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Results 51-60 of 206 (Search time: 0.001 seconds).
  • Authors: Luis A. Miccio; Claudia, Borredon; Ulises, Casado;  Advisor: -;  Co-Author: - (2022)

    The analysis of structural relaxation dynamics of polymers gives an insight into their mechanical properties, whose characterization is used to qualify a given material for its practical scope. The dynamics are usually expressed in terms of the temperature dependence of the relaxation time, which is only available through time-consuming experimental processes following polymer synthesis. However, it would be advantageous to estimate their dynamics before synthesizing them when designing new materials. In this work, we propose a combined approach of artificial neural networks and the elastically collective nonlinear Langevin equation (ECNLE) to estimate the temperature dependence of the main structural relaxation time of polymers based only on the knowledge of the chemical structure ...

  • Authors: Pham, Kim Ngoc; Trung, Kien Mac; Huu, Tuan Nguyen;  Advisor: -;  Co-Author: - (2022)

    In the present work, we have reported the dye removal efficiency of Cobalt chromite, CoCr2O4 nanoparticles synthesized via the solvothermal method. The obtained CoCr2O4 nanoparticles demonstrated that the dye removal efficiency of CoCr2O4 nanoparticles could be enhanced by a reduction of size or improved water dispersibility. The pseudo-second-order kinetic model best describes the adsorption of Congo red (CR) dye on CoCr2O4 nanoparticles. The Langmuir adsorption isotherm model fitted best for the adsorption process and the adsorption capacity for CCO@450 and CCO@550 nanoparticles were found to be 59.4 and 43.8 mg g−1, respectively. Dye adsorption studies on a mixture of CR, MB, and RhB dyes solution revealed that the MB removal efficiency of CoCr2O4 nanoparticles could improve to 8...

  • Authors: Vinh-Hung Tran; Tat-Tai Truong; Khac-Khanh Bui; Hong-Ky Le;  Advisor: -;  Co-Author: - (2022)

    Mechanical elements with freeform surfaces are very common in aerospace, automotive, mold and die industries. With increasing demand for higher quality of freeform surfaces in many different applications, quality monitoring and evaluation of freeform surfaces have become of great concern in modern manufacturing. In this study, quality evaluation of a freeform surface manufactured by CNC milling was carried out. First, the point cloud data of a given freeform surface sample manufactured by stamping were acquired by using different scanning systems, namely HandySCAN 3D 700 and ATOS Compact Scan 5M. Based on the point cloud data, the toolpaths, including roughing, semi-finishing, and finishing, were generated using computer-aided manufacturing (CAM) software. Milling experiments were t...

  • Authors: Nguyen, Tuan Anh; Nguyen, Ngoc Huyen; Ngo, Xuan Dinh;  Advisor: -;  Co-Author: - (2022)

    In this study, we have investigated the influence of crystallinity, phase ratio, and heterojunction formation on the sensing performance of ZnO/ZnFe2O4 (ZnO/ZFO) nanocomposite-based electrochemical sensors for the detection of furazolidone (FZD) antibiotic drug. Results obtained show that the crystallinity and phase ratio of ZnO/ZFO nanocomposites have decisive effects on their electron transfer and active site density. Tuning the crystallinity and ZnO content of ZnO/ZFO nanocomposites is an effective way to enhance the FZD electrochemical sensing performance. Findings from this research suggested that the formation of ZnO/ZFO heterojunction could significantly improve their electrochemical responses for FZD due to arising of the internal electric field and redistribution of Zn2+, F...

  • Authors: Huan Thanh, Duong; Hieu Chi, Phan; Tien Thinh, Le;  Advisor: -;  Co-Author: - (2022)

    Functionally Graded Materials (FGM) is the advanced material that covers the advantages of both metal and ceramic which contain FGM. Due to the perfect combination, FGM plate is widely developed with the requirement for the practical application to avoid the difficulties from conventional approaches. Consequently, the study establishes the database from analytical model and uses it for developing a machine learning model in the desire of finding an alternative model to predict critical buckling load of the plate. Such a machine learning model is crucial for predicting critical buckling load of the FGM plate without complexity of analytical developments or finite element resources. The Gaussian Process Regression model has been developed based on the database containing 1000 labeled ...

