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
A pump operating as a turbine(PAT)is a type of hydraulic machine capable of functioning both as a pump and as a turbine by reversing the flow direction.The pump-as-turbine(PAT)approach presents an effective method of ...A pump operating as a turbine(PAT)is a type of hydraulic machine capable of functioning both as a pump and as a turbine by reversing the flow direction.The pump-as-turbine(PAT)approach presents an effective method of hydropower generation,particularly suitable for addressing the increasing global energy demands in rural and remote areas.In addition to its adaptability,PAT-based micro-hydropower systems typically incur lower operating costs than conventional hydrodynamic turbines,despite requiring higher initial investment.Recent research has focused on integrating PATs into pipe distribution systems to harness untapped hydraulic energy.This study presents the development and performance evaluation of a novel pump operating as a turbine(PAT)impeller,designed to enhance hydropower recovery in water distribution systems.A three-dimensional(3D)impeller model was created using Catia software,integrating airfoil(hydrofoil)geometries into the blade profile to improve the efficiency of power extraction during turbine operation.Unlike conventional designs,the new impeller configuration generates additional force components aligned with the rotor’s direction of rotation,thereby increasing the moment about the axis and enhancing angular velocity.Computational fluid dynamics(CFD)simulations performed in ANSYS Fluent confirmed that the redesigned PAT significantly improves both performance and efficiency,demonstrating superior power recovery compared to the original design.The results highlight the potential of integrating PAT systems with optimized blade geometries into water distribution networks,offering a viable solution for energy recovery and head reduction during periods of low demand.展开更多
Graphene nanoplatelets(GNPs)have attracted tremendous interest due to their unique properties and bonding capabilities.This study focuses on the effect of GNP dispersion on the mechanical,thermal,and morphological beh...Graphene nanoplatelets(GNPs)have attracted tremendous interest due to their unique properties and bonding capabilities.This study focuses on the effect of GNP dispersion on the mechanical,thermal,and morphological behavior of GNP/epoxy nanocomposites.This study aims to understand how the dispersion of GNPs affects the properties of epoxy nanocomposite and to identify the best dispersion approach for improving mechanical performance.A solvent mixing technique that includes mechanical stirring and ultrasonication was used for producing the nanocomposites.Fourier transform infrared spectroscopy was used to investigate the interaction between GNPs and the epoxy matrix.The measurements of density and moisture content were used to confirm that GNPs were successfully incorporated into the nanocomposite.The findings showed that GNPs are successfully dispersed in the epoxy matrix by combining mechanical stirring and ultrasonication in a single step,producing well-dispersed nanocomposites with improved mechanical properties.Particularly,the nanocomposites at a low GNP loading of 0.1 wt%,demonstrate superior mechanical strength,as shown by increased tensile properties,including improved Young's modulus(1.86 GPa),strength(57.31 MPa),and elongation at break(4.98).The nanocomposite with 0.25 wt%GNP loading performs better,according to the viscoelastic analysis and flexural properties(113.18 MPa).Except for the nanocomposite with a 0.5 wt%GNP loading,which has a higher thermal breakdown temperature,the thermal characteristics do not significantly alter.The effective dispersion of GNPs in the epoxy matrix and low agglomeration is confirmed by the morphological characterization.The findings help with filler selection and identifying the best dispersion approach,which improves mechanical performance.The effective integration of GNPs and their interaction with the epoxy matrix provides the doorway for additional investigation and the development of sophisticated nanocomposites.In fields like aerospace,automotive,and electronics where higher mechanical performance and functionality are required,GNPs'improved mechanical properties and successful dispersion present exciting potential.展开更多
Accurate time synchronization is fundamental to the correct and efficient operation of Wireless Sensor Networks(WSNs),especially in security-critical,time-sensitive applications.However,most existing protocols degrade...Accurate time synchronization is fundamental to the correct and efficient operation of Wireless Sensor Networks(WSNs),especially in security-critical,time-sensitive applications.However,most existing protocols degrade substantially under malicious interference.We introduce iSTSP,an Intelligent and Secure Time Synchronization Protocol that implements a four-stage defense pipeline to ensure robust,precise synchronization even in hostile environments:(1)trust preprocessing that filters node participation using behavioral trust scoring;(2)anomaly isolation employing a lightweight autoencoder to detect and excise malicious nodes in real time;(3)reliability-weighted consensus that prioritizes high-trust nodes during time aggregation;and(4)convergence-optimized synchronization that dynamically adjusts parameters using theoretical stability bounds.We provide rigorous convergence analysis including a closed-form expression for convergence time,and validate the protocol through both simulations and realworld experiments on a controlled 16-node testbed.Under Sybil attacks with five malicious nodes within this testbed,iSTSP maintains synchronization error increases under 12%and achieves a rapid convergence.Compared to state-ofthe-art protocols like TPSN,SE-FTSP,and MMAR-CTS,iSTSP offers 60%faster detection,broader threat coverage,and more than 7 times lower synchronization error,with a modest 9.3%energy overhead over 8 h.We argue this is an acceptable trade-off for mission-critical deployments requiring guaranteed security.These findings demonstrate iSTSP’s potential as a reliable solution for secure WSN synchronization and motivate future work on large-scale IoT deployments and integration with energy-efficient communication protocols.