Fachbereich Ingenieurwissenschaften und Kommunikation
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The transport of carbon dioxide through pipelines is one of the important components of Carbon dioxide Capture and Storage (CCS) systems that are currently being developed. If high flow rates are desired a transportation in the liquid or supercritical phase is to be preferred. For technical reasons, the transport must stay in that phase, without transitioning to the gaseous state. In this paper, a numerical simulation of the stationary process of carbon dioxide transport with impurities and phase transitions is considered. We use the Homogeneous Equilibrium Model (HEM) and the GERG-2008 thermodynamic equation of state to describe the transport parameters. The algorithms used allow to solve scenarios of carbon dioxide transport in the liquid or supercritical phase, with the detection of approaching the phase transition region. Convergence of the solution algorithms is analyzed in connection with fast and abrupt changes of the equation of state and the enthalpy function in the region of phase transitions.
This work proposes a novel approach for probabilistic end-to-end all-sky imager-based nowcasting with horizons of up to 30 min using an ImageNet pre-trained deep neural network. The method involves a two-stage approach. First, a backbone model is trained to estimate the irradiance from all-sky imager (ASI) images. The model is then extended and retrained on image and parameter sequences for forecasting. An open access data set is used for training and evaluation. We investigated the impact of simultaneously considering global horizontal (GHI), direct normal (DNI), and diffuse horizontal irradiance (DHI) on training time and forecast performance as well as the effect of adding parameters describing the irradiance variability proposed in the literature. The backbone model estimates current GHI with an RMSE and MAE of 58.06 and 29.33 W m−2, respectively. When extended for forecasting, the model achieves an overall positive skill score reaching 18.6 % compared to a smart persistence forecast. Minor modifications to the deterministic backbone and forecasting models enables the architecture to output an asymmetrical probability distribution and reduces training time while leading to similar errors for the backbone models. Investigating the impact of variability parameters shows that they reduce training time but have no significant impact on the GHI forecasting performance for both deterministic and probabilistic forecasting while simultaneously forecasting GHI, DNI, and DHI reduces the forecast performance.
Integrating physical simulation data into data ecosystems challenges the compatibility and interoperability of data management tools. Semantic web technologies and relational databases mostly use other data types, such as measurement or manufacturing design data. Standardizing simulation data storage and harmonizing the data structures with other domains is still a challenge, as current standards such as the ISO standard STEP (ISO 10303 ”Standard for the Exchange of Product model data”) fail to bridge the gap between design and simulation data. This challenge requires new methods, such as ontologies, to rethink simulation results integration. This research describes a new software architecture and application methodology based on the industrial standard ”Virtual Material Modelling in Manufacturing” (VMAP). The architecture integrates large quantities of structured simulation data and their analyses into a semantic data structure. It is capable of providing data permeability from the global digital twin level to the detailed numerical values of data entries and even new key indicators in a three-step approach: It represents a file as an instance in a knowledge graph, queries the file’s metadata, and finds a semantically represented process that enables new metadata to be created and instantiated.
Accurate forecasting of solar irradiance is crucial for the integration of solar energy into the power grid, power system planning, and the operation of solar power plants. The Weather Research and Forecasting (WRF) model, with its solar radiation (WRF-Solar) extension, has been used to forecast solar irradiance in various regions worldwide. However, the application of the WRF-Solar model for global horizontal irradiance (GHI) forecasting in West Africa, specifically in Ghana, has not been studied. This study aims to evaluate the performance of the WRF-Solar model for GHI forecasting in Ghana, focusing on 3 health centers (Kologo, Kumasi and Akwatia) for the year 2021. We applied a two one-way nested domain (D1=15 km and D2=3 km) to investigate the ability of the WRF solar model to forecast GHI up to 72 hours in advance under different atmospheric conditions. The initial and lateral boundary conditions were taken from the ECMWF operational forecasts. In addition, the optical aerosol depth (AOD) data at 550 nm from the Copernicus Atmosphere Monitoring Service (CAMS) were considered. The study uses statistical metrics such as mean bias error (MBE), root mean square error (RMSE), to evaluate the performance of the WRF-Solar model with the observational data obtained from automatic weather stations in the three health centers in Ghana. The results of this study will contribute to the understanding of the capabilities and limitations of the WRF-Solar model for forecasting GHI in West Africa, particularly in Ghana, and provide valuable information for stakeholders involved in solar energy generation and grid integration towards optimized management of in the region.
