Digital Commons Network^™

The Design And Analysis Of An Electro-Pneumatic Signal Converter, Richard K. Thornton

Theses and Dissertations

In the field of process control it is desirable to study dynamic characteristics such as frequency response and distortion when determining just how equipment is to be controlled. Pneumatic controllers, transmitters, control valves, etc., all have dynamic behaviors which can be expressed mathematically as transfer functions. Each component plays an important role in determining the entire system behavior. Frequency response is one technique used in developing a component’s transfer function. By driving a device with a sinusoidal signal of fixed amplitude and frequency the output amplitude and phase shift are measured and compared with that of the input. Varying the …

Finite Conductance Element Method Of Conduction Heat Transfer, E. Clark Lemmon

Theses and Dissertations

One of the basic goals in engineering is to formulate models which will provide a means for analytically predicting observed phenomenon. For some time, the partial differential equations describing the steady state and transient conduction of heat within a solid have been available. However, the straight forward use of these equations is often restricted due to the surface geometry of the solid. If the surface geometry is at all irregular, exact solutions will in general not exist. In that case, a solution is sought by some approximate numerical technique. The two techniques most often used are the finite difference method …

An Aerodynamic Investigation Of The Causes Of Overhead Electrical Transmission Line Gallop, Eric Nathan Skousen

Theses and Dissertations

Overhead electrical transmission lines vibrate due to the action of a prevailing wind. These cable vibrations can be classified into two categories— high-frequency and low-frequency. The high-frequency vibrations, "aeolian" vibrations or "singing wires," is a low-amplitude phenomenon. It has been largely controlled with the use of various mechanical dampers [l, 2],

Numerical Study Of The Turbulent Boundary Layer In A Hypersonic Nozzle, Joan Patricia Gosink

Mechanical & Aerospace Engineering Theses & Dissertations

A numerical study of the turbulent boundary layer in a hypersonic nozzle is presented. The boundary layer equations are solved by a second order, implicit finite difference scheme developed at Langley Research Center. The technique is applicable to laminar, transitional or turbulent compressible or incompressible boundary layer flows for planar or axisymmetric geometries. A technique is presented for utilizing experimental data to start the finite difference solution.

Turbulent boundary-layer measurements on axisymmetric nozzle walls at Mach number 6 are presented and compared with numerical predictions obtained by starting the solution in the stagnation chamber and from a downstream experimental station. …

Plastic Subassemblage Anlysis And Tests For Rigid High-Rise Steel Frames, J. Hartley Daniels, S. W. Kim

CCFSS Library (1939 - present)

No abstract provided.

Fatigue Analysis Of Central Bridge Deduced From Strain Gage Data And Probability Analysis, R. J. Bruner Iii

Kentucky Transportation Center Research Report

This report presents evaluations of the load history of the Central Bridge from both strain gage data and probability analysis. Estimation of remaining service life is made through fatigue criteria. Also included is a comparison (from strain gage data) of live load stresses carried by parallel eye bars. An appendix provides a user's manual for the computer program for probability-based analyses of load events and fatigue-life computations.

Establishment And Maintenance Of Roadside Plantings And Turf, Kenneth N. Franks

Kentucky Transportation Center Research Report

A series of experimental investigations initiated by the Kentucky Highway Department over a six-year period were designed for the purpose of studying the I adaptability, establishment, and maintenance of roadside plantings and turf, including the stabilization and management of roadside soils.

Experimental Installations Of Impact-Attenuating Devices, Jerry G. Pigman, William M. Seymour, Don L. Cornette

Kentucky Transportation Center Research Report

From a survey of the interstate system in Kentucky, 26 gore sites were found to be eligible for safety improvements. Energy absorbing barriers have been installed at five. Barriers are planned at 11 sites; seven sites have been contour graded; and three sites have been dismissed from consideration.

HI-DRO Cushions and Fitch Inertial Barriers were found to be effective crash cushions. HI-DRO Cushion maintenance costs per impact were less than those for Fitch Inertial Barriers; however, initial costs of materials and installation were higher. The HI-DRO Cushion is generally more adaptable to narrow and relatively short areas than either the …

Wheels Are Square, Tim Brady

Publications

This article discusses the possibilities to extend battlefield support using aircraft equipped with air cushion landing systems (ACLS). The ACLS are less costly than traditional landing systems but provide some new flying skills, like how to move the aircraft after the air cushion has been deflated.

