@inproceedings{59873,
abstract = {{This paper focuses on the failure behavior of clinched specimens with various stiffnesses under shear tensile loading. The primary objective is to assess the influence of the specimen stiffness with an arrangement of clinched joints. The specimen stiffness depends on several variables. In addition to the material selection, the specific choice of geometry and the design of the clinched joints must also be taken into account. A number of experiments was conducted to investigate the failure behavior of specimens with an arrangement of three clinched joints under shear tensile loading. These configurations were subjected to shear tensile tests, with force displacement curves recorded for each specimen to provide a detailed characterization of their structural response. The stiffness is modified by altering the specimen width, which has marginal impact on the maximum force. The experimental findings indicate that reducing the specimen stiffness results in a shift in the type of stress, with the failure behavior becoming increasingly influenced by bending stress. These results offer important insights for the design of clinched joint assemblies, indicating that it is feasible to achieve the desired properties by changing the specimen stiffness.}},
author = {{Wolf, Eugen and Brosius, Alexander}},
booktitle = {{MATEC Web of Conferences}},
issn = {{2261-236X}},
keywords = {{Joining, Sheet Metal, Stiffness, Clinching}},
location = {{Lisbon}},
publisher = {{EDP Sciences}},
title = {{{Investigation failure behavior in the shear tensile test with variety of specimen stiffness}}},
doi = {{10.1051/matecconf/202540801080}},
volume = {{408}},
year = {{2025}},
}
@inproceedings{59485,
abstract = {{This paper focuses on the failure behavior of specimens with various configurations of clinched joints under shear tensile loading. The primary objective is to assess the influence of the joining direction and the spatial arrangement of clinched joints on their mechanical performance. A number of experiments was conducted, focusing on three clinched joints arranged in different configurations, each varying in terms of joining direction and spacing. These configurations were subjected to shear tensile tests, with force-displacement curves recorded for each sample to provide a detailed characterization of their structural response. The experimental findings indicate that the specific arrangement of the clinched joints, in terms of joining direction, has a marginal impact on the overall failure behavior. This suggests that intricate modifications to the joining direction are unnecessary to achieve improved mechanical performance in such applications. These results offer valuable insights for the design of clinched joint assemblies, indicating that simplified joining strategies may suffice without compromising structural integrity under shear loading.}},
author = {{Wolf, Eugen and Brosius, Alexander}},
booktitle = {{Materials Research Proceedings}},
issn = {{2474-395X}},
keywords = {{Joining, Sheet Metal, Clinching}},
location = {{Paderborn}},
pages = {{ 86 -- 92}},
publisher = {{Materials Research Forum LLC}},
title = {{{Investigation failure behavior in the shear tensile test with respect to the arrangements of clinched joints}}},
doi = {{10.21741/9781644903551-11}},
volume = {{52}},
year = {{2025}},
}
@inproceedings{60290,
abstract = {{The constantly increasing demand for climate protection and resource conservation requires innovative and versatile joining processes that improve adaptability to the joining task and robustness to enable flexible manufacturing on a production line. Therefore, the versatile SPR (V-SPR) and tumbling SPR (T-SPR) were developed. Using the example of a mixed material combination HCT590X+Z (t0 = 1.0 mm) / EN AW-6014 T4 (t0 = 2.0 mm), these processes were examined and compared with regard to the binding mechanisms form closure and force closure using micrographs, non-destructive resistance measurements and destructive torsion tests. For this purpose, a new sample geometry was defined, and the methods were adapted to the SPR process variants.}},
author = {{Lüder, Stephan and Holtkamp, Pia Katharina and Wituschek, Simon and Bobbert, Mathias and Meschut, Gerson and Lechner, Michael and Schmale, Hans Christian}},
booktitle = {{Materials Research Proceedings}},
editor = {{Meschut, Gerson and Bobbert, Mathias and Duflou, Joost and Fratini, Livan and Hagenah, Hinnerk and Martins, Paulo A. F. and Merklein, Marion and Micari, Fabrizio}},
issn = {{2474-395X}},
keywords = {{Joining, Self-Piercing Riveting, Sheet Metal}},
location = {{Paderborn}},
pages = {{101 -- 108}},
publisher = {{Materials Research Forum LLC}},
title = {{{Analysis of the binding mechanisms depending on versatile process variants of self-piercing riveting}}},
