Tolman mass of spherical fluids with electromagnetic field

2019 ◽  
Vol 34 (02) ◽  
pp. 1950012 ◽  
Author(s):  
M. Z. Bhatti ◽  
Z. Yousaf ◽  
A. Yousaf
Keyword(s):  
Gravitational Collapse ◽  
Mass Function ◽  
Physical Factors ◽  
Field Equations ◽  
Density Inhomogeneity ◽  
Local Anisotropy ◽  
Anisotropic Matter ◽  
Weyl Curvature Tensor ◽  
The Impact

Assuming a system with spherical symmetry in f(R) gravity filled with dissipative charged and anisotropic matter, we study the impact of density inhomogeneity and local anisotropy on the gravitational collapse in the presence of charge. For this purpose, we evaluated the modified Maxwell field equations, Weyl curvature tensor, and the mass function. Using Misner–Sharp mass formalism, we construct a relation between the Weyl tensor, density inhomogeneity, and local anisotropy. Specifically, we obtain the expression of modified Tolman mass which helps to analyze the influence of charge and dark source terms on different physical factors, also it helps to study the role of these factors on gravitational collapse.

Influence of f(G) gravity on the complexity of relativistic self-gravitating fluids

2021 ◽  
pp. 2150097
Author(s):  
M. Z. Bhatti ◽  
Z. Yousaf ◽  
S. Khan
Keyword(s):  
Degrees Of Freedom ◽  
Mass Function ◽  
Anisotropic Pressure ◽  
Riemann Curvature Tensor ◽  
Density Inhomogeneity ◽  
Anisotropic Matter ◽  
Energy Density Inhomogeneity ◽  
Symmetric Structures ◽  
The Impact ◽  
Fluid Configuration

In this paper, we extend the notion of complexity for the case of nonstatic self-gravitating spherically symmetric structures within the background of modified Gauss–Bonnet gravity (i.e. [Formula: see text] gravity), where [Formula: see text] denotes the Gauss–Bonnet scalar term. In this regard, we have formulated the equations of gravity as well as the relations for the mass function for anisotropic matter configuration. The Riemann curvature tensor is broken down orthogonally through Bel’s procedure to compose some modified scalar functions and formulate the complexity factor with the help of one of the scalar functions. The CF (i.e. complexity factor) comprehends specific physical variables of the fluid configuration including energy density inhomogeneity and anisotropic pressure along with [Formula: see text] degrees of freedom. Moreover, the impact of the dark source terms of [Formula: see text] gravity on the system is analyzed which revealed that the complexity of the fluid configuration is increased due to the modified terms.

Dissipative planar gravitational collapse in f(G) gravity

2014 ◽  
Vol 29 (13) ◽  
pp. 1450068 ◽  
Author(s):  
M. Sharif ◽  
Ayesha Ikram
Keyword(s):  
Gravitational Collapse ◽  
Gravitational Force ◽  
Field Equations ◽  
Density Inhomogeneity ◽  
Isotropic Source ◽  
Plane Symmetric ◽  
Energy Density Inhomogeneity ◽  
The Impact ◽  
The Relationship ◽  
Physical Quantities

This paper is devoted to analyze the dynamics of plane symmetric gravitational collapse as well as energy density inhomogeneity in f(G) gravity. The field equations are constructed for dissipative isotropic source and Darmois junction conditions are used to discuss the process of collapse. We use Misner–Sharp mechanism to develop dynamical equation and couple it with transport equation to explore the impact of gravitational force on the collapsing rate. For constant f(G) model, we conclude that the rate of collapse slows down. Finally, we discuss the relationship between the Weyl tensor and physical quantities.

On Approaches to Taking into Account the Risks of Changing Climatic Conditions when Planning and Implementing Oil and Gas Projects

2021 ◽  
Vol 18 (1) ◽  
pp. 52-65
Author(s):  
P. N. Mikheev
Keyword(s):  
Climate Change ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Climatic Conditions ◽  
Qualitative Assessment ◽  
Physical Factors ◽  
Gas Industry ◽  
Climate Risks ◽  
The Impact

The article discusses issues related to the impact of climate change on the objects of the oil and gas industry. The main trends in climate change on a global and regional (on the territory of Russian Federation) scale are outlined. Possible approaches to the identification and assessment of climate risks are discussed. The role of climatic risks as physical factors at various stages of development and implementation of oil and gas projects is shown. Based on the example of oil and gas facilities in the Tomsk region, a qualitative assessment of the level of potential risk from a weather and climatic perspective is given. Approaches to creating a risk management and adaptation system to climate change are presented.

scholarly journals A new class of relativistic model of compact stars of embedding class I

2017 ◽  
Vol 26 (09) ◽  
pp. 1750090 ◽  
Author(s):  
Piyali Bhar ◽  
Ksh. Newton Singh ◽  
Tuhina Manna
Keyword(s):  
Compact Star ◽  
Mass Function ◽  
Static Stability ◽  
Compact Stars ◽  
Stable Region ◽  
Energy Conditions ◽  
Arbitrary Form ◽  
Star Model ◽  
Field Equations ◽  
Anisotropic Matter

In the present paper, we have constructed a new relativistic anisotropic compact star model having a spherically symmetric metric of embedding class one. Here we have assumed an arbitrary form of metric function [Formula: see text] and solved the Einstein’s relativistic field equations with the help of Karmarkar condition for an anisotropic matter distribution. The physical properties of our model such as pressure, density, mass function, surface red-shift, gravitational redshift are investigated and the stability of the stellar configuration is discussed in details. Our model is free from central singularities and satisfies all energy conditions. The model we present here satisfy the static stability criterion, i.e. [Formula: see text] for [Formula: see text][Formula: see text]g/cm3(stable region) and for [Formula: see text][Formula: see text]g/cm3, the region is unstable i.e. [Formula: see text].

