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991.
本文首先分析了曳引轮绳槽的结构型式对曳引轮绳槽的磨损影响,分别从设计制造阶段、安装调试阶段、日常使用与维护保养阶段三个阶段分析了导致绳槽磨损的原因。接着给出了检查曳引绳的磨损状况、检查曳引轮绳槽的磨损状况和曳引能力的试验三种检测绳槽磨损的方法。最后针对磨损原因的三个阶段分别提出了具体的预防措施。 相似文献
992.
S. Mackinson G. Daskalov J.J. Heymans S. Neira H. Arancibia M. Zetina-Rejón H. Jiang H.Q. Cheng M. Coll F. Arreguin-Sanchez K. Keeble L. Shannon 《Ecological modelling》2009
Fishing mortality and primary production (or proxy for) were used to drive the dynamics of fish assemblages in 9 trophodynamic models of contrasting marine ecosystems. Historical trends in abundance were reconstructed by fitting model predictions to observations from stock assessments and fisheries independent survey data. The model fitting exercise derives values for otherwise unknown parameters that specify the relative strength of trophic interactions and, in some instances, a time series anomaly for changes in primary production. We measured how much better or worse were model predictions when bottom-up forcing by primary production were added to top-down forcing by fishing. Searching for cross system patterns, the relative contribution of fishing and changes in primary production, mediated through trophic interactions, are evaluated for the ecosystems as a whole and for selected similar species in different ecosystems. The analysis provides a simple qualitative way to explain which forcing factors have most influence on modeled dynamics. Both fishing and primary production forcing were required to obtain the best model fits to data. Fishing effects more strongly influenced 6 of 9 of the ecosystems, but primary production was more often found to be the main factor influencing the selected pelagic and demersal fish stock trends. Examination of sensitivity to ecological and model parameters suggests that the results are the product of complex food-web interactions rather than simple deterministic responses of the models. 相似文献
993.
Crowding during the morning peak hours at a platform staircase in a subway station in China was studied in this paper. Passenger flow was surveyed with normal evacuation time recorded. The evacuation process was simulated with the software buildingEXODUS. Predicted results on the total evacuation time and maximum flow capacity of the selected staircase were compared with the field observations. Two parameters, the width of staircase utilized per person and the maximum upstairs walking speed used in the software were identified to be noticeably different from the field studies. Predictions agreed better with the observations after tuning these two parameters. It is concluded that the evacuation simulation software can be applied for safety design with appropriate tuning on the key parameters through field tests. 相似文献
994.
Henglong Xu Wei Zhang Yong Jiang 《Environmental science and pollution research international》2014,21(11):7097-7112
The feasibility for developing a protocol to assess marine water quality based on early colonization features of periphytic ciliate fauna was studied in coastal waters of the Yellow Sea, northern China. The ciliate communities with 3–28-day ages were collected monthly at four stations with a spatial gradient of environmental stress from August 2011 to July 2012. The spatial patterns of both early (3–7 days) and mature (>10 days) communities of the ciliates represented significant differences among the four stations, and were significantly correlated with environmental variables, especially nutrients and chemical oxygen demand (COD). Seven and eight dominant species were significantly correlated with nutrients or COD within the early and mature communities, respectively. The species richness indices were strongly correlated with nutrients, especially in mature communities. These findings suggest that it is possible to assess the status of water quality using early colonization features of periphytic ciliate fauna in coastal waters. 相似文献
995.
Remanufacturing represents a business opportunity and in many cases a means to promote environmental sustainability. To help enterprises economically and effectively implement remanufacturing, a multi-criteria decision making (MCDM) model for selecting remanufacturing technology is developed. The model considers remanufacturing technology portfolios. The enterprise benefits associated with each portfolio, including economic and environmental benefits, are evaluated using six main criteria: cost, quality, time, service, resource consumption, and environmental impact. In addition, the synergies among the different types of technologies for each remanufacturing technology portfolio are also considered. The pair-wise comparison approach of Analytic Hierarchy Process (AHP) is employed for remanufacturing technology portfolio selection. An illustrative example is provided to lend insights into the application of this methodology. 相似文献
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998.
Jing Hu Zuobing Xiao Rujun Zhou Weijun Deng Mingxi Wang Shuangshuang Ma 《Journal of Cleaner Production》2011,19(2-3):221-228
Circular economy (CE) focuses on resource-productivity and eco-efficiency improvement in a comprehensive way, especially on the industrial structure optimization of new technology development and application, equipment renewal and management renovation. The leather industry on the one side boosts the local economic development, on the other side however leads to the tremendous environment pollution and biological chains destruction. The CE model has been implemented as a new way of raw materials, water and energy consumption reduction in the leather industry. Reduce, Reuse, Recycle and Recover of the tannery effluents have been discussed in detail according to the different operation processes. The successful treatment approaches with analysis in the aspects such as wastewater, solid waste, sulfide, Chemical Oxygen Demand (COD), ammonium salt, chloride and chrome of the leather tannery with CE model provide guidance for the sustainable development of leather industry in the future. 相似文献
999.
姜国新 《安全.健康和环境》2012,12(3):30-32
介绍了油气回收技术的基本原理,着重介绍了冷凝膜回收工艺技术的特点,及冷凝膜回收装置在中国石化青岛石油化工有限责任公司轻质油汽车装车的应用情况,分析了存在的问题及改进建议。 相似文献
1000.
Qian Yinghua Zheng Liugen Jiang Chunlu Chen Xing Chen Yongchun Xu Yanfei Chen Yuanping 《Environmental geochemistry and health》2022,44(10):3527-3539
Environmental Geochemistry and Health - This study investigated the environmental geochemical characteristics of rare-earth elements (REEs) in surface waters in the Huainan mining area, Anhui... 相似文献