Modern Physics Letters B最新文献

This paper delves into the intricacies of the ($2+1$)-dimensional asymmetric Nizhnik–Novikov–Veselov ($𝔸\mathbb{N}\mathbb{N}𝕍$) model, a nonlinear partial differential equation governing ion-acoustic wave propagation in plasma. By employing advanced analytical and numerical approaches, the study explores innovative solitary wave solutions, particularly focusing on the dynamics of isochoric flow. Isochoric flow analysis is crucial for unraveling the complex behaviors exhibited by incompressible fluids like elastomers and bio-elastomers, which maintain a constant density.

The derivation of the ($2+1$)-dimensional $𝔸\mathbb{N}\mathbb{N}𝕍$ equation stems from fluid equations governing plasma dynamics. This model serves as a valuable tool for simulating experimental observations of plasma waves. The computational methodology applied in this research demonstrates a commendable level of precision and consistency, yielding novel solitary wave solutions previously unreported in the $𝔸\mathbb{N}\mathbb{N}𝕍$ model. These results underscore the study’s importance and novelty.

The outcomes not only contribute to our understanding of incompressible fluid dynamics, but also lay the groundwork for future investigations in this domain. The revealed solitary wave solutions have the potential to inform the development of more accurate models for predicting fluid dynamics, thereby advancing the field.

The miniaturization of electronic devices without compromising their heat dissipation capacities is the main concern due to the rapid evolution in power industries and engineering fields. The conventional methods of cooling or heating the devices are changed and old tactics of using conventional fluids for heat dissipation are replaced with nanofluids of strong thermal efficiency. In the present context, the experimental as well as theoretical studies of nanofluids (Cu–H₂O/Al₂O₃–H₂O) flow inside the wavy and microchannels are elucidated and discussed for different physical conditions. It is found that the use of Cu–H₂O/Al₂O₃–H₂O nanofluid improves the thermal efficiency of heat exchangers. The complex shapes and sizes of heat exchangers such as multilayer heat exchangers, heat exchangers with twisted and square shapes and multijet heat exchangers are considered effective coolants as compared with straight microchannel heat exchangers. The use of Cu–H₂O/Al₂O₃–H₂O nanofluids improves the overall heat transfer efficacy of electronic devices, and it is considered a promising coolant for various applications including aerospace (spacecraft and satellites), automobile (cooling the engines and power management in electric vehicles), renewable energy (solar plants), microelectronic devices (heat dissipation through the microprocessor and cooling the other components of devices) and modern heat exchangers of engineering domains.

This work explores the investigation of tin monochalcogenides i.e. SnX (X: S, Se, Te) at room temperature (300$$K). The mechanical, thermophysical and ultrasonic properties of SnX (X: S, Se, Te) have been evaluated using the computed values of second- and third-order elastic constants (SOECs and TOECs). The SOECs and TOECs have been obtained using Born–Mayer potential model at 0$$K and 300$$K. The brittleness behavior of tin monochalcogenides is detected by Pugh’s ratio. It is observed that phonon–phonon interaction mechanism is dominant in tin monochalcogenides leading to high ultrasonic attenuation. The obtained temperature dependence behavior of tin monochalcogenides is validated via comparison with available works of literature data in previous works done experimentally as well as theoretically by others.

This research explores different types of exact wave solitons of nonlinear (4+1)-dimensional Davey–Stewartson–Kadomtsev–Petviashvili (DSKP) model along truncated M-fractional by applying the Sardar sub-equation and generalized Kudryashov methods. This model describes the interactions among internal waves. This model is used to represent the nonlinear natural occurrence. The obtained results involve dark, singular, bright, periodic and other solitons. The gained results satisfy the concerned model and are represented by 2D, 3D and contour graphs. The gained results are not present in the literature due to the use of fractional derivative. Impacts of truncated M-fractional derivative on gained results are also represented by graphs. Hence, our gained results are fruitful in the future study for these models. Finally, we conclude that the applied techniques are simple, fruitful and reliable to solve the other models in mathematical physics.

Quantum Secure Direct Communication (QSDC) is a promising approach for secure information exchange. This paper proposes an efficient and secure four-party QSDC scheme utilizing hyperentangled Bell states in the polarization degree of freedom, the first longitudinal momentum degree of freedom and the second longitudinal momentum degree of freedom. The four participants can perform different unitary operations to independently encode their secret messages onto photons in three degrees of freedom, subsequently transmitting them directly through the quantum channel. In this proposed protocol, each degree of freedom of the photon can effectively carry two bits of information. Each round of transmission by a photon enables the four legitimate participants to obtain six classical bits of information. Notably, when compared to other photons based single-degree-of-freedom QSDC network protocols, the capacity of proposed QSDC protocol is tripled. Therefore, it significantly enhances the information transmission capability. Furthermore, comprehensive security analysis shows that our QSDC network protocol can withstand various attacks from external eavesdroppers.

