TERMINAL VELOCITY EQUATION FOR A TWO-PHASE BUBBLE IN AN IMMISCIBLE LIQUID MEDIUM

An analytical expression for the instantaneous terminal velocity of a two-phase bubble evaporating or collapsing in a less viscous, immiscible liquid at large Reynolds numbers is derived. The predicted results are compared with the experimental data of Sideman and Taitel [1]. There is good agreement between experiment and theory     

Extraction of delta-lognormal parameters from handwriting strokes

In the context of the Kinematic Theory of Rapid Human Movement, handwriting strokes are considered to be primitives that reflect the intrinsic properties of the neuromuscular system of a writer as well as the basic control strategies that the writer uses to produce such strokes. The study of these strokes relies on the extraction of the different parameters that characterize a stroke velocity profile. In this paper, we present a new method for stroke parameter extraction. The algorithm is described and evaluated under various testing conditions.     

Experimental Study of Fine Sand Particle Settling in Turbulent Open Channel Flows over Rough Porous Beds

Results are presented from laboratory studies investigating the behavior of fine sand particles within turbulent open channel flow conditions flowing over rough, porous beds. A particle tracking technique was employed to record and analyze sand particle motion within the flow, while mean and fluctuating flow velocities were measured by an acoustic Doppler velocimeter probe. Measured particle settling rates show a strong influence from flow turbulence, being generally enhanced in the near-bed and intermediate flow regions and retarded in the outer flow region, compared to their fall velocity in still water conditions. Experiments also reveal the relative degree of settling enhancement to increase with decreasing particle size. Correlation between particle and small-scale fluid motions is demonstrated through a quadrant analysis technique, with higher-order events for the two phases found to be dominated by ejections and sweeps associated with the bursting process. Particle interactions with large-scale turbulent flow structures, revealed through flow visualization with a moving frame of reference, are found to result in particle accumulation in peripheral trajectories on the downflow side of local eddy structures. Analytical and theoretical considerations suggest that both these turbulence scales provide preferential transportation mechanisms that will account for the enhanced sand particle settling rates observed.     

高速公路电子限速牌的实用改进型设计

针对目前高速公路限速提示牌无法很好地对司机起到警示作用的现状,本文设计了一套基于MCS-51单片机,包含光电检测装置和显示装置的电子提示系统.它不仅能方便设置并显示该路段的限制速度,以完成普通电子限速牌的限速提示功能,同时能将测得的车速实时显示,并自动判断是否超速.其扩展功能还可以实现记录不同时段的车流量.另外它低廉的造价和经实验证明较高的精度大大提高了它的可用性.     

Application of K008 camera in diagnostics of shock and detonation waves

Results of tests of the K008 camera to determine its resistance to the action of factors that accompany gaseodynamic experiments, such as powerful electromagnetic, acoustic, and optical interference, and its application as a component of laser Doppler velocity meters of objects thrown by an explosion are presented. __________ Translated from Izmeritel’naya Tekhnika, No. 5, pp. 46–49, May, 2007.     

过滤风速对纤维过滤器压力损失的试验研究

从理论上分析了过滤风速对纤维压力损失的影响,用ORIGIN软件给出数学模拟曲线。介绍了试验设备及测试方法,通过试验得出过滤风速和压力损失变化关系。     

ZGM80G型中速辊式磨煤机出力不足的原因分析及解决方法

对包头二电厂ZGM80G型中速辊式磨煤机出力不足的原因进行分析,并提出了解决方法。     

A power series for vibration of a rotating nanobeam with considering thermal effect

In this article, the equation of motion for a rotating nanocantilever has been developed based on the Euler–Bernoulli beam model, which includes the effect of temperature, small scale effect, and centrifugal force. A power series method has been employed to obtain the exact solution of the natural frequencies. The results also compared with other solutions of exact and approximate differential quadrature method. The effects of temperature, angular velocity, and small scale in the vibration characteristics of a rotating nanocantilever beam are investigated. It is shown that the effect of temperature plays a significant role in the behavior of the vibration of a rotating nanocantilever. Nondimensional frequency increases in the first mode with increasing the nonlocal parameter while it is inverse for the second and third modes of vibration.     

高山滑雪速度的建模与求解

针对高山滑雪中运动员的体重、滑雪板的长度、滑雪板的腰宽以及滑雪道的不同对运动状态的影响,通过分析受力建立力学模型.基于微元的变化建立微积分模型,对模型进行求解验证.最终得到结论:在单一变量的情况下,体重大的具有优势,能够先到达坡底;滑雪板腰宽相同时,长度更长的滑雪板速度更快;在宣雪道上滑行时,全地域滑板比竞技板更快.通过数据验证表明,该模型的建立可以有效地为高山滑雪运动员提供了一种理论知识依据.     

Axial Dispersion Coefficient and Mass Transfer Rate in Pulsed Column

This work has investigated an improvement for the usual batch denitration by formic acid. It studied several destruction characteristics of nitric acid and formic acid in a continuous denitration process newly suggest in this work which consisted of a continuous denitration by formic acid and a residual acid-electrolytic destruction system. Also, the precipitation behaviors of a few metal ions such as Mo, Zr, Nd, and Fe during the denitration were investigated. The continuous denitration by formic acid reached a steady state in 30 min and showed a dependency of the final acidity on the residence time of the feeding solution in the reaction. In a Ti-IrO₂ electrolytic cell, the destructive rates of formic acid and nitric acid were 1.37×10^-2M-cm²/h-mA and 9.33×10^-3 Mcm²/hmA, respectively. The nitric acid was reduced at the Ti cathode and the formic acid was oxidized at the IrO₂ anode. The suggested denitration process combining a chemical system and an electrolytic system could treat continuously a feeding nitric acid of 2.0 M below about 0.1 M. The precipitation of the metal ions occurred almost totally in the denitration column.