Nitrous residence time

The concentration of nitrous oxide (N20) in the atmosphere is only about 0.30 ppm but it increases by about 0.2% per year and so is at least partly of anthropogenic origin. Nitrous oxide is a product of the degradation of nitrate fertilizers, but some 7 x 105 tonnes of N2O are released annually to the atmosphere during production of nylon.20 The residence time of N20 in the atmosphere is about 150 years, and it could in the future contribute up to 10% of the anticipated greenhouse warming. 

Nitrous oxide (N20) is produced by bacteria in the natural denitrification process. It is chemically inert in the troposphere, but in the stratosphere it is degraded photochemically. The average concentration of N20 in the troposphere is about 300 ppb, and its residence time there is 10 years. What is the global rate of production of N20 in units of kg/ year Assume that the volume of the stratosphere (at 0°C and 1 atm) is 10% that of the atmosphere. 

These reaction rates are too low to explain the appreciable extraction of neptunium obtained in the short-residence-time HA contactors used at Hanford and elsewhere. Swanson [S24] reported that radiolysis reaction products of TBP and nitric acid present in Purex solutions increased the neptunium oxidation rate and provided a possible explanation. He found that the oxidation rate could be increased several orders of magnitude by adding a synthetic rate-accelerating material (RAM) produced by reacting the aciform of nitropropane, CjHs(CH)(NO)(OH), with nitric and nitrous acids, and recommended addition of such a catalyst to Purex feed if increased neptunium extraction were desired. 

Like methane and nitrous oxide, tropospheric ozone is a natural greenhouse gas, but one which has a short tropospheric residence time. Ozone s bending vibration occurs at 14.2 pm, near that for CO2, and thus it does not contribute much to the enhancement of the greenhouse effect since atmospheric carbon dioxide already removes much of the outgoing light in this wavelength. 

The byproducts that have been observed for SNCR are ammonia, carbon monoxide, and nitrous oxide. All three byproducts are minimized when the temperature is on the high side of the window and residence time is relatively long. Ammonia is a concern because of the possibility of forming ammonium salts (sulfate, bisulfate, and chloride). These salts can foul backend heat exchange equipment or form visible... 

Analyte Atomization and Ionization Figure 10-4 shows temperatures in the plasma using isothermal contours. Sample atoms reside in the plasma for about 2 ms before they reach the observation point. During the residence time they experience temperatures ranging from 5500 to 80(X) K. The time and temperatures are roughly two to three times greater than those found in the hottest combustion flames (acetylene-nitrous oxide) used in flame spectroscopic methods. As a result, atomization is more complete in... 

As nitrous oxide (N2O) does not react in the troposphere, it will have a long tropospheric residence time and reach the stratosphere where its oxidation leads to the formation of NO and NO2. These gases appear in catalytic cycles of reactions leading to less ozone above 25 km and more ozone below this altitude [15]. 

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