scholarly journals LIDT-DD: A New Self-Consistent Debris Disc Model Including Radiation Pressure and Coupling Dynamical and Collisional Evolution

2013 ◽  
Vol 8 (S299) ◽  
pp. 346-347
Author(s):  
Q. Kral ◽  
P. Thebault ◽  
S. Charnoz
Keyword(s):  
Radiation Pressure ◽  
New Model ◽  
Disc Model ◽  
Self Consistent ◽  
Radiation Forces ◽  
Coupling Dynamics ◽  
Long Timescales ◽  
Collisional Evolution

AbstractThe first attempt at developing a fully self-consistent code coupling dynamics and collisions to study debris discs (Kral et al. 2013) is presented. So far, these two crucial mechanisms were studied separately, with N-body and statistical collisional codes respectively, because of stringent computational constraints.We present a new model named LIDT-DD which is able to follow over long timescales the coupled evolution of dynamics (including radiation forces) and collisions in a self-consistent way.

New Model for Calculation of Solvation Free Energies:  Correction of Self-Consistent Reaction Field Continuum Dielectric Theory for Short-Range Hydrogen-Bonding Effects

1996 ◽  
Vol 100 (28) ◽  
pp. 11775-11788 ◽  
Author(s):  
Bryan Marten ◽  
Kyungsun Kim ◽  
Christian Cortis ◽  
Richard A. Friesner ◽  
Robert B. Murphy ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Short Range ◽  
Free Energies ◽  
New Model ◽  
Reaction Field ◽  
Self Consistent ◽  
Solvation Free Energies

scholarly journals New X-shaped bulge photometric model as a tool for measuring B/PS bulges and their X-structures in photometric studies

2020 ◽  
Vol 499 (1) ◽  
pp. 462-481
Author(s):  
Anton A Smirnov ◽  
Sergey S Savchenko
Keyword(s):  
Half Plane ◽  
Numerical Models ◽  
Spectral Characteristics ◽  
Analytical Models ◽  
Structure Parameters ◽  
New Model ◽  
Self Consistent ◽  
The Galaxy ◽  
Galaxy Model ◽  
Upper Half Plane

ABSTRACT Recent orbital studies of 3D bar structure in various numerical and analytical models show that X-structures that reside in boxy/peanut-shaped (B/PS) bulges are not delineated by some specific type of orbits, but are natural parts of them and formed by the same orbits that constitute such bulges. This implies that to accurately account for B/PS bulges and their X-structures in photometric studies, one needs the photometric model of B/PS bulge that includes an X-structure as its natural part. To find such a model, we considered a self-consistent numerical galaxy model where a typical B/PS bulge arises. Using spectral characteristics of particle-‘stars’, we decomposed the galaxy model on to the bar and non-bar components. We used the extracted 3D bar component to find an appropriate B/PS bulge photometric model, which can account for X-structures residing in such bulges. The resulted B/PS bulge photometric model has a truncated 2D Sersic profile with truncations introduced above (in the upper half-plane) and below (in the bottom half-plane) the rays of X-structures. We applied this model to represent B/PS bulges of various numerical models and some real galaxies. The comparison with previous works revealed that there are systematic shifts between the X-structure parameters of the same galaxies measured within the different approaches. We found that the geometric parameters of X-structures of real and modelled galaxies are consistent with each other if we measure them using our new model.

scholarly journals The domain of radiatively driven mass loss in the H-R diagram

1979 ◽  
Vol 83 ◽  
pp. 235-240 ◽  
Author(s):  
David C. Abbott
Keyword(s):  
Steady State ◽  
Mass Loss ◽  
Radiation Pressure ◽  
Effective Temperature ◽  
Stellar Wind ◽  
Radiation Force ◽  
Theoretical Uncertainty ◽  
Line Radiation ◽  
Consistent Model ◽  
Self Consistent

Previous work by Castor, Abbott, and Klein (1975) presented a self-consistent model of a steady-state stellar wind. They also showed qualitatively that for O stars at least a static atmosphere could not exist. This paper extends that result by calculating in detail the minimum luminosity as a function of effective temperature required for the line radiation force to exceed gravity. Within the observational and theoretical uncertainty there is a one-to-one correspondence between a star's calculated ability to self-initiate a stellar wind by radiation pressure alone and the observed presence of outflowing material in the UV resonance lines.

scholarly journals Quantitative Prediction of Cold Rolling Textures in Low-Carbon Steel by Means of the Lamel Model

