@phdthesis{Moosbrugger, author = {Moosbrugger, Jennifer}, title = {Design Intelligence - Human-Centered-Design for the development of industrial AI/ML agents}, doi = {10.25643/bauhaus-universitaet.6409}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20230719-64098}, school = {Bauhaus-Universit{\"a}t Weimar}, pages = {201}, abstract = {This study deals with design for AI/ML systems, more precisely in the industrial AI context based on case studies from the factory automation field. It therefore touches on core concepts from Human-Centered-Design (HCD), User Experience (UX) and Human Computer Interaction (HCI) on one hand, as well as concepts from Artificial Intelligence (AI), Machine Learning (ML) and the impact of technology on the other. The case studies the research is based on are within the industrial AI domain. However, the final outcomes, the findings, solutions, artifacts and so forth, should be transferable to a wider spectrum of domains. The study's aim is to examine the role of designers in the age of AI and the factors which are relevant, based on the hypothesis that current AI/ML development lacks the human perspective, which means that there are pitfalls and challenges that design can help resolve. The initial literature review revealed that AI/ML are perceived as a new design material that calls for a new design paradigm. Additional research based on qualitative case study research was conducted to gain an overview of the relevant issues and challenges. From this, 17 themes emerged, which together with explorative expert interviews and a structured literature review, were further analyzed to produce the relevant HCD, UX and HCI themes. It became clear that designers need new processes, methods, and tools in the age of AI/ML in combination with not only design, but also data science and business expertise, which is why the proposed solution in this PhD features process modules for design, data science and business collaboration. There are seven process modules and their related activities and dependencies that serve as guidelines for practitioners who want to design intelligence. A unified framework for collecting use case exemplars was created, based on a workshop with different practitioners and researchers from the area of AI/ML to support and enrich the process modules with concrete projects examples.}, subject = {K{\"u}nstliche Intelligenz}, language = {en} } @techreport{Zanders, type = {Working Paper}, author = {Zanders, Theresa}, title = {Teilhabe an Gesundheitsversorgung von aufenthaltsrechtlich illegalisierten Menschen in Deutschland}, doi = {10.25643/bauhaus-universitaet.6396}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20230530-63968}, pages = {25}, abstract = {Die Gesundheitsversorgung in Deutschland ist seit den Bismarckschen Sozialreformen ein zunehmend institutionalisierter Teil der staatlichen Daseinsvorsorge im wohlfahrtsstaatlichen Gef{\"u}ge. Institutionalisiert ist die Gesundheitsversorgung in korporatistischer Logik, das heißt in kooperativen Beziehungen zum privatwirtschaftlichen und zivilgesellschaftlichen Sektor und mit Befugnissen der Selbstverwaltung. Zudem fußt das Gesundheitssystem auf einem Versicherungssystem mit lohnabh{\"a}ngigen Abgaben. Institutionalisiert ist die staatliche Daseinsvorsorge jedoch auch in seinen Ausschl{\"u}ssen. So werden Menschen ohne B{\"u}rgerrechte von vielen sozialen Rechten, wie von der Gesundheitsversorgung, ausgeschlossen, obwohl dieser Ausschluss im Widerspruch zu anderen konstitutiven Elementen des Nationalstaats steht. In diesem Working Paper werden die grundlegende Strukturen des deutschen Gesundheitssystems und darin innewohnende Funktionslogiken der Produktion von Teilhabe dargestellt. Abschließend werden in Anlehnung an Kronauer die verschiedenen Dimensionen von Teilhabe an Gesundheitsversorgung in ihrer Produktions- und Ausschlusslogik im Wohlfahrtsregime dargelegt dabei auf die Gruppe der aufenthaltsrechtlich Illegalisierten fokussiert, denen gesellschaftliche Teilhabe in vielen Lebensbereichen, wie auch stark im Gesundheitsbereich, untersagt wird. Gleichzeitig soll dargestellt werden, wie zivilgesellschaftliche Akteur*innen auch gegen staatliche Vorgaben oder Anreize, Teilhabe (wieder-)herstellen.}, subject = {Gesundheit}, language = {de} } @techreport{Raab, type = {Working Paper}, author = {Raab, Susanna}, title = {Ern{\"a}hrungsgerechtigkeit im deutschen Wohlfahrtsregime. Teilhabe und Ausschl{\"u}sse}, doi = {10.25643/bauhaus-universitaet.6395}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20230530-63952}, pages = {25}, abstract = {Ern{\"a}hrung bestimmt unser t{\"a}gliches Leben. Sie erf{\"u}llt in erster Linie die physiologische Notwendigkeit unseren K{\"o}rper am Leben zu halten und ist gleichzeitig Alltagspraxis, durch welche gesamtgesellschaftliche Strukturen sichtbar werden. Innerhalb dieser Alltagspraxen erf{\"u}llt Ern{\"a}hrung vor allem eine wichtige Funktion in der Herstellung gesellschaftlicher Teilhabe oder kann strukturelle Ausschl{\"u}sse und soziale Ungleichheit bedingen. Dem Wohlfahrtsregime kommt somit eine wichtige Aufgabe in der Grundversorgung der Bev{\"o}lkerung zu und muss innerhalb der Daseinsvorsorge auf Ausschl{\"u}sse von ern{\"a}hrungsbezogener Teilhabe einzelner Bev{\"o}lkerungsschichten eingehen und sozialer Ungleichheit entgegenwirken. In diesem Working Paper soll der Fragestellung nachgegangen werden, inwiefern Teilhabe bzw. strukturelle Ausschl{\"u}sse von Ern{\"a}hrung innerhalb des bundesdeutschen Wohlfahrtsregimes hergestellt werden und durch welche politischen Praktiken und Forderungen aus der Zivilgesellschaft bzw. sozialen Bewegungen ern{\"a}hrungsvermittelte Teilhabe (wieder) hergestellt wird.}, subject = {Ern{\"a}hrung}, language = {de} } @misc{OPUS4-6372, title = {Programm gemeinn{\"u}tzige Liegenschaften. Strategie zur F{\"o}rderung der {\"o}ffentlich-zivilgesellschaftlichen Zusammenarbeit}, organization = {Stadt Barcelona / Referat B{\"u}rger*innenrechte und Partizipation}, doi = {10.25643/bauhaus-universitaet.6372}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20230523-63724}, pages = {23}, abstract = {St{\"a}dten kam bei demokratischen Innovationsprozessen immer eine zentrale Rolle zu. Die {\"o}ffentlichen Verwaltungen der großen St{\"a}dte stellten Regeln f{\"u}r die Einf{\"u}hrung und Ausweitung der b{\"u}rgerschaftlichen Partizipation auf und reagierten damit auf Erfahrungen und Forderungen, die von der sch{\"o}pferischen politischen Kraft der sozialen und urbanen Bewegungen getragen wurden. Die Geschichte Barcelonas ist daf{\"u}r ein typisches Beispiel. Dank dieser sozialen Errungenschaften k{\"o}nnen wir von einer Reihe von G{\"u}tern und Dienstleistungen profitieren, die lokale Wohlfahrtssysteme ausmachen. Die Stadtverwal-tungen {\"u}bernehmen die Aufgabe, Ressourcen und Dienstleistungen bereitzustellen, die nicht nur mit Wohlfahrt und Gesundheit in Verbindung stehen, sondern auch mit der Sorge um Umfeld und Umwelt, mit der F{\"o}rderung von Maßnahmen in Bereichen wie Bildung, Kultur, Kunst oder Sport sowie mit der Dynamisierung von Wirtschaft und Gesellschaft. Ob zust{\"a}ndig oder nicht, die Kommunen m{\"u}ssen auf die Forderungen der B{\"u}rger*innen reagieren, sind sie doch die Verwaltungen, die den allt{\"a}glichen Problemen und Bed{\"u}rfnissen am n{\"a}chsten stehen. Daher liegt es weniger im Belieben der Stadtverwaltungen, ob sie notwendige Innova¬tionen anstoßen, sondern diese sind vielmehr Teil ihres Aufgabenbereichs. Um den Bed{\"u}rfnissen der B{\"u}rger*innen seitens der {\"o}ffentlichen Verwaltung gerecht zu werden, kam in den meisten F{\"a}llen eine von zwei Methoden zur Anwendung: die direkte Verwaltung durch die Beh{\"o}rden oder die indirekte Verwaltung mit dem privaten Sektor. Mit dem Anbruch einer neuen Zeit, in der alternative Methoden an Bedeutung gewonnen haben, w{\"a}chst das Interesse an Modellen {\"o}ffentlich-zivilgesellschaftlicher Zusammenarbeit. Hauptziel dieser Modelle ist es, Verwaltungen und B{\"u}rgerschaft eine Zusammenarbeit im gemeinsamen und allgemeinen Interesse zu erm{\"o}glichen, indem Projekte unterst{\"u}tzt werden, die Zugang, N{\"a}he und Partizipation in sich vereinen. Vor diesem Hintergrund bietet die Verwaltung {\"o}ffent¬licher Ressourcen M{\"o}glichkeiten zur Entwicklung neuer Formen kollektiver Intelligenz, mit ge¬meinsamer Verantwortung und Synergie zwischen Institution und B{\"u}rgerschaft, sodass die St{\"a}dte zu wahrhaft kooperativen Plattformen f{\"u}r {\"o}ffentliche Innovationen werden.}, subject = {Gemeinwohl}, language = {de} } @article{KraazKoopWunschetal., author = {Kraaz, Luise and Koop, Maria and Wunsch, Maximilian and Plank-Wiedenbeck, Uwe}, title = {The Scaling Potential of Experimental Knowledge in the Case of the Bauhaus.MobilityLab, Erfurt (Germany)}, series = {Urban Planning}, volume = {2022}, journal = {Urban Planning}, number = {Volume 7, Issue 3}, doi = {10.17645/up.v7i3.5329}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20230509-63633}, pages = {274 -- 284}, abstract = {Real-world labs hold the potential to catalyse rapid urban transformations through real-world experimentation. Characterised by a rather radical, responsive, and location-specific nature, real-world labs face constraints in the scaling of experimental knowledge. To make a significant contribution to urban transformation, the produced knowledge must go beyond the level of a building, street, or small district where real-world experiments are conducted. Thus, a conflict arises between experimental boundaries and the stimulation of broader implications. The challenges of scaling experimental knowledge have been recognised as a problem, but remain largely unexplained. Based on this, the article will discuss the applicability of the "typology of amplification processes" by Lam et al. (2020) to explore and evaluate the potential of scaling experimental knowledge from real-world labs. The application of the typology is exemplified in the case of the Bauhaus.MobilityLab. The Bauhaus.MobilityLab takes a unique approach by testing and developing cross-sectoral mobility, energy, and logistics solutions with a distinct focus on scaling knowledge and innovation. For this case study, different qualitative research techniques are combined according to "within-method triangulation" and synthesised in a strengths, weaknesses, opportunities, and threats (SWOT) analysis. The analysis of the Bauhaus.MobilityLab proves that the "typology of amplification processes" is useful as a systematic approach to identifying and evaluating the potential of scaling experimental knowledge.}, subject = {Stadtplanung}, language = {en} } @phdthesis{Drescher, author = {Drescher, Marcel}, title = {Open Innovation in KMU - Eine empirische Analyse der offenen Innovationsaktivit{\"a}ten im Kontext der Entrepreneurial Orientation}, doi = {10.25643/bauhaus-universitaet.4946}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20230314-49463}, school = {Bauhaus-Universit{\"a}t Weimar}, pages = {211}, abstract = {Open Innovation in kleinen und mittleren Unternehmen (KMU) hat sich stark ausdifferenziert. Dabei zeigt die Empirie, dass KMU unterschiedliche Wege in der offenen Entwicklung von Innovationen begehen. Um die bestehende Literatur zu erweitern, wurden mit dieser Dissertation die Ziele verfolgt 1) offene Innovationsaktivit{\"a}ten in KMU aus einer Prozessperspektive aufzudecken und genau zu beschreiben und 2) zu erkl{\"a}ren, warum sich die {\"O}ffnung von Innovationsprozessen in KMU unterscheidet. Daf{\"u}r wurde auf eine multiple Fallstudienanalyse zur{\"u}ckgegriffen. Untersuchungsobjekte waren kleine etablierte High-Tech Unternehmen aus den neuen Bundesl{\"a}ndern. Die Ergebnisse zeigen sechs Prozessmodelle der offenen Innovationsentwicklung, beschrieben als Open Innovation Muster. Deskriptionen dieser Muster unter Ber{\"u}cksichtigung von formenden Innovationsaktivit{\"a}ten, ausgetauschtem Wissen, beteiligten externen Akteuren und Gr{\"u}nden f{\"u}r und gegen Open Innovation vermitteln ein {\"u}ber den bisherigen Forschungsstand hinausgehendes Verst{\"a}ndnis von Open Innovation in KMU. Zudem zeigen die Ergebnisse, dass die Entrepreneurial Orientation erkl{\"a}rt, warum KMU bei der Ausgestaltung von offenen Innovationsprozessen unterschiedlich vorgehen. In der Dissertation wird detailliert dargelegt, welche Open Innovation Muster sich anhand der Entrepreneurial Orientation von KMU (nicht-entrepreneurial bis entrepreneurial) zeigen. Die Ergebnisse liefern sowohl wissenschaftliche Implikationen, als auch Handlungsempfehlungen f{\"u}r die Unternehmenspraxis.}, subject = {Open Innovation}, language = {de} } @article{AicherBoermelLondongetal., author = {Aicher, Andreas and B{\"o}rmel, Melanie and Londong, J{\"o}rg and Beier, Silvio}, title = {Vertical green system for gray water treatment: Analysis of the VertiKKA-module in a field test}, series = {Frontiers in Environmental Science}, volume = {2022}, journal = {Frontiers in Environmental Science}, number = {Volume 10 (2022), article 976005}, publisher = {Frontiers Media}, address = {Lausanne}, doi = {10.3389/fenvs.2022.976005}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20230124-48840}, pages = {1 -- 7}, abstract = {This work presents a modular Vertical Green System (VGS) for gray water treatment, developed at the Bauhaus-Universit{\"a}t Weimar. The concept was transformed into a field study with four modules built and tested with synthetic gray water. Each module set contains a small and larger module with the same treatment substrate and was fed hourly. A combination of lightweight structural material and biochar of agricultural residues and wood chips was used as the treatment substrate. In this article, we present the first 18 weeks of operation. Regarding the treatment efficiency, the parameters chemical oxygen demand (COD), total phosphorous (TP), ortho-phosphate (ortho-P), total bound nitrogen (TNb), ammonium nitrogen (NH4-N), and nitrate nitrogen (NO3-N) were analyzed and are presented in this work. The results of the modules with agricultural residues are promising. Up to 92\% COD reduction is stated in the data. The phosphate and nitrogen fractions are reduced significantly in these modules. By contrast, the modules with wood chips reduce only 67\% of the incoming COD and respectively less regarding phosphates and the nitrogen fraction.}, subject = {Grauwasser}, language = {en} } @article{Coenen, author = {Coenen, Ekkehard}, title = {Communicative Action, Objectifications, and the Triad of Violence}, series = {Human Studies}, volume = {2022}, journal = {Human Studies}, number = {45 (2022)}, publisher = {Springer Science + Business Media B.V}, address = {Dordrecht}, doi = {10.1007/s10746-022-09639-1}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20230124-48828}, pages = {447 -- 468}, abstract = {This article aims to develop a social theory of violence that emphasizes the role of the third party as well as the communication between the involved subjects. For this Teresa Koloma Beck's essay 'The Eye of the Beholder: Violence as a Social Process' is taken as a starting point, which adopts a social-constructivist perspective. On the one hand, the basic concepts and the benefits of this approach are presented. On the other hand, social-theoretical problems of this approach are revealed. These deficits are counteracted by expanding Koloma Beck's approach with a communicative-constructivist framework. Thus, the role of communicative action and the 'objectification of violence' is emphasized. These aspects impact the perception, judgement and (de-)legitimation of violence phenomena and the emergence of a 'knowledge of violence'. Communicative actions and objectifications form a key to understanding violent interactions and the link between the micro and macro levels. Finally, the methodological consequences for the research of violence and Communicative Constructivism are discussed. Furthermore, possible research fields are outlined, which open up by looking at communicative action and the objectifications within the 'triads of violence'.