1,720,983 research outputs found
How Can Ozone and Relative Humidity Affect Artists’ Alkyd Paints? A FT-IR and Py-GC/MS Systematic Study
Full text linkKnowledge of the chemical–physical reactions that determine the main degradation behaviour of artists’ alkyd paints represents one of the main problems within the museum exhibitions. The collection and interpretation of these data on degradation phenomena, especially after ozone exposure at different relative humidity values, can be useful for their conservation needs. Therefore, a systematic investigation of these materials may help achieve this goal. Firstly, surface-level identification of the main functional groups of ad hoc created and aged alkyd paints was performed using attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR). Subsequently, these paints were investigated by pyrolysis–gas chromatography and mass spectrometry (Py–GC/MS), allowing for precise bulk identification of the organic compounds before and after accelerated ageing. A first successful attempt to provide quantitative Py–GC/MS data on alkyd-based paints is here presented and discussed. Comparing the results, it was possible to obtain new insights into the degradation behaviour of alkyd paints when exposed to ozone, allowing us to devise specific preventive and conservation strategies for these artistic materials
The role of bio-pollutants in the indoor air quality of old museum buildings: artworks biodeterioration as preview of human diseases
No full textIndoor air quality in buildings is strongly affected by chemical, physical, and biological agents. Long exposure to inadequate indoor air quality can be very dangerous for the building occupants and can lead to chronic diseases associated with the sick building syndrome (SBS). In this paper, the large presence of biological pollutants in the indoor rooms of an old building and its strict relationship with the outdoor/indoor air conditions were investigated studying Coronini Cronberg Palace Foundation, a historic house museum of the sixteenth century in Gorizia (Italy), where biological contamination affecting the artworks can soon become potentially harmful also for operators and visitors. Detailed aerobiological and microbiological analyses on organic natural materials, combined with a microclimate monitoring, were conducted to evaluate the influence of temperature and relative humidity levels within the Palace in the conspicuous growth and diffusion of microorganisms. Fungal and bacterial colonies damaging materials, mainly affected by the sudden fluctuations of hygrothermal values, were found to widely exceed Italian and international recommended levels for good air quality for both artworks and human beings. Understand their impact on human health would be strictly necessary to reduce biological risks for museum staff and cultural heritage users, but consequently to improve indoor air quality
Preliminary approach to protect Street Art from environmental agents and gaseous pollutants
No full textA critical review on the analysis of metal soaps in oil paintings
Full text linkUp to 70 % of the oil paintings conserved in collections present metal soaps, which result from the chemical reaction between metal ions present in the painted layers and free fatty acids from the lipidic binders. In recent decades, conservators and conservation scientists have been systematically identifying various and frequent conservation problems that can be linked to the formation of metal soaps. It is also increasingly recognized that metal soap formation may not compromise the integrity of paint so there is a need for careful assessment of the implications of metal soaps for conservation. This review aims to critically assess scientific literature related to commonly adopted analytical techniques for the analysis of metal soaps in oil paintings. A comparison of different analytical methods is provided, highlighting advantages associated with each, as well as limitations identified through the analysis of reference materials and applications to the analysis of samples from historical paintings
Data Fusion Approach to Simultaneously Evaluate the Degradation Process Caused by Ozone and Humidity on Modern Paint Materials
Full text linkThe knowledge of the atmospheric degradation reactions affecting the stability of modern materials is still of current interest. In fact, environmental parameters, such as relative humidity (RH), temperature, and pollutant agents, often fluctuate due to natural or anthropogenic climatic changes. This study focuses on evaluating analytical and statistical strategies to investigate the degradation processes of acrylic and styrene-acrylic paints after exposure to ozone (O3) and RH. A first comparison of FTIR and Py-GC/MS results allowed to obtain qualitative information on the degradation products and the influence of the pigments on the paints’ stability. The combination of these results represents a significant potential for the use of data fusion methods. Specifically, the datasets obtained by FTIR and Py-GC/MS were combined using a low-level data fusion approach and subsequently processed by principal component analysis (PCA). It allowed to evaluate the different chemical impact of the variables for the characterization of unaged and aged samples, understanding which paint is more prone to ozone degradation, and which aging variables most compromise their stability. The advantage of this method consists in simultaneously evaluating all the FTIR and Py-GC/MS variables and describing common degradation patterns. From these combined results, specific information was obtained for further suitable conservation practices for modern and contemporary painted films
A new methodology to characterize indoor variations of temperature and relative humidity in historical museum buildings for conservation purposes
No full textThis paper presents the study of the indoor climate of the Scuola Grande di San Rocco in Venice: it is a 16th-century emblematic example of a historical building. The renowned Tintoretto large paintings magnificently decorate the Scuola. The monitoring and control of microclimatic parameters such as Temperature (T) and Relative Humidity (RH) are pivotal to establish proper conservation policies in museums’ environments. Fragile artworks had been preserved for centuries in “natural climate” conditions, in the framework of historical buildings. In such ambiances, T and RH followed outdoor variations yet mitigated by the hygrothermal inertia of the building. Available indoor climate monitoring protocols consider T and/or RH values, but they do not allow a straightforward comparison of relative fluctuation of T and RH values through time. This paper presents a flexible methodology to visualize T and RH variations. The protocol considers the calculation of time-related index to understand the magnitude of daily (DF) or weekly fluctuations (WF), and the speed of the weekly fluctuations (SWF). The presented method introduces the calculation of climatic excursions index (ICE). The ICE is innovative because it allows us to compare the microclimate of different buildings, and it will enable us to quantify the time in which T and/or RH fluctuate outside reference ranges, even in the case that detailed information on materials and construction methods is lacking. Indoor microclimate variations have been compared with the outdoor ones: this helps to define the hygrothermal inertia of the building
Coupling anaerobic co-digestion of winery waste and waste activated sludge with a microalgae process: Optimization of a semi-continuous system
No full textThe possibility of obtaining energy or nutritive streams and bioremediation as an add-on opens new perspectives
for the massive culturing of microalgal biomass on waste waters generated by the agro-food sector. Ordinary
revenue streams are fully preserved, or even boosted, if they are used in microalgal cultivation; however, the
suitability of wastewaters depends on multiple nutritional and toxic factors. Here, the effect of modulating the
Olive Mill Wastewater (OMW) and cattle digestate (CD) fraction in the formulation of a growth medium on
biomass accumulation and productivity of selected biomass fractions and their relevance for biofuel and/or feed
production were tested for the microalga Scenedesmus dimorphus and for the cyanobacterium Arthrospira platensis
(Spirulina). Tests highlighted the strong S. dimorphus adaptability to digestate, as on OMW, compared to
A. platensis, with the maximum lipid storage (48 %) when culture medium was composed by 50 % of cattle digestate
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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