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The current study aims to investigate heat transfer processes in chemically reacting processes, specifically focussing on the flow of an electrically conducting nanofluid over a curved extended surface. The work tries to describe the complex interaction between heat and mass transport phenomena in many applications, such as the biological sciences, catalytic processes and conflagration by including both homogeneous and heterogeneous processes in the framework. Introducing a convective heating strategy is a new technology that may boost circulation phenomena, perhaps leading to improved heat transfer performance. Additionally, the comparison between the Xue and Tiwari–Das models provides helpful insights into their individual suitability and precision in representing the heat transfer mechanism inside the examined system. The boundary layer approximation is used to handle the mathematical equations. Using the proper similarity variables, the controlling partial differential equations (PDEs) are effectively refined into the dimensionless form and computed numerically utilising the Runge–Kutta Fehlberg 4th–5th-order technique. The suggested characteristics of the physical parameters are examined and their relevant behaviour is illustrated graphically. The outcomes declare that the rise in magnetic parameter will decline velocity while enhance thermal profiles. Homogeneous and heterogeneous reaction strengths will decline the mass distribution while heat source/sink, solid fraction and Biot numbers will improve the temperature profile. In all circumstances, the Xue model exhibits a higher rate of thermal dispersion and temperature profile than the Tiwari–Das model. [ABSTRACT FROM AUTHOR]

The present work deals with warm inflationary scenario from the viewpoint of non-equilibrium thermodynamics. Due to the interacting two-fluid system, the dissipative mechanism in warm inflation can be considered as effective bulk viscous pressure in second-order non-equilibrium description of thermodynamics. It is found that the interaction term is proportional to the enthalpy density of the formed particles. The warm inflation has been analysed using slow-roll approximation and an expression for the interaction term has been obtained. The formulation of warm inflation in the non-equilibrium thermodynamical prescription has been presented as a lemma. Lemma 2 shows the inter-relation between slow-roll approximation and quasistable radiation bath using the Friedmann equations. Finally, warm inflation has been examined from the point of view of swampland conjectures. [ABSTRACT FROM AUTHOR]

This paper explores the effectiveness of the Lie derivative discretisation scheme applied to two particular types of nonlinear dynamical equations, both of which have the characteristic of time variables in the denominator position. The discrete structure of non-autonomous systems is established. In particular, we exclude time variables as state variables to prevent non-autonomous systems from becoming autonomous systems. Using this method, we compute the numerical solution of the system above and compare it with the precise solution and the numerical findings of Runge–Kutta, demonstrating the broad applicability of the Lie derivative numerical algorithm. Finally, we determine the CPU consumption time of two numerical algorithms, thus providing evidence of the high efficiency of the Lie derivative numerical algorithm. [ABSTRACT FROM AUTHOR]

In medical applications, carbon nanotubes (CNTs) are used as adaptable drug carriers for targeted delivery, utilising their ability to exactly encapsulate and release therapeutic compounds, and as contrast agents in cutting-edge imaging modalities like MRI and CT scans. The current investigation deals with the unsteady flow of hybrid nanofluid via an expanding/contracting surface. The flow of hybrid nanofluid for the conjunction of magnetisation, radiating heat and additional heat source energies the flow properties. The role of suction/injection is vital for the flow through the permeable medium. The hybrid nanofluid is a composite of single-wall carbon nanotube (SWCNT) and multi-wall carbon nanotube (MWCNT) nanoparticles in the base liquid water. Appropriate similarity transformation converts the governing PDEs to nonlinear ODEs. Further, these are handled numerically retaining shooting-based Runge–Kutta fourth-order technique. The physical consequence of various constraints affecting the flow are explained using graphs and numerical outcomes relating to rate coefficients are shown via tabular form. [ABSTRACT FROM AUTHOR]

The influence of various thermal properties of nanoparticles in several applications in industries, engineering, biomedical, etc. has gained the interest of researchers drastically. The current investigation aims in presenting the performance of various thermophysical properties, such as viscosity, conductivity, specific heat, etc. under the influence of various shapes of the nanoparticles on the flow of ternary hybrid nanofluid over an infinite vertical plate embedding within a permeable medium. The conducting fluid under an applied magnetic field with thermal radiation enriches the flow properties. Suitable similarity rules combined with similarity variables and stream function are adopted to transform the governing phenomena into a non-dimensional form. Further, analytical approaches, such as Laplace transformation technique is embraced for solving this unsteady system of equations. The graphs and tables present the physical behaviour of the contributing factors with a correlative result. The physical behaviour of these factors is described briefly and important outcomes are also depicted as a conclusive remark. It is observed that the enhanced magnetisation and heavier density of the ternary hybrid nanofluid decelerate the velocity distribution significantly whereas the cooling of the surface due to thermal Grashof number augments the fluid velocity. Further, the higher conductivity of the ternary nanofluid along with increasing thermal radiation increases the fluid temperature. [ABSTRACT FROM AUTHOR]

This article describes the bilinear form, biliear Bäcklund transformation and Lax pair of the geophysical Boussinesq equation using the Bell polynomial approach. The integrability of the said equation is asserted in the sense of the Lax pair. The Darboux transformation is employed to produce periodic solutions as well as single and N-complexiton-type solutions. Several steps of the Hirota bilinear technique are used to illustrate the flow characteristics of multi-solitons, higher-order breathers and rogue waves. Every sort of wave dynamics response to the Coriolis force is carefully studied. [ABSTRACT FROM AUTHOR]

