FDRF: Fault Detection and Recovery Framework for Seamless Data Transmission in Remote Health Monitoring Using WBAN

Wireless Personal Communications - Health monitoring systems based on Sensors, IoT and Cloud server have gained popularity in recent time. In this work patient either wear small sensors or they are...     

Free vibration analyses of multiple delaminated angle-ply composite conical shells – A finite element approach

In this paper, the finite element method is employed to investigate the effects of delamination on free vibration characteristics of graphite–epoxy pretwisted shallow angle-ply composite conical shells. The generalized dynamic equilibrium equation is derived from Lagrange’s equation of motion neglecting Coriolis effect for moderate rotational speeds. The theoretical formulation is based on the Mindlin’s theory and the multi-point constraint algorithm is considered for an eight noded isoparametric plate bending element. The standard eigenvalue problem is solved by applying the QR iteration algorithm. The mode shapes are also depicted for a typical laminate configuration. Non-dimensional natural frequencies obtained are the first known results for the type of analyses carried out here.     

Processing and Properties of Eu3+:LiTaO3 TransparentGlass–Ceramic Nanocomposites

We report here the processing and properties of transparent glass and glass–ceramic nanocomposites in the Li₂O–Ta₂O₅–SiO₂–Al₂O₃ system in the presence of Eu₂O₃ as luminescent probe. The formation of the LiTaO₃ crystal phase, the crystallite size, and the morphology with the progression of heat treatment have been examined by X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transformed infrared reflectance spectroscopy measurements. The crystallite sizes obtained from XRD and TEM are found to increase with heat-treatment time and vary in the range of 2–20 nm. The measured photoluminescence spectra exhibit emission transitions of ⁵D_0,1→⁷F _j ( j =0, 1, 2, 3, and 4) of Eu³⁺ ions. From the nature of the emission transitions, the site symmetry in the vicinity of Eu³⁺ ions has been found to be near C_3v in the glass–ceramic nanocomposites. An inverse correlation has been observed between the asymmetric ratio ( I _ED/ I _MD) of Eu³⁺ ions and the dielectric constant (ɛ_r), with an increase in the heat-treatment time of glass, which is caused by the dipole–dipole interaction.     

A study of molecular weight regulation in polyethylene by titanium diolate catalysts

A series of homogeneous titanium(IV) complexes derived from cyclohexanediol were synthesized and characterized. These catalysts, formulated as [Ti–(O^∩O)(OR)₂], [Ti–(O^∩O)OPrⁱCl] and [Ti–(O^∩O)₂], were found to be highly active in the polymerization of ethylene at high temperature in combination with ethylaluminium sesquichloride (Et₃Al₂Cl₃, EASC) as co‐catalyst. The resultant polyethylene had a low polydispersity index indicating the formation of single‐site catalytic species with molecular weight in the range 639–1036 g mol^?1 which was analysed using ¹H NMR spectroscopy and found to be linear, suggesting that a chain transfer to the aluminium of EASC occurs. © 2013 Society of Chemical Industry     

Time dependent response of low velocity impact induced composite conical shells under multiple delamination

This paper presents the time dependent response of multiple delaminated angle-ply composite pretwisted conical shells subjected to low velocity normal impact. The finite element formulation is based on Mindlin’s theory incorporating rotary inertia and effects of transverse shear deformation. An eight-noded isoparametric plate bending element is employed to satisfy the compatibility of deformation and equilibrium of resultant forces and moments at the delamination crack front. A multipoint constraint algorithm is incorporated which leads to asymmetric stiffness matrices. The modified Hertzian contact law which accounts for permanent indentation is utilized to compute the contact force, and the time dependent equations are solved by Newmark’s time integration algorithm. Parametric studies are conducted with respect to triggering parameters like laminate configuration, location of delamination, angle of twist, velocity of impactor, and impactor’s displacement for centrally impacted shells.     

