Experimental validation of a numerical model for the transport of firebrands

The paper deals with the experimental validation of a numerical model for the transport and combustion of cylindrical and disk-shaped firebrands. The model solves the conservation equations of brand mass, kinetic and angular momentum, and volume. Validation consists in predicting the mass and spatial distributions of glowing firebrands that were produced from the experimental generator developed by Manzello and coworkers [S.L. Manzello, J.R. Shields, T.G. Cleary, A. Maranghides, W.E. Mell, J.C. Yang, Y. Hayashi, D. Nii, T. Kurita, On the development and characterization of a firebrand generator, Fire Saf. J. 43 (2008) 258–268]. Ten thousand firebrands per run are released with initial conditions that are randomly generated according to probability distribution functions deduced from experimental mass and spatial distributions under no-wind conditions. Whatever the wind conditions considered, numerical results are found to be in good agreement with experimental data.     

The study of cylinder liner plateau honing process

A lot of slide-honed cylinder surface topographies were measured and analysed in two and three dimensions. The correlation and regression analyses of parameters included in ISO 13565-2 (Rk group) and in ISO 13565-3 (Rq group) standards as well as of their 3D extensions were carried out. The Rk group of parameters was also compared with the Rq family as regards stability.     

圆柱齿轮的装配误差对齿轮工作性能的影响分析

为了更加准确的研究齿轮在工作过程中的摩擦、磨损、振动、噪声、传动速度的稳定性等工作性能,需要对齿轮的工作条件进行分析.本文通过分析齿轮系统在制造、装配过程中始终存在误差的特点,对安装齿轮的齿轮箱中的相关零件及其装配关系进行了总结,建立了误差模型,通过坐标变换,推导出齿轮齿廓曲线实际工作时的切向和法向方程,获得了齿轮副工作过程中影响工作性能的压力角、基节、公法线、重合度等参数状况,明确了装配误差对齿轮传动的重要意义,为齿轮副的设计、制造、装配、检测提供了理论依据.     

柱状药包岩石中爆炸的数值模拟

利用ANSYS/LS-DYNA3D对柱状药包在半无限岩石介质中爆炸情况进行了数值模拟,对柱状药包的爆炸在岩石内产生的应力变化进行了分析。给出了岩石弹性区内一点的应力变化时程曲线;并借助球形装药的经验公式对柱状装药的情况进行了分析比较,结果表明,应力波的峰值基本一致。该时程曲线可以用于多孔爆破计算。     

ICF实验中的靶材料研究

利用热诱导相分离技术制备出密度约 1 mg/cm3的超低密度聚合物泡沫,研究了凝胶、冷冻及干燥条件对泡沫结构的影响;进行了聚苯乙烯的合成与改性工艺研究,并用 L-B膜技术和流延法制备出厚度<50 nm 的聚合物超薄薄膜;研究了聚苯乙烯泡沫的液体浸润性能和机械性能,并采用溶液的自由基聚合反应制备了聚丙烯酸酯泡沫;进行了铜、铁柱腔制备技术的调研工作。     

以圆柱斜齿轮代替蜗轮的探讨

对圆柱斜齿轮、蜗杆啮合与蜗轮、蜗杆的啮合作了比较，提出在传递载荷不大的情况下，用圆柱斜齿轮代替蜗轮在实际应用中的意义．     

柴油机燃烧研究的进展

由于柴油机动力性，经济性和排放方面的要求，人们对柴油机缸内燃烧过程的研究越来越深入，在很多方面取得了进展。本文回顾和讨论了有关方面的研究内容，探讨了进一步的研究方向。     

压力容器冷成型筒体的残余应力问题

根据两个圆筒纵向开裂的失效实例，结合压力容器规范和标准中的有关内容讨论了冷成型圆筒的残余应力及其危害性。计算结果表明，卷板内表面的拉伸应力达到σＲＦＩ＝（０．４８～０．４９６）σｓ。建议开发工作表面σＲＦＩ＜０的容器制造方法     

Evaluation of cooked rice texture using a novel sampling technique

In this study, an alternate sampling method to the kernel sampling method (KSM), cylinder sampling method (CSM), was designed to investigate rice texture with respect to different soaking and boiling time. Pearson correlation coefficients analysis showed significant positive correlation between CSM and sensory evaluation of TD (Texuan Dongbei rice). Additionally, the relative standard deviation (RSD) values for CSM samples were lower than those obtained by KSM (kernels sampling method) which indicates that the CSM is more precise and consistent. The hierarchical cluster analysis for the texture data obtained by CSM showed that the rice varieties could effectively differentiate into two groups clustered when compared to KSM. In conclusion, CSM sampling method could be used for rapidly, precisely, and inexpensively assess texture of cooked rice in a manner that realistic reflects several sensory attributes.     

镁合金筒形件正反向快速气压胀形实验研究

采用两种不同轮廓的反向预成形模具以1.5mm厚的AZ31轧制镁合金板材为坯料进行了筒形件的快速气压胀形实验,结果表明预成形模具型腔轮廓曲率半径过小(r=5)时,反向胀形时间可达到120s。当反向胀形变形量较大时,在较高的气压下成形预成形件内表面会产生一些垂直于板料轧制方向的拉裂痕。筒形件单向和正反向气压胀形实验结果表明,在400℃温度下胀形300s可以成形出高径比(高度/直径)为0.37的完好筒形件,筒形件壁厚介于0.44和1.40mm之间,最薄处位于底部拐角处。