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This paper aims to investigate the impact of moisture on mechanical properties of insulation paper. According to the molecular modeling approach proposed by Theodorou, the amorphous cellulose models of insulation paper with different moisture contents were built up to calculate mechanical parameters and hydrogen bond networks. And relevant conclusions could be drawn through further analysis on these calculation results: water molecules can destroy hydrogen bond network between the neighboring cellulose molecules, which might be responsible for the significant decrease of Young's modulus and other mechanical parameters, while no appreciable effect of intramolecular hydrogen bonds on mechanical properties was detected. Thus tensile tests were also carried out to study the moisture influence on the Young's modulus, by which the result of the simulation was approved. [ABSTRACT FROM AUTHOR]

The bending and impacting characteristics of sandwich composites containing corrugated paper (CP) as a core layer are discussed herein. The core layer of the sandwich composite was fabricated with CP-reinforced polylactic acid (PLA) resin. The core layer was then stacked with jute fabric and PLA films on the top and bottom surfaces to fabricate the sandwich composites. Two composites [CP-reinforced PLA composite (CP/PLA composite)] and jute fabric/PLA sandwich composite with CP as a core layer [J/PLA/CP composite] were developed in this study. To manufacture the CP/PLA composite core layer, a dipping bath was used for impregnating the paper with a molten PLA solution. The resin film method combined with a hot press was used to produce the jute fabric/PLA/CP sandwich composites. A material test system (MTS810) was used to study the bending properties of the composites. Further, an IZOD impacting instrument was used to examine the impacting characteristics of the composites. Both the CP/PLA and jute fabric/PLA/CP sandwich composites increase the energy absorption capacity in the impact test. [ABSTRACT FROM AUTHOR]

The difficulty of recycling and low photocatalytic efficiency in the visible light significantly limit the use of nano-TiO2 in water pollution control. In this work, Bucky papers (BPs), which play a vital role for adsorption of pollutants and transfer of electrons, are introduced as substrates to fabricate and anchor TiO2 nanorods by a facile hydrothermal method. The photocatalytic properties of the TiO2 and BP composites (TiO2@BP) are studied by photodegrading methylene blue in water solutions. It is found that TiO2@BP possesses four times photocatalytic efficiency for methylene blue of TiO2@Si under ultraviolet light irradiation and 10 times under visible light irradiation. This is considered to be attributed to the synergic effect of TiO2@BP system and surface defects of TiO2 nanorods. The TiO2@BP also shows a stable photocatalytic property even after five cyclic photocatalytic degradation. This study indicates that TiO2@BP is a promising candidate for photocatalytic applications, which provides a reference for further research on synthesis of reusable photocatalysts with higher efficiency. [ABSTRACT FROM AUTHOR]

In this paper, Atomic Force Microscope (AFM) was used to observe the microscopic figure of aged insulation paper in order to analyze the microscopic ageing mechanism of power transformer insulation paper under electrical and thermal stresses. The results indicate that there are obvious concaves and convexes on the surface of aged insulation paper, and the paper samples are punctured because of chain scission and the flow of discharge current, which destroyed the compact cellulose chains structures and the diameter of punctures is about 0.5 nm. In addition, this paper analyzed the influence to the physical chemistry characteristics of insulation paper caused by partial discharge and paper ageing. [ABSTRACT FROM AUTHOR]

The expressions for the pressure dependences of bulk modulus and the Grüneisen parameter used by Arafin and Singh [Int. J. Mod. Phys. B 30, 1750031 (2016)] in the Lindemann law for determining melting curves of 14 alkali halides have been found to yield no results which are consistent with the recent studies on equations of state. It is demonstrated here that Arafin–Singh's expressions are physically not acceptable as they are shown here to give unrealistic values of bulk modulus and Grüneisen parameter for the materials at high pressures. [ABSTRACT FROM AUTHOR]

The degree of polymerization (DP) has been regarded as an important symbol of mechanical strength, reflecting the aging condition of transformer insulation paper. In this article, a new concept called fracture degree is proposed on the basis of DP. First, nine cellulose Iβ crystal models with different fracture degrees were built. Then relevant mechanical parameters and hydrogen bond numbers were calculated by molecular dynamics (MD) simulation. Results showed that during the aging process of insulation paper with fracture of cellulose chain, the elastic constant C33 produces appreciable impact on the Young's modulus (E). With the decrease of DP and increase of fracture degree, the Young's modulus step decreases. To the 50% and 100% fracture degree models respectively, the relationship between their different degrees of polymerization and Young's modulus is subjected to similar exponential distributions. With the increase of the fracture degree, the average hydrogen bond number drops, and the change rules apply to the Young's modulus. Since hydrogen bond is the main factor of mechanical strength, it can be inferred that the fracture degree influences mechanical strength seriously. [ABSTRACT FROM AUTHOR]

The glass transition temperature (Tg) in the amorphous region of an insulation paper is one of the most important characteristics for thermal stability. Molecular dynamic simulations have been performed on three micro-structural models, namely, amorphous pure cellulose, amorphous cellulose with water and amorphous cellulose with oil, to study the microscopic mechanism of the glass transition process for oil-immersed transformer insulation paper. Using the method of specific volume versus temperature curve, the Tg of amorphous pure cellulose, cellulose with water, and cellulose with oil was determined as 448, 418 and 440 K, respectively. The current study may provide some information for thermal aging. The simulation results show that during the glass transition process, both the chain motion and mechanical properties of cellulose changes significantly. Relative to the oil molecules, water molecules immersed in the amorphous region of insulation paper can disrupt hydrogen bonds between cellulose chains. This phenomenon results in a significant reduction in the glass transition temperature and affects the thermal stability of the insulation paper. [ABSTRACT FROM AUTHOR]

