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Trong-Ha Nguyen,Ngoc-Long Tran,Duy-Duan Nguyen 한국강구조학회 2022 International Journal of Steel Structures Vol.22 No.1
The steel oval hollow section (OHS) provides an aesthetic architecture and a greater local buckling strength. However, the existing design codes do not specify the eff ective width in calculating the load-bearing capacity of OHS members. This study aims to predict the axial compression capacity (ACC) of cold-formed steel OHS columns using artifi cial neural network (ANN) and adaptive neural fuzzy inference system (ANFIS) models. A total of 128 data sets collected from the literature were utilized to develop the ANN and ANFIS models. The performance of the two machine learning models was compared with three existing design codes. The results demonstrated that the developed ANN and ANFIS models predicted the ACC of steel OHS columns more accurately compared to the existing formulas. Specifi cally, the ANN model revealed a superior performance with the highest coeffi cient of determination and the smallest root means square errors. Moreover, the formulas based on ANN and ANFIS models, which accommodates all input parameters, were proposed to predict the ACC of coldformed steel OHS columns. The thickness of the cross-section was the most infl uential parameter on the ACC of the OHS column. By contrast, the column length negatively aff ected the ACC value of the steel column. Finally, a graphical user interface tool was developed to readily calculate the ACC of the steel OHS columns.
Trong-Ha Nguyen,Ngoc-Long Tran,Duy-Duan Nguyen 한국강구조학회 2021 International Journal of Steel Structures Vol.21 No.4
The web tapered I-section steel (WTIS) columns have been widely used in civil and industrial steel structures. However, the existing theoretical and empirical equations demonstrate a signifi cant discrepancy in estimating the critical axial load of the WTIS columns. This study aims to develop eff ective artifi cial neural networks (ANNs) for predicting the critical buckling load of the WTIS columns. A database of 269 fi nite element models of WTIS columns was generated, after verifying with experimental results, to develop the ANN model. The results of the proposed ANN model were also compared with those of existing formulas, highlighting that the ANN model in this study predicts the critical buckling load of the WTIS columns more accurately than the existing formulas. Moreover, the infl uences of input parameters on the critical buckling load of the WTIS columns were thoroughly investigated. An ANN-based formula, which considers input variables, was thereafter proposed to estimate the critical buckling load of the WTIS columns. Additionally, a graphical user interface tool has been developed for simplifying the design practice of the WTIS columns.
Trong-Ha Nguyen,Van-Tien Phan,Duy-Duan Nguyen 한국강구조학회 2023 International Journal of Steel Structures Vol.23 No.6
This study develops an artificial neural network (ANN) to estimate the critical buckling load (CBL) of corroded web-tapered steel I-section (WTSI) columns in pre-engineered steel buildings. A total of 387 datasets are employed to develop the ANN model. The datasets are generated from the proposed analytical model and Newton–Raphson method. The input parameters of the developed ANN model contain the cross-sectional dimensions of the steel column (i.e., the top and bottom flange width, top and bottom flange thickness, maximum section height, minimum section height, and web thickness), elastic modulus of material, and the column height. Meanwhile, the CBL is the output parameter of the ANN model. A predictive process for the CBL of the corroded WTSI columns has been proposed based on the ANN model and previous corrosion model. Results reveal that the ANN model showed an excellent performance in predicting the CBL of the corroded steel columns. The R2 values of the training, testing, and validation data are 0.99975, 0.99916, and 0.99951, respectively. The root-mean-squared errors of the training, testing, and validation data are 96.705 (kN), 103.402 (kN), and 103.200 (kN), respectively. Additionally, the a20-index is very close to 1.0. Moreover, a graphical user interface tool is constructed to facilitate the CBL calculation of the corroded WTSI columns.
Van-Truc Nguyen,Thanh-Binh Nguyen,Thi-Dieu-Hien Vo,Nguyen Duy Dat,Thi-Kim Quyen Vo,Xuan Cuong Nguyen,Viet-Cuong Dinh,Thi-Ngoc-Chau Le,Thi-Giang-Huong Duong,Manh-Ha Bui,Xuan-Thanh Bui 대한환경공학회 2023 Environmental Engineering Research Vol.29 No.3
This study explores the adsorption of doxycycline (DOX) from aqueous solutions onto biochar derived from banana peel, which was prepared using a potassium hydroxide activation method (KOH-BPB). The biochar properties were characterized based on morphology, surface area (SBET of 710.241 ㎡ g<SUP>−1</SUP>), functional groups, and surface charge (pHPZC = 7.7). Parameters, including initial pH, DOX concentration, and ionic strength, that influenced the DOX adsorption capacity of KOH-BPB were examined. Adsorption equilibrium of DOX on KOH-BPB was assessed through four isothermal models: the Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich models. The obtained data were most compatible with the Langmuir model (R² = 0.9879). KOH-BPB has a maximum DOX absorption capacity of 121.95 mg g<SUP>-1</SUP> which exceeds that of many comparable absorbents. The maximum DOX removal was 96.7% at pH 6, a DOX concentration of 20 mg L<SUP>-1</SUP>, and a KOH-BPB dose of 1.0g L<SUP>-1</SUP>. These findings reveal that biochar from banana peel effectively removes antibiotic residues from water. This study provides a potential, low-cost, and environmentally friendly adsorbent.
