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Articles 73591 - 73620 of 77382

Full-Text Articles in Engineering

Final Sintering Of Cr₂O₃ With Minor Additions Of Mgo And Sintering Of Mgo With Minor Additions Of Cr₂O₃, Gordon E. Jungquist Jan 1971

Final Sintering Of Cr₂O₃ With Minor Additions Of Mgo And Sintering Of Mgo With Minor Additions Of Cr₂O₃, Gordon E. Jungquist

Masters Theses

"The effect of oxygen activity on the sintering of Cr₂O₃ with minor additions of MgO, and of MgO with minor additions of Cr₂O₃ at 1600ºC was investigated. A peak density (99.4% of theoretical) was obtained for high purity Cr₂O₃ by maintaining the equilibrium oxygen partial pressure needed to maintain the Cr₂O₃ phase. The addition of 0.1 wt. % MgO increased the sintered density at the same oxygen pressure to 99.8%. Further MgO additions decreased the density. The density of pure MgO was independent of the PO₂ over the range investigated. Addition of Cr₂O₃ to MgO decreased the density at …

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Alkali Mobility And Mechanical Relaxation In Mixed-Alkali Silicate Glasses, James W. Fleming Jr. Jan 1971

Alkali Mobility And Mechanical Relaxation In Mixed-Alkali Silicate Glasses, James W. Fleming Jr.

Masters Theses

"Internal friction and sodium and potassium self-diffusion coefficients for (1-X)Na₂O · XK₂O· 3SiO₂ glasses were measured. Alkali diffusion was measured between 300 and 500ºC using radioactive isotopes and a thin-sectioning technique. Internal friction was measured from room temperature to 500ºC, 0.1 to 2000 Hz. Comparison between alkali diffusion and internal friction data for Na-K glasses with those for other mixed-alkali glasses shows that the mixed-alkali peak is related to alkali mobility. It is concluded that the mechanism for mixed-alkali internal friction is a cooperative rearrangement of dissimilar alkali ions, with the slower moving ion controlling the rate of reorientation"--Abstract, page …

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A Study Of The Effects Of Mixing On The Accelerated Anaerobic Digestion Of Concentrated Municipal Sludges, Victor Darryl Orr Jan 1971

A Study Of The Effects Of Mixing On The Accelerated Anaerobic Digestion Of Concentrated Municipal Sludges, Victor Darryl Orr

Masters Theses

"Most domestic sewage treatment plants today practice anaerobic digestion of sludge. The purpose of this investigation was to determine if thorough mechanical mixing of concentrated sludge would improve its digestion. The simulated digesters consisted of six 1 gallon anaerobic reactors which were operated in the laboratory for 78 days. The contents of three digesters were continually mixed and their responses were compared with those of the similarly loaded remaining three unmixed units. Raw sludge with solids concentrations of 7.5, 15 and 30 per cent was digested for detention periods of 30, 15 and 7.5 days at 33º C. Various analyses …

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The Thermal Contact Resistance Of Lubricant Films In Vacuum, Garry A. Heizer Jan 1971

The Thermal Contact Resistance Of Lubricant Films In Vacuum, Garry A. Heizer

Masters Theses

"This paper presents the results of an experimental investigation on the thermal contact resistance of lubricant films and bare interfaces. The apparatus and procedure used in the determination of these resistances are described. Twelve series of tests were performed to evaluate the effects of temperature and contact pressure on the thermal resistance of lubricant films. Variations of thermal contact resistance with temperature and contact pressure for four lubricants and for bare interfaces are presented graphically. The thermal resistances of the four lubricants tested in vacuum conditions: lithium grease, graphite grease, molykote grease, and silicone lubricant, were found to lie in …

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The Effect Of Solvents On The Desorption Of Phenol From Carbon In A Water Free System, William W. Knickmeyer Jan 1971

The Effect Of Solvents On The Desorption Of Phenol From Carbon In A Water Free System, William W. Knickmeyer

Masters Theses

"The desorption of phenol from active carbon was studied using a continuous flow desorber. The system used was nearly water free to reduce water-phenol interactions. The ten solvents used in this study exhibited a wide difference in their desorption capabilities. An attempt to correlate the desorption data with the physical properties of phenol and solvents, in addition to regular solution theory, proved unsuccessful. A thermodynamic approach using the linear free energy-enthalpy relationship produced a general trend by using the heat of solution for phenol in solution and a reasonable correlation using the heat of formation of the phenol-solvent hydrogen bond …

