EXPERIMENTAL STUDIES ON MAGNETORHEOLOGICAL MODEL SUSPENSIONS

2007 ◽  
Vol 21 (28n29) ◽  
pp. 4967-4973 ◽  
Author(s):  
ALEXANDRA-MARIA TRENDLER ◽  
HOLGER BÖSE
Keyword(s):  
Magnetic Field ◽  
Shear Stress ◽  
Experimental Studies ◽  
Iron Particle ◽  
Solid Content ◽  
Oil Viscosity ◽  
Base Oil ◽  
Sedimentation Behavior ◽  
Mr Fluids ◽  
The Magnetic Field

Magnetorheological model suspensions with different contents of iron particles have been investigated. The results show an increase of the shear stress by increasing the magnetic field and the solid content, which was mathematically modelled. The influence of the solid content is approximately exponential without magnetic field and linear in strong magnetic fields. The effect of the temperature and of the base oil viscosity on the shear stress is negligible in the field but decisive without field. The sedimentation behavior also strongly depends on the iron particle content, where MR fluids with a higher concentration settle with a lower intensity due to the higher sediment height. The response time of the magnetorheological model suspensions could not be clearly determined, but it is less than 10 milliseconds.

ORIENTATION DYNAMICS OF MAGNETORHEOLOGICAL FLUIDS SUBJECT TO ROTATING EXTERNAL FIELDS

2001 ◽  
Vol 15 (06n07) ◽  
pp. 758-766 ◽  
Author(s):  
SONIA MELLE ◽  
MIGUEL A. RUBIO ◽  
GERALD G. FULLER
Keyword(s):  
Magnetic Field ◽  
Light Scattering ◽  
Simple Model ◽  
Critical Frequency ◽  
Optical Methods ◽  
Phase Lag ◽  
Rotating Magnetic Fields ◽  
Mr Fluids ◽  
Small Angle Light Scattering ◽  
The Magnetic Field

The formation and orientation of field-induced structures in magnetorheological (MR) fluids subject to rotating magnetic fields have been studied using two optical methods: scattering dichroism and small angle light scattering (SALS). The SALS patterns show how these chain-like aggregates follow the magnetic field with the same frequency but with a retarded phase angle for all the frequencies measured. Using scattering dichroism two different behaviors for both, dichroism and phase lag, are found below or above a critical frequency. Experimental results have been reproduced by a simple model considering the torques balance on the chain-like aggregates.

scholarly journals Chiral Magneto-Electrochemistry

2018 ◽  
Vol 4 (3) ◽  
pp. 36 ◽  
Author(s):  
Anup Kumar ◽  
Prakash Mondal ◽  
Claudio Fontanesi
Keyword(s):  
Magnetic Field ◽  
Experimental Studies ◽  
Spin Accumulation ◽  
Chiral Molecules ◽  
Electrochemical System ◽  
Ferromagnetic Electrodes ◽  
Spin Polarized ◽  
The Magnetic Field ◽  
Research Domain

Magneto-electrochemistry (MEC) is a unique paradigm in science, where electrochemical experiments are carried out as a function of an applied magnetic field, creating a new horizon of potential scientific interest and technological applications. Over time, detailed understanding of this research domain was developed to identify and rationalize the possible effects exerted by a magnetic field on the various microscopic processes occurring in an electrochemical system. Notably, until a few years ago, the role of spin was not taken into account in the field of magneto-electrochemistry. Remarkably, recent experimental studies reveal that electron transmission through chiral molecules is spin selective and this effect has been referred to as the chiral-induced spin selectivity (CISS) effect. Spin-dependent electrochemistry originates from the implementation of the CISS effect in electrochemistry, where the magnetic field is used to obtain spin-polarized currents (using ferromagnetic electrodes) or, conversely, a magnetic field is obtained as the result of spin accumulation.

