Quasi-static approximation in the study of compact stars

2021 ◽  
Author(s):  
Z. Yousaf ◽  
M.Z. Bhatti ◽  
U. Farwa
Keyword(s):  
Compact Stars ◽  
Static Approximation ◽  
Quasi Static Approximation

The role of advection in the quasi-static approximation

1994 ◽  
Vol 432 ◽  
pp. 302 ◽  
Author(s):  
Shlomi Pistinner ◽  
Giora Shaviv
Keyword(s):  
Static Approximation ◽  
Quasi Static Approximation

Sources of Fatigue in Random-Vibration Durability of Surface Mount Interconnects

2009 ◽  
Author(s):  
Y. Zhou ◽  
M. Al-Bassyiouni ◽  
A. Dasgupta
Keyword(s):  
Accumulation Rate ◽  
Random Excitation ◽  
Additional Stress ◽  
Dynamic Mode ◽  
Dynamic Prediction ◽  
Element Analysis ◽  
Static Approximation ◽  
Quasi Static Approximation ◽  
Dynamic Movement ◽  
Resonant Modes

The transient response of a PBGA256 assembly to random excitation is explored with quasi-static and transient finite element analysis, as well as with experiments. The quasi-static approximation is based on the first modal contribution to the measured PWB response. The dynamic prediction for solder strain and resulting damage accumulation rate are found to be significantly larger than in the quasi-static approximation. The quasi-static model is clearly missing additional stress drivers such as the dynamic movement of the component relative to the PWB and higher resonant modes of PWB flexure. The dynamic mode of the component is verified in this paper with two accelerometers placed on the component and on the PWB. Investigation of the higher modes of the PWB is deferred to a future study.

scholarly journals Cloaking Using the Anisotropic Multilayer Sphere

Photonics ◽  
2020 ◽  
Vol 7 (3) ◽  
pp. 52 ◽  
Author(s):  
Sidra Batool ◽  
Mehwish Nisar ◽  
Fabrizio Frezza ◽  
Fabio Mangini
Keyword(s):  
Mathematical Model ◽  
Arbitrary Number ◽  
Static Approximation ◽  
Quasi Static Approximation ◽  
Number Of Layers ◽  
Multilayer Sphere ◽  
Tangential Directions

We studied a Spherically Radially Anisotropic (SRA) multilayer sphere with an arbitrary number of layers. Within each layer permittivity components are different from each other in radial and tangential directions. Under the quasi-static approximation, we developed a more generalized mathematical model that can be used to calculate polarizability of the SRA multilayer sphere with any arbitrary number of layers. Moreover, the functionality of the SRA multilayer sphere as a cloak has been investigated. It has been shown that by choosing a suitable contrast between components of the permittivity, the SRA multilayer sphere can achieve threshold required for invisibility cloaking.

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