Physical Properties of Sn1−x Fe x O2 Powders Using Solid State Reaction

Iron-doped SnO₂ diluted magnetic semiconducting powders (Sn_1?x Fe _x O₂, x=0.00, 0.03, 0.05, 0.07, 0.10, and 0.15) were synthesized by a simple solid state reaction followed by vacuum annealing and studied the effect of Fe dopant concentrations on structural, optical, and magnetic properties of the synthesized samples. From the X-ray diffraction, it was confirmed that the samples prepared at lower dopant concentrations were tetragonal in structure whereas the samples prepared at higher dopant concentration exhibited orthorhombic SnO and Fe₂O₃ phases along with tetragonal SnO₂ structure. FT-IR spectrum has been used to confirm the formation of Sn–O bond. The optical band gap of the Sn_1?x Fe _x O₂ powders was increased from 3.6 eV to 3.7 eV with increase of dopant concentration. Raman spectroscopy measurement revealed that the broadening of the most intense Raman peak observed at 630 cm^?1 with Fe doping, conforming that the Fe ions are substituted at the Sn sites in the SnO₂ lattice. Vibrating sample magnetometer measurements confirmed that the Sn_1?x Fe _x O₂ powders were ferromagnetic at room temperature.     

Modelling and investigation of clean power wind energy systems by using UPQC

This article presents a new clean power technique for wind energy system based on Unified Power Quality Conditioner (UPQC) with usage of various Artificial Intelligent techniques (AI). Application of AI techniques such as Artificial Neural Networks, Fuzzy Logic is growing fast in the area of power electronics equipment‐based wind energy system, for instance, UPQC. A novel control scheme is developed by using different AI techniques to mitigate the balancing issues and to control the power–quality problems in UPQC and hence to provide clean power to the grid. The proposed system is composed of shunt active power filter, and the inherent proportional integral (PI) control parameters are tuned with application of PI techniques. A detailed Matlab simulation study is carried out with an application of PI techniques under sag, swell, unbalanced, and harmonic conditions. An exhaustive simulation study is carried out to investigate the application of PI technique‐based controllers and compare its performance with the conventional PI controller with its results explored. Copyright © 2016 John Wiley & Sons, Ltd.     

Production of bio-epoxide and bio-adhesive from non-edible oil

Epoxidation of Nahor oil was performed by H₂O₂ in the presence of acid catalyst at 50 °C. It was possible to obtain around 70% epoxide yield within 8 hrs of reaction. Amberlite IR 120H showed better epoxide yield compared to H₂SO₄ and Dowex 50 WX8. The performance of carboxylic acids was found to be in the order of formic acid>acetic acid>propanoic acid. The curing of epoxidized nahor oil involved using ethylenediamine (EDA) and diethylenetriamine (DETA). The adhesive property of the cured resins was tested and compared with commercially available glue. The force required to detach the cardboard joint was about 36.3 N for DETA-cured resin.     

Experimental Models of Status Epilepticus and Neuronal Injury for Evaluation of Therapeutic Interventions

This article describes current experimental models of status epilepticus (SE) and neuronal injury for use in the screening of new therapeutic agents. Epilepsy is a common neurological disorder characterized by recurrent unprovoked seizures. SE is an emergency condition associated with continuous seizures lasting more than 30 min. It causes significant mortality and morbidity. SE can cause devastating damage to the brain leading to cognitive impairment and increased risk of epilepsy. Benzodiazepines are the first-line drugs for the treatment of SE, however, many people exhibit partial or complete resistance due to a breakdown of GABA inhibition. Therefore, new drugs with neuroprotective effects against the SE-induced neuronal injury and degeneration are desirable. Animal models are used to study the pathophysiology of SE and for the discovery of newer anticonvulsants. In SE paradigms, seizures are induced in rodents by chemical agents or by electrical stimulation of brain structures. Electrical stimulation includes perforant path and self-sustaining stimulation models. Pharmacological models include kainic acid, pilocarpine, flurothyl, organophosphates and other convulsants that induce SE in rodents. Neuronal injury occurs within the initial SE episode, and animals exhibit cognitive dysfunction and spontaneous seizures several weeks after this precipitating event. Current SE models have potential applications but have some limitations. In general, the experimental SE model should be analogous to the human seizure state and it should share very similar neuropathological mechanisms. The pilocarpine and diisopropylfluorophosphate models are associated with prolonged, diazepam-insensitive seizures and neurodegeneration and therefore represent paradigms of refractory SE. Novel mechanism-based or clinically relevant models are essential to identify new therapies for SE and neuroprotective interventions.     

