The dissolution of a stationary bubble enhanced by chemical reaction

The problem of the dissolution of a gas bubble aided by a first order chemical reaction is treated theoretically. Two new approximate solutions are developed. The first one is based on a time-expansion introduced by us recently, is useful for small values of the reaction rate parameter. The second utilizes the assumption of a thin boundary layer, and is applicable for relatively large values of the reaction rate parameter. The accuracy of these and other approximations is assessed by comparison with a numerical solution of the complete model equations.     

Film models for multicomponent mass transfer; computational methods: the exact solution of the maxwell-stefan equations

Computational difficulties which have been encountered in using the Krishna—Standart method for calculation of interphase mass transfer rates in multicomponent mixtures are discussed. Consideration is given to various alternative methods of performing the matrix calculations involved and to the stability of such methods. On this basis a computer algorithm is developed which is faster and more reliable than that published previously.     

从波茨坦广场看德国现代建筑发展

在波茨坦广场众多的建筑中,新国家美术馆、柏林爱乐音乐厅和索尼中心犹如三颗耀眼的明星,它们的存在记录着德国现代主义建筑的发展过程。当这三栋建筑同时屹立在波茨坦广场的时候,仿佛可以看到,历经一个多世纪的现代主义建筑风格经过演变和发展依然具有旺盛的生命力。     

批判性重建——德国柏林波茨坦广场的空间形态分析

文章首先简述了波茨坦广场的空间形态的历史演变过程,然后具体介绍东西柏林统一后广场的重建工作,围绕着柏林市政府"批判性重建"理念分区块对波茨坦广场进行空间结构的评述,期从而对"批判性重建"理念产生批判性的认识。     

Interacting limits to algal growth: Light, phosphorus, and carbon dioxide availability

Most studies of limiting factors to algal growth seek to quantify the effect of individual factors. However, rates and amounts of photosynthetic carbon fixation in laboratory cultures of Anacystis nidulans show simultaneous dependence on the availability of phosphorus, carbon dioxide, and light. Thus, not all limiting factors may act independently to control algal growth in aquatic systems, and further research into the extent of such interactions is needed.     

A new interpretation for formation of orthogonal joints in quartz sandstone

Two vertical and orthogonal systematic joint sets are generally arrayed in a grid pattern on the bedding surface,which are the significant features of flat-lying sandstone terrains.Although extensive researches are reported on this topic,many fundamental problems have still not been solved.Such mutually perpendicular opening-mode fractures are an obvious manifestation of effective tensile stresses in two orthogonal directions in the horizontal bedding plane.A good understanding of these orthogonal joint systems is a key to structural analysis,landscape interpretation,and guidance of resolving a number of very practical problems in engineering,mining and hydrologic projects.Based on an anatomic investigation on the orthogonal joints in the Potsdam sandstone of Cambrian age at Ausable Chasm(New York State,USA)and Beauharnois(Quebec,Canada),we proposed that the orthogonal joints may result from the auxetic effects of quartz-rich sandstone rather than local or regional rotation of the maximum tensile stress(σ₃)direction by about 90°.The sandstone beds with negative Poisson's ratios are so fascinating that,when placed under vertical burial compression and layer-parallel extension in one direction(σ₃),it becomes stretched in the transverse direction(σ₂),producing two orthogonal sets of mutual abutting and intersecting joints(J1 and J2 normal toσ₃ andσ₂,respectively),and both are normal to the bedding surface.Joint set J1 is more closely-spaced than J2 by a factor of～3.3,which is correlated with an average Poisson's ratio of?0.3 for the Potsdam sandstone at the time of joint formation.     

‘Activating Nature’: The Magic Realism of Contemporary Landscape Architecture in Europe

The redefinition of European cities has created new opportunities for the greening of public urban spaces. Lucy Bullivant describes how three young practices in particular – West 8, Gross.Max and Mosbach Paysagistes – are leading the way with their highly dynamic and inventive narrative approaches to history, culture and the emergent city. Copyright © 2007 John Wiley & Sons, Ltd.