SignText: a web-based tool for providing accessible text book contents for Deaf learners

Universal Access in the Information Society - Lack of Sign Language-based learning tools is a hindrance in acquiring knowledge for deaf students. Technology-based tools have introduced innovative...     

Synthesis and characterization of poly(ethylene oxide)‐based glycopolymers and their biocompatibility with osteoblast cells

Poly(ethylene oxide)‐block‐poly(methacryl‐d ‐glucopyranoside) (PEO‐GP) and poly(methacryl‐d ‐glucopyranoside) (H‐GP) glycopolymers were synthesized by deacetylation of acetylated polymers which were synthesized via atom transfer radical polymerization. The synthesized glycopolymers were characterized using ¹H NMR, ¹³C NMR and Fourier transform infrared (FTIR) spectroscopies, gel permeation chromatography (GPC), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The deacetylated polymers exhibited onset decomposition temperatures about 60 °C lower compared to the polymers having acetyl pendants. The glass transition temperature (T_g) of the acetylated homopolymer was 133 °C and that of the PEO‐based block copolymer was 124 °C. The deacetylated polymers H‐GP and PEO‐GP exhibited T_g values of about ?30 °C. Biocompatibility of the H‐GP and PEO‐GP glycopolymers was obtained by studying osteoblast cell adhesion, viability and proliferation in vitro. The cell viability showed an increase with increasing concentration of H‐GP from 0.1 to 1 µmol L^?1 and then decreased with further increase in its concentration (10–1000 µmol L^?1). PEO‐GP did not show a significant variation in cell viability on variation of its concentration from 0.1 to 1000 µmol L^?1. The significant improvement in biocompatibility with osteoblast cells in the presence of PEO‐GP was considered as due to the covalently bonded PEO segment of the methacrylate glycopolymer block. © 2014 Society of Chemical Industry     

Triangular‐shaped super‐thin microwave network cloak in antenna applications

In this research article, a triangular‐shaped microwave network cloak made out of interconnected patches was designed at the frequency of 2.88 GHz. Its performances in terms of field distributions and radar cross section scattering were compared with the existing structures. The novel triangular‐shaped cloak structure was then applied to cloak a hindering obstacle placed in front of an electromagnetic source. The simulated scattering parameter and radiation pattern of antenna source were then validated through the experimental results. Also, the proposed structure was applied to reduce the mutual interference between two neighboring antennas. The effects of various parameters such as position and size of the cloak, dielectric constant, and substrate thickness on the cloaking effect were also simulated and studied.     

Effect of strain in PbSe/ZnPc stacked layers prepared by thermal evaporation method

The article investigates the structural and optical properties of ZnPc/PbSe hybrid multilayer (HML) structure deposited by using thermal evaporation technique. The X-ray diffraction pattern reveals the formation of ZnPc–PbSe composite and strain induced quantum size effect. Scanning electron microscope image shows the spherical grains for as-deposited film and nanorod like structure for the annealed film. The rods are oriented along one direction and stacking axis changes with the function of annealing temperature. The optical spectra show strong absorption in UV–Visible region and the optical absorption edge was red shifted for annealed samples. The luminescence properties were enhanced with broad emission in the range of 375–400 nm in HMLs. The optical band gap values are calculated and it varies from 3.2 to 3.04 eV with the function of annealing temperature and the band gap splitting was observed for a higher temperature of annealed samples. Strain-induced effect on ZnPc/PbSe HML has been reported using Raman spectra.     

Investigation of structural,mechanical and magnetic characterization of electroplated W deposited NiMo thin films

Journal of Materials Science: Materials in Electronics - In the current research work, NiMo thin films were successfully co-deposited with W on the copper substrate (NiMoW) by varying the plating...     

An Efficient Information System for Providing Location Based Services in Network Environments

Wireless Personal Communications - In information retrieval systems, the location information can be collected by using Global Positioning Systems for providing Location Based Services (LBS) to the...     

Energy efficient secured K means based unequal fuzzy clustering algorithm for efficient reprogramming in wireless sensor networks

Wireless Networks - Wireless Sensor Networks (WSNs) is a collection of tiny distributed sensor nodes that have been used to sense the physical parameters of the environment where it has been...     

