Objectives. The development of a decompression semiconductor thermoelectric desalinator with ultraviolet radiation.

Methods. The design of a decompression semiconductor thermoelectric desalinator with ultraviolet radiation makes it possible to decrease the boiling points of seawater and the obtained fresh water and brine by changing the pressure in the desalinatior thus increasing the device’s energy efficiency.

Results. The use of the designed decompression semiconductor thermoelectric desalinator with ultraviolet radiation practically reduces the boiling point of seawater, completely eliminating Joule's parasitic heat release. The Peltier thermoelectric effect of heating and cooling is completely preserved, bringing the desalinator efficiency coefficient up to almost 100% and improving its energy-saving characteristics as a whole.

Conclusion. A decompression semiconductor thermoelectric desalinator with ultraviolet radiation can be used to produce fresh water and concentrated solutions from any aqueous solutions, as well as to treat wastewater from industrial enterprises with simultaneous bacterial and virus disinfection. The construction materials of the desalination device are environmentally friendly. 

Objectives.The aim of the article is to develop the design and carry out the physical and mathematical modelling of a device for producing fresh water from atmospheric air in coastal areas, as well as under the conditions of sea transport.

A Method for constructing the device for producing fresh water from atmospheric air is developed on the basis of a physical and mathematical model. Fresh water is obtained by condensation on a cold surface, which dew point is created using the natural cold of seawater with the application of the energy of moving waves for its circulation. The heating of the surface air layer adjacent to the cold surface by solar concentrators intensifies the process of the moisture condensation.

Results. Data is obtained on the quantity (mass) of fresh water produced per unit of condensation surface area (1 m2 ) for 1 hour depending on the temperature difference between the condensation surface and seawater. The influence of the characteristics of solar concentrator and liquid heat remover with seawater on the device parameters is studied.

Conclusion. It is established that the amount of the fresh water obtained from atmospheric air strongly depends on the temperature difference between the condensation surface and seawater. Thus, according to calculations, with an increase of the latter by 45 K, the mass of fresh water obtained from a condensation surface of 1 m2 in 1 hour approximately doubles to 5.8 kg. 

Objectives.The aim of the study is to develop a cyclic absorption refrigerator unit that implements technology for producing cold from solar radiation energy. Its distinctive feature comprises a highly developed solar receiving unit, consisting of two parallel-connected absorber generators whose reactors are installed in individual heat-insulated “hot box” cabinets.

Method. The geometric characteristics of the absorber generator are based on the calculations of the optical and heat energy efficiency of the device models.

Results. The physicochemical characteristics of activated carbons (AC) of various production are studied. The absorption capacity of the following working pairs is determined: AC-ammonia, AC-methylamine, AC-ethylamine. The calculated coefficients for the Dubinin-Radushkevich structural equations are obtained. An experimental solar energy refrigerator unit is tested using a working pair of AC-ammonia in an open test area. The operability of the upgraded device is proven. Exergetic coefficient dependencies are determined according to the developed software algorithm based on a simplified thermodynamic cycle. The areas of possible application and use of solar power refrigerator units with the studied working pairs are determined.

Conclusion. The increased unit efficiency consists in the optimal layout of all elements of the absorber generator, including the reactor, two flat mirror concentrators, a thermal substrate, a reduced internal air space volume, a double-glazed window made of two sheets of glass and a calculated thickness of heat-insulating Ripor foamed polyurethane. 

Objectives. The aim of this work is to modernise a VT-KHTI densimeter operated by the method of hydrostatic weighing in order to study the density of highly viscous oils and oil products in the temperature range from 293 K to 473 K at atmospheric pressure.

Method. Among the many methods for studying density, the following were used in the course of the study: the constant- and variable-volume piezometer method and the method of hydrostatic weighing.

Results. The results of the densimetric study of highly viscous oils obtained from the Republic of Tatarstan in the temperature range from 293 K to 473 K at atmospheric pressure. The following grades are presented: Ashalchinskaya oil (super-viscous, SVO); Kuakbash oil (sulphur), Kichuy oil and Devon oil. Following an analysis and selection of methods for measuring density, a technique for error estimation and densimeter calibration is presented. A calculated expression for the hydrostatic weighing method, derived from the modernised hydrostatic densimeter design for measuring the density of highly viscous oils, is presented.

