bluuebunny/crossref_metadata_2025 huggingface dataset:
Vibration analysis as an auxiliary tool for monitoring the safety and viability of production equipment in mechanical engineering
Authors: Akhtulov Alexey , Ivanova Ludmila
Published: December 2020

The paper considers the influence of dynamic loads that occur in industrial equipment of machine-building production on the conditions of its safe operation and viability, as well as on humans.
On the possibility of individual forecasting of reliability factors of mechanical transport units
Authors: Savin L O , Novikov A N
Published: December 2020

The paper considers an approach to predicting probabilistic characteristics of the time before the transition of critical MT units to a failure state, based on the use of quasi-deterministic models of the time drift of the parameters monitored during maintenance. This approach makes it possible to ensure implementation in practice of flexible maintenance of MT strategies in relation to various conditions of its operation.
Mathematical model for engineering tracked vehicle suspension system connections influence assessment
Authors: Sarach Evgeniy , Ivanov Aleksey , Kurasova Mariya , Tkachev Yaroslav
Published: December 2020

This paper is devoted to designing imitational mathematical model that can help in tracked vehicle, which has connected suspension system, motion smoothness research. In this paper advantages and disadvantages of existing mathematical models are analyzed which allow to evaluate different design choices expediency at designing stage. In order to take suspension system connections into consideration and evaluate the possibility of using the created mathematical model to study transport vehicle motion smoothness the existing rectilinear motion mathematical model, created by BMSTU scientists, was modified. Modeling was carried out in MATLAB Simulink program complex. The results of connected suspension system imitational mathematical model usage are demonstrated on solving the following problem: tracked vehicle motion smoothness comparison in case of using connected and independent suspension system. These results show that connections in suspension system, which were added to decrease chassis loads, do not influence the tracked vehicle motion smoothness in any way. Thus, the modified imitational mathematical model can be used for tracked vehicle, which has connected suspension system, motion smoothness research.
Efficiency assessment in transport service provision for the population of Orel city
Authors: Kulev M V , Kulev A V , Kuleva N S
Published: December 2020

The article discusses the main methods for quality of passenger traffic assessment, presents the main advantages and disadvantages of these methods. The questionnaire for interviewing passengers was developed, which includes questions about the gender and age of passengers, their social standing, the frequency of passenger transport use and its attractiveness to consumers. The efficiency of city public transport functioning assessment methodology based on the results of a survey of passengers using elements of the “Google Forms” service was also offered in the article.
Differential pressure sensor for hydraulic drive of traction vehicles
Authors: Fomenko N A , Burlachenko O V , Lyashenko A A
Published: December 2020

Hydraulic systems equipped with working bodies hydraulic drive are widely used in road construction, agricultural, reclamation, forestry, military-technical and other surface vehicles. Depending on the operating conditions and modes, hydraulic drive elements are subjected to self-destruction, for example, high-pressure hoses hydraulic system, which reduces the machines’ working life (resource), increases operating costs and worsens the environmental situation. There are various systems and methods for protecting the hydraulic drive to militate these negative consequences. The analysis of conditions, operating modes and factors affecting the machines’ hydraulic system state, methods and systems for protecting the hydraulic drive, the causes of high-pressure hoses of destruction and the negative impact of consequences on the environment shows that the problem of finding a new technical solution remains. A new design solution is proposed for protecting the hydraulic drive, which is equipped with two adjustable throttles, two reverse valves and a pressure drop sensor that includes a diaphragm forming the positive and negative chambers.
Study of relationship between lateral slip coefficient and indicators of tire linear stiffness
Authors: Abdulgazis A U
Published: December 2020

Based on the analysis of the recent study, the article delves into the unresolved problem of defining the influence of normal and lateral stiffness coefficients on the tire lateral slip. The authors propose a method to determine such influence of normal and lateral stiffness on the tire lateral slip coefficient. The obtained analytical expressions make it possible to calculate the lateral slip coefficients of the tires taking into account their design parameters, speed, normal and tangential reactions in the wheel road contact spot.
Vibroacoustic debugging technique for vehicle exhaust systems
Authors: Okunev A P , Ovchinnikov V A , Cherepanov L A , Epishkin V E
Published: December 2020

Influence of the exhaust system on the vibroacoustic comfort of a passenger car with a transverse power unit is considered. The methodology is presented which, when using road tests and calculating the exhaust system on the finite element model, allows to reduce the levels of vibration and noise from the exhaust system when changing to more powerful engines in serial passenger cars.
Impact of the variable stiffness section on the conditions of track and rolling stock interaction
Authors: Kurhan D , Kurhan M , Husak M
Published: December 2020