The scattering matrix (S-matrix), relating the initial and final states of a physical system undergoing a scattering process, is a fundamental object in quantum mechanics and quantum field theory. The study of factorized S-matrices, in which many-body scattering factorizes into a product of two-body terms to yield an integrable model, has long been considered the domain of mathematical physics. Many beautiful results have been obtained over several decades for integrable models of this kind, with far reaching implications in both mathematics and theoretical physics. The viewpoint that these were only toy models changed dramatically with brilliant experimental advances in realizing low-dimensional quantum many-body systems in the lab. These recent experiments involve both the traditional setting of condensed matter physics and the trapping and cooling of atoms in optical lattices to engineer and study quasi-one-dimensional systems. In some cases the quantum physics of one-dimensional systems is arguably more interesting than their three-dimensional counterparts, because the effect of interactions is more pronounced when atoms are confined to one dimension. This article provides a brief overview of these ongoing developments, which highlight the fundamental importance of integrability. [ABSTRACT FROM AUTHOR]

Numerical unsteady approach based on Galerkin method with the inclusion of adaptive mesh was executed in this paper to simulate the freezing of water within a container. The domain has two triangular and trapezoidal cold surfaces and two adiabatic walls. The governing equations show the domination of conduction and transient source term has been involved. Galerkin method for modeling was applied and good accommodation has been reported based on comparison with previous data. Adding nano-powders makes the amount of heat to be released with stronger conduction and freezing time decreases about 26.76% when m = 8. 6. Augmenting the fraction of powders can make the rate of process increase. For the greatest fraction of powders, an augmenting shape factor can enhance the speed of process about 6.95%. [ABSTRACT FROM AUTHOR]

In this paper, the multi-objective optimization problem (MOOP) of selecting suitable materials from four materials for phononic crystals layouts is investigated based on an optimization method combined nondominated sorting-based genetic algorithm II (NSGA-II) and finite element method (FEM). Driven by different optimization objectives, the changes in the optimized structure compared to the seed structure are the change of the bandgap mechanism from a local resonance mechanism to a Bragg scattering mechanism, the change of the included materials from four to three, and the significant change in the location and extent of the pores and other materials, respectively. The obtained nondominated Pareto solution of MOOP can balance the bandgap and the structural mass, which provides the decision-maker trade-off to select the appropriate optimized solution. Compared with the single-objective optimization problem (SOOP), the MOOP not only obtains a nondominated solution close to the result of SOOP, but also obtains other nondominated solutions of MOOP, which proves the effectiveness of the optimization algorithm in this paper. The design method in this paper can be easily extended to select suitable materials from a wider variety of materials for bandgap optimization design of PnCs, which has very promising applications. [ABSTRACT FROM AUTHOR]

In this paper, we investigate a (3+1)-dimensional integrable fourth-order nonlinear equation that can model both the right- and left-going waves in a fluid. Based on the Hirota method, we derive three sets of the bilinear auto-Bäcklund transformations along with some analytic solutions. Through the extended homoclinic test approach, we obtain some breather solutions. We find that the breather propagates steadily along a straight line, with one hole and one peak in each period. Graphical investigation indicates that the coefficients in that equation affect the location and shape of the breather. Moreover, we construct some mixed lump–kink solutions. Fusion and fission between a lump wave and a kink soliton are analyzed graphically. The solutions addressed in this paper may be applied to mimic some complex waves in fluids. [ABSTRACT FROM AUTHOR]

With a numerical method, the discharging process within a container with a double complex cold surface has been scrutinized in this paper. The inherent process makes conduction as the main mechanism and the temperature equation includes three terms and two of them are time-dependent which was discretized by means of implicit technique. Adding nanoparticles within water can enhance the rate of heat release and concentration of powders and their shapes can affect the properties of nanomaterial. Single phases for estimating the features of nanomaterial were applied. The maximum period of process takes 326.95 s which is 1.36 times lower than the case of pure water. Increasing the shape factor can enhance the speed of process and its impact is less than concentration of additives. [ABSTRACT FROM AUTHOR]

Considerations on the current status of the theory of superconductivity, the bibliometric H-index, and H. C. Andersen's tale about the emperor's new clothes. First appeared in the APS Forum on Physics and Society quarterly newsletter, January 2020. [ABSTRACT FROM AUTHOR]

This paper presents a digital MEMS gyroscope with 40 ∘ /h instability variation in −40 ∘ C to 85 ∘ C, performing 5 ∘ /h instability variation at normal temperature and 0.01% nonlinearity in the range of ±400 ∘ /s. This stability was achieved by using temperature compensation for the zero-output value changed after the temperature signal. As the resonant frequency of the mechanical structure varied according to the temperature linearly, a frequency calculator was adopted to detect the temperature of the mechanical structure. And the resolution of the frequency could be up to 0.01 Hz with a 1 MHz clock frequency used, obtaining a 10 Hz bandwidth. The driving mode used a PI controller to control a VGA to maintain at a fixed effective value of the driving signal. The sensing mode contained a low noise C/V convertor and a switch demodulation, which could give the angular velocity signal to the A/D convertor. Then the output data of A/D will be compensated in the digital domain. Finally, the digital output of the gyroscope will be available through a normal SPI serial port. The whole circuit was realized on one chip with an active circuit area of 3.5 mm × 5.2 mm fabricated in a 0.35  μ m CMOS technology. And the MEMS structure and circuit are packaged in a 2.5 cm × 2.5 cm × 2.5 cm aluminum mold. The digital output of the gyroscope earned a noise floor of 0.0024 ∘ /s. [ABSTRACT FROM AUTHOR]

