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[Display omitted] • Combined non-destructive analytical approach using portable instrumentation • Complementary techniques and multivariate analysis allow characterization of pigments • Improved knowledge on pigments production, sourcing and use in 27 BC – 193 AD Rome Polychrome painted plasters from a suburban villa of Imperial epoch were recovered during the 1930s, and are currently exhibited in the galleries underneath the St. John in Lateran Church, Rome. As wall paintings from the Rome area are a rare find, and as the fragments were never subjected to conservation treatments, it was chosen to non-invasively characterize 113 coloured areas, representative of colours and decorative systems. The chemical and mineralogical information collected from this measurement campaign were interpreted in the light of archaeological context (i.e. the high status of the family who owned the villa , the different renovation works that affected it, the identification of decorative systems linked to such works), as well as of published data from contemporary wall paintings in the Rome area. A multi-analytical, non-destructive characterization of the painted surfaces was carried out in situ by means of portable Raman spectroscopy (pRS) and X-ray fluorescence (pXRF), in the framework of a wider project concerning the study of raw materials and paintings of archaeological interest. The combination of pXRF and pRS allowed to characterize the whole palette, as well as to discriminate among different pigments sharing the same key element, and to identify degradation issues. In this context, the use of principal component analysis gave an important contribution to the interpretation of data ant to the individuation and characterization of pigments such as ochres, green earths, lead based pigments, Egyptian blue, cinnabar, Tyrian purple. Calcium and magnesium carbonates are present, as expected, in the plaster, and are often associated with their sulphates and nitrates, and Ca-oxalates indicating degradation. Lead white and bone white have been used. Some peculiar yellow pigments have been identified, such as realgar/pararealgar and Naples' yellow, in addition to ochres. Hematite, minium and cinnabar were all identified, alone or in mixtures. The presence of the precious dye Tyrian purple is very likely, but could not be confirmed univocally. Green earths and complex mixtures of iron and copper compounds were detected. Egyptian blue was used, highlighting different production processes for this artificial glassy material. For the blacks, we hypothesize the use of carbon-based pigments. The obtained data confirms the general palette used by Roman painters, and sheds new light on the materials used in the Lateran area across two centuries, including their provenance and manufacturing. It appears that different earths and ochres were used diachronically, and that the owners could afford very expensive pigments, such as cinnabar and Tyrian purple. [ABSTRACT FROM AUTHOR]

• An artificial neural network for archaeometric studies has been created to facilitate provenance attribution of archaeological ceramics. • The ANN has been trained by clays mixings mathematically constructed based on a reference chemical database of Sicilian sediments. • Test has been performed by querying the ANN with compositional data of pottery found in archaeological sites. Up to 88% correct attribution has been verified. • Merits of NN have been highlighted, comparing the extent of successfully provisional attribution with results achievable by using classical multivariate statistical method. An artificial neural network (ANN) for archaeometric studies was created to facilitate provenance attribution of archaeological ceramics. A multilayer perceptron model (MLP) was applied to construct the network, including only one hidden layer. Moreover, correction parameters based on historical and archaeological evidences were applied to Bayesian probability factor. The ANN was trained by using clays mixings mathematically constructed based on a reference chemical database of Sicilian sediments. The clay mixing takes in consideration compositional variability within the same geological site and the extent of the ceramic manufacture processes. Test was performed by querying the ANN with compositional data of ceramics found in archaeological sites coherent with clays sampling areas. Up to 88% correct attribution was verified, with good correspondence between geological and archaeological contexts. Finally, merits of ANN were highlighted by comparing the extent of successfully provisional attribution with classical statistical methods (PCA and LDA). [ABSTRACT FROM AUTHOR]

