Self Assembly and Properties of C:WO3 Nano-Platelets and C:VO2/V2O5 Triangular Capsules Produced by Laser Solution Photolysis

Laser photolysis of WCl₆ in ethanol and a specific mixture of V₂O₅ and VCl₃ in ethanol lead to carbon modified vanadium and tungsten oxides with interesting properties. The presence of graphene’s aromatic rings (from the vibrational frequency of 1,600 cm⁻¹) together with C–C bonding of carbon (from the Raman shift of 1,124 cm⁻¹) present unique optical, vibrational, electronic and structural properties of the intended tungsten trioxide and vanadium dioxide materials. The morphology of these samples shows nano-platelets in WO _x samples and, in VO _x samples, encapsulated spherical quantum dots in conjunction with fullerenes of VO _x . Conductivity studies revealed that the VO₂/V₂O₅ nanostructures are more sensitive to Cl than to the presence of ethanol, whereas the C:WO₃ nano-platelets are more sensitive to ethanol than atomic C.     

Effective quality-controlled SPIHT-based ECG coding strategy under noise environments

An effective quality-controlled set partitioning in hierarchical trees (SPIHT)-based ECG coding strategy under noise environments is proposed using a wavelet-energy based weighted percentage root mean square difference (WEWPRD_s) criterion. This criterion is subjectively meaningful and leads to a better measure of rate-distortion (R-D) performance. Experiments on several noisy records from the MIT-BIH arrhythmia (mita) database show that the proposed strategy outperforms PRD and wavelet-based weighted PRD_ws)(WWPRD_s)) measurement- criteria-based strategies.     

Mobility Aware Clustering Scheme with Bayesian-Evidence Trust Management for Public Key Infrastructure in Ad Hoc Networks

Wireless Personal Communications - The autonomous nodes in Mobile Ad Hoc Networks (MANETs) are vulnerable to attacks ranging from passive to active, due to the dynamic mobility paradigm. Earlier,...     

An Improved Steganographic Scheme Using the Contour Principle to Ensure the Privacy of Medical Data on Digital Images

With the improvement of current online communication schemes, it is now possible to successfully distribute and transport secured digital Content via the communication channel at a faster transmission rate. Traditional steganography and cryptography concepts are used to achieve the goal of concealing secret Content on a media and encrypting it before transmission. Both of the techniques mentioned above aid in the confidentiality of feature content. The proposed approach concerns secret content embodiment in selected pixels on digital image layers such as Red, Green, and Blue. The private Content originated from a medical client and was forwarded to a medical practitioner on the server end through the internet. The K-Means clustering principle uses the contouring approach to frame the pixel clusters on the image layers. The content embodiment procedure is performed on the selected pixel groups of all layers of the image using the Least Significant Bit (LSB) substitution technique to build the secret Content embedded image known as the stego image, which is subsequently transmitted across the internet medium to the server end. The experimental results are computed using the inputs from “Open-Access Medical Image Repositories (aylward.org)” and demonstrate the scheme’s impudence as the Content concealing procedure progresses.     

A Self‐Branched Lamination of Hierarchical Patronite Nanoarchitectures on Carbon Fiber Cloth as Novel Electrode for Ionic Liquid Electrolyte‐Based High Energy Density Supercapacitors

The developments of rationally designed binder‐free metal chalcogenides decorated flexible electrodes are of paramount importance for advanced energy storage devices. Herein, binder‐free patronite (VS₄) flower‐like nanostructures are facilely fabricated on a carbon cloth (CC) using a facile hydrothermal method for high‐performance supercapacitors. The growth density and morphology of VS₄ nanostructures on CC are also controlled by varying the concentrations of vanadium and sulfur sources along with the complexing agent in the growth solution. The optimal electrode with an appropriate growth concentration (VS₄‐CC@VS‐3) demonstrates a considerable pseudocapacitance performance in the ionic liquid (IL) electrolyte (1‐ethyl‐3‐methylimidazolium trifluoromethanesulfonate), with a high operating potential of 2 V. Utilizing VS₄‐CC@VS‐3 as both positive and negative electrodes, the IL‐based symmetric supercapacitor is assembled, which demonstrates a high areal capacitance of 536 mF cm^?2 (206 F g^?1) and excellent cycling durability (93%) with superior energy and power densities of 74.4 µWh cm^?2 (28.6 Wh kg^?1) and 10154 µW cm^?2 (9340 W kg^?1), respectively. As for the high energy storage performance, the device stably energizes various portable electronic applications for a long time, which make the fabricated composite material open up news for the fabrication of fabrics supported binder‐free chalcogenides for high‐performance energy storage devices.     

