Engineering Commons^™

Interactions Between Selected Pigment Producing Bacteria Isolated From Sewage, Leslie Alexander Lakie

Masters Theses

"Pigmented bacteria have been of interest to the microbiologist for several years. The pigmented organisms in sewage have been known to gain predominance, but no investigations have been made to determine whether the pigment assists the organism in gaining predominance. During this study a number of bacteria which produced a water soluble pigment were isolated from sewage. These bacteria were grown in shaken flasks using tryptone Glucose extract broth as a medium. Growth studies of the bacteria in pure and mixed culture were performed to determine if the pigment could affect another bacteria's growth. Studies were also performed using the …

A Laboratory Study Of The Transmission Of Signals Through Solid Material With Possible Application To Seismic Communication, Ronald Willis Carter

Masters Theses

"The problem of transmitting acoustic signals through solid material channels is investigated using piezoelectric transducers for generation and detection of the signals. Laboratory experiments are performed in which a solid material channel is modeled by a block of Berea sandstone. The magnitude of the frequency response for the sandstone and transducer combination is obtained over the frequency range of approximately 0 Hz to 500 kHz. Various electrical waveforms are utilized as driving sources for the transmitting transducer. It is found that the best received waveform is obtained when a gated sinewave whose frequency is approximately equal to the resonant frequency …

The Influence Of Member Length On Thermal Contact Resistance In A Vacuum Environment, Larry Martin Cooper

Masters Theses

"An investigation was conducted to determine the influence of member length on thermal contact resistance in a vacuum environment. A model was created which consisted of a center rod axially loaded between two other members. It was assumed that circular macroscopic constriction areas were formed at the contact interface when the rods were loaded. Macroscopic modeling of the contact surfaces makes the thermal contact analysis a function of the mechanical and thermal boundary conditions of the total body. The method of finite differences was employed to calculate the temperature distribution, heat flows, and thermal contact resistance of each member. Data …

Shear Properties Of An Organic Soil And The Same Soil With The Organic Matter Removed, David Eugene Daniels

Masters Theses

"The effect of strain rate on the shearing properties of an organic A̲ horizon Bryce clay and the same soil treated with hydrogen peroxide to remove the organic matter was studied. For both soils, the pore pressures were found to be independent of strain rate, and dependent only on the increment of strain during shear. The effect of the hydrogen peroxide treatment on the shear properties of an inorganic Bryce B̲ horizon clay was also studied. It was concluded that the hydrogen peroxide does not affect the mineral properties of the Bryce clay and serves only to selectively remove organic …

Phase Equilibrium And Thermodynamic Study Of The Iron-Copper-Carbon System, Krishna Parameswaran

Masters Theses

"Gas carburization experiments were conducted at 950ºC in order to study the phase relations and to determine the activity of carbon in the iron-rich corner of the iron-copper-carbon system. The solubility of graphite in equilibrium with iron-copper alloys was determined at 950º, 1000º, and 1050ºC. The results of gas carburization and graphite solubility experiments at 950ºC were used in constructing an isothermal section of the iron-rich end of the iron-copper-carbon phase diagram, on which are superimposed carbon isoactivity lines. Graphite solubility data at 1000º and 1050ºC were used to construct similar diagrams without the isoactivity lines. The effect of carbon …

A Hybrid Computer Solution Of The Swing Equation, Donald Wayne Shaw

Masters Theses

"Models for the governor and exciter control systems are presented and the development of a hybrid computing system including these models is described. A technique for including the governor and exciter effects into the solution of the power system swing equation is also discussed. A hybrid computing system consisting of an SCC 650 digital computer, hybrid interface, and an EAI-TR-48 analog computer is used to study five test cases. The test cases involve basically the same example system with different values for fault clearing times and machine inertias. The results of each test case are briefly discussed with relevance to …

The Concept And Design Of A Curvilinear Character Generator For Cathode Ray Tube Display Systems, Lawrence Edward Hanebrink Jr.

Masters Theses

"The character generator is the heart of any cathode ray tube display system. The types of generators in common use are the dot matrix generator, the raster scan generator, and the linear stroke generator. Each of these generators produces symbols whose legibility is somewhat compromised. A curvilinear generator is suggested which provides improved appearance and greater legibility. A prototype unit was constructed and the results are compared with the other generators. The curvilinear generator provides the best character resolution and readability of the generator types discussed"--Abstract, page ii.

