scholarly journals Insights into fluidic endogenous magnetism and magnetic monopoles from a liquid metal droplet machine

Soft Science ◽  
2021 ◽  
Author(s):  
Ying-Xin Zhou ◽  
Jia-Sheng Zu ◽  
Jing Liu
Keyword(s):  
Magnetic Field ◽  
Liquid Metal ◽  
Magnetic Particles ◽  
Magnetic Monopole ◽  
Liquid Metals ◽  
Magnetic Monopoles ◽  
Theoretical Interpretation ◽  
Liquid Gallium ◽  
Dynamic Adjustment ◽  
Metal Machine

Magnetism and magnetic monopoles are among the most classical issues in physics. Conventional magnets are generally composed of rigid materials and may face challenges in extreme situations. Here, as an alternative to rigid magnets, we propose, for the first time, the generation of fluidic endogenous magnetism and construct a magnetic monopole through tuning with a liquid metal machine. Based on theoretical interpretation and conceptual experimental observations, we illustrate that when liquid metals, such as gallium alloy, in a solution rotate under electrical actuation, they form an endogenous magnetic field inside. This explains the phenomenon where two such discrete metal droplets can easily fuse together, indicating their reciprocal attraction via the N and S poles. Furthermore, we reveal that a self-fueled liquid metal motor also runs as an endogenous fluidic magnet owing to the electromagnetic homology. When aluminum is added to liquid gallium in solution, it forms a spin motor and dynamically variable charge distribution that produces endogenous magnetism inside. This explains the common phenomena where reflective collision and attractive fusion between running liquid metal motors occur, which are partially caused by the dynamic adjustment of their N and S polarities, respectively. On this basis, more experimental approaches capable of generating dynamic electrical fields also work for the same target. Finally, we propose that such a fluidic endogenous magnet could lead to a magnetic monopole and four technical routes to realize this are suggested. The first involves matching the interior flow of liquid metal machines. The second is the superposition between an external electric effect and the magnetic field. The third route involves composite construction between magnetic particles and a liquid metal spin motor. Finally, chemical methods, such as via galvanic cell reactions, are proposed. Overall, the present theory and identified experimental evidence illustrate the role of a liquid metal machine as a fluidic endogenous magnet and highlight promising methods for the realization of magnetic monopoles. A group of unconventional magnetoelectric devices and applications could therefore be possible in the near future.

Thermal Property Enhancement of Liquid Metal Used As Thermal Interface Material by Mixing Magnetic Particles

2019 ◽  
Author(s):  
Xianfeng Ma ◽  
Gen Li ◽  
Xuelin Zheng ◽  
Xiaozhong Wang ◽  
Zhongcheng Wang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Thermal Conductivity ◽  
Liquid Metal ◽  
Magnetic Particles ◽  
Nickel Particle ◽  
Field Application ◽  
Thermal Interface Material ◽  
Thermal Interface ◽  
Micro Particles ◽  
Steady State Method

Abstract The usage of low melting temperature alloys (LMAs) as thermal interface materials (TIMs) has attracted more and more attention for their high thermal conductivity. However, the wettability between liquid metal and ordinary metal surface was poor, which results in high thermal interface resistance. The thermal and physical properties of LMAs can be modified by adding nano or micro particles. In this study, the room temperature liquid metal (gallium, indium and tin eutectic) was used as TIM and its properties were modified by mixing magnetic nickel particles. Further, the effects of magnetic field application on the thermal performance of modified LMAs were evaluated by steady state method with specially designed sample holder. Results showed that the thermal conductivity of liquid metal mixed with nickel particle increased from 27.33 W/(m · K) to 33.33 W/(m · K) with the application of magnetic field.

