Low Pressure Flow of Gases

1964 ◽  
Vol 68 (10) ◽  
pp. 3087-3088 ◽  
Author(s):  
H. J. M. Hanley ◽  
W. A. Steele
Keyword(s):  
Low Pressure ◽  
Pressure Flow

Rotational energy transfer on a hot surface in a low-pressure flow studied by CARS

1991 ◽  
Vol 258 (1-3) ◽  
pp. A604
Author(s):  
N. Herlin ◽  
M. Pealat ◽  
M. Lefebvre ◽  
P. Alnot ◽  
J. Perrin
Keyword(s):  
Energy Transfer ◽  
Low Pressure ◽  
Rotational Energy ◽  
Pressure Flow ◽  
Rotational Energy Transfer ◽  
Hot Surface

The Port Width and Position Determination for Pressure-Exchange Ejector

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Wenjing Zhao ◽  
Dapeng Hu ◽  
Peiqi Liu ◽  
Yuqiang Dai ◽  
Jiupeng Zou ◽  
...  
Keyword(s):  
High Pressure ◽  
Performance Optimization ◽  
Pressure Ratio ◽  
Low Pressure ◽  
Operating Conditions ◽  
Maximum Deviation ◽  
Dimensionless Time ◽  
Pressure Flow ◽  
Outlet Pressure ◽  
Pressure Exchange

A pressure-exchange ejector transferring energy by compression and expansion waves has the potential for higher efficiency. The width and position of each port are essential in pressure-exchange ejector design. A dimensionless time τ expressing both port widths and the positions of port ends was introduced. A prototype was designed and the experimental system was set up. Many sets of experiment with different geometrical arrangements were conducted. The results suggest that the efficiency greatly changes with the geometrical arrangements. The efficiency is about 60% at proper port widths and positions, while at improper geometrical arrangements, the efficiency is much lower and the maximum deviation may reach about 20%. The proper dimensionless port widths and positions at different operating conditions are obtained. For a fixed overall pressure ratio, the widths of the high pressure flow inlet and middle pressure flow outlet increase as the outlet pressure increases and the low pressure flow inlet width is reduced with a larger outlet pressure. The middle pressure flow outlet (MO) opening end remains constant at different outlet pressures. The positions of the high pressure flow inlet (HI) closed end and the low pressure flow inlet (LI) open end increase with the elevation of outlet pressure, however, the distance between the HI closing end and the LI opening end is constant. The port widths and positions have a significant influence on the performance of the pressure-exchange ejector. The dimensionless data obtained are very valuable for pressure-exchange ejector design and performance optimization.

Role of adenosine in coronary autoregulation

1986 ◽  
Vol 250 (4) ◽  
pp. H558-H566 ◽  
Author(s):  
F. L. Hanley ◽  
M. T. Grattan ◽  
M. B. Stevens ◽  
J. I. Hoffman
Keyword(s):  
Steady State ◽  
Adenosine Deaminase ◽  
Low Pressure ◽  
Catalytic Subunit ◽  
Coronary Resistance ◽  
Pressure Flow ◽  
Intracoronary Infusion ◽  
Adenosine Concentration ◽  
Anesthetized Dogs

The role of cardiac interstitial adenosine as an important metabolite in coronary autoregulation has not been established. We therefore measured steady-state cardiac interstitial adenosine concentration at a high and a low coronary inflow pressure using an epicardial diffusion well in anesthetized dogs. Although coronary resistance for the high and low pressure points showed highly significant differences (P less than 0.001), adenosine averaged 302 +/- 98 and 286 +/- 91 (SD) pmol/ml for the high and low pressure points, respectively (P greater than 0.20). Cardiac interstitial adenosine concentration was then measured with and without an intracoronary infusion of adenosine deaminase catalytic subunit. Adenosine averaged 28 +/- 21 (SD) pmol/ml during the infusion compared with 281 +/- 68 during control conditions (P less than 0.001). Finally, pressure-flow relations were obtained with and without the adenosine deaminase infusion, and there was no loss of autoregulation in the pressure of adenosine deaminase. These findings indicate that intracoronary adenosine deaminase markedly reduces interstitial adenosine concentration, that cardiac interstitial adenosine concentration remains constant during autoregulation, and that the coronary bed autoregulates normally when interstitial adenosine is reduced to levels close to zero. We conclude that cardiac interstitial adenosine concentration is not an important component in coronary autoregulation.

Gasphasen-Reaktionen, 58 [1, 2] β-Chlorethylazid: HCl-Eliminierung und Pyrolyse / Gas Phase Reactions, 58 [1, 2] β-Chloroethyl Azide: HCl Elimination and Pyrolysis

1987 ◽  
Vol 42 (3) ◽  
pp. 301-307 ◽  
Author(s):  
Hans Bock ◽  
Ralph Dammel
Keyword(s):  
Real Time ◽  
Gas Phase ◽  
Flow System ◽  
Chemical Activation ◽  
Thermolysis Product ◽  
Low Pressure ◽  
Gas Analysis ◽  
Gas Phase Reactions ◽  
Pressure Flow ◽  
By Products

The HCl elimination from β-chloroethyl azide (1-azido-2-chloroethane) over potassium tert. butanolate at 350 K in a low pressure flow system is optimized using PE spectroscopic real-time gas analysis. The highly explosive vinyl azide formed can be purified by cool-trapping the by-products. Its subsequent and virtually hazard-free pyrolysis yields 2H-azirine, which can be isolated at temperatures below 240 K.In contrast, the direct pyrolysis of β-chloroethyl azide requires temperatures above 710 K and results in a simultaneous split-off of both HCl and N2, yielding acetonitrile as the main thermolysis product. No intermediates such as β-chloroethanimine or ketenimine are observed, a result which is interpreted in terms of chemical activation

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