1,720,976 research outputs found
Progettazione, esecuzione e controllo di rilevati leggeri realizzati in argilla espansa
No full textIl ricorso all’impiego delle argille espanse, spesso abbinato alla tecnica della compensazione dei carichi, è oramai una
pratica comune nella realizzazione di rilevati stradali e/o ferroviari in presenza di strati di terreno cedevole di elevato spessore.
Le argille espanse, grazie ad un peso per unità di volume sensibilmente inferiore a quello dei comuni inerti di cava,
consentono di ridurre i cedimenti associati alla realizzazione dell’opera, incrementare la durabilità della stessa e ridurre i
costi di manutenzione da parte dell’ente gestore. In questa nota, è fornita una panoramica delle principali problematiche
geotecniche attinenti la progettazione di tali opere, con particolare attenzione alla risposta sismica delle stesse. Dopo una
breve introduzione riguardante le caratteristiche delle argille espanse alla micro-scala ed il loro comportamento alla mesoscala,
sono discussi in dettaglio alcuni aspetti di rilevanza pratica, quali le analisi di stabilità, la stima dei cedimenti attesi, le
tecniche di messa in opera e le metodologie di controllo dei manufatti. La nota evidenzia in particolare come l’utilizzo di tali
materiali permetta di ridurre sensibilmente anche i cedimenti permanenti associati a scosse sismiche di elevata intensità
Discussing the definition of the second-order work for unsaturated soils
No full textThe volumetric compaction due to wetting processes is a phenomenon observed quite often in unsaturated soils. Under certain circumstances, saturation events can result into a sudden and unexpected collapse of the system. These phenomena are usually referred to as wetting-induced collapses, without providing any detailed theoretical justification for this terminology. In order to predict in a general fashion the occurrence of coupled instabilities induced by saturation processes, a generalization of the theoretical approaches usually employed for saturated geomaterials is here provided. More specifically, this paper addresses the problem of hydro-mechanical instability in unsaturated soils from an energy standpoint. For this purpose, an extension of the definition of the second-order work is here suggested for the case of unsaturated porous media. On the basis of some examples of numerical simulations of laboratory tests, coupled hydro-mechanical instabilities are then interpreted in the light of this second-order energy measure. Finally, the implications of the theoretical results here presented are commented from a constitutive modelling perspective. Two possible alternative approaches to formulate incremental coupled constitutive relations are indeed discussed, showing how the onset of hydro-mechanical instabilities can be predicted using an extended form of Hill's stability criterion
Stability criteria for unsaturated shallow slopes
No full textThis letter focuses on the mechanical conditions governing the initiation of landslides in unsaturated
shallow slopes. The goal is to provide mathematical criteria for predicting the onset of slope
instabilities and capturing the interplay between saturation conditions and shear failure. For this
purpose, the standard scheme of infinite slope is used and the mechanical response of the deposit is
represented through simple shear kinematics. This assumption enables the study of different
perturbation scenarios using a modelling strategy that: (i) incorporates the constraints describing the
interaction with the pore fluids into the control conditions and (ii) allows the analytical derivation of
stability indices for each scenario. The theoretical results show that, in unsaturated slopes, the
coupling between the solid skeleton and the pore fluid can exacerbate the tendency to undergo
mechanical instabilities. This general aspect is clearly disclosed by the analytical expression of the
stability index for water-undrained shearing. It is found that, because of hydro-mechanical coupling,
the failure mode originated by these perturbations embodies some characteristics of both shear
localisation and static liquefaction. As a result, depending on soil properties and initial conditions, the
unstable response resulting from its activation can resemble either phenomena and predictive
models are necessary to distinguish between the two scenarios
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
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
- …
