PROPAGATION OF LOVE WAVES IN PRESTRESSED PIEZOELECTRIC LAYERED STRUCTURES LOADED WITH VISCOUS LIQUID

We investigate analytically the effect of initial stress in piezoelectric layered structures loaded with viscous liquid on the dispersive and attenuated characteristics of Love waves, which involves a thin piezoelectric layer bonded perfectly to an unbounded elastic substrate. The effects of initial stress in the piezoelectric layer and the viscous coefficient of the liquid on the phase velocity of Love waves are analyzed. Numerical results are presented and discussed. The analytical method and the results can be useful for the design of chemical and biosensing liquid sensors.

Improving the seismic performance of base-isolated liquid storage tanks with supplemental linear viscous dampers

Large tanks are extensively used for storing water,petrochemicals and fuels.Since they are often cited in earthquake-prone areas,the safe and continuous operation of these important structures must be ensured even when severe earthquakes occur,since their failure could have devastating financial and socio-environmental consequences.Base-isolation has been widely adopted for the efficient seismic protection of such critical facilities.However,base-isolated tanks can be located relatively close to active faults that generate strong excitations with special characteristics.Consequently,viscous dampers can be incorporated into the isolation system to reduce excessive displacement demands and to avoid overconservative isolator design.Nonetheless,only a few studies have focused on the investigation of seismic response of base-isolated liquid storage tanks in conjunction with supplemental viscous dampers.Therefore,the impact of the addition of supplemental linear viscous dampers on the seismic performance of tanks isolated by single friction pendulum devices is investigated herein.Four levels of supplemental damping are assessed and compared with respect to isolators′displacement capacity and accelerations that are transferred to the tanks.

Hydrodynamic Behavior of a Single Bubble Rising in Viscous Liquids

The rising behavior of single bubbles has been investigated in six systems with different viscosity and Morton number(Mo) from 3.21×10-11 to 163. Bubbles with maximum equivalent diameter of up to 16 mm were investigated. The bubble Reynolds number(Re) ranged from 0.02 to 1200 covering 3 regimes in which two func-tions are obtained relating the drag coefficient,CD,with Re and Mo. It has been found that in the high Reynolds number regime the drag coefficient increases until the Reynolds number of about 1200. The classic expression of Jamialahmadi(1994) is improved and extended to high viscosity liquids. A new relationship for the aspect ratio of deformed bubbles in terms of Re,the Etvs number and Mo,applicable to a wide range of system properties,espe-cially in high viscosity liquids,is also suggested.

Numerical simulation of viscous liquid sloshing by moving-particle semi-implicit method

网孔更少数字模拟法，动人粒子的半含蓄的方法(MPS ) 在这篇论文被介绍在海洋和海军的工程学习 sloshing 现象。作为一个网孔更少的方法，在传统的方法代替网孔的 MPS 使用粒子，管理方程是由粒子，和压力的泊松方程的关系的优点的 discretized 被不完全的 Cholesky 解决结合坡度方法( ICCG )，免费表面被数字密度的变化追踪。一个数字实验粘滞液体 sloshing 坦克被介绍并且与差别方法与 VOF，和另外的修正得到的结果相比走被增加使模拟更稳定。结果证明 MPS 方法对模拟合适粘滞与在容易安排粒子的优点，液体 sloshing 特别在弄弯的某建筑群上出现。

Experimental Study on Revolving Cross-flow Microfiltration of Highly Viscous Liquids

用转的 microfiltration ( MF )的试验性的调查跨流动的膜过滤器在经常的压力差别，和用 polyvinylidene 氟化物做的不同的扁平的膜的条件下面被执行( PVDF ， 0.1 m )，纤维素醋酸盐( CA ， 0.22 m )， sulfonated polyethersulfone ( SPES ， 0.22 m )并且聚酰胺( PA ， 0.45 m )分别地，在过滤实验被使用。跨流动的 MF 的 filtrate 团的依赖准时被测量联机。试验性的结果证明效果在高粘性媒介上跨流动在低粘性上是比那更重要的一个。

GLOBAL EXISTENCE OF CLASSICAL SOLUTION FOR A VISCOUS LIQUID-GAS TWO-PHASE MODEL WITH MASS-DEPENDENT VISCOSITY AND VACUUM

In this work, we obtain the global existence and uniqueness of classical solu-tions to a viscous liquid-gas two-phase model with mass-dependent viscosity and vacuum in one dimension, where the initial vacuum is allowed. We get the upper and lower bounds of gas and liquid masses n and m by the continuity methods which we use to study the compressible Navier-Stokes equations.

