随着国际社会对保护海洋环境要求的不断提升,越来越多的港口和特定水域禁止船舶排放生活污水和灰水,这种禁排规定超出了国际海事组织(international maritime organization,IMO)的《国际防止船舶造成污染公约》(international conventio...随着国际社会对保护海洋环境要求的不断提升,越来越多的港口和特定水域禁止船舶排放生活污水和灰水,这种禁排规定超出了国际海事组织(international maritime organization,IMO)的《国际防止船舶造成污染公约》(international convention for the prevention of pollution from ships,MARPOL)中关于船舶生活污水和灰水的排放要求,使船舶不得不寻求其他舱室用于临时储存不允许排放的生活污水和灰水。该文针对目前船舶在营运过程中将生活污水和灰水临时储存在压载舱内的做法,分别通过对IMO压载水公约关于船舶压载水D-2标准排放要求,以及IMO MARPOL关于船舶生活污水和船舶灰水排放要求的解析,探讨了在压载舱内储存生活污水和灰水的可行性,同时结合IMO关于该问题的讨论进展,提出了在压载舱内临时储存灰水和经处理的生活污水需进一步考虑的技术和操作因素,以规避该行为可能带来的违规风险。展开更多
Damage to elevated water tanks in past earthquakes can be attributed to the poor performance of their supporting frame staging. In order to ascertain the performance of these elevated water tanks, it is crucial to cat...Damage to elevated water tanks in past earthquakes can be attributed to the poor performance of their supporting frame staging. In order to ascertain the performance of these elevated water tanks, it is crucial to categorize the damage in quantifiable damage states. Among various parameters to quantify the damage states, the top drift of frame staging can be conveniently correlated to the different damage levels. In literature, drift limits corresponding to different damage states of the frame staging of the elevated water tank are not available. In the present study, drift limits for RC frame staging in elevated water tanks corresponding to different seismic damage states have been proposed. Various damage states of the elevated water tank have been determined using the Park and Ang damage index. The Park and Ang damage index utilizes results of both pushover analysis and incremental dynamic analysis. Twelve models of elevated water tanks have been developed considering variation in staging height and tank capacity. Incremental dynamic analysis has been performed using the suite of twelve actual earthquake ground motions. Based on the regression analysis between damage indexes and drift, limiting drift values for each damage state are proposed.展开更多
采用两相流混合模型,选取RNG k-ε湍流模型封闭两相流时均方程,对辐流式二次沉淀池液固两相流力学特性进行三维数值模拟。采用有限体积法求解微分方程;紊动能、紊流耗散均采用Quick离散格式;速度与压力耦合求解时使用了压力隐式算子分裂...采用两相流混合模型,选取RNG k-ε湍流模型封闭两相流时均方程,对辐流式二次沉淀池液固两相流力学特性进行三维数值模拟。采用有限体积法求解微分方程;紊动能、紊流耗散均采用Quick离散格式;速度与压力耦合求解时使用了压力隐式算子分裂PISO(Pressure-Implicit with Splitting of Operators)算法。通过模拟获得了速度场、紊动能和污泥质量浓度等参量在空间的分布规律,对沉淀池的设计有一定的参考价值。展开更多
文摘随着国际社会对保护海洋环境要求的不断提升,越来越多的港口和特定水域禁止船舶排放生活污水和灰水,这种禁排规定超出了国际海事组织(international maritime organization,IMO)的《国际防止船舶造成污染公约》(international convention for the prevention of pollution from ships,MARPOL)中关于船舶生活污水和灰水的排放要求,使船舶不得不寻求其他舱室用于临时储存不允许排放的生活污水和灰水。该文针对目前船舶在营运过程中将生活污水和灰水临时储存在压载舱内的做法,分别通过对IMO压载水公约关于船舶压载水D-2标准排放要求,以及IMO MARPOL关于船舶生活污水和船舶灰水排放要求的解析,探讨了在压载舱内储存生活污水和灰水的可行性,同时结合IMO关于该问题的讨论进展,提出了在压载舱内临时储存灰水和经处理的生活污水需进一步考虑的技术和操作因素,以规避该行为可能带来的违规风险。
文摘Damage to elevated water tanks in past earthquakes can be attributed to the poor performance of their supporting frame staging. In order to ascertain the performance of these elevated water tanks, it is crucial to categorize the damage in quantifiable damage states. Among various parameters to quantify the damage states, the top drift of frame staging can be conveniently correlated to the different damage levels. In literature, drift limits corresponding to different damage states of the frame staging of the elevated water tank are not available. In the present study, drift limits for RC frame staging in elevated water tanks corresponding to different seismic damage states have been proposed. Various damage states of the elevated water tank have been determined using the Park and Ang damage index. The Park and Ang damage index utilizes results of both pushover analysis and incremental dynamic analysis. Twelve models of elevated water tanks have been developed considering variation in staging height and tank capacity. Incremental dynamic analysis has been performed using the suite of twelve actual earthquake ground motions. Based on the regression analysis between damage indexes and drift, limiting drift values for each damage state are proposed.
文摘采用两相流混合模型,选取RNG k-ε湍流模型封闭两相流时均方程,对辐流式二次沉淀池液固两相流力学特性进行三维数值模拟。采用有限体积法求解微分方程;紊动能、紊流耗散均采用Quick离散格式;速度与压力耦合求解时使用了压力隐式算子分裂PISO(Pressure-Implicit with Splitting of Operators)算法。通过模拟获得了速度场、紊动能和污泥质量浓度等参量在空间的分布规律,对沉淀池的设计有一定的参考价值。
基金Supported by the National Natural Science Foundation of China(Grant No.51179076)Natural Science Foundation of Jiangsu Province (No.BK2010042)“333 project” of Jiangsu Province (No.BRA2011180)
