Metal Magnetic Memory Testing Technique for Typical Defects in Pressure Vessels and Pipelines

2015 ◽  
Author(s):  
Weihe Guan ◽  
Pengju Guo ◽  
Chen Xuedong
Keyword(s):  
High Efficiency ◽  
Low Cost ◽  
Orientation Angle ◽  
High Sensitivity ◽  
Pressure Vessels ◽  
Magnetic Memory ◽  
Metal Magnetic Memory ◽  
Time Saving ◽  
Hydrogen Induced Cracking ◽  
Memory Signals

Metal magnetic memory technique has been extensively applied in different fields due to its unique advantages of time-saving, low cost, and high efficiency. However, very limited research has been carried out on studying the characteristics of metal magnetic memory signals of different defects except crack, and also the effect of orientation angle between testing direction and defect on magnetic memory signals. To promote study in this area, the magnetic memory signals of typical defects (such as crack, slag inclusion) are investigated as well as hydrogen-induced cracking. In addition, the characteristics of magnetic memory signals when measured with different angle between testing direction and defects were obtained. The results indicate that the metal magnetic memory technique is a promising method to detect typical defects of welding and also hydrogen-induced cracking. Moreover, the technique has high sensitivity on defects no matter the angle between testing direction and defect. However, further research is needed because it can only find the possible location of defects but cannot quantitatively describe the defect.

Effect of tensile stress on metal magnetic memory signals during on-line measurement in ferromagnetic steel

2021 ◽  
Vol 117 ◽  
pp. 102378
Author(s):  
Huipeng Wang ◽  
Lihong Dong ◽  
Haidou Wang ◽  
Guozheng Ma ◽  
Binshi Xu ◽  
...  
Keyword(s):  
Tensile Stress ◽  
Magnetic Memory ◽  
Metal Magnetic Memory ◽  
Line Measurement ◽  
On Line ◽  
Memory Signals ◽  
Ferromagnetic Steel

scholarly journals Marine Toxins Detection by Biosensors Based on Aptamers

Toxins ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 1 ◽  
Author(s):  
Wei Ye ◽  
Taomei Liu ◽  
Weimin Zhang ◽  
Muzi Zhu ◽  
Zhaoming Liu ◽  
...  
Keyword(s):  
Detection Limit ◽  
Sensitivity And Specificity ◽  
High Efficiency ◽  
Rapid Development ◽  
High Sensitivity ◽  
Detection Methods ◽  
Marine Toxins ◽  
Time Saving ◽  
Low Detection Limit ◽  
The Future

Marine toxins cause great harm to human health through seafood, therefore, it is urgent to exploit new marine toxins detection methods with the merits of high sensitivity and specificity, low detection limit, convenience, and high efficiency. Aptasensors have emerged to replace classical detection methods for marine toxins detection. The rapid development of molecular biological approaches, sequencing technology, material science, electronics and chemical science boost the preparation and application of aptasensors. Taken together, the aptamer-based biosensors would be the best candidate for detection of the marine toxins with the merits of high sensitivity and specificity, convenience, time-saving, relatively low cost, extremely low detection limit, and high throughput, which have reduced the detection limit of marine toxins from nM to fM. This article reviews the detection of marine toxins by aptamer-based biosensors, as well as the selection approach for the systematic evolution of ligands by exponential enrichment (SELEX), the aptamer sequences. Moreover, the newest aptasensors and the future prospective are also discussed, which would provide thereotical basis for the future development of marine toxins detection by aptasensors.

scholarly journals New traps for the capture of Aedes aegypti (Linnaeus) and Aedes albopictus (Skuse) (Diptera: Culicidae) eggs and adults

2020 ◽  
Author(s):  
Karina Rossi da Silva ◽  
William Ribeiro da Silva ◽  
Bianca Piraccini Silva ◽  
Adriano Nobre Arcos ◽  
Francisco A. da Silva Ferreira ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Aedes Albopictus ◽  
High Efficiency ◽  
Low Cost ◽  
High Sensitivity ◽  
Ease Of Use ◽  
Monitoring And Control ◽  
Density Index ◽  
Egg Density ◽  
And Control

