1,721,017 research outputs found
Mineral treatments for the conservation of cultural heritage materials. Analytical characterization and trial application of barium oxalates and aluminates
No full textMineral treatments for the conservation of cultural heritage materials. Analytical characterization and trial application of barium oxalates and aluminate
Le preesistenze archeologiche
No full textL'area occupata dal settecentesco palazzo Donini di Perugia si connota come una zona urbana a forte vocazione residenziale nel periodo romano, carattere desumibile dalla presenza di numerosi resti di domus e di pozzi particolarmente concentrati proprio in quest'area. Dalle fondamenta di Palazzo Donini sono emersi i resti di un singolare sepolcreto attribuibile con ogni probabilità ad un contesto funerario ricavato all'interno di una delle più antiche chiese urbane perugine, destinata, per le proprie caratteristiche, probabilmente, ad accogliere le spoglie di un martire.The area occupied by the eighteenth-century Palazzo Donini Perugia is characterized as an urban area with a strong residential area in the Roman period, character deduced from the presence of numerous remains of domus and wells particularly concentrated precisely in this area. From the foundations of the Palazzo Donini showed the remains of an unusual burial is likely attributable to a funerary context housed in one of the oldest urban churches of Perugia, who by reason of their characteristics, probably, to house the remains of a martyr
LabSTECH European survey on methods and materials for the conservation of cultural heritage: results and perspectives
No full textNon-explosive magma–water interaction in a continental setting: Miocene examples from the Eastern Cordillera (central Andes; NW Argentina)
No full textEffects of atmospheric NOx on biocalcarenite coated with different conservation products
No full textOne of the most important factors of calcareous stone decay is the chemical attack caused by atmospheric pollutants
dissolved in water, in particular acidic gases such as SOx, NOx and CO2. The treatment of stone artefacts with hydrophobic
products reduces the water uptake of the rock and is, therefore, considered a ‘‘protective treatment’’. The aims of the present
study were the observation of the effects of NOx on a biocalcarenite (Lecce stone) and the evaluation of the performance
of protective products (Paraloid B72 and a fluoroelastomer) normally used in stone conservation. A system for
the simulation of accelerated ageing has been assembled and the Lecce stone samples, treated with polymeric products,
have been exposed to NO2 (nearly 1 ppm) during thermo hygrometric cycles. The nitrite and nitrate salts formed on
the specimens have been determined by ion chromatography. Both the polymeric products tested have given high hydrophobic
properties to the stone, even if they do not assure satisfactory protection toward NO2 exposure. Actually, their
protective efficacy, or ability to reduce the acidic attack of NO2, quickly decreases when the ageing period increases. Paraloid
B72 seems more effective than fluoroelastomer because, on the samples treated with the latter, higher amounts of
nitrites and nitrates have always been detected. In contrast, non-treated samples – used as reference – have shown a constant
increase in the amount of nitrates and nitrites during ageing. However, the surface analyses of the stone samples, by
environmental SEM and l-laser profilometry, did not show any change in superficial morphology after the ageing, suggesting
that NO2 acts inside the pores
Study and synthesis of organic precursors for salt treatments developed to protect and strengthen building materials and "frescos"
No full textAn attempt to find out possible ways to synthesise sulphates and oxalates, to be utilised for strengthening and consolidating limestone and frescos surfaces was made. Particularly organic sulphates were prepared and tested for their reactivity with barium salts, trying to obtain slow sulphates hydrolysis and, so, BaSO4 precipitation. Different solutions were applied on Opificio delle Pietre Dure ́s standards using different methodologies and applications times. The characterisation of chemical interactions between carbonaceous bodies and solutions was done by X-ray diffraction (XRPD), Fourier transformed infrared spectroscopy (FTAR), scanning electron microscopy (SEM-EDS). The synthesis of organic sulphates resulted not difficult and the solutions are very easy to use. More difficult was oxalate synthesis. The application results are promising
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
- …
