Influence of different conducting substrates on magnetic properties of electrodeposited Ni–Fe thin films

Electrodeposition of Ni–Fe soft magnetic alloy on copper and stainless steel substrates was performed in chloride bath. The deposition parameters such as current density, pH, temperature and deposition time have been investigated. From the investigation the optimized deposition parameters were current density 3.5 mA/cm², pH 3, temperature 30 °C and deposition time 15 min. The Ni–Fe magnetic alloys deposited on copper and stainless steel substrates under optimized deposition parameters are subjected to various characterizations. The structural and surface morphology of the Ni–Fe films were detected by using X-ray diffractogram (XRD) and scanning electron microscope (SEM) respectively. The constituents in the films were determined by energy dispersive X-ray spectroscopy (EDAX) technique. The magnetic properties such as the coercivity (H_c) and saturation magnetization of the films were studied with the help of vibrating sample magnetometer (VSM). From the magnetic studies it is concluded that the grain size are create a considerable impact on magnetic behavior of the films on both the substrates. The films prepared on stainless steel substrate of 0.1 M concentration at optimized deposition parameters exhibits higher coercivity (5010 Oe) which seems to be ideal for magnetic sensor applications.     

Efficient Resource Allocation in Fog Computing Using QTCS Model

Infrastructure of fog is a complex system due to the large number of heterogeneous resources that need to be shared. The embedded devices deployed with the Internet of Things (IoT) technology have increased since the past few years, and these devices generate huge amount of data. The devices in IoT can be remotely connected and might be placed in different locations which add to the network delay. Real time applications require high bandwidth with reduced latency to ensure Quality of Service (QoS). To achieve this, fog computing plays a vital role in processing the request locally with the nearest available resources by reduced latency. One of the major issues to focus on in a fog service is managing and allocating resources. Queuing theory is one of the most popular mechanisms for task allocation. In this work, an efficient model is designed to improve QoS with the efficacy of resource allocation based on a Queuing Theory based Cuckoo Search (QTCS) model which will optimize the overall resource management process.     

Dissipativity and passivity analysis of Markovian jump impulsive neural networks with time delays

This paper discusses the issue of dissipativity and passivity analysis for a class of impulsive neural networks with both Markovian jump parameters and mixed time delays. The jumping parameters are modelled as a continuous-time discrete-state Markov chain. Based on a multiple integral inequality technique, a novel delay-dependent dissipativity criterion is established via a suitable Lyapunov functional involving the multiple integral terms. The proposed dissipativity and passivity conditions for the impulsive neural networks are represented by means of linear matrix inequalities. Finally, three numerical examples are given to show the effectiveness of the proposed criteria.     

Experimental investigation on degradation of heat transfer properties of a black chromium-coated aluminium surface solar collector tube

ABSTRACT

In our earlier research, we have studied the surface radiation property degradation of the solar collector receiver tube material [Logesh, K., R. Ganesh, I. Saran Raj, V. Ramesh, and B. Tharun Raj. 2017. “Experimental Investigation on Radiation Heat Transfer Properties Degradation of Aluminium Solar Receiver Tube Material.” International Journal of Ambient Energy. doi:10.1080/01430750.2017.1335230]. In this study, the examination is expanded to degradation property of the selective surface, black chromium-coated aluminium material. Black chrome is mainly used for its high corrosion resistance. The selective surface has been examined for its emissivity (ε) and absorptivity (α) changes due to its sunlight exposure at elevated temperatures. The exposure duration ranges from 240 to 960?h. In the selected range of exposure, the properties are measured in four intervals. The emissivity (ε) is found to decrease, whereas the absorptivity (α) gets increased for coated than the uncoated surfaces for the same duration of exposure. The examination is also carried out to find the nature of the heat transfer properties determined by its temperature. For every duration of exposure, the properties are measured at 10 temperature intervals.     

Bionanofactories for Green Synthesis of Silver Nanoparticles: Toward Antimicrobial Applications

Among the various types of nanoparticles and their strategy for synthesis, the green synthesis of silver nanoparticles has gained much attention in the biomedical, cellular imaging, cosmetics, drug delivery, food, and agrochemical industries due to their unique physicochemical and biological properties. The green synthesis strategies incorporate the use of plant extracts, living organisms, or biomolecules as bioreducing and biocapping agents, also known as bionanofactories for the synthesis of nanoparticles. The use of green chemistry is ecofriendly, biocompatible, nontoxic, and cost-effective. We shed light on the recent advances in green synthesis and physicochemical properties of green silver nanoparticles by considering the outcomes from recent studies applying SEM, TEM, AFM, UV/Vis spectrophotometry, FTIR, and XRD techniques. Furthermore, we cover the antibacterial, antifungal, and antiparasitic activities of silver nanoparticles.     

