@phdthesis{Bartholome2015, author = {Bartholom{\´e}, Susanne}, title = {Grundlegende Untersuchungen zu strukturierten Blechen in Stahlleichtbautr{\"a}gern}, issn = {1611-5023}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-36375}, school = {BTU Cottbus - Senftenberg}, year = {2015}, abstract = {Im Rahmen des Forschungsprojektes werden Fragestellungen des Stahlleichtbaus bez{\"u}glich des Einsatzes von strukturierten Blechen hinterfragt, untersucht und L{\"o}sungen vorgestellt. Als Anwendungsbeispiel werden in dieser Arbeit geschweißte I-Tr{\"a}ger mit schlanken, strukturierten Stegen untersucht. Eine Serie von Blechtr{\"a}gern mit verschiedenen Stegausf{\"u}hrungen - eben, profiliert und strukturiert - wird modelliert und auf ihre Schubtragf{\"a}higkeit untersucht. Die vorliegende Arbeit beschreibt erste Untersuchungen zu strukturierten Blechen mit aktuellen numerischen Analysen und praktischen Versuchen zum globalen und lokalen Beulen. In Versuchen und numerischen Simulationen werden verschiedenste geschweißte Stahlleichtbautr{\"a}ger untersucht. Es wird erkundet, inwiefern sich das Beulverhalten von Tr{\"a}gern mit strukturierten Stegen gegen{\"u}ber ebenen oder profilierten Stegen ver{\"a}ndert. Außerdem wird definiert, welche Strukturen sich am besten f{\"u}r den Einsatz in Stahlleichtbautr{\"a}gern eignen. Schließlich wird ein Vergleich von numerischen und analytischen Versuchsergebnissen aufgezeigt und ein Berechnungsvorschlag gegeben, welcher dazu dient, Stahlleichtbautr{\"a}ger mit strukturierten Blechen bemessen zu k{\"o}nnen.}, subject = {Strukturierte Bleche; Stahlleichtbautr{\"a}ger; Beulen; Schubtragf{\"a}higkeit; Structured sheet metal; Light weight steel structures; Buckling; Shear; Strukturiertes Blech; Steg ; Tragf{\"a}higkeit; Bemessung}, language = {de} } @book{BeckerFuhrmannNagler2015, author = {Becker, Carlo W. and Fuhrmann, Christine and Nagler, Heinz}, title = {Gutachten Baukultur in l{\"a}ndlichen R{\"a}umen Brandenburgs}, isbn = {978-3-940471-36-9}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-42780}, publisher = {BTU Cottbus - Senftenberg}, year = {2015}, abstract = {Baukultur in l{\"a}ndlichen R{\"a}umen ist Alltagsbaukultur, die von vielen Akteuren mitgepr{\"a}gt wird. Ein großer Teil der Verantwortung f{\"u}r das baukulturelle Erscheinungsbild liegt auf kommunaler und regionaler Ebene. Baukultur in l{\"a}ndlichen R{\"a}umen kann nicht allein auf das Thema regionstypisches und historisches Bauen reduziert werden und bezieht sich nicht nur auf die Architektur des Geb{\"a}udes. Das baukulturelle Leitbild ist weiter gefasst und bezieht die Infrastruktur, die {\"o}ffentlichen R{\"a}ume sowie die Kulturlandschaft mit ein. Baukultur im l{\"a}ndlichen Raum ist ein Gemeinschaftswerk Vieler. Um das landesweite Spektrum widerzuspiegeln, wurden Praxisbeispiele aus Kleinst{\"a}dten (max. 10.000 Einwohner) und D{\"o}rfern aus unterschiedlichen Regionen Brandenburgs untersucht. Im Fokus der Betrachtung steht vor allem die Alltagsbaukultur. Von Interesse sind alle strategischen, planerischen und prozessuale Ans{\"a}tze, die sich ums Planen und Bauen in l{\"a}ndlichen R{\"a}umen drehen und f{\"u}r die zuk{\"u}nftige Entwicklung von Leitbildern, Methoden und Verfahren von Bedeutung sein k{\"o}nnten. Zielsetzung der Untersuchung ist die Erarbeitung eines Leitfadens f{\"u}r die St{\"a}rkung der Baukultur im l{\"a}ndlichen Raum. Die Zielgruppe des Leitfadens sind die Akteure der Baukultur in kleineren St{\"a}dten und Kommunen der l{\"a}ndlichen Regionen Brandenburgs. Der Leitfaden soll jedoch nicht nur als Dokumentation der Ergebnisse dienen. Der Schwerpunkt wird darin liegen, den Prozess aufzuzeigen, der zu einer gelungenen Baukultur gef{\"u}hrt hat. Welche Akteurs- und Tr{\"a}gerkonstellationen, welche Instrumente, rechtliche Grundlagen, Beteiligungsverfahren oder Finanzierung sind bei der Umsetzung zur Anwendung gekommen und k{\"o}nnen anderen Kommunen als Vorbild dienen?