TY - JOUR A1 - Liedtke, Victoria A1 - Wartmann, Thomas A1 - Shi, Wenjie A1 - Kahlert, Ulf D. T1 - Linking LEDGF/p75 overexpression with microsatellite instability and KRAS mutations : a small-scale study in colorectal cancer JF - Cancer Control N2 - Colorectal cancer (CRC) ranks third in men and second in women, with 153,020 new cases and 52,550 deaths in 2023, and with a projected incidence of 2.2 million new cases by 2030 due to lifestyle changes and enhanced diagnostic capabilities. Identification and analysis of new biomarkers, like lens epithelium-derived growth factor splice variant of 75 kDa (LEDGF/p75), which is known to play a crucial role as stress-related oncogene, can make a significant contribution in facilitating early CRC detection. This study analyzed the expression of LEDGF/p75 and the ubiquitin E2 conjugating enzyme UBC13 in 15 CRC tissue samples and adjacent non-tumor tissues. All patient samples underwent NGS-based mutation analysis beforehand. The western blot technique was used for protein analysis, and the results were further validated using mRNA expression data from 521 patient samples from the TCGA database. LEDGF/p75 expression was significantly elevated in nearly all tumor tissue samples compared to adjacent tissue (11/15, 73.3%). Additionally, the UBC13 enzyme, a key regulator in the degradation of signaling molecules, was also increased in most tumor tissue samples (9/15, 60.0%). Co-overexpression of LEDGF/p75 and UBC13 was evident in 6/6 patients. Patients with KRAS and MSH2 mutations showed a 75% and 100% correlation with LEDGF/p75 overexpression, respectively. This study confirms the upregulation of LEDGF/p75 in CRC and shows its correlation with KRAS and MSH2 mutations. The interaction of LEDGF/p75 with DNA damage response proteins may contribute to drug resistance and increased tumor aggressiveness. LEDGF/p75’s potential as a prognostic biomarker independent of lymph node involvement or CEA levels highlights its potential in personalized therapy, and warrants further research into its therapeutic targeting. KW - LEDGF/p75 KW - Colorectal cancer KW - Biomarker KW - Personalized therapy KW - DNA repair Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:co1-opus4-69673 VL - 32 SP - 1 EP - 9 PB - Sage CY - London ER - TY - BOOK A1 - Künnemann, Andreas T1 - Existenz- und Regularitätstheorie der zweidimensionalen Variationsrechnung mit Anwendungen auf das Plateausche Problem für Flächen vorgeschriebener mittlerer Krümmung T1 - Existence and regularity theory of the two-dimensional calculus of variations with applications to the plateau problem for surfaces of prescribed mean curvature N2 - Die vorliegende Arbeit behandelt für eine breite Klasse zweidimensionaler Variationsprobleme eine Existenz- und Regularitätstheorie, die der Lösung von Randwertproblemen partieller Differentialgleichungssysteme dient. Dabei werden bekannte Ergebnisse gründlich untersucht und umfassend aufgearbeitet. Teilweise wird eine geeignete Anpassung der Voraussetzungen einiger Resultate vorgenommen. Speziell wird die Theorie auf das Plateausche Problem für Flächen vorgeschriebener mittlerer Krümmung im R3 angewendet. Eingangs wird das Konzept der direkten Methoden der Variationsrechnung erläutert. Über einen fundamentalen Satz zur schwachen Unterhalbstetigkeit von Funktionalen wird die Existenz eines Minimierers für eine breite Klasse von Variationsproblemen nachgewiesen. Da die Existenztheorie in Sobolev-Räumen agiert, sind Untersuchungen zur Regularität eines Minimierers notwendig. Im Rahmen der Regularitätstheorie wird das Dirichletsche Wachstumstheorem von Morrey gezeigt, welches ein hinreichendes Kriterium für die Hölder-Stetigkeit einer Funktion X ∈ W1,2(G) liefert. Zum Nachweis der Anwendbarkeit des Dirichletschen Wachstumstheorems auf einen Minimierer wird ein Wachstumslemma verwendet. Dabei werden eine Verknüpfung des Dirichlet-Integrals mit Fourierreihen sowie das Dirichlet- Integral der harmonischen Ersetzung einer Funktion mit L2-Randwerten genutzt. Infolgedessen ergibt sich die Hölder-Stetigkeit im Inneren für einen Minimierer. Zudem wird die Stetigkeit des Minimierers bis zum Rand gezeigt, sodass die Existenz eines stetigen Minimierers für eine breite Klasse von Variationsproblemen gesichert ist. Anschließend erfolgt die Berechnung der ersten Variation sowie die damit verbundene Herleitung der schwachen Euler-Lagrange-Gleichung, welche eine Beziehung zur Lösungstheorie von Differentialgleichungen im Sinne des Dirichletschen Prinzips herstellt. Ausgehend von der schwachen Euler-Lagrange-Gleichung wird die Hölder-Stetigkeit der ersten Ableitungen eines Minimierers bewiesen. Für die Lösung von Randwertproblemen mit partiellen Differentialgleichungen zweiter Ordnung mithilfe der Variationsrechnung ist der Nachweis stetiger zweiter Ableitungen des Minimierers notwendig. Dabei wird der Fokus auf sogenannte Minimierer vom Poissonschen Typ gelegt. Eine C2,σ-Rekonstruktion, die auf der Schaudertheorie basiert, liefert in diesem Fall die gewünschte Regularität. In Anwendung dessen werden das Randwertproblem harmonischer Abbildungen in Riemannschen Räumen sowie das Dirichletproblem des H-Flächen-Systems behandelt, indem jeweils ein geeignetes Variationsproblem aufgestellt wird. Als Erweiterung des Dirichletproblems des H-Flächen-Systems wird das allgemeine Plateausche Problem für Flächen vorgeschriebener mittlerer Krümmung mit den erarbeiteten Methoden der Variationsrechnung untersucht. Zudem wird das Plateausche Problem für Flächen vorgeschriebener mittlerer Krümmung in Kugeln, in Zylindern sowie insbesondere im Einheitskegel gelöst. Insgesamt wird eine ausführliche, in sich geschlossene und gut verständliche Existenzund Regularitätstheorie der zweidimensionalen Variationsrechnung zur Behandlung von Randwertproblemen partieller Differentialgleichungssysteme dargestellt, welche sich in besonderer Weise bei der Lösung des Plateauschen Problems für Flächen vorgeschriebener mittlerer Krümmung entfaltet. N2 - This work deals with the existence and regularity theory for a wide class of twodimensional variational problems, with the intention to solve boundary value problems for systems of partial differential equations. Known results are thoroughly examined and comprehensively elaborated. Partially, the requirements for some of the results are suitably adapted. In particular, the theory is applied to Plateau’s problem for surfaces of prescribed mean curvature in R3. At the beginning, the concept of the direct methods in the calculus of variations is explained. The existence of a minimizer for a wide class of variational problems is demonstrated by means of a fundamental theorem on the weak lower semicontinuity of functionals. Since the existence theory operates in Sobolev spaces, investigations about the regularity of a minimizer are necessary. In the context of the regularity theory, the Dirichlet growth theorem by Morrey is shown, which provides a sufficient condition for the Hölder continuity of a function X ∈ W1,2(G). A growth lemma is used to demonstrate the applicability of the Dirichlet growth theorem to a minimizer. A combination of the Dirichlet integral with Fourier series and the Dirichlet integral for the harmonic replacement of a function with L2 boundary values are utilized. As a result, the Hölder continuity in the interior for a minimizer is established. In addition, the continuity of the minimizer up to the boundary is shown, so that the existence of a continuous minimizer is ascertained for a wide class of variational problems. Subsequently, the first variation is calculated and the associate weak Euler-Lagrange equation, which relates to solutions of differential equations in the sense of Dirichlet’s principle, is derived. The weak Euler-Lagrange equation is the base for proving the Hölder continuity of the first derivatives for a minimizer. In order to solve boundary value problems with partial differential equations of the second order via the calculus of variations, the proof of continuous second derivatives for the minimizer is necessary. The focus is laid on so-called minimizers of Poisson type. A C2,σ-reconstruction based on the Schauder theory provides the desired regularity in this case. As an application of this theory, the boundary value problem of harmonic mappings in Riemannian spaces as well as the Dirichlet problem of the H-surface system are treated via the solution of a suitable variational problem in each case. As an extension for the Dirichlet problem of the H-surface system, the general Plateau’s problem for surfaces of prescribed mean curvature is investigated using the variational methods that have been developed. In addition, Plateau’s problem for surfaces of prescribed mean curvature is solved in balls, in cylinders and especially in the unit cone. With these investigations a detailed, self-contained and easily understandable existence and regularity theory of the two-dimensional calculus of variations for the treatment of boundary value problems for systems of partial differential equations is presented, which is especially suited to solve Plateau’s problem for surfaces with prescribed mean curvature. KW - Variationsrechnung KW - Variationsrechnung KW - Dimension 2 KW - Mittlere Krümmung KW - Plateau-Problem KW - Partielle Differentialgleichungen KW - Plateausches Problem KW - Regularitätstheorie KW - Morrey KW - Variation calculation KW - Partial differential equations KW - Plateau problem KW - Regularity theory Y1 - 2022 SN - 978-3-658-41640-9 U6 - https://doi.org/10.1007/978-3-658-41641-6 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Richter, Jana A1 - Rachow, Fabian A1 - Israel, Johannes A1 - Roth, Norbert A1 - Charlafti, Evgenia A1 - Günther, Vivien A1 - Flege, Jan Ingo A1 - Mauss, Fabian T1 - Reaction mechanism development for methane steam reforming on a Ni/Al2O3 catalyst T1 - Entwicklung eines Reaktionsmechanismus für die Methan-Dampfreformierung an einem Ni/Al2O3-Katalysator N2 - In this work, a reliable kinetic reaction mechanism was revised to accurately reproduce the detailed reaction paths of steam reforming of methane over a Ni/Al2O3 catalyst. A steadystate fixed-bed reactor experiment and a 1D reactor catalyst model were utilized for this task. The distinctive feature of this experiment is the possibility to measure the axially resolved temperature profile of the catalyst bed, which makes the reaction kinetics inside the reactor visible. This allows for understanding the actual influence of the reaction kinetics on the system; while pure gas concentration measurements at the catalytic reactor outlet show near-equilibrium conditions, the inhere presented temperature profile shows that it is insufficient to base a reaction mechanism development on close equilibrium data. The new experimental data allow for achieving much higher quality in the modeling efforts. Additionally, by carefully controlling the available active surface via dilution in the experiment, it was possible to slow down the catalyst conversion rate, which helped during the adjustment of the reaction kinetics. To assess the accuracy of the revised mechanism, a monolith experiment from the literature was simulated. The results show that the fitted reaction mechanism was able to accurately predict the experimental outcomes for various inlet mass flows, temperatures, and steam-to-carbon ratios. N2 - In dieser Arbeit wurde ein zuverlässiger kinetischer Reaktionsmechanismus überarbeitet, um die detaillierten Reaktionswege der Dampfreformierung von Methan über einem Ni/Al2O3-Katalysator genau zu reproduzieren. Dazu wurden ein stationäres Festbettreaktorexperiment und ein 1D-Reaktor Katalysatormodell verwendet. Die Besonderheit dieses Experiments ist die Möglichkeit das axial aufgelöste Temperaturprofil des Katalysatorbetts zu messen, wodurch die Reaktionskinetik im Reaktor sichtbar wird. Dies ermöglicht es den tatsächlichen Einfluss der Reaktionskinetik auf das System zu verstehen. Während Messungen der reinen Gaskonzentration am Ausgang des katalytischen Reaktors Bedingungen nahe am Gleichgewicht zeigen, zeigt das hier dargestellte Temperaturprofil, dass es nicht ausreicht, die Entwicklung eines Reaktionsmechanismus auf Daten nahe am Gleichgewicht zu stützen. Die neuen experimentellen Daten ermöglichen es, eine wesentlich höhere Qualität bei der Modellierung zu erreichen. Durch eine sorgfältige Kontrolle der verfügbaren aktiven Oberfläche mittels Verdünnung im Experiment war es außerdem möglich, die Katalysatorumsatzrate zu verlangsamen, was bei der Anpassung der Reaktionskinetik hilfreich war. Um die Genauigkeit des überarbeiteten Mechanismus zu bewerten, wurde auch ein Monolith-Experiment aus der Literatur simuliert. Die Ergebnisse zeigen, dass der angepasste Reaktionsmechanismus in der Lage war, die experimentellen Ergebnisse für verschiedene Einlassmassenströme, Temperaturen und Dampf-Kohlenstoff-Verhältnisse genau vorherzusagen. KW - 1D modeling KW - Reaction rates KW - Methane steam reforming KW - Fixed-bed reactor experiments KW - Nickel catalyst KW - 1D-Modellierung KW - Reaktionsgeschwindigkeiten KW - Methan-Dampfreformierung KW - Festbettreaktor-Experimente KW - Nickel-Katalysator KW - Katalysator KW - Reaktionsmechanismus KW - Festbettreaktor KW - Steamreforming KW - Reaktionsgeschwindigkeit Y1 - 2023 U6 - https://doi.org/10.3390/catal13050884 ER - TY - JOUR A1 - Asli, Majid A1 - Mhgoub, Mosaab A1 - Klaus, Höschler T1 - Numerical investigation of a turbine working with a highly unsteady exhaust flow of a hydrogen-driven rotating detonation combustion JF - International Journal of Thermofluids N2 - Traditionally, turbomachines are designed for steady-state operations around which they achieve optimal performance and efficiency. However, in novel applications, a turbomachine may be exposed to unsteady flow forcing the machine to operate under fluctuating off design conditions. Pressure Gain Combustion (PGC) through detonation can be an extreme example of unsteady flow which affects the turbine performance adversely. The efficient way of energy extraction from PGCs is still an open question which needs extensive turbine design optimizations for such unsteady flow. Any flow field optimization problem in such applications needs a multitude of simulations, which can be too computationally expensive to be utilized as it is realized as an unsteady 3D-CFD problem. In this regard, the current study aims at proposing and evaluating an approach for optimizing a turbine working under highly unsteady exhaust flow of a Rotating Detonation Combustion (RDC). A two stage turbine is placed downstream an RDC and the turbine inlet condition is calculated by a 2D-Euler simulation tool. A turbine optimization problem is defined and three optimization processes with an objective of minimizing entropy are performed using steady-state 3D-CFD simulation as the objective function evaluator. The turbine inlet boundary conditions in the three optimization efforts include peak, mean and trough values of the RDC outlet pulsating flow condition. Finally, detailed unsteady simulations are carried out for the three new geometries and compared with the baseline turbine. The results showed that the steady-state Reynolds Averaged Navier Stocks (RANS) simulations can be utilized using either mean or trough values of the pulsating boundary condition in iterating a design optimization problem, instead of full unsteady RANS simulations applying time and circumferential location dependent boundary conditions. Given the specific RDC boundary condition and the turbine geometry in this study, the optimized turbine exhibited up to 7.71% less entropy generation and up to 7% higher output power compared to the baseline counterpart in unsteady operation. This approach enables a more efficient design optimization process while accounting for the complex dynamics of the RDC exhaust flow. Overall, the approach presented in this paper is practical for optimizing highly unsteady turbomachines specifically for the case of RDCs during any early design optimization procedure, addressing the computational challenges associated with simulating unsteady flows while ensuring the turbine’s effectiveness under real operating conditions. KW - Unsteady turbine KW - Entropy generation KW - Rotating detonation KW - Optimization KW - Computational fluid dynamic Y1 - 2025 U6 - https://doi.org/10.1016/j.ijft.2025.101356 SN - 2666-2027 VL - 29 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Ertugrul, Gökhan A1 - Emdadi, Aliakbar A1 - Härtel, Sebastian T1 - Powder production and additive manufacturing of iron aluminide alloys using plasma ultrasonic atomization and laser-directed energy deposition JF - Additive Manufacturing Letters N2 - With a combination of desirable properties such as low density, high specific yield strength, low material cost, and excellent oxidation and corrosion resistance, iron aluminide (Fe-Al) has shown considerable potential to be an alternative to high-alloy chromium steels, and in some cases even nickel-based superalloys, in hightemperature applications. Due to these features, it is especially suitable for the aerospace and automotive industries. Recent advancements indicate an increasing interest in Fe-Al within the additive manufacturing industry, particularly in directed energy deposition (DED) processes. Despite this progress, processing of Fe-Al materials using the laser directed energy deposition (L-DED) has not been sufficiently investigated. In this study, Fe-Al powder material was produced from a commercial Al rod encased in a commercial low alloy-steel tube by a plasma-based ultrasonic atomization eliminating the need to cast an alloy ingot in advance. Subsequently, the produced powder was used in a L-DED process to fabricate an additively manufactured sample. The sample was investigated in terms of mechanical property, microstructure, chemical composition, and phase structure by scanning electron microscope (SEM) / energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), electron backscatter diffraction (EBSD) and microhardness analyses. KW - Iron aluminides (Fe-Al) KW - Laser directed energy deposition (L-DED) KW - Plasma ultrasonic atomization KW - Powder KW - Intermetallic phase Y1 - 2025 U6 - https://doi.org/10.1016/j.addlet.2025.100313 SN - 2772-3690 VL - 14 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Rim, Imen A1 - Hezil, Naouel A1 - Fellah, Mamoun A1 - Saoudi, Adel A1 - Aleksei, Obrosov A1 - El-Hiti, Gamal A. T1 - Enhancing kaolin performance through organic molecule modification and assessing its efficiency for lead and copper adsorption JF - Environmental Technology & Innovation N2 - The research aimed to enhance the efficacy of kaolin in water treatment by incorporating diphenylamine (DPA) and to evaluate its effectiveness in adsorbing lead and copper in wastewater in comparison to natural kaolin (Nat-kaolin). This entailed modifying kaolin with DPA to create DPA-kaolin and conducting comprehensive characterization utilizing a range of techniques, including X-ray diffraction analysis (XRD), scanning electron microscope (SEM), energy dispersion X-ray (EDX), thermogravimetric analysis (TGA), differential thermal analysis (DTA), Fourier-transform infrared spectroscopy (FTIR), and Brunauer-Emmett-Teller (BET) analysis. The results demonstrated the successful modification of DPA, as evidenced by an increase in BET-specific surface area of about 25 % (from 66.69 m².g⁻¹ to 71.35 m².g⁻¹), indicating enhanced adsorption capacity. XRD analysis confirmed the composition of the samples, while TGA/DTA indicated changes in water adsorption and dehydroxylation. SEM and EDX illustrated the tubular nature of the clay with a decrease in the amount of Al, about 10.76 %, and the amount of Si, about 10.38 %, on the DPA-kaolin. Notably, the FTIR spectrum of DPA-kaolin showed the presence of new vibration bands at 1248 cm⁻¹, indicating the presence of DPA. In terms of adsorption, the DPA-kaolin exhibited significantly higher maximum adsorption capacities for Pb(II) and Cu(II) compared to the nat-kaolin, with values of 151 μmol/g and 134 μmol/g, respectively.These values were significantly higher than those observed for Nat-kaolin, which demonstrated adsorption capacities of 103 μmol/g for Pb(II) and 91 μmol/g for Cu(II). The adsorption kinetics indicated that the pseudo-second-order kinetic model described the sorption mechanism for both Pb(II) and Cu(II). This was evidenced by the values of R², which were 0.999 and 0.996, respectively. The study provides clear evidence that DPA-kaolin is more effective than Nat-kaolin in removing lead (Pb(II)) and copper (Cu(II)) from wastewater. Through rigorous experimentation, it was observed that DPA-kaolin exhibited notably enhanced adsorption capabilities for both Pb(II) and Cu(II) compared to Nat-kaolin. These findings serve to emphasize the practical importance and potential. KW - Kaolin clay KW - Water treatment KW - DPA-Kaolin KW - Chemical treatment KW - Adsorption KW - Isotherms Y1 - 2025 U6 - https://doi.org/10.1016/j.eti.2024.103904 SN - 2352-1864 VL - 36 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Franken, Tim A1 - Netzer, Corinna A1 - Mauss, Fabian A1 - Pasternak, Michal A1 - Seidel, Lars A1 - Borg, Anders A1 - Lehtiniemi, Harry A1 - Matrisciano, Andrea A1 - Kulzer, Andre