Long Range Concentration Gradients at the Free Surface of Polymer Films Swollen by Carbon Dioxide

2008 ◽  
Vol 41 (23) ◽  
pp. 9306-9311 ◽  
Author(s):  
Xinxin Li ◽  
Bryan D. Vogt
2021 ◽  
Vol 154 ◽  
pp. 106202
Author(s):  
Polina S. Kazaryan ◽  
Maria A. Agalakova ◽  
Elena P. Kharitonova ◽  
Marat O. Gallyamov ◽  
Mikhail S. Kondratenko

2006 ◽  
Vol 503-504 ◽  
pp. 433-438 ◽  
Author(s):  
Xavier Sauvage

Concentration gradients resulting from long range diffusion during Severe Plastic Deformation (SPD) have been investigated with the 3D Atom Probe technique (3D-AP). First, in a pearlitic steel where alloying elements (Mn, Si and Cr) are partitioned between the ferrite and carbides in the non-deformed state. After processing by High Pressure Torsion (HPT), they are homogeneously distributed in the nanostructure, indicating that long range diffusion occurred along with the dissolution of carbides. 3D-AP data of a Cu-Fe composite processed by HPT show as well a significant interdiffusion of Cu and Fe, probably promoted by additional vacancies. On the basis of these experimental data, and using the theory described for irradiated materials, vacancy fluxes and vacancy production rates were estimated assuming that new vacancies are continuously produced and eliminated on grain boundaries.


2018 ◽  
Vol 176 ◽  
pp. 05045 ◽  
Author(s):  
Erwan Cadiou ◽  
Jean-Baptiste Dherbecourt ◽  
Guillaume Gorju ◽  
Jean-Michel Melkonian ◽  
Antoine Godard ◽  
...  

We report on ground-based atmospheric concentration measurements of carbon dioxide, using a pulsed direct detection differential absorption lidar operating at 2051 nm. The transmitter is based on a tunable parametric source emitting 10-mJ energy, 10-ns duration Fourier-limited pulses. Range resolved concentration measurements have been carried out on the aerosol back-scattered signal. Cloud signals have been used to get long range integrated-path measurements.


In an appendix to a paper on the static diffusion of gases, communicated to the Society in 1900, it was shown that when a current of air containing a constant proportion of carbon dioxide is caused to move in a turbulent stream over the free surface of a solution of caustic alkali, the rate of absorption of that gas increases with the velocity of the air-current up to a certain optimal speed, beyond which no further increase in the speed of the current influences the rate of absorption. It was further shown that when the optimal velocity of the air-current has been reached, and the temperature is maintained practically constant, the rate of absorption then varies directly as the partial pressure of the carbon dioxide in the air. In other words, if under the above conditions the rate of absorption per unit of area of the liquid surface is a for a partial pressure of carbon dioxide represented by and is for a partial pressure of p' , then at similar temperatures, a / p = a' / p' . A suggestion was also made that this principle might be found applicable to a determination of the carbon dioxide in air, and that if the method were found to be a practical one it would have the manifest advantage of not requiring any measurement of the air from which the gas was absorbed.


1985 ◽  
Vol 28 (2) ◽  
pp. 60-66
Author(s):  
John Lemons

The combustion of fossil fuels increases atmospheric levels of carbon dioxide. This may cause a long-term warming of the atmosphere. Solutions to the carbon dioxide problem are particularly difficult because adverse effects will be felt by future generations, but remedial action and sacrifices must be made by present generations. Decisions regarding the problem which affect both the immediate and long-range future must be made deliberately or by default in perhaps only 15-20 years, before we are reasonably confident with our knowledge of the problem and before we know whether it will, in fact, occur. Much of the uncertainty involves projections of future energy use, and scientific knowledge of the carbon cycle and the environment.


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