English
Related papers

Related papers: Characterising buried objects in metal detection

200 papers

Realistic applications in metal detection involve multiple inhomogeneous conducting permeable objects and the aim of this paper is to characterise such objects by polarizability tensors. We show that, for the eddy current model, the leading…

Analysis of PDEs · Mathematics 2018-09-25 P. D. Ledger , W. R. B. Lionheart , A. A. S. Amad

We present a new complete asymptotic expansion for the low frequency time-harmonic magnetic field perturbation caused by the presence of a conducting (permeable) object as its size tends to zero for the eddy current regime of Maxwell's…

Analysis of PDEs · Mathematics 2018-05-23 P. D. Ledger , W. R. B. Lionheart

Being able to characterise objects at low frequencies, but above the limiting frequency of the eddy current approximation of the Maxwell system, is important for improving current metal detection technologies. Importantly, the upper…

Analysis of PDEs · Mathematics 2022-09-28 P. D. Ledger , W. R. B. Lionheart

We present new alternative complete asymptotic expansions for the time harmonic low--frequency magnetic field perturbation caused by the presence of a conducting permeable object as its size tends to zero for the eddy current approximation…

Analysis of PDEs · Mathematics 2022-07-11 P. D. Ledger , W. R. B. Lionheart

The measurement of time-harmonic perturbed field data, at a range of frequencies, is beneficial for practical metal detection where the goal is to locate and identify hidden targets. In particular, these benefits are realised when frequency…

Analysis of PDEs · Mathematics 2020-01-08 P. D. Ledger , W. R. B. Lionheart

The inductive response of an object to an oscillating magnetic field reveals information about its electrical conductivity and magnetic permeability. Here we introduce a technique that uses measurements of the angular, frequency and spatial…

Applied Physics · Physics 2021-11-24 R. Gartman , W. Chalupczak

Our interest lies in the identification of hidden conducting permeable objects from measurements of the perturbed magnetic field in metal detection taken over range of low frequencies. The magnetic polarizability tensor (MPT) provides a…

Numerical Analysis · Mathematics 2020-01-22 B. A. Wilson , P. D. Ledger

The early detection of terrorist threats, such as guns and knives, through improved metal detection, has the potential to reduce the number of attacks and improve public safety and security. To achieve this, there is considerable potential…

Cryptography and Security · Computer Science 2020-12-21 P. D. Ledger , B. A. Wilson , A. A. S. Amad , W. R. B. Lionheart

The three electromagnetic properties appearing in Maxwell's equations are dielectric permittivity, electrical conductivity and magnetic permeability. The study of point diffractors in a homogeneous, isotropic, linear medium suggests the use…

Geophysics · Physics 2013-06-10 Albane Saintenoy , A. Tarantola

High-dimensional wireless power transfer (WPT) systems have received increasing attention for charging mobile devices. With the receivers have higher spatial freedom, the systems are more susceptible to the metal objects in the…

Signal Processing · Electrical Eng. & Systems 2019-07-03 Zixi Liu , Qi Zhu , Mei Su

The aim of this paper is provide new insights into the properties of the rank 2 polarizability tensor $\check{\check{\mathcal M}}$ proposed in (P.D. Ledger and W.R.B. Lionheart Characterising the shape and material properties of hidden…

Optics · Physics 2018-07-04 P. D. Ledger , W. R. B. Lionheart

We derive synthetic electrical conductivity, seismic velocity, and density distributions from the results of martian mantle convection models affected by basin-forming meteorite impacts. The electrical conductivity features an intermediate…

Earth and Planetary Astrophysics · Physics 2021-02-09 Thomas Ruedas , Doris Breuer

The early detection of terrorist threat objects, such as guns and knives, through improved metal detection, has the potential to reduce the number of attacks and improve public safety and security. To achieve this, there is considerable…

Machine Learning · Computer Science 2021-10-14 B. A. Wilson , P. D. Ledger , W. R. B. Lionheart

Understanding the electronic transport properties of iron under high temperatures and pressures is essential for constraining geophysical processes. The difficulty of reliably measuring these properties under Earth-core conditions calls for…

Materials Science · Physics 2023-03-15 Kushal Ramakrishna , Mani Lokamani , Andrew Baczewski , Jan Vorberger , Attila Cangi

The lack of reliable methods for identifying descriptors - the sets of parameters capturing the underlying mechanisms of a materials property - is one of the key factors hindering efficient materials development. Here, we propose a…

Materials Science · Physics 2018-08-15 Runhai Ouyang , Stefano Curtarolo , Emre Ahmetcik , Matthias Scheffler , Luca M. Ghiringhelli

We discover many new crystalline solid materials with fast single crystal Li ion conductivity at room temperature, discovered through density functional theory simulations guided by machine learning-based methods. The discovery of new solid…

Materials Science · Physics 2019-04-22 Austin D. Sendek , Ekin D. Cubuk , Evan R. Antoniuk , Gowoon Cheon , Yi Cui , Evan J. Reed

Precipitation and dissolution are prime processes in carbonate rocks and being able to monitor them is of major importance for aquifer and reservoir exploitation or environmental studies. Electrical conductivity is a physical property…

Geophysics · Physics 2020-09-01 Flore Rembert , Damien Jougnot , Luis Guarracino

Electrical conductivity (EC) is one of the important physical properties of minerals and rocks that can be used to characterize the composition and structure of the deep interior of the Earth.Theoretical studies have predicted that the…

Geophysics · Physics 2025-06-10 Mako Inada , Yoshiyuki Okuda , Kenta Oka , Hideharu Kuwahara , Steeve Gréaux , Kei Hirose

Purpose: Magnetic polarizability tensors (MPTs) provide an economical characterisation of conducting magnetic metallic objects and their spectral signature can aid in the solution of metal detection inverse problems, such as scrap metal…

Numerical Analysis · Mathematics 2024-05-01 James Elgy , Paul D. Ledger

We investigate the conductivity in layered metals in magnetic field in the weakly incoherent limit, when the interlayer transfer integral is smaller than the Landau level broadening due to the impurity potential, but the interlayer electron…

Mesoscale and Nanoscale Physics · Physics 2011-11-11 Pavel D. Grigoriev
‹ Prev 1 2 3 10 Next ›