A specially designed circular towing tan~ was developed at the Northeast Fisheries Center (NEFC) for calibrating plankton-net flowmeters . ashore in order to provide more accurate volume estimates and to save valuable shipboard time. Results of a cross-calibration experiment with a flume in use at the Massachusetts Institute of Technology (MIT) demonstrated that calibration factors produced by ...

Photoplethysmography (PPG) is a technique that permits noninvasive measurement of changes in the volume of tissues. A novel device uses PPG to assess changes in duodenal mucosal perfusion. When tested in septic piglets, data obtained using this device correlate with the blood lactate concentration and duodenal serosal microvascular blood flow as measured with a laser Doppler flowmeter. This new...

Cutaneous vasomotor reflexes (CVR), the transient waves of cutaneous vasoconstriction after stimuli, such as a cough, were recorded from the digits of patients with unilateral frontoparietal lesions using a laser doppler flowmeter. Vasoconstriction was 6-15 times greater on the fingers contralateral to the lesions, an effect which was independent of the temperature difference between limbs. CVR...

We wish to express our thanks to Prof. J. M. Peterson and Dr John Pryde of University College, Cardiff, for the loan of the Perspex respiration tank used in this work. We are also grateful to Prof. Sir Alexander Fleming, F.R.S., for animal accommodation, and to Prof. A. St G. Huggett for the loan of a flowmeter. The expenses ofthis work were in part defrayed by a grant from the Medical Research...

The blood flow teas measured continuously in the intact vortex vein of the anesthetized rabbit using an ultrasonic Doppler -flowmeter toith a frequency response of approximately 4 Hz. Blood flow correlated well ivith perfusion pressure (arterial pressure minus intraocular pressure). The intraocidar pressure was changed stepwise by perfusion from a saline reservoir, Tonometry teas performed tuit...

Blood flow was measured with the electromagnetic flowmeter in the saphenous artery bed (cutaneous) and in the distal femoral and popliteal beds (muscle). The effects of ischemia and of intraurterial injection with methacholine, 1-epinephrine and 1-norepinephrine were studied before and again after each injection of progressively increased doses of antiadrenergic drugs. These studies indicate a ...

The laser Doppler flowmeter has been shown to give a response from the cochlea during high intensity acoustic stimulation which is not related to blood flow through the cochlea. The magnitude of this response depends upon the intensity and frequency of stimulation and the location of the probe on the cochlea. Evidence is presented that the response is derived from the vibration of cochlear tiss...

An electromagnetic flowmeter system that has an accuracy of 0.1% and is insensitive to fluid conductivity was used to study the sensitivity to steady flow of a 6-mm cannular transducer. All measurements were carried out at 37°C. Sensitivity decreased with increasing hematocrit value whether flow was laminar or otherwise. With laminar flow and a given hematocrit value, the sensitivity also decre...

Cervical Carotid Imaging With a ContinuousWave Doppler Flowmeter • A noninvasive technique for carotid arteriography using an ultrasonic directional Doppler flowmeter to image the carotid bifurcations is described. The technique uses a position sensing arm to hold the sharply focusing probe and translates the position of arterial flow onto an image storage screen. By multiple manual sweeps acro...

This paper proposes a dynamic synchronous capture (DSC) algorithm to calculate the flow rate for an electromagnetic flowmeter. The characteristics of the DSC algorithm can accurately calculate the flow rate signal and efficiently convert an analog signal to upgrade the execution performance of a microcontroller unit (MCU). Furthermore, it can reduce interference from abnormal noise. It is extre...