The response of a nonlinear system excited by multi-frequency signals and Poisson white noise contains abundant dynamic behaviours. The study on system response has certain practical values. Utilising optimal dynamics response has unique advantages in weak feature identification under strong background noise. In this work, we study the optimal dynamics response in the bistable system excited by multi-frequency signals and Poisson white noise. The effects of noise parameters on system response and feature identification are discussed and analysed. Also, a signal identification method for unknown multi-frequency signals based on the optimal resonance response of the nonlinear system is proposed and applied to the compound fault diagnosis of rolling bearings, which utilises the difference between stochastic resonance and coherence resonance to determine characteristic components of the signals. The proposed method effectively identifies the characteristic components of the original excitation and avoids misjudgment caused by strong noise, which is effectively verified via simulation analysis and experiments. [ABSTRACT FROM AUTHOR]

In this paper, we apply the fractional homotopy perturbation transform method (FHPTM) to deliver an effective semi-analytical technique for determining fractional-order Kuramoto–Sivashinsky equations. The project technique combines the Laplace transform with the Caputo–Fabrizio fractional derivative of order α where α ∈ (0 , 1 ] . Fractional-order Kuramoto–Sivashinsky equation is indeed important in the field of nonlinear physics and mathematics. It is a fractional partial differential equation that describes the behaviour of waves in certain dissipative media, such as flames and chemicals. The FHPTM is described to be fast and accurate. Illustrative examples are included to demonstrate the efficiency and reliability of the presented techniques. [ABSTRACT FROM AUTHOR]

The present study investigates the three-dimensional convective rotating hybrid nanofluid flow over a linear stretching/shrinking sheet under the influence of dissipative heat. The behaviour of nanofluids, which are mixtures of Ag and MoS 4 nanoparticles in water in this study, is considered in the occurrence of convective flow and the impact of rotation. The linear stretching / shrinking sheet represents a common model in many industrial processes. The analysis also accounts for the effects of dissipative heat that arise due to viscous dissipation and Ohmic dissipation. A well-equipped set of transformations is used for the conversion of the non-dimensional form of the governing equations. Moreover, the adaptation of the Hamilton–Crosser conductivity model enhances the study due to enhanced physical properties. Further, the combined effect of nanofluid properties, convective flow, rotation and dissipative heat on the fluid flow and heat transportation features is examined followed by the numerical solutions adopted to find the solution of the transformed set of equations. The results obtained from this investigation will have potential implications for enhancing the use of nanofluid in industrial applications where efficient cooling of nuclear reactors, electronics cooling, automotive cooling systems, etc. are crucial. Further, use of nanofluid in optimising heat transfer processes in relevant engineering systems is vital. [ABSTRACT FROM AUTHOR]

This article presents the novel fractional-order Genesio–Tesi system, along with discussions of its boundedness, stability of the equilibrium points, Lyapunov stability, uniqueness of the solution and bifurcation. The efficient predictor–corrector approach is employed to quantitatively analyse the Genesio–Tesi system in fractional order. The findings enable conceptualisation and visualisation of the presented novel fractional-order Genesio–Tesi systems. The modified systems are proposed for future study on chaos control and applying the same for secure communication. Bifurcation analysis is carried out to see the variation in the system's behaviour from stability to chaos. The results of the bifurcation analysis support the results obtained for the stability of the equilibrium points. The system behaves chaotically since all the equilibrium points are unstable. The findings demonstrate a torus attractor for some of the suggested systems and a chaotic attractor for some of the novel fractional-order Genesio–Tesi systems. The system's torus attractor changes into a steady state when the order is reduced from integer to fractional. Changing the parameter values for one of the modified systems also shifts the system's behaviour, with the point attractor replacing the torus attractor. The point attractor of one of the systems changes into a steady character when the system's order is reduced from integer to fractional. The behaviour for one modified system is the same for fractional and integer orders. This discovery paves the way for the future study of the modified Genesio–Tesi system. This article gives a new direction to utilise these proposed Genesio–Tesi systems and study them extensively. The chaotic behaviour of the modified system can be used for secure communication. The synchronisation and chaos control of the modified system is recommended. [ABSTRACT FROM AUTHOR]

This paper presents a derivation of exceptional potentials for the novel angle-dependent (NAD) Coulomb potential. Exceptional potentials are a class of potentials with unique properties that can be used to study various physical phenomena. The use of exceptional polynomials is a powerful technique for solving differential equations, and the paper demonstrates its effectiveness in this context. [ABSTRACT FROM AUTHOR]

Organic scintillation detectors like BC501A, BC519, NE213, etc. have an inherent ability to classify neutrons and γ -rays through a process known as pulse shape discrimination (PSD). We developed a deep neural network (DNN)-based machine learning algorithm to discriminate neutrons / γ -rays. The algorithm was trained with data obtained from a BC501A detector considering the Cf-252 source. Further, to assess the performance of the DNN-based PSD algorithm, the algorithm was tested with an independent data set acquired with a different source-detector set-up, namely, BC501 detector with Am–Be source and a different digitiser. Results indicate that our proposed algorithm can successfully discriminate the neutrons and γ -rays with reasonably good accuracy for the independent data set. [ABSTRACT FROM AUTHOR]

