An efficient approach for model updating of a large-scale cable-stayed bridge using ambient vibration measurements combined with a hybrid metaheuristic search algorithm

Tran N. Hoa,S. Khatir,G. De Roeck,Nguyen N. Long,Bui T. Thanh,M. Abdel Wahab 국제구조공학회 2020 Smart Structures and Systems, An International Jou Vol.25 No.4

This paper proposes a novel approach to model updating for a large-scale cable-stayed bridge based on ambient vibration tests coupled with a hybrid metaheuristic search algorithm. Vibration measurements are carried out under excitation sources of passing vehicles and wind. Based on the measured structural dynamic characteristics, a finite element (FE) model is updated. For long-span bridges, ambient vibration test (AVT) is the most effective vibration testing technique because ambient excitation is freely available, whereas a forced vibration test (FVT) requires considerable efforts to install actuators such as shakers to produce measurable responses. Particle swarm optimization (PSO) is a famous metaheuristic algorithm applied successfully in numerous fields over the last decades. However, PSO has big drawbacks that may decrease its efficiency in tackling the optimization problems. A possible drawback of PSO is premature convergence leading to low convergence level, particularly in complicated multi-peak search issues. On the other hand, PSO not only depends crucially on the quality of initial populations, but also it is impossible to improve the quality of new generations. If the positions of initial particles are far from the global best, it may be difficult to seek the best solution. To overcome the drawbacks of PSO, we propose a hybrid algorithm combining GA with an improved PSO (HGAIPSO). Two striking characteristics of HGAIPSO are briefly described as follows: (1) because of possessing crossover and mutation operators, GA is applied to generate the initial elite populations and (2) those populations are then employed to seek the best solution based on the global search capacity of IPSO that can tackle the problem of premature convergence of PSO. The results show that HGAIPSO not only identifies uncertain parameters of the considered bridge accurately, but also outperforms than PSO, improved PSO (IPSO), and a combination of GA and PSO (HGAPSO) in terms of convergence level and accuracy.

The K\"{a}hler Different of a Set of Points in~$\pmpn$

Nguyen T. Hoa,Tran N. K. Linh,Le N. Long,Phan T. T. Nhan,Nguyen T. P. Nhi 대한수학회 2022 대한수학회보 Vol.59 No.4

Given an ACM set $\X$ of points in a multiprojective space $\pmpn$ over a field of characteristic zero, we are interested in studying the K\"ahler different and the Cayley-Bacharach property for $\X$. In $\bbP^1\times \bbP^1$, the Cayley-Bacharach property agrees with the complete intersection property and it is characterized by using the K\"ahler different. However, this result fails to hold in $\pmpn$ for $n>1$ or $m>1$. In this paper we start an investigation of the K\"ahler different and its Hilbert function and then prove that $\X$ is a complete intersection of type $(d_1,\ldots,d_m,d'_1,\ldots,d'_n)$ if and only if it has the Cayley-Bacharach property and the K\"ahler different is non-zero at a certain degree. We characterize the Cayley-Bacharach property of $\X$ under certain assumptions.

Promoting Higher Education Cooperation between the European Union and Asia: The Case of Vietnam

( Chau T. M. Ly ),( Thuy T. T. Nguyen ),( Uyen T. Nguyen ),( Long T. Nguyen ) 한국EU학회 2019 Asia-Pacific Journal of EU Studies Vol.17 No.1

With regards to the cooperation between European countries and Asia in higher education Higher Education is a top priority both for Europe and the Vietnamese Government. In the context of Vietnam, Vietnam-European Union universities cooperation gets more opportunities for bilateral and multilateral cooperation on joint-training programmes, collaborative research projects, students and lecturers exchange programmes and exchange scholarships. There has also been more cooperation under research projects funded under ERASMUS. The paper summaries the higher education cooperation between European and Asia focusing the case of Vietnam, raised the challenges in terms of partner universities and the contributions of the cooperation regarding the mobility partnerships to enhancing the international cooperation capacity of the higher education institutions involved and reinforcing the capacity and internationalisation of higher education thus contributing also to raising the prestige and international recognition. The paper presents the impact of European cooperation programmes in Vietnam and concludes some remarks to promote the higher education cooperation between Europe and Asia.

