Influence of Vibrations on Gas Bubble Formation in Liquids

The formation and motion of gas bubbles, and more especially the size of the bubbles formed, are important factors in many chemical engineering processes. In the present paper we describe the influence of vibration on bubble size and establish that the energy transferred from the vibrating channel to the bubbles is well correlated to the speed of vibration. We present a new model for determining and controlling bubble size and report results of experiments showing a high degree of compatibility between experimental results and the mathematical model and confirming the suitability of the model for engineering design applications.     

机械制图与化工制图课程整合

阐述了武汉科技大学化学工程与技术学院对机械制图与化工制图课程进行整合的缘由,介绍了各部分内容的选取与整合。指出了教学过程中发现的问题,并给出了解决这些问题的对策。     

Electrical Detection of Vibrations of Electrospun PVDF Membranes

We prepared electroactive PVDF membranes, which were subjected to mechanical as well as dual electro–mechanical signals and their responses were detected by the evoked electrical pulses. The aim was to obtain primarily electric energy that could be used for light signalling, sensing of the membrane properties and membrane motion detection. The obtained data showed the unique as well as usable properties of PVDF membranes. From this point of view, the gain and analysis of the electrical responses to combined electro–mechanical loads of PVDF membranes have been important in terms of identifying the mechanism. The detected electrical response of the PVDF membrane to their electro–mechanical pulses also indicated the possibility of using this phenomenon. Among others, it suggests monitoring of membrane fouling and use for a self-cleaning mechanism.     

Effects of Focused Vibrations on Human Satellite Cells

Skeletal muscle consists of long plurinucleate and contractile structures, able to regenerate and repair tissue damage by their resident stem cells: satellite cells (SCs). Reduced skeletal muscle regeneration and progressive atrophy are typical features of sarcopenia, which has important health care implications for humans. Sarcopenia treatment is usually based on physical exercise and nutritional plans, possibly associated with rehabilitation programs, such as vibratory stimulation. Vibrations stimulate muscles and can increase postural stability, balance, and walking in aged and sarcopenic patients. However, the possible direct effect of vibration on SCs is still unclear. Here, we show the effects of focused vibrations administered at increasing time intervals on SCs, isolated from young and aged subjects and cultured in vitro. After stimulations, we found in both young and aged subjects a reduced percentage of apoptotic cells, increased cell size and percentage of aligned cells, mitotic events, and activated cells. We also found an increased number of cells only in young samples. Our results highlight for the first time the presence of direct effects of mechanical vibrations on human SCs. These effects seem to be age-dependent, consisting of a proliferative response of cells derived from young subjects vs. a differentiative response of cells from aged subjects.     

标准鞍座的参数化绘图在化工设备装配图中的应用

针对化工设备装配图的绘制现状,以鞍式支座等标准零部件的参数化绘图为例,应用AutoLISP语言编写其工程图的参数化绘制程序,并且详细阐述了其关键步骤和实现过程,实践表明,通过参数化设计大大提高了工程图的设计效率,保证了设计质量。     

用Excel辅助AutoCAD制图

通过借用Excel在AutoCAD中制表和绘制多点直线、曲线方法的论述,找到了一种用Excel来辅助AutoCAD绘图简便、快捷、高效的方法,为今后实际问题的进一步解决铺平了道路。     

Vibrations of crystallographic defects associated with a single chain in polyethylene

The vibrational behaviour of crystallographic defects associated with a single chain were investigated for a dispiration, disclination, and dislocation in polyethylene. An approximate longitudinal modulus for the defects was determined by using conformational calculations to estimate the energy changes associated with changes in the length of a defect. This modulus, combined with the mass per unit length of the defect, was used to estimate the lowest longitudinal frequency of the defect, which was found to be around 100 cm^?1 for all the defects considered. Normal mode vibrational calculations for oligomers containing defects showed that the predicted lowest longitudinal modes could be identified by examination of the displacements associated with modes occurring in the estimated frequency range. It was shown that the defects could be considered as localized oscillators embedded in the crystal and coupled to the vibrational modes of the crystal. The presence of defects provides special mechanisms for coupling light waves and lattice vibrations in the crystal which may affect the Raman spectrum.     

来自天堂的植物

品牌档案品牌名称:Yothaka国家:泰国创立时间:1989年创始人:Suwam特色:发掘特色植物材料,手工制作家具。Yothaka的品牌精神,不仅倡导环保、解决社会问题,也带给世界最美丽的生活态度,放松、快乐,如同来自天堂。     

LNG开架式海水汽化器管道振动及改造实践

LNG接收站项目中的一台开架式海水汽化器(ORV),在投产阶段,设备和进出口管线振动严重,导致无法安全投产,给接收站的供气可靠性提出了严峻的挑战;经过宏观机械结构分析、计算分析、结合现场测量振动频率和振幅,通过实践调整支架、部管、弯头等多处变截面和拐弯,分担或减小LNG进入时的压力脉动,减少试车时随时间而变化的复杂空间力系作用的运动影响,消除了进出口管道和设备的振动,使得问题得以解决。     

木本植物作为人工湿地植物的可行性试验

景观水体的一个主要问题是水体富营养化将导致水华的暴发,并导致水体透明度下降,溶解氧降低,水生植物和鱼类大量死亡。为了防止水华爆发,人工湿地技术常被应用于景观水体水质维护之中,但其存在运行操作费用不足而导致的传统湿地植物到了秋季无人收割,和植物吸收营养盐总量较小等问题。因此,该课题通过中试研究,进行某良种柳树(S.matsudana Koidz)和黄花鸢尾(Iris wilsonii)的对比试验,并结合前人的研究成果,得出的结论为:该柳树的茎叶部一年中可去除氮的总量为10.8 g/m2,去除磷的总量为1.89 g/m2,在去除总量上比传统湿地植物具有明显优势,并且收割下来的柳树可作为生物质能源或造纸原料,能部分弥补湿地的运行费用,是一种很有潜力的湿地植物。未来,从保障湿地的运行效果和解决运行费用的角度来讲,具有经济价值的木本植物是湿地研究的一个方向。     

管道的管段图设计

本文结合工程应用实例介绍了在管道设计中绘制管段图(轴测图)的方法和注意事项。在管道实行工厂或工场预制化的情况下，使材料统计较准确和保证工程进度的如期完成。     

管道轴测图的设计

介绍了管道轴测图的定义及作用,说明了管道轴测图应包括的内容,对管道轴测图的规划设计以及对填写内容的要求进行了分析阐述,特别是对石油化工金属管道施工及验收标准的选择给出了建议,便于管道施工质量以及压力管道的监管。     

单线图在工艺管道施工中的应用

国外石化工程工艺管道施工中都使用单线图，图纸简单明了，施工人员读图容易，还便于编制施工进度计划、进行材料和质量的管理与控制。笔者在国内施工时也采用单线图，效果良好。