The analysis and microcontroller implementation of a Newtonian fluid-filled porous medium heated from the bottom and subjected to sinusoidal or non-sinusoidal periodic gravity is investigated in this paper. The Newtonian fluid-filled porous medium with a bottom source of heat and subjected to periodic gravity modulation is described by the equation of conservation of energy and hydrodynamic equations modified following the Boussinesq–Darcy approximation. Galerkin-truncated approximation is applied in reducing the resulting set of partial differential equations into a Lorenz-like system of ordinary differential equations of order 1. The Lorenz-like system obtained in this case is found to have three equilibrium points whose stability depends on the system parameters. Without gravity modulation and by varying the scaled Rayleigh number, it is demonstrated that the obtained Lorenz-like system displays steady convection, periodic convection, chaotic convection, reverse period doubling to chaotic convection and coexistence between steady and chaotic convections. In the presence of sinusoidal or non-sinusoidal periodic gravity modulation and by varying the scaled Rayleigh number, the obtained Lorenz-like system exhibits periodic convections, bistable periodic convections and period doubling to chaotic convections. Finally, the existence of periodic convections, bistable periodic convections and chaotic convections is confirmed by microcontroller results obtained from the microcontroller implementation of the obtained Lorenz-like system. [ABSTRACT FROM AUTHOR]

Hybrid entangled states are necessary for quantum information processing within heterogeneous quantum networks. We develop an entanglement mechanism between continuous variable (CV) states of definite parity and delocalized photon (discrete variable (DV) state) leading to deterministic generation of the hybrid entangled states. The mechanism is realized by means of mixing of the input states on beam splitter (BS) with arbitrary transmission and reflection coefficients followed by measurement of the number of photons in the measurement mode by photon number resolving (PNR) detector. The scheme under study allows for one to partially control hybrid entanglement by change of the transmission/reflection coefficients of the BS. There are wide domains of values which guarantee the generation of maximum hybrid entanglement. The mechanism of the CV–DV entanglement can be used for controllable entangled state distribution in hybrid optical network. [ABSTRACT FROM AUTHOR]

This study investigates the effects of different shape factors of nanoparticles and thermal transfer on the velocity and thermal profiles of the MHD nanofluid flow. Here the MHD fluid flow problem is considered with multiple forms of nanoparticles having the volume fractions as an uncertain parameter using a triangular fuzzy number ranging from 0 to 4 % . A novel generalised double parametric-based fuzzy homotopy analysis method is employed to examine the effects of the different shapes of nanoparticles on the fuzzy velocities and temperature profiles in both convergent and divergent channels. Finally, the effectiveness of the proposed approach has been validated by comparing the obtained results with the available numerical results in crisp cases. [ABSTRACT FROM AUTHOR]

We investigate in this work, the inflationary scenario in viscous f(R, T) gravity formalism with mimetic potential and Lagrange multiplier. Considering that our universe contains beside a perfect fluid, a dark energy and a bulk viscous fluid, we obtain through the modified Friedmann equations a main differential equation that may describe the cosmological evolution in viscous mimetic f(R, T) gravity. For particular choice of the model f (R , T) = R + α R 2 + β T γ and for two forms of bulk viscosity coefficient, one as function of the Hubbe parameter H(t) and the other, as density dependent viscosity, we present a numerical results of the inflationary parameters such as the tensor-to-scalar ratio r and the scalar spectral index n s . A comparison of these results with observational data shows that our model can be used to describe the accelerated expansion of the universe. [ABSTRACT FROM AUTHOR]

Although the interactions between traffic flow and epidemic spread dynamics have been extensively studied, the impact of routing strategies on the susceptible–infected–recovered (SIR) epidemic spread driven by traffic flow have not received enough attention. In this paper, the traffic-driven SIR epidemic spread model under the probability path routing strategy and the efficient path routing strategy are studied. The instantaneous scale I p of the infected nodes’ density and the final scale R e of the ever infected nodes’ density are obtained through simulation, and it is found that there exist optimal values of routing parameters to minimise I p and R e , what is more, I p and R e under the probability path routing strategy are smaller than the values under the efficient path routing strategy. This means that the epidemic spreading can be effectively controlled by adjusting the routing strategy. In addition, when the routing parameter is the optimal value, the influence of packet generation rates, infection rates and cure rates on the epidemic spreading under different routing strategies is further discussed, and it is found that the higher the cure rate, the fewer nodes will be infected. Infected nodes’ density increases as the infection rate and packet generation rate increase, thereby accelerating epidemic spreading. These studies have certain guiding significance for controlling the spread of the epidemic. [ABSTRACT FROM AUTHOR]

In this paper, we use the homotopy perturbation transform method (HPTM) to offer an efficient semi-analytical technique for solving fractional Emden–Fowler equations. A mixture of Laplace transform, Caputo–Fabrizio derivative, and homotopy perturbation transformation process has the projected technique. To assess the efficacy of the suggested technique, test examples have been provided. The series have been used to represent semi-analytical solutions. Also, covered have the convergence position, estimation, and semi-analytical simulation results. The HPTM efficiently managed and controlled a series solution that quickly converges to a precise result in a narrow admissible region. The new findings essentially improve and simplify some of the previously published findings (see Malagia in Math. Comput. Simul. 190:362, 2021). By assigning appropriate values to free parameters, dynamical wave structures of some semi-analytical solutions are graphically demonstrated using 2-dimensional and 3-dimensional figures. Furthermore, various simulations are used to demonstrate the physical behaviors of the acquired solution with respect to fractional integer order. [ABSTRACT FROM AUTHOR]

