scholarly journals Experimental Study of Sidewall Pressure Induced by Ferroparticles in Fluid under a Pulsating Magnetic Field

Fluids ◽  
2020 ◽  
Vol 5 (2) ◽  
pp. 98
Author(s):  
Or Werner ◽  
Asaf Azulay ◽  
Boris Mikhailovich ◽  
Avi Levy
Keyword(s):  
Magnetic Field ◽  
Carbonyl Iron ◽  
Polyvinylidene Fluoride ◽  
Particle Interaction ◽  
Cardiac Pacing ◽  
Field Exposure ◽  
Water Chamber ◽  
The Masses ◽  
Fluoride Sensor ◽  
The Magnetic Field

For several decades, magnetic nano- and microparticles have been used in various applications, as they can be attracted and controlled using external magnetic fields. Recently, carbonyl iron microparticles were used in a feasibility study of a new cardiac pacing application. The particles were inserted into a heart, attracted to its sidewall using a pulsating magnetic field, and applied pulsating pressure on its sidewall. The magnitude of the sidewall pressure is a critical parameter for the success and safety of the application, and it was evaluated analytically using a simplified model. In the present study, the behaviour of carbonyl iron microparticles in a water chamber was studied experimentally. Several masses of these particles were attracted to the sidewall of the chamber using an external pulsating magnetic field; the behaviours of the masses of particles, the particle–particle interaction, and the influence of fluid dynamics on them were examined during different periods of pulses. The sidewall pressure during their attraction was measured using an in-house piezoelectric polyvinylidene fluoride sensor. The relations between the measured sidewall pressure and the mass of the particles, their sizes, and the magnetic field exposure time were investigated. The obtained results suggest an asymptotic sidewall pressure value for the specified magnetic field. The measurements of the sidewall pressure are compared with evaluated results from the analytical model, showing that the model over-predicts the sidewall pressure.

Brownian Dynamics Simulations of Aggregation Phenomena in a Magnetic Particle Suspension With an Alternating Magnetic Field (Relationship Between the Aggregate Structure and the Heat Production)

2018 ◽  
Author(s):  
Seiya Suzuki ◽  
Akira Satoh ◽  
Muneo Futamura
Keyword(s):  
Magnetic Field ◽  
Heat Production ◽  
Brownian Dynamics ◽  
Magnetic Particle ◽  
Particle Interaction ◽  
Alternating Magnetic Field ◽  
Dynamics Simulations ◽  
Brownian Dynamics Simulations ◽  
The Magnetic Field ◽  
Aggregation Phenomena

The present study addresses physical phenomena of a suspension composed of magnetic spherical particles in an alternating magnetic field in order to elucidate particle aggregation phenomena and their influence on heat production. For this objective, we have performed Brownian dynamics simulations in a variety of circumstances of the magnetic field strength and frequency of an alternating magnetic field, and the magnetic dipole-dipole interaction strength. As in a time-independent uniform external magnetic field, large aggregates are formed in the case of strong magnetic particle-particle interactions. However, these clusters exhibit completely different behaviors that are dependent on the frequency of an alternating magnetic field. If the frequency is significantly high, then the viscous torque is the dominant factor, so that the formation of the clusters is not significantly influenced by the time-dependent magnetic field. If the frequency is significantly low, the magnetic field have a significant effect on the rotational motion of the particles, so that the formation of the cluster is dependent on which factor dominates the particle motion between the applied magnetic field and the magnetic particle-particle interaction. If the magnetic interaction is more dominant than the external field, stable chain-like clusters are formed in the field direction, and the magnetic particle-particle interaction induces a significant delay for the moments inclining in the alternating magnetic field direction. This behavior gives rise to a hysteresis loop with a larger area and therefore a large heating effect is obtained.

scholarly journals Open charm and charmonium states in strong magnetic fields

2021 ◽  
pp. 2150064
Author(s):  
Amruta Mishra ◽  
S. P. Misra
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Constituent Quark ◽  
Open Charm ◽  
Charm Mesons ◽  
Strong Magnetic Fields ◽  
Decay Widths ◽  
State Formula ◽  
The Masses ◽  
The Magnetic Field

