1,720,997 research outputs found
Characterization and contemporary replicae of Art Noveau coloured glass
No full textCurrently the importance of the application of non-invasive and portable techniques to the characterization of glass is well known. However, despite the large number of publications on medieval glass, few studies have been performed on early modern glass.
Since the opportunities to sample or to move the work of art out of the conservation location are very limited, the application of non invasive and portable techniques appears to be the best way to perform an in-depth characterization of the chromophores and raw materials even though the complexity of interpreting the results and the lack of references necessitate a preliminary phase of testing on standard and reference samples.
In this study a collection of colored and opalescent glasses from the first half of the 20th century and some standard samples of cobalt and cadmium glasses produced ad hoc at the Vicarte Centre (Universidade Nova de Lisboa) were analyzed using both traditional (XRF, SEM-EDS, XRD and UV-Vis-NIR) and portable and non-invasive techniques (XRF, FORS).
The standard samples consist of 21 glasses different base compositions (soda-lime, potash and mixed alkali) and different amounts of chromophores. For cobalt colored glasses different amounts of cobalt (0.5, 0.75 and 1% wt) were added to each base composition (9 samples). Also, yellow to orange and ruby red colorations were obtained by modulating the cadmium/sulfide and cadmium/selenium ratios.
The cobalt blue glass absorption spectra detected by FORS are usually characterized by three sub-peaks located around 530 nm, 590 nm and 650 nm due to the cobalt tetrahedral coordination. A change in the base composition of the glass could, however, affect the three-peak position due to a change in the ligand field strength.
The influence on the FORS spectra of a different base composition and amount of soda present in the glasses (detected by SEM-EDS and XRF) was studied. For glasses with soda content under 15% (some soda-lime samples and mixed base glasses), the resolution of the three-peak absorption band of cobalt is poor. The band appears to be broad, unsymmetrical, and centered around 550 nm even though the characteristic triplet was detected when the amount of soda increased to between 15% and 29%. A shift of about 10 nm in the position of the peaks can be observed in all glasses with a potash base.
The study of the glasses colored by CdS and Se is still in progress, and the results will be available soon
Non-invasive differentiation between natural and synthetic ultramarine blue pigments by means of 250-900 nm FORS analysis
No full textA totally non-invasive procedure has been developed for differentiation of natural and synthetic
ultramarine blue pigments on the basis of collection of UV-visible spectra in diffuse reflectance mode,
followed by a chemometric treatment of the data using unsupervised pattern recognition methods. The
main spectral features of natural and synthetic paint samples, i.e. reflection maxima, inflection points
and reflection minima, could not be useful enough in the differentiation process; a threshold of 455 nm
in the comparison of reflectance maxima has been observed, with synthetic samples peaking lower than
this value and natural samples peaking higher, but it was not considered efficient in the differentiation,
according to the fact that reflection maxima could be subjected to a bathochromic shift as a
consequence of the addition of white pigments to blue paints. Chemometric analysis was therefore
used in order to exploit information contained in the whole spectrum. To obtain an efficient
classification, a proper data transformation was performed on the spectral data, using Z-score
standardised variables. Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) were
the unsupervised pattern recognition methods used on the spectral data. Chemometric treatment was
firstly applied to analysis of standard ultramarine blue paints and powder pigments and showed a good
differentiation power, making it possible to distinguish between paints and raw lapis lazuli items and,
more interestingly, between natural and synthetic ultramarine blue paints. Afterwards, PCA and HCA
were applied to the analysis of blue paints on miniature painting artworks, again succeeding in the
differentiation. This procedure could be used to develop a simple and totally non-invasive method for
authenticating painted artworks
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
Il colore per la fruibilità ampliata delle strutture sanitarie
No full textLa profonda crisi epidemica che sta mettendo in ginocchio i sistemi sociali, politici ed economici di
tutto il mondo apre numerosi scenari di confronto e riflessione anche sui sistemi organizzativi che
riguardano l’assistenza sanitaria, duramente colpita in questo periodo. Occorre ripensare le strutture
sanitarie e socio-assistenziali dal punto di vista tecnologico, impiantistico, architettonico e
sensoriale. La migliore organizzazione degli spazi per il fruitore – paziente, operatore sanitario o
visitatore – richiede un atteggiamento di alto rispetto nei confronti della persona, conformandosi
alle sue complesse necessità, facilitandone i contatti, i percorsi, la permanenza e creando un
ambiente accogliente, rassicurante e mai ostile.