The accuracy and spatial resolution of full-field deformation measurements performed through digital image correlation are greatly affected by the frequency content of the speckle pattern, which can be effectively controlled using particles with well-defined and consistent shape, size and spacing. This paper introduces a novel toner-transfer technique to impress a well-defined and repeatable speckle pattern on plane and curved surfaces of metallic and cement composite specimens. The speckle pattern is numerically designed, printed on paper using a standard laser printer, and transferred onto the measurement surface via a thermo-mechanical process. The tuning procedure to compensate for the difference between designed and toner-transferred actual speckle size is presented. Based on this evidence, the applicability of the technique is discussed with respect to surface material, dimensions and geometry. Proof of concept of the proposed toner-transfer technique is then demonstrated for the case of a quenched and partitioned welded steel plate subjected to uniaxial tensile loading, and for an aluminum plate exposed to temperatures up to 70% of the melting point of aluminum and past the melting point of typical printer toner powder. [ABSTRACT FROM AUTHOR]

Abstract: Even though digital image correlation (DIC) is a widely used optical full field measurement method, it still needs further performance investigations, when it comes to dynamic conditions. Dealing with a moving target, causes a motion effect (i.e. blurring) on the acquired images. This factor is an important source of uncertainty that needs to be quantified. Therefore, the present study aims to perform a systematic uncertainty assessment of DIC method in general dynamic applications. The study focuses on 2D DIC. In the case of 3D DIC similar problems will arise and therefore, a complete understanding of two dimensional conditions will be of great help to further studies which deal with 3D conditions. The whole work can be divided in to two parts. In the first part, a method to simulate the motion effect on a reference image is proposed to be applied. This method allows simulating the acquired images in a real dynamic test and estimating the measurement uncertainty caused by the motion effect. Using this technique, the uncertainty of DIC measurement is estimated. The second part of the study aimed to validate the simulation technique. Therefore, several tests are conducted by imposing harmonic motion to a target, in different frequencies and amplitudes. The results show good agreement between the experiments and the simulations, proving the introduced technique to be an effective method for motion induced uncertainty estimation. [Copyright &y& Elsevier]

This study provides experimental insights into the optimization of alkali-activated materials (AAMs) carried out in situ at the restoration site of Monreale Cathedral, Italy. Volcanic ash from Mt. Etna volcano (Italy) was used as a precursor to obtain AAMs. Standard and modified pastes with a small amount of slaked lime paste were compared in terms of setting time, rheology, mineralogy, chemical morphology, and mechanical performance. The modified pastes exhibited a faster setting time, superior mechanical strength and rheological properties. Mineralogically, no difference was observed between the two pastes for the small amount of slaked lime paste added very close to the detectable limit (<2 wt%). Moreover, its addition causes slight differences in the morphology of the gel without changing the chemical composition of the Na 2 O–CaO–Al 2 O 3 –SiO 2 –H 2 O ((N,C)-A-S-H)) type. The results obtained may be useful for the development and optimization of building materials (especially for restoration purposes) where appropriate physico-mechanical performance is required. [Display omitted] [ABSTRACT FROM AUTHOR]

In the present study, porous inorganic polymers were synthetized by alkaline activation of volcanic ash and ' ghiara' paleosoil using Al swarf and Al commercial powder as pore inducing agent. The Alkali Activated Foams (AAFs) were characterized in terms of mineralogy, macro- and microstructure, by synchrotron X-ray diffraction, electron microscopy, infrared spectroscopy, and X-ray computed microtomography. The obtained porous matrices show different microstructures; the size and extent of the pores vary according to the type, size and amount of the foaming agent and to the viscosity of the pastes. Addition of Al swarf to the volcanic ash based slurry generates expansion of the paste, whereas ghiara based one do not expand due to a lower viscosity of the slurry. Moreover, results indicate that the Al addition procedure during the synthesis affects the pore characteristics: Al powder added directly to the volcanic ash-based slurry triggers an incipient pore nucleation, whereas AAFs prepared adding Al powder to the solid mix do not develop an extended pore network. Results of this research show that porosity can be efficiently tailored in volcanic based AAFs by regulating the amount and type of Al. [ABSTRACT FROM AUTHOR]

