Results 31 to 40 of about 762 (219)

PROPERTIES OF GRAVITOTURBULENT ACCRETION DISKS [PDF]

open access: yesThe Astrophysical Journal, 2009
We explore the properties of cold gravitoturbulent accretion disks - non-fragmenting disks hovering on the verge of gravitational instability - using a realistic prescription for the effective viscosity caused by gravitational torques. This prescription is based on a direct relationship between the angular momentum transport in a thin accretion disk ...
openaire   +2 more sources

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

Radiatively Inefficient Accretion Disks [PDF]

open access: yes, 2001
To appear in: The neutron star black hole connection (NATO ASI ELOUNDA 1999) ed. C. Kouveliotou et al.
openaire   +2 more sources

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

On the Computation of Accretion Disk Spectra [PDF]

open access: yesAstrophysics and Space Science, 1987
AbstractSpectra of accretion disks in dwarf novae and some novalike stars have been computed. Many simplifications to the general model of the nature of a cataclysmic variable are needed to make the system numerically tractable. The necessity, justification, and implications of such simplifications are discussed together with the influences of some ...
openaire   +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

Numerical models of accretion disks [PDF]

open access: yesAIP Conference Proceedings, 1998
I review recent numerical studies of accretion disks, focusing on measurements of the turbulent shear stress, or $α$, in the shearing box model. I conclude with a list of astronomically relevant open questions that can be settled via future numerical experiments.
openaire   +2 more sources

Direct Metal Deposition of Graphene–Ti28Nb35.4Zr Matrix Composites With Enhanced Mechanical, Corrosion, and Biocompatibility Properties for Bone Implants

open access: yesAdvanced Engineering Materials, EarlyView.
Graphene nanoplatelet (0.1 wt.%) reinforcement significantly enhances the performance of β Ti‐28Nb‐35.4Zr alloy. Grain refinement, reduced water contact angle, and improved surface characteristics promote osteoblast adhesion and complete surface coverage after 7 days.
Khurram Munir   +5 more
wiley   +1 more source

Experimental Characterization and Constitutive Modeling of the Effect of Prior Inelastic Strain on the Viscoplastic Behavior of AD730 at 700 °C

open access: yesAdvanced Engineering Materials, EarlyView.
This study shows that superalloys used in aircraft engine disks become much more prone to deformation at high temperatures if they have been strained during manufacturing. This effect increases with the level of prior strain but eventually reaches a limit.
Fabio Machado Alves da Fonseca   +9 more
wiley   +1 more source

Viscosity Mechanisms in Accretion Disks [PDF]

open access: yesScience, 2000
The self-sustained turbulence that develops in magnetized accretion disks is suppressed in the weakly ionized, quiescent disks of close binary stars. Because accretion still proceeds during quiescence, another viscosity mechanism operates in these systems.
openaire   +3 more sources

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