AbstractThe control of arboviruses carried by Aedes aegypti (Linnaeus) and Aedes albopictus (Skuse) can be performed with tools that monitor and reduce the circulation of these vectors. Therefore, the efficiency of four types of traps in capturing A. aegypti and A. albopictus eggs and adults, with the biological product Vectobac WG®, was evaluated in the field. For this, 20 traps were installed in two locations, which were in the South (Londrina, Paraná) and North (Manaus, Amazonas) Regions of Brazil, from March to April 2017 and January to February 2018, respectively. The UELtrap-E and UELtrap-EA traps captured A. aegypti and A. albopictus eggs: 1703/1866 eggs in Londrina, and 10268/2149 eggs in Manaus, respectively, and presented high ovitraps positivity index (OPI) values (averages: 100%/100% in Londrina, and 100%/96% in Manaus, respectively); and high egg density index (EDI) values (averages: 68/75 in Londrina, and 411/89 in Manaus, respectively), so they had statistically superior efficiency to that of the CRtrap-E and CRtrap-EA traps in both regions, that captured less eggs and adults: 96/69 eggs in Londrina, and 1091/510 eggs in Manaus, respectively. Also presented lower OPI values (averages: 28%/4% in Londrina, and 88%/60% in Manaus, respectively); and lower EDI values (averages: 10.5/9 in Londrina, and 47/30 in Manaus, respectively). The capture ratios of Aedes adults in the UELtrap-EA and CRtrap-EA traps in Londrina and Manaus were 53.3%/29.5% and 0%/9.8%, respectively. UELtrap-E and UELtrap-EA can be adopted as efficient tools for Aedes monitoring due to their high sensitivity, low cost and ease of use.Author summaryAedes aegypti and Aedes albopictus are species of mosquitoes responsible for the transmission of several arboviruses that cause infections worldwide. However, there are still no effective and safe vaccines or medications to prevent or treat arboviruses transmitted by these vectors, except for yellow fever. Moreover, current methodologies for monitoring and controlling A. aegypti and A. albopictus are not fully effective, as evidenced by the increasing cases of the arbovirus transmitted by these mosquitoes or have incompatible costs with the socioeconomic conditions of a large number of people. Thus, the traps tested in this study can be used as more effective and economical tools for monitoring and controlling A. aegypti and A. albopictus, since they are made with low cost material and they showed high efficiency in the capture of eggs, evidenced by the high values of ovitraps positive index and eggs density index, besides that one of the models captured Aedes spp. adults in both regions where they were tested. Therefore, the traps have potential for reducing Aedes spp. eggs and adults in the environment and sensibility for determining the local infestation index, which can be reconciled with official government strategies for more accurate vector monitoring and control actions.

scholarly journals The Quantitative Prediction of Pipeline Cracks Using Metal Magnetic Memory Based on a Regression Model

2014 ◽  
Vol 8 (1) ◽  
pp. 1-8
Author(s):  
Lihong Gong ◽  
Zhuxin Li ◽  
Zhiqiang Song
Keyword(s):  
Regression Model ◽  
High Efficiency ◽  
Quantitative Description ◽  
Surface Preparation ◽  
Quantitative Prediction ◽  
Coefficient Of Determination ◽  
Magnetic Memory ◽  
Metal Magnetic Memory ◽  
Early Failures ◽  
As Stress

The technique of metal magnetic memory (MMM) has great advantages in detecting early failures such as stress concentration and fatigue damage of ferromagnetic components, which has been widely applied due to its high efficiency, low requirements for surface preparation and ease of operation. However, research into the quantitative description of defect characteristics is still far from adequate. To promote relative study in this area, in this paper, a regression model is employed to analyze the sizes of surface cracks in pipelines. Three nonlinear functions are obtained to predict the length, width and depth of cracks respectively based on a regression model. Length prediction is convenient and accurate, with the average coefficient of determination of training samples up to 0.994 and that of testing samples 0.962. Moreover, as the width and depth are small (less than 2 mm), the accuracy of size prediction is very high. The obtained functions provide a useful method of predicting the crack sizes of pipelines according to MMM signals.

