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191.
湖北省土地整治项目碳效应核算及其分析   总被引:2,自引:1,他引:1  
论文通过构建土地整治项目碳效应分析框架,将土地整治碳效应分为短期碳效应及长期碳效应,其中短期碳效应分为工程施工碳效应及地类转换碳效应,长期碳效应分为农田生态系统固碳效应和农业耕作活动碳效应。以湖北省14个土地整治项目为例,采用碳排放系数法、生态系统类型法等进行整治项目碳效应核算,并计算土地整治项目实施后达到碳平衡所需的时间,对比分析处于不同地貌类型及工程类型区的土地整治项目碳效应及其构成的差异性。研究结果表明:工程施工是土地整治项目碳排放的主要来源,各项目碳排放总量为4 602.00~22 760.81 t,单位面积碳排放为5.18~19.62 t/hm2;地类转换既有碳汇效应,又有碳排放效应;土地整治后,各项目农田生态系统固碳能力增加了412.27~2 794.91 t/a;耕作活动碳排放也较整治前有所增加,增加强度从8.11 t/a至463.76 t/a不等。整治工作后各项目达到碳平衡的时间最少需要2.68 a,最多需要36.66 a。对比分析表明,地形地貌、工程类型虽不是土地整治各类碳效应产生的决定性因素,但却间接地在工程施工难易程度、排灌条件、耕地产能等多方面对土地整治项目区碳效应产生重大影响。  相似文献   
192.
The Indian brick industry is an unorganized sector in which large numbers of migrant women workers are employed. A survey was conducted on 62 women workers working in different brickfields of West Bengal to assess their physiological workload, nutritional profile, total energy expenditure and energy balance. Energy intake was calculated using physiological fuel values of carbohydrate, fat and protein. From the results it is seen that 13% of the sample population falls under severe (grade III) chronic energy deficiency. The average daily consumption of the workers was comparatively lower than their daily energy expenditure, considering the nature of the job which falls under heavy to extremely heavy categories. This negative energy balance is effectively observed in the nutritional anthropometry data. Thus, an immediate ergonomics intervention with better nutrition should be implemented to improve the health status of the workers so they can safely continue to work for a longer period.  相似文献   
193.
分析了造成除尘系统风量阻力不平衡的因素,提出在除尘支管上装设定风量阀来稳定各吸尘点风量,通过实验证明,在除尘管网支管上装设定风量调节阀,可以有效的消除系统阻力不平衡和管网压力波动造成的吸尘点风量偏差问题。  相似文献   
194.
陈岩  高伟  王东  刘永  吴悦颖  郭怀成 《环境科学学报》2016,36(10):3600-3606
人类活动净氮输入(NANI)是影响河流氮输出的重要因素,研究两者的响应关系对制定氮污染的削减策略具有重要意义.基于NANI核算模型,评估了海河流域人为氮输入强度,并采用实测数据估算了同期的河流氮输出,最终得到干旱缺水区河流氮输出对NANI的响应特征.结果表明,海河流域2008—2012年均NANI输入强度为13258 kg·km~(-2)·a~1,化肥施用、食品与饲料输入、大气沉降和农作物固氮分别占76%、17%、5%和2%;在空间分布上,黑龙港运东子流域的NANI负荷最高,达到24238 kg·km~(-2)·a~(-1),最小的是永定河子流域,为5320 kg·km~(-2)·a~(-1);海河流域主要河流的氮通量与子流域NANI输入呈现显著正相关关系(p0.05),NANI变化可解释67%的河流氮通量变化.然而,仅2%的NANI由河流输出,这一比例低于其他地区研究成果,表明缺水地区河流作为氮输出的功能被削弱,河流不是流域氮输出的主要途径.  相似文献   
195.
A model is described for generating hierarchically scaled spatial pattern as represented in a thematic raster map. The model involves a series of Markov transition matrices, one for each level in the scaling hierarchy. In full generality, the model allows the transition matrices to be different at each level, potentially making available a large number of parameters for landscape characterization. The model is self-similar when the transition matrices are all equal. A method is presented for fitting the model to data that take the form of a single-resolution thematic raster map. Explicit analytic solutions are obtained for the fitted parameters. The fitting method is based on a relationship between the hierarchical transitions in the model and spatial transitions at varying distance scales in the data map, a categorical analogy of the geostatistical variogram.  相似文献   
196.
