Structural Analogy for Dynamic Analysis of Liquid Sloshing

The analogy between the wave equation of liquid and the Navier equations of structural elasticity is examined in detail. By introducing appropriate parameters, the structural counterpart of the liquid sloshing model can be easily built. Therefore, the dynamic analysis of liquid sloshing can be reduced to that of structural elasticity, and the existing FEM structural analysis computer programs can be applied to liquid sloshing analysis without any modification. The present method also reveals the internal relationship between liquid sloshing and structural vibration. The effectiveness and reliability of the method is illustrated by the numerical example.

Pharmacokinetics of Remifentanil in Chinese Patients Undergoing Elective Surgery

Aim To study the pharmacokinetics of remifentanil in Chinese aduh patients undergoing elective surgery and compare the results with the data already published. Methods The pharmacokinetics of remifentanil was determined in 10 aduh patients undergoing elective surgery. Remifentanil 5 - 6 μg·kg^-1 was administered within 1 min after the induction of anesthesia. One point five millilitre of arterial blood samples were collected at 0 （baseline）, 1,2, 3, 5,7, 10, 15, 20, 25, 30, 45, 60, and 90 min after drug administration. Remifentanil concentration was assayed by HPLC/MS/MS. Resuits The concentration-time course of remifentanil was best described by a two-compartment model. Total clearance （CL = 2. 149 ± 0. 431 L·min^-1） of remifentanil was greater than the normal hepatic blood flow. The distribution half-life （t1/2α） [ 1.56 ± 0. 52 min （0.73 - 2.31 ） ] and the elimination half-life （t1/2β） [22.07 ± 10.30 min （9, 71 -36.07）] were similar with those in previous reports. Volume of distribution （ Vd = 65. 766 ± 29. 100 L） was about two times greater than that reported in previous studies of other ethnics. Conclusion In the present study, the volume of distribution is significantly greater than thai reported in previous studies of other ethnics, indicating that there are some differences in the pharmacokinetics of remifentanil among different ethnics.

纳米管温度计

本文讨论了Ga／in填充纳米碳管和纳米氧化物管温度计的研制、发现、发展及前詈，概述了纳米碳管温度计（测量范围为50℃～500℃）的特征、温度记录方法及In作为纳米温度计内工作物质的可能性。通过对填充Ga所具有的特殊凝固和熔化特征的回顾，阐述了Ga填充纳米碳管作为低温纳米温度计（0℃～69℃）及Ga填充纳米MgO管作为高温纳米温度计（高于700℃）的可行性。最后，讲述了采用测量Ga填充纳米碳管的电阻来标定温度的方法及如何解决纳米温度计在实际应用中存在的问题。

NUMERICAL PREDICTION OF AIRCRAFT HYDRAULIC SYSTEM BASED ON THERMAL DYNAMIC ANALYSIS

A mathematical model of principal elements of the aircraft hydraulic system is presented based on the heat transfer theory. The dynamic heat transfer process of the hydraulic oil and the pump shells within an aircraft hydraulic system are analyzed by the difference method. A kind of means for the prediction to variational trends of the aircraft hydraulic system temperature is provided during operation. The numerical prediction and simulation under the operational conditions are presented for ground trial running and the decelerated operation in flight. Computational results show that there is a good coincidence between the experimental data and the numerical predictions.

Analysis of drop deformation dynamics in turbulent flow

Drop breakage and coalescence influence the particle formation in liquid-liquid dispersions. In order to reduce the influencing factors of the whole dispersion process, single drops where coalescence processes can be neglected were analyzed in this work. Drops passing the turbulent vicinity of a single stirrer blade were investi- gated by high-speed imaging. In order to gain a statistically relevant amount of drops passing the area of interest and corresponding breakage events, at least 1600 droplets were considered for each parameter set of this work. A specially developed fully automatic image analysis based on Matlab was used for the evaluation of the resulting high amount of image data. This allowed the elimination of the time-consuming manual analysis and further- more, allowed the objective evaluation of the drops＇ behavior. Different deformation parameters were consid- ered in order to describe the drop deformation dynamics properly. Regarding the ratio of both main particle axes （0axes）, which was therefore approximated through an ellipse, allowed the determination of very small de- viations from the spherical shape. The perimeter of the particle （0peri） was used for the description of highly de- formed shapes. In this work the results of a higher viscosity paraffin oil （ηd =127 mPa. s） and a low viscosity solvent （petroleum, ηd = 1.7 mPa-s） are presented with and without the addition of SDS to the continuous water phase. All results show that the experimentally determined oscillation but also deformation times underlie a wide spreading. Drop deformations significantly increased not only with increasing droplet viscosity, but also with decreasing interfacial tension. Highly deformed particles of one droplet species were more likely to break than more or less spherical particles. As droplet fragmentation results from a variety of different macro-scale de- formed particles, it is not assumed that a critical deformation value must be reached for the fragmentation pro- cess to occur. Especially for highly deformed particles thin particle filaments are assumed to induce the breakage process and, therefore, be responsible for the separation of drops.

