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Frankovic M.,Central Institute for Conservation in Belgrade | Novakovic N.,Cultural Heritage Preservation Institute of Belgrade | Matovic V.,University of Belgrade
Environmental Earth Sciences | Year: 2015

The Dark Gate is the monument of culture, part of the cultural and historical complex of the Belgrade Fortress. It is constructed of limestone blocks that after 270 years of exposure to environmental conditions and different anthropogenic influences show wide ranges of decay forms. During 2007, detail registration of all built limestone microfacies and weathering forms was done using tools of monument mapping. A correlation scheme “intensity– damage category” was made according to the type, intensity, and distribution of damage forms. For quantification of decay rate of the Dark Gate, damage indices were calculated on the bases of mapping results. Calculated values of damage indices (>3) reflected differences between separate zones of the gate (south–north façades, east–west oriented parts of the gate). This approach allowed assessment and comparison of weathering rates according to the gate’s position and the exposure of the stone to environmental influences. The linear damage index showed that the moderate damage is the dominant category on the entire monument, while the progressive damage index implies to the need of urgent intervention. After 7 years, re-evaluation of these parameters was done. New data of weathering mapping and recalculated values of damage indices reflected significant acceleration in decay rate. By comparing weathering maps and values of damage indices from 2007 and 2014, the eastern part of the gate was separated as the zone of the monument that had suffered the heaviest damage. Differences among the values of damage indices showed that the position of the gate is one of the main causes of the present state of stone blocks built in the Dark Gate. They also showed that a carefully made damage category scheme is a key diagnostic tool in each restoration project. © 2014, Springer-Verlag Berlin Heidelberg. Source


Petronic S.,University of Belgrade | Sibalija T.,Metropolitan University of Serbia | Burzic M.,University of Belgrade | Polic S.,Central Institute for Conservation in Belgrade | And 2 more authors.
Metals | Year: 2016

The paper presents a study on the surface modifications of nickel based superalloy Nimonic 263 induced by laser shock peening (LSP) process. The process was performed by Nd3+:Yttrium Aluminium Garnet (YAG) picosecond laser using the following parameters: pulse duration 170 ps; repetition rate 10 Hz; pulse numbers of 50, 100 and 200; and wavelength of 1064 nm (with pulse energy of 2 mJ, 10 mJ and 15 mJ) and 532 nm (with pulse energy of 25 mJ, 30 mJ and 35 mJ). The following response characteristics were analyzed: modified surface areas obtained by the laser/material interaction were observed by scanning electron microscopy; elemental composition of the modified surface was evaluated by energy-dispersive spectroscopy (EDS); and Vickers microhardness tests were performed. LSP processing at both 1064 nm and 532 nm wavelengths improved the surface structure and microhardness of a material. Surface morphology changes of the irradiated samples were determined and surface roughness was calculated. These investigations are intended to contribute to the study on the level of microstructure and mechanical properties improvements due to LSP process that operate in a picosecond regime. In particular, the effects of laser wavelength on the microstructural and mechanical changes of a material are studied in detail. © 2016 by the authors; licensee MDPI, Basel, Switzerland. Source


Pavic A.,University of Belgrade | Ilic-Tomic T.,University of Belgrade | Pacevski A.,University of Belgrade | Nedeljkovic T.,Central Institute for Conservation in Belgrade | And 2 more authors.
International Biodeterioration and Biodegradation | Year: 2015

Cultivable bacteria colonizing deteriorated modern painting on canvas were identified in order to evaluate their potential to deteriorate organic and inorganic painting's constituents. Different sampling and cultivation strategies enabled isolation of bacteria belonging to nine genera of Firmicutes, Proteobacteria, and Actinobacteria phyla. Overall predominant bacteria were species of Bacillus (51%) and Staphylococcus (36%) genera. Representatives of six different genera (Staphylococcus, Acinetobacter, Agrococcus, Janibacter, Rhodococcus, and Stenotrophomonas) were isolated for the first time from deteriorated canvas. Almost all isolated bacteria produced proteases, esterases, and lipases, which may be involved in deterioration of painting's binders and media. Bacteria expressing endocellulase were reported. Selected bacterial isolates were tested for ability to deteriorate six pigments. All tested isolates were able to grow in the presence of Ivory black, Red and Yellow ochre, as a sole source of phosphate and iron, inducing their fading. The majority of isolates induced solubilization of Zinc white and Cobalt deep green. Cadmium red pigment that inhibited the growth of a half of isolates proven to be the most toxic pigment. Isolated bacteria were equipped with all required metabolic prerequisites in order to pose a threat to the painting as a whole. © 2014 Elsevier Ltd. Source


Polic-Radovanovic S.,Central Institute for Conservation in Belgrade | Ristic S.,Institut Gosa | Stasic J.,Vinca Institute of Nuclear Sciences | Trtica M.,Vinca Institute of Nuclear Sciences
Journal of Non-Crystalline Solids | Year: 2012

Application of non-contact and rapid laser technique, which is minimally invasive, non-contaminant and efficient method, for ancient glass investigation and cleaning is highly desirable for restoration purposes. Irradiation of Roman glass dated from 1st to 4th/5th century AD with TEA CO 2 (wavelength 10.6 μm; pulse duration t p = 100 ns), Nd:YAG (wavelength 1064 nm and 532 nm; t p = 150 ps) and ruby laser (wavelength 694 nm; t p = 30 ns) in air ambience was studied. For all three lasers, moderate energy densities (15-30 J/cm 2) induced significant changes of morphology - from superficial exfoliation and occurrence of mosaic structure after few pulses to deep damages and hydrodynamic features after higher number of accumulated shots. Irradiation with moderate energy density, accompanied with plasma appearance in front of the samples, is convenient for numerous potential applications, particularly surface elemental analysis such as laser induced breakdown spectroscopy. On the other hand, lower densities are more suitable for Roman glass cleaning. Calculations of Roman glass surface temperature have shown that pulsed CO 2 laser is favorable for surface cleaning and optimal fluence is ~ 2 J/cm 2. This was confirmed by additional experiments for fluences 1.5 and 3 J/cm 2. Morphological changes on the Roman glass surface induced by lasers were studied by optical microscopy (OM) and scanning electron microscopy (SEM). The composition of Roman glass was determined by energy dispersive X-ray analysis (EDX) and inductively coupled plasma (ICP) method. Chemical analysis confirmed that the investigated glass dates from the Roman period. © 2012 Elsevier B.V. All rights reserved. Source


Zivkovic V.,Central Institute for Conservation in Belgrade | Dzikic V.,Central Institute for Conservation in Belgrade
Energy and Buildings | Year: 2015

Over the last few decades, research on the impact of environment on the cultural heritage and material response to processes of deterioration and at the same time introduction of risk-based methodology in developing preservation strategies lead to the revision of the guidelines for environmental management in the field of conservation of cultural heritage. Following this approach and taking into account minimal risks to collections Central Institute for Conservation in Belgrade has been working with museums in Serbia on determining the necessary environmental requirements for a specific collection and proposing adequate control strategies. The recommendations based on surveys of facilities and collections and monitoring of indoor environmental parameters, focus on eliminating sources of extreme conditions, and improving the existing conditions, or even maintaining the existing conditions when they are observed as stable both for collections and building. This strategy favors solutions which do not affect the building as a historical monument or its integrity or impose excessive investments in museum building. The paper will present issues and solutions for preservation of museum collections set in historic buildings, through several case studies and from the position of conservators, based on gathered data on collections, building and risks to collections. © 2014 Elsevier B.V. All rights reserved. Source

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