Electrochemical characterization of the redox couple of Fe(III)/Fe(II) mediated by grafted polymer electrode

A new grafted polymer electrode (GPE) (polystyrene as polymer) was grafted with acrylonitrile as a monomer using gamma irradiation to produce a new grafted polymer. The redox process of K₃Fe(CN)₆ during cyclic voltammetry was studied by the new GPE. The ratio of Ipc/Ipa >1 of GPE to GCE Ipc/Ipa = 1.7, indicating that this electrode is a reversible electrode and can be used in conductivity studies by voltammetric analysis. The physical properties of the new electrode GP have good hardness, insolubility, and stability at different high temperatures and at different pH. Also, the sensitivity under conditions of cyclic voltammetry is significantly dependent on pH, electrolyte, and scan rate. At different scan rates, two oxidation peaks and two reduction peaks of Fe(III) were observed in a reversible process: Fe(III) Fe(II), and Fe(II) Fe(0). Interestingly, the redox reaction of Fe(III) solution using GPE remained constant even after 15 cycles. It is therefore evident that the GPE possesses some degree of stability. The potential use of the grafted polymer as a useful electrode material is therefore clearly evident.     

Electrochemical characterization of the redox couple of Fe(III)/Fe(II) mediated by grafted polymer reference electrode (GPRE)

A grafted polymer reference electrode (GPRE) (polystyrene grafted with acrylonitrile as a monomer using gamma irradiation) was fabricated as a reference electrode using cyclic voltammetry (CV). The redox process of K₃Fe(CN)₆ during CV was studied. It was found that the redox current peaks of Fe(II)/Fe(III) in 0.1 M of KCl as supporting electrolyte is given the same oxidation–reduction current as in the Ag/AgCl reference electrode, indicating a good result of GPRE and, hence, it can be used for voltammetric analysis technique. The physical properties of GPRE include good hardness, insoluble in non-aqueous electrolytes (except dimethyl formamide and chloroform), and good stability at different solvents. In addition, the sensitivity under conditions of CV is significantly dependent on the scan rate (SR) and variation in concentration. At different SRs, redox peaks of K₃Fe(CN)₆ were observed in a reversible process: Fe(II)/Fe(III). Interestingly, the redox reaction of Fe(II)/Fe(III) solution using GCE versus GPRE remains constant even after 15 cyclings. It is therefore evident that the GPRE possesses some degree of stability. Also, the new reference electrode GPRE has improved the properties of electroanalysis of CV on the working electrode GCE in reliability with the relative standard deviation.     

Single-particle quadrupole electromagnetic transitions in p-shell and sd-shell nuclei

Electron scattering Coulomb form factors for the single-particle quadrupole transitions in p-shell and sd-shell nuclei have been studied. Core polarization effects are included through a microscopic theory that includes excitations from the core orbits up to higher orbits with 2ω excitations. The modified surface delta interaction is adopted as a residual interaction. The results are discussed for the ( 1p _1/2 ^-1↦1p _3/2 ^-1) proton transition in ¹⁵N, ( 1d _5/2↦2s _1/2) neutron transition in ¹⁷O and ( 1d _3/2 ^-1↦2s _1/2 ^-1) proton transition in ³⁹K. The inclusion of core polarization effects modifies the form factors markedly and describes the experimental data very well in both the absolute strength and the momentum transfer dependence. Received: 18 April 2002 / Accepted: 1 July 2002 / Published online: 6 March 2003 RID="a" ID="a"e-mail: baguniv@uruklink.net Communicated by A. Molinari     

Microwave-assisted synthesis of novel 2,3-dihydro-4-pyridinones

Novel 2,3-dihydro-4-pyridinones were synthesized via the reaction of curcumin and primary amines or amine acetates under microwave irradiation. Montmorillonite K-10 was used as a catalyst. Reaction times did not exceed 120 s. The structures of the compounds were established by elemental analysis and from their mass, 1H- and 13C-NMR spectra.     

