1,720,974 research outputs found
Investigating the behaviour of existing rockfall protection barriers
No full textThe development of advanced full-scale testing facilities and numerical models has greatly supported the development and the improvement of new rockfall protection barriers (Volkwein et al., 2011), light and versatile steel structures, now capable to arrest falling blocks having capacity up to 8000 kJ. However, the management of existing and comparatively older rockfall protection barriers still remains a crucial issue, notably when rockfall risk assessment is performed along slopes where these structures are found (Bourrier et al., 2014). Within the context, this short note addresses the study of these protection structures, with reference to the case study of the Autonomous Province of Bolzano (PAB)
Metamodeling to emulate plate anchor response in spatially variable soil
No full textThis paper describes a metamodelling approach to investigate the behaviour of a plate anchor in spatially variable soil. The approach explores the effect of variability in undrained shear strength on the monotonic holding capacity. The problem is firstly analysed through a selected number of two-dimensional finite element (FE) analyses. As this is computationally expensive, relatively few analyses are performed, with the metamodel developed to map the response over a wider range of parameters. This uses mathematical operators calibrated to emulate the FE models, which can be built on a relatively small data set, with the overall objective to retain the accuracy of the original FE model at negligible computational cost. In future, this approach may support design by considering uncertainties that are common for any offshore foundation problem, providing a tool that can be easily coupled with traditional probabilistic design approaches
A simple continuum approach to predict the drained pull-out response of piles for offshore wind turbines
Full text linkThe article presents a continuum approach to predict the response of pile foundations for jacket-supported offshore wind turbines. Tensile loading conditions are examined, which may be critical for piles used in combination with this structure type, generally adopted to exploit wind energy in intermediate water depths. The approach is developed to guarantee a simple implementation with a limited number of input data easily attainable from cone penetration tests and laboratory tests, and to ensure computational cost-effectiveness. Data from technical-scale tests on open-ended steel piles driven in dense sand and subjected to drained pull-out are used to assess the performance of the approach. The results are shown to be accurate, approximating rather closely the experimental load–displacement curves. The accuracy of the approach is also compared to that obtained with a recently proposed design method, to investigate the predictive capacity of the approach and its potential to support preliminary design activities
Investigating the Uplift Capacity of Offshore Plate Anchors in Spatially Variable Soils
No full textThis thesis is focused on investigating the behavior of plate anchors in spatially variable soils. The given topic is important because plate anchors are an affordable and robust solution for offshore deep-water wind farms, which are based on floating platforms and have to be fixed in place by anchors buried in seabed. The main focus of the thesis lies on the investigation of undrained behavior of seabed clay under the uplift action exerted by a plate anchor. The aims of this thesis are: generating spatially variable fields of undrained shear strength, developing a reliable FE modeling approach, gathering results in the form of plate anchor bearing capacity for random fields with different spatial properties, validation of the obtained results with respect to the research papers by O'Neill \cite{ONeill} and Cai \cite{CAI}, conducting a parametric study on the chosen statistical properties of generated fields and introducing a promising normalization scheme for obtained values of plate anchor bearing capacity. The most important finding of this thesis is related to the investigation of the suggested normalization approach, the idea of which is to normalize values of plate anchor bearing capacity with respect to the average soil strength across the critical region, where kinematic failure mechanisms develop
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
A New Technique for Deep in situ Measurements of the Soil Water Retention Behaviour
Full text linkIn situ measurements of soil suction and water content in deep soil layers still represent an experimental challenge. Mostly developed within agriculture related disciplines, field techniques for the identification of soil retention behaviour have been so far employed in the geotechnical context to monitor shallow landslides and seasonal volume changes beneath shallow foundations, within the most superficial ground strata. In this paper, a novel installation technique is presented, discussed and assessed, which allows to extend the use of commercially available low cost and low maintenance instruments to characterise deep soil layers. Multi-depth installations have been successfully carried out using two different sensors to measure the soil suction and water content up to 7m from the soil surface. Preliminary laboratory investigations were also shown to provide a reasonable benchmark to the field data. The results of this studyoffer a convenient starting point to accommodate important geotechnical works such as river and road embankments in the traditional monitoring of unsaturated soil variables
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