@article{40512, author = {{Hüsing, Sven and Weiser, Niklas and Biehler, Rolf}}, journal = {{mathematik lehren}}, number = {{228}}, pages = {{23–27}}, publisher = {{Friedrich Verlag}}, title = {{{Faszination 3D-Film: Entwicklung einer 3D-Konstruktion}}}, volume = {{2021}}, year = {{2021}}, } @article{41011, abstract = {{The controlled assembly of well-defined planar nanoclusters from molecular precursors is synthetically challenging and often plagued by the predominant formation of 3D-structures and nanoparticles. Herein, we report planar iron hydride nanoclusters from reactions of main group element hydrides with iron(II) bis(hexamethyldisilazide). The structures and properties of isolated Fe4, Fe6, and Fe7 nanoplatelets and calculated intermediates enable an unprecedented insight into the underlying building principle and growth mechanism of iron clusters, metal monolayers, and nanoparticles.}}, author = {{Chakraborty, Uttam and Bügel, Patrick and Fritsch, Lorena and Weigend, Florian and Bauer, Matthias and Jacobi von Wangelin, Axel}}, issn = {{2191-1363}}, journal = {{ChemistryOpen}}, keywords = {{General Chemistry}}, number = {{2}}, pages = {{265--271}}, publisher = {{Wiley}}, title = {{{Planar Iron Hydride Nanoclusters: Combined Spectroscopic and Theoretical Insights into Structures and Building Principles}}}, doi = {{10.1002/open.202000307}}, volume = {{10}}, year = {{2021}}, } @article{30119, abstract = {{Abstract Background Subjective Memory Complaints (SMC) in elderly people due to preclinical Alzheimer’s Disease may be associated with dysregulation of the Kynurenine Pathway (KP), with an increase in neurotoxic metabolites that affect cognition. Golf is a challenging sport with high demands on motor, sensory, and cognitive abilities, which might bear the potential to attenuate the pathological changes of preclinical AD. This trial investigated the feasibility of learning to play golf for elderly with cognitive problems and its effects on cognitive functions and the KP. Methods In a 22-week single-blinded randomized controlled trial, elderly people with SMC were allocated to the golf (n = 25, 180 min training/week) or control group (n = 21). Primary outcomes were feasibility (golf exam, adherence, adverse events) and general cognitive function (Alzheimer’s Disease Assessment Scale). Secondary outcomes include specific cognitive functions (Response Inhibition, Corsi Block Tapping Test, Trail Making Test), KP metabolites and physical performance (6-Minute-Walk-Test). Baseline-adjusted Analysis-of-Covariance was conducted for each outcome. Results 42 participants were analyzed. All participants that underwent the golf exam after the intervention passed it (20/23). Attendance rate of the golf intervention was 75 %. No adverse events or drop-outs related to the intervention occurred. A significant time*group interaction (p = 0.012, F = 7.050, Cohen’s d = 0.89) was found for correct responses on the Response Inhibition task, but not for ADAS-Cog. Moreover, a significant time*group interaction for Quinolinic acid to Tryptophan ratios (p = 0.022, F = 5.769, Cohen’s d = 0.84) in favor of the golf group was observed. An uncorrected negative correlation between attendance rate and delta Quinolinic acid to Kynurenic acid ratios in the golf group (p = 0.039, r=-0.443) was found as well. Conclusions The findings indicate that learning golf is feasible and safe for elderly people with cognitive problems. Preliminary results suggest positive effects on attention and the KP. To explore the whole potential of golfing and its effect on cognitive decline, a larger cohort should be studied over a longer period with higher cardiovascular demands. Trial registration The trial was retrospectively registered (2nd July 2018) at the German Clinical Trials Register (DRKS00014921). }}, author = {{Stroehlein, Julia K. and Vieluf, Solveig and Zimmer, Philipp and Schenk, Alexander and Oberste, Max and Gölz, Christian Johannes and van den Bongard, Franziska and Reinsberger, Claus}}, issn = {{1471-2377}}, journal = {{BMC Neurology}}, keywords = {{Clinical Neurology, General Medicine}}, number = {{1}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Learning to play golf for elderly people with subjective memory complaints: feasibility of a single‐blinded randomized pilot trial}}}, doi = {{10.1186/s12883-021-02186-9}}, volume = {{21}}, year = {{2021}}, } @article{41818, author = {{Hense, Dominik and Büngeler, Anne and Kollmann, Fabian and Hanke, Marcel and Orive, Alejandro and Keller, Adrian and Grundmeier, Guido and Huber, Klaus and Strube, Oliver I.