Results 61 to 70 of about 351 (243)

Instabilities in metric-affine theories of gravity with higher order curvature terms

European Physical Journal C: Particles and Fields, 2020
We discuss the presence of ghostly instabilities for metric-affine theories constructed with higher order curvature terms. We mainly focus on theories containing only the Ricci tensor and show the crucial role played by the projective symmetry.
Jose Beltrán Jiménez, Adrià Delhom
doaj   +1 more source

A Note on the Geometry of RW Space-Times

Mathematics, 2023
A conformally flat GRW space-time is a perfect fluid RW space-time. In this note, we investigated the influence of many differential curvature conditions, such as the existence of recurrent and semi-symmetric curvature tensors.
Sameh Shenawy, Uday Chand De, Nasser Bin Turki   +2 more
doaj   +1 more source

Creep Properties and Deformation Mechanism of Additively Manufactured NiAl‐CrMo Composites

Advanced Engineering Materials, EarlyView.
Additively manufactured NiAl‐CrMo composites contain numerous interfaces and cell boundaries that control their creep response. At 700°C under high applied stress, creep is dominated by dislocation‐controlled power‐law mechanisms. At 800°C–900°C and lower stresses, creep is primarily diffusion‐controlled along cell boundaries.
Jan Vollhüter, Andreas Bezold, Johan Westraadt, Katharina Fiegl, Subham Chattoraj, Benjamin Wahlmann, Carolin Körner, Michael Mills, Mathias Göken, Steffen Neumeier   +9 more
wiley   +1 more source

Ontology‐Aligned Structuring and Reuse of Multimodal Materials Data and Workflows Toward Automatic Reproduction

Advanced Engineering Materials, EarlyView.
Reproduction of stacking fault energy calculations from literature with a semi‐automated large language model‐assisted extraction procedure: extraction of simulation protocol, atomistic structures, computational parameters, and reported results, ontology alignment, knowledge graph construction and, finally, recomputation forvalidation.
Sepideh Baghaee Ravari, Abril Azocar Guzman, Sarath Menon, Stefan Sandfeld, Tilmann Hickel, Markus Stricker   +5 more
wiley   +1 more source

Toward Knowledge‐Based Workflows: A Semantic Approach to Atomistic Simulations for Mechanical and Thermodynamic Properties

Advanced Engineering Materials, EarlyView.
Knowledge‐based atomistic workflows are presented for mechanical and thermodynamic properties. By coupling modular simulations with ontology‐aligned metadata and provenance, Fe case studies on elastic behavior, defects, thermal properties, and Hall–Petch strengthening reveal how FAIR, queryable, and reusable simulation data can be generated. Mechanical
Abril Azócar Guzmán, Hoang‐Thien Luu, Sarath Menon, Tilmann Hickel, Nina Merkert, Stefan Sandfeld   +5 more
wiley   +1 more source

From Shear to Sound: Mechanics–Acoustics Mapping of TPMS Lattices

Advanced Engineering Materials, EarlyView.
Triply periodic minimal surface (TPMS) lattices are mapped across mechanical and acoustic performance, revealing that descriptors validated in compression fail under shear. First‐time comparison with trusses included. A transition from porous to resonance‐driven absorption emerges at 25% density.
Lucía Doyle, María Ángeles Navacerrada, Johan Christensen, Carlos González   +3 more
wiley   +1 more source

Some Remarks on Fourth-Order Tensor Fields on Space-Times

Mathematics
This paper is a contribution to Einstein’s general relativity theory and is mostly a review of known work. It concentrates attention on four fourth-order tensors which arise on the space-time manifold describing this theory and which are very useful ...
Graham Hall
doaj   +1 more source

Influence of Geometric Design on Mechanical Performance of Auxetic Metastructure

Advanced Engineering Materials, EarlyView.
Strategic geometric reinforcement transforms auxetic performance. This study evaluates 3D‐printed arrowhead metastructures, revealing that a modified design with local ring reinforcement suppresses premature failure to achieve superior energy absorption and structural efficiency.
Muhammad Gulzari, Supharoek Sornsomrit, Muhammad Ayaz Akbar, Stephan Rudykh   +3 more
wiley   +1 more source

Hierarchy of spaces of projective connection

Дифференциальная геометрия многообразий фигур, 2018
We consider the bundle of projective frames over a smooth manifold, i. e. the principal bundle whose typical fiber is the projective group. The giving fundamental-group connection in this bundle transforms it into a space of general projective connection.
Yu. Shevchenko
doaj  

Index of pseudo-projectively-symmetric semi-Riemannian manifolds

Karpatsʹkì Matematičnì Publìkacìï, 2015
The index of $\widetilde{\nabla}$-pseudo-projectively symmetric and in particular for $\widetilde{\nabla}$-projectively symmetric semi-Riemannian manifolds, where $\widetilde{\nabla}$ is Ricci symmetric metric connection, are discussed.
P. Gupta
doaj   +1 more source