Applied Mechanics and Materials Vols. 295-298

Abstract: The reverse atom transfer radical polymerization (RATRP) of N-vinylpyrrolidone (NVP) using azobisisobutyronitrile (AIBN)/FeCl3/triphenylphosphine(PPh3) as the initiating system, was successfully carried out in bulk at 80°C. Plots of In ([M]0/[M]) vs time and molecular weight evolution vs monomer conversion presented a linear dependence and the polymerization was proved to accord with the first-order kinetics. After 10 hours’ reaction, the monomer conversion was up to 84%. Gel permeation chromatography (GPC) was used in testing the molecular weight of polymer and molecular weight distribution, the results showed that polymer molecular weight distribution was as low as 1.018 (Mn=3288 g/mol). Moreover, the resultant polymer was characterized by 1H-NMR, 13C-NMR spectroscopy and Pyrolysis GC-MS, and the results showed that the polymerization mechanism is consistent with RATRP.

Abstract: This paper discusses the development of China’s port chemical industry and analyzes its advantages and disadvantages as well as the outside opportunities and threats, by means of SWOT analysis. The SWOT analysis of port chemical industry can help us make clear the subjective and objective conditions, better bring our strengths into play, avoid our demerits, seize the opportunities and respond to the challenges accordingly.

Abstract: Batch experiments were conducted to measure the sorption capacities of estrone (E1) to aerobic activated sludge. The effect of temperature on E1 sorption was investigated at the temperatures of 5-35oC. The results showed that E1 sorption equilibrium was reached at 15min. E1 sorption on the sludge fitted both Freundlich and linear sorption isotherm models. Distribution coefficients (Kd) of E1 to aerobic inactivated sludge was 546.5 L∙kg-1 at 25oC. The effect of temperature on sorption indicated that lower temperature benefited the sorption. The distribution coefficients (Kd) and sorption rate both decreased with the increased temperature. Kd of E1 to aerobic inactivated sludge was decreased by about 44%; the sorption rate was decreased by about 13% when temperature increased from 5 to 35oC. The specific sorption coefficient KOM or KOC was also used to describe the sorption capacity, which also decreased with increased temperature. Sorption thermodynamics indicated that the sorption process was exothermic and spontaneous.

Abstract: Internationally validated methods (ISO standards) for the determination of toxic effects were used in this study to evaluate the toxicity of metals [i.e. Hg, Cu, Zn, Pb and Cd] to a kind of marine algae, namely Chlorella autotrophica. In the test, the no observable effect concentration (NOEC) and the effective concentration for 50% of test algae (EC50) were obtained after 96-h of incubation at 25±1°C, by comparing the growth of the Chlorella autotrophica in the test samples and in the control. Among the 5 metal ions, mercury (Hg) was found to be the most toxic metal in the test (EC50=1.04 mmol/L), while cadmium (Cd) was the least toxic (EC50=151.37 mmol/L). The results from the Chi-square test of each dose-response equations showed that 96h-EC50s calculated were all precise and credible. According to both NOEC and 96h-EC50, the toxic sequence of these metals from high to low on the inhibition of Chlorella autotrophica’s growth was Hg2+, Cu2+, Zn2+, Pb2+ and Cd2+.

Abstract: Most Oilfield of China has been a stage of Oil recovery with high water, microbial residual oil gasification technology as the oilfield's reserves technology has a good application prospect, especially the use of microorganisms for gasification of residual oil. The study has far-reaching significance, and it mainly turns the difficult mining oil reservoir into natural gas (mainly methane) through microbial degradation. It is the most effective, economical and environment-friendly way to enhance oil recovery efficiency and to extend the reservoir life. This paper summarized the relevant principles of oil microbial degradation and gasification, microbial enhanced oil recovery and Residual oil gasification at home and abroad, and come up with a few new research ideas.

Abstract: Soil washing is a possible remediation technique for contaminant extracting from the soil. Thiacalix[4]arenetetrasulfonate has become an alternative to metal extractants due to its high selectivity and high stability. Batch soil-washing experiments were conducted to investigate the effect of pH on extraction efficiency of Cd from soil by the thiacalix[4]arenete-trasulfonate solution. Results showed that more than 82 percent of cadmium was extracted by the thiacalix[4]arenetetra- sulfonate solution from the artificially contaminated soil with the concentration of 562 mg/kg cadmium at the initial pH value of 11. Thiacalix[4]arenetetrasulfonate could be an attractive alternative in washing remediation of soil contaminated by Cd.

Abstract: Twelve strains belonging to the genus Cordyceps were investigated for their ability to degrade organochlorine pesticide dieldrin. Based on the screening results, we further investigated Cordyceps militaris KS-92 and Cordyceps brongniartii ATCC66779 to determine their degradation capacity and metabolic products towards dieldrin. C. militaris KS-92 and C. brongniartii ATCC66779 removed about 45% and 36% of dieldrin in PDB medium, respectively, after 28 days of incubation. A hydrolysis product, 6,7-dihydroxydihydroaldrin, was detected as a initial metabolite of dieldrin in both fungal cultures using GC/MS analysis. C. militaris KS-92 particularly can degrade dieldrin to dihydrochlordenedicarboxylic acid through oxidation of 6,7-dihydroxydihydroaldrin or directly oxidation of dieldrin. The results suggested that dieldrin was metabolized to hydrophilic/low-toxicity products by selected fungi.

Abstract: The repellent activitie of Cinnamomum japonicum oil against Aedes albopictus were investigated. The main volatile chemical components of the oil were qualitatively studied. The main results are given as follows. Cinnamomum japonicum oil providing absolute protection against Ae. albopictus in laboratory and field for 2.33 ± 0.63 h, 3.85 ± 0.21 h at concentration of 1.5 mg/cm², respectively. A total of 28 compounds were identified. The main components of the essential oil were borneoll (28.30%), 1,8-cCineole (20.98%), (-)-bBornyl acetate (6.65%), linalool (5.94%), (-)-.alpha.-terpinol (5.87%), caryophyllene oxlde (5.11%). The results indicates that Cinnamomum japonicum oil has a great potential to be developed into a ecofriendly mosquito repellent.

Abstract: Quorum sensing(QS) is a mechanism of microbes to coordinate their activities, which allows them to function as multi-cellular systems. Recently, many researches have proved that the engineered QS system have a wide range of applications such as bioremediation of oil and heavy metal contaminated soils, and prevention of biofouling. Here we review the function of QS signals produced by bacteria, and the principle of enhancing degradative capacities of microbe. Specifically, we describe how QS system regulate the formation and dispersion of biofilms, which are reversible process that biofilms may be generated and removed as desired. The development of strategies to disrupt and manipulate QS are also implicated. Cells can be engineered to secrete QS signals to affect the behavior of neighboring cells in a consortium via engineered cellular communication. The complete genetic basis of QS may be used to control these communities of associated cells for bioremediation applications.