scholarly journals Study on the Dynamics of Local Pressure Boosting Pneumatic System

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Yan Shi ◽  
Guanwei Jia ◽  
Maolin Cai ◽  
Weiqing Xu
Keyword(s):  
Experimental Study ◽  
Mathematical Models ◽  
Pressure Wave ◽  
Wave Amplitude ◽  
Optimization Method ◽  
Local Pressure ◽  
Pressure System ◽  
Output Pressure ◽  
Pressure Wave Amplitude ◽  
Influence Degree

Local pressure boosting system is a complex and switched system, which is widely used in modern pneumatic systems, to optimize local pressure boosting system; firstly, the basic and the dimensionless mathematical models of the local pressure system were setup. Furthermore, the mathematical models were verified through the experimental study on the local pressure boosting system. Moreover, the influences of the tank’s three main parameters on the performance of local pressure boosting system were studied. It can be seen that the pressure wave amplitude is mainly affected by the dimensionless volume of the tank; its influence degree is 95.1%, and it increases when the later one decreases. The pressure loss of the tank is mainly affected by the dimensionless output pressure, and its influence degree is 68.7%, and it decreases rapidly with the increase of the dimensionless output pressure of the tank. Last, the optimization method of the local pressure boosting system was obtained.

Effect of aging and bolus variables on pharyngeal and upper esophageal sphincter motor function

1993 ◽  
Vol 264 (3) ◽  
pp. G427-G432 ◽  
Author(s):  
R. Shaker ◽  
J. Ren ◽  
B. Podvrsan ◽  
W. J. Dodds ◽  
W. J. Hogan ◽  
...  
Keyword(s):  
Pressure Wave ◽  
Wave Amplitude ◽  
Age Groups ◽  
The Elderly ◽  
Young Group ◽  
Upper Esophageal Sphincter ◽  
Healthy Elderly ◽  
Pressure Wave Amplitude ◽  
Resting Pressure ◽  
Esophageal Sphincter

Effect of aging, bolus volume, temperature, and consistency on the pharyngeal peristalsis, as well as the effect of aging on the upper esophageal sphincter (UES) resting pressure and its response to esophageal distension by air and balloon, were studied in 14 young and 12 healthy elderly volunteers. In both age groups there was no significant volume or temperature effect on amplitude, duration, or velocity of the pharyngeal peristalsis. Compared with water swallows, mashed potato swallows resulted in a significant increase in the amplitude and duration of the hypopharyngeal peristaltic pressure wave (P < 0.05). For water swallows, the amplitude and duration of the peristaltic pressure wave in the hypopharynx were significantly increased in the elderly compared with the young group (P < 0.01). UES resting pressure in the elderly measured 43 +/- 5 (SE) mmHg and was significantly less than that of the young (71 +/- 8 mmHg; P < 0.01). Magnitude of the UES pressure decrease because of esophageal distension by air, as well as magnitude of its pressure increase because of esophageal balloon distension, was similar among young and elderly. 1) Contrary to common expectations, the parameters of the pharyngeal peristaltic pressure wave do not deteriorate in the elderly in their seventh and eighth decade. 2) Compared with the young, hypopharyngeal pressure wave amplitude and duration are significantly increased in the elderly. This increase could be caused by an adaptation response to a pharyngeal outflow compromise. 3) Pharyngeal peristaltic pressure wave amplitude and duration, but not its velocity, are modulated by the bolus consistency. This modulatory mechanism is preserved in the elderly. 4) Although UES resting pressure is significantly decreased in the elderly, its pressure response to esophageal distension by air and balloon is preserved.

Relationships between spatial patterns of colonic pressure and individual movements of content

2000 ◽  
Vol 278 (2) ◽  
pp. G329-G341 ◽  
Author(s):  
Ian J. Cook ◽  
Yoshiyuki Furukawa ◽  
Voula Panagopoulos ◽  
Peter J. Collins ◽  
John Dent
Keyword(s):  
Regional Variation ◽  
Pressure Wave ◽  
Healthy Subjects ◽  
Wave Amplitude ◽  
Distal Colon ◽  
Pressure Waves ◽  
Sulfur Colloid ◽  
Pressure Wave Amplitude ◽  
The Relationship ◽  
Colonic Content

The aim of this study was to examine the relationship between colonic pressure waves and movement of content. In 11 healthy subjects, pressures were recorded at 10-cm intervals from cecum to rectum for 32 h. In six subjects, transit was simultaneously measured for 8 h after direct cecal instillation of 1.5 mCi of 99mTc sulfur colloid. Thirty-two percent of isotope movements were related to nonpropagating activity and twenty-eight percent to propagating sequences. The extent of isotope movement related to propagating sequences (25.1 ± 2.1 cm) was greater than that due to nonpropagating activity (12.8 ± 0.7 cm; P = 0.0001). Propagating sequences originated significantly more frequently ( P = 0.004) and propagated further ( P = 0.0006) in the proximal compared with the distal colon. Only 36% of propagating sequences were propulsive of content, and compared with nonpropulsive sequences, these propagated further (41 ± 6 vs. 27 ± 2 cm; P < 0.05) and had a higher probability of originating proximally ( P = 0.0003), a higher pressure wave amplitude (50 ± 5 vs. 34 ± 4 mmHg; P = 0.0001), and slower velocity (2.2 ± 0.3 vs. 3.6 ± 0.47 cm/s; P = 0.02). We conclude that most movements of colonic content are related to pressure waves. There is marked regional variation in the prevalence, velocity, and extent of propagation of propagating pressure wave sequences, which are an important mechanism for transporting content over long distances. The effectiveness of transport by a propagating sequence is influenced by its site of origin, amplitude, and velocity.

scholarly journals Intracranial Pressure vs Intracranial Pressure-Wave Amplitude

Neurosurgery ◽  
2012 ◽  
Vol 71 (2) ◽  
pp. E523-E524
Author(s):  
Alisson Roberto Teles ◽  
Paulo Roberto Franceschini ◽  
Jorge Luiz Kraemer
Keyword(s):  
Intracranial Pressure ◽  
Pressure Wave ◽  
Wave Amplitude ◽  
Pressure Wave Amplitude

scholarly journals AN EXPERIMENTAL STUDY ON SAND DUNE SEDIMENT TRANSPORT DUE TO TSUNAMI OVERWASH

2017 ◽  
pp. 15
Author(s):  
K M Ahtesham Hossain Raju ◽  
Shinji Sato
Keyword(s):  
Experimental Study ◽  
Sediment Transport ◽  
Mathematical Models ◽  
Storm Surge ◽  
Laboratory Study ◽  
Sand Dune ◽  
Small Scale ◽  
Data Set ◽  
Grain Sizes ◽  
Dry Sand

Response of sand dune when overwashed by tsunami or storm surge, is investigated by conducting small scale laboratory study. Dune consisting of initially wet sand and initially dry sand are tested for three different sand grain sizes. Overtopping of water and the corresponding sediment transport are analyzed. These data set can be used to validate mathematical models associated with dune sediment transport as well as prediction of dune profile.

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