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Hung Tran Viet,Thanh Nguyen Chi,Thang Le Xuan,Nhung Nguyen Cam,Thuc Ngo Van,Hoa Tran 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.6
This paper proposes a novel approach for structural damage identification using the Salp Swarm Algorithm (SSA) combined with Orthogonal Diagonalization (OD). SSA is an optimization algorithm developed in recent years and has been considered for addressing complex and computationally expensive engineering problems. However, due to the utilization of only the leader salp to search for optimal solutions, there is an imbalance between the exploitation and exploration capabilities of the salp swarm. To address this issue, we suggest the use of OD to enhance the search capability of the leader salp. OD plays a crucial role in reducing the search space and selecting high-quality salp elements in subsequent iterations. From that idea, the algorithm is tested with 12 benchmark functions, and the results demonstrate superior convergence for all of these compared to the algorithm without OD. A comprehensive study with various damage scenarios is also conducted with the Cua Rao bridge. The outcomes indicate that the accuracy, with a deviation rate when using OD, is only 1.412%, whereas it is 2.224% for the SSA in the case of a single damage scenario. As the number of damaged elements increases, the error of SSA rises to 99.667% when identifying damaged elements, while errors using OD remain below 10%. Additionally, the computational speed is significantly enhanced by approximately 40% in both scenarios.
The Role of Zn Doping on the Catalytic Activity of the Nanoparticle Perovskite La0.7Sr0.3MnO3
Tran Thi Minh Nguyet,Nguyen Quang Huan,Tran Que Chi,Do The Chan,Nguyen Doan Thai,Nguyen Cong Trang,Luu Tien Hung,Le Van Tiep,Nguyen Van Qui 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.5
The nanometer complex oxide La0:7Sr0.3Mn0.6Zn0.₄O₃ was prepared by using a Sol-Gel method with citric acid as a ligand. The in uence of Zn doping of La0.7Sr0.₃MnO₃ on the structure, the morphology, the surface properties and on the catalytic activity of material was studied by using X-ray diraction (XRD), transmission electron microscopy (TEM), a high-resolution images and selected area electron diraction (SAED), physical adsorption and temperature programmed surface reaction (TPSR) methods. The results showed that perovskite La0:7Sr0:3Mn0:6. Zn0.₄O₃ could well catalyse propene oxidation in the temperature range 190 { 280 ℃, which was reduced to 100 { 120 ℃ for catalyst La1-χSrχMnO₃ The nanometer complex oxide La0:7Sr0.3Mn0.6Zn0.₄O₃ was prepared by using a Sol-Gel method with citric acid as a ligand. The in uence of Zn doping of La0.7Sr0.₃MnO₃ on the structure, the morphology, the surface properties and on the catalytic activity of material was studied by using X-ray diraction (XRD), transmission electron microscopy (TEM), a high-resolution images and selected area electron diraction (SAED), physical adsorption and temperature programmed surface reaction (TPSR) methods. The results showed that perovskite La0:7Sr0:3Mn0:6. Zn0.₄O₃ could well catalyse propene oxidation in the temperature range 190 { 280 ℃, which was reduced to 100 { 120 ℃ for catalyst La1-χSrχMnO₃
Experiment on Nearest Level Modulation algorithm for FPGA based Modular Multilevel Converters
Tran Hung Cuong,Pham Viet Phuong,Tran Van Phuong,Tran Trong Minh 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5
Modular Multilevel Converters (MMC) have many advantages in comparison with conventional multilevel converters in application to high voltage system. However, the control system of MMC requires a large amount of I/O signal ports which cannot be generated by a single digital signal processor (DSP) with maximum I/O port of 24. This paper fucuses on the experimental results of aMMC that uses a Field Programmable Gate Array (FPGA) in which embedge the Nearest Level Modulation (NLM) method and capacitor voltage balancing algorithm. The MMC consists of 12 Sub-Modules (SM) in each phase to generate a 13-level ac output voltage. Applying the NLM method and capacitor voltage balancing algorithm have significantly reduced the switching frequency and produced an ac output voltage with very low harmonic distortion. The experimental results have verified by a laboratory-scale prototype and compared with the simulation results.