}, subject = {Gewalt}, language = {en} } @article{Stadler, author = {Stadler, Max}, title = {Gr{\"u}nderzeit. Hightech und Alternativen der Wissenschaft in West-Berlin}, series = {NTM Zeitschrift f{\"u}r Geschichte der Wissenschaften, Technik und Medizin}, volume = {2022}, journal = {NTM Zeitschrift f{\"u}r Geschichte der Wissenschaften, Technik und Medizin}, number = {30 (2022)}, publisher = {Basel}, address = {Birkh{\"a}user}, doi = {10.1007/s00048-022-00352-9}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20230124-48800}, pages = {599 -- 632}, abstract = {Zu den diversen Unternehmungen sozialbewegter „Gegenwissenschaft", die um 1980 auf der Bildfl{\"a}che der BRD erschienen, z{\"a}hlte der 1982 gegr{\"u}ndete Berliner Wissenschaftsladen e. V., kurz WILAB - eine Art „alternatives" Spin-off der Technischen Universit{\"a}t Berlin. Der vorliegende Beitrag situiert die Ausgr{\"u}ndung des „Ladens" im Kontext zeitgen{\"o}ssischer Fortschritte der (regionalen) Forschungs- und Technologiepolitik. Gezeigt wird, wie der deindustrialisierenden Inselstadt, qua „innovationspolitischer" Gegensteuerung, dabei sogar eine gewisse Vorreiterrolle zukam: {\"u}ber die Stadtgrenzen hinaus sichtbare Neuerungen wie die Gr{\"u}ndermesse BIG TECH oder das 1983 er{\"o}ffnete Berliner Innovations- und Gr{\"u}nderzentrum (BIG), der erste „Incubator" [sic] der BRD, etwa gingen auf das Konto der 1977/78 lancierten Technologie-Transferstelle der TU Berlin, TU-transfer. Anders gesagt: tendenziell bekam man es hier nun mit Verh{\"a}ltnissen zu tun, die immer weniger mit den Tr{\"a}umen einer „kritischen", nicht-fremdbestimmten (Gegen‑)Wissenschaft kompatibel waren. Latent kontr{\"a}r zur historiographischen Prominenz des wissenschaftskritischen Zeitgeists fristeten „alternativen" Zielsetzungen verpflichtete Unternehmungen wie „WILAB" ein relativ marginalisiertes Nischendasein. Dennoch wirft das am WILAB verfolgte, so gesehen wenig aussichtsreiche Anliegen, eine andere, n{\"a}mlich „humanere" Informationstechnologie in die Wege zu leiten, ein instruktives Licht auf die Aufbr{\"u}che „unternehmerischer" Wissenschaft in der BRD um 1980.}, subject = {Berlin }, language = {de} } @article{HahlbrockBraunHeideletal., author = {Hahlbrock, David and Braun, Michael and Heidel, Robin and Lemmen, Patrik and Boumann, Roland and Bruckmann, Tobias and Schramm, Dieter and Helm, Volker and Willmann, Jan}, title = {Cable Robotic 3D-printing: additive manufacturing on the construction site}, series = {Construction Robotics}, volume = {2022}, journal = {Construction Robotics}, publisher = {Springer International Publishing}, address = {Cham}, doi = {10.1007/s41693-022-00082-3}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20230124-48791}, pages = {1 -- 14}, abstract = {This paper outlines an important step in characterizing a novel field of robotic construction research where a cable-driven parallel robot is used to extrude cementitious material in three-dimensional space, and thus offering a comprehensive new approach to computational design and construction, and to robotic fabrication at larger scales. Developed by the Faculty of Art and Design at Bauhaus-University Weimar (Germany), the faculty of Architecture at the University of Applied Sciences Dortmund (Germany) and the Chair of Mechatronics at the University of Duisburg-Essen (Germany), this approach offers unique advantages over existing additive manufacturing methods: the system is easily transportable and scalable, it does not require additional formwork or scaffolding, and it offers digital integration and informational oversight across the entire design and building process. This paper considers 1) key research components of cable robotic 3D-printing (such as computational design, material exploration, and robotic control), and 2) the integration of these parameters into a unified design and building process. The demonstration of the approach at full-scale is of particular concern.}, subject = {Robotik}, language = {en} } @article{MoscosoKraus, author = {Moscoso, Caridad and Kraus, Matthias}, title = {On the Verification of Beams Subjected to Lateral Torsional Buckling by Simplified Plastic Structural Analysis}, series = {ce/papers}, volume = {2022}, journal = {ce/papers}, number = {Volume 5, Issue 4}, publisher = {Ernst \& Sohn}, address = {Berlin}, doi = {10.1002/cepa.1835}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20230124-48782}, pages = {914 -- 923}, abstract = {Plastic structural analysis may be applied without any difficulty and with little effort for structural member verifications with regard to lateral torsional buckling of doubly symmetric rolled I sections. Suchlike analyses can be performed based on the plastic zone theory, specifically using finite beam elements with seven degrees of freedom and 2nd order theory considering material nonlinearity. The existing Eurocode enables these approaches and the coming-up generation will provide corresponding regulations in EN 1993-1-14. The investigations allow the determination of computationally accurate limit loads, which are determined in the present paper for selected structural systems with different sets of parameters, such as length, steel grade and cross section types. The results are compared to approximations gained by more sophisticated FEM analyses (commercial software Ansys Workbench applying solid elements) for reasons of verification/validation. In this course, differences in the results of the numerical models are addressed and discussed. In addition, results are compared to resistances obtained by common design regulations based on reduction factors χlt including regulations of EN 1993-1-1 (including German National Annex) as well as prEN 1993-1-1: 2020-08 (proposed new Eurocode generation). Concluding, correlations of results and their advantages as well as disadvantages are discussed.}, subject = {Stahl}, language = {en} } @article{Morawski, author = {Morawski, Tommaso}, title = {La tavola e la mappa. Paradigmi per una metaforologia mediale dell'immaginazione cartografica in Kant}, series = {Philosophy Kitchen}, volume = {2022}, journal = {Philosophy Kitchen}, number = {17, II/2022}, publisher = {Universit{\`a} degli Studi di Torino}, address = {Turino}, doi = {10.13135/2385-1945/7191}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20230124-48766}, pages = {137 -- 152}, abstract = {Immanuel Kant's thought is a central historical and theoretical reference in Hans Blumenberg's metaphorological project. This is demonstrated by the fact that in the Paradigms the author outlines the concept of absolute metaphor by explicitly referring to \S59 of the Critique of the Power of Judgment and recognizing in the Kantian symbol a model for his own metaphorics. However, Kant's name also appears in the chapter on the metaphor of the "terra incognita" that not only did he theorize the presence of symbolic hypotyposis in our language [...] but also made extensive use of metaphors linked to "determinate historical experiences". In particular: geographical metaphors. In my essay, I would like to start from the analysis of Kant's geographical metaphors in order to try to rethink Blumenberg's archaeological method as an archaeology of media that grounds the study of metaphors in the materiality of communication and the combination of tools, agents and media.}, subject = {Kant, Immanuel}, language = {it} } @article{BuschowWellbrock, author = {Buschow, Christopher and Wellbrock, Christian-Mathias}, title = {"Spotify for News"? User Perception of Subscription-Based Content Platforms for News Media}, series = {Journalism and Media}, volume = {2022}, journal = {Journalism and Media}, number = {2023, 4}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/journalmedia4010001}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20230124-48740}, pages = {1 -- 15}, abstract = {Subscription-based news platforms (such as "Apple News+" or "Readly") that bundle content from different publishers into one comprehensive package and offer it to media users at a fixed monthly rate are a new way of accessing and consuming digital journalism. These services have received little attention in journalism studies, although they differ greatly from traditional media products and distribution channels. This article empirically investigates the perception of journalism platforms based on eight qualitative focus group discussions with 55 German news consumers. Results show that the central characteristics these platforms should fulfill in order to attract users are strikingly similar to the characteristics of media platforms from the music and video industries, in particular regarding price points, contract features, and modes of usage. Against this background, the potential and perspectives of a subscription-based news platform for journalism's societal role are discussed.}, subject = {Journalistik}, language = {en} } @phdthesis{Held, author = {Held, Tobias}, title = {Einblick: Gestalterische Potentiale und Perspektiven der Videotelefonie im Kontext von N{\"a}he und Distanz. Eine praxis-basierte, (re-)kontextualisierende und diskursanalytische Studie.}, doi = {10.25643/bauhaus-universitaet.4886}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20230111-48867}, school = {Bauhaus-Universit{\"a}t Weimar}, pages = {534}, abstract = {Inhaltlich besch{\"a}ftigt sich die Arbeit, die im Rahmen des Promotionsstudiengangs Kunst und Gestaltung an der Bauhaus-Universit{\"a}t entstand, mit der Erforschung sozio-interaktiver Potentiale der Videotelefonie im Kontext von N{\"a}he und Verbundenheit mit Fokus auf Eigenbild, Embodiment sowie den Rederechtswechsel. Die Videotelefonie als Kommunikationsform hat sich - und darauf deuten die Erfahrungen der Co- vid-19-Pandemie hin - im lebensweltlichen Alltag der Menschen etabliert und wird dort in naher Zukunft nicht mehr wegzudenken sein. Auf Basis ihrer M{\"o}glichkeiten und Errungenschaften ist es inzwischen Realit{\"a}t und Lebenswirklichkeit, dass die Kommunikation sowohl im privaten als auch im gesch{\"a}ftlichen Kontext mittels verschiedenster Kan{\"a}le stattfindet. Der Videotelefonie kommt hierbei als solche nicht nur eine tragende Funktion, sondern auch eine herausragende Rolle bei der vermeintlichen Reproduktion der Face-to-Face-Kommunikation im digitalen Raum zu und wird wie selbstverst{\"a}ndlich zum zwischenmenschlichen Austausch genutzt. Just an diesem Punkt kn{\"u}pft die Forschungsarbeit an. Zentral stand dabei das Vorhaben einer dezidierte Untersuchung des Forschungsgegenstandes Videotelefonie, sowohl aus Kultur- als auch Technikhistorischer, aber auch Medien-, Wahrnehmungs- wie Kommunikations- theoretischer Perspektive, indem analytische und ph{\"a}nosemiotische Perspektiven miteinander in Beziehung gesetzt werden (z.B. Wahrnehmungsbedingungen, Interaktionsmerkmale, realisierte Kommunikationsprozesse etc.). Damit verbundenes, w{\"u}nschenswertes Ziel war es, eine m{\"o}glichst zeitgem{\"a}ße wie relevante Forschungsfrage zu adressieren, die neben den kulturellen Technisierungs- und Mediatisierungstendenzen in institutionellen und privaten Milieus ebenfalls eine conditio sine qua non der pandemischen (Massen-)Kommunikation entwirft. Die Arbeit ist damit vor allem im Bereich des Produkt- und Interactiondesigns zu verorten. Dar{\"u}ber hinaus hatte sie das Ziel der Darlegung und Begr{\"u}ndung der Videotelefonie als eigenst{\"a}ndige Kommunikationsform, welche durch eigene, kommunikative Besonderheiten, die sich in ihrer jeweiligen Ingebrauchnahme sowie durch spezielle Wahrnehmungsbedingungen {\"a}ußern, und die die Videotelefonie als »Rederechtswechselmedium« avant la lettre konsolidieren, gekennzeichnet ist. Dabei sollte der Beweis erbracht werden, dass die Videotelefonie nicht als Schwundstufe einer Kommunikation Face-to-Face, sondern als ein eigenst{\"a}ndiges Mediatisierungs- und Kommunikationsereignis zu verstehen sei. Und eben nicht als eine beliebige - sich linear vom Telefon ausgehende - entwickelte Form der audio-visuellen Fernkommunikation darstellt, sondern die gestalterische (Bewegtbild-)Technizit{\"a}t ein eigenst{\"a}ndiges Funktionsmaß offeriert, welches wiederum ein innovatives Kommunikationsmilieu im Kontext einer Rederechtswechsel-Medialit{\"a}t stabilisiert.}, subject = {Videotelefonie}, language = {de} } @misc{PachecoAlvim, type = {Master Thesis}, author = {Pacheco Alvim, Sarah}, title = {Falsa Seringueira: Rubber Trees and the Materiality of the Unseen}, doi = {10.25643/bauhaus-universitaet.4846}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20230105-48467}, school = {Bauhaus-Universit{\"a}t Weimar}, pages = {128}, abstract = {The theme of this project is the colonial history of the natural rubber industry. It focuses on two species of tropical plants: Ficus elastica and Hevea brasiliensis. Geographically their native habitat is very distant from each other, but they connect by European influence through the exploitation of latex. The many forms and outcomes from this work manifest the attempt of the artist to create an association between a common household plant, the origin of its name, and the source of rubber. As a ghostly connective tissue, the latex surrounds reconstructed history, old prints, live plants, and drawings, accepting the material's capacity to both erase and preserve the past.}, subject = {Kautschuk}, language = {en} } @periodical{BognerKarpfWilleretal., author = {Bogner, Simone and Karpf, Michael and Willer, Stefan and Aquilar, Giorgia and Springer, J{\"o}rg and Euler-Rolle, Bernd and Sikiaridi, Elizabeth and Vogelaar, Frans and von Beckerath, Verena and Klei, Alexandra and Raheem, Oluwafunminiyi and Grundig, Ronny and Sezer, {\"O}zge and Kutkina, Anna and Manka, Inge and Hettchen, Karolina and J{\"u}ttner, Monique and Blunk, Julian}, title = {Praktiken des Erbens. Metaphern, Materialisierungen, Machtkonstellationen}, editor = {Bogner, Simone and Karpf, Michael and Meier, Hans-Rudolf}, publisher = {Bauhaus-Universit{\"a}tsverlag}, address = {Weinstraße-Ilmtal}, doi = {10.25643/bauhaus-universitaet.4702}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20220810-47025}, abstract = {Ausgehend von der Bemerkung des Philosophen Jacques Derrida, dass Erbe immer auch eine Aufgabe sei, widmet sich der dritte Band der Schriftenreihe des Graduiertenkollegs „Identit{\"a}t und Erbe" den sozialen und kulturellen Praktiken der Bezugnahme auf Vergangenheit(en) und Identit{\"a}t(en). Mit einem (kulturellen) Erbe soll und muss etwas getan werden, um es {\"u}berhaupt hervorzubringen. Es konstituiert sich erst im Akt des (Nicht-)Erbens, das heißt im Wechselverh{\"a}ltnis mit den mit und an ihm ausgef{\"u}hrten Praktiken. Gleichwohl erm{\"o}glicht erst deren Verbindung mit den materiellen {\"U}berresten und {\"U}berlieferungen des Erbes eine Aneignung oder Ablehnung der Vergangenheit sowie die Fort- und Umschreibung eines bereits bestehenden Erbes. Diese Vorg{\"a}nge sind nicht willk{\"u}rlicher Natur: Die M{\"o}glichkeiten zur Interpretation und Deutung werden durch die sozialen, politischen, kulturellen, {\"o}konomischen und technischen Bedingungen der Gegenwart sowie durch die Geschichte und Materialit{\"a}t des Erbes beschr{\"a}nkt, erweitert und gelenkt. Erbe und Erbeprozesse m{\"u}ssen deshalb notwendigerweise miteinander in Beziehung gesetzt werden. Mit Beitr{\"a}gen von Simone Bogner und Michael Karpf, Stefan Willer, Giorgia Aquilar, J{\"o}rg Springer, Bernd Euler-Rolle, Elizabeth Sikiaridi und Frans Vogelaar, Verena von Beckerath, Alexandra Klei, Oluwafunminiyi Raheem, Ronny Grundig, {\"O}zge Sezer, Anna Kutkina, Inge Manka, Karolina Hettchen und Monique J{\"u}ttner sowie Julian Blunk.