Medidas de concentração de radônio proveniente de argamassas de cimento portland, gesso e fosfogesso

Portland cement being very common construction material has in its composition the natural gypsum. To decrease the costs of manufacturing, the cement industry is substituting the gypsum in its composition by small quantities of phosphogypsum, which is the residue generated by the production of fertilizers and consists essentially of calcium dihydrate and some impurities, such as fluoride, metals in general, and radionuclides. Currently, tons of phosphogypsum are stored in the open air near the fertilizer industries, causing contamination of the environment. The 226 Ra present in these materials, when undergoes radioactive decay, produces the 222Rn gas. This radioactive gas, when inhaled together with its decay products deposited in the lungs, produces the exposure to radiation and can be a potential cause of lung cancer. Thus, the objective of this study was to measure the concentration levels of 222Rn from cylindrical samples of Portland cement, gypsum and phosphogypsum mortar from the state of Paraná, as well as characterizer the material and estimate the radon concentration in an environment of hypothetical dwelling with walls covered by such materials. Experimental setup of 222Rn activity measurements was based on AlphaGUARD detector (Saphymo GmbH). The qualitative and quantitative analysis was performed by gamma spectrometry and EDXRF with Au and Ag targets tubes (AMPTEK), and Mo target (ARTAX) and mechanical testing with x- ray equipment (Gilardoni) and the mechanical press (EMIC). Obtained average values of radon activity from studied materials in the air of containers were of 854 ± 23 Bq/m3, 60,0 ± 7,2 Bq/m3 e 52,9 ± 5,4 Bq/m3 for Portland cement, gypsum and phosphogypsum mortar, respectively. These results extrapolated into the volume of hypothetical dwelling of 36 m3 with the walls covered by such materials were of 3366 ± 91 Bq/m3, 237 ± 28 Bq/m3 e 208 ± 21 Bq/m3for Portland cement, gypsum and phosphogypsum mortar, respectively. Considering the limit of 300 Bq/m3 established by the ICRP, it could be concluded that the use of Portland cement plaster in dwellings is not secure and requires some specific mitigation procedure. Using the results of gamma spectrometry there were calculated the values of radium equivalent activity concentrations (Raeq) for Portland cement, gypsum and phosphogypsum mortar, which were obtained equal to 78,2 ± 0,9 Bq/kg; 58,2 ± 0,9 Bq/kg e 68,2 ± 0,9 Bq/kg, respectively. All values of radium equivalent activity concentrations for studied samples are below the maximum level of 370 Bq/kg. The qualitative and quantitative analysis of EDXRF spectra obtained with studied mortar samples allowed to evaluate quantitate and the elements that constitute the material such as Ca, S, Fe, and others.

A narrativa histórica de Alexandre Wollner sobre o design brasileiro em sua relação com arte, indústria e tecnologia

This work aims to investigate the historical narratives in which the graphic designer Alexandre Wollner assembled about the development of its own profession in Brazil, focusing the ways in which his discourse points relations among design (with greater emphasis in graphic design) and visual arts, the industrial development and notions about technology. Firstly, the theoretical setup searched for dialogues with design historians, with Mikhail Bakhtin, specially his concepts about “ideology” and “discourse’, and the theory of Field Autonomy by Pierre Bourdieu applied in the artistic practice. Following, the relation between Wollner’s own journey and the Brazilian industrial development is shown, and, at last, three of his historical texts are studied, which are written in different moments (1964; 1983; 1998), being those in which the analyzed author wished to point out the origens, events and names that are more remarkable. Throughout the work, it is pointed the importance of Wollner’s contact with the modernist european ideologies that share an abstract and rationalist matrix found at Hochschule für Gestaltung Ulm (HfG Ulm), the german design school from the city of Ulm, in the 1950s. Such modernist discourse understood the practice of design as a method with scientific character, being then different of some other more recurring artistic professional practices in some productive sectors. Wollner aimed to apply such ideals in his professional practice, being the foundation of the paulista office forminform, in 1958, one of his first expressions of such posture, and in his academic practice, helping the foundation of the Escola Superior de Desenho Industrial (ESDI), in Rio de Janeiro, in 1963. Such modernist ideals went along with moments of the Brazilian industrial development during the government of Juscelino Kubitschek (1956–1961) and the “Economical Miracle” from the military government (1968–1973). Wollner argued about the need for the development of national design as a technological and productive differential that would help the growth of national industry, based on Ulm’s project model concept. It is defended that Wollner’s professional and intelectual path, in his efforts of thinking a history of Brazilian design through the choice of pioneers in the area, was founded on an “ideal model” of design, leaving aside the modernist experiences from the 1950s. Such posture would indicate a search for validation of his own profession that was beginning to become more evident in Brazilian productive means, aiming the creation of a differential space in comparison with pre-established practices, usually link to graphic artists from the time.