Applied Mechanics and Materials Vol. 692

Abstract: Water quality criteria (WQC) is based on the results of scientific experiments and inferences, which prescribe a limit threshold value to pollutants and other harmful factors in water. The system of water quality criteria study is basically a blank circumstance. It’s urgent to establish water quality criteria to adapt with the characters of China water environment to supply theoretic bases for revising water quality standards and managing environment. In this paper, an overview of the water quality criteria, as well as domestic and foreign research progress in theoretical methodology are systematically discussed, furthermore, considering current status of water quality criteria, comprehensive research were pointed out to be done in the future.

Abstract: Using plants Ophiopogon japonicus, with river sand and soil matrix to construct artificial wetland system, analyzes the effect of the purification of wastewater containing lead, and to study the influences of different flow on the purification efficiency. Experimental results show that the Ophiopogon japonicus artificial wetland to lead the lead in wastewater purification effect is good, with 2 L/d of wastewater flow trendy, Ophiopogon japonicus removal rate as high as 95.8%, of artificial wetland to lead bubbled into 16 L/d for wastewater discharge, removal rate can reach 85.3%.

Abstract: Abstract. The seed bank response of five pioneer plants, including Cynodon dactylon, Setaria viridis, Amorpha fruticosa, Alternanthera Philoxeroides and Xanthium sibiricum, to flooding were tested through simulating the flooding experiments. The flooding treatments included 30d, 60d, 90d and the control. All of the treated seeds were germinated under an appropriate germinate condition. The results showed that seed germination rate and germination index of Amorpha fruticosa and Xanthium sibiricum increased with the increasing flooding time meanwhile that of Setaria viridis and Alternanthera Philoxeroides decreased, and Cynodon dactylon germination decreased firstly and then increased with the increasing flooding time. The results suggested that flooding influenced significantly seed germination, and implicated that Amorpha fruticosa, Cynodon dactylon and Amorpha fruticosa were appropriate species for the construction of artificial seed bank to restore riverbank vegetation in the Three Gorges reservoir area.

Abstract: Response of soil respiration in temperate wetlands in northeast China was studied from June 2009 to September 2011. Li-Cor 6400 infrared gas analyzer connected with a chamber was used to quantify the soil respiration. Results showed that soil respiration displayed a distinct seasonal pattern, with higher values observed in midsummer and lower values in spring and autumn. Furthermore, soil respiration exhibited a significant inter-annual variation. In addition, soil respiration presented significant positive exponential relationships with soil temperature. Whereas, significant exponential decay relationships between soil respiration rate and soil water content was found. In this ecosystem, soil temperature, soil water content and plant phenology together control soil respiration.

Abstract: The comprehensive utilization of solid emissions from power plants has arose much attention in recent years. This paper first studied the present situation of the thermal power enterprise solid emissions market in China. Then by taking China Datang Tongzhou Technology Company as an example, its strengths, weaknesses, opportunities and threats were analyzed. Finally, based on the SWOT analysis, this paper put forward the effective methods to enhance the comprehensive utilization of solid wastes as well as the future development strategy of the company.

Abstract: Deep sea discharge engineering is a main sewage treatment means nearshore district, which has a characteristic of lower construction and operation cost. For guiding the engineering design, the preliminary site selection work need be implemented firstly. In this paper, based on the relative standard and domain planning, the preliminary site of sewage treatment by deep sea discharge is selected in the certain engineering marine of Fujian Province. A follow-up study is pointed out in the paper. The simulation of jet model and the diffusion of pollutant is the key tool for the detailed design of deep sea discharge engineering.

Abstract: This research established a density separation system by using sorting media such as calcium chloride solution (CaCl₂), sodium chloride solution (NaCl) and ethyl alcohol solution (C₂H₅OH) to study the density separation experiment involving nine different waste plastics. The results showed that PVC(or POM or PET), PC, PA6, PS(or ABS), HDPE and PP could be progressively separated from their mixtures by CaCl₂(1.3005g/mL), NaCl (1.1604g/mL), NaCl (1.0861g/mL), tap water (0.9969g/mL) and C₂H₅OH(0.9039g/mL) with a 100% of sorting rate, respectively.

Abstract: Danjiangkou Reservoir and its upstream tributaries as water resource area is of strategic importance for the Mid-route of South-to-North Water Transfer Project. Ecological and water security are the key measures for sustainable water diversion. Green water management as a new technology to achieve water conservation and water purification has a broad application prospects. In this research, green water management such as bench terraces, contour tillage, mulching and stone line was studied in the Upper Du watershed. ArcSWAT model was used to assess effect of green water management on river base flow. The results show that four green water management measures activated the regulating action of “soil water reservoir”. Base flow in export section of Upper Du river basin is increased under different four green water management measures, and especially the base flow increased more obvious in non-flood season. That is helpful to improve the ecological security degree in water resources area.

Abstract: This paper investigates the trends in precipitation time series of 10 stations for the time period of 51 years (1961-2011) in the Munda catchment, Pakistan. The Mann-Kendall (MK) and Spearman’s rho (SR) tests were employed for detection of the trend on the seasonal and annual basis at 5% significance level. For the removal of the serial correlation Trend Free Pre-Whitening approach was applied. The results show, a mixture of positive (increasing) and negative (decreasing) trends. A shift in precipitation time series is observed on seasonal scale from summer to autumn season. The Charbagh station exhibits the most number of significant cases on the seasonal basis while, no significant trends are found at Thalozom, Kalam and Dir stations. On the annual basis, only Charbagh station shows a significant positive trend, while on other stations, no significant trends are found annually. The performance of MK and SR tests was consistent in detecting the trend at different stations.

Abstract: The article mainly conducted a survey of Eco-tourism resources-Binhe Century Square in Mentougou district explored after ecological restoration engineering. The results showed that the total income in Mentougou tourism from 2004 to 2006 had the growth of 36%, total number of tourists had increased by 38%. Satisfaction of visitors for eco-tourism resources of Binhe Century Square by conducting the ecological restoration engineering were reached to 85.67%, and 72.33% of visitors considered the recreation function in parks to be exactly important. The SWOT method was performed for comprehensive analysis on advantage, weaknesses, opportunities and threats aspects of Mentougou tourism resources. The results showed that the own outstanding advantages in tourism resources, geographical location and government tourism policy; the restricted conditions including ecological resources protection, property rights of water resources, land resources and tourism resources; opportunities was existed in improving ecological environment and tourism development tendency supported by the local government; threats were most dried Yongding River and the market competitions. Finally, it should provide the countermeasures of eco-tourism development of Mentougou district in considering about sustainable development, exploring the extensive market, reasonable collocation of tourism resources, performing tourism project and building the tourism facilities.