Volume 80, Issue 5

This study employs RF magnetron sputtering to prepare and pure thin films of indium tin oxide (ITO), exploring both its pure form and its augmentation with iron (Fe) doping. The influence of Fe on these films was thoroughly scrutinized using diverse characterization approaches, including thermoelectric evaluations, X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible spectroscopy, and Hall measurements. XRD confirmed the cubic crystal structure, while SEM imaging revealed a distinctive granular like arrangement. The optical results (Tauc plot) revealed a narrowed bandgap (3.80 eV–3.67 eV) and diminished optical transmission in the visible spectrum owing to Fe doping. Electrical analysis revealed enhanced carrier availability, yielding a significant drop in thin film resistivity to 4.7 × 10 −5  Ω cm at an Fe concentration of 50 W. However, a increased Fe content leads to increased carrier density and resistivity. The mobility decreases, and the Seebeck value diminishes with increasing carrier concentration and Fe content. Remarkably, at 20 W Fe power, the thermoelectric power factor peaks at 0.73, aligning with a resistivity of 7.18 × 10 −5  Ω cm. These compelling findings, spanning the optical, structural, electrical, and thermal dimensions, emphasize the prospective utility of these materials in thermoelectric and photovoltaic systems.

This study presents the design and optimization of a graphene–gold–silver metasurface sensor for the highly sensitive detection of organic compounds in the terahertz (THz) regime. By leveraging the plasmonic properties of gold and silver combined with the tunable electronic characteristics of graphene, the sensor demonstrates enhanced molecular interaction and improved detection performance. COMSOL Multiphysics simulations show a high refractive index sensitivity up to the value of 810 GHzRIU −1 and excellent resonance characteristics with a quality factor (Q) of 11.197. The sensor achieves a detection limit (DL) as low as 0.075 RIU and a dynamic range (DR) from 2.765 to 2.555, indicating exceptional sensitivity and broad applicability. Additionally, the integration of machine learning optimization, particularly Locally Weighted Linear Regression (LWLR), improves prediction accuracy, achieving a value of R 2 near to 1. The results highlight the sensor’s real-time, label-free detection capabilities, with a signal-to-noise ratio (SNR) up to the value of 0.377. These findings demonstrate the sensor’s potential for applications in environmental monitoring, biomedical diagnostics, and industrial quality control, offering a significant advancement in THz-based sensing technologies.

Modern spacecraft missions reveal the decomposed form of electrons in the expanding solar wind. Non-thermal features in the form of temperature anisotropy ignite the various instabilities and define the dynamics of plasma systems. In the rare-collisions scenario, such instabilities play a dominant role to keep thermodynamic equilibrium states of charge particles. The dispersion characteristics (growth rate and instability domain) of purely growing ( ω r = 0) combined electron-ion mirror instability in the linear and quasilinear phases of instability evolution are presented. Mirror instability appears for large perpendicular temperature condition i.e. T ⊥ > T ‖ in the relatively high plasma beta regimes. Based on in situ measurements, we assume bi-Maxwellian forms of ions, core and halo electrons components in which the initial temperatures are allowed to vary in time t . Employing a moment-based quasilinear theory, a set of self-consistent equations have been derived which comprised dispersion relation, dynamical temperatures relations, and wave-energy density equation. During the time-evolution of combined electron-ion mirror instability, the growth rate keeps falling and associated wave-energy density rises concomitantly. Initial large temperature anisotropy ratio of ions, core and halo electrons favor the relaxation/saturation of initial distribution and wave-intensity due to more available free energy for the peak growth rate/wave-energy density. Further, a time variation in the halo electrons population in the radially expanding solar wind put a notable impact on combined ions-electrons instability evolution. Higher values of halo electrons density favors growth rate, wave-energy density, and an early relaxation of ions and electron distribution.

To understand the nonlinear behavior of the dust acoustic solitary waves (DASWs) and the production of rogue waves (RWs) in the Jupiter environment at distances greater than 15 R J , a five-component relativistic dusty plasma system comprising positive dust particles, streaming positive ions, isothermal ions, electrons, and solar wind electrons has been considered. To analyze this system, the Korteweg–de Vries (KdV) equation is derived using the reductive perturbation method (RPM), and the nonlinear Schrödinger equation (NLSE) is derived by employing the derivative expansion method. Both analytical and numerical (Adomian decomposition scheme) solutions of the KdV equation are studied. It is found that the nonlinearity and amplitude of dust-acoustic solitary waves (DASWs) as well as the width of the electric field structure increase, while the rogue wave (RW) amplitude decreases with the growing effect of the relativistic streaming positive ion factor. The analytic solution of the KdV equation provides only the rarefactive DASWs, while its numerical solution gives both compressive and rarefactive DASWs. This investigation may help not only to comprehend the space plasma phenomena, particularly in the Jupiter atmosphere, but also to validate laboratory investigations where concerned plasma species are present.

This work calculates the transmittance spectrum in a one-dimensional photonic crystal formed by alternating silicon/germanium layers with Si 1− x Ge x doped defects. Using the transfer matrix method, we calculate transmittance by analyzing the dependence on structural factors such as layer thickness, relative location between defects, and germanium concentration. The results show the existence of localized modes inside the photonic band gap, which exhibit a redshift in wavelengths with increasing material concentration and constant thickness. When the number of layers separating two defects is increased, keeping both the germanium concentration and the thicknesses fixed, the localized modes exhibit a degeneracy that disappears and originates a splitting of the spectral lines if the distance separating the defects is small. This work will contribute to the field of silicon-based optical devices.

This study considers the buckling problem of beams resting on a nonlocal foundation. A nonlocal foundation is modeled with two different spring structures extending under and along the length of the beam and a shear layer between these springs. This study investigates the buckling of a beam on the nonlocal foundation using a method based on the Fourier sine series and Stokes’ transformation. Thus, an analytical solution of a beam on a nonlocal foundation modeled by transverse springs at both boundaries is presented. This solution can solve arbitrary, i.e., rigid and non-rigid, boundaries since it includes the stiffnesses of the transverse springs positioned as bearings at both ends of the beam resting on the nonlocal foundation. The stiffnesses of the springs at the ends of the beam can be set arbitrarily and the effects of numerous boundary conditions, whether rigid or deformable, can be studied. After the derivation of the solution formulation, the effects of different parameters on the critical buckling loads of beams resting on nonlocal foundations are investigated through a series of numerical examples.

The primary aim of this study is to promote the widespread adoption of Fe–Si–C-based amorphous ribbon samples and contribute to reducing power losses in energy transmission processes by offering new practical solutions. Amorphous ribbon samples with the composition Fe 92 Si 6 C 2 were prepared. The structural and magnetic properties of these materials were studied within the framework of the Random Anisotropy Model (RAM). The obtained results were compared with those of electrical steel. The high electrical resistance, favorable magnetic properties, and corrosion resistance of the amorphous samples make them advantageous for various applications. Using the methods and processing regimes outlined in this study, contactor cores were manufactured from Fe 92 Si 6 C 2 amorphous ribbons. During the experiment, the cores of a 3SC8-A122 model alternating current contactor operating at 220 V, produced by Sassin, were replaced with new cores made from the studied Fe 92 Si 6 C 2 amorphous ribbons, and industrial trials were conducted. The trials demonstrated that the application of E-cores made from amorphous ribbons enables the production of more economically advantageous contactors.