Axial power flow distributions of ultrasonic guided waves in viscous liquid-filled pipes

The axial power flow (APF) magnitude and attenuation distributions of ultrasonic longitudinal guided waves in viscous liquid-filled elastic pipes are investigated. The optimal location, optimal mode and its frequency-thickness product (fd) for the test of pipes filled with viscous liquid are chosen according to APF and attenuation distributions. The results show that the APF magnitude distribution is an important parameter in choosing the modes and parameters. A particular mode has weak dispersion in ranges of fd values with large group velocity, while other modes with smaller group velocity in the same fd ranges have stronger dispersion. It has been observed that, within these ranges, the chosen mode has a larger APF on the (pipe’s) wall. Therefore, in the region of fd values where a particular mode has a large group velocity, this mode will be effective to be used in testing elastic pipes filled with viscous liquid. The results obtained from both the APF analysis and attenuation distribution are consistent.

A Mass Transfer Model for Devolatilization of Highly Viscous Media in Rotating Packed Bed

A mass transfer model for devolatilization process of highly viscous media in rotating packed bed(RPB) was developed based on penetration theory and mass conservation.Before establishing the model,some mass transfer experiments of thin film were conducted in a designed diffusion cell including vacuum and feeding system. In this study,acetone was used as the volatile organic compound(VOC) and syrup as the highly viscous media.The thickness of thin film was changed by using different liquid distributor.It was found that bubbling played an important role in the devolatilization.The correlation of diffusion coefficient of acetone in highly viscous dilute solution was proposed.The relative error between predicted and experimental data was within the range of ± 30% for diffusion coefficient of acetone in syrup.A comparison of experimental data of RPB with model indicated that the relative error was within ± 30% for efficiency of acetone removal.

黏性牛顿流体液滴撞击干燥或预湿网面的实验研究

液滴撞击网面现象广泛存在于自然界和一系列应用中,液滴撞网后会穿透破碎产生二次液滴或不破碎全部附着在网面上,两种情况下都会残留液体在网面而形成预湿,影响后续撞击结果,但前人研究集中于低黏性液滴撞击干燥网面,黏性牛顿流体液滴撞击干燥或预湿网面的演化与机理仍有待探索.文章采用高速阴影成像技术,研究了黏性液滴(甘油水溶液)撞击干燥和预湿网面形成液指和破碎的演化规律,考虑了网面结构尺寸、液滴黏性及撞击前网面上预湿液膜厚度对撞击结果的影响.实验结果表明,液滴撞击干燥网面后形成液指的最大长度随网孔宽度降低、液滴黏性增加而减小;液滴黏性增加、网孔宽度减小均会抑制液滴对干燥网面的完全穿透;预湿液膜高度的增加抑制液滴对网面的完全穿透,并使不完全穿透时形成液指的最大长度减小.建立了考虑液滴黏性、网孔宽度和网面预湿的液滴撞击网面后不完全穿透时形成液指的最大长度预测模型,以及出现完全穿透时的临界参数理论预测模型,模型预测结果均与实验结果吻合良好.

转动杆上黏性流体承载量的探究

转动一根裹有黏性流体(如蜂蜜)的杆,杆上可以保留部分液体不滴落.针对此现象,之前理论研究大多基于N-S方程求解,无法直观解释现象发生的物理机理.本文在理论上创新性地采用类似量纲分析的方法,通过受力分析,避免了复杂冗长的流体力学方程求解,得到了由重力、黏性力、离心力、表面张力共同作用、交互主导的简洁理论模型;实验上,通过搭建稳定装置及合理控制变量,得到自洽的实验数据.理论分析与实验结果吻合度高,直观解释了转动杆上黏性流体不滴落的物理本质与关键因素.

黏性液膜在水平旋转柱体外的稳态行为

绕水平轴旋转的圆柱杆外表面上黏性液体会随着杆的旋转趋于稳态.本文研究了这一稳态对应的最大液体质量及其在不同条件下丰富的几何形状.在将液体流动近似视为斯托克斯流的前提下,杆上液体的单位最大载荷量W关于液体参数(密度ρ、黏度μ)及杆参数(转速Ω、半径a)的依赖关系为W∝√ρμΩa^(3).本文设计的控制变量实验表明,这一关系在较小雷诺数情况下(Re≤10)成立.在较高雷诺数(Re>10)区域,黏性液体的惯性效应是导致理论预测与实验结果出现偏差的主要原因.本文进一步探究了液膜横截面形状随杆转速变化的现象,实验观察到了椭圆、叶状、单勾和多勾形状的液膜,并定性解释了其形成原因.此外,实验中还发现了圆柱体轴向上形成液环的现象,液环数量与杆转速、杆半径成正相关.

