Microstructural and Magnetic Features of SrFe<Subscript>12</Subscript><Emphasis Type="Italic">O</Emphasis><Subscript>19</Subscript> Materials Synthesized from Different Fuels by Sol-Gel Auto-Combustion Method

The nanocrystalline SrFe₁₂ O ₁₉ materials were prepared by a sol-gel auto-combustion method using different fuels such as citric acid, dextrose, aniline, and hexamine. The combustion product obtained from all the fuels except from that of aniline show a single phase of SrFe₁₂ O ₁₉ materials upon annealing at 1000 ^°C/2 h. The combustion product obtained from aniline as fuel shows SrFe₁₂ O ₁₉ as the main phase with α-Fe₂ O ₃ as impurity. No notable change in lattice parameters is observed due to variation in fuels for SrFe₁₂ O ₁₉ materials. With a little change in the NIR relative reflectance (72–85 %) on fuels, the different SrFe₁₂ O ₁₉ materials display high NIR reflectance in the wavelength range, 1500–2500 nm. The photoluminescence emission spectra of SrFe₁₂ O ₁₉ materials reveal a broad emission peak at ～350 nm which is reminiscent to the Ba-based hexaferrite, BaFe₁₂ O ₁₉. The FESEM images expose quite dissimilar morphology for the various fuels used in the synthesis of SrFe₁₂ O ₁₉ materials. Hysteresis loops for all the nanocrystalline SrFe₁₂ O ₁₉ materials observed under the applied field of ±1.5 T at room temperature exhibit hard ferromagnetic property. The SrFe₁₂ O ₁₉ materials produced from glycine and aniline as fuels exhibit highest and lowest M _s values of 61.3 and 50.5 emu/g, respectively.     

Annealing Effects in (Hg,Cr)Sr2CuO4+δ: Transport and X-Ray Absorption Studies

Superconducting (Hg_1–x Cr _x )Sr₂CuO₄₊, x 0.36, samples of 1201-type, synthesized in partial vacuum, show T _c ^onset of 58 K, T _c (R = 0) 52 K. It is found that T _c is not affected by the subsequent Ar or O₂ annealing treatment. Remarkably, the annealed samples show significant improvement in the diamagnetic signal. Hg L₃-edge measurements on 1201 samples show divalent state of mercury. The Cu K-edge spectra for the samples, after taking due account of the impurity phases, show noticeable modifications in the split main peak features on Ar or O₂ annealing, suggesting changes in the crystal field asymmetry. In the superconducting (SC) samples, a weak but distinct signature of Cu¹⁺ is seen. The Cu¹⁺ feature is absent in all the non-SC 1201 samples as well as in the impurity phase SrCuO₂ and Sr₂CuO₃ samples. An attempt is made to explain the observed Cu¹⁺ feature in SC (Hg,Cr)-1201 in the light of the available reports.     

Superconductivity and Magnetism in R 2CaBa2Cu5O z (R=La, Pr, Nd and Eu)

A series of compounds R ₂CaBa₂Cu₅O _z (R=La, Pr, Nd and Eu) have been synthesized by conventional solid state reaction and characterized for their structural, superconducting and magnetic properties. All compounds crystallize with the tetragonal LaBa₂Cu₃O _z type structure, space group P4/mmm. Among the four compounds studied here, R=La, Nd and Eu are superconductors with superconducting transition temperatures (T _c ^R=0) of 72, 40 and 55 K, respectively. On the other hand, neither superconductivity nor magnetic ordering is seen for R=Pr down to 3 K. The effect of the magnetic field on the susceptibility and (magneto) resistance for the superconducting samples has been investigated. The superconductivity of compounds with magnetic rare-earth ions Nd and Eu exhibit a profound influence of the magnetic field, whereas the application of the magnetic field has a limited effect on the La compound. The Pr compound is paramagnetic and does not exhibit magnetic ordering either.     