Critical Point of the 152Sm, 154Gd,and 156Dy Isotones

Physics of Atomic Nuclei - The even—even rare-earth nuclei in U(5)—SU(3) region at neutron number (N) = 90, have been systematically studied using the Bohr—Mottelson Model (BM),...     

Propagation of a Dugdale crack at the edge of a half plane

This work deals with the propagation of a Dugdale crack at the edge of a half plane. The corresponding singular integral equation is solved semi-analytically. The expressions of the stress intensity factor and of the crack gap are deduced. A propagation criterion deduced from the revisited Griffith theory (Ferdjani and Marigo in Eur J Mech A Solids 53:1–9, 2015) is applied. The length of the process zone is calculated and compared with the literature results. The presented results show the evolution of the applied load with the crack length for different values of the ratio of the critical length of the Dugdale model to the initial crack length. The shape of the crack gap is also presented. Finally, a comparison between the Griffith and Dugdale models is performed.     

Perturbative role in the inelastic electron scattering from <Superscript>29</Superscript>Si

Inelastic electron scattering form factors away from the closed sd -shell are investigated. This investigation covers the low-lying states in ²⁹Si , which is considered according to the many-particle configuration mixing shell model as the ¹⁶O core, plus thirteen nucleons distributed over the entire sd -shell orbits. The investigation concentrates on the perturbative role of the core, which is called core polarization effects, on the inelastic electron scattering form factors. Core polarization effects are taken into consideration through the excitation of nucleons from 1s and 1p core orbits, and also from the 2s -1d valence orbits into higher shells, with 2ℏω excitations. Core polarization matrix elements are calculated with the M3Y effective interaction. For the sd -shell model space, a new Hamiltonian, based on a renormalized G -matrix, USDB, is used. All calculations are performed without adjusting any parameters.     

Core polarization effects on C4 form factors of sd-shell nuclei

Coulomb form factors of C4 transitions in even-even N = Z sd-shell nuclei ( ²⁰Ne, ²⁴Mg, ²⁸Si and ³²S) are discussed taking into account higher-energy configurations outside the sd-shell model space which are called core polarization effects. Higher configurations are taken into account through a microscopic theory, which allows particle-hole excitations from the 1s and 1p shells core orbits and also from the 2s1d-shell orbits to the higher allowed orbits with excitations up to 4 ω. The effect of core polarization is found essential in both the transition strengths and momentum transfer dependence of form factors, and gives a remarkably good agreement with the measured data with no adjustable parameters. The calculations are based on the Wildenthal interaction for the sd-shell model space and on the modified surface delta interaction (MSDI) for the core polarization effects. Received: 24 January 2002 / Accepted: 29 July 2002 / Published online: 6 March 2003 RID="a" ID="a"e-mail: baguniv@uruklink.net Communicated by P. Schuck     

Electric quadrupole and hexadecupole nuclear excitations from the perspectives of electron scattering and modern shell-model theory

Shell-model wave functions obtained from a complete, unified treatment of the structure of the positive parity states in nuclei between ¹⁶O and ⁴⁰Ca are used to calculate the features of inelastic electron scattering to 2+ and 4+ states in this region. These predictions of E2 and E4 form factors, and the corresponding elastic scattering predictions, are compared with the collected experimental data which are available on this topic. The dependence of the calculated results upon alternate models for single-nucleon wave functions and core-polarization transition densities is investigated, as is the consistency between the (e,e′) measurements and the analogous B(E2) measurements.     

Negative-parity states of75As and the interacting boson-fermion model

The result of an IBFM multilevel calculation with the 2p_3/2, 1f_5/2 and 2p_1/2 single particle orbits is reported for the negative parity states of the odd mass nucleus⁷⁵As. Comparisons are made with experimental data for energy spectra, transition probabilities, mixing ratios, electric quadrupole and magnetic dipole moments. Also, an IBM-1 calculation is presented for the low-lying states in the even-even⁷⁴Ge core nucleus.