Control of Defects on the Parameters of the Electromagnetic Response under Pulsed Mechanical Excitation of the Sample

2015 ◽  
Vol 1085 ◽  
pp. 316-318
Author(s):  
Petr Khorsov ◽  
Nikolay Khorsov ◽  
Vladimir Surzhikov
Keyword(s):  
Acoustic Emission ◽  
Dielectric Material ◽  
Electromagnetic Emission ◽  
Excitation Pulse ◽  
Electromagnetic Response ◽  
Electromagnetic Signal ◽  
Random Component ◽  
Dielectric Sample ◽  
Random Components ◽  
Stepwise Loading

The paper assessed the possibility of using acoustic emission from the dielectric sample during stepwise loading. The electromagnetic signal from the sample was detected by using an apparatus of mechanical repeatedly pulsed excitation of the sample at each stage of loading. It was found that the response consists of a deterministic component (due to the excitation pulse) and random components noise and acoustic emission. It were allocated random components, calculated their standard deviations. The influence of the electromagnetic emission on standard deviation of the random component of response under step load on the specimen was evaluated. It has been shown that the component of the electromagnetic emission can be an informative parameter to evaluate defectiveness of the object of a dielectric material under load.

A Proposed Model for Stochastic Vibration Analysis of Gear Transmission Systems

1996 ◽  
Author(s):  
Y. Wang ◽  
W. Zhang
Keyword(s):  
Vibration Analysis ◽  
Linear Time ◽  
Simulation System ◽  
Gear Transmission ◽  
Random Component ◽  
Transmission Systems ◽  
Transmission Errors ◽  
Proposed Model ◽  
Rotational Vibration ◽  
Random Components

Abstract A new mathematical model is presented for analyzing the vibration of gear transmission systems with consideration of the influence of the time-variant stiffness, loads, gear transmission errors. The gear transmission system is modeled as a non-linear, time-correlated and stationary stochastic system. The transmission errors of gears are decomposed into harmonic and random components in terms of the different characteristics of their spectrums. The random component is simulated by a second order Markov process. A simulation system for vibration analysis of gear transmission systems is then developed, based on this new model. The input to this system is a Guassian white noise process and harmonic errors, and the output is the rotational vibration acceleration of gears. Some experiments are conducted to verify the proposed model. By comparing the results generated from the simulation system with those from the experiments, the proposed model is found to reach a fairly good accuracy, and thus the model is useful in designing gear transmission systems with the objective to reduce the vibration and noise of the systems in operation.

scholarly journals Mutation effect of acoustic and electromagnetic emissions of hard rock impact failure

2019 ◽  
Vol 15 (1) ◽  
pp. 155014771882447
Author(s):  
Yang Liu ◽  
Cai-Ping Lu ◽  
Heng Zhang
Keyword(s):  
Acoustic Emission ◽  
Hard Rock ◽  
Acoustic Emissions ◽  
Electromagnetic Emission ◽  
Rock Fracturing ◽  
Impact Failure ◽  
Hard Roof ◽  
Micro Cracks ◽  
Roof Fall ◽  
Microseismic Event

To reveal acoustic emission and electromagnetic emission effects during hard rock impact failure is a crucial issue for monitoring and warning rockburst risk induced by hard roof fracture and fall. The presented research focuses on acoustic emission and electromagnetic emission and microseismic effects detected during laboratory tests and by in situ multi-parameter observations, and the field observations agreed satisfactorily with the experimental evidences. The following main conclusions were drawn: (1) the stress level, frequency of micro-cracks, and impact failure regularity of hard rocks can be revealed with electromagnetic emission and acoustic emission/microseismic parameters, respectively; (2) acoustic emission/microseismic event counts can directly reveal the cracks change in rocks, and the initiation, propagation, and coalescence of micro-cracks can be presented as first increase, followed by decrease in acoustic emission/microseismic event counts; (3) in most cases, only when stress suddenly decreases or the rock final collapses, acoustic emissions show obviously abnormal; and (4) acoustic emission/microseismic can be more effectively applied to warn rockburst danger. The above conclusions may shed light on the effective monitoring and warning methods of rockburst triggered by hard roof fall, and events contribute to some interpretations to originally transient precursors of hard rock fracturing.