doi = {{10.21741/9781644903551-13}},
volume = {{52}},
year = {{2025}},
}
@inproceedings{60285,
abstract = {{This paper examines the impact of a rotationally superimposed punch stroke on the binding mechanisms of clinched joints of aluminum sheets. As part of the development of a method for ensuring the versatility of clinching, an additional rotational movement of the punch was introduced as a control variable to influence friction in the mechanical joining process. The effect of rotational superimposition on the force-displacement curve of the clinching processes was investigated using four test variants with different kinematics. The primary objective was to evaluate the binding mechanisms that maintain the integrity of the clinched joint. To evaluate the force closure of the resulting joint, two testing methods were employed throughout the course of the research, non-destructive resistance measurement using four-wire sensing method and destructive torsion testing. A crucial factor influencing the efficacy of the process is surface cleanliness, as contaminants between joining partners can impede the effectiveness of the clinched joint. Therefore, all specimens were meticulously cleaned prior to experimentation. This method exhibits promising potential in creating clinched joints that align with the demands of flexible manufacturing environments.}},
author = {{Lüder, Stephan and Wolf, Eugen and Schmale, Hans Christian and Brosius, Alexander}},
booktitle = {{MATEC Web of Conferences}},
issn = {{2261-236X}},
keywords = {{Joining, Sheet Metal, Tribology, Clinching}},
location = {{Lisbon}},
publisher = {{EDP Sciences}},
title = {{{Investigation of the impact of a rotationally superimposed punch stroke on the binding mechanisms of a clinched joint}}},
doi = {{10.1051/matecconf/202540801086}},
volume = {{408}},
year = {{2025}},
}
@misc{64894,
abstract = {{This dataset contains experimental measurements of the radial dynamic and quasi-static characteristics of four different types of Rubber-Metal Bushings (RMBs) used in the suspension system of a passenger car under harmonic displacement excitation. For each bushing type, 2–3 individual specimens were tested.
Quasi-static measurements were performed at a constant excitation frequency of 0.05 Hz with varying displacement amplitudes. Dynamic measurements were conducted with displacement amplitudes ranging from 0.04 mm to 0.3 mm and excitation frequencies of 2, 5, 10, ..., up to 100 Hz.
The data is structured by bushing type, measurement mode, amplitude, and frequency, and is provided in *.csv and *.hrm format. It is intended to support further research in modeling rubber-metal bushings and parameter identification techniques.}},
author = {{Schütte, Jan}},
keywords = {{bushing, experimental data, rubber-metal-bushing, Dataset suspension}},
publisher = {{LibreCat University}},
title = {{{Experimental Dataset: Force and Displacement Measurements of Four Rubber-Metal Bushing Types from a Passenger Car under Harmonic Displacement Excitation}}},
doi = {{10.5281/ZENODO.14851317}},
year = {{2025}},
}
@article{55999,
abstract = {{Clean hydrogen is a key aspect of carbon neutrality, necessitating robust methods for monitoring hydrogen concentration in critical infrastructures like pipelines or power plants. While semiconducting metal oxides such as In2O3 can monitor gas concentrations down to the ppm range, they often exhibit cross-sensitivity to other gases like H2O. In this study, we investigated whether cyclic optical illumination of a gas-sensitive In2O3 layer creates identifiable changes in a gas sensor´s electronic resistance that can be linked to H2 and H2O concentrations via machine learning. We exposed nanostructured In2O3 with a large surface area of 95 m2 g-1 to H2 concentrations (0-800 ppm) and relative humidity (0-70%) under cyclic activation utilizing blue light. The sensors were tested for 20 classes of gas combinations. A support vector machine achieved classification rates up to 92.0%, with reliable reproducibility (88.2 ± 2.7%) across five individual sensors using 10-fold cross-validation. Our findings suggest that cyclic optical activation can be used as a tool to classify H2 and H2O concentrations.}},
author = {{Baier, Dominik and Krüger, Alexander and Wagner, Thorsten and Tiemann, Michael and Weinberger, Christian}},
issn = {{2227-9040}},
journal = {{Chemosensors}},
keywords = {{resistive gas sensor, chemiresistor, semiconductor, metal oxide, In2O3, mesoporous, hydrogen, humidtiy, machine learning, sustainable}},
number = {{9}},
pages = {{178}},
publisher = {{MDPI}},
title = {{{Gas Sensing with Nanoporous In2O3 under Cyclic Optical Activation: Machine Learning-Aided Classification of H2 and H2O}}},
doi = {{10.3390/chemosensors12090178}},
