Transporte de partículas com autopropulsão em substratos 2d ordenados

Detalhes bibliográficos
Ano de defesa: 2015
Autor(a) principal: Borba, André Duarte
Orientador(a): Não Informado pela instituição
Banca de defesa: Não Informado pela instituição
Tipo de documento: Dissertação
Tipo de acesso: Acesso aberto
Idioma: por
Instituição de defesa: Não Informado pela instituição
Programa de Pós-Graduação: Não Informado pela instituição
Departamento: Não Informado pela instituição
País: Não Informado pela instituição
Palavras-chave em Português:
Link de acesso: http://www.repositorio.ufc.br/handle/riufc/11280
Resumo: Self-propelled particles are those that use their internal energy to generate movement. The term is originally associated with the model introduced by T. Vicsek et al.[Phys. Rev. Lett. 75, 1226 (1995)] that identifies a dynamic transition associated to the collective movement of "individuals" of the same species. Examples of SPP occur in natural systems such as microorganisms (bacteria, viruses, and protozoa) or artificially as in the case of colloidal particles suitably prepared. The study of SPP is important in many fields such as materials engineering, medicine and basic sciences (physics and chemistry). In general, the collective motion reveals a dramatically different behavior as compared to the characteristics motion of individual components of a given system. That is, the action of a given individual is dominated by the presence of the other components as a result of the interaction between them. Thus, it is important to understand the collective behavior of SPP. In this dissertation, we study a two-dimensional SPP system subject to an external force and in the presence of rigid obstacles with anisotropic geometry (semi-circle) orderly distributed in the form of a square lattice. In addition to the interaction between particles and between particles and obstacles, the individual movement of each SPP is influenced by a white noise. The objective is to characterize the transport of SPP in a 2D substrate in the absenceand in the presence of a driving external force. We present a systematic study of the collective motion of the SPP as a function of noise intensity, which defines the erratic movement of the SPP, the size of the obstacles, the SPP density and separation between the obstacles. Due to the presence of anisotropic obstacles, there is a spontaneous collective movement and ordered in a given preferential direction, characterized by the non-zero average velocity of SPP in the absence of the external force. The basic conditions for the spontaneous ordered collective movement are: low-intensity noise ( << 1 ) and SPP density greater than a given critical value.