Samarkand State University

In this study, multifunctional PVA–SA-based nanofibers incorporating cerium hexaboride (CeB₆) nanoparticles and MXene (Ti₃CNTₓ) were successfully fabricated via electrospinning to develop advanced dielectric and thermally stable materials. Structural and morphological analyses confirmed the homogeneous integration of both fillers within the polymer matrix while preserving fiber integrity. The synergistic interaction between CeB₆ and MXene played a critical role in enhancing interfacial polarization, charge transport, and thermal resistance. MXene incorporation increased the maximum degradation temperature from 311 °C to 327 °C, while significantly improving dielectric performance, with ε′ values reaching 15–16 at higher loadings. In addition, capacitance values nearly doubled, indicating enhanced energy storage capability. Mechanistically, MXene sheets facilitated the formation of conductive pathways and strong interfacial dipolar interactions, whereas CeB₆ served as a stabilizing phase and a charge-trapping center. This hybrid interaction resulted in reduced impedance and improved frequency-dependent electrical behavior. Overall, the developed CeB6–MXene/PVA–SA nanofibers exhibit tunable surface characteristics and enhanced multifunctional performance, making them promising candidates for flexible electronics, dielectric layers, sensor platforms, and energy-related applications.

The study responds to the paradigm shift that is taking place within the concept of sustainable tourism development. The so-called "regenerative shift" moves the goals of its development from minimizing impacts on sociocultural-ecological systems (SES) towards the ability of tourism to contribute to the improvement and restoration of SES. Many authors consider it a significant paradigm shift, which they also refer to as a separate line of development outside sustainable tourism. Although there are already relatively solid theoretical frameworks for the concept of regenerative tourism, it has not been sufficiently developed in the area of cultural heritage restoration. This study responds to this gap by applying a regenerative framework to a specific case of a historical building-the wooden church of Sf & acirc;ntul Gheorghe in Prod & abreve;nesti, Romania. The aim of the research is to empirically assess the extent to which the microclimatic and environmental conditions of the building are compatible with the principles of regenerative cultural heritage management and how they affect its physical integrity and usability in the context of local tourism and community needs. Methodologically, the study is based on long-term monitoring of the internal microclimate, which took place between August 2024 and January 2025. The subject of monitoring was the measurement of temperature, relative humidity, particulate matter PM2.5 and PM10, volatile organic compounds, light intensity, acoustic intensity, negative and positive ions. Within the research, biological degradation factors (lichens, microorganisms) were examined, and the research was supplemented by a non-invasive investigation using infrared thermography to capture the momentary condition of the surface temperature and interior painting in the wooden church, which is in a state of significant decay.The results show a significant exceedance of the recommended temperature and relative humidity values, a high dependence of the interior environment on external climatic conditions, and the presence of biological degradation processes that negatively affect the authentic building materials and preserved fragments of interior decoration. It transpires that the physical degradation of the building is not an isolated technical problem, but a manifestation of the broader dynamics of the SES within cultural heritage management. Recommendations include the introduction of continuous microclimatic monitoring, the application of non-invasive conservation measures. The proposals include adaptive management, which combines data-driven decision-making with community participation, and enables flexible responses to the SES dynamics of cultural heritage systems.

This paper studies the motion and interactions of particles with magnetic dipole moments in the vicinity of magnetized black holes in the braneworld model. The analysis begins by solving Maxwell’s equations for the electromagnetic potentials in the presence of an external uniform magnetic field, incorporating the brane parameter’s influence on the field’s radial and angular components. The effective potential governing particle dynamics is derived, and expressions for the energy and angular momentum of circular orbits are obtained. Particular attention is given to the role of the tidal charge and magnetic interaction parameter in determining the location and stability of circular orbits. The innermost stable circular orbit (ISCO) is examined in detail, showing that an increase in the brane parameter shifts the ISCO inward, while a stronger magnetic interaction pushes it outward. The study also explores collisions of magnetized particles near the black hole horizon. Conditions for critical angular momentum are identified, highlighting the thresholds that separate bound orbits from plunging or escaping trajectories. The center-of-mass energy of the colliding particles is then computed, revealing how both brane effects and magnetic interactions affect it. The results demonstrate that while braneworld corrections enhance collision energies, strong magnetic coupling suppresses them, thereby moderating the unbounded values predicted in simpler models. These findings offer new insights into the dynamics of magnetized matter near black holes, providing potential observational signatures relevant to high-energy astrophysical processes, such as accretion flows, cosmic-ray acceleration, and the formation of relativistic jets.

Glass fiber-reinforced polymer composite bolted structures, as an all-composite connection method, offer significant weight reduction advantages. However, the structural failure caused by preload attenuation has become a major safety hazard threatening engineering applications. To address this issue, this study proposes a novel method for structural health monitoring of composite bolted joints based on a washer-type buckypaper (BP) sensor. The feasibility and load variation synchronization of this new washer-type BP sensor for monitoring bolt preload changes were verified through multistage continuous loading-unloading comparative tests. Static tensile tests, vibration characteristic tests, vibration tests under different acceleration levels (20, 40, 60, and 80 g), vibration fatigue tests (58,000 cycles), and simulated loosening tests were conducted on composite bolted joint specimens equipped with this new washer-type BP sensor. The results demonstrate that the sensor exhibits excellent load response synchronization, high sensitivity, and outstanding stability. It enables in situ monitoring of preload force in composite bolted structures, providing real-time response to preload variations under both static and dynamic loading conditions. This offers a novel solution for full-life cycle loosening health monitoring of composite bolted joints.

The study of the geometric properties of analytic functions and their numerous applications in a variety of mathematical fields, including fractional calculus, probability distributions, and special functions, has drawn significant and impressive attention to Geometric Function Theory (GFT), one of the most prominent branches of complex analysis, in recent years. The focus of this article is to introduce a new subclass of analytic functions involving Bell Distribution series and obtain coefficient inequalities, neighborhood results and partial sums for this class.