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Engine performance and combustion characteristics of a direct injection compression ignition engine fueled waste cooking oil synthetic diesel

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International Journal of Coal Science & Technology 2020年第3期7卷 560-570页

作者： Thanh Viet nguyen Khanh Duc nguyen Nang xuan Ho Vinh Duy nguyen Department of Internal Combustion Engine School of Transportation EngineeringHanoi University of Science and TechnologyHanoiViet Nam Faculty of Vehicle and Energy Engineering Phenikaa UniversityYen NghiaHa-Dong DistrictHanoiViet Nam

Biodiesels produced from various feedstocks have been considered as alternative fuels used in internal combustion engines without major *** research focuses on producing biodiesel from waste cooking oil(WCOSD)by the catalytic cracking method using MgO as the catalyst and comparing the engine operating characteristics of the test engine when using WCOSD and traditional diesel(CD)as test *** a result,the brake power of the test engine fueled WCOSD,and traditional diesel is ***,the engine fuel consumption in the case of using WCOSD is slight increases in some operating ***,the nitrogen oxides emissions of the test engine fueled WCOSD are higher than those of CD at all tested *** trend is opposite for hydrocarbon emission as the HC emission of the engine fueled by WCOSD reduces 26.3%on *** smoke emission of the test engine in case of using WCOSD is lower 17%on average than that of ***,the carbon monoxide emissions are lower at the low and medium loads and higher at the full *** results show that the new biodiesel has the same characteristics as those of commercial biodiesel and can be used as fuel for diesel engines.

关键词： Feedstock Waste cooking oil Engine characteristics Exhaust missions Ignition timing Fuel consumption

Three-Dimensional Meshfree Analysis of Interlocking Concrete Blocks for Step Seawall Structure

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Computers, Materials & Continua 2021年第1期66卷 165-178页

作者： Hau nguyen-Ngoc Hnguyen-xuan Magd Abdel-Wahab Soete Laboratory Faculty of Engineering and ArchitectureGhent UniversityTechnologiepark Zwijnaarde 903B-9052ZwijnaardeBelgium University of Science and Technology The University of DanangDa Nang CityVietnam CIRTech Institute Ho Chi Minh City University of TechnologyHo Chi Minh CityVietnam Division of Computational Mechanics Ton Duc Thang UniversityHo Chi Minh CityVietnam Faculty of Civil Engineering Ton Duc Thang UniversityHo Chi Minh CityVietnam

This study adapts the flexible characteristic of meshfree method in analyzing three-dimensional(3D)complex geometry structures,which are the interlocking concrete blocks of step *** elastostatic behavior of the block is analysed by solving the Galerkin weak form formulation over local support *** 3D moving least square(MLS)approximation is applied to build the interpolation functions of *** pre-defined number of nodes in an integration domain ranging from 10 to 60 nodes is also investigated for their effect on the studied *** accuracy and efficiency of the studied method on 3D elastostatic responses are validated through the comparison with the solutions of standard finite element method(FEM)using linear shape functions on tetrahedral elements and the well-known commercial software,*** results show that elastostatic responses of studied concrete block obtained by meshfree method converge faster and are more accurate than those of standard *** studied meshfree method is effective in the analysis of static responses of complex geometry *** amount of discretised nodes within the integration domain used in building MLS shape functions should be in the range from 30 to 60 nodes and should not be less than 20 nodes.

关键词： Meshfree method local support domain moving least square shape function 3D elastostatic behavior complex geometry

Novel Soft ComputingModel for Predicting Blast-Induced Ground Vibration in Open-Pit Mines Based on the Bagging and Sibling of Extra Trees Models

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Computer Modeling in Engineering & Sciences 2023年第3期134卷 2227-2246页

作者： Quang-Hieu Tran Hoang nguyen xuan-Nam Bui Department of Surface Mining Mining FacultyHanoi University of Mining and GeologyHanoi100000Vietnam Innovations for Sustainable and Responsible Mining(ISRM)Research Group Hanoi University of Mining and GeologyHanoi100000Vietnam

