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Articles 811 - 840 of 883

Full-Text Articles in Engineering

Closed-Loop Dynamic Response Of A Static Scherbius Drive., Aaron J. Miles, B. Lequesne Jan 1986

Closed-Loop Dynamic Response Of A Static Scherbius Drive., Aaron J. Miles, B. Lequesne

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Generalized root-loci techniques, for squirrel-cage motors have been extended to wound-rotor, slip-energy-recovery systems (static Scherbius drive). The influence of a feedback control loop on these root loci is considered. General conclusions on Scherbius drive dynamics, as well as supporting experimental results, are presented.

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Electronic Ballast Having Emitter Coupled Transistors And Bias Circuit Between Secondary Winding And The Emitters, Don Cronin Jan 1984

Electronic Ballast Having Emitter Coupled Transistors And Bias Circuit Between Secondary Winding And The Emitters, Don Cronin

Mechanical and Aerospace Engineering Faculty Research & Creative Works

An electronic ballast for energizing fluorescent lamps comprising a converter including a rectifier and a filter for converting an alternating source voltage into a direct current voltage, a network including first and second switching transistors, a tank circuit having a primary winding of a transformer, a secondary winding of the transformer for providing feedback of a portion of the voltage developed across the tank circuits and a bias circuit coupled between the opposite ends of the secondary winding and the emitters of the transistor for alternatively applying bias to the transistors, the network serving to convert a direct current voltage …

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Generalized Root-Loci Theory For The Static Scherbius Drive, B. Lequesne, Aaron J. Miles Jan 1984

Generalized Root-Loci Theory For The Static Scherbius Drive, B. Lequesne, Aaron J. Miles

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

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Generalized Root-Loci Theory For The Static Scherbius Drive, B. Lequesne, Aaron J. Miles Jan 1984

Generalized Root-Loci Theory For The Static Scherbius Drive, B. Lequesne, Aaron J. Miles

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Generalized root-loci techniques, developed in the mid 70's for squirrel cage motors, have been extended in the static Scherbius configuration to wound rotor, slip energy, recovery systems. This arrangement is now applied to large power drives in the 0.5 to 50 MW range. In this paper, general results applicable to all machines are presented for the open-loop control scheme, but only the sub synchronous mode of operation in which a voltage source type inverter is used is addressed. Copyright © 1984 by The Institute of Electrical and Electronics Engineers, Inc.

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Saint-Venant's Principle In Linear Elasticity With Microstructure, R. C. Batra Jul 1983

Saint-Venant's Principle In Linear Elasticity With Microstructure, R. C. Batra

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Toupin's version of the Saint-Venant principle in linear elasticity is generalized to the case of linear elasticity with microstructure. That is, it is shown that, for a straight prismatic bar made of an isotropic linear elastic material with microstructure and loaded by a self-equilibrated force system at one end only, the strain energy stored in the portion of the bar which is beyond a distance s from the loaded end decreases exponentially with the distance s. © 1983 Martinus Nijhoff Publishers.

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Linear Inversion Method To Obtain Aerosol Size Distributions From Measurements With A Differential Mobility Analyzer, Donald E. Hagen, Darryl J. Alofs Jan 1983

Linear Inversion Method To Obtain Aerosol Size Distributions From Measurements With A Differential Mobility Analyzer, Donald E. Hagen, Darryl J. Alofs

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The Use of a Differential Mobility Analyzer to Perform Aerosol Size Spectrum Measurements Requires an Inversion Method to Go from the Measured Sensor Responses to the Desired Size Spectrum Information. Here We Present a Linear Inversion Method that Can Be Run on a Microcomputer or a Small Minicomputer. It Does Not Use Some of the Approximations Made in the Techniques Currently Available and Hence Gives Better Inversion Accuracy. the Method Shows Good Immunity to Both Random and Systematic Experimental Error. It is Applied to Numerous Test Case Aerosols. © 1983 Elsevier Science Publishing Co., Inc.

