Pramana最新文献

{"title":"Impacts of the Soret number, Dufour number, binary chemical reaction, Arrhenius activation energy and magnetohydrodynamics on the Williamson fluid over a circular porous stretching sheet in the presence of radiation","authors":"Ankur Kumar Sarma,&nbsp;Dipak Sarma,&nbsp;Sunmoni Mudoi","doi":"10.1007/s12043-025-02938-z","DOIUrl":"10.1007/s12043-025-02938-z","url":null,"abstract":"<div><p>This paper examines the effects of nonlinear radiation, heat sources, binary chemical reactions, Soret number, Dufour number and Arrhenius activation energy on Williamson fluid, as well as the transport of heat and mass via a circular porous radially stretched sheet using magnetohydrodynamics (MHD). It also applies a changing magnetic field to the circular, porous, stretched sheet. The similarity transformation transforms the nonlinear controlling boundary layer partial differential equations (PDEs) of momentum, temperature and concentration into a set of nonlinear ordinary differential equations (ODEs). The MATLAB bvp4c method then numerically solves the ODEs. We use graphs to illustrate the variations in flow, heat and concentration profiles resulting from various problem-related parameters, such as the Weissenberg number, magnetic parameter, Prandtl number, heat source, Eckert number, Soret number, Dufour number, radiation, temperature ratio, activation energy and chemical reaction parameters. We showed the effects on the skin friction coefficient, heat and mass transfer rate using tables for various values. When the porosity parameter, magnetic parameter and Weissenberg number increase, the fluid velocity drops. The temperature of the fluid increases as the Weissenberg number rises. As the activation energy parameter increases, the concentration profile increases. When compared to previous studies, the new results are considered quite good. Additionally, this work offers an intuitive explanation of the nonlinear radiation events in the Williamson fluid. With the ability to increase thermo-fluid flow system efficiency, the Williamson fluid has several applications in food industry, biomedicine and engineering appliances.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 3","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145143698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Potential alteration of the bottomonium states in XeXe collisions","authors":"Abdulla Abdulsalam,&nbsp;Eman Aljuhani","doi":"10.1007/s12043-025-02953-0","DOIUrl":"10.1007/s12043-025-02953-0","url":null,"abstract":"<div><p>Researchers have investigated the suppression and survival of bottomonium in relativistic Heavy-Ion Collisions (HIC) to understand Quark-Gluon Plasma (QGP) characteristics better. The interplay between dissociation and recombination in QGP is typically explored using the Boltzmann transport equation, with a particular focus on the dissociation rates of newly formed bound states. This study considers the cumulative effects of gluon-induced dissociation, colour screening and recombination on bottomonium production in HIC. The model uses parameters of Xenon-Xenon (XeXe) collisions at <span>(sqrt{s_{text {NN}}} = 5.44)</span> TeV from the Large Hadron Collider (LHC). By employing the Bateman solution method to calculate recombination rates, this research provides a detailed analysis of the recombination and dissociation dynamics of the QGP and how they impact the bottomonium states in medium-sized collision systems like XeXe. The model successfully explains the observed suppression of <span>(Upsilon (nS))</span> states in such a system.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 3","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145165424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamics of network growth and evolution: integrating non-constant edge growth, mixed attachment and reciprocity","authors":"Jan Medina-López,&nbsp;Diego Ruiz","doi":"10.1007/s12043-025-02935-2","DOIUrl":"10.1007/s12043-025-02935-2","url":null,"abstract":"<div><p>Advancements in network science research have enriched our understanding of the mechanisms shaping the topological properties of networks over the past two decades. However, the existing models still grapple with limitations in fully capturing the diverse structures and behaviours observed in real-world networks. This paper addresses these limitations by examining network growth in networks characterised by a distinct in-degree distribution, exhibiting expected new edges in the head and an extended exponential or power-law behaviour in the tail. To overcome these complexities, we propose a comprehensive model encompassing non-constant edge establishment driven by mixed attachment and reciprocal mechanisms. This extension offers a more accurate representation of real-world networks. Utilising various discrete probability distributions, including Poisson, binomial, zeta and log-series, our model accommodates variations in the number of new edges, providing a realistic depiction of network evolution. Analytical expressions for the limit in- and out-degree distributions and evolving dynamics of cumulative complementary in- and out-degree distributions are derived. These findings enable a detailed assessment of each mechanism’s contribution to the head and tail of the in- and out-degree distributions. Furthermore, we validate the practical relevance of our model by fitting it to real-world networks, emphasising the impact of the number of new edges and reciprocity.