scholarly journals Locomotive Reliability Assessment Method

2022 ◽  
Author(s):  
P. Gubarev
Keyword(s):  
Analytical Form ◽  
Assessment Method ◽  
Reliability Estimation ◽  
Normal Operation ◽  
Rolling Stock ◽  
Reliability Indices ◽  
Event Distribution ◽  
Control Procedures ◽  
Technical Specifications ◽  
Definition Of

Abstract. The authors describe the analysis of the current state of the problem under consideration. A definition of "averaged failure flow parameter" is given. The periods of traction rolling stock life cycle are considered. The assumption of event distribution laws exponentiality is introduced, which makes it possible to obtain expressions of the main reliability indices in the analytical form. The work of depot service locomotives to ensure the required reliability and readiness of the rolling stock during their normal operation has been assessed. The introduction of the term "readiness" into the modern practice of traction rolling stock reliability estimation is considered. The initial data for calculating the indexes of locomotive uptime and readiness are presented. Calculated values of readiness and no-failure indices of electric locomotives in operation are obtained. The calculated values of internal and technical availability coefficients are compared with similar indicators established by technical specifications. Control procedures were performed to determine the compliance of each set of locomotives (EP1, 2ES4K) with the uptime requirements. As a result of comparing the calculated values of internal and technical availability factors (for electric locomotives EP1 and 2ES4K with analogous values set by specifications (EP1 and 2ES4K) it was determined that the surveyed locomotives comply with the established availability requirements. As a result of control procedures to determine the compliance of each set of EP1 and 2ES4K locomotives with the uptime requirements, it was determined that the set of 2ES4K electric locomotives for the run in question does not fully comply with the uptime requirement. And the set of EP1 electric locomotives meets the reliability requirements, but the error value is higher than 20%. To clarify both events, it is necessary to increase the mileage interval of the locomotives and repeat the procedure for determining compliance with the uptime requirements. The method of assessing the uptime and readiness of locomotives during their normal operation makes it possible to identify existing shortcomings in the operation of rolling stock and to form measures to improve the quality of rolling stock operation.

scholarly journals MODEL OF AN ESTIMATION OF A RESOURCE OF TRACTION TRANSFER OF A MOTOR CARLOAD ROLLING STOCK

2015 ◽  
Vol 2 (158) ◽  
Author(s):  
Aleksandr Babanin ◽  
Sergiy Yarovoy ◽  
Vadim Bulba
Keyword(s):  
Life Cycle ◽  
Service Life ◽  
Motor Block ◽  
Technical Condition ◽  
Normal Operation ◽  
Rolling Stock ◽  
Definition Of ◽  
Analytical Expressions

In clause questions of definition of a resource of the wheel motor block traction transfer of a motorcarload rolling stock are considered. Problems of forecasting of a technical condition of responsible units oftraction transfer are certain. The model of deterioration in which the periods extra earnings are allocated,normal operation, intensive deterioration and prolongation of service life of the wheel motor block of amotor carload rolling stock is formalized for weigh his life cycle. For each allocated period meetingdependences of speed and intensity of deterioration are offered. According to dependences calculations arelead and analytical expressions of wear of points of cog-wheels of power reducing of traction transfer whichallow to predict his resource in operation are received.

scholarly journals Rail safety in the context of relationships between directives on safety and interoperability - analysis from the point of view of the essential requirements of the essential 'security'

2016 ◽  
Vol 2016 (12) ◽  
pp. 17-26
Author(s):  
Marek Pawlik ◽  
Marcin Kowalski
Keyword(s):  
Point Of View ◽  
Rolling Stock ◽  
Electrical Safety ◽  
Essential Requirement ◽  
Safety Requirements ◽  
Control Command ◽  
Technical Specifications ◽  
Definition Of ◽  
Traction Power Supply ◽  
Supply Systems

The article presents relationships between railway safety directive and railway interoperability directive. The carried out analysis starts from the definition of the railway interoperability and is based on essential requirement of ‘safety’. Ten safety requirements areas were indicated, which are contained in the Technical Specifications for Interoperability TSIs. The article takes into account: degraded situations, construction safety, electrical safety, protection against unauthorised access and fire, influence of forces from rolling stock on track and wheel-rail stability requirements, control command and signalling, influence of traction power supply systems on signalling equipment, operational rules and staff qualifications, panic countervail, as well as informatics support for safety. The article complements analyses, which will be presented in the following issue of the journal.

