180度双入口脱硫吸收塔的优化模拟

本文针对1000MW超超临界燃煤机组,采用了180度双入口脱硫吸收塔,分别模拟和比较了单双侧进烟时,隔板对流场的分布状况,提出了最佳的布置方式。     

The effects of component dimensions on heat transfer and pressure loss in shell and tube heat exchangers

In this study, the effects of geometric properties such as baffle spacing, baffle cut, sealing strips, gaps between heat exchanger components, number of tubes and tube passes have been investigated for shell and tube heat exchangers (STHE). For this purpose, geometrical dimensions and data of a specific heat exchanger (HE) used in an industrial application have been obtained. The HTRI Xchanger Suite Educational software was utilized to analyze the reference HE, to verify the results of the software and the output temperatures of the fluids, the shell side heat transfer coefficient (HTC) and the pressure loss (PL) values were compared with the experimental data. After confirming that the results of the software were within the acceptable deviation values, the geometric dimensions of the reference design were changed and new analyzes were carried out to examine the effects of several dimension options on the performance of STHE. Results were discussed in a detailed and comprehensive manner via curves.     

烟气脱硫喷淋塔气体旋流实验研究

提出在烟气脱硫喷淋塔烟气进口设置导流板或采用切向进口,使烟气在塔内螺旋流动,以延长停留时间,加强气液湍动接触,并可改善系统的负荷调节适应能力。对不同进口结构的塔内流速分布、压力损失进行了实验研究,得出了旋流强度、压力损失等随导流板角度的变化关系,并将旋流情况与常规的直流进行了比较。     

稠油联合站污水辐流式沉降罐的技术改造

稠油联合站污水辐流式沉降罐存在着技术问题，作者对沉降罐实施以下技术改造措施：油水隔板由２ｍ延长到３ｍ，油水分离室有效沉降容积由１２７ｍ３扩大到１９０ｍ３，油水分离沉降时间由２ｈ延长到３．０２ｈ，增设水力集砂、冲砂、洗砂装置等。使罐的出口水含油率由改造前的１３６５ｍｇ／Ｌ降到改造后的２４５ｍｇ／Ｌ，并且有可能将罐内沉积的油砂及时收集，同时即刻排入罐外的洗砂池内。凡经洗砂池清洗过的油砂含油量均低于０．１％。罐内清砂周期也因此由６个月延长到２４个月，大大降低了油、气、砂对清砂工人的危害，同时也改善了稠油油区的环境，取得了可观的经济效益和社会效益。     

Land Degradation at the Stara Planina Ski Resort

The environmental impacts of ski resorts in the Balkan region are great and can lead to landscape degradation and loss of land functionality. In this study, we present an example of the negative effects of human activities at the Stara Planina ski resort in southeastern Serbia. The objective of this study is detailed analysis of the characteristics of environmental impacts at the Stara Planina. The management of the ski area and ski slope development caused severe degradation of topsoil and native vegetation. The morphological characteristics of the area, lithological properties of the exposed material and climate conditions resulted in various geomorphic impacts, including rills, deep gullies, solifluctions and debris from rock weathering. Significant changes in land usage altered hydrological conditions, resulting in more frequent torrential floods in the downstream sections of the Zubska River and increased the sediment yield. Environmental impacts were analyzed in the immediate and wider zones of the ski resort in accordance with the specific topography and visual exposure. The restoration and erosion control measures have stopped degradation processes and helped to rehabilitate the appearance and functions of the landscape. The results show the importance of considering lithological (the type and characteristics of minerals present) and hydrological (precipitation, water storage capacity of soil, runoff) factors under the conditions of significant changes in land usage. The results of this investigation can contribute to the improvement of planning processes and the implementation of development projects in ski areas.     

底泥的氮、磷释放及其微生物影响的研究

氮和磷在自然界的循环已经引起了人们的关注,一方面因为氮和磷是生态系统中必不可少的营养元素,另一方面过剩的氮和磷会导致水域的富营养化 ,从而使生态平衡遭受破坏.本文综述了水体沉积物中氮和磷受微生物作用进行释放的影响,以及国内外的研究历史和现状.总结了氮磷微生物代谢的特点,并阐述了与传统认识相区别的最新发现和思想.本文试图从理论上说明微生物的氮磷释放机理,通过生物化学和分子动力的角度解释了细菌对氮磷的吸收和释放,即质子动势理论和Pho调控理论.目前,这一领域研究的热点是为了特殊的使用用途对于高效微生物的分离鉴别和组合培养,和对氮磷代谢的影响因素.     

