scholarly journals In-situ Capacitance Sensing for the Settlement of Magnetorheological Fluid: Simulation and Experiments

2021 ◽  
Vol 8 ◽  
Author(s):  
Honghui Zhang ◽  
Zhiyuan Zou ◽  
Na An ◽  
Ningsong Xiong ◽  
Xu Yang
Keyword(s):  
Mr Damper ◽  
Magnetorheological Fluid ◽  
Fluid Simulation ◽  
Mr Fluid ◽  
Key Indicator ◽  
Mr Fluids ◽  
The Status ◽  
Long Time ◽  
The Relationship

In light of the insurmountable sedimentation of magnetorheological (MR) fluid, it is of great significance to ensure the performability of an MR damper by introducing a sensing method for MR fluid settling, and a key indicator to identify the health status of the MR damper is critical. However, the settling monitoring system for MR fluid can nowadays only function in a laboratory with transparent and non-magnetic tubes, which is not qualified for the in-situ sensing in a steel-made cylinder. Under the analysis of an open plate capacitor (OPC) configuration, the relationship between the concentration of magnetorheological fluid and the capacitance is investigated by simulation and experiments, and based on OPC, an in-situ sensing method for the settlement monitoring of magnetorheological fluid is designed. Long-time settling monitoring is carried out with home-made MR fluids, and the test results show that the sensing method can effectively reflect the status of settled MR fluids, and has the potential to be utilized in the identification of MR fluid compression points, which provides the strategic signal for the probable active or operational re-dispersing of MR fluid.

scholarly journals Squeezing Force of the Magnetorheological Fluid Isolating Damper for Centrifugal Fan in Nuclear Power Plant

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Jin Huang ◽  
Ping Wang ◽  
Guochao Wang
Keyword(s):  
Nuclear Power ◽  
Theoretical Foundation ◽  
Fluid Dynamic ◽  
Flow Behavior ◽  
Magnetorheological Fluid ◽  
Centrifugal Fan ◽  
Parallel Channel ◽  
Mr Fluid ◽  
Mr Fluids ◽  
Control Devices

Magnetorheological (MR) disk-type isolating dampers are the semi-active control devices that use MR fluids to produce controllable squeezing force. In this paper, the analytical endeavor into the fluid dynamic modeling of an MR isolating damper is reported. The velocity and pressure distribution of an MR fluid operating in an axisymmetric squeeze model are analytically solved using a biviscosity constitutive model. Analytical solutions for the flow behavior of MR fluid flowing through the parallel channel are obtained. The equation for the squeezing force is derived to provide the theoretical foundation for the design of the isolating damper. The result shows that with the increase of the applied magnetic field strength, the squeezing force is increased.

Thermal and tribological performance of graphite flake based magnetorheological fluid under shear mode clutch

2021 ◽  
pp. 1-24
Author(s):  
Manish Kumar Thakur ◽  
Chiranjit Sarkar
Keyword(s):  
Research Work ◽  
Magnetorheological Fluid ◽  
Tribological Performance ◽  
Graphite Flake ◽  
Shear Mode ◽  
Torque Sensor ◽  
Test Rig ◽  
Mr Fluid ◽  
Mr Fluids ◽  
Torque Transmission

Abstract In this research work, graphite flake has been used as an additive in magnetorheological (MR) fluid to improve its thermal and tribological performance. MR fluids with varying amounts of graphite flakes (0.5, 1, 2, 3, 4, and 5 wt%) are prepared to show effective thermal and tribological performance. A test rig is developed with a DC motor, torque sensor, and MR clutch operated in a shear mode to test the torque transmission. Results show the lubrication effects of graphite flakes in MR fluid. Torque transmission is improved in on-state and off-state using graphite flakes based MR fluid as compared to conventional MR fluid. Heating of MR clutch is also reduced with the graphite flakes based MR fluid. Wear marks and damages are decreased significantly with the increased amount of graphite flakes as found in surface roughness tests. SEM and EDS are used to characterize the worn surfaces. This research provides information about the effectiveness of graphite flakes in the MR clutch to improve the device's performance.