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High Pressure Liquid Jet Nozzle System For Enhanced Mining And Drilling, B. P. Selberg Jan 1982

High Pressure Liquid Jet Nozzle System For Enhanced Mining And Drilling, B. P. Selberg

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This invention is directed to a nozzle configuration capable of enhancing the cutting and drilling effects of high pressure liquid fluid jets. The jet system is particularly adapted to configurations of two or more liquid jets which are oriented to converge at a common point. The internal nozzle configuration produces controlled instability in the jet stream causing a more rapid breakup into droplets which can be combined to produce very fast moving jets and slow moving jets when collision between droplets occur. The velocity of the fast jets so formed may be several times greater than the original velocity of …

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A Potential Problem With The Tsi Electrostatic Aerosol Classifier, Darryl J. Alofs, Max B. Trueblood Jan 1982

A Potential Problem With The Tsi Electrostatic Aerosol Classifier, Darryl J. Alofs, Max B. Trueblood

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

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Inversion To Obtain Aerosol Size Distributions From Measurements With A Differential Mobility Analyzer, Darryl J. Alofs, P. Balakumar Jan 1982

Inversion To Obtain Aerosol Size Distributions From Measurements With A Differential Mobility Analyzer, Darryl J. Alofs, P. Balakumar

Mechanical and Aerospace Engineering Faculty Research & Creative Works

To Measure Size Distributions of Sub micrometer Aerosols with an Electrical Differential Mobility Analyzer (DMA) Requires an Inversion Procedure. the Knutson (1976) and the Hoppel (1978) Inversion Procedures Were Numerically Investigated for the Case of Log-Normal Aerosol Size Distributions. It Was Found that the Hoppel Procedure Converges to the Same Result as that Given by the Knutson Procedure. the Computational Range for Geometric Mean Diameter (Χg) Was 0.025-0.25 Μm, and for Geometric Standard Deviation (Σg) Was 1.1-2.4. the Inversion Error Was Found to Be Greater Than 10% in Certain "Forbidden Zones" of Χg and Σ …

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Development Of A Friction Element For Metal Forming Analysis, W. D. Webster, Robert L. Davis Jan 1982

Development Of A Friction Element For Metal Forming Analysis, W. D. Webster, Robert L. Davis

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A three-dimensional finite element friction element has been developed. The friction element has been used in the analysis of round-to-square forward extrusion.Comparison with some limited experimental data is presented. © 1982 by ASME.

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A Mathematical Model Used In Conjunction With A Finite Element Analysis To Aid In The Design And Analysis Of Bourdon Tubes, R. C. Weber, Robert L. Davis Jan 1982

A Mathematical Model Used In Conjunction With A Finite Element Analysis To Aid In The Design And Analysis Of Bourdon Tubes, R. C. Weber, Robert L. Davis

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A mathematical model that describes a variety of Bourdon tube geometries has been used for the three-dimensional analysis of Bourdon tubes. The variation of the stresses and tip deflections with respect to the variables used in the mathematical model are then presented as an aid in the design and analysis of the Bourdon tube. The finite element program represents a user-orientated package for calculation of tip deflections and stresses. Stresses and deflections are compared to both strain gage data and instrumented tip deflections as well as published data to establish the credibility of both the model and computer program. © …

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Atmospheric Measurements Of Ccn In The Supersaturation Range 0.013-0.681%., Darryl J. Alofs, T. H. Liu Jan 1981

Atmospheric Measurements Of Ccn In The Supersaturation Range 0.013-0.681%., Darryl J. Alofs, T. H. Liu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Concentrations of Cloud Condensation Nuclei in the Atmosphere Were Measured at Rolla, Missouri, Near Ground Level. a Total of 432 Spectra Were Measured over a 10-Month Period. No Consistent Seasonal or Diurnal Pattern Was Observed. Possible Implications for Fogs and Stratus Clouds and for Nuclei Chemical Composition Are Discussed.-From Authorscloud Condensation Nuclei Rolla Missouri Fogs

