Digital Commons Network^™

The Use Of Surface Electromagnetic Waves To Measure Materials Properties, Ralph William Alexander, Robert John Bell

Physics Faculty Research & Creative Works

An Elementary Introduction to Surface Electromagnetic Waves (SEW) is Presented. the Emphasis is on Those Features of SEW Which Make Them Useful for Measuring Optical Properties of Thin Layers on Metals. the So-Called Two-Prism Technique for Making Such Measurements is Discussed, Some Preliminary Experimental Results Are Given, and Some Possible Applications Are Presented. © 1975.

Strain Effects On The Esr Spectrum From Antimony Donors In Germanium, Edward Boyd Hale, John R. Dennis, Shih Hua Pan

Physics Faculty Research & Creative Works

The electron-spin-resonance spectra from surface-strained (but not externally stressed) antimony-doped germanium are investigated in detail. Experimental data are given for the linewidth, line asymmetry, and line-shape reversal feature as well as for the changes in donor concentration, temperature, and surface conditions. The donors of interest occur in a surface layer several microns thick. A theoretical analysis is based on the Kohn-Luttinger formulation for a shallow donor electron, which is forced by surface strain to predominately occupy a [111] conduction-band valley minimum. A substantial distribution in strain among the donor sites is necessary to account for the line-structure features. These features …

Electron Impact Autoionization In Heavy Alkali Metals, Kaare J. Nygaard

Physics Faculty Research & Creative Works

Autoionizing levels in cesium, rubidium, and potassium have been studied by electron impact in a crossed-beam apparatus. Comparisons are made with the binary-encounter calculations of Roy and Rai. The effects of autoionization and inner-shell ionization have been overestimated in the theory. © 1975 The American Physical Society.

A High-Power Pulsed Xenon Ion Laser As A Pump Source For A Tunable Dye Laser, Laird D. Schearer

Physics Faculty Research & Creative Works

An inexpensive pulsed xenon ion laser with peak power outputs up to 4 kW has been constructed and used as a pump source for a tunable rhodamine 6G dye laser with a 0.25-A bandpass in the yellow-red range of the spectrum. The dye laser is tunable from 5465 to 6300 A. Over 50 W are obtained at the peak of the tuning range. Copyright © 1975 by The Institute of Electrical and Electronics Engineers, Inc.

The Application Of Impact Dampers To Continuous Systems, Ranjit K. Roy, Richard D. Rocke, J. Earl Foster

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A study has been made of the application of impact dampers to two types of continuous systems, a simply supported and a clamped beam. Experimental models were tested in the laboratory and computer programs were developed to calculate response by two separate approaches. Results from calculations agreed favorably with experimental tests. Curves presented show the response to be expected for values of significant system parameters and enable the user to apply impact dampers to these types of continuous systems. © 1975 by ASME.

Transport Phenomena In Thermally Stratified Boundary Layers, D. W. Pepper, S. C. Lee

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Studies of heat, mass, and momentum transfer are made to analyze the formation of marine fogs in thermally stratified boundary layers in the atmosphere. The governing partial differential equations of continuity, momentum, temperature, and concentration are used to describe the transport phenomena. An additional equation of turbulence energy is introduced to account for the development of the turbulent motions. Simultaneous solution of this system of equations allows the turbulent exchange coefficients to be treated in the same way as all other dependent parameters. Verification of the theoretical approach is made by comparing the numerical predictions with wind tunnel simulations of …

Measurement Of Growth Rate To Determine Condensation Coefficients For Water Drops Grown On Natural Cloud Nuclei., A. M. Sinnarwalla, Darryl J. Alofs, J. C. Carstens

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Growth Rate Measurements Were Made for Water Drops Grown on Nuclei in Atmospheric Air Samples Taken in Rolla, Missouri. Rolla, Having a Population of 15,000 and Very Little Industry, is Relatively Free of Urban Pollutants. the Measurements Were Made in a Vertical Flow Thermal Diffusion Chamber at Supersaturations of 0. 5 and 1%. the Time to Grow from Near Dry Radius to the Final Radius (6 to 7. 5 Mu M) Was Measured. If One Assumes the Thermal Accomodation Coefficient is Unity, the Measurements Indicate an Average Value of 0. 026 for the Condensation Coefficient. the Temperature Ranged from 22. …

Computer Modeling Of The Statistical Properties Of Transionospheric Scintillation Channels, W. F. Deckelman, Rodger E. Ziemer

Electrical and Computer Engineering Faculty Research & Creative Works

This concise paper shows that a bandlimited bivariate-normal time series is a useful model for the envelope of scintillating radio signals traversing the ionosphere. A software model is presented whose generated time series is compared to an actual block of scintillation data. A comparison of computer-generated and actual scintillation data shows that the fade-duration distribution of the simulated data fits that of the actual data closely through proper choice of model parameters. Copyright © by 1975 The Institute of Electrical and Electronics Engineers, Inc.

