An Ancient Egyptian Multilayered Polychrome Wooden Sculpture Belonging to the Museo Egizio of Torino: Characterization of Painting Materials and Design of Cleaning Processes by Means of Highly Retentive Hydrogels

This contribution focuses on the conservation of an Egyptian wooden sculpture (Inventory Number Cat. 745) belonging to the Museo Egizio of Torino in northwest Italy. A preliminary and interdisciplinary study of constituent painting materials and their layering is here provided. It was conducted by means of a multi-technique approach starting from non-invasive multispectral analysis on the whole object, and subsequently, on selected micro-samples. In particular, visible fluorescence induced by ultraviolet radiation (UVF), infrared reflectography (IRR) and visible--induced infrared luminescence were used on the whole object. The micro-samples were analysed by means of an optical microscope with visible and UV light sources, a scanning electron microscope (SEM) with an energy-dispersive X-ray spectrometer (EDX), Fourier transform infrared (FT-IR) spectrometer, pyrolysis-gas chromatography/mass spectrometer (Py-GC/MS) and micro-particle induced X-ray emission (PIXE). The characterization of the painting materials allowed the detection of Egyptian blue and Egyptian green, and also confirmed the pertinence of the top brown layer to the original materials, which is a key point to design a suitable surface treatment. In fact, due to the water sensitiveness of the original materials, only few options were available to perform cleaning operations on this artwork. To setup the cleaning procedure, we performed several preliminary tests on mockups using dry cleaning materials, commonly used to treat reactive surfaces, and innovative highly water retentive hydrogels, which can potentially limit the mechanical action on the original surface while proving excellent cleaning results. Overall, this study has proved fundamental to increase our knowledge on ancient Egyptian artistic techniques and contribute to hypothesize the possible provenance of the artefact. It also demonstrated that polyvinyl alcohol-based retentive gels allow for the safe and efficient cleaning of extremely water sensitive painted surfaces, as those typical of ancient Egyptian artefacts.

Фізичне моделювання та діагностика попадання сторонніх предметів в обертову систему

The paper analyzes the vibroacoustic signals obtained by physical modeling of the rotating system, for example, an aircraft gas turbine engine, in the conditions of steady-state and non-steady-state modes. An air starter (supercharger) is used as a physical model of a rotating system, which is driven by a DC motor. The measuring system uses a dynamic microphone with an amplifier, a tachometer, a two-channel digital oscilloscope, a personal computer with technological and special software. The simulation of the ingress of foreign objects into the rotating system is performed by throwing paper balls during the rotation. The multilevel processing based on sequential application of methods of frequency-time analysis, multispectral analysis, and fractal analysis is proposed and substantiated for processing of measured vibroacoustic signals. The results of the frequency-time analysis showed that at the time of throwing the balls the intensity of the components at higher frequencies increases. For fragments of signal realization without throwing and with the throwing of balls the multispectral analysis is carried out and estimates of the bispectrum modulus are received in the form of contour images. At the third level of signal processing, the Minkowski dimension of the contour images of the bispectrum module estimates is determined. The Minkowski dimension is an integral quantitative indicator of the geometry of isolines and differs in value for the selected fragments of the vibroacoustic signal. So it can be used as a diagnostic sign of a foreign object entering the rotating system at the final level of processing. The obtained results can be used to improve the systems of condition monitoring of complex rotating systems, increase sensitivity, expand functionality and provide multi-class diagnostics in the event of damage and violation of normal operating modes

Multispectral Analysis of Miniature Nuragic Bronze Flasks

Miniaturized bronze flasks represent a small portion of a wide metallurgical production that flourished in Sardinia (Italy) between the Final Bronze Age (FBA) and the Early Iron Age (EIA). They replicate a well-known and symbolic type of object, the pilgrims’ flask, common in all Europe and Mediterranean basin, and have but few archaeological parallels. For these reasons, their characterization can be considered important from an archaeological perspective. Three flasks, preserved at the Antiquarium Arborense museum (Oristano), were analyzed by X-Ray Fluorescence Spectroscopy (XRF) and Raman spectroscopy, integrated by multispectral images. The samples, coming from illegal excavations, posed two problems: establishing their authenticity and investigating the alloy composition of such particular objects. All specimens presented a widespread degradation in the outer surface: XRF and Raman spectroscopy indicated the presence of copper oxides, calcium and copper carbonates deposits. The abscence of Zn, a clear marker of forgeries, was not detected by XRF. In two of the flasks, an unusual Sn content above 20%, was detected. For FBA and EIA, especially regarding southern Europe, Sn was extremely rare, and was possibly used with caution. Further results are presented herein.

Unmixing octopus camouflage by multispectral mapping of Octopus bimaculoides’ chromatic elements

Cephalopods camouflage abilities arise from highly specialized chromatic elements in their skin, chromatophores, iridophores, and leucophores, that enable them to display complex and rapidly changing color patterns. Despite the extensive study of these chromatic elements in squid and cuttlefish, full characterization of their individual optical response is still elusive in the Octopus species. We present here detailed multispectral analysis and mapping of the Octopus bimaculoides skin that allows to precisely identify the spatial distribution of the animal’s pigmented and structural elements. The mutual interaction of chromatophores and iridophores is also characterized both in terms of spectral response and spatial localization. The spectral information obtained through this analysis helps to understand the complexity and behavior of these natural tissues while continuing to serve as an inspiration for the fabrication of advanced, chromatically adaptable materials.