Advanced Waste Treatment Of Industrial Waste Waters By Physicochemical Processes, Michael Gay Hardie

Masters Theses

"The primary objective of this investigation was to determine the general applicability of using physicochemical processes for treating different types of industrial wastes. Emphasis was placed on the evaluation of the treatment efficiency and the performance difficulties encountered in the treatment of each waste. Two types of waste were studied, one a high strength acidic industrial chemical waste and the other a petroleum refinery waste. The physicochemical system utilized included chemical coagulation and clarification plus activated carbon adsorption. Parallel operations of fixed-bed and expanded-bed carbon adsorbers were conducted. Treatment efficiencies were evaluated in terms of the removals of chemical oxygen …

The Skid Resistance Of Asphaltic Pavements Using Glass Aggregates, Michael Vaughn Korth

Masters Theses

"The disposal of the glass portion of solid waste is an ever-growing problem in the U.S. and recycling has been suggested as a possible solution. In order to find new uses for waste glass, investigations have been conducted to determine if the glass could be used as an aggregate in bituminous concrete mixtures. As part of the overall investigation, this study was concerned with investigating the skid resistance properties of the glass aggregate mixtures, called glasphalt. The objectives were to compare the skid resistance of various bituminous mixtures using aggregate combinations ranging from all glass to all conventional aggregate and …

An Investigation Of A Bistable Oscillator Used In A Phase Modulated Control Circuit, Yu-Fang Yen

Masters Theses

"A primary component in the investigation of phase modulated control systems is bistable oscillator which converts a constant oscillation signal to control the system. The oscillator is feedback type that utilizes a feedback capacitance and resistance in each feedback path to change its frequency. The theoretical behavior of bistable oscillator was investigated and the non-dimensional results were set for convenience in determining the oscillation period. The control circuit which based on the oscillator was also presented a form of suitable circuit for direct application to practical control problems"--Abstract, page ii.

High Temperature Compressive Creep In Mullite, Peter C. Smith

Masters Theses

"Compressive creep measurements were made on two groups of mullites at temperatures between 1455ºC and 1520ºC. The first group consisted of commercially manufactured mullites. The second group was made up of 7 different mullite compositions spanning the alumina-silica solid solution range from 3Al₂O₃ • 2SiO₂ to 2Al₂O₃ • SiO₂ . Thermal activation energies and stress exponents were calculated for the mullites in the second group. Steady state strain rates taken at 1460ºC under loads of 100 and 110 psi varied between 1.3x10⁻⁴ in/in/hr and 15.4x10⁻⁴ in/in/hr. Activation energies were between 109 Kcal/mole and 204 Kcal/mole. Stress exponents calculated from data …

A Software System For Interactive Man-Machine Design And Analysis Of Electronic Circuits, Leo William Midden

Masters Theses

"The development of an interactive computer-aided circuit analysis program is presented. A graphics terminal is used as an I/O device while an SCC 650 mini-computer is used as peripheral processor. The central processor is an IBM 360/50.

Formulation, capabilities and use of the system are discussed in detail. Close attention is given to user control, making the system both useful and versatile. Both hard and soft copies of all plots and tabular data are available. Provisions are made for error corrections and changes at each step of the input. Parameter values can be altered before and after each analysis.

Additionally, …

Mechanical Properties Of Low Carbon Martensite, Allen L. Affolter

Masters Theses

"Steels of three different compositions were heat treated and tensile tested in order to determine their mechanical properties after heat treatment. All samples had near 0.20 per cent carbon and two manganese levels 0.90 per cent and 1.35 per cent. One group containing the higher manganese level also had small additions of columbium and vanadium. The specimens were too brittle in the as-quenched condition to be loaded to full strength. Maximum strength and ductility were found after short time tempering at low tempering temperatures -- 2 to 15 minutes at 200º to 300ºF. Higher strengths were found at the low …

Practical Application Of Digital Computer To Distribution Systems, Juan Vincente Saavedra

Masters Theses

"Given a three phase ac power distribution system, a digital computer program is presented which determines a complete steady state solution for a given condition. The network data is processed by the computer into an admittance matrix, and these parameters are stored in a manner that enables the computer program to operate upon them as the coefficient of a simultaneous set of nonlinear equations. This set of equations are solved by the Gauss-Seidel Iterative Process improved by a modification of the relaxation method. Practical experience with the distribution system of the Davenport, Iowa, plant of the Aluminum Company of America …

The Artificial Sedimentation Of Soil, John Richard Wagner

Masters Theses

"Previous investigations concerned with artificially sedimented soils and a review of the literature on soil structure are summarized. These studies show that many of the physical properties of a soil depend upon its structure and that the structure of a sedimented soil depends principally upon the salt content of the pore water. In addition, artificially sedimented soils have been shown to have a "natural" soil structure. An apparatus was developed which will automatically sediment soils in water of controlled salt content. To determine whether or not the apparatus was able to sediment uniform and homogeneous soil samples, moisture content determinations, …

Low-Energy Electron Transport By The Method Of Discrete Ordinates, David E. Bartine

