Distributed topology management for wireless multimedia sensor networks: exploiting connectivity and cooperation

In this paper, we propose a distributed topology management algorithm, named T‐Must, which orchestrates coalition formation game between camera and scalar sensor (SS) nodes, for use in wireless multimedia sensor networks. In the proposed solution, connectivity among the peer camera sensor (CS) nodes is maintained, and coverage is ensured between them. Only the scalar data are not sufficient to describe an event in a particular monitored area. In many cases, multimedia data (specifically, video data) are required to provide more precise information about the event. As the CS nodes, which sense and transmit multimedia data, are costlier than the SS nodes, the former are deployed in the monitored area in lesser numbers compared to the latter ones. In case of CS nodes, power consumption due to sensing is also significant, similar to power consumption for the transmission and reception of packets. Therefore, in this work, in order to increase the network lifetime, topology is controlled by forming coalition between the CS and SS nodes. Upon occurrence of an event, the SS nodes send scalar data to their associated CS nodes. If the scalar data received from SS nodes cross a preconfigured threshold, the associated CS node in the coalition starts sensing the event, captures the video data, and forwards the video data toward other coalitions or sink. Copyright © 2014 John Wiley & Sons, Ltd.     

Analytical and numerical solution of the longitudinal porous fin with multiple power-law-dependent thermal properties and magnetic effects

The present study is concentrated on the application of electric and magnetic fields on the longitudinal porous fin with power-law-dependent heat transfer coefficient, surface emissivity, and heat generation. The porosity parameter controls the amount of empty spaces or voids in the porous fin and its practical value lies in the range $0\angle \varphi \angle 1$. In industrial application, the heat transfer coefficient is governed by a power law and its specific value defines a certain heat transfer process. The heat generation and surface emissivity of the longitudinal porous fin are assumed to be varied according to the power law and the whole fin is under the influence of an external electric field. The resulting nonlinear equation is solved by the classical Adimian decomposition method (ADM) and the obtained solutions are verified further by the finite difference method (FDM). It has been found that both ADM and FDM are in good agreement for lower values of thermophysical parameters. The effects of power index of heat generation, surface emissivity, and heat transfer coefficient parameter on the temperature distribution, heat flux, and efficiency are analyzed at different values of the porosity parameter comprehensively.     

Novel low-cost approach for removal of surface contamination before texturization of commercial monocrystalline silicon solar cells

This paper reports a novel approach on the surface treatment of monocrystalline silicon solar cells using an inorganic chemical, sodium hypochlorite (NaOCl) that has some remarkable properties. The treatment of contaminated crystalline silicon wafer with hot NaOCl helps the removal of organic contaminants due to its oxidizing properties. The objective of this paper is to establish the effectiveness of this treatment using hot NaOCl solution before the saw damage removal step of the conventional NaOH texturing approach. A comparative study of surface morphology and FTIR analyses of textured monocrystalline silicon surfaces with and without NaOCl pre-treatment is also reported. The process could result in a significant low cost approach viable for cleaning silicon wafers on a mass production scale.     

Hydrogeochemistry,Elemental Flux,and Quality Assessment of Mine Water in the Pootkee-Balihari Mining Area,Jharia Coalfield,India

Ninety nine mine water discharge samples were collected and analyzed for pH, electrical conductivity (EC), major cations, anions, and trace metals in the Pootkee-Balihari coal mining area of the Jharia coalfield. The mines of the area annually discharge 34.80 × 10⁶ m³ of mine water and 39,099 t of solute loads. The pH of the analyzed mine waters ranged from 6.97 to 8.62. EC values ranged from 711 μS cm⁻¹ to 1862 μS cm⁻¹, and reflect variations in lithology, geochemical processes, and hydrological regimes in the mines. The cation and anion chemistry indicate the general ionic abundance as: Mg²⁺ > Ca²⁺ > Na⁺ > K⁺ and HCO₃ ⁻ > SO₄ ²⁻ > Cl⁻ > NO₃ ⁻ > F⁻, respectively. Elevated SO₄ ²⁻ concentrations in the Gopalichuck, Kendwadih, and Kachhi-Balihari mine waters are attributed to pyrite weathering. The water quality assessment indicated that TDS, hardness, Mg²⁺, and SO₄ ²⁻ are the major parameters of concern in the study area. Except for Fe, all of the measured metals in the mine water were well within the levels recommended for drinking water. With only a few exceptions, the mine water is of good to permissible quality and suitable for irrigation.     