}, subject = {Baukultur; Brandenburg; L{\"a}ndlicher Raum; Kleinstadt; Architektur; Bautenschutz; Beispielsammlung}, language = {de} } @phdthesis{Paetsch2017, author = {P{\"a}tsch, Carolin}, title = {The capacity of institutional innovation following the diffusion of urban plans. Explorations of impacts of an urban master plan in Kigali, Rwanda.}, isbn = {978-3-00-057610-2}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-43537}, school = {BTU Cottbus - Senftenberg}, year = {2017}, abstract = {In the breeding ground of urban growth, master plans are reinvigorating around the world and gain special consideration in African countries. Most of the time urban master plans are developed by mandated (international) firms, which transfer urban design scheme ideas or strategic instruments out of their planning practice. Although this process is common in everyday planning practice, there is a lack of knowledge about the consequences of such planning processes. The case of Kigali - the capital of Rwanda — reflects these urban planning phenomena. The political will and planning efforts in Kigali for urbanisation are big. City officials are constantly renewing planning policies as well as institutions and have commissioned Surbana International Consultants Pte Ltd from Singapore to develop the city's Detailed Master Plan (2011-2013). My research, therefore, discusses institutional innovation (the amount and the extent) in Kigali, resulting from its Detailed Master Plan. The motivation behind my research is to examine the planning diffusion process through urban consultancy, with the goal of bringing analytical and interpretative aspects of the ordinary process of urban consultancy into academic discourse. Combining the concepts of innovation and planning diffusion allows for an understanding of the local consequences of global urban consultancy. My research analyses the consequences of planning diffusion looking at institutional innovation processes in urban planning of Kigali which can be linked to the implementation of the Detailed Master Plan. The analysis is conducted in two strands. The first is an analysis of innovation resulting from identifying potential and relevant institutional innovations. My work develops an analytical scheme of potential and relevant institutional innovation in order to apply it in the case of urban planning in Kigali. The second strand is an analysis of planning diffusion, which should reveal the origins of potential institutional innovation and illustrate the conceptual term. My research also discusses negative effects of potential innovation and gives recommendations to create relevant institutional innovation.}, subject = {Urban planning; Urban management; Planning diffusion; Institutional innovation; Kigali (Rwanda); Stadtplanung; Stadtmanagement; Planungsdiffusion; Institutionelle Innovation; Kigali (Ruanda); Kigali; Stadtplanung; Strategisches Management; Innovation}, language = {en} } @phdthesis{Kronemann2014, author = {Kronemann, Jens}, title = {Untersuchung der zeitlichen Abh{\"a}ngigkeit von L{\"o}seprozessen in hochalkalischen L{\"o}sungen zur Charakterisierung der Alkaliempfindlichkeit von Gesteinsk{\"o}rnungen}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-35034}, school = {BTU Cottbus - Senftenberg}, year = {2014}, abstract = {Die sch{\"a}digende Alkali-Kiesels{\"a}ure-Reaktion (AKR) im Beton stellt in Teilbereichen nach wie vor ein Problem bei der Bewertung der Dauerhaftigkeit von Beton dar. Eine der h{\"a}ufigsten Fragestellungen ist immer noch eine schnelle und sichere Beurteilung der Alkaliempfindlichkeit von Gesteinsk{\"o}rnungen f{\"u}r die Betonherstellung. Dar{\"u}ber hinaus erscheint in Zeiten der Ressourceneinsparung der Ausschluss von Gesteinsk{\"o}rnungen auf Grund unzureichender Kenntnis der Alkaliempfindlichkeit nicht zukunftsorientiert. Weiterhin wird oft nur die makroskopische Betrachtung von Betonen oder M{\"o}rtelprismen zur Beurteilung der Alkaliempfindlichkeit von Gesteinsk{\"o}rnungen herangezogen, wobei die bei der AKR stattfindenden Prozesse nicht gen{\"u}gend ber{\"u}cksichtigt werden. In der vorliegenden Arbeit wurde der Beitrag von Gesteinsk{\"o}rnungen zur AKR im Beton untersucht, um die