TY - CHAP A1 - Schwager, Christian A1 - Angele, Florian A1 - Nouri, Bijan A1 - Schwarzbözl, Peter A1 - Teixeira Boura, Cristiano José A1 - Herrmann, Ulf T1 - Impact of DNI forecast quality on performance prediction for a commercial scale solar tower: Application of nowcasting DNI maps to dynamic solar tower simulation T2 - SolarPACES 2022 conference proceedings N2 - Concerning current efforts to improve operational efficiency and to lower overall costs of concentrating solar power (CSP) plants with prediction-based algorithms, this study investigates the quality and uncertainty of nowcasting data regarding the implications for process predictions. DNI (direct normal irradiation) maps from an all-sky imager-based nowcasting system are applied to a dynamic prediction model coupled with ray tracing. The results underline the need for high-resolution DNI maps in order to predict net yield and receiver outlet temperature realistically. Furthermore, based on a statistical uncertainty analysis, a correlation is developed, which allows for predicting the uncertainty of the net power prediction based on the corresponding DNI forecast uncertainty. However, the study reveals significant prediction errors and the demand for further improvement in the accuracy at which local shadings are forecasted. KW - Process prediction KW - DNI forecasting KW - Nowcasting KW - Uncertainty analysis KW - Molten salt receiver system, Y1 - 2024 U6 - https://doi.org/10.52825/solarpaces.v1i.675 SN - 2751-9899 (online) N1 - SolarPACES 2022, 28th International Conference on Concentrating Solar Power and Chemical Energy Systems, 27-30 September, Albuquerque, NM, USA IS - 1 PB - TIB Open Publishing CY - Hannover ER - TY - CHAP A1 - Schulte, Jonas A1 - Schwager, Christian A1 - Frantz, Cathy A1 - Schloms, Felix A1 - Teixeira Boura, Cristiano José A1 - Herrmann, Ulf T1 - Control concept for a molten salt receiver in star design: Development, optimization and testing with cloud passage scenarios T2 - SolarPACES 2022 conference proceedings N2 - A promising approach to reduce the system costs of molten salt solar receivers is to enable the irradiation of the absorber tubes on both sides. The star design is an innovative receiver design, pursuing this approach. The unconventional design leads to new challenges in controlling the system. This paper presents a control concept for a molten salt receiver system in star design. The control parameters are optimized in a defined test cycle by minimizing a cost function. The control concept is tested in realistic cloud passage scenarios based on real weather data. During these tests, the control system showed no sign of unstable behavior, but to perform sufficiently in every scenario further research and development like integrating Model Predictive Controls (MPCs) need to be done. The presented concept is a starting point to do so. KW - Molten salt receiver KW - Star design KW - Control optimization KW - Cloud passages Y1 - 2023 U6 - https://doi.org/10.52825/solarpaces.v1i.693 SN - 2751-9899 (online) N1 - SolarPACES 2022, 28th International Conference on Concentrating Solar Power and Chemical Energy Systems, 27-30 September, Albuquerque, NM, USA IS - 1 PB - TIB Open Publishing CY - Hannover ER - TY - JOUR A1 - Schwager, Christian A1 - Flesch, Robert A1 - Schwarzbözl, Peter A1 - Herrmann, Ulf A1 - Teixeira Boura, Cristiano José T1 - Advanced two phase flow model for transient molten salt receiver system simulation JF - Solar Energy N2 - In order to realistically predict and optimize the actual performance of a concentrating solar power (CSP) plant sophisticated simulation models and methods are required. This paper presents a detailed dynamic simulation model for a Molten Salt Solar Tower (MST) system, which is capable of simulating transient operation including detailed startup and shutdown procedures including drainage and refill. For appropriate representation of the transient behavior of the receiver as well as replication of local bulk and surface temperatures a discretized receiver model based on a novel homogeneous two-phase (2P) flow modelling approach is implemented in Modelica Dymola®. This allows for reasonable representation of the very different hydraulic and thermal properties of molten salt versus air as well as the transition between both. This dynamic 2P receiver model is embedded in a comprehensive one-dimensional model of a commercial scale MST system and coupled with a transient receiver flux density distribution from raytracing based heliostat field simulation. This enables for detailed process prediction with reasonable computational effort, while providing data such as local salt film and wall temperatures, realistic control behavior as well as net performance of the overall system. Besides a model description, this paper presents some results of a validation as well as the simulation of a complete startup procedure. Finally, a study on numerical simulation performance and grid dependencies is presented and discussed. KW - Molten salt solar tower KW - Molten salt receiver system KW - Dynamic simulation KW - Two-phase modelling KW - Transient flux distribution Y1 - 2022 U6 - https://doi.org/10.1016/j.solener.2021.12.065 SN - 0038-092X (print) SN - 1471-1257 (online) VL - 232 SP - 362 EP - 375 PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Gedle, Yibekal A1 - Schmitz, Mark A1 - Gielen, Hans A1 - Schmitz, Pascal A1 - Herrmann, Ulf A1 - Teixeira Boura, Cristiano José A1 - Mahdi, Zahra A1 - Caminos, Ricardo Alexander Chico A1 - Dersch, Jürgen T1 - Analysis of an integrated CSP-PV hybrid power plant T2 - SOLARPACES 2020 N2 - In the past, CSP and PV have been seen as competing technologies. Despite massive reductions in the electricity generation costs of CSP plants, PV power generation is - at least during sunshine hours - significantly cheaper. If electricity is required not only during the daytime, but around the clock, CSP with its inherent thermal energy storage gets an advantage in terms of LEC. There are a few examples of projects in which CSP plants and PV plants have been co-located, meaning that they feed into the same grid