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.

Structural Changes in the Superficial Layers of a Non-conventional Treated Steel Subjected to a Wear Process

2017 ◽  
Vol 68 (10) ◽  
pp. 2329-2333
Author(s):  
Carmen Penelopi Papadatu ◽  
Andrei Victor Sandu ◽  
Marian Bordei ◽  
Ioan Gabriel Sandu
Keyword(s):  
Magnetic Field ◽  
Mechanical Properties ◽  
Chemical Treatment ◽  
Structural Changes ◽  
Alloyed Steel ◽  
X Ray ◽  
Wear Process ◽  
Treated Steel ◽  
Machinery Building ◽  
Made In

It was considered a non - conventional treatment in magnetic field applied before the thermo-chemical treatment (nitro-carburizing in plasma), for one alloyed steel which is used in Machinery building industry. These researches have been made in order to improve the mechanical properties of Chromium-Molybdenum alloyed steel non-conventionally treated in a magnetic field. Through the thermo-magnetic treatment, applied before the plasma nitro-carburizing, the mechanical properties of this material have been improved, especially in this case of the steel with a considered content of Chromium (1.38%). These researches, through X-Ray diffractometry of the behavior of the superficial layers during the dry wear process, completed this work. The diffractometric characteristics of the superficial layers which have been obtained after a complex system of thermo-magnetic treatments followed by a thermo-chemical treatment, the superficial layers content and the behavior of the steel at the wear through dry friction tests were used as criterion. The paper is a review of the researches from the last few years.

Study on the Influence of the Treatment in Magnetic Field on the Nitrided Layer in Plasma

2017 ◽  
Vol 68 (4) ◽  
pp. 675-679 ◽  
Author(s):  
Carmen Penelopi Papadatu ◽  
Andrei Victor Sandu ◽  
Marian Bordei ◽  
Ioan Gabriel Sandu
Keyword(s):  
Magnetic Field ◽  
Complex System ◽  
Mechanical Properties ◽  
Chemical Treatment ◽  
Dry Friction ◽  
Nitrided Layer ◽  
Alloyed Steel ◽  
Hardness Values ◽  
Made In

These researches have been made in order to improve the mechanical properties of a Chromium�Molybdenum alloyed steel non-conventionally treated in a magnetic field. Through the thermo-magnetic treatments, applied before thermo-chemical treatment, the mechanical properties of this material have been improved, especially in the case of a great content of chromium. The hardness values of the superficial layers which have been obtained after a complex system of thermo-magnetic treatments followed by a thermo-chemical treatment, the superficial layers content and the behaviour of the steel at the wear through dry friction tests were used as criterion. The paper is a review of the researches from the last few years.

scholarly journals The Magnetic Field of the Crab as Revealed by New, High Resolution, Multi-Band Radio Images

1990 ◽  
Vol 140 ◽  
pp. 79-80
Author(s):  
M. F. Bietenholz ◽  
P. P. Kronberg
Keyword(s):  
Magnetic Field ◽  
High Resolution ◽  
Crab Nebula ◽  
Radio Observations ◽  
Field Orientation ◽  
Magnetic Field Orientation ◽  
The Crab Nebula ◽  
The Magnetic Field ◽  
Made In ◽  
Multi Band

We present and describe recent radio observations of the Crab Nebula, which allow us to determine the magnetic field orientation and depolarization at unprecedented resolution. The observations were made in 1987-1988 using all four configurations of the VLA, at 1410,1515,4625, and 4885 MHz. The resulting maps were all convolved with a clean beam of 1.8″ × 2.0″, elongated in P.A. 80°, and the residuals added back in.

scholarly journals Discovery of weak magnetic fields in four DZ white dwarfs in the local 20 pc volume

2019 ◽  
Vol 630 ◽  
pp. A65 ◽  
Author(s):  
S. Bagnulo ◽  
J. D. Landstreet
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
White Dwarfs ◽  
Field Measurements ◽  
Weak Magnetic Fields ◽  
Polluted Atmosphere ◽  
Highly Sensitive ◽  
Cool White Dwarfs ◽  
The Magnetic Field ◽  
Made In

