scholarly journals Mathematical modelling and analysis of thermometric diagnostics of electrical products

2018 ◽  
Vol 226 ◽  
pp. 04037
Author(s):  
Danil V. Shaykhutdinov ◽  
Konstantin M. Shirokov
Keyword(s):  
Continuous Monitoring ◽  
Active Component ◽  
Magnetic Characteristic ◽  
Technical Condition ◽  
Test Time ◽  
Thermal Processes ◽  
Actual Problem ◽  
Special Measuring ◽  
The Mathematical Model ◽  
Source Of Information

The actual problem is the diagnosis and monitoring of the technical condition of the machines in operation, as well as the forecasting of their technical condition. The complexity of the problem of condition controlling is that the most informative characteristics of the electrical products can not be accurately determined without the use of special measuring transducers, which considerably increases the test time and makes it difficult to carry out continuous monitoring. A promising direction in solving this problem is the use of sensorless methods. Implementing these methods is based on using as a source of information the working winding of the electrical product, the active component of the resistance of which is determined just before the measurement of the magnetic characteristic and then used as a constant value. In the process of testing, there is heating and, as a consequence, a change in the active component of the winding resistance, which causes an unacceptable errors in determining the electrical products state. In this article the mathematical model of thermal processes are developed and analysis of thermometric diagnostics of electrical products is carried out.

scholarly journals Application of Laser Vibrometry to Assess Defects in Ship Hull’s Welded Joints’ Technical Condition

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 895
Author(s):  
Adam Szeleziński ◽  
Adam Muc ◽  
Lech Murawski ◽  
Marcin Kluczyk ◽  
Tomasz Muchowski
Keyword(s):  
Optical Sensors ◽  
Welded Joints ◽  
Measurement Data ◽  
Technical Condition ◽  
Laser Vibrometer ◽  
Laser Vibrometry ◽  
Destructive Testing ◽  
Laser Sensors ◽  
Measurement Methodology ◽  
The Mathematical Model

The paper presents the measurement process and test results for six thin-walled plates with different dynamic characteristics caused by different defects of welded joints. The tests were carried out using non-destructive testing (NDT). The authors made an attempt to determine the validity of the use and degree of effectiveness of the tests based on laser vibrometry in detecting defects in welded joints. The tests of welded plates were carried out using displacement laser sensors and piezoelectric accelerometers, while the source of vibration extortion was a modal hammer. In the adopted measurement methodology, the application of accelerometers was to obtain the reference data, which allowed for comparison with the measurement data obtained from the laser vibrometer. The analysis of the obtained measurement data, in the fields of time and frequency, made it possible to verify the correctness of the data obtained by means of laser vibrometry and to determine the requirements which are necessary for the correct performance of NDT tests and in the future structural health monitoring (SHM) system of welded joints with the use of a laser vibrometer. The mathematical model developed in the MSC software Pastran-Nastran was also used in the work. The model was developed for the purpose of mutual verification of the measurement and calculation tests. At the present stage of work, it can be stated that the results obtained by laser vibrometry methods should be treated as a supplement to the research conducted with traditional piezoelectric accelerometers. In certain situations, they can be used as an alternative to accelerometers, due to the fact that laser sensors do not require direct contact with the examined object. Where the object under test may be in a strong electromagnetic field, optical sensors are better suited than contact sensors.

scholarly journals Step-by-step control of target efficiency indices of the control and measuring equipment stock applied in construction and housing and communal services

2018 ◽  
Vol 170 ◽  
pp. 01010 ◽  
Author(s):  
Rustam Khayrullin ◽  
Pavel Ivanov
Keyword(s):  
Mathematical Model ◽  
Finite Difference ◽  
Measuring Equipment ◽  
Technical Condition ◽  
Measuring Instruments ◽  
Finite Difference Equations ◽  
Target Values ◽  
The Mathematical Model ◽  
Step Control ◽  
Different Levels