Protokoll 27
(2023)
Atomic oxygen is a key species in the mesosphere and thermosphere of Venus. It peaks in the transition region between the two dominant atmospheric circulation patterns, the retrograde super-rotating zonal flow below 70 km and the subsolar to antisolar flow above 120 km altitude. However, past and current detection methods are indirect and based on measurements of other molecules in combination with photochemical models. Here, we show direct detection of atomic oxygen on the dayside as well as on the nightside of Venus by measuring its ground-state transition at 4.74 THz (63.2 µm). The atomic oxygen is concentrated at altitudes around 100 km with a maximum column density on the dayside where it is generated by photolysis of carbon dioxide and carbon monoxide. This method enables detailed investigations of the Venusian atmosphere in the region between the two atmospheric circulation patterns in support of future space missions to Venus.
A Fourier scatterometry setup is evaluated to recover the key parameters of optical phase gratings. Based on these parameters, systematic errors in the printing process of two-photon polymerization (TPP) gray-scale lithography three-dimensional printers can be compensated, namely tilt and curvature deviations. The proposed setup is significantly cheaper than a confocal microscope, which is usually used to determine calibration parameters for compensation of the TPP printing process. The grating parameters recovered this way are compared to those obtained with a confocal microscope. A clear correlation between confocal and scatterometric measurements is first shown for structures containing either tilt or curvature. The correlation is also shown for structures containing a mixture of tilt and curvature errors (squared Pearson coefficient r2 = 0.92). This compensation method is demonstrated on a TPP printer: a diffractive optical element printed with correction parameters obtained from Fourier scatterometry shows a significant reduction in noise as compared to the uncompensated system. This verifies the successful reduction of tilt and curvature errors. Further improvements of the method are proposed, which may enable the measurements to become more precise than confocal measurements in the future, since scatterometry is not affected by the diffraction limit.
A Fourier scatterometry setup is evaluated to recover the key parameters of optical phase gratings. Based on these parameters, systematic errors in the printing process of two photon polymerization (TPP) gray-scale lithography 3d printers can be compensated, namely tilt and curvature deviations. The proposed setup is significantly cheaper than a confocal microscope, which is usually used to determine calibrations parameters for compensation of the TPP printing process. The grating parameters recovered this way are compared to those obtained with a confocal microscope. A clear correlation between confocal and scatterometric measurements is first shown for structures containing either tilt or curvature. The correlation is also shown for structures containing a mixture of tilt and curvature errors (squared Pearson coefficient $r^2$ = 0.92). This new compensation method is demonstrated on a TPP printer: A diffractive optical element (DOE) printed with correction parameters obtained from Fourier scatterometry shows a significant reduction in noise as compared to the uncompensated system. This verifies the successful reduction of tilt and curvature errors. Further improvements of the method are proposed, which may enable the measurements to become more precise than confocal measurements in the future, since scatterometry is not affected by the diffraction limit.
Solar photovoltaic power output is modulated by atmospheric aerosols and clouds and thus contains valuable information on the optical properties of the atmosphere. As a ground-based data source with high spatiotemporal resolution it has great potential to complement other ground-based solar irradiance measurements as well as those of weather models and satellites, thus leading to an improved characterisation of global horizontal irradiance. In this work several algorithms are presented that can retrieve global tilted and horizontal irradiance and atmospheric optical properties from solar photovoltaic data and/or pyranometer measurements. The method is tested on data from two measurement campaigns that took place in the Allgäu region in Germany in autumn 2018 and summer 2019, and the results are compared with local pyranometer measurements as well as satellite and weather model data. Using power data measured at 1 Hz and averaged to 1 min resolution along with a non-linear photovoltaic module temperature model, global horizontal irradiance is extracted with a mean bias error compared to concurrent pyranometer measurements of 5.79 W m−2 (7.35 W m−2) under clear (cloudy) skies, averaged over the two campaigns, whereas for the retrieval using coarser 15 min power data with a linear temperature model the mean bias error is 5.88 and 41.87 W m−2 under clear and cloudy skies, respectively.
