Abstract
We have studied the structural and optical properties of the non-doped and Co 0.08 at.%, Co 0.02 at.%, and Co 0.11 at.% doped ZnO nanorods (NRs) synthesized using the simple low-temperature chemical bath deposition (CBD) method at 95oC for 2 hours. The scanning electron microscope (SEM) images confirmed the morphology of the ZnO NRs are affected by Co incorporation. As observed, the Co 0.08 at.% doped ZnO NRs have a larger dimension with an average diameter of 153.4 nm. According to the International Centre for Diffraction Data (ICDD) number #00-036-1451, the x-ray diffraction (XRD) pattern of non-doped and Co-doped ZnO NRs with the
preferred orientation of ZnO NRs in the (002) plane possess polycrystalline hexagonal wurtzite structure with the space group P63mc. Optical absorbance indicates the Co 0.08 at.% doped ZnO NRs have stronger and blueshift bandgap energy (3.104 ev). The room temperature photoluminescence (PL) spectra of ZnO NRs exhibited excitonicrelates ultraviolet (UV) and defect-related green band (GB) emissions. By calculating the UV/GB intensity, the Co 0.08 at.% is the proper atomic percentage to have fewer intrinsic defects. We predict that Co-doped ZnO NRs induce a blueshift of near band edge (NBE) emission due to the Burstein-Moss effect. Meanwhile, the redshift of NBE emission is attributed to the modification of the lattice dimensions and exchange energy.
Address
Iwan Sugihartono, Novan Purwanto, Desy Mekarsari: Program Studi Fisika, FMIPA Universitas Negeri Jakarta, Jl. Rawamangun Muka, Jakarta Timur 13220, Indonesia
Isnaeni: National Research and Innovation Agency, KST BJ Habibie, South Tangerang, 15314 Indonesia
Markus Diantoro: Department of Physics, State University of Malang, Jl. Semarang No 5, Malang 65145, Indonesia
Riser Fahdiran: Program Studi Fisika, FMIPA Universitas Negeri Jakarta, Jl. Rawamangun Muka, Jakarta Timur 13220, Indonesia
Yoga Divayana: Department of Electrical Engineering, Udayana University, Kampus Bukit Jimbaran, Bali 80361, Indonesia
Anggara Budi Susila: Program Studi Fisika, FMIPA Universitas Negeri Jakarta, Jl. Rawamangun Muka, Jakarta Timur 13220, Indonesia
Abstract
This paper aims to analyze the dynamic response of a double nanobeam system with a medium viscoelastic layer under a moving load. The governing equations are based on the Eringen nonlocal theory. A thin viscoelastic layer has coupled two nanobeams together. An exact solution is derived for each nanobeam, and the dynamic deflection is achieved. The effect of parameters such as nonlocal parameter, velocity of moving load, spring coefficient and the viscoelastic layer damping ratio was studied. The results showed that the effect of the nonlocal parameter is significantly important and the classical theories are not suitable for nano and microstructures.
Address
S.A.H. Hosseini: Buein Zahra Technical University, Buein Zahra, Qazvin, Iran
O. Rahmani: Smart Structures and New Advanced Materials Laboratory, Department of Mechanical Engineering, University of Zanjan, Zanjan, Iran
H. Hayati: Faculty of Engineering and Information Technology, University of Technology Sydney, PO Box 123 Broadway, Ultimo, NSW 2007, Australia
M. Keshtkar:1Buein Zahra Technical University, Buein Zahra, Qazvin, Iran
Abstract
The present work is considered to study the two-dimensional problem in an orthotropic magnetothermoelastic media and examined the effect of thermal phase-lags and GN-theories on Rayleigh waves in the light of fractional order theory with combined effect of rotation and hall current. The boundary conditions are used to derive the secular equations of Rayleigh waves. The wave properties such as phase velocity, attenuation coefficient are computed numerically. The numerical simulated results are presented graphically to show the effect of phase-lags and GN-theories on the Rayleigh wave phase velocity, attenuation coefficient, stress components and temperature change. Some particular cases are also discussed in the present investigation.