This study considered and predicted blast-induced ground vibration(PPV)in open-pit mines using bagging and sibling techniques under the rigorous combination of machine learning ***,four machine learning algorithms,including support vector regression(SVR),extra trees(ExTree),K-nearest neighbors(KNN),and decision tree regression(DTR),were used as the base models for the purposes of combination and PPV initial *** bagging regressor(BA)was then applied to combine these base models with the efforts of variance reduction,overfitting elimination,and generating more robust predictive models,abbreviated as BA-ExTree,BAKNN,BA-SVR,and *** is emphasized that the ExTree model has not been considered for predicting blastinduced ground vibration before,and the bagging of ExTree is an innovation aiming to improve the accuracy of the inherently ExTree model,as *** addition,two empirical models(i.e.,USBM and Ambraseys)were also treated and compared with the bagging models to gain a comprehensive *** this aim,we collected 300 blasting events with different parameters at the Sin Quyen copper mine(Vietnam),and the produced PPV values were also *** were then compiled as the dataset to develop the PPV predictive *** results revealed that the bagging models provided better performance than the empirical models,except for the BA-DTR *** those,the BA-ExTree is the best model with the highest accuracy(i.e.,88.8%).Whereas,the empirical models only provided the accuracy from 73.6%–76%.The details of comparisons and assessments were also presented in this study.

关键词： Mine blasting blast-induced ground vibration environmentally friendly blasting peak particle velocity bagging extra trees

Assessment of Livelihood Vulnerability to Drought: A Case Study in Dak Nong Province, Vietnam

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International Journal of Disaster Risk Science 2019年第4期10卷 604-615页

作者： nguyen Thi Thanh Thao Dao nguyen Khoi Tran Thanh xuan Bernard Tychon Universite de Liege 6700 ArlonBelgium Institute for Environmental Science Engineeringand ManagementIndustrial University of Ho Chi Minh CityHo Chi Minh CityVietnam Institute of Research and Development Duy Tan UniversityDa NangVietnam Faculty of Environment University of ScienceVietnam National University Ho Chi Minh CityHo Chi Minh CityVietnam NTT Institute of Hi-Technology Nguyen Tat Thanh UniversityHo Chi Minh CityVietnam

In recent years,droughts have strongly affected the Central Highlands of Vietnam and have resulted in crop damage,yield decline,and serious water *** study investigated the livelihood vulnerability of five communities of farmers who are exposed to droughts in one of the more vulnerable regions of Vietnam—Dak Nong Province.A survey of 250 households was conducted in the five communities to collect data on the region’s sociodemographic profile,livelihood systems,social networks,health status,food and water security,drought conditions,and climate *** were aggregated using a livelihood vulnerability index and the IPCC vulnerability *** survey results indicate that Quang Phu community is the most vulnerable of the study’s communities,followed by Nam N’dir,Dak Nang,Duc Xuyen,and Dak D’ro in descending order of *** availability and livelihood strategies are the most important variables in determining the vulnerability of the five surveyed *** order to reduce vulnerability to droughts,water management practices and livelihood diversification in farming and nonfarming activities are recommended for the study area.

关键词： Agricultural drought Livelihood vulnerability Vietnam Vulnerability indicators

Predicting rock size distribution in mine blasting using various novel soft computing models based on meta-heuristics and machine learning algorithms

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Geoscience Frontiers 2021年第3期12卷 458-472页

作者： Chengyu Xie Hoang nguyen xuan-Nam Bui Yosoon Choi Jian Zhou Thao nguyen-Trang School of Environment and Resources Xiangtan UniversityXiangtan 411105China Institute of Research and Development Duy Tan UniversityDa Nang 550000Viet Nam Department of Surface Mining Mining FacultyHanoi University of Mining and Geology18 Pho VienDuc Thang wardBac Tu Liem districtHanoi 100000Viet Nam Center for Mining Electro-Mechanical researchHanoi University of Mining and Geology18 Pho VienDuc Thang wardBac Tu Liem districtHanoi 100000Viet Nam Department of Energy Resources Engineering Pukyong National UniversityBusan 48513Republic of Korea School of Resources and Safety Engineering Central South UniversityChangsha 410083HunanChina Division of Computational Mathematics and Engineering Institute for Computational ScienceTon Duc Thang UniversityHo Chi Minh City 700000Viet Nam Faculty of Mathematics and Statistics Ton Duc Thang UniversityHo Chi Minh City 700000Viet Nam

