Developing a CFD heat transfer model for applying high expansion foam in an LNG spill

Liquefied natural gas (LNG) is widely used to cost-effectively store and transport natural gas. However, a spill of LNG can create a vapor cloud, which can potentially cause fire and explosion. High expansion (HEX) foam is recommended by the NFPA 11 to mitigate the vapor hazard and control LNG pool fire. In this study, the parameters that affect HEX foam performance were examined using lab-scale testing of foam temperature profile and computational fluid dynamics (CFD) modeling of heat transfer in vapor channels. A heat transfer model using ANSYS Fluent® was developed to estimate the minimum HEX foam height that allows the vapors from LNG spillage to disperse rapidly. We also performed a sensitivity analysis on the effect of the vaporization rate, the diameter of the vapor channel, and the heat transfer coefficient on the required minimum height of the HEX foam. It can be observed that at least 1.2 m of HEX foam in height are needed to achieve risk mitigation in a typical situation. The simulation results can be used not only for understanding the heat transfer mechanisms when applying HEX foam but also for suggesting to the LNG facility operator how much HEX foam they need for effective risk mitigation under different conditions.     

建立“环境和谐度指数”探讨

本项目以大众密切关注的城市小区或拟开发小区为对象,从研究空气、水体、噪声、固体废弃物和土壤等重要环境要素与人体健康和人居环境质量关系出发,提出并阐明“环境和谐度指数”的概念,量化重要环境要素在环境和谐度指数评价体系中的贡献,目的在于为评估城市小区或拟开发地块的环境和谐度提供有益探索,促进人居环境和谐自然的协调持续发展。     

产业转移视角下京津冀石化产业碳排放因素分解与减排潜力分析

石化产业是我国经济的支柱性产业,但其大量的碳排放却给环境造成严重负担,因此提倡石化产业低碳发展能有效推动京津冀区域经济与环境绿色均衡发展.基于产业转移视角,分析2007-2016年京津冀区域石化产业碳排放量现状;运用对数平均迪式分解（Logarithmic Mean Divisia Index,LMDI）法分解并分析京津冀区域石化产业碳排放量影响因素在三地的作用效果,进而借助产业竞争力系数佐证碳排放量影响因素作用效果在区域间的关联性;最后通过合理调整京津冀区域石化产业能源结构,将未调整和调整后的能源结构类型分别设置为基准情境和低碳情境,利用SPSS拟合最优曲线来预测2017-2030年京津冀区域石化产业减排潜力.结果表明:①2007-2016年京津冀区域石化产业碳排放量增加386.79×104 t,碳排放强度由0.77 t/（104元）降至0.31 t/（104元）.②2007-2016年,能源强度因素使京津冀区域石化产业碳排放量减少13 663.77×104 t,其贡献率高达148.38%;人均GDP因素促使石化产业碳排放量增加12 327.10×104 t,贡献率达110.69%.③对于石化产业竞争力系数,北京市由0.03降至-0.02,为三地石化产业转出地;河北省由-0.14增至0.16,为转入地.④在低碳情境下,2020年、2030年京津冀区域石化产业碳排放量分别比基准情境减少502.84×104、528.95×104 t,碳排放强度分别降至0.19、0.17 t/（104元）,均达到发展目标的要求.研究显示,2007-2016年京津冀区域石化产业碳排放量逐年上升,承受巨大减排压力,该区域可以通过调整石化产业能源结构来挖掘碳减排潜力,推动石化产业绿色发展.      

频域子结构方法在力学环境预示中的应用研究

目的利用频域子结构方法(FBSM,FRF Based Sub-structuring Method)对结构的力学环境进行准确高效地预示。方法分别对处理子结构间为刚性连接和弹性连接两种问题的FBSM进行理论推导。为了验证FBSM的正确性,设计连接为刚性连接和弹性连接两种算例结构,并将FBSM对算例结构频响函数的计算结果与有限元方法(FEM,Finite Element Method)的对应计算结果进行对比。其中,弹性连接利用空间梁单元进行等效,并将该等效方法与利用六自由度标量弹簧的等效方法进行对比。结果对于刚性连接和弹性连接两种情况,FBSM对频响函数的计算结果均与FEM的对应计算结果吻合程度良好。此外,空间梁单元的结点刚度矩阵为非对角阵,与六自由度标量弹簧相比,可更为准确地等效工程实际中的弹性连接。结论FBSM可对结构的力学环境进行准确高效的预示,且在处理具有弹性连接结构的力学环境预示问题时,可采用空间梁单元等效弹性连接。     

陕西耀县县城建筑物震害预测

对房屋建筑震害预测的“评分法”作了一些改进,并根据陕西耀县县城建筑物的特点,对群体建筑物、重要建筑物和古建筑物分别采取不同的方法进行震害预测,得出了合理的结论,本文的工作方法对其它小城镇的震害预测有一定的参考意义．     

Testing Accuracy of Finite Element and Random Walk Schemes in Prediction of Pollutant Dispersion in Coastal Waters

Distribution of pollutants in coastal waters is usually represented by depth averaged twodimensional convection-dispersion equation. Under very specific conditions this equation can be solved analytically. Although such a solution is restricted to simplified situations it provides a very useful case for testing the performance of various numerical solution techniques currently available for the simulation of convective-dispersion of pollutants in natural water systems. In this paper the analytical solution of the convective dispersion equation is used as a benchmark against which the accuracy of other techniques are assessed. These assessments are based on quantitative comparisons between the results of the solution of two-dimensional convection-dispersion equation by the deterministic finite element and stochastic random walk methods. Both Eulerian and Lagrangian frameworks are employed to obtain the finite element solution of the convection-dispersion problem. It has been shown that the Lagrange–Galerkin finite element scheme yields the most accurate results for the case under study. However, computational costs of the Lagrange–Galerkin method can be relatively high and under certain conditions it may be reasonable to use a less accurate but cost effective random walk scheme to make water quality management decisions.     

气浮法处理钢纸生产废水

钢纸生产废水是含锌的酸性废水．牡丹江市是生产钢纸城市之一。这方面的研究工作多年来一直未开展，含锌酸性废水的污染问题也一直未得到解决．采用气浮法处理该废水，取得了良好的经济和环境效益     

水生态毒理学中检测慢性毒性的短期试验方法

本文主要介绍了国外水生态毒理学研究和水质量管理中广泛应用的四种检测慢性毒性的短期试验方法．综述了其方法研究和应用的情况．这几种方法是鱼类和两栖类胚胎－幼体存活和致畸试验，黑头软口鲦幼体７天生长存活试验，网纹蚤７天存活繁殖试验和大型蚤慢性毒性的短期试验方法．文中还对研究和发展适合我国情况的检测慢性毒性的短期试验方法提出了建议．     

高等师范院校环境教育的探讨

从分析高等师范院开展环境教育的历史背景出发，提出了开展环境教育的主要途径及方法。     

活性污泥二次污染问题的探讨

讨论了城市污水经过A／O工艺处理时活性污泥的二次污染问题。所采用的方法是将原水、处理后的出水及活性污泥用乙酸丁酯萃取、萃取相经过真空浓缩后，采用GC／MS测定了样品中的有机化合物。结果表明，在A／O工艺处理城市污水过程中，活性污泥的吸附作用是主要的，降解作用是次要的：A／O工艺所排放的活性污泥仍然是一种危险的污染物。