Phenomenology and Semiotics. Crossing Perspectives.

In recent years the study of relationships between semiotics and phenomenology seems to be entering a period of renewed vitality and creativity (CADIOT & VISETTI 2001; ROSENTHAL & VISETTI 2008; 2010; PIOTROWSKI 2009; FONTANILLE 2008; BONDÌ 2012). For a variety of theoretical and historical reasons, there has been a constant osmosis between phenomenological and semiotic methods. In short, on one side, the works and investigations of phenomenologists have provided essential tools to semiotics. To give just an example: the greimasian semiotics theory refers to the process of meaning formation in terms of perceptual apprehension thanks to his original recovery of Merleau-Ponty’s perception theory. On the other, and at the same time, phenomenology is engaged in describing the activity of language and, in particular, the speaking activity (prise de la parole) of a subject which is a “beingin- the-world” (être-au-monde) and a “being-in-the-language” (être-au-langage): this is the paradigmatic case of Merleau-ponty and of his own model of linguistic gesture as emblem of expression. Furthermore, and more deeply, phenomenology and semiotics are methods rather than disciplines (BORDRON 2011). By means of the epoché, phenomenology has tried to return the articulation of the sensible and of the intelligible, and, on the other, the connections between subjectivity and intersubjectivity. Similarly, semiotics has proposed methods of analysis that are applicable to a wide range of domains:from narrative values to social identities, from textual traces to cultural practices with particular reference to their conditions of emergence. In this simultaneously archaeological and constructive orientation, phenomenology and semiotics have brought new challenges concerning the description of the phases of the meaning constitution

The genus Mauritanica O. Boettger, 1879 (Gastropoda Sty-lommatophora Clausiliidae) in Tunisia

Currently, the genus Mauritanica O. Boettger, 1879 (Gastropoda Stylommatophora Clausiliidae) is widespread in north-eastern Algeria and central-northern Tunisia with six taxa. The taxonomic position of this genus has often been interpreted differently and the relationship with other similar genera, in particular with Siciliaria Vest, 1867, still remains to be clarified. In this paper, we provide a further contribution to the knowledge of Mauritanica by analyzing morphologically (shell, genitalia, and the type museum material) all the known Tunisian populations. In particular, the geographical spread and taxonomy of M. tristrami s.l. (L. Pfeiffer, 1861), M. philora s.l. (Letourneux, 1887), M. perinni polygyra (O. Boettger, 1879), and M. cossoni (Letourneux, 1887) are redefined. Mauritanica perinni zaghouanica (Letourneux, 1887) could be a valid taxon. M. tristrami zribensis n. ssp., M. tristrami nouirasaidi n. ssp. and M. philora bognanii n. ssp. are described

Ultrasonographic changes of submandibular glands in irradiated patients for head and neck cancers

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Physicochemical characterization of passive films on niobium by admittance and electrochemical impedance spectroscopy studies

An analysis of the electronic properties of amorphous semiconductor–electrolyte junction is reported for thin (Dox < 20 nm) passive film grown on Nb in acidic electrolyte. It will be shown that the theory of amorphous semiconductor–electrolyte junction (a-SC/El) both in the low band-bending and high band-bending regime is able to explain the admittance data of a-Nb2O5/El interface in a large range (10 Hz–10 kHz) of frequency and electrode potential values. A modelling of experimental EIS data at different potentials and in the frequency range of 0.1 Hz–100 kHz is presented based on the theory of amorphous semiconductor and compared with the results of the fitting of the admittance data obtained in a different experiment. Some preliminary insights on the possible dependence of the density of state (DOS) distribution on the mobile defects concentration and mechanism of growth of anodic film on valve metals are suggested

