AN EFFICIENT LOAD BALANCING CLUSTERING SCHEME FOR DATA CENTRIC WIRELESS SENSOR NETWORKS

Clustering is an efficient approach to capitalize the energy of energy constraint sensor nodes in wireless sensor networks. Clustering schemes do not guarantee formation of clusters with equal number of nodes. So data frames transmitted by the nodes vary. TDMA schedule of nodes of smaller cluster is smaller than others that results more number of data frames and hence more energy consumption. The non uniform energy consumption of nodes affects the load balancing of network and these nodes are more prone to die earlier than others. In this paper, an improved scheme for cluster head selection is proposed. Clusters having variable frame slots for nodes are applied to E-LEACH and improved E-LEACH to make the cluster more load balanced. Simulation is carried out in NS-2 to analyze the performance of E-LEACH and improved E-LEACH with variable frame length. Variable frame slot scheme for clusters is also measured with the varying distance of base station from the field. Simulation results show that clustering with variable frame length has an improvement of 7% in node death rate over E-LEACH and an improvement of 9% in node death rate over improved ELEACH. Results suggest that variable frame length scheme improves the performance of clustering schemes for WSNs and have most significant result at base station located at 75m from the field

Mercury or Mercury Free Restorations in Oral Cavity

Amalgam is basically a concoction of metals that has been used as a potent filling material in dentistry for the last 150 years. Amalgam usually consists of silver, mercury, tin and copper. Dental amalgam is a material used to fill cavities of tooth. Over the years, amalgam has become a topic of concern because it contains mercury. Mercury is a naturally occurring metal in the environment. Mercury exists as a liquid in room temperature but when heated, it becomes a gas. Flexibility of amalgam as a filling material is due Mercury. An alloy powder, a compound that is soft in nature when mixed with mercury makes it enough to mix and condense into the tooth. It hardens quickly and offers strong resistance to the forces of biting and chewing. There are studies reported on the safety of amalgam fillings. In 2005, European Union launched a comprehensive mercury strategy to reduce use of mercury. In 2008, countries like Norway and Denmark restricted the use of dental amalgam containing mercury. In 2009, this research was evaluated by U.S. Food and Drug Administration (FDA) and found no rationale to limit the use of amalgam. There are certain restorative materials that are available commercially that are mercury free in nature like Gold, Porcelain, Gallium alloys, Composite resin restoratives etc. They offer many advantages over amalgams containing mercury like: seals the dentin from future decay, reinforces remaining tooth structure, provides smooth and bonded margins, conservative and it blends naturally

Cosmic ray intensity distribution perpendicular to solar equatorial plane at 1 A.U. during 1978-83

The distribution of cosmic ray intensity perpendicular to solar equatorial plane, was investigated by using its yearly variation with respect to the heliolatitudinal position of the Earth, for the two intervals 1978 to 1980 and 1981 to 1983. The monthly mean values of two high latitude stations along with the solar and geomagnetic indices are used to derive the cosmic ray intensity distribution free from the changes due to variation in solar activity. The correction is found to be significant only during the interval 1976 to 1980. The results indicate a significant linear increase in cosmic ray intensity from north to south of solar equator, contrary to that observed during 1973 to 1975. No symmetrical gradients are found during the period of study, in agreement with earlier results

Assessment of Immunotoxic Response in Albino Rats Following Nickel Nitrate Treatment

Nickel nitrate affects body physiology and immunology following its absorption through food, water, air. Predetermined doses of nickel nitrate (Ni(NO3)2] in acute (1 d) and subacute (7, 14, 21 ds) treatments revealed a significant increase in IgG concentration and lymphocyte number, whereas, neutrophils and eosinophils registered significant fall. These alterations indicated heavy metal stress in Immunological parameters that become targets