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Papers by Marcos dos Santos Dantas

Fibers and Polymers, 2021

Natural fibre-based composites have been investigated as a viable ecological alternative to conve... more Natural fibre-based composites have been investigated as a viable ecological alternative to conventional materials, combining low-cost and sustainable features to engineering products. In tropical countries, such as Brazil, there are many lignocellulosic residues that are discarded in nature, polluting the environment, such as the Tucumã fruit, which generates about 50 tonnes/month of solid waste only in the city of Manaus (State of Amazonas). This work investigates a novel wood-plastic composite (WPC) made from recycled polypropylene (PP) and Tucumã endocarp powder (TEP) without coupling agents that encompasses social and environmental issues. WPCs are composed of 10, 20, 30, 40 and 50 wt% of TEP combined with PP by injection moulding, being characterised by SEM, FTIR, flammability, water absorption, ageing, tensile, compressive, three-point bending, impact and scratch tests. TEP does not react to the matrix phase, presenting 49.4 % and 37.4 % of cellulose and lignin, respectively. In general, the incorporation of TEP not only increases the elastic modulus and the dynamic friction coefficient, but also reduces the strength and the burning rate of WPCs. WPC preserves its physical integrity after ageing, absorbing up to 1.6 % of water. Composites made with 20 wt% of TEP can be considered promising materials to be used as wood plastic for sustainable engineering applications.

Applied Surface Science, 2011

Titanium nitride (TiN) films were deposited by the D.C. magnetron sputtering process on a SUS 304... more Titanium nitride (TiN) films were deposited by the D.C. magnetron sputtering process on a SUS 304 steel substrate. The effect of postdeposition annealing on the microstructure and mechanical properties of thin TiN films was studied in detail using atomic force microscopy, a potentiostat and nano-indentation tests. The TiN films were annealed at temperatures ranging from 100 to 300°C. Surface roughnesses of TiN films estimated by atomic force microscopy decreased from 3.83 to 2.43 nm as the annealing temperatures increased from 100 to 300°C. The corrosion rates of the films measured by a potentionstat in a 0.5-molar H 2 SO 4 solution decreased from 8. 57 10 2 ×to 4. 59 10 2 ×-mmPY as the annealing temperatures increased from 100 to 300°C. An increase in corrosion resistance was attributed to an increase in hardness and a modulus of the film with the annealing temperature. Atomic force microscopy images of the film revealed fine-grained morphology for TiN films annealed at higher temperature. Experimental results show that the mechanical properties of TiN films could be significantly improved by annealing. The control of the annealing process was proved to be critical for the improvement of TiN film properties.

This work show what the students of mechanical engineer need to project equipments using MEF and ... more This work show what the students of mechanical engineer need to project equipments using MEF and softwares for design.

Fibers and Polymers, 2021

Natural fibre-based composites have been investigated as a viable ecological alternative to conve... more Natural fibre-based composites have been investigated as a viable ecological alternative to conventional materials, combining low-cost and sustainable features to engineering products. In tropical countries, such as Brazil, there are many lignocellulosic residues that are discarded in nature, polluting the environment, such as the Tucumã fruit, which generates about 50 tonnes/month of solid waste only in the city of Manaus (State of Amazonas). This work investigates a novel woodplastic composite (WPC) made from recycled polypropylene (PP) and Tucumã endocarp powder (TEP) without coupling agents that encompasses social and environmental issues. WPCs are composed of 10, 20, 30, 40 and 50 wt% of TEP combined with PP by injection moulding, being characterised by SEM, FTIR, flammability, water absorption, ageing, tensile, compressive, three-point bending, impact and scratch tests. TEP does not react to the matrix phase, presenting 49.4 % and 37.4 % of cellulose and lignin, respectively. ...

Materials Research, 2021

The properties of aluminum alloys can be improved by the processing conditions that cause changes... more The properties of aluminum alloys can be improved by the processing conditions that cause changes in the microstructure and by the addition of alloy elements. In order to understand the physical behavior and mechanical properties of aluminum alloys, it is important to be aware of some of the microstructural characteristics. Some of these characteristics are the morphology, alloy elements, volume and size, and second phase. In this study, we analyzed the effect of annealing on the mechanical and microstructural properties of the laminated AA 5182 aluminum alloy, when subjected to different annealing conditions. The alloy was heated to temperatures of 50º C, 100º C, 150º C, 200º C, 250º C and 300º C for 10 minutes and left to cool naturally. The evolution of the microstructure was characterized by optical and electronic microscopy with EDS, and, to obtain the mechanical properties, a tensile test was performed and the fractures were subsequently analyzed. The results showed that the heat treatment used reduced the amount of second phase particles and this influenced the mechanical properties.

This work show what the students of mechanical engineer need to project equipments using MEF and ... more This work show what the students of mechanical engineer need to project equipments using MEF and softwares for design.

