On measures for the efficient use of secondary resources and resource saving in a utility and construction complex

The present study is focused on the potential to reduce economic losses due to waste products generated in the utility and construction complex. The scientific research approach is based on the application of comparative, contrastive, quantitative and expert analysis methods. Domestic and foreign studies on the application of secondary resources in a closed economic cycle, as well as environmental safety require-ments at all stages of the secondary resource treatment, are analysed and systematised. The results of the authors’ own research in the field of assessment and analysis of the waste resource potential are presented. According to the obtained results, a low level of resource saving in the construction and utility sector is indi-cated due to the impossibility of characterising technological processes of these areas as non-waste or low-waste. A classification of secondary resources from the processed waste generated in the considered areas of economic activity is presented. The majority of waste materials from construction, repair, demolition and maintenance of immovable property isshown to be applicable for reuse in the production and economic cycle for both finished and semi-finished products. A set of organisational and technical measures, aimed at the reduction ofhazardous properties for such wastes and expansion of their further use in the form of secondary resources, is defined and substantiated. The organisational and technical measures presented in the study contribute to ensuring environmental protection from the negative impacts of industrial activity in the form of anthropogenic objects, such as construction and utility waste facilities, as well as to expanding the applica-tion of their resource potential.

Analysis of the current state of multi-storey residential areas in the city of Dushanbe

The aim is to identify the parameters of inter-highway micro-district areas having a significant impact on the quality of the urban environment. A classification of the inter-highway areas of existing multi-storey building systems in Dushanbe was proposed according to the following urban development indicators: absolute (micro-district area, building area, total area of the housing stock, area of all floors of buildings and structures, population); relative (population density, housing stock density); specific (land-to-building ratio, building development density factor). The classification covering 36 micro-districts of the central area of the Dushanbe agglomeration was developed using the method of hierarchical clustering implemented in the Statistical Package for the Social Sciences software. A dendrogram constructed using the method of intra-group connections showed that the existing development of Dushanbe features both problematic and problem-free inter-highway areas. Prob-lematic inter-highway areas are those micro-districts where the density of population and housing stock are overestimated in comparison with their values specified by the regulatory framework 1958–89 adopted across the entire USSR. Problem-free inter-highway areas are those micro-districts where the urban development indicators meet the regulatory requirements of both previous and mod-ern periods. The proposed classification of inter-highway areas in Dushanbe can be used as a con-ceptual and methodological basis for planning new housing construction in the sites under recon-struction and vacant sites.

Unrealised monumental sculpture as an architectural and artistic component of urban planning concepts on the example of the Bolshoy Moskvoretsky bridge

Built according to the designs of outstanding architects, bridges constructed in Moscow during the 1930s can be classified as philosophically-meaningful aesthetic structures having the ability to affect both contemporaries and their descendants. The object of the study consisted of the Bolshoy Moskvoretsky bridge, occupying a special urban development position among Moscow's architectural structures due to its location at the crossroads of the central historical and ideological core of the capi-tal. According to the General Plan of 1935, the Moskvoretsky bridge was intended as the most impor-tant of the four priority bridges. The main ideological message assigned to it was to lead to Red Square forming the ideological hub of world communism the cradle of the socialist world with the funerary mau-soleum of the ever-living leader at its centre. The study examines the design stages of the Moskvoretsky bridge during the pre-war period, as well as the creative confrontation in the post-war period between architect A.V. Shchusev and sculptor V.I. Mukhina that characterised the artistic image of the Moskvoretsky bridge. The study is aimed at the examination of incentive grounds for the emer-gence of a plastic solution and the reasons for the incompleteness of an outstanding work by A.V. Schusev. General scientific methods of research (analysis, synthesis), as well as a number of par-ticular scientific methods, such as system-structural, formal-logical, graphical virtual reconstruction, complex research and others, were used in the work. Additionally, an inclusion in scientific research of methodological approaches for studying the consequences of non-implementation of urban planning concepts and projects was performed. The results of the research are presented by the proprietary de-velopment of approaches to adequate methods of determining the potential impact of unimplemented major urban planning projects on the formation of the capital of Russia on the example of the Moskvoretsky bridge.