connection point and ideally optimize their operation strategy to yield an overall benefit. In the past eight years, TSK Flagsol has developed a plant concept, which merges both solar technologies into one highly Integrated CSP-PV-Hybrid (ICPH) power plant. Here, unlike in simply co-located concepts, as analyzed e.g. in [1] – [4], excess PV power that would have to be dumped is used in electric molten salt heaters to increase the storage temperature, improving storage and conversion efficiency. The authors demonstrate the electricity cost sensitivity to subsystem sizing for various market scenarios, and compare the resulting optimized ICPH plants with co-located hybrid plants. Independent of the three feed-in tariffs that have been assumed, the ICPH plant shows an electricity cost advantage of almost 20% while maintaining a high degree of flexibility in power dispatch as it is characteristic for CSP power plants. As all components of such an innovative concept are well proven, the system is ready for commercial market implementation. A first project is already contracted and in early engineering execution. KW - Hybrid energy system KW - Power plants KW - Electricity generation KW - Energy storage KW - Associated liquids Y1 - 2022 SN - 978-0-7354-4195-8 U6 - https://doi.org/10.1063/5.0086236 SN - 1551-7616 (online) SN - 0094-243X (print) N1 - SOLARPACES 2020: 26th International Conference on Concentrating Solar Power and Chemical Energy Systems, 28 September–2 October 2020, Freiburg, Germany IS - 2445 / 1 PB - AIP conference proceedings / American Institute of Physics CY - Melville, NY ER - TY - CHAP A1 - Mahdi, Zahra A1 - Dersch, Jürgen A1 - Schmitz, Pascal A1 - Dieckmann, Simon A1 - Caminos, Ricardo Alexander Chico A1 - Teixeira Boura, Cristiano José A1 - Herrmann, Ulf A1 - Schwager, Christian A1 - Schmitz, Mark A1 - Gielen, Hans A1 - Gedle, Yibekal A1 - Büscher, Rauno T1 - Technical assessment of Brayton cycle heat pumps for the integration in hybrid PV-CSP power plants T2 - SOLARPACES 2020 N2 - The hybridization of Concentrated Solar Power (CSP) and Photovoltaics (PV) systems is a promising approach to reduce costs of solar power plants, while increasing dispatchability and flexibility of power generation. High temperature heat pumps (HT HP) can be utilized to boost the salt temperature in the thermal energy storage (TES) of a Parabolic Trough Collector (PTC) system from 385 °C up to 565 °C. A PV field can supply the power for the HT HP, thus effectively storing the PV power as thermal energy. Besides cost-efficiently storing energy from the PV field, the power block efficiency of the overall system is improved due to the higher steam parameters. This paper presents a technical assessment of Brayton cycle heat pumps to be integrated in hybrid PV-CSP power plants. As a first step, a theoretical analysis was carried out to find the most suitable working fluid. The analysis included the fluids Air, Argon (Ar), Nitrogen (N2) and Carbon dioxide (CO2). N2 has been chosen as the optimal working fluid for the system. After the selection of the ideal working medium, different concepts for the arrangement of a HT HP in a PV-CSP hybrid power plant were developed and simulated in EBSILON®Professional. The concepts were evaluated technically by comparing the number of components required, pressure losses and coefficient of performance (COP). KW - Solar thermal technologies KW - Hybrid energy system KW - Concentrated solar power KW - Power plants KW - Energy storage Y1 - 2022 SN - 978-0-7354-4195-8 U6 - https://doi.org/10.1063/5.0086269 SN - 1551-7616 (online) SN - 0094-243X (print) N1 - SOLARPACES 2020: 26th International Conference on Concentrating Solar Power and Chemical Energy Systems, 28 September–2 October 2020, Freiburg, Germany IS - 2445 / 1 PB - AIP conference proceedings / American Institute of Physics CY - Melville, NY ER - TY - CHAP A1 - Losse, Ann-Kathrin A1 - Gehrke, Melanie A1 - Ullrich, André A1 - Czarnecki, Christian A1 - Sultanow, Eldar A1 - Breithaupt, Carsten A1 - Koch, Christian T1 - Entwicklung einer Open-Data-Referenzarchitektur für die Luftfahrtindustrie T2 - INFORMATIK 2022 - Informatik in den Naturwissenschaften, Proceedings N2 - Open Data impliziert die freie Zugänglichkeit, Verfügbarkeit und Wiederverwendbarkeit von Datensätzen. Obwohl hochwertige Datensätze öffentlich verfügbar sind, ist der Zugang zu diesen und die Transparenz über die Formate nicht immer gegeben. Dies mindert die optimale Nutzung des Potenzials zur Wertschöpfung, trotz der vorherrschenden Einigkeit über ihre Chancen. Denn Open Data ermöglicht das Vorantreiben von Compliance-Themen wie Transparenz und Rechenschaftspflicht bis hin zur Förderung von Innovationen. Die Nutzung von Open Data erfordert Mut und eine gemeinsame Anstrengung verschiedener Akteure und Branchen. Im Rahmen des vorliegenden Beitrags werden auf Grundlage des Design Science-Ansatzes eine Open Data Capability Map sowie darauf aufbauend eine Datenarchitektur für Open Data in der Luftfahrtindustrie an einem Beispiel entwickelt. Y1 - 2022 SN - 978-3-88579-720-3 U6 - https://doi.org/10.18420/inf2022_103 SN - 1617-5468 N1 - INFORMATIK 2022, 26. - 30. September 2022, Hamburg SP - 1203 EP - 1209 PB - GI - Gesellschaft für Informatik CY - Bonn ER - TY - GEN A1 - Keimer, Jona A1 - Girbig, Leo A1 - Mayntz, Joscha A1 - Tegtmeyer, Philipp A1 - Wendland, Frederik A1 - Dahman, Peter A1 - Fisher, Alex A1 - Dorrington, Graham T1 - Flight mission optimization for eco-efficiency in consideration of electric regeneration and atmospheric conditions T2 - AIAA AVIATION 2022 Forum N2 - The development and operation of hybrid or purely electrically powered aircraft in regional air mobility is a significant challenge for the entire aviation sector. This technology is expected to lead to substantial advances in flight performance, energy efficiency, reliability, safety, noise reduction, and exhaust emissions. Nevertheless, any consumed energy results in heat or carbon dioxide emissions and limited electric energy storage capabilities suppress commercial use. Therefore, the significant challenges to achieving eco-efficient aviation are