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Anodic Oxidation Of Ethylenediaminetetraacetic Acid On Pt In Acid Sulfate Solutions, Howard Ho-Wei Jiang Jan 1971

Anodic Oxidation Of Ethylenediaminetetraacetic Acid On Pt In Acid Sulfate Solutions, Howard Ho-Wei Jiang

Masters Theses

"The anodic oxidation of EDTA was studied in acid sulfate solutions on platinized-Pt at 25ºC. Polarization relationships were obtained for the EDTA concentration range 3. 42 x 10⁻⁵ to 3. 42 x 10⁻³ M and pH range 0. 35 to 3. 80. Numerous reaction products were identified that indicated a sequential removal of acetate groups from the EDTA, each by an initial decarboxylation followed by a reverse Schiff-type reaction, that produced formaldehyde and the corresponding amine. A reaction sequence which correlated the experimental data involved Frumkin-type adsorption of the EDTA species through an unionized acetate group followed by a rate-determining …

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Electrolytic Reduction Of Zinc From Acidic Sulfate Solutions, Kenneth Dale Gielow Jan 1971

Electrolytic Reduction Of Zinc From Acidic Sulfate Solutions, Kenneth Dale Gielow

Masters Theses

"Cathode polarization curves were obtained for the electrodeposition of zinc from sulfate solutions with pH 2 and zinc concentrations of 10.0, 40.0, 80.0, and 100.0 gpl zinc. Both pure zinc and pure aluminum were used as cathodes with some difference in results noted. The effect of animal glue additions of 0.01, 0.10, and 0.50 gpl of solution on the cathodic polarization curves and the resulting deposit morphologies were determined. These glue additions correspond to 0.20, 2.0, and 10.0 pounds of glue per ton of zinc deposited, respectively. The slope of the Tafel region of the polarization curves was found to …

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A Study Of Radiative Heat Transfer From A Spherical Layer, Hakimuddin Kalimuddin Khalil Jan 1971

A Study Of Radiative Heat Transfer From A Spherical Layer, Hakimuddin Kalimuddin Khalil

Masters Theses

"The problem of radiative heat transfer from a spherical layer of absorbing-emitting gas has been studied. First, the medium is assumed to be gray and then nongray. A thorough survey of literature from fields other than heat transfer, such as astrophysics and neutron transport has been made to stimulate further interest in this important area. To gain some insight into the effect of various parameters on the heat transfer, simple physical situations involving isothermal medium are considered. Comparison of the results obtained for the flux from the spherical and planar layers reveal that the curvature becomes increasingly important as the …

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Hydrostatic Extrusion Of Tubular Products, John Lester Roth Jan 1971

Hydrostatic Extrusion Of Tubular Products, John Lester Roth

Masters Theses

"The production of quality tubular products by hydrostatic extrusion has been demonstrated to be a highly satisfactory method. The forming of tubes by the floating mandrel method has been accomplished on mild steel, aluminum alloy, and brass. This thesis describes the method, equipment design and operation, and the results obtained in the hydrostatic tube extrusion. A discussion on the advantages of the use of hydrostatic over conventional extrusion is included. The hydrostatic extrusion system designed for this study is described in detail"--Abstract, page ii.

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A Statistical Hydrologic Simulation Model, Ronald L. Wycoff Jan 1971

A Statistical Hydrologic Simulation Model, Ronald L. Wycoff

Masters Theses

"Simulation of a physical system requires knowledge of all components of the system and their interactions. A probabilistic simulation model of a hydrologic system is developed from short term continuous, sychronized rainfall-runoff records. The individual components of the system area the time between and duration of storms, the depth of rain occurring in each time period of the storm, precipitation excess relations, and the watersheds unit hydrograph. The available data is used to define or develop the probabilistic models involved. The only nonprobabilistic model employed is the watersheds unit hydrograph. It is found that the time between and duration of …

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A Study Of The Void-Strengthening Of Aluminum And Its Nature, Purushottam G. Manusmare Jan 1971

A Study Of The Void-Strengthening Of Aluminum And Its Nature, Purushottam G. Manusmare

Masters Theses

"Strengthening of aluminum by formation of the voids and the nature of resultant strengthening, viz., the temperature and the strain rate dependence of its yield strength were studied. Aluminum wires with 99.999% purity and of 3.1 mm diameter were quenched and heat treated to form voids of the approximate density 10¹³-10¹⁴ voids/cm³ and were tested for their yield strength. Voids in selected samples were observed by transmission electron microscopy using the Hitachi HU-11A microscope. The yield strength of the void strengthened samples was measured at various temperatures from 77ºK to 593ºK using two strain rates, 3.33 x 10⁻²/sec and 1.67 …

