Results 111 to 120 of about 9,614 (265)

Hα Emission among Evolved FGKM Stars: A Compendium from the Literature

The Astronomical Journal
Emission in the wings of the H α line among late-type giant stars occurs as a consequence of conditions in their chromospheres. Data from the literature have been used to document the incidence of H α emission among Population I giant stars as a function
Graeme H. Smith
doaj   +1 more source

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

Advanced 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, Julian M. Rosalie, Jan Radners, Mauro Madia, Philipp von Hartrott, Birgit Skrotzki   +5 more
wiley   +1 more source

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

Advanced 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, Steffen Brinckmann, Ruth Schwaiger   +2 more
wiley   +1 more source

Accretion Properties of the Young Brown Dwarf 2MASS J08440915-7833457

The Astrophysical Journal
We present Hubble Space Telescope Cosmic Origins Spectrograph far-ultraviolet (FUV) and Space Telescope Imaging Spectrometer (STIS) optical observations toward the young accreting brown dwarf 2MASS J08440915-7833457 (J0844) from the UV Legacy Library of ...
Toni V. Panzera, Laura S. Flagg, Margaret A. Mueller, Christopher M. Johns-Krull, Gregory J. Herczeg   +4 more
doaj   +1 more source

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

Advanced 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, Son Tung Mai, Sarath Menon, Braulio Gadiel Sánchez Ortega, Ralf Drautz, Alexander Kauffmann, Gunther Eggeler, Jan Frenzel   +7 more
wiley   +1 more source

Classification of Wolf–Rayet Stars from LAMOST DR10

The Astrophysical Journal Supplement Series
Wolf–Rayet (WR) stars are highly evolved descendants of the most massive initial stellar populations, serving as essential tracers in stellar evolution. Despite the progress made in their study, a more comprehensive population census is still required to
Jirui Chang, Wenyu Wang, Meixia Qu, Kun Su, Liangping Tu, Chenyang Lv, Bin Jiang, Yanxia Zhang   +7 more
doaj   +1 more source

Current Status and Challenges in Data Collection for Aerospace Coatings Deposited by Plasma Spraying

Advanced Engineering Materials, EarlyView.
An innovative approach has been integrated into the GRENAT project to optimize plasma spraying and coating performance. Raw materials are accelerated and melted in the plasma generated by torches, creating coatings. Monitoring sensors collect process data which are combined with ex situ characterization data.
Lila Randriamananjara, Vincent Rat, Quentin Dubreuil, Patrice Valorge, Simon Goutier, Alain Denoirjean, Olivier Messe, Céline Ruelle, Jean‐Philippe Poli   +8 more
wiley   +1 more source

In Situ Micromechanical Study of Bimodal γ′–γ″ Precipitate Assemblies in Ni–Cr–Al–Nb Superalloy

Advanced Engineering Materials, EarlyView.
A Ni–Cr–Al–Nb superalloy with a bimodal γ′–γ″ precipitate distribution is developed. Composite precipitate assemblies form through heterogeneous nucleation, effectively impeding dislocation motion. Micropillar compression reveals high strength at room and elevated temperatures, governed by precipitate shearing, with coupled faulting mechanisms ...
Ujjval Bansal, Tae‐Hyeok Kang, Pyuck‐Pa Choi, Subin Lee, Christoph Kirchlechner   +4 more
wiley   +1 more source

Empirical Prediction of Plasma Emission Measure Distributions and X-Ray/Extreme-ultraviolet Spectra of Late-type Stars

The Astrophysical Journal
High-energy emission spectra from the outer atmospheres of late-type stars represent an important feature of the stellar activity in several contexts, such as the photoevaporation and photochemistry of planetary atmospheres or the modeling of irradiated ...
A. Maggio, I. Pillitteri, J. Sanz-Forcada, G. Micela   +3 more
doaj   +1 more source

Kelvin waves over a differentially rotating spherical shell

Astronomy & Astrophysics
Context. Be stars are currently viewed as B-type stars surrounded by a disc fuelled by the star itself during episodic excretion events. The origin of these events is poorly understood. Aims. This study aims to determine whether surface equatorial Kelvin
Boismard T., Rieutord M.
doaj   +1 more source