Pramana最新文献

{"title":"A new framework for the relativistic transformations of thermodynamic variables using momentum as the thermodynamic potential","authors":"Parag M Ahmedabadi","doi":"10.1007/s12043-025-02913-8","DOIUrl":"10.1007/s12043-025-02913-8","url":null,"abstract":"<div><p>A generalised relativistic transformation for thermodynamic variables is derived in this study using the basic energy–momentum relationship of special relativity. We posit that momentum undergoes changes akin to a time coordinate and treat it as a thermodynamic potential analogous to energy potential. Additionally, we presume that momentum transforms similarly to a time coordinate. We analyse two mutually exclusive conditions to simplify generalised transformations. In one condition, the transformations are as follows: volume <span>( V = gamma V' )</span>, internal energy <span>( U = gamma U' )</span>, temperature <span>( T = gamma T' )</span> and pressure <span>( P = P' )</span>, where <span>( gamma )</span> represents the Lorentz factor. The primed variables correspond to the moving frame, while the unprimed variables correspond to the stationary frame. The other condition yields <span>( V = V'/gamma )</span>, <span>( U = U'/gamma )</span>, <span>( T = T'/gamma )</span>, <span>( P = P' )</span>. Since the first law of thermodynamics is an energy conservation statement and Maxwell and other thermodynamic relationships are mathematical constructs based on the first law, it is expected that such relationships should remain invariant in all frames for relativistic thermodynamic transformations. We demonstrate that the ideal gas equation, Maxwell relationships and other thermodynamic relationships (for example, <span>( (partial U/partial V)_T = -P + T(partial P/partial T)_V )</span>) remain invariant under these two sets of transformations. Furthermore, we show that, although the ideal gas equation and Maxwell relationships remain invariant for many transformations reported earlier, <span>( (partial U/partial V)_T = -P + T(partial P/partial T)_V )</span> remains invariant only for the Sutcliffe transformation (<span>( V = V'/gamma )</span>, <span>( U = gamma U' )</span>, <span>( T = gamma T' )</span>, <span>( P = gamma ^2 P' )</span>). We establish that when <span>( U )</span>, heat <span>( Q )</span> and work <span>( W )</span> transform similarly, all thermodynamic relationships remain invariant, and such a formalism is mathematically consistent.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 2","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143840400","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 cosmic evolution through the new agegraphic dark energy model in (f(Q, {mathbb {T}})) gravity","authors":"M Sharif,&nbsp;Eman M Moneer,&nbsp;Iqra Ibrar,&nbsp;Euaggelos E Zotos","doi":"10.1007/s12043-025-02906-7","DOIUrl":"10.1007/s12043-025-02906-7","url":null,"abstract":"<div><p>This study explores the reconstruction method within the framework of <span>(f(Q, {mathbb {T}}))</span> gravity by utilising the new agegraphic dark energy (A<span>(mathbb {DE)})</span> model, where <i>Q</i> represents non-metricity and <span>({mathbb {T}})</span> is the trace of the energy–momentum tensor. The <span>(f(Q, {mathbb {T}}))</span> new A<span>({{mathbb {D}}}{{mathbb {E}}})</span> model is developed through a non-interacting correspondence approach. This theoretical model is then examined in the context of a flat Friedmann–Robertson–Walker (FRW) cosmological framework, which is defined by a power-law scale factor and a pressureless perfect fluid. This modified gravity framework effectively captures different stages of the evolution of the Universe. The reconstructed model is employed to calculate the equation of state parameter, phase planes and the squared speed of sound. The equation of state parameter indicates a quintessence phase, the <span>(omega _{mathbb{D}mathbb{E}})</span>–<span>(omega '_{mathbb{D}mathbb{E}})</span> plane reveals the freezing region and the <span>(textbf{r})</span>–<span>(textbf{s})</span> phase plane corresponds to the Chaplygin gas model. Additionally, the squared sound speed parameter suggests instability in the current cosmic evolution. Our study demonstrates that <span>(f(Q, {mathbb {T}}))</span> gravity provides an accurate and comprehensive framework for explaining cosmic expansion, effectively encompassing the dynamics across all stages of the Universe’s evolution.