International Journal of Modern Physics B

Incompressible fluids are studied in such disciplines as ocean engineering, astrophysics and aerodynamics. Under investigation in this paper is a $(3+1)$-dimensional Boiti–Leon–Manna–Pempinelli (BLMP) equation in an incompressible fluid. Based on the known bilinear form, BLMP hybrid solutions comprising a lump wave, a periodic wave and two kink waves, and hybrid solutions comprising a breather wave and multi-kink waves are derived. We observe the interaction among a lump wave, a periodic wave and two kink waves. Fission of a kink wave is observed: A kink wave divides into a breather wave and three kink waves. On the contrary, we see the fusion among a breather wave and three kink waves: The breather wave and three kink waves merge into a kink wave. Finally, we observe the interaction among a breather wave and four kink waves.

Ultrasonic impact treatment (UIT) is an effective method that has been widely applied in welding structure to improve the fatigue properties of materials. It combines mechanical impact and ultrasonic vibration to produce plastic deformation on the weld joints surface, which introduces beneficial compressive residual stress distribution. To evaluate the effect of UIT technology on alleviating the residual stress of welded joints, a novel numerical analysis method based on the inherent strain theory is proposed to simulate the stress superposition of welding and subsequent UIT process of 304 stainless steel. Meanwhile, the experiment according to the process was carried out to verify the simulation of residual stress values before and after UIT. By the results, optimization of UIT application could effectively reduce the residual stress concentration after welding process. Residual tensile stress of welded joints after UIT is transformed into residual compressive stress. UIT formed a residual compressive stress layer with a thickness of about 0.13 mm on the plate. The numerical simulation results are consistent with the experimental results. The work in this paper could provide theoretical basis and technical support for the reasonable evaluation of the ultrasonic impact on residual stress elimination and mechanical properties improvement of welded joints.

The main benefits of submerging tiny-solid particles with the host fluid are to enhance the capability of storing heat, heat exchanger and interaction between the nanomaterials. The objective of this paper is to investigate the steady flow of bio-convective couple stress nanofluid across an inclined stretching cylinder with activation energy, motile microorganisms and nonlinear thermal radiation. The variable temperature conductivity and diffusivity impacts are considered. The Cattaneo–Christov double diffusion theory is also accounted in this model. The governing primary equations are reduced into a coupled system of ODEs by adopting appropriate similarity transformation. The resulting system is integrated numerically utilizing bvp4c tool via MATLAB software. The physical properties of concerned parameters against subjective profiles are examined through tabular and pictorial outline and then discussed in bit detail. It is shown that the velocity field reduces with growing estimations of Reynolds number and buoyancy ratio parameter. It is analyzed that thermal distribution decreases with improving amount of thermal relaxation parameter. Furthermore, concentration of nanoparticles is enhanced for larger amount of thermophoresis parameter. The microorganism field is up surged with enlarging amount of curvature and couple stress fluid parameters.

This paper focuses on the issue of fuzzy resilient control for synchronizing chaotic systems with time-variant delay and external disturbance. The goal is to design a fuzzy resilient controller with additive gain perturbations to guarantee that not only the drive and response systems are asymptotically synchronized in the absence of external disturbance, but also the synchronization error system has a prescribed disturbance attenuation index under the zero initial condition. By utilizing an appropriate Lyapunov–Krasovskii functional, the Bessel–Legendre inequality, and the reciprocally convex combination technique, a criterion on the stability and ${{\mathscr{H}}}_{\infty }$ performance of the synchronization error system is derived. Then, by means of some decoupling methods, a design scheme of the fuzzy resilient controller is developed. Finally, one numerical example is provided to examine the effectiveness of the fuzzy resilient controller design scheme.

This paper aims to study the effects of activation energy and thermal radiation in the bioconvection flow of nanofluid (third-grade nanofluid) containing swimming microorganisms in the presence of a heat source-sink past a stretching sheet. Brownian movement and thermophoresis diffusion are used in mathematical modeling. The given flow phenomenon is modeled in the form of governing partial differential equations. Furthermore, appropriate dimensionless transformation is used to transfer the governing system of PDEs into an ordinary one. The remodeled systems of ODEs are tackled numerically by bvp4c on Matlab with a shooting scheme in computational tool MATLAB. The bearing of prominently involved parameters on the numerical solution of velocity, temperature distribution, nanoparticles concentration and concentration of microorganisms is comprehensively discussed and elaborated through figures. It is established that velocity can be improved with a mixed convection aspect. Furthermore, the temperature and concentration of nanoparticles reduce against Prandtl number, also, large Peclet number declines the microorganisms field. The work contained in this paper has applications in nanotechnology, electrical and mechanical engineering, biomedicine, biotechnology, drug delivery, cancer treatment, food processing and various industries. No such work is yet reported, and it is good for the research in applied sciences.

