Applied Mechanics and Materials Vols. 295-298

Abstract: The speciation of potentially toxic heavy metal elements Arsenic in waste rocks of mining activities in Xinqiao Pyrite Mine was studied by conducting improved five step sequential extraction method. The arsenic mainly existed in silicate, secondly in deoxidize, and the exchangeable, oxidizable and carbonate modes content were low. When the waste rocks reacted with the acid mine drainage, the arsenic in the deoxidize and oxidizable modes might easily release from the waste rocks. So the arsenic had high environmental risk.

Abstract: This paper presents the airflow distribution and the dust production mechanisms due to the rotary dumping of powered materials in a hemi-closure space using theoretical method and numerical simulations, as well as the measurement results. The materials make parabolic movements and cause the splash of the dust by impacting with the static dust and walls of the storage. The dust volume relates to the height difference of the materials dumping and horizontal velocity of the dust. The further diffusion of dust is affected by several kinds of airflow with fan airflow which is the main factor. The calculative formula for the airflow volume is given, which can also be used in the similar ventilation and dust removal system directly.

Abstract: The study and selection of heavy metal hyperaccumulation and its planting methods and a rapid and efficient elimination of heavy metals in the contaminated environment are important research focuses to deal with the restoration and controlling of heavy metal contaminated environment. This experiment aims to explore the accumulation and accumulation characteristics of Cd on Hibiscus esulentus L in the simulation heavy metal contaminated environment achieved by pot cultivating techniques. To this end, different concentrations of heavy metal CdSO4 were used as treatment. The results indicated that with increase of the concentration of CdSO4, the accumulation of Cd in Hibiscus esulentus L was increased. When the treatment concentration of CdSO4 was at its highest (100mg/Kg), the accumulation of Cd on the above ground was 0.498mg/gDW, the highest, and that under the ground was 0.117mg/gDW. In view that the relationship of Hibiscus esulentus L of its above ground part(S) and its underground part (R) is S/R>1, experimental evidence shows that it has the basic characteristic of Cd hyperaccumulation.

Abstract: The effect of a freshwater bacterium Exiguobacterium sp.013 was examined on the cultures of four freshwater Microcystis which can cause cyanobacterial blooms. Four freshwater Microcystis cells and the bacterium were inoculated simultaneously, in modified BG-11 culture media, and cultured for 24 days continuously. The specific growth rate and cell densities were employed and determined in treated cultures and in controls.Additionally, dynamic changes of bacterium were investigated during the whole cultures. The results showed that the specific growth rate and maximal cell density of M. aeruginosa, M. flos-aquae and M. wesenbergii in treated cultures were significantly enhanced than that of control cultures, and daily cell densities of four Microcystis in the treated cultures were also significantly higher compared with that of control cultures. The added bacterial strain always kept dominance among the bacterial flora during the culture period. These findings implied that bacteria Exiguobacterium sp. might play a positive promoting role in forming Microcystis blooms under the eutrophication condition.

Abstract: First, this paper estimates all kinds of non-point source pollutant emissions in the source areas of Liao river, then calculates the pollutant quantity discharged into the river from rural living sources, planting pollution sources, livestock and poultry breeding pollution sources and aquaculture pollution sources in detail in the source areas. The results of the paper could provide a scientific basis for making a far-reaching significant watershed management scheme.

Abstract: Surface response optimization of adsorption process of neutral red dye wastewater by bamboo shoot hulls with the factors of pH value, amount of adsorbent, adsorption temperature, adsorption time and the response of adsorption rate were studied. The optimal parameters for adsorption process were of adsorbent concentration of 100 mg·L-1, adsorbent particle size of 60~80 mesh, pH 4.49, adsorbent amount of 3.65 g·L-1, adsorption time and temperature of 2.23 h and 39.70 °C, respectively. The maximal absorption rate got 98.37%. The adsorption follows the Langmuir and Freundlich isotherms, its dynamic behavior was consistent with the second-order reaction rate equations, the adsorption quantity was 179.3201 mg·g-1 at 30 °C. The apparent thermodynamic calculation of infrared spectroscopy showed that the adsorption process were of a spontaneous heat-emitting physical adsorption other than a simple chemical adsorption. Mechanical study showed that the functional groups were of hydroxyl and carbonyl groups on the pore and rough surfaces inside the hulls of bamboo shoots. Bamboo shoot hulls are good biological adsorption materials.

Abstract: A serial of numerical experiments were conducted with four representative sand and dust emission schemes using an integrated numerical simulation and forecast system of dust storms. The comparison between the simulation results and the observation data shows that the vertical dust flux and the dust concentration of the scheme developed by Marticorena and Bergametti is the biggest, while those of the scheme developed by Lu and Shao is the smallest. The simulation effect of the dust emission scheme developed by Shao is similar to the observation, so the dust model system of Shao is preferably used to predict the dust events in China.

Abstract: The emissions trading has significant environmental, economic and social benefits, and so far, China already has the foundation for implementation. Combied with the development of the current information technology and application level, this paper proposes a set of Emission Trading System and Functional Analysis of design ideas. The system starts from Platform Analysis, selects a reasonable and effective advanced technology solutions (.Net + Mysql + GPRS), owns a detail design of the data flow and emissions trading program. It also layouts a number of subsystems in function, which focus on emissions trading functions. Finally, it provides a better systematic implementation of emissions trading platform and strong support for the implementation of security.

Abstract: Phosphorus is the key restraining factor for algal growth and water eutrophication, which is a global problem of environmental pollution. Using a sequential phosphorus extraction method, the phosphorus forms in sediment and their distribution from different trophic area of Taihu Lake (China) and their temporal changes were studied. Results showed that, concentration of Fe-P in sediment was the highest and successively Al-P, which was much higher than that of Ca2-P, Ca10-P, Ca8-P and O-P. All the phosphorus forms were more abundant in sediment 16# of eutrophic lake area, higher than that of moderate eutrophic and the lower-grade trophic area, with the last as relatively the lowest. Phosphorus concentration in June and September was much higher than that of March. Phosphorus in sediment of Taihu Lake had great releasing potential to the overlying water.

Abstract: The research was the character of the urban sludge burning with coal by using the elemental anaylsis, component analysis, proximate analysis and thermogravimetric analysis. There is a big different elemental composition between the urban sludge and coal. For example, the carbon content (20.64%) in the sludge is only 31.3% of the coal. SiO₂ in sludge incineration ash contain up to 15%, the same as SiO₂ in Siliceous clinker. The sludge ash content (56.46%) is 2 times of in coal ash, an_{Subscript text}d the volatile of sludge (34.6377%)is higher than the volatile of coal (25.089%), the sludge incineration can be divided into three stages: moisture volatilizing stage (30°C to 160°C), devolatilization combustion stage (160°C to 500°C) and fixed carbon and residual combustibles burning stage (510°C to 950°C). The heating rate increased, the volatiles volatilized advance about 50°C. Therefore, the sludge is a high value fuel, which can be used in the burning with coal or building materials.