Magnetometer Respirometer for Laboratory and Diving Studies

Abstract

To construct and test a system for the measurement of respiratory tidal volume and respiratory rate that avoids the limitations and disadvantages of the usual mouthpiece, face masks, and neck seals in a plethysmograph. FINDINGS A respirometer based on the use of two pairs of magnetic coils placed on the chest and abdomen, as described by Mead and co-workers, will reproducibly measure tidal volume as well as respiratory rate. APPLICATIONS This system, at its present stage of development, can be used in the laboratory for measurement of tidal volume and respiratory rate when the use of mouthpieces, face masks, and neck seals is undesirable. By the use of a miniature tape recorder and a pressureproof underwater housing, it should be satisfactory for measurement of respiratory rate and tidal volume on SCUBA, Hoka, and hard-hat divers. ADMINISTRATIVE INFORMATION This investigation was conducted as part of In-House Work Unit Number MR011.01-5000-Physiological Limits in Saturation-Excursion Diving. The present report is No. 1 on that Work Unit.

Gas bubbles electrolytically generated at microcavity electrodes used for the measurement of the dynamic surface tension in liquids

“…Concerning the behavior of gas bubbles generated by sparging, it was observed in the literature [5] that the frequency of these bubbles generated at a constant gas flow increases when the surfactant concentration increases (the dynamic surface tension decreases). On the other hand, it was observed that, if the surfactant concentration is maintained constant (constant dynamic surface tension), the bubble frequency increases when the gas flow is increased [6].…”

Gas Bubbles Electrolytically Generated At Microcavity Electrodes (MCE) Used For The Measurement Of The Dynamic Surface Tension In Liquids

“…Concerning the behaviour of gas bubbles generated by sparging, it was observed in literature [5] that the frequency of these bubbles generated at a constant gas flow increases when the surfactant concentration increases (the dynamic surface tension decreases). On the other hand, it was observed that, if the surfactant concentration is maintained constant (constant dynamic surface tension), the bubble frequency increases when the gas flow is increased [6].…”