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An electrochemical and microstructural characterization of steel-mortar admixed with corrosion inhibitors

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Science China(Technological Sciences) 2009年第1期52卷 52-66页

作者： tuan anh Nguyen Recep AVCI Corrosion and Sustainable Infrastructure Laboratory Western Transportation InstitutePO Box 174250College of Engineering Montana State University Bozeman Imaging and Chemical Analysis Laboratory Department of Physics Montana State University Bozeman

The present research brings new insights on the role of admixed corrosion inhibitors in the processes of cement hydration and rebar corrosion. The admixing of NaCl and the corrosion inhibitors in fresh mortar was found to alter the morphology and microstructure of the hardened mortar at the steel-mortar interfacial region. The admixing of the inhibitors increased the risk of carbonation of cement hydrates at the steel-mortar interfacial region, but partially displaced chloride ions. Chloride and the admixed inhibitors facilitated the formation of different cement hydrates and affected chloride binding at the steel-mortar interfacial region. The admixing of all three inhibitors was found to increase the polarization resistance of steel, indicating reduced corrosion rate of the steel over 48-day exposures to salt ponding.

关键词： corrosion inhibitor rebar corrosion steel-mortar interface FESEM EDX XPS EIS

An Efficient Differential Evolution for Truss Sizing Optimization Using AdaBoost Classifier

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Computer Modeling in Engineering & Sciences 2023年第1期134卷 429-458页

作者： Tran-Hieu Nguyen anh-tuan Vu Hanoi University of Civil Engineering Hanoi100000Vietnam

Design constraints verification is the most computationally expensive task in evolutionary structural optimization due to a large number of structural analyses thatmust be *** a surrogatemodel to approximate the behavior of structures instead of the exact structural analyses is a possible solution to tackle this ***,most existing surrogate models have been designed based on regression *** paper proposes a novel method,called CaDE,which adopts a machine learning classification technique for enhancing the performance of the Differential Evolution(DE)*** proposed method is separated into two *** the first optimization stage,the original DE is implemented as usual,but all individuals produced in this phase are stored as inputs of the training *** on design constraints verification,these individuals are labeled as“safe”or“unsafe”and their labels are saved as outputs of the training *** collecting enough data,an AdaBoost model is trained to evaluate the safety state of *** model is then used in the second stage to preliminarily assess new individuals,and unpromising ones are rejected without checking design *** method reduces unnecessary structural analyses,thereby shortens the optimization *** benchmark truss sizing optimization problems are solved using the proposed method to demonstrate its *** obtained results show that the CaDE finds good optimal designs with less structural analyses in comparison with the original DE and four other DE *** reduction rate of five examples ranges from 18 to over 50%.Moreover,the proposed method is applied to a real-size transmission tower design problem to exhibit its applicability in practice.

关键词： Structural optimization machine learning surrogate model differential evolution AdaBoost classifier

DEVELOPING AN ENERGY BENCHMARKING SYSTEM FOR HOTEL BUILDINGS USING THE STATISTICAL METHOD AND THE SIMULATION-BASED APPROACH

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Journal of Green Building 2019年第3期14卷 3-22页

作者： anh tuan Nguyen David Rockwood the Faculty of Architecture University of Science and Technology–The University of DanangViet Nam School of Architecture University of HawaiiU.S.A

Due to increased tourist activity,many cities now have a large number of hotel *** is necessary to establish measures to evaluate energy use intensity to effectively manage energy consumption in this *** study uses a combined strategy to establish an energy benchmark for hotel buildings in ***,a survey and analysis of actual building stock data of 50 hotels in Danang,Vietnam,was *** survey-based benchmark and its related data was then used to build a reference energy model to estimate an energy benchmark for other climatic regions in Vietnam by using the energy simulation *** results reveal that the average energy use intensity for hotels in Danang was 87.4 kWh/*** or 8628.6 kWh/***,this study proposes that because of the differing expectations of comfort standards,hotels of different grades should have separate *** study also proposes an energy intensity-based rating scale,including 7 grades from the least energy intensive(grade A)to the most energy intensive(grade G),which can be used to manage,label,or encourage sustainable energy use in hotel *** relationship between the energy use intensity and the occupancy rate of the hotels was reported,compared,and *** was found that occupancy rate has no significant impact on the energy use *** the survey result,some predictive models were developed to estimate annual energy consumption of hotel buildings based on their *** simulated benchmarks for other regions were also *** results demonstrate many potential applications in the management,design and construction,and renovation of this building type.

