Dierk Schoen

Wilhelm Büchner Hochschule · Faculty of Engineering Sciences

In diesem wissenschaftlichen Artikel werden verschiedene Arten von Bio-Brennstoffzellen näher betrachtet, welche eine Anwendung der bioelektrochemi-schen Energiewandlung in elektrische Energie im Rahmen des Energy Harvesting darstellen. Die mikrobielle Brennstoffzel-le, eine enzymatische Brennstoffzelle und eine Blutzucker-Brennstoffzelle bilden di...

This scientific article takes a closer look at different types of biofuel cells, which represent an application of bioelectrochemical energy conversion into electrical energy in the context of energy harvesting. The microbial fuel cell, an enzymatic fuel cell and a blood sugar fuel cell form the three main groups of biofuel cells. The mode of opera...

The piezoelectric effect, which was discovered for the first time by the brothers Pierre and Jacques Curie, combines electrical with mechanical quantities and vice versa. If piezoelectric materials (e.g. quartz, turmaline) are subjected to electrical signals along certain crystal orientations, deformations along well-defined crystal orientations appe...

Robot contests are suitable for bachelor courses to gather hands-on experience in engineering diciplines such as mechanics, electronics and embedded software. After summarizing a concept of a robot contest for distance education (robot sumo) as presented in earlier publications this paper describes the implementation and first results of this conce...

This paper describes a new postgraduate master research seminar format which was designed to establish research activities for open and distance education university's degree courses. The master research seminar introduces students into professional research, publication, and presentation of their research work, based on a given field of research,...

This paper has the aim to give a generalized model for clamped-free piezoelectric n-layerd beam bending actuators for energy harvesting power generation purposes. The general approach is giving the fundamental tools for an analytical optimizing of n-layered beam bending actuators according to individually specified electrical, mechanical and materi...

Evaluation of degree courses has been established by providers of educational services and have advanced to an essential tool for optimization, steering and management of degree courses. Systematic data acquisition of the quality of courses will be a future key and obligatory for further course design and development for all providers of educationa...

This paper reviews briefly the requirements for gaseous insulation for application in GITL. Since a universal gas or gas mixture with comparable properties as SF₆ is not available, focus is on alternative gas mixtures with rather high dielectric strength and rather small environmental impact. Special focus is on N₂, N<sub>2</s...

A two-dimensional model for simulation of gas discharges along a resin insulator in SF6/N2 gas mixtures is developed by means of the Particle-in-cell and Monte Carlo (PIC-MCC) approach. The electron swarm and the following streamer developments are fully simulated, in which the elastic, exciting, ionising and attaching collisions between electrons...

This paper proposes a hybrid PIC-MCC/fluid model for streamer discharges in a needle-plane electrode system at a SF6 gas pressure of 0.1 MPa. The Particle-in-cell and Monte Carlo (PIC-MCC) scheme is used to follow electron kinetics, and calculate electron drift velocity and the rate coefficients α ( ionisation ) and η ( attachment) in the region of...

Only 7 of the sample with 20 video recorders passed the impulse test without any failure. Almost all failures observed were located in the primary part of the power supply. Typically the radio interference suppression capacitors failed and/or internal fuses were blowing. Although the damage is rather small and limited to a few components, a rather...

A two dimensional Particle-in-Cell (PIC) simulation of streamer propagation at a gas/solid interface is carried out for an inhomogeneous gap configuration. A Monte Carlo Collision module (MCC) is introduced into the usual PIC scheme to simulate the elastic, exciting, ionizing and attaching collisions between electrons and neutral gas molecules or t...

This paper deals with the numerical simulation of discharge processes in SF₆/N₂ mixtures. We introduce the particle-in-cell (PIC) method using a Monte Carlo collision module (MCC) applied to a two dimensional model of an inhomogeneous gap configuration. Calculation of the electrical field and the spatial distribution of electr...

This paper mainly deals with the calculation of the corona radius of prebreakdown phenomena of SF₆ and SF₆/N₂ gas mixtures in a pressure range from 0.1 MPa to 0.8 MPa for inhomogeneous field configuration under very fast transient voltage stress (VFT)

This paper deals with the introduction of a miniature fluxmeter or so-called field mill system for determining surface potential of insulators or metallic surfaces. The surface potential probe is specially designed to measure surface potential of charged real life cylindrical GIS spacers with and without ribs. A multiple sensing electrode allows me...

This paper deals with prebreakdown- and breakdown phenomena in SF ₆/N₂ gas mixtures, stressed with very fast transient (VFT) voltages. The investigations were performed for positive voltage, frequencies from 3 to 12 MHz, admixtures of N₂ to SF ₆ from 0% to 100% and a pressure range from 0.1 to 0.8 MPa. Ga...

This paper deals with prebreakdown and breakdown phenomena of SF6-N2-mixtures in non-uniform gaps, stressed by very fast transient voltages (VFT-voltages). in these investigations the shape of the applied voltage is similar to the voltages that can occur in gas insulated substations (GIS) due to switching operations. Because of the very fast voltag...

This paper describes the application of a double frame camera system specially developed for investigation of high speed prebreakdown phenomena in compressed gases. Design principles and performance are presented in this paper.