scholarly journals A Tactile Device Generating Repulsive Forces of Various Human Tissues Fabricated from Magnetic-Responsive Fluid in Porous Polyurethane

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1062
Author(s):  
Yu-Jin Park ◽  
Ji-Young Yoon ◽  
Byung-Hyuk Kang ◽  
Gi-Woo Kim ◽  
Seung-Bok Choi
Keyword(s):  
Magnetic Field ◽  
Polyurethane Foam ◽  
Experimental Tests ◽  
Adhesive Tape ◽  
Human Tissues ◽  
Relaxation Stress ◽  
Repulsive Forces ◽  
Particle Chains ◽  
The Magnetic Field ◽  
Psychophysical Test

In this study, a controllable tactile device capable of realizing repulsive forces from soft human tissues was proposed, and its effectiveness was verified through experimental tests. The device was fabricated using both porous polyurethane foam (PPF) and smart magnetorheological fluid (MRF). As a first step, the microstructural behavior of MRF particle chains that depended on the magnetic field was examined via scanning electron microscopy (SEM). The test samples were then fabricated after analyzing the magnetic field distribution, which was crucial for the formation of the particle chains under the squeeze mode operation. In the fabrication of the samples, MRF was immersed into the porous polyurethane foam and encapsulated by adhesive tape to avoid leakage. To verify the effectiveness of the proposed tactile device for appropriate stiffness of soft human tissues such as liver, the repulsive force and relaxation stress were measured and discussed as a function of the magnetic field intensity. In addition, the effectiveness and practical applicability of the proposed tactile device have been validated through the psychophysical test.

scholarly journals Tribological Evolution of the Superficial Layer and the Effects of the Magnetic Field to a Non- conventional Treated Steel, During Wear Tests

2018 ◽  
Vol 55 (3) ◽  
pp. 442-446
Author(s):  
Carmen Penelopi Papadatu ◽  
Andrei Victor Sandu ◽  
Marian Bordei ◽  
Ioan Gabriel Sandu ◽  
Sorin Ciortan
Keyword(s):  
Magnetic Field ◽  
Mechanical Properties ◽  
Dry Friction ◽  
Experimental Tests ◽  
Superficial Layer ◽  
Alloyed Steel ◽  
Wear Process ◽  
The Magnetic Field ◽  
Wear Tests ◽  
Made In

The article focuses on the behavior of the non-conventional treated alloyed steel in magnetic field, during the dry wear tests. It is a review of the experimental tests from last years. The thermo-magnetic treatments have been applied before the application of a thermo-chemical treatment in plasma based on diffusion process. The study was made in order to improve the mechanical properties of the alloyed steel during the friction wear. Thermo-magnetic treatment applied before the plasma nitro-carburizing treatment improves the mechanical properties of the material especially in this case, for a steel that has a considerable content of Chromium (1.02%). The behavior was studied using X-Ray diffractometry of the superficial layers during the dry friction of wear process. The wear tests used an Amsler machine, during three hours of wear tests. After each hour of the wear tests the samples have been analyzed. The diffractometric characteristics of the superficial layers obtained after a complex array of thermo-magnetic and thermo-chemical in plasma treatments, the phases distribution, the content of the superficial layers and the behavior of the steel during the wear through dry friction tests, have been considered as criteria.

scholarly journals Electromagnetic system for detection and localization of the miners caught by accident in mine

2016 ◽  
Author(s):  
Vira Pronenko ◽  
Fedir Dudkin
Keyword(s):  
Magnetic Field ◽  
Inverse Problem ◽  
Low Frequency ◽  
Emergency Situation ◽  
Field Measurements ◽  
Experimental Tests ◽  
Problem Solution ◽  
Electromagnetic System ◽  
Field Source ◽  
The Magnetic Field

Abstract. The profession of a miner is one of the most dangerous in the world. Among the main causes of the fatalities in the underground coal mines is the untimely alerting of the accident, as well as the lack of information for the rescuers about the actual location of the miners after the accident. In an emergency situation (failure or destruction of underground infrastructure), personnel search behind and beneath of blockage should be provided urgently. But none of the standard technologies (RFID, DECT, WiFi, emitting cable), which use the stationary technical devices in mines, provides the information about the people location caught by accident with necessary precision. The only technology that is able to provide guaranteed delivery of messages about the accident to the mine personnel, regardless of their location and under any destruction in the mine, is low-frequency radio technology able to operate through the thickness of rocks even if it is wet. The proposed new system for miners localization is based on solving the inverse problem that allows the magnetic field source coordinates determining using the data of magnetic field measurements. This approach is based on the measurement of the magnetic field radiated by the miner's responder beacon using two fixed and spaced three-component magnetic field receivers and next the inverse problem solution. As a result, the working model of the system for miner's beacon search and localization (MILES – miner's location emergency system) was developed and successfully tested. The paper presents the peculiarities of this development and the results of experimental tests.