Railway track stiffness is one of the main parameters that determine the track and rolling stock interaction. The inelasticity of the rail base may occur for two reasons: either as a consequence of the deteriorated condition of a track or due to the structural features of a section. As a rule, areas before bridges or tunnels are treated. Today, there are several options for relevant design solutions. The main purpose of this work is to determine the characteristics of a “railway track” object with which it can be represented in the rolling stock models in the simplest way possible but adequate for sections of transient stiffness. The railway track is introduced into the rolling stock model as a sequence of elements with which the wheels of the rolling stock interact. It is assumed that a single element in its characteristics must be equivalent to the track response when passing the wheel from one inter-sleeper section to the next one, that is, to reproduce a sequence that is cyclically repeated. Such a track element will be characterized by reduced mass, stiffness and dissipation factor.
Problems of the use of renewable energy sources in the structure of railway power supply
Authors: Ostapchuk Oleksandr , Kuznietsov Mykola , Kuznetsov Valeriy , Kuznetsov Vitaliy
Published: December 2020

The paper presents the main indicators of the renewable energy sources in the railway transport structure of European countries. A new structure of railway power supply systems, energy storage systems and control algorithms under the conditions of stochastic mode of renewable energy sources operation are defined as the main problematic issues. Further directions for sustainable development of such systems and factors that influence the modes of operation of traction substations and electric networks were identified. Average power and a random component are two criteria that were used to build local systems. The paper presents the real schedules of daily load on the traction substation terminals and solar insolation with determined power distribution changes. The power deviations indicators depending on the time interval and the type of generation were determined. A normal law of distribution of a random component was determined as a result of all calculations. It is possible to determine the shortage or excess of electric power in the local system in a certain area and to plan the direction of its development in the near future by analyzing the nature of the determined average power change.
Study of railway traffic safety based on the railway track condition monitoring system
Authors: Kliuiev S , Medvediev Ie , Khalipova N
Published: December 2020

The solution to the problem of monitoring the railway track, as well as potentially dangerous objects and phenomena in the adjacent territories, is determined by the need to implement increased requirements for traffic safety (primarily to the geometric parameters of the devices of a long railway track under construction and functioning load-bearing highways), prevention of technological disasters and large-scale negative effects of natural phenomena on the railways. The continuous process of integrating methods and means of monitoring and preventing emergencies into a single information management system is shown. The possibility of determining a dynamic model of the adverse effect of the train on the track and the most unfavorable for the track train and traction parameters, which must be avoided when forming trains in this section, is established. Three key factors are formulated, the use of which will reduce the negative impact on the track from trains. The concept of information technology improvement of the monitoring system for potentially dangerous sections of the railway on the basis of new innovative technologies has been developed.
To the problem of train running safety
Authors: Pshinko O M , Ursulyak L V , Zhelieznov K I , Shvets A O
Published: December 2020

The paper is presenting the procedure used for establishing the cause of the wagon derailment. To do this, the computer simulations and the computational software, developed in the Dnipro National University of Railway Transport (DIIT) were used. The level of longitudinal forces and the wagons dynamic performance have been evaluated using the mathematical models of longitudinal oscillations of a train and the spatial vibrations of wagons, in particular of tank wagons. As a result of modeling we obtained oscillograms of longitudinal forces in each inter-wagon connection, the dependence of the largest longitudinal forces on travel time and distance traveled, the distribution of the maximum longitudinal forces along the train length, the speed dependence on travel time and track coordinates. We also obtained the dynamic performance of wagons: the vertical dynamics coefficients of the axle-box and central suspension, the horizontal dynamics coefficients and the derailment stability coefficient. The influence of the movable load in the tank wagons and the characteristics of rail irregularities on the stability coefficient against wheel climbing onto the rail is also considered. The presented methodology was used to determine the cause of the tank wagon derailment in a non-homogenous freight train consisting of 50 wagon tanks on an existing track section of the Lithuanian railways. When simulating the train movement, it was assumed that the train was equipped with elastic-friction absorbing devices and air distributors, turned on to the average operation mode. As a result of numerical experiments, an assumption was made about the cause of the train derailment.
Track circuits adjusting calculation method under current influence traction interference and electromagnetic compatibility
Authors: Razghonov S , Kuznetsov V , Zvonarova O , Chernikov D
Published: December 2020

The problem of railway transport electromagnetic compatibility automation systems in recent years has been aggravated by the use of power frequency converters in electric transport drives, which significantly increase the efficiency of traction characteristics of 3-phase electric engine. However, estimate relevant harmonic levels in the frequency range used in track circuits of railway automation and telemechanic systems. The paper provides theoretical justification for practical measurements of interference. It is shown, that the interference coefficients monotonically increase in the following cases: 1) increase in the value of the harmonic frequency; 2) increase in the propagation constant, taking into account the supports resistance of the contact network; 3) increase in the circuits track length. Operating frequencies of tonal track circuits up to 800 Hz, the interference increase rate in given length of the rail circuit slows down. The increase in interference coefficients depending on the mentioned factors is explained by the fact that with current part growth of the harmonic flows from the traction substation through the earth increases and thereby creates currents asymmetry of the track circuits.
Reducing of coal dust release from train wagon with barrier
Authors: Biliaiev M M , Biliaieva V V , Kozachyna V A , Berlov O V , Oladipo M O , Kirichenko P S
Published: December 2020

