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Articles 187261 - 187290 of 193465

Full-Text Articles in Engineering

The Effect Of Small Additions Of Niobium Upon The Corrosion Rates And Electrochemical Potentials Of Iron In Hcl, Hf, And H₂So₄, Richard Lee Jones Jan 1969

The Effect Of Small Additions Of Niobium Upon The Corrosion Rates And Electrochemical Potentials Of Iron In Hcl, Hf, And H₂So₄, Richard Lee Jones

Masters Theses

"The valence of niobium ions going into solution was determined by dissolving the metal in hot HF and measuring the volume of hydrogen evolved. The corrosion rates of Nb, NbHx, Fe and Fe - Nb alloys were determined in various concentrations of NCl, H₂SO₄ and HF. The Fe and Fe - Nb alloy samples were made by using powder metallurgy techniques. It was found that a metal skin was produced on the surface of iron corrosion samples if the carbon content of the surface layer was lower than that of the core of the sample. The lower carbon …

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Apparatus And Techniques For The Plane Wave Analysis Of Acoustic Filters, Victor Hugo Simon Jan 1969

Apparatus And Techniques For The Plane Wave Analysis Of Acoustic Filters, Victor Hugo Simon

Masters Theses

"This thesis describes a method for determining the reflection and transmission characteristics of acoustic filters under static (i.e. no flow) conditions. These characteristics are obtained by the combination of linear plane wave acoustic theory with a sequential experimental procedure. The experimental data necessary for the calculation of the reflection characteristics were obtained from measurements made on the inlet side of the filter with a standing wave tube apparatus. In order to calculate the transmission characteristics of the filter, the standing wave measurements were augmented with measurements taken on both the inlet and outlet side of the filter. This was accomplished …

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Investigation Of Free Convection Heat Transfer From An Inclined Flat Plate, Phairojna Sang-Urai Jan 1969

Investigation Of Free Convection Heat Transfer From An Inclined Flat Plate, Phairojna Sang-Urai

Masters Theses

"The experimental investigation was conducted to determine temperature distribution and convective heat transfer coefficients in terms of Nusselt number for an inclined heated flat plate in air. The heated surface of the aluminum flat plate was set facing upward and moved through seven positions from the vertical to the horizontal. The investigation shows that the local Nusselt number can be predicted by Kiekus's solution within 12 per cent for inclination angles from the vertical through 75° from the vertical. In the case of the vertical position, Eckert's solution gives a better prediction. For the horizontal position the results show good …

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Application Of Approximate Transmission Matrices To Describe Transverse Beam Vibrations, Ranjit Kumar Roy Jan 1969

Application Of Approximate Transmission Matrices To Describe Transverse Beam Vibrations, Ranjit Kumar Roy

Masters Theses

"This paper is a report of an investigation of an approximate method for finding the principal mode frequency roots for beams in transverse vibration. The method utilizes approximate transmission matrices obtained by a power series expansion of the basic differential equation which governs the transmission matrix. Investigation has been carried out to examine the efficiency of the method in producing the first several normal mode frequency roots. This has been achieved by applying the method to several uniform and non-uniform beams and comparing the results with the exact solutions. The technique has further been applied to non-uniform beams of tapered …

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Design, Construction, And Initial Experiments With High Hydrostatic Pressure Extrusion Device, Edward Moniz Jorge Jan 1969

Design, Construction, And Initial Experiments With High Hydrostatic Pressure Extrusion Device, Edward Moniz Jorge

Masters Theses

"The purpose of this study was to design and operate equipment with which the study of polymer extrusion would be possible at hydrostatic pressures up to 50,000 psi. By hydrostatic pressure is meant the pressure of the region of the extrudate. A study of the effects of back pressure on the extrusion of silicone gum was attempted--Abstract, Page ii.

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The Influence Of Several Factors On The Rate Of Secondary Compression Of Soil, William Joel Green Jan 1969

The Influence Of Several Factors On The Rate Of Secondary Compression Of Soil, William Joel Green

Masters Theses

"This research program has been undertaken to study the influence of load increment ratio, temperature, and sample thickness on Cα (rate of secondary consolidation) for a high organic content and low organic content soil. Consolidation equipment was designed to produce constant temperatures both above and below ambient, and to accommodate both 3/4 and 1 1/2 inch thick samples. Samples were molded into oedometer rings at the liquid limit. It was found that Cα was independent of the sample thickness and load increment ratio for both the high organic and low organic soils. The influence of temperature on Cα was found …

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A Study Of A Lead Mining Waste Water Pollution Problem, William Earl Anderson Jr. Jan 1969

A Study Of A Lead Mining Waste Water Pollution Problem, William Earl Anderson Jr.

