HYDRAULIC ACTIVE GUIDE ROLLER SYSTEM FOR HIGH-SPEED ELEVATOR BASED ON FUZZY CONTROLLER

Increase of elevator speed brings about amplified vibrations of high-speed elevator. In order to reduce the horizontal vibrations of high-speed elevator, a new type of hydraulic active guide roller system based on fuzzy logic controller is developed. First the working principle of the hydraulic guide system is introduced, then the dynamic model of the horizontal vibrations for elevator cage with active guide roller system and the mathematical model of the hydraulic system are given. A fuzzy logic controller for the hydraulic system is designed to control the hydraulic actuator. To improve the control performance, preview compensation for the controller is provided. Finally, simulation and experiments are executed to verify the hydraulic active guide roller system and the control strategy. Both the simulation and experimental results indicate that the hydraulic active guide roller system can reduce the horizontal vibrations of the elevator effectively and has better effects than the passive one, and the fuzzy logic controller with preview compensation can give superior control performance.

Dynamic characteristics of a working platform supported by an AMG

A coupled electromechanical dynamic model for a working platform supported by an active magneticguide(AMG)is set up according to the special stiffness and damping theory of maglev system and theunique vibration of the working platform for a machine tool.The dynamic characteristics of a workingplatform supported by an AMG are studied using different groups of control parameters.Results show thatthe dynamic characteristics of the platform system,such as critical vibration frequency,vibration modeand so on,can be improved by adjusting the control parameters.This research offers theoretical supportfor ultra-high-speed and ultra-precise machine working platform designs,including the structure of plat-forms,the design of electromagnets,and the establishment of the control parameters.

Sterols possess immunomodulatory property:Activity guided isolation and in vitro screening of phytoconstituents of Pongamia glabra and Ficus glomerata

Objective:To isolate the phytoconstituents from the methanolic extracts of the stem bark of Pongamia glabra and Ficus glomerata,characterize spectroscopically and screen for in vitro immunomodulatory activity on human neurophils.Methods:A flavonoid(PGF)and an alkaloidal compound(PGA)from the extract of P.glabra and a steroidal compound(FGS)and tannin fraction(FGT)from the extract of F.glomerata were isolated using column chromatography technique and were subjected for the spectroscopic(FT-IR,1HNMR and LC-MS)and TLC studies to identify the compounds.The isolated compounds were screened for in vitro immunomodulatory activity on human neutrophils using nitroblue tetrazolium(NBT)dye test,phagocytosis of Candida albicans and neutrophil locomotion and chemotaxis assay at the concentration range of 100,50,25,12.50 and 5.00μg/mL.Results:From the spectroscopic and TLC studies data,the isolated compounds were identified as glabrin(PGA),karanjin(PGF),β-sitosterol(FGS),and tannin fraction(FGT).The isolated compounds PGA,PGF,FGS,and FGT exhibited significant(P<0.05)in vitro immunomodulatory activity in all the parameters studied.Conclusion:The steroidal compound,i.e.FGS was found to be more immunopotent than all constituents alkaloid,flavonoid and tannins.Hence,these constituents could be attributed to the immunomodulatory property of the plants.

GUIDING STUDENTS TO READ ACTIVELY THROUGH INTENSIVE READING

This article reviews the background and problems in theteaching of intensive reading (IR) to the students with non-English majors and proposes some activities for improving theteaching and learning process of the IR classroom. It is expectedthat with some applicable and effective activities, the teachercan help students read actively and grow into effective andindependent readers.