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Development of measurement procedures and analysis of data from non-destructive tests for the survey of materials and components
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Infrared thermography is a fast, clean and safe technology that is used in a wide variety of applications. Thermography has a number of approaches differing in experiment setup, thermographic technique applied and the way the collected data are processed. Infrared thermography is highly dependent on the sensor selection and the experimental setup. Adequate setup and testing procedures are necessary to avoid questionable results in the thermographic investigation.
This thesis addresses the problems of making the right choices for each specifically application.
Infrared thermography is based on the study of temperature distribution and its evolution with time on the surface of the sample of interest.
Although almost any thermal sensing device is applicable for use in thermographic experiments, modern thermography is generally performed with the use of thermal imagers (cameras). Thermal cameras allow one to obtain two-dimensional images showing the spatial distribution of temperature on the visible surface of the sample under analysis. Modern thermal cameras allow for the fast acquisition of such images, which creates possibilities for a large spectrum of potential experiments.
The second component of a thermographic set up is the source of thermal influence. The primary function of this component is to bring the object of interest out of thermal equilibrium and initiate heat flows and temperature re-distribution in the sample. The choice of the source is highly dependent on the nature of the sample to be studied.
Modern thermographic techniques utilize fast and high precision devices for collection of data about the surface thermal distribution. At the same time, advanced computational processing of collected data is utilized in many modern thermographic approaches for extraction of qualitative and quantitative information on structure and integrity of studied objects.
Even if the measuring chain is almost the same in real applications, each individual part of the measuring chain affects the relation between the source of the infrared radiation and the output signal of the measuring system.
The technological requirements regarding size, design, optical conditions, thermal and spatial resolution and many other framework conditions have to be diversified with respect to a selected experiment. This results in very complex issues that users must solve when trying to design optimum measuring arrangements or conditions. There are no simple rules and the problems cannot be solved without a basic understanding of the correlations. Besides, different algorithms have to be specifically used to extract the right information from the collected data.
In this thesis, the feasibilities of experimentation using thermography are then introduced including the experimental setup. Software and data collection and processing methods used in the current work are introduced and the importance of various variables are studied. From this investigation knowledge of the importance of the experimental parameters is obtained and used in the remainder of experimental work.
In Part I, the background of the material included in this thesis has been provided. Chapter 1 motivates the research and presentes the included publications.
Chapter 2 gives an introduction to the principles of thermal infrared imaging and its applications. It also gives an in depth review of the main types of thermography that use the addition of energy from light sources is then presented.
Chapter 3 gives an overview of the radiation detector principles used in thermal imaging systems: the background knowledge of the operation principles, the limiting factors for the detector performance, and the imaging systems. The acquisition procedure and the processing algorithms have been also introduced for interpretation of the thermal data to extract the features of interest and discussed.
The results are presented in the papers in Part II. Discussions of the case studies are summarized in Section 4.1 and conclusions are provided in Section 4.2.
This thesis has implemented infrared thermography in the important fields of non-destructive testing.
The principles and essential theoretical background in this field have been reviewed. This background information are useful in a better understanding of the problems.
Infrared thermography has experienced a great evolution in a relatively short time. Important improvements were achieved in different fields. However, there is a variety of limitations that need to be considered. Infrared thermography is highly dependent on the sensor selection and the experimental setup. It may be affected by the instrumentation and by the environment. These problems can be minimized, but only with adequate setup, testing procedures and processing algorithms, which mostly depend on the operator’s skill.
Infrared thermography is a mature technique for non-destructive testing. The case studies show that, with an opportune choice of the experimental parameters, this technology can be employed to detect many types of defects and investigates many type of materials
Il procedimento di autorizzazione per gli impianti di produzione energetica da fonti rinnovabili. Complessità e spunti di riflessione
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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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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