scholarly journals Rotational Diode: Clockwise/Counterclockwise Asymmetry in Conducting and Mechanical Properties of Rotating (semi)Conductors

Symmetry ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1569
Author(s):  
M. N. Chernodub
Keyword(s):  
Magnetic Field ◽  
Mechanical Properties ◽  
Quantum Effects ◽  
Angular Frequency ◽  
Metallic Film ◽  
Moments Of Inertia ◽  
Classical Object ◽  
The Magnetic Field

It is difficult to imagine an isolated classical object which possess different moments of inertia when it is uniformly rotated about the same axis with the same angular frequency in opposite, clockwise and counterclockwise, directions. We argue that due to quantum effects, certain (semi-) conductors should exhibit asymmetry in their mechanical and conducting properties with respect to the opposite rotations. We show that a cylinder made of a suitably chosen semiconductor, coated in a metallic film and placed in the magnetic-field background, can serve as a “rotational diode”, which conducts electricity only at a specific range of angular frequencies. The critical angular frequency and the direction of rotation can be tuned with the magnetic field’s strength. Mechanically, the rotational diode possesses different moments of inertia when rotated in clockwise and counterclockwise directions. These effects emerge as a particularity of the Fermi-Dirac statistics of electrons in rotating conductors.

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 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.

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.

Analytical and Experimental Study of Magnetomechanical Properties of Magnetic Porous PDMS Sponge Under Non-Uniform Magnetic Fields

2020 ◽  
Vol 87 (8) ◽  
Author(s):  
Ali Shademani ◽  
Mu Chiao
Keyword(s):  
Magnetic Field ◽  
Mechanical Properties ◽  
Experimental Study ◽  
Magnetic Fields ◽  
Field Gradient ◽  
Magnetic Field Gradient ◽  
Experimental Methods ◽  
Compression Tests ◽  
Magnetomechanical Coupling ◽  
The Magnetic Field

Abstract Magnetic elastomers (MEs) respond to an applied magnetic field through magnetomechanical coupling, where the mechanical properties of the MEs change with magnetic field strength. These phenomena have been mostly studied under homogenous magnetic fields due to the simplicity. In this work, the effects of the magnetic field gradient on the mechanical properties and the response of the MEs was examined. MEs are made by embedding carbonyl iron microparticles (CI) into a polydimethylsiloxane (PDMS) matrix, which is later rendered porous. The influence of the CI concentration was investigated by manipulating four different samples with CI/PDMS weight ratios of 0.2, 0.6, 1.0, and 1.4. An analytical method was proposed to further understand the interactions of the magnetic field gradient and the material’s response. The proposed theory was later verified with experimental results from compression tests in the presence of different magnetic fields. The proposed theoretical framework and experimental methods can be used to improve the design of MEs in the future.

Influence of Quantum Effects on the Magnetic Field Behavior in Overdense Plasma

2018 ◽  
Vol 26 (1) ◽  
pp. 56-62 ◽  
Author(s):  
M. K. Khadivi Borougeni ◽  
L. Rajaei ◽  
A. Gharaati ◽  
S. Miraboutalebi
Keyword(s):  
Magnetic Field ◽  
Quantum Effects ◽  
Field Behavior ◽  
Overdense Plasma ◽  
The Magnetic Field

The Evaluation of Absorption Performance of Magneto-Rheological (MR) Elastomer

2015 ◽  
Vol 1095 ◽  
pp. 483-489
Author(s):  
Kwang Hee Lee ◽  
Kyung Sik Jung ◽  
Chul Hee Lee
Keyword(s):  
Magnetic Field ◽  
Mechanical Properties ◽  
Impact Test ◽  
Impact Load ◽  
Time Duration ◽  
Shock Absorption ◽  
Absorption Performance ◽  
Magneto Rheological ◽  
Drop Impact Test ◽  
The Magnetic Field

This study examines the relation between the thickness of a specimen and the weight of an impactor for evaluating the shock absorption performance of magneto-rheological (MR) elastomers with and without a magnetic field. The shock absorption performance can be evaluated by calculating impact energy. The MR elastomer is a smart material and its mechanical properties change under the influence of a magnetic field. The drop impact test is performed to evaluate the amount of shock absorption of the MR elastomer for each test condition. Tests are also performed by varying the magnetic field during impact to improve the shock absorption performance of the MR elastomer, which is related to impact load. The results show a better shock absorption performance with a thicker MR elastomer, lighter impactor, and without a magnetic field. Also, the magnitude of impact and the time duration for stabilization are improved when the magnetic field is varied during the test.

