Accretion onto Some Well-Known Regular Black Holes

In this work, we discuss the accretion onto static spherical symmetric regular black holes for specific choices of equation of state parameter. The underlying regular black holes are charged regular black hole using Fermi-Dirac Distribution, logistic distribution, nonlinear electrodynamics, respectively and Kehagias-Sftesos asymptotically flat regular black hole. We obtain the critical radius, critical speed and squared sound speed during the accretion process near the regular black holes. We also study the behavior of radial velocity, energy density and rate of change of mass for each regular black holes.Comment: 25 pages, 7 figures, Accepted for publication in Eur. Phys. J.

Effects of Thermal Fluctuations on Non-minimal Regular Magnetic Black Hole

We analyze the effects of thermal fluctuations on a regular black hole (RBH) of non-minimal Einstein-Yang-Mill theory with gauge field of magnetic Wu-Yang type and a cosmological constant. We consider the logarithmic corrected entropy in order to analyze the thermal fluctuations corresponding to non-minimal RBH thermodynamics. In this scenario, we develop various important thermodynamical quantities such as entropy, pressure, specific heats, Gibb's free energy and Helmothz free energy. We investigate first law of thermodynamics in the presence of logarithmic corrected entropy and non-minimal RBH. We also discuss the stability of this RBH using various frameworks such as $\gamma$ factor (comprises of ratio of heat capacities), phase transition, grand canonical ensemble and canonical ensemble. It is observed that the non-minimal RBH becomes more globally and locally stable if we increase the value of cosmological constant.Comment: 20 pages, 5 figure

Tidal Forces in Kiselev Black Hole

The aim of this paper is to examine the tidal forces occurred in Kiselev black hole surrounded by radiation and dust fluids. It is noted that radial and angular component of tidal force change the sign between event and Cauchy horizons. We solve the geodesic deviation equation for radially free falling bodies toward Kiselev black holes. We explain the geodesic deviation vector graphically and point out the location of event and Cauchy horizons in it for specific values of radiation and dust parameter.Comment: 20 pages, 10 figure

Thermodynamics of Black holes With Higher Order Corrected Entropy

For analyzing the thermodynamical behavior of two well-known black holes such as RN-AdS black hole with global monopole and $f(R)$ black hole, we consider the higher order logarithmic corrected entropy. We develop various thermodynamical properties such as, entropy, specific heats, pressure, Gibb's and Helmhotz free energies for both black holes in the presence of corrected entropy. The versatile study on the stability of black holes is being made by using various frameworks such as the ratio of heat capacities ($\gamma$), grand canonical and canonical ensembles, and phase transition in view of higher order logarithmic corrected entropy. It is observed that both black holes exhibit more stability (locally as well as globally) for growing values of cosmological constant and higher order correction terms.Comment: 23 pages, 10 figures, accepted for publication by Canadian Journal of Physics. arXiv admin note: text overlap with arXiv:1701.08650 by other author

Accreting Fluids onto Regular Black Holes Via Hamiltonian Approach

We investigate the accretion of test fluids onto regular black holes such as Kehagias-Sfetsos black hole and a regular black hole with Dagum Distribution Function. We analyze the accretion process when different test fluids are falling onto these regular black holes. The accreting fluid is being classified through equation of state according to features of regular black holes. The behavior of fluid flow and the existence of sonic points is being checked for these regular black holes. It is noted that three velocity depends on critical points and equation of state parameter on phase space.Comment: 25 pages; 10 Figure

Electrochemical and thermodynamic study on the corrosion performance of API X120 steel in 3.5% NaCl solution

The present work studied the effect of temperature on the corrosion behavior of API X120 steel in a saline solution saturated with CO2 in absence and presence of polyethyleneimine (PEI) as an environmentally safe green inhibitor. The effect of PEI on the corrosion behavior of API X120 steel was investigated using destructive and non-destructive electrochemical techniques. The overall results revealed that PEI significantly decreases the corrosion rate of API X120 steel with inhibition efficiency of 94% at a concentration of 100 μmol L−1. The adsorption isotherm, activation energy and the thermodynamic parameters were deduced from the electrochemical results. It is revealed that the adsorption of PEI on API X120 steel surface follows Langmuir adsorption isotherm adopting a Physi-chemisorption mechanism. Finally, the samples were characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques to elucidate the effect of aggressiveness of corrosive media on the surface morphology and the corrosion performance of API X120 steel. The surface topography result indicates that the API X120 steel interface in PEI presence is smoother than CO2 with Cl− ions or Cl− ions only. This is attributed to the compact protective film limits the aggressive ions transfer towards the metallic surface and reduces the corrosion rate. Moreover, PEI inhibition mechanism is based on its CO2 capturing ability and the PEI adsorption on the steel surface beside the siderite layer which give the PEI molecules the ability to reduce the scale formation and increase the corrosion protection due to capturing the CO2 from the brine solution

