发动机换环保养应重视磨合

发动机换环保养是指发动机没有达到大修运转极限,气缸磨损也没有达到大修标准,而气缸压力有所下降时,对其进行更换活塞环的工艺过程。在实际工作中我们发现,有些维修人员不按操作规程实施换环,再加上绝大多数发动机的换环保养都是就车进行的,因此忽视了换环保养后的磨合过程。很多人换环保养后就上路正常负重运行,从而造成了一些不良的后果,如:磨损量急剧加大、拉缸、断环、抱缸等。

七种高效畜禽养殖模式(上)

针对中小养殖户不同投资规模和专长,推荐以下7种高效畜禽养殖模式,供广大农户借鉴。一、150标准化养猪模式150标准化养猪模式是指农户建1栋全封闭式标准猪舍(面积220平方米),进行标准化饲养,每批出栏肉猪150头,一年可出栏3批共450头肉猪。该模式综合多项技术集成创新而成,其核心是"良种、良料、良舍、良法"。

Effects of Slow Release Fertilizer on the Yield and Nutrient Use Efficiency of Carnation and Its Environmental Protection Effect

[Objective] The aim was to study the effects of slow release fertilizer on the yield,economic benefit and nutrient use efficiency of carnation and environmental pollution.[Method] Taking carnation（Dianthus caryophyllus）as research object,the application effect and environmental protection effect of slow release fertilizer on carnation were discussed through field plot test.[Result] The main agronomic characters of carnation improved after the application of slow release fertilizer;compared with Conv-F treatment,the yield of carnation with slow release fertilizer increased by 18.67%-20.83%,and its economic benefit increased by 105 500 yuan/hm2,while the ratio of output to input improved by 74.29%;under the same NPK ratio and nutrient amount,the yield,economic benefit and ratio of output to input of carnation after the application of slow release fertilizer increased by 2.11%,14 800 yuan and 16.2%,respectively;besides,the application of slow release fertilizer improved the nutrient use efficiency of carnation,and N,P and K nutrient use efficiency in Opt-F-0.7% treatment increased by 13.88%,8.57% and 30.14% compared with Conv-F treatment.[Conclusion] Slow release fertilizer could not only reduce the waste of fertilizer resources and improve fertilizer use efficiency but also decrease the pollution caused by nutrient loss,which had important practical significance for protecting ecological environment and promoting the sustainable development of agriculture.

发动机活塞环的检验与正确更换

本文通过对部分农机修理部的调查发现:一些维修人员在发动机换环保养作业时存在两种原则性的错误操作,从而导致发动机修后故障率增加,严重影响发动机的动力性和经济性。本文系统地阐明了活塞环检验的方法及常见机型的规范,正确更换活塞环的操作要领。

Effects of sediment and its re-suspension on the growth of Vallisneria asiatica Miki

Aquatic macrophytic growth and its distribution in eutrophic lakes are described in relation to its sediment type and irradiance. Hence, it is necessary to characterize the response of macrophytic growth to lake sediment and its re-suspension. We conducted two independent experiments to measure the effects of sediment and its re-suspension on the growth of Vallisneria asiatica Miki. Based on our study, we conclude that the amount of total biomass of V. asiatica is related, in important ways, to the type of sediment and its re-suspension. According to our comparison, plants and biomass cultured on lake sediments are 2.1 times and 1.5 times greater than that on brown clay from nearby places beside Lake Taihu. The number of plants and the amount of biomass in a turbid water column are smaller than those in a clear water column. The results indicate that the nutrient-rich lake sediments have promoted the growth of V. asiatica, while the re-suspension of the sediment leads to a high turbid level and low light penetration which has a negative impact on the growth of V. asiatica.

Mechanisms and assessment of water eutrophication

Water eutrophication has become a worldwide environmental problem in recent years,and understanding the mechanisms of water eutrophication will help for prevention and remediation of water eutrophication.In this paper,recent advances in current status and major mechanisms of water eutrophication,assessment and evaluation criteria,and the influencing factors were reviewed.Water eutrophication in lakes,reservoirs,estuaries and rivers is widespread all over the world and the severity is increasing,especially in the developing countries like China.The assessment of water eutrophication has been advanced from simple individual parameters like total phosphorus,total nitrogen,etc.,to comprehensive indexes like total nutrient status index.The major influencing factors on water eutrophication include nutrient enrichment,hydrodynamics,environmental factors such as temperature,salinity,carbon dioxide,element balance,etc.,and microbial and biodiversity.The occurrence of water eutrophication is actually a complex function of all the possible influencing factors.The mechanisms of algal blooming are not fully understood and need to be further investigated.

