Magnetic properties of natural weakly magnetic iron oxides of the Kursk Magnetic Anomaly

2020 ◽  
pp. 3-9
Author(s):  
T. N. Gzogyan ◽  
◽  
S. R. Gzogyan ◽  
Keyword(s):  
Magnetic Properties ◽  
Iron Oxides ◽  
Magnetic Particles ◽  
Magnetic Characteristics ◽  
Genetic Characteristics ◽  
Natural Systems ◽  
Wide Range ◽  
Low Mass ◽  
Weakly Magnetic ◽  
Ferruginous Quartzites

This paper contains the results of complex studies on magnetic characteristics of a system of basic natural weakly magnetic iron oxides isolated from the oxidized ferruginous quartzites of the KMA. It has been shown that their magnetic characteristics vary over a wide range and substantially depend on the nature of the samples, i.e. represent not only physical, but also genetic characteristics. The contrast in magnetic properties inside the system exceeds the mere hydroxides/quartz contrast; therefore, it is necessary to differentiate the recovery conditions for various iron oxides. For example, the magnetic characteristics of martite and hematite behave differently in different size classes. This dependence is most noteworthy for hematite. It has been shown that, despite the relatively low mass fraction of the ferromagnet, magnetic susceptibility of natural systems of weakly magnetic iron oxides may be an important genetic and diagnostic trait, which must be taken into account when designing all respective separation technology and equipment. The problem under consideration is directly related to mineral processing and the technology must ensure the recovery of both coarse and fine highly and medium magnetic particles into the concentrate.

scholarly journals Microstructure and magnetic properties of Nd-Fe-B-(Re, Ti) alloys

Nukleonika ◽  
2015 ◽  
Vol 60 (1) ◽  
pp. 29-33
Author(s):  
Mariusz Hasiak
Keyword(s):  
Magnetic Properties ◽  
Phase Composition ◽  
Volume Fraction ◽  
Magnetic Characteristics ◽  
Ti Alloys ◽  
Wide Range ◽  
Magnetically Hard ◽  
Ti Addition ◽  
Microstructure And Magnetic Properties

Abstract The microstructure and magnetic properties of nanocomposite hard magnetic Nd-Fe-B-(Re, Ti) materials with different Nd and Fe contents are studied. The role of Re and Ti addition in phase composition and volume fraction of the Nd-Fe-B phase is determined. All samples are annealed at the same temperature of 993 K for 10 min. Mössbauer spectroscopy shows that the addition of 4 at.% of Re to the Nd8Fe78B14 alloy leads to creation of an ineligible amount of the magnetically hard Nd2Fe14B phase. Moreover, the microstructure and magnetic characteristics recorded in a wide range of temperatures for the Nd8Fe79−xB13Mx (x = 4; M = Re or Ti) alloys are also analyzed.

Study on Influence of Microstructure and Thermal Treatment on Magnetic Losses from Non-Oriented Silicon Electrical Steel

2017 ◽  
Vol 15 (13) ◽  
pp. 12-17
Author(s):  
Elena Valentina Stoian ◽  
Maria Cristiana Enescu ◽  
Vasile Bratu ◽  
Carmen Otilia Rusanescu ◽  
Florina Violeta Anghelina
Keyword(s):  
Magnetic Properties ◽  
Electrical Steel ◽  
Aging Treatment ◽  
Magnetic Characteristics ◽  
Magnetic Losses ◽  
Current Frequency ◽  
Steel Sheets ◽  
Wide Range ◽  
Steel Processing ◽  
Hot Rolled

AbstractNon/oriented electrical sheets are sheets tailored to produce specific properties and are produced from Fe-Si or Fe-Si-Al alloys. Non-oriented electrical steel sheets are incorporated into a wide range of equipment, from the simplest domestic appliances to hybrid and pure electric vehicles. In studying about the magnetic, there have a lot of method can be used for the different experiment requirement such as measuring magnetic flux, nominal loss and other objectives.During electrical steel processing, there are usually small variations in both chemical composition and thickness in the hot-rolled material that may lead to different magnetic properties for the same steel grade. Therefore, it is of great importance to know the effects of such variations on the final microstructure and magnetic properties of these steels. The purpose of this work was to study microstructural changes of the bands investigated during processing occurring siliceous strips with non-oriented grains. The second aim was to study the influence of grain size on the total magnetic losses at 1.0 T and 1.5 T. Materials 10 rolls intended to be processed into quality electrical steel M400-50A (according to EN 100027-1) were analyzed with metallographic microscope Neophet 32 and the magnetic characteristics was made with Epstein frame according IEC 6040/4-2, with an exiting current frequency of 50Hz at 1.5T and 1.0T induction after aging treatment of 225°C for 24 hours. Sample for light microscopy observation were prepared by polishing and etching in 5% Nital.

