001337   GUGAPRIYA G, RAJAGOPAL K, KARTHIKEYAN A, LAKSHMI B (Vellore Institute of Technology, Chennai - 600 127, Email: lakshmi.b@vit.ac.in) : A family of conservative chaotic systems with cyclic symmetry. Pramana – J Phys 2019, 92(4), 48.

In this paper, we propose a family of circulant systems with conservative property. Various dynamical properties of the circulant systems are derived and investigated. Bifurcation plots are derived and presented for a system and the Lyapunov exponents are derived to show the existence of chaotic oscillations, and their sum being zero confirms the conservativeness for certain values of parameters. One of the proposed systems is then implemented in field programmable gate array (FPGA) to show the hardware reliability. We used the hardware–software cosimulation to see the phase portraits of the FPGA implemented system. The discrete integrators required for solving the initial value problem are implemented using the Euler’s method. The register transfer level schematics of the FPGA implemented system and the resources used for the implementations are presented.

5 illus, 3 tables, 44 ref

001369   SINGH A, JAIN S R (Nuclear Physics Div, Bhabha Atomic Research Centre, Mumbai - 400 085, Email: srjain@barc.gov.in) : A PT - symmetric simple harmonic oscillator. Pramana – J Phys 2019, 92(4), 47.

We consider a simple harmonic oscillator with non-Hermitian term and study it classically and quantum mechanically. We conclude that this version of oscillator, which breaks parity and time reversal, displays all the features possessed by the usual harmonic oscillator. In particular, we calculate its spectrum, adiabatic invariance and Wigner functions, and show that there is a consistency between the classical and quantum descriptions.

4 illus, 13 ref

001330   CHAKRABORTY M, RAI V K, MITRA K (Physics Dep, St. Xavier’s Coll, Ranchi - 834 001, Email: mitesh.chakraborty@rediffmail.com) : Investigation on the electrical and optical properties of some zinc titanate ceramics. Pramana – J Phys 2019, 92(3), 46.

The ceramics of spinel zinc orthotitanate (SZT) and perovskite zinc metatitanate (PZT) sintered at 800^◦C have been prepared using the high-energy ball milling technique. The structural and optical characterisation of the prepared samples has been performed using X-ray diffraction and Fourier transformation of infrared (FT-IR) spectroscopy analysis. The measurements of frequency-dependent dielectric constant of the PZT and SZT ceramics sintered at 800^◦C have been performed in the (50−600)^◦C temperature range. Impedance spectroscopy studies have been reported for the prepared nanocrystalline ceramics. The empirical vibrational frequencies observed from the FT-IR spectra have been compared using the computational method of ORCA program package. Constraints for symmetry, bonds, angles or dihedral angles have not been applied in the geometry optimisation calculations. Hybrid three-parameter exchange-correlation functional of Becke, Lee, Yang, Parr with 20 % amount of exact exchange and Ahlrichs triple-zeta valence (def2-TZVP) basis set with polarisation function have been investigated for all atoms without considering the relativistic effects.

7 illus, 3 tables, 91 ref

001374   SURESH T P, UDAYANANDAN K M, BANNUR V M (Nehru Arts and Science Coll, Kanhangad - 671 314, Email: udayanandan@gmail.com) : Mayer’s convergence and thermodynamics of ideal Bose gas. Pramana – J Phys 2019, 92(3), 45.

The equation of state for a collection of ideal bosons in both the low-density and high-density regions is found using the method of cluster expansion with a new generating function. The importance of the radius of convergence in the cluster expansion and its connection to the Bose–Einstein condensation phenomenon are studied. The radius of convergence of the partition function is calculated and the values of critical density, fugacity and other thermodynamic properties at condensation are obtained using Mayer’s convergence method.

4 illus, 1 table, 17 ref

001340   ISLAM S, DATTA S, DAS T K (Physics Dep, Harish-Chandra Research Institute, Jhunsi, Allahabad - 211 019, Email: safiqulislam@hri.res.in) : A parametric model to study the mass–radius relationship of stars. Pramana – J Phys 2019, 92(3), 43.

In static space–time, we solve the Einstein–Maxwell equations. The effective gravitational potential and the electric field for charged anisotropic fluid are defined in terms of two free parameters. For such configurations, the mass of the star as a function of stellar radius is found in terms of two aforementioned parameters subjected to certain stability criteria. For various values of these two parameters, one finds that such a mass–radius relationship can model stellar objects located at various regions of the Hertzsprung–Russel diagram.

27 illus, 1 table, 62 ref

001371   SIVAGANESH G, ARULGNANAM A, SEETHALAKSHMI A N (Physics Dep, St. John’s Coll, Palayamkottai - 627 002, Email: gospelin@gmail.com) : A complete analytical study on the dynamics of simple chaotic systems. Pramana – J Phys 2019, 92(3), 42.

We report, in this paper, a complete analytical study on the bifurcations and chaotic phenomena observed in certain second-order, non-autonomous, dissipative chaotic systems. One-parameter bifurcation diagrams obtained from the analytical solutions revealing several chaotic phenomena such as antimonotonicity, period-doubling sequences and Feignbaum remerging have been presented. Further, the analytical solutions are used to obtain basins of attraction, phase portraits and Poincare maps for different chaotic systems. Experimentally observed chaotic attractors in some of the systems are presented to confirm the analytical results. The bifurcations and chaotic phenomena studied through explicit analytical solutions are reported in the literature for the first time.

14 illus, 20 ref

001375   TAKISA P M, MAHARAJ S D, MULANGU C (KwaZulu-Natal Univ, Durban 4000, South Africa, Email: maharaj@ukzn.ac.za) : Compact relativistic star with quadratic envelope. Pramana – J Phys 2019, 92(3), 40.

We consider an uncharged anisotropic stellar model with two distinct equations of state in general relativity. The core layer has a quark matter distribution with a linear equation of state. The envelope layer has a matter distribution which is quadratic. The interfaces between the core, envelope and the vacuum exterior regions are smoothly matched. We find radii, masses and compactifications for five different compact objects which are consistent with other investigations. In particular, the properties of the pulsar object PSR J1614-2230 are studied. The metric functions and the matter distribution are regular throughout the star. In particular, it is shown that the radii associated with the core and the envelope can change for different parameter values.

6 illus, 4 tables, 34 ref

001381   ZHAO C Y, ZHANG L, ZHANG C M (Hangzhou Dianzi Univ, Zhejiang- 310 018, China, Email: zchy49@hdu.edu.cn) : The FDTD simulation of microring feedback bend-based coupling resonator system for electromagnetically-induced transparency-like effect. Pramana – J Phys 2019, 92(3), 37.

A microring feedback bend-based coupling resonant system is proposed and is finite difference time domain (FDTD)-simulated to generate electromagnetically-induced transparency (EIT)-like transmission and mode distribution. The coupling between the cross-section of the waveguides gives rise to EIT-like spectrum. Most of the mode field energy is concentrated in the coupling region of the feedback bend. The full-width at half-maximum (FWHM) can be tuned by controlling the gap parameter between two feedback bends. The device enables integration with some photonic devices on a chip and shows great promise in applications such as fast–slow light and optical filters.

