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A Review of Electrically-Assisted Manufacturing
Huu-Duc Nguyen-Tran,오현석,홍성태,한흥남,Jian Cao,안성훈,천두만 한국정밀공학회 2015 International Journal of Precision Engineering and Vol.2 No.4
The mechanical properties of metals change temporarily or permanently under application of electric currents under deformation. This phenomenon is often referred to as electroplasticity. The electroplasticity of metals and their alloys has been investigated under various loading conditions including tensile, compressive, bending, and hardness tests. Electrically-assisted manufacturing (EAM) utilizes this electroplasticity in manufacturing processes. Due to its technical advantages such as enhanced formability and reduced springback, EAM is energy efficient with reduced process time. Recent developments in EAM include various bulk deformation and sheet metal forming processes. This paper summarizes previously reported electroplastic behaviors of various metals or metal alloys and recent EAM processes. In addition, contemporary EAM patents are briefly reviewed.
Nguyen Duc Anh,Pham Van Thanh,Doan Tu Lap,Nguyen Tuan Khai,Tran Van An,Tran Duc Tan,Nguyen Huu An,Dang Nhu Dinh 한국인터넷정보학회 2022 KSII Transactions on Internet and Information Syst Vol.16 No.2
Forest fires inflict great losses of human lives and serious damages to ecological systems. Hence, numerous fire detection methods have been proposed, one of which is fire detection based on sensors. However, these methods reveal several limitations when applied in large spaces like forests such as high cost, high level of false alarm, limited battery capacity, and other problems. In this research, we propose a novel forest fire detection method based on image processing and correlation coefficient. Firstly, two fire detection conditions are applied in RGB color space to distinguish between fire pixels and the background. Secondly, the image is converted from RGB to YCbCr color space with two fire detection conditions being applied in this color space. Finally, the correlation coefficient is used to distinguish between fires and objects with fire-like colors. Our proposed algorithm is tested and evaluated on eleven fire and non-fire videos collected from the internet and achieves up to 95.87% and 97.89% of F-score and accuracy respectively in performance evaluation.
Le-Phuc Nguyen,Yen Thi Hai Pham,Phuong Thuy Ngo,Tri Van Tran,Loc Vinh Tran,Nam Thi Hoai Le,Luong Huu Nguyen,Tung Thanh Dang,Duc Anh Nguyen,Marco Wenzel,David Hartmann,Karsten Gloe,Jan J. Weigand,Klaus 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.5
Acid leaching and a two-step solvent extraction procedure were developed to produce high purity mixture of La and Ce from iron-rich spent FCC catalyst discharged from Dzung Quat refinery (Vietnam). Acid leaching of the spent catalyst with 2M HNO3 and a solid-to-liquid ratio of 1/3 at 80 oC in 1 h dissolved almost 90% of La while 12% of Al and 25% of Fe were transferred to the leachate. The extraction of RE metals and main impurities such as Al and Fe by a mixture of di-2-ethylhexyl phosphoric acid (D2EHPA) and tributyl phosphate (TBP) was investigated. Experiments showed that it was necessary to remove Fe before extracting RE and the optimum extraction conditions for a high recovery of RE while 0% of Al extraction were pH1, contact time=10min, and D2EHPA/TBP volume ratio= 4 : 1. At these conditions, the extraction yields of La(III) and Ce(III) were 72% and 89%, respectively. A two-step solvent extraction was developed to achieve a high purity of RE mixture, which included (1) the removal of impurity Fe by 25% (v/v) diisooctyl phosphinic acid (DiOPA) in n-octane for 140 min, (2) the extraction of rare earths by a mixture of di-2-ethylhexyl phosphoric acid (D2EHPA) and tributyl phosphate (TBP) in n-octane for 10 min without the need for adjusting the pH of the leaching solution.