Alkaliempfindlichkeit von Gesteinsk{\"o}rnungen zu quantifizieren und die zu erwartende Sch{\"a}digung des Betons durch die Gesteinsk{\"o}rnung detaillierter als bisher klassifizieren zu k{\"o}nnen. Im Vordergrund der Arbeit stand dabei das Verst{\"a}ndnis der Aufl{\"o}sungsprozesse von Gesteinsk{\"o}rnungen in KOH-L{\"o}sungen (pH ≥ 13) bei unterschiedlichen Reaktionsbedingungen. An vier Gesteinsk{\"o}rnungen wurde der 40 °C-Betonversuch durchgef{\"u}hrt, um die Alkaliempfindlich-keit der Gesteinsk{\"o}rnungen zu dokumentieren. Weiter wurden die Gesteinsk{\"o}rnungen mit dem Schnellpr{\"u}fverfahren untersucht sowie petrografisch und mineralogisch begutachtet. Dabei stimm-ten die Ergebnisse nur teilweise mit denen des 40 °C-Betonversuchs {\"u}berein. Anhand von L{\"o}seversuchen an den originalen Lieferk{\"o}rnungen der Gesteinsk{\"o}rnungen bei 40 °C und mit 1,0 M KOH-L{\"o}sung war es m{\"o}glich, die Reaktivit{\"a}t der Gesteinsk{\"o}rnungen mit den ermittelten SiO₂- und Al₂O₃-Konzentrationen der alkalischen L{\"o}sungen zu beschreiben. Bei den Untersuchungen von verschiedenen Varianten zur Beschleunigung der L{\"o}seversuche konnten durch eine erh{\"o}hte Temperatur von 80 °C und eine abgesenkte Konzentration der KOH-L{\"o}sung von 0,1 M innerhalb von 56 Tagen vergleichbare Ergebnisse zu den Resultaten der L{\"o}seversuche bei 40 °C und 1,0 M KOH-L{\"o}sung erreicht werden. In der alkalischen L{\"o}sung wird ein bestimmter Teil des gel{\"o}sten SiO₂ durch ebenfalls vorhandenes Al₂O₃ alumosilikatisch gebunden. Der verbleibende Teil des gel{\"o}sten SiO₂ steht f{\"u}r eine AKR zur Verf{\"u}gung. Aus der zeitabh{\"a}ngigen Darstellung dieser SiO₂-Konzentration wurde die L{\"o}segeschwindigkeit ermittelt. Dabei wurden vier aufeinanderfolgende Phasen dem Dehnungs- und Rissbreitenverlauf der Probek{\"o}rper des 40 °C-Betonversuchs zugeordnet. Zur Beurteilung der Alkaliempfindlichkeit einer Gesteinsk{\"o}rnung sind die L{\"o}segeschwindigkeiten der letzten drei Phasen entscheidend. Nach der Entwicklung dieser Vorgehensweise an den vier untersuchten Gesteinsk{\"o}rnungen wurde diese Methode bei weiteren Gesteinsk{\"o}rnungen angewendet. Die ermittelten L{\"o}segeschwindigkeiten stellten ebenfalls ein exaktes Abbild der Ergebnisse des 40 °C-Betonversuchs dar. Die entwickelte Methode bietet eine M{\"o}glichkeit, die Alkaliempfindlichkeit einer Gesteinsk{\"o}rnung schnell, sicher und genauer als bisher zu bestimmen. Besonders vorteilhaft sind dabei die direkte Pr{\"u}fung der Gesteinsk{\"o}rnung an der originalen Korngr{\"o}ße (Lieferk{\"o}rnung), wie diese auch im Beton eingesetzt wird, die zementunabh{\"a}ngige Pr{\"u}fung, sowie die einfache experimentelle Durchf{\"u}hrung und Auswertung. Dar{\"u}ber hinaus zeigte sich bei der Anwendung der Methode, dass neben der Gesteinsk{\"o}rnung selbst auch der Einfluss von Zusatzstoffen auf die L{\"o}slichkeit von Gesteinsk{\"o}rnungen beurteilt werden kann. Erste Ergebnisse belegen den l{\"o}seinhibierenden Effekt des aluminiumhaltigen Zusatzstoffes Metakaolin durch die Blockierung der Oberfl{\"a}che einer reaktiven Gesteinsk{\"o}rnung im Alkalischen.}, subject = {Alkali-Kiesels{\"a}ure-Reaktion; Alkaliempfindlichkeit; L{\"o}slichkeit; L{\"o}segeschwindigkeit; Gesteinsk{\"o}rnung; Alkali-silica reaction; Alkali reactivity; Solubility; Dissolution rate; Aggregate; Zuschlagstoff ; L{\"o}slichkeit; Alkalische L{\"o}sung}, language = {de} } @phdthesis{Sahellie2015, author = {Sahellie, Samer}, title = {Study on the temperature effect on lap shear adhesive joints in lightweight steel construction}, issn = {1611-5023}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-35153}, school = {BTU Cottbus - Senftenberg}, year = {2015}, abstract = {In line with the developments in steel industry, the methods of joining steel members have been developed; therefore, the configuration of functional connections with economic and partly-aesthetic advantages has become possible by the use of the known joining methods, which are bolts, rivets and welding. However, these joining methods do not accompany the further