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161.
162.
辛醇／水分配系数是表征有机污染物环境行为的重要参数之一，本文应用于碎片常数计算了１３０余个有机化合物的辛醇／水分配系数对数值，通过计算值与实测值的比较发现，两者之间表现出相当好的一致性，其平均绝对误差为０．１３５，此外，还探讨了该方法应用于不同类型有机污染物时需要注意的问题。 相似文献
163.
《Journal of Environmental Planning and Management》2012,55(4):512-530
Choosing the site for an integrated hazardous waste disposal facility requires an extensive evaluation process to identify the best available disposal location. This location must comply with the requirements of governmental regulations while minimising the economic, environmental, health and social costs. In addition, the local public must be convinced that the hazardous waste disposal facility is required and that all reasonable steps will be taken to make it compatible with the environment. In addition, the location of the facility should be able to reasonably resolve larger issues. This study identifies environmental, economic and social criteria to be considered for the site selection of an integrated hazardous waste disposal facility. The Delphi method was employed in this study to gather information on the site selection criteria for siting a fully integrated hazardous waste disposal facility in Malaysia. The use of an online Delphi survey is useful and effective when both time and costs are limitations in a study, due to geographically dispersed experts. A two-round Delphi survey was employed in this study. The overall findings indicate that environmental criteria should be given priority when locating the facility, followed by the social and economic criteria. 相似文献
164.
《Environmetrics》2017,28(8)
An extended theoretical framework for the continuous population approach to forest inventories is derived. Here, we treat a simultaneous selection of sample points with any prescribed sampling intensity over a continuous population. Different ways to use available auxiliary information, for example, from remote sensing, by selection of approximately balanced or spatially balanced samples are considered. A large data set of spatially continuous individual tree‐level data is used to demonstrate the potential of these theoretical approaches. This study shows new ways to integrate remote sensing information in designs for forest inventory applications, which can significantly reduce the variance of the Horvitz–Thompson estimator for target variables related to the auxiliary information. 相似文献
165.
《Greenhouse Gases: Science and Technology》2018,8(2):379-392
A lab‐scale hybrid membrane separation‐chemical absorption (MS‐CA) system for a post‐combustion process was implemented by combining a hollow‐fibre membrane module and a packed column in series. A solution‐diffusion model and double‐film theory were adopted to investigate the mass‐transfer performance of membrane separation and the chemical absorption process. To determine optimal operational conditions, experiments were conducted to investigate the mass transfer characteristics and CO2 removal of both mono‐staged systems. A hybrid MS‐CA method was studied to measure coupling characteristics and CO2 removal performance of the system. It was found that increasing the pressure and the temperature of the feed gas enhanced the CO2 diffusion property of the membrane module. For a packed column, mass transfer and carbon capture is affected by the liquid‐to‐gas ratio; TMEA = 40°C is considered the optimal condition. For a hybrid MS‐CA system, the optimal CO2 removal efficiency can reach 99.49% at the condition of Pf = 1 MPa, wMEA = 10 wt%. Improving the feed‐gas pressure will increase the CO2 absorption rate of the overall hybrid system. Compared with the mono‐staged method, the hybrid MS‐CA system has a higher stability and efficiency for the post‐combustion process, especially at a relatively low feed‐gas pressure. © 2017 Society of Chemical Industry and John Wiley & Sons, Ltd. 相似文献
166.
We show a substantive problem exists with the widely-used ratio of coefficients approach to calculating willingness to pay (WTP) from discrete choice models. The correctly calculated standard error for WTP using this approach is shown to be undefined. This occurs because the cost parameter's standard error implies some possibility the true parameter value is arbitrarily close to zero. We propose a simple yet elegant way to overcome this problem by reparameterizing the (negative) cost variable's coefficient using an exponential transformation to enforce the theoretically correct positive coefficient. With it the confidence interval for WTP is now finite and well behaved. 相似文献
167.