La struttura sanitaria deve garantire non solo la salute dell’individuo ma anche il benessere fisico,
psichico e ambientale suo e degli altri fruitori, riducendo la dannosa Sindrome dell’Edificio Malato
(Sick Building Sindrome; Bodiglio, 2017). Il colore dell’architettura, degli arredi, delle finiture,
della segnaletica – insieme allo studio di suoni, odori, temperatura, umidità, ventilazione,
luminosità, igiene – può giocare un ruolo fondamentale nella rigenerazione degli edifici per la
sanità e nella loro umanizzazione. Inoltre, l’uso sapiente del colore può realizzare sistemi
informativi spaziali che supportino e semplifichino anche l’esplorazione dell’utente all’interno di un
contesto complesso e articolato (Bollini, 2012), addirittura alla scala urbana, come lo è una struttura
sanitaria.
Il rapporto tra colore, salute e benessere è universalmente riconosciuto: un ambiente gradevole ha
un potere terapeutico aggiuntivo e può collaborare alla guarigione, riducendo il periodo di degenza;
anche il personale sanitario, generalmente sottoposto ad attività, orari e rapporti molto stressanti, ne
trae maggiori motivazioni e benefici.
Attraverso l’uso funzionale del colore è possibile quindi trasformare o progettare spazi finalizzati al
comfort ambientale e, contestualmente, migliorare la fruibilità e l’organizzazione dei percorsi, sia
esterni che interni, per supportare quelle sequenze di azioni e procedure che sono anche
strettamente correlate all’incremento del rischio clinico per il paziente o per l’operatore, come sarà
evidenziato nel caso preso in esame.
Sulla base delle sintetiche considerazioni sopra esposte, il presente contributo propone un approccio
metodologico alla “trasformazione/rigenerazione” degli ambienti sanitari e socio-assistenziali,
analizzando in particolare il ruolo del colore nella efficace definizione e comunicazione di
collegamenti, accessi, flussi, funzioni.
Lo studio si inserisce in una ricerca più ampia che tratta la rigenerazione del patrimonio edilizio
funzionale all’assistenza socio-sanitaria e ai più evoluti concetti di housing social
Autenticazione di opere di oreficeria limosina mediante analisi FORS e analisi multivariata
No full textLe opere di oreficeria con smalti vetrosi su metallo costituiscono un settore molto importante dell’arte medievale. Una ricca collezione di oggetti di questa tipologia è conservata in Piemonte, in gran parte legati alla figura del Cardinale Vercellese Guala Bicchieri che le raccolse in tutta l’Europa e le portò in Italia. Insieme a queste opere vi sono oggetti di incerta autenticità, frutto di produzioni ottocentesche e novecentesche create sull’onda di un rinnovato interesse per il Medioevo. Per poter distinguere gli originali medievali e le copie moderne è stato sviluppato un metodo che prevede l’analisi spettrofotometrica in riflettanza diffusa con fibre ottiche (FORS) degli smalti presenti sulle opere, e il trattamento dei dati spettroscopici così ottenuti mediante tecniche di analisi statistica multivariata e in particolare di pattern recognition. L’applicazione ha permesso una netta discriminazione tra smalti limosini di epoca medievale e smalti moderni, confermata in seguito dall’analisi elementare eseguita
mediante XRF
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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