}}, issn = {{1525-7797}}, journal = {{Biomacromolecules}}, keywords = {{Materials Chemistry, Polymers and Plastics, Biomaterials, Bioengineering}}, number = {{10}}, pages = {{4084--4094}}, publisher = {{American Chemical Society (ACS)}}, title = {{{Self-Assembled Fibrinogen Hydro- and Aerogels with Fibrin-like 3D Structures}}}, doi = {{10.1021/acs.biomac.1c00489}}, volume = {{22}}, year = {{2021}}, } @article{41909, abstract = {{The continuous development of medical methods in recent decades has achieved measurable improvement. The interdisciplinary cooperation of engineers and physicians is a forward-looking component of this development. However, this cooperation also results in new interfaces on the communication and software level, which must be defined by implementing a systematic workflow. In this paper, the step-by-step implementation of engineering methods into the surgical workflow is shown. The focus is on the basic requirements and the necessary exchange of information. Additively manufactured models for preoperative elucidation of the patient are used as a psychological added value to increase the transparency of the surgical procedure. In addition, the models serve to train young surgeons and provide the opportunity to plan advanced surgical techniques.}}, author = {{Risse, Lena and Kullmer, Gunter}}, issn = {{2059-4755}}, journal = {{Journal of 3D Printing in Medicine}}, keywords = {{General Medicine}}, number = {{2}}, pages = {{111--121}}, publisher = {{Future Medicine Ltd}}, title = {{{Application of engineering methods in the planning process of surgical treatments}}}, doi = {{10.2217/3dp-2020-0020}}, volume = {{5}}, year = {{2021}}, } @inproceedings{39401, author = {{Lange, Sven and Hedayat, Christian and Kuhn, Harald and Hilleringmann, Ulrich}}, booktitle = {{2021 Smart Systems Integration (SSI)}}, publisher = {{IEEE}}, title = {{{Adaptation and Optimization of Planar Coils for a More Accurate and Far-Reaching Magnetic Field-Based Localization in the Near Field}}}, doi = {{10.1109/ssi52265.2021.9466958}}, year = {{2021}}, } @article{21946, abstract = {{Lithium niobate (LiNbO3), a material frequently used in optical applications, hosts different kinds of polarons that significantly affect many of its physical properties. In this study, a variety of electron polarons, namely free, bound, and bipolarons, are analyzed using first-principles calculations. We perform a full structural optimization based on density-functional theory for selected intrinsic defects with special attention to the role of symmetry-breaking distortions that lower the total energy. The cations hosting the various polarons relax to a different degree, with a larger relaxation corresponding to a larger gap between the defect level and the conduction-band edge. The projected density of states reveals that the polaron states are formerly empty Nb 4d states lowered into the band gap. Optical absorption spectra are derived within the independent-particle approximation, corrected by the GW approximation that yields a wider band gap and by including excitonic effects within the Bethe-Salpeter equation. Comparing the calculated spectra with the density of states, we find that the defect peak observed in the optical absorption stems from transitions between the defect level and a continuum of empty Nb 4d states. Signatures of polarons are further analyzed in the reflectivity and other experimentally measurable optical coefficients.}}, author = {{Schmidt, Falko and Kozub, Agnieszka L. and Gerstmann, Uwe and Schmidt, Wolf Gero and Schindlmayr, Arno}}, issn = {{2073-4352}}, journal = {{Crystals}}, pages = {{542}}, publisher = {{MDPI}}, title = {{{Electron polarons in lithium niobate: Charge localization, lattice deformation, and optical response}}}, doi = {{10.3390/cryst11050542}}, volume = {{11}}, year = {{2021}}, } @article{32434, abstract = {{Whereas initial findings have already identified cortical patterns accompanying proprioceptive deficiencies in patients after anterior cruciate ligament reconstruction (ACLR), little is known about compensatory sensorimotor mechanisms for re-establishing postural control. Therefore, the aim of the present study was to explore leg dependent patterns of cortical contributions to postural control in patients 6 weeks following ACLR. A total of 12 patients after ACLR (25.1 ± 3.2 years, 178.1 ± 9.7 cm, 77.5 ± 14.4 kg) and another 12 gender, age, and activity matched healthy controls participated in this study. All subjects performed 10 × 30 s. single leg stances on each leg, equipped with 64-channel mobile