increased aircraft efficiency, the development of new energy storage technologies, and the optimization of flight operations. Two major approaches for higher eco-efficiency are identified: The first one, is to take horizontal and vertical atmospheric motion phenomena into account. Where, in particular, atmospheric waves hold exciting potential. The second one is the use of the regeneration ability of electric aircraft. The fusion of both strategies is expected to improve efficiency. The objective is to reduce energy consumption during flight while not neglecting commercial usability and convenient flight characteristics. Therefore, an optimized control problem based on a general aviation class aircraft has to be developed and validated by flight experiments. The formulated approach enables a development of detailed knowledge of the potential and limitations of optimizing flight missions, considering the capability of regeneration and atmospheric influences to increase efficiency and range. Y1 - 2022 U6 - https://doi.org/10.2514/6.2022-4118 N1 - AIAA AVIATION 2022 Forum, June 27-July 1, 2022 Chicago, IL & Virtual PB - AIAA CY - Reston, Va. ER - TY - CHAP A1 - Mayntz, Joscha A1 - Keimer, Jona A1 - Dahmann, Peter A1 - Hille, Sebastian A1 - Stumpf, Eike A1 - Fisher, Alex A1 - Dorrington, Graham T1 - Electrical Drive and Regeneration in General Aviation Flight with Propellers T2 - Deutscher Luft- und Raumfahrtkongress 2020 N2 - Electric flight has the potential for a more sustainable and energy-saving way of aviation compared to fossil fuel aviation. The electric motor can be used as a generator inflight to regenerate energy during descent. Three different approaches to regenerating with electric propeller powertrains are proposed in this paper. The powertrain is to be set up in a wind tunnel to determine the propeller efficiency in both working modes as well as the noise emissions. Furthermore, the planned flight tests are discussed. In preparation for these tests, a yaw stability analysis is performed with the result that the aeroplane is controllable during flight and in the most critical failure case. The paper shows the potential for inflight regeneration and addresses the research gaps in the dual role of electric powertrains for propulsion and regeneration of general aviation aircraft. KW - Propeller Aerodynamics KW - Flight Tests KW - Flight Mechanics KW - Electrical Flight KW - Inflight Regeneration, Recuperation Y1 - 2022 U6 - https://doi.org/10.25967/530100 N1 - Deutscher Luft- und Raumfahrtkongress 2020, 1. - 3. September 2020, Online PB - DGLR CY - Bonn ER - TY - JOUR A1 - Kleefeld, Andreas A1 - Zimmermann, M. ED - Constanda, Christian ED - Bodmann, Bardo E.J. ED - Harris, Paul J. T1 - Computing Elastic Interior Transmission Eigenvalues JF - Integral Methods in Science and Engineering N2 - An alternative method is presented to numerically compute interior elastic transmission eigenvalues for various domains in two dimensions. This is achieved by discretizing the resulting system of boundary integral equations in combination with a nonlinear eigenvalue solver. Numerical results are given to show that this new approach can provide better results than the finite element method when dealing with general domains. Y1 - 2022 SN - 978-3-031-07171-3 U6 - https://doi.org/10.1007/978-3-031-07171-3_10 N1 - Corresponding author: Andreas Kleefeld SP - 139 EP - 155 PB - Birkhäuser CY - Cham ER - TY - CHAP A1 - Burgeth, Bernhard A1 - Kleefeld, Andreas A1 - Zhang, Eugene A1 - Zhang, Yue ED - Baudrier, Étienne ED - Naegel, Benoît ED - Krähenbühl, Adrien ED - Tajine, Mohamed T1 - Towards Topological Analysis of Non-symmetric Tensor Fields via Complexification T2 - Discrete Geometry and Mathematical Morphology N2 - Fields of asymmetric tensors play an important role in many applications such as medical imaging (diffusion tensor magnetic resonance imaging), physics, and civil engineering (for example Cauchy-Green-deformation tensor, strain tensor with local rotations, etc.). However, such asymmetric tensors are usually symmetrized and then further processed. Using this procedure results in a loss of information. A new method for the processing of asymmetric tensor fields is proposed restricting our attention to tensors of second-order given by a 2x2 array or matrix with real entries. This is achieved by a transformation resulting in Hermitian matrices that have an eigendecomposition similar to symmetric matrices. With this new idea numerical results for real-world data arising from a deformation of an object by external forces are given. It is shown that the asymmetric part indeed contains valuable information. Y1 - 2022 SN - 978-3-031-19897-7 U6 - https://doi.org/10.1007/978-3-031-19897-7_5 N1 - Second International Joint Conference, DGMM 2022, Strasbourg, France, October 24–27, 2022 N1 - Corresponding author: Andreas Kleefeld SP - 48 EP - 59 PB - Springer CY - Cham ER - TY - JOUR A1 - Harris, Isaac A1 - Kleefeld, Andreas T1 - Analysis and computation of the transmission eigenvalues with a conductive boundary condition JF - Applicable Analysis N2 - We provide a new analytical and computational study of the transmission eigenvalues with a conductive boundary condition. These eigenvalues are derived from the scalar inverse scattering problem for an inhomogeneous material with a conductive boundary condition. The goal is to study how these eigenvalues depend on the material parameters in order to estimate the refractive index. The analytical questions we study are: deriving Faber–Krahn type lower bounds, the discreteness and limiting behavior of the transmission eigenvalues as the conductivity tends to infinity for a sign changing contrast. We also provide a numerical study of a new boundary integral equation for computing the eigenvalues. Lastly, using the limiting behavior we will numerically estimate the refractive index from the eigenvalues provided the conductivity is sufficiently large but unknown. KW - Boundary integral equations KW - Inverse spectral problem KW - Conductive boundary condition KW - Transmission eigenvalues Y1 - 2020 U6 - https://doi.org/10.1080/00036811.2020.1789598 