The ways of the lustre: looking for the tunisian connection

Recent excavations at the Fatimid and Zirid site of Sabra al-Mansuriya near Kairouan (Tunisia) provide the first evidence of lustreware production in medieval Ifriqiya, in the 10th–11th centuries AD. As the Fatimid dynasty moved from Ifriqiya to Egypt to establish its capital in Fustat (Cairo), technological connections with the Egyptian lustreware could be expected. Tunisian lustreware may also be the link in the transmission of the technique towards Muslim Spain. It represents a new piece of the puzzle of understanding the diffusion of lustre technology from the East to the West of the Mediterranean. The composition and microstructure of the bodies and glazes, and the micro- and nano-structure of the lustre layer are compared in a preliminary approach to the technological relationships between Tunisian, Egyptian, and Spanish lustrewares.Peer ReviewedPostprint (published version

L'angolo dell’intervista: uno spazio per testimonianze di sofferenza, di speranza e di solidarietà

In questo numero, Luca Guglielminetti intervista Antonio Iosa a proposito de Il libro dell’incontro. Vittime e responsabili della lotta armata a confronto, curato da Guido Bertagna, Adolfo Ceretti e Claudia Mazzucato, pubblicato presso Il Saggiatore nel 2015

Materials Surface Science Applied to the Investigation of Cultural Heritage Artefacts

This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/International audienceThe skill of ancient artisans manufacturing artistic or everyday artworks surprises the modern material scientists. We show, through the study of archaeological pieces, how laboratory research instruments use enlightens the fabrication processes of unique items at antic periods. The specificity of surface science research favouring non-invasive means for investigations on museum objects is emphasised. The examples concern: Nanostructured layers on ceramic surface to obtain the so-called lustre effect, invented by ancient Islam potters; Intentional coloration of metallic objects by chemical patination, attested in Egypt on 2nd millenary BC and still applied by Japanese artisans; The history of gilding objects: leaf gilding, mercury gilding, and other processes; The Fresco technique, a perennial wall painting, known by ancient Roman and propagated through centuries. The examples open new fields belonging to the modern materials science, to understand the mechanism involved in processes with the constraint that one does not know all the fabrication steps

L'agito aggressivo: la gestione della situazione di crisi

L’aggressività, in quanto condotta diretta contro conspecifici sotto forma di agiti distruttivi, si manifesta in molteplici contesti, con rilevanti ripercussioni sul versante del contenimento dell’attore violento in situazioni di crisi. Impiegando il paradigma bidimensionale proposto da Geen (1990) - che teorizza l’esistenza di una duplice forma di aggressività, in base alla prevalenza della componente emotiva o di quella cognitiva del soggetto - si intende dimostrare la necessità di predisporre specifiche tecniche di approccio all’agito violento, in ragione del differente grado di incidenza sul medesimo degli elementi di autoregolazione cognitiva da parte dell’attore. Il modello criminologico proposto dallo studioso statunitense Athens, e recentemente ripreso da Ceretti e Natali (2009), si rivela un efficace strumento metodologico per la comprensione dell’attore violento e del significato del suo agire, al fine di favorire l’elaborazione di adeguati protocolli operativi

New Leaf Gilding Alloys: Physico-Chemistry, Colour, Mechanical Behavior

International audienceIn the frame of a systematic investigation on leaf gilding history and processes, in a research program intending to propose gold leaf alloys specially devoted to restoration, new gold alloys containing low concentration additions of In or Pd were designed and leaves were elaborated in collaboration with the goldbeater Dauvet. The influence of those elements on the colour change induced by alloying was obtained by colorimetry. The microstructural and metallurgical properties of the alloys were studied by scanning electron microscopy (SEM). The foils and leaves were characterized at the different manufacturing steps by EBSD (Backscattered Electron Diffraction), in order to evaluate the effect of the fabrication process on the microstructure and crystallographic texture. Surface segregation of the alloying element, influencing surface colour, was sometimes evidenced and discussed. The mechanical properties of the foils or leaves were measured by micro-and nano-indentation. The obtained properties and behaviour of the new alloys were compared with those of the leaves currently used for leaf gilding. The results conducted the beating company to consider developing new gold leaves production range(s) devoted specially for restoration application. As a result of the present investigation, new manufacturing and gilding procedures have been proposed

Biotreatment of cr(VI)-containing wastewater mediated by indigenous bacteria

Indigenous Pseudomonas veronii 2E, Klebsiella oxytoca P2 and Klebsiella ornithinolityca 1P were tested as catalysts for the transformation of Cr(VI) to Cr(III) for Cr(VI)-containing wastewater biotreatments. The Cr(VI) biotransformation was assayed during bacterial growth and by using pre-grown quiescent cells. Proof of the unsuitability of a biotreatment based on Cr(VI)-reduction during bacterial growth was found: the reduction rate and the maximum Cr(VI) concentration able to be reduced were too low. On the other hand, high density suspensions of pre-grown quiescent cells presented the highest reduction rates, especially in the presence of an electron donor. The most efficient strain for Cr(VI) removal was Pseudomonas veronii 2E. Optimal pH and temperature for the biotransformation process resulted 7 and 32ºC respectively. The maximum initial reduction rate obtained in these conditions was 0.49 mg Cr(VI) h-1 g cell dry weight-1 (9.4 µmol Cr(VI) h-1 g cell dry weight-1). Proof of the feasibility and efficiency of this technology is provided by using in calcium alginate immobilized P. veronii 2E cells for the treatment of a real Cr(VI)-containing industrial wastewater.Fil: Alessandrello, Mauricio. Universidad Nacional de General Sarmiento. Instituto de Ciencias. Área de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Vullo, Diana Lia. Universidad Nacional de General Sarmiento. Instituto de Ciencias. Área de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Gilding for Matter Decoration and Sublimation. A Brief History of the Artisanal Technical Know-how

