Published by De Gruyter

Volume 75 Issue 3

Issue of Zeitschrift für Naturforschung A

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Contents
Journal Overview

Publicly Available March 2, 2020

Frontmatter

Page range: i-iii

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Dynamical Systems & Nonlinear Phenomena

December 10, 2019

Bifurcation Analysis for Small-Amplitude Nonlinear and Supernonlinear Ion-Acoustic Waves in a Superthermal Plasma

Durga Prasad Chapagai, Jharna Tamang, Asit Saha

Page range: 183-191

Abstract

Bifurcation analysis of small-amplitude nonlinear and supernonlinear periodic ion-acoustic waves (SNPIAWs) is reported in a three-constituent superthermal plasma composing of cold fluid ions and kappa-distributed electrons of two temperatures (cold and hot). Using the reductive perturbation technique, the plasma system is studied under the Korteweg-de Vries (KdV) and the modified KdV (mKdV) equations. Furthermore, the KdV and mKdV equations are transformed into planar dynamical systems applying travelling wave transfiguration. Possible qualitative phase profiles for the corresponding dynamical systems controlled by system parameters (κ,αc,αh$\kappa,{\alpha_{c}},{\alpha_{h}}$ and f ) are shown. Small-amplitude SNPIAW solution for the mKdV equation is presented for the first time. Small-amplitude nonlinear periodic ion-acoustic wave (NPIAW) and ion-acoustic solitary wave solutions (IASWS) for both the KdV and mKdV equations are obtained. Effects of parameters κ and α h on IASW, NPIAW and SNPIAW solutions are investigated.

February 7, 2020

Propagation of Waves in a Nonideal Magnetogasdynamics with Dust Particles

Kajal Sharma, Rajan Arora, Astha Chauhan, Ashish Tiwari

Page range: 193-200

Abstract

In this article, we use the surface theory and compatibility conditions to describe the behaviour of wave propagation and their culmination into a shock wave in nonideal reacting gas with dust particles. The one-dimensional steepening of waves has been considered. A Bernoulli-type transport equation for the velocity gradient has been obtained. A numerical approach is used to explain the effects of van der Waals excluded volume of the medium, the ratio of specific heats, and the mass concentration of the solid particles on the shock wave.

January 15, 2020

Delta-Shock Solution to the Eulerian Droplet Model by Variable Substitution Method

Yanyan Zhang, Yu Zhang

Page range: 201-210

Abstract

By introducing a special kind of variable substitution, we skillfully solve the delta-shock and vacuum solutions to the one-dimensional Eulerian droplet model. The position, propagation speed, and strength of the delta shock wave are derived under the generalised Rankine–Hugoniot relation and entropy condition. Moreover, we show that the Riemann solution of the Eulerian droplet model converges to the corresponding the pressureless Euler system solution as the drag coefficient goes to zero.

March 2, 2020

Solitary Wave with Quantisation of Electron’s Orbit in a Magnetised Plasma in the Presence of Heavy Negative Ions

Manoj Kr. Deka, Apul N. Dev

Page range: 211-223

Abstract

The propagation characteristics of solitary wave in a degenerate plasma in the presence of Landau-quantised magnetic field and heavy negative ion are studied. The nature of solitary wave in such plasma under the influence of magnetic quantisation and the concentration of both electrons and negative ions, as well as in the presence of degenerate temperature, are studied with the help of a time-independent analytical scheme of the solution of Zakharov–Kuznetsov equation. The electron density, as well as the magnetic quantisation parameter, has an outstanding effect on the features of solitary wave proliferation in such plasma. Interestingly, for any fixed electron density, the magnetic quantisation parameter has an equal control on the maximum height and dispersive properties of the solitary wave. Toward higher temperatures and higher magnetic fields, the width of the solitary wave decreases. For a lower magnetic field, the maximum amplitude of the solitary wave decreases rapidly at higher values of degenerate temperature and negative ion concentration; however, at a lower value of degenerate temperature, the maximum amplitude increases with increasing negative ion concentration.

February 7, 2020

Heat and Mass Transfer of Temperature-Dependent Viscosity Models in a Pipe: Effects of Thermal Radiation and Heat Generation

Fayyaz Ahmad, Mubbashar Nazeer, Mubashara Saeed, Adila Saleem, Waqas Ali

Page range: 225-239

Abstract

In this paper, a study of the flow of Eyring-Powell (EP) fluid in an infinite circular long pipe under the consideration of heat generation and thermal radiation is considered. It is assumed that the viscosity of the fluid is an exponential function of the temperature of the fluid. The flow of fluid depends on many variables, such as the physical property of each phase and shape of solid particles. To convert the given governing equations into dimensionless form, the dimensionless quantities have been used and the resultant boundary value problem is solved for the calculation of velocity and temperature fields. The analytical solutions of velocity and temperature are calculated with the help of the perturbation method. The effects of the fluidic parameters on velocity and temperature are discussed in detail. Finite difference method is employed to find the numerical solutions and compared with the analytical solution. The magnitude error in velocity and temperature is obtained in each case of the viscosity model and plotted against the radius of the pipe. Graphs are plotted to describe the influence of various parameter EP parameters, heat generation parameter and thermal radiation parameters against velocity and temperature profiles. The fluid temperature has decreasing and increasing trends with respect to radiation and heat generations parameters, respectively.

