Resource calculation of weared equipment for electric trains of the ES2G series

2020 ◽  
pp. 43-50
Author(s):  
A. A. Vorob’ev ◽  
◽  
S.O. Zyazev ◽  
Keyword(s):  
Comparative Analysis ◽  
Wear Rate ◽  
Wear Surface ◽  
Mathematical Expectation ◽  
Operating Time ◽  
Operating Conditions ◽  
Wheel Pair ◽  
Rolling Surface ◽  
Flange Thickness ◽  
The Impact

The article discusses the impact of operating conditions on the wear of the wheels for ES2G electric trains. Thanks to the information on the controlled parameters of the wheel pairs (rolling, flange thickness and rim diameter) of ES2G electric trains operated by the MCC (Moscow Central Circle ) and the Oktyabrskaya Railway, a comparative analysis of the wear surface intensities of the rolling surfaces for seamless-rolled wheelsets has been performed. The analysis of the dependences of the mathematical expectation for the controlled parameter on the operating time showed that the wear rate of the rim for the electric trains operated by the MCC is 2,9 % higher than by the Oktyabrskaya Railway. Similar results were obtained for milling bar (2,33 % ) and the ridge thickness (24,3). Based on the results , it was concluded that the wheelsets wear of the ES2G series electric trains differs significantly in the two compared sections of circulation. Electric trains serving the Oktyabrsky direction has the intensity wheel pair wear lower than the trains serving the MCC. This will allow more time before turning to restore the profile of the rolling surface. The estimated value for the durability indicator of 90 % of the resource before changing the wheel pairs for the maximum wear of the rim is 2 million km at the MCC and 4.4 million km at the Oktyabrskaya Railway.

scholarly journals Performance analysis of the working surface of the rails from test batches on the Test Loop of JSC “VNIIZhT”

2018 ◽  
Vol 77 (3) ◽  
pp. 141-148
Author(s):  
M. Yu. Khvostik ◽  
I. V. Khromov ◽  
O. A. Bykova ◽  
G. A. Beresten’
Keyword(s):  
Wear Resistance ◽  
Operating Time ◽  
Operating Conditions ◽  
Continuous Change ◽  
Wear Area ◽  
Railway Network ◽  
Operational Conditions ◽  
Rolling Surface ◽  
Test Loop ◽  
The Impact

The monitoring of railway rails damage on the railway network of the JSC “Russian Railways” as well as operational and polygon tests are conducted with the purpose of assessing the impact of operating conditions on the intensity of rails damage, obtaining initial data for forecasting rails failures. The increased intensity of rails wear on sites with a complex plan and profile leads to the fact that with a continuous change from the track, rails which have an underutilized service life of more than 20 % are retrieved. Polygon tests on the Test Loop of the JSC “VNIIZhT” near the Scherbinka station can provide the repeatability and reliability of the results, comparative tests are carried out under identical conditions and their duration is several times less than when tested at experimental sites under operational conditions. The results of the polygon tests of new differentially heat-strengthened rails did not reveal any advantages in the wear resistance of special purposed rails (laid in the recommended radius of the curve for its application) when comparing the rails of domestic manufacturers. Metal shelling out on the rolling surface of rails is the main reason for the removal of rails from test batches. The origin and development of defects of this kind is due to both violations of the technology of manufacturing rails, and because of violations of the current maintenance of the track. The metal stock in the area of the rail head of R65 type due to the increase in its dimensions positively affects the extension of the lifetime of the rails, reducing the cost of the life cycle and the rail itself, and the design of the track as a whole. When carrying out a separate study in order to obtain results characterizing the stability of high-quality rails to contact fatigue damage, it is advisable to optimize the conditions of the polygon tests, bringing them closer to operational ones. When forming the test results, it is necessary to expand the list of criteria for assessing the wear resistance of rails, supplementing it with the size of the wear area at the time of a certain operating time of the tonnage, with the introduction of this criterion into the appropriate methods for the polygon (operational) tests.