electroencephalography (EEG). Postural stability was quantified by area of sway and sway velocity. Estimations of the weighted phase lag index were conducted as a cortical measure of functional connectivity. The findings showed significant group × leg interactions for increased functional connectivity in the anterior cruciate ligament (ACL) injured leg, predominantly including fronto−parietal [F(1, 22) = 8.41, p ≤ 0.008, η2 = 0.28], fronto−occipital [F(1, 22) = 4.43, p ≤ 0.047, η2 = 0.17], parieto−motor [F(1, 22) = 10.30, p ≤ 0.004, η2 = 0.32], occipito−motor [F(1, 22) = 5.21, p ≤ 0.032, η2 = 0.19], and occipito−parietal [F(1, 22) = 4.60, p ≤ 0.043, η2 = 0.17] intra−hemispherical connections in the contralateral hemisphere and occipito−motor [F(1, 22) = 7.33, p ≤ 0.013, η2 = 0.25] on the ipsilateral hemisphere to the injured leg. Higher functional connectivity in patients after ACLR, attained by increased emphasis of functional connections incorporating the somatosensory and visual areas, may serve as a compensatory mechanism to control postural stability of the injured leg in the early phase of rehabilitation. These preliminary results may help to develop new neurophysiological assessments for detecting functional deficiencies after ACLR in the future.}}, author = {{Lehmann, Tim and Büchel, Daniel and Mouton, Caroline and Gokeler, Alli and Seil, Romain and Baumeister, Jochen}}, issn = {{1662-5161}}, journal = {{Frontiers in Human Neuroscience}}, keywords = {{Behavioral Neuroscience, Biological Psychiatry, Psychiatry and Mental health, Neurology, Neuropsychology and Physiological Psychology}}, publisher = {{Frontiers Media SA}}, title = {{{Functional Cortical Connectivity Related to Postural Control in Patients Six Weeks After Anterior Cruciate Ligament Reconstruction}}}, doi = {{10.3389/fnhum.2021.655116}}, volume = {{15}}, year = {{2021}}, } @inbook{22766, author = {{Dahms, Frederik and Homberg, Werner}}, booktitle = {{Forming the Future}}, issn = {{2367-1181}}, location = {{Ohio, USA, VIRTUAL EVENT}}, pages = {{2249--2259}}, publisher = {{Springer, Cham}}, title = {{{Investigations and Improvements in 3D-DIC Optical Residual Stress Analysis—A New Temperature Compensation Method}}}, doi = {{10.1007/978-3-030-75381-8_189}}, year = {{2021}}, } @article{24541, abstract = {{The mechanical properties of joined structures are determined considerably by the chosen joining technology. With the aim of providing a method that enables a faster and more profound decision-making in the spatial distribution of joining points during product development, a new method for the load path analysis of joining points is presented. For an exemplary car body, the load type in the joining elements, i.e. pure tensile, shear and combined tensile-shear loads, is determined using finite element analysis (FEA). Based on the evaluated loads, the resulting load paths in selected joining points are analyzed using a 2D FE-model of a clinching point. State of the art methods for load path analysis are dependent on the selected coordinate system or the existing stress state. Thus, a general statement about the load transmission path is not possible at this time. Here, a novel method for the analysis of load paths is used, which is independent of the alignment of the analyzed geometry. The basic assumption of the new load path analysis method was confirmed by using a simple specimen with a square hole in different orientations. The results presented here show a possibility to display the load transmission path invariantly. In further steps, the method will be extended for 3D analysis and the investigation of more complex assemblies. The primary goal of this methodical approach is an even load distribution over the joining elements and the component. This will provide a basis for future design approaches aimed at reducing the number of joining elements in joined structures.}}, author = {{Steinfelder, Christian and Martin, Sven and Brosius, Alexander and Tröster, Thomas}}, issn = {{1662-9795}}, journal = {{Key Engineering Materials}}, pages = {{73--80}}, title = {{{Load Path Transmission in Joining Elements}}}, doi = {{10.4028/www.scientific.net/kem.883.73}}, year = {{2021}}, } @inbook{44526, author = {{Tecklenburg, Feline}}, booktitle = {{Dass die Welt wohnlich für alle wird. Klartexte, Anfragen, Perspektiven. Ina Praetorius zum 65. Geburtstag}}, editor = {{Fehle, Hans Jörg and Langenbacher, Andrea}}, publisher = {{Matthias-Grünewald-Verlag}}, title = {{{Wirtschaft ist Care ist radikale Demokratie}}}, year = {{2021}}, } @inproceedings{24080, abstract = {{Challenges of the