scholarly journals Neutral Density Measurement of Ion Thruster with Differential Pressure Gauge

2014 ◽  
Vol 12 (ists29) ◽  
pp. Pb_73-Pb_78 ◽  
Author(s):  
Yoshinori NAKAYAMA ◽  
Kenichi NARISAWA
Keyword(s):  
Pressure Gauge ◽  
Density Measurement ◽  
Differential Pressure ◽  
Neutral Density ◽  
Ion Thruster

In-Situ Calibration of Differential Pressure Gauges on OBSIP Ocean Bottom Seismometers

2020 ◽  
Author(s):  
Gabi Laske ◽  
Adrian Doran
Keyword(s):  
Pressure Sensor ◽  
Broad Band ◽  
Pressure Gauge ◽  
Differential Pressure ◽  
P Wave ◽  
Earth Tides ◽  
Release Mechanism ◽  
Ocean Bottom ◽  
Ocean Bottom Seismometer

<p>A standard ocean bottom seismometer (OBS) package of the U.S. OBS Instrument Pool (OBSIP) carries a seismometer and a pressure sensor. For broadband applications, the seismometer typically is a wide-band or broad-band three-components seismometer, and the pressure sensor is a differential pressure gauge (DPG). The purpose of the pressure sensor is manifold and includes the capture of pressure signals not picked up by a ground motion sensor (e.g. the passage of tsunami), but also for purposes of correcting the seismograms for unwanted signals generated in the water column (e.g. p-wave reverberations).<br>Unfortunately, the instrument response of the widely used Cox-Webb DPG remains somewhat poorly known, and can vary by individual sensor, and even by deployment of the same sensor.</p><p>Efforts have been under way to construct and test DPG responses in the laboratory. But the sensitivity and long‐period response are difficult to calibrate as they  vary with temperature and pressure, and perhaps by hardware of the same mechanical specifications.  Here, we present a way to test the response for each individual sensor and deployment in situ in the ocean. This test requires a relatively minimal and inexpensive modification to the OBS instrument frame and a release mechanism that allows a drop of the DPG by 3 inches after the OBS package settled and the DPG equilibrated on the seafloor. The seismic signal generated by this drop is then analyzed in the laboratory upon retrieval of the data. </p><p>The results compare favorably with calibrations estimated independently through post‐deployment data analyses of other signals such as Earth tides and the signals from large teleseismic earthquakes. Our study demonstrates that observed response functions can deviate from the nominal response by a factor of two or greater with regards to both the sensitivity and the time constant. Given the fact that sensor calibrations of DPGs in the lab require very specific and stable environments and are time consuming, the use of in-situ DPG calibration frames pose a reliable and inexpensive alternative. </p>

HYDROSTATIC LEVEL FOR ELEVATION SURVEYING

Geophysics ◽  
1951 ◽  
Vol 16 (3) ◽  
pp. 486-493 ◽  
Author(s):  
Kenneth C. Crumrine ◽  
John E. Palmer
Keyword(s):  
Field Test ◽  
Pressure Gauge ◽  
Water Reservoir ◽  
Maximum Error ◽  
Temperature Correction ◽  
Probable Error ◽  
Differential Pressure ◽  
Closed Loops ◽  
Hydrostatic Level

A hydrostatic level for elevation surveying has been developed which indicates differences in elevation by measuring the head of a column of water. It is essentially a differential pressure gauge connected by a length of water‐filled plastic tubing to a water reservoir. The instrument is described and the results of a field test on 73 miles of traverse are given. A probable error of about 6 cm and a maximum error of 33 cm were found for closed loops of 3 to 5 miles after proration of closure errors. On unsupported traverses of 3 to 5 miles, application of a temperature correction appeared desirable and resulted in a probable error of about 10 cm and a maximum error of 52 cm. The range of the instrument is from minus to plus 10 meters and the least count is 2 cm. It is read to the nearest centimeter.

scholarly journals Calibration of deep sea differential pressure gauge

2009 ◽  
Vol 2009 ◽  
pp. 141-148 ◽  
Author(s):  
Eiichiro Araki ◽  
Hiroko Sugioka
Keyword(s):  
Deep Sea ◽  
Pressure Gauge ◽  
Differential Pressure

Design on Flow Measurement Solution with Intelligent Efflux Coefficient Standard Throttling Gear

2013 ◽  
Vol 325-326 ◽  
pp. 783-786
Author(s):  
Quan Sheng Duan ◽  
Qing Zhao ◽  
Li Cui Wang
Keyword(s):  
Lower Limit ◽  
Flow Measurement ◽  
Measurement Accuracy ◽  
Intelligent System ◽  
Design Method ◽  
Pressure Gauge ◽  
Measurement Range ◽  
Differential Pressure ◽  
National Standards

t is an in-depth research on the span measurement range ratio that standard throttling gear measures the flow is too small, and proposes the design method of multi-efflux coefficient standard throttling gear. Expanding the lower limit of measurable flow according to the relevant national standards GB/T2624-2006. Solution divides the span measurement range into several segments, each piece span measurement range corresponds to a differential pressure gauge, and calculates corresponding efflux coefficient depending on the GB/T2624-2006 to get many outflow coefficients on the different span measurement sub-range section. Intelligent system chooses corresponding efflux coefficients based on different differential pressure, and ensures measurement accuracy at the same time of expanding the lower limit.

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