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A pump operating as a turbine(PAT)is a type of hydraulic machine capable of functioning both as a pump and as a turbine by reversing the flow direction.The pump-as-turbine(PAT)approach presents an effective method of hydropower generation,particularly suitable for addressing the increasing global energy demands in rural and remote areas.In addition to its adaptability,PAT-based micro-hydropower systems typically incur lower operating costs than conventional hydrodynamic turbines,despite requiring higher initial investment.Recent research has focused on integrating PATs into pipe distribution systems to harness untapped hydraulic energy.This study presents the development and performance evaluation of a novel pump operating as a turbine(PAT)impeller,designed to enhance hydropower recovery in water distribution systems.A three-dimensional(3D)impeller model was created using Catia software,integrating airfoil(hydrofoil)geometries into the blade profile to improve the efficiency of power extraction during turbine operation.Unlike conventional designs,the new impeller configuration generates additional force components aligned with the rotor’s direction of rotation,thereby increasing the moment about the axis and enhancing angular velocity.Computational fluid dynamics(CFD)simulations performed in ANSYS Fluent confirmed that the redesigned PAT significantly improves both performance and efficiency,demonstrating superior power recovery compared to the original design.The results highlight the potential of integrating PAT systems with optimized blade geometries into water distribution networks,offering a viable solution for energy recovery and head reduction during periods of low demand.
基金the Puncak RM for the project under the grant 6733204-13069 to carry out the experiments。
文摘Graphene nanoplatelets(GNPs)have attracted tremendous interest due to their unique properties and bonding capabilities.This study focuses on the effect of GNP dispersion on the mechanical,thermal,and morphological behavior of GNP/epoxy nanocomposites.This study aims to understand how the dispersion of GNPs affects the properties of epoxy nanocomposite and to identify the best dispersion approach for improving mechanical performance.A solvent mixing technique that includes mechanical stirring and ultrasonication was used for producing the nanocomposites.Fourier transform infrared spectroscopy was used to investigate the interaction between GNPs and the epoxy matrix.The measurements of density and moisture content were used to confirm that GNPs were successfully incorporated into the nanocomposite.The findings showed that GNPs are successfully dispersed in the epoxy matrix by combining mechanical stirring and ultrasonication in a single step,producing well-dispersed nanocomposites with improved mechanical properties.Particularly,the nanocomposites at a low GNP loading of 0.1 wt%,demonstrate superior mechanical strength,as shown by increased tensile properties,including improved Young's modulus(1.86 GPa),strength(57.31 MPa),and elongation at break(4.98).The nanocomposite with 0.25 wt%GNP loading performs better,according to the viscoelastic analysis and flexural properties(113.18 MPa).Except for the nanocomposite with a 0.5 wt%GNP loading,which has a higher thermal breakdown temperature,the thermal characteristics do not significantly alter.The effective dispersion of GNPs in the epoxy matrix and low agglomeration is confirmed by the morphological characterization.The findings help with filler selection and identifying the best dispersion approach,which improves mechanical performance.The effective integration of GNPs and their interaction with the epoxy matrix provides the doorway for additional investigation and the development of sophisticated nanocomposites.In fields like aerospace,automotive,and electronics where higher mechanical performance and functionality are required,GNPs'improved mechanical properties and successful dispersion present exciting potential.
基金this project under Geran Putra Inisiatif(GPI)with reference of GP-GPI/2023/976210。
文摘Accurate time synchronization is fundamental to the correct and efficient operation of Wireless Sensor Networks(WSNs),especially in security-critical,time-sensitive applications.However,most existing protocols degrade substantially under malicious interference.We introduce iSTSP,an Intelligent and Secure Time Synchronization Protocol that implements a four-stage defense pipeline to ensure robust,precise synchronization even in hostile environments:(1)trust preprocessing that filters node participation using behavioral trust scoring;(2)anomaly isolation employing a lightweight autoencoder to detect and excise malicious nodes in real time;(3)reliability-weighted consensus that prioritizes high-trust nodes during time aggregation;and(4)convergence-optimized synchronization that dynamically adjusts parameters using theoretical stability bounds.We provide rigorous convergence analysis including a closed-form expression for convergence time,and validate the protocol through both simulations and realworld experiments on a controlled 16-node testbed.Under Sybil attacks with five malicious nodes within this testbed,iSTSP maintains synchronization error increases under 12%and achieves a rapid convergence.Compared to state-ofthe-art protocols like TPSN,SE-FTSP,and MMAR-CTS,iSTSP offers 60%faster detection,broader threat coverage,and more than 7 times lower synchronization error,with a modest 9.3%energy overhead over 8 h.We argue this is an acceptable trade-off for mission-critical deployments requiring guaranteed security.These findings demonstrate iSTSP’s potential as a reliable solution for secure WSN synchronization and motivate future work on large-scale IoT deployments and integration with energy-efficient communication protocols.
