A NUMERICAL SIMULATION OF SWIRLING FLOW PNEUMATIC CONVEYING IN A HORIZONTAL PIPELINE

ABSTRACT

A numerical simulation for swirling and axial flow pneumatic conveying in a horizontal pipe was carried out with a Eulerian approach for the gas phase and a stochastic Lagrangian approach for particle phase, where particle-particle and particle-wall collisions were taken into consideration. The k-? turbulence model is used to characterize the time and length scales of the gas-phase turbulence. Models are proposed for predicting the particle source and additional pressure loss. The numerical results are presented for polyethylene pellets of 3.1 mm diameter conveyed through a pipeline of 13 m in length with an inner diameter of 80 mm, solid mass flow rate was 0.084 kg/s, and gas velocity was varied from 10 m/s to 18 m/s. The particle flow patterns, the particle concentration and the particle velocity, and additional pressure loss were obtained. It is found that the particle velocity and concentration has almost same value along flow direction in swirling flow pneumatic conveying. The profile of particle concentration for swirling flow pneumatic conveying exhibits symmetric distribution towards the centerline and the higher particle concentration appears in neighbor of wall in the acceleration region. At downstream, the uniform profile of particle concentration is observed. The particle velocity profile, on the other hand, is uniform for both swirling and axial flow pneumatic conveying. A comparison of the calculations with the measured data shows a good agreement within an average error of less than 15 percent.     

热处理对Al-Ni-Co单准晶相的影响

利用急冷固法获得柱状Al<,70.1>Ni<,24>Co<,5.9>单准晶,并用X线衍射仪测定Al<,70.1>Ni<,24>Co<,5.9>准晶的衍射强度.结果表明,在Al<,70.1>Ni<,24>Co<,5.9>的准周期面内H方向和K方向都出现了强衍射峰和弱衍射峰.Al<,70.1>Ni<,24>Co<,5.9>准晶经过热处理后,准点阵常数随着热处理温度降低而增大,在600和700℃之间准点阵常数将不发生变化,说明了热处理温度对准晶相变的影响,确定了Al<,70.1>Ni<,24>Co<,5.9>准晶结构的稳定性.     

Construction of a low parameter and disturbance sensitivity system by a model-following method

Many conventional design techniques can be only applied to ideal controlled objects without parameter variations and disturbances. This paper proposes a new method by which these techniques can be applied to practical objects with parameter variations and disturbances. The principle is to construct a model-following system which makes the practical object output follow the model output and to convert the practical object to the ideal object which has extremely low parameter and disturbance sensitivity.     

Capsule-Packed Freezing of Cooked Rice and Glutinous Rice Cakes

Cooked rice and commercial glutinous rice cakes were frozen by a capsule-packed freezing method we developed, then stored. Characteristics of samples frozen by this new method were compared with those of samples frozen in deep freezers (–20°C and –50°C), or chilled in an ordinary (5°C) or Cold Fog refrigerator (0°C). Texturometer measurements, glucoamylase digestion, and X-ray diffraction analysis of specimens thawed to room temperature indicated that the samples prepared by our new method were superior to those frozen in conventional freezers or chilled in refrigerators. Simulation experiments in a program freezer showed that rapid freezing and adequate tempering were characteristic of our capsule-packed method.     

Solution to the inverse regulator problem for discrete-time systems

A complete solution is given for the inverse problem of LQ optimal regulators for the discrete-time multi-input case. The Kalman equation for discrete-time systems is derived to characterize the optimal regulators. It is then shown that this equation holds for some quadratic weighting if and only if the feedback satisfies a condition corresponding to the circle criterion for continuous-time systems. The optimality criterion given here consists of this condition and an additional condition to ensure detectability. An example is given to illustrate the results.     

不同的表面处理对针织碳纤维复合材料的影响分析(英文)

纤维复合材料已经研究了数十年了。他们有着比传统材料,如钢材,优秀的多的力学性能。然而,由于相对较低的产量,梭织、编织与其3D纤维结构的复合材料被认为较难大量生产。因此,近年来,针织物在复合材料界获得了较高的关注,它的高度可塑性使针织复合材料可以直接生产制造成各种复杂形状的复合材料如管状、圆锥型等,使得材料的浪费可以降到了最低。本文使用了有表面处理和没有表面处理的纬编平针碳纤维制成复合材料。对两种复合材料的经向和纬向分别做了拉伸试验。结果显示:有表面处理的材料具有更好的拉伸性能,尤其是在wale方向上,有表面处理的复合材料比没有表面处理的复合材料的拉伸强度提高75.68%。     

iopeNet及其目的

我们已经提出的新的开放式区域控制网络“iopeNet”是一个全新的概念，与现有的设备控制网络没有冲突。本资料就此加以阐释。     

EFFECT OF HIGH PRESSURE ON THE ACCUMULATION OF IMP AND ON THE STABILITY OF AMP DEAMINASE IN RABBIT SKELETAL MUSCLE

This study evaluated the effect of high pressure on rabbit skeletal muscle, specifically on the production of inosinic acid (IMP), one of “umami” components, and on the activity of adenosine triphosphate (AMP) deaminase, which plays a role in the conversion of AMP to IMP. By increasing the pressure (0.1 to 300 MPa), nucleotide analysis showed that IMP content in muscle increased instantly with a concomitant decrease in ATP content. The IMP content of muscle at 300 MPa was approximately 15% higher than with lower pressures (0.1–200 MPa) when stored for 1 week at 4C after pressurization. These results suggested that the metabolism of nucleotides in muscle was not significantly impaired by pressure treatment. At 300 MPa, AMP deaminase maintained approximately 70% of the activity at 0.1 MPa. In contrast, the activity of purified AMP deaminase was completely lost at 200 MPa, and irreversible conformational changes were observed by in situ fluorescence spectroscopy. These results indicated that purified AMP deaminase was irreversibly denatured under pressure as high as 300–400 MPa.     

Analysis of ATP and Its Breakdown Products in Beef by Reversed-Phase HPLC

Analytical conditions for the quantitative determination of adenosine 5′-triphosphate(ATP), adenosine 5′-diphosphate(ADP), inosine 5′-monophosphate(IMP), adenosine 5′-monophosphate(AMP), hypoxanthine(Hyp), xanthine(Xan), inosine(Ino) and adenosine(Ado) in meat extracts by reversed-phase high-performance liquid chromatography (HPLC) were examined. A commercial ODS column with a 5-μm particle diameter was used, and expeimental parameters affecting the separation were discussed. Peaks in chromatograms of meat extracts were identified by retention time, co-injection with standards, absorbance ratios and the enzymatic peak shift method. The procedure proposed was adaptable as an indication of freshness of meat.     

通信协议标准规格

开放式综合设备网络可以满足建筑物节能、引进设备控制网络、连接现有的各种电气设备网络协议、通过扩展因特网的方式构建广域建筑设备控制网络等要求。 本文将对目前正在研究的，可望满足上述要求的设备控制网络的标准规格进行简要介绍。