Pulsed laser deposition of anatase and rutile TiO2 thin films

The investigation deals with the preparation of both anatase and rutile thin films from a sintered rutile target of TiO₂ by pulsed laser ablation technique. Microstructural characterization of the sintered target was carried out using X-ray diffraction and AC impedance spectroscopy. Thin films of titania were deposited on (111) Si substrates at 673 K in the laser energy range 200-600 mJ/pulse at two different conditions: (i) deposition at 3.5 × 10^− 5 mbar of oxygen, and (ii) deposition at an oxygen partial pressure of 0.1 mbar. The influence of laser energy and oxygen addition on the film growth has been studied. X-ray diffraction analysis of the films indicated that the films are single phasic and nano crystalline. Titania films deposited in the energy range 200-600 mJ/pulse at a base pressure of 5 × 10^− 5 mbar are rutile with particle sizes in the range 5-10 nm, whereas the films formed at the oxygen partial pressure 0.1 mbar are anatase with particle sizes in the range 10-24 nm. In addition, at higher energies, a significant amount of particulates of titania are found on the surface of the films. The change in the microstructural features of the films as a function of laser energy and oxygen addition is discussed in relation with the interaction of the ablated species with the background gas.     

Nonionic surfactants induced cloud point extraction of Polyhydroxyalkanoate from Cupriavidus necator

Polyhydroxyalkanoate synthesized by Cupriavidus necator DSM 428 was purified from the crude fermentation broth as such by performing nonionic surfactants (Triton X100, Triton X114 & Tergitol 6) induced cloud point extraction. Polyhydroxyalkanoate was extracted into the micelle-rich bottom phase (coacervate phase), while most of the cellular impurities partitioned into the aqueous phase. Cloud point temperatures and the extraction efficiency of different cloud point systems were studied at different pH value and in the presence of additives. Maximum extraction of biopolymer was achieved (recovery of 84.4%) with a purity of 92.49% at 3 pH with the addition of 0.1 M ammonium chloride in the mixed surfactant system at a reduced cloud point temperature of 33°C.     

Internet of Things Enabled Energy Aware Metaheuristic Clustering for Real Time Disaster Management

Wireless Sensor Networks (WSNs) are a major element of Internet of Things (IoT) networks which offer seamless sensing and wireless connectivity. Disaster management in smart cities can be considered as a safety critical application. Therefore, it becomes essential in ensuring network accessibility by improving the lifetime of IoT assisted WSN. Clustering and multihop routing are considered beneficial solutions to accomplish energy efficiency in IoT networks. This article designs an IoT enabled energy aware metaheuristic clustering with routing protocol for real time disaster management (EAMCR-RTDM). The proposed EAMCR-RTDM technique mainly intends to manage the energy utilization of nodes with the consideration of the features of the disaster region. To achieve this, EAMCR-RTDM technique primarily designs a yellow saddle goatfish based clustering (YSGF-C) technique to elect cluster heads (CHs) and organize clusters. In addition, enhanced cockroach swarm optimization (ECSO) based multihop routing (ECSO-MHR) approach was derived for optimal route selection. The YSGF-C and ECSO-MHR techniques compute fitness functions using different input variables for achieving improved energy efficiency and network lifetime. The design of YSGF-C and ECSO-MHR techniques for disaster management in IoT networks shows the novelty of the work. For examining the improved outcomes of the EAMCR-RTDM system, a wide range of simulations were performed and the extensive results are assessed in terms of different measures. The comparative outcomes highlighted the enhanced outcomes of the EAMCR-RTDM algorithm over the existing approaches.     

In-situ PMMA modified <Emphasis Type="Italic">p-</Emphasis>cresol resin-nylon 6 polymer blends and evaluation of their hydrophobic and dielectric properties

The synthesis of PMMA modified p-Cresol resin-nylon 6 blends by the in-situ polymer blending in various proportion is described. These new polymer blends has been characterized by FT-IR, DSC-TGA, SEM, and screened for the hydrophobic, mechanical and dielectric properties. The blended materials exhibit good thermal stability and increased hydrophobic nature. Compressive stress and the strain study show that the blends have improved mechanical property. The frequency dependent dielectric property of the blend has been lowered. Thus, PMMA modified p-Cresol resin-nylon 6 blends could be used as a potential material for the fabrication of electronic device application.     

Direct evidence for purely silver ion conduction in CuI-doped silver oxysalt superionic systems: Combined electrolysis and EDS studies

Maiden attempt has been made for the direct estimation of the contributions of silver and copper ions to the ionic conductivity in superionic solids obtained in CuI-doped silver oxysalt systems. The application of the combined electrolysis and EDS techniques towards qualitative and quantitative analyses of the mobile ionic species in solid electrolyte systems having more than one possible mobile ion is reported. These studies confirmed that these electrolyte materials are purely Ag⁺ conducting up to 50 mol% CuI in xCuI–(100 − x)[2Ag₂O–0.7V₂O₅–0.3B₂O₃] and xCuI–(100 − x)[Ag₂O–0.7MoO₃–0.3WO₃] systems and small fraction of t_Cu+ exists above 60 mol% CuI. These solid electrolyte materials exhibited a high ionic transport numbers (t_i) of >0.985 and the t_i increases when two glass formers are used.     