Analysis on Coal Transportation Network Invulnerability Based on Edge Failure

2014 ◽  
Vol 919-921 ◽  
pp. 1075-1078
Author(s):  
Li Na Sun ◽  
Hong Sheng Sun ◽  
Ya Long Zhao
Keyword(s):  
Crucial Role ◽  
Transportation Network ◽  
Assessment Method ◽  
Normal Operation ◽  
Transport Networks ◽  
Coal Transportation ◽  
Edge Failure ◽  
Definition Of ◽  
Attack Strategy ◽  
Integrated Transport Network

Coal transportation network is mainly integrated transport network of rail, road and waterway transport modes composed. Transport routes play a crucial role for transport networks normal operation. This paper combine with the definition of coal transportation network invulnerability based on edge failure and attack strategy, proposing invulnerability assessment method, combining with China's coal transportation network to analyze network invulnerability in case of side failure.

scholarly journals Prevalence and risk factors of delirium and subsyndromal delirium in older adults

2021 ◽  
Vol 33 (1) ◽  
Author(s):  
Maha Hosam El-Din Ibrahim ◽  
Manal Elmasry ◽  
Fady Nagy ◽  
Ahmed Abdelghani
Keyword(s):  
Risk Factors ◽  
Older Adults ◽  
Functional Ability ◽  
Cognitive Assessment ◽  
Length Of Hospital Stay ◽  
Assessment Method ◽  
Assessment Tools ◽  
Subsyndromal Delirium ◽  
Confusion Assessment ◽  
Definition Of

Abstract Background Delirium is a common geriatric problem associated with poor outcomes. Subsyndromal delirium (SSD) is characterized by the presence of certain symptoms of delirium yet, not satisfying the definition of full-blown delirium, defined by categorical elements, and is usually referred to as the presence of one or more symptoms in the confusion assessment method (CAM). This study aimed to investigate the prevalence and risk factors of delirium and SSD in older adults admitted to the hospital. Five hundred eighty-eight elderly (above 65 years) Egyptian patients were recruited from January 2019 to February 2020. After explaining the purpose of the study and assuring the confidentiality of all participants, an informed consent was obtained from the participant or a responsible care giver for those who were not able to give consent. All patients were subjected ‘on admission’ to thorough history taking, clinical examination, and comprehensive geriatric assessment including confusion assessment tools, mini-mental state examination, and functional assessment using Barthel index score. Results The current study showed that 19.6% of patients had delirium and 14.1% of patients had SSD with combined prevalence of 33.7%. Most common causes included metabolic, infection, organic brain syndrome, and dehydration. The current study reported significant proportionate relation between cognitive assessment and functional ability, so patients with a score of 23 MMSE had good functional ability, while cognitive assessment using mini-mental score shows inversed relation to delirium and SSD using CAM score. Conclusion Delirium is independently associated with adverse short-term and long-term outcomes, including an increase in mortality, length of hospital stay, discharge to an institution, and functional decline on discharge. Subsyndromal delirium (SSD) is characterized by the presence of certain symptoms of delirium, not yet satisfying the definition of full-blown delirium but it can identify patients with early cognitive and functional disabilities, and because of high prevalence of delirium and SSD. Efforts to prevent or early detection may identify patients who warrant clinical attention.

Food Allergy-Related Bullying Among Children and Adolescents

2021 ◽  
Author(s):  
Frances Cooke ◽  
Ashley Ramos ◽  
Linda Herbert
Keyword(s):  
Food Allergy ◽  
Social Inclusion ◽  
Assessment Method ◽  
Assessment Methods ◽  
Clinical Trial Registration ◽  
Single Item ◽  
Parents And Children ◽  
Bullying Experiences ◽  
Definition Of ◽  
Parent Child