Environmental planning and management for the Assarawat highland region of south-western Saudi Arabia: the traditional versus the professional approach

The environmental planning and management of the Assarawat highlands of south-western Saudi Arabia are currently confronted by difficult problems. Deforestation is caused either by natural or intentional forces. Natural factors are limited to lightning fire and drought, while intentional forces include vandalism caused by the burning or cutting of preserved forests. Such vandalism continues despite the tremendous efforts of afforestation and preservation by several government agencies, especially the Ministry of Agriculture and Water, the National Commission for Wildlife Conservation and Development and by the municipalities of the cities and towns in the region. For centuries, local inhabitants of the Assarawat highlands have successfully established environmental planning and management strategies which balanced the settlements' growth and natural resource uses according to Islamic laws, and the tribal self-government of each settlement and tribal region. Following the establishment of the Kingdom of Saudi Arabia in 1932, the land management system started to change from tribal-based, where every tribe used to manage its local territory, to State authority. The creation of the State witnessed the unification of various fragmented tribes of Saudi Arabia into one government. This meant that environmental planning and management moved from local/regional towards a national control. This investigation proposes that the local/regional planning and management practised by the tribes could be viably utilized today. As in the past, the implementation of these practices could protect the natural environment of the locality and region and regularize their exploitation rationally, as long as vernacular people implement them. Today environmental planning and management need to be based on strategies of local requirements that enable the indigenous people to plan and manage the use of the resources.     

海南西部资源环境一体化研究

传统发展模式引发的资源环境问题迫使人类思考去寻求新的可持续的发展模式,资源环境一体化就是适应此背景的新兴发展理念。以海南西部沙地环境资源化与山区资源环境化的发展实践,实证分析了资源环境一体化的发展模式与发展机制。按资源与环境是可相互转化的这一资源环境一体化理论基础,海南西部干旱与多沙的环境可将其作为旅游资源进行开发,而针对山区资源过度利用的现状,则通过实施设立自然保护区、退耕还林、封山育林等措施实行保护性开发,实现山区资源环境化。重视环境与可持续发展思想、资源与环境的同源性与资源时效性、科学发展与技术进步、环境政策的完善与严格、政府与企业推进是促进资源环境一体化的主要推动机制。     

论生态环境保护督察制度的完善

推进生态环境保护督察往纵深方向发展需要完善生态环境保护督察制度。生态环境保护督察制度建设具备政治支持、实践基础和制度铺垫等条件。完善生态环境保护督察制度建设以习近平生态文明思想为根本遵循,坚持党的领导,突出问题导向,充分发扬民主。应当完善生态环境保护督察领导小组及其办公室、生态环境保护督察组、生态环境部及其区域督察局等生态环境保护督察主体制度,明确生态环境保护督察组享有检查权、处置权、请求协助权、交办权、督察情况述评权、问责建议权等。完善生态环境保护督察制度应当对地方党委、政府及有关部门、党政领导干部落实中央生态文明建设的决策部署、执行生态环境保护法律法规、履行生态环境保护职能等开展督察。生态环境保护督察可以采取集中督察、"回头看"督察、专项督察、常态督察等形式。除常态督察外,生态环境保护督察主要包括督察准备、督察进驻和进行、督察意见和整改、督察结束、督察后处理等环节。     

The role of symbolic capital in stakeholder disputes: decision-making concerning intractable wastes

This paper examines almost 30 years of disputation concerning the disposal of the world's largest stockpile of the toxic organochlorine, hexachlorbenzene. It describes the study of a chemicals company in its attempt to manage the disposal of the toxic waste in a collaborative fashion with government, environmentalists and the local community. The study describes the new processes and structures specifically designed to address the decision-making and the issues of stakeholder perception and identity construction which have influenced the outcomes. Decision-making in such disputes is often theorized from the perspective of the emergence of highly individualized and reflexive risk communities and changing modes and expectations of corporate responsibility as a result of detraditionalization. We argue that the stakeholder interaction in this study reflects competing discourses in which corporate actors prioritize the building and maintaining of identity and symbolic capital rather than an active collaboration to solve the ongoing issue of the waste. As well, issues of access to expert knowledge highlight the relationship between conditions of uncertainty, technoscientific expertise and identity. The events of the study highlight the challenges faced by contemporary technoscientific corporations such as chemicals companies as they must deliver on requirements of transparency and openness, while maintaining technoscientific capacity and strong internal identity. We conclude that the study demonstrates the co-existence of social processes of individualization and detraditionalization with quasi-traditions which maintain authority, thus challenging the radical distinctions made in the literature between modernity and late or reflexive modernity.     