用田间长期定位试验法研究了施肥与地膜覆盖条件下玉米连作在壤质棕壤中有机质的矿化、积累和平衡。结果表明,土壤有机质矿化率在0.0107~0.0438/a之间,施肥与地膜覆盖有利于土壤有机质的积累与平衡,并加快有机质矿化;在本试验各施肥处理中土壤有机质均有所积累;在连年稳定施肥条件下,有机肥的施用会明显提高土壤有机质平衡值  相似文献   
197.
Several attempts for evaluating environmental impact of active agents allowed in organic olive farming against Bactrocera oleae have been made, but very few studies were performed contemporaneously on more than one of them. Insects were chosen as indicators because they are known to react very quickly to environmental perturbations, mainly at the community level. In fact, the coenosis is the functional unit interacting with biotic and abiotic environmental parameters. Seven taxa, known for their sensitivity to habitat alterations, were sampled and grouped in functional groups: predators and parasitoids, phytophagouses and pollinators. The coenotic balance between these two functional groups was analyzed. The study was carried out in an organic olive orchard in the municipality of Terranova da Sibari, Cosenza, Southern Italy. The tested active agents (Azadirachtin, Rotenone, Copper Oxychloride) were sprayed twice (end of September and middle October). During the treatments the population dynamics of all the taxa were knocked-down. No one tested compound seems to be harmless to the entomocoenosis, particularly on phytophagouses and pollinators. In truly organic farming it is necessary to provide natural refuge areas to beneficial insects (i.e. pest antagonists) in which no active agents are sprayed and alternative preys could be found.  相似文献   
198.
Contemporary reports on the energy and environmental benefits of bioethanol have suggested that the cellulosic ethanol is significantly more efficient. To understand the development potential of energy crops in Taiwan, the present study has assessed the resources and cost inputs for the planning, harvesting, transporting, and storing procedures of the first generation energy crops during 2007–2010 with the perspective of LCA. In addition, a field investigation focusing on rice straw, the largest agricultural waste in Taiwan, has been conducted since 2010 to obtain fundamental data.This study further analyzes the first and second-generation feedstocks from the perspective of LCA based on field investigated data. Taiwan has not yet established an ethanol plant; therefore, this study established production data by simulating the production efficiency of an economical scale using parameters obtained through production trials, and proposed an evaluation model for the energy input, GHG, and production costs of bioethanol in Taiwan. The results of this study were cross-compared with foreign literature to explore the development potential of bioethanol in Taiwan. The results indicate that based on the current cellulosic ethanol technology in Taiwan, regarding the energy balance, GHG, and production costs, is less efficient than that of the first generation bioethanol.  相似文献   
199.
多层采空区流场局部动态平衡数学建模分析   总被引:1,自引:0,他引:1  
针对大同矿区浅埋深、多煤层群、近距离、两硬条件下开采形成的多层采空区极易发生自燃的问题,进行风流流场调压分析,以达到控制采空区遗煤自燃及防止有害气体流人工作面的目标.建立了多层采空区流场调压数学模型,得出工作面风压调节的最优参数,结合工程实际分析,确定了多层采空区流场调压需要达到的预期效果.提出多层采空区流场局部动态平衡的调压方法,结合达西线性渗流定律,确定了多层采空区流场达到局部动态平衡的调压允许范围,并提出调压自动控制方法.  相似文献   
200.
碳酸盐-硫酸盐矿物强化垃圾渗滤液厌氧处理研究   总被引:1,自引:0,他引:1  
厌氧消化通常是垃圾渗滤液生物处理的首要环节,但处理效率不高.本研究尝试通过添加碳酸盐、硫酸盐等矿物来提高垃圾渗滤液的厌氧转化效率.研究共设置5组厌氧生物反应器,包括投加硬石膏、方解石、石膏、白云石的反应器及空白对照,考察添加矿物对垃圾渗滤液厌氧消化的影响.从实验结果可以看出,添加矿物的反应器中COD的去除率可以达到75%左右,而空白对照组去除率尚不足60%,添加矿物反应器甲烷产量显著高于对照.从反应器中的p H变化可以看出,矿物的添加可以提高溶液中的p H.研究结果表明,添加碳酸盐/硫酸盐矿物对垃圾渗滤液中的有机物厌氧消化过程具有重要的促进作用.  相似文献   
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