Analysis of Degradation Mechanisms of Gate Dielectrics Based on SiO2 in MOS Transistors

2020 ◽  
Vol 25 (6) ◽  
pp. 517-524
Author(s):  
D.A. Eliseeva ◽  
◽  
S.O. Safonov ◽  
◽  
Keyword(s):  
Mathematical Models ◽  
Gate Dielectric ◽  
Gate Dielectrics ◽  
Degradation Mechanism ◽  
Operating Time ◽  
Operating Conditions ◽  
Hole Injection ◽  
Operating Voltage ◽  
Mos Transistors ◽  
The Impact

Nowadays, the developed mathematical models, describing the degradation mechanism of the gate dielectric, permit to determine the value of the operating time to failure of a device depending on its internal properties and operating conditions. These models significantly reduce the time and material required for performing testing and processing of large amounts of experimental data. In the paper the gate dielectric gates based on SiO in n -and p -channel MOS transistors have been studied. It has been found that under the impact of the electric field the degradation of the gate dielectric with 5.3 nm thickness most likely occurs according to the thermochemical model ( E -model) and in case with 7 nm thickness dielectric- in accordance with the anode hole injection model (1/ E -model). The coefficients have been calculated and the analysis of the mathematical models, permitting to determine the service life gate dielectrics based on SiO with 7 nm thickness in n - and p -channel MOS transistors for different values, of their area, operating voltage and temperature, has been performed. This study can serve as a method for monitoring and determining the quality of the gate dielectrics of manufactured MOS transistors.

WEAR TESTING OF BUTTONS IN BITS FOR BLASTHOLE DRILLING

Tribologia ◽  
2018 ◽  
Vol 278 (2) ◽  
pp. 13-19 ◽  
Author(s):  
Rafał DUDEK ◽  
Krzysztof WŁADZIELCZYK
Keyword(s):  
Abrasive Wear ◽  
Blast Hole ◽  
Operating Time ◽  
Operating Conditions ◽  
Wear Testing ◽  
Hole Drilling ◽  
Drilling Process ◽  
Rock Mining ◽  
Drilling Rigs ◽  
The Impact

The article presents the results of the wear testing of buttons in selected types of bits with the diameter of 95 mm used for blast hole drilling in a rock mining. The purpose of the testing was to determine the type of the wear of peripheral and frontal buttons in the actual operating conditions of bits and the impact of selected parameters of the drilling process and of sharpening the buttons on their durability. Tests of button wear were carried out by the blasthole drilling in deposits of the Devonian and Triassic dolomites. For the blast hole drilling with tested bits, drilling rigs HSB 500 and HBM 60, equipped with down-the-hole impact mechanisms VKP 95-2 from the company Permon were used. Tests on the wear of buttons were carried out according to the adopted methodology, taking into account both their abrasive wear and wear through crushing or falling out. During the drilling of holes, every effort was made to use fixed values of parameters of the drilling process, except for the value of drill stem rotation speed, because one of objectives of the research was to determine its impact on the abrasive wear of tested bits buttons. The obtained results of tests proved that the predominant type of wear of button bits for blast hole drilling is an abrasive wear of frontal buttons, and regular sharpening of the buttons allows increasing the operating time of rock bits by up to 35%.

scholarly journals Modeling the processes of friction and wear under dynamic influences on the tribosystem

2020 ◽  
Vol 97 (3) ◽  
pp. 45-49
Author(s):  
A. Voitov ◽  
Keyword(s):  
Wear Rate ◽  
Coefficient Of Variation ◽  
Friction And Wear ◽  
Operating Time ◽  
Dynamic Effect ◽  
External Action ◽  
Volumetric Wear ◽  
Distribution Law ◽  
Sliding Speed ◽  
The Impact

