Engineering Commons^™

Reversed And Repeated Lost Tests Of Full-Scale Steel Frames, Lauren D. Carpenter, Le-Wu Lu

CCFSS Library (1939 - present)

No abstract provided.

Vibratory Roller Evaluation, Donald C. Newberry Jr.

Kentucky Transportation Center Research Report

In a field evaluation of vibratory rollers, an end-result specification based on a statistical analysis of densities obtained on previous construction projects indicated 98 percent of laboratory density (Marshall) to be desired for Bituminous Concrete, Class I Base. The minimum average of 5 density tests was set at 96.4 percent. Conventional rollers, vibratory rollers, and combinations thereof were qualified on the basis of density-growth curves determined on one or more 1000-foot test sections. An overall average compaction of 97.8 percent of Marshall density was obtained on the Cumberland Parkway project. Similar controls initiated on the Green River Parkway project were …

A Survey Of Reflective Sheeting For Highway Signs, Rolands L. Rizenbergs

Kentucky Transportation Center Research Report

A questionnaire (see the APPENDIX) was sent to highway agencies in all 50 states, the District of Columbia and Puerto Rico for the purpose of surveying state practices in regard to reflective sheeting purchase, usage specifications, testing, etc. The response was 100 percent and, thus, demonstrated a high degree of interest in the subject.

Responses to the questionnaire are tabulated on the attached tables. An attempt was made to report answers provided by the agencies without interpretation except in a few isolated cases where the necessafy information was available to properly relate the response to a given question. In a …

Stability Of A Side-Hill Embankment, Tommy C. Hopkins, Harry F. Girdler, Steve M. Yoder

Kentucky Transportation Center Research Report

The report submitted herein is a case history describing observations and in-depth analyses made at a highway site involving a massive, unstable side-hill embankment located on I-64 in Boyd County. The in-depth study was initiated in January 1973. The I-64 site was selected for study because it contained several design, construction and maintenance features as well as soil types that are typical of many highway embankments in Kentucky. Side-hill fill situations are common design problems and oftentimes have required extensive maintenance after construction. Major objectives of the study were to 1) determine the causes of instability of the I-64 embankment, …

Trajectories Describing The Evolution Of Polarized Light In Homogeneous Anisotropic Media And Liquid Crystals, Rasheed M.A. Azzam, N. M. Bashara, B. E. Merrill

Electrical Engineering Faculty Publications

Trajectories are given that describe the evolution of the ellipse of polarization in the complex plane for light propagating in a homogeneous anisotropic medium and along the helical axis of a cholesteric liquid crystal. For the general homogeneous anisotropic medium that exhibits combined birefringence and dichroism the trajectory is a spiral that converges to the low-absorption eigenpolarization. For pure birefringence the trajectory becomes a complete circle that encloses one eigenpolarization, whereas for pure dichroism the trajectory becomes an arc of a circle that ends at the low-absorption eigenstate. The case of a cholesteric (or twisted nematic) liquid crystal leads to …

The Alligators Will Get You, If You Don't Watch Out!, Tim Brady

Publications

This article relates which tools can help pilots prepare to land at unknown airports.

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.

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.

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.

Features Of A Separating Turbulent Boundary Layer As Revealed By Laser And Hot-Film Anemometry, R. L. Simpson, J. H. Strickland, P. W. Barr

Symposia on Turbulence in Liquids

Experiments have been performed to determine the fundamental nature of boundary layer separation produced by an adverse pressure gradient. Measurements upstream and downstream of the separation zone have been made utilizing laser and hot-film anemometry techniques.

A completely mobile backscattering laser anemometer was developed. This alone is a significant development because of the relatively long focal lengths required for measurements in a 36" wide wind tunnel. Signal processing was achieved by a digital signal sampling and storage system. Both mean and fluctuating velocities in both the unseparated and separated flow regions were measured. Experimental results are in fairly good agreement …