Models of non-static and inhomogeneous gravitating source in Rastall gravity

2021 ◽  
Vol 18 (03) ◽  
pp. 2150042
Author(s):  
G. Abbas ◽  
M. Tahir ◽  
M. R. Shahzad
Keyword(s):  
Gravitational Collapse ◽  
Mass Function ◽  
Energy Conditions ◽  
Parametric Form ◽  
Field Equations ◽  
Expansion Formula ◽  
Spherical Source ◽  
Expansion Scalar ◽  
Theory Of Gravity ◽  
Trapped Surface

In this paper, we have explored the non-static anisotropic gravitational collapse and expansion solutions in Rastall theory of gravity. The field equations have been formulated for the non-static and inhomogeneous gravitating source. The Misner–Sharp mass function, auxiliary solution and trapped condition have been used to obtained a trapped surface. The auxiliary solutions have been used to obtain the expansion and collapse solutions; these solutions depend on [Formula: see text] and parameter [Formula: see text] (which appears due to parametric form of metric components); also the range of parameter [Formula: see text] has been examined. The expansion scalar [Formula: see text] depends on parameter [Formula: see text], in the case of expansion [Formula: see text] for [Formula: see text], while for collapse [Formula: see text] with [Formula: see text]. Also, the dynamics of the gravitating spherical source has been discussed graphically with the effects of Rastall parameter [Formula: see text]. For the physically reasonable fluid, the validity of energy conditions has been discussed for expansion and collapse solutions with the various values of [Formula: see text].

scholarly journals On the role of density inhomogeneity and local anisotropy in the fate of spherical collapse

1998 ◽  
Vol 237 (3) ◽  
pp. 113-118 ◽  
Author(s):  
L Herrera ◽  
A Di Prisco ◽  
J.L Hernández-Pastora ◽  
N.O Santos
Keyword(s):  
Density Inhomogeneity ◽  
Local Anisotropy ◽  
Spherical Collapse

scholarly journals Intraluminal Impact of Food: New Insights from MRI

Nutrients ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 1147 ◽  
Author(s):  
Robin Spiller ◽  
Luca Marciani
Keyword(s):  
Small Bowel ◽  
Gastric Secretion ◽  
Water Content ◽  
Physical Factors ◽  
Non Invasive ◽  
Health And Disease ◽  
The Impact ◽  
Osmotic Effects ◽  
Serial Evaluation

Understanding how the gut responds to food has always been limited by the available investigatory techniques. Previous methods involving intubation and aspiration are largely limited to liquid-only meals. The aim of this review is to describe how MRI has allowed analysis of the processing of complex multiphase meals. This has demonstrated the role of physical factors such as viscosity, fat and fibre content in controlling gastric secretion and motility. It has also allowed the description of changes induced in small bowel water content and the role of osmotic effects of poorly absorbed carbohydrates such as fructose, sorbitol and mannitol. Intestinal secretions can be shown to be stimulated by a range of fruit and vegetables and the effect of this on colonic water content can also be measured. This has been used to demonstrate the mode of action of commonly used laxatives including bran and psyllium. The wealth of data which can be obtained together with its non-invasive nature and safety makes the technique ideal for the serial evaluation of the impact of different nutrients and drugs in both health and disease.

Energy content of a collapsing sphere with f(R) gravity

2019 ◽  
Vol 16 (03) ◽  
pp. 1950041 ◽  
Author(s):  
M. Zaeem-ul-Haq Bhatti ◽  
Z. Yousaf ◽  
A. Yousaf
Keyword(s):  
Energy Content ◽  
Mass Function ◽  
Systematic Investigation ◽  
Anisotropic Pressure ◽  
Field Equations ◽  
Density Inhomogeneity ◽  
Dynamical Equations ◽  
Spherical System ◽  
Modified Gravity Theory ◽  
Sphere Radius

This paper deals with the exploration of collapse rate and Tolman mass function for spherical system under the influence of [Formula: see text] modified gravity theory after using Herrera technique. We have taken the matter configuration to be anisotropic as well as dissipative due to diffusion and streaming out radiations. The modified field equations and dynamical equations are explored for a systematic investigation of Tolman mass. An explicit link among the matter profile, Weyl tensor and mass function is exhibited in this scenario. We found that the anisotropic pressure and density inhomogeneity tends to increase the Tolman mass within the sphere radius, while [Formula: see text] terms stabilize the system.

Intergroup Threat and Outgroup Attitudes

2013 ◽  
Vol 44 (5) ◽  
pp. 311-319 ◽  
Author(s):  
Marco Brambilla ◽  
David A. Butz
Keyword(s):  
Gay Men ◽  
Social Group ◽  
Welfare Recipients ◽  
Intergroup Attitudes ◽  
Social Policies ◽  
Intergroup Threat ◽  
Economic Threat ◽  
The Impact ◽  
General Climate

Two studies examined the impact of macrolevel symbolic threat on intergroup attitudes. In Study 1 (N = 71), participants exposed to a macrosymbolic threat (vs. nonsymbolic threat and neutral topic) reported less support toward social policies concerning gay men, an outgroup whose stereotypes implies a threat to values, but not toward welfare recipients, a social group whose stereotypes do not imply a threat to values. Study 2 (N = 78) showed that, whereas macrolevel symbolic threat led to less favorable attitudes toward gay men, macroeconomic threat led to less favorable attitudes toward Asians, an outgroup whose stereotypes imply an economic threat. These findings are discussed in terms of their implications for understanding the role of a general climate of threat in shaping intergroup attitudes.

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