Solid State Physics & Materials Science

January 15, 2020

Michelson Interferometric Hydrogen Sulfide Gas Sensor Based on NH₂-rGO Sensitive Film

Shaodian Liu, Xiaozhan Yang, Wenlin Feng, Hongliang Chen, Yu Tao, Yi Jiang

Page range: 241-248

Abstract

A highly sensitive hydrogen sulfide gas sensor based on NH 2 -rGO-coated thin-core-fibre (TCF) Michelson interferometer (MI) is proposed and evaluated. Two sections of TCFs are alternately sandwiched between three single-mode-fibres (SMFs). A Faraday rotator mirror (FRM) is fixed to the end of the last SMF to reflect the light signal and enhance the interference. Then the structure SMF-TCF-SMF-TCF-SMF-FRM (STSTS-F) is successfully constructed. NH 2 -rGO, as sensing film, is coated on two TCFs and is used to detect traces of hydrogen sulfide gas. Raman spectra and XPS analysis show that NH 2 -rGO has been successfully synthesised. The thickness of the NH 2 -rGO film coated on the TCF surface is about 500 nm. By introducing 0–60 ppm hydrogen sulfide gas into the chamber, with the increase in concentration of the gas, the monitoring trough exhibits a blue shift. Our experimental results show that the sensor has good linearity ( R 2 = 0.98096) and selectivity for hydrogen sulfide gas. The sensitivity is 21.3 pm/ppm, and the response and recovery times are about 72 and 90 s, respectively. The sensor has the advantages of high sensitivity, high selectivity, and small size, enabling the detection of trace hydrogen sulfide in toxic gas environments.

February 7, 2020

Insight into the Structural, Electrical, and Magnetic Properties of Al-Substituted BiFeO₃ Synthesised by the Sol–Gel Method

Mukhtar Ahmad, Rizwan Ali, Atiq ur Rehman, Akbar Ali, Ishrat Sultana, Ihsan Ali, Muhammad Asif

Page range: 249-256

Abstract

Multiferroics with chemical formula BiAl x Fe 1− x O 3 ( x = 0, 0.1, 0.2, and 0.3) and substituted by Al are synthesised using sol–gel auto-combustion. The materials are sintered at 500 °C for 5 h. In the ongoing study, the crystal structure of BiAl x Fe 1− x O 3 was investigated by X-ray diffraction. After confirming the rhombohedral single-phase crystal structure, various characterisation techniques, such as scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, elemental mapping images, electrical properties, Fourier transform infrared spectroscopy, and vibrating sample magnetometry (VSM), were used to investigate the synthesised samples. The grain size estimated from SEM images decreased as Al contents increased. Elemental composition was confirmed by EDX spectra. Direct current electrical resistivity increased whereas drift mobility decreased with increasing Al contents. The VSM results of Al-doped BiFeO 3 (BFO) demonstrate that BFO crystals with size >60 nm show anti-ferromagnetic behaviour, which is evident in the present study. The increase in Al doping results in an increase in coercivity, as grain size and coercivity are inversely related with each other. This is because of the replacement of Fe 3+ by Al 3+ ions, which weakens the sub-lattice interactions. It has been observed that BFO materials with such parameters are favourable for ferroelectric random access memories where data can be written electrically and read magnetically.

February 7, 2020

Theoretical Studies of the Defect Structures for Cu(en)₃²⁺ and Ru(en)₃³⁺ Clusters in Tris(Ethylenediamine) Complexes

Xu-Sheng Liu, Shao-Yi Wu, Meng Han, Qing-Sheng Zhu

Page range: 257-263

Abstract

The local structures and spin Hamiltonian parameters (SHPs, g factors, and hyperfine structure constants) for the Cu(en) 3 2+ and Ru(en) 3 3+ clusters in ethylenediamine complexes are theoretically studied from perturbation formulae for tetragonally and trigonally elongated octahedral 3d 9 and 4d 5 clusters, respectively. Cu 2+ centres I and II may experience the slight relative elongations Δ Z by about 0.005 and 0.007 Å in Zn(en) 3 (NO 3 ) 2 polycrystalline powder at 4.2 K and room temperature, respectively, along the C 4 axis arising from the Jahn–Teller effect. For Ru(en) 3 3+ cluster in the uniaxial [Rh(en) 3 Cl 3 ] 2 NaCl ⋅ 6H 2 O single crystal doped with the single-crystal chloride salt [Ru(en) 3 ]Cl 3 ⋅ 4H 2 O, the local impurity–ligand bonding angle related to the C 3 axis suffers a negative variation Δβ (≈−1.85°) with respect to the host β H in [Ru(en) 3 ]Cl 3 ⋅ 4H 2 O at 4 K. The features of SHPs and defect structures for the Cu(en) 3 2+ and Ru(en) 3 3+ clusters are also discussed in view of the different experimental temperatures.

