高压天然气管道急抢修技术的应用

该文介绍了高压天然气管道的各种急抢修技术、装备及其应用实例,并指出管道急抢修技术是控制城市燃气供应风险的有效措施之一。     

西气东输与加快上海城市燃气发展的几点思考

西气东输工程就是将我国新疆塔里木和陕甘宁的天然气通过管道输往急需清洁能源的东部地区,以满足东部地区对天然气能源的迫切需要。该文论述了西气东输与加快上海城市燃气发展的几点思考:资源开发与市场开发与长输管线同步建设、天然气价格对市场的影响、天然气高压管线的安全运行与维护、天然气与城市燃气的调峰问题、天然气的互换问题以及燃气行业与政府监管等问题。     

济南市天然气工程与蓝天工程

介绍山东济南市的燃气、天然气供应及空气污染基本情况,天然气输配系统及蓝天工程。     

CNG和LNG作为城市燃气气源的优越性

该文阐述了压缩天然气(CNG)和液化天然气(LNG)供应方式。CNG和LNG不仅可以作为中小城镇供气站的气源,而且可以作为管道天然气供应的过渡方式,城市燃气调峰、抢修的辅助方式。同时进行经济性评价。     

发挥职能 加强协调 积极推进天然气的开发利用

<正> 前言 近年来,济南市燃气事业发展较快,燃气供应由单一液化石油气到液化石油气与人工煤气并举,由两气并举到天然气的引进利用,实现了历史性的飞跃,极大地促进了工业、科学技术以及经济文化的发展,从根本上改变了整个城市的能源结构,提高了市民生活质量,大大改善了城市     

平顶山市天然气工程环境效益分析

介绍平顶山城市燃气现状、规划中的天然气工程概况,以及引进天然气后的环境效益。     

天然气与管道液化气转换技术的探讨

管道液化石油气在我国不少城市中获得广泛采用,但到21世纪我国的能源结构将作较大调整,目标是加快向天然气转换。本文主要介绍液化石油气集中管道供应方式、天然气输配系统以及天然气与管道液化石油气供气的转换。     

天然气供气过程中气体成分的波动对民用燃气器具的影响

针对上海市天然气气源成分波动的特点,对市场上销售和使用的家用燃气灶具和燃气快速热水器进行了测试,得出了市场上销售的家用燃气器具在设计合理的条件下能够同时适应目前供应的两种天然气之结论。     

安全使用天然气

<正>天然气的主要成分是甲烷,其本身具有无毒、热值高、燃烧稳定、对环境污染小等优点,是一种清洁、高效、优质的城市燃气气源。但同人工煤气一样,天然气也具有易燃、易爆的特性,稍有泄漏,遇上明火,就会发生威力巨大的爆炸。所以,在使用天然气的过程中,应注意以下安全事项：室内管道及燃气用具的安装,应由相应安装资质的人员进行；     

济南市城市燃气规划及面临问题的探讨

该文结合济南市城区的特点和燃气供应现状,提出符合城市发展的管网模式和用气指标,制定了济南市城市燃气规划。     

关于城市天然气战略安全的思考

天然气将在上海能源结构中发挥愈来愈重要的作用。能源供应体系的可靠性关系到城市的经济发展和人民生活，在战略上必须十分重视。该文对城市天然气战略安全提出三个方面的意见，对于编制“十一五”规划和指导行业改革有参考价值。     

浅议天然气汽车的安全管理

从近年发生多起天然气汽车事故,建议加强安全管理,主要是明确各部门职责,加强对天然气汽车改装、燃气装置和气瓶的检验和管理、加强对驾驶员培训等方面。     

分布式供能系统在上海推广的探索

随着我国天然气事业的发展,以天然气为一次能源的分布式供能系统成为可能。介绍了分布式供能系统的定义及特点,针对上海现状,归纳了4类适合推广分布式供能系统的场所。     

城市燃气输配管道风险评价指数体系的建立

该文结合上海市燃气输配管网的特点,分析了影响其运行安全性的各种危险因素,建立了城市燃气输配管道的风险评价指数体系,为预防事故提供了依据。     

我国城市供水系统安全保障及应急体系建设的探讨

探讨有效提高城市处置水源和供水突发事件的能力，建立和健全城镇供水的日常安全保障机制和发生紧急情况时迅速有效的应对机制，建设一整套城镇供水安全保障与应急体系，规范和指导城市水源和供水突发事件的应急处置工作。     

几种LNG供气形式在城镇中的应用

从分析LNG的特性和优势方面入手,介绍了LNG在城镇燃气中的应用范围与作用,以及LNG接受站、LNG气化站、撬装式和瓶组式LNG气化站等多种供气形式各自的应用特点。     

The historical development of the Mexico City milk supply system: local and global contradictions

In order to help inform interventions in food supply systems, urban areas, and sustainable development, this paper traces the development of the milk supply system to Mexico City. The co-evolution of urban supply and demand factors with policy objectives is dealt with in three distinct periods. (1) The early 20th century in which milk production became an end in itself of cattle raising, with the introduction of new forage crops and the concept of the ‘dairy basin'. (2) The period of the paternalist state is characterised by policy objectives to support Mexican dairy producers and ensure milk supply to the burgeoning urban population. To these ends, there was increasing government intervention in cattle breeding and production systems, distribution and processing of milk, and the importation of powdered milk from international stocks. (3) The neoliberal period included a retreat of the state from quality control enforcement, the inclusion of imported milk the industrialisation process of products for national sale, and concentration of dairy enterprises into fewer hands. While ealier policy objectives have indeed been achieved, three contradictions pose a threat to the systems sustainability: the disarticulation of national supply and demand by means of the financial attractiveness of imported milk stocks; the now minimal contribution of the urban area to its own milk consumption, and the poor quality of industrialised milk products reaching the consumer. It is expected that the system will persist essentially unchanged in the near future, as the various actors involved each act in their own self-interest. Constructive interventions should focus on the contradictions created by the pursual of previous policy approaches, and necessarily address issues of sustainability at various scales.     

可持续城市水系统风险分析的研究进展

阐述了城市水系统可持续性与风险分析的关系,在国内外风险分析应用于城市水系统的研究现状综述基础上,给出了城市水系统风险分析技术路径,并对今后风险分析在城市水系统中的运用提出建议。     

Risk of bird predation and defoliating insect abundance are greater in urban forest fragments than street trees

Predation by natural enemies is important for regulating herbivore abundance and herbivory. Theory predicts that complex habitats support more natural enemies, which exert top-down control over arthropods and therefore can reduce herbivory. However, it is unclear if theory developed in other more natural systems similarly apply to predation by vertebrate and invertebrate natural enemies across urban habitats of varying complexity. We used plasticine caterpillar models to assess risk of predation by birds and insects, collected leaf-feeding arthropods, and measured herbivory in willow oak trees (Quercus phellos) in two seasons to determine how predation influenced herbivory across urban forest fragments, street trees planted near forest fragments, and downtown street trees. Predation attempts by birds and abundance of chewing folivores were greater on trees growing in urban forest fragments than downtown street trees. Bird predation attempts and herbivory levels were inconsistent for near-forest trees. Predation attempts by arthropods did not statistically vary among the three urban tree habitats. Contrary to expectations based on theory, chewing folivore abundance and herbivory were generally highest on trees growing in urban forests, the most complex habitat we studied, and the habitat where risk of bird predation was greatest. We suggest that urban forest fragments provide better habitat than other urban landscapes for both urban birds and chewing folivores by having greater habitat complexity. Therefore, basal resources, such as availability of suitable habitat, mediate top-down effects on herbivores in cities.