Learning mixture models via component-wise parameter smoothing

The task of obtaining an optimal set of parameters to fit a mixture model has many applications in science and engineering domains and is a computationally challenging problem. A novel algorithm using a convolution based smoothing approach to construct a hierarchy (or family) of smoothed log-likelihood surfaces is proposed. This approach smooths the likelihood function and applies the EM algorithm to obtain a promising solution on the smoothed surface. Using the most promising solutions as initial guesses, the EM algorithm is applied again on the original likelihood. Though the results are demonstrated using only two levels, the method can potentially be applied to any number of levels in the hierarchy. A theoretical insight demonstrates that the smoothing approach indeed reduces the overall gradient of a modified version of the likelihood surface. This optimization procedure effectively eliminates extensive searching in non-promising regions of the parameter space. Results on some benchmark datasets demonstrate significant improvements of the proposed algorithm compared to other approaches. Empirical results on the reduction in the number of local maxima and improvements in the initialization procedures are provided.     

JORDAN CANONICAL FORM SOLUTION FOR THERMALLY INDUCED DEFORMATIONS OF CROSS-PLY LAMINATED COMPOSITE BEAMS

Thermal deformations in symmetric and antisymmetric cross-ply beams are investigated. The state-space approach in conjunction with the Jordan canonical form is presented to obtain exact solutions for the thermoelastic response of cross-ply composite beams for arbitrary boundary conditions and subjected to general temperature fields. The classical, first-, second-, and third-order beam theories are used in the analysis. As a demonstrative example, deflections are computed for beams with various lamination schemes and boundary conditions undergoing linearly varying temperature through the thickness.     

Sulfur-impregnated porous carbon for removal of mercuric chloride: optimization using RSM

This study relates to optimization of process conditions for sulfur impregnation process on to a virgin steam-activated commercial carbon, with the objective of maximizing the mercuric chloride adsorption. Process optimization was performed using response surface methodology adopting Box–Behnken design. The chosen key process parameters being impregnation temperature (IT), carbon to sulfur ratio (CSR), and impregnation time (ITE), with lower and upper bounds for process conditions being 250–600 °C IT, 0.5–4 CSR, and 15–45 min ITE. The optimum conditions were identified to be an IT of 544 °C, CSR of 0.53 and ITE of 43 min with the HgCl₂ adsorption capacity of 85 mg/g. The optimized process conditions were further ensured with repeat runs with reproducible results within acceptable variation. Langmuir and Freundlich equilibrium adsorption isotherm models fitted well with the experimental data. The maximum monolayer adsorption capacity was found to be 294 mg/g which was quite high as compared with the maximum reported in literature. Further, the SEM–EDX analysis evidence the higher amount of sulfur and uniform distribution of sulfur over the surface of activated carbon.     

Interruption of hydration state of thermoresponsive polymer,poly(N-isopropylacrylamide) in guanidinium hydrochloride

In this article, we investigate the effect of guanidinium hydrochloride (GdnHCl) on the phase transition temperature of poly (N-isopropylacrylamide) (PNIPAM) in aqueous solution with the aid of fluorescence spectroscopy, viscosity (η), and dynamic light scattering (DLS) measurements. Temperature dependent fluorescence intensity measurements have been employed successfully to determine the conformational change of PNIPAM through evaluating the Gibbs free energy changes. Additionally, direct hydrogen bonding formation between GdnHCl and PNIPAM has been confirmed by Fourier transform infrared (FTIR) spectroscopy measurements at various concentrations of GdnHCl. The intermolecular interactions were also studied in terms of amide I band analysis, which reveals the interruption of hydrated coil conformation of PNIPAM. The degree of destabilization of PNIPAM progressively increases with increasing concentration of the denaturant.