Bioreceptivity is an intrinsic property of stone, and is defined as the ability of a material to be colonized by living organisms. The fouling and staining of building stone material due to the activity of microorganisms presents a serious problem in modern as well as historical buildings, not only due to the aesthetic impact but also due to the deterioration of the material. Biological colonisation on stone materials is influenced by a number of factors, e.g. the intrinsic properties of the stone (porosity, roughness, permeability, mineral composition), environmental parameters (e.g. solar radiation, temperature, water regime, climate, etc.), and specific microclimatic parameters (e.g. orientation, exposure to shadow, permanent capillary humidity, etc.). In order to assess the bioreceptivity of building stones, use is often made of artificial colonisation experiments compromising the inoculation of stones with a single species or a few isolated strains under laboratory conditions. In the present work the authors present the development of a method for the determination of bioreceptivity, as well as a study of the bioreceptivity of selected natural stone versus the latter’s intrinsic properties. Field examples of biodeterioration are also presented. The study was supported by the Slovenian Research Agency (L1-5453).
B.06 Other
COBISS.SI-ID: 39328045In this expert article authors describe the most common mistakes and errors connected with stone construction. Previous construction mistakes such as erroneous wall finishing can lead to formation of thermal bridges which cause biosoiling and foauling.
F.17 Transfer of existing technologies, know-how, methods and procedures into practice
COBISS.SI-ID: 2174311Nano-crystalline photocatalytic active titanium dioxide is one of the most investigated material over the past decade due to its useful properties, such as chemical stability and non-toxicity. TiO2 occurs in several crystalline modifications, the most interesting being anatase and rutile. Both modifications exhibit semiconducting properties of n-type with energy of forbidden band of 3.2 eV and 3.0 eV for anatase and rutile, respectively. Wide forbidden band restricts the use of TiO2 as a photocatalyst in the visible light spectrum. To increase activity various methods have been used, one of which is doping with different elements. It has been found that by varying the synthesis parameters (pH and addition of isopropanol) we can influence the structure and the functional properties of titanium dioxide. Low pH favors the formation of rutile, while at higher pH values a mixed phase of titanium oxide is formed. Addition of isopropanol also promotes the formation of rutile. By reducing the pH and the addition of isopropanol, we managed to prepare TiO2 with high photocatalytic activity, which is more than twice the activity of P25. The most photocatalytic active in our research has been rutile modification. Doping with nitrogen according to the described synthetic method does not significantly affect the photocatalytic activity of nano-TiO2.
F.18 Transfer of new know-how to direct users (seminars, fora, conferences)
COBISS.SI-ID: 1536231875