Poly(glycidylmethacrylate-co-vinyl ferrocene)-grafted iron oxide nanoparticles as an electron transfer mediator for amperometric phenol detection

An amperometric phenol biosensor was constructed by using poly(glycidylmethacrylate-co-vinyl ferrocene) grafted iron oxide nanoparticles for detection of different phenolic compounds (catechol, aminophenol, phenol, p-cresol, pyrogallol). The poly(glycidylmethacrylate-co-vinyl ferrocene) and nanoparticles were characterized by Fourier transform infrared (FT-IR), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The copolymer grafted iron oxide nanoparticles and Horseradish peroxidase (HRP) were covalently attached on gold (Au) electrode surface. The effect of pH, temperature and characteristic features such as; reusability and storage stability were studied. The electrode showed good response time within ～3 s. The electrocatalytic response showed a linear dependence on the phenolic compounds concentration ranging from 0.5 to 17.0 mM.     

CTAB-Mn3O4 nanocomposites: Synthesis,NMR and low temperature EPR studies

We are reporting on the synthesis of Mn₃O₄ nanoparticles and CTAB-Mn₃O₄ nanocomposites via a sonochemical route using MnCl₂, ethanol, NaOH and CTAB. The crystalline phase was identified as Mn₃O₄. The crystallite size of the CTAB-Mn₃O₄ nanocomposite was identified as 13 ± 5 nm from X-ray line profile fitting and the particle size from TEM was 107.5 ± 1.4 nm. The interaction between CTAB and the Mn₃O₄ nanoparticles was investigated by FTIR and ¹H NMR spectroscopies. Two different magnetic phase transitions were observed for both samples below the Curie temperature (43 °C) by using a low temperature Electron Paramagnetic Resonance (EPR) technique. Also we determined the effect of the capping with CTAB on the reduction in absorbed power.     

Scintillations of Laguerre Gaussian beams

By using the Rytov method, we formulate and numerically evaluate the scintillations of Laguerre Gaussian beams in weak atmospheric turbulence. Our results indicate that at on-axis positions, Laguerre Gaussian beams with zero angular mode number will have less scintillations than fundamental Gaussian beams, where the amount of scintillations will further decrease with rising radial mode number. When off-axis positions are considered, this situation reverses however, and the scintillations of Laguerre Gaussian beams become generally higher than the fundamental Gaussian beam. Plotted against the source size, the on-axis scintillations of Laguerre Gaussian beams fall below the fundamental Gaussian beam, following the same trend as the fundamental Gaussian beam all throughout the source size range examined.     

Radius of curvature variations for annular, dark hollow and flat topped beams in turbulence

For propagation in turbulent atmosphere, the radius of curvature variations for annular, dark hollow and flat topped beams are examined under a single formulation. Our results show that for collimated beams, when examined against propagation length, the dark hollow, flat topped and annular Gaussian beams behave nearly the same as the Gaussian beam, but have larger radius of curvature values. Increased partial coherence and turbulence levels tend to lower the radius of curvature. Bigger source sizes on the other hand give rise to larger radius of curvature. Dark hollow and flat topped beams have reduced radius of curvature at longer wavelengths, whereas the annular Gaussian beam seems to be unaffected by wavelength changes; the radius of curvature of the Gaussian beam meanwhile rises with increasing wavelength.     

Degree of polarization for partially coherent general beams in turbulent atmosphere

The degree of polarization is found for optical excitations of cosh-Gaussian, cos-Gaussian and annular-Gaussian beams in a turbulent atmosphere. The related formulation is based on the beam coherence polarization matrix. The self and mutual coherence functions appearing in the beam coherence polarization matrix are evaluated, when the above mentioned excitations exhibit partial source coherence for self and cross fields. Plots showing the variation of the degree of polarization are provided versus the propagation length when the source size, displacement parameter, structure constant and the degree of source coherence for self and cross fields change. PACS 42.25.Dd; 42.25.Ja; 42.25.Kb     

Synthesis and application of magnetically recyclable nanocatalyst Fe3O4@Nico@Cu in the reduction of azo dyes

A novel method for synthesizing magnetically recyclable nanocatalyst Fe3O4@Nico@Cu (Nico =nicotinic acid) was introduced. The structural, morphological, and magnetic properties of the nano-catalyst were characterized by Fourier transform infrared spectroscopy, X-ray powder diffraction, scanning electron microscopy, and vibrating sample magnetometry. Finally, Fe3O4@Nico@Cu was examined toward the hydrogenation of azo dyes methyl orange, methylene blue, eosin Y, and rho-damine B. The nanocatalyst showed excellent reusability properties that remained unchanged after several catalytic cycles. Therefore, the current findings show the potential of the prepared Fe3O4@Nico@Cu nanocatalyst as a candidate for application in the purification of organic aqueous pollutants for wastewater treatment.     

Field correlations of flat-topped Gaussian and annular beams in turbulence

Starting from the second order moment formulation for multi-beam incidence, field correlations at the receiver plane of flat-topped Gaussian and annular beams are found in turbulence. Reflecting the information on both the randomness due to turbulence and the field profile of the incident field, field correlations of the flat-topped Gaussian beams are found to become larger at larger source size, smaller flatness parameters and smaller turbulence strengths. For the annular beam structures, field correlations are larger for thicker beams. Field correlations of larger primary beam sized annular incidences are smaller at smaller diagonal distances and larger at larger diagonal distances. As expected, annular beam field correlations are found to be larger at smaller structure constants and at smaller wavelengths. However, at large link lengths, field correlations could be larger than at smaller link lengths due to fact that for annular beams, the field at the centre of the receiver attains very small value at smaller link lengths, however, on propagation in turbulence, receiver field distribution changes to a Gaussian profile.     

On identity for eigenvalues of second order differential operator equation

In this study we investigate the spectrum and regularized trace of the second order differential operator equation with periodic boundary conditions.     

X-ray powder diffraction,FTIR, and raman study of strontium boroarsenate,SrBAsO<Subscript>5</Subscript>

In this study, SrBAsO₅ was synthesized by a solid state reaction using SrCO₃, As₂O₅, and H₃BO₃ as reported before. The x-ray powder diffraction, FTIR, and Raman data were in agreement with the reported crystal structure. It crystallizes in a hexagonal system in P3₁21, and the refined unit cell parameters are a = 7.056(3) Å, c = 6.898(1) Å, and Z = 3. It is isostructural with SrBPO₅. FTIR and Raman investigation of this compound were done for the first time in this study.