http://http://dspace.unitus.it:80 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Thu, 20 Jun 2013 01:33:02 GMT 2013-06-20T01:33:02Z http://hdl.handle.net/2067/564 Title: Determinazione dei parametri elettromegnetici di materiali compositi e loro variazioni in funzione del contenuto idrico e di inquinanti Authors: Mattei, Elisabetta Abstract: Questa tesi è stata focalizzata sullo studio di tecniche elettromagnetiche applicate a sistemi solidi compositi e sul loro possibile impiego in campo ambientale. La tecnica principalmente usata è la Time Domain Reflectometry (TDR); altre tecniche parzialmente utilizzate sono state la tecnica LCR-meter, tecniche di misura conduttimetriche e GPR (Ground Penetrating Radar). Gli argomenti trattai sono riportati di seguito. È stato studiato l’apparato strumentale realizzando diversi tipi di sonda ed è stato studiato come le loro caratteristiche sia geometriche che elettriche influenzino il tipo di misura. Sono state eseguite misure di calibrazione su materiali aventi proprietà note (aria e acqua demineralizzata) per poter valutare i parametri fisici delle sonde come la lunghezza ‘elettrica’ e l’impedenza caratteristica della sonda. Le misure di calibrazione sono state effettuate con un nuovo metodo (metodo delle derivate) che consiste nell’utilizzare la derivata del segnale TDR: il confronto tra questo metodo con gli altri due noti in letteratura (il metodo delle tangenti e quello della funzione di trasferimento nel dominio della frequenza) ha dimostrato che l’utilizzo del metodo delle tangenti è affetto da errori sistematici nel caso di materiali dispersivi. Ciò comporta che le curve empiriche usate finora in letteratura per stimare il contenuto idrico dei suoli e ottenute con il metodo delle tangenti, debbano essere ritarate usando il nuovo metodo di calibrazione. Sono state eseguite misure di velocità e attenuazione del segnale elettromagnetico su materiali anidri ricchi di ossidi di ferro costituiti da palline di vetro (glass beads) e magnetite. Le misure sono state effettuate su tre diverse granulometrie e in funzione del contenuto volumetrico di magnetite. I dati sperimentali mostrano che la velocità di propagazione delle onde elettromagnetiche diminuisce all’aumentare del contenuto di magnetite ed è indipendente dalla granulometria. Il fattore di attenuazione mostra, come aspettato, un andamento crescente all’aumentare della percentuale volumetrica di magnetite per le granulometrie più grandi. Nel caso della granulometria più piccola, le incertezze sperimentali, probabilmente causate da problemi di riempimento della sonda hanno impedito l’individuazione di un andamento certo delle misurazioni. I risultati ottenuti sono stati confrontati con quelli provenienti da altre tecniche (LCR-meter e Network Analyzer) al fine di valutare l’attendibilità della misura dell’attenuazione ottenuta da TDR. Sono state effettuate misure di dispersione di inquinanti in colonna dalla misura della conducibilità elettrica del mezzo tramite TDR. In particolare, l’analisi è stata centrata sulle acque di vegetazione visto l’interesse che queste sostanze destano nell’ambito delle scienze ambientali e agrarie. Sono stati realizzati esperimenti di prova al fine di valutare la condizione in cui si potesse monitorare la propagazione del refluo. Le misure di dispersione sono state eseguite su mezzi diversi per stabilire i tempi di propagazione in funzione della matrice solida usata. La conducibilità è stata correlata tramite curve di calibrazione al contenuto volumetrico e, quindi, alla concentrazione di refluo: l’andamento della concentrazione in funzione del tempo può essere confrontato con le curve di dispersione note in letteratura e dal confronto è possibile ricavare i parametri di propagazione nel mezzo. È stata realizzata una campagna di misure TDR e GPR (Georadar) su un sito sperimentale. Il sito è costituito da una vasca (4m x 7m), isolata dal terreno circostante tramite un telo impermeabile e riempita con sabbia. La vasca è stata saturata con acqua progressivamente dal basso in modo da simulare la risalita di una falda. Per ogni livello raggiunto dal liquido, sono state effettuate, simultaneamente, misure TDR e GPR. Le misure TDR sono state effettuate sia con una sonda orizzontale multilivello fissa seppellita al bordo della vasca, sia con sonde verticali mobili (da 10 e da 20 cm) da inserire in superficie. I parametri elettromagnetici del sito ottenuti dalle misure TDR sono stati confrontati con le forme d’onda del GPR al fine di trovare una correlazione tra le due tecniche di misura.; This thesis is