Casal T1 - Multi-objective optimization of water injection in spark-ignition engines using the stochastic reactor model with tabulated chemistry N2 - Water injection is investigated for turbocharged spark-ignition engines to reduce knock probability and enable higher engine efficiency. The novel approach of this work is the development of a simulation-based optimization process combining the advantages of detailed chemistry, the stochastic reactor model and genetic optimization to assess water injection. The fast running quasi-dimensional stochastic reactor model with tabulated chemistry accounts for water effects on laminar flame speed and combustion chemistry. The stochastic reactor model is coupled with the Non-dominated Sorting Genetic Algorithm to find an optimum set of operating conditions for high engine efficiency. Subsequently, the feasibility of the simulation-based optimization process is tested for a three-dimensional computational fluid dynamic numerical test case. The newly proposed optimization method predicts a trade-off between fuel efficiency and low knock probability, which highlights the present target conflict for spark-ignition engine development. Overall, the optimization shows that water injection is beneficial to decrease fuel consumption and knock probability at the same time. The application of the fast running quasi-dimensional stochastic reactor model allows to run large optimization problems with low computational costs. The incorporation with the Non-dominated Sorting Genetic Algorithm shows a well-performing multi-objective optimization and an optimized set of engine operating parameters with water injection and high compression ratio is found. KW - Ottomotor KW - Water injection KW - Genetic optimization KW - Spark-ignition engine KW - Stochastic reactor model KW - Detailed chemistry KW - Wassereinspritzung KW - Prozessoptimierung KW - Stochastisches Modell Y1 - 2019 U6 - https://doi.org/10.1177/1468087419857602 SN - 1468-0874 SN - 2041-3149 PB - SAGE Publications CY - London, England ER - TY - JOUR A1 - Ali, Aamir A1 - Khan, Muhammad Moman A1 - Kolenda, Rafal A1 - Olowe, Olugbenga Adekunie A1 - Weinreich, Jörg A1 - Li, Ganwu A1 - Schierack, Peter T1 - The role of AJB35136 and fdtA genes in biofilm formation by avian pathogenic Escherichia coli T1 - Die Rolle von AJB35136- und fdtA-Genen bei der Biofilmbildung von aviären pathogenen Escherichia coli N2 - Background Infections caused by avian pathogenic Escherichia coli (APEC) result in significant economic losses in poultry industry. APEC strains are known to form biofilms in various conditions allowing them to thrive even under harsh and nutrient-deficient conditions on different surfaces, and this ability enables them to evade chemical and biological eradication methods. Despite knowing the whole genome sequences of various APEC isolates, little has been reported regarding their biofilm-associated genes. A random transposon mutant library of the wild-type APEC IMT 5155 comprising 1,300 mutants was analyzed for biofilm formation under nutrient deprived conditions using Videoscan technology coupled with fluorescence microscopy. Seven transposon mutants were found to have reproducibly and significantly altered biofilm formation and their mutated genes were identified by arbitrary PCR and DNA sequencing. The intact genes were acquired from the wild-type strain, cloned in pACYC177 plasmid and transformed into the respective altered biofilm forming transposon mutants, and the biofilm formation was checked in comparison to the wild type and mutant strains under the same conditions. Results In this study, we report seven genes i.e., nhaA, fdeC, yjhB, lysU, ecpR, AJB35136 and fdtA of APEC with significant contribution to biofilm formation. Reintroduction of AJB35136 and fdtA, reversed the altered phenotype proving that a significant role being played by these two O-antigen related genes in APEC biofilm formation. Presence of these seven genes across nonpathogenic E. coli and APEC genomes was also analyzed showing that they are more prevalent in the latter. N2 - Hintergrund Infektionen, die durch aviäre pathogene Escherichia coli (APEC) verursacht werden, führen zu erheblichen wirtschaftlichen Verlusten in der Geflügelindustrie. Es ist bekannt, dass APEC-Stämme unter verschiedenen Bedingungen Biofilme bilden, die es ihnen ermöglichen, selbst unter rauen und nährstoffarmen Bedingungen auf verschiedenen Oberflächen zu gedeihen. Diese Fähigkeit ermöglicht es ihnen, sich chemischen und biologischen Eradikationsmethoden zu entziehen. Obwohl die gesamten Genomsequenzen verschiedener APEC-Isolate bekannt sind, wurde bisher nur wenig über ihre Biofilm-assoziierten Gene berichtet. Eine zufällige Transposon-Mutantenbibliothek des Wildtyps APEC IMT 5155, die 1.300 Mutanten umfasst, wurde mit Hilfe der Videoscan-Technologie in Verbindung mit Fluoreszenzmikroskopie auf Biofilmbildung unter nährstoffarmen Bedingungen untersucht. Bei sieben Transposon-Mutanten wurde eine reproduzierbare und signifikant veränderte Biofilmbildung festgestellt, und ihre mutierten Gene wurden durch willkürliche PCR und DNA-Sequenzierung identifiziert. Die intakten Gene wurden dem Wildtyp-Stamm entnommen, in das pACYC177-Plasmid kloniert und in die jeweiligen veränderten biofilmbildenden Transposon-Mutanten transformiert, und die Biofilmbildung wurde im Vergleich zum Wildtyp und den mutierten Stämmen unter denselben Bedingungen überprüft. Ergebnisse In dieser Studie konnten wir sieben Gene, d.h. nhaA, fdeC, yjhB, lysU, ecpR, AJB35136 und fdtA von APEC mit einem signifikanten Beitrag zur Biofilmbildung nachweisen. Die Wiedereinführung von AJB35136 und fdtA kehrte den veränderten Phänotyp um, was beweist, dass diese beiden mit dem O-Antigen verbundenen Gene eine wichtige Rolle spielen. KW - APEC KW - Biofilm KW - Gene KW - Complementation KW - Transposon mutant KW - VideoScan KW - Genkomplementierung KW - Transposon-Mutanten KW - Geflügelkrankheit KW - Escherichia coli KW - Biofilm KW - Komplementation KW - Transponson KW - Mutant Y1 - 2023 U6 - https://doi.org/10.1186/s12917-023-03672-7 ER - TY - JOUR A1 - Rakhi, A1 - Mauss, Fabian T1 - Numerical investigation of equilibrium and kinetic aspects for hydrogenation of CO₂ JF - Catalysts N2 - Even if huge efforts are made to push alternative mobility concepts, such as electric cars and fuel-cell-powered cars, the significance and use of liquid fuels is anticipated to stay high during the 2030s. Biomethane and synthetic natural gas (SNG) might play a major role in this context, as they are raw material for chemical industry that is easy to be stored and distribute via existing infrastructure, and are a versatile energy carrier for power generation and mobile applications. Since biomethane and synthetic natural gas are suitable for power generation and for mobile applications, they can therefore replace natural gas without any infrastructure changes, thus playing a major role. In this paper, we aim to comprehend the direct production of synthetic natural gas from CO₂ and H₂ in a Sabatier process based on a thermodynamic analysis as well as a multi-step kinetic approach. For this purpose, we thoroughly discuss CO₂ methanation to control emissions in order to maximize the methane formation along with minimizing the CO formation and to understand the complex methanation process. We consider an equilibrium and kinetic modeling study on the NiO-SiO₂catalyst for methanation focusing on CO₂-derived SNG. The thermodynamic analysis of CO₂ hydrogenation is preformed to define the optimal process parameters followed by the kinetic simulations for catalyst development. The investigation presented in this paper can also be used for developing machine learning algorithms for methanation processes. KW - Equilibrium calculations KW - Thermodynamic analysis KW - Kinetic modeling KW - CO₂ Methanation KW - Gibbs free energy minimization Y1 - 2024 U6 - https://doi.org/10.3390/catal14090562 SN - 2073-4344 VL - 14 IS - 9 PB - MDPI CY - Basel ER - TY - JOUR A1 - Shafiee, Parisa A1 - Dorneanu, Bogdan A1 - Arellano-Garcia, Harvey T1 - Improving catalysts and operating conditions using machine learning in Fischer-Tropsch synthesis of jet fuels (C8-C16) JF - Chemical Engineering Journal Advances N2 - Fischer-Tropsch synthesis (FTS) offers a promising route for producing sustainable jet fuels from syngas. However, optimizing catalyst design and operating conditions for the ideal C8-C16 jet fuel range is challenging. Thus, this work introduces a machine learning (ML) framework to enhance Co/Fe-supported FTS catalysts and optimize their operating conditions for a better jet fuel selectivity. For this purpose, a dataset was implemented with 21 features, including catalyst structure, preparation method, activation procedure, and FTS operating parameters. Moreover, various machine-learning models (Random Forest (RF), Gradient Boosted, CatBoost, and artificial neural networks (ANN)) were evaluated to predict CO conversion and C8-C16 selectivity. Among these, the CatBoost model achieved the highest accuracy (R2 = 0.99). Feature analysis revealed that FTS operational conditions mainly affect CO conversion (37.9 %), while catalyst properties were primarily crucial for C8-C16 selectivity (40.6 %). The proposed ML framework provides a first powerful tool for the rational design of FTS catalysts and operating conditions to maximize jet fuel productivity. . KW - Jet fuels (C8-C16) KW - Machine learning (ML) KW - Fischer-Tropsch synthesis (FTS) KW - Operational conditions KW - Catalyst preparation Y1 - 2025 U6 - https://doi.org/10.1016/j.ceja.2024.100702 SN - 2666-8211 VL - 21 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Bernecker, Maximilian A1 - Gebhardt, Marc A1 - Amor, Souhir Ben A1 - Wolter, Martin A1 - Müsgens, Felix T1 - Quantifying the impact of load forecasting accuracy on congestion management in distribution grids JF - International Journal of Electrical Power and Energy Systems N2 - Digitalization is a global trend in energy systems and beyond. However, it is often unclear what digitalization means exactly in the context of energy systems and how the benefits of digitalization can be quantified. Providing additional information, e.g., through sensors and metering equipment, is one concrete angle where digitalization contributes. This paper provides a framework to quantify the value of such additional information in distribution grids. We analyze to what extent smart meters improve the accuracy of day-ahead load forecasts and quantify the savings in congestion management costs resulting from the improved accuracy. To quantify the cost reduction, we conduct a case study employing a simplified IEEE test system. Historical electricity load data from over 6,000 smart meters was used to improve day-ahead load forecasts. We assessed and compared the forecasting performance to estimates based on standard load profiles with multiple load forecast simulations in the network based on uncertainty parameterizations from forecasts with and without smart meter data. Calculating redispatch cost in the distribution grid, we find that the forecast based on smart meter data reduces key redispatch parameters such as the share of expected voltage violations, the amount of rescheduled generation by more than 90%. These improvements translate into a reduction in congestion management costs by around 97%. Furthermore, we shed light on whether the gains increase linearly with the number of smart meters and available data in the grid. When smart meter shares are increased uniformly throughout the grid, savings are concave, i.e., the first 10% of smart meters reduces congestion management costs by around 20% while the last 10% reduces these costs only marginally. Focusing smart meter installation on the most congested nodes reduces congestion management costs by around 60% with just 10% smart meter coverage, significantly outperforming a uniform rollout. However, savings in congestion management alone are not likely to recover the installation and operation costs of the installed smart meter. KW - Distribution Grid KW - Congestion management KW - Uncertainty KW - Forecasting KW - Smart Meter Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:co1-opus4-70351 SN - 1879-3517 SN - 0142-0615 VL - 168 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Hasanuzzaman, Gazi A1 - Eivazi, Hamidreza A1 - Merbold, Sebastian A1 - Egbers, Christoph A1 - Vinuesa, Ricardo T1 - Enhancement of PIV measurements via physics-informed neural networks T1 - Verbesserung von PIV-Messungen durch physikinformierte neuronale Netze N2 - Physics-informed neural networks (PINN) are machine-learning methods that have been proved to be very successful and effective for solving governing equations of fluid flow. In this work we develop a robust and efficient model within this framework and apply it to a series of two-dimensional three-component (2D3C) stereo particle-image velocimetry datasets, to reconstruct the mean velocity field and correct measurements errors in the data. Within this framework, the PINNsbased model solves the Reynolds-averaged-Navier-Stokes (RANS) equations for zeropressure-gradient turbulent boundary layer (ZPGTBL) without a prior assumption and only taking the data at the PIV domain boundaries. The TBL data has different flow conditions upstream of the measurement location due to the effect of an applied flow control via uniform blowing. The developed PINN model is very robust, adaptable and independent of the upstream flow conditions due to different rates of wall-normal blowing while predicting the mean velocity quantities simultaneously. Hence, this approach enables improving the mean-flow quantities by reducing errors in the PIV data. For comparison, a similar analysis has been applied to numerical data obtained from a spatially-developing ZPGTBL and an adverse-pressure-gradient (APG) TBL over a NACA4412 airfoil geometry. The PINNs-predicted results have less than 1% error in the streamwise velocity and are in excellent agreement with the reference data. This shows that PINNs has potential applicability to shear-driven turbulent flows with different flow histories, which includes experiments and numerical simulations for predicting high-fidelity data. N2 - Physikalisch informierte neuronale Netze (PINN) sind Methoden des maschinellen Lernens, die sich als sehr erfolgreich und effektiv bei der Lösung von Strömungsgleichungen erwiesen haben. In dieser Arbeit entwickeln wir ein robustes und effizientes Modell in diesem Rahmen und wenden es auf eine Reihe von zweidimensionalen Drei-Komponenten-Stereo-Partikel-Bild-Velocimetrie-Datensätzen (2D3C) an, um das mittlere Geschwindigkeitsfeld zu rekonstruieren und Messfehler in den Daten zu korrigieren. In diesem Rahmen löst das PINN-basierte Modell die Reynolds-gemittelten-Navier-Stokes-Gleichungen (RANS) für die turbulente Grenzschicht mit Null-Druckgradienten (ZPGTBL) ohne vorherige Annahmen und nur unter Verwendung der Daten an den PIV-Domänengrenzen. Die TBL-Daten weisen unterschiedliche Strömungsbedingungen stromaufwärts des Messortes auf, was auf die Wirkung einer angewandten Strömungskontrolle durch gleichmäßiges Blasen zurückzuführen ist. Das entwickelte PINN-Modell ist sehr robust, anpassungsfähig und unabhängig von den stromaufwärts gelegenen Strömungsbedingungen aufgrund unterschiedlicher Raten des Wandnormalblasens bei gleichzeitiger Vorhersage der mittleren Geschwindigkeitsgrößen. Daher ermöglicht dieser Ansatz eine Verbesserung der mittleren Strömungsgrößen durch Reduzierung der Fehler in den PIV-Daten. Zum Vergleich wurde eine ähnliche Analyse auf numerische Daten angewandt, die von einer sich räumlich entwickelnden ZPGTBL und einer TBL mit ungünstigem Druckgradienten (APG) über einer NACA4412-Schaufelgeometrie gewonnen wurden. Die von PINNs vorhergesagten Ergebnisse haben einen Fehler von weniger als 1% in der Strömungsgeschwindigkeit und stimmen hervorragend mit den Referenzdaten überein. Dies zeigt, dass PINNs das Potenzial hat KW - Machine learning KW - Particle image velocimetry KW - Turbulent boundary layer KW - Large Eddy Simulation KW - Measurement KW - Maschinelles Lernen KW - Turbulente Grenzschicht KW - Physikalisch informiertes neuronales Netz KW - Messung KW - Turbulente Grenzschicht KW - Neuronales Netz KW - Maschinelles Lernen KW - Particle-Image-Velocimetry Y1 - 2022 U6 - https://doi.org/10.1088/1361-6501/aca9eb ER - TY - JOUR A1 - Hasanuzzaman, Gazi A1 - Buchwald, Tom A1 - Schunk, Christoph A1 - Schröder, Andreas A1 - Egbers, Christoph A1 - Hampel, Uwe T1 - DATIV - Remote enhancement of smart aerosol measurement system using Raspberry Pi based distributed sensors JF - Sensors N2 - Enclosed public spaces are the hotspots for airborne disease transmission. To measure and maintain indoor air quality in terms of airborne transmission, an open source, low cost and distributed array of Particulate Matter Sensors has been developed and named as Dynamic Aerosol Transport for Indoor Ventilation or DATIV system. This system can use multiple Particulate Matter Sensors (PMS) simultaneously and can be remotely controlled using a Raspberry Pie based operating system. The data acquisition system can be easily operated using the GUI within any common browser installed on a remote device such as a PC or Smartphone with corresponding IP address. The software architecture and validation measurements are presented together with possible future developments. KW - Particulate matter KW - Aerosol KW - Low cost measurement system KW - Distributed sensors KW - Indoor ventilation Y1 - 2024 U6 - https://doi.org/10.3390/s24134314 SN - 1424-8220 VL - 24 IS - 13 PB - MDPI CY - Basel ER - TY - JOUR A1 - Barth, Maximilian A1 - Werner, Magdalena A1 - Otto, Pascal A1 - Richwien, Benjamin A1 - Bahramsari, Samira A1 - Krause, Maximilian A1 - Schwan, Benjamin A1 - Abendroth, Christian T1 - Microwave‑assisted organic acids and green hydrogen production during mixed culture fermentation JF - Biotechnology for Biofuels and Bioproducts N2 - Background The integration of anaerobic digestion into bio-based industries can create synergies that help render anaerobic digestion self-sustaining. Two-stage digesters with separate acidification stages allow for the production of green hydrogen and short-chain fatty acids, which are promising industrial products. Heat shocks can be used to foster the production of these products, the practical applicability of this treatment is often not addressed sufficiently, and the presented work therefore aims to close this gap. Batch experiments were conducted in 5 L double-walled tank reactors incubated at 37 °C. Short microwave heat shocks of 25 min duration and exposure times of 5–10 min at 80 °C were performed and compared to oven heat shocks. Pairwise experimental group differences for gas production and chemical parameters were determined using ANOVA and post–hoc tests. High-throughput 16S rRNA gene amplicon sequencing was performed to analyse taxonomic profiles. After heat–shocking the entire seed sludge, the highest hydrogen productivity was observed at a substrate load of 50 g/l with 1.09 mol H2/ mol hexose. With 1.01 mol H2/ mol hexose, microwave-assisted treatment was not significantly different from oven-based treatments. This study emphasised the better repeatability of heat shocks with microwave-assisted experiments, revealing low variation coefficients averaging 29%. The pre-treatment with microwaves results in a high predictability and a stronger microbial community shift to Clostridia compared to the treatment with the oven. The pre-treatment of heat shocks supported the formation of butyric acid up to 10.8 g/l on average, with a peak of 24.01 g/l at a butyric/acetic acid ratio of 2.0. The results support the suitability of using heat shock for the entire seed sludge rather than just a small inoculum, making the process more relevant for industrial applications. The performed microwave-based treatment has proven to be a promising alternative to oven-based treatments, which ultimately may facilitate their implementation into industrial systems. This approach becomes economically sustainable with high temperature heat pumps with a coefficient of performance (COP) of 4.3. KW - Acidification KW - Hydrogen production KW - Volatile fatty acids production KW - Microwave heat shocks KW - 16-S-rRNA sequencing Y1 - 2024 U6 - https://doi.org/10.1186/s13068-024-02573-7 SN - 2731-3654 VL - 17 PB - BMC CY - London ER - TY - CHAP A1 - Bhutani, A. A1 - Boes, F. A1 - Goettel, B. A1 - Schaefer, J. A1 - Eisenbeis, J. A1 - Zwick, T. A1 - Malz, Stefan A1 - Rodriguez Vazquez, Pedro A1 - Grzyb, Janusz A1 - Pfeiffer, Ulrich T1 - Real100G.RF : a fully integrated, multi-purpose radio front-end for wireless 100 Gbps T1 - Real100G.RF : eine vollständig integrierte, vielseitig anwendbare Funkeingangsstufe für Funk bei 100 Gbps T2 - Wireless 100 Gbps and beyond : architectures, approaches and findings of German Research Foundation (DFG) Priority Programme SPP1655 N2 - In 2012 a group of researchers proposed a basic research initiative to the German Research Foundation (DFG) as a special priority project (SPP) with the name: Wireless 100 Gbps and beyond. The main goal of this initiative was the investigation of architectures, technologies and methods to go well beyond