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排序方式: 共有120条查询结果,搜索用时 484 毫秒
41.
玉龙县碳减排效应估算主要包括退耕还林、造林、小水电、替代能源(包括沼气池和太阳能)使用等方面. 其中,造林具有较长期的碳汇功能,会持续提供碳增汇服务功能;替代能源的使用可以有效减少薪柴燃烧,在以农村人口为主的玉龙县,薪柴是主要的取暖和生活能源,故替代能源的使用颇具意义. 以2005年为基准年,小水电和替代能源总的碳减排效应为22.24×103 t,其中小水电碳减排效应为14.43 ×103 t,太阳能碳减排效应为66.24 t,沼气池碳减排效应为7.74×103 t;设定了基准年后林木生长过程以及替代能源使用状况的情景,并进行情景模拟,估算了玉龙县造林在5年内会产生碳汇21.07×103 t,10年内会产生碳汇24.92×103 t. 在研究区总的碳减排效应中,小水电、沼气池以及生态林地都有较大贡献,而经济林和草地的贡献相对较小;与5年情景相比,20年情景中小水电和沼气池的贡献有所上升,而生态林地等的贡献相对下降. 相似文献
42.
推导了交变磁场感应涡电流力数学模型 ,找出了影响涡电流分离效果的几个主要因素。涡电流分离条件实验证明了数学模型的正确性。涡电流分离实验的显著效果表明 ,交变磁场涡电流分离技术作为一项具有十分广阔应用前景的固废资源化技术 ,具有重要的研究意义 相似文献
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Mitigation translocation of nuisance animals is a commonly used management practice aimed at resolution of human–animal conflict by removal and release of an individual animal. Long considered a reasonable undertaking, especially by the general public, it is now known that translocated subjects are negatively affected by the practice. Mitigation translocation is typically undertaken with individual adult organisms and has a much lower success rate than the more widely practiced conservation translocation of threatened and endangered species. Nonetheless, the public and many conservation practitioners believe that because population‐level conservation translocations have been successful that mitigation translocation can be satisfactorily applied to a wide variety of human‐wildlife conflict situations. We reviewed mitigation translocations of reptiles, including our own work with 3 long‐lived species (Gila monsters [Heloderma suspectum], Sonoran desert tortoises [Gopherus morafkai], and western diamond‐backed rattlesnakes [Crotalus atrox]). Overall, mitigation translocation had a low success rate when judged either by effects on individuals (in all studies reviewed they exhibited increased movement or increased mortality) or by the success of the resolution of the human–animal conflict (translocated individuals often returned to the capture site). Careful planning and identification of knowledge gaps are critical to increasing success rates in mitigation translocations in the face of increasing pressure to find solutions for species threatened by diverse anthropogenic factors, including climate change and exurban and energy development. Problemas con la Mitigación por Traslocación de Herpetofauna 相似文献
45.
Growing dissatisfaction with the globalised food system, articulated on the behalf of both producers and consumers, has caused a variety of public debates surrounding the ethics of food production and consumption to become increasingly visible in society over the last two decades. Simultaneously, farmers’ markets (FMs) and other forms of direct marketing have experienced a noteworthy increase in participants, indicating an emerging demand for an alternative to conventional food networks, alternatives that are often perceived as providing a more just and moral relationship to food production and consumption. This study examines consumer and producer motivations for participation in FMs and opinions towards conventional and alternative agriculture in order to elucidate what (if any) values and morals are shared among producers and consumers. This study draws upon the theoretical framework of moral economy to understand whether these shared values suggest FM participants are working to co-create an alternative economy based on “moral” principles such as fairness, justice, and reciprocity. This mixed-methods study consists of consumer surveys (N?=?377) and semi-structured interviews with producers (N?=?17) from five FMs in the state of Delaware. The results suggest that producer and consumer motivations to participate in FMs, particularly a shared emphasis on social value, are indicative of a sense of moral economy. However, this moral economy is complicated by tension towards consumers and the alternative food movement more generally expressed on behalf of producers. 相似文献
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以编制区域循环经济发展规划为主线,概述了我国循环经济发展的总体趋势和资源型城市经济转型试点的接续产业发展规划;探索性地提出制定循环经济产业基地集聚区建设规划的工作思路;强调发挥政府规划和投融资政策的引导作用,以及建立产业政策体系和激励机制的必要性。 相似文献
48.