}, subject = {Kulturerbe}, language = {de} } @phdthesis{Mueller, author = {M{\"u}ller, Matthias}, title = {Salt-frost Attack on Concrete - New Findings regarding the Damage Mechanism}, doi = {10.25643/bauhaus-universitaet.4868}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20230103-48681}, school = {Bauhaus-Universit{\"a}t Weimar}, abstract = {The reduction of the cement clinker content is an important prerequisite for the improvement of the CO2-footprint of concrete. Nevertheless, the durability of such concretes must be sufficient to guarantee a satisfactory service life of structures. Salt frost scaling resistance is a critical factor in this regard, as it is often diminished at increased clinker substitution rates. Furthermore, only insufficient long-term experience for such concretes exists. A high salt frost scaling resistance thus cannot be achieved by applying only descriptive criteria, such as the concrete composition. It is therefore to be expected, that in the long term a performance based service life prediction will replace the descriptive concept. To achieve the important goal of clinker reduction for concretes also in cold and temperate climates it is important to understand the underlying mechanisms for salt frost scaling. However, conflicting damage theories dominate the current State of the Art. It was consequently derived as the goal of this thesis to evaluate existing damage theories and to examine them experimentally. It was found that only two theories have the potential to describe the salt frost attack satisfactorily - the glue spall theory and the cryogenic suction theory. The glue spall theory attributes the surface scaling to the interaction of an external ice layer with the concrete surface. Only when moderate amounts of deicing salt are present in the test solution the resulting mechanical properties of the ice can cause scaling. However, the results in this thesis indicate that severe scaling also occurs at deicing salt levels, at which the ice is much too soft to damage concrete. Thus, the inability of the glue spall theory to account for all aspects of salt frost scaling was shown. The cryogenic suction theory is based on the eutectic behavior of salt solutions, which consist of two phases - water ice and liquid brine - between the freezing point and the eutectic temperature. The liquid brine acts as an additional moisture reservoir, which facilitates the growth of ice lenses in the surface layer of the concrete. The experiments in this thesis confirmed, that the ice formation in hardened cement paste increases due to the suction of brine at sub-zero temperatures. The extent of additional ice formation was influenced mainly by the porosity and by the chloride binding capacity of the hardened cement paste. Consequently, the cryogenic suction theory plausibly describes the actual generation of scaling, but it has to be expanded by some crucial aspects to represent the salt frost scaling attack completely. The most important aspect is the intensive saturation process, which is ascribed to the so-called micro ice lens pump. Therefore a combined damage theory was proposed, which considers multiple saturation processes. Important aspects of this combined theory were confirmed experimentally. As a result, the combined damage theory constitutes a good basis to understand the salt frost scaling attack on concrete on a fundamental level. Furthermore, a new approach was identified, to account for the reduced salt frost scaling resistance of concretes with reduced clinker content.}, subject = {Beton}, language = {en} } @periodical{BognerGourinovitchBaetal., author = {Bogner, Simone and Gourinovitch, Oxana and Ba, Claudia and Kibel, Jochen and Stapel, G{\"u}l{\c{s}}ah and Krajewsky, Georg and Fr{\"o}lich-Kulik, Maria and Masoud, Zoya and W{\"a}chter, Konstantin and H{\"a}ger, Benjamin and H{\"o}hne, Wolfram and Alberti, Sarah and Tr{\"o}tschel-Daniels, Bianka and Helas, Luise and Selitz, Lisa Marie and Torreiter, Laura}, title = {Instabile Konstruktionen. Interdisziplin{\"a}re Forschungen zu »Identit{\"a}t und Erbe«}, editor = {Bogner, Simone and Dolff-Bonek{\"a}mper, Gabi and Meier, Hans-Rudolf}, publisher = {Bauhaus-Universit{\"a}tsverlag}, address = {Ilmtal-Weinstraße}, doi = {10.25643/bauhaus-universitaet.4606}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20220315-46066}, pages = {264}, abstract = {Wer von Erbe im Zusammenhang mit Identit{\"a}t spricht, verspricht sich und Anderen »Kontinuit{\"a}t« und »Stabilit{\"a}t«. Das Versprechen h{\"a}lt indes nur so lange, wie sich Menschen auf die damit verbundenen Erz{\"a}hlungen einlassen. Da diese zunehmend hinterfragt werden und der Begriff »Identit{\"a}t« im politischen Raum zu einer umk{\"a}mpften Kategorie avanciert ist, werden auch die lange gehegten, gewohnten »Konstruktionen« instabil. Dies zeigt sich insbesondere in Momenten des Konflikts, der {\"u}bergriffigen Inanspruchnahme und des Verlusts. Der Titel »Instabile Konstruktionen« verweist zugleich auf die beiden Kernbereiche des Kollegs: einerseits auf Architektur und Denkmalpflege, in denen der Begriff Konstruktion sich auf bauliche Manifestationen bezieht, von denen eine gewisse Haltbarkeit und Dauerhaftigkeit erwartet wird und andererseits auf die Kultur- und Sozialwissenschaften, wo Konstruktion die soziale Herstellung symbolischer Sinnwelten meint. Ins Zentrum r{\"u}ckt so der Anspruch, die materielle Umwelt im Wechselverh{\"a}ltnis zu ihrer sozialen Gemachtheit zu verstehen.}, subject = {Identit{\"a}t}, language = {de} } @phdthesis{Mojahedin, author = {Mojahedin, Arvin}, title = {Analysis of Functionally Graded Porous Materials Using Deep Energy Method and Analytical Solution}, doi = {10.25643/bauhaus-universitaet.4867}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20221220-48674}, school = {Bauhaus-Universit{\"a}t Weimar}, abstract = {Porous materials are an emerging branch of engineering materials that are composed of two elements: One element is a solid (matrix), and the other element is either liquid or gas. Pores can be distributed within the solid matrix of porous materials with different shapes and sizes. In addition, porous materials are lightweight, and flexible, and have higher resistance to crack propagation and specific thermal, mechanical, and magnetic properties. These properties are necessary for manufacturing engineering structures such as beams and other engineering structures. These materials are widely used in solid mechanics and are considered a good replacement for classical materials by many researchers recently. Producing lightweight materials has been developed because of the possibility of exploiting the properties of these materials. Various types of porous material are generated naturally or artificially for a specific application such as bones and foams. Like functionally graded materials, pore distribution patterns can be uniform or non-uniform. Biot's theory is a well-developed theory to study the behavior of poroelastic materials which investigates the interaction between fluid and solid phases of a fluid-saturated porous medium. Functionally graded porous materials (FGPM) are widely used in modern industries, such as aerospace, automotive, and biomechanics. These advanced materials have some specific properties compared to materials with a classic structure. They are extremely light, while they have specific strength in mechanical and high-temperature environments. FGPMs are characterized by a gradual variation of material parameters over the volume. Although these materials can be made naturally, it is possible to design and manufacture them for a specific application. Therefore, many studies have been done to analyze the mechanical and thermal properties of FGPM structures, especially beams. Biot was the pioneer in formulating the linear elasticity and thermoelasticity equations of porous material. Since then, Biot's formulation has been developed in continuum mechanics which is named poroelasticity. There are obstacles to analyzing the behavior of these materials accurately like the shape of the pores, the distribution of pores in the material, and the behavior of the fluid (or gas) that saturated pores. Indeed, most of the engineering structures made of FGPM have nonlinear governing equations. Therefore, it is difficult to study engineering structures by solving these complicated equations. The main purpose of this dissertation is to analyze porous materials in engineering structures. For this purpose, the complex equations of porous materials have been simplified and applied to engineering problems so that the effect of all parameters of porous materials on the behavior of engineering structure has been investigated. The effect of important parameters of porous materials on beam behavior including pores compressibility, porosity distribution, thermal expansion of fluid within pores, the interaction of stresses between pores and material matrix due to temperature increase, effects of pore size, material thickness, and saturated pores with fluid and unsaturated conditions are investigated. Two methods, the deep energy method, and the exact solution have been used to reduce the problem hypotheses, increase accuracy, increase processing speed, and apply these in engineering structures. In both methods, they are analyzed nonlinear and complex equations of porous materials. To increase the accuracy of analysis and study of the effect of shear forces, Timoshenko and Reddy's beam theories have been used. Also, neural networks such as residual and fully connected networks are designed to have high accuracy and less processing time than other computational methods.}, subject = {Por{\"o}ser Stoff}, language = {en} } @phdthesis{Legatiuk, author = {Legatiuk, Anastasiia}, title = {Discrete potential and function theories on a rectangular lattice and their applications}, doi = {10.25643/bauhaus-universitaet.4865}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20221220-48654}, school = {Bauhaus-Universit{\"a}t Weimar}, abstract = {The growing complexity of modern engineering problems necessitates development of advanced numerical methods. In particular, methods working directly with discrete structures, and thus, representing exactly some important properties of the solution on a lattice and not just approximating the continuous properties, become more and more popular nowadays. Among others, discrete potential theory and discrete function theory provide a variety of methods, which are discrete counterparts of the classical continuous methods for solving boundary value problems. A lot of results related to the discrete potential and function theories have been presented in recent years. However, these results are related to the discrete theories constructed on square lattices, and, thus, limiting their practical applicability and potentially leading to higher computational costs while discretising realistic domains. This thesis presents an extension of the discrete potential theory and discrete function theory to rectangular lattices. As usual in the discrete theories, construction of discrete operators is strongly influenced by a definition of discrete geometric setting. For providing consistent constructions throughout the whole thesis, a detailed discussion on the discrete geometric setting is presented in the beginning. After that, the discrete fundamental solution of the discrete Laplace operator on a rectangular lattice, which is the core of the discrete potential theory, its numerical analysis, and practical calculations are presented. By using the discrete fundamental solution of the discrete Laplace operator on a rectangular lattice, the discrete potential theory is then constructed for interior and exterior settings. Several discrete interior and exterior boundary value problems are then solved. Moreover, discrete transmission problems are introduced and several numerical examples of these problems are discussed. Finally, a discrete fundamental solution of the discrete Cauchy-Riemann operator on a rectangular lattice is constructed, and basics of the discrete function theory on a rectangular lattice are provided. This work indicates that the discrete theories provide solution methods with very good numerical properties to tackle various boundary value problems, as well as transmission problems coupling interior and exterior problems. The results presented in this thesis provide a basis for further development of discrete theories on irregular lattices.}, subject = {Diskrete Funktionentheorie}, language = {en} } @misc{RaabMueller, author = {Raab, Susanna and M{\"u}ller, Hannah}, title = {LebensMittelPunkte schaffen in Kooperation! Ein Handlungsleitfaden f{\"u}r die Zusammenarbeit von bezirklicher Verwaltung und ern{\"a}hrungspolitischen Initiativen}, doi = {10.25643/bauhaus-universitaet.4734}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20221109-47347}, pages = {10}, abstract = {Zugang zu gesunder und nachhaltiger Ern{\"a}hrung ist in Berlin nicht f{\"u}r alle Menschen eine Selbstverst{\"a}ndlichkeit. Um Ern{\"a}hrung f{\"u}r alle gew{\"a}hrleisten zu k{\"o}nnen, braucht es einen Wandel des Ern{\"a}hrungssystems in Berlin, der eine {\"o}kologische, klima- und sozialgerechte Nahrungsproduktion und Verteilung f{\"u}r alle Menschen in der Stadt erm{\"o}glicht. Einen Beitrag um die Ern{\"a}hrung in der Stadt gerechter und nachhaltiger zu gestalten kann ein sogenannter LebensMittelPunkt (LMP) leisten. LebensMittelPunkte entstehen meist aus ehrenamtlichen Initiativen, k{\"o}nnen aber auch in Zusammenarbeit mit st{\"a}dtischen Verwaltungen etabliert werden. Eine Zusammenarbeit zwischen zivilgesellschaftlichen Organisationen und Verwaltungen kann dabei Potenziale und Ressourcen freisetzen. Dieser Leitfaden soll ern{\"a}hrungspolitischen Initiativen und Vereinen aus der Zivilgesellschaft sowie kommunalen oder bezirklichen Verwaltungen in Berlin - und dar{\"u}ber hinaus - Empfehlungen geben, wie ein LebensMittelPunkt in einer gemeinsamen Kooperation aufgebaut werden kann.}, subject = {Ern{\"a}hrung}, language = {de} } @article{AlaladeReichertKoehnetal., author = {Alalade, Muyiwa and Reichert, Ina and K{\"o}hn, Daniel and Wuttke, Frank and Lahmer, Tom}, title = {A Cyclic Multi-Stage Implementation of the Full-Waveform Inversion for the Identification of Anomalies in Dams}, series = {Infrastructures}, volume = {2022}, journal = {Infrastructures}, number = {Volume 7, issue 12, article 161}, editor = {Qu, Chunxu and Gao, Chunxu and Zhang, Rui and Jia, Ziguang and Li, Jiaxiang}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/infrastructures7120161}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20221201-48396}, pages = {19}, abstract = {For the safe and efficient operation of dams, frequent monitoring and maintenance are required. These are usually expensive, time consuming, and cumbersome. To alleviate these issues, we propose applying a wave-based scheme for the location and quantification of damages in dams. To obtain high-resolution "interpretable" images of the damaged regions, we drew inspiration from non-linear full-multigrid methods for inverse problems and applied a new cyclic multi-stage full-waveform inversion (FWI) scheme. Our approach is less susceptible to the stability issues faced by the standard FWI scheme when dealing with ill-posed problems. In this paper, we first selected an optimal acquisition setup and then applied synthetic data to demonstrate the capability of our approach in identifying a series of anomalies in dams by a mixture of reflection and transmission tomography. The results had sufficient robustness, showing the prospects of application in the field of non-destructive testing of dams.