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Two Component Heat Pipe, Surapol Chandsawangbhuvana Jan 1971

Two Component Heat Pipe, Surapol Chandsawangbhuvana

Masters Theses

"A two component heat pipe with water and ethanol as the working fluid was investigated at different angles of inclination and various ethanol concentration for two power loads. The heat pipe was 15 inches long and 0.75 inches in diameter with a 100 mesh stainless steel screen wick. The wall and the vapor temperatures were measured at different stations along the length of the heat pipe by copper-constantan thermocouples. The results were used to evaluate an existing model which includes the constraint of thermodynamic phase equilibrium of the solution on the governing equations. Based on the measured pressure and temperature …

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The Use Of Scattering Parameters In Amplifier Design, Yousef Neman-Ebrahim Jan 1971

The Use Of Scattering Parameters In Amplifier Design, Yousef Neman-Ebrahim

Masters Theses

"The scattering-parameter formulation of an active two-port device is developed from the compensation theorem. The use of scattering parameters in graphical developments of forward operating power gain and tunability is considered in detail. Finally, two design examples show the application of the graphical procedures"--Abstract, page ii.

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Digested Sludge Dewatering On Drying Beds Under Controlled Environmental Conditions, Daniel James Harris Jan 1971

Digested Sludge Dewatering On Drying Beds Under Controlled Environmental Conditions, Daniel James Harris

Masters Theses

"The dewatering characteristics of anaerobically digested primary and activated sludge were investigated under eight selected combinations of laboratory controlled air temperature and relative humidity using three open, drained model beds, as well as a closed, drained and an open, nondrained bed. The evaporation rate from a free water surface was also determined. Moisture content, drainage, evaporative weight loss, and sludge surface recession were measured and recorded periodically throughout the two week period of each of the eight experiments. Relationships were shown to exist between sludge moisture content, evaporation rate from a free water surface, and the parameters 6T (the difference …

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Evaporation And Condensation Of Zinc, Shailesh Bhanuprasad Vora Jan 1971

Evaporation And Condensation Of Zinc, Shailesh Bhanuprasad Vora

Masters Theses

"Evaporation rates of liquid zinc were determined experimentally within the temperature range of 450º C to 575º C and at argon pressures ranging from 730mm Hg to 130mm Hg. Extrapolated values of these rates are found to be consistent with the previously reported rates obtained by St. Clair and Spendlove at lower pressures. Between 100 microns and one atmosphere pressure rates of evaporation seem to vary according to an equation of the form W = APᴮ, where Pis pressure and, A and B are constants. Similar experiments were performed with brass powders in atmospheres of argon and helium at temperatures …

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Simulation Of Digital Computer Simcom, Ming-Te Hsieh Jan 1971

Simulation Of Digital Computer Simcom, Ming-Te Hsieh

Masters Theses

"SIMCOM(SIMulated COMputer) is a hypothetical small general-purpose digital computer. It has a core memory of 4096 12-bit words and has been modeled after the Scientific Control Corporation SCC 650. The instructions of SIMCOM are completely compatible with the SCC 650, any SIMCOM program can be run on the SCC 650. The logical organization is similar but not identical to the SCC 650, the mnemonics that are used to represent all instructions are identical to those used on the SCC 650 except the Input/Output instructions. This computer can be simulated on any available commercial computer. If such a simulation is available, …

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Feed Drive Design For Numerically Controlled Machine Tools, Subash Bhatia Jan 1971

Feed Drive Design For Numerically Controlled Machine Tools, Subash Bhatia

Masters Theses

"The various types of feed drive control systems used in numerical control of machine tools have been broadly classified. Further a step by step design has been presented for the feed drive of a numerical contouring control milling machine. The aim has been to develop a consistent strategy for tackling a variety of such problems. Consequently stress has been laid on principles and not on design figures"--Abstract, page ii.

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Frequency Division Using Cascaded Phase-Locked Loops, Curtis B. Abshier Jan 1971

Frequency Division Using Cascaded Phase-Locked Loops, Curtis B. Abshier

Masters Theses

"In many practical communication systems it is necessary to generate phase coherent subharmonics of an input tone. A useful system for accomplishing this task is a system of phase-locked loops in cascade. It is shown that when the feed-forward function is matched, the phase error of the second loop is zero. Analytical analysis and computer simulation prove that the minimum time to achieve phase-lock is obtained when the feed-forward function is matched. Under this condition, necessary design parameters are determined with ease"--Abstract, page i.

