Physicochemical and tribological properties of microalgae oil as biolubricant for hydrogen-powered engine

Hydrogen fuel offers a cleaner fuel alternative to fossil fuel due to more efficient burning as well as reduces the environmental and health issues brought by fossil fuel usage. In engine application, regardless of either pure hydrogen or in combination with air or/and other biofuel, all the moving parts are exposed to friction and wear, and lubricant is used to minimize friction and wear for optimum operation. Thus, in this study, the use of microalgae oil as an alternative biolubricant is evaluated from the physicochemical and tribological aspects. It is found that modified microalgae oil (MMO) has demonstrated great anti-friction and anti-wear potential, particularly the 10% modified microalgae oil blend (MMO-10). The coefficient of friction is reduced (up to 10.1%) and significant reductions of wear loss and surface roughness are obtained in comparison to pure poly-alpha-olefin. Lubricant's heat dissipation is also enhanced with MMO addition, demonstrating great prospect for MMO for hydrogen-powered engine utilization.     

纳米CeO_2、Fe燃油添加剂对柴油机性能影响的研究

为研究纳米颗粒添加剂对柴油机性能的影响,选取纳米CeO_2、Fe颗粒,采用超声波搅拌的方式适量添加到柴油中,制作出添加量为50×10-6和100×10-6的流态纳米燃料,并在Z2135柴油机上进行不同工况下的台架试验。研究表明:在现有试验条件下,通过超声波搅拌的方式在柴油中直接添加纳米颗粒难以形成长时间稳定的流态纳米燃料;微量纳米CeO_2、Fe颗粒的添加对改善缸内燃烧的作用不明显;对油耗的影响未见明显的规律性,但都在75%工况下降低了燃油消耗率;纳米CeO_2颗粒的添加对改善NO_x、CO的排放有积极影响。     

A tribological study of a ternary complex of zinc with dioxyethylenated octylphenol phosphate in water

A novel aqueous antiwear additive, a ternary complex of zinc with dioxyethylenated octylphenol phosphate and triethanolamine (TXOZ + TEA), has been synthesised. Its tribological behaviour in water was evaluated using a four‐ball tester. The results indicate that the complex in water exhibits higher load‐carrying capacity than mineral oil plus ZDTP, and excellent antiwear behaviour. The elemental composition of its rubbed surface was investigated with Auger electron spectroscopy (AES), and the results of this analysis are presented in the paper. The action mechanism of the additive is also discussed.     

Experimental study on the effect of titanium hydride content on the detonation performance of emulsion explosives

In order to improve the explosion characteristics of emulsion explosives, titanium hydride was added to emulsion explosives to produce a new type of hydrogen storage emulsion explosives. Charges with different contents of titanium hydride were evaluated through underwater explosion experiments and detonation velocity tests. The tests on underwater explosion and detonation velocity reveal that compared to pure emulsion explosives, the detonation parameters of emulsion explosives containing titanium hydride showed a trend of first increasing and then decreasing. When the mass ratio of titanium hydride in the emulsion explosive is 1 % to 3 %, all detonation parameters have been improved to a certain extent. When the mass ratio of titanium hydride in the emulsion explosive is 3 % to 10 %, only part of the detonation parameters (specific impulse, specific shock energy, specific total energy and volume energy density) has been improved. The maximum increase of specific impulse, specific shock energy, specific total energy and volume energy density of emulsion explosive containing titanium hydride is 7.06 %, 8.95 %, 3.97 % and 8.22 %, respectively. Based on the analysis, it is evident that though powdered TiH₂ participates in the detonation reaction process of the emulsion explosive, the majority of TiH₂′s energy is released during the secondary reaction occurring after the detonation wave front. Therefore, the detonation performance of emulsion explosives can be effectively improved by adding a certain mass ratio of titanium hydride.     

