Modeling in magnetoencephalography (MEG) and electroencephalography (EEG) requires knowledge of the vivo tissue resistivities head. The aim this paper is to examine influence resistivity changes on neuromagnetic field electric scalp potential. A high-resolution finite element method (FEM) model (452162 elements, 2-mm resolution) human head with 13 different types employed for purpose. Our main finding was that magnetic fields are sensitive vicinity source. In comparison, surface potentials...

We present the logical expressions (LE) approach that allows fast computation of three-dimensional eddy current problems, including parts in motion. The applies time-dependent to describe moving model on a fixed computational grid. study is motivated by novel nondestructive testing technique called Lorentz force (LET), which enables detection defects lying deep inside conducting material. Depending definition frame reference, we two different implementations LE referred as 1) magnet...

Magnetic sensors are widely used in automotive and industrial applications to measure linear or angular movements. Although the measurement of magnetic field vector offers opportunity estimate all mechanical degrees freedom, previous approaches could not be applied these environments. This paper presents an improved method for sensing a source's position orientation with six freedom. To solve underlying inverse magnetostatic problem, Unscented Kalman Filter combination analytical model is...

We propose a framework of nonintrusive polynomial chaos methods for transcranial magnetic stimulation (TMS) to investigate the influence uncertainty in electrical conductivity biological tissues on induced electric field. The conductivities three different tissues, namely, cerebrospinal fluid, gray matter (GM), and white matter, are modeled as uniformly distributed random variables. investigations performed simplified model cortical gyrus/sulcus structure. statistical moments calculated by...

Purpose – The purpose of this paper is to present a novel electromagnetic non-destructive evaluation technique, so called Lorentz force eddy current testing (LET). This method can be applied for the detection and reconstruction defects lying deep inside non-magnetic conducting material. Design/methodology/approach In technique described in general as well its experimental realization. Besides that, numerical simulations are performed compared data. Using output data measurements simulations,...

The problem of determining defects in structures using eddy current methods was investigated. goal this work is to demonstrate that the forces generated by currents and acting back on magnet system can be used detect object. Numerical simulations experimental investigations have been performed. This novel technique has found sensitive enough even deep an Aluminium bar moving relative field-generating system.

The present communication reports a new technique for the contactless measurement of specific electrical conductivity solid body or an electrically conducting fluid. We term “Lorentz force sigmometry” where neologism “sigmometry” is derived from Greek letter sigma, often used to denote conductivity. Lorentz sigmometry (LoFoS) based on similar principles as traditional eddy current testing but allows larger penetration depth and less sensitive variations in distance between sensor sample....

The primary aim of this paper is to present new 2-D/3-D numerical technique providing fast calculations Lorentz forces acting on a permanent magnet moving relatively solid electrically conducting object. This specific field configuration represents typical problem arising in novel non-destructive testing and evaluation known as the force eddy-current (LET). proposed technique, referred weak reaction approach (WRA) based several model simplifications, which, limits low magnetic Reynolds...

We propose a procedure to determine optimal magnet systems in the framework of nondestructive evaluation technique Lorentz force eddy-current testing (LET). The underlying optimization problem is clearly defined considering specificity scenarios. quantities involved are classified as design variables, and system scaling parameters provide high level generality. objective function absolute defect response signal (ADS) resulting from an inclusion inside object under test. Associated...

Transcranial magnetic stimulation (TMS) uses transient field to activate brain regions by inducing an electric across and current through neurons. Functional resonance imaging (fMRI) allows the measurement of activity making it a potentially useful tool in combination with TMS analyze sites within brain. typically utilizes high pulse up 8 kA at approximately 2.5 kHz induce inside sufficient for neural stimulation. Lorentz forces are created on coil increased presence external from MRI...

Modelling in magnetoencephalography (MEG) and electroencephalography (EEG) is increasingly based on the boundary element method (BEM). We quantify influence of discretization neuromagnetic neuroelectric forward inverse problem for different dipole depths, brain regions quasispherical correction. In particular we derive standards general use BEM models MEG/EEG source localization. For this purpose simulation with single current dipoles, reconstructions from somatosensory evoked potentials...

