The objective of the present work is to evaluate the wind potential in the nearshore of the Mediterranean Sea. Thus, a comprehensive picture of the wind conditions is provided by considering 15-year of cumulative information coming from remotely sensed data and from two numerical models. These are provided by the European Center for Medium-Range Weather Forecasts (ECMWF) and the National Centers for Environmental Prediction (NCEP). Since most of the offshore wind turbines usually operate at about 80 m height, the initial wind conditions (reported at 10 m) were adjusted to this height and various wind parameters were evaluated. Besides these, the characteristics of the Vestas V90-3.0MW wind turbine were used to identify the efficiency of this type of generator in terms of operating capacity, rated capacity and capacity factor. From the analysis of these data, it can be noticed that more energetic wind conditions are encountered in the northern part of the basin (close to the Spain-France border and south of Greece) and also in the southern part of the sea (Tunisia sector). In the final part of the paper, based on satellite measurements, the wind conditions (monthly and seasonal) coresponding to some representative locations in the Mediterranean Sea were compared to those from several offshore locations where wind farms already operate.

This chapter means to explain the tribological behavior of polymer-based materials, to support a beneficial introducing of those materials in actual applications based on test campaigns and their results. Generally, the designers have to take into consideration a set of tribological parameters, not only one, including friction coefficient, wear, temperature in contact, contact durability related to application. Adding materials in polymers could improve especially wear with more than one order of magnitude, but when harder fillers are added (as glass beads, short fibers, minerals) the friction coefficient is slightly increased as compared to neat polymer. In this chapter, there are presented several research studies done by the authors, from which there is point out the importance of composite formulation based on experimental results. For instance, for PBT sliding on steel there was obtained a friction coefficient between 0.15 and 0.3, but for the composite with PBT + micro glass beads, the value of friction coefficient was greater. Adding a polymer playing the role of a solid lubricant (PTFE) in these composites and also only in PBT, decreased the friction coefficient till a maximum value of 0.25. The wear parameter, linear wear rate of the block (from block-on-ring tester) was reduced from 4.5 μm/(N⋅km) till bellow 1 μm/(N⋅km) for a dry sliding regime of 2.5…5 N, for all tested sliding velocities, for the composite PBT + 10% glass beads +10% PTFE, the most promising composite from this family of materials. This study emphasis the importance of polymer composite recipe and the test parameters. Also there are presented failure mechanisms within the tribolayer of polymer-based materials and their counterparts.

This paper presents the influence of adding black carbon nanopowder (average size 13 nm, PlasmaChem) in soybean oil in different massic concentration (0.25 %, 0.50 % and 1 %) on several tribological parameters: friction coefficient and wear scar diameter. Tests are done on a four-ball machine. The test parameters were load: 100 N, 200 N and 300 N and speed 1000 rpm, 1400 rpm, 1800 rpm. The test balls are lime polished, made of chrome alloyed steel, having 12.7±0.0005 mm in diameter, with 64-66 HRC hardness. The sample oil volume required for each test was 8±1 ml. This type of anti-wear additive, because the particle distribution is not evenly in contact during the running, could not help improving the tribological behavior. It does not reduced the friction coefficient and wear scar diameter as compared to the neat soybean oil. The authors estimate that the additive should be bonded (physically or chemically) on the triboelements for having better results.

The objective of this paper is to simulate the behavior of unidirectional fabrics, as realistic as possible, in order to be able to use the model in designing impact-resistant packages. There was discussed the influence of the number of layer and the impact velocity on several characteristics as residual velocity of the projectile, its acceleration and the maximum values of von Mises stresses during the impact. Three cases were considered: one layer, two layers and four layers. For all cases, the impact velocity was varied between 100 m/s and 400 m/s, with an increment of 100 m/s, in order to simulate how the panel is damaged. The higher the impact velocity, the stressed area increases when the stress distribution is compared to the stress distribution obtained for v 0 =100 m/s to that for v 0 =300 m/s. At the highest velocity for which the simulation was run, the stressed area has diminished. For the four layer package, for lower velocities, the residual velocity has a lower percentage of the impact velocity, but at high speeds, for this package, the reduction of the residual is even lower (2.7% at v 0 =300 m/s and only 1.75% at v 0 =400 m/s).

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