developments and requirements needed to construct lightweight connections or to join dissimilar materials or composite constructions. Moreover, the traditional joining methods do not fulfill the increased requirements of the aesthetics of the joints. In the field of steel constructions, structural engineers might use the bonding technique as an alternative method to join the lightweight steel members or as a helpful mean in the bolted or riveted joints in heavyweight steel structures. Despite the advantages of the adhesive bonding technique, the structural designers in the field of steel constructions are still not able to use it in their practical applications because of the doubts regarding the verifiability of bonded steel joints. This is mainly because of the lack of standards for verifying such joints in steel constructions. To facilitate using this technique in steel constructions, hard efforts have to be performed in order to find out the methods of verifications of bonded steel joints. This starts with understanding the behaviour of the adhesive materials as well as their cohesion ability to the steel surfaces over the whole lifetime of the structure and under all possible loading and environmental conditions. Afterward, the mechanical properties of the adhesives have to be presented by their reliable values that take into account all factors and conditions to which the bonded joint is subjected. These values have to be based on the reliability methods and consequently they are guaranteed for the intended lifetime of the designed structure. It is well known that the adhesives, being viscoelastic materials, are very sensitive to several factors such as the environmental effects, mainly temperature and humidity, and the long-term loading. The loss of strength and durability of adhesives materials, due to the mentioned factors, is an essential aspect that has to be determined and to be taken into account of the structural designers during the design process. For example, it is generally proven that the increase of temperature causes a decrease in the elastic (E) and (G) moduli, cohesive and adhesive forces within the joint and maximum stresses which can be carried by the joint. However, there is still a huge lack in describing the degradations of the mechanical properties quantitatively. Similarly, the failure in the adhesives, loaded for long time by a constant stress even less than their short-term strengths, is probable due to the well-known rheological phenomenon of viscoelastic materials which is the creep phenomenon. Moreover, the adhesives will creep at high temperatures faster; hence the failure will happen in a shorter time. Describing the long-term behaviour of the structural adhesives is still modest; therefore, the time-to-failure of bonded steel joints under long-term loading cannot be exactly predicted. This is an essential issue has to be dealt with to fulfill the requirements of employing the adhesive bonding technique in the structural fields including the steel constructions. The efficiency of using adhesive-bonded joints in steel constructions is higher when the adhesives in these joints are loaded in shear. In such shear joints, the lightweight steel members (adherends) are likely to yield before the break within the adhesive layer happens, especially when large bonded areas are used because the developed shear stresses over the most of these areas will be very small. This thesis deals with the temperature influence on the behaviour of two adhesive systems (acrylic and epoxy) and on the capacities of adhesively bonded lap shear joints. The temperature influence is quantitatively described for short-term loading over a service range of temperature from -20 °C to +40 °C. The quantitative description is done by proposing the partial factors and the conversion factors that take the temperature effect into account. This influence is also dealt with for long-term loading to describe the shear creep behaviour of the adhesive materials used. Consequently, the time-to-failure of the bonded lap shear joints due to the creep phenomenon of the adhesives under three applied stresses at room temperature is predicted. Moreover, the estimation of time-to-failure is extended to be used for other shear stress levels. The temperature influence as well as the efficiency of using adhesive-bonded joints in lightweight galvanized steel constructions is also illustrated by giving a practical example of strengthening cold-formed "C" section girders. Comparisons between the two adhesive systems for all cases are given.