Thermodynamics & Statistical Physics

December 12, 2019

A Framework for Sequential Measurements and General Jarzynski Equations

Heinz-Jürgen Schmidt, Jochen Gemmer

Page range: 265-284

Abstract

We formulate a statistical model of two sequential measurements and prove a so-called J-equation that leads to various diversifications of the well-known Jarzynski equation including the Crooks dissipation theorem. Moreover, the J-equation entails formulations of the Second Law going back to Wolfgang Pauli. We illustrate this by an analytically solvable example of sequential discrete position–momentum measurements accompanied with the increase of Shannon entropy. The standard form of the J-equation extends the domain of applications of the standard quantum Jarzynski equation in two respects: It includes systems that are initially only in local equilibrium, and it extends this equation to the cases where the local equilibrium is described by microcanononical, canonical, or grand canonical ensembles. Moreover, the case of a periodically driven quantum system in thermal contact with a heat bath is shown to be covered by the theory presented here if the quantum system assumes a quasi-Boltzmann distribution. Finally, we shortly consider the generalised Jarzynski equation in classical statistical mechanics.

About this journal

Objective
A Journal of Physical Sciences: Zeitschrift für Naturforschung A (ZNA) is an international scientific journal which publishes original research papers from all areas of experimental and theoretical physics. Authors are encouraged to pay particular attention to a clear exposition of their respective subject, addressing a wide readership. In accordance with the name of our journal, which means “Journal for Natural Sciences”, manuscripts submitted to ZNA should have a tangible connection to actual physical phenomena. In particular, we welcome experiment-oriented contributions.

Manuscripts considered for publication in A Journal of Physical Sciences: Zeitschrift für Naturforschung A undergo high-level refereeing. Mere formal correctness of a paper is not sufficient for its acceptance. Moreover, articles reporting a merely marginal extension of already existing knowledge are considered unsatisfactory. Instead, the key quality a publication in A Journal of Physical Sciences: Zeitschrift für Naturforschung A should possess is that it makes a genuine contribution to the advancement of its topic.

Topics

Atomic, Molecular & Chemical Physics
Dynamical Systems & Nonlinear Phenomena
Gravitation & Cosmology
Hydrodynamics
Quantum Theory
Solid State Physics & Materials Science
Thermodynamics & Statistical Physics

Article formats
Original research articles, research notes, letters and review articles from all areas of theoretical and experimental physics

Information on submission process

Volume 75 Issue 3

Issue of Zeitschrift für Naturforschung A

Frontmatter

Bifurcation Analysis for Small-Amplitude Nonlinear and Supernonlinear Ion-Acoustic Waves in a Superthermal Plasma

Abstract

Propagation of Waves in a Nonideal Magnetogasdynamics with Dust Particles

Abstract

Delta-Shock Solution to the Eulerian Droplet Model by Variable Substitution Method

Abstract

Solitary Wave with Quantisation of Electron’s Orbit in a Magnetised Plasma in the Presence of Heavy Negative Ions

Abstract

Heat and Mass Transfer of Temperature-Dependent Viscosity Models in a Pipe: Effects of Thermal Radiation and Heat Generation

Abstract

Michelson Interferometric Hydrogen Sulfide Gas Sensor Based on NH2-rGO Sensitive Film

Abstract

Insight into the Structural, Electrical, and Magnetic Properties of Al-Substituted BiFeO3 Synthesised by the Sol–Gel Method

Abstract

Theoretical Studies of the Defect Structures for Cu(en)32+ and Ru(en)33+ Clusters in Tris(Ethylenediamine) Complexes

Abstract

A Framework for Sequential Measurements and General Jarzynski Equations

Abstract

Michelson Interferometric Hydrogen Sulfide Gas Sensor Based on NH₂-rGO Sensitive Film

Insight into the Structural, Electrical, and Magnetic Properties of Al-Substituted BiFeO₃ Synthesised by the Sol–Gel Method

Theoretical Studies of the Defect Structures for Cu(en)₃²⁺ and Ru(en)₃³⁺ Clusters in Tris(Ethylenediamine) Complexes