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Novel Demonstration Of Total Internal Reflection, Dwight C. Look Jan 1981

Novel Demonstration Of Total Internal Reflection, Dwight C. Look

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

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Combined Heat And Lass Transfer In Mixed Confection Ower A Horizontal Flat Plate, T. S. Chen, F. A. Strobel Jan 1980

Combined Heat And Lass Transfer In Mixed Confection Ower A Horizontal Flat Plate, T. S. Chen, F. A. Strobel

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The combined effects of buoyancy forces from thermal and species diffusion on the heat and mass transfer characteristics are analyzed for laminar boundary layer flow over a horizontal flat plate. The analysis is restricted to processes with low concentration levels such that the interfacial velocities due to mass diffusion and the diffusion-thermo/thermo-diffusion effects can be neglected. Numerical results for friction factor, Nusselt number, and Sherwood number are presented for gases having a Prandtl number of 0.7, with Schmidt numbers ranging from 0.6 to 2.0. In general, it is found that, for the thermally assisting flow, the surface heat and mass …

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Rubber Covered Rolls-The Nonlinear Elastic Problem, R. C. Batra Jan 1980

Rubber Covered Rolls-The Nonlinear Elastic Problem, R. C. Batra

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The problem of the indentation of a rubberlike layer bonded to a rigid cylinder and indented by another rigid cylinder is analyzed. The rubberlike layer is assumed to be made of a homogeneous Mooncy-Rivlin material. The materially and geometrically nonlinear problem is solved by using the finite-element code developed by the author. Results computed and presented graphically include the pressure profile at the contact surface, stress distribution at the bond surface and the deformed shape of the indented surface. © 1980 by ASME.

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Nucleation Experiments With Monodisperse Nacl Aerosols., Darryl J. Alofs, M. B. Trueblood, D. R. White, V. L. Behr Jan 1979

Nucleation Experiments With Monodisperse Nacl Aerosols., Darryl J. Alofs, M. B. Trueblood, D. R. White, V. L. Behr

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Nucleation Experiments with Monodisperse NaCl Aerosols Showed Good Agreement with the Kohler Theory Relating the Critical Super-Saturation S//c to the Dry Size. Aerosols Produced by Condensing NaCl Showed the Same S//c as Those Produced by Evaporating Aqueous NaCl Solution Droplets. This Indicates that If There is an Energy Barrier in Going from a Dry NaCl Particle to a Solution Droplet, This Energy Barrier is Small. the Fact that the Evaporation Aerosol Particles Are Cubical Crystals and the Condensation Aerosols Are Amorphous Spheres is Shown to Make No Difference in the Nucleation Threshold. the Investigation Also Gives Insights into the Performance …

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Series Induction/Parallel Inverter Power Stage And Power Staging Method For Dc-Dc Power Converter, Don Cronin, John J. Biess Jan 1979

Series Induction/Parallel Inverter Power Stage And Power Staging Method For Dc-Dc Power Converter, Don Cronin, John J. Biess

Mechanical and Aerospace Engineering Faculty Research & Creative Works

An improved series inductor/parallel inverter power stage and power staging method for a transistor controlled DC-DC power converter in which the integrating capacitance is located in the output of the power stage transformer and the series inductor has a secondary winding connected across this capacitance for transferring stored energy from the inductor primary directly to the transformer output rather than through the transformer, and current flow through the transformer primary is controlled by two parallel, alternately conducting pulse-width-modulated transistors in a manner such that only a single transistor is located in the main current flow path at any given time. …

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Two-Dimensional Scattering From A Medium Of Finite Thickness, Dwight C. Look Jan 1979

Two-Dimensional Scattering From A Medium Of Finite Thickness, Dwight C. Look

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

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Split-Set Rock Bolt Analysis, Robert L. Davis Jan 1979