This paper describes the fundamental characteristics of cavitation in non-Newtonian liquids and bubble dynamics and then applies them to the domains of bioengineering and biomedicine. The goal of this paper is to examine how Newtonian nanomaterial flows hydromagnetically when subjected to a spinning disc considering such biomedical and bioengineering applications. The vertical axis of the disc rotates with a uniform angular frequency. The fundamental mathematical expressions are governed by the Navier–Stokes equations with the Maxwell equations of magnetism, we obtained ordinary differential equations utilizing Von Kármán's similarity transformations. Additionally, the effects of the magnetic field and radiation restrictions are considered. The RK-4 technique is used to solve the transmuted nonlinear ODEs. The analysis of MATLAB generated flow profiles has looked for changes in the values of key parameters. It is discovered that an increase in the thermal radiation parameter causes a decrease in the nanofluid temperature while an increase in the volume fraction of magnetite nanoparticles causes an increase. The skin-friction and heat-transfer rate at the disc are highly influenced by its rotational, the porosity of the porous media, thermal radiation and nanoparticle size. The rotational parameter, which regulates the disk's rotation, is a result of the rotating phenomenon. The research demonstrates that when the disk's rotation increases, the fluid motion accelerates in both the radial and cross-radial directions. Additionally, increasing the Prandtl number significantly improves heat transport, and a higher value for the rotation parameter shows a lesser concentration phenomenon. Additionally, the Nusselt number shows a decrease curve for a changeable thermal conductivity parameter. Finally, the current research can effectively close a gap in the physique of knowledge. [ABSTRACT FROM AUTHOR]

The influence of conjugate heat transfer based on radiation and magnetohydrodynamic utilization is an attractive research area, with progressive features; it has many applications in thermal engineering, heat exchangers, cooling phenomenon, magnetic cell separation, energy production, hyperthermia, etc. Following the motivating significances of the current research topic, this paper explores the influences of an electrically conducting and radiating fluid with internal friction, heat generation and thermal radiation embedded in a porous medium past a flat permeable plate. The boundary layer equations are dimensionally transformed and solved numerically using implicit finite difference technique called the Keller-box method. The effect of various fluid obeying parameters such as magnetic field, viscous dissipation and heat generation on the flow factors such as velocity and temperature are graphed and discussed in this paper. Growing heat source, energy inside the fluid boosts, thereby increasing the energy of the flow. Increase in generation of energy reduces the viscosity of the flow reduces thereby increasing the velocity of the flow particles. [ABSTRACT FROM AUTHOR]

In this paper, the influence of velocity slip and the Newtonian heating parameters on Williamson Nanofluid across a variable stretching sheet is studied. The basic fluid flow equations are turned into a system of coupled ordinary differential equations with appropriate conditions, which are solved numerically with the Keller-box approach. The outcomes show that, increasing Williamson parameter, due to the viscosity velocity of the fluid slowdown. As a result, it is noticed that the velocity slip parameter reduces Williamson Nanofluid velocity, while increasing shear stress, according to the results. Furthermore, it has been discovered that unlike velocity profiles, the slip influence is more pronounced on temperature and concentration profiles. Furthermore, the Newtonian heating parameter may be shown to have rising functions for velocity and dimensionless temperature. Newtonian heating has uses in the petroleum industry, heat exchangers, conjugate heat transfer around fins and solar radiation. It is discovered that the Joule heating parameter improves the thermal boundary layer thickness and slows down the velocity of the fluid, which aids in maintaining system temperature. Additionally, it has been found that the temperature profile exhibits a stronger slip effect compared with the velocity profile. To prepare toffee, chocolate and other delicacies as efficiently as possible, it is crucial to investigate the flow of Williamson fluids (such as drilling muds, clay coatings, various suspensions and some lubricating oils, thermoplastic melts, and a variety of colloids) in the incidence of heat transfer. The novelty of this paper is the effect of joule heating, Newtonian heating parameter and velocity slip on Williamson fluid velocity and temperature gradient. Furthermore, the heat and mass transfer rates are calculated for various parameters numerically and shown in tabular form. [ABSTRACT FROM AUTHOR]

The bioconvective flows are truly connected to real-life and engineering development. So, the models of biomicrosystems and biocells are considered for the technical analysis in this paper. Our intention for the current analysis was to theoretically examine electrical conduction flow into mass and heat transfer by an extensive gyrotactic microorganism into an inclined magnetic field toward a vertical stretching sheet with nonlinear solar radiation with different solar thermal appliances. The effect on velocity slip and Joule heating was again studied in detail. This classical problem on Navier Stokes equations to the current imitation was decreased to ordinary differential equations by applying the comparison method. The numerical solutions were changed by boundary value problem (BVP) to clarify the subject into finite difference numerical scheme by applying MATLAB. The important results show that the density of motile microorganisms reduces to the bioconvection Lewis number and Peclet number, although reverse performance was noticed for the bioconvection Rayleigh number. Further, solar radiation fosters heat transport. In this paper, complete analysis is provided for potential functions of solar thermoelectric cells, solar ponds, solar thermal power fabrication, etc. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the influence of past citations ki on papers' attachment rate Π(k, t) and propose a method to consider these influences by assigning different weights to ki. The correlation r between Π(k, t) and ki decrease rapidly with time, which suggests the different influences of past citations on the preferential attachment in citation networks. According to the different influences of ki on Π(k, t), we put different weights to ki and find a good linear dependence between Π(k, t) and the weighted past citations in three actual citation networks. [ABSTRACT FROM AUTHOR]

In this paper, the flow of an incompressible fluid is thermally studied. Investigations into the heat transfer process have been conducted in non-Newtonian fluid flows with chemical reactions and heat sources present. The application of this work is the fluid flow around the stretching sheet; fluid flow on a stretching sheet can be applied to polymer extrusion, drawing or plastic films, hot rolling, casting and other engineering problems. The novelty of this paper is that the governing equations have been solved by a new and efficient semi-analytical approach, the Akbari–Ganji method (AGM). In order to investigate the issue, the finite element method (FEM) has also been applied. Comparing the results of problem-solving with the applied methods with the results of the previous research shows a perfect agreement. The results show that the parameters of Hartmann number and interaction improve the velocity profiles. Additionally, for greater Hartmann number values, raising the parameter of interaction decreases the temperature value, but a smaller value has the reverse effect. As the Hartmann number increases, the fluid velocity decreases and it shows that with the increase of electromagnetic force, the velocity of fluid flow decreases. [ABSTRACT FROM AUTHOR]

