The aim of this article is the study of the potential relationships between PAHs contamination, physicochemical parameters, and microbial activity in industrial soils. The research was based on two series of measurements. The first was conducted in June 2013 and the second in November 2013. Samples used in study were collected from the area of fuel handling and a loading station, located in the Silesia region of Poland. All collected samples were characterized by the following analytical procedures: PAHs content analysis, the basic physical and chemical parameters determinations (pH, CEC, humic acids content, TC, TN, TP) and microbial activity analysis. The obtained results were also subjected to statistical analysis, based on the Pearson's correlation coefficient calculations.
Results collected during described above procedure show that: the PAHs content was highly positively correlated with C and N contents (p < 0.001) and moderately correlated with humic acids and P contents (p < 0.01). This phenomenon confirms the thesis that the increase of soil organic matter content promotes accumulation of hydrophobic organic compounds such as PAHs. Microbiological analysis shows that bacteria from the mesophilic group are most resistant to PAHs contamination. This information indicates that the organisms belonging to this group should be considered as potentially useful in the soil bioremediation processes. 相似文献
The aim of this research was to observe the relationship between zeta potential, morphology, surface area, porosity, chemical composition, and ecotoxicity of nanocomposite powders such as Au/TiO2, Ag2O/TiO2, PdO/TiO2, Ag/TiO2/SiO2, Ag/N(C)TiO2, and SiO2/TiO2 from which Ag2O/TiO2, Ag/N(C)/TiO2, and Ag/TiO2/SiO2 were exhibiting good antimicrobial properties. It was observed, that nanomaterials characterized by similar morphology and zeta potential revealed the similar toxic behavior. The samples of higher agglomeration and higher zeta potential, especially Ag/TiO2/SiO2 xerogel and TiO2/SiO2 aerogel were generally less ecotoxic to water organisms and plants. They were also not genotoxic in concentrations up to 500 and 250 mg/L, respectively. 相似文献
In this paper, the bang-bang principle for a control system described by a system of non-linear (in control) non-autonomous partial differential equations of hyperbolic type (the so-called Goursat-Darboux problem) is proved. As a particular case the bang-bang principle for a linear system is obtained. The method used for the proof is based on some properties of the Aumann integral. 相似文献
In this study, the efficiency of wire electrical discharge machining of hard-to-machine materials was investigated experimentally. Uncoated brass wire, 0.25 mm diameter, zinc oxide coated brass wire and brass CuZn20 coated brass CuZn50 wire were utilized in the conducted research. The following variables were chosen as important WEDM parameters: discharge time ton, average working voltage U. The following properties of machined materials, such as: melting point Tt, electrical conductivity σ, thermal conductivity K, thermal expansion coefficient k, density ρ, heat capacity cp, were selected to develop the semi-empirical model of volumetric efficiency of WEDM. The variation of the WEDM efficiency in cutting different materials and applying different wire electrodes and different process parameters was modelled semi-empirically by employing dimensional analysis. 相似文献
We show that breadth-first traversal exploits the difference between the static delimited-control operator shift (alias S) and the dynamic delimited-control operator control (alias F). For the last 15 years, this difference has been repeatedly mentioned in the literature but it has only been illustrated with one-line toy examples. Breadth-first traversal fills this vacuum. 相似文献
In this paper we study the problem of ergodic impulsive control of Feller processes with costly information. We prove continuity of the value functions for optimal stopping and impulsive control with long run average cost. We characterize the value functions as generalized solutions of respective quasi-variational inequalities and describe optimal policies. We study also an equation associated to impulsive control with long run average cost. 相似文献