On the basis of the performed analysis of works devoted to the increase in the wear rate due to the dynamic effect on the tribosystem, expressions were obtained for modeling the processes of friction and wear when changing the external influence. Based on the assumption that the dynamic impact obeys the normal distribution law, the coefficient of variation of the volumetric wear rate. The simulation of the change in the coefficient of variation when changing the load and sliding speed on the tribosystem, as well as the number of steps of changing the load and operating time at each stage. It was found that in the absence of fluctuations in the load and sliding speed, the coefficient of variation of the volumetric wear rate is 1. With an increase in the value of the standard deviation of the external action and the number of steps of change in the action, the coefficient of variation of the volumetric wear rate increases to values 2,59, those volumetric wear rate increases by 1,125 … 2,59 times. This is confirmed by experimental dependencies. The simulation results are adequate to the experimental results with a confidence level 0,9. Calculated modeling error for each series of experiments, which does not exceed 11,03 %. It was found that when changing the power of the bully tribosystem Wb, which is defined as the product of the load and the sliding speed, the coefficient of variation of the volumetric wear rate increases by 1,25 … 4,68 times. Taking into account the range of changes in the external impact and the operating time at each stage of change in the impact will provide information in the form of a coefficient of increasing the wear rate.

scholarly journals Influence of the axial loads of rolling stock on the contact-fatigue life of rails

2018 ◽  
Vol 77 (3) ◽  
pp. 149-156 ◽  
Author(s):  
V. S. Kossov ◽  
G. M. Volokhov ◽  
O. G. Krasnov ◽  
M. N. Ovechnikov ◽  
A. L. Protopopov ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Service Life ◽  
Contact Fatigue ◽  
Calculated Data ◽  
Operating Conditions ◽  
Rolling Stock ◽  
Axial Loads ◽  
Rolling Surface ◽  
Contact Fatigue Life ◽  
The Impact

Analysis of operational data for defective and highly defective rails showed that up to 25 % is the contact-fatigue defects. In connection with the development of heavy haul traffic on the Russian railways, it is relevant to determine the influence of cars with increased axial loads of 25 and 27 tf on the contact fatigue life of rails. The solution of this problem is set forth in this article. The Brown-Miller model of multi-axial fatigue was used in the calculation. This model is integrated into the Fatigue software system, which is tied to the Marc calculation system through Pat-ran. Since under operating conditions the wheel moves (rolls) along the rail on meandering trajectory, in computer modeling weight coefficients were taken into account that characterize the percentage of wheels in the cross-sectional areas of the rail. Calculations of contact fatigue life took into account the variability of vertical loads from the impact on the track of trains formed from innovative open cars with axial loads of 23.5, 25 and 27 tf under operating conditions, loaded with real loading blocks. According to the analysis of calculated data with an increase in axial loads from 23.5 to 25 tf, it is necessary to expect a decrease in the service life of rails in contact fatigue resistance by 19 %, with a further increase in axle loads of up to 27 tf per 32 %. Considering that the share of freight cars with axial loads of 25 tf does not exceed 15...20 %, then on the routes of its use the service life of rails should be expected to decrease by 3...4 %. The method proposed by the authors for predicting the contact fatigue life of rails with increasing axial loads is advisable to improve in part of the experimental determination of the fatigue and strength characteristics of rail steel from the degree of hardening of the rolling surface, its probabilistic properties and the use of the integral distribution law for vertical forces, taking into account the structure of the freight traffic passing through the section. The work was carried out according to the RFBR project 17-20 01088.

scholarly journals Performance Analysis of a Solar Cooling System with Equal and Unequal Adsorption/Desorption Operating Time

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6749
Author(s):  
Farkad A. Lattieff ◽  
Mohammed A. Atiya ◽  
Jasim M. Mahdi ◽  
Hasan Sh. Majdi ◽  
Pouyan Talebizadehsardari ◽  
...  
Keyword(s):  
Cooling System ◽  
Operating Time ◽  
Operating Conditions ◽  
Solar Cooling ◽  
Overall Heat Transfer Coefficient ◽  
Experimental Findings ◽  
Solar Cooling System ◽  
Adsorption Desorption ◽  
The Impact ◽  
Adsorption Systems

In solar-thermal adsorption/desorption processes, it is not always possible to preserve equal operating times for the adsorption/desorption modes due to the fluctuating supply nature of the source which largely affects the system’s operating conditions. This paper seeks to examine the impact of adopting unequal adsorption/desorption times on the entire cooling performance of solar adsorption systems. A cooling system with silica gel–water as adsorbent-adsorbate pair has been built and tested under the climatic condition of Iraq. A mathematical model has been established to predict the system performance, and the results are successfully validated via the experimental findings. The results show that, the system can be operational at the unequal adsorption/desorption times. The performance of the system with equal time is almost twice that of the unequal one. The roles of adsorption velocity, adsorption capacity, overall heat transfer coefficient, and the performance of the cooling system are also evaluated.

