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1.
为深入研究电气火灾中护套线因过电流诱发短路故障的转化过程,搭建RVVB护套线过电流诱发短路故障电路,统计短路发生概率,借助高速影像,获取短路发生的时间和次数,分析护套线起火燃烧过程。结果表明:在过电流故障发生1 h内,I≤16 A时护套线仅线芯发热、绝缘炭化,无法诱发短路;I=24 A时护套线发生短路概率为40%,在973 s内发生初次短路;32 A≤I<48 A时护套线发生多次短路的概率随电流值增大而增大,在I=48 A时达到50%,发生初次短路的时间随电流值增大而减小,最短时间为28 s;短路引发绝缘层燃烧的概率随电流值增大呈指数递增,I=24 A时护套线在短路后发生燃烧的概率为62.5%,在48 A时达到100%,短路后1 618 ms内火焰可蔓延至护套线两端,形成全线燃烧现象。研究结果可对溯源电气火灾发生的根本原因提供数据支撑。  相似文献   
2.
Gene E. Likens 《Ambio》2021,50(2):278
Early studies published in Ambio showed large-scale acidification of lakes in southern Sweden and Norway from acid rain. These studies were important for delimiting various scientific issues and thus for eventually contributing to legislation, which reduced emissions of sulfur dioxide and nitrogen oxides and helped to mitigate this major environmental problem. Long-term studies and monitoring in Sweden and Norway and at Hubbard Brook Experimental Forest in New Hampshire helped guide this legislation in Europe and in the USA.  相似文献   
3.
基于Fe~(3+)显色技术,建立了测定地表水、地下水、生活污水和工业废水中叠氮化物的高氯酸铁分光光度法。研究结果表明:N_3~-与Fe~(3+)反应生成的棕红色络合物的特征吸收峰为454 nm;氨基磺酸铵可有效掩蔽NO_2~-的干扰,蒸馏能消除色度、CN~-、SCN~-硫化物等对测定的影响;当取样体积为150 mL、蒸馏定容体积为100 mL、使用10 mm比色皿时,方法检出限为0.08 mg/L(以N_3~-计),测定下限为0.32 mg/L;平均回收率为88.0%~104%,相对标准偏差(n=6)为0.3%~5.6%。对实际工业废水样品进行了测定,结果为1.37 mg/L。该方法准确度高、精密度好、操作简单,能够满足水污染物排放标准中叠氮化物的测定要求。  相似文献   
4.
侯晓奎  李元应 《灾害学》2021,(1):60-63,68
绿化树木是园林景观的主体部分,同样也是园林建设中的目标植物。然而,绿化植物容易受到低温寒冻害的影响,进而影响园林布局美观。基于此,该文提出郑州园林绿化树木低温寒冻害空间分布特征研究方法,统计郑州园林绿化树木类型,对各样本按照乔木层与灌木层进行分类整理,将频度、显著度、密度等作为计算树木多样性的指标,分析比较结果,根据获得的比较结果,利用遥感图像采集技术对树木进行分层采样处理,提取受冻害植被颜色特征,通过最佳分割阈值算法分割树木与背景,分别获取两个区域的灰度值。最后采用模板匹配方法将马氏距离作为识别树木受冻害的标准,结合受冻指数,得出空间分布特征与植被分布类型有关,且海拔位置越高受冻害影响越严重。根据获得的空间分布特征结果,可及时采取有效的防治措施,加强对郑州园林绿化树木的保护。  相似文献   
5.
魏宁  刘胜男  魏凤  李小春 《环境科学》2023,44(12):6621-6629
中国水泥行业面临巨大的碳达峰与碳中和压力.CO2捕集利用与封存(CCUS)技术是能够实现化石资源低碳利用的碳减排技术.在中国水泥企业数据基础上,采用全流程CCUS系统模型(ITEAM-CCUS)评估CCUS的碳减排潜力对水泥企业碳中和非常重要.模型从源汇匹配距离、捕集率、CCUS技术和技术水平这4个方面设置了10种情景,完成了水泥行业的企业筛选、场地筛选、CCUS技术经济评估和源汇匹配,初步回答了水泥企业结合CCUS的封存场地、减排规模、成本范围和优先项目分布等关键问题.在250 km匹配距离、85%净捕集率、CO2-EWR技术和当前技术水平情景,44%的水泥企业可以利用CO2强化地下水开采(CO2-EWR)技术开展碳减排,累计年碳减排量为6.25亿t,平准化成本为290~1838元·t-1;具有全流程CO2-EWR早期示范优势的地区为新疆、内蒙古、宁夏、河南和河北等.水泥企业开展全流程CCUS项目技术可行,可以实现大规模CO2减排,低成本项目具有早期示范机会.研究结果可为水泥行业低碳发展和CCUS商业化部署提供定量参考.  相似文献   
6.
唐舒庭  卢一铭  肖盛柏  崔浩  魏世强 《环境科学》2023,44(10):5704-5717
砷(As)和镉(Cd)是稻田土壤中最常见的有毒有害重金属元素,且易从土壤迁移到水稻籽粒中.目前,我国稻田土壤中As和Cd及其复合污染现象普遍,对粮食安全和人体健康均构成了严重威胁.As和Cd在土壤中的环境行为相反,对As-Cd复合污染的同步治理是当前水稻安全生产的关键技术难点.通过综述近年来同步阻控水稻对As和Cd吸收以及转运的若干实用技术,包括水分管理、钝化技术、淋洗技术、电动修复技术、植物修复技术、低累积水稻品种的选取以及叶面阻控技术,归纳并分析了各种技术的处理效果、作用机制和制约因素,提出了主要阻控技术的发展方向,指出构建区域高适配性综合技术模式的重要性,以期为稻田As-Cd复合污染治理和水稻安全生产提供参考.  相似文献   
7.
