Browsing by Subject "mechanical properties"

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    Electronic and atomic processes in nanowires
    (1996) Mehrez, Hatem
    The variation of conductance of a nanowire which is pulled between two metal electrodes has been the subject of dispute. Recent experimental set-ups using a combination of STM and AFM show that changes in conductivity are closely related with modification of atomic structure. In this thesis electron transport in the nanoindentation and in the connective neck are studied and features of measured conductance are analyzed. Molecular Dynamics simulations of nanowires under tensile stress are carried out to reveal the mechanical properties in nanowires in the course of stretching. A novel type of plcistic deformation, which leads to the formation of bundles with “giant” yield strength is found. An extensive analysis on how abrupt changes in the conductance and the last plateau before the break are related with “quantization phenomena” and atomic structure rearrangements in the neck. By using ab-initio self-consistent field pseudopotential calculations we also investigated electron properties of nanowires and atomic chains and predicted the large yield strength observed in the center of connective neck.
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    Improved mechanical properties of the E-glass fibres through TiO2 nanoparticle coating
    (Taylor & Francis, 2023-07-01) Ahmed, Md Kawsar; Behboud, Ali Bagheri; Kurucu, Arda; Kurt Çömlekçi, Göksenin; Ordu, Mustafa
    In this work, the mechanical properties of nanoparticle-coated E-glass fibres were investigated for high-performance composites. Glass fibres were dip-coated in TiO2 solutions by varying the concentration of nanoparticles. Single-filament tensile test was performed on bare and coated fibres to understand the effects of nanoparticles and the concentration of solutions on the mechanical properties. The analysis was carried out using two-parametrical Weibull distribution, and the result indicates that the nanoparticle-coated glass fibres have a lower probability of failure than the bare fibres. The tensile strengths of the fibres were improved up to 7.31%, 11.71% and 9.67% by coating with 5%, 10% and 15% nanoparticle solutions, respectively. The nanoparticle-coating of glass fibres has positively affected the mechanical properties against fabrication-related surface defects.
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    Structural, elastic, and electronic properties of topological insulators: Sb2Te3 and Bi2Te3
    (IEEE, 2013) Koc H.; Mamedov, Amirullah M.; Özbay, Ekmel
    We have performed a first principles study of structural, elastic, and electronic properties of rhombohedral Sb2Te3 and Bi 2Te3 compounds using the density functional theory within the local density approximation. The lattice parameters of considered compounds have been calculated. The second-order elastic constants have been calculated, and the other related quantities such as the Young's modulus, shear modulus, Poisson's ratio, anisotropy factor, sound velocities, and Debye temperature have also been estimated in the present work. The calculated electronic band structure shows that Sb2Te3 and Bi2Te 3 compounds have a direct forbidden band gap. Our structural estimation and some other results are in agreement with the available experimental and theoretical data. © 2013 IEEE.