1,721,005 research outputs found
Ceramic Industry Air Quality. Emissions Into the Atmosphere From Ceramic Tile Processes
No full textThe subject of this chapter, air quality associated to the ceramic tile industry, represents a very interesting ‘real scenario’ in the framework of the whole volume. The reasons can be summarised in this way: (1) the ceramic tile technology includes several significant pollutant emissions into the atmosphere and (2) ceramic industry has generated – although many years ago and in rather small industrial areas, characterised by large concentrations of factories – some air quality problems. The Ceramic District of Sassuolo, Italy, can be considered as a significant example of such industrial areas and represents the main reference adopted in this chapter. Another ‘ceramic district’ is that of Castellón, Spain, which however is quite different as regards significant factors influencing air quality: factors such as territory, orography, climate, meteorological conditions, urban and industrial settlements and density, road system and traffic, etc. With reference to the Italian ceramic tile industry, this chapter deals with the description and quantification of emissions into the atmosphere from ceramic industries and aims to document the approach adopted, the resources used and the knowledge developed, to drastically reduce the environmental impact of these emissions on air quality. This objective has been successfully achieved, at the point that, in particular, the Italian ceramic tile sector is still working, in the framework of a continuous improvement approach, on its environmental performances, as well as on the exploitation of the results achieved as competitiveness factors
Realizzazione di riporti funzionalizzanti su superfici ceramiche per la produzione di energia elettrica mediante effetto fotovoltaico
No full textThis research, carried out during the PhD in Materials Engineering, deals with the
creation of layers, with different functionality, deposited on a ceramic substrate, to obtain
photovoltaic cells for electricity production.
The research activities are included in the project PRRIITT, Measure 4 (Development of
Networks), Action A (Research and Technology Transfer Laboratories), Thematic reference 3
(Advanced materials applications development), co-financed by the Emilia Romagna Region,
for the creation of CECERBENCH laboratory, which aims to develop "Tiles with a
functionalised surface”.
The innovation lies in the study of materials and in the development of technologies to
achieve a "photovoltaic surface", directly in the tiles production process. The goal is to
preserve the technical characteristics, and to make available new surfaces, exploiting
renewable energy sources. The realization of Building Integrated PhotoVoltaic (BIPV) is
nowadays a more and more spread tendency.
The aims of the research are essentially linked to the need to diversify the actual ceramic tile
production (which is strongly present in the Emilia Romagna Region ), and to provide a
higher added value to the tiles.
Solar energy production is the primary objective of the functionalization, and has a relevant
ecological impact, taking into account the overwhelming global energy demand.
The specific activities of the PhD were carried out according to the achievement of scientific
and technological objectives of CECERBENCH laboratory, and involved the collaboration in
design solutions, to obtain the cells directly on the tiles surface. The author has managed
personally a part of the research project.
Layers with different features were made:
- Electrically conductive layers, directly on the ceramic tiles surface;
- Layers to obtain the photovoltaic functionality;
- Electrically insulating, protective layers (double function).
For each layer, the most suitable materials have been selected. Among the technical
application, the screen printing was used. This technique, widely used in ceramics, has many
application areas, including the electronics and photovoltaic industries. It is an inexpensive
technique, easy to use in industrial production lines.
The screen printing technique was therefore studied in depth by theoretical
considerations, and through the use of rheological measurements
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Effects of hydrofluoric acid etching on lithium disilicate in dentistry
Full text linkScopo dello studio: valutare i cambiamenti indotti da diversi trattamenti di mordenzatura sulla morfologia superficiale e sulla microstruttura di due vetro-ceramiche a base disilicato di litio (IPS e.max® Press e IPS e.max® CAD) ed esaminarne gli effetti sia sull’adesione con un cemento resinoso che sulla resistenza alla flessione.
Materiali e metodi: Settanta dischetti (12 mm di diametro, 2 mm di spessore) di ogni ceramica sono stati preparati e divisi in 5 gruppi: nessun trattamento (G1), HF 5% 20s (G2), HF 5% 60s (G3), HF 9.6% 20s (G4), HF 9.6% 60s (G5). Un campione per ogni gruppo è stato analizzato mediante profilometro ottico e osservato al SEM. Per gli altri campioni è stato determinato lo shear bond strength (SBS) con un cemento resinoso. Dopo l’SBS test, i campioni sono stati caricati fino a frattura utilizzando il piston-on-three-ball test per determinarne la resistenza biassiale alla flessione.
Risultati: L’analisi morfologica e microstrutturale dei campioni ha rivelato come diversi trattamenti di mordenzatura producano delle modifiche nella rugosità superficiale che non sono direttamente collegate ad un aumento dei valori di adesione e dei cambiamenti microstrutturali che sono più rilevanti con l’aumento del tempo di mordenzatura e di concentrazione dell’acido. I valori medi di adesione (MPa) per IPS e.max® CAD sono significativamente più alti in G2 e G3 (21,28 +/- 4,9 e 19,55 +/- 5,41 rispettivamente); per IPS e.max® Press, i valori più elevati sono in G3 (16,80 +/- 3,96). La resistenza biassiale alla flessione media (MPa) è più alta in IPS e.max® CAD (695 +/- 161) che in IPS e.max® Press (588 +/- 117), ma non è non influenzata dalla mordenzatura con HF.
Conclusioni: il disilicato di litio va mordenzato preferibilmente con HF al 5%. La mordenzatura produce alcuni cambiamenti superficiali e microstrutturali nel materiale, ma tali cambiamenti non ne influenzano la resistenza in flessione.Purpose: The aim of this study was to evaluate the changes induced by different etching treatments on the surface morphology and microstructure of two lithium disilicate-based glass ceramic (IPS e.max® Press and IPS e.max® CAD) and examine the effects on the bond strength between ceramic and composite resin and on the biaxial flexural strength.
Materials and methods: Seventy discs (12 mm diameter, 2 mm thickness) of each ceramic were prepared and divided in 5 groups: no treatment (G1), HF 5% 20s (G2), HF 5% 60s (G3), HF 9.6% 20s (G4), HF 9.6% 60s (G5). One specimen for each group was examined by optical profilometer and observed under scanning electron microscopy. On the other specimens was determined the shear bond strength (SBS) with a resin cement. After SBS test, specimens were loaded to failure using a piston-on-three-ball test to determine the biaxial flexural strength.
Results: morphological analysis of treated specimens showed that different etching treatments produces changes in surface roughness but this changes are not directly related to an increasing adhesion value. The SEM analysis revealed that etching causes microstructural changes in lithium disilicate which are more relevant with the increasing of etching time and acid concentration. The mean bond strength values (MPa) for IPS e.max® CAD are statistically higher in G2 and G3 (21,28 +/- 4,9 and 19,55 +/- 5,41 respectively); for IPS e.max® Press, G3 has significant higher adhesion value (16,80 +/- 3,96). The mean biaxial flexural strength values (MPa) are significantly higher in IPS e.max® CAD (695 +/- 161) than in IPS e.max® Press (588 +/- 117). Etching with HF does not affect the flexural strength of the material.
Conclusions: lithium disilicate has to be etched preferably with 5% HF. Etching produces several changes in surface and microstructure of the material, but does not compromise the flexural strength
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