Masters Theses

"The waste water from the Fletcher Mine of the St. Joseph Lead Company was producing large algal growths in Bee Fork Creek. A field and laboratory study was conducted to determine the characteristics of the waste, find a method of determining the pollutional materials contained in the waste, study the undesirable algal growths, and develop and evaluate a practical, inexpensive, and effective pollution abatement method. Laboratory studies included analytical analysis of the waste, flotation reagent analysis, a microscopic study of the algal growths, algal growth studies, and heavy metal analysis of the algal growths. Field work comprised: a study of …

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Analysis Of The Traveling-Wave Transistor, Vernon Ray Stanley Jan 1969

Analysis Of The Traveling-Wave Transistor, Vernon Ray Stanley

Doctoral Dissertations

"Transmission lines containing independent and dependent distributed sources are considered and the transfer matrices of various active distributed lines are derived. A method is discussed by which a lossy line can be made lossless by the appropriate choice of distributed sources. A steady-state analysis of the uniform traveling wave transistor is given. Considering the device as an active four port network, the transfer matrix is found in closed form and the power gain, output voltage, and input impedance are found. A computer program is written and the frequency response is given for various values of line parameters and terminations. Finally, …

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An Optimization Approach To Well Spacing For Gas Storage Reservoirs, Jagannath Rao Ghole Jan 1969

An Optimization Approach To Well Spacing For Gas Storage Reservoirs, Jagannath Rao Ghole

Doctoral Dissertations

"A finite approximation to the conventional diffusivity equation describing compressible fluid flow through porous media has been developed with a view to apply it to the problems of optimum well spacing. An equilateral grid system has been employed to enable uniform well spacing for any number of wells. A numerical model has been developed on an IBM 360 - Model 50 computer, which simulates the pressure and saturation transience in the reservoir due to production impulses. This model has been used to maximize with respect to number of wells, the minimum well bore pressure reached throughout the specified withdrawal schedule. …

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Grain Boundary Self-Diffusion In Sodium Chloride, Kenneth Ray Riggs Jan 1969

Grain Boundary Self-Diffusion In Sodium Chloride, Kenneth Ray Riggs

Doctoral Dissertations

"The diffusion of ²²sodium and ³⁶chlorine along tilt and twist grain boundaries in pure and calcium chloride doped sodium chloride bicrystals was investigated. No enhanced diffusion of ²²sodium along the grain boundaries was observed. Between 400°C and 500°C the chlorine grain boundary diffusion parameter, D'Δ, is described by D'Δ = (D'Δ)₀exp (-Qb/kT), where (D'Δ)₀ is approximately 10⁻⁷ cm³/sec and Qb is 1.15 ± .30 eV. The grain boundary angle, the grain boundary character (tilt or twist), and the calcium chloride concentration appear to have no pronounced effect upon the observed chlorine grain boundary diffusion. The ionic movement …

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Microwave Propagation Through Isotropic Inhomogeneous Photoconductive Media, Thomas Van Doren Jan 1969

Microwave Propagation Through Isotropic Inhomogeneous Photoconductive Media, Thomas Van Doren

Doctoral Dissertations

"The electromagnetic field equations for microwave propagation through a rectangular waveguide filled with a lossy, isotropic, linear, inhomogeneous material are derived in matrix form and solved numerically by computer. The theoretical effects of photo-induced conductivity and dielectric constant variations on microwave attenuation, phase shift, and voltage standing wave ratio are plotted for typical examples in the X-band frequency range. The theoretical calculations indicate that a two order-of-magnitude change in the conductivity can produce a 25 db change in the attenuation or a 100 degree change in the angle of the reflection coefficient. The theoretical predictions are verified qualitatively by experiments …

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Mass And Heat Transfer Through Nonwettable Porous Membranes, Chung-Liang Yeh Jan 1969

Mass And Heat Transfer Through Nonwettable Porous Membranes, Chung-Liang Yeh

Doctoral Dissertations

"Evaporation of water through nonwettable porous membranes has been studied under various pressures with various membrane thicknesses. The results of previous investigations at 1 atmosphere have been correlated into one equation for mass transfer resistance which has also been found to fit approximately new data obtained of 1.5, 2, and 3 atmospheres in this investigation. In the new data fluxes varied from 0.064 to 0.691 lb./ft.²/hr. through glass fiber-Teflon membrane from 0.02 to 0.08 inch in thickness. Temperatures ranged for 80 to 260°F. A more theoretical equation has been developed to explain variations from the equations based on 1 atmosphere …

