Study of a membrane bioreactor with glass fiber flat grille modules and the modules' optimization based on the local critical flux theory

A novel flat grille membrane module using inorganic glass fibers as filter media is proposed for use in a membrane bioreactor for wastewater treatment. A model which integrates the concepts of back transport velocity, spatial local critical flux and temporal variation of the local flux has been developed. The membrane module was optimized based on experimental results and calculations using the model. The optimized parameters include the volume ratio of membrane solution for the surface modification of glass fibers, the fiber inner diameter and fiber length. The optimal values were 1:2 and 5 mm respectively but the length had little effect on the performance of the module. The critical time was then calculated with the model and an equation developed. The result was in very good agreement with the observed one. Finally, the performance of the glass fiber MBR was monitored. The effluent quality and stability of the system were comparable to that of conventional MBRs. This MBR will be a promising technique for wastewater treatment given its low cost, high strength and good effluent quality.     

影响我国房地产价格变化因素分析

近年来．我国房地产价格持续上涨。为了平抑房价。国家采取了调控措施．房地产价格上涨速度虽然减缓．但价格仍居高位。文章从宏观调控下我国房地产投资的特点出发。通过对影响我周房地产价格变化因素进行分析，力图探明住房价格持续上涨问题的根源，并提出相应的政策建议。     

节能住宅推广动力分析

节能住宅推广过程中,开发商作为政策执行者也是最直接的推动者,扮演着发动机的角色,而这台发动机的燃料则来自于政府和消费者,三者共同构成了节能住宅推广的动力系统.政府恰当的政策措施和开发商的营销策略将使这一系统动力倍增.     

承载乡土基因的旅游生态聚落空间——以云南丘北县普者黑镇彝族旅游小镇规划为例

"青绿山水,重彩彝居"的特色资源使云南丘北县普者黑彝族小镇的旅游开发获得了经济效益,但旅游业的发展也带来了传统聚落风貌受到严重损害等不良后果.规划以"乡土意"为理念,对当地彝居原型进行分析、提炼,对材料工艺进行改造,预设多种"新型彝居"和公共服务设施的营构方式,以正确引导民居改建;规划还将山体作为空间轴线的重要组成部分,将水体引入小镇,并对水岸进行柔化处理,使聚落因水而建.     

The impact of urban street layout on local atmospheric environment

The investigation was carried out to reveal the impact of urban street layout on local atmospheric environment through computational fluid dynamics (CFD) numerical simulations using standard k$k$–ε$\epsilon$ turbulence model. Different street canyon configurations are considered and the flow regimes summarized according to the aspect ratio of the leeward building height and the street width H1/W$H1/W$ and the aspect ratio of the leeward building height and the windward building height H1/H2$H1/H2$. Three regimes are defined to denote the vortices and characteristics of pollutant dispersion in street canyons according to the parameters H1/W$H1/W$ and H1/H2$H1/H2$. It is found that the pollutant transport and diffusion is strongly dependent upon the type of flow regime inside the canyon and exchange between canyon and the above roof air. The study indicated that there is a strong influence of the street layout on the wind field and the pollutant dispersion in the street canyon mainly depends on the vortex structure in the canyon. The results are validated against an extensive wind tunnel experimental (Meroney and Rafailidis) [Journal of Wind Engineering and Industrial Aerodynamics, 1996;62:37–56; http://www.mi.uni-hamburg.de] and the simulated results concluded by Sini [Atmospheric Environment 1996;30:2659–77] and Sang [Atmospheric Environment 2002;36:1137–45].     

博弈论视角下的 PPP 模式政府监管研究

PPP 模式在我国公共服务领域的应用日益广泛,越来越多的问题也随之暴露,其中较为突出的是政府监管问题。政府和私人部门的合作,本质上是二者之间博弈的结果。本文以博弈论的视角分别从宏观和微观两个层面利用 4 种博弈模型来分析 PPP 模式下私人部门与政府之间的博弈过程,发现政府监管问题的关键在于促进私人部门积极履约。由此结合我国 PPP模式下政府监管的不足给出如何加强政府监管的合理建议,旨在促进 PPP 模式在我国的发展     

呼和浩特将军衙署保护之思考

对呼和浩特将军衙署的周边环境现状进行了分析,并对其成因和保护对策进行了思考,提出了一些相应的保护措施,以提升城市的文化品味,彰显城市景观特色,最终促进旅游业的发展。     

当代建筑结构体系中的技术表现分析

建筑技术的发展一直伴随着建筑艺术的发展,当代建筑结构技术也成为了建筑表现的重要因素之一,其在满足建筑形式和功能要求的同时,开始更多地关注哲学思想、人文情感和环境意识的表达.该文分析和总结了当代建筑结构技术在建筑表现中的运用和发展趋势,希望这样的分析与归纳对建筑实践有一定的参考意义.     

代建制在政府投资项目中的应用研究

我国近年已出台一系列政策法规,支持在政府投资项目中推行代建制,并在各地因地制宜进行了许多有益尝试,但同时也暴露出政策、技术等方面存在的问题,本文主要针对推行中出现的问题进行分析和研究。     

政府委托人与代建人的风险分配研究

基于项目全寿命周期风险分析原则,研究代建制中政府委托人、代建人在项目决策阶段、实施阶段(设计、施工阶段)、使用阶段的风险承担问题,提出了政府委托人与代建人的风险分配原则,并依据该风险分配原则得到了政府委托人与代建人的风险分配结果。