IJCS it is an open access journal. All content is freely available without charge to any user or his/her institutionInternational audienceThe process used to decorate art objects with thinner and thinner gold coatings varied during centuries. Foil or leaf metal gilding technology was complemented around the beginning of the Christian era by mercury gilding. Simultaneously was developed in some geographic areas the surface depletion process for gilded copper/silver alloys. This paper is motivated by the recent publication by the authors of a didactic opus devoted to the description and the discussion of the technical history of the various gilding procedures, based on the study by modern investigation techniques of a number of gilded museum objects. Through examples from laboratory studies on museum objects, the main evolution steps of gold application are described. A recent mechanical modelling work about gold leaf forming by beating is reported. The different coating processes are discussed, depending on the substrate nature and surface treatment before gilding. It includes high temperature firing for mercury gilding, or powder gilding, e.g. on Middle-Age Syria glass. The paper ends with a listing of the research perspectives open for the presently poorly developed study of the adhesion mechanisms between gold leaf and its substrate. It discusses the important issue of gold-metal interdiffusion during metal gilding processes involving a high temperature step

Multi-layered Scaffolds Production via Fused Deposition Modeling (FDM) Using an Open Source 3D Printer: Process Parameters Optimization for Dimensional Accuracy and Design Reproducibility

Abstract One of the most applied strategies in tissue engineering consists in the development of 3D porous scaffolds with similar composition to the specific tissue. In fact, the microstructure of the scaffolds influences the final structure of the in growing tissue. In this study, multi-layered PCL scaffolds were produced with modified Fab@home FDM printer in order to analyze the influence of the extrusion technology (filament or powder extrusion head) and of the process parameters on the deposited material. In particular, dimensions and uniformity of both deposited filament and grid of the scaffolds were analyzed to understand the influence of the process parameters so as to optimize the FDM production technology

Tools for the development of a benthic quality index for Italian lakes

In this paper, we propose a methodology to develop a benthic quality index useful for Italian lakes. The existing data about benthic macroinvertebrates of the Italian lakes were collected over a period of 50 years, but only a few lakes such as the Maggiore and the Mergozzo have been intensely studied. Some large lakes such as Lake Como are still almost uninvestigated. In total, 570 benthic macroinvertebrate taxa were identified; of which 373 belong to Chironomidae and 85 to Oligochaeta. With the aim of relating environmental variables with macrobenthos assemblages, we carried out a canonical correlation analysis (CANON) using a database that included 1060 sampling points. Both environmental (13 variables describing morphometry and hydrochemistry) and biological data (57 taxa) were available, but only taxa present in at least 10 samples were selected for data analysis. Three canonical variates were ecologically significant. The first one was correlated with conductivity, pH and alkalinity and accounted for 20% of the total variation. The second one was positively correlated with total phosphorus and N-NH4, and inversely with dissolved oxygen, and accounted for 18% of the total variation. The third one showed a direct correlation with maximum lake depth and volume and an inverse correlation with water temperature, and accounted for 17% of the total variation. A Trophic Status Index (TSI), based on the table 11 of the Italian Law 152/99 (without including chlorophyll), was calculated by ranking percent oxygen saturation, transparency and total phosphorus. TSI was used to test a Benthic Quality Index for Italian Lakes (BQIL) which is proposed in the present paper. The algorithm considered three steps. First, the means of three variables were calculated: percent oxygen saturation, transparency and total phosphorus weighted by the taxa abundances. These values are interpreted as optimum for each taxon and used to assign an indicator weight (BQIW). Second, the mean of these three variables was calculated for each taxon (mean BQIW). Third, the mean BQIW was multiplied by taxa abundance and divided by the total number of specimens present at each site for which the BQIL was obtained. Using a regression between BQIL and TSI values, lake sites were assigned to 5 quality classes as required by the Italian Law 152/99 and the WFD 2000/60/CE. This assignment must be considered as tentative, because different lake types should be considered separately to develop an index. At present the lack of information from different lake typologies hinders the development of a more sophisticated index such as the French Lake Biotic Index (LBI).Studio iniziale per la messa a punto di una metrica (indice di qualit?) delle acque dei laghi Italiani con l\u27utilizzo del macrobenthos per l\u27assegnazione dei suddetti laghi a 5 categorie di qualit?, cos? come previsto dalla Direttiva Quadro sulle Acque (WFD 2000/60/CE). Sono presentati dati abiotici (parametri considerati dalla Legge 152/99) e biotici che sono risultati correlati all\u27idrochimica lacustre. Nel lavoro si evidenziano carenze sulla presenza di alcune tipologie lacustri presenti in Italia