Conclusion. The VT-KHTI densimeter for vacuum working fluids has been modernised and calibrated for research work on measuring the dynamic viscosity coefficient of both Newtonian and non-Newtonian liquids. 

Objectives. The article discusses a thermoelectric cooling system (TECS) for ensuring the thermal regime of modular electronic equipment (MEE) located in a cabinet. The main task of the experimental studies is to determine the temperature dependencies of the air-cooled heat-generating elements of a printed circuit board simulator according to TEСS parameters.

Method. In order to conduct experimental studies of a thermoelectric cooling system for printed circuit boards in cassette units using a thermoelectric cooling system, a prototype designed and manufactured in the laboratory was studied on a testing stand.

Result. The directions of constructive solutions for using a TECS device are presented along with a description of the testing stand and procedure. The dependencies of the temperature of the printed circuit board simulator on the heat power taken away by the TECS are considered along with the temperatures of hot and cold junctions, the air flow velocity and the distance between the electronic boards.

Conclusion. The operability of the developed MEE cooling system is confirmed by the experimental studies; the specified cooling method has advantages over conventional forced or natural method and can achieve the temperatures required by the technical operating conditions; when choosing a fan to provide forced circulation of the air flow in the system, it is necessary to take into account the speed of the air flow in the channel; it is necessary to reserve the power of the power supply for the TECS operation in proportion to the power of the heat sources. An important additional point for the functioning of the thermoelectric cooling device is the necessity of ensuring the effective removal of heat from the hot junctions of the thermoelectric module without which it is impossible to use the proposed system. 

Objectives. The aim of the work is to develop a situational decision-making model that provides effective management of the activities of large construction engineering organisations under the unstable conditions of the economic environment.

Method. The research methods are based on the application of the methodological foundations of situational management and the principles of processing expert data using the mathematical apparatus of fuzzy sets.

Results. A method for managing the activities of a construction engineering organisation under an unstable economic environment is proposed. Logical-transformational rules for deriving an information-analytical model of situational management and decision support under conditions of uncertainty are developed. The necessary conditions for the effective use of various logical-transformational inference rules and the need for an organisational management transition to multi-step situational management of the construction engineering organisation are defined.

Conclusion. The results of the study allow the effective management of various types of activities of a large construction engineering organisation to be carried out in an unstable economic environment (i.e. under the unstable conditions of the contemporary market). 

Objectives. The aim of the study is to develop a model of a predictive maintenance system allowing the output parameters of a high-capacity distillation unit to be stabilised.

Method. The problem of controlling the collection of oil products of a given fractional composition can be reduced to the task of controlling the temperature regime at draw-off trays. In this case, temperature control tasks are considered as control actions. In order to implement the proposed control principle, a mathematical model was constructed allowing the oil fraction content to be converted to directly controlled temperatures.

Results. Based on the analysis of the technological process and design features of the atmospheric distillation column, the vectors of maintaining and disturbing actions are determined along with the optimisation criterion for the maintenance problem. In order to improve the dynamic characteristics of the control object, oil product quality parameters are introduced into the predictive maintenance model along with the supplementation of existing control loops with intermediate parameters.

Conclusion. An analysis of the structural features of the atmospheric pipe still and the existing approach to the distillation column maintenance reveals certain disadvantages associated with the lack of operational quality control of the collected oil products, as well as the need to expand the list of stabilised technological parameters in order to optimise the technological process. It is shown that in order to switch to the proposed maintenance approach, it is necessary to develop a static model reflecting the dependency of the potential yield of the required fractions on the raw material composition along with a dynamic model in the form of a multi-parameter optimisation problem. 