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 3","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145165913","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigating nonlinear wave structures via auto-Bäcklund transformation and Hirota bilinear method in the coupled Boussinesq system","authors":"Snehalata Nasipuri,&nbsp;Prasanta Chatterjee","doi":"10.1007/s12043-025-02936-1","DOIUrl":"10.1007/s12043-025-02936-1","url":null,"abstract":"<div><p>We investigate various nonlinear wave structures of the coupled Boussinesq system (CBS) using two efficient techniques: the auto-Bäcklund transformation and the Hirota bilinear method (HBM). Various travelling wave solutions, including kink waves, solitary waves with lump excitation and multi-shock waves, are obtained for the CBS using the auto-Bäcklund transformation. We also obtain the interaction between two-soliton solutions utilising this technique. Initially, we have shown that the CBS passes the Painlevé test for integrability. Then, we derive the auto-Bäcklund transformation for CBS through the truncated Painlevé expansion. Next, we observe the interaction and propagation behaviours of multi-soliton solutions for CBS using the HBM. The existence of multi-soliton solutions establishes that the CBS is also integrable in the Hirota sense. Interestingly, we observe that the HBM offers a more comprehensive framework for exploring diverse interactions between bright solitons and dark solitons, compared to the auto-Bäcklund approach. The multi-solitons and solitary waves with lump excitation obtained in this study can be used to describe surface water waves, while the kink wave and multi-shock waves represent topological changes in the water surface modelled by the CBS. Our findings on nonlinear structures for the CBS, provide valuable insights into the behaviour of nonlinear waves in water dynamics and are important for analysing various phenomena, such as ocean waves and waves in coastal areas.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 3","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145165914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New analytical solutions of the ((3+1))-dimensional generalised B-type Kadomtsev–Petviashvili equation","authors":"Ruchi Kaur,&nbsp;Sukhjit Singh,&nbsp;Dharmendra Kumar","doi":"10.1007/s12043-025-02942-3","DOIUrl":"10.1007/s12043-025-02942-3","url":null,"abstract":"<div><p>Genralised B-type Kadomtsev–Petviashvili (gBKP) equation corresponds to the weak dispersive nature of the propagating waves in quasi-media and fluid mechanics. In this paper, a collection of exact soliton and periodic wave solutions are obtained for the (<span>(3 + 1)</span>)-dimensional gBKP equation using the well-known generalised exponential rational function (GERF) method. Several classes of exact soliton and periodic solutions are derived using trigonometric and hyperbolic functions by employing this method. A graphical representation of the solutions is also presented to analyse the dynamics of the system. With the help of the computational software Mathematica, the visualisations for the wave configuration of various solutions are presented using three- and two-dimensional plots. The plots represents the wave profile of a wide range of singular soliton, multi-solitons and periodic solitons obtained for the considered equations by taking appropriate values for the associated parameters. The collection of solutions listed in the article signify the importance and possible application of GERF method to a wide variety of nonlinear differential equations in physical phenomena.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 3","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145165322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Temperature evolution of the FRW Universe in the viscous generalised Chaplygin gas model","authors":"Abhinath Barman","doi":"10.1007/s12043-025-02959-8","DOIUrl":"10.1007/s12043-025-02959-8","url":null,"abstract":"<div><p>In this paper, we study the temperature evolution of the Friedmann–Robertson–Walker (FRW) Universe filled with viscous generalised Chaplygin gas (VGCG) as a model of dark energy. We started the thermodynamical treatment of the VGCG, which is given by the equation of state <span>(p=-frac{A}{rho ^{alpha }})</span> with bulk viscosity in the framework of the Eckart theory. We investigated it in the cosmological model using the FRW metric in flat space–time, and we were able to determine its temperature as a function of redshift <i>z</i>. Besides, the expression for the fluid’s temperature in terms of redshift and the viscosity parameter <span>(xi _{0})</span> is derived. In our computation, we assumed that the value of the parameter <span>(Omega _{x})</span> would be 0.7 and that the current value of the temperature of the microwave background radiation would be given by <span>(T_{0}=2.7)</span> K. Using the decoupling redshift value <span>((zapprox 1100))</span> and the viscous parameter, the decoupling temperature is computed. The optimum choices for the remaining parameters are <span>(alpha =0.25)</span>, <span>(Omega _{x}=0.75)</span>, <span>(xi _{0}=-0.1930)</span>, yielding a decoupling temperature of <span>(T(z=1100)approx 4000)</span> K and a redshift of <span>(zapprox 0.25)</span>. We also compute the decoupling temperature in this model at <span>(ddot{a}=0)</span> and <span>(T_{0}=2.7)</span> K. In terms of <i>z</i> and <span>(xi _{0})</span>, we also examined other parameters, such as the Hubble parameter, the equation of state parameter, the adiabatic speed of sound, jerk, snap and Om diagnostic parameters. These values are then compared with the outcomes of earlier research on modified Chaplygin gas (MCG) and other Chaplygin gas. We have shown that this model is thermodynamically stable for <span>(xi _0 &lt; 0)</span> in the FRW Universe and studied the validity of the generalised second law of thermodynamics on the apparent and event horizons of the Universe in the FRW Universe dominated by various Chaplygin gas fluids. However, a perfect fluid with <span>(omega _{textrm{eff}}&lt;-frac{1}{3})</span> would produce an acceleration phase but might not produce a feasible dark energy epoch in the early and late stages of the Universe that is consistent with the observational data.