Doctoral Dissertations

"The one-dimensional discrete ordinates code ANISN has been adapted to simulate the transport of low-energy (on the order of a few MeV) electrons. Two different calculational techniques have been utilized for the treatment of electron-electron collisions that result in a small energy transfer. One method treats such collisions by a continuous slowing-down approximation, while the other method treats these collisions by the use of a very approximate cross section. Calculated results obtained with ANISN are compared with experimental data for the transmitted energy and angular distributions for 1-, 2.5-, 4-, and 8- MeV electrons normally incident on aluminum slabs of …

Internal Friction Of Ion Exchanged Li₂O•Al₂O₃•2sio₂ Glasses, A. Ismail A. Abdel-Latif

Doctoral Dissertations

"Li₂O•Al₂O₂•2SiO₂ glass fibers were ion-exchanged from 1 to 300 minutes in a sodium nitrate bath at 366ºC. The internal friction was measured along with the lithium and sodium concentration profiles. As sodium progressively replaced lithium, the alkali internal friction peak became smaller while a new peak (mixed alkali peak) appeared and increased in magnitude. These changes in the internal friction are similar to those that occur upon the addition of a second alkali to glasses prepared by conventional melting. The magnitude of both internal friction peaks in ion exchanged glasses was dependent on the overall glass composition. The magnitude of …

Identification Of Linear Systems With Delay Via A Learning Model, Hugh Francis Spence

Doctoral Dissertations

"The effects of input delay on an identification scheme using a learning model are investigated. The parameter adjustment laws for the learning model are derived through Lyapunov methods similar to those used for the model reference adaptive control systems of Parks. For no measurement noise or delay mismatch between the learning model and system, the parameters are adjusted to bring the error between model and plant to zero. When there is delay mismatch between the inputs of the learning model and the unknown system, the convergence of the parameters of the learning model to those of the unknown system is …

Dynamic Behavior Of Eccentrically Stiffened Plates, Charles Stuart Ferrell

Doctoral Dissertations

"The dynamic behavior of eccentrically stiffened rectangular plates is studied by the finite element method. The addition of stiffeners to a plate structure is a common method of increasing the rigidity of the structure with a minimum of weight increase. However, this stiffened plate configuration does not easily lend itself to analysis. This study is an approach to finding a rational method by which the dynamic behavior of such a stiffened plate structure may be determined. The governing differential equations for the finite element model are derived and the stiffness and mass matrices for the plate and stiffener elements are …

A Study Of Early-Late Type S0-Pcm Signal Bit Synchronizers, Kuang-Cheng Hu

Masters Theses

"The steady-state phase noise performances of an absolute value type and a squaring loop type of early-late gate S0-PCM signal bit synchronizers are developed using the Fokker-Planck method. The results are compared on the basis of the performance of two configurations with equal loop bandwidth at each input signal-to-noise ratio R_s. The probabilities of bit-detection error of the two configurations are compared. These comparisons are made as a function of R_s. The absolute value type of early-late gate S0-PCM signal bit synchronizater yields better performance than that of the squaring loop type of early-late gate S0-PCM …

Reservoir Design: Simulation Techniques, Larry W. Mays

Masters Theses

"A simulation model is developed to aid in the analysis of small dams to reduce the possibility of inadequate spillway designs. Basic assumptions concerning the geometric aspects of the natural reservoir are made to develop the model which is based upon describing the timing and magnitude of a design flood passing through a reservoir. Simulation equations are derived from the basic continuity equation and describe reservoir outflow and storage as functions of reservoir depth. Newton's Iteration Technique is utilized to solve the simulation equations for the reservoir depth. The resulting simulation model determines an optimum size auxiliary spillway having a …

An Energy Solution For Vibration Characteristics Of Free Thin Cylinders, Dale Elmer Leanhardt

Masters Theses

"In this report the flexural vibrations of the walls of free, thin, circular cylinders are considered. Theoretical expressions are developed for the natural frequencies by extending the approximate energy method of Arnold and Warburton to the free-free case. Furthermore, the developed expressions are shown to apply, as special cases, to the fixed-fixed and simply-supported cylinders analyzed by Arnold and Warburton. The energy solution for free-free cylinders is checked both experimentally using a 3500 pound-force, 5 to 2000 hertz, vibration exciter and numerically using the well documented SABOR IV-DYNAL finite element program. While the derived energy method accounts for any prescribed …

Calculation Of Eddy Current Loss Of A Disc, Kou Quen Chang

Masters Theses

"A method is presented to calculate the eddy current losses of a uniform disc with an opening in the center and excited by a circular current loopage First, the disc is subdivided into smaller concentric rings, then the self-inductances, the mutual inductances between these smaller rings, the mutual inductances between the excitation coil and the smaller rings, and the resistance of the rings are calculated. Next, the eddy current flowing in each ring is obtained by solving a complex matrix equation of the form [X] [I] = [V] where X is the impedance matrix, I is the eddy current matrix, …

