3,138 research outputs found
THE INTERTWINED THREADS: CARDS, FRAGMENTS, MEMORIES
No full textThe note is mainly based on the structural bonds that connect the landscape-cultural mosaic. Sometimes there are clear and well-coordinated links, sometimes they are instead fragments of the past or vague intuitions for the future that must be replaced in a coherent framework. By transferring what was affirmed by De Mauro (1990) we can imagine a vague and imprecise conceptual framework where "we speak ill and we understand each other badly", but where interaction and negotiation allow us to refine a possible understanding. The palimpsest is one of the tools that allow time travel, while protocols are those that reduce the likelihood of false interpretations, even if they limit the fantasy of artistic perception. The conclusion recalls the splendid synthesis of the changing fate of the fragments of spiritual and material life that was given by Calvino in one of his invisible cities. Clarice, a city that alternates splendor and misery, succeeds in regenerating and reusing all the material signs of its past, in improper and paradoxical ways, because in the end the order of succession of the eras has been forgotten
Volatiles in cancrinite-sodalite group minerals
No full textThe minerals of the cancrinite-sodalite group are characterized by layers of six-membered rings of tetrahedra: each ring is linked to three rings in a preceding layer and to three rings in the succeeding one, such as to form a three dimensional framework (Bonaccorsi and Merlino 2005). Different stacking sequences give rise to different structures leading to cages, channels and cavities filled by extra-framework anions and cations. Common anions within the structural channels are Cl-, F-, SO42- and CO32-. Recent studies have however shown that carbon dioxide is also a common constituents of these minerals (Della Ventura et al. 2005, 2007a, 2007b). Other possible molecules are H3O+ or HCO3- groups (Gesing and Buhl 2000, Galitskii et al. 1978). IR spectroscopy allows the detection and possibly quantitative analysis of structural H-C-O species, and is thus particular suitable for characterising these minerals.
We relate here the recent developments of our micro-FTIR and crystal-structure studies on a series of cancrinite-sodalite group minerals. Spectra were collected on well-characterized samples, mostly on oriented, doubly-polished slabs, with polarized radiation, using a NicPlan microscope equipped with a nitrogen-cooled MCT detector, a KBr beamsplitter and a ZnSe wire-grid IR polarizer. Microspectrometric mappings were acquired with a Hyperion 3000 Bruker microscope equipped with a computer-controlled motorized stage. HT spectra were collected using a Linkam FTIR600 heating stage (single-crystals) or a Specac HT/HP cell (powders).
Single-crystal FTIR spectra show the common presence of CO2 in most samples, from a wide variety of geological provenance. In particular, systematically high amounts of CO2 are detected in franzinite, nosean and hauyine, while minor but significant amounts are found in vishnevite, marinellite, giuseppettite, vishnevite, davyne and sodalite. Polarized-light spectra collected on [001] sections of hexagonal cancrinite-group minerals show in all cases maximum absorption with E c, suggesting that the linear CO2 molecules are oriented perpendicular the crystallographic c axis of the mineral, like in beryl or cordierite (Aines and Rossman 1984).
Combination of in situ and annealing high-T experiments shows that in the different species the carbon dioxide molecules are bound in different ways within the structure. In addition, release of CO2 occurs at significantly different temperatures due to the different connectivity of the structural pores.
Detailed microspectrometry mappings shows non-homogeneous distributions of hydrogen and carbon across the samples, and suggest a possible use of these minerals as a tool for geothermometric modelling. The finding that most cancrinite-sodalite group minerals are able to trap carbon dioxide opens a new frontier in the design of materials having potential for carbon sequestration from the atmosphere.
References
Aines, R.D., Rossman, G.R. (1984) Am. Mineral., 69 319-327.
Bonaccorsi E., Merlino S. (2005) In G. Ferraris and S. Merlino, eds., Micro- and Mesoporous Mineral Phases, p. 241-290. Reviews in Mineralogy and Geochemistry.
Della Ventura G., Bellatreccia F., Bonaccorsi E. (2005) Eur. J. Mineral., 17, 847-851.
Della Ventura G., Bellatreccia F., Parodi G.C., Cámara F., Piccinini M. (2007a) Am. Mineral. (in press).
Della Ventura G., Bellatreccia F., Piccinini M. (2007b) Rend. Fis. Acc. Lincei (submitted).
Galitskii, V.Yu., Grechushnikov, B.N., Sokolov, Yu.A. (1978) Russian J. Inorg. Chem., 23, 1749-1750.
Gesing, M., Buhl, J.-Ch. (2000) Z. Kristallog., 215, 413-418
Acque e bonifiche a Nonantola dal Medioevo a oggi.
