Engineering Commons^™

A Crystallographic Study Of The Pbzro₃-Pbtio₃-Bifeo₃ Ternary System., Dannie R. Clarida

Masters Theses

"The purpose of this investigation was to conduct a crystallographic study of the PbZrO₃-PbTiO₃-BiFeO₃ ternary system, where all three components are perovskites. Lead zirconate is antiferroelectric, lead titanate is ferroelectric, and bismuth ferrate is thought to be ferroelectric. X-ray diffraction analysis was employed to determine the crystallographic structure and lattice parameters.

A tetragonal region was found to exist in the area of high PbTiO₃ content. A rhombohedral region occurred in the remainder of the system with high BiFeO₃ and PbZrO₃ content, except for an orthorhombic envelope along the PbZrO₃-BiFeO₃ side of the diagram up to approximately 70 per cent BiFeO₃.The …

Some Effects Of Sodium Pentachlorophenol On Activated Sludge And Minnows., James Albert Heidman

Masters Theses

"The primary purpose of this investigation was to determine the effect of sodium pentachlorophenol on activated sludge. An additional objective was to determine the toxicity of sodium pentachlorophenol to minnows.

All activated sludge units were grown on a glucose and mineral nutrient waste. In addition, a unit acclimated to 100 and 250 mg/1 of sodium pentachlorophenol was also studied. The effect of a shock loading of sodium pentachlorophenol was found to depend on the concentration of the loading and also on the group of micro-organisms which were predominating. One activated sludge system was seriously impared at a shock loading of …

Slope Stability Analysis Of A Fissured Glacial Clay, Byron G. Walker

Masters Theses

"A slope in an over-consolidated, fissured clay was analyzed by the Swedish Method of Slices.

Values of cohesion (c) and angles of friction (Ø) were determined by three different types of direct shear tests (undrained, drained and residual).

Factors of safety (functions of c and Ø) indicated that the direct shear test parameter gave a factor of safety approximately four times that represented by failure conditions in the field. Drained tests gave a factor of safety nearly 2.3 times the value represented by field conditions. The conclusion is made that these two tests are of limited value for slope stability …

The Construction Of A Fermi Neutron Chopper For Cross Section Measurements, Cleon Marion Mobley

Masters Theses

"A Fermi neutron chopper and control system has been constructed and put into operation at the end of the UMR Reactor thermal column.

The operation of the chopper has been demonstrated by reproducing the slow neutron cross section data for aluminum and by measuring the previously undetermined slow cross section of cobalt.

The chopper which is powered by a series DC motor consists of 34 cadmium plated stainless steel blades separated by 1/16 inch aluminum spacers. The design incorporates the better characteristics of the Brookhaven and Argonne slow choppers. Speed regulation is accomplished using a silicon controlled rectifier feed back …

Plastic Design Of Steel Frames For Minimum Weight, I-Chen Hung

Masters Theses

"The purpose of this study was to develop a method for weight minimization of the plastically designed frame, braced normal to its plane of action, and composed of prismatic steel members. The method accounts for the non-linear relationship between weight and moment capacity for both beams and columns. Reduction in the pure-bending fully-plastic moment in the presence of axial loading and both beam-column instability and overall frame instability due to sidesway are taken into account. Provision is made for minimization of frames employing standard sections as well as for frames whose built-up members may be chosen from a continuous spectrum. …

Minimum Cost Data Collection Techniques For Circulation Control At The University Of Missouri At Rolla Library, John Peter Shewchuk Sr.

Masters Theses

"Data collection is beginning to assume increased importance in the field of data processing. This thesis investigates a method for quantitatively selecting a portion of the library to place on an automated circulation control system that uses data collection as an entry into a data processing system.

The circulation function of the library was considered to be an inventory problem. Titles were considered as items of inventory and circulation of that title was considered to be a "sale" of that item. The IMPACT method was used to distribute items (titles) in a sample by age. Various ages were found to …

The Effect Of Moisture On The Compressive And Tensile Strength On A Variety Of Rock Materials, Richard A. Martin

Masters Theses

"The effect of moisture on the strength characteristics of rock materials has been neglected in the study of rock mechanics. This study was undertaken to determine if there was any effect on the compressive and the tensile strength of rock by varying the moisture content from an oven-dried to a saturated condition.
It was found, by testing eight different rock materials that the compressive strength per unit area decreased with an increasing moisture content. The tensile strengths per unit area, with the exception of the quartzite and the porphyry samples, also decreased with an increase in moisture content. The tensile …