development of mechatronic systems and corresponding production systems have increased steadily. Changes are primarily due to increased product complexity and the connection to the internet of things and services, enabling Cyber-Physical Systems (CPS) and Cyber-Physical Production Systems (CPPS). Major innovations of the revised VDI guideline 2206 for developing mechatronic systems are systems thinking as a core element and six checkpoints for structuring deliverables along the V-Model. These checkpoints serve for orientation in result progress and thus enable a structured and complete development process. However, tasks and checkpoints of the new guideline focus on the product development itself without integrating the development of related CPPS, enabling optimization simultaneously to system development. Implications are derived by a three-step analysis. The paper at hand contributes fundamental extensions of the checkpoint questions regarding integrated CPPS development. These questions provide methodical support for system developers of CPPS for CPS by enabling the project manager to check the status, schedule further development steps and evaluate the maturity of the whole, integrated development.}}, author = {{Gräßler, Iris and Wiechel, Dominik and Roesmann, Daniel and Thiele, Henrik}}, booktitle = {{Procedia CIRP}}, issn = {{2212-8271}}, keywords = {{Cyber-Physical Production System (CPPS), V-Model, Product System Development, Integrated Development, VDI 2206}}, pages = {{253--258}}, title = {{{V-model based development of cyber-physical systems and cyber-physical production systems}}}, doi = {{10.1016/j.procir.2021.05.119}}, year = {{2021}}, } @inproceedings{24281, abstract = {{In order to optimize production processes and to avoid errors, it is not only necessary to automate processes, but also to integrate workers with their individual personality and skill profiles. For this purpose, human factors should be considered in the entire design process. The integrated view of mental human models, the cognitive demand of the working environment and the automation design is essential. Human-System Integration (HSI) constitutes a promising approach. Current model-based approaches offer possibilities to analyze and optimize tasks within an overall system, but they still lack integration. This leads to the research question: How can human factors be integrated into a system model of a socio-technical, Cyber-Physical Production System? The paper at hand contributes an approach of human factor integration into the procedure of Model-Based Systems Engineering for Cyber-Physical Production Systems (CPPS). The approach combines a system model of a CPPS with HSI concepts. In accordance to the benefits of MBSE, SysML is selected to integrate human factors in the development process of a CPPS. The approach is divided into five steps, which includes the extension of the SysML meta model. This allows the optimization of skill-based human-machine interaction. Defined HSI-Profiles enable system developers to integrate employee requirements at early stages within the development process. The approach is demonstrated by the maintenance of a 3D-Printer as a case example. This research enables system developers to depict individual workers with the help of the developed concepts and systematically integrate them into the development process of a CPPS.}}, author = {{Gräßler, Iris and Wiechel, Dominik and Roesmann, Daniel}}, booktitle = {{Procedia CIRP}}, issn = {{2212-8271}}, pages = {{518--523}}, title = {{{Integrating human factors in the model based development of cyber-physical production systems}}}, doi = {{10.1016/j.procir.2021.05.113}}, year = {{2021}}, } @article{45640, abstract = {{I study a dynamic variant of the Dixit–Stiglitz (Am Econ Rev 67(3), 1977) model of monopolistic competition by introducing price stickiness à la Fershtman and Kamien (Econometrica 55(5), 1987). The analysis is restricted to bounded quantity and price paths that fulfill the necessary conditions for an open-loop Nash equilibrium. I show that there exists a symmetric steady state and that its stability depends on the degree of product differentiation. When moving from complements to perfect substitutes, the steady state is either a locally asymptotically unstable (spiral) source, a stable (spiral) sink or a saddle point. I further apply the Hopf bifurcation theorem and prove the existence of limit cycles, when passing from a stable to an unstable steady state. Lastly, I provide a numerical example and show that there exists a stable limit cycle.