Abstract Objective Food allergy (FA) management requires youth to avoid allergens and carry emergency medication which can impact participation in social activities. Previous research indicates that some youth experience FA-related bullying, but many studies are limited by single-item assessment methods and a narrow definition of bullying. This study describes FA-related bullying among a diverse cohort of youth with FA and evaluates parent–child disagreement and bullying assessment methods. Methods Youth ages 9–15 years (n = 121) diagnosed with an IgE-mediated FA and their primary caregivers were recruited from pediatric FA clinics to complete surveys about their FA-related bullying experiences. Descriptive statistics were conducted to assess overall FA-related bullying and McNemar tests were utilized to assess disagreement among parent–child report and between multi-item and single-item assessment methods. Results Seventeen percent and 31% of youth reported FA-related bullying on single-item and multi-item assessments, respectively. Twelve percent of parents reported their child had experienced FA-related bullying. Youth reported overt physical (51%), overt non-physical (66%), and relational FA-related bullying (20%). FA-related bullying was most common among classmates. Assessment method significantly affected the rates of FA-related bullying reported by youth, and parents and youth only agreed on FA-bullying experiences when assessed via the single-item measure. Conclusions A subset of a diverse sample of youth with FA reported FA-related bullying. Clinicians should use multi-item assessment methods and ask both parents and children about their experiences to fully capture the experiences of families managing FA. School policies that facilitate FA safety and social inclusion should be promoted. Clinical Trial Registration N/A.

DEVICE REALIZATION OF MAGNETIC METHOD FOR DEFINITION OF METAL STRENGTHENED LAYER THICKNESS IN ROLLING-STOCK AXLE

2021 ◽  
Vol 2021 (2) ◽  
pp. 28-37
Author(s):  
Yuriy Livcov ◽  
Vladimir Bezkorovaynyy ◽  
Andrey Kireev
Keyword(s):  
Magnetic Properties ◽  
Layer Thickness ◽  
Metal Layer ◽  
Rolling Stock ◽  
Magnetic Method ◽  
Cold Plastic Deformation ◽  
Natural Experiments ◽  
Micro Hardness ◽  
Scattering Field ◽  
Definition Of

The simplest and accessible method for rolling-stock axle surface strengthening is surface processing with cold plastic deformation by means of rolling. This process is one of the stages in manufacturing diesel locomotive and car axles of a rolling-stock. The basic parameters of rolling engineering process are micro-hardness of a metal surface strengthened layer and its depth, which at present are controlled by means of cutting out longitudinal polished specimens from the axle and in case of the deviation from the required value the whole set axles is rejected. That is why there is offered a method of the non-destruction control of micro-hardness and depth of axle strengthening the essence of which is not only in the control of a strengthening degree value, but in the instant correction of rolling equipment in case of the deviation from the parameter, as this device is integrated in the interface of a rolling machine. In such a way, an actual value of strengthened layer micro-hardness will be always within the specified limits. The principle of device operation is based on the topography changes in the scattering magnetic field of preliminary magnetized local volume of ferromagnetic material. There are shown numerical experiments for the dependence parameter definition of a scattering field of a magnetic mark from thickness and magnetic properties of a strengthened metal layer which had given a possibility to obtain the analytical dependences of a strengthened layer thickness and coercive force of the strengthened layer upon the parameters of a horizontal and vertical constituents of the scattering field strength of the magnetic mark. There are obtained results of natural experiments which allow defining magnetic properties of the upper metal layer in the axle and checking the correctness of data obtained at numerical computations, computation errors do not exceed 6%. The integration circuit of the mentioned structure-scope in the configuration of a rolling machine to obtain a feedback on a micro-hardness value of a surface strengthened layer.

scholarly journals Mathematical model of pantograph cooperation with two degrees of freedom with a catenary system

2019 ◽  
Vol 294 ◽  
pp. 05005
Author(s):  
Marek Kaniewski ◽  
Michał Cichoński
Keyword(s):  
Mathematical Model ◽  
Discrete Model ◽  
Degrees Of Freedom ◽  
Variable Stiffness ◽  
System Model ◽  
Dynamic State ◽  
Rolling Stock ◽  
Two Degrees Of Freedom ◽  
Technical Specifications ◽  
Catenary System

The authors present a method of modeling pantograph cooperation with a catenary system by means of a computer program based on a pantograph discrete model with two degrees of freedom and a catenary system model as a focused mass that in the dynamic state has variable stiffness along the span. After performing the appropriate tests, the validation was carried out according to the proposed method in the PN EN 50318:2019-02 standard required in the Technical Specifications for the interoperability of the subsystem “Energy” and “Rolling stock -locomotives and passenger rolling stock” of the trans-European rail system in Europe.