Sustainable life-span of WSN nodes using participatory devices in pervasive environment

Wireless sensor network being a dominant prerequisite in the modern pervasive environment has nodes connected with multi-hop to transmit and reinforce continuous monitoring with real-time updates from the field environment. To achieve pervasiveness integrating wireless and physical devices is unavoidable. Numerous self-organized tiny sensor nodes cooperate with each other to form the clusters and the most prominent node act as cluster head (CH). The cluster head pioneered based on its battery forte whose failure affects rest of the communications. In this paper, we discuss on the essential of idle resource sharing using participatory devices as relay nodes along with node failure rate and node density to achieve reliable communication. The earlier performances are observed and results are revealed. Hence we concentrate on minimizing the task of CH using relay nodes such as participatory devices and the faulty nodes are identified over Poisson distribution which observes the failure probability without affecting communication and reduced resource consumption.

     

Electrocatalytic oxidation of ascorbic acid using a single layer of gold nanoparticles immobilized on 1,6-hexanedithiol modified gold electrode

This paper describes the electrocatalytic oxidation of ascorbic acid (AA) in phosphate buffer solution by the immobilized citrate capped gold nanoparticles (AuNPs) on 1,6-hexanedithiol (HDT) modified Au electrode. X-ray photoelectron spectrum (XPS) of HDT suggests that it forms a monolayer on Au surface through one of the two SH groups and the other SH group is pointing away from the electrode surface. The free SH groups of HDT were used to covalently attach colloidal AuNPs. The covalent attachment of AuNPs on HDT monolayer was confirmed from the observed characteristic carboxylate ion stretching modes of citrate attached with AuNPs in the infra-red reflection absorption spectrum (IRRAS) in addition to a higher reductive desorption charges obtained for AuNPs immobilized on HDT modified Au (Au/HDT/AuNPs) electrode in 0.1 M KOH when compared to HDT modified Au (Au/HDT) electrode. The electron transfer reaction of [Fe(CN)₆]^4−/3− was markedly hindered at the HDT modified Au (Au/HDT) electrode while it was restored with a peak separation of 74 mV after the immobilization of AuNPs on Au/HDT (Au/HDT/AuNPs) electrode indicating a good electronic communication between the immobilized AuNPs and the underlying bulk Au electrode through a HDT monolayer. The Cottrell slope obtained from the potential-step chronoamperometric measurements for the reduction of ferricyanide at Au/HDT/AuNPs was higher than that of bare Au electrode indicating the increased effective surface area of AuNPs modified electrode. The Au/HDT/AuNPs electrode exhibits excellent electrocatalytic activity towards the oxidation of ascorbic acid (AA) by enhancing the oxidation peak current to more than two times with a 210 mV negative shift in the oxidation potential when compared to a bare Au electrode. The standard heterogeneous electron transfer rate constant (k_s) calculated for AA oxidation at Au/HDT/AuNPs electrode was 5.4 × 10⁻³ cm s⁻¹. The oxidation peak of AA at Au/HDT/AuNPs electrode was highly stable upon repeated potential cycling. Linear calibration plot was obtained for AA over the concentration range of 1–110 μM with a correlation coefficient of 0.9950. The detection limit of AA was found to be 1 μM. The common physiological interferents such as glucose, oxalate ions and urea do not show any interference within the detection limit of AA. The selectivity of the AuNPs modified electrode was illustrated by the determination of AA in the presence of uric acid.     

Calcined hydrotalcites for the catalytic decomposition of N2O in simulated process streams

Various hydrotalcite based catalysts were prepared for testing for the catalytic decomposition of N₂O. CoAl, NiAl, Co/PdAl, Co/RhAl, and Co/MgAL substituted hydrotalcites and CoLaAl hydroxides offer very good activity at modest temperatures. Precalcination of these materials at ca. 450–500°C, which destroys the hydrotalcite phase, is necessary for optimum activity and life. For Co substituted hydrotalcites, the optimal ratio of Co/Al is 3.0. The temperature for 50% conversion of N₂O of these calcined cobalt hydrotalcites is ca. 75°C lower than for the previous highly active Co-ZSM-5. These calcined cobalt hydrotalcite materials display sustained life at temperatures in excess of 670°C in an O₂ rich, wet stream with high levels of N₂O [10%]. Excess O₂ does not seriously impact N₂O decomposition, but the combination of both water vapor and O₂ does reduce activity by ca. 50%.