}}, author = {{Hoof, Simon}}, issn = {{1573-2878}}, journal = {{Journal of Optimization Theory and Applications}}, number = {{2}}, publisher = {{Springer}}, title = {{{Dynamic Monopolistic Competition}}}, volume = {{189}}, year = {{2021}}, } @article{46078, abstract = {{Abstract Aim To identify and summarize the evidence for the effect of health-oriented leadership interventions on health and well-being outcomes at the employee level following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement (Moher et al. 2009). Subject and Methods A systematic search of relevant studies was conducted in multiple databases. Randomized controlled trials (RCTs), cluster-randomized controlled trials (cRCTs) and controlled before–after studies (CBAs) were included based on the following criteria: interventions that addressed supervisors, to raise awareness for the importance of health issues, teach mindfulness practices for conscious awareness, reduce stress and promote resources at the level of individual behavior, and evaluated the effect on at least one outcome of psychomental stress, absenteeism and well-being on the employee level. Results Of 6126 publications retrieved, ten studies were identified for analysis. Significant effects of leadership training were reported on exhaustion tendency, self-reported sickness absence, work-related sickness absence and job satisfaction in studies comparing health-oriented training programs to no intervention. Studies comparing health-oriented leadership training to other training did not report significant effects. Risk of bias was judged to be high in seven studies and unclear in three studies. Conclusion Evidence for the effectiveness of health-oriented leadership interventions on employees’ stress, absenteeism or well-being is judged to be low, clearly indicating the need for more and higher-quality research. }}, author = {{Dannheim, Indra and Ludwig-Walz, Helena and Buyken, Anette and Grimm, Valerie and Kroke, Anja}}, issn = {{2198-1833}}, journal = {{Journal of Public Health}}, keywords = {{Public Health, Environmental and Occupational Health}}, number = {{12}}, pages = {{2777--2789}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Effectiveness of health-oriented leadership interventions for improving health and wellbeing of employees: a systematic review}}}, doi = {{10.1007/s10389-021-01664-1}}, volume = {{30}}, year = {{2021}}, } @article{21436, abstract = {{Ultrasonic wire bonding is a solid-state joining process, used in the electronics industry to form electrical connections, e.g. to connect electrical terminals within semiconductor modules. Many process parameters affect the bond strength, such like the bond normal force, ultrasonic power, wire material and bonding frequency. Today, process design, development, and optimization is most likely based on the knowledge of process engineers and is mainly performed by experimental testing. In this contribution, a newly developed simulation tool is presented, to reduce time and costs and efficiently determine optimized process parameter. Based on a co-simulation of MATLAB and ANSYS, the different physical phenomena of the wire bonding process are considered using finite element simulation for the complex plastic deformation of the wire and reduced order models for the transient dynamics of the transducer, wire, substrate and bond formation. The model parameters such as the coefficients of friction between bond tool and wire and between wire and substrate were determined for aluminium and copper wire in experiments with a test rig specially developed for the requirements of heavy wire bonding. To reduce simulation time, for the finite element simulation a restart analysis and high performance computing is utilized. Detailed analysis of the bond formation showed, that the normal pressure distribution in the contact between wire and substrate has high impact on bond formation and distribution of welded areas in the contact area.