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Biodegradable materials are a further development of new medical applications, such as orthopedic implants and vascular stents, or the tissue scaffold. The variety of alloying elements introduced into magnesium alloys lead to superior corrosion resistance and mechanical properties similar to the biological bone. From a mechanical point of view, increasing the percentage of calcium leads to decreased strength and elongation resistance, and Yttrium addition greatly improves tensile strength and favors a slower degradation process. Three different Mg-0.5Ca-xY alloys were obtained, varying the concentration of the Y-element. The Mg-0.5Ca-xY system was tested from the point of view of micro-scratch and micro-indentation with three determinations each, obtaining results for Young's mode, micro-hardness, COF and stiffness. These alloys possess mechanical properties for use as orthopaedic applications. As future studies, mechanical properties can be improved by performing heat treatments.

The hydraulic turbine blades are made from stainless steels having a hard layer for the improvement of the hydro abrasive wear, corrosion resistance, and resistance to mechanical impacts in order to increase the reliability of the turbine. The thin films from stellite and tungsten carbide were obtained by the method: electrospark deposition because it has relatively low costs, are easy to obtain, the layers have a good adherence to support and the thickness can be variable in function of the established conditions. In this paper, the physical, chemical and mechanical properties of the samples will be determined using Scanning Electron Microscope (SEM), in order to emphasize the structure film-substrate and repartition of the deposition elements on the surface and in transversal section. Also, the samples were nondestructively tested using the electromagnetic sensor with metamaterials in order to establish the adherence of the thin films to the steel, proving the potential of this NDT techniques. The complex signal delivered by the sensor has been stored while scanning a 6x6 mm area. The processing algorithm involve the use of the bidimensional Fourier transform after filtering the initial signal using Walsh-Hadamard numerical filter.

Testing cruciform specimens under static biaxial loading conditions is the method with the best results used to determine the mechanical behavior of materials. A static stress with nonlinear material analysis was applied for only one-eighth of the specimen geometry, due to symmetry conditions, to evaluate stress state from different cruciform specimens subjected to equi-biaxial tension. For the majority of isotropic materials with ductile behavior, such as metals, the most suitable yield criterion used to predict failure is von Mises.

Multiaxial experiments are necessary to determine materials behavior subjected to complex stress state corresponding to real operating conditions under complex loadings. Stresses applied in biaxial experiments are closely to the stresses that materials experience during their function life. Because of reduced acquisition cost, operation cost and maintenance costs devices attached to the universal testing machine are beginning to be used in ever more applications. The present paper examines a new type of mechanism used to test biaxial cruciform specimens in order to evaluate stress state in planar biaxial tensile testing.

The Mohr-Coulomb failure theory presents the major drawback that can be applied only for plane state of stress. In this paper, we propose a modification of the Mohr-Coulomb theory that might eliminate this disadvantage. It is proposed to replace the three Mohr's circles for spatial state of stress with one “virtual circle” with diameter σ1-σ3±2ρ, concentric with the circle that has the diameter σ1-σ3. The triaxial state of stress and biaxial state of stress are considered to be equivalent dangerous.

This paper presents two methods for electromagnetic nondestructive evaluation (eNDE) of composite materials reinforced with carbon woven fibers using a sensor with orthogonal coils and a sensor with metamaterials lens. The samples were impacted with low energy in order to study delamination influence. The electromagnetic behavior of composite was simulated by finite-difference time-domain (FDTD) software, showing a very good concordance with eNDE tests.

In this paper there are presented a series of methods and algorithms for signal processing (A-scan) and image processing (B-scan) which allow an easier and more accurate interpretation of the inspection results. The methods and the algorithms were tested for detection of a buried pipe, made of glass fiber polyester composite with a diameter of 1.3m, first when the survey conditions allowed only the scanning along the pipe, the most disadvantageous situation, but it has imposed by the configuration of the examined zone. After a few days of construction works, the site was prepared for inspection, orthogonally on the first scan direction.

Zinc oxide nanostructured materials, such as films and nanoparticles, could provide a suitable platform for development of high performance biosensing material due to their unique fundamental material properties. This paper presents the characterization of ZnO thin film as biosensing material by metallic strip grating structure (MSG), for the real-time detection. In this work, high quality ZnO films were grown on ITO/glass substrates by vacuum thermal evaporation method. We characterized by X-ray diffraction (XRD) the film crystalline quality and by scanning electron microscopy (SEM) the film morphology.