Electrochemical studies on [M(diars)<Subscript>2</Subscript>X<Subscript>2</Subscript>]<Superscript>+</Superscript> where [X = Cl,Br; M = Os,Re, Ru,Rh; diars = <Emphasis Type="Italic">o</Emphasis>-phenylenebis (dimethylarsine)] at bare and Nafion modified electrodes

The voltammetric behaviour of the M(III/II) redox couple of the complexes of the general formula [M(diars)₂X₂]⁺ where M = Os, Re, Ru, Rh and diars = o-phenylenebis-(dimethylarsine) has been investigated in aqueous and aqueous/ethanol solvents at bare and Nafion modified electrodes. The formal reduction potential falls within the range of 0.097–0.0920 V and increases with the dielectric constant of the solvent. In acertonitrile, both the oxidized and reduced forms of the complex showed no adsorption at the surface of the glassy carbon electrode as shown by cyclic voltammetry. The electrochemistry is consistent with a quasireversible one electron transfer between the di and tri cationic forms of the complexes. A current-enhancement of ∼2 was observed at Nafion-modified glassy carbon over the bare electrode. Well defined voltammograms were obtained at Nafion-modified glassy carbon with a detectable signal down to 10⁻⁹ M range by differential pulse voltammetry. Electrochemical detection of dopamine in presence of [Os(4-mediars)₂Cl₂]⁺ at Nafion modified electrode indicates an increase in peak current. This shows that this complex acts as biochemical-sensor for dopamine.     

Effect of metal ions on reactive dye decolorization by laccase from Ganoderma lucidum

In this work, the influence of different metal ions on laccase activity and laccase-catalyzed dye decolorization was investigated under in vitro conditions using crude laccase obtained from a white rot fungus Ganoderma lucidum. Laccase activity was enhanced by metal ions such as Ca²⁺, Co²⁺, Cu²⁺ and Zn²⁺ at low concentrations (1 mM). Increasing the concentration of metal ions except that of Cu²⁺ and Zn²⁺ up to 5 mM and above decreased the enzyme activity. Among several heavy metals, Fe²⁺ highly inhibited the enzyme activity. Effect of metal ions was tested on decolorization of two reactive dyes, namely Remazol black-B (RB-5) and Remazol brilliant blue R (RBBR) at a concentration of 50 mg l⁻¹. The presence of heavy metals generally did not exert much influence on the decolorization except Fe²⁺. Cu²⁺ and Cr⁶⁺ enhanced the decolorization of both dyes. In the presence of 1 mM Cu²⁺, 94% of RB-5 and 35.5% of RBBR were decolorized during 1 h incubation. G. lucidum laccase was able to tolerate mixture of several metal ions. Treatment of simulated reactive dye effluent by laccase showed that the redox mediator system is necessary for effluent decolorization. Syringaldehyde, a natural redox mediator, was very effective than the synthetic mediator 1-hydroxybenzotriazole (HBT). The initial rate of effluent decolorization in presence of syringaldehyde (0.0831 h⁻¹) was 5.6 times higher than HBT (0.0152 h⁻¹). Although the rate of decolorization was markedly decreased in the effluent containing mixed metal ions, presence of syringaldehyde showed effective decolorization. This study indicates that G. lucidum laccase and natural redox mediator system could be a potential candidate for color removal from reactive dye effluent.     

Effect of coupling agents on the mechanical properties of fly ash/polyester particulate composites

Fly ash (FA)/general purpose unsaturated polyester resin (GPR) particulate composites were made. The effect of the surface treatment of FA with two different silane coupling agents (CAs) on the mechanical properties, such as the tensile, flexural, compressive, and impact strengths and hardness, of FA–GPR composites were studied. The properties of FA–CA–GPR were also compared with that of GPR and CaCO₃–GPR. An enhancement in the tensile, flexural, compressive, and impact strengths and a decrease in the tensile and flexural moduli were observed when FA was surface treated with CA. Hardness also increases with CA‐treated FA. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1755–1760, 2001     

Web engineering: an introduction

Within a short period, the Internet and World Wide Web have become ubiquitous, surpassing all other technological developments in our history. They've also grown rapidly in their scope and extent of use, significantly affecting all aspects of our lives. Industries such as manufacturing, travel and hospitality, banking, education, and government are Web-enabled to improve and enhance their operations. E-commerce has expanded quickly, cutting across national boundaries. Even traditional legacy information and database systems have migrated to the Web. Advances in wireless technologies and Web-enabled appliances are triggering a new wave of mobile Web applications. As a result, we increasingly depend on a range of Web applications. Now that many of us rely on Web based systems and applications, they need to be reliable and perform well. To build these systems and applications, Web developers need a sound methodology, a disciplined and repeatable process, better development tools, and a set of good guidelines. The emerging field of Web engineering fulfils these needs. It uses scientific, engineering, and management principles and systematic approaches to successfully develop, deploy, and maintain high-quality Web systems and applications. It aims to bring the current chaos in Web based system development under control, minimize risks, and enhance Web site maintainability and quality