Band 79, Heft 5

Dispersive characteristics of electromagnetic sound waves with frequencies less than the electron and ion gyro-frequencies are studied herein analytically and numerically at astrophysical scales. Magnetic quantization of Fermi states is concerned with the degenerate relativistic electrons fluid treated by quantum hydrodynamic model (QHD). The quantum features are included from Landau quantized Fermi pressure dependent upon the dc magnetic field, whereas the ions are treated as nondegenerate and classical. The numerical analysis verifies the analytical results. The phase speed of magnetosonic waves for relativistic degenerate plasma typically for white dwarf stars parameters is depicted from the graphical figures. In this manuscript, an overlooked feature of quantization, that is Landau quantization, is mainly focused for magnetoacoustics in plasmas.

Local structures and electron paramagnetic resonance (EPR) parameters ( g factors g x , g y , and g z ) for the substitutional Ti 3+ and W 5+ centers in stishovite are theoretically investigated by using the high-order perturbation formulas of these parameters for a d 1 ion in rhombically compressed octahedra. In the calculation formulas, the related molecular orbital coefficients are obtained from the cluster approach, and the relevant crystal-field (CF) parameters are determined from the superposition model, which enables to connect these CF parameters and, hence, the studied g factors with the local structures of the Ti 3+ and W 5+ centers in stishovite. Based on the calculations, the impurity–ligand bond lengths parallel and perpendicular to the C 2 -axis are found to be R ′ || (≈1.751 and 1.717 Å) and R ′ ⊥ (≈1.788 and 1.806 Å) with the planar bond angles θ ′ (≈89.0° and 88.2°) for the studied [TiO 6 ] 9− and [WO 6 ] 7− clusters, respectively. The calculated results are in good agreement with the experimental data, and the validity of the results is discussed.

The structure of viscous shock-front has been investigated in a van der Waals gas between the boundary conditions for x = − ε and x = + ε considering the flow of a gas to be viscous and one-dimensional. The exact solutions for the flow parameters, fluid velocity, pressure, temperature, and change-in-entropy in the shock transition region have been found in view of the equation of state for van der Waals gases. The effects due to the coefficient of viscosity, shock strength, and nonidealness parameter have been analyzed on the structure and flow variable in the shock transition region. The results confirm that the thickness of shock-front increases with increasing value of the coefficient of viscosity and decreases with increasing value of the shock strength and nonidealness parameter of the gases.

In this paper, we study traveling wavefronts in an anomalous diffusion predator–prey model with the modified Leslie–Gower and Holling-type II schemes. We perform a traveling wave analysis to show that the model has heteroclinic trajectories connecting two steady state solutions of the resulting system of fractional partial differential equations and corresponding to traveling wavefronts. This also includes numerical results to show the existence of traveling wavefronts. Furthermore, we obtain the numerical time-dependent solutions in order to show the evolution of wavefronts. We find that wavefronts exist that travel faster in the anomalous subdiffusive regime than in the normal diffusive one. Our results emphasize that the main properties of traveling waves and invasions are altered by anomalous subdiffusion in this model.

In this article, a partial differential equation (PDE) model for atherosclerosis disease is presented that analyzes the anti-oxidative activity of high-density lipoprotein (HDL) during the reverse cholesterol transport (RCT) process. The model thoroughly investigates the complex interplay between oxidized low-density lipoprotein (ox-LDL) and high-density lipoprotein in the context of atherosclerosis, emphasizing their combined impact on plaque formation, disease progression, and regression. In addition to this, we considered that monocytes are also attracted by the presence of ox-LDL within the intima. Detailed discussions on stability analyses of the reaction dynamical system at non-inflammatory and chronic equilibrium are provided, followed by a bifurcation analysis for the proposed system. Furthermore, stability analysis for the PDE model in the presence of diffusion is conducted. Our study reveals that the oxidation rate of LDL by monocytes ( δ ) and the influx rate of HDL ( ϕ ) due to drugs/diet are primarily responsible for the existence of bi-stability of equilibrium points. In the numerical results, we observe that non-inflammatory or chronic equilibrium points exist for either a short or a long time, and these findings are validated with existing results. The biological elucidation shows the novelty in terms of enhancing our ability to assess intervention efficacy to generate therapeutic strategies resulting in the reduction of the atherosclerotic burden and associated cardiovascular risks.