}, subject = {Bonded steel joints; Temperature effect; Structural adhesives; Short and long-term loading; Shear strength; Geklebte Stahlverbindungen; Temperatureffekt; Strukturelle Klebstoffe; Kurz- und Langzeitverhalten; Schubspannung}, language = {en} } @phdthesis{Li2018, author = {Li, Zheng}, title = {Statistical size effect in steel structure and corresponding influence on structural reliability}, issn = {1611-5023}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-45557}, school = {BTU Cottbus - Senftenberg}, year = {2018}, abstract = {This thesis aims to investigate the statistical size effect in the elasto-plastic material and the corresponding reliability of steel structures. The core idea is that the stochastic material properties are directly embedded in mechanical calculations to develop a more accurate and economical design method for steel structure. Moreover, the results of the experimental investigation with different specimen sizes, whose diameter is limit up to 32 mm, show that the statistical size effect exists in steel structures. This thesis demonstrates finally that the structural reliability is affected by the statistical size effect and the structural safety can be optimized by considering this effect. Because of the uncertainty and non-uniformity of the microscopic imperfection distribution, the material strength in macroscale presents complex randomness. This study described the randomness of material properties through two different ways: developing a stochastic material model for elasto-plastic material and establishing a discrete random field with a general mathematical program. The proposed stochastic material model is extended to analyze the steel structure with multiaxial stress and is integrated into the commercial FEM software for analysis of the complex structures with stress gradient. The stochastic finite element method is implemented to analyze the response of the 3D structures by a general-purpose FEM program when the random field file is imported into the finite element model. The uniaxial tensile tests with different specimen sizes and different material are carried out to demonstrate the statistical size effect in steel structures. The results show that the variations of the yield and tensile strength increase with the decreasing specimen volume. Moreover, according to the bending tests, it is obvious that the structural component strength is not only related to the specimen volume, but also the stress distribution. These two proposed simulation methods, which are an extension and supplement to traditional simulation methods, can effectively simulate the statistical size effect for the tensile and flexural components in steel structures. Finally, it is found by studying the influence of statistical size effect on structural reliability that the strength, which is obtained by small specimens through statistical analysis in the laboratory, is no more accurately applicable to large construction. The reliability theory for the structural safety which exists over the decades can be compared and validated or improved through the embedding the stochastic material properties in the numerical simulation.}, subject = {Statistical size effect; Steel structure; Stochastic material model; Stochastic finite element method; Structural reliability; Statistischer Maßstabseffekt; Stahlbau; Stochastisches Materialmodell; Stochastische Finite-Elemente-Methode; Strukturelle Zuverl{\"a}ssigkeit; Stahlbau; Finite-Elemente-Methode; Stochastik; Stoffeigenschaft; Zuverl{\"a}ssigkeit}, language = {en} } @article{LuongZabelLorenzetal.2017, author = {Luong, Thi Mai Hoa and Zabel, Volkmar and Lorenz, Werner and Rohrmann, Rolf G.