A new approach for process intensification through process simplification is proposed. This approach is based on a mass-integration framework for reducing the number of processing steps for grassroots and retrofit designs. Two procedures are presented based on graphical and mathematical programming techniques. The process simplification task is aimed at synthesizing process configurations that involve the least number of processing steps while yielding a certain product from a set of raw materials. The new concepts of maximum extendible zones and product paths are introduced and incorporated into the design procedure. The solution identifies the simplest processes along with their configuration, stream distribution, and basic performance data.
In India, large-scale canal irrigation schemes have been in operation for more than a century. At present, there are 1248 major and medium irrigation schemes in the country. During the past three decades there has been a dramatic increase in the use of groundwater for irrigation. As a result, India has the world's largest gross irrigated area (77 million ha). The irrigation development has been widely acknowledged to have helped the country not only to achieve food self-sufficiency but also to be an exporter of agricultural produce in recent times. However, it is now realized that drainage is one of the areas that has not been given an adequate and equal status, while planning for water resource development coupled with a programme for a rapid expansion of irrigation infrastructure, during the era of the ''green revolution''. Drainage provision was generally deferred or postponed in many cases due to the paucity of funds in the initial stages and thus was left to be taken up subsequently or as a curative measure to address waterlogging and salinity problems as encountered. Copyright # 2007 John Wiley & Sons, Ltd.key words: waterlogging; salinity; command area; subsurface drainage; bio-drainage; socio-economic constraints RÉ SUMÉEn Inde, les grands périmètres d'irrigation par canaux fonctionnent depuis plus d'un siècle. Il y en a actuellement 1248, grands et moyens, dans le pays. Au cours des 30 dernières années il y a eu une très forte augmentation de l'utilisation des eaux souterraines pour l'irrigation. En conséquence, l'Inde possède le plus vaste secteur irrigué du monde (77 millions ha). Il est couramment admis que c'est grâce au développement de l'irrigation que le pays a pu non seulement atteindre l'auto-suffisance alimentaire mais aussi devenir récemment exportateur de produits agricoles. Cependant, le drainage apparaît aujourd'hui comme un des secteurs les moins bien traités dans ce contexte de développement des ressources en eau associé à une expansion rapide des infrastructures d'irrigation, autrement dit pendant la « révolution verte ». La pratique du drainage a été généralement reportée ou, dans de nombreux cas, remise à plus tard, par manque de fonds dans les étapes initiales, et est donc devenue un accompagnement ultérieur ou une mesure curative pour traiter les problèmes d'engorgement et de salinité lorsqu'ils se posent.
This paper proposes a triple output converter with buck, boost and inverted outputs and controlled through duty cycle estimation. In the existing converter, to generate the negative output, the power flows from load to the supply (from the boost output to the supply) during a part of the cycle, which increases cycle time and losses, and reduces the power level. To overcome this, a modified converter with a main and an auxiliary inductance and with reduced number of switches is proposed. The converter can operate in continuous and discontinuous conduction modes and the outputs can be independently controlled. An analysis of the converter is done for both modes. A simplified control of the converter through duty cycle estimation is suggested to regulate the outputs, which does not have the constraint that the current ripple has to be small. The control works both in the continuous and discontinuous modes. The simulation results closely match with the analysis. A prototype of the converter is constructed with a Spartan FPGA system and results have been presented.
A Basin-wide Holistic Integrated Water Assessment (BHIWA) model was developed by the International Commission on Irrigation and Drainage (ICID) under the Country Policy Support Programme (CPSP) to study and integrate impacts of water for ''food'', ''people'' and ''nature'' sectors on water availability and derive policies supporting sustainable development. The model was applied to two typical river basins in India. The model provides for past, present and future conditions a sound and much broader ''knowledge base'' to understand the state of water availability under alternative scenarios by different use sectors at the basin/sub-basin level. The scenario-based approach has allowed the testing of various plausible policy options for managing water and related land resources and to suggest suitable modifications in India's National Water Policy.
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