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Damage assessment of laminated composite beam structures using damage locating vector （DLV） method

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Frontiers of Structural and Civil Engineering 2015年第4期9卷 457-465页

作者： t. vo-duy Division of Computational Mathematics and Engineering (CME) Institute for Computational Science (INCOS) Ton Duc ThangUniversity Hochiminh City Vietnam Division of Construction Computation (DCC) Institute for Computational Science (INCOS) Ton Duc Thang University HochiminhCity vietnam Faculty of Civil Engineering Ton Duc Thang University Hochiminh City Vietnam

In this paper, the damage locating vector (DLV) method using normalized cumulative energy (nce) is employed to locate multiple damage sites in laminated composite beam structures. Numerical simulations of two laminated composite beams are employed to investigate several damage scenarios in which the degradation of elements is modeled by the reduction in the longitudinal Young’s modulus and transverse Young’s modulus of beam layers. the results show that the DLV method gives good performance for this kind of structure.

关键词： damage locating vector method (DLV) laminated composite beam structure normalized cumulative energy structural health monitoring (SHM)

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the use of the node-based smoothed finite element method to estimate static and seismic bearing capacities of shallow strip footings

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Journal of Rock Mechanics and Geotechnical Engineering 2022年第1期14卷 180-196页

作者： H.C.Nguyen t.vo-Minh Department of civil and environmental engineering imperial college londonuk Department of civil engineering and industrial design university of liverpoolliverpooluk Faculty of civil engineering ho chi minh city university of technology(hutech)ho chi minh cityviet nam

the node-based smoothed finite element method(NS-FEM)is shortly presented for calculations of the static and seismic bearing capacities of shallow strip footings.A series of computations has been performed to assess variations in seismic bearing capacity factors with both horizontal and vertical seismic *** results obtained agree very well with those using the slip-line method,revealing that the magnitude of the seismic bearing capacity is highly dependent upon the combinations of various directions of both components of the seismic *** upward vertical seismic acceleration reduces the seismic bearing capacity compared to the downward vertical seismic acceleration in *** addition,particular emphasis is placed on a separate estimation of the effects of soil and superstructure inertia on each seismic bearing capacity *** the effect of inertia forces arising in the soil on the seismic bearing capacity is non-trivial,and the superstructure inertia is the major contributor to reductions in the seismic bearing *** tables and charts are given for practical application to the seismic design of the foundations.

关键词： Limit analysis Node-based smoothed finite element method(NS-FEM) Second-order cone programming(SOCP) Seismic bearing capacity Strip footing

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Bubble-enhanced quadrilateral finite element formulation for nonlinear analysis of geotechnical problems

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Underground Space 2018年第3期3卷 229-242页

作者： t.Vu-Hoang t.vo-Minh H.Nguyen-Xuan Department of Civil Engineering HCMC University of TechnologyHo Chi Minh CityViet Nam Department of Civil Engineering Hutech UniversityHo Chi Minh CityViet Nam Center for Interdisciplinary Research in technology Hutech UniversityHo Chi Minh CityViet Nam

We investigate a new numerical procedure based on a bubble-enriched finite element formulation in combination with the implicit backward Euler scheme for nonlinear analysis of strip footings and stability of *** soil body is modeled as a perfect plastic Mohr-Coulomb *** displacement field is approximated by a 4-node quadrilateral element discretization enhanced with bubble *** loads and failure mechanisms in cohesive frictional soil are determined by solving a few Newton-Raphson *** results of the present approach are verified by both analytical solutions and other numerical solutions available in the literature.

关键词： Material nonlinear analysis Backward Euler scheme Bearing capacity Slope stability Bubble functions Finite elements

Mental health around retirement:evidence of Ashenfelter’s dip

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Global Health Research and Policy 2023年第1期8卷 184-199页

作者： thang t.vo tran t.Phu-duyen Health and Agricultural Policy Research Institute 279 Nguyen Tri PhuongDistrict 1072406 Ho Chi Minh CityVietnam School of Economics University of Economics HCMC279 Nguyen Tri PhuongDistrict 1072406 Ho Chi Minh CityVietnam

