An analytical geometric range free localization scheme based on mobile beacon points in wireless sensor network

In many applications of wireless sensor network, the position of the sensor node is useful to identify the actuating response of the environment. The main idea of the proposed localization scheme is similar with most of the existing localization schemes, where a mobile beacon with global positioning system broadcast its current location coordinate periodically. The received information of the coordinates help other unknown nodes to localize themselves. In this paper, we proposed a localization scheme using mobile beacon points based on analytical geometry. Sensor node initially choose two distant beacon points, in-order to minimize its residence area. Later using the residence area, sensor node approximate the radius and half length of the chord with reference to one of the distant beacon point. Then the radius and half length of the chord are used to estimate the sagitta of an arc. Later, sensor node estimate its position using radius, half length of the chord, and sagitta of an arc. Simulation result shows the performance evaluation of our proposed scheme on various trajectories of mobile beacon such as CIRCLE, SPIRAL, S-CURVE, and HILBERT.     

Eigenvalue equation and core-mode cutoff of weakly guiding tapered fiber as three layer optical waveguide and used as biochemical sensor

The core-mode cutoff plays a major role in evanescent field absorption based sensors. A method has been proposed to calculate the core-mode cutoff by solving the eigenvalue equations of a weakly guiding three layer optical waveguide graphically. The variation of normalized waveguide parameter (V) is also calculated with different wavelengths at core-mode cutoff. At the first step, theoretical analysis of tapered fiber parameters has been performed for core-mode cutoff. The taper angle of an adiabatic tapered fiber is also analyzed using the length-scale criterion. Secondly, single-mode tapered fiber has been developed to make a precision sensor element suitable for chemical detection. Finally, the sensor element has been used to detect absorption peak of ethylenediamine. Results are presented in which an absorption peak at 1540 nm is observed.     

Synthesis, photophysical, electrochemical and thermal studies on carbazole-based acceptor molecules for heterojunction solar cell

Five small molecules, 3-tricyanovinyl-N-alkylcarbazoles (6-10) have been synthesized in a cost-effective way and characterized. The molecules have high thermal stability, good thin film formation ability and are also air stable. The change of alkyl chain length altered the aggregation pattern in the thin film. Their photophysical and electrochemical studies promise a compatible highest occupied molecular orbital - lowest unoccupied molecular orbital energy level to be potentially useful as good electron acceptor materials in heterojunction solar cell in combination with copper(II)phthalocyanine or poly-3-hexylthiophene (P3HT) as donor. Significant photoluminescence quenching of P3HT in P3HT:6-10 blends were observed.     

Young citizens’ knowledge and perceptions of bioenergy and future policy implications

In the past few years extensive discussions on bioenergy has been both positive and negative. In Europe, the image of bioenergy appears to be low with lack of broad public support. Previous studies show that younger people are unsure about many issues surrounding renewable energy. The aim of this study was to investigate the knowledge and perceptions of bioenergy among pupils in North Karelia, Finland. Data drawn from 495 ninth grade students indicate that the majority of them lack in-depth knowledge about different renewable energy sources, including bioenergy. Only a small percentage has a ‘high’ level of knowledge about bioenergy and the majority indicates critical perceptions of it. Statistically significant gender differences are not apparent. Girls appear to be more knowledgeable than boys. Results also show a clear ‘urban’ and ‘rural’ difference in perceptions of bioenergy. Perceptions of urban respondents being more positive than that of their rural counterparts. Developing collaboration between future bioenergy policies and bioenergy education for younger citizens is necessary for their engagement in critical debates on bioenergy.     

Upconversion luminescence in Tm3+/Yb3+ co-doped double-clad silica fibers under 980 nm cladding pumping

An investigation is reported of the visible and near-infrared upconversions in Tm³⁺/Yb³⁺ co-doped double-clad silica fibers (TYDFs) under excitation at 980?nm. The TYDFs used were fabricated using the modified chemical vapor deposition (MCVD) and solution doping techniques. Three distinct upconversion luminescences were observed at wavelengths of 482, 649 and 816?nm and their intensities found to increase with Yb³⁺ concentration. The intensity of blue and red fluorescence bands at 482 and 649?nm were found to be the highest with LTY-8 fiber, which had Tm³⁺ and Yb³⁺ concentrations of 5.6?×?10¹⁹ and 15.5?×?10¹⁹ ions/cc, respectively. The upconversion luminescence intensity was also observed to decrease with an increase in temperature. The main emission switched from 482?nm to 816?nm as the temperature increased above 200°C.     