Split-Set Rock Bolt Analysis, Robert L. Davis

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A system of twelve equations have been developed for the elastic-plastic analysis of split-set roof bolts and these equations have been programmed for solution on the IBM 370/168 computer. Typical solutions have been presented in graphical form for comparison with experimental data. The results compare favorably for most of the split-sets providing the system parameters are properly specified. It appears that this analytical solution will be valuable to mining engineers since the solutions have been put in graphical form. Plots of the effects of the various parameters (material strength, material strain-hardening, friction, thickness, radius, angle of contact) on the holding …

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Performance Of A Dual-Range Cloud Nucleus Counter., Darryl J. Alofs Jan 1978

Performance Of A Dual-Range Cloud Nucleus Counter., Darryl J. Alofs

Mechanical and Aerospace Engineering Faculty Research & Creative Works

An Instrument for Measuring the Concentrations of Cloud Condensation Nuclei as a Function of Nucleus Critical Supersaturation (S//c) is Described. in the Range 0. 1% Less Than Equivalent to S//c Less Than Equivalent to 0. 1%, the Instrument is Operated as a Vertical Flow Thermal Diffusion Chamber. in the Range of 0. 016% Less Than Equivalent to S//c Less Than Equivalent to 0. 1%, the Chamber is Operated at 100% Humidity, and the Equilibrium Radii of the Nuclei Are Measured with an Optical Counter. This Paper Presents a Large Body of Data Taken in the Laboratory to Evaluate the Performance …

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Studies Of Vibrational Surface Modes In Ionic Crystals. I. Detailed Shell-Model Studies For The Unrelaxed (001) Face Of Seven Crystals Having The Rocksalt Structure, T. S. Chen, F. W. De Wette, G. P. Alldredge Jan 1977

Studies Of Vibrational Surface Modes In Ionic Crystals. I. Detailed Shell-Model Studies For The Unrelaxed (001) Face Of Seven Crystals Having The Rocksalt Structure, T. S. Chen, F. W. De Wette, G. P. Alldredge

Mechanical and Aerospace Engineering Faculty Research & Creative Works

We present a comprehensive, unified account of the lattice dynamics of unrelaxed (001) faces of seven crystals having the rock salt structure, three of which have an absolute gap between the acoustical and optical bulk bands (RbF, RbCl, and NaI) and four of which have overlap between these bulk bands (NaF, NaCl, LiF, and MgO). The results are obtained from calculations of the normal modes of a thin crystal film in which the ionic interactions are described by the rigid-shell model. An outline of the formulation of the shell model for the film is given, and the rapid convergence of …

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Multiple High Voltage Output Dc-To-Dc Power Converter, Don Cronin, Bertrand F. Farber, Hartmut K. Gehm, Daniel S. Goldin Jan 1977

Multiple High Voltage Output Dc-To-Dc Power Converter, Don Cronin, Bertrand F. Farber, Hartmut K. Gehm, Daniel S. Goldin

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Disclosed is a multiple output DC-to-DC converter. The DC input power is filtered and passed through a chopper preregulator. The chopper output is then passed through a current source inverter controlled by a squarewave generator. The resultant AC is passed through the primary winding of a transformer, with high voltages induced in a plurality of secondary windings. The high voltage secondary outputs are each solid-state rectified for passage to individual output loads. Multiple feedback loops control the operation of the chopper preregulator, one being responsive to the current through the primary winding and another responsive to the DC voltage level …

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Mixed Convection Across A Horizontal Cylinder With Uniform Surface Heat Flux, A. Mucoglu, T. S. Chen Jan 1977

Mixed Convection Across A Horizontal Cylinder With Uniform Surface Heat Flux, A. Mucoglu, T. S. Chen

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

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Optimal Cantilever Dynamic Vibration Absorbers, R. G. Jacquot, J. Earl Foster Jan 1977

Optimal Cantilever Dynamic Vibration Absorbers, R. G. Jacquot, J. Earl Foster

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This work considers the use of a double-ended cantilever beam as a distributed parameter dynamic vibration absorber applied to a single-degree-of-freedom system in the presence of sinusoidal forces. The problem is analyzed exactly and by an energy approach using a single mode approximation for the cantilever beam. The results for both techniques compare favorably and damping is introduced in the form of a complex beam modulus. Optimal tuning and optimal damping parameters are found for a given ratio of absorber mass to main mass. © 1977 by ASME.