Artocarpus nigrifolius: Cytotoxic and Antibacterial Constituents
Tran Minh Hoi,김영호,Ha Van Anh,Nguyen Thi Thanh Huong,Nguyen Van Tuyen,Le Thi Tu Anh,Nguyen Thanh Tra,Ba Thi Cham,Nguyen Thi Thu Ha,Pham Thuy Linh,Doan Duy Tien,Phan Van Kiem,Ninh Khac Ban,Lidziya Kukha 한국응용생명화학회 2013 Applied Biological Chemistry (Appl Biol Chem) Vol.56 No.6
Six known compounds including α-amyrin 3-acetate (1), β-sitosterol (2), betulinic acid (3), friedelan-3-one (4),artochamin B (5), and 2-C-methyl-D-erythritol 4-O-α-D-glucopyranoside (6) were isolated from the stem barks and leaves of Artocarpus nigrifolius (Moraceae) for the first time. Their structures were identified by spectroscopic methods as well as comparison with literatures. Cytotoxicity and antibacterial activity of 1-6 were evaluated. Results showed that artochamin B (5)possessed the highest cytotoxicity towards MCF7, Lu, HepG2,and KB cell lines with IC50 values of 4.59, 20.00, 3.60, and 1.18μg/mL, respectively. It also inhibited the growth of Gram-positive bacteria (Bacillus subtilis, Staphylococcus aureus), whereas inactive on the growth of both Gram-negative bacteria and yeast.
Artocarpus nigrifolius: Cytotoxic and Antibacterial Constituents
Hoi, Tran Minh,Anh, Ha Van,Huong, Nguyen Thi Thanh,Tuyen, Nguyen Van,Anh, Le Thi Tu,Tra, Nguyen Thanh,Cham, Ba Thi,Ha, Nguyen Thi Thu,Linh, Pham Thuy,Tien, Doan Duy,Kiem, Phan Van,Ban, Ninh Khac,Kukha The Korean Society for Applied Biological Chemistr 2013 Applied Biological Chemistry (Appl Biol Chem) Vol.56 No.6
Six known compounds including ${\alpha}$-amyrin 3-acetate (1), ${\beta}$-sitosterol (2), betulinic acid (3), friedelan-3-one (4), artochamin B (5), and 2-C-methyl-D-erythritol 4-O-${\alpha}$-D-glucopyranoside (6) were isolated from the stem barks and leaves of Artocarpus nigrifolius (Moraceae) for the first time. Their structures were identified by spectroscopic methods as well as comparison with literatures. Cytotoxicity and antibacterial activity of 1-6 were evaluated. Results showed that artochamin B (5) possessed the highest cytotoxicity towards MCF7, Lu, HepG2, and KB cell lines with $IC_{50}$ values of 4.59, 20.00, 3.60, and $1.18{\mu}g/mL$, respectively. It also inhibited the growth of Gram-positive bacteria (Bacillus subtilis, Staphylococcus aureus), whereas inactive on the growth of both Gram-negative bacteria and yeast.
Anh-Tuan Le,Nguyen Duy Ha,Chong-Oh Kim,Jang-Roh Rhee,Nguyen Chau,Nguyen Quang Hoa,Nguyen Duc Tho,Heebok Lee 한국자기학회 2006 Journal of Magnetics Vol.11 No.1
The effect of annealing temperature on the permeability and giant magneto-impedance (GMI) behaviors of Fe68.5Mn5Si13.5B9Nb₃Cu₁ amorphous alloy has been systematically investigated. The nan℃rystalline Fe68.5Mn5- Si13.5B9Nb3Cu1 alloys consisting of ultra-fine (Fe,Mn)₃Si grains embedded in an amorphous matrix were obtained by annealing their precursor alloy at the temperature range from 500℃ to 600℃ for 1 hour in vacuum. The permeability and GMI profiles were measured as a function of external magnetic field. It was found that the increase of both the permeability and the GMI effect with increasing annealing temperature up to 535℃ was observed and ascribed to the ultrasoft magnetic properties in the sample, whereas an opposite tendency was found when annealed at 600℃ which is due to the microstructural changes caused by high-temperature annealing. The study of temperature dependence on the permeability and GMI effect showed some insights into the nature of the magnetic exchange coupling between nan℃rystallized grains through the amorphous boundaries in nan℃rystalline magnetic materials.
Hoan Minh Tran,Tam Huu Nguyen,Viet Quoc Nguyen,Phuc Huynh Tran,Linh Duy Thai,Thuy Thu Truong,Le-Thu T. Nguyen,Ha Tran Nguyen 한국고분자학회 2019 Macromolecular Research Vol.27 No.1
The photoswitching poly(pyrene-1-ylmethyl-methacrylate-random-methyl methacrylate-random-methacrylate spirooxazine) was synthesized via atom transfer radical polymerization and characterized by proton nuclear magnetic resonance (1H NMR), gel permeation chromatography (GPC), Fourier transform infrared (FTIR) spectroscopy, UV-visible spectroscopy, and differential scanning calorimetry (DSC). The obtained copolymer exhibited the capability of erasable and rewritable photoimaging, making it a potential candidate for optical data storage materials. Moreover, the copolymer also showed the sensing ability for cyanide anions effect in aqueous solutions.