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1.
本文介绍了加压热煤气脱硫‘北京煤化-SMOVEN’工艺以及工艺研究试验的主要结果。热煤气脱硫小型连续试验装置投入稳定运行,取得了积极的结果,试验验证了SMOVEN工艺的技术合理性和操作可行性,为其工艺放大研究打下了良好基础。  相似文献   

2.
文章分析了高参数小型化的技术路线在机组高效化及节能减排方面的促进作用,针对当前小型低参数热电联产机组能耗较高以及大型燃煤热电联产机组热电负荷难以有效匹配的现状,探讨了小型超临界机组在热电联产领域的发展思路,并对小型超临界发电机组的各项性能指标进行了分析,结果表明小型超临界热电联产机组具有较好的节能减排效果及更好的适应性,未来应用及推广空间较大。  相似文献   

3.
GB19518.1-2004/IEC62086-1:2001<爆炸性气体环境用电气设备电阻式伴热器>中规定的伴热电缆耐潮试验过程繁琐、单个试验周期短但总试验时间长、对时间要求精确,同时需要多个电磁阀(负责控制进水、出水、为伴热电缆供电)、数码管等装置密切配合,对控制精度及系统可靠性要求较高.基于传统的凸轮开关设计的此试验装置结构复杂、调试困难、稳定性差而且时间精度低.而基于单片机控制的耐潮试验装置设计过程简单、调试方便、时间精度高、功能强大且性能稳定.  相似文献   

4.
本文开展了金属/复材混合结构壁板热变形的测试方法研究,针对混合结构从常温20℃到-55℃的热变形行为,采用非接触式光学测试技术获取整个温度历程的热屈曲变形参数,揭示了飞机温度包线下混合结构壁板的热屈曲变形规律。结论:结构离面位移变化是结构屈曲失稳的表现,壁板结构在降温过程中虽然产生屈曲失稳现象,但是结构仍可恢复至正常状态,并未产生后屈曲现象,结构变形的变化斜率在-15℃之后发生了巨大的变化,基本呈现线性关系。  相似文献   

5.
近年来,日本汽车工业发展神速,各种车辆出口到世界各地。为使汽车能在各种环境条件下安全可靠地行驶,必须对汽车进行严酷的环境试验。本文介绍日本明电舍公司所设计的汽车环境试验系统。 汽车环境试验装置包括以下几类: 气候类:高温、低温、全天候及减压环境试验装置 声学类:全消音及半消音试验室 电磁波类:电波暗室及电波屏蔽室 其他类:如模拟日光照射的阳光模拟装置  相似文献   

6.
通过采用现场实测与数值模拟相结合的方法,构建“电气设备负荷-设备温湿度-室内环境参数-室外气象参数”的数值分析模型,本文揭示了江苏地区采用标准化方案建设的110kV模块变电站内部实际热湿环境问题现状和产生机理,确定了多因素影响下内部环境热湿传递过程规律及气流组织分布。结果表明中午12时至下午18时由设备损耗发热导致室内温度具有明显滞后现象,电容器、主变压器损耗发热量周期分别为48h和24h,与损耗发热量变化对应的室内温差分别为3.6℃和5.8℃;研究发现露点温度范围在(23.0~26.0)℃,温度控制阈值应高于露点温度以避免设备凝露;自然通风形式下热羽流现象导致设备上方空间存在积热区,同侧下进上出的通风形式导致气流短路现象。  相似文献   

7.
吴珊  孔令飞  习璐  张沛 《环境技术》2024,(2):127-131
为研究环境温度变化对纵切自动车床热误差的影响,本文以RTS20瑞士型纵切自动车床为试验载体,通过环境温度变化误差(ETVE)试验装置,开展了恒主轴转速(5 000 rpm)变环境温度、变主轴转速(0~8 000 rpm)变环境温度的热误差试验,对环境温度对热误差的影响进行了研究分析。结果表明:在相同主轴转速下,环境温度变化影响着车床结构各部位的温升,进而影响热误差;在随机主轴转速下,主轴轴承等温度测点的温升受转速变化的影响,热误差的增长与关键测点温度具有相同变化周期,但不具有相同变化趋势,即温度快速升高时热误差并不一定也正向增长;空调开启后各测点温度有明显降低,最高降幅可达3℃,热误差随之也有明显降低趋势,最高降幅达6μm。  相似文献   