The mathematical model is considered for the formation and implementation of development strategies of the stock of control and measuring instruments (CMI) applied in construction and housing and communal services(HCS), and step-by-step control of efficiency target values of the stock. The model is based on a system of finite - difference equations describing the change of number of the CMI samples with different levels of technical perfection and technical condition at each planning interval. The model allows calculating the required number of CMI for procurement and repairs in the various groups for provide target values of efficiency indices at each planning interval. Controller is number of modern CMI samples for procurement and number of modern and obsolete faulty CMI samples for the repairs. The results of calculations are presented.

scholarly journals Diagnostics of supercapacitors

2018 ◽  
Vol 182 ◽  
pp. 01009 ◽  
Author(s):  
Valeriy Martynyuk ◽  
Oleksander Eromenko ◽  
Juliy Boiko ◽  
Tomasz Kałaczyński
Keyword(s):  
Mathematical Model ◽  
Mathematical Models ◽  
Methodological Approach ◽  
Frequency Dispersion ◽  
Technical Condition ◽  
Transient Processes ◽  
Nonlinear Frequency ◽  
Diagnostic Reliability ◽  
General Reliability ◽  
The Mathematical Model

The paper represents the mathematical model for diagnostics of supercapacitors. The research objectives are the problem of determining a supercapacitor technical condition during its operation. The general reliability of diagnostics is described as the methodological and instrumental reliabilities of diagnostics. The instrumental diagnostic reliability of supercapacitor includes the probabilities of errors of the first and second kind, α and β respectively. The methodological approach to increasing the reliability of supercapacitor diagnostic has been proposed, in terms of multi-parameter supercapacitor diagnostic by applying nonlinear, frequency dependent mathematical models of supercapacitors that take into account nonlinearity, frequency dispersion of parameters and the effect of transient processes in supercapacitors. The more frequencies, operating voltages and currents are applied in the supercapacitor diagnostics, the more methodological reliability of diagnostics will increase in relation to the methodological reliability of supercapacitor diagnostics when only one frequency, voltage and current are applied.

Exact Solutions of the Vibration Problem of Beam Structures

2013 ◽  
Vol 390 ◽  
pp. 242-245 ◽  
Author(s):  
Alexander V. Chekanin
Keyword(s):  
Mathematical Model ◽  
Exact Solutions ◽  
Dynamic Characteristics ◽  
Natural Frequencies ◽  
Numerical Solutions ◽  
High Accuracy ◽  
Displacement Method ◽  
Actual Problem ◽  
Beam Structures ◽  
The Mathematical Model

The article deals with the actual problem of improving the accuracy of determining the dynamic characteristics of beam structures. To solve such problems the displacement method is used. Defining matrices are calculated with the Godunovs scheme. Numerical solutions in this case can be obtained practically with any accuracy within accepted hypotheses of the mathematical model of the calculated object. This suggests that the resulting solutions are standard. The examples of determining the natural frequencies of vibrations of beam structures that demonstrate an extremely high accuracy of the proposed algorithm are given.

scholarly journals Mathematical analysis of the effect of the constant temperature assumption in the leak test of PTB Testing Instructions, Volume 25

ACTA IMEKO ◽  
2018 ◽  
Vol 7 (1) ◽  
pp. 68
Author(s):  
Oscar Yazit Salah García ◽  
Carlos Eduardo García Sánchez
Keyword(s):  
Constant Temperature ◽  
Flow Rate ◽  
Test Time ◽  
Leak Test ◽  
Maximum Value ◽  
Critical Nozzles ◽  
S Model ◽  
The Mathematical Model ◽  
Allowable Temperature ◽  
Test Result