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Models For The Pn Diode And The Npn And Pnp Transistor For Use In Computer Aided Design And Analysis Programs, Glenn Ronald Case Jan 1969

Models For The Pn Diode And The Npn And Pnp Transistor For Use In Computer Aided Design And Analysis Programs, Glenn Ronald Case

Doctoral Dissertations

"This work is concerned with the problem of developing suitable mathematical representations for the pn junction diode and npn and pnp transistors for use in computer aided design and analysis programs. The Ebers-Moll model as used in the Net-1 program has been considerably improved, particularly regarding base resistance prediction, prediction of high forward current behavior, and the addition of reverse breakdown terms. The resulting models show substantial improvement in representation of d-c and transient characteristics. Some improvement in a-c characteristics has also been obtained. Methods of obtaining parameters for the new model and several of the present models, given measured …

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Phase Equilibria And Thermodynamic Studies In The System Ca0-Fe0-Fe₂0₃₋Si0₂, Muharrem Timucin Jan 1969

Phase Equilibria And Thermodynamic Studies In The System Ca0-Fe0-Fe₂0₃₋Si0₂, Muharrem Timucin

Doctoral Dissertations

"A study of phase relations and thermodynamic properties of phases in the system CaO-FeO-Fe₂O₃-SiO₂ was conducted at 1450°C and 1550°C. The region of stability of the different phases was determined by microscopic examination of the specimens. The thermodynamic properties of liquid were determined by analyses of quenched samples equilibrated at oxygen pressures from about 10⁻¹¹ to 1 atm. Isothermal phase diagrams were constructed from data for 0, 5, 10, 20, and 30 weight percent silica sections of the CaO-FeO-Fe₂O₃-SiO₂ system, and the effect of temperature and increased silica additions on the oxygen solubility of the liquid oxides was measured. Multicomponent …

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Computer-Aided Design Of Lossless Non-Uniform Transmission Lines, Larry Lee Wesner Jan 1969

Computer-Aided Design Of Lossless Non-Uniform Transmission Lines, Larry Lee Wesner

Masters Theses

"A numerical iterative design technique is presented for the synthesis of lossless non-uniform transmission lines. A variational approach is used to minimize an error functional to which the system and boundary equality constraints have been adjoined by Lagrangian multipliers. The resultant network optimization conditions lead to an iterative scheme requiring analysis of the non-uniform line, analysis of an adjoint system and calculation of the error gradient in parameter space. A steepest descent procedure is used to optimize parameter values. Finite difference equations are used to provide an approximation model for implementation on the digital computer. A design example and a …

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The Anodic Dissolution Of Molybdenum In Acid Sulfate Solutions, Ching-Kuo Chen Jan 1969

The Anodic Dissolution Of Molybdenum In Acid Sulfate Solutions, Ching-Kuo Chen

Masters Theses

"The world's resources of metals are decreasing. Due to this and the cost of replacing corroded materials, it has come to be realized that prevention is better than cure. The increasing demand for molybdenum and molybdenum alloys has stimulated a great amount of research into the corrosion characteristics of these materials. The result of such research has assisted in the development of suitable molybdenum alloys and protective coatings to retard corrosion. When a molybdenum anode and a suitable cathode are immersed in an oxygen-free electrolyte and are connected to a direct current power source, molybdenum is dissolved. This process is …

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The Anodic Dissolution Of Molybdenum In Alkaline Solutions, Chen Hwei Chi Jan 1969

The Anodic Dissolution Of Molybdenum In Alkaline Solutions, Chen Hwei Chi

Masters Theses

"Details concerning the anodic dissolution of many metals in various solutions are still unknown. Discrepancies are found between the actual weight-loss of an electrode and that calculated from coulometric data. The purpose of this investigation was to study the anodic dissolution of molybdenum (Mo) in basic solutions to determine the apparent valence of Mo ions going into solution, the nature of any surface films formed during dissolution, and the polarization behavior. Three electrolytes were used: 1 N potassium hydroxide (pH = 13.6), 0.667 N potassium carbonate (pH = 11.5), and potassium carbonate-potassium sulfate mixture (pH = 9.5). chloride ion additions …

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The Use Of Turbulence Energy Equation In Boundary Layer Study, Ro-Chi Tai Jan 1969

The Use Of Turbulence Energy Equation In Boundary Layer Study, Ro-Chi Tai

Masters Theses

"A turbulent boundary layer problem has been studied analytically and compared with an available experiment in the literature. Correlations of the experimental data were made to investigate the validity of the commonly used empirical relations on turbulent shear stresses. It was found that the model which related the local turbulent shear stress linearly with the local turbulent kinetic energy, as used by Bradshow et. al., appeared to be most reasonable. combining this model with the expression of turbulent viscosity given by Boussinesq, it was then possible to introduce the turbulence-energy equation in addition to the governing equations of continuity and …