Visible light irradiated photocatalytic and magnetic properties of Fe-doped SnS<Subscript>2</Subscript> nanopowders

Fe-doped SnS₂ (SnS₂:Fe) nanopowders were synthesized by cost effective chemical method and characterized by thermo gravimetric-differential thermal analysis, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and vibrating sample magnetometer techniques. The photocatalytic activity was evaluated for the degradation of congo red dye under visible light irradiation. XRD studies indicate that both the undoped and doped SnS₂ nanopowders exhibit hexagonal crystal structure with a strong (1 0 1) preferential growth. Nanosized grains are evinced from the TEM images. XPS spectra confirmed the presence of Fe in the doped samples. Photodegradation efficiency increased with increase in Fe doping concentration and the SnS₂:Fe nanopowder with 10 wt% Fe doping concentration exhibits a maximum efficiency of 93.94% after 180 min light irradiation. Ferromagnetic ordering of pure SnS₂ improved with Fe doping. The outcome of the results indicated that Fe-doped SnS₂ nanopowders are well suited as diluted magnetic semiconductor and also can be used as an efficient photocatalyst.     

Green Computing Process and its Optimization Using Machine Learning Algorithm in Healthcare Sector

Mobile Networks and Applications - Handling the information is crucial task in healthcare sector; the data mining techniques will be right choice to address the complex problems. The hybridized...     

Concurrent optimal allocation of geometric and process tolerances based on the present worth of quality loss using evolutionary optimisation techniques

Concurrent tolerancing becomes an optimisation problem to find out the optimum allocation of the process tolerances in the given design function constraints. In traditional optimisation methods, finding out the optimum solution for this advanced tolerance design problem is complex. The proposed algorithms (elitist non-dominated sorting genetic algorithm) and differential evolution extensively do better than the previous algorithms for attaining the optimum result. The aim of this paper is to suggest a model for optimal tolerance allocation by considering both tolerance cost and the present worth of quality loss such that the total manufacturing cost/loss is minimised. The suggested model takes into account the time value of money for quality loss and product degradation over time and consists of two new parameters: the planning horizon and the product user’s discount rate. From the outcome of this study, a longer planning horizon results in an increase in both tolerance cost and quality loss; however, a larger value of discount rate gives up a decrease in both tolerance cost and quality loss. Finally, a practical example is brought into reveal the effectiveness of the suggested method.     

Hybrid BWO-IACO Algorithm for Cluster Based Routing in Wireless Sensor Networks

Wireless Sensor Network (WSN) comprises a massive number of arbitrarily placed sensor nodes that are linked wirelessly to monitor the physical parameters from the target region. As the nodes in WSN operate on inbuilt batteries, the energy depletion occurs after certain rounds of operation and thereby results in reduced network lifetime. To enhance energy efficiency and network longevity, clustering and routing techniques are commonly employed in WSN. This paper presents a novel black widow optimization (BWO) with improved ant colony optimization (IACO) algorithm (BWO-IACO) for cluster based routing in WSN. The proposed BWO-IACO algorithm involves BWO based clustering process to elect an optimal set of cluster heads (CHs). The BWO algorithm derives a fitness function (FF) using five input parameters like residual energy (RE), inter-cluster distance, intra-cluster distance, node degree (ND), and node centrality. In addition, IACO based routing process is involved for route selection in inter-cluster communication. The IACO algorithm incorporates the concepts of traditional ACO algorithm with krill herd algorithm (KHA). The IACO algorithm utilizes the energy factor to elect an optimal set of routes to BS in the network. The integration of BWO based clustering and IACO based routing techniques considerably helps to improve energy efficiency and network lifetime. The presented BWO-IACO algorithm has been simulated using MATLAB and the results are examined under varying aspects. A wide range of comparative analysis makes sure the betterment of the BWO-IACO algorithm over all the other compared techniques.     