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Design Of A Quadrature Envelope And Correlating Receiver, Clinton Harold Moor Jan 1971

Design Of A Quadrature Envelope And Correlating Receiver, Clinton Harold Moor

Masters Theses

"A receiver design analysis and rationale is presented. The receiver is capable of performing in an instrumentation role for propagation experiments conducted in the field. The data gathered during the field tests will be used to determine the complex impulse response of the ground-to-ground communications channel and to evaluate the performance of a candidate ranging waveform in this channel. The receiver is capable of operation in either the propagation mode or the ranging mode and each mode of operation can be performed on either a UHF band frequency or an L-Band frequency. During the propagation mode the receiver serves as …

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An Analysis Of Solar Noise Outbursts And Their Application To Space Communication, Marion Francis Moen Jan 1971

An Analysis Of Solar Noise Outbursts And Their Application To Space Communication, Marion Francis Moen

Masters Theses

"A relationship between sunspot activity, solar flare activity and noise outbursts is presented. Five different types of interference radiation in the 10MHz to 30,000 MHz frequency band are discussed. Data obtained by solar radio astronomy are analyzed to determine the extent of solar noise outbursts as a function of sunspot activity. An application of the burst data to future space communication is given"--Abstract, page ii.

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Variable-Threshold-Mixed-Weight Threshold Element, Cheng-Chung Liu Jan 1971

Variable-Threshold-Mixed-Weight Threshold Element, Cheng-Chung Liu

Masters Theses

"A threshold element (TE) is a mathematical model of a class of logic gates. The desirability of a threshold element in the application of digital systems stems from its richness of logic power and its relative economy. On the other hand, the tighter tolerences required by the threshold logic element as compared to conventional logic gates have prevented them from being utilized extensively. The purpose of this thesis is to propose a versatile threshold element having high noise immunity and loose tolerance requirement. The proposed TE which has variable threshold and mixed weight capability uses current switching to enhance noise …

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An Analog Computer Simulation Of The Flapping Of A Helicopter Hinged Main Rotor Blade, Edward Charles Robinson Jan 1971

An Analog Computer Simulation Of The Flapping Of A Helicopter Hinged Main Rotor Blade, Edward Charles Robinson

Masters Theses

"An analog computer simulation was performed on the Systron Donner SD 40/80 electronic differential analyzer consisting of one panel (SD 40) less three modules augmented by three digital logic modules for iterative operation. The flapping equation was solved in continuous iteration for various values of blade mass and the resultant blade flapping magnitudes and harmonic coefficients were compared in computer plots of the blade tip path plane. A flap compensator was added and the result plotted. Various aerodynamic parameters of the flapping equation solution were plotted"--Abstract, page ii.

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A Time And Frequency Domain Approach To The Optimization Of Linear Multivariable Regulators, Eugene Charles Machacek Jan 1971

A Time And Frequency Domain Approach To The Optimization Of Linear Multivariable Regulators, Eugene Charles Machacek

Masters Theses

"Optimal design and analysis of a multivariable regulator may be achieved in either the frequency or time domain. This paper describes the formulation of the matrix Riccati equation in the time domain and the Wiener-Hopf equation and the root-square-locus in the frequency domain. The necessary requirements which must be satisfied in order to achieve an optimal control vector when using a quadratic performance index are presented for both domains. The resultant optimal control vector is shown to be a linear function of the system state vector. The effect of the quadratic performance index weighting matrices on the optimal system closed-loop …

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A Closed Form Method For Predicting The History Of Circular Orbit Altitude Decay Of A Near-Earth Satellite Including The Effect Of A Dynamic Atmosphere, John Copley Buchholtz Jan 1971

A Closed Form Method For Predicting The History Of Circular Orbit Altitude Decay Of A Near-Earth Satellite Including The Effect Of A Dynamic Atmosphere, John Copley Buchholtz

Masters Theses

"A closed form expression for the time to decay between two circular orbit altitudes is developed. The long-term dynamic variation of high altitude atmospheric density is included. The density is approximated as a ratio of two quadratics with the numerator being a function of the time-related exospheric temperature and the denominator being a function of altitude. The 11-year cyclic variation of exospheric temperature is then represented as a piecewise linear function of time. The analytic expression for circular orbit altitude decay rate is developed by describing the energy loss due to atmospheric drag. A point mass representation of the Earth's …