}, subject = {Damm}, language = {en} } @phdthesis{Hanna, author = {Hanna, John}, title = {Computational Fracture Modeling and Design of Encapsulation-Based Self-Healing Concrete Using XFEM and Cohesive Surface Technique}, doi = {10.25643/bauhaus-universitaet.4746}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20221124-47467}, school = {Bauhaus-Universit{\"a}t Weimar}, pages = {125}, abstract = {Encapsulation-based self-healing concrete (SHC) is the most promising technique for providing a self-healing mechanism to concrete. This is due to its capacity to heal fractures effectively without human interventions, extending the operational life and lowering maintenance costs. The healing mechanism is created by embedding capsules containing the healing agent inside the concrete. The healing agent will be released once the capsules are fractured and the healing occurs in the vicinity of the damaged part. The healing efficiency of the SHC is still not clear and depends on several factors; in the case of microcapsules SHC the fracture of microcapsules is the most important aspect to release the healing agents and hence heal the cracks. This study contributes to verifying the healing efficiency of SHC and the fracture mechanism of the microcapsules. Extended finite element method (XFEM) is a flexible, and powerful discrete crack method that allows crack propagation without the requirement for re-meshing and has been shown high accuracy for modeling fracture in concrete. In this thesis, a computational fracture modeling approach of Encapsulation-based SHC is proposed based on the XFEM and cohesive surface technique (CS) to study the healing efficiency and the potential of fracture and debonding of the microcapsules or the solidified healing agents from the concrete matrix as well. The concrete matrix and a microcapsule shell both are modeled by the XFEM and combined together by CS. The effects of the healed-crack length, the interfacial fracture properties, and microcapsule size on the load carrying capability and fracture pattern of the SHC have been studied. The obtained results are compared to those obtained from the zero thickness cohesive element approach to demonstrate the significant accuracy and the validity of the proposed simulation. The present fracture simulation is developed to study the influence of the capsular clustering on the fracture mechanism by varying the contact surface area of the CS between the microcapsule shell and the concrete matrix. The proposed fracture simulation is expanded to 3D simulations to validate the 2D computational simulations and to estimate the accuracy difference ratio between 2D and 3D simulations. In addition, a proposed design method is developed to design the size of the microcapsules consideration of a sufficient volume of healing agent to heal the expected crack width. This method is based on the configuration of the unit cell (UC), Representative Volume Element (RVE), Periodic Boundary Conditions (PBC), and associated them to the volume fraction (Vf) and the crack width as variables. The proposed microcapsule design is verified through computational fracture simulations.}, subject = {Beton}, language = {en} } @phdthesis{Jenabidehkordi, author = {Jenabidehkordi, Ali}, title = {An Efficient Adaptive PD Formulation for Complex Microstructures}, doi = {10.25643/bauhaus-universitaet.4742}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20221124-47422}, school = {Bauhaus-Universit{\"a}t Weimar}, pages = {118}, abstract = {The computational costs of newly developed numerical simulation play a critical role in their acceptance within both academic use and industrial employment. Normally, the refinement of a method in the area of interest reduces the computational cost. This is unfortunately not true for most nonlocal simulation, since refinement typically increases the size of the material point neighborhood. Reducing the discretization size while keep- ing the neighborhood size will often require extra consideration. Peridy- namic (PD) is a newly developed numerical method with nonlocal nature. Its straightforward integral form equation of motion allows simulating dy- namic problems without any extra consideration required. The formation of crack and its propagation is known as natural to peridynamic. This means that discontinuity is a result of the simulation and does not demand any post-processing. As with other nonlocal methods, PD is considered an expensive method. The refinement of the nodal spacing while keeping the neighborhood size (i.e., horizon radius) constant, emerges to several nonphysical phenomena. This research aims to reduce the peridynamic computational and imple- mentation costs. A novel refinement approach is introduced. The pro- posed approach takes advantage of the PD flexibility in choosing the shape of the horizon by introducing multiple domains (with no intersections) to the nodes of the refinement zone. It will be shown that no ghost forces will be created when changing the horizon sizes in both subdomains. The approach is applied to both bond-based and state-based peridynamic and verified for a simple wave propagation refinement problem illustrating the efficiency of the method. Further development of the method for higher dimensions proves to have a direct relationship with the mesh sensitivity of the PD. A method for solving the mesh sensitivity of the PD is intro- duced. The application of the method will be examined by solving a crack propagation problem similar to those reported in the literature. New software architecture is proposed considering both academic and in- dustrial use. The available simulation tools for employing PD will be collected, and their advantages and drawbacks will be addressed. The challenges of implementing any node base nonlocal methods while max- imizing the software flexibility to further development and modification will be discussed and addressed. A software named Relation-Based Sim- ulator (RBS) is developed for examining the proposed architecture. The exceptional capabilities of RBS will be explored by simulating three dis- tinguished models. RBS is available publicly and open to further develop- ment. The industrial acceptance of the RBS will be tested by targeting its performance on one Mac and two Linux distributions.}, subject = {Peridynamik}, language = {en} } @article{ArnoldKraus, author = {Arnold, Robert and Kraus, Matthias}, title = {On the nonstationary identification of climate-influenced loads for the semi-probabilistic approach using measured and projected data}, series = {Cogent Engineering}, volume = {2022}, journal = {Cogent Engineering}, number = {Volume 9, issue 1, article 2143061}, editor = {Pham, Duc}, publisher = {Taylor \& Francis}, address = {London}, doi = {10.1080/23311916.2022.2143061}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20221117-47363}, pages = {1 -- 26}, abstract = {A safe and economic structural design based on the semi-probabilistic concept requires statistically representative safety elements, such as characteristic values, design values, and partial safety factors. Regarding climate loads, the safety levels of current design codes strongly reflect experiences based on former measurements and investigations assuming stationary conditions, i.e. involving constant frequencies and intensities. However, due to climate change, occurrence of corresponding extreme weather events is expected to alter in the future influencing the reliability and safety of structures and their components. Based on established approaches, a systematically refined data-driven methodology for the determination of design parameters considering nonstationarity as well as standardized targets of structural reliability or safety, respectively, is therefore proposed. The presented procedure picks up fundamentals of European standardization and extends them with respect to nonstationarity by applying a shifting time window method. Taking projected snow loads into account, the application of the method is exemplarily demonstrated and various influencing parameters are discussed.}, subject = {Reliabilit{\"a}t}, language = {en} } @phdthesis{Jenabidehkordi, author = {Jenabidehkordi, Ali}, title = {An efficient adaptive PD formulation for complex microstructures}, doi = {10.25643/bauhaus-universitaet.4738}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20221116-47389}, school = {Bauhaus-Universit{\"a}t Weimar}, pages = {118}, abstract = {The computational costs of newly developed numerical simulation play a critical role in their acceptance within both academic use and industrial employment. Normally, the refinement of a method in the area of interest reduces the computational cost. This is unfortunately not true for most nonlocal simulation, since refinement typically increases the size of the material point neighborhood. Reducing the discretization size while keep- ing the neighborhood size will often require extra consideration. Peridynamic (PD) is a newly developed numerical method with nonlocal nature. Its straightforward integral form equation of motion allows simulating dynamic problems without any extra consideration required. The formation of crack and its propagation is known as natural to peridynamic. This means that discontinuity is a result of the simulation and does not demand any post-processing. As with other nonlocal methods, PD is considered an expensive method. The refinement of the nodal spacing while keeping the neighborhood size (i.e., horizon radius) constant, emerges to several nonphysical phenomena. This research aims to reduce the peridynamic computational and imple- mentation costs. A novel refinement approach is introduced. The pro- posed approach takes advantage of the PD flexibility in choosing the shape of the horizon by introducing multiple domains (with no intersections) to the nodes of the refinement zone. It will be shown that no ghost forces will be created when changing the horizon sizes in both subdomains. The approach is applied to both bond-based and state-based peridynamic and verified for a simple wave propagation refinement problem illustrating the efficiency of the method. Further development of the method for higher dimensions proves to have a direct relationship with the mesh sensitivity of the PD. A method for solving the mesh sensitivity of the PD is intro- duced. The application of the method will be examined by solving a crack propagation problem similar to those reported in the literature. New software architecture is proposed considering both academic and in- dustrial use. The available simulation tools for employing PD will be collected, and their advantages and drawbacks will be addressed. The challenges of implementing any node base nonlocal methods while max- imizing the software flexibility to further development and modification will be discussed and addressed. A software named Relation-Based Sim- ulator (RBS) is developed for examining the proposed architecture. The exceptional capabilities of RBS will be explored by simulating three distinguished models. RBS is available publicly and open to further develop- ment. The industrial acceptance of the RBS will be tested by targeting its performance on one Mac and two Linux distributions.}, subject = {Peridynamik}, language = {en} } @phdthesis{Zacharias, author = {Zacharias, Christin}, title = {Numerical Simulation Models for Thermoelastic Damping Effects}, doi = {10.25643/bauhaus-universitaet.4735}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20221116-47352}, school = {Bauhaus-Universit{\"a}t Weimar}, pages = {191}, abstract = {Finite Element Simulations of dynamically excited structures are mainly influenced by the mass, stiffness, and damping properties of the system, as well as external loads. The prediction quality of dynamic simulations of vibration-sensitive components depends significantly on the use of appropriate damping models. Damping phenomena have a decisive influence on the vibration amplitude and the frequencies of the vibrating structure. However, developing realistic damping models is challenging due to the multiple sources that cause energy dissipation, such as material damping, different types of friction, or various interactions with the environment. This thesis focuses on thermoelastic damping, which is the main cause of material damping in homogeneous materials. The effect is caused by temperature changes due to mechanical strains. In vibrating structures, temperature gradients arise in adjacent tension and compression areas. Depending on the vibration frequency, they result in heat flows, leading to increased entropy and the irreversible transformation of mechanical energy into thermal energy. The central objective of this thesis is the development of efficient simulation methods to incorporate thermoelastic damping in finite element analyses based on modal superposition. The thermoelastic loss factor is derived from the structure's mechanical mode shapes and eigenfrequencies. In subsequent analyses that are performed in the time and frequency domain, it is applied as modal damping. Two approaches are developed to determine the thermoelastic loss in thin-walled plate structures, as well as three-dimensional solid structures. The realistic representation of the dissipation effects is verified by comparing the simulation results with experimentally determined data. Therefore, an experimental setup is developed to measure material damping, excluding other sources of energy dissipation. The three-dimensional solid approach is based on the determination of the generated entropy and therefore the generated heat per vibration cycle, which is a measure for thermoelastic loss in relation to the total strain energy. For thin plate structures, the amount of bending energy in a modal deformation is calculated and summarized in the so-called Modal Bending Factor (MBF). The highest amount of thermoelastic loss occurs in the state of pure bending. Therefore, the MBF enables a quantitative classification of the mode shapes concerning the thermoelastic damping potential. The results of the developed simulations are in good agreement with the experimental results and are appropriate to predict thermoelastic loss factors. Both approaches are based on modal superposition with the advantage of a high computational efficiency. Overall, the modeling of thermoelastic damping represents an important component in a comprehensive damping model, which is necessary to perform realistic simulations of vibration processes.}, subject = {Werkstoffd{\"a}mpfung}, language = {en} } @article{Lutolli, author = {Lutolli, Blerim}, title = {A Review of Domed Cities and Architecture: Past, Present and Future}, series = {Future cities and environment}, volume = {2022}, journal = {Future cities and environment}, number = {Volume 8, issue 1}, publisher = {Ubiquity Press Limited}, address = {London}, doi = {10.5334/fce.154}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20221103-47335}, pages = {1 -- 9}, abstract = {The goal of architecture is changing in response to the expanding role of cities, rapid urbanization, and transformation under changing economic, environmental, social, and demographic factors. As cities increased in the early modern era, overcrowding, urbanization, and pollution conditions led reformers to consider the future shape of the cities. One of the most critical topics in contemporary architecture is the subject of the future concepts of living. In most cases, domed cities, as a future concept of living, are rarely considered, and they are used chiefly as "utopian" visions in the discourse of future ways of living. This paper highlights the reviews of domed cities to deepen the understanding of the idea in practice, like its approach in terms of architecture. The main aim of this paper is to provide a broad overview for domed cities in the face of pollution as one of the main concerns in many European cities. As a result, the significance of the reviews of the existing projects is focused on their conceptual quality. This review will pave the way for further studies in terms of future developments in the realm of domed cities. In this paper, the city of Celje, one of the most polluted cities in Slovenia, is taken as a case study for considering the concept of Dome incorporated due to the lack of accessible literature on the topic. This review's primary contribution is to allow architects to explore a broad spectrum of innovation by comparing today's achievable statuses against the possibilities generated by domed cities. As a result of this study, the concept of living under the Dome remains to be developed in theory and practice. The current challenging climatic situation will accelerate the evolution of these concepts, resulting in the formation of new typologies, which are a requirement for humanity.