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 2","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143835730","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":"Nuclear level density studies using deep neural network techniques","authors":"K Jyothish,&nbsp;V Parvathi,&nbsp;A K Rhine Kumar","doi":"10.1007/s12043-025-02907-6","DOIUrl":"10.1007/s12043-025-02907-6","url":null,"abstract":"<div><p>This study employs a deep neural network (DNN) model to investigate nuclear level density (NLD) using experimental data obtained using the Oslo method. The work focusses on lanthanide nuclei and period-5 nuclei; the DNN model predictions are compared with experimental results. Also, we compare our results with the HFB<span>(+)</span>Cmb (Hartree–Fock–Bogoliubov plus combinatorial) model results retrieved from the RIPL3 data. The DNN model demonstrates higher performance, yielding root mean square (RMS) error values of 0.098 <span>(textrm{MeV}^{-1})</span> for lanthanides and 0.101 <span>(hbox {MeV}^{-1})</span> for period-5 nuclei across a comprehensive spectrum of excitation energies. The observed nuclear level densities at very low excitation energies display anomalous behaviour that may be attributed to the nuclear pairing and shell corrections. These phenomena become less pronounced at higher excitation energies, leading to a more uniform level density trend. Even–even nuclei experience significant effects from pairing at lower excitation energies, changing the level density pattern. The present study predicts NLD using the DNN model for selected isotopes where experimental data are unavailable.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 2","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143821919","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":"Ramsey theory of the phase transitions of the second order","authors":"Edward Bormashenko","doi":"10.1007/s12043-025-02911-w","DOIUrl":"10.1007/s12043-025-02911-w","url":null,"abstract":"<div><p>The Ramsey theory-based approach to the phase transitions of the second order is suggested. The phase transitions of the second order are seen as the switching of physical interactions<span>(/)</span>chemical bonds between the entities forming the primitive cell of the material. Such a switching is typical for phase change materials. The phase transition of the second order takes place if the energy of the primitive cell is kept constant by changing the spatial order of the chemical bonds. The breaking of the initial symmetry of the cell accompanies the switching of interactions between the entities forming the primitive cell. The order parameter<span>(/)</span>the degree of ordering characterising the ordering within the primitive cell is re-defined. The introduced degree of ordering quantifies the ordering of links<span>(/)</span>interactions<span>(/)</span>chemical bonds between entities constituting the 2D lattice, whereas, the classical ‘Landau degree of order’ quantifies the symmetry breaking under variation in spatial locations of these entities. The suggested approach is generalised easily for 3D primitive cells. The thermal capacity of the non-symmetrical phase is larger than that of the symmetrical phase. For the primitive cells consisting of six interacting entities, the Ramsey theory predicts the inevitable appearance of unstable monochromatic triangles, when the links correspond to attraction or repulsion interactions. The situation becomes different for the primitive cells of five interacting entities.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 2","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143821920","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":"Correction: Numerical study of unsteady reactive third-grade fluid flow in a microchannel through a porous medium subject to exothermic reaction","authors":"Idrees Khan,&nbsp;Tiri Chinyoka,&nbsp;Rozli Zulkifli,&nbsp;Emad A A Ismail,&nbsp;Fuad A Awwad,&nbsp;Ahmed M Hassan,&nbsp;Oluwole D Makinde,&nbsp;Zubair Ahmad","doi":"10.1007/s12043-025-02905-8","DOIUrl":"10.1007/s12043-025-02905-8","url":null,"abstract":"","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 2","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143821939","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":"Localised waves and dynamical behaviours of analytical solutions to ((3+1))-dimensional YTSF model in mathematical physics","authors":"Yajun Du,&nbsp;Jing Pang","doi":"10.1007/s12043-025-02902-x","DOIUrl":"10.1007/s12043-025-02902-x","url":null,"abstract":"<div><p>This article focusses on the <span>((3+1))</span>-dimensional Yu–Toda–Sassa–Fukuyama (YTSF) model, which is a type of physical model with complex and nonlinear characteristics describing wave propagation in a medium. By using the technique of generalised exponential rational function (GERF), different types of analytical solutions are obtained successfully, including exponential rational solutions, hyperbolic solutions and trigonometric solutions. Subsequently, their dynamic behaviours and temporal-spatial evolutions are investigated through the visualisation of partial solutions. In addition, we discuss the significance of these findings to comprehend nonlinear wave phenomena and outline the future research directions.