Introduction: the article suggests a method for determining a thermal resistance of small and large-sized areas (one-dimensional and multidimensional problems) of wall enclosure. The subject of the study is the thermal resistance of homogeneous scalar medium (homogeneous wall enclosure). The aim is the determination of thermal resistance of a wall structure for areas of arbitrary dimension (by the coordinates xi, where 1 ≤ i ≤ d and d is the area dimension) filled with a scalar (homogeneous and isotropic) heat-conducting medium. Materials and methods: the article used the following physical laws: Fourier law (the value of the heat flow when transferring heat through thermal conductivity) and continuity condition for the heat flow rate leading to the thermal conductivity equation. Results: this method extends the standard definition of thermal resistance. The research proved that the active thermal resistance does not increase with increasing of the area dimension (for example, when switching from a thin shell or plate to a rectangle with length and width of the same order of magnitude). That is the sense of geometric inclusion, i.e., increase of the dimension of an area filled with a homogeneous isotropic medium. Evident expressions are obtained for the determination of active, reactive, and total thermal resistance. It is proved that the total resistance is higher than the active resistance since the reactive resistance is positive, and the wall possesses an ability to suppress the temperature fluctuations and accumulate/give up the heat. Conclusions: the appearance of an additional wall dimension (comparable length-to-thickness ratio) does not increase its active resistance. In the general case, the total thermal resistance exceeds the active thermal resistance no more than four times. Geometric inclusions must be considered in the calculation of wall enclosures that are variant from one-dimensional bodies.

A hydraulic structure is an object for the use of water resources, as well as for combating the harmful effects of water. Knowledge of the main parameters of the filtration flow is necessary for solving problems related to the design and operation of hydraulic structures. The article considers filtration calculations of a homogeneous closing dike, which is: determination of instantaneous filtration flow rate and seepage area. It is proved that when the length of the closing dike increases, the height of the seepage area monotonically decreases; the depression curve is constructed; critical time value after which the flow rate takes a constant value equal to the Dupuis flow rate is found.

The article analyzes the existing data on the use of organic additives in concrete in order to improve its thermal characteristics. The most promising types of additives for reinforcement have been identified, a series of experimental studies have been carried out and data on the strength and thermal characteristics of the obtained concretes have been obtained. Detailed conclusions and recommendations on the application of the obtained results are given.