TY - JOUR A1 - Wiegand, Torben A1 - Osburg, Andrea T1 - Synthesis, Curing and Thermal Behavior of Amine Hardeners from Potentially Renewable Sources JF - Polymers N2 - Research into bio-based epoxy resins has intensified in recent decades. Here, it is of great importance to use raw materials whose use does not compete with food production. In addition, the performance of the newly developed materials should be comparable to that of conventional products. Possible starting materials are lignin degradation products, such as vanillin and syringaldehyde, for which new synthesis routes to the desired products must be found and their properties determined. In this article, the first synthesis of two amine hardeners, starting with vanillin and syringaldehyde, using the Smiles rearrangement reaction is reported. The amine hardeners were mixed with bisphenol A diglycidyl ether, and the curing was compared to isophorone diamine, 4-4′-diaminodiphenyl sulfone, and 4-Aminonbenzylamine by means of differential scanning calorimetry. It was found that the two amines prepared are cold-curing. As TG-MS studies showed, the thermal stability of at least one of the polymers prepared with the potentially bio-based amines is comparable to that of the polymer prepared with isophorone diamine, and similar degradation products are formed during pyrolysis. KW - Epoxide KW - Epoxidharz KW - Polymere KW - epoxy KW - amine hardener KW - curing agent KW - bio-based KW - vanillin KW - OA-Publikationsfonds2023 Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20230524-63745 UR - https://www.mdpi.com/2073-4360/15/4/990 VL - 2023 IS - volume 15, issue 4, article 990 SP - 1 EP - 12 PB - MDPI CY - Basel ER - TY - JOUR A1 - Partschefeld, Stephan A1 - Tutal, Adrian A1 - Halmanseder, Thomas A1 - Schneider, Jens A1 - Osburg, Andrea T1 - Investigations on Stability of Polycarboxylate Superplasticizers in Alkaline Activators for Geopolymer Binders JF - Materials N2 - Calcined clays are interesting starting materials to be used as SCMs (supplementary cementitious materials) in cements or to be converted to geopolymers by activation with a high alkaline activator. The adjustment of the properties in the fresh state, especially regarding the consistency of these binders, is almost exclusively achieved by the addition of water, since commercially available superplasticizers seem to be ineffective in low-calcium geopolymer systems. The aim of this study was a systematic investigation of various PCE (polycarboxylate ester/ether) superplasticizers (methacrylate ester PCE: MPEG, isoprenol ether PCE: IPEG, methallyl ether PCE: HPEG) with respect to their stability in different alkaline activators (NaOH, KOH, sodium and potassium silicate solutions). The effectiveness of superplasticizers (SPs) in low-calcium geopolymer binders was verified by rheological tests. Size exclusion chromatography was used to investigate if structural degradation of the superplasticizers occurs. The investigated PCE superplasticizers showed a thickening effect in the low-calcium geopolymer system. Depending on the alkalinity of the activator solution, a degradation process was detected for all the PCEs investigated. The side chains of the PCEs are cleaved off the backbone by basic ester and ether hydrolysis. The highest degree of degradation was found in sodium and potassium silicate solutions. In alkaline hydroxide solutions, the degradation process increases with increasing alkalinity. KW - Geopolymere KW - Verflüssigung KW - metakaoline KW - superplasticizer KW - polycarboxylate ether KW - OA-Publikationsfonds2023 Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20231026-64809 UR - https://www.mdpi.com/1996-1944/16/15/5369 VL - 2023 IS - Volume 16, issue 15, article 5369 SP - 1 EP - 14 PB - MDPI CY - Basel ER - TY - JOUR A1 - Alsaad, Hayder A1 - Schälte, Gereon A1 - Schneeweiß, Mario A1 - Becher, Lia A1 - Pollack, Moritz A1 - Gena, Amayu Wakoya A1 - Schweiker, Marcel A1 - Hartmann, Maria A1 - Voelker, Conrad A1 - Rossaint, Rolf A1 - Irrgang, Matthias T1 - The Spread of Exhaled Air and Aerosols during Physical Exercise JF - Journal of Clinical Medicine N2 - Physical exercise demonstrates a special case of aerosol emission due to its associated elevated breathing rate. This can lead to a faster spread of airborne viruses and respiratory diseases. Therefore, this study investigates cross-infection risk during training. Twelve human subjects exercised on a cycle ergometer under three mask scenarios: no mask, surgical mask, and FFP2 mask. The emitted aerosols were measured in a grey room with a measurement setup equipped with an optical particle sensor. The spread of