Publikationsserver der Ostbayerischen Technischen Hochschule Regensburg
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Effect of Carbon Content on the Phase Composition, Microstructure and Mechanical Properties of the TiC Layer Formed in Hot-Pressed Titanium-Steel Composites
No full textDuring the hot pressing of pure titanium and different carbon steels in a temperature range of ϑ = 950–1050 °C, a compound layer up to dL≈10 μm thick is formed at the titanium–steel interface. With a higher carbon content of the used steel, the layer thickness increases. The carbon concentration within the layer is in the range of stoichiometry for TiC. Apart from TiC, no other phases can be detected by X-ray diffraction (XRD) measurements inside the formed layer. The calculation of the activation energy for the TiC layer formation is Q = 126.5–136.7 kJ mol−1 and is independent of the carbon content of the steel. The resulting microstructure has a grain size gradient, wherein the mechanical properties, such as hardness and Young‘s modulus, are almost constant. Statistical analysis using Response Surface Methodology (RSM) indicates that the carbon content of the steel has the most significant influence on layer thickness, followed by annealing temperature and annealing time. By selecting the appropriate carbon steel and the subsequent removal of the steel, it is possible to produce targeted TiC layers on titanium substrates, which holds enormous potential for this material in wear-intensive applications
Paradigmenwechsel? Karsten Weber über KI in den Geistes- und Sozialwissenschaften
No full textIn dieser Folge begrüßen wir ein weiteres Mal Karsten Weber von der OTH Regensburg zu Gast, Professor für Technikfolgenabschätzung und Technikbewertung an der Fakultät für Informatik und Mathematik. Gemeinsam mit unserem Moderator Peter Kann spricht er über Herausforderungen und Potenziale, die das verstärkte Aufkommen von Künstlicher Intelligenz in den Geistes- und Sozialwissenschaften hervorruft, sowie über die damit verbundenen philosophischen Fragen nach Bewusstsein, Denken und Emotionen von Maschinen. Erfahren Sie außerdem, warum Grenzen zwischen quantitativen und qualitativen Forschungsarbeiten zunehmend schwinden und wie eine enge interdisziplinäre Zusammenarbeit neue Impulse zur Bewältigung des Spannungsfeldes globaler Wettbewerbsfähigkeit und der Regulierung von KI geben kann
Fabrication and Dielectric Validation of an Arm Phantom for Electromyostimulation
No full textElectromyostimulation (EMS) is an up-and-coming training method that demands further fundamental research regarding its safety and efficacy. To investigate the influence of different stimulation parameters, electrode positions and electrode sizes on the resulting voltage in the tissue, a tissue mimicking phantom is needed. Therefore, this study describes the fabrication of a hydrogel arm phantom for EMS applications with the tissue layers of skin, fat, blood and muscle. The phantom was dielectrically validated in the frequency range of 20 Hz to 100 Hz. We also conducted electromyography (EMG) recordings during EMS on the phantom and compared them with the same measurements on a human arm. The phantom reproduces the dielectric properties of the tissues with deviations ranging from 0.8% to more than 100%. Although we found it difficult to find a compromise between mimicking the permittivity and electrical conductivity at the same time, the EMS-EMG measurements showed similar waveforms (1.9-9.5% deviation) in the phantom and human. Our research contributes to the field of dielectric tissue phantoms, as it proposes a multilayer arm phantom for EMS applications. Consequently, the phantom can be used for initial EMS investigations, but future research should focus on further improving the dielectric properties
Report of RILEM TC 281-CCC: A critical review of the standardised testing methods to determine carbonation resistance of concrete
No full textThe chemical reaction between CO2 and a blended Portland cement concrete, referred to as carbonation, can lead to reduced performance, particularly when concrete is exposed to elevated levels of CO2 (i.e., accelerated carbonation conditions). When slight changes in concrete mix designs or testing conditions are adopted, conflicting carbonation results are often reported. The RILEM TC 281-CCC ‘Carbonation of Concrete with Supplementary Cementitious Materials’ has conducted a critical analysis of the standardised testing methodologies that are currently applied to determine carbonation resistance of concrete in different regions. There are at least 17 different standards or recommendations being actively used for this purpose, with significant differences in sample curing, pre-conditioning, carbonation exposure conditions, and methods used for determination of carbonation depth after exposure. These differences strongly influence the carbonation depths recorded and the carbonation coefficient values calculated. Considering the importance of accurately determining carbonation potential of concrete, not just for predicting their durability performance, but also for determining the amount of CO2 that concrete can re-absorb during or after its service life, it is imperative to recognise the applicability and limitations of the results obtained from different tests. This will enable researchers and practitioners to adopt the most appropriate testing methodologies to evaluate carbonation resistance, depending on the purpose of the conclusions derived from such testing (e. g. materials selection, service life prediction, CO2 capture potential)
Uncertainty, politics, and crises: The case for cash
No full textWe analyze the repercussions of different kinds of uncertainty on cash demand, including uncertainty of cashless infrastructures, confidence crises of the financial system, natural disasters, political uncertainties, and inflationary crises. Based on a comprehensive literature survey and complemented by case studies, we derive a classification scheme how cash holdings typically evolved in each of these types of uncertainty over the past 30 years by separating between demand for domestic and international cash as well as between transaction and store of value balances. Hereby, we focus on the stabilizing macroeconomic properties of cash and recommendguidelines for cash supply by central banks and the banking system. Finally, we exemplify ouranalysis with five case studies from the developing world, namely Venezuela, Zimbabwe, Afghanistan, Iraq, and Libya
Towards improving data interoperability for the reconstruction of existing buildings
No full textDigital representations of buildings are the supporting structures of various use-cases in the emerging field of data-driven decision making. From large scale applications in the context of city planning to the detailed evaluation of critical infrastructure they enable specialists to observe problems, interpret relationships, test solutions virtually and apply them in the real world. This is only feasible if the individual underlying digital model meets the requirements imposed by the analysis at hand.
