Rapidly rotating spheroids of polytropic index N = 1

1977 ◽  
Vol 211 ◽  
pp. 568 ◽  
Author(s):  
C. T. Cunningham
Keyword(s):  
Polytropic Index

Long-Term Variability of the Polytropic Index of Solar Wind Protons at 1 AU

Solar Physics ◽  
2013 ◽  
Vol 289 (4) ◽  
pp. 1371-1378 ◽  
Author(s):  
G. Nicolaou ◽  
G. Livadiotis ◽  
X. Moussas
Keyword(s):  
Solar Wind ◽  
Polytropic Index

scholarly journals Impact of generalized polytropic equation of state on charged anisotropic polytropes

2020 ◽  
Vol 80 (2) ◽  
Author(s):  
S. A. Mardan ◽  
M. Rehman ◽  
I. Noureen ◽  
R. N. Jamil
Keyword(s):  
Equation Of State ◽  
Speed Of Sound ◽  
Graphical Analysis ◽  
Maxwell Field ◽  
Anisotropic Fluid ◽  
Polytropic Index ◽  
Model Parameters ◽  
Field Equations ◽  
Polytropic Equation ◽  
Fluid Configuration

Abstract In this paper, generalized polytropic equation of state is used to get new classes of polytropic models from the solution of Einstein-Maxwell field equations for charged anisotropic fluid configuration. The models are developed for different values of polytropic index $$n=1,~\frac{1}{2},~2$$n=1,12,2. Masses and radii of eight different stars have been regained with the help of developed models. The speed of sound technique and graphical analysis of model parameters is used for the viability of developed models. The analysis of models indicates they are well behaved and physically viable.

Experimental study of the polytropic index of the compression stroke for a direct injection hydrogen engine

2020 ◽  
Vol 45 (52) ◽  
pp. 28196-28203
Author(s):  
Ling-Zhi Bao ◽  
Bai-Gang Sun ◽  
Qing-He Luo ◽  
Xi Wang ◽  
Qing-Yu Niu
Keyword(s):  
Experimental Study ◽  
Direct Injection ◽  
Polytropic Index ◽  
Compression Stroke

scholarly journals Dynamics of general barotropic stellar fluid in the framework of R + 2αT gravity

2020 ◽  
Vol 35 (12) ◽  
pp. 2050089
Author(s):  
Karim Mosani ◽  
Gauranga C. Samanta
Keyword(s):  
Apparent Horizon ◽  
Initial Density ◽  
Type Equation ◽  
Matter Field ◽  
Scale Factor ◽  
Cosmic Acceleration ◽  
Energy Conditions ◽  
Index Formula ◽  
Polytropic Index ◽  
Barotropic Fluid

Gravitational collapse of a spherically symmetric homogeneous perfect barotropic fluid with linear as well as polytropic-type Equation of State (EoS) has been investigated in the framework of a linear model of [Formula: see text] gravity. This modified gravity has the potential to explain the observed cosmic acceleration. The calculations have been done taking the transformed time coordinate [Formula: see text], where [Formula: see text] is the initial density of the fluid. For linear EoS [Formula: see text], the condition for being a true singularity, along with sufficient condition for the formation of apparent horizon covering the singularity has been derived. For a polytrope having the EoS [Formula: see text], the scale factor [Formula: see text] as a function of fluid density [Formula: see text] has been obtained which is then used to study the dynamics of the fluid. Role of the polytropic index [Formula: see text] and the constant of proportionality [Formula: see text] in the dynamics of the fluid is also studied. A new type of exotic matter field having varied dependence of scale factor on the density, and having the potential to give rise to bouncing cosmology, provided it is the dominating fluid in the universe, is obtained in this domain and is investigated. Energy conditions are discussed.

Analysis of Screw-Expander Performance

1989 ◽  
Vol 203 (1) ◽  
pp. 15-20 ◽  
Author(s):  
K C Ng ◽  
T B Lim ◽  
T Y Bong
Keyword(s):  
Experimental Data ◽  
Experimental Work ◽  
Empirical Model ◽  
Saturated Steam ◽  
Polytropic Index ◽  
Work Output ◽  
Predicted Values ◽  
Good Agreement ◽  
Thermodynamic Processes

The paper examines the thermodynamic processes of a helical screw-expander that operates with dry saturated steam at its inlet. The work output of the screw-expander is analysed using a simple ‘pseudo-polytropic’ index. Using the available experimental data from the literature, an empirical model for the prediction of work using the ‘pseudo-polytropic’ indices is formulated. The expansion indices are expressed in terms of built-in volumetric and pressure ratios; how they are formulated is usually given in an expander specification. Based on the empirical model, there is a good agreement between the experimental work and the predicted values.

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