This article is devoted to the thermophysical and mechanical study of an eco-material, poto-poto. The objective is to study the influence of the addition of bamboo fibers on the thermophysical properties of the materi...This article is devoted to the thermophysical and mechanical study of an eco-material, poto-poto. The objective is to study the influence of the addition of bamboo fibers on the thermophysical properties of the material, while verifying that it complies with the mechanical standards in Cameroon. A double study is therefore carried out: a mechanical characterization whose objective is to determine the mechanical properties (compressive strength, flexural strength and Young’s modulus) and a thermophysical characterization whose objective is to determine the thermal conductivity. For the thermophysical characterization, the asymmetric hot plane experimental setup based on 1D quadrupole modelling was developed and simulated for the estimation of thermal effusivity E and volume heat capacity ρCp. The obtained experimental results show that the apparent thermal conductivity of the developed materials decreases with increasing fibers. Although the reference material (0% fibers) has a much higher conductivity than the ordinary sand block (1.15 Wm<sup>-1</sup> K<sup>-1</sup>), the addition of fibers, already at 2%, contributes to decrease this conductivity (0.95 Wm<sup>-1</sup> K<sup>-1</sup>). From the point of view of thermal insulation and energy savings, the thermal conductivity results obtained show that the use of these materials with a maximum fibercontent of 6% would be a better thermal insulator than sand block or compressed earth brick. The compressive strength obtained is such that Rc > 0.6 MPa. All the materials developed meet the design standards when used as infill.展开更多
This paper studies a model of energy harvester that consists of an electromechanical pendulum system subjected to nonlinear springs. The output power is analyzed in terms of the intrinsic parameters of the device lead...This paper studies a model of energy harvester that consists of an electromechanical pendulum system subjected to nonlinear springs. The output power is analyzed in terms of the intrinsic parameters of the device leading to optimal parameters for energy harvesting. It is found that in an appropriate range of the springs constant, the power attains higher values as compared to the case without springs. The dynamical behavior of the device shows transition to chaos.展开更多
文摘This article is devoted to the thermophysical and mechanical study of an eco-material, poto-poto. The objective is to study the influence of the addition of bamboo fibers on the thermophysical properties of the material, while verifying that it complies with the mechanical standards in Cameroon. A double study is therefore carried out: a mechanical characterization whose objective is to determine the mechanical properties (compressive strength, flexural strength and Young’s modulus) and a thermophysical characterization whose objective is to determine the thermal conductivity. For the thermophysical characterization, the asymmetric hot plane experimental setup based on 1D quadrupole modelling was developed and simulated for the estimation of thermal effusivity E and volume heat capacity ρCp. The obtained experimental results show that the apparent thermal conductivity of the developed materials decreases with increasing fibers. Although the reference material (0% fibers) has a much higher conductivity than the ordinary sand block (1.15 Wm<sup>-1</sup> K<sup>-1</sup>), the addition of fibers, already at 2%, contributes to decrease this conductivity (0.95 Wm<sup>-1</sup> K<sup>-1</sup>). From the point of view of thermal insulation and energy savings, the thermal conductivity results obtained show that the use of these materials with a maximum fibercontent of 6% would be a better thermal insulator than sand block or compressed earth brick. The compressive strength obtained is such that Rc > 0.6 MPa. All the materials developed meet the design standards when used as infill.
文摘This paper studies a model of energy harvester that consists of an electromechanical pendulum system subjected to nonlinear springs. The output power is analyzed in terms of the intrinsic parameters of the device leading to optimal parameters for energy harvesting. It is found that in an appropriate range of the springs constant, the power attains higher values as compared to the case without springs. The dynamical behavior of the device shows transition to chaos.