volume = {{12}},
year = {{2024}},
}
@article{57699,
abstract = {{The optimization of process parameters in powder Directed Energy Deposition (DED) is essential for achieving consistent, high-quality bead geometries, which directly influence the performance and structural integrity of fabricated components. As a subset of additive manufacturing (AM), the DED process, also referred to as laser metal deposition (LMD), enables precise, layer-by-layer material deposition, making it highly suitable for complex geometries and part repair applications. Critical parameters, such as the laser power, feed rate, powder mass flow, and substrate temperature govern the deposition process, impacting the bead height, width, contact angle, and dilution. Inconsistent control over these variables can lead to defects, such as poor bonding, dimensional inaccuracies, and material weaknesses, ultimately compromising the final product. This paper investigates the effects of various process parameters, specifically the substrate temperature, on bead track geometry in DED processes for stainless steel (1.4404). A specialized experimental setup, integrated within a DED machine, facilitates the controlled thermal conditioning of sample sheets. Using Design of Experiments (DoE) methods, individual bead marks are generated and analyzed to assess geometric characteristics. Regression models, including both linear and quadratic approaches, are constructed to predict machine parameters for achieving the desired bead geometry at different substrate temperatures. Validation experiments confirm the accuracy and reliability of the models, particularly in predicting the bead height, bead width, and contact angle across a broad range of substrate temperatures. However, the models demonstrated limitations in accurately predicting dilution, indicating the need for further refinement. Despite some deviations in measured values, successful fabrication is achieved, demonstrating robust bonding between the bead and substrate. The developed models offer insights into optimizing DED process parameters to achieve desired bead characteristics, advancing the precision and reliability of additive manufacturing technology. Future work will focus on refining the regression models to improve predictions, particularly for dilution, and further investigate non-linear interactions between process variables.}},
author = {{Chalicheemalapalli Jayasankar, Deviprasad and Gnaase, Stefan and Lehnert, Dennis and Walter, Artur and Rohling, Robin and Tröster, Thomas}},
issn = {{2075-4701}},
journal = {{Metals}},
keywords = {{additive manufacturing, direct energy deposition, laser metal deposition}},
number = {{12}},
publisher = {{MDPI AG}},
title = {{{Effect of Substrate Temperature on Bead Track Geometry of 316L in Directed Energy Deposition: Investigation and Regression Modeling}}},
doi = {{10.3390/met14121353}},
volume = {{14}},
year = {{2024}},
}
@article{56089,
abstract = {{Additive manufacturing (AM) technologies enable near-net-shape designs and demand-oriented material usage, which significantly minimizes waste. This points to a substantial opportunity for further optimization in material savings and process design. The current study delves into the advancement of sustainable manufacturing practices in the automotive industry, emphasizing the crucial role of lightweight construction concepts and AM technologies in enhancing resource efficiency and reducing greenhouse gas emissions. By exploring the integration of novel AM techniques such as selective laser melting (SLM) and laser metal deposition (LMD), the study aims to overcome existing limitations like slow build-up rates and limited component resolution. The study’s core objective revolves around the development and validation of a continuous process chain that synergizes different AM routes. In the current study, the continuous process chain for DMG MORI Lasertec 65 3D’s LMD system and the DMG MORI Lasertec 30 3D’s was demonstrated using 316L and 1.2709 steel materials. This integrated approach is designed to significantly curtail process times and minimize component costs, thus suggesting an industry-oriented process chain for future manufacturing paradigms. Additionally, the research investigates the production and material behavior of components under varying manufacturing processes, material combinations, and boundary layer materials. The culmination of this study is the validation of the proposed process route through a technology demonstrator, assessing its scalability and setting a benchmark for resource-efficient manufacturing in the automotive sector.}},
author = {{Chalicheemalapalli Jayasankar, Deviprasad and Gnaase, Stefan and Kaiser, Maximilian Alexander and Lehnert, Dennis and Tröster, Thomas}},
