Technical and economic assessment of hybrid photovoltaic/wind system with battery storage in Corsica island

The sizing and techno-economical optimization of a stand-alone hybrid photovoltaic/wind system (HPWS) with battery storage is presented in this paper. The main objective of the present study is to find the optimum size of system, able to fulfill the energy requirements of a given load distribution, for three sites located at Corsica island and to analyze the impact of different parameters on the system size. The methodology used provides a useful and simple approach for sizing and analyzing an HPWS. In the proposed stand-alone system, a new concept such as the supply of wind power via a uninterruptible power supply (UPS) is introduced and therefore the energy produced by the wind generator can be sent directly to the load.     

Prediction study of the structural, elastic and electronic properties of ANSr3 (A = As, Sb and Bi)

Based on first-principles total energy calculations, we predict the elastic and electronic properties of the anti-perovskites AsNSr₃, SbNSr₃ and BiNSr₃ compounds. The calculated lattice constants are in good agreement with the available results. The independent elastic constants (C₁₁, C₁₂ and C₄₄) and their pressure dependence are calculated using the static finite strain technique. The isotropic elastic moduli, namely, bulk modulus (B), shear modulus (G), Young’s modulus (E), Poisson’s ratio (σ) and Lame’s constants (λ and μ) are calculated in framework of the Voigt–Reuss–Hill approximation for ideal polycrystalline ANSr₃ aggregates. By analysing the ratio between the bulk and shear moduli, we conclude that ANSr₃ compounds are brittle in nature. We estimated the Debye temperature of ANSr₃ from the average sound velocity. The band structures show that all studied materials are semiconductors. The analysis of the site and momentum projected densities, charge transfer and charge densities show that bonding is of covalent–ionic nature. This is the first quantitative theoretical prediction of the elastic and electronic properties of AsNSr₃, SbNSr₃ and BiNSr₃ compounds that requires experimental confirmation.     

Furfuryl alcohol functionalized graphene nanosheets for synthesis of high carbon yield novolak composites

Graphene oxide and furfuryl alcohol modified graphene nanosheets (G‐FA) were used to prepare graphene/novolak composites. Effect of graphene compatibilization on the properties of the composites especially carbon yield value is evaluated. Both types of graphene nanosheets were dispersed uniquely in the novolak matrix as proved by X‐ray diffraction analysis. However, modification of graphene sheets by furfuryl alcohol results in more improved dispersions. Thermogravimetric analysis confirms the elevated thermal stability of the nanocomposites in comparison with the neat novolak. In addition, G‐FA containing composites have higher carbon yield values. A shift in the wave number of characteristic bonds of graphene after oxidation and modification with furfuryl alcohol, O? H, C?O, and C? O bonds, are seen in the Fourier transform infrared spectroscopy spectra. Raman results and scanning electron microscopy images show that graphene nanosheets reduced in size and wrinkled by oxidation and functionalization. Transmission electron microscopy image of the composite with 0.2 wt % of G‐FA reveals the presence of nanosheets with curvature. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40273.     

Optimization of the core configuration design using a hybrid artificial intelligence algorithm for research reactors

To successfully carry out material irradiation experiments and radioisotope productions, a high thermal neutron flux at irradiation box over a desired life time of a core configuration is needed. On the other hand, reactor safety and operational constraints must be preserved during core configuration selection. Two main objectives and two safety and operational constraints are suggested to optimize reactor core configuration design. Suggested parameters and conditions are considered as two separate fitness functions composed of two main objectives and two penalty functions. This is a constrained and combinatorial type of a multi-objective optimization problem. In this paper, a fast and effective hybrid artificial intelligence algorithm is introduced and developed to reach a Pareto optimal set. The hybrid algorithm is composed of a fast and elitist multi-objective genetic algorithm (GA) and a fast fitness function evaluating system based on the cascade feed forward artificial neural networks (ANNs). A specific GA representation of core configuration and also special GA operators are introduced and used to overcome the combinatorial constraints of this optimization problem. A software package (Core Pattern Calculator 1) is developed to prepare and reform required data for ANNs training and also to revise the optimization results. Some practical test parameters and conditions are suggested to adjust main parameters of the hybrid algorithm. Results show that introduced ANNs can be trained and estimate selected core parameters of a research reactor very quickly. It improves effectively optimization process. Final optimization results show that a uniform and dense diversity of Pareto fronts are gained over a wide range of fitness function values. To take a more careful selection of Pareto optimal solutions, a revision system is introduced and used. The revision of gained Pareto optimal set is performed by using developed software package. Also some secondary operational and safety terms are suggested to help for final trade-off. Results show that the selected benchmark case study is dominated by gained Pareto fronts according to the main objectives while safety and operational constraints are preserved.     

Mixed near-field and far-field source localization revised: propagation loss included

Multidimensional Systems and Signal Processing - This paper is concerned with source localization when path loss is taken into account. We modify multiple signal classification method to localize...     

Circular array design based on Bayesian Cramer–Rao bound

Multidimensional Systems and Signal Processing - In this paper, we consider circular array design in the presence of a far-field or a near-field signal source. The location of the source is...     

