Urgench State University

This study presents a comprehensive analysis of the mineralogical composition of marl samples from the Meshkli mine using modern analytical methods. By employing combined X-ray diffraction and thermogravimetric analysis (TGA), complemented by high-resolution differential scanning calorimetry (DSC), we identified four distinct periods within the TG and DSC curves. Each of these periods is characterized by specific thermal effects, providing critical insights into the presence of hygroscopic water, combustion of organic compounds, oxidation of iron compounds, and thermal decomposition of calcite. Additionally, X-ray analyses reveal a variety of minerals, including calcite, quartz, montmorillonite, kaolinite, and hematite. These findings significantly enhance our understanding of the mineralogical aspects of the Meshkli mine marls. The purpose of this work is to investigate the physicochemical characteristics of Meshkli mine marl, which is novel for the silicate industry, and to assess its suitability for use in cement compositions. Macroscopically, the marl samples from the Meshkli mine exhibit a green color with yellow and brown spots. They consist of dense rock composed of finely dispersed calcite, clay minerals, and siltstone quartz grains. Chemical analysis indicates that Meshkli mine marl has a homogeneous chemical composition.

In this study, we explore the structural and stability properties of anisotropic dark matter stars within the framework of gravity’s rainbow. By incorporating energy-dependent rainbow functions into the spacetime metric, we examine quantum gravitational effects on compact stars under extreme conditions. Utilizing a modified Tolman–Oppenheimeer–Volkoff (TOV) formalism, we derive exact analytical solutions and perform numerical simulations to investigate the impact of anisotropy and rainbow parameters on stellar mass, radius, and compactness. Our analysis includes stability criteria such as the static stability condition, adiabatic indices, and sound speed causality, highlighting the dynamic behavior of these stars. The findings reveal that gravity’s rainbow allows for more massive and stable compact stars compared to General Relativity, offering insights into quantum gravitational corrections and their astrophysical implications.

In this paper, we investigate the unique solvability of a generalized Tricomi problem with an integral condition for a loaded equation involving a fractional operator. By analyzing the problem for a third-order equation with a telegraph operator, we extend the results to a generalized operator with small parameters. Furthermore, the integral condition in the parabolic region enables the generalization of local problems associated with second- and third-order equations.

In this paper, we investigate the thermodynamics and phase transitions of asymptotically anti-de Sitter black holes (BHs) in the presence of ModMax nonlinear electrodynamics (NLED) and perfect fluid dark matter (PFDM). Combining the effects of ModMax theory, characterized by the nonlinearity parameter $\gamma$ γ , and PFDM, described by the parameter $\alpha$ α , we derive an exact solution for the BH metric and analyze its thermodynamic properties. We explore the critical behavior of the BHs by studying the Hawking temperature, heat capacity, and Gibbs free energy. The results demonstrate the existence of phase transitions analogous to those found in van der Waals fluids, with the ModMax parameter and dark matter playing crucial roles in modifying the critical points and stability of the BH. In addition, we employ geometric thermodynamic methods (GTM), including the Weinhold, Ruppeiner, and HPEM metrics, to further examine the stability and phase structure of BHs. Our study provides new insights into how NLED and dark matter are interrelated within BH thermodynamics.

The urgent need for sustainable transportation has highlighted the integration of solar photovoltaic (PV) panels into electric vehicle (EV) charging infrastructure. This review examines the benefits, challenges, and environmental impacts of this integration. The paper begins by exploring the role of large‐scale solar electric vehicles, featuring cost‐effective, flexible thin‐film solar cells embedded in vehicle body panels. Extensive simulations in various climates demonstrate their potential to address EV charging concerns, reduce range limitations, and manage intermittent energy generation. The review then focuses on Japan's leadership in renewable energy, analyzing the integration of PV power into future electricity systems. Scenario analysis reveals the synergy between renewables, EVs, and heat pumps, supported by smart control strategies, indicating a sustainable energy future for Japan. The final analysis shifts to the Netherlands, where integrating PV panels with workplace EV charging shows promise both economically and environmentally. Economic assessments confirm the feasibility of this approach, supported by installation methods and feed‐in tariffs. Overall, the review highlights the transformative potential of solar PV integration in EV charging infrastructure while acknowledging technical and grid integration challenges. It calls on researchers, policymakers, and industry stakeholders to collaborate in advancing sustainable, efficient, and environmentally friendly urban transportation systems.

The paper presents a study aimed at developing high-strength masonry mortars using ultra-dispersed active mineral additives derived from technogenic raw materials in Uzbekistan. The primary objective is to enhance the adhesion strength between the mortar and silicate bricks, thereby facilitating the industrialization of construction in seismic regions and expanding the application of silicate bricks in masonry. The research focuses on utilizing mineral and man-made resources available in Uzbekistan, as well as incorporating waste products from the building materials industry and construction sites to improve technical and economic indicators.

The purpose of these studies is to study the patterns of development of the characteristics of multiply charged ions in the plasma generated during the interaction of laser radiation with a target operating in the frequency mode. The characteristics of multiply charged ions in monoelement aluminum plasma were studied using laser time of flight mass spectrometers. By changing the laser radiation power in the range from 0.1 to 100 GW/sm² and different pulse repetition frequencies (1, 3, 5, 10, and 12 Hz), spectra of charged ions of the plasma formed in each case were obtained.

Laser fluence-dependent laser-induced periodic surface structures (LIPSS) on niobium alloys was analysed. Additionally, we explored the shift from LIPSS to self-organized, periodic microstructures resembling cones. The findings shed light on how surface structures in niobium evolve depending on laser fluence. Significantly influence of laser fluence to the gradual transition of low-spatial frequency LIPSS to highfrequency spatial LIPSS was demonstrated. Highly organized LIPSS on the surface of targets was obtained at the higher accumulated fluence of laser pulses.

We conducted a qualitative study to explore the often-overlooked experiences of women and their displacement following the 2022 flood catastrophe in Punjab, Pakistan. Given the region's low literacy rate, data were collected from 30 women through extensive interviews using purposive sampling to document participants' subjective evaluations. Thematic analysis revealed that the floods significantly impacted women’s mental health. Despite these challenges, they continue to live with hope. Why? Findings indicate that individual resilience, religious beliefs, and psychological strength play a crucial role in fostering positivity among flood-affected women. Conversely, formal support systems were found to hinder the pace of recovery. The primary goal of this research is to enhance the resilience of women and address mental health vulnerabilities in a male-dominated society. This study aims to contribute meaningfully to women’s literature while developing practical solutions and policies to address these issues across Pakistan.

In this paper, the inverse spectral problem method is used to integrate a Hirota type equation with additional terms in the class of periodic infinite-gap functions. The solvability of the Cauchy problem for an infinite system of Dubrovin differential equations in the class of six times continuously differentiable periodic infinite-gap functions is proved. It is also shown that the Cauchy problem is solvable at all times for sufficiently smooth initial conditions.

We investigate the use of shape sensitivity analysis based on topological derivatives to image a non-penetrable obstacle located inside a tubular acoustic waveguide. Assuming time-harmonic wave propagation, we reduce the problem to a finite section of pipe using the Dirichlet-to-Neumann map, and derive a closed form expression of the topological derivative for this situation. We investigate the method numerically on synthetic data. A particular feature of our study is the use of multi-frequency data.

This article provides information on the methods of mass measurement on the automatically controlled conveyor belt used in the sorting of potatoes, onions and fruits and vegetables from one zone to the next zone, and what parameters can be controlled by mass measurement. Using the methods presented in the article, when measuring the mass of potatoes, we will be able to control the angle of elevation of the hopper and the linear speed of the conveyor belt by processing the signals received through the strain gauges. In this way, we will be able to control the amount of mass passing through the weight measuring zone of potatoes moving on the belt together with the belt in a unit of time. Our automation of processes in the sorting area helps to reduce manual labor and to carry out the sorting process at a high quality level.

Studies of accretion disc luminosities and quasiperiodic oscillations around black holes may help us understand the gravitational properties of black hole spacetime. This work is devoted to studying the radiation properties of the accretion disk around the black holes in Kalb–Ramond gravity. We investigate the event horizon of the black hole spacetime and calculate the effective gravitational mass of the spacetime. Also, we analyze the circular motion of test particles in the black hole spacetime. The effects of the black hole charge and KR parameters on the particles’ effective mass, energy, and angular momentum at circular orbits and innermost stable circular orbits are studied. The frequency of Keplerian orbits and the radial and vertical oscillations of the particles along stable orbits are calculated and applied to analyze the existence of QPO in relativistic precession, warped disc, and epicyclic resonance models. QPO orbits’ locations with ratios of upper and lower frequencies of twin-peaked QPOs 3:2, 4:3, and 5:4 are analyzed compared to ISCO. We also obtain constrain values for the black hole mass, charge, KR field parameter, and QPO orbits found using Markovian chain Monte Carlo (MCMC) simulations for stellar mass (XTE J1550, GRS 1915+105), intermediate mass (M82-X1), and supermassive black holes (Sgr A*). Finally, we explore the radiative properties of the accretion disk around the charged black hole in KR gravity, such as the total radiation flux, accretion disc temperature, and differential luminosity.

One of the primary concerns associated with ion cyclotron resonance heating (ICRH) is the enhanced impurity sputtering resulting from radio frequency (RF) sheath formation near plasma-facing components (PFCs), such as limiters. Developing a sputtering model integrated with RF sheath simulations allows for a more comprehensive understanding of the kinetic behavior of incident ions and their interactions with the limiter surface. We accordingly develop an impurity sputtering model “PMSAD”, which computes the sputtering yield (amount of impurity) on the limiter surface based on incident ion characteristics and predicts the spatial distribution of impurities. The model provides a robust method for understanding and analyzing the impurity sputtering process from limiter surfaces, which is crucial for preventing ICRH surface erosion and reducing edge and core plasma contamination.

В данной работе метод обратной спектральной задачи применяется для интегрирования уравнения типа Хироты с младшими членами в классе периодических бесконечнозонных функций. Доказана разрешимость задачи Коши для бесконечной системы дифференциальных уравнений Дубровина в классе шесть раз непрерывно дифференцируемых периодических бесконечнозонных функций. Показано, что для достаточно гладких начальных условий решение задачи Коши существует при всех временах. Библиография: 67 наименований.