Selective Coating of SnS on the Bio‐Inspired Moth‐Eye Patterned PEDOT:PSS Polymer Films

A new strategy for the selective coating of tin sulfide (SnS) on the surface of moth‐eye patterned (MEP) conducting polymer film is studied by considering the optical properties of the antireflective moth‐eye pattern and flexibility of polymer films. The semiconductor SnS is selectively coated on the surface of MEP microdomes of poly(3,4‐ethylenedioxythiophene) poly(styrene‐sulfonate) (PEDOT:PSS) film. The SnS coated MEP film is obtained by using pore selectively SnS thin layer functionalized polystyrene honeycomb‐patterned porous (HCP) film as a template. Aqueous PEDOT:PSS solution is poured on the SnS functionalized HCP films and detached for the fabrication of SnS coated MEP films. The films show a satisfactory photo‐responsive property under solar stimulated light illumination due to the antireflective MEP structure of PEDOT film and homogenous SnS coating on the surface of the conducting polymer.     

Preliminary<Emphasis Type="Italic">in vitro</Emphasis> and<Emphasis Type="Italic">in vivo</Emphasis> characterizations of a sol-gel derived bioactive glass-ceramic system

This study investigates quantitatively and qualitatively the sol-gel derived bioactive glass-ceramic system (BGS)—apatite-wollastonite (AW) type granules in the size range of 0.5–1 mm, as an effective graft material for bone augmentation and restoration. Scanning electron micrographs (SEM) of the sintered granules revealed the rough material surface with micropores in the range 10–30 μm. X-ray diffraction (XRD) pattern of the granules revealed the presence of crystalline phases of the hydroxyapatite and wollastonite, and the functional groups of the silicate and phosphates were identified by Fourier transform infrared spectroscopy (FT-IR). Thein vitro cell culture studies with L929 mouse fibroblast cell line showed very few cells adhered on the BGS disc after 24 h. This could be due to the highly reactive surface of the disc concomitant with the crystallization but not due to the cytotoxicity of the material, since the cellular viability (MTT assay) with the material was 80‰ Cytotoxicity and cytocompatibility studies proved that the material was non-toxic and biocompatible. After 12 weeks of implantation of the BGS granules in the tibia bone of New Zealand white rabbits, the granules were found to be well osteointegrated, as observed in the radiographs. Angiogram with barium sulphate and Indian ink after 12 weeks showed the presence of microcapillaries in the vicinity of the implant site implicating high vascularity. Gross observation of the implant site did not show any inflammation or necrosis. SEM of the implanted site after 24 weeks revealed good osteointegration of the material with the newly formed bone and host bone. New bone was also observed within the material, which was degrading. Histological evaluation of the bone healing with the BGS granules in the tibial defect at all time intervals was without inflammation or fibrous tissue encapsulation. After 2 weeks the new bone was observed as a trabeculae network around the granules, and by 6 weeks the defect was completely closed with immature woven bone. By 12 weeks mature woven bone was observed, and new immature woven bone was seen within the cracks of the granules. After 24 weeks the defect was completely healed with lamellar bone and the size of the granules decreased. Histomorphometrically the area percentage of new bone formed was 67.77% after 12 weeks and 63.37% after 24 weeks. Less bone formation after 24 weeks was due to an increased implant surface area contributed by the material degradation and active bone remodeling. The osteostimulative and osteoconductive potential of the BGS granules was established by tetracycline labelling of the mineralizing areas by 2 and 6 weeks. This sol-gel derived BGS granules proved to be bioactive and resorbable which in turn encouraged active bone formation.     

Numerical analysis of electromagnetic scattering by electricallylarge objects using spatial decomposition technique

Apparent computational difficulties with the direct integral equation and method of moments have prompted an alternative numerical solution procedure based on the spatial decomposition technique. Using rigorous electromagnetic equivalence, the spatial decomposition technique virtually divides an electrically large object into a multiplicity of subzones. It permits the maximum size of the method of moments system matrix that needs to be inverted to be strictly limited, regardless of the electrical size of the large scattering object being modeled. The requirement on the computer resources is O(N ), where N is the number of spatial subzones and each subzone is electrically small, spanning on the order of a few wavelengths. Numerical examples are reported along with comparative data and relative error estimation to expose the applicability and limitations of the spatial decomposition technique for the two-dimensional scattering study of electrically large conducting and dielectric objects     