Liquid Metal Free Surface Motion Submerged in an AC Magnetic Field

2007 ◽  
Vol 561-565 ◽  
pp. 1071-1074
Author(s):  
Kazuhiko Iwai ◽  
Shigeo Asai
Keyword(s):  
Magnetic Field ◽  
Free Surface ◽  
Liquid Metal ◽  
Standing Wave ◽  
Skin Layer ◽  
Alternating Magnetic Field ◽  
Liquid Gallium ◽  
Field Frequency ◽  
Surface Motion ◽  
The Magnetic Field

Free surface motion of a liquid metal submerged in an alternating magnetic field has been examined. A copper vessel filled with a liquid gallium is set in a coil for the imposition of the alternating magnetic field. The alternating magnetic field penetrates into a liquid gallium only from an upper free surface because thickness of the copper vessel is larger than the electromagnetic skin layer of copper. Time variation of displacement of the standing wave loop excited on the free surface is detected by a laser level sensor. The standing wave was suppressed not only by intensification of the magnetic field magnitude but also increase of the magnetic field frequency.

Forces in Liquid Metal Contacts

2014 ◽  
Author(s):  
Lars Duggen ◽  
Stefan Mátéfi-Tempfli
Keyword(s):  
Liquid Metal ◽  
Liquid Metals ◽  
Tensile Force ◽  
Liquid Gallium ◽  
Metal Contacts ◽  
Circular Symmetry ◽  
Capillary Bridges

Using rather well known theory about capillary bridges between two electrodes we calculate the tensile force that can be applied to liquid metal contacts in the micrometer regime. Assuming circular symmetry, full wetting of the electrodes, and neglecting gravity, we present a brief review of the necessary theory and find numerically the forces to be in the 100μN range for liquid metals as mercury and liquid Gallium suspended between electrodes of 20μm radius.

Magnetic Field Effect on the Natural Convection of a Liquid Metal in a Horizontal Cylinder

2013 ◽  
Author(s):  
Z. H. Wang ◽  
S. Yang ◽  
H. Chen
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Natural Convection ◽  
Liquid Metal ◽  
Horizontal Cylinder ◽  
Movement Direction ◽  
Liquid Gallium ◽  
Induced Current ◽  
Convection And Heat Transfer ◽  
The Magnetic Field

Magneto-hydrodynamic (MHD) effects are widely exploited in different industrial processes. MHD play an essential role in nuclear fusion, where it is involved in the behavior of the liquid metal alloys employed in some of the currently considered designs of tritium breeding blankets. Results of numerical simulations are presented for the natural convection of a liquid metal placed in a horizontal cylinder in the presence of a vertical magnetic field. When there is an additional magnetic field, an induced current is produced by the movement of the liquid metal in a magnetic field. Induced current and magnetic field interaction produced a Lorentz force which is opposite to the movement direction and inhibits the natural convection and heat transfer intensity. The numerical results show that the magnetic field has a observable effect at the heat transfer process of the liquid metal natural convection in a horizontal cylinder. An interesting effect of the magnetic field during the internal flow is the deceleration of the flow velocity for liquid Gallium. The magnetic field in the horizontal radial direction, which is perpendicular to the natural convection caused by the temperature gradient all the while, has the most significant influence on the natural convection, while the influence on the axial direction is comparatively weak in medium magnetic field. With the increase of the intensity of magnetic field, the inhibition is more obvious.

scholarly journals A general approach to composites containing nonmetallic fillers and liquid gallium

2021 ◽  
Vol 7 (1) ◽  
pp. eabe3767
Author(s):  
Chunhui Wang ◽  
Yan Gong ◽  
Benjamin V. Cunning ◽  
Seunghwan Lee ◽  
Quan Le ◽  
...  
Keyword(s):  
Liquid Metal ◽  
Electromagnetic Interference ◽  
Volume Fraction ◽  
Liquid Metals ◽  
Liquid Gallium ◽  
Shielding Effectiveness ◽  
Metallic Particles ◽  
Thermal Paste ◽  
Fit For Purpose ◽  
Electromagnetic Interference Shielding Effectiveness

We report a versatile method to make liquid metal composites by vigorously mixing gallium (Ga) with non-metallic particles of graphene oxide (G-O), graphite, diamond, and silicon carbide that display either paste or putty-like behavior depending on the volume fraction. Unlike Ga, the putty-like mixtures can be kneaded and rolled on any surface without leaving residue. By changing temperature, these materials can be stiffened, softened, and, for the G-O–containing composite, even made porous. The gallium putty (GalP) containing reduced G-O (rG-O) has excellent electromagnetic interference shielding effectiveness. GalP with diamond filler has excellent thermal conductivity and heat transfer superior to a commercial liquid metal–based thermal paste. Composites can also be formed from eutectic alloys of Ga including Ga-In (EGaIn), Ga-Sn (EGaSn), and Ga-In-Sn (EGaInSn or Galinstan). The versatility of our approach allows a variety of fillers to be incorporated in liquid metals, potentially allowing filler-specific “fit for purpose” materials.