issn = {{2075-4701}},
journal = {{Metals}},
keywords = {{additive manufacturing (AM), selective laser melting (SLM), laser metal deposition (LMD), hybrid manufacturing, process optimization, 316L, 1.2709}},
number = {{7}},
publisher = {{MDPI AG}},
title = {{{Advancements in Hybrid Additive Manufacturing: Integrating SLM and LMD for High-Performance Applications}}},
doi = {{10.3390/met14070772}},
volume = {{14}},
year = {{2024}},
}
@article{55743,
abstract = {{The use of hybrid materials as a combination of fibre-reinforced plastic (FRP) and metal is of great interest in order to meet the increasing demands for sustainability, efficiency, and emission reduction based on the principle of lightweight design. These two components can therefore be joined using the intrinsic joining technique, which is formed by curing the matrix of the FRP component. In this study, for the hybrid joint, unidirectionally pre-impregnated semi-finished products (prepregs) with duromer matrix resin and micro-alloyed HC340LA steel were used. In order to conduct a detailed investigation, the damage mechanisms of intrinsically produced fibre metal laminates (FMLs), a new clamping device, and a novel pressing tool were designed and put into operation. The prepregs were prestressed by applying a preloading force using a specially designed prestressing frame. Hybrid specimens were then produced and subjected to nanoindentation and a shear tensile test. In particular, the effect of the residual stress state by varying the defined prestressing force on the damage mechanisms was studied. The results showed that no fracture patterns occurred in the interface of the specimens without preloading as a result of curing at 120 °C, whereas specimens with preloading failed at the boundary layer in the tensile range. Nevertheless, all specimens cured at 160 °C failed at the boundary layer in the tensile range. Furthermore, it was proven that the force and displacement of the preloaded specimens were promisingly higher than those of the unpreloaded specimens.}},
author = {{Irmak, Hayrettin and Tinkloh, Steffen Rainer and Marten, Thorsten and Tröster, Thomas}},
issn = {{2504-477X}},
journal = {{Journal of Composites Science}},
keywords = {{CFRP, prestressing, fibre metal laminate, interface, prepreg, shear tensile test}},
number = {{8}},
publisher = {{MDPI AG}},
title = {{{Development of a Tool Concept for Prestressed Fibre Metal Laminates and Their Effect on Interface Failure}}},
doi = {{10.3390/jcs8080316}},
volume = {{8}},
year = {{2024}},
}
@article{45782,
abstract = {{The development of automotive components with reduced greenhouse gas (GHG) emissions is needed to reduce overall vehicle emissions. Life Cycle Engineering (LCE) based on Life Cycle Assessment (LCA) supports this by providing holistic information and improvement potentials regarding eco-efficient products. Key factors influencing LCAs of automotive components, such as material production, will change in the future. First approaches for integrating future scenarios for these key factors into LCE already exist, but they only consider a limited number of parameters and scenarios. This work aims to develop a method that can be practically applied in the industry for integrating prospective LCAs (pLCA) into the LCE of automotive components, considering relevant parameters and consistent scenarios. Therefore, pLCA methods are further developed to investigate the influence of future scenarios on the GHG emissions of automotive components. The practical application is demonstrated for a vehicle component with different design options. This paper shows that different development paths of the foreground and background system can shift the ecological optimum of design alternatives. Therefore, future pathways of relevant parameters must be considered comprehensively to reduce GHG emissions of future vehicles. This work contributes to the methodological and practical integration of pLCA into automotive development processes and provides quantitative results.}},
author = {{Grenz, Julian and Ostermann, Moritz and Käsewieter, Karoline and Cerdas, Felipe and Marten, Thorsten and Herrmann, Christoph and Tröster, Thomas}},
issn = {{2071-1050}},
journal = {{Sustainability}},
keywords = {{prospective LCA, life cycle engineering (LCE), lightweight design, automotive components, body parts, circular economy, steel, aluminum, hybrid materials, fiber metal laminates}},
number = {{13}},
publisher = {{MDPI AG}},
title = {{{Integrating Prospective LCA in the Development of Automotive Components}}},
doi = {{10.3390/su151310041}},
volume = {{15}},
year = {{2023}},
}
@inproceedings{60302,