No full textL’acqua, da sempre un elemento fondamentale e insostituibile per gli esseri viventi, costituisce il punto di partenza della mostra itinerante “Aquae. La gestione dell’acqua oltre l’unità d’Italia nella pianura emiliana” dedicata al controllo delle acque e alla salvaguardia del paesaggio nel corso del tempo nei territori oggi identificabili sotto la tutela e gestione del Consorzio della Bonifica Burana. Il 525° anniversario dell’inizio dello scavo del “Cavamento Foscaglia”, imponente opera idraulica realizzata a partire dal 1487 grazie a un accordo tra gli Estensi di Ferrara e i Bentivoglio di Bologna, ha fornito il pretesto per avviare un percorso di ricerca storica e informazione che coinvolgesse tutte le istituzioni più competenti in materia. L’obiettivo era aumentare la consapevolezza che l’assetto idrologico del territorio in cui viviamo è frutto del lavoro di ogni civiltà che vi si è avvicendata, un'opera collettiva che potrà essere conservata, migliorata e consegnata alle generazioni future solo se viene rispettata da tutti.
La guida è stata pubblicata in occasione della seconda tappa della mostra itinerante a Nonantola (Mo) per approfondire il rapporto fra acqua, uomo e territorio, rintracciando i legami e le interconnessioni esistenti per una conoscenza sempre più ampia della nostra storia. Il volume ripercorre l'evoluzione del paesaggio padano dalla preistoria ai giorni nostri con particolare attenzione al punto di vista del controllo delle acque e con l'aggiunta di alcuni approfondimenti dedicati alla gestione delle acque nel territorio nonantolano e alla Partecipanza agraria di Nonantola. Particolare attenzione è stata posta alla romanizzazione della pianura, con una finestra sulla centuriazione, tipica forma di governo del territorio che in vaste zone della pianura padana si è mantenuta fino ad oggi. Uno degli studi più interessanti fa riferimento al primo documento relativo all'attuale Canal Torbido, un discusso diploma risalente al 752 con cui il re longobardo Astolfo concede a S. Anselmo, fondatore della chiesa e del monastero di Nonantola, la Selva Gena, attraversata dall’omonimo corso d’acqua indicato nella cartografia antica con il nome di Gena o Zena (da non confondersi con lo Zena attuale), che prenderà in seguito il nome di Canale di Nonantola e infine di Canal Torbido. Con la caduta dell’impero romano, cambia completamente l’assetto paesaggistico del territorio: vaste zone vengono sottratte al controllo dell’uomo e subiscono un progressivo impaludamento; nascono così insediamenti fortificati (castrum), circondati da canali e fossati difensivi. Solamente con la fine del Medioevo, l’uomo inizia una nuova attività di bonifica e riordino della pianura, che interessa anche una vasta area localizzata alla destra e alla sinistra del Panaro. All’interno di questa fase ricade il trattato stipulato fra Giovanni II Bentivoglio e Ercole I d’Este per la realizzazione della prima grande opera di bonifica idraulica, il Cavamento Foscaglia meglio noto come Collettore delle Acque Alte.
L’attenzione viene focalizzata anche sui territori dei Pico e dei Gonzaga che adottavano il sistema dei “serragli” per arginare l’invasione delle acque. Tutto ciò anticipa una vera e propria politica nazionale di miglioramento fondiario che inizia in modo sistematico con l’unità nazionale ed arriva ad oggi. In questa operazione è risultato fondamentale il controllo delle acque e il loro governo attraverso un’unica struttura che unisce la montagna alla pianura e rafforza le comunità sotto un grande denominatore comune: il Consorzio di Bonifica
D. Freda, M. Piccinini, H. Pihlajamäki, C.M. Valsecchi (a cura di), Borders of the Early Modern Ius Commune. England, Venice and Scandinavia, Routledge, London & New York 2025.
