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91.
Road-related erosion was estimated by measuring 100 randomly located plots on a 180 km road network in the middle reach of R'dwood Creek in northwestern California. The estimated erosion ratn of 177 m3 km-1 was contrasted with two earlier studies in nearby parts of the same watershed. A sizable proportion of the great reduction in erosion from that reported in the earlier studies is attributed to changes in forest practice rules. Those changes have resulted in better placement and sizing of culverts and, especially, to less reliance on culverts to handle runoff from logging roads.  相似文献   
92.
● Established a quantification method of pollutant emission standard. ● Predicted the SO2 emission intensity of single coking enterprises in China. ● Evaluated the influence of pollutant discharge standard on prediction accuracy. ● Analyzed the SO2 emissions of Chinese provincial and municipal coking enterprises. Industrial emissions are the main source of atmospheric pollutants in China. Accurate and reasonable prediction of the emission of atmospheric pollutants from single enterprise can determine the exact source of atmospheric pollutants and control atmospheric pollution precisely. Based on China’s coking enterprises in 2020, we proposed a quantitative method for pollutant emission standards and introduced the quantification results of pollutant emission standards (QRPES) into the construction of support vector regression (SVR) and random forest regression (RFR) prediction methods for SO2 emission of coking enterprises in China. The results show that, affected by the types of coke ovens and regions, China’s current coking enterprises have implemented a total of 21 emission standards, with marked differences. After adding QRPES, it was found that the root mean squared error (RMSE) of SVR and RFR decreased from 0.055 kt/a and 0.059 kt/a to 0.045 kt/a and 0.039 kt/a, and theR2 increased from 0.890 and 0.881 to 0.926 and 0.945, respectively. This shows that the QRPES can greatly improve the prediction accuracy, and the SO2 emissions of each enterprise are highly correlated with the strictness of standards. The predicted result shows that 45% of SO2 emissions from Chinese coking enterprises are concentrated in Shanxi, Shaanxi and Hebei provinces in central China. The method created in this paper fills in the blank of forecasting method of air pollutant emission intensity of single enterprise and is of great help to the accurate control of air pollutants.  相似文献   
93.
Disinfection by-products (DBPs) are regulated in drinking water in a number of countries. This critical review focuses on the issues associated with DBP regulatory compliance, including methods for DBP analysis, occurrence levels, the regulation comparison among various countries, DBP compliance strategies, and emerging DBPs. The regulation comparison between China and the United States (US) indicated that the DBP regulations in China are more stringent based on the number of regulated compounds and maximum levels. The comparison assessment using the Information Collection Rule (ICR) database indicated that the compliance rate of 500 large US water plants under the China regulations is much lower than that under the US regulations (e.g. 62.2% versus 89.6% for total trihalomethanes). Precursor removal and alternative disinfectants are common practices for DBP regulatory compliance. DBP removal after formation, including air stripping for trihalomethane removal and biodegradation for haloacetic acid removal, have gained more acceptance in DBP control. Formation of emerging DBPs, including iodinated DBPs and nitrogenous DBPs, is one of unintended consequences of precursor removal and alternative disinfection. At much lower levels than carbonaceous DBPs, however, emerging DBPs have posed higher health risks.  相似文献   
94.
阐述了近几年来全国南方集体林区重点林业县的福建省尤溪县在发展林业产业、调整林业产业结构、推进林业产业化进程、生产安全中所取的成效,以及存在的问题,并以此提出今后集体林区林业产业发展的指导性、实用性的对策与建议。  相似文献   
95.
设计了火电厂实施2003版排放标准和2011版排放标准两种排放情景,运用Models-3/CMAQ模型系统分别模拟各情景到2015年的硫、氮沉降量,探讨2011版火电排放标准对我国大陆地区酸沉降的影响.研究表明,2011版火电标准能够有效改善我国的硫沉降状况,相比于实施2003版标准,2011版标准实施后至2015年我国大陆硫沉降总量降低了18.58%,年均硫沉降强度大于3.2t/km2的面积减少了86.40%;2011版火电标准对我国氮沉降状况也起到了一定的改善作用,标准实施后到2015年我国大陆氮沉降总量降低了9.28%,年均氮沉降强度大于4.0t/km2的面积减少了27.27%.  相似文献   
96.