The mass modifications of the open charm ([Formula: see text] and [Formula: see text]) mesons, and their effects on the decay widths [Formula: see text] as well as of the charmonium state, [Formula: see text] to open charm mesons ([Formula: see text]), are investigated in the presence of strong magnetic fields. These are studied accounting for the mixing of the pseudoscalar ([Formula: see text]) and vector ([Formula: see text]) mesons ([Formula: see text], [Formula: see text] mixings), with the mixing parameter, [Formula: see text] of a phenomenological three-point ([Formula: see text]) vertex interaction determined from the observed radiative decay width of [Formula: see text]. For charged [Formula: see text] mixing, this parameter is dependent on the magnetic field, because of the Landau level contributions to the vacuum masses of these mesons. The masses of the charged [Formula: see text] and [Formula: see text] mesons modified due to [Formula: see text] mixing, in addition, have contributions from the lowest Landau levels in the presence of a strong magnetic field. The effects of the magnetic field on the decay widths are studied using a field theoretical model of composite hadrons with quark (and antiquark) constituents. The matrix elements for these decays are evaluated using the light quark–antiquark pair creation term of the free Dirac Hamiltonian for the constituent quark field, with explicit constructions for the charmonium state [Formula: see text], the open charm ([Formula: see text], [Formula: see text], [Formula: see text]) mesons and the pion states in terms of the constituent quark fields. The parameter for the charged [Formula: see text] mixing is observed to increase appreciably with increase in the magnetic field. This leads to dominant modifications to their masses, and hence the decay widths of charged [Formula: see text] as well as [Formula: see text] at large values of the magnetic field. The modifications of the masses and decay widths of the open and hidden charm mesons in the presence of strong magnetic fields should have observable consequences on the production of the open charm ([Formula: see text] and [Formula: see text]) mesons as well as of the charmonium states resulting from noncentral ultra-relativistic heavy ion collision experiments.

Tuning Active Magnetorheological Elastomers for Damping Applications

2010 ◽  
Vol 636-637 ◽  
pp. 766-771 ◽  
Author(s):  
Anna Boczkowska ◽  
Stefan F. Awietjan
Keyword(s):  
Magnetic Field ◽  
Carbonyl Iron ◽  
Volume Fraction ◽  
Iron Particles ◽  
Magnetorheological Elastomers ◽  
Ferromagnetic Component ◽  
Electron And Light Microscopy ◽  
Tan Δ ◽  
Microscopy Techniques ◽  
The Magnetic Field

Magnetorheological elastomers (MREs) were obtained by mixing soft polyurethane and carbonyl-iron particles. The effect of the volume fraction of the ferromagnetic particles on the MREs microstructure and properties, as well as their arrangement in relation to the external magnetic field were investigated. As a ferromagnetic component carbonyl–iron powder, with particle size from 6-9µm, was used. The amount of the carbonyl iron particles was varied from 1.5 to 33.0 %(v/v). The samples were produced with randomly dispersed and aligned carbonyl iron particles. Scanning electron and light microscopy techniques were used for the MRE microstructure observations. The rheological properties (G’, G’’ and tan δ) of the MRE were tested without and with the application of the magnetic field. It was found that the microstructure of MREs, particularly the amount and arrangement of the carbonyl-iron particles, has a significant influence on their rheological and damping properties.

scholarly journals Enhanced Magnetorheological Performance of Carbonyl Iron Suspension Added With Barium Ferrite Nanoparticle

2021 ◽  
Vol 8 ◽  
Author(s):  
Hyo Seon Jang ◽  
Qi Lu ◽  
Hyoung Jin Choi
Keyword(s):  
Magnetic Field ◽  
Carbonyl Iron ◽  
Barium Ferrite ◽  
Flow Behavior ◽  
Vibrating Sample Magnetometry ◽  
Mr Fluid ◽  
Mr Fluids ◽  
Ferrite Nanoparticle ◽  
The Magnetic Field ◽  
Mr Characteristics

Hard-magnetic barium ferrite (BF) nanoparticles with a hexagonal plate-like structure were used as an additive to a carbonyl iron (CI) microparticle-based magnetorheological (MR) fluid. The morphology of the pristine CI and CI/BF mixture particles was examined by scanning electron microscopy. The saturation magnetization and coercivity values of each particle were measured in the powder state by vibrating sample magnetometry. The MR characteristics of the CI/BF MR fluid measured using a rotation rheometer under a range of magnetic field strengths were compared with those of the CI-based MR fluid. The flow behavior of both MR fluids was fitted using a Herschel–Bulkley model, and their stress relaxation phenomenon was examined using the Schwarzl equation. The MR fluid with the BF additive showed higher dynamic and elastic yield stresses than the MR fluid without the BF additive as the magnetic field strength increased. Furthermore, the BF nanoparticles embedded in the space between the CI microparticles improved the dispersion stability and the MR performance of the MR fluid.

scholarly journals Impact of Magnetic Field Strengthening on Combustion Performance of Low-Octane Fuel in Two-Stroke Engine

2020 ◽  
Vol 16 (1) ◽  
pp. 57-62
Author(s):  
N. A. Wibowo ◽  
S. M. Utami ◽  
C. A. Riyanto ◽  
A. Setiawan
Keyword(s):  
Magnetic Field ◽  
Near Infrared ◽  
Vibrational Energy ◽  
Field Exposure ◽  
Magnetic Field Exposure ◽  
Combustion Performance ◽  
Molecular Behavior ◽  
Exponential Decrease ◽  
Low Magnetic Field ◽  
The Magnetic Field

