Within the scope of Bianchi type-$II$ cosmological model we have studied the role of spinor field in the evolution of the Universe. It is found that in this case the components of energy-momentum tensor of spinor field along the principal axis are different, i.e. $T_1^1 \ne T_2^2 \ne T_3^3$, even in absence of spinor field nonlinearity. The presence of nontrivial non-diagonal components of energy-momentum tensor of the spinor field imposes severe restrictions both on geometry of space-time and on the spinor field itself. Depending on the choice of $f(x_3)$ the space-time might be either locally rotationally symmetric or isotropic. In this paper we considered the Bianchi type-$II$ space-time both for a trivial and nontrivial $b$. It was found that while a positive $\lambda _1$ in case of $f^\prime \ne 0$ gives rise to oscillatory mode of evolution, in case of $f^\prime = 0$ it leads to accelerated mode of expansion.

In this work, two novel integrable extensions to the Vakhnenko-Parkes equation (eVPE), namely, extended eVPE1 and eVPE2 as well as extended modified VPE1 (emVPE1) and VPE2 (emVPE2) are introduced and analyzed. In a like manner, we establish another two integrable extensions to the modified Vakhnenko-Parkes (eMVP) equations. We justify that every new extension of the newly developed equations are complete integrability using Painlevé test (PT). We examine the dispersion relations and the necessary condition for the existence of multiple soliton solutions (MSSs) to this family of the Vakhnenko-Parkes equation. We employ the simplified Hirota's method (HM) for solving this family and deriving the MSSs.

We investigate the chaotic dynamics of the relative phase between two coupled Bose-Einstein condensates with small fractional population imbalance. Based on the two-mode approximation, the system equation can be expressed as that of a Josephson junction with a ratchet potential. A general solution of the first order perturbed equation for the symmetric case is theoretically constructed. From the boundedness condition of the general solution we analytically obtain the Melnikov chaotic criterion predicting the onset of chaos in the system. Numerical simulations show that the relative phase can be a constant in some parameter spaces. That means the system is in a simple or regular state. It is also numerically demonstrated that adjusting the time-dependent nonlinear interaction for the symmetric case and the trap asymmetry parameters for the asymmetry case, respectively, can force the relative phase to step from periodic states into chaotic ones via period doubling route.

Two point charges are placed in a spherical dielectric core-shell embedded in a dielectric environment, one of the charges being located in the core and the other in the shell. The core, shell, and environment are characterized by different dielectric constants. Analytical solutions for the electrostatic energy of the system and the polarization charge density at the core-shell and shell-environment interfaces are obtained by a classical approach.

This paper presents the synthesis of the polymeric surface radioactive sources for beta radionuclide characterization based on radio-induced tritium-styrene grafting onto polyethylene terephthalate thin foils. The Quantum chemical methods and Electronic Spin Resonance spectrometry were used to analyse radiolysis phenomena in the polymeric base and labelled polystyrene. The unlabelled polystyrene was irradiated using a Co-60 radioactive source. A quantitative analysis for radio-induced effects on unlabelled styrene was performed using Fourier Transformer Infrared Spectrometry and Atomic Force Microscopy, the grafting yields was determined using radiometric methods reported to tritium labelled styrene standards. The total activity and uniformity of radioactivity distribution of these polymeric surface sources was analysed using a Beta Thin Layer Chromatographic System.

Planar and core-shell structures prepared on the basis of semiconductor nanowires with various semiconductor films constitute a basis for a wide variety of devices for multiple applications. Planar structures have been prepared in this study by atomic layer deposition (ALD) of ZnO and TiO₂ thin layers on semiconductor substrates, and their morphologies and the luminescence properties have been compared with those of coaxial core-shell structures obtained by coating of GaAs nanowires with ZnO and TiO₂ shells. The prepared structures have been characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and X-ray diffraction (XRD) analysis, and photoluminescence (PL) spectroscopy. Polarization characteristics of PL bands related to different recombination channels have been investigated in core-shell structures, and the results were analyzed in terms of the either contrast in dielectric constants, or selection rules associated with crystal structure symmetry, or local strain related to specific microscopic structure of recombination centers involved in electronic transitions responsible for specific PL bands.

This work, deals with the effect of various Cu/LiF, Cu/MgO, and Cu/Si coated systems on the change in the plasticity index H/E and the resistance index H³/E² under indentation in a wide range of loads P_max = 5–900 mN. The main parameters of elasticity, strength and plasticity were determined, as well as the values of H/E and H³/E². The general and specific features of the coated systems deformation under the action of a concentrated load were revealed. The deformation structure of the coated systems was examined at the dislocation level, which made it possible to establish the response mechanism of the CSs to the action of an external load and to explain the specific nature of the plastic and strength properties of the composite systems of “soft film/soft substrate” and “soft film/hard substrate” types.

