1,720,968 research outputs found
Notes on a Asuni pink-marble prospect (Central Sardinia - Italy)". In: "Second International Congress on Dimension Stones
No full textPerformance and issues of diamond wire in ornamental basalt quarries
No full textThe University of Cagliari (Italy) has carried out extensive research on the use and application of diamond wire in basalt quarries, with the objective of assessing the effectiveness of sawing. The focus of the research has been on time-measurements, in order to produce better data about sawing speed rather than what has already been highly documented by diamond wire builders. Net, technical, commercial and gross sawing speeds are calculated, explained and assessed in close context with the sawed parts.The paper gives also an overview of many issues occurring during block squaring, by offering an interpretation of their cause
Raw materials associated with extractive industry: an overview
Full text linkGlobalization, growth in consumption levels and emerging economies such as China and India has led to increasing concerns about the availability of specific mineral raw materials. These resources are finite and rapidly depleting; in the meantime, demand continues to increase. This results in the overall increase in the value of mineral raw material and in the subsequent dramatic price spikes and fluctuations. Therefore, resource security is now a priority for governments of developed countries. The security of supply of the so-called ‘critical’ raw materials (CRM), with rare earths (REE) has attracted the greatest attention in the press. The “criticality” concept is based on the combination of economic importance and supply risk for the Mineral Raw Materials (MRM). The EU relies on extra European countries for the vast majority of their critical raw materials (CRM) supply, putting manufacturing and industrial activities within the EU at risk and causing high economic dependence on non-EU countries. On the other hand, these factors drive a need for new sources of mineral raw materials, and, on the other, a need for the EU to reduce its reliance on global imports of such materials and to become more independent
Particulate matter in fly-ash landfills: an abatement technology using anionic flocculant
No full textThis study aims to assess the use of a mix of anionic flocculant and water, in order to reduce the level of fine dust over the ground in a coal fly-ash landfill. So far, the reduction of dust has been achieved by means of water sprays: this method, however, resulted in high costs incurring in the rental of tank trucks; furthermore, the high consumption of water and diffusion of fuel gas both have a major environmental impact. The new method presented below shows how the creation of a thin film over the landfill can limit both wind erosion and dust emission caused by the transit of vehicles during operations. By collecting samplings of dust and laboratory tests, the authors were able to evaluate effectiveness of above mentioned method from a technical, economical and environmental point of view, which has been subsequently resulted in the Company opting for it
Graffiti removal from granite cladding by abrasive water-jet
Full text linkThis study focuses on the assessment of a graffiti removal system based on abrasive water-jet technology (AWJ). Spray paints were applied on samples of an important Italian granite commercially-named as “Rosa Limbara”. This granite has been used worldwide as dimension stone for paving and cladding. Two different commercial abrasives have been added in the high-pressure water-jet in order to clean the granite saw-plane surfaces from graffiti. After a check by the naked eye, different criteria have been chosen for assessing the effectiveness of the cleaning process: the similarity in roughness (Ra, Rz, and Rmax) between the original surface and the one resulted after cleaning, the total colour difference (ΔE) and the depth of material removed by the AWJ action. The tests showed that excellent cleaning results can be achieved with both abrasives by correctly combining the operational parameters of the technology (i.e., water pressure, spacing between passes, stand-off distance, travel speed and abrasive flow-rate) without giving any damage to the stone material. The two abrasives showed good results in total colour difference although one of them gave better results in both roughness difference and material removal. Economic considerations on paint removal with AWJ technology are also offered
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
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