\u0000</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 2","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143821936","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":"Thermal analysis of the bio-convective magnetised retardation-type nanofluid flow over a bidirectional sinusoidal moving surface having radiative effects","authors":"Ahmed S Sowayan,&nbsp;Samaira Aziz,&nbsp;Sami Ullah Khan,&nbsp;Nadia Imtiaz,&nbsp; Adnan,&nbsp;Arshad Riaz,&nbsp;Hakim Al Garalleh","doi":"10.1007/s12043-025-02908-5","DOIUrl":"10.1007/s12043-025-02908-5","url":null,"abstract":"<div><p>The nonlinear unsteady flows restricted by moving surfaces have gained particular significance in numerous technological, engineering, industrial, mechanical and biological processes. The flow caused by oscillatory stretched surfaces has attracted particular attention due to its fascinating properties, such as in fluidic oscillators, oscillating jets, oscillation problems, etc. Nanofluids have recently gained much attention due to their potential in numerous applications across various industries. The primary use of the nanomaterials is to increase the effectiveness of heat transfer in various systems. Due to the importance of biomaterial’s in different industrial, technological and engineering systems, the process of bioconvection in nanomaterials has attained reputation in recent years. To lead this exploration, an unsteady bio-convective flow of Oldroyd-B nanomaterial across a bi-directional oscillatory stretched surface is investigated here. Heat generation and thermic radiation have been employed to inspect heat transfer attributes. Furthermore, the effects of magnetic force, chemical reaction and activation energy were employed for the whole analysis. Apposite makeovers were used to convert the deduced nonlinear system to non-dimensional expressions. To yield the series solution, an analytic procedure, namely the homotopy analysis technique (HAM) was adopted. Various graphs were plotted to deliberate the effects of the associated variables on concentration, micro-organism, velocities and temperature profiles. Numeric data were organised in different tables to discuss the importance of different variables on the motile density, local Nusselt and local Sherwood numbers. It has been observed that bidirectional velocities display opposite trends for relaxation and retardation variables. It has further been perceived that amplitudes of velocities periodically decelerate for increase in Hartman number. Greater estimations of heat generation, Brownian motion, thermophoresis and thermic radiation effectively improve the temperature within the nanofluid whereas it diminishes by varying the Prandtl number. Concentration profile declined with Schmidt number, reaction rate and temperature difference variables, while opposite scenario occurred for thermophoresis and activation energy parameters. Moreover, distribution of micro-organisms’ increases for Hartmann number but drops because of greater estimates of the micro-organisms concentration difference, bio-convective Peclet and Lewis numbers.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 2","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143821938","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":"Research on stochastic resonance method in fractional-order tristable systems","authors":"Qiang Ma,&nbsp;Ran Peng,&nbsp;Zhichong Wang,&nbsp;Kai Yang","doi":"10.1007/s12043-025-02901-y","DOIUrl":"10.1007/s12043-025-02901-y","url":null,"abstract":"<div><p>We introduce an innovative approach to fractional-order tristable stochastic resonance (SR), utilising the advantages of temporal memory and spatial correlation inherent in fractional-order systems while harnessing the non-saturating properties of tristable SR mechanisms. First, we derived the fractional-order tristable Langevin equation and studied the SR phenomenon within