21 research outputs found

    A flow-induced structure-based kinetic energy harvester

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    In this paper, a strategy utilizing a pair of cylinders which are put on the both sides of the cantilever beam and perpendicular to the water flow direction to harvest the energy is demonstrated. The novel flow induced structure based energy harvester consists of a pair inducing objects (cylinders) and one L-type cantilever beam. Macro fiber composite (MFC) is attached at the fixed end of the cantilever beam to convert the kinetic energy into electric power. The structure could induce the vortex shedding from the upstream flow and harvest the energy from it. Compared with the former studies with one or series layout inducing objects, the proposed structure could both improve the power output of flow induced energy harvester and avoid the damage happening in complex working conditions. Analytical modelling and experiment methods are both utilized in the research to cross verify the results. The characteristics related with water flow speed and center distance variations between inducing objects are discussed in the paper as well. It is found that when the water flow speed is 0.2m/s and the center distance is 30mm, the output power is optimal of 0.16μW and the power density is 0.4mW/m2

    Energy harvesting utilizing reciprocating flow-induced torsional vibration on a T-shaped cantilever beam

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    This paper proposes a T-shaped cantilever energy harvester powered by flow-induced torsional vibration. To collect and convert the mechanical (kinetic) energy into electric power, a pair of symmetrical acrylic cylindrical bluff bodies were installed onto the bottom surface of the T-shaped cantilever beam, one at each end; There is also one patch of Macro Fiber Composite (MFC) used as an energy collector and converter which was attached to the fixed end of the cantilever beam. This proposed setup of the energy harvester is able to generate sustainable electric power by harvesting natural mechanical power resulted from the torsional vibration of the beam due to fluid's vortex shedding effects. The proposed energy harvester has the novelty in that our approach harvests fluid flow's energy in a reciprocal fashion making full use of renewable energy incurred in areas surrounding the two bluff bodies. Both the theoretical and experimental analyses on the proposed energy harvesting structure were performed and demonstrated in this paper. The case in the test rig we studied on the proposed energy harvester was able to generate sustainable electric power of approximately 1.0 µW when flow speed was measured to be 0.33 m/s flowing through two bluff bodies each of 29.5 mm diameter. This work also looks into and discusses pros and cons of various scenarios in terms of structural geometric variations for system optimization of the proposed energy harvester

    Intelligent control of a multi-degree-of freedom reaction compensating platform system using fuzzy logic

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    This paper presents the development of a general-purpose fuzzy logic (FL) control methodology for isolating the external vibratory disturbances of space-based devices. According to the desired performance specifications, a full investigation regarding the development of an FL controller was done using different scenarios, such as variances of passive reaction-compensating components and external disturbance load. It was shown that the proposed FL controller is robust in that the FL-controlled system closely follows the prespecified ideal reference model. The comparative study also reveals that the FL-controlled system achieves significant improvement in reducing vibrations over passive systems

    3D simulation and parametric analysis of polymer melt flowing through spiral mandrel die for pipe extrusion

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    With the increasing demands for large scale and high productivity, polymer pipes are recently produced using the advanced spiral mandrel dies. However, the fundamental research related to polymer melt flow mechanism in the spiral mandrel die for pipe extrusion is lagging behind. In the present study, the mathematical model for such a complex three-dimensional non-isothermal viscous flow of polymer melts obeying power law model was developed based on computational fluid dynamics (CFD) theory. Finite volume element method was applied to predict the rheological behaviours of polymer melt flowing through the complex flow channel. The essential flow characteristics including velocity, pressure drop, wall shear stress and temperature were investigated. The effects of both mandrel structure parameters and mass flow rate upon the flow patterns were further discussed. Some recommendations on spiral mandrel die design for pipe production were put forward

    Combined Phytochemistry and Chemotaxis Assays for Identification and Mechanistic Analysis of Anti-Inflammatory Phytochemicals in Fallopia japonica

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    Plants provide a rich source of lead compounds for a variety of diseases. A novel approach combining phytochemistry and chemotaxis assays was developed and used to identify and study the mechanisms of action of the active compounds in F. japonica, a medicinal herb traditionally used to treat inflammation. Based on a bioactivity-guided purification strategy, two anthranoids, emodin and physcion, were identified from F. japonica. Spectroscopic techniques were used to characterize its crude extract, fractions and phytochemicals. The crude extract, chloroform fraction, and anthranoids of F. japonica significantly inhibited CXCR4-mediated chemotaxis. Mechanistic studies showed that emodin and physcion inhibited chemotaxis via inactivating the MEK/ERK pathway. Moreover, the crude extract and emodin could prevent or treat type 1 diabetes in non-obese diabetic (NOD) mice. This study illustrates the applicability of a combinational approach for the study of anti-inflammatory medicine and shows the potential of F. japonica and its anthranoids for anti-inflammatory therapy

    Comprehensive mPoint: A Method for 3D Point Cloud Generation of Human Bodies Utilizing FMCW MIMO mm-Wave Radar

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    In this paper, comprehensive mPoint, a method for generating 3D (range, azimuth, and elevation) point cloud of human targets using a Frequency-Modulated Continuous Wave (FMCW) signal and Multi-Input Multi-Output (MIMO) millimeter wave radar is proposed. Distinct from the TI-mPoint method proposed by TI technology, a comprehensive mPoint method considering both the static and dynamic characteristics of radar reflected signals is utilized to generate a high precision point cloud, resulting in more comprehensive information of the target being detected. The radar possessing 60–64 GHz FMCW signal with two sets of different dimensional antennas is utilized in order to experimentally verify the results of the methodology. By using the proposed process, the point cloud data of human targets can be obtained based on six different postures of the underlying human body. The human posture cube and point cloud accuracy rates are defined in the paper in order to quantitively and qualitatively evaluate the quality of the generated point cloud. Benefitting from the proposed comprehensive mPoint, evidence shows that the point number and the accuracy rate of the generated point cloud compared with those from the popular TI-mPoint can be largely increased by 86% and 42%, respectively. In addition, the noise level of multipath reflection can be effectively reduced. Moreover, the length of the algorithm running time is only 1.6% longer than that of the previous method as a slight tradeoff
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