余辉 《环境科学研究》2014,27(11):1243-1250
琵琶湖富营养化全面有效的控制得益于对流域污染源的系统控制. 琵琶湖流域污染源系统控制包括通过立法与监管严格控制工厂与企业的污水排放、城镇污水管网与大型污水处理设施的高度覆盖、农业集落污水处理设施的全覆盖三部分,流域污水处理系统的全覆盖及高度处理技术的普及是其最为成功的经验之一. 琵琶湖流域城镇下水道普及率达86.4%,主要污染物——TN、TP及CODMn的去除率分别高达90.0%、98.7%及94.6%. 琵琶湖流域同时实施了净化槽普及、设置农业集落排水处理设施、初期雨水净化处理及农田循环灌溉等具有地方特色的面源治理对策. 通过综合治理,琵琶湖主要入湖污染负荷明显减少,与1985年相比,2012年CODMn点源污染负荷减少了76.8%,TN减少了45.5%,TP减少了65.6%. 与之比较,我国的湖泊治理存在的问题主要包括有针对性的地方排放标准的缺失及执法力度的不足、城镇污水深度处理及运营管理技术上的差距、面源污染对策的严重不足.   相似文献   
97.
目前,新会计准则在我国上市公司中实施已有六年多时间,然而在我们衡阳市企业中的运用情况如何,企业的反映如何,在实施过程中有哪些问题和难题,这些都是普遍关注的问题.因此,为进一步了解新会计准则的实施情况,发现并解决实施过程中存在的问题和难题,课题组对衡阳市相关企业的新会计准则实施情况进行了调查和分析.参8.  相似文献   
98.
Soft systems thinking and social learning for adaptive management   总被引:1,自引:0,他引:1  
The success of adaptive management in conservation has been questioned and the objective-based management paradigm on which it is based has been heavily criticized. Soft systems thinking and social-learning theory expose errors in the assumption that complex systems can be dispassionately managed by objective observers and highlight the fact that conservation is a social process in which objectives are contested and learning is context dependent. We used these insights to rethink adaptive management in a way that focuses on the social processes involved in management and decision making. Our approach to adaptive management is based on the following assumptions: action toward a common goal is an emergent property of complex social relationships; the introduction of new knowledge, alternative values, and new ways of understanding the world can become a stimulating force for learning, creativity, and change; learning is contextual and is fundamentally about practice; and defining the goal to be addressed is continuous and in principle never ends. We believe five key activities are crucial to defining the goal that is to be addressed in an adaptive-management context and to determining the objectives that are desirable and feasible to the participants: situate the problem in its social and ecological context; raise awareness about alternative views of a problem and encourage enquiry and deconstruction of frames of reference; undertake collaborative actions; and reflect on learning.  相似文献   
99.
工作安全分析(简称JSA)作为有效的危害识别和风险控制工具被广泛使用,但基层班组员工所做JSA的质量一直不高,具体表现为员工虽然清楚JSA的各个环节,却不能高质量的完成.尽管这在一定程度上与基层员工文化素质低,文字表达能力差有关,但也是管理者缺乏具体和优秀的指导所致.针对实施JSA的各个环节,分析制约质量提升的具体原因,以标准规范为基础提出具体可行的改进措施,实施效果良好.  相似文献   
100.
Domestic energy practices are a topical policy issue, with implications for climate change, energy security and fuel poverty. Accordingly, a growing body of literature examines ways of promoting energy conservation and generation by individuals. However, there has been relatively little discussion of how status and stigma are implicated in these practices, and may act as facilitators or barriers to “behaviour change”. To help address this gap, this article draws both on existing literature and a new UK-based study of people who are attempting to live sustainable lives, to provide insights into how domestic energy practices may be status-enhancing or stigmatising, and how these risks and opportunities can be managed. While energy practices are often understood as “inconspicuous”, it is argued here that in some circumstances individuals may actively manage the visibility of their energy practices. The discussion considers these findings with regard to social power relations, and identifies issues warranting further exploration within the emerging research agenda on energy and equity.  相似文献   
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