abstract = {{The combination of the mechanical properties of a clinched joint and of the material surrounding the joint determine the resulting properties of the component and joint. The cause and effect relationships between the joint and the joint environment offers the possibility of a specific modification through an adaptation in the design process. In order to identify these cause and effect relationships and resulting interactions experimentally, numerous of experiments are required. In this publication, a concept for the automated manufacturing of head tensile test and shear tensile test specimens – from cutting to clinching – by using a punch laser machine is presented. Based on a full-factorial experimental design, the parameters change of the properties of the joint environment by beading and change of the punch displacement are addressed. The influence on the properties of the clinched specimen is evaluated based on the variables Stiffness, force at the beginning of yielding and maximum force at head tensile loading and shear tensile loading. In addition, the geometric quality parameters of neck thickness, interlock and bottom thickness are evaluated. The relationships can be used to apply uniform loads to joints in joined structures to counteract oversizing.}},
author = {{Steinfelder, Christian and Brosius, Alexander}},
booktitle = {{Materials Research Proceedings}},
issn = {{2474-395X}},
keywords = {{Sheet Metal, Joining, Stiffness}},
location = {{Erlangen-Nürnberg}},
publisher = {{Materials Research Forum LLC}},
title = {{{Experimental investigation of the cause and effect relationships between the joint and the component during clinching}}},
doi = {{10.21741/9781644902417-19}},
volume = {{25}},
year = {{2023}},
}
@inproceedings{27652,
abstract = {{Aufgrund der Fortschritte der Digitalisierung finden Systeme zur Zustandsüberwachung vermehrt Einsatz in der Industrie, um durch eine zustandsbasierte oder eine prädiktive Instandhaltung Vorteile, wie eine verbesserte Zuverlässigkeit und geringere Kosten zu erzielen. Dabei beruhen Zustandsüberwachungssysteme auf den folgenden Bausteinen: Sensorik, Datenvorverarbeitung, Merkmalsextraktion und -auswahl, Diagnose bzw. Prognose sowie einer Entscheidungsfindung basierend auf den Ergebnissen. Jeder dieser Bausteine erfordert individuelle Einstellungen, um ein geeignetes Zustandsüberwachungssystem für die jeweilige Anwendung zu entwickeln. Eine offene Fragestellung im Bereich der Zustandsüberwachung ergibt sich aufgrund der Unsicherheit der Zukunft, die sich in den zukünftigen Betriebs- und Umgebungsbedingungen zeigt. Diese Unsicherheit gilt es in allen Bausteinen zu berücksichtigen.
Dieser Beitrag konzentriert sich auf den Baustein Merkmalsextraktion und -selektion, mit dem Ziel anhand geeigneter Merkmale eine Prognose der nutzbaren Restlebensdauer mit hoher Genauigkeit realisieren zu können. Daher werden geeignete Merkmale aus dem Zeitbereich und daraus abgeleitete Zustandsindikatoren für die Restlebensdauerprognose von technischen Systemen vorgestellt. Dabei sind Zustandsindikatoren Kenngrößen zur Beobachtung des Zustands der kritischen Systemkomponenten. Anhand dreier Anwendungsbeispiele wird ihre Eignung evaluiert. Dabei werden Daten aus Lebensdauerversuchen unter instationären Betriebs- und Umgebungsbedingungen ausgewertet. Die auftretenden Unsicherheiten der Zukunft werden somit berücksichtigt. Die Beispielsysteme beruhen auf Gummi-Metall-Elementen und Wälzlagern. Aus den generierten Ergebnissen lässt sich schließen, dass die Zustandsindikatoren aus der betrachteten Zeitreihen-Toolbox auch unter unbekannten Betriebs- und Umgebungsbedingungen robust sind.
}},
author = {{Aimiyekagbon, Osarenren Kennedy and Bender, Amelie and Sextro, Walter}},
booktitle = {{VDI-Berichte 2391}},
isbn = {{978-3-18-092391-8}},
issn = {{0083-5560 }},
keywords = {{run-to-failure, rubber-metal element, bearing prognostics, non-stationary operating conditions, varying operating conditions, feature extraction, feature selection}},
location = {{Würzburg}},
pages = {{197 -- 210}},
publisher = {{VDI Verlag GmbH}},
title = {{{Extraktion und Selektion geeigneter Merkmale für die Restlebensdauerprognose von technischen Systemen trotz aleatorischen Unsicherheiten }}},
year = {{2021}},
}
@article{25046,