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 3","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145165324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comprehensive analysis of the temperature and velocity behaviours in a second-grade fluid flow in a porous medium","authors":"Y M Gifteena Hingis,&nbsp;M Muthtamilselvan,&nbsp;Ikhyun Kim","doi":"10.1007/s12043-025-02961-0","DOIUrl":"10.1007/s12043-025-02961-0","url":null,"abstract":"<div><p>This study investigates the free convective flow of a second-grade incompressible viscous fluid through a vertical duct filled with a porous medium, driven by an oscillating pressure gradient parallel to the channel plates. The flow dynamics are influenced by periodic temperature changes on one of the plates and a significant temperature differential between the plates, which introduces a heat source into the system. Additionally, the effect of duct inclination on the convective flow is explored, as the inclination angle modifies buoyancy forces, thus impacting velocity and temperature profiles. The analysis provides insights into how key parameters, such as the heat source intensity, inclination angle and properties of the second-grade fluid, affect the temperature field, phase angles, velocity profiles and heat transfer rates. A comprehensive visual representation illustrates the effects of amplitude of these factors on the thermal and flow characteristics, highlighting the complex interactions between fluid elasticity, porous media resistance and thermal gradients.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 3","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145164541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative study and shape factor analysis of the EMHD flow on tangent hyperbolic tetrahybrid (hbox {Al}_2hbox {O}_3), Ag, (hbox {TiO}_2) and ZnO nanoparticles over the horizontal and exponentially non-Darcy porous stretching/shrinking cylinder","authors":"P Senbagaraja,&nbsp;Poulomi De","doi":"10.1007/s12043-025-02928-1","DOIUrl":"10.1007/s12043-025-02928-1","url":null,"abstract":"<div><p>The applications of the present findings are extensive and transformative and these findings help in improving heat transfer in thermal industrial systems, facilitating efficient operation of solar collectors, electronic cooling devices, as well as targeting and destroying cancer cells in hyperthermia treatment in the medical field. This study analyses the tangent hyperbolic nanofluid with tetrahybrid nanoparticle that is the combination of <span>(hbox {Al}_2)</span> <span>(hbox {O}_3)</span>, Ag, <span>(hbox {TiO}_2)</span> and ZnO over horizontal and exponentially stretching/shrinking cylinder filled with non-Darcy porous medium. Electromagnetohydrodynamics (EMHD), Arrhenius activation energy, thermal radiation, heat source and chemical reaction were considered. The fundamental equations of non-linear ordinary differential equations (ODEs) were derived from the partial differential equations (PDEs) with similarity variables and fifth-order Runge–Kutta–Fehlberg method with shooting technique was performed. From the model, we obtained increase in temperature profile for magnetic parameter and radiation parameter and increase in concentration profile for activation energy parameter. Shape factor analysis on Nusselt number and Sherwood number was done and compared. Heat and mass transfer rate was investigated by changing the shapes of the nanoparticle on exponential and horizontal cylinder to get good results.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 3","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145163193","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantum correlation of entangled spin-coherent states in non-inertial frames","authors":"Reza Hamzehhofi,&nbsp;Mehrzad Ashrafpour,&nbsp;Davood Afshar","doi":"10.1007/s12043-025-02940-5","DOIUrl":"10.1007/s12043-025-02940-5","url":null,"abstract":"<div><p>This study uses spin coherent states to generate two- and three-partite entangled states. We then investigate the entanglement and correlation of these systems when one component undergoes uniform acceleration. The entanglement of bipartite and tripartite states is quantified using concurrence and 3-tangle, respectively, while the mutual entropy is used to evaluate the system correlation. The findings indicate that the entanglement and correlation decrease as a function of the acceleration parameter. Furthermore, a comparison of entanglement and mutual entropy reveals that the correlation of the bipartite system is predominantly manifested as entanglement. However, the quantum correlation of the tripartite system is of an entanglement type within a certain range of the coherence parameter, but outside this range, it transforms into a classical type.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 3","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145163194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Application of extended residual power series method for time-fractional Zakharov–Kuznetsov equations in ocean-based coastal wave","authors":"Sanjeev Yadav,&nbsp;Ramesh Kumar Vats,&nbsp;Anjali Rao","doi":"10.1007/s12043-025-02947-y","DOIUrl":"10.1007/s12043-025-02947-y","url":null,"abstract":"<div><p>The main aim of this paper is to obtain the approximate series solution of the time-fractional nonlinear Zakharov–Kuznetsov (TFZK) equations using the Laplace residual power series (LRPS) method. LRPS method is a coupling where Laplace transformation is gracefully combined with the residual power series method. One important feature of the LRPS technique is that it uses the concept of limits at infinity, which help us to determine the unknown coefficients of the convergent power series solution. Caputo fractional derivative is used in the formulation of Zakharov–Kuznetsov (ZK) equations. The ZK equations with time-fractional derivative have significant implications in the study of wave dynamics in ocean-based coastal regions, making their approximate solution essential for understanding complex wave phenomena. To validate the effectiveness of the LRPS approach, we analysed two different forms of the TFZK equation. Simultaneously, we visually captured the physical behaviour of the approximate solution using various tables and plots for different fractional orders. Numerical simulation is demonstrated using Maple and Matlab. Comparative analyses were performed with other existing methods, demonstrating the superiority of the LRPS method in solving TFZK equations.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 3","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145163195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}