Bijan Nikouravan

IPS, IAU & UM · Physics Astro

This research focuses on the classification and properties of G-Type main sequence stars. It discusses the historical ‎‎development of star classification systems and their importance in understanding stellar evolution, composition, ‎and galactic ‎structures. The paper also examines the mass-radius and mass-luminosity relationships of stars, ‎highl...

Lagrangian method applied as well as tensor method, for a linear transformed geodesic line element of Schwarzschild-like The ‎Lagrangian method was applied for a linearly transformed geodesic line element of a Schwarzschild-like solution instead of ‎the tensor method. The solution shows that it is not only valid for spherical objects but also it is...

Lagrangian method applied as well as tensor method, for a linear transformed geodesic line element of Schwarzschild-like The ‎Lagrangian method was applied for a linearly transformed geodesic line element of a Schwarzschild-like solution instead of ‎the tensor method. The solution shows that it is not only valid for spherical objects but also it is...

HD 158259 (or HIP 85268) is one of the members of the main sequence in G0 group stars located approximately at 88 ‎light-‎years away in the constellation Draco, discussed with respect to the solar system. HD 158259 was discovered by the ‎SOPHIE ‎échelle spectrograph using the radial velocity method. This system includes five confirmed planets orbit...

In 2015, after the discovery of Kepler-186f, the fifth exoplanet in orbit of its star, Kepler-186, we investigated for three new undetected planets in the Kepler-186 system [1]. Of the planets which are owned by the Kepler-186, the first Earth-like planet and far from its star is Kepler-186f. Considering the order of these five discovered planets,...

The discovery of extrasolar planets outside our solar system and around other stars is now well underway. In the presented paper, calculations of some physical properties for confirmed exoplanets have been done. We have estimated physical properties such as the semi-major axis for potentially habitable exoplanets, the mass of planets by applying Ke...

The Von Neumann entropy plays a central role in the quantum information theory and is a concave function and following the property 0< ∑𝑆(𝜆𝑖𝜌𝑖)𝑖∈1−∑𝜆𝑖𝑆(𝜌𝑖)𝑖∈1≤−∑𝜆𝑖(log 𝜆𝑖)𝑖∈1 . In this paper, we introduce a new proof for the linearity of Von Neumann entropy in the rate without using the above inequality. Here the Von Neumann entropy is concave; tha...

Accurate quantification of naturally occurring radioactive materials in soil provides information on geological characteristics, possibility of petroleum and mineral exploration, radiation hazards to the dwelling populace etc. Of practical significance, the earth surface media (soil, sand and sediment) collected from the densely populated coastal a...

A recent experiment was achieved at HAARP to study the scaling of the ionospherically generated ELF signal with power transmitted from the high frequency (HF) array. The results were in excellent agreement with computer simulations. The outcomes approving that the ELF power increases with the square of the incident HF power. This paper present a re...

Modified Newtonian Dynamics (MOND) is a theory that suggests a modification in Newtonian dynamics. It is an empirically motivated modification of Newtonian gravity without the need of dark matter. This theory is well fitted by explaining why the velocity of galaxies or stars are in linear and in flat curve. More than 84 galaxies are in a well fitti...

The chemistry of the gamma aminobutyric acid (GABA) had been established. However, the explanation on the interplay between GABA receptors antagonize fundamental concept of the GABAergic signaling. For example, glutamate spillover from excitatory afferent terminals leads to the modulation of GABAergic signals. However, this result is true with resp...

The dynamics of infectious diseases are dependent on salient environment and climate factors which are directly proportional to its transmission. Malaria is a common disease of typical tropics of the West African sub-region. The influences of malaria transmission via meteorological and environmental parameters were examined. Remotely sensed paramet...

In this paper we have investigated for Three New undetected planets in Kepler-186 system. In 2014 the fifth Exoplanet Kepler-‎‎186f, discovered in orbit of its ‎star, Kepler-‎‎186. All planets in this system are in the range of ‎Earth's size. Of these planets which are owned ‎by the Kepler-186, ‎the first Earth-like planet and far from its ‎star is...

