A Hydrodynamic Mechanism for Autoregulation of Flow

Cardiology ◽  
1966 ◽  
Vol 48 (6) ◽  
pp. 532-535 ◽  
Author(s):  
S. Rodbard
Keyword(s):  
Hydrodynamic Mechanism ◽  
Autoregulation Of Flow

Note. Vacuum impregnation of banana (Musa acuminata cv. giant cavendish) / Nota. Impregnación a vacío de banana (Musa acuminata cv. giant cavendish

1998 ◽  
Vol 4 (2) ◽  
pp. 127-131 ◽  
Author(s):  
R. Sousa ◽  
D. Salvatori ◽  
A. Andrés ◽  
P. Fito
Keyword(s):  
Structural Changes ◽  
Musa Acuminata ◽  
Diameter Ratio ◽  
Dynamic Mechanism ◽  
Vacuum Impregnation ◽  
Local Market ◽  
Relaxation Phenomena ◽  
Pressure Gradients ◽  
Hydrodynamic Mechanism

Vacuum impregnation of banana was analysed by a hydrodynamic mechanism to determine effec tive porosity ( ∈e). In the initial experiments, the influence of the ripening degree and cut was deter mined without taking into account sample deformations caused by the pressure gradients; in these cases ∈ e decreased as maturity progressed. Important structural changes were observed 2-4 days after the bananas were purchased from the local market, probably due to the climacteric charac teristic of the product. Other experiments were carried out to analyse the coupling of the hydro dynamic mechanism (HDM) with deformation-relaxation phenomena (DRP) by varying the time of treatment; ε e values determined by this procedure were approximately 10.1% and significant deformation values in the vacuum step (γ e = 3.6%) were observed. The height/diameter ratio also seemed to influence the behaviour of the product to the HDM-DRP action. The most impregnated samples were the ones with a height half that of the banana diameter.

scholarly journals Physio-chemical hydrodynamic mechanism underlying the formation of thin adsorbed boundary films

2012 ◽  
Vol 156 ◽  
pp. 123 ◽  
Author(s):  
W. W. F. Chong ◽  
M. Teodorescu ◽  
H. Rahnejat
Keyword(s):  
Hydrodynamic Mechanism ◽  
Boundary Films

scholarly journals Head Drop of a Spatial Turbopump Inducer

2008 ◽  
Vol 130 (11) ◽  
Author(s):  
Nellyana Gonzalo Flores ◽  
Eric Goncalvès ◽  
Regiane Fortes Patella ◽  
Julien Rolland ◽  
Claude Rebattet
Keyword(s):  
Power Efficiency ◽  
Flow Analysis ◽  
Numerical Results ◽  
Good Prediction ◽  
Local Flow ◽  
Local Study ◽  
Blade Loading ◽  
Hydrodynamic Mechanism ◽  
Global And Local ◽  
Vapor Liquid

A computational fluid dynamics model for cavitation simulation was investigated and compared with experimental results in the case of a three-blade industrial inducer. The model is based on a homogeneous approach of the multiphase flow coupled with a barotropic state law for the cool water vapor/liquid mixture. The numerical results showed a good prediction of the head drop for three flow rates. The hydrodynamic mechanism of the head drop was investigated through a global and local study of the flow fields. The evolution of power, efficiency, and the blade loading during the head drop were analyzed and correlated with the visualizations of the vapor/liquid structures. The local flow analysis was made mainly by studying the relative helicity and the axial velocity fields. A first analysis of numerical results showed the high influence of the cavitation on the backflow structure.

Effect of aminophylline on hindlimb blood flow autoregulation during increased metabolism in dogs

1986 ◽  
Vol 60 (6) ◽  
pp. 1857-1864 ◽  
Author(s):  
P. J. Metting ◽  
D. L. Weldy ◽  
T. F. Ronau ◽  
S. L. Britton
Keyword(s):  
Blood Flow ◽  
Closed Loop ◽  
Perfusion Pressure ◽  
Treadmill Exercise ◽  
Receptor Site ◽  
External Iliac Artery ◽  
Flow Probe ◽  
Pressure Flow ◽  
Occlusion Cuff ◽  
Autoregulation Of Flow

The contribution of adenosine to hindlimb blood flow autoregulation during treadmill exercise or the administration of 2,4-dinitrophenol (DNP) was evaluated in 9 conscious dogs by determining hindlimb vascular bed pressure-flow relationships in the presence and absence of the adenosine receptor site antagonist, aminophylline. Hindlimb pressure-flow relationships were obtained by measuring blood flow during stepwise reductions in perfusion pressure produced with an occlusion cuff located distal to a flow probe on the external iliac artery. The efficiency of autoregulation was quantitated by calculating the closed-loop gain of flow regulation (Gc) at each pressure decrement utilizing the equation Gc = 1 - (% delta flow/% delta pressure). A Gc of one represents perfect autoregulation of flow, and a Gc of zero is indicative of a rigid system. During exercise, Gc averaged 0.44 +/- 0.07. Aminophylline reduced the Gc during exercise to -0.07 +/- 0.06 (P less than 0.05). During DNP administration, Gc averaged 0.54 +/- 0.09 and declined to -0.09 +/- 0.10 in the presence of aminophylline (P less than 0.05). These results support the hypothesis that adenosine is a primary mediator of hindlimb blood flow autoregulation during conditions that increase hindlimb metabolism.

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