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- Evaluation of the amount of nanoparticles emitted in LASER additive manufacture/weldingPublication . Gomes, J. F.; Miranda, R.; Oliveira, J. P.; Esteves, H. M.; Albuquerque, PaulaObjectives: The objective of this study was the evaluation of the professional exposure to nanoparticles during tasks performed in workstations for production of metallic parts by laser welding additive manufacturing. Materials and methods: The study was developed in an installed additive manufacturing machine, having controlled temperature and humidity in an industrial unit where metal parts were being produced using stainless steel powders of granulometry of 10 to 35 μm. Results and discussion: Monitoring of airborne nanoparticles emission was made using adequate equipment, which showed considerable number of nanoparticles over the baseline, having the same composition as the steel powder used. Conclusion: It is concluded that the values of professional exposure to nanoparticles are high in these workstations and that the nanoparticles to which the workers are exposed are small in size (around 15 nm), thus having a strong capacity for alveolar penetration and, consequently, with a strong possibility of passing to the bloodstream, accumulating in the body.
- Evaluation of the amount of nanoparticles emitted in welding fume from stainless steel using different shielding gasesPublication . Pacheco, Rita; Gomes, João; Miranda, R.; Quintino, M. L.The primary objective of this study was to correlate the emission of macro and nanoparticles released during the process of metal inert gas/metal active gas (MIG/MAG) of stainless steel with different gas mixtures. Using different gas mixtures with different heat inputs, it was possible to determine fume formation rates and surface areas of nanoparticles with alveolar lung deposition capacity. It was found, how the various transfer modes and the type of gas protection, in particular, the percentage of active elements in the in the chemical composition of the gas, affect the amount of fumes generated and also the generation of nanoparticles with a high capacity of deposition. The spray transfer mode always shows higher values of nanoparticles surface area, unlike the fume formation rates. Among the tested mixtures 82%Ar+18%CO2 generates higher emissions of nanoparticles as well as fume formation rates.
- Characterization of airborne emission of nanoparticles in the ceramic industry in PortugalPublication . Esteves, Hélder; Bordado, J.; Gomes, João; Miranda, R.; Albuquerque, PaulaThe objective of this study was to evaluate occupational exposure to nanoparticles during some tasks performed in different production processes of different ceramic industries in Portugal, to select the places of greatest occupational exposure through the analysis of the sampled data, to verify what is the pulmonary accumulation in these places, to identify the composition of the released nanoparticles, apply a Control Banding Tool and try to understand which companies require more risk control measures. The study was carried out in three different national ceramics production industries, one for sanitary ceramics production, another for porcelain crockery production and finally another for the production of ornamental crockery (red paste). It is concluded that occupational exposure values to nanoparticles are high in all cases and that nanoparticles are very small in size (11.5 to 15.4 nm). Existing risk control measures are insufficient and verified risk levels are high (Risk Level 3 and 4). The chemical composition of the analyzed nanoparticles is similar regardless of the typology of the ceramic production plant and their chemical composition as a percentage of certain materials has a direct influence on crystallinity.
