Axial piston pumps and motors are widely used in heavy-duty applications and play a fundamental role in hydrostatic and power split drives. The mechanical power losses in hydraulic piston pumps come from the friction between parts in relative motion. The improvement, albeit marginal, in overall efficiency of these components may significantly impact the global efficiency of the machine. The friction between slipper and swash plate is a functional key in an axial piston pump, especially when the pump (at low rotational speed or at partial displacement) works in the critical areas where the efficiency is low. The application of special surface treatments have been exploited in pioneering works in the past, trying different surface finishing or adding ceramic or heterogeneous metallic layers. The potential of structured coatings at nanoscale, with superhydrophobic and oleophobic characteristics, has never been exploited. Due to the difficulty to reproduce the real working conditions of axial piston pump slippers, it has been made a hydraulic test bench properly designed in order to compare the performance of nano-coated slippers with respect to standard ones. The nano-coated and standard slippers have been subjected to the following working conditions: a test at variable pressure and constant rotational speed, a test at constant pressure and variable rotational speed. The comparison between standard and nanocoated slippers, for both working conditions, shows clearly that more than 20% of friction reduction can be achieved using the proposed nano-coating methodology.

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Axial piston pumps and motors are widely used in heavy-duty applications and play a fundamental role in hydrostatic and power split drives. The mechanical power losses in hydraulic piston pumps come from the friction between parts in relative motion. The improvement, albeit marginal, in overall efficiency of these components may significantly impact the global efficiency of the machine. The friction between slipper and swash plate is a functional key in an axial piston pump, especially when the pump (at low rotational speed or at partial displacement) works in the critical areas where the efficiency is low. The application of special surface treatments have been exploited in pioneering works in the past, trying different surface finishing or adding ceramic or heterogeneous metallic layers. The potential of structured coatings at nanoscale, with superhydrophobic and oleophobic characteristics, has never been exploited. Due to the difficulty to reproduce the real working conditions of axial piston pump slippers, it has been made a hydraulic test bench properly designed in order to compare the performance of nano-coated slippers with respect to standard ones. The nano-coated and standard slippers have been subjected to the following working conditions: a test at variable pressure and constant rotational speed, a test at constant pressure and variable rotational speed. The comparison between standard and nanocoated slippers, for both working conditions, shows clearly that more than 20% of friction reduction can be achieved using the proposed nano-coating methodology.

A spiny (Palinuridae), slipper (Scyllaridae) and coral (Synaxidae) lobster larval composition and distribution study on the western edge of the Florida Current is presented. From the samples collected during 2007, phyllosoma larvae of Justitia longimanus, Panulirus argus, Parribacus spp., S. americanus, S. depressus and P. gundlachi were positively identified. Relative density catches of the phyllosoma larvae indicate that P. argus (Florida spiny lobster) is the most abundant species in the Straits of Florida. Data gathered during the study shows that P. argus larvae at different developmental stages occur throughout the year which supports the theory of multiple spawning and/or multiple sources. Larvae of genus Panulirus are difficult to distinguish from plankton samples and hence were identified as of P. argus since it is the most common species in the area. Family Palinuridae and Scyllaridae larval density spikes in July and May, coincide with their spawning peak periods of late March – early May and late January to late March respectively. Members of family Palinuridae showed higher densities at night, whereas those of family Scyllaridae showed higher densities during day catches. Larvae of all species showed close association between total length and developmental stage at earlier age. Variability in size and morphology within stage increases with older stages due to multiple molts and/or smaller sample size.

