Bipolar Tribocharging Signal During Friction Force Fluctuations At Metal-insulator Interfaces.

Friction and triboelectrification of materials show a strong correlation during sliding contacts. Friction force fluctuations are always accompanied by two tribocharging events at metal-insulator [e.g., polytetrafluoroethylene (PTFE)] interfaces: injection of charged species from the metal into PTFE followed by the flow of charges from PTFE to the metal surface. Adhesion maps that were obtained by atomic force microscopy (AFM) show that the region of contact increases the pull-off force from 10 to 150 nN, reflecting on a resilient electrostatic adhesion between PTFE and the metallic surface. The reported results suggest that friction and triboelectrification have a common origin that must be associated with the occurrence of strong electrostatic interactions at the interface.

Graded Meshes In Bio-thermal Problems With Transmission-line Modeling Method.

In this study, the transmission-line modeling (TLM) applied to bio-thermal problems was improved by incorporating several novel computational techniques, which include application of graded meshes which resulted in 9 times faster in computational time and uses only a fraction (16%) of the computational resources used by regular meshes in analyzing heat flow through heterogeneous media. Graded meshes, unlike regular meshes, allow heat sources to be modeled in all segments of the mesh. A new boundary condition that considers thermal properties and thus resulting in a more realistic modeling of complex problems is introduced. Also, a new way of calculating an error parameter is introduced. The calculated temperatures between nodes were compared against the results obtained from the literature and agreed within less than 1% difference. It is reasonable, therefore, to conclude that the improved TLM model described herein has great potential in heat transfer of biological systems.

Crescimento e desempenho motor em pre-escolares de Itapira SP : um enfoque bio-social-cultural

Universidade Estadual de Campinas. Faculdade de Educação Física

Esporte e midia : interfaces e significados dos conteudos esportivos atribuidos pelos anlunos

Universidade Estadual de Campinas . Faculdade de Educação Física

Comparação dos estados nutricionais dos alunos do ensino medio da cidade de Los Angeles VIII. Região de Bio-Bio, Chile : (1991-2000)

Universidade Estadual de Campinas . Faculdade de Educação Física

As interfaces entre imagem corporal e a representação simbolica de Carl Gustav Jung

Universidade Estadual de Campinas . Faculdade de Educação Física

As diferentes interfaces da aventura na natureza : reflexões sobre a sociabilidade na vida contemporanea

Universidade Estadual de Campinas . Faculdade de Educação Física