Self-biased Dual-phase Energy Harvesting System

2013 ◽  
Vol 1556 ◽  
Author(s):  
Yuan Zhou ◽  
Amar Bhalla ◽  
Shashank Priya
Keyword(s):  
Magnetic Field ◽  
Magnetic Energy ◽  
Synthesis Method ◽  
Three Dimensional ◽  
Deposition Process ◽  
Small Scale ◽  
Dual Phase ◽  
Mems Devices ◽  
Power Sources ◽  
Dc Magnetic Field

ABSTRACTIn this study, we report the design and fabrication of a dual-phase energy harvester which can synchronously harvest both mechanical and magnetic energy in the absence of DC magnetic field. The harvester consists of a magnetostrictive cantilever beam and a magnetostrictive/ piezoelectric (M/P) self-biased laminate composite structure. This structure allows us to utilize piezoelectric and self-biased magnetoelectric effect simultaneously. By combining these mechanisms together, a sum effect for harvesting both magnetic and vibration energy was realized under DC magnetic field free condition. The bilayer structure provides a simplified geometry that can be easily incorporated into MEMS devices. We demonstrate a hybrid synthesis method for fabrication of complex three-dimensional thin films using a cost-effective and mask-less aerosol jet deposition process. The combination of the hybrid aerosol jet process with dual phase harvester design provides the opportunity to fabricate small scale power sources required for structural health monitoring applications.

MAGNETIC FIELD AMPLIFICATION BY RELATIVISTIC SHOCKS IN AN INHOMOGENEOUS MEDIUM

2012 ◽  
Vol 08 ◽  
pp. 364-367
Author(s):  
YOSUKE MIZUNO ◽  
MARTIN POHL ◽  
JACEK NIEMIEC ◽  
BING ZHANG ◽  
KEN-ICHI NISHIKAWA ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Inhomogeneous Medium ◽  
Magnetic Energy ◽  
Small Scale ◽  
Two Dimensional ◽  
Filamentary Structure ◽  
Field Amplification ◽  
Relativistic Shocks ◽  
Field Lines ◽  
Magnetohydrodynamic Simulations

We perform two-dimensional relativistic magnetohydrodynamic simulations of a mildly relativistic shock propagating through an inhomogeneous medium. We show that the postshock region becomes turbulent owing to preshock density inhomogeneity, and the magnetic field is strongly amplified due to the stretching and folding of field lines in the turbulent velocity field. The amplified magnetic field evolves into a filamentary structure in two-dimensional simulations. The magnetic energy spectrum is flatter than the Kolmogorov spectrum and indicates that the so-called small-scale dynamo is occurring in the postshock region. We also find that the amplitude of magnetic-field amplification depends on the direction of the mean preshock magnetic field.

Fast (non-)diffusive Quasi-Geostrophic Magneto-Coriolis Modes in the Earth's core

2021 ◽  
Author(s):  
Felix Gerick ◽  
Dominique Jault ◽  
Jerome Noir
Keyword(s):  
Magnetic Field ◽  
Magnetic Energy ◽  
Three Dimensional ◽  
Outer Core ◽  
Equatorial Region ◽  
Earth’S Core ◽  
Earth's Core ◽  
Strong Focusing ◽  
Geomagnetic Observations ◽  
And Diffusion

<p> Fast changes of Earth's magnetic field could be explained by inviscid and diffusion-less quasi-geostrophic (QG) Magneto-Coriolis modes. We present a hybrid QG model with columnar flows and three-dimensional magnetic fields and find modes with periods of a few years at parameters relevant to Earth's core. These fast Magneto-Coriolis modes show strong focusing of their kinetic and magnetic energy in the equatorial region, while maintaining a relatively large spatial structure along the azimuthal direction. Their properties agree with some of the observations and inferred core flows. We find additionally, in contrast to what has been assumed previously, that these modes are not affected significantly by magnetic diffusion. The model opens a new way of inverting geomagnetic observations to the flow and magnetic field deep within the Earth's outer core.</p>

Development of Thin Metal Film Deposition Process for the Intravascular Catheter

1999 ◽  
Author(s):  
Seok Chung ◽  
Jun Keun Chang ◽  
Dong Chul Han
Keyword(s):  
Metal Film ◽  
Three Dimensional ◽  
Deposition Process ◽  
Medical Application ◽  
Thin Metal Film ◽  
Film Deposition ◽  
Thin Metal ◽  
Mems Devices ◽  
Sensors And Actuators ◽  
Custom Made