The structural properties of geopolymers based on locally available volcanic feedstocks were here investigated in the optics of the development of sustainable non-structural building materials. Geopolymer binders and mortars based on two volcanic pyroclastic residues from Mt. Etna (ejected ash and a paleosoil, named "ghiara") were studied to assess the effects of natural weathering. The strength and durability of the resultant products were examined before and after six months of outdoor exposure by comparing ultrasound pulse velocity (UPV), specific weight, Brazilian Disk test (BD) and Digital Image Correlation (DIC) together with Dynamic Vapour Sorption (DVS) results. DVS data were also compared to those of pure salts (e.g. sulphates and carbonates) commonly occurring in geopolymers as efflorescences. The results obtained on unexposed and exposed samples and the relationship between the moisture transportation, efflorescence development, and structure degradation have shown a better response of the volcanic ash-based geopolymers to weathering in the hot summer Mediterranean climate zone than ghiara-based products. The latter are more affected by exposure conditions as revealed by the decrease of UPV, the influence of efflorescences on moisture adsorption-desorption curves and the consequent worsening of mechanical performances. The correlation between UPV and DVS applied for the first time to the study of volcanic precursors-based geopolymers exposed to natural weathering has proven to be an effective and useful tool for assessing the durability of materials. [ABSTRACT FROM AUTHOR]

A combination of conventional and un-conventional methods is here used to assess the physical-mechanical properties of some alkaline activated pastes and mortars. The latter were purposely synthetized by using Etna ashes as precursor, whose suitability in the alkaline activation process has been ascertained by previous studies. Additionally, the potential reuse of the huge quantities of pyroclastic deposits released into the atmosphere during explosive volcanic eruptions represents an ambitious challenge for the local communities, other than being part of the "Ecological transition" topic promoted by the European Community. The physical-mechanical characterization of the experimental materials has been carried out by using: capillary water absorption test, infrared thermography (IRT), accelerated ageing test by salt mist, uniaxial compressive strength and drilling resistance test. The data obtained for pastes and mortars have been compared to each other and also with traditional materials commonly used in the building sector. The experimental results displayed a strong correlation between the rate of heat dispersion and the microstructure of the samples. In detail, the pastes show a more compact structure than mortars, which is responsible for a slower heat release and a lower capillary water absorption rate, as well as a better mechanical performance. IRT, used for the first time on these materials, revealed a high potential in providing feedback on other physical-mechanical features of alkali activated materials, commonly derived by using destructive methods. [ABSTRACT FROM AUTHOR]

A new semi-automated image processing procedure based on multivariate statistical analysis of X-ray maps of petrological and material science interest has been developed to generate high contrast pseudo-coloured images highlighting the element distribution between and within detected mineral phases. This new tool package, developed in Python and integrated with ArcGis ® , generates in only a few minutes several graphical outputs useful for classifying chemically homogeneous zones as well as extracting quantitative information through the statistical data handling of X-ray maps. The code, largely based on the use of functions implemented in ArcGis ® 9.3 equipped with Spatial Analyst and Data Management licences, has been suitably integrated with original cyclic functions that hugely reduce the time taken to complete lengthy procedures. In particular these tools, after the acquisition of any kind of multispectral images allow fast and powerful data processing for efficient illustration and documentation of key compositional and microtextural relationships in rocks and materials. [ABSTRACT FROM AUTHOR]

Abstract: Dealing with a moving target causes a motion effect (i.e. blurring) on the acquired images. This factor is an important source of measurement uncertainty while exploiting the Digital Image Correlation (DIC) technique. Therefore, the present study aims to evaluate and improve DIC uncertainty in dynamic conditions in the case of translating target. The study focuses on 2D DIC. In the case of 3D DIC similar problems arise, and therefore a complete understanding of two dimensional conditions will be of great help for further studies which deal with 3D conditions. The whole work can be divided into two main parts. In the first part, two different methods to simulate the motion effect on a reference image are proposed, discussed and validated. These methods allow simulating the acquired images in a real dynamic test and estimating the measurement uncertainty caused by the motion effect. The validation is performed by conducting several harmonic vibration tests with an electromagnetic shaker. In the second part of the study a numerical technique is proposed to estimate the motion effect present in an acquired image. This technique gives two main advantages. First of all, since the motion effect itself has a known influence on the uncertainty of measurement (first part of the study), we can predict the DIC׳s uncertainty by just having an acquired image. Furthermore, this numerical technique is used in the last part of this work to improve the performances of DIC in dynamic applications. In this way the bias error and the uncertainty of measurements were considerably decreased. [Copyright &y& Elsevier]

