scholarly journals Evidence for deep gas loss in open volcanic systems

2021 ◽  
Vol 83 (2) ◽  
Author(s):  
Marielle Collombet ◽  
Alain Burgisser ◽  
Mathieu Colombier ◽  
Elizabeth Gaunt
Keyword(s):  
Gas Loss

scholarly journals GAS LOSS BY RAM PRESSURE STRIPPING AND INTERNAL FEEDBACK FROM LOW-MASS MILKY WAY SATELLITES

2016 ◽  
Vol 826 (2) ◽  
pp. 148 ◽  
Author(s):  
Andrew Emerick ◽  
Mordecai-Mark Mac Low ◽  
Jana Grcevich ◽  
Andrea Gatto
Keyword(s):  
Milky Way ◽  
Internal Feedback ◽  
Ram Pressure ◽  
Low Mass ◽  
Gas Loss

Self-preservation Effect of Gas Hydrates

2021 ◽  
Vol 23 ◽  
pp. 346-355
Author(s):  
Anatoliy Pavlenko
Keyword(s):  
Gas Hydrates ◽  
Gas Hydrate ◽  
Experimental Studies ◽  
Interphase Surface ◽  
Quantitative Characteristics ◽  
Nonequilibrium Conditions ◽  
Water Simulation ◽  
Gas Loss ◽  
Physical And Mathematical Models ◽  
And Storage

This work was performed to improve the storage and transportation technology of gas hydrates in nonequilibrium conditions. At atmospheric pressure and positive ambient temperature, they gradually dissociate into gas and water. Simulation of the gas hydrate dissociation will determine optimal conditions for their transportation and storage, as well as minimize gas loss. Thermodynamic parameters of adiabatic processes of forced preservation of pre-cooled gas hydrate blocks with ice layer were determined theoretically and experimentally. Physical and mathematical models of these processes were proposed. The scientific novelty is in establishing quantitative characteristics that describe the gas hydrates thermophysical parameters thermophysical characteristics influence on the heat transfer processes intensity on the interphase surface under conditions of gas hydrates dissociation. Based on the results of experimental studies, approximation dependences for determining the temperature in the depths of a dissociating gas hydrate array have been obtained. Gas hydrates dissociation mathematical model is presented.

scholarly journals Study on Change Rules of Factors Affecting Gas Loss during Coalbed Air Reverse Circulation Sampling

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Demin Chen ◽  
Wei Long ◽  
Yanyan Li ◽  
Rui Zhang
Keyword(s):  
Particle Size ◽  
Sharp Decrease ◽  
Experimental System ◽  
Gas Content ◽  
Impact Factors ◽  
Extreme Pressure ◽  
Factors Affecting ◽  
Reverse Circulation ◽  
Gas Loss ◽  
Skew Distribution

The gas loss in sampling is the root of coalbed gas content measurement error. The pressure and particle size have a significant impact on the gas loss. Using the self-developed coal particle pneumatic pipeline transportation experimental system, this study investigated the pressure and particle size changes in the sampling pipeline. It is found that the sampling process can be divided into four stages: no flow field stage, sample outburst stage, stable conveying stage, and tail purging stage. The extreme pressure in the sampling pipeline appears at the sample outburst stage; and the pressure in the pipeline has levelled off after sharp decrease in the stable conveying stage. It is also found that the extreme pressure increases first and then decreases with the increase of particle size. The duration of outburst stage is negatively correlated with particle size, and that of stable conveying stage is positively correlated with particle size. In addition, the results show that the loss rate of 1–3 mm particles is the smallest after the test but that particles less than 1 mm increase by about two times and particles greater than 3 mm decrease by more than three times. The study also shows that the particle size distribution of coal samples is a single peak with left skew distribution, and the gas reverse circulation sampling test does not change the location of the peak but makes it higher and sharper. The single size coal sample is more likely to collide than the mixture. This study can help to advance the understanding of impact factors on gas loss during reverse circulation sampling.

Influence of transport on gas loss from freight containers under fumigation. Part I: Experimental investigation

1986 ◽  
Vol 17 (3) ◽  
pp. 207-220 ◽  
Author(s):  
H. Jonathan Banks ◽  
Alister K. Sharp ◽  
Arthur R. Irving
Keyword(s):  
Experimental Investigation ◽  
Gas Loss

Sounding Response of the Kokanee and Sockeye Salmon

1968 ◽  
Vol 25 (6) ◽  
pp. 1115-1131 ◽  
Author(s):  
H. H. Harvey ◽  
W. S. Hoar ◽  
C. R. Bothern
Keyword(s):  
Sockeye Salmon ◽  
Bladder Wall ◽  
Muscle Fibers ◽  
Circular Muscle ◽  
Adrenergic Blockade ◽  
Kokanee Salmon ◽  
Associated Gas ◽  
Treated Fish ◽  
Gas Loss ◽  
Adrenergic Blocking

