Mock circulatory systems (MCS) are often used for the development of cardiovascular devices and for the study of the dynamics of blood flow through the cardiovascular system. However, conventional MCS suffer from the repeatability, flexibility, and precision problems because they are typically built up with passive and linear fluidic elements such as compliance chamber, manual valve, and tube. To solve these limitations, we have developed an impedance simulator, comprised of a feedback-controlled positive displacement pump that is capable of generating analogous dynamic characteristics as the conventional fluidic elements would generate, thereby replacing the conventional passive fluidic elements that often cause problems. The impedance simulator is experimentally proven to reproduce the impedance of the various discrete elements, such as resistance and compliance of the cardiovascular system model, as well as the combined impedances of them.
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http://dx.doi.org/10.1109/TBME.2009.2030498 | DOI Listing |
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December 2024
Shaanxi Key Laboratory of Macromolecular Science and Technology, School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi'an, 710072, P. R. China.
The demand for temperature-robust electromagnetic wave (EMW) absorption materials is escalating due to the varying operational temperatures of electronic devices, which can easily soar up to 100 °C, significantly affecting EMW interference management. Traditional absorbers face performance degradation across broad temperature ranges due to alterations in electronic mobility and material impedance. This study presented a novel approach by integrating semiconductor metal-organic frameworks (SC-MOFs) with paraffin wax (PW), leveraging the precise control of interlayer spacing in SC-MOFs for electron mobility regulation and the introduction of paraffin wax for temperature-inert electromagnetic properties.
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December 2024
School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, China.
A ridge-loaded staggered double-vane slow-wave structure is proposed for terahertz radiation sources employing a sheet electron beam. This slow-wave structure has the advantages of enhanced electric field and energy density distribution and improved interaction impedance in the beam-wave interaction region. High-frequency characteristics are investigated for the proposed slow wave structure and compared with those of the staggered double-vane slow wave structure.
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December 2024
Department of Theoretical Electrical Engineering and Diagnostics of Electrical Equipment, Institute of Electrodynamics, National Academy of Sciences of Ukraine, Beresteyskiy, 56, Kyiv-57, Kyiv, 03680, Ukraine.
In this paper, an improved voltage control strategy for microgrids (MG) is proposed, using an artificial neural network (ANN)-based adaptive proportional-integral (PI) controller combined with droop control and virtual impedance techniques (VIT). The control strategy is developed to improve voltage control, power sharing and total harmonic distortion (THD) reduction in the MG systems with renewable and distributed generation (DG) sources. The VIT is used to decouple active and reactive power, reduce negative power interactions between DG's and improve the robustness of the system under varying load and generation conditions.
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December 2024
Faculty of Mechanical Engineering, Department of Machining, Assembly and Engineering Metrology, VSB-Technical University of Ostrava, Ostrava-Poruba, 708 00, Czech Republic.
The aim of this work is to investigate the sound absorption properties of open-porous polyamide 12 (PA12) structures produced using Selective Laser Sintering (SLS) technology. The examined 3D-printed samples, fabricated with hexagonal prism lattice structures, featured varying thicknesses, cell sizes, and orientations. Additionally, some samples were produced with an outer shell to evaluate its impact on sound absorption.
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December 2024
The Naval Architecture and Ocean Engineering College, Dalian Maritime University, Dalian 116026, China.
The inherent passive impedance characteristics of soft robotic arms provide excellent environmental adaptability. When a soft robotic arm interacts with its surroundings, its passive impedance responds swiftly, preventing rigid collisions that could damage the arm and ensuring high safety. However, during the movement of the soft robotic arm, these passive impedance properties are uncontrollable, making it impossible to achieve precise impedance control in constrained environments by relying solely on passive mechanisms.
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