<p class="Abstract">"PTB Testing Instructions, Volume 25: Gas meters – Test rigs with critical nozzles" (PTB 25) includes a detailed description of a test to evaluate the tightness of the rig (leak test). The mathematical modeling of this test assumes that temperature remains constant, and it is established a maximum allowable change of 0.1 K during the test. PTB 25 defines a maximum value of the leak flow rate as criteria for approval of the test.</p><p class="Abstract">In this work, the effect of the assumption of constant temperature over the leak test result was analyzed. Different processes in which the real leak flow rate was zero and there was a change in the temperature of the system equal to the maximum permissible (according to PTB 25) were simulated, and the leak flow rate calculated by PTB 25’s model was determined. The assumption of constant temperature does not simplifies drastically the mathematical model. It is concluded that PTB 25’s maximum allowable temperature change is too high for most practical situations, leading to errors that exceeds the maximum allowable leakage rate. The factors “test time” and “enclosed volume” have a high effect over the magnitude of the error given by PTB 25’s leak flow rate model.</p>

scholarly journals Efficiency improvement of technical condition assessment of plunger pairs of diesel fuel equipment

2020 ◽  
Vol 329 ◽  
pp. 01018
Author(s):  
Anatolii Eremeev ◽  
Aleksandr Morozov ◽  
Dmitry Kotkov
Keyword(s):  
Diesel Fuel ◽  
Evaluation Process ◽  
Condition Assessment ◽  
Technical Condition ◽  
Test Time ◽  
Hydraulic Pressure ◽  
Efficiency Improvement ◽  
Pressure Test ◽  
Time Record

Usage of an upgraded device for assessing technical condition of plunger pairs makes it possible to increase assessment accuracy and reduce the number of erroneously rejected plunger pairs. The action of this device is based on introduction of automatic hydraulic pressure test time record into the evaluation process.

scholarly journals EXISTING APPROACHES TO THE MATHEMATICAL MODEL"INSULIN-GLUCOSE"

2020 ◽  
Vol 1 (27(54)) ◽  
pp. 4-7
Author(s):  
S.I. Kisil ◽  
T.S. Zaletova
Keyword(s):  
Mathematical Model ◽  
Blood Glucose ◽  
Mathematical Models ◽  
Blood Sugar ◽  
Continuous Monitoring ◽  
Monitoring Systems ◽  
The Mathematical Model

Algorithms for predicting blood glucose based on the use of mathematical models that can be used in continuous monitoring systems for blood sugar are described.

ABOUT DEPTH OF DRAINING ON SALTED LAND

2018 ◽  
pp. 5-8
Author(s):  
A Ramazanov
Keyword(s):  
Experimental Research ◽  
Continuous Monitoring ◽  
Diagnostic System ◽  
Scientific Work ◽  
Technical Condition ◽  
Reliable Operation ◽  
Improve Performance ◽  
Technical Status ◽  
Pumping Units ◽  
The Cost

One of the main requirements for reliable operation of pumping units is continuous monitoring, analysis of technical condition and timely troubleshooting. Development of modern and perfect ways to determine the technical status of pumping units to prevent the occurrence of malfunctions. This article presents the results of experimental research carried out in the laboratory on the basis of scientific work. Using the recommended diagnostic system makes it possible to assess the technical condition, improve performance and reduce the cost of repairing pumping units.

CUTTING TEMPERATURE WHEN PROCESSING WITH ELASTIC ABRASIVE WHEELS

2020 ◽  
pp. 55-60
Author(s):  
YU.V. Dimov ◽  
D.B. Podashev
Keyword(s):  
Mathematical Model ◽  
Cutting Force ◽  
Cutting Temperature ◽  
Polymer Binder ◽  
Thermal Processes ◽  
Abrasive Wheel ◽  
Processing Mode ◽  
Abrasive Grain ◽  
The Impact ◽  
The Mathematical Model

The thermal processes that occur during processing with elastic abrasive wheels (EAW) are analyzed. The calculation of heat from the impact of a single abrasive grain and the temperature of the billet during processing, which should be lower than the melting temperature of the EAW polymer binder, is proposed. The adequacy of the mathematical model is confirmed by experiments. Keywords: ELASTIC ABRASIVE WHEEL, MICRORELIEF, CUTTING FORCE, TEMPERATURE, PROCESSING MODE. [email protected]

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