SN - 1563-504X VL - 101 IS - 6 SP - 1880 EP - 1895 PB - Taylor & Francis CY - London ER - TY - CHAP A1 - Golland, Alexander ED - Riechert, Anne ED - Wilmer, Thomas T1 - Kommentierung von § 7 Telekommunikation-Telemedien-Datenschutzgesetz T2 - TTDSG Y1 - 2022 SN - 978-3-503-20978-1 N1 - Gedruckte Ausgabe unter 21 QRUG 2 verfügbar. SP - 145 EP - 151 PB - Erich Schmidt CY - Berlin ER - TY - CHAP A1 - Golland, Alexander ED - Riechert, Anne ED - Wilmer, Thomas T1 - Kommentierung von § 26 Telekommunikation-Telemedien-Datenschutzgesetz T2 - TTDSG Y1 - 2022 SN - 978-3-503-20978-1 N1 - Gedruckte Ausgabe unter 21 QRUG 2 verfügbar. SP - 439 EP - 474 PB - Erich Schmidt CY - Berlin ER - TY - CHAP A1 - Langohr, Philipp A1 - Bung, Daniel Bernhard A1 - Crookston, Brian M. ED - Ortega-Sánchez, Miguel T1 - Hybrid investigation of labyrinth weirs: Discharge capacity and energy dissipation T2 - Proceedings of the 39th IAHR World Congress N2 - The replacement of existing spillway crests or gates with labyrinth weirs is a proven techno-economical means to increase the discharge capacity when rehabilitating existing structures. However, additional information is needed regarding energy dissipation of such weirs, since due to the folded weir crest, a three-dimensional flow field is generated, yielding more complex overflow and energy dissipation processes. In this study, CFD simulations of labyrinth weirs were conducted 1) to analyze the discharge coefficients for different discharges to compare the Cd values to literature data and 2) to analyze and improve energy dissipation downstream of the structure. All tests were performed for a structure at laboratory scale with a height of approx. P = 30.5 cm, a ratio of the total crest length to the total width of 4.7, a sidewall angle of 10° and a quarter-round weir crest shape. Tested headwater ratios were 0.089 ≤ HT/P ≤ 0.817. For numerical simulations, FLOW-3D Hydro was employed, solving the RANS equations with use of finite-volume method and RNG k-ε turbulence closure. In terms of discharge capacity, results were compared to data from physical model tests performed at the Utah Water Research Laboratory (Utah State University), emphasizing higher discharge coefficients from CFD than from the physical model. For upstream heads, some discrepancy in the range of ± 1 cm between literature, CFD and physical model tests was identified with a discussion regarding differences included in the manuscript. For downstream energy dissipation, variable tailwater depths were considered to analyze the formation and sweep-out of a hydraulic jump. It was found that even for high discharges, relatively low downstream Froude numbers were obtained due to high energy dissipation involved by the three-dimensional flow between the sidewalls. The effects of some additional energy dissipation devices, e.g. baffle blocks or end sills, were also analyzed. End sills were found to be non-effective. However, baffle blocks with different locations may improve energy dissipation downstream of labyrinth weirs. Y1 - 2022 SN - 978-90-832612-1-8 U6 - https://doi.org/10.3850/IAHR-39WC252171192022738 SN - 2521-7119 (print) SN - 2521-716X (online) N1 - 39th IAHR World Congress, 19. - 24. Juni 2022, Granada SP - 2313 EP - 2318 PB - International Association for Hydro-Environment Engineering and Research (IAHR) CY - Madrid ER - TY - CHAP A1 - Crookston, Brian M. A1 - Bung, Daniel Bernhard ED - Ortega-Sánchez, Miguel T1 - Application of RGB-D cameras in hydraulic laboratory studies T2 - Proceedings of the 39th IAHR World Congress N2 - Non-intrusive measuring techniques have attained a lot of interest in relation to both hydraulic modeling and prototype applications. Complimenting acoustic techniques, significant progress has been made for the development of new optical methods. Computer vision techniques can help to extract new information, e. g. high-resolution velocity and depth data, from videos captured with relatively inexpensive, consumer-grade cameras. Depth cameras are sensors providing information on the distance between the camera and observed features. Currently, sensors with different working principles are available. Stereoscopic systems reference physical image features (passive system) from two perspectives; in order to enhance the number of features and improve the results, a sensor may also estimate the disparity from a detected light to its original projection (active stereo system). In the current study, the RGB-D camera Intel RealSense D435, working on such stereo vision principle, is used in different, typical hydraulic modeling applications. All tests have been conducted at the Utah Water Research Laboratory. This paper will demonstrate the performance and limitations of the RGB-D sensor, installed as a single camera and as camera arrays, applied to 1) detect the free surface for highly turbulent, aerated hydraulic jumps, for free-falling jets and for an energy dissipation basin downstream of a labyrinth weir and 2) to monitor local scours upstream and downstream of a Piano Key Weir. It is intended to share the authors’ experiences with respect to camera settings, calibration, lightning conditions and other requirements in order to promote this useful, easily accessible device. Results will be compared to data from classical instrumentation and the literature. It will be shown that even in difficult application, e. g. the detection of a highly turbulent, fluctuating free-surface, the RGB-D sensor may yield similar accuracy as classical, intrusive probes. Y1 - 2022 SN - 978-90-832612-1-8 U6 - https://doi.org/10.3850/IAHR-39WC252171192022964 SN - 2521-7119 (print) SN - 2521-716X (online) N1 - 39th IAHR World Congress, 19. - 24. Juni 2022, Granada SP - 5127 EP - 5133 PB - International Association for Hydro-Environment Engineering and Research (IAHR) CY - Madrid ER - TY - BOOK A1 - Kurz, Melanie A1 - Schwer, Thilo T1 - Raster, Regeln, Ratio : Systematiken und Normungen im Design des 20. Jahrhunderts / herausgegeben von Melanie Kurz und Thilo Schwer T3 - Schriften / Gesellschaft für Designgeschichte Y1 - 2022 SN - 978-3-89986-380-2 N1 - Band 5 