增材制造材料缺陷表征及结构完整性评定方法研究综述

金属增材制造过程中不可避免地会产生气孔和未熔合缺陷。尽管采取参数优化和后热处理能够在一定程度上降低缺陷水平,但至今尚无有效方法予以完全消除。这些缺陷作为典型的应力集中源,会诱导疲劳裂纹形核,从而大幅降低材料的疲劳强度和寿命,被视为增材构件可靠性服役的“顽疾”。从静态缺陷表征、动态缺陷演化、缺陷分级、缺陷-疲劳强度设计方法以及缺陷-疲劳寿命评估技术等五个方面论述增材制造缺陷与疲劳行为的研究进展。重点介绍借助X射线成像技术开展缺陷特征及演化的三维、无损、可视化表征与定量统计方法;进一步地,论述基于同步辐射光源的原位力学和疲劳测试系统及表征方法及其在原位、无损、实时、动态追踪缺陷或者裂纹演化机制方面中的应用;增材缺陷具有全域分布、形态多样、尺寸跨度大等特征,总结六种缺陷等级判断方法;在缺陷容限和损伤容限框架内,建立基于材料表面/亚表面/内部缺陷特征的疲劳强度和寿命评价方法。最后,指出借助数据驱动的高通量试验平台和机器学习算法、多尺度多物理场数值模拟是实现增材制造材料工艺设计-缺陷表征-性能评价一体化研究的重要研究课题。     

AMPS/DMAM/FA/NVP耐高温降失水剂的合成及性能研究

以2-丙烯酰胺基-2-甲基丙磺酸（AMPS）、N,N-二甲基丙烯酰胺（DMAM）、富马酸（FA）和乙烯基吡咯烷酮（NVP）为原料,以过硫酸钠-亚硫酸钠为引发剂,进行了四元共聚物的合成研究。采用正交实验获得了反应温度为50℃、引发剂用量为0．12oA、pH值为7的共聚合成条件。通过红外光谱、核磁共振氢谱表征、热重分析、Zeta电位测试和扫描电镜观察,证明合成了AMPS／DMAM／FA／NVP四元共聚物,该共聚物的分解温度为320℃左右,在180℃下具有良好的降失水性能,能将水泥浆的失水量控制在60mL以下。     

国内外天然着色剂现状和发展趋势(上)

对目前国内外食品添加剂食用天然色素的分类以及它们的结构特性、功能性和应用技术进行了综述。通过分析它们的技术发展趋势,提出了今后食用天然色素发展要求和建议。     

钻井液降滤失剂KJC的合成

降滤失剂作为重要的钻井液处理剂,其耐温耐盐能力直接影响水基钻井液的性能。从聚合物结构和官能团出发,选用对苯乙烯磺酸钠(SSS)、丙烯酰胺(AM)、烯丙基聚乙二醇(APEG)进行共聚得到钻井液降滤失剂KJC。以失水量为评价指标,通过单因素实验得到最佳合成条件为:m(APEG)∶m(AM)∶m(SSS)=1∶2∶1,单体质量分数20%,反应温度60℃,引发剂质量分数0.7%,反应时间5h。通过红外分析表明,合成产物结构与设计结构相符。性能评价表明,所合成的聚合物具有较好的抗温能力和抗钙能力。     

中原油田原油有机氯监控技术探讨

从中原油田原油有机氯含量调查与分析入手,阐述了有机氯超标对炼油企业的影响,针对现有有机氯含量监测方法进行了分析对比,并对监测技术进行优化,形成了一套切实可行的原油有机氯监测技术方法,在中原油田原油有机氯监测工作中取得了良好的实际应用效果。     

液相色谱-串联质谱高通量检测酸乳中多种塑料添加剂的迁移量

文章建立了一种液相色谱-串联质谱(Liquid chromatography tandem mass spectrometry,LC-MS/MS)高通量检测酸乳中多种塑料添加剂迁移量的方法.以乙酸乙酯为提取溶剂,超声提取两次,每次10 min,离心分离取上清液,氮吹至近干后用甲醇复溶,过有机滤膜后进LC-MS/MS检测...