Content by David H. Parker

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Subtle Sources of Error in Laser Trackers Due to Dispersion in the Internal Optical Elements
David H. Parker
It is well known that the speed of light depends on the index of refraction of the medium in which the light is propagating. It is also well known that in a dispersive medium, the speed of an...
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Experimental Uncertainty Analysis for NDT on the CSX Wilbur Bridge
David H. Parker
A 154-page report by Moreu and LaFave in 2012 explains unique problems railroad bridge engineers must contend with. The gross weight of cars went from 200,000 pounds to 263,000 pounds in the...
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Using Electronic Distance Measurement Instruments in NDT and Structural Health-Monitoring Applications
David H. Parker
Electronic distance measurement (EDM) instruments, such as laser trackers, total stations, and handheld laser distance meters, have been used in a limited number of nondestructive testing (NDT) and...