The primary focus of this paper is the determination of novel soliton solutions for the (2 + 1) -dimensional Heisenberg ferromagnetic spin chain (HFSC) problem. The suggested model may be thought of as a special case of the nonlinear Schrödinger equation. Exact solutions to the proposed equation have been found using efficient analytical approaches such as the singular manifold method and the tan (η 2) -expansion method. These proposed methods are significant mathematical tools to obtain the exact traveling wave solutions of nonlinear complex partial differential equations (PDEs). After decomposing the governing problem into its real and imaginary components, we analyze both the real and imaginary components separately. Soliton solutions are obtained using computational tools like Maple. Trigonometric function solutions, rational solutions and hyperbolic function solutions are found for Heisenberg ferromagnetic model by the application of the proposed techniques. Furthermore, the physical properties of the solutions, such as hyperbolic functions, are important. The hyperbolic tangent is used in the computation of magnetic moment and velocity in special relativity. As a result, we hypothesize that the obtained results have physically comparable meanings to those stated by these collocations. By selecting suitable values of arbitrary parameters, it has been observed graphically that the amplitude of obtained solutions can be changed. Graphical representations of few of the reported solutions are presented in both two and three dimensions by choosing appropriate values of parameters. The suggested approaches are very efficient and reliable for finding exact solutions of wide range of nonlinear PDEs in a complex medium. The advantage of these techniques is evident since they are not limited in their ability to locate such wave patterns. Back substitution in the original equation using Maple 18 validated all solutions found, and the physical significance of these results has been underlined. The constraint conditions for the existence of constructed solutions are also provided in this paper. [ABSTRACT FROM AUTHOR]

Half-Heusler (HH) phases are among the most extensively studied thermoelectric materials. Bipolar thermal conductivity analysis performed for their sub-group based on rare-earth (R) metals, RNiSb, indicated high mobility ratio in favor of electrons. The result motivated studies of ScNiSb 1 − x Tex series in which n-type-doped samples shown higher mobility and significantly improved thermoelectric performance [K. Ciesielski et al., Phys. Rev. Appl.  15, 044047 (2021)]. Recently, Kajikawa attempted alternative interpretation of transport properties in ScNiSb, where multi-parameter fit led to mobility ratio in favor of holes [Y. Kajikawa, Int. J. Mod. Phys. B 2250071 (2022)]. In this work we discuss the details of electrical properties and thermoelectric performance of ScNiSb in the context of structural disorder and the most recent experimental literature on a related chemical system. The paper considers also relevant assumptions regarding band degeneracy and scattering mechanisms for effective mass modeling in ScNiSb. Last, technical difficulties of the model proposed by Kajikawa are addressed. We believe that the provided insight will be useful for understating electrical transport in HH compounds, which can contribute to further improvement of their thermoelectric performance. [ABSTRACT FROM AUTHOR]

This paper studies the mixed convective flow of a magnetohydrodynamic micropolar fluid over an extending sheet. The first-order velocity slip condition is taken to observe the slip flow of the fluid. The applications of solar radiation toward the micropolar fluid flow are analyzed in this paper. Furthermore, the Brownian motion, thermophoresis and Joule heating impacts are also studied. Also, the Cattaneo-Christov heat flux model, chemical reaction and activation energy are observed. The leading PDEs have been transformed to ODEs and then solved with the help of homotopy analysis technique. The impacts of different physical parameters have been evaluated theoretically. The outcomes exhibited that the material factors have augmented the microrotation and velocity profiles. Moreover, the velocity slip parameter has a reverse relation with velocity and microrotation profiles, while there is a direct relation of a velocity slip with the energy curve. The velocity profile has increased with higher thermal and mass Grashof numbers. With increasing Brownian motion parameter, the thermal profile is amplified while the concentration profile is declined. On the other hand, the thermal and mass profiles have been boosted with greater thermophoresis parameter. The velocity profile has decreased with higher magnetic parameter, whereas the temperature profile has augmented with higher magnetic parameter. The couple stress and skin friction have been augmented with material parameter, whereas the skin friction has been reduced with thermal and mass Grashof numbers. [ABSTRACT FROM AUTHOR]

This paper focuses on a new superposition between a single lump wave, breather waves and line solitons of the (2 + 1) -dimensional generalized Korteweg–de Vries (gKdV) equation. After deriving the N-soliton solutions, a new constraint, the long-wave limit and mode resonance method are used to construct a new hybrid solution. Further, a new velocity resonance condition is proposed to obtain a velocity resonance solution consisting of a single lump wave, a line soliton and breather waves, which remains relatively stationary and form a new bound state. It is worth pointing out that in most of the previous literature, lump wave and other waves will separate after they collide, but this paper derives a different result. [ABSTRACT FROM AUTHOR]

Researchers always like to find way for improving the performance of system integrated with PCM. In this paper, the container was combined with fins and PCM was mixed with nanoparticles to obtain quicker discharging process. Two significant variables related to second technique are fraction of additives (ϕ) and their shapes (m). To involve these factors in equations, single phase formulation was applied. Low magnitude of velocity of liquid material in freezing leads to simplification of equations of this transient procedure. Galerkin method which was applied for this modeling has good accommodation with previous publication. As ϕ soars, the solidification time declines from 4802.97s to 4244.61s and 3738.37s when blade shape particles were applied. This means that adding additive can enhance the rate of process about 22.16%. Moreover, augmenting the shape factor to higher level causes time to drop about 5.7%. [ABSTRACT FROM AUTHOR]

In this paper, new exact traveling wave solutions are obtained by Hirota–Ramani equation. The many exact complex solutions of several types of nonlinear partial differential equations (NPDEs) are presented using the modified extended direct algebraic approach and new extended direct algebraic method, which is among the most effective mathematical techniques for finding a precise solution to NPDEs and put into a framework of algebraic computation. By selecting different bright and solitary soliton forms and by creating various analytical optical soliton solutions for the investigated equation, we hope to demonstrate how the analyzed model's parameter impacts soliton behavior. It is possible to obtain new, complex solutions for nonlinear equations like the (1 + 1) -dimensional Hirota–Ramani equation. [ABSTRACT FROM AUTHOR]

