scholarly journals Weld Flaw Detection Based on Likelihood Estimation and Wavelet Transform

2019 ◽  
Vol 8 (6S3) ◽  
pp. 1734-1738
Keyword(s):  
Visual Inspection ◽  
Measurement Techniques ◽  
Flaw Detection ◽  
Welding Process ◽  
Likelihood Estimation ◽  
Actual Application ◽  
Welded Structure ◽  
Relevant Domain ◽  
Huge Investment

The metals are fused at high temperature using various welding methods to form mechanical structures. The structural stability is achieved in metals by the proper welding process utilized. The failure may result in disaster and huge investment has to be incurred towards building the flawless structures. It is always preferred to check the quality of the weld before the final welded structure is used for its actual application. Though visual inspections could solve problems tentatively valid for low production rates, there are scenarios where visual inspection fails and needs high end methods to analyze the quality of welded joints. Several measurement techniques have evolved and help the user community. The objective of this paper is reviewing such earlier methods in the relevant domain of research and tabulates the various merits and demerits so as to find a method to overcome earlier drawbacks. Further, edge detection is done based on adaptive thresholding method to find the weld flaws

scholarly journals FCAW vertical welding of “V” butt plate in AC UHV transmission line construction

2018 ◽  
Vol 175 ◽  
pp. 03001
Author(s):  
Han Yang ◽  
Chen Kerui ◽  
Li Yang ◽  
Qu Bao
Keyword(s):  
Transmission Line ◽  
Large Scale ◽  
Optimal Allocation ◽  
Welding Process ◽  
Steel Structure ◽  
Solid Core ◽  
Flux Cored Arc Welding ◽  
Welded Structure ◽  
Wide Range

In twenty-first Century, China vigorously promoted the research and construction of AC and DC transmission technology in order to ensure the optimal allocation of energy resources in a large scale[1]. In the construction of AC UHV transmission line, the welding quality of tower and stiffening plate as the load bearing tower and the tension of the welded structure plays an important role in the overall quality of the steel structure. In the past, the welding process of semi automatic carbon dioxide solid core welding wire often has the characteristics of weld spatter not easy to clean up and low efficiency of welding. The semi-automatic CO2 flux cored arc welding, has the characteristics of current and voltage to adapt to a wide range, melting speed, has important significance for improving the process, this paper describes the technology in practical engineering applications, and developed the basic strategy of training for grid steel structure welding technicians. This paper also lists both V groove plate butt FCAW welding typical welding project, hope this welding process will continue to spread.

Increasing the Quality of Welded Joints of Al-Si 6082 Alloys by Introducing Forced Vibrations

2017 ◽  
Vol 907 ◽  
pp. 231-237
Author(s):  
Mihai Alexandru Bodeanu ◽  
Teodor Machedon-Pisu
Keyword(s):  
Longitudinal Vibration ◽  
Welding Process ◽  
Solidification Process ◽  
Forced Vibrations ◽  
Major Influence ◽  
Material Structure ◽  
Welding Equipment ◽  
Welded Structure ◽  
Surface Welding

The solidification process of aluminum alloys welded area has a major influence on the quality of the joining material. Based on this fact, the introduction of forced vibrations during welding aims to prevent the formation of increase tensions inside the welded structure and diminish the presence of pinholes or pores as a result of material contraction of alloys containing metals with a different melting point / solidification point.To avoid this happening it is essential to know and control how the melted material is evolving during the solidification. This step requires that the Al-Si alloy to be welded on a surface with longitudinal vibration composed of a platform whose support can be controlled depending on the required frequency and un M.I.G welding equipment with mechanized welding torch setup to weld, the test peace, above the platform surface. Welding in a mechanical forced vibration environment, results in the formation of a more uniform and finer grain size microstructure with a more advanced diffusion in the affected zone. The diffusion process occurs faster resulting in decreased structural tensions. The presence of voids and pores inside the material structure is inferior for the oscillating welding process in comparison with the classic solution.