Expandable styrene/methyl methacrylate copolymer: Synthesis and determination of VOCs by combined thermogravimetry/differential thermal analysis‐gas chromatography/mass spectrometry

Parts cast of metals using expandable polystyrene foams may have an unacceptable amount of surface defects, such as lustrous carbon. The use of foams made of styrenic/acrylic copolymers can improve the quality of foam molds and metal parts made using such molds. Lost foam copolymer was synthesized by suspension copolymerization of styrene and methyl methacrylate. The polymerization was carried out in the presence of blowing agents. The decomposition products of lost foam beads were studied by a method composed of the thermogravimetry/differential thermal analysis (TG/DTA) and gas chromatography/mass spectrometry (GC/MS). With these systems, the TG/DTA data can be combined with a GC separation and MS identification methods. This combined method improves the analysis of the decomposition products of lost foam beads and enables the precise identification of the amount and the nature of volatile organic compounds (VOCs) trapped during suspension polymerization. The results obtained from the combined method were verified for the nature and amount of VOCs with the results of time‐conversion studies for copolymerization of monomers in the presence of different concentrations of blowing agent. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis and characterization of poly(styrene‐co‐butyl acrylate)/clay nanocomposite latexes in miniemulsion by AGET ATRP

Polymer/clay nanocomposite latexes in the form of positively charged nanoparticles were synthesized by a newly developed initiating system, activators generated by electron transfer (AGET), which has been employed in atom transfer radical polymerization (ATRP). These clay‐dispersed latexes were synthesized using AGET ATRP of styrene and butyl acrylate in a miniemulsion system in which, ascorbic acid as a reducing agent was added drop wise to reduce termination reactions. Particle size and particle size distribution of resulted nanocomposite latexes were characterized by dynamic light scattering (DLS). These latexes were in the range of 138 to 171 nm in size. Gel permeation chromatography (GPC) was used to characterize the molecular weight and molecular weight distribution of the resultant copolymer nanocomposites. GPC traces showed that polymers of narrow molecular weight distribution and low Polydispersity Index (PDI) have been synthesized; this clearly shows ATRP reaction is conducted successfully. By increasing nanoclay content, molecular weight of the nanocomposites decreases. The presence of the nanofiller increases the thermal stability of the nanocomposites as investigated by thermogravimetric Analysis (TGA). Glass transition temperature of nanocomposites increases compared with the neat copolymer which was studied by differential scanning calorimetry (DSC). scanning electron microscope (SEM) showed sphere morphology of polymer particles synthesized by miniemulsion polymerization. X‐ray diffraction (XRD) and transmission electron microscopy (TEM) results showed that mixed intercalated and exfoliated morphology is obtained. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

Nanoclay‐encapsulated polystyrene microspheres by reverse atom transfer radical polymerization

Nanoclay‐encapsulated polystyrene microspheres were synthesized using reverse atom transfer radical polymerization in miniemulsion. Conversion and molecular weight were evaluated using gravimetry and gel permeation chromatography, respectively. Accordingly, conversion and molecular weight decrease by adding clay content. However, polydispersity index of the nanocomposites with higher clay content is higher. At high temperatures, thermal stability of the nanocomposites is relatively higher than the neat polystyrene, according to the thermogravimetric analysis results. Differential scanning calorimetry results show that glass transition temperature decreases by increasing clay content. Transmission electron microscopy result is in coincidence with X‐ray diffraction data and shows that clay layers are exfoliated in the matrix of PSNM 1. Scanning electron microscopy images display a homogeneous distribution of spherical particles with sizes in the range of ∼200 nm and also confirm dynamic light scattering (DLS) results. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers     

Evaluation of the confinement effect of nanoclay on the kinetics of styrene atom transfer radical polymerization

The grafting through method was employed to study the effect of nanoclay confinement on the atom transfer radical polymerization (ATRP) of styrene. An ammonium salt containing a double bond on its structure was used as a clay modifier. Employing ATRP to polymerize styrene in the presence of modified montmorillonite resulted in a finely well‐defined polystyrene nanocomposite. The gas chromatography (GC) results showed the linear increase of ln(M₀/M) versus time, which indicated the controlled behavior of the polymerization. Another confirmation of the living nature of the polymerization was the linear increase of molecular weight against monomer conversion concluded from the gel permeation chromatography (GPC) data. Nanoclay exerted acceleration on the polymerization of free polystyrene chains. The polydispersity indexes of polymer chains increased by the addition of nanoclay. In the case of clay‐attached polystyrene chains, number and weight‐average molecular weights were lower than that of freely dispersed polystyrene chains. The polydispersity index of the clay‐attached chains was higher in respect to the freely dispersed polystyrene chains. The living nature of polymer chains was more elucidated by Fourier transform infrared spectroscopy (FTIR). Exfoliation of the clay layers in the polymer matrix of polystyrene nanocomposite containing the lowest amount of nanoclay has proven by Transmission Electron Microscopy (TEM). © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011