This paper investigates the Magnetohydrodynamics (MHD) convective flow over a cone with the influence of viscous dissipation, variable viscosity, chemical reaction and variable thermal conductivity effects. Related equations are tackled by the Homotopy analysis method (HAM). The impacts of physical variables on concentration, velocity and temperature are presented through numerical tables and graphs. It is noticed that the heat transfer rate (Nusselt number) increases against Prandtl number. Similarly, the mass transfer rate (Sherwood number) increases against Schmidt number. Also, it is seen that skin friction in tangential and azimuthal direction increases against the buoyancy forces ratio parameter. Current results are validated with previous literature work. [ABSTRACT FROM AUTHOR]

In this paper, we report the optoelectronic, thermoelectric properties and dynamic stability under the pressure of LiGaC half-Heusler within the Density Functional Theory (DFT) and semi-classical Boltzmann Transport Theory (BTT). The obtained results of the ground state show that the compound is structural, chemical, mechanical and dynamically stable in type I structure and maintains its stability under pressure. The obtained electronic properties reveal that the compound has a semiconducting nature with an indirect bandgap and the bandgap values slightly increase with pressure increase. The optical properties such as real and imaginary parts of dielectric function, refractive index and extinction coefficient, reflectivity and absorption coefficient and optical conductivity are calculated and discussed. The highest peaks of reflectivity and absorption coefficient are found in the ultra-violet (UV) region, suggesting that the compound LiGaC has a high potential for use in UV optoelectronic applications. The thermoelectric properties are also calculated in the temperature range from 300 K to 900 K and pressure range from 0 GPa to 40 GPa. At 300 K and for all pressures selected, the maximum value of figure of merit is close to unity. Finally, we could make our conclusion that LiGaC is well suitable for multiple optical and thermoelectric applications. [ABSTRACT FROM AUTHOR]

In the existing investigation, impacts of slip and chemical reactions on mass and heat exchange on an incompressible and electrically conducting micropolar fluid past a porous wedge within the sight of Hall and ion slip are examined. By employing similarity conversion, the relevant highly nonlinear PDEs are reformed into a collection of nonlinear linked ODEs. The equations framed in this manner have been resolved by using the bvp5c, the in-build MATLAB. Examination of magneto-hydrodynamic micropolar fluid on stagnation point flow is significant due to its uses in the production of plastic substances, polymer extrusion, lubricants, etc. The influence of the magnetic field, heat generation, microrotation, along with Hall and ion slip on the liquid flow is analyzed. Examination with prior published research papers is performed and the outcomes are compared with each other. Numerical simulations for shear stress coefficients, Sherwood and Nusselt numbers are provided in tabular form, and in addition, the variations in axial and microrotation velocities, temperature and solutal profiles are evaluated visually for various parameters in detail. The ion slip and slip velocity both slow down the shear rate, whereas the elevated values of the Hall and magnetic parameters show an opposite trend. The profile shows thinning of the bounding surface and offers its greatest magnitude in the case of a Newtonian liquid. [ABSTRACT FROM AUTHOR]

In solid-state systems, spin squeezing states have acquired much interest in quantum information processing since they are not only essential from a basic physics standpoint but also have many applications, notably reducing noise in interferometry. This paper addresses the study of quantum nonlocality as examined by the violation of the Bell and Clauser–Horne–Shimony–Holt (CHSH) inequality in two classes of spin squeezing states and how this relates to the quantum-memory-assisted entropic uncertainty relation (QMA–EUR). The spin squeezing states in the two classes are systematically generated by two twisting nonlinear interactions. These separately describe two spin- 1 2 interaction mechanisms that undergo one-axis twisting (OAT) and two-axis countertwisting (TAC). We investigate each spin squeezing mechanism in a thermal bath ( k B T) with a transverse magnetic field. Our main results indicate that the degree of violation of the Bell-CHSH inequality and the entropic uncertainty relation (EUR) is typically anticorrelated in both mechanisms. We demonstrate that the spin squeezing states in the OAT mechanism violate the Bell-CHSH inequality and thus exhibit Bell nonlocality only at low temperatures ( k B T → 0), whereas in the TAC mechanism, increasing the strength of the spin squeezing interaction leads to a violation of the Bell-CHSH inequality even at finite temperatures. We have also shown that there is always an expansion of the EUR and a decrease in the degree of violation of the Bell-CHSH inequality in the high-temperature regime. In addition, the transverse magnetic field exhibits different behavior under the considered temperature regimes in the two classes of spin squeezing states. Other results will also be discussed. [ABSTRACT FROM AUTHOR]

Nanotwin strengthening mechanism has been successfully applied to a variety of metallic materials. The strengthening originates from the hindering effect of twin-boundary (TB) on dislocations, and the formation of twin is greatly determined by the magnitude of the TB energy (TBE). In this work, the TBEs of three face-centered-cubic (FCC) metals were calculated by first-principles, the effect of the supercell size (the TB spacing and TB area) on the TBE was investigated, and the relationship between the TBE and the twinning formation mechanism was discussed. The results show that the TBEs calculated in this paper are in good agreement with the experimental values. Meanwhile, the magnitude of the TBE explains reasonably the twinning formation ability of these FCC metals in experiments. [ABSTRACT FROM AUTHOR]

The squeezing and statistical features of the intracavity field produced by a three-level laser coupled to a vacuum reservoir with input coherent field are studied in this paper. Employing the propagator method, we determine the Q-function for the cavity field produced by a driven three-level laser. Using this Q-function, we have calculated the mean intensity, the quadrature variance, and the squeezing spectrum of the cavity field. It has been discovered that, despite the fact that the input coherent field improves the mean intensity of the cavity field, it has no effect on the quadrature squeezing of the cavity field. The degree of squeezing increases with the rate at which atoms are injected into a cavity and a substantial degree of squeezing is found close to the maximum initial injected atomic coherence. [ABSTRACT FROM AUTHOR]

The pull-down instability is a newly found phenomenon for oscillators with even nonlinearities. It is a seemingly periodic motion, which will suddenly pull down after some cycles. The phenomenon is similar to the pull-in instability in the micro-electromechanical systems. This paper restudies the well-known Toda oscillator, which is considered to be in periodic motion. Its pseudo-periodic property is studied and the pull-down instability is found for the first time ever. To this end, this paper establishes a variational principle for the Toda oscillator, and the criterion for prediction of the pull-down motion is obtained. A simple formulation to calculate the pull-down instability is proved and verified through examples. Furthermore, an approximate frequency formula is obtained by Li–He modified homotopy perturbation method. [ABSTRACT FROM AUTHOR]

