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Abstract: India, which is in the mid latitude region, has extremly hot summers on its plains. In Northern and Central region of the country the maximum day temperature often goes beyond 45°C. The temperature inside the buildings, which generally have horizontal RCC roof, is unbearable without air conditioning. The steep rise in the cost of electricity has driven architects and builders to use passive cooling techniques in the construction. In this paper we examine the present methods that use an insulation layer to reduce the heat flux entering the living space bringing out their merits and demerits. Further we present an innovative approach in roof design that incorporates a layer of fly ash pieces which works as a porous insulation layer. The method has been implemented in a residential building in Delhi (28.380N). The experimental results demonstrate that the layer provides excellent insulation and it also shows structural stability. [Copyright &y& Elsevier]

Abstract: This paper is devoted to the comparative study of the radon flux vs. uranium content and radon flux vs. porosity for mineral samples from some typical Indian rocks (schists, quartzites, argillaceous quartzites, slates and granites) used as building materials, primarily around the Singhbhum Shear Zone, Jharkhand State. As the radon flux of any particular rock type was investigated with reference to its uranium activity and porosity, a good concordance of porosity on radon flux was observed. Such a significant influence of porosity on radon flux was also observed when different rock types were inter-compared. For example, granite that is commonly considered as typical source of indoor radon showed depleted level of radon flux when compared to most other rocks in the study area. In case of rocks such as slates and argillaceous quartzites, low porosity exhibited reduced radon flux in spite of their enhanced radioactive source content. It is concluded that it may not be advisable to utilize materials that are uranium depleted for construction purposes without giving importance to the materials'' porosity. [Copyright &y& Elsevier]

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Use of the Soil Conservation Service curve number (SCS-CN) approach is very popular among hydrologists. Despite this, its applications in water quality modeling have been very limited. For the first time, the present work explores the potential of the SCS-CN approach in water quality modeling of the river bank filtration process using a theoretical framework. The approach relates the curve number (CN) with the filtration/kinetic coefficient and the input applied to the system. The approach is tested for its effectiveness using the field data collected at the river bank filtration site at Haridwar, India. The CN is found to be dependent on travel time between source water and the abstraction well in addition to the influent concentration. For very low or very high values of influent concentration, the curve number exhibits an asymptotic variation approaching 100 and 0, respectively. Using the data on source water quality and the travel time, it is possible to compute the curve number and, subsequently, the filtrate quality at an abstraction well. [ABSTRACT FROM AUTHOR]