关键词： energy benchmarking hotel energy use intensity energy labeling energy rating scale simulation-based benchmarking

Spherical Fuzzy WASPAS-based Entropy Objective Weighting for International Payment Method Selection

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Computers, Materials & Continua 2022年第7期72卷 2055-2075页

作者： Phi-Hung Nguyen Thanh-tuan Dang Kim-anh Nguyen Hong-anh Pham Faculty of Business FPT UniversityHanoi100000Vietnam Department of Business Management National Taipei University of TechnologyTaipei1068Taiwan Department of Industrial Engineering and Management National Kaohsiung University of Science and TechnologyKaohsiung80778Taiwan

In international trade,exporters prefer to receive payments as quickly as possible,and importers want to make payments as late as *** this respect,the payment field,an essential condition for trade transactions,also represents the positions of exporters and importers *** addition,there are many cases in which various variables must be considered rather than only one specific variable representatively affecting payment,particularly in the case of import-export Small and Medium-Sized Enterprises(SMEs)from emerging countries.A selection of proper payment methods can be categorized as a Multi-Criteria Decision-Making(MCDM)***,this study aims to propose a novel and efficient Spherical Fuzzy Weighted Aggregated Sum Product Assessment based Entropy Objective Weighting method(SF-EW and WASPAS-SF)to evaluate international payment methods with uncertain ***,SF-EW model is applied to determine the relative weights of critical ***,international payment method alternatives are prioritized by the WASPAS-SF *** essential factors for four international payment methods are proposed based on experts’opinions and the existing literature.A real-world case study from Vietnamese import-export SMEs is presented to validate the applicability of the proposed *** results indicated that“Characteristics of payment method(PA)”had the most significant impact on international payment method *** comparison,“Letters of Credit(L/C)”was the most reliable payment method with the highest ranking available to international ***,a sensitivity analysis was performed to examine the validity and robustness of the proposed decision support ***,this study could contribute to international payment services and in the context of globalization and international trade.

关键词： International payment Vietnam MCDM spherical fuzzy theory entropy WASPAS

Effect of silica forms in rice husk ash on the properties of concrete

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International Journal of Minerals,Metallurgy and Materials 2012年第3期19卷 252-258页

作者： Le anh-tuan Bui Chun-tsun Chen Chao-lung Hwang Department of Construction Engineering Taiwan University of Science and Technology

The strength and durability properties of concrete with or without three types of rice husk ash （RHA）, namely, amorphous, partial crystalline, and crystalline RHA, were investigates. The three types of RHA were added into concrete at a 20% replacement level. Consequently, the pozzolanic reactivity of amorphous RHA was higher than that of partial crystalline and crystalline RHA. Concrete added with amorphous RHA showed excellent characteristics in its mechanical and durability properties. The results showed that the higher the amount of crystalline silica in RHA, the lower the concrete resistivity value became. When compared with each other, concretes with 20% of the ce- ment replaced with these types of RHA achieved similar ultrasonic pulse velocity values, but all were lower than that of the control concrete. The incorporation of these kinds of RHA significantly reduced chloride penetration. The results not only encourage the use of amorphous materials, they also support the application of crystalline or partial crystalline RHA as mineral and pozzolanic admixtures for cement.

关键词： rice husk ash silica concrete compressive strength durability waste management

Real-time security margin control using deep reinforcement leamning

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Energy and AI 2023年第3期13卷 52-63页

作者： Hannes Hagmar Robert Eriksson Le anh tuan Chalmers University of Technology Gothenburg 41296Sweden Svenska kraftnat(Swedish National Grid) Sundbyberg 17224Sweden

This paper develops a real-time control method based on deep reinforcement learning aimed to determine the optimal control actions to maintain a sufficient secure operating *** secure operating limit refers to the limit to the most stressed pre-contingency operating point of an electric power system that can withstand a set of credible contingencies without violating stability *** developed deep reinforcement learning method uses a hybrid control scheme that is capable of simultaneously adjusting both discrete and continuous action *** performance is evaluated on a modified version of the Nordic32 test *** results show that the developed deep reinforcement learning method quickly learns an effective control policy to ensure a sufficient secure operating limit for a range of different system *** performance is also compared to a control based on a rule-based look-up table and a deep reinforcement learning control adapted for discrete action *** hybrid deep reinforcement learning control managed to achieve significantly better on all of the defined test sets,indicating that the possibility of adjusting both discrete and continuous action variables resulted in a more flexible and efficient control policy.

