Pramana最新文献

{"title":"Heat and mass transfer analysis for thin film lubricated flow of microbe-infused viscoelastic nanofluid","authors":"Manzoor Ahmad,&nbsp;Mudassir Arif,&nbsp;Sami Ullah Khan,&nbsp; Adnan,&nbsp;Arshad Riaz,&nbsp;Ahmed S Sowayan","doi":"10.1007/s12043-025-02892-w","DOIUrl":"10.1007/s12043-025-02892-w","url":null,"abstract":"<div><p>Non-Newtonian materials are suggested as lubricants to maintain the high performances of various mechanical and industrial processes. Viscoelastic fluids as lubricants improve the mechanical and thermal processes. The objective of the current analysis is to highlight the significance of power-law viscoelastic lubricant in the flow of Walters B nanofluid in a moving frame. The role of higher-order slip as an interfacial constraint is studied for the lubrication phenomenon. Walters B nanofluid flow is a stagnation point flow. The Buongiorno nanofluid model is used to study the Brownian motion and thermophoresis size-dependent effects. The analysis is further updated by incorporating the bioconvective phenomenon with suspension of microbes. After modelling the problem successfully, it is shown that problem involved higher-order velocity slip conditions for which numerical computations cannot be performed. In order to treat such problems, an updated semi-analytical scheme called the hybrid homotopy analysis method (HHAM) is employed. Key focus is on the physical aspect of parameters. Current results have applications in polymers, lubrications, thermal systems, chemical processes, extrusion systems, etc.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 1","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143521644","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":"Lump wave, breather wave and other abundant wave solutions to the (2 + 1)-dimensional Sawada–Kotera–Kadomtsev Petviashvili equation of fluid mechanics","authors":"Kang-Jia Wang,&nbsp;Hong-Wei Zhu,&nbsp;Feng Shi,&nbsp;Xiao-Lian Liu,&nbsp;Guo-Dong Wang,&nbsp;Geng Li","doi":"10.1007/s12043-024-02884-2","DOIUrl":"10.1007/s12043-024-02884-2","url":null,"abstract":"<div><p>The (2 + 1)-dimensional Sawada–Kotera–Kadomtsev Petviashvili equation (SKKPe) is explored in this work. Wielding the Hopf–Cole transform, its Hirota bilinear form is developed. Then, the lump wave solutions of the bright-type and dark-type, and the breather wave solutions of the sin–cosh type are extracted by applying the Hirota bilinear method with symbolic computation by taking different test functions. Additionally, abundant travelling wave solutions like the bright wave, periodic wave and singular wave solutions are investigated by employing three effective approaches, namely the extend Wang’s direct mapping method II (EWDMM), Bernoulli sub-equation function method (BSEFM) and Kudryashov method (KM). The nonlinear physical characteristics of the attained solutions are displayed graphically using the 3D and 2D plots. To the best of the author's knowledge, the results presented in the article are entirely new and have not been presented elsewhere, which can augment the exact solutions of the considered equation and allow us to study its nonlinear dynamics better.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 1","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143496721","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":"Enhanced UV and IR filtering with PMMA(/)perylene-coated FTO glass for energy-efficient luminescent solar concentrator windows","authors":"S M El-Bashir,&nbsp;W A Almotery,&nbsp;A M Aldhafiri,&nbsp;A M El-Naggar","doi":"10.1007/s12043-024-02889-x","DOIUrl":"10.1007/s12043-024-02889-x","url":null,"abstract":"<p>Luminescent solar concentrator (LSC) windows have been made by the solvent casting of polymethyl methacrylate<span>(/)</span>chloroform solutions doped with different concentrations of perylene yellow dyestuffs (KREMER 94700). The effect of dye concentration on the structure and spectral photophysical properties was studied using field emission scanning electron microscope (FE-SEM), energy-disperse analysis X-ray (EDAX), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, optical absorption, fluorescence spectroscopy and chromaticity diagram (CIE 1931). The fluorescence intensity was the highest when the film has 5 × 10⁻³ wt% doping concentration. This film showed the best long-pass optical filter properties in the 200–535 nm band. In addition, it has high transmittance (∑75%), which is considered promising in ultraviolet (UV) protective window applications. Another important application is establishing infrared (IR) filtering windows based on fluorine-doped tin oxide (FTO) glass spin-coated with the proposed LSC windows. The optical properties of these spectrally selective LSC windows were optimised to significantly reduce harmful solar radiation and enhance energy efficiency for building-integrated photovoltaics, aligning with Saudi Arabia's Vision 2030 goals for sustainable urban development and renewable energy integration.