8.
为保证整套甲醇装置安全平稳长期运行,需要解决在原料负荷低且波动频繁条件下的废热锅炉水质控制问题,吐哈油田公司甲醇厂通过对低负荷工艺条件下废热锅炉给水和炉水水质控制问题进行研究,针对废热锅炉用水水质要求,从给水除氧效果、磷酸根控制、锅炉排污量方面分析了废热锅炉水质不稳定的原因,并提出了针对性的优化措施,实际运行效果表明:优化措施实施后,未出现爆管事故,刺刀外管内壁检查未发现腐蚀及杂质,取得了较好的环境和经济效益。  相似文献   

9.
潘飞  蔡蕾 《环境技术》2011,33(2):45-48
温度-高度试验箱是人工模拟温度-高度综合环境因素的试验装置,其所提供的环境参数及其变化过程必须满足受试品的试验技术条件.了解温度-高度综合温场变化状态,是保证试验达到考核要求的前提.工程技术人员在进行产品的热设计时,需关注温度-高度综合温场变化的特殊性.  相似文献   

10.
文摘     
《工业用环境试验装置》—《冷冻》1986,61(706),43~51(日文):介绍工业用环境试验装置与一般空调及恒温恒湿设备的区别,比较试验箱各种热媒供应方式的优缺点,探讨各种光源的分类以及对降雨和降雪装置的控制要求,讨论了环境试验设备的特点,如宽域控制、多因素同时控制以及跟踪控制等自动控制等。  相似文献   

11.
Fire and logging in nutrient-poor temperate forests with certain ericaceous understory plants may convert the forests into heaths. The process of disturbance-induced heath formation is documented by using examples ofCalluna in western Europe,Kalmia in Newfoundland, andGaultheria (salal) in coastal British Columbia. In a cool, temperate climate, rapid vegetative growth ofCalluna, Kalmia, and salal following disturbance results in increasing organic accumulation (paludification), nutrient sequestration, soil acidification, and allelochemicals. These are thought to be the main reasons to conifer regeneration failure in disturbed habitats. If continuation in forest is a land-use objective, then temperate forests with an ericaceous understory should not be logged unless effective silvicultural methods are devised to control the ericaceous plants and restore forest regeneration. Preharvest vegetation control may be considered as an option. Failure to control the understory plants may lead to a long-term vegetation shift, from forest to heathland, particularly in nutrient-poor sites. Successful methods of controllingKalmia andGaultheria, however, have yet to be developed. While theKalmia- andGaultheria- dominated heathlands are undesirable in Canada and the Pacific Northwest, a wide range ofCalluna heathlands of western Europe are being conserved as natural and seminatural vegetation.  相似文献   

12.
In water stressed regions, water managers are exploring new horizons that would help in long‐range streamflow forecasts. Oceanic‐atmospheric oscillations have been shown to influence streamflow variability. In this study, long‐lead time streamflow forecasts are made using a multiclass kernel‐based data‐driven support vector machine (SVM) model. The extended streamflow records based on tree ring reconstructions were used to provide a longer time series data. Reconstructed data were used from 1658 to 1952 and the instrumental record was used from 1953 to 2007. Reconstructions for oceanic‐atmospheric oscillations included the El Niño‐Southern Oscillation, Pacific Decadal Oscillation, Atlantic Multidecadal Oscillation, and North Atlantic Oscillation. Streamflow forecasts using all four oscillations were made with one‐year to five‐year lead times for 21 gages in the western United States. This is the first study that uses both instrumental and reconstructed data of oscillations in SVM model to improve streamflow forecast lead time. SVM model was able to provide “satisfactory” to “very good” forecasts with one‐ to five‐year lead time for the selected gages. The use of all the oscillation indices helped in achieving better predictability compared to using individual oscillations. The SVM modeling results are better when compared with multiple linear regression model forecasts. The findings are statistical in nature and are expected to be useful for long‐term water resources planning and management.  相似文献   