Dynamic characterization of the thickness-tapered laminated plant fiber-reinforced polymer composite plates

Evolution of the laminated woven natural fiber fabric-reinforced polymer composite structures makes a way to the development of the non-uniform laminated composite structures in order to achieve the stiffness variation throughout the structure. An attempt is made in this work to carry out the experimental and numerical investigations on the dynamic characteristics of the thickness-tapered laminated woven jute/epoxy and woven aloe/epoxy composite plates. The governing differential equations of motion for the thickness-tapered laminated composite plate are developed using the h-p version FEM based on higher order shear deformation theory. The validation of the present finite element formulation is carried out by comparing the natural frequencies obtained using the finite element formulation with those natural frequencies determined experimentally. The developed model is further validated with the available literature works on tapered composite plate to confirm the efficiency of h-p version FEM. This work also explores the study of the vibrational characteristics of composite plates under the influence of plant fiber’s transverse isotropic material characteristics and porosity associated with plant fiber composites through the elastic constants evaluated in the author’s previous work. Also the influences of aspect ratios, ply orientations, and taper angles under various end conditions on the natural frequencies of the woven jute/epoxy composite plate are studied using the present finite element formulation. The forced vibration response of the thickness-tapered laminated woven jute/epoxy composite plate under the harmonic force excitation is carried out considering CFCF and CFFF end conditions.     

Evolutionary trajectory planning for an industrial robot

This paper presents a novel general method for computing optimal motions of an industrial robot manipulator (AdeptOne XL robot) in the presence of fixed and oscillating obstacles. The optimization model considers the nonlinear manipulator dynamics, actuator constraints, joint limits, and obstacle avoidance. The problem has 6 objective functions, 88 variables, and 21 constraints. Two evolutionary algorithms, namely, elitist non-dominated sorting genetic algorithm (NSGA-II) and multi-objective differential evolution (MODE), have been used for the optimization. Two methods (normalized weighting objective functions and average fitness factor) are used to select the best solution tradeoffs. Two multi-objective performance measures, namely solution spread measure and ratio of non-dominated individuals, are used to evaluate the Pareto optimal fronts. Two multi-objective performance measures, namely, optimizer overhead and algorithm effort, are used to find the computational effort of the optimization algorithm. The trajectories are defined by B-spline functions. The results obtained from NSGA-II and MODE are compared and analyzed.     

Detailed Physical Characterizations of Cu-rich and Ru-poor (Ru0.9Cu0.1)Sr2YCu2O7.9

The optimized nominal composition, (Ru_0.9Cu_0.1) Sr₂YCu₂O_7.9 sample, has been prepared through high-pressure and high-temperature solid-state densification method. The obtained material has been studied by X-ray (laboratory) diffraction powder technique, magnetization and detailed magneto-transport measurements. The title compound indicates bulk magneto-superconducting properties under field strengths of H=10, 100, 500 and 1000 Oe. It shows diamagnetic transition at T _d=54, 38, 20 and 8 K for H=10, 100, 500 and 1000 Oe, respectively, in the zero-field-cooled susceptibility measurements. The high-field (H=5 and 10 kOe) molar susceptibility measurements show sharp ferromagnetic transition at ∼150 K with reduced molar susceptibility values. The various field dependence of magnetization, M(H), isotherm curves recorded at constant temperatures (5, 10, 25, 50, 100 and 150 K) indicate ferromagnetic saturation, whereas the MH curves measured at 200 and 300 K conditions reveal the paramagnetic state of the compound. Though the sample showed onset transition temperature, T_c^onsetT_{mathrm{c}}^{mathrm{onset}}, at ∼34 K under different field strengths (H=0, 10, 30, 50, 70 and 90 kOe), no T_c^R=0T_{mathrm{c}}^{R=0} is seen down to 2 K. Even under relatively low applied field (ΔH=10 kOe) the title compound shows large negative magnetoresistance (MR) of about 68% at 2 K and increases with increasing the field strength up to ΔH=90 kOe (MR=77% at 2 K). This value is amazing and probably higher than other 1212 type ruthenocuprates. The title compound which shows little negative MR (about 1%) in the high temperature regions (125–300 K) is not affected much by different field strengths. Among the different fixed temperature MR(H) isotherms, the MR(H) curve measured at 5 K shows maximum negative MR of about 47% at 90 kOe compared to other four (T=50, 100, 200 and 300 K) MR(H) curves.