Science and Transport Progress

7-14

Authors: V. A. Kozachyna

Purpose.Sedimentation by gravity is the most common and extensively applied treatment process for the removal of solids from water and wastewater and it has been used for over one hundred years. Sedimentation tanks are one of the major parts of a treatment plant especially in purification of turbid flows. Horizontal settlers are mainly used for purification of high quantity of water. In these tanks, the low speed turbid water will flow through the length of the tank and suspended particle have enough time to settle. Finding new and useful methods for calculating and increasing hydraulic efficiency of horizontal settlers is the objective of many theoretical, experimental and numerical studies.But currently used models and methods in Ukraine do not allow taking into account geometrical form and various design features. In this paper the numerical model was developed to evaluate the effectiveness of horizontal settler with modified structure. Methodology. Numerical model is based on: 1) equation of viscous fluid dynamics; 2) mass transfer equation. For numerical simulation the finite difference schemes are used. The numerical calculation is carried out on a rectangular grid. For the formation of the computational domain markers are used. Findings.The model allows obtaining the purification process in the settler with different form and different configuration of baffles. Originality. A new approach to investigate the mass transfer process in horizontal settler was proposed. This approach is based on the developed CFD model. The fluid dynamics model was used for the numerical investigation of flows and waste waters purification. To investigate influence of baffles on settler efficiency physical experiment was carried out. Practical value.The developed model has more capacity than the existing models in Ukraine. The developed model allows computing quickly the efficiency of water purification in settlers. The model is not computationally expensive. Calculation time of one variant of the problem takes few minutes.

24-36

Authors: M. M. Kolos, M. A. Gonchar

Purpose. The scientific paper highlights improving the technology of railway transport in the Republic of Belarus in conditions of electronic legally significant documents. Methodology. The study covered the collection of statistical data on the duration of separate technological operations performance, the evaluation of static data and the descriptive analysis of their characteristics. When assessing the effectiveness of the proposed measures we used methods of expert estimations, methods of evaluating the effectiveness of IT investments. Findings. Technology, hardware, software, organizational and other aspects of electronic legally significant documents used in freight and commercial work are determined. The work defines the most important directions of technology improvements at Belarusian Railway entities and their relations with shippers and consignees through the use of electronic legally significant documents. These directions are as follows: simplification of station commercial costs accounting, automation of technological operations, improving the interaction between the railway tracks and adjunction stations, simplification of transport planning and demand performance record, implementation of common information space for all participants of transportation process. The predictive estimate of efficiency for implementation of electronic legally significant documents in freight and commercial work of the Belarusian railway is calculated. Originality. This article presents a dual model of digital signature as a tool for the automatic fixation of technological operations or for specifying the time for its implementation, which allows converting a number of technological processes to a new level, helping to create a common information space of freight traffic. Practical value. The obtained results are used to form the list of the actions directed on perfection of railway transport technology in conditions of electronic legally significant documents, assessment of their significance and phasing of their implementation on Belarusian railway. The results of the project will allow: to reduce costs of shippers, consignees, railroads, to improve productivity, cost competitiveness of railway transportation and quality services, to create common information space and, as a consequence, to improve the quality of work with information flows and access to information for all participants of transportation process.

47-54

Authors: O. A. Nazarov

Purpose. Clear and uninterrupted operation of humps depends on the quality of technical equipment and control technology of cuts speed. Technology of interval and purposive regulation of cuts speed is used at most humps. The article discusses ways to reduce the cuts rolling speed to a safe level at the beginning of the sorting sidings equipped with quasi-continuous speed control system. Methodology. It proposed three fundamentally different ways to reduce the cuts rolling speed at the beginning of the sorting siding. The analysis of the ways to reduce cuts rolling speed to a safe level at the beginning of the sorting sidings was conducted using simulation the process of cuts rolling from humps equipped with quasi-continuous speed control. Findings. As a result of analysis, the inappropriateness of opposite elevation using on the roll-out part of the hump after the last separation switch point. Spot regulators of cars speed can be used to reduce the cuts rolling speed at the beginning of the sorting siding, but this leads to a division conditions deterioration on the last separating switch points of long cuts with the following after them short cuts. Reducing the cuts rolling speed at the beginning of the sorting siding can be carried out using the beam on a stationary wagon retarders park brake position. Control Algorithm park brake position is quite simple. All produce should be unhooked from it at a safe speed. If the accuracy of the implementation of the set speed output to unhook from the park brake position is low, it is possible to eliminate the error of point regulators cars speed. Originality. The question where to start location point of wagon retarders zone to reduce speed to cut level requires additional research. Reducing rolling cut the speed at the beginning of the sorting sidings can be carried out using the beam on a stationary wagon retarders park brake position. Practical value. Control Algorithm park brake position is quite simple. All produce should be cut from it at a safe speed. If the accuracy of the implementation of the set speed output to cut from the park brake position is low, it is possible to eliminate the error of point regulators cars speed.