In practice, especially models of existing buildings are not easy to come by as the information describing the existing structure is often scattered across multiple different data sources in various formats. Previous research efforts have outlined methodologies which leverage machine learning, computer vision and subsequent semantic enrichment in order to achieve the (re)construction of such building models. However, these methods are generally not integrated with each other, nor do they consider being able to interface with a shared repository of building related data.
In this paper we present a methodology which focuses on establishing a common context for all building related data by utilizing the Industry Foundation Classes (IFC) schema. In particular we focus on utilizing readily available geometric and semantic data originating from geographic information systems as a basis, subsequently referencing additional data sources in their corresponding context and finally outlining interfaces with downstream enrichment processes in both directions. Through incorporating contextualized (IFC) data into the early stages of the remodeling workflow, we outline an end-to-end process from the initial component-based data-acquisition to the as-built building information model. In establishing a standardized foundation for data exchange and collaboration it enables all stakeholders to work more seamlessly across different stages of the remodeling project
Baugrundverbesserung mittels Kunstharzsäulen zur Nachgründung sich setzender Gebäude
No full textIm Beitrag werden neben der Herstellung und Wirkungsweise auch die Ergebnisse von Versuchen im Maßstab 1:1 an neuartigen Kunstharzsäulen vorgestellt, die als ein minimalinvasives Injektionsverfahren speziell zur Nachgründung und Stabilisierung bestehender Bauwerke auf setzungsempfindlichen Untergrund mit geringer Tragfähigkeit entwickelt wurde
FMS-Berichte Wintersemester 2023/24
No full textDieser Bericht entstand ursprünglich auf Initiative der Studierenden des damals neuen Masterstudiengangs „Elektro- und Informationstechnik (MEI)“ an der OTH Regensburg, die an der Pflichtlehrveranstaltung „Forschungsmethoden und Seminar (FMS)“ im Wintersemester 2020/21 teilnahmen.
Diese Lehrveranstaltung hat das Ziel, systematisch an das wissenschaftliche Arbeiten, speziell die Wissenschaftskommunikation, heranzuführen. Daher ist im Laufe der Veranstaltung geeignete Literatur zu einem individuellen Thema zu recherchieren, sind Veröffentlichungen auf ihre Relevanz hin zu beurteilen und letztendlich gilt es eine eigene Ausarbeitung basierend auf der Literaturrecherche zu erstellen und diese in einem Vortrag zu präsentieren.
Parallel dazu wird im Theorieteil die entsprechende Hinführung zu den verschiedenen Elementen der Wissenschaftskommunikation vermittelt:
• Bedeutung der Wissenschaftskommunikation für die Arbeit der Ingenieure in Forschung und Entwicklung
• Literaturrecherche, Suchmaschinen, Sichtung und Analyse vorhandener Publikationen, Bewertung der Qualität aufgefundener Fachliteratur, Auswahl geeigneter Materialien für die eigene Arbeit
• Aufbereitung und Darstellung der recherchierten technischer Inhalte in Form einer seitenanzahlbegrenzten wissenschaftlichen Ausarbeitung
• Einhalten formaler Randbedingungen bzgl. Strukturierung, einschl. Bildnachweise und Zitationsstile
• Peer-review-Prozess bei wertschätzender Beurteilung der Leistung anderer
• Publikumsangepasstes Aufbereiten komplexer fachlicher Inhalte mit hochschulöffentlicher Präsentation der Ergebnisse
• Führen mündlicher wissenschaftlicher Diskurse
Die präsentierten Themen beruhen nicht auf eigener Forschungstätigkeit, sondern sind als einführende Reviewartikel zum jeweiligen vorgegebenen technischen oder gesellschaftspolitischen Forschungsthema zu verstehen
