TY - JOUR A1 - Manara, Jochen A1 - Hartmann, Jürgen A1 - Kerwagen, Fabian A1 - Maak, Christoph A1 - Muscio, Albert A1 - Paeth, Heiko A1 - Ebert, Hans-Peter T1 - Passive Radiative Cooling Materials with Special Focus on the Reduction of Urban Heat Island Effect: A Current Summarized Classification of Need, Approaches and Characterization Methods JF - International Journal of Thermophysics N2 - Rapidly rising global temperatures and the intensification of the urban heat island (UHI) effect necessitate new, energy-efficient solutions to mitigate heat stress in cities. Passive radiative cooling (PRC) offers a highly promising, low-energy pathway to achieve sub-ambient temperatures by reflecting incoming solar radiation while emitting long-wave infrared radiation through the atmospheric infrared window. This review summarizes key aspects of PRC and its role in reducing UHI impacts. Furthermore the fundamental physics of heat transfer and radiative heat exchange, including the materials properties such as solar reflectance and thermal emissivity which are correlated with the figures of merit, temperature drop below ambient temperature and cooling power. A comprehensive classification of current PRC materials is presented based on both structural architectures and physical effects. Additionally an overview on measurement techniques are employed to determine the performance of PRC materials, focusing on the key performance indicators. For this purpose in-field as wells as laboratory measurement techniques are introduced and opportunities in standardizing testing protocols are highlighted. Finally, future research directions are outlined, focusing on novel material development, theoretical advancements, scalable fabrication processes, and integration strategies within urban infrastructures. These innovations are important for enhancing building energy efficiency, reducing urban heat stress, and promoting sustainable urban development in the face of climate change. Y1 - 2025 U6 - https://doi.org/10.1007/s10765-025-03529-1 VL - 46 IS - 58 ER - TY - CHAP A1 - Blotevogel, Thomas A1 - Goldlücke, Jürgen A1 - Egermann, Jan A1 - Leipertz, Alfred A1 - Hartmann, Matthias A1 - Schenk, Martin A1 - Berckmüller, Martin ED - Dingel, Oliver T1 - Gemischbildungsuntersuchung in Gasmotoren mittels optischer Messverfahren, speziell in Wasserstoffmotoren T2 - Gasfahrzeuge N2 - Planar laser-induced fluorescence (PLIF) has been successfully used for the investigation of the mixture formation process in hydrogen engines for passenger cars. Detailed information has been obtained about process development (qualitative measurement) and on fuel/air-ratio (quantitative measurement) inside the combustion chamber. These results can be used for further optimization of mixture formation and combustion process concerning emissions and fuel consumption. The measurement technique used is not only limited to hydrogen or to passenger car engines, but can also be applied to other fuel gases like natural gas or to other engine sizes like bus engines. The main topic of this paper is the experimental verification of the procedure which was executed by simultaneous PLIF and Raman scattering measurements. By Raman scattering the fuel/air-ratio can directly be determined from direct concentration measurements of the different gas species. The fuel/air-ratios determined by PLIF and Raman measurements are in good agreement indicating that a quantitative fuel/air-ratio measurement during the mixture formation process of gas and hydrogen engines is possible by PLIF. This fact is also confirmed by other measurements, e.g., global fuel/air-ratio calculated from measured intake air and fuel gas flow. KW - Wasserstoff Gasmotor Laser Optische Messtechnik Y1 - 2004 SN - 3816924395 SP - 205 EP - 229 PB - expert verlag CY - Renningen ER - TY - JOUR A1 - Strasser, Claire A1 - Moukhina, Elena A1 - Hartmann, Jürgen T1 - Time–Temperature-Transformation (TTT) Cure Diagram of an Epoxy–Amine System JF - Macromolecular Theory and Simulations Y1 - 2024 UR - https://doi.org/10.1002/mats.202400039 VL - 33 IS - 6 SP - 2400039 ER -