Relative movement of permanent magnet and conductor evokes forces acting on both objects (Lorentz forces). These can be used for studying material characteristics the conducting object (nondestructive testing). The paper compares various modeling techniques (transient, quasi-static, fast-quasi-static) a moving above plate using 2-D 3-D finite-element method (FEM). proposed approaches are applied to calculations force profiles which enable identify defects in conductor. comparison simulations...

Lorentz force eddy current testing is a novel nondestructive technique which can be applied preferably to the identification of internal defects in non-ferromagnetic moving conductors. This paper describes comparison this new

Lorentz force evaluation (LFE) is a technique to reconstruct defects in electrically conductive materials. The accuracy of the forward and inverse solution highly depends on applied model permanent magnet. resolution relies upon shape size Furthermore, application an existing requires analytic integral magnetic flux density. Motivated by these aspects, we propose dipoles (MDM), which magnet substituted with assembly dipoles. This approach allows modeling magnets arbitrary appropriate...

In the framework of nondestructive testing and evaluation, Lorentz force evaluation (LFE) is a method for reconstructing defects in electrically conducting laminated composites. this paper, we propose new inverse calculation strategy LFE based on stochastic optimization, differential evolution (DE) algorithm. We determined optimal control parameters DE assessed its performance simulated measured data. The results show that depth defect was estimated correctly all data sets evaluated....

Abstract The aim of this study was to investigate the impact resilience, alexithymia and subjectively perceived severity (fear death, pain intensity, helplessness) myocardial infarction (MI) on posttraumatic symptom (PTSS) after MI. Patients were assessed with Posttraumatic Diagnostic Scale (PDS), Resilience (RS-11) Toronto Alexithymia (TAS-20). Subjectively MI measured three items a 10-point Likert scale. To test our hypothesis, we applied Pearson correlations as well multiple hierarchical...

This paper provides the 3-D time-dependent analytical solution of electromagnetic fields and forces emerging if a coil or permanent magnet moves with sinusoidal velocity profile relative to conducting slab finite thickness. The results can be readily used in application scenarios related damping, eddy current braking, energy harvesting, nondestructive testing order efficiently analyze diffusion advection processes case harmonic motion. is performed for rectangular circular coils as well...

The influence of lung inhomogeneities on focal source localizations in electrocardiography (ECG) and magnetocardiography (MCG) is investigated.

Purpose The purpose of this paper is to present a 3D model deep welding dissimilar metals and show how the electron beam deflection due thermoelectric fields caused by temperature gradients in some (Seebeck effect). Design/methodology/approach A heat conduction used estimate during metals. weak coupling between analysed assembled. Additionally, influence on calculated was not taken into account. problem solved using finite element method. Findings It possible Seebeck effect relative simple...

New applications for transcranial magnetic stimulation (TMS) are rapidly being developed diagnostic and therapeutic purposes but restricted by a number of technical limitations. The ability to reliably perform TMS concurrently with functional resonance imaging (fMRI) would be valuable tool researchers. However the forces experienced coils during normal operation due large transient fields which produced, problematic. When operated within external field, such as in an fMRI scanner these can...

The paper addresses the analysis of uncertainties in framework nondestructive evaluation technique Lorentz force eddy current testing. A non-intrusive generalized polynomial chaos expansion is used order to quantify impact multiple unknown input parameters. In this context, statistics velocity and conductivity specimen as well magnetic remanence lift-off distance permanent magnet are determined experimentally modeled β-distributed uniform distributed random variables. results compared with...

We have prepared a human body phantom for experimental verification of inverse solution techniques which are applied to magnetic (and electric) measuring data. Physical models extended primary current sources were used generate these fields. Magnetic field maps closed the surface recorded by means multi-channel biomagnetic systems. Different deterministic optimization both measured and simulated data reconstruct impressed density distribution. found that all common minimum norm methods...

Source localization based on magnetoencephalographic and electroencephalographic data requires knowledge of the conductivity values head. The aim this paper is to examine influence compartment changes neuromagnetic field electric scalp potential for widely used three boundary element models. Both analysis measurement simulations with dipoles distributed in brain produced two significant results. First, we found potentials be approximately one order magnitude more sensitive than magnetic...