Restauração do pavilhão, cúpula metálica e luneta equatorial de 32 cm: conjunto arquitetônico do Museu de Astronomia e Ciências Afins (MAST)

MAST is a science and technology museum located in the grounds and architectural\ud complex belonging to the former Observatório Nacional in Rio de Janeiro. This complex, concluded\ud in 1921, comprises of 16 buildings, and was listed by the Artistic and Historic National (1986)\ud and State (1987) Heritage. This complex features three pavilions sheltering the equatorial\ud telescopes, typical examples of Architecture and Engineering buildings for Astronomic purposes.\ud Two of these pavilions, all of which are under the care of MAST, shelter the 21 cm and 32 cm\ud telescopes, plus a third, part of the National Observatory, which houses the 46 cm equatorial\ud telescope. The present study is the result of the work undertaken by MAST to preserve and restore\ud the historical buildings under its responsibility. Thanks to a partnership set up with the Vitae\ud Foundation, it has been possible to develop restoration work covering all aspects of the pavilions\ud (moving metal dome, building, scientific instrument), as well as the areas museography, with a\ud view to informing visitors about the restoration work undertaken. The project, based on the\ud historical research on the complex, was carried out by a multidisciplinary team over two years.\ud Each stage of the work was comprehensively photographed, including the intervention project\ud design, which was based on architectural surveys and the diagnosis of the complexs state of\ud repair, plus the restoration per se. This is a groundbreaking initiative in Latin America and will\ud serve as an example for future actions to be taken on historical buildings, especially those built\ud for scientific and technological purposes

Using the acoustic sound pressure level for quality prediction of surfaces created by abrasive waterjet

The paper deals with an innovative way of cutting materials by abrasive waterjet with a view to increase its quality. In the research work, we were concerned with the search for a relationship between surface roughness and noise in the abrasive waterjet cutting process. Innovation lies in the use of negative characteristic of the technology—noise, which is a carrier of information about the quality of cutting process. In this way, the noise can be positively used in the on-line control of the technological process. The final result is a project for control of the process of abrasive waterjet cutting of materials by means of feedback according to the on-line measurement of acoustic pressure level L aeq (dB). Instantaneous information about the state of cut according to the instantaneous value of L aeq amplitude allows the automatic regulation of traverse speed of cutting head v p (mm.min−1), which is, together with the pressure p (MPa), one of the most important technological factors of control of production technology from the point of view of economic indicators and qualitative indicators of a semiproduct. The proposed model has been experimentally verified and was simulated in Matlab