the state of the art. The target of 100 Gbps was set far away from the (at that time) achievable 1 Gbps such that it was not possible to achieve promising results just by tuning some parameters. We wanted to find breakthrough solutions. When we started the work on the proposal we discussed the challenges to be addressed in order to advancing the wireless communication speed significantly. Having the fundamental Shannon boundary in mind we discussed how to achieve the 100 Gbps speed. N2 - Angesichts der rapiden Entwicklung der Funkkommunikation hat die Deutsche Forschungsgemeinschaft im Jahr 2012 ein Schwerpunktprogramm mit dem Titel "Wireless 100 Gbps and beyound" (dt.: Drahtloskommunikation mit 100 Gbps und mehr) gestartet. Diese Initiative zielte auf neue Lösungen, Methoden und neues Wissen zur Lösung des Problems des kontinuierlichen Bedarfs an immer höheren Datenraten im Bereich der Funkkommunikation. Eine international besetze Jury hat etliche Projektvorschläge evaluiert, aus denen 11 Projekte ausgewählt und über zweimal 3 Jahre von Mitte 2013 bis Mitte 2019 gefördert wurden. Das vorliegende Buch versammelt die Ansätze, Architekturen und Erkenntnisse der Projekte. Es überspannt einen breiten Themenbereich, angefangen mit speziellen Fragen der physikalischen Übertragung, des Antennendesigns und der HF-Eingangs-Architekturen für unterschiedliche Frequenzbereiche bis 240 GHz. Darüber hinaus beschreibt das Buch Ansätze für Ultra-Hochgeschwindigkeits-Funksysteme, deren Basisbandverarbeitung, Kodierung sowie mögliche Umsetzungen. Nicht zuletzt wurden auch Fragen des Protokolldesigns behandelt, um eine enge Integration in moderne Computersysteme zu erleichtern. KW - 100 Gbps KW - Wireless KW - Drahtlos KW - Real100G.RF KW - Fully integrated KW - Multi-purpose radio front-end KW - Vollständig integriert KW - Vielseitig anwendbare Funkeingangsstufe KW - Drahtloses Sensorsystem KW - Hochfrequenztechnik KW - Antenne KW - Terahertzbereich KW - Energieffizienz Y1 - 2020 U6 - https://doi.org/10.26127/BTUOpen-5915 SP - 295 EP - 354 ER - TY - CHAP A1 - Büchner, Steffen A1 - Nolte, Jörg A1 - Hasani, Alireza A1 - Kraemer, Rolf A1 - Lopacinsiki, Lukasz T1 - End2End100 : communication protocol processing for ultra high data rates T1 - End2End100 : Kommunikations-Protokoll–Prozessierung für ultrahohe Datenraten T2 - Wireless 100 Gbps and beyond : architectures, approaches and findings of German Research Foundation (DFG) Priority Programme SPP1655 N2 - In 2012 a group of researchers proposed a basic research initiative to the German Research Foundation (DFG) as a special priority project (SPP) with the name: Wireless 100 Gbps and beyond. The main goal of this initiative was the investigation of architectures, technologies and methods to go well beyond the state of the art. The target of 100 Gbps was set far away from the (at that time) achievable 1 Gbps such that it was not possible to achieve promising results just by tuning some parameters. We wanted to find breakthrough solutions. When we started the work on the proposal we discussed the challenges to be addressed in order to advancing the wireless communication speed significantly. Having the fundamental Shannon boundary in mind we discussed how to achieve the 100 Gbps speed. N2 - Angesichts der rapiden Entwicklung der Funkkommunikation hat die Deutsche Forschungsgemeinschaft im Jahr 2012 ein Schwerpunktprogramm mit dem Titel "Wireless 100 Gbps and beyound" (dt.: Drahtloskommunikation mit 100 Gbps und mehr) gestartet. Diese Initiative zielte auf neue Lösungen, Methoden und neues Wissen zur Lösung des Problems des kontinuierlichen Bedarfs an immer höheren Datenraten im Bereich der Funkkommunikation. Eine international besetze Jury hat etliche Projektvorschläge evaluiert, aus denen 11 Projekte ausgewählt und über zweimal 3 Jahre von Mitte 2013 bis Mitte 2019 gefördert wurden. Das vorliegende Buch versammelt die Ansätze, Architekturen und Erkenntnisse der Projekte. Es überspannt einen breiten Themenbereich, angefangen mit speziellen Fragen der physikalischen Übertragung, des Antennendesigns und der HF-Eingangs-Architekturen für unterschiedliche Frequenzbereiche bis 240 GHz. Darüber hinaus beschreibt das Buch Ansätze für Ultra-Hochgeschwindigkeits-Funksysteme, deren Basisbandverarbeitung, Kodierung sowie mögliche Umsetzungen. Nicht zuletzt wurden auch Fragen des Protokolldesigns behandelt, um eine enge Integration in moderne Computersysteme zu erleichtern. KW - 100 Gbps KW - Wireless KW - Drahtlos KW - End2End100 KW - Communication protocol processing KW - Kommunikations-Protokoll–Prozessierung KW - Drahtloses Sensorsystem KW - Hochfrequenztechnik KW - Antenne KW - Terahertzbereich KW - Energieffizienz Y1 - 2020 U6 - https://doi.org/10.26127/BTUOpen-5916 SP - 359 EP - 396 ER - TY - CHAP A1 - Johannsen, Nils L. A1 - Hoeher, Peter A. A1 - Peitzmeier, Nikolai A1 - Manteuffel, Dirk T1 - M4 : multi-mode massive MIMO T1 - M4 : Multi-Mode-massiv-MIMO T2 - Wireless 100 Gbps and beyond : architectures, approaches and findings of German Research Foundation (DFG) Priority Programme SPP1655 N2 - In 2012 a group of researchers proposed a basic research initiative to the German Research Foundation (DFG) as a special priority project (SPP) with the name: Wireless 100 Gbps and beyond. The main goal of this initiative was the investigation of architectures, technologies and methods to go well beyond the state of the art. The target of 100 Gbps was set far away from the (at that time) achievable 1 Gbps such that it was not possible to achieve promising results just by tuning some parameters. We wanted to find breakthrough solutions. When we started the work on the proposal we discussed the challenges to be addressed in order to advancing the wireless communication speed significantly. Having the fundamental Shannon boundary in mind we discussed how to achieve the 100 Gbps speed. N2 - Angesichts der rapiden Entwicklung der Funkkommunikation hat die Deutsche Forschungsgemeinschaft im Jahr 2012 ein Schwerpunktprogramm mit dem Titel "Wireless 100 Gbps and beyound" (dt.: Drahtloskommunikation mit 100 Gbps und mehr) gestartet. Diese Initiative zielte auf neue Lösungen, Methoden und neues Wissen zur Lösung des Problems des kontinuierlichen Bedarfs an immer höheren Datenraten im Bereich der Funkkommunikation. Eine international besetze Jury hat etliche Projektvorschläge evaluiert, aus denen 11 Projekte ausgewählt und über zweimal 3 Jahre von Mitte 2013 bis Mitte 2019 gefördert wurden. Das vorliegende Buch versammelt die Ansätze, Architekturen und Erkenntnisse der Projekte. Es überspannt einen breiten Themenbereich, angefangen mit speziellen Fragen der physikalischen Übertragung, des Antennendesigns und der HF-Eingangs-Architekturen für unterschiedliche Frequenzbereiche bis 240 GHz. Darüber hinaus beschreibt das Buch Ansätze für Ultra-Hochgeschwindigkeits-Funksysteme, deren Basisbandverarbeitung, Kodierung sowie mögliche Umsetzungen. Nicht zuletzt wurden auch Fragen des Protokolldesigns behandelt, um eine enge Integration in moderne Computersysteme zu erleichtern. KW - 100 Gbps KW - Wireless KW - Drahtlos KW - M4 KW - Multi-mode massive MIMO KW - Multi-Mode-massiv-MIMO KW - Drahtloses Sensorsystem KW - Hochfrequenztechnik KW - Antenne KW - Terahertzbereich KW - Energieffizienz Y1 - 2020 U6 - https://doi.org/10.26127/BTUOpen-5912 SP - 167 EP - 212 ER - TY - CHAP A1 - Scheytt, J. Christoph A1 - Javed, Abdul Rehman A1 - Bhutani, Akanksha A1 - Zwick, Thomas A1 - Kallfass, Ingmar A1 - Bamidi, Eswara Rao A1 - Krishnegowda, Karthik A1 - Kraemer, Rolf T1 - Real100G : ultrabroadband wireless communication at high mm-wave frequencies T1 - Real100G : Ultrabreitband-drahtlos-Kommunikation im hohen Mm-Wellen-Bereich T2 - Wireless 100 Gbps and beyond : architectures, approaches and findings of German Research Foundation (DFG) Priority Programme SPP1655 N2 - In 2012 a group of researchers proposed a basic research initiative to the German Research Foundation (DFG) as a special priority project (SPP) with the name: Wireless 100 Gbps and beyond. The main goal of this initiative was the investigation of architectures, technologies and methods to go well beyond the state of the art. The target of 100 Gbps was set far away from the (at that time) achievable 1 Gbps such that it was not possible to achieve promising results just by tuning some parameters. We wanted to find breakthrough solutions. When we started the work on the proposal we discussed the challenges to be addressed in order to advancing the wireless communication speed significantly. Having the fundamental Shannon boundary in mind we discussed how to achieve the 100 Gbps speed. N2 - Angesichts der rapiden Entwicklung der Funkkommunikation hat die Deutsche Forschungsgemeinschaft im Jahr 2012 ein Schwerpunktprogramm mit dem Titel "Wireless 100 Gbps and beyound" (dt.: Drahtloskommunikation mit 100 Gbps und mehr) gestartet. Diese Initiative zielte auf neue Lösungen, Methoden und neues Wissen zur Lösung des Problems des kontinuierlichen Bedarfs an immer höheren Datenraten im Bereich der Funkkommunikation. Eine international besetze Jury hat etliche Projektvorschläge evaluiert, aus denen 11 Projekte ausgewählt und über zweimal 3 Jahre von Mitte 2013 bis Mitte 2019 gefördert wurden. Das vorliegende Buch versammelt die Ansätze, Architekturen und Erkenntnisse der Projekte. Es überspannt einen breiten Themenbereich, angefangen mit speziellen Fragen der physikalischen Übertragung, des Antennendesigns und der HF-Eingangs-Architekturen für unterschiedliche Frequenzbereiche bis 240 GHz. Darüber hinaus beschreibt das Buch Ansätze für Ultra-Hochgeschwindigkeits-Funksysteme, deren Basisbandverarbeitung, Kodierung sowie mögliche Umsetzungen. Nicht zuletzt wurden auch Fragen des Protokolldesigns behandelt, um eine enge Integration in moderne Computersysteme zu erleichtern. KW - 100 Gbps KW - Wireless KW - Drahtlos KW - Real100G KW - Ultrabroadband wireless communication KW - Ultrabreitband-drahtlos-Kommunikation KW - Drahtloses Sensorsystem KW - Hochfrequenztechnik KW - Antenne KW - Terahertzbereich KW - Energieffizienz Y1 - 2020 U6 - https://doi.org/10.26127/BTUOpen-5913 SP - 213 EP - 230 ER - TY - JOUR A1 - Dikra, Bouras A1 - Fellah, Mamoun A1 - Barille, Regis A1 - Weiß, Sabine A1 - Samad, Mohammed Abdul A1 - Alburaikan, Alhanouf A1 - Khalifa, Hamiden Abd El-Wahed A1 - Obrosov, Aleksei T1 - Improvement of photocatalytic performance and sensitive ultraviolet photodetectors using AC-ZnO/ZC-Ag2O/AZ-CuO multilayers nanocomposite prepared by spin coating method T1 - Verbesserung der photokatalytischen Leistung empfindlicher Ultraviolett-Photodetektoren unter Verwendung von AC-ZnO/ZC-Ag2O/AZ-CuO-Multilayer-Nanokompositen abgeschieden durch Rotationsbeschichtung JF - Journal of science: advanced materials and devices N2 - Morphological and optical properties of a multilayer film (CAZO/CZAO/ZACO) prepared by spin-coating method and deposited on a glass substrate were evaluated. The study was initially carried out for each layer, individually and then as a multilayer subsequently. Structural properties using X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), infrared spectra (IR) and X-ray photoelectron Spectroscopy (XPS) showed the presence of three phases of zinc, copper and silver oxides at different levels. The CZAO sample observed with scanning electron microscope (SEM) showed an excellent porous surface with a large deformation in the multilayer configuration. Doping with zinc and copper in the silver crystal lattice improved the crystal structure and reduced the optical energy gap, thus increasing the optical absorbance and refractive index. The dielectric constants and showed an increase in the optical polarization values for lower photonic energies. The maximum degradation rate for photocatalysts of methylene blue was 89 % for a 5-h exposure period with CAZO/CZAO/ZACO while it reached 71 % for the CZAO sample during the same time period. The sensitivity of samples to light proved that the presence of ultraviolet radiation increases the number of holes trapped by oxygen ions and causes more free electrons and contribute to a better production of photocurrent than in darkness. N2 - Die morphologischen und optischen Eigenschaften eines mehrlagigen Films (CAZO/CZAO/ZACO), der im Rotationsbeschichtungsverfahren hergestellt und auf ein Glas-Substrat aufgebracht wurde, wurden bewertet. Die Studie wurde zunächst für jede Schicht einzeln und anschließend als Multilagenbeschichtung durchgeführt. Die strukturellen Eigenschaften mittels Röntgenbeugung (XRD), energiedispersiver Röntgenspektroskopie (EDS), Infrarotspektren (IR) und Röntgenphotoelektronenspektroskopie (XPS) zeigten das Vorhandensein von drei Phasen aus Zink-, Kupfer- und Silberoxiden auf verschiedenen Ebenen. Die mit dem Rasterelektronenmikroskop (REM) untersuchte CZAO-Probe zeigte eine ausgezeichnete poröse Oberfläche mit einer großen Verformung in der Multischichtkonfiguration. Die Dotierung des Silberkristallgitters mit Zink und Kupfer verbesserte die Kristallstruktur und verringerte die optische Energielücke, wodurch sich die optische Absorption und der Refraktionsindex erhöhten. Die Dielektrizitätskonstanten und die optischen Polarisationswerte stiegen bei niedrigeren Photonenergien an. Die maximale Abbaugeschwindigkeit der Photokatalysatoren für Methylenblau betrug 89 % bei einer 5-stündigen Belichtungszeit mit CAZO/CZAO/ZACO, während sie bei der CZAO-Probe im gleichen Zeitraum 71 % erreichte. Die Lichtempfindlichkeit der Proben beweist, dass das Vorhandensein von ultravioletter Strahlung die Anzahl der von Sauerstoffionen eingefangenen Löcher erhöht und mehr freie Elektronen verursacht, die zu einer besseren Produktion von Photostrom beitragen als bei Dunkelheit. KW - Multilayer CAZO/CZAO/ZACO KW - Photocatalysis KW - Photodetector KW - Nanostructures KW - Nanocomposites KW - Multilagenbeschichtung CAZO/CZAO/ZACO KW - Rotationsbeschichtung KW - Photokatalyse KW - Nanostrukturen KW - Nanokompositen KW - Nanokomposit KW - Mehrschichtsystem KW - Beschichtung KW - Fotokatalyse KW - Photodetektor Y1 - 2023 U6 - https://doi.org/10.1016/j.jsamd.2023.100642 SN - 2468-2179 VL - 9 IS - 1 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Konda, Karunakar Reddy A1 - Franzki, Jonas A1 - Sharma, Dikshant A1 - König, Paul A1 - Mathiazhagan, Akilan A1 - Henke, Markus A1 - Höschler, Klaus T1 - Quantitative assessment of cooling methods for electrical machines in aircraft drives JF - IEEE Access N2 - Transformation of the aviation sector towards climate-neutral solutions such as electrification is urgent. Aviation electrification requires reasoned selection of suitable technologies which has to meet strict requirements and standards. Cooling of electrical components plays a vital role in the sizing and overall performance of the electrical drive system and must achieve high effectiveness and reliability at low weight. Three cooling methods – air cooling, direct slot cooling and cooling jacket – are sized for a 300 kW commuter aircraft (CS23) all-electric propulsion system. They are further evaluated quantitatively for weight, drag, reliability and effectiveness in a conservative assessment. A lumped parameter thermal network (LPTN) approach is utilized to assess and evaluate the thermal performance of the cooling systems. The LPTN model served as the basis to determine the temperature limits and capabilities of the cooling system which are then utilized to size the auxiliary components. Reliability is assessed via fault tree analysis, drag via scoop inlet characteristics and effectiveness via the heat load dissipated per weight of the system and the required cooling power per mechanical power. Cooling jacket achieves the highest effectiveness closely followed by slot cooling. Air cooling proves to be most reliable and lightest. KW - Cooling systems KW - Electric aircrafts KW - Motor drives KW - Sizing KW - Thermal management Y1 - 2024 U6 - https://doi.org/10.1109/ACCESS.2024.3517319 SN - 2169-3536 VL - 12 SP - 192768 EP - 192785 PB - IEEE CY - New York ER - TY - JOUR A1 - Dahmani, Maewa A1 - Fellah, Mamoun A1 - Hezil, Naouel A1 - Benoudia, Mohamed-Cherif A1 - Obrosov, Aleksei A1 - El-Hiti, Gamal A. A1 - Weiss, Sabine T1 - Bioactivity and tribological performance of a novel nano-biomaterial beta-type Ti-alloy JF - Journal of Materials Research and Technology N2 - This study investigates the bioactivity; wear performance, and topography of a novel beta-type titanium-based alloy using techniques such as scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and 2D and 3D analysis. The tribological test was evaluated using a ball-on-disk tribometer in a wet environment. Different loads of 2, 6, and 10 N were applied during the evolution. The data results indicate a significant effect of the milling process on the formation of the hydroxyapatite layer on the surfaces of the Ti–Nb–Mo alloy. Both the wear volume and rate showed a consistent trend of decrease as the milling time increased from 2 to 12 h for all applied loads. The minimum values of wear and volume were reached after 12 h of milling. The improvement in tribological behavior can be attributed to the improved mechanical properties of the alloys. In addition, the significant presence of niobium (Nb) and molybdenum (Mo) plays a critical role in achieving high coefficient of friction values. The primary wear mechanism observed in the Ti–25Nb–25Mo system was adhesive wear in addition to abrasive wear. With its lower Young’s modulus and favorable biological and tribological properties, the Ti–25Nb–25Mo alloy represents a promising option for bone tissue applications in orthopedics. KW - Ti–25Nb–25Mo KW - Milling time KW - Bioactivity KW - Hydroxyapatite KW - Friction coefficient Y1 - 2025 U6 - https://doi.org/10.1016/j.jmrt.2025.03.180 SN - 2214-0697 VL - 36 SP - 2297 EP - 2316 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Buchwald, Tom A1 - Hasanuzzman, Gazi A1 - Merbold, Sebastian A1 - Schanz, Daniel A1 - Egbers, Christoph A1 - Schröder, Andreas T1 - Large-scale flow field and aerosol particle transport investigations in a classroom using 2D-Shake-The-Box Lagrangian Particle Tracking T1 - Großräumige Strömungsfeld- und Aerosolpartikeltransportuntersuchungen in einem Klassenzimmer mit 2D-Shake-The-Box Lagrangian Particle Tracking JF - Heliyon N2 - Infections with COVID-19 in enclosed public spaces, where virus-laden aerosol particles can accumulate over time, have significantly contributed to the rapid spread of the virus. It is therefore of great importance to understand the transport and dispersion process of aerosol particles in such spaces, especially against the background of future pandemics. In this work, we present a Lagrangian-Particle-Tracking experiment to assess the mixed convective flow in a classroom with different ventilation strategies. For this purpose, thermal plumes were created by heated dummies, and a collimated LED light-sheet with ~0.4 m thickness was used for illumination of helium filled soap bubbles (HFSB) acting as passive tracer particles. In this way, the Lagrangian trajectories of the particles were recorded at two approximately 4.2 m × 2.8 m large fields using the novel 2D-Shake-The-Box-Method. As a result, time-resolved trajectories of over 300,000 simultaneously tracked HFSB have been reconstructed, so that both small-scale and large-scale properties of the flow are visualized quantitatively across the entire cross-section of the room. The trajectories show that the thermal plumes create lengthwise circulating vortices, which cannot be destroyed across the entire cross-section of the room by opening or tilting a window. Furthermore, the mixing in the room through the operation of an air purifier is higher compared to opening a window, which suggests that this strategy in combination with its air filtering capability is the most effective strategy to prevent infections. N2 - Infektionen mit COVID-19 in geschlossenen öffentlichen Räumen, in denen sich virushaltige Aerosolpartikel mit der Zeit ansammeln können, haben erheblich zur raschen Ausbreitung des Virus beigetragen. Es ist daher von großer Bedeutung, den Transport- und Ausbreitungsprozess von Aerosolpartikeln in solchen Räumen zu verstehen, insbesondere vor dem Hintergrund künftiger Pandemien. In dieser Arbeit stellen wir ein Lagrangian-Particle-Tracking-Experiment vor, um die gemischt-konvektive Strömung in einem Klassenzimmer mit verschiedenen Lüftungsstrategien zu untersuchen. Zu diesem Zweck wurden Wärmefahnen durch beheizte Dummys erzeugt und eine kollimierte LED-Lichtplatte mit einer Dicke von ~0,4 m beleuchtete mit Helium gefüllte Seifenblasen (HFSB), die als passive Tracerpartikel fungierten. Auf diese Weise konnten die Lagrange'schen Trajektorien der Partikel in zwei etwa 4,2 m × 2,8 m großen Feldern mit der neuartigen 2D-Shake-The-Box-Methode aufgezeichnet werden. Als Ergebnis wurden zeitaufgelöste Trajektorien von über 300.000 gleichzeitig verfolgten HFSB rekonstruiert, so dass sowohl kleinräumige als auch großskalige Eigenschaften der Strömung über den gesamten Querschnitt des Raumes quantitativ visualisiert werden. Die Trajektorien zeigen, dass die Wärmefahnen in Längsrichtung zirkulierende Wirbel erzeugen, die auch durch Öffnen oder Kippen eines Fensters nicht über den gesamten Raumquerschnitt zerstört