Bimodal Fluorescent and Magnetic Nanoparticles Based on Carbon Quantum Dots and Metal-Carbon Nanocomposites for Bio-Applications

2016 ◽  
Vol 683 ◽  
pp. 454-461 ◽  
Author(s):  
Artem Minin ◽  
Ilya Byzov ◽  
Mikhail Uimin ◽  
Anatoly Ye. Ermakov ◽  
Nina Shchegoleva ◽  
...  
Keyword(s):  
Cell Culture ◽  
Quantum Dots ◽  
Magnetic Properties ◽  
Magnetic Particles ◽  
Disease Diagnosis ◽  
Carbon Quantum Dots ◽  
In Situ Monitoring ◽  
Insulator Layer ◽  
Wide Range

The simultaneous combination of optical and magnetic properties of nanoparticles would greatly benefit in vivo disease diagnosis as well as in situ monitoring of cell in cell culture. The most promising application of magnetic particles in biomedicine is MRI contrast enhancement and magnetic hyperthermia. Another important thing is the determination of exact localization of nanoparticles in the cell culture that can be defined by e.g. optical way. In our investigation we used the iron nanoparticles encapsulated in carbon as a magnetic component and carbon quantum dots as an optical labels to provide the photostability and fluorescence in a wide range of wavelengths. In order to avoid the fluorescence quenching in bimodal particles the optical and magnetic components should be separated by insulator layer. To create the optimal bimodal nanoparticles for this purpose the non-typical configuration of nanocomposites was realized, namely, a fluorescent core was separated from the coated magnetic particles by silicon dioxide matrix. Finally, it was shown that these bimodal nanocomposites demonstrate the high magnetic properties, good visualized ability and low toxicity for living cells as well.

scholarly journals Stages of technological process of high anisotropy formation of magnetic properties under «dry» pressing of powder products

2020 ◽  
Vol 329 ◽  
pp. 02033
Author(s):  
Yuri Vernigorov ◽  
Valeriy Lebedev ◽  
Irina Davidova ◽  
Lydianna Chunakhova ◽  
Yuri Korolkov
Keyword(s):  
Magnetic Energy ◽  
Magnetic Characteristics ◽  
Powder Materials ◽  
Dry Powder ◽  
Fluidized State ◽  
Wide Range ◽  
Wet Pressing ◽  
Dry Pressing ◽  
Powder Pressing ◽  
Low Mass

The article proposes the description of technological production process of anisotropic products from powders of high materials which provides powders preparation and products made of them. It has been shown that the main drawback of «wet» pressing technology is low accuracy at dosing wet charge. To eliminate warping and cracking of briquettes obtained by «wet» pressing during the sintering, they are subjected to air drying at room temperature within 48-72 hours. However, the percentage of product failure due to mechanical and magnetic characteristics remains high. Practically all the drawbacks of «wet» pressing can be eliminated by reverse to dry powder pressing, which allows to obtain low mass magnets without additional final finishing machining, to avoid warping and cracking of the product, and to reduce sintering time. Nevertheless, under the dry powder pressing the magnetic characteristics of products are significantly lower than under the wet pressing. When working with disperse materials, a promising direction is to converse them into fluidized state. To obtain the fluidized state of powder materials, vibrational technologies are used, involving the transfer of a wide range of energy to the powder material, i.e. mechanical, acoustic, electric and magnetic energy.