A Study Of Modified Plug Designs For A Globe Valve, Robert W. Wagner

Masters Theses

"This thesis presents an empirical study of the characteristics of a cylindrical skirted disk valve used as a flow regulating device. Holes were drilled in two separate removable cylinders, which, when respectively attached to the valve plug adapter, provided control of the flow rate. These cylinders could be moved to permit exposure of more or less flow area by means of the valve stem and crank mechanism. At the closed position of the valve no holes were available for flow within the differential pressure zone of the valve, while at the full-open position all the drilled holes were within the …

Permeability And Additive Sorption And Extraction In Lubricating Greases, Hsiu-Hsiung Lin

Masters Theses

"An important goal in the study of lubricating greases is the determination of the mechanism of additive action in lubricating greases and the effect of additive concentration on the improvement of particular properties. As a step in this direction, one aim of this investigation was an attempt to determine whether grease additives are sorbed on the thickener surface, or are dissolved in the oil phase, or if a combination of these effects prevails. Exploratory sorption and extraction experiments were run by Tu using greases thickened with lithium hydroxystearate and Baragel and using only one concentration of additive. More detailed studies …

The Development Of A Modified Soil Shear Vane, Vernelle Truman Smith

Masters Theses

"The purpose of this investigation was to determine how the soil shear graph could be modified to measure more accurately values of shear strength of fine-grained, cohesive soils. Several modifications were tried, however, the one that gave the most satisfactory results consisted of a vane and base plate mechanism.

A red clay of high plasticity obtained from a local cave was tested in both the natural or undisturbed state and in the remolded state. The only variable was the moisture content. Compaction effort was the same for all remolded specimens. Tests were conducted on undisturbed samples taken with thin walled …

The Shrinkage Characteristics Of Plastic Clay, Edward De Santis

Masters Theses

"This investigation was conducted to determine the shrinkage properties of a clay soil whose structure had been artificially altered in the laboratory. Various percentages of dispersing and flocculating agent were added to the soil and the shrinkage curves plotted.

The shrinkage curves of the chemically treated soil were compared with those of the untreated soil. The values of the theoretical and observed shrinkage limits were also compared to determine the validity of the standard shrinkage limit test which, at present, does not take into consideration the structure of the soil.

An explanation of the differences in the shrinkage characteristics of …

An Investigation Of Consolidation On Compacted Partially Saturated Clarksville Soil, Ma-Tai Matthew Chen

Masters Theses

"The Terzaghi theory of consolidation and the assumption of his theory, pore pressure and effective stress, secondary compression and rheology were all reviewed and discussed. Eight compacted unsaturated samples made from Clarksville silty clay (CL) under different compaction efforts and moisture contents were subjected to consolidation load increments. Each load increment was maintained for 24 hours. An extra compacted sample was loaded for one month to investigate secondary compression.

From e-p curves, five settlement vs. compacted embankment height curves were derived for different compaction effort and moisture contents. These curves may be of practical use, when checked by field measurements …

The Development Of The Sonic Pulse Technique And Its Comparison With The Conventional Static Method For Determining The Elastic Moduli Of Rock, James Harold Deatherage

Masters Theses

"The determination of the elastic moduli of rock has long been a problem to the geophysicist, mining engineer and the civil engineer. There is a considerable amount of literature on determining Young's modulus by the sonic pulse technique. However, the use of this technique to determine the three elastic constants, Young's modulus, shear modulus, and Poisson's ratio from measurements of both the longitudinal and shear wave velocities presents some difficulties, especially in the method of accurately determining the shear wave velocities.

In this thesis, what is believed to be a new method of measuring shear wave velocities in the laboratory …

Decarboxylation Of Malonic Acid In Aqueous Solutions, Ramesh Natwarlal Gujarathi

Masters Theses

"The rate of decarboxylation of malonic acid in aqueous solutions was studied over a range of concentrations, pH's, and temperatures. The catalytic effect of various divalent metallic ions was also studied at a pH of 0.3. these studies did not support a truly unimolecular decomposition as the experimental order was found to be slightly greater than one. An empirical relation for the rate of decarboxylation was formulated in which the undissociated malonic acid and the monovalent malonate ion were the reactive species.

A possible mechanism of decarboxylation due to solvent activation was postulated. No pronounced catalytic effect due to the …

An Ac Method Of Measuring The Conductivity Of Dielectric Liquids., Henry E. Fischer

Masters Theses

"The problem undertaken in this thesis is the presentation of a method of measuring the conductivity of dielectric liquids in which the liquid is used as the parallel tank circuit of a modified Wien-bridge oscillator. The main advantage of this method is that the frequency of the voltage applied to the liquid can be varied by simply varying the oscillator frequency. This allows the selection of a frequency which is best suited to the liquid in regard to polarization and relaxation time.

