We used a capacitive technique to determine the radial clearance between the piston and cylinder of a gas piston gauge. This method determines the effective area of a piston gauge pressure standard, independent of calibration against another piston gauge or manometer, as long as the diameter of the piston is dimensionally measured. It also allows an independent determination of piston gauge dis...

Pressure waves and vibrations in the heart and great vessels may be conducted to a manometer outside the body by a system of tubing filled with fluid. More than a metre of tubing is usually needed as the circulation is entered at an arm vein. Any such system has the following defects. 1. Delay in the transmission of the low frequency pressure waves to the manometer: the delay will vary slightly...

Methods The test is a combined one. One hand is put into ice-cold water and at the same time constriction is applied to the neck in order to increase the venous pressure in the head. The latter is done by means of an ordinary sphygmo-manometer with the blood pressure cuff round the neck. We have only used a pressure of 40 mm. Hg. in the cuff. Bloomfield (1947) and Bloomfield and Kelterman (1947...

This article reports the development of a solid state pressure transducer for use in the measurement of blood pressure. It is intended to act as a replacement gauge for the mercury and aneroid manometers used in conventional sphygmomanometers. It measures pressure in the range 0-300mmHg (0-40kPa) with a resolution of 1mmHg (0.13kPa) and an accuracy of +1mmHg (+0.13kPa) which is displayed on a l...

The miniature intracardiac manometer supplied a method for recording artefact-free pressure tracings from the heart and great vessels of man and the intact animal. This instrument has been applied to the procedure of cardiac catheterization. It has also been used to demonstrate that if motion artefacts can be minimized, the central pulse can be recorded with reasonable accuracy by means of mano...

OBJECTIVE Clinical observation has identified cases in which the negative pressures exerted on patient chest drains have appeared to far exceed the level of suction intended. This study was designed to test whether the use of high rates of airflow in typical pleural/mediastinal drainage systems exerts excessively high negative pressures on the chest drainage tube. METHODS Three pleural draina...

Vertical hydraulic gradient is commonly measured in rivers, lakes, and streams for studies of groundwater-surface water interaction. While a number of methods with subtle differences have been applied, these methods can generally be separated into two categories; measuring surface water elevation and pressure in the subsurface separately or making direct measurements of the head difference with...

The hydraulic conductivity of the membranes surrounding the giant axon of the squid, Dosidicus gigas, was measured. In some axons the axoplasm was partially removed by suction. Perfusion was then established by insertion of a second pipette. In other axons the axoplasm was left intact and only one pipette was inserted. In both groups hydrostatic pressure was applied by means of a water column i...