Key Words
attenuation coefficient; fractional order; hall current; orthotropic; phase lags; phase velocity; Rayleigh wave propagation; rotation
Address
Parveen Lata and Himanshi: Department of Mathematics, Punjabi University, Patiala, Punjab, India
Abstract
Polyester composites play a vital role in civil engineering applications, especially in bridge and car park structures. Therefore, the addition of waste silica-based fillers will both improve the mechanical and durability performance of composites and produce an environmentally friendly material. In this study, the mechanical performance of polyester composites was investigated experimentally and numerically by adding micro and nanosized silica-based fillers, marble powder, silica fume and nano-silica. 24 cubes for the compression test and 18 prisms for the flexural test were produced in six different groups containing 30% marble powder, 5% silica fume and 1% nano-silica by weight. SEM/EDS testing was used to investigate the distribution of filler particles in the matrix. Experimentally collected results were used to validate tests in the Abaqus software. Additionally, the Extended Finite Element Method (XFEM) was used to estimate the fracture process for the flexural test. The results show that the added silica fume, marble powder and nano silica improves the compressive strength of polyester composites by 32-38% and the flexural tensile strength by 10-60% compared to pure polyester composite. The numerically obtained results matched well with the experimental data, demonstrating the accuracy and feasibility of the calibrated finite element model.
Key Words
crack propagation; FEM; mechanical properties; polyester composites; SEM/EDX
Address
Ibrahim Alameri: Department of Civil Engineering, Faculty of Engineering, Sana'a University, Sana'a, Yemen
Meral Oltulu: Department of Civil Engineering, Faculty of Engineering, Ataturk University, Erzurum, Turkey
Abstract
This study aims to analyze the mechanical buckling behavior of a single-walled carbon nanotube
(SWCNT) integrated with a one-parameter elastic medium and modeled as a Kerr-type foundation under a longitudinal
magnetic field. The structure is considered homogeneous and therefore modeled utilizing the nonlocal first shear
deformation theory (NL-FSDT). This model targets thin and thick structures and considers the effect of the transverse
shear deformation and small-scale effect. The Kerr model describes the elastic matrix, which takes into account the
transverse shear strain and normal pressure. Using the nonlocal elastic theory and taking into account the Lorentz
magnetic force acquired from Maxwell relations, the stability equation for buckling analysis of a simply supported
SWCNT under a longitudinal magnetic field is obtained. Moreover, the mechanical buckling load behavior with
respect to the impacts of the magnetic field and the elastic medium parameters considering the nonlocal parameter, the
rotary inertia, and transverse shear deformation was examined and discussed. This study showed useful results that can
be used for the design of nano-transistors that use the buckling properties of single-wall carbon nanotubes (CNTs) due
to the creation of the magnetic field effect.
Key Words
carbon nanotube; Kerr
Address
Belkacem Selmoune, Abdelwahed Semmah: Department of Physics, University of Relizane, Algeria; Multiscale Modeling and Simulation Laboratory, Department of Physics, Faculty of Exact Sciences, Department of Physics, University of Sidi Bel Abbés, Algeria
Mohammed L. Bouchareb: Multiscale Modeling and Simulation Laboratory, Department of Physics, Faculty of Exact Sciences, Department of Physics, University of Sidi Bel Abbés, Algeria
Fouad Bourada: Material and Hydrology Laboratory, Civil Engineering Department, Faculty of Technology, University of Sidi Bel Abbes, Algeria; Science and Technology Department, Faculty of Science and Technology, Tissemsilt University, Algeria
Abdelouahed Tounsi: Material and Hydrology Laboratory, Civil Engineering Department, Faculty of Technology, University of Sidi Bel Abbes, Algeria; YFL (Yonsei Frontier Lab.), Yonsei University, Seoul, Korea; Department of Civil and Environmental Engineering, King Fahd University of Petroleum & Minerals, 31261 Dhahran, Eastern Province, Saudi Arabia
Mohammed A. Al-Ostas: Department of Civil and Environmental Engineering, King Fahd University of Petroleum & Minerals,
31261 Dhahran, Eastern Province, Saudi Arabia; Interdisciplinary Research Center for Construction and Building Materials, KFUPM, 31261 Dhahran, Saudi Arabia
