1,720,982 research outputs found
Second harmonic generation at fatigue cracks by low-frequency Lamb waves: experimental and numerical studies
Full text linkAbstract not availableYi Yang, Ching-Tai Ng, Andrei Kotousov, Hoon Sohn, Hyung Jin Li
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
Pyrolysis Model to Simulate the Thermomechanical Behaviour of Cross-Laminated Timber Structures in Fire
No full textCross-Laminated Timber (CLT) walls are crucial components of modern buildings, consisting of multiple layers of timber bonded together. However, as combustible construction materials, their potential fire risk remains a significant concern. The behaviour of CLT components during a fire is complex and requires careful consideration of both (a) the temperature-dependent behaviour of the timber layers and (b) potential chemical reactions (e.g., pyrolysis) within the wood. For (a), the Eurocode EN 1995-1-2 provides guidelines for assessing the fire resistance of timber structures. For (b), this paper applies a pyrolysis model within a Heat Transfer (HT) analysis framework to predict the CLT structural response under fire conditions. This paper introduces and demonstrates a One-Way Coupled (OWC) fire-structure simulation, which combines Computational Fluid Dynamics (CFD) and Finite Element Method (FEM) domains. Inspired by the standard fire test for CLT walls (Osborne et al. 2012), here, CFD is used to reproduce the ISO-834 standard fire as a preliminary demonstration case. Using the thermal data obtained from the CFD model as the boundary condition, a subsequent heat transfer analysis using Abaqus is able to predict pyrolysis and heat transfer behaviour, but it fails to represent the initial temperature distribution (which because of water evaporation is not considered) and capture post-failure behaviour. Additionally, a Structure Response (SR) analysis of the CLT wall under various mechanical loads indicated failures at different times during the fire. However, due to the lack specific information about experimental set-up in the literature, such as mechanical loads and material properties, future studies are planned to verify the model against experimental data.</p
Investigation of Linear and Nonlinear Torsional Guided Waves in Hollow Circular Cylinders for Damage Detection
Full text linkNon-destructive testing plays an important role in structural health monitoring. One of the promising options is the use of guided wave for damage detection in engineering applications, such as pipeline and truss system. Common types of damage in the structures include cracks and corrosion. Guided wave is sensitive to cracks up to micro scale. Long range inspection is the other benefit of using guided wave. The overall aim of this thesis is to present a systematic investigation of guided wave in pipe-like structures to gain physical insights into linear and nonlinear features associated with torsional guided wave interaction with damage.
This thesis includes a number of published and prepared journal papers under the same topic. The overview of linear and nonlinear guided wave, and guided wave mixing is introduced in Chapter 1. A computational model using one-dimensional time-domain spectral finite element with cracked element is presented in Chapter 2. This chapter mainly focuses on linear features of guided wave, such as scattering and mode conversion phenomena. The results show that the proposed cracked model has good agreement between the experimental results and three-dimensional (3D) finite element (FE) simulations.
Nonlinear guided wave is highly sensitive to early stage of micro cracks. Material nonlinearity is one of the nonlinear phenomena in the presence of the micro cracks. It can induce higher-order harmonics of guided wave. Guided wave mixing is the advanced version of nonlinear guided wave since the generation of combinational harmonics at sum and difference frequencies can minimise the effect due to the nonlinearity generated by equipment. Chapter 3 analyses the nonlinear characteristics of two interacting fundamental torsional guided wave modes numerically and experimentally. Chapter 4 and Chapter 5 are the extension parts based on the work in Chapter 3 since pipe-like structures are commonly used in many circumstances, for example embedded pipes and pre-stressed hollow structures. Comprehensive studies in this thesis can gain more understanding for the real applications. In Chapter 4, a 3D FE embedded pipe model with the implementation of nonlinear strain energy function is established to simulate the energy leakage of guided wave propagation due to the existence of soil media. The use of 3D laser scanning system receives guided wave signals from the surface of the pipe for verification. Both numerical and experimental results indicate a significant decline in the interested harmonics at mixed frequency and single frequency. On the other hand, acoustoelastic effect is studied in Chapter 5. A series of case studies are carried out to observe the group velocity change with respect to different levels of loading. The nonlinear features, such as combinational harmonics and second harmonics, are also investigated numerically and experimentally.Thesis (Ph.D.) -- University of Adelaide, School of Civil, Environmental and Mining Engineering, 202
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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