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- OA-Publikationsfonds2023 (14) (remove)
The study presents a Machine Learning (ML)-based framework designed to forecast the stress-strain relationship of arc-direct energy deposited mild steel. Based on microstructural characteristics previously extracted using microscopy and X-ray diffraction, approximately 1000 new parameter sets are generated by applying the Latin Hypercube Sampling Method (LHSM). For each parameter set, a Representative Volume Element (RVE) is synthetically created via Voronoi Tessellation. Input raw data for ML-based algorithms comprises these parameter sets or RVE-images, while output raw data includes their corresponding stress-strain relationships calculated after a Finite Element (FE) procedure. Input data undergoes preprocessing involving standardization, feature selection, and image resizing. Similarly, the stress-strain curves, initially unsuitable for training traditional ML algorithms, are preprocessed using cubic splines and occasionally Principal Component Analysis (PCA). The later part of the study focuses on employing multiple ML algorithms, utilizing two main models. The first model predicts stress-strain curves based on microstructural parameters, while the second model does so solely from RVE images. The most accurate prediction yields a Root Mean Squared Error of around 5 MPa, approximately 1% of the yield stress. This outcome suggests that ML models offer precise and efficient methods for characterizing dual-phase steels, establishing a framework for accurate results in material analysis.
When predicting sound pressure levels induced by structure-borne sound sources and describing the sound propagation path through the building structure as exactly as possible, it is necessary to characterize the vibration behavior of the structure-borne sound sources. In this investigation, the characterization of structure-borne sound sources was performed using the two-stage method (TSM) described in EN 15657. Four different structure-borne sound sources were characterized and subsequently installed in a lightweight test stand. The resulting sound pressure levels in an adjacent receiving room were measured. In the second step, sound pressure levels were predicted according to EN 12354-5 based on the parameters of the structure-borne sound sources. Subsequently, the predicted and the measured sound pressure levels were compared to obtain reliable statements on the achievable accuracy when using source quantities determined by TSM with this prediction method.
The imperative to transform current energy provisions is widely acknowledged. However, scant attention has hitherto been directed toward rural municipalities and their innate resources, notably biogenic resources. In this paper, a methodological framework is developed to interconnect resources from waste, wastewater, and agricultural domains for energy utilization. This entails cataloging existing resources, delineating their potential via quantitative assessments utilizing diverse technologies, and encapsulating them in a conceptual model. The formulated models underwent iterative evaluation with engagement from diverse stakeholders. Consequently, 3 main concepts, complemented by 72 sub-concepts, were delineated, all fostering positive contributions to climate protection and providing heat supply in the rural study area. The outcomes’ replicability is underscored by the study area’s generic structure and the employed methodology. Through these inquiries, a framework for the requisite energy transition, with a pronounced emphasis on the coupling of waste, wastewater, and agriculture sectors in rural environments, is robustly analyzed.
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.
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.
Die Planungsforschung hat sich spätestens seit der „kommunikativen Wende“ intensiv damit beschäftigt, wie mit Konflikten umgegangen werden soll und wird. Ansätze der „agonistischen“ Planungstheorie widersprechen der normativen Prämisse, Konsensbildung unter den Planungsbeteiligten anzustreben. Vielmehr wollen sie widerstreitende Positionen normativ für die räumliche Entwicklung fruchtbar machen. Zugleich betonen sie eine vermeintliche Dualität von Planung und Protest, die in der neueren Protesttheorie infrage gestellt wird. Dieser Beitrag zeigt aufbauend auf einer Diskussion von planungs- und protesttheoretischen Ansätzen und einer empirischen Analyse planungsbezogener Proteste in Deutschland, dass diese Proteste von den Planungsakteuren zwar immer stärker als „Normalität“ aufgefasst werden und antagonistische Partizipation trotz zunehmender Konflikthaftigkeit und vermeintlicher Infragestellung der repräsentativen Demokratie kulturell regelgebunden bleibt. Protesthandeln ist Teil ausdifferenzierter „Partizipationsbündel“, die situationsbezogen auch Teilnahme an Beteiligungsverfahren, direktdemokratische Verfahren und Klagen umfassen. Protestierende verfolgen dabei meist eine eher reformorientierte Agenda, die keiner „Zähmung“ bedarf. Allerdings können die zugrunde liegenden Konflikte häufig gar nicht „gelöst“ werden. Planenden hingegen können auch innerhalb eines agonistischen Planungsumfelds rationalistische und deliberative Ansätze zur Verfügung stehen, die sie situationsbezogen und strategisch nutzen.
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.
Patterns of Detachment: Spatial Transformations of the Phosphate Industry in el-Quseir, Egypt
(2023)
The establishment of phosphate mines and processing plants by Italian entrepreneurs in el-Quseir in 1912 revitalized a town that had faced a steady decline after the opening of the Suez Canal and re-linked it to the world economy. To this day, the now defunct industrial site occupies a large section of physical el-Quseir and plays a key role in its identity. In this article, we explore the impact of the company’s successive industrialization and deindustrialization based on archival research, interviews, and mapping. By tracing physical changes on-site and in the city of el-Quseir from the founding of its phosphate industry until today, as well as the historical and current interactions of citizens with the industrial facilities, we hope to better understand the “cluster value” of the industrial plant in quotidian life and the effect of the vacuum left behind after the termination of production. As machinery and buildings are slowly eroding in the absence of expressed interest by the former Italian and current Egyptian owners, we aim to discuss the relationship between the citizens and their el-Quseir phosphate plant as a crucial element of its heritage value at the local level.
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.
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.
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