scholarly journals Analysis of Requirements and the Feasible Limit for Error Reduction in Two-Parameter Magnetic Determination of Steels’ Hardness

2020 ◽  
Vol 11 (3) ◽  
pp. 236-244
Author(s):  
S. G. Sandomirski

All measurements of mechanical properties of materials in the magnetic structural analysis are indirect and relationships between the measured parameters are correlated. An important physical parameter of steel is hardness. An increase in the correlation coefficient R and a reduction in the standard deviation (SD) are achieved when controlling the hardness of steels with two-parameter magnetic methods compared to methods that use a single measured parameter. However, the specific conditions and requirements for application of the two-parameter methods remain unclear. The purpose of this article was to analyze conditions and the achievable error reduction limit for two-parameter indirect determination of steels hardness and to compare those with one-parameter methods.In particular, we considered the mean Square Deviation (SD), σF , of indirect calculation of the physical quantity F using two measured parameters x1 and x2 that are correlated with F. It was found that reduction of σF is most pronounced when x1 and x2 are inversely correlated with the maximum modulus |R| of the correlation coefficient R between them. The most significant reduction in σF occurs at similar values of the SDs σ1 and σ2 between the true value of F and the values calculated based on the results of indirect measurements of F usingeach of the parameters x1 and x2 . The Results of the analysis are confirmed by an example of reduction in SD when determining the hardness of carbon steels by measuring their remanent magnetization and coercive force compared to use any one of these parameters.This result can be applied to measurements in non-destructive testing and in related fields of physics and technology. The Results of the analysis allow us to compare different parameters for indirect two-parameter determination of a physical quantity, to select the optimal parameters, and to evaluate the minimum achievable measurement error of a physical quantity by a two-parameter method before performing the measurements.

Author(s):  
Shinji Konosu

The High Pressure Institute of Japan has prescribed the Japanese FFS code, HPIS Z101 Level 1, which can evaluate a crack-like flaw without an extensive knowledge of fracture mechanics. Level 2 is currently being studied and will also be prescribed. In HPIS Z101 Level 2, a two-parameter method (FAD: Failure Assessment Diagram) will be adopted. This paper reveals that FACs dependent on the type of materials should be specified. Kr-Lr relations calculated from experimentally obtained Ramberg-Osgood constants of several steels are compared with the FACs of BS7910 Level 2A & API 579 Level 2, R6 Option 1 and ASME N494-3. It is found that the FAC of ferritic steel in ASME N494-3 is pertinent to carbon steels with a marked yield point plateau while the FAC of BS7910 Level 2A & API 579Level 2 is suitable for ferritic steels other than carbon steels such as 0.5Mo, 2.25Cr-1Mo and 2.25Cr-1Mo-0.25V steels. Further, cut-off values dependent on the strength of the material and the plasticity interaction factors for the FAC of carbon steels are proposed.


Author(s):  
Marek Berezowski

AbstractThe work relates to development and presentation a two-parameter continuation method for determining catastrophic sets of stationary states of a tubular chemical reactor with mass recycle. The catastrophic set is a set of extreme points occurring in the bifurcation diagrams of the reactor. There are many large IT systems that use the parametric continuation method. The most popular is AUTO’97. However, its use is sometimes not convenient. The method developed in this work allows to eliminate the necessity to use huge IT systems from the calculations. Unlike these systems, it can be inserted into the program as a short subroutine. In addition, this method eliminates time-consuming iterations from the calculations.


2013 ◽  
Vol 788 ◽  
pp. 23-26
Author(s):  
Gui Qing Wen ◽  
Ai Hui Liang

In HCl medium and in the presence of CuSO4, Na3AsO4 can be reduced by NaH2PO2 to form As nanoparticles (AsNs) which exhibited a strong resonance Rayleigh scattering (RRS) peak at 370 nm. Under the chosen conditions, the increased intensity at 370 nm was linear to As5+ concentration in the range of 0.48-38.0×10-6 mol/L, with a regression equation of ΔI370nm = 82.3 CAs + 33.9, a correlation coefficient of 0.9878 and a detection limit of 2.0×10-7 mol/L As5+. The proposed method was applied to detect As5+ concentration in waste water, with simplicity, rapidity and accuracy. Thus, a novel RRS spectral method was established to determine As5+.


1968 ◽  
Vol 17 (2) ◽  
pp. 381-384 ◽  
Author(s):  
L. Gedda ◽  
D. Casa ◽  
G. Brenci

SummaryDosage of the hematic level of ATP has been afforded in 20 (7 MZ and 13 DZ) twin pairs aged 4-6 years. The intrapair correlation coefficient has been calculated and resulted to be significantly higher in MZ than DZ twin pairs. The hereditary “quantum” in the determination of the hematic level of ATP was also estimated and resulted to be of about two thirds.


2012 ◽  
Vol 524-527 ◽  
pp. 598-603
Author(s):  
Nian Jie Ma ◽  
Zhi Qiang Zhao ◽  
Hua Zhao ◽  
Li Shuai Jiang

In order to solve the serious damage and repeat revision problem of high stress soft rock roadway in deep -950 level of Tangshan coal mine, based on the theory of the maximum stress level, together with the actual measurement of geostress and the laboratory mechanical parameters of rock-core and computer numerical simulation, the high strength combined support technology and supporting parameters are determined and the engineering test has been done. The engineering test results show that the parameter determination of high strength combined support technology, which based on the actual measurement of geostress, can effective solve the support issue of high stress soft rock roadway and provide useful experience for similar engineering problems.


1914 ◽  
Vol 8 (1) ◽  
pp. 25-49
Author(s):  
Alfred L. P. Dennis

War has marked the year 1913; and charges and countercharges as to alleged atrocities by belligerents have been rife. Treaties were drawn to be promptly torn up; and solemn declarations of intention and policy often proved futile. The existence of internal disorder and the outbreak of domestic revolutions in several countries have also exerted disturbing influences on international relations. The result was economic loss and diplomatic tension even well beyond the field of military operations. And these conditions have led to renewed activity in the struggle for concessions and investment in renascent communities. Racial and religious sentiments have also aroused bitter feeling; while political leaders in several countries compel renewed consideration of the weight of individuals in the determination of the world's affairs.In large part the problems of 1913 were historic; but in part they were affected by apparently impending changes which we cannot as yet define. Thus the influence of socialism and of various forms of radical thought on international relations is a factor. The adoption of oil as a naval fuel, the opening of the Panama Canal, the plans for administrative reorganization of Turkey, and its capitalistic development, the renewed debate as to the Monroe doctrine, and the problem of China are all matters whose future significance scarcely concern us here; but their influence in the past year has been unquestionably great. We cannot estimate as yet the true value of many recommendations touching various fields of international coöperation; and the value of delay in international action still remains in dispute. So on the whole the year 1913 has apparently been the year of the cynic.


2013 ◽  
Vol 49 (5) ◽  
pp. 2097-2105 ◽  
Author(s):  
Kaushik Mukherjee ◽  
K. Lakshmi Varaha Iyer ◽  
Xiaomin Lu ◽  
Narayan C. Kar

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