expired air was qualitatively and quantitatively assessed using schlieren imaging. Moreover, user satisfaction surveys were conducted to evaluate the comfort of wearing face masks during training. The results indicated that both surgical and FFP2 masks significantly reduced particles emission with a reduction efficiency of 87.1% and 91.3% of all particle sizes, respectively. However, compared to surgical masks, FFP2 masks provided a nearly tenfold greater reduction of the particle size range with long residence time in the air (0.3–0.5 μm). Furthermore, the investigated masks reduced exhalation spreading distances to less than 0.15 m and 0.1 m in the case of the surgical mask and FFP2 mask, respectively. User satisfaction solely differed with respect to perceived dyspnea between no mask and FFP2 mask conditions. KW - Sport KW - Training KW - Fahrradergometer KW - sport KW - training KW - cycle ergometer KW - schlieren imaging KW - particles concentration KW - OA-Publikationsfonds2023 Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20230208-49262 UR - https://www.mdpi.com/2077-0383/12/4/1300 VL - 2023 IS - Volume 12, issue 4, article 1300 PB - Basel CY - MDPI ER - TY - JOUR A1 - Brokow-Loga, Anton A1 - Krüger, Timmo T1 - Potentials of Climate Emergency Declarations for degrowth transformations. The ambivalent stance of German municipalities in conflicts over a post-fossil future JF - Raumforschung und Raumordnung N2 - This paper addresses the scope for action by municipalities in a climate emergency and places it in the framework of ecomodern (urban) policy. We analyse the way in which two German ‘climate emergency municipalities’ translate conflicts of post-fossil transformation into concrete political and planning strategies. Although more than 2,200 authorities around the world have already declared a climate emergency, research on the impact of these resolutions on the political orientation of municipalities is very limited. Our research focus is on the (potentially agonistic) treatment of conflicts in planning. We argue that in times of a socio-ecological crisis, success in conflict resolution cannot refer to appeasement and depoliticisation. Instead, we propose a framework of five criteria, based on critical theory on ecomodern strategies, planning processes and degrowth. Thus, this practice-related and explorative paper connects empirical insights from the German cities of Constance and Berlin with an innovative normative framework. The findings tell a complex story of an, at least partial, admission of the failure of previous climate mitigation strategies, a lack of social institutions of limits, an instrumental relation to nature and a disregard for social injustices. The paper discusses how municipalities, in the context of ongoing tensions over the post-fossil transformation in Germany, on the one hand hold on to business-as-usual approaches, but on the other hand also set political impulses for change. KW - Stadtentwicklung KW - Wachstumskritik KW - Klimanotstand KW - Degrowth KW - Postwachstum KW - Postwachstumsstadt KW - OA-Publikationsfonds2023 Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20231204-64984 UR - https://rur.oekom.de/index.php/rur/article/view/1666 VL - 2023 IS - Vol. 81, No. 5 SP - 523 EP - 537 PB - oekom Verlag CY - München ER - TY - BOOK A1 - Siegler, Martin T1 - SOS: Medien des Überlebens. Die existenzielle Bedeutung von Lebenszeichen in Notfällen N2 - SOS-Signale auf hoher See, Klopfzeichen in Trümmerfeldern, Flaschenposten am Strand: Wenn Menschen in Not geraten, müssen sie mit allen Mitteln auf sich aufmerksam machen. Sie müssen Lebenszeichen senden, um am Leben zu bleiben. Dieses Buch erforscht das Phänomen des Lebenszeichens erstmals aus der Perspektive von Medienkulturwissenschaft, Zeichentheorie und Existenzphilosophie. Anhand zahlreicher Katastrophenszenarien wie Erdbeben, Lawinen und Bergwerkunglücken zeigt die Studie, warum Menschen in Not existenziell von Medien und Kommunikationsmitteln abhängen: Keine Lebenszeichen ohne Signalfackeln, Peilsender, Satelliten oder Infrarotsensoren. Medien in Notfällen sind mehr als nur Mittel zur Kommunikation, sie sind Bedingungen menschlicher Existenz. Sie entscheiden, ob und wie sich Leben in Not äußern kann, ob Lebenszeichen Gehör finden und ob Leben gerettet wird. Damit werfen Lebenszeichen ein neues Licht auf die elementaren Bedingungen menschlichen Lebens: Sie zeigen uns, dass Menschen in Not nur überleben, wenn sie mit Artefakten, Netzwerken und Infrastrukturen verbunden sind, die ihre Existenz ermöglichen. KW - Medien KW - Notfall KW - Medienphilosophie KW - Lebenszeichen KW - Notfall KW - Katastrophenfall KW - Kommunikationsmittel KW - Medien KW - OA-Publikationsfonds2023 Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20231026-64816 UR - https://www.degruyter.com/document/doi/10.1515/9783111075341/html SN - 978-3-11-107534-1 PB - De Gruyter CY - Berlin ER - TY - JOUR A1 - Bapir, Baban A1 - Abrahamczyk, Lars A1 - Wichtmann, Torsten A1 - Prada-Sarmiento, Luis Felipe ED - Ozturk, Baki T1 - Soil-structure interaction: A state-of-the-art review of modeling techniques and studies on seismic response of building structures JF - Frontiers in Built Environment N2 - The present article aims to provide an overview of the consequences of dynamic soil-structure interaction (SSI) on building structures and the available modelling techniques to resolve SSI problems. The role of SSI has been traditionally considered beneficial to the response of structures. However, contemporary studies and evidence from past earthquakes showed detrimental effects of SSI in certain conditions. An overview of the related investigations and findings is presented and discussed in this article. Additionally, the main approaches to evaluate seismic soil-structure interaction problems with the commonly used modelling techniques and computational methods are highlighted. The strength, limitations, and application cases of each model are also discussed and compared. Moreover, the role of SSI in various design codes and global guidelines is summarized. Finally, the advancements and recent findings on the SSI effects on the seismic response of buildings with different structural systems and foundation types are presented. In addition, with the aim of helping new researchers to improve previous findings, the research gaps and future research tendencies in the SSI field are pointed out. KW - Boden-Bauwerk-Wechselwirkung KW - Bautechnik KW - Erdbeben KW - Grundlage KW - soil-structure interaction KW - structural engineering KW - earthquake engineering KW - foundations KW - OA-Publikationsfonds2023 Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20230206-49190 UR - https://www.frontiersin.org/articles/10.3389/fbuil.2023.1120351/full VL - 2023 IS - Volume 9 SP - 1 EP - 17 PB - Frontiers Media CY - Lausanne ER - TY - JOUR A1 - Londong, Jörg A1 - Barth, Marcus A1 - Söbke, Heinrich T1 - Reducing antimicrobial resistances by source separation of domestic wastewater JF - Frontiers in Environmental Health N2 - Antimicrobial resistances (AMR) are ranked among the top ten threats to public health and societal development worldwide. Toilet wastewater contained in domestic wastewater is a significant source of AMR entering the aquatic environment. The current commonly implemented combined sewer systems at times cause overflows during rain events, resulting in the discharge of untreated wastewater into the aquatic environment, thus promoting AMR. In this short research article, we describe an approach to transform combined sewer systems into source separation-modified combined sewer systems that separately treat toilet wastewater. We employ simulations for demonstrating that source separation-modified combined sewer systems reduce the emission of AMR- causing substances by up to 11.5 logarithm levels. Thus, source separation- modified combined sewer systems are amongst the most effective means of combating AMR. KEYWORDS KW - Allgemeinheit KW - Öffentlichkeit KW - Gesundheit KW - Kanal KW - Abwasser KW - Antibiotikum KW - Resistenz KW - OA-Publikationsfonds2023 Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20230403-49483 UR - https://www.frontiersin.org/articles/10.3389/fenvh.2023.1151898/full VL - 2023 IS - Volume 2, article 1151898 SP - 1 EP - 5 PB - Frontiers Media CY - Lausanne ER - TY - JOUR A1 - Sander, Hendrik A1 - Weißermel, Sören T1 - Urban Heat Transition in Berlin: Corporate Strategies, Political Conflicts, and Just Solutions JF - Urban Planning N2 - In the field of urban climate policy, heat production and demand are key sectors for achieving a sustainable city. Heat production has to shift from fossil to renewable energies, and the heat demand of most buildings has to be reduced significantly via building retrofits. However, analyses of heat transition still lack its contextualization within entangled urban politico-economic processes and materialities and require critical socio-theoretical examination. Asking about the embeddedness of heat transition within social relations and its implications for social justice issues, this article discusses the challenges and opportunities of heat transition, taking Berlin as an example. It uses an urban political ecology perspective to analyze the materialities of Berlin’s heating-housing nexus, its