Intensive environment pollution takes place during coal transportation in open wagons. Emission of coal dust from the coal wagons cause contamination of atmosphere and territory adjacent to the railway track. Different ways to reduce coal dust emission from the wagon are used in the world. Unfortunately, in Ukraine, this problem is far from solution and there is no serious research work in this field. The aim of this work was laboratory study of coal dust emission from the wagon model which had different barriers installed on the wagon. Laboratory experiments were carried for coal wagon without barrier and for coal wagon which had barriers of two types. Barrier of the first type had downwind wing. Barrier of the second type had upwind wing. The contamination zones, concentration near the model were studied. The obtained results illustrate that installation of barriers influence intensity of transport corridor contamination. Also a numerical model was developed to estimate wind flow and coal dust dispersion from the coal wagon. Equation of potential flow and equation of coal dust dispersion were used. Implicit difference schemes of splitting were used for numerical simulation of governing equations. Results of numerical experiment, which were performed, are presented.
The results of brake tests of the DPKr-3 diesel train
Authors: Dovhaniuk S , Shaposhnyk V , Shykunov O , Shatunov A , Visloguzov V
Published: December 2020

JSC “Ukrzaliznytsia” purchased the first of three planned regional three-car (two main motor cars and one intermediate) diesel train DPKr-3 manufactured by PJSC “Kryukovsky railway car building works”. To confirm the declared characteristics and safety indicators of the DPKr-3 diesel train, specialists department of Cars of Dnipro National University of Railway Transport named after Academician V. Lazaryan conducted complex certification tests, which confirmed the compliance of the stated parameters. One of the points of the Terms of Reference was to determine the brake pressure of the linings per 100 weight of the train in terms of cast iron brake pads. For this purpose, according to the methodology adopted in the territory of the former CIS, force sensors, which were installed in the tick mechanisms instead of the brake linings, measured the magnitudes of the forces of pressing the brake linings on the disks. However, during the tests it was found out that the current standards for calculating the provision of train brakes cannot be applied to modern rolling stock. It is recommended for rolling stock where the use of brake pads, and even more cast iron, is not provided by the design, to develop normative documents that would determine the standards for brakes by the results of calculations and tests.
Optimal Control Method of High-Voltage Frequency Converters with Damaged Cells
Authors: Busher V , Chornyi O , Glazeva O , Kuznetsov V G , Tytiuk V , Tryputen M
Published: December 2020

Application of high-voltage frequency converters is one of the most prospective trends in the development of current powerful electric drives, i.e. in high-speed trains. In terms of such converters, a multilevel cascaded H-bridge converter is becoming the most widespread one owing to its increased reliability, survival in terms of one or more damaged cells, and quick repairability due to its modular structure. The research proposes a control method, which provides maximum possible linear voltage in case of one or several damaged cells owing to the shift of zero point and turning of phase voltages. It is also demonstrated how turning angles of phase voltages should be set to preserve spatial position of the linear voltage vectors which provides the least complicated electromagnetic transients in terms of nominal rotation frequency; in case of low or middle frequencies, damage of the cells may have no effect on the motor operation. Fast algorithm to calculate turning points of phase voltages is proposed; the algorithm may be applied in the industrial microprocessor control systems. Algorithm of the operations, which provides implementation of the method, is described.
Mathematical modeling of shock wave interaction with wagon
Authors: Khrutch V K , Biliaiev M M , Kozachyna V A , Berlov O V , Kirichenko P S , Biliaieva V V
Published: December 2020

In case of some accidents on railways there may be situations when the shock wave appears and interacts with different objects on the railway (wagons, cargo, buildings etc.). In these cases it is necessary to predict the possible effect of shock wave diffraction on the different objects. Study of these problems on the basis of physical experiments (laboratory experiment or field experiment) demand expensive and unique experimental facility. In some cases physical experiment can’t be set. That is why mathematical simulation plays the important role in solving problem connected with shock wave propagation. For practice it is necessary to have predictive quick computing mathematical models which allow to perform numerical experiment on the basis of non-powerful computers. Now, in Ukraine, there is a real deficit of mathematical models which allow to compute quickly shock wave interaction with different objects. The aim of this work was development of quick computing numerical model to simulate shock wave propagation and its interaction with the wagons. The model is based on the numerical integration of Euler equations which are written in integral form. To solve modeling equations difference scheme of splitting was used. Results of numerical modeling are presented.
Energy efficiency of heat tests for traction electric machines
Authors: Afanasov A M , Shapovalov O S , Holik S N , Arpul S V , Bilukhin D S
Published: December 2020

