Control performance comparison between tuned liquid damper and tuned liquid column damper using real-time hybrid simulation

Tuned liquid damper (TLD) and tuned liquid column damper (TLCD) are two types of passive control devices that are widely used in structural control. In this study, a real-time hybrid simulation (RTHS) technique is employed to investigate the diff erence in control performance between TLD and TLCD. A series of RTHSs is presented with the premise of the same liquid length, mass ratio, and structural parameters. Herein, TLD and TLCD are physically experimented, and controlled structures are numerically simulated. Then, parametric studies are performed to further evaluate the diff erent performance between TLD and TLCD. Experimental results demonstrate that TLD is more eff ective than TLCD under diff erent amplitude excitations.

Design, Optimization and Control of Extractive Distillation for Separation of Ethyl Acetate-Ethanol-Water Mixture Using Ionic Liquids

In this work, the process simulation of pressure-swing distillation(PSD) and extractive distillation(ED) using ionic liquid(IL) 1-butyl-3-methylimidazolium acetate([bmim][OAc]) as the entrainer for separation of ethyl acetateethanol-water mixture is performed. The design parameters of the two distillation processes are optimized with the minimum total annual cost(TAC) serving as the objective function. The results show that the TAC saving of ED process is 35.27% in comparison with that of PSD process in the case of achieving the same purity and yield of ethyl acetate.In addition, the dynamic controllability of ED process is further studied. The traditional two-point temperature control structure is proposed for the ED process, and it works pretty well while taking into account the disturbances in both feed rate and feed composition.

Optimum geometry of tuned liquid column-gas damper for control of offshore jacket platform vibrations under seismic excitation

In this study, the effectiveness of a tuned liquid column-gas damper, TLCGD, on the.suppression of seismic-induced vibrations of steel jacket platforms is evaluated. TLCGD is an interesting choice in the case of jacket platforms because it is possible to use the structural elements as the horizontal column of the TLCGD. The objective here is to find the optimum geometric parameters, namely orientation and configuration of vertical columns, length ratio, and area ratio of the TLCGD, considering nonlinear damping of the TLCGD and water-structure interaction between the jacket platform and sea water. The effects of different characteristics of ground motion such as PGA and frequency content on the optimum geometry are also investigated and it is observed that these features have some influence on the optimum area ratio. Finally it is observed that pulse arrangement of ground acceleration is one of the most important parameters affecting the efficiency of a TLCGD. In other words, it is found that the TLCGD＇s capability to reduce the RMS responses depends only on the frequency content of the ground acceleration, but its capability to reduce the maximum responses depends on both the frequency content and the pulse arrangement of the ground acceleration.

Wind-induced vibration control of bridges using liquid column damper

The potential application of tuned liquid column damper (TLCD) for suppressing wind-induced vibration of long span bridges is explored in this paper.By installing the TLCD in the bridge deck,a mathematical model for the bridge-TLCD system is established.The governing equations of the system are developed by considering all three displacement components of the deck in vertical,lateral,and torsional vibrations,in which the interactions between the bridge deck,the TLCD,the aeroelastic forces,and the aerodynamic forces are fully reflected.Both buffeting and flutter analyses are carried out.The buffeting analysis is performed through random vibration approach,and a critical flutter condition is identified from flutter analysis.A numerical example is presented to demonstrate the control effectiveness of the damper and it is shown that the TLCD can be an effective device for suppressing wind-induced vibration of long span bridges,either for reducing the buffeting response or increasing the critical flutter wind velocity of the bridge.

Torsionally Coupled Response Control of Offshore Platform Structures Using Circular Tuned Liquid Column Dampers

In this paper, the control performance is investigated of Circular Tuned Liquid Column Dampers (CTLCD) over torsional response of offshore platform structures excited by ground motions. Based on the equation of motion for the CTLCD-structure system, the optimal control parameters of CTLCD are given through some derivations on the supposition that the ground motion is a stochastic process. The influence of systematic parameters on the equivalent damping ratio of the structures is analyzed with purely torsional vibration and translational-torsional coupled vibration, respectively. The results show that the Circular Tuned Liquid Column Damper (CTLCD) is an effective torsional response control device.

