Reactive die bonding on LTCC substrates - analysis by CFD simulation. - In: 2023 24th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE), (2023), insges. 5 S.
To improve the understanding of reactive multilayer systems as a joining process computational fluid dynamics (CFD) simulations have been performed and compared with experimental measurements made using a pyrometer. These CFD simulations consist of a shoebox model which contains different layers. The layers in the model are an Ni/Al reactive multilayer, low temperature co-fired ceramic (LTCC) substrate and the surrounding air environment. To simulate the heat released by the multilayer system, a user defined function of probability density function (PDF) form was written for the heat source. The peak energy intensity, reaction width and reaction speed can be controlled via the PDF to adapt the simulation to the real model.
https://doi.org/10.1109/EuroSimE56861.2023.10100772
Vascular MPI: visualization and tracking of rapidly moving samples. - In: International journal on magnetic particle imaging, ISSN 2365-9033, Bd. 9 (2023), 1, 2303044, S. 1-3
Magnetic Particle Imaging (MPI) is a fast imaging technique for the visualization of the distribution of superparamagnetic iron-oxide nanoparticles (SPIONs) in 3D. For spatial encoding, a field free area is moved rapidly through the field of view (FOV) generating a localized signal. Fast moving samples, e.g., a bolus of SPIONs traveling through the large veins in the human body carried by blood flow with velocities in the order of ˜45 cm/s and higher, cause temporal blurring in MPI measurements using common sequences and reconstruction techniques. This hampers the evaluation of dynamics of rapidly moving samples. In this abstract, initial results of rapidly moving samples in form of SPION boluses visualized within an MPI scanner are shown.
https://doi.org/10.18416/IJMPI.2023.2303044
MHD flow of submerged jets behind the inlet disturbance. - In: Proceedings in applied mathematics and mechanics, ISSN 1617-7061, Bd. 22 (2023), 1, e202200200, S. 1-6
In a broad variety of configurations in technology and industrial applications, the properties of liquid metal flows subjected to strong magnetic fields, are largely governed by the dynamics of coherent structures, known to settle several basic types, such as thin shear layers, forming near the walls or within the fluid domain, vortices extended along the field, or planar and round jets. In some cases, these structures are created by the design, like a submerged jet formed by a sudden expansion from the nozzle into a blanket channel, or jets formed behind some flow obstruction. In the other cases this may be due to instability and evolution of secondary structures, for example, descending and ascending jets appearing as a result of convective instability in blanket channels. In this study, we undertake an attempt to affect liquid metal flow via inlet disturbance formed by a simple rod placed along the magnetic induction lines. The disturbance can generate flat jets behind the rod and, furthermore, a sustainable flow of anisotropic vortical perturbations further downstream the flow. We seek to analyze the most important mechanisms of the flow dynamics and effects of magnetic field on the integral system properties of enhancing mixing, mass and heat transport for such flow. The most optimal regimes of vortex generation are found to be governed by the magnetic interaction parameter (Stuart number). The exact ratio of the optimal Stuart number is found to be in a range between 20 and 40, based on the channel double width as a characteristic size. The observed vortices attain quasi-2D shape and exist at a length of dozens of duct calibers, being the strongest at higher flow rates. The obtained flow regimes and their turbulent properties are also found to resemble significant similarity to the results on quasi-2D turbulence found in prior studies of channel and duct flows under spanwise magnetic field.
https://doi.org/10.1002/pamm.202200200
Analytical description of transversally symmetrical hinges :
Analytische Beschreibung transversalsymmetrischer Gelenke. - In: Neunte IFToMM D-A-CH Konferenz 2023, (2023), insges. 2 S.
