Applied Mechanics and Materials Vols. 71-78

Abstract: Nano-ZnO, nano-TiO₂ and their mixed catalyst respectively degrade methyl orange solution with concentration 10mg/L in sunlight. When the dosing quantity is 1g/L during 8h degradation, the degradation effect is better and the degradation rates of three catalysts can all reach more than 93% with prolonging of degradation time, and the degradation effect of mixed catalyst is best and its degradation rate reaches more than 99%. Moreover the effect of TiO₂ content in the mixed catalyst on catalytic degradation isn’t distinct.

Abstract: The microcosm tests were done to estimated the HRT (Hydraulic Retention Time) and removal efficiency of reflowing treatment of the landfill leachate collected from Dalian Maoyingzi Municipal Solid Waste Landfill, which contained high levels of COD (Chemical Oxygen Demand, 38400 mg/L) and SS (Suspended Solids, 650 mg/L) by the reed constructed wetland located in the south area of Dalian Jiaotong University. The results showed that: (1) The HRT in nature soil cuboids were significant shorter than those in sieved soil cuboids (P<0.01); (2) The removal efficiency among the output water with the trend as follows: Preferential flow (53.9%)<Percolating water (59.2%)<Reflowing water (63.3%); (3) The COD and SS were decreased from 38400 and 650 mg/L to 14080 and 213 mg/L by the way of reflowing with the HSL (Hydraulic Surface Loading) of 0.16 m³/(m²·d) by reflowing (Removal efficiency: COD: 63.3%; SS: 67.3%).

Abstract: In this study, results of degradation of fuchsine solution are presented by using direct current (DC) atmospheric pressure air discharge plasma. The maximum absorption at 542 nm was reduced from 10.376 to 0.062 after 15 minutes plasma treatment, corresponding to the reduction of fuchsine solution concentration from 100 mg/L down to 1.419 mg/L, which indicated that the degradation efficiency is as high as 98.51%. A notable decreasing of degradation efficiency caused from the adding of sodium carbonate suggests that free radical species is a main factor accounting for the fuchsine solution degradation. The experimental results also reveal that the solution conductivity was increased with treatment time, while the solution PH was decreased, which may show that large amount of inorganic species, such as NO₃^- and H⁺, were produced. Within the current paper, it can be concluded that the DC atmospheric pressure air discharge plasma is capable of an efficient technology for the degradation of dye wastewater.

Abstract: Substance flow analysis (SFA) is a kind of quantitative analysis on the metabolism of industrial process. This paper analyzed the metabolism route of copper, the main contaminant of PCB industry from the aspect of enterprise, in the manufacturing of PCBs, calculated the flux of copper between all the nodes, and studied the efficiency of copper in order to improve it. As shown from this paper, the relatively low efficiency of copper usage resulted in the copper contamination of PCB industry, which was often emitted into the environment as etching waste liquid or solid waste. Therefore, this paper proposed that we should regard the improvement of the efficiency of copper usage as key to cut off copper contamination in PCB industry, namely the focus on cleaner production with recycling of copper wastes.

Abstract: A total of 28 atmospheric particulate matter samples were collected at Henan Polytechnic University in the southeast of Jiaozuo city during October to December 2010. The daily concentrations of PM₁₀ vary from 190.76 to 670.14 μg/m³, with the average concentration of 359.36 μg/m³. The concentrations of Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, Fe, Cu, Zn, Mn and Pb in PM₁₀ are determined by Energy Dispersive X-Ray Fluorescence (EDXRF). The result shows that the fifteen elements quality accounts for 17.3%~36.7% of total mass. The X-ray diffraction (XRD) results show that six minerals are identified in the atmospheric particles. They are quartz, gypsum, kaolinite, sal-ammoniac, calcite, and albite, which account for 29%, 29%, 18%, 17%, 4% and 3%, respectively. The principle component analysis (PCA) model is used for source apportionment of PM₁₀. The research results show that there are four sources: architecture/smelting action, coal combustion/traffic action, soil dust and particular industrial action.