Due to the numerous uses of nanofluids in industry and nanotechnology, scientists and engineers have given special attention to the subject of nanofluid mechanics. In the realm of fluid mechanics, it is a considerably more interesting research topic. Motivated by its useful applications in the rheological modelling of many important liquids, we seek to demonstrate the Jeffrey nanofluid model. The intention is to show the effects of multi-slip boundary condition of peristaltic flow in an asymmetric channel in the presence of viscous dissipation and bioconvection. Double diffusive convective flow is saturated with Jeffrey nanofluid containing gyrotatic micro-organism. The dimensional governing equations are converted into non-dimensional forms by suitable dimensionless parameters. The analytical method has been used to obtain solutions for the non-dimensionless system. The impact of different physical characteristics on velocity, temperature, concentration, volume fraction and trapping phenomenon has been analysed through graphs. From the study, it is observed that the velocity slip parameter increases the velocity profile, whereas the velocity profile decreases in the case of bioconvection Rayleigh number, double-diffusive and nanofluid buoyancy ratio, and it is also noticed that the density of the motile micro-organism is lowered by the Peclet number and for bioconvection constant. The present study is useful in academic research, biomedicine and theoretical studies of hemodynamics, and also micro-organisms that are favourable in maintaining the ecosystem and human health. In a few cases, the current analysis shows a substantial agreement with previously published results. [ABSTRACT FROM AUTHOR]

The survival of endangered languages in complex language competition depends on the socio-cultural status and honour endowed (by itself and by the other) among them. The restriction in the endorsement of this honour leads to the extinction of one language and rise of the other. Endorsing proper mutual honour to each other triggers the co-existence of people speaking the two languages and this can save both languages from extinction. The loss of respect to each other leads to the death of both languages. We found a minimal or critical mutual honour u c which protects the two languages from extinction. The increase in mutual honour from this minimal value allows an increase in the populations of the people who speak the two languages. The state of co-existence of competing languages abolishes the concept of minority and majority in language competition, which can be obtained by mutual honour. Further, excess of biased honour to a particular language (minority or majority) forces the language to extinct. In mean-field approximation of language competition, magnetisation parameter can be taken as an indicator of the survival of a language. [ABSTRACT FROM AUTHOR]

In this study, electro-optical and electronic properties of 4-n-alkoxy-4 ′ -cyanobiphenyl liquid crystal homologous series was explored. The effect of the number of carbon atoms present in the alkoxy chain on the electro-optical parameters and global reactivity descriptors has been investigated in the presence of applied electric field. Further, these parameters have also been studied under varying electric field for the homologue number, n = 8 –12. Most of the parameters exhibit odd–even effect for a certain range of homologous numbers. The variation of the homologous number in the electric field is demonstrated to have a considerable impact on these outcomes. [ABSTRACT FROM AUTHOR]

The pulse-shaped explosion (abbreviated as PSE) behavior, represented as the system roots pulse-shaped quantitative changing sharply, is a new way to the bursting oscillations proposed recently. In the present paper, the complex bursting oscillation patterns triggered by the PSE and integer frequency ratios are considered based on a Rayleigh–van der Pol system (abbreviated as RVDPS) excited by the parametrical and external forces. Two cascade bursting oscillations, the cascade supHopf/supHopf bursting oscillations induced by the integer frequency ratios and the cascade supHopf/supHopf bursting oscillations with multiple PSE/PSE hysteresis loops induced by the integer frequency ratios and PSEs, are investigated. We show that the PSEs occur when the system solution curve approaches to infinity at some certain values and the PSEs do not change the stabilities of the attractors. In addition, we find that the frequency and period of the cascade bursting oscillation patterns equal to that of the external force. Our study proposes a new PSE type to the bursting oscillations named the cascade PSEs and increases two cascade bursting oscillation patterns. [ABSTRACT FROM AUTHOR]

In this study, we used the generalised exponential rational function method (GERF method) to find a new family of solitary wave solutions of the modified chemotaxis equation accounting for short-range and long-range diffusion. The presented solutions exhibit various classes of solitary waves, i.e. bell-shaped and kink–antikink solitary wave solutions under certain constraint relations. We have used a different source function for the attractant as well as species density taking inspiration from the existing models. We have also presented 3D and 2D plots to explain the behaviour of the obtained family of solutions. [ABSTRACT FROM AUTHOR]

In this work, a GaAs wedge-shaped quantum dot (WSQD) is considered. In the first step, we theoretically investigated the magnetocaloric effect, magnetic susceptibility and heat capacity of WSQD without considering impurity. In the next step, we calculated the binding energy and optical properties of the WSQD under various factors, such as impurity position, temperature and pressure. For our results, we first solved the Schrödinger equation to determine the energy levels and eigenstates of the system. Then, the influence of impurity position, temperature and pressure on optical absorption coefficients (ACs) and refractive index changes (RICs) were investigated. The temperature dependence of the magnetic entropy changes (magnetocaloric effect) shows a pronounced minimum at low temperatures. The magnetic susceptibility shows both positive (paramagnetism) and negative values (diamagnetism) for different parameters. The impurity position has a key role in the electronic properties, ACs and RIs of a WSQD. The ACs and RICs enhance and shift towards lower energies under pressure. Also, the optical properties reduce in the presence of impurity. [ABSTRACT FROM AUTHOR]

