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1.
Part 2 presents measures at the city scale, which are distinguished into object- and area-related means. The former ones include emission reduction, energy gaining and saving, as well as the climate-improving impact of rooftop and façade greening. Area-related means refer to the reduction of radiation temperature through shading and transpiration as well as impact of urban green areas of different size on the urban climate. Furthermore the opportunities to use subsurface urban heat island as an energy-reservoir for cooling or heating are discussed.  相似文献   

2.
The fluoride concentration in ground water was determined in Sankarankovil block of Tirunelveli district of Tamilnadu (India) where it is the only source of drinking water. Various other water quality parameters such as pH, electrical conductivity total hardness and total alkalinity as well as calcium, magnesium, carbonate, bicarbonate and chloride concentrations were also measured. A systematic calculation of correlation coefficient among different physico-chemical parameters was performed. The analytical results indicated considerable variations among the analyzed samples with respect to their chemical composition. Majority of the samples do not comply with Indian as well as WHO water quality standards. The fluoride concentration in the ground water of these villages varied from 0.66 to 3.84 mg l(-1), causes dental fluorosis among people especially children of these villages. The high and low fluoride containing areas were located using isopleth mapping technique. Overall water quality was found unsatisfactory for drinking purposes without any prior treatment except at few locations out of 50 villages.  相似文献   

3.
An effect of the very patchy distribution of Antarctic krill (Euphausia superba Dana) in various forms of aggregation is that a single swarm may not provide an unbiased estimate of population parameters such as mean length of krill in the local area. Here, we analyse the number of samples required to estimate the characteristics of a local population as precisely as if there were no differences between krill swarms in terms of their biological composition. Krill were intensively sampled over different spatial and temporal scales around South Georgia in 1981 and 1982, and in the Bransfield Strait in 1985. These varied from replicate hauls at a single station over 24 h and repeat sampling in restricted areas over periods of 6 to 14 d to regional surveys around South Georgia and in the Bransfield Strait. Various biological characteristics were measured such as length, maturity, moult stage and feeding state. Depending upon the biological characteristic examined and the area covered by the sampling programme, the number of samples needed to obtain the same degree of precision as would be found in the absence of heterogeneity varied from 3 to > 80 samples. This has important implications for the design of net-sampling programme for monitoring krill populations.  相似文献   

4.
Posidonia oceanica beds form one of the most important coastal ecosystems in the Mediterranean basin and represent a good indicator of the seawater quality, being strongly sensitive to human perturbations. The aim of the present study is to verify whether changes in cytophysiological features of this seagrass could mark early altered environmental conditions. In this context, we investigated in juvenile and intermediate leaves: (1) the presence and structure of phenolic compounds, due to their role in the defence response against biotic and abiotic stress; (2) the presence and distribution of cytokinins, because of their key role in leaf growth and senescence as well as in relation to their interaction in light signalling. Significant and measurable increases in the amount of phenols as well as changes in cytokinins distribution were detected in Posidonia leaves collected from meadows subjected to disturbed environmental conditions as compared to those of preserved ones. These results clearly indicated that these variables could be used as early biomarkers of environmental quality.  相似文献   

5.
采用模拟土柱试验方法,通过连续种植2茬蔬菜,研究7种不同施肥模式[即:不施肥,化肥(基施),化肥(基、追肥各半),化肥+双氰胺(基施),化肥+双氰胺(基、追肥各半),化肥+有机肥(N各半),有机肥(基施)]对蔬菜产量、硝酸盐含量及模拟土柱氮、磷随渗漏水淋溶损失的影响.结果表明,"化肥+双氰胺(基施)"和"有机肥(基施)"2种施肥模式,不仅能使蔬菜获得较高的产量、硝酸盐含量较低,还能明显减少蔬菜种植期间模拟土柱硝态氮、铵态氮和水溶性总磷随渗漏水淋溶的损失量,从而有效减少菜地土壤的氮、磷对地下水造成的农业面源污染.  相似文献   

