In this paper the influence of high power airborne ultrasound on drying biological material (Lobo apple) properties is considered. Apple samples were dried convectively at 75 ◦C and air flow of 2 m/s with and without ultrasound assist at 200W. During experiments, sun-drenched and not sun-drenched part of fruits were considered separately to show, how the maturity of the product influences dry material properties. Dried apple crisps in a size of small bars were subjected to compression tests during which acoustic emission (AE) was used. Analysis of AE and strength test results shows that correlations between received acoustic signals and sensory attributes (crispness, brittleness) of dried apples can be found. It was noted that ultrasound improved fruit brittleness in comparison with pure convective processes, where fruit maturity determines a kind of destruction and behaviour of dried apple crisps.

The chemistry and microstructure of ceramic coatings of Zr02 with 8 and 20 wt% Y2O3 plasma deposited on the NiCrFe substrate with the NiCr25Al6Fe2Y0.4 interlayer were investigated using scanning, analytical microscopy and X-ray phase analysis. An amorphous phase and fine crystalline zone adjacent to the ceramic and metallic layer was detected using transmission electron microscopy. On the other hand, another zone, which was nanocrystalline with some contribution of amorphous phase was observed in the NiCrAIFeY interlayer close to the NiCrFe substrate.