scholarly journals The atomic process in ferromagnetic Induction

1922 ◽  
Vol 100 (706) ◽  
pp. 449-460 ◽  
Keyword(s):  
Magnetic Particles ◽  
Strong Field ◽  
Molecular Magnets ◽  
Magnetic Element ◽  
Atomic Process ◽  
Dissipation Of Energy ◽  
Unstable Phase ◽  
Complete Alignment ◽  
The Stability ◽  
Ferromagnetic Substance

The object of this paper is to amend, in an important particular, the theory of ferromagnetic induction put forward by me more than 30 years ago, and to describe a new model. That theory was itself a modification of the earlier theory of Weber. To Weber is due the fundamental notion that a substance contains minute particles, each of which acts as a magnet, and that in the process of magnetising a ferromagnetic substance these are turned into more or less complete alignment. The ultimate magnetic particles use to be called “molecular magnets”: we now recognise them as attributes of the atom, not of the molecule, and (in all probability) they derive their magnetic moment from the circulation of electricity in electron orbits or in ring electrons. What turns is not the molecule nor the atom, but something within the atom. The characteristics which distinguish ferromagnetic substances from other paramagnetics are: (1) the much larger amount of magnetism they can acquire under the action of an impressed field; (2) the fact that the acquired magnetism tends towards a saturation limit when the field is progressively increased; (3) the fact that the acquired magnetism shows hysteresis with respect to variations of the field, except in certain small initial changes. Weber’s theory explained (1) and (2). My modification of it explained, in addition, (3) as an effect of the irreversible action which occurs when the equilibrium of a magnetic element becomes unstable through change in the externally impressed magnetic force, and it swings over, with dissipation of energy, into a new position of stability. The stability in both positions is sufficiently explained by magnetic forces only. In breaking away from one stable position it is deflected at first in a quasi­-elastic (reversible) manner until the external force reaches a certain value at which the equilibrium is upset. The essence of hysteresis is the turning from one position of stability to another, through a region of instability. If the conditions are such that there is no unstable phase in the turning, then there is no dissipation of energy, and consequently no hysteresis. This occurs in very feeble magnetisation, when the deflections are reversible; it also occurs if the piece be caused to rotate in a field of great strength. J. Swinburne pointed out that, as a consequence of my theory, hysteresis should vanish when a cylinder of ferromagnetic metal is rotated in a very strong field, and this curious result was confirmed experimentally by F. G. Baily.

scholarly journals Quantified abundance of magnetofossils at the Paleocene–Eocene boundary from synchrotron-based transmission X-ray microscopy

2015 ◽  
Vol 112 (41) ◽  
pp. 12598-12603 ◽  
Author(s):  
Huapei Wang ◽  
Jun Wang ◽  
Yu-chen Karen Chen-Wiegart ◽  
Dennis V. Kent
Keyword(s):  
Magnetic Particles ◽  
Strong Field ◽  
Atlantic Coastal Plain ◽  
Magnetic Studies ◽  
Electron Microscopic ◽  
Natural Sediment ◽  
Full Field ◽  
X Ray ◽  
Transmission Electron ◽  
Carbon Isotope Excursion

The Paleocene–Eocene boundary (∼55.8 million years ago) is marked by an abrupt negative carbon isotope excursion (CIE) that coincides with an oxygen isotope decrease interpreted as the Paleocene–Eocene thermal maximum. Biogenic magnetite (Fe3O4) in the form of giant (micron-sized) spearhead-like and spindle-like magnetofossils, as well as nano-sized magnetotactic bacteria magnetosome chains, have been reported in clay-rich sediments in the New Jersey Atlantic Coastal Plain and were thought to account for the distinctive single-domain magnetic properties of these sediments. Uncalibrated strong field magnet extraction techniques have been typically used to provide material for scanning and transmission electron microscopic imaging of these magnetic particles, whose concentration in the natural sediment is thus difficult to quantify. In this study, we use a recently developed ultrahigh-resolution, synchrotron-based, full-field transmission X-ray microscope to study the iron-rich minerals within the clay sediment in their bulk state. We are able to estimate the total magnetization concentration of the giant biogenic magnetofossils to be only ∼10% of whole sediment. Along with previous rock magnetic studies on the CIE clay, we suggest that most of the magnetite in the clay occurs as isolated, near-equidimensional nanoparticles, a suggestion that points to a nonbiogenic origin, such as comet impact plume condensates in what may be very rapidly deposited CIE clays.

