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.
We report a detailed study on the electromagnetic interference (EMI) shielding effectiveness (SE) properties in La 0.7 Sr 0.3 MnO 3 (LSMO) nanomaterials. The samples were prepared by a solution chemistry (sol-gel) route at different sintering temperatures. The single-phase samples with grain sizes of 22 and 34 nm showed DC electrical conductivity variation from 0.65 to 13 S cm À1 at room temperature. The application of a high magnetic field resulted in higher conductivity values. The electrical conductivity variation with temperature could be fitted with a variable range hopping mechanism in a limited temperature range.The variation of frequency dependent electromagnetic parameters measured at room temperature within the X-band region is consistent with the electrical conductivity behavior. The complex permittivity and permeability parameters were determined in line with the Nicolson-Ross-Weir algorithm. The LSMO nanomaterial samples showed EMI shielding effectiveness values of up to 19 dB (96.3% attenuation) over the X-band frequency range, making them suitable for microwave radiation shielding in commercial and defense appliances.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.