In this article, the heat transfer of Al 2 O 3 –Cu/H 2 O in the magnetohydrodynamic (MHD) stagnation point flow in the direction of an exponentially stretching/shrinking sheet with the effect of heat source, thermal radiation and viscous dissipation is examined. The inclusion of dissipative heat, thermal radiation and additional heat source enriches the study as well. Using suitable similarity transformations, the governing partial differential equations are transformed into ordinary differential equations (ODEs). The ODEs are solved numerically by the built-in function bvp4c in MATLAB. By the addition of nanoparticle, effects of various parameters were studied, and the outcomes revealed that the skin friction coefficient decreases and the local Nusselt number increases. In comparison, viscous dissipation causes an improvement in the fluid thermal state and, as a result, triggers the thermal boundary layer to rise. [ABSTRACT FROM AUTHOR]

A quantum version of the linear cryptanalysis technique is presented in this paper. So far, only a certain part of some classical cryptanalysis techniques was converted for quantum processing to gain speed-up while analysing a symmetric primitive. However, none of the quantum version of these attacks, including linear cryptanalysis, completely uses quantum computing for all the steps. We developed a quantum version for all the steps of the linear cryptanalysis. The proposed quantum linear cryptanalysis is applied on the quantum version of a toy cipher. Performance analysis shows that the quantum version of the linear cryptanalysis offers quadratic speed-up in different steps of the attack. It can be used to attack any cipher that is vulnerable against linear cryptanalysis. [ABSTRACT FROM AUTHOR]

We study the dynamics of a Brownian particle in Morse potential under thermal fluctuations, modelled by Gaussian white noise whose amplitude depends on absolute temperature. Dynamics of such a particle is investigated by numerically integrating the corresponding Langevin equation. From the mean first passage time (escape time), we study the dependence of Kramer’s rate on temperature and viscosity of the medium. An approximate analytical expression for the rate constant is found by solving differential equation for the mean first passage time. The expression shows a temperature dependent pre-factor for the Arrhenius equation. Our numerical simulations are in agreement with the analytical approximations. [ABSTRACT FROM AUTHOR]

In this paper, we deal with locally rotationally symmetric Bianchi type-I cosmological model with varying cosmological constant. Here, we have considered two models. In Model I, we have analysed total linear stability analysis for linear coupling between the dark sector of the Universe whereas in Model II, the quadratic coupling between the dark sector of the Universe is considered. The cosmological history of the models is studied by finding all the critical points and analysing their local stability. We study the behaviour of all the critical points of the model when they are hyperbolic in nature using the linear Jacobi stability analysis and when they are non-hyperbolic in nature using centre manifold theory. The perseverance of the equilibrium points is illustrated in phase portraits. [ABSTRACT FROM AUTHOR]

By taking a low-frequency excited modified Chua's circuit model with discontinuous vector field as an academic example, this paper introduces the periodic bursting patterns characterised by stick–slip motions as well as the underlying generation mechanism uniquely belonging to Filippov-type slow–fast dynamical systems (FSFDSs). Based on the tangencies and the visibilities, this paper is the first to clearly explain the unique transition routes to bursting phenomena involving stick–slip motions by introducing the subdivisions of the sliding region. The results indicate that such transition routes are heavily dependent on the local structures of pseudoequilibrium (PE), performing distinct non-conventional bifurcation schemes. Furthermore, two transition routes respectively corresponding to a stable node-type PE and a stable focus-type PE as well as the induced periodic bursting oscillations are further discussed in numerical simulations. Particularly, it should be pointed out that the second one is a novel route to bursting oscillation in FSFDSs. [ABSTRACT FROM AUTHOR]

The Coulomb fission may take place in a reaction if the maximum Coulomb excitation energy transfer exceeds the fission barrier of either the projectile or the target nucleus. This condition is satisfied in all the reactions used for the earlier blocking measurements of fission time-scale except for the reaction 208 Pb + natural Ge crystal, where the time-scale is below the measurement limit of the blocking technique < 1 as. Inclusion of Coulomb fission in the data analysis of the blocking experiments leads us to interpret the measured time-scales longer than a few attoseconds (as) (about 1–2.2 as) due to slow Coulomb fission and those shorter than 1 as, as due to quasifission and fast Coulomb fission. Consequently, this finding resolves the critical discrepancies between the fission time-scales measured using the nuclear and blocking techniques. This, in turn, validates the fact that the quasifission and fast Coulomb fission time-scales are indeed of the order of zeptosecond (zs) in accordance with the nuclear experiments and theories. The present results thus provide an essential input to the understanding of the fusion evaporation reaction during the formation of heavy elements. [ABSTRACT FROM AUTHOR]