Recycling of Heterogeneous Mixed Waste Polymers through Reactive Mixing

Anything that is not recycled and/or recovered from waste represents a loss of raw materials. Recycling plastics can help to reduce this loss and to reduce greenhouse gases, improving the goal of the decarbonization of plastic. While the recycling of single polymers is well assessed, the recycling of mixed plastics is very difficult because of the strong incompatibility among the different polymers usually present in urban waste. In this work, heterogeneous mixed polymers, i.e., polyethylene (PE), polypropylene (PP), polystyrene (PS) and polyethylenetherephthalate (PET) were processed using a laboratory mixer under different conditions of temperature, rotational speed and time to evaluate the effect of the above parameters on morphology, viscosity and mechanical properties of the final blends. Morphological analysis shows a strong incompatibility between the polyethylene matrix and the other dispersed polymers. The blends show, of course, a brittle behavior, but this behavior slightly improves with decreasing temperature and increasing rotational speed. A brittle-ductile transition was observed only at a high level of mechanical stress obtained by increasing rotational speed and decreasing temperature and processing time. This behavior has been attributed to both a decrease in the dimensions of the particles of the dispersed phase and to the formation of a small amount of copolymers that act as adhesion promoters between matrix and dispersed phases

Recent advances on physico-chemical characterization of passive films by EIS and differential admittance techniques

Thin Nb2O5 anodic films (20 nm thick) grown in phosphoric acid solution have been characterised by EIS and differential admittance study in a large range of potential and frequency. The overall electrical behaviour has been interpreted by means of the theory of amorphous semiconductor Schottky barrier in presence of a non-constant density of states (DOS). A comparison of DOS for films grown in different electrolytes is reported

Recyclability of a bio-based biocomposite under different reprocessing conditions

The present paper studies the effect of reprocessing, on both dry and wet reprocessing conditions, on the rheological and mechanical properties of a biocomposite made of a bio-based, biodegradable polymer with 40 wt% wood flour. The results show that the viscosity of the matrix decreases as the number of extrusions increases, with the greatest reduction for samples processed under wet conditions. The same behavior was observed for the biocomposite, but since the viscosity of the biocomposite is much higher than that of the matrix, this causes a greater reduction of molecular weight. Mechanical results show that properties such as tensile strength and elongation decrease as the number of extrusions increases for the matrix. In terms of maximum variations, the tensile strength experiences a decrease of approximately 18%, while the elongation at break shows a more significant reduction of about 40%. Conversely, the biocomposite shows an increase in tensile strength (about 30%) and elongation at break (about 90%) after the first extrusion and then a slight decrease, but with values of tensile strength and elongation higher than those of the virgin biocomposite

Effect of moisture content on the processing and mechanical properties of a biodegradable polyester

This work is focused on the influence of moisture content on the processing and mechanical properties of a biodegradable polyester used for applications in injection molding. The pellets of the biodegradable polyester were exposed under different relative humidity conditions at a constant temperature before being compression molded. The compression-molded specimens were again placed under the above conditions before the mechanical testing. With all these samples, it is possible to determine the effect of moisture content on the processing and mechanical properties separately, as well as the combined effect of moisture content on the mechanical properties. The results obtained showed that the amount of absorbed water—both before processing and before mechanical testing— causes an increase in elongation at break and a slight reduction of the elastic modulus and tensile strength. These changes have been associated with possible hydrolytic degradation during the compression molding process and, in particular, with the plasticizing action of the moisture absorbed by the specimens

An additive model to predict the rheological and mechanical properties of polypropylene blends made by virgin and reprocessed components

In this work, an additive model for the prediction of the rheological and mechanical properties of monopolymer blends made by virgin and reprocessed components is proposed. A polypropylene sample has been reprocessed more times in an extruder and monopolymer blends have been prepared by simulating an industrial process. The scraps are exposed to regrinding and are melt reprocessed before mixing with the virgin polymer. The reprocessed polymer is, then, subjected to some thermomechanical degradation. Rheological and mechanical experimental data have been compared with the theoretical predictions. The results obtained showed that the values of this simple additive model are a very good fit for the experimental values of both rheological and mechanical properties