6 illus, 28 ref

001336   GARG S, JAIN A K (Physics Dep, Indian Institute of Technology Roorkee, Roorkee - 247 667, Email: swat90.garg@gmail.com) : Test of isospin conservation in thermal neutron-induced fission of ²⁴⁵Cm. Pramana – J Phys 2019, 92(3), 35.

We have recently shown that the general trends of partition-wise fission fragment mass distribution in heavy-ion-induced compound nuclear (CN) fission of heavy nuclei can be reproduced reasonably well by using the concept of isospin conservation, hence providing a direct evidence of isospin conservation in neutron-rich systems [Jain et al, Nucl Data Sheets 120, 123 (2014); Garg and Jain, Phys. Scr. 92, 094001 (2017); Jain and Garg, EPJ Web of Conference 178, 05007 (2018); Garg et al, Phys. Scr. 93, 124008 (2018)]. In this paper, we test the concept of isospin conservation to reproduce the fission fragment mass distribution emerging from thermal neutron-induced CN fission reaction, ²⁴⁵Cm(n_th,f). As earlier, we use Kelson’s conjectures [I Kelson, Proceedings of the Conference on Nuclear Isospin (Academic Press, New York, 1969)] to assign isospin to neutron-rich fragments emitted in fission, which suggest the formation of fission fragments in isobaric analogue states. We calculate the relative yields of neutron-rich fragments using the concept of isospin conservation and basic isospin algebra. The calculated results reproduce the experimentally known partition-wise mass distributions quite well. This highlights the usefulness of isospin as an approximately good quantum number in neutron-rich nuclei. This also allows us to predict the fragment distribution of the most symmetric Cd–Cd partition and the heavier mass fragment distributions, both not measured so far.

3 illus, 21 ref

001323   ALY A A (Physics Dep, Damanhour Univ, Damanhour, Egypt, Email: ayman.aly@cern.ch) : Thermodynamics analysis of Ricci dark energy models in bouncing Universe. Pramana – J Phys 2019, 92(3), 34.

Ricci dark energy (RDE) model in the framework of bouncing Universe is considered. Both the interacting and the non-interacting cases of the Ricci model of dark energy have been studied. Expressions for important cosmic parameters are reconstructed for the assumed model. It is noticed that the Universe undergoes a continuous expansion with a negative deceleration parameter for two scenarios. Also, Om diagnostic parameter has been established showing a type of quintessence-like behaviour over the given time range. The total entropy of the system is calculated and the validity of the generalised second law of thermodynamics is studied.

4 illus, 40 ref

001332   CHUNG W S, MAENG J (Physics Dep, Gyeongsang National Univ, Jinju 660-701, Korea, Email: mimip44@naver.com) : Truncated q-deformed fermion algebras and phase transition. Pramana – J Phys 2019, 92(3), 33.

In this paper, we apply the q-deformed fermion theory to the phase transition from the ordinary fermion into the truncated q-deformed fermion at the critical temperature T_c.

16 ref

001380   WANG X, LIU Y (Northeast Petroleum Univ, Daqing 163318, China, Email: lindaxinwang@126.com) : All single travelling wave patterns to fractional Jimbo–Miwa equation and Zakharov–Kuznetsov equation. Pramana – J Phys 2019, 92(3), 31.

By the complete discrimination system of polynomial method, we obtain the classification and representation of all single travelling wave solutions to (3 + 1)-dimensional conformal fractional Jimbo–Miwa equation and fractional Zakharov–Kuznetsov equation. These solutions show rich evolution patterns of models described by these two equations.

59 ref

001359   PENDAM N, VARDHANI C P (Physics Dep, Osmania Univ, Hyderabad - 500 007, Email: pnrphysics84@osmania.ac.in) : Design of optical Mach–Zehnder interferometer phase shifter in silicon-on-insulator. Pramana – J Phys 2019, 92(3), 30.

A passive TE mode phase shifter-based compact structure of optical Mach–Zehnder interferometer (MZI) using silicon-on-insulator (SOI) platform is demonstrated by using BPM simulations. Insertion loss was found, that is 9 dB for 3 μm width, 16 dB for 1.55 μm wavelength, 0.9 dB for 2000 μm path length (arms), and 15 dB for 0.0055 index differences between the core and the cladding of SOI of the designed device. The Mach–Zehnder interferometer attains good phase shifts by changing the path lengths (arm) with TE mode polarisation.

7 illus, 30 ref

000136   MANRO C, JAIN R (Physics Dep, IIS Univ (Deemed to be Univ), Mansarovar, Jaipur - 302 020, Email: manrochitra@gmail.com) : Investigation of temperature dependent dielectric relaxation studies of 4-bromoacetanilide in dilute solution of carbon tetrachloride. Asian J Chem 2019, 31(2), 463-8.

The changes in dielectric parameters of 4-bromoacetanilide in dilute solution of carbon tetrachloride with temperature variation are studied at a fixed frequency of 9.27 GHz. The investigation are being done for five different mole fractions of 4-bromoacetanilide in the microwave region. The values of dielectric constant (ε′) and dielectric loss (ε′′) are determined by using Heston et al. method. Permittivity at a static frequency (ε_o) and at an optical frequency (ε_∞) is calculated with the help of dipole meter and Abbe’s refractometer, respectively. Higasi’s method is used to calculate the values of relaxation times (τ₁, τ₂ and τ₀). From these values, it is found that the relaxation time decreases systematically with the increase in temperature. The fall of τ₂ with the increase in temperature has been observed to be more remarkable in comparison to the value of τ₁. It indicates that the rate of falls of the relaxation time related to intramolecular rotation with temperature is faster as compared to the internal group rotation.

4 illus, 3 tables, 36 ref

000134   MAHENDRAN N, JEYAKUMAR S J, JOTHIBAS M, MUTHUVEL A (PG & Research Physics Dep, T.B.M.L. Coll, Porayar - 609 307, Email: drsjohnson@rediffmail.com) : Structural, morphological, optical and photoluminescence properties of hafnium oxide nanoparticles synthesized by sol-gel method. Asian J Chem 2019, 31(2), 453-9.

The novel HfO₂ nanoparticles have been synthesized using sol-gel method. The samples were characterized by X-ray powder diffraction, scanning electron microscopy with elemental analysis, Fourier transform infrared spectrometer, UV-visible spectroscopy. The XRD patterns revealed the transition of cubic to monoclinic phase and calculated particle sizes are 34.92 and 35.66 nm in cubic phase and increase in molar concentration increased the size to 60.31 and 60.33 nm. The optical band gap energy decrease with increasing molar concentrations. We expect that this sol-gel method may be extended to the preparation of nanostructures of other kinds of metal oxides.

6 illus, 3 tables, 21 ref

000125   GATEA H A, NAJI I S (Physics Dep, Baghdad Univ, Baghdad, Iraq, Email: hamedalwan14@gmail.com) : Preparation and characterization of Ba_1-xSr_xTiO₃ by Sol-Gel method. Asian J Chem 2019, 31(1), 186-90.

