Characterization and digital restauration of XIV-XV centuries written parchments by means of non-destructive techniques. Three case studies

Parchment is the primary writing medium of the majority of documents with cultural importance. Unfortunately, this material suffers of several mechanisms of degradation that affect its chemical-physical structure and the readability of text. Due to the unique and delicate character of these objects, the use of nondestructive techniques is mandatory. In this work, three partially degraded handwritten parchments dating back to the XIV-XV centuries were analyzed by means of X-ray fluorescence spectroscopy, µ-ATR Fourier transform infrared spectroscopy, and reflectance and UV-induced fluorescence spectroscopy. 'e elemental and molecular results provided the identification of the inks, pigments, and superficial treatments. In particular, all manuscripts have been written with iron gall inks, while the capital letters have been realized with cinnabar and azurite. Furthermore, multispectral UV fluorescence imaging and multispectral VIS-NIR imaging proved to be a good approach for the digital restoration of manuscripts that suffer from the loss of inked areas or from the presence of brown spotting. Indeed, using ultraviolet radiation and collecting the images at different spectral ranges is possible to enhance the readability of the text, while by illuminating with visible light and by collecting the images at longer wavelengths, the hiding effect of brown spots can be attenuated

Characterization and digital restauration of XIV-XV centuries written parchments by means of non-destructive techniques. Three case studies

Parchment is the primary writing medium of the majority of documents with cultural importance. Unfortunately, this material suffers of several mechanisms of degradation that affect its chemical-physical structure and the readability of text. Due to the unique and delicate character of these objects, the use of nondestructive techniques is mandatory. In this work, three partially degraded handwritten parchments dating back to the XIV-XV centuries were analyzed by means of X-ray fluorescence spectroscopy, µ-ATR Fourier transform infrared spectroscopy, and reflectance and UV-induced fluorescence spectroscopy. 'e elemental and molecular results provided the identification of the inks, pigments, and superficial treatments. In particular, all manuscripts have been written with iron gall inks, while the capital letters have been realized with cinnabar and azurite. Furthermore, multispectral UV fluorescence imaging and multispectral VIS-NIR imaging proved to be a good approach for the digital restoration of manuscripts that suffer from the loss of inked areas or from the presence of brown spotting. Indeed, using ultraviolet radiation and collecting the images at different spectral ranges is possible to enhance the readability of the text, while by illuminating with visible light and by collecting the images at longer wavelengths, the hiding effect of brown spots can be attenuated

Improved photocatalytic properties of doped titanium-based nanometric oxides

Photocatalysis is considered one of the most promising technologies for applications in the environmental field especially in the abatement of water-soluble organic pollutants. In this field, titanium dioxide nanoparticles have drawn much attention recently; however, the use of this oxide presents some limitation since it allows to obtain high photoresponse and degradation efficiency only under UV light irradiation, that represents the 3 to 4% of the solar radiation, so preventing its environmental large-scale applications under diffuse daylight. In this work the photocatalytic efficiencyoftitanium-based oxides systems containing alkaline earth metals such as barium and strontium, prepared by a simple sol-gel method was investigated, evaluating the degradation of methylene blue as model compound under UV and visible light irradiation. The results were compared with those obtained with Degussa P25 titanium dioxide. The achieved degradation percentage of methylene blue are very promising showing that under visible light irradiation it is possible to obtain a maximum dye removal percentage ~ 50 % higher than that obtained with the Degussa P25

Steam reforming of model compounds from biomass fermentation over nanometric ruthenium modified nickel-lanthanum perovskites catalysts

Nanometric ruthenium-modified LaNiO3 perovskites prepared by coprecipitation method in aqueous and non-aqueous solvents were tested as catalysts in the steam reforming of butanol, acetone and ethanol and their mixture, named ABE, usually produced by fermentation. ABE is potentially of great interest for hydrogen production, notwithstanding the strong tendency of this mixture of oxygenated compounds to produce coke in the steam reforming conditions. The tested catalyst showed high feed conversions with improved stability

Viable Recycling of Polystyrene via Hydrothermal Liquefaction and Pyrolysis

Chemical recycling is considered one of the most sustainable solutions to limit the environmental issues related to plastic waste pollution, whereby plastic is converted into more valuable compounds when mechanical recycling is not feasible. Among the most critical fast-growing components of municipal solid waste, polystyrene represents 1/3 of the filling materials in landfills. In this work, the chemical recycling of polystyrene via two main thermochemical processes is investigated: pyrolysis and hydrothermal liquefaction (HTL). The influence of temperature (HTL: 300-360 & DEG;C and pyrolysis: 400-600 & DEG;C) and reaction time (HTL: 1-4 h; pyrolysis: 30 min) on the products obtained was studied. The obtained liquid and solid products were analyzed by using gas chromatography-mass spectrometry (GC-MS), an elemental analysis (EA), Fourier-transform infrared spectroscopy (FT-IR) and a thermogravimetric analysis (TGA). During HTL, a temperature of 360 & DEG;C and reaction time of 4 h were needed to completely decompose the polystyrene into mainly oil (83%) and water-soluble compounds (10%). The former was mainly composed of aromatics while the water phase was mainly composed of aromatics and oxygenated compounds (benzaldehyde and acetophenone). The pyrolysis led to the formation of 45% gas and 55% oil at 500 & DEG;C, and the oil was 40% styrene. Pyrolysis was thus more selective towards the recovery of the styrene monomer while the HTL can be an effective process to produce renewable aromatics