Objectives. “Burst errors” representing groups of accidentally or intentionally distorted or “erased” characters in blocks of information arrays violate the integrity of their content. However, the use of special codes for detecting and correcting such errors significantly reduces the speed of information transfer due to the need to introduce redundancy in the form of a large number of control characters. Therefore, this study sets out to develop a method for correcting burst errors.

Method. A possible approach for correcting burst errors consists in interleaving preliminary permutations of information array elements between different array blocks. After eliminating the results of element permutations, these procedures cause the interleaving of distorted elements occurring during the transfer or storage of the information array between its various blocks, causing single or minor fold errors.

Result. For solving problems of this class, a new method of permuting elements of an nxnset of finite sets is proposed based on the index structuring of the formed configurations. These sets are interpreted as information arrays of the same configuration, and the permutation – interleaving – of their elements is carried out according to the method of configuration formed by the index structuring of their location.

Conclusion. Three methods for interleaving elements of the original information in arrays are proposed: between rows, between columns and combined – between rows and columns. The proposed interleaving methods based on the preliminary conversion of information arrays by permuting elements according to given algorithms allow their distortions under the influence of burst errors to be corrected. Thus, the task of combating the burst errors leading to the destruction of individual groups of characters can be reduced to solving a simpler problem of minor fold error correction. 

Objectives. The aim is to study the dependency of the distribution of integral heat transfer during turbulent convective heat transfer in a pipe with a sequence of periodic protrusions of semicircular geometry on the Prandtl number using the calculation method based on a numerical solution of the system of Reynolds equations closed using the Menter’s shear stress transport model and the energy equation on different-sized intersecting structured grids.

Method. A calculation was carried out on the basis of a theoretical method based on the solution of the Reynolds equations by factored finite-volume method closed with the help of the Menter shear stress transport model, as well as the energy equation on different-scaled intersecting structured grids (fast composite mesh method (FCOM)).

Results. The calculations performed in the work showed that with an increase in the Prandtl number at small Reynolds numbers, there is an initial noticeable increase in the relative heat transfer. With additional increase in the Prandtl number, the relative heat transfer changes less: for small steps, it increases; for median steps it is almost stabilised, while for large steps it declines insignificantly. At large Reynolds numbers, the relative heat transfer decreases with an increase in the Prandtl number followed by its further stabilisation.

Conclusion. The study analyses the calculated dependencies of the relative heat transfer on the Pr Prandtl number for various values of the relative h/D height of the turbulator, the relative t/D pitch between the turbulators and for various values of the Re Reynolds number. Qualitative and quantitative changes in calculated parameters are described all other things being equal. The analytical substantiation of the obtained calculation laws is that the height of the turbuliser is less for small Reynolds numbers, while for large Reynolds numbers, it is less than the height of the wall layer. Consequently, only the core of the flow is turbulised, which results in an increase in hydroresistance and a decrease in heat transfer. In the work on the basis of limited calculation material, a tangible decrease in the level of heat transfer intensification for small Prandtl numbers is theoretically confirmed. The obtained results of intensified heat transfer in the region of low Prandtl numbers substantiate the promising development of research in this direction. The theoretical data obtained in the work have determined the laws of relative heat transfer across a wide range of Prandtl numbers, including in those areas where experimental material does not currently exist. 

Objectives. The development of a mathematical model for the increased turbidity zones of the Aksay river in order to determine the siltation volumes of the Aksay water reservoir storage.

Method. The mathematical model is developed using the theory of probability and the theory of random process outliers. The model takes the normal distribution of the horizontal and vertical components of the instantaneous flow velocities into account, as well as the Rayleigh law of the distribution of their maxima. The proposed model is used to calculate the “turbidity tail” of the Aksay river.

Result. Due to the multifactorial nature of the continuously associated processes of siltation and deposition of suspended and bottom sediments in the upper pounds of the Aksay reservoir storage hydrological system, a mathematical model of the reservoir accretion process is developed. This model provides the reliability of accretion forecasting with spatial and temporal correlation with the siltation process model, which is actually feasible on the basis of computer simulation.