The study of contagion dynamics in multilayer networks has become a hot topic. Networks have the characteristics of community structure. In this work, we present a comprehensive epidemic spreading model in multilayer networks with community structure. We consider the effects of population mobility, natural mortality and natural birth rate on population dynamics and contagion dynamics. The population size is determined by natural mortality and natural birth rate. The global and local epidemic thresholds are obtained. We analyze the factors which affect epidemic thresholds. The population mobility has no effect on the global epidemic threshold, but it can affect epidemic thresholds of each community. To control outbreaks of epidemics in influential communities can well control the spreading of diseases in the whole system. It is conductive to controlling outbreak of epidemics by reducing the internal average degree and interconnected links in influential communities. Numerical simulations on synthetic networks further support and enrich our conclusions.

The stability of the existence of the topological properties even in non-equilibrium condition such as irradiation of external time-periodic perturbation paves the way for designing and controlling the properties of materials. We study the change in the structure of the quasi-energy spectrum under the influence of the circularly polarized laser field with various intensities. The system is two-dimensional honeycomb nanoribbon of having zig-zag edges. Two cases where the onsite energies are present and absent are considered. We find that the topological phase transitions occur at some critical intensities of the laser field in both cases, which are recognized by the gap closing, the appearance of two crossing edge states, and sudden raise of the first Chern number from 0 to 1. The critical laser intensity is raised when either the frequency increases or the width of the ribbon decreases. Furthermore, band folding is observed in low-frequency domain in the quasi-energy spectrum and becomes more pronounced for the lower frequencies.

The era of SoC design has great dependency on CMOS circuits owing to its low power and high reliability which could contribute in the effective circuit designing. Here, a unique approach for the designing of voltage tunable current differencing transconductance amplifier (CDTA) is reported for the realization of Kerwin–Huelsman–Newcomb (KHN) filter. The proposed design has been simulated by using Cadence Virtuoso simulation tool with 0.18 $\mu$m technology parameters. This design is based on input voltage-based gain and frequency of operation tuning approach. In this reported design of filter, cutoff frequency can be tailored by input voltage instead of input current. This relaxes the need for the iterative circuit modifications to work in a particular frequency range. Thus, the reported CDTA design is expected to be robust and offers higher design flexibility as there is now no need of iterative designing and calibration in this approach. This also exhibits retained area requirement as per the current state of the art for the KHN filters. Further, the performance of designed CDTA-based KHN filter has also been verified with the existing KHN filters.

In this paper, the spin wave theory is applied to the one-dimensional Heisenberg antiferromagnet in the coexistence of two different anisotropies $D_1$ and $D_2$, which are separately the easy-axis single-ion anisotropies for sublattice A and sublattice B of the system. Both the ground-state and low-temperature properties of the system are strongly affected by the competition between these two anisotropies. Two kinds of the competition in terms of the deviation parameter $\mathrm{\Delta }=D_1-D_2$ are discussed for the uniform anisotropy taking the values of $D=D_1$ and $D=(D_1+D_2)/2$, respectively. The $\mathrm{\Delta }$-dependent behaviors (such as the power, exponential and linear laws) are obtained for the total magnetization, the staggered magnetizations, the internal energy, the specific heat and the susceptibility. It is found that at zero-temperature, the interplay between these two anisotropies induces the antiferromagnetic-disorder phase transition in the small anisotropy region with $D_1\ne D_2$. For the selected cases of $D_1=D_2$, our results for are in agreement with the findings obtained by the existing theories and the quantum Monte Carlo data.

The identification of influential nodes is one of the most significant and challenging research issues in network science. Many centrality indices have been established starting from topological features of networks. In this work, we propose a novel gravity model based on position and neighborhood (GPN), in which the mass of focal and neighbor nodes is redefined by the extended outspreading capability and modified k-shell iteration index, respectively. This new model comprehensively considers the position, local and path information of nodes to identify influential nodes. To test the effectiveness of GPN, a number of simulation experiments on nine real networks have been conducted with the aid of the susceptible–infected–recovered (SIR) model. The results indicate that GPN has better performance than seven popular methods. Furthermore, the proposed method has near linear time cost and thus it is suitable for large-scale networks.