1,721,148 research outputs found
Analysing the Main Standards for Climate-Induced Mechanical Risk in Heritage Wooden Structures: The Case of the Ringebu and Heddal Stave Churches (Norway)
Full text linkStudying, controlling and extrapolating the indoor microclimate of historical buildings have always been at the forefront among numerous preventive conservation strategies, especially in case of buildings made of organic hygroscopic materials, e.g., wood. The variations and fluctuations of the microclimatic variables, namely temperature (T) and relative humidity (RH), could have a detrimental effect on the mechanical properties of wooden objects, works of art and structures. For this reason, through the years, several guidelines have been provided by standards and protocols about the optimal microclimatic conditions that should be ensured to avoid the decay and the eventual catastrophic failure of heritage objects and buildings. In this work, two historical buildings entirely made of Scots pine wood have been analysed: the Ringebu and Heddal stave churches (Norway). These churches store several wooden medieval statues and paintings that are also susceptible to the effects of the microclimate. For this reason, the timeseries of the indoor relative humidity of the two churches have been analysed, in the framework of the indications provided by the standards. The criticalities of the existing protocols have been pointed out, emphasizing the need for systematically and periodically updated specifications, tailorable to a given case study of concern, without forgetting the ever-present needs of energy- and money-saving approaches
Novel risk assessment tools for the climate-induced mechanical decay of wooden structures: Empirical and machine learning approaches
Full text linkThe microclimate in which historical buildings and objects are placed strongly influences the mechanical decay and properties of the constituent materials, especially if they are susceptible to fluctuations of temperature (T) and relative humidity (RH). For this reason, in this work, the attention is focused on the indoor microclimate of an historic building completely made of Scots pine wood: Ringebu Church (Norway). In particular, the indoor RH of Ringebu church has been analyzed by means of the European Standard EN15757, which establishes guidelines on assessing whether the RH fluctuations are risky for the conservation of historic hygroscopic materials (such as wood). However, for conservation purposes, it is useful to further study the entity of the RH fluctuations. In this framework, a novel simple strategy, named Median of Data Strategy (MoDS), for identifying RH drops is here proposed; the new approach, by scanning the RH time series and being tested on several examples, displays potential for better assessing the risk of degradation of wooden assets, objects, and artefacts. Then, based on evidence available in literature, a simple empirical model for computing the levels of hygro-mechanical stress developed due to hygric changes has been described and a novel tool for assessing the climate-induced mechanical risk for wooden structures has been proposed. Finally, a machine learning approach for predicting whether climatic fluctuations may have catastrophic effects on the historical wooden materials is presented as well. The obtained results show that the different proposed approaches may be useful for general assessments on the risk of decay of wooden samples and they open a pathway for future investigations in the fields of fracture mechanics, fatigue behavior and smart timeseries prediction for conservation and preservation purposes
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
Granulomatous lesions of the homolateral limb after previous mastectomy
No full textBACKGROUND: Granulomas may be classified as palisaded, sarcoidal, tuberculoid, suppurative and foreign body. In cancer patients they are defined as tumour-related sarcoid granulomas. Otherwise they are classified as granulomatous lesions of unknown significance. It is still unknown why neoplastic diseases are sometimes associated with granulomas. OBJECTIVES: To investigate granulomas found on the same side as a previous mastectomy. METHODS: We studied four women who had previously undergone mastectomy and presented with epithelioid cell granulomas of the same side as the previous mastectomy. CONCLUSIONS: The association between breast cancer and host granulomatous reaction is uncommon. The cases discussed may correspond to cutaneous tumour-related sarcoid granuloma reactions
Modelling the loading rate effects on the fatigue response of composite materials under constant and variable frequency loadings
No full textThis paper discusses the effect of loading rate on the static strength and fatigue behavior of glass/polyester and graphite/epoxy composites. It is shown that the rate-sensitivity of the static strength and the fatigue data can be analytically taken into account in the framework of a two-parameter “residual strength” model, inherently fulfilling the Strength-Life Equal-Rank Assumption (SLERA). Based on the static strength's loading rate sensitivity, a method to use the fatigue life data obtained at any fixed frequencies to predict the fatigue life under different frequencies is proposed. The method's reliability is verified by predicting different data sets of CA fatigue life and residual strength data obtained on glass/polyester composites under different loading rate conditions. The responses of angle-ply carbon/epoxy laminates to arbitrary two-block cyclic loadings in ascending and descending frequency sequences revealed the method's capability to discriminate between the applied loading sequences and the potential to develop a numerical routine accounting for the cycle-by-cycle variability during realistic loading conditions
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
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