scholarly journals WAVE MEASUREMENT WITH DIFFERENTIAL PRESSURE GAUGES

1984 ◽  
Vol 1 (19) ◽  
pp. 51 ◽  
Author(s):  
Kevin R. Bodge ◽  
Robert G. Dean
Keyword(s):  
Sensor Arrays ◽  
Field Research ◽  
Differential Pressure ◽  
Hf Radar ◽  
Absolute Pressure ◽  
Measuring Instruments ◽  
Army Corps ◽  
Engineering Research ◽  
Pressure Transducers ◽  
Directional Wave

The potential error of estimating the small pressure gradient under a directional wave field through the subtraction or comparison of relatively large total-head signals from adjacent pressure transducers in an array is avoided through the use of differential pressure transducers which measure directly the pressure gradients. A device which utilizes four differential pressure tranducers placed orthogonally about one absolute pressure transducer, (the "DPG"), was developed and field-tested at the U.S. Army Corps of Engineers Coastal Engineering Research Center Field Research Facility, Duck, North Carolina. The first five directional Fourier coefficients of the directional ocean spectra were developed from the DPG data, and although no other in_ situ directional wave monitors were available for comparison, the directional peak determined from the DPG agreed well with simultaneous High Frequency (HF) radar data. The DPG instrument is about one-half the size and less than one-sixth the weight of conventional pressure sensor arrays. The field establishment of the orientation of directional-measuring instruments is also discussed.

U.S. Army Coastal Engineering Research Center's Ecology Program

1984 ◽  
Vol 16 (3-4) ◽  
pp. 525-532
Author(s):  
E J Pullen ◽  
P L Knutson ◽  
A K Hurme
Keyword(s):  
Coastal Engineering ◽  
Coastal Vegetation ◽  
Army Corps ◽  
Army Corps Of Engineers ◽  
Engineering Research ◽  
Navigation Channel ◽  
Biological Environment ◽  
Ecology Program ◽  
The U.S ◽  
Shore Erosion

The Coastal Engineering Research Center at Fort Belvoir, Virginia, is responsible for research that supports the U.S. Army Corps of Engineers' Civil Works program. This research involves coastal navigation, channel design and maintenance, storm flooding, shore erosion control, and coastal ecology. The ecology research is focused on two major areas: (1) use of coastal vegetation for engineering purposes and (2) effects of coastal engineering activities on the biological environment. The objectives and accomplishments of the ecology research are discussed and specific examples of field guidance are presented.

Analysis of pulsating flow measurement of engine exhaust by a Pitot tube flowmeter

2005 ◽  
Vol 6 (1) ◽  
pp. 85-93 ◽  
Author(s):  
H Nakamura ◽  
I Asano ◽  
M Adachi ◽  
J Senda
Keyword(s):  
Fast Response ◽  
Differential Pressure ◽  
Pulsating Flow ◽  
Pitot Tube ◽  
Engine Exhaust ◽  
Idle Speed ◽  
Pressure Transducers ◽  
Vehicle Engine ◽  
Before And After ◽  
Response Pressure

The Pitot tube flowmetering technique has been used to measure pulsating flow from a vehicle engine exhaust. In general, flowmetering techniques that utilize differential pressure measurements based on Bernoulli's theory are likely to show erroneous readings when measuring an average flowrate of pulsating flow. The primary reason for this is the non-linear relationship between the differential pressure and the flowrate; i.e. the flowrate is proportional to the square root of the differential pressure. Therefore, an average of the differential pressure does not give an average of pulsating flow. In this study, fast response pressure transducers have been used to measure the pulsating pressure. Then the pulsating differential pressure is converted to the flowrate while keeping the pulsation unaveraged. An average flowrate is then calculated in the flowrate domain in order to maintain linearity before and after averaging. The peak amplitude of a pulsation measured here was about 1800 L/min at an average flowrate of 70 L/min when the engine ran at idle speed. This measurement has been confirmed by measuring the pulsation with a gas analyser. The results show a large amount of back and forth gas movement in the exhaust tube. This magnitude of pulsation can cause as much as five times higher erroneous results with the pressure domain averaging when compared to a flowrate domain averaging.

Effect of sternothyrohyoid myectomy on upper airway mechanics in normal horses

1994 ◽  
Vol 77 (6) ◽  
pp. 2812-2816 ◽  
Author(s):  
S. J. Holcombe ◽  
W. L. Beard ◽  
K. W. Hinchcliff ◽  
J. T. Robertson
Keyword(s):  
Upper Airway ◽  
Face Mask ◽  
Differential Pressure ◽  
Inspiratory Pressure ◽  
O2 Consumption ◽  
Airway Patency ◽  
Pressure Transducers ◽  
Significant Difference ◽  
Airway Mechanics ◽  
Inspiratory Resistance

The effect of transection of the sternothyroideus and sternohyoideus muscles on upper airway mechanics was investigated in exercising horses. Upper airway mechanics of six Standardbred horses were measured at rest and during exercise before and 24 h and 2 wk after sternothyrohyoid myectomy. Transnasal tracheal and pharyngeal catheters connected to differential pressure transducers were used to measure tracheal and pharyngeal pressures. A pneumotachograph mounted on the rostral end of an airtight face mask was used to measure airflow. Horses ran at 50, 75, and 100% of maximal O2 consumption on a treadmill. Twenty-four hours after sternothyrohyoid myectomy, no significant difference was detected in tracheal, pharyngeal, or translaryngeal inspiratory and expiratory pressures and impedances, inspiratory and expiratory flows, and respiratory frequency. Two weeks after sternothyrohyoid myectomy, there was a statistically significant increase in translaryngeal inspiratory pressure (P = 0.035) and tracheal inspiratory pressure (P = 0.032) compared with preoperative measurements. Two weeks after sternothyrohyoid myectomy, there was a statistically significant increase in translaryngeal inspiratory resistance (P = 0.017) and tracheal inspiratory resistance (P = 0.023) compared with preoperative values. Increased translaryngeal and tracheal inspiratory pressures and resistances after sternothyrohyoid myectomy suggest that the sternothyroideus and sternohyoideus muscles act to increase or maintain upper airway patency and stability in normal horses.

scholarly journals Las pruebas estandarizadas como forma de medición del nivel de inglés en la educación Colombiana

2020 ◽  
Author(s):  
Jorge Benavides
Keyword(s):  
Standardized Testing ◽  
Field Research ◽  
Foreign Languages ◽  
Measuring Instruments ◽  
Ministry Of Education ◽  
Testing Procedures ◽  
Level Of Knowledge ◽  
To Come ◽  
Globalized World

This article discusses the importance of standardized testing as a means of assessing learning and determining the level of knowledge and use of foreign languages like English. It is very well known that since the second half of the twentieth century efforts were made in order to come up with valid and reliable measuring instruments for linguistic and communicative competence of a person in foreign languages. This began in the area of field research and ongoing reviewing processes to ensure the quality of testing procedures. Today, in a globalized world with many possibilities for mobility of students, teachers, and researchers standardized tests have been popularized and institutionalized in different countries. Colombia has not been the exception and starting from the beginning of this century the Ministry of Education has implemented the standard promoted by the Common European Framework of Reference for Languages which enables standardized measuring levels of English as a foreign language in students, teachers and professionals in general.

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