Analysis and Experimental Evaluation of Inherent Instability in Electromagnetic Eddy-Current Dampers Intended for Reducing Lateral Vibration of Rotating Machinery

1995 ◽  
Author(s):  
Yuri Kligerman ◽  
Asif Grushkevich ◽  
Mark S. Darlow ◽  
Adrian Zuckerberger
Keyword(s):  
Magnetic Field ◽  
Eddy Current ◽  
High Speed ◽  
Experimental Tests ◽  
Rotating Machinery ◽  
Lateral Vibration ◽  
Negative Effect ◽  
Eddy Current Damper ◽  
Analytical Approaches ◽  
The Magnetic Field

Abstract There have been a number of papers published that concern the design and operation of electromagnetic, eddy-current dampers for controlling lateral vibration of rotating machinery. Many of these papers have included analysis approaches and all have been generally effective for low-speed operations. There have been a few reports concerning high-speed (supercritical) operations and many of these have indicated instability problems, but none of these have provided a valid analysis to account for instability. That is, all of the analytical approaches have ignored the disk rotation, relative to the magnetic field, and no obvious sources of instability have been found. In this paper, we will present our work in which we have rederived the analyses of this system in which we have not made the common assumption of no rotation between the disk and the magnetic field. In this case, the potential of instability for supercritical speed operation is clear and, in fact, the equivalent negative damping contribution of the eddy-current damper, under these conditions, has a negative effect on the system even if not fully unstable. We have carefully performed a series of experimental tests which corroborate this analytical approach. Finally, we briefly discuss alternative eddy-current damper design approaches that could be considered to provide effective damping at all speeds and avoid these instability problems.

scholarly journals Electromagnetic system for detection and localization of miners caught in mine accidents

2016 ◽  
Vol 5 (2) ◽  
pp. 561-566 ◽  
Author(s):  
Vira Pronenko ◽  
Fedir Dudkin
Keyword(s):  
Magnetic Field ◽  
Inverse Problem ◽  
Radio Frequency Identification ◽  
Emergency Situation ◽  
Field Measurements ◽  
Experimental Tests ◽  
Problem Solution ◽  
Electromagnetic System ◽  
Field Source ◽  
The Magnetic Field

Abstract. The profession of a miner is one of the most dangerous in the world. Among the main causes of fatalities in underground coal mines are the delayed alert of the accident and the lack of information regarding the actual location of the miners after the accident. In an emergency situation (failure or destruction of underground infrastructure), personnel search behind and beneath blockage needs to be performed urgently. However, none of the standard technologies – radio-frequency identification (RFID), Digital Enhanced Cordless Telecommunications (DECT), Wi-Fi, emitting cables, which use the stationary technical devices in mines – provide information about the miners location with the necessary precision. The only technology that is able to provide guaranteed delivery of messages to mine personnel, regardless of their location and under any destruction in the mine, is low-frequency radio technology, which is able to operate through the thickness of rocks even if they are wet. The proposed new system for miner localization is based on solving the inverse problem of determining the magnetic field source coordinates using the data of magnetic field measurements. This approach is based on the measurement of the magnetic field radiated by the miner's responder beacon using two fixed and spaced three-component magnetic field receivers and the inverse problem solution. As a result, a working model of the system for miner's beacon search and localization (MILES – MIner's Location Emergency System) was developed and successfully tested. This paper presents the most important aspects of this development and the results of experimental tests.

Analytical and Experimental Evaluation of Instability in Rotordynamic System With Electromagnetic Eddy-Current Damper

1998 ◽  
Vol 120 (1) ◽  
pp. 272-278 ◽  
Author(s):  
Y. Kligerman ◽  
A. Grushkevich ◽  
M. S. Darlow
Keyword(s):  
Magnetic Field ◽  
Eddy Current ◽  
High Speed ◽  
Experimental Tests ◽  
Disk Rotation ◽  
Negative Effect ◽  
Eddy Current Damper ◽  
All Speeds ◽  
Analytical Approaches ◽  
The Magnetic Field

There have been a number of papers published that concern the design and operation of electromagnetic, eddy-current dampers for controlling lateral vibration of rotating machinery. Many of these papers have included analysis approaches and all have been generally effective for low-speed operations. There have been a few reports concerning high-speed (supercritical) operations and many of these have indicated instability problems, but none of these have provided a valid analysis to account for instability. That is, all of the analytical approaches have ignored the disk rotation, relative to the magnetic field, and no obvious sources of instability have been found. In this paper, we will present our work in which we have rederived the analyses of this system in which we have not made the common assumption of no rotation between the disk and the magnetic field. In this case, the potential of instability for supercritical speed operation is clear and, in fact, the equivalent negative damping contribution of the eddy-current damper, under these conditions, has a negative effect on the system even if not fully unstable. We have carefully performed a series of experimental tests which corroborate this analytical approach. Finally, we briefly discuss alternative eddy-current damper design approaches that could be considered to provide effective damping at all speeds and avoid these instability problems.

scholarly journals Investigation and Modeling of the Magnetic Nanoparticle Aggregation with a Two-Phase CFD Model