werden können. Außerdem ist die Durchmischung im Raum durch den Betrieb eines Luftreinigers höher im Vergleich zum Öffnen eines Fensters, was darauf hindeutet, dass diese Strategie in Kombination mit ihrer Luftfilterung die wirksamste Strategie zur Vermeidung von Infektionen ist. KW - Shake-the-box KW - Lagrangian-particle-tracking KW - Aerosol particle spreading KW - Room ventilation KW - Covid-19 KW - Lagrangesche Partikelverfolgung KW - Ausbreitung von Aerosolpartikeln KW - Raumbelüftung KW - Aerosol KW - Lagrange-Darstellung KW - Belüftung KW - Klassenzimmer Y1 - 2023 U6 - https://doi.org/10.1016/j.heliyon.2023.e22826 SN - 2405-8440 VL - 9 IS - 12 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Lee, Roh Pin A1 - Reb, Jochen T1 - “Waste-to-Products” for the sustainability transformation of megacities : case analysis of impacts of public knowledge and perception on chemical recycling deployment in Singapore JF - Cleaner Waste Systems N2 - Megacities generate significant amounts of unsorted domestic waste. Rather than being landfilled/incinerated, this could be used to substitute fossil resources for chemical production via chemical recycling (CR). CR thus represents an opportunity for a parallel achievement of multiple sustainability goals from resource efficiency, decarbonization to circularity and sustainable waste management. However, as an emerging technology, its potential contributions to a nation’s sustainability transformation remain debated. While extant literature in the fields of waste management and CR have predominantly focused on waste sorting/segregation/collection as well as techno-economical-ecological feasibility of CR technologies respectively, insights into human factors which could hinder CR deployment in the forms of pyrolysis and gasification for the sustainable waste management in megacities remain lacking. To address this gap, this study implemented a representative online survey in Singapore – a megacity in Southeast Asia aiming to transit towards circularity and zero-waste by 2030 – and enabled first and novel insights into factors in the human dimension which would (1) influence proper waste separation/recycling behaviors – a prerequisite for the successful implementation of waste pyrolysis, and (2) impact societal support for using domestic waste for chemical production via waste gasification rather than for energy production via waste incineration – the dominant waste management approach in Singapore. Study insights regarding the impacts of the human factor and the identified opportunities for CR integration in a nation’s waste system – besides extending extant waste management and CR literature – furthermore act as a blueprint for sustainable waste management and green chemistry for the sustainability transformation of other megacities. KW - Chemical recycling KW - Waste pyrolysis KW - Waste gasification KW - Domestic waste KW - Perception Y1 - 2025 U6 - https://doi.org/10.1016/j.clwas.2025.100359 SN - 2772-9125 VL - 12 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Ertugrul, Gökhan A1 - Emdadi, Aliakbar A1 - Jedynak, Angelika A1 - Weiß, Sabine A1 - Härtel, Sebastian T1 - Hot forming behavior of tungsten carbide reinforced Ni-based superalloy 625 additively manufactured by laser directed energy deposition JF - Additive Manufacturing Letters N2 - The demands of high-performance industries such as aerospace, automotive, tool manufacturing, oil, and gas industries are driving the innovation in high-performance materials and their production methods. This study explores the impact of hybrid manufacturing, specifically the effect of the addition of tungsten carbide (WC/W2C) via Laser-Directed Energy Deposition (L-DED), on the hot workability, hardness, and microstructure of nickel-based superalloy Inconel 625 (IN625). IN625 is known for its high temperature and high corrosion resistance, and tungsten carbide for its high wear resistance and grain refinement effect. The integration of WC/W2C particles into the IN625 matrix, in addition to the use of the hybrid approach of additive manufacturing followed by a hot–forming process, significantly influences the microstructure and mechanical behavior of the material. Thus, while incorporation of the WC/W2C can strengthen the material and extend the mechanical limitations, its full impact, including any potential usages, should be thoroughly evaluated for the intended application of the materials. To understand the effect of WC/W2C, additive manufacturing of IN625 both with and without WC/W2C and isothermal hot compression was carried out. The objective is to analyze the differences in microstructure and properties between L-DED manufactured IN625, and WC-reinforced IN625, and their hot-forming behavior, focusing on the effects of WC addition and post-deformation on microstructure and mechanical properties. This work represents the first investigation into the effect of WC/W2C hard particles on the hot-forming process of additively manufactured Ni-based metal matrix composites. KW - Hybrid manufacturing KW - Laser-directed energy deposition (L-DED) KW - Hot-forming KW - Inconel 625 (In625) KW - Microstructure manipulation Y1 - 2025 U6 - https://doi.org/10.1016/j.addlet.2025.100267 SN - 2772-3690 VL - 13 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Alimov, Artem A1 - Sviridov, Alexander A1 - Jensch, Felix A1 - Sydow, Benjamin A1 - Härtel, Sebastian T1 - Additive manufacturing of hot-forming dies using laser powder bed fusion and wire arc direct energy deposition technologies T1 - Additive Fertigung von Warmumformwerkzeugen unter Verwendung von Laser Powder Bed Fusion und Wire Arc Direct Energy Deposition Technologien N2 - Additive technologies are now widely used for the production of complex precise parts and have high potential for the production of forming dies. In this work, hot-forming dies optimized for additive manufacturing were developed and produced with wire arc direct energy deposition (WA-DED) and laser powder bed fusion (L-PBF) technologies. The concept of lightweight hot-forming dies with a 2D-lattice structure was developed, which reduced the weight of each die by 56%, from 14.2 kg to 6.1 kg, in production using L-PBF. Maraging/precipitation-hardened steel 17-4PH was used as an alternative to traditional hot-working steels with slightly lower mechanical properties and a much higher processability in the additive manufacturing process. The workability of the manufactured dies was confirmed by forging tests on an industrial screw press. N2 - Additive Technologien sind derzeit für die Herstellung komplexer, präziser Teile weit verbreitet und weisen ein hohes Potenzial für die Herstellung von Umformwerkzeugen auf. In dieser Arbeit wurden Warmumformwerkzeuge, die für die additive Fertigung optimiert sind, entwickelt und mit den Technologien WA-DED (Wire Arc Direct Energy Deposition) und L-PBF (Laser Powder Bed Fusion) hergestellt. Es wurde ein Konzept für Leichtbau-Warmumformwerkzeuge mit einer 2D-Gitterstruktur entwickelt, das das Gewicht jedes Werkzeugs bei der Produktion mit L-PBF um 56 % von 14,2 kg auf 6,1 kg reduzierte. Als Alternative zu konventionellen Warmarbeitsstählen wurde der martensitische/ausscheidungsgehärtete Stahl 17-4PH verwendet, der geringfügig niedrigere mechanische Eigenschaften und eine wesentlich bessere Verarbeitbarkeit im additiven Fertigungsprozess aufweist. Die Verwendbarkeit der hergestellten Gesenke wurde durch Schmiedeversuche auf einer industriellen Schraubspindelpresse nachgewiesen. KW - Additive manufacturing KW - Hot-forming dies KW - L-PBF KW - WA-DED KW - WAAM KW - Additive Fertigung KW - Warmumformwerkzeuge KW - L-PBF KW - WA-DED KW - WAAM KW - Warmumformen KW - Rapid Prototyping (Fertigung) KW - Selektives Laserschmelzen Y1 - 2023 U6 - https://doi.org/10.3390/met13111842 VL - 13 IS - 11 PB - MDPI CY - Basel ER - TY - JOUR A1 - Grüger, Lennart A1 - Jensch, Felix A1 - Dittrich, Fabian A1 - Härtel, Sebastian T1 - On the creation of a material bond between L-PBF manufac-2tured AZ91 and Ti-6Al-4V components in the context of medi-3cal applications JF - Materials N2 - Within the scope of these investigations, the feasibility of a material bond between Ti-6Al-4V and the magnesium alloy AZ91 is analyzed. Ti-6Al-4V is frequently used for implants due to its biocompatibility, corrosion resistance, and specific strength. However, depending on the surface quality, the attachment behavior of the bone to the implant varies. Magnesium implants promote the regeneration of bone tissue and biodegrade as the bone tissue heals. Combining the properties of both materials in one implant enables a reduced implant volume and increased stability. For this reason, this study aims to demonstrate the feasibility of creating a material bond between the materials Ti-6Al-4V and AZ91. For this purpose, Ti-6Al-4V truncated cones and AZ91 sleeves were produced using the additive manufacturing process of laser powder bed fusion (L-PBF). The as-built sleeves were then pressed onto machined truncated cones. Since zinc serves as a lubricant and has good diffusion properties with the materials used as a result of heat treatment, a comparison was made between zinc-coated and the as-built Ti-6Al-4V samples. This showed that a bond was created after hot isostatic pressing and that the push-out force could be increased by more than 4.5 times. Consequently, a proof of feasibility was demonstrated, and a high potential for applications in medical technology was shown. KW - AZ91 KW - Ti-6Al-4V KW - Additive manufacturing KW - L-PBF KW - Implant technology Y1 - 2024 U6 - https://doi.org/10.3390/ma17184667 SN - 1996-1944 VL - 17 IS - 18 PB - MDPI CY - Basel ER - TY - JOUR A1 - Schütz, Raphael A1 - Reiss, Franzika A1 - Moor, Irene A1 - Kaman, Anna T1 - Lonely children and adolescents are less healthy and report less social support : a study on the effect of loneliness on mental health and the moderating role of social support JF - BMC Public Health N2 - Loneliness among children and adolescents has been increasingly recognized as a public health issue, for example, because of its associations with mental health problems. Nevertheless, there is a lack of evidence regarding the links between loneliness and mental health and the potential buffering role of social support. Thus, this study aims to investigate the prevalence of loneliness among children and adolescents in Germany and its associations with mental health. Furthermore, we analyze whether social support is negatively correlated with loneliness and mental health problems and whether it acts as a moderator of the association between loneliness and mental health issues. This study analyzed data from the Health Behavior in School-aged Children (HBSC) survey in Germany in 2022, which included 6,475 students aged 11, 13, and 15 years (girls: 50,6%, Mage = 13,4, SD = 1,7). Loneliness was measured via the University of California–Los Angeles Scale (UCLA) and a single-item measure. The mental health indicators included subjective health, life satisfaction, and multiple psychosomatic complaints. Social support from family, teachers, and classmates was assessed. Chi-square tests, t tests, logistic regressions, and moderation analyses were conducted. A total of 17.2% of the students reported high levels of loneliness. Compared with boys, girls and gender diverse students reported higher rates of loneliness. High levels of loneliness were strongly linked to poorer subjective health (OR = 5.56, p <.001), lower life satisfaction (OR = 7.32, p <.001), and increased psychosomatic complaints (OR = 7.38, p <.001). High social support from family, teachers, and students was associated with reduced loneliness and better mental health outcomes. Teacher support in grades 7 and 9 buffered the effect of loneliness on multiple psychosomatic complaints. The findings highlight that loneliness is a prevalent phenomenon among children and adolescents and is strongly associated with mental health issues. Greater social support is linked to reduced loneliness and better mental health, so targeted interventions to promote social support in schools and families are needed to address loneliness. Future research should explore longitudinal relationships and further elucidate the mechanisms underlying these associations. KW - Loneliness KW - Mental health KW - HBSC KW - Children KW - Adolescents Y1 - 2025 U6 - https://doi.org/10.1186/s12889-025-23247-5 SN - 1471-2458 VL - 25 PB - Springer Nature CY - Heidelberg ER - TY - JOUR A1 - Huber, Andreas A1 - Heinrichs, Harald A1 - Jaeger-Erben, Melanie T1 - Promoting neighbourhood sharing : infrastructures of convenience and community JF - Buildings & Cities N2 - Against the background of high levels of energy and resource demand in the residential sector, this paper investigates one potential way of making housing more sufficient: sharing at the neighbourhood level. Evidence from French and German case studies of ‘collaborative housing’ and ‘developer-driven neighbourhood sharing’ is used to identify two types of popular sharing practices: community-oriented and convenience-oriented. The first group of sharing practices is underpinned by creating, maintaining and experiencing social ties with neighbours. The second group of practices is guided by getting day-today tasks done smoothly and efficiently. To support the establishment of such sharing practices, some social and organisational measures are suggested. Thus, convenience-oriented sharing practices may be promoted by infrastructures and associated services that optimise the availability of sharing facilities and minimise temporal stretches and consumption work involved in practice performances. Community-oriented sharing practices may benefit from infrastructural arrangements that enable chance encounters, privilege community spaces over private areas and create welcoming spatial atmospheres. KW - Housing KW - Sustainability KW - Neighbourhood KW - Sharing KW - Sufficiency KW - Wohnen KW - Nachbarschaft KW - Suffizienz KW - Nachhaltigkeit Y1 - 2024 U6 - https://doi.org/10.5334/bc.442 SN - 2632-6655 VL - 5 IS - 1 SP - 349 EP - 367 PB - Ubiquity Press CY - London ER - TY - JOUR A1 - Geyer, Thomas A1 - Windisch, Thomas A1 - Fritsche, Christoph A1 - Sarradj, Ennes T1 - Dataset on permeability of wings from owls and non-silently flying birds T1 - Datensatz zur Luftdurchlässigkeit der Flügel von Eulen und nicht-leise fliegenden Vögeln N2 - The very soft and flow-permeable plumage is among the special adaptations of the owl that the silent flight is attributed to. Using a specially designed apparatus that provides a low-speed volume flow of air through a small sample of porous materials, measurements of the air flow permeability were performed in accordance to ISO 9053 on a total of 39 prepared wing specimen from six different bird species, including three species of silently flying owls and three non-silently flying bird species. The resulting data set described in the present paper contains the static airflow resistance measured at different positions on the wing. N2 - Das weiche und luftdurchlässige Gefieder der Eule ist eine der Anpassungen, die als verantwortlich für den leisen Flug der Eule gelten. In Anlehnung an ISO 9053 wurde die Durchlässigkeit des Eulengefieders mit Hilfe einer speziellen Messeinrichtung an insgesamt 39 präparierten Flügeln von 6 verschiedenen Vogelarten gemessen. Dazu gehörten drei Spezies von leise fliegenden Eulen sowie drei Spezies von nicht-leise fliegenden Vögeln. Der vorliegende Beitrag beschreibt den resultierenden Datensatz des an verschiedenen Flügelpositionen gemessenen Durchströmungswiderstands. KW - Owl wing KW - Air flow resistivity KW - Permeability KW - Silent flight KW - Acoustics KW - leiser Eulenflug KW - Strömungswiderstand KW - Permeabilität KW - Eulenflug KW - Akustik KW - Eulen KW - Vogelflug KW - Strömungswiderstand KW - Akustik KW - Permeabilität Y1 - 2023 U6 - https://doi.org/10.1016/j.dib.2023.109825 ER - TY - JOUR A1 - Azam, Hafiz Muhammad Husnain A1 - Rößling, Rosa Lise A1 - Geithe, Christiane A1 - Khan, Muhammad Moman A1 - Dinter, Franziska A1 - Hanack, Katja A1 - Prüß, Harald A1 - Husse, Britta A1 - Roggenbruck, Dirk A1 - Schierack, Peter A1 - Rödiger, Stefan T1 - MicroRNA biomarkers as next-generation diagnostic tools for neurodegenerative diseases : a comprehensive review JF - Frontiers in Molecular Neuroscience N2 - Neurodegenerative diseases (NDs) are characterized by abnormalities within neurons of the brain or spinal cord that gradually lose function, eventually leading to cell death. Upon examination of affected tissue, pathological changes reveal a loss of synapses, misfolded proteins, and activation of immune cells all indicative of disease progression before severe clinical symptoms become apparent. Early detection of NDs is crucial for potentially administering targeted medications that may delay disease advancement. Given their complex pathophysiological features and diverse clinical symptoms, there is a pressing need for sensitive and effective diagnostic methods for NDs. Biomarkers such as microRNAs (miRNAs) have been identified as potential tools for detecting these diseases. We explore the pivotal role of miRNAs in the context of NDs, focusing on Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, Huntington’s disease, and Amyotrophic Lateral Sclerosis. The review delves into the intricate relationship between aging and NDs, highlighting structural and functional alterations in the aging brain and their implications for disease development. It elucidates how miRNAs and RNA-binding proteins are implicated in the pathogenesis of NDs and underscores the importance of investigating their expression and function in aging. Significantly, miRNAs exert substantial influence on post-translational modifications (PTMs), impacting not just the nervous system but a wide array of tissues and cell types as well. Specific miRNAs have been found to target proteins involved in ubiquitination or deubiquitination processes, which play a significant role in regulating protein function and stability. We discuss the link between miRNA, PTM, and NDs. Additionally, the review discusses the significance of miRNAs as biomarkers for early disease detection, offering insights into diagnostic strategies. KW - Neurodegenerative diseases KW - MicroRNA KW - Diagnostic tools KW - Therapeutic tools KW - Protein post-translational modifications KW - Nervendegeneration KW - Biomarker KW - miRNS KW - Diagnose KW - Posttranslationale Änderung Y1 - 2024 U6 - https://doi.org/10.3389/fnmol.2024.1386735 SN - 1662-5099 VL - 17 PB - Frontiers CY - Lausanne ER - TY - CHAP A1 - Testa, Paolo Valerio A1 - Carta, Corrado A1 - Ellinger, Frank A1 - Klein, Bernhard A1 - Hahnel, Ronny A1 - Plettemeier, Dirk T1 - DAAB : on-chip integrated distributed amplifier and antenna systems in locally-backside-etched SiGe BiCMOS for receivers with ultra-large bandwidth T1 - DAAB : on-Chip-integrierte verteilte Verstärker- und Antennen-Systeme mit Lokaler-Rückseiten-Ätztechnologie SiGe BiCMOS für Empfänger mit ultrabreiter Bandbreite T2 - Wireless 100 Gbps and beyond : architectures, approaches and findings of German Research Foundation (DFG) Priority Programme SPP1655 N2 - In 2012 a group of researchers proposed a basic research initiative to the German Research Foundation (DFG) as a special priority project (SPP) with the name: Wireless 100 Gbps and beyond. The main goal of this initiative was the investigation of architectures, technologies and methods to go well beyond the state of the art. The target of 100 Gbps was set far away from the (at that time) achievable 1 Gbps such that it was not possible to achieve promising results just by tuning some parameters. We wanted to find breakthrough solutions. When we started the work on the proposal we discussed the challenges to be addressed in order to advancing the wireless communication speed significantly. Having the fundamental Shannon boundary in mind we discussed how to achieve the 100 Gbps speed. N2 - Angesichts der rapiden Entwicklung der Funkkommunikation hat die Deutsche Forschungsgemeinschaft im Jahr 2012 ein Schwerpunktprogramm mit dem Titel "Wireless 100 Gbps and beyound" (dt.: Drahtloskommunikation mit 100 Gbps und mehr) gestartet. Diese Initiative zielte auf neue Lösungen, Methoden und neues Wissen zur Lösung des Problems des kontinuierlichen Bedarfs an immer höheren Datenraten im Bereich der Funkkommunikation. Eine international besetze Jury hat etliche Projektvorschläge evaluiert, aus denen 11 Projekte ausgewählt und über zweimal 3 Jahre von Mitte 2013 bis Mitte 2019 gefördert wurden. Das vorliegende Buch versammelt die Ansätze, Architekturen und Erkenntnisse der Projekte. Es überspannt einen breiten Themenbereich, angefangen mit speziellen Fragen der physikalischen Übertragung, des Antennendesigns und der HF-Eingangs-Architekturen für unterschiedliche Frequenzbereiche bis 240 GHz. Darüber hinaus beschreibt das Buch Ansätze für Ultra-Hochgeschwindigkeits-Funksysteme, deren Basisbandverarbeitung, Kodierung sowie mögliche Umsetzungen. Nicht zuletzt wurden auch Fragen des Protokolldesigns behandelt, um eine enge Integration in moderne Computersysteme zu erleichtern. KW - 100 Gbps KW - Wireless KW - Drahtlos KW - DAAB KW - Drahtloses Sensorsystem KW - Hochfrequenztechnik