Open Access

Today's audiometric methods for the diagnosis of middle ear disease are often based on a comparison of measurements with standard curves that represent the statistical range of normal hearing responses. Because of large inter-individual variances in the middle ear, especially in wideband tympanometry (WBT), specificity and quantitative evaluation are greatly restricted. A new model-based approach could transform today's predominantly qualitative hearing diganostics into a quantitative and tailored, patient-specific diagnosis, by evaluating WBT measurements with the aid of a middle-ear model. For this particular investigation, a finite element model of a human ear was used. It consisted of an acoustic ear canal and a tympanic cavity model, a middle-ear with detailed nonlinear models of the tympanic membrane and annular ligament, and a simplified inner-ear model. This model has made it possible to identify pathologies from measurements, by analyzing the parameters through senstivity studies and parameter clustering. Uncertainties due to the lack of knowledge, subjectivity in numerical implementation and model simplification are taken into account by the application of fuzzy arithmetic. The most confident parameter set can be determined by applying an inverse fuzzy method on the measurement data. The principle and the benefits of this model-based approach are illustrated by the example of a two-mass oscillator, and also by the simulation of the energy absorbance of an ear with malleus fixation, where the parameter changes that are introduced can be determined quantitatively through the system identification.

This paper presents a fully passive 13.56 -MHz RFID temperature sensor system-on-chip. Its power management unit operates over a large temperature range using a zero temperature coefficient bias source. On-chip temperature sensing is accomplished with low-voltage, low-power CMOS circuitry, and time-domain signal processing. Two readout commands have been defined to study supply noise sensitivity: 1) standard readout, where just a single set of data is transferred to the reader and 2) serial readout, where several sets of data are sent one after the other to the reader. With the standard readout command, the sensor suffers from interference from the RFID command packet and outputs interference as well, while the sensor outputs no interference with the serial readout command. Measurements show that sensor resolution with serial readout is improved by a factor of approximately 16 compared to standard readout. The chip was fabricated in a standard 0.35-μm CMOS technology and chip-on-board mounted to a tuned RFID transponder coil on an aluminum core FR4 PCB substrate. Real time wireless temperature sensing has been demonstrated with a commercial HF RFID reader. With a two-point calibration, the SoC achieves a 3σ sensing accuracy of ±0.4 ◦C from 0◦C to 125 ◦C.

The development and preservation of children’s innate creativity as they enter their professional career has grown in importance due to fundamental changes in today’s economy and society. It is therefore key to understand how teaching strategies can contribute to educational change in the early stages of schooling. Design teaching encompasses a variety of skills that can help schools shift their focus to foster children’s natural ability to “ask why” in their search for learning how to think and create. This article presents the results of an interdisciplinary workshop involving university students aiming to develop new educational approaches to foster children’s creativity through design to be implemented in the elementary school curriculum of the German federal state Baden-Württemberg. To support the workshop participants in providing a holistic concept within a compressed time period, a sustainability framework was included to further articulate their brief. The teams who were composed of chemists, computer scientists, designers, and engineers, followed the Design Thinking process to develop their proposals. A kick-off meeting presenting results of an international qualitative survey with elementary school teachers, as well as expert input during the workshop addressing the relevant topics, provided teams with key information to define their design directions. Concepts designed by each team exhibited a comprehensive solution resulting in both the abstract “education idea” and physical embodiments of the tools. Their outputs included products, interior concepts to be implemented in classrooms, exercises as well as games to support the newly developed educational models. The benefits and limitations of these concepts along with key observations of participants’ interdisciplinary collaboration are presented and discussed herein. Future work will investigate the Design knowledge of German elementary school teachers more in depth and will involve testing the new concepts in German elementary school environments.

Am Beispiel von zwei Unternehmen mit stark unterschiedlichen Strom- und Wärmebedarfswerten zeigt sich, dass aufgrund einer Amortisationszeit im günstigsten Fall von etwa 2 Jahren der Einsatz von Blockheizkraftwerken in jedem Fall wirtschaftlich lohnenswert ist. Dabei wird deutlich, dass die Auslegung des Blockheizkraftwerkes stark von den Strom- und Wärmebedarfswerten abhängt und dass der Pufferspeicher keinesfalls zu klein ausgelegt werden sollte. Das gute wirtschaftliche Ergebnis gilt bereits für den standardmäßig eingesetzten wärmegeführten Betrieb des Blockheizkraftwerkes, wobei eine intelligente stromoptimierte Steuerung mit Lastspitzenmanagement die Wirtschaftlichkeit weiter verbessert. Grundsätzlich ist darauf zu achten, dass Blockheizkraftwerke auf einen längerfristigen Betrieb ausgelegt sind. Bei jährlichen Betriebszeiten von 4.000 Stunden bis 8.000 Stunden ergibt sich ein Betrieb des Blockheizkraftwerkes über 6 bis 12 Jahre.

Der Sondermaschinenbau ist durch eine hohe Variantenvielfalt und komplexe Materialflüsse charakterisiert (Reinhart, Bredow & Pohl, 2009, S. 131). Die vorliegende Publikation stellt die im Zuge eines Praxisprojekts angewendeten Vorgehensweisen zur Materialflussoptimierung im Sondermaschinenbau vor. Dabei werden Erfahrungswerte und Hindernisse herausgearbeitet.