Abstract: This work is focused on the petro-archeometric characterization of the fine pottery production of the archaeological site of Gela (Sicily). Thirty-five samples coming from three Archaic and Hellenistic kilns and five coming from an Hellenistic house, were investigated by means of optical microscopy, XRD and XRF analysis. With the exception of some ceramics which are undoubtedly imported, all the samples have similar petrographic features, but on the basis of chemical composition, we can distinguish two different groups. The presence of two local productions is confirmed by the comparison with locally outcropping sediments and with archaic and modern bricks of sure Geloan production. This result is particularly significant for the definition of reference groups of this wealthy polis that played an important trading role in the Mediterranean area. [Copyright &y& Elsevier]

• Binary mixtures with pyroclastic deposits (Mt. Etna volcano) and metakaolin. • Alkaline activating solutions based on Na or K cation. • Polycondensation reaction monitoring on fresh pastes through In situ FTIR analysis. • Performance in terms of structure, compressive strengths and porosity. The huge availability of volcanic deposits in Mt. Etna volcano and the wide use of volcanic materials as aggregates in local architecture encouraged us to apply them in alkaline environment to produce geopolymeric binders to restore historical buildings of Mt. Etna area. Two clusters of samples for each volcanic precursor (volcanic ash and ghiara paleo-soil) were produced, using 10 and 20% wt. of metakaolin and two different alkaline solutions based on sodium and potassium respectively. A comparative study was made in relation to activators used, focusing on evaluation of polycondensation step (in ATR); chemical and structural characterization (FT-IR); TGA analysis, qualitative XRD analysis and mechanical compressive test after 7 and 21 curing days. ATR results confirmed the occurrence of geopolymerization for all samples; FT-IR analysis showed a higher content of carbonates in potassium-samples, decreasing at increasing of metakaolin content. A low weight lost was recorded in consolidated samples, as well as a partial dissolution of volcanic phases. Higher mechanical compressive strengths for K-samples, reaching 89 MPa as highest value after 21 days, differently to sodium-samples (51 MPa) were recorded, reflecting the porosity of the different specimens. [ABSTRACT FROM AUTHOR]

[Display omitted] • Evaluation of activating solution influence on high temperature resistance in AAMs. • Higher availability of silicon and aluminum and better feasibility of the pastes. • Monitoring formation of Si-O-Si and Si-O-Ca networks. • Positive influence of the new crystallizations on mechanical resistance after 1000 °C. • Densification behavior of K sample contrary to the melting of that Na. Thermal performances at 1000 °C of volcanic ash-based alkali-activated materials by both sodium or potassium solutions have been tested. Once defined the feasibility for the potassium set, a multidisciplinary characterization including spectroscopic, thermal, mechanical, diffractometric before and after treatment and dilatometric analyses was applied. The formation kinetics of different networks was evaluated. A correlation between the high mechanical properties and the least amount of water was observed in non-treated samples. Treated samples at 1000 °C showed higher compressive strengths due to the crystallization of wollastonite, leucite and nepheline. Thermal stability was observed increased with the solid content in the potassium-based formulations. [ABSTRACT FROM AUTHOR]