</p>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 1","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143455534","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":"Viscous damping of r-modes and emission of gravitational waves","authors":"Debasis Atta,&nbsp;D N Basu","doi":"10.1007/s12043-025-02897-5","DOIUrl":"10.1007/s12043-025-02897-5","url":null,"abstract":"<div><p>The Rossby mode (r-mode) perturbation in pulsars as a steady gravitational wave source has been explored. The effect of a rigid crust on viscous damping and dissipation rate in the boundary layer between the fluid core and the crust has been studied. The intensity of the emitted GWs in terms of the strain tensor amplitude has been estimated with the approximation of slow rotation using equation of state derived from the APR and Skyrme effective interactions with Brussels–Montreal parameter sets. The core of the neutron star has been considered to be <span>(beta )</span>-equilibrated nuclear matter containing neutrons, protons, electrons and muons, surrounded by a solid crust. Calculations have been made for critical frequencies, time evolution and rate of change of the spin frequencies across a broad spectrum of pulsar masses.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 1","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s12043-025-02897-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143446616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Significance of waste discharge concentration on the fluid flow over a squeezing porous slider: solution by improved residual power series method","authors":"M C Jayaprakash,&nbsp;T Ramachandran,&nbsp;Ambati Vijay Kumar,&nbsp;Vikas Kaushik,&nbsp;Sanjeev Kumar Joshi,&nbsp;A S Siddesh,&nbsp;Nehad Ali Shah,&nbsp;J Rekha","doi":"10.1007/s12043-024-02874-4","DOIUrl":"10.1007/s12043-024-02874-4","url":null,"abstract":"<div><p>The current analysis focusses on the three-dimensional viscous flow caused by an expanding or contracting porous slider under the impact of heat source<span>(/)</span>sink, magnetic field and waste discharge concentration. The amount of fluid injected to levitate the slider is not constant; rather, it varies over time based on the slider's location at any given moment. The fluid flow between the ground and the slider is represented by the unsteady nonlinear equations of motion, which are converted into ordinary differential equations by employing the apt similarity transformations. These simplified equations are solved by applying the hybrid residual power series method (HRPSM). Using graphical representations, the physical behaviour of significant parameters is investigated. Tabular data are used to compare the hybrid residual power series method and the numerical scheme to check the convergence and accuracy of the hybrid residual power series method. A rise in the magnetic parameter results in a very modest rise in the fluid's longitudinal velocity in the regions closest to the upper or lower plates and a clear drop in the liquid's longitudinal velocity in the centre region. An increase in pollutant external-source parameter increases the amount of pollutants introduced into the fluid system.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 1","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s12043-024-02874-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143446617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Projective exponential anti-synchronisation of space–time discrete Lur’e oscillator networks with uncertain Markov jumps","authors":"Shaobin Rao,&nbsp;Tianwei Zhang","doi":"10.1007/s12043-025-02891-x","DOIUrl":"10.1007/s12043-025-02891-x","url":null,"abstract":"<div><p>This paper investigates global projective anti-synchronisation in the mean-square sense in the asymptotic and exponential schemes of space–time discrete Markovian Lur’e dynamical networks with uncertain transition probabilities and Dirichlet boundary values. The findings of this study are noteworthy with regard to global projective asymptotic and exponential anti-synchronisation in the mean-square sense for the proposed discrete Markovian networks. The networks incorporate the Lyapunov–Krasovskii functional, which includes a double sum representing the