Hybrid intelligent framework for one-day ahead wind speed forecasting

Neural Computing and Applications - Nowadays wind power is considered as one of the fastest growing alternative energies, that is expected to continue to grow rapidly in the upcoming...     

Synthesis and evaluation of the thermal properties of biosourced poly(ether)ureas and copoly(ether)ureas from 1,4:3,6‐dianhydrohexitols

A new series of poly(ether)ureas were prepared by solution polyaddition of three diamines based on 1,4:3,6‐dianhydrohexitols with three types of diisocyanate. The corresponding poly(ether)ureas were obtained with high yields. They were characterized by various analytical techniques (NMR, TGA and differential thermal analysis, DSC). NMR spectroscopy allowed us to confirm structure type and to optimize reaction conditions and DSC proved the high thermal properties of the products obtained (T_g and T_m in the range 126 ? 158 °C and 235 ? 330 °C respectively). Then, copoly(ether)ureas partially based on commercial diamines were synthesized in order to reduce polymer cost and tune their thermal behaviour. The reactivity of both diamines was evaluated by their incorporation in the polymer by means of NMR spectra. Then their thermal properties were compared with fully commercial diamine based polyureas by DSC studies. © 2014 Society of Chemical Industry     

Modeling of Dispersive Materials Using Dispersion Models for FDTD Application

A nonlinear optimization algorithm based on the Nelder Mead method is used to characterize the frequency dependent permittivity of 15 materials based on Lorentz, modified Lorentz, Drude and Lorentz-Drude models. The optimized model parameters are used to calculate the complex relative permittivity of each material and compare it with experimental data. In each case, a very good match is found between the optimized and experimental data over a long wavelength range. Comparative study of the models used for each material is performed based on accuracy, wavelength range of applicability and computational efficiency. The parameters presented can be used for computer simulation of electromagnetic wave phenomena involving these materials.     

Viability of Lactobacillus acidophilus in rice bran‐enriched stirred yoghurt and the physicochemical and sensory characteristics of product during refrigerated storage

This study was aimed at investigating the fortification of probiotic yoghurt with rice bran to increase nutritional properties of the product. The different levels of rice bran (0.3%, 0.6%, 0.9% and 1.2%) were incorporated into milk. The yoghurt samples were produced after pasteurisation, addition of starter culture and 1% Lactobacillus acidophilus suspension (6 × 10⁸ CFU mL^?1) and incubation. During sample storage in refrigerator, the viability of L. acidophilus, viscosity and physicochemical and sensory properties of product were investigated. Rice bran significantly increased the viability of L. acidophilus (P < 0.05). In addition, all probiotic yoghurts incorporating rice bran indicated higher viscosity and acidity and lower pH and syneresis compared to plain yoghurts. Furthermore, increments in rice bran incorporation levels resulted in a reduction in consumers' sample preferences. In general, the addition of rice bran at a suitable level could increase L. acidophilus viability and improve quality attributes of yoghurt.     

Photocatalytic degradation of methyl orange dye by NiFe<Subscript>2</Subscript>O<Subscript>4</Subscript> nanoparticles under visible irradiation: effect of varying the synthesis temperature

Nanoparticles of nickel ferrites (NiFe₂O₄) were synthesized at different temperature of synthesis (25, 50 and 80 °C) through the chemical co-precipitation method. The synthesized powders were characterized using X-ray diffraction for crystallite size and lattice parameter calculation. It reveals the presence of cubic spinel structure of ferrites with crystallite size between 29 and 41 nm. Transmission electron microscopy and scanning electron microscopy showed uniform distribution of ferrite particles with some agglomeration. The Fourier-transform infrared spectroscopy showed absorption bonds, which were assigned to the vibration of tetrahedral and octahedral complexes. Raman spectroscopy is used to verify that we have synthesized ferrite spinels and determines their phonon modes. The thermal decomposition of the NiFe₂O₄ was investigated by TGA/DTA. The optical study UV–visible is used to calculate the band gap energy. Magnetic measurements of the samples were carried out by means of vibrating sample magnetometer and these studies reveal that the formed nickel ferrite exhibits ferromagnetic behavior. Photoluminescence showed three bands of luminescence located at 420, 440 and 535 nm. The photocatalytic properties of nickel ferrite (NiFe₂O₄) nanoparticles were evaluated by studying the photodecomposition of methyl orange as organic pollutant models and showed a good photocatalytic activity.     

Thermal analysis of above-grade wall assembly with low emissivity materials and furred airspace

A 3D numerical model was developed to investigate the effect of foil emissivity on the effective thermal resistance of an above-grade wall assembly with foil bonded to wood fibreboard in a furred assembly having airspace next to the foil. This model solved simultaneously the energy equation in the various material layers, the surface-to-surface radiation equation in the furred airspace assembly, Navier–Stokes equation for the airspace, and Darcy and the Brinkman equations for the porous material layers. In this work, the furring was installed horizontally. In the first phase, the present model was benchmarked against the experimental data generated by a commercial laboratory for an above-grade wall assembly. The wall consists of a conventional wood frame structure sheathed with fibreboard and covered on the interior side with a low emissivity material bonded to wood fibreboard that is adjacent to a furred airspace assembly. The results showed that the predicted R-value was in good agreement with the measured one. After gaining confidence in the present model, it was used to predict the effective thermal resistance of the same above-mentioned wall but having Oriented Strand Board (OSB) sheathing in lieu of wood fibreboard sheathing. In the second phase, the model was used to quantify the contribution on the wall R-value by having a low foil emissivity. The results showed that a low foil emissivity of 0.04 can increase the R-value of this wall to as much as ∼9%. This is on-going research. The present model is being used to investigate the transient thermal response of foundation wall systems with furring installed horizontally and vertically, and subjected to different Canadian climate conditions.     

A constraint consensus memetic algorithm for solving constrained optimization problems

Constraint handling is an important aspect of evolutionary constrained optimization. Currently, the mechanism used for constraint handling with evolutionary algorithms mainly assists the selection process, but not the actual search process. In this article, first a genetic algorithm is combined with a class of search methods, known as constraint consensus methods, that assist infeasible individuals to move towards the feasible region. This approach is also integrated with a memetic algorithm. The proposed algorithm is tested and analysed by solving two sets of standard benchmark problems, and the results are compared with other state-of-the-art algorithms. The comparisons show that the proposed algorithm outperforms other similar algorithms. The algorithm has also been applied to solve a practical economic load dispatch problem, where it also shows superior performance over other algorithms.     

光盘进化带来的视听革命

当我们沉浸在在1080p高清影音之中的时候，你可曾还记得早期的CD音乐．VCD电影？从VCD、DVD 到BD，每一次变革都给人们的视听带来了质的变化。在视听水平不断升级的背后．光盘的进化功不可没。下面．请跟随我们“穿越”到二十多年前．一起回顾光盘的不断进化给人们带来的视听革命吧。