Formulating an ecosystem approach to environmental protection

The U.S. Environmental Protection Agency (EPA) has embraced a new strategy of environmental protection that is place-driven rather than program-driven. This new approach focuses on the protection of entire ecosystems. To develop an effective strategy of ecosystem protection, however, EPA will need to: (1) determine how to define and delineate ecosystems and (2) categorize threats to individual ecosystems and priority rank ecosystems at risk. Current definitions of ecosystem in use at EPA are inadequate for meaningful use in a management or regulatory context. A landscape-based definition that describes an ecosystem as a volumetric unit delineated by climatic and landscape features is suggested. Following this definition, ecosystems are organized hierarchically, from megaecosystems, which exist on a continental scale (e.g., Great Lakes), to small local ecosystems.Threats to ecosystems can generally be categorized as: (1) ecosystem degradation (occurs mainly through pollution) (2) ecosystem alteration (physical changes such as water diversion), and (3) ecosystem removal (e.g., conversion of wetlands or forest to urban or agricultural lands). Level of threat (i.e., how imminent), and distance from desired future condition are also important in evaluating threats to ecosystems. Category of threat, level of threat, and distance from desired future condition can be combined into a three-dimensional ranking system for ecosystems at risk. The purpose of the proposed ranking system is to suggest a preliminary framework for agencies such as EPA to prioritize responses to ecosystems at risk.     

聚合硫酸铁中碱化度的分析方法

本文着重介绍了聚合硫酸铁中碱化度的分析方法，其方法可靠、准确，对聚合铁的质量分析及生产指导均有较大帮助。     

参与式方法在乡村生态恢复与保护规划中的应用

对区域生态环境恢复与保护的规划,传统上由相关技术人员应用生态经济学原理和景观生态学的方法进行。把当前国际发展领域通用的参与式方法与生态规划方法相结合,通过多层次、多学科、多部门的共同参与,使外来者的技术和当地相关利益群体的经验比较好地融合,完成村民参与式的生态环境恢复与保护规划。利用这种方法形成的规划,能够增强社区村民的拥有感,有利于规划付诸实施。     

一个液相化学反应机理的建立和应用

利用比较积分反应速率的方法，建立了一个简化液相化学反应机理ＡＲＣＭＬ，并在各种大气状况下以及各种物理参数下对ＡＲＣＭＬ作了验证，然后利用ＡＲＣＭＬ模拟光化学烟雾形成初期的云水酸化过程，结果表明，自由基氧化Ｓ（Ⅳ）在污染或高ＮＯｘ的大气中非常重要。     

Euclid贴近度-灰色关联模型在环境评价中的应用

在结合实例进行分析的基础上,指出了传统的灰色平均关联度可能出现的关联度和实际的贴近程度不一致的缺陷。通过引入欧几里德贴近度,建立欧几里德贴近度-灰色关联复合模型,解决了灰色平均关联度的这一不足,并结合石家庄市地表水环境质量评价说明该模型的应用,得到了与实际情况一致的评价结论,表明这一模型是合理和可行的。     

Experimental study on unconfined methane explosion: Explosion characteristics and overpressure prediction method

Explosion accidents have become the main threat for the high-efficiency use of cleaner gas energy sources, such as natural gas. During an explosion, obstacle causing flame acceleration is the main reason for the increase of the explosion overpressure, which still remains to be fully understood. In this research, field experiments were conducted in a 1 m³ cubic frame apparatus to investigate the effect of built-in obstacles on unconfined methane explosion. Cage-like obstacles were constructed using square steel rods with different cross section size. The results demonstrated that the flame could get accelerated due to the hydrodynamic instability and obstacle-induced turbulence, which enhanced the explosion overpressure. In the near field, the overpressure wave travelled slower and the maximum overpressure could almost keep constant. Reducing the cross section size, or increasing the obstacle height or the obstacle number per layer could determine the rise of the maximum overpressure, the maximum pressure rising rate and the overpressure impulse. For uniformly constructed obstacles, self-similar theory was chosen to measure the influence of the hydrodynamic instability, and a parameter β was adopted to measure the flame acceleration caused by obstacle-induced turbulence, the value of which was 2 in this research. Based on the acoustic theory, an overpressure prediction model was proposed and the predicted results agreed with the measured values better than previous models, such as TNT equivalency model and TNO multi-energy model.     

Risk-based quantitative method for determining blast-resistant and defense loads of petrochemical buildings

Petrochemical buildings are usually distributed near chemical installations and have a high risk of explosion because of the concentration of people. In order to effectively design and protect buildings against explosion, it is needed to determine the blast-resistant and defense loads reasonably. Based on the theory of risk, a triangular pyramid explosion risk model was established in this study, which combined the overpressure p, duration t, and frequency f of the explosion scene at the same time. The first principle of “acceptable cumulative frequency” and the key principle of “maximum explosion risk” were formulated. According to this method, the explosion risk of eight leakage units with 10 groups of leakage hole size and three dangerous wind directions were obtained. According to the cumulative explosion frequency curve and the explosion risk curve, blast-resistant and defense loads of the four walls were determined quantitatively. Among the four walls, the explosion overpressure were 44.0–74.5 kPa, and the corresponding duration were 34.1–39.1 ms. The cumulative explosion frequency were 2.11E−5 to 8.58E−5 times annually. The explosion risk value were 3.64E−3 to 5.35E−3 kPa·ms annually. The results indicated that it was of great importance for the calculation of the explosion risk to reasonably divide the leakage unit and determine the leakage frequency. The explosion scene and its frequency, the volume of the obstructed region, and the distance of the explosion source were the key variables that affected the explosive load. The final blast-resistant and defense load values were found in the case of the middle hole size leakage. Blast-resistant and defense loads not only met the risk acceptance standard but also considered the overpressure and the duration of explosion. At present, they have been extensively applied in the blast-resistant design and engineering transformation of buildings in SINOPEC.     

环境执法工作面临的问题与改善途径

阐述环境执法存在的问题,对其现状、原因及进一步完善环境执法、提高依法行政水平提出了设想和建议。     

A cluster-based decision support system for estimating earthquake damage and casualties

This paper describes a Decision Support System for Disaster Management (DSS-DM) to aid operational and strategic planning and policy-making for disaster mitigation and preparedness in a less-developed infrastructural context. Such contexts require a more flexible and robust system for fast prediction of damage and losses. The proposed system is specifically designed for earthquake scenarios, estimating the extent of human losses and injuries, as well as the need for temporary shelters. The DSS-DM uses a scenario approach to calculate the aforementioned parameters at the district and sub-district level at different earthquake intensities. The following system modules have been created: clusters (buildings) with respect to use; buildings with respect to construction typology; and estimations of damage to clusters, human losses and injuries, and the need for shelters. The paper not only examines the components of the DSS-DM, but also looks at its application in Besiktas municipality in the city of Istanbul, Turkey.