Modern Physics Letters B

Based on first-principles, this paper calculates the structure, electrical properties and optical properties of g-GaN/AlGaN 2D/3D heterojunctions with different Al contents. By comparing the binding energies of different Al contents, it can be concluded that the structure of heterojunction is the most stable when the Al content is 0.5. The band gap of heterojunction widens as the Al content increases. When the Al content is 1, the band structure changes from direct band gap to indirect. Through the study of density of states, it can be found that impurity levels near the Fermi level mainly come from electronic states of N 2p, Al 3p, and Ga 4p. The appearance of impurity levels makes it easier to recombine the electron hole pairs in the heterojunction. The results of optical properties indicate that the heterojunction exhibits better wave absorption performance with the increase of Al content and is more conducive to the propagation of photoelectrons.

In this study, a three-point bending test was carried out to determine the mechanical properties of hexagonal-shaped honeycomb core sandwich panels made of jute yarn with two distinct fiber orientations. A custom-made handloom was used to weave the unidirectional jute mat, and hand-layup with the cold press process was applied to fabricate the hexagonal honeycomb sandwich panel. To explore the effectiveness of different natural fibers for producing honeycomb core sandwich panels, a Finite Element Method (FEM) analysis was performed on different natural fibers with different fiber orientations. The resistance to environmental deterioration of bending properties was also investigated. Overall, this work offers perceptive information about the mechanical characteristics of sandwich panels made of jute honeycomb core and their behavior under various climatic circumstances, which may be relevant in a variety of engineering applications. Finally, it is noteworthy that the mechanical properties of jute fibers are anisotropic, which implies that their strength varies with the direction of loading. Sandwich panels with horizontal fiber orientation of hexagonal honeycomb core withstand a 36% higher bending strength than those with vertical fiber orientation.

The recent applications in industrial products and engineering need high thermal efficiency for the betterment of the shape of the products, the concept of hybrid nanofluid is significant in comparison to nanofluid and pure fluid. Therefore, this analysis focuses on the flow of a micropolar hybrid nanofluid over a vertical permeable plate. The study considers free convection of an electrically conducting fluid, incorporating metal and oxide components with a water-based hybrid nanofluid. Further, the conjunction of dissipative and radiating heat with generative/absorptive heat enhances the thermal properties. The use of standard transformation rules gives rise to converting the nondimensional form of concerned PDEs to ODEs. Moreover to get rid of the solution, for the nondimensional set of equations, a shooting-based numerical technique like Runge–Kutta (RK)-fourth-order is adopted for the standard values of several components within their range. The effectiveness of these parameters is studied and displayed through graphs. The computed result of the rate coefficients at the surface is depicted in tabular form. The comparative analysis with earlier work studied by considering the base liquid shows a good correlation in particular cases. However, the important outcomes are, the magnetized nano as well as hybrid nanoparticles produces a thicker momentum boundary layer thickness whereas it enhances the fluid temperature.

The combined heat and mass transfer, the so-called thermosolutal convective problem, has become an attractive field of research in many diversified areas. In this paper, for the first time, oscillatory flow analysis has been carried out for triple diffusive viscoelastic fluid flow in a porous medium. A comprehensive model is developed for the modified Darcy–Brinkman–Oldroyd-B fluid, porous medium, Boussinesq approximation, heat and mass transfer across a finite temperature and concentration difference in the chemical potential of two salts. Triple diffusive viscoelastic fluid flows through porous media have grown significantly as this situation occurs in more than a few applications such as improved oil recovery filtration, liquid complex molding, solidification of liquid crystals, cooling of metallic plate in a bath, exotic lubricants and colloidal solutions, polymer processing, chemical and bioengineering industries, among others. The governing coupled nonlinear partial differential equations with boundary constraints represent the modeled flow problem. In addition, these equations are converted into non-dimensional form by employing suitable non-dimensionalizing quantities. The impacts of the pertinent parameters and related dimensionless numbers on the dimensionless velocity, temperature, concentrations, shear stress, heat and mass transfer are examined for both suction and injection cases. It has been found that when the injection level on the heated plate is increased, the shear rate increases for each channel plate. Furthermore, we recognized that the viscoelastic parameters exhibit an opposite kind of behavior on the velocity, temperature, and concentrations fields.

