فهرست مقالات Elastic Moduli

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  1 - Elastic moduli of some rare-earth doped tellurite glasses
  Raouf El-Mallawany Samir A. Yousef Abdelhamid El-Shaer Hanan A. Elabd
  10.57647/J.JTAP.2023.1705.47
  Samarium oxide (Sm2O3) and ytterbium oxide (Yb2O3) doped tungsten-tellurite glasses (TWSm), (TWYb) in the forms of 80 (TeO2) - (20-x) (WO3) - x (Sm2O3) and 80 (TeO2) - (20-x) (WO3) - x (Yb2O3) with x = 0, 1.0, 2.0, 3.0, 4.0 and 5.0 mol% were prepared by the melt-quenchi چکیده کامل

  Samarium oxide (Sm2O3) and ytterbium oxide (Yb2O3) doped tungsten-tellurite glasses (TWSm), (TWYb) in the forms of 80 (TeO2) - (20-x) (WO3) - x (Sm2O3) and 80 (TeO2) - (20-x) (WO3) - x (Yb2O3) with x = 0, 1.0, 2.0, 3.0, 4.0 and 5.0 mol% were prepared by the melt-quenching technique. The XRD analysis for the two prepared glass systems verified the samples’ amorphous nature. The glass density ( ρ ) was measured by the Archimedes method. Both ( ρ ) and the molar volume (VM) of the two prepared systems showed an increase with increasing the concentrations of dopants Sm3+ and Yb3+. Longitudinal VL and shear VS wave velocities were measured at 5 MHz frequency using the pulse-echo technique. Longitudinal (L), shear (G), bulk (K), and Young’s moduli ( E ) have been founded. Moreover, Poisson’s (σ), Debye temperature (θD), softening temperature (TS), micro-hardness (H) have been founded for every glass sample. Elastic moduli showed an increase with increasing dopants concentration of (Sm2O3) or (Yb2O3). Moreover, the bulk modulus of (TWSm) glasses was higher than (TWYb) glasses. Mechanical properties of (TWSm) and (TWYb) are crucial parameter in manufacturing optical fibers. پرونده مقاله
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  2 - Molecular Dynamics Investigation of The Elastic Constants and Moduli of Single Walled Carbon Nanotubes
  Mohammad Mahdi Zaeri Saeed Ziaei-Rad
  10.22034/jna.2017.01.008
  Determination of the mechanical properties of carbon nanotubes is an essential step in their applications from macroscopic composites to nano-electro-mechanical systems. In this paper we report the results of a series of molecular dynamics simulations carried out to pre چکیده کامل

  Determination of the mechanical properties of carbon nanotubes is an essential step in their applications from macroscopic composites to nano-electro-mechanical systems. In this paper we report the results of a series of molecular dynamics simulations carried out to predict the elastic constants, i.e. the elements of the stiffness tensor, and the elastic moduli, namely the Young’s and shear moduli, of various single walled carbon nanotubes. Poisson’s ratios were also calculated. Three different methods were used to run the simulations: applying a predetermined strain and reading the resulted stress, applying forces and constraints to the end atoms and calculating the moduli by assuming an equivalent continuum tube, and lastly applying a predetermined stress and reading the consequent deformation. In each case, the effect of nanotube chirality and diameter was studied. In addition, loading conditions were altered in each method to study the effect of nonlinearity of interatomic interactions. The result of the three methods are compared, with each other as well as with the literature, and discussed to obtain reasonable concluding remarks. پرونده مقاله