Applied Mechanics and Materials Vols. 209-211

Abstract: Many eutrophic lakes are threatened by cyanobacterial blooms. The bloom-forming cyanobacteria are capable of nuisance growth and produce toxins, resulting in serious threats to water safety and human health. This paper summarized physiological and ecological characteristics of bloom-forming cyanobacteria in their annual life cycle, internal regulation mechanisms and environmental factors for blooms formation. In winter, dormant period is regarded as the continuation of cyanobacteria populations, which conserve “seed bank” for the following year. In spring, recruitment can be defined as an inoculation of overwintering cyanobacteria to the pelagic phase after growth recovery under suitable conditions. Temperature, resuspension and bioturbation had been recognized to be the main driving factors for recruitment. Shortly after recruitment, cyanobacteria establish dominance by fast growth rate and colony enlargement strategy. Under suitable meteorological and hydrological conditions, cyanobacterial colonies aggregate and float up to form heavy blooms, which can lead to water supply crisis and ecological disaster. From late autumn, blooms disaggregate and decline. The sinking process is not only a periodic life cycle but also an irregular mechanical movement. Cyanobacteria accumulation areas in late autumn might highly related to the first occurence locality of blooms in the following year. This information could provide valuable information for the prediction and prevention of cyanobacterial blooms, so as to establish a more stable and healthy ecosystem in lakes.

Abstract: Based on the analysis of the field and characteristics of environmental protection in highway and water transportation, the fields of the standardization of environmental protection in highway and water transportation were defined into the environmental protection supervision, environmental protection in traffic planning, infrastructure facility construction and maintenance, passenger and freight transport, and the standard system was positioned as the level of specific trade standards system, including basic and specific standards. By analyzing the intersection among existing standard systems in China and characteristic of highway and water transportation, part of standards of standard system for national environmental protection, engineering construction of highway and water transportation, inland river shipping were used relative standards of standard system for environmental protection in highway and water transportation, and standards for pollution control of shipping were included standards system for environmental protection in highway and water transportation.

Abstract: Recently the researches on ecological super highway remediation technology have risen, but influence degree of invasive plants is not clear. Based on field investigations , 58 vegetations of expressway slope in Henan province were figued up, in which there were 4 invasive plants. Invasive law has been summarized and remediation suggestions have been proposed.

Abstract: Forest-paper integration has lots of effect on ecological environment , mainly including biodiversity, soil erosion, soil quality and non-point pollution，the paper takes bamboo raw material forest base of He Jiang and Na Xi in province Si Chuan as a research，analyzes Plant Diversity by quadrat survey procedure，analyzes land use pattern by remote sense technique，and analyzes physical properties of soil，presents study direction on the forestry-paper integration of raw material forest base.

Abstract: The land use has become the international mainstream and the favorable direction to dispose the municipal sewage sludge in recent years. The heavy metals, however, are the major barrier that limit the land utilization. Batch aerobic composting experiments were conducted to investigate the effect of composting and co-composting with fly ash on the shape of the heavy metals (Ni & Cd) in sludge by using the sawdust to regulate the C/N ratio. Results have shown that co-composting with fly ash can significantly change Ni & Cd species distribution, leading unstable state content of Ni lower than composting only. However, the result is not as good as composting only in terms of Cd. At the same time the fly ash dosage equaling 14% of the dry sludge mass was the optimized quantity to guarantee the lowest exchangeable fraction amount of the two heavy metals.

Abstract: Lead is unique in that man-made sources contribute almost solely to exposure in the post-industrial era.The adverse health effects caused by low-level exposure to Pb have been reviewed. Such health effects include neurological impairment and deficits in the functioning of the central nervous system. Blood lead level is an important index which can measure how seriously children have been exposed to lead. By consulting the papers on the studies of children’s blood lead levels, the sources and influencing factors of blood lead levels of children in China were reviewed in the present paper, meanwhile, some suggestions were provided to decrease the lead contact probability and improve children’s health.

Abstract: A large number of experiments were done in order to find out the main factors which have an influence on the asphalt flue production in asphalt road construction and to master its dangers. The results show that the asphalt flue production varies with heating temperature, heating time, the asphalt thickness and stirring rate significantly. accordingly these are the main factors which influence the asphalt flue production. Further analysis by means of UV spectrophotometer and liquid chromatography shows that the asphalt flue contains serious harm to human body, such as aromatic compounds, alkanes, and sulfur heterocyclic compounds and other substances. therefore some steps should be taken to inhibit the production of asphalt flue for reducing the hazards to construction workers.

Abstract: With the environmental Kuznets curve theory, this paper analyzed the relation between economic growth and environment pollution and took Chongqing in western of China as an example. The results showed that the relation between economic growth and environment pollution in Chongqing appeared the "pour N", that was to say, as the economic growth, the environment pollution in Chongqing would present the trend of "down- rise-down". From the year of 2000, China had been implementing the strategy of "the great development of the west", which led to the worsening environmental pollution as the economic growth. But in recent years, with more capital into the western region for controlling pollution, the environmental had been improved.

Abstract: Seed germination and seedling establishment is a critical stage in the life cycle. Cynodon dactylon and Medicago sativa are two important species using in ecological restoration. Control experiments were employed to test the effects of temperature and humidity on the germination of the two pioneer species. The experiment included three temperature treatment level (15, 20, 25 °C) and four humidity treatment (5, 10, 15, 20 %) with three repeats. Results showed that temperature and humidity had significant effects on the germination of both species seeds. Seed germination of C. dactylon fluctuated with the increasing temperature, but increased with the increasing humidity. The optimal germination temperature and humidity for C. dactylon seeds was 20 °C and 20 % respectively. Seed germination of M. sativa increased with the increasing temperature meanwhile fluctuated with the increasing humidity. The optimal germination temperature and humidity for M. sativa seeds was 25 °C and 10 % respectively. It is critical to provide suitable soil humidity for seed germination in the ecological engineering.

Abstract: The international engineering market is another broad market for domestic construction enterprises. However, due to the complex political, economic and social situation, the international engineering information is dispersive and asymmetric so that this market exists great risks. The hypertextual risk database of international project can provide contractor with useful information channel to realize information sharing and improve the availability of information. Therefore the risk analysis and risk response measures based on the database will exert a tremendous influence on the success of international contract project. This thesis presents a hypertextual organizational model to construct dynamic risk database of international project which can be used to collect and deal with engineering information utilizing computer technology and network technology. Enterprise revenue can be guaranteed and realized by reducing risk loss with effective identification and evaluation of the potential risk of the project.