Validation of the load-bearing capacity of the frame assembly of metal structures on the standard 2.440 series using IDEA StatiCa

The paper aims to study the actual operation of a rigid frame unit for coupling a crossbar with a column on high-strength bolts according to the standard 2.440-2 series using modern software systems of the component finite element method. Special attention was paid to the operation of nodal elements, as well as their stress-strain state. Based on the results of static calculations, the cross-sections of the elements under consideration, as well as the components of the node (plates, bolts, seams, etc.) were selected from the tables of the standard series. Subsequently, using the component finite element method serving as the basis of the IDEA StatiСa software, all the components of the node were mod-elled with respect to acting forces. The conducted calculations confirmed the suitability of the obtained node model for identifying inconsistencies in the series and modern standards. Using stresses on plates, bolt and welding forces, as well as several forms of vibration to assess the stability of compo-nents, the applicability of the node in question in the proposed configuration was evaluated. It turned out that the node failed to meet modern standards in terms of design conditions. Moreover, the serial bolts were overloaded by almost 38%, and some welds approached the limit state. When used in real conditions, this can lead to serious losses, including human lives. Recommendations are given for changing the specific configuration of the node in order to protect it from the destruction of any nature, including local buckling failure.

Simulation model of a pulsed spiral hydro-mechanical energy converter in the heat supply system of a building

The objective was to develop a mathematical simulation model of a pulsed spiral hydro-mechanical flow energy converter with a variable speed operating in a pulsed mode. This simulation model can be used for calculating the optimal parameters of such devices. The mechanical energy generated by pulsed liquid can be applied in the driving gear of mini-hydroelectric generators working without drops in water pressure, pumping stations and heat networks providing pressure reduction, as well as in heater fans operating in damp or explosion-hazardous facilities. Pulsed spiral hydro-mechanical energy converters can be used for converting the energy of a liquid flow into rotational motion, which can be further transferred to an electric generator or capacitor. In this study, using the example of a hydro-mechanical converter with a cone-shaped coil, the equations of torque depending on the change in the frequency of flow interruption, the moment of inertia and the resistance in the supports were obtained. Design charts were built for the torque of a hydro-mechanical converter with a cone-shaped coil for a number of coil turns equal to 4 pcs., square tube section 0.00011 m2, and the length of the initial round 0.176 m. The validity of the equations was confirmed by a physical experiment with sufficient accuracy. The conducted comparison of simulated and experimental values showed their agreement with an error of less than 5%. According to the simulation results, design parameters for different models have their own characteristics.

Renewable energy sources: New opportunities for thermoelectric generators

The work sets out to analyse the application of new technologies in the design of thermoelectric systems, as well as to compare classical thermoelectric systems with those characterized by a spatial orientation of heat-transfer sides. New thermoelectric systems are increasingly competing with con-ventional methods of converting energy up to several hundred watts. In order to expand the application of thermoelectric systems, new design methods and solutions providing for a more efficient conversion of heat losses into useful energy should be developed. This work presents the results of a comparative analysis of a classical thermoelectric module and a thermoelectric module with a spatial orientation of the sides. It is shown that the efficiency of the latter is 36% and 43% higher than that of the former at currents of 4A and 8A, respectively. According to the findings, the efficiency of thermoelectric modules depends primarily on technical solutions in their design and engineering, rather than on the electro-physical characteristics of thermoelectric junctions. In order to increase the efficiency of thermoelectric systems, future work should be aimed at improving the design of thermoelectric modules. The applica-tion of new technologies in manufacturing thermoelectric modules allows the mutual influence of heated and cooled surfaces to be eliminated and the area of heat dissipation to be significantly expanded. The possibility of generating higher power values increases the efficiency of thermoelectric modules and expandsthe scope of their application, substituting conventional heat pumps.