Abstract: There are many hard degraded materials in the papermaking wastewater such as lignin and cellulose[1]. Because of its deeper color and high concentration of small colloidal substances, usually , it needs flocculation process as pretreatment or advanced treatment[2]. In this paper, it used the FeSO₄ as flocculant to find the best pH of the reaction and the optimum dosage through detecting the COD, turbidity and chroma of the raw papermaking water and the terminal drainage.

Abstract: This study introduces a new method for assessing the outdoor ventilation environment in Taiwan, with a view to reducing the heat island phenomenon. The ventilation environment is important in cooling the outdoor environment, but its evaluation is very difficult and complex. Therefore, this study develops a simple method for assessing the outdoor ventilation environment, it is used in computational fluid dynamics (CFD) simulation software, only to generate numerical models using empirical building types include rectangular shape and courtyard building, then calculate their wind shadow areas (WSa). Then, many factors, such as the site plan, the size of building and local wind data are used to draw these areas to the scope of WSa. The results of the simple assessment method are verified by performing CFD simulations to corroborate the correlation between simplified assessment method and CFD simulation result, an R² value of 0.87 is obtained. The method is helpful in improving design decisions in the planning and design stage of site plan.

Abstract: This research investigated the distributive characteristics of soil microorganisms at dry lake wetland on semiarid grassland. Four plots, typical steppe (DT), lake side (HB), lake bed (HD), and lake center (HX), were selected from Huitengxile located in semiarid grassland to conducted this investigation. The results showed that the number of aerobic bacteria at DT is 1.07 times that at HB, 1.14 times that at HX, and 1.45 times that at HD. The number of fungi at DT is 3.81 times that at HD, 10.65 times that at HB, and 25.75 times that at HX. There is significant difference between HX, HB and the other two plots (p<0.05). Also, there is significant difference between HD and DT. The number of Spore-forming bacteria at DT is 1.65 times that at HD, 2.15 times that at HB, and 6.35 times that at HX. There is significant difference between HD, HB and the other two plots, as well. The number of actinomycetes at HB is highest which is 2.12 times that at HD, 2.27 times that at DT, and 3.43 times that at HX. Moreover, there is a distinct feature of transverse distribution for soil microorganisms communities at dry lake wetland on semiarid grassland. Excluding actinomycetes, the number of soil microorganisms at dry lake wetland were both lower than that at typical steppe. There is a significant correlation between the total amount of soil microorganisms and microbial biomass C at dry lake wetland. These results can be used as the theoretical foundation for the restoration of degraded lake wetland, and the exploitation and utilization of wetland microbial resources.

Abstract: The growth condition of Chlorella spp was optimized to increase its biomass. Under the aseptic culture condition, major nutritional factors for Chlorella spp growth, such as Na₂CO₃, NaNO₃, KH₂PO₄ and MgSO₄ were optimized. Trace elements and pH value had a prominent influence on the growth of Chlorella. Optimized culture medium program was as follows: Na₂CO₃ 0.02g/L, NaNO₃ 2.0g/L, KH₂PO4 0.02g/L, MgSO4 0.1g/L and ambient conditions of pH value 6.0. The research could lay foundation for t the cultivation of Chlorella spp. on a large scale.

Abstract: In this study, seasonal biogenic volatile organic compound (BVOC) emission rates and emission patterns of Ginkgo biloba linn are estimated. The released volatiles were collected from branches onto cartridges filled with Tenax TA, and quantified by thermal desorption gas chromatography mass spectrometry (GC-MS). The result showed that the main BVOCs emitted from Ginkgo biloba linn were alkanes, aldehydes, alkenes, aromatic compounds, esters, terpenes and ketones. The total BVOC emission rate increased from May, and reached its maximum 27.96 μg C g^-1dw h^-1 in July, then decreased quickly. The emissions of α-pinene, isoprene, cyclohexane, methyl-cyclohexane and 2-methyl-hexane were significantly correlated to both temperature (p<0.05) and light (p<0.05).