1,721,253 research outputs found
Effect of episodic pre-failure cyclic loading on whole-life geotechnical properties of soft clays
No full textChanges in soil properties due to loading and consolidation during the life of infrastructure affect the soil response to future events. This concept is encapsulated in the whole-life geotechnical design approach which accounts for the evolution of properties such as strength, stiffness and consolidation coefficient, to improve forecasts of system response through and beyond the design life. This paper explores the changing properties of a soft clay from episodes of pre-failure cyclic loading and consolidation through a series of stress-controlled cyclic direct simple shear (DSS) tests. The scenario is relevant to offshore applications where infrastructure is subject to cyclic seasonal loading, and is particularly relevant to floating offshore wind anchoring systems as these are located in deeper water, farther from shore where soft clays are common. The results quantify the effect of cyclic stress amplitude, number of cycles per packet, and number of consolidation intervals, on the clay properties. The results show increases in undrained strength by up to 70%, stiffness by up to 50% and consolidation coefficient by a factor of up to 30, highlighting the importance of accounting for whole-life effects for reliable and efficient geotechnical design.</p
Changing soil responses during episodic cyclic loading in DSS tests
No full textWhole life geotechnical design is an emerging philosophy in offshore geotechnical engineering to improve design outcomes by considering the whole life of imposed actions coupled with geotechnical properties that evolve with each action. Softening of normally consolidated clays from undrained cyclic loading intervened with consolidation has been shown to lead to hardening, manifested by evolving strength, stiffness, and coefficient of consolidation. This paper presents results from a set of stress-controlled direct simple shear (DSS) tests. The tests follow pre-failure episodic cyclic loading stress paths where each episode comprises a packet of undrained cycles of loads followed by full consolidation. The soil response under different numbers of cycles per loading packet and number of loading packets with intervening consolidation is investigated. The results from this study quantify the effect of the undrained cyclic loading history, for the same final number of cycles, on the evolution of the soil properties, to support the application of whole life geotechnical design in practice. Outcomes allow calibration of design curves that are traditionally used to capture softening, by introducing consolidation effects. This enables capturing the whole life softening and hardening processes, by extending the traditional contour diagram representation for undrained cyclic loading without consolidation to allow for consolidation periods.</p
Changing soil response during episodic cyclic loading in direct simple shear tests
No full textUndrained cyclic loading of normally consolidated clays, interspersed with consolidation (i.e., episodic cyclic loading), hasbeen shown to lead to softening followed by hardening, manifested by evolving parameters such as strength, stiffness, andcoefficient of consolidation. The current evidence base is drawn from tests in which soil strength has been fully mobilized ineach cycle of loading, whereas in practice, changes in stress around a geotechnical infrastructure typically occur only at aprefailure level. This paper presents results from a set of stress-controlled episodic cyclic direct simple shear tests imposingprefailure stress reversals in each cycle. Differences in soil response are identified for the same total number of cycles ofloading but imposed through packets of different numbers of cycles and, consequently, different numbers of interveningconsolidation stages. The results highlight the effect of load history on operational soil properties and quantify the effect ofthe undrained prefailure cyclic loading history on the evolution of the soil properties, supporting the application of wholelife geotechnical design in practice
A Linear-Time Algorithm for Testing Outer-1-Planarity
No full textA graph is 1-planar if it can be embedded in the plane with at most one crossing per edge. It is known that the problem of testing 1-planarity of a graph is NPcomplete.
In this paper, we study outer-1-planar graphs. A graph is outer-1-planar if it has an embedding in which every vertex is on the outer face and each edge has at
most one crossing. We present a linear time algorithm to test whether a given graph is outer-1-planar. The algorithm can be used to produce an outer-1-planar embedding
in linear time if it exists
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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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