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4871
Author(s):  
Péter Pálovics ◽  
Márton Németh ◽  
Márta Rencz
Keyword(s):  
Magnetic Field ◽  
Magnetic Nanoparticle ◽  
Domain Model ◽  
Cfd Model ◽  
Nanoparticle Aggregation ◽  
Two Phase ◽  
Particle Chain ◽  
Particle Chains ◽  
The Impact ◽  
The Magnetic Field

In this paper the magnetic nanoparticle aggregation procedure in a microchannel in the presence of external magnetic field is investigated. The main goal of the work was to establish a numerical model, capable of predicting the shape of the nanoparticle aggregate in a magnetic field without extreme computational demands. To that end, a specialized two-phase CFD model and solver has been created with the open source CFD software OpenFOAM. The model relies on the supposed microstucture of the aggregate consisting of particle chains parallel to the magnetic field. First, the microstructure was investigated with a micro-domain model. Based on the theoretical model of the particle chain and the results of the micro-domain model, a two-phase CFD model and solver were created. After this, the nanoparticle aggregation in a microchannel in the field of a magnet was modeled with the solver at different flow rates. Measurements with a microfluidic device were performed to verify the simulation results. The impact of the aggregate on the channel heat transfer was also investigated.

An Experimental Investigation of Magnetorheological (MR) Fluids under Quasi-Static Loadings

2011 ◽  
Vol 495 ◽  
pp. 285-288 ◽  
Author(s):  
Saiful Amri Mazlan ◽  
Izwan Ismail ◽  
Mohamad S. Fathi ◽  
Shuib Rambat ◽  
Samsol F. Anis
Keyword(s):  
Magnetic Field ◽  
Experimental Investigation ◽  
Systematic Investigation ◽  
Test Equipment ◽  
Structure Transformation ◽  
Carrier Fluid ◽  
Mr Fluids ◽  
Three Stages ◽  
Particle Chains ◽  
The Magnetic Field

In our earlier work, test equipment has been designed, simulated and fabricated to perform experiment on MR fluids in squeeze mode. Preliminary results were gathered and presented for the purpose of validating the test equipment. Therefore, in this paper, a further systematic investigation of MR fluids in squeeze mode has been carried out. As a result, MR fluids experienced rheological changes in three stages during compression and tension. Fluid-particles separation phenomenon was the main caused for the unique behaviour of MR fluids. Particle chains depended on the structure transformation in which the carrier fluid movement can be controlled by changing the magnetic field strength.

Design and Performance Evaluation of Tactile Device Using MR Fluid

2013 ◽  
Vol 278-280 ◽  
pp. 117-120
Author(s):  
Jin Kyu Kim ◽  
Seung Bok Choi
Keyword(s):  
Magnetic Field ◽  
Minimally Invasive Surgery ◽  
Potential Candidate ◽  
Body Parts ◽  
Mr Fluid ◽  
Remarkable Feature ◽  
Magnetic Analysis ◽  
And Performance ◽  
Repulsive Forces ◽  
The Magnetic Field

This paper proposes a novel type of tactile device using magnetorheological (MR) fluid which can be applied in minimally invasive surgery (MIS) robotic system. The remarkable feature of rheological properties of MR fluid by the intensity of the magnetic field makes this potential candidate of the tactile device. As the first step, in order to determine proper input magnetic field the repulsive forces of the real body parts such as hand and neck are measured. Secondly, an appropriate size of the tactile device is designed and manufactured base on magnetic analysis. The final step of this study is to measure the repulsive forces of dividing 5 areas in the tactile device.

Observing the galactic magnetic field

1967 ◽  
Vol 31 ◽  
pp. 375-380
Author(s):  
H. C. van de Hulst
Keyword(s):  
Magnetic Field ◽  
Fair Agreement ◽  
Solar Neighbourhood ◽  
Galactic Magnetic Field ◽  
The Magnetic Field

Various methods of observing the galactic magnetic field are reviewed, and their results summarized. There is fair agreement about the direction of the magnetic field in the solar neighbourhood:l= 50° to 80°; the strength of the field in the disk is of the order of 10-5gauss.

Evolution of Large-Scale Coronal Structures

1994 ◽  
Vol 144 ◽  
pp. 29-33
Author(s):  
P. Ambrož
Keyword(s):  
Magnetic Field ◽  
Field Line ◽  
Large Scale ◽  
Coronal Magnetic Field ◽  
Source Surface ◽  
Solar Cycles ◽  
Characteristic Relationship ◽  
The Magnetic Field ◽  
Coronal Structures

AbstractThe large-scale coronal structures observed during the sporadically visible solar eclipses were compared with the numerically extrapolated field-line structures of coronal magnetic field. A characteristic relationship between the observed structures of coronal plasma and the magnetic field line configurations was determined. The long-term evolution of large scale coronal structures inferred from photospheric magnetic observations in the course of 11- and 22-year solar cycles is described.Some known parameters, such as the source surface radius, or coronal rotation rate are discussed and actually interpreted. A relation between the large-scale photospheric magnetic field evolution and the coronal structure rearrangement is demonstrated.

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