When frightened, sockeye and kokanee salmon dive into deeper waters. This is termed the "sounding response."The sounding response in these fish is accompanied by the expulsion of gas from the swimbladder via the pneumatic duct. This gas loss is active and results from the contraction of the circular muscle fibers in the wall of the swimbladder.Gas loss on sounding is reduced or obviated after exposure to adrenergic blocking agents and enhanced in fish treated with sympathomimetics. Circular muscle fibers in intact and isolated strips of swimbladder contracted in response to sympathomimetics, but this response was prevented after adrenergic blockade. These results suggest the concentration of the swimbladder and associated gas expulsion is under adrenergic control.In untreated fish, an average pressure of 28.1 mm Hg was required to force gas out of the swimbladder through the pneumatic duct. In antropine-treated fish this duct-release pressure fell to an average of 0.2 mm Hg. This suggests constriction of the pneumatic duct is under cholinergic control.Histologically, the pneumatic duct was continuous with the oesophagus and extended as a convoluted duct to the anterior end of the swimbladder. Smooth muscle fibers surrounded the duct along its length and some striated fibers were present at the point where the duct joined the oesophagus. Occlusion of the pneumatic duct may be through the contraction of either of these types of fibers.The term "Gasspuckreflex" as originally used by Franz described the loss of gas from the swimbladder of physostomes in response to decompression. The authors suggest this term be reserved for this passive loss of gas, and not applied to fright-induced gas loss, resulting from active contraction of the bladder wall.

scholarly journals CO-driven activity constrains the origin of comets

2020 ◽  
Vol 636 ◽  
pp. L3 ◽  
Author(s):  
M. Fulle ◽  
J. Blum ◽  
A. Rotundi
Keyword(s):  
Loss Rate ◽  
Dust Particles ◽  
Mass Ratio ◽  
Cometary Nuclei ◽  
Nucleus Surface ◽  
Activity Onset ◽  
Gas Loss ◽  
Open Question ◽  
Comet 67P ◽  
Co Gas

Context. An open question in the study of comets is the so-called cohesion bottleneck, that is, how dust particles detach from the nucleus. Aims. We test whether the CO pressure buildup inside the pebbles of which cometary nuclei consist can overcome this cohesion bottleneck. Methods. A recently developed pebble-diffusion model was applied here to comet C/2017K2 PANSTARRS, assuming a CO-driven activity. Results. (i) The CO-gas pressure inside the pebbles erodes the nucleus into the observed dust, which is composed of refractories, H2O ice and CO2 ice. (ii) The CO-driven activity onset occurs up to heliocentric distances of 85 au, depending on the spin orientation of the comet nucleus. (iii) The activity onset observed at ≈26 au suggests a low obliquity of the nucleus spin axis with activity in a polar summer. (iv) At 14 au, the smallest size of the ejected dust is ≈0.1 mm, consistent with observations. (v) The observed dust-loss rate of ≈200 kg s−1 implies a fallout ≥30%, a nucleus surface active area ≥10 km2, a CO-gas loss rate ≥10 kg s−1, and a dust-to-gas ratio ≤20. (vi) The CO-driven activity never stops if the average refractory-to-all-ices mass ratio in the nucleus is ≤4.5 for a nucleus all-ices-to-CO mass ratio ≈4, as observed in comets Hale–Bopp and Hyakutake. These results make comet C/2017K2 similar to the Rosetta target comet 67P/Churyumov–Gerasimenko. (vii) The erosion lifetime of cometary planetesimals is a factor 103 shorter than the timescale of catastrophic collisions. This means that the comets we observe today cannot be products of catastrophic collisions.

scholarly journals Ram Pressure Stripping of Spiral Galaxies in Clusters

2004 ◽  
Vol 217 ◽  
pp. 376-381
Author(s):  
Elke Schumacher ◽  
Gerhard Hensler
Keyword(s):  
Mass Loss ◽  
Spiral Galaxies ◽  
Disk Galaxies ◽  
Helmholtz Instability ◽  
Restoring Force ◽  
Ram Pressure ◽  
First Results ◽  
Two Phases ◽  
Gas Loss ◽  
Long Timescales

We investigate the process of ram pressure stripping by means of numerical simulations with a 2D hydrodynamical code. We present some first results of a set of simulations with varying galaxy velocities and ICM densities. We find that in typical cluster core environments disk galaxies lose a substantial amount of their gas, whereas in the outskirts of galaxy clusters the mass loss is quite small. Furthermore, the gas loss happens in two phases: In the initial phase gas is pushed out of regions where the ram pressure overcomes the gravitational restoring force; most of the overall gas loss happens in this phase. Afterwards the Kelvin-Helmholtz instability leads to a further mass loss at a small rate, that could be important on long timescales.

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