Consumption of brown rice: a potential pathway for arsenic exposure in rural Bengal

This study assesses the arsenic (As) accumulation in different varieties of rice grain, that people in rural Bengal mostly prefer for daily consumption, to estimate the potential risk of dietary As exposure through rice intake. The rice samples have been classified according to their average length (L) and L to breadth (B) ratio into four categories, such as short-bold (SB), medium-slender (MS), long-slender (LS), and extra-long slender (ELS). The brown colored rice samples fall into the SB, MS, or LS categories; while all Indian Basmati (white colored) are classified as ELS. The study indicates that the average accumulation of As in rice grain increases with a decrease of grain size (ELS: 0.04; LS: 0.10; MS: 0.16; and SB: 0.33 mg kg(-1)), however people living in the rural villages mostly prefer brown colored SB type of rice because of its lower cost. For the participants consuming SB type of brown rice, the total daily intake of inorganic As (TDI-iAs) in 29% of the cases exceeds the previous WHO recommended provisional tolerable daily intake value (2.1 μg day(-1) kg(-1) BW), and in more than 90% of cases, the As content in the drinking water equivalent to the inorganic As intake from rice consumption (C(W,eqv)) exceeds the WHO drinking water guideline of 10 μg L(-1). This study further demonstrates that participants in age groups 18-30 and 51-65 yrs are the most vulnerable to the potential health threat of dietary As exposure compared to participants of age group 31-50 yrs, because of higher amounts of brown rice consumption patterns and lower BMI.     

Testing tubewell platform color as a rapid screening tool for arsenic and manganese in drinking water wells

A low-cost rapid screening tool for arsenic (As) and manganese (Mn) in groundwater is urgently needed to formulate mitigation policies for sustainable drinking water supply. This study attempts to make statistical comparison between tubewell (TW) platform color and the level of As and Mn concentration in groundwater extracted from the respective TW (n = 423), to validate platform color as a screening tool for As and Mn in groundwater. The result shows that a black colored platform with 73% certainty indicates that well water is safe from As, while with 84% certainty a red colored platform indicates that well water is enriched with As, compared to WHO drinking water guideline of 10 μg/L. With this guideline the efficiency, sensitivity, and specificity of the tool are 79%, 77%, and 81%, respectively. However, the certainty values become 93% and 38%, respectively, for black and red colored platforms at 50 μg/L, the drinking water standards for India and Bangladesh. The respective efficiency, sensitivity, and specificity are 65%, 85%, and 59%. Similarly for Mn, black and red colored platform with 78% and 64% certainty, respectively, indicates that well water is either enriched or free from Mn at the Indian national drinking water standard of 300 μg/L. With this guideline the efficiency, sensitivity, and specificity of the tool are 71%, 67%, and 76%, respectively. Thus, this study demonstrates that TW platform color can be potentially used as an initial screening tool for identifying TWs with elevated dissolved As and Mn, to make further rigorous groundwater testing more intensive and implement mitigation options for safe drinking water supplies.     

An innovative technique to evaluate network equivalent for voltage stability assessment in a widespread sub-grid system

The equivalent two-bus network models currently available are obtained by lumping all the series impedances and shunt admittances of transmission lines within a series equivalent impedance, to assess voltage stability of multi-bus power system. This paper reports the development of an equivalent pi-network model using a new methodology considering series and shunt parts of line loss separately obtained from the operational parameters of optimal power flow solution of the original multi-bus power network, which can be applied to assess the overall voltage stability status of the system accurately by developing the concept of a generalized global voltage stability margin (GVSM). Simulation results for a typical longitudinal power supply (LPS) system and a robust practical (Indian Eastern Grid) system establish that the pi-equivalent model obtained by the proposed method is highly promising for assessing voltage stability of any power system at any operating point in global scenario in a better way as compared to available series equivalent model. Continuation power flow (CPF) method has also been adopted here to verify the potential of the proposed method for voltage stability assessment. In the proposed equivalent network the generators have been modeled more accurately considering optimal operating criteria.     

Online Distributed Fault Diagnosis in Wireless Sensor Networks

This paper presents an online fault diagnosis algorithm for wireless sensor networks. This work explicitly takes into account the possibility of faults in different sections of sensor networks and communication channel. The diagnostic local view is obtained by exploiting the spatially correlated sensor measurements. These local views are then disseminated using a spanning tree of cluster heads. Our algorithm is shown to be energy efficient as it works in conjunction with the normal network activities and requires minimum additional diagnostic messages to be exchanged. Simulation results show that the performance of our algorithm is less sensitive to the average node degree for a wide range of fault rates.