Applied Mechanics and Materials Vols. 295-298

Abstract: Hydrolytic enzymes, which are very key enzymes in hydrolytic step of anaerobic digestion, have an important effect on substrate hydrolysis and biogas production. To research those effect, this paper have investigated the relationship between lipase activity and biogas rate with organic fraction of municipal solid waste (OFMSW) as substrate, at the mesophilic temperature and batch fermentation. The results showed that in the process of AD, the curve of lipase activity was similar as that of biogas rate. With the increase and drop of enzyme activity, biogas rate increased and dropped. When biogas rate was at its peak period, enzyme activity of lipase was at its peak period, too.

Abstract: Yttrium (Y) and Europium (Eu) were recovered from waste phosphors of TV screens via several processes, including roasting waste phosphors with ammonia chloride, dissolving yttrium chloride and europium chloride with water from roasted waste phosphors, purification with sodium sulfide, precipitating in the presence oxalic acid and calcining at high temperature. The optimal conditions for roasting was investigated, and it was found that when 1 g sample reacts with 8 g ammonia chloride, the recovery rate of Y and Eu can be 92.12% and 90.38% after 30min reaction at 90°C, respectively. Moreover, the optimal pH value for recovering Y and Eu was also investigated. It was found that at pH=1, the stoichiometric ratio of B/A (A: S^2-, B: Zn²⁺, etc) is 1:1, the stoichiometric ratio of B/A (A: Y³⁺, B: C₂O₄^2-, etc) is 2:1, the content of Y and Eu can be reached 98.10% and 96.30%, respectively. And yttrium europium oxide was finally synthesized, which produce the red light when the excitation wavelength was 242 nm.

Abstract: This article summarizes the concept and classification of plasma. The application of plasma technology for the treatment of waste gas, waste water and solid waste are also introduced, and future developments of plasma technology in the field of environmental protection are discussed.

Abstract: Four industrial wastes: iron scraps, ceramsite, fly ash and steel slag were studied as reactive media for COD removal from the Fenhe River. Leaching tests demonstrated that iron scraps and ceramsite were relatively stable compared to steel slag and fly ash. Ca²⁺ was the main leaching ion. Batch experiment results showed that iron scraps and steel slag had better COD removal efficiency than ceramsite and fly ash. It was also found that the initial pH was important for COD removal and the COD removal efficiency of iron scraps was linearly correlated with the initial pH (R²=0.982). Compared to batch experiments, COD removal was much higher in column tests, which were about 70%, 54%, 46% for iron scraps, steel slag and ceramsite respectively.

Abstract: To research influence of water level changes on vegetations restoration in water-level-fluctuating zone of the Three Gorges Reservoir, Cynodon dactylon in Changshou area was respectively investigated in 2008 and 2009. The results show that germination rate in 2009 is 45.3% lower than that in 2008. Total rhizome length and total node number of rhizomes in 2009 significantly increase by 303.5% and 411.1%, respectively. However, stem length, node number, leaf width and leaf number of ramets decrease by 60.1%, 55.1%, 28.6% and 33.8%, respectively. Meanwhile, total buds number, germinated buds number and buds number to rhizome length ratio in 2009 increase by 500.7%, 228.5% and 50.9%, respectively. Compared with 2008, fresh mass of ramats, rhizomes and roots reduce respectively 65.6%, 23.4% and 70.0%, and their dry mass reduce respectively 65.9%, 18.8% and 64.5%. Therefore, water level changes accelerate rhizomes extension and the formation of buds and ramets, and inhibite ramets growth.

Abstract: At present, water environment pollution and unsafe drinking water is a serious problem,only depending on technology difficult to solve,need for finding ways from cultural perspective. Chinese water culture construction can be roughly divided into four stages, Chinese water culture connotation is analysed, the basic framework system of water culture is puts forward. The basic characteristics of water culture is the cultural relations between human and water based on the water cycle as foundation,the water as the carrier,the water engineering as object. The main body of water culture includes water conservancy culture and water supply and drainage culture,the current water culture construction ignores water supply and drainage culture. Establish the two-stage water culture education system includes the general public and water professionals based on the core of drinking water security concept,which plays a key role in improving the water environment and unsafe drinking water, especially in rural areas.

Abstract: Current talents cultivating can not meet the modern requirements of water supply and drainage project. CCDIO is defined as the center of students' career development with engineering or product life cycle as a carrier, meaning career development,conceive, design, implement, operate. Teaching system based on CCDIO consists of six systems including talents cultivating scheme, curriculum system, practice and training system, teaching quality assurance system, teacher training system, student career development system.Curriculum system includes engineering foundation and introduction, engineering conceive and design, engineering implement, engineering operate. CCDIO engineering education contributes to cultivating qualified modern water supply and drainage engineer, providing with talents for solving the water crisis.

Abstract: The 3-D finite element model of a concrete gravity dam’s spillway was established in this paper, and the elastic-plastic theory was applied, then the deformation and stress state of the dam under various working conditions were analyzed, it was prooved that the deformation and stress state of the dam were in normal condition. After solving the force of the dam foundation surface and taking full account of the complex geological conditions, the dam’s sliding stability was analyzed by capacity limit state design formula. The calculation results showed that, the stability parameter of the dam along foundation surface was bigger than 1.0, the dam’s sliding stability met the requirement.

Abstract: This paper mainly introduces the important significance on the optimization of water supply pipe network . And in terms of the present situation of and problems existing in china’s urban water suppling,puts forward a series of concrete measures for the network optimization .

Abstract: The paper summarized current situation and treatment technology of the reclaimed water reuse at domestic and international, and analyzed benefits and development obstacles of the reclaimed water reuse.