Barium strontium titanate (BST) with formula (Ba_1-xSr_xTiO₃) has been synthesized by sol-gel method with different stoichiometric compositions (x = 0.3, 0.4, 0.5, 0.6). The raw materials which used to prepare compounds are (Ba,Sr) acetate as a source (Ba,Sr) and titanate isopropoxide source. The FE-SEM images showed that the particles size reduced from 464 to 13 nm when strontium concentration increased from 0.3 to 0.6. The X-ray diffraction studies have confirmed that Ba_0.7Sr_0.3TiO₃ sample have the tetragonal phase while remaining samples have a cubic phase. The intensity of the major peaks were decreased and shifted toward higher 2θ angles when Sr²⁺ ions increases.

4 illus, 2 tables, 26 ref

000131   KUMAR A, NADAF Y F, RENUKA C G (Physics Dep, Bangalore Univ, Bengaluru - 560 056, Email: renubub@gmail.com) : Solvatochromism of quinoline-390 and rhodamine-800: Multiple linear regression and computational approaches. Asian J Chem 2019, 31(1), 61-72.

The electronic absorption and emission spectra of laser dyes quinoline-390 and rhodamine-800 in distinct organic solvents have been analyzed to understand conventional interactions of solvents on the intensities, peak positions of both absorption and emission spectrum. The relationship between absorption spectrum (λ_max) and solvatochromic constants (ε, n, E) indicates that the peak positions are fundamentally influenced by non-specific and specific kind of interactions between the solute and solvent. Solvent effects on the electronic absorption band shift are characteristics of the degree of charge rearrangement of the solute molecules upon electronic excitation. These spectral shifts reflect the effect of the equilibrium solvents association across the energized solute particle, which adjusts inertially as a result of quick charge realignment upon radiative deactivation to the lowest electronic state. Spectral regression study techniques were carried out for the qualitative chemical analyses of these compounds, which provides an opportunity to assess electrical-optical molecular constants within the excited electronic conditions. Further TD-DFT computational techniques for optimized geometry, electronic structure and Mulliken charge distribution in vacuum and ethanol solvent were carried out to acquire additional knowledge of the molecular arrangement and electronic properties of these laser dyes.

10 illus, 9 tables, 60 ref

000114   BHATIA K G, BHATT N K, VYAS P R, GOHEL V B (Physics Dep, Gujarat Technological Univ, Ahmedabad - 382 424, Email: kamaldeep.bhatia1991@gmail.com) : Comparative study of transport properties using transition metal model potential (TMMP) for 16 liquid metals. Pramana – J Phys 2019, 92(2), 28.

We propose a pseudopotential of Kumar form with two parameters, the core radius (r_c) and the model radius (r_m), which in practice is reduced to a single-parameter potential taking r_m as the experimental atomic radius. The validity of the presently used pseudopotential is verified by carrying out a detailed study of transport properties of 16 liquid metals. The results of the liquid metal resistivities using the nearly free electron (NFE) Ziman’s approach and the single-site t-matrix approach are presented and compared with the experimental as well as other theoretical findings. Such comparative study confirms that the t-matrix approach is more appropriate and physically sound for a theoretical understanding of liquid metal resistivity, particularly in the case of transition metals. Furthermore, thermoelectric powers are also calculated using the present method and compared with the available experimental and theoretical results.

3 illus, 3 tables, 46 ref

000106   AL-BAHNAM N J (Physics Dep, Baghdad Univ, Baghdad, Iraq, Email: nabeil.physic@gmail.com) : The description of quantum dielectric function for insulators over Bethe surface. Pramana – J Phys 2019, 92(2), 27.

A new expression for the dielectric function is suggested here, which is the Mermin–Belkacem-Sigmund (MBS) model derived from the Belkacem–Sigmund (BS) model based on the conservation of a local particle number in the Mermin model. The energy loss function expressions are reviewed analytically for both models, and these dielectric functions were used to calculate the Bethe sum rule, the energy loss function (ELF), as well as the differential inelastic inverse mean free path (DIIMP) for H₂O. The indication from the results is that, compared to the BS dielectric function, the MBS dielectric function is more compatible in its consistency with the exact Bethe sum rule. The ELF for the MBS type is compatible relatively in high and low momentum transfers, while the ELF for the BS type is suitable for high-k. The two models of ELF were also applied to evaluate DIIMP for electron kinetic energy 1 keV, and these were compared with the results predicted in several ways via the SESINIPAC program, using the Mermin dielectric function and the extended Drude and Monte–Carlo method. These predicted results are in reasonable agreement with those estimated from other methods at the range of energy transfer (0–50) eV.

4 illus, 2 tables, 71 ref

000140   PAL S, MOITRA S, ANJUSHA V S, KUMAR A, MAHESH T S (Physics Dep, Indian Institute of Science Education and Research, Pashan 411 008, Email: soham.pal@students.iiserpune.ac.in) : Hybrid scheme for factorisation: Factoring 551 using a 3-qubit NMR quantum adiabatic processor. Pramana – J Phys 2019, 92(2), 26.

Quantum processors are potentially superior to their classical counterparts for many computational tasks including factorisation. Circuit methods as well as adiabatic methods have already been proposed and implemented for finding the factors of a given composite number. The main challenge in scaling it to larger numbers is the unavailability of large number of qubits. Here, we propose a hybrid scheme that involves both classical and quantum computation, based on the previous work of Peng et al, Phys. Rev. Lett. 101(22), 220405 (2008), which reduces the number of qubits required for factorisation. The classical part involves setting up and partially simplifying a set of bit-wise factoring equations and the quantum part involves solving these coupled equations using a quantum adiabatic process. We demonstrate the hybrid scheme by factoring 551 using a 3-qubit NMR quantum register.

4 illus, 2 tables, 25 ref

000127   GULATI K K, GULIA S, KUMAR N, KUMAR A, KUMARI S, GAMBHIR V, REDDY M N (Laser Science and Technology Centre (LASTEC), Delhi - 110 054, Email: kamalkumargulati@lastec.drdo.in) : Real-time stand-off detection of improvised explosive materials using time-gated UV–Raman spectroscopy. Pramana – J Phys 2019, 92(2), 20.

A transportable, trolley-mounted stand-off explosive material detection system based on the time-gated Raman spectroscopy was developed and tested in our laboratory. This system is capable of identifying the explosives and improvised explosive materials located up to a distance of 30 m. A frequency tripled Nd:YAG, nanosecond pulsed laser (355 nm, 6 ns) operated at 10 Hz was used as an excitation source to induce Raman spectra of explosive materials under investigation. A reflected type 200 mm aperture telescope designed using Zemax optical design software was used to collect the backscattered Raman signals. Raman signals were recorded using the gated intensified charge coupled device (ICCD) spectrograph. A LabVIEW-based data acquisition and analysis software for real-time identification of materials was developed and used. It gives audio as well as text alarm to the operator about threat identification.

4 illus, 19 ref

000121   DANANI C, AGGARWAL D, SWAMI H L, MENON V, SRIVATSAVA R, SHARMA A, SHARMA D, BINDU M H, AGRAWAL J, STEPHEN M M et al (Institute for Plasma Research, Bhat, Gandhinagar - 382 428, Email: chandan@ipr.res.in) : One-dimensional nuclear design analyses of the SST-2. Pramana – J Phys 2019, 92(2), 15.