Perméabilité in situ du béton de peau, établie à partir de la percolation d'un gaz en régime d'écoulement permanent

2002 ◽  
Vol 29 (3) ◽  
pp. 360-368 ◽  
Author(s):  
Daniel Perraton ◽  
Alan Carter ◽  
Michel Vaillancourt ◽  
Bruno Lavoie
Keyword(s):  
Superficial Layer ◽  
Mass Concrete ◽  
Construction Site ◽  
Intrinsic Permeability ◽  
Apparent Permeability ◽  
Long Time ◽  
Concrete Blocks ◽  
The Relationship ◽  
Established Technique

In an attempt to apply the concepts developed by Carman and Klinkenberg for the measurement of permeability of a porous media using a gas, a permeameter for the in-situ measurement of intrinsic permeability of skin concrete has been developed. The established technique allows concentration of gas percolation through a well-defined zone in the superficial layer of concrete. The instrument, the measurement method, and the calculation procedure are described in details in this paper. Several series of tests have been performed in laboratory on concrete blocks (300 × 300 × 400 mm) to simulate measurements on the construction site. Three types of concrete, with different porosity, have been tested. The measurement of permeability performed on the concrete blocks have been accomplished both on shaped surfaces, which are representative of skin concrete, and on sawed surfaces, which are representative of mass concrete. Results show that the relationship between the water/cement ratio and the permeability of skin concrete varies distinctively compared with that of mass concrete. The permeameter allows quantification of what has been for a long time qualified as a determining element in terms of the durability of concrete against the corrosion of reinforcement, that is, the distinct permeability of skin concrete from that of mass concrete.Key words: skin concrete, in-situ permeability, intrinsic permeability, apparent permeability, permeameter, Klinkenberg.[Journal translation]

Development of Large Capacity Semi-Active Seismic Damper Using Magneto-Rheological Fluid

2004 ◽  
Vol 126 (1) ◽  
pp. 105-109 ◽  
Author(s):  
Hiroshi Sodeyama ◽  
Kohei Suzuki ◽  
Katsuaki Sunakoda
Keyword(s):  
Magnetic Fields ◽  
Large Scale ◽  
Hysteresis Loops ◽  
Mr Damper ◽  
Damping Force ◽  
Engineering Structures ◽  
Mr Fluid ◽  
Large Capacity ◽  
Mr Fluids ◽  
Magneto Rheological

In recent years, there has been increasing research in several industrial fields for development of semi-active vibration control devices. In particular, devices using magneto-rheological (MR) fluid have been attracting great research interest because they can realize high performance as capacity-variable dampers. MR fluids are controllable fluids that respond to applied magnetic fields. Applied magnetic fields drastically change the viscosity of MR fluids from an oily state to a semi-solid state. This paper describes a study on a large capacity device using an MR fluid, i.e., an MR damper. This developed MR damper provides a maximum damping force of 300 kN. Various tests were carried out and the dynamic characteristics, force-displacement hysteresis loops and controllable forces were investigated. These tests verified that the MR damper provides a technology that enables effective semi-active control of large-scale structure systems, i.e., real buildings and civil engineering structures.

Vibration Suppression by Controlling an MR Damper

1999 ◽  
Vol 13 (14n16) ◽  
pp. 2221-2228 ◽  
Author(s):  
Doyoung Jeon ◽  
Chanho Park ◽  
Kiyang Park
Keyword(s):  
Mechanical Properties ◽  
Time Delay ◽  
Response Time ◽  
Vibration Control ◽  
Control Systems ◽  
Vibration Suppression ◽  
Mr Damper ◽  
Mr Fluid ◽  
Mr Fluids

For the semiactive vibration control, a variable damper and proper control systems are essential. In this research a controllable damper was designed using the MR fluids and its mechanical properties such as damping constant and response time were measured. Since the response time of the MR damper was much longer than nominal MR fluid response time, the time delay of the damper should be considered in the design of controllers. It is shown that the advanced on/off vibration control which includes the damper time delay performs more effectively than the conventional one.

Dynamic Response of Magnetorheological Fluid Damper for Automotive Suspension and the Influence by Long-Time Standing-Still

2011 ◽  
Vol 105-107 ◽  
pp. 1689-1692 ◽  
Author(s):  
Hong Hui Zhang ◽  
Hai Peng Xu ◽  
Chang Rong Liao ◽  
Zhao Xiang Deng
Keyword(s):  
Dynamic Response ◽  
Response Time ◽  
Time Use ◽  
Mr Damper ◽  
Magnetorheological Fluid ◽  
Magnetorheological Fluid Damper ◽  
Fluid Damper ◽  
Long Time ◽  
Automotive Suspension ◽  
Key Parameter

Dynamic response is a key parameter for the engineering applications of MR damper. However, the response time has many different definitions, and which leads to a confusion of the measurement. Commonly, the response of MR damper in the new-designed status is focused, the instance after long-time use or standing-still has not been proposed. In this paper, the influence on the response time by the long-time standing-still is investigated, which shows that the response is largely lengthened. Next step, the measurement will be optimized, and the response of MR damper after long-time use will be in consideration.