abstract = {{While increasing digitalization enables multiple advantages for a reliable operation of technical systems, a remaining challenge in the context of condition monitoring is seen in suitable consideration of uncertainties affecting the monitored system. Therefore, a suitable prognostic approach to predict the remaining useful lifetime of complex technical systems is required. To handle different kinds of uncertainties, a novel Multi-Model-Particle Filtering-based prognostic approach is developed and evaluated by the use case of rubber-metal-elements. These elements are maintained preventively due to the strong influence of uncertainties on their behavior. In this paper, two measurement quantities are compared concerning their ability to establish a prediction of the remaining useful lifetime of the monitored elements and the influence of present uncertainties. Based on three performance indices, the results are evaluated. A comparison with predictions of a classical Particle Filter underlines the superiority of the developed Multi-Model-Particle Filter. Finally, the value of the developed method for enabling condition monitoring of technical systems related to uncertainties is given exemplary by a comparison between the preventive and the predictive maintenance strategy for the use case.}},
author = {{Bender, Amelie}},
issn = {{2075-1702}},
journal = {{Machines}},
keywords = {{prognostics, RUL predictions, particle filter, uncertainty consideration, Multi-Model-Particle Filter, model-based approach, rubber-metal-elements, predictive maintenance}},
number = {{10}},
title = {{{A Multi-Model-Particle Filtering-Based Prognostic Approach to Consider Uncertainties in RUL Predictions}}},
doi = {{10.3390/machines9100210}},
volume = {{9}},
year = {{2021}},
}
@inproceedings{21811,
abstract = {{In order to reduce the fuel consumption and consequently the greenhouse emissions, the automotive industry is implementing lightweight constructions in the body in white production. As a result, the use of aluminum alloys is continuously increasing. Due to poor weldability of aluminum in combination with other materials, mechanical joining technologies like clinching are increasingly used. In order to predict relevant characteristics of clinched joints and to ensure the reliability of the process, it is simulated numerically during product development processes. In this regard the predictive accuracy of the simulated process highly depends on the implemented friction model. In particular, the frictional behavior between the sheet metals affects the geometrical formation of the clinched joint significantly. This paper presents a testing method, which enables to determine the frictional coefficients between sheet metal materials for the simulation of clinching processes. For this purpose, the correlation of interface pressure and the relative velocity between aluminum sheets in clinching processes is investigated using numerical simulation. Furthermore, the developed testing method focuses on the specimen geometry as well as the reproduction of the occurring friction conditions between two sheet metal materials in clinching processes. Based on a methodical approach the test setup is explained and the functionality of the method is proven by experimental tests using sheet metal material EN AW6014. }},
author = {{Rossel, Moritz Sebastian and Böhnke, Max and Bielak, Christian Roman and Bobbert, Mathias and Meschut, Gerson}},
booktitle = {{Sheet Metal 2021}},
keywords = {{Tribology, Sheet Metal, Simulation}},
pages = {{81--88}},
publisher = {{Trans Tech Publications Ltd}},
title = {{{Development of a Method for the Identification of Friction Coefficients in Sheet Metal Materials for the Numerical Simulation of Clinching Processes}}},
doi = {{10.4028/www.scientific.net/KEM.883.81}},
volume = {{883}},
year = {{2021}},
}
@article{64019,
abstract = {{A chiral zirconium-based catalyst, DUT-67-Pro containing 8-connected Zr6-clusters is obtained by post synthetic functionalization of Zr6O6(OH)2(TDC)4(HCOO)2 (DUT-67, TDC = 2,5-thiophenedicarboxylate) with the chiral monocarboxylic acid, L-proline. 13C and 15N solid state MAS and DNP NMR studies of DUT-67-Pro confirm the integration of L-proline into the porous framework. The chiral MOF catalyst exhibits an excellent catalytic activity at low temperature (298 K) with an unprecedented syn-(S,S)-product selectivity in an asymmetric aldol addition reaction of cyclohexanone to 4-nitrobenzaldehyde (yield = 95%, ee = 96%). Comparative catalytic studies using a molecular Zr6-cluster model compound indicate the Zr6-moiety to be responsible for this inverse diastereoselectivity compared to well-established L-proline organocatalysis and a mechanism is proposed to explain the Zr6-cluster-mediated syn-selectivity. Masking residual acidic active sites in the cluster of the framework was found to be a key prerequisite to achieve the high enantioselectivity. The purely heterogeneous catalytic system based on DUT-67-Pro is highly stable and can be recycled several times.}},
author = {{Nguyen, Khoa D. and Kutzscher, Christel and Ehrling, Sebastian and Senkovska, Irena and Bon, Volodymyr and Oliveira, Marcos and Gutmann, Torsten and Buntkowsky, Gerd and Kaskel, Stefan}},
journal = {{Journal of Catalysis}},
keywords = {{-proline, -selective aldol reaction, Chirality, Metal-organic framework, Zirconium}},
