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181.
Single and joint effects of petroleum hydrocarbons and cadmium on the
polychaete Perinereis aibuhitensis Grube 总被引:1,自引:1,他引:0
Using the concentration gradient and combined pollutant exposure method, the single and joint effects of petroleum hydrocarbons (PHCs) and cadmium (Cd) on polychaete Perinereis aibuhitensis Grube, an ecologically keystone species in estuarine and coastal environment, have been investigated. The results indicate that the toxicity of PHCs to P. aibuhitensis is stronger than that of Cd to the organism. There are positive correlations between the mortality of worms and the exposed concentration of single Cd or PHCs in solution. Similarly, the accumulation of Cd or PHCs in worms increased with increasing Cd- or PHC-exposed concentrations. All the correlation relationships can be described using unitary quadratic equations (Y or Z = aX^2 + bX + c). It is calculated, on the basis of these expressions, that the median lethal dose (LC50) ofP aibuhitensis exposed to a single Cd or PHCs is 793.4-13567.3 and 28.0-119.9 μg/L, respectively. The exposed time has some stimulative effect on the two pollutants and on the mortality of the worms. Thus, even a low concentration of a single Cd or PHCs may have strong toxic effects on the worms when the exposed time becomes longer. The accumulation of Cd or PHCs in worms differs with an increase in exposure time at the given exposed concentration of a single Cd or PHCs. Noticeably, the accumulation of PHCs in worms decreases with an increase in exposure time at the given high concentration of PHCs in solution. The joint effect of PHCs and Cd on P. aibuhitensis is very complicated and changes with the exposed concentrations of the two pollutants. At the given concentration of PHCs, the joint toxicity of the two pollutants on the worms changes from synergism to antagonism with an increase in Cd concentration. The accumulation of Cd in the worms significantly decreases with the addition of PHCs to exposure solution. 相似文献
182.
采用盆栽实验的方法,研究了重金属(包括Cu、Zn、Pb和Cd)复合污染和接种丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)Glomus mosseae对蚕豆(Vicia faba)生长及DNA损伤的影响。结果表明,虽然接种菌根真菌对蚕豆生物量的影响并不显著,但是却显著影响植物对重金属的吸收,接种菌根真菌对蚕豆吸收4种重金属元素的作用有差异。采用单细胞凝胶电泳(single cell gel electrophoresis,SCGE)法研究接种菌根真菌对蚕豆叶片的DNA损伤的影响,与重金属吸收的结果相吻合。结果表明,接种处理可显著增加蚕豆叶片的DNA损伤程度,这与接种处理可提高植物的重金属吸收相一致。 相似文献
183.
184.
《International Journal of Sustainable Engineering》2013,6(4):332-343
Appropriate maintenance can prolong the life of an asset and prevent costly breakdowns that may result in lost production, failed shipping schedules and a decline in customer satisfaction. The goal of this study was to present a comprehensive framework that utilises sustainability metrics based on social, environmental and economic criteria to select an appropriate maintenance strategy among a variety of maintenance strategy alternatives, such as preventive, failure-based, reliability-centred, condition-based and total productive maintenance strategies, for a manufacturing company. The sustainability-based approach may significantly influence the personnel, energy, material and the overall costs in a company. In the first step of this paper, a sustainability-based decision-making structure is proposed for the maintenance strategy selection problem applying the concept of factor analysis to determine the leading factors in each of the sustainability pillars. In the next step, a fuzzy VIKOR framework is used to select the most appropriate maintenance strategy. The provided approach is illustrated using a manufacturing industry case study. 相似文献
185.
介绍了气力输送系统在电厂660MW机组除灰中的应用,并对飞灰特性,以及除灰系统设计、关键技术运用、运行情况、设备维护和故障处理等问题进行了分析论述。 相似文献
186.
187.