„Moartea autorului”. Analiza multispectrală a unui topos cultural

The present reflection proposes a novel investigation method in humanities, consisting in the analysis of local phenomena as originating in the dynamic of cultural `deep structures`. My focus falls on the death of the author which I consider to be a topos and a myth of last century’s humanities. The death of the author is associated with the Hegelian eschatological philosophy of history, but may also be deciphered as a consequence of the acute manifestation, within an entire culture, of the Kantian antinomy regarding the necessary existence of a transcendent being. As transcendent to the work, the author is refuted – because, as Hugo Friedrich shows, the modern artistic conscience intuited the empty ideality of traditional metaphysical notions –. Thus, the death of the author must be inquired upon not only as a particular phenomenon within the evolution of art, but also as a symptom of certain transformations that precede the aesthetical domain, transformations that are characteristic to the late Modernity and integrant of a `multispectral` analysis (with scopes in metaphysics, archetype and myth analysis). Such a methodological exigence is based on the assumption that a cultural phenomenon ought to be integrated within the scientific paradigm it expresses and also within the ontological and cosmological models around which it is articulated. An approach such as this shall reveal that the death of the author represents and intellectual version of the death of God, further assimilated to a cultural archetype, that of the death of Meaning. Consequently, the postmodern deicide represents the imposal of negation as a form of thought, a Western thought headed, with the end of Modernity, against the metaphysical tradition (of Presence) that it stems from. I assume that the self-destruction of Western tradition is symptom of a profound crisis of identity and I interpret it as a symbolic violence meant to redeem the fault of 20th Century’s atrocities, by cleansing the guilt the Western man experiences. My approach to the analysis of myth engages the actual debate regarding the canonical fights of the last few decades while trying to shed light on the way in which the symbolic deicide of the (`secularized`) author and auctor aims at imposing a new author and a new auctor to the symbolic products of culture. Ideology is the new auctorial authority.

A chronological proposal for El Castillo Cave (Puente Viesgo, Cantabria) based on its iconographic stratigraphy

Some years ago, we began a review of the work done by E. Ripoll in 1953. During this time, we have examined not only each and every one of the figures discovered by him, but have also expanded the list, reaching nearly all the 450 new figures in the entire cave. This significant increase is thanks to the use of new technologies, such as a 3D scanner, digital filters, multispectral algorithms, giga images, or the newest innovation, the use, for the first time in our studies on cave art, of hyperspectral methodology. The latter gives us access to a much wider light spectrum than the one created by multispectral analysis.

Multispectral analysis of the Martian dayglow from UVIS-NOMAD on board TGO

<p>The NOMAD instrument currently in orbit around Mars on board ESA's ExoMars Trace Gas Orbiter (TGO) includes UVIS, a UV-visible spectrograph covering the spectral range 200-700 nm. This instrument has two channels, one for solar occultation and a nadir channel essentially designed to analyse solar backscattered radiation. Since April 2019, the TGO spacecraft is occasionally tilted so that the nadir channel is pointed toward the Martian limb to observe the planetary airglow. A first success was the discovery of the forbidden oxygen green line at 557.7 nm that is ubiquitous in all UVIS limb dayside observations. This emission gives its characteristic colour to the terrestrial polar aurora but had was never been observed before in the airglow of other planetary atmospheres. This emission is excited by the interaction between solar radiation and CO<sub>2</sub> and shows a mean intensity peak near 80 km. More recently, the much weaker OI 630-nm emission has been detected following co-addition of several hundreds of UVIS spectra. It is much weaker than the green line, as a consequence of collisional deactivation of the long-lived O(<sup>1</sup>D) excited state. Both oxygen dayglow emissions have been successfully modelled. Molecular transitions are also identified in the UVIS ultraviolet spectrum, including the CO Cameron bands, the CO<sub>2</sub><sup>+</sup> ultraviolet doublet at 298-299 nm and the Fox-Duffendack-Baker (FDB) bands. They originate from the lower thermosphere near 120 km.</p><p>The seasonal-latitudinal evolution of the 557.7-nm emission will be described and compared with model simulations for the conditions of the observations. Simultaneous observations of dayglow emissions originating from different altitude will be available over a full Martian year. Coupled with model simulations, they provide constraints on the changing structure and composition of the Martian lower thermosphere, a region difficult to probe otherwise.</p><p> </p>

Geological context of recent Lunar landing sites using Multispectral analysis.

<p>Geological context of recent lunar landing sites using multispectral analysis. (Mcilquham J, Borst A, Allender E and Foing B)</p><p>The Moon Mineralogy Mapper (M3) was a guest instrument aboard the Chandrayaan-1 mission. The instrument collected spectral data, ranging from 430 nm to 3000 nm at an average resolution of 140 m/pixel. This research utilises M3 spectral data to visualise and understand the geology of lunar landing sites visited by Chang’e 4 and 5. The aims of this study are aligned to lunar exploration goals produced by the National Research Council. We use Python scripts to undertake data analysis, creating site maps using continuum removal methods and assigning RGB image channels to highlight absorption features of interest. The Chang’e 4 landing site is located on the lunar far side within the Von Karman crater, located in the large South Pole Aitken impact basin. At Von Karman lunar mantle or lower crustal material may be exposed in the central peak. This could provide valuable insights into lunar geological history. We create maps to visualise the location of pyroxene end-members and olivine-rich rocks of the Von Karman crater, adding data to understand the composition of the deeper lunar lithologies. Orbital data presented in this study can be compared with ground-truth data gathered from the Yutu 2 rover to confirm the minerals present. More recently the Chang’e 5 mission provided a further landing site for study. Using the same methods as presented above we will compare its spectral composition to the Chang’e 4 landing site. Our maps can help to understand the key factors used to determine a suitable landing site and potentially a suitable location for a lunar base. By comparing Chang’e landing sites this study provides a unique insight into the craters in which they landed, allowing direct comparisons to be drawn. Preliminary findings identify non-mare units within the Von Karman crater as well as various Ca-rich and Ca-poor pyroxene-bearing lithologies.</p>