Tannase production by Bacillus licheniformis KBR6: Optimization of submerged culture conditions by Taguchi DOE methodology

Tannase production by Bacillus licheniformis KBR6 under submerged fermentation was optimized following Taguchi orthogonal array (OA) design of experiment (DOE). An OA layout of L18 (2¹ × 3⁵) was constructed with six most influensive factors on tannase biosynthesis like, carbon source (tannic acid), phosphate source (KH₂PO₄), nitrogen source (NH₄Cl), metal ion (Mg²⁺), incubation temperature and initial medium pH at three levels for the proposed experimental design. Tannase yield obtained from the 18 batches fermentation with the selected levels of each factors were processed with Qualitek-4 software at bigger is better as quality character and obtained a specific combination of factors with a predicted tannase production of 0.362 U/ml. The optimal combinations of factors (tannic acid, 1.0 g%; KH₂PO₄, 0.45 g%; NH₄Cl, 0.35 g%; MgSO₄, 0.05 g%) obtained from the proposed DOE methodology was further validated by fermentation experiment and the obtained result revealed an enhanced tannase yield of 2.18-fold (from 0.163 U/ml to 0.356 U/ml) from its unoptimized condition. Taguchi approach of DOE resulted in evaluating the main and interaction effects of the factors individually and in combination.     

MESFET MMIC Ka-band transmitter performance forhigh-volume system applications

An MMIC transmitter for high-volume smart munition applications in Ka band is developed using 0.25 μm MESFET technology. The transmitter, consisting of a voltage-controlled oscillator (VCO) and power amplifier (PA), delivers more than 100 mW of power with an overall efficiency of 10% and a linear tuning range of more than 700 MHz around 35 GHz     

Effect of chemical composition and initial heat treatment on the structure and properties of a few dual-phase steels

Dual-phase structures are produced in the three experimental steels, namely A1, A2 and A3, a) by air-cooling from the austenitising temperature (910°C) and then intercritically annealing the ferrite-pearlite structure at 750°C and 810°C followed by water quenching, and b) by water-quenching from the same austenitising temperature and then intercritically annealing the martensitic structure again at 750°C and 810°C followed by water quenching. The ferrite phases present in the alloys A1 and A2 have formed in two different ways: i) before and/or during intercritical annealing (old ferrite) and ii) during cooling of the alloys from the intercritical annealing temperature (new ferrite). The amount of new ferrite has been found to be larger in alloy A1 as compared to alloy A2. Alloy A3 did not show any measurable amount of new ferrite. TEM studies did not reveal any significant difference in microstructure in any of the alloys as a result of the initial heat treatment. The volume percent of martensite is maximum in alloy A2 and minimum in alloy A1, with alloy A3 coming in between. Although the amount of martensite in alloy A1 is somewhat lower than that in alloy A3, the overall strength of alloy A1 is higher than that of alloy A3 due possibly to the significant solid solution hardening of the ferritic matrix caused by silicon. Alloy A2 has been found to have the highest strength amongst the three alloys.     

Treatment of simulated arsenic contaminated groundwater using GAC‐Cu in batch reactor: Optimization of process parameters

This article deals with the experimental investigation related to the removal of arsenic from a simulated contaminated groundwater by the adsorption onto Cu²⁺ impregnated granular activated carbon (GAC‐Cu) in presence of impurities like Fe and Mn. The effects of adsorbent concentration, pH, and temperature on the percentage removal of total arsenic (As(T)), As(III), and As(V) have been discussed. Under the experimental conditions, the optimum adsorbent concentration for GAC‐Cu has been found to be 6 g/L with an agitation time of 24 h, which reduces the As(T) concentration from 188 to 8.5 µg/L. Maximum removal of As(V) and As(III) has been observed in the pH range of 7–9 and 9–11, respectively. Removal of all the above said arsenic species decreases slightly with increase in temperature. Presence of Fe and Mn increases the adsorption of arsenic species. Under the experimental conditions, at 30°C, maximum % removals of As(T), As(III), As(V), Fe, and Mn are found to be 95.5%, 93%, 98%, 100%, and 40%, respectively. It has also been observed that maximum regeneration (～94%) of spent GAC‐Cu is exhibited by a 5NH₂SO₄ solution.