• Analysis of ghiara- and azolo-based mortars from historic buildings of Catania. • Image processing procedure based on multivariate statistical analysis of X-ray maps. • Quantification of the hydraulic phases within the binder of mortars. • Different distribution of the hydraulicity index in the two examined mortars. • Better technological performance and mechanical resistance of ghiara mortars. Since Roman Age, the reactiveness of the mortars was empirically sought using different aggregates added to lime to confer hydraulic properties. With the advent of microanalytical studies, great strides have been made toward a better understanding of how the aggregates can catalyze the formation of hydraulic phases. However, due to the small scale and the different distribution speeds of the reactions, the techniques routinely used are not fully performing for answering this task. In this work, an innovative semi-automated image processing procedure based on the multivariate statistical analysis of X-ray maps is adopted to highlight and quantify, for the first time, the hydraulic behavior of mortars in terms of reactivity between binder and aggregate. The method proposed has been applied to two different volcanic-based mortars (known as "ghiara- and azolo-mortars") collected from historic buildings in Catania (Sicily, Italy). Obtained results allowed identifying, in both mortars, four distinct compositional sub-zones within the binder as well as mapping the distribution of the Hydraulicity Index (HI). This latter resulted to be quite higher for the ghiara mortar (HI from properly hydraulic lime to cement for ∼50% of the binder) with respect to the azolo one (HI from properly hydraulic lime to cement for ∼10% of the binder). [ABSTRACT FROM AUTHOR]

Highlights: [•] Simple sol–gel synthesis of nanocrystalline titania is proposed. [•] The photocatalytic properties of the sol are studied upon UV irradiation. [•] Satisfactory photodegradation of methyl-orange on the limestone coated surfaces is obtained. [•] The titania coatings do not change the properties of the limestones. [ABSTRACT FROM AUTHOR]

Abstract: In the present work, an analytical characterization of painted plaster samples coming from ancient buildings dated back to 2nd cent. B.C., located in Licata (Sicily, Southern Italy), has been carried out. The investigation has been performed through different spectroscopic techniques: X-ray fluorescence (XRF) using an handheld energy-dispersive XRF analyzer, scanning electron microscopy equipped with an Energy Dispersive Spectrometry microanalysis detector (SEM-EDS) and Fourier transform infrared absorbance spectroscopy (FT-IR). The main goal is to identify the plaster and pigments material. In particular, the XRF investigation of surfaces is the first step for a preliminary elemental characterization. Then, through SEM-EDS measurements, a quantitative analysis of the chemical composition of the plaster and the pigmenting agents along with eventual components related to deterioration processes has been obtained. Finally, FT-IR absorbance spectra have proven to be a useful tool to investigate the molecular nature of the used materials. [Copyright &y& Elsevier]

[Display omitted] • In-situ analysis for the diagnosis of the state of conservation of stone buildings. • Decay of limestone facades in historical buildings of Catania (Sicily). • Discrimination of the superficial coatings used in different historical periods. Historical buildings of Catania city centre (Eastern Sicily, Italy) have been built for centuries using natural stone materials from local resources, including volcanic and carbonate rocks, matched in a peculiar bichromy. Particular attention is here paid on the carbonate rocks, which are generally more susceptible to decay processes. Such stones are sometimes covered by pigmented coatings with decorative purposes as well as protective function. In some cases, these nuances are partially or totally lost due to the decay processes which can also cause a modification of the chemical composition of the stone surface. The aim of this study is to prove the effectiveness of in situ X-ray Portable Fluorescence and colorimetric techniques for the characterization of degradation forms and colour modifications affecting several limestone-made historical buildings of the city centre of Catania. The results obtained, processed by means of multivariate statistical analysis, highlighted that all the stone surfaces exposed outdoor exhibit both chromatic and chemical modifications. In addition, three diverse types of superficial treatments have been identified, being related to different construction periods [ABSTRACT FROM AUTHOR]

