Although the ultrasonic pulsatility index (PI) is used as a test of arterial inflow, the relationship between proximal arterial stenosis and PI has not been fully evaluated. In a series of experiments on dogs, over 200 measurements of pressure, flow (using an indwelling electromagnetic flowmeter), and PI were made distal to implanted arterial stenoses of varying length (0.5--9 mm) and cross-sec...

The intraoperative measurement of the afferent circulation of the liver, namely the hepatic artery flow and portal venous flow was carried out upon 14 anesthetized patients having carcinoma in the splanchnic area, mainly in the head of the pancreas by means of transit time ultrasonic volume flowmeter. The hepatic artery flow, portal venous flow and total hepatic flow were 0.377 +/- 0.10; 0.614 ...

There are many problems in the traditional electromagnetic flowmeter. The problems involve three aspects. The first one is that the measurement precision is low. The second one is that the measurement range is narrow. The third one is that the test results are susceptible to interference. For the problems a new electromagnetic flowmeter controlled by single-chip microcomputer has been proposed....

The transit-time ultrasonic gas flowmeter plays a vital part in the measurement field with its unique advantages. In recent years, it has developed into research hotspot of flow measurement. However, while signal propagates gas, amplitude fluctuation is produced under condition energy attenuation and unstable field. This leads to inaccurate transit time that causes calculation errors. Aiming at...

This paper describes a combined field, laboratory, and numerical study of electromagnetic borehole flowmeter measurements acquired without the use of a packer or skirt to block bypass flow around the flowmeter. The most significant finding is that inflow through the wellbore screen changes the ratio of flow through the flowmeter to wellbore flow. Experiments reveal up to a factor of two differe...