The impacts of strengthening magnetic field exposure on combustion performance of low-octane fuel have been examined experimentally. The combustion test was carried out using a 2-stroke 49 cc engine where the fuel was magnetized using a low magnetic field (<2 kG). Moreover, the molecular behavior of magnetized fuel was also characterized through spectrum tests using NIR and UV-Vis spectrophotometers. The result of this study indicates an exponential decrease of magnetized fuel consumption against the strengthening of magnetic field exposure. This exponential decrease of consumption can be related to the Arrhenius principle. In addition, the decrease of oxygen in the exhaust gas along with the strengthening of the magnetic field also confirms the increase of combustion reactions. Meanwhile, the increase of magnetized fuel absorption against ultraviolet and near-infrared lights along with the increase of the magnetic field intensity indicates a bond weakening, accompanied by the increase of molecular vibrational energy.

scholarly journals A Study among Community Living Underneath SUTET about The General Health Condition and The Electromagnetic Fields Exposures

2009 ◽  
Vol 4 (2) ◽  
pp. 57
Author(s):  
Corrie Wawolumaya ◽  
Djoko Darwanto
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Field ◽  
Electric Field ◽  
Physical Examination ◽  
General Health ◽  
Urban Poor ◽  
Health Condition ◽  
Field Exposure ◽  
General Health Condition ◽  
The Magnetic Field

SUTET or the Extra High Voltage Transmission Line of 500 kV has passed through larger residential areas in the community. The aim of study is to provide the description of general health condition of community residing under SUTET in the urban poor of Jakarta and surrounding. The design of study was cross sectional, carried out among 1200 respondents which were taken stratified proportional purposively, based on zones of the electromagnetic field exposures. Data were collected through observation, interview and physical examination. The electric field and the magnetic field exposures were separately measured outside and inside the houses. The highest electromagnetic field exposures were measured at one meter height above the ground , for the electric field 3,1 kV/m. and the magnetic field 550 mA/m or 687,5.10-3µT, were identified in zone 1 0-20 ms. The magnetic field was decreasing gradually through zone2 300mA/m and nearing zero in zone 3. Both the highest electric field and the magnetic field exposures were below the threshold values stated by SNI 2003, 5 kV/m dan 0,1 mT or 80.104 mA/m (note: 1 A/m = 1,25 µT). The highest electric field exposure was identified at one meter height from the ground 2,5 kV/m at 02.00–03.00 hours a.m and the highest magnetic field 2400 mA/m at 12.00-16.00 hours p.m. The biggest portion of houses was poor ( 30 %) were beinghoused for morethan 30 years. The major diseases were found similar in all zones i.e., dental diseases, myopia and hypertension.Keywords: SUTET, zones, physical examination, 10 major diseases.AbstrakJaringan SUTET Perusahaan Listrik Negara banyak melalui daerah pemukiman. Tujuan penelitian mendapatkan gambaran kesehatan penduduk yang bermukim di bawah SUTET dan di daerah urban miskin Jakarta dan sekitarnya. Penelitian disain kroseksional ini dilakukan pada sample 1200 kepala keluarga yang ditarik secara stratifikasi proportional purposif berdasarkan zona kuat medan elektromagnet. Data dikumpulkan dengan metoda observasi, wawancara dan pemeriksaan kesehatan. Kuat medan listrik dan medan magnet diukur terpisah di luar rumah, dan di dalam rumah. Ditemukan kuat medan listrik tertinggipada ketinggian 1 meter di atas tanah 3,1 kV/m. Kuat medan magnet 550 mA/m atau 687,5.10-3µT diidentifikasi dalam zona 1 0-20 m yang menurun be-rangsur pada zona 2 300mA/m dan mendekati 0 pada zona 3. Medan listrik dan medan magnet berada di bawah nilai ambang SNI 2003, 5 kV/m dan 0,1 mT atau 80.104 mA/m (note: 1 A/m = 1,25 µT). Medan listrik tertinggi ditemukan pada ketinggian 1 meter dari tanah 2,5 kV/m pada jam 02.00–03.00 pagi danmedan magnet ttinggi 2400 mA/m pada jam 12.00-16.00 .Jenis rumah terbanyak adalah rumah kumuh ( 30 %) telah dimukimi lebih 30 tahun. Penyakit uta-ma di semua zona adalah gangguan gigi geligi, myopia dan hipertensi yang tidak berbeda antara zona.Kata kunci : SUTET, zona, kondisi kesehatan, 10 penyakit utama.

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