- Exposição profissional a nanopartículas na fabricação de peças por soldadura a laserPublication . Esteves, H.; Gomes, João; Miranda, R.; Albuquerque, PaulaA soldadura é o principal processo industrial utilizado para unir metais. Contudo, pode produzir fumos nocivos para a saúde dos trabalhadores e estima-se que, presentemente, 1-2% de trabalhadores (cerca de mais de 3 milhões), estejam sujeitos à ação de fumos e gases de soldadura. Os riscos inerentes aos processos de soldadura podem ser classificados como riscos decorrentes de agentes físicos e riscos relacionados com os componentes químicos. Por outro lado, as propriedades físicas e químicas dos fumos e os fatores individuais dos trabalhadores são fatores preponderantes na deposição de partículas inaladas. No entanto, ainda existem incertezas sobre o papel das partículas finas e ultrafinas (nanopartículas) em relação a outros poluentes atmosféricos que causam efeitos adversos para a saúde. A nível dos processos de soldadura, diversos autores demonstraram um aumento da incidência de doenças respiratórias de quatro vezes na incidência de asma entre soldadores dos Estados Unidos da América (EUA) em relação à população geral, e um aumento de duas vezes na capacidade de resposta das vias aéreas em soldadores versus não-soldadores no mesmo ambiente de trabalho. A exposição a fumos de soldadura no corpo humano pode despoletar o aparecimento de efeitos diferentes dependendo da composição desses fumos. Algumas dessas composições têm efeitos a curto prazo, tais como a designada “febre do soldador”. Contudo, os fumos de soldadura podem provocam efeitos a longo prazo nomeadamente: irritação da pele, irritação do trato respiratório, lesões nos rins e fígado, efeitos dermatológicos, doenças pulmonares do tipo asmáticas; efeitos crónicos que incluem cancro (nariz, laringe, pulmão). Estas situações de exposição profissional são de elevada complexidade e envolvem a componente inerente ao indivíduo, às condições de trabalho e à atividade desenvolvida sendo necessário aplicar uma abordagem integrada no processo de diagnóstico, avaliação e gestão do risco, adaptada a cada situação específica.
- Evaluation of the amount of nanoparticles emitted in LASER additive manufacture/weldingPublication . Gomes, João; Miranda, R.; P. Oliveira, J.; Esteves, Helder; Albuquerque, PaulaObjectives: The objective of this study was the evaluation of the professional exposure to nanoparticles during tasks performed in workstations for production of metallic parts by laser welding additive manufacturing.Materials and methods: The study was developed in an installed additive manufacturing machine, having controlled temperature and humidity in an industrial unit where metal parts were being produced using stainless steel powders of granulometry of 10 to 35m.Results and discussion: Monitoring of airborne nanoparticles emission was made using adequate equipment, which showed considerable number of nanoparticles over the baseline, having the same composition as the steel powder used.Conclusion: It is concluded that the values of professional exposure to nanoparticles are high in these workstations and that the nanoparticles to which the workers are exposed are small in size (around 15nm), thus having a strong capacity for alveolar penetration and, consequently, with a strong possibility of passing to the bloodstream, accumulating in the body.
- Determination of “safe” and “critical” nanoparticles exposure to welders in a workshopPublication . Gomes, João; Miranda, R.The present study examined consequences of “safe” versus “critical” exposure to nanoparticles (NP) released during welding operations. With this aim in mind, a set of measurements regarding NP emissions was undertaken in a workshop during welding by metal active gas of carbon steel using different mixtures of argon (Ar) and carbon dioxide (CO2) as well as different process parameters which might influence emission of (NP). If these measurements were conducted in several locations away from the welding sources, the graphical representation of the obtained observations with time enabled definition of “safe” and “critical” regions within a welding workshop in terms of welder’s exposure. This information may be combined with the results of risk analysis derived by control banding and helps to categorize the sites where regulatory measures such as operation containment or dedicated exhaust ventilation need to be implemented.
- Characterization of airborne emission of nanoparticles in the ceramic industry in PortugalPublication . Esteves, H.; Bordado, J.; Gomes, João; Miranda, R.; Albuquerque, PaulaThe objective of this study was to evaluate occupational exposure to nanoparticles during some tasks performed in different production processes of different ceramic industries in Portugal, to select the places of greatest occupational exposure through the analysis of the sampled data, to verify what is the pulmonary accumulation in these places, to identify the composition of the released nanoparticles, apply a Control Banding Tool and try to understand which companies require more risk control measures. The study was carried out in three different national ceramics production industries, one for sanitary ceramics production, another for porcelain crockery production, and finally another for the production of ornamental crockery (red paste). It is concluded that occupational exposure values to nanoparticles are high in all cases and that nanoparticles are very small in size (11.5 to 15.4 nm). Existing risk control measures are insufficient and verified risk levels are high (Risk Level 3 and 4). The chemical composition of the analyzed nanoparticles is similar regardless of the typology of the ceramic production plant and their chemical composition as a percentage of certain materials has a direct influence on crystallinity.