Columbia Gas System Service Corporation

Southern California Gas Company

New York Gas Group

Johns Hopkins University

Ralph F Cohn

John C Murphy

Patrick J Moran

Glenn S Hartong

James W Wagner

Electrical current distribution in the soil surrounding a buried pipeline is detected by applying an AC electrical potential between the pipe and a buried electrode spaced from the pipe. The magnetic field at spaced localities along the pipe arising from currents transverse to the pipe is detected. Additionally, a potential containing a plurality of alternating frequencies is similarly applied to the pipe and the magnetic field induced by the resulting electrical current both along the pipe and transversely of the pipe is detected. The magnetic field is detected by correlation discrimination at spaced locations along the pipe and across the spectrum of the impressed frequencies. The detected data is used to determine the capacitance and resistance of the soil/pipe interface at localities along the pipe and to generate impedance plots which indicate characteristics of that interface.

Non-invasive, high resolution detection of electrical currents and

Dynamic imaging microellipsometry (DIM) is a rapid full-field imaging technique for high resolution studies of thin-films. The DIM concept is based on radiometric polarizer, compensator, specimen, analyzer (PCSA) ellipsometry combined with video and image processing techniques. The theoretical basis for this approach is developed using the Jones vector and matrix formalism. Basic systems design is presented with error model predictions of ellipsometric accuracies better than 0.1.degree. for full-field .psi. and .DELTA. images captured in a few seconds with spatial resolution under 10 microns.

Dynamic imaging microellipsometry

Growing community of inventors

Worcester, MA, United States of America

Ralph F Cohn