PB - avedition CY - Stuttgart ER - TY - JOUR A1 - Fabo, Sabine ED - Wirth, Jacob T1 - Das Parasitäre in der Pandemie JF - Parasite Art Y1 - 2022 IS - Issue 2 SP - 8 EP - 11 PB - Parasite Art ER - TY - CHAP A1 - Kurz, Melanie T1 - Vom Werkbundstreit bis zur Papierformatnormung - welche Rolle der Chemie-Nobelpreisträger Friedrich Wilhelm Ostwald bei Typisierungsbestrebungen im Design spielt T2 - Raster, Regeln, Ratio : Systematiken und Normungen des 20. Jahrhunderts Y1 - 2022 SN - 978-3-89986-380-2 VL - 2022 SP - 6 EP - 17 PB - avedition CY - Stuttgart ER - TY - CHAP A1 - Fabo, Sabine T1 - Pandemische Momente T2 - Interaktion – Emotion – Desinfektion ; Kunst und Museum in Zeiten von Corona / Birgit Richard, Jana Müller, Niklas von Reischach (Hrsg.) Y1 - 2022 SN - 978-3-593-51520-5 (Print) SN - 978-3-593-44960-9 (E-Book) SP - 137 EP - 140 PB - Campus CY - Frankfurt ; New York ER - TY - BOOK A1 - Kurz, Melanie A1 - Schwer, Thilo T1 - Geschichte des Designs N2 - Dieser Band bietet einen kompakten Überblick über die wichtigsten Stationen des Produktdesigns vom Beginn der Industrialisierung bis heute. Im Zentrum stehen ikonische Alltagsgegenstände vom Thonet-Stuhl bis zum iPhone. Anschaulich und kenntnisreich nehmen Melanie Kurz und Thilo Schwer dabei auch die gesellschaftspolitische Situation, in der die Objekte entstanden sind, in den Blick. Y1 - 2022 SN - 978-3-406-78813-0 PB - Beck CY - München ET - 1. Auflage ER - TY - CHAP A1 - Fabo, Sabine T1 - Plüschviren – Zur Konstruktion von Nähe in Zeiten der Pandemie T2 - Interaktion – Emotion – Desinfektion ; Kunst und Museum in Zeiten von Corona / Birgit Richard, Jana Müller, Niklas von Reischach (Hrsg.) Y1 - 2022 SN - 978-3-593-51520-5 (Print) SN - 978-3-593-44960-9 (E-Book) SP - 45 EP - 69 PB - Campus CY - Frankfurt ; New York ER - TY - THES A1 - Biewendt, Marcel T1 - Socio-Economic challenges in sustainability and resource management N2 - This dissertation uses in first stage a macroeconomic investigation to examine the dependence, influence and corruption of socio-economic development through effects of sustainability and resource management. The conducted research found that the state's dependence on its citizens decreases when the state's sources of revenue are largely detached and independent of the citizens' financial resources. In this case, financial resources are taxes and duties provided by the citizens. One possible consequence is the restriction of state investment in its citizens. Both the qualitative literature review and the quantitative data analysis revealed a negative correlation between socio-economic development and the resource economy's share of GDP for the period under study. The microeconomic investigation was primarily conducted through an intensive literature review. It was shown that the rebound effect as such is already very well researched. However, it also became clear that avoidance strategies for the rebound effect and links to sustainability initiatives are scarce or non-existent. The need for a redesign of the impact analysis with regard to technological innovations and their influence on resource consumption and resource management has become clear on the basis of the present study. Further, emerging and developing countries in particular, which will be confronted in the foreseeable future not only with the fundamental problems of resource abundance in the overall economic context, but also with the issues of their sustainable use, should be confronted with these problems as early as possible in order to find solutions in a timely manner. KW - Efficiency side-effects KW - Resource-optimization KW - Rebound effect KW - Socio-economics Y1 - 2022 PB - Hungarian University of Agriculture and Life Sciences ER - TY - JOUR A1 - Uysal, Karya A1 - Creutz, Till A1 - Firat, Ipek Seda A1 - Artmann, Gerhard A1 - Teusch, Nicole A1 - Temiz Artmann, Aysegül T1 - Bio-functionalized ultra-thin, large-area and waterproof silicone membranes for biomechanical cellular loading and compliance experiments JF - Polymers N2 - Biocompatibility, flexibility and durability make polydimethylsiloxane (PDMS) membranes top candidates in biomedical applications. CellDrum technology uses large area, <10 µm thin membranes as mechanical stress sensors of thin cell layers. For this to be successful, the properties (thickness, temperature, dust, wrinkles, etc.) must be precisely controlled. The following parameters of membrane fabrication by means of the Floating-on-Water (FoW) method were investigated: (1) PDMS volume, (2) ambient temperature, (3) membrane deflection and (4) membrane mechanical compliance. Significant differences were found between all PDMS volumes and thicknesses tested (p < 0.01). They also differed from the calculated values. At room temperatures between 22 and 26 °C, significant differences in average thickness values were found, as well as a continuous decrease in thicknesses within a 4 °C temperature elevation. No correlation was found between the membrane thickness groups (between 3–4 µm) in terms of deflection and compliance. We successfully present a fabrication method for thin bio-functionalized membranes in conjunction with a four-step quality management system. The results highlight the importance of tight regulation of production parameters through quality control. The use of membranes described here could also become the basis for material testing on thin, viscous layers such as polymers, dyes and adhesives, which goes far beyond biological applications. Y1 - 2022 SN - 2073-4360 VL - 14 IS - 11 SP - 2213 PB - MDPI CY - Basel ER - TY - JOUR A1 - Uysal, Karya A1 - Firat, Ipek Serat A1 - Creutz, Till A1 - Aydin, Inci Cansu A1 - Artmann, Gerhard A1 - Teusch, Nicole A1 - Temiz Artmann, Aysegül T1 - A novel in vitro wound healing assay using free-standing, ultra-thin PDMS membranes JF - membranes N2 - Advances in polymer science have significantly increased polymer applications in life sciences. We report the use of free-standing, ultra-thin polydimethylsiloxane (PDMS) membranes, called CellDrum, as cell culture substrates for an in vitro wound model. Dermal fibroblast monolayers from 28- and 