delay-dependent components. Furthermore, the findings of this study indicate that the global projective asymptotic and exponential anti-synchronisation of space–time discrete Markovian Lur’e dynamical networks with uncertain transition probabilities can be achieved through the design of small diffusion intensities. It was unexpected to discover that the uncertain transition probabilities have no influence on the conditions that guarantee the global projective asymptotic and exponential anti-synchronisation of the networks. This paper presents a framework for exploring the issues of global projective asymptotic or exponential anti-synchronisation for space–time discrete Markovian networks, with the objective of identifying potential applications in a range of contexts. In conclusion, an illustrative example is provided to demonstrate the efficacy of the aforementioned method.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 1","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s12043-025-02891-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143446618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermomagnetic peristaltic Casson flow in a microchannel containing a Darcy–Brinkman porous medium under the influence of oscillatory, thermal radiation, slip and heat source effects","authors":"G Shankar,&nbsp;P Deepalakshmi,&nbsp;E P Siva,&nbsp;D Tripathi,&nbsp;O Anwar Bég","doi":"10.1007/s12043-024-02869-1","DOIUrl":"10.1007/s12043-024-02869-1","url":null,"abstract":"<div><p>The objective of this article is to study mathematically the magnetohydrodynamic (MHD) unsteady non-Newtonian oscillatory blood flow and heat transfer in microchannels containing a Darcy–Brinkman porous medium. The Casson fluid model is deployed. Additionally, the effects of heat source, nonlinear thermal radiation and Hall current are included. Convective heating and slip at the internal boundaries of the microchannel are also examined. Utilising a set of non-dimensional variables, the governing partial differential equations and associated boundary conditions are transformed into a non-dimensional form. By solving the transformed model, exact solutions are obtained. Graphical representations depict the influence of different physical characteristics on the velocity and temperature patterns. In addition, this study incorporated a parametric analysis to demonstrate the impacts of key parameters on Nusselt number and wall shear stress. Increased values of thermal radiation and Casson rheological parameters produce intensified velocity fields. Blood flow is also controlled by modulating the intensity of the external magnetic field and the regulation of the blood temperature is achieved by modifying its thermal conductivity. With an increment in thermal Biot number (<i>Bh</i>) (stronger convective heating at the microchannel walls) there is a uniform increase in temperatures. With the elevation in the Hall parameter, more complex streamline patterns are generated and there is an increase in the magnitude of trapped boluses. An increment in Grashof number (<i>Gr</i>), i.e. stronger thermal buoyancy force, accelerates the flow. Elevation in the Nusselt number is produced with a stronger heat source (<i>S</i>). With greater frequency (<i>ω</i>), the blood flow is more strongly modified by periodic fluctuations in the driving pressure and this produces an elevated amplitude of velocity oscillations, thereby increasing the average velocity of the blood. Increasing slip (<span>(gamma ))</span> generates significant flow deceleration in the microchannel. This work, which focusses on the thermal radiation in the blood flow, will significantly influence therapeutic strategies for hyperthermia. Specifically, the analysis provides a good foundation for more sophisticated computational fluid dynamics (CFD) studies and will enhance our understanding and management of blood flow and heat transfer in, for example, arterial hemodynamics.