Theoretical and Mathematical Physics最新文献_第6页

Solving the missing baryon problem: A review of observational and theoretical advances 解决失踪重子问题：观测和理论进展综述

IF 1.1 4区物理与天体物理

Theoretical and Mathematical Physics Pub Date : 2025-06-25 DOI: 10.1134/S0040577925060017

V. Priyadharshini, S. Vijikumar, V. Bhuvaneshwari

{"title":"Solving the missing baryon problem: A review of observational and theoretical advances","authors":"V. Priyadharshini, S. Vijikumar, V. Bhuvaneshwari","doi":"10.1134/S0040577925060017","DOIUrl":"10.1134/S0040577925060017","url":null,"abstract":" The missing baryon problem represents a longstanding challenge in cosmology, highlighting a discrepancy between the amount of baryonic matter predicted by cosmological models and the amount directly observed in the universe. While observations of the cosmic microwave background and Big Bang nucleosynthesis accurately constrain the baryon density of the early universe, only a fraction of this baryonic matter is accounted for in stars, galaxies, and hot gas within galaxy clusters today. Recent advances suggest that much of the missing baryonic matter resides in the warm–hot intergalactic medium (WHIM), a diffuse, filamentary gas with temperatures of (10^5)–(10^7) K. Detecting the WHIM has been challenging due to its low density and weak emissions. However, breakthroughs in observational techniques, such as X-ray and UV spectroscopy, along with cosmological simulations, have provided compelling evidence for its presence. This review synthesizes the latest theoretical and observational efforts to locate the missing baryons, emphasizing the role of the WHIM, novel detection strategies, and their implications for understanding large-scale cosmic structure and galaxy formation. Future missions promise to refine these findings, bringing us closer to resolving this fundamental issue in astrophysics. ","PeriodicalId":797,"journal":{"name":"Theoretical and Mathematical Physics","volume":"223 3","pages":"879 - 887"},"PeriodicalIF":1.1,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145145194","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}

引用次数: 0

Enhancing microfluidic transport via pulsatile flow: A study of flow regimes and efficiency optimization 通过脉动流增强微流体的传输：流动形式和效率优化的研究

IF 1.1 4区物理与天体物理

Theoretical and Mathematical Physics Pub Date : 2025-06-25 DOI: 10.1134/S0040577925060157

G. Durga Priyadarsini, B. Umesh, G. C. Sankad, G. Murali

{"title":"Enhancing microfluidic transport via pulsatile flow: A study of flow regimes and efficiency optimization","authors":"G. Durga Priyadarsini, B. Umesh, G. C. Sankad, G. Murali","doi":"10.1134/S0040577925060157","DOIUrl":"10.1134/S0040577925060157","url":null,"abstract":" Microfluidic technologies have emerged as transformative diagnostic tools in health care, significantly accelerating diagnostic processes and enhancing patient outcomes. This article explores the principles of fluid dynamics in microfluidic systems, particularly at low Reynolds numbers, and their practical applications. Traditional microfluidic devices often rely on additional hardware for liquid handling, increasing costs, complicating maintenance, and limited accessibility in low-resource settings. To address these challenges, the study introduces a mechanically pulsating heat exchanger utilizing microfluidic technologies, which incorporates internal walls within the flow channel. This innovative design alters the flow patterns of liquid and vapor plugs, significantly improving thermal efficiency in heat pipes. The article highlights the role of flow patterns in preventing blockages and their utility in generating emulsion droplets, blending substances, and separating components through periodic mass flow fluctuations. Furthermore, the advantages of pulsatile flow in microfluidic systems are examined. Unlike steady flows, pulsatile flows offer unique benefits, such as simulating physiological conditions, enhancing cell culture environments, and automating bioassays. These capabilities make pulsatile flows invaluable for advancing biomedical research and diagnostic technologies. However, realizing their full potential requires deeper physics-based insights and further research. This work underscores the promise of microfluidic systems in health care and beyond, paving the way for cost-effective, efficient, and accessible diagnostic solutions. ","PeriodicalId":797,"journal":{"name":"Theoretical and Mathematical Physics","volume":"223 3","pages":"1032 - 1047"},"PeriodicalIF":1.1,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145145141","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}

引用次数: 0

Three-dimensional MHD flow of a radiative Eyring–Powell nanofluid: Exploring Hall effects and heat transfer 辐射Eyring-Powell纳米流体的三维MHD流动：探索霍尔效应和传热

IF 1.1 4区物理与天体物理

Theoretical and Mathematical Physics Pub Date : 2025-06-25 DOI: 10.1134/S0040577925060170

G. Murali, P. Lakshmi, M. Amarnath, J. Venkata Madhu, A. P. Lingaswamy

引用次数: 0

Unitary Ramanujan sum for power system applications 电力系统应用的一元拉马努金和

IF 1.1 4区物理与天体物理

Theoretical and Mathematical Physics Pub Date : 2025-06-25 DOI: 10.1134/S0040577925060108

E. Kiran Babu, Y. Rajasekhara Gowd, G. Satheesh

引用次数: 0

Radiation influence on transient MHD convection over a permeable surface with thermal diffusion 辐射对具有热扩散的可渗透表面瞬态MHD对流的影响

IF 1.1 4区物理与天体物理

Theoretical and Mathematical Physics Pub Date : 2025-06-25 DOI: 10.1134/S0040577925060042

