1,846 research outputs found

    M-GEAR: Gateway-Based Energy-Aware Multi-Hop Routing Protocol for WSNs

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    In this research work, we advise gateway based energy-efficient routing protocol (M-GEAR) for Wireless Sensor Networks (WSNs). We divide the sensor nodes into four logical regions on the basis of their location in the sensing field. We install Base Station (BS) out of the sensing area and a gateway node at the centre of the sensing area. If the distance of a sensor node from BS or gateway is less than predefined distance threshold, the node uses direct communication. We divide the rest of nodes into two equal regions whose distance is beyond the threshold distance. We select cluster heads (CHs)in each region which are independent of the other region. These CHs are selected on the basis of a probability. We compare performance of our protocol with LEACH (Low Energy Adaptive Clustering Hierarchy). Performance analysis and compared statistic results show that our proposed protocol perform well in terms of energy consumption and network lifetime.Comment: IEEE 8th International Conference on Broadband and Wireless Computing, Communication and Applications (BWCCA'13), Compiegne, Franc

    Trajectories Describing the Evolution of Polarized Light in Homogeneous Anisotropic Media and Liquid Crystals

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    Trajectories are given that describe the evolution of the ellipse of polarization in the complex plane for light propagating in a homogeneous anisotropic medium and along the helical axis of a cholesteric liquid crystal. For the general homogeneous anisotropic medium that exhibits combined birefringence and dichroism the trajectory is a spiral that converges to the low-absorption eigenpolarization. For pure birefringence the trajectory becomes a complete circle that encloses one eigenpolarization, whereas for pure dichroism the trajectory becomes an arc of a circle that ends at the low-absorption eigenstate. The case of a cholesteric (or twisted nematic) liquid crystal leads to an interesting family of trajectories that can be considered as distorted hypo- or epicycloids. These trajectories are nonrepetitive (open) and may show multilobes or branches depending upon the initial polarization and the properties of the liquid crystal. Graphs are also presented where the ellipticity and azimuth are plotted separately as functions of distance along the helical axis

    Trajectories Describing the Evolution of Polarized Light in Homogeneous Anisotropic Media and Liquid Crystals

    Get PDF
    Trajectories are given that describe the evolution of the ellipse of polarization in the complex plane for light propagating in a homogeneous anisotropic medium and along the helical axis of a cholesteric liquid crystal. For the general homogeneous anisotropic medium that exhibits combined birefringence and dichroism the trajectory is a spiral that converges to the low-absorption eigenpolarization. For pure birefringence the trajectory becomes a complete circle that encloses one eigenpolarization, whereas for pure dichroism the trajectory becomes an arc of a circle that ends at the low-absorption eigenstate. The case of a cholesteric (or twisted nematic) liquid crystal leads to an interesting family of trajectories that can be considered as distorted hypo- or epicycloids. These trajectories are nonrepetitive (open) and may show multilobes or branches depending upon the initial polarization and the properties of the liquid crystal. Graphs are also presented where the ellipticity and azimuth are plotted separately as functions of distance along the helical axis

    Synthesis of Zeolite Y from Kaolin Using Novel Method of Dealumination

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    In this study Zeolite Y was successfully synthesized from local kaolin in Ado-0do Ota, Ogun state Nigeria through a novel process of dealumination. The thermal activation of kaolin was achieved through the process of metakaolinization at 850 oC for 6 hours in a furnace and dealumination with H2SO4 in order to achieve a desire silica/alumina molar ratio between 3 and 8. Zeolitization involved alkaline attack of dealuminated metakaolin and its consequent transformation into Zeolite Y crystal. Silica/Alumina molar ratio of 5.84 of metakaolin was synthesized under hydrothermal treatment with aqueous NaOH at atmospheric pressure. It was then aged for 7 days at room temperature and crystallized at 100 oC for 24 hours; Zeolite NaY of molar ratio of 3.46 was achieved and then modified to its hydrogen form by ion exchange with NH4Cl. The molar ratio of Zeolite Y in hydrogen form is 3.22. The samples were characterized with X-ray Fluorescence (XRF), X-Ray Diffraction (XRD), and Scanning Electron Microscope (SEM). The result showed that zeolite Y was synthesized from Arobieye mined kaolin with a molar ratio of 6SiO2 : Al2O3 : 9Na2O : 24H2O by ageing at room temperature for 24 hours and crystallized at 100 oC for 24 hours

    Features of Islamic websites, perceptions of Muslim users and utilization behavior: a conceptual model