}}, author = {{Schemmel, Reinhard and Krieger, Viktor and Hemsel, Tobias and Sextro, Walter}}, issn = {{0026-2714}}, journal = {{Microelectronics Reliability}}, keywords = {{Ultrasonic heavy wire bonding, Co-simulation, ANSYS, MATLAB, Process optimization, Friction coefficient, Copper-copper, Aluminium-copper}}, pages = {{114077}}, title = {{{Co-simulation of MATLAB and ANSYS for ultrasonic wire bonding process optimization}}}, doi = {{https://doi.org/10.1016/j.microrel.2021.114077}}, volume = {{119}}, year = {{2021}}, } @inbook{29936, author = {{Ramaswami, Arjun and Kenter, Tobias and Kühne, Thomas and Plessl, Christian}}, booktitle = {{Applied Reconfigurable Computing. Architectures, Tools, and Applications}}, isbn = {{9783030790240}}, issn = {{0302-9743}}, publisher = {{Springer International Publishing}}, title = {{{Evaluating the Design Space for Offloading 3D FFT Calculations to an FPGA for High-Performance Computing}}}, doi = {{10.1007/978-3-030-79025-7_21}}, year = {{2021}}, } @article{37547, author = {{Vochatzer, Stefanie and Engelmann , Sebastian }}, journal = {{Journal der Schreibwissenschaft}}, number = {{22}}, pages = {{52--63}}, publisher = {{WBV}}, title = {{{ Autoethnografie und Kreatives Schreiben}}}, doi = {{10.3278/JOS2102W052}}, volume = {{3}}, year = {{2021}}, } @article{51202, abstract = {{When joining lightweight parts of various materials, clinching is a cost efficient solution. In a production line, the quality of a clinch point is primarily controlled by measurement of dimensions, which are accessible from outside. However, methods such as visual testing and measuring the bottom thickness as well as the outer diameter are not able to deliver any information about the most significant geometrical characteristic of the clinch point, neck thickness and undercut. Furthermore, ex-situ destructive methods such as microsectioning cannot detect elastic deformations and cracks that close after unloading. In order to exceed the current limits, a new non-destructive in-situ testing method for the clinching process is necessary. This work proposes a concept to characterize clinch points in-situ by combining two complementary non-destructive methods, namely, computed tomography (CT) and ultrasonic testing. Firstly, clinch points with different geometrical characteristics are analysed experimentally using ex-situ CT to get a highly spatially resolved 3D-image of the object. In this context, highly X-ray attenuating materials enhancing the visibility of the sheet-sheet interface are investigated. Secondly, the test specimens are modelled using finite element method (FEM) and a transient dynamic analysis (TDA) is conducted to study the effect of the geometrical differences on the deformation energy and to qualify the TDA as a fast in-situ non-destructive method for characterizing clinch points at high temporal resolution.}}, author = {{Köhler, Daniel and Sadeghian, Behdad and Kupfer, Robert and Troschitz, Juliane and Gude, Maik and Brosius, Alexander}}, issn = {{1662-9795}}, journal = {{Key Engineering Materials}}, keywords = {{Mechanical Engineering, Mechanics of Materials, General Materials Science}}, pages = {{89--96}}, publisher = {{Trans Tech Publications, Ltd.}}, title = {{{A Method for Characterization of Geometric Deviations in Clinch Points with Computed Tomography and Transient Dynamic Analysis}}}, doi = {{10.4028/www.scientific.net/kem.883.89}}, volume = {{883}}, year = {{2021}}, } @inproceedings{24159, abstract = {{The online fitting of a microscopic traffic simulation model to reconstruct the current state of a real traffic area can be challenging depending on the provided data. This paper presents a novel method based on limited data from sensors positioned at specific locations and guarantees a general accordance of reality and simulation in terms of multimodal road traffic counts and vehicle speeds. In these considerations, the actual purpose of research is of particular importance. Here, the research aims at improving the traffic flow by controlling the Traffic Light Systems (TLS) of the examined area which is why the current traffic state and the route choices of individual road users are the matter of interest. An integer optimization problem is derived to fit the current simulation to the latest field measurements. The concept can be transferred to any road traffic network and results in an observation of the current multimodal traffic state matching at the given sensor position. First case studies show promosing results in terms of deviations between reality and simulation.}}, author = {{Malena, Kevin and Link, Christopher and Mertin, Sven and Gausemeier, Sandra and Trächtler, Ansgar}}, booktitle = {{VEHITS 2021 Proceedings of the 7th International Conference on Vehicle Technology and Intelligent Transport Systems}}, isbn = {{978-989-758-513-5}}, keywords = {{Microscopic Traffic Simulation, Online State Estimation, Mixed Road Users, Sensor Fusion, Integer Programming, Route Choice, Vehicle2Infrastructure}}, location = {{Online Streaming}}, pages = {{386--395}}, publisher = {{SCITEPRESS}}, title = {{{Online State Estimation for Microscopic Traffic Simulations using Multiple Data Sources*}}}, volume = {{7}}, year = {{2021}}, }