Loading...
6 results
Search Results
Now showing 1 - 6 of 6
- 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.
- 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.
- 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.
- Assessment and control of nanoparticles exposure in welding operations by use of a control banding toolPublication . Albuquerque, Paula Cristina; Gomes, João; Pereira, C. A.; Miranda, Rosa M.This paper describes the use of a Control Banding Tool to assess and further control of exposure of nanoparticles emitted during welding operations. The tool was applied to Metal Active Gas (MAG) arc welding of mild and stainless steel, providing semi-quantitative data on the process, so that protection measures could be derived, e.g. exhaust gas ventilation by hoods, local ventilation devices and containment measures. This tool is quite useful to compare and evaluate the characteristics of arc welding procedures so that more eco-friendly processes could be preferred over the more potentially noxious ones.
- 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.