The energy of a mechanical system as well as other invariants can be obtained using a complementary variable formulation. This approach is extended here to systems with a dissipative force. The damping coefficient depends linearly on the velocity, but is allowed to have an arbitrary time dependence. An invariant Q 00 is obtained in terms of linearly independent solutions. A semipositive definite version of this quantity is the Ermakov invariant. This scenario including damping, allow us to give a physical meaning to a closely related quantity E ω ex = 1 2 m q 00 , which is the energy exchanged between the kinetic and potential energies per unit frequency, or E t ex = 1 2 κ q 00 which is the energy exchange per period. The q 00 exchange energy is positive under light damping. Under critical or heavy damping, when no oscillations occur, q 00 is either zero or negative. Thus, q 00 ≥ 0 is a measure of the back and forth energy exchange. This periodic energy transfer is compared with the usual oscillator energy of the damped system. To this end, the kinetic energy is split into conservative and dissipative terms. The energy ripples superimposed in the exponential decay are described by a dissipative modulation term. In the vein of Ermakov’s formalism, the amplitude and phase nonlinear differential equations are derived for a time-dependent damped system. The complementary variables and Ermakov formalisms are then compared. [ABSTRACT FROM AUTHOR]

This study concerns the control of uncertain fractional-order multi-inputs chaotic systems, using fractional dynamic sliding mode controller (FD-SMC). This controller removes the chattering of the system using a low-pass integrator fractal filter beforehand, which provides an augmented system with extra dimension. Hence, the dimension of the system state is more than the original system. These augmented state variables are known to implement FD-SMC. To solve this challenge, a novel fractional sliding observer (FSO) is constructed and used in this study. The theory of Lyapunov is applied to construct the stability of both the proposed FSO and FD-SMC. Comparison is also presented with conventional fractional sliding mode controller (CF-SMC). To have a reliable comparison, the proposed FSO is implemented in both FD-SMC and CF-SMC. This study demonstrates the advantage of the FD-SMC in removing the chattering, its simplicity in the concept and realisation, with CF-SMC where the chattering is usually present. Another advantage of the proposed FD-SMC is appeared in the coefficient of the sign function (switching gain), which is independent of the model uncertainties. Finally, an improved multi-inputs fractional order Duffing–Holmes chaotic system (FO-DHCS) is proposed to validate this novel approach using simulation examples. The illustration of the simulation results shows a better performance of this proposed approach. [ABSTRACT FROM AUTHOR]

This study investigates the thermal characteristics and irreversibility analysis of the combined electro-osmotic and electromagnetic flow of a couple stress fluid through a microfluidic channel with constant wall heat flux boundary condition. The analytical solutions for electromagnetohydrodynamic (EMHD) flow velocity, temperature field and entropy production distribution are obtained using the physically relevant boundary conditions. Results show the effects of several factors, including couple stress parameter, Hartmann number, lateral/transverse electric field parameter and Brinkman number on the temperature transport and entropy generation, particularly, the details of how the temperature, Nusselt number and entropy generation vary with these parameters. The results demonstrate that the entropy generation in the channel is strongly dependent on the flow velocity and thermal energy distribution. In this analysis, the primary focus is placed on the impact of the couple stress parameter on EMHD flow velocity, heat transfer and entropy generation. The results reveal that when the couple stress physical parameter increases, the magnitude of temperature and Bejan number decreases. However, the Nusselt number and entropy production rates have opposite effects towards the channel walls. The present research has enormous practical significance and can design efficient thermal micro/nanoequipment. [ABSTRACT FROM AUTHOR]

The approximate phase-equivalent potentials to Manning–Rosen one are constructed using supersymmetric algebra. Using supersymmetric factorisation method, four SUSY transformations T 1 , T 2 , T 3 and T 4 are operated in pairs on Manning–Rosen potential to construct three different phase-equivalent potentials. These methodologies are verified by computing scattering phase shifts for different partial waves of nucleon–nucleon and α –nucleon systems using the newly constructed phase-equivalent potentials. Good agreement with standard phase-shift data proves the merits of our approaches. [ABSTRACT FROM AUTHOR]

Inflationary model driven by a scalar field whose potential has a step in the second derivative with respect to the field is considered. For the best-fit potential parameter values, the 3-point function and the non-Gaussianity associated with the featured model is calculated. We study the shape and scale dependence of the 3-point function. The distinctive feature of this model is its characteristic ringing behaviour of f NL . We can see that the oscillations in f NL in this model last for a much longer range of k values, than the previously studied models. In that sense, this model is potentially distinguishable from models with other features in the potential. [ABSTRACT FROM AUTHOR]

The effects of two kinds of time-delayed feedbacks and non-Gaussian coloured noise on modulating bifurcations in a birhythmic model have been investigated. The non-Gaussian coloured noise is approximated as an Ornstein–Uhlenbeck process using the path integral approach. Subsequently, by the conjoint of the multiscale method and random average technique, the stationary probability density function (SPDF) of the amplitude is obtained. It is concluded that either in the condition of determinacy or randomness, time delays can effectively control birhythmicity. Especially considered the presence of noise, the varying displacement delay results in multiple bifurcation in the case of single delay, while the velocity delay triggers more complex bifurcation behaviour in the case of double delays. The strength and correlation time of noise present the opposite impacts on bifurcation, so do the two delayed coefficients. Bifurcation under different excitations is analysed theoretically, and the correctness is verified by numerical simulation. Many abundant bifurcations are available by adjusting the time-delayed feedbacks and noise intensity, which may be conductive to achieve the expected phenomenon in the enzymatic–substrate reactions. [ABSTRACT FROM AUTHOR]