Steady State Tokamak-2 (SST-2) will be an intermediate fusion machine before Indian DEMOnstration power reactor (DEMO) development to realise the reactor technologies. It is designed for fusion gain Q = 5 and fusion power in the range of 100–300 MW. Nuclear design analyses of SST-2 machine have been carried out to support the conceptual design work. Analyses have been carried out for two breeding blanket concepts: Indian lead–lithium ceramic breeder (LLCB) and helium-cooled ceramic breeder (HCCB). The analyses assess the tritium production and radiation shielding capability of the machine referring to the engineering design parameters. In this study, one-dimensional radiation transport calculations have been performed to assess the SST-2 nuclear responses for 1 full power year (FPY) operation. Nuclear responses such as tritium breeding ratio (TBR), various radiation loads to toroidal field (TF) coil have been calculated to obtain the radial build-up of SST-2 capable of breeding tritium and satisfying the shielding requirements. The assessment has been made using the ANISEN code and FENDL 2.1 cross-section library. It is observed that the TBRs with LLCB and HCCB blankets are 0.85 and 0.94, respectively. Shielding calculations confirm that the radial build is sufficient to protect the superconducting TF coils for 1 FPY.

4 illus, 5 tables, 22 ref

000157   ZHAO C Y, ZHANG C M (Hangzhou Dianzi Univ, Zhejiang 310018, China, Email: zchy49@hdu.edu.cn) : Electromagnetically-induced transparency-like transmission characteristics of a waveguide coupled to a microsphere resonator. Pramana – J Phys 2019, 92(1), 13.

The limitation of traditional microring mode resonance, the microsphere confocal cavity is the best candidate for a low loss and controllable linewidth. Based on the transform matrix method, we investigate the waveguide coupled to a microsphere whispering-gallery mode (WGM) system. We find that the confocal cavity mode is completely different from the traditional ring cavity mode. The confocal cavity mode is excited in asymmetrical dual microsphere systems, and the spectrum of asymmetrical dual microsphere systems appear as an electromagneticallyinduced transparency (EIT)-like profile, whereas the spectrum of symmetrical dual microsphere systems appears as Lorentz profile. The traditional ring cavity mode is excited in the symmetrical single microsphere system.

8 illus, 1 table, 16 ref

000155   YANG S-H, JIN M-H, WU J-W (Chongqing Normal Univ, Chongqing 401331, People’s Republic of China, Email: jwwu@cqnu.edu.cn) : Nonlinear process-induced spectral changes in hydrogenated amorphous silicon core optical fibre. Pramana – J Phys 2019, 92(1), 11.

In this paper, the spectral properties of temporal double pulses centred at the same central wavelength and two different central wavelengths are numerically presented based on hydrogenated amorphous silicon core optical fibre. In order to characterise the output spectra of double pulses, the group velocity dispersion and various nonlinear processes including self-phase modulation, cross-phase modulation, two-photon absorption, free carrier absorption and free carrier dispersion are considered in the theoretical model. Numerical results show that, under fixed fibre length condition, the widths of the outcome spectra are strongly dependent on the delay times, peak powers and initial chirps of input double pulses, i.e. widths of the output spectra are proportional to the launched peak powers, and the delay times control the separation between two pulses, resulting in the spectral change within a proper delay time, and the spectral widths are compressed or extended by judiciously adjusting the initial chirps imposed on the input pulses.

6 illus, 30 ref

000152   WANG H, WEN X-Y (Beijing Information Science and Technology Univ, Beijing 100192, China, Email: xiaoyongwen@163.com) : Dynamics of dark multisoliton and rational solutions for three nonlinear differential-difference equations. Pramana – J Phys 2019, 92(1), 10.

In this paper, three nonlinear differential-difference equations (NDDEs) from the same hierarchy are investigated using the generalised perturbation (n, N − n)-fold Darboux transformation (DT) technique. The dark multisoliton solutions in terms of determinants for three equations are obtained by means of the discrete N-fold DT. Propagation and elastic interaction structures of such soliton solutions are shown graphically. The details of their evolutions are studied through numerical simulations. Numerical results show the accuracy of our numerical scheme and the stable evolutions of such dark multisolitons without a noise. We find that the solutions of lower-order NDDEs in the same hierarchy are more robust against a small noise than their corresponding higher-order NDDEs. The discrete generalised perturbation (1, N − 1)-fold DT is used to derive some discrete rational and semirational solutions of the first equation, and a few mathematical features are also discussed. Results in this paper might be helpful for understanding some physical phenomena.

16 illus, 2 tables, 28 ref

000116   CHAI H-P, TIAN B, CHAI J, DU Z (Beijing Univ of Posts and Telecommunications, Beijing 100876, China, Email: tian_bupt@163.com) : Semirational rogue waves for the three coupled variable-coefficient nonlinear Schrödinger equations in an inhomogeneous multicomponent optical fibre. Pramana – J Phys 2019, 92(1), 9.

In this paper, we investigate the three coupled variable-coefficient nonlinear Schrödinger equations, which describe the amplification or attenuation of the picosecond pulse propagation in the inhomogeneous multicomponent optical fibre with different frequencies or polarisations. Based on the Darboux dressing transformation, semirational rogue wave solutions are derived. Semirational rogue waves, Peregrine combs and Peregrine walls are obtained and demonstrated. Splitting behaviour of the semirational Peregrine combs and attenuating phenomenon of the semirational Peregrine wall are exhibited. Effects of the group velocity dispersion, nonlinearity and fibre gain/loss are discussed according to the different fibres. We find that the maximum amplitude of the hump of the semirational rogue wave is less than nine times the background height due to the interaction between the soliton part and rogue wave part. Further, there is a bent in the soliton part of the semirational rogue.

11 illus, 47 ref

000135   MALIK A, KUMAR H, CHAHAL R P, CHAND F (Physics Dep, Pt. Neki Ram Sharma Government Coll, Rohtak - 124 001, Email: hkkhatri24@gmail.com) : A dynamical study of certain nonlinear diffusion–reaction equations with a nonlinear convective flux term. Pramana – J Phys 2019, 92(1), 8.

We explore the dynamics of quadratic and quartic nonlinear diffusion–reaction equations with nonlinear convective flux term, which arise in well-known physical and biological problems such as population dynamics of the species. Three integration techniques, namely the (G$\text{'}$/G)-expansion method, its generalised version and Kudryashov method, are adopted to solve these equations. We attain new travelling and solitary wave solutions in the form of Jacobi elliptic functions, hyperbolic functions, trigonometric functions and rational solutions with some constraint relations that naturally appear from the structure of these solutions. The travelling population fronts, which are the general solutions of nonlinear diffusion–reaction equations, describe the species invasion if higher population density corresponds to the species invasion. This effort highlights the significant features of the employed algebraic approaches and shows the diversity in the constructed solutions.

5 illus, 1 table, 61 ref

000145   SANTHOSH K P, SUKUMARAN I (Kannur Univ, Payyanur - 670 327, Email: drkpsanthosh@gmail.com) : Decay of Z = 82−102 heavy nuclei via emission of one-proton and two-proton halo nuclei. Pramana – J Phys 2019, 92(1), 6.

