Assessment of the cause of cracking of hydraulic hose clamps

The aim of this study was to determine the cause of failure of the shells of hydraulic hose crimped fittings. For the purpose of examination the damaged crimped shells, undamaged crimped shells and shells prior to crimping were used. Fractographic and metallographic analysis, including chemical microanalysis of inclusions, were performed to determine the cause of failure. For this investigation, optical and scanning electron microscopes and hardness measurement were used. Damaged crimped shells contained higher amount of inclusions compared to undamaged crimped shells and substantially differed in microstructure and hardness. Furthermore, different geometry of the cross section at outer edge containing more effective stress concentrators was observed on failed crimped shells. Based on microstructural observation in cross section, hardness measurements and analysis of inclusions, the conclusion is that cracking of the shells occurred mainly due to deviations in the manufacturing process, combined with lower quality of shell material. Modifications to the technology were suggested to prevent this kind of failure.     

中国传统工艺振兴语境下的工匠精神

目的针对目前国家大力保护非物质文化遗产、倡导传统工艺振兴的语境下,如何传承和发扬好工匠精神,以促进当前我国非遗的保护和传统手工艺的传承与发展。方法以文献考据的方式,详细论述我国历史上不同时期关于工匠和工匠精神的解读,从古代"工"或"匠"到现代"大师"的演变,以及数千年来我国工艺文化传统所凝结成的大匠气度和大师境界,即将技艺臻于极致,将作品琢至完美的"工于技艺,匠心独运"的当代工匠精神。结论传承和发扬工匠精神须从政府加强指导、社会全力推崇、艺人珍视声誉等几方面形成合力,从而推动我国传统工艺行业的健康发展。     

等离子喷涂制备钢质涂布刮刀陶瓷涂层

以涂层平面度为评价标准,通过正交试验优化等离子喷涂工艺参数,在普通蓝钢刮刀上制备Al2O3-20%TiO2涂层,并对涂层的显微形貌、结合强度和耐磨性进行了研究.结果表明:弧电流550 A,喷涂距离100 mm,走枪速度0.8 m/s时等离子喷涂制备的Al2O3-20%TiO2涂层平面度最优;涂层具有良好的结合强度和耐磨性,结合强度大于30 MPa;磨粒磨损机理为切削和脆性断裂或脱落磨损.     

一起空分设备主换热器过冷故障的分析

在KDON-6000/3500型空分设备调试过程中,由于经验不足、操作不当,造成主换热器发生过冷故障。停运一台膨胀机,采用液氧返充操作使空分设备恢复正常工况。介绍故障发生经过和原因分析过程,以及防止同类故障再次发生的预防措施。     

过冷器污氮通道堵塞的排除

由于过冷器污氮通道被珠光砂堵塞,12000 m3/h空分设备的氧气产量不能达到设计值,由于后续生产系统需要无法停车检修,只能采取临时措施保持氧气产量的正常供应,最终通过扒砂并更换过冷器使故障得到彻底排除。介绍故障发生时空分设备技术参数的变化情况和原因分析过程。     

Prediction of the Viscosity of Liquid Mixtures

This paper describes the application of the theoretically based scheme of Vesovic and Wakeham, modified by making use of the hard-sphere model of Dymond and Assael, to the prediction of the viscosity of liquid mixtures. The purpose of the paper is to examine this scheme in more detail than earlier to find out in what circumstances it works well and when it fails. Hence, the scheme is employed to predict, for the first time, the viscosity of a wide range of mixtures of quite disparate liquids from groups of hydrocarbons, through combinations of alcohols and hydrocarbons, to halogenated refrigerants. It is shown that, in all cases, provided that the mass ratio of the pure components is close to unity, the predictions show excellent agreement with experiment.     

多点称重法测量质心误差修正

为了提高多点称重法测质心时的测量准确度,提出一种采用总体最小二乘法修正称重传感器受力点坐标的方法。首先,分析了多点称重法测量质心的原理,影响质心测量结果的主要误差源;其次,将标准件的形心坐标作为其质心的相对真值,并将该值用来修正称重传感器受力点的坐标;再次,改变标准件在质心测量设备上5个以上位置,采用激光跟踪仪测量标准件的形心坐标并转换到测量坐标系下,采用总体最小二乘法计算出称重传感器受力点的坐标;最后,测量标准件的质心进行验证。实验结果表明,修正后的设备质心测量误差≤0.1mm,可以通过修正称重传感器的受力点坐标,实现质心的高精度测量。     

Corresponding-States Modeling of the Speed of Sound of Long-Chain Hydrocarbons

Models based on the corresponding-states principle have been extensively used for several equilibrium and transport properties of different pure and mixed fluids. Some limitations, however, have been encountered with regard to its application to long chain or polar molecules. Following previous studies, where it was shown that the corresponding-states principle could be used to predict thermophysical properties such as vapor–liquid interfacial tension, vapor pressure, liquid density, viscosity, and thermal conductivity of long-chain alkanes, the application of the corresponding-states principle to the estimation of speeds of sound, with a special emphasis on the less studied heavier n-alkane members, is presented. Results are compared with more than four thousand experimental data points as a function of temperature and pressure for n-alkanes ranging from ethane up to n-hexatriacontane. Average deviations are less than 2%, demonstrating the reliability of the proposed model for the estimation of speeds of sound.Paper presented at the Seventeenth European Conference on Thermophysical Properties, September 5–8, 2005, Bratislava, Slovak Republic.     