Multispectral and Circular Polarization-Sensitive Carbon Dot-Polydiacetylene Capacitive Photodetector (Small 31/2023)

Multispectral photodetectors (MSPs) and circularly polarized light (CPL) sensors are important in opto-electronics, photonics, and imaging. A capacitive photodetector consisting of an interdigitated electrode coated with carbon dot/anthraquinone-polydiacetylene is constructed. Photoexcitation of the carbon dots induces transient electron transfer to the anthraquinone moieties, and concomitant change in the film dielectric constant and recorded capacitance. This unique photodetection mechanism furnishes wavelength selectivity that is solely determined by the absorbance of the carbon dots incorporated in the anthraquinone-polydiacetylene matrix. Accordingly, employing an array of polymerized-anthraquinone photodetector films comprising carbon dots (C-dots) exhibiting different excitation wavelengths yielded optical “capacitive fingerprints” in a broad spectral range (350–650 nm). Furthermore, circular light polarization selectivity is achieved through chiral polymerization of the polydiacetylene framework. The carbon dot/anthraquinone-polydiacetylene capacitive photodetector features rapid photo-response, high fidelity, and recyclability as the redox reactions of anthraquinone are fully reversible. The carbon dot/anthraquinone-polydiacetylene platform is inexpensive, easy to fabricate, and consists of environmentally friendly materials.     

Microwave combustion synthesis,magneto-optical and electrochemical properties of NiMoO4 nanoparticles for supercapacitor application

Nickel molybdate (NiMoO₄) nanoparticles (NPs) were synthesized by a simplistic one-pot microwave combustion method using urea as the fuel. The produced NPs have been examined by powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR) analysis, scanning electron microscope (SEM), energy dispersive X-ray (EDX), high-resolution transmission electron microscopy (HR-TEM) analysis. Further, optical and electronic properties were determined by UV-Visible and Photoluminescence (PL) analysis, respectively. The magnetic performance of the NiMoO₄ NPs was investigated by vibrating sample magnetometer (VSM) and the surface chemical composition was identified by X-ray photoelectron spectroscopy (XPS). The electrochemical activities of the NiMoO₄ NPs were studied by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge/discharge (GCD) analysis. From the results, the CV curves indicated the occurrence of redox couples and besides with the EIS data (Nyquist plot), confirmed the supercapacitor nature of the synthesized NiMoO₄. The prepared NiMoO₄ exhibits a high specific capacitance and rateability. This electrode grants a high specific capacitance of 450?F?g^?1 at 2?mA?cm^?2 and the well permanency with a cycling proficiency of 94% after 1000 cycles. These results clearly showed that the synthesized NiMoO₄ NPs have potential application for the forthcoming flexible and lightweight energy storage.     

Mixed convection characteristics in lid-driven cavity containing heated triangular block

This research work numerically analyzes 2D,steady state,mixed convective heat transfer for Newtonian fluids in lid driven square enclosure with centered triangular block (blockage-10％ or 30％) maintained either at the constant wall temperature or constant heat flux thermal conditions.The fluid flow in the enclosure is initiated by top moving wall in +x-direction,while all other walls are stationary.The top and bottom walls are thermally insulated.In particular,the goveming field equations are solved for range of governing parameters such as,Reynolds number (1-1000),Prandtl number (1-100),and Grashof number (0-105).It is observed that the increase in inertial force enhances the heat transfer rate up to certain Reynolds number range (80-200),later deterioration of heat transfer rate is observed.Such behavior is found to be true for lower blockage (10％).Finally,functional dependence of average Nusselt number values with flow governing dimensionless parameters is developed and presented for its possible utilization in engineering and design purpose.     

Completely biodegradable banana fiber-wheat gluten composites for dielectric applications

Biodegradable composites with desirable dielectric constants were obtained using banana fibers as reinforcement and wheat gluten as matrix. Dielectric materials play a critical role in many integrated circuits and microelectronics. Most dielectric materials are made from ceramics and synthetic polymers which are heavy, expensive, have limited range of dielectric values and also not biodegradable. Unlike previous reports that have developed partially biodegradable composites for dielectric applications, we have used protein and a natural fiber as matrix and reinforcement, respectively resulting in composites that are completely biodegradable. In addition, the thickness of the composites was varied which creates air gaps and influences the dielectric properties. Mechanical and electrical properties of the composites were studied at ambient and higher temperatures. Flexural and tensile properties were significantly influenced by the ratio of matrix and reinforcement and thickness of the composites. Dielectric values obtained ranged from 2 to 49 depending on the frequency. Dielectric constant, dielectric loss and dissipation factor decreased whereas conductivity increased with increasing frequency for all the samples. Biodegradable composites suitable for various electronic applications can be obtained with desired dielectric values by varying the composite fabrication conditions.