Aguas del Iténez o Guaporé

Bolivia y Brasil comparten una de las cuencas más atractivas y preservadas de la te-giuri amazônica: la cuenca del rio llénez o Guaporé, que escurre tanto sobre el lecho rocoso del Escudo Precámbrico Brasilefto como sobre las Hanuras del Beni. Estas influencias hacen que la cuenca del iténez tenga una elevada heterogeneidad de habitats, una fauna acuálica peculiar y un alto valor de conservation. Este patrimo­nio binacional posée un potencial importante para la conservación de la diversidad regional y cl dcsar rollo sostcniblc participativo de las comunidades locales. El libro contiene un resumen del conotimìento de la cuenca y sus recursos, generado en los últimos 10 anos por un equipo de investigadores bolivianos, brasilefios y de otras nacionalidades. Se presenta una descripeión del medio fisico, así como resultados relevantes sobre la biodiversidad acuática, con énfasis en algas, peces, reptiles y mamíferos. El aporte más notable del libro, adernas de la descripeión ecológica del ecosistema, son las lecciones aprendidas que surgieron de experiências locales sobre la élaboration participativa de herramientas para la gestion de los recursos hidrobiológicos.A Bolívia e o Brasil compartilham uma das bacias hidrográficas mais atrativas e preservadas da região amazônica: a bacia do Rio Iténez ou Guaporé. A combinação das influências do escudo pré-cambriano brasileiro e da planícies do Beni é uma das razões pela qual existem na região elevada heterogeneidade de habitats, fauna aquática peculiar e alto grau valor dc conservação. Eslc patrimônio binacional possui potencial significativo para a conservação da diversidade regional e desenvolvimento sustentável participativo das comunidades locais. O livro contém um resumo do conhecimento da bacia e seus recursos, gerado nos últimos dez anos por uma equipe de pesquisadores bolivianos, brasileiros e de outras nacionalidades. Apresentamos uma descrição do meio físico, bem como resultados relevantes da biodiversidade aquática, com ênfase em algas, peixes, répteis e mamíferos. A contribuição mais notável do livro, além da descrição ecológica do ecossistema, é a descrição das lições aprendidas que surgiram a partir de experiências locais sobre elaboração participativa de ferramentas para a gestão dos recursos aquáticos presentes nesta bacia

Enhanced composite thermal conductivity by percolated networks of in-situ confined-grown carbon nanotubes

Acknowledgements: This work was partially supported by the National Key R&D Program of China (Nos. 2018YFA0208402 and 2020YFA0714700), the National Natural Science Foundation of China (Nos. 52172060, 51820105002, 11634014, and 51372269), Magna International, and EPSRC project “Advanced Nanotube Application and Manufacturing (ANAM) Initiative” (No. EP/M015211/1). The authors especially thank Mr. David Paul, Ms. Mingzhao Wang, Ms. Rulan Qiao, and Dr. Sarah Stevenson, for their kind support and useful discussion.Despite the ever-increasing demand of nanofillers for thermal enhancement of polymer composites with higher thermal conductivity and irregular geometry, nanomaterials like carbon nanotubes (CNTs) have been constrained by the nonuniform dispersion and difficulty in constructing effective three-dimensional (3D) conduction network with low loading and desired isotropic or anisotropic (specific preferred heat conduction) performances. Herein, we illustrated the in-situ construction of CNT based 3D heat conduction networks with different directional performances. First, to in-situ construct an isotropic percolated conduction network, with spherical cores as support materials, we developed a confined-growth technique for CNT-core sea urchin (CNTSU) materials. With 21.0 wt.% CNTSU loading, the thermal conductivity of composites reached 1.43 ± 0.13 W/(m·K). Secondly, with aligned hexagonal boron nitride (hBN) as an anisotropic support, we constructed CNT-hBN aligned networks by in-situ CNT growth, which improved the utilization efficiency of high density hBN and reduced the thermal interface resistance between matrix and fillers. With ~ 8.5 wt.% loading, the composites possess thermal conductivity up to 0.86 ± 0.14 W/(m·K), 374% of that for neat matrix. Due to the uniformity of CNTs in hBN network, the synergistic thermal enhancement from one-dimensional (1D) + two-dimensional (2D) hybrid materials becomes more distinct. Based on the detailed experimental evidence, the importance of purposeful production of a uniformly interconnected heat conduction 3D network with desired directional performance can be observed, particularly compared with the traditional direct-mixing method. This study opens new possibilities for the preparation of high-power-density electronics packaging and interfacial materials when both directional thermal performance and complex composite geometry are simultaneously required

