Parametric amplification and stochastic resonance in bio-inspired hair flow sensors

Inspired by crickets and its perception for flow phenomena, artificial hair flow sensors have been developed successfully in our group. The realization of array structures and improvement of fabrication methodologies have led to better performance, making it possible to detect and measure flow velocities in the range of sub-mm/s. To improve the performance of these artificial hair flow sensors even further, we will make use of non-linear effects. In nature a wide range of such effects exist (filtering, parametric amplification, etc.) and can give a rise\ud in sensitivity, dynamic range and selectivity. Here, we propose to use parametric amplification and stochastic resonance to improve our flow sensor performance

Simulation studies of parametric amplification in bio-inspired flow sensors

In this paper the effect of parametric amplification in MEMS-based air-flow hairsensors is studied. With an AC-voltage controlled torsional stiffness the rotation of the hair can be influenced. With the appropriate amplitude, phase and frequency, the rotation of the torsional hair system is increased with respect to the case without parametric amplification. Therefore, parametric amplification is identified as a method to improve the performance of MEMS-based hair air flow sensors

Map estimation of air-flow dipole source positions using array signal processing

In nature, fish have the ability to form flow-based maps to assist localizing predator or prey using the lateral-line system. Yet it is not fully understood what techniques are used by fish to draw these flow maps. Biologists try to figure out fish techniques by investigating different hypotheses [1]. Inspired by the lateral line of fish, we propose in this paper model based array signal processing techniques used to visualize the air-flow maps. The results show an ability to visualize the flow field generated by a dipole source using lateral-line system

3D printing of functional structures

The technology colloquial known as ‘3D printing’ has developed in such diversity in printing technologies and application fields that meanwhile it seems anything is possible. However, clearly the ideal 3D Printer, with high resolution, multi-material capability, fast printing, etc. is yet to be developed. Nevertheless, one can al- ready start to wonder what possibilities for electrical engineering applications will become available in the near future. Here I try to give a brief and balanced overview of current developments and a few examples of the first small steps towards 3D printed transducers

On the accuracy of the finite difference method for applications in beam propagating techniques

In this paper it is shown that the inaccuracy in the beam propagation method based on the finite difference scheme, introduced by the use of the slowly varying envelope approximation, can be overcome in an effective way. By the introduction of a perturbation expansion the accuracy can be improved as much as wanted, often nearly without any increase of the computation time. An error analysis is given and the method is illustrated by an example

Efficient interface conditions for the finite difference beam propagation method

It is shown that by adapting the refractive indexes in the vicinity of interfaces, the 2-D beam propagation method based on the finite-difference (FDBPM) scheme can be made much more effective. This holds especially for TM modes propagating in structures with high-index contrasts, such as surface polaritons. A short discussion is given on the applicability of the FDBP

New formulation of the beam propagation method based on the slowly varying envelope approximation

We combine the theoretical results of some recent publications on the beam propagation method based on the finite difference method (FDBPM) and the slowly varying envelope approximation (SVEA). The use of the SVEA leads to a considerable reduction of the computation time but introduces a fundamental error in the phase velocity of a given mode and also to an error due to the finite step size along the propagation direction. A new, effective scheme is given, which results in a considerable reduction of these errors, without much increase of the computational effort. An error analysis and a few results of applications are given

Multifunctional Tool for Expanding AFM-Based Applications

A multifunctional tool which expands the application field of atomic force microscope-based surface modification is presented. The AFM-probe can be used for surface modification and in-situ characterization at the same time, due to a special configuration with two cantilevers. Various applications from different fields are presented, which were carried out with one and the same tool: in-situ characterization of wear generated with and without local lubrication (tribology), fountain-pen lithography in which material is deposited or removed (physical chemistry), and electrochemical metal deposition (electrochemistry)

Low-cost multimode waveguide couplers for multimode fiber-based local area networks

Novel, ultra-compact multimode fiber-matched integrated optical 1×2, 1×3 and 2×2 couplers with low excess losses and large tolerances have been designed and simulated using a fully three-dimensional beam propagation metho

Three dimensional adhesion model for arbitrary rough surfaces

We present a 3D adhesion model based on the JKR theory applied locally for all contacting asperity couple and the calculations account the van der Waals interaction beside the externally applied force. Thus, equilibrium of the system is determined by an extremum in the free total energy and subsequently the contact and the adhesion parameters are computed for that particular position. The model estimates the adhesion of contacting arbitrary rough surfaces taking into account that asperities deform according to one of the three deformation regimes (elastic, elasto-plastic and plastic). The deformation of the contacting asperities is determined by the material properties, the asperity characteristics as well as the surface topography. Results show that even outside the bonding regime the specific bonding energy is still high enough to cause adhesive problems for microstructures