1,721,124 research outputs found
Exploring Peirce's Speculative Grammar: The Immediate Object of a Sign
Full text linkThe paper argues against what I call the "Fregean interpretation" of Peirce's distinction between the immediate and the dynamic object of a sign, according to which Peirce's dynamic object is akin to Frege's Bedeutung, while Peirce's immediate object is akin to Frege's Sinn. After having exposed the Fregean interpretation, I briefly reconstruct the genesis of Peirce's notion of immediate object in his semiotic writings of the years 1904-1909 and defend the view that, according to Peirce, only propositions have immediate objects
LBW of similar and dissimilar skin-stringer joints. Part I: Process optimization and mechanical characterization
No full textLaser beam welding of light alloys has always represented a big challenge for both designers and technologists due to the large number of process parameters to take into account and the variable responses of the different materials to be welded. In this paper the results of experimental research on laser beam welds of innovative heat treatable aluminum alloys is reported. The well known T geometry (a stringer welded to a skin) has been considered. Two different skins have been analyzed: AA 2139 and AA 6156, both in form of rolled sheets. Two different stringer have been analyzed: AA 2139 and PA 765, both in form of extruded parts. AA 4047 has been used as filler wire. In the first part of the paper, all the steps leading to the realization of sound welds will be described. The criteria used in order to assess the soundness of a weld was the absence of defects, such as cracks or large pores, verified by means of NDE. In the second part of study, both micro structural analysis and mechanical characterization of welds will be described and discussed. Conclusions will demonstrate the importance of the influence of chemical composition of the parts, above all stringer. The performance of the best welds, however, were very close to those of parent materials
Segnalazione di nuovi depositi piroclastici intercalati alle successioni continentali del Pleistocene superiore-Olocene della porzione nordorientale della Piana Campana.
No full textNuovi dati stratigrafici sul Pleistocene superiore-Olocene della porzione nord-orientale della Piana Campana.
No full textSegnalazione di nuovi depositi piroclastici intercalati alle successioni continentali del Pleistocene superiore-Olocene della porzione nordorientale della Piana Campana.
No full text
Nuovi dati stratigrafici sul Pleistocene superiore-Olocene della porzione nord-orientale della Piana Campana.
No full textEvaluation of roughness and electrochemical behavior of titanium in biological environment
No full textThe increasing use of titanium in the biomedical field arises from the excellent biocompatibility due to the ability to spontaneously become covered with a passive layer. Several studies have shown that some surface treatments can enhance the biological response and corrosion resistance of the implants. The aim of this work is to study the effect of surface treatments of sandblasting and etching with HF on the electrochemical behavior in biological environment and on the roughness of two types of commercially pure titanium, Ti grade 2 and Ti grade 4, used for prostheses and dental implants. The electrochemical characterization has allowed showing that the passive current density increases with the duration of the sandblasting treatment for both alloys. A smaller increase was found in samples subjected to blasting and subsequent etching. It follows that the variation of specific surface induced by blasting is partially canceled by the chemical treatment. The value of passive current density was used to assess the extent of the increase of the real surface of the samples. The roughness analysis showed that the blasting process produces a surface with a large number of peaks, and that the etching with HF tends to level the surface attenuating peaks. The sandblasting and etching treatments, alone or combined, significantly modify the surface of the samples and the magnitude of this change differs depending on the alloy used. Finally, it is proposed to use four roughness parameters to characterize the treated surfaces
Thermo-oxidative ageing of an organo-modified clay and effects on the properties of PA6 based nanocomposites
No full textIn this work a careful investigation on the degradation of an organically modified montmorillonite sample (Cloisite 15A) thermal treated under different atmospheres, namely nitrogen, air and oxygen enriched atmosphere was performed. The exposure time of the thermal treatment ranged between 5 and 300 min. The chemical composition evolution as function of the thermal treatment conditions of the clay organic modifier was monitored by means of combined thermogravimetry/Fourier transform infrared spectroscopy (TGA-FTIR). Moreover, the morphological behaviour of treated Cloisite 15A samples as function of the time and of the decomposition atmosphere was investigated by X-ray diffraction analysis (XRD). In order to understand the possible different interactions of neat and degraded modified clay with a polymeric matrix, PA6 based composites containing 5% of clay were prepared in the melt and fully characterized by a rheological, mechanical and morphological point of view. The results showed t..
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