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PublicationLong-term prediction of the effects of climate change on indoor climate and air quality( 2024-02-15)Limiting the negative impact of climate change on nature and humans is one of the most pressing issues of the 21st century. Meanwhile, people in modern society spend most of the day indoors. It is therefore surprising that comparatively little attention has been paid to indoor human exposure in relation to climate change. Heat action plans have now been designed in many regions to protect people from thermal stress in their private homes and in public buildings. However, in order to be able to plan effectively for the future, reliable information is required about the long-term effects of climate change on indoor air quality and climate. The Indoor Air Quality Climate Change (IAQCC) model is an expediant tool for estimating the influence of climate change on indoor air quality. The model follows a holistic approach in which building physics, emissions, chemical reactions, mold growth and exposure are combined with the fundamental parameters of temperature and humidity. The features of the model have already been presented in an earlier publication, and it is now used for the expected climatic conditions in Central Europe, taking into account various shared socioeconomic pathway (SSP) scenarios up to the year 2100. For the test house examined in this study, the concentrations of pollutants in the indoor air will continue to rise. At the same time, the risk of mold growth also increases (the mold index rose from 0 to 4 in the worst case for very sensitive material). The biggest problem, however, is protection against heat and humidity. Massive structural improvements are needed here, including insulation, ventilation, and direct sun protection. Otherwise, the occupants will be exposed to increasing thermal discomfort, which can also lead to severe heat stress indoors.
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PublicationSwitchable Heat Pipes for Eco-Friendly Battery Cooling in Electric Vehicles: A Life Cycle Assessment( 2024-02)
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PublicationReaction kinetics during early hydration of calcined phyllosilicates in model cement systems( 2024)
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PublicationBringing light into the dark - Overview of environmental impacts of carbon fiber production and potential levers for reduction( 2024)
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PublicationSensor-based characterization of construction and demolition waste at high occupancy densities using synthetic training data and deep learning( 2024)Sensor-based monitoring of construction and demolition waste (CDW) streams plays an important role in recycling (RC). Extracted knowledge about the composition of a material stream helps identifying RC paths, optimizing processing plants and form the basis for sorting. To enable economical use, it is necessary to ensure robust detection of individual objects even with high material throughput. Conventional algorithms struggle with resulting high occupancy densities and object overlap, making deep learning object detection methods more promising. In this study, different deep learning architectures for object detection (Region-based CNN/Region-based Convolutional Neural Network (Faster R-CNN), You only look once (YOLOv3), Single Shot MultiBox Detector (SSD)) are investigated with respect to their suitability for CDW characterization. A mixture of brick and sand-lime brick is considered as an exemplary waste stream. Particular attention is paid to detection performance with increasing occupancy density and particle overlap. A method for the generation of synthetic training images is presented, which avoids time-consuming manual labelling. By testing the models trained on synthetic data on real images, the success of the method is demonstrated. Requirements for synthetic training data composition, potential improvements and simplifications of different architecture approaches are discussed based on the characteristic of the detection task. In addition, the required inference time of the presented models is investigated to ensure their suitability for use under real-time conditions.
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PublicationPredicting aerosol transmission in airplanes: Benefits of a joint approach using experiments and simulation( 2024)We investigate the transmission of aerosol particles in an airplane cabin with a joint approach using experiments and simulation. Experiments were conducted in a realistic aircraft cabin with heated dummies acting as passengers. A Sheffield head with an aerosol generator was used to emulate an infected passenger and particle numbers were measured at different locations throughout the cabin to quantify the exposure of other passengers. The same setting was simulated with a computational fluid dynamics model consisting of a Lagrange continuous phase for capturing the air flow, coupled with a Lagrange suspended discrete phase to represent the aerosols. Virtual measurements were derived from the simulation and compared with the experiments. Our main results are: the experimental setup provides good measurements well suited for model validation, the simulation does correctly reproduce the fundamental mechanisms of aerosol dispersion and simulations can help to improve the understanding of aerosol transmission for example by visualizing particle distributions. Furthermore, with findings from the simulation it was possible to crucially improve the experimental setup, proving that feedback between the numerical and the hardware world is indeed beneficial.
