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介绍一种新颖的管材———高密度聚乙烯(HDPE)双壁波纹管,通过与传统钢筋混凝土圆管的比较,对其经济性做出评价,得到的主要结论为:管径≤800mm时,若埋深<2.5m,大多数情况下(Φ600例外)混凝土管的铺设单价要比HDPE管低;若埋深>2.5m,则混凝土管的铺设单价增长加快,比HDPE管要高出5%~22%左右。管径>800mm时,任一埋深HDPE管的铺设单价都比混凝土管高得多,此时需综合考虑其它因素,决定是否用HDPE管代替传统管材。 相似文献
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随着国家环境保护要求的提高和对建设资源友好型社会的大力提倡,市政工程中各类塑料管道得到了广泛应用。该文就常用不同形式大口径塑料管道受力结构和适用环境进行比较,以期对管材比选有所帮助。 相似文献
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The degradation of crosslinked polyethylene (XLPE) cable insulation during service, such as thermo-oxidation and water treeing may lead to a premature electrical breakdown of the XLPE insulation cables. Therefore, it is necessary to optimize the period of replacement to evenly distribute the replacement cost by ascertaining the deterioration degree. Estimation of the aging degree is at present the most important task for diagnosis of the residual lifetime of the power cable insulation. This paper presents a study on the changes in the dielectric properties of the thermally aged XLPE cables in the frequency range from 0.07~10 MHz. Based on electrical and physicochemical characterization, some new "dactylograms" for the thermally aged XLPE cable insulation have been proposed. 相似文献
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随着造船技术的发展,对于一些高新船舶,尤其是LNG船,海水对压载管路提出了更高的要求,同时在管路的布置上也产生了更多的限制。针对LNG船压载水排舷外管路及涂塑要求进行了阐述和分析,优化船舶压载水处理装置的管路布置,形成一套高效、节约且满足趋势要求的压载水管路布置方法。 相似文献
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本文详细地分析了上海石化总厂塑料厂高压聚乙烯产品在管道运输与贮槽贮存过程中,由于粉粒摩擦产生静电放电进而引起闪燥事故的各种因素,测定了粉粒分布、各种静电参数以及在粉尘与乙烯气体混合情况下在空气中爆炸的下限等大量数据,最后认为塑料厂高压车间的三次贮槽闪爆事故系静电放电所引起。作者希望采用静电、粉尘和可燃气的自动监控,采取爆炸卸压和爆炸遏制的措施,以防止爆炸事故。 相似文献
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Various types of floating solar photovoltaic (FPV) devices have been previously proposed, designed and constructed with applications primarily limited to onshore water bodies or near-shore regions with benign environmental conditions. This paper proposes a novel FPV concept which can survive harsh environmental conditions with extreme wave heights above 10 m. This concept uses standardised lightweight semi-submersible floats made of circular materials as individual modules. The floating modules are soft connected with ropes to form an FPV array. We first present the conceptual design of the floats and the connection systems, including hydrostatic, hydrodynamic, and structural assessments of the floats. To verify the motion response performance, we carried out 1:60 scaled model tests for a 2 by 3 array under regular and irregular wave conditions. From the time series and response spectra, the motion characteristics of the array and the mooring responses are analysed in detail. The proposed concept exhibits excellent performances in terms of modular motions with limited wave overtopping and no contact is observed between adjacent modules under the extreme wave conditions. The findings of this study can serve as a valuable reference to developing reliable and cost-effective FPV technologies for offshore conditions. 相似文献