scholarly journals A Radio Flare from GRB 020405: Evidence for a Uniform Medium around a Massive Stellar Progenitor

2003 ◽  
Vol 587 (1) ◽  
pp. L5-L8 ◽  
Author(s):  
E. Berger ◽  
A. M. Soderberg ◽  
D. A. Frail ◽  
S. R. Kulkarni
Keyword(s):  
Uniform Medium ◽  
Radio Flare

scholarly journals A numerical frame work of magnetically driven Powell-Eyring nanofluid using single phase model

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Wasim Jamshed ◽  
Mohamed R. Eid ◽  
Kottakkaran Sooppy Nisar ◽  
Nor Ain Azeany Mohd Nasir ◽  
Abhilash Edacherian ◽  
...  
Keyword(s):  
Differential Equations ◽  
Numerical Solutions ◽  
Volume Fraction ◽  
Dissipative Flow ◽  
Uniform Medium ◽  
Heat Transport Properties ◽  
Flow Heat ◽  
Frame Work ◽  
Slippery Surface ◽  
Nanoparticle Shapes

AbstractThe current investigation aims to examine heat transfer as well as entropy generation analysis of Powell-Eyring nanofluid moving over a linearly expandable non-uniform medium. The nanofluid is investigated in terms of heat transport properties subjected to a convectively heated slippery surface. The effect of a magnetic field, porous medium, radiative flux, nanoparticle shapes, viscous dissipative flow, heat source, and Joule heating are also included in this analysis. The modeled equations regarding flow phenomenon are presented in the form of partial-differential equations (PDEs). Keller-box technique is utilized to detect the numerical solutions of modeled equations transformed into ordinary-differential equations (ODEs) via suitable similarity conversions. Two different nanofluids, Copper-methanol (Cu-MeOH) as well as Graphene oxide-methanol (GO-MeOH) have been taken for our study. Substantial results in terms of sundry variables against heat, frictional force, Nusselt number, and entropy production are elaborate graphically. This work’s noteworthy conclusion is that the thermal conductivity in Powell-Eyring phenomena steadily increases in contrast to classical liquid. The system’s entropy escalates in the case of volume fraction of nanoparticles, material parameters, and thermal radiation. The shape factor is more significant and it has a very clear effect on entropy rate in the case of GO-MeOH nanofluid than Cu-MeOH nanofluid.

scholarly journals The behaviour of electrolytes in mixed solvents. Part I.—The free energies and heat contents of hydrogen chloride in water—Ethyl alcohol solutions

1929 ◽  
Vol 125 (799) ◽  
pp. 694-712 ◽  
Keyword(s):  
Hydrogen Chloride ◽  
Electric Fields ◽  
Mixed Solvents ◽  
Dielectric Constants ◽  
Free Energies ◽  
Dissolved Ions ◽  
Uniform Medium ◽  
The Mean ◽  
Solvent Molecules ◽  
Water Alcohol

Previous studies on the effect of a change of medium on tire properties of dissolved electrolytes have aimed at correlating the behaviour of the electrolyte with the mean physical properties, e. g ., dielectric constants, of the medium. While this approach may be justified in the case of solvents containing molecules of only one kind, it is not sufficient to regard a mixed solvent as a uniform medium affecting the dissolved ions solely through the effect of its dielectric constant on the electric forces between them. For the electric fields of ions exert a differential attraction on molecules possessing different degrees of polarisability and since tire more polarisable molecules must tend to congregate round the ions, the properties of the latter cannot depend solely on tire mean properties of tire medium. Studies on the behaviour of ions in such cases will throw light on the interaction between ions and solvent molecules. The present paper gives tire results of measurements of the free energies and heat contents of hydrogen chloride in water-alcohol solutions, obtained by determining the electromotive forces of cells of the type:— H 2 ( g ) | HCl ( m ), AgCl ( s ) | Ag water-alcohol

scholarly journals A 1.3 cm wavelength radio flare from a deeply embedded source in the Orion BN/KL region

2007 ◽  
Vol 477 (1) ◽  
pp. 267-272 ◽  
Author(s):  
J. Forbrich ◽  
K. M. Menten ◽  
M. J. Reid
Keyword(s):  
Radio Flare

scholarly journals 7.14. Gaseous accretion flows in the inner parsec of the Galaxy