Ag-doped graphitic carbon nitride photocatalyst with remarkably enhanced photocatalytic activity towards antibiotic in hospital wastewater under solar light

Nguyen Le Minh Tri,김지태,Bach Long Giang,T.M. Al Tahtamouni,Pham Thi Huong,이창하,Nguyen Minh Viet,Do Quang Trung 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.80 No.-

In this study a novel Ag-doped graphitic carbon nitride (g-C3N4) photocatalyst was synthesized and appliedas high efficientmaterial under solarlight towardsemerging antibiotic pollutantin hospital wastewater. Thetetracycline (TC) was chosen as a target pollutant and the content of Ag doping at 3 mmol revealed thehighest photocatalytic degradation efficiency of TC (96.8%) after 120 min under solar light irradiation. Thephotoluminescence and UV–vis analysis confirmed the enhancement of charge separation and transfer inthe graphitic carbon structure after Ag-doping. The removal efficiency of TC using g-C3N4 and Ag-doped g-C3N4 (AgCN) underdark conditions was only 25.6 and 31.8%, respectively. While under solarlight conditions,the removal efficiency of TC increased to 68.3 and 96.8% for g-C3N4 and AgCN, respectively. The reusabilityprocess showed that AgCN displayed extremely high stability after 6 cycles without significant drop inantibiotic degradation efficiency. The application of AgCN was tested for treatment of TC from hospitalwastewater and it showed high removal efficiency of 89.6% within 120 min reaction time. In addition, theintermediatesgeneratedandreductionof total organiccarbon(TOC)duringthephotocatalyticreactionweredetected to support information of possible TC removal mechanism.

Multi-Criteria Decision Making Using Preferential Selection Index in Titanium based Die-Sinking PMEDM

Nguyen Huu-Phan,Banh Tien-Long,Le Quang-Dung,Nguyen Duc-Toan,T. Muthuramalingam Korean Society for Precision Engineering 2019 한국정밀공학회지 Vol.36 No.9

A novel and cost-effective method for high-throughput 3D culturing and rhythmic assessment of hiPSC-derived cardiomyocytes using retroreflective Janus microparticles

Huyen T. M. Pham,Duc Long Nguyen,Hyo‑Sop Kim,Yang Eun Kyeong,김재호,윤현철,박현지 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Background Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) gain attention as a potent cell source in regenerative medicine and drug discovery. With the necessity of the demands for experimental models to create a more physiologically relevant model of the heart in vitro we herein investigate a 3D culturing platform and a method for assessing rhythm in hiPSC-CMs. Methods The 3D cell culture PAMCELL™ plate is designed to enable cells to attach exclusively to adhesive patterned areas. These cell adhesive zones, named as micro-patterned pads, feature micron silica beads that are surfacemodified with the well-known arginyl-glycyl-aspartic acid (RGD) peptide. RGD binding to the surface of hiPSC-CMs facilitates cell–cell attachment and the formation of uniform-size spheroids, which is controlled by the diameter of the micro-patterned pads. The assessment and evaluation of 3D hiPSC-CMs beating pattern are carried out using reflective properties of retroreflective Janus micro-particle (RJP). These RJPs are modified with an antibody targeting the gap junction protein found on the surface of hiPSC-CM spheroids. The signal assessment system comprises a camera attached to an optical microscope and a white light source. Results The 3D PAMCELL™ R100 culture plate efficiently generate approximately 350 uniform-sized hiPSC-CM spheroids in each well of a 96-well plate and supported a 20-day culture. Analysis of genes and protein expression levels reveal that iPSC-CM spheroids grown on PAMCELL™ R100 retain cardiac stem cell characteristics and functions, outperforming traditional 2D culture platform. Additionally, the RJPs enable monitoring and evaluation of in vitro beating properties of cardiomyocytes without using complex monitoring setup. The system demonstrates its capability to identify alteration in the rhythmic activity of cardiac cells when exposed to ion channel blockers, nifedipine and E4031.

Highly Conductive Polymers Paired with Nanostructured Carbon Frame for the Application of Energy Storage

Omar T. Melton,Young-Gi Kim,Wafaa Abousamra,Dan Yang,June-Ho Jung,Sabina Besic,Michael Birschbach,Von Ebron,Ramil Mercado,Patrick J. Kinlen,Hai-Long Nguyen 한국고분자학회 2016 한국고분자학회 학술대회 연구논문 초록집 Vol.41 No.2

Optimal Pricing for Duopoly in Cognitive Radio Networks: Cooperate or not Cooperate?

