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Scouring of a granular bed by dam break: Experimental study and numerical simulation by a VOF-LPT coupling

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International Journal of Sediment Research 2023年第3期38卷 432-445页

作者： Quyen Thi Le nguyen Viet dung nguyen Patrice Coorevits EPROAD Research Unit University of Picardie Jules Verne IUT of Aisne Hanoi University of Civil Engineering

The first part of the research reported here consists of an experimental campaign to study the scouring of a granular bed(glass beads, sand) induced by a dam break in an open channel. Two configurations are considered: with and without cylinders. In the second part of this study, the volume of fluid method coupled with the shear stress transport turbulent model and the lagrangian particle tracking method is used to simulate the local scour processes. The four-way coupling is realized by considering the drag force and collisions between particles. Using a vortex map and velocity profiles, the flow dynamics and scour pattern can be studied. The current research also focuses on the profiles of the erodible particle bed and the sediment transport rate to study the effects of a cylinder on local scour. The presence of the cylinder increases the experimental erosion depth by up to 42%. It was found that for relatively close particle diameters(2 and 3 mm), a granular bed with larger porosity(larger diameter) erodes the *** and numerically it was found that the center of the granular bed experiences more erosion compared to the channel sides. In the last part of the research, comparisons between the numerical results and the experimental data allowed risk areas to be identified and the roles of porosity,sediment density, and flow dynamics on erosion to be identified.

关键词： Volume of fluid Lagrangian particle tracