Academy of Sciences of the Republic of Tajikistan

The specific heat capacity, heat-transfer coefficient and thermodynamic functions of the AlV0.1 aluminum conductor alloy with sodium were determined in the cooling mode using the known specific heat capacity of a reference aluminum sample (grade A5N). To this end, polynomial fits describing the cooling rates were obtained by processing the cooling-rate curves of the AlV0.1 alloy samples with sodium and of the reference. Using the cooling-rate values of the tested alloy samples and of the reference, together with their masses, the specific heat capacity and thermodynamic functions of the AlV0.1 aluminum conductor alloy with sodium were calculated as functions of temperature. It was shown that with increasing temperature and sodium content the heat capacity, enthalpy and entropy of the AlV0.1 aluminum alloy increase slightly, while the Gibbs free energy decreases.

Для достаточно больших целых чисел $K$, $x$, $y$, $q$, где $K\le y

Computational Fluid Dynamics (CFD) is a modern numerical analysis technology based on computer numerical simulation models for simulating and analyzing fluid flow, heat and mass transfer, and related physical phenomena. It predicts intricate fluid flow patterns by numerically discretizing and solving the governing equations for describing the conservation mechanics of mass, momentum, and energy in fluid. CFD is instrumental in elucidating the mechanisms underlying complex fluid dynamics and material transport within agricultural settings. This paper systematically reviews the latest research progress of CFD in the design and engineering applications of agricultural machinery. It elaborates on the technical principles, governing equations, and typical computational models of CFD, following by the traditional simulation workflow. The review highlights the practical applications of CFD and the integrated CFD-DEM approach in critical agricultural operations of seeding, conveying, cleaning, spraying, fertilizing, harvesting, drying, and greenhouse climate management. The effectiveness has also been examined in enhancing equipment design, boosting operational efficiency, and minimizing energy use and crop damage. In addition, CFD’s role is summarized for advancing agricultural machinery towards greater efficiency, precision, and intelligence. It critically addresses the existing challenges, for examples the intricacies of multi-physics coupling, scarcity of validation data, and constraints on computational resources. The future development trends are prospected by combining CFD with artificial intelligence and high-performance computing (HPC), aiming to provide a systematic theoretical reference and technical path for digital design and innovation in agricultural engineering.

The effect of gallium, indium, and thallium added in the rangie from 0.05 to 1.0 wt

Specific activity of radioactive isotopes 40K and 137Cs from the uranium and thorium series is analyzed in samples of aerosol particles and soil in Northern Tajikistan compared to data obtained in the Southern and Central Tajikistan. This investigation allows the temporal variability of radioactive isotopes to be conceived and contributes to a solution of problems of regional radioactive loading within the impact zones of powerful dust storms forming in the region known as the Afghan wind. A comparative analysis of isotope concentrations in atmospheric aerosols and soils in the Northern regions of the country revealed that the levels of certain isotopes in aerosol particles are higher than their concentrations in soils of Northern Tajikistan. It has been demonstrated that fine-dispersed aerosol particles constitute one of the pathways for radionuclide dispersion.