Depth of penetration effects in eddy current testing

The simple depth of penetration equation used for most eddy current calculations does not take into account the effect of the size of the coil or the effect of flaw morphology. The work described in this paper describes use of the CIVA eddy current model to investigate this effect and some experimental investigations. Knowledge of this effect is important in examination of thin sections with eddy currents. Two examples of this are the small sections required to be inspected in laser metal deposition, and welds in thin sections joining dissimilar metals such as copper and aluminium for electrical connections

A pulsed eddy current system for flaw detection using an encircling coil on a steel pipe

Conventional eddy current techniques have been used to a great extent for detection of surface breaking defects in conductive materials. However, detection of sub-surface defects is limited due to skin effect phenomena and material properties. Pulsed Eddy Current (PEC) techniques excite the probe’s driving coil with a repetitive broadband pulse, usually a square wave. The resulting transient current through the coil induces transient eddy currents in the test piece, these pulses consist of a broad frequency spectrum, and the reflected signal contains important depth information. The work in this paper employs COMSOL Multiphysics, the finite element (FE) modelling software, to investigate the behaviour of a new encircling probe design. This work involves modelling of an encircling coil around a steel pipe with high lift-off to simulate insulation. The 3D modelling of the coil wrapped around a steel pipe was employed and surface breaking discontinuities were modelled. The simulation of these scenarios provided essential information about the behaviour of this probe design

Modelling of pulsed eddy current testing of wall thinning of carbon steel pipes through insulation and cladding

Conventional eddy current techniques have been used to a great extent for detection of surface breaking defects in conductive materials. Pulsed Eddy Current (PEC) techniques excite the probe’s driving coil with a repetitive broadband pulse, usually a square wave, instead of sinusoidal wave. The resulting transient current through the coil induces transient eddy currents in the test piece, these pulses consist of a broad frequency spectrum, and the reflected signal contains important depth information. Surface pancake type pulsed eddy current probes have been used for wall thinning and corrosion detection but these methods can be slow. In order to increase the scanned area, an encircling coil has been proposed, with a view to inspect a complete circumference with a single pulse. The work presented in this paper employs COMSOL Multiphysics finite element (FE) modelling software, to further investigate the behaviour of an encircling probe design as a part of the development work. This work involves modelling of an encircling coil around a steel pipe with insulation and cladding of different materials. Pulsed eddy current testing of wall‐thinning through cladding and insulation was studied for various wall thinning situations. The simulation results show the capability of this system in pipe wall thinning detection

The Fabularium:A reflective case study of Practice-as-Research (P-a-R) into outdoor performance training and graduate enterprise delivered at Coventry University 2010-2017.

Original walkabout performance work utilising half-mask Original devised for the Coventry Mysteries Festival in Coventry in 2012, this version was developed and choreographed for International touring opportunities, as a walkabout animation for festivals and as a disruptive intervention in urban locations

Reliability Improvement of Magnetic Corrosion Monitor for Long-Term Applications

Electromagnetic techniques are widely employed for corrosion detection, and their performance for inspection of corrosion is well established. However, limited work is carried out on the development and reliability of smart corrosion monitoring devices for tracking internal or buried thickness loss due to corrosion remotely. A novel smart magnetic corrosion transducer is developed for long-term monitoring of thickness loss due to corrosion at critical locations. The reliability of the transducer is enhanced by using a dissimilar active redundancy approach. The improved corrosion monitor has been tested in the ambient environment for seven months to evaluate the stability against environmental factors and degradation. The monitor is found to show great sensitivity to detect defects due to corrosion. Detection of anomalous patterns in the time series data received from the monitors is accomplished by using Pearson’s correlation coefficient. The critical component of the monitor is identified at the end of the test. Research findings reveal that, compared to the existing corrosion monitoring techniques in the industry, the detection and isolation of faulty sensor features introduced in this study can contribute to reliable monitoring of thickness loss due to corrosion in ferromagnetic structures over an extended period of tim

Promoting ecosystem and human health in urban areas using green infrastructure: A literature review

Europe is a highly urbanised continent. The consequent loss and degradation of urban and peri-urban green space could adversely affect ecosystems as well as human health and well-being. The aim of this paper is to formulate a conceptual framework of associations between urban green space and ecosystem and human health. Through an interdisciplinary literature review the concepts of Green Infrastructure, ecosystem health, and human health and well-being are discussed. The possible contributions of urban and peri-urban green space systems, or Green Infrastructure, on both ecosystem and human health are critically reviewed. Finally, based on a synthesis of the literature a conceptual framework is presented. The proposed conceptual framework highlights many dynamic factors, and their complex interactions, affecting ecosystem health and human health in urban areas. This framework forms the context into which extant and new research can be placed. In this way it forms the basis for a new interdisciplinary research agenda