Blasting is well-known as an effective method for fragmenting or moving rock in open-pit *** evaluate the quality of blasting,the size of rock distribution is used as a critical criterion in blasting operations.A high percentage of oversized rocks generated by blasting operations can lead to economic and environmental ***,this study proposed four novel intelligent models to predict the size of rock distribution in mine blasting in order to optimize blasting parameters,as well as the efficiency of blasting operation in open ***,a nature-inspired algorithm(i.e.,firefly algorithm-FFA)and different machine learning algorithms(i.e.,gradient boosting machine(GBM),support vector machine(SVM),Gaussian process(GP),and artificial neural network(ANN))were combined for this aim,abbreviated as FFA-GBM,FFA-SVM,FFA-GP,and FFA-ANN,***,predicted results from the abovementioned models were compared with each other using three statistical indicators(e.g.,mean absolute error,root-mean-squared error,and correlation coefficient)and color intensity *** developing and simulating the size of rock in blasting operations,136 blasting events with their images were collected and analyzed by the Split-Desktop *** which,111 events were randomly selected for the development and optimization of the ***,the remaining 25 blasting events were applied to confirm the accuracy of the proposed ***,blast design parameters were regarded as input variables to predict the size of rock in blasting ***,the obtained results revealed that the FFA is a robust optimization algorithm for estimating rock fragmentation in bench *** the models developed in this study,FFA-GBM provided the highest accuracy in predicting the size of fragmented *** other techniques(i.e.,FFA-SVM,FFA-GP,and FFA-ANN)yielded lower computational stability and ***,the FFA-GBM model can be used as a powerful

关键词： Mine blasting Rock fragmentation Artificial intelligence Hybrid model Gradient boosting machine Meta-heuristic algorithm

THE C_M-EMBEDDED PROBLEM AND OPTIMALITY CONDITIONS

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Acta Mathematicae Applicatae Sinica 1990年第1期6卷 22-34页

作者：夏尊铨 STRODIOT J.-J. nguyen V.hien Facultes Universitaires N.D.de la Paix Facultes Universitaires N.D.de la Paixn this paper the C_M-embedded problem which is also called the design centering problem inother papers will be described and new optimality conditions and some results associated withoptimality conditions will be presented. These results hold for general non-convex regions. To acertain extent they provide the possibility to develop search techniques. It should be pointed outthat in this paper the only case where the Minkowski norm is just the Euclidean norm is treated.

In this paper the C_M-embedded problem which is also called the design centering problem inother papers will be described, and new optimality conditions and some results associated withoptimality conditions will be presented. These results hold for general non-convex regions. To acertain extent they provide the possibility to develop search techniques. It should be pointed outthat, in this paper, the only case where the Minkowski norm is just the Euclidean norm is treated.

关键词： Optimality Condition Euclidean Norm Search Technique Math Application Minkowski Norm

Implementation aspects of a phase-field approach for brittle fracture

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Frontiers of Structural and Civil Engineering 2019年第2期13卷 417-428页

作者： G.D.HUYNH X.,ZHUANG H.nguyen-xuan Institute of Continuum Mechanics Leibniz-Universitat Hannover30167 HannoverGermany Center for Interdisciplinary Research in Technology Ho Chi Minh CityUniversity of Technology (HUTEH)Ho Chi Minh City Vietnam

This paper provides a comprehensive overview of a phase-field model of fracture in solid mechanics setting. We start reviewing the potential energy governing the whole process of fracture including crack initiation, branching or merging. Then, a discretization of system of equation is derived, in which the key aspect is that for the correctness of fracture phenomena, a split into tensile and compressive terms of the strain energy is performed, which allows crack to occur in tension, not in compression. For numerical analysis, standard finite element shape functions are used for both primary fields including displacements and phase field. A staggered scheme which solves the two fields of the problem separately is utilized for solution step and illustrated with a segment of Python code.