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PublicationInvestigation on the thermal budget and flow field of a manikin and comparison with human subject in different scenarios( 2024)
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PublicationMikrobielles Leben auf Fassaden(Springer Nature, 2023-12-07)Architekten, Bauingenieure, Bausachverständige und andere Fachleute sowie Bauherren, Wissenschaftler und Masterstudenten finden in diesem Buch alle Informationen zu Fassadenalgen und -pilzen. Es gibt einen detaillierten Überblick über die Mikroorganismen, die das anfängliche Wachstum an den Außenfassaden von Gebäuden bilden und befasst sich mit den ökophysiologischen Eigenschaften, die die Rahmenbedingungen charakterisieren, unter denen diese Mikroorganismen an Fassaden auftreten können. Neben einem Bestimmungsschlüssel für die charakteristischen Anflüge an Fassaden von Mikroorganismen enthält dieses Buch eine ausführliche Beschreibung der einzelnen Organismen unter Angabe ihres ökologischen Verbreitungsgebiets. Darüber hinaus werden die verschiedenen ökologischen Parameter in kurzen Kapiteln diskutiert. Auch Maßnahmen zur Vorbeugung und Bekämpfung der Besiedelung von Fassaden mit Mikroorganismen werden thematisiert.
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PublicationEntwicklung verschiedener Baumaterialien auf der Basis der Paludikultur Rohrkolben( 2023-12-06)Ausgehend vom bereits in mehreren Gebäuden eingesetzten Typhaboard mit seinen zahlreichen umwelttechnischen und bauphysikalischen Vorteilen wurden inzwischen neue Baustoffe auf Basis von Rohrkolben entwickelt. Neben Magnesit als Bindemittel wurden mit Erfolg andere Kleber getestet, die ebenfalls nachhaltig sind und einer Kompostierung nicht im Wege stehen. Selbst unter Verwendung von Lehm können für Einsatzzwecke, die keiner besonderen Feuchtebelastung ausgesetzt sind, stabile und zugleich dämmende Platten hergestellt werden. Als Baustoff‐Neuentwicklung ist zum einen die Entwicklung eines Boards zur Aufdachdämmung zu nennen, das aufgrund einer speziellen Partikelgeometrie und ‐anordnung eine geringere Rohdichte und Wärmeleitfähigkeit besitzt. Des Weiteren wurde eine staubarme Schüttdämmung aus Rohrkolben und eine Art OSB‐Ersatz mit vergleichbaren Festigkeiten entwickelt sowie ein spezieller sehr schlanker Deckenaufbau aus Typha. Die Entwicklung eines hoch tragfähigen Holzersatzes ist ebenfalls in Arbeit.
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PublicationApplication of slags for the production of resource‐efficient paving stones( 2023-12-06)In a recent research project under the lead of the Fraunhofer Institute for Building Physics IBP, gravel and sand within a mixture of paving stones were replaced with LD converter slag and blast furnace slag for 50 wt. % and 100 wt. % to produce resource‐efficient concrete components. For this purpose, first, the dry processing of the slags including metal separation and crushing was carried out. In the next step, the particle size distributions of slags using sieve analysis were determined. Finally, the mix designs were set based on the optimum combination of different size fractions of slags. This combination was determined in a way to lead to an almost identical grading curve as that of the original formulation. Splitting tensile strengths of the obtained samples were measured after 14 days of curing under a humidity of 95%. Several paving stone specimens containing slags showed higher splitting tensile strengths than that of the reference sample. Similar results were observed for industrially produced paving stones which demonstrates the successful transfer of the laboratory mixes to the industrial plant.