63-70

Authors: V. V. Kovalenko

Purpose. The study aims to identify the causes of premature destruction of concrete sleepers of one of Ukrainian producers. Methodology. Applied microstructural, fractographic, X-ray microanalysis revealed causes of transient corrosion processes in concrete. Findings. Subject of study in this work is a cement rock and concrete structure of prematurely shattered concrete sleepers. Another premature destruction of concrete sleepers was studied using the traditional method for Dnipropetrovsk National University of Railway Transport named after Academician V. Lazaryan (DNURT) that was patented in 2009. The conducted research showed: 1) a cement rock near the sand particles of high concentration of chlorine and alkali metals exceeding permissible in existing standards; 2) different grained cement crystals indicates excess of water in the concrete mixture; 3) the presence in the cement rock structure of wood fibers, which are due to the additional moisture absorption accelerate chemical reactions in the operated concrete sleepers; 4) speed of alkaline-silicic-acidic reaction in concrete sleepers is 5 microns per year; 5) availability of wood fibers indicates unsatisfactory purity of aggregates screening, including crushed stone; 6) chlorine ions further accelerate structural transformation reaction of cement. Originality. The paper found the rate of corrosion processes in concrete sleepers of Ukrainian producer. The influence on the corrosion rate of contamination of large aggregates of organic substances, including wood fibers was shown in the article. There were presented characteristic signs of accelerating corrosion processes as a result of excess of water and chlorine ions in the structure of cement rock. Practical value. Identifying the typical signs of premature destruction of concrete under rail foundations prevents massive failure of railway sleepers, which affects negatively the railway traffic safety. The proposed by DNURT without steaming technology of concrete sleepers production using domestic polycarboxylate concrete additives in combination with the use for screening of gravel the screening surface of new generation produced by PE «Logiya», will bring concrete sleepers of Ukrainian producers on the European level. Control of microstructural characteristics during the production process will prevent the mass premature destruction of concrete sleepers and sell products of Ukrainian concrete sleeper production plants to the European consumers. At this the proposed method of quality control of concrete is non-destructive and does not require disabling the newly made concrete sleepers.

81-95

Authors: T. М. Vasetska

Purpose. In the study it is supposed: 1) to extend the classical method of analytic hierarchy process (AHP) for a great number of alternatives and criteria; 2) to build a model of constructive decision making process using a modified method of analytic hierarchy process with sorting (AHPS). Methodology. To achieve this purpose the mechanism of constructive and productive structures (CPS) was used; the refining transformations of the generalized constructive-productive structure (GCPS) were fulfilled. Findings. The developed model of the constructive process is the interaction between the three structures: the general CPS of AHPS, which allows to set criteria and alternatives and performs the decomposition of task hierarchical structure; CPS of grouping and sorting, which divides alternatives (criteria) into groups and implements the classic single-level AHP for each group, as well as calculates estimates of paired comparisons based on the input data; CPS of single-level classic AHP, which allows to fill the matrix of paired comparisons and calculates the ranks of alternatives. All three structures interact at different levels of transformations: by data conformity at the level of concretization and using of implementations. The proposed model allowed moving to the more abstract level in presentation of decision making problem solving for a great number of criteria and alternatives. Originality. The paper proposes to use CPS mechanism for formalizing modifications of AHP with sorting for decision making problem solving with a great number of criteria and alternatives. Practical value. The formalization of the presentation of the analytic hierarchy process and its modifications allows extending the range of applications of this method, as well as unifying the description of various AHP modifications. Such presentation provides the possibility for developing the programs to implement the method hybrid modifications. Using different interpretations presented in the article of CPS will allow for other approaches in determining the coherence of pairwise comparison matrices, estimate calculation and ranks of alternatives and criteria.

116-124

Authors: S. M. Vasilyeu, A. D. Zheleznyakov, L. P. Tselkovikova

Purpose. The study investigates: 1) long cargo movements, carried on coupling of two railway platforms equipped with turnstile-fastening devices (TFD); 2) the forces acting on the cargo by the TFD. Methodologhy. Research were carried out using oscillations theory of mechanical systems with a finite number of degrees of freedom. Findings. Authors obtained rational parameters of TFD at dry friction in supports, which provide the smallest forces acting on the cargo as a result of impact. Oringinality. Early studies of «car – cargo» system dynamics with moving TFD were carried out with insufficient accuracy. When considering such tasks one resorted to a significant simplification of the calculation schemes. The use of such devices allows producing supports of long cargo for cars movable-centered ones. TED allow more or less significant shift of the cargo relatively to support cars in the longitudinal direction. After impact the return of the goods in the original position is ensured. Restoring force in such devices is formed either by the elastic properties of TED, either by increasing the center level relying on them masses. The return process takes place by the kinematic way when horizontal deflection of TFD from the equilibrium position. The solution of the problem to determine the nature and magnitudes acting on the cargo forces and accelerations is implemented by mathematical model, adequate to real conditions. Gaps limitations and absorbing apparatuses of the cars in TFD are taken into account. Practical value. This study will allow to calculate the parameters of real TFD that will reduce the damage of long cargo transported on coupling of railway platforms.