pages = {{41–50}},
title = {{{Insights into the role of zirconium in proline functionalized metal-organic frameworks attaining high enantio- and diastereoselectivity}}},
doi = {{10.1016/j.jcat.2019.07.003}},
volume = {{377}},
year = {{2019}},
}
@article{63991,
abstract = {{A series of 1 and 2 nm sized platinum nanoparticles (Pt-NPs) deposited on different support materials, namely, gamma-alumina (gamma-Al2O3), titanium dioxide (TiO2), silicon dioxide (SiO2) and fumed silica are investigated by solid-state NMR and dynamic nuclear polarization enhanced NMR spectroscopy (DNP). DNP signal enhancement factors up to 170 enable gaining deeper insight into the surface chemistry of Pt-NPs. Carbon monoxide is used as a probe molecule to analyze the adsorption process and the surface chemistry on the supported Pt-NPs. The studied systems show significant catalytic activity in carbon monoxide oxidation on their surface at room temperature. The underlying catalytic mechanism is the water-gas shift reaction. In the case of alumina as the support the produced CO2 reacts with the surface to form carbonate, which is revealed by solid-state NMR. A similar carbonate formation is also observed when physical mixtures of neat alumina with silica, fumed silica and titania supported Pt-NPs are studied.}},
author = {{Klimavicius, V. and Neumann, S. and Kunz, S. and Gutmann, Torsten and Buntkowsky, G.}},
issn = {{2044-4753}},
journal = {{Catalysis Science & Technology}},
keywords = {{Chemistry, gamma-alumina, hydrogenation, silica, c-13, interactions, metal-catalysts, particle-size, platinum nanoparticles, sites, surface, water-gas shift}},
number = {{14}},
pages = {{3743–3752}},
title = {{{Room temperature CO oxidation catalysed by supported Pt nanoparticles revealed by solid-state NMR and DNP spectroscopy}}},
doi = {{10.1039/c9cy00684b}},
volume = {{9}},
year = {{2019}},
}
@article{64010,
abstract = {{Seven novel dirhodium coordination polymers (Rh-2-Ln) (n = 1-7) are prepared by employing bitopic ligands to connect dirhodium nodes. The formation of the framework is confirmed by attenuated total reflectance Fourier transform infrared (ATR-FTIR) and H-1 C-13 cross polarization magic angle spinning nuclear magnetic resonance (CP MAS NMR) spectroscopy. Defect sites resulting from incomplete ligand substitution are revealed by F-19 MAS NMR. The random stacking behavior of the frameworks in the obtained solid is analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The Rh-2/O interaction in neighboring layers is investigated by diffuse reflectance ultra-violet visible light (DR-UV-vis) spectroscopy and X-ray photoelectron spectroscopy (XPS). This interaction is relevant to understand the catalytic behavior of various Rh-2-Ln catalysts in the cyclopropanation of styrene with ethyl diazoacetate (EDA). In this context, the structure-reactivity relationship is discussed by taking into consideration both interlayer Rh-2/O interactions and steric effects of side chains.}},
author = {{Liu, J. Q. and Xu, Y. P. and Groszewicz, P. B. and Brodrecht, M. and Fasel, C. and Hofmann, K. and Tan, X. J. and Gutmann, Torsten and Buntkowsky, G.}},
issn = {{2044-4753}},
journal = {{Catalysis Science & Technology}},
keywords = {{Chemistry, asymmetric cyclopropanation, c-h insertion, carbene transformations, carboxylates, catalysts, functionalization, immobilization, metal-organic frameworks, nmr, solid support}},
number = {{20}},
pages = {{5190–5200}},
title = {{{Novel dirhodium coordination polymers: the impact of side chains on cyclopropanation}}},
doi = {{10.1039/c8cy01493k}},
volume = {{8}},
year = {{2018}},
}
@article{62809,
abstract = {{Superhierarchically rough films are rapidly synthesised on metal substrates via electrochemically triggered self-assembly of meso/macroporous-structured metal-organic framework (MOF) crystals. These coatings are applied to immobilise a functional oil with low surface energy to provide stable coatings repellent to a wide range of hydrophobic as well as hydrophilic fluids. Such omniphobic surfaces are highly interesting for several applications such as anti-fouling, anti-icing, and dropwise condensation, and become easily scalable with the presented bottom-up fabrication approach. As investigated by environmental scanning electron microscopy (ESEM), the presented perfluorinated oil-infused Cu-BTC coating constitutes of a flat liquid-covered surface with protruding edges of octahedral superstructured MOF crystals. Water and non-polar diiodomethane droplets form considerably high contact angles and even low-surface-tension fluids, e.g. acetone, form droplets on the infused coating. The repellent properties towards the test fluids do not change upon extended water spraying in contrast to oil-infused porous copper oxide or native copper surfaces. It is discussed in detail, how the presented electrodeposited MOF films grow and provide a proficient surface morphology to stabilise the functional oil film due to hemiwicking.}},