During completely overcast periods the cloud optical depth is extracted from photovoltaic power using a lookup table method based on a 1D radiative transfer simulation, and the results are compared to both satellite retrievals and data from the Consortium for Small-scale Modelling (COSMO) weather model. Potential applications of this approach for extracting cloud optical properties are discussed, as well as certain limitations, such as the representation of 3D radiative effects that occur under broken-cloud conditions. In principle this method could provide an unprecedented amount of ground-based data on both irradiance and optical properties of the atmosphere, as long as the required photovoltaic power data are available and properly pre-screened to remove unwanted artefacts in the signal. Possible solutions to this problem are discussed in the context of future work.
Normen-ABC als Uebersicht
(2023)
Dieses Video dient der Motivation, sich mit Normenthemen zu befassen. Mit dem Internationalen Normenklassifizierung System (ICS) wird begründet, warum Normenkompetenz für alle Studierenden aller Studiengänge oder Berufstätigen jeder Fachrichtung von A-Z wichtig ist. Dazu werden Nützlichkeitsbeispiele gegeben. Abschließend wird das Normen-ABC als Übersicht vorgestellt und welche Lern- und Lehrziele die einzelnen Videos haben.
Arten von Normen
(2023)
Dieses Video aus der Videoreihe „Normen-ABC“ erklärt die Herkunft und Arten von Normen. Es werden Beispiele für Normen von A bis Z gezeigt. Anhand der Planungsnorm für Projektmanagement, der ersten deutschen DIN 1 als Ausführungsnorm und der weltweit verbreiteten Prüfnorm sowie Managementnormen zur Förderung von Nachhaltigkeit wird eine Einordnung im PDCA-Zyklus gezeigt.
CE-Kennzeichnung
(2023)
Dieses Video aus der Videoreihe „Normen-ABC“ erklärt die DIN-Norm, die alle kennen sollten: DIN 5008 „Schreib- und Gestaltungsregeln für die Text- und Informationsbearbeitung“ Beuth-Verlag, Berlin: 2020. Es werden nützliche Hinweise, wie z. B. für Abschlussarbeiten, Bewerbungsschreiben oder Geschäftsbriefe gegeben.
Entstehung einer DIN-Norm
(2023)
Dieses Video aus der Videoreihe „Normen-ABC“ erklärt die Entstehung von DIN-Normen. Die Beteiligung interessierter Kreise und die Moderation durch das Deutsche Institut für Normung e.V. (DIN) wird veranschaulicht. Zur Motivation des Mitwirkens an Normen wird auf die verschiedenen Möglichkeiten dazu hingewiesen. Insbesondere junge Menschen sollen die Information erhalten, dass durch eine verkürzte Erstellung einer „DIN-SPEC“ eine technische Lösung aus Forschung und Entwicklung schnell auf den Markt zu bringen ist.
Formatnormen
(2023)
Dieses Video aus der Videoreihe „Normen-ABC“ zeigt verschiedene Formatnormen, wie Audio-, Bild- und Medienformate. Am Beispiel des weltweit einheitlichen Papierformats nach DIN EN ISO 216 wird der Aufbau durch die drei Normsätze „Halbierung und Verdoppelung“, „Ähnlichkeit“ und „Proportionalität“ erklärt.
Gesundheitsnormen
(2023)
Dieses Video aus der Videoreihe „Normen-ABC“ gibt eine Übersicht zu Gesundheitsnormen von A bis Z. Es wird veranschaulicht, wie Normen durch regionale, europäische und weltweite Vereinheitlichung Leben retten und Gesundheit schützen. Als Praxisbeispiel wird der Aufbau der Zertifizierungsnorm DIN ISO 45001 „Sicherheit und Gesundheit bei der Arbeit“ kurz erläutert.
Zertifizierungsnormen
(2023)
Dieses Video aus der Videoreihe „Normen-ABC“ gibt eine Übersicht über Zertifizierungsnormen von A-Z. Die Zertifizierung von „Produkten“, „Prozessen“, „Systemen“ und „Personen“ wird erklärt. Am Beispiel der FFP2-Masken mit richtiger CE-Kennzeichnung wird begründet, wie wichtig die Einhaltung von Normen für Gesundheit und Leben ist.