《International Journal of Sustainable Engineering》2013,6(3):192-200
This paper presents a feasibility study of Marotti oil biodiesel as an alternative to diesel fuel for a compression ignition engine. Marotti oil is inedible and available mainly in the state of Kerala. The oil is extracted from Marotti seeds. However, the high viscosity, poor volatility and cold flow characteristics of many vegetable oils in general, and Marotti oil in particular, can cause problems such as injector coking, severe engine deposits, filter gumming, piston ring sticking and thickening of lubrication from long-term use in diesel engines. These problems can be eliminated or minimised by transesterification of the vegetable oils to form monoesters. Although transesterification improves the fuel properties of vegetable oil, the viscosity and volatility of biodiesel are still worse than for petroleum diesel fuel. Subsequently, Marotti oil was converted into its methyl ester by the process of transesterification. The methyl ester was blended with diesel in various proportions to obtain different blends of Marotti oil with diesel. The performance, emission and combustion characteristics of Marotti methyl ester and its blends with diesel were studied and the results were compared with the base line data generated for diesel operation. Experiments were conducted using an injection timing of 23° before top dead centre (BTDC) and an injection pressure of 205 bar at various power outputs and at a constant rated speed of 1500 rpm. The engine manufacturer specifies an injection timing of 23° BTDC and injection pressure of 205 bar for the standard diesel fuel operation. The heat release rates, maximum rate of pressure rise, ignition delay and combustion duration for these fuel combinations were obtained. From the results obtained, it was observed that the biodiesel produced from Marotti oil and its blends with diesel have slightly reduced brake thermal efficiency and increased smoke, hydrocarbon, carbon monoxide and reduced NO x emissions compared with diesel-only operation. The investigation showed that the B20 biodiesel blend of Marotti oil with diesel produced better performance in terms of higher brake thermal efficiency, lower specific fuel consumption and comparatively lower emissions compared to the other blend ratios considered. 相似文献
49.
《International Journal of Sustainable Engineering》2013,6(2):80-93
This paper reports the results of research conducted to study the fuel properties of Honge oil and blends of its ester and the subsequent testing of these oils in a four‐stroke, single cylinder, water‐cooled, direct injection, compression‐ignition (CI) engine. Experiments were conducted with injection timings of 19, 23 and 27° BTDC at various loads and at a constant rated speed of 1500?rev?min?1. The performance and emission characteristics of Honge oil and Honge oil methyl ester (HOME) blended with diesel, to produce blends designated B20, B40 and B80, were studied. The heat release rates, maximum rate of pressure rise, ignition delay, and combustion duration for these fuel combinations were determined. 相似文献
50.
PAOLO GUIDETTI 《Conservation biology》2007,21(2):540-545
Abstract: Fishing and other human activities can alter the abundances, size structure, and behavior of species playing key roles in shaping marine communities (e.g., keystone predators), which may in turn cause ecosystem shifts. Despite extensive evidence that cascading trophic interactions can underlie community-wide recovery inside no-take marine reserves by protecting high-level predators, the spatial extent of these effects into adjacent fished areas is unknown. I examined the potential for community-wide changes (i.e., the transition from overgrazed coralline barrens to macroalgal beds) in temperate rocky reefs within and around a no-take marine reserve. For this purpose I assessed distribution patterns of predatory fishes, sea urchins, and barrens across the reserve boundaries. Predatory fishes were significantly more abundant within the reserve than in adjacent locations, with moderate spillover across the reserve edges. In contrast, community-wide changes of benthic assemblages were apparent well beyond the reserve boundaries, which is consistent with temporary movements of predatory fishes (e.g., foraging migration) from the reserve to surrounding areas. My results suggest that no-take marine reserves can promote community-wide changes beyond their boundaries. 相似文献