Different special brass (e.g. CuZn37Mn3Al2PbSi) and bronze alloys (e.g. CuPb15Sn) are well known for use in oil-hydraulics having in common to be alloyed with lead. The lead content of special brass alloys in this use ranges from 0.1 to 2.0 mass-%. Some bronze alloys provide even much higher contents of lead of 10 to 15 mass-%. Typically, lead is considered for improvement of machinability or castability. Beyond this purpose lead in brass and bronze alloys affects many more properties of manufacturing and application. During the shaping of the parts by means of hot or cold forming often the materials are strained close to their limits. Thanks to lead cracking is prevented during this process. Lead is also of great importance for the improvement of tribological systems. The surfaces of these systems are exposed to friction and wear. Lead is incorporated in the surface layers and supports the tribological system in their running-in process to achieve a steady state of friction and wear. Above all lead is unique because it forms no solid solution with copper or brass and forms no compounds with other typical copper alloying elements. The feasibility assessment of elements in order to substitute lead in brass or bronze alloys has to be done for each alloy and application individually. In oil-hydraulic applications as bushings, slippers or distributor plates, lead-free alloys must fulfil different profiles of requirements, depending on the conditions of manufacturing and application. The requirements do not only include mechanical strength, formability and thermal strength, but also fatigue strength, low friction and high wear resistance and lubricant compatibility. Consequently, the substitution of lead in brass and bronze alloys for application in oil-hydraulics is a challenging task. This does not only apply for the requirements for machining and forming, but particularly for the need of the new alloys to function under wear, friction and corrosion. Examples are given for how these challenges of new lead-free special brass alloys can be met in bushings (machining, friction properties), slippers (forming, strength) and distributor plates (fatigue strength) for axial piston pumps. Further on, new lead-free special brass alloys for contact with environmentally compatible lubricants are presented. All these examples show that there is not the one and only lead-free alloy for applications in oil-hydraulics. In fact, every application requires a different alloy which is composed and processed individually to meet the specific demands.

Le Soulier de satin, tour à tour perçu comme oeuvre Dada, drame baroque ou pièce àclef, est une oeuvre dont l’étude de la création et la réception permet de mieuxappréhender les liens de Paul Claudel avec son temps. Dans cette pièce, Claudeleffectue la somme de l’héritage artistique de remise en cause de la société positiviste desa jeunesse et livre le récit de sa vocation poétique, enracinée dans la penséebaudelairienne et mallarméenne sur la modernité. La prégnance du paradigme picturalpour livrer son manifeste esthétique et l’utilisation de l’image sous toutes ses formespour entrer en dialogue avec le sens du texte vérifient la concordance d’intérêts entreClaudel et les artistes de sa génération. L’originalité du dramaturge réside dans sonrecours à l’image pour faire de son oeuvre un ex-voto qui retrace l’itinéraire de saconversion, l’inspiration thomiste le conduisant à privilégier l’image dans l’économiedu salut à l’oeuvre dans la pièce. L’oeuvre révèle enfin son affinité avec l’art modernepar son utilisation de procédés et de formes propres à l’art moderne, comme le collageet le montage, ou redécouverts par la modernité, comme l’empreinte ou la planéité,procédés et formes que Claudel emploie de manière polysémique et dialectique. Eninscrivant la question de sa vocation poétique, de sa conversion et de la réception de sonoeuvre par ses contemporains au coeur de la pièce, avec Le Soulier de satin, Claudeldonne une oeuvre qui s’inscrit pleinement dans le programme de la modernité tout enrévélant son originalité propre. / The Satin Slipper has been received alternately as a Dada work, a Baroque drama or a‘pièce à clé’, and studying both its first production and its reception allows one to graspbetter Claudel’s relationships with his days. In this work, Claudel adds up together theartistic legacy of his questioning the positivist society of his youth and gives thenarrative of his poetic vocation, which is rooted in the Baudelairean and Mallarméanthoughts on modernity. Claudel delivers his aesthetic manifesto through the primacy ofthe pictural paradigm and makes the reader establish a dialogue with the meaning of thetext, and all this makes him meet the concerns of the artists of his generation. Theplaywright’s originality lies in his resorting to the image to make his work into an exvoto that traces the itinerary of his conversion, as the Thomistic inspiration drives himto favour the image, in God’s plan at work in the play. Ultimately, the work discloses itscloseness to modern art through the use of devices and forms that are proper to modernart, such as collages and montages, or that were rediscovered by modernity, like theimprint or the planeness, that Claudel uses in a polysemous and dialectical way. As heincludes the questions of his poetic vocation, his conversion and the reception of hiswork by his contemporaries in the heart of the play, Claudel thrusts The Satin Slipperdeeply into the programme of modernity, original though it may be revealed.