KW - Antenne KW - Terahertzbereich KW - Energieffizienz Y1 - 2020 U6 - https://doi.org/10.26127/BTUOpen-5910 SP - 109 EP - 138 ER - TY - JOUR A1 - Otto, Pascal A1 - Alipoursarbani, Mozhdeh A1 - Torrent, Daniel A1 - Latorre-Pérez, Adriel A1 - Paust, Thomas A1 - Albert, Alfred A1 - Abendroth, Christian T1 - Microbiome characterization after aerobic digestate reactivation of anaerobically digested sewage sludge T1 - Mikrobiomcharakterisierung nach aerober Gärrestreaktivierung von anaerob vergärtem Klärschlamm N2 - A demonstrator plant of a recently patented process for improved sludge degradation has been implemented on a municipal scale. In a 1500 m3 sewage sludge digester, an intermediary stage with aerobic sewage sludge reactivation was implemented. This oxic activation increased the biogas yield by up to 55% with a 25% reduction of the remaining fermentation residue volume. Furthermore, this process allowed an NH4-N removal of over 90%. Additionally, 16S rRNA gene amplicon high-throughput sequencing of the reactivated digestate showed a reduced number of methane-forming archaea compared to the main digester. Multiple ammonium-oxidizing bacteria were detected. This includes multiple genera belonging to the family Chitinophagaceae (the highest values reached 18.8% of the DNA sequences) as well as a small amount of the genus Candidatus nitrosoglobus (<0.3%). In summary, the process described here provides an economically viable method to eliminate nitrogen from sewage sludge while achieving higher biogas yields and fewer potential pathogens in the residuals. N2 - Eine Demonstrationsanlage eines kürzlich patentierten Verfahrens zur verbesserten Schlammzersetzung wurde im kommunalen Maßstab umgesetzt. In einem 1500 m3 Klärschlammfaulbehälter wurde eine Zwischenstufe mit aerober Klärschlammreaktivierung implementiert. Diese oxische Aktivierung steigerte die Biogasausbeute um bis zu 55 % bei einer Reduzierung des verbleibenden Gärrestvolumens um 25 %. Darüber hinaus ermöglichte dieser Prozess eine NH4-N-Entfernung von über 90 %. Weiterhin zeigte die 16S-rRNA-Gen-Amplikon-Hochdurchsatzsequenzierung des reaktivierten Gärrestes eine geringere Anzahl methanbildender Archaeen im Vergleich zum Hauptfermenter. Es wurden mehrere Ammonium-oxidierende Bakterien nachgewiesen. Dazu gehören mehrere Gattungen der Familie Chitinophagaceae (die höchsten Werte erreichten 18,8 % der DNA-Sequenzen) sowie eine kleine Menge der Gattung Candidatus nitrosoglobus (<0,3 %). Zusammenfassend stellt das hier beschriebene Verfahren eine wirtschaftlich sinnvolle Methode dar, um Stickstoff aus Klärschlamm zu eliminieren und gleichzeitig höhere Biogasausbeuten und weniger potenzielle Krankheitserreger in den Reststoffen zu erzielen. KW - Anaerobic digestion KW - Anaerobic microbiomes KW - Aerobic sludge activation KW - 16S rRNA sequencing KW - Water treatment KW - Belebtschlammverfahren KW - Schlammfaulung KW - Mikroorganismus KW - Gärung KW - Biogas KW - Stickstoff-Elimination KW - Anaerobe Vergärung KW - Anaerobe Mikrobiome KW - Aerobe Schlammaktivierung KW - 16S-rRNA-Sequenzierung KW - Wasserversorgung Y1 - 2023 U6 - https://doi.org/10.3390/fermentation9050471 SN - 2311-5637 VL - 9 IS - 5 PB - MDPI CY - Basel ER - TY - JOUR A1 - Murkute, Charuta A1 - Sayeed, Mostafa A1 - Pucha-Cofrep, Franz A1 - Carrillo-Rojas, Galo A1 - Homeier, Jürgen A1 - Limberger, Oliver A1 - Fries, Andreas A1 - Bendix, Jörg A1 - Trachte, Katja T1 - Turbulent energy and carbon fluxes in an Andean montane forest : energy balance and heat storage JF - Forests N2 - High mountain rainforests are vital in the global energy and carbon cycle. Understanding the exchange of energy and carbon plays an important role in reflecting responses to climate change. In this study, an eddy covariance (EC) measurement system installed in the high Andean Mountains of southern Ecuador was used. As EC measurements are affected by heterogeneous topography and the vegetation height, the main objective was to estimate the effect of the sloped terrain and the forest on the turbulent energy and carbon fluxes considering the energy balance closure (EBC) and the heat storage. The results showed that the performance of the EBC was generally good and estimated it to be 79.5%. This could be improved when the heat storage effect was considered. Based on the variability of the residuals in the diel, modifications in the imbalances were highlighted. Particularly, during daytime, the residuals were largest (56.9 W/m2 on average), with a clear overestimation. At nighttime, mean imbalances were rather weak (6.5 W/m2) and mostly positive while strongest underestimations developed in the transition period to morning hours (down to −100 W/m2). With respect to the Monin–Obukhov stability parameter ((z − d)/L) and the friction velocity (u*), it was revealed that the largest overestimations evolved in weak unstable and very stable conditions associated with large u* values. In contrast, underestimation was related to very unstable conditions. The estimated carbon fluxes were independently modelled with a non-linear regression using a light-response relationship and reached a good performance value (R2 = 0.51). All fluxes were additionally examined in the annual course to estimate whether both the energy and carbon fluxes resembled the microclimatological conditions of the study site. This unique study demonstrated that EC measurements provide valuable insights into land-surface–atmosphere interactions and contribute to our understanding of energy and carbon exchanges. Moreover, the flux data provide an important basis to validate coupled atmosphere ecosystem models. KW - Energy balance closure KW - Heat storage KW - Carbon fluxes KW - Eddy covariance KW - Andes Mountains Y1 - 2024 U6 - https://doi.org/10.3390/f15101828 SN - 1999-4907 VL - 15 IS - 10 PB - MDPI CY - Basel ER - TY - JOUR A1 - Manhique, Henrique A1 - Wätzold, Frank T1 - Effects of institutional distrust on value estimates of stated preference surveys in developing countries : a choice experiment on conserving biodiversity within agricultural landscapes in a biodiversity hotspot T1 - Auswirkungen von institutionellem Misstrauen auf Werteinschätzungen bei Erhebungen zur erklärten Präferenz in Entwicklungsländern : ein Auswahlexperiment zur Erhaltung der biologischen Vielfalt in Agrarlandschaften in einem Hotspot der biologischen Vielfalt JF - Q Open N2 - The use of stated preference surveys for the valuation of environmental goods in developing countries has to take into account that there is substantial public distrust towards institutions providing environmental goods under valuation. Thus, high protest responses and low-value estimates may indicate rejection/protest against the institutional setting of the survey, rather than the dislike or low welfare effects of these goods. In this context, we investigate the effects of institutional trust on value estimates by examining the performance of three different institutions government, conservation NGO, and farmers in a case study aimed at eliciting preferences for conserving different types of biodiver- sity within orchards in the Cape Floristic Region a biodiversity hotspot in South Africa threatened by the expansion and intensification of agriculture. We find that institutional trust has an effect on preferences and willingness to pay, with farmers leading to the highest level of trust and value estimates, followed rather closely by a conservation NGO, and, with some distance, by the government with the lowest trust level and value estimates. In terms of preferences for biodiversity conservation, our results show that respondents prefer measures to conserve endangered and endemic species over measures primarily aimed at providing ecosystem services. For future studies in developing countries, we recommend selecting an institutional setting based on the study’s purpose: institutions with high levels of trust should be prioritised for studies aiming to value a good per se, while existing institutions should be prioritised for studies valuing a policy to provide a good within an existing institutional framework. N2 - Bei der Verwendung von Erhebungen über die angegebene Präferenz für die Bewertung von Umweltgütern in Entwicklungsländern muss berücksichtigt werden, dass ein erhebliches öffentliches Misstrauen gegenüber den Institutionen besteht, die die zu bewertenden Umweltgüter bereitstellen. So können hohe Protestantworten und niedrige Wertschätzungen eher auf Ablehnung/Protest gegen die institutionellen Rahmenbedingungen der Umfrage hinweisen als auf die Abneigung oder die geringen Wohlfahrtseffekte dieser Güter. In diesem Zusammenhang untersuchen wir die Auswirkungen von institutionellem Vertrauen auf Wertschätzungen, indem wir die Leistung von drei verschiedenen Institutionen Regierung, Naturschutz-NGOs und Landwirten in einer Fallstudie untersuchen, die darauf abzielt, Präferenzen für den Erhalt verschiedener Arten von Biodiversität in Obstplantagen in der floristischen Kapregion zu ermitteln. Einem Hotspot der Biodiversität in Südafrika, der durch die Expansion und Intensivierung der Landwirtschaft bedroht ist. Wir stellen fest, dass sich institutionelles Vertrauen auf die Präferenzen und die Zahlungsbereitschaft auswirkt, wobei Landwirte das höchste Vertrauensniveau und die höchsten Werteinschätzungen aufweisen, dicht gefolgt von einer Naturschutz-NGO und mit einigem Abstand von der Regierung mit dem niedrigsten Vertrauensniveau und den niedrigsten Werteinschätzungen. Was die Präferenzen für die Erhaltung der biologischen Vielfalt angeht, so zeigen unsere Ergebnisse, dass die Befragten Maßnahmen zur Erhaltung gefährdeter und endemischer Arten gegenüber Maßnahmen bevorzugen, die in erster Linie auf die Bereitstellung von Ökosystemleistungen abzielen. Für künftige Studien in Entwicklungsländern empfehlen wir die Auswahl eines institutionellen Rahmens, der sich nach dem Zweck der Studie richtet: Institutionen mit einem hohen Vertrauensniveau sollten bei Studien, die auf die Bewertung eines Gutes an sich abzielen, bevorzugt werden, während bestehende Institutionen bei Studien, die eine Politik zur Bereitstellung eines Gutes innerhalb eines bestehenden institutionellen Rahmens bewerten, bevorzugt werden sollten. KW - Drivers of institutional distrust KW - Economics KW - Ecosystem services KW - Endangered species KW - Payment vehicle KW - Faktoren für institutionelles Misstrauen KW - Wirtschaft KW - Ökosystemdienstleistungen KW - Bedrohte Arten KW - Zahlungsmittel KW - Südafrika KW - Bekundete Präferenz KW - Umweltschutz KW - Regierung KW - Nichtstaatliche Organisation KW - Landwirt KW - Misstrauen Y1 - 2024 U6 - https://doi.org/10.1093/qopen/qoae014 SN - 2633-9048 VL - 4 IS - 1 PB - Oxford University Press CY - Oxford ER - TY - JOUR A1 - Menares, Esteban A1 - Saíz, Hugo A1 - Schenk, Noëlle A1 - Riva, Enrique G. de la A1 - Kraus, Jochen A1 - Birkhofer, Klaus T1 - Co-occrrence patterns do not predict mutualistic interactions between plant and butterfly species JF - Ecology and Evolution N2 - Biotic interactions are crucial for determining the structure and dynamics of communities; however, direct measurement of these interactions can be challenging in terms of time and resources, especially when numerous species are involved. Inferring species interactions from species co-occurrence patterns is increasingly being used; however, recent studies have highlighted some limitations. To our knowledge, no attempt has been made to test the accuracy of the existing methods for detecting mutualistic interactions in terrestrial ecosystems. In this study, we compiled two literature-based, long-term datasets of interactions between butterflies and herbaceous plant species in two regions of Germany and compared them with observational abundance and presence/absence data collected within a year in the same regions. We tested how well the species associations generated by three different co-occurrence analysis methods matched those of empirically measured mutualistic associations using sensitivity and specificity analyses and compared the strength of associations. We also checked whether flower abundance data (instead of plant abundance data) increased the accuracy of the co-occurrence models and validated our results using empirical flower visitation data. The results revealed that, although all methods exhibited low sensitivity, our implementation of the Relative Interaction Intensity index with pairwise null models performed the best, followed by the probabilistic method and Spearman's rank correlation method. However, empirical data showed a significant number of interactions that were not detected using co-occurrence methods. Incorporating flower abundance data did not improve sensitivity but enhanced specificity in one region. Further analysis demonstrated incongruence between the predicted co-occurrence associations and actual interaction strengths, with many pairs exhibiting high interaction strength but low co-occurrence or vice versa. These findings underscore the complexity of ecological dynamics and highlight the limitations of current co-occurrence methods for accurately capturing species interactions. KW - Biodiversity exploratories KW - Co-occurrence analysis KW - Flower visitations KW - Mutualistic interactions KW - Species associations Y1 - 2024 U6 - https://doi.org/10.1002/ece3.70498 SN - 2045-7758 VL - 14 IS - 11 PB - Wiley CY - London ER - TY - JOUR A1 - Gnegel, Fabian A1 - Schaudt, Stefan A1 - Clausen, Uwe A1 - Fügenschuh, Armin T1 - A graph-refinement algorithm to minimize squared delivery delays using parcel robots JF - Mathematics N2 - In recent years, parcel volumes have reached record highs, prompting the logistics industry to explore innovative solutions to meet growing demand. In densely populated areas, delivery robots offer a promising alternative to traditional truck-based delivery systems. These autonomous electric robots operate on sidewalks and deliver time-sensitive goods, such as express parcels, medicine and meals. However, their limited cargo capacity and battery life require a return to a depot after each delivery. This challenge can be modeled as an electric vehicle-routing problem with soft time windows and single-unit capacity constraints. The objective is to serve all customers while minimizing the quadratic sum of delivery delays and ensuring each vehicle operates within its battery limitations. To address this problem, we propose a mixed-integer quadratic programming model and introduce an enhanced formulation using a layered graph structure. For this layered graph, we present two solution approaches based on relaxations that reduce the number of nodes and arcs compared to the expanded formulation. The first approach, Iterative Refinement, solves the current relaxation to optimality and refines the graph when the solution is infeasible for the expanded formulation. This process continues until a proven optimal solution is obtained. The second approach, Branch and Refine, integrates graph refinement into a branch-and-bound framework, eliminating the need for restarts. Computational experiments on modified Solomon instances demonstrate the effectiveness of our solution approaches, with Branch and Refine consistently outperforming Iterative Refinement across all tested parameter configurations. KW - Integer programming KW - Layered graph refinement KW - Delivery robots KW - Electric vehicle-routing problem KW - Partial recharging Y1 - 2024 U6 - https://doi.org/10.3390/math12203201 SN - 2227-7390 VL - 12 PB - MDPI CY - Basel ER - TY - JOUR A1 - Liedtke, Victoria A1 - Weiss, Romano A1 - Skifov, Anastasia A1 - Rödiger, Stefan A1 - Schenk, Lysann T1 - Fully automated viability and toxicity screening : a reliable all-in-one attempt T1 - Vollautomatisches Vitalitäts- und Toxizitätsscreening : ein zuverlässiger all-in-one Ansatz JF - Cancer Medicine N2 - The CRISPR/Cas9 technology is nowadays a common tool for genome editing to achieve new insights into, e.g., diagnostics and therapeutics in cancer and genetic disorders. Cell proliferation and anti-cancer drug response studies are widely used to evaluate the impact of editing. However, these assays are often time-consuming, expensive and reproducibility is an issue. To overcome this, we developed a fast and cheap assay that combines a fully automated multispectral fluorescence microscopy platform with a nuclei staining and open source software analysis. Here, we generated different LEDGF/p75 model cell lines to validate the effect on proliferation and chemosensitivity. Therefore, a fast protocol for an optimized all-in-one attempt for cytotoxicity screenings and proliferation analysis of adherent cells in a 96-well plate format was established using differential staining with two fluorescent dyes (Hoechst 33342 and propidium iodide) for live/dead cell discrimination. Subsequently, an automated cell nuclei count and analysis was performed using bioimage informatics. With the new established assay technology, up to 50000 cells/well can be detected and analyzed in a 96-well plate, resulting in a fast and accurate verification of viability and proliferation with consistency of 98 % compared to manual counting. Our screening revealed that LEDGF depletion using CRISPR/Cas9 showed a diminished proliferation and chemosensitivity independent of cell line origin. Moreover, LEDGF depletion caused a significant increase in 𝛾H2AX foci, indicating a substantial increase in DNA double strand breaks. LEDGF/p75 overexpression enhanced proliferation and chemoresistance underlining the role of LEDGF in DNA damage response. Independent of cancer cell type, LEDGF/p75 is a central player in DNA damage repair and is implicated in chemoresistance. Moreover, our automated fluorescence biosensor technology allowed fast and reliable data acquisition without any fixation or additional washing steps. Additionally, data analysis was implemented using modular open source software that can be adapted as needed. N2 - Die CRISPR/Cas9-Technologie ist heute ein gängiges Werkzeug für die Genom-Editierung, um neue Erkenntnisse für z. B. die Diagnostik und Therapie von Krebserkrankungen und genetischen Störungen zu gewinnen Studien zur Zellproliferation und zum Ansprechen auf Krebsmedikamente werden häufig eingesetzt, um die Auswirkungen des Editierens zu bewerten. Diese Tests sind jedoch oft zeitaufwändig, teuer und in der Reproduzierbarkeit ungenau. Um dies zu überwinden, haben wir einen schnellen und kostengünstigen Test entwickelt, der eine vollautomatische multispektrale Fluoreszenzmikroskopie-Plattform mit einer Kernfärbung und einer Open-Source-Software-Analyse kombiniert.Wir haben verschiedene LEDGF/p75-Modellzelllinien generiert, um die Auswirkungen auf die Proliferation und Chemosensitivität zu validieren. Daher wurde ein schnelles Protokoll für einen optimierten All-in-One-Ansatz für Zytotoxizitäts-Screenings und Proliferationsanalysen von adhärenten Zellen in einem 96-Well-Plattenformat erstellt, bei dem eine differenzierte Färbung mit zwei Fluoreszenzfarbstoffen (Hoechst 33342 und Propidiumjodid) zur Unterscheidung von lebenden und toten Zellen verwendet wurde. Anschließend wurde eine automatische Zählung und Analyse der Zellkerne mit Hilfe der Bioimage-Informatik durchgeführt. Mit der neuen etablierten Assay-Technologie können bis zu 50.000 Zellen pro Well in einer 96-Well-Platte nachgewiesen und analysiert werden, was eine schnelle und genaue Überprüfung der Lebensfähigkeit und Proliferation mit einer Übereinstimmung von 98 % im Vergleich zur manuellen Zählung ermöglicht. Unser Screening ergab, dass die Deletion von LEDGF mit CRISPR/Cas9 eine verringerte Proliferation und Chemosensitivität, unabhängig von der Herkunft der Zelllinie, zur Folge hatte. Darüber hinaus führte die Deletion von LEDGF zu einer signifikanten Zunahme von 𝛾H2AX-Foci, was auf eine erhebliche Zunahme von DNA-Doppelstrangbrüchen hinweist. Die Überexpression von LEDGF/p75 erhöhte die Proliferation und Chemoresistenz, was die Rolle von LEDGF bei der DNA-Schadensreaktion unterstreicht. Unabhängig vom Krebszelltyp ist LEDGF/p75 ein zentraler Akteur bei der DNA-Schadensreparatur und ist an der Chemoresistenz beteiligt. Darüber hinaus ermöglichte unsere automatisierte Fluoreszenz-Biosensor-Technologie eine schnelle und zuverlässige Datenerfassung ohne Fixierung oder zusätzliche Waschschritte. Darüber hinaus wurde die Datenanalyse mit einer modularen Open-Source-Software durchgeführt, die je nach Bedarf angepasst werden kann. KW - Automated system KW - CRISPR/Cas9 KW - Bioimage informatics KW - Viability KW - Cytotoxicity KW - Automatisiertes System KW - Vitalität KW - Bioimage-Informatik KW - Zytotoxizität KW - Multiparameteranalyse KW - Fluoreszenzmikroskopie KW - Cytotoxizität KW - Proliferation KW - Vitalität Y1 - 2023 U6 - https://doi.org/10.1002/cam4.7392 SN - 2045-7634 VL - 13 IS - 12 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Ahmed, Rezwan A1 - Zafor, Md. Abu A1 - Trachte, Katja T1 - Land-use and land-cover changes in Cottbus city and Spree-Neisse district, Germany, in the last two decades : a study using remote sensing data and Google Earth Engine JF - Remote Sensing N2 - Regular detection of land-use and land-cover (LULC) changes with high accuracy is necessary for natural resources management and sustainable