scholarly journals Liquid Metal Flow under Traveling Magnetic Field: Solidification Simulation and Pulsating Flow Analysis

2020 ◽  
Author(s):  
Evgeniy Shvydkiy ◽  
Egbert Baake ◽  
Diana Köppen
Keyword(s):  
Magnetic Field ◽  
Liquid Metal ◽  
Neutron Radiography ◽  
Liquid Metals ◽  
Metal Flow ◽  
Flow Analysis ◽  
Electromagnetic Stirring ◽  
Pulsation Frequency ◽  
Conductive Liquid ◽  
Traveling Magnetic Field

Non steady applied magnetic field impact on a liquid metals has good prospects for industry. For a better understanding of heat and mass transfer processes under these circumstances, numerical simulations are needed. A combination of finite elements and volumes methods was used to calculate the flow and solidification of liquid metal under electromagnetic influence. Validation of numerical results was carried out by means of measuring with ultrasound Doppler velocimetry technique, as well as with neutron radiography snapshots of the position and shape of the solid/liquid interface. As a result of the first part of the work, a numerical model of electromagnetic stirring and solidification was developed and validated. This model could be an effective tool for analyzing the electromagnetic stirring during the solidification process. In the second part, the dependences of the velocity pulsation amplitude and the melt velocity maximum value on the magnetic field pulsation frequency are obtained. It was found numerically the ability of the pulsating force action to develop higher values of the liquid metal velocity at a frequency close to the MHD resonance. Obtained characteristics give a more detailed description of the electrically conductive liquid behaviour under action of pulsating traveling magnetic field.

Rotating thermal convection in liquid gallium: multi-modal flow, absent steady columns

2018 ◽  
Vol 846 ◽  
pp. 846-876 ◽  
Author(s):  
Jonathan M. Aurnou ◽  
Vincent Bertin ◽  
Alexander M. Grannan ◽  
Susanne Horn ◽  
Tobias Vogt
Keyword(s):  
Liquid Metal ◽  
Thermal Convection ◽  
Convective Flow ◽  
Laboratory Experiments ◽  
Liquid Metals ◽  
Low Frequency ◽  
Working Fluid ◽  
Liquid Gallium ◽  
Thermally Driven ◽  
Convective Motions

Earth’s magnetic field is generated by convective motions in its liquid metal core. In this fluid, the heat diffuses significantly more than momentum, and thus the Prandtl number$Pr$is well below unity. The thermally driven convective flow dynamics of liquid metals are very different from moderate-$Pr$fluids, such as water and those used in current dynamo simulations. In order to characterise rapidly rotating thermal convection in low-$Pr$number fluids, we have performed laboratory experiments in a cylinder of aspect ratio$\unicode[STIX]{x1D6E4}=1.94$using liquid gallium ($Pr\simeq 0.025$) as the working fluid. The Ekman number varies from$E\simeq 5\times 10^{-6}$to$5\times 10^{-5}$and the Rayleigh number varies from$Ra\simeq 2\times 10^{5}$to$1.5\times 10^{7}$. Using spectral analysis stemming from point-wise temperature measurements within the fluid and measurements of the Nusselt number$Nu$, we characterise the different styles of low-$Pr$rotating convective flow. The convection threshold is first overcome in the form of container-scale inertial oscillatory modes. At stronger forcing, sidewall-attached modes are identified for the first time in liquid metal laboratory experiments. These wall modes coexist with the bulk oscillatory modes. At$Ra$well below the values where steady rotating columnar convection occurs, the bulk flow becomes turbulent. Our results imply that rotating convective flows in liquid metals do not develop in the form of quasisteady columns, as in moderate-$Pr$fluids, but in the form of oscillatory convective motions. Thus, thermally driven flows in low-$Pr$geophysical and astrophysical fluids can differ substantively from those occurring in$Pr\simeq 1$models. Furthermore, our experimental results show that relatively low-frequency wall modes are an essential dynamical component of rapidly rotating convection in liquid metals.

