A new analytical formula to compute the step length of Padé approximants in the ANM: Application to buckling structures

In this paper, we propose a new analytical formula to define the next branch in the Asymptotic Numerical Method (ANM) using the Padé approximants. The proposed formula is based on the computation of the relative error of two consecutive Padé approximants. This formula is obtained by developing the relative error with respect to the path parameter. An appropriate matrix formulation is adopted for the computation of this relative error. A comparison between the analytical formula proposed in this paper and the classical continuation Padé approximants using the step length computed numerically using dichotomy method is presented for examples of buckling structures.     

Green synthesis and characterization of silver nanoparticles using Juniperus communis leaf extract: Catalytic activity in real-outdoor conditions and electrochemical properties

The present study investigates the green synthesis of stable silver nanoparticles using Juniperus communis leaf aqueous extract at room temperature. Synthesized silver nanoparticles (AgNPs) were characterized with different techniques such as UV–vis spectroscopy, Fourier transforms infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), Scanning electron microscopy (SEM-EDAX) and electrochemical method. Photocatalytic and anti-bacterial activities of synthesized AgNPs are evaluated based on the obtained result showed an efficient inhibition growth for gram negative P. Aeruginosa, E. Coli, and gram positive bacteria S.aureus. The AgNPs exhibited an excellent photocatalytic activity toward the degradation of methylene blue both indoor and outdoor, under sunlight, an efficiency of 95% was achieved. As an easy and environmentally friendly process, AgNPs based on Juniperus communis leaf extract could be applied for the degradation of pollutants and wastewater treatment.     

A new logarithmic-quadratic proximal method for nonlinear complementarity problems

In this paper, we propose a new modified logarithmic-quadratic proximal (LQP) method for solving nonlinear complementarity problems (NCP). We suggest using a prediction-correction method to solve NCP. The predictor is obtained via solving the LQP system approximately under significantly relaxed accuracy criterion and the new iterate is computed by using a new step size α_k. Under suitable conditions, we prove that the new method is globally convergent. We report preliminary computational results to illustrate the efficiency of the proposed method. This new method can be considered as a significant refinement of the previously known methods for solving nonlinear complementarity problems.     

Resistivity and thermoelectric power of molten aluminium: experiment and theory

The electrical resistivity?ρ?of metallic liquid aluminium is measured as a function of temperature. The measurement needs an experimental design able to get the resistivity of a very reactive liquid metal. Liquid aluminium seems to be a simple metal. We first interpret the experimental results by using an ab initio calculation of the electrical resistivity ρ(E) as function of the electron energy, taking into account recent exchange and correlation contributions in the framework of the generalized gradient approximation (GGA). But surprisingly the classical theoretical interpretation leads to an apparent inconsistency. Thus we discuss the sensitivity of the calculation on the inputs and propose improvements of the theoretical approach. They allow a better physical understanding of pure liquid aluminium which is absolutely necessary before undertaking the study of liquid aluminium alloys.     

Spin treatment-based approach for electronic transport in paramagnetic liquid transition metals

A novel concept is proposed to calculate both the electrical resistivity and thermoelectric power (TEP) of liquid transition metals (Mn, Fe, Co and Ni) characterized by a paramagnetic state in the liquid phase. By contrast to a previous work (PRB64, 094202 (2001)), where the resistivity was calculated by treating separately the interactions between spin up and spin down using the Matthiessen rule, our current approach is based on two types of muffin tin potentials in the t-matrix, namely spin up and spin down. The resistivity is treated as the result of the interference of the two kinds of spin states of electrons including a cross-contribution. The calculated resistivity values agree reasonably well with the available experimental ones for all the metals considered. Moreover, the calculated TEP, as deduced from the slope of resistivity vs. energy, has been found to be positive for Mn and Fe but negative for Co and Ni. Besides that, this formalism for resistivity calculation may be generalized to a system that may exist in different atomic states. It is worth mentioning that this concept is analogous to the one used in the process of neutron scattering on a metal composed of multiple isotopes.     

