1,720,987 research outputs found
One-dimensional consolidation of unsaturated pyroclastic soils: Theoretical analysis and experimental results
No full textThis paper synthesizes the results of a study aimed at analyzing the one-dimensional consolidation of unsaturated pyroclastic soils from both theoretical and experimental points of view. In order to pursue this goal, the differential equations governing the problem are firstly derived and their set is solved via the use
of the Finite Difference Method. Input data consist of hydraulic and mechanical parameters whereas output data – changing in space and with time – are the settlement, the pore water pressure and the air pressure of the modelled medium. The values of constitutive parameters appearing in the theoretical model are calibrated on the basis of experimental results achieved from laboratory tests carried out, via a suction controlled oedometer, on specimens of unsaturated pyroclastic soils. Considering that consolidation settlements of unsaturated soils are lower than those experienced by the same soils in saturated conditions (changes in boundary conditions being equal), the followed approach – which combines theoretical and experimental results – can be profitably adopted in geotechnical problems in which the quantitative prediction of consolidation settlement values is a requirement of particular concern
IL RUOLO DELLO STATO INIZIALE DEL TERRENO NELL’INNESCO DELLE COLATE DI FANGO
Full text linkNumerosi studi svolti sull’innesco delle colate di fango nei terreni piroclastici non saturi hanno messo in evidenza il ruolo dello stato di umidità iniziale del terreno prima dell’evento di pioggia innescante. Le grandezze (contenuto di acqua e suzione) che consentirebbero di definire lo stato iniziale non vengono usualmente misurate, ma possono essere ragionevolmente riprodotte in funzione delle piogge che precedono l’evento critico, indipendentemente dalla condizione ipotizzata alla partenza del calcolo. Ciò è vero se l’intervallo di tempo sul quale è svolta l’analisi è sufficientemente lungo da consentire il raggiungimento della condizione idraulica di equilibrio con le condizioni al contorno imposte, seppur variabili nel tempo.
Lo studio è basato su un’analisi a ritroso della frana di Pozzano, frazione di Castellammare di Stabia (Na), avvenuta il 10/01/97, svolta con un approccio disaccoppiato e con l’ausilio dei codici di calcolo SEEP/W e SLOPE/W, che consentono di investigare rispettivamente la risposta idraulica del pendio al variare delle condizioni idrauliche al contorno e la stabilità globale del pendio stesso. Nota la stratigrafia della sezione, le caratteristiche idrauliche e meccaniche dei terreni in esame (ottenute da una campagna di indagine condotta sul territorio dei Monti Lattari), sono stati eseguiti due gruppi di analisi per modellare la risposta del pendio soggetto a piogge di diversa durata e a diverse condizioni di partenza del calcolo. Le serie di pioggia applicate sono state registrate alla vicina stazione pluviometrica di Castellammare di Stabia e culminano con l’evento critico che innescò la frana. Dall’analisi dei risultati si evince che lo stato di equilibrio idraulico nel pendio viene raggiunto nell’arco di pochi mesi precedenti l’evento. Questo risultato consente di determinare l’intervallo temporale a cui estendere lo studio per ricavare lo stato del sottosuolo
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
A new rheometer for mud and debris flow
No full textThe paper presents an innovative laboratory technique aimed at determining the viscous propri-eties of granular materials that are involved in fast landslides. The knowledge of their rheological properties are necessary for assessing the spreading areas that may danger and damage persons and properties (hazard mitigation). The new equipment is a drag ball rheometer, called Sphere Drag Rheometer (SDR). Compared to standard rheometer this system uses much higher volume of mixtures of wider grain size distribution next to that in situ. The procedure to obtain the flow curve are illustrated with reference to Newtonian and Non-Newtonian standard fluids. After calibration procedure the flow curve of some pyroclastic soil-water mixtures are presented. The experimental results on fine mixture are compared with those obtained by conventional rheometrical tools reported in previous papers
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
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