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Results 321-330 of 698 (Search time: 0.004 seconds).
    • Enhanced anti-corrosion and microwave absorption performance with carbonyl iron modified by organic fluorinated chemicals
    Authors: Xianyu, Jianga; Weihong, Wana; Bo, Wang;  Advisor: -;  Co-Author: - (2021)

    Magnetic absorbing materials suffer from corrosion and aging in harsh environments such as ocean and acid, which limits their practical applications. Therefore, it is important to design a material with excellent corrosion resistance and microwave absorption properties. Herein, perfluorooctyltriethoxysilane (PFOTES) modified carbonyl iron (CI) with tunable PFOTES content was prepared by the sol–gel method. The presence of PFOTES layer improved the corrosion resistance and microwave absorption of CI. The good hydrophobicity of PFOTES layer with the static contact angle of 129.73° hindered the contact of corrosive medium with CI core. The corrosion current of CI@PFOTES composite decreased significantly, and the corrosion rate was reduced by three orders of magnitude. The surface coati...
    • Enhanced anti-corrosion and microwave absorption performance with carbonyl iron modified by organic fluorinated chemicals
    Authors: Xianyu, Jianga; Weihong, Wana; Bo, Wang;  Advisor: -;  Co-Author: - (2022)

    Magnetic absorbing materials suffer from corrosion and aging in harsh environments such as ocean and acid, which limits their practical applications. Therefore, it is important to design a material with excellent corrosion resistance and microwave absorption properties. Herein, perfluorooctyltriethoxysilane (PFOTES) modified carbonyl iron (CI) with tunable PFOTES content was prepared by the sol–gel method. The presence of PFOTES layer improved the corrosion resistance and microwave absorption of CI. The good hydrophobicity of PFOTES layer with the static contact angle of 129.73° hindered the contact of corrosive medium with CI core. The corrosion current of CI@PFOTES composite decreased significantly, and the corrosion rate was reduced by three orders of magnitude. The surface coati...
    • Access Management in Joint Sensing and Communication Systems: Efficiency Versus Fairness
    Authors: Trung Thanh, Nguyen; Khaled, Elbassioni; Nguyen, Cong Luong;  Advisor: -;  Co-Author: - (2022)

    In this paper, we consider a distributed joint sensing and communication (DJSC) system in which each radar sensor as a JSC node is equipped with a sensing function and a communication function. Deploying multiple JSC nodes may require a large amount of bandwidth. Therefore, we investigate the bandwidth allocation problem for the DJSC system. In particular, we aim to optimize the bandwidth allocation to the sensing function and the communication function of the JSC nodes. To improve the allocation efficiency while benefiting the spatial diversity advantage of the DJSC systems, the objective is to maximize the sum of sensing performances, i.e., estimation rates, communication performances, i.e., communication data rates, and fairness of all the users. The optimization problem is non-c...
    • To pay or not to pay that is the question - for air pollution mitigation in a world’s dynamic city: An experiment in Hanoi, Vietnam
    Authors: Quy Van, Khuc; Duy, Nong; Tri Phu, Vu;  Advisor: -;  Co-Author: - (2022)

    This paper aims to investigate the air pollution issues in Hanoi – one of the most air polluted cities in the world in recent years – on residents’ and foreign visitors’ perceptions and how their trust in the local government to establish a joint funding mechanism to mitigate air pollution in Hanoi. Such information is fundamental in order to establish an effective and efficient program to improve air quality not only in Hanoi, but also in many cities around the world. We employ a random stratified approach coupled with the contingent valuation survey and an interval regression model over a sample of 475 residents and 75 foreigners.
    • “A novel system for non-destructive evaluation of surface stress in pipelines using rotational continuous magnetic Barkhausen noise”, Measurement 136 (2019) 761-774.
    Authors: Tu Le Manh;  Advisor: -;  Co-Author: O. Labra; P.Martinez-Ortiz; J.M. Hallen; J.A.Perez-Benitez (2019)

    In the present work a new system for nondestructive evaluation of applied stress on the pipeline steels surface is proposed. This system is based on applying a magnetic field on the pipe surface, whose direction changes due to rotatory permanent magnets. The variation of magnetic field direction produces the Barkhausen signal, which is measured by a pick-up coil. The angular dependence of the magnetic Barkhausen noise signal energy is influenced by the pipe surface curvature due to the changing headprobe liftoff. Also, the said angular dependence changes with the applied tensile stress due to the magneto-elastic effect. The result of Barkhausen noise measurements in the pipeline surface submitted to applied tensile stress reveals that, since the effect of curvature on the angular de...