urban planning. The produced LULC maps from Google Earth Engine (GEE) also illustrate the transformation of the LULC for the respective landscape over time. The selected study area, Cottbus City and the Spree-Neisse district in northeastern Germany, has undergone significant development over the past decades due to various factors, including urbanization and industrialization; also, the landscape has been converted in some areas for post-mining activities. Detection of LULC changes that have taken place over the last few decades thus plays a vital role in quantifying the impact of these factors while improving the knowledge of these developments and supporting the city planners or urban management officials before implementing further long-term development initiatives for the future. Therefore, the study aims to (i) detect LULC changes for the time slices 2002 and 2022, testing machine learning (ML) algorithms in supervised and unsupervised classification for Landsat satellite imageries, and (ii) validate the newly produced LULC maps with the available regional database (RDB) from the federal and state statistical offices, Germany, and the DynamicWorld (DW) near real-time 10 m global LULC data set powered by artificial intelligence (AI). The results of the Random Forest (RF) and the Smilecart classifiers of supervised classification using Landsat 9 OLI-2/TIRS-2 in 2022 demonstrated a validation accuracy of 88% for both, with Kappa Index (KI) of 83% and 84%, respectively. Moreover, the Training Overall Accuracy (TOA) was 100% for both years. The wekaKMeans cluster of the unsupervised classification also illustrated a similar transformation pattern in the LULC maps. Overall, the produced LULC maps offered an improved representation of the selected region’s various land-cover classes (i.e., vegetation, waterbodies, built areas, and bare ground) in the last two decades (2022 to 2022). KW - LULC KW - Machine learning KW - Landsat KW - Google Earth Engine KW - Landnutzung KW - Bodenbedeckung KW - Landsat KW - Google Earth KW - Maschinelles Lernen Y1 - 2024 U6 - https://doi.org/10.3390/rs16152773 SN - 2072-4292 VL - 16 IS - 15 PB - MDPI CY - Basel ER - TY - JOUR A1 - Khan, Muhammad Moman A1 - Mushtaq, Muhammad Ahmed A1 - Abbas, Nayyar A1 - Fatima, Fariha A1 - Gibbon, Marjorie J. A1 - Schierack, Peter A1 - Mohsin, Mashkoor T1 - Occurrence, antimicrobial resistance and genomic features of Klebsiella pneumoniae from broiler chicken in Faisalabad, Pakistan JF - Frontiers in Veterinary Science N2 - The dissemination of antimicrobial resistance (AMR) in critical priority pathogens is a significant threat. Non-clinical reservoirs of AMR, such as agriculture and food production facilities, may contribute to the transmission of clinically relevant pathogens such as multidrug-resistant (MDR) Klebsiella pneumoniae. There is currently very limited knowledge regarding the population structure and genomic diversity of K. pneumoniae in poultry production in Pakistan. We explored healthy broilers in a commercial farm from Faisalabad, Pakistan, and identified six K. pneumoniae strains from 100 broiler birds. We characterized the strains, determining clonality, virulence and antimicrobial resistance genes using next generation sequencing. The evaluation of antimicrobial susceptibility revealed that all the strains were MDR. Genomic analysis showed that 3/6 strains belonged to ST152, harbouring acquired resistance aminoglycosides [aadA2, aph(4′)-Ia], β-lactams (blaSHV-187, blaLAP2), fosfomycin (fosA6), tetracycline (tetA), trimethoprim (dfrA12), quinolone (qnrS1), sulphonamides (sul2) and phenicol (floR). All the strains harboured the efflux pump genes oqxA, oqxB, emrR, kpnG, kpnH, kpnF, baeR, mtdB and mtdC. All six strains encoded identical virulence profiles possessing six genes, i.e., ureA, iutA, entB, allS, fimH and mrkD. Phylogenomic analysis of the dominant sequence type (ST152) present in our dataset with publicly available genomes showed that the isolates clustered to strains mainly from human sources and could pose a potential threat to food safety and public health. The combination of these findings with antimicrobial use data would allow a better understanding of the selective pressures that may be driving the spread of AMR. This is the first report of MDR K. pneumoniae isolated from broiler hens in Pakistan, and the finding suggests that routine surveillance of WHO critical priority pathogens in such settings would be beneficial to the development of effective control strategies to reduce AMR. KW - Antimicrobial resistance KW - Poultry KW - Genomics KW - K. pneumoniae KW - Sequence type Y1 - 2024 U6 - https://doi.org/10.3389/fvets.2024.1433124 SN - 2297-1769 VL - 11 PB - Frontiers CY - Lausanne ER - TY - JOUR A1 - Frimpong, Bernard Fosu A1 - Molkenthin, Frank A1 - Koranteng, Addo T1 - Analysis of temperature variability utilising Mann–Kendall and Sen’s slope estimator tests in the Accra and Kumasi metropolises in Ghana T1 - Untersuchung der Temperaturvarabilität mit Mann–Kendall-Trendtest und Sen-Slope Schätzer in den Städten Accra und Kumasi in Ghana N2 - Temperature variability may have direct and indirect impacts on the environments of the Accra and Kumasi Metropolises in Ghana. This study analysed temperature and trends in temperature in both cities using in-situ measurements from one meteorological station in both cities from 1986 to 2015. The temperature indices were computed using the RClimdex package from the Expert Team on Climate Change Detection Monitoring Indices (ETCCDMI). The temperature time series was pre-whitened before the Mann–Kendall trend and Sen’s slope estimator analysis were applied. Initial analysis revealed minimal variation in temperature in both cities. The results from the analysed temperature indices revealed an increase in warm days and a general rise in the minimum temperature compared to maximum temperatures. Mann Kendall and Sen’s slope revealed significant trends in the annual and seasonal (dry and wet seasons) in minimum temperature in both cities. These might lead to an increased rate of heat-stressed diseases and an overall rise in urban warming in both cities. The analysis of temperature, indices and trends provided comprehensive insights into the temperature of Accra and Kumasi. The results highlight the essence of evaluating temperature indices and trends in light of Climate Change concerns. It is recommended that urban green and blue spaces should be incorporated into land use plans as these policy directions can aid regulate the temperature in both cities. N2 - Temperaturschwankungen können direkte und indirekte Auswirkungen auf die Umwelt in den Metropolen Accra und Kumasi in Ghana haben. In dieser Studie wurden die Temperatur und die Temperaturtrends in beiden Städten anhand von Messungen jeweils einer meteorologischen Station in beiden Städten von 1986 bis 2015 analysiert. Die Temperaturindizes wurden mit dem RClimdex-Paket des Expert Team on Climate Change Detection Monitoring Indices (ETCCDMI) berechnet. Die gemessenen Temperaturzeitreihen wurde für die Analyse mit Mann-Kendall-Trend und Sen-Slope Schätzer auf- und vorbereitet. Eine erste Analyse ergab minimale Temperaturschwankungen in beiden Städten. Die Ergebnisse der analysierten Temperaturindizes zeigten eine Zunahme der warmen Tage und einen allgemeinen Anstieg der Minimaltemperatur im Vergleich zu den Maximaltemperaturen. Beide Methoden zeigten signifikante Trends im jährlichen und saisonalen (Trocken- und Regenzeit) Verlauf der Mindesttemperatur in beiden Städten. Diese Trends könnten zu einer Erhöhung von hitzebedingten gesundheitlichen Problemen und einer allgemeinen Erwärmung in beiden Städten führen. Die Analyse von Temperaturen, Indizes und Trends führte zu einem erweiterten Verständnis der Temperaturverläufe in Accra und Kumasi. Die Ergebnisse unterstreichen die Bedeutung der Bewertung von Temperaturindizes und -trends im Hinblick auf den Klimawandel. Es wird empfohlen, städtische Grün- und Wasserflächen in die Flächennutzungspläne mit aufzunehmen, damit diese strategischen Planungs- und Regelwerke genutzt werden können, die die Temperatur in beiden Städten positiv beeinflussen zu können. KW - Temperature variability KW - Mann-Kendall test KW - Sen's slope estimator KW - Accra KW - Kumasi KW - Temperaturvarabilität KW - Sen-Slope Schätzer KW - Accra KW - Kumasi KW - Temperatur KW - Schwankung Y1 - 2022 U6 - https://doi.org/10.1186/s40068-022-00269-1 ER - TY - JOUR A1 - Kayatz, Benjamin A1 - Baroni, Gabriele A1 - Hillier, Jon A1 - Wattenbach, Martin T1 - Supporting decision-making in agricultural water management under data scarcity using global datasets : chances, limits and potential improvements T1 - Unterstützung der Entscheidungsfindung in der landwirtschaftlichen Wasserbewirtschaftung bei Datenknappheit unter Verwendung globaler Datensätze : Chancen, Grenzen und mögliche Verbesserungen JF - Agricultural Water Management N2 - Assessing alternative agricultural water management strategies requires long-term field trials or vast data collection for model calibration and simulation. This work aims to assess whether an uncalibrated agro-hydrological model using global input datasets for climate, soil and crop information can serve as a decision support tool for crop water management under data scarcity. This study employs the Cool Farm Tool Water (CFTW) at eight eddy covariance sites of the FLUXNET2015 dataset. CFTW is tested using global (CFTWglobal) and local (CFTWlocal) input datasets under current and alternative management scenarios. Results show that the use of global datasets for estimating daily evapotranspiration had little effect on the median Root Mean Square Error (RMSE) (CFTWglobal: 1.70 mm, CFTWlocal: 1.79 mm), while, however, the median model bias is much greater (CFTWglobal: - 18.6%, CFTWlocal: - 4.3%). Furthermore, the periods of water stress were little affected by the use of local or global data (median accuracy: 0.84), whereas the use of global data inputs led to a significant overestimation of irrigation water requirements (median difference: 110 mm). The model performance improves predominantly through the use of more representative local precipitation data, followed by local reference evapotranspiration and soil for some European growing seasons. We identify model outputs that can support decision-making when relying on global data, such as periods of water stress and the daily dynamics of water use. However, our findings also emphasize the difficulty of overcoming data scarcity in decision-making in agricultural water management. Furthermore, we provide recommendations for enhancing model performance and thus may increase the accessibility of reliable decision support tools in the future. N2 - Die Bewertung alternativer Wasserbewirtschaftungsstrategien in der Landwirtschaft erfordert langfristige Feldversuche oder umfangreiche Datenerhebungen Datenerhebung für die Modellkalibrierung und Simulation. Ziel dieser Arbeit ist es, zu beurteilen, ob ein unkalibriertes agrarhydrologisches Modell, das globale Eingabedatensätze für Klima-, Boden- und Kulturpflanzeninformationen als Entscheidungshilfe für das in der Landwirtschaft bei Datenknappheit Knappheit dienen kann. Die Ergebnisse zeigen, dass die Verwendung globaler Datensätze für die Schätzung der täglichen Evapotranspiration kaum Auswirkungen auf den mittleren quadratischen Fehler (RMSE) hat (CFTWglobal: 1,70 mm, CFTWlocal: 1,79 mm), während jedoch die die mediane Modellverzerrung jedoch viel größer ist (CFTWglobal: - 18,6 %, CFTWlocal: - 4,3 %). Außerdem wurden die Perioden des Außerdem wurden die Perioden des Wasserstresses durch die Verwendung lokaler oder globaler Daten nur wenig beeinflusst (mediane Genauigkeit: 0,84), während die Verwendung globaler globalen Dateneingaben zu einer signifikanten Überschätzung des Bewässerungswasserbedarfs führte (medianer Unterschied: 110 mm). Die Leistung des Modells verbessert sich in erster Linie durch die Verwendung repräsentativerer lokaler Niederschlagsdaten Daten, gefolgt von lokalen Referenzwerten für Evapotranspiration und Boden für einige europäische Wachstumsperioden. Wir ermitteln Modelloutputs, die die Entscheidungsfindung unterstützen können, wenn man sich auf globale Daten stützt, z. B. Perioden von Wasserstress und die tägliche Dynamik der Wassernutzung. Unsere Ergebnisse verdeutlichen jedoch auch die Schwierigkeit, die Datenknappheit bei der Entscheidungsfindung in der landwirtschaftlichen Wasserwirtschaft. Darüber hinaus geben wir Empfehlungen Empfehlungen zur Verbesserung der Modellleistung und können so die Verfügbarkeit von zuverlässigen Entscheidungshilfen in der Zukunft verbessern. KW - Crop water use KW - Crop water requirement KW - Evapotranspiration KW - Irrigation KW - Cool farm tool KW - Wasserverbrauch der Kulturpflanzen KW - Wasserbedarf der Kulturpflanzen KW - Evapotranspiration KW - Bewässerung KW - FAO56 KW - Bewässerungswirtschaft KW - Mathematisches Modell KW - Bewässerung KW - Evapotranspiration KW - Wasserbedarf KW - Kulturpflanzen Y1 - 2023 U6 - https://doi.org/10.1016/j.agwat.2024.108803 SN - 0378-3774 VL - 296 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Leuner, Bruna A1 - Hirschl, Bernd T1 - Biomass and bioenergy perspectives of a coal region : status quo, potential and scenarios in Lusatia T1 - Biomasse- und Bioenergieperspektiven einer Kohleregion : Status quo, Potenzial und Szenarien in der Lausitz JF - Frontiers in Energy Research N2 - Coal has been one of the main fuels used in Europe. Its decreasing role due to the ongoing transformation of the energy system will create significant socio-economic challenges. The switch into renewable energy systems could be an alternative to maintain jobs and economic activities within the affected regions. Biomass use and bioenergy can play an important role in the energy transition. Instead of energy crops, forest and agricultural residues should be used as biogenic energy sources in the future to avoid impacts on land use and food security. The main objective of this article is to investigate the biomass potential of a coal region and to provide scenarios for the future development of bioenergy production. Due to the changing framework conditions and, as a result, the different biomass focuses, previous bioenergy potential estimates must be reviewed. The methods for determining the potential of biomass for energy production was used for Lusatia (in German: Lausitz), the second largest coal region in Germany. These methods can also be applied in other regions. As a first step, the regional status quo assessment of cultivated areas and yields had decisive relevance for calculating biomass potential ranges. In a second step, the current bioenergy facilities in the region were identified, with a focus on power and heat production. The third step was the estimation of future regional bioenergy use. Therefore, the regional potential was gathered with the generally supra-regional framework conditions. For this purpose, national scenario studies were used, which contain the relevant target values and framework conditions. Two scenarios were developed for future bioenergy estimations: a conservative path based on the current policies and a progressive path, derived from the goal of climate neutrality by 2045. The results show a qualitative comparison among both scenarios and the previously determined potential ranges. Bioenergy can probably contribute to achieving climate neutrality with an increase in wood-fired systems, while agricultural bioenergy potential is likely to decline. In the discussion section, however, the uncertainty of these results is pointed out, as future use of bioenergy will be heavily influenced by the regulatory framework, competition with material use and the influences of climate change. N2 - Kohle war einer der wichtigsten Energieträger in Europa. Ihre abnehmende Bedeutung aufgrund der laufenden Umgestaltung des Energiesystems wird erhebliche sozioökonomische Herausforderungen mit sich bringen. Die Umstellung auf erneuerbare Energiesysteme könnte eine Alternative sein, um Arbeitsplätze und wirtschaftliche Aktivitäten in den betroffenen Regionen zu erhalten. Die Nutzung von Biomasse und Bioenergie kann eine wichtige Rolle bei der Energiewende spielen. Anstelle von Energiepflanzen sollten in Zukunft forst- und landwirtschaftliche Reststoffe als biogene Energieträger genutzt werden, um Auswirkungen auf die Landnutzung und die Ernährungssicherheit zu vermeiden. Das Hauptziel dieses Artikels ist es, das Biomassepotenzial einer Kohleregion zu untersuchen und Szenarien für die zukünftige Entwicklung der Bioenergieproduktion zu erstellen. Aufgrund der sich ändernden Rahmenbedingungen und der daraus resultierenden unterschiedlichen Biomasseschwerpunkte müssen bisherige Bioenergiepotenzialabschätzungen überprüft werden. Die Methoden zur Ermittlung des Potenzials von Biomasse zur Energieerzeugung wurden für die Lausitz, das zweitgrößte Kohlerevier Deutschlands, angewendet. Diese Methoden können auch in anderen Regionen angewendet werden. KW - Regional biomass potential KW - Bioenergy scenarios KW - Coal region KW - Regional energy transition KW - Lusatia KW - Regionales Biomassepotenzial KW - Bioenergieszenarien KW - Kohleregion KW - Regionale Energiewende KW - Lausitz Y1 - 2024 U6 - https://doi.org/10.3389/fenrg.2023.1275733 SN - 2296-598X VL - 11 PB - Frontiers CY - Lausanne ER - TY - JOUR A1 - König, Paul A1 - Sharma, Dikshant A1 - Konda, Karunakar Reddy A1 - Xie, Tianxiao A1 - Höschler, Klaus T1 - Comprehensive review on cooling of permanent magnet synchronous motors and their qualitative assessment for aerospace applications T1 - Umfassender Überblick über die Kühlung von Permanentmagnet-Synchronmotoren und ihre qualitative Bewertung für Luft- und Raumfahrtanwendungen N2 - The permanent magnet synchronous motor (PMSM) can be a suitable candidate for electrified propulsion in aviation. Despite the very high efficiency, heat dissipation during operation leads to performance limitations. Elevated temperatures in the electrical insulations and the magnets pose a potential safety risk that must be reduced by selective cooling. A comprehensive review is conducted to capture current research interests in cooling methods in PMSM. Cooling methods are described according to their heat transfer mechanism, grouped, and assigned to the components within the motor. Key findings of the literature reviewed are described in the context of PMSM cooling. Information on cooling media and potential combinations of cooling methods in components is gathered. Assessment parameters such as safety, weight, effectiveness, integrability, complexity and cost are defined to enable a subsequent qualitative analysis for six selected cooling methods. A point-weighted evaluation approach, according to VDI 2225, was applied to identify the most promising cooling approach for successful implementation in aviation. N2 - Der Permanentmagnet-Synchronmotor (PMSM) ist ein geeigneter Kandidat für elektrifizierte Antriebe in der Luftfahrt. Trotz des sehr hohen Wirkungsgrades führt die Abwärme während des Betriebs zu Leistungseinschränkungen. Erhöhte Temperaturen in den elektrischen Isolierungen und den Permanentmagneten stellen ein potenzielles Sicherheitsrisiko dar, das durch gezielte Kühlung reduziert werden muss. Ein umfassender Überblick über die aktuellen Forschungsaktivitäten im Bereich der Kühlungsmethoden für PMSM wird vorgestellt. Die Kühlungsmethoden werden nach ihrem Wärmeübertragungsmechanismus beschrieben, gruppiert und den Komponenten innerhalb des Motors zugeordnet. Die wichtigsten Ergebnisse der gesichteten Literatur werden im Zusammenhang mit der PMSM-Kühlung beschrieben. Es werden Informationen über Kühlmedien und mögliche Kombinationen von Kühlmethoden in Komponenten gesammelt. Bewertungsparameter wie Sicherheit, Gewicht, Effektivität, Integrierbarkeit, Komplexität und Kosten werden definiert, um anschließend eine qualitative Analyse für sechs ausgewählte Kühlmethoden zu ermöglichen. Ein punktgewichteter Bewertungsansatz nach VDI 2225 wurde verwendet, um den vielversprechendsten Kühlungsansatz für eine erfolgreiche Umsetzung in der Luftfahrt zu identifizieren. KW - Electrical machines KW - Electric aviation KW - Motor cooling KW - PMSM KW - Thermal management KW - Elektrische Luftfahrt KW - Elektrische Maschinen KW - Motorkühlung KW - Wärmemanagement KW - Luftfahrt KW - Raumfahrt KW - Elektroantrieb KW - Dauermagneterregter Synchronmotor KW - Kühlung Y1 - 2023 U6 - https://doi.org/10.3390/en16227524 ER - TY - JOUR A1 - Bolton, Sharon C. A1 - Laaser, Knut T1 - The moral economy of solidarity : a longitudinal study of special needs teachers N2 - Based on a longitudinal study of a Pupil Referral Unit (PRU) in England for children excluded from mainstream schools and utilising a moral economy lens, this article explores how solidarity is created and maintained in a very particular community of teachers and learning support assistants (LSAs). A moral economy approach highlights the centrality of people’s moral norms and values for understanding the multi-layered dimensions of solidarity in organisations and how it changes in the context of transformations in the labour process. The article illustrates how teachers and LSAs rely on mutuality, underpinned by