The significance of hybrid nanofluid flow over a flat plate lies in its ability to enhance heat transfer, improve energy efficiency, enable temperature control, and provide surface protection. For instance, hybrid nanofluids can provide a protective coating on the surface of a flat plate due to the presence of nanoparticles. This coating can offer improved corrosion resistance, erosion resistance, and anti-fouling properties. Consequently, it can extend the lifespan of the flat plate and reduce maintenance requirements. In this study, we examined how several characteristics, such as variable viscosity, chemical reaction, thermal radiation and shape factor of nanoparticles, affect the flow of a hybrid nanofluid (H${}_2\mathrm{\text{O}}+\mathrm{\text{MWCNT}}+\mathrm{\text{CuO}}$) through a flat plate. The equations required to represent the problem have been turned into a system of nonlinear ordinary differential equations, and this system has been unraveled by means of the bvp4c solver. Outcomes are provided for three instances related to shape factor i.e. Platelet, Cylinder and Spherical. Using Multiple Linear Regression (MLR), we investigated how physical parameters of concern together with friction factor, are affected by a variety of parameters. It is remarked that the fluid’s velocity lessens as the variable viscosity parameter enhances. It is discovered that the temperature profile increases with the rise in exponential heat source parameter ($Qe$). It is discovered that when $0.1\le Qe\le 2.5$, the Nusselt number declines by 0.03588 (Platelet shape), 0.03562 (Cylinder shape), and 0.03489 (Spherical shape). It has been noted that magnetic field parameter (Mg) reduces the coefficient of skin friction. At $0\le \mathrm{\text{Mg}}\le 3$, the skin friction coefficient is seen to drop at a rate of 1.15018 (Platelet shape), 1.14871 (Cylinder shape), and 1.14476 (Spherical shape). There is an enhancement in the Sherwood number with the rise in Schmidt number (St) and chemical reaction parameter (Cr). At $0.1\le \mathrm{\text{Cr}}\le 1.3,$ the Sherwood number is seen to rise at a rate of 0.248303 (Platelet shape), 0.248344 (Cylinder shape), and 0.248447 (Spherical shape). Furthermore, it is detected that the fluid’s temperature rises as the thermal radiation parameter enhances and the entropy generation increases as the variable viscosity parameter increases.

The growing popularity of artificial intelligence approaches has led to their application in a wide range of engineering fields. The most widely used artificial intelligence tool, artificial neural networks, can be used to predict data with high accuracy. An artificial neural network approach is being used to predict effective and accurate thermal conductivity and viscosity models for hybrid nanofluid systems. Here, new types of correlations relating to the thermophysical properties of Fly Ash–Cu nanoparticles with diameter sized 15.2nm and which are temperature-dependent are developed. The highest thermal conductivity and viscosity values were obtained for hybrid nanofluids with a mixture ratio of 20:80, with maximum amplification exceeding 83.2% and 65%, respectively, over the base fluid. The Fly Ash–Cu/water hybrid nanofluid’s viscosity and thermal conductivity are evaluated for a concentration range of 0–4%. The evaluation of the Fly Ash–Cu/water hybrid nanofluids system at concentrations ranging from 0 to 4% most likely entails a scientific or engineering study aimed at understanding the behavior and properties of this nanofluid mixture. Nanoparticles can agglomerate or settle in the base fluid over time, compromising the stability of the nanofluids. Researchers may be interested in determining how varied quantities of Fly Ash and Cu nanoparticles affect the nanofluid’s stability and sedimentation behavior. The heat transfer potential is examined within the optimistic range of temperatures of 30–80^∘C. Many fruitful results for turbulence and solar energy have been drawn. The Mouromtseff number achieved an optimal value for all concentration levels. The heat transfers of turbulent flow and thermal conductivity of hybrid nanofluids increase with the augmented values of concentrations and temperature. Researchers found an increase in thermal conductivity of hybrid nanofluids at 0–4% concentrations, potentially impacting heat transfer applications. The conclusion explores the potential integration of the developed correlations and neural network model into practical engineering or industrial applications involving solar energy and turbulence appliances. In this work, we extend the work of Kanti et al. [Sol. Energy Mater. Sol. Cells 234 (2022) 111423] which is on the properties of water-based fly ash-copper hybrid nanofluid for solar energy applications.

In this paper, the adsorption behavior of intrinsic black phosphorus (BP) and BP doped with five atoms of O, Si, S, Cu and Zn on Pb${}^{2+}$ in aqueous solution was investigated by using the first principle of nature. The formation energy was calculated to be the smallest for Si-doped BP at 2.608eV, indicating the best structural stability. The adsorption energy was calculated and showed that the doped BP is more capable of adsorbing Pb${}^{2+}$ than the intrinsic BP, with the S-doped BP having the strongest adsorption capacity of 0.151eV. The density of states was calculated and showed that the bandgaps of the doped BP are all smaller than the 1.3eV of the intrinsic BP, indicating that the doping can improve electrical conductivity of the adsorption system. The charge transfer was calculated and showed that S doping, O doping, Cu doping and Zn doping enhanced the ionic bonding between BP surface atoms and Pb${}^{2+}$, while Si doping weakened the ionic bonding. The charge transfer of S doping was the largest at 1.371e, indicating that S-doped BP had the strongest ability to adsorb Pb${}^{2+}$.

