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排序方式: 共有1002条查询结果,搜索用时 15 毫秒
851.
《Journal of environmental science and health. Part. B》2013,48(5-6):871-887
Abstract A lab-scale composting experiment was carried out using vegetable and flower stalks waste to study the effectiveness of ligno-cellulolytic microorganisms (LCMs) obtained from the previous isolation on composting process, especially on enhancement of biodegradation rate of these organic materials. The addition of LCMs to compost showed promised to be a valuable asset by rendering timely benefits in efficiency, maturity, and quality of the composting. This was evidenced by a significant increase of temperature, O2 consumption and CO2 emission, and population density of LCMs in compost mass compared with that of biotic (addition of culture of horse feces) and abiotic (1% molasses amendment) treatments, as well as control trial. The phytotoxicity assay showed that the substrate became mature after 60 days’ composting. The LCMs inoculation enhanced the biodegradation of the composting materials as evidenced by an increasing screening ratio (1.2 cm sieve pore) of 34.5% in the treated trail, compared with that of control, which elucidated that big advantage of adding selected inoculants over other treatment, and screening ratio is a reasonable index to compare the quality of different compost. However, the inoculation seemed to have no significant effect on the moisture content, pH, and the final organic carbon of the composting materials. 相似文献
852.
《Disasters》2000,23(4):80-85
Books reviewed:
John Twigg and Mihir R. Bhatt, eds, Understanding Vulnerability
Joachim von Braun, Tesfaye Teklu and Patrick Webb, Famine in Africa: Causes, Responses, and Prevention
C. Emdad Haque, Hazrads in a Fickle Environment: Bangladesh
Walter Gillis Peacock, Betty Hearn Morrow and Hugh Gladwin, eds, Population and Food: Global Trends and Future Prospects
Roy Gutman and David Rieff, eds, Crimes of War: What the Public Should Know 相似文献
John Twigg and Mihir R. Bhatt, eds, Understanding Vulnerability
Joachim von Braun, Tesfaye Teklu and Patrick Webb, Famine in Africa: Causes, Responses, and Prevention
C. Emdad Haque, Hazrads in a Fickle Environment: Bangladesh
Walter Gillis Peacock, Betty Hearn Morrow and Hugh Gladwin, eds, Population and Food: Global Trends and Future Prospects
Roy Gutman and David Rieff, eds, Crimes of War: What the Public Should Know 相似文献
853.
Traditional high resolution mass spectrometry (HRMS) analysis for polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) can be time consuming and expensive. Consequently, alternative methods are of great interest to regulatory agencies and others characterizing contaminated sites. One factor that hinders acceptance of alternative methods is a lack of performance information that assesses the alternative method's impacts on analytical results. The U.S. Environmental Protection Agency's Superfund Innovative Technology Evaluation Monitoring and Measurement Technologies Program (EPA SITE MMT) encourages the development and implementation of innovative and alternative monitoring methods by providing performance information on site characterization technologies. This paper presents a comparison of the results obtained from laboratory-based alternative approaches for screening sediment and soil samples for dioxin toxicity equivalents (TEQ(D/F)) to results obtained using traditional HRMS. The laboratory-based approaches included modifying the traditional HRMS analysis to make it more cost-effective (alternate 1613B), analyzing extracts that had been prepared for HRMS using low resolution mass spectrometry, and determining total organic carbon (TOC) content as an indicator of PCDD/F content. These comparisons demonstrated that TEQ(D/F) values generated using toxicity equivalency factors proposed by the World Health Organization in 1998 applied to alternate 1613B and LRMS analyses have a strong linear correlation to the TEQ(D/F) values derived in the same fashion from traditional HRMS analysis. These results would have placed >90% of the samples within the same concentration intervals using ranges of <0.05, 0.05-0.50, 0.50-5, and >5ng TEQ/g. Natural log transformed data for TOC had significantly weaker correlation to TEQ(D/F), indicating that TOC is not a reliable indicator of TEQ(D/F) concentrations. 相似文献
854.
855.
内容依托教学是内容学习和语言学习为一体的教学方式,此种教学方法在高职商务英语专业教学中的应用效果卓著。通过观察和访谈收集相关数据,采用定性的研究范式,发现在内容依托教学的初步实施阶段还存在学生的认识态度、相关课程的教学内容以及测试和评估等方面的问题。 相似文献
856.
