TY - JOUR A1 - Al-Yasiri, Zainab Riyadh Shaker A1 - Mutashar, Hayder Majid A1 - Gürlebeck, Klaus A1 - Lahmer, Tom ED - Shafiullah, GM T1 - Damage Sensitive Signals for the Assessment of the Conditions of Wind Turbine Rotor Blades Using Electromagnetic Waves JF - Infrastructures N2 - One of the most important renewable energy technologies used nowadays are wind power turbines. In this paper, we are interested in identifying the operating status of wind turbines, especially rotor blades, by means of multiphysical models. It is a state-of-the-art technology to test mechanical structures with ultrasonic-based methods. However, due to the density and the required high resolution, the testing is performed with high-frequency waves, which cannot penetrate the structure in depth. Therefore, there is a need to adopt techniques in the fields of multiphysical model-based inversion schemes or data-driven structural health monitoring. Before investing effort in the development of such approaches, further insights and approaches are necessary to make the techniques applicable to structures such as wind power plants (blades). Among the expected developments, further accelerations of the so-called “forward codes” for a more efficient implementation of the wave equation could be envisaged. Here, we employ electromagnetic waves for the early detection of cracks. Because in many practical situations, it is not possible to apply techniques from tomography (characterized by multiple sources and sensor pairs), we focus here on the question of whether the existence of cracks can be determined by using only one source for the sent waves. KW - Windkraftwerk KW - Rotorblatt KW - Elektrostatische Welle KW - MATLAB KW - wind turbine rotor blades KW - electromagnetic waves KW - crack detection KW - Empire XPU 8.01 KW - Matlab KW - OA-Publikationsfonds2022 Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220831-47093 UR - https://www.mdpi.com/2412-3811/7/8/104 VL - 2022 IS - Volume 7, Issue 8 (August 2022), article 104 PB - MDPI CY - Basel ER - TY - JOUR A1 - Roskamm, Nikolai A1 - Vollmer, Lisa T1 - Was ist Stadt? Was ist Kritik? Einführung in die Debatte zum Jubiläumsheft von sub\urban JF - sub\urban. zeitschrift für kritische stadtforschung N2 - Im Heft zum zehnjährigen Jubiläum von sub\urban mit dem Themenschwerpunkt „sub\x: Verortungen, Entortungen" veröffentlichen wir eine Debatte, die von den bisherigen in unserer Zeitschrift in dieser Rubrik geführten textlichen Diskussionen abweicht. Im Vorfeld der Planungen für unsere Jubiläumsausgabe haben wir die aktuellen Mitglieder unseres wissenschaftlichen Beirats darum gebeten, zwei grundlegende Fragen von kritischer Stadtforschung in kurzen Beiträgen zu diskutieren: Was ist Stadt? Was ist Kritik? KW - Stadt KW - Stadtforschung KW - Kritik KW - Theorie KW - kritische Stadtforschung KW - Debatte KW - Stadtbegriff KW - Kritikbegriff KW - OA-Publikationsfonds2022 Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220811-46847 UR - https://zeitschrift-suburban.de/sys/index.php/suburban/article/view/798 IS - Band 10, Nr. 1, SP - 127 EP - 130 PB - Sub\urban e.V. CY - Leipzig ER - TY - JOUR A1 - Welch Guerra, Max T1 - Fach, Gesellschaft und Wissenschaft. Beitrag zur Debatte „Was ist Stadt? Was ist Kritik?“ JF - sub\urban. zeitschrift für kritische stadtforschung N2 - Der Aufruf, die Begriffe Stadt und Kritik in das Zentrum einer Debatte zu stellen, bietet die große Chance, uns weit über begriffliche Klärungen unseres gemeinsamen Arbeitsgegenstands hinaus – die ja auch für sich selbst sehr fruchtbar sein können – über die Funktion zu verständigen, die wir in der Gesellschaft ausüben, wenn wir räumliche Planung praktizieren, erforschen und lehren. Da in der Bundesrepublik nicht nur ein großer Bedarf, sondern auch eine beträchtliche Nachfrage nach öffentlicher Planung besteht und die planungsbezogenen Wissenschaften sich eines insgesamt stabilen institutionellen Standes erfreuen, laufen wir Gefahr, die gesellschaftspolitische Legitimation von Berufsfeld und Wissenschaft zu vernachlässigen, sie als gegeben zu behandeln. Wir müssen uns ja kaum rechtfertigen. KW - Stadt KW - Kritik KW - Wissenschaftskritik KW - Kritikbegriff KW - Herrschaftskritik KW - Alltagskritik KW - OA-Publikationsfonds2022 Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220810-46855 UR - https://zeitschrift-suburban.de/sys/index.php/suburban/article/view/779 VL - 2022 IS - Band 10, Nr. 1 SP - 188 EP - 190 PB - Sub\urban e.V. CY - Leipzig ER - TY - BOOK A1 - Bee, Julia A1 - Bergermann, Ulrike A1 - Keck, Linda A1 - Sander, Sarah A1 - Schwaab, Herbert A1 - Stauff, Markus A1 - Wagner, Franzi T1 - Fahrradutopien. Medien, Ästhetiken