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Hu, D. (author), Wang, Chieh (author), Li, Z. (author), Gupta, N. (author), Poelma, René H. (author), Shi, Ziliang (author), Fan, J. (author), Zhang, Kouchi (author)Driven by the increasing demand for high-power systems, ceramic substrates have received more attention for handling higher power density. Warpage in active metal brazed (AMB) ceramic substrate becomes a critical issue as it can deteriorate the reliability performance. This study comprises three phases, including investigation of the cause of...conference paper 2024
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Hu, X. (author), Huang, Jianlin (author), Poelma, René H. (author), van Driel, W.D. (author), Zhang, Kouchi (author)Low-temperature sintering technology of Ag nanoparticles is widely used in high-power electronic device packaging. Utilizing simulation methods to comprehend and control the microstructure and properties of Ag sintering materials has emerged as a prominent research area. This work uses the General Form PDE module in COMSOL to simplify the...conference paper 2024
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Du, L. (author), Deng, Shanliang (author), Cui, Z. (author), Poelma, René H. (author), Beelen-Hendrikx, Caroline (author), Zhang, Kouchi (author)In this study, we combined finite element method (FEM) based on Ansys and Noesis Optimus software to investigate the effect of bump structures and loading conditions on the electromigration properties of solder bumps in WLCSP. A numerical model considering current density, vacancy concentration, stress and temperature was utilized to calculate...conference paper 2024
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Martin, H.A. (author), Reintjes, Marcia (author), Reijs, Dave (author), Dorrestein, Sander (author), Kengen, Martien (author), Libon, Sebastien (author), Smits, Edsger (author), Tang, Xiao (author), Koelink, Marco (author), Poelma, René H. (author), van Driel, W.D. (author), Zhang, Kouchi (author)Integrated Circuits and Electronic Modules experience concentrated thermal hot spots, which require advanced thermal solutions for effective distribution and dissipation of heat. The superior thermal properties of diamonds are long known, and it is an ideal material for heat-spreading applications. However, growing diamond films to the...conference paper 2023
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Du, L. (author), Zhao, Xiujuan (author), Poelma, René H. (author), van Driel, W.D. (author), Zhang, Kouchi (author)SnBiAgCu solder alloy is an attractive soldering material for temperature-sensitive electronic devices due to its excellent creep properties. This study firstly reports the creep properties of SnBiAgCu solder alloy under different temperatures. Results show that the addition of Bi resulted in better creep resistance compared with that of...conference paper 2023
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Hu, X. (author), Martin, H.A. (author), Poelma, René H. (author), Huang, J.L. (author), Rijckevorsel, H. (author), Scholten, H. (author), Smits, E.C.P. (author), van Driel, W.D. (author), Zhang, Kouchi (author)Resin-reinforced silver (Ag) sintering material is an effective and highly reliable solution for power electronics packaging. The hybrid material’s process parameters strongly influence its microstructure and pose a significant challenge in estimating its effective properties as a thin interconnect layer. This research demonstrates a novel 3D...conference paper 2023
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Hogendoorn, W.J. (author), Frank, David (author), Bruschewski, Martin (author), Poelma, C. (author)Using magnetic resonance imaging we are able to obtain average velocity and volume fraction profiles in a pipe flow with a neutrally buoyant suspension. In this experimental work, the effect of increasing Reynolds number and particle volume fraction on shear-induced migration is studied. For increasing bulk volume fraction, the initially...conference paper 2022
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Muller, K. (author), Greidanus, A.J. (author), Dash, A. (author), Poelma, C. (author)The circular Taylor-Couette flow is one of the archetypical model systems for the study of flow transitions and dynamic pattern formation in experimental fluid dynamics. The emergence of the internal vortical flow structures are commonly visualized through a rheoscopic flow visualization, while their spatio-temporal dynamics can be extracted by...conference paper 2022
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Nikolaidou, Lina (author), Laskari, A. (author), Poelma, C. (author), van Terwisga, T.J.C. (author)An air layer within a liquid turbulent boundary layer (TBL) is formed by controlled air injection underneath a flat plate. The incoming boundary layer as well as the flow around the air layer were measured with planar particle image velocimetry (PIV). The effect of different incoming liquid flow characteristics on the air layer geometry is...conference paper 2022
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Du, L. (author), Zhao, Xiujuan (author), Watte, Piet (author), Poelma, René H. (author), van Driel, W.D. (author), Zhang, Kouchi (author)The objective of this article is to investigate the thermal-fatigue properties of a commercially available lead-free solder alloy (SnBiAgCu) under the use of different types of potting compounds. Solder alloys with lower silver content are expected to substitute the conventional solder alloys SAC305 (Sn-3.0Ag-0.5Cu). First, the tensile...conference paper 2022
