International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

This article provides a systemic analysis of the application of analytical methods for solving differential equations of heat and mass transfer for the design of building envelopes in the context of modern energy efficiency requirements and the digitalization of the construction industry. It is demonstrated that analytical solutions remain critical for the design of multilayer walls and roofs, thermal stability and vapor permeability calculations, and the verification of BIM models and smart home systems. A review of classic and new analytical results from 2015–2025 is presented, including the use of physically-informed neural networks (PINN) for real-time thermal protection optimization. Examples of implementation in regulatory documents, software, and microclimate management systems are provided.

This paper investigates the effects of oil quenching and tempering at various temperatures on the mechanical and thermal properties of X155CrVMo12-1 tool steel. The steel specimens were austenitized at 1030 °C for half an hour, followed by quenching in oil and tempering at temperatures ranging from 50 °C to 700 °C. Mechanical properties were assessed by measuring the microhardness of the samples after each heat treatment. Thermal properties were investigated using the Xenon flash method (DXF analysis) to measure thermal diffusivity, thermal conductivity, and specific heat. The results show that the highest microhardness values were achieved after quenching,
while the lowest values were observed for thermal diffusivity and thermal conductivity. Following quenching, the microhardness values gradually decreased with an increase in tempering temperature, whereas the values of thermal diffusivity and thermal conductivity increased. Even after tempering at 500 °C, the microhardness values remained quite high, with only a 23.41% decrease from the quenched state. Furthermore, there was a significant improvement in thermal properties, with thermal diffusivity increasing by 38.34% and thermal conductivity improving by 23.99%.

In this paper, analytical expressions are obtained for determining the temperature distribution in a two-layer medium with local heating concentrated on the interface surface of the layers for a stable and linearly variable relative to the temperature of the thermal conductivity coefficient of the materials of the layers. Numerical calculations are given, and on this basis, the curves of temperature distribution as a function of spatial coordinates were constructed, which make it possible to
analyze the temperature regimes in a two-layer plate.

The article presents a study of the sound and thermal insulation properties of ceramic plates with cavities, designed for beehives. The plates are obtained by the “casting” method from a water-dispersed colloidal system based on a patent-protected quartz glass-ceramic. They are composed of amorphous SiO2, mullite and cristobalite. To measure the thermal conductivity, a thermal chamber is constructed with a heater installed in it. Given that the heat flow passing through the three-layer ceramic plate for beehives is constant, the temperature difference between the two opposite sides of the plate at steady state (at constant heat flow) is measured and the thermal conductivity is calculated. A two-chamber method is used to determine the sound insulation capacity of the ceramic plates for beehives. The sound pressure of the sound waves – the incident one and of the wave which has passed through the sample –is measured in the frequency range from 100 to 3150 Hz