基于三生空间生态服务供给和需求的国土空间规划效益评价研究

国土空间规划是统筹区域资源空间配置、开发管理和布局优化的总体方案,在引领区域协调发展上具有重要意义。国土空间规划必然导致土地利用类型及布局的改变,从而引起经济、社会、生态环境等方面的供给与需求变化。本研究从三生空间耦合协调的角度,通过生态系统服务和人类福祉需求的供需关系,揭示三生空间的供需连接与耦合关系。本研究借助 InVEST模型和生态服务价值当量法对生态系统服务供给与需求进行定量分析,同时引入耦合协调度模型与相对发展度模型,通过对生态系统服务供需变化进行耦合协调类型分析,探究国土空间用地结构调整所产生的供需间的协调关系,并用耦合协调状况对国土空间规划效益进行评价。研究发现,在规划期内宜宾市翠屏区生态系统服务供需总体耦合协调度呈现减小态势。2020-2035年耦合协调度从 0.60降低到 0.59,相对发展度由 1.05减小至 1.01。生态系统服务总体供给盈余明显,但由于供需分布空间差异,城镇地区为主要的供给赤字区域。影响生态系统服务需求的主要因素为环境净化需求,城市化指标对生态系统服务供需相对发展度具有较为普遍的负面影响。     

Application of remote and in situ information to the management of wetlands in Poland

The protection and regeneration of wetlands has been of crucial importance as a goal in ecological research and in nature conservation for some time and is more important than ever now. Knowledge about the biophysical properties of wetlands' vegetation retrieved from satellite images enables us to improve the monitoring of these unique areas, which are otherwise very often impenetrable and therefore difficult to examine, analyze and assess by means of site visits. The Biebrza Wetlands are situated in the North-East part of Poland and are one of the largest areas made up of marshes and swamps in the entire EU. This is still one of the wildest areas and one of the least destroyed, damaged or changed by human impact. However, in the recent decades there have been attempts made to intensify and overexploit the natural resources of the region and implement new agriculture practices in the area. In this period, drainage canals have been built, and a good deal of the area has been drained. The area of this precious ecosystem covers 25 494 ha. This valuable area of peat with unique vegetation species and with very special birds is one of the most valuable areas in Europe and in 1995 was added to the list of Ramsar sites. The investigation of wetlands in the Biebrza River Valley has been carried out at ground level by taking measurements of soil moisture, evapotranspiration, Leaf Area Index, wet and dry biomass and the levels of ground water and meteorological parameters. Also examined were radiative temperature, detailed vegetation mapping, and APAR. For some years the deterioration of peat lands has been noticed due to the drying out of the area and the frequent outbreak of fires. The consequence is the succession of new vegetation and the appearance of new ecosystems. The Remote Sensing Centre in the Institute of Geodesy and Cartography has undertaken the investigation by applying ERS-2.SAR and ENVISAT ASAR of IS2 and IS4 and VV, HH, HV polarization for the purpose of modeling soil moisture and humidity changes of the area under investigation. The investigation also aimed at finding the best biophysical properties of wetlands' vegetation to characterize marshland habitats and its changes. At the same time as registering the microwave data, the optical data from Landsat ETM+, SPOT VEGETATION, ERS-2.ATSR, ENVISAT MERIS, and NOAA/AVHRR have been registered and information about the biomass and heat fluxes as sensible and latent heat has also been calculated. The vegetation indices are calculated from EO satellite data taking into account jointly the features of vegetation responsible for reflection in various bands and combining this information from several spectral bands. Also, the changes in the humidity of the area have been examined by extracting the backscattering coefficients from two SAR images that were taken at a similar period of the year but with a gap of 5 years. The information about soil moisture as retention, soil moisture changes, heat fluxes and evapotranspiration are all very important for estimates of CO(2) sequestration. The ENVISAT images have been obtained for the ESA AO-ID122 project. Also the SMOS and ALOS data will be applied for the Biebrza Wetlands in the future.     

Assessing hygiene and health related improvements of a rural water supply and sanitation programme in northern Ghana

A case control study was carried out to assess hygiene and health related improvements of the Rural Water Supply and Sanitation Programme in the Upper East Region of Ghana. Hygienic improvements were measured in terms of sources of water collection and storage arrangements, waste disposal, hand washing, food storage arrangements, and defecation and practices associated with faeces. The perception of women on the mode of transmission and treatment of selected water and sanitation related diseases were the criteria used to assess health related improvements. Comparison of the results in the programme and non-programme communities indicates that the water and sanitation programme has achieved some degree of success in the areas of water use and water and food storage for the beneficiaries. However, little has been accomplished in changing people's attitude towards the disposal of household, animal and human waste. In addition, the programme has so far been minimally effective in enhancing women's knowledge about the transmission and treatment of water and sanitation related diseases.     