Finite element modeling of environmental effects on rigid pavement deformation

In this study, finite element (FE)-based primary pavement response models are employed for investigating the early-age deformation characteristics of jointed plain concrete pavements (JPCP) under environmental effects. The FE-based ISLAB (two-and-one-half-dimensional) and EverFE (three-dimensional) software were used to conduct the response analysis. Sensitivity analyses of input parameters used in ISLAB and EverFE were conducted based on field and laboratory test data collected from instrumented pavements on highway US-34 near Burlington, Iowa. Based on the combination of input parameters and equivalent temperatures established from preliminary studies, FE analyses were performed and compared with the field measurements. Comparisons between field measured and computed deformations showed that both FE programs could produce reasonably accurate estimates of actual slab deformations due to environmental effects using the equivalent temperature difference concept.     

Scale effects on buckling analysis of orthotropic nanoplates based on nonlocal two-variable refined plate theory

This article presents the buckling analysis of orthotropic nanoplates such as graphene using the two-variable refined plate theory and nonlocal small-scale effects. The two-variable refined plate theory takes account of transverse shear effects and parabolic distribution of the transverse shear strains through the thickness of the plate, hence it is unnecessary to use shear correction factors. Nonlocal governing equations of motion for the monolayer graphene are derived from the principle of virtual displacements. The closed-form solution for buckling load of a simply supported rectangular orthotropic nanoplate subjected to in-plane loading has been obtained by using the Navier’s method. Numerical results obtained by the present theory are compared with first-order shear deformation theory for various shear correction factors. It has been proven that the nondimensional buckling load of the orthotropic nanoplate is always smaller than that of the isotropic nanoplate. It is also shown that small-scale effects contribute significantly to the mechanical behavior of orthotropic graphene sheets and cannot be neglected. Further, buckling load decreases with the increase of the nonlocal scale parameter value. The effects of the mode number, compression ratio and aspect ratio on the buckling load of the orthotropic nanoplate are also captured and discussed in detail. The results presented in this work may provide useful guidance for design and development of orthotropic graphene based nanodevices that make use of the buckling properties of orthotropic nanoplates.     

Studies on the photochemical deposition (PCD) of II–VI compound semiconductor thin films of ZnS from aqueous solution

Zinc sulphide (ZnS) thin films were depositedon Indium oxide coaled glass substrates by Photo Chemical Deposition (PCD) with starting precursor of Zinc sulphate and sodium thiosulphate as a source material for Zn and S respectively. In addition the pH was varied (3 to 8) using sulphuric acid by adding up in the precursor. Later the ZnS thin films were annealed at 500°C and it was found that crystalline structure was improved. Zinc blende crystalline structure was observed on the thin films using X-ray diffractometer (XRD). The morphological behavior was observed using Scanning electron microscope (SEM) and it reveals that the size of the grain increases after annealing at 500°C. UV-spectrometer was used to analyze the aqueous solution optical behavior before and after deposition. The average thickness of thin film was estimated as ～1.02 micron measured by stylus profilometer method.     

Effect of glycerol and short sisal fibers on the viscoelastic behavior of wheat flour based thermoplastic

Wheat flour based thermoplastic having glycerol content (20%, 23%, 25%, 30% and 35% w/w) were fabricated using extrusion followed by compression molding. Dynamic mechanical analysis (DMA) has been done with reference to the amount of glycerol, sisal fiber loading, frequency and temperature. Two transitions peaks were observed for the, matrix, one at low temperature, due to the molecular dynamics associated to glycerol rich phase, and another at high temperature attributed to the molecular relaxation of starch rich phase. By changing the amount of glycerol, it has been observed that, at all temperature ranges, a plasticization effect which concerns mainly in the starch rich phase. Introduction of sisal fiber (up to 10% w/w) increases the storage modulus of the thermoplastic matrix. The peak height of damping curves (tan δ) was lowered as the fiber content. The activation energy was calculated from the maximum temperature (T_max) of damping curves.     

Low-cost plastic plasmonic substrates for operation in aqueous environments

We report a novel design of a multilayer stack to attain surface-plasmon-coupled emission (SPCE) enhancements in liquid medium. Variation in thickness of the multilayer affects the position and depth of resonance plasmon dips. Numerical investigation resulted in an optimal stack configuration that supports long-range surface plasmons. SPCE substrates were prepared on plain BK7 glass and Teflon-AF coated polycarbonate (PC-T) substrates by modifying their surface functionalities using plasma etching. The changes in refractive indices due to the presence of the fluoropolymer layer help reduce the SPCE exit angle from α = 75° (plain BK7) to α = 60° (PC-T) in water without requiring specialized optics.