带有液体粘滞阻尼器的超高层建筑抗风设计及风振响应分析

超高层建筑遮挡物较少,在风荷载作用下,结构顶部强烈的风振加速度会引起人的不适。通过在超高层结构合理布置液体粘滞阻尼器增加结构阻尼比,从而有效控制结构风振响应,达到减振目的。以珠海某超高层工程实例为背景,采用风洞试验计算脉动风荷载时程,在最不利风向角风荷载时程作用下,对比分析了阻尼器不同楼层布置位置、不同平面布置位置、不同阻尼弹簧刚度及不同阻尼参数下的减振效果,选出最合理阻尼器布置方式,结构顶层风振加速度得到有效控制,减振效果明显。

恒裕金融中心项目的风振控制计算分析及现场实测

以深圳恒裕金融中心B塔项目为例,通过对比结构顶点加速度、顶点位移、层间位移角、倾覆力矩的变化及附加阻尼比,验证了液体黏滞阻尼器在超高层建筑抗风中的明显减振效果。本文对目前建筑结构动力参数实测的方法以及测试设备进行了解释,同时,也介绍了对恒裕中心在设置阻尼器前后的结构基频、阻尼比、风振舒适度的现场测试情况。通过测试,验证了设置阻尼器可以有效降低结构在风振下的振动,提高结构的舒适度水平。测试结果受到外部因素影响其准确性虽然不足,但阻尼比和顶层加速度降低的趋势是确定的。这次测试也是世界上首次对设置了液体粘滞阻尼器结构进行的实体建筑的动力参数测试。

Electro-spray of high viscous liquids for producing mono-sized spherical alginate beads

Alginate beads, often used for controlled release of enzymes and drugs, are usually produced by spraying sodium alginate liquid into a gelling agent using mechanical vibration nozzle or air jet. In this work an alternative method of electro-spray was employed to form droplets with desired size from a highly viscous sodium alginate solution using constant DC voltage. The droplets were then cured in a calcium chloride solution. The main objective was to produce mono-sized beads from such a highly viscous and non-Newtonian liquid (1000–5000 mPa s). The effects of nozzle diameter, flow rate and concentration of liquid on the size of the beads were investigated. Among the parameters studied, voltage had a pronounced effect on the size of beads as compared to flow rate, nozzle diameter and concentration of alginate liquid. The size of beads was reduced to a minimum value with increasing the voltage in the range of 0–10 kV. At the early stages of voltage increase (i.e. up to about 4 kV), the rate of size reduction was relatively low, while the dripping mode dominated. However, in the middle part of the range of applied voltage, where the rate of size reduction was high (i.e. about 4–7 kV), an unstable transition occurred between dripping and jetting. At the end part of the range (i.e. 7–10 kV) jet mode of spray was observed. Increasing the height of fall of the droplets was found to improve the sphericity of the beads, because of the increased time of flight for the droplets. This was especially identifiable at higher concentrations of the alginate liquid (i.e. 3 w/v%).

Existence and blow-up of the solutions to the viscous quantum magnetohydrodynamic nematic liquid crystal model

In this paper, we investigate the coupled viscous quantum magnetohydrodynamic equations and nematic liquid crystal equations which describe the motion of the nematic liquid crystals under the magnetic field and the quantum effects in the two-dimensional case. We prove the existence of the global finite energy weak solutions by use of a singular pressure close to vacuum. Then we obtain the local-in-time existence of the smooth solution. In the final, the blow-up of the smooth solutions is studied. The main techniques are Faedo-Galerkin method, compactness theory, Arzela-Ascoli theorem and construction of the functional differential inequality.

水平管外高黏流体降膜流动形态及液膜分布规律的数值模拟

降膜元件上的流体流动行为能够反映该降膜式脱挥器的主要性能。采用数值模拟方法探究在水平管结构的降膜元件上高黏流体降膜流动的微观机理,在实验验证模型可靠性的基础上,考察不同流量下3层水平管外的高黏流体降膜流动形态及液膜厚度、速度变化规律等。结果表明:高黏流体在水平管外的降膜流动形态主要受重力和黏性力的影响,柱状流不易发展成完全的帘状流;高黏流体在水平管上部受到壁面支持力影响,而在水平管下部受到黏性力影响,流体会堆积在周向角0°~30°和150°~180°这两个区间内,导致液膜厚度异常增大;进液的3股流体在发生碰撞后,中间股液膜速度提高较多,但液膜厚度增加较少;流量减小至10.8 kg/h时,水平管外高黏流体会发生液膜收缩且内部出现空腔的现象,不利于高黏流体成膜流动。该研究可为水平管降膜式脱挥器的开发及工况设置提供参考。