No full textFROM ORDER TO ERRATICITY
No full textAccording to the laws of physics, order has a cost, in terms of the creation of some form of disorder somewhere else, as the entropy states. The paper considers examples taken from everyday’s life, and their empirical solutions. There exist exact methods for creating and maintaining order, found at the origin of artificial intelligence by Simon, referred to as linked lists. Unlike what is generally supposed erraticity is not a pure randomness problem, but rather must take into account actual bifurcations, possibly not reversible. Since we are interested also on the cultural side of mosaic, it is correct to start from persons whose life has been important, but erratic, with relevant turns in their activity, or in their long time fortune. The examples we give, should suggest the reader to look for other examples according to his own inspiration. An exercise, that is only sketched in the paper, is to look for the turning points that we can find in the history of landscape or in the history of towns. When does erraticity arise, how long does it remain undefined and subject to randomness, when becomes irreversible
FTIR imaging: new opportunities in earth sciences
No full textFourier-transform infrared (FTIR) microscopy is a modern analytical technique able to provide a molecular imaging of a complex sample. With this technique, based on the absorption of IR radiation by vibrational transitions in covalent bonds, unique images with a high spatial resolution can be obtained from a sample. The spatial resolution of an infrared microscope, as defined by the diffraction limit, is about 2λ/NA, i.e., from 3 to 4 times the wavelength depending by the NA (numerical aperture) of the instrument. In these last decades the availability of solid-state array detectors revolutionized the fields of molecular spectroscopy and chemical imaging. Nowadays, 2-dimensional IR detectors, Focal Plane Arrays (FPAs), coupled to synchrotron radiation sources allow achieving the highest sensitivity and the highest resolution of molecular imaging in a short time. FPA arrays, composed by small IR detectors (pixels), allow the acquisition of thousands of IR spectra simultaneously and generate mid-IR images with high resolving power, thus improving performances of IR imaging systems equipped by conventional IR sources. A microscope equipped with a FPA has no apertures and its sensitivity is associated to the pixel size: the effective “aperture” of the optical system. FPAs enable different imaging modalities with a resolution of a few microns (depending on the pixel size and magnification of the objective). Massive and fast data collection is possible with a drastic reduction in the acquisition time compared to a confocal geometry. Experiments performed with conventional instrumentations have clearly shown that combining the sensitivity and the speed of read-out of the last generation of FPAs the time may scale down from hours to minutes (Barghawa and Lewin, 2001, Petibois et al., 2008). H-C-O functional groups are characterized by highly polar bonds and absorb infrared radiation with high efficiency, therefore FTIR micro-spectroscopy may be used to qualitatively and quantitatively measure these elements in geological materials (both minerals and glasses) with a high-spatial resolution (Wysoczanski and Tani, 2006; Della Ventura et al., 2009). We will present here and discuss new applications of infrared imaging, with particular reference to the distribution and speciation of H and C in a variety of mineralogical samples, including single-crystals (microporous minerals, NAMs, fluid inclusions) and thin sections, as well as the use of FTIR imaging in high-temperature studies.
References
Barghawa, R. and Lewin, I. (2001) Anal. Chem. 73, 5157-5167.
Petibois C., Piccinini M., Cestelli-Guidi M.A., Déléris G. and Marcelli A. (2009) Nature Phot. 3, 177
Della Ventura, G., Bellatreccia, F., Cesare, B., Harley, S., Piccinini, M. (2009) Lithos, accepted.
Wysoczanski, R., Tani, K. (2006) J. Volcan. Geoth. Res., 156, 302-314
Studio in-situ con tecniche spettroscopiche avanzate di film di silice mesoporosa ottenuti tramite tecnica sol-gel
No full textLa possibilità di realizzare materiali mesoporosi sotto forma di film sottili è particolarmente interessante, grazie alle possibilità di avere allo stesso tempo un sistema con caratteristiche completamente controllabili e con le proprietà intrinseche dei film sottili. Inoltre, una grande varietà di sistemi inorganici o ibridi può essere ottenuta facilmente con metodi basati sull’evaporazione e possono essere studiati approfonditamente tramite tecniche in-situ. Il controllo delle variabili chimiche e di trattamento permette anche di realizzare e riprodurre facilmente una grande varietà di matrici di oggetti con pori funzionalizzati. In questo lavoro di dottorato, tecniche sperimentali ben assestate, come lo scattering di raggi X ad angolo radente (SAXS) e la microscopia elettronica in trasmissione (TEM), sono state utilizzate per caratterizzare con precisione la simmetria strutturale della fase mesoporosa di film sottili e membrane sia di silice che di ibridi organici-inorganici ottenuti con tecnica sol-gel, attraverso l’autoassemblaggio indotto per evaporazione (EISA) e deposizione per immersione (dip-coating). Per la prima volta, la spettroscopia infrarossa a trasformata di Fourier (FTIR) risolta in tempo (rapid-scan) è stata usata in-situ per studiare la cinetica delle reazioni di policondensazione durante la formazione del film. La tecnica FTIR si è rivelata molto potente per comprendere in grande dettaglio i processi chimico-fisici che avvengono durante la formazione del film. È stata anche applicata in-situ simultaneamente alla tecnica SAXS per ottenere sia le informazioni strutturali che chimiche e ha permesso di stabilire l’importante ruolo dell’acqua e