The Experts below are selected from a list of 207 Experts worldwide ranked by ideXlab platform
Dmitry G Shchukin - One of the best experts on this subject based on the ideXlab platform.
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container based multifunctional self healing polymer coatings
Polymer Chemistry, 2013Co-Authors: Dmitry G ShchukinAbstract:The main aim of this minireview is the demonstration of the recent progress achieved in the development of nanocontainer-based self-healing coatings for the protection of metal structures. This minireview covers the reports published within the last three years. Two main types of nanocontainers – polymer capsules and porous composite inorganic nanoparticles loaded with inhibitors or healing agents – are described. The release of the encapsulated active material is achieved by two main triggers: mechanical rupture of the container shell or changes of the local pH in the Corroded Area. Despite considerable steps made in the field of nanocontainer-based coatings in recent times, challenging problems remain with the mixing of nanocontainers with the coating polymer matrix, effective loading of nanocontainers with inhibitors or healing material and distribution of nanocontainers in the coating matrix.
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Container-based multifunctional self-healing polymer coatings
Polymer Chemistry, 2013Co-Authors: Dmitry G ShchukinAbstract:The main aim of this minireview is the demonstration of the recent progress achieved in the development of nanocontainer-based self-healing coatings for the protection of metal structures. This minireview covers the reports published within the last three years. Two main types of nanocontainers-polymer capsules and porous composite inorganic nanoparticles loaded with inhibitors or healing agents-are described. The release of the encapsulated active material is achieved by two main triggers: mechanical rupture of the container shell or changes of the local pH in the Corroded Area. Despite considerable steps made in the field of nanocontainer-based coatings in recent times, challenging problems remain with the mixing of nanocontainers with the coating polymer matrix, effective loading of nanocontainers with inhibitors or healing material and distribution of nanocontainers in the coating matrix. © 2013 The Royal Society of Chemistry.
Hiroshi Yokoyama - One of the best experts on this subject based on the ideXlab platform.
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the relation between corrosion and surface potential measured with the scanning maxwell stress microscope
Nanotechnology, 1998Co-Authors: Hiroshi Nanjo, Takahito Inoue, Hiroshi YokoyamaAbstract:The topographies and the surface potentials on various Corroded metal surfaces have been simultaneously measured with the scanning Maxwell stress microscope to investigate the microscopic relation between the topography of Corroded surface and the surface potential in atmosphere. In the early stage of corrosion the potential was low at the Corroded region. In the next stage, however, the region where the potential was low at the non-Corroded Area appeared since anodic region transferred from Corroded Area to non-Corroded Area. The microscope is very useful to study the time dependence of the relation between a corroding region and the surface potential.
Daniel Royer - One of the best experts on this subject based on the ideXlab platform.
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Laser ultrasonic inspection of plates using zero-group velocity lamb modes
IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, 2010Co-Authors: D. Clorennec, C. Prada, Daniel RoyerAbstract:A noncontact laser-based ultrasonic technique is proposed for detecting small plate thickness variations caused by corrosion and adhesive disbond between two plates. The method exploits the resonance at the minimum frequency of the S1 Lamb mode dispersion curve. At this minimum frequency, the group velocity vanishes, whereas the phase velocity remains finite. The energy deposited by the laser pulse generates a local resonance of the plate. This vibration is detected at the same point by an optical interferometer. First experiments show the ability to image a 1.5-¿m deep Corroded Area on the back side of a 0.5-mm-thick duralumin plate. Because of the finite wavelength of the S1- zero group velocity (ZGV) mode, the spatial resolution is limited to approximately twice the plate thickness. With the same technique we investigate the state of adhesive bonds between duralumin and glass plates. The S1-Lamb mode resonance is strongly attenuated when plates are rigidly bonded. In the case of thin adhesive layers, we observed other resonances, associated with ZGV modes of the multi-layer structure, whose frequencies and amplitudes vary with adhesive thickness. Experiments were carried out on real automotive adhesively bonded structures and the results were compared with images obtained by X-ray radiography.
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Optimization of Hidden Corrosion Detection in Aircraft Structures Using Lamb Waves: Numerical Predictions and Experimental Results
AIP Conference Proceedings, 2007Co-Authors: N. Terrien, Daniel Royer, F. Lepoutre, A. DéomAbstract:To increase the sensitivity of Lamb waves to hidden corrosion in aircraft structures, a preliminary step is to understand the phenomena governing this interaction. Hence, a hybrid model is used to simulate their interaction with corrosion pits. Numerical results permit to make easier the interpretation of the measured waveforms and thus to optimize the signal processing for detecting pitting at a very early stage. Now, we are able to detect corrosion pits down to 80‐μm depth randomly distributed on a square centimeter of an aluminum plate and to discriminate thickness variations from a slightly Corroded Area.