Design optimization of multilayer piezoelectric transducers is intended for efficient and practical usage of wideband transducers for fault diagnosis, biomedical, and underwater applications through adjusting layer thicknesses and volume fraction of piezoelectric material in each layer. In this context, we propose a parallel differential evolution (PDE) algorithm to mitigate the complexities of multivariate optimization as well as the computation time to achieve an optimized wideband transducer for the particular application. For lead magnesium niobate-lead titanate (PMN PT)- and PZT5h-based piezoelectric materials, the fitness function is formulated based on uniformity of mechanical pressure at the first three harmonics to achieve wide bandwidth in the required functional frequency range. It is carried out using a one-dimensional model (ODM), while input layer thicknesses and volume fractions of active material are evaluated using PDE. The simulation is performed on a parallel computing platform utilizing three different host machines to reduce computational time. Results of the proposed methodology for PDE are statistically represented in the form of minimum, maximum, mean, and standard deviation of fitness value, while graphically represented in terms of speedup and time. It can be observed that the execution time for parallel DE decreases with the increasing number of cores.

The emergence of order from initial disordered movement in self-propelled collective motion is an instance of nonequilibrium phase transition, which is known to be first order in the thermodynamic limit. Here, we introduce a multiplicative scalar noise model of collective motion as a modification of the original Vicsek model, which more closely mimics the particles’ behavior. We allow for more individual movement in sparsely populated neighborhoods, the mechanism of which is not incorporated in the original Vicsek model. This is especially important in the low velocity and density regime where the probability of a clear neighborhood is relatively high. The modification, thus, removes the shortcoming of the Vicsek model in predicting continuous phase transition in this regime. The onset of collective motion in the proposed model is numerically studied in detail, indicating a first-order phase transition in both high and low velocity/density regimes for systems with comparatively smaller size which is computationally desirable.

This analysis explains the magneto-hydrodynamic flow on Williamson nanofluids previous stretching surface surrounded by the permeable media. The apt magnetic field was suggested for the angle of the axial direction of the flow. Anyhow, this flow phenomenon was characterized into the added heat source/sink and conjunction of radiating heat. The impacts of convective heating and viscous heating by expanding surface were again the significant feature of the analysis. This originality arises by the combination of the cross-diffusion effects of reverse behavior on the thermophoresis and Brownian motion. This form sketched into the aforesaid phenomenon was modified into the nonlinear ordinary form by the appropriate assumptions on comparison transformations. Therefore, the sets of equations were controlled for the numerical access using Lobatto-IIIa collocation method applicable to this Matlab bvp4c shooting process. This parametric performance of many components about their statistical values was given numerical imitations graphically by the rate coefficients in tabular forms. The validation and the compliance of the current result were acquired by the past study on the specific case. Further, the significant results of this analysis were: This non-Newtonian Williamson parameter combination of that magnetizing property diminishes the fluid velocities. In addition, the important influence of both viscosity parameter and radiation parameter of heating process was noted.

This study explores solutions for a mathematical equation called the time-space fractional phi-four equation using two methods: the Sardar-subequation method and the modified extended auxiliary equation method. The phi-four equation is connected to the Klein–Gordon model and is important in different scientific areas like biology and nuclear physics. Understanding its solutions is crucial. By using a specific wave transformation, the equation is changed into a simpler form for analysis. The methods proposed give a variety of solutions, such as Kink, bright singular, dark, combo dark bright, periodic, and singular periodic solutions. Each solution we find using these methods has specific rules that determine when it’s correct. We carefully choose specific values for the parameters to help us understand more about the solutions. This helps us see the detailed features of the solutions and improves our understanding of how the model behaves in the real world. These methods create a strong framework for studying solitons, which are specific types of mathematical solutions. The study compares the outcomes of these methods with earlier ones to get a complete understanding. Graphical illustrations are used to visually represent some of these solutions, helping us grasp their characteristics. Visual representations in two- and three-dimensional figures add originality to the findings. Importantly, these methods can be applied to solve similar problems with fractional derivatives in various scientific contexts. In summary, this research not only deepens our understanding of the phi-four equation but also introduces powerful methods with broad applications in fractional differential equations.

Using the bilinear neural network method (BNNM) and the symbolic computation system Mathematica, this paper explains how to find an exact solution for the (2+1)-dimensional Korteweg–de Vries–Sawada–Kotera–Ramani (KdVSKR) equation. In terms of activation function and weight coefficient, BNNM is a more appealing option for users than traditional symbolic computation methods. It is possible to develop a wide range of solutions and expand the classes of exact solutions by modifying the activation function. The activation function’s versatility allows it to generate a wide range of solutions with several theoretical and practical uses. The analytical solution is obtained by using a double layer type, while the rogue wave solution and mixed solutions are obtained by using a single layer type. The evolution of these waves is then illustrated using various 3D graphs, 2D graphs, and density plots.