UPM（芬欧汇川集团）是芬兰最大，也是世界最大的造纸企业之一，拥有上百年的发展历史，1996年被列入《世界遗产目录》的韦尔拉磨木和纸板厂（Verla Ground—wood and Board Mill）就隶属于UPM。作为专业从事森林工业的现代化企业，UPM...UPM（芬欧汇川集团）是芬兰最大，也是世界最大的造纸企业之一，拥有上百年的发展历史，1996年被列入《世界遗产目录》的韦尔拉磨木和纸板厂（Verla Ground—wood and Board Mill）就隶属于UPM。作为专业从事森林工业的现代化企业，UPM在14个国家建有生产企业，芬欧汇川（常熟）纸业有限公司建立于上世纪90年代，现在年产能达N80万吨，主要生产印刷用纸和办公用纸。展开更多
Races using kitefoil and windfoil surfboards have been in the Olympic Games for the first time in Paris 2024,signalling their relevance in sailing sports.However,the dynamics of these devices is yet not well understoo...Races using kitefoil and windfoil surfboards have been in the Olympic Games for the first time in Paris 2024,signalling their relevance in sailing sports.However,the dynamics of these devices is yet not well understood,in particular the influence on the hydrodynamic forces and moments of the distance of the foil to the free surface.Considering this,the present paper documents an experimental investigation in which forces and torque produced,under uniform flow,by a full-scale state-of-the-art hydrofoil(suitable both for kitesurf and windsurf)were measured.A range of velocities,angles of attack,and submergences were tested,leading to Froude numbers based on submergence with maximum values around five,a typical range in actual sailing conditions.From these tests,formulae for the hydrodynamic coefficients have been proposed.They can be used for developing Velocity Prediction Programs(VPP)for this kind of craft,a necessary tool to plan racing configurations and to analyze their racing performance.With the aim of making the experimental data useful for benchmarking numerical models and for future research on related topics such as foil ventilation and transition to turbulence,the specimen’s 3D file is provided as supplementary material to this paper.展开更多
This review highlights the performance enhancement of polyvinyl alcohol(PVA)composites through the incorporation of nanofillers,focusing on mechanical,thermal,electrical and piezoelectric improvements.It examines bio-...This review highlights the performance enhancement of polyvinyl alcohol(PVA)composites through the incorporation of nanofillers,focusing on mechanical,thermal,electrical and piezoelectric improvements.It examines bio-based fillers such as nanocellulose cellulose nanofibrils(CNF)and cellulose nanocrystals(CNC),and carbon-based fillers like graphene nanoplatelets(GNP)and carbon nanotubes(CNT).CNF and CNC increase tensile strength by up to 40%and 17.9%,respectively,due to their ability to reinforce polymer networks.CNC also improves thermal stability,raising degradation temperatures to approximately 327℃through enhanced hydrogen bonding.Electrical and piezoelectric properties are significantly improved,with dielectric behaviour enhanced by up to 107%and open-circuit voltage reaching 25.6 V,suitable for energy harvesting.GNP and CNT contribute by forming conductive networks within the PVA matrix,enabling superior electrical conductivity and consistent piezoresistive responses under strain.These characteristics make such composites ideal for applications in flexible electronics,sensors,structural health monitoring and other advanced fields.This synthesis of experimental results and critical insights underscores the broad utility and future potential of nanofillerenhanced PVA composites across aerospace,automotive,healthcare,and defence sectors.展开更多
文摘UPM（芬欧汇川集团）是芬兰最大，也是世界最大的造纸企业之一，拥有上百年的发展历史，1996年被列入《世界遗产目录》的韦尔拉磨木和纸板厂（Verla Ground—wood and Board Mill）就隶属于UPM。作为专业从事森林工业的现代化企业，UPM在14个国家建有生产企业，芬欧汇川（常熟）纸业有限公司建立于上世纪90年代，现在年产能达N80万吨，主要生产印刷用纸和办公用纸。
文摘Races using kitefoil and windfoil surfboards have been in the Olympic Games for the first time in Paris 2024,signalling their relevance in sailing sports.However,the dynamics of these devices is yet not well understood,in particular the influence on the hydrodynamic forces and moments of the distance of the foil to the free surface.Considering this,the present paper documents an experimental investigation in which forces and torque produced,under uniform flow,by a full-scale state-of-the-art hydrofoil(suitable both for kitesurf and windsurf)were measured.A range of velocities,angles of attack,and submergences were tested,leading to Froude numbers based on submergence with maximum values around five,a typical range in actual sailing conditions.From these tests,formulae for the hydrodynamic coefficients have been proposed.They can be used for developing Velocity Prediction Programs(VPP)for this kind of craft,a necessary tool to plan racing configurations and to analyze their racing performance.With the aim of making the experimental data useful for benchmarking numerical models and for future research on related topics such as foil ventilation and transition to turbulence,the specimen’s 3D file is provided as supplementary material to this paper.
基金Ministry of Higher Education Malaysia(MoHE)and Universiti Putra Malaysia under the Fundamental Research Grant Scheme(FRGS)(Grant Nos.FRGS/1/2023/TK09/UPM/01/3 and 5540599。
文摘This review highlights the performance enhancement of polyvinyl alcohol(PVA)composites through the incorporation of nanofillers,focusing on mechanical,thermal,electrical and piezoelectric improvements.It examines bio-based fillers such as nanocellulose cellulose nanofibrils(CNF)and cellulose nanocrystals(CNC),and carbon-based fillers like graphene nanoplatelets(GNP)and carbon nanotubes(CNT).CNF and CNC increase tensile strength by up to 40%and 17.9%,respectively,due to their ability to reinforce polymer networks.CNC also improves thermal stability,raising degradation temperatures to approximately 327℃through enhanced hydrogen bonding.Electrical and piezoelectric properties are significantly improved,with dielectric behaviour enhanced by up to 107%and open-circuit voltage reaching 25.6 V,suitable for energy harvesting.GNP and CNT contribute by forming conductive networks within the PVA matrix,enabling superior electrical conductivity and consistent piezoresistive responses under strain.These characteristics make such composites ideal for applications in flexible electronics,sensors,structural health monitoring and other advanced fields.This synthesis of experimental results and critical insights underscores the broad utility and future potential of nanofillerenhanced PVA composites across aerospace,automotive,healthcare,and defence sectors.
