According to the theoretical prediction of Paul, it can be concluded that the adsorbed CO2 in these glassy polymers is completely immobilized and does not participate directly in the diffusion. A computer was used in the numerical calculation to determine the true diffusion coefficient from the ...
The CO2-effective diffusion coefficient is a key parameter in the modelling of carbonation of cementitious materials. It is usually deduced from empirical relationships determined by tests on mixtures made with Ordinary Portland Cement (OPC). These relationships are a priori non-valid for materials ...
surface CO2 concentration CA: carbonic anhydrase CAM: Crassulacean acid metabolism CCMs: CO2 concentrating mechanisms CRDS: cavity ringdown spectroscopy D a : diffusion coefficient for CO2 in the gas phase D w : diffusion coefficient for CO2 in the aqueous phase Δ: discrimination against...
摘要CO2在航空燃油中的质量扩散规律对飞机油箱惰化系统的研究极其重要。搭建压力降法实验装置测量CO2在RP-3航空燃油中的扩散系数,实验测试了-20、0、20、40和60℃恒温条件下的CO2气相空间压力随时间变化关系。根据Fick定律建立了容器中二维扩散方程,并采用数值解法,设定
Various models have been developed for the mathematical description and modelling of diffusion. An overview is given e.g. by [54]. Generally, the water vapor diffusion coefficient depends on the actual concrete mix composition, microstructure and boundary conditions (mainly humidity and temperature)....
The binary diffusion coefficient D12 of various substances measured at high dilution in dense CO2 is not describable by the Enskog-Thorne approach. A simplified model potential is presented here, which allows the simulation of the D12 and the thermodynamic properties of the system CO2/C6H6 by ...
It requires only the state point in terms of temperature and pressure (or density) as well as the molecular solute mass as input parameters. First, entropy scaling is applied to estimate the self-diffusion coefficient of CO2. Subsequently, this coefficient is used to determine the infinite ...
D = diffusion coefficient (m2/s) dφ = change in concentration of substance (mass or mol/m3) dx = change in length (m) For simple one-dimensional transport, the diffusion coefficient describes the time–rate of change of concentration . The diffusion coefficient varies from substance to sub...
diffusion coefficient of supercriticalCO2mixtures is proposed. It requires only the state point in terms of temperature and pressure (or density) as well as the molecular solute mass as input parameters. First, entropy scaling is applied to estimate the self-diffusion coefficient ofCO2. Subsequently...
(\Delta\)is the diffusion time.CInitial structures of C6H4BrF inside AFI zeolite. The dark green, white, cyan and dark red balls represent C, H, F and Br atoms, respectively; yellow represents zeolite framework. Self-diffusion coefficient (Ds) for various molecules in the bulk phase byDMD...