Conclusion. The developed model, which is based on a probabilistic approach and the theory of random process outliers, reflects the overall process of sediment transport in open channels. The development and execution of simulation programmes is carried out using the Microsoft Developer Studio (MDS) and the Fortran Power Station algorithmic language, which comprises not only a programming system, but also a set of tools for supporting large software projects integrated into MDS. 

Objectives. This article presents an application for the processing of scanned images of sales receipts for subsequent extraction of text information using the Tesseract OCR Engine. Such an application is useful for maintaining a family budget or for accounting in small companies. The main problem of receipt recognition is the low quality of ink and printing paper, which results in creasing and tears, as well as the rapid fading of printed characters.

Methods. The study is based on a number of algorithms based on mathematical morphology methods for opening, closing and morphological gradient operations, as well as image conversion, which can significantly improve the final recognition of characters by Tesseract.

Results. In order to solve this problem, a special image normalisation algorithm is proposed, which includes locating a receipt on an image, processing the received image section, removing image capture and carrier defects, as well as point processing for restoring missing characters. The developed application supports increased recognition accuracy of text information when using Tesseract OCR.

Conclusion. The developed system recognises characters with fairly high accuracy, demonstrates a result that is better than that obtained when using the unmodified Tesseract method, but which is still inferior to the recognition accuracy of ABBY FineReader. Methods are also been proposed aimed at improving the developed algorithm. 

Objectives. In order to determine the security of a special-purpose informatisation object, it is necessary to calculate the effectiveness indicators of information security (IS) measures aimed at preventing unauthorised access (UA) threats associated with information leakage through technical (acoustic) channels. In order to determine the actual channels of information leakage, it is necessary to develop a list of actions to neutralise potential threats, including the development of an information protection system for a special-purpose informatisation object.

Method. A security assessment of the special-purpose informatisation object is carried out using expert documentary and instrumental methods.

Results. The results of evaluating the indicators of protection against information leakage through the air (acoustic) channel are presented and aspects of improving special measures for protecting information at the special-purpose informatisation object are identified.

Conclusion. Due to its relevance, the direction of this study requires further development of organisational and technical measures to implement the requirements of regulatory documents on the protection of information in special-purpose informatisation objects. 

Objectives. To study the dependencies obtained when determining the coordinates of an earthquake hypocentre using the figures of fourth and second orders.

Method. A comparative analysis of determining the coordinates of the earthquake focus using the Cassini oval method, both taking errors in the readings of seismic sensors into account the and ignoring them, is presented.

Result. A new method is proposed for determining the coordinates of the earthquake hypocentre, which uses the fourth-order figure, the Cassini oval, in the calculations. A graph is obtained for the distribution of errors in determining the coordinates of the earthquake focus (using the Cassini oval) depending on the relative position of two seismic sensors with different values of their errors in determining the difference in travel times of seismic waves.

Conclusion. Since the calculation results are independent of the error sign in determining the difference in the arrival times of seismic waves, the method is suitable for the initial determination of the coordinates of the earthquake hypocentre as well as for comparison with the results of other methods for identifying the error sign. 

Objectives. In order to determine a residual safety factor, a finite element method is considered for determining the bearing capacity of reinforced concrete plates having defects in the form of cracks.

Method. The methodology is based on the use of structural calculation algorithms that take physical nonlinearity implemented in the PRINS programme into account. These algorithms assume the use of the same computational scheme in the process of solving the problem. However, the specificity of the task consists in considering differences between the calculation schemes of the initial structure and the structure having cracks.

Result. With this in mind, the algorithms of nonlinear structural analysis according to the PRINS programme are supplemented with an option that allows the parameters of the design scheme to be changed in an end-to-end calculation process. Multilayer finite elements are used to study the load-bearing capacity of reinforced concrete plates, each having a specific material package. The modernisation of the design scheme in this case consists in replacing one package of materials with another. The input file of the PRINS programme is supplemented by a description of cracks with an indication of their location and all other relevant characteristics. Examples of problems arising when determining the bearing capacity of a plate with defects in the form of cracks under various boundary conditions are given.