Corruption as “one‑stop‑shop”: theory and empirical analysis

2018 ◽  
pp. 32-51
Author(s):  
R. Yu. Kochnev ◽  
L. I. Polishchuk ◽  
A. Yu. Rubin
Keyword(s):  
Comparative Analysis ◽  
Business Environment ◽  
Enterprise Performance ◽  
Double Jeopardy ◽  
One Stop ◽  
The Commons ◽  
Public Production ◽  
Performance Project ◽  
The Impact ◽  
Sector Theory

We present the comparative analysis of the impact of centralized and decentralized corruption for private sector. Theory and empirical evidence point out to a “double jeopardy” of decentralized corruption which increases the burden of corruption upon private firms and weakens the incentives of bureaucracy to provide public production inputs, such as infrastructure. These outcomes are produced by simultaneous free-riding and the tragedy of the commons effects. The empirical part of the paper utilizes data of the Business Environment and Enterprise Performance project.

Assessment of small businesses activities in Ukraine

2019 ◽  
pp. 40-47
Author(s):  
Igor Ponomarenko ◽  
Kateryna Volovnenko
Keyword(s):  
Comparative Analysis ◽  
Statistical Analysis ◽  
Small Business ◽  
Small Businesses ◽  
Government Agencies ◽  
Small Enterprises ◽  
The Subject ◽  
Business Entities ◽  
The Impact ◽  
Micro Enterprises

The subject of the research is a set of approaches to the statistical analysis ofthe activities of small business entities in Ukraine, including micro-enterprises. The purpose of writing this article is to study of the features of functioningof small business entities in Ukraine. Methodology. The research methodology isto use a system-structural and comparative analysis (to study the change in thenumber of small enterprises by major components); monographic (when studyingmethods of statistical analysis of small businesses); economic analysis (when assessing the impact of small business entities on socio-economic phenomena andprocesses in Ukraine). The scientific novelty consists to determine the features ofthe functioning of small businesses in Ukraine in modern conditions. The influenceof the activities of the main socio-economic and political indicators on the activities of small enterprises in recent periods of time has been identified. It has beenestablished that there is flexibility in the development of strategies by small businesses in conditions of significant competition, which makes it possible to quicklyrespond to changing situations in specific markets. Conclusions. The use of acomprehensive statistical analysis of small businesses functioning in Ukraine willallow government agencies to develop a set of measures to optimize the activitiesof these enterprises, which ultimately will positively affect the strengthening oftheir competitiveness and will contribute to the growth of the national economicsystem.

Truck Tire Operating Temperatures on Flat and Curved Test Surfaces

2005 ◽  
Vol 33 (3) ◽  
pp. 156-178 ◽  
Author(s):  
T. J. LaClair ◽  
C. Zarak
Keyword(s):  
Flat Surface ◽  
Operating Temperature ◽  
Operating Conditions ◽  
Load Pressure ◽  
Truck Tire ◽  
Endurance Testing ◽  
Operating Temperatures ◽  
The Impact ◽  
Tread Rubber ◽  
Cylindrical Test

Abstract Operating temperature is critical to the endurance life of a tire. Fundamental differences between operations of a tire on a flat surface, as experienced in normal highway use, and on a cylindrical test drum may result in a substantially higher tire temperature in the latter case. Nonetheless, cylindrical road wheels are widely used in the industry for tire endurance testing. This paper discusses the important effects of surface curvature on truck tire endurance testing and highlights the impact that curvature has on tire operating temperature. Temperature measurements made during testing on flat and curved surfaces under a range of load, pressure and speed conditions are presented. New tires and re-treaded tires of the same casing construction were evaluated to determine the effect that the tread rubber and pattern have on operating temperatures on the flat and curved test surfaces. The results of this study are used to suggest conditions on a road wheel that provide highway-equivalent operating conditions for truck tire endurance testing.

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