In this study, we use molecular dynamics (MD) simulation to predict the thermodynamics, structural, and transport characteristics of liquid para-hydrogen (para-H 2) over a wide temperature range. The Feynman–Hibbs (FH) technique employs Lennard-Jones pair potentials (LJ) which are enhanced by quantum modifications to describe molecular interactions. Results retain the FH's structural, thermodynamics and transport properties, and the classical LJ models (the radial distribution function, total energy, pressure, potential energy, enthalpy, diffusion coefficient, and shear viscosity). The datasets included in the paper were also considered, along with the experimental data collected, where possible. This work shows that for liquid para-H2, FH approach integrated to classical MD simulation, including quantum corrections yields an excellent accordance with the experimental findings. The FH potential improves concordance with the shear viscosity and diffusion coefficient values, as demonstrated by the results. With greater accuracy to experimental data, the FH Molecular Dynamics approach (FHMD) predicts such values. [ABSTRACT FROM AUTHOR]

As a new quantum state, topological insulators have become the focus of condensed matter and material science. The open system research of topological insulators has aroused the interest of many researchers. In this paper, we study the response of topological insulators to a single-mode quantized field with momentum. We solve the ground state of the system after the addition of a single-mode light field with adjustable photon momentum. To be specific, the analytical solution of Hall conductance has an additional correction compared with the closed system, and the Hall conductance can no longer be expressed by the weighted sum of the Chern numbers. Furthermore, the topological properties are analyzed and discussed through the results of an instance with their illustration. The system still has a topological phase transition and the critical point of the topological phase is robust to the single-mode quantized field. [ABSTRACT FROM AUTHOR]

In the absence and presence of a circularly polarized monochromatic electromagnetic pulse, we have analyzed the electron–nucleon scattering process, where the nucleon is assumed to be spinless with a spherical shape. We have provided the theoretical calculation of the differential cross section (DCS) by using the Dirac–Volkov formalism. This research paper aims to provide two comparisons: We first compare the DCS in the absence of the laser field with its corresponding laser-assisted DCS. A second comparison is made between the electron–proton and electron–neutron scattering processes to study the effect of the laser on both processes. The results obtained about the effect of the laser field on the DCS and the electric form factor have been discussed for both scattering processes. We have found that the DCS is reduced when the laser field is applied for both processes. In addition, the form factor is also decreased by raising the incident electron energy in electron–proton scattering, but it increases in electron–neutron scattering. Moreover, the form factors for both scattering situations are unchanged by raising the laser field strength up to 1 0 8 V/cm. [ABSTRACT FROM AUTHOR]

Roll coating is a popular method for applying a thin coating film to a continuous substrate, such as paper or foil. This study aims to investigate analytically the fluid flow through counter rotating rolls using a non-Newtonian model. The governing equation for the constitutive of the Oldroyd-B as a non-Newtonian fluid with momentum equation has been discovered. The nondimensionalizing of the fluid flow equations is done by using suitable dimensionless parameters. The equations are then simplified by using Lubrication Approximation Theory (LAT) to obtain the solution for various quantities. Analytical solutions for the velocity distribution, pressure and pressure gradients have been obtained by regular perturbation method. Numerical integration has been used to calculate separation point, coating thickness, separation force and power input of the fluid. The effect of involved parameter such as Weissenberg number We and viscosity on velocities, pressure gradient and pressure is presented in a variety of graphs and several other results are shown in tables. It has been observed that as the modified capillary number N C a 2 increases, the separation point moves toward the nip region, whereas the coating thickness declines. It has been witnessed that the We serves as the controlling parameter for flow rate, pressure distribution and power input, whereas for the coating thickness, the separation force increases, which are important for coating industries. [ABSTRACT FROM AUTHOR]

In this paper, the effect of C, N and O atom doping of intrinsic MoSe2 on the adsorption capacity of Ni is investigated based on first-principle research methods. The aim is to analyze whether intrinsic MoSe2 can be doped and modified to improve its adsorption capacity of Ni so that it can be used as a new type of adsorbent material. By calculating and analyzing the energy band structure, density of states, differential charge and optical properties of each system, the conclusions are as follows: the O-doped MoSe2 system has the best adsorption capacity for Ni, and the adsorption capacities of the three systems are in the following order: O>N>C. The bandgap value of intrinsic MoSe2 adsorbed Ni-atom decreases, while the Fermi energy level of the C-doped MoSe2 adsorbed Ni-atom system is located in the valence band, which shows p-type doping. The differential charge of the system was analyzed and the charge transfer of the adsorbed system was increased by C, N and O atom doping, and the O-doped system had the strongest adsorption capacity for Ni. It was shown that the charge distribution between the system and the adsorbed Ni-atom changed considerably after atomic doping, and the bonds between the Ni-atom and the dopant atoms of the C-, N- and O-doped adsorption system were strongly ionic. Optical analysis reveals that C, N and O atom doping improves the charge binding ability of Ni-adsorbed MoSe2 material, which gives it a higher polarization rate and faster electric field response. The absorption of ultraviolet light is greatly enhanced, which can improve the efficiency of solar cells and convert solar energy into electricity more effectively. Overall, the Ni adsorption capacity of atomically doped MoSe2 is improved, indicating that doping can be an effective means to improve the adsorption of Ni-atom by intrinsic MoSe2. It is hoped that the research results in this paper can provide some theoretical guidance for the application of MoSe2 in optoelectronic devices. [ABSTRACT FROM AUTHOR]