Analysis Of The Stresses Induced In Rock By Rock Splitters., Diogenes De Jesus Chollett

Masters Theses

"The method of solution of the problem of determining the stress and displacement distributions around an unfractured circular hole subjected to nonuniform applied internal pressure located in an infinite plate is developed. Two problems are solved for two different representative boundary conditions. The problem of determining the stress distribution around a circular hole with two symmetric radial cracks subjected to nonuniform applied radial pressure located in an infinite plate is analyzed and developed for further solution"-- Abstract, p. ii

Thermal Stresses In A Sphere Due To Local Heating Followed By Complete Cooling, T. S. Chen, K. Thirumalai, J. B. Cheung

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

Use Of The Psi Technique In Prerequisite Courses, John T. Park, William R. Snow

Physics Faculty Research & Creative Works

An engineering physics course, in which the Personalized System of Instruction (PSI) technique has been used, has been designed to meet the requirements that all of a prescribed list of subjects be covered and that the course be completed within a single semester. The course was modified so that it has two levels of mastery for each unit: a passing level and a complete mastery level. All students were required to reach a passing level of mastery on all of the required material. Grades were assigned according to the number of complete mastery level examinations passed. It was found that …

Photoionization Of The 6p32,122 Fine-Structure Levels In Cesium, Kaare J. Nygaard, Robert E. Hebner, James A. Jones, Robert J. Corbin

Physics Faculty Research & Creative Works

The relative photoionization cross sections for cesium atoms selectively excited to the 6P32,122 states have been measured in a triple-crossed-beam experiment. A cesium discharge lamp produced resonant wavelengths of 8521 and 8944 for the excitation process. A Hg-Xe lamp combined with a grating monochromator was used for the actual ionization in the wavelength region from 2500 to 5000. Background counts due to photoionization of ground-state cesium atoms and dimers as well as various surface effects were discriminated against by chopping the excitation light source. The data are compared with results from radiative-recombination measurements in which the fine-structure levels are not …

Generalized Likelihood Signal Resolution, John A. Stuller

Electrical and Computer Engineering Faculty Research & Creative Works

This Paper Defines an M-Ary Generalized Likelihood Ratio Test (MGLRT) that overcomes Root's Early Objection to the Application of Generalized Likelihood Ratio Testing to the Resolution of Correlated Signals. the Proposed Test Extends the Form of a Conventional Binary Generalized Likelihood Ratio Test (GLRT) in a Manner that Permits a Generalization of the Minimax Properties of the Binary Test to the M-Hypotheses Case. When the Estimated Signals Are Orthogonal, the Test Reduces to a Sequence of Conventional Binary Tests Duplicating the Performance of a Narrow-Band Matched Filter Envelope-Detector Receiver. © 1975, IEEE. All Rights Reserved.

A Unit Hydrograph For The Missouri Ozark Region., Melvin G. Schaefer

Masters Theses

"Eleven small watersheds from the Missouri Ozark region are used in generating a synthetic unit hydrograph. The analysis is composed of three parts: First, a prediction equation is developed which correlates the time lag parameter with the physical features of the watershed. Second, an equation is developed which predicts the peak flow ordinate for 30-, 60- and 120-minute unit hydrographs. Third, an average dimensionless unit hydrograph is determined"-- Abstract, p. iii

Theoretical And Experimental Investigation Of A Viscous Ring Nutation Damper., Roy Alexander Campbell Iii

Masters Theses

"The dynamics of passive dampers applied to high s peed gyro systems is reviewed briefly and the partially filled viscous ring nutation damper is investigated. Particular attention is given to 1 the broken ring or nutation synchronous configuration where the fluid moves as a rigid slug and the damping is greatest. In this mode the damping is assumed to be viscous and expressions for a linear damping constant are presented. Data from an experimental, high-speed gyro is used to verify the theoretical analysis"-- Abstract, p. 1

A Strategic Planning Model For Implementing Community Development Block Grant Programs., John M. Lang

Masters Theses

"As problems of metropolitan areas have multiplied, the federal government has been drawn into an ever-increasing intimate funding association with city governments. Although federal funding for ii urban problems may have been considered a panacea by some, most local government agencies have now discovered that their problem has shifted in emphasis from where to find funds to that of meeting federal standards and requirements of application in order to get the funds.