moral norms of justice, and values of care, dignity and recognition, to cope with physically and emotionally demanding work that is under-resourced and undervalued. The analysis reveals that solidarity is not only against unjust workplace regimes, but also for connectivity and a humanised labour process. KW - England KW - Moral economy KW - Inequality KW - Pupil Referral Unit KW - Schools KW - Solidarity KW - Sonderschule KW - Lehrerkollegium KW - Solidarität KW - Moral KW - Norm Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:co1-opus4-52124 SN - 0950-0170 SN - 1469-8722 PB - SAGE Publications CY - London, England ER - TY - JOUR A1 - Leuner, Bruna A1 - Hirschl, Bernd A1 - Bezerra, Pedro Henrique A1 - Pedrosa Quintino, Wellington A1 - Bezerra, Roberta A1 - Cavalcante Silva, Rodolfo T1 - Indigenous bioeconomy in Brazil : how to determine the local biomass potential in indigenous territories JF - Journal of Integrative Environmental Sciences N2 - The increased expansion of agricultural areas in central Brazil has been cited as a contributing factor to deforestation, soil degradation and water pollution. The impact of this expansion extends beyond the boundaries of the territory of the Xavante indigenous group. These protected areas have experienced a marked decline in available food resources and an unreliable energy supply. The term “indigenous bioeconomy” represents a holistic approach that aims to enhance the well-being of indigenous communities. It recognises indigenous knowledge and promotes the sustainable use of resources. The indigenous bioeconomy contributes to climate protection, by avoiding deforestation and replacing the use of fossil fuels in isolated areas with biogenic alternatives. This paper analyses the local biomass potential of a community within the Pimentel Barbosa Indigenous Territory of the Xavante ethnic group. Participatory research was employed to gain an in-depth understanding of the customary Xavante practices. The theoretical biomass potential was estimated at around 2700 tonnes per year (t/a), which is defined as the total amount of selected biomass types available in the investigated area. Local practical biomass potential considers the per capita consumption of this biomass by the indigenous population. Furthermore, the authors quantified the unused biomass potential, representing biomass that could be used for various purposes including food, medicine and energy. Biomass residues have an untapped potential of around 180 t/a. The paper outlines possible utilisation scenarios for these residues and considers the challenges associated with food and energy security in indigenous territories. KW - Indigenous bioeconomy KW - Local biomass potential KW - Cerrado biome KW - Xavante Y1 - 2025 U6 - https://doi.org/10.1080/1943815X.2025.2566009 SN - 1943-8168 VL - 22 IS - 1 PB - Taylor & Francis CY - London ER - TY - JOUR A1 - Kansok-Dusche, Julia A1 - Wettstein, Alexander A1 - Fischer, Saskia A1 - Wachs, Sebastian A1 - Bilz, Ludwig T1 - Associations between teachers’ beliefs and their perception of hate speech in school : a study in Germany and Switzerland JF - Frontiers in Education N2 - Hate speech is a global issue that is also prevalent among adolescents and requires an educational response. Teachers handle hate speech as part of their professional role. To date, we know little about their beliefs in relation to the early stages of their interventional actions, specifically to their perception of hate speech in school. Thus, this study examined associations between teachers' social dominance orientation, their pluralist attitude, and their hate speech perception in school. A sample of 471 secondary school teachers from 38 schools (Germany: n = 251; Switzerland: n = 220) participated in a self-report survey from December 2020 to April 2021 (MAge = 42.8 years; 57.7% females; 21.0% with migration status). Data from a total of 3,560 students from grades 7 to 9 (Germany: n = 1,841; Switzerland: n = 1,719)were matched with teachers' data to control for students' hate speech perception in school.Fixed effects multilevel regressions were run, including covariates (teachers' age, gender, migration status, students' hate speech perception), teachers' social dominance orientation, pluralist attitude, and their hate speech perception in school. Teachers perceived a higher frequency of offline hate speech than online hate speech. Contrary to the hypotheses, social dominance orientation was positively associated with offline and online hate speech perception. As predicted, teachers' pluralist attitude was positively linked to their off-and online hate speech perception. Further research must now clarify how the investigated beliefs and attitudes and teachers' hate speech perception in school relate to other aspects of their professional competence. KW - Hate speech perception KW - Teachers KW - School KW - Beliefs KW - Social dominance orientation KW - Hassrede KW - Integrität KW - Lehrer KW - Lehrerin KW - Studie KW - Intervention KW - Überlegenheit Y1 - 2024 U6 - https://doi.org/10.3389/feduc.2024.1432013 SN - 2504-284X VL - 9 IS - Sec. Teacher Education PB - Frontiers CY - Lausanne ER - TY - JOUR A1 - Obrosov, Aleksei A1 - Fallah, Mamoun A1 - Hezil, Naouel A1 - Bouras, Dikra A1 - Bouchareb, Nabila A1 - Perez Larios, Alejandro A1 - El-Hiti, Gamal A. A1 - Weiß, Sabine T1 - Investigating the effect of Zr content on electrochemical and tribological properties of newly developed near β-type Ti-alloys (Ti–25Nb-xZr) for biomedical applications T1 - Untersuchung der Auswirkung des Zr-Gehalts auf die elektrochemischen und tribologischen Eigenschaften neu entwickelter β-naher Ti-Legierungen (Ti-25Nb-xZr) für biomedizinische Anwendungen JF - Journal of Science: Advanced Materials and Devices N2 - In order to create alloys with exceptional properties for orthopedic uses, this study focuses on the impact of zirconium (Zr) content on the structural, electrochemical, and tribological qualities of nanostructured Ti–25NbxZr [x = 5, 10, 15, 20, 25, and 30 atomic (at.) %] alloys. The structural evolution was investigated using XRD and SEM techniques. The mechanical characteristics of the produced alloys, including Vickers hardness and Young’s modulus, were measured. In addition, the corrosion tests were performed using the OCP, EIS, and PD methods in Ringer’s solution within the independent pH range at 37°C. A ball-on-disc tribometer was used to investigate the tribological behavior of the alloys under various loads and wet conditions using the Ringer solution. It has been verified that Zr content (at. %) in the alloys had an impact on their morphologies, structural evolution, and mechanical characteristics. According to the morphological analysis, the particle and crystallite size decreases with increasing Zr content. Young’s modulus and Vickers hardness show the same tendency. The EIS data demonstrated that a single passive film formed on the alloy surfaces, and the addition of Zr enhanced the corrosion resistance of the passive films. The polarization curves demonstrate that the alloys had low corrosion current densities and large passive areas without the passive films disintegrating. Likewise, the inclusion of Zr resulted in a reduction in the corrosion and passive current density values. All of these results suggested that the titanium alloys exhibit a more noble electrochemical activity caused by Zr. From the tribological perspective, it was found that the friction coefficient of the alloys reduced with increasing Zr content. N2 - Um Legierungen mit außergewöhnlichen Eigenschaften für orthopädische Anwendungen zu schaffen, konzentriert sich diese Studie auf die Auswirkungen des Zirkonium (Zr)-Gehalts auf die strukturellen, elektrochemischen und tribologischen Eigenschaften von nanostrukturierten Ti-25NbxZr [x = 5, 10, 15, 20, 25 und 30 Atom-(at.) %] Legierungen. Die strukturelle Entwicklung wurde mit XRD- und SEM-Techniken untersucht. Die mechanischen Eigenschaften der hergestellten Legierungen, einschließlich der Vickershärte und des Elastizitätsmoduls, wurden gemessen. Darüber hinaus wurden die Korrosionstests mit den Methoden OCP, EIS und PD in Ringerlösung im unabhängigen pH-Bereich bei 37°C durchgeführt. Mit einem Kugel-Scheiben-Tribometer wurde das tribologische Verhalten der Legierungen unter verschiedenen Belastungen und nassen Bedingungen in Ringerlösung untersucht. Es wurde nachgewiesen, dass der Zr-Gehalt (in %) in den Legierungen einen Einfluss auf ihre Morphologie, strukturelle Entwicklung und mechanischen Eigenschaften hat. Die morphologische Analyse ergab, dass die Partikel- und Kristallitgröße mit zunehmendem Zr-Gehalt abnimmt. Elastizitätsmodul und Vickershärte zeigen die gleiche Tendenz. Die EIS-Daten zeigten, dass sich auf den Legierungsoberflächen ein einziger Passivfilm bildete, und der Zusatz von Zr erhöhte die Korrosionsbeständigkeit der Passivfilme. Die Polarisationskurven zeigen, dass die Legierungen niedrige Korrosionsstromdichten und große passive Flächen aufwiesen, ohne dass sich die Passivfilme auflösten. Ebenso führte der Zusatz von Zr zu einer Verringerung der Korrosions- und Passivstromdichtewerte. Alle diese Ergebnisse deuten darauf hin, dass die Titanlegierungen eine edlere elektrochemische Aktivität aufweisen, die durch Zr verursacht wird. Aus tribologischer Sicht wurde festgestellt, dass der Reibungskoeffizient der Legierungen mit zunehmendem Zr-Gehalt abnahm. KW - Ti-Nb-Zr alloys KW - Nanobiomaterials KW - Tribological behavior KW - Ringer's solution KW - Biomedical applications KW - Ti-Nb-Zr-Legierungen KW - Nanowerkstoffe KW - Tribologisches Verhalten KW - Ringerlösung KW - Biomedizinische Anwendungen KW - Biomedizin KW - Nanostrukturiertes Material KW - Titanlegierung KW - Zirconium Y1 - 2024 U6 - https://doi.org/10.1016/j.jsamd.2024.100695 SN - 2468-2179 VL - 9 IS - 2 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Krishna, Ajay A1 - Schiffer, Johannes A1 - Raisch, Jörg T1 - Distributed secondary frequency control in microgrids : robustness and steady-state performance in the presence of clock drifts T1 - Verteilte Sekundärfrequenzregelung in Mikronetzen : Robustheit und stationäre Leistung in Anwesenheit von Taktdifferenzen N2 - Microgrids are distributed systems with high share of inverter-interfaced renewable energy sources where stable and reliable system operation is realized by suitably controlling the inverters. In this work, we focus on secondary frequency control, which is an important ancillary service provided by the inverters. In the literature on secondary frequency control, the effect of clock drifts has often been neglected. However, clock drifts are practically unavoidable parameter uncertainties in inverter-based microgrids and we show that the most commonly employed distributed secondary frequency controllers exhibit performance deteriorations when taking clock drifts explicitly into consideration. Motivated by this, we propose a novel alternative control law called generalized distributed averaging integral (GDAI) control, which achieves the secondary control objectives of steady-state accurate frequency restoration and proportional power sharing in the presence of clock drifts. In addition, we derive a sufficient tuning criterion in the form of a set of linear matrix inequalities (LMIs) which guarantees robust stability of the closed-loop equilibrium point in the presence of uncertain clock drifts. Finally, our analysis is validated extensively via simulation with comprehensive comparisons to other related distributed control approaches. N2 - Mikronetze sind dezentrale Systeme mit einem hohen Anteil an erneuerbaren Energiequellen, bei denen ein stabiler und zuverlässiger Systembetrieb durch eine geeignete Regelung der Wechselrichter erreicht wird. In dieser Arbeit konzentrieren wir uns auf die sekundäre Frequenzregelung, die eine wichtige Zusatzfunktion der Wechselrichter darstellt. In der Literatur zur Sekundärfrequenzregelung wurde die Auswirkung von Taktdifferenzen oft vernachlässigt. Taktdifferenzen sind jedoch praktisch unvermeidbare Parameterunsicherheiten in umrichterbasierten Mikronetzen, und wir zeigen, dass die am häufigsten eingesetzten verteilten Sekundärfrequenzregler Leistungseinbußen aufweisen, wenn Taktdifferenzen explizit berücksichtigt werden. Aus diesem Grund schlagen wir ein neuartiges, alternatives Regelungsgesetz vor, das als verallgemeinertes verteiltes Mittelwertintegral (GDAI) bezeichnet wird und die sekundären Regelungsziele der genauen Frequenzwiederherstellung im stationären Zustand und der proportionalen Leistungsaufteilung in Anwesenheit von Taktdifferenzen erreicht. Darüber hinaus leiten wir ein hinreichendes Entwurfskriterium der Reglerverstärkungsfaktoren in Form einer Reihe von linearen Matrixungleichungen (LMIs) ab, welches robuste Stabilität des Gleichgewichtspunktes im geschlossenen Regelkreis bei unsicheren Taktschwankungen garantiert. Abschließend wird unsere Analyse durch Simulationen und umfassende Vergleiche mit anderen verwandten dezentralen Regelungsansätzen umfassend validiert. KW - Microgrids KW - Distributed control KW - Consensus algorithms KW - Power systems KW - Secondary frequency control KW - Sekundärfrequenzregelung KW - Mikronetze KW - Robustheit KW - Taktdifferenzen KW - Wechselrichter KW - Microgrid KW - Wechselrichter KW - Taktfrequenz Y1 - 2020 U6 - https://doi.org/10.26127/BTUOpen-5969 ER - TY - JOUR A1 - Çelik, Gülşah Aktaş A1 - Atapek, Şaban Hakan A1 - Polat, Şeyda A1 - Obrosov, Aleksei A1 - Weiß, Sabine T1 - Nitriding effect on the tribological performance of CrN-, AlTiN-, and CrN/AlTiN-Coated DIN 1.2367 hot work tool steel T1 - Auswirkung des Nitrierens auf das tribologische Verhalten von CrN-, AlTiN- und CrN/AlTiN-beschichteten DIN 1.2367 Warmarbeitsstählen JF - Materials N2 - In this study, heat-treated and multisurface engineered DIN 1.2367 tool steel was subjected to room and elevated temperature wear tests, and the effect of nitriding on its tribological behavior was investigated. CrN, AlTiN, and CrN/AlTiN coatings with a total thickness of 2 µm were obtained by arc cathodic physical vapor deposition on conventional heat-treated and gas-nitrided steels. The white layer formed during nitriding was removed, and a diffusion layer (100 µm) was achieved in the cross section of the steel having a tempered martensitic matrix. The highest surface hardness was attained with an integral coating (CrN/AlTiN), and surface hardness increased even more after nitriding due to the formation of a multicomponent ceramic layer on top of the diffusion layer. The room temperature wear tests performed against an alumina counterpart revealed that (i) CrN/AlTiN-coated steel had the highest friction coefficient of 0.26, which further increased to 0.33 by nitriding due to the increase in shear strength, and that (ii) with increasing surface hardness, the specific wear rates (W) of the heat-treated and coated steels could be ranked as follows: WCrN/AlTiN < WAlTiN < WCrN. The wear rates decreased when nitriding was carried out prior to coating. In order to simulate the aluminum extrusion conditions, hot wear behavior of the surfaces against AA6080 alloy at 450 °C was investigated. The hot wear tests revealed that (i) high friction coefficients were reached due to the adhesive characteristic of aluminum to the surfaces, (ii) the nitrided and CrN/AlTiN-coated sample exhibited the lowest wear rate among all studied surfaces, and (iii) the film damage on the worn surfaces mostly occurred in the form of droplet delamination. N2 - In dieser Studie wurde wärmebehandelter und mehrschichtig bearbeiteter Werkzeugstahl DIN 1.2367 bei Raum- und erhöhter Temperatur Verschleißtests sowie der Einfluss des Nitrierens auf sein tribologisches Verhalten untersucht. Auf konventionell wärmebehandelten und gasnitrierten Stählen wurden CrN-, AlTiN- und CrN/AlTiN-Schichten mit einer Gesamtdicke von 2 µm durch kathodische Gasphasenabscheidung erzeugt. Die beim Nitrieren gebildete weiße Schicht wurde entfernt, und es wurde eine Diffusionsschicht (100 µm) im Querschnitt des Stahls mit angelassener martensitischer Matrix erzeugt. Die höchste Oberflächenhärte wurde mit einer integralen Beschichtung (CrN/AlTiN) erreicht, die nach dem Nitrieren aufgrund der Bildung einer Mehrkomponenten-Keramikschicht auf der Diffusionsschicht noch weiter anstieg. Die bei Raumtemperatur durchgeführten Verschleißtests mit einem Aluminiumoxid-Gegenstück ergaben, dass (i) CrN/AlTiN-beschichteter Stahl den höchsten Reibungskoeffizienten von 0,26 aufwies, der sich nach dem Nitrieren aufgrund der erhöhten Scherfestigkeit auf 0,33 erhöhte, (ii) mit zunehmender Oberflächenhärte die spezifischen Verschleißraten (W) der wärmebehandelten und beschichteten Stähle wie folgt eingestuft werden konnten: WCrN/AlTiN 0.99), though absolute values were elevated due to excess surfactant oxidation. Temperature variation (5 and 20 °C) and mild heating of coconut fat (30–32 °C) showed no significant effect on COD reproducibility, indicating that mixing time and surfactant dosage are the dominant factors influencing measurement accuracy. Overall, the study establishes T80 as a reliable surfactant for solubilizing oily matrices, providing a consistent and repeatable approach for COD assessment of wastewater containing FOG. The proposed method offers a practical basis and a step towards environmental monitoring and process control in decentralized and industrial wastewater treatment systems. KW - Chemical oxygen demand KW - Fat KW - Oil KW - Wastewater KW - Tween 80 Y1 - 2025 U6 - https://doi.org/10.3390/chemengineering9060138 SN - 2305-7084 VL - 9 IS - 6 PB - MDPI CY - Lausanne ER - TY - CHAP A1 - Lengenfeld, Jonas T1 - The complex masonry of the Schönburg Castle Keep chimney system (1201 CE) in the context of contemporary examples T1 - Die komplexe Steinplanung im Kaminsystem des Bergfriedes der Schönburg bei Naumburg (1201 n.Chr.) im Kontext zeitgenössischer Vergleiche N2 - High Medieval chimneys, although often the focal point of contemporary representative buildings, are rarely a topic of construction history. More often they appear in art or architectural history where they are discussed regarding their style and ornamentation. It is however worthwhile to examine these important representative objects with the tools of the construction historian. In them, we can find important information regarding the contemporary craftsmanship and skills. Based on extensive firsthand examinations and building archaeology this paper aims to discuss the planning and building process of the highly complex cut-stone chimney system in the keep of Schönburg Castle (1201 CE) using new methods of reverse engineering. N2 - Obgleich hochmittelalterliche Kamine oft eine zentrale Stellung in zeitgenössischen repräsentativen Bauten einnehmen sind sie nur selten Thema der Bautechnikgeschichte. Häufiger sind sie Thema der Kunst und Architekturgeschichte welche sich auf Ihre Gestaltung und Ornamentik konzentriert. Es ist jedoch aufschlussreich diese wichtigen Repräsentationsobjekte mit den Mitteln der historischen Bauforschung zu betrachten da Sie uns Informationen zu den zeitgenössischen Fähigkeiten und Techniken offenbaren. Basierend auf ausführlichen bauforscherischen Untersuchungen bespricht diese Arbeit den Bau und Konstruktionsprozess des hochkomplexen Werksteinkaminsystems im Bergfried der Schönburg bei Naumburg unter Verwendung neuer Methoden des reverse engineerings. KW - Chimney KW - Medieval KW - Reverse engineering KW - Building archaeology KW - Kamin KW - Mittelalter KW - Bauforschung KW - Schönburg KW - Werkstein KW - Schönburg Naumburg, Saale KW - Kamin KW - Geschichte Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:co1-opus4-59801 N1 - Autorenmanuskript, erschienen in: Timber and building construction : proceedings of the ninth annual conference of the Construction History Society / Construction History Society (Editor). - Cambridge : Construction History Society, 2022. - S. 23-38 ER - TY - BOOK ED - Rosen, Christian ED - Gribat, Nina T1 - Hybrid urbanisms in secondary cities of the global south : insights from urban planning and infrastructure delivery in Ghana and Peru N2 - This book presents the concept of Hybrid Urbanisms aiming to deconstruct the still-existing and often critiqued dualism of formalised and informalised practices in urban planning and infrastructure delivery. Using an innovative perspective, the book addresses this issue by focusing on the complex configurations in which both forms always co-exist and compete as powerful social constructs. It unveils the juxtaposition, simultaneity, dependency and intertwining of in-/formalised practices and highlights the relevance of this perspective to better understand urban development, especially in the global South. At the same time, the book focuses on secondary cities of Ghana and Peru that are often overlooked in the existing literature but play a relevant role in global urbanisation quantitively and qualitatively. In offering a comparative perspective on two very diverse geographical contexts, ten empirical studies are framed by a conceptualisation of ‘Hybrid Urbanisms’ and a concluding systematisation of perspectives on this central aspect of urban development. Taken together, this volume makes an innovative contribution on how to produce new