The article discusses one of the options to reduce the electricity consumption for the carry out acceptance of post-repair tests of traction electric machines. Heating tests of traction electric machines at the mutual load stand are the most energy-intensive part of the entire test program. Energy consumption for this type of test can be reduced, for this, an analysis of thermal processes in the windings of traction electric machines during their heating test was given. The energy efficiency coefficient of the mutual load system is formulated. The energy efficiency coefficient for the traction electric machine NB-406 is calculated. The calculation results showed that with an increase in the test current by 30%, the total losses in the motor windings decrease by about one and a half times, while the test time decreases by almost three times. An increase in test current and a decrease in test time do not reduce the quality of the test, and the results obtained. A methodology for assessing the energy efficiency of heating tests is proposed. It can be applied at test sites of depots, as well as repair plants. This will reduce the material costs of testing, without compromising the quality of the tests themselves.
Research of the modern absorbing apparatus power characteristics influence on the freight train inter-car forces
Authors: Shimanovsky A O , Sakharau P A , Kuzniatsova M G
Published: December 2020

A mathematical model of the inter-car connections used in the long and heavy train is presented. It takes into account the elastic-frictional properties of absorbing devices and gaps in automatic coupler devices connecting the train cars. There are demonstrated the calculation results of a homogeneous train motion along a straight horizontal track section at such non-steady modes as at starting, braking by the locomotive electrodynamic brakes and passing along a track profile section of a complex shape. A comparative assessment of the influence of the kind of the absorbing devices power characteristic on the maximal longitudinal forces arising in the train inter-car connections is carried out using the MSC ADAMS engineering software package. Transients with a smooth and sharp change in traction and braking forces are considered. Based on the obtained results, the main positive and negative properties of rigid, linear and soft power characteristics of the automatic couplers’ absorbing devices used on the railway rolling stock are determined. The results of performed computer simulation can be applied to the sphere of design and modernization of absorbing devices of automatic couplers and to the process of composition of various types of cars in trains of any length and weight.
Stand for accelerated tests of rail vehicles wheelsets
Authors: Raksha S , Anofriev P , Kuropiatnyk O
Published: December 2020

Tests and research can be greatly accelerated by applying a multi-point load to the test wheel. The aim of this work is to substantiate rational parameters of the stand for accelerated life tests of railway wheelsets, in which a multi-point load applies to the rolling surface of the test wheel. On the basis of the laws of the theory of elasticity, we performed analytical calculations of the contact stresses created by the rolling bodies of the load mechanism of the test stand. Research has shown that the dependence of the contact stresses on the wheel rolling surface on the ball’s diameter is nonlinear. The decrease in stress is due to an increase in the contact area. We obtained the analytical and graphical dependencies, which make it possible to evaluate the influence of the parameters of the stand for accelerated life tests of railway wheelsets on contact stresses on the wheel rolling surface, taking into account the shape and dimensions of this surface. The authors have proposed a stand design for accelerated life tests of railway wheelsets. The use of a stand with the parameters justified in this work will reduce the test duration by 10-15 times.
Theory development for determination of rational parameters of the capacitive energy storage for a metro train
Authors: Sulym A O
Published: December 2020

In the article a comparative analysis of existing methodologies and approaches on the parameters determination of the capacitive energy storages for a metro train with energy recovery systems was performed, disadvantages of each of them were determined. A complex approach for estimation of the on-board capacitive energy storage parameters was proposed; the point of approach consists in determination of the rational power and energy capacity for two parameters of the storage system at once – mass and payback period. The complex approach is based on theoretical researches, which require simulation of the metro train equipped with recuperation system operation by mean of developed software. The objective function was represented and boundary values for the power and energy capacity during determination of the rational parameters of the on-board capacitive energy storage using a complex approach were specified. The recuperation system with rational parameters of the on-board capacitive energy storage for specified service conditions in Public Utility Company “Kyiv Metropolitan” and chosen research metro train was specified. Amount of energy stored due to the installation of the energy storage system with rational parameters was estimated.
A new method to create of the plane section standards of grain metal structures
Authors: Danilenko T
Published: December 2020

A new method to create of the plane section standards of grain metal structures with a previously known size distribution of 3D grains is proposed. A quantitative analysis of G3, G4, G5 indices of the standard ISO 643:2012 was performed. The stereological modeling method taking into account the polyhedral shape of 3D grains was used to create new versions of plane section standards. Versions of 3D grains structures as the diameter size distributions of 3D grains, plane sections of which correspond to the main quantitative characteristics of existing G3, G4, G5 indices have been created. It was shown that these versions should contain 3D grain more than 1.5 times the mean diameter of the corresponding plane sections. Choosing the diameter size distributions of 3D grains, necessary for the standard, its possible to create a visual index as a picture, as it done on the existing standard, and also to give the parameters of 3D structure, plane section of which corresponds to this standard. Using a new approach to creating standards will increase the accuracy of the grain structure parameters determining.
Feasibility study of using permanent magnets as indirect temperature monitor in irradiation capsule of nuclear research reactor
Authors: Saurav Suman , Muthuganesh M. , Chaurasia P. K. , Murugan S.
Published: December 2020