Fundamental study of crystallization,orientation, and electrical conductivity of electrospun PET/carbon nanotube nanofibers

The morphology, structure, and properties of polyethylene terephthalate (PET)/Carbon Nanotubes (CNT) conductive nanoweb were studied in this article. Nanocomposite nanofibers were obtained through electrospinning of PET solutions in trifluoroacetic acid (TFA)/dichloromethane (DCM) containing different concentrations and types of CNTs. Electrical conductivity measurements on nanofiber mats showed an electrical percolation threshold around 2 wt % multi‐wall carbon nanotubes (MWCNT). The morphological analysis results showed smoother nanofibers with less bead structures development when using a rotating drum collector especially at high concentrations of CNTs. From crystallographic measurements, a higher degree of crystallinity was observed with increasing CNT concentrations above electrical percolation. Spectroscopy results showed that both PET and CNT orientation increased with the level of alignment of the nanofibers when the nanotube concentration was below the electrical percolation threshold; while the orientation factor was reduced for aligned nanofibers with higher content in CNT. Considerable enhancement in mechanical properties, especially tensile modulus, was found in aligned nanofibers; at least six times higher than the modulus of random nanofibers at concentrations below percolation. The effect of alignment on the mechanical properties was less important at higher concentrations of CNTs, above the percolation threshold. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 2052–2064, 2010     

Electron transfer in quantum-dot-sensitized ZnO nanowires: ultrafast time-resolved absorption and terahertz study

Photoinduced electron injection dynamics from CdSe quantum dots to ZnO nanowires is studied by transient absorption and time-resolved terahertz spectroscopy measurements. Ultrafast electron transfer from the CdSe quantum dots to ZnO is proven to be efficient already on a picoseconds time scale (τ = 3-12 ps). The measured kinetics was found to have a two-component character, whose origin is discussed in detail. The obtained results suggest that electrons are injected into ZnO via an intermediate charge transfer state.     

Antibacterial and antioxidant potency of floral honeys from different botanical and geographical origins

In order to assess their physicochemical and antioxidant properties as well as their antimicrobial potency, four varieties of honey from different botanical and geographical origins were used. The agar incorporation method was used to determine the antimicrobial potency of honeys. The total phenol content was determined by a modified Folin-Ciocalteu method and the free radical scavenging activity by the Fe³⁺ reducing power (FRAP) assay. Manuka honey was the most effective against Staphylococcus aureus Oxa R and S. aureus Oxa S with a Minimum Inhibitory Concentration (MIC) of 6% and 7%, respectively, whereas wild carrot honey was the most effective against Pseudomonas aeruginosa, with a MIC of 12%. Lavender honey was the least effective against all tested strains, even though was found to have the lowest pH and water content. Manuka honey had the highest content of polyphenols, with 899.09 ± 11.75 mg gallic acid/kg, whereas lavender honey had the lowest, with 111.42 ± 3.54 mg gallic acid/kg. A very significant correlation (r value was 0.9079 at P < 0.05) was observed between the total polyphenolic content and the Fe²⁺ content formed in the presence of the honey antioxidants. The differences between honey samples in terms of antibacterial and antioxidant activity could be attributed to the natural variations in floral sources of nectar and the different locations.     

Equivariant functions and integrals of elliptic functions

In this paper, we introduce the theory of equivariant functions by studying their analytic, geometric and algebraic properties. We also determine the necessary and sufficient conditions under which an equivariant form arises from modular forms. This study was motivated by observing examples of functions for which the Schwarzian derivative is a modular form on a discrete group. We also investigate the Fourier expansions of normalized equivariant functions, and a strong emphasis is made on the connections to elliptic functions and their integrals.     

Projection iterative method for solving general variational inequalities

In this paper, we suggest and analyze a new projection iterative method for solving general variational inequalities by using a new step size. We also prove the global convergence of the proposed method under some suitable conditions. Some preliminary numerical experiments are included to illustrate the advantage and efficiency of the proposed method.