}, title = {Non-destructive Assessment of the Axial Stress State in Iron and Steel Truss Structures by Dynamic Measurements}, issn = {1877-7058}, doi = {10.1016/j.proeng.2017.09.447}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-42910}, year = {2017}, abstract = {This paper is concerned with the inverse identification of the stress state in axially loaded slender members of iron and steel truss structures using measured dynamic data. A methodology is proposed based on the finite element model updating coupled with nature-inspired optimization techniques, in particular the particle swarm optimization. The numerical model of truss structures is calibrated using natural frequencies and mode shapes from vibration tests, as well as additional information of the axial forces in selected truss members based on the experimentally identified modal parameters. The results of the identification are the axial forces or corresponding stresses in truss structures and the joint rigidity in relation to pinned and rigid conditions. Attention is given to several examined aspects, including the effects of the axial tensile and compressive forces on the dynamic responses of trusses, mode pairing criteria, as well as modeling assumptions of joints and the use of a joint rigidity parameter. Considering the pairing of modes, it is performed by adapting an enhanced modal assurance criterion that allows the selection of desired clusters of degrees-of-freedom. Thus, information extracted from the measurements related to specific modes is utilized in a more beneficial way. For modeling of joints, the numerical model of a truss structure includes rotational springs of variable stiffness to represent semi-rigid connections. Moreover, a fixity factor is introduced for practical estimation of the joint flexibility. The effectiveness of the proposed methodology is demonstrated by case studies involving simulated and laboratory experimental data.}, subject = {Lightweight truss structures; Stress state; Modal parameters; Finite element model updating; Nature-inspired optimization techniques; Eisenkonstruktion; Stahlkonstruktion; Tragwerk; Dynamische Belastung; Finite-Elemente-Methode}, language = {en} } @article{WeissLiedtkeStefan2025, author = {Weiss, Romano and Liedtke, Victoria and Stefan, R{\"o}diger}, title = {Cannabidiol does not cause DNA double-strand breaks in a human liver-derived cell model}, series = {Journal of Cannabis Research}, volume = {8}, journal = {Journal of Cannabis Research}, number = {12}, publisher = {BMC}, address = {London}, issn = {2522-5782}, doi = {10.1186/s42238-025-00365-w}, year = {2025}, abstract = {Cannabidiol (CBD) is a non-psychoactive cannabinoid with potential therapeutic applications, including anti-inflammatory, analgesic, and anticancer effects. However, experts raised concerns about its potential to induce DNA damage and chromosomal aberrations at low concentrations. Notably, these studies used liver cell lines, which may not fully reflect the metabolic processing of CBD, potentially limiting the generalizability of their findings. This study investigated the short time effects of CBD on DNA double-strand breaks (DSBs) and proliferation in the human liver-derived cell line HepG2. HepG2 cells were treated with CBD (5 - 50 μM, 3 - 72h incubation). To investigate potential imbalances in the expression of cannabinoid receptors 1 and 2 (CB1 / CB2) within HepG2 cells, we examined their expression using Western blot analysis. We hypothesized that such an imbalance could be associated with pathogenic processes. Double-strand breaks were then detected (5 μM Etoposide (ETP) served as positive control) via indirect immunofluorescence analysis using H2AX and 53BP1 antibodies, followed by quantification of DSB foci. Expression of CB2 but not CB1 was downregulated by 30 \% in HepG2 cells after exposure to 5 μM CBD (24h incubation; 0.05) and 70 \% downregulated after exposure to 50 μM CBD (24h incubation; 0.01). This effect