Review of Welding Residual Stress Stiffening Effect on Vibrational Characteristics of Structures Using Damage Approach and Vibratory Stress Relief Implementation

2017 ◽  
Author(s):  
AmirHossein MajidiRad ◽  
Yimesker Yihun
Keyword(s):  
Residual Stress ◽  
Modal Analysis ◽  
Structural Integrity ◽  
Material Selection ◽  
Welding Process ◽  
Stress Relief ◽  
Welding Residual Stress ◽  
Welded Structure ◽  
Welding Procedure

There is a huge amount of research and study on the quality, parameter manipulation, material selection etc. of welding to develop optimized results for specific applications. To have a profound understanding of the process, and to investigate and verify various parameters which affect the quality of the welding process, experts use analytical, numerical and experimental methods. The major concern regarding the welding procedure is welding defect, which can affect the integrity of the welded structure. Various nondestructive structural health monitoring methods and modal analysis techniques have been employed to study and improve the strength and quality of the welded structure. Modal analysis is one of the most accurate and commercial techniques to track down the damage within the structures. It uses natural frequency, damping factors and modal shapes to observe the structural and material defects in details. There have been noticeable developments in this area and lots of studies have been conducted applying this technique to put welding procedure under rigorous scrutiny to improve its efficiency. While modal analysis is a tool to identify structural integrity of the components, vibration can affect the nature of the metal and change the mechanical properties in some cases. Mechanical vibration and Ultrasonic as low and high frequency oscillations respectively, are able to change the microstructure of the structures so that dislocations move, hence the stress trapped within will redistribute. This redistribution can lead to residual stress reduction up to a level. In this review paper, all remarks above are considered, defined and accurately studied through various cases in order to address different application of vibratory stress relief and recent achievement in this field.

Counterfeit Parts Recognition and Detection for Failure Analysts

2010 ◽  
Author(s):  
Katherine V. Whittington
Keyword(s):  
Thermal Cycle ◽  
Visual Inspection ◽  
Acoustic Microscopy ◽  
Scanning Acoustic Microscopy ◽  
3D Measurement ◽  
X Ray ◽  
Wide Range ◽  
Electronic Parts ◽  
Testing Awareness

Abstract The electronics supply chain is being increasingly infiltrated by non-authentic, counterfeit electronic parts, whose use poses a great risk to the integrity and quality of critical hardware. There is a wide range of counterfeit parts such as leads and body molds. The failure analyst has many tools that can be used to investigate counterfeit parts. The key is to follow an investigative path that makes sense for each scenario. External visual inspection is called for whenever the source of supply is questionable. Other methods include use of solvents, 3D measurement, X-ray fluorescence, C-mode scanning acoustic microscopy, thermal cycle testing, burn-in technique, and electrical testing. Awareness, vigilance, and effective investigations are the best defense against the threat of counterfeit parts.

Multifactor mathematical model of criticality of welding process of products from aluminum- magnesium alloys

2020 ◽  
pp. 12-18
Author(s):  
F.A. Urazbahtin ◽  
A.YU. Urazbahtina
Keyword(s):  
Mathematical Model ◽  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Welding Process ◽  
Welding Equipment ◽  
Equipment Operation ◽  
Aluminum Magnesium Alloys ◽  
Aluminum Magnesium Alloy ◽  
Welding Materials

A multifactor mathematical model of the welding process of products from aluminum-magnesium alloys, consisting of 71 indicators that assess the quality of the weld, the welding process, costs, equipment operation and quality of the welded material. The model can be used to control and optimize the welding process of products from aluminum-magnesium alloys. Keywords welding, products, aluminum-magnesium alloy, indicators, process parameters, welding equipment, welding materials, electrode sharpening, lining [email protected]

scholarly journals Identifying Stabilising Effects on Survey Based Life Satisfaction Using Quasi-maximum Likelihood Estimation

2021 ◽  
Author(s):  
Johannes Klement
Keyword(s):  
Life Satisfaction ◽  
Maximum Likelihood ◽  
Maximum Likelihood Estimation ◽  
Negative Binomial ◽  
Measurement Instrument ◽  
Likelihood Estimation ◽  
Satisfaction Scale ◽  
Quasi Maximum Likelihood ◽  
The Stability

AbstractTo which extent do happiness correlates contribute to the stability of life satisfaction? Which method is appropriate to provide a conclusive answer to this question? Based on life satisfaction data of the German SOEP, we show that by Negative Binomial quasi-maximum likelihood estimation statements can be made as to how far correlates of happiness contribute to the stabilisation of life satisfaction. The results show that happiness correlates which are generally associated with a positive change in life satisfaction, also stabilise life satisfaction and destabilise dissatisfaction with life. In such as they lower the probability of leaving positive states of life satisfaction and increase the probability of leaving dissatisfied states. This in particular applies to regular exercise, volunteering and living in a marriage. We further conclude that both patterns in response behaviour and the quality of the measurement instrument, the life satisfaction scale, have a significant effect on the variation and stability of reported life satisfaction.