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Numerical predictions and experiments for optimizing hidden corrosion detection in aircraft structures using Lamb modes
Ultrasonics, 2007Co-Authors: N. Terrien, Daniel Royer, F. Lepoutre, A. DéomAbstract:To increase the sensitivity of Lamb waves to hidden corrosion in aircraft structures, a preliminary step is to understand the phenomena governing this interaction. A hybrid model combining a finite element approach and a modal decomposition method is used to investigate the interaction of Lamb modes with corrosion pits. The finite element mesh is used to describe the region surrounding the corrosion pits while the modal decomposition method permits to determine the waves reflected and transmitted by the damaged Area. Simulations make easier the interpretation of some parts of the measured waveform corresponding to superposition of waves diffracted by the Corroded Area. Numerical results permit to extract significant information from the transmitted waveform and thus to optimize the signal processing for the detection of corrosion at an early stage. Now, we are able to detect corrosion pits down to 80-μm depth distributed randomly on a square centimeter of an aluminum plate. Moreover, thickness variations present on aircraft structures can be discriminated from a slightly Corroded Area. Finally, using this experimental setup, aircraft structures have been tested.
Linglei Zhang - One of the best experts on this subject based on the ideXlab platform.
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laboratory studies on influence of transverse cracking on chloride induced corrosion rate in concrete
Cement & Concrete Composites, 2016Co-Authors: Yongsheng Ji, Yijie Hu, Linglei ZhangAbstract:Abstract To clarify the corrosion mechanism of steel induced by transverse crack, a study on the influence of crack widths and epoxy coating on corrosion of steel bars in cracked concrete is presented here. Microcell and macrocell corrosions of bars were investigated on single crack specimens with crack widths of 0.08, 0.26, 0.38 and 0.94 mm. The entire study was carried out in an artificially created chloride ion-induced corrosion environment. The results show that the steel in cracks was activated once the transverse crack occurred on concrete element, and the macrocell corrosion must co-exist with microcell corrosion of reinforcements in test specimens with transverse crack. The macrocell current of steel elements were separated from the crack width, and the wider the transverse crack is, the higher Corroded Area and the greater microcell current of the rebar is. Oxygen and water go into concrete through crack instead of through concrete cover. The epoxy coating cannot prevent the occurrence and propagation of crack, so it was not effective to prevent corrosion of steel bars in cracked concrete.
A. Déom - One of the best experts on this subject based on the ideXlab platform.
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Optimization of Hidden Corrosion Detection in Aircraft Structures Using Lamb Waves: Numerical Predictions and Experimental Results
AIP Conference Proceedings, 2007Co-Authors: N. Terrien, Daniel Royer, F. Lepoutre, A. DéomAbstract:To increase the sensitivity of Lamb waves to hidden corrosion in aircraft structures, a preliminary step is to understand the phenomena governing this interaction. Hence, a hybrid model is used to simulate their interaction with corrosion pits. Numerical results permit to make easier the interpretation of the measured waveforms and thus to optimize the signal processing for detecting pitting at a very early stage. Now, we are able to detect corrosion pits down to 80‐μm depth randomly distributed on a square centimeter of an aluminum plate and to discriminate thickness variations from a slightly Corroded Area.
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Numerical predictions and experiments for optimizing hidden corrosion detection in aircraft structures using Lamb modes
Ultrasonics, 2007Co-Authors: N. Terrien, Daniel Royer, F. Lepoutre, A. DéomAbstract:To increase the sensitivity of Lamb waves to hidden corrosion in aircraft structures, a preliminary step is to understand the phenomena governing this interaction. A hybrid model combining a finite element approach and a modal decomposition method is used to investigate the interaction of Lamb modes with corrosion pits. The finite element mesh is used to describe the region surrounding the corrosion pits while the modal decomposition method permits to determine the waves reflected and transmitted by the damaged Area. Simulations make easier the interpretation of some parts of the measured waveform corresponding to superposition of waves diffracted by the Corroded Area. Numerical results permit to extract significant information from the transmitted waveform and thus to optimize the signal processing for the detection of corrosion at an early stage. Now, we are able to detect corrosion pits down to 80-μm depth distributed randomly on a square centimeter of an aluminum plate. Moreover, thickness variations present on aircraft structures can be discriminated from a slightly Corroded Area. Finally, using this experimental setup, aircraft structures have been tested.