}, subject = {Architektur}, language = {en} } @article{ChowdhuryKraus, author = {Chowdhury, Sharmistha and Kraus, Matthias}, title = {Design-related reassessment of structures integrating Bayesian updating of model safety factors}, series = {Results in Engineering}, volume = {2022}, journal = {Results in Engineering}, number = {Volume 16, article 100560}, publisher = {Elsevier}, address = {Amsterdam}, doi = {10.1016/j.rineng.2022.100560}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20221028-47294}, pages = {1 -- 1}, abstract = {In the semi-probabilistic approach of structural design, the partial safety factors are defined by considering some degree of uncertainties to actions and resistance, associated with the parameters' stochastic nature. However, uncertainties for individual structures can be better examined by incorporating measurement data provided by sensors from an installed health monitoring scheme. In this context, the current study proposes an approach to revise the partial safety factor for existing structures on the action side, γE by integrating Bayesian model updating. A simple numerical example of a beam-like structure with artificially generated measurement data is used such that the influence of different sensor setups and data uncertainties on revising the safety factors can be investigated. It is revealed that the health monitoring system can reassess the current capacity reserve of the structure by updating the design safety factors, resulting in a better life cycle assessment of structures. The outcome is furthermore verified by analysing a real life small railway steel bridge ensuring the applicability of the proposed method to practical applications.}, subject = {Lebenszyklus}, language = {en} } @article{ChowdhuryZabel, author = {Chowdhury, Sharmistha and Zabel, Volkmar}, title = {Influence of loading sequence on wind induced fatigue assessment of bolts in TV-tower connection block}, series = {Results in Engineering}, volume = {2022}, journal = {Results in Engineering}, number = {Volume 16, article 100603}, publisher = {Elsevier}, address = {Amsterdam}, doi = {10.1016/j.rineng.2022.100603}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20221028-47303}, pages = {1 -- 18}, abstract = {Bolted connections are widely employed in structures like transmission poles, wind turbines, and television (TV) towers. The behaviour of bolted connections is often complex and plays a significant role in the overall dynamic characteristics of the structure. The goal of this work is to conduct a fatigue lifecycle assessment of such a bolted connection block of a 193 m tall TV tower, for which 205 days of real measurement data have been obtained from the installed monitoring devices. Based on the recorded data, the best-fit stochastic wind distribution for 50 years, the decisive wind action, and the locations to carry out the fatigue analysis have been decided. A 3D beam model of the entire tower is developed to extract the nodal forces corresponding to the connection block location under various mean wind speeds, which is later coupled with a detailed complex finite element model of the connection block, with over three million degrees of freedom, for acquiring stress histories on some pre-selected bolts. The random stress histories are analysed using the rainflow counting algorithm (RCA) and the damage is estimated using Palmgren-Miner's damage accumulation law. A modification is proposed to integrate the loading sequence effect into the RCA, which otherwise is ignored, and the differences between the two RCAs are investigated in terms of the accumulated damage.}, subject = {Schadensakkumulation}, language = {en} } @article{HarirchianIsik, author = {Harirchian, Ehsan and Isik, Ercan}, title = {A Comparative Probabilistic Seismic Hazard Analysis for Eastern Turkey (Bitlis) Based on Updated Hazard Map and Its Effect on Regular RC Structures}, series = {Buildings}, volume = {2022}, journal = {Buildings}, number = {Volume 12, issue 10, article 1573}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/buildings12101573}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20221028-47283}, pages = {1 -- 19}, abstract = {Determining the earthquake hazard of any settlement is one of the primary studies for reducing earthquake damage. Therefore, earthquake hazard maps used for this purpose must be renewed over time. Turkey Earthquake Hazard Map has been used instead of Turkey Earthquake Zones Map since 2019. A probabilistic seismic hazard was performed by using these last two maps and different attenuation relationships for Bitlis Province (Eastern Turkey) were located in the Lake Van Basin, which has a high seismic risk. The earthquake parameters were determined by considering all districts and neighborhoods in the province. Probabilistic seismic hazard analyses were carried out for these settlements using seismic sources and four different attenuation relationships. The obtained values are compared with the design spectrum stated in the last two earthquake maps. Significant differences exist between the design spectrum obtained according to the different exceedance probabilities. In this study, adaptive pushover analyses of sample-reinforced concrete buildings were performed using the design ground motion level. Structural analyses were carried out using three different design spectra, as given in the last two seismic design codes and the mean spectrum obtained from attenuation relationships. Different design spectra significantly change the target displacements predicted for the performance levels of the buildings.}, subject = {Erbeben}, language = {en} } @phdthesis{Zhang, author = {Zhang, Yongzheng}, title = {A Nonlocal Operator Method for Quasi-static and Dynamic Fracture Modeling}, doi = {10.25643/bauhaus-universitaet.4732}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20221026-47321}, school = {Bauhaus-Universit{\"a}t Weimar}, abstract = {Material failure can be tackled by so-called nonlocal models, which introduce an intrinsic length scale into the formulation and, in the case of material failure, restore the well-posedness of the underlying boundary value problem or initial boundary value problem. Among nonlocal models, peridynamics (PD) has attracted a lot of attention as it allows the natural transition from continuum to discontinue and thus allows modeling of discrete cracks without the need to describe and track the crack topology, which has been a major obstacle in traditional discrete crack approaches. This is achieved by replacing the divergence of the Cauchy stress tensor through an integral over so-called bond forces, which account for the interaction of particles. A quasi-continuum approach is then used to calibrate the material parameters of the bond forces, i.e., equating the PD energy with the energy of a continuum. One major issue for the application of PD to general complex problems is that they are limited to fairly simple material behavior and pure mechanical problems based on explicit time integration. PD has been extended to other applications but losing simultaneously its simplicity and ease in modeling material failure. Furthermore, conventional PD suffers from instability and hourglass modes that require stabilization. It also requires the use of constant horizon sizes, which drastically reduces its computational efficiency. The latter issue was resolved by the so-called dual-horizon peridynamics (DH-PD) formulation and the introduction of the duality of horizons. Within the nonlocal operator method (NOM), the concept of nonlocality is further extended and can be considered a generalization of DH-PD. Combined with the energy functionals of various physical models, the nonlocal forms based on the dual-support concept can be derived. In addition, the variation of the energy functional allows implicit formulations of the nonlocal theory. While traditional integral equations are formulated in an integral domain, the dual-support approaches are based on dual integral domains. One prominent feature of NOM is its compatibility with variational and weighted residual methods. The NOM yields a direct numerical implementation based on the weighted residual method for many physical problems without the need for shape functions. Only the definition of the energy or boundary value problem is needed to drastically facilitate the implementation. The nonlocal operator plays an equivalent role to the derivatives of the shape functions in meshless methods and finite element methods (FEM). Based on the variational principle, the residual and the tangent stiffness matrix can be obtained with ease by a series of matrix multiplications. In addition, NOM can be used to derive many nonlocal models in strong form. The principal contributions of this dissertation are the implementation and application of NOM, and also the development of approaches for dealing with fractures within the NOM, mostly for dynamic fractures. The primary coverage and results of the dissertation are as follows: -The first/higher-order implicit NOM and explicit NOM, including a detailed description of the implementation, are presented. The NOM is based on so-called support, dual-support, nonlocal operators, and an operate energy functional ensuring stability. The nonlocal operator is a generalization of the conventional differential operators. Combining with the method of weighted residuals and variational principles, NOM establishes the residual and tangent stiffness matrix of operate energy functional through some simple matrix without the need of shape functions as in other classical computational methods such as FEM. NOM only requires the definition of the energy drastically simplifying its implementation. For the sake of conciseness, the implementation in this chapter is focused on linear elastic solids only, though the NOM can handle more complex nonlinear problems. An explicit nonlocal operator method for the dynamic analysis of elasticity solid problems is also presented. The explicit NOM avoids the calculation of the tangent stiffness matrix as in the implicit NOM model. The explicit scheme comprises the Verlet-velocity algorithm. The NOM can be very flexible and efficient for solving partial differential equations (PDEs). It's also quite easy for readers to use the NOM and extend it to solve other complicated physical phenomena described by one or a set of PDEs. Several numerical examples are presented to show the capabilities of this method. -A nonlocal operator method for the dynamic analysis of (thin) Kirchhoff plates is proposed. The nonlocal Hessian operator is derived from a second-order Taylor series expansion. NOM is higher-order continuous, which is exploited for thin plate analysis that requires \$C^1\$ continuity. The nonlocal dynamic governing formulation and operator energy functional for Kirchhoff plates are derived from a variational principle. The Verlet-velocity algorithm is used for time discretization. After confirming the accuracy of the nonlocal Hessian operator, several numerical examples are simulated by the nonlocal dynamic Kirchhoff plate formulation. -A nonlocal fracture modeling is developed and applied to the simulation of quasi-static and dynamic fractures using the NOM. The phase field's nonlocal weak and associated strong forms are derived from a variational principle. The NOM requires only the definition of energy. We present both a nonlocal implicit phase field model and a nonlocal explicit phase field model for fracture; the first approach is better suited for quasi-static fracture problems, while the key application of the latter one is dynamic fracture. To demonstrate the performance of the underlying approach, several benchmark examples for quasi-static and dynamic fracture are solved.}, subject = {Variationsprinzip}, language = {en} } @misc{ZandersBein, author = {Zanders, Theresa and Bein, Laura Eleana}, title = {Der anonyme Behandlungsschein - von der Idee zur Umsetzung. Ein Handlungsleitfaden}, editor = {Calbet i Elias, Laura and Vollmer, Lisa and Zanders, Theresa}, doi = {10.25643/bauhaus-universitaet.4716}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20220928-47161}, abstract = {Der vorliegende Handlungsleitfaden hilft zivilgesellschaftlichen Organisationen und staatlichen Einrichtungen bei der Installation eines anonymen Behandlungs- oder Krankenschein f{\"u}r Menschen ohne Krankenversicherung. Dabei b{\"u}ndelt sich hier der Erfahrungsschatz verschiedener Initiativen aus dem gesamten Bundesgebiet.}, subject = {Gesundheitsversorgung}, language = {de} } @article{MaiwaldSchwarzKaufmannetal., author = {Maiwald, Holger and Schwarz, Jochen and Kaufmann, Christian and Langhammer, Tobias and Golz, Sebastian and Wehner, Theresa}, title = {Innovative Vulnerability and Risk Assessment of Urban Areas against Flood Events: Prognosis of Structural Damage with a New Approach Considering Flow Velocity}, series = {Water}, volume = {2022}, journal = {Water}, number = {Volume 14, issue 18, article 2793}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/w14182793}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20221012-47254}, pages = {1 -- 28}, abstract = {The floods in 2002 and 2013, as well as the recent flood of 2021, caused billions Euros worth of property damage in Germany. The aim of the project Innovative Vulnerability and Risk Assessment of Urban Areas against Flood Events (INNOVARU) involved the development of a practicable flood damage model that enables realistic damage statements for the residential building stock. In addition to the determination of local flood risks, it also takes into account the vulnerability of individual buildings and allows for the prognosis of structural damage. In this paper, we discuss an improved method for the prognosis of structural damage due to flood impact. Detailed correlations between inundation level and flow velocities depending on the vulnerability of the building types, as well as the number of storeys, are considered. Because reliable damage data from events with high flow velocities were not available, an innovative approach was adopted to cover a wide range of flow velocities. The proposed approach combines comprehensive damage data collected after the 2002 flood in Germany with damage data of the 2011 Tohoku earthquake tsunami in Japan. The application of the developed methods enables a reliable reinterpretation of the structural damage caused by the August flood of 2002 in six study areas in the Free State of Saxony.}, subject = {Bauschaden}, language = {en} } @phdthesis{OrtizAlvis, author = {Ortiz Alvis, Alfredo}, title = {Urban Agoraphobia: The pursuit of security within confined community ties. Urban-ethnographic analysis on gated housing developments of Guadalajara, Mexico.