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明渠试验加糙方法研究 被引量:6
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作者 m.asim 王龙 +1 位作者 郑钧 王兴奎 《水利水电技术》 CSCD 北大核心 2008年第2期67-70,共4页
在明渠水流试验中,经常需要进行不同糙率的研究。本文提出了一种采用绳索加糙的试验方法,并进行了各种水流条件和加糙绳距的试验。试验结果表明,加糙绳距对阻力系数的影响明显,绳距和流量越小,影响程度越大,随流量和绳距的加大,其作用... 在明渠水流试验中,经常需要进行不同糙率的研究。本文提出了一种采用绳索加糙的试验方法,并进行了各种水流条件和加糙绳距的试验。试验结果表明,加糙绳距对阻力系数的影响明显,绳距和流量越小,影响程度越大,随流量和绳距的加大,其作用逐渐减弱。加糙绳索的当量粗糙高度与绳距有关,各种试验条件的阻力系数与Rη遵循式(7)的变化规律。采用绳索加糙调整床面阻力的方法操作简单,调整灵活,变化范围大,为明渠阻力的试验研究提供了一种简便易行的方法。 展开更多
关键词 明渠阻力 人工加糙 阻力系数
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浅水流动阻力特性的试验研究 被引量:2
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作者 m.asim 王龙 +1 位作者 李丹勋 王兴奎 《水科学进展》 EI CAS CSCD 北大核心 2008年第3期378-382,共5页
为研究浅水流动的阻力特性,专门设计了一个试验模型,其规模较大,测量设施齐全。通过多种流量和加糙条件的试验得出:加糙密度将直接影响水流的阻力,小流量时的阻力系数变化明显,随流量的加大,加糙的影响逐渐减弱;阻力系数随相对粗糙度的... 为研究浅水流动的阻力特性,专门设计了一个试验模型,其规模较大,测量设施齐全。通过多种流量和加糙条件的试验得出:加糙密度将直接影响水流的阻力,小流量时的阻力系数变化明显,随流量的加大,加糙的影响逐渐减弱;阻力系数随相对粗糙度的加大而增加,不受流量变化的影响;表面流速分布均匀,其平均值与断面平均流速相关性良好。 展开更多
关键词 浅水流动 阻力系数 相对粗糙度 表面流速 试验研究
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Effect of Fiber Loadings and Treatment on Dynamic Mechanical, Thermal and Flammability Properties of Pineapple Leaf Fiber and Kenaf Phenolic Composites 被引量:6
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作者 m.asim M.Jawaid +1 位作者 M.Nasir N.Saba 《Journal of Renewable Materials》 SCIE 2018年第4期383-393,共11页
This study deals with the analysis of dynamic mechanical,thermal and flammability properties of treated and untreated pineapple leaf fiber(PALF)and kenaf fiber(KF)phenolic composites.Results indicated that storage mod... This study deals with the analysis of dynamic mechanical,thermal and flammability properties of treated and untreated pineapple leaf fiber(PALF)and kenaf fiber(KF)phenolic composites.Results indicated that storage modulus was decreased for all composites with increases in temperature and pattern of slopes for all composites,having almost the same values of E′at glass transition temperature(Tg).The peak of the loss modulus of pure phenolic composites was shown to be much less.After the addition of kenaf/PALF,peaks were higher and shifted towards a high temperature.The Tan delta peak height was low for pure phenolic composites and maximum for 60%PALF phenolic composites.Cole-Cole analysis was carried out to understand the phase behavior of the composite samples.Thermogravimetric analysis(TGA)results indicated that pure phenolic composites have better thermal stability than PALF and kenaf phenolic composites.Vertical and horizontal UL-94 tests were conducted and showed pure phenolic resin is highly fire resistant.The overall results showed that treated KF composites enhanced the dynamic mechanical and thermal properties among all PALF/KF composites. 展开更多
关键词 Pineapple leaf FIBER KENAF FIBER PHENOLIC resin DYNAMIC MECHANICAL analysis thermogravimetric analysis FLAMMABILITY
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Effect of Hybridization on the Mechanical Properties of Pineapple Leaf Fiber/Kenaf Phenolic Hybrid Composites 被引量:4
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作者 m.asim M.Jawaid +2 位作者 K.Abdan M.R.Ishak O.Y.Alothman 《Journal of Renewable Materials》 SCIE 2018年第1期38-46,共9页
In this study,pineapple leaf fiber(PALF),kenaf fiber(KF)and PALF/KF/phenolic(PF)composites were fabricated and their mechanical properties were investigated.The mechanical properties(tensile,flexural and impact)of the... In this study,pineapple leaf fiber(PALF),kenaf fiber(KF)and PALF/KF/phenolic(PF)composites were fabricated and their mechanical properties were investigated.The mechanical properties(tensile,flexural and impact)of the PALF/KF/PF hybrid composites were investigated and compared with PALF/KF composites.The 3P7K exhibited enhanced tensile strength(46.96 MPa)and modulus(6.84 GPa),flexural strength(84.21 MPa)and modulus(5.81 GPa),and impact strength(5.39 kJ/m2)when compared with the PALF/PF and KF/PF composites.Scanning electron microscopy(SEM)was used to observe the fracture surfaces of the tensile testing samples.The microstructure of the 7P3K hybrid composite showed good interfacial bonding and the addition of KF improved the interfacial strength.It has been concluded that the 3P7K ratio allowed obtaining materials with better mechanical properties(tensile,flexural and impact strengths)than PALF/PF and KF/PF composites.The results obtained in this study will be used for further comparative study of untreated hybrid composites with treated hybrid composites. 展开更多
关键词 Pineapple leaf fiber kenaf fiber phenolic resin hybrid composites mechanical properties
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