Molecular crystallization inhibitors for salt damage control in porous materials. An overview

The use of inhibition chemicals holds the prospect of an efficient strategy to control crystallization in porous materials, thereby potentially contributing to the prevention or mitigation of the salt decay phenomenon in modern as well as historical building materials in a more sustainable manner. In this review, we first provide an essential background on the mechanism of salt crystallization and on the factors influencing this phenomenon; next, we illustrate the mechanism at the basis of the action of crystal growth inhibitors, and critically discuss the major advances in the development of different families of inhibitors, particularly focusing on their influence on salt transport and crystallization within the structure of porous media. Specifically, correlations between the crystallization inhibition processes in porous materials and variables, such as porous substrate composition and properties, contaminant salt type and concentrations, microclimatic conditions, inhibiting solution concentration and properties, and application methods, will be highlighted. Environmental aspects, limitations, and problems associated with some inhibition chemicals are also taken into account. Finally, a survey and a discussion on the most representative experimental techniques and instrumentation available to assess qualitatively and quantitatively the inhibitor effectiveness, as well as recently developed modelling tools are given out

Soil Biocementation via Enzyme Induced Carbonate Precipitation (EICP) Method Employing Soybeans as a Source of Cheap Enzyme

In this work, the soil improvement technique via Enzyme Induced Carbonate Precipitation (EICP) was investigated by employing, as an alternative to expensive pure enzymes, enzymes extracted from agro-food wastes (tomato, apple, and soybean) such that the process is economically viable and fully embraces the concept of the circular economy. The feasibility of the process was evaluated by monitoring calcium carbonate precipitation in a sand sample. The effect of selected operative parameters was investigated during the injection into different grain size sand samples. The optimal operating conditions in terms of sand grain size, temperature, Urea/Calcium concentration were found. Results demonstrated the effectiveness of this alternative solution for EICP method in term of acquired material strength and the possibility to operate sand consolidation through an economically sustainable process

Efficient utilization of Al2O3 as structural promoter of Fe into 2 and 3 steps chemical looping hydrogen process. Pure H2 production from ethanol

Chemical Looping Hydrogen (CLH) allows the direct production of pure hydrogen exploiting the redox properties of Fe, with high flexibility on the type of reductant used. In this work, a highly pure hydrogen stream suitable for the direct use into Proton Exchange membrane Fuel Cells was produced, using bioethanol as renewable fuel. The influence of both redox temperature (675°C–750 °C) and chemical composition of the Fe-based particles (2 wt% and 40 wt% of alumina added) on the carbon formation rate during reduction step was also deeply analyzed. Al2O3 changed both FexOy redox kinetics and equilibrium phases, leading to a complete iron deactivation at high Al2O3 concentration. The addition of an air oxidation step (3 steps CLH) is fundamental to restore the redox activity, with a constant efficiency of about 30% at 750 °C for 10 cycles. Furthermore, Al2O3 promotes the ethanol conversion into carbon, undermining the hydrogen purity

Thermochemical characterization of polybenzimidazole with and without nano-ZrO2 for ablative materials application

During the ballistic atmospheric re-entry, a space vehicle has to withstand huge thermo-mechanical solicitations because of its high velocity and the friction with the atmosphere. According to the kind of the re-entry mission, the heat fluxes can be very high (in the order of some MW m−2) ;thus, an adequate thermal protection system is mandatory in order to preserve the structure of the vehicle, the payload and, for manned mission, the crew. Carbon phenolic ablators have been chosen for several missions because they are able to dissipate the incident heat flux very efficiently. Phenolic resin presents satisfying performance but also environmental drawbacks. Thus, a more environmental-friendly solution was conceived: a high-performance thermoplastic material, polybenzimidazole (PBI), was employed instead of phenolic resin. In this work PBI-ablative material samples were manufactured with and without the addition of nano-ZrO2 and tested with an oxyacetylene flame. For comparison, some carbon-phenolic ablators with the same density were manufactured and tested too. Thermogravimetric analysis on PBI samples was carried out at different heating rates, and the obtained TG data were elaborated to evaluate the activation energy of PBI and nano-filled PBI. The thermokinetics results for PBI show an improvement in thermal stability due to the addition of nano-ZrO2, while the oxyacetylene flame test enlightens how PBI ablators are able to overcome the carbon phenolic ablators performance, in particular when modified by the addition of nano-ZrO2