Simulation Of A Single Feed Fractional Distillation Column Using The Thiele-Geddes Procedure, M. S. Abolahrari

Theses

This thesis constitutes a simulation model of a single feed frational distillation column consisting of a single phase distillate, liquid or vapor product, an equilibrium stage reboiler, and a cascade consisting of theoretical equilibrium stages. The model limitations in addition to the single feed and the single phase distillate are 20 identifiable components, and 100 theoretical equilibrium stages. The thermodynamic data required are vapor-liquid equilibrium data and vapor-liquid enthalpy data, both assumed to be correlatable as functions of temperature. Compositional dependence of the thermodynamic data is ignored, but minor pressure variations throughout the cascade can be incorporated into the vapor-liquid …

The Chemistry Of Azides, Edward D. Nelson

Theses

A review of the decomposition of alkyl and aryl azides by thermolysis and photolysis has been accomplished. Organic azides are a very distinct species that undergo its own unique reactions. Azides decompose to form an electron deficient nitrogen having a sextet of elcctrons. This is called a Nitrene. Nitrenes can exist in the singlet or triplet state. The triplet behaves like a diradical. General and specific reactions of nitrenes have been shown with detailed mechanisms accounting for the products. The main modes of nitrene stabilization are rearrangement, hydrogen abstraction and insertion. Insertion is characteristic of singlet species and abstraction characteristic …

Emisari: A Management Information System Designed To Aid And Involve People, Rod L. Renner, Robert M. Bechtold, Charles W. Clark, David O. Marbray, Ronald L. Wynn, Nancy H. Goldstein, United States. General Services Administration. Office Of Preparedness. Mathematics And Computation Laboratory.

Computerized Conferencing and Communications Center Reports

The EMISARI System described in this paper represents a major departure from conventional MIS design. It is oriented not toward data per se, but rather toward activities of the people who generate and use the data. Thus it provides not merely for reporting up the chain of command, but also for dissemination of policy guidance and reference material down the chain, and for lateral communication among all users. It places a premium upon flexibility, to permit rapid system modifications in response to changes in user functions and needs and it offers a greatly simplified operation, to avoid any necessity for …

Slope Stability Analysis: A Computerized Solution Of Bishop’S Simplified Method Of Slices, Steve M. Yoder, Tommy C. Hopkins

Kentucky Transportation Center Research Report

A computer program based on Bishop's simplified method of slices (1954) and capable of analyzing the slope stability of a multilayered soil mass is described. The computer program was specifically developed for analyzing the slope stability of highway bridge approach embankments; however, it can be applied to a broad spectrum of practical slope configurations and bearing capacity problems. Details of the use, applications, and accuracy of the program are presented. Important features of the computer program include a grid type, search operation for locating the critical shear surface and a ledger printout of the forces acting on each individual slice. …

Evaluation Of The High-Accident Location Spot-Improvement Program In Kentucky, Kenneth R. Agent

Kentucky Transportation Center Research Report

The purpose of this study was to determine the overall effectiveness of the spot-improvement program in Kentucky. Safety improvements have been made at 349 locations (through June 30, 1971) since the program started in 1968. Before-and-after accident summaries were made at these locations as well as locations where the investigation resulted in no recommendations for improvements. It was found that the second-year before accident data was more representative of long-term accident experience than the first-year before data. From the analyses, it was found that the spot-improvement program has resulted in a significant reduction in accidents at high-accident location sites. The …

Settlement Of Highway Bridge Approaches And Embankment Foundations, Bluegrass Parkway Bridges Over Chaplin River, Tommy C. Hopkins

Kentucky Transportation Center Research Report

The report examines the cause of a differential settlement between the highway approach embankments and bridge decks and abutment tilting at a bridge site located on the Bluegrass Parkway in Kentucky. The site contains several design, construction and maintenance features and soil types that are typical of many bridge sites in Kentucky. The approach embankments are side-hill fills. The approach pavements have settled several inches and have been patched on numerous occasions. Each of the four abutments give the appearance of having tilted backward toward the backfill. However, closer examination shows that the abutments have moved laterally toward the bridge …

Gear-Up Landings, Or...Let It All Hang Out, Tim Brady

Publications

Gear-up landings, or belly landings, continue to plague civilian, military and commercial aviation. A study has begun on a new effective device to warn pilots if the landing gear is not deployed correctly before landing.