An oscillator was designed, built and used in the laboratory to measure the conductivity of the dielectric liquids …

Space-Charge Effects As Determined By Initial-Field Conditions, Tsing-Yih Wang

Masters Theses

"A method for calculating the current density passing between two parallel plane electrodes for different values of positive charges as a function of " field at the emitter to field for no charge ratio " is presented.
The problem of the potential distribution between the electrodes has been solved for one particular case in which the positive charges are assumed to be proportional to the field at the emitter. The expressions for the electric field, the velocity of charges, and the charge density as a function of the potential are also presented and plotted as a function of the distance. …

The Effect Of Structure On The Consolidation Characteristics Of A Clay Soil, Dale E. Sukow

Masters Theses

"This paper reports the results of an investigation conducted to establish the effect of structure on the consolidation characteristics of a clay soil. Soil structure was caused to form in the soil by the addition of electrolytes to flocculate and disperse the clay fraction of the soil.

Consolidation tests were performed on specimens of the treated soil prepared at moisture contents well above the liquid limit of the soil. The consolidation data from these tests are evaluated and comparisons are made to relate the influence of structure to the consolidation characteristics of the treated soil.

The influence of structure on …

A Study Of Shear Failures In Footing, Fred V. Cole

Masters Theses

"The purpose of this investigation was to conduct a model study of the basic mechanism of failure in shear of reinforced concrete footings through the use of plaster models.

Sixty-nine models were constructed and loaded to failure on a foundation of sand using various combinations of size and depth of model and column size. Load - deformation data and failure loads were recorded.

It was determined that model studies are a feasible procedure to analyse the mechanism of failure in footings. The perimeter of the loaded area was found to be the critical section in determining the ultimate shearing strength …

An Application Of The Variable Gradient Method Of Generating Liapunov Functions To Discrete Systems, Henry N. Peterson

Masters Theses

"The variable gradient method of generating Liapunov functions has been used only for continuous systems. This thesis presents an application of the variable gradient method to non-linear sampled data control systems.
Certain modifications to the variable gradient method are developed and several examples are presented which demonstrate the application. An attempt was made to synthesize the control system parameters, but due to the complexity of the ΔV functions, the synthesis in general cannot easily be obtained . To circumvent the problem of determining if the ΔV functions are negative definite, a set of computer programs were written to determine a …

A Study Of Molecular Diffusion In Polymer Solutions By A Microinterferometric Method, Girish T. Dalal

Masters Theses

"A microinterferometric method was used to study the effect of solute concentration on the diffusion coefficient in polymer solutions and also to determine the effect of polymer concentration on the diffusion coefficient. The polyacrylonitrile-dimethylformamide system was used as a means of determining the accuracy of the experimental apparatus and procedure. The non-ionic, water soluble polymer, hydroxyethyl cellulose (commercially known as Natrosol), was used to study this effect with urea and D-glucose as the solutes.

The results obtained for the polyacrylonitrile-dimethylformamide system were in close agreement with the results obtained by Secor, which meant that the experimental technique is accurate enough …

Analog Simulation Of The Voigt Solid, Richard F. Pohl

Masters Theses

"A method of reducing a mixed partial differential equation with boundary conditions to a form suitable for programming on the analog computer is developed. Presented along with the computer program set up to be used on the EAI TR-48 analog computer is a systematic check procedure to indicate possible computer malfunctions and programming errors. The results of the computer simulation are presented and supported with observed data"--Abstract, page ii.

Location Of Maximum Moments In A Continuous Two Span Beam Due To Moving Loads, Thomas Houng-Yn Yang

Masters Theses

"The objective of this investigation is to determine the positioning of vehicle wheels so as to cause maximum positive and negative moments in a two span continuous girder. Several variables are considered, namely, the ratio of loads to each other, the distance between wheels, and ratio of one span length to the other. The necessary equations are derived and the results, after being programmed on a computer, are shown in a series of curves.