The halo structure of a nucleus is investigated on the basis of separation energy consideration and potential energy calculations. Most of the predictions on the existence of halo nuclei are found to agree with the available experimental studies. For the first time, the possibility of emitting proton halo (p-halo) nuclei from heavy nuclei within the range 82 ≤ Z ≤ 102 has been studied by evaluating decay half-lives for the emission of 1p-halo nuclei ⁸B, ¹²N, ¹³N, ¹⁷F and 2p-halo nuclei ⁹C, ¹⁷Ne, ¹⁸Ne, ²⁰Mg using Coulomb and proximity potential model (CPPM). Of these, the emissions of 1p-halo nuclei ⁸B, ¹²N, ¹³N and ¹⁷F are found to be probable from various heavy nuclei as the half-lives of the corresponding emissions are within the experimental upper limit (T_1/2 ≤ 10³⁰ s). When dealing with 2p-halo nuclei, its emission is observed to be less probable compared to 1p-halo nuclei, except ¹⁸Ne. Compared to the probability of emission of a normal cluster, the probability of emission of a p-halo nucleus from a radioactive nuclide is found to be less but still, there is a finite probability of p-halo emissions from heavy nuclei.

8 illus, 2 tables, 82 ref

000153   YADAV C P, PANDEY D K (Physics Dep, P.P.N. (P.G.) Coll, Kanpur - 208 001, Email: cpy99physics@gmail.com) : Pressure- and orientation-dependent elastic and ultrasonic characterisation of wurtzite boron nitride. Pramana – J Phys 2019, 92(1), 5.

The present study discloses the evaluation of second-order elastic constants of wurtzite boron nitride (w-BN) at room temperature and at different pressures using the many-body interaction potential model approach. Orientation- and pressure-dependent ultrasonic velocity, thermal relaxation time and other related thermophysical parameters (Debye temperature, Debye average velocity, specific heat and thermal energy density) are also calculated using the evaluated second-order elastic constants. The orientation-dependent thermal relaxation time of w-BN is predominantly affected by the Debye average velocity and is indirectly governed by second-order elastic constants. Thermal relaxation time of w-BN is found to decrease with pressure. Calculated elastic and ultrasonic properties of w-BN are compared with the properties of other wurtzite structured materials for a complete analysis and characterisation of the material.

6 illus, 1 table, 26 ref

000138   NAKHAEI O, SHAHTAHMASSEBI N, ROKNABADI M R, BEHDANI M (Physics Dep, Ferdowsi Univ of Mashhad, Mashhad 9177948974, Iran, Email: fajri.nakhaei@gmail.com) : Synthesis, UV-shielding and electromagnetic wave absorbing properties of polyvinylpyrrolidone-TiO₂/polyacrylonitrile-SiO₂ nanofibre nanocomposites. Bull Mater Sci 2019, 42(1), 42.

This paper reports electromagnetic interference (EMI) shielding effectiveness (SE) and UV-shielding performance of polyvinylpyrrolidone (PVP)–TiO₂/polyacrylonitrile (PAN)–SiO₂ nanofibre nanocomposites synthesized via the single nozzle co-electrospinning method. Herein, three samples with different average diameters were fabricated using 0.3, 0.4 and 0.5 ml h⁻¹ flow rates during the electrospinning process. Morphological characterization confirmed that a core–shell structure of nanofibre nanocomposites was formed successfully. The EMI SE of the as-prepared nanofibre nanocomposites was studied using a vector network analyser over the full X-band (8–12 GHz) frequency at room temperature. The experimental results demonstrate excellent microwave absorption properties for all samples. PVP–TiO₂/PAN–SiO₂ nanofibres with 596.67 nm average diameter show maximum total EMI (110 dB at about 9 GHz) and 98 % UV-shielding performance.

9 illus, 3 tables, 33 ref

000108   ALI M A, KHAN N, AHMAD F, ALI A, AYAZ M (Physics Dep, Government Post Graduate Jahanzeb Coll Saidu Sharif Swat, KPK 19130, Pakistan, Email: azmatupesh@gmail.com) : First-principles calculations of opto-electronic properties of IIIAs (III = Al, Ga, In) under influence of spin–orbit interaction effects. Bull Mater Sci 2019, 42(1), 36.

In this article, we present first-principles calculations for structural and opto-electric properties of IIIAs (III = Al, Ga, In) in the zinc-blende phase. Our calculations are based on the full potential-linearized augmented plane wave method implemented in the WIEN2k code. We employed Perdew–Burke–Ernzerhof generalized gradient and modified Becke–Johnson approximations as exchange–correlation potentials. Our calculated structure parameters are found to be in reasonable agreement with the available literature. It was found that the inclusion of spin–orbit interaction effect shifts the conduction band minima towards the Fermi level and provides band gaps very close to their experimental values. The optical properties such as complex dielectric functions, complex refractive indices, reflectivities, energy loss functions, optical conductivities and absorption coefficients at varied frequencies were investigated in detail. We found that static real part of dielectric functions and refractive index decreases with increase in band gap. Our calculated critical point energies (eV) are consistent with the experimental results.

10 illus, 3 tables, 54 ref

000112   BASU P K, KUMBHAR S, SREEJITH K P, YADAV T S, KOTTANTHARAYIL A, ARORA B M, NARASIMHAN K L, SHARMA A K (National Centre for Photovoltaic Research and Education (NCPRE), Mumbai - 400 076, Email: prabir.basu@nus.edu.sg) : Active area cell efficiency (19%) monocrystalline silicon solar cell fabrication using low-cost processing with small footprint laboratory tools. Bull Mater Sci 2019, 42(1), 33.

A high efficiency (>18 %) industrial large area crystalline silicon wafer solar cell fabrication process generally requires industrial equipment with large footprint, high capital and running costs. Stricter processing window, continuous monitoring and automated functioning are the reasons for it. However, for any conventional laboratory (lab) it is always difficult to manage these requirements with limited available lab space or insufficient fund and other related resources. In this work, we report a novel way to fabricate high efficiency full area aluminium back surface field monocrystalline silicon wafer solar cells in our lab using low-cost processing with small-footprint fabrication tools for 6 inch pseudo-square industrial wafers. The novelty of our work includes optimization of every fabrication process step, e.g., texturization, emitter diffusion, emitter passivation and anti-reflection coating deposition, edge-isolation, screen printing and co-firing individually. These modifications include tuning of processing tools and processes, utility changes and inclusion of additional process steps. Beaker-based chemical processes, manual diffusion furnace, introduction of low temperature oxidation, low temperature silicon nitride deposition processes, plasma-edge isolation tool, single manual screen printer, single oven drying of metal pastes and co-firing using rapid thermal processing tools were used at our lab. For our cells, actual and active area efficiencies of 18.5 and 19 % (measured under AM1.5G 1 Sun condition), respectively, were achieved.

15 illus, 2 tables, 10 ref

000124   ER I K, GIRTEKIN A O C, CORLU T, YILDIRIM M A, ATES A, ACAR S (Physics Dep, Gazi Univ, Ankara 06500, Turkey, Email: karaduman.irmak@gmail.com) : Low-level NO gas sensing properties of Zn_1−xSn_xO nanostructure sensors under UV light irradiation at room temperature. Bull Mater Sci 2019, 42(1), 32.