6.
The alimentary canals of marine herbivorous fishes are variously composed of a few basic structures strung together in series. We model the structures where digestive processes occur as chemical reactors following the model of Penry and Jumars: the stomach as a batch or continuous-flow stirred-tank (CSTR), the intestine as a plug-flow reactor (PFR), and the hindgut caecum as a CSTR. Other structures, where food is mechanically processed-gill rakers, pharyngeal mills, and muscular stomachs-are classified as gates. The optimality criterion for the model is the digestion of the most nutrient in the least amount of time. With the model we are able to predict gut configuration as a function of nutrient concentration and hypothesize that the guts of herbivorous fishes always have a PFR component and may or may not have a CSTR component. The Penry-Jumars model appears to provide a consistent theoretical framework for four main types of digestive mechanisms in marine herbivorous fishes and offers specific testable hypotheses on the feeding ecology and digestive physiology of four representative species of fish as well as other, still unstudied, herbivorous fishes.Contribution No. 68 from the Ocean Studies Institute, Long Beach, California 90840, USA  相似文献   

7.
Low entropy accumulations of matter and energy are more economic for humans to exploit as natural resources. This accumulation of a resource takes place over time and the most concentrated resources, such as fossil fuels, are created over geological ages. As the most concentrated resources become depleted it may be possible for technology to enable the exploitation of less concentrated resources, such as low-grade metal ores or thinly populated fishing grounds. Analysis of the timescales necessary to create different types of natural resource reveals three distinct groups. Further consideration of economic characteristics of resources, including ownership and access, and rate of consumption relative to rate of supply confirms the grouping of resources into the three distinct groups. Rate of change of entropy as a resource is exploited is an indicator of its impact on the environment. Consideration of this again suggests three distinct groups of resources, and this paper identifies them as: continuous natural resources (CNR), such as solar power and wind power; potentially renewable resources (PRR), such as fish and forests; and non-renewable resources (NRR), such as fossil fuels and metals.  相似文献   

8.
Socio-economic development of mankind and well-being depend on the environment and the way in which development influences the environment. Thus, environment and development are interdependent. In fact, economic development is closely linked with the development of resources. These resources can be classified into three categories: public goods, semi-public goods (also known as common property resources) and private goods. In poor countries common property resources make a valuable contribution to the sustainable livelihoods of rural populations. The impact of globalisation on the commons shows various patterns of ownership, control, use and misuse. The commons were subjected to degradation as well as conservation in the process of centralized management in India. After the reform period, the administration of natural resources was given significant attention by specialized departments such as the Forest Department and the Revenue Department. All the land, apart from private land, was regarded as state property and controlled by the state. This paper highlights the need to examine the common property resources sector in the context of wider economic policy reform processes in the Indian economy.  相似文献   

9.
6种观赏植物吸收甲醛能力比较研究   总被引:3,自引:0,他引:3  
城市住宅的室内空气污染十分严重,甲醛已经成为中国目前室内空气中的首要污染物.在已有的报道中,盆栽观赏植物吸收甲醛的效果并未排除盆土的净化能力,由此植物净化效果显然缺乏科学性.选用6种常用室内观赏植物,将盆土与茎叶部分隔开,放入自行研制的甲醛熏蒸箱中,对植物进行熏蒸实验.测得熏蒸前后甲醛的变化量和植物叶面积,以净吸收率及单位叶面积甲醛减少量来比较6种植物吸收甲醛能力的大小.主要结论如下:(1)甲醛质量浓度是国际标准(0.08 mg·m~(-3))23倍情况下,6种观赏植物均能吸收空气中的甲醛,且因种类不同吸收能力大小不一.吸收甲醛能力排序为:广东万年青(Aglaonema modestum)>绿萝(Epipremnum aureum)>垂叶榕(Ficus benjamina)>虎尾兰(Sansevieria trifasciata)>龟背竹(Monstera deliciosa)>四季秋海棠(Begonia semperflorens-hybr.).单位叶面积植物吸收甲醛量依次为:广东万年青绿萝>虎尾兰>龟背竹>垂叶榕>四季秋海棠.(2)甲醛质量浓度是国际标准(0.08mg·m~(-3))57倍情况下,6种观赏植物吸收甲醛能力排序为:垂叶榕>虎尾兰>绿萝>广东万年青>龟背竹>四季秋海棠.单位叶面积植物吸收甲醛量依次为:虎尾兰>垂叶榕>龟背竹>广东万年青>绿萝>四季秋海棠.(3)根据净吸收率及单位叶面积吸收甲醛量的差异,将植物的吸收能力分为两类,吸收甲醛能力较强的植物有:广东万年青、绿萝、虎尾兰、龟背竹、垂叶榕(与空白组相比有显著性差异(P<0.05));较低的植物有:四季秋海棠(与空白组相比无显著性差异).  相似文献   