Background Mental health issues among retirees have become increasingly concerning because the aging population presents a significant challenge globally,particularly in Western *** studies on this issue are plagued with bias owing to lacking panel data and estimation *** study investigated the depression levels of European adults around the time of *** We used data obtained from Waves 1-7 of the Survey of Health,Ageing,and Retirement in Europe(SHARE)to create panel data covering the 2004-2017 *** 3(SHARELIFE)was excluded from the sample because it provided mismatched ***-effects(FE)and fixed-effects instrumental variables(FE-IV)models with multiple imputations were employed to examine the impacts of retirement on mental health before and after retirement,where being over pension age(normal and early)was used as the instrument *** Our results indicated that retirement based on aspirational motivations(β=−0.115,ptive circumstances(β=−0.038,ptly reduced depression,whereas retiring under negative circumstances could deteriorate one’s mental health(β=0.087,pted that overall,retiring reduced retirees’depression(β=−0.096,ptively).the results of FE-IV models showed that adults planning to retire in the next two years experienced less depression compared with others in the workforce(λ=−0.313,pthese adults must have adjusted their lifestyles in response to their impending retirement,thereby evincing Ashenfelter’s *** years after retirement,when the“honeymoon”phase was over,retirees may have completely adapted to their new lives and the effect of retirement was no longer *** Retirement improves mental health before it happens,but not *** the pension eligibility age may postpone the beneficial effects of retirement on ***,policy implications should be

关键词： Retirement Mental health Instrumental variable SHARE Panel data Ashenfelter’s dip

Dialkyl imidazolium acetate ionosilica as efficient and recyclable organocatalyst for cyanosilylation reactions of ketones

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Green Energy & Environment 2020年第2期5卷 130-137页

作者： thanh tran duy Alysson Duarte Rodrigues Giang vo-thanh Peter Hesemann Institut de Chimie Moléculaire et des Matériaux D'Orsay UniversitéParis-SaclayUMR 818291405 Orsay CedexFrance Institut Charles Gerhardt de Montpellier Universitéde MontpellierUMR 5253 CNRS-UM-ENSCMPlace E.Bataillon34000 MontpellierFrance

We report new heterogeneous organocatalyst based on silica hybrid supported N-heterocyclic carbene(NHC-)*** organocatalyst is formed from an imidazolium iodide based ionosilica material,followed by iodide/acetate anion *** imidazolium acetate generates the organocatalytic carbene via partial deprotonation of the imidazolium ring in *** monitored via EDX,solid state NMR and ion chromatography measurements,the iodide/acetate exchange involving the imidazolium ionosilica material took place only in small *** the fact that the exchanged material contains only a very small amount of acetate,we observed good catalytic activity and recyclability in cyanosilylation reactions of ketones with trimethylsilyl *** versatility of the catalyst was highlighted via reaction with several substrates,yielding the corresponding cyanohydrins in good *** recycling experiments,the material showed decreasing catalytic activity starting from the third reaction cycle,but high catalytic activity can be regenerated via another acetate *** work is important as it highlights the possibility to combine carbene chemistry and silica,which are antagonistic at a first *** show that imidazolium acetate based ionosilicas are therefore heterogeneous'proto-carbenes',and that there is no need to form strongly basic silica supported NHCs to obtain heterogeneous *** work therefore opens the route towards heterogeneous and re-usable NHC-organocatalysts from supported ionic liquid imidazolium acetates.

关键词： N-heterocyclic carbenes Ionosilica Heterogeneous organocatalysis Cyanosilylation Ionic liquids

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Enhancement of water absorption capacity and compressibility of hydrogel sponges prepared from gelatin/chitosan matrix with different polyols

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Progress in Natural Science:Materials International 2022年第1期32卷 54-62页

作者： thi Sinh vo tran thi Bich Chau vo trung tien tran Nhan duy Pham School of Mechanical Engineering Sungkyunkwan University Department of Industrial Management Can Tho University Department of Chemistry Memorial University of Newfoundland

the hydrogel sponges have prepared successfully from gelatin/chitosan(GEL/CtS) matrix with different polyols basing on scanning electron microscopy(SEM) and Fourier-transform infrared spectroscopy(FtIR) analysis. the results indicate that the compressibility and thermal properties(thermal gravimetric analysis, tGA) were improved significantly with adding the different polyols [poly(vinyl alcohol)-PVA, and poly(ethylene glycol)-poly(propylene glycol)-poly(ethylene glycol) – PEPEG] into GEL/CtS matrix. Specially, the as-prepared hydrogel sponges with superabsorbent behavior were also investigated with the attained water absorption capacity to 605 g gand 585 g gfor GCV＿1/1/0.3 and GCE＿1/1/0.3 sponges, respectively, as well as the excellent water absorption capacity in a wide range of p H and salt concentration. Hence, these studies demonstrated that the hydrogel sponges are concerned as potential and promising candidates to apply especially in the fields of biomedicine and hygiene.

