1D Air Pressure Fluctuations Cannot Fully Explain the Natural Pressure‐Pumping Effect on Soil Gas Transport

2019 ◽  
Vol 83 (4) ◽  
pp. 1044-1053
Author(s):  
Thomas Laemmel ◽  
Manuel Mohr ◽  
Helmer Schack‐Kirchner ◽  
Dirk Schindler ◽  
Martin Maier
2019 ◽  
Vol 265 ◽  
pp. 424-434 ◽  
Author(s):  
Thomas Laemmel ◽  
Manuel Mohr ◽  
Bernard Longdoz ◽  
Helmer Schack-Kirchner ◽  
Friederike Lang ◽  
...  

2019 ◽  
Vol 16 (16) ◽  
pp. 3197-3205
Author(s):  
Jocelyn E. Egan ◽  
David R. Bowling ◽  
David A. Risk

Abstract. Earth system scientists working with radiocarbon in organic samples use a stable carbon isotope (δ13C) correction to account for mass-dependent fractionation, but it has not been evaluated for the soil gas environment, wherein both diffusive gas transport and diffusive mixing are important. Using theory and an analytical soil gas transport model, we demonstrate that the conventional correction is inappropriate for interpreting the radioisotopic composition of CO2 from biological production because it does not account for important gas transport mechanisms. Based on theory used to interpret δ13C of soil production from soil CO2, we propose a new solution for radiocarbon applications in the soil gas environment that fully accounts for both mass-dependent diffusion and mass-independent diffusive mixing.


2010 ◽  
Vol 42 (3) ◽  
pp. 435-444 ◽  
Author(s):  
Zachary E. Kayler ◽  
Elizabeth W. Sulzman ◽  
William D. Rugh ◽  
Alan C. Mix ◽  
Barbara J. Bond

2021 ◽  
Vol 4 (8(112)) ◽  
pp. 6-15
Author(s):  
Volodymyr Grudz ◽  
Yaroslav Grudz ◽  
Myroslav Iakymiv ◽  
Mykola Iakymiv ◽  
Pavlo Iagoda

Prolonged operation of the gas-transport system in conditions of partial loading involves frequent changes in the volume of gas transportation, which necessitates prompt forecasting of system operation. When forecasting the modes of operation of the gas transport system, the main criterion of optimality implies the maximum volume of gas pumping. After all, in this case, the largest profit of the gas-transport company is achieved under the condition of full provision of consumers with energy. In conditions of incomplete loading of the gas-transport system caused by a shortage of gas supply, optimality criteria change significantly. First, the equipment is operated in ranges far from nominal ones which leads to growth of energy consumption. Secondly, changes in performance cause high-amplitude pressure fluctuations at the outlet of compressor stations. Based on mathematical modeling of nonstationary processes, amplitude and frequency of pressure fluctuations at the outlet of compressor stations which can cause the pipeline overload have been established. To prevent this, it was proposed to reduce initial pressure relative to the maximum one. Calculated dependence was obtained which connects the amplitude of pressure fluctuations with the characteristics of the gas pipeline and the nonstationary process. Reduction in energy consumption for transportation is due to the shutdown of individual compressor stations (CS). Mathematical modeling has made it possible to establish regularities of reduction of productivity of the gas-transport system and duration of the nonstationary process depending on the location of the compressor station on the route. With an increase in the number of shutdown compression stations, the degree of productivity decrease and duration of nonstationarity reduces The established patterns and proposed solutions will improve the reliability of a gas-transport system by preventing pipeline overload and reduce the cost of gas transportation by selecting running numbers of shutdown stations with a known decrease in productivity.


2012 ◽  
Vol 33 (1) ◽  
pp. 127-137 ◽  
Author(s):  
Romuald Mosdorf ◽  
Tomasz Wyszkowski

Chaotic air pressure fluctuations during departure of air bubbles from two neighbouring nozzlesIn the experiment, bubbles were generated from two brass nozzles with inner diameters of 1.1 mm. They were submerged in the glass tank filled with distilled water. There have been measured the air pressure fluctuations and the signal from the laser-phototransistor sensor. For analysis of the pressure signal the correlation (the normalized cross - correlation exponent) and non-linear analyses have been used. It has been shown that hydrodynamic interactions between bubbles can lead to bubble departure synchronization. In this case the bubble departures become periodic. The results of calculation of correlation dimension and the largest Lyapunov exponent confirm that hydrodynamic bubble interactions observed for 4 mm spacing between nozzels cause the periodic bubble departures from two neighbouring nozzles.


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