Studies of Magnetically Active Silicone Elastomers on a Vibrostend

2021 ◽  
Vol 1037 ◽  
pp. 141-147
Author(s):  
Andrey Minaev ◽  
Juri Korovkin ◽  
Hammat Valiev ◽  
G.V. Stepanov ◽  
Dmitry Yu. Borin
Keyword(s):  
Magnetic Field ◽  
Field Effect ◽  
Dynamic Properties ◽  
Experimental Studies ◽  
Magnetic Field Effect ◽  
Magnetorheological Elastomer ◽  
Silicone Elastomers ◽  
Damping Coefficients ◽  
Deformation Properties ◽  
The Magnetic Field

Experimental studies magnetorheological elastomer specimens dynamic properties under the magnetic fields action on the vibrostend are carried out. Amplitude-frequency characteristics have been obtained. The magnetic field effect on the silicone magnetoreactive elastomers deformation properties and damping coefficients experimentally is established.

scholarly journals Anaerobic Digestion Technology for Methane Production Using Deer Manure Under Different Experimental Conditions

Energies ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1819 ◽  
Author(s):  
Hanxi Wang ◽  
Jianling Xu ◽  
Lianxi Sheng ◽  
Xuejun Liu ◽  
Meihan Zong ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Anaerobic Digestion ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Methane Production ◽  
Poultry Manure ◽  
Solid Content ◽  
Production Factor ◽  
Experimental Conditions ◽  
The Magnetic Field

Anaerobic digestion (AD) is an important technology for the treatment of livestock and poultry manure. The optimal experimental conditions were studied, with deer manure as a fermentation material and mushroom residue as an inoculum. At the same time, methane production was increased by adding zeolite and changing the magnetic field conditions. The results showed that a 6% solid content was the best condition for producing methane. The optimal conditions for methane production were obtained by adding 35 g of mushroom residue to 80 g of deer manure at 35 °C. The addition of organic wastewater (OW) improved methane production. The result of improving the methane production factor showed that adding zeolite during the reaction process could increase the methane production rate. When the amount of zeolite was over 8% total solids (TSes), methane production could improve, but the rate decreased. Setting a different magnetic field strength in the AD environment showed that when the distance between the magnetic field and the reactor was 50 mm and the magnetic field strength was 10–50 mT, the methane production increment and the content of methane in the mixed gases increased.

Experimental Investigation into the Effect of a Magnetic Field on Magnetorheological Fluids under an Impact Load

2012 ◽  
Vol 721 ◽  
pp. 179-184
Author(s):  
Ahmad Isnikurniawan ◽  
Yoshitaka Moroka ◽  
Hiromichi Ohba ◽  
Tatsuo Sawada
Keyword(s):  
Magnetic Field ◽  
Experimental Investigation ◽  
Qualitative Analysis ◽  
Apparent Viscosity ◽  
Impact Load ◽  
Magnetorheological Fluids ◽  
Mr Fluids ◽  
Experimental Apparatus ◽  
The Impact ◽  
The Magnetic Field

The apparent viscosity of magnetorheological (MR) fluids changes in the presence of a magnetic field. The stronger the magnetic field applied, the more the apparent viscosity increases. An increase in the apparent viscosity increases the restriction on the flow of MR fluids. In this study, we perform a qualitative analysis to investigate the effect of a magnetic field on MR fluids under an impact load. An experimental apparatus that consists of a drop-test tower was developed to simulate the impact load, and an MR fluid in a U-pipe was subjected to the impact load via a piston rod. In the experiment, we measured the displacement and velocity of the piston rod. On the basis of the results, the influence of a given magnetic field on the behavior of MR fluids under an impact load is discussed.