}, doi = {10.25643/bauhaus-universitaet.4723}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20221005-47234}, school = {Bauhaus-Universit{\"a}t Weimar}, pages = {436}, abstract = {The Gated Community (GC) phenomenon in Latin American cities has become an inherent element of their urban development, despite academical debate, their approach thrives within the housing market; not surprisingly, as some of the premises on which GCs are based, namely safety, control and supervision intersperse seamlessly with the insecure conditions of the contexts from which they arise. The current security crisis in Mexico, triggered in 2006 by the so-called war on drugs, has reached its peak with the highest insecurity rates in decades, representing a unique chance to study these interactions. Although the leading term of this research, Urban Agoraphobia, implies a causal dichotomy between the rise in the sense of fear amongst citizens and housing confinement as lineal consequence, I acknowledge that GCs represent a complex phenomenon, a hub of diverse factors and multidimensional processes held on four fundamental levels: global, social, individual and state-related. The focus of this dissertation is set on the individual plane and contributes, from the analysis of the GC's resident's perspective, experiences and perceptions, to a debate that has usually been limited to the scrutiny of other drivers, disregarding the role of dweller's underlying fears, motivations and concerns. Assuming that the current ruling security model in Mexico tends to empower its commodification rather than its collective quality, this research draws upon the use of a methodological triangulation, along conceptual and contextual analyses, to test the hypothesis that insecurity plays an increasingly major role, leading citizens into the belief that acquiring a household in a controlled and surveilled community represents a counterweight against the feared environment of the open city. The focus of the analysis lies on the internal hatch of community ties as potential palliative for the provision of a sense of security, aiming to transcend the unidimensional discourse of GCs as defined mainly by their defensive apparatus. Residents' perspectives acquired through ethnographical analyses may provide the chance to gain an essential view into a phenomenon that further consolidates without a critical study of its actual implications, not only for Mexican cities, but also for the Latin American and global contexts.}, subject = {Agoraphobie}, language = {en} } @misc{CarvalhoDaher, type = {Master Thesis}, author = {Carvalho Daher, Cesar Felipe}, title = {Horoskopos: a virtual planetarium for astrology}, doi = {10.25643/bauhaus-universitaet.4718}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20220930-47181}, school = {Bauhaus-Universit{\"a}t Weimar}, pages = {104}, abstract = {This report details the development of Horoskopos, a virtual planetarium for astrology. This project was an attempt to develop a learning tool for studying astrological concepts as connected to observational astronomy. The premise that astrology and observational astronomy were once inseparable from each other in ancient times guided the conceptualization of this tool as an interactive planetarium. The main references were existing software and applications for visualization in astrology and astronomy. Professional astrology teachers were consulted in order to understand better the state of astrological teaching and learning, as well as existing tools and practice. Horoskopos was built using the Unity3D development interface, which is based on the C\# programming language. It also relied on the Swiss Ephemeris coding interface from Astrodienst. The development process was experimental and many of the needed skills were developed as needed. Usability tests were performed as new features were added to the interface. The final version of Horoskopos is fully usable, with many interactive visualization features and a defined visual identity. It was validated together with professional astrologers for its effectiveness in concept and visualization.}, subject = {Mediendesign}, language = {en} } @phdthesis{Yousefi, author = {Yousefi, Hassan}, title = {Discontinuous propagating fronts: linear and nonlinear systems}, doi = {10.25643/bauhaus-universitaet.4717}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20220922-47178}, school = {Bauhaus-Universit{\"a}t Weimar}, pages = {356}, abstract = {The aim of this study is controlling of spurious oscillations developing around discontinuous solutions of both linear and non-linear wave equations or hyperbolic partial differential equations (PDEs). The equations include both first-order and second-order (wave) hyperbolic systems. In these systems even smooth initial conditions, or smoothly varying source (load) terms could lead to discontinuous propagating solutions (fronts). For the first order hyperbolic PDEs, the concept of central high resolution schemes is integrated with the multiresolution-based adaptation to capture properly both discontinuous propagating fronts and effects of fine-scale responses on those of larger scales in the multiscale manner. This integration leads to using central high resolution schemes on non-uniform grids; however, such simulation is unstable, as the central schemes are originally developed to work properly on uniform cells/grids. Hence, the main concern is stable collaboration of central schemes and multiresoltion-based cell adapters. Regarding central schemes, the considered approaches are: 1) Second order central and central-upwind schemes; 2) Third order central schemes; 3) Third and fourth order central weighted non-oscillatory schemes (central-WENO or CWENO); 4) Piece-wise parabolic methods (PPMs) obtained with two different local stencils. For these methods, corresponding (nonlinear) stability conditions are studied and modified, as well. Based on these stability conditions several limiters are modified/developed as follows: 1) Several second-order limiters with total variation diminishing (TVD) feature, 2) Second-order uniformly high order accurate non-oscillatory (UNO) limiters, 3) Two third-order nonlinear scaling limiters, 4) Two new limiters for PPMs. Numerical results show that adaptive solvers lead to cost-effective computations (e.g., in some 1-D problems, number of adapted grid points are less than 200 points during simulations, while in the uniform-grid case, to have the same accuracy, using of 2049 points is essential). Also, in some cases, it is confirmed that fine scale responses have considerable effects on higher scales. In numerical simulation of nonlinear first order hyperbolic systems, the two main concerns are: convergence and uniqueness. The former is important due to developing of the spurious oscillations, the numerical dispersion and the numerical dissipation. Convergence in a numerical solution does not guarantee that it is the physical/real one (the uniqueness feature). Indeed, a nonlinear systems can converge to several numerical results (which mathematically all of them are true). In this work, the convergence and uniqueness are directly studied on non-uniform grids/cells by the concepts of local numerical truncation error and numerical entropy production, respectively. Also, both of these concepts have been used for cell/grid adaptations. So, the performance of these concepts is also compared by the multiresolution-based method. Several 1-D and 2-D numerical examples are examined to confirm the efficiency of the adaptive solver. Examples involve problems with convex and non-convex fluxes. In the latter case, due to developing of complex waves, proper capturing of real answers needs more attention. For this purpose, using of method-adaptation seems to be essential (in parallel to the cell/grid adaptation). This new type of adaptation is also performed in the framework of the multiresolution analysis. Regarding second order hyperbolic PDEs (mechanical waves), the regularization concept is used to cure artificial (numerical) oscillation effects, especially for high-gradient or discontinuous solutions. There, oscillations are removed by the regularization concept acting as a post-processor. Simulations will be performed directly on the second-order form of wave equations. It should be mentioned that it is possible to rewrite second order wave equations as a system of first-order waves, and then simulated the new system by high resolution schemes. However, this approach ends to increasing of variable numbers (especially for 3D problems). The numerical discretization is performed by the compact finite difference (FD) formulation with desire feature; e.g., methods with spectral-like or optimized-error properties. These FD methods are developed to handle high frequency waves (such as waves near earthquake sources). The performance of several regularization approaches is studied (both theoretically and numerically); at last, a proper regularization approach controlling the Gibbs phenomenon is recommended. At the end, some numerical results are provided to confirm efficiency of numerical solvers enhanced by the regularization concept. In this part, shock-like responses due to local and abrupt changing of physical properties, and also stress wave propagation in stochastic-like domains are studied.}, subject = {Partielle Differentialgleichung}, language = {en} } @article{MehlingSchnabelLondong, author = {Mehling, Simon and Schnabel, Tobias and Londong, J{\"o}rg}, title = {Investigation on Energetic Efficiency of Reactor Systems for Oxidation of Micro-Pollutants by Immobilized Active Titanium Dioxide Photocatalysis}, series = {Water}, volume = {2022}, journal = {Water}, number = {Volume 14, issue 7, article 2681}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/w14172681}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20220912-47130}, pages = {1 -- 15}, abstract = {In this work, the degradation performance for the photocatalytic oxidation of eight micropollutants (amisulpride, benzotriazole, candesartan, carbamazepine, diclofenac, gabapentin, methlybenzotriazole, and metoprolol) within real secondary effluent was investigated using three different reactor designs. For all reactor types, the influence of irradiation power on its reaction rate and energetic efficiency was investigated. Flat cell and batch reactor showed almost similar substance specific degradation behavior. Within the immersion rotary body reactor, benzotriazole and methylbenzotriazole showed a significantly lower degradation affinity. The flat cell reactor achieved the highest mean degradation rate, with half time values ranging from 5 to 64 min with a mean of 18 min, due to its high catalysts surface to hydraulic volume ratio. The EE/O values were calculated for all micro-pollutants as well as the mean degradation rate constant of each experimental step. The lowest substance specific energy per order (EE/O) values of 5 kWh/m3 were measured for benzotriazole within the batch reactor. The batch reactor also reached the lowest mean values (11.8-15.9 kWh/m3) followed by the flat cell reactor (21.0-37.0 kWh/m3) and immersion rotary body reactor (23.9-41.0 kWh/m3). Catalyst arrangement and irradiation power were identified as major influences on the energetic performance of the reactors. Low radiation intensities as well as the use of submerged catalyst arrangement allowed a reduction in energy demand by a factor of 3-4. A treatment according to existing treatment goals of wastewater treatment plants (80\% total degradation) was achieved using the batch reactor with a calculated energy demand of 7000 Wh/m3.}, subject = {Fotokatalyse}, language = {en} } @phdthesis{CarvajalBermudez, author = {Carvajal Berm{\´u}dez, Juan Carlos}, title = {New methods of citizen participation based on digital technologies}, doi = {10.25643/bauhaus-universitaet.4712}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20220906-47124}, school = {Bauhaus-Universit{\"a}t Weimar}, abstract = {The current thesis presents research about new methods of citizen participation based on digital technologies. The focus on the research lies on decentralized methods of participation where citizens take the role of co-creators. The research project first conducted a review of the literature on citizen participation, its origins and the different paradigms that have emerged over the years. The literature review also looked at the influence of technologies on participation processes and the theoretical frameworks that have emerged to understand the introduction of technologies in the context of urban development. The literature review generated the conceptual basis for the further development of the thesis. The research begins with a survey of technology enabled participation applications that examined the roles and structures emerging due to the introduction of technology. The results showed that cities use technology mostly to control and monitor urban infrastructure and are rather reluctant to give citizens the role of co-creators. Based on these findings, three case studies were developed. Digital tools for citizen participation were conceived and introduced for each case study. The adoption and reaction of the citizens were observed using three data collection methods. The results of the case studies showed consistently that previous participation and engagement with informal citizen participation are a determinining factor in the potential adoption of digital tools for decentralized engagement. Based on these results, the case studies proposed methods and frameworks that can be used for the conception and introduction of technologies for decentralized citizen participation.}, subject = {Partizipation}, language = {en} } @phdthesis{LopezZermeno, author = {L{\´o}pez Zerme{\~n}o, Jorge Alberto}, title = {Isogeometric and CAD-based methods for shape and topology optimization: Sensitivity analysis, B{\´e}zier elements and phase-field approaches}, doi = {10.25643/bauhaus-universitaet.4710}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20220831-47102}, school = {Bauhaus-Universit{\"a}t Weimar}, abstract = {The Finite Element Method (FEM) is widely used in engineering for solving Partial Differential Equations (PDEs) over complex geometries. To this end, it is required to provide the FEM software with a geometric model that is typically constructed in a Computer-Aided Design (CAD) software. However, FEM and CAD use different approaches for the mathematical description of the geometry. Thus, it is required to generate a mesh, which is suitable for FEM, based on the CAD model. Nonetheless, this procedure is not a trivial task and it can be time consuming. This issue becomes more significant for solving shape and topology optimization problems, which consist in evolving the geometry iteratively. Therefore, the computational cost associated to the mesh generation process is increased exponentially for this type of applications. The main goal of this work is to investigate the integration of CAD and CAE in shape and topology optimization. To this end, numerical tools that close the gap between design and analysis are presented. The specific objectives of this work are listed below: • Automatize the sensitivity analysis in an isogeometric framework for applications in shape optimization. Applications for linear elasticity are considered. • A methodology is developed for providing a direct link between the CAD model and the analysis mesh. In consequence, the sensitivity analysis can be performed in terms of the design variables located in the design model. • The last objective is to develop an isogeometric method for shape and topological optimization. This method should take advantage of using Non-Uniform Rational B-Splines (NURBS) with higher continuity as basis functions. Isogeometric Analysis (IGA) is a framework designed to integrate the design and analysis in engineering problems. The fundamental idea of IGA is to use the same basis functions for modeling the geometry, usually NURBS, for the approximation of the solution fields. The advantage of integrating design and analysis is two-fold. First, the analysis stage is more accurate since the system of PDEs is not solved using an approximated geometry, but the exact CAD model. Moreover, providing a direct link between the design and analysis discretizations makes