In sodium cooled nuclear fast reactors, materials used for fuel cladding and structural components can undergo significant physical and dimensional changes due to exposure to high energy neutrons. At high temperature and radiation conditions prevailing in the nuclear reactor, material properties change considerably. Information about the temperature of exposure during specimen irradiation in a nuclear reactor is important since the temperature is having a strong influence on the mechanical and physical properties of materials. A proper evaluation of the effects due to radiation on materials needs a precise knowledge of the irradiation temperature. Many times, standard techniques for measuring temperature are not practicable in reactors due to the availability of limited instrumented positions. Therefore, the use of small-sized indirect temperature monitors such as melt wires, permanent magnets, etc. which can be incorporated along with the samples and examined after the irradiation are preferred. In the present study, permanent magnets of neodymium grade N38 and N38SHX of different sizes have been studied for their possible use as an indirect temperature monitor. The study was carried out first for their compatibility with sodium since the monitor will be exposed to sodium during irradiation experiments in fast reactors, and then by exposing to different temperatures in an electrical furnace for the determination of Curie point to study the feasibility of using these materials as indirect temperature monitors. Since the material loses its magnetic properties when the temperature of exposure exceeds the Curie point, by using a series of magnets having progressively increasing curie points, the temperature of exposure can be determined by testing these magnets for the retention of their magnetic properties. Specifically, since there is variation in the Curie temperature as reported in the literature, the experimental method was developed to determine the Curie temperature accurately. This paper discusses the details of the experiments carried out in our laboratory and the results obtained from these studies.
Theoretical and experimental modal analysis of centrifugal pump radial flow impeller
Authors: Oza M N , Shah D S
Published: December 2020

Modal analysis is extensively used to identify the dynamic properties of a structure in terms of the dynamic characteristics: natural frequency, damping factor and mode shape. In this research, modal analysis has been carried out on a radial flow impeller of a centrifugal pump. The 3-D model of the impeller was built in CAD software Creo Parametric 1.0 from a 2-D drawing and that model was imported in FEA software package ANSYS for conducting modal analysis. The model was meshed effectively using SOLID187 elements. The first twenty natural frequency and mode shapes were extracted and nodal diameter was identified for each mode shape. The experimental modal analysis was conducted using impact hammer and the first twenty natural frequencies were identified using FFT analyzer. The natural frequencies of both the methods were compared and it was found that there is a good agreement between these results, thus the FE model is validated. The results are discussed and conclusions drawn.
Experimental investigation on the mechanical properties of wood sawdust and plaster of paris reinforced composite
Authors: Singh Avinash , Muniappan A
Published: December 2020

In this work the wood saw dust and plaster of paris have been reinforced to form a new composite material. The materials which have been used are wood saw dust and plaster of paris. Wood saw dust is a derivative of several operations on wood such as drilling, routing, sanding, milling, sawing, planning etc. and plaster of paris is made from gypsum. Gypsum is heated at 373 K in a furnace to lose some water content and thus POP (plaster of paris) is formed. Both materials are mixed together with the help of water to form a paste and are freezed at 0°C for 24 hours. And three different samples are made by varying the ratio of sawdust and plaster of paris. The samples are obtained in the 15cm x 15cm x 3.5cm dimensions by using a plastic box and is given in the laboratory for testing various properties such as density, ash content, hardness, compression load, hardness at -40°C etc. Three different samples are in the ratios (WSD: POP): 3:1, 1:1, 1:3 are obtained. Out of three the third sample gives the best result and can be used as a construction material in cold places.
Design of reduced dipole yagi – Uda antenna
Authors: Muthu Kannan P. , Reji M. , Swaminathan R.
Published: December 2020

This work provides design and analysis of a dipole antenna whose height is reduced. Any Dipole antenna can be designed with λ/2 height. A half wave dipole is formed with ‘λ/2’ height to get desirable characteristics of dipole antenna. Minimizing antenna height is always a desirable in antenna design. Hence, an attempt is made in this work to reduce the height of a dipole and as an application, Yagi-Uda antenna is constructed using this reduced dipole and optimized for better gain. The results are discussed in detail.
Influence of nano SiO2 in cement mortar using taguchi analysis
Authors: Vasanthi P , Senthil Selvan S
Published: December 2020