In this paper, we show that the q-deformation scheme applied on both sides of the difference equation of the logistic map is topologically conjugate to the canonical logistic map and therefore there is no dynamical changes by this q-deformation. We propose a correction on this q-deformation scheme and apply it on the logistic map to describe the dynamical changes. We illustrate the Parrondo's paradox by assuming chaotic region as the gain. Further, we compute the topological entropy in the parameter plane and show the existence of Li-Yorke chaos. Finally, we show that in the neighbourhood of a particular parameter value, q-logistic map has stochastically stable chaos. [ABSTRACT FROM AUTHOR]

This work concerns the modelling of the dynamics of polarisation of a centrosymmetric material subjected to an amplitude-modulated excitation (AME). The dynamic equation obtained for the polarisation is the Duffing equation with nonlinearities of orders 3 and 5. With the multiple scale method, the nonlinear resonances are studied. Periodic, multiperiodic, quasiperiodic and chaotic behaviour have been checked using the bifurcation diagram, Lyapunov exponent, phase space, Poincaré section and vibrational resonance using the fourth-order Runge–Kutta integration algorithm. The effects of various parameters of polarisation are analysed and very interesting results are obtained. The results obtained by the analytical methods are validated and complemented by the numerical simulations. [ABSTRACT FROM AUTHOR]

In this paper, a numerical scheme based on quintic B-spline collocation method using the Strang splitting technique is presented for solving the generalised Rosenau–regularised long wave (RLW) equation given by appropriate initial-boundary values. For this purpose, firstly the problem is split into two subproblems such that each one includes the derivative in the direction of time. Secondly, each subproblem is reduced to a system of ordinary differential equations (ODEs) using collocation finite-element method with quintic B-splines for spatial integration. Then, the resulting ODEs for time integration are solved using the Strang time-splitting technique with the second order via the usual Runge–Kutta (RK-4) algorithm with the fourth order. To measure the accuracy and efficiency of the present scheme, a model problem with an exact solution is taken into consideration and investigated for various values of the parameter p. The error norms L 2 and L ∞ together with the invariants of discrete mass Q and discrete energy E have been computed and a comparison is given with other ones found in the literature. The convergence order of the present numerical scheme has also been computed. Furthermore, the stability analysis of the scheme is numerically examined. [ABSTRACT FROM AUTHOR]

Breakup reactions at deep sub-barrier incident energies are the less investigated in the breakup of loosely-bound systems. Motivated by a recent study by Pakou et al (Phys. Rev. C102:031601(R), 2020), we further analyse the breakup of 8 B nucleus on a lead target at deep sub-barrier incident energies. It is found that at these energies, continuum–continuum couplings enhance the breakup cross-section. These couplings are otherwise known to hinder the breakup cross-section at energies around and above the Coulomb barrier. We argue that this enhancement can in part explain the known predominance of the breakup channel over other reaction channels at deep sub-barrier energies, and that it may signal a breakup on the outgoing trajectory. The results in this paper also confirm the prediction in the reference above. Due to the astrophysical aspect of 8 B nucleus, this result could have significant implication in nuclear astrophysics. [ABSTRACT FROM AUTHOR]

By using the theory of group-invariant solutions, the symmetries of the motion equation of plane curve in S L ′ (2) geometry is presented. Group-invariant solutions associated with one-dimensional optimal system are obtained and classified. [ABSTRACT FROM AUTHOR]

We discuss Z-production in deep inelastic scattering e + p → e + Z + X using the parton model, in the context of the Standard Model at leading order. In contrast to the deep inelastic ep-scattering ( e + p → e + X ), where Q ~ 2 , the momentum transfer square, is unambiguous, in the case of boson production it depends upon the mechanism involved, that is, it is related to the electroweak interactions. We present estimates for the total cross-section as a function of s , the energy of the ep system, in the range 300 ≤ s ≤ 1300 GeV, and also for different assignements of Q ~ 2 . [ABSTRACT FROM AUTHOR]

We study the symmetry and integrability of a modified Camassa–Holm equation (MCH), with an arbitrary parameter k, of the form u t + k (u - u xx) 2 u x - u xxt + (u 2 - u x 2) (u x - u xxx) = 0. The commutator table and adjoint representation of the symmetries are presented to construct one-dimensional optimal system. By using the one-dimensional optimal system, we reduce the order or number of independent variables of the above equation and also we obtain interesting novel solutions for the reduced ordinary differential equations. Finally, we apply the Painlevé test to the resultant nonlinear ordinary differential equation and it is observed that the equation is integrable. [ABSTRACT FROM AUTHOR]

This study deals with the generalised Kudryashov method (GKM) for the time-fractional generalised Burgers–Fisher equation (TF-GBF). Using the transformation of travelling wave, the TF-GBF is transformed into a non-linear ordinary differential equation (NLODE). Later, GKM has been applied in the resultant equation which is a novel technique to obtain exact solutions. These exact solutions are plotted and the power series solution is also derived. [ABSTRACT FROM AUTHOR]