13.
Urban ecological systems: scientific foundations and a decade of progress   总被引:9,自引:0,他引:9  
Urban ecological studies, including focus on cities, suburbs, and exurbs, while having deep roots in the early to mid 20th century, have burgeoned in the last several decades. We use the state factor approach to highlight the role of important aspects of climate, substrate, organisms, relief, and time in differentiating urban from non-urban areas, and for determining heterogeneity within spatially extensive metropolitan areas. In addition to reviewing key findings relevant to each state factor, we note the emergence of tentative "urban syndromes" concerning soils, streams, wildlife and plants, and homogenization of certain ecosystem functions, such as soil organic carbon dynamics. We note the utility of the ecosystem approach, the human ecosystem framework, and watersheds as integrative tools to tie information about multiple state factors together. The organismal component of urban complexes includes the social organization of the human population, and we review key modes by which human populations within urban areas are differentiated, and how such differentiation affects environmentally relevant actions. Emerging syntheses in land change science and ecological urban design are also summarized. The multifaceted frameworks and the growing urban knowledge base do however identify some pressing research needs.  相似文献   

14.
Urban gardens are important sources of sustenance for communities with limited access to food. Hence, this study focuses on food production in gardens in the Toledo metropolitan area in Northwest Ohio. We administered surveys to 150 garden managers from November 2014 to February 2015 in our attempt to better understand how neighbourhood racial composition and poverty levels are related to staffing and voluntarism, food production and distribution, the development of infrastructure, and the adoption of sustainability practices in urban gardens. The results from 30 gardens are presented in this paper. We used Geographic Information Systems to map the gardens and overlay the map with 2010 census data so that we could conduct demographic analyses of the neighbourhoods in which the gardens were located. Though the gardens were small – two acres or less – up to 46 varieties of food were grown in a single garden. Gardens also operated on small budgets. Food from the gardens was gifted or shared with friends, family, and neighbourhood residents. Gardens in predominantly minority neighbourhoods tended to have fewer institutional partners, less garden infrastructure, and had adopted fewer sustainable practices than gardens in predominantly White neighbourhoods. Nonetheless, residents of predominantly minority and high-poverty neighbourhoods participated in garden activities and influenced garden operations. Volunteering and staffing were racialised and gendered.  相似文献   

15.
Collisions with deer and other large animals are increasing, and the resulting economic costs and risks to public safety have made mitigation measures a priority for both city and wildlife managers. We created landscape models to describe and predict deer-vehicle collision (DVCs) within the City of Edmonton, Alberta. Models based on roadside characteristics revealed that DVCs occurred frequently where roadside vegetation was both denser and more diverse, and that DVCs were more likely to occur when the groomed width of roadside right-of-ways was smaller. No DVCs occurred where the width of the vegetation-free or manicured roadside buffer was greater than 40 m. Landscape-based models showed that DVCs were more likely in more heterogeneous landscapes where road densities were lower and speed limits were higher, and where non-forested vegetation such as farmland was in closer proximity to larger tracts of forest. These models can help wildlife and transportation managers to identify locations of high collision frequency for mitigation. Modifying certain landscape and roadside habitats can be an effective way to reduce deer-vehicle collisions.  相似文献   