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An Investigation Of Stress In The Monowall Construction System Subjected To Racking Loads, Louis Alex Kuhlmann Jan 1971

An Investigation Of Stress In The Monowall Construction System Subjected To Racking Loads, Louis Alex Kuhlmann

Masters Theses

"Several methods of analysis were employed to investigate the stress conditions of concrete block built in the MONOWALL Construction System, when subjected to racking loads. MONOWALL is a technique of assembling blocks with adhesive rather than conventional portland cement mortar. The analyses used in this study included strain gages on full-scale walls, photoelastic models, and a mathematical solution. Each method of analysis is reported separately in detail and the results compared to each other"--Abstract, page ii.

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Perturbation And Sensitivity Analysis Of An Urban Model, Nicola Ann Nelson Jan 1971

Perturbation And Sensitivity Analysis Of An Urban Model, Nicola Ann Nelson

Masters Theses

"This work describes a sensitivity analysis of the nine major system variables of the urban model postulated by Dr. Jay W. Forrester in his book Urban Dynamics. This model simulates the growth of a city from a nearly empty land area through a 250 year life cycle. Using small perturbations about the system trajectories, sensitivity matrices were computed at 135 years (growth period) and 240 years (equilibrium). The results show a matrix heavily weighted to give large sensitivity coefficients to the three housing variables, the PH sector being the most sensitive. Each of the housing sectors was analyzed further to …

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A Digital Computer Simulation Of A Rural Two-Lane Highway, D. Jay Frankenfield Jan 1971

A Digital Computer Simulation Of A Rural Two-Lane Highway, D. Jay Frankenfield

Masters Theses

"The traffic flow model developed in this study is a digital computer simulation utilizing the technique of periodic scanning to move the vehicles through a series of unit blocks. The model simulates traffic flow on a rural two-lane highway by assuming a straight and level road and incorporating sight distance restrictions and no-passing zones to simulate the effect of limited sight distance. By utilizing various "passing rules" to initiate the passing maneuver, three general topics were investigated. This study investigated the use of 1000 ADT as a criterion for yellow line striping no-passing by using the computer simulation to determine …

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A System Study Of A Computerized Grocery Store, Neal Joseph Martini Jan 1971

A System Study Of A Computerized Grocery Store, Neal Joseph Martini

Masters Theses

"This thesis is a system study of a computer controlled grocery store. Previous work has been done in the area of computerized inventory control, and computerized checkout lines in grocery stores, but the system proposed in this thesis is to control the movement and handling of the products as orders are automatically filled. In the preliminary part of the system study, a comparison between a time shared computer service and a minicomputer is done, which results in the selection of a minicomputer for this control system. Then the general control system is presented, and the system interfacing and control for …

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Compressibility Effects On Transient Gas Pipe Flow, Gerald Francis Mouser Jan 1971

Compressibility Effects On Transient Gas Pipe Flow, Gerald Francis Mouser

Masters Theses

"Abstract (1) Methods of iterative solution for the partial-differential equations that govern the transient flow of gases in pipelines are obtained by using the method of characteristics and linear finite-difference techniques. Solutions are developed for 1) a constant gas compressibility factor throughout transient conditions, and 2) a variable gas compressibility factor at constant temperature dependent upon pressures encountered during transient flow. Theoretical studies are made to compare results using both approaches for pipelines operating at various constant flowing temperatures. Results show greater differences between the two methods at lower values of flowing temperature due to the more rapidly changing compressibility …

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Laser Interferometric Holography Investigation Of Free Convection About A Vertical Plate Of Non-Uniform Temperature, Richard Kenneth Thomson Jan 1971

Laser Interferometric Holography Investigation Of Free Convection About A Vertical Plate Of Non-Uniform Temperature, Richard Kenneth Thomson

Masters Theses

"An experimental investigation was conducted using a holographic interferometer to detect the temperature variation in a free convection boundary layer about a vertical heated plate. The heated plate was non-isothermal and investigations were conducted for four temperature distributions; the maximum plate temperature ranged from 200F to 493F. Photographs were taken of the fringe patterns and boundary layer thickness measurements, as well as temperature measurements, were made. A theoretical model was constructed by applying the integral method to the energy and momentum equations. The experimental values agree quite well with this model. The advantages of the holographic interferometer over other systems …

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