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Virtues of Giambologna from Grimaldi Chapel Archaeometrical Characterization
No full textThis scientific investigation on metal artwork is meant to expand knowledge regarding the technical skills developed by artists in sculpture manufacturing. Moreover all the gathered data support the speculation about the motivations behind the choices of certain material or a specific manufacturing method (e.g., economic or technical reasons, or both). The subject of this study is the Virtues sculptural group made at the end of the XVI century by Giambologna to decorate the Grimaldi Chapel in the church of San Francesco di Castelletto (Genoa, Italy). Six life-size statues depicting Charity, Justice, Hope, Fortitude, Faith, and Temperance (i.e., the artwork discussed in this article); seven bas-reliefs; and six winged representations of putti are what remains of the original monumental project. X-ray fluorescence, a nondestructive investigation method, was applied to determine the chemical nature of the metallic substrate and of the "artistic" and natural patinas. The achieved results allowed for distinguishing variations in the content of the major alloying elements that might correspond to a motivated will of the artist connected to technical and aesthetic aims: the production of defect-free and golden bronze artifact
Micro-Raman spectroscopy for the characterization of artistic patinas produced on copper-based alloys
No full textIn order to contribute to the improvement of restoration and conservation sciences of metallic artefacts belonging to Cultural
Heritage, a wide research has been started on the study of artificial (artistic) and natural (corrosion or alteration) patinas of
copper-based alloys.
Micro-Raman spectroscopy (mRS) coupled with scanning electron microscopy (SEM) equipped with energy Dispersive X-Ray
Spectroscopy (EDXS) were applied for the characterization of a number of patinas made on metallic substrate reproducing the
typical copper-based alloys used for statuary. A non alloyed copper sheet has been also used to simulate the architectural
cover typically used after a specific cold spray coating.
To reach these goals, a number of patinas were experimentally produced in our laboratory using the torch technique and
reactive solutions based on water as a solvent containing, respectively, copper nitrate, iron nitrate and potassium sulfide
(‘liver of sulfur’). The only exception is a sample reproducing the architectural cover of a recent building nearly completely
covered with copper sheets coated with copper salts.
All the produced patinas were aged in a salt spray chamber and then studied with mRS, SEM and EDXS in order to understand
their evolution between the two known terms and therefore the reactions involved in all patinas. mRS allowedus todetect asmain
constituents of the ‘artistic’ patinas, before and after ageing: copper oxides (Cuprite and Tenorite), copper nitrates (Rouaite and
Gerhardtite), copper chlorides (Botallackite, Atacamite and Paratacamite), a copper sulfate (Posnjakite), iron oxides (Magnetite
and Hematite) and an iron hydroxide (Limonite)
Aging of materials at inlet and outlet fuel manifolds in a SOFC stack
No full textAnalyses performed on a stack operated for more than 4000h at 750°C at high fuel utilization (80%) revealed significant differences in aging behaviour of stack components when comparing fuel inlet and fuel outlet areas. Two samples were cut from the fuel inlet and outlet manifolds of the operated SOFC stack. The glass-ceramic sealing material and the interconnect alloy were exposed to a dual atmosphere (external air and internal fuel stream). The fuel composition was dry H2/N2 (60:40 vol. %) at the inlet and H2O/H2/N2 (48:12:40 vol. %) at the outlet. The stack was operated in co-flow configuration, with a large excess of air. It was found that the interfaces between the seal and the alloy were significantly affected by the difference in fuel composition. The sealant exposed to the outgoing air was significantly polluted by chromium generated in the stack and transported by the air stream. These investigations therefore reveal that the long-term evolution of the sealing and of the metallic support depends on the local conditions in the stack, as well as on additional interactions with other degradation phenomena
K44M ferritic stainless steel as possible interconnect material for SOFC stack operating at 600 °C: Characterization of the oxidation behaviour at early working stages
No full textA commercial ferritic stainless steel (FSS) known as K44M (Type 444, according to ASTM A240, DIN 1.4521 according to NF EN 10088-2) was aged in static air in two differing thick-nesses (i.e. 1.5 and 0.4 mm) at a thermal cycle corresponding to the curing phase of anexperimental glass used as sealing in solid oxide fuel cell (SOFC) stacks, and to an ageingprocess in air of 200 h at 600C.The characterization performed on the aged samples after the complete treatment andat each step of the thermal cycle allowed to investigate the scale formed depending on thetemperature and to the thickness of the sample
Behavior of commercial ferritic stainless steel during the starting process of intermediate temperature SOFC stacks
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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