In past decade, wireless sensor networks have gained attention by researchers, manufacturers as well as the users for remotely monitoring tasks and effective data gathering in diverse environment. The wireless sensor nodes are tiny battery powered devices having limited lifetime, hence for longevity and reliability, the foremost concern is minimizing energy consumption and maximizing network lifetime while designing protocols and applications. In this paper, we review the main design issues based on the model of wireless sensor networks: structurefree and structured for data collection and aggregation where role of clustering and routing is discussed for energy conservation and enhancing network lifetime. These design strategies are the foundation of any networking protocol from the energy saving point of view. A comprehensive tabular overview of different approaches under structurefree and structured wireless sensor networks for data collection and aggregation, clustering and routing is presented with key issues.
This report discussed the efficient hydrogen generation via water splitting and fast dye degradation pathway using Ce doped SnO 2 nanoparticles. One pot synthesis of Ce doped SnO 2 nanoparticles was carried out by a simple, convenient wet chemical method using H 2 O 2 and the product obtained was characterized using array of physico-chemical techniques. Powder X-ray diffraction confirmed the presence of rutile phase. Band gap for Ce:SnO 2 was found out to be 3.80 eV which is more than the pure SnO 2 (3.71 eV) and it is due to Moss-Burstein effect. EDAX analysis and elemental mapping support uniform distribution of 5% Ce and the SEM imaging depicts irregular shape of nanocrystallites. The doping of 5% Ce into the interstitial and lattice positions of SnO 2 nanoparticles was also confirmed by the X-ray photo-electron spectroscopy analysis. Raman measurement and photoluminescence analysis showed the presence of oxygen vacancies and disorderness in the nanoparticles. Photocatalytic water splitting proficiency was investigated using Ce doped SnO 2 nanomaterials in the presence of NiO as co-catalyst and other different sacrificial reagents such as methanol, Na 2 S-Na 2 SO 3 , EDTA ions, triethanolamine and in combinations. It was found that the evolution of H 2 is maximum i. e. 25 μmol/g/h in presence of as-synthesized catalyst, NiO (co-catalyst) along with EDTA and methanol as scavengers under UV light irradiation. Further, the degradation of methylene blue and methyl orange dyes was investigated under UV-Visible irradiation using Ce: SnO 2 NPs.[a] Dr.
Radical copolymerization of ␣-terpineol with styrene (Sty) initiated by azobisisobutyronitrile in xylene at 80 Ϯ 0.1°C for 2 h followed ideal kinetics and resulted in the formation of a functional and alternating copolymer as evidenced by spectral analysis. The activation energy was 28 kJ/mol. ␣-Terpineol underwent copolymerization as well as a chain-transfer reaction. The values of the monomer reactivity ratios calculated by the Kelen-Tü dos method were r 1 (Sty) ϭ 0.033 and r 2 (␣-terpineol) ϭ 0.004. The Alfrey-Price Q-e parameters for ␣-terpineol were calculated as 0.104 and 3.052, respectively. The mechanism of copolymerization is elucidated, and it is concluded that the double bond present in the monocyclic ring of ␣-terpineol is an active site for copolymerization.
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