Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 3 of 3
Full-Text Articles in Engineering
A Transient Electromagnetic Flowmeter, Paul J. Lefebvre, William W. Durgin
A Transient Electromagnetic Flowmeter, Paul J. Lefebvre, William W. Durgin
Office of the Provost Scholarship
An electromagnetic flowmeter was developed to measure transient flows with a frequency response of 60 Hz. The approach taken was to develop suitable electronics to replace the electronics of a commercially available electromagnetic flowmeter normally used for steady-state operation. Use of the commercially available flowmeter body, which includes the magnetic coils, core, and signal electrodes, provided a relatively economical means of fabricating the transient flowmeter. A transient flow calibration facility consisting of a free-falling water column was also designed and built. Results of the calibrations are presented and show that the flowmeter can accurately measure transient flows up to the …
Shear Layer Coupling With Side-Branch Resonators, D. D. Erickson, William W. Durgin, C. F. Maguire Iii, M. J. Moeller
Shear Layer Coupling With Side-Branch Resonators, D. D. Erickson, William W. Durgin, C. F. Maguire Iii, M. J. Moeller
Office of the Provost Scholarship
High velocity flow past the junction of a side branch with a pipe can result in the excitation of depth-mode standing waves in the branch. The shear layer separating the main stream flow and the cavity provides coupling between the driving and the driven flow. Photographic evidence indicates that large scale vortex structures develop at the shear layer. The vortex formation process involves strongly non-linear instability of the shear layer and may be characterized as a non-linear fluid mechanical oscillator. The standing wave system formed in the cavity is essentially an acoustic wave system of nearly linear character. The principle …
Interpretation Of Venous Occlusion Plethysmography Using A Nonlinear Model, F. A. Anderson, Jr., William W. Durgin, H. Brownell Wheeler
Interpretation Of Venous Occlusion Plethysmography Using A Nonlinear Model, F. A. Anderson, Jr., William W. Durgin, H. Brownell Wheeler
Office of the Provost Scholarship
Venous occlusion plethysmography (VOP) is a noninvasive technique widely employed for the detection of deep-vein thrombosis. Previous reports that VOP outflow curves are closely fit by a first-order exponential suggest that venous compliance and resistance are nearly constant. Typically, however, the venous compliance function has a sigmoid shape; in addition, the resistance in a collapsing tube must increase. This paradox was resolved by the surprising finding that for realistic nonlinear compliance and resistance these nonlinearities cancel, producing a quasilinear venous outflow that approximates a simple exponential.