1998 ◽  
Vol 184 ◽  
pp. 319-320 ◽  
Author(s):  
Robert Coker ◽  
Fulvio Melia
Keyword(s):  
Galactic Nuclei ◽  
Accretion Flows ◽  
Set Constraints ◽  
Central Engine ◽  
Accretion Rates ◽  
The Galaxy ◽  
Gaseous Flows ◽  
Uniform Medium ◽  
Sgr A ◽  
Central Concentration

Many characteristics of galactic nuclei may be associated with the accretion of ambient gas by a central concentration of mass. Using a 3D hydrodynamical code, we have been simulating this accretion process for Sgr A∗, the compact nonthermal source at the center of the Milky Way, in order to realistically model the gaseous flows in the inner parsec of our Galaxy. In the most recent simulations, we have taken into account the multi-point-like distribution of wind sources and we find that the structure of the flow can be significantly different from that due to a uniform medium. We here present our results concerning the mass and angular momentum accretion rates and discuss how these may be used to set constraints on our Galaxy's central engine.

scholarly journals Radio Flare Activity of RS CVn Stars

1980 ◽  
Vol 88 ◽  
pp. 403-403
Author(s):  
Paul A. Feldman
Keyword(s):  
Binary Star ◽  
Quantitative Model ◽  
Magnetic Activity ◽  
Flare Activity ◽  
Radio Observatory ◽  
X Ray ◽  
Rs Cvn Stars ◽  
Solar Magnetic Activity ◽  
Radio Flare ◽  
Systematic Program

For several years, a systematic program to observe RS CVn and similar binaries has been undertaken with the 46-m telescope of the Algonquin Radio Observatory. A number of large radio outbursts at 2.8 cm wavelength has been found from HR 1099, AR Lac, SZ Psc, UX Ari, and HR 5110. In several cases, simultaneous, or nearly simultaneous, observations of these stars were made by cooperating observers at (other) radio, optical, UV, and X-ray wavelengths. It is now clearly established that the mechanism responsible for the cm-wavelength radio emission is nonthermal gyrosynchrotron radiation in a volume whose characteristic dimension is comparable with the binary star separation. More generally, a semi-quantitative model for the radio flare activity of these stars seems to be possible using greatly scaled-up analogues of solar magnetic activity.

LONGITUDINAL WAVES IN AN INHOMOGENEOUS MAGNETIC FIELD – PLASMA INTERFACE BASED ON THE WKB APPROXIMATION

1963 ◽  
Vol 41 (4) ◽  
pp. 569-580
Author(s):  
I. P. Shkarofsky
Keyword(s):  
Magnetic Field ◽  
Boundary Layer ◽  
Ion Beam ◽  
Inhomogeneous Magnetic Field ◽  
Wave Number ◽  
Plasma Region ◽  
Order Solution ◽  
Uniform Medium ◽  
Magnetic Field Region ◽  
Point To Point

Longitudinal perturbations are investigated which propagate in an inhomogeneous interface or transition boundary layer, from a plasma region where no magnetic field exists well within its interior, to a static magnetic field region from which the plasma is excluded. The inhomogeneity in this boundary layer is the prime inhomogeneity considered here. A WKB solution is obtained for waves whose wavelength is small compared with the equilibrium characteristic length. The component of the propagation wave number is assumed to vary in the direction in which the interface is inhomogeneous. From the zero-order solution it is shown that this wave number satisfies the same relation with the frequency of perturbation and velocities of the electron and ion beams, as that obtained in counter-streaming of an electron-plus-ion beam against another electron-plus-ion beam in a uniform medium. The first-order solution yields the manner in which the amplitude of the wave varies from point to point in the plasma interface. The physical significance of these modes and the time and space variation of these waves will be discussed. It is shown that the WKB solution is valid in the sheath up to quite small distances from the sheath boundary. Under certain conditions, a wave can exist which increases exponentially in time and whose amplitude increases towards the boundary. The problem of joining the WKB solution appropriately to a perturbed solution outside of the boundary is discussed.

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