Conclusion. The problem of determining the bearing capacity of reinforced concrete plates with defects in the form of cracks can be effectively solved using a reconfigurable design scheme for end-to-end calculation. In the event of defects appearing in the form of cracks, this will enable operational services to monitor changes in the bearing capacity of buildings and structures containing reinforced concrete plates, as well as to determine the operability of structures and make substantiated decisions in case of repair. 

Objectives. This study was aimed at determining the actual flow rate of a gaseous working fluid by the pressure drop in the constriction device with its changing parameters (speed, pressure, temperature, gas composition).

Method. Since the pycnometric method provides high accuracy in determining the density and is simpler than the calorimetric method for determining the calorific value, the value of the latter can be checked using the dependence proposed in the article. In the event of a discrepancy between the calculated value of the calorific value and the experimentally obtained value of more than 0.5%, the determination of the calorific value and the density should be repeated. The relationship between the density and calorific value of a gas is subject to verification and refinement when gas from other fields is used. In all cases, a sampler should be used to accumulate an average gas sample over an appropriate period of time. The methodological error in calculating the amount of gaseous working fluid can be eliminated or reduced by using a computer as part of an automated heat supply enterprise management system.

Results. It was established that the calorific value of energy fuels non-linearly depends on the hydrogen and carbon contained therein; a formula has been developed to describe this relationship. When studying the energy characteristics of fuels, a previously unknown regularity was established: hydrocarbons ethylene, benzene and annelated hydrocarbons (naphthalene, anthracene, naphthacene, etc.) form the homologous series C_nH_(n+6)/2  with the homological difference C₄H₂, while all other series of hydrocarbons have a homological difference CH₂.

Conclusion. The greatest difficulties consist in accounting (measuring) the amount of energy contained in the fuel used at TPPs, mainly natural gas, and the coolant, since there are no appropriate technical means for direct measuring the amount of a particular type of energy. The developed theoretical provisions make a certain contribution to the development of the scientific foundations of heat and gas supply, increase accuracy and reduce the complexity of calculating the technical and economic indicators of thermal power plants and boiler houses. 

Objectives. The aim of the work is to demonstrate the fundamental difference between fibre-reinforced foam concrete and traditionally-used wall materials in terms of tensile strength.

Method. An analysis of the effectiveness of heat-insulating and structural fibre-reinforced concrete in terms of their mechanical and physical properties, including frost resistance, is carried out.

Results. The characteristics of the most important operational properties of fibre-reinforced foam concrete for insulating and structural purposes are given. The possibility of expanding the range of prefabricated products in connection with the level of tensile strength of fibre-reinforced foam concrete under bending is substantiated. Empirical data concerning the practical use of original products from fibrereinforced foam concrete in the construction of residential and public buildings in Rostov-on-Don is presented.

Conclusion. It is shown that, in order to increase the heat transfer resistance of building envelopes, the use of fibre-reinforced foam concrete in the rehabilitation of existing buildings can ensure their high fire safety subject to the required sanitary and hygienic conditions. Fibre-reinforced foam concrete, being a gas-filled concrete of non-autoclave hardening, allows new design solutions to be offered for heat-insulating and structural purposes in the construction complex of the Russian Federation, which practical application expands the range of factory-made products, reduces energy consumption and contributes to the diversity of the architectural appearance of buildings. 

Objectives. The need to ensure the reliable functioning of expensive airfield structures poses great challenges for surveyors, designers, builders and operators of these structures. These tasks are complicated by the continuous development of aircraft, an increase in the intensity of their movement, an increase in mass, take-off and landing characteristics of aircraft and the degree of operational impact of aircraft on airfield structures. The aim of the study is the technological solution model proposed by the authors for the carrier layer of artificial runway pavement in the form of a honeycomb structure of closed steel sheets filled with concrete along with a method for assessing the strength and determining the rigidity of its aggregate.

Method. A method is proposed for assessing the ultimate strength and determining the real stiffness parameters of structural layers of a runway with a constructive solution to the question of concrete work in cramped conditions (“cage effect”) from the impact of manifold repeated operational aircraft loads. This method is based on the fundamental principles of the deformation theory of reinforced concrete, developed by V.M. Bondarenko and elaborated in relation to the volumetric stress state of reinforced concrete structures in the works by G.A. Geniev, K.L. Surov and V.I. Rimshin.