The neutron capture rates and Maxwellian-averaged cross-sections (MACS) for 90 Zr( n , γ ) 91 Zr and 92 Zr( n , γ ) 93 Zr processes have been computed within the framework of Talys v1.96. The effects of phenomenological nuclear level density (NLD) parameters and the gamma strength functions (GSFs) on Maxwellian-averaged cross-sections and neutron capture rates are examined both quantitatively and qualitatively. The present model-based computed data for MACS and reaction rates gives a good comparison with the existing literature. The fine-tuning of the statistical model’s nuclear properties (level density and gamma-ray strength) to reproduce experimental data will allow the detailed investigation of the s -process network.

In classical physics, there is a basic principle, namely “A particle cannot be located at the position of another one on the same time.” Which consequences can be derived if this principle is transferred into quantum physics? For doing that, two distinguishable particles are considered to be trapped in a potential box by means of the Schrödinger equation. In result, the particles can necessarily be located only at discrete positions.

The various structural and conductive attributes of barium cerate, BaCeO 3 position it as a highly promising matrix for energy storage purposes. The current study illustrates that barium cerate can be effectively tailored by introducing trivalent praseodymium ions, thereby enhancing its optical properties as well. In this work, single-phased orthorhombic crystalline powders of barium cerate incorporated with Pr 3+ (BaCeO 3 : Pr 3+ ) were synthesized using the gel combustion procedure, followed by calcination. We conducted a comprehensive investigation into their crystal structure, vibrational characteristics, optical properties, and potential applications in wLEDs. The structure refinement indicates that Pr 3+ occupies Ce 4+ site, which results in the expansion of the cell and facilitates the generation of defects such as Pr Ce ′ ${\mathrm{Pr}}_{\text{Ce}}^{\prime }$ and oxygen vacancies V O ⋅ ⋅ ${V}_{\text{O}}^{\cdot \cdot }$ . By correlating information gathered from diffuse reflectance spectra with that obtained from photoluminescence spectra, we gained a deeper understanding of the electronic level structure and the mechanism of energy transfer. We successfully achieved a finely tuned cool white light emission with very low color purity (CP), a high color rendering index (CRI), and a high correlated color temperature (CCT) with a quantum efficiency of 36.3 % by exciting the material with a 321 nm wavelength. Because of the transfer of energy within activators through dipole–dipole interaction, luminescence quenching occurs when Pr 3+ concentration reaches 1 wt%. To the best of our knowledge, this is the initial investigation of luminescence properties of Pr-incorporated barium cerate perovskites.

This study investigated the effects of CuAl 2 O 4 (CuAl) on four types of spinel ferrites: CoFe 2 O 4 (CoF), NiFe 2 O 4 (NiF), MgFe 2 O 4 (MgF), and ZnFe 2 O 4 (ZnF) with regards to their electrical characteristics and microscopic magnetic behavior. According to the Seebeck coefficient ( φ ), the nanocomposites have a mixture of positive and negative charge carriers, except for CoF/CuAl, which has a positive charge carrier only. Depending on the temperature, the DC conductivity of all MF/CuAl nanocomposites has a conductor and semiconductor behavior. The dielectric properties were studied at different frequencies (100–10^8 Hz) and temperatures (300–673 K). The results demonstrated how temperature and frequency affect AC operating mechanisms. The high values of dielectric loss for all nanocomposites confirm their applicability in high-frequency microwave devices. The impedance study revealed that the equivalent circuit for all MF/CuAl nanocomposites is a mixture of R, L, and C. Temperature-magnetization graphs were obtained for all nanocomposites, indicating ferrimagnetic behavior except ZnF/CuAl. The magnetic transition temperature ( T Cm ), the Curie–Weiss constant ( θ CW ), and the effective magnetic moments ( μ eff ) for all nanocomposites were determined. The MF/CuAl samples were analyzed using ESR spectroscopy at room temperature. The spectra were distorted but remained distinct, potent, and sweeping. The g -factor values deviate from the free electron, which suggests that the Fe 3+ –O–Fe 3+ superexchange interaction has changed. In addition, the interaction effect between MF and CuAl is discussed.