devoted to the electromagnetic techniques, the Time Domain Reflectometry (TDR) in particular, applied to the study of composite systems and to their possible employment in environmental sciences. The TDR, the LCR-meter, GPR (Ground Penetrating Radar) and conductimeter are the technique used in this study. The thesis develops as follows: The TDR experimental device has been used to determine the geometric and electrical features of several probes via calibration measurements, carried out on materials with known electromagnetic properties (air and demineralized water). A new calibration method has been introduced (the derivatives method) and the comparison between this method and the others two used in literature (the tangents method and the transfer function method) demonstrated that the tangents method is affected by systematic errors when it is applied to a dispersive medium. So, the empirical curves used in literature to estimate the soil water content and obtained with the tangents method, should be re-calibrated using the new method. Anhydrous mixtures of glass beads and magnetite have been analyzed in order to estimate the electromagnetic velocity and the attenuation factor. The measurements have been carried out on three grains size ranges for different magnetite volumetric contents. The data have shown that the electromagnetic wave propagation velocities decrease with the increase of the magnetite content and are independent on the grains sizes. For the bigger grains size range, the attenuation factor increases with the volumetric percentage of magnetite, while for the smaller one, the experimental uncertainties, probably due to filling problems, prevent the accurate determination of the attenuation factor. To determine the reliability of the TDR measurements, the attenuation values have been compared with those obtained by other techniques (LCR-meter and Network Analyzer). Dispersion of olive waste waters has been studied by measuring the electrical conductivity by TDR. Some preliminary experiments have been realized to test the possibility of monitoring the propagation of the olive waste water. Three different media have been chosen to establish the influence of the solid matrix on the dispersion phenomena. The conductivity has been correlated to the volumetric content using calibration curves: the concentration versus time has been compared with the dispersion curves of specific theoretical models of literature and the propagation parameters have been estimated by the experimental data fitting. TDR and GPR measurements have been carried out on a test-site. The test site consists of a pit filled with gravel and sand in which a pipe system for water inflow is buried. The data were collected under different water charge conditions and the water level was monitored by piezometers. TDR measurements were performed at various depths using a multilevel probe system and using vertical three wire probes. GPR measurements were performed with a system equipped with 250 MHz and 500 MHz antennas. The electromagnetic parameters obtained by TDR have been compared with the GPR data to find a correlation between water content provided by the two techniques. Description: Dottorato di ricerca in Scienze ambientali Tue, 07 Oct 2008 22:00:00 GMT http://hdl.handle.net/2067/564 2008-10-07T22:00:00Z http://hdl.handle.net/2067/1323 Title: I gialli di piombo, stagno, antimonio: le opere di Poussin a Saraceni Authors: Pelosi, Claudia; Santamaria, Ulderico; Morresi, Fabio; Agresti, Giorgia; De Santis, Alberto; Mattei, Elisabetta Abstract: In order to characterize the yellow pigments utilized by Carlo Saraceni in The Martyrdom St Erasmus (1612-14), Cathedral of Gaeta (Lt),and by Nicolas Poussin in The Gedeone’s Victory over Madianiti (1623-26) and The Martyrdom St Erasmus both finding at Vatican’s Museum had been applied: micro-Raman spectroscopy, fluorescence X, SEM with micro-analysis EDS, observations at optic-mineralogical microscope and spectro colorimetric analysis; some of these methods were applied on artworks directly, others by micro-pattern taken over paintings. The same investigations had been applied also over others patterns of yellow pigments having the same typology of materials employed by painters and that had been retrieved by commerce from the firms of Kremer and Zecchi. Fri, 31 Aug 2007 22:00:00 GMT http://hdl.handle.net/2067/1323 2007-08-31T22:00:00Z http://hdl.handle.net/2067/1233 Title: Artificial yellow pigments: production and characterization through spectroscopic methods of analysis Authors: Pelosi, Claudia; Agresti, Giorgia; Santamaria, Ulderico; Mattei, Elisabetta Abstract: Artificial yellow pigments (lead-tin yellow type I and type II, lead antimonate yellow and lead-tin-antimony yellow) have been produced, starting from various recipes and from pure chemicals, in different experimental conditions. The products were analysed using micro-Raman spectroscopy. Differences in stoichiometric ratios, in melting temperatures and in crucible typologies were examined. Other analytical techniques were required to characterize the stoichiometric ratios of the obtained products (X-ray diffraction, scanning electron microscopy with energy dispersive spectroscopy and differential thermal analysis).The results are analysed and discussed in terms of correlations among chemical composition, melting conditions and colour hue. Thu, 31 Dec 2009 23:00:00 GMT http://hdl.handle.net/2067/1233 2009-12-31T23:00:00Z http://hdl.handle.net/2067/1325 Title: Raman spectroscopic analysis of azurite blackening Authors: Mattei, Elisabetta; De Vivo, Giulia; De Santis, Alberto; Gaetani, Carolina; Pelosi, Claudia; Santamaria, Ulderico Abstract: Azurite is a basic copper carbonate pigment largely employed in painting realization. The areas painted with azurite are easily alterable and are often less resistant than the other parts of artworks. The azurite alteration in a black pigment, the copper oxide (tenorite), has been studied by micro-Raman spectroscopy. The blackening can be due to thermal or chemical alterations: in the second case the alterations being due to the presence of alkaline conditions. Laser-induced degradation of azurite has been studied as a function of the grain size. The results show that the temperature of the grains decreases as the size increases, and azurite degrades into tenorite only below the critical value of 25 μm. To study the chemical alteration of azurite, the pigment has been applied on the plaster of terracotta samples and analyzed at different pH values by micro-Raman spectroscopy. As opposed to most part of the analytical techniques, it can detect the presence of both azurite and tenorite molecules in the same micro areas, and provides a valuable tool to determine azurite degradation. Thu, 31 Jan 2008 23:00:00 GMT http://hdl.handle.net/2067/1325 2008-01-31T23:00:00Z http://hdl.handle.net/2067/1324 Title: Micro-Raman and stratigraphic studies of the paintings on the ‘Cembalo’ model musical instrument (A.D. 1650) and laser-induced degradation of the detected pigments. Authors: De Santis, Alberto; Mattei, Elisabetta; Pelosi, Claudia Abstract: Micro-fragments of the painted part of the ‘Cembalo’ model by Michele Todini (1625–1689) are investigated.The technique used for painting the terracotta base was studied via the stratigraphic analyses. No background layer of inorganic materials, e.g. gypsum, was found. To prevent absorption effects due to the terracotta porosity, a very thin layer of proteinaceous material was probably used. The micro-Raman analyses have revealed the use of pigments currently used in the post-Renaissance period (lead white,indigo, yellow of iron hydroxide, gypsum, hematite and carbon black) mixed with a pigment, the Prussian blue, discovered in A.D. 1704. This raises the authenticity problem of the work of art, a problem analysed and discussed in presenting the history of the work of art, and after the pigment study. The presence of degraded lead white is recognized via the laser-induced degradation of the irradiated material. The possibility of a restoring action of the painted parts, as opposite to the non-originality of the work, is considered and discussed. Since most part of the investigated pigments shows laser-induced effects, a careful study of this phenomenon is performed by using the modern counterparts of the ancient pigments. For different laser powers, the temperatures of the investigated zones have been obtained via the detailed balance principle and connected to the laser-induced degradation effects. Sun, 30 Sep 2007 22:00:00 GMT http://hdl.handle.net/2067/1324 2007-09-30T22:00:00Z http://hdl.handle.net/2067/1326 Title: Lo stendardo processionale della Confraternita del Santissimo Sacramento di Sutri Authors: Latini, Elena; Pelosi, Claudia; De Santis, Alberto; Mattei, Elisabetta; Capriotti, Giorgio Abstract: Lo stendardo processionale della Confraternita del Santissimo Sacramento di Sutri (VT), attualmente conservato presso il Museo Civico del Patrimonium , restaurato presso il Laboratorio Provinciale di Restauro di Viterbo (dal 2004 al 2006), è stato l’oggetto di un progetto di restauro coadiuvato da un team