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Castano, Belky P.,Ramirez, Vladimir,Cancelado, Julio A. Occupational Safety and Health Research Institute 2019 Safety and health at work Vol.10 No.3
Background: Painters in the automotive sector are routinely exposed to volatile organic solvents, and the levels vary depending on the occupational health and safety controls enforced at the companies. This study investigates the levels of exposure to organic vapors and the existence of controls in the formal economy sector in southern Colombia. Methods: This is an exploratory study of an observational and descriptive character. An analysis of solvents is conducted via the personal sampling of painters and the analysis of samples using the National Institute for Occupational Safety and Health 1501 method. The amount of solvents analyzed varied according to the budget allocated by the companies. The person in charge of the occupational safety and health management system was interviewed to learn about the exposure controls implemented at the companies. Results: A medium exposure risk for toluene was found in one company. Another presented medium risk for carbon tetrachloride, xylene, ethylbenzene, and n-butanol. The others showed low risk of exposure and that the controls implemented were not sufficient or efficient. Conclusion: These results shed light on the working conditions of these tradespeople. The permissible limits established by Colombian regulations for the evaluated chemical contaminants were not exceeded. However, there were contaminants that exceeded the limits of action. The analysis of findings made it possible to propose improvements in occupational safety and health management systems to allow the optimization of working conditions for painters, prevent the occurrence of occupational diseases, and reduce costs to the country's health system.
Quality monitoring of complex manufacturing systems on the basis of model driven approach
Fernando Castano,Rodolfo E. Haber,Wael M. Mohammed,Miroslaw Nejman,Alberto Villalonga,Jose L. Martinez Lastra 국제구조공학회 2020 Smart Structures and Systems, An International Jou Vol.26 No.4
Monitoring of complex processes faces several challenges mainly due to the lack of relevant sensory information or insufficient elaborated decision-making strategies. These challenges motivate researchers to adopt complex data processing and analysis in order to improve the process representation. This paper presents the development and implementation of quality monitoring framework based on a model-driven approach using embedded artificial intelligence strategies. In this work, the strategies are applied to the supervision of a microfabrication process aiming at showing the great performance of the framework in a very complex system in the manufacturing sector. The procedure involves two methods for modelling a representative quality variable, such as surface roughness. Firstly, the hybrid incremental modelling strategy is applied. Secondly, a generalized fuzzy clustering c-means method is developed. Finally, a comparative study of the behavior of the two models for predicting a quality indicator, represented by surface roughness of manufactured components, is presented for specific manufacturing process. The manufactured part used in this study is a critical structural aerospace component. In addition, the validation and testing are performed at laboratory and industrial levels, demonstrating proper real-time operation for non-linear processes with relatively fast dynamics. The results of this study are very promising in terms of computational efficiency and transfer of knowledge to manufacturing industry.
On the dynamics of contact line freezing of water droplets on superhydrophobic carbon soot coatings
Esmeryan Karekin D.,Castano Carlos E.,Gyoshev Stanislav D.,Lazarov Yuliyan,Stoimenov Nikolay I.,Mohammadi Reza 한국물리학회 2021 Current Applied Physics Vol.31 No.-
Despite the opportunity to manipulate the water freezing via superhydrophobic materials, their commercial use for passive icing protection is still questioned, since the combined effect of surface morphology, air cushion arrangement, roughness, chemistry and film thickness on the icephobic properties of a given non-wettable solid remains unexplored. This article addresses the existing research gaps by studying the ice nucleation dynamics at the contact line of various superhydrophobic soot-based surfaces, potentially applicable in cryobiology for enhancing the existing cryopreservation technologies. We examine the freezing time and freezing temperature of water droplets settled on three groups of soot coatings with divergent morphochemical features, adjusted by modifying the samples with alcohol, fluorocarbon and/or silver hydrogen fluoride. Our results demonstrate the appearance of a new “contour” freezing mode, where the droplet shell crystallizes simultaneously with the contact interface, whilst the soot’s chemical bonds along with some of its physical characteristics govern the ice formation.
( Alfredo Ceballos ),( Gladys Castano ),( Sarahi Mendoza ),( Juan Gonzalez ),( Rosa Mas ),( Lilia Fernandez ),( Jose Illnait ),( Meilis Mesa ),( Rafael Gamez ),( Julio Cesar Fernandez ),( Ricardo Tell 대한내과학회 2011 The Korean Journal of Internal Medicine Vol.26 No.2
Background/Aims: Increased osteoclast activity is a pivotal finding in osteoporosis. This increase is mediated via the mevalonate-to-cholesterol pathway, which is involved in producing the intermediates required for osteoclast activity. D-003, a mixture of high molecular weight sugarcane wax acids, has been shown to inhibit cholesterol synthesis prior to mevalonate production, resulting in a reduction of bone loss and resorption in ovariectomized rats. Moreover, previous studies have demonstrated that short-term D-003 treatment reduces urinary excretion of deoxypyridinoline/creatinine in postmenopausal women. Methods: We performed a double-blinded, placebo-controlled study to investigate the effects of D-003 (10 mg/day) treatment for 3 years on bone mineral density (BMD) in 83 postmenopausal women with low BMD. Results: Over 3 years, D-003 treatment increased lumbar spine BMD (5.1%, p < 0.01) and improved osteoporosis-related quality of life scores as compared with placebo-treated controls. D-003 was also well tolerated; the frequency of adverse events in the bone, joints, or muscle with D-003 treatment (p < 0.05) was lower than in the placebo group. Conclusions: D-003 treatment (10 mg/day) for 3 years increased lumbar spine BMD and produced clinical improvements in postmenopausal women with low BMD. Further studies, however, will be required to confirm these results. (Korean J Intern Med 2011;26:168-178)
F. Stobiecki,T. Luciński,J. Dubowik,B. Szymański,M. Urbaniak,F. J. Castano,T. Stobiecki 한국자기학회 1998 Journal of Magnetics Vol.3 No.3
The magnetisation behaviour of polycrystalline permalloy/copper multilayers with mixed antiferromagnetic/ferromagnetic coupling was investigated as function of temperature. The results are discussed in a framework of a realistic model of anitferromagnetically coupled layers connected by ferromagnetic pinholes. A microstructure of pinholes (their density and dimensions) was varied either by a proper annealing treatment or by choosing samples with various Cu spacer thicknesses. It was demonstrated that the temperature changes of the net magnetic moment measured in a magnetic field smaller than the saturation field was strongly affected by the composition of the pinholes, their density, cross-sectional area and their lengths.