scholarly journals Improvement of test methods and criteria for evaluation of resistance to flame propagation of long elements of the wiring system

2021 ◽  
Vol 6 (10 (114)) ◽  
pp. 57-68
Author(s):  
Rostyslav Kravchenko ◽  
Pavlo Illiuchenko ◽  
Andrii Onyshchuk ◽  
Oleksandr Zazymko
Keyword(s):  
Correlation Coefficient ◽  
Flame Propagation ◽  
Areal Density ◽  
Test Methods ◽  
Outer Diameter ◽  
Incorrect Decision ◽  
Tissue Paper ◽  
Electrical Wiring ◽  
Criteria For Evaluation ◽  
Wiring System

The test methods for flame propagation of long elements of the electrical wiring system, in particular, cables, cable conduits and ducts, are analyzed, and differences in them are found in the test conditions and criteria for evaluating the resistance to flame propagation. Using a substrate of a wooden board covered with a layer of tissue paper with an areal density of (21±9) g/m2, adopted for testing other elements of the electrical wiring system, a cable was identified that is not resistant to flame propagation. It is proposed to use this substrate for testing the flame propagation of cables instead of a substrate made of a double layer of filter paper with a surface density of (80±15) g/m2. In one of three experiments, a cable that was not resistant to flame propagation was found based on the criterion of the presence of ignition of the substrate located under it. To reduce the risk of making an incorrect decision on compliance, it is proposed that the assessment of long elements of the wiring system be carried out according to the rules established for cable ducts, trays and ladders in EN 50085-1 and IEC 61537. For the AVVG cable with an outer diameter of 10 mm to 60 mm, when it touches the blue flame cone of 1 kW, the correlation coefficient of the dependence of the length of the charred part on the diameter was 0.969. For a distance of 100 mm between the sample and the burner along its axis, a correlation coefficient of 0.985 was obtained. It is proposed to test cables under the second condition recommended in IEC 60695-11-2. For two conduits, flame propagation was revealed when exposed to a 1 kW flame for 120 s and 240 s. However, for these pipelines, flame propagation did not occur under standard conditions of exposure to such a flame for 20 s and 25 s. To identify long elements of the wiring system that are not resistant to flame propagation, it is proposed to test them at a duration of exposure to a flame of 1 kW, established for cables in IEC 60332-1-2

Study on the Test Method of Trace Phosphorous in Drinking Water

2013 ◽  
Vol 316-317 ◽  
pp. 629-631
Author(s):  
Ya Feng Li ◽  
Hui Yang Li ◽  
Xin Li Xie
Keyword(s):  
Drinking Water ◽  
Correlation Coefficient ◽  
Malachite Green ◽  
Test Methods ◽  
Test Method ◽  
Light Path ◽  
Improved Method ◽  
Standard Curve

In order to get an accurate test method of trace phosphorous in drinking water, different test methods of phosphorus were researched. Drew standard curves of these methods, Calculated correlation coefficient of these standard curves for comparison. The result shows that the improved PMA-Malachite Green spectrophotometry was more accurate in the test of trace phosphorus, by using the cuvette with 1cm light path, the correlation coefficient of it's standard curve can reach 0.9995. The improved method is suitable for measuring trace phosphorus in drinking water.

Design and experimental research of stress measurement system for ferromagnetic components based on ACSM method

2021 ◽  
pp. 030932472199810
Author(s):  
Kai Song ◽  
Hongda Sun ◽  
Ximing Cui ◽  
Lipan Zhang
Keyword(s):  
Correlation Coefficient ◽  
Measurement System ◽  
Stress Measurement ◽  
Ferromagnetic Material ◽  
Test Methods ◽  
Uniaxial Tensile ◽  
Signal Acquisition ◽  
Characteristic Quantity ◽  
Uniaxial Tensile Testing ◽  
Safety And Reliability

Stress is one of the important factors that cause fatigue and fracture of ferromagnetic components, and its accurate measurement is of great significance to ensure the safety and reliability of components. Accordingly, a set of alternating magnetic field stress measurement system was designed and developed. The system includes a measurement sensor, DDS signal excitation module, signal conditioning module, signal acquisition, and processing module. The system was used to carry out uniaxial tensile testing of Q235 steel, and the influence of different testing parameters on the testing signal was studied. The research results show that: in the elastic stage, there is a good linear relationship between the real part of the detection signal and the tensile stress. This characteristic quantity can be used to evaluate the stress of ferromagnetic materials; In addition, the correlation coefficient and sensitivity of different detection parameters were compared through linear fitting analysis, and a set of best detection parameters were obtained. Under this parameter, the correlation coefficient reaches 0.991, and the sensitivity is 7.318 mV/kN. The above research provides test methods and techniques for ferromagnetic material stress measurement.

scholarly journals NEW CONCEPTS AND TEST METHODS OF CURVE PROFILE AREA DENSITY IN SURFACE: ESTIMATION OF AREAL DENSITY ON CURVED SPATIAL SURFACE

2011 ◽  
Vol 20 (1) ◽  
pp. 59
Author(s):  
Hong Shen
Keyword(s):  
Test Line ◽  
Areal Density ◽  
Test Methods ◽  
Reference Curve ◽  
Area Density ◽  
Surface Estimation ◽  
New Concepts ◽  
Curve Profile ◽  
Intersection Density ◽  
Profile Area

The concepts of curve profile, curve intercept, curve intercept density, curve profile area density, intersection density in containing intersection (or intersection density relied on intersection reference), curve profile intersection density in surface (or curve intercept intersection density relied on intersection of containing curve), and curve profile area density in surface (AS) were defined. AS expressed the amount of curve profile area of Y phase in the unit containing surface area, S(X). The test methods and formulas were deduced, e.g.: AS=ICI /IC=LCI /BC. In the formula, ICI and IC indicated the intersection numbers of test line with curve intercepts (or profiles in 2D) and with the containing curve respectively. BC denoted the length of containing curve, LCI being the length of curve intercepts. The formula means that AS are equal to the curve intercept density and equal to the curve profile intersection density in surface. Issues about AS application and its correction for shrinking tissues were discussed. Example for testing AS was given.

Sign in / Sign up

Export Citation Format

Share Document