Abstract To make some MF.MS devices such as sensors and actuators be useful in the medical application, it is required to integrate this devices with power or sensor lines and to keep the hole devices biocompatible. Integrating micro machined sensors and actuators with conventional copper lines is incompatible because the thin copper lines are not easy to handle in the mass production. To achieve the compatibility of wiring method between MEMS devices, we developed the thin metal film deposition process that coats micropattered thin copper films on the non silicon-wafer substrate. The process was developed with the custom-made three-dimensional thin film sputter/evaporation system. The system consists of process chamber, two branch chambers, substrate holder unit and linear/rotary motion feedthrough. Thin metal film was deposited on the biocompatible polymer, polyurethane (PellethaneR) and silicone, catheter that is 2 mm in diameter and 1,000 mm in length. We deposited Cr/Cu and Ti/Cu layer and made a comparative study of the deposition processes, sputtering and evaporation. The temperature of both the processes were maintained below 100°C, for the catheter not melting during the processes. To use the films as signal lines connect the signal source to the actuator on the catheter tip, we machined the films into desired patterns with the eximer laser. In this paper, we developed the thin metal film deposition system and processes for the biopolymeric substrate used in the medical MEMS devices.

scholarly journals Room temperature giant magnetostriction in single-crystal nickel nanowires

2019 ◽  
Vol 11 (1) ◽  
Author(s):  
Anastasios Pateras ◽  
Ross Harder ◽  
Sohini Manna ◽  
Boris Kiefer ◽  
Richard L. Sandberg ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Single Crystal ◽  
Room Temperature ◽  
Magnetic Energy ◽  
Mechanical Energy ◽  
Three Dimensional ◽  
Local Strain ◽  
Nickel Nanowires ◽  
Giant Magnetostriction

Abstract Magnetostriction is the emergence of a mechanical deformation induced by an external magnetic field. The conversion of magnetic energy into mechanical energy via magnetostriction at the nanoscale is the basis of many electromechanical systems such as sensors, transducers, actuators, and energy harvesters. However, cryogenic temperatures and large magnetic fields are often required to drive the magnetostriction in such systems, rendering this approach energetically inefficient and impractical for room-temperature device applications. Here, we report the experimental observation of giant magnetostriction in single-crystal nickel nanowires at room temperature. We determined the average values of the magnetostrictive constants of a Ni nanowire from the shifts of the measured diffraction patterns using the 002 and 111 Bragg reflections. At an applied magnetic field of 600 Oe, the magnetostrictive constants have values of λ100 = −0.161% and λ111 = −0.067%, two orders of magnitude larger than those in bulk nickel. Using Bragg coherent diffraction imaging (BCDI), we obtained the three-dimensional strain distribution inside the Ni nanowire, revealing nucleation of local strain fields at two different values of the external magnetic field. Our analysis indicates that the enhancement of the magnetostriction coefficients is mainly due to the increases in the shape, surface-induced, and stress-induced anisotropies, which facilitate magnetization along the nanowire axis and increase the total magnetoelastic energy of the system.

scholarly journals Numerical 3-D Simulations of the Collapse of Photospheric Flux Tubes

1983 ◽  
Vol 102 ◽  
pp. 79-83
Author(s):  
Ake Nordlund
Keyword(s):  
Magnetic Field ◽  
Three Dimensional ◽  
Homogeneous Magnetic Field ◽  
Weak Field ◽  
Small Scale ◽  
Back Reaction ◽  
Three Dimensional Model ◽  
Flux Tubes ◽  
Weak Field Limit ◽  
Dynamic Description

The interaction of photospheric granular convection with a small scale magnetic field has been simulated numerically in a three-dimensional model, with an extension of techniques recently used to simulate field-free granulation. The evolution of an initially homogeneous magnetic field was followed numerically, both in a kinematic (weak-field limit) description, and in a dynamic description, where the back-reaction of the field on the motion through the Lorentz force is taken into account. The simulations illustrate the strong tendency for the field to be swept up and concentrated in the inter-granular lanes because of the topology of the granular flow. The convectively unstable stratification allows field concentration up to a kilogauss field because the temperature reduction in the magnetic plasma.