Experimental Investigation of the Transient Behavior of MR Fluids

2011 ◽  
Author(s):  
Ju¨rgen Maas ◽  
Dirk Gu¨th
Keyword(s):  
Magnetic Field ◽  
Experimental Investigation ◽  
Response Time ◽  
Dynamic Properties ◽  
Transient Behavior ◽  
Current Control ◽  
Large Signal ◽  
Carrier Fluid ◽  
Mr Fluids ◽  
The Magnetic Field

The transient behavior of MRF actuators is an important property for certain applications that is mainly affected by three delays, occurring from the dynamic properties of the coil current, the magnetic field and the torque generation by the MRF. In order to investigate the transient behavior of the generated torque with respect to the magnetic field, which is mainly affected by the motion of the MR particles in the carrier fluid, the mentioned response time of the electrical and magnetic domains must be in an appropriated ratio in comparison to the MRF response time to obtain reliable results by experiments. Therefore a special disc-type test actuator with outstanding dynamics is designed that minimizes the delays by the use of an ultrafast current control and a magnetic core made of soft ferrite material for preventing the effects of eddy currents. For the experimental investigation of the transient behavior of MR fluids, the small signal as well as the large signal behavior is analyzed for different test signals and load conditions of the actuator. Various results of the investigated transient behavior are shown finally for two different MR fluids featuring response times of about 1 ms for the fluid itself and switching times of about 4 ms for the MRF actuator.

Comparison of Affecting Factors on the Shear Stress Output of Cylinder-Typed MRF Clutch

2015 ◽  
Vol 1094 ◽  
pp. 453-457
Author(s):  
Hai Feng Ji ◽  
Chun Fu Gao ◽  
Xin Sheng He ◽  
Guang Zhang
Keyword(s):  
Magnetic Field ◽  
Shear Stress ◽  
Affecting Factors ◽  
Bingham Model ◽  
Theoretical Derivation ◽  
Proportionality Constant ◽  
Magneto Rheological ◽  
The Relationship ◽  
The Magnetic Field ◽  
Main Influence

With the purpose of studying the main influence on the cylinder-typed magneto-rheological fluid (MRF) clutch, the relationship between the output of shear stress and its affecting factors is presented in this paper; through theoretical derivation from the Bingham Model and the cylinder-typed shear model, the stress born by the MRF in the clutch is analysed, and the affecting factors on the clutch is also simulated and verified through experiments. The study shows that as the magnetic field strengthens, the shear stress of the cylinder-typed MRF clutch grows linearly, with proportionality constant at 0.162; the increase of shear rate, relevant to the magnetic field strength, makes little difference to the torque output, with proportionality constant at 0.00026B. The results indicate that mechanical-electrical integration of clutch devices can be achieved through the control of magnetic field output of the electromagnet.

scholarly journals SHEAR STRESS MEASUREMENTS AT THE SEA BOTTOM BY MEANS OF FERROFLUIDS

2018 ◽  
pp. 88
Author(s):  
Antonino Viviano ◽  
Laura M. Stancanelli ◽  
Rosaria E. Musumeci ◽  
Enrico Foti
Keyword(s):  
Magnetic Field ◽  
Shear Stress ◽  
Measurement Technique ◽  
Fixed Bed ◽  
Optical Readout ◽  
Experimental Campaign ◽  
Sea Bottom ◽  
Sensor Configuration ◽  
Bed Roughness ◽  
The Magnetic Field

An innovative measurement technique is proposed for investigating shear stress at sandy bottoms. This technique is based on the adoption of a ferrofluidic sensor and of an optical readout strategy. An experimental campaign is carried out for evaluating its performance. Experiments differ for the ferrofluidic sensor configuration (difference in the magnetic field) and for the bottom configurations (fixed bed or sandy bed). Calibration of the ferrofluidic sensor for the range of the investigated hydraulic condition and of the controlling magnetic field is presented. The ferrofluidic technique is promising when applied at sandy bottoms, as neither adhesion processes between sand grains and ferrofluid or influence of impacts of grains on the measurement are observed. In particular, the preliminary measure performed indicated that the ferrofluidic sensor is capable of sensing the different bed roughness.

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