Research on the principle of space high-precision temperature control system of liquid crystals based Stokes polarimeter

The magnetic field is one of the most important parameters in solar physics,and a polarimeter is the key device to measure the solar magnetic field.Liquid crystals based Stokes polarimeter is a novel technology,and will be applied for magnetic field measurement in the first space-based solar observatory satellite developed by China,Advanced Space-based Solar Observatory.However,the liquid crystals based Stokes polarimeter in space is not a mature technology.Therefore,it is of great scientific significance to study the control method and characteristics of the device.The retardation produced by a liquid crystal variable retarder is sensitive to the temperature,and the retardation changes 0.09°per 0.10℃.The error in polarization measurement caused by this change is 0.016,which affects the accuracy of magnetic field measurement.In order to ensure the stability of its performance,this paper proposes a high-precision temperature control system for liquid crystals based Stokes polarimeter in space.In order to optimize the structure design and temperature control system,the temperature field of liquid crystals based Stokes polarimeter is analyzed by the finite element method,and the influence of light on the temperature field of the liquid crystal variable retarder is analyzed theoretically.By analyzing the principle of highprecision temperature measurement in space,a high-precision temperature measurement circuit based on integrated operational amplifier,programmable amplifier and 12 bit A/D is designed,and a high-precision space temperature control system is developed by applying the integral separation PI temperature control algorithm and PWM driving heating films.The experimental results show that the effect of temperature control is accurate and stable,whenever the liquid crystals based Stokes polarimeter is either in the air or vacuum.The temperature stability is within±0.0150℃,which demonstrates greatly improved stability for the liquid crystals based Stokes polarimeter.

MHD Stability Analysis and Flow Controls of Liquid Metal Free Surface Film Flows as Fusion Reactor PFCs

Numerical and experimental investigation results on the magnetohydrodynamics（MHD） film flows along flat and curved bottom surfaces are summarized in this study. A simplified modeling has been developed to study the liquid metal MHD film state, which has been validated by the existing experimental results. Numerical results on how the inlet velocity（V）, the chute width（W） and the inlet film thickness（d0） affect the MHD film flow state are obtained. MHD stability analysis results are also provided in this study. The results show that strong magnetic fields make the stable V decrease several times compared to the case with no magnetic field,especially small radial magnetic fields（Bn） will have a significant impact on the MHD film flow state. Based on the above numerical and MHD stability analysis results flow control methods are proposed for flat and curved MHD film flows. For curved film flow we firstly proposed a new multi-layers MHD film flow system with a solid metal mesh to get the stable MHD film flows along the curved bottom surface. Experiments on flat and curved MHD film flows are also carried out and some firstly observed results are achieved.

Design and Realization of Liquid Stub Tuner Control System

In microwave circuit and aerial system, impedance matching is very important. Liquid stub tuner is a new type of impedance matching device. In the HT-7 Tokamak Ion Cyclotron Resonance Heating ( ICRH ) system, we have already adopted liquid stub tuner to replace the conventional stub tuner. It is urgent to develop a control system of the liquid stub tuner. This paper mainly introduces the design and realization of the liquid stub tuner control system , and briefly introduces its three controlling functions: local control, remote control and computer control.

WORKING LIQUID PRESSURE AND ITS CONTROL IN HYDRAULIC DRAWING PROCESSES OF CUPS

A method of setting up a pressure-stroke characteristic of the working liquid in hydraulic drawing is studied. A pressure-stroke characteristic and software for controlling its forming process are also developed. And a set of pressure controlling devices with PLC as a central processor are designed. It can be got from the relevant experiments that the pressure-stroke characteristic is correct and its control for forming process is available.

Doping Control Analysis of 16 Non-Steroidal Anti-Inflammatory Drugs in Equine Plasma Using Liquid Chromatography-Tandem Mass Spectrometry

Non-steroidal anti-inflammatory drugs (NSAIDs) are classified as Class 4 agents by the Association of Racing Commissioners International and are banned in racehorses during competition in Pennsylvania (PA). To control the abuse of these agents in racehorses competing in PA, a forensic method for screening and confirmation of the presence of these agents is needed. Equine plasma (0.5 mL) was acidified with 75 μL 1M H3PO4 to increase recovery of the analytes by liquid-liquid extraction using methyl tert-butyl ether (MTBE). Extracted analytes were separated by reversed-phase liquid chromatography using a C8 column under gradient condition. All 16 analytes were detected, quantified and confirmed using a triple quadrupole tandem mass spectrometry with selected reaction monitoring (SRM) in both negative and positive electrospray ionization modes. The limit of detection, quantification and confirmation of the analytes were 1.0 - 5.0 ng/mL, 1.0 - 5.0 ng/mL and 1.0 - 20 ng/mL, respectively. The linear dynamic range of quantification was 5.0 - 200 ng/mL. The method is routinely used in anti-doping analysis to control the abuse of NSAIDs in racehorses competing in PA.

