RESUMO
The temperature factor is an important factor affecting the intercomponent forces while maintaining the physical stability of solid-liquid mixed fuels. Through self-designed experimental equipment, feedback was provided on the fuel stratification and density distribution uniformity with solid-liquid volume ratios of 1.25:1 and 1:1 under different temperature conditions. As the viscosity of the liquid increased with decreasing temperature, the ability of the fuel to overcome particle deposition was enhanced. Although none of the three fuel ratios with a solid-liquid volume ratio of 1.25:1 showed stratification, the differences in the liquid bridging forces of the components resulted in an increasingly uneven distribution of density with increasing surface tension of the liquid components. By analyzing the imaging results and measuring the liquid bridge force, it was found that the fuel with a nitromethane mass ratio of 40% had the lowest temperature effect on the solid-liquid contact area and the most uniform density distribution. Properly reducing the surface tension of liquid components could effectively resist the influence of the temperature on the liquid bridge force while maintaining the physical stability of the fuel.
RESUMO
The mechanism of transport of (14)C-fluoranthene by Rhodococcus sp. BAP-1, a Gram-positive bacterium isolated from crude oil-polluted soil, was examined. Our finding demonstrated that the mechanism for fluoranthene travel across the cell membrane in Rhodococcus sp. BAP-1 requires energy. Meanwhile, the transport of fluoranthene involves concurrent catabolism of (14)C, that leading to the generation of significant amount of (14)CO2. Combined with trans-membrane transport dynamic and response surface methodology, a significant influence of temperature, pH and salinity on cellular uptake rate was screened by Plackett-Burman design. Then, Box-Behnken design was employed to optimize and enhanced the trans-membrane transport process. The results predicted by Box-Behnken design indicated that the maximum cellular uptake rate of fluoranthene could be achieve to 0.308µmolmin(-1)mg(-1)·protein (observed) and 0.304µmolmin(-1)mg(-1)·protein (predicted) when the initial temperature, pH and salinity were set at 20°C, 9% and 1%, respectively.
