A hypodermic pressure manometer utilizing the bonded wire resistance strain gauge.
The recent development of the bonded resistance wire strain gauge has led to its use as a device for measuring physiological pressure phenomena. Further application of the strain gauge has been as an instrument for measuring intravascular blood pressures and other pressure phenomena in biology and medicine.
A simple model tensometric electromanometer for recording intravascular pressure
SummaryA strain gauge which we designed was adapted to record arterial and venous pressure.A natural vibration frequency of the moving parts of the transmitter in air was greater than 75 per sec. The damping factor of the liquid-filled system exceeded 1∶7.The following facts indicate the sensitivity of the instrument: when a type MOB-5 loop was employed the deflection of the light spot on the loop oscillograph tape was 2.5 mm per mm Hg (arterial pressure gauge) and 6.4 mm of water (venous pressure gauge).In addition provision was made for altering the sensitivity by changing the diaphragm in the gauge capsule.A readily procurable Soviet strain gauge amplifier type TU-4M or TU-6M, which incorporated a carrier frequency generator, was employed to amplify the signal received from the output of the strain-gauge bridge.The zero drift did not exceed 1–2 mm mercury during a period of 1 h.
Effect of superficial gas velocity on the particle temperature distribution in a fluidized bed with heat production
The heat transfer behavior of particles and gas in an olefin polymerization fluidized bed was numerically analyzed using an in-house developed 3-D computational fluid dynamics discrete element model (CFD-DEM). First the implementation of the model was verified by comparing simulation results with analytical results. A constant volumetric heat production rate was implemented in the particle energy equation to mimic the heat production due to the polymerization reaction. It was found that the probability density function (PDF) of the particle temperature becomes more homogeneous with increasing superficial gas velocity. Furthermore, instantaneous snapshots of the thermal driving force (the difference between the single particle temperature and bed-average gas temperature, Tp− ) for different heat production rates provide detailed insight in the particle temperature distribution inside the fluidized bed. The time- and bed-averaged particle convective heat transfer coefficient, which was calculated by Gunn׳s correlation, was found to be independent of the superficial gas velocity. This is explained by the fact that the relative velocity of gas and particles in the emulsion phase, where most of the particles and gas interact, is hardly influenced when increasing the gas superficial velocity. From the spatial distribution of Nusselt number, it becomes apparent that the high heat transfer regions are found in the wake of rising bubbles, whereas low heat transfer rates are found in the clouds of the bubbles.