FCT/UNL
DCr
A presente monografia pretende reunir e discutir toda a informação atualmente existente, fruto da pesquisa de microbiólogos, químicos e conservadores, na área da biodeterioração em materiais têxteis. Como tal, foram identificados os... more
A presente monografia pretende reunir e discutir toda a informação atualmente existente, fruto da pesquisa de microbiólogos, químicos e conservadores, na área da biodeterioração em materiais têxteis. Como tal, foram identificados os agentes biológicos e microbiológicos de deterioração destas cadeias poliméricas, que vão desde enzimas e fungos a insetos e roedores, que atacam preferencialmente fibras orgânicas. São focadas também as questões de preservação dos mesmos, sendo que se tratam da principal medida aquando da prevenção e combate deste tipo de deterioração.
The article “Animal glues: a review of their key properties relevant to conservation” is about collagen-based animal glues used in conservation of artefacts, serving as adhesives, binders and consolidants for organic and inorganic... more
The article “Animal glues: a review of their key properties relevant to conservation” is about collagen-based animal glues used in conservation of artefacts, serving as adhesives, binders and consolidants for organic and inorganic materials. These kind of glues are polymers derived from mammalian (like rabbit skin, hide and bone glues and gelatin) or fish collagen (like sturgeon glue) which have lots of physical, mechanical and chemical properties. These should always be evaluated when used with a purpose in conservation. The main goal of this article, written by Nanke C. Shellmann, is to provide a review of the literature, which most is not readily accessible to conservators and can be ambiguous or contradictory.
Pena National Palace (Sintra, Portugal) was built in the 19th century and tiles, typical of Portuguese and Oriental art expression, were widely used as decorative elements throughout the outside walls of the palace. This study focuses on... more
Pena National Palace (Sintra, Portugal) was built in the 19th century and tiles, typical of Portuguese and Oriental art expression, were widely used as decorative elements throughout the outside walls of the palace. This study focuses on a passageway (Triton tunnel) that is covered with distinct tile panels from the second half of the 19th century, attributed to Wenceslau Cifka. Unfortunately, at present these magnificent tiles are covered by a green and/or black patina caused by microorganisms, whose identification was carried out by culture and molecular methods, light microscopy, confocal laser scanning
microscopy, and scanning electron microscopy. Our results showed that the biological patina is composed of microalgae, cyanobacteria, bacteria, and some lichenized fungi. Some of these microorganisms penetrate within fissures and pores, producing tile biodeterioration.
microscopy, and scanning electron microscopy. Our results showed that the biological patina is composed of microalgae, cyanobacteria, bacteria, and some lichenized fungi. Some of these microorganisms penetrate within fissures and pores, producing tile biodeterioration.
This study aimed at evaluating the influence of ageing on the bioreceptivity and biodeterioration of glazed tiles by fungi. These microorganisms have been identified in historical tile colonizing microbial communities. A 12-month... more
This study aimed at evaluating the influence of ageing on the bioreceptivity and biodeterioration of glazed tiles by fungi. These microorganisms have been identified in historical tile colonizing microbial communities. A 12-month laboratory colonization experiment was conducted for pristine and artificially aged tile models inoculated with
Devriesia imbrexigena. Fungal growth was evaluated by digital image analysis after incubation. Scanning electron microscopy and micro-Raman spectroscopy were conducted to assess biodeterioration. The organic acids exuded by D. imbrexigena induced the precipitation of calcium oxalate on the glazed surfaces causing biodeterioration. Results also showed that the ageing degree was not related to bioreceptivity.
Devriesia imbrexigena. Fungal growth was evaluated by digital image analysis after incubation. Scanning electron microscopy and micro-Raman spectroscopy were conducted to assess biodeterioration. The organic acids exuded by D. imbrexigena induced the precipitation of calcium oxalate on the glazed surfaces causing biodeterioration. Results also showed that the ageing degree was not related to bioreceptivity.
ABSTRACT: The conservation of the Monastery of Santa Clara-a-Velha (Coimbra, Portugal) includes the open-air display of the ceramic tiles that pave the Main Cloister, some of which exhibit surface scaling and flaking. The possibilities of... more
ABSTRACT: The conservation of the Monastery of Santa Clara-a-Velha (Coimbra, Portugal) includes the open-air display of the ceramic tiles that pave the Main Cloister, some of which exhibit surface scaling and flaking. The possibilities of minimizing this loss of material resorting to two TEOS-based consolidants were assessed by characterizing changes in open porosity, water absorption, drying, colorimetric and drilling resistance features. Products were applied on selected tile samples by brush, via capillary uptake and using cellulose poultices. Results showed that the application method distinctively influences the product intake; for the samples treated by brush, the use of drilling tests to evaluate the penetration depth of the consolidants on these particularly abrasive materials is furthermore discussed.
- by Doria Costa and +1
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