Analysis of Socioeconomic and Environmental Impacts of Waste Stabilization Pond and Unrestricted Wastewater Irrigation: Interface with Maintenance

The effluent from the waste stabilization ponds (WSPs) of the University of Nigeria, Nsukka Campus, is used for irrigation by poor rural farmers. There has been fear that the poorly maintained WSPs and the reuse practices are contributing to environmental degradation and health hazards. In this study the environmental and socioeconomic impacts of the WSPs and reuse were evaluated based on data collected from questionnaires and the literature. The engineering and agricultural properties of soil in the irrigated and nonirrigated areas were compared. Comparison of the health status of the farmers and nonfarmers, of consumers of crops irrigated with wastewater and nonconsumers was performed using Student's t test and the z-score test. The occurrences of diarrhea, typhoid fever, and malaria among the various groups were used as indices. Analyses show that the health status of the farmers and consumers is poorer than those of nonfarmers and nonconsumers at the 5% level of significance. Vegetable cultivation using WSP effluent is a means of sustenance to the farmers and provides an affordable means of satisfying their nutritional deficiencies. However, the poorly maintained WSPs create odor and mosquito nuisances, trap and destroy livestock, and flood nearby compounds with waste debris. At both 1% and 5% levels of significance, communities around the ponds (< 300 m) suffer malaria more frequently than those who live far away (> or = 300 m). Cost-benefit analysis argues in favor of improvement of WSP management and irrigation reuse of wastewater. Dredging of the ponds, training workers and farmers, and adopting appropriate maintenance and monitoring strategies will greatly enhance the socioeconomic status of the urban poor farmers.     

Air pollution control by economic incentives in the U.S.: Policy,problems, and progress

This paper deals with cost-effectiveness of the economic incentive policies of the bubble concept and offset credits relative to the policy of direct regulations of air emissions. The second section discusses single- and multi-plant bubbles, their adoption across regions and industries, the methods used to control emissions and the extent of savings in costs. We conclude that despite the delay resulting from duplication of review of state implementation plans by both the state and the Environmental Protection Agency, the required technological commands, the requirement to model air quality and the restrictions to permit bubbling only in the attainment areas, the policy is progressing successfully and should be encouraged by eliminating the restrictions. The third section analyzes the policy of emission offset credit, trading, and banking which can permit economic growth in nonattainment areas. It reviews the available literature, which deals only with aggregation of offsets across cities instead of individual offset trades. Progress by individual offset trades is analyzed in terms of the number of offsets, their acceptance across regions, the extent of reductions in emissions, and the classification of the offsets into internal and external trades. Comparison of estimated capital costs and prices of individual offsets with direct regulation costs reveals that the former are economical. We conclude that despite the problems of high tradeoff ratios, the short and uncertain life of the emission offset credits and the technological commands, the policy is progressing successfully and should be encouraged further by relaxing restrictions.This paper represents the author's personal views. Neither the Commission nor any member of its staff is in any way responsible for these views.     

Access for all? Barriers to accessing woodlands and forests in Britain

This paper presents results from research that identified and analysed barriers to accessing British woodlands and forests. This paper aims to contribute to an understanding of access and accessibility and to inform the design of policy and management interventions to encourage increased access by under-represented social groups. A brief review of policy and academic literature places the issue of inclusive woodland and forest access in the context of contemporary debates surrounding public health, well-being, diversity and the perceived role of public green space. There follows an analysis of quantitative and qualitative research findings, informing the presentation of a working typology of barriers. The typology is structured around the access needs of various social groups, allowing an analysis of the social distribution of barriers. The findings indicate the deep-seated psychological, emotional and socio-cultural nature of some barriers and highlight the need for carefully designed interventions that may lie outside the conventional remit of woodland management. This paper will be of particular interest to decision-makers and practitioners and to those involved in the design and delivery of policies, programmes and projects aimed at encouraging inclusive use of woodlands, forests and other types of green space.     

