Results 181 to 190 of about 79,734 (334)

On spacelike hypersurfaces with constant scalar curvature in the de Sitter space

open access: yes, 2007
We classify spacelike hypersurfaces of the de Sitter space S1n+1(c) with constant scalar curvature and with two principal curvatures. Moreover, we prove that if Mn is a complete spacelike hypersurface with constant scalar curvature n(n−1)R and with two ...
Scherfner, Mike, Hu, Zejun, Zhai, Shujie
core   +1 more source

Fatigue Crack Initiation and Growth in Nanocrystalline Ni at Multiple Length‐Scales

open access: yesAdvanced Engineering Materials, EarlyView.
Overview of miniaturized in situ SEM fatigue setup and resultant fatigue crack growth data for nanocrystalline Ni. The presented study focuses on the analysis of fatigue crack growth rate (FCGR) in focused ion beam‐notched microcantilevers prepared from nanocrystalline (NC) Ni as a model material.
Igor Moravcik   +7 more
wiley   +1 more source

Yamabe flow and metrics of constant scalar curvature on a complete manifold

open access: yesCalculus of Variations and Partial Differential Equations, 2019
Li Ma
semanticscholar   +1 more source

THE SASAKI JOIN, HAMILTONIAN 2-FORMS, AND CONSTANT SCALAR CURVATURE

open access: yes, 2015
We describe a general procedure for constructing new Sasaki metrics of constant scalar curvature (CSC) from old ones. Explicitly, we begin with a regular Sasaki metric of constant scalar curvature on a 2n + 1-dimensional compact manifold M and con-struct
Christina W. Tønnesen-Friedman   +1 more
core  

Creep‐Induced Microstructural Evolution in an A2‐B2 Superalloy

open access: yesAdvanced Engineering Materials, EarlyView.
A 27.3Ta‐27.3Mo‐27.3Ti‐8Cr‐10Al (at.%) refractory high‐entropy alloy with precipitation‐strengthened A2‐B2 microstructure was studied by creep tests at 1030°C, which demonstrate a transition in deformation mechanisms in the range of 100–150 MPa applied stress. This is associated with changes in dislocation–precipitate interactions. Relevant deformation
Liu Yang   +10 more
wiley   +1 more source

Influence of Test Temperature and Test Frequency on Fatigue Life of Aluminum Alloy EN AW‐2618A

open access: yesAdvanced Engineering Materials, EarlyView.
The influence of test temperature and test frequency on the fatigue life of EN AW‐2618A is investigated. High‐cycle fatigue tests are performed at different test temperatures and frequencies on the 1000 h/230°C overaged state. Both test parameters reduce fatigue life due to time‐dependent damage mechanisms.
Ying Han   +5 more
wiley   +1 more source

Dynamical mechanism of vacuum energy compensation

open access: yesEuropean Physical Journal C: Particles and Fields
The model of vacuum energy compensation due to interaction of a scalar field $$\phi $$ ϕ with curvature scalar of the form $$\beta R \phi ^2 f(\phi ) $$ β R ϕ 2 f ( ϕ ) is proposed.
E. V. Arbuzova, A. D. Dolgov
doaj   +1 more source

High‐Temperature Nanoindentation of Metals: Assessing Thermal Drift, Frame Compliance, and Chemical Composition Effects on the Reported Mechanical Properties

open access: yesAdvanced Engineering Materials, EarlyView.
Do not let thermal drift and instrument artifacts deceive high‐temperature nanoindentation results. We compare classical Oliver–Pharr and automatic image recognition analyses across steels and a Ni alloy to quantify these effects. Accounting for artifacts reveals systematic softening with temperature, while Cr and Ni additions boost resistance ...
Velislava Yonkova   +2 more
wiley   +1 more source

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

open access: yesAdvanced 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   +9 more
wiley   +1 more source

Recycling of NiTi Shape Memory Alloys: Fundamental and Technological Aspects of a Vacuum Induction Melting Processing Route

open access: yesAdvanced Engineering Materials, EarlyView.
The present study investigates recycling of NiTi shape memory alloys via vacuum induction melting. An ingot was synthesized from elemental Ni and Ti and subjected to three subsequent remelting cycles. Remelting increases process durations and impurity levels and adversely affects microstructures and functional properties.
Sakia Sophia Noorzayee   +7 more
wiley   +1 more source

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