scholarly journals Diagnosis Model of Pipeline Cracks According to Metal Magnetic Memory Signals Based on Adaptive Genetic Algorithm and Support Vector Machine

2015 ◽  
Vol 9 (1) ◽  
pp. 1076-1080 ◽  
Author(s):  
Lihong Gong ◽  
Zhuxin Li ◽  
Zhen Zhang
Keyword(s):  
Support Vector Machine ◽  
Kernel Functions ◽  
Support Vector ◽  
Adaptive Genetic Algorithm ◽  
Magnetic Memory ◽  
Metal Magnetic Memory ◽  
Stress Concentrations ◽  
Rbf Kernel ◽  
Diagnosis Model ◽  
Memory Signals

Metal magnetic memory (MMM) signals can reflect stress concentration and cracks on the surface of ferromagnetic components, but the traditional criteria used to distinguish the locations of these stress concentrations and cracks are not sufficiently accurate. In this study, 22 indices were extracted from the original MMM signals, and the diagnosis results of 4 kernel functions of support vector machine (SVM) were compared. Of these 4, the radial basis function (RBF) kernel performed the best in the simulations, with a diagnostic accuracy of 94.03%. Using the principles of adaptive genetic algorithms (AGA), a combined AGA-SVM diagnosis model was created, resulting in an improvement in accuracy to 95.52%, using the same training and test sets as those used in the simulation of SVM with an RBF kernel. The results show that AGA-SVM can accurately distinguish stress concentrations and cracks from normal points, enabling them to be located more accurately.

scholarly journals WHEEZE RECOGNITION BASED ON 2D BILATERAL FILTERING OF SPECTROGRAM

2006 ◽  
Vol 18 (03) ◽  
pp. 128-137 ◽  
Author(s):  
BOR-SHING LIN ◽  
BOR-SHYH LIN ◽  
HUEY-DONG WU ◽  
FOK-CHING CHONG ◽  
SAO-JIE CHEN
Keyword(s):  
High Performance ◽  
Analog Circuit ◽  
High Efficiency ◽  
Low Cost ◽  
High Sensitivity ◽  
Bilateral Filter ◽  
Recognition System ◽  
Detection Algorithm ◽  
Respiratory Sounds ◽  
Edge Preserving

This paper describes the design of a low-cost and high performance wheeze recognition system. First, respiratory sounds are captured, amplified and filtered by an analog circuit; then digitized through a PC soundcard, and recorded in accordance with the Computerized Respiratory Sound Analysis (CORSA) standards. Since the proposed wheeze detection algorithm is based on the spectrogram processing of respiratory sounds, spectrograms generated from recorded sounds have to pass through a 2D bilateral filter for edge-preserving smoothing. Finally, the processed spectra go through an edge detection procedure to recognize wheeze sounds.Experiment results show a high sensitivity of 0.967 and a specificity of 0.909 in qualitative analysis of wheeze recognition. Due to its high efficiency, great performance and easy-to-implement features, this wheeze recognition system could be of interest in the clinical monitoring of asthma patients and the study of physiological mechanisms in the respiratory airways.

Variation regularity of metal magnetic memory signals with inspecting time-interval and location

2007 ◽  
Vol 14 (3) ◽  
pp. 319-323 ◽  
Author(s):  
Chun-yan Yan ◽  
Wu-shen Li ◽  
Xin-jie Di ◽  
Zhen-kui Xue ◽  
Shi-wu Bai ◽  
...  
Keyword(s):  
Time Interval ◽  
Magnetic Memory ◽  
Metal Magnetic Memory ◽  
Memory Signals
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