88-year-old donors were cultured on CellDrums. By using stainless steel balls, circular cell-free areas were created in the cell layer (wounding). Sinusoidal strain of 1 Hz, 5% strain, was applied to membranes for 30 min in 4 sessions. The gap circumference and closure rate of un-stretched samples (controls) and stretched samples were monitored over 4 days to investigate the effects of donor age and mechanical strain on wound closure. A significant decrease in gap circumference and an increase in gap closure rate were observed in trained samples from younger donors and control samples from older donors. In contrast, a significant decrease in gap closure rate and an increase in wound circumference were observed in the trained samples from older donors. Through these results, we propose the model of a cell monolayer on stretchable CellDrums as a practical tool for wound healing research. The combination of biomechanical cell loading in conjunction with analyses such as gene/protein expression seems promising beyond the scope published here. Y1 - 2022 U6 - https://doi.org/10.3390/membranes13010022 N1 - This article belongs to the Special Issue "Latest Scientific Discoveries in Polymer Membranes" VL - 2023 IS - 13(1) PB - MDPI CY - Basel ER - TY - CHAP A1 - Weiss, Christian A1 - Heslenfeld, Jonas A1 - Saewe, Jasmin Kathrin A1 - Bremen, Sebastian A1 - Häfner, Constantin Leon T1 - Investigation on the influence of powder humidity in Laser Powder Bed Fusion (LPBF) T2 - Procedia CIRP 12th CIRP Conference on Photonic Technologies [LANE 2022] N2 - In the Laser Powder Bed Fusion (LPBF) process, parts are built out of metal powder material by exposure of a laser beam. During handling operations of the powder material, several influencing factors can affect the properties of the powder material and therefore directly influence the processability during manufacturing. Contamination by moisture due to handling operations is one of the most critical aspects of powder quality. In order to investigate the influences of powder humidity on LPBF processing, four materials (AlSi10Mg, Ti6Al4V, 316L and IN718) are chosen for this study. The powder material is artificially humidified, subsequently characterized, manufactured into cubic samples in a miniaturized process chamber and analyzed for their relative density. The results indicate that the processability and reproducibility of parts made of AlSi10Mg and Ti6Al4V are susceptible to humidity, while IN718 and 316L are barely influenced. KW - LPBF KW - Additive Manufacturing KW - Powder Material KW - Humidity Y1 - 2022 U6 - https://doi.org/10.1016/j.procir.2022.08.102 SN - 2212-8271 N1 - 12th CIRP Conference on Photonic Technologies [LANE 2022], 04. September 2022 bis 08. September 2022, Fürth VL - 111 SP - 115 EP - 120 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Angermann, Susanne A1 - Günthner, Roman A1 - Hanssen, Henner A1 - Lorenz, Georg A1 - Braunisch, Matthias C. A1 - Steubl, Dominik A1 - Matschkal, Julia A1 - Kemmner, Stephan A1 - Hausinger, Renate A1 - Block, Zenonas A1 - Haller, Bernhard A1 - Heemann, Uwe A1 - Kotliar, Konstantin A1 - Grimmer, Timo A1 - Schmaderer, Christoph T1 - Cognitive impairment and microvascular function in end-stage renal disease JF - International Journal of Methods in Psychiatric Research (MPR) N2 - Objective Hemodialysis patients show an approximately threefold higher prevalence of cognitive impairment compared to the age-matched general population. Impaired microcirculatory function is one of the assumed causes. Dynamic retinal vessel analysis is a quantitative method for measuring neurovascular coupling and microvascular endothelial function. We hypothesize that cognitive impairment is associated with altered microcirculation of retinal vessels. Methods 152 chronic hemodialysis patients underwent cognitive testing using the Montreal Cognitive Assessment. Retinal microcirculation was assessed by Dynamic Retinal Vessel Analysis, which carries out an examination recording retinal vessels' reaction to a flicker light stimulus under standardized conditions. Results In unadjusted as well as in adjusted linear regression analyses a significant association between the visuospatial executive function domain score of the Montreal Cognitive Assessment and the maximum arteriolar dilation as response of retinal arterioles to the flicker light stimulation was obtained. Conclusion This is the first study determining retinal microvascular function as surrogate for cerebral microvascular function and cognition in hemodialysis patients. The relationship between impairment in executive function and reduced arteriolar reaction to flicker light stimulation supports the involvement of cerebral small vessel disease as contributing factor for the development of cognitive impairment in this patient population and might be a target for noninvasive disease monitoring and therapeutic intervention. KW - cerebral small vessel disease KW - cognitive impairment KW - dialysis KW - retinal vessels Y1 - 2022 U6 - https://doi.org/10.1002/mpr.1909 SN - 1049-8931 (Print) SN - 1557-0657 (Online) VL - 31 IS - 2 SP - 1 EP - 10 PB - Wiley ER - TY - JOUR A1 - Kotliar, Konstantin A1 - Ortner, Marion A1 - Conradi, Anna A1 - Hacker, Patricia A1 - Hauser, Christine A1 - Günthner, Roman A1 - Moser, Michaela A1 - Muggenthaler, Claudia A1 - Diehl-Schmid, Janine A1 - Priller, Josef A1 - Schmaderer, Christoph A1 - Grimmer, Timo T1 - Altered retinal cerebral vessel oscillation frequencies in Alzheimer's disease compatible with impaired amyloid clearance JF - Neurobiology of Aging N2 - Retinal vessels are similar to cerebral vessels in their structure and function. Moderately low oscillation frequencies of around 0.1 Hz have been reported as the driving force for paravascular drainage in gray matter in mice and are known as the frequencies of lymphatic vessels in humans. We aimed to elucidate whether retinal vessel oscillations are altered in Alzheimer's disease (AD) at the stage of dementia or mild cognitive impairment (MCI). Seventeen patients with mild-to-moderate dementia due to AD (ADD); 23 patients with MCI due to AD, and 18 cognitively