This paper examines the use of Phase Change Materials (PCM) in Building-Integrated Photovoltaic (BIPV) systems. To assess the performance of BIPV–PCM systems, the study employs a Strengths, Weaknesses, Opportunities and Threats (SWOT) analysis. The study features the advantages of using PCMs with BIPV envelopes. The benefits include lower heating and cooling requirements, shifted peak loads and increased thermal comfort. However, there are several challenges like heat loss and lower energy efficiency which needs to be addressed. Further, the potential for reduced PCM efficiency over time is recognized. The paper concludes by recommending further research on alternative PCM placement strategies, enhanced PCM formulations, gypsum board integration and the evaluation of PCMs combined with nanoparticles. [ABSTRACT FROM AUTHOR]

This paper provides a comparative numerical analysis of unsteady hybrid nanofluid (Ag + TiO 2 /H2O) and nanofluid (TiO2/H2O) flows through a permeable linear stretching cylinder placed in a porous medium has been presented in the presence of oblique Lorentz force. The flow regulating boundary layer equations has been governed due to the sway of the suction, viscous-Ohmic dissipation, heat source, thermal radiation and first-order velocity slip with imposing convective boundary conditions on the surface. The self-similar transformation has been employed to convert the governing coupled nonlinear PDEs into a set of ODEs and finally solved them numerically by fifth-order Runge–Kutta method with shooting technique. Finally, a comparative study has been made on the thickness of the momentum and thermal boundary layers due to the effect of governing parameters for simple and hybrid nanofluids. Further, a numerical observation on local skin friction and thermal-transport coefficients is presented with the help of tables. The result indicates that the progressiveness of the velocity profile reduces for the unsteadiness parameter, Hartree pressure gradient, velocity slip parameter, inclination parameter, porous medium parameter, magnetic parameter and suction parameter while improving for velocity ratio parameter and temperature profiles increases with Biot number, Eckert number, heat generation parameter and thermal radiation parameter, but decreases for Hartree pressure gradient and velocity ratio parameter. This work has found various applications in high-temperature and cooling processes, paints, conductive coatings, medicines, space technology, biosensors, conductive coatings and so on. [ABSTRACT FROM AUTHOR]

In this paper, an attempt has been made to investigate a one-dimensional photonic crystal containing N-doped germanium semiconductor as a nonlinear defect layer with an intensity-dependent refractive index, silica (SiO2) and zinc selenide (ZnSe) as crystal cells. Bistability of the TE polarization of the transmission spectrum due to the nonlinear property of the defect layer is investigated by the transfer matrix method (TMM). The refractive index of the germanium nonlinear semiconductor layer is simultaneously depending on the doping density and the intensity of the irradiated light. The changes in both factors are investigated. The impact on the transmission spectrum of the bistability threshold due to the change in the thickness of the defect layer, the thickness of other layers of crystal cells, and the angle of incident light are investigated. The nonlinear effect caused by light intensity as well as doped density effect on the germanium nonlinear semiconductor medium is used simultaneously. As a result, the nonlinear effect caused by the light intensity to create bistability is more than the doping density. [ABSTRACT FROM AUTHOR]

The regulation of energy associated with heat transfer is the most important problem in the food processing, chemical and biomedical engineering industries. Therefore, this investigation explores the heat transfer qualities of micropolar hybrid-nanofluid also considering entropy generation which has recently become central focus of research in the field of heat transfer processes. The purpose of this analysis is to explore the influence of magnetohydrodynamics (MHD), viscous dissipation, and heat radiation on the flow of hybrid-nanofluid with micropolar properties above an exponentially shrinking/stretching sheet. A mathematical model is constructed and the solution is acquired by utilizing numerical technique bvp-4c in MATLAB. The befitting usage of the second law of thermal physics helped in conducting the entropy production analysis. The study obtains numerical results for the governing equations, which reveal dual solutions when analyzing a shrinking sheet, contrary to a stretching sheet. The paper presents graphical depictions of the influence of different attributes upon micro-rotation, velocity, surface-friction, temperature, Nusselt number and also the entropy generation plus the Bejan number. Moreover, a comparison of heat transfer rates between conventional nanomaterial and hybrid-nanofluid is provided. The study concludes that dual solutions appear and the wall shear stress coefficient decreases as the values of micropolar parameter R 1 increase with critical values of λ being λ c = − 1. 2 8 , − 1. 3 4 and − 1. 3 7. Also thermal irreversibility, which results from fluid friction near the sheet rather than far from it, is more dominant than total entropy generation. [ABSTRACT FROM AUTHOR]

In this paper, we examine the shape effects of different nanoparticles of an incompressible, unsteady flow of a nanofluid Al 2 O 3 with water H 2 O as the base fluid over a rotating disk. Magnetic field results are also added. In this research, four distinct shapes of Al 2 O 3 nanoparticles, i.e., sphere, blade, cylinder and brick, have been employed. Every shape is suspended at the same volume. After using the Von Karman transformation, the Navier–Stokes equation, along with the magnetic field effect and the thermal energy equation, is numerically solved by using the bvp4c MATLAB solver. The effects of various parameters on the velocity field and temperature profile are illustrated graphically. This analysis is validated by comparing it to the previously described research. Furthermore, increasing the volume fraction parameter 0 ≤ ϕ ≤ 0. 1 % causes the radial, tangential, and axial velocities near the disk for the shapes brick, cylinder, and blade to decrease and increase for the shape sphere. The fluid rotating in front of the disk rotates more slowly for small values of the unsteadiness parameter α ̂. The magnetic field M has a significant influence on the axial flow when the suction parameter values are small, but this impact is limited when the suction parameter values are large. [ABSTRACT FROM AUTHOR]

Experimental studies have shown that many natural and artificial systems need to maintain stable oscillations during application, but the occurrence of oscillation quenching phenomenon will destroy the oscillation activity of the system and hinder the normal operation of the system. In this paper, to solve the important problem of oscillation quenching leading to system paralysis, the weighted average function of oscillators is applied to each oscillator as an external feedback, which is an extension of the mean-field feedback [N. Zhao and Z. Sun, Int. J. Bifurcation Chaos 30, 2050094 (2020)]. Taking the Stuart–Landau oscillators with the identical and nonidentical frequencies as examples, respectively, we find that the weighted average feedback is better than the previously proposed mean-field feedback in eliminating oscillation quenching with different coupling scenarios. Especially, when the weight is 0 or 1, that is, when a single oscillator is used as the feedback, the weighted average feedback is highly efficient in reviving oscillation. Our results provide a more convenient method to overcome these quenching states of coupled systems, and broaden the practical applications with respect to revoking rhythmic oscillations via external feedback in nature and real life. [ABSTRACT FROM AUTHOR]

