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
目的对空心螺钉与重建钢板固定耻骨联合分离的生物力学性能进行测试,为临床应用提供理论依据。方法取温州医学院防腐正常成人骨盆标本15具,随机分成3组。自第5腰椎水平及双大腿中上2/3处将尸体横断。耻骨联合处切开,并将单侧骶棘韧带、...目的对空心螺钉与重建钢板固定耻骨联合分离的生物力学性能进行测试,为临床应用提供理论依据。方法取温州医学院防腐正常成人骨盆标本15具,随机分成3组。自第5腰椎水平及双大腿中上2/3处将尸体横断。耻骨联合处切开,并将单侧骶棘韧带、骶结节韧带、骶髂前韧带切断,模拟Tile B1型骨盆骨折,依次分别采用5孔重建钢板和6.5 mm空心螺钉内固定治疗耻骨联合分离。将标本固定于生物力学试验机,在腰5椎体上方对其进行垂直轴向压缩生物力学测试,最大负荷达400 N,比较耻骨联合分离的位移程度。结果 3.5 mm 5孔重建钢板和空心螺钉固定,均可显著减少耻骨联合的分离,恢复骨盆环的力学稳定性。其中3.5 mm 5孔重建钢板加4枚皮质骨螺钉于耻骨联合上方固定组,耻骨联合位移为(0.944±0.983)mm,空心螺钉髓内固定组耻骨联合分离为(-0.03±0.378)mm,两者之间存在统计学显著性差异(P<0.05)。结论空心螺钉在生物力学稳定性上优于5孔3.5 mm重建钢板。空心螺钉具有良好的生物力学性能,固定可靠,符合生物学固定的原则。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.
文摘目的对空心螺钉与重建钢板固定耻骨联合分离的生物力学性能进行测试,为临床应用提供理论依据。方法取温州医学院防腐正常成人骨盆标本15具,随机分成3组。自第5腰椎水平及双大腿中上2/3处将尸体横断。耻骨联合处切开,并将单侧骶棘韧带、骶结节韧带、骶髂前韧带切断,模拟Tile B1型骨盆骨折,依次分别采用5孔重建钢板和6.5 mm空心螺钉内固定治疗耻骨联合分离。将标本固定于生物力学试验机,在腰5椎体上方对其进行垂直轴向压缩生物力学测试,最大负荷达400 N,比较耻骨联合分离的位移程度。结果 3.5 mm 5孔重建钢板和空心螺钉固定,均可显著减少耻骨联合的分离,恢复骨盆环的力学稳定性。其中3.5 mm 5孔重建钢板加4枚皮质骨螺钉于耻骨联合上方固定组,耻骨联合位移为(0.944±0.983)mm,空心螺钉髓内固定组耻骨联合分离为(-0.03±0.378)mm,两者之间存在统计学显著性差异(P<0.05)。结论空心螺钉在生物力学稳定性上优于5孔3.5 mm重建钢板。空心螺钉具有良好的生物力学性能,固定可靠,符合生物学固定的原则。