scholarly journals Analysis of Noise and Velocity in GNSS EPN-Repro 2 Time Series

2021 ◽  
Vol 13 (14) ◽  
pp. 2783
Author(s):  
Sorin Nistor ◽  
Norbert-Szabolcs Suba ◽  
Kamil Maciuk ◽  
Jacek Kudrys ◽  
Eduard Ilie Nastase ◽  
...  
Keyword(s):  
Time Series ◽  
Visual Inspection ◽  
Flicker Noise ◽  
Vertical Component ◽  
Likelihood Estimation ◽  
Noise Model ◽  
Noise Amplitude ◽  
Allan Deviation ◽  
Power Spectral ◽  
Position Time Series

This study evaluates the EUREF Permanent Network (EPN) station position time series of approximately 200 GNSS stations subject to the Repro 2 reprocessing campaign in order to characterize the dominant types of noise and amplitude and their impact on estimated velocity values and associated uncertainties. The visual inspection on how different noise model represents the analysed data was done using the power spectral density of the residuals and the estimated noise model and it is coherent with the calculated Allan deviation (ADEV)-white and flicker noise. The velocities resulted from the dominant noise model are compared to the velocity obtained by using the Median Interannual Difference Adjusted for Skewness (MIDAS). The results show that only 3 stations present a dominant random walk noise model compared to flicker and powerlaw noise model for the horizontal and vertical components. We concluded that the velocities for the horizontal and vertical component show similar values in the case of MIDAS and maximum likelihood estimation (MLE), but we also found that the associated uncertainties from MIDAS are higher compared to the uncertainties from MLE. Additionally, we concluded that there is a spatial correlation in noise amplitude, and also regarding the differences in velocity uncertainties for the Up component.

scholarly journals Hybrid intelligence in hospitals: towards a research agenda for collaboration

2021 ◽  
Author(s):  
Milad Mirbabaie ◽  
Stefan Stieglitz ◽  
Nicholas R. J. Frick
Keyword(s):  
Hospital Setting ◽  
Care Process ◽  
Future Research ◽  
Conversational Agents ◽  
Actual Application ◽  
Reasonable Approach ◽  
Hybrid Intelligence ◽  
Application Of Cas ◽  
Successful Collaboration

AbstractSuccessful collaboration between clinicians is particularly relevant regarding the quality of care process. In this context, the utilization of hybrid intelligence, such as conversational agents (CAs), is a reasonable approach for the coordination of diverse tasks. While there is a great deal of literature involving collaboration, little effort has been made to integrate previous findings and evaluate research when applying CAs in hospitals. By conducting an extended and systematic literature review and semi-structured expert interviews, we identified four major challenges and derived propositions where in-depth research is needed: 1) audience and interdependency; 2) connectivity and embodiment; 3) trust and transparency; and 4) security, privacy, and ethics. The results are helpful for researchers as we discuss directions for future research on CAs for collaboration in a hospital setting enhancing team performance. Practitioners will be able to understand which difficulties must be considered before the actual application of CAs.

scholarly journals Deep learning-based transformation of H&E stained tissues into special stains

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Kevin de Haan ◽  
Yijie Zhang ◽  
Jonathan E. Zuckerman ◽  
Tairan Liu ◽  
Anthony E. Sisk ◽  
...  
Keyword(s):  
Visual Inspection ◽  
Kidney Diseases ◽  
Periodic Acid ◽  
Needle Core Biopsy ◽  
Silver Stain ◽  
Periodic Acid Schiff ◽  
Tissue Sections ◽  
Biopsy Tissue ◽  
Hematoxylin And Eosin

AbstractPathology is practiced by visual inspection of histochemically stained tissue slides. While the hematoxylin and eosin (H&E) stain is most commonly used, special stains can provide additional contrast to different tissue components. Here, we demonstrate the utility of supervised learning-based computational stain transformation from H&E to special stains (Masson’s Trichrome, periodic acid-Schiff and Jones silver stain) using kidney needle core biopsy tissue sections. Based on the evaluation by three renal pathologists, followed by adjudication by a fourth pathologist, we show that the generation of virtual special stains from existing H&E images improves the diagnosis of several non-neoplastic kidney diseases, sampled from 58 unique subjects (P = 0.0095). A second study found that the quality of the computationally generated special stains was statistically equivalent to those which were histochemically stained. This stain-to-stain transformation framework can improve preliminary diagnoses when additional special stains are needed, also providing significant savings in time and cost.

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