In this research, optimization technique was employed to optimize the nano SiO2 in cement mortar preparation by using Taguchi-technique. The main aim of this present investigation is to find the optimal input variables like nano SiO2, w/c ratio and plasticizer to achieve cement mortar with high compressive strength and low water absorption percentage. When the input variables are more than one Taguchi - technique approach is a best method since it may give difference set of optimum level for each response. It is found that the addition of nano SiO2, in cement mortar influenced high compressive strength with lower water absorption percentage. According to analysis nano-silica of 2wt. %, w/c ratio of 0.5 and plasticizer of 1wt. % (A2, B3 and C2) is found to be producing highest compression strength of 51.45MPa and lower water absorption percentage of 2.95.
Development and studies of new rolling screw-type mechanisms
Authors: Blinov D S , Morozov M I
Published: December 2020

One of the tendencies in mechanical engineering is the transition from sliding friction to rolling friction in part joints moving under load, motor assemblies and machinery. For the present time, planetary roller screws (PRS), which are rolling mechanisms, possess the biggest potential as converters of rotational motion to linear motion. However production of high-precision parts for PRS requires special expensive equipment. The emerging world tendency for reduction of technological costs is to develop nutless roller screws (NRS), which is the most complex PRS part to manufacture. Its production requires an additional machine tool or a universal grinding machine for external and internal grinding. The new rolling NRS has been developed in line with this tendency. This paper focuses on the design and operation of the mechanism and on theoretical studies. A test model and a testing rig have been developed to confirm the results of the theoretical studies and to determine operation parameters of the new NRS. The experiments showed that the newly developed NRS loses to PRS in some parameters, while outperforming it in other. It is also simpler and cheaper to produce and after additional studies and tests rational applications for the newly developed NRS can be found.
Diagnostics of dissipative characteristics of friction damper
Authors: Chernyshev S L , Kolesnikov V I , Vermel V D , Ozyabkin A L , Kolesnikov I V , Koryakin A N
Published: December 2020

The aim of our study was to broaden current knowledge of characteristics of friction damper that acts to dissipate the energy of small translational oscillations in friction pairs and to convert it into significant angular shaft movements. We have devised a novel methodology to evaluate elastic-dissipative characteristics of the damper, which provides real-time identification of the stability of these characteristics, as well as running-in periods, stable operation, and catastrophic wear. It is shown that plan bearings made of antifriction self-lubricating organic-fiber composite are more effective than plain bearings made of metal-fluoroplastic tape since their use causes less high-frequency noises that affect the quality of transient response.
Modelingof stress-strain state of a pneumatic tire in Abaqus software at stationary rolling
Authors: Korolev P V , Shilov M A , Maslov L B , Fomin S V
Published: December 2020

The paper presents a step-by-step development of a finite element model of stationary rolling of a radial automobile tire on a surface, where friction is taken into account. The method of finite element modeling (FEM) is used to determine the influence of the method of setting the rolling of a pneumatic tire on its performance properties. The authors come to the conclusions about the advisability of using various methods for creating models of pneumatic tires and give recommendations for optimization of the numerical experiment.
On the prospects of research in the field of evaluation and reduction of mining machines elements wear
Authors: Pobegailo P A , Gadolina I V , Gustov Ju A
Published: December 2020

In this paper, the authors present some considerations on how to develop studies of wear (wear resistance) of mining machines for open-pit mining. First, the need to continue research aimed at adapting the A.K. Reisch’s approach was noted to clarify and improve the empirical formula to assess the wear rate of elements of mining and road machines. Secondly, it is planned to deepen research to assess the correlations between the properties of materials used in mining engineering and characteristics of their wear resistance. Thirdly, the problem of wear of elements of mining machines is considered from the standpoint of managing the phenomenon of wear. For this, the A.K. Reisch’s empirical formula can be used, and the optimization problem formulated in a general form, which is reduced to maximizing the productivity of the machine with restrictions on the rate of wear of its elements and the operating costs. Fourth, the relationship between the problem of managing the phenomenon of wear and the dynamics of mining machines is noted. Some of these researches are illustrated by examples of a qualitative nature.
Evaluation of the influence of lubricant quality on dynamic performance and resource of involute gears
Authors: Polyakov S A , Kuleshova E M , Kuksenova L I , Medovshchikov A V
Published: December 2020

The article deals with the relationship between the occurrence of self-oscillations and the wear process in involute gears. The dependence of the amplitude of the torque fluctuations on the high-speed shaft of the involute gears on the type of lubricant is presented. The calculation of the transmission service life is given, taking into account the rate of growth of the dynamic coefficient.
Metal cladding of friction surfaces in liquid media
Authors: Shapovalov V V , Migal Yu F , Ozyabkin A L , Burakova M A , Feizova V A , Korniyenko R A
Published: December 2020

