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Krisen und Auswege : Ringvorlesung im Wintersemester 2022/2023 an der TH Aschaffenburg
No full textKrisen gab es schon immer. Aktuell hat sich jedoch ein ganzes Spektrum an Krisen entfaltet – es gibt politische und militärische Krisen, es brechen Energiemärke und Lieferketten weg, wir sehen ganze Branchen gefährdet, auch die Gesundheit macht uns Sorgen, vom Klimawandel ganz zu schweigen. In den Veranstaltungen der Ringvorlesung „Krisen und Auswege“, die im Wintersemester 2022/2023 stattfand, wurden Phänomene, Konzepte und Lösungen aus vielfältiger Perspektive erschlossen und damit die Komplexität des Gegenstands aufgezeigt. Herausforderungen für Unternehmen und Privatpersonen wurden identifiziert sowie der Einfluss auf technologische und organisatorische Entwicklungswege dargelegt.
In dieser Publikation wurden die einzelnen Vorträge der Ringvorlesung von den Autorinnen zusammengefasst
Towards Pressure Sensors Based on Polymer Planar Bragg Gratings
No full textWhile Bragg grating-based optical devices have shown promising performances for pressure sensing applications, their sensitivity, especially in the low-pressure regime, is unsatisfying and needs to be optimized by elaborate designs, such as cantilevers or other extrinsic mechanical transducers. This contribution demonstrates and discusses a novel concept for optical pressure sensors based on polymer planar Bragg gratings. Waveguide and Bragg grating are fabricated underneath the surface of a temperature-stable and humidity-insensitive cyclic olefin copolymer substrate by means of a femtosecond laser. Based on the employed direct-writing procedure, in combination with adaptive, in-situ beam shaping with a spatial light modulator, writing depth, i.e., location of the photonic structures within the substrate, as well as Bragg grating periodicity and positioning can be deliberately chosen. Afterwards, the polymer substrate is post-processed with a high-precision micro mill, so a diaphragm comprising the integrated photonic structures is generated. The resulting diaphragm exhibits a thickness of 300 µm and a diameter of 10 mm. Finally, the optical sensor is packaged and sealed to form an air-filled gas pocket underneath the diaphragm. Deformations of the diaphragm by external pressure changes translate to strain variations along the waveguide axis and thus perturb the Bragg grating period. This leads to changes in the grating’s wavelength of main reflection, which can be evaluated in order to quantify the relative external pressure. With this straightforward optical sensor concept, pressure sensitivities up to 39 pm kPa-1, within relative pressures ranges from 78 kPa to 372 kPa, are achieved
Intermittierende Auskultation – eine alte Technik neu erlernen
No full textEinschlägige Richtlinien empfehlen die intermittierende Auskultation als Überwachungsmethode erster Wahl bei Nicht-Risiko-Schwangeren. Hierfür müssen bestimmte Rahmenfaktoren gegeben sein sowie die Fachexpertise der betreuenden Hebamme. Diese lässt sich durch entsprechende Fortbildung erlangen
Analysis of quantile graphs in EGC data from elderly and young individuals using machine learning and deep learning
No full textHeart disease, also known as cardiovascular disease, encompasses a variety of heart conditions that can result in sudden death for many people. Examples include high blood pressure, ischaemia, irregular heartbeats and pericardial effusion. Electrocardiogram (ECG) signal analysis is frequently used to diagnose heart diseases, providing crucial information on how the heart functions. To analyse ECG signals, quantile graphs (QGs) is a method that maps a time series into a network based on the time-series fluctuation proprieties. Here, we demonstrate that the QG methodology can differentiate younger and older patients. Furthermore, we construct networks from the QG method and use machine-learning algorithms to perform the automatic diagnosis, obtaining high accuracy. Indeed, we verify that this method can automatically detect changes in the ECG of elderly and young subjects, with the highest classification performance for the adjacency matrix with a mean area under the receiver operating characteristic curve close to one. The findings reported here confirm the QG method’s utility in deciphering intricate, nonlinear signals like those produced by patient ECGs. Furthermore, we find a more significant, more connected and lower distribution of information networks associated with the networks from ECG data of the elderly compared with younger subjects. Finally, this methodology can be applied to other ECG data related to other diseases, such as ischaemia
UV picosecond laser drilling of ABF film material for printed circuit boards using laser burst mode and beam shaping
No full textWe report on an experimental study of laser microvia percussion drilling of Ajinomoto build-up film (ABF) material using an ultrashort pulsed laser in the ultraviolet region. In order to optimize the drilling quality in terms of the fabricated taper and microvia diameter, the
MHz burst mode is used in combination with both a Gaussian and a top-hat laser intensity distribution. To evaluate the influence of the top-hat beam shape on defocusing, microvias were drilled at different z-positions in the range of 200 μm evenly distributed around the focal plane. The drilling quality was evaluated by laser scanning microscopy and metallography. When using a top-hat beam shape, a reduced taper of down to 26.8 % on average is achieved compared to a Gaussian beam. For the application of 3 intra-burst pulses, we find an improvement of the taper by 11.6% compared to the single pulse mode due to the increasing heat accumulation. Using a top-hat beam shape in combination with the MHz burst mode, an 18.2 % reduction in laser drilling time for a microvia with a similar taper is remarkable, demonstrating the high potential for scaling throughput in electronics manufacturing
Multi-Bessel Beams Generated by an Axicon and a Spatial Light Modulator for Drilling Applications
No full textWe report on an optical setup to generate multi-Bessel beam profiles combining a refractive axicon and a spatial light modulator. Based on their particular beam profile, Bessel beams offer advantageous properties for micro drilling processes and internal volume processing, especially for transparent materials. In addition, the laser power of industrial, ultrashort pulsed lasers has increased significantly over the last few years, offering the possibility for highly efficient processes using multi-spot profiles. Our optical concept combines the dynamic possibilities of beam splitting using a spatial light modulator with the benefits of Bessel beams, which facilitates multi-Bessel beam processing. Beside the simulation and experimental evaluation of the generated multi-Bessel beams, we exemplify the applicability of the developed module for the perforation of thin metal foils by micro drilling
An image encoding method for recording projection information of two-dimensional projections
No full textUnsichtbares erkunden - Experimente im Museumslabor RöLab des Deutschen Röntgen-Museums
No full textDas RöLab versteht sich als ein überregionales, außerschulisches Bildungsangebot, das Begeisterung für Natur- und Ingenieurwissenschaften, Medizin und Medizintechnik an unterschiedliche Zielgruppen vermittelt und damit einen Beitrag zur Allgemeinbildung und MINT-Förderung leistet. Das didaktische Konzept nimmt den „Hands-on-Science“ Gedanken stringent auf, weckt den Forschergeist und ermöglicht es den Lernenden, Unsichtbares zu erkunden