Diffeomorphic shape evolution coupled with a reaction-diffusion PDE on a growth potential

This paper studies a longitudinal shape transformation model in which shapes are deformed in response to an internal growth potential that evolves according to an advection reaction diffusion process. This model extends prior works that considered a static growth potential, i.e., the initial growth potential is only advected by diffeomorphisms. We focus on the mathematical study of the corresponding system of coupled PDEs describing the joint dynamics of the diffeomorphic transformation together with the growth potential on the moving domain. Specifically, we prove the uniqueness and long time existence of solutions to this system with reasonable initial and boundary conditions as well as regularization on deformation fields. In addition, we provide a few simple simulations of this model in the case of isotropic elastic materials in 2D.

Advanced Sensor For Monitoring Buoy System Marine Environments

Monitoring of marine ecosystems is essential to identify the parameters of condition. Ongoing advances utilized in senor innovation have been controlled by observing rapid and ease electronic circuits, novel sign handling techniques and imaginative advances in assembling advances. The information got from the sensors used to screen the advancement of numerical models with which to foresee the conduct of states of the water, the ocean bed and the living creatures inhabiting it. Potential field of digital signal preparing includes new methodologies for the improvement of sensor properties. In this paper proposed method are Multi-sensor buoy systems. The chance of use in beach front shallow-water marine conditions, appropriate measurements for arrangement and steadiness of the sensor framework in a moving domain like the ocean bed, and absolute independence of intensity flexibly and information recording .The buoy system has successfully performed remote monitoring of temperature and marine pressure (SBE 41CP sensor), temperature(MCP9700 sensor), atmospheric pressure (YOUNG 61302L sensor), Wind speed (DNA802sensor), and Wind direction (DNA821 sensor). Wind display and signal conditioning (meteorological translator 05603C interface). Measurement values or a decision than usually used threshold base algorithms. The watched future advancement patterns are: the scaling down of sensors and segments, the inescapable utilization of multi-sensor frameworks and the expanding significance of radio remote and self-governing sensors.

Measurement of the tilt of a moving domain wall shows precession-free dynamics in compensated ferrimagnets

One fundamental obstacle to efficient ferromagnetic spintronics is magnetic precession, which intrinsically limits the dynamics of magnetic textures. We experimentally demonstrate that this precession vanishes when the net angular momentum is compensated in domain walls driven by spin–orbit torque in a ferrimagnetic GdFeCo/Pt track. We use transverse in-plane fields to provide a robust and parameter-free measurement of the domain wall internal magnetisation angle, demonstrating that, at the angular compensation, the DW tilt is zero, and thus the magnetic precession that caused it is suppressed. Our results highlight the mechanism of faster and more efficient dynamics in materials with multiple spin lattices and vanishing net angular momentum, promising for high-speed, low-power spintronic applications.

Current vortices and magnetic fields driven by moving polar twin boundaries in ferroelastic materials

Ferroelastic twin boundaries often have properties that do not exist in bulk, such as superconductivity, polarity etc. Designing and optimizing domain walls can hence functionalize ferroelastic materials. Using atomistic simulations, we report that moving domain walls have magnetic properties even when there is no magnetic element in the material. The origin of a robust magnetic signal lies in polar vortex structures induced by moving domain walls, e.g., near the tips of needle domains and near domain wall kinks. These vortices generate displacement currents, which are the origin of magnetic moments perpendicular to the vortex plane. This phenomenon is universal for ionic crystals and holds for all ferroelastic domain boundaries containing dipolar moments. The magnetic moment depends on the speed of the domain boundary, which can reach the speed of sound under strong mechanical forcing. We estimate that the magnetic moment can reach several tens of Bohr magnetons for a collective thin film of 1000 lattice planes and movements of the vortex by the speed of sound. The predicted magnetic fields in thin slabs are much larger than those observed experimentally in SrTiO3/LaAlO3 heterostructures, which may be due to weak (accidental) forcing and slow changes of the domain patterns during their experiments. The dynamical multiferroic properties of ferroelastic domain walls may have the potential to be used to construct localized magnetic memory devices in future.

Control of Ferroelectric Domain Wall Motion using Electrodes with Limited Conductivity

This chapter addresses the experimental control of ferroelectric DW motion in thin films using electron-beam induced deposition (EBID) electrodes with limited conductivity which governs the supply of charges required for DW nucleation and propagation. The problem of a moving domain boundary, addressed in this chapter, belongs to the general class of free-boundary problems, or Stefan problems, after Josef Stefan who mathematically described ice formation and then demonstrated generality of his approach by applying the same technique to describe diffusion. In the frame of this approach the position of the boundary is determined from the transport of a physical quantity, flowing through and partially consumed at the boundary. Nowadays mathematical modelling of Stefan problems has developed into a rich field of knowledge where both analytical and numerical methods are applied to solve various important applied tasks. In this chapter, the process is described by analogy to the classical Stefan model, historically applied to the motion of phase boundaries under propagation of heat but which is here applied to precisely describe DW motion under linear electrodes and the 2D growth of a circular domain.