134-141

Authors: S. V. Myamlin, O. A. Kirilchuk, V. S. Metyzhenko

Purpose. The work is devoted to the study of horizontal oscillation and the assessment of the motion stability of a single wheelset with independent wheel rotation, and to the comparison of stability indicators of the typical wheelset and the wheelset with independent wheel rotation. This is connected with the necessity to increase traffic speed of rolling stock, improve road safety and comfort of passengers. Methodology. To achieve this purpose we used the methods of mathematical simulation of railway rolling stock dynamics, as well as the linear algebra methods to assess the stability of solutions of the linear homogeneous differential equations. Findings. To solve the set task the design model of a single wheelset with independent wheel rotation was created. The wheelset is not a single solid body; each of the wheelset axles has a surplus degree of freedom. Thus, we obtained the system with 4 degrees of freedom. The design model allowed to obtain the system of linear homogeneous differential equations describing the oscillations of the represented wheelset in a horizontal plane on a straight track section. On the basis of the computer modeling were calculated the eigenvalues of the differential equation system coefficients and the asymptotic stability analysis of the wheelset motion with independent wheel rotation. The increment and the frequency of fluctuations were compared with similar indicators for the standard wheelset. The authors also discussed non-oscillatory forms of the wheelset motion and the issues of wheelset self-centering on the track. Originality. The result of the work is the mathematical model of the sinuous movement of a single wheelset, in two-dimensional formulation, with independent wheel rotation and the estimate of the dynamic indices during its motion on a straight track section without any irregularities. There were also proposed the ways to ensure the self-centering on the track of the wheelset with independent wheel rotation. Practical value. The developed mathematical model of the single wheelset motion with independent wheel rotation can be used to create the advanced designs of railway running gear of cars.

151-160

Authors: V. V. Kachurenko, D. O. Bannіkov

Purpose. The paper aims: 1) qualitative assessment of the nature of the container corrugated wall deformation caused by the load from bulk materials. 2) determination of the horizontal pressure redistribution scheme for each individual corrugation plate and the calculation method that is closer to the real situation. 3) obtaining the quantitativedeformation indicators to compare them with the calculated ones produced by means of mathematical model simulation. Methodology.To achieve this purpose the different types of capacitive structure profiles were investigated and the values of total vertical displacement under load were obtained. The computational experiment used the design computer system Structure CAD for Windows. In addition, the laboratory experiment was conducted, the analysis of which is important to confirm the correctness of pre-made computer models. Findings. The conducted experiment allowed receiving the confirmation of the FEM calculated data, namely qualitatively and quantitatively the deformation direction and nature completely repeated the design situation in SCAD. Thework ofcorrugatedprofile was analysedfordifferenttheoreticallypossibleload schemesanddifferentcalculation methods. Alsotheworkcontainstherecommendationsfortherealcalculationusingcomputersimulation. During a joint study the authors obtained the data that allow for more accurate assessment of the corrugated profile performance under the pressure from bulk materials. Originality. The conducted research and experimental tests explain and clarify the ways for possible redistribution of bulk material pressure on each corrugation plate, while there is no such information in the existing recommendation literature and regulatory framework concerning the capacitive structure design. Practical value.The use of the proposed solutions is useful for correct design of containers with corrugated walls during further calculations and search of new directions for future research.

169-175

Authors: D. V. Rudenko

Purpose. The article considers definition of the bond types occurring in a modified cement concrete matrix, and the evaluation of the quality of these links in a non-uniform material to determine the geometrical and physical relationships between the structure and the cement matrix modifiers. Methodology. To achieve this purpose the studies covered the microstructure of dispersed modified concrete cement matrix, the structure formation mechanism of the modified cement concrete system of natural hardening; as well as identification of the methods of sound concrete strength assessment. Findings. The author proposed a model of the spatial structure of the concrete cement matrix, modified by particulate reinforcement crystal hydrates. The initial object of study is a set of volume elements (cells) of the cement matrix and the system of the spatial distribution of reinforcing crystallohydrates in these volume elements. It is found that the most dangerous defects such as cracks in the concrete volume during hardening are formed as a result of internal stresses, mainly in the zone of cement matrix-filler contact or in the area bordering with the largest pores of the concrete. Originality. The result of the study is the defined mechanism of the process of formation of the initial strength and stiffness of the modified cement matrix due to the rapid growth of crystallohydrates in the space among the dispersed reinforcing modifier particles. Since the lack of space prevents from the free growth of crystals, the latter cross-penetrate, forming a dense structure, which contributes to the growth of strength. Practical value. Dispersed modifying cement matrix provides a durable concrete for special purposes with the design performance characteristics. The developed technology of dispersed cement system modification, the defined features of its structure formation mechanism and the use of congruence principle for the complex of technological impacts of physical and chemical processes of hydration of clinker minerals allowed developing technological bases for special-purpose concrete.