Result. An analytical dependency is obtained for establishing a discrete value, a generalised (integral) parameter of the material deformation of the carrier layer, i.e. the equation of the mechanical state of steel-reinforced concrete in a complex stress state, as well as the repeated application of an operational aircraft load at an arbitrary stress point of the artificial runway pavement taking into account the influence of changes in strength, reinforcement, temperature, humidity and rheological factors.

Conclusion. The introduction of new technological principles for reinforcing and concrete laying into the design solutions of the bearing layers of artificial runway pavement allows their bearing capacity and rigidity to be significantly increased due to the redistribution of impact energy and the efficient use of the properties of structural materials during loading. 

Objectives. The aim of this study was to identify variation patterns of the in-series variation coefficient of adhesive strength to base and the dependency of the frost resistance coefficient on the criterion of adhesion on prescription factors of fine-grained concrete obtained from dry building mixtures based on various Portland cements containing various low-modulus inclusions and redispersible polymer powders from 0 to 3%. According to GOST 31357, the main quality indicators of the hardened mixture or fine-grained concrete, in addition to frost resistance, include the indicator of “frost resistance of the contact zone”, which characterises the ability of the hardened concrete to maintain adhesion to the base during normal separation following a certain number of freeze-thaw cycles.

Method. The tests of the main samples were carried out after 75 freeze-thaw cycles in accordance with GOST 31356. The marks of the frost resistance of the contact zone are set from FKZ25 to FKZ100. The number of freeze-thaw cycles is taken as a mark, after which the adhesion strength to the base, determined according to GOST 31356, is at least 80% of the strength of the control samples. The arithmetical average is taken at between at least 5 values, while the variation coefficient measured across a series of adhesion strength values is not considered.

Results. The average values of the variation coefficient of adhesion strength were: following 75 cycles of freezing-thawing – 0.224 (in a range from 0.058 to 0.616); following 25 cycles of freezing-thawing – an average of 0.129 (in a range from 0.016 to 0.352). The variation coefficient of adhesion strength can exceed the variation coefficient of compression strength by approximately 2.5 to 3 times. When introducing the redispersible powders into the structure of fine-grained concrete, there is no unambiguous pattern of change in the values of the variation coefficient of adhesion to base and it is possible to increase or decrease this value, while the values of the variation coefficient of adhesion can vary by an order of magnitude.

Conclusion. For all concretes, there is a tendency of increase of the coefficient of frost resistance with a decrease in the adhesion variation coefficient both after hardening under normal conditions as well as during cyclic freezing and thawing. When conditions VF/V28A<1 are met, the coefficient of frost resistance of adhesion, determined when considering the variation coefficient, will satisfy the requirements of GOST 31356. 

Objectives. The study was aimed at improving the reliability of heat supply systems. At present, this is one of the most relevant topics in the field of heat supply. The issue of reliability of heat supply is of great importance in terms of the safety of citizens and the state as a whole. Due to the severity of winter conditions and risk of hypothermia, heat supply security can be considered to be as critical as food security. Therefore, the reliability of heat supply systems becomes one of the most important aspects of the security of the state.

Method. The study was carried out using the method of reservation of the heat supply system by looping.

Result. In order to avoid the defrosting of the heat supply system and reduce additional costs, a redundancy scheme was proposed with one-way connection to the looped main pipelines, additionally looping the pipelines of the heat supply systems between two boiler rooms. The calculation of losses in the event of an emergency in the heating system was carried out.

Conclusion. The most important problem requiring immediate solution is how to increase the reliability and redundancy of the heat supply system itself, in order to achieve minimal discomfort for consumers of heat energy at the time of failure of the source or transmission of the heat supply system. The proposed method for increasing the reliability of operation of heat supply systems is characterized by a high efficiency, since allows the number of idle hours and the total amount of short-received heat to be reduced.