Abstract. This paper aims to study lump waves formed by nonlinearity and dispersion in a spatial symmetric generalized KP model in (2+1)-dimensions. To an associated Hirota bilinear form of the model equation, positive quadratic waves are computed to generate lump waves by symbolic computation with Maple. It is shown that critical points of the positive quadratic waves are located on a straight line in the spatial space, whose coordinates travel at constant speeds. Optimal values of the corresponding lump waves are explicitly worked out, not depending on time, either. The dispersion terms and the nonlinear terms jointly create the lump waves.

Abstract. By applying a nonclassical method, we have explored the symmetries for a nonlinear partial differential equation, namely, the Benjamin-Ono equation. Furthermore, the power series and ansatz techniques have been implemented for furnishing new forms of exact solutions for the considered equation, consisting of trigonometric, hyperbolic, and polynomial functions, accompanied by multiple free parameters. To enhance the understanding of physical implications, the graphical representations of bell shape, kink, and periodic solutions are shown.

Abstract. For Dirac particle, the general mathematical and numerical study of the tunneling process through the effective potential barrier generated by Schwarzschild black hole geometry is done. The main accent is given to analytical construction of the exact solutions for the problem. The study is based on the use of eight Frobenius solutions of the relevant second order radial differential equations with the complicated structure of the singular points. We construct such solutions in explicit form and prove that the power series involved in them are converged in the whole physical region of the variable: from Schwarzschild radius to infinity. Results for tunneling effect significantly differ for two situations: one when the particle falls on the barrier from inside of the black hole and another when the particle falls from outside. Mathematical structure of the derived asymptotic relations is exact, however their further study is based on numerical summing the convergent series. In calculations, the tools of the Mathematica system are used.

Abstract. In this research, we have delved into the investigation of an integrable extension of the Ito equation in a (3+1)-dimensional space with the aim of discovering novel analytical solutions. Our approach involves the utilization of mathematical tools such as Hirota's bilinear operator and Bell polynomials, to derive the bilinear form of the considered equation. Additionally, we have explored different test functions f in the corresponding bilinear equation, which leads to the emergence of various families of exact solutions accompanied by multiple free parameters. To enhance the understanding of physical implications, the graphical representations of bright solitons and periodic solutions, kink waveforms and interaction solutions, lumps and interaction solutions, and breather solutions are depicted.

Abstract. Radioisotopes have a growing impact in various fields of industry and medicine. Especially in modern medicine, based on the synergies of nuclear physics, radiochemistry, and radiobiology, the demand for more readily available, higher quality, and also new radioisotopes is constantly increasing. As key components of radiopharmaceuticals, they are used in many ways for diagnostics imaging, and treatments of cancer or other health issues. Diagnostics based on the precise positioning of imaging photons have improved due to recent advances in molecular biology. Ongoing intense research of biological vehicles (transporters), such as monoclonal antibodies (mAbs), specific proteins and peptides, or other designed molecules led to new and more precise methods to place specific radioisotopes, exactly there where they are intended. The techniques of targeted therapy were developed, based on the precise delivery of cell-killing radiation directly and specifically to cancer cells, too. Imaging techniques are used not only to diagnose but also to monitor the therapy efficacy and follow-up, using highly selective and specific vectors, allowing for the quantification of essential tumour parameters such as receptor density, proliferation index, or hypoxia. Thus, theranostics, which combines matching radioisotopes of similar elements or, ideally, different emissions of the same radioisotope(s) for treatment and monitoring of the therapeutic response at the same time, became an important tool of clinical practice.

Abstract. In this work, we study the effect of the polymer on the dynamics of extremely short optical pulses in a medium with single-walled zigzag-type carbon nanotubes. Based on Maxwell's equations, taking into account pumping by an external field and nonlinear absorption of nanotubes introduced phenomenologically, an effective equation for the vector potential of the electromagnetic field is obtained. We reveal the dependence of the characteristics of an extremely short pulse on the polymer concentration and other parameters of the problem.

Abstract. Polymers are crucial in a variety of industries; nevertheless, surface modification is required for particular applications. Non-thermal plasma exposure is a viable and environmentally friendly option. Fused deposition molding employs polyethylene terephthalate glycol, but has limits in biomedical applications due to poor mechanical characteristics. This study investigates how atmospheric pressure plasma created by a dielectric barrier discharge system using helium and/or argon affects the modification of polyethylene terephthalate glycol surfaces, variations in wettability properties, and chemical composition alterations. The plasma source was ignited with either helium or argon and the operating conditions were optimized for polymer exposure. The study found that plasma treatment increased polymer surface wettability by up to 30% in helium and 40% in argon. The plasma treatments altered the surface topography, morphology, roughness, and hydrophilicity. After plasma treatment, the material's mechanical characteristics underwent soft change. Plasma exposure resulted in notable changes in dielectric characteristics, phase transitions, and structure. The experimental results justify the use of atmospheric pressure plasma technologies for environmentally friendly polymer material processing, particularly for applications that require enhanced adhesion and unique criteria.

