New hydrogels films crosslinked with epichlorohydrin were prepared based on alginates and carboxymethyl cellulose with properties that recommend them as potential drug delivery systems (e.g., biocompatibility, low toxicity, non-immunogenicity, hemostatic activity and the ability to absorb large amounts of water). The characterization of their structural, morphological, swelling capacity, loading/release and drug efficiency traits proved that these new hydrogels are promising materials for controlled drug delivery systems. Further, a new theoretical model, in the framework of Scale Relativity Theory, was built with to offer insights on the release process at the microscopic level and to simplify the analysis of the release process.

The aim of this study is to offer a comprehensive view on drug release from hydrogel, from both an experimental and a theoretical point of view. Aiming to benefit cyclodextrins’ properties (not irritant; stable; able to modify the physical, chemical and biological properties of active compounds; accessible at low prices) and those of carrageenan polysaccharide (antitumor, immunomodulatory, antihyperlipidemic, anticoagulant, biocompatibility, biodegradability), original hydrogel films based on beta cyclodextrin and kappa carrageenan using epichlorohydrin as crosslinking agent were prepared and characterized from morphological and physical/chemical points of view. The results (morphology, the swelling degree, and the loading/release capacity) proved their potential as carriers for different types of drugs. Further, a new theoretical model, from a multifractal paradigm of motion, was proposed for the drug release from hydrogel films, starting from the fundaments of its evolution at a microscopic level, and aiming to obtain information on system evolution, at both the spatial and temporal scales, inapproachable by quantitative measurements.

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Ceramic coatings have many advantages for industrial and medical applications due to their exceptional properties. Ceramic coatings with a thickness of approximately 45 μm, after grinding, were grown using a robotic arm that used the atmospheric plasma spraying procedure. The thermal shock stresses—a common situation in applications but difficult to reproduce under laboratory conditions—of the ceramic layers on top of the metal substrate was achieved using solar energy focused by a concentrating mirror, based on experiments conducted in the CNRS-PROMES laboratory, UPR 8521, belonging to the French National Centre for Scientific Research (CNRS). The ceramic layers showed excellent stability at 1000 °C, even at high heating or cooling rates. At high temperatures (above 1800 °C), the exfoliation of the complex ceramic layer was observed. No differences in the structural, phase, mechanical or adhesion properties of the ceramic layer were observed after the thermal shock cycles (in the literature, there have been quite few reports regarding the properties of the ceramic layers after the thermal shock application). Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), atomic force microscopy (AFM) and X-ray diffraction (XRD) techniques were used to characterize the complex ceramic coating and the effects of thermal shock cycling. The phases and chemical composition of the complex coatings remained similar, insensitive to thermal shock at 1000 °C, consisting of a mixture of crystalline yttrium zirconium oxide and α and γ alumina. For all cases, the main residual stress state was tensile. After 5 or 10 cycles of thermal shocks, a smoothing of the residual stress state was observed in the investigated area. A higher temperature (above 1800 °C), applied as thermal shock, led to higher residual stresses and resulted in large cracks and the spallation of the coating layer.

Preliminary results on the behaviour of metallo-ceramic system during the cutting process were presented. The ceramic layer was obtained, after sandblasting of the substrate, through air plasma spraying with thicknesses of 30 μm on a steel substrate. Layers are chemically homogeneous, without cracks, pores or crevices. The thin layer (30 μm) present discontinuities with uncovered surfaces were the substrate is near in contact with the environment. Cutting process was realized on marking fiber laser equipment (Boron), of 30 watts’ maximum power and wave length of 1064 nm. There were obtained two different grooves on the test pieces with the following parameters: laser double pass at speed of 500 mm/sec, pulsed laser of 20KHz frequency and the beam power was set at 50% (around 15W) for the first groove) and at 80% (around 24W for the second groove). Structural, morphological and chemical evaluation of the cutting kerf was realized using scanning electron microscopy (SEM, Vega Tescan LMHII, SE detector, 30 kV, 15.5 mm WD) and energy dispersive spectroscopy (EDS, Bruker X-flash) using automatic/element list mode, Point, Mapping and Line features. This analysis highlighted the type of defects along the cut, respectively the phenomena occurring at the ceramic - metal interface.