Magnetic Characterization of CoFe2O4 Nanoparticles

2003 ◽  
Vol 789 ◽  
Author(s):  
G. Lawes ◽  
B. Naughton ◽  
D. R. Clark ◽  
A. P. Ramirez ◽  
R. Seshadri
Keyword(s):  
Magnetic Properties ◽  
Magnetic Nanoparticles ◽  
Ac Susceptibility ◽  
Measurement Techniques ◽  
Anomalous Behavior ◽  
Magnetic Characteristics ◽  
Magnetic Characterization ◽  
Wide Range ◽  
Co Precipitation

We have synthesized CoFe2O4 nanoparticles with length scales ranging from 3.5 nm to 14.2 nm. We have characterized the magnetic properties of these samples using both DC and AC magnetization, and find some slightly anomalous behavior in two of the samples. We tentatively attribute these features to interactions between the magnetic nanoparticles.There is a great deal of interest in understanding the physical basis for the magnetic properties of nanoparticles in order to facilitate their incorporation into a wide range of commercial applications. By studying the magnetic characteristics of CoFe2O4 nanoparticles using bulk measurement techniques, we are able to probe the properties of both the individual nanoparticles and interactions in these systems. In this report, we discuss our magnetic characterization of a series of CoFe2O4 nanoparticles grown using an aqueous co-precipitation technique. In addition to DC magnetization at fixed fields and temperatures, we also investigated the magnetic properties using AC susceptibility measurements. The long term goal of this research is to understand interparticle interactions in magnetic nanoparticles.

Changes of Magnetic Characteristics of iron Oxides and Hydroxides in Aqueous Medium

2017 ◽  
Vol 39 (1) ◽  
pp. 46-52
Author(s):  
T. SAVCHENKO ◽  
◽  
A. GRECHANOVSKY ◽  
A. BRIK ◽  
N. DUDCHENKO
Keyword(s):  
Aqueous Medium ◽  
Iron Oxides ◽  
Magnetic Characteristics

scholarly journals Impact of Iron on the Fe–Co–Ni Ternary Nanocomposites Structural and Magnetic Features Obtained via Chemical Precipitation Followed by Reduction Process for Various Magnetically Coupled Devices Applications

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 341
Author(s):  
Tien Hiep Nguyen ◽  
Gopalu Karunakaran ◽  
Yu.V. Konyukhov ◽  
Nguyen Van Minh ◽  
D.Yu. Karpenkov ◽  
...  
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Reduction Process ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Magnetic Characteristics ◽  
Reduction Temperature ◽  
Fe Content ◽  
Magnetic Features ◽  
Co Precipitation

This paper presents the synthesis of Fe–Co–Ni nanocomposites by chemical precipitation, followed by a reduction process. It was found that the influence of the chemical composition and reduction temperature greatly alters the phase formation, its structures, particle size distribution, and magnetic properties of Fe–Co–Ni nanocomposites. The initial hydroxides of Fe–Co–Ni combinations were prepared by the co-precipitation method from nitrate precursors and precipitated using alkali. The reduction process was carried out by hydrogen in the temperature range of 300–500 °C under isothermal conditions. The nanocomposites had metallic and intermetallic phases with different lattice parameter values due to the increase in Fe content. In this paper, we showed that the values of the magnetic parameters of nanocomposites can be controlled in the ranges of MS = 7.6–192.5 Am2/kg, Mr = 0.4–39.7 Am2/kg, Mr/Ms = 0.02–0.32, and HcM = 4.72–60.68 kA/m by regulating the composition and reduction temperature of the Fe–Co–Ni composites. Due to the reduction process, drastic variations in the magnetic features result from the intermetallic and metallic face formation. The variation in magnetic characteristics is guided by the reduction degree, particle size growth, and crystallinity enhancement. Moreover, the reduction of the surface spins fraction of the nanocomposites under their growth induced an increase in the saturation magnetization. This is the first report where the influence of Fe content on the Fe–Co–Ni ternary system phase content and magnetic properties was evaluated. The Fe–Co–Ni ternary nanocomposites obtained by co-precipitation, followed by the hydrogen reduction led to the formation of better magnetic materials for various magnetically coupled device applications.

scholarly journals Phylogeographic Investigation of an Endangered Longhorn Beetle, Callipogon relictus (Coleoptera: Cerambycidae), in Northeast Asia: Implications for Future Restoration in Korea