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 1","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143446581","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":"Influence of Cu content on the fractal and multifractal properties of Zn–Mg–Cu composites","authors":"Maryam Gholizadeh Arashti","doi":"10.1007/s12043-024-02885-1","DOIUrl":"10.1007/s12043-024-02885-1","url":null,"abstract":"<div><p>In this work, the morphology and fractal properties of Zn–Mg and Zn–Mg–Cu nanocomposites were investigated. Zn–Mg–Cu nanocomposites with 2, 3 and 4% by weight of Cu were prepared by electrochemical method on FTO glass substrate and compared with Zn–Mg nanocomposite. The surface properties of the nanocomposites were studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM). SEM images confirm that the morphology and grain size depend on the amount of Cu doping. The grain size decreases with increasing Cu concentration. Statistical analysis based on 3D AFM images showed that surface roughness (<i>S</i>_q) and fractal dimension (<i>D</i>_f) decreased with increasing Cu concentration. <i>D</i>_f obtained using the log(count) vs. log(box size) curve showed that <i>D</i>_f is independent of scan size and pixel resolution. The <i>D</i>_f values of ZM3, ZM3C2, ZM3C3 and ZM3C4 were calculated to be 2.48, 2.44, 2.36 and 2.30, respectively. It can be concluded that the lacunarity coefficient <i>β</i> of all the nanocomposites has a high degree of surface microstructure homogeneity with <i>β</i> &lt; 0.07. Multifractal behaviour was observed for all nanocomposites, with the multifractal degree of Zn–Mg–Cu nanocomposites being reduced compared to that of Zn–Mg nanocomposites.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 1","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s12043-024-02885-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143446512","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Negative frequencies in the scattering properties of parity–time symmetry and anti-parity–time symmetry","authors":"Stéphane Boris Tabeu,&nbsp;Fernande Fotsa-Ngaffo,&nbsp;Aurélien Kenfack-Jiotsa","doi":"10.1007/s12043-024-02872-6","DOIUrl":"10.1007/s12043-024-02872-6","url":null,"abstract":"<div><p>We present the scattering properties of parity–time (PT)-symmetric and anti-parity–time (APT)-symmetric systems embedded in a new electronic waveguide. The set-up is built around imaginary resistors and positive or negative other components. These combinations give rise to a real spectrum in breakable and unbreakable PT symmetries. When it exists, the transition marks the passage from real to complex eigenvalues whereas in the APT symmetry, the eigenvalues pass from pure imaginary to complex eigenvalues. The frequencies of cells in PT-symmetric configurations must have the same sign whereas in APT-symmetric configurations, the frequencies must have opposite signs. The electrical line presented can drive negative frequencies and gives the possibility to demonstrate the existence of a mirror behaviour in scattering properties of the PT symmetry. We derive the condition of appearance of the coherent perfect absorber and laser, unidirectional invisibility from one or both sides of the system. In APT symmetry, only the coherent perfect absorber exists in the two configurations of waveguides used. The respect of the law of conservation depends on the nature of the eigenspectrum peculiar to each type of the dimer.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 1","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143446428","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":"Lie symmetry reductions and exact solutions of Kadomtsev–Petviashvili equation","authors":"Anukriti,&nbsp;Dig Vijay Tanwar","doi":"10.1007/s12043-024-02887-z","DOIUrl":"10.1007/s12043-024-02887-z","url":null,"abstract":"<div><p>This work intents to obtain symmetry reductions and exact solutions of Kadomtsev–Petviashvili (KP) equation, which describes propagation of long waves on the surface of shallow water. The Lie symmetry method under one-parameter transformation is used to ensure invariance and derive infinitesimal generators. These generators provide similarity variables, which is directed to symmetry reductions of the test equation. This process of reductions recasts test equation into ordinary differential equations (ODEs). These ODEs have finally been solved under various constraints and as a result, exact solutions consisting of arbitrary functions and several arbitrary constants are produced. The solutions are novel and have not yet been published. Due to the existence of arbitrary functions <span>(f_1(t))</span>, <span>(f_2(t))</span>, <span>(f_3(t))</span> and constants, these solutions present a more generalised form than the existing results and give a wide range of possibilities for the interpretation of various physical phenomena. The physical importance of these solutions is demonstrated by numerical simulation revealing a rich variety of soliton structures including line soliton, doubly soliton, multisoliton, solitons on parabolic surface, soliton fission and annihilation behaviour.\u0000</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 1","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143446513","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}