1,720,971 research outputs found
Characterization of yarns from a Flemish tapestry of the XVIth century and a new Keratin/HNT protocol for the conservation of artwork
No full textIn this study, we proposed a physico-chemical approach for the characterization of yarns from a Flemish tapestry of the sixteenth century and a new conservation protocol for the preservation of the artwork. Thermogravimetric analysis (TGA) allowed us to identify yarn fibers and to estimate their life-time. The dynamic mechanical analysis (DMA) provided direct evidence on the aging effect on the yarns, their conservation state and their performance under different mechanical stresses [1]. Besides, the characterization path of yarns was relevant for proposing a novel conservation protocol based on keratin/HNT dispersions, which were explored for coating protection of wool threads. The aqueous dispersions were investigated by Differential Scanning Calorimetry (DSC) measurements to study the mixing enthalpy that can reflect the interaction between the two components in water. [2] The aesthetical effect of Keratin/HNT coating on wool thread was investigated by colorimetric analysis, optical microscopy and scanning electron microscope (SEM) revealing the HNT distribution in the wool fibers. The consolidation and protection effect of Halloysite/Keratin mixtures in wool thread samples were estimated by DMA before and after UV ray irradiation, as aging process. Moreover, the new procedure was tested on a historical yarn from a Flemish tapestry of the sixteenth century as conservation protocol. In conclusion, the results show that the proposed protocol for wool treatment is a promising material as a reinforcing coating for cultural heritage artwork, also increasing mechanical resistance and UV protection, with a minimal impact on the sample aesthetic aspects [3]
HNT/Biopolymers composite materials as a new green alternative for cultural heritage
No full textSynthetic polymers and solvents are dangerous for human health and for the environment, therefore, nowadays scientific community highlights the use of reversible and non-toxic materials toward a green chemistry. Biopolymers, such as Chitosan, Pectin, Hydroxypropyl cellulose, and Keratin, are one of the alternative materials to applied as non-toxic systems, low-cost, sustainable, and environmentally friendly, besides many physico-chemical characteristics. The addition of nanomaterials, (HNT), essential oil, and active molecules improves the physico-chemical properties of biopolymers and proposes smart response abilities to the new composite material in the field of cultural heritage. Two different treatments are presented: a new protective coating for stone artwork with biopolymers filled with halloysite/wax microspheres to prevent surface ageing process; a new consolidation and UV-protection coating for wool thread for cultural heritage consisting halloysite /Keratin dispersion
NEW TREATMENT FOR THE CONSOLIDATION AND THE PROTECTION OF WOOL YARNS FROM A FLEMISH TAPESTRY OF THE XVITH CENTURY
No full textIntroduction
The degradation process of artwork on cultural heritage can be caused by environmental conditions, temperature, UV rays, and humidity, that accelerate the aging process by changing their chemical structure and starting biological attack, alteration, chemical modification, material loss, and interaction between different materials [1].
2. Results and Discussion
New sustainable material made with natural halloysite nanotubes and Keratin was studied for the protection and consolidation of artwork. This innovative green nanocomposite material was tested as a coating layer for the treatment of wool samples, keratin-based on cultural heritage [2]. SEM and optical microscope analysis showed that treated samples were covered without creating any significant variations in the structural shape of the wool. The consolidation % effect of Hal/Keratin treatment was investigated by comparing treated samples at different concentrations of nanotubes with untreated samples. The amino acid cysteine, content on keratin, interacts with wool keratin and cross-links through disulphide bonds restoring wool degradation. After UV exposure of treated and untreated wool samples, the protective efficacy of Hal/Keratin treatment was investigated by mechanical analysis, and it was demonstrated an improvement of stress at breaking (average ca. 30%) and Young Modulus (average of ca. 58%) for treated samples related to the untreated wool sample. Hal/Keratin treatment (R Hal:K=0.5) was applied to a wool historical yarn sample from a Flemish tapestry of the XVI century and analysing tensile properties of treated historical yarn compared to untreated sample, historical yarn acquired mechanical resistance after Hal/K treatment.
3. Conclusions
In conclusion, the application of Hal/Keratin dispersion on historical wool confirmed that is a promising consolidation and protective coating for wool samples. Keratin dispersion allows to create a film as a reinforcing coating for wool damaged, and halloysite nanotubes to enhance the mechanical resistance of wool sample
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
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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