Magnetorheological fluid based on amorphous Fe-Si-B alloy magnetic particles

2021 ◽  
pp. 1045389X2110643
Author(s):  
Chuncheng Yang ◽  
Zhong Liu ◽  
Xiangyu Pei ◽  
Cuiling Jin ◽  
Mengchun Yu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Rheological Property ◽  
Magnetic Particles ◽  
Annealing Treatment ◽  
Magnetorheological Fluid ◽  
The Stability ◽  
The Magnetic Field ◽  
Amorphous Particle ◽  
Better Than

Magnetorheological fluids (MRFs) based on amorphous Fe-Si-B alloy magnetic particles were prepared. The influence of annealing treatment on stability and rheological property of MRFs was investigated. The saturation magnetization ( Ms) of amorphous Fe-Si-B particles after annealing at 550°C is 131.5 emu/g, which is higher than that of amorphous Fe-Si-B particles without annealing. Moreover, the stability of MRF with annealed amorphous Fe-Si-B particles is better than that of MRF without annealed amorphous Fe-Si-B particles. Stearic acid at 3 wt% was added to the MRF2 to enhance the fluid stability to greater than 90%. In addition, the rheological properties demonstrate that the prepared amorphous particle MRF shows relatively strong magnetic responsiveness, especially when the magnetic field strength reaches 365 kA/m. As the magnetic field intensified, the yield stress increased dramatically and followed the Herschel-Bulkley model.

scholarly journals Synthesis of Magnetic Targeted Cellulose Composite Decorated with Poly(AA-DMC) for Synergistic Adsorption Degradation of Congo Red from Organic Wastewater

2021 ◽  
Author(s):  
Chen Ling ◽  
Dai Yimin ◽  
Lu Qi ◽  
Fang Chengqian ◽  
Wang Zhiheng ◽  
...  
Keyword(s):  
Congo Red ◽  
Magnetic Particles ◽  
Degradation Mechanism ◽  
Degradation Of Dyes ◽  
Cellulose Composites ◽  
Natural Cellulose ◽  
The Stability ◽  
Adsorption Desorption ◽  
Cr Removal ◽  
Organic Wastewater

Abstract A brand-new environmental-friendly magnetic cellulosic adsorbent MnFe2O4@Cel-g-p(AA-DMC) was synthesized by natural cellulose and easy-recovered magnetic particles MnFe2O4. Magnetic cellulose composites were characterized by SEM, TEM, XPS, XRD, BET, VSM, TGA and FTIR. The MnFe2O4NPs could activate the peroxymonosulfate (PMS) to produce various reactive oxygen species (ROS). Accordingly, magnetic cellulose composites can synergistic adsorption degradation of dyes from organic wastewater. The Congo red (CR) removal efficiency by MnFe2O4@Cel-g-p(AA-DMC) via PMS activated by MnFe2O4 reached a maximum of 96.9% and only 9% reduction after four adsorption-desorption cycles, indicating the stability and recoverability of adsorbent. It is worth noting that adsorbents can be quickly recovered from aqueous solution by external magnet owing to superior saturation magnetization (35.44 emu·g-1). A possible degradation mechanism of CR on the MnFe2O4@Cel-g-p(AA-DMC) composite was proposed. The results suggest that adsorbent display strong potential for the removal of CR dyes from organic wastewater.

Time-Resolved Imaging of Correlation-Driven Charge Migration in Light-Induced Molecular Magnets by X-ray Scattering

2020 ◽  
Author(s):  
Jean-Christophe Tremblay ◽  
Gunter Hermann ◽  
Vincent Pohl ◽  
Gopal Dixit
Keyword(s):  
Molecular Magnets ◽  
Time Dependent ◽  
Electron Dynamics ◽  
Charge Migration ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
Induced Charge ◽  
Time Resolved Imaging ◽  
The Stability

In this contribution, we investigate the effect of correlation-induced charge migration on the stability of light-induced molecular magnets. Laser-driven electron dynamics is simulated using density-matrix based time-dependent configuration interaction. The...

The Stability of Plastic Flow and Dissipation of Energy

1989 ◽  
Vol T29 ◽  
pp. 213-217 ◽  
Author(s):  
Michael Boček
Keyword(s):  
Plastic Flow ◽  
Dissipation Of Energy ◽  
The Stability

scholarly journals Role of inter-particle force between micro and nano magnetic particles on the stability of magnetorheological fluid

AIP Advances ◽  
2017 ◽  
Vol 7 (2) ◽  
pp. 025206 ◽  
Author(s):  
Zarana Laherisheth ◽  
Kinnari Parekh ◽  
R. V. Upadhyay
Keyword(s):  
Magnetic Particles ◽  
Magnetorheological Fluid ◽  
The Stability ◽  
Particle Force