We present a new design of three photonic crystal fibers (PCFs) made of fused silica glass, infiltrated with toluene (C₇H₈) with different lattices in cladding including circular lattice (CL), hexagonal lattice (HL) and square lattice (SL). The optimal structures that operate in the all-normal dispersion regime, were selected by investigating the dependence of the lattice parameters in the first ring surrounding the core on the PCF characteristics. In addition, we punctuate the possibility of coherent octave-wide supercontinuum (SC) generation in the wavelength range of 0.75–1.68$\mu$m, 0.76–1.91$\mu$m (1.3$\mu$m pump wavelength), and 0.65–1.45$\mu$m (1.064$\mu$m pump wavelength) with 90fs pulses and 30pJ of low energy in-coupled into the core of the selected PCFs. The highest SC generation efficiency is obtained with HL-PCF. The proposed fibers are good candidates for all-fiber SC sources, as a new source of SC light.

This study employs density functional theory (DFT) calculations to investigate the impact of tantalum (Ta) doping in ZnSnO₃ to investigate the electronic and optoelectronic properties. ZnSnO₃ is a promising semiconductor material with a wide bandgap and visible light transparency, making it suitable for optoelectronic applications. However, its low electrical conductivity limits its performance in these applications. The results revealed that our structural parameters are in good agreement with the experimental values. The electronic structures revealed that the top of the valence band and the bottom of the conduction band are decided by O 2p and Sn 5s states, respectively, and that ZnSn${}_{1-x}$Ta_xO₃ presented a direct band gap (1.0eV) located at $\mathrm{\Gamma }$-point. Finally, the complex dielectric function and optical constants (such as absorption spectrum, refractive index, extinction coefficient, reflectivity, and energy-loss spectrum) were obtained and discussed in detail. Our findings also suggested that ZnSn${}_{1-x}$Ta_xO₃ is a promising transparent semiconductor and photocatalyst. These insights provide opportunities for high-performance optoelectronic device design such as biomedical and LED.

In this work, we study a ($2+1$)-dimensional variable-coefficient Caudrey–Dodd–Gibbon–Kotera–Sawada equation in fluid mechanics. The new lump and lump-soliton solutions are obtained by the variable-coefficient polynomial function method. We used 3D graphs, contour plots and density graphs to show that the amplitude and velocity of solitons are affected by some variable coefficients. It is proved that the polynomial function method with variable coefficients is very direct and effective for solving lump-type solutions in variable coefficient integrable systems, and more new conclusions can be obtained.

Mechanical metamaterials are valued for their diverse properties and potential applications. Due to the instability and large deformability of soft mechanical metamaterials (SMMs), geometric reorganization will occur and lead to some unusual properties. It is possible to change the properties of materials by varying the parameters. Conventional SMMs contain a periodic distribution of holes with the same size and shape, which can be changed to a lesser extent. Periodic dispersion of regular through-hole patterns of various sizes or shapes into elastomers, resulting in metamaterials with more mechanical functionality and deformation scenarios. In this paper, we investigated the influence of parameters on the buckling mechanical behavior of SMMs and the buckling mechanical behavior of structures with multiple sizes and geometric shapes. The parameters studied include geometric parameters (pore shape, porosity and area ratio) and physical parameters (Poisson’s ratio and compression mode). Simulation of the buckling behavior of SMMs uses the finite element method. The finite element software ABAQUS is used, taking into account the almost incompressible characteristics of materials, the triangular quadratic plane strain hybrid element is selected (CPE6H). Numerical calculation gives the following results: Area ratio, pore shape and compression mode have obvious effects on buckling behavior, but Poisson’s ratio has little effect; the influence of parameters on the buckling critical strains varied for SMMs with various pore shapes; very different buckling behaviors will result from swapping out the pattern of holes with the same size or shape for holes with two different sizes or shapes; the expression of buckling behavior is also varied when the mix of hole shapes is modified. These findings demonstrate that the design parameters may be used to achieve the desired buckling behaviors. This is a new method that can be used to control the deformation of structures; modify the properties of the SMMs without changing stiffness; simplify the structures without significantly changing the material properties. The design path of mechanical metamaterials is increased.

The current theoretical analysis reports the flow and heat transfer rate in the peristaltic flow of an Ellis fluid through the complex wavy divergent channel under the impact of the electro-osmotic phenomena and viscous dissipation. The governing equations of the current flow are based on the continuity equation, Cauchy’s momentum equations, Poisson–Boltzmann equation, and the heat equation. The momentum equation is updated with the addition of the Poisson equation to introduce the electro-osmotic effects on the given flow field. The energy equation is upgraded under the addition of the viscous dissipation term to capture the effects of the Brinkman number. The Poisson equation is linearized by adopting the Debye–Hückel approximation. The problem is transformed into a dimensionless form and solved analytically to present the analytical solution of the current flow problem. The analytical expression of longitudinal velocity, temperature field, and stream function is presented by using the symbolic mathematical software MATHEMATICA 12.0. The computational results reveal that the heat transfer rate is strongly affected by the power law index $\alpha$ and dimensionless material parameter $\beta$. The longitudinal velocity is diminishing against the power law index. The power law index parameter produces the trapping bolus inside the divergent channel for $\alpha >0$.