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    Islamic websites demand special attention due the nature of the content delivered to the users. To deliver satisfying online knowledge and practice for Muslim Ummah, it is important to identify and evaluate the overall features of Islamic website (Iweb). In this paper, we explore the literature on Islamic website and e-consumer and developed a conceptual model that identifies perceived Muslim user satisfaction. The paper examines three issues namely; features of Iweb user satisfaction, perceived dimensions of this satisfaction judgment, and consequence of Muslim user satisfaction with Iweb

    Uniting Students with Literacy Connections in Mathematics

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    Literature provides opportunities for students to connect to mathematics, as well as each other. Reflecting on personal identities, storytelling, and place-based connections are avenues to enhancing the relevancy of content across the curriculum. Literature can bridge the divide for students reluctant to see the beauty in mathematics. It can also be the impetus in helping unite students as they gain a better understanding of cultures and places beyond their own. Stories, along with interactive tasks, give context for collaborative experiences. This article shares resources and strategies for building understanding and collaboration among students using cross-curricular connections between mathematics and literacy

    Comparative Assessment of Sweet (Zeamays Convar.Saccarata) and Dent Maize (Zeamays) for Phytoremediation of Chromium and Nickel Polluted Agricultural Soils

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    The consequential effects of heavy metal consumption by man suggest the need for plant assessment for bio-concentration and translocation potentials. This study aimed at comparing the potential of dent maize with sweet maize for phytoremediation of Chromium (Cr) and Nickel (Ni) contaminated soils. Soil samples were taken randomly to a depth of 20 cm. Out of the samples taken; about 500 g of the samples were homogenized, dried, sieved, and used for the determination of soil physicochemical properties. The remaining soil samples were used to fill the polythene bags for the plant growth. The experimental design used was 22 by 2 general factorial design consisting of 4 treatments (1 g/dm3 of Ni (NO3)2.6H2O; 3 g/dm3 of Ni (NO3)2.6H2O; 1 g/dm3 of Cr (NO3)2.9H2O and 3 g/dm3 of Cr (NO3)2.9H2O), 2 replicates of each and the control. The setup was made for each of the maize types. Three seeds of maize were planted on each of the soil samples at a depth of 4 cm and the setup was properly monitored. Soil samples were analyzed at day 1 and every 14 days interval in a period of 70 days after planting (DAP). The result of the initial analysis of the soil samples indicates that the control soil sample contained 0.17+0.002 mg/kg of Cr and 0.03+0.001 mg/kg of Ni for soil seeded with both the dent and sweet maize. The mean concentration of Cr and Ni from the soil samples taken from soil contaminated with 1g treatment were 1.24+0.001 mg/kg and 1.43+0.002 mg/kg respectively, while that contaminated with 3g treatment has 3.98+0.02 mg/kg of Cr and 2.96+0.02 mg/kg of Ni. The results also show a reduction in the heavy metal concentrations of the soil through the 70 days of planting. The Cr and Ni contents of the two maize types increase with the increase in the amount of metals (3 g > 1 g> control) in the soils in which they were seeded. Though, the two types of maize are good phytoplant, sweet maize is more active in Cr removal than dent maize. The two maize types are better in bioaccumulation than in translocation. The growth of the plants was not retarded by the presence of the metal which shows their tolerance and effectiveness in remediating Cr and Ni contaminated soil. The use of this technology will help in attaining sustainable development goals as it addresses the problem of environmental degradation while the subsistence agriculture will be promoted and hence poverty will also be alleviated or eradicated

    The establishment of a future NESP dredging research investment framework: NESP TWQ Hub Project 1.9

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    The purpose of this project was to conduct a facilitated workshop with key researchers and stakeholders to establish priorities for future research investment of the NESP Tropical Water Quality Hub (NESP TWQ) into dredging and disposal of dredged sediments in the GBR. A recent independent review of potential impacts of dredging on the biological values of the Great Barrier Reef (GBR) identified a number of key knowledge gaps that need to be addressed to improve management of dredging1 activities. That review, together with the findings of the currently underway dredging science node of the Western Australian Marine Institution (WAMSI), informed the subsequent prioritisation of research topics to address the most important knowledge gaps

    A report card approach to describe temporal and spatial trends in parameters for coastal seagrass habitats

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    Report cards that are designed to monitor environmental trends have the potential to provide a powerful communication tool because they are easy to understand and accessible to the general public, scientists, managers and policy makers. Given this functionality, they are increasingly popular in marine ecosystem reporting. We describe a report card method for seagrass that incorporates spatial and temporal variability in three metrics—meadow area, species and biomass—developed using long-term (greater than 10 years) monitoring data. This framework summarises large amounts of spatially and temporally complex data to give a numeric score that provides reliable comparisons of seagrass condition in both persistent and naturally variable meadows. We provide an example of how this is applied to seagrass meadows in an industrial port in the Great Barrier Reef World Heritage Area of north-eastern Australia
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