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Formation of regulated and novel disinfection by-products during chlorine and chlorine dioxide disinfection of surface water and groundwater
No full textThe formation of disinfection by-products (DBPs) during water disinfection is a health concern. A limited number of DBPs, such as trihalomethanes (THMs), are regulated and used as indicators of human exposure to the broader group of DBPs. However, it remains poorly understood whether the formation mechanisms and precursors of unregulated DBPs are similar to that of regulated ones. In this study, lab-scale chlorination and chlorine dioxide (ClO2) disinfection were conducted on four different source waters (two surface water and two groundwaters). DBP formation was assessed through targeted analysis of THMs via gas chromatography-mass spectrometry, novel sulfonated DBPs via supercritical fluid chromatography-mass spectrometry, and non-targeted analysis using liquid chromatography coupled to Fourier transform ion cyclotron resonance mass spectrometry (LC-FT-ICR-MS). The formation of THMs during chlorination was higher in surface waters (49–111 µg per mg dissolved organic carbon, DOC, at 48 h) than in groundwaters (21–27 µg per mg DOC) and corresponded to their higher initial specific UV-absorbance (SUVA₂₅₄) and higher humic acid fractions as determined by LC-organic carbon detection. ClO2 disinfection led to significantly lower THM levels (below the limit of detection of 0.20 µg/L) across all samples. Similarly, the formation of sulfonated DBPs was one order of magnitude lower. However, unlike THMs, sulfonated DBPs were formed to a greater extent in both groundwaters (3.0–3.6 µg per mg DOC) than in surface waters (2.0–2.2 µg per mg DOC), suggesting that sulfonated DBPs are preferentially formed from other precursors than THMs. This was further elucidated by LC-FT-ICR-MS analysis showing that the higher levels of sulfur- and nitrogen- containing dissolved organic matter in the studied groundwater samples likely contributed to the increased formation of sulfonated DBPs. Furthermore, LC-FT-ICR-MS analysis outlined that disinfection by ClO₂, while reducing halogenated DBPs, resulted in even higher levels of non-chlorinated, sulfur- and nitrogen-containing DBPs. In conclusion, strategies focused on reducing regulated THMs may be insufficient to mitigate the formation of sulfonated and other novel heteroatom-containing DBPs during drinking water treatment
Kompetenzentwicklung für KI-Tools - neue Anforderungen an die berufliche Lehrkräftebildung
No full textDie Integration von Künstlicher Intelligenz (KI) in Bildungsprozesse stellt neue Kompetenzanforderungen an Lehrende und Lernende und bietet zugleich eine konkrete Chance für die Weiterentwicklung der beruflichen Lehrkräftebildung (vgl. u. a. KMK 2024, 2021; Roppertz 2021). Der Praxisbeitrag basiert auf einem innovativen Lehransatz, der im Rahmen des von der Hamburg Open Online University (HOOU) im Jahr 2024 geförderten und am Institut für Berufliche Bildung und Digitalisierung der Technischen Universität Hamburg umgesetzten Lehrprojekts „Kom.KI – Kompetenzentwicklung für KI-Tools“ erprobt wurde. Das entwickelte Lernangebot wurde auf Basis moderierter Feedbackmethoden qualitativ evaluiert und als offene Bildungsressource implementiert. Ausführliche Informationen finden Sie über das HOOU-Lernportal unter folgendem Link: https://learn.hoou.de/course/view.php?id=733
Zielsetzung war es, die Kompetenzentwicklung von Lehramtsstudierenden und Lehrkräften im Umgang mit KI zu fördern. Im Fokus stand die Frage, wie KI-gestützte Anwendungen sinnvoll in die Lehramtsausbildung integriert und in der Praxis kompetenzorientiert weiterentwickelt werden können. Ein besonderer Schwerpunkt lag auf der Analyse der Gestaltungsmöglichkeiten und Optimierungspotenziale für den Unterricht durch generative KI-Tools wie ChatGPT, GPTschule, ChatPDF. Ein zentrales Element der Projektumsetzung war die kollaborativ angelegte Zusammenarbeit zwischen Bachelorstudierenden der Lehramtsteilstudiengänge „Gewerblich-Technische Wissenschaften“ sowie „Arbeitslehre/Technik“ und Lehrkräften aus beruflichen und allgemeinbildenden Schulen. In interdisziplinären Teams wurden praxisnahe Lösungen und methodische Ansätze für den KI-gestützten Unterricht entwickelt. Durch die Verknüpfung von Theorie und Praxis wurden neue Anlässe und interaktive Ermöglichungsräume geschaffen, um die Einsatzszenarien von KI-Tools kritisch zu reflektieren und Kompetenzentwicklungsprozesse gezielt begleiten und fördern zu können
Scenario-based planning of design method validation studies and the associated effort
No full textDesign method validation is fundamental to ensure that design methods achieve their objectives in the intended situations and are accepted in practice. Although various method validation approaches have been developed, there is still a lack of practical guidance for planning validation studies based on project characteristics. To address this, an intensity map of the validation effort is presented as the core of a scenario-based planning approach. It categorizes projects according to the novelty of the method and the state of research on the problem or the research area, enabling the required validation studies, their sequence and validation criteria to be identified. Thereby, researchers can plan validation studies and estimate the required effort situation-based, allowing for a better alignment with their individual project characteristics before starting studies
