Ecosystem services provided by urban gardens in Barcelona,Spain: Insights for policy and planning

In many European cities, urban gardens are seen as increasingly important components of urban green space networks. We adopt an ecosystem services framework to assess contributions of urban gardens to the quality of of their users. First, we identify and characterize ecosystem services provided by urban gardens. Secondly, we assess the demographic and socioeconomic profile of its beneficiaries and the relative importance they attribute to different ecosystem services. Next we discuss the relevance of our results in relation to critical policy challenges, such as the promotion of societal cohesion and healthy lifestyles. Data were collected through 44 semi-structured interviews and a survey among 201 users of 27 urban gardens in Barcelona, Spain, as well as from consultation meetings with local planners. We identified 20 ecosystem services, ranging from food production over pollination to social cohesion and environmental learning. Among them, cultural ecosystem services (non-material benefits people derive from their interaction with nature) ​ stand out as the most widely perceived and as the most highly valued. The main beneficiaries of ecosystem services from urban gardens are elder, low-middle income, and migrant people. Our results about the societal importance of urban gardens ​were deemed highly relevant by the interviewed green space planners in Barcelona, who noted that our data can provide basis to support or expand existing gardening programs in the city. Our research further suggests that ecosystem services from urban gardens can play an important role in addressing several urban policy challenges in cities, such as promoting stewardship of urban ecosystems, providing opportunities for recreation and healthy lifestyles, and promoting social cohesion. We conclude that urban gardens and associated ecosystem services can play an important ​ in urban policies aimed at enhancing quality of life in cities, particularly if access to their benefits is expanded to larger segments of the population.     

不同无害化处理对污泥中有机组分的影响

以城市污泥为材料,研究了热喷、辐射和堆肥 3 种无害化处理方式对污泥中有机组分形态的影响.结果表明,污泥中的有机组分经过热喷和辐射处理后,易降解物含量增加,难降解物含量降低;而堆肥处理则相反.污泥总氮的 70%~80%是有机氮,热喷、辐射处理使污泥中的有机氮向易矿化态转变,易矿化态氮含量较处理前分别增加 8.0%和 6.5%;而堆肥处理使污泥中的有机氮向难矿化态转变,难矿化态氮含量增加了 4.1%.经热喷、辐射处理后污泥中有机磷的活性显著提高,但堆肥处理降低了污泥中有机磷的活性.热喷、辐射处理使得污泥中水溶性有机物的大分子组分向小分子组分转化,堆肥处理则与之相反.因此,经热喷、辐射处理的污泥的供肥效果优于堆肥处理.     

微波消解ICP-AES法测定城市污水中11种元素

介绍了微波消解电感耦合等离子体发射光谱法测定城市污水中Cu、Zn、Pb、Cd、Cr、Na、Mn、Fe、Ni、Se、Sb等11种元素的方法。在最佳试验条件下,被测元素的检出限为0．004μg／mL～0．12μg／mL,相对标准偏差为1．9％～11％,回收率为93．1％～104％。     

光电协同催化降解水杨酸和苯胺:二氧化钛晶型的影响

以水中水杨酸和苯胺为氧化降解对象,采用光电催化方法,对比研究了其在锐钛型和金红石型2种TiO2薄膜电极上的降解行为．结果表明：1)2种有机物在锐钛型电极上的降解速率大于在金红石型TiO2上的．2)相同条件下,水杨酸在2种电极上的降解速率差别不如苯胺的明显;偏压增高时两种电极的光电催化活性逐渐缩小．3)金红石型TiO2电极具有较高的光电转换效率但其法拉第电流效率较低。     

PPPUE模式及在中国的应用前景探讨

PPPUE是一种全新的应对城市环境问题的模式,这种模式的应用能够充分发挥公共部门、私人部门和第三方的各自优势。本文总结了这种模式的发展过程与基本运作模式,并对PPPUE模式在我国应用的现状、面临的问题以及应用前景作了分析探讨,为解决我国的城市环境问题提供了一种思路。     

Assessing the demand of solid waste disposal in urban region by urban dynamics modelling in a GIS environment

