1,721,207 research outputs found
Today’s Concretes Exposed to Fire – Test Results and Sectional Analysis
No full textThe well-known capacity of concrete to withstand high temperature and fire is put to the test by the most recent,
high- and ultra high-performance cementitious composites, since their more closed pore structure favours pressure
build-ups in the pores filled with water, turning to vapour at high temperature. The ensuing spalling phenomena
can be prevented by adding polymeric fibres to the mix, while material toughness can be improved – at any
temperature – by adding metallic fibres. However, concrete mechanical behaviour depends on the thermal field,
which is strictly related to the type of fire and to the thermal properties of the material. Hence, special concretes for
special structural applications should be thoroughly characterised at high temperature and after cooling, to
evaluate their thermal and mechanical properties. These properties are recalled in the first part of this paper, with
reference to thermal diffusivity, compressive and tensile strength, elastic modulus and fracture energy.
Furthermore, to maximise the benefits coming from the use of better materials, a parallel rethinking of some
aspects of structural analysis is needed.With regard to this point, in the second part of the paper some suggestions
and proposals are formulated with reference to the analysis of reinforced concrete sections subjected to combined
bending and axial force, and some considerations are made on two rather underrated aspects of the analysis: the
role of the thermal self-stresses and the increasing slenderness of fire-exposed columns
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
Flexural strength and notch sensitivity in natural building stones: Carrara and Dionysos marble
No full textA study of the behaviour of marble beams under four-point bending tests is presented. Two types of marble are considered:
Carrara and Dionysos, which were in the past widely used in buildings in Italy and Greece and are still in use to replace failed or
damaged parts of historic buildings. It is shown that the nominal strength and the global response of a given geometry and load
configuration depend on the specimen sizes. The materials considered did not show a significant notch sensitivity. The presence of a notch is of help in using a crack mouth opening displacement CMOD. control. Thus, it is possible to have stable control over the test and to determine the overall structural response. The achieved nominal strength is compared with the direct tensile strength values and with some theoretical formula
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
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