Replacing liquid fyrite with digital to improve <i>in vitro</i>fertilization laboratory quality control procedures

In clinical in vitro fertilization (IVF), optimal culture conditions are required for production of high quality embryos and for achieving high pregnancy rates. Cell culture systems require vigilant attention to quality control and quality assurance, and upgrades to equipment and procedures require strenuous deliberation. During a 2-week maintenance period, we undertook an extensive analysis of incubator carbon dioxide (CO2) monitoring and the effect on culture media pH by comparing our traditional liquid Fyrite instruments to a certified and calibrated digital CO2 analyzer. The digital analyzer produced consistently lower CO2 readings and significantly greater precision than the liquid Fyrite. Media pH measurements showed significant variation depending on CO2 calibration device;however pH remained within manufacturers’ specifications. After superior performance by the digital analyzer, we incorporated this device into the incubator calibration and daily quality control procedures. A retrospective comparison of overall lab performance before and after this equipment switch demonstrated improved clinical pregnancy and implantation rates. This report illustrates the necessary caution when altering established laboratory procedures and equipment while highlighting the benefits of judiciously updating techniques and equipment in a laboratory setting that is often stubborn to change pre-existing, ingrained methodology.

Experimental analysis on adjusting performance of vapor-liquid two-phase flow controller

The vapor-liquid self-adjusting controller is an innovative automatic regulating valve.In order to ensure adjusted objects run safely and economically,the controller automatically adjusts the liquid flux to keep liquid level at a required level according to physical properties of vapor-liquid two-phase fluid.The adjusting mechanics,the controller’s performance and influencing factors of its stability have been analyzed in this paper.The theoretical analysis and successful applications have demonstrated this controller can keep the liquid level steady with good performance.The actual application in industry has shown that the controller can satisfactorily meet the requirement of industrial production and has wide application areas.

Application of Neural network PID Controller in Constant Temper-ature and Constant Liquid-level System

Guided by the principle of neural network, an intelligent PID controller based on neural network is devised and applied to control of constant temperature and constant liquidlevel system. The experiment results show that this controller has high accuracy and strong robustness and good characters.

Graco收购Liquid Control公司扩大胶粘剂业务

Graco公司于今年年初已经收购了LiquidControl公司的股份，其中包括其子公司Decker Industries，FL和在Wellingborough的Liquid ControlLimited。

HPLC Profiling for Quality Control of Secondary Metabolites of Aqueous and Hydroethanolic Extract of Gardenia aqualla Stapf &Hutch

WHO strategy on traditional medicine is based on security and quality of phytomedicine. Commonly adulterated affecting mostly metabolic and sexual dysfunction drugs. Control quality of those phytomedicines requires development of strategy and techniques applicable to them. Among the techniques, Reverse Phase Liquid Chromatography is the most used and has been developed in these studies to assess a protocol to characterize Gardenia aqualla leaves extract. The method consists in determining chromatographic conditions using organic and pH gradient models based on water and acetonitrile combined with pH modifiers made up of formic acid (AF) and ammonium hydroxide (NH3). Results show that extracts contain mainly acidic compounds quickly eluted by NH3 and more retained by AF. Optimal pH range for separation is 3 - 7 corresponding to 1.59 mM of NH3 and 6.55 mM of AF. In these conditions, elution of many polar compounds could be effective using a C18 based-deactivated column in a short period of time.

Nonlinear dynamic model and control of three-axis stabilized liquid-filled spacecraft attitude system

The fuel slosh in the storage tanks affects the attitude dynamics of the liquid-filled spacecraft during orbit transferring. To describe the interactions between the fuel slosh dynamics and the spacecraft attitude dynamics, a novel nonlinear dynamic model for three-axis liquid-filled spacecraft is presented, and in this paper, the multi-body dynamics method is utilized. In this model, the fuel slosh is represented by the motions of an equivalent sphere pendulum, and the fuel slosh is underactuated. The proposed dynamics model meets the demand of attitude controller design of liquid-filled spacecraft. Then, a nonlinear proportional-plus-derivative (PD) type controller is designed for the proposed model based on the Lyapunov direct approach. This controller can suppress the fuel slosh and stabilize the attitude of the liquid-filled spacecraft. Numerical simulations are presented to verify the effectiveness of the proposed nonlinear dynamic model and the designed underactuated controller when compared with the conventional control scheme.