Acetone and ethanol sensing characteristics of magnesium zinc ferrite nano-particulate chemi-resistive sensor

In the present work, acetone and ethanol sensing characteristics of wet chemically prepared magnesium zinc ferrite (MZFO) nano-particles have been investigated. X-ray diffraction and electron microscopy studies are carried out to know the phase formation behaviour and microstructure evolution of the synthesized particles. The gas sensing characteristics (response %, response time, recovery time, etc.) are estimated by varying the operating temperature of the sensor and concentrations of the test vapours. It is observed that the nanocrystalline MZFO-based sensor is more sensitive to acetone than ethanol. In addition, the sensor can detect even 10 ppm of acetone and ethanol vapours. The excellent repeatability of the sensing performances is verified by switching the sensor back and forth between air and test vapours.     

Polyaniline‐grafted polyurethane coatings for corrosion protection of mild steel surfaces

We report the superior corrosion‐resistant properties of conducting polyurethane networks of polyaniline (PANI), poly‐m‐aminophenol (PmAP), and poly‐o‐anisidine (PoA) coated on mild steel panels. These networks were prepared by blending conducting polyanilines with isocyanate‐containing prepolyurethanes. Free‐standing polyurethane films were obtained after a moisture cure for several days to ensure complete reaction of the excess isocyanate. The films were electrochemically active with conductivity in the range of 10^?2 to 10^?3 S/cm. The solution blends and formed films were characterized by infrared, ultraviolet, thermogravimetric analysis, and differential scanning calorimetry. Electrochemical corrosion studies of the coated films on mild steel panels showed excellent corrosion protection in the following order: PU‐PANI > PU‐PmAP > PU‐PoA. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45806.     

A Game Theory Based Multi Layered Intrusion Detection Framework for Wireless Sensor Networks

Most of the existing intrusion detection frameworks proposed for wireless sensor networks (WSNs) are computation and energy intensive, which adversely affect the overall lifetime of the WSNs. In addition, some of these frameworks generate a significant volume of IDS traffic, which can cause congestion in bandwidth constrained WSNs. In this paper, we aim to address these issues by proposing a game theory based multi layered intrusion detection framework for WSNs. The proposed framework uses a combination of specification rules and a lightweight neural network based anomaly detection module to identify the malicious sensor nodes. Additionally, the framework models the interaction between the IDS and the sensor node being monitored as a two player non-cooperative Bayesian game. This allows the IDS to adopt probabilistic monitoring strategies based on the Bayesian Nash Equilibrium of the game and thereby, reduce the volume of IDS traffic introduced into the sensor network. The framework also proposes two different reputation update and expulsion mechanisms to enforce cooperation and discourage malicious behavior among monitoring nodes. These mechanisms are based on two different methodologies namely, Shapley Value and Vickery–Clark–Grooves (VCG) mechanism. The complexity analysis of the proposed reputation update and expulsion mechanisms have been carried out and are shown to be linear in terms of the input sizes of the mechanisms. Simulation results show that the proposed framework achieves higher accuracy and detection rate across wide range of attacks, while at the same time minimizes the overall energy consumption and volume of IDS traffic in the WSN.     

Reversible addition fragmentation chain transfer-mediated bioconjugated amphiphilic graft-block copolymer using dextran,poly (N-isopropylacrylamide), and poly (vinyl acetate)

RAFT polymerization is a well-known approach to develop amphiphilic copolymer with less heterogeneity and narrow dispersity. Herein, an amphiphilic bioconjugated graft-block copolymer (Dextran-g-(PNIPAAm-b-PVAc)) using dextran, N-isopropyl acrylamide and vinyl acetate has been developed through RAFT polymerization. The chain length of the PVAc block has been varied to obtain the copolymers with different hydrophobic segments. The lower critical solution temperature, critical micelle concentration, and micellar stability of the synthesized copolymers have been studied in details. in-vitro cytotoxicity, as well as the in vitro release of a hydrophobic drug have been carried out to explore its suitability in the field of biomedical science. The synthesized copolymer has been found to have controlled molecular weight with narrow dispersity. It is cytocompatible toward Human cervical cancer cell line cell lines, can efficiently load a hydrophobic drug-norfloxacin, and subsequently, release in the sustained manner as manifested from in vitro release study.