石油元素的文化符号在文具产品设计中的应用

目的 从石油文化特色出发,提炼视觉符号用于文具产品设计中,赋予其人文情怀,传承石油文化,发扬石油精神,唤起消费者的兴趣。方法 以“石油元素”的视觉符号提取为切入点,从造型、色彩、材质3个视角,物质、造型、精神3个层面,深入剖析其形象符号,提炼其中典型的视觉要素,将其创造性地应用于文具用品设计中,并形成系列。设计中注重造型元素和风格的统一,同时也考虑到人体工学与需求、功能、材料、颜色、美感等的协调。结论 对设计要素的创新应用,是构建特色城市外在形象和内在文化的重要媒介,“石油元素”的提炼和再设计,是需要在深入研究石油文化内涵的基础上,融入恰当的设计思维和表现形式,为具有石油特色的城市的纪念品设计提供一些思路。     

PTMG-TMP混合扩链交联对聚氨酯树脂力学性能的影响

在常压、惰性气体保护下,利用二步法合成甲苯-2,4-二异氰酸酯（TDI）-聚丙二醇（PPG）预聚体,再用少量聚四氢呋喃醚二醇（PTMG）与三羟甲基丙烷（TMP）进行混合扩链交联,制备聚氨酯树脂（PU）固化产物并进行性能研究。采用FTIR对预聚体以及固化产物的分子结构进行表征,用万能试验机测试PU的力学性能。研究结果表明,少量PTMG的加入能降低反应的活性并改善PU固化产物的韧性。当TDI-PPG预聚体中-NCO的质量分数为24.0wt%、扩链交联剂中PTMG的含量为5wt%、异氰酸酯指数（R）介于1.01~1.05之间时,PU固化产物具有良好的力学性能,拉伸强度达到87.4 MPa,弯曲强度达到104~106 MPa,拉伸模量达到3.51~3.60 GPa,弯曲模量达到3.20~3.28 GPa,断裂伸长率达到4.45%~4.83%。     

团体标准分裂性的私有元治理机理研究

本文通过分析团体标准分裂性的原因,指出运用私有元治理协调团体标准的必要性,并分析了团体标准私有元治理的内涵、特征与运作方式,然后,通过对国家有机农业运动联盟的案例研究发现,私有元治理是解决团体标准分裂问题的有效方式,有助于推动团体标准发展,凝聚标准管制力量.     

蛙人水下声信号特征研究综述

蛙人由于体积小、噪声强度低,探测十分困难,并且蛙人可秘密潜入重点水域实施侦察或破坏,对水下区域安全提出了挑战。文章首先指出了水下蛙人的探测难点,然后介绍了反蛙人声呐装备的技术现状,对蛙人水下目标主被动声学信号特征的国内外研究情况进行了综述,提出了反蛙人声呐装备系统发展的关键技术,为我国反蛙人声呐系统的发展提供了参考。     

汽车橡胶密封条挤出口模结构分析及其实验验证

首先通过分析橡胶材料流变实验数据,确定采用Bird-Carreau本构模型;然后应用Polyflow软件对某实际EPDM橡胶密封条产品挤出过程中挤出口模流道结构对挤出的影响进行了有限元分析。结果表明,口模流道某些部位(如窄缝区域)进行适当的加宽有利于使挤出速度及熔体压力分布更均匀,挤出产品形状和实际形状更接近。     

Distribution of Products of Independent Variables

The inverse autocorrelations of a time series are defined to be the autocorrelations associated with the inverse of the spectral density of the series. They can be estimated by calculating the autocorrelations associated with the inverse of a spectral density estimate. Two diierent methods of estimating the inverse autocorrelations arise from two different methods of estimating the spectral density—autoregressive and periodogram smoothing. The estimates of the inverse autocorrelations are used to assist in identifying a parsimonious, moving-average, autoregressive model for the series and to provide rough initial estimates of the parameters for an iterative search for the maximum of the likelihood function. The techniques discussed are applied to chemical process concentration readings, wind velocity measurements, and moon seismic data.     

