Results 111 to 120 of about 1,984,506 (249)
Dark energy and modified gravity [PDF]
, 2010 Explanations of the late-time cosmic acceleration within the framework of general relativity are plagued by difficulties. General relativistic models are mostly based on a dark energy field with fine-tuned, unnatural properties. There is a great variety of models, but all share one feature in common -- an inability to account for the gravitational ...
Durrer, Ruth, Maartens, Roy
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Autonomous Folding of Soft Matter From Living Polymers
Advanced Materials, EarlyView.Origami structures are endowed with “living” polymer creases that grow, remodel, and stiffen in response to nutrient solutions. This post‐fabrication growth enables autonomous folding, iterative regrowth, and mechanical tuning involving origami assemblies, such as cranes, Miura‐ori tessellations, rigid and non‐rigid square‐twist patterns, establishing ...
Jiahe Huang +6 more
wiley +1 more source
A viable model for modified gravity [PDF]
Astrophysics and Space Science, 2014 We propose a model for modified gravity that meets the conditions of viability. The model has stable constant curvature solution and for an special case contains flat space time solution. The model also leads to matter stability under small perturbations of scalar curvature.
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Modified teleparallel theories of gravity [PDF]
, 2018 Teleparallel gravity is an alternative formulation of gravity which has the same field equations as General Relativity (GR), therefore, it is also known as the Teleparallel equivalent of General Relativity (TEGR).
Bahamonde, Sebastian
core +1 more source
Advanced Materials, EarlyView.Spatiotemporal control over cell behavior within bioprinted constructs remains a key challenge in biofabrication. Volumetric bioprinting using multi‐wavelength light sources permits to activate light‐sensitive intracellular proteins as well as optogenetic gene and protein expression circuits in bioprinted cells, in addition to enabling fast printing of
Davide Ribezzi +14 more
wiley +1 more source
Modified gravity black holes and their observable shadows [PDF]
, 2015 The shadows cast by non-rotating and rotating modified gravity black holes are determined by the two parameters mass $$M$$ and angular momentum $$J=Ma$$. The sizes of the shadows cast by the spherically symmetric static modified gravity–Schwarzschild and
J. W. Moffat
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Fast Hydrogel Micro‐Actuators Driven by Electric Fields
Advanced Materials, EarlyView.We report the fabrication of chemically programmable electroactuating microstructures through the first integration of two‐photon polymerization with electrically actuated gelatin methacrylate‐based hydrogels. By tailoring the charge of the polymer network, we demonstrate programmable polarity‐dependent bending, enabling microstructures that ...
Annaël Sort‐Montenegro +6 more
wiley +1 more source
COSMIC ACCELERATION AND MODIFIED GRAVITY
International Journal of Modern Physics D, 2007 I briefly discuss some attempts to construct a consistent modification to general relativity (GR) that might explain the observed late-time acceleration of the Universe and provide an alternative to dark energy. I describe the issues facing extensions to GR, illustrate these with a specific example, and discuss the resulting observational and ...
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Stellar oscillations in modified gravity [PDF]
Physical Review D, 2013 Starting from the equations of modified gravity hydrodynamics, we derive the equ tions of motion governing linear, adiabatic, radial perturbations of stars in scalar-tensor theories. There are two new features: first, the eigenvalue equation for the period of stellar oscillations is modified such that the eigenfrequencies are always larger than ...
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Advanced Materials, EarlyView.Water harvesting, radiative cooling, and interfacial solar evaporation are fundamentally governed by coupled heat, mass, and light transport processes. These processes are mediated by pore architecture, including pore size, connectivity, and hierarchical organization.
Dejan J. Trajkovski +5 more
wiley +1 more source