Nhung Thanh Thi Truong,Tam Huu Nguyen,Bao Kim Doan,Le-Thu T. Nguyen,Tam Hoang Luu,Chau Duc Tran,Thiet Quoc Nguyen,Ha Tran Nguyen 한국고분자학회 2021 Macromolecular Research Vol.29 No.11
In this research, three organic photocatalysts, 4-(4H-dithieno[3,2-b:2',3'- d]pyrrol-4-yl)-N,N-diphenylaniline, 4-(pyren-1-yl)-4H-dithieno[3,2-b:2',3'-d]pyrrole and 4-(6b,10-dihydroperylen-3-yl)-4H-dithieno[3,2-b:2',3'-d]pyrrole have been successfully synthesized through C-N coupling reactions. The chemical structures and the optical properties of the obtained organic photocatalysts have been characterized via 1H NMR,13C NMR, elemental analysis, and UV-Vis spectroscopy. Next, these dithieno[3,2-b:2′,3′-d]pyrrole-based photocatalysts have been used for the polymerization of methyl methacrylate, 2-(dimethylamino)ethyl methacrylate and tert-butyl methacrylate monomers under 365 nm UV irradiation, resulting in (meth)acrylate polymers with controlled molecular weights and low polydispersity indexes.
Melvyn WB Zhang,Bach Xuan Tran,Huong Lan Thi Nguyen,Huong Thi Le,Nguyen Hoang Long,Huong Thi Le,Nguyen Duc Hinh,Tran Dinh Tho,Bao Nguyen Le,Vu Thi Minh Thuc,Chau Ngo,Nguyen Huu Tu,Carl A. Latkin,Roger 대한의료정보학회 2017 Healthcare Informatics Research Vol.23 No.2
Objectives: The average alcohol consumption per capita among Vietnamese adults has consistently increased. Although alcoholrelated disorders have been extensively studied, there is a paucity of research shedding light on this issue among Internet users. The study aimed to examine the severity of alcohol-related disorders and other associated factors that might predispose individuals towards alcohol usage in a sample of youths recruited online. Methods: An online cross-sectional study was conducted with 1,080 Vietnamese youths. A standardized questionnaire was used. Respondent-driven sampling was applied to recruit participants. Multivariate logistic and Tobit regressions were utilized to identify the associated factors. Results: About 59.5% of the males and 12.7% of the total youths declared that they were actively using alcohol. From the total sample, a cumulative total of 32.3% of the participants were drinking alcohol, with 21.8% and 25.0% of the participants being classified as drinking hazardously and binge drinkers, respectively. The majority of the participants (60.7%) were in the pre-contemplative stage. Conclusions: A high prevalence of hazardous drinking was recognized among online Vietnamese youths. In addition, we found relationships between alcohol use disorder and other addictive disorders, such as tobacco smoking and water-pipe usage. Our results highlighted that the majority of the individuals are not receptive to the idea of changing their alcohol habits, and this would imply that there ought to be more government effort towards the implementation of effective alcohol control policies.
Magnetocaloric Effect in Fe-Ni-Zr Alloys Prepared by Using the Rapidly-quenched Method
Nguyen Huy Dan,Nguyen Huu Duc,Tran Dang Thanh,Nguyen Hai Yen,Ngac An Bang,Do Thi Kim Anh,판더롱,유성초 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.62 No.12
Fe90−xNixZr10 (x = 0, 5, 10, 15, 20 and 25) ribbons with various thicknesses were prepared byusing a melt-spinning technique. The Curie temperature, TC, of the alloys dramatically decreasedfrom 960 K to room temperature at high quenching rates. When the alloys had an amorphousstructure, their TC strongly depended on the Ni concentration. The maximum entropy change,|Sm|max, with H = 12 kOe, of the alloys was around 1 J·kg−1K−1 at room temperature. Onthe other hand, the full width at half maximum the entropy-change peak was quite large, 85 K,which was suitable for applications in magnetic refrigerators at room temperature.