The accurate modelling of the eddy-current defect interaction has become an indispensable tool for the design and optimisation of eddy-current sensors. Despite the striking recent advances in modern generic numerical solvers, notably the finite element method, the application of such solvers for treating the eddy-current response problem is sub-optimal. In particular, the eddy-current response problem is characterised by a number of peculiarities such as small lift-offs and the presence of strong field gradients, which makes the use of mesh-based solvers quite delicate for a number of applications.

Variational approaches, on the other hand, involving the integral equation formalism are better suited since they are directly concerned with the field perturbation in the defect support. Their application though requires the construction of dedicated integral kernels, which intrinsically take into account the nominal piece geometry. The construction of such kernels is, however, far from being trivial. In addition, although the integral equation formulation for the harmonic problem has reached a satisfactory maturity level, their application in transient calculations is certainly much less studied.

In this talk, an overview of recent advances in variational methods for calculating the defect response will be presented, and important specialisations for the treatment of important flaw types (corrosion, pitting, stress-corrosion cracking) will be discussed. Important features such as the coupling with the measuring circuit will be evoked. Finally, different generalisation approaches for the pulsed eddy-current signature calculation will be presented. 

Recent advances in microfabrication and biotechnology have enabled the development of a wide variety of miniaturized implantable systems. Their applications range from monitoring and diagnosis to localized treatments. All these systems include, among other things, electronic components and require an energy source to power them. Although a battery can always be used, replacing it (and, more generally, the whole system) is not a routine or straightforward procedure, particularly in the case of a leadless pacemaker that is implanted directly into the patient's heart chamber. In this case, energy harvesting is a promising alternative to traditional batteries, making the systems autonomous for longer than using batteries, and enabling further miniaturization and enhanced functionality.

Biomechanical energy is particularly intense in the heart region, and has the specificity of being permanently present, unlike in other parts of the human body. Thus, converting a small fraction of available mechanical energy into electricity to power a leadless pacemaker seems an ideal solution. However, the constraints in terms of dimensions, power density, reliability and durability specific to this application present unprecedented challenges.

In this talk, we will present a summary of the state-of-the-art means currently being studied to meet these challenges. We'll then focus on the MEMS devices we've studied for this purpose: piezoelectric micro-cantilevers, piezoelectric microspirals, 3D electrostatic microtransducers and Silicon-on-Glass electrostatic MEMS. Finally, we will present the accelerated ageing method we have developed to assess the durability of piezoelectric energy harvesting devices, enabling to reproduce in just a few months what a piezoelectric device is mechanically subjected to an operating life of 20 years, corresponding to around 600 million heartbeats.

This talk will provide an overview of advanced electromagnetic sensing instruments and signal processing approaches for detecting and identifying buried explosive hazards. Subsurface explosive hazards fall into three main categories: 1, metallic (such as unexploded ordnance and metallic mines); 2. low-metal-content mines and mines constructed with intermediate conductive materials, and 3. plastic mines. Over the past two decades, significant strides have been made in developing advanced electromagnetic induction (EMI) devices and signal processing approaches. These EMI devices have been designed, built, demonstrated, and transferred to the commercial realm for the detection and identification of unexploded ordnance (UXO) along with advanced signal processing methods. Building on the success of detecting and classifying subsurface targets, research has shifted towards high-frequency EMI sensing for detecting and identifying low-metal-content targets, short and long command wires, intermediate electrical conducting targets, as well as plastic targets.

In this talk, we will first describe the basics of advanced electromagnetic induction sensing technologies for geophysical applications. This will include recent advancements in EMI instruments and software developed to detect, locate, map, and identify subsurface munitions, along with demonstrations of blind classification results at live UXO sites. The classification results will be demonstrated for targets found in both magnetic soils and marine environments. Secondly, we will outline high-frequency electromagnetic induction sensors and signal processing approaches for detecting landmines, improvised explosive devices, non-metallic projectiles (such as smart bombs), and subsurface infrastructures (such as utility wires and pipes). Finally, the integration of electromagnetic sensing technologies on remotely controlled systems, such as unmanned ground vehicles (UGVs), unmanned aerial systems (UAS) drones, and autonomous underwater vehicles (AUVs), will be highlighted.