中央生态环境保护督察制度回顾与展望

中央生态环境保护督察是党中央、国务院推进生态文明建设和生态环境保护工作的重大制度创新。《中央生态环境保护督察工作规定》于近期正式出台,首次以党内法规形式明确了生态环境保护督察的制度框架、程序规范、权限责任等。从发展历程来看,我国生态环境保护督察大致经历了督企为主、督政督企并举、党政同责三个阶段。生态环境保护督察具有突出政治站位、压实责任,坚持问题导向、强化震慑,突出边督边改、取信于民等基本特征。为强化成果应用,全面准确把握当前我国生态环境保护工作的重点难点,本文设置7个一级指标和18个二级指标对首轮中央生态环境保护督察所指问题的分布特征进行统计分析,初步剖析问题产生原因,并从督察对象、督察内容和督察体制方面对第二轮中央生态环境保护督察进行了展望。     

连栽对杨树人工林林木生长的影响

通过野外调查和室内试验，研究苏北杨树产区相似立地条件下，不同种植代次的杨树人工林树高、胸径、材积和其叶片N、P、K3种营养元素含量的变化特征。结果表明，4年生林树高、胸径和材积从第三代开始出现明显下降，第二代4年生林生长较快，第三代林生长势与第一代大致相同。随栽植代数增加，7年生、10年生林树高、胸径、材积生长呈下降趋势，7年生林的树高、胸径、材积生长量受连栽的影响存在显著差异。不同年生林叶片营养元素受代次增加的影响未显示一定的规律性。     

Does sheep selectivity along grazing paths negatively affect biological crusts and soil seed banks in arid shrublands? A case study in the Patagonian Monte,Argentina

Domestic animals potentially affect the reproductive output of plants by direct removal of aboveground plant parts but also could alter the structure and fertility of the upper soil and the integrity of biological crusts through trampling. We asked whether sheep selectivity of plant patches along grazing paths could lead to negative changes in biological crusts and soil seed banks. We randomly selected ten floristically homogeneous vegetation stands distributed across an area (1250 ha) grazed by free ranging sheep. Vegetation stands were differently selected by sheep as estimated through sheep-collaring techniques combined with remote imagery mapping. At each stand, we extracted 15 paired cylindrical soil cores from biological crusts and from neighboring soil without crusts. We evaluated the crust cover enclosed in each core and incubated the soil samples at field capacity at alternating 10-18 °C during 24 months. We counted the emerged seedlings and identified them by species. Sheep selectivity along grazing paths was largest at mid-distances to the watering point of the paddock. Increasing sheep selectivity was associated with the reduction of the cover of biological crusts and the size and species number of the soil seed bank of preferred perennial grasses under biological crusts. The size of the soil seed bank of annual grasses was reduced with increasing sheep selectivity under both crust and no crust soil conditions. We did not detect changes in the soil seed banks of less- and non- preferred species (shrubs and forbs) related to sheep selectivity. Our findings highlight the negative effects of sheep selectivity on biological crusts and the soil seed bank of preferred plant species and the positive relationship between biological crusts and the size of the soil seed bank of perennial grasses. Accordingly, the state of conservation of biological crusts could be useful to assess the state of the soil seed banks of perennial grasses for monitoring, conservation and planning the sustainable management of grazing lands.     

The Indus Irrigation System,Natural Resources,and Community Occupational Quality in the Delta Region of Pakistan

This study examines the impact of an elaborated irrigation system on the natural resources and society in the deltaic part of the Indus River in Pakistan. Time series information was collected to analyze the ecological and natural resource dynamics, and their impacts on the structure and quality of the occupations of the people in the Indus delta during pre- and post-irrigation system development periods. The information was collected through literature review, reconnaissance, structured questionnaire survey, focus group discussions, and interviews. The findings revealed that the expansion of the irrigation system and the resulting reduction in the downstream flow had their differential impacts on the various segments of downstream ecology and society. Some of the resources, for example the agricultural mudflats have been adversely affected due to the accelerated seawater intrusion that severely impinged on the paddy farms. On the other natural resources like mangroves, the impacts had been both negative and positive. On one hand, the diversity of the mangroves species had deteriorated while on other hand, the mangroves have benefited from such development because of the alleviated pressure of camel grazing as a result of the occupational change on the part of the camel herders. Furthermore, changes in the hydrological regimes had forced the paddy farmers and camel herders to switch to fishing as an alternative source of employment and income. Considering that currently about 87% people are already engaged primarily in marine fishery, this scenario is threatening the sustainability of the fishery resources as well as the livelihoods of all, the traditional and converted fishermen. The findings of the study are therefore meant to advocate the different treatments which should be accorded to the various segments of the downstream ecology and society during the planning of any remedial irrigation projects in order to mitigate the adverse impacts of the previous irrigation development strategies and of any water resources development to be carried out in the future.