事故调查分析方法与技术述评 总被引:1,自引:0,他引:1
根据事故的原因结果模型、过程模型、能量模型、逻辑树模型、SHE管理模型将事故调查分析技术方法归纳为5大类,介绍了广泛使用的事故调查分析技术方法的特点,并按一定的标准进行分析和比较。分析表明:每种方法都有其不同的应用领域和优缺点,应针对不同领域问题选用合适的分析方法,多种调查技术组合分析适用于复杂事故的调查;考虑事件次序及其影响因素的调查方法,便于提出预防事故再次发生和减少风险的建议,图表阐述有利于鉴别信息缺陷,并使调查组之间的沟通有力;笔者在调查过程中注重于非正常分析方法得出的结果,宜采用更为先进的事故分析技术方法以保证事故调查的客观性。 相似文献
857.
Screening level risk assessment models are used by many countries to assess the treatability of organic chemicals during the sewage treatment process, especially those that are new to commerce. The performance of one such model, the sewage treatment plant model, is evaluated in the current study by comparing model predictions with actual measurement data collected at various stages of a typical full-scale activated sludge type sewage treatment plant. A suite of ten polycyclic aromatic hydrocarbons (PAHs) with widely varying physico–chemical properties were monitored for the comparison. Model predicted removal efficiencies were in very good agreement with those measured for all ten PAHs. Observed chemical concentrations and their trends at various stages of the sewage treatment process were also well simulated by the model. Results also suggest that a reasonable first approximation estimate of a range for the biodegradation half-life needed for the model may be obtained by dividing reported aqueous biodegradation half-life by scaling factors of 50 and 150. 相似文献
858.
欧洲大气颗粒物标准及监测体系 总被引:1,自引:1,他引:0
以欧洲环境空气质量及清洁空气指令为基础,从标准限值、监测点位布设、监测方法等多个方面,对欧洲大气颗粒物标准及监测体系进行了综合阐述。由极限值、目标值、暴露浓度限值、评价上限和下限等构成的标准限值体系协同作用,将欧洲大气颗粒物浓度控制在一定范围内;大气颗粒物监测点位布设方法遵循基本布设原则和最少点位数及AEI计算要求的详细规定;在颗粒物监测方法上,参比方法和等效方法并存,近年多种方法的应用情况也有所变化。通过对欧洲大气颗粒物标准及监测体系的综述,以期为中国大气颗粒物监测管理提供先进思路和技术参考。 相似文献
859.
In the last decades the European Union exerted influence on precautionary environmental planning by the establishment of several Directives. The most relevant were the Habitat-Directive, the EIA-Directive, the SEA-Directive and the Water Framework Directive. Comparing these EU policies in the area of environmental precaution it becomes obvious that there is a lot of common ground. Thus, the conclusion seems likely that the European Union, in doing so, has intended to establish general planning concepts through introducing several methodological steps indicated by the regulations. The goal of this article is firstly to point out, which are the common planning principles, converted by methodological elements and secondly examine the consideration of these planning concepts by the implementation and application in the member states. In this context it is analysed whether the connections and divergences between the directives lead to significant differences in the implementation process. To this aim the directives are shortly introduced and significant steps of the processes regulated by them are outlined. In the second steps the national legal implementation in the Alpine states and its consequences for the practical application are discussed. The results show a heterogeneous application of the EU principles. Within the comparative view on the four directives influence and causalities between the national implementation and the practical application were identified, which can be simplified as four types. Since a coherent strategic and methodological concept for improving environmental precaution planning from part of the EU is noticeable, more unity and comparability within the implementation is desirable, particularly in areas with comparable habitats such as the alpine space. Beyond this the trade-off between the directives poses an important task for the future. 相似文献
860.
We consider the management of urban stormwater in two connected dams. Stormwater generated by local rainfall flows into a
capture dam and is subsequently pumped into a similar sized holding dam. We assume random gross inflow and constant demand.
If we wish to minimise overflow from the system then the optimal management policy is to pump as much water as possible each
day from the capture dam to the holding dam without allowing the holding dam to overflow. We shall refer to this policy as
the pump-to-fill policy. The model is based on the Parafield stormwater management system in the City of Salisbury (CoS) but assumes constant
demand instead of level dependent outflow. If there is insufficient water in the holding dam to meet the desired daily demand
then all water in the holding dam is used and the shortfall is obtained from other sources. CoS, in suburban Adelaide in South
Australia, is recognised in local government circles as a world leader in urban stormwater management. The water is supplied
to local industry to replace regular mains water and is also used to restore and maintain urban wetlands. In mathematical
terms the pump-to-fill policy defines a Markov chain with a large transition matrix and a characteristic regular block structure.
We use specialised Matrix Analytic Methods to decompose the event space and find simplified equations for the steady state
probability vector. In this way we enable an elementary solution procedure which we illustrate by solving the modified Parafield
problem. The optimal nature of the pump-to-fill policy is established in a recent paper by Pearce et al. (JIMO 3(2):313–320,
2007). The purpose of the current study is to find optimal management policies for urban stormwater systems.
Work supported by the Australian Research Council. 相似文献