Quality Control of Zhuang Medicine Xiaoyan Zhiyang Lotion

[Objectives]To establish the TLC identification methods of Llicis Rotundae Cortex and Mahoniae Caulis and the determination method of syringin content in Zhuang Medicine Xiaoyan Zhiyang Lotion.[Methods]Thin layer chromatography(TLC)was used to qualitatively identify Llicis Rotundae Cortex and Mahoniae Caulis in Zhuang Medicine Xiaoyan Zhiyang Lotion.The quantitative analysis of syringin in Zhuang Medicine Xiaoyan Zhiyang Lotion was carried out by high-performance liquid chromatography(HPLC).Chromatographic conditions are as follows:Luna 5μm C_(18)((2)100 A(250 mm×4.6 mm,5μm)column was adopted;acetonitrile(10%)-water(90%)was as the mobile phase,and the flow rate was 1.0 mL/min;the detection wavelength was 265 nm;the sample size was 5μL;the column temperature was 30℃.[Results]Syringin had a good linear relationship with its peak area in the range of 0.190-2.856μg(R^(2)=0.9995).The RSD values of precision,stability and repeatability experiments were all lower than 2.5%,and the average sampling recovery rate(n=6)was 100.37%(RSD=-0.88%).[Conclusions]The method had the advantages of simple operation,strong specificity,good repeatability and stability,and can be used for the quality control of Zhuang Medicine Xiaoyan Zhiyang Lotion.

Branch Quality Control of Gas-Liquid Two-Phase Flow Using a Novel T-Junction Type Distributor

In order to eliminate mal-distribution and ensure the side arm to produce desirable gas quality a special distributor is proposed. The experimental distributor mainly consists of a straight through section,a gas extraction line,a liquid extraction line and a side arm branch. A gas orifice and a liquid orifice are mounted at the gas and liquid extraction line respectively to control the outlet gas quality. The diameter of the liquid orifice was set to 2. 50 mm and three gas orifices with different size( dG= 2. 65,5. 00,10. 00 mm) were tested. The experiments were carried out at an air-water two-phase flow loop. The gas superficial velocity ranged from 6. 0 to 20. 0 m /s and the liquid superficial velocity was in the range of 0. 02- 0. 18 m /s. Flow patterns such as wave flow,slug flow and annular flow were observed. The gas quality of the side arm branch was found mainly determined by the flow area ratio of the gas orifice to the liquid orifice and independent of gas and liquid superficial velocity,flow patterns and extraction flux.

Systematic Evaluation and Meta-analysis of Efficacy and Safety of Zhichuanling Oral Liquid (止喘灵口服液) in the Treatment of Bronchial Asthma

Objective:To systematically evaluate the effectiveness and safety of Zhichuanling Oral Liquid(止喘灵口服液)in the treatment of bronchitis asthma.Methods:A systematic search of CNKI,Wanfang Data,VIP,CBM,Cochrane Library,PubMed,Embase and Web of Science was conducted to screen out randomized controlled trials of Zhichuanling Oral Liquid in the treatment of bronchial asthma.Meta-analysis and systematic evaluation of the included studies were conducted to finally included researches using the Cochrane Handbook 5.1 evaluation standard tool and RevMan 5.3 software.Results:Five studies were included,with a total sample size of 354 cases,176 in experimental group and 178 in control group.Meta-analysis showed that the total effective rate of Zhichuanling Oral Liquid combined with conventional treatment was better than that of conventional treatment alone(RR=1.27,95%CI[1.13-1.42],P<0.0001).Conclusion:Based on the existing data and methods,Zhichuanling Oral Liquid combined with conventional Western medicine in the treatment of bronchial asthma can improve the total effective rate.However,the quality of the included studies is not high and the number is small,so it is necessary to adopt clinical trial protocols with large samples,rigorous design and in line with international standards to improve the quality of evidence in the future.

液体火箭发动机健康监控技术研究进展

液体火箭发动机健康监控技术作为保障运载火箭安全、可靠发射的核心关键技术,经过几十年的发展,有力推动了航天事业的进步。介绍了液体火箭发动机健康监控技术中故障检测与诊断、容错控制与健康监控系统研制等技术的研究现状与发展趋势;梳理了健康监控领域面临的重难点问题,并提出相应的解决方案。分析展望了液体火箭发动机健康监控技术未来发展趋势,为从事火箭发动机健康监控技术研究的科研人员提供参考。