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The Effects Of Main-Flow Radial Velocity On The Stability Of Developing Laminar Pipe Flow, F. C.T. Shen, T. S. Chen, L. M. Huang Jan 1976

The Effects Of Main-Flow Radial Velocity On The Stability Of Developing Laminar Pipe Flow, F. C.T. Shen, T. S. Chen, L. M. Huang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In studying the stability due to axisymmetric disturbances of the developing flow of an incompressible fluid in the entrance region of a circular tube, a generalized version of the Orr-Sommerfeld equation was derived which takes account of the radial velocity component in the main flow. The new terms in the generalized Orr-Sommerfeld equation are inversely proportional to the Reynolds number. The resulting eigenvalue problem consisting of the disturbance equation and the boundary conditions was solved by a direct numerical integration scheme along with an iteration procedure. Neutral stability curves and critical Reynolds numbers at various axial locations are presented. A …

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Installation Induced Stresses For Grouted Roof Bolts, R. N. Nitzsche, Charles J. Haas Jan 1976

Installation Induced Stresses For Grouted Roof Bolts, R. N. Nitzsche, Charles J. Haas

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The judicious use of roof bolts in stabilizing underground openings necessitates the ability to determine the state of stress in and around such bolts. A method of modeling a system of roof bolts is presented. This method is then applied in the determination of the state of stress due to bolt tightening. Two specific roof bolt configurations are considered: a fully grouted post-tensioned bolt and a post-tensioned bolt with grouted-end anchorage. The analysis showed that the grout annulus transferred nearly all of the bolt load 3nto the rock within a distance of 12 hole diameters from the point of bolt …

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Deformation Produced By A Simple Tensile Load In An Isotropic Elastic Body, R. C. Batra Jan 1976

Deformation Produced By A Simple Tensile Load In An Isotropic Elastic Body, R. C. Batra

Mechanical and Aerospace Engineering Faculty Research & Creative Works

It is shown that a simple tensile load produces a simple extension provided the empirical inequalities (Truesdell and Noll [1], eqn. 51.27) hold. © 1976 Noordhoff International Publishing.

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Numerical Simulation Of A Widely Used Cloud Nucleus Counter., Darryl J. Alofs, J. C. Carstens Jan 1976

Numerical Simulation Of A Widely Used Cloud Nucleus Counter., Darryl J. Alofs, J. C. Carstens

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The Performance of the Conventional Horizontal Plate Thermal Diffusion Chamber as a Cloud Nucleus Counter Was Studied. Numerical Calculations Were Performed in Order to Follow the Simultaneous Drop Growth and Sedimentation in the Spatially and Temporally Nonuniform Supersaturation Field. the Effect of Nuclei Distribution and Smallest Detectable Drop Size Were Investigated. the Results Indicate Order of Magnitude Uncertainty in the Count at 0. 1% Supersaturation, and a Factor of 2 Uncertainty at 1. 0% Supersaturation.

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A Closed-Form Solution For The Radiosity At The Edge Of A Rectangular Cavity, Alfred L. Crosbie Jan 1976

A Closed-Form Solution For The Radiosity At The Edge Of A Rectangular Cavity, Alfred L. Crosbie

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

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Mie Scattering Computations For Moderately Large Spherical Particles, Dwight C. Look Jan 1976

Mie Scattering Computations For Moderately Large Spherical Particles, Dwight C. Look

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

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