sensitivity to detect tellurium at ultra-trace levels, in a variety of sample types, by atomic absorption. In the sampling boat approach, tellurium in sample solutions is chemically separated and concentrated by extraction into methyl isobutyl ketone before measurement. For samples exhibiting extraction interferences or excessively high background absorption, a preliminary separation of tellurium by coprecipitation with selenium is described. Using this technique, tellurium can be quantitatively detected down to 5 nanograms and linear response is observed to 100 nanograms. Relative standard deviations of better than 7% …

Note On The Poisson Distribution, I. Adawi

Physics Faculty Research & Creative Works

No abstract provided.

Absolute Differential Elastic- And Inelastic-Scattering Cross Sections In 25-140 Kev He+ + He Collisions, Victor Pol, Walter Kauppila, John T. Park

Physics Faculty Research & Creative Works

Data obtained as energy-loss spectra at angles from 0 to 7.3x10-3 rad (c.m.) with typical energy-loss resolution of 0.7 eV and angular resolution of 2x10-3 rad (c.m.) were used to calculate average differential cross sections dσdΩav for elastic scattering, direct excitation of the individual He(n=2) states, and direct excitation of the He+(n=2) states. The total cross section for excitation of the He(n=2) states obtained by integrating the differential cross sections was found to be 20x10-18 cm2 at 25 keV (lab) decreasing to 7x10-18 cm2 at 140 keV. At incident lab energies below 100 keV the He(2S2) and He(2P3) states dominate …

Laser Scattering Measurements Of Droplet Growth In Binary Mixtures. Ii. H2o And Argon H2o And Helium, M. A. Viettit, Burton Schuster

Physics Faculty Research & Creative Works

Water droplet growth rates in a Wilson cloud chamber were measured in Ar-H2O and He-H2O media. These rates were determined in the size range 0.45-10.0 u.m by detection of oscillations in the intensity of polarized light from a He-Ne laser source scattered at 30° by the droplet population. Pressure and initial temperature were measured in the chamber for use in the computation of three droplet growth theories for comparison to experiment. Experiments were conducted in supersaturations ranging from 1.04 to 3.45.

Possible Applications Of Surface Electromagnetic Waves To Measure Absorption Coefficients, Ralph William Alexander, Robert John Bell, C. A. Ward, James Roger Weaver, I. L. Tyler, B. Fischer

Physics Faculty Research & Creative Works

We Show that Surface Electromagnetic Waves Can Probably Be Used to Measure the Absorption Coefficients of Materials overlaying Metals. the Proposed Experimental Method is Illustrated in the Infrared Frequency Range using Water, Teflon, and Polyethylene as Sample Materials.

Gaas Laser Experiments For The Undergraduate Laboratory, R. E. Robert, Daniel J. Jones, Kaare J. Nygaard

Physics Faculty Research & Creative Works

No abstract provided.

Penning Ionization Of Zn And Cd By Noble-Gas Metastable Atoms, L. A. Riseberg, William F. Parks, Laird D. Schearer

Physics Faculty Research & Creative Works

The Penning-ionization cross sections for He, Ne, Ar, and Kr metastable atoms with Zn and Cd have been measured in a pulsed afterglow. Within the framework of existing theories we have determined those parameters which are of importance in collisions of this type. We find that our data are internally consistent if the cross sections are proportional to the cube of the "hard-sphere" radii and the effects of selection rules are included. A theoretical basis for this dependence is suggested. © 1973 The American Physical Society.

On The Effect Of Cesium In Photoionization Laser Plasmas, Kaare J. Nygaard

Physics Faculty Research & Creative Works

A number of photoionization mechanisms and how they can be used to generate large-volume laser plasmas are discussed. Reaction rates for two-step photoionization of the cesium atoms as well as formation of molecular ions (Cs2+) are estimated. The necessary cross-section data were obtained from related research in thermionic energy converters. © 1973, IEEE. All rights reserved.

Scavenging Of Atmospheric Particles By Water Drops, Ming-Shian Wu

Doctoral Dissertations

"In the first paper, the mechanisms of particle capture and coalescence of aerosols by a moving water drop in the atmosphere are studied using the boundary-layer flow approximation. The particle trajectory is computed by solving the equations of motion of the particle both outside and inside the boundary layer using the Adams-Moulton method. The grazing trajectory is found by a trial-and-error technique. The collision and collection efficiencies of scavenging due to particle inertia and to the velocity gradient of the flow field are then computed for water drops ranging from 0.1 to 1.0 mm in radius and for particle of …

Auger Satellites Of The L₂₃ Auger Emission Bands Of Al, Si, And P, John Junior Melles

Doctoral Dissertations

"In this study a detailed investigation of the high energy satellites of the L₂₃ Auger emission bands of Al, Si, and P was made. The satellites are interpreted as arising from double ionization of the L₂₃ shell rather than from a plasmon gain process. The parent-satellite energy separations, ΔE, between like structures were determined and were found to be consistently smaller than the volume plasmon energies measured for the same samples. A comparison of Si and SiO revealed no evidence that ΔE for Si is dependent on the volume plasmon energy of the sample.