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Analog Simulation Of Mass Transfer In Droplets With Turbulent Internal Circulation, Jeffrey Tsai-Hwa Kuo Jan 1969

Analog Simulation Of Mass Transfer In Droplets With Turbulent Internal Circulation, Jeffrey Tsai-Hwa Kuo

Masters Theses

"The object of this thesis is to simulate the Handlos and Baron Model for mass transfer into droplets by using an iterative analog computer in order to obtain eigenvalue and other parameters in a series solution. The eigenvalues λn calculated in this work are compared with the results obtained by Wellek-Skelland using a variational technique and by Patel using numerical approaches on the digital computer. From the analytical series solution, one can calculate the fraction of solute extracted in the droplets as a function of droplet contact time. PACTOLUS, a digital-analog simulator, provides a check on the validity of …

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Experimental Determination Of Dynamic Properties Of Aluminum Including Poisson's Ratio, Terry Lee Holman Jan 1969

Experimental Determination Of Dynamic Properties Of Aluminum Including Poisson's Ratio, Terry Lee Holman

Masters Theses

"Two rods of 7075-T651 aluminum are longitudinally impacted to investigate the material's dynamic properties. The test rod, initially at rest, is instrumented with strain gages to record the strain-time history after the impact rod, accelerated to uniform velocity by an air gun launcher, strikes the test rod. A camera records the strain-time pattern displayed on an oscilloscope. The experiment indicates a consistent rise time of approximately 9 µsec. Simple one-dimensional theory correlates well with the experimental data. Compensation is included for the transverse sensitivity of the gages used. The dynamic values for both the modulus of elasticity and Poisson's ratio …

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A Study Of The Nucleate Boiling Of Liquid Nitrogen, Liquid Argon, And Liquid Carbon Monoxide From Atmospheric To Near The Critical Pressure, Craig Bauer Johler Jan 1969

A Study Of The Nucleate Boiling Of Liquid Nitrogen, Liquid Argon, And Liquid Carbon Monoxide From Atmospheric To Near The Critical Pressure, Craig Bauer Johler

Masters Theses

"The nucleate boiling curves of three corresponding states liquids (nitrogen, argon, and carbon monoxide) were analyzed. Each liquid was studied at pressures ranging from atmospheric pressure to near the critical pressure. Saturated liquid boiling was conducted from cylindrical heaters in the horizontal position having diameters of 0.75 inches and lengths of three inches. Liquid nitrogen was boiled from four different gold heat transfer surfaces; argon and carbon monoxide were boiled from the same gold surface. The critical heat flux correlation of Cobb and Park was further verified by agreement with the experimental critical heat flux ratios obtained in this investigation. …

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An Impact Sensitivity Study Of Reactive Materials, Carl E. Delong Jan 1969

An Impact Sensitivity Study Of Reactive Materials, Carl E. Delong

Masters Theses

"The impact sensitivity of a potassium chlorate, stabilized red phosphorous, Quso, and magnesium oxide mixture in a 34/14/4/2 ratio has been found to be about 18 ł 5 gram-centimeters for a 50% sensitivity to initiation. Chi-square tests at the 95% confidence level have determined that it is not possible to reject the hypothesis that the distribution is either normally distributed or log-normally distributed within the 50% range. Humidity, aging, and some additives were found to desensitize the mixture. Energy versus drop weight and test height curves show that momentum considerations are crucial over large test ranges in studies of impact …

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Current Characteristics Of Electrically Sprayed Glycerine, Larry Eugene Stoddard Jan 1969

Current Characteristics Of Electrically Sprayed Glycerine, Larry Eugene Stoddard

Masters Theses

"The current carried by electrically-sprayed glycerine was measured, and an empirical relation was obtained for single-jet spraying, given by I = KIV0.45M0.55̇d-0.18 where V is the electrode voltage, Ṁ the mass-flow rate, and d the electrode spacing, the electrodes being a capillary and collecting plate. Peculiarities of the current waveform, including an exponentially rising envelope, for unstable-jet spraying and multiple-jet spraying, were recorded"--Abstract, page ii.

