Volume 78, Issue 8

Due to nonlocal and strain gradient effects with rigid and deformable boundary conditions, the thermal vibration behavior of perforated nanobeams resting on a Winkler elastic foundation (WEF) is examined in this paper. The Stokes transformation and Fourier series have been used to achieve this goal and to determine the thermal vibration behavior under various boundary conditions, including deformable and non-deformable ones. The perforated nanobeams’ boundary conditions are considered deformable, and the nonlocal strain gradient theory accounts for the size dependency. The problem is modeled as an eigenvalue problem. The effect of parameters such as the number of holes, elastic foundation, nonlocal and strain gradient, deformable boundaries and size on the solution is considered. The effects of various parameters, such as the length of the perforated beam, number of holes, filling ratio, thermal effect parameter, small-scale parameters and foundation parameter, on the thermal vibration behavior of the perforated nanobeam, are then illustrated using a set of numerical examples. As a result of the analysis, it was determined that the vibration frequency of the nanobeam was most affected by the changes in the dimensionless WEF parameter in the first mode and the changes in the internal length parameter when all modes were considered.

In this paper, the perturbed Gerdjikov–Ivanov equation with spatio-temporal dispersion is investigated. The trial equation method, the complex envelope travelling wave transformation, and the complete discriminant system for polynomial method, respectively, are all utilized. As a consequence, twenty-eight exact chirped solutions are obtained, and some representative two-dimensional patterns under concrete parameters are presented. The results acquired are conducive to studying the dynamic behavior of solitons.

This work demonstrates the study of the optimal system of solutions for shock wave propagation in a non-ideal self-gravitating gas in rotating medium with magnetic field (axial or azimuthal) for the adiabatic flow in cylindrical geometry by applying the group invariance technique. Using the group invariance technique, we have obtained the one-dimensional (1-D) optimal system of sub-algebra for the basic governing equations. The infinitesimal group optimal classes are obtained and the similarity solution in four possible cases (two cases for perfect gas and two cases for non-ideal gas) with exponential law shock path are discussed. The numerical solution by using the Runge Kutta 4th order method is obtained and the distribution of physical variables are shown via graph. The impact of the rotational parameter, non-idealness parameter, shock Cowling number, similarity exponent and gravitational parameter on the strength of the shock and flow variables are investigated. With an increase in the shock Cowling number, non-idealness and rotational parameters, the shock strength decreases, i.e., they have decaying impact on shock wave; whereas the shock strength increases with gravitational parameter and similarity exponent. Also, the strength of the shock is reduced by considering the magnetic field to be axial instead of azimuthal.

This article discusses a mathematical model for the electrokinetic and Darcy’s resistance of Williamson fluid in an electroosmotic pumping environment. The zeta potential at walls aids in peristaltic movement, and porous dissipation is incorporated into this modulation by the Williamson fluid’s material parameters. Through the use of Debye-Huckel approximations, long wavelengths, and low Reynolds numbers, the model equations are simplified. Mathematica software is used to produce analytical and numerical results, and plots and analyses are done using the included parameters on physical quantities of interest. This study has various practical applications, such as modifying belt resistance in laboratory drainage testing and improving pipeline design. It could also potentially aid in the development of blood filtration and purification techniques and optimize drug delivery systems that utilize fluids. It is observed that the modified Darcy’s law is more accurate for porosity effects in electroosmotic peristaltic channels and results in higher shear stress at the channel wall compared to Darcy’s law.

ZnO nanoparticles doped with Co at different concentration (Zn 1− x Co x O) were synthesized by sol–gel auto combustion method and are characterized by using various characterization tools. Structural study using X-ray diffraction technique (XRD) analysis showed the crystalline nature with hexagonal wurtzite geometry and the composition analysis using energy dispersive X-ray spectroscopy (EDX) confirmed the incorporation of Co in the ZnO lattice in the case of doped nanoparticles. Scanning electron-microscopy (SEM) and transmission electron microscopy (TEM) analysis showed the prepared nanoparticles as spherical, loosely agglomerated and having dimension of nanoscale. UV–vis DRS studies indicated a red shift in optical band gap with Co doping. PL spectra exhibits emission in the UV and visible region and the analysis revealed information about the presence of various types of defects in the ZnO lattice. An increase in the excitation wavelength gives intense emission in the high wavelength region for doped nanoparticles confirming the presence of divalent and monovalent oxygen as main defects. The Zn 0.93 Co 0.07 O nanoparticles records CIE coordinates lying in the white region of CIE color space at 350 nm with CCT of 5561.4 K suggesting their suitability in fabrication of white light emitting diodes.

A blue emitter of Er 3+ ions doped a host glass of a chemical composition 30B 2 O 3 –30Bi 2 O 3 –20Li 2 O–10BaO–10PbO was fabricated to be used in optoelectronics devices. Four proposed concentrations of Er 2 O 3 , which are 0.5, 1, 2, and 4 mol%, were suggested to study the impact of Er 3+ ions on the structural, thermal, and photoluminescence properties of the considered host glass, respectively. The phase checking of the produced glasses using X-ray diffraction patterns showed the amorphicity phase formation. Impact of Er 3+ ions on the structural properties of the considered host glass network was extensively studied through the occurred variations in XRD patterns, density and density-based parameters, and FTIR spectra. Thermally, the considered glasses have high thermal stability and high glass formability. Optically, the optical band gap, which ranged between 2.18 and 2.56 eV, signifies that the considered glasses have a semiconducting nature. Under 540 nm excitation wavelength, three bands were emitted in the blue region at 450, 462, and 486 nm and two in the violet region at 412 and 427 nm. Chromaticity analysis through CIE 1931 chromaticity diagram showed a strong blue light emission from the produced glasses. The blue light color purity of the considered glasses ranged between 90.887 and 92.324 %. Hence, the considered glasses have suitable characteristics that make them a good choice as blue light-emitting diodes in the optoelectronics devices.