Zn_1−xSn_xO (x = 0, 0.05, 0.10, 0.15, 0.20) nanostructures have been grown through the successive ionic layer adsorption and reaction method. The structural, morphological and compositional properties of the nanostructures have been characterized through X-ray diffraction, scanning electron microscope and energy dispersive X-ray analysis, respectively. The NO gas sensing properties of sensors to 20 ppb have been systematically investigated in the dark and under UV light irradiation. A Zn_0.90Sn_0.10O sensor has exhibited the highest response for 20 ppb NO gas compared with other sensors. The sensor response has increased from 1.9 to 43 % depending on the UV light irradiation for the Zn_0.90Sn_0.10O sensor. Zn_0.90Sn_0.10O nanostructure can be used as a suitable gas sensor material for detection of low concentration levels of NO gas.

6 illus, 1 table, 20 ref

000104   ABOU-MESALAM M M, ABASS M R, IBRAHIM A B, ELSEMAN A M, HASSAN A M (Electronic and Magnetic Materials Dep, Central Metallurgical Research and Development Institute (CMRDI), Helwan, Cairo 11421, Egypt, Email: AhmedMourtada5555@yahoo.com) : Tunable optical and dielectric properties of polymeric composite materials based on magneso-silicate. Bull Mater Sci 2019, 42(1), 31.

Magneso-silicate (MgSi) as an inorganic ion exchange material was synthesized by a precipitation technique. Then, the MgSi was impregnated into polyacrylamide acrylic acid and its composites (Poly) by condensation polymerization. To study the effect of γ-radiation, the polyacrylamide acrylic acid and its MgSi samples were synthesized using γ-irradiating systems at 25, 65 and 90 kGy. The variations in the radiation dose and amorphous structure were altered and confirmed by X-ray diffraction (XRD). Moreover, the absorbance and band-gap energy were enhanced by inserting MgSi into the polymeric composites (Poly). Furthermore, variations in temperature with dielectric constant, dielectric loss and conductivity of the samples at various frequencies from 100, 500, 1000, 2000 to 4000 Hz have been explained.

8 illus, 3 tables, 59 ref

000133   MAHBOOB S, RIZWANA, PRASAD G, KUMAR G S (Physics Dep, Osmania Univ, Hyderabad - 500 007, Email: mahboob1978@yahoo.com) : Enhanced dielectric and piezoelectric properties in microwave sintered (Ba_0.997Nd_0.003)TiO₃ ceramic when compared to conventional sintered ceramics. Bull Mater Sci 2019, 42(1), 30.

Dielectric, conductivity and piezoelectric properties have been studied on (Ba_0.997Nd_0.003)TiO₃ ceramic samples prepared through microwave sintered (MWS) and conventional sintered (CS) routes and the results are presented in this paper. The room temperature dielectric constant at 10 kHz for CS and MWS samples are 1245 and 5250 respectively. Room temperature dielectric constant in MWS sample was almost four times higher than that of the CS sample. The value of K_t is found to be 0.998 and 0.997; whereas the value of d₃₃ is 7.72 nm V⁻¹ (573 K) and 444.66 nm V⁻¹ (573 K) for CS and MWS samples, respectively. In the present study almost 57 times enhancement in piezoelectric charge constant (d₃₃) is observed for the MWS Ba_0.997Nd_0.003TiO₃ ceramic when compared to the CS ceramic.

8 illus, 2 tables, 16 ref

000150   TRIPATHI M, BOBADE S M, KUMAR A (Physics Dep, C.C.S. Univ, Uttar Pradesh - 200 004, Email: anujkumar.jiet@gmail.com) : Preparation of polyvinylidene fluoride-co-hexafluoropropylene-based polymer gel electrolyte and its performance evaluation for application in EDLCs. Bull Mater Sci 2019, 42(1), 27.

Polymer gel electrolyte (PGE) film is prepared by incorporating polyvinylidene fluoride-co-hexafluoropropylene (PVDF-HFP) as polymer, ethylene carbonate (EC)-propylene carbonate (PC) as plasticizers and tetraethylammonium tetrafluoroborate (TEABF₄) as salt using solution cast technique. By varying weight percentages of EC-PC-TEABF₄ into a host polymer, different samples of PGE were prepared, and the concentration of EC-PC-TEABF₄ was optimized for maximum conductivity, and stability of the prepared film. The maximum ionic conductivity of the order of 4.9 × 10⁻³ S cm⁻¹ was determined for 80 wt % of [EC-PC (1:1 v/v)-TEABF₄ (1.0 M)]. From the conductivity as a function of temperature, activation energy E_a was calculated and it is about 0.06 eV. Overall, the amorphous structure was confirmed by X-ray diffraction analysis. Dielectric and impedance spectroscopic analysis was also carried out to understand the electrical behaviour of electrolyte using modified Debye’s function. An ionic character of prepared electrolyte was confirmed from DC polarization method. The ionic transference number of 0.91 was calculated from the data while the electrical potential stability window was found to be 3.8 V. The electrical performance of prepared PGE was examined by fabricating electrical double-layer capacitor (EDLC). In a supercapacitor, commercially procured activated carbon electrodes were employed. The specific capacitance of EDLC cell is found to be $~$60 mF cm⁻², and equivalent single-electrode capacitance is about 39 F g⁻¹.

11 illus, 5 tables, 34 ref

000105   AFSHARIMANI N, NYSTEN B (Catholique de Louvain Univ, 1348 Louvain-la-Neuve, Belgium, Email: nasima.afsharimani@tnuni.sk) : Hybrid gate dielectrics: A comparative study between polyvinyl alcohol/SiO₂ nanocomposite and pure polyvinyl alcohol thin-film transistors. Bull Mater Sci 2019, 42(1), 26.

Polyvinyl alcohol (PVA) thin films as polymer gate dielectrics, with and without SiO₂ nanoparticles were fabricated using spin-coating. Surface roughness and hydrophilicity of PVA and PVA/SiO₂ thin films were studied by contact-angle measurements and atomic force microscopy. The dielectric properties were characterized via capacitance and leakage-current measurements on metal–insulator–metal structures. In order to further investigate the application potential of such materials as a replacement for conventional inorganic dielectrics such as SiO₂ in organic thin-film transistors, devices were fabricated based on these polymers using α, ω-dihexylquaterthiophene as an active layer. Performance of the devices was realized by electrical measurements and Kelvin probe force microscopy. All transistors showed hole and electron mobilities in the low-voltage range. PVA/SiO₂ films showed larger capacitance, less hydrophilicity, rougher surfaces and considerable leakage currents compared with those with neat PVA. Although integrating nanoparticles modified surface electronic properties and showed a shift in surface potential as observed in Kelvin probe force measurements, it appears that non-polymeric and neat polymeric dielectric materials could still be a privilege to nanocomposite polymeric dielectrics for optoelectronic applications.

5 illus, 1 table, 41 ref

000126   GUINTER E, FONTANA L C, BECKER D (Estado de Santa Catarina Univ - UDESC, Joinville, SC, Brazil, Email: daniela.becker@udesc.br) : Maleic anhydride film deposition through an active screen plasma system. Bull Mater Sci 2019, 42(1), 23.

