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Machine learning and complex network analysis of drug effects on neuronal microelectrode biosensor data
No full textBiosensors, such as microelectrode arrays that record in vitro neuronal activity, provide powerful platforms for studying neuroactive substances. This study presents a machine learning workflow to analyze drug-induced changes in neuronal biosensor data using complex network measures from graph theory. Microelectrode array recordings of neuronal networks exposed to bicuculline, a GABA
receptor antagonist known to induce hypersynchrony, demonstrated the workflow’s ability to detect and characterize pharmacological effects. The workflow integrates network-based features with synchrony, optimizing preprocessing parameters, including spike train bin sizes, segmentation window sizes, and correlation methods. It achieved high classification accuracy (AUC up to 90%) and used Shapley Additive Explanations to interpret feature importance rankings. Significant reductions in network complexity and segregation, hallmarks of epileptiform activity induced by bicuculline, were revealed. While bicuculline’s effects are well established, this framework is designed to be broadly applicable for detecting both strong and subtle network alterations induced by neuroactive compounds. The results demonstrate the potential of this methodology for advancing biosensor applications in neuropharmacology and drug discovery
A visitor experiment on astronomical x-ray optics for the “Deutsches Röntgenmuseum”
No full textThe “Deutsches Röntgen-Museum” in Remscheid (Germany) is the unique institution worldwide that researches and documents the life and work of the first Nobel Prize winner in physics, Wilhelm Conrad Röntgen, and the effects of his discovery of X-rays. As an integral part of the museum, the RöLab laboratory offers visitors the opportunity to gain practical experience in X-rays, optics and technology through own experiments. As part of a joint development project, students from Aschaffenburg University of Applied Sciences are currently designing a visitor experiment on astronomical X-ray optics for the museum´s Röntgen laboratory. An optical set-up with visible light illustrates the focusing principle of X-ray telescopes, e. g. for wide-angle optics based on the lobster-eye principle. Display boards explain the optics of various types of telescopes with accompanying text and corresponding illustrations. Modern X-ray observatories such as CHANDRA, XMM-Newton and eROSITA are presented clearly. Once implemented, the new visitor experiment inside the “Deutsches Röntgen-Museum” aims to inspire young researchers with enthusiasm for the fascinating world of X-ray optics and X-ray astronomy
Astrophysical and scientific payloads for CubeSats
No full textFor scientific and commercial applications, CubeSats enable cost-effective missions and significantly reduce the time between mission concept and launch compared to classical large satellites. Since 2000, there has been an accelerating increase in CubeSat launches, which in turn is expected to drive up the demand for dedicated optical instruments, especially in commercially relevant areas like high-resolution optics for earth observation. We present some studies and ideas of application of CubeSats mainly in the field of astronomy and astrophysics elaborated and studied at the Czech Technical University in Prague in collaboration with Aschaffenburg University of Applied Sciences. These includes single CubeSats as well as tandem CubeSat constellations. These miniature satellites can carry miniature scientific payloads for high-energy observations of both astrophysical objects as well as targets in high earth atmosphere. The examples include miniature X-ray and UV telescopes monitors and cameras, but also optical and NIR payloads. Due to the recent progress in satellite control engineering, tandem flight arrangements of mini-satellites are currently in discussion and under consideration for future space missions. CubeSat technologies offer an interesting possibility for space-born telescope payloads based on this approach. In such scenario, two small satellites will fly at a constant distance of a few meters up to 100 meters. Thereby, the front satellite will carry the telescope optics and the second satellite the detector system. The tandem flight arrangements are crucial for design of space telescopes with larger focal distances exceeding the typical sizes of small satellites
Self-supporting mid-air 3D printing of single-layer polypropylene structures: Flow rate-dependent analytical modeling and surface characterization
No full textHigh-precision deposition in material extrusion-based additive manufacturing (MEX-AM), especially in mid-air extrusion, is essential for creating microfluidic channels, integrated sensors, and tissue scaffolds with fine vascular features. However, despite advances in support-free slicing and multi-axis printing, no standardized method exists for fabricating enclosed air cavities with high shape fidelity, particularly in single-layer structures. Reliable deposition at sub-millimeter scales remains challenging, especially when printing low-stiffness polymers such as polypropylene (PP), due to delayed solidification and viscoelastic effects. This study introduces a flow-rate-dependent analytical model to predict extrusion behavior, interfacial bonding, and surface morphology in self-supporting single-layer PP structures. To validate the model, surface roughness, material distribution, and intralayer bonding were quantified using spectral analysis, cross-sectional thickness measurements, and Abbott–Firestone curve evaluation. Results show that reducing the flow rate (relative to 100% nominal flow through a 0.4 mm nozzle) to 40% improves surface roughness (Ra) to below 20
m on average across all surfaces, with the lowest Ra of 4.52 ± 0.49
m observed at a 20% flow rate on the top surfaces enclosing the cavity. The intralayer bonding between adjacent extruded lines increases up to 70%, improving deposition uniformity. Nozzle-induced smoothing effects enhance surface quality at flow rates of 60% or lower, while higher flow rates result in increased surface waviness and geometric irregularities. These findings enable the fabrication of enclosed microfluidic channels and functional cavities with well-defined surfaces and reduced mechanical stiffness, suitable for applications involving sensing, controlled deformation, or flexible system integration
Vision transformer based cut interruption detection and prediction of laser fusion cutting from monitored melt pool images