Heat Transfer In Intrinsic Thermocouples;Application To Transient Temperature Measurement Errors., Ned R. Keltner

Mechanical Engineering ETDs

The use of intrinsic thermocouples to measure rapid temperature variations of electrically conductive materials has become increasingly popular because of their unique characteristics: rapid response, versatility, reliability, relative simplicity and low cost. However, in some of the applications, the variations are so rapid that the heat transfer process between the substrate and the thermocouple wire induces large errors in the temperature measurements. In these situations, proper interpretation of the experimental data required an accurate description of the response characteristics of the thermocouple.

Turbulence Measurements In Submerged Water Jets By Electromagnetic Induction Anemometry, Walter C. Mih

Symposia on Turbulence in Liquids

This paper describes the measurement and data analysis of the turbulence in a two-dimensional water jet discharging from a thin slot into a large body of stationary water having the same width as the slot. Tap water without additives was used as the flow medium. The electromagnetic induction method (commonly known as magnetohydrodynamics, or the MHD method) was used to sense the fluctuation velocities in the diffusion zone of the jet. A DC magnet was placed outside the flow field with the magnetic flux density of 885 Gauss perpendicular to the plane of homogeneity of the two-dimensional flow field. A …

Hydrogen-Bubble Flow-Visualization: Limitations In Drag Reducing Polymer Solutions, George L. Donohue

Symposia on Turbulence in Liquids

Hydrogen-bubble flow-visualization experiments have demonstrated that distinct bubble pulses cannot be obtained in water solutions of polyacrylamide of high enough molecular weight to cause drag reduction at low shear stresses. Good bubble pulses were obtained in poly(ethylene oxide) and in surfactant solutions, but they did not cause drag reduction at feasible shear stresses.

Front Matter, University Of Missouri--Rolla

Symposia on Turbulence in Liquids

No abstract provided.

Measurement Of Unsteady Flows In Mercury With Hot-Film Anemometers, Charles A. Sleicher, G. B. Lim

Symposia on Turbulence in Liquids

The difficulties in making turbulence measurements in liquid metals are discussed briefly. Attention is then focused on the problem of frequency response attenuation of hot-film anemometers by the thermal capacity of the thermal boundary layer near cylindrical sensors. A solution is given to the problem of heat transfer from an infinite cylinder normal to the potential flow of a fluid with a small sinusoidal velocity component. Application of the results to anemometer measurements is discussed. Some preliminary experiments on dynamic calibration are reported, and they are in reasonable agreement with the theory for Peclet numbers less than one.

Statistical Analysis Of Instantaneous Velocities In Turbulent Flow Of Dilute Viscoelastic Solutions, A. L. Rollin, F. A. Seyer

Symposia on Turbulence in Liquids

An experimental study, based on streak photograph determination of instantaneous velocities, was directed at determining the structure of turbulence within the boundary layer and core regions of circular pipes. The measurements lend support to the ejection phenomenon as the mechanism controlling drag reduction.

A correlation factor, defined as the ratio of the observed number of positive instantaneous radial velocities, to the observed number of negative instantaneous radial velocities, suggests acceleration in the radial direction as the elements of fluid move through the sublayer. The correlation factor also provides information about the thickening of the boundary layer for drag reducers relative …

Oceanic Shear Measurements Using The Airfoil Probe, Thomas Osborn, Thomas Siddon

Symposia on Turbulence in Liquids

Vertical profiles of salinity and temperature in the ocean reveal fluctuations with length scales as small as a few mil 1imeters. These fluctuations, called microstructure by oceanographers, are the small scale results of turbulent mixing processes. It is hoped that through the study of microstructure we can evaluate the relative importance of different sources of the turbulent energy (e.g., tides, large scale internal waves, etc.) and the mechanisms for generation of the turbulence (e.g., wave overturn, shear instability, etc.).