Turbulent relaxation of a confined magnetofluid to a force-free state

1987 ◽  
Vol 37 (2) ◽  
pp. 299-321 ◽  
Author(s):  
Jill P. Dahlburg ◽  
David Montgomery ◽  
Gary D. Doolen ◽  
Leaf Turner
Keyword(s):  
Magnetic Field ◽  
Energy State ◽  
Minimum Energy ◽  
Three Dimensional ◽  
Small Scale ◽  
Current Profile ◽  
Transit Times ◽  
Uniform Current ◽  
Scale Turbulence ◽  
Pseudo Spectral

Three-dimensional, pseudo-spectral computation is used to follow the evolution of a resistive, incompressible magnetofluid. The magnetofluid is confined by rigid, free-slip, perfectly-conducting square boundaries in the x, y directions (‘poloidal’ boundaries), and periodic boundary conditions are assumed in the z direction (‘toroidal’ direction). A constant, uniform d.c. magnetic field B0 is assumed in the z direction and a non-uniform current density j flows along it initially. Starting from a non-equilibrium hollow current profile, the evolution is followed for several tens of Alfvén transit times. Considerable small-scale turbulence develops, which causes energy to decay more rapidly than magnetic helicity. The average toroidal magnetic field at the (x, y) boundary reverses sign spontaneously. The near spatial constancy of the ratio jB/(jB) ≡ cos θ, in the relaxed state at late times, suggests that the state is nearly force-free. However, the ratio j. B/B2 ≡ α is considerably less uniform than is cos θ suggesting more residual disorder than a pure minimum-energy state would display.

Strong MHD helical turbulence and the nonlinear dynamo effect

1976 ◽  
Vol 77 (2) ◽  
pp. 321-354 ◽  
Author(s):  
A. Pouquet ◽  
U. Frisch ◽  
J. Léorat
Keyword(s):  
Large Scale ◽  
Magnetic Energy ◽  
Three Dimensional ◽  
Power Laws ◽  
Inertial Range ◽  
Small Scale ◽  
Mhd Turbulence ◽  
Inverse Cascade ◽  
Small Scales ◽  
Dynamo Effect

To understand the turbulent generation of large-scale magnetic fields and to advance beyond purely kinematic approaches to the dynamo effect like that introduced by Steenbeck, Krause & Radler (1966)’ a new nonlinear theory is developed for three-dimensional, homogeneous, isotropic, incompressible MHD turbulence with helicity, i.e. not statistically invariant under plane reflexions. For this, techniques introduced for ordinary turbulence in recent years by Kraichnan (1971 a)’ Orszag (1970, 1976) and others are generalized to MHD; in particular we make use of the eddy-damped quasi-normal Markovian approximation. The resulting closed equations for the evolution of the kinetic and magnetic energy and helicity spectra are studied both theoretically and numerically in situations with high Reynolds number and unit magnetic Prandtl number.Interactions between widely separated scales are much more important than for non-magnetic turbulence. Large-scale magnetic energy brings to equipartition small-scale kinetic and magnetic excitation (energy or helicity) by the ‘Alfvén effect’; the small-scale ‘residual’ helicity, which is the difference between a purely kinetic and a purely magnetic helical term, induces growth of large-scale magnetic energy and helicity by the ‘helicity effect’. In the absence of helicity an inertial range occurs with a cascade of energy to small scales; to lowest order it is a −3/2 power law with equipartition of kinetic and magnetic energy spectra as in Kraichnan (1965) but there are −2 corrections (and possibly higher ones) leading to a slight excess of magnetic energy. When kinetic energy is continuously injected, an initial seed of magnetic field will grow to approximate equipartition, at least in the small scales. If in addition kinetic helicity is injected, an inverse cascade of magnetic helicity is obtained leading to the appearance of magnetic energy and helicity in ever-increasing scales (in fact, limited by the size of the system). This inverse cascade, predicted by Frischet al.(1975), results from a competition between the helicity and Alféh effects and yields an inertial range with approximately — 1 and — 2 power laws for magnetic energy and helicity. When kinetic helicity is injected at the scale linjand the rate$\tilde{\epsilon}^V$(per unit mass), the time of build-up of magnetic energy with scaleL[Gt ] linjis$t \approx L(|\tilde{\epsilon}^V|l^2_{\rm inj})^{-1/3}.$