Factors Affecting The Ductility And Microstructure Of Ti-6al-6v-2sn Titanium Alloy Weldments, Michael John Ball

Masters Theses

"The purpose of the investigation was to study the effect of material thickness, weld heat input and post weld heat treatment on the tensile properties and microstructure of Ti-6Al-6V-2Sn Titanium, and obtain a practical weld/thermal treatment cycle. The objectives were accomplished by electron beam and gas tungsten arc welding 0.060, 0.125 and 0.250 inch thick material and then heat treating at various temperatures and times. Electron beam and gas tungsten arc welding enabled an approximate 4:1 ratio of heat inputs to be utilized. Resultant welded and heat treated material was tensile tested and metallographically examined. Heat treatments involved both air …

Radiant Interchange In A Non-Isothermal Rectangular Cavity, Tilak Raj Sawheny

Masters Theses

"Radiant interchange between non-isothermal, gray diffuse surfaces with non-uniform radiosity has been determined for a rectangular cavity. Temperature distribution and heat flux as thermal specifications for the parallel surfaces of the cavity have been considered separately. Ambarzumian's method has been used for the first time to solve a radiant interchange problem. According to the method, the integral equation for the radiosity is first transformed into an integro-differential equation and then into a system of ordinary differential equations. Initial conditions required to solve the differential equations are the H-functions. The H-functions represent the radiosity at the edge of the cavity for …

A Step-Wise Gray Approximation Of The Radiative Absorption Coefficient For An Isothermal Hydrogen Plasma, Keith Harlan Browne

Masters Theses

"The radiative absorption coefficient of an isothermal hydrogen plasma is calculated using a step-wise gray approximation. The approximation retains a high degree of accuracy while significantly reducing the numerical computer time. The accuracy of the approximation depends on the spacing of the steps taken in the frequency spectrum as well as the number or steps used; 135 steps are used in this study. Plasma conditions of interest in this study are for temperatures between 5000 and 60,000ºK, densities between 10⁻⁵ and 10⁻⁷ gm/cm³, and thicknesses between 0.1 and 100 cm. Flux and intensity calculations are made for each case using …

Low Frequency Lumped Element Directional Couplers, Constantine Rodolph Jenkins

Masters Theses

"Lumped element directional couplers are desirable at frequencies below the VHF range because they eliminate the large physical size necessary for the distributed element directional couplers. The purpose of this work is to describe the theory and design of such low frequency lumped element directional couplers. A model for the coupler is developed and the equations which describe it are derived. Scattering matrices for one and two section couplers are obtained. Computer solutions for three section couplers are presented. Experimental results for one, two, and three section couplers are presented and comparison with theory are made. Comparisons of theoretical and …

Activation Volumes Of Carbon Diffusion In F.C.C. Iron-Nickel Alloys, James Raymond Keiser

Doctoral Dissertations

"The disaccommodation technique was used to determine the activation volume of carbon diffusion, ΔV, in six fcc iron-nickel alloys. Measurements were made at temperatures ranging from 68ºC to 90ºC and pressures up to six kilobars on samples having a nickel content between 31 and 63 at. %. A maximum activation volume of 3.9 cm³/mole was found at 34 at. % nickel. The compositional dependence of ΔV is satisfactorily reproduced by a magnetic energy continuum model in which it is assumed that the activation free energy of diffusion is essentially ferromagnetic in origin "--Abstract, page iii.

Structure And Properties Of Silver Borate Glasses, Edward Nashed Boulos

Doctoral Dissertations

"Clear glasses form in the system Ag₂O-B₂O₃ up to about 35 mol.% (65 wt.%) Ag₂O. Infrared absorption, thermal expansion and density data indicated an analogy to the Na₂O-B₂O₃ system. Pentaborate-triborate group pairs appear to be formed upon the addition of Ag₂O to B₂O₃ up to 20 mol.% Ag₂O and diborate groups from 20 to 33 mol.% Ag₂O. This interpretation is supported by the comparison of the infrared absorption spectra of quenched and crystallized glasses. One crystallization product ,Ag₂O.4B₂O₃, has been identified previously. A new compound starts to appear at 28 mol.% Ag₂O. Silver is generally present as a network modifier …

A Computerized Decision Model For Making Quantitative Decisions With Regards To The Department Of Army's Equipment Improvement Recommendations, Lewis Neri

Masters Theses

"The management decision technique, currently in use, of determining priority of EIR evaluation is basically that of "feel and experience" along with the "most pressure" applied from outside the responsible organization. The feasibility of a computerized management decision concept has been studied at the lowest system with the objective of applying this to the next higher systems and finally arriving at an overall system value to obtain system priority. This study develops the technology of operations research and the associated computer techniques, delineates the problem and develops a mathematical model to simulate this management decision technique. Furthermore, it utilizes logical …