The mechanism of the femtosecond spin dynamics is still not properly understood. The remodeled Bloch-Schrödinger equation was incorporated into the Hamiltonian. The mechanism of the femtosecond dynamics was investigated under three quantum states. The spin relaxation mechanism operated in a single continuous time scale (>70ps) which was in variance...

Friedmann equations are used to describe the evolution of the universe. Solving Friedmann equations for the scale factor indicates that the universe starts from an initial singularity where all the physical laws break down. However, the Friedmann equations are well describing the late-time or large scale universe. Hence now, many physicists try to...

Newton considered three-dimensional universe endowed with flat space Euclidean geometry, and treated the time as an outside parameter and established his dynamics of the universe. Einstein along with space, considered time, and generated a four-dimensional universe endowed with non-Euclidean curved space-time geometry with time as its fourth dimens...

In this paper, a three-stage fifth-order Runge-Kutta method for the integration of a special third-order ordinary differential equation (ODE) is constructed. The zero stability of the method is proven. The numerical study of a third-order ODE arising in thin film flow of viscous fluid in physics is discussed. The mathematical model of thin film flo...

It has been seen that the period of solar activity and its cycle has a decrease of seismic activity in the compression zone of the Earth. In addition, at the same time there is an increase of the activity in the tension zones of the Earth. This study has been emphasized on last 45 years (i.e. 1960-2005) cyclic data in term of the number of seismic...

In this paper, a three-stage fifth-order Runge-Kutta method for the integration of a special third-order ordinary differential equation (ODE) is constructed. The zero stability of the method is proven. The numerical study of a third-order ODE arising in thin film flow of viscous fluid in physics is discussed. The mathematical model of thin film flo...

A simple geometrical model considered to calculate redshift values of 378 celestial objects such as Galaxies ‎and Quasi stellar objects(QSO). In this model, Earth as a small point selected as centre of observation. This ‎constructed model, is based on the angle of observation from Earth. Although, theoretical and experimental ‎results of this model...

We study the evaluation of bending of light ray passing near a massive elliptical galaxy or star. To obtain this solution we used two different, Einsteinian and Lagrangian method. In doing this, we consider and compare the difference deflection angle between spherical and elliptical shape objects which led to appear a small but not negligible coeff...

Abstract. Friedmann equations are used to describe the evolution of the universe. Solving Friedmann equations for the scale factor indicates that the universe starts from an initial singularity where all the physical laws break down. However, the Friedmann equations are well describing the late-time or large scale universe. Hence now, many physicis...

We derived Reissner-Nordstrom solution for non-rotating charged celestial objects with Elliptical in shaped, such as stars and/or elliptical galaxies. This metric is capable to describing the behavior of gravitational field outside any charged ellipsoidal celestial objects like stars, galaxies or Quasi-stellar object.

A simple geometrical model considered to calculate redshift values of 378 celestial objects such as Galaxies and Quasi stellar objects(QSO). In this model, Earth as a small point located in the centre of theoretical observation. This constructed model, is based on the angle of observation from Earth. Although, theoretical and experimental results o...

The general solution of a static sphere of perfect fluid of uniform density using isotropic line element has been obtained by using the additional condition of continuity at the boundary 𝑟=𝑎. Here it is shown that, this solution is a solution of equation of Wyman with an additional integrating constant. If we do not put the condition of continuity...

The general solution of a static sphere of perfect fluid of uniform density using isotropic line element has been obtained by using the additional condition of continuity at the boundary. Here it is shown that, this solution is a solution of equation of Wyman with an additional integrating constant. If we do not put the condition of continuity at t...

