Space Science

In the present investigation, we introduce an unified space-time fractional advection-dispersion equation involving Caputo time fractional derivative of order Riesz-Feller space fractional derivatives of order and asymmetry and of order and asymmetry . Then, we consider a Fourier series to obtain its solution involving Volterra integral equation. We also evaluate its numerical approximation formula and discuss some of its particular cases.

Universe is continuously expanding, and is observed to expand at a continuous increasing speed, much greater than that of light, though the theory of relativity destroys the relevance of this statement. This gave birth to a theory called Big Bang theory, which says universe was born from a single point, started from pure energy and then came matter, space, and time. Within a short time, it is said to have “fight” with anti-matter and a small part of total matter constructed this whole universe.

The aim of this paper is to examine the anomalous variations of the critical frequency (foF2), Total Electron content (TEC) and foEs parameters before earthquake occurred on 01 April 2014 Iquique Chile (M=8.2) and on 25 October 2013 Japan(M=7.1). Using the Correlation technique we analyzed the foF2, TEC and foEs parameters. A sudden drop in cross correlation coefficient of foF2 observed 02 days before, drop for TEC observed 12 days before and drop for foEs parameter observed 03 days before Chile event While drop in correlation coefficients for foF2 and foEs were observed 05 days and 01 day before Japan event.

The Sm3+doped Y2O3 phosphor has been prepared by using combustion technique. The visible frequency upconversion emission has been observed from the developed phosphor under excitation with a 980 nm diode laser excitation. The upconversion mechanism involved in the Sm3+ doped Y2O3 phosphor has been explained on the basis of excited state absorption (ESA) process.

We investigate dark energy models in an anisotropic Kantowski-Sachs space –time with a variable equation of state(EoS). The EoS for dark energy ? is found to be time dependent and its existing range for derive models is in good agreement with the recent observations. Under the suitable condition, the anisotropic models approach to isotropic scenario. We also find that during the evolution of the universe, the EoS parameter for DE changes from ?>-1 to ?=-1 in first model whereas from ?>-1 to ?<-1 in second model which is consistent with recent observations. The cosmological constant ? is found to be a positive decreasing function of time and it approaches a small positive value at late time (i.e. the present epoch) which is corroborated by results from recent supernovae Ia observations. The physical and geometric properties are also discussed.

Even though we have advanced tremendously in technology in the 21st century, we still have not been able to contact with any extraterrestrial civilizations. There have been many research and hypothesis on extraterrestrial civilizations such as The Drake Equation, The Fermi Paradox, Rare Earth Hypothesis. With the help of previous research and hypothesis on this subject by others, I have here tried to find out the possible reasons of not been able to contact with any extraterrestrial civilizations till now.

We have studied the impact of CMEs on the ionospheric critical frequency foF2 during the period 1996-2013. We have correlated the monthly maximum values of foF2 with monthly averages of CME’s energy, mass and speed; we found that the correlation coefficient R is 74%, 52% and 65% respectively. This indicates that the energetic, massive and fast CMEs can affect the ionospheric critical frequency foF2 more efficiently. In addition, the monthly average CME’s width correlates with the monthly maximum foF2 with R~57%. This implies that as the width of the CME increases, the possibility of this event to hit the Earth increases and the ionospheric-targeted area increases, thus the foF2 values; as an implication of increasing the ionization of the ionosphere; subsequently increases.

The Universe is globally hyperbolic as we did prove mathematically [S. A. Mabkhout, Phys. Essays 25, 112 (2012)]. The solution predicts the equation of state of cosmology ( P = -???? ). Penrose said if the curvature is not equal to zero, then inflation is out. The hyperbolic universe inflates exponentially produces an accelerated expansion of the universe without cosmological constant or scalar field, as we have shown [S. A. Mabkhout, Phys. Essays 26,422 (2013)]. “In testing the validity of any scientific paradigm, the key criterion is whether measurements agree with what is expected given the paradigm”1. The hyperbolic time evolution equation of the universe (the hyperbolic scale factor) fits the observed data and successfully predicts the Planck length (10-33 cm) at micro-cosmos scale as well as it predicts the current observed large structure (1028 cm) at macro-cosmos scale, thus connecting both General Relativity and Quantum Theory. The distance horizon in the flat universe is 14 Gpc. We found the distance horizon in the hyperbolic universe to be infinitely, thus solves the horizon problem. Although the perspective for nearby objects in hyperbolic space is very nearly identical to Euclidean space (i.e., the universe locally is approximately flat consistent with local observations, the apparent angular size of distant objects falls off much more rapidly, in fact exponentially. The universe is globally hyperbolic. Locally the spacetime is approximately flat, by means of the hyperbolic inflation. . Locally any deviations from flatness will be hyperbolically suppressed by the hyperbolic expansion of the scale factor, and the flatness problem is solved.

For over a decade now attention is critically focused on the exploitation of environmentally sustainable and renewable energy sources, particularly due to the depletable, expensive and pollution characteristics of fossil fuels. In this regard, solar energy has strong potentials to play a great future role, especially in the global areas around the equator. Substantial effort has therefore been made to cover numerous issues associated with harnessing solar power. Hargreaves equation and its derivatives as assessment models, wide range of literature studies documented across the globe with emphasis to African countries and the key green areas were substantially covered. Necessary recommendations were also offered in line with international energy demand and strategies.

By more than a decade, the contemplation on the velocity law took me as far as the human mind could inform of, where I wondered at that time; what is the relationship between all of the time, space and velocity?. This question was frequented my imagination impotent, whenever I tried to understand the extent of the relation between these two numbers: zero and one. The following questions are the source of inspiration: At first glance, may not seem to us that there is a relation between these questions and the velocity law, but if we tried to conduct a scientific investigation on the velocity law during a theory of the high credibility, we are surprised how the trick that brought to us by classical physics. I firmly believe that the answer of these questions will strongly solve the biggest enigma in our live. Let's see how we will be able to get the Mared (giant) out of its bottle, through this research.