We report the discovery of weak magnetic fields in three white dwarfs within the local 20 pc volume (WD 0816−310, WD 1009−184, and WD 1532+129), and we confirm the magnetic nature of a fourth star (WD 2138−332) in which we had previously detected a field at a 3σ level. The spectra of all these white dwarfs are characterised by the presence of metal lines and lack of H and He lines, that is, they belong to the spectral class DZ. The polarisation signal of the Ca II H+K lines of WD 1009−184 is particularly spectacular, with an amplitude of 20% that is due to the presence of a magnetic field with an average line-of-sight component of 40 kG. We have thus established that at least 40% of the known DZ white dwarfs with an He-rich atmosphere contained in the 20 pc volume have a magnetic field, while further observations are needed to establish whether the remaining DZ white dwarfs in the same volume are magnetic or not. Metal lines in the spectra of DZ white dwarfs are thought to have originated by accretion from rocky debris, and it might be argued that a link exists between metal accretion and higher occurrence of magnetism. However, we are not able to distinguish whether the magnetic field and the presence of a polluted atmosphere have a common origin, or if it is the presence of metal lines that allows us to detect a higher frequency of magnetic fields in cool white dwarfs, which would otherwise have featureless spectra. We argue that the new highly sensitive longitudinal field measurements that we have made in recent years are consistent with the idea that the magnetic field appears more frequently in older than in younger white dwarfs.

scholarly journals Effects of Static Magnetic Field on Compression Properties of Mg-Al-Gd Alloys Containing Gd-Rich Ferromagnetic Phase

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4957
Author(s):  
Qi Cai ◽  
Xinyao Li ◽  
Shukui Li ◽  
Chuan He ◽  
Xingwei Liu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Mechanical Properties ◽  
Secondary Phase ◽  
Magnetic Treatment ◽  
Ferromagnetic Phase ◽  
Air Cooling ◽  
Phase Constituent ◽  
Positive Effects ◽  
Compression Properties ◽  
The Magnetic Field

The Mg–0.6Al–20.8Gd (wt.%) alloys were homogenized at 620 °C for 20 min under 0 T and 1 T, followed by furnace cooling, quenching, and air cooling, respectively. The effects of the magnetic field on the phase constituent, microstructure, secondary phase precipitation, and mechanical properties of the Mg–Al–Gd alloys were investigated. The Mg–Al–Gd alloys contained α-Mg, Mg5Gd, Al2Gd, and GdH2 phases, and the phase constituents were hardly influenced by the applied magnetic field. However, the precipitation of the paramagnetic Mg5Gd upon cooling was accelerated by the magnetic field, and that of the ferromagnetic Al2Gd phases was inhibited. In addition, the Al2Gd phase was significantly refined and driven to segregate at the grain boundaries by the magnetic field, and the resultant pinning effect led to the microstructure change from dendritic α-Mg grains to rosette-like ones. When the magnetic field was only applied to the homogenization stage, the content of the Mg5Gd phase remained unchanged in the quenched alloy, whereas the Mg5Gd laths were significantly refined. By contrast, the contents of the Al2Gd and GdH2 phases were increased, while the precipitation sites were still within the α-Mg grains. The Mg5Gd laths were incapable of providing precipitation strengthening, while the Al2Gd and GdH2 particles brought positive effects on the enhancement of the mechanical properties. In the quenching condition, the hardness, compression strength, and ductility can be improved by the magnetic treatment, whereas these mechanical properties can be suppressed in the furnace cooled condition by the magnetic treatment.

scholarly journals Effects of an External Magnetic Field on the Microstructural and Mechanical Properties of the Fusion Zone in TIG Welding

