1,720,978 research outputs found
“Collapsible” lightweight aggregate concrete. Part I: material concept and preliminary characterization under static loadings
No full textIn this work a granular cementitious
composite has been developed, tailoring its performance
to low compressive strength as well as to high deformation
and energy dissipation capacity. This peculiar
performance can be required to the material when
employed in post-installed screeds for protection of
structures and infrastructures against accidental actions
such as impact and blast. The required level of
performance can be achieved through uniform grain
size distribution, paste content as low as minimum
theoretical void ratio and low paste strength. It is
believed that the synergy between the aforementioned
three requirements can allow for energy dissipation
capacity after paste cracking due to both rearrangement
of grainmeso-structure and, in case, grain crushing.This
part I of a companion paper study first of all details the
optimization of the material composition, in terms of
mix-design variables such as w/c ratio, content of air
entraining agent, mixing protocol, paste volume fraction,
grain size distribution of the employed lightweight
expanded clay aggregate. The mechanical performance
of a trial collapsible concrete mix will be then checked.
In part II extensive mechanical characterization under
static and impact loadings will be performed as pertinent
to the intended aforementioned application
“Collapsible” lightweight aggregate concrete. Part II: characterization under static and dynamic loadings
No full textIn this work a granular cementitious
composite has been developed, tailoring its performance
to a low compressive strength and high
deformation and energy dissipation capacity, which
can be required to the material when employed in postinstalled
screeds for protection of structures and
infrastructures against accidental actions such as
impact and blast. The required level of performance
can be achieved by uniform grain size distribution,
paste content as low as minimum theoretical void ratio
and low paste strength: it is believed that the synergy
between the aforementioned three requirements can
allow for energy dissipation capacity after paste
cracking due to both rearrangement of grain mesostructure
and, in case, grain crushing. After the mix
design concept and optimization of the material
composition, illustrated in the first part of this
companion paper study, the mechanical performance
of the composite under static and impact compressive
loadings has been thoroughly characterized, as affected
by mix-design variables, such as paste volume
fraction, water to cement ratio and aggregate size. The
reliability will thus be thoroughly checked, of the
employed material concept, and the influence will also
be investigated, if any, of specimen shape, size and
boundary conditions
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
Cement Penetrability Characteristics in Textile Cement Systems
Full text linkCement penetrability is a key factor in multifilament cement composites. However, the modes of action and the concepts vary because of brittle and ductile fibers. In the case of brittle fibers such as glass, high penetrability of cement products in between the bundle filaments can lead to brittle composite behavior, and therefore addition in ductility is required. In order to have efficient bundle action and high bonding, fillers can be introduced in between the glass filaments, keeping the telescopic mode of failure but at the same time improving the bond and stress transfer within the filaments of the bundle, even at late ages, resulting in a ductile and high strength composite. On the other hand, ductile fibers such as polypropylene (PP), which also developing low bonding with the cement matrix, result in ductile cement composite but with relatively low strength. Therefore, in this case good penetrability of the cement in between the filaments of the bundle is essential in order to maximize the reinforcing efficiency of the bundle by improving bond. The penetrability of the matrix into a fabric structure and especially in between the bundle filaments made up the fabric is a result of fiber- matrix compatibility, which depends on: level of opening and spaces between the filaments, bundle surface properties including wetting and chemical affinity to the cement matrix, matrix viscosity, processing of the composite, and the nature of the fabric junctions and the resulting tightening effects of the bundle, i.e., influenced by the fabric structure itself
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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