M. Kansanga P. Andersen D. Kpienbaareh S. Mason-Renton K. Atuoye Y. Sano 《国际发展与全球生态学杂志》2019,26(1):11-24
Following the renewed effort at achieving a new green revolution for Africa, emphasis has been placed on modernizing smallholder agriculture through the deployment of improved inputs especially mechanized technologies. In Ghana, the government has in the last decade emphasized the provision of subsidized mechanized ploughing services to farmers alongside a rapidly growing private sector tractor service market. While mechanized technology adoption rates have increased rapidly, the deployment of these technologies has been without critical analysis of the impacts on production patterns and local agrarian systems. This paper examines the distributional impacts of agriculture mechanization on cropping patterns and farm sizes of smallholder farmers in northern Ghana using Geographic Information Systems (GIS) techniques, and semi-structured interviews with smallholder farmers (n=60). Specifically, comparative analysis of the field sizes and cropping patterns of participant farmers prior to and after the adoption of mechanized technologies was conducted. In-depth interviews were used to contextualize the experiences of smallholder farmers toward understanding how mechanization may be impacting traditional agriculture. Our findings reveal a mechanization paradox in which farm sizes are expanding, while cropping patterns are shifting away from traditional staple crops (pearl millet and sorghum bicolor) to market-oriented crops (maize, rice and groundnuts). This transition we argue, has adverse implications on the cultural dimension of food security, the organization of social life, and climate change adaptation. We recommend a retooling of the current agricultural policy focus to ensure context sensitivity for a more robust battle against food insecurity. 相似文献
168.
Joseph Amankwah‐Amoah 《Sustainable Development》2019,27(5):910-922
The paper examines the silent technological revolution in sub‐Saharan Africa focusing on emerging issues and challenges. In view of the centrality of technology diffusion in fostering local innovations and economic development in developing countries, it is surprising that our understanding of the challenges and opportunities in scaling‐up technologies remains limited. This paper capitalises on the ongoing silent technological revolution in sub‐Saharan Africa to present an overview of how new technologies have been adopted and utilised to achieve sustainability. The study identified a host of factors such as weak regulatory enforcement systems, lack of financial credit availability, and limited banking services, which have created conditions for technological innovations such as mobile phone‐based banking, mPedigree, “cardiopad,” and M‐PEPEA to emerge. The public policy implications and directions for future research are identified and examined. 相似文献
169.
Recent and rapid landscape changes have occurred over large areas in Mediterranean Basin. Wildfires and human activities are the most important disturbances at landscape-level due to their ecological and socio-economic impacts. The increasing demand which society places on the forest landscapes has led us to develop a tool to identify the economic landscape value around natural protected areas. Our research focused on the integration of social, ecological and economic components of landscape management based on stated social preferences and contingent valuation method (CVM). Landscape value research has been motivated by the need to assist land use planning and environmental management.Geographic Information Systems (GIS) have provided new opportunities to spatially distributed modeling of landscape quality. Correlations were found between the representativeness of the landscape and its sense of belonging, and the contingent rating. Landscape with intensive agricultural practices and mining areas were the least preferred landscapes. There was a notable variation in the economic landscape value attributed to the study area based on the considered CVM scenario, ranging from 1,253,075.1 Euros to 3,650,827.8 Euros. We added the geospatial allocation of willingness to pay according to five landscape quality categories. Our approach could be used to identify priority areas for conservation based on maximizing landscape value, and would be useful in detecting interesting or conflict areas associated with new management and planning alternatives. In this sense, this approach offers managers to seek territorial management strategies to increase economic efficiency in the allocation of resources. 相似文献
170.
Injecting CO2 into oil reservoirs could improve recovery and facilitate the storage of CO2. For developing countries, especially China, coupling enhanced oil recovery (EOR) and CO2 storage becomes an economical and environmentally safe method. Daqing Oilfield is the biggest oilfield in China. It has been operational for 50 years, and has faced many EOR challenges. In this study, a CO2 storage and EOR evaluation method is introduced to calculate the CO2 storage potential in the Daqing Oilfield. The stream tube simulation method and the mixed cell mesh method are adopted to determine the storage coefficient, recovery factor, and MMP (minimum miscible pressure). The evaluation results of the Daqing Oilfield show that most of the oilfields in Daqing can carry out CO2 immiscible flooding. For EOR effects, the CO2 miscible flooding can improve oil recovery by about 9%. The average CO2 storage factors are 0.4 for miscible flooding while the immiscible flooding is 0.28; miscible flooding has better CO2 storage capacity and EOR potential. The results show that injecting CO2 into the reservoirs in Daqing Oilfield is a win‐win technology. © 2015 Society of Chemical Industry and John Wiley & Sons, Ltd 相似文献