The impact of federal programs on local government management is evident in the recently enacted federal Housing and Community Development Act of 1974. Title I of the act …

A Study Of Middle To Late Quaternary Sediments In The Karst Trap., David Lewis Rath

Masters Theses

"Quaternary deposits preserved in a karst trap on the Lebanon uplands a e described. The sediments represent the Yarmouthian, Illinoian, Sangamonian, and Wisconsinan Stages. The karst trap is pre-Yarmouthian in age. The lowermost deposit consists of residual fill material on which lies a well-developed Yarmouth paleosol. During the Illinoian Stage about 61 cm (2 feet) of Loveland loess was deposited over the area. Toward late Illinoian conditions favoring erosion rapidly filled the closed system, stripping the loess and reducing the residual slopes. The system stabilized during the Sangamonian Stage allowing for a thick, strong Sangamon paleosol to deve lop on …

The Influence Of Oxygen Activity On Sintering Of Strontium Doped Lanthanum Chromite., Leslie Groupp

Masters Theses

"The influence of oxygen activity upon the sintering of lanthanum chromite (La_1-xSr_x CrO₃) with x ranging from Oto 0.2 was investigated using chemically prepared powders of <0.1 microns particle size. The results show that at a temperature of 1740 ° C densities of >92% of theoretical could be achieved if the oxygen activities were maintained in the 10^-11 to 10^-12 atm. range. If oxygen activity exceeds 10^-10 atm., densities of not >80% theoretical could be obtained. For the compositions studied, room temperature X-ray analysis of both the starting powders and sintered compacts show the compositions to be orthorhombic and single phase. The ambient lattice parameters and resistivity measurements decreased …

An Experimental Study Of Mass Transfer To Droplets In Aqueous Polymer Solutions., Richard Gerard Schafermeyer

Masters Theses

"Instantaneous and time-average mass transfer coefficients for 1 the free-fall period was obtained for transfer of iodine from nonNewtonian continuous phases to carbon tetrachloride drops. The nonNewtonian continuous phases were aqueous solutions of carboxymethyl cellulose and carboxy polymethylene. Although a few exceptions were found, the continuous phase mass transfer coefficients were, in general, found to decrease with increasing time of drop contact. Comparisons of the experimental data to theoretical relations showed that changes in drop internal circulation probably occurred for that data which showed a time effect for the mass transfer coefficient. Several explanations for the time effect were offered, …

Computer Simulation Of Radiation Effects In Fe₃Al By Using Alternating Direction Implicit Numerical Techniques., Dean Lewis Tibbitts

Masters Theses

"An analysis was conducted to see if the alternating direction implicit (a.d.i.) numerical technique could be applied to a many-body dynamical radiation damage model.

The computer program which resulted was named ADI. It was numerically stable for small time steps used in conjunction with low ev knock-ens. It was also able to relax the a toms in the system simultaneously in the implicit direction. However, an existing explicit computer code, which was to be replaced by ADI, proved to be more numerically stable and about 40% faster"-- Abstract, p. ii

A Study Of Stability Of Ac And Dc Transmission Lines Operated In Parallel., Tzyy-Cheng Wang

Masters Theses

"This thesis is concerned with the analysis, optimization and simulation of parallel operation of ac and de transmission lines.

An introduction and literature review are provided to give background information on how the parallel operation should be considered. The parallel system is analyzed, and the state equation is derived for determining the stability limit. The optimization of the control law U = Fx is determined by a standard quadratic cost function. Prefault, during fault and postfault situations in the parallel operation has been simulated by Continuous System Modeling program. Some comparison and comments are made between 1 ac, 1 de …

Computational Models Of Learning., Kenneth Jesse Marse

Masters Theses

"An investigation is made into the use of techniques which would normally be described as learning if encountered in a human being. A literature review of several subject areas including game-playing computer programs, automatic control systems, pattern recognition methods, and biological modeling is performed, with the purpose of extracting and examining those processes which exhibit learning. A general model of the type of learning most widely utilized in these areas is constructed and used to compare and contrast specific models which describe the learning techniques employed. Some specific models which do not exhibit learning as described by the general model …

Heavy Metal Contamination In Soil Around A Lead Smelter In Southeast Missouri, David Lewis Butherus

