The effect of vent ducts on the reduced explosion pressures of vented dust explosions

An investigation into the effects of vent ducts on reduced explosion pressures is described. Experiments were made using an 18.5m³ explosion vessel and a modified 20 1 sphere, with dusts having K_st values ranging from 144 bar ms⁻¹ to 630 bar ms⁻¹. The vent area/vessel volume ratio bursting pressure of the vent cover, and the length to diameter ratio of the vent duct have been varied. Straight vent ducts, and ducts containing sharp 45° and 90° bends have been used.A simple model to describe the effect of vent ducts on the reduced explosion pressure has been derived and compared with the experimental results. Agreement is shown to be satisfactory in nearly all cases. A comparison between the experimental results and guidance on the effect of vent ducts already available in the literature is discussed.     

Complementarity between mitigation and adaptation: the water sector

The water cycle, a fundamental component of climate, is likely to be altered in important ways by climate change. Climate change will most likely worsen the already existing water related problems. Then the question is how should policy makers respond to this dilemma. Climate change mitigation, through greenhouse gas (GHG) emissions reduction and sequestration is not a sufficient response. Adaptation will also need to feature as a response strategy. Mitigation and adaptation need to be viewed as complementary responses to climate change. Complementarity between adaptation and mitigation in the water sector will be addressed in this paper. The paper will also outline the main impacts of climate change on water resources and identify those areas that are most dependent and vulnerable to hydrological systems (e.g., hydroelectric systems, irrigation, agriculture) and any changes thereof resulting from climate change. It will aim to assess the impact of water demand and water use, with a view to identifying the main relationships between mitigation and adaptation in the water sector and the means through which individual mitigation and adaptation actions can potentially interact with each other for the benefit of the water sector as a whole. It will also explore the implications of climate change on the management of water resources. Adaptation and mitigation options would be considered in the context of their socio-economic and environmental impacts and their contribution to sustainable development. A brief evaluation of how this information can be directly used for planning purpose will also be presented.

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沈阳北部污水处理厂出水回用于丁香湖溶质运移预测

通过对北部污水处理厂出水、丁香湖地区水环境质量现状评价,采用Visual MODFLOW数值模拟方法预测北部污水处理厂出水再生回用于丁香湖后研究区水质的变化情况,分析由此可能带来的水环境水质风险,来研究北部污水处理厂出水再生利用于丁香湖方案在水质上的可行性。预测结果显示：在地下水动力场作用下,随着时间的延长,SO4^2-将向下游不断运移并出现了累积现象,污水再生利用到丁香湖后,对地下水环境未来情况有一定的影响。     

Assessment of Wastewater Reuse Effects on Nutrient Loads from Paddy Field Using Field-Scale Water Quality Model

CREAMS-PADDY, a modified version of the field-scale CREAMS model, simulates the hydrologic, sediment, and nutrient cycles in paddy fields. The CREAMS-PADDY model was applied to estimate the effects of using wastewater for irrigation on nutrient loads from paddy fields in Republic of Korea. The model was calibrated and validated using data from two rice paddy fields. The coefficient of determination between observed and simulated total nitrogen and total phosphorus were 0.92 and 0.57, respectively, for the calibration period and 0.84 and 0.73 for the validation period. Simulations showed that when using wastewater for irrigation, the total nitrogen loads increased by 210% and total phosphorus by 1,270% when compared with conventional water irrigation. The total nitrogen and total phosphorus concentration in the ponded water increased by 254 and 534%, respectively, when compared with conventional water irrigation. The effect of reducing N and P fertilizer application rates by 10, 30, and 50% on nutrient loads exiting a paddy field were also simulated using the validated CREAMS-PADDY model. These simulations indicated that total phosphorus loads from the paddy were reduced only slightly by reducing the fertilizer, while total nitrogen loads were reduced by as much as 8.8, 16.6, and 24.4% when N ferlitizer rates were reduced by 10, 30, and 50%, respectively. An erratum to this article can be found at