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In this work, PANI/MnC[o.sub.2][O.sub.4] nanocomposite was prepared via in-situ chemical polymerization method. Materials synthesized were characterized by FTIR spectroscopy, X-ray diffraction, and scanning electron spectroscopy. In addition, surface characterization of samples such as specific surface area, pore volume, and pore size distribution was studied. Supercapacitor capability of materials was investigated in 1 mol [L.sup.-1] [Na.sub.2]S[O.sub.4] solution using cyclic voltammetry in different potential scan rates and electrochemical impedance spectroscopy (EIS). The specific capacitance of materials was calculated, and it was observed that the specific capacitance of PANI/MnC[o.sub.2][O.sub.4] nanocomposite was 185 F [g.sup.-1], much larger than PANI. Moreover, the prepared nanocomposite exhibited better rate capability in scan rate of 100 mV [s.sup.-1] with respect to PANI. The EIS experiments revealed that the nanocomposite has lower charge transfer resistance compared with pure PANI. Subsequently, it was shown that the nanocomposite cycling performance was superior to the PANI cycling performance. Key words: polyaniline, MnC[o.sub.2][O.sub.4] nanoparticles, nanocomposite, supercapacitor, EIS. Dans le cadre des présents travaux, nous avons synthétisé le nanocomposite PANI/MnC[o.sub.2][O.sub.4] par une méthode de polymérisation chimique in situ. Nous avons caractérisé les matériaux ainsi préparés par spectroscopie FTIR, diffraction des rayons X et spectroscopie électronique à balayage. En outre, nous avons caractérisé leur surface en soumettant les échantillons à des analyses de la surface spécifique, la porosité et la répartition de la taille des pores. Par ailleurs, nous avons étudié le potentiel supercondensateur des matériaux dans une solution de [Na.sub.2]S[O.sub.4] à 1 mol [L.sup.-1] parvoltampérométrie cyclique à différentes vitesses de balayage de potentiel de même que par spectroscopie d'impédance électrochimique (SIE). Nos calculs de la capacitance spécifique de ces matériaux indiquent que celle du nanocomposite PANI/MnC[o.sub.2][O.sub.4] était de 185 F [g.sup.-1], dépassant largement celle du PANI. De plus, le nanocomposite que nous avons préparé présentait une meilleure capacité de vitesse que celle du PANI à une vitesse de balayage de 100 mV [s.sup.-1]. Les expériences de SIE ont révélé que le nanocomposite présentait une résistance au transfert de charge moins élevée que celle du PANI pur. Par la suite, nous avons montré que la performance de cycle du nanocomposite était supérieure à la capacité de cyclage du PANI. [Traduit par la Rédaction] Mots-clés : polyaniline, nanoparticules de MnC[o.sub.2][O.sub.4], nanocomposite, supercondensateur, SIE., Introduction Supercapacitors, or electrochemical capacitors, due to their excellent performance, including ultra-high power density, long cycling stability, wide operation temperature range, and improved safety, have attracted attention as 'green' and [...]

This article focuses on the steady motion of yawed planing hulls with emphasis on the effects of adding steps to the bottom of these vessels on the hydrodynamic forces and moments acting on the boat. To analyze the problem, the Ansys-CFX software is used and three different planing hulls are investigated in steady yawed condition. The main targeted results include hydrodynamic forces and moments acting on the boat at different yaw angles and beam Froude numbers which provide important insights regarding the effects of loading and adding step on these forces and moments. The numerically predicted sway forces are compared against experimental data, suggesting that the current numerical model predicts sway and surge forces with reasonable accuracy. Moreover, it is observed that surge force coefficient of the investigated prismatic planing hull with light loading condition does not change significantly when the hull is relocated in a yaw angle, while it is remarkably affected when the boat is heavy. Furthermore, it is observed that this prismatic planing hull has smaller rolling moment in a steady yawed motion, when it moves at larger beam Froude number. Meanwhile, the computed yawing moments of this hull indicate that an increase in speed does not change this moment notably, while an increase in its weight yields larger yawing moment. Comparison of the results of stepped and non-stepped planing hulls indicates that surge force coefficient of the stepped hull is larger, while its sway force and rolling moment are smaller. This is mainly caused by the shape of the interrupted wetted surface and larger number of maximum pressure area in the stepped planing hull. Finally, it is concluded that there is no significant difference between the yawing moment of the investigated stepped and non-stepped planing hulls. [ABSTRACT FROM AUTHOR]

In this work, PANI/MnCo2O4 nanocomposite was prepared via in-situ chemical polymerization method. Materials synthesized were characterized by FTIR spectroscopy, X-ray diffraction, and scanning electron spectroscopy. In addition, surface characterization of samples such as specific surface area, pore volume, and pore size distribution was studied. Supercapacitor capability of materials was investigated in 1 mol L-1 Na2SO4 solution using cyclic voltammetry in different potential scan rates and electrochemical impedance spectroscopy (EIS). The specific capacitance of materials was calculated, and it was observed that the specific capacitance of PANI/MnCo2O4 nanocomposite was 185 F g−1, much larger than PANI. Moreover, the prepared nanocomposite exhibited better rate capability in scan rate of 100 mV s−1 with respect to PANI. The EIS experiments revealed that the nanocomposite has lower charge transfer resistance compared with pure PANI. Subsequently, it was shown that the nanocomposite cycling performance was superior to the PANI cycling performance. [ABSTRACT FROM AUTHOR]