Enhanced composite thermal conductivity by percolated networks of in-situ confined-grown carbon nanotubes

Despite the ever-increasing demand of nanofillers for thermal enhancement of polymer composites with higher thermal conductivity and irregular geometry, nanomaterials like carbon nanotubes (CNTs) have been constrained by the nonuniform dispersion and difficulty in constructing effective 3D conduction network with low loading and desired isotropic or anisotropic (specific preferred heat conduction) performances. Herein, we illustrated the in-situ construction of CNT based 3D heat conduction networks with different directional performances. First, to in-situ construct an isotropic percolated conduction network, with spherical cores as support materials, we developed a confined-growth technique for CNT-core sea urchins (CNTSU) materials. With 21.0 wt% CNTSU loading, the thermal conductivity of composites reached 1.43±0.13 W/(m•K). Secondly, with aligned hexagonal boron nitride (hBN) as an anisotropic support, we constructed CNT-hBN aligned networks by in-situ CNT growth, which improved the utilization efficiency of high density hBN and reduced the thermal interface resistance between matrix and fillers. With ~8.5 wt% loading, the composites possess thermal conductivity up to 0.86±0.14 W/(m•K), 374% of that for neat matrix. Due to the uniformity of CNTs in hBN network, the synergistic thermal enhancement from 1D+2D hybrid materials becomes more distinct. Based on the detailed experimental evidence, the importance of purposeful production of a uniformly interconnected heat conduction 3D network with desired directional performance can be observed, particularly compared with the traditional direct-mixing method. This study opens new possibilities for the preparation of high-power-density electronics packaging and interfacial materials when both directional thermal performance and complex composite geometry are simultaneously required.EPSRC EP/M015211/

Enhanced composite thermal conductivity by percolated networks of in-situ confined-grown carbon nanotubes

Abstract Despite the ever-increasing demand of nanofillers for thermal enhancement of polymer composites with higher thermal conductivity and irregular geometry, nanomaterials like carbon nanotubes (CNTs) have been constrained by the nonuniform dispersion and difficulty in constructing effective three-dimensional (3D) conduction network with low loading and desired isotropic or anisotropic (specific preferred heat conduction) performances. Herein, we illustrated the in-situ construction of CNT based 3D heat conduction networks with different directional performances. First, to in-situ construct an isotropic percolated conduction network, with spherical cores as support materials, we developed a confined-growth technique for CNT-core sea urchin (CNTSU) materials. With 21.0 wt.% CNTSU loading, the thermal conductivity of composites reached 1.43 ± 0.13 W/(m·K). Secondly, with aligned hexagonal boron nitride (hBN) as an anisotropic support, we constructed CNT-hBN aligned networks by in-situ CNT growth, which improved the utilization efficiency of high density hBN and reduced the thermal interface resistance between matrix and fillers. With ~ 8.5 wt.% loading, the composites possess thermal conductivity up to 0.86 ± 0.14 W/(m·K), 374% of that for neat matrix. Due to the uniformity of CNTs in hBN network, the synergistic thermal enhancement from one-dimensional (1D) + two-dimensional (2D) hybrid materials becomes more distinct. Based on the detailed experimental evidence, the importance of purposeful production of a uniformly interconnected heat conduction 3D network with desired directional performance can be observed, particularly compared with the traditional direct-mixing method. This study opens new possibilities for the preparation of high-power-density electronics packaging and interfacial materials when both directional thermal performance and complex composite geometry are simultaneously required