The stability of a colloidal suspension of coated magnetic particles in an aqueous solution

1985 ◽  
Vol 29 (1) ◽  
pp. 11-17 ◽  
Author(s):  
Derek Y. C. Chan ◽  
Douglas Henderson ◽  
Jorge Barojas ◽  
Andrew M. Homola
Keyword(s):  
Aqueous Solution ◽  
Magnetic Particles ◽  
Colloidal Suspension ◽  
The Stability

scholarly journals Aggregation Properties of Albumin in Interacting with Magnetic Fluids

2021 ◽  
Vol 22 (19) ◽  
pp. 10734
Author(s):  
Elena N. Velichko ◽  
Elina K. Nepomnyashchaya ◽  
Maksim A. Baranov ◽  
Alexey N. Skvortsov ◽  
Ivan V. Pleshakov ◽  
...  
Keyword(s):  
Magnetic Nanoparticles ◽  
Magnetic Nanoparticle ◽  
Magnetic Particles ◽  
Correlation Spectroscopy ◽  
Interaction Processes ◽  
Low Concentrations ◽  
Nanoparticle Aggregates ◽  
Magnetite Particles ◽  
Spiral Structures ◽  
The Stability

In this study, interactions of Fe3O4 magnetic nanoparticles with serum albumin biomolecules in aqueous solutions were considered. The studies were conducted with the laser correlation spectroscopy and optical analysis of dehydrated films. It was shown that the addition of magnetite to an albumin solution at low concentrations of up to 10−6 g/L led to the formation of aggregates with sizes of up to 300 nm in the liquid phase and an increase in the number of spiral structures in the dehydrated films, which indicated an increase in their stability. With a further increase in the magnetite concentration in the solution (from 10−4 g/L), the magnetic particles stuck together and to albumin, thus forming aggregates with sizes larger than 1000 nm. At the same time, the formation of morphological structures in molecular films was disturbed, and a characteristic decrease in their stability occurred. Most stable films were formed at low concentrations of magnetic nanoparticles (less than 10−4 g/L) when small albumin–magnetic nanoparticle aggregates were formed. These results are important for characterizing the interaction processes of biomolecules with magnetic nanoparticles and can be useful for predicting the stability of biomolecular films with the inclusion of magnetite particles.

Influence of HLB Parameters of Surfactants on Properties of Magneto-Rheological Fluid

2010 ◽  
Vol 97-101 ◽  
pp. 843-847 ◽  
Author(s):  
Cheng Bin Du ◽  
Wei Qing Chen ◽  
Fa Xue Wan
Keyword(s):  
Magnetic Properties ◽  
Oleic Acid ◽  
Polyethylene Glycol ◽  
Rheological Properties ◽  
Magnetic Particles ◽  
Hydrophilic Lipophilic Balance ◽  
The Stability ◽  
Magneto Rheological

The hydrophilic-lipophilic balance (HLB) parameters of surfactants have a significant effect on properties of surfactants and determine the effects of surfactants. The magneto-rheological fluid (MRF) is prepared by using the two typical HLB parameters of surfactants including Polyethylene Glycol and oleic acid in order to improve the property of MRF. Polyethylene Glycol (PEG) whose HLB parameter is 20 has strong hydrophilic. Oleic acid whose HLB parameter is 1 has strong lipophilic. The results indicate that magnetic properties of magnetic particles and rheological properties of MRF can hardly be changed by adding surfactants. The sedimentary stability of MRF adding lipophilic surfactants is superior to that of MRF adding hydrophilic surfactants, and the stability of MRF adding two surfactants increases significantly.

The Experimental Analysis of Modifier on Fluid Magnetic Abrasivetool

2011 ◽  
Vol 189-193 ◽  
pp. 369-372
Author(s):  
Hong Zhang ◽  
Peng Peng
Keyword(s):  
Experimental Analysis ◽  
Magnetic Particles ◽  
Magnetorheological Fluid ◽  
Sodium Hexametaphosphate ◽  
Nano Silica ◽  
Soft Magnetic ◽  
Important Indicator ◽  
The Stability ◽  
Base Liquid

Fluid magnetic abrasivetool is a kind of suspension, which is composed of soft magnetic particles, surfactants, base liquid and so on so forth, so it can have strong magnetorheological characteristics and grinding characteristics. The stability of magnetorheological fluid is one of the most important indicator to evaluate the quality of magnetorheological fluid. Sodium hexametaphosphate and PAA have perfect function to maintain dispersionstability and retrogradation, adding nano-silica can improve the retrogradation of magnetic abrasivetool, which can modify redispersibility of magnetic abrasivetool.

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