关键词： phase-field modeling FEM staggered scheme fracture

Effect of Poly-Alkylene-Glycol Quenchant on the Distortion, Hardness, and Microstructure of 65Mn Steel

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Computers, Materials & Continua 2021年第6期67卷 3249-3264页

作者： Thi xuan Tran xuan Phuong nguyen Duong Nam nguyen Dinh Toai Vu Minh Quang Chau Osamah Ibrahim Khalaf Anh Tuan Hoang Hanoi University of Science and Technology HanoiVietnam Ho Chi Minh City University of Transport Ho Chi Minh CityVietnam Vietnam Maritime University HaiphongVietnam Industrial University of Ho Chi Minh City(IUH) Ho Chi Minh CityVietnam Al-Nahrain Nanorenewable Energy Research Center Al-Nahrain UniversityBaghdadIraq Ho Chi Minh city University of Technology(HUTECH) Ho Chi Minh CityVietnam

Currently,the 65Mn steel is quenched mainly by oil *** though the lower cooling rate of oil compared to water reduces the hardness of steel post quenching,the deforming and cracking of parts are often *** the other hand,the oil media also has the disadvantage of being ammable,creating smoke that adversely affects the *** poly alkylene glycol(PAG)polymer quenchant is commonly used for quenching a variety of steels based on its advantages such as non-ammability and exible cooling rate subjected to varying concentration and stirring *** article examines the effect of PAG polymer quenching solution(with concentrations of 10%and 20%)on deformation,hardness,and microstructure of C-ring samples made of 65Mn ***,the performance of PAG polymer quenchant is also compared with those of two common quenching solutions:Water and *** cooling in water,the C-ring samples had the largest deformation and 2 times higher than the results obtained when a 10%PAG solution was *** particular,similar levels of deformation on the C-ring samples were observed in both cases of 20%PAG solution and oil as the primary quenching ***,the hardness level measured between the sampled parts quenched in the 20%PAG solution appeared to be more uniform than that obtained from the oil-quenched *** study of the microscopic structure of steel by optical microscopy combined with X-ray diffraction showed that the water hardened sample exhibited cracks and comprised of two phases,martensite and retained *** to the results of Electron Back Scattering Diffraction(EBSD)analysis and backscattering electronic image(BSE),the content of austenite residue in the sample when the sample was cooled in PAG 10 and 20%solution was 3.21%and 4.73%,respectively and smaller than the measurements obtained from oil quenching ***,the 65Mn steel is cooled in 20%PAG solution for high hardness and more evenly distributed than when it is q

关键词： Polyethylene glycol electron backscattering diffraction quenching media cooling rate backscattering electronic image

A Correlation Coefficient Approach for Evaluation of Stiffness Degradation of Beams Under Moving Load

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Computers, Materials & Continua 2019年第7期61卷 27-53页

作者： Thanh Q.nguyen Thao T.D.nguyen H.nguyen-xuan Nhi K.Ngo Laboratory of Applied Mechanics(LAM) Ho Chi Minh City University of TechnologyHo Chi Minh City740030Vietnam Saigon Hi-Tech Park Training Center Ho Chi Minh City715650Vietnam Ho Chi Minh City Department of Transportation and Communication Ho Chi Minh City710100Vietnam CIRTECH Institute Ho Chi Minh City University of Technology(HUTECH)Ho Chi Minh City717349Vietnam Department of Physical Therapy Graduate Institute of Rehabilitation ScienceChina Medical UniversityTaichung40402Taiwan

This paper presents a new approach using correlation and cross-correlation coefficients to evaluate the stiffness degradation of beams under moving *** theoretical study of identifying defects by vibration methods showed that the traditional methods derived from the vibration measurement data have not met the needs of the actual *** show that the correlation coefficients allow us to evaluate the degree and the effectiveness of the defects on *** the same time,the cross-correlation model is the basis for determining the relative position of *** results of this study are experimentally conducted to confirm the relationship between the correlation coefficients and the existence of the *** particular,the manuscript shows that the sensitivity of the correlation coefficients and cross-correlation is much higher than the parameters such as changes in stiffness(EJ)and natural frequency values(Δf).This study suggests using the above parameters to evaluate the stiffness degradation of beams by vibration measurement data in practice.

关键词： Correlation coefficient cross-correlation vibration signal vibration amplitude frequency