Movement of liquid gallium dispersing low concentration of temperature sensitive magnetic particles under magnetic field

2011 ◽  
Vol 323 (10) ◽  
pp. 1207-1210 ◽  
Author(s):  
Toyohisa Fujita ◽  
Hyun-Seo Park ◽  
Kenji Ono ◽  
Seiji Matsuo ◽  
Katsunori Okaya ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Particles ◽  
Liquid Gallium ◽  
Temperature Sensitive ◽  
Low Concentration

scholarly journals Theoretical Studies on the Creation of Artificial Magnetic Monopoles

2021 ◽  
Author(s):  
Shinichi Ishiguri
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Maxwell Equation ◽  
Magnetic Monopole ◽  
Energy Gap ◽  
Magnetic Monopoles ◽  
Magnetic Potential ◽  
Discussion Section ◽  
Dependent Relationship ◽  
The Creation

The purpose of this paper is to demonstrate the existence of an artificial magnetic monopole and to introduce new electromagnetic equations by altering an electric field and a magnetic field vectors.As a principle device, a cylindrical condenser is prepared, and a superconducting loop is inserted into it. By this conduction, radial electric fields take a role as the centripetal force and both counterclockwise and clockwise motions are induced. As a result, a stationery wave is formed in which the nodes take a part in creating a monopole as follows.First, employing the Lorentz conservations and because node of the stationary wave has no phases, the momentum k and the vector potential A vanish and instead a magnetic potential appears in order to maintain the Lorentz conservation. This magnetic potential has relationship with an electric potential, and thus consequently, a dependent relationship is obtained between an electric field and a magnetic field vectors. Using this conclusive dependent relationship, we can derive new Maxwell equation assembly which are created by altering the electric field and the magnetic field vectors. In this process, we derive a divergent equation of magnetic fields which is not zero, i.e., the existence of a magnetic monopole. Employing these newly derived Maxwell equation, an electromagnetic wave is derived whose speed is the same as one the existing Maxwell equations provide. As a monopole configuration, this paper discusses the energy gap of the vacuum, which is a result of the Dirac equation and describes a monopole as pairs between two Cooper pairs (i.e. four electrons) whose interaction is a photon. As mentioned, because the total momenta and phases are zero, this paper defines the wave function as the Dirac function and demonstrate the condensation, employing the Bloch’s theorem. Moreover, using the macroscopic basic equations, we retrace the creation of the divergent magnetic field in view of macroscopic phenomenon., which provides results in this paper.In Result section in this paper, we succeeded in demonstrating the distribution of the divergent magnetic field of monopole in terms of both microscopic and macroscopic scales. Furthermore, Discussion section describes properties a magnetic monopole should follow.

Analysis of magneto rheological elastomers for energy harvesting systems

2020 ◽  
Vol 64 (1-4) ◽  
pp. 439-446
Author(s):  
Gildas Diguet ◽  
Gael Sebald ◽  
Masami Nakano ◽  
Mickaël Lallart ◽  
Jean-Yves Cavaillé
Keyword(s):  
Magnetic Field ◽  
Energy Harvesting ◽  
Shear Strain ◽  
Magnetic Induction ◽  
Magnetic Particles ◽  
Homogeneous Magnetic Field ◽  
Electrical Signal ◽  
Harvesting Systems ◽  
Dc Bias ◽  
Magneto Rheological

Magneto Rheological Elastomers (MREs) are composite materials based on an elastomer filled by magnetic particles. Anisotropic MRE can be easily manufactured by curing the material under homogeneous magnetic field which creates column of particles. The magnetic and elastic properties are actually coupled making these MREs suitable for energy conversion. From these remarkable properties, an energy harvesting device is considered through the application of a DC bias magnetic induction on two MREs as a metal piece is applying an AC shear strain on them. Such strain therefore changes the permeabilities of the elastomers, hence generating an AC magnetic induction which can be converted into AC electrical signal with the help of a coil. The device is simulated with a Finite Element Method software to examine the effect of the MRE parameters, the DC bias magnetic induction and applied shear strain (amplitude and frequency) on the resulting electrical signal.

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