this system across key parameters, such as the fractional-order <i>α</i>, system parameters and external periodic force, within the <i>α</i> range of (0,2]. We identified the optimal resonance region through this analysis. Second, to achieve adaptive fractional-order SR and effectively handle high-frequency and experimental signals, we introduced a standard scale transformation method along with the butterfly optimisation algorithm. Finally, through verification with simulation signals, laboratory data and experimental data from the outer race fault of an aircraft engine’s intermediate shaft bearing, we demonstrated that our proposed method could efficiently extract weak fault characteristic signals from environments with strong noise. Comparative analysis with traditional tristable SR methods and the empirical mode decomposition algorithm showed that signals extracted using our method exhibited larger characteristic frequency amplitudes and higher signal-to-noise ratios (SNR).</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 2","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143821917","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":"Confinement impacts of magnetic field on beryllium atom, ions and isoelectronic ions embedded in various plasma environments","authors":"Salah Doma,&nbsp;Gamal Roston,&nbsp;Mostafa Ahmed","doi":"10.1007/s12043-025-02899-3","DOIUrl":"10.1007/s12043-025-02899-3","url":null,"abstract":"<div><p>Using the variational Monte Carlo method, a first-time investigation is made for the beryllium atom, ions and isoelectronic ions within three plasma environments confined by an external homogeneous magnetic field. The study focusses on the excited singlet and triplet states included in this work, which are the low-lying excited states (1<i>s</i>²2<i>s</i>2<i>p</i>, 1<i>s</i>²2<i>s</i>3<i>s</i> and 1<i>s</i>²2<i>s</i>3<i>p</i>) and the core excited states (1<i>s</i>2<i>s</i>²3<i>s</i> and 1<i>s</i>2<i>s</i>3<i>s</i>²), utilising plasma potentials, such as the screened Coulomb (SCP), exponential cosine screened Coulomb (ECSCP) and Hulthén potentials. Energy eigenvalues are determined using appropriate trial wave functions, which account for electron–electron repulsion and spin parts to adhere to the Pauli exclusion principle. Moreover, two effective factors related to the wave function of the magnetic field and the ECSCP model are considered. The results reveal an intriguing relative ordering for the lithium atom using the three plasma models, with many of the findings being novel contributions yet to be explored.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 2","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143821918","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":"Multiple regression analysis of the Blasius and Sakiadis flow of the power-law nanofluid over a moving thin needle","authors":"Palani Sathya,&nbsp;Padigepati Naveen,&nbsp;Kuppalapalle Vajravelu","doi":"10.1007/s12043-025-02903-w","DOIUrl":"10.1007/s12043-025-02903-w","url":null,"abstract":"<div><p>Fluid flow over a thin moving needle surrounded by a nanofluid has recently gained attention due to its application in science and technology. Hence, the current investigation aims to analyse a power-law nanofluid flow along a thin needle and make a comparative analysis with Blasius and Sakiadis flow problems. The Buongiorno nanofluid model is used to study the influences of thermophoresis and Brownian motion. Using a Bvp4c method, the dimensionless governing equations of the model are solved. The findings indicate that the power-law index and the needle thickness reduce the velocity field in the Blasius flow, but quite the opposite trend is observed in the Sakiadis flow. In the Sakiadis flow, the temperature and the concentration fields dominate over the Blasius flow. In addition, regression analysis is employed to acquire deeper insight into the engineering quantities. The thermal transmission rate increased in the Sakiadis flow compared to that in the Blasius flow with an increase in the Brownian motion parameter. The study outcomes will help us understand the theoretical concepts behind applications, such as hot wire anemometers, targeted drug delivery, cancer treatment, micro-cooling systems and medical equipments such as dialysis machines, biopsy, infusion pumps, medical implant design.\u0000</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 2","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143778025","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}