Insects ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 555
Author(s):  
Ji-Hyoun Kang ◽  
Dae-Am Yi ◽  
Alexander V. Kuprin ◽  
Chang-Do Han ◽  
Yeon-Jae Bae
Keyword(s):  
South Korea ◽  
Mitochondrial Gene ◽  
Northeast Asia ◽  
Haplotype Network ◽  
Conservation Strategies ◽  
Genetic Characteristics ◽  
Linear Pattern ◽  
Wide Range ◽  
Longhorn Beetle ◽  
High Level

The longhorn beetle, Callipogon (Eoxenus) relictus Semenov, is the only remnant species found in the Palearctic region, while all other Callipogon species are distributed mainly in Central America and partly in South America. This species has been placed in the first category (as ‘critically endangered’) of the Red Data Book in Russia and designated as one of the top-priority target species among all endangered invertebrate species for restoration in South Korea since 2006. Although its restricted distribution in Northeast Asia with a high conservational value has been highlighted, genetic features of C. relictus from different geographic regions remain unexplored. We first investigated the level of genetic diversity and phylogeographic patterns of C. relictus to evaluate the current conservational status and the feasibility of the implementation of a restoration program. The average genetic divergence of mitochondrial gene COI based on Kimura-2-parameter distance among the four regions in Russia, China, North Korea, and South Korea was 2.2%, which lies within the range of intraspecific levels. However, two separate clades with 3.8% divergence were identified, despite no geographical clustering of haplotypes. The linear pattern of the haplotype network with a high level of haplotype and nucleotide diversities suggests that the wide range of currently fragmented populations might be the remnant of genetically diverse populations in the past. This study will provide crucial information on the genetic characteristics and phylogeographic history of C. relictus, which will help to establish conservation strategies for this cherished insect species in Northeast Asia.

Suppression of Ferromagnetism in EuxCa1-xB6

2012 ◽  
Vol 190 ◽  
pp. 97-100 ◽  
Author(s):  
V.V. Glushkov ◽  
A.V. Kuznetsov ◽  
I. Sannikov ◽  
A.V. Bogach ◽  
S.V. Demishev ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Curie Temperature ◽  
Single Crystals ◽  
Effective Magnetic Moment ◽  
Paramagnetic State ◽  
Low Field ◽  
Wide Range ◽  
Free Ion ◽  
The Eu

We report the magnetic properties of EuxCa1-xB6 single crystals (0.756x1) studied in the wide range of temperatures (1.8-300 K) and magnetic fields (up to 50 kOe). It was found that low field magnetic susceptibility χ (T) follows the Curie-Weiss law χ~(T-Θp)-1 at high temperatures for all the concentrations studied. The effective magnetic moment of the Eu2+ ion estimated from the data diminishes from the free ion value μeff7.93μB (μB - Bohr magneton) for x=1 to μeff7.3μB for x=0.756. A universal behavior of magnetic susceptibility χ~(T-Θ)-α (α=1.5) is detected close to the Curie temperature TC in the paramagnetic state at both metallic (x>xC~0.8) and dielectric (xC.

scholarly journals Multi-stable composite twisting structure for morphing applications

2012 ◽  
Vol 468 (2141) ◽  
pp. 1230-1251 ◽  
Author(s):  
X. Lachenal ◽  
P. M. Weaver ◽  
S. Daynes
Keyword(s):  
Analytical Model ◽  
Material Properties ◽  
Degrees Of Freedom ◽  
Design Parameters ◽  
Engineering Structures ◽  
The Past ◽  
Wide Range ◽  
Morphing Structure ◽  
Low Mass ◽  
Unstable States

Conventional shape-changing engineering structures use discrete parts articulated around a number of linkages. Each part carries the loads, and the articulations provide the degrees of freedom of the system, leading to heavy and complex mechanisms. Consequently, there has been increased interest in morphing structures over the past decade owing to their potential to combine the conflicting requirements of strength, flexibility and low mass. This article presents a novel type of morphing structure capable of large deformations, simply consisting of two pre-stressed flanges joined to introduce two stable configurations. The bistability is analysed through a simple analytical model, predicting the positions of the stable and unstable states for different design parameters and material properties. Good correlation is found between experimental results, finite-element modelling and predictions from the analytical model for one particular example. A wide range of design parameters and material properties is also analytically investigated, yielding a remarkable structure with zero stiffness along the twisting axis.

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