Beyond Convention
As engineers approach the design of new and expanded convention centers around the country, they must consider not only the changing needs of convention-goers, but also the surrounding...
Developments in the Use of Infrasound for Protecting Fish at Water Intakes
Attempts to protect fish at water intakes with sound generating devices have been ongoing for decades. Past results have been equivocal. However, the recent availability of high energy,...
NDE for Steel Bridges
Nondestructive evaluation (NDE) is the only way to detect fatigue cracks hidden by the paint on steel bridges, and FHWA-sponsored research into the problem has been given highest priority....
Acoustic Emission Monitoring of Fatigue Crack Growth in HSLA-80 Steel Box Beams
An acoustic emission is a transient elastic wave generated by the rapid release of energy from a localized source within a material. There can be many sources of acoustic emission in a...
Measurement of Turbulent Properties in a Natural System
Instruments designed to measure flow properties in stratified estuaries, lakes and oceans are reviewed. Emphasis is given to the measurement of turbulent fluxes and recent developments...
Laboratory and Field Evaluation of Acoustic Velocity Meters
A project is currently underway to evaluate the performance of 27 acoustic flowmeters used at Hoover, Davis, and Parker Dams on the lower Colorado River. Field surveys and laboratory testing...
Recent Applications of Acoustic Doppler Current Profilers
A Broadband acoustic Doppler current profiler (BB-ADCP) is a new instrument being used by the U.S. Geological Survey (USGS) to measure stream discharge and velocities, and bathymetry....
Acoustic-Doppler Velocimeter (ADV) for Laboratory Use
A remote-sensing, three-dimensional (3D) velocity sensor has been developed and tested for use in physical model facilities. The sensor is based on the Acoustic Doppler principle and measures...
Field Performance of an Acoustic Scour-Depth Monitoring System
The Herbert C. Bonner Bridge over Oregon Inlet serves as the only land link between Bodie and Hatteras Islands, part of the Outer Banks of North Carolina. Periodic soundings over the past...
Design and Operation of a System to Monitor Sediment Deposition for Protection of an Endangered Mussel
The USGS, in cooperation with the COE, has designed and installed a system to continuously monitor changes in elevation of the river bed over the mussel bed located downstream of the Olmsted...
Design and Execution of Hydrodynamic Field Data Collection using Acoustic Doppler Current Profiling Equipment
Proposed major changes to the navigation channel depth in the Cape Fear River prompted an investigation of the existing hydrodynamics of the river system. The observed data are to be used...
NDE of Steel Bridges by Acoustic Emission
Acoustic emission technique (AE) was used to investigate fatigue cracking phenomenon during a series of laboratory tests of various bridge steels and during field testing of an in-service...
Signal Analysis for Quantitative AE Testing
Quantitative acoustic emission (AE) techniques can be used to monitor crack growth and to deduce microfracture mechanisms in quasi-brittle materials. Multichannel data acquisition systems...
Application of Acoustic Hydrosurvey Technology to the Mapping of Eelgrass (
Acoustic hydrosurvey technology provides an efficient and accurate means of surveying the distribution of submerged aquatic vegetation under some circumstances. The San Francisco District,...
Acoustic Doppler Current Profiler for Inlet Current Measurements
A BroadBand Acoustic Doppler Current Profiler (BroadBand ADCP) was used to survey tidal currents at Shinnecock and Moriches Inlets, Long Island, NY. Measurements were made remotely form...
Passive Acoustic Emission for Quantitative Evaluation of Freeze Thaw and Alkali Aggregate Reaction in Concretes
Several experiments are reported in which the progression of freeze thaw (FT), alkali-aggregate reaction (AAR), and internal cracking caused by mechanical loading were monitored using...
Damage Assessment in Concrete Using Acoustic Emission
An acoustic emission (AE) is a localized rapid release of strain energy in a stressed material. This energy release causes stress waves to propagate through the specimen. These acoustic...
Nondestructive Crack Identification by Acoustic Emission Analysis and Ultrasonic Frequency Response
Nondestructive evaluation (NDE) by the acoustic emission (AE) analysis and the ultrasonic testing (UT) on the spectral (frequency) response is studied to identify crack geometry. AE waveform...
Experimental Determination of the Relation Between the Damaged Zone and the Aggregate Size in Concrete Through Acoustic and Mechanical Techniques
The size of aggregates in concrete has an influence on the behavior of the material. The width of the localized band can be related to this characteristic. Different experimental techniques...
Laser Interferometric Characterization of Acoustic Emission Transducers
The characterization of the exact response of commercially available, piezoelectric and thin film, acoustic emission transducers is of fundamental importance for the nondestructive evaluation...
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