Selective mass scaling for Timoshenko beam and Mindlin plate elements based on the discrete strain gap method
No full textDeutsche Forschungsgemeinschaft (DFG
Einfluss der Schaftgeometrie einer zementfreien Primärprothese auf Beanspruchungen am proximalen Femur während der Implantation – Eine numerische Analyse
No full textThe incidence of coxarthrosis and thus the number of cementless total hip arthroplasties (THA) is increasing as a result of demographic change and the rising prevalence of obesity. However, cementless treatment is associated with an increased risk of intraoperative and postoperative periprosthetic femoral fractures (PPF), which account for 15.8 % of follow-up surgeries in Germany. The main cause of intraoperative PPF is seen in increased tangential strains on the proximal femur during stem insertion. In this research work, the displacement-controlled implantation up to the in vitro determined fracture point was simulated with the implicit time integration method in order to investigate the femoral strains in silico. Based on a quantitative computed tomography image (QCT image) of a human femur, two patient-specific, close-to-reality, linear-elastic femur models with cavities of different sizes were created (mean deviation: 0.13 mm). The comparison and validation of the simulations with two implant designs (with and without medial collar; CORAIL, Total Hip Systems, Johnson & Johnson Medical Limited, UK) against the in vitro study was based on the strains of the proximal femur and the implantation force.
In silico, collared stems resulted in increased load transfer with axial compression in the calcar-collar contact areas compared to the collarless equivalent. However, the axial compression at the proximal medial femoral surface in silico remained below the compression of -0.49 % measured in vitro. The compression of -0.21 % during stem insertion into the femur with a smaller cavity was closest to the in vitro situation. Both in vitro and in silico the proximal medial femur was initially compressed along the hoop axis during implantation. In the medial region close to the calcar, tensile hoop strains occurred only in vitro shortly before the fracture (0.69 % at the time of fracture), where they are generally considered to be the cause of the fracture. This increase was not seen in the simulations. The tangential compression in silico and in vitro is attributed to the anterior-posterior expansion of the cavity.
The simulations show that the implantation force required to reach the intended positioning of the implant and the force at the subsequent fracture position are highly dependent on the geometries used. Due to the lateral widening of the femoral cavity by up to 1.3 mm, the implantation force at the time of fracture was reduced by 55 % when collarless stems were used and by 34 % when collared stems were used. For collared stems, the implantation force prior to the calcar-collar contact was similar to the in vitro situation based on the changed geometry. As soon as calcar-collar contact was achieved, the in silico implantation force increased considerably more for collared stems than for collarless stems, and also compared to the in vitro situation.
The simulation results demonstrate that the use of a femoral geometry closer to reality with a smaller cavity is necessary in order to more realistically reproduce the axial and tangential strain distribution of an in vitro implantation in silico. By defining failure mechanisms in further studies, an implantation force closer to the in vitro situation is expected.Mit dem demografischen Wandel und der steigenden Adipositasprävalenz steigt die Coxarthroseinzidenz und damit die Anzahl zementfrei implantierter Hüfttotalendoprothesen (HTEP). Die zementfreie Versorgung ist jedoch mit einem erhöhten Risiko für intraoperative und postoperative periprothetische Femurfrakturen (PPF) verbunden, die in Deutschland 15,8 % der Folgeeingriffe begründen. Die Hauptursache für intraoperative PPF sind dabei erhöhte Dehnungen im proximalen Femur während der Schaftimplantation. Um die femoralen Beanspruchungen in silico zu untersuchen, wurde in dieser Forschungsarbeit die Implantation bis zu dem in vitro ermittelten Frakturzeitpunkt weggesteuert mit impliziter Zeitintegration simuliert. Basierend auf einem quantitativen Computertomographiebild (QCT-Bild) eines humanen Femurs wurden hierfür zwei patient:innenspezifische realitätsnahe, linear-elastische Femurmodelle mit unterschiedlich großen Kavitäten erstellt (mittlere Abweichung: 0,13 mm). Der Vergleich und die Validierung der Simulationen mit zwei Implantatdesigns (mit und ohne medialem Kalkarkragen; CORAIL, Total Hip Systems, Johnson & Johnson Medical Limited, UK) gegen die in vitro-Untersuchung erfolgte anhand der Dehnungen des proximalen Femurs und der Implantationskraft.