Integrating soil carbon cycling with that of nitrogen and phosphorus in the watershed model SWAT: Theory and model testing 总被引:1,自引:0,他引:1
Armen R. Kemanian Stefan Julich Valipuram S. ManoranjanJeffrey R. Arnold 《Ecological modelling》2011,222(12):1913-1921
In this paper we describe and test a sub-model that integrates the cycling of carbon (C), nitrogen (N) and phosphorus (P) in the Soil Water Assessment Tool (SWAT) watershed model. The core of the sub-model is a multi-layer, one-pool soil organic carbon (SC) algorithm, in which the decomposition rate of SC and input rate to SC (through decomposition and humification of residues) depend on the current size of SC. The organic N and P fluxes are coupled to that of C and depend on the available mineral N and P, and the C:N and N:P ratios of the decomposing pools. Tillage explicitly affects the soil organic matter turnover rate through tool-specific coefficients. Unlike most models, the turnover of soil organic matter does not follow first order kinetics. Each soil layer has a specific maximum capacity to accumulate C or C saturation (Sx) that depends on texture and controls the turnover rate. It is shown in an analytical solution that Sx is a parameter with major influence in the model C dynamics. Testing with a 65-yr data set from the dryland wheat growing region in Oregon shows that the model adequately simulates the SC dynamics in the topsoil (top 0.3 m) for three different treatments. Three key model parameters, the optimal decomposition and humification rates and a factor controlling the effect of soil moisture and temperature on the decomposition rate, showed low uncertainty as determined by generalized likelihood uncertainty estimation. Nonetheless, the parameter set that provided accurate simulations in the topsoil tended to overestimate SC in the subsoil, suggesting that a mechanism that expresses at depth might not be represented in the current sub-model structure. The explicit integration of C, N, and P fluxes allows for a more cohesive simulation of nutrient cycling in the SWAT model. The sub-model has to be tested in forestland and rangeland in addition to agricultural land, and in diverse soils with extreme properties such high or low pH, an organic horizon, or volcanic soils. 相似文献
188.
航空维修差错模式及差错成因的灰色关联分析 总被引:3,自引:2,他引:1
提出一种基于HFACS-ME框架和灰色关联分析法的航空维修差错模式和差错成因之间关系的分析方法。利用该方法分别从"模式—成因"和"成因—模式"2个方向,以"技能差错"和"身体状态差"为例,对差错模式和差错成因之间的关系进行分析,得到影响"技能差错"的主要差错成因依次为空间狭窄、培训不足、工具损坏、身体状态差、精神状态差、空间阻碍,以及"身体状态差"主要影响的差错模式为记忆差错、决策差错、技能差错。结果表明,灰色关联分析法对航空维修差错模式和差错成因之间关系的分析是有效的、可行的。 相似文献
189.
基于模糊数学的机务维修中人的可靠性综合评价 总被引:1,自引:0,他引:1
基于有关资料数据统计、现场调查研究和理论分析,结合许多专家在人为因素上的研究成果,建立了机务维修中人可靠性评价指标体系,应用层次分析法(AHP)确定了各指标权重.运用模糊综合评价原理构建了机务中人的可靠性模糊综合评价模型,并进行了实例验证,得出了可靠性的综合评价等级.结果表明,该方法简单,易操作,能实现动态的综合评价,... 相似文献
190.
This study determines the factor structure of safety climate within a road construction organization using a modified version of the safety climate questionnaire (SCQ). It also investigates the relationship between safety climate and safety performance. The SCQ was administered to 192 employees from two districts and in two job categories — construction and maintenance. A behavioural observation measure of safety performance was also developed. Factor analysis derived six factors, which were similar to those obtained in an earlier study using the SCQ. Differences in the safety climate of job sub-groups were found on two of the factors. No differences between the two districts were found. No relationship was found between safety climate and the safety performance measure. While identical safety climate factors cannot apply to all organizations, some general safety climate factors may emerge. Discussion focuses upon the measurement of safety climate. 相似文献