The satellite threshold excitation …

Paleozoic Stratigraphy As An Ore Control Of Hydrothermal, Base-Metal, Sulfide Deposits In New Mexico, John Samuel Sullivan Jr.

Doctoral Dissertations

"Until now the concept or regional stratigraphic control of hydrothermal ore deposits has not received much attention in the literature as a possible exploration guide for locating additional ore bodies. This concept is applied on a regional scale to Paleozoic strata in thirteen mining districts with hydrothermal base-metal deposits in a 35,300 square mile area or southwest New Mexico.

The rocks at the stratigraphic position of the ore-zones are characterized as massive- to thick-bedded with less than 5 percent chert present. The rocks are abundantly to moderately fractured. Fine- to medium-grained dolomite is the dominant host-rock in the lower Paleozoic …

Model Correction For The Formation Of Amorphous Silicon By Ion Implantation, John Robert Dennis

Masters Theses

"ESR has been used to study the formation of an amorphous layer in silicon by ion implantation. The room temperature implants were done at 20 keV with low dose rates. The critical dose was determined as a function of ion mass for six different ion species. Our experimental heavy ion results agree with those found by other ESR investigators at higher energy, but are not the same for light ions. However, our light and heavy ion results agree with electron microscope measurements for low energy implants. An energy-independent model for the formation of amorphous silicon by ion implantation has …

Temperature Dependence Of The Formation Of An Amorphous Layer In Ion-Implanted Silicon, Gary Keith Woodward

Masters Theses

"Electron spin resonance (ESR) has been used to study the temperature dependence of the formation of an amorphous damaged layer produced by ion implantation in silicon.

Undoped silicon wafers were implanted with N⁺, Ar⁺, and Kr⁺ ions at 20 keV and dose rates less than .36 µa/cm². Implant temperatures ranged from room temperature to 250°C. ESR measurements were made at room temperature on these wafers. The only ESR signal found was that associated with amorphous silicon. The ESR signal amplitude for a given ion and temperature increased approximately linearly with dose up to …

A Study Of The Ability Of Surface Active Materials To Increase The Evaporation Rates Of Small, Freely Falling Water Drops, David Alan Sierawski

Masters Theses

"The evaporation rate at 30°C of water droplets partially covered by surface active materials (SAM) were determined. While two of the SAM were studied at a single dew point depression (ΔT_DP), seven others were examined over a range of ΔT_DP values. It was found, by comparison with pure water drops under identical conditions, that SAM increases the evaporation rate as compared to the rate of an uncontaminated drop. The lack of effect of the hydrophobic chain length and the possible effect of the hydrophilic group on this phenomenon are discussed. The explanation proposed is that at 30°C …

Desorption Of Phosphorus From Si (111) Surfaces, Cesar Michel Magnin

Masters Theses

"Auger electron spectroscopy and mass analysis are used as complementary methods in evaluating desorption kinetics. For phosphorus on silicon, the order of desorption and activation energies of desorption are determined from continuously monitored phosphorus Auger electron signals during heating. These measurements indicate that diatomic phosphorus dissociates when adsorbed onto clean silicon. Mass spectrometer flash desorption spectra show that at least four distinct surface bonds are associated with the desorption of phosphorus. The dominant desorbed species is diatomic phosphorus at high coverage (> 0. 1 monolayer) and atomic phosphorus at low coverage (< 0.07 monolayer)"--Abstract, page ii.

Corals Of The St. Louis Limestone In The Area Of Calhoun County, Illinois And St. Louis County, Missouri, William Earl Collins

Masters Theses

"The St. Louis Limestone and its equivalent formations crop out from Alaska south to Sonora and from Arizona east to Virginia. The St. Louis, in most cases, is fossiliferous and contains numerous species of foraminifers, echinoderms, bryozoans, molluscans, brachipods, arthropods and coelenterates. Algal mounds and mats are common. The rugose coral fauna of the Middle Mississippian (Meramecian) St. Louis Limestone of southern Calhoun County, Illinois and northern St. Louis County, Missouri was studied to determine first what corals were present and second the validity of the names assigned to the previously described species. It was found that the binomen for …

The Design And Calibration Of A Vibrating Sample Magnetometer, Donald Dwight Hoffman

Masters Theses

"The design and calibration of a vibrating sample magnetometer is described. The sample motion was in the direction of the external magnetic field which was produced by a superconducting solenoid. The maximum external magnetic field was 70 kilogauss. Sample temperature could be varied from 77°K to 1000°K with a vacuum jacketed furnace. The maximum temperature was obtained with approximately 27 watts. The instrument was calibrated to 1% with a spherical nickel sample"--Abstract, page ii.