The dependence of quasi-Fermi levels and current-voltage characteristics of electrons and holes of two-dimensional diodes with a p-n-junction on the wavelength of light was theoretically studied. The results obtained were compared with the experimental results. Theoretically, the differential conductivity and diffusion capacitance of a threedimensional p-n-junction diode (3D) is shown to be relatively larger than that of a twodimensional diode (2D).

Silica materials (without and with TiO₂ nanoparticles) were synthesized via sol–gel route in the presence of different silane precursors. Hybrid films have been produced by deposition of these materials on glass substrates. Physicochemical and optical properties of final materials were characterized by Fourier Transform Infrared Spectroscopy (FTIR), UV–Vis Spectroscopy, Thermogravimetric Analysis (TGA) and Contact Angle (CA) measurements. The interactions between silica material and TiO₂ nanoparticles were confirmed by FTIR. TGA analysis showed that the introduction of TiO₂ nanoparticles into silica material improved its thermal stability and reduced weight loss rates. Diffuse reflectance spectra revealed that the hybrid films present antireflective property (R ~ 7%). From contact angle measurements, it was found that the obtained hybrid films present a different wetting ability. The final materials could be used to enhance the performance of photovoltaic devices.

In this paper, using the study of changes in the statistics of small-scale fluctuations of the probability density during measurements of three components of the magnetic field, we consider short-term precursors for an earthquake with a magnitude of 6.4 that took place on the island of Crete on October 12, 2021 at 9:26:03 UTC, as well as for related foreshocks and aftershocks. The technique used made it possible to identify the indicated precursors of the considered seismic events from several minutes to half a day before their onset. A significant increase in the number of such precursors before the main earthquake was found, as well as the possible existence of a structured sequence of seismic processes at the final stage of preparation of the events under study.

Seismicity clustering characterizes the seismic process. We compute the fractal dimension for the Vrancea earthquakes recorded between 1995 and 2008, both in the crust and in the mantle. The fractal dimension shows a visible decreasing anomaly preceding the largest M_w = 6.0 earthquake in the dataset occurred on 27^th of October 2004.

This paper presents the work accomplished by the IFIN-HH Training Centre within its participation in the ANNETTE EU Project, Horizon 2020 Research and Innovation Programme, in elaboration and delivery of the course entitled: Principles of Radiation Protection and International Framework. Regulatory Control as an interactive e-Learning one. The course contained two parts, the first one regarding the basic information on radiation protection and measures to be applied the practical work with ionizing radiations and the second part presenting the international and national framework of regulations applicable in the field. A final evaluation test for participants was conceived, such as to reflect all the important information within the course. The test was formulated as multiple choice questions, with several possible responses. A statistical analysis of the training results is based on the evaluation of the responses received from the participants at the training program.

The proportional-integral control is the most used algorithm implemented in standard cruise control systems, a robust performance being available only in case of a proper setting of the gain parameters. Therefore, this paper presents a new methodology to establish the proportional coefficient based on signals analyzed in the frequency and time-frequency domains. A complex vehicle model is defined in TruckSim, while the controller model is implemented in Simulink. For different vehicle running scenarios, the co-simulation provides good results and proves to be a good solution as external controller not only for TruckSim, but also for other automotive design software.

Wood has a very high specific strength due to its low density and reasonable strength. However, wood is dimensionally unstable due to variable water content. Its strength varies as well; it decreases with increased water content. Another important mechanical property of wood is its damping capacity which influences significantly the acoustic properties of wood. This capacity is a complex function of temperature and moisture content. The change of damping under load and varying moisture content is rarely studied, although sufficient knowledge of it would drive targeted material substitution of environmentally harmful materials with wood. The amplitude-dependent damping of old (~ 130 years old) and new (< 10 years after felling) spruce wood was measured using dynamic mechanical analysis (DMA) which is a characterisation method that was applied to study the behaviour of both spruce woods under different moisture contents and at different temperatures. The damping of both woods showed a strain-independent and a strain-dependent range. The temperature-dependent damping curves were very similar. Only in old spruce wood a significant dependency on moisture was observed.

In this paper is described the method and process for the development of an online 3D viewer dedicated for displaying time lapse series of imaging data fused with the color texture of a 3D digitized surface. For a better understanding of the whole process and requirements for the repeatability of this experiment, the data acquisition and processing are also included. The paper details the importance of thermal imaging in Cultural Heritage investigation and its advantages for a correct assessment of the conservation state for different types of cultural goods. The concept of timelapse thermography is not new, but still greatly overlooked today. The presented application is a viable solution as a visualization and interpretation tool for large sets of imaging data, as it would result from timelapse series. For testing purposes an afresco experimental panel, with known hidden defects, was used in exterior conditions for timelapse thermography. Data acquisition and preparation for both imaging and 3D digitization are detailed in regards with the requirements the online accessibility.