Fibers and Polymers, 2021

Natural fibre-based composites have been investigated as a viable ecological alternative to conve... more Natural fibre-based composites have been investigated as a viable ecological alternative to conventional materials, combining low-cost and sustainable features to engineering products. In tropical countries, such as Brazil, there are many lignocellulosic residues that are discarded in nature, polluting the environment, such as the Tucumã fruit, which generates about 50 tonnes/month of solid waste only in the city of Manaus (State of Amazonas). This work investigates a novel wood-plastic composite (WPC) made from recycled polypropylene (PP) and Tucumã endocarp powder (TEP) without coupling agents that encompasses social and environmental issues. WPCs are composed of 10, 20, 30, 40 and 50 wt% of TEP combined with PP by injection moulding, being characterised by SEM, FTIR, flammability, water absorption, ageing, tensile, compressive, three-point bending, impact and scratch tests. TEP does not react to the matrix phase, presenting 49.4 % and 37.4 % of cellulose and lignin, respectively. In general, the incorporation of TEP not only increases the elastic modulus and the dynamic friction coefficient, but also reduces the strength and the burning rate of WPCs. WPC preserves its physical integrity after ageing, absorbing up to 1.6 % of water. Composites made with 20 wt% of TEP can be considered promising materials to be used as wood plastic for sustainable engineering applications.

Applied Surface Science, 2011

Titanium nitride (TiN) films were deposited by the D.C. magnetron sputtering process on a SUS 304... more Titanium nitride (TiN) films were deposited by the D.C. magnetron sputtering process on a SUS 304 steel substrate. The effect of postdeposition annealing on the microstructure and mechanical properties of thin TiN films was studied in detail using atomic force microscopy, a potentiostat and nano-indentation tests. The TiN films were annealed at temperatures ranging from 100 to 300°C. Surface roughnesses of TiN films estimated by atomic force microscopy decreased from 3.83 to 2.43 nm as the annealing temperatures increased from 100 to 300°C. The corrosion rates of the films measured by a potentionstat in a 0.5-molar H 2 SO 4 solution decreased from 8. 57 10 2 ×to 4. 59 10 2 ×-mmPY as the annealing temperatures increased from 100 to 300°C. An increase in corrosion resistance was attributed to an increase in hardness and a modulus of the film with the annealing temperature. Atomic force microscopy images of the film revealed fine-grained morphology for TiN films annealed at higher temperature. Experimental results show that the mechanical properties of TiN films could be significantly improved by annealing. The control of the annealing process was proved to be critical for the improvement of TiN film properties.

This work show what the students of mechanical engineer need to project equipments using MEF and ... more This work show what the students of mechanical engineer need to project equipments using MEF and softwares for design.

Fibers and Polymers, 2021

Natural fibre-based composites have been investigated as a viable ecological alternative to conve... more Natural fibre-based composites have been investigated as a viable ecological alternative to conventional materials, combining low-cost and sustainable features to engineering products. In tropical countries, such as Brazil, there are many lignocellulosic residues that are discarded in nature, polluting the environment, such as the Tucumã fruit, which generates about 50 tonnes/month of solid waste only in the city of Manaus (State of Amazonas). This work investigates a novel woodplastic composite (WPC) made from recycled polypropylene (PP) and Tucumã endocarp powder (TEP) without coupling agents that encompasses social and environmental issues. WPCs are composed of 10, 20, 30, 40 and 50 wt% of TEP combined with PP by injection moulding, being characterised by SEM, FTIR, flammability, water absorption, ageing, tensile, compressive, three-point bending, impact and scratch tests. TEP does not react to the matrix phase, presenting 49.4 % and 37.4 % of cellulose and lignin, respectively. ...

Materials Research, 2021

The properties of aluminum alloys can be improved by the processing conditions that cause changes... more The properties of aluminum alloys can be improved by the processing conditions that cause changes in the microstructure and by the addition of alloy elements. In order to understand the physical behavior and mechanical properties of aluminum alloys, it is important to be aware of some of the microstructural characteristics. Some of these characteristics are the morphology, alloy elements, volume and size, and second phase. In this study, we analyzed the effect of annealing on the mechanical and microstructural properties of the laminated AA 5182 aluminum alloy, when subjected to different annealing conditions. The alloy was heated to temperatures of 50º C, 100º C, 150º C, 200º C, 250º C and 300º C for 10 minutes and left to cool naturally. The evolution of the microstructure was characterized by optical and electronic microscopy with EDS, and, to obtain the mechanical properties, a tensile test was performed and the fractures were subsequently analyzed. The results showed that the heat treatment used reduced the amount of second phase particles and this influenced the mechanical properties.

This work show what the students of mechanical engineer need to project equipments using MEF and ... more This work show what the students of mechanical engineer need to project equipments using MEF and softwares for design.