Free vibrations of rectangular orthotropic shallow shells with varying thickness

The paper proposes a numerical-analytic approach to studying the free vibrations of orthotropic shallow shells with double curvature and rectangular planform. The approach is based on the spline-approximation of unknown functions. Calculations are carried out for different types of boundary conditions. The influence of the mid-surface curvature and variable thickness on the behavior of dynamic characteristics is studied __________ Translated from Prikladnaya Mekhanika, Vol. 43, No. 6, pp. 102–115, June 2007.     

Determination of elemental concentration of seed coats of different fruits by using WDXRF spectroscopy technique

Elemental concentrations of five different seed coats of fruit seeds were determined by using wavelength-dispersive X-ray fluorescence (WDXRF) technique. Basic aim of this study is to measure mass percentages of macro, micro and trace elements in samples. Besides, analyze results have been commented in terms of correlation between the same element types in seed coats of different fruits. Some interesting results have been obtained about element quality and quantity.     

Space-angle distribution of the reflected charged particles adjusted for spin calculations

The efficiency of the proposed method of solution for the spin-considered highly anisotropic multiple scattering problem is based, following optics, upon the admission that the complete solution of the vectorial transport equation boundary problem is the superposition of the anisotropic and smooth parts, calculated separately. We use a vectorial small angle modification of the spherical harmonics method to evaluate the anisotropic part and the vectorial discrete ordinates method to obtain a smooth one. Some calculation examples for reflected radiation are given.     

Novel Fluorescent Membrane for Metronidazole Sensing Prepared by Covalent Immobilization of a Pyrenebutyric Acid Derivative

In the present paper, we report the fabrication of a new sensing membrane for fluorescence detection of metronidazole (MNZ). Briefly, a pyrenebutyric acid derivative, 2-(methacryloyloxy) ethyl-4-(1-pyrenyl) butanoate (MPB) with a double bond, was synthesized and copolymerized with 2-hydroxyethylmethacrylate (HEMA) on the activated glass surface by thermal initiation in the presence of cross-linker. The sensor responds linearly to metronidazole in the concentration range of 1.23~35.48 mg.L^?1 in aqueous solution with a detection limit of 0.36 mg.L^?1. The lifetime is enhanced by covalently immobilizing the pyrenebutyric acid derivative on glass slide, which hinders leaching of the dye from the membrane. The sensor could be regenerated after use by washing in methanol (RSD?=?2.42 %), and it shows sufficient stability, and selectivity. Interference of other pharmaceuticals on membrane performance is discussed. The developed membrane has been successfully applied for the direct determination of metronidazole in human serum sample without pretreatment.     

Some New Hermite–Hadamard and Related Inequalities for Convex Functions via (p,q)-Integral

In this investigation, for convex functions, some new (p,q)–Hermite–Hadamard-type inequalities using the notions of (p,q)π2 derivative and (p,q)π2 integral are obtained. Furthermore, for (p,q)π2-differentiable convex functions, some new (p,q) estimates for midpoint and trapezoidal-type inequalities using the notions of (p,q)π2 integral are offered. It is also shown that the newly proved results for p=1 and q→1− can be converted into some existing results. Finally, we discuss how the special means can be used to address newly discovered inequalities.     

Substrate effect on microstructure and optical performance of sputter‐deposited TiO2 thin films

This study deals with the role of the different substrates on the microstructural, optical and electronical properties of TiO₂ thin films produced by conventional direct current (DC) magnetron sputtering in a mixture of pure argon and oxygen using a Ti metal target with the aid of X–ray diffractometer (XRD), ultra violet spectrometer (UV–vis) and atomic force microscopy (AFM) measurements. Transparent TiO₂ thin films are deposited on Soda lime glass, MgO(100), quartz and sitall substrates. Phase purity, surface morphology, optical and photocatalytic properties of the films are compared with each other. It is found that the amplitude of interference oscillation of the films is in a range of 77‐89%. The transmittance of the film deposited on Soda lime glass is the smallest while the film produced on MgO(100) substrate obtains the maximum transmittance value. The refractive index and optical band gap of the TiO₂ thin films are also inferred from the transmittance spectra. The results show that the film deposited on Soda lime glass has the better optical property while the film produced on MgO(100) substrate exhibits much better photoactivity than the other films because of the large optical energy band gap. As for the XRD results, the film prepared on MgO(100) substrate contains the anatase phase only; on the other hand, the other films contain both anatase and rutile phases. Furthermore, AFM images show that the regular structures are observed on the surface of all the films studied. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)