was dose-dependent. Whilst ETP induced dose dependent DSBs, we could not confirm findings by others that CBD significantly increases the number of H2AX and 53BP1 foci between 5 μM and 50 μM (3h incubation; 0.05). In our model, CBD stimulated the cells, as confirmed by modulation of CB2 expression as well as changes in intracellular cAMP. Our results show that CBD in ranges between 5 μM to 50 μM does not significantly increase the amount of DNA double strand breaks in HepG2 cells compared to the control. However, we did observe a significant reduction in cell proliferation and a significant increase in intracellular cAMP levels following CBD treatment.}, subject = {Cannabidiol; DNA damage; Proliferation; CAMP; HepG2}, language = {en} } @article{OttoPuchol‑RoyoOrtega‑Legarretaetal.2024, author = {Otto, Pascal and Puchol‑Royo, Roser and Ortega‑Legarreta, Asier and Tanner, Kristie and Tideman, Jeroen and Vries, Sjoerd‑Jan de and Pascual, Javier and Porcar, Manuel and Latorre‑P{\´e}rez, Adriel and Abendroth, Christian}, title = {Multivariate comparison of taxonomic, chemical and operational data from 80 different full‑scale anaerobic digester‑related systems}, series = {Biotechnology for Biofuels and Bioproducts}, volume = {17}, journal = {Biotechnology for Biofuels and Bioproducts}, publisher = {BMC}, address = {London}, issn = {2731-3654}, doi = {10.1186/s13068-024-02525-1}, year = {2024}, abstract = {The holistic characterization of different microbiomes in anaerobic digestion (AD) systems can contribute to a better understanding of these systems and provide starting points for bioengineering. The present study investigates the microbiome of 80 European full-scale AD systems. Operational, chemical and taxonomic data were thoroughly collected, analysed and correlated to identify the main drivers of AD processes. The present study describes chemical and operational parameters for a broad spectrum of different AD systems. With this data, Spearman correlation and differential abundance analyses were applied to narrow down the role of the individual microorganisms detected. The authors succeeded in further limiting the number of microorganisms in the core microbiome for a broad range of AD systems. Based on 16S rRNA gene amplicon sequencing, MBA03, Proteiniphilum, a member of the family Dethiobacteraceae, the genus Caldicoprobacter and the methanogen Methanosarcina were the most prevalent and abundant organisms identified in all digesters analysed. High ratios for Methanoculleus are often described for agricultural co-digesters. Therefore, it is remarkable that Methanosarcina was surprisingly high in several digesters reaching ratios up to 47.2\%. The various statistical analyses revealed that the microorganisms grouped according to different patterns. A purely taxonomic correlation enabled a distinction between an acetoclastic cluster and a hydrogenotrophic one. However, in the multivariate analysis with chemical parameters, the mainclusters corresponded to hydrolytic and acidogenic microorganisms, with SAOB bacteria being particularly important in the second group. Including operational parameters resulted in digester-type specific grouping of microbes. Those with separate acidification stood out among the many reactor types due to their unexpected behaviour. Despite maximizing the organic loading rate in the hydrolytic pretreatments, these stages turned into extremely robust methane production units. From 80 different AD systems, one of the most holistic data sets is provided. A very distinct formation of microbial clusters was discovered, depending on whether taxonomic, chemical or operational parameters were combined. The microorganisms in the individual clusters were strongly dependent on the respective reference parameters.