healthy controls (HC) were examined using Dynamic Retinal Vessel Analyzer. Oscillatory temporal changes of retinal vessel diameters were evaluated using mathematical signal analysis. Especially at moderately low frequencies around 0.1 Hz, arterial oscillations in ADD and MCI significantly prevailed over HC oscillations and correlated with disease severity. The pronounced retinal arterial vasomotion at moderately low frequencies in the ADD and MCI groups would be compatible with the view of a compensatory upregulation of paravascular drainage in AD and strengthen the amyloid clearance hypothesis. KW - Alzheimer's disease KW - Retinal vessel analysis KW - Vasomotions KW - Pulsations KW - Mild cognitive impairment Y1 - 2022 U6 - https://doi.org/10.1016/j.neurobiolaging.2022.08.012 SN - 0197-4580 VL - 120 SP - 117 EP - 127 PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Moorkamp, Wilfried A1 - Peterson, Leif Arne A1 - Uibel, Thomas ED - Fouad, Nabil A. T1 - Nachhaltige Holzbrücken für Geh- und Radwege T2 - Bauphysik Kalender 2022: Holzbau, 22. Jahrgang N2 - Am Lehr- und Forschungsgebiet Holzbau der Fachhochschule Aachen wurden im Rahmen des Forschungsvorhabens „Nachhaltige Standardbrücken in Holzbauweise“ Standardtypen für Geh- und Radwegbrücken entwickelt. Die Brücken sind durch konsequente Umsetzungen von Maßnahmen des konstruktiven Holzschutzes für eine Nutzung von mehr als 80~Jahren konzipiert. Innovative Lösungen für Bauteile und Anschlüsse sowie Materialalternativen im Bereich des Belages und der Geländer ermöglichen eine wartungsarme Konstruktion und tragen somit zur Wirtschaftlichkeit und Nachhaltigkeit bei. Um den Einsatz der entwickelten Standardbrückentypen in der Praxis zu erleichtern, wurden Leistungsverzeichnisse, Musterstatiken, Musterzeichnungen und umfangreiche Detailkataloge als Unterstützung für Planer und Bauherren erstellt. Damit die Randbedingungen für eine lange Lebensdauer während der Nutzung der Brücke erhalten bleiben, wurden Leitfäden für die Pflege und Wartung sowie für die Brückenprüfung erarbeitet. Der Beitrag gibt Einblicke in das Forschungsvorhaben und seine Resultate. Y1 - 2022 SN - 9783433033609 (Print) SN - 9783433611081 (Online) U6 - https://doi.org/10.1002/9783433611081.ch17 SP - 574 EP - 592 PB - Ernst & Sohn CY - Berlin ER - TY - JOUR A1 - Werfel, Stanislas A1 - Günthner, Roman A1 - Hapfelmeier, Alexander A1 - Hanssen, Henner A1 - Kotliar, Konstantin A1 - Heemann, Uwe A1 - Schmaderer, Christoph ED - Guzik, Tomasz J. T1 - Identification of cardiovascular high-risk groups from dynamic retinal vessel signals using untargeted machine learning JF - Cardiovascular Research N2 - Dynamic retinal vessel analysis (DVA) provides a non-invasive way to assess microvascular function in patients and potentially to improve predictions of individual cardiovascular (CV) risk. The aim of our study was to use untargeted machine learning on DVA in order to improve CV mortality prediction and identify corresponding response alterations. KW - Machine learning KW - Retinal vessels KW - Microcirculation KW - Haemodialysis KW - Myocardial infarction and cardiac death Y1 - 2022 U6 - https://doi.org/10.1093/cvr/cvab040 SN - 0008-6363 VL - 118 IS - 2 SP - 612 EP - 621 PB - Oxford University Press CY - Oxford ER - TY - CHAP A1 - Veettil, Yadu Krishna Morassery A1 - Rakshit, Shantam A1 - Schopen, Oliver A1 - Kemper, Hans A1 - Esch, Thomas A1 - Shabani, Bahman ED - Bin Abdollah, Mohd Fadzli ED - Amiruddin, Hilmi ED - Singh, Amrik Singh Phuman ED - Munir, Fudhail Abdul ED - Ibrahim, Asriana T1 - Automated Control System Strategies to Ensure Safety of PEM Fuel Cells Using Kalman Filters T2 - Proceedings of the 7th International Conference and Exhibition on Sustainable Energy and Advanced Materials (ICE-SEAM 2021), Melaka, Malaysia N2 - Having well-defined control strategies for fuel cells, that can efficiently detect errors and take corrective action is critically important for safety in all applications, and especially so in aviation. The algorithms not only ensure operator safety by monitoring the fuel cell and connected components, but also contribute to extending the health of the fuel cell, its durability and safe operation over its lifetime. While sensors are used to provide peripheral data surrounding the fuel cell, the internal states of the fuel cell cannot be directly measured. To overcome this restriction, Kalman Filter has been implemented as an internal state observer. Other safety conditions are evaluated using real-time data from every connected sensor and corrective actions automatically take place to ensure safety. The algorithms discussed in this paper have been validated thorough Model-in-the-Loop (MiL) tests as well as practical validation at a dedicated test bench. KW - control system KW - PEM fuel cells KW - Kalman filter Y1 - 2022 SN - 978-981-19-3178-9 SN - 978-981-19-3179-6 (E-Book) U6 - https://doi.org/10.1007/978-981-19-3179-6_55 SN - 2195-4356 N1 - 7th International Conference and Exhibition on Sustainable Energy and Advanced Material (ICE-SEAM 2021), Universiti Teknikal Malaysia Melaka (UTeM), Malaysia, in association with the Universitas Sebelas Maret (UNS), Indonesia, 23 November 2021 SP - 296 EP - 299 PB - Springer Nature CY - Singapore ER - TY - CHAP A1 - Sattler, Johannes Christoph A1 - Atti, Vikrama A1 - Alexopoulos, Spiros A1 - Teixeira Boura, Cristiano José A1 - Herrmann, Ulf A1 - Dutta, Siddharth A1 - Kioutsioukis, Ioannis T1 - DNI forecast tool for the smart operation of a parabolic trough collector system with concrete thermal energy storage: Theory, results and outlook T2 - SolarPACES 2022 conference proceedings N2 - This work presents a basic forecast tool for predicting direct normal irradiance (DNI) in hourly resolution, which the Solar-Institut Jülich (SIJ) is developing within a research project. The DNI forecast data shall be used for a parabolic trough collector (PTC) system with a concrete thermal energy storage (C-TES) located at the company KEAN Soft Drinks Ltd in Limassol, Cyprus. On a daily basis, 24-hour DNI prediction data in hourly resolution shall be automatically produced using free or very