On the spontaneous magnetic field in a conducting liquid in turbulent motion

1950 ◽  
Vol 201 (1066) ◽  
pp. 405-416 ◽  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Magnetic Energy ◽  
Turbulent Motion ◽  
Small Scale ◽  
Flow Equations ◽  
Metallic Conductor ◽  
Set Up ◽  
The Stability ◽  
The Magnetic Field

Several recent investigations in geophysics and astrophysics have involved a consideration of the hydrodynamics of a fluid which is a good electrical conductor. In this paper one of the problems which seem likely to arise in such investigations is discussed. The fluid is assumed to be incompressible and in homogeneous turbulent motion, and externally imposed electric and magnetic fields are assumed to be absent. The equations governing the interaction of the electromagnetic field and the turbulent motion are set up with the same assumptions as are used to obtain the Maxwell and current flow equations for a metallic conductor. It is shown that the equation for the magnetic field is identical in form with that for the vorticity in a non-conducting fluid; immediate deductions are that lines of magnetic force move with the fluid when the conductivity is infinite, and that the small-scale components of the turbulence have the more powerful effect on the magnetic field. The first question considered is the stability of a purely hydrodynamical system to small disturbing magnetic fields, and it is shown that the magnetic energy of the disturbance will increase provided the conductivity is greater than a critical value determined by the viscosity of the fluid. The rate of growth of magnetic energy is approximately exponential, with a doubling time which can be simply related to the properties of the turbulence. General mechanical considerations suggest that a steady state is reached when the magnetic field has as much energy as is contained in the small-scale components of the turbulence. Estimates of this amount of energy and of the region of the spectrum in which it will lie are given in terms of observable properties of the turbulence.

The Small-Scale Structure of Coronal Loops

1994 ◽  
Vol 144 ◽  
pp. 189-193
Author(s):  
M. A. Berger
Keyword(s):  
Equilibrium State ◽  
Coronal Loop ◽  
Magnetic Energy ◽  
Three Dimensional ◽  
Primary Source ◽  
Small Scale ◽  
Topological Complexity ◽  
Coronal Loops ◽  
Before And After ◽  
Dissipation Model

AbstractHow do we model coronal loops which contain a rich internal structure? Coronal loops usually lie close to the equilibrium state, but equilibrium fields are generally nonlinear, three-dimensional, and contain intense current layers. Nevertheless, it is important to study highly structured loops. Small reconnection events (microflares and nanoflares) which simplify the structure may be the primary source of heat in the closed corona. The magnetic energy released during a reconnection event can be estimated if one knows the equilibrium energy before and after the event. Furthermore, structured or tangled fields dissipate wave energy more efficiently than smooth fields. Here we present a method for studying tangled fields. Lower bounds can be placed on the energy of the equilibrium field, given a measure of the topological complexity known as the crossing number. These bounds provide an estimate of the energy generated in a coronal loop due to random photospheric motions. This calculation is used to estimate the heating rate in Parker’s topological dissipation model.

Influence of the Synthesis Method on the Microstructure and the Electronic Paramagnetic Resonance in Manganite of Eu0.05Ca0.95MnO3

2011 ◽  
Vol 691 ◽  
pp. 139-144 ◽  
Author(s):  
M. Santiago T. ◽  
H. Montiel ◽  
L.E. Hernández C. ◽  
G. Álvarez ◽  
Maricela Villanueva-Ibáñez ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Single Phase ◽  
Synthesis Method ◽  
Precipitation Method ◽  
Paramagnetic Resonance ◽  
Dc Magnetic Field ◽  
X Band ◽  
Preparation Route ◽  
Co Precipitation ◽  
Electron Paramagnetic

We present a comparison between co-precipitation method and polyol mediated synthesis for obtaining sub-micrometric powders of Eu0.05Ca0.95MnO3manganite. The samples synthesized were characterized by XRD and SEM; where the compounds have a single phase with the proposed stoichiometry. Microwave absorption response in poly-crystalline Eu0.05Ca0.95MnO3samples that it is carried out by both methods, are compared. These measurements were carried out at X-band (9.4 GHz) with a dc magnetic field up to 6000 Gauss, at 300 K. Electron Paramagnetic Resonance (EPR) spectra show important differences between both samples, indicating that the processes of magnetic absorption and the temperatures of phase transition are sensitive to order/disorder local; that we associate with the preparation route.

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