possible the implementation of efficient sensitivity analysis methods. Second, the computational time is significantly reduced because the mesh generation process can be avoided. Sensitivity analysis is essential for solving optimization problems when gradient-based optimization algorithms are employed. Automatic differentiation can compute exact gradients, automatically by tracking the algebraic operations performed on the design variables. For the automation of the sensitivity analysis, an isogeometric framework is used. Here, the analysis mesh is obtained after carrying out successive refinements, while retaining the coarse geometry for the domain design. An automatic differentiation (AD) toolbox is used to perform the sensitivity analysis. The AD toolbox takes the code for computing the objective and constraint functions as input. Then, using a source code transformation approach, it outputs a code for computing the objective and constraint functions, and their sensitivities as well. The sensitivities obtained from the sensitivity propagation method are compared with analytical sensitivities, which are computed using a full isogeometric approach. The computational efficiency of AD is comparable to that of analytical sensitivities. However, the memory requirements are larger for AD. Therefore, AD is preferable if the memory requirements are satisfied. Automatic sensitivity analysis demonstrates its practicality since it simplifies the work of engineers and designers. Complex geometries with sharp edges and/or holes cannot easily be described with NURBS. One solution is the use of unstructured meshes. Simplex-elements (triangles and tetrahedra for two and three dimensions respectively) are particularly useful since they can automatically parameterize a wide variety of domains. In this regard, unstructured B{\´e}zier elements, commonly used in CAD, can be employed for the exact modelling of CAD boundary representations. In two dimensions, the domain enclosed by NURBS curves is parameterized with B{\´e}zier triangles. To describe exactly the boundary of a two-dimensional CAD model, the continuity of a NURBS boundary representation is reduced to C^0. Then, the control points are used to generate a triangulation such that the boundary of the domain is identical to the initial CAD boundary representation. Thus, a direct link between the design and analysis discretizations is provided and the sensitivities can be propagated to the design domain. In three dimensions, the initial CAD boundary representation is given as a collection of NURBS surfaces that enclose a volume. Using a mesh generator (Gmsh), a tetrahedral mesh is obtained. The original surface is reconstructed by modifying the location of the control points of the tetrahedral mesh using B{\´e}zier tetrahedral elements and a point inversion algorithm. This method offers the possibility of computing the sensitivity analysis using the analysis mesh. Then, the sensitivities can be propagated into the design discretization. To reuse the mesh originally generated, a moving B{\´e}zier tetrahedral mesh approach was implemented. A gradient-based optimization algorithm is employed together with a sensitivity propagation procedure for the shape optimization cases. The proposed shape optimization approaches are used to solve some standard benchmark problems in structural mechanics. The results obtained show that the proposed approach can compute accurate gradients and evolve the geometry towards optimal solutions. In three dimensions, the moving mesh approach results in faster convergence in terms of computational time and avoids remeshing at each optimization step. For considering topological changes in a CAD-based framework, an isogeometric phase-field based shape and topology optimization is developed. In this case, the diffuse interface of a phase-field variable over a design domain implicitly describes the boundaries of the geometry. The design variables are the local values of the phase-field variable. The descent direction to minimize the objective function is found by using the sensitivities of the objective function with respect to the design variables. The evolution of the phase-field is determined by solving the time dependent Allen-Cahn equation. Especially for topology optimization problems that require C^1 continuity, such as for flexoelectric structures, the isogeometric phase field method is of great advantage. NURBS can achieve the desired continuity more efficiently than the traditional employed functions. The robustness of the method is demonstrated when applied to different geometries, boundary conditions, and material configurations. The applications illustrate that compared to piezoelectricity, the electrical performance of flexoelectric microbeams is larger under bending. In contrast, the electrical power for a structure under compression becomes larger with piezoelectricity.}, subject = {CAD}, language = {en} } @article{AlYasiriMutasharGuerlebecketal., author = {Al-Yasiri, Zainab Riyadh Shaker and Mutashar, Hayder Majid and G{\"u}rlebeck, Klaus and Lahmer, Tom}, title = {Damage Sensitive Signals for the Assessment of the Conditions of Wind Turbine Rotor Blades Using Electromagnetic Waves}, series = {Infrastructures}, volume = {2022}, journal = {Infrastructures}, number = {Volume 7, Issue 8 (August 2022), article 104}, editor = {Shafiullah, GM}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/infrastructures7080104}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20220831-47093}, pages = {18}, abstract = {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.}, subject = {Windkraftwerk}, language = {en} } @article{ArtusKoch, author = {Artus, Mathias and Koch, Christian}, title = {Object-Oriented Damage Information Modeling Concepts and Implementation for Bridge Inspection}, series = {Journal of Computing in Civil Engineering}, volume = {2022}, journal = {Journal of Computing in Civil Engineering}, number = {Volume 36, issue 6}, doi = {10.1061/(ASCE)CP.1943-5487.0001030}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20220826-47087}, pages = {1 -- 21}, abstract = {Bridges are designed to last for more than 50 years and consume up to 50\% of their life-cycle costs during their operation phase. Several inspections and assessment actions are executed during this period. Bridge and damage information must be gathered, digitized, and exchanged between different stakeholders. Currently, the inspection and assessment practices rely on paper-based data collection and exchange, which is time-consuming and error-prone, and leads to loss of information. Storing and exchanging damage and building information in a digital format may lower costs and errors during inspection and assessment and support future needs, for example, immediate simulations regarding performance assessment, automated maintenance planning, and mixed reality inspections. This study focused on the concept for modeling damage information to support bridge reviews and structural analysis. Starting from the definition of multiple use cases and related requirements, the data model for damage information is defined independently from the subsequent implementation. In the next step, the implementation via an established standard is explained. Functional tests aim to identify problems in the concept and implementation. To show the capability of the final model, two example use cases are illustrated: the inspection review of the entire bridge and a finite-element analysis of a single component. Main results are the definition of necessary damage data, an object-oriented damage model, which supports multiple use cases, and the implementation of the model in a standard. Furthermore, the tests have shown that the standard is suitable to deliver damage information; however, several software programs lack proper implementation of the standard.}, subject = {Building Information Modeling}, language = {en} } @phdthesis{Riechert, author = {Riechert, Christin}, title = {Hydratation und Eigenschaften von Gips-Zement-Puzzolan-Bindemitteln mit alumosilikatischen Puzzolanen}, isbn = {978-3-00-073003-0}, doi = {10.25643/bauhaus-universitaet.4707}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20220825-47076}, school = {Bauhaus-Universit{\"a}t Weimar}, pages = {148}, abstract = {Reine Calciumsulfatbindemittel weisen eine hohe L{\"o}slichkeit auf. Feuchteinwirkung f{\"u}hrt zudem zu starken Festigkeitsverlusten. Aus diesem Grund werden diese Bindemittel ausschließlich f{\"u}r Baustoffe und -produkte im Innenbereich ohne permanenten Feuchtebeanspruchung eingesetzt. Eine M{\"o}glichkeit, die Feuchtebest{\"a}ndigkeit zu erh{\"o}hen, ist die Beimischung puzzolanischer und zement{\"a}rer Komponenten. Diese Mischsysteme werden Gips-Zement-Puzzolan-Bindemittel (kurz: GZPB) genannt. Mischungen aus Calciumsulfaten und Portlandzementen allein sind aufgrund der treibenden Ettringitbildung nicht raumbest{\"a}ndig. Durch die Zugabe von puzzolanischen Stoffen k{\"o}nnen aber Bedingungen im hydratisierenden System geschaffen werden, welche eine rissfreie Erh{\"a}rtung erm{\"o}glichen. Hierf{\"u}r ist eine exakte Rezeptierung der GZPB notwendig, um die GZPB-typischen, ettringitbedingten Dehnungen zeitlich zu begrenzen. Insbesondere bei alumosilikatischen Puzzolanen treten w{\"a}hrend der Hydratation gegen{\"u}ber rein silikatischen Puzzolanen deutlich h{\"o}here Expansionen auf, wodurch die Gefahr einer potenziellen Rissbildung steigt. F{\"u}r die Erstellung geeigneter GZPB-Zusammensetzungen bedarf es daher einer Methodik, um raumbest{\"a}ndig erh{\"a}rtende Systeme sicher von destruktiven Mischungen unterscheiden zu k{\"o}nnen. Sowohl f{\"u}r die Rezeptierung als auch f{\"u}r die Anwendung der GZPB existieren in Deutschland keinerlei Normen. Dar{\"u}ber hinaus sind die Hydratationsvorg{\"a}nge sowie die entstehenden Produkte nicht konsistent beschrieben. Auch auf die Besonderheiten der GZPB mit alumosilikatischen Puzzolanen wird in der Literatur nur unzureichend eingegangen. Ziel war es daher, ein grundlegendes Verst{\"a}ndnis der Hydratation sowie eine sichere Methodik zur Rezeptierung raumbest{\"a}ndig und rissfrei erh{\"a}rtender GZPB, insbesondere in Hinblick auf die Verwendung alumosilikatischer Puzzolane, zu erarbeiten. Dar{\"u}ber hinaus sollte systematisch der Einfluss der Einzelkomponenten auf Hydratation und Eigenschaften dieser Bindemittelsysteme untersucht werden. Dies soll erm{\"o}glichen, die GZPB f{\"u}r ein breites Anwendungsspektrum als Bindemittel zu etablieren, und somit vorteilhafte Eigenschaften der Calciumsulfate (geringe Schwindneigung, geringe CO2-Emission etc.) mit der Leistungs-f{\"a}higkeit von Zementen (Wasserbest{\"a}ndigkeit, Festigkeit, Dauerhaftigkeit etc.) zu verbinden. Als Ausgangsstoffe der Untersuchungen zu den GZPB wurden Stuckgips und Alpha-Halbhydrat als Calciumsulfatbindemittel in unterschiedlichen Anteilen im GZPB verwendet. Die Puzzolan-Zement-Verh{\"a}ltnisse wurden ebenfalls variiert. Als Puzzolan kam f{\"u}r den Großteil der Untersuchungen ein alumosilikatisches Metakaolin zum Einsatz. Als kalkspendende Komponente diente ein reiner Portlandzement. Das Untersuchungsprogramm gliederte sich in 4 Teile. Zuerst wurde anhand von CaO- und pH-Wert-Messungen in Suspensionen sowie dem L{\"a}ngen{\"a}nderungsverhalten von Bindemittelleimen verschiedener Zusammensetzungen eine Vorauswahl geeigneter GZPB-Rezepturen ermittelt. Danach erfolgten, ebenfalls an Bindemittelleimen, Untersuchungen zu den Eigenschaften der als geeignet eingesch{\"a}tzten GZPB-Mischungen. Hierzu z{\"a}hlten Langzeitbetrachtungen zur rissfreien Erh{\"a}rtung bei unterschiedlichen Umgebungsbedingungen sowie die Festigkeitsentwicklung im trockenen und feuchten Zustand. Im n{\"a}chsten Schritt wurde anhand zweier exemplarischer GZPB-Zusammensetzungen (mit silikatischen und alumosilikatischen Puzzolan) die prinzipiell m{\"o}gliche Phasenzusammensetzung unter Variation des Puzzolan-Zement-Verh{\"a}ltnisses (P/Z-Verh{\"a}ltnis) und des Calciumsulfatanteils im thermodynamischen Gleichgewichtszustand berechnet. Hier wurde im Besonderen auf Unterschiede der silikatischen und alumosilikatischen Puzzolane eingegangen. Im letzten Teil der Untersuchungen wurden die Hydratationskinetik der GZPB sowie die Gef{\"u}geentwicklung n{\"a}her betrachtet. Hierf{\"u}r wurden die Porenl{\"o}sungen chemisch analysiert und S{\"a}ttigungsindizes berechnet, sowie elektronenmikropische, porosimetrische und r{\"o}ntgenografische Untersuchungen durchgef{\"u}hrt. Abschließend wurden die Ergebnisse gesamtheitlich interpretiert, da die Ergebnisse der einzelnen Untersuchungsprogramme miteinander in Wechselwirkung stehen. Als haupts{\"a}chliche Hydratationsprodukte wurden Calciumsulfat-Dihydrat, Ettringit und C-(A)-S-H-Phasen ermittelt, deren Anteile im GZPB neben dem Calciumsulfatanteil und dem Puzzolan-Zement-Verh{\"a}ltnis auch deutlich vom Wasserangebot und der Gef{\"u}geentwicklung abh{\"a}ngen. Bei Verwendung von alumosilikatischen Puzzolans kommt es wahrscheinlich zur teilweisen Substitution des Siliciums durch Aluminium in den C-S-H-Phasen. Dies erscheint aufgrund des Nachweises der f{\"u}r diese Phasen typischen, folienartigen Morphologie wahrscheinlich. Portlandit wurde in raumbest{\"a}ndigen GZPB-Systemen nur zu sehr fr{\"u}hen Zeitpunkten in geringen Mengen gefunden. In den Untersuchungen konnte ein Teil der in der Literatur beschriebenen, prinzipiellen Hydratationsabl{\"a}ufe best{\"a}tigt werden. Bei Verwendung von Halbhydrat als Calciumsulfatkomponente entsteht zuerst Dihydrat und bildet die Prim{\"a}rstruktur der GZPB. In dieses existierende Grundgef{\"u}ge kristallisieren dann das Ettringit und die C-(A)-S-H-Phasen. In den GZPB sorgen entgegen der Beschreibungen in der Literatur nicht ausschließlich die C-(A)-S-H-Phasen zur Verbesserung der Feuchtebest{\"a}ndigkeit und der Erh{\"o}hung des Festigkeitsniveaus, sondern auch das Ettringit. Beide Phasen {\"u}berwachsen im zeitlichen Verlauf der Hydratation die Dihydratkristalle in der Matrix und h{\"u}llen diese - je nach Calciumsulfatanteil im GZPB - teilweise oder vollst{\"a}ndig ein. Diese Umh{\"u}llung sowie die starke Gef{\"u}geverdichtung durch die C-(A)-S-H-Phasen und das Ettringit bedingen, dass ein l{\"o}sender Angriff durch Wasser erschwert oder gar verhindert wird. Gleichzeitig wird die Gleitf{\"a}higkeit an den Kontaktstellen der Dihydratkristalle verringert. Eine rissfreie und raumbest{\"a}ndige Erh{\"a}rtung ist f{\"u}r die gefahrlose Anwendung eines GZPB-Systems essentiell. Hierf{\"u}r ist die Kinetik der Ettringitbildung von elementarer Bedeutung. Die gebildete Ettringitmenge spielt nur eine untergeordnete Rolle. Selbst ausgepr{\"a}gte, ettringitbedingte Dehnungen und hohe sich bildende Mengen f{\"u}hren zu fr{\"u}hen Zeitpunkten, wenn die Dihydratkristalle noch leicht gegeneinander verschiebbar sind, zu keinen Sch{\"a}den. Bleibt die {\"U}bers{\"a}ttigung bez{\"u}glich Ettringit und somit auch der Kristallisationsdruck allerdings {\"u}ber einen langen Zeitraum hoch, gen{\"u}gen bereits geringe Ettringitmengen, um das sich stetig verfestigende Gef{\"u}ge stark zu sch{\"a}digen. Die f{\"u}r die raumbest{\"a}ndige Erh{\"a}rtung der GZPB notwendige, schnelle Abnahme der Ettringit{\"u}bers{\"a}ttigung wird haupts{\"a}chlich durch die Reaktivit{\"a}t des Puzzolans beeinflusst. Die puzzolanische Reaktion f{\"u}hrt zur Bindung des aus dem Zement stammenden Calciumhydroxid durch die Bildung von C-(A)-S-H-Phasen und Ettringit. Hierdurch sinkt die Calcium- und Hydroxidionenkonzentration in der Porenl{\"o}sung im Verlauf der Hydratation, wodurch auch die {\"U}bers{\"a}ttigung bez{\"u}glich Ettringit abnimmt. Je h{\"o}her die Reaktivit{\"a}t des Puzzolans ist, desto schneller sinkt der S{\"a}ttigungsindex des Ettringits und somit auch der Kristallisationsdruck. Nach Unterschreiten eines noch n{\"a}her zu kl{\"a}rendem Grenzwert der {\"U}bers{\"a}ttigung stagnieren die Dehnungen. Das Ettringit kristallisiert bzw. w{\"a}chst nun bevorzugt in den Poren ohne eine weitere, {\"a}ußere Volumenzunahme zu verursachen. Um eine schadensfreie Erh{\"a}rtung des GZPB zu gew{\"a}hrleisten, muss gerade in der fr{\"u}hen Phase der Hydratation ein ausreichendes Wasserangebot gew{\"a}hrleistet werden, so dass die Ettringitbildung m{\"o}glichst vollst{\"a}ndig ablaufen kann. Andernfalls kann es bei einer Wiederbefeuchtung zur Reaktivierung der Ettringitbildung kommen, was im eingebauten Zustand Sch{\"a}den verursachen kann. Die Gew{\"a}hrleistung eines ausreichenden Wasserangebots ist im GZPB-System nicht unproblematisch. In Abh{\"a}ngigkeit der GZPB-Zusammensetzung k{\"o}nnen sich große Ettringitmengen bilden, die einen sehr hohen Wasserbedarf aufweisen. Deshalb kann es, je nach verwendeten Wasser-Bindemittel-Wert, im Bindemittelleim zu einem Wassermangel kommen, welcher die weitere Hydratation verlangsamt bzw. komplett verhindert. Zudem k{\"o}nnen GZPB-Systeme teils sehr dichte Gef{\"u}ge ausbilden, wodurch der Wassertransport zum Reaktionsort des Ettringits zus{\"a}tzlich behindert wird. Die Konzeption raumbest{\"a}ndiger GZPB-Systeme muss anhand mehrerer aufeinander aufbauender Untersuchungen erfolgen. Zur Vorauswahl geeigneter Puzzolan-Zementverh{\"a}ltnisse eignen sich die Messungen der CaO-Konzentration und des pH-Wertes in Suspensionen. Als alleinige Beurteilungsgrundlage reicht dies allerdings nicht aus. Zus{\"a}tzlich muss das L{\"a}ngen{\"a}nderungs-verhalten beurteilt werden. Raumbest{\"a}ndige Mischungen mit alumosilikatischen Puzzolanen zeigen zu fr{\"u}hen Zeitpunkten starke Dehnungen, welche dann abrupt stagnieren. Stetige - auch geringe - Dehnungen weisen auf eine destruktive Zusammensetzung hin. Mit diesem mehrstufigen Vorgehen k{\"o}nnen raumbest{\"a}ndige, stabile GZPB-Systeme konzipiert werden, so dass die Zielstellung der Arbeit erreicht wurde und ein sicherer praktischer Einsatz dieser Bindemittelart gew{\"a}hrleistet werden kann.  }, subject = {Gips}, language = {de} } @phdthesis{Schlaffke, author = {Schlaffke, Markus}, title = {Die Rekonstruktion des Menaka-Archivs: Navigationen durch die Tanz-Moderne zwischen Kolkata, Mumbai und Berlin 1936-38}, doi = {10.25643/bauhaus-universitaet.4706}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20220823-47069}, school = {Bauhaus-Universit{\"a}t Weimar}, abstract = {Die Europatournee des Indischen Menaka-Balletts von 1936-38 ist der Ausgangspunkt dieser archivologischen Navigation entlang der Spuren indischer K{\"u}nstlerInnen in Europa. In einer breit angelegten Archivrecherche wurden dazu Dokumente, Fundst{\"u}cke, orale Erinnerungen und ethnografische Beobachtungen aus dem Kontext der Menaka-Tournee durch das nationalsozialistische Deutschland zusammengetragen. Das Buch beschreibt den Rekonstruktionsprozess eines bedeutsamen Projekts der indischen Tanzmoderne. Es verfolgt dabei eine Methode, mit der sich die fragmentierten Dokumente des Medienereignisses als Spur lesen lassen und nutzt eine k{\"u}nstlerisch-forschende Involvierung in gegenw{\"a}rtige Erinnerungspolitiken, in welche die verflochtenen Strukturen der k{\"u}nstlerischen Avantgarde zwischen Kolkata, Mumbai und Berlin hineinreichen. Die Spur des Menaka-Ballett erweist sich dabei als Teil weitreichender ideologischer, t{\"a}nzerischer, musikalischer, filmischer und literarischer Str{\"o}mungen, die auch in gegenw{\"a}rtigen kulturellen Bestimmungen fortwirken. Fotografien, Zeitungsberichte, Film- und Tonaufnahmen, Briefe und pers{\"o}nliche Erinnerungst{\"u}cke erz{\"a}hlen davon, wie sich, vor dem Hintergrund der im antikolonialen Aufbruch befindlichen Kulturreform in Indien, und der nationsozialistisch-v{\"o}lkischen Kulturpolitik in Deutschland, die T{\"a}nzerinnen und Musiker der indischen Ballettgruppe und die deutsche {\"O}ffentlichkeit im gegenseitigen Spiegel betrachteten, w{\"a}hrend die Vorzeichen des kommenden Krieges immer deutlicher wurden.}, subject = {Menaka }, language = {de} } @phdthesis{ShaabanMohamed, author = {Shaaban Mohamed, Ahmed Mostafa}, title = {Isogeometric boundary element analysis and structural shape optimization for Helmholtz acoustic problems}, doi = {10.25643/bauhaus-universitaet.4703}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20220816-47030}, school = {Bauhaus-Universit{\"a}t Weimar}, abstract = {In this thesis, a new approach is developed for applications of shape optimization on the time harmonic wave propagation (Helmholtz equation) for acoustic problems. This approach is introduced for different dimensional problems: 2D, 3D axi-symmetric and fully 3D problems. The boundary element method (BEM) is coupled with the isogeometric analysis (IGA) forming the so-called (IGABEM) which speeds up meshing and gives higher accuracy in comparison with standard BEM. BEM is superior for handling unbounded domains by modeling only the inner boundaries and avoiding the truncation error, present in the finite element method (FEM) since BEM solutions satisfy the Sommerfeld radiation condition automatically. Moreover, BEM reduces the space dimension by one from a volumetric three-dimensional problem to a surface two-dimensional problem, or from a surface two-dimensional problem to a perimeter one-dimensional problem. Non-uniform rational B-splines basis functions (NURBS) are used in an isogeometric setting to describe both the CAD geometries and the physical fields. IGABEM is coupled with one of the gradient-free optimization methods, the Particle Swarm Optimization (PSO) for structural shape optimization problems. PSO is a straightforward method since it does not require any sensitivity analysis but it has some trade-offs with regard to the computational cost. Coupling IGA with optimization problems enables the NURBS basis functions to represent the three models: shape design, analysis and optimization models, by a definition of a set of control points to be the control variables and the optimization parameters as well which enables an easy transition between the three models. Acoustic shape optimization for various frequencies in different mediums is performed with PSO and the results are compared with the benchmark solutions from the literature for different dimensional problems proving the efficiency of the proposed approach with the following remarks: - In 2D problems, two BEM methods are used: the conventional isogeometric boundary element method (IGABEM) and the eXtended IGABEM (XIBEM) enriched with the partition-of-unity expansion using a set of plane waves, where the results are generally in good agreement with the linterature with some computation advantage to XIBEM which allows coarser meshes. -In 3D axi-symmetric problems, the three-dimensional problem is simplified in BEM from a surface integral to a combination of two 1D integrals. The first is the line integral similar to a two-dimensional BEM problem. The second integral is performed over the angle of revolution. The discretization is applied only to the former integration. This leads to significant computational savings and, consequently, better treatment for higher frequencies over the full three-dimensional models. - In fully 3D problems, a detailed comparison between two BEM methods: the conventional boundary integral equation (CBIE) and Burton-Miller (BM) is provided including the computational cost. The proposed models are enhanced with a modified collocation scheme with offsets to Greville abscissae to avoid placing collocation points at the corners. Placing collocation points on smooth surface enables accurate evaluation of normals for BM formulation in addition to straightforward prediction of jump-terms and avoids singularities in \$\mathcal{O} (1/r)\$ integrals eliminating the need for polar integration. Furthermore, no additional special treatment is required for the hyper-singular integral while collocating on highly distorted elements, such as those containing sphere poles. The obtained results indicate that, CBIE with PSO is a feasible alternative (except for a small number of fictitious frequencies) which is easier to implement. Furthermore, BM presents an outstanding treatment of the complicated geometry of mufflers with internal extended inlet/outlet tube as an interior 3D Helmholtz acoustic problem instead of using mixed or dual BEM.}, subject = {Randelemente-Methode}, language = {en} } @article{PatzeltErfurtLudwig, author = {Patzelt, Max and Erfurt, Doreen and Ludwig, Horst-Michael}, title = {Quantification of cracks in concrete thin sections considering current methods of image analysis}, series = {Journal of Microscopy}, volume = {2022}, journal = {Journal of Microscopy}, number = {Volume 286, Issue 2}, doi = {10.1111/jmi.13091}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20220811-46754}, pages = {154 -- 159}, abstract = {Image analysis is used in this work to quantify cracks in concrete thin sections via modern image processing. Thin sections were impregnated with a yellow epoxy resin, to increase the contrast between voids and other phases of the concrete. By the means of different steps of pre-processing, machine learning and python scripts, cracks can be quantified in an area of up to 40 cm2. As a result, the crack area, lengths and widths were estimated automatically within a single workflow. Crack patterns caused by freeze-thaw damages were investigated. To compare the inner degradation of the investigated thin sections, the crack density was used. Cracks in the thin sections were measured manually in two different ways for validation of the automatic determined results. On the one hand, the presented work shows that the width of cracks can be determined pixelwise, thus providing the plot of a width distribution. On the other hand, the automatically measured crack length differs in comparison to the manually measured ones.}, subject = {Beton}, language = {en} } @article{GuoZhuangChenetal., author = {Guo, Hongwei and Zhuang, Xiaoying and Chen, Pengwan and Alajlan, Naif and Rabczuk, Timon}, title = {Analysis of three-dimensional potential problems in non-homogeneous media with physics-informed deep collocation method using material transfer learning and sensitivity analysis}, series = {Engineering with Computers}, volume = {2022}, journal = {Engineering with Computers}, doi = {10.1007/s00366-022-01633-6}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20220811-46764}, pages = {1 -- 22}, abstract = {In this work, we present a deep collocation method (DCM) for three-dimensional potential problems in non-homogeneous media. This approach utilizes a physics-informed neural network with material transfer learning reducing the solution of the non-homogeneous partial differential equations to an optimization problem. We tested different configurations of the physics-informed neural network including smooth activation functions, sampling methods for collocation points generation and combined optimizers. A material transfer learning technique is utilized for non-homogeneous media with different material gradations and parameters, which enhance the generality and robustness of the proposed method. In order to identify the most influential parameters of the network configuration, we carried out a global sensitivity analysis. Finally, we provide a convergence proof of our DCM. The approach is validated through several benchmark problems, also testing different material variations.}, subject = {Deep learning}, language = {en} } @article{ChakrabortyAnitescuZhuangetal., author = {Chakraborty, Ayan and Anitescu, Cosmin and Zhuang, Xiaoying and Rabczuk, Timon}, title = {Domain adaptation based transfer learning approach for solving PDEs on complex geometries}, series = {Engineering with Computers}, volume = {2022}, journal = {Engineering with Computers}, doi = {10.1007/s00366-022-01661-2}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20220811-46776}, pages = {1 -- 20}, abstract = {In machine learning, if the training data is independently and identically distributed as the test data then a trained model can make an accurate predictions for new samples of data. Conventional machine learning has a strong dependence on massive amounts of training data which are domain specific to understand their latent patterns. In contrast, Domain adaptation and Transfer learning methods are sub-fields within machine learning that are concerned with solving the inescapable problem of insufficient training data by relaxing the domain dependence hypothesis. In this contribution, this issue has been addressed and by making a novel combination of both the methods we develop a computationally efficient and practical algorithm to solve boundary value problems based on nonlinear partial differential equations. We adopt a meshfree analysis framework to integrate the prevailing geometric modelling techniques based on NURBS and present an enhanced deep collocation approach that also plays an important role in the accuracy of solutions. We start with a brief introduction on how these methods expand upon this framework. We observe an excellent agreement between these methods and have shown that how fine-tuning a pre-trained network to a specialized domain may lead to an outstanding performance compare to the existing ones. As proof of concept, we illustrate the performance of our proposed model on several benchmark problems.}, subject = {Maschinelles Lernen}, language = {en} } @article{RoskammVollmer, author = {Roskamm, Nikolai and Vollmer, Lisa}, title = {Was ist Stadt? Was ist Kritik? Einf{\"u}hrung in die Debatte zum Jubil{\"a}umsheft von sub\urban}, series = {sub\urban. zeitschrift f{\"u}r kritische stadtforschung}, journal = {sub\urban. zeitschrift f{\"u}r kritische stadtforschung}, number = {Band 10, Nr. 1,}, publisher = {Sub\urban e.V.}, address = {Leipzig}, doi = {10.36900/suburban.v10i1.798}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20220811-46847}, pages = {127 -- 130}, abstract = {Im Heft zum zehnj{\"a}hrigen Jubil{\"a}um von sub\urban mit dem Themenschwerpunkt „sub\x: Verortungen, Entortungen" ver{\"o}ffentlichen wir eine Debatte, die von den bisherigen in unserer Zeitschrift in dieser Rubrik gef{\"u}hrten textlichen Diskussionen abweicht. Im Vorfeld der Planungen f{\"u}r unsere Jubil{\"a}umsausgabe haben wir die aktuellen Mitglieder unseres wissenschaftlichen Beirats darum gebeten, zwei grundlegende Fragen von kritischer Stadtforschung in kurzen Beitr{\"a}gen zu diskutieren: Was ist Stadt? Was ist Kritik?}, subject = {Stadt}, language = {de} } @article{WelchGuerra, author = {Welch Guerra, Max}, title = {Fach, Gesellschaft und Wissenschaft. Beitrag zur Debatte „Was ist Stadt? Was ist Kritik?"}, series = {sub\urban. zeitschrift f{\"u}r kritische stadtforschung}, volume = {2022}, journal = {sub\urban. zeitschrift f{\"u}r kritische stadtforschung}, number = {Band 10, Nr. 1}, publisher = {Sub\urban e.V.}, address = {Leipzig}, doi = {10.36900/suburban.v10i1.779}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20220810-46855}, pages = {188 -- 190}, abstract = {Der Aufruf, die Begriffe Stadt und Kritik in das Zentrum einer Debatte zu stellen, bietet die große Chance, uns weit {\"u}ber begriffliche Kl{\"a}rungen unseres gemeinsamen Arbeitsgegenstands hinaus - die ja auch f{\"u}r sich selbst sehr fruchtbar sein k{\"o}nnen - {\"u}ber die Funktion zu verst{\"a}ndigen, die wir in der Gesellschaft aus{\"u}ben, wenn wir r{\"a}umliche Planung praktizieren, erforschen und lehren. Da in der Bundesrepublik nicht nur ein großer Bedarf, sondern auch eine betr{\"a}chtliche Nachfrage nach {\"o}ffentlicher Planung besteht und die planungsbezogenen Wissenschaften sich eines insgesamt stabilen institutionellen Standes erfreuen, laufen wir Gefahr, die gesellschaftspolitische Legitimation von Berufsfeld und Wissenschaft zu vernachl{\"a}ssigen, sie als gegeben zu behandeln. Wir m{\"u}ssen uns ja kaum rechtfertigen.}, subject = {Stadt}, language = {de} }