There is a considerable body of evidence to suggest that shear instability is an important mechanism in the generation of ocean …

Flow Visualization Studies On Drag-Reducing Turbulent Flows, R. H. J. Sellin

Symposia on Turbulence in Liquids

Flow visualisation studies in a square duct of internal dimensions 44.5 x 44.5 mm are reported. The flow marker is a stream of opaque white dye, released from a downstream facing stationary tube, and it is photographed through the plexiglass wall of the duct. The point of dye release can be traversed in a direction perpendicular to the duct wall and three locations are investigated, two in the core of the flow and one in the near- wall region. By using Is exposure times photographs are obtained of a dye dispersion cone and the cone angle is measured and related …

Measurement Of Reynolds Stress And Turbulence In Dilute Polymer Solution By Laser Velocimeter, Samuel E. Logan

Symposia on Turbulence in Liquids

Measurements of Reynolds stress and axial and transverse turbulence intensities have been made in turbulent pipe flow of a dilute solution of high molecular weight polymer and compared to measurements made with pure water. A laser velocimeter capable of measuring these turbulence parameters has been developed and utilized.

Axial turbulence intensities are consistent in behavior and magnitude with previous polymer results and the measurements of transverse intensity and Reynolds stress are similarly well behaved and self consistent. Sublayer thickening in drag reducing polymer solution is observed, in consonance with earlier work. New results include demonstration that the turbulent shearing stress …

Ldv Measurements In Turbulent Free Convection, R. J. Adrian

Symposia on Turbulence in Liquids

The design and performance of a laser Doppler velocimeter (LDV) used in a turbulent water-overice convection experiment are described. The LDV was operated in a reference beam mode with an ultrasonic diffraction grating shifting the reference beam frequency to provide bipolar sensing of the vertical velocity, and a phase-locked loop was used to demodulate the Doppler frequency information. The maximum observed velocities in the experiment were ± 1 mm/sec, and the accuracy of instantaneous measurement was limited by Brownian motion and laser line width to ± .04 mm/sec for a 2 Hz frequency response. The practical difficulties encountered in this …

Measurements In Turbulent Water And Two-Phase Flows By Laser Anemometry, A. Melling, J. H. Whitelaw

Symposia on Turbulence in Liquids

Measurements of the mean and rms values of the longitudinal velocity in a rectangular duct are reported. These results were obtained in a water flow using a laser anemometer. The important design criteria which facilitated the measurements are described and gradient, transit-time, noise and refractive-index corrections are specifically discussed. The results demonstrate the development of a rectangular duct flow and, in particular, reveal that a small lack of symmetry at the duct entrance can readily be identified in the normal- stress results, 37 hydraulic diameters downstream.

The possibility of utilizing water droplets in steam and gas bubbles in water to …

Individual Realization Laser-Doppler Technique Applied To Turbulent Channel Flow, W. G. Tiederman, D. K. Mclaughlin, M. M. Reischman

Symposia on Turbulence in Liquids

Measurements of the mean and turbulence intensity of the streamwise velocity component in a fully developed, two-dimensional channel flow of water are presented. The measurements were made with the individual realization laser Doppler technique and emphasize the near-wall region of the flow. A dual-scatter optical arrangement was used which employs 90° scattering and yields a probe volume whose length normal to the wall is 0.0075 inches. A correction has been made to the data that accounts for the statistical biasing which occurs in the individual realization technique. The corrected data demonstrate that the individual realization technique can yield accurate velocity …

Analysis Of A Laser Correlation Anemometer, L. Lading

Symposia on Turbulence in Liquids

An analysis of a laser anemometer is given. The anemometer is based on the cross correlation of the random signals generated by the scattering from -- and/or extinction of -- two parallel laser beams. The basic set-up is compared with the laser Doppler anemometer.

It is shown that the correlation function exhibits a broadening and generally also a skewness - equivalent to the broadening (transit time) and skewness (velocity gradients) of the Doppler spectrum.

The conditions for "instantaneous point" measurements are derived.

It is shown how a particle (drop/bubble) size versus particle velocity spectrum can be obtained by appropriate electronic …

Optimization Of An Lda System, Robert Smid

Symposia on Turbulence in Liquids

This paper discusses the various considerations leading to the optimization of a laser Doppler anemometer for measurements in the flows of gases, liquids, and solids. The requirements placed on the various parameters of the optics by the experiment are discussed in general for different modes of operation. Expressions determining these optical parameters in certain instances given by various authorities are presented and compared. This includes such topics as: laser power, particle size, measuring volume size, optical variation in transmitting and receiving optics, and photodetector selection.