The twentieth century saw a dramatic increase in the production of urban solid waste, reflecting unprecedented global levels of economic activity. Despite some efforts to reduce and recover the waste, disposal in landfills is still the most usual destination. However, landfill has become more difficult to implement because of its increasing cost, community opposition to landfill siting, and more restrictive environmental regulations regarding the siting and operation of landfills. Moreover, disposal in landfill is the waste destination method with the largest demand for land, while land is a resource whose availability has been decreasing in urban systems. Shortage of land for landfills is a problem frequently cited in the literature as a physical constraint. Nonetheless, the shortage of land for waste disposal has not been fully studied and, in particular, quantified. This paper presents a method to quantify the relationship between the demand and supply of suitable land for waste disposal over time using a geographic information system and modelling techniques. Based on projections of population growth, urban sprawl and waste generation the method can allow policy and decision-makers to measure the dimension of the problem of shortage of land into the future. The procedure can provide information to guide the design and schedule of programs to reduce and recover waste, and can potentially lead to a better use of the land resource. Porto Alegre City, Brazil was used as the case study to illustrate and analyse the approach. By testing different waste management scenarios, the results indicated that the demand for land for waste disposal overcomes the supply of suitable land for this use in the study area before the year 2050.     

企业安全教育培训工作初探

针对企业安全教育培训工作的现状 ,就如何开展好企业的安全教育培训工作和安全教育培训的对象、内容、形式、方法及效果进行了探讨。     

基于强度折减法的巷道整体安全系数探讨分析

将有限元强度折减法应用到高地应力下巷道的稳定性评价。选用矩形、直墙半圆拱形、直墙半圆拱加反拱形、马蹄形及圆形等5种巷道常用断面开展计算研究。就上述5种典型断面,利用有限元分析软件ANSYS12.0分析了岩土体折减系数对巷道代表点的位移及围岩塑性区的发展的影响,再现了巷道断面岩土体变形发展过程。通过观察围岩塑性区的发展和巷道控制点的位移突变,求得各断面形状的安全系数并找出其潜在破坏面。根据安全系数的大小和破坏面的位置,能够评定巷道断面设计的合理性,并对施工工艺和支护参数提出改进建议。     

基于CiteSpace的城市空间形态与碳排放关系研究进展

城市空间形态与碳排放的关系是低碳城市建设的理论依据。基于WOS和CNKI数据库，采用CiteSpace软件对1991—2022年城市空间形态与碳排放的关系进行了综述。从发文趋势、合作网络、突现词探测、关键词分析等角度，分析了该领域的发展动态、研究热点，并通过关键词聚类对文献相关内容进行综合解析。结果表明：（1）1991—2022年该领域发文量总体呈上升趋势，在国际重要事件节点上，发文量有大幅上升。（2）中国是该领域发文最多的国家，发文量达34.03%，美国发文中心性最高，为0.48，且国家、机构合作紧密。（3）关键词共现表明探究城市形态对碳排放的影响一直是学术界关注的热点；突现词探测表明研究重心逐渐从与交通碳排放相关的城市空气质量转移到与城市形态和碳排放有关的内容上来。（4）从关键词聚类标签来看，国内外将城市碳排放测算作为重中之重，并通过指标量化城市空间形态分析城市形态对碳排放的驱动作用；通过建立模型定量探讨城市空间形态与碳排放的关系是未来的研究趋势。未来应编制规范的城市层面碳排放清单以提高测算精度、拓宽城市形态与碳排放关系的研究尺度、深入挖掘三维城市空间形态与碳排放的关系。     

Ecological network determination of sectoral linkages, utility relations and structural characteristics on urban ecological economic system

Analyzing the structure and functioning of the urban system revealed ways to optimize its structure by adjusting the relationships among compartments, thereby demonstrating how ecological network analysis can be used in urban system research. Based on the account of the extended exergy utilization in the sector of urban socio-economic system, which is considered as the composition of extraction (Ex), conversion (Co), agriculture (Ag), industry (In), transportation (Tr), tertiary (Te) and households (Do) sectors, an urban ecological network model is constructed to gain insights into the economic processes oriented to sustainable urban development. Taking Beijing city as the case, the network accounting and related ecological evaluation of a practical urban economy are carried out in this study in the light of flux, efficiency, utility and structure analysis. The results showed that a large quantity of energy and resources have to be consumed to maintain the structure and function of a city. The thermodynamic efficiencies of individual sector in Beijing remain at a low level. The social system in Beijing is a highly competitive network, and there are 8 competitive relations and only two mutualistic ones. The Domestic and Agricultural sector are the major controlling factors of the system. Moreover, the assessment results of Beijing are compared with the other three socio-economic systems, Norway, UK and Italy, and the ecological network function and structure comparisons are correspondingly illuminated and discussed. The conclusions indicate that the exergy-based network analysis can be refined to become an integrative tool for evaluation, policy-making and regulation for urban socio-economic system management concerning structure and efficiency at urban levels.