Im Vergleich zu dem kragenlosen Äquivalent kam es in silico bei Kragenprothesen zu einer verstärkten Lastübertragung mit einer axialen Stauchung in den Kalkar-Kragen-Kontaktbereichen. Die axialen Stauchungen an der proximalen medialen Femuroberfläche blieben in silico allerdings unterhalb der in vitro gemessenen Stauchung von -0,49 %. Die Stauchungen von -0,21 % bei der Implantation in das Femur mit kleinerer Kavität lagen der in vitro-Situation am nächsten. Sowohl in vitro als auch in silico wurde das proximale Femur während der Implantation medial entlang der Ringachse zunächst gestaucht. In dem kalkarnahen Teilbereich traten nur in vitro kurz vor der Fraktur mediale Ringdehnungen auf Zug auf (0,69 % zum Frakturzeitpunkt), die allgemein als frakturursächlich angesehen werden. In den Simulationen war dieser Anstieg nicht zu sehen. Die tangentiale Stauchung in silico und in vitro wird auf die anterior-posteriore Weitung der Kavität zurückgeführt.
Die Simulationen zeigen, dass die zur vorgesehenen Positionierung des Implantats notwendige Implantationskraft sowie die Kraft an der späteren Frakturposition stark von den verwendeten Geometrien abhängt. Durch die laterale Vergrößerung der Femurkavität um bis zu 1,3 mm reduzierte sich die Kraft zum Frakturzeitpunkt um 55 % bei der Verwendung von Implantaten ohne Kragen und um 34 % bei Implantaten mit Kragen. Bei den Kragenprothesen war die Implantationskraft vor dem Kalkar-Kragen-Kontakt durch die Geometrieveränderung ähnlich zu der in vitro-Situation. Die in silico-Implantationskraft stieg bei diesen ab dem Zeitpunkt des Kalkar-Kragen-Kontakts deutlich stärker als bei Implantaten ohne Kragen und als in vitro.
Die Simulationsergebnisse demonstrieren, dass die Verwendung einer realitätsnäheren Femurgeometrie mit kleinerer Kavität notwendig ist, um axiale und tangentiale Dehnungen während der in vitro-Implantation in silico realistischer abzubilden. Durch die Definition von Versagensmechanismen wird in weiterführenden Untersuchungen eine der in vitro-Situation nähere Implantationskraft erwartet
Annals of Scientific Society for Assembly, Handling and Industrial Robotics 2023
No full textThis open access book presents a good overview of the current research landscape of assembly, handling and industrial robotics. The objective of MHI Colloquium is the successful networking at both academic and management levels. Thereby, the colloquium focuses an academic exchange at a high level in order to distribute the obtained research results, to determine synergy effects and trends, to connect the actors in person and in conclusion, to strengthen the research field as well as the MHI community. In addition, there is the possibility to become acquainted with the organizing institute. Primary audience is formed by members of the scientific society for assembly, handling and industrial robotics (WGMHI)
Good Practice Gestaltung von Selbstlernkursen in Moodle
No full textDer Beitrag der TU Hamburg stellt Good Practice Erfahrungen aus dem Projekt "SDG Campus" vor, in dem ECTS-fähige Selbstlernkurse im MOOC-Format angeboten werden. Thematisiert werden verschiedene Optionen, eine gute Learning Experience, die Motivation der Lernenden sowie deren Aktivierung zu fördern. Der Fokus liegt dabei auf dafür vorteilhaften Moodle-Einstellungen und -Funktionen. Berücksichtigt werden u.a. Aspekte wie Kursformat/-struktur, Navigationspfade, Lernstandsverfolgung, visuelle Gestaltung/Anker, Aufgabengestaltun
Fourier neural operators to reconstruct tumor perfusion from 4D ultrasound data
No full textPerfusion imaging is becoming increasingly important for monitoring how tumors respond to therapy. It provides information about the tumor’s blood flow and vascular state. Small changes in the blood vessels happen before any anatomical changes, e.g. changes in tumor size. One approach to perfusion imaging is three-dimensional dynamic-contrast-enhanced (DCE) ultrasound. Ultrasound is widely available, low-cost and safe to use at the bedside. In 3D DCE ultrasound, a contrast agent is injected and its flow through the tumor is recorded over time. This results in 4D data consisting of the three spatial dimensions and the time evolution. This thesis investigates Fourier Neural Operators as surrogate models for partial differential equation models to solve the inverse problem of estimating tissue-specific parameters, such as blood flow, from these measurements
Design and evaluation of circular polarized antennas for UAS communication using C-V2X
No full textCellular vehicle-to-everything (C-V2X) is a technology originally developed for automotive applications. In recent years though, the C-V2X technology is considered also for Unmanned Aircraft System (UAS) communication purposes. However, the UAS scenarios significantly differ from typical road user scenarios, e.g. the communication between different UASs should be established in arbitrary directions and for larger distances, frequently exceeding 1 km. To achieve this, special-purpose antennas are required. In this paper the deployment of circular polarized (CP) slotted patch antennas for direct UAS-toUAS communication is addressed. Within the context of the German national funded project VEREDUS, the C-V2X communication technology at 5.9 GHz is deployed in order to establish a robust communication link between two different pairs of UAS types. Simulation and measurement results of the antenna matching and radiation patterns of the designed CP antennas in the UAS compartments will be shown. Last but not least, first evaluation results from actual air field tests, which depict the omnidirectional coverage characteristic of the antennas in the drones will be also provided