Do, Cuong T.,Tran, Nguyen H.,Zhu Han,Long Bao Le,Sungwon Lee,Choong Seon Hong IEEE 2014 IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS Vol.13 No.5

<P>Pricing is an effective approach for spectrum access control in cognitive radio (CR) networks. In this paper, we study the pricing effect on the equilibrium behaviors of selfish secondary users' (SUs') data packets which are served by a CR base station (BS). From the SUs' point of view, a spectrum access decision on whether to join the queue of the BS or not is characterized through an individual optimal strategy that is joining the queue with a joining probability. This strategy also requires each SU to know the average queueing delay, which is a non-trivial problem. Toward this end, we provide queueing delay analysis by using the M/G/1 queue with breakdown. From the BS's point of view, we consider a duopoly market based on the two paradigms: the opportunistic dynamic spectrum access (O-DSA) and the mixed O-DSA & dedicated dynamic spectrum access (D-DSA). In the first paradigm, two co-located opportunistic-spectrum BSs utilize freely spectrum-holes to serve SUs. Then, we show the advantages of the cooperative scenario due to the unique solution that can be obtained in a distributed manner by using the dual decomposition algorithms. For the second paradigm, there are one opportunistic-spectrum BS and one dedicated-spectrum BS. We study a price competition between two BSs as a Stackelberg game. The cooperative behavior between two BSs is modeled as a bargaining game. In both paradigms, bargain revenues of the cooperation are always higher than those due to competition in both cases. Extensive numerical analysis is used to validate our derivation.</P>

Controllable synthesis and visible-active photocatalytic properties of Au nanoparticles decorated urchin-like ZnO nanostructures

Chi H. Le,Oanh T.T. Nguyen,Hieu S. Nguyen,Long D. Pham,Chung V. Hoang 한국물리학회 2017 Current Applied Physics Vol.17 No.11

Urchin-like nanostructures of ZnO were synthesized by one-step hydrothermal method and their morphology was optimized via the hydrothermal temperature - the key parameter in controlling the morphologies of the ZnO materials. The photoabsorbance of the urchin-like ZnO nanomaterials was expanded from the intrinsic UV absorption range to the visible region by depositing the plasmonic Au nanoparticles (AuNPs) on the ZnO surface. The synthesized visible-active AuNPs-ZnO urchin-like composite material showed an excellent photocatalytic activity. As a result of the shape effect, the impact of the AuNPs on the photocatalytic activity of the urchin-like ZnO is found to increase about 30% in comparison to that of the reported conventional ZnO nanorods.

Effect of thermolysis condition on characteristics and nonsteroidal anti-inflammatory drugs (NSAIDs) absorbability of Fe-MIL-88B-derived mesoporous carbons

Van Tran, Thuan,Nguyen, Duyen Thi Cam,Le, Hanh T.N.,Bach, Long Giang,Vo, Dai-Viet N.,Dao, To-Uyen T.,Lim, Kwon Taek,Nguyen, Trinh Duy Elsevier 2019 Journal of environmental chemical engineering Vol.7 No.5

<P><B>Abstract</B></P> <P>Discharge of nonsteroidal anti-inflammatory drugs (NSAIDs) from wastewater has been increasingly alarmed, led to the advent of the treatment techniques. Among these methods, adsorption is regarded as a tunable and green approach with the utilization of mesoporous carbon (MC) as an efficient and recyclable adsorbent. Herein, we described the strategy for the synthesis of novel MC from Fe-MIL-88B as a self-sacrificial template. Three thermolysis temperatures (550, 750, and 950 °C) were investigated to compare the structural characteristics and absorbability towards selected NSAIDs compounds including diclofenac sodium (DCF), aspirin (APR), and ibuprofen (IBU). Effect of contact time (0–480 min), concentration (10–40 mg/L), pH (2–10), and MC dosage (0.1–0.5 g/L) was systematically studied. Kinetic and isotherm models were also used to find out the adsorption mechanism and behavior of NSAIDs pharmaceutical over MC materials. Proposed mechanism and recyclability test were rigorously studied to gain more insight into how the NSAIDs molecules adsorb on the MC materials and their potential towards drug treatment.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Effect of thermolysis temperature on characteristics and absorbability towards anti-inflammatory drugs was conducted. </LI> <LI> Kinetic, isotherm, and recyclability experiments were systematically studied. </LI> <LI> Adsorption mechanisms including H-bond, π–π interaction, metal–oxygen bridging, and electrostatic attraction were rigorously proposed. </LI> <LI> Outstanding adsorption capacity (∼144 mg/g), and excellent reusability were monitored with Fe-MIL-88B-derived mesoporous carbon. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>