1,721,151 research outputs found
Numerical modeling of a talc mine exploitation using cemented backfilling
No full textThe Fontane mine (Rodoretto orebody located in Prali near Torino, north west of Italy) is a talc mine irregular vein orebody which is surrounded by a good quality rock mass, gneiss and micaschists). In the past few decades, this underground talc mine has been exploited by conventional cut and fill method using loose fill. Since the seventies, the backfilling has been operated downwards by use of cemented backfill. With this extraction approach, the orebody recovery and the safety of mining operations have been greatly improved. In a new mine section, a numerical modelling has been carried out to study the stress and displacement in the orebody and in the surrounding rock mass of the present condition and with the future development of the mine. The simulation was carried out with a 2D FEM model on relevant cross sections. The numerical modelling has been developed to evaluate how the mine deepening will affect the stability of the fill which was already put in place and of the embedding rock mas
Micromorphology of the fiber post-resin core unit: a scanning electron microscopy evaluation
No full textThe structural characteristics of post-and-core units made with a fiber post and different types of composite resins used as build-up materials in dentistry were investigated. Scanning electron microscopy was used for the analysis. The presence of voids/bubbles within the resin abutment were also detected. A higher homogeneity of the abutment and a better post-core integration were achieved when hybrid composites were used
NEW STUDY TO ASSESS THE GEOMECHANICAL BEHAVIOUR OF THE EXPANSION OF THE RODORETTO TALC MINE
No full textThe paper describes the study carried out in the Rodoretto mine to verify the behavior of the mine infrastructure after a new exploitation extension. Due to a complex geometry and variability in the geology, the new stress distribution around mine infrastructures has been assessed by using numerical methods. Using an ideal elasto-plastic model also the yielding zone distribution has been investigated, especially parameterizing some characteristics which have been found extremely variable during the exploration and investigation proces
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
Limited decalcification/diffusion of self-adhesive cements into dentin
No full textResin cement diffusion into dentin may differ as a function of the pre-treatment regimen. Since self-adhesive cements do not require substrate pre-treatment for luting, penetration of and interaction with the underlying dentin are questioned. We hypothesized that differences in the resin cement diffusion into dentin may exist among current commercial adhesive cements. Composite cylinders were luted on mid-coronal dentinal surfaces by an etch-and-rinse cement (Calibra), a self-etching system (Panavia F 2.0), and 4 self-adhesive cements (Multilink Sprint, Rely X Unicem, G-Cem, Bis-Cem). Dentin/ cement interfacial characteristics were analyzed by a staining technique (Masson's trichrome) and by scanning electron microscopy. Conventional acid etching resulted in partially infiltrated adhesive interfaces differing from those achieved with the application of self-etching primer. No hybrid layer and/or resin tag formation was detectable at the interfaces bonded with self-adhesive cements. Limited decalcification/infiltration was observed for self-adhesive cements into the underlying dentin. Self-adhesive cements were not able to demincralize/dissolve the smear layer completely
Dentin treatment effects on the bonding performance of self-adhesive resin cements
No full textThe effects of dentin surface treatments on the microtensile bond strengths and on the interfacial characteristics of self-adhesive resin cements were investigated. Flat dentin surfaces were obtained from human molars and were treated as follows: (i) no treatment of dentin; (ii) 0.1 M EDTA scrubbed for 60 s; or (iii) 10% polyacrylic acid applied for 30 s. Three self-adhesive cements were used to lute composite overlays on deep-coronal dentin surfaces in the presence of simulated pulpal pressure (15 cm of H(2)O). Bonded specimens were cut into beams 1 mm thick and stressed in tension until failure. Fractured sticks were examined under a scanning electron microscope. Additional specimens were stained with Masson's trichrome and observed under light microscopy for interfacial evaluations. The bond strength to dentin of the hydrophobic and solvent-free cement (RelyX Unicem) was unaffected by the tested dentin treatments. The bond strength of the 2-hydroxyethyl methacrylate (HEMA)-based cement (Bis-Cem) decreased after treatment of dentin with EDTA and/or polyacrylic acid. The hydrophilic and water-containing cement (G-Cem) attained a higher bond strength when luted on polyacrylic acid-conditioned dentin. In conclusion, smear layer removal, opening of dentinal tubules, and the water content of dentin differently influence the bond strengths and the interfacial characteristics of self-adhesive cement-dentin interface
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
Transmission Electron Microscopic Evaluation of a Self-adhesive Material Luted to Different Dental Substrates
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