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An Analysis Of A Standardized Digital Circuit Driving A Coaxial Cable, John Pitkin Lappington Jan 1969

An Analysis Of A Standardized Digital Circuit Driving A Coaxial Cable, John Pitkin Lappington

Masters Theses

"The expense of developing new circuit designs has forced electronic manufacturers to develop and use multipurpose circuits that can be adapted to fit many requirements. Sometimes this procedure leads to problems that would not have occurred if a circuit, designed to fit a particular application, had been developed. One problem of this type deals with the effect of improperly terminated coaxial cables loading output signals from a digital computer. The unterminated cable reflected the signal back in the computer. This did not affect the putout stage, but the preceeding [sic] driving stage was affected. The degradation of the output of …

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The Effect Of Structure On The Consolidation Of Compacted Unsaturated Clay Soils, William Joseph Graham Jan 1969

The Effect Of Structure On The Consolidation Of Compacted Unsaturated Clay Soils, William Joseph Graham

Masters Theses

"Contained in this paper are the results of research which was performed to investigate the relation between the volume-change mechanisms of shrinkage and one-dimensional compression for two clay soils, including some samples whose structures had been altered by the addition of flocculating and dispersing agents. Shrinkage tests were conducted with a special mold designed to facilitate the study of a soil's shrinkage path. consolidation tests on undisturbed samples and one-dimensional compression tests on unsaturated samples compacted in the vicinity of optimum moisture content were performed. A detailed study was made of a highly plastic red Missouri clay. Complications arose in …

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Some Aspects Of Aerated Open-Channel Flow At Shallow Depths And Low Velocities, D. L. Fread Jan 1969

Some Aspects Of Aerated Open-Channel Flow At Shallow Depths And Low Velocities, D. L. Fread

Masters Theses

"This study is concerned with the effect of entrained air bubbles on the open-channel hydraulics of water flowing at low velocities. The air bubbles are introduced into the flowing water by injecting diffused compressed air along the channel bottom. The variations of the velocity profile and velocity distribution energy coefficient of aerated and nonaerated flow are discussed. Empirical equations have been determined for the air concentration and increased depth of flow or "bulking" of the aerated open-channel flow. The investigation revealed a significant increase in the Manning roughness coefficient and the related Darcy friction factor for aerated flow relative to …

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A Flood Frequency Study For Small Watersheds In Missouri, Ronald Anthony Rusch Jan 1969

A Flood Frequency Study For Small Watersheds In Missouri, Ronald Anthony Rusch

Masters Theses

"The quantity and quality of streamflow data available on small watersheds in Missouri has improved in the last ten years. However, it will be years before there is sufficient data on both the large and small watersheds to enable investigators to conduct extensive studies in the state. This study of 70 small watersheds within the state of Missouri presents a technique to estimate the discharge from watershed of 25 square miles or less...Results from this study may be used in the design of small hydraulic structures such as culverts, bridges, and dams for small reservoirs"--Abstract, page ii.

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System Definition Of A Small, Economical General Purpose Computer, Thomas Elden Kreger Jan 1969

System Definition Of A Small, Economical General Purpose Computer, Thomas Elden Kreger

Masters Theses

"The major differences between commercially available electronic calculators and the small, general purpose computer are discussed. A computer system organization is proposed with low cost, physical compactness and user convenience as design objectives. In addition, a system block diagram and a set of micro-instructions are postulated. These micro-instructions are micro-programmed to provide floating point arithmetic capability and a library of function generating sub-routines"--Abstract, page ii.

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Scraped-Surface Heat Exchange, Kyung Jun Park Jan 1969

Scraped-Surface Heat Exchange, Kyung Jun Park

Masters Theses

"An experimental study was made to test a theory developed for scraped-surface heat exchange. The apparatus was a cylindrical vessel equipped with two blades and baffles, cooled in an ice bath. The experiments showed the approach of dimensionless temperature deviated greatly from the theoretical prediction. It was found that part of this effect was the result of a change in temperature of the scraped wall, which could be accounted for by using the overall heat transfer coefficient between the cooling medium and the apparatus. Measurements on water showed the cooling rate to be much faster than the theory would predict. …

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A Lyapunov Designed Model-Referenced Control System With Signum Function Adaptive Control Laws, James Steven Epstein Jan 1969

A Lyapunov Designed Model-Referenced Control System With Signum Function Adaptive Control Laws, James Steven Epstein

Masters Theses

"An examination of a model-referenced adaptive control system designed to satisfy the requirements of Lyapunov's direct method is made. It is found that each adaptive control loop requires a multiplier for its implementation. A new design is proposed which replaces the multipliers in the control loops by switches, thereby gaining a significant hardware advantage. A first order system designed by the new method is simulated on an analog computer and some refinements are made. The method is then generalized to include nth order systems. The poles of the model, however, are subject to some restrictions. Finally, the problems associated with …

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