and more diverse urban theories of cities of the global South. This book is essential for scholars, students and practitioners in the fields of urban planning, urban studies, infrastructure studies and international cooperation alike. In addition, it will be of interest to those in the fields of urban sociology, public policy, urban geography and development studies. This publication was supported by funds from the Publication Fund for Open-Access Monographs of the Federal State of Brandenburg, Germany and by the Faculty of Architecture, Civil Engineering and Urban Planning of Brandenburg University of Technology Cottbus-Senftenberg. KW - Geography KW - Global development KW - Urban studies Y1 - 2025 SN - 978-1-003-51113-7 U6 - https://doi.org/10.4324/9781003511137 PB - Routledge CY - London ER - TY - CHAP A1 - Schmitt, Rebecca Erika A1 - Wendland, David T1 - The geometric design of the “Guarinesque” vaults in Banz and Vierzehnheiligen in relation to the treatises of stereotomy T1 - Der geometrische Entwurf der "Guarinesken" Gewölbe in Banz und Vierzehnheiligen in Beziehung zu den Traktaten der Stereotomie N2 - Johann Dientzenhofer’s Banz Abbey Church (1710-1718) and Balthasar Neumann’s church of Vierzehnheiligen (1743-1772), both located in Upper Franconia (Germany), are characterised by their masonry vaults, sequences of oval domes separated by double-curved arches. This Late Baroque architecture has been called “Guarinesque”; however, the conceptual connection between the vaults and Guarino Guarini’s architecture remains to be thoroughly investigated. This paper resumes the discussion about the geometric definitions of these vaults using the modern methods of geometric analysis and reverse geometrical engineering, based on 3D laser scanning. The analysis of these scans reveals a design process based on plane circle segments and ovals, while more complex geometric procedures are not necessary to describe the vaults. Further, the relationship between these designs and the procedures of geometric design described in the treatises of stereotomy since the 16th century can be shown. On this background, the relation to Guarini’s Architettura Civile (1737) is discussed. N2 - Die Klosterkirche von Banz (1710-1718) von Johann Dientzenhofer und die Kirche Vierzehnheiligen (1743-1772) von Balthasar Neumann, beide in Oberfranken (Deutschland) gelegen, zeichnen sich durch ihre gemauerten Gewölbe aus, Abfolgen von ovalen Kuppeln, die durch doppelt gekrümmte Bögen getrennt sind. Diese spätbarocke Architektur ist als "guarinesk" bezeichnet worden; der konzeptionelle Zusammenhang zwischen den Gewölben und der Architektur Guarino Guarinis ist jedoch noch nicht eingehend untersucht worden. In diesem Beitrag wird die Diskussion über die geometrischen Definitionen dieser Gewölbe mit Hilfe der modernen Methoden der geometrischen Analyse und des Reverse Geometrical Engineering auf der Grundlage von 3D-Laserscans wieder aufgenommen. Die Analyse dieser Scans zeigt einen Entwurfsprozess, der auf ebenen Kreissegmenten und Ovalen beruht, während komplexere geometrische Verfahren zur Beschreibung der Gewölbe nicht erforderlich sind. Darüber hinaus kann die Verwandtschaft zwischen diesen Entwürfen und den in den Abhandlungen der Stereotomie seit dem 16. Jahrhundert beschriebenen geometrischen Entwurfsverfahren aufgezeigt werden. Vor diesem Hintergrund wird auch die Beziehung zu Guarinis Architettura Civile (1737) erörtert. KW - Balthasar Neumann KW - Johann Dientzenhofer KW - Vierzehnheiligen KW - Banz KW - Vault KW - Gewölbe KW - Klosterkirche Banz (Bad Staffelstein) KW - Wallfahrtskirche Vierzehnheiligen (Staffelstein) KW - Kirchenbau KW - Gewölbe KW - Dreidimensionale Rekonstruktion KW - Geometrie Y1 - 2021 U6 - https://doi.org/10.26127/BTUOpen-5904 ER - TY - CHAP A1 - Wendland, David A1 - Gielen, Mark T1 - The design and construction of the vaults in Notre-Dame in Paris and the development of medieval vaulting and stereotomy : surveys, analyses and experiments T1 - Entwurf und Konstruktion der Gewölbe in Notre-Dame in Paris und die Entwicklung von mittelalterlichem Gewölbebau und Stereotomie : Bauuntersuchungen, Analysen und Experimente N2 - Among the many innovative church constructions in the Île-de-France during the twelfth century that immediately followed the ground-breaking new building of the abbey church of Saint-Denis, the high vaults in the cathedral of Notre-Dame in Paris mark a turning point – both in sheer dimensions and in their quality of execution as stone constructions. On the other hand, some solutions in design and construction that can be observed in these vaults remain unique within the dynamic development of Gothic vaulting in the great cathedrals built in the following years. On closer view it turns out that the general design of the vault as well as its construction details are hardly understood until now, mainly because they have been overlooked in a unifying perspective on Gothic architecture coined by the idealistic view of the Gothic Revival in the nineteenth century. Further, the particular relation between vault design and stereotomy needs to be clarified, and its significance needs to be understood. N2 - Innerhalb der zahlreichen innovativen Kirchenbauten, die während des 12. Jahrhunderts in der Île-de-France in unmittelbarer Nachfolge der wegweisenden Neubauten an der Abteikirche von Saint-Denis entstanden, stellen die Hochschiffgewölbe der Kathedrale von Notre-Dame in Paris einen Wendepunkt dar – sowohl in den schieren Abmessungen, als auch in ihrer herausragenden Qualität als Werksteinkonstruktion. Zugleich lassen sich in diesen Gewölben einige Lösungen in Entwurf und Konstruktion beobachten, die innerhalb der dynamischen Entwicklung des gotischen Gewölbebaus in den Kathedralen, die in den Folgejahren errichtet wurden, singulär bleiben. Bei näherer Betrachtung erweist sich, dass der Gesamtentwurf dieser Gewölbe wie auch die konstruktiven Details bis heute kaum verstanden sind – vor allem, weil sie in der durch den idealisierenden Blick des Gothic Revival im 19. Jahrhundert geprägten vereinheitlichenden Sicht auf die gotische Architektur übersehen wurden. Ferner bedarf die besondere Beziehung zwischen Gewölbeentwurf und Stereotomie der Klärung und ihre Bedeutung eines näheren Verständnisses. KW - Vault KW - Medieval architecture KW - Gothic KW - Notre-Dame de Paris KW - Speyer Cathedral KW - Gewölbe KW - Mittelalterliche Architektur KW - Gotik KW - Dom zu Speyer KW - Notre-Dame (Paris) KW - Kirchenbau KW - Gewölbe KW - Gotik Y1 - 2022 U6 - https://doi.org/10.26127/BTUOpen-6060 ER - TY - JOUR A1 - Weiss, Romano A1 - Liedtke, Victoria A1 - Stefan, Rödiger T1 - Cannabidiol does not cause DNA double-strand breaks in a human liver-derived cell model JF - Journal of Cannabis Research N2 - 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. KW - Cannabidiol KW - DNA damage KW - Proliferation KW - CAMP KW - HepG2 Y1 - 2025 U6 - https://doi.org/10.1186/s42238-025-00365-w SN - 2522-5782 VL - 8 IS - 12 PB - BMC CY - London ER - TY - JOUR A1 - Otto, Pascal A1 - Puchol‑Royo, Roser A1 - Ortega‑Legarreta, Asier A1 - Tanner, Kristie A1 - Tideman, Jeroen A1 - Vries, Sjoerd‑Jan de A1 - Pascual, Javier A1 - Porcar, Manuel A1 - Latorre‑Pérez, Adriel A1 - Abendroth, Christian T1 - Multivariate comparison of taxonomic, chemical and operational data from 80 different full‑scale anaerobic digester‑related systems JF - Biotechnology for Biofuels and Bioproducts N2 - 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. KW - Anaerobic digestion KW - 16S rRNA sequencing KW - Core microbiome KW - Multivariate analysis KW - Parameter dependency KW - Gärung KW - Mikrobiom KW - Multivariate Analyse KW - Laborparameter Y1 - 2024 U6 - https://doi.org/10.1186/s13068-024-02525-1 SN - 2731-3654 VL - 17 PB - BMC CY - London ER - TY - JOUR A1 - Kim, Dongsuk A1 - Gerstberger, Ulf A1 - Asli, Majid A1 - Höschler, Klaus T1 - U-Net Driven Semantic Segmentation for Detection and Quantification of Cracks on Gas Turbine Blade Tips JF - Results in Engineering N2 - 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. KW - Crack detection KW - Semantic segmentation KW - Gas turbine blade KW - U-Net KW - Deep learning KW - Convolutional neural network Y1 - 2025 U6 - https://doi.org/10.1016/j.rineng.2025.108864 SN - 2590-1230 VL - 29 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Oleynik, Paul A1 - Ryzhak, Diana A1 - Schlipf, Jon A1 - Alvarado Chavarin, Carlos A1 - Yamamoto, Yuji A1 - Berkmann, Fritz A1 - Ratzke, Markus A1 - Fischer, Inga Anita T1 - Influence of illumination conditions on photoluminescence enhancement in an Al/Si/Ge metasurface JF - Optics Express N2 - 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. KW - Field enhancement KW - Germanium KW - Light emitting diodes KW - Photonic crystals KW - Quantum light sources KW - Scanning electron microscop Y1 - 2025 U6 - https://doi.org/10.1364/OE.577751 SN - 1094-4087 VL - 34 IS - 1 SP - 78 EP - 86 PB - Optica Publishing Group CY - Washington D.C. ER - TY - JOUR A1 - Malk, Konrad A1 - Riedel, Ramona A1 - Hinz, Christoph A1 - Fischer, Thomas A1 - Martienssen, Marion T1 - Adsorption of phosphonates to iron- or aluminum-based flocculants in wastewater treatment JF - Water N2 - In this study, we investigated the impact of varying iron (Fe) and aluminum (Al) contents on the adsorption of phosphonates to activated sludge. Phosphonates originating from household applications account for up to 40% of the non-reactive dissolved phosphorus in domestic sewage treatment plants and thus can contribute to the eutrophication of water bodies. Although these substances are not readily degradable, substantial quantities, ranging from 40% to more than 90%, are removed by sludge adsorption. The results demonstrate a strong correlation between the adsorption of aminophosphonates and the Fe3+ content of the sludge. The maximum phosphonate loadings were 5.94 mmol g−1 Fe3+ for ATMP, 4.94 mmol g−1 Fe3+ for EDTMP, 4.74 mmol g−1 Fe3+ for DTPMP, and 2.25 mmol g−1 Fe3+ for glyphosate. In contrast to pure ferric hydride flocs, the adsorption of phosphonates was approximately threefold higher when the hydroxides were located within activated sludge flocs. It is concluded that native sludge flocs provide larger iron surfaces than ferric hydroxide alone. Based on the weight of the adsorbents, aluminum salts were four times less efficient than ferric salts. In sludge without ferric or aluminum hydroxides, phosphonate adsorption was negligible. KW - Adsorption KW - Activated sludge KW - Ferrous oxide KW - Phosphonates KW - Wastewater treatment Y1 - 2025 U6 - https://doi.org/10.3390/w18010116 SN - 2073-4441 VL - 18 IS - 1 PB - MDPI CY - Basel ER - TY - JOUR A1 - Sengül, Akant A1 - Reiter, Sebastian A1 - Lotfi, Zahra A1 - Efremenko, Julia A1 - Laroussi, Arwa A1 - Corley-Wiciak, Agnieszka Anna A1 - Ratzke, Markus A1 - Mirsky, Vladimir M. A1 - Wenger, Christian A1 - Fischer, Inga Anita T1 - Titanium nitride plasmonic nanohole arrays with polymer coating : optical properties and their humidity-induced modifications JF - Optical Materials Express N2 - The use of titanium nitride (TiN) for the fabrication of plasmonic structures such as nanohole arrays (NHAs) can enable their integration into optoelectronic devices on the silicon (Si) platform, for example, for the realization of on-chip chemical sensors and biosensors based on refractometric transduction. With a corresponding functionalization of the TiN nanohole arrays, these ultra-compact devices can be utilized in the development of various affinity sensors and sensor systems, such as cost-effective electronic noses for the early detection of gases in the food industry or agriculture. In this work, we focus on two types of coating for functionalization of TiN nanohole arrays: electrochemically synthesized poly-N-methylaniline and layer-by-layer deposited polyacrylic-acid/poly-allylamine (PAA/PAH). Our investigation comprises the experimental characterization of the optical properties of TiN nanhole arrays coated with polymer layers of different thicknesses as well as a comparison with simulation results. We demonstrate the potential of our setup sensing applications by measuring changes in optical properties of TiN nanohole arrays coated with PAA/PAH upon exposure to air of different humidity. KW - Chemical sensors KW - Extraordinary optical transmission KW - Localized surface plasmon resonance KW - Optical coatings KW - Optical properties KW - Refractive index Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:co1-opus4-72739 SN - 2159-3930 VL - 16 IS - 2 SP - 184 EP - 196 PB - Optica Publishing Group CY - Washington D.C. ER - TY - JOUR A1 - Sharma, Dikshant A1 - Radomsky, Lukas A1 - Mathiazhagan, Akilan A1 - Asli, Majid A1 - Höschler, Klaus A1 - Mallwitz, Regine T1 - Thermal analysis of metal foam integrated heatsink for electrified aircraft applications JF - International Journal of Thermofluids N2 - Metal foams facilitate large heat dissipation in high-power dense systems such as power electronics for electrified propulsion application. This work addresses the cooling of a power semiconductor device with aluminium and copper metal foam integrated hybrid heatsink and its comparative analysis to a conventional finned heatsink using 0D and 3D modelling approach. Two-equation foam model in Fluent is utilized and the numerical approach is validated against experimental dataset. Inlet air velocity is varied such that the Darcy to turbulent regimes of the open-cellular foams are covered. Foam porosities from ∼ 0.85−0.95 with 10–20 PPI are investigated and the thermal performance of the heatsink is found to be independent of the foam material. High porosity (> 0.9), 20 PPI foams are found to aid forced-convection by improving the thermal resistance by more than 10% against the 10 PPI counterparts. The hybrid heatsink outperforms the foam-based and conventional heatsink by 40% and 15% respectively when considering the reduction in junction temperatures, while the hydraulic resistance increases 10 times when compared to the conventional one. The 0D thermal resistance model is robust in predicting the junction temperatures for metal foam heatsinks with only a 5%–6% discrepancy for both the 50 W and 100 W heat load scenarios. The key and novel contribution of this study is the integration of detailed 3D simulations of a power electronics cooling environment with the development of a corresponding 0D thermal model. This approach not only eases the physical representation of the system but also enables the model to be extended to diverse heat load conditions. KW - Electric propulsion KW - Electronics thermal management KW - Metal foam heatsink KW - Porous media KW - Forced convection Y1 - 2025 U6 - https://doi.org/10.1016/j.ijft.2025.101465 SN - 2666-2027 VL - 30 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Julia, Zscherneck A1 - Julia, Binder A1 - Tobias, Mettenberger T1 - Rural network assemblages : disentangling egocentric networks of digital pioneers in peripheral German regions JF - Regional studies, regional science N2 - Digital solutions are seen as promising ways of addressing current challenges in rural regions. Individual or group key actors accessing resources foster these developments through networks. In light of regional clustering and agglomeration effects on the one hand and increased virtual mobility on the other hand, assumptions about the spatiality of such networks are highly controversial. Our paper takes this as a point of departure, asking how spatiality is constructed in the networks of so-called ‘digital pioneers’ (DPs). The sampling process took place in two German rural regions with different preconditions for digital technology adoption, where we conducted egocentric network analysis and qualitative interviews. Employing the assemblage perspective, we analysed networks of 30 individuals in terms of the analytical categories of territoriality, stability and connectivity. Our findings distinguish between three important roles of network contacts: (1) multipliers in social networking, (2) users of the DP’s products and services, as well as (3) close family members that are important in professional contexts. Although DPs are often deeply embedded in and feel attached to their region, networks vary significantly in their territorial radius, also including highly functional problem-solving contacts to distant places. Consequently, our evidence challenges static territorial models of innovation processes, advocating for processual and multidimensional perspectives that consider social networks and individual agency. Likewise, our study complements current research on rural governance by shifting the focus from key institutions and formal networks to less formally integrated actors and problem-solving networks. KW - Qualitative network analysis KW - Assemblage KW - Bridging and bonding ties KW - Peripheral regions Germany Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:co1-opus4-72787 SN - 2168-1376 VL - 12 IS - 1 SP - 996 EP - 1012 PB - Routledge CY - London ER - TY - JOUR A1 - Yang, Yinghui A1 - Henke, Markus A1 - Möhlenkamp, Georg T1 - Analytical investigation of short-circuit protection and post-fault operation in dual three-phase PMSMs for hybrid electric counter-rotating compressor applications JF - IEEE Access N2 - The hybrid electric counter-rotating compressor (CRC) has the potential to improve power-specific fuel consumption in aircraft engines. However, due to its cascaded structure, a reduction or loss of driving power in a single compressor stage can significantly degrade the overall compressor performance. A short-circuit fault is a typical electrical failure in an electric motor that can lead to a complete loss of driving power. One innovative post-fault operation strategy is to utilize the braking capability of the failed motor at low speed to lock its corresponding compressor stage. In this way, the failed stage can function as a stator stage, still providing degraded flow-guiding capability and preventing reverse rotation. This article investigates the short-circuit protection strategy and post-fault operation of dual three-phase permanent magnet synchronous motors (DTP-PMSMs) for hybrid electric CRC applications. Analytical models are developed to characterize the post-fault behavior of the DTP-PMSM. Key design factors are defined, and their influence on post-fault performance is analyzed. Critical post-fault operating points are identified to evaluate and compare different protection strategies. Based on these results, an optimized shortcircuit protection strategy is proposed for DTP-PMSMs in CRC applications. Finally, the analytical findings and the proposed strategy are validated through simulation. KW - Windings KW - Circuit faults KW - Rotors KW - Torque KW - Protection Y1 - 2025 U6 - https://doi.org/10.1109/ACCESS.2026.3658195 SN - 2169-3536 VL - 14 SP - 17303 EP - 17323 PB - IEEE CY - New York ER - TY - JOUR A1 - Mbuya, Christel Olivier Lenge A1 - Pawar, Kunal A1 - Jafari, Mitra A1 - Shafiee, Parisa A1 - Okoye Chine, Chike George A1 - Tarifa, Pilar A1 - Dorneanu, Bogdan A1 - Arellano-Garcia, Harvey T1 - Tuning catalyst performance in methane dry reforming via microwave irradiation of nickel-silicon carbide systems JF - Journal of CO2 Utilization N2 - The dry reforming of methane (DRM) is a promising route for converting greenhouse gases such as methane (CH4) and carbon dioxide (CO2) into valuable syngas, hydrogen (H2) and carbon monoxide (CO). However, traditional nickel (Ni)-based catalysts suffer from rapid deactivation due to carbon deposition and sintering, especially when supported on low thermal conductivity materials. In this work, a novel post-synthesis microwave irradiation (MIR) treatment is introduced to systematically optimize the performance of Ni – β – SiC and Ni – Ti – Cβ – SiC catalysts for DRM. Unlike previous studies that have used MIR during reaction or with different supports, this approach tunes the metal – support interactions and textural properties of Ni – β – SiC and Ni – Ti – Cβ – SiC catalysts by varying the MIR exposure time after catalyst synthesis. MIR post-treatment (10–25 s) increased the CH4 conversion to 65 % and the CO2 conversions to 62 % for Ni–β–SiC catalysts and improved the H₂/CO ratio to 0.80, with stable performance over 20 h. For Ni–Ti–Cβ–SiC, MIR (10–20 s) maintained CH4 conversion up to 60 % and CO2 conversion to 58 % over 20 h, while the untreated catalyst, though initially higher, deactivated rapidly. Excessive MIR (30 s) reduced performance for both catalyst types, underscoring the need for optimal exposure time. These findings demonstrate post-synthesis MIR provides a tuneable approach for enhancing both the activity and durability of Ni/SiC – based DRM catalysts through controlled modification of metal – support interactions. This work offers new insights for the design of robust catalysts aimed at greenhouse gas utilization and sustainable syngas production, with activity and stability enhancements linked to controlled changes in metal – support interactions. KW - Carbon dioxide KW - Dry reforming KW - Methane KW - Microwave irradiation KW - Ni Silicon carbide catalysts Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:co1-opus4-72832 SN - 2212-9820 VL - 102 PB - Elsevier CY - Amsterdam ER -