The active screen plasma system has been extensively studied over the past few years, mainly for plasma nitriding purposes. This technique also provides possibilities of treating non-electrical conducting materials, such as polymeric ones, which is unattainable with a conventional DC plasma system. In this work, an active screen plasma setup for maleic anhydride (MA) film deposition on a glass substrate was used. The plasma working gas was a mixture of argon and MA vapour. Films obtained through conventional plasma discharge were compared with the active screen deposition process, in both DC and pulsed-mode plasma. The samples were characterized through Fourier-transform infrared spectroscopy and static contact angle between the film’s surface and droplets of distilled water. Film thickness measurements were performed through profilometry. Results showed that MA films obtained through the active screen system are thicker and more efficiently preserve the anhydride groups than those obtained from conventional plasma discharge.

3 illus, 3 tables, 22 ref

000111   BARAKER B M, LOBO B (Physics Dep, Karnatak Science Coll, Dharwad 580 001, Karnataka, Email: blaise.lobo@gmail.com) : Dielectric relaxation in a cadmium chloride-doped polymeric blend. Bull Mater Sci 2019, 42(1), 18.

The temperature- and frequency-dependent relaxation processes in films of a polymeric blend comprising a polyvinyl alcohol (PVA)/polyvinyl acetate (PVAc) co-polymer blended with polyvinyl pyrrolidone (PVP) in equal proportion by weight, and doped with an inorganic metallic salt, cadmium chloride (CdCl₂), at 0.0 wt % and 10.2 wt % doping levels (DLs), have been studied using dielectric relaxation spectroscopy (DRS). The frequency response of dielectric parameters for these samples has been studied with variation in temperature, from 303 up to 373 K, at different fixed frequencies (from 12 Hz up to 200 kHz). Study of Cole–Cole plots reveals a decrease in bulk resistivity of the samples with increase in temperature, which is attributed to thermally induced increase in the mobility of polymer chains. A 10-fold increase in bulk conductivity is observed for doped films with a DL of 10.2 wt %, when compared with the bulk conductivity of the un-doped (0.0 wt % DL) sample. The temperature dependence of dielectric parameters at different frequencies has been studied and the activation energy has been calculated. The relaxation time is found to be of the order of a few milliseconds, which implies that electrical conduction in CdCl₂-doped PVA/PVAc–PVP blend films is predominantly due to the migration of ions. The variation of AC conductivity with frequency is in agreement with Jonscher’s universal power law. AC conductivity of the sample is found to increase significantly with an increase in temperature of the sample. Frequency-dependent dielectric properties of CdCl₂-doped PVA/PVAc–PVP blend films, for various DLs, are also studied at room temperature.

12 illus, 4 tables, 60 ref

000148   SINGH R (Physics Dep, Sri Guru Gobind Singh Coll, Chandigarh - 160 019, Email: ranber14@gmail.com) : Liquid hydrogen at the thermodynamic conditions of room temperature and a pressure of 490 GPa. Bull Mater Sci 2019, 42(1), 9.

We investigate the effect of nuclear quantum effects in liquid hydrogen at the thermodynamic conditions of room temperature and a pressure of 490 GPa. The calculated pair-correlation function shows that the nuclear quantum effects are quite significant for the correct description of liquid atomic hydrogen at high pressures.

4 illus, 20 ref

000143   RAVIKUMAR M, CHANDRAMOHAN R, KUMAR K D A, VALANARASU S, GANESH V, SHKIR M, ALFAIFY S, KATHALINGAM A (Physics Dep, Arul Anandar Coll, Karumathur - 625 514, Email: valanroyal@gmail.com) : Effect of Nd doping on structural and opto-electronic properties of CdO thin films fabricated by a perfume atomizer spray method. Bull Mater Sci 2019, 42(1), 8.

A perfume atomizer-assisted spray pyrolysis method was employed to fabricate undoped and neodymium (Nd)-doped cadmium oxide (CdO) thin films. X-ray diffraction results reveal that all the films are polycrystalline with a cubic structure with a preferential orientation along the (200) direction. Scherrer’s formula was used to calculate the crystallite size of Nd-doped CdO films. Energy dispersive spectroscopy results show that Cd, Nd and O elements are present in Nd-doped CdO thin films. The optical absorption of the doped films is increased along with increasing Nd-doping level. The prepared CdO thin films have a high absorption coefficient in the visible region and the optical band gap is decreased on increasing Nd doping content. The electrical carrier concentration (n) of the deposited films is increased with increasing Nd doping concentration. Photoconductivity studies of a nanostructured Al/Nd–n-CdO/p-Si/Al device showed a non-linear electric characteristics indicating diode-like behaviour. Prepared Nd:CdO films could increase the photo-sensing effect of this n-CdO/p-Si heterostructure. These Nd-doped CdO thin films may open a new avenue for photodiode application in near future.

9 illus, 3 tables, 51 ref

000113   BENRAMACHE S, AOUN Y, LAKEL S, BENHAOUA B, TORCHI C (Biskra Univ, Biskra-07000, Algeria, Email: benramache.said@gmail.com) : The calculate of optical gap energy and urbach energy of Ni_1-xCo_xO thin films. Sadhana 2019, 44(1), 26.

The effect of Co doping on optical, structural and electrical properties of Ni_1-xCo_xO thin films has been successfully deposited on glass substrate by Sol–Gel Sping coating technique. The main objective of this research is to study the Ni_1-xCo_xO thin films to determine the optical gap energy by various methods and compare of calculated values. The transmission spectra show that the Ni_1-xCo_xO thin films have a good optical transparency in the visible region. The optical gap energy was varied between 3.8 and 4.05 eV, which was determined by various methods and equations. These are found in the drawn of A, A² , $\mathrm{\alpha }$, $\mathrm{\alpha }$² (Ahν)² and ($\mathrm{\alpha }$hν)² as a function of the photon energy hv, the suitable method to calculate the optical energy was observed for (Ahν)² versus hv, but this method can not be related to the film thickness. The urbach energy of the Ni_1-xCo_xO thin films also was determined by the curves of LnA and Ln$\mathrm{\alpha }$ as a function of photon energy hv. The deduce by LnA versus hv is also suitable to estimate the urbach energy. However, the Ni_0.96Co_0.04O thin films have a few defects with minimum value of urbach energy. XRD patterns of the Ni_1-xCo_xO thin films indicate that some films are polycrystalline with cubic structure. The electrical conductivity of our films is in the order of 8.2*10^-3 ($\mathrm{\Omega }$.cm)¹ .

7 illus, 1 table, 25 ref

000158   ZHENG X, CHI H-C, LIN S-T, JIANG G, QIAO C, HUANG K-N (Sichuan Univ, Chengdu 610064, Sichuan, China, Email: knhuang1206@gmail.com) : Relativistic photoionization of H-isoelectronic series including plasma shielding effects. Indian J Phys 2019, 93(2), 267–77.

