Method to Evaluate the Resistance–Capacitance Voltage Divider and Uncertainty Analysis

The resistance and capacitance parameters of a resistance–capacitance divider may change due to factors such as long-term operation, internal insulation flashover, and dielectric breakdown, which will affect the measurement characteristics of the resistance–capacitance divider. Since it is difficult to separate the voltage divider, and because improper disassembly will damage the insulation of the equipment, measuring the resistance and capacitance parameters of a voltage divider non-destructively has always been a problem. In this paper, an indirect method for evaluating the resistance and capacitance parameters is proposed, and the uncertainty of measurement of this method is determined. Simulation and actual test results show that this method can be used to estimate the resistance–capacitance parameters and has a good level of measurement accuracy. Besides, through the uncertainty analysis, it is concluded that the proposed method can overcome measurement errors within a certain range and has high practicability. Finally, a very practical application scenario of the proposed method is given, showing that the proposed method has good economic significance.

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КОЭФФИЦИЕНТЫ ДЕГРАДАЦИИ ПРОЧНОСТИ СИЛОВЫХ ЭЛЕМЕНТОВ КУПОЛА ПАРАШЮТА ПОСЛЕ ДЛИТЕЛЬНОЙ ЭКСПЛУАТАЦИИ ИЛИ ХРАНЕНИЯ

Aerospace technic and technology ◽

10.32620/aktt.2019.5.07 ◽

2019 ◽

pp. 62-71

Author(s):

Петр Александрович Фомичев ◽

Игорь Михайлович Сила

Keyword(s):

Service Life ◽

Breaking Load ◽

Strength Characteristics ◽

Test Results ◽

Structural Elements ◽

Term Operation ◽

Lower Confidence ◽

Strength Tests ◽

Normal Law

The technique of processing the test results to the destruction of samples cut from slings and dome fabric after prolonged use or storage of the parachute is described. The normal law of load distribution before failure is adopted.It is proposed to find the minimum breaking load as the lower confidence limit depending on the number of tested samples and a confidence probability of 0.99.The results of strength tests of samples from the parachutes of the landing D-5 series 2 of 1983, the spare Z-5 of 1984, and the rescue S-5K series 2 of 1989 are presented.A total of 301 samples were tested, including 54 samples from slings D-5, 48 samples from slings Z-5 and S-5K, samples from fabrics of domes on the base and weft. Samples from slings were cut out at the edge of the dome, in the middle, at the arc buckles.Fabric samples were cut radially from the top to the edge of the dome. The dependence of the strength characteristics on the location of the samples along the length of the slings or the dome panel has not been established.There are no gross errors in the tests according to the Grubbs criterion.The strength degradation coefficients of the slings and fabrics of the domes are determined as the ratio of the breaking load after long-term operation or storage to the initial values adopted during the design.The proximity of the degradation coefficients of slings and dome fabrics was noted. Based on the set of test results in order to obtain the minimum values of the degradation coefficients, a linear dependence on the life of the parachute is established.This period should be counted from the year the parachute was made.The dependence of the minimum degradation coefficients (maximum degradation) on the service life makes it possible to assess the drop in the strength characteristics of the structural elements with increasing service life. This dependence allows you to predict the maximum allowable landing speed when deciding on the extension of the life of the parachute.

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Research into the lubrication of a rotary lip seal using ferrofluid

Proceedings of the Institution of Mechanical Engineers Part J Journal of Engineering Tribology ◽

10.1177/13506501211053734 ◽

2021 ◽

pp. 135065012110537

Author(s):

Marcin Szczęch

Keyword(s):

Magnetic Fluid ◽

Operating Pressure ◽

Test Results ◽

Friction Zone ◽

Lip Seal ◽

Term Operation ◽

Lip Seals ◽

The Magnetic Field ◽

Lubrication Conditions

The paper presents the results of research into a hybrid seal which is a combination of standard rotary lip seals and a magnetic fluid seal. To maintain the magnetic fluid in the friction zone region, either a specially shaped pole piece was used or the shaft was modified accordingly. The research study concerns the allowable operating pressure and lubrication conditions in short-term and durability tests after which shaft wear was also assessed. Magnetic fluids with different rheological and magnetic properties were considered. The test results showed that the long-term operation of a hybrid seal is possible. The requirements, however, are the appropriate value of the magnetic field and dynamic viscosity of the magnetic fluid.

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Statistical analysis of mechanical test results for samples of pipes from trunk oil pipelines after long-term operation

Pipeline Science and Technology ◽

10.28999/2514-541x-2018-2-2-107-122 ◽

2018 ◽

Vol 2 (2) ◽

pp. 107-122

Author(s):

D. A. Neganov ◽

◽

S. V. Skorodumov ◽

N. Yu. Nikitin ◽

◽

...

Keyword(s):

Statistical Analysis ◽

Mechanical Test ◽

Test Results ◽

Term Operation ◽

Oil Pipelines

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Second Generation Sodium Heat Pipe Receiver for a USAB V-160 Stirling Engine: Evaluation of On-Sun Test Results Using the Proposed IEA Guidelines and Analysis of Heat Pipe Damage

Journal of Solar Energy Engineering ◽

10.1115/1.2888033 ◽

1997 ◽

Vol 119 (4) ◽

pp. 279-285 ◽

Cited By ~ 8

Author(s):

D. Laing ◽

C. Tra¨bing

Keyword(s):

Performance Evaluation ◽

Heat Pipe ◽

Second Generation ◽

International Energy Agency ◽

Test Results ◽

Energy Agency ◽

Term Operation ◽

Sodium Heat Pipe ◽

Absorber Surface

At the DLR a second generation sodium heat pipe receiver for the Schlaich Bergermann und Partner (SBP) 9-kWe dish/Stirling system has been developed and constructed. Long-term operation occurred from Oct. 1992 until Aug. 1993 at the Plataforma Solar de Almeria (PSA) in Spain, accumulating 950 operating hours. The performance of the SBP 9-kWe system with a sodium heat pipe receiver is evaluated according to the guidelines for dish/Stirling performance evaluation by Stine and Powel, as proposed to the International Energy Agency (IEA). Tests were stopped due to a leak in the receiver absorber surface. The analysis of this damage are reported.

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