1,720,988 research outputs found
Numerical analysis of soil-pipeline interaction phenomena in unstable slopes
No full textBalkema, Rotterda
Longitudinal pipeline-soil interaction: results from field full scale and laboratory testing
Full text linkThis paper describes some experimental work carried out on the longitudinal pipeline-soil in-teraction problem, within a research program undertaken to increase safety in the manage-ment of Italian-gas distribution network. A longitudinal interaction can be generated by the soil downward movement when a pipeline traverses an unstable slope, mainly along its steepest descend direction. The experimental work aimed at verifying the effectiveness of some interpretative models to represent the soil-pipe interaction phenomenon and to establish reference values for model parameters to assess magnitude of interaction forces, with differ-ent pipe coatings and backfill materials
Evaluation of soil-pipeline longitudinal interaction forces
Full text linkThis work is part of an extensive research program concerning the design of buried pipelines crossing unstable slopes. In these cases the most common choice is that of the pipe axis running parallel to the slope, so that longitudinal interaction is of foremost significance. Soil deformations will influence the pipe, to an extent which depends on pipe-soil interaction; it is desirable that this should be low, so that after exceeding the maximum interface shear strength the soil will deform without further stressing the pipeline. Current methods in use for quantifying shear longitudinal interaction bear some similarity to calculation methods for driven piles. Even though the majority of existing pipelines has been thus designed, these methods are in fact not satisfactory, and some recent research is dedicated to finding new more appropriate methods by means of extensive use of in-situ tests in order to quantify shear strength in soil-structure interaction.
In this paper the traditional methods deriving from pile analogies are examined and their inappropriateness in the case of pipelines is shown. The results of some in-situ tests are examined, and the information that can be drawn is analysed. In addition, the results of some laboratory interface tests are presented. In the aim to create reference values valid for general design rather than for some specific case, these are examined in order to highlight the physical mechanisms responsible for the development of shear strength. Various material combinations are considered, and conclusions are drawn regarding appropriateness of these. Comparison between in situ and laboratory results in part confirms the qualitative analysis of the shear mechanisms; on the other hand, attention is drawn to some physical phenomena, occurring in situ and non reproduced in the laboratory tests
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
Leaching of low-grade manganese ores by using nitric acid and glucose: optimization of the operating conditions
No full textVariations 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
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