Analytical modeling of a diver dry suit enhanced with micro-encapsulated phase change materials     

M. L. Nuckols 《Ocean Engineering》1999,26(6):3377

Over the years, various forms of phase change materials (PCMs) have been utilized as thermal storage mediums for cooling and heating applications. Recently, the U.S. Navy has investigated using phase change materials inside divers' dry suits to enhance thermal protection in extremely cold water applications. The thermal performance of optional types of insulative Comfortemp¹ foam mediums, medium thicknesses, and foam-to-Thermosorb² ratios are evaluated analytically in this paper to compare the relative thermal performances of PCM-enhanced dry suits with existing commercial dry suits. An analytical model of dry suit systems, both conventional and those containing Comfortemp materials, is developed to predict their thermal performances in simulated ocean environments. This analytical model is used to compare the relative thermal performances of PCM-enhanced dry suits with existing commercial dry suits, and to assess the relative thermal performances of candidate Comfortemp foams, including those interspersed with different weight percentages of micro-encapsulated PCMs, in an effort to maximize thermal storage capabilities. The observations from this modeling effort provides guidelines and recommendations for materials selection and thickness requirements for candidate Comfortemp foams to be used in prototype dry suits for divers.  相似文献   

地电观测深井电缆的研制   总被引：2，自引：2，他引：0  

胡哲  蒋延林  张秀霞  赵卫红  杨恒勇  王福才  张骞 《中国地震》2017,33(2):338-344

井下地电观测是在地电观测中规避地表环境干扰的手段之一。针对井下地电观测装置长期稳定性的迫切需求,本文介绍了适用于井下地电观测中室外线路的内部结构、制作工艺、制作材料和可靠性检测结果等。本文所述型号的电缆能适用于开展井下数百米深度的地电观测,可保障井下地电观测装置的长期稳定性,是今后发展井下地电观测的关键技术。  相似文献   

真空绝热保温瓶温升规律试验研究          下载免费PDF全文

李忠  赵燕来 《探矿工程》2020,47(5):46-52

超高温钻孔轨迹测量仪是专为高温环境下的钻孔轨迹测量而开发的一种新型存储式测斜系统,以真空绝热保温瓶作为阻隔高温环境的主要手段,由于真空绝热保温瓶具有较大的长径比,其内部有效利用长度达到2.0 m左右,为了解在外界环境温度一定时,其内部沿轴向方向温升值的差异规律,为探管结构的合理布设提供依据,特别开展了本次试验研究。通过2只保温瓶的室内试验,获得了不同环境温度下的保温瓶内部温升值,通过对实测数据的分析,保温瓶内部温升规律主要有3个方面：一是温升值随时间基本为线性关系,温升速率随环境温度增加而加快;二是温升值与环境温度成3次曲线关系;三是保温瓶内部温升值由两端到中间逐步减小,中间部位温升值明显低于其两端。利用试验结果对探管结构进行了合理化的布设,采取了针对性的应对措施,确保了仪器工作温度指标达到项目考核要求,该试验结果也可为其他类似高温仪器的结构布设提供参考。  相似文献   

Assessment of the industrial utilization of scoria materials in central Harrat Rahat, Saudi Arabia     

M. R. Moufti  A. A. Sabtan  O. R. El-Mahdy  W. M. Shehata 《Engineering Geology》2000,57(3-4):155-162

Although basaltic volcanic scoria deposits are widespread in and around the scoria cones present in the Harrats, very few occurrences have been evaluated and still fewer have been exploited. The scoria from a quarry in central Harrat Rahat was investigated and assessed for its industrial utilization. Cubes were prepared from several concrete mixes using scoria as lightweight coarse and fine aggregates in different percentages. The compressive strength values of the cubes were found to be acceptable and satisfy the ASTM (1995) requirement for structural concrete. The scoria was also assessed for its utilization as a cement additive. Pozzolanic activity was tested according to the Italian standards and found to be acceptable. The strength activity index with Portland cement and the effectiveness of scoria admixture in controlling alkali-silica reactions were tested according to ASTM (1995) standards. Mortar cubes were specially prepared for these studies using different mixes and different storage procedures. The results satisfied the ASTM (1995) requirements as cement additive. The utilization of scoria as a heat-insulating material was tested and the results were found to satisfy the ASTM (1995) requirements. This fact suggests it could be utilized in the manufacture of the building blocks. It is recommended to evaluate the other scoria deposits, exploit the economically feasible ones and utilize them for different industrial applications. The manufacturing of heat-insulating concrete or building blocks using scoria is of prime importance as an energy saver.  相似文献   