}, subject = {Anaerobic digestion; 16S rRNA sequencing; Core microbiome; Multivariate analysis; Parameter dependency; G{\"a}rung; Mikrobiom ; Multivariate Analyse; Laborparameter}, language = {en} } @article{KimGerstbergerAslietal.2025, author = {Kim, Dongsuk and Gerstberger, Ulf and Asli, Majid and H{\"o}schler, Klaus}, title = {U-Net Driven Semantic Segmentation for Detection and Quantification of Cracks on Gas Turbine Blade Tips}, series = {Results in Engineering}, volume = {29}, journal = {Results in Engineering}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2590-1230}, doi = {10.1016/j.rineng.2025.108864}, year = {2025}, abstract = {Crack detection and quantification on gas turbine blades is crucial for component validation during the development phase and for operational efficiency in service, as unexpected cracks can compromise blade integrity and lead to early engine removals. Gas turbine blades operate under extreme thermal and mechanical stresses, making them particularly susceptible to crack formation. At the same time deterministic predictions of crack formation are subject to high uncertainty in material data and actual loading conditions. Accurate detection and quantification of cracks, therefore, is essential for the validation and calibration of life predictions in order to prevent in-service failures, to extend component lifespan, and to reduce maintenance costs. This study introduces a U-Net based semantic segmentation model designed to automate crack detection on turbine blade tips. The model was trained on a dataset of 210 surface images with and without evidence of cracks, each divided into 128  ×  128 pixel patches. Data augmentation techniques were applied to address the class imbalance between cracked and non-cracked pixels. The U-Net architecture, optimized with a Dice loss function, achieved a validation IoU of 0.7557, along with approximately 85\% recall and precision in identifying cracked pixels. The pixel-based accuracy of the model primarily affects the quantification of cracks rather than their identification. A sliding window pipeline was implemented to extend the model's applicability, enabling segmentation of entire blade tip images for comprehensive crack localization. While the model may occasionally miss low-contrast cracks, it holds potential as a supplementary tool for manual inspection as part of the life prediction validation. By providing automated crack localization and quantification, the model can assist in analyzing crack characteristics relative to engine operating conditions.}, subject = {Crack detection; Semantic segmentation; Gas turbine blade; U-Net; Deep learning; Convolutional neural network}, language = {en} } @article{OleynikRyzhakSchlipfetal.2025, author = {Oleynik, Paul and Ryzhak, Diana and Schlipf, Jon and Alvarado Chavarin, Carlos and Yamamoto, Yuji and Berkmann, Fritz and Ratzke, Markus and Fischer, Inga Anita}, title = {Influence of illumination conditions on photoluminescence enhancement in an Al/Si/Ge metasurface}, series = {Optics Express}, volume = {34}, journal = {Optics Express}, number = {1}, publisher = {Optica Publishing Group}, address = {Washington D.C.}, issn = {1094-4087}, doi = {10.1364/OE.577751}, pages = {78 -- 86}, year = {2025}, abstract = {Strong field enhancement supported by metasurfaces at resonance can be used to control and enhance the spontaneous emission rate of emitters. This is particularly relevant for emitters with comparatively low quantum yield such as germanium. Here, we investigate the µ-photoluminescence response obtained from a hybrid metasurface comprising a square lattice of Al/Si/Ge pillars. We explore how variations in excitation energy, excitation intensity and number of excited meta-atoms affect the spectral dependence of the photoluminescence signal and, in particular, the contribution of the metasurface to it. Our metasurface exhibits a magnetic dipole collective lattice resonance, whose contribution to the photoluminescence signal increases with increasing number of excited meta-atoms. Measuring only one metasurface under different illumination conditions can potentially be an alternative approach to probe the transition between finite-size effects and collective effects.}, subject = {Field enhancement; Germanium; Light emitting diodes; Photonic crystals; Quantum light sources; Scanning electron microscop}, language = {en} }