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    Gelatin/Na2Ti3O7 Nanocomposite Scaffolds: Mechanical Properties and Characterization for Tissue Engineering Applications
    (2023-05-01)
    Sangkatip, Rittichai
    ;
    Jongwuttanaruk, Kaona
    ;
    Sriseubsai, Wipoo
    Materials and manufacturing technologies are necessary for tissue engineering and developing temporary artificial extracellular matrices. In this study, scaffolds were fabricated from freshly synthesized titanate (Na<inf>2</inf>Ti<inf>3</inf>O<inf>7</inf>) and its precursor titanium dioxide and their properties were investigated. The scaffolds with improved properties were then mixed with gelatin to form a scaffold material using the freeze-drying technique. To determine the optimal composition for the compression test of the nanocomposite scaffold, a mixture design with three factors of gelatin, titanate, and deionized water was used. Then, the scaffold microstructures were examined by scanning electron microscopy (SEM) to determine the porosity of the nanocomposite scaffolds. The scaffolds were fabricated as a nanocomposite and determined their compressive modulus values. The results showed that the porosity of the gelatin/Na<inf>2</inf>Ti<inf>3</inf>O<inf>7</inf> nanocomposite scaffolds ranged from 67% to 85%. When the mixing ratio was 100:0, the degree of swelling was 22.98%. The highest swelling ratio of 85.43% was obtained when the freeze-drying technique was applied to the mixture of gelatin and Na<inf>2</inf>Ti<inf>3</inf>O<inf>7</inf> with a mixing ratio of 80:20. The specimens formed (gelatin:titanate = 80:20) exhibited a compressive modulus of 30.57 kPa. The sample with a composition of 15.10% gelatin, 2% Na<inf>2</inf>Ti<inf>3</inf>O<inf>7</inf>, and 82.9% DI water, processed by the mixture design technique, showed the highest yield of 30.57 kPa in the compression test.
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    Agricultural Mobile Robot Body Vibration Characterization Using Integral Based Methodology
    (2019-04-01)
    Boksuwan, Sungwan
    ;
    Chesof, Abdulhafiz
    ;
    Wongvanich, Napasool
    ;
    Panaudomsap, Sumit
    This paper presents the application of integral based method for characterization of the vibration in the four-wheel agricultural mobile robot, which is designed for use in applications such trimming, spraying and harvesting. Vibration occurs when one of the wheels does not touch the ground which reduces an effective of end effector. In order to design an effective controller, an accurate mathematical model is needed. Results show that the proposed method can simplify the system identification procedure, while yielding excellent match in comparison to the standard black box method. The proposed algorithm gave an NRMSE match of 96.8%, while the standard method yielded a 76.1% match. This match is also found to be lower when the validation data was from other experiments.
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    Physical, electrical and optical properties of F/Sb Codoped SnO2 synthesized via sonochemical process
    (2016-01-02)
    Noonuruk, R.
    ;
    Mekprasart, W.
    ;
    Vittayakorn, N.
    ;
    Sritharathikhun, J.
    ;
    Pecharapa, W.
    F/Sb-codoped SnO<inf>2</inf> nanoparticles were synthesized via sonochemical process using stannic chloride pentahydrate (SnCl<inf>4</inf>·5H<inf>2</inf>O) as host precursor while antimony(III) chloride (SbCl<inf>3</inf>) and ammonium fluoride (NH<inf>4</inf>F) were chosen as Sb and F dopant precursors, respectively. Their physical properties and morphologies were investigated using X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy and transmission electron microscope while their electrical and optical properties were investigated by Hall measurement and diffuse reflectance spectroscopy. As-synthesized powder of polycrystalline phase SnO<inf>2</inf> nanoparticles can be obtained by one-step sonochemical process and its crystallinity can be improved by calcination process. The formation of crystalline phase of SnO<inf>2</inf> is assisted by cavitation effect provided by intense ultrasonic radiation via rapid collision. The characterization results disclose that Sb dopant has strong influence on both physical and electrical properties while F dopant provide considerable effect on electrical property of the samples. It is noticed that the codoping of both elements with certain contents can significantly heighten its electrical conductivity.
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    Comprehensive characterization of a novel UWB elliptical planar monopole antenna
    (2012-12-01)
    Marindra, Adi Mahmud Jaya
    ;
    Promwong, Sathaporn
    ;
    Takada, Jun Ichi
    The rise of research in ultra wideband (UWB) antenna design must be followed by a proper method of antenna characterization. The emerging concept of UWB impulse radio (UWB-IR) compels the performance evaluation of UWB antenna should be assessed in different ways from narrowband antennas. In this paper, a comprehensive characterization of UWB antenna will be discussed. Based on the theory of antenna transfer function in frequency domain, some UWB transmission parameters in time domain are derived, i.e. waveform correlation, waveform width stretch ratio, and waveform relative gain. For practical testing, we propose a novel UWB elliptical planar monopole antenna as the characterized antenna. The results show that the overall performance and characteristic of the proposed antenna is very good, especially at the antenna boresight. The derived parameters can quantitatively characterize the UWB antenna for all the measured directions so that the detail of transmission performance of the UWB antenna could be known. Hopefully, the characterization scheme with the proposed antenna presented in this paper provide useful insight either for UWB antenna design or for evaluating UWB antenna performance. © 2012 IEEE.