16.
ABSTRACT: Sustained interest in and concern about the health status of the aquatic environment has resulted in extensive research focused on (1) effects of pollution on survival, growth, and reproduction of resource species at all life stages; (2) diseases of fish and shellfish, as they may be related to pollution and as they may serve as indicators of environmental stress; and (3) contaminant body burdens in fish and shellfish - their effects on the aquatic animals and their potential effects on humans. Effects, lethal and sublethal, of pollutants on life history stages of fish and shellfish have been documented, as have impacts on local stocks in badly degraded habitats, but as yet there has been no adequate quantitative demonstration of effects on entire aquatic species - probably because of the difficulty in sorting out relative effects of the many environmental factors that influence abundance. Sublethal effects, especially those that result in disease, have been examined intensively, and some diseases and disease syndromes have been associated statistically with pollution. Other pollution indicators (biochemical, physiological, genetic, behavioral, and ecological) have also received some attention, as have body burdens of contaminants in aquatic species. Research, especially that conducted during the past decade, has done much to clarify the many pathways and toxic effects of contaminants on aquatic animals, and has also helped to identify mechanisms for survival of fish and shellfish in the presence of environmental changes caused by human activities.  相似文献   

17.
All major journalism ethical codes explicitly state that journalists should protect editorial copy from undue influence by outside sources. However, much of the previous research on agricultural information has concentrated on what information various media communicate (gatekeeping studies) or communication's role in increasing innovation adoption (diffusion studies). Few studies have concentrated specifically on organizational and structural constraints that might adversely affect agricultural journalists' ethical standards; those that have, focus largely on farm magazines. A study of newspaper reporters who cover agricultural news found that the most pressing ethical concern is the effect of advertiser (agri-business) pressure on editorial copy, and that their concerns in general parallel those of farm magazine writers and editors. The majority reported being in situations in which they might be exposed to advertiser pressure, including pressures to change or withhold editorial copy. Large minorities suggested that advertising pressures affect the overall environment in which agricultural journalists work, and more than one in ten said they allow advertiser pressures to influence editorial decisions. The newspaper reporters who cover agricultural beats showed slightly more resistance to advertiser pressure than did farm magazine editors in a parallel study.  相似文献   

18.
Mapped environmental classifications are defined using various procedures, but there has been little evaluation of the differences in their ability to discriminate variation in independent ecological characteristics. We tested the performance of environmental classifications of the streams and rivers of France that had been defined from the same environmental data using geographic regionalization and numerical classification of individual river valley segments. Test data comprised invertebrate assemblages, water chemistry, and hydrological indexes obtained from sites throughout France. Classification performance was measured by analysis of similarity (ANOSIM). Geometric regions defined by a regular grid and without regard to environmental variables and a posteriori classifications based on clustering the test datasets defined lower and upper bounds of performance for a given number of classes. Differences in classification performances were generally small. The ANOSIM statistics for the a posteriori classifications were around twice that of all environmental classifications, including geometrically defined regions. The hydro-ecoregions performed slightly better for the invertebrate data and the network classification performed slightly better for the chemistry and hydrological data. Our results indicate that environmental classifications that are defined using different procedures can be comparable in terms of their ability to discriminate variation of ecological characteristics and that alleged differences in performance arising from different classification procedures can be small relative to unexplained variation. We conclude that definition procedures might have little effect on the performance of large-scale environmental classifications and decisions over which procedures to use should be based primarily on pragmatic considerations.  相似文献   

19.
Manganese entering impounded water will undergo a cyclic transformation. Oxidation precipitates manganese from top waters. At the bottom of the lake, biological activity will render manganese soluble by both intracellular as well as extracellular activity. The study was made to demonstrate that biological reduction and transformation, organometallic complexation, together with the presence of carbon dioxide and the lowering of pH all have some effect on the solubility of manganese. Dissolved manganese may be brought back to top waters during the lake overturn and therefore deteriorates the water quality.  相似文献   

20.
Zimbabwean provincial plans were instituted to help in the achievement of the national goal of the creation of an egalitarian, socialist and integrated society. The national goal itself was adopted as an antithesis to the dualist society characterised by spatial, economic, social, politican and technological inequalities that Zimbabwe inherited from colonialism. This meant that provincial plans had to play both a functional (or growth allocating/distribution) and a territorial (or redistribution) role.

This paper reviews their role in achieving the national goal by examining their functions, content, structure and methodology. The paper concludes that because of their nature, provincial plans are not suitable tools for the achievement of the national goal.  相似文献   


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