• Volume 82, Issue 3

March 2014,   pages  463-607 and L609-L615

• General editorial on publication ethics

• Solitons and periodic solutions to a couple of fractional nonlinear evolution equations

This paper studies a couple of fractional nonlinear evolution equations using first integral method. These evolution equations are foam drainage equation and Klein–Gordon equation (KGE), the latter of which is considered in (2 + 1) dimensions. For the fractional evolution, the Jumarie’s modified Riemann–Liouville derivative is considered. Exact solutions to these equations are obtained.

• Einstein–Podolski–Rosen paradox, non-commuting operator, complete wavefunction and entanglement

Einstein, Podolski and Rosen (EPR) have shown that any wavefunction (subject to the Schrödinger equation) can describe the physical reality completely, and any two observables associated with two non-commuting operators can have simultaneous reality. In contrast, quantum theory claims that the wavefunction can capture the physical reality completely, and the physical quantities associated with two non-commuting operators cannot have simultaneous reality. The above contradiction is known as the EPR paradox. Here, we unambiguously expose that there is a hidden assumption made by EPR, which gives rise to this famous paradox. Putting the assumption right this time leads us not to the paradox, but only reinforces the correctness of the quantum theory. However, it is shown here that the entanglement phenomenon between two physically separated particles (they were entangled prior to separation) can only be proven to exist with a `proper’ measurement.

• Finite-time synchronization of a class of autonomous chaotic systems

Some criteria for achieving the finite-time synchronization of a class of autonomous chaotic systems are derived by the finite-time stability theory and Gerschgorin disc theorem. Numerical simulations are shown to illustrate the effectiveness of the proposed method.

• Synchronization of general complex networks via adaptive control schemes

In this paper, the synchronization problem of general complex networks is investigated by using adaptive control schemes. Time-delay coupling, derivative coupling, nonlinear coupling etc. exist universally in real-world complex networks. The adaptive synchronization scheme is designed for the complex network with multiple class of coupling terms. A criterion guaranteeing synchronization of such complex networks is established by employing the Lyapunov stability theorem and adaptive control schemes. Finally, an illustrative example with numerical simulation is given to show the feasibility and efficiency of theoretical results.

• Impact of density-dependent symmetry energy and Coulomb interactions on the evolution of intermediate mass fragments

Within the framework of isospin-dependent quantum molecular dynamics (IQMD) model, we demonstrate the evolution of intermediate mass fragments in heavy-ion collisions. In this paper, we study the time evolution, impact parameter, and excitation energy dependence of IMF production for the different forms of density-dependent symmetry energy. The IMF production and charge distribution show a minor but considerable sensitivity towards various forms of densitydependent symmetry energy. The Coulomb interactions affect the IMF production significantly at peripheral collisions. The IMF production increases with the stiffness of symmetry energy.

• Step index fibre using laser interferometer

model is suggested to describe the fringe shift which occurs due to the phase variations of cladded glass fibre introduced between the two plates of the liquid wedge interferometer illuminated with a He–Ne laser. The fringe shift of the phase object which appears in the denominator of the Airy distribution formula of the multiple beam interference is represented in the harmonic term. An experiment is conducted using liquid wedge interferometer where the step index glass fibre of a nearly quadratic thickness variation is introduced between the two plates of the interferometer. The obtained fringe shift shows a good agreement with the proposed quadratic model. The Matlab code is written to plot the interferometer fringes comprising the shift of the step index fibre. Secondly, recognition of elliptical fibres is outlined using tomographic imaging. Finally, results and concluding remarks are given.

• Synthesis and characterization of gel-grown cobalt tartrate crystals

Crystals of cobalt tartrate are grown from the gel using chemical reaction method. The functional groups are found from Fourier transform infrared spectroscopy (FTIR). The OH stretching mode owing to water, carbonyl group, CH stretching modes and metal–oxygen stretching are identified. The unit cell dimensions, interaxial angles and unit cell volume are found from powder X-ray diffraction studies (XRD) which show the orthorhombic nature of the crystal. The magnetic study is used to find the magnetic susceptibility and magnetic moment of the grown crystal. It reveals the magnetic nature of the crystal. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) are done to find the thermal properties of the crystal which manifest the water of hydration in the crystal. The variation of dielectric constant with respect to the applied frequency shows the polarization property of the crystal. The AC conductivity is increased proportionally with increase in frequency. The reverse nature is found for the AC resistivity. The nature of the composition of the crystals affects the dielectric properties.