Artisanal and small-scale gold mining (ASGM) is the principal anthropogenic activity that globally contributes to overloading our environment with mercury. Although the Minamata Convention, led by the United Nations, is a crucial instrument to eliminate its use progressively, novel approaches to accelerate this difficult transition are welcome. This article proposes a framework for policy-making or improvement, fostering the enforcement of mercury elimination through the lens of the 17 Sustainable Development Goals (SDGs), focusing on the excluded artisanal and small-scale gold miners and their dependents. We move forward with a literature review of the Artisanal and Small Mining topic, taking each SDG as a unit of analysis. Understanding the problem as a puzzle of four sets of pieces, namely: (1) social, (2) environmental, (3) economic, and (4) institutional, the paper offers potential opportunities for the decision-makers and practitioners to accelerate the substitution of this heavy metal and develop sustainable futures for the ASGM communities. We conclude by proposing a pragmatic framework that synthesizes the means, actions, and ends to accelerate a sustainable transition.  相似文献   
8.
Wildlife conservation and management (WCM) practices have been historically drawn from a wide variety of academic fields, yet practitioners have been slow to engage with emerging conversations about animals as complex beings, whose individuality and sociality influence their relationships with humans. We propose an explicit acknowledgement of wild, nonhuman animals as active participants in WCM. We examined 190 studies of WCM interventions and outcomes to highlight 3 common assumptions that underpin many present approaches to WCM: animal behaviors are rigid and homogeneous; wildlife exhibit idealized wild behavior and prefer pristine habitats; and human–wildlife relationships are of marginal or secondary importance relative to nonhuman interactions. We found that these management interventions insufficiently considered animal learning, decision-making, individuality, sociality, and relationships with humans and led to unanticipated detrimental outcomes. To address these shortcomings, we synthesized theoretical advances in animal behavioral sciences, animal geographies, and animal legal theory that may help conservation professionals reconceptualize animals and their relationships with humans. Based on advances in these fields, we constructed the concept of animal agency, which we define as the ability of animals to actively influence conservation and management outcomes through their adaptive, context-specific, and complex behaviors that are predicated on their sentience, individuality, lived experiences, cognition, sociality, and cultures in ways that shape and reshape shared human–wildlife cultures, spaces, and histories. Conservation practices, such as compassionate conservation, convivial conservation, and ecological justice, incorporate facets of animal agency. Animal agency can be incorporated in conservation problem-solving by assessing the ways in which agency contributes to species’ survival and by encouraging more adaptive and collaborative decision-making among human and nonhuman stakeholders.  相似文献   
9.
水源地土壤环境质量状况关乎其流域内居民生命健康安全,是生态环境保护研究中的热点科学问题.选择湘东北典型河源区,采集表层土壤样品共87件,通过GIS技术和潜在生态风险指数法研究了土壤重金属(Cd、Pb、Cr、Hg和As)的空间分布特征和潜在生态风险,并采用多元统计分析和正定矩阵因子分解(PMF)模型解释了其可能来源和贡献率.结果表明:①湘东北典型河源区土壤呈酸性,土壤重金属ω(Cd)、ω(Pb)、ω(Cr)、ω(Hg)和ω(As)平均值分别为0.20、41.07、130.51、0.29和11.63mg ·kg-1,对标背景值,除As外均有富集;②土壤重金属综合潜在生态风险为中等风险等级,其中Cr、Pb和As为轻微风险等级,Cd和Hg均为强风险等级;③土壤Cd和Pb具有同源性,主要来源于农业活动,Cr和As受生活垃圾排放和自然母质的双重影响,Hg主要来源于化石燃烧及交通运输;④生活垃圾排放源、自然母质源、化石燃烧及交通运输源和农业活动源对湘东北典型河源区土壤重金属的贡献率分别为21.36%、35.92%、19.30%和23.42%,人为源贡献率大于自然源.研究结果对湘东北典型河源区的污染防治、生态修复和美丽乡村建设具有参考价值.  相似文献   
10.
Urbanization and mass movement of the population from rural areas and small cities to megacities have led to environmental, economic, and social problems in Iran. In dealing with these challenges, assessing resource and environmental carrying capacity (RECC) is considered an effective method to leverage space and capital to achieve sustainable development. This study aimed to rank the provincial RECC in Iran. Toward this purpose, environmental indices were generated from remotely sensed and statistical census data. Then, the provinces were scored in terms of environmental, economic, and infrastructural carrying capacities, and RECC using the mean variance analysis method. Results demonstrated that in most areas, there is no relationship between economic and infrastructural capacities and development. Statistically, a correlation coefficient of −0.53 between economic and environmental carrying capacities indicated excessive use of environmental capacities. Moreover, the spatial distribution pattern of environmental, economic, and infrastructural carrying capacity was entirely heterogeneous between the provinces; there was a northeast–southwest pattern in terms of infrastructural capacity and an economic pattern from north to south. The distribution pattern of RECC is most consistent with the environmental capacity, pointing at the high weight of the indicators of the RECC model. In conclusion, this research offers a new vision for policymakers and provides a theoretical and applicable framework for implementing sustainable strategies in land-use planning. It is recommended that the RECC concept and tools can be used not only for planning but also for measuring the efficiency of spatial development programs and establishing land balances in the region.  相似文献   
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