und Aktivismus N2 - Das Fahrrad ist ein Medium sozialer Veränderung. Seine vielfältigen utopischen Potenziale ergeben sich nicht zuletzt aus seinen ebenso vielfältigen und häufig übersehenen medialen Qualitäten: Es vermittelt, es verbindet, es übersetzt; es modifiziert Wahrnehmung und Organisation von Raum und Zeit, von Körpern und von Sozialität. Umgekehrt kann auch das medienwissenschaftliche Denken fahrradmedial verändert werden. Das Fahrrad ist nicht nur Medium des sozialen und ökologischen Wandels: Radfahren eröffnet Perspektiven, verändert Räume, lässt neue Relationen entstehen und teilt Handlungsmacht neu auf. Fahrradutopien denkt vom Fahrrad aus und ergänzt dabei bestehende Ansätze zur Mobilitätsforschung um medienkulturwissenschaftliche Perspektiven. Die Beiträge verbinden Medienwissenschaften und Forschungen zu Fahrradaktivismus mit der Liebe zum Radfahren. Fokussiert werden Fahrradfilme und -vlogs, Verkehr und Infrastrukturen, Virtuelle Realität und Fahrrad, Fahrradkollektive und Fahrradfeminismus. KW - Fahrrad KW - Mobilität KW - Medienwissenschaft KW - Aktivismus KW - Fahrradfahren KW - Medienkultur KW - Mobilitätsforschung KW - Fahrradaktivismus KW - OA-Publikationsfonds2022 Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220809-46743 UR - https://meson.press/books/fahrradutopien/ SN - 978-3-95796-196-9 PB - meson press CY - Lüneburg ER - TY - JOUR A1 - Hanna, John T1 - Computational Modelling for the Effects of Capsular Clustering on Fracture of Encapsulation-Based Self-Healing Concrete Using XFEM and Cohesive Surface Technique JF - Applied Sciences N2 - The fracture of microcapsules is an important issue to release the healing agent for healing the cracks in encapsulation-based self-healing concrete. The capsular clustering generated from the concrete mixing process is considered one of the critical factors in the fracture mechanism. Since there is a lack of studies in the literature regarding this issue, the design of self-healing concrete cannot be made without an appropriate modelling strategy. In this paper, the effects of microcapsule size and clustering on the fractured microcapsules are studied computationally. A simple 2D computational modelling approach is developed based on the eXtended Finite Element Method (XFEM) and cohesive surface technique. The proposed model shows that the microcapsule size and clustering have significant roles in governing the load-carrying capacity and the crack propagation pattern and determines whether the microcapsule will be fractured or debonded from the concrete matrix. The higher the microcapsule circumferential contact length, the higher the load-carrying capacity. When it is lower than 25% of the microcapsule circumference, it will result in a greater possibility for the debonding of the microcapsule from the concrete. The greater the core/shell ratio (smaller shell thickness), the greater the likelihood of microcapsules being fractured. KW - Beton KW - Mikrokapsel KW - Rissausbreitung KW - Tragfähigkeit KW - self-healing concrete KW - microcapsule KW - capsular clustering KW - circumferential contact length KW - OA-Publikationsfonds2022 Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220721-46717 UR - https://www.mdpi.com/2076-3417/12/10/5112 VL - 2022 IS - Volume 12, issue 10, article 5112 SP - 1 EP - 17 PB - MDPI CY - Basel ER - TY - JOUR A1 - Gürlebeck, Klaus A1 - Legatiuk, Dmitrii A1 - Webber, Kemmar T1 - Operator Calculus Approach to Comparison of Elasticity Models for Modelling of Masonry Structures JF - Mathematics N2 - The solution of any engineering problem starts with a modelling process aimed at formulating a mathematical model, which must describe the problem under consideration with sufficient precision. Because of heterogeneity of modern engineering applications, mathematical modelling scatters nowadays from incredibly precise micro- and even nano-modelling of materials to macro-modelling, which is more appropriate for practical engineering computations. In the field of masonry structures, a macro-model of the material can be constructed based on various elasticity theories, such as classical elasticity, micropolar elasticity and Cosserat elasticity. Evidently, a different macro-behaviour is expected depending on the specific theory used in the background. Although there have been several theoretical studies of different elasticity theories in recent years, there is still a lack of understanding of how modelling assumptions of different elasticity theories influence the modelling results of masonry structures. Therefore, a rigorous approach to comparison of different three-dimensional elasticity models based on quaternionic