Climatic changes and the increased air pollution intensify the atmospheric degradation of stone, affecting the aspect and integrity of valuable historical buildings constructed using limestone and located in tropical coastal sites. This paper analyzes limestone degradation process due to air pollution and humidity in tropical humid conditions in historical buildings located in the cities of Havana, Cuba and San Francisco de Campeche, Mexico. Havana shows higher pollution level than San Francisco de Campeche, which presents pollution levels as a consequence of a multipollutant situation along with the presence of airborne salinity. Temperature and humidity data were recorded from the walls of historical buildings in the city of Havana: the Minor Basilica and the convent of San Francisco. Changes in dry/wet cycles due to the absence of direct sun radiation as well as a high level of SO 2 allow the formation of a black crust (mainly composed of gypsum) in the lower part of the surface of the facade of the Basilica Minor in Havana; however, crusts formed in historical buildings located in San Francisco de Campeche City are mainly composed of calcium carbonate, indicating the importance of natural degradation mechanisms mainly due to dissolution in water. In the last case, the influence of water plays an important role in the development of biodegradation, which induces the formation of calcium oxalates. Caves and cracks were found in the walls of military buildings caused by water infiltration. The influence of air contamination, humidity, and construction materials determine the type of degradation that historical buildings undergo.

We present a new bibliometric approach to identify research groups in a particular research field. With a combination of bibliometric mapping techniques and network analysis we identify and classify clusters of authors to represent research groups. In this paper we illustrate the application and potential of this approach and present two types of outcomes: actual research groups and potential research groups. The former enables us to define research groups beyond the organizational structure. The latter may be used to identify potential partners for collaboration. Our approach is a starting point to deal with the complex issue of research groups in a changing structure of scientific research.

Atmospheric corrosion level in tropical coastal zones is usually very significant.Corrosion control and preservation of infrastructure in these regions is very important to increase durability. Atmospheric corrosion of carbon steel, copper, galvanized steel, and aluminum was evaluated in a coastal industrial port zone located in a tropical island during 1 year. Samples were exposed at seven outdoor corrosion sites located at different distances from the sea. Main atmospheric pollutants, relative humidity, and air temperature were monitored during the exposure time. The existence of a combination between two of the most aggressive atmosphere types was determined (coastal-industrial and industrial-coastal). Changes in RH and temperature influenced 1462 |

Abstract. Atmospheric corrosion is important to consider for energy production and transmission. Important and valuable information have been accumulated in this subject; however, the application of new knowledge obtained is not completed. In order to contribute to a decrease in economic losses caused by atmospheric corrosion in wind farms, studies toward application of this knowledge should be carried out. One of the most common reasons for the failure of coastal structures and infrastructures is deterioration failure which is the result of structure deterioration and lack of project maintenance. Atmospheric corrosion was evaluated at outdoor and indoor exposure sites located at different distances from the sea in a wind farm region. Carbon and galvanized steel, copper and aluminum specimens were exposed. Main pollutants and atmospheric parameters were measured. Significant differences between outdoor corrosivity determined by dose response functions established on ISO standard respecting direct weight loss evaluation were found. Estimation carried out using dose response functions overestimate corrosivity (excepting copper). Main factors causing outdoor corrosion are different to indoor. Very high outdoor and indoor corrosivity classifications were determined.

Since their construction, these buildings have been exposed to the action of environmental agents that induce their deterioration. For long time, natural parameters like high relative humidity, extended rainfall periods and the effects of marine aerosols were the principal factors related with buildings degradation (Zendri, 2001, Cardell et al., 2003. Karstification, crust formation, lost of components and biodegradation are typical pathologies of degradation observed in the buildings. Nevertheless, in the last decade, the City has been under a dynamic development. As a consequence, a sensible increase in automobile units has been registered in specific areas of the city, including the historical centre.