24 research outputs found

    Wpływ stresu termicznego na uszkodzenie warstwy międzyfazowej kompozytu włóknistego z zastosowaniem algorytmu genetycznego

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    The aim of this paper is to develop an analytical model to evaluate the influence of thermal stress on damage to the fiber-matrix interface of a composite T300/914 from the properties of the fibre, as well as from the matrix and characteristics of the interfacial binding. The model developed by a genetic algorithm takes into account the temperature effects that result in the progressive degradation of the fibre-matrix. This work shows the influence of thermal stress beyond the critical threshold of damage to the interface, and that the matrix damage has an important influence on the damage to the interface compared to that of the fiber.Celem badań było opracowanie modelu analitycznego do oceny wpływu stresu termicznego na uszkodzenia warstwy międzyfazowej kompozytu T300/914 na podstawie właściwości włókien i matrycy oraz charakterystyki połączenia. Model opracowany przez algorytm genetyczny uwzględnia wpływ temperatury, który prowadzi do degradacji matrycy. Artykuł opisuje również wpływ stresu termicznego w warunkach krytycznych

    The Doping Effect on Ferromagnetic Arrangement and Electronic Structure of Cubic AlAs with Low Concentration of 3d (V, Cr, and Mn) Impurities

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    The doping effect of aluminum arsenide (AlAs) with 3d (TM = V, Cr, and Mn) of transition metal impurities gives new materials called diluted magnetic semiconductors, which have interesting electronic and magnetic properties for spintronics applications. We have used the full-potential linearized augmented plane wave (FP-LAPW) method to calculate the electronic band structures and magnetic properties of Al1−xTMxAs at low concentration x = 0.0625 of transition metal (TM = V, Cr, and Mn) atoms. We have found that the majority-spin states of Al0.9375TM 0.0625As compounds are metallic due to large p-d hybridization between 3d levels of TM and the 4p levels of As around Fermi level, whereas the minority-spin states have semiconductor character. These compounds exhibit a half-metallic behavior with spin polarization of 100%, where the ferromagnetism is originated from double-exchange mechanism. Therefore, Al0.9375TM0.0625As (TM = V, Cr, and Mn) materials seem to be good candidates for spin injection in the field of spintronics applications

    Zn-Al LDH growth on AA2024 and zinc and their intercalation with chloride: Comparison of crystal structure and kinetics

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    The dissimilarities and features of the crystal structure of ZnAl LDH-NO3 conversion layers grown directly on pure zinc and aluminum alloy 2024 were investigated in the present paper. Although the nature of the cations in the double hydroxides are the same in both cases (Al3+ and Zn2+), their sources differ according to the substrate. This leads to a difference in the cationic layers and interlayer structure, which consequently influences the anionic exchange reaction. In the frame of this work, the kinetics of the anion-exchange of nitrate by chloride was investigated as well as the crystal structure of the resulting ZnAl LDH-Cl on both substrates. Synchrotron high-resolution X-ray diffraction was the main method to obtain structural information and was supported by additional calculations and scanning electron microscopy.The current study revealed noticeable changes on the positioning of the interlayer atoms for the ZnAl-LDH-Cl on zinc in comparison with the ones on AA2024 substrate
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