Battery lifespan estimation is essential for effective battery management systems, aiding users and manufacturers in strategic planning. However, accurately estimating battery capacity is complex, owing to diverse capacity fading phenomena tied to factors such as temperature, charge-discharge rate, and rest period duration. In this work, we present an innovative approach that integrates real-world driving behaviors into cyclic testing. Unlike conventional methods that lack rest periods and involve fixed charge-discharge rates, our approach involves 1000 unique test cycles tailored to specific objectives and applications, capturing the nuanced effects of temperature, charge-discharge rate, and rest duration on capacity fading. This yields comprehensive insights into cell-level battery degradation, unveiling growth patterns of the solid electrolyte interface (SEI) layer and lithium plating, influenced by cyclic test parameters. The results yield critical empirical relations for evaluating capacity fading under specific testing conditions.
This paper presents a novel approach to address noise, vibration, and harshness (NVH) issues in electrically assisted bicycles (e-bikes) caused by the drive unit. By investigating and optimising the structural dynamics during early product development, NVH can decisively be improved and valuable resources can be saved, emphasising its significance for enhancing riding performance. The paper offers a comprehensive analysis of the e-bike drive unit’s mechanical interactions among relevant components, culminating—to the best of our knowledge—in the development of the first high-fidelity model of an entire e-bike drive unit. The proposed model uses the principles of elastic multi body dynamics (eMBD) to elucidate the structural dynamics in dynamic-transient calculations. Comparing power spectra between measured and simulated motion variables validates the chosen model assumptions. The measurements of physical samples utilise accelerometers, contactless laser Doppler vibrometry (LDV) and various test arrangements, which are replicated in simulations and provide accessibility to measure vibrations onto rotating shafts and stationary structures. In summary, this integrated system-level approach can serve as a viable starting point for comprehending and managing the NVH behaviour of e-bikes.
Technik(en) des Designs
(2023)
Zur Geste der Medien
(2023)
Estimates of global horizontal irradiance (GHI) from reanalysis and satellite-based data are the most important information for the design and monitoring of PV systems in Africa, but their quality is unknown due to the lack of in situ measurements. In this study, we evaluate the performance of hourly GHI from state-of-the-art reanalysis and satellite-based products (ERA5, CAMS, MERRA-2, and SARAH-2) with 37 quality-controlled in situ measurements from novel meteorological networks established in Burkina Faso and Ghana under different weather conditions for the year 2020. The effects of clouds and aerosols are also considered in the analysis by using common performance measures for the main quality attributes and a new overall performance value for the joint assessment. The results show that satellite data performs better than reanalysis data under different atmospheric conditions. Nevertheless, both data sources exhibit significant bias of more than 150 W/m2 in terms of RMSE under cloudy skies compared to clear skies. The new measure of overall performance clearly shows that the hourly GHI derived from CAMS and SARAH-2 could serve as viable alternative data for assessing solar energy in the different climatic zones of West Africa.