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Jahangir, S. (author), Ghahramani, Ebrahim (author), Neuhauser, Magdalena (author), Bourgeois, Sébastien (author), Bensow, Rickard E. (author), Poelma, C. (author)The objective of this study is to investigate the collapsing behavior of cavitation, which leads to erosion. For this purpose, an experimental investigation was performed in a channel with a semi-circular cylinder obstacle at the Hydraulic Laboratory of ANDRITZ HYDRO in Vevey. Cavitation was achieved by employing a range of pressure differences...conference paper 2019
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Hogendoorn, W.J. (author), Poelma, C. (author)Using ultrasound in plane wave imaging mode, in combination with a proper processing strategy and the covariance function approach, we can not only better estimate the actual turbulence statistics, but we are also able to measure turbulent flows with much higher Reynolds numbers. Optimising the processing strategy by using a sliding correlation...conference paper 2019
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Dash, A. (author), Anantharaman, Arjun (author), Greidanus, A.J. (author), Poelma, C. (author)Ultrasound Imaging Velocimetry (UIV) is applied to a Taylor-Couette flow, for the case of pure inner cylinder rotation. By imaging a radial-azimuthal plane, two velocity components are obtained simultaneously in a two-dimensional plane. For the single-phase flow studies, Iriodin flakes (commonly used for visualizing flow structures) are used as ...conference paper 2019
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Schreier, S. (author), Cornel, W.A. (author), Poelma, C. (author)The dynamic response of pressure sensors for model tests of sloshing impacts is paramount to recording these highly dynamic events. In this study, we investigated the dynamic behavior of the new pressure sensors presented at ISOPE 2018 (Schreier and Poelma, 2018), which increased the spatial resolution of sloshing pressure measurements by a...conference paper 2019
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Jahangir, S. (author), Wagner, E.C. (author), Mudde, R.F. (author), Poelma, C. (author)Cavitation is a complex multiphase phenomenon, where the production of vapor bubbles leads to opaqueness of the flow. While it is nearly impossible to visualize the interior of the cavitation region with visible light, we show that with X-ray computed tomography it is possible to obtain the time-averaged void fraction distribution in an...conference paper 2018
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Cornel, W.A. (author), Westerweel, J. (author), Poelma, C. (author)The challenge presented in this research is to determine the local volumetric bubble concentration (or void fraction) in the center of a microbubble cloud with limited optical access and without disturbing the flow. By applying defocused volumetric shadowgraphy to an aerated water column we were able to measure the characteristics of single...conference paper 2018
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van Meerkerk, M. (author), Poelma, C. (author), Westerweel, J. (author)A quasi three-dimensional stereo-camera measurement technique has been devised that is able to measure liquid free surface profiles, by scanning a light sheet. The technique will be applied to study the variability of impact pressure observed during wave impact in a newly developed experimental set-up. The set-up imposes severe optical (single...conference paper 2018
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Gotfredsen, Erik (author), Kunoy, Jens D. (author), Mayer, Stefan (author), Poelma, C. (author), Westerweel, J. (author), Meyer, Knud Erik (author)The effect of pulsations in a catalyst converter is investigated with the aim of determining if a steady flow captures the same physical phenomena as the pulsating flow. For this specific case, guide vanes are mounted in the sudden expansion to obtain a uniform inlet flow to the catalytic layers. The test rig is successfully validated against...conference paper 2018
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Schreier, S. (author), Poelma, C. (author)Sloshing impacts are highly dynamic and localized events. One problem in the measurement of sloshing impact pressures is the limited spatial resolution that can be achieved with current sensors. To overcome this hurdle a project was started to develop new sensors that allow to increase the spatial resolution of pressure measurements by a factor...conference paper 2018
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Middelburg, L.M. (author), el Mansouri, B. (author), Poelma, René H. (author), van Zeijl, H.W. (author), Wei, J. (author), Zhang, Kouchi (author), van Driel, W.D. (author)The mechanical part of inertial sensors can be designed to have a large mechanical sensitivity, but also requires the transduction mechanism which translates this displacement. The overall system resolution in mechanical inertial sensors is dictated by the noise contribution of each stage and the magnitude of each sensitivity, see also Figure...conference paper 2018
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