These curves serve as a tool for the designer, enabling him to arrive at design moments by simple substitution in the appropriate moment expression, within the …

A Study Of The Effect Of A Square Cutout On The Moment Distribution In A Simply Supported Rectangular Plate Under Normal Concentrated Load By The Moiré Fringe Method, Taher F. Raja

Masters Theses

"Plexiglass models were used to produce Moiré fringes for two different geometrical shapes. The moments in the case of a simply supported rectangular plate with a normal concentrated load were found using the Moiré fringes which directly give the gradients at all points of the surface of the model. The variation of the moments due to a square cutout was also studied by this method. As a check for the experimental method, the analytical solution was presented for the plate without a cut-out. The Moiré method yields moments to an accuracy of 3 to 15 percent, however, care must be …

A Method For Approximating A Specified Impulsive Response, Charles A. Gross

Masters Theses

"Given a system's time response, y(t), to a unit impulse, a method is presented by which an approximating function y*(t) may be determined. It is inherent in the method that the transform function Y*(s) is rational. The poles of the approximating function are found from the coefficients of a difference equation, which is made to fit the given data in a least mean square error sense. The zeros are determined by a procedure based on the fact that at a given time the given function and its approximate derivatives are known. Accuracy and implementation of the method are investigated primarily …

Phase And Amplitude Distributions Of An Unsymmetrically Fed Ground Plane Aperture, Leslie Blumberg

Masters Theses

"An anechoic chamber for use in the B-12 KHz range was designed and built for the purpose of obtaining the far field patterns of antennas and radiation systems. This chamber was evaluated and compared with various types of anechoic chambers from the standpoint of their "room performance."

The anechoic chamber is essentially a room lined with absorbing material, effective at microwave frequencies. The purpose of the absorbing material within the room is to present the reflection of the energy incident upon the walls of the room.

Measurements of the far field radiation pattern of an aperture in a ground plane, …

The Effect Of Combined Torsional And Bending Loads On A Channel Beam With One End Restrained From Warping, David M. Schaeffer

Masters Theses

"Channel beams have been designed with the main purpose of giving large resistance to bending while the torsional strengths are known to be relatively small. In this experiment, a cantilevered channel beam was loaded with a concentrated load at the free end, first through the experimentally determined shear center and then through the centroid of the cross section. For each loading condition, the strains were measured with the aid of SR-4 strain gages placed at intervals along the length of the beam. With the aid of a computer, the strains were converted into longitudinal stresses and these stresses were compared …

The Effect Of Non-Linearity On A Frequency-Modulated Wave, Tzu-Tien Hung

Masters Theses

"A method is presented for finding the effect of a nonlinear characteristic of a device on a wave which is frequency modulated by only one sinusoidal modulating wave. The distortion in the output has been found by passing a frequency-modulated wave (which is represented by a summation expression for the spectrum components) through a non-linear circuit having a Fourier series represention of its Characteristic. Two cases have been considered: (1) a nonlinear output-input characteristic, and (2) a non-linear amplitude-frequency characteristic"--Abstract, page ii.

The Anodic Oxidation Of Maleic Acid, Larry D. Gilmartin

Masters Theses

"The purpose of this investigation was to determine the mechanism of the anodic oxidation of maleic acid on platinized-platinum electrodes at 80⁰C. Current density-potential studies were conducted varying the parameters of maleic acid concentration and pH. The faradaic efficiency of the oxidation of maleic acid to yield CO₂ was determined. The effect of temperature on current density was also studied to determine the activation energy for the reaction. The oxidation of maleic acid occurred only in acidic solutions. The faradaic efficiency was found to be approximately 97 ± 5 per cent. A linear Tafel region was found which had a …

Analysis Of Sand Asphalt Mixtures, Maurice A. Sayegh

Masters Theses

"The objective or this investigation was to determine the optimum percent of asphalt which should be added to the sand asphalt mixture. Also the effects of filler on the properties or the sand-asphalt mixture were evaluated.

The variables in this study were mineral filler, asphalt cement, and asphalt content. The sand used in this study was sub-rounded, and uniformly graded. The asphalt was asphalt cement with two different penetrations, one of 85-100 penetration grade and the other of 120-150 penetration grade.

Three different groups of mixtures of sand-asphalt were prepared. The first group consisted of adding 85-100 penetration asphalt to …

Anodic Dissolution Of Silver In Aqueous Solutions, B. W. Jong

Masters Theses

"The purpose of this investigation was to study the anodic dissolution of silver in various electrolytes to determine if there existed any deviations from Faraday’s law in nitric acid-silver nitrate solutions. The effect of small additions (10^-4 and 10^-5 N) of Cl^-, SO₄⁼, and CrO₄⁼ on the apparent valence and dissolution potential was also studied. Current densities were varied from 0.00 to 0.07 amp·cm^-2.

Based on the observed apparent valences and a grey film containing metallic particles on the anode surface, it was concluded that deviations from Faraday’s law …