1999 ◽  
Vol 31 (3) ◽  
pp. 109-149 ◽  
Author(s):  
P. Van Houtte ◽  
L. Delannay ◽  
I. Samajdar
Keyword(s):  
Carbon Steel ◽  
Cold Rolling ◽  
Low Carbon Steel ◽  
Quantitative Prediction ◽  
Low Carbon ◽  
New Model ◽  
Taylor Models ◽  
Consistent Model ◽  
Self Consistent ◽  
Further Development

Rolling textures of low-carbon steel predicted by full constraints and relaxed constraints Taylor models, as well by a self-consistent model, are quantitatively compared to experimental results. It appears that none of these models really performs well, the best results being obtained by the Pancake model. Anew model (“Lamel model”) is then proposed as a further development of the Pancake model. It treats a stack of two lamella-shaped grains at a time. The new model is described in detail, after which the results obtained for rolling of low-carbon steel are discussed. The prediction of the overall texture now is quantitatively correct. However, the γ-fibre components are better predicted than the α-fibre ones. Finally it is concluded that further work is necessary, as the same kind of success is not guaranteed for other cases, such as rolling of f.c.c, materials.

scholarly journals The Specification of Nutation in the IAU System of Astronomical Constants

1980 ◽  
Vol 78 ◽  
pp. 1-7
Author(s):  
G. A. Wilkins
Keyword(s):  
Rigid Body ◽  
Elastic Properties ◽  
Principal Term ◽  
The Sun ◽  
New Model ◽  
The Earth ◽  
Self Consistent ◽  
Rotation Of The Earth ◽  
Astronomical Constants

The principal purpose of the IAU system of astronomical constants is to provide a self-consistent set of constants for use in the computation of the international ephemerides of the Sun, Moon, planets and stars and in the reduction of observations of these bodies. At present nutation is computed from a theory of the rotation of the Earth as a rigid body and only the coefficient of the principal term in obliquity is specified in the system of constants. Such a simple specification will not be adequate for use with the more precise observations that are becoming available, and it appears that it will be necessary to adopt a new model of the Earth and to develop a new theory of nutation which will take into account the elastic properties of the Earth. The new model should be consistent with other constants of the IAU system, and with the model used in other branches of geophysics. The new specification of nutation should be formally adopted by the IAU in 1979 so that it can be used in the published ephemerides for 1984 onwards.

scholarly journals Inclusion of Quantum Confinement Effects in Self-Consistent Monte Carlo Device Simulations

VLSI Design ◽  
1998 ◽  
Vol 8 (1-4) ◽  
pp. 21-27
Author(s):  
R. W. Kelsall ◽  
A. J. Lidsey
Keyword(s):  
Monte Carlo ◽  
Quantum Confinement ◽  
Monte Carlo Model ◽  
Explicit Calculation ◽  
Quantum Model ◽  
Confinement Effects ◽  
New Model ◽  
Monte Carlo Algorithms ◽  
Quantum Confinement Effects ◽  
Self Consistent

The design of Monte Carlo FET simulations is discussed, with specific attention to the methods used to describe quantum confinement effects. A new model is presented, which employs self-consistent coupling of Schrodinger, Poisson and Monte Carlo algorithms, and explicit calculation of the scattering rates between confined and unconfined states. Comparisons between the new model and a standard semi-classical Monte Carlo model are presented for a 0.1 μm gate-length In0.52Al0.48As/In0.53 Ga0.47As/InP MODFET. Whilst the quantum model yields minor corrections in the predicted output characteristics, it is found that these results can be achieved without repeated iterations of the Schrodinger equation.

scholarly journals The wind of P Cygni

1989 ◽  
Vol 113 ◽  
pp. 259-260
Author(s):  
J. Puls ◽  
A.W.A. Pauldrach ◽  
R.P. Kudritzki
Keyword(s):  
Energy Distribution ◽  
Mass Loss ◽  
Radiation Pressure ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Terminal Velocity ◽  
Scaling Relations ◽  
Self Consistent ◽  
Line Pressure ◽  
Eddington Limit

The stationary features of the wind of P Cygni are considerably different from those of ‘normal’ supergiant winds with comparable luminosity. In contrast to such winds, which are generally accepted to be driven by radiation pressure, P Cygni’s mass-loss rate is higher by a factor of 5, the terminal velocity is higher by a factor of 10, and the velocity law itself is much flatter than would be expected from a first glance at glance at typical scaling relations. However, these relations depend crucially and non-linearly on the star’s distance from the Eddington limit, which for P Cyg is very small (see below). Here we investigate whether the acceleration mechanism of P Cygni’s wind can also be explained by line pressure and to what extent self-consistent wind models represent the observed quantities (especially the IR energy distribution).

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