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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.
- Assessment of airborne nanoparticles emissions in the ceramic industryPublication . Esteves, H.; Gomes, João; M. Miranda, R.; Albuquerque, P.The aim of this study was to evaluate the occupational exposure to nanoparticles during the tasks performed in various jobs in the production processes of the national ceramic industry, analyze the collected data and seek to understand the specific occupational exposure situation of the workers in this sector. The study was developed in three different national production plants of ceramic, one of sanitary production, another of refractory bricks and another of ornamental ware (red paste). It is concluded that the values of occupational exposure to nanoparticles are high in all cases and that the nanoparticles are of very small size, with a strong capacity for alveolar penetration and, consequently, with a strong possibility of passing into the bloodstream, accumulating in the body.
- 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.
- Study on the emission of nanoparticles from metal cleaning operations using laser technologiesPublication . Esteves, H.; Gomes, João; M. Miranda, R.; Albuquerque, P.; Viana, M.; de la Fuente, G. F.; Angurel, L.The aim of this study was to evaluate the occupational exposure of metal (aluminum, steel and titanium) cleaning with two types of LASERS (Laboratory Ablation LASER (LAL) and Diode) incisions with different intensities, different speeds, different incision times and different distances between lines in the samples, in order to be able to compare the resulting emissions for the different operative conditions. It is concluded that the number of nanoparticles measured with the probes inside the extraction are generally higher for all types of materials processed during this study; and that the number of nanoparticles are larger when compared with the number of nanoparticles released at the typical occupational level. The type of laser in question, its intensity, speed, incision time and line spacing affect the release of nanoparticles both in terms of the total number of nanoparticles released and in their size.
- 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.