交互界面的形式解析

目的 自数字界面产生以来，依靠其独特优势逐渐成为主流的交互形式。排除技术发展的限定因素外，传统的物理界面仍在诸多领域发挥着不可替代的作用。而今设计领域对数字界面的认识出现过度依赖或为新而新的取宠态势。为回归理性，促成最佳的人机交互状态，有必要厘清两种界面的价值范围，为二者间的互惠共存、平衡发展提供理论依据。方法 在遵从以人为本的交互原则基础上，从建构前提、存在本质、优化呈现等角度分别采用不同的理论梳理两种界面的建构逻辑，从中明晰二者各自的优势，进而推导出不同情境下的选用原则。结论 在追求直觉性操控、塑造细腻感官体验、视觉失效的任务场景，强调操控精细度、强化人机信任度等条件下宜于选用物理界面;而在简化复杂任务、塑造超验性交互、实现信息可识化、追求体验个性化等条件下选用数字界面则更为合适。     

Comparison of the fatigue behaviour of two different forms of PMMA

This study investigates the fatigue behaviour of two forms of polymethylmethacrylate (PMMA): pure PMMA in the form of acrylic glass and PMMA-based bone cement. Acrylic glass demonstrated superior fatigue strength compared to hand-mixed porous bone cement but was significantly weaker than pore-free bone cement. The greater fatigue strength of bone cement in comparison to acrylic glass was attributed to its composite-like microstructure, containing pre-polymerized beads which are absent in the amorphous structure of acrylic glass. In tests conducted on notched specimens, the porous bone cement demonstrated superior fatigue strength to acrylic glass. The results could be predicted using the theory of critical distances, with errors no larger than 14%. This approach allowed us to show that, although porosity had a negative influence on the fatigue strength of the plain specimens in comparison to acrylic glass, the presence of porosity had no effect when the samples contained a notch or a hole. This finding is interesting when considering the effort put into removing porosity from bone cement during surgical operations, where it is used in situations where there are sharp stress concentrations in the form of protruding bone and the design features of artificial implants.     

A Review of Ethylene Permeability of Films

Ethylene plays a major role in regulating fruit ripening and fresh produce senescence during the postharvest period. Accumulated ethylene inside a fresh produce package has the potential to stimulate physiological activity and consequently accelerate deterioration, limiting storage life and leading to product losses. Current scientific effort focuses on the minimization of ethylene effects through ethylene removal or suppression of ethylene response. Other researchers are focussing on the development of sensors for measuring ethylene exposure within supply chain systems in order to be able to use this information to indicate produce quality and predict remaining shelf life. Full and optimal utilization of either ethylene removal or sensing technologies requires knowledge of the rates in which ethylene can flow to or from the package that the product is contained in. This study discusses the need for ethylene permeability data for polymer films and reviews the data available. Ethylene permeability of commercial films was found to range from 57 to 2.7 × 10^?16 mol.m/m².s.Pa at ambient temperatures, with activation energies being in the range of 37 000–48 000 J/mol. Amongst novel films, some containing zeolites could be 10 times more permeable, while permeability of wheat gluten films was highly influenced by relative humidity. However, generally, to date, it would seem that there is a scarcity of information on the transmission of ethylene through commonly used materials, especially at industrially relevant conditions of low temperature and high relative humidity, making prediction of ethylene conditions within a commercial package difficult. Collection of ethylene transmission data for the wide range of available films at industrially relevant conditions is required in order to maximize the utilization of newly developed ethylene removal or sensing technologies and subsequently contribute to the reduction in fresh produce losses within the supply chain. Copyright © 2015 John Wiley & Sons, Ltd.     

智能混凝土损伤自修复全过程分析

混凝土及其结构能够自动适应环境，在受到损伤后能够自行修复，是解决结构中的混凝土损伤的最佳途径。利用内置内含修复胶粘剂的胶囊实现了混凝土损伤的自修复，一旦混凝土中出现损伤或裂缝，胶囊破裂，其中的修复胶粘剂流出，使其修复。通过有限元软件ANSYS，建立了混凝土有限元模型，对其损伤自修复全过程进行了计算分析，揭示了损伤自修复的机理。最后，通过试验验证了计算分析方法的正确性和合理性。     

Effect of electrostatic charge of particles on hydrodynamics of gas-solid fluidized beds

The aim of this work was to investigate effect of electrostatic charge of particles on the fluidization hydrodynamics. Behavior of bubbles in beds of polyethylene particles was studied through analysis of pressure fluctuations in the frequency domain. Fluidized beds of uncharged, pre-charged and bed-charged particles were used in the experiments. Results revealed that in the bed of pre-charged particles, compared to uncharged experiments, particle-particle repulsive force increases the bed voidage and reduces equilibrium bubble size while the transition velocity to turbulent fluidization is decreased. In the case of bed-charged particles, at low gas velocities bubble fraction is greater compare to the other cases due to faster bubble coalescence in the presence of particle-wall attractive electrostatic force. Electrostatic charge of bulk increases by increasing the gas velocity. At high gas velocities, the repulsion force between highly charged particles overcomes the particle-wall effect on bubble formation and reduces the bubble size to less than in uncharged experiments. Accumulation of particles near the wall in the bed od bed-charged particles affects the hydrodynamics in two ways: first it accelerates bubble growth via bubble coalescence at low gas velocities, second it limits the bubble growth and reduces the transition velocity to turbulent regime to a value less than for pre-charged particles.