In dieser Arbeit wird eine kompressible Semi-Lagrangesche Lattice-Boltzmann-Methode neu entwickelt und erprobt. Die Lattice-Boltzmann-Methode ist ein Verfahren zur numerischen Strömungssimulation, das auf einer Modellierung von Partikeldichten und deren Interaktion untereinander basiert. In ihrer Ursprungsform ist die Methode jedoch auf schwach kompressible Strömungen mit niedriger Machzahl beschränkt. Wesentliche Nachteile der bisherigen Versuche zur Erweiterung auf supersonische Strömungen sind entweder mangelhafte Stabilität der Verfahren, unpraktikabel große Geschwindigkeitssätze oder die Beschränktheit auf kleine Zeitschrittweiten. Als Alternative zu bisherigen Ansätzen wird in dieser Arbeit ein Semi-Lagrangescher Strömungsschritt eingesetzt. Semi-Lagrangesche Verfahren entkoppeln mittels Interpolation die Orts-, Zeit- und Geschwindigkeitsdiskretisierung der ursprünglichen Lattice-Boltzmann-Methode. Nach der Einleitung wird im zweiten und dritten Kapitel dieser Arbeit zunächst auf die Grundlagen und Prinzipien der Lattice-Boltzmann-Methode eingegangen sowie bisherige Ansätze zur Simulation kompressibler Strömungen aufgeführt. Im Anschluss wird die kompressible Semi-Lagrangesche Lattice-Boltzmann-Methode entwickelt und beschrieben. Die Erweiterung erfolgt im Wesentlichen durch die Verknüpfung der Methode mit geeigneten Gleichgewichtsfunktionen und Geschwindigkeitssätzen. Im vierten Kapitel der Arbeit werden neue Kubatur-basierte Geschwindigkeitssätze entwickelt und getestet, darunter ein D3Q45-Geschwindigkeitssatz zur Berechnung kompressibler Strömungen, der den Rechenaufwand gegenüber konventionellen Geschwindigkeitsdiskretisierungen erheblich verringert. Im fünften Kapitel der Arbeit werden zur Validierung Simulationen von eindimensionalen Stoßrohren, zweidimensionalen Riemann-Problemen und Stoß-Wirbel-Interaktionen durchgeführt. Im Anschluss zeigen Simulationen von dreidimensionalen, kompressiblen Taylor-Green-Wirbeln sowie von wandgebundenen Testfällen die Vorteile der Methode für kompressible Strömungssimulationen. Zu diesem Zweck werden die Überschallströmung um ein zweidimensionales NACA-0012-Profil und um eine dreidimensionale Kugel sowie eine supersonische Kanalströmung untersucht. Dem Simulationsteil folgt eine umfangreiche Diskussion der Semi-Lagrangeschen Lattice-Boltzmann-Methode im Vergleich zu anderen Methoden. Die Vorteile der Methode, wie vergleichsweise große Zeitschrittweiten, körperangepasste Netze und die Stabilität der Methode, werden hier herausgearbeitet.
The representation, or encoding, utilized in evolutionary algorithms has a substantial effect on their performance. Examination of the suitability of widely used representations for quality diversity optimization (QD) in robotic domains has yielded inconsistent results regarding the most appropriate encoding method. Given the domain-dependent nature of QD, additional evidence from other domains is necessary. This study compares the impact of several representations, including direct encoding, a dictionary-based representation, parametric encoding, compositional pattern producing networks, and cellular automata, on the generation of voxelized meshes in an architecture setting. The results reveal that some indirect encodings outperform direct encodings and can generate more diverse solution sets, especially when considering full phenotypic diversity. The paper introduces a multi-encoding QD approach that incorporates all evaluated representations in the same archive. Species of encodings compete on the basis of phenotypic features, leading to an approach that demonstrates similar performance to the best single-encoding QD approach. This is noteworthy, as it does not always require the contribution of the best-performing single encoding.
Text und Bild/Illustrationen
(2023)
Kreatives Schreiben
(2023)
Elektronik für Entscheider
(2023)
Dieses Buch gibt Nichtingenieuren, die sich beruflich mit Elektronik beschäftigen, die Möglichkeit, sich ein Stück auf dieses Fachgebiet zu begeben, um Aufgaben, Sprache und Vorgehensweise von Ingenieuren zu verstehen. Ziel ist es dabei nicht, nach dem Lesen dieses Buches eine elektronische Schaltung entwickeln zu können. Im Vordergrund steht vielmehr ein generelles Verständnis für die Zusammenhänge und Grundbegriffe der Elektronik. (Verlagsangaben)
Heutzutage werden alternative Mobilitätslösungen immer wichtiger. Dabei haben eBikes ihr Potential längst unter Beweis gestellt. Der zugehörige Markt ist über die letzten 10 Jahre enorm gewachsen und gleichermaßen auch die Erwartungen an das Produkt, wie bspw. eine Fahrt ohne störende Vibrationen und Geräusche zu haben. Der Motorfreilauf leistet dabei einen maßgeblichen Einfluss auf das dynamische Verhalten. In diesem Beitrag soll daher eine methodische Vorgehensweise vorgestellt werden, um mittels Versuch und Simulation den Einfluss des Motorfeilaufs auf das dynamische Verhalten der eBike Antriebseinheit zu bestimmen.
Twitchen als Kulturtechnik
(2023)
Die Maschine als Schöpferin
(2023)