In this paper we report the control and synchronisation of chaos in a memristive Murali–Lakshmanan–Chua (MLC) circuit. This circuit, introduced by the present authors in 2013, is basically a non-smooth system having two discontinuity boundaries by virtue of it having a flux-controlled active memristor as its nonlinear element. While the control of chaos has been effected using state feedback techniques, the concept of adaptive synchronisation and observer-based approaches have been used to effect synchronisation of chaos. Both these techniques are based on state space representation theory which is well known in the field of control engineering. As in our earlier works on this circuit, we have derived the Poincaré discontinuity mapping (PDM) and zero time discontinuity mapping (ZDM) corrections, both of which are essential for realising the true dynamics of non-smooth systems. Further, we have constructed the observer- and controller-based canonical forms of the state-space representations, have set up the Luenberger observer, derived the controller gain vector to implement state feedback control and calculated the gain matrices for switch feed back and finally performed parameter estimation for effecting observer-based adaptive synchronisation. Our results obtained by numerical simulation include time plots, phase portraits, estimation of the parameters and convergence of error graphs and phase plots showing complete synchronisation. [ABSTRACT FROM AUTHOR]

We consider a deformed fifth-order Korteweg–de Vries (D5oKdV) equation and investigated its integrability and group theoretical aspects. By extending the well-known Lax pair technique, we show that the D5oKdV equation admits a Lax representation provided that the deformed function satisfies certain differential constraint. It is observed that the D5oKdV equation admits the same differential constraint (on the deforming function) as that of the deformed Korteweg–de Vries (DKdV) equation. Using the Lax representation, we show that the D5oKdV equation admits infinitely many conservation laws, which guarantee its integrability. Finally, we apply the Lie symmetry analysis to the D5oKdV equation and derive its Lie point symmetries, the associated similarity reductions and the exact solutions. [ABSTRACT FROM AUTHOR]

Due to the exponential attenuation of photons in materials, thick samples will attenuate a large portion of photons. This is a source of error in methods such as neutron activation analysis, which use gamma spectroscopy to characterise a radioactive source. A method is developed to quantify the magnitude of self-shielding with the help of MCNP6. Then the mass of an unknown sample is determined by comparing the known sample mass and the photopeak counts of the unknown and the known samples following activation. The inclusion of self-shielding effects is shown to make this comparative mass analysis measurement technique more accurate. Accounting for the self-shielding effects allows the true source, instead of the shielded source, to be resolved by correcting for the photons that are attenuated as they try to escape the sample and reach the detector. The γ -ray measurements were made using several samples of varying shapes. [ABSTRACT FROM AUTHOR]

The amines are major source of environment pollutants emitted in atmosphere from various anthropogenic sources. The non-thermal plasma (NTP)-based technology has proved successful in controlling the emitted amines reaching the atmosphere. The efficient NTP reactors rely on accurate electron–molecule collision data. The electron impact cross-sections are thus obtained for a few amines from ionisation threshold to 5000 eV using the single centre expansion (SCE) formalism. The molecular wave function of each target is obtained from the multicentre expansion of the Gaussian-type orbitals within a single determinant Hartree–Fock self-consistent field scheme. The expansion of wave function, density and potential is carried out at the centre of mass of the molecules. The interaction potential included to model the electron interaction in the target comprises static, correlation-polarisation and exchange types of potentials. The elastic cross-sections are obtained after solving the coupled scattering equations using Volterra integral form. The inelastic effects contributing to electron–molecule scattering are approximated by the ionisation cross-sections. The total cross-sections obtained after summing the elastic and ionisation cross-sections are in good agreement with the available data. We have also tried to explain the effect of polarisation potential on scattering cross-sections. A semiempirical formula based on the spatial extent of the molecule is proposed to estimate the cross-sections for the homologous series of amine molecules. [ABSTRACT FROM AUTHOR]

The nonlinear propagation of dust-acoustic waves (DAWs) and associated dust-acoustic rogue waves (DARWs), which are governed by the nonlinear Schrödinger equation, is theoretically investigated in a four-component plasma medium containing inertial warm negatively charged dust grains and inertialess non-thermal distributed electrons as well as isothermal positrons and ions. The modulationally stable and unstable parametric regimes of DAWs are numerically studied for the plasma parameters. Furthermore, the effects of temperature ratios of ion-to-electron and ion-to-positron, and the number density of ion and dust grains on the DARWs are investigated. It is observed that physical parameters play very crucial roles in the formation of DARWs. These results may be useful in understanding the electrostatic excitations in dusty plasmas in space and laboratory situations. [ABSTRACT FROM AUTHOR]

Vibrational resonance is studied in a fractional Mathieu–Duffing oscillator with two types of time delays: fixed and distributed delays. The theoretical expression of the response amplitude is obtained by utilising the method of direct partition of slow and fast motions. Relative errors between the theoretical prediction and the numerical simulation are introduced to verify the validity of analytical approaches. The relative error of the displacement and the relative error of the response amplitude are calculated. Small relative errors show that the theoretical analysis is statistically correct. Therefore, the effects of fractional order, linear stiffness coefficient, low-frequency signal, time delay intensity and damping coefficient on the Mathieu–Duffing oscillator with distributed delay are studied successively. In order to better illustrate the impact of distributed time delay on the model, the case of fixed time delay is analysed and compared, and it can be found that the distributed delay has more significant influence than fixed delay on the system. In addition, the influence of distributed delay on the system is more significant than that of the fixed delay. [ABSTRACT FROM AUTHOR]