1,720,966 research outputs found
Twenty-year monitoring of the Orvieto overconsolidated clayey slope (Italy)
No full textIn addition to landslides of different types and extent, the clayey slope of the Orvieto hill is affected by extremely slow movements at relatively high depths (up to 33 m) and by very slow movements at shallower depths (up to 10 m). These movements are strictly related to rainfall regimes and to the consequent pore pressure distribution inside the hill. The influence of rainfall regimes on the hydraulic conditions and movement rates was reconstructed by means of piezometric and inclinometric measurements performed over the last twenty years
Regime delle piogge, condizioni idrauliche e velocità dei movimenti nelle argille sovraconsolidate del colle di Orvieto
No full textLa rupe tufacea su cui sorge la città di Orvieto è stata interessata sin da tempi storici da fenomeni di instabilità al bordo della rupe connessi al lento movimento del sottostante pendio in argille sovraconsolidate. La strumentazione di controllo installata sin dal 1982 sul versante nord del colle di Orvieto ha messo in evidenza la stretta correlazione fra l'intensità e la durata delle piogge, i livelli piezometrici e gli spostamenti registrati negli inclinometri. In questa nota, i risultati delle misure di controllo vengono presentati e commentati. Viene inoltre descritta brevemente l'attuale attività di ricerca finalizzata all'analisi numerica del regime di filtrazione in condizioni non stazionarie
Influence of rainfall regime on hydraulic conditions and movement rates in the overconsolidated clayey slope of the Orvieto hill (Central Italy)
No full textThe medieval town of Orvieto is built on the top of a pyroclastic slab overlying a gentle slope of overconsolidated clays. The clayey slope has been constantly affected by landslide phenomenona in the form of slow movements and failure events, which in turn have periodically caused the instability of the marginal areas of the pyroclastic slab. Since 1982 a number of Casagrande-type piezometers and inclinometers were installed in the northern slope of the Orvieto hill within the area that was involved in the huge Porta Cassia landslide in 1900.
In this paper, after a brief description of the geology and the geotechnical properties of the slope, data obtained through the monitoring system are illustrated. Piezometric data are utilized to develop a conceptual model of the hydraulic conditions in the clayey slope and inclinometer measurements are interpreted and correlated with the geotechnical ground profile and slope morphology in order to understand the present complex evolution of the clayey slope. Finally, the strong correlation between the rainfall regime, the piezometric levels and the rate of movements is discussed and the recurrence periods of critical cumulative rainfall on displacement trends are estimated on the basis of statistical methods
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
Practical estimate of deformations and stress relief factors for deep tunnels supported by shotcrete
No full textEven though ground-support interaction in the vicinity of the tunnel face is a typical 3D problem,
tunnel support design is usually based on simplified plane strain models, which are strongly
dependent on the assumed degree of ground stress relief at the time of lining installation. The
paper focuses on tunnels supported by shotcrete close to the face, where the interaction between
the loading process and progressive hardening of the green shotcrete makes the problem timedependent.
A constitutive law characterized by the time-dependent stiffness and strength of the
shotcrete is employed herein. The results of an extensive parametric study based on 3D axisymmetric
models are presented in the form of non-dimensional design charts, which can provide
guidance to a preliminary evaluation of convergences and support loadings.
Moreover a strategy is proposed to enhance the capability of simplified design methods (2D
models, Convergence-Confinement Method). This consists in a ‘‘guided estimate’’ of stress relief
factors, which again is based on the results of 3D time-dependent analyses. Finally, by way of
example, the proposed method is applied to two well-documented case-histories.
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
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