politico-economic context, implications for relations of inequality and power, and its contested strategies. The empirical analysis identifies major disputes about the future trajectory of heat production and about the distribution of retrofit costs. Using our conceptual approach, we discuss these empirical findings against the idea of a more just heat transition. For this purpose, we discuss three policy proposals regarding cost distribution, urban heat planning, and remunicipalization of heat utilities. We argue that this conceptual approach provides huge benefits for debates around heat transition and, more generally, energy justice and just transitions. KW - Berlin KW - Stadtplanung KW - Ökologie KW - energy justice KW - energy retrofitting KW - green gentrification KW - low-carbon policy KW - urban political ecology KW - OA-Publikationsfonds2023 Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20230524-63845 UR - https://www.cogitatiopress.com/urbanplanning/article/view/6178 VL - 2023 IS - Volume 8, No 1 SP - 361 EP - 371 PB - Cogitatio Press CY - Lissabon ER - TY - JOUR A1 - Bockelmann, Leo T1 - Impacts of Change: Analysing the Perception of Industrial Heritage in the Vogtland Region JF - Urban Planning N2 - Beyond metropolitan areas, many peripheral regions and their cities in Europe have, in manifold ways, been significantly shaped by industrialisation. In the context of the relocation of industrial production to other countries over the last decades, the question has been raised as to the role this heritage can play in futural regional development as well as the potential local identification with this history. Hence, this article seeks to analyse the perception of the industrial heritage in the Vogtland region, located alongside the border of three German federal states and the Czech Republic. It inquires as to the perception of the industrial heritage by the local population and related potential future narrations. Based on spontaneous and explorative interviews with local people as an empirical base, a discrepancy between the perception of the tangible and intangible dimensions of the industrial heritage can be observed. On the one hand, the tangible heritage like older factories and production complexes are seen as a functional legacy and an “eyesore” narrative is attributed to them. On the other hand, people often reference the personal and familial connection to the industry and highlight its importance for the historical development and the wealth of the region. But these positive associations are mainly limited to the intangible dimension and are disconnected from the material artefacts of industrial production. KW - Vogtland KW - Technisches Denkmal KW - Regionalentwicklung KW - industrial heritage KW - perception KW - regional development KW - OA-Publikationsfonds2023 Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20230524-63814 UR - https://www.cogitatiopress.com/urbanplanning/article/view/6025 VL - 2023 IS - Volume 8, No 1 SP - 30 EP - 38 PB - Cogitatio Press CY - Lissabon ER - TY - JOUR A1 - Abrahamczyk, Lars A1 - Uzair, Aanis T1 - On the use of climate models for estimating the non-stationary characteristic values of climatic actions in civil engineering practice JF - Frontiers in Built Environment N2 - The characteristic values of climatic actions in current structural design codes are based on a specified probability of exceedance during the design working life of a structure. These values are traditionally determined from the past observation data under a stationary climate assumption. However, this assumption becomes invalid in the context of climate change, where the frequency and intensity of climatic extremes varies with respect to time. This paper presents a methodology to calculate the non-stationary characteristic values using state of the art climate model projections. The non-stationary characteristic values are calculated in compliance with the requirements of structural design codes by forming quasi-stationary windows of the entire bias-corrected climate model data. Three approaches for the calculation of non-stationary characteristic values considering the design working life of a structure are compared and their consequences on exceedance probability are discussed. KW - Klimaänderung KW - Bauwerk KW - climate change KW - climate models KW - extreme value analysis KW - characteristic value KW - OA-Publikationsfonds2023 Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20230524-63751 UR - https://www.frontiersin.org/articles/10.3389/fbuil.2023.1108328/full VL - 2023 IS - volume 9, article 1108328 SP - 1 EP - 9 PB - Frontier Media CY - Lausanne ER -