The relationships between solar activities (sunspots, solar 10.7cm radio flux, solar irradiance, and solar proton events) and local earthquakes investigated in this paper. The geographical location of study is New Zealand area. All earthquakes data have been chosen for , from first of 1970 to Jun 2012. The study reveals the following conclusions: 1...

Einstein's field equations are based on Riemannian geometry. One of the great important in Riemannian geometry is the curves that minimize the distance between two given points. The Ricci curvature tensors are also broadly applicable to modern Riemannian geometry and general theory of relativity (GTR). The solution of Einstein's field equations, ne...

Considering effects of tidal plus centrifugal stress acting on icy-rocks and the tensile strength thereof, icy-rocks being in the density range (1–2.4) g cm-3 which had come into existence as collisional ejecta (debris) in the vicinity of Pluto at the time when Pluto-Charon system came into being as a result of a giant impact of a Kuiper Belt Objec...

The accuracy of the measured excitation functions of nuclear reactions largely depend on the precise measurements of the exposed beam energy in activation experiment. We investigated the proton beam energy of the MC-50 cyclotron at the Korea Institute of Radiological and Medical Sciences (KIRAMS) employing the method natCu(p,xn)62Zn / natCu(p,xn)65...

The simplest solution of Einstein's field equations is Schwarzschild solution. This solution is not able to describe for any nonspherical shaped objects. Some stars and galaxies are in ellipsoidal. Consequently, the gravitational field around these objects should be different in compare with spherical form. This paper is considering a new line elem...

Schwarzschild solution is the simplest solution of Einstein's field equations, but it has not been able to describe any non-spherical in shape as in the real are existing. Many objects like stars and/or galaxies are in the form of ellipsoidal form and consequently, the gravitational lines around the objects are different in comparing with spherical...

The cosmic (physical) vacuum according to modern data possesses the properties of a material medium. In combination with the celestial bodies, this medium is capable of forming dynamic structures. Presumably, these structures have a wave nature, and in their development, the gravitational waves, emitted by the stars and their planetary systems can...

Approximate Kerr- like interior and exterior solutions for a very slowly rotating star of perfect fluid is presented here which is valid for a very slowly rotating and hence very slightly oblate star of perfect fluid rotating with a very small constant angular velocity. Corresponding approximate exterior metric represents approximate Kerr exterior...

Sun as the largest and massive object has taking 99.9% of the total mass of our solar system. The primary source of radiant energy to Earth is solar radiation. Solar energy with a wide spectrum of wavelengths reaches the atmosphere of Earth. It also includes high energy particles and charged particles. The effects of these radiations and cosmic par...

In this paper, we construct a new form of a line element exactly in ellipsoidal coordinate system. Einstein field equations are based on Riemannian geometry. The Ricci curvature tensors are also broadly applicable to modern Riemannian geometry and general theory of relativity too. For solution of Einstein field equations, Ricci tensors are very ess...

For more effective use of ground fresh water resources, a remote sensing and GIS have been used in many places in last decades. The digital topographic maps in scale 1:25000 within GIS environment have been studied to observe the risk reduction and changing of the water resources because of the tectonic activities which are crucial to generate a gr...

In solution of Einstein field equations it is necessary to contracting Riemann-Christofell tensor. The contraction of Riemann-Christofell tensor or simply the curvature tensor is called the Ricci tensor and denoted by . The calculation of Ricci tensor in 3 and especially in 4-dimension is not very difficult but, it is very tedious; and need more ti...

Evaluation of the earthquakes risk and mitigation strategy is one of the crucial and concerned matters for a country where disasters may occur such as Bam earthquake in Iran. Tectonic and structural geologic study using the modern space-based remote sensing and integrates to the spatial data in Geographic Information System (GIS) environment has be...

Geographical information system (GIS) is becoming increasingly used for the sciences. GIS are computerized systems for the storage, retrieval, manipulation, analysis, and display geographically referenced data. The space information to develop a space GIS for datasets is one of the parameters to analyze and map the celestial objects at a glance. Th...