A Tool for the Design and Evaluation of Alternative Quality-Control Procedures

1992 ◽  
Vol 38 (2) ◽  
pp. 204-210 ◽  
Author(s):  
Aristides T Hatjimihail
Keyword(s):  
Quality Control ◽  
Systematic Error ◽  
Power Function ◽  
Error Detection ◽  
Simulation Program ◽  
Analytical Process ◽  
Defect Rate ◽  
Control Procedures ◽  
Definition Of ◽  
Design Comparison

Abstract I have developed an interactive microcomputer simulation program for the design, comparison, and evaluation of alternative quality-control (QC) procedures. The program estimates the probabilities for rejection under different conditions of random and systematic error when these procedures are used and plots their power function graphs. It also estimates the probabilities for detection of critical errors, the defect rate, and the test yield. To allow a flexible definition of the QC procedures, it includes an interpreter. Various characteristics of the analytical process and the QC procedure can be user-defined. The program extends the concepts of the probability for error detection and of the power function to describe the results of the introduction of error between runs and within a run. The usefulness of this approach is illustrated with some examples.

Treating Epistemic Uncertainty Using Bootstrapping Selection of Input Distribution Model for Confidence-Based Reliability Assessment

2019 ◽  
Vol 141 (3) ◽  
Author(s):  
Min-Yeong Moon ◽  
K. K. Choi ◽  
Nicholas Gaul ◽  
David Lamb
Keyword(s):  
Physical System ◽  
Epistemic Uncertainty ◽  
Bootstrap Method ◽  
Reliability Assessment ◽  
Assessment Method ◽  
Reliability Estimation ◽  
Distribution Model ◽  
Hierarchical Bayesian ◽  
Distribution Models ◽  
Input Distribution

Accurately predicting the reliability of a physical system under aleatory uncertainty requires a very large number of physical output testing. Alternatively, a simulation-based method can be used, but it would involve epistemic uncertainties due to imperfections in input distribution models, simulation models, and surrogate models, as well as a limited number of output testing due to cost. Thus, the estimated output distributions and their corresponding reliabilities would become uncertain. One way to treat epistemic uncertainty is to use a hierarchical Bayesian approach; however, this could result in an overly conservative reliability by integrating possible candidates of input distribution. In this paper, a new confidence-based reliability assessment method that reduces unnecessary conservativeness is developed. The epistemic uncertainty induced by a limited number of input data is treated by approximating an input distribution model using a bootstrap method. Two engineering examples and one mathematical example are used to demonstrate that the proposed method (1) provides less conservative reliability than the hierarchical Bayesian analysis, yet (2) predicts the reliability of a physical system that satisfies the user-specified target confidence level, and (3) shows convergence behavior of reliability estimation as numbers of input and output test data increase.

scholarly journals Definition of Alloy Substitute Thermal Capacity Using the Simple Macrosegregation Models

2012 ◽  
Vol 12 (4) ◽  
pp. 113-116 ◽  
Author(s):  
B. Mochnacki
Keyword(s):  
Solid State ◽  
Mathematical Description ◽  
Energy Equation ◽  
Analytical Form ◽  
Thermal Capacity ◽  
Thermal Processes ◽  
Volumetric Fraction ◽  
Macro Scale ◽  
The One ◽  
Definition Of

Abstract Mathematical description of alloys solidification in a macro scale can be formulated using the one domain method (fixed domain approach). The energy equation corresponding to this model contains the parameter called a substitute thermal capacity (STC). The analytical form of STC results from the assumption concerning the course of the function fS = fS (T) describing the changes of solid state volumetric fraction and the temperature at the point considered. Between border temperatures TS , TL the function fS changes from 1 to 0. In this paper the volumetric fraction fS (more precisely fL = 1- fS ) is found using the simple models of macrosegregation (the lever arm rule, the Scheil model). In this way one obtains the formulas determining the course of STC resulting from the certain physical considerations and this approach seems to be closer to the real course of thermal processes proceeding in domain of solidifying alloy.

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