10.
Tea, Camellia sinensis (L.) O. Kuntze, is grown conventionally (application of chemical fertilizer and pesticides) as well as organically in Darjeeling hills and adjoining plains. Studies on parasitic Hymenoptera gain relevance due to their effective role as biocontrol agents for maintenance of ecological balance and as biological indicators of health of tea agro-ecosystem. Diversity of the hymenopterans was studied using Shannon-Weaver index (1963) both at morphospecies and family levels. The analysis reflected the changing diversity of this group with season, pesticide application and the condition of the tea crop. It further indicated that mainly four parasitoid groups such as braconids, ichneumonids, eulophids and scelionids, showed greater diversity in organic plantation as compared to conventional. Since species (= RTU: recognizable taxonomic unit) diversity and family diversity indices agreed with one another a surrogacy based system (family for RTU) could be adopted for diversity analysis.  相似文献   

11.
Trichloroethylene (TCE) is widely used as an industrial solvent and cleaning fluid. In the present study the toxic effects of TCE inhalation on pulmonary and hepatic biotransformation enzymes in rats have been investigated by assay of aniline hydroxylase (AH), aminopyrine-N-demethylase (APD), benzo-a-pyrene hydroxylase (BH) and glutathione-s-transferase (GST) activities and glutathione (GSH) contents in liver as well as lungs of exposed animals. In both organs phase I and phase II drug metabolizing enzymes have been found to be increased along with decrease in GSH contents following TCE inhalation. Pulmonary as well as hepatic MFO's seem to be activated by inhaled TCE probably in an attempt for its rapid detoxification and reduced glutathione is used during its biotransformation.  相似文献   

12.
Energy and environment are major global issues inducing environmental pollution problems. Energy generation from conventional fossil fuels has been identified as the main culprit of environmental quality degradation and environmental pollution. In order to address these issues, nanotechnology plays an essential role in revolutionizing the device applications for energy conversion and storage, environmental monitoring, as well as green engineering of environmental friendly materials. Carbon nanotubes and their hybrid nanocomposites have received immense research attention for their potential applications in various fields due to their unique structural, electronic and mechanical properties. Here, we review the applications of carbon nanotubes (1) in energy conversion and storage such as in solar cells, fuel cells, hydrogen storage, lithium ion batteries and electrochemical supercapacitors, (2) in environmental monitoring and wastewater treatment for the detection and removal of gas pollutants, pathogens, dyes, heavy metals and pesticides and (3) in green nanocomposite design. Integration of carbon nanotubes in solar and fuel cells has increased the energy conversion efficiency of these energy conversion applications, which serve as the future sustainable energy sources. Carbon nanotubes doped with metal hydrides show high hydrogen storage capacity of around 6?wt% as a potential hydrogen storage medium. Carbon nanotubes nanocomposites have exhibited high energy capacity in lithium ion batteries and high specific capacitance in electrochemical supercapacitors, in addition to excellent cycle stability. High sensitivity and selectivity towards the detection of environmental pollutants are demonstrated by carbon nanotubes based sensors, as well as the anticipated potentials of carbon nanotubes as adsorbent to remove environmental pollutants, which show high adsorption capacity and good regeneration capability. Carbon nanotubes are employed as reinforcement material in green nanocomposites, which is advantageous in supplying the desired properties, in addition to the biodegradability. This article presents an overview of the advantages imparted by carbon nanotubes in electrochemical devices of energy applications and green nanocomposites, as well as nanosensor and adsorbent for environmental protection.  相似文献   