di specialisti di diverse discipline rivolti alla comprensione dei vari aspetti conservativi dell’opera in esame . L’opera è attribuita ad Eugenio Agneni (Sutri 1816-Frascati 1879), artista di notevole rilevanza storica, le cui gesta, malgrado si tratti di epoca assai recente, rimangono sepolte tra le pieghe delle memorie storiche del Risorgimento. Lo stendardo, non datato, è attribuito al pittore come opera giovanile. E’ una tela dipinta ad olio e raffigura sul verso L’Adorazione del Santissimo Sacramento e sul recto San Bonaventura presenta la Confraternita alla Vergine e al Bambino con due confratelli con l’abito tipico, ancora in uso, e sullo sfondo la cattedrale di Sutri con accanto delle montagne che si suppone siano i vicini monti Cimini. Nel 2004, all’inizio del restauro, lo stendardo appariva ad un buon livello qualitativo, ma carico di depositi superficiali e con numerose sovrapposizioni di interventi di restauri precedenti volti a salvaguardarne sia l’opera che la funzione processionale. Si vogliono qui delineare i risultati dello studio dell’autore, dello stendardo e della storia conservativa, attraverso lo studio dei documenti di archivio, con le analisi chimiche e diagnostiche di supporto all’intervento di restauro. Sun, 30 Sep 2007 22:00:00 GMT http://hdl.handle.net/2067/1326 2007-09-30T22:00:00Z http://hdl.handle.net/2067/1329 Title: Production and characterisation of lead, tin and antimony based yellow pigments Authors: Pelosi, Claudia; Santamaria, Ulderico; Agresti, Giorgia; Mattei, Elisabetta; De Santis, Alberto Abstract: This study deals with the preparation of yellow pigments (lead-tin yellow type I and II, lead antimoniate yellow and lead-tin-antimony yellow), which are affected by terminological confusion in the historical references. Through the centuries, yellows of different compositions, based on lead, tin and antimony, have been used either as agents that turn glasses, glazes and majolica opaque or as paint-pigments. Some types of yellow pigments were described in written sources. These sources are very hard to discover because production methods and formulas of artistic compounds were handed down to new generations in oral way. Sometimes, they were collected in secret books of pigments. In addition, artists and writers, during the utilization and production of lead-tin-antimony yellows, introduced some changes both in recipes and terminologies. All this produced great confusion in the nomenclature that changes the country tradition and, sometimes, for the writer’s inaccuracies. By analyzing the various recipes concerning lead-tin-antimony yellows, it was possible to reconstruct the original production methods of these pigments. We produced lead-tin yellow type I (Pb2SnO4) and lead-tin yellow type II (PbSnO3 or PbSn1-x SixO3) following the indication of the recipes 272 and 273 of the fifteenth century Bolognese Manuscript, lead antimonate yellow, called Napoli yellow, according to the treatises written by Piccolpasso, Passeri and Mariano from Pesaro, and lead-tin-antimony yellow from the Darduin, Mariani da Pesaro and other recipes authors. The production of lead-tin-antimony based yellow pigments was obtained by pure chemicals oxides (PbO, Pb3O4, SnO2 and Sb2O3). In synthesizing the yellow pigments, the effects produced by changes in stoichiometric ratios, in melting temperatures and in the crucible typologies were tested. The obtained products were characterized by SEM-EDS, XRD and micro-Raman analyses. To evaluate colour changes due to different melting temperatures and stoichiometric ratios, the colour measurements were taken in CIE 1931 and CIE 1976 coordinates. The results are analysed and discussed in terms of correlations among chemical compositions, melting conditions and colour hue. The study of these pigments, produced in laboratory with the ancient procedure, is also useful for investigations on similar materials used in the works of art. Indeed, it is very probable that the artists chose their painting materials by selecting not only the colour hue of the pigments but also the production method. Therefore, it is important to state a correlation between chemical compositions, ancient production methods, and the final colour hue of the produced yellow pigments. Mon, 31 Dec 2007 23:00:00 GMT http://hdl.handle.net/2067/1329 2007-12-31T23:00:00Z http://hdl.handle.net/2067/1625 Title: Study of decorated pottery fragments by means of micro-Raman and other techniques Authors: Pelosi, Claudia; Montini, Ilaria; Mattei, Elisabetta; Gaudenzi Asinelli, Mainardo; De Santis, Alberto Abstract: The