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Papers by Costa Neto
Arquivos Brasileiros de Oftalmologia, 2009
Propriedades biomecânicas locais em uma córnea modelada usando elementos finitos prevê surgimento... more Propriedades biomecânicas locais em uma córnea modelada usando elementos finitos prevê surgimento de ceratocone
A dynamic analysis of a rail passenger car study was performed in order to evaluate the differenc... more A dynamic analysis of a rail passenger car study was performed in order to evaluate the differences between a secondary air suspension bogie with three-point and a four-point control system. Dynamical analyses with different conditions of turning radius and velocities were performed and the L/V coefficients were calculated. The results have shown that there was not a best configuration for all conditions of velocities. The magnitudes of the L/V coefficients in the three-point configuration depend on the direction of the movement of the rail car. The four-point configuration showed an intermediate performance in all velocities. The best performance could be achieved with the development of a switch system that changes the configuration of the three-point system according to the direction of movement and velocity of the rail passenger car.
Arquivos brasileiros de …, Jan 1, 2009
PURPOSE: The ability to predict and understand which biomechanical properties of the cornea are r... more PURPOSE: The ability to predict and understand which biomechanical properties of the cornea are responsible for the stability or progression of keratoconus may be an important clinical and surgical tool for the eye-care professional. We have developed a finite element model of the cornea, that tries to predicts keratoconus-like behavior and its evolution based on material properties of the corneal tissue. METHODS: Corneal material properties were modeled using bibliographic data and corneal topography was based on literature values from a schematic eye model. Commercial software was used to simulate mechanical and surface properties when the cornea was subject to different local parameters, such as elasticity. RESULTS: The simulation has shown that, depending on the corneal initial surface shape, changes in local material properties and also different intraocular pressures values induce a localized protuberance and increase in curvature when compared to the remaining portion of the cornea. CONCLUSIONS: This technique provides a quantitative and accurate approach to the problem of understanding the biomechanical nature of keratoconus. The implemented model has shown that changes in local material properties of the cornea and intraocular pressure are intrinsically related to keratoconus pathology and its shape/curvature.
A dynamic analysis of a rail passenger car study was performed in order to evaluate the differenc... more A dynamic analysis of a rail passenger car study was performed in order to evaluate the differences between a secondary air suspension bogie with three-point and a four-point control system. Dynamical analyses with different conditions of turning radius and velocities were performed and the L/V coefficients were calculated. The results have shown that there was not a best configuration for all conditions of velocities. The magnitudes of the L/V coefficients in the three-point configuration depend on the direction of the movement of the rail car. The fourpoint configuration showed an intermediate performance in all velocities. The best performance could be achieved with the development of a switch system that changes the configuration of the three-point system according to the direction of movement and velocity of the rail passenger car.
Arquivos Brasileiros de Oftalmologia, 2009
Propriedades biomecânicas locais em uma córnea modelada usando elementos finitos prevê surgimento... more Propriedades biomecânicas locais em uma córnea modelada usando elementos finitos prevê surgimento de ceratocone
A dynamic analysis of a rail passenger car study was performed in order to evaluate the differenc... more A dynamic analysis of a rail passenger car study was performed in order to evaluate the differences between a secondary air suspension bogie with three-point and a four-point control system. Dynamical analyses with different conditions of turning radius and velocities were performed and the L/V coefficients were calculated. The results have shown that there was not a best configuration for all conditions of velocities. The magnitudes of the L/V coefficients in the three-point configuration depend on the direction of the movement of the rail car. The four-point configuration showed an intermediate performance in all velocities. The best performance could be achieved with the development of a switch system that changes the configuration of the three-point system according to the direction of movement and velocity of the rail passenger car.
Arquivos brasileiros de …, Jan 1, 2009
PURPOSE: The ability to predict and understand which biomechanical properties of the cornea are r... more PURPOSE: The ability to predict and understand which biomechanical properties of the cornea are responsible for the stability or progression of keratoconus may be an important clinical and surgical tool for the eye-care professional. We have developed a finite element model of the cornea, that tries to predicts keratoconus-like behavior and its evolution based on material properties of the corneal tissue. METHODS: Corneal material properties were modeled using bibliographic data and corneal topography was based on literature values from a schematic eye model. Commercial software was used to simulate mechanical and surface properties when the cornea was subject to different local parameters, such as elasticity. RESULTS: The simulation has shown that, depending on the corneal initial surface shape, changes in local material properties and also different intraocular pressures values induce a localized protuberance and increase in curvature when compared to the remaining portion of the cornea. CONCLUSIONS: This technique provides a quantitative and accurate approach to the problem of understanding the biomechanical nature of keratoconus. The implemented model has shown that changes in local material properties of the cornea and intraocular pressure are intrinsically related to keratoconus pathology and its shape/curvature.
A dynamic analysis of a rail passenger car study was performed in order to evaluate the differenc... more A dynamic analysis of a rail passenger car study was performed in order to evaluate the differences between a secondary air suspension bogie with three-point and a four-point control system. Dynamical analyses with different conditions of turning radius and velocities were performed and the L/V coefficients were calculated. The results have shown that there was not a best configuration for all conditions of velocities. The magnitudes of the L/V coefficients in the three-point configuration depend on the direction of the movement of the rail car. The fourpoint configuration showed an intermediate performance in all velocities. The best performance could be achieved with the development of a switch system that changes the configuration of the three-point system according to the direction of movement and velocity of the rail passenger car.