关键词： Deep reinforcement learning Preventive control Proximal policy optimization Secure operating limit

Measurement investigation on the feasibility of shallow geothermal energy for heating and cooling applied in agricultural greenhouses of Shouguang City: Ground temperature profiles and geothermal potential

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Information Processing in Agriculture 2021年第2期8卷 251-269页

作者： anh tuan Le Liang Wang Yang Wang Daoliang Li National Innovation Center for Digital Fishery China Agricultural UniversityBeijing 100083China Beijing Engineering and Technology Research Centre for Internet of Things in Agriculture Beijing 100083China Key Laboratory of Agricultural Information Acquisition Technology Ministry of AgricultureBeijing 100083China College of Information and Electrical Engineering China Agricultural UniversityBeijing 100083China Department of Electronics Nam Dinh University of Technology EducationNam Dinh 07000Viet Nam

The use of electrical energy for heating and cooling systems to control the temperature in greenhouses will lead to high production and product *** solve this problem,shallow geothermal energy as a local source of energy could be *** this study,a measurement model,the distribution profiles of temperature,and a preliminary assessment of the geothermal potential in the shallow zone at depths of 0.1 m to 3.6 m in Shouguang City,Shandong Province,eastern China were *** measurement results showed that the annual average temperature at depths of 0.1–3.6 m ranged from 13.1℃ to 17.6℃.Preliminary assessment results of the geothermal potential showed that the daily average temperature difference between the air and at depths of 1.5–3.6 m was mainly from 10℃ to 25℃ during the winter months and between-15℃ and-5℃ during the summer ***,the heating systems could operate during January,February,November,and *** May,June,and July,the cooling systems could be ***,the measurement model gave good stability results,and it could be used in combination with the monitoring of the groundwater table,a survey of the thermal conductivity of the soil,climate change studies,which helps reduce unnecessary time and costs.

关键词： Ground temperature profile Geothermal energy Ground heat exchanger Measurement model Shouguang

Regularization of the Inverse Problem for Time Fractional Pseudo-parabolic Equation with Non-local in Time Conditions

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Acta Mathematica Sinica,English Series 2022年第12期38卷 2199-2219页

作者： Nguyen Duc PHUONG Le Dinh LONG anh tuan NGUYEN Dumitru BALEANU Faculty of Fundamental Science Industrial University of Ho Chi Minh CityVietnam Division of Applied Mathematics Science and Technology Advanced InstituteVanLang UniversityHoChi Minh CityVietnam Faculty of Technology Van Lang UniversityHo Chi Minh CityVietnam Department of Mathematics Cankaya UniversityAnkaraTurkey Lebanese AmericanUniversity BeirutLebanon Institute of Space Sciences Magurele-BucharestRomania

This paper is devoted to identifying an unknown source for a time-fractional diffusion equation in a general bounded ***,we prove the problem is non-well posed and the stability of the source ***,by using the Modified Fractional Landweber method,we present regularization solutions and show the convergence rate between regularization solutions and sought solution are given under a priori and a posteriori choice rules of the regularization parameter,***,we present an illustrative numerical example to test the results of our theory.

关键词： Source problem fractional pseudo-parabolic problem ill-posed problem convergence estimates regularization

Assessment of different machine learning techniques in predicting the compressive strength of self-compacting concrete

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Frontiers of Structural and Civil Engineering 2022年第7期16卷 928-945页

作者： Van Quan TRAN Hai-Van Thi mai Thuy-anh NGUYEN Hai-Bang LY Faculty of Civil Engineering University of Transport TechnologyHanoi 100000Vietnam

The compressive strength of self-compacting concrete(SCC)needs to be determined during the construction design *** paper shows that the compressive strength of SCC(CS of SCC)can be successfully predicted from mix design and curing age by a machine learning(ML)technique named the Extreme Gradient Boosting(XGB)algorithm,including non-hybrid and hybrid *** ML techniques,such as Linear regression(LR),K-Nearest Neighbors(KNN),Support Vector Machine(SVM),Decision Trees(DTR),Random Forest(RF),Gradient Boosting(GB),and Artificial Neural Network using two training algorithms LBFGS and SGD(denoted as ANN_LBFGS and ANN_SGD),are also compared with the XGB ***,the hybrid models of eight ML techniques and Particle Swarm Optimization(PSO)are constructed to highlight the reliability and accuracy of SCC compressive strength prediction by the XGB_PSO hybrid *** highest number of SCC samples available in the literature is collected for building the ML *** with previously published works’performance,the proposed XGB method,both hybrid and non-hybrid models,is the most reliable and robust of the examined techniques,and is more accurate than existing ML methods(R2=0.9644,RMSE=4.7801,and MAE=3.4832).Therefore,the XGB model can be used as a practical tool for engineers in predicting the CS of SCC.

关键词： compressive strength self-compacting concrete machine learning techniques particle swarm optimization extreme gradient boosting