  • Authors: Cao, H. Nam;  Advisor: -;  Co-Author: - (2022)

    By applying the island rule proposed recently, we compute the entanglement entropy of Hawking radiation and study the Page curve for the eternal black holes in massive gravity. We investigate for both the neutral and charged black holes which the corresponding results of Schwarzschild and Reissner–Nordström black holes are restored in the limit of massless graviton. We show for the neutral and non-extremal charged black holes that the island is not formed at the early times of the evaporation and hence the entanglement entropy increases linearly in time. However, for the extremal charged black hole, the calculation of the entanglement entropy at the early times without the island is ill-defined because the metric is divergent at the curvature singularity. This implies that new physi...

  • Authors: David, Wai Lun Ng; Abel, Duarte Alonso; Alessandro, Bressan;  Advisor: -;  Co-Author: - (2022)

    The purpose of this study is to build an understanding of how firms operate under the COVID-19 crisis. Specifically, the study examines the significance of firms’ survival for their surrounding community, business–community relations during this severe situation and factors helping firms address this unprecedented challenge. The conceptual tenets of stakeholder theory are considered.

  • Authors: Nguyen, Khong Van; Vu, Le Anh; Thoan Tran, Van; Trung, Tran Anh; Vu, Nguyen Hoang;  Advisor: -;  Co-Author: - (2022)

    Research, development and application of alternative fuels are common approaches in many countries around the world to reduce dependence on fossil fuels, to improve energy security as well as to decrease environmental pollution such as the greenhouse gas emission. The use of biodiesel fuels as an alternative fuel for petroleum diesel fuel is very effective for the reduction of CO2 emission, because biodiesel is produced from renewable biomass resources. However, there are a few of the using biodiesel research on CRDI (Common Rail Direct Injection) diesel engine. This paper describes a real time CRDI diesel engine 2.5TCI-A HYUNDAI STAREX simulations with blends of palm oil derived biodiesel and diesel using Matlab simulink software. The results show small deviation from cylinder pres...

  • Authors: Minh, Huy Le; Hong Ha, Thi Vu; Dabin, Wang; Jinyi, Lee;  Advisor: -;  Co-Author: - (2022)

    This article presents a cylinder-type magnetic camera (CMC) system in nondestructive testing (NDT) of a heat exchanger (HX) tube. The CMC system is developed for the inspection of corrosion on HX tubes of nuclear power plants. The CMC probe works based on the principle of eddy current testing, in which a single-large bobbin coil is used to supply eddy current on the tube, and a matrix array of InSb Hall sensor is used to measure the electromagnetic field around the corrosion. The CMC system can measure both the real and imaginary components of the magnetic field. The CMC system can operate in two modes: single-line scan mode by selecting a single-line Hall sensor or area scan mode by the electrical scan. The limitations and advantages of each operation mode will be presented. The CM...

  • Authors: Elsisi, M.; Minh, Quang Tran; Vu, Thi Lien; Nguyen, Thi Thanh Nga;  Advisor: -;  Co-Author: - (2022)

    Managing procedure for charging and discharging battery system plays an essential contributor in improving the performance of energy storage system for example increment of utilizing batteries. This paper aims to develop a new hybrid genetic algorithm-based proportional integral (GA-based PI) controller with an adaptive neuro-fuzzy inference system (ANFIS) for the charging balance of batteries. The dataset is generated by using the GA-based PI controller, then a training strategy is introduced for the ANFIS controller. The proposed approach is evaluated by the GA-based PI controller and the PI controller based on Ziegler Nichols method