Sk. Nuslin, D. A. Rawoof, P. L. Pallavi, D. Padma, D. Naheed, M. L. Gundagani

引用次数: 0

Magnetohydrodynamic unsteady rotating Casson fluid flow with Hall and ion-slip impacts 具有霍尔和离子滑移冲击的磁流体动力学非定常旋转卡森流体流动

IF 1.1 4区物理与天体物理

Theoretical and Mathematical Physics Pub Date : 2025-06-25 DOI: 10.1134/S0040577925060169

Pudari Chandra Mohan, Y. Suresh Kumar, Anjanna Matta

{"title":"Magnetohydrodynamic unsteady rotating Casson fluid flow with Hall and ion-slip impacts","authors":"Pudari Chandra Mohan, Y. Suresh Kumar, Anjanna Matta","doi":"10.1134/S0040577925060169","DOIUrl":"10.1134/S0040577925060169","url":null,"abstract":" This research explores the influence of Hall ion slip and diffusion thermo effects on the unsteady magnetohydrodynamic (MHD) flow of a viscous, incompressible, electrically conducting, and optically thick radiating Casson fluid through a porous medium in a rotating system. The flow is analyzed under the impact of Joule heating and viscous dissipation, both of which play a crucial role in altering the thermal and hydrodynamic behavior of the fluid. The governing nonlinear equations for velocity, temperature, and concentration are derived and solved using a two-term perturbation technique, subject to physically relevant boundary conditions. The study provides exact solutions to these equations, offering insights into the intricate interplay between key parameters, such as the Hall current, thermal diffusion, porosity, and rotating system’s influence. The variations in velocity, temperature, and concentration profiles with respect to these parameters are illustrated graphically to highlight their effects comprehensively. Furthermore, the skin friction coefficient, the Nusselt number, and the Sherwood number are derived and presented in tabular form, enabling a quantitative assessment of the flow’s thermal and mass transfer characteristics. To validate the proposed solutions, comparisons are made with previously published results, demonstrating excellent agreement and reinforcing the reliability of the analysis. These findings contribute to a deeper understanding of the dynamics of electrically conducting fluids in porous and rotating environments, with potential applications in advanced engineering systems, thermal management, and industrial processes involving MHD flows. ","PeriodicalId":797,"journal":{"name":"Theoretical and Mathematical Physics","volume":"223 3","pages":"1048 - 1069"},"PeriodicalIF":1.1,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145145142","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}

引用次数: 0

Heat transfer analysis of a pineapple leaf fiber nanofluid/MWCNT–water convective flow over a disk 菠萝叶纤维纳米流体/ mwcnt -水在圆盘上对流的传热分析

IF 1.1 4区物理与天体物理

Theoretical and Mathematical Physics Pub Date : 2025-06-25 DOI: 10.1134/S0040577925060121

V. R. Prasad, K. Jyothi, C. Sai Pranathi, K. Reddy

引用次数: 0

A generalized Sylvester equation and discrete Ablowitz–Kaup–Newell–Segur type equations 广义Sylvester方程和离散ablowitz - kap - newwell - segur型方程

IF 1 4区物理与天体物理

Theoretical and Mathematical Physics Pub Date : 2025-05-26 DOI: 10.1134/S004057792505006X

Ya-Nan Hu, Shou-feng Shen, Song-lin Zhao

{"title":"A generalized Sylvester equation and discrete Ablowitz–Kaup–Newell–Segur type equations","authors":"Ya-Nan Hu, Shou-feng Shen, Song-lin Zhao","doi":"10.1134/S004057792505006X","DOIUrl":"10.1134/S004057792505006X","url":null,"abstract":" A generalized Sylvester equation is introduced to revisit the Cauchy matrix schemes of the discrete negative-order Ablowitz–Kaup–Newell–Segur (AKNS) equation and the discrete third-order AKNS equation. Starting from the generalized Sylvester equation, we introduce a master function (boldsymbol{S}^{(i,j)}) that admits a recurrence relation under a constraint relation. By imposing the shifts on matrices (boldsymbol{r}) and (,^mathrm{t}! {boldsymbol{s}}), the shifts of the master function (boldsymbol{S}^{(i,j)}) are derived. By introducing the dependent variables, the above two discrete AKNS equations are constructed as closed forms. For two different choices of the coefficient matrices in the Sylvester equation that preserve the constraint condition, exact solutions in asymmetric and symmetric cases are presented, with one-soliton, two-soliton, and the simplest Jordan-block solutions given explicitly. Continuum limits to the semidiscrete and continuous AKNS-type equations as well as the corresponding exact solutions are also discussed. ","PeriodicalId":797,"journal":{"name":"Theoretical and Mathematical Physics","volume":"223 2","pages":"782 - 809"},"PeriodicalIF":1.0,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144140232","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}

引用次数: 0

Integration of equations of acoustics of inhomogeneous media 非均匀介质声学方程的积分

IF 1 4区物理与天体物理

Theoretical and Mathematical Physics Pub Date : 2025-05-26 DOI: 10.1134/S0040577925050058

O. V. Kaptsov

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Butterfly velocity and chaos suppression in de Sitter space 德西特空间中的蝴蝶速度与混沌抑制

IF 1 4区物理与天体物理

Theoretical and Mathematical Physics Pub Date : 2025-05-26 DOI: 10.1134/S0040577925050101

D. S. Ageev

引用次数: 0