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 714 ◽  
Author(s):  
Anderson Vergílio de Queiroz ◽  
Márcio Teodoro Fernandes ◽  
Leonardo Silva ◽  
Rudineli Demarque ◽  
Carlos Roberto Xavier ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Mechanical Properties ◽  
External Magnetic Field ◽  
Vickers Microhardness ◽  
Mechanical Vibration ◽  
Welding Process ◽  
Charpy Impact ◽  
Delta Ferrite ◽  
Charpy Test ◽  
The Magnetic Field

Welding is a widely used process that requires continuous developments to meet new application demands of mechanical projects under severe conditions. The homogeneity of metallurgical and mechanical properties in welded joints is the key factor for any welding process. The applications of external magnetic fields, mechanical vibration, and ultrasound are the fundamental steps to achieve success in improving these properties. The present work aimed at determining suitable processing conditions to achieve the desired balance between metallurgical and mechanical properties of 304L steel in TIG (Tungsten Inert Gas) welding under the application of an external magnetic field. The microstructural characteristics of the weld bead were analyzed by optical microscopy (OM) and scanning electron microscopy (SEM). In order to evaluate the mechanical properties of the welded specimen, its Vickers microhardness map and Charpy impact energy at −20 °C were obtained. In addition, corrosion tests were carried out in the saline medium to compare the corrosion resistance of the joint with that of the base metal and that without the magnetic field. It was found that the external magnetic field decreased the percentage of delta ferrite, improved the filling of the weld pool with the weld metal, and decreased the primary and secondary dendritic spacings. The Vickers microhardness value under the magnetic field was found to be lower than that without the magnetic field, and the Charpy test showed no significant variation in energy absorption. Moreover, the welded joint produced under the external magnetic field manifested less resistance to corrosion.

ELECTROMAGNETIC FIELDS IN AN N‐LAYER ANISOTROPIC HALF‐SPACE

Geophysics ◽  
1967 ◽  
Vol 32 (4) ◽  
pp. 668-677 ◽  
Author(s):  
Douglas P. O’Brien ◽  
H. F. Morrison
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Plane Wave ◽  
Half Space ◽  
Electric Fields ◽  
Field Measurements ◽  
Large Scatter ◽  
Tensor Impedance ◽  
The Magnetic Field ◽  
Made In

From Maxwell’s equations and Ohm’s law for a horizontally anisotropic medium, it may be shown that two independent plane wave modes propagate perpendicular to the plane of the anisotropy. Boundary conditions at the interfaces in an n‐layered model permit the calculation, through successive matrix multiplications, of the fields at the surface in terms of the fields propagated into the basal infinite half space. Specifying the magnetic field at the surface allows the calculation of the resultant electric fields, and the calculation of the entries of a tensor impedance relationship. These calculations have been programmed for the digital computer and an interpretation of impedances obtained from field measurements may thus be made in terms of the anisotropic layering. In addition, apparent resistivities in orthogonal directions have been calculated for specific models and compared to experimental data. It is apparent that the large scatter of observed resistivities can be caused by small changes in the polarization of the magnetic field.

Magnetosensitive Polymer Composites and Effect of Magnetic Field Directivity on their Properties

2016 ◽  
Vol 251 ◽  
pp. 3-7 ◽  
Author(s):  
Egidijus Dragašius ◽  
Evguenia Korobko ◽  
Zoya Novikava ◽  
Elena Sermyazhko
Keyword(s):  
Magnetic Field ◽  
Mechanical Properties ◽  
Magnetic Properties ◽  
Polymer Composites ◽  
Matrix Material ◽  
Vertical Shear ◽  
Horizontal Shear ◽  
Dispersed Particles ◽  
The Magnetic Field ◽  
Ferromagnetic Particles

Mechanical properties of polymer composite materials, containing ferromagnetic small dispersed particles of carbonyl iron that create structures along force lines of the magnetic field have been investigated. In paper the influence of the polymer matrix material and the orientation of ferromagnetic particles inside it on the properties of polymer composites are considered in the regimes of horizontal shear, vertical shear and periodical (sinusoidal) deformation of the samples. Magnetic properties at the change of magnetic field induction B in the range of 0 to 1 T are determined.

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.

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