Profile Imaging of Silicon Surface Reconstructions

1985 ◽  
Vol 43 ◽  
pp. 262-263
Author(s):  
O.L. Krivanek ◽  
G.J. Wood
Keyword(s):  
Electron Microscopy ◽  
Surface Structure ◽  
Structure Determination ◽  
Silicon Surface ◽  
Good Resolution ◽  
Surface Reconstructions ◽  
Bulk Structure ◽  
Point To Point ◽  
The Relationship

Electron microscopy at 0.2nm point-to-point resolution, 10-10 torr specimei region vacuum and facilities for in-situ specimen cleaning presents intere; ing possibilities for surface structure determination. Three methods for examining the surfaces are available: reflection (REM), transmission (TEM) and profile imaging. Profile imaging is particularly useful because it giv good resolution perpendicular as well as parallel to the surface, and can therefore be used to determine the relationship between the surface and the bulk structure.

A combined ultrastructural and gene molecular research for the relationship between human uterine cervical carcinoma and human papillomavirus

1990 ◽  
Vol 48 (3) ◽  
pp. 204-205
Author(s):  
Kun Lee ◽  
Jingyi Si ◽  
Ricai Han ◽  
Wei Zhang ◽  
Bingbing Tan ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Human Papillomavirus ◽  
Intraepithelial Neoplasia ◽  
Hpv Infection ◽  
Dot Blot ◽  
Homologous Sequences ◽  
Normal Cervical Epithelium ◽  
The Relationship ◽  
Chronic Cervicitis

There are more supports for the view that human papillomavirus (HPV) infection might be an etiological factor in the development of cervical cancer when the association of persistent condylomata is considered. Biopsies from 318 cases with squamous cell carcinoma of uterine cervix, 48 with cervical and vulvar condylomata, 14 with cervical intraepithelial neoplasia (CIN), 34 with chronic cervicitis and 24 normal cervical epithelium were collected from 5 geographic regions of China with different cervical cancer mortalities. All specimens were prepared for Dot blot, Southern blot and in situ DNA-DNA hybridizations by using HPV-11, 16, 18 DNA labelled with 32P and 3H as probes to detect viral homologous sequences in samples. Among them, 32 cases with cervical cancer, 27 with condyloma and 10 normal cervical epitheliums were randomly chosen for comparative EM observation. The results showed that: 1), 192 out of 318 (60.4%) cases of cervical cancer were positive for HPV-16 DNA probe (Table I)

The Problem of Identifying and Modeling the Relationship between Monetary Factor and Inflation in the Russian Economy

2008 ◽  
pp. 61-76
Author(s):  
A. Porshakov ◽  
A. Ponomarenko
Keyword(s):  
Money Supply ◽  
Money Demand ◽  
Russian Economy ◽  
Long Run ◽  
Complex Approach ◽  
Wide Range ◽  
Long Time ◽  
The Relationship ◽  
Supply Side Factors

The role of monetary factor in generating inflationary processes in Russia has stimulated various debates in social and scientific circles for a relatively long time. The authors show that identification of the specificity of relationship between money and inflation requires a complex approach based on statistical modeling and involving a wide range of indicators relevant for the price changes in the economy. As a result a model of inflation for Russia implying the decomposition of inflation dynamics into demand-side and supply-side factors is suggested. The main conclusion drawn is that during the recent years the volume of inflationary pressures in the Russian economy has been determined by the deviation of money supply from money demand, rather than by money supply alone. At the same time, monetary factor has a long-run spread over time impact on inflation.

Contemporary Qur'anic Studies in Iran and its Relationship with Qur'anic Studies in the West

2012 ◽  
Vol 14 (1) ◽  
pp. 45-72
Author(s):  
Morteza Karimi-Nia
Keyword(s):  
Islamic Law ◽  
Human Sciences ◽  
The West ◽  
Communications Technologies ◽  
Religious Learning ◽  
The Status ◽  
Islamic Republic Of Iran ◽  
Almost All ◽  
The Impact ◽  
The Relationship

The status of tafsīr and Qur'anic studies in the Islamic Republic of Iran has changed significantly during recent decades. The essay provides an overview of the state of Qur'anic studies in Iran today, aiming to examine the extent of the impact of studies by Western scholars on Iranian academic circles during the last three decades and the relationship between them. As in most Islamic countries, the major bulk of academic activity in Iran in this field used to be undertaken by the traditional ʿulamāʾ; however, since the beginning of the twentieth century and the establishment of universities and other academic institutions in the Islamic world, there has been increasing diversity and development. After the Islamic Revolution, many gradual changes in the structure and approach of centres of religious learning and universities have occurred. Contemporary advancements in modern sciences and communications technologies have gradually brought the institutions engaged in the study of human sciences to confront the new context. As a result, the traditional Shīʿī centres of learning, which until 50 years ago devoted themselves exclusively to the study of Islamic law and jurisprudence, today pay attention to the teaching of foreign languages, Qur'anic sciences and exegesis, including Western studies about the Qur'an, to a certain extent, and recognise the importance of almost all of the human sciences of the West.

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