MODLEACH: A Variant of LEACH for WSNs

Wireless sensor networks are appearing as an emerging need for mankind. Though, Such networks are still in research phase however, they have high potential to be applied in almost every field of life. Lots of research is done and a lot more is awaiting to be standardized. In this work, cluster based routing in wireless sensor networks is studied precisely. Further, we modify one of the most prominent wireless sensor network's routing protocol "LEACH" as modified LEACH (MODLEACH) by introducing \emph{efficient cluster head replacement scheme} and \emph{dual transmitting power levels}. Our modified LEACH, in comparison with LEACH out performs it using metrics of cluster head formation, through put and network life. Afterwards, hard and soft thresholds are implemented on modified LEACH (MODLEACH) that boast the performance even more. Finally a brief performance analysis of LEACH, Modified LEACH (MODLEACH), MODLEACH with hard threshold (MODLEACHHT) and MODLEACH with soft threshold (MODLEACHST) is undertaken considering metrics of throughput, network life and cluster head replacements.Comment: IEEE 8th International Conference on Broadband and Wireless Computing, Communication and Applications (BWCCA'13), Compiegne, Franc

Effects of radiation on the leach rates of vitrified radioactive waste

This report reviews the possible effects of both radiation damage to the glass and of radiolysis of the leachant on the leaching behaviour of vitrified radioactive waste. It has been stimulated particularly by recent papers, which have suggested that the leach rates of glasses will be enhanced by large factors after a ‘critical’ dose of radiation from alpha decays. These experiments have been conducted at highly accelerated rates using ion beams. The relationship between these experiments and the situation in vitrified waste has been assessed, taking into account the fact that experiments using alpha emitters incorporated in the glass have failed to find significantly enhanced leach rates after doses about five times larger than those equivalent to this ‘critical’ dose. It is concluded that these differences are observed partly because the ion beam experiments are carried out at such high dose rates that some recovery effects important at lower rates do not come into play. In the case of experiments with 2 keV argon ions, surface effects other than genuine radiation damage must be taken into account. In practice, if water has penetrated the canister, vitrified waste will be irradiated in the presence of the leaching solution. Enhancements of the leach rate due to the transient effects of radiation in the solid are shown to be completely negligible. The effects of radiolysis of the leaching solution and of any air in contact with the solution have also been considered in some detail and related to recent experiments by McVay and Pederson. It is shown that these radiolysis effects will not lead to any situations requiring special precautions in practice, although changes in surface leach rate by small factors can be expected under some circumstances. Any effect of irradiation on leach rates must be seen in the context of a waste repository. Along with other studies we hold the view that the rate of loss of material will be limited by the access of water to the repository, and will therefore depend on the effective saturation solubility of the glass in the leachant, not on the leach rate as usually determined in laboratory tests. Radiation damage is not expected to change the saturation solubility by more than a factor of two or three

Bernard Leach: graphic artist

Bernard Leach was one of the first, great, donors to the emerging Crafts Study Centre. He donated a substantial body of his own ceramics, including rare early pieces; he also gifted his personal study collection of Oriental ceramics and early English pottery (inspirational pots 'that gave me joy'). His archive of prolific writings, diaries, photographs and extensive correspondence is an unrivalled source for research and study and is called on by scholars internationally. More recently, gifts have been made of new personal papers as well as the etching plates that Leach worked on between 1907-8 as a student and then in Japan until 1920. These etching plates remind us that Leach began his career intending to be a fine artist. Whilst he produced etchings in Japan during his first creative steps, he remained committed to drawing throughout his life and his skill as a painter of pots remains one of his distinguishing attributes. This new exhibition brings together archives. etchings and drawings together with his early ceramics to present a rounded portrait of an eminent artist discovering a life-long interest in and aptitude for ceramics, set in the context of his first love of drawing. The exhibition has been curated by Jean Vacher, Collections Manager of the Crafts Study Centre. Many of these etchings have rarely been seen in the museum environment, and the project, generously supported by the Daiwa Anglo-Japanese Foundation, is intended to stimulate a wider understanding of Leach's output as an etcher, and possibly to bring new etchings to light. The project is published in partnership with The Leach Pottery, St Ives

Banks as real estate brokers -- letting free enterprise work

Gramm-Leach-Bliley Act