Application of Optical Techniques in the Characterization of Thermal Stability and Environmental Degradation in High Temperature Superconductors

Angurel, L.A.; Andrés, Nieves; Pilar, Mara; Recuero, S.; Martínez, Elena; Lera, F.; Pelegrin, Jorge; Manuel, José

doi:10.5772/46938

Cited by 2 publications

(3 citation statements)

References 21 publications

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“…As the value at each interrogation area indicates the local changes, the second procedure allows obtaining a 2D correlation map, with information on where the surface modification process has taken place. The size of the subregions has to be big enough for the statistical analysis to be feasible but as small as the size of the defects to be identified [36].…”

Section: Ndt Methodsmentioning

confidence: 99%

Eco‐Friendly Laminates: From the Indentation to Non‐Destructive Evaluation by Optical and Infrared Monitoring Techniques

Сфарра

Ibarra-Castanedo

Santulli

et al. 2013

Strain

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In this work, the combined effect of indentation damage and of manufacturing defects of a hybrid laminate including jute hessian cloth (plain weave) and hemp fibres in an epoxy matrix has been investigated. With this aim, various non-destructive evaluation (NDE) techniques have been employed, such as near-infrared (NIR) reflectography, infrared thermography (IRT), holographic interferometry (HI) and digital speckle photography (DSP). In particular, two different methods of heating were applied during IRT data collection: pulse thermography and square pulse thermography (SPT). The first one using a mid-wave infrared (IR) camera, while the second one using a longwave IR camera. In the same way, two different cameras working into the near-and short-wave IR spectra were used, to compare different results from $ 0.74 to 14 lm. Data were processed applying principal component thermography (PCT), correlation and the robust secondorder blind identification (SOBI-RO) algorithms. The latter is used for the first time to our knowledge in this work. The defects found were enhanced by image subtraction between the reflectogram and the transmittogram, distance transform and image fusion. In particular, data fusion from IRT and DPS images allowed clearly defining the extension of the indentation damage.

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Section: Ndt Methodsmentioning

confidence: 99%

Eco‐Friendly Laminates: From the Indentation to Non‐Destructive Evaluation by Optical and Infrared Monitoring Techniques

Сфарра

Ibarra-Castanedo

Santulli

et al. 2013

Strain

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“…These materials were stabilized by electroplating a 20 m Cu layer on all sides of the conductor. The sample was mounted in a system prepared to perform simultaneous transport, thermal and optical characterizations [6,7]. Four voltage taps and three thermocouples were soldered to the sample in order to characterize the evolution of the sample in three regions of 1.5, 1.4 and 1.4 cm-long ( Fig.…”

Section: Methodsmentioning

confidence: 99%

“…In this case, characterization has been completed with DSPI observations. These measurements visualize the sample deformation associated with thermal expansion due to heat generated during the current pulse [1,6,7]. As the sample was fixed at the two extremes, this deformation produces a sample bending with a maximum in the center.…”

Section: Dspi Observationsmentioning

confidence: 99%

Changes in the Thermal Stability of 2G HTS Wires by Local Modification of the Stabilization Layer

Angurel¹,

Martínez²,

Pelegrin³

et al. 2011

IEEE Trans. Appl. Supercond.

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Abstract-In order to use 2G HTS wires in superconducting devices, it is important to understand the origin of thermal instabilities in these materials. Previous results showed that inhomogeneities in the critical current distribution are not the only factor that determines the heat generation distribution along the sample when the current exceeds the critical value. In this work, different types of controlled defects have been generated in the Cu-layer using laser ablation. In all cases, laser parameters have been chosen while assuring that the critical current of the superconductor does not deteriorate. It has been obtained that even if the thickness of the stabilizing layer is reduced from 20 m to less than 10 m in some regions, the sample response to overcurrents is not modified.

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Application of Optical Techniques in the Characterization of Thermal Stability and Environmental Degradation in High Temperature Superconductors

Cited by 2 publications

References 21 publications

Eco‐Friendly Laminates: From the Indentation to Non‐Destructive Evaluation by Optical and Infrared Monitoring Techniques

Eco‐Friendly Laminates: From the Indentation to Non‐Destructive Evaluation by Optical and Infrared Monitoring Techniques

Changes in the Thermal Stability of 2G HTS Wires by Local Modification of the Stabilization Layer

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