Tashkent Institute of Irrigation and Agricultural Mechanization Engineers, formerly Tashkent Institute of Irrigation and Melioration (TIIM) (Uzbek: Toshkent Irrigatsiya va Qishloq Xo'jaligini Mexanizatsiyalash Muhandislari Instituti (TIQXMMI)) or TIIAME is a university in Central Asia, which works for the development of the water industry, and supplies the country with professionals in this field. Tashkent Institute of Irrigation and Agricultural Mechanization Engineers is located in the Republic of Uzbekistan, Tashkent city, Kari Niyozov street, 39-house.
Рассмотрено повышение точности измерения влажности сыпучих материалов, имеющей критическое значение для обеспечения качества, сохранности продукции и эффективности технологических процессов в сельском хозяйстве, пищевой промышленности и строительстве. Дан краткий обзор методов измерения влажности и показано, что традиционные методы, включая гравиметрический анализ, хотя и отличаются высокой точностью, не обеспечивают оперативный и непрерывный контроль. Разработанметод измерения влажности с использованиемизмерительной системы, состоящей из сенсорной и интеллектуальной частей. Сенсорная часть – влагомер, содержащий ёмкостные датчики, регистрирует диэлектрическую проницаемость материала, сигналы датчиков поступают в блок сбора и предварительной обработки, где выполняется фильтрация и нормализация данных. Сенсорная часть обеспечивает стабильные измерения влажности пшеницы, кукурузы и песка в диапазоне 6–25 %. Интеллектуальная часть системы включает регрессионную модель, которая учитывает влияние диэлектрической проницаемости, объёмной плотности материала и температуры окружающей среды на точность измерений влажности и представляет собой многопараметрическую линейную модель, реализованную с помощью библиотеки scikit-learn (Python). Для оценки устойчивости модели применена десятикратная перекрёстная проверка. При экспериментальных исследованиях получены средняя абсолютная погрешность измерения влажности менее 1,8 % и коэффициент детерминации более 0,89, что подтверждает стабильность и воспроизводимость системы. Представленный подход демонстрирует, что интеграция ёмкостных сенсорных систем с интеллектуальными системами на основе регрессионных моделей позволяет повысить надёжность контроля и автоматизировать мониторинг влажности в производственных условиях. Разработанный метод измерения влажности и реализующую его систему можно адаптировать для различных сыпучих материалов и технологических сред.
This study presents a comparative analysis of three meshfree methods—Smoothed Particle Hydrodynamics (SPH), Element-Free Galerkin (EFG), and Smoothed Particle Galerkin (SPG)—for modelling orthogonal cutting of steel using the Johnson–Cook constitutive model within the LS-DYNA framework. The objective is to evaluate their accuracy, numerical stability, and physical consistency under identical boundary conditions. The simulations consider thermomechanical coupling, including plastic deformation and heat generation in the cutting zone. The results show that all three methods predict comparable cutting forces, with deviations within 8% of available literature data. However, significant differences are observed in numerical behaviour. The SPH method exhibits tensile instability and non-physical stress oscillations, while EFG and SPG produce smoother and more stable stress and temperature fields. Validation of the SPG method against three independent experimental and numerical sources demonstrates high accuracy, with an average error of 2.2% for the main cutting force. A parametric analysis indicates that increasing the strain rate from 0.0001 to 2 s⁻¹ increases the yield strength by a factor of 1.49. Furthermore, a strong correlation (r = 0.97) is observed between temperature and accumulated plastic strain. Owing to its inherent bond-based fracture mechanism and stable numerical performance, the SPG method is identified as the most suitable approach for industrial machining simulations.
Ultra-lightweight engineered cementitious composite (ULECC) is widely regarded as a highly promising material for manufacturing precast concrete slabs, owing to its low density, exceptional tensile ductility and crack width control capability. However, research has largely focused on the material-level high-temperature behavior of ECC, whereas its structural-level fire performance remains insufficiently understood. This study investigates the fire response and load-resisting mechanisms of precast ULECC composite slabs through ISO 834 standard fire tests and thermo-mechanical numerical simulations. The ULECC slabs demonstrated superior integrity and lower deformation rates in fire than conventional RC slabs. This improvement stems from ULECC’s higher tensile capacity, which provides enhanced flexural resistance, coupled with better thermal insulation that limits internal temperature rise. As a result, the peak temperature of the bottom reinforcement in ULECC slabs was reduced by over 34.5%, thereby alleviating fire-induced mechanical degradation. At the macro level, ULECC slabs demonstrated a significant reduction of 16.5%-19.8% in mid-span deflection. Numerical analyses further confirmed the enhanced fire resistance of ULECC slabs across different load ratios. Notably, the flexural resistance mechanism shifted from reinforcement-controlled to ULECC-layer-controlled, revealing a structural-level mechanism not observed in conventional RC slabs. This study provides a preliminary assessment of the fire performance of ULECC slabs based on limited experimental data, offering quantitative insights for the design of fire-resistant precast floor systems and highlighting an innovation at the structural level.
This article examines the functional state and physical performance indicators of adolescents aged 12–15 with visual impairment. The study assessed the functional capabilities and strength indicators of the respiratory, cardiovascular, and vestibular systems using vital lung capacity (VLC), heart rate (HR), the Ruffier–Dickson index, the Yarotsky test, and hand dynamometry. The results revealed that in adolescents with visual impairment, the functional capabilities of the cardiorespiratory system, physical performance, and certain coordination indicators are insufficiently developed. According to the Ruffier–Dickson index, satisfactory results were recorded in 12-year-old girls, while the indicators for the remaining groups were rated as below average. The slow recovery process after physical exertion and the results of the Yarotsky test indicate the need to improve the functional preparedness of this cohort through an individualized approach. The findings substantiate the importance of considering the functional state when organizing adaptive sports and physical education classes for adolescents with visual impairment.
The torque–tension behavior of engine cylinder head bolted joint systems in internal combustion engines is critical for ensuring reliable preload and structural integrity in automotive engine assemblies. This study investigates mismatched threaded cylinder head stud assemblies exclusively used in engine fastening systems. Experimental torque-controlled tightening tests were conducted to evaluate preload development in engine cylinder head bolted joint configurations. A finite element model of the engine cylinder head bolted joint system was developed specifically for threaded stud assemblies in internal combustion engines. The model simulates contact interaction, stress distribution, and axial load transfer within the engine fastening system. Validation against experimental data shows good agreement in torque–preload behavior. The results demonstrate that geometric mismatch significantly affects preload efficiency and joint reliability in engine cylinder head bolted joint systems.