关键词： Hydrogel sponges Absorbent Chitosan Polyols Gelatin Water absorption capacity

Incorporation of hydroxyapatite in crosslinked gelatin/chitosan/poly(vinyl alcohol) hybrids utilizing as reinforced composite sponges, and their water absorption ability

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Progress in Natural Science:Materials International 2021年第5期31卷 664-671页

作者： thi Sinh vo tran thi Bich Chau vo truong Sinh Nguyen Nhan duy Pham School of Mechanical Engineering Sungkyunkwan University Department of Chemistry Memorial University of Newfoundland Department of Industrial Management Can Tho University

the crosslinked gelatin/chitosan/poly(vinyl alcohol)/hydroxyapatite(GEL/CtS/PVA/HAp, GCPH) sponges were fabricated by a freeze-drying method to yield the reinforced composite sponges with proper features. the porosity value and pore size of the crosslinked GCPH sponges reached ～80% and 50–100 μm, respectively, which can be an appropriate range to allow cells to migrate into the reinforced composite sponges in the tissue engineering technology. Besides, the proper bonding presence between HAp particles and the crosslinked polymeric matrix or the crosslinked network formation between the polymers were also proved through fourier-transform infrared spectroscopy(FtIR), X-ray diffraction(XRD) and thermal gravimetric(tG/DtG) analysis. Owing to incorporation of HAp particles and good distribution of HAp particles inside the crosslinked polymeric matrix, their mechanical properties were improved through the determination of compression tests. Concomitantly, their water absorption ability reached effectively in both the distilled water and Na Cl solution, and their recovery also maintained well for 10 absorbing–squeezing cycles to be considered as an effective reusability for the crosslinked sponge ***, the crosslinked GCPH sponge prepared in the present study can become a potential candidate to apply especially in the biomedical/medical applications and tissue engineering technology.

关键词： Reinforced composite sponge Gelatin Chitosan Poly(vinyl alcohol) Hydroxyapatite Water absorption ability Reusability

A combination of damage locating vector method （DLV） and differential evolution algorithm （DE） for structural damage assessment

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Frontiers of Structural and Civil Engineering 2018年第1期12卷 92-108页

作者： t. NGUYEN-tHOI A. tRAN-VIEt N. NGUYEN-MINH t. vo-duy V. HO-HUU Division of Computational Mathematics and Engineering Institute for Computational Science Ton Duc Thang University Hochiminh City Vietnam Division of Construction Computation Institute for Computational Science Ton Duc Thang University Hochiminh City Vietnam Faculty of Civil Engineering Ton Duc Thang University Hochiminh City Vietnam

In this study, a two-stage method is presented for identifying multiple damage scenarios. In the first stage, the damage locating vector （DLV） method using normalized cumulative energy （nce） is employed for damage localization in structures. In the second stage, the differential evolution algorithm （DE） is used for damage severity of the structures. In addition, in the second stage, a modification of an available objective function is made for handing the issue of symmetric structures. to verify the effectiveness of the present technique, numerical examples of a 72-bar space truss and a one-span steel portal frame are considered. In addition, the effect of noise on the performance of the identification results is also investigated. the numerical results show that the proposed combination gives good assessment of damage location and extent for multiple structural damage cases.

关键词： damage assessment damage locating vector method (DLV) differential evolution (DE) multiple damagelocation assurance criterion (MDLAC) mode shape error function

Integrating Machine Learning and Evidential Reasoning for User Profiling and Recommendation

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Journal of Systems Science and Systems Engineering 2023年第4期32卷 393-412页

作者： toan Nguyen Mau Quang-Hung Le Duc-Vinh vo duy Doan Van-Nam Huynh University of Information technology Ho Chi Minh CityVietnam Vietnam National University Ho Chi Minh CityVietnam Department of Information technology Quy Nhon UniversityQuy NhonVietnam Ho Chi Minh City University of Banking Ho Chi Minh CityVietnam School of Knowledge Science Japan Advanced Institute of Science and TechnologyIshikawaJapan

User profiles representing users’preferences and interests play an important role in many applications of personalized *** the rapid growth of social platforms,there is a critical need for efficient solutions to learn user profiles from the information they shared on social platforms so as to improve the quality of recommendation *** problem of user profile learning is significantly challenging due to difficulty in handling data from multiple sources,in different formats and often associated with *** this paper,we introduce an integrated approach that combines advanced Machine Learning techniques with evidential reasoning based on Dempster-Shafer theory of evidence for user profiling and *** developed methods for user profile learning and multi-criteria collaborative filtering are demonstrated with experimental results and analysis that show the effectiveness and practicality of the integrated approach.A proposal for extending multi-criteria recommendation systems by incorporating user profiles learned from different sources of data into the recommendation process so as to provide better recommendation capabilities is also highlighted.

关键词： Machine learning Dempster-Shafer theory of evidence user profiles personalized recommendation preferences