• A new temperature-dependent equation of state of solids

In the present paper, a temperature-dependent equation of state (EOS) of solids is discussed which is found to be applicable in high-pressure and high-temperature range. Present equation of state has been applied in 18 solids. The calculated data are found in very good agreement with the data available from other sources.

• Calculation of growth per cycle (GPC) of atomic layer deposited aluminium oxide nanolayers and dependence of GPC on surface OH concentration

In this paper a theoretical calculation is presented for the growth per cycle (GPC) of the film and the variation of GPC with OH concentration on the substrate surface. The calculated GPC range (0.179 nm–0.075 nm) agrees well with reported experimental values. The present approach yielded a density of 2.95 g/cc for the deposited films. The number of monolayers (ML) as a function of the OH concentration on the substrate surface is calculated and is found to be in the range of 58.4–24.2% of the total number of cycles of deposition. Effective monolayer thickness is calculated as 0.31 nm.

• Predicting the growth of new links by new preferential attachment similarity indices

By revisiting the preferential attachment (PA) mechanism for generating a classical scale-free network, we propose a class of novel preferential attachment similarity indices for predicting future links in evolving networks. Extensive experiments on 14 real-life networks show that these new indices can provide more accurate prediction than the traditional one. Due to the improved prediction accuracy and low computational complexity, these proposed preferential attachment indices can be helpful for providing both instructions for mining unknown links and new insights to understand the underlying mechanisms that drive the network evolution.

• Long term performance evaluation of the TACTIC imaging telescope using ∼400 h Crab Nebula observation during 2003–2010

The TeV atmospheric Cherenkov telescope with imaging camera (TACTIC) 𝛾-ray telescope has been in operation at Mt. Abu, India since 2001 to study TeV 𝛾-ray emission from celestial sources. During the last 10 years, apart from consistently detecting a steady signal from the Crab Nebula above ∼1.2 TeV energy, at a sensitivity level of ∼5.0𝜎 in ∼25 h, the telescope has also detected flaring activity from Mrk 421 and Mrk 501 on several occasions. Although we used Crab Nebula data partially, in some of the reported results, primarily for testing the validity of the full data analysis chain, the main aim of this work is to study the long term performance of the TACTIC telescope by using consolidated data collected between 2003 and 2010. The total on-source data, comprising ∼402 h, yields an excess of ∼(3742±192) 𝛾-ray events with a statistical significance of ∼19.9𝜎 . The off-source data, comprising ∼107 h of observation, is found to be consistent with a no-emission hypothesis, as expected. The resulting 𝛾-ray rate for the onsource data is determined to be ∼(9.31±0.48) h-1. A power law fit (d𝛷/d𝐸 = $f_0E^{−\Gamma}$) with $f_0 \tilde (2.66 \pm 0.29) \times 10^{−11}$ cm-2 s-1 TeV-1 and $\Gamma \tilde$ 2.56 ± 0.10 is found to provide reasonable fit to the inferred differential spectrum within statistical uncertainties. The spectrum matches reasonably well with that obtained by other groups. A brief summary of the improvements in the various subsystems of the telescope carried out recently, which has resulted in a substantial improvement in its detection sensitivity (viz., ∼5𝜎 in an observation period of ∼13 h as compared to ∼25 h earlier) are also presented in this paper. Encouraged by the detection of strong 𝛾-ray signals from Mrk 501 and Mrk 421 on several occasions, there is considerable scope for the TACTIC telescope to monitor similar TeV 𝛾-ray emission activity from other active galactic nuclei on a long-term basis.

• Erratum to: Boson bound states in the 𝛽-Fermi–Pasta–Ulam model

• Anomalous Kolar events revisited: Dark matter?

The possibility of the unexplained Kolar events, recorded in the 1970s and 1980s, being due to the decays of dark matter particles of mass in the range of 5–10 GeV, is pointed out.

• # Pramana – Journal of Physics

Volume 94, 2020
All articles
Continuous Article Publishing mode

• # Editorial Note on Continuous Article Publication

Posted on July 25, 2019