Applied Mechanics and Materials Vols. 209-211

Abstract: To evaluate the toxic effects of environmental contaminant PFOS on green algae, Scenedesmus obliqnus was cultured in media containing serially diluted PFOS for evaluation of proliferation capacity and some physiological indexes. Within 96h, PFOS doses ≥50 mg/L all inhibited the proliferation speed of Scenedesmus obliqnus(p<0.05). The 96h EC50 value of PFOS was determined to be 126 mg/L. In a chronic experiment with 8 days of PFOS treatment, chlorophyll a content, which was inhibited by even the lowest dose, showed to be the most sensitive index to PFOS contamination. PFOS doses ≥100mg/L all resulted in decreasing of antioxidant enzyme activity and increasing of MDA content in Scenedesmus obliqnus(P<0.05).

Abstract: This paper introduced a better solution to accelerating the production of biodiesel from waste cooking oil by using suitable acidic and alkaline catalysts in a two-stage catalytic reaction. Next, a co-solvent named tetrahydrofuran (THF), which significantly increased mixing level of the reactants in the mixture of vegetable oil and methanol, was added to form a single phase system. The whole system was then put into a microwave oven to support heat for the transesterification of biodiesel to shorten the reaction time. Reaction conditions of the first stage were methanol to oil molar ratio of 9:1, catalyst amount 1wt%, reaction temperature 60 oC and reaction time 7.5 minutes. In the second stage, for the transesterification, reaction conditions were methanol to oil molar ratio 12:1, catalyst loadings 1 wt%, reaction temperature 60 oC and reaction time 1.5 minutes. Finally, the conversion rate of biodiesel after the nine-minute reaction time was 97.38% which was higher than the EU EN14214 standard value of 96.5%.

Abstract: The internal contamination has played a significant role in eutrophication after external contamination was effectively controlled. Zeolite capping is selected to explore the release and transformation mechanisms of moderately labile organic phosphorus (MLOP) control. The result showed that the release of MLOP under weak acidic environment and weak alkaline environment are more readily achieved compared with that under neutral environments. Low temperature and light both promotes the release of MLOP. Particle sizes has no apparent effect. The release of MLOP is prohibitted by high dissolved oxygen (DO) concentration. The phosphorus released from sediments is readily absorbed by zeolite in the weak acidic or weak alkaline water body, high temperature and DO concentration.

Abstract: The environment capacity is not only importance to maintain the balance of nature, but also influence the socio-economic development well being in grassland regions. Take the case of Damao County in Baotou City Inner Mongolia located on the arid and semi-arid area in northern China and a fragile ecosystem, indicators system of grassland environment capacity are constructed and then analyzed the grassland environment capacity quantitatively. The result shows that the grassland environment capacity is an allowable state in 1992 and 2000, but it is an overloading state in 2009, so natural resources on the grassland has not support the demand of regional economic and social development based mainly on animal husbandry in Damao County, applying some effective measures to protect grassland and maintain ecosystem stability.

Abstract: Based on the mesophilic two-phase anaerobic reactor for maize ethanol wastewater treatment, the start-up, cultivation and the morphology of mature granular sludge in improved methanogenic UASB were studied. The reactor was initiated at a low loading rate. By means of increasing volume loading rate gradually and regulating internal circulation, the improved methanogenic UASB was operated under an optimal condition. After more than two months of operation, the size for the 63% of total granular sludge was more than 1.3mm, the biogas production rate and COD removal rate achieved 539L/d and 90%, respectively. Start-up of improved methanogenic UASB was accomplished successfully. Improved UASB, served as methanogenic phase of two phase anaerobic process, can adjust pH value of influent automatically. The manual regulation of pH value during start-up could be stopped when the granular sludge in improved methanogenic UASB went into maturity stage. The microfloras of mature methanogenic granular sludge are mainly brevibacterium and filamentous bacteria. Methanothrix soehngenii is the dominant consortium after the long-term operation under low-strength.

Abstract: After initial screening on enrichment media, with subsequent sequential isolation on minimal media containing the cypermethrin as sole C source, three degrading strains were isolated from cypermethrin polluted soil. Gas chromatography was used to measure the rates of disappearance of the cypermethrin, the strain L0 was identified as Bacillius sp. preliminarily. The optimum growth conditions for the aerobic degradation of cypermethrin by L0 were 26°C, pH 7. The degrade rate of cypermethrin by L0 is more than 87.54% above conditions after cultivated for 72 hours. Strain L0 is a high effect degradation bacterium should be used for a bioremediation process of the contaminated soils by insecticides and decrease the environmental pollution.

Abstract: The eddy covariance is a micrometeorological technique to observe and investigate ecosystem flux nondestructively, as well as the main method the eddy covariance may help to research carbon dioxide exchange between global vegetations and the atmosphere. Carbon dioxide flux has been monitored on Xilamuren grassland of Wulanchabu city by Open Path Eddy Covariance System (OP-2). Carbon dioxide flux shows that carbon absorption is greater than its release, which has an evident carbon sink functions and obvious seasonal variety on the basis of experimental data from June 2009 to July 2011.

Abstract: Two ecological indicators, exergy (Ex) and structural exergy (Exst), and two ecological indexes, biodiversity and trophic state are calculated using the parameters of water quality and plankton investigated in five different ponds in Shandong province in China. The exergy and structural exergy are applied to evaluate the health state of ecosystems of the five ponds, whereas the biodiversity and trophic state are employed to make eutrophication assessment of the ponds. Via analyzing the relationships among the ecological indicators, the ecological indexes and the biomass of macrophytes, it is revealed that exergy, structural exergy and biodiversity is positive correlated to the biomass of macrophytes and that the trophic state decreases with the biomass of macrophytes. This result demonstrates that the ecosystems with more macrophytes can be regarded to hold better health state.

Abstract: Bacillus fusiformis CGMCC1347, screened from soil, was immobilized successfully to biotransform isoeugenol to vanillin. The optimal immobilization conditions were 2.5% sodium alginate, 10% cell density and Ca2+ 0.1 mol l-1. The optimal reaction conditions in a 2 L CSTR reactor with immobilized Bacillus fusiformis CGMCC1347 cells were isoeugenol 600 mL, immobilized cells 400 g, pH 3.5 dH2O 400 mL, 37 oC, 200 r min-1 shaking speed and 0.8 vvm air capacity. The average vanillin concentration reached 39.26 g l-1 after 6 times reuse of immobilized cells in 2 L CSTR.

Abstract: In recent years, as a result of personal factors and natural factors of climate, soil, vegetation and so on, grasslands eco-environment worsens continuously, desertification is intensifying and soil and water loss is very severe, which is directly threatening to the national ecological security and sustainable development of national economy. On the basis of predecessors' achievements and our previous work, selecting the WuLanChaBu desert grasslands of the inner Mongolia as main study areas, where soil and water loss is severe and wind erosion and water erosion interact, we using the research approach combining field survey，remote sensing interpreter with field dynamic observations to analyze and study the characteristic of wind-water alternate erosion of the desert grasslands.