Competitive electron scavenging of nitrous oxide with sulfur hexafluoride, methyl chloride, and carbon dioxide in liquid neopentane

1974 ◽  
Vol 78 (8) ◽  
pp. 853-855 ◽  
Author(s):  
Kenji Ito ◽  
Yoshihiko Hatano
1972 ◽  
Vol 50 (12) ◽  
pp. 1874-1876 ◽  
Author(s):  
Kenneth R. Harris ◽  
T. N. Bell ◽  
Peter J. Dunlop

Binary diffusion coefficients are reported for the systems He–CO2, He–N2O, and He–SF6. In agreement with the Chapman–Enskog theory the concentration dependence of the diffusion coefficient of each system increases with the mole fraction of the heavier component.


2020 ◽  
Author(s):  
Marianna Linz ◽  
Benjamin Birner ◽  
Alan Plumb ◽  
Edwin Gerber ◽  
Florian Haenel ◽  
...  

<p>Age of air is an idealized tracer often used as a measure of the stratospheric circulation. We will show how to quantitatively relate age to the diabatic circulation and the adiabatic mixing. As it is an idealized tracer, age cannot be measured itself and must be inferred from other tracers. Typically, the two primary trace gases used are sulfur hexafluoride and carbon dioxide. Other tracers have a compact relationship with age, however, and can also be used to calculate age. We will discuss a range of tracer measurements from both satellites and in situ, including sulfur hexafluoride, carbon dioxide, nitrous oxide, methane, and the ratio of argon to nitrogen. We will compare the age derived from these different species, including different calculation methods and caveats, and compare with modeled ideal age and trace gas concentrations. We conclude by showing the strength of the diabatic circulation and the adiabatic mixing calculated from these trace gas calculations.</p>


Measurements have been made of the ultrasonic absorption and the velocity of propagation in a number of liquefied gases at temperatures from 0 to 50°C and over the frequency range 1 to 50 Mc/s. The observations in liquid carbon dioxide cover the major part of a relaxation region, centred about a frequency of approximately 10 Mc/s, and a full analysis is therefore possible in this case. The results are adequately described in terms of a relaxation of the total vibrational specific heat associated with a single relaxation time. For sulphur hexafluoride, nitrous oxide, cyclo propane and methyl chloride it was not possible to cover a substantial part of the relaxation region. In each case, however, the results are consistent with the assumption that the observed non-classical absorption is entirely due to vibrational relaxation and that the total vibrational specific heat relaxes with a single relaxation time. The corresponding characteristic frequencies are calculated and fall within the range 60 to 250 Mc/s. Comparisons are made between the values of the product, density ( ρ ) times relaxation time at constant temperature (ז T ), in the gaseous and liquid states for the above substances and for others, where adequate data is available. It is found that for a given temperature the ratio ( ρז T ) liquid ( ρז T ) gas is greater than, but close to, unity. It is concluded that vibrational transitions in liquids which are not highly associated occur by the mechanism of binary collisions between molecules. The quantity ( ρז T √ T ) –1 , which can be taken as a measure of the collision efficiency, increases with increasing temperature for non-polar liquids, but appears to depend very little on temperature for highly polar ones.


2021 ◽  
Vol 156 ◽  
pp. 108197
Author(s):  
Hollie E. Emery ◽  
John H. Angell ◽  
Akaash Tawade ◽  
Robinson W. Fulweiler

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xue Hao ◽  
Yu Ruihong ◽  
Zhang Zhuangzhuang ◽  
Qi Zhen ◽  
Lu Xixi ◽  
...  

AbstractGreenhouse gas (GHG) emissions from rivers and lakes have been shown to significantly contribute to global carbon and nitrogen cycling. In spatiotemporal-variable and human-impacted rivers in the grassland region, simultaneous carbon dioxide, methane and nitrous oxide emissions and their relationships under the different land use types are poorly documented. This research estimated greenhouse gas (CO2, CH4, N2O) emissions in the Xilin River of Inner Mongolia of China using direct measurements from 18 field campaigns under seven land use type (such as swamp, sand land, grassland, pond, reservoir, lake, waste water) conducted in 2018. The results showed that CO2 emissions were higher in June and August, mainly affected by pH and DO. Emissions of CH4 and N2O were higher in October, which were influenced by TN and TP. According to global warming potential, CO2 emissions accounted for 63.35% of the three GHG emissions, and CH4 and N2O emissions accounted for 35.98% and 0.66% in the Xilin river, respectively. Under the influence of different degrees of human-impact, the amount of CO2 emissions in the sand land type was very high, however, CH4 emissions and N2O emissions were very high in the artificial pond and the wastewater, respectively. For natural river, the greenhouse gas emissions from the reservoir and sand land were both low. The Xilin river was observed to be a source of carbon dioxide and methane, and the lake was a sink for nitrous oxide.


2008 ◽  
Vol 88 (2) ◽  
pp. 163-174 ◽  
Author(s):  
C F Drury ◽  
X M Yang ◽  
W D Reynolds ◽  
N B McLaughlin

It is well established that nitrous oxide (N2O) and carbon dioxide (CO2) emissions from agricultural land are influenced by the type of crop grown, the form and amount of nitrogen (N) applied, and the soil and climatic conditions under which the crop is grown. Crop rotation adds another dimension that is often overlooked, however, as the crop residue being decomposed and supplying soluble carbon to soil biota is usually from a different crop than the crop that is currently growing. Hence, the objective of this study was to compare the influence of both the crop grown and the residues from the preceding crop on N2O and CO2 emissions from soil. In particular, N2O and CO2 emissions from monoculture cropping of corn, soybean and winter wheat were compared with 2 -yr and 3-yr crop rotations (corn-soybean or corn-soybean-winter wheat). Each phase of the rotation was measured each year. Averaged over three growing seasons (from April to October), annual N2O emissions were about 3.1 to 5.1 times greater in monoculture corn (2.62 kg N ha-1) compared with either monoculture soybean (0.84 kg N ha-1) or monoculture winter wheat (0.51 kg N ha-1). This was due in part to the higher inorganic N levels in the soil resulting from the higher N application rate with corn (170 kg N ha-1) than winter wheat (83 kg N ha-1) or soybean (no N applied). Further, the previous crop also influenced the extent of N2O emissions in the current crop year. When corn followed corn, the average N2O emissions (2.62 kg N ha-1) were about twice as high as when corn followed soybean (1.34 kg N ha-1) and about 60% greater than when corn followed winter wheat (1.64 kg N ha-1). Monoculture winter wheat had about 45% greater CO2 emissions than monoculture corn or 51% greater emissions than monoculture soybean. In the corn phase, CO2 emissions were greater when the previous crop was winter wheat (5.03 t C ha-1) than when it was soybean (4.20 t C ha-1) or corn (3.91 t C ha-1). Hence, N2O and CO2 emissions from agricultural fields are influenced by both the current crop and the previous crop, and this should be accounted for in both estimates and forecasts of the emissions of these important greenhouse gases. Key words: Denitrification, soil respiration, rotation, crop residue


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