author = {{Sablowski, Jakob and Linnemann, Julia and Hempel, Simone and Hoffmann, Volker and Unz, Simon and Beckmann, Michael and Giebeler, Lars}},
issn = {{2045-2322}},
journal = {{Scientific Reports}},
keywords = {{electrodeposition, metal-organic framework, MOF, drop-wise condensation, omniphobic coatings}},
number = {{1}},
publisher = {{Springer Science and Business Media LLC}},
title = {{{Electrodeposited metal-organic framework films as self-assembled hierarchically superstructured supports for stable omniphobic surface coatings}}},
doi = {{10.1038/s41598-018-33542-4}},
volume = {{8}},
year = {{2018}},
}
@article{62807,
abstract = {{The thermolysis of electrodeposited metal–organic framework (MOF) films represents a novel approach to build supercapacitor electrodes of already electrically contacted MOF-derived high-performance metal oxide/carbon materials which are also highly interesting for other applications. MOFs are widely utilised as precursors to synthesise functional materials by thermal decomposition (pyrolysis, carbonisation). Using electrochemically coated MOF precursor films instead of powder greatly simplifies the processing of such materials and potentially enhances the resulting active materials' performance. In the case of electrochemical energy storage electrodes, the coated substrate later functions as current collector which is well-attached to the active material without the need for any additives. This close connection decreases electron transfer resistances and saves multiple steps of powder formulation and coating. Films of a metal–organic framework based on 1,3,5-benzene-tricarboxylate (BTC) and cobalt(II) cations were electrochemically coated on cobalt foils which act as the Co2+ cation source. Manganese films were electrodeposited and subsequently partly redissolved in a linker-containing electrolyte to achieve Mn/Mn–BTC bilayered films on stainless steel. This procedure extends the method for any kind of current collector material. The films were thermolysed to gain nanostructured metal oxide spinel (Me3O4)/carbon hybrid electrodes. Investigations of the electrochemical properties in regard to supercapacitor applications show that Co3O4/C films exhibit pseudocapacitance and that Mn3O4/C films are suitable for redox electrodes with high-rate capability operating in a wide potential range in aqueous electrolytes. Co–BTC powder was also thermally treated yielding cobalt particles embedded in a graphitic carbon matrix. The pseudocapacitive properties of conventionally coated films of this powder material are limited.}},
author = {{Linnemann, Julia and Taudien, Laura and Klose, Markus and Giebeler, Lars}},
issn = {{2050-7488}},
journal = {{Journal of Materials Chemistry A}},
keywords = {{electrodeposition, metal-organic framework, MOF, supercapacitors}},
number = {{35}},
pages = {{18420--18428}},
publisher = {{Royal Society of Chemistry (RSC)}},
title = {{{Electrodeposited films to MOF-derived electrochemical energy storage electrodes: a concept of simplified additive-free electrode processing for self-standing, ready-to-use materials}}},
doi = {{10.1039/c7ta01874f}},
volume = {{5}},
year = {{2017}},
}
@inproceedings{9887,
abstract = {{A model to calculate the locally resolved tangential contact forces of the wheel rail contact with respect to contact kinematics, material and surface properties as well as temperature is introduced. The elasticity of wheel and rail is modeled as an elastic layer consisting of point contact elements connected by springs to each other and to the wheel. Each element has two degrees of freedom in tangential directions. The resulting total stiffness matrix is reduced to calculate only the position of the elements in contact. Friction forces as well as contact stiffnesses are incorporated by a nonlinear force-displacement characteristic, which originates from a detailed contact model. The contact elements are transported through the contact zone in discrete time steps. After each time step an equilibrium is calculated. For all elements, their temperature and its influence on local friction are regarded by calculating friction power and temperature each time step.}},
author = {{Neuhaus, Jan and Sextro, Walter}},
booktitle = {{Proceedings of the 5th International Conference on Computational Methods}},
editor = {{Liu, G.R. and Guan, Z.W.}},
keywords = {{Rolling Contact, Discrete Elements, Contact Stiffness, Temperature}},
publisher = {{ScienTech Publisher}},
title = {{{Thermo-Mechanical Model for Wheel Rail Contact using Coupled Point Contact Elements}}},
year = {{2014}},
}