https://doi.org/10.17185/duepublico/77402
Determination and characterization of the influences of the bike frame on eBike drive units as the basis for their design and optimization. - In: Neunte IFToMM D-A-CH Konferenz 2023, (2023), S. 1-7
In this paper, the influence of the bike frame on the loading of the eBike drive unit is determined. For this purpose, relevant load cases and boundary conditions are derived based on the existing norms for the individual consideration of the frame and the drive. In this context, external loads on the frame and the forces acting on the engine must be taken into account. The following simulative study shows that the bike frame has an enormous and load-dependent influence on the load situation of the frame interface and the stresses within the housing of the drive unit. In general, this influence can be explained by the stiffness of the frame construction. Altogether, these results show that the design of the eBike drive unit according to its current standard requirements is not sufficient to cover these enormous influences of the bike frame.
https://doi.org/10.17185/duepublico/77395
Characterization and alignment of the flexure mechanism for the new Kibble balance at NIST. - In: ASPE Annual Meeting 2022, (2023), S. 80-84
TMS and fMRI-based localization of the attention network. - In: Brain stimulation, ISSN 1876-4754, Bd. 16 (2023), 1, S. 291-292
Richtiger Name des 4. Verfassers: Jens Haueisen
https://doi.org/10.1016/j.brs.2023.01.517
Closed-loop robotic TMS motor mapping using an online-optimized sampling scheme. - In: Brain stimulation, ISSN 1876-4754, Bd. 16 (2023), 1, S. 320
https://doi.org/10.1016/j.brs.2023.01.593
Fill level measurements using an M-sequence UWB radar. - In: International journal of microwave and wireless technologies, ISSN 1759-0795, Bd. 15 (2023), 1, S. 74-81
Due to increasingly complex and automated manufacturing processes, the demands on the control parameters of these processes are also increasing. In many applications, such a parameter is the fill quantity, whose precise determination is of ever growing importance. This paper shows with which accuracy and precision an M-sequence ultra-wideband radar can determine levels in small metallic and non-metallic containers with contact-based and contactless measurements. First, the principle of level measurement using guided wave radar is explained and the measurement setup is described. Afterward, the measurement results are shown and discussed. The measurements show that the level can be measured with an accuracy of better than 0.5 mm. In addition, level fluctuations can be detected with a precision of 3 μm. Based on the results of the guided wave radar, the possibilities of volumetric contactless measurement using an electrically small patch antenna are discussed. A particular challenge in contactless level measurement is the high number of multipath components, which strongly influence the accuracy. In addition, there are near-field effects when measuring close to the antenna. Exploiting these near-field effects, an additional method to accurately determine the full state of the container is investigated.
https://doi.org/10.1017/S1759078722000502
Model signatures for design and usage of simulation-capable model networks in MBSE. - In: Product lifecycle management, (2023), S. 155-164
Product development is characterised by numerous synthesis and analysis loops. Analysis provides information on the fulfillment of the required properties of the system under development. Analysis results therefore are an important basis for further synthesis steps. In the context of Model-Based Systems Engineering (MBSE), different types of simulation models play an important role. The overall system (product) can be broken down to system elements. For each system element a set of models has to be established, that provides the required degrees of fidelity, representations of system properties, flows, etc. reflecting the variety of modelling purposes. These models have to be integrated horizontally (same system level along the relevant flows of material, energy, and information) and vertically (aggregation from subsystem level to the overall system level, refinement in the opposite direction) to create a holistic model-based system representation. An important and challenging task is to identify and shape relevant subsystem models. In order to define an appropriate structure of these models, model developers may utilize criteria like selected properties of system elements and interrelations, their degree of detail or modelling assumptions. The relevant criteria have to be made transparent. For this purpose, the paper discusses the concept of model signatures that contain relevant meta information about each single model of all system elements, subsystems up to models of the overall system. This standardized meta information enables an identification and selection of those models and the decision on the necessary model integration. The concept is discussed on the basis of a roller bearing as an example out of an electro-mechanical drivetrain. A potential analysis provides information about the possible usage of the model signatures concept.
https://doi.org/10.1007/978-3-031-25182-5_16