Science Letters:Determination of benzalkonium chloride in viscous ophthalmic drops of azithromycin by high-performance liquid chromatography

一个高效的液体层析(HPLC ) 系统在 azithromycin 为 benzalkonium 氯化物(BKC ) 的决心在颠倒的阶段模式被使用粘滞眼的落下。Venusil-XBP (L)-C18(150 公里× 4 .6 公里， 5 μ m ) 列在 50 ° C 被使用。活动阶段由甲醇钾磷酸盐的混合物组成了(16:5， v/v ) 。二个样品准备方法被比较。结果建议与一个抽取过程相比，一个 deproteinization 过程快得多、更方便。用为样品准备的 deproteinization 过程，刻度曲线在范围是线性的 5.0 ∼50 μ g /ml。在内天和变化的内部天的系数是不到 10% 。平均恢复分别地在 10.0， 30.0，和 50.0 μ g /ml 的集中作为 96.70% ， 98.52% ，和 97.96% 被决定。在精确的可变性没超过 5% 。在结论，用一个简单样品处理过程的这个 HPLC 方法对在 azithromycin 监视 BKC 内容显得合适粘滞眼的落下。

Coating particles using liquids and foams based on viscous formulations with industrial mixers: Batch operation

Particle or powder coating with viscous liquids has been essential in industry for surface modification purposes to induce and enhance specific functionalities.This paper evaluates the performance of using foams (of different bubble diameters) versus liquids as a means of coating powder beds based on viscous liquid formulations.Coating with viscous liquids present numerous industrial challenges and therefore preparing foam equivalents can render the liquid component weak enough (through pre shearing to form the foam),to allow it to break up and coat particles under the shear forces exerted in a mixing device.In this study,two shear mixers are used;the first type consists of paddles in different configurations attached to a single rotating shaft,whilst the second type is a commercial twin screw mixer (TSM).The quality of coating achieved on the bulk powder bed using liquids and foams (stained with a dye) is assessed by image analysis to determine the homogeneity of the color distribution.In addition,scanning electron microscopy provides a tool to further investigate the coating quality of individual particles from the bulk product.The results show that large bubble (centimeter size) foams are much more effective at distributing within the fluidized powder bed compared to the starting viscous liquid and small bubble foams (submillimeter size).Furthermore,there is a maximum ratio of foam to powder beyond which agglomeration occurs and is insufficient to fully coat the particles.Coating of individual particles is achieved in the case of the TSM,whereas SEM proves that the single shaft paddle mixer crushes the particles and subsequently granulates them together to form granules of a size comparable to the size of coated particles seen after coating with the TSM.

液体弹珠翻越固着液滴的动态特性及运动机理

对体积在10—40μL之间的液体弹珠翻越液滴的过程进行可视化实验,研究液体弹珠翻越水平面上的固着液滴的动态行为。实验结果表明:弹珠以一定初速度撞击固着液滴后会发生反弹、翻越、弹飞和破裂4种运动状态,小体积弹珠只会产生前3种状态,弹珠体积越大越趋向于破裂。不同运动状态主要受弹珠初速度、弹珠体积、韦伯数(We)、雷诺数(Re)和邦德数(Bo)控制,在弹珠体积为10μL时,能够翻越同体积液滴的临界韦伯数在14—20之间,当体积达到40μL时,临界韦伯数为45—120。弹珠撞击液滴后受挤压,两者都会持续振荡变形,体积越大,弹珠的变形系数极值越大且液滴的振荡周期越长。该研究可为液体弹珠在微反应器方面的应用提供参考。

采用粘滞阻尼器的高桥墩连续刚构桥减震控制研究

为研究液体粘滞阻尼器参数对不同强度地震作用下高墩刚构桥减震控制的影响,以某墩高65 m的刚构桥为案例,采用midas Civil 2020建立有限元模型,并进行非线性时程分析。研究结果表明:梁端位移、墩底内力总体上均随着阻尼系数C增加而增大,随着阻尼指数α的增大而减小,综合考虑梁端位移、墩底内力及液体粘滞阻尼器的加工制造难度等因素,一般地震作用下,建议桥的液体粘滞阻尼器参数C取6000 kN(m/s)^(-α),α取0.4;强震时,C取7000 kN(m/s)^(-α),α取0.4。同参数阻尼器在不同强度地震作用下减震效果存在差异,强震作用下,顺桥向梁端位移、3#墩底弯矩、3#墩底剪力最大减震率为48%、23%、35%。在一般地震和强震作用下,各墩墩顶弯矩、剪力、位移的平均减震率分别为11.0%、15.9%、32.3%和46.1%、44.0%、45.1%。表明地震作用下,液体粘滞阻尼器适用于高墩刚构桥的减震设计。