Masters Theses

"In order to determine the extent of possible heavy metal contamination, more than 963 samples of leaf litter and soil were collected from 410 sample stations around the AMAX smelter in southeast Missouri. Dried samples of leaf litter and minus 80 mesh soil fractions were analyzed for cadmium, copper, lead, and zinc by atomic absorption spectrophotometry. Minus 80 mesh soil fractions were also analyzed for sulfur using x-ray fluorescence methods. Ranges of heavy metal concentrations in leaf litter were: cadmium, 0.13 μg/g to 175 μg/g; copper, 4.2 μg/g to 6500 μg/g; lead, 50 μg/g to 130,000 μg/g; and zinc, 26 …

An Analysis Of A Network Of Finite-Queue, Multiple-Server Facilities., Juanita Kaye Shukers Grau

Masters Theses

"An algorithm for listing all possible steady states and for generating the transition matrix for a series of finite-queue, multiple-server facilities is described. This algorithm is compared to a previously developed one. The new algorithm is better since it works for multiple servers and does not require an extra pseudo-facility. Using the list of states and the matrix generated by the new algorithm, exact steady state probabilities can be calculated. Then the probabilities can be used to obtain system statistics which cannot be calculated otherwise"-- Abstract, p. ii

A Study Of Product Inhibition In The Reaction Of P-Nitrophenyl- Α - D - Glucoside Catalyzed By The Enzyme Glucoamylase I., Mark L. Dickhaus

Masters Theses

"The entire time course of the hydrolysis of p-nitrophenyl-a-D-glucoside by the enzyme glucoamylase I was followed spectrophotometrically. Using time versus absorbance data the constants in the Michaelis-Menten equation were determined. The effect of the addition of product to the initial reaction mixture and the effect of solvent and temperature were determined. It was found that product produced during the reaction did not have the same effect upon the rate as did product added initially to the reaction mixture. The presence of substrate caused the enzyme to acquire protection against inhibition by the product"-- Abstract, p. ii

Vapor Pressures For The Ternary System 1-Butene, Isobutane, And 1, 3-Butadiene., Kevin Steele

Masters Theses

"An innovative apparatus suitable for the rapid but accurate measurement of vapor pressures of liquid solutions is described. Liquid solutions of known composition are prepared in a test cell by volumetric metering of degassed liquids. The operation of the apparatus is feasible over a wide range of temperature and pressure, producing data with an estimated probable error of ± 0.05 percent. Experimental P-X data for a system of C₄ hydrocarbons (1-Butene, Isobutane, and 1,3- Butadiene) are reported from 40-160 degrees Fahrenheit. The data are in agreement with the literature, and vapor pressures are expressed as a function of temperature …

Performance Evaluation Of Linear Systems Using The Fast Fourier Transform., Larry Leonard Lamano

Masters Theses

"In order for a computer simulation of a communication system to yield useful and meaningful results, a method for determining system performance is often essential. The computer postprocessor, described in this thesis, allows accurate determination of the mean-square-error induced by the system being simulated and the noise power at any point in the system.

Measurements of the mean-square-error induced by a system due to amplitude distortion, phase distortion, and amplitude and phase distortion, along with measurements of the power in a Gaussian noise waveform are performed. The values obtained using simulation are compared to the corresponding theoretical values in order …

A Study Of The Effects Of Numerical Error Propagated Through Several Independent Stages: An Electron Optics Simulation., William Donald Webster

Masters Theses

"Presented is a study, combining numerical methods in a series of stages whereby each stage provides input data to its successor. A model problem from electron optics ii is studied in which a potential field is computed, gradient vectors calculated, and trajectory equations solved. Error effects in each stage is assessed for its influence on the final results of the numerical process mimicking the model problem. Error analysis is given in Appendix A. Finally, the superiority of Spline approximations for estimating derivatives is demonstrated"-- Abstract, p. ii

Reflected Surface Waves From A Vertical Discontinuity., Jesus Manuel Aboud

Masters Theses

"Surface waves generated in the field by small explosions were observed along lines parallel and perpendicular to a vertical discontinuity in a surface layer. Three types of wave particle motion were observed in waves incident on the discontinuity: retrograde, progressive, and shear (SH). Waves of the last two types were intense enough to observe a reflection, permitting calculation of reflection coefficients. The results demonstrate the feasibility of using reflection measurements to locate a discontinuity such as a fault zone"-- Abstract, p. ii

A Study Of Several Substitution Ciphers Using Mathematical Models., Wanda Louise Garner

Masters Theses

"This paper will consider vector and matrix representations for several polyalphabetical substitution ciphers. Classical ciphers such as the Vigenère, the True Beaufort, the Variant Beaufort, and the autokey will be included. We shall also discuss ways to mathematically vary a substitution cipher. In addition, we shall employ our mathematical representations to decipher a fixed matrix substitution cipher"--Abstract, p. ii