Possibility of Evaluating a Depth of Defects as a Hole in a Composite Dielectric Sample by the Parameters of Electric Response to Pulse Mechanical Excitation

2018 ◽  
Vol 781 ◽  
pp. 155-158 ◽  
Author(s):  
Petr Khorsov ◽  
Anatoly Surzhikov ◽  
Vladimir Surzhikov ◽  
Roman Laas
Keyword(s):  
Mathematical Model ◽  
Electromagnetic Response ◽  
Electric Response ◽  
One Dimensional ◽  
Response Parameter ◽  
Dielectric Sample ◽  
Receiver System ◽  
Mechanoelectrical Transformations ◽  
Spurious Component ◽  
The One

The applicability of the method mechanoelectrical transformations (MET) to determine the depth of the macrodefects location in the sample on parameters of the electromagnetic response is evaluated. As the response parameter it was used the phase characteristic of the signal analytical representation.On the one-dimensional mathematical model it was shown the possibility to detect phase response changes when reflected from defect acoustic wave is mixed with the signal spurious component generated by a distributed MET sources. Experimental verification of mathematical model on a sample of concrete was conducted. It has been shown that the sensitivity of the method MET to evaluation of the macrodefect locate depth depends on the wavelength of the excitation pulse and the area of the macrodefect border closest to the emitter-receiver system.

scholarly journals Эмиссионная активность при ударном разрушении керамик A-=SUB=-2-=/SUB=-B-=SUB=-6-=/SUB=-

2018 ◽  
Vol 44 (15) ◽  
pp. 58
Author(s):  
И.П Щербаков ◽  
А.A. Дунаев ◽  
А.Е. Чмель
Keyword(s):  
Time Series ◽  
Acoustic Emission ◽  
Crystallite Size ◽  
Time Resolution ◽  
Impact Loading ◽  
Electromagnetic Emission ◽  
Mechanical Action ◽  
Parallel Time ◽  
Emission Activity

AbstractIn this paper, we present results of a study of the generation of electromagnetic emission during impact loading of ZnS and ZnSe ceramics prepared by various techniques. The choice of the type of mechanical action is associated with the typical applications of these ceramics. Separate contributions to emission activity from the dislocations movement and the microcracks development depending on the crystallite size in the ceramics are shown. The electromagnetic emission is compared with parallel time series of pulses of mechanoluminescence and acoustic emission. In all three cases, emission activity was recorded with a time resolution of 10 ns.

On the Interpretation of the Acoustic Emission Signals

1976 ◽  
Vol 98 (3) ◽  
pp. 199-207 ◽  
Author(s):  
A. C. Lucia ◽  
G. Redondi
Keyword(s):  
Acoustic Emission ◽  
Statistical Analysis ◽  
Tensile Tests ◽  
Random Component ◽  
Stationary Signals ◽  
Interpretation Problem

The A.E. signals are of nonstationary random type, the nonstationarity being connected with the evolution of the source, whose characterization is here pursued by the development of methodologies of statistical analysis of non stationary signals. The A.E. signal is hypothesized to be constituted by a combination of a stationary random component and a deterministic one, whose behavior represents the evolution of the source. The determination of this latter component is carried out for signals from tensile tests on C.T. specimens. A second approach to the signal interpretation problem is also presented. It is based on the representation of the A.E. signal as random pulses of varying duration and amplitude.

scholarly journals Research on Acoustic Emission and Electromagnetic Emission Characteristics of Rock Fragmentation at Different Loading Rates

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Fujun Zhao ◽  
Yu Li ◽  
Zhouyuan Ye ◽  
Yong Fan ◽  
Siping Zhang ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Loading Rate ◽  
Electromagnetic Emission ◽  
Rock Fragmentation ◽  
Loading Rates ◽  
Peak Intensity ◽  
Wave Forms ◽  
Show Jumping ◽  
Peak Count ◽  
Good Agreement

The relationships among the generation of acoustic emission, electromagnetic emission, and the fracture stress of rock grain are investigated, which are based on the mechanism of acoustic emission and electromagnetic emission produced in the process of indenting rock. Based on the relationships, the influence of loading rate on the characteristics of acoustic emission and electromagnetic emission of rock fragmentation is further discussed. Experiment on rock braking was carried out with three loading rates of 0.001 mm/s, 0.01 mm/s, and 0.1 mm/s. The results show that the phenomenon of acoustic emission and electromagnetic emission is produced during the process of loading and breaking rock. The wave forms of the two signals and the curve of the cutter indenting load show jumping characteristics. Both curves have good agreement with each other. With the increase of loading rate, the acoustic emission and electromagnetic emission signals are enhanced. Through analysis, it is found that the peak count rate, the energy rate of acoustic emission, the peak intensity, the number of pulses of the electromagnetic emission, and the loading rate have a positive correlation with each other. The experimental results agree with the theoretical analysis. The proposed studies can lead to an in-depth understanding of the rock fragmentation mechanism and help to prevent rock dynamic disasters.

