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Avaliação dos fatores de risco biomecânicos presentes na atividade ocupacional de eletricistas
(Universidade Federal de São Carlos, 2011-10-24) Castro, Cristiane Shinohara Moriguchi de; Coury, Helenice Jane Cote Gil
Electrical energy is an essential good that may affect people s life and the economy. Overhead line workers and construction electricians are the workers responsible for the availability of this good. To perform their occupational tasks these workers are exposed to fatal accidents and musculoskeletal overload. Although of high rates of accidents and musculoskeletal injuries among these workers, few studies evaluated the presence of risk factors in the occupational settings of line workers and electricians. In this sense, it is necessary to identify the risk factors in the electricians activities (Study 1), quantify the exposure using valid direct methods (Study 2, 3 and 5) and verify the importance of the found results for clinical applications (Study 4 and 5). Study 1 was developed to determine the prevalence of musculoskeletal symptoms among line workers and to identify the risk factors for musculoskeletal disorders. The results of this study showed postural overload and high prevalence of musculoskeletal symptoms at shoulders and neck. Based on these results, Study 2 was purposed to quantify the postural overload in the five main tasks performed by line workers. Loading and unloading the ladder on the vehicle support was deeply investigated by means of posture and force measurements in Study 3, due its higher frequency in line workers schedule. Postures and movements were recorded by four inclinometer sensors at a sampling rate of 20Hz. Inclinometer sensors were previously calibrated and them attached at workers head, upper back and right and left upper arms. Study 2 and 3 identified that line workers are exposed to shoulder and neck awkward postures during all evaluated tasks. However, both studies were performed in simulated settings. By this way, Study 4 was developed to verify if the postures recorded in the simulated conditions are representative of the posture recorded in occupational environment. The results of Study 4 showed that whether the tasks are possible to be reproduced in simulated conditions the postural overload is representative of occupational overload. Besides the representativeness, Study 5 focused the comparison between posture exposure among Brazilian and Norwegian electricians to verify whether the same job type evaluated by the same method under the same procedures would present the same overload disregard the culture differences. The results of this study would allow inferring about external validity of the recordings. According to the found results, Brazilian and Norwegian posture exposure is similar. The results of Study 5 also indicated the high postural overload that these workers are submitted. Therefore, the present thesis showed the need for ergonomic interventions to reduce biomechanical risk factors presented at electricians work activity and the representativeness of the found results to occupational environmental conditions and to other populations.
Tendência de formação de fase amorfa em ligas a base de magnésio para biomaterial temporário
(Universidade Federal de São Carlos, 2011-10-24) Danez, Gabriela Pancev; Botta Filho, Walter José; https://lattes.cnpq.br/8956458007749112; https://lattes.cnpq.br/8137234680727325
Mg alloys have attracted attention as potential implant material because of their good mechanical properties, biocompatibility and biodegradation properties. However corrosion of these alloys causes intense release of hydrogen gas which is not desirable for biomedical applications. Zberg et. al. reported a significant reduction in hydrogen evolution in Mg-Zn-Ca glassy alloys due the increase of Zn without the formation of undesirable intermetallic phases. These glassy alloys showed great potential for deployment in a new generation of biodegradable implants. In this context the evaluation of the glass forming ability (GFA) of Mg-Zn-Ca alloys, in the Mg-rich composition corner is relevant. In the present work we studied Mg-rich compositions in the Mg-Zn-Ca system based on the topological instability criterion (min) combined with the average electronegativity difference (e) among the elements in the alloy. Bulk samples were produced by rapid cooling in a copper mold and ribbons were produced by melt-spinning technique. The microstructure, amorphous nature, thermal properties and chemical composition of samples were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and electron dispersive spectroscopy (EDS). Best results were observed in alloys with Ca content limited to 6 at%. Furthermore, the samples ewre subjected to oxidation and high change in composition.