Article
Physics, Nuclear
H. Nazar, Ali H. Alkhaldi, G. Abbas, M. R. Shahzad
Summary: This paper investigates the new definition of complexity factor for irrotational spherical relativistic structures in the Rastall theory of gravity. By studying field equations and observational data, the paper analyzes the physical impacts of material variables and finds the complexity factor using structure scalars. It is emphasized that the vanishing complexity factor condition is crucial for cancelling out energy density inhomogeneity and pressure anisotropy, with solutions provided for interior formation of spherical stellar objects. Additionally, the presence of a nonminimal curvature-matter couple parameter alpha enhances the complexity of the system, with the outcomes potentially reverting back to previous solutions under General Relativity by setting alpha = 0.
INTERNATIONAL JOURNAL OF MODERN PHYSICS A
(2021)
Article
Mathematics
Imre Ferenc Barna, Mihaly Andras Pocsai, Gergely Gabor Barnafoldi
Summary: In this paper, a fluid model with a linear equation of state including the gravitation term is proposed. The spherical symmetric Euler equation and the continuity equations are investigated using a specific self-similar ansatz. The results show that this model is capable of describing physically relevant diffusive and disperse solutions, and the influence of initial conditions on the energy density of the fluid is discussed.
Article
Physics, Multidisciplinary
B. Dayanandan, T. T. Smitha, S. K. Maurya
Summary: This paper presents a new gravitationally decoupled anisotropic solution for the compact star model using the minimal geometric deformation approach. The author employs two different mimic approaches to determine the deformation function and tests the physical viability of the solution through various conditions. The study concludes that the solutions appear viable as far as observational data are concerned.
Article
Physics, Particles & Fields
Abdelghani Errehymy, G. Mustafa, Youssef Khedif, Mohammed Daoud, H. Alrebdi, Abdel-Haleem Abdel-Aty
Summary: This paper presents a model of compact stars described by a new class of exact solutions to the field equations in the context of general relativity. The model is based on a locally anisotropic fluid configuration and is shown to be regular, viable, and stable under the influence generated by the theory parameters. It offers empirical evidence in support of the evolution of realistic stellar configurations.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Mathematics
Mario Garcia-Fernandez, Vamsi Pritham Pingali, Chengjian Yao
Summary: The study gives a complete solution to the existence problem for gravitating vortices, proving results through the continuity method that require satisfaction of a specific stability condition. It is based on previous results and extends the findings to establish solutions for different topological constants.
ADVANCES IN MATHEMATICS
(2021)
Article
Physics, Fluids & Plasmas
Shailendra K. Rathor, Sagar Chakraborty, Samriddhi Sankar Ray
Summary: We investigate the scaling form of appropriate timescales in rotating turbulent flows by analyzing time-dependent correlation functions. We obtain precise estimates of the dynamic exponents associated with these timescales and compare them with the commonly measured equal-time exponents. Theoretical predictions based on the multifractal formalism are validated through extensive numerical simulations of a shell model for rotating flows.
Article
Physics, Multidisciplinary
S. K. Maurya, Ksh Newton Singh, Abdelghani Errehymy
Summary: In this article, an anisotropic solution for compact static spherically symmetric objects in the context of five-dimensional Einstein-Gauss-Bonnet (EGB) theory is investigated. The study focuses on the class of compact stars also known as strange stars. The results show the influence of parameter tuning on the inner geometry and physical properties of the compact stars.
EUROPEAN PHYSICAL JOURNAL PLUS
(2022)
Article
Physics, Multidisciplinary
Berta Martinez-Prat, Ricard Alert, Fanlong Meng, Jordi Ignes-Mullol, Jean-Francois Joanny, Jaume Casademunt, Ramin Golestanian, Francesc Sagues
Summary: Experimental results of active nematic fluid show that kinetic energy spectrum follows theoretical predictions at small and intermediate scales, but is influenced by the 3D oil layer at larger scales, leading to the emergence of a new scaling regime. The study reveals that external dissipation plays a significant role in affecting the spectrum properties.
Article
Multidisciplinary Sciences
S. Rufo, M. A. R. Griffith, Nei Lopes, Mucio A. Continentino
Summary: This work proposes the study of topological models focusing on their anisotropic quantum critical behavior and presents a scaling relation for anisotropic quantum hyperscaling. By introducing a generalized Weyl semimetal model and studying topological surface states, a new scaling relation for critical exponents is proposed, revealing insights into anisotropic quantum hyperscaling.
SCIENTIFIC REPORTS
(2021)
Article
Acoustics
Keith Davey, Hamed Sadeghi, Christian Adams, Rooholamin Darvizeh
Summary: This article introduces the recently developed finite similitude theory and scaling experiment method for vibrational analysis. The study shows that scaled models can accurately represent titanium prototypes and can be used in experiments with different materials.
JOURNAL OF SOUND AND VIBRATION
(2022)
Article
Acoustics
Keith Davey, Hamed Sadeghi, Christian Adams, Rooholamin Darvizeh
Summary: This article introduces a calculus theory based on the concept of space scaling, providing scaled experiment rules for predicting the behavior of full-scale systems, focusing on anisotropic scaling of thin-walled vibrating structures.
JOURNAL OF SOUND AND VIBRATION
(2022)
Article
Physics, Fluids & Plasmas
Ephrem Tesfaye Desta, A. Hillier, Tigistu Haile Eritro
Summary: The study discusses the effect of Braginskii's full viscosity tensor on an infinite non-conducting, gravitating anisotropic plasma in the context of Braginskii's magnetohydrodynamic model, with a focus on stability for parallel and transverse perturbations. Both gravitational and fire-hose instabilities are found, and different viscous terms work in different ways to suppress instability. The results have implications for the study of large scale plasma flow in various astrophysical environments.
PHYSICS OF PLASMAS
(2021)
Article
Physics, Multidisciplinary
F. E. M. Silveira
Summary: In this study, the critical mass of a self-gravitating gas cloud is determined, indicating the collapse of the gas above this mass. The analysis departs from a non-homogeneous equilibrium density and defines a time scale based on the adiabatic index. The study presents equilibrium profiles of the density, gravitational field, and potential at the point of marginal instability.
Article
Astronomy & Astrophysics
Alfredo Herrera-Aguilar, Daniel F. Higuita-Borja, Julio A. Mendez-Zavaleta
Summary: A new family of exact black hole configurations is presented as a solution to a generalized Einstein-Maxwell-Dilaton setup, with analysis on the thermodynamics of anisotropic field configurations and interesting limits linking it to well-known solutions. The existence of a nontrivial scalar field is found to be a result of breaking the spacetime isotropic scaling symmetry, providing insights into the emergence of the dilaton field.
Article
Physics, Fluids & Plasmas
S. A. Khrapak, A. G. Khrapak
Summary: The study shows that the reduced transport coefficients of Lennard-Jones fluids along isotherms exhibit quasi-universal scaling on the density divided by its value at the freezing point. This scaling is closely related to the density scaling of transport coefficients of hard-sphere fluids. Additionally, the Stokes-Einstein relation without the hydrodynamic diameter is valid in the dense fluid regime, with the lower density boundary of its validity serving as a practical demarcation line between gaslike and liquidlike regimes.