On the basis of the quantum-chemical method, the possibility of using a liquid lubricant containing a fine powder of the Al-Mg-Li system is considered. It provides a high-quality process of metal cladding of steel friction surfaces and, as a result, an increase in the resource of a single application of a liquid lubricant and the resource characteristics of the tribological system “wheel rail”.
Abrasive wear of metal surface modified with mineral particles
Authors: Skazochkin A V
Published: December 2020

The resistance of mineral coatings created on the surface of specimens of 20X13 steel (Russian analogue of steel 20Cr13 (EU)) modified with ultradispersed mineral particles to abrasive wear during friction against fixed particles was determined, and the wear parameters of layers modified with mineral particles were compared with the parameters of surface layers created by laser cladding of alloys of different compositions. The studies were carried out on an experimental setup for testing abrasive wear under a static load of 60 N and 160 N and determined the weight wear, the average wear rate and the average wear rate of the surface layer of three samples with different mineral coatings. According to the results of measurements at a pressure on the wear surface of 0.5 MPa, a sample was determined with an indicator of weight wear comparable to a coating made of cobalt alloy, created by the method of laser cladding and about four times inferior in this indicator, to a coating of a nickel alloy, created by the method of laser cladding and tool steel. The practical use of various methods of protecting parts from abrasive wear is determined, along with the physical and technical characteristics of the layers, by the economic feasibility in specific operating conditions.
Prospects for the use of high-speed ESP for oil production
Authors: Smirnov N I , Skvortsova E S
Published: December 2020

Increasing the ESP speed allows for a reduction in the linear dimensions of the units and the number of standard sizes. By reducing the length, wear resistant materials can be used in each pump stage. However, with an increase in the rotational speed to 10000 rpm, the head of the pumping stage increases significantly (> 35m) and the processes of friction and wear intensify. Test benches for wear testing of pump stages and thrust bearings of hydraulic protectors and submersible electric motors with a rotation speed of up to 12000 rpm have been developed. It was revealed that the greatest change in mass is observed in the guide vane due to erosive wear, which varies depending on the rotational speed in a power-law dependence with an exponent of ∼ 3.4. When testing a thrust bearing made of SiC with a rotational speed of 10800 rpm and an axial force of 6000N, the friction coefficient varied in the range 0.028 ... 0.008. Bearing made of hard alloy WC-8Co scored at 4.92MPa load. It is necessary to determine the optimal area of application of high-speed ESPs and the allowable wear values of the pump stages.
Tribological studies of carbon seal materials at cryogenic temperatures
Authors: Smirnov N I , Prozhega M V , Smirnov N N , Petrov A V , Chernenko D N
Published: December 2020

The results of the tribological properties studies of composite materials at cryogenic temperatures are presented in the present paper. Test equipment has been developed, friction and wear tests have been carried out at a temperature of T = - 196 °C. The test results showed a significant dependence of the composite material wear rate on the load.
Bioactive Sr2+/Fe3+ co-substituted hydroxyapatite in cryogenically 3D printed porous scaffolds for bone tissue engineering
Authors: Yang Liang , Ullah Ismat , Yu Keda , Zhang Wancheng , Zhou Jinge , Sun Tingfang , Shi Lei , Yao Sheng , Chen Kaifang , Zhang Xianglin , Guo Xiaodong
Published: December 2020

Developing multi-doped bioceramics that possess biological multifunctionality is becoming increasingly attractive and promising for bone tissue engineering. In this view innovative Sr2+/Fe3+ co-substituted nano-hydroxyapatite with gradient doping concentrations fixed at 10 mol% has been deliberately designed previously. Herein, to evaluate their therapeutic potentials for bone healing, novel gradient SrFeHA/PCL scaffolds are fabricated by extrusion cryogenic 3D printing technology with subsequent lyophilization. The obtained scaffolds exhibit desired 3D interconnected porous structure and rough microsurface, along with appreciable release of bioactive Sr2+/Fe3+ from SrFeHA components. These favorable physicochemical properties render printed scaffolds realizing effective biological applications both in vitro and in vivo, particularly the moderate co-substituted Sr7.5Fe2.5HA and Sr5Fe5HA groups exhibit remarkably enhanced bioactivity that not only promotes the functions of MC3T3 osteoblasts and HUVECs directly, but also energetically manipulates favorable macrophages activation to concurrently facilitate osteogenesis/angiogenesis. Moreover, in vivo subcutaneous implantation and cranial defects repair outcomes further confirm their superior capacity to dictate immune reaction, implants vascularization and in situ bone regeneration, mainly dependent on the synergetic effects of released Sr2+/Fe3+. Accordingly, for the first time, present study highlights the great potential of Sr7.5Fe2.5HA and Sr5Fe5HA for ameliorating bone regeneration process by coupling of immunomodulation with enhanced angio- and osteogenesis and hence may provide a new promising alternative for future bone tissue engineering.
Amplification of polarization correlations in Compton scattering of hard x-ray Bell states
Authors: Caradonna Peter
Published: December 2020