Abstract. Nowadays, the efficiency of Cu₂ZnSnS₄ (CZTS) thin-film solar cells is still limited by various factors such as: electronic disorder, secondary phases and the presence of antisite defects. In order to avoid this limitations, the Zn substitution by heavier atoms like Cd was proposed, as it may inhibit the formation of antisite defects, thereby increasing the minority carrier lifetime and reducing electronic disorder in the system. Thus, the main goal of this work was to investigate the optical properties of Cu₂ZnSnS₄ (CZTS) and Cu₂CdSnS₄ (CCTS) quaternary compounds. Hence, the reflectance, transmittance and photoluminescence spectra were recorded over a wide temperature range (from 10 to 300 K). As a result, for the CZTS sample, the optical band gap energy at room temperature was found to be equal to 1.46 eV. Also, reflectance and photoluminescence spectra at 15 K revealed essential details about the excitonic behavior in the CCTS sample, in particular for the A type exciton, with ground and excited states (n^A = 1 and n^A = 2) observed. The binding energy for the A type exciton was found to be 64 meV, leading to an estimated band gap width (E_g) of about 1.39 eV. In addition, at higher energies, spectra revealed maxima associated with the ground and excited states (n^B = 1 and n^B = 2) of the B type exciton, with an estimated binding energy of 75 meV and a continuum energy of about 1.51 eV.

Abstract. In a series of previous papers we have developed an accurate wave model for molecular systems. In this paper we extend the model to the case of two important effects in biophysics. The first is the van der Waals effect, which leads to the self-assembly of macromolecules, while the second is the transformation of the chaotic molecular system with broken symmetry into a normal symmetric one, by orienting the molecules in the electromagnetic field. These results are in agreement with the experimental data reported in the literature.

Abstract. In an extension of our previous studies of environmental radiological monitoring, the radionuclides activity concentrations (²²⁶Ra, ²³²Th, and ⁴⁰K) were estimated using gamma-ray spectrometry for three soil types (silt clay loam, clay loam, and sandy clay loam) from three diverse regions adjacent to the Nile River in Egypt. These measures were found to be 14 ± 1.34 to 29 ± 2.81, 5.7 ± 0.54 to 23.3 ± 2.34, and 113 ± 11 to 427 ± 41 Bq kg^-1, respectively. We aimed to investigate the correlation between radionuclide concentrations in soils with different textural properties and chemical parameters, such as hydrogen ion concentration (pH) and organic matter (OM). The recorded values for soil pH ranged from 6.9 to 8.2, while the organic matter content ranged from 0.4 to 2.6%. A correlation was observed between ⁴⁰K activity concentration and OM.

Abstract. The environmental problems and solutions represent a priority for scientific community. Water pollution with drugs is a contemporary problem, which needs to be made aware of and solved by ecological means. Also, ecofriendly methods of decontamination of polluted waters are a topic of study for students from natural sciences. The present work proposes an eco-friendly method of filtering drug-polluted water, which can be used in students' experimental laboratories related to environmental protection. This paper presents the use of clay, micronized activated zeolite and granular activated carbon as filters for the removal of drugs from wastewater. Using the UV-VIS spectroscopy technique, the degree of decontamination of water polluted with N-Acetyl cysteine is evaluated. The combination of the three filter materials is the most efficient one having the greatest absorbance capacity of 71%. Students using these methods, besides better understanding the chemical and physical notions related to the experiment, will also learn about sustainability and environmental protection.

Abstract. The effects of the seismic attenuation pattern observed at the bend of the Southeastern Carpathians on the peak ground motions (PGMs) produced by local crustal earthquakes are analyzed using theoretical experiments. The synthetic seismograms ― ground velocity time histories, vertical component ― are calculated by the multimodal summation method in layered inelastic media. The theoretical waveforms evidence that the lateral variations of the attenuation structure may result in higher peak amplitudes at larger epicentral distances, in other words, the wave attenuation may dominate the wave spreading in the study area, within epicentral distances up to a few tens of km. The result is in good agreement with the observations, and emphasize the substantial contribution of the crustal attenuation to the pattern of ground motions caused by crustal, as well as intermediate-depth earthquakes of Vrancea.

Abstract. In this paper we discuss how the use of new educational technologies into the learning process may act as a factor of inspiration and motivation for high-school students to pursue a career in science and engineering. Using materials easy to obtain the simplicity of the Arduino microcontroller and the open-source community, we have developed a series of tools that can be used in physics experiments with the aim to encourage the study of sciences. In addition, the corroboration between the principles of accessibility of knowledge and of combining theory with practice is the guarantee of effective learning.