low-cost weather forecast data as input. The purpose of the DNI forecast tool is to automatically transfer the DNI forecast data on a daily basis to a main control unit (MCU). The MCU automatically makes a smart decision on the operation mode of the PTC system such as steam production mode and/or C-TES charging mode. The DNI forecast tool was evaluated using historical data of measured DNI from an on-site weather station, which was compared to the DNI forecast data. The DNI forecast tool was tested using data from 56 days between January and March 2022, which included days with a strong variation in DNI due to cloud passages. For the evaluation of the DNI forecast reliability, three categories were created and the forecast data was sorted accordingly. The result was that the DNI forecast tool has a reliability of 71.4 % based on the tested days. The result fulfils SIJ’s aim to achieve a reliability of around 70 %, but SIJ aims to still improve the DNI forecast quality. KW - Direct normal irradiance forecast KW - DNI forecast KW - Parabolic trough collector KW - PTC KW - Thermal Energy Storage Y1 - 2024 U6 - https://doi.org/10.52825/solarpaces.v1i.731 SN - 2751-9899 (online) N1 - SolarPACES 2022, 28th International Conference on Concentrating Solar Power and Chemical Energy Systems, 27-30 September, Albuquerque, NM, USA IS - 1 PB - TIB Open Publishing CY - Hannover ER - TY - CHAP A1 - Hoffschmidt, Bernhard A1 - Alexopoulos, Spiros A1 - Rau, Christoph A1 - Sattler, Johannes, Christoph A1 - Anthrakidis, Anette A1 - Teixeira Boura, Cristiano José A1 - O’Connor, B. A1 - Chico Caminos, R.A. A1 - Rendón, C. A1 - Hilger, P. T1 - Concentrating solar power T2 - Comprehensive Renewable Energy (Second Edition) / Volume 3: Solar Thermal Systems: Components and Applications N2 - The focus of this chapter is the production of power and the use of the heat produced from concentrated solar thermal power (CSP) systems. The chapter starts with the general theoretical principles of concentrating systems including the description of the concentration ratio, the energy and mass balance. The power conversion systems is the main part where solar-only operation and the increase in operational hours. Solar-only operation include the use of steam turbines, gas turbines, organic Rankine cycles and solar dishes. The operational hours can be increased with hybridization and with storage. Another important topic is the cogeneration where solar cooling, desalination and of heat usage is described. Many examples of commercial CSP power plants as well as research facilities from the past as well as current installed and in operation are described in detail. The chapter closes with economic and environmental aspects and with the future potential of the development of CSP around the world. KW - Central receiver power plant KW - Concentrated systems KW - Gas turbine KW - Hybridization KW - Power conversion systems Y1 - 2022 SN - 978-0-12-819734-9 SP - 670 EP - 724 PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Schopen, Oliver A1 - Shabani, Bahman A1 - Esch, Thomas A1 - Kemper, Hans A1 - Shah, Neel ED - Rahim, S.A. ED - As'arry, A. ED - Zuhri, M.Y.M. ED - Harmin, M.Y. ED - Rezali, K.A.M. ED - Hairuddin, A.A. T1 - Quantitative evaluation of health management designs for fuel cell systems in transport vehicles T2 - 2nd UNITED-SAIG International Conference Proceedings N2 - Focusing on transport vehicles, mainly with regard to aviation applications, this paper presents compilation and subsequent quantitative evaluation of methods aimed at building an optimum integrated health management solution for fuel cell systems. The methods are divided into two different main types and compiled in a related scheme. Furthermore, different methods are analysed and evaluated based on parameters specific to the aviation context of this study. Finally, the most suitable method for use in fuel cell health management systems is identified and its performance and suitability is quantified. KW - aviation application KW - health management systems KW - fuel cell systems Y1 - 2022 N1 - 2nd UNITED-SAIG International Conference, 23-24 May 2022, Putrajaya, Malaysia SP - 1 EP - 3 ER - TY - JOUR A1 - Abbas, Karim A1 - Balc, Nicolae A1 - Bremen, Sebastian A1 - Skupin, Marco T1 - Crystallization and aging behavior of polyetheretherketone PEEK within rapid tooling and rubber molding JF - Journal of Manufacturing and Materials Processing N2 - In times of short product life cycles, additive manufacturing and rapid tooling are important methods to make tool development and manufacturing more efficient. High-performance polymers are the key to mold production for prototypes and small series. However, the high temperatures during vulcanization injection molding cause thermal aging and can impair service life. The extent to which the thermal stress over the entire process chain stresses the material and whether it leads to irreversible material aging is evaluated. To this end, a mold made of PEEK is fabricated using fused filament fabrication and examined for its potential application. The mold is heated to 200 ◦C, filled with rubber, and cured. A differential scanning calorimetry analysis of each process step illustrates the crystallization behavior and first indicates the material resistance. It shows distinct cold crystallization regions at a build chamber temperature of 90 ◦C. At an ambient temperature above Tg, crystallization of 30% is achieved, and cold crystallization no longer occurs. Additional tensile tests show a decrease in tensile strength after ten days of thermal aging. The steady decrease in recrystallization temperature indicates degradation of the additives. However, the tensile tests reveal steady embrittlement of the material due to increasing crosslinking. KW - additive manufacturing KW - fused filament fabrication KW - crystallization KW - polyetheretherketone KW - rapid tooling Y1 - 2022 U6 - https://doi.org/10.3390/jmmp6050093 SN - 2504-4494 N1 - The article belongs to the Special Issue Advances in Injection Molding: Process, Materials and Applications VL - 6 IS - 5 SP - 1 EP - 12 PB - MDPI CY - Basel ER -