Results 71 to 80 of about 1,033,209 (296)

Lanczos–Lovelock models of gravity [PDF]

Physics Reports, 2013
Lanczos-Lovelock models of gravity represent a natural and elegant generalization of Einstein's theory of gravity to higher dimensions. They are characterized by the fact that the field equations only contain up to second derivatives of the metric even though the action functional can be a quadratic or higher degree polynomial in the curvature tensor ...
Padmanabhan, T., Kothawala, D.
openaire   +3 more sources

Design and Prototyping of Topology‐Optimized, Additively Manufactured Lightweight Components for Space Robotic Systems: A Case Study

Advanced Engineering Materials, EarlyView.
The results demonstrate a simulation‐driven workflow that applies LSB topology optimization with additive manufacturing constraints to mission‐specific load cases, integrating European Cooperation for Space Standardization compliant verification and manufacturability to develop structurally efficient rover suspension components.
Stelios K. Georgantzinos, Grigorios Kostopoulos, Eleni Papadopoulou, Stefanos Voulgaris, Alexandra Tseni, Panteleimon Bakalis, Maria N. Gkara, Chara Ch. Mitropoulou, Georgios Kazakis, Alin Munteanu, Jeremi Gancet, Nikos D. Lagaros   +11 more
wiley   +1 more source

Transfer of Energy and Momentum Between Magnetoactive Surface Microstructure and a Solid Object

Advanced Engineering Materials, EarlyView.
We demonstrate that magnetoactive multilamellar arrays subjected to a rotating magnetic field can function as platforms for controlled transport of physical objects. Through systematic experimental investigation, we elucidate the underlying physical mechanisms determining the upper limit of the achievable transportation speed in such magnetic “conveyor‐
Arne Geldof, Jan Kopačin, Izidor Straus, Raphael Kriegl, Gaia Kravanja, Luka Hribar, Matija Jezeršek, Mikhail Shamonin, Gašper Kokot, Irena Drevenšek‐Olenik   +9 more
wiley   +1 more source

Inflammatory Response‐Inspired Thermochromic Shield for Pneumatic Structures

Advanced Engineering Materials, EarlyView.
A thermochromic shield for pneumatic structures is developed, using anhydrous sodium acetate powder and thermochromic pigment‐included solution. In this shield composed of three layers, the exothermic and thermochromic reactions, followed by the mixture of both components, occur promptly with an incident of penetrating damage as a sign of initial ...
Hyun Jae Lee, Ryuma Niiyama
wiley   +1 more source

A New Combination Approach for Gibbs Phenomenon Suppression in Regional Validation of Global Gravity Field Model: A Case Study in North China

Remote Sensing
A global gravity field model (GGM) is essential to be validated with ground-based or airborne observational data for the accurate application of the GGM at a regional scale.
Yingchun Shen, Wei Feng, Meng Yang, Min Zhong, Wei Tian, Yuhao Xiong, Zhongshan Jiang   +6 more
doaj   +1 more source

Quantum gravity and the standard model

, 2006
We show that a class of background independent models of quantum spacetime have local excitations that can be mapped to the first generation fermions of the standard model of particle physics.
Alexander S, Ambjorn J Jurkiewicz J Loll R, Another approach to the emergence of matter in spin foam models is, Bilson-Thompson S O, Borissov R, Chang L N, Chang L N Soo C, Fotini Markopoulou, Freidel L Livine E R, Freidel L Minic D Takeuchi T, Hackett J, Hooft G, Kauffman L H, Konopka T Markopoulou F, Kribs D W Markopoulou F, Lee Smolin, Lloyd S, Majid S, Markopoulou F, Markopoulou F Dreyer O, Markopoulou F Poulin D, Perez A Rovell C, Rovelli C, Rovelli C, Rovelli C, Smolin L, Smolin L, Sundance O Bilson-Thompson   +27 more
core   +1 more source

Arctan-Gravity Model [PDF]

Universe, 2015
A new gravity model with the function F(R) = (1/β) arctan (βR – β2R2) instead of the Ricci scalar in the Einstein–Hilbert action, describing inflation of the Universe, is suggested and analyzed. We obtain constant curvature solutions of the model in the Jordan frame. Performing the conformal transformation of the metric, the potential and the mass of a
openaire   +2 more sources

Exploring Dipolar Dynamics and Ionic Transport in Metal‐Organic Frameworks: Experimental and Theoretical Insights

Advanced Functional Materials, EarlyView.
In this study, the interplay of dipolar dynamics and ionic charge transport in MOF compounds is investigated. Synthesizing the novel structure CFA‐25 with integrated freely rotating dipolar groups, local and macroscopic effects, including interactions with Cs cations are explored.
Ralph Freund, Arthur Schulz, Peter Lunkenheimer, Maryana Kraft, Thomas Bergler, Harald Oberhofer, Dirk Volkmer   +6 more
wiley   +1 more source

Refining satellite Altimetry-Derived gravity anomaly model with shipborne gravity using multilayer perceptron neural networks

Scientific Reports
This study refines the gravity anomaly model derived from altimetry data by employing a multilayer perceptron (MLP) neural network to integrate multi-source geophysical data (longitude, latitude, gravity anomaly, geoid height, bathymetry, and sediment ...
Chengjun Xiao, Jinyun Guo, Chengcheng Zhu, Hui Li, Shangguo Liu, Xin Liu   +5 more
doaj   +1 more source

Synthetic Demand Flow Generation Using the Proximity Factor

Forecasting
One of the biggest challenges in designing a logistics network is predicting the demand flows between all pairs of points in the network. Currently, the gravity model is mainly used for estimating the demand flow between points.
Ekin Yalvac, Michael G. Kay
doaj   +1 more source