Results 91 to 100 of about 9,614 (265)

Emission-line stars in the LMC: the Armagh survey and a metacatalogue [PDF]

Astronomy & Astrophysics, 2013
[Aims] Accurate astrometry is required to reliably cross-match 20th-century photographic catalogues against 21st-century digital surveys. The present work provides modern-era identifications and astrometry for the 801 emission-line objects "of stellar appearance" in the Armagh survey (the largest of its nature to date).
openaire   +2 more sources

Thermodynamic Pathways of Nonequilibrium Solidification in Wire‐Arc Additive Manufacturing Fe‐Based Multicomponent Alloy Structures

Advanced Engineering Materials, EarlyView.
Geometry‐driven thermal behavior in wire‐arc additive manufacturing (WAAM) influences microstructural evolution during nonequilibrium solidification of a chemically complex Fe–Cr–Nb–W–Mo–C nanocomposite system. By comparing different deposits configurations, distinct entropy–cooling rate correlations, segregation, and carbide evolution are revealed ...
Blanca Palacios, Anthony Gonzalez, Aleksander Aleman, Tyler Dolmetsch, Tanaji Paul, Arvind Agarwal   +5 more
wiley   +1 more source

HdBe stars: hydrogen-deficient supergiants with emission lines [PDF]

Symposium - International Astronomical Union, 1994
The hydrogen-deficient B stars (often known as extreme-helium stars: EHes) show weak or absent Balmer lines and the following properties (Heber 1986a): Teff ~ 12 − 25kK, log g ~ 2 − 3, log nH ~ −3 − −4, nHe ≈ 0.99, nC ~ 0.01. Their galactic positions and apparent magnitudes indicate that they are low-mass supergiants belonging to the Galactic bulge ...
openaire   +1 more source

Thermomechanical Fatigue and Creep–Fatigue Interaction of Inconel 718 Additively Manufactured by Laser Beam Powder Bed Fusion

Advanced Engineering Materials, EarlyView.
Thermomechanical fatigue tests of laser beam powder bed fusion (PBF‐LB) Inconel 718 show that the additively manufactured material reaches almost the lifetimes of conventionally‐rolled material under no‐dwell conditions. Introducing dwell times at the maximum temperature markedly reduces the lifetimes due to pronounced grain boundary sliding associated
Stefan Guth, Tomáš Babinský, Jan Lars Riedel, Wen Hao Kan, Aijun Huang, Martin Heilmaier, Ivo Šulák   +6 more
wiley   +1 more source

Low‐Angle Grain Boundaries and Re‐Segregation in Single‐Crystalline Ni‐Base Superalloys

Advanced Engineering Materials, EarlyView.
This work demonstrates that Re‐segregation at low‐angle grain boundaries (LAGBs) in Ni‐base superalloys is influenced by misorientation angle. Advanced microscopy and atom probe tomography reveal that higher misorientation angles increases Re‐segregation.
Alireza B. Parsa, Aparna Saksena, Alesander Kostka, Pascal Thome, Felicitas Scholz, Alexandre Mussi, Christoph Somsen, Baptiste Gault, Jan Frenzel, Gunther Eggeler   +9 more
wiley   +1 more source

Creating Ti–Fe α/β Alloys by Diffusion‐Driven Solid‐State Processing

Advanced Engineering Materials, EarlyView.
This study proposes making alloys containing fast diffusing elements that are difficult to produce by ingot metallurgy, by diffusion‐driven solid‐state HIP processing of elemental powders and low‐temperature homogenisation. Here, novel Fe‐Ti α–β alloys are formed having fine α–β lamellae, a small β prior grain size without significant intermetallics ...
Jiaqi Xu, Xun Zhang, Jack M. Donoghue, Albert D. Smith, Rahul Unnikrishnan, Rhys Thomas, Vahid Nekouie, Jie Luo, Dongchen Hu, Michael Preuss, Philip J. Withers   +10 more
wiley   +1 more source

OH/IR stars in the inner Galactic bulge

Astronomy & Astrophysics
Context. Stars on the asymptotic giant branch (AGB) play important roles in a number of astronomical contexts. To quantify these roles, it is necessary to establish the mass-loss characteristics of stars as they evolve up and beyond the AGB. Aims.
Olofsson H., Khouri T., Muller S., Unnikrishnan R., Groenewegen M. A. T., Blommaert J. A. D. L., De Beck E., Kastner J. H., Maercker M., Patel N., Ryde N., Sargent B. A., Srinivasan S., Vlemmings W. H. T.   +13 more
doaj   +1 more source

Long-Term Spectroscopic Monitoring and Surveys of Early-Type Stars with and without Circumstellar Envelopes

Open Astronomy, 2017
Ongoing studies of different groups of stars result in improving our knowledge of their fundamental parameters and evolutionary status. Also, they result in finding new phases of stellar evolution, which require theoretical explanation. At the same time,
Miroshnichenko Anatoly S., Danford Steven, Zharikov Sergei V., Manset Nadine, Levato Hugo, Grosso Monica, Korčáková Daniela, Kusakin Anatoly V., Khokhlov Serik A., Prendergast Peter   +9 more
doaj   +1 more source

Solid‐State Diffusion and Intermetallic Phase Formation in Roll‐Bonded Mg–Zn Composites With Kirigami‐Patterned Inlay

Advanced Engineering Materials, EarlyView.
Mg–Zn composites with a thickness of 0.21 mm were fabricated using roll bonding of a kirigami‐patterned Mg alloy inlay within a Zn matrix. Thermal activation following this process led to the formation of tailored intermetallic structures, which provided the composite with enhanced flexural strength.
Yaroslav Frolov, Oleksandr Bobukh, Christian Klose, Florian Nürnberger, Hans Jürgen Maier   +4 more
wiley   +1 more source

ExoplaNeT accRetion mOnitoring sPectroscopic surveY (ENTROPY)

Astronomy & Astrophysics
Context. Observations of helium emission lines from classical T Tauri stars at high resolution (Rλ > 10 000) offer great potential, showing distinct profile characteristics that help probe regions within the accretion geometry untapped by hydrogen lines.
Viswanath Gayathri, Bonnefoy Mickaël, Dougados Catherine, Ringqvist Simon C., Janson Markus, Demars Dorian, Sicilia-Aguilar Aurora, Bouvier Jérôme, Marleau Gabriel-Dominique, Alecian Evelyne, Chauvin Gaël   +10 more
doaj   +1 more source