Applied Mechanics and Materials Vols. 71-78

Abstract: In the process of developing e-commerce system, enterprises are able to accurately understand and grasp the needs of the user enterprise that is the key to the successful implementation of e-commerce. Based on this, the article proposed a new method which was based on the process of developing consumer demand for e-business decision-making though a rough set theory. This new approach is built using rough set decision model to calculate the different needs of the impact on consumer satisfaction, come to an important degree of each demand and the demand reduction order. This method overcomes the traditional rough set method cumbersome bottlenecks, and helps operating; cases studies show that the proposed method is simple and effective.

Abstract: In order to reduce fluorine pollution, partial fluoride could be replaced by K₂O in mould flux. The effects of K₂O on melting temperature, viscosity, fluidity, surface tension, Al₂O₃ inclusion and adsorption of low fluoride content mould flux for high speed continuous casting were studied. The results showed that with the increase of K₂O content, melting temperature, viscosity and surface tension of mould flux decreased obviously, and fluidity and Al₂O₃ inclusion adsorption increased. When basicity was 0.81, 1.03 and 1.22, the suitable content of K₂O was 5%, 5% and 4% respectively, which could play an effective role. Partial fluoride could be replaced by K₂O in mould flux.

Abstract: In order to promote the hydrolysis and disintegration of waste sludge, the most logical approach is pretreatments to disrupt the microbial cells of sludge. After microwave pretreatments, the heavy metal which were toxicity to H₂ production were released from waste sludge, and the increase rate was 10.6 (Cu), 5.5(Cd), 3.6(Zn) and 1.6 (Ni) times after pretreatment. Carbonate hydroxylapatite (CHAP) had high efficiency in heavy metal removal. In this study, the effect of heavy metal removal on bio-hydrogen production from microwave pretreated sludge using CHAP was evaluated. 0.53 g/gVSS CHAP addition could enhance the bio-hydrogen yield by 53.6% compared with control, and the lag time was 9 h. Dosages of CHAP couldinfluence the hydrolysis, fermentation type and hydrogen yield of pretreated sludge.

Abstract: The analytical method for the determination of trace polycyclic aromatic hydrocarbons (PAHs) in environmental soil by ultrasonic assisted soxhlet extraction coupled with constant energy synchronous fluorescence spectrometry was described.The results indicated that were taken in Longyan City XinLuo District of soil containing 9 components: Benzo(k)fluorathene, Anthracene, Fluorathene, 1,12-benzoperylene, 2,3-benzanthracene, 1,2,5,6-dibenzo-anthracene, Fluorene, 2,3-Benzofluorene, Coronene and that the concentrations of PA Hs are in the range of 9.344~372.986 ng.g^-1. Industrial area around the PAHs were relatively higher in concentration in the soil, non-industrial area around the PAHs increased with the increase of human activity increased.

Abstract: Few studies have been done on temporal changes of heavy metal pollution of urban soils. Eight soil samples at the same sites were collected in Kaifeng City, China, in 1994 and 2006. Concentrations of Pb, Cd, As and Hg in the samples was measured. The pollution change of heavy metals from 1994 to 2006, and the relations between metal pollution and some human factors were discussed. The results show that soil pollution with metals in 2006 was higher than that in 1994 with economic growth. Soils in industrial district (ID) were more strongly polluted than in the following districts: (i) cultural and educational district (CED), (ii) mixed district of resident-commerce-administration (RCD), (iii) recreational district (RD), and (iv) suburban district (SD). Cd and Hg were the dominant pollutants. Economic growth, changes of land use and land-use authority can influence soil metal pollution significantly.

Abstract: The corrosion behaviors of ferritic/martensitic steel P92, austenitic stainless steel TP347HFG and HR3C have been investigated in supercritical water (SCW) at 550°C under 25MPa with 2ppm dissolved oxygen. After 600h exposue, all the samples formed a stable oxide layer, but of varying thickness and microstructure. A typical dual-layered oxide film on P92 and a single-layered structure on TP347HFG and HR3C were observed by SEM and EDS. Further XRD studies indicated the compositions of oxide layers weren’t independent to the type of the used steel. In comparison with ferritic/martensitic steel, austenitic steel showed a higher corrosion resistance.

Abstract: This study was performed to illustrate the effects of preoxidation by potassium permanganate on the fluorescence spectrum of Microcysis aeruginosa, a kind of blue-green algae. The results showed there were four dominate excitation/emission (Ex/Em) wavelength pairs, 230/334, 280/312, 280/334 and 620/642 nm/nm in the fluorescence spectra of algae and their derived organic matters (AOM). Coagulation resulted in desorption of the organic matter adsorbed in algae cells and produced two new fluorophores centered at 275/460 and 400/460 nm/nm. Potassium permanganate preoxidation could reduce the fluorescence intensity of algae and dissolved algal organic matters effectively and the descent rate increased with increasing potassium permanganate dosage.

Abstract: Hydrogen production from molasses wastewater was investigated in continuously-stirred tank reactor (CSTR). The CSTR was operated at an hydraulic retention time (HRT) of 6 hours and the temperature at 35°C. The highest gas production of 25.39 L/d using mixed culture fermentation, corresponding to a peak hydrogen production volume of 11.39 L/d were achieved in the CSTR reactor. While the variation of chemical oxygen demand (COD) ranged from 5500 to 8000 mg/L, the soluble end product system underwent a transition of fermentation type and the reactor gave fluctuating and increasing of ORP. These experimental results demonstrate that the shock-loading and micro-anaerobic circumstance are important factors for enhancing and stabilizing H₂ production.

Abstract: This study investigated the effects of initial pHs and temperatures to the hydrogen production ration and cell growth of Biohydrogenbacterium R3 sp.nov.. The initial pHs were set at 4.0, 4.5, 5.0, 5.5, 6.0, 6.5 and 6.7, respectively and the temperatures were increased from 25 °C to 45 °C in regular intervals of 5 °C at 10 g/L of the initial glucose concentration. The results indicated that pH value had a noticeable effect on the cell growth and hydrogen production. The dry cell weight and hydrogen production yield got the maximum of 0.6308 g/L and 34.2 mmol/L, respectively when the initial pH was 5.5. The final pH in the culture were always kept at 3.0~4.0. Temperature is also known to affect the maximum cell growth and specific hydrogen production ration (SHPR). And they got the maximum of 0.6682 g/L and 1.0145mol H₂/mol glucose, respectively when the temperature was 30 °C. It is obvious that hydrogen production and biomass will be inhibited gradually with increasing this pH and temperature or decreasing it.

Abstract: According to the fundamental theory of soil water dynamics, the mathematical model of 2-D unsaturated soils water movement with variable is established under the condition of furrow irrigation or underground channel seepage irrigation,and is calculated by the finite element numerical simulation method .The numerical simulation shows that the calculated results of numerical simulation is in good agreement with the measured date of experiment.