The objective of this study was to characterize the three-dimensional (3D) surface micromorphology of the ceramics produced from nanoparticles of alumina and tetragonal zirconia (t-ZrO2) with addition of Ca(+2) for sintering improvement. The 3D surface roughness of samples was studied by atomic force microscopy (AFM), fractal analysis of the 3D AFM-images, and statistical analysis of surface roughness parameters. Cube counting method, based on the linear interpolation type, applied for AFM data was used for fractal analysis.
View Article and Find Full Text PDFWe propose a nanoindentation technique based on atomic force microscopy (AFM) that allows one to deduce both indentation modulus and hardness of viscoelastic materials from the force versus penetration depth dependence, obtained by recording the AFM cantilever deflection as a function of the sample vertical displacement when the tip is pressed against (loading phase) and then removed from (unloading phase) the surface of the sample. Reliable quantitative measurements of both indentation modulus and hardness of the investigated sample are obtained by calibrating the technique through a set of different polymeric samples, used as reference materials, whose mechanical properties have been previously determined by standard indentation tests. By analyzing the dependence of the cantilever deflection versus time, the proposed technique allows one to evaluate and correct the effect of viscoelastic properties of the investigated materials, by adapting a post-experiment data processing procedure well-established for standard depth sensing indentation tests.
View Article and Find Full Text PDFAn atomic force microscopy (AFM) based technique is proposed for the characterization of both indentation modulus and hardness of compliant materials. A standard AFM tip is used as an indenter to record force versus indentation curves analogous to those obtained in standard indentation tests. In order to overcome the lack of information about the apex geometry, the proposed technique requires calibration using a set of reference samples whose mechanical properties have been previously characterized by means of an independent technique, such as standard indentation.
View Article and Find Full Text PDFAcute indurative cellulite can impair regeneration processes in patients with venous trophic ulcers. Wide range of antimicrobial agents is used for its management, while their role and place remain disputable. The choice of adequate local therapy plays a key role in total success.
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