aim of this work was to apply several spectroscopic methods of analysis to study the decorated pottery fragments found in the excavations of the Medici Villa of Cafaggiolo, near Florence, and of the roman-medieval site of Ferento, near Viterbo. The results of the analysis performed on the samples coming from these sites have been compared with thin sections mineralogical examination of the same samples. The main objective of the analysis, performed in the pottery fragments of two site of central Italy, has been to obtain information about the productive processes, the firing temperatures and the materials used in medieval and Renaissance period. Further purposes were to enrich the knowledge and the databases of pottery materials and techniques, to study the evolutions of the productive processes through the history and eventually to try to identify the elements that characterize the two examined Italian productions. Micro-Raman technique doesn’t need a pre-treatment of the samples under test; moreover micro-Raman is a non-destructive molecular method of analysis recently widely applied in the field of cultural heritage. In this work the results of micro-Raman analyses of Cafaggiolo pottery are related. Moreover some mineralogical studies on the Cafaggiolo and Ferento potteries are proposed. The Cafaggiolo potteries were also examined by means of quantitative X-Ray Fluorescence analysis and X-Ray diffraction. Sun, 31 May 2009 22:00:00 GMT http://hdl.handle.net/2067/1625 2009-05-31T22:00:00Z http://hdl.handle.net/2067/1626 Title: L’indagine diagnostica per il restauro: il caso del modello ligneo della Chiesa di S. Maria della Consolazione in Todi Authors: De Santis, Alberto; Lo Monaco, Angela; Mattei, Elisabetta; Pelosi, Claudia; Santancini, Marco Abstract: The wooden polychrome Model of the Church of S. Maria della Consolazione in Todi is an handmade article whose author and historical events are not completely known except a wide reference to the construction period of the church (1508-1607). During the restoration, carried out in the first half of the year 2007, some diagnostic analyses were performed in order to study and characterize the materials, the techniques and the conservation state of the model and so to provide a valid help to the restoration itself. The pigments, binders, restoration materials and the different wooden parts were examined. The samples were taken off during the disassembly of the model and they were analyzed by means of a polarizing microscope. The chemical analyses were carried out by means of micro-Raman spectrometer and by means of FTIR and micro-FTIR spectrophotometry. The cross, radial and tangential thin sections of the wooden samples were examined under an optical microscope. Mon, 31 Dec 2007 23:00:00 GMT http://hdl.handle.net/2067/1626 2007-12-31T23:00:00Z http://hdl.handle.net/2067/1758 Title: Caratterizzazione dei pigmenti in alcune miniature medievali tramite tecniche diagnostiche non invasive Authors: Ardagna, Vincenzo; Pelosi, Claudia; De Santis, Alberto; Mattei, Elisabetta Sun, 31 Dec 2006 23:00:00 GMT http://hdl.handle.net/2067/1758 2006-12-31T23:00:00Z http://hdl.handle.net/2067/1749 Title: Analisi stratigrafiche e micro Raman. Modello del Cembalo Todini Authors: De Santis, Alberto; Mattei, Elisabetta; Pelosi, Claudia Sun, 31 Dec 2006 23:00:00 GMT http://hdl.handle.net/2067/1749 2006-12-31T23:00:00Z http://hdl.handle.net/2067/2238 Title: A microRaman and internal microstratigraphic study of ceramic sherds from the kilns of the Medici castle at Cafaggiolo Authors: De Santis, Alberto; Mattei, Elisabetta; Montini, Ilaria; Pelosi, Claudia Abstract: Nine representative sherds from the old (14th–16th century) kilns at the Castle of Cafaggiolo in Tuscany have been analysed by means of internal microstratigraphic analyses and micro-Raman spectroscopy and classified as follows: six engobed and glazed fragments, of which three are covered with an opaque white, decorated layer, one is marbleized, and two are engobed. The surface of the two engobed sherds, fragments of unfinished products, indicates that at least two firing processes were used. Two samples show characteristics of Byzantine pottery, and three of them can be classified as Islamic ware or maiolica, whilst the other one displays intermediate characteristics. The variety of ceramic wares indicates the presence of craftsmen with differing expertise, and suggests that part of their work was dedicated to experimentation on new ceramic production techniques. Sat, 31 Dec 2011 23:00:00 GMT http://hdl.handle.net/2067/2238 2011-12-31T23:00:00Z