Kinetic studies on extra heavy crude oil upgrading using nanocatalysts by applying CFD techniques

Regarding the growth of global energy consumption and the paucity of light crude oil, extracting and using heavy and extra heavy crude oil has received much more attention, but the application of this kind of oil is complicated due to its very high molecular weight. High viscosity and low flowability complicate the transportation of heavy and extra heavy crude oil. Accordingly, it is essential to reduce the viscosity of heavy and extra heavy crude oil through in-situ operations or immediate actions after extraction to reduce costs. Numerical simulations are influential methods, because they reduce calculation time and costs. In this study, the cracking of extra heavy crude oil using computational fluid dynamics is simulated, and a unique kinetic model is proposed based on experimental procedures to predict the behavior of extra heavy crude oil cracking reaction. Moreover, the hydrodynamics and heat transfer of the system and influence of nanocatalysts and temperature on the upgrading of crude oil are studied. The geometry of a reactor is produced using commercial software, and some experiments are performed to examine the validity and accuracy of the numerical results. The findings reveal that there is a good agreement between the numerical and experimental results. Furthermore, to investigate the main factors affecting the process, sensitivity analysis is adopted. Results show that type of catalyst and concentration of catalyst are the parameters that influence the viscosity reduction of extra heavy crude oil the most. The findings further revealed that when using a 25 nm SiO_2 nanocatalyst, a maximum viscosity reduction of 98.67% is observed at 623 K. Also, a catalyst concentration of 2.28 wt% is best for upgrading extra heavy crude oil. The results obtained through sensitivity analysis, simulation model, and experiments represent effectual information for the design and development of high performance upgrading processes for energy applications.

Low-speed instability analysis for hydraulic motor based on nonlinear dynamics

A nonlinear dynamics model and a mathematical expression were set up to investigatethe mechanism and conditions of vibration creep acceleration.The model showsthat hydraulic spring and nonlinear friction are major factors that can affect low-speed instability.The mathematic model was established to obtain the change rule of speed andinstantaneous acceleration of the hydraulic motor.Then, Matlab was used to simulate theeffect of nonlinear friction force and hydraulic motor parameters such as coefficient of leakand compression ratio, etc., under low speed.Finally, some measures were proposed toimprove the low-speed stability of the hydraulic motor.

Thermogravimetric characteristics and different kinetic models for medical waste composition containing polyvinyl chloride-transfusion tube

Thermogravimetric study of medical transfusion tube （MTT） waste containing polyvinyl chloride （PVC） was carried out using the thermogravimetric analyser （TGA） with N2, at different heating rates of 5, 10, 20, 30, 50 ℃/min. The purpose is to obtain pyrolysis characteristics and kinetic parameters of medical waste. The experimental results indicate that the pyrolysis behavior of the MTT sample is in agreement with its main ingredient of PVC, appearing two stair stepping stages. The influence of the additives in MTT on pyrolysis behavior was also revealed, which could improve MTT pyrolysis at lower temperature in the first stage, and cause obvious unsmoothness and asymmetry of the second DTG peak. Four n-order kinetic models of Coats-Redfern, Ozawa, Kissinger and Freeman-carroll were used to get the kinetic parameters. Furthermore, a novel ＂two-step four-reaction model＂ was established to simulate the whole continuous process. The different methods and the kinetic parameters thus obtained were discussed and compared with each other in literatures. The reasons of deviation among kinetic values were tried to be elucidated. The new established model could more satisfactorily describe the pyrolysis process of MTT, being more mechanistic and conveniently serving for the engineering.

深海采矿扬矿硬管纵向振动的解析分析

深海采矿系统中，扬矿管纵向振动是影响扬矿管寿命的主要因素。本文对带有泵组及中间仓的阶梯式扬矿管的纵向振动进行了建模，并用解析方法对方程进行求解，通过计算机的模拟计算，分析了扬矿管纵向振动稳态响应的特性。

On The Analysis of Labyrinth Seal Flow Induced Vibration by Oscillating Fluid Mechanics Method

A numerical model and a solution method to analyze the labyrinth seal now induced vibration by Oscillating Fluid Mechanics Method (OFMM) are presented in this paper, including the basic equations and solution procedure to determine the oscillating velocity, pressure and the dynamic characteristic coefficients of Labyrinth seal such as the stiffness coefficients and damping coefficients. The results show that this method has the advantages of both less time cousuming and high accuracy. In addition,it can be applied to the field diagnosis of the vibration of the axis of turbomachinery system.

Characteristic analysis of hydraulic hybrid vehicle based on limit cycle

The theory of limit cycles was applied to hydraulic hybrid vehicle (HHV) to analyze the dynamic characteristics of the system. The exact mathematical models based on configuration diagram of HHV were built to study on equilibrium points, nonexistence of limit cycle and stability of equilibrium points. The analysis showed that if the Young's modulus of fluid is neglected, the equilibrium points of the system will be distributed on both sides of the initial function. In addition, there is a unique equilibrium point according to the practical signification of the system parameters. The nonexistence analysis showed that there is no limit cycle for the system, no matter how the viscosity coefficient B changes. The stability analysis of equilibrium points showed that the system is asymptotically stable about the equilibrium point at B≥0 and the equilibrium point is the center point of the system at B=0. Finally, the phase diagrams of global topological structure of HHV system were entirely described according to qualitative analysis of the singular points at infinity.