This work is a part of a research project conducted in order to characterize the volcanic ash from Mount Etna, focusing in particular on the surface reactivity of ashes and possible consequence for human health. In this framework, a sampling campaign began on 16 March 2013, taking advantage of the intense volcanic activity on Etna. The interaction between volcanic ash and human organism was simulated treating two classes of representative Etnean particles with ultrapure water (grainsize of 850 um) and Gamble's solution mimic lug fluids (grainsize <38 μm) with the aim to evaluate the risk due to gastric and respiratory exposure to volcanic particles. The leachates were analysed by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Ionic Chromatography (CI) in order to highlight possible dangerous elements released in water solutions according to USGS protocol. Analyses of Gamble's solution highlighted a release of elements smaller than in watery solutions and always below the thresholds established by the Italian law. On the contrary, analyses of watery solutions evidenced, for some elements (B, Cd, Ni and As), levels higher than permitted by Italian law. Considering the effects of these elements on human health, further investigations are necessary and currently carried out in order to better constrain the release process and the specific effects on human organism. Unlabelled Image • Volcanic ashes emitted during explosive eruptions may have effects on human health. • Surface reactivity of ashes from Mount Etna activity was characterized. • Interaction with human organism was simulated by leaching experiments. • Most of the released elements are well below the Italian legal limits. • Few elements (B, Cd, Ni and As) are released in higher level than permitted. [ABSTRACT FROM AUTHOR]

• A complex mineralogical assemblage was revealed. • Fe(II) and Fe(III) species were detected in a variety of coordination environments. • The Fe oxidation state and speciation is not affected by water. • Significant changes were evidenced as a function of particle granulometry. • Ashes surface features may prevent direct exposure to mobile and toxic Fe(II). Volcanic ashes particles are subjected to substantial modification during explosive eruptions. The mineralogical and compositional changes have important consequences on the environment and human health. Nevertheless, the relationship between the speciation of iron (Fe) and the mineralogical composition and particle granulometry of the ashes, along with their interaction with water, are largely unknown. In particular, the Fe oxidation state and the possible formation of new Fe-bearing phases in presence of S, Cl, and F in the plume are key points to assess the impact of the ashes. Fragmental material ejected during volcanic activity (tephra) in 2013, was collected on the Mt. Etna (Italy) and investigated using a multi-technique approach that included conventional Electron Paramagnetic Resonance (EPR), high field EPR (HFEPR), EchoEPR, and Fe K-edge X-ray Absorption Spectroscopy (XAS). These element-selective techniques allowed obtaining a detailed information on the oxidation state and coordination environment of Fe, and of its speciation in the ash samples as a function of the granulometry. A complex mineralogical assemblage, consisting of variable amounts of nanometric crystalline Fe inclusions in a glass matrix, and of Fe-oxides and Fe-sulfur phases was revealed. A risk assessment of the ashes is attempted. [ABSTRACT FROM AUTHOR]

• Aeolian pumice can be used as raw materials to design novel cements via alkali activation. • Binary mixtures of pumice and metakaolin produce lightweight materials with good mechanical strength. • Pumice-based geopolymers can be used for restoration purposes. In this paper, the potentialities of pumice-based geopolymers have been explored with the aim to evaluate their use as restoration materials. In particular, the behaviour of Aeolian pumice during alkali activation process, either alone or in binary mixtures with metakaolin, has been assessed using sodium hydroxide and sodium silicate activators. Hardened products were characterized by: X-ray diffraction; infrared spectroscopy; thermo gravimetry and electron microscopy. Furthermore, Hg-intrusion porosimetry, water absorption, compressive strength and colorimetric measurements were carried out in order to define the technical features of the produced geopolymers. The results reveal that Aeolian pumice mixed with small quantities (20–30 wt%) of metakaolin is suitable for the formation of lightweight geopolymers which exhibit an accessible porosity up to 30%, water absorption of about 18.0%, and satisfactory 28-day compressive strength up to 12 MPa. These values indicate good breathability and adaptability to the substrates of the proposed formulations. Final products display a homogeneous and compact amorphous matrix, and their colour mimic the original stones, highlighting their potential role in Cultural Heritage preservation. [ABSTRACT FROM AUTHOR]