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Traditional dyeing usually consumes a significant amount of water and salts, thus causing environmental pollution. Salt-free and low-water dyeing has become an important research direction in the cotton fabric dyeing industry. The non-aqueous media dyeing technology, using decamethylcyclopentasiloxane (D5) as the dyeing medium, has achieved energy saving and emission reduction in this industry. To investigate the influence of inorganic salts on the dyeing properties of reactive dyes in a non-aqueous medium dyeing system, the adsorption kinetics and level dyeing property of C.I. Reactive Red 120 were investigated at various concentrations of sodium sulfate. When no salts were included in the siloxane non-aqueous dyeing system, 80% of the reactive dye could diffuse onto the cotton fabric surface after 10 min. However, if 13% salts were added during dyeing, 87% of the reactive dye could diffuse to cotton fabric surface over the same amount of time. Moreover, the adsorption rate of dye was increased from 3.85 mg/g·min to 5.04 mg/g·min when the quantity of salts was increased from 0% to 13%. However, the concentration of sodium sulfate had minimal effect on the color depth of the dyed fabric and the final uptake of dye. But, when the concentration of sodium sulfate was significant, the level dyeing property of the dye became poor as the Sγ(λ) value was increased from 0.020 to 0.042. The adsorption kinetic of C.I. Reactive Red 120 in D5 dyeing solution may be best described by the pseudo-second-order kinetic model. As the sodium sulfate concentration increases, the half-dyeing time gradually decreases and the adsorption rate of dye increases. The repulsive force between the dye and the cotton fiber was lowered by the addition of sodium sulfate. Consequently, in the D5 dyeing system, the level dyeing property of reactive dye may be affected by the adsorption rate. Therefore, the formula of reactive dyes that do not contain salts can be applied successfully in non-aqueous dyeing systems.

A complete stress determination has been performed by hydraulic tests on pre-existing fractures conducted in two inclined boreholes for a railway cavern in Hong Kong, China. A total of ten complete tests including normal stress and fracture plane orientation determination have been successfully carried out in the zone where the cavern is located. The test depth in two holes varies from 101 to 120 m beneath the ground surface. After a brief introduction to the test system, procedures, and results in this paper, the inversion method for in situ stress field, neglecting both the vertical and horizontal stress gradient, is reported. Moreover, the genetic algorithm is applied to search for the optimal solution, which minimizes the misfit function, and the misfit associated with this solution is used to evaluate the 90 % confidence level domain with the Monte Carlo Technique. The results of this study are useful for a better understanding of the stress level of the planned railway cavern and also helpful for the safety design of the cavern.

This technical note summarizes and discusses the results of the in situ stress measurements by hydraulic fracturing conducted in 7 holes at depths ranging from 21 to 111 m in planned dam sites, and in 13 holes at depths varying from 28 to 532 m in planned tunnel sites in the Western Route of South to North Water Transfer Project in China. The measured maximum and minimum horizontal principal stresses increase linearly with depth in tunnel sites, and piecewise-linearly in dam areas. The horizontal stresses are greater than the vertical stress, indicating a thrust faulting regime at all tested locations. Such a stress regime is confirmed by local geological structures. The direction of the maximum horizontal principal stress is generally NEE–SWW, which is highly correlated with the tectonic plate movement and crustal deformation in the study area, and consistent with that revealed by focal mechanism solutions from earthquakes. The results in the present study may provide in situ stress information for the design of planned dams and tunnels, and make a good complement to the World Stress Map.