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- 2017 (3) (entfernen)
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- Englisch (3)
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- Auto-validation (1)
- Core-shell particles (1)
- Electron microscopy (1)
- Fiber Bragg grating (1)
- Image analysis (1)
- Magnetostriction (1)
- Magnetostrictive actuator layer (1)
- Magnetostrictive layer (1)
- PVD /ECD process (1)
- Roughness (1)
Core-shell (CS) particles with a polymeric core and a silica shell play an important role in the materials and (bio)analytical sciences. Besides the establishment of reliable synthesis procedures, comprehensive particle characterization is essential for batch-to-batch reproducibility and objective performance assessment across architectures, protocols, and laboratories. Particle characterization with respect to size, size distribution, shell thickness and texture, surface area and roughness or materials composition is commonly conducted with different analytical methods, often on different samples. Our approach uses a dual-mode TSEM/SEM set-up with an EDX detector to obtain a complementary data set with sufficient statistical confidence of one and the same sample on a single instrument. Our protocol reveals information about size, size distribution and shell thickness of the various particles employed from overview images, while an increased field of view (FOV) and high-resolution EDX analysis yields detailed information on shell texture and elemental composition. An image analysis tool was developed to derive and quantify the profile roughness of CS particles from individual beads. Comparison with surface roughness data from AFM showed a similar trend in roughness across the series of particles. Reliable classification into smooth and rough is proposed and roughness changes within different particle batches were tracked systematically.
Electroplated magnetostrictive actuator layer enabling the external diagnosis of strain sensors
(2017)
Embedded fibre-opticaloptical strain sensors are suitable for structural health monitoring. In order to validate long-term performance (e.g.sensors integrated in airplane wings or wind power turbine blades) an external diagnostics is required.
A strain-detecting region of the optical fibre, the fibre Bragg grating (FBG, is encased by a magnetostrictive layer system serving as actuator. For the validation of the correct sensor function, an external magnetic field introduces mechanical strain resulting in a defined shift of the Bragg wavelength. The layer system is realized by acombined PVD /ECD process optimized regarding magnetostrictive and mechanical properties. The long -term stability of layer adhesion and actuator function has been verified.
An auto-validation tool for the reliability quantification of materials integrated fiber Bragg grating (FBG) strain sensors have been developed and tested. The FBG strain sensor was jacketed with a magnetostrictive layer based on iron-nickel which, when excited by a specific magnetic field, adds an artificial strain to the sensor. The fixed relationship between magnetic induction and wavelength shift of the FBG strain sensor characterizes the bond strength and adhesion between the sensor and the surrounding structure. Due to an easily applicable magnetic field, it is possible to validate the sensor performance in a non-contact, fast way without disturbing the data-acquisition process.