Sustainable Irrigation Management for Higher Yield

Sustainable irrigation is sensible application of watering to plants in agriculture, landscapes that aids in meeting current survival and welfare needs. Sustainable irrigation management can help with climate change adaptation, labor, energy savings, and the production of higher-value and yield of crops to achieve zero hunger in water-scarce world. To ensure equal access to water and environmental sustainability, investments in expanded and enhanced irrigation must be matched by improvements in water governance. Sustainable irrigation must be able to cope with water scarcity, and be resilient to other resource scarcities throughout time in context of energy and finance. The themes and SDGs related to clean water, water resources sustainability, sustainable water usage, agricultural and rural development are all intertwined in the concept of “sustainable irrigation for higher yield.” Sustainable irrigation management refers to the capability of using water in optimum quantity and quality on a local, regional, national, and global scale to meet the needs of humans and agro-ecosystems at present and in the future to sustain life, protect humans and biodiversity from natural and human-caused disasters which threaten life to exist. Resultantly higher yields will ensure food security

Some remarks on criticality and thermodynamics of the dynamic phantom AdS black holes

In this paper, we discuss the thermodynamic phase-transition, thermal stability and criticality of dynamic phantom AdS black hole (BH) in the presence of electric charge e and magnetic charge g. To accomplish this, we construct the specific heat and other important thermodynamical parameters which help us to investigate the stability and criticality. The thermodynamical properties of dynamic phantom AdS BH are examined by utilizing the specific heat $$(C_P)$$, volume expansivity $$(\beta )$$, isothermal compressibility $$(\kappa )$$, Temperature vs Entropy (T–S), Pressure vs Volume (P–V) and Gibbs free energy G, graphically. Specific heat against entropy describes the divergency behaviour, which produces the second-order phase transition. We also obtain isenthalpic curves for both systems in the T–P plane and determine the cooling and heating regions by utilizing Joule–Thomson expansion. Moreover, we discuss the behaviour of (P–V) isotherm that is equal to the liquid/gas transition of the Van-Der Waals fluid is exactly matched to 3/8 also known as a universal number. Furthermore, we investigate Swallow-tail behaviour and also discuss the stability and instability of the small black hole (SBH), Intermediate black hole (IBH) and large black hole (LBH)

Motion of spinning particles around dynamic phantom AdS black holes

This work is devoted to discussing spinning particles’ motion in the surrounding dynamic phantom AdS Black hole (BH) with phantom scalar field k. The primary goal of this research is to differentiate between the effects of electric and magnetic charges on dynamic phantom AdS BH. The study analyzes the dependence of the innermost stable circular orbit (ISCO), responsible for interactions between charged particles and the external magnetic field, and observes the circular orbits of particles revolving around the compact object. It is also observed that as electric and magnetic charges increase, the ISCO radius decreases. Additionally, stability of orbit, Keplerian frequency, and harmonic oscillations of charged particles are also discussed. We also find the condition, electric and magnetic charges of the dynamic phantom AdS BH effect the energy of the center of mass with magnetized, electrically charged, and neutral particles due to the collision. Lastly, we discuss the accretion process and obtain generalized equations for the speed of sound $$c^2_{s}$$ sec, 4-velocity u(r), energy density $$\rho (r)$$ and mass ($${\dot{M}}$$). We also plot these physical parameters against constant values of mass, electric and magnetic charges, and distinct values of state parameter $$\omega$$ to study the accretion process. We observe that radial velocity and energy density of the fluid remain positive and negative, and the rate of change of mass is increased and decreased for stiff, dust, quintessence, and phantom-like fluid, respectively