In this paper, the thermal behavior of cylindrical and conical pin fin structures operating in a convective–radiative environment has been examined. The fully wet porous fin structures are assumed to be mounted with a stretching/shrinking mechanism similar to a conveyer belt. The conical pin fin has been comparatively analyzed with the cylindrical one for three distinct cases of stretching, stagnant, and shrinking. Further, the Darcy model has been employed to analyze the fluid–solid interactions. The differential transformation method (DTM) has been used to solve the resulting second-order nonlinear ordinary differential equations. On the thermal performance of conical and cylindrical pin fin structures, the effects of the stretching/shrinking parameter, Peclet number, wet porous parameter, convective parameter, and radiative parameter have been established graphically. The conical pin fin is found to aid the heat transmission process better than the cylindrical one. The work is also helpful in the realm of microelectronics, particularly in the development of micro-pin-fin structures. [ABSTRACT FROM AUTHOR]

In this paper, we explore the use of opinion dynamics models to examine changes in opinions of lifelong learning, and to identify groups of people for targeted intervention to improve their reception to lifelong learning. This method has a multitude of potential applications related to clustering and segmentation. Singapore's initiative for lifelong learning, SkillsFuture, serves as a case study for the application of the technique. We first found a positive correlation between how motivated people are to learn and a negative correlation between how much people know about SkillsFuture opportunities, with respect to their reception to SkillsFuture courses. Then, we used an opinion dynamics model to model the evolution of opinions to produce clusters of people whose opinions will converge. The clusters were then grouped into three groups: those with the largest increase, largest decrease and a middle group. Further examining the covariates of the people in each cluster (e.g., age, last drawn salary, etc.), we propose organizing sharing sessions for the group with the largest increase, intervention for the group with the largest decrease, and gathering more information about the motivations of the middle group. [ABSTRACT FROM AUTHOR]

This work has studied some nonlinear optical properties of Al0.3Ga0.7As/GaAs quantum dot system with tangent-square potential (TSP), with special emphasis on the role of second harmonic generation (SHG) coefficient under hydrostatic pressure and temperature. Due to the strain of external application conditions, the changes of the energy level and wave function of the neutron band in the system structure provide valuable insights into the optical properties of the quantum dot structure. In this paper, we report the effects of structural parameters, temperature and hydrostatic pressure on the SHG coefficient. According to the results obtained in the work, it can be reported that the nonlinear optical properties of the quantum dot system can be improved by adjusting the hydrostatic pressure and temperature. At the same time, the interaction of various parameters has produced some interesting observations, which are relevant in relevant research fields. [ABSTRACT FROM AUTHOR]

In this paper, the spin wave theory is applied to the Heisenberg spin bilayer with intralayer ferromagnetic interaction J 1 , intralayer single-ion anisotropy D and interlayer antiferromagnetic interaction J 2 . It is found that the effects of both D and J 2 on the thermodynamic quantities give rise to the two different low-temperature asymptotic behaviors with and without exponential law. For D > 0 , the interlayer antiferromagnetic interaction can induce the appearance of the maximum of the layer magnetization at finite temperatures. At the location of the layer magnetization maximum, the approximate behaviors (such as the power, linear, rational, exponential and logarithmic laws) which are driven by the temperature or the anisotropy, are obtained for the low-temperature thermodynamic properties. It is shown that the presence of antiferromagnetic interlayer interaction J 2 clearly induces more quantum fluctuations than the case where the interlayer interaction J 2 is ferromagnetic. Our results of the layer magnetization agree with the experimental data of the layered van der Waals crystal FeCl2 at low temperatures. In the monolayer case of J 2 = 0 , our results are in agreement with the findings obtained by the existing theories and the quantum Monte Carlo data. [ABSTRACT FROM AUTHOR]

In this research paper, the authors wish to examine the effects of couple stress on hybrid nanofluid considering magnetohydrodynamic three-dimensional transient flow between two parallel plates. Stretching of the lower plate causes fluid flow in the channel. The fluid flow model is shown in mathematical form using a set of coupled nonlinear partial differential equations, which are then translated into coupled nonlinear ordinary differential equations using the proper transformation. The authors used the spectral quasi linearization method (SQLM), an effective numerical technique, to solve the updated equations and study the effects of various flow parameters on fluid temperature and velocity. The Nusselt number and skin friction coefficients were also investigated from an engineering standpoint. The generated solutions are verified using the residual analysis. Statistical analysis is performed on the skin-friction coefficients and the Nusselt number using quadratic regression models. [ABSTRACT FROM AUTHOR]

This paper signifies the consequence of the thermal diffusion (Soret) and diffusion-Thermo (Dufour) effect on MHD stagnation point flow and transportation of thermal energy near a stretching plate. However, the inclusion of thermal radiation, heat generation/absorption, and chemical reaction enriches the profiles significantly. By using similarity transformation, the set of leading equations is altered into a set of dimensionless ordinary differential equations. After that, the aim is to convert boundary layer equations into dimensionless ones so that the set of converting equations is computed by using bvp4c solver on MATLAB software. The governing nonlinear equations were resolved with Runge–Kutta fourth-order technique numerically. The significance of radiation, magnetic field, suction, Schmidt number, velocity ratio parameter, heat absorption coefficient, permeability, thermo-diffusion number, diffusion-thermo number on momentum gradient, energy gradient and concentration gradient distribution is analyzed. The parameters, diffusion-thermo number Du and thermo-diffusion number Sr have opposite behaviors on both temperature and concentration fields. Here, also, it is observed that the heat sink parameter has a noticeable influence on the fluid temperature distribution profile. [ABSTRACT FROM AUTHOR]