1,721,019 research outputs found
Production of lightweight gypsum using a vegetal protein as foaming agent
No full textThe paper deals with the production of lightweight gypsum composites by means of a vegetal protein foaming agent. Two manufacturing methods, which basically differ in the physical state of the foaming agent used, have been proposed and the relative experimental results have been compared and discussed. The gypsum foam samples have been characterized from several points of view (physical, mechanical and microstructural). Thermal and acoustic properties and also porosity have been investigated in order to evaluate the insulation features of the lightweight gypsum composites. The addition of foaming agent strongly affected the mechanical performance of all the samples and led to a significant modification of the post-cracking behavior. Differences observed in the morphology and porosity, related to the two manufacturing methods, are due to the method of pore-formation, especially to the different amounts of air insufflated within the gypsum pastes which influence, in addition to the porosity, the final microstructure and consequently the insulation performances of the gypsum foams. In fact, the more porous samples, obtained from the addition of the liquid foaming agent, showed both the lower values of thermal conductivity and the better values of sound absorption coefficient, leading to a final lightweight products characterized by improved insulation properties
Comparison of latest and innovative silica-based consolidants for volcanic stones
Full text linkThis research explores the new perspectives in conservation and protection of two macroporous tuff stones, widely employed in the architectural heritage of Campania region, characterized by highly heterogeneous rock fabric and texture and a variable mineralogical composition that represent crucial factors responsible for their weak durability. The consolidation treatments were performed with a recently and widely used suspension of nano-silica crystals in water and with a lithium silicate solution that has received up to now scarce attention as a consolidant agent. Physical investigations (open porosity, Hg porosimetry, water absorption), morphological observations (SEM analyses) and visual appearance test (colorimetric measurements), along with assessments of performance indicators such as ultrasonic pulse velocity, surface cohesion test (peeling test) and durability test (salt crystallization), were carried out to investigate the consolidation effectiveness. Overall, lithium silicate consolidant showed a better behavior in terms of superficial cohesion, a most successful strengthening action and a considerable enhancement of salt resistance
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
The bond strength of repairing systems applied to concrete elements: Analysis of historical data
No full textThe use of protection and repairing systems aimed at increasing the durability of concrete structures is a widespread technique. In particular, the use of external thermal insulation composite systems resulted to be a very promising repairing technique enhancing also the insulating behavior of the repaired construction works. This paper examines the performances of several protection systems when applied to concrete standard support elements. The effectiveness of this protection systems is evaluated by means of tests carried out according to ETAG 004 (Guideline for European Technical Approval of External Thermal Insulation Composite Systems "ETICS" with rendering.), before and after ageing (water immersion). The behavior of protection products is determined through the use of standard concrete slab produced according to EN 1776 (Products and systems for the protection and repair of concrete structure-Test methods-Reference concretes for testing). The research activity describes the comparison of different types of protecting materials and systems, produced and tested in a decade (2007-2017), in order to verify different behaviors according to product families and according to the evolution of product mechanical properties
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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