An examination of insulation used on mine refrigeration chilled water pipes     

D. F. Howarth  A. D. S. Gillies 《Geotechnical and Geological Engineering》1987,5(1):83-91

  相似文献   

粉石英在微孔硅酸钙保温材料中的应用研究   总被引：3，自引：0，他引：3  

余志伟 《华东地质学院学报》1997,20(3):233-244

本文介绍了一种新的优质硅质原料－－粉石英，着重探讨了它的矿物组成、粒度分布、物化性质及其合成硅酸钙的试验。试验结果表明，粉石英与石在高温、高压和搅拌的条件下，可以合成硅硅钙石型优质微孔硅酸钙制品。为微孔硅酸钙行业开发了一种新的质优、价廉的硅质原料。  相似文献   

昆仑山多年冻土隧道施工温度影响分析   总被引：1，自引：0，他引：1  

张学富  苏新民  赖远明  喻文兵  吴亚平 《冰川冻土》2003,25(6):621-627

青藏铁路昆仑山隧道现场实测气温和地温资料表明，施工期间隧道衬砌现浇混凝土水化热、冬季施工采取的保温措施以及其它人为活动，造成了该隧道围岩的多年冻土融化较多．考虑水分迁移和冰水相变耦合影响，根据瞬态温度场问题的热量平衡控制微分方程和质量迁移方程，应用伽辽金法推导出了有限元计算公式，在ANSYS计算软件的工作平台上开发了计算软件，运用该计算软件对昆仑山隧道施工期间的融化进行了回冻预测分析，结果表明：保温材料对昆仑山隧道的回冻起着阻碍作用．在现场观测寒区隧道围岩的温度和应力时，必须考虑施工期间的融化圈的影响，而观测时间要长一些，否则，测量的温度和应力与隧道稳定后的温度和应力将有较大的差异。  相似文献   

高精度低频振动台及伺服隔振   总被引：8，自引：0，他引：8  

舒毓龙  孙耀东 《地震工程与工程振动》1998,18(4):131-136

本文提出了一种复合速度反馈技术,用以建造高精度大行程低频标准振动,同时,这种伺服隔振技术可大幅度降低地基振支对台面的干扰,降低地基造价。  相似文献   

热棒技术在国道214线共和-玉树高速公路宽幅冻土路基中应用的数值模拟研究     

徐安花 《冰川冻土》2014,36(4):987-993

高速公路路基幅面宽度的成倍增加,沥青路面的吸热效应更为显著,工程对其下伏多年冻土的热影响更为显著. 热棒、热棒保温板复合结构等传统工程措施能否保护宽幅高速公路下冻土稳定是一个亟待回答的问题. 根据带相变热传导有限元方法,对共和-玉树高速普通路基、热棒路基和热棒保温板复合结构路基在未来全球变暖情形下的地温场特征进行了数值模拟分析. 结果表明：在年平均气温为-3.5℃或地表年平均温度为-1℃的多年冻土地区,普通路基和热棒路基在全球变暖条件下路基下伏冻土都将发生融化,宽幅公路路基将会产生显著融沉变形,不能保证宽幅公路路基20 a使用期内的稳定性. 热棒保温板复式结构显示了较好的冷却路基效果,在第20年路基下多年冻土人为上限高于原天然上限,路基下富冰冻土仍处于冻结状态,可以保证宽幅沥青公路在服务期内的热稳定性.  相似文献   

季节冻土区高速铁路路基保温措施效果研究   总被引：4，自引：1，他引：3  

吕菲 《冰川冻土》2016,38(1):115-120

为减小季节性冻土区路基冻胀对高速铁路无砟轨道平顺度的影响,采用路基保温措施进行室内模型试验,对不同厚度保温板覆盖下路基AB组填料在多个冻融循环过程中的温度及变形规律进行了试验与分析.室内模型试验结果显示,XPS保温板具有良好的保温隔热作用,厚度越大,保温效果越好,保温措施有效控制了哈齐线路基AB组填料的冻胀变形,同时也降低了其残余变形.根据室内试验结果,采用20cm厚保温板的保温措施在哈齐线路基试验段进行现场试验.试验结果表明,该保温措施有效控制了左右线轨道板下方区域的冻胀变形,保证了轨面平顺度.  相似文献