No full textIncomplete cuts during laser fusion cutting result in a closed kerf, preventing the workpiece from detaching from the sheet and resulting in rework or rejection. We demonstrate the approach of a vision transformer, used for image classification, to detect cut interruption during laser fusion cutting in steel and aluminum. With events impending an incomplete cut in steel, we attempt to predict cut interruption before they even occur. To build a data set for training, cutting experiments are carried out with a 4 kW fiber laser, forcing incomplete cuts by varying the process parameters such as laser power and feed rate. The thermal radiation from the process zone during the cutting process is captured with a size of 256 × 256 px2 at sample rates of 20 × 103 fps. The kerf is recorded with a spectral sensitivity between 400 and 700 nm, without external illumination, which enables the melt to be observed in the range of the visual spectrum. The vision transformer model, which is used for image classification, splits the image into patches, linearly embedded with an added position embedding, and fed to a standard transformer encoder. For training the model, a set of images was labeled for the respective classes of a complete, incomplete, and impending incomplete cut. With the trained model, incomplete cuts in steel and aluminum can then be recognized and impending incomplete cuts in steel can be predicted in advance
A visitor experiment on astronomical X-ray optics for the “Deutsches Röntgen Museum”
No full textThe "Deutsches Röntgen Museum” in Remscheid is the unique institution worldwide that researches and documents the life and work of the first Nobel Prize winner in physics, Wilhelm Conrad Röntgen and the effects of his discovery of X rays. As an integral part of the museum, the RöLab laboratory offers visitors the opportunity to gain practical experience in X rays, optics and technology through own experiments. As part of a joint development project, students from Aschaffenburg University of Applied Sciences are currently designing a visitor experiment on astronomical X ray optics for the museum laboratory.Poste
Infrared heating for a sustainable powder coating technology
No full textThe recent energy crisis revealed the dependence of many manufacturing companies on fossil fuels Industrial processes need to be transformed into sustainable alternatives For powder coatings, which traditionally rely on gas or oil heating systems, infrared radiation can deliver the required process heat The strong dependence of the IR absorption on the geometry of the irradiated parts as well as on the color and sort of the coating powder has to be considered before the implementation of this innovative heating The aim of the NAPUBEST project (German abbreviation for Nachhaltige Pulverbeschichtungs Technologie which means “Sustainable Powder Coating Technology”) is to get a better understanding of these correlations In our laboratory, we realized a prototype of an IR oven for test measurements The high reflectivity of silver coated reflector sheets facilitates the concentration of infrared radiation inside the oven. On the other hand, the absorption of powder coated samples in different paint colors has an impact on the heating efficiency First tests of the equipment and measurements of the angular dependence of the reflectivity of various coated samples are presented.Poste
Infrared heating for a sustainable powder coating technology
No full textIndustrial processes need to be transformed into sustainable alternatives. For powder coatings, which traditionally rely on gas or oil heating systems, infrared radiation can deliver the required process heat. The aim of the NAPUBEST project is to evaluate the possibilities of infrared radiation in the powder coating process. In our laboratory, we realized a prototype of an IR oven for test measurements
DIDACTIC INTEGRATION OF SELF-STUDY AND FACE-TO-FACE TEACHING: EXPERIENCES WITH AN ADAPTIVE LEARNING SYSTEM IN ENGINEERING EDUCATION
No full textThis paper presents a study of student perspectives on the didactic integration of digital learning elements into face-to-face university lectures and seminars. The overarching context is the use of the adaptive learning system (ALS) HASKI (short for Hochschullehre: Adaptiv, selbstgesteuert, KI-gestützt, i.e. Higher Education: Adaptive, Self-Directed, AI-Supported), which was tested in computer science teaching within a blended learning approach, more specifically in flipped classroom scenarios.
The joint project, consisting of three Bavarian universities, focuses on the exploratory integration of an AI-based ALS into higher education. The system was applied in a course for mechatronics students (2nd semester) and provided a variety of adaptive learning elements. HASKI generates individual learning paths with AI based on learning behavior and learning styles. It is designed to promote personalized, self-directed learning as support for blended learning scenarios.
The method chosen for data collection is a qualitative content analysis based on exploratory interviews with a semi-structured set of questions. Four central analysis criteria were considered: acceptance and perception of the learning elements, integration into lectures and exercise sessions, didactic coherence, and suggestions for improvement.
The results show that students prefer explanatory scripts, interactive tasks, and quiz elements that require a certain degree of reflection. In addition, the respondents are largely convinced of the integration into the seminar, as the HASKI system adequately guides them for what to prepare for. When it comes to embedding the system into lectures, especially in the form of question rotation in small groups, the feedback is ambivalent. Although the potential for in-depth learning was recognized, the low participation of fellow students was critically reflected upon.
A particular difficulty mentioned was the lack of coordination between self-study and classroom attendance. While some participants saw this as a discrepancy of coherence, others viewed the adaptive system as a balancing factor. There was a desire for a clearer time structure and more in-depth materials that go beyond mere repetition.
Overall, the findings provide initial indicators of successful aspects in the integration of adaptive systems into classroom teaching. The continuous development of a clear didactic division of roles between self-study and classroom phases is of central importance here. Further research with larger samples, if necessary, could provide more comprehensive insights
An Empirical Survey of Students’ and Professors’ Perspectives on Computer Science University Teaching
No full textThis paper presents a study which examines the pedagogical-interactional dimensions in computer science education at universities of applied sciences, focusing on the expectations and perceptions of students and professors. Data were collected using a modified version of the Learning Culture Inventory (LCI) questionnaire and analyzed both descriptively and inferentially.
The descriptive statistics reveal differences in the mean
values between the ideal and real states of educational
conditions as perceived by students and professors. Inferential
statistical analyses using t-tests identified significant differences
between the perceptions of the two groups. The effect size
Cohen’s d was also calculated to determine the strength of the
existing difference. The analyses show that there are significant
differences in many dimensions of the LCI between the
perspectives of students and professors. These differences are
often associated with high effect sizes. The results therefore
indicate that the students' expectations and perceptions deviate
(considerably) from the professors’ perspectives