Leaching of phenol from spilled bitumen into flowing aquifer poses an environmental threat to groundwater contamination. A two‐dimensional model with de‐coupled transfer was built to model phenol propagation in the flowing stream. The model predicted that the produced phenol concentration monitored at an observation well would rise sharply and then decline gradually as the phenol flux emerging from the bitumen surface was depleted with time. The model is useful in estimating the size of the spill, produced phenol concentration, phenol spatial distribution and the time required for the phenol concentration to decline to an environmentally acceptable level. It is well suited to other water pollution problems with chemical spills. 相似文献
2D, 3D chloride ion concentration at the edge and corner zones were systematically investigated for fly ash concretes made
with different cement replacement percentage by fly ash (0%, 10%, 20%, 40%, 60%), water to binder ratios (0.3, 0.35, 0.4),
and curing ages (28 d, 90 d). An interaction effect caused by 2D and 3D diffusion could obviously be observed through the
comparison with 1D testing results. In order to quantify the interaction effect, 2D and 3D diffusion interaction coefficients
was proposed in this paper. Finally, the changes of 2D and 3D interaction coefficients with the change in the free chloride
ion concentration were given. The above research provide an insight into chloride ion attack on the edge and corner reinforcing
bars of concrete structures in the field of civil engineering. 相似文献
A commonly used nylon 6 two‐step VK tubular reactor is simulated in this work. To verify the reliability of the model, careful comparison with results obtained on different continuous plants is made. The effect of various conditions and parameters, e.g. feed composition, temperature, pressure, etc. on the product properties such as caprolactam conversion, degree of polymerization (DP), dimer, integral heat and their distribution index is studied. It is observed that the caprolactam conversion and DP of the product may be affected by various conditions in the first stage and the temperature profile at the top of the second stage, but they finally reach the equilibrium values if the residence time is long enough. The most effective way to increase DP of the product is to increase the vacuum at the top of the second stage.
CPL conversion and DP profile for pressure of tube 2: 0.032, 0.037, 0.042 mPa; other parameters as given for example A of Table 5 . 相似文献