Results 131 to 140 of about 26,635,104 (298)
Effects of spatial curvature on the f (R) gravity phase space: No inflationary attractor?
, 2019 © 2019 IOP Publishing Ltd Printed in the UK. In this paper we study the effects of spatial curvature of the metric on the phase space of vacuum f (R) gravity.
Oikonomou V., Odintsov S.
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Spherical symmetry in f(R)-gravity
, 2008 Spherical symmetry in f(R)-gravity is discussed in detail considering also the relations to the weak field limit. Exact solutions are obtained for constant Ricci curvature scalar and for Ricci scalar depending on the radial coordinate.
Capozziello, S +2 more
core +1 more source
A Soft Robotic Fish With a Dielectric Elastomer Actuator Body and Negative Stiffness Spine
Advanced Robotics Research, EarlyView.This work introduces a bio‐mimetic soft robotic fish driven by fiber‐reinforced dielectric elastomer actuators integrated as its body. By prestretching this active skin against a flexible spine, a negative stiffness system is created, enabling large‐amplitude bending.
Markus Koenigsdorff +4 more
wiley +1 more source
Investigating $f(R)$ gravity and cosmologies
The f (R) theory of gravity is an extended theory of gravity that is based on general relativity in the simplest case of $f(R) = R$. This theory extends such a function of the Ricci scalar into arbitrary functions that are not necessarily linear, i.e ...
Kalvakota, Vaibhav
core +1 more source
Semi-analytic galaxy formation in f(R)-gravity cosmologies
, 2013 Modifications of the equations of general relativity at large distances offer one possibility to explain the observed properties of our Universe without invoking a cosmological constant. Numerous proposals for such modified gravity cosmologies exist, but
Bianchi D. +3 more
core +1 more source
Efficient and Robust Standing Postures of Quadruped Robots
Advanced Robotics Research, EarlyView.A calibrated static framework estimates load, optimizes torques, and adapts posture so quadruped robots stand efficiently and robustly under external payloads, achieving up to 50% lower torque demand. Inspired by the natural posture adjustments of animals under external loading, this article presents an optimization‐based framework for minimizing joint
Mohamad Kanaan +5 more
wiley +1 more source
Dual‐Mode Gripper With Suction and Shape‐Adaptive Freezing Grasps
Advanced Robotics Research, EarlyView.This study presents a dual‐mode robotic gripper that combines vacuum suction with a shape‐adaptive freezing grasp. The freezing mode uses a compliant rubber membrane, a sprayed water layer, and dry‐ice powder to generate ice‐mediated adhesion while conforming to complex geometries.
Takuma Yanagisawa +4 more
wiley +1 more source
A Deep Dive into f(R) Gravity Theory
, 2011 In this paper we have derived the behavior of deceleration parameter with respect to redshift in context of f(R) gravity in vacuum using Taylor expansion of derivative of action. Here we have obtained that the two first terms in Taylor expansion may describe the late time acceleration which is appeared by SNeIa without need of dark energy and dark ...
Asgari, Solmaz, Saffari, Reza
openaire +2 more sources
Modulation of miR‐23b Wnt/β‐catenin Axis Strengthens Endothelial Barrier Properties
Advanced Science, EarlyView.Early blood‐brain barrier (BBB) disruption contributes to stroke and CNS disease pathology. miR‐23b was identified as a regulator of BBB integrity in brain endothelial cells. Inhibition of miR‐23b enhanced barrier‐associated properties, promoted repair‐related signaling, and reduced BBB leakage in experimental stroke models, supporting further ...
Victor Anthony Martinez +16 more
wiley +1 more source
Cosmological Models in Modified f(R) Gravity Theories
, 2011 La actual expansión acelerada del universo sigue siendo un gran misterio para la física. Varios modelos se han propuesto para su explicación, entre ellos el de la energía oscura, que sin embargo posee problemas tanto de carácter teórico como ...
Guarnizo Trilleras, Alejandro
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