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Abstract Introduction : The Mexican manufacturing sector in the automotive industry employs an average of 8 million 850 thousand workers per year spread across the 32 states, of which Puebla contributes with 465106, developing, in a high percentage, the verification of new parts as part of the manufacture process. This activity is supported by the use of devices known as fixtures, whose equipment and tool forces operators to lift loads between 10 and 50 kilograms by performing manual operations to hold parts, presenting pain at the lumbar level, therefore, it is essential to measure the risks of back injuries in the study population. The objective was to identify and measure the risks of back injuries in the study population. Materials and Methods : The inspection process is analyzed by identifying the potential risk factors. Ergonomic methodologies and instruments are used, such as Quick Exposure Check (QEC), the National Institute for Occupational Safety and Health (NIOSH) equation, the REBA (Rapid Entire Body Assessment) method, Ovako's Work Posture Analysis System (OWAS), among others. Results : The QEC method shows that trunk/back and wrist/hand are the most sensitive parts to risk exposure, indicating that 18 % of the postures are rated 4 in the level of risk, with the back rotated and bent in over 32 % of time. The weight of the operation exceeds 20 kilograms in 71.4 %. Conclusion: Four ergonomic techniques are used to assess the risk of injury, the inspection process of manufactured parts is analyzed.
Resumen Introducción: la industria manufacturera mexicana del ramo automotor emplea en promedio 8 millones 850 mil trabajadores al año repartidos en los 32 estados, de los cuales Puebla contribuye con 465106, desarrollando, en un alto porcentaje, la verificación de piezas nuevas como parte de los procesos de manufactura. Esta actividad se apoya en el uso de dispositivos conocidos como fixtures, cuyo equipo y herramienta obliga a los operarios a levantar cargas entre los 10 y los 50 kilogramos, realizando operaciones manuales para la sujeción de piezas, presentándose dolores a nivel lumbar, por lo que es primordial medir los riesgos de lesiones en la espalda de la población en estudio. El objetivo fue identificar y medir los riesgos de lesiones en la espalda de la población en estudio. Materiales y métodos : se analiza el proceso de inspección identificando los factores de riesgo potencial. Se utilizan metodologías y herramientas ergonómicas, tales como Quick Exposure Check (QEC), la ecuación del National Institute for Occupational Safety and Health (NIOSH), el método REBA (Rapid Entire Body Assessment), el sistema de análisis de posturas de trabajo de Ovako (OWAS), entre otras. Resultados : el método QEC muestra que tronco/ espalda y muñeca/mano son las partes más sensibles a la exposición de riesgo, señalando el 18 % de las posturas en un nivel de riesgo 4, con la espalda rotada y flexionada en más del 32 % del tiempo. El peso que conlleva la operación supera los 20 kilogramos en el 71,4%. Conclusión : se utilizan cuatro técnicas ergonómicas para evaluar el riesgo de lesión y se analiza el proceso de inspección de piezas fabricadas.
Resumo Introdução : a indústria manufatureira mexicana do ramo automotivo emprega em média 8 milhões 850 mil trabalhadores ao ano repartidos nos 32 estados, dos quais Puebla contribui com 465106 deles, desenvolvendo, em uma alta porcentagem a verificação de peças novas como parte dos processos de manufatura. Esta atividade apoia-se no uso de dispositivos conhecidos como fixtures, cuja equipe e ferramentas abriga aos operários a levantar cargas entre os 10 e 50 quilogramas realizando operações manuais para a fixação de peças, se apresentando dores no nível lombar, pelo que é primordial medir os riscos de lesões nas costas da população em estudo. Materiais e métodos : se analisa o processo de inspeção identificando os fatores de risco potencial. Se utilizam metodologias e ferramentas ergonómicas, tais como Quick Exposure Check (QEC), a equação do National Institute for Occupational Safety and Health (NIOSH), o método REBA (Rapid Entire Body Assessment), o sistema de análise de posturas de trabalho de Ovako (OWAS), entre outras. Resultados : o método QEC mostra que o torso/costas e o pulso/mão são as partes mais sensíveis à exposição de risco, assinalando o 18 % das posturas em um nível de risco 4, com as costas rotadas e curvadas em mais do 32 % do tempo. O peso que leva a operação supera os 20 quilogramas no 71.4 %. Conclusão : utilizam-se quatro técnicas ergonómicas para avaliar o risco de lesão e se analisa o processo de inspeção de peças fabricadas.
Assuntos
Humanos , Lesões nas Costas , Controle de Qualidade , Gestão de Riscos , Saúde Ocupacional , Ergonomia , MéxicoRESUMO
Automatic visual inspection allows for the identification of surface defects in manufactured parts. Nevertheless, when defects are on a sub-millimeter scale, detection and recognition are a challenge. This is particularly true when the defect generates topological deformations that are not shown with strong contrast in the 2D image. In this paper, we present a method for recognizing surface defects in 3D point clouds. Firstly, we propose a novel 3D local descriptor called the Model Point Feature Histogram (MPFH) for defect detection. Our descriptor is inspired from earlier descriptors such as the Point Feature Histogram (PFH). To construct the MPFH descriptor, the models that best fit the local surface and their normal vectors are estimated. For each surface model, its contribution weight to the formation of the surface region is calculated and from the relative difference between models of the same region a histogram is generated representing the underlying surface changes. Secondly, through a classification stage, the points on the surface are labeled according to five types of primitives and the defect is detected. Thirdly, the connected components of primitives are projected to a plane, forming a 2D image. Finally, 2D geometrical features are extracted and by a support vector machine, the defects are recognized. The database used is composed of 3D simulated surfaces and 3D reconstructions of defects in welding, artificial teeth, indentations in materials, ceramics and 3D models of defects. The quantitative and qualitative results showed that the proposed method of description is robust to noise and the scale factor, and it is sufficiently discriminative for detecting some surface defects. The performance evaluation of the proposed method was performed for a classification task of the 3D point cloud in primitives, reporting an accuracy of 95%, which is higher than for other state-of-art descriptors. The rate of recognition of defects was close to 94%.
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This paper describes the development and validation of a new multivariate calibration method based on diffuse reflectance mid infrared spectroscopy for direct and simultaneous determination of three veterinary pharmaceutical drugs, pyrantel pamoate, praziquantel and febantel, in commercial tablets. The best synergy interval partial least squares (siPLS) model was obtained by selecting three spectral regions, 3715-3150, 2865-2583, and 2298-1733 cm(-1), preprocessed by first derivative and Savitzky-Golay smoothing followed by mean centering. This model was built with five latent variables and provided root mean square errors of prediction (RMSEP) equal or lower than 0.69 mg per 100 mg of powder for the three analytes. The method was validated according the appropriate regulations through the estimate of figures of merit, such as trueness, precision, linearity, analytical sensitivity, bias and residual prediction deviation (RPD). Then, it was applied to three different veterinary pharmaceutical formulations found in the Brazilian market, in a situation of multi-product calibration, since the excipient composition of these commercial products, which was not known a priori, was modeled by an experimental design that scanned the likely content range of the possible constituents. The results were verified with high performance liquid chromatography with diode array detection (HPLC-DAD) and high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) and were in agreement with the predicted values at 95% confidence level. The developed method presented the advantages of being simple, rapid, solvent free, and about ten times faster than the HPLC ones.