A Nonintrusive Method of Measuring the Local Mechanical Properties of Soft Hydrogels Using Magnetic Microneedles

2008 ◽  
Vol 131 (2) ◽  
Author(s):  
Uday Chippada ◽  
Bernard Yurke ◽  
Penelope C. Georges ◽  
Noshir A. Langrana
Keyword(s):  
Magnetic Field ◽  
Mechanical Properties ◽  
Field Gradient ◽  
Type I Collagen ◽  
Zero Magnetic Field ◽  
Arbitrary Field ◽  
Type I ◽  
Collagen Gels ◽  
Field Gradients ◽  
The Magnetic Field

Soft hydrogels serving as substrates for cell attachment are used to culture many types of cells. The mechanical properties of these gels influence cell morphology, growth, and differentiation. For studies of cell growth on inhomogeneous gels, techniques by which the mechanical properties of the substrate can be measured within the proximity of a given cell are of interest. We describe an apparatus that allows the determination of local gel elasticity by measuring the response of embedded micron-sized magnetic needles to applied magnetic fields. This microscope-based four-magnet apparatus can apply both force and torque on the microneedles. The force and the torque are manipulated by changing the values of the magnetic field at the four poles of the magnet using a feedback circuit driven by LABVIEW. Using Hall probes, we have mapped out the magnetic field and field gradients produced by each pole when all the other poles are held at zero magnetic field. We have verified that superposition of these field maps allows one to obtain field maps for the case when the poles are held at arbitrary field values. This allows one to apply known fields and field gradients to a given microneedle. An imaging system is employed to measure the displacement and rotation of the needles. Polyacrylamide hydrogels of known elasticity were used to determine the relationship between the field gradient at the location of the needles and the force acting on the needles. This relationship allows the force on the microneedle to be determined from a known field gradient. This together with a measurement of the displacement of the needle in a given gel allows one to determine the stiffness (F∕δ) of the gel and the elastic modulus, provided Poison’s ratio is known. Using this method, the stiffness and the modulus of elasticity of type-I collagen gels were found to be 2.64±0.05nN∕μm and 284.6±5.9Pa, respectively. This apparatus is presently being employed to track the mechanical stiffness of the DNA-cross-linked hydrogels, developed by our group, whose mechanical properties can be varied on demand by adding or removing cross-linker strands. Thus a system that can be utilized to track the local properties of soft media as a function of time with minimum mechanical disturbance in the presence of cells is presented.

Nonlinear Magnetostrictive Effect of Magnetorheological Elastomers

2013 ◽  
Vol 833 ◽  
pp. 291-294 ◽  
Author(s):  
Shu Lei Sun ◽  
Xiong Qi Peng ◽  
Zao Yang Guo
Keyword(s):  
Magnetic Field ◽  
Mechanical Properties ◽  
Finite Element ◽  
Volume Fraction ◽  
Nonlinear Function ◽  
Measured Data ◽  
Magnetorheological Elastomers ◽  
Smart Composites ◽  
Element Simulation ◽  
The Magnetic Field

Magnetorheological elastomers (MREs) are a class of smart composites whose mechanical properties can be obviously changed under different magnetic field. Only a few works study its magnetostrictive property, which describes the changes in dimensions of a material in its magnetization. Magnetostriction in the ferromagnetic particle is also called eigenstrain in MREs. It is modeled using the nonlinear function of the magnetization in this article. The eigenstrain due to the magnetostriction is incorporated in the structure of the MREs using a generalized Hookes Law. By means of initial strain, a finite element simulation is presented to describe the magnetostriction of MREs. The results show that the magnetostriction along the magnetic field depends on the magnetization and the volume fraction of particles. As an application, we will present numerical simulations for a magnetostriction and compare these results with measured data.

Sign in / Sign up

Export Citation Format

Share Document