FDTD analysis of electromagnetic wave radiation from systemscontaining horn antennas

The application of the finite-difference time-domain (FDTD) method to various radiating structures is considered. These structures include two- and three-dimensional waveguides, flared horns, a two-dimensional parabolic reflector, and a two-dimensional hyperthermia application. Numerical results for the horns, waveguides, and parabolic reflectors are compared with results from using the method of moments (MM). The results for the hyperthermia application are shown as extensions of the previously validated models. This new application of the FDTD method is shown to be useful when other numerical or analytic methods cannot be applied     

IEVCA: An efficient image encryption technique for IoT applications using 2-D Von-Neumann cellular automata

Multimedia Tools and Applications - Present era is marked by exponential growth in transfer of multimedia data through internet. Most of the Internet-of-Things(IoT) applications send images to...     

Calculation and experimental validation of induced currents on coupled wires in an arbitrary shaped cavity

An efficient numerical technique is presented for the calculation of induced electric currents on coupled wires and multiconductor bundles placed in an arbitrary shaped cavity and excited by an external incident plane wave. The method is based upon the finite-difference time-domain (FD-TD) formulation. The concept of equivalent radius is used to replace wire bundles with single wires in the FD-TD model. Then, the radius of the equivalent wire is accounted by a modified FD-TD time-stepping expression (based on a Faraday's law contour-path formulation) for the looping magnetic fields adjacent to the wire. FD-TD computed fields at a virtual surface fully enclosing the equivalent wire are then obtained, permitting calculation of the currents on the wires of the original bundle using a standard electric field integral equation (EFIE). Substantial analytical and experimental validations are reported for both time-harmonic and broad-band excitations of wires in free space and in a high-Qmetal cavity.     

Electromagnetic scattering by arbitrary shaped three-dimensional homogeneous lossy dielectric objects

The recent development and extension of the method of moments technique for analyzing electromagnetic scattering by arbitrary shaped three-dimensional homogeneous lossy dielectric objects is presented based on the combined field integral equations. The surfaces of the homogeneous three-dimensional arbitrary geometrical shapes are modeled using surface triangular patches, similar to the case of arbitrary shaped conducting objects. Further, the development and extensions required to treat efficiently three-dimensional lossy dielectric objects are reported. Numerical results and their comparisons are also presented for two canonical dielectric scatterers-a sphere and a finite circular cylinder.     

Effect of Fiber Bridging Stress on the Fracture Resistance of Silicon-Carbide-Fiber/Zircon Composites

The room-temperature fracture-resistance behavior ( R -curve) of unidirectional silicon-carbide-fiber-reinforced zircon-matrix composites has been studied experimentally and numerically. The composites showed strong rising R -curve behavior from experimental results that used in situ crack-length measurements taken via optical microscopy as well as the compliance method. A numerical calculation, based on the available models, then was performed to determine the bridging-stress function from the experimental R -curve. In addition, the effect of the residual stress and constituent properties on the bridging-stress function also has been considered in the numerical calculations. These results have indicated that the bridging-stress function, which controls the fracture resistance of ceramic composites, can be obtained from the carefully measured R -curve.     

Options and Opportunities for Energy Management in Malaysian Grid Systems—Putrajaya as a Case Study

This paper presents an opportunity for energy management with an integrated photovoltaic and wind farm for the energy and economic aspects of the commercial area located in Putrajaya. The energy economy accession conforming to the wind speed, temperature, solar irradiation, and energy consumption on a daily basis is taken into consideration. Design analysis is done through the industry standard numerical tool. From the result analysis, the recommended ratio of renewable share minimizing stress to the electric grid is proposed. According to the solutions obtained from the numerical design tool, photovoltaic is recommended to be more energy efficient and economically viable in comparison of the fully crowded wind farm. From the proposed solutions, the photovoltaic is able to provide 51% of the energy consumed and it costs RM 0.365 per kW/h.     

Reversible change of wettability in poly(ɛ-caprolactone/azobenzene) honeycomb-patterned films by UV and visible light illumination

Polymer Bulletin - A new type of photosensitive poly(?-caprolactone) (PCL) composites containing 4-dimethylamino-4′-(6-hydroxy hexyloxy) azobenzene (Azo) was synthesized by in situ...