Wavelet-based PCA defect classification and quantification for pulsed eddy current NDT

A new approach for defect classification and quantification by using pulsed eddy current sensors and integration of principal component analysis and wavelet transform for feature based signal interpretation is presented. After reviewing the limitation of current parameters of peak value and its arrival time from pulsed eddy current signals, a two-step framework for defect classification and quantification is proposed by using adopted features from principal component analysis and wavelet analysis. For defect classification and quantification, different features have been extracted from the pulsed eddy current signals. Experimental tests have been undertaken for ferrous and non-ferrous metal samples with manufactured defects. The results have illustrated the new approach has better performance than the current approaches for surface and sub-surface defect classification. The defect quantification performance, which is difficult by using current approaches, is impressive

Unsettling integration

As part of the three-year project “EPIC”, funded by the Asylum, Migration and Integration fund, this research explores the diversity of responses to migration accross eleven European urban spaces and the different strategies put in place by migrants to navigate and learn the city. To achieve its objective, the project has been designed to establish an international environment for building knowledge and exchanging good practices across multiple partners and sectors. The first chapter examines current migration and integration literature in order to dissect and move beyond the notion of integration. Incorporating policy discourse and academic analyses of integration frameworks and practice, the chapter provides a discursive context for and background to the need for concept revision and to how processes and practices of adaption are perceived of and understood. The second chapter discusses the findings of the surveys and interviews conducted across the eleven cities based on an alternative framework of care, repair and maintenance, drawing out the dominant dimensions and themes within subjective definitions and experiences of ‘integration’. The analysis underlines the importance of recognising the diversity in trajectories of integration, and that policy design should focus on removing obstacles to integration rather than imposing linear integration trajectories. The paper attempts to adopt a reflexive gaze throughout the research to acknowledge the position of power, privilege and in most cases whiteness of the researchers involved. It also recognise the limitations of this type of research and the fact that it is not meant to provide solutions. It wishes, however, to foster further reflections and address the challenges faced by local NGOs and governments

Development of Permanently Installed Magnetic Eddy Current Sensor for Corrosion Monitoring of Ferromagnetic Pipelines

Permanently installed sensors are a cost-effective solution for corrosion monitoring due to their advantages, such as less human interference and continuous data acquisition. Some of the most widely used permanently installed corrosion sensors are ultrasonic thickness (UT) gauges. However, UT sensors are limited by the need for coupling agents between pipe surfaces and sensors. The magnetic eddy current (MEC) method, on the other hand, does not require couplant and can be used over insulations. With the development of powerful rare earth magnets, MEC sensors with low power consumption are possible, and there is the prospect of using them as permanently installed sensors. A novel wireless magnetic eddy current sensor has been designed and optimized using finite element simulation. Sensitivity studies of the sensors reveal that the excitation frequency is a critical parameter for the detection of corrosion defects. An in-depth explanation of the relationship between the sensitivity of the sensor and the excitation frequency is presented in this paper. The results of an accelerated corrosion test, conducted to simulate the service environment of the sensor, are also discussed. It was observed that the sensor signals are very sensitive to corrosion defects and show no subtle differences due to temperature and humidity changes

Parameter analysis of pulsed eddy current sensor using principal component analysis

Pulsed eddy current (PEC) technique provides a means to inspect structures without surface contact. It is particularly useful when the structure’s surface is rough or inaccessible, such as insulated pipes in pipeline. Probe parameters of a PEC system, especially the sensing and excitation coil diameters, can significantly affect the PEC system’s performance. Thus, detailed analysis of these parameters is paramount in developing a PEC system. Currently, this is accomplished by establishing the trend of features with respect to the analyzed variables, e.g. sample thicknesses. However, prior to extracting these features, a number of configuration parameters have to be determined. For this reason, analyzing PEC performance over a range of coil diameter values is rather time-consuming as both the sensing and excitation coil diameters significantly affect the received signals. Principal component analysis (PCA) is proposed as an alternative to the feature extraction. The work here analyzes the trends contributed by the PCA scores for different values of sensing and excitation coil parameters. Results from both numerical simulations and experiments suggest that the sensitivity of the PEC probe is highly correlated with the excitation coil diameter, while the excitation-sensing coil distance is not significant in determining the sensitivity of the PEC probe. These findings are consistent with those reported in the literature, suggesting the potential of adopting PCA for an automated PEC performance analysis process