Results 111 to 120 of about 84,386 (305)
Probing dark energy through perfect fluid thermodynamics
, 2020 We demonstrate that the thermodynamics of a perfect fluid describing baryonic matter can, in certain limits, lead to an equation of state similar to that of dark energy. We keep the cosmic fluid equation of state quite general by just demanding that the
Lukes-Gerakopoulos, Georgios
core
AxiomsIn this work, we obtained exact solutions of Einstein’s field equations for plane symmetric cosmological models by assuming that they admit conformal motion.
Ragab M. Gad +2 more
doaj +1 more source
Flexoelectrically Induced Polar Topology in Twisted SrTiO3 Membranes
Advanced Materials, EarlyView.Twisted SrTiO3 bilayers host polar vortices of flexoelectric origin, revealed through combined experiment and theory. By reconstructing polarization from the toroidal moment of strain gradients, the work establishes a 3D chiral state with broken inversion and mirror symmetries.
Isabel Tenreiro +13 more
wiley +1 more source
Boost-invariant motion of relativistic perfect fluid [PDF]
, 1984 Equations of motion of relativistic perfect fluid subject to Bjorken’s boost-invariant conditions are analysed. General relations between the gradient of temperature and the shape of stream lines are derived. The case of pure transverse motion (vanishing
Dyrek, A., Florkowski, Wojciech
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Petrou types D and II perfect-fluid solutions in generalized Kerr-Schild form.
, 1988 Petrov types D and II perfect-fluid solutions are obtained starting from conformally flat perfect-fluid metrics and by using a generalized KerrSchild ansatz. Most of the Petrov type D metrics obtained have the property that the velocity of the fluid does
F. Martín-Pascual +3 more
core +1 more source
Post-Newtonian Expansions for Perfect Fluids [PDF]
Communications in Mathematical Physics, 2009 We prove the existence of a large class of dynamical solutions to the Einstein-Euler equations that have a first post-Newtonian expansion. The results here are based on the elliptic-hyperbolic formulation of the Einstein-Euler equations used in \cite{Oli06}, which contains a singular parameter $\ep = v_T/c$, where $v_T$ is a characteristic velocity ...
openaire +3 more sources
Electrically Readable Lateral Flow Assay Using Organic Transistors for Diagnostic Applications
Advanced Materials, EarlyView.Electrolyte‐gated organic field‐effect transistors (EGOFETs) are integrated with lateral flow (LF) paper fluidics to create a reusable, portable, and low‐cost point‐of‐care (PoC) diagnostic test. The devices are validated for Human Immunoglobulin G detection, achieving high sensitivity (0.1 fm), selectivity, and reproducibility with rapid results in 20–
María Jesús Ortiz‐Aguayo +4 more
wiley +1 more source
Rainich-type Conditions for Perfect Fluid Spacetimes
, 2014 In this worksheet we describe and illustrate a relatively simple set of new Rainich-type conditions on an n-dimensional spacetime which are necessary and sufficient for it to define a perfect fluid solution of the Einstein field equations. Procedures are
Torre, Charles G +3 more
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Mechanically Programmable DNA Hydrogel Microparticles for 3D Cellular Systems
Advanced Materials, EarlyView.DNA hydrogel microparticles are designed to exhibit controllable viscoelasticity and stiffness across three orders of magnitude from 30Pa$30 \,\mathrm{Pa}$ to 6.5kPa$6.5 \,\mathrm{kPa}$. They are uptaken into fibroblast spheroids where they are actively remodeled by cellular forces depending on their mechanical properties.
Tobias Walther +9 more
wiley +1 more source
Perfect Fluid Spacetimes Admitting Almost Riemann Solitons
AxiomsIn this investigation, we examine the geometric character of almost Riemann solitons and gradient almost Riemann solitons in the context of perfect fluid solutions of the Einstein equations that admit a torse-forming vector field ζ.
Mehdi Jafari, Shahroud Azami
doaj +1 more source