Mass and composition of the fat-free tissues of patients with weight-loss

1985 ◽  
Vol 68 (4) ◽  
pp. 455-462 ◽  
Author(s):  
L. Burkinshaw ◽  
D. B. Morgan
Keyword(s):  
Factor Analysis ◽  
Standard Error ◽  
Healthy Subjects ◽  
The Body ◽  
Fat Free Mass ◽  
Random Component ◽  
Total Body Potassium ◽  
Random Components ◽  
Total Body ◽  
True Values

1. An estimate of the mass of fat-free tissue in the body can be calculated from body weight and skinfold thickness; this estimate is called the ‘fat-free mass'. Total body potassium and nitrogen are alternative estimates. Factor analysis of data for healthy subjects has defined relationships between the true values of these three quantities and estimated the random component of the variance of each, i.e. the component independent of variations in the mass of fat-free tissue. The results indicated that all three were reliable measures of the mass of fat-free tissue. However, it is not known whether these findings are valid for patients who have lost weight. 2. We have measured the same three quantities in 104 wasted patients with heart disease or disorders of the gastrointestinal tract. The patients’ mean values were significantly less than corresponding values for healthy volunteers. The patients had a mean ratio of total body nitrogen to fat-free mass similar to that of healthy subjects, but lower mean ratios of potassium to fat-free mass and nitrogen. These findings suggest that the potassium content of the patients’ fat-free tissues was abnormally low. 3. Factor analysis of the patients’ data gave relationships between the true values of the three quantities similar to those for healthy subjects; however, total body potassium was 100-300 mmol lower in patients than in healthy subjects with the same fat-free mass or total body nitrogen. 4. Factor analysis also showed that the random components of variance of fat-free mass and total body nitrogen were similar to those in healthy subjects. Therefore, in the patients as in healthy subjects, fat-free mass was as valid a measure of fat-free tissue as the more complex measurement of total body nitrogen. The random component of total body potassium was twice as big as in healthy subjects; however, it formed no greater a proportion of total variance than did the random components of the other two quantities. 5. Total body nitrogen, and hence body protein, could be estimated from measured fat-free mass with a standard error of approximately 136 g (compared with 139 g for healthy individuals), and from total body potassium with a standard error of 129 g (compared with 91 g in healthy subjects).

scholarly journals Modeling random and non-random decision uncertainty in ratings data: a fuzzy beta model

2021 ◽  
Author(s):  
Antonio Calcagnì ◽  
Luigi Lombardi
Keyword(s):  
Statistical Approach ◽  
Expectation Maximization Algorithm ◽  
Main Idea ◽  
Social Contexts ◽  
Random Component ◽  
Decision Uncertainty ◽  
Random Components ◽  
Variable Dispersion ◽  
Data Subject ◽  
Do So

AbstractModeling human ratings data subject to raters’ decision uncertainty is an attractive problem in applied statistics. In view of the complex interplay between emotion and decision making in rating processes, final raters’ choices seldom reflect the true underlying raters’ responses. Rather, they are imprecisely observed in the sense that they are subject to a non-random component of uncertainty, namely the decision uncertainty. The purpose of this article is to illustrate a statistical approach to analyse ratings data which integrates both random and non-random components of the rating process. In particular, beta fuzzy numbers are used to model raters’ non-random decision uncertainty and a variable dispersion beta linear model is instead adopted to model the random counterpart of rating responses. The main idea is to quantify characteristics of latent and non-fuzzy rating responses by means of random observations subject to fuzziness. To do so, a fuzzy version of the Expectation–Maximization algorithm is adopted to both estimate model’s parameters and compute their standard errors. Finally, the characteristics of the proposed fuzzy beta model are investigated by means of a simulation study as well as two case studies from behavioral and social contexts.

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