operator calculus is proposed in this paper. In this way, three elasticity models are described and spatial boundary value problems for these models are discussed. In particular, explicit representation formulae for their solutions are constructed. After that, by using these representation formulae, explicit estimates for the solutions obtained by different elasticity theories are obtained. Finally, several numerical examples are presented, which indicate a practical difference in the solutions. KW - Mauerwerk KW - Elastizitätstheorie KW - Mathematische Modellierung KW - quaternionic analysis KW - mathematical modelling KW - operator calculus KW - model comparison KW - micropolar elasticity KW - OA-Publikationsfonds2022 Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220721-46726 UR - https://www.mdpi.com/2227-7390/10/10/1670 VL - 2022 IS - Volume 10, issue 10, article 1670 SP - 1 EP - 22 PB - MDPI CY - Basel ER - TY - JOUR A1 - Vollmer, Lisa T1 - Aber das sind doch die Guten – oder? Wohnungsgenossenschaften in Hamburg. Rezension zu Jo-scha Metzger (2021): Genossenschaften und die Wohnungsfrage. Konflikte im Feld der Sozialen Wohnungswirtschaft. Münster: Westfälisches Dampfboot JF - sub\urban. zeitschrift für kritische stadtforschung N2 - Warum werden in aktuellen Diskussionen Wohnungsgenossenschaften immer wieder als zentrale Akteure einer gemeinwohlorientierten Wohnraumversorgung benannt – obwohl sie kaum zur Schaffung neuen bezahlbaren Wohnraums beitragen? Warum wehrt sich die Mehrzahl der Wohnungsgenossenschaften mit Händen und Füßen gegen die Wiedereinführung eines Gesetzes zur Wohnungsgemeinnützigkeit, obwohl es doch gerade dieses Gesetz war, dass sie im 20. Jahrhundert zu im internationalen Vergleich großen Unternehmen wachsen ließ? Sind Wohnungsgenossenschaften nun klientilistische, wenig demokratische und nur halb dekommodifizierte Marktteilnehmer oder wichtiger Teil der Wohnungsversorgung der unteren Mittelschicht? Wer Antworten auf diese und andere Fragen sucht und Differenziertheit in ihrer Beantwortung aushält, lese Joscha Metzers Dissertation „Genossenschaften und die Wohnungsfrage. KW - Gentrifizierung KW - Wohnungsforschung KW - Genossenschaften KW - OA-Publikationsfonds2022 Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220713-46691 UR - https://zeitschrift-suburban.de/sys/index.php/suburban/article/view/795 VL - 2022 IS - Band 10, Nr. 1 SP - 261 EP - 267 PB - sub\urban e. V. CY - Berlin ER - TY - JOUR A1 - Söbke, Heinrich A1 - Lück, Andrea T1 - Framing Algorithm-Driven Development of Sets of Objectives Using Elementary Interactions JF - Applied System Innovation N2 - Multi-criteria decision analysis (MCDA) is an established methodology to support the decision-making of multi-objective problems. For conducting an MCDA, in most cases, a set of objectives (SOO) is required, which consists of a hierarchical structure comprised of objectives, criteria, and indicators. The development of an SOO is usually based on moderated development processes requiring high organizational and cognitive effort from all stakeholders involved. This article proposes elementary interactions as a key paradigm of an algorithm-driven development process for an SOO that requires little moderation efforts. Elementary interactions are self-contained information requests that may be answered with little cognitive effort. The pairwise comparison of elements in the well-known analytical hierarchical process (AHP) is an example of an elementary interaction. Each elementary interaction in the development process presented contributes to the stepwise development of an SOO. Based on the hypothesis that an SOO may be developed exclusively using elementary interactions (EIs), a concept for a multi-user platform is proposed. Essential components of the platform are a Model Aggregator, an Elementary Interaction Stream Generator, a Participant Manager, and a Discussion Forum. While the latter component serves the professional exchange of the participants, the first three components are intended to be automatable by algorithms. The platform concept proposed has been evaluated partly in an explorative validation study demonstrating the general functionality of the algorithms outlined. In summary, the platform concept suggested demonstrates the potential to ease SOO development processes as the platform concept does not restrict the application domain; it is intended to work with little administration moderation efforts, and it supports the further development of an existing SOO in the event of changes in external conditions. The algorithm-driven development of SOOs proposed in this article may ease the development of MCDA