With plasma shielding effects of the Debye–Hu¨ckel model, we investigate the relativistic photoionization processes of H, Nb⁴⁰⁺ and Pb⁸¹⁺ plasmas in the H-isoelectronic series. The shielded nuclear potential of Yukawa type experienced by the electron is parameterized by Debye length D. To account for relativistic effects non-perturbatively, we solve the Dirac equation for the bound as well as continuum wavefunctions. Contributions from multipole fields are calculated for high incident photon energies, while the angular distribution and spin polarization parameters of photoelectrons are provided in the electric dipole approximation. Our results of photoionization cross sections for the H plasma agree with other available theoretical calculations. The interplay between the relativistic and plasma shielding effects on the photoionization parameters is also studied.

11 illus, 4 tables, 30 ref

000123   DUTTA D, GOSWAMI K S (Physics Dep, Gauhati Univ, Assam - 781 014, Email: dutta_dharitree@yahoo.com) : Dust ion acoustic double layer in the presence of superthermal electrons. Indian J Phys 2019, 93(2), 257–65.

The existence of a dust ion acoustic double layer in a collisionless, un-magnetized, multi-component plasma is reported here. The plasma model consists of ions, negatively charged dust particles and two components of superthermal electrons. By following Sagdeev potential and reductive perturbation method, the electrostatic double layer of negative polarity is shown to exist in small-amplitude regime. From the analytical study, it is observed that the amplitude of the double layer depends upon various parameters of the superthermal electrons as well as on the dust concentration. The model considered here has a good match with the data obtained from Cassini spacecraft for outer magnetosphere of Saturn ($~$ 14 R_s, R_s being the radius of Saturn). So, the results obtained from this study are useful for understanding the nature of the plasma waves in Saturn magnetosphere.

8 illus, 29 ref

000156   YU B, ZHANG Q, JIAN Z (Physics Dep, Xinzhou Teachers Univ, Xinzhou 034000, Shanxi, China, Email: yubo6688@126.com) : Real-time compensation of single photons polarization state drift based on genetic algorithm. Indian J Phys 2019, 93(2), 251–5.

We present an automatic single photons polarization state control system. The single photons polarization state optimizing results are theoretically simulated based on genetic algorithm. With the optimized integration time, single photons polarization state drift is experimentally compensated using the four-channel polarization controller manipulated by genetic algorithm. The intensity fluctuation is less than 3 % for an arbitrary input polarization state transformed into the stable output polarization state.

7 illus, 18 ref

000151   WANG D-H (Ludong Univ, Yantai 264025, China, Email: lduwdh@163.com) : Photodetachment dynamics in the time-dependent oscillating electric and magnetic fields. Indian J Phys 2019, 93(2), 243–50.

We study the photodetachment dynamics of H^- ion in the time-dependent oscillating electric and magnetic fields for the first time. The wave function of the detached electron at a given point on the detector plane is constructed using the semiclassical method, which is related to the electron trajectories in the oscillating electric and magnetic fields. It is found due to the interplay of the time-dependent oscillating electric and magnetic fields, multiple electron trajectories emitted from the negative ion source can arrive at a given detector point. The interference between these electron trajectories causes the oscillatory structures in the electron probability density. Modifications of electron probability density caused by different oscillating electric and magnetic fields and the position of the detector plane are also studied and explained. It is shown that even at a macroscopic distance from the negative ion source, the interference patterns in the electron probability density can be seen clearly, which can be realized in an actual photodetachment experiment. Therefore, our work can serve as a guide for the future experimental studies of the photodetachment of negative ions in the oscillating electric and magnetic fields.

8 illus, 27 ref

000147   SINGH M K, SINGH V, SUBRAHMANYAM V S, WONG H T (Physics Dep, Banaras Hindu Univ, Varanasi - 221005, Email: singhmanoj59@gmail.com) : Characterization of the hybrid neutron detector. Indian J Phys 2019, 93(2), 235–42.

We report the performance and characterization of a custom-built hybrid neutron detector (HND). The HND consists of BC501A liquid and BC702 phosphor powder scintillation neutron detectors, which is sensitive for the fast and thermal neutrons, respectively. Software analysis packages are developed to derive the energy spectra and compare with measured ones. Position variation of the Compton edge, the maximum probability and the location of the half-maximum intensity for the different $\mathrm{\gamma }$-peaks of various sources (i.e., ²²Na, ⁶⁰Co, ¹³⁷Cs) used in this study is presented.

9 illus, 7 ref

000141   PU J-C, HU H-C (Shanghai for Science and Technology Univ, Shanghai- 200 093, China, Email: PJuncai@163.com) : Exact solitary wave solutions for two nonlinear systems. Indian J Phys 2019, 93(2), 229–34.

In this paper, we employ the powerful sine-Gordon expansion method in investigating the solitary wave solutions of the fifth-order nonlinear equation and the Date–Jimbo–Kashiwara–Miwa equation with symbolic computation. We obtain the hyperbolic, trigonometric and complex solutions and the corresponding plots of the solitary wave solutions are given out analytically and graphically.

4 illus, 33 ref

000149   STAHLBERG R, YOO H, POLLACK G H (Bioengineering Dep, Washington Univ, WA 98195, USA, Email: raista@u.washington.edu) : Origin of the infra-red emission peak in freezing water. Indian J Phys 2019, 93(2), 221–7.

When droplets of purified water (1–5 $\mathrm{\mu }$l) were cooled from the bottom, they slowly and continuously supercooled before releasing latent heat as a transient burst of infra-red (IR) radiation. In order to determine the role of this IR emission, a thin rectangular water layer was cooled unilaterally while imaged from above by an infrared (FLIR) camera. The first noticeable event was an IR burst that rapidly (< 0.1 s) moved through a 5-mm-long path of water. Final solidification of the water layer was recognized by an increase in volume, as the meniscus at the air interface changed from concave to convex. The propagation of the IR burst through the water layer preceded the first visible onset of volume increase and solidification by more than one second. The transient and early appearance of the IR burst belongs to what is called the first stage of freezing. This stage has been linked to the formation of so-called spongy ice. Both IR burst and pinnately shaped spongy ice appear at the same time and share a short transient existence. It is only this early type of ice that is associated with the IR burst. By contrast, the later-occurring solid ice formation parallels a diminishing IR emission.

7 illus, 23 ref

000120   CUI K, ZHAO Z, CHEN S, GAO J, WEI L, GUO J (Northwestern Polytechnical Univ, P.O. Box 412, Xi’an 710072, China, Email: zhaolong@nwpu.edu.cn) : Capillary flows along microchannels in the presence of magnetic field. Indian J Phys 2019, 93(2), 213–9.

To analytically determine liquid depth and velocity, we formulated a theoretical a capillary flow. The coupling effects of viscous force (F_v), capillary force (F_s), and electromagnetic force (F_m) were considered during the modeling process. Periodical electromagnetic force facilitates capillary flow in hydrophilic conditions, and velocity vibration synchronizes with electromagnetic force. A sufficiently high electromagnetic force was required for ensuring the upward movement of liquid front in hydrophobic conditions. Liquid depth was increased with the increase in magnetic field, damping factor, and angular frequency. The velocity peak was positively related to $\left| \cos \mathrm{\theta } \right|$ and magnified with the increase in damping factor and angular frequency in hydrophilic conditions. However, variations in velocity in hydrophobic conditions experienced an initial forward instantaneous peak and became consistent with that of hydrophilic conditions because of electromagnetic force.

6 illus, 22 ref