Succession and biodiversity indices in eutrophication process of static landscaping water body in northern China

Many biodiversity indices were used to indicate the biological contamination degree in studies of lake water or seawater. Some were studied on biodiversity comparison for different areas at the same time, or initial structure succession of some aerial lake water systems. The phytoplankton changed with the development of various dominant species. In this study, the dominant species at these stages were Chlorophyta in the beginning stage, Cyanophyta in the second stage, and Xanthophyta in the last stage. Seven of nine biodiversity indices (Margalef's, IE, Shannon-Wiener, Simpson's, McNaughton's, Species and Odds Measure of Diversity) showed their failure to represent the eutrophication trend, and the other two indices (Menhinick's and Monk) exhibited good efficiency to indicate the eutrophication trend for the static landscaping water body.

Water quality characteristics of rivers and ponds in Japan

In Japan, various countermeasures have been taken to improve the water quality of public waters such as rivers and lakes. Though water quality has improved, it is still insufficient. In summer, eutrophication is seen in lakes and inner bays, as well as rivers. As a countermeasure to prevent eutrophication, the removal treatment of nutrient salts such as nitrogen and phosphorus is done, in addition to organic substance elimination in the domestic sewerage system. This report will show the water quality characteristics of rivers and ponds in Japan. It is considered that these investigative results are effective when the water quality improvement of the stabilization ponds where eutrophication occurs are examined in China.

Environmental Footprint of Thermo-Chemical Phosphate Recycling

Three phosphate fertilizers from fossil and secondary starting materials have been assessed for their accumulated environmental footprint. Fertiliser types have been selected for their similarity in terms of phosphate and secondary nutrient concentrations and small waste flows, although significant and unavoidable differences in terms of phosphate solubility remain. Input data were taken from literature and from process simulations in Aspen Plus and HSC Chemistry, being based on evaluations of plants in operation or under construction. It was tested and confirmed that HSC Chemistry data can be directly exported to GaBi as an LCA evaluation tool. The paper shows in two cases a positive energy balance and a rather low environmental footprint of all three assessed processes.

Ecosystem of East Calcutta Wetlands as an Example of Environmental Protection in India

The East Calcutta Wetlands （West Bengal, India） receive the urban sewage of Calcutta. Part of the wetlands is also used as a landfill. A sizeable peri-urban population （some resident, some commuting） are engaged in the area in fishing, agriculture, vegetable farming and garbage recycling activities. The importance of the wetlands is that they maintain the food chain and ecological balance, absorb pollution, treat sewage, and sustain fishes. This study of the Wetlands aimed to： [1） identify the local livelihoods based on use of urban wastewater; （2） estimate the value of direct benefits derived by these stakeholders from its use; and （3） estimate the environmental impact of East Calcutta Wetlands on stakeholders. Three main livelihood options using wastewater were identified： fisheries, paddy cultivation and garbage farming. Use of urban wastewater provides significant income for the poor residing in the wetlands. However adverse environmental and health impacts are occurring as urban expansion is allowed without an understanding of how to preserve the ecological, environmental and economic benefits of the sewage-fed aquaculture system. Focused and directed developmental programs must be devised to protect the East Calcutta Wetlands while improving the living standards of the people residing there.

Developing Agroforestry in Slopelands to Combat Non-point Pollution in China

The status of agricultural non-point source (NPS) pollution in China is quite austere owing to lots of factors, the characteristics of which include severe N, P eutrophications in water bodies, unsuitable structure of agriculture and the lack of reasonable management. It was well known that forest could play an important role to control soil & water erosion, uptake extra soil nutrients as well. However forest coverage is rather low in the headwaters region. The research on the causes of NSP pollution and the significance by developing agroforestry to deal with the problem is presented in the paper, as well as the function of agroforestry and the related measures of pollution controlling, e.g., riparian forest buffer zones building. As a conclusion, controlling the loss of soil and water is regarded as an important crucial action and major research direction in the field. Thereby the benefits of pushing up agroforestry in slops to combat water eutrophication and prevent NSP pollution from worsening are significant.