dell’etanolo nella formazione delle micelle e nell’organizzazione della mesostruttura nel tempo. Questi risultati ci hanno indotto a investigare in grande dettaglio i processi di evaporazione dell’acqua e dell’etanolo e come sono influenzati dalle condizioni ambientali (es. l’umidità), che giocano un ruolo fondamentale nelle proprietà finali dei film depositati. L’efficacia della tecnica infrarossa è stata confermata anche applicandola all’imaging FTIR risolto in tempo per studiare l’effetto “macchia di caffè” in un sistema puro solvente-soluto. Per ultimo, è stato dimostrato che è possibile realizzare matrici di oggetti mesoporosi funzionalizzati di dimensione e forma controllate, integrando la litografia deep X-ray e la scrittura dip-pen. È stato possibile controllare la qualità dell’intero processo produttivo tramite tecniche di caratterizzazione attualmente disponibili in una moderna facility di luce di sincrotrone. L’aver applicato con successo queste tecniche bottom-up e top-down permette di prevedere lo sviluppo di nuove tecnologie di fabbricazione di materiali mesoporosi con particolari funzionalità, come DNA nano-spotting e sistemi lab-on-a-chip.The possibility of processing mesoporous materials as thin films is especially interesting, due to the combined properties of a thoroughly tailored pore system and the inherent features of thin films. Moreover, a wide variety of inorganic or hybrid frameworks can be easily obtained by evaporation-based methods and thoroughly studied by in-situ techniques. The control of chemical and processing variables also permits the easy creation and reproduction of an amazing library of functional-pore arrays. In this doctorate work, well assessed experimental techniques, as small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM), have been used to characterize thoroughly the mesophase symmetry of silica and hybrid organic-inorganic films and membranes obtained by sol-gel processing, through evaporation-induced self-assembly (EISA) and dip-coating. For the first time, time-resolved rapid-scan Fourier-transform infrared (FTIR) spectroscopy has been used in-situ to study the kinetics of polycondensation reactions during film formation. The FTIR technique has shown to be very powerful to understand in great detail the chemical-physical processes that take place during film formation. It has been applied in-situ also simultaneously with SAXS, to have both the structural and chemical information and it has allowed to establish the important role of ethanol and water related to micelle formation and mesostructure organization with time. These results have led us to investigate in great detail the evaporation processes of water and ethanol and how they are influenced by the environmental conditions (i.e., relative humidity), which play a fundamental role in the final properties of the as-deposited mesoporous film. The power of the IR technique has been confirmed also by its application as time-resolved FTIR imaging to study the “coffee-stain” effect in a pure solvent-solute system. Finally, it has been shown that it is possible to fabricate mesoporous functionalized arrays with controlled size and shape by integrating deep X-ray lithography with dip-pen writing. It has been possible to control the quality of the whole production process by means of characterization techniques currently available in a modern synchrotron facility. The successful application of these bottom-up and top-down techniques allows to envisage new fabrication technologies of functional mesoporous materials for applications, such as DNA nano-spotting or lab-on-a-chip devices
Individual optimal frequency in whole-body vibration. Effect of protocol, joint angle, and fatiguing exercise
No full textCarlucci, F, Felici, F, Piccinini, A, Haxhi, J, and Sacchetti, M. Individual optimal frequency in whole-body vibration: effect of protocol, joint angle, and fatiguing exercise. J Strength Cond Res 30(12): 3503-3511, 2016-Recent studies have shown the importance of individualizing the vibration intervention to produce greater effects on the neuromuscular system in less time. The purpose of this study was to assess the individual optimal vibration frequency (OVF) corresponding to the highest muscle activation (RMSmax) during vibration at different frequencies, comparing different protocols. Twenty-nine university students underwent 3 continuous (C) and 2 random (R) different vibrating protocols, maintaining a squat position on a vibration platform. The C protocol lasted 50 seconds and involved the succession of ascending frequencies from 20 to 55 Hz, every 5 seconds. The same protocol was performed twice, having the knee angle at 120° (C) and 90° (C90), to assess the effect of joint angle and after a fatiguing squatting exercise (CF) to evaluate the influence of fatigue on OVF assessment. In the random protocols, vibration time was 20 seconds with a 2-minute (R2) and a 4-minute (R4) pauses between tested frequencies. Muscle activation and OVF values did not differ significantly in the C, R2, and R4 protocols. RMSmax was higher in C90 (p < 0.001) and in CF (p = 0.04) compared with the C protocol. Joint angle and fatiguing exercise had no effect on OVF. In conclusion, the shorter C protocol produced similar myoelectrical activity in the R2 and the R4 protocols, and therefore, it could be equally valid in identifying the OVF with considerable time efficiency. Knee joint angle and fatiguing exercise had an effect on surface electromyography response during vibration but did not affect OVF identification significantly
Borders of ius commune: ius commune at the borders, in D. Freda, M. Piccinini, H. Pihlajamäki, C.M. Valsecchi (a cura di), Borders of the Early Modern Ius Commune. England, Venice and Scandinavia, Routledge, London & New York 2025.
No full textIntroductio
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