The theoretical cross section for Compton scattering of maximally entangled Bell photons has yet to be rigorously confirmed by experiments. Test cases of Bell states for use in Compton scattering experiments can now be expanded given reports of creating all 4 Bell states in the hard x-ray regime by the process of spontaneous parametric down-conversion. We outline an experiment and apply a matrix method to parameterize Compton scattering theory using the phase matching angles. When the azimuths of two hypothetical photon counters are recorded at angles of 0 degrees and 90 degrees, and the ratio of their counting rates determined, azimuthal ratios are expected to be 600 times larger compared to 511 keV Bell photons.
Promoting of direct electron transfer of multicopper oxidase by control of enzyme molecule density on multi-walled carbon nanotube
Authors: Takamura Eiichiro , Ohnishi Taku , Sakamoto Hiroaki , Satomura Takenori , Suye Shin-ichiro
Published: December 2020

In order to improve the performance of direct electron transfer-type electrode using multicopper oxidase (MCO), it is important to shorten the distance between the redox site of the enzyme and the electrode surface to increase electron transfer efficiency between enzyme and electrode. In this study, we focused on the mobility of the MCO from hyperthermophilic archaeon, Pyrobaculum aerophilum, immobilized onto electrode surface via an affinity tag at the MCO terminus. The mobility of the immobilized enzyme was controlled by changing the density of the immobilized enzyme on the electrode surface by altering the density of the linker for enzyme immobilization. The electrode with low density of MCO immobilized on electrode surface was improved swing ability of the enzyme. It showed 265% higher current density for electrochemical O2 reduction than that with high density of MCO immobilized on electrode surface. Biofuel cell using a cathode with a low density of MCO immobilized on the electrode showed 160% higher power density than a biofuel cell using a cathode with a high density of MCO immobilized on the electrode.
Machine learning for neutron scattering at ORNL*
Authors: Doucet Mathieu , Samarakoon Anjana M , Do Changwoo , Heller William T , Archibald Richard , Alan Tennant D , Proffen Thomas , Granroth Garrett E
Published: December 2020

Machine learning (ML) offers exciting new opportunities to extract more information from scattering data. At neutron scattering user facilities, ML has the potential to help accelerate scientific productivity by empowering facility users with insight into their data which has traditionally been supplied by scattering experts. Such support can help in both speeding up common modeling problems for users, as well as help solve harder problems that are normally time consuming and difficult to address with standard methods. This article explores the recent ML work undertaken at Oak Ridge National Laboratory involving neutron scattering data. We cover materials structure modeling for diffuse scattering, powder diffraction, and small-angle scattering. We also discuss how ML can help to model the response of the instrument more precisely, as well as enable quick extraction of information from neutron data. The application of super-resolution techniques to small-angle scattering and peak extraction for diffraction will be discussed.
Machine learning for analyzing and characterizing InAsSb-based nBn photodetectors
Authors: Glasmann Andreu , Kyrtsos Alexandros , Bellotti Enrico
Published: December 2020

This paper discusses two cases of applying artificial neural networks to the capacitance–voltage characteristics of InAsSb-based barrier infrared detectors. In the first case, we discuss a methodology for training a fully-connected feedforward network to predict the capacitance of the device as a function of the absorber, barrier, and contact doping densities, the barrier thickness, and the applied voltage. We verify the model’s performance with physics-based justification of trends observed in single parameter sweeps, partial dependence plots, and two examples of gradient-based sensitivity analysis. The second case focuses on the development of a convolutional neural network that addresses the inverse problem, where a capacitance–voltage profile is used to predict the architectural properties of the device. The advantage of this approach is a more comprehensive characterization of a device by capacitance–voltage profiling than may be possible with other techniques. Finally, both approaches are material and device agnostic, and can be applied to other semiconductor device characteristics.
Graph networks for molecular design
Authors: Mercado Rocío , Rastemo Tobias , Lindelöf Edvard , Klambauer Günter , Engkvist Ola , Chen Hongming , Jannik Bjerrum Esben
Published: December 2020

Deep learning methods applied to chemistry can be used to accelerate the discovery of new molecules. This work introduces GraphINVENT, a platform developed for graph-based molecular design using graph neural networks (GNNs). GraphINVENT uses a tiered deep neural network architecture to probabilistically generate new molecules a single bond at a time. All models implemented in GraphINVENT can quickly learn to build molecules resembling the training set molecules without any explicit programming of chemical rules. The models have been benchmarked using the MOSES distribution-based metrics, showing how GraphINVENT models compare well with state-of-the-art generative models. This work compares six different GNN-based generative models in GraphINVENT, and shows that ultimately the gated-graph neural network performs best against the metrics considered here.