applications and, thus, may have a positive effect on the spread of MCDA applications. KW - Multikriteria-Entscheidung KW - Multikriterielle Entscheidungsanalyse KW - multi-criteria decision analysis; KW - set of objectives KW - crowdsourcing KW - platform KW - elementary interaction KW - OA-Publikationsfonds2022 Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220713-46624 UR - https://www.mdpi.com/2571-5577/5/3/49 VL - 2022 IS - Volume 5, issue 3, article 49 SP - 1 EP - 20 PB - MDPI CY - Basel ER - TY - JOUR A1 - Taraben, Jakob A1 - Morgenthal, Guido T1 - Integration and Comparison Methods for Multitemporal Image-Based 2D Annotations in Linked 3D Building Documentation JF - Remote Sensing N2 - Data acquisition systems and methods to capture high-resolution images or reconstruct 3D point clouds of existing structures are an effective way to document their as-is condition. These methods enable a detailed analysis of building surfaces, providing precise 3D representations. However, for the condition assessment and documentation, damages are mainly annotated in 2D representations, such as images, orthophotos, or technical drawings, which do not allow for the application of a 3D workflow or automated comparisons of multitemporal datasets. In the available software for building heritage data management and analysis, a wide range of annotation and evaluation functions are available, but they also lack integrated post-processing methods and systematic workflows. The article presents novel methods developed to facilitate such automated 3D workflows and validates them on a small historic church building in Thuringia, Germany. Post-processing steps using photogrammetric 3D reconstruction data along with imagery were implemented, which show the possibilities of integrating 2D annotations into 3D documentations. Further, the application of voxel-based methods on the dataset enables the evaluation of geometrical changes of multitemporal annotations in different states and the assignment to elements of scans or building models. The proposed workflow also highlights the potential of these methods for condition assessment and planning of restoration work, as well as the possibility to represent the analysis results in standardised building model formats. KW - Bauwesen KW - Punktwolke KW - Denkmalpflege KW - OA-Publikationsfonds2022 Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220513-46488 UR - https://www.mdpi.com/2072-4292/14/9/2286 VL - 2022 IS - Volume 14, issue 9, article 2286 SP - 1 EP - 20 PB - MDPI CY - Basel ER - TY - JOUR A1 - Alsaad, Hayder A1 - Hartmann, Maria A1 - Hilbel, Rebecca A1 - Völker, Conrad T1 - ENVI-met validation data accompanied with simulation data of the impact of facade greening on the urban microclimate JF - Data in Brief N2 - This dataset consists mainly of two subsets. The first subset includes measurements and simulation data conducted to validate the simulation tool ENVI-met. The measurements were conducted at the campus of the Bauhaus-University Weimar in Weimar, Germany and consisted of recording exterior air temperature, globe temperature, relative humidity, and wind velocity at 1.5 m at four points on four different days. After the measurements, the geometry of the campus was modelled and meshed; the simulations were conducted using the weather data of the measurements days with the aim of investigating the accuracy of the model. The second data subset consists of ENVI-met simulation data of the potential of facade greening in improving the outdoor environment and the indoor air temperature during heatwaves in Central European cities. The data consist of the boundary conditions and the simulation output of two simulation models: with and without facade greening. The geometry of the models corresponded to a residential buildings district in Stuttgart, Germany. The simulation output consisted of exterior air temperature, mean radiant temperature, relative humidity, and wind velocity at 12 different probe points in the model in addition to the indoor air temperature of an exemplary building. The dataset presents both vertical profiles of the probed parameters as well as the time series output of the five-day simulation duration. Both data subsets correspond to the investigations presented in the co-submitted article [1]. KW - Messung KW - Measurements KW - Simulations KW - ENVI-met KW - Living wall KW - Green facade KW - Simulation KW - OA-Publikationsfonds2022 Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220511-46455 UR - https://www.sciencedirect.com/science/article/pii/S2352340922004048#! VL - 2022 IS - Volume 42, article 108200 SP - 1 EP - 13 PB - Elsevier CY - Amsterdam ER -