Hoang, Van Thanh,Luu, Duc Binh,Toan Do, Le Hung,Tran, Ngoc Hai,Nguyen, Pham The Nhan,Tran, Minh Sang,Tran, Minh Thong Materials Research Society of Korea 2020 한국재료학회지 Vol.30 No.12
A combination of Polycarbonate (PC) material and Polymethylmethacrylate (PMMA), fabricated using an injection molding machine, has been investigated to determine its advantages, as studied in Ref. 1). This paper aims to investigate the optimization of PMMA/PC blend for both tensile yield strength and impact strength. Furthermore, interaction effects of process conditions on mechanical properties including tensile yield strength and impact strength of PMMA/PC blend by injection molding process are interpreted in this study. Tensile and impact specimens are designed following ASTM, type V, and are fabricated by injection molding process. The processing conditions such as melt temperature, mold temperature, packing pressure, and cooling time are applied; each factor has three levels. As a result, in comparison with optimization of separated responses, mechanical properties of PMMA/PC are found to decrease when optimizing both tensile and impact strengths simultaneously. The melt temperature is found to be the most significant interaction parameter with the mold temperature and packing pressure. In addition, there is more interaction between the mold temperature and cooling time. This investigation provides a useful understanding of the control of injection molding processing of polymer blends in optical application.
Effect of boattail angle on near-wake flow and drag of axisymmetric models: a numerical approach
The Hung Tran,Hoang Quan Dinh,Hoang Quan Chu,Van Quang Duong,Chung Pham,Van Minh Do 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.2
Flow behavior around axisymmetric boattail surface was studied by numerical methods. A wide range of boattail angles from 0° to 24° was investigated to find the drag trend of the model. Numerical simulation was validated by experimental results with the same flow conditions. Results showed that the use of boattail model always has a positive effect on drag reduction. Total drag showed minimum value at boattail model of around 14°. Length of the recirculation after body decreases with increasing boattail angle up to 14° and then becomes constant at higher angle. The trend of boattail pressure drag showed similar to previous studies for high-speed flow. However, base drag showed different trend to previous observation. The base drag showed to be the most important parameter to determine drag trend of the model. The effect of flow fields around boattail on pressure distribution and drag is discussed in detail.
The Hung Tran,Cong Truong Dao,Dinh Anh Le,Van Khiem Pham,Van Minh Do,Trang Minh Nguyen 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.12
This study examines the drag trend and flow behavior of axisymmetric models with conical boattails under subsonic and supersonic conditions by using a numerical approach. Mach numbers ranging from 0.1 to 3.0 and boattail angles varying from 0° to 24° are investigated. The numerical results are validated by experimental data under identical flow conditions. The flow behavior around the boattail body, the total drag, and the pressure distribution are analyzed in detail. The drag components acting on the boattail surface are examined to determine the reason for the change in drag due to different boattail angles and Mach number conditions. Results show that the minimum drag is around 14° for subsonic flow, but this value suddenly decreases to around 7° for supersonic flow. Formalization of the expansion and oblique shocks on the boattail is the main cause of changes in the pressure distribution on the surfaces, which in turn affect the drag trend. Moreover, the relationships among boattail angle, flow conditions, and four flow types on the boattail surface are presented in detail.
Van Noi Nguyen,Thi Dieu Cam Nguyen,Thanh Phuong Dao,Hung Thuan Tran,Dinh Bang Nguyen,안대희 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.2
Organoclays were synthesized by exchanging inorganic cations between layers in Thanh Hoa bentonite using organic cations including benzylhexadecyldimethylammonium (BHDDM+), dimethyldioctadecylammonium (DMDOD+) and benzylstearyldimethylammonium (BSDM+). Inserting organic cations increases material interlayer distance significantly (from 15 A˚ to 40 A˚ ) and simultaneously enhances affinity of materials toward organic pollutants. The results show that adsorption capacity of organics on organoclays strongly depends on affinity between organic substances and ammonium cations rather than on interlayer distance of organoclays. This means that the sorption of organoclays for organic contaminants was significantly influenced by the nature of the surfactants added to the clay.
Anti-inflammatory compounds from Ampelopsis cantoniensis.
Van Thu, Nguyen,Cuong, To Dao,Hung, Tran Manh,Van Luong, Hoang,Woo, Mi Hee,Choi, Jae Su,Lee, Jeong-Hyung,Kim, Jeong Ah,Min, Byung Sun Natural Product Communications 2015 Natural product communications Vol.10 No.3
<P>Many natural products have been shown to have an inhibitory effect on nitric oxide (NO), and are used as chemotherapy agents for inflammation disease. The current study was designed to evaluate the anti-inflammatory activity of chemical components from the leaves of Ampelopsis cantoniensis. Sixteen compounds (1-16) were isolated and identified. Phloretin (5) and 5,7,3',5'-tetrahydroxyflavanone (16) inhibited nitric oxide (NO) production with IC50 values of 5.2, and 18.5 μM, respectively. The inhibitory effect of compounds 5 and 16 were accompanied by dose-dependent decreases in LPS-induced nitric oxide synthase (iNOS) in RAW 264.7 cells, respectively. This study investigated the significant anti-inflammatory properties of isolated compounds from the leaves of A. cantoniensis for the first time. The findings demonstrate that A. cantoniensis could be used beneficially in the treatment of inflammation disease.</P>