1,721,048 research outputs found
Scrivere in Oro e in Argento: uno studio multidisciplinare sulla fabbricazione di inchiostri
No full textIl manoscritto BUB 1808, copiato nel Peloponneso intorno alla metà del XIV secolo, conserva una collezione di testi principalmente medici; tuttavia tra cui sono anche presenti alcune ricette sulla preparazione di inchiostri, di cui il nostro manoscritto è l’unico testimone.
L’interpretazione di queste ricette è particolarmente complessa per via della mancanza di quantità esatte, espressioni a volte opache per gli ingredienti e la descrizione non sempre dettagliata delle procedure.
In questo studio abbiamo adottato un approccio interdisciplinare, combinando le nostre competenze di paleografia, filologia, e chimica per affrontare questi problemi.
Per le ricette che non è possibile interpretare in termini di analisi storica e testuale, abbiamo condotto delle repliche sperimentali, che hanno permesso di verificare le nostre ipotesi riguardo ingredienti e procedure, oltre che analizzare i prodotti finali.
Attraverso tecniche di caratterizzazione in fase solida, quali XRPD e ATR-IR, abbiamo ottenuto importanti informazioni sulla composizione dei pigmenti descritti in queste ricette.
La combinazione degli approcci filologico e sperimentale ci ha quindi permesso di raggiungere una comprensione più approfondita delle procedure alla base della preparazione degli inchiostri e della cultura materiale di quel periodo storico.The Bologna University Library’s manuscript 1808, copied in the Peloponnese around the mid-14th century, transmits a collection of mostly medical writings. Among them, we also find a few unedited Greek recipes on the preparation of gold and silver inks for which our manuscript is the sole witness.
Some of these recipes do not specify quantities, feature ingredients with obscure names, and often assume prior procedural knowledge from the reader, making their interpretation a challenging task.
In this paper we adopt an interdisciplinary approach, combining our expertise in paleography, philology, and chemistry to tackle these issues.
For the recipes that could not be interpreted only by means of textual and historical analysis, we conducted experimental replications, that allowed us to assess our hypothesis about the ingredients and the procedures, as well as to characterize the final products. By using solid state characterization techniques, such as X-ray powder diffraction and ATR-IR spectroscopy, we obtained valuable information about the composition of the pigments prepared using these recipes.
This combined textual and experimental approach allowed us to reach a deeper understanding of the processes behind ink-making, and to gain a better insight into the material culture of that time
From Solid-State Structure and Dynamics to Crystal Engineering
No full textThe investigation of the factors responsible for the stability of the diverse crystal forms that a given molecule can adopt in the solid state (polymorphs, hydrates, cocrystals, etc.)
requires an appreciation of the relationship between static and dynamic behavior of atoms and molecules about equilibrium and far from equilibrium positions in the crystal structure. This is particularly relevant when dealing with molecules that are structurally nonrigid at ambient conditions in other media (solution, gas phase). The ease of motion of molecules in molecular crystals depends on the distribution of first neighboring molecules and on the network of intermolecular interactions, which are, in turn, also responsible for the relative thermodynamic stability of solid phases. The knowledge of the intermolecular interactions and of their interplay with the ionic charges commonly present in inorganic, coordination polymers and organometallic compounds is indispensable the application of crystal engineering strategies in the inorganic chemistry area. This microreview article describes, with numerous examples coming mainly from the authors' work, the scientific route that has led from early studies on dynamical processes taking place in the solid state to the design and preparation of novel molecular aggregates involving, inter alia, hydrogen bonded organometallic molecules, charged coordination complexes and metal organic frameworks. The use of solvent-free mechanochemical mixing of reactants as a method of choice for preparing supramolecular aggregates and hybrid organic–inorganic cocrystals will be discussed
Exploring the Ancient Chemistry of Mercury
Full text linkThis paper explores the chemistry of mercury as described in ancient alchemical literature. Alchemy’s focuson the knowledge and manipulation of natural substances is not so different from modern chemistry’spurposes. The great divide between the two is marked by the way of conceptualizing and recording theirpractices. Our interdisciplinary research group, composed of chemists and historians of science, has set offto explore the cold and hot extraction of mercury from cinnabar. The ancient written records have beenperused in order to devise laboratory experiments that could shed light on the material reality behind thealchemical narratives and interpret textual details in a unique perspective. In this way, it became possible totranslate the technical lore of ancient alchemy into the modern language of chemistry. Thanks to thereplication of alchemical practices, chemistry can regain its centuries-long history that has fallen intooblivion
Liquid reagents are not enough for liquid assisted grinding in the synthesis of [(AgBr)(n-pica)]n
Full text linkThis study investigates the mechanochemical reactions between AgBr 3-picolylamine and 4-picolylamine. The use of different stoichiometry ratios of the reagents allows [(AgBr)(n-pica)](n) and [(AgBr)(2)(n-pica)](n) to be obtained, and we report the new structures of [(AgBr)(2)(3-pica)](n) and [(AgBr)(2)(4-pica)](n) which are characterized by the presence of the following: (a) infinite inorganic chains, (b) silver atom coordinated only by bromide atoms and (c) argentophilic interactions. Furthermore, we studied the interconversion of [(AgBr)(n-pica)](n)/[(AgBr)(2)(n-pica)](n) by mechanochemical and thermal properties. The in situ experiments suggest that [(AgBr)(3-pica)](n) is kinetically favoured while [(AgBr)(2)(3-pica)](n) is converted into [(AgBr)(3-pica)](n) only with a high excess of the ligand. Finally, the liquid nature of the ligands is not sufficient to assist the grinding process, and the complete reaction is observed with the addition of a small quantity of acetonitrile
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
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