1,720,959 research outputs found
Calcestruzzi fibrorinforzati con fibre di PET. Studio della resistenza all’impatto
No full textIl riciclaggio dei materiali di scarto è senza dubbio uno dei più importanti problemi da risolvere in futuro in tutti i modi possibili. Sta diventando sempre più necessario trovare soluzioni anche originali, fantasiose e brillanti che devono certamente essere testate prima di essere messe in pratica. Il Polietilene Tereftalato (PET), per esempio, è un materiale di rifiuto che si presta molto bene per essere riutilizzato come rinforzo del calcestruzzo.
Nel presente articolo sono riportati i risultati di alcune prove di impatto effettuate su piastre in calcestruzzo rinforzate con strisce ottenute da bottiglie di scarto in polietilene tereftalato (PET). Le fibre sono state ottenute semplicemente tagliando le bottiglie e sono state utilizzate come rinforzi continui per piastre in calcestruzzo. Per le prove di impatto è stato progettato e realizzato un set-up di prova “ad hoc”. Le prove fanno parte di una estesa ricerca sull’uso del PET come materiale di rinforzo per le strutture in calcestruzzo e in muratura. Le prove hanno fornito dei risultati interessanti circa la resistenza all’impatto del calcestruzzo rinforzato con PET, suggerendo un possibile uso di questo materiale, in particolare per quei casi che sono frequentemente soggetti a shock e a forze di impatto, come i guard-rail new-jersey, le pavimentazioni stradali e aeroportuali, le banchine dei porti. Il rinforzo con il PET ha il vantaggio di non subire fenomeni di corrosione e di essere economicamente vantaggioso rispetto al rinforzo con barre e reti di acciaio, e reti di carbonio o vetro, rendendo questo materiale più adatto per applicazioni in presenza di un ambiente aggressivo.*** Recycling of waste materials is, undoubtedly, one of the most important problems in the future to be solved in all possible ways. It is becoming increasingly necessary to find solutions, even original, imaginative and brilliant to be, of course, first tested before their practical application. Polietilene tereftalato (PET), for example, is a waste material that lends itself well to be reused as concrete reinforcement. In the present article the results of impact tests performed on concrete slab specimens reinforced with fibers made from waste (PET) bottles are reported. The fibers have been obtained by simply cutting the bottles and have been utilized as discrete long reinforcement of the slabs in concrete in substitution of steel bars. A test set-up and slab specimens have been designed and manufactured for the impact tests. The tests are part of an extensive investigation on the use of PET as a reinforcing material in concrete and masonry structures. The tests provided interesting results regarding the impact strength of PET reinforced concrete, suggesting a possible use of this material, in particular for those cases frequently subjected to shocks and impact forces, such as new-jersey guard-rails, road and, especially, airport pavements, wharfs. The reinforcement with PET has the advantage to be less corrosive and less expensive than reinforcement consisting of steel wire nets and carbon or glass nets, making this material more adequate for applications in presence of an aggressive environment
Structural Safety Control of Masonry Buildings: Non-Linear Static Seismic Analysis with a Non-Linear Shear Strength Criterion
No full textThe present paper has the purpose to compare the shear strength obtained using the values proposed by the code for a level of knowledge LC3 [1,2] of a masonry structure with those experimentally obtained from the mechanical tests with flat jacks and the compression tests on stone elements. The shear strength criterion of Mohr-Coulomb has been utilized, applying for the cohesion and friction angle the values obtained by the non-linear criterion of Hoek-Brown for rock masses [3]. For the last criterion an analogy has been assumed between rock mass and masonry; it has been properly adapted to the specific case of masonry structure examined in the paper
Computational Non-linear Analysis Applied to Different Models of Infilled Frames under a Seismic Action
No full textThe presence of infill walls, especially those made of masonry, modifies the behaviour of the structure when
subjected to horizontal forces, with a significant increase of stiffness and strength.
The experience gained over time has shown that this phenomenon of interaction between structure and masonry
and its interpretation is very complex, and consequently difficult to predict.
This paper proposes some different models able to evaluate the effect of infill masonry panels on reinforced
concrete frames subject to a seismic action. The different failure-behaviour of the same structure is considered
both in the case of neglecting the contribution of the external walls and in the case of appropriately consider this
contribution in terms of strength to horizontal forces and collapse mechanism.
Finally the results obtained from the different models assumed for the interacting tufa masonry panels are
compared with the results for a similar bare frame
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
Impact resistance of structural elements in concrete
No full textRecycling of waste materials is, undoubtedly, one of the most important problems in the future to be solved in all possible ways. It will be necessary to find solutions, even original, imaginative and brilliant to be, of course, first tested before their practical application.
In the present article the preliminary results of some static and impact tests performed on concrete specimens reinforced with fibers made from waste polyethilene terephthalate (PET) bottles are reported. The fibers have been obtained by simply cutting the bottles and have been utilized as discrete reinforcement of specimens and little beams in concrete in substitution of steel bars. A specific test set-up has been designed and some slab specimens have been manufactured for the impact tests.
The tests are to be considered an approach to more extensive investigations on the use of PET as a reinforcing material in concrete and masonry structures and they provided interesting results suggesting a possible use of this material in the form of flat or round bars, or networks for structural reinforcement, replacing the more expensive reinforcement consisting of steel wire nets and carbon or glass nets.
Possible applications of PET reinforcement are newjersey guard-rails, road pavements and, especially, airport pavements and all those cases that are more frequently subjected to impact actions and shocks.
The reinforcement with PET has the advantage to be less corrosive and less expensive than reinforcement consisting of steel wire nets and carbon or glass nets
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
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