13.
城市污泥超声波处理技术   总被引:14,自引:0,他引:14  
较全面的介绍了超声波处理污泥的效果,以及目前取得的研究进展,并简要讨论了今后的发展趋势。在适当的操作条件下,超声波可以迅速改变污泥结构,释放菌胶团包含水,从而促进污泥减量化和稳定化。高强度的处理也可以加快污泥水解、提高污泥可生化性、提高沼气产量。同时可消毒有害病菌。  相似文献   

14.
该文以泡沫混凝土材料作为外墙自保温材料,结合武汉某住宅建筑实例,借助DeST-h能耗模拟软件,以未保温墙体作为基准模型,通过比较几组不同厚度的自保温墙体,以净现值为评价指标确定了泡沫混凝土自保温墙体的经济厚度;借用minitab16软件的曲线拟合功能,计算分析了泡沫混凝土自保温墙体的最佳经济厚度,为泡沫混凝土作为建筑节能墙体材料进一步发展提供指导性的意见.图2,表3,参7.  相似文献   

15.
新型废水生物脱氮的微生物学研究进展   总被引:18,自引:0,他引:18  
生物脱氮是含氮废水处理公认的最佳处理方式,随着对生物脱氮微生物学原理研究的不断深入,许多新的生物脱氮特殊菌株或菌群及微生物转化机制不断被发现.本文在传统生物脱氮过程机理上,结合最近国内外生物脱氮的新发现,就短程硝化反硝化、同时硝化反硝化、厌氧氨氧化的微生物学原理进行了阐述.图1表2参23  相似文献   

16.
The influence of zinc upon the pattern and success of settlement was examined in the oyster Crassostrea gigas. Late larvae were more tolerant of zinc than embryos. A delay in settlement was recorded in treatments containing zinc as low as 125 μg/l, and numbers of larvae settling was reduced in the presence of zinc. Larvae subjected to zinc immediately prior to settlement showed evidence of slowing in behavioural development. Those larvae which settled in the presence of zinc, however, when ongrown in clean water were as viable as controls. Zinc at concentrations of 250 and 500 μg/l suppressed spat growth, but recovery was rapid upon subsequent on-growing in clean water conditions.  相似文献   

17.
孙兆刚 《生态环境》2012,(3):590-594
生态经济是在生态系统承载能力范围内,运用系统工程方法和生态经济学原理改变生产和消费方式,挖掘资源的潜力,建设体制合理与社会和谐环境的经济形态。生态经济的以资源为基础,以政策与制度为导向,以技术创新为支撑,是制度、技术、资源等重要影响变量协同作用的结果,制度变迁、技术创新、资源利用三者共同作用于生态经济运行过程都呈现出了典型的非线性特征;将制度、技术、资源分别视为生态经济系统的高层、中层和低层子系统,以逻辑斯蒂(Logistic)曲线为基础,建构了生态经济发展的非线性动力学模型;最后以系统论的观点分析了制度、技术、资源与生态经济发展、科学发展观贯彻、和谐社会构建之间的互动关系。  相似文献   

18.
采用2008~2011年湖南省及洞庭湖生态经济区五大生产性服务业年末就业人数以及第三产业生产总值为基础数据,运用现状比较、地区产业相似度、相关系数等方法对洞庭湖地区生产性服务业的发展潜力、产业结构的差异程度及与GDP增长的相关性进行研究分析,发现洞庭湖城市群的生产性服务业已初步形成以岳阳为交通运输、仓储和邮政业、金融保险业中心、益阳为租赁和商务服务业中心,常德为生产性服务业补充的基本格局等特点,并针对对其集聚程度不高、新兴产业竞争力不够等特点提出完善集聚、建立产业链、推动创新加快转型等优化对策.  相似文献   

19.
湖南省许多企业由于仍然受计划经济体制的阴影笼罩,缺乏竞争观念,品牌意识淡薄,导致品牌难上档次,知名品牌缺少.因此,必须整合湖南品牌战略、实施企业形象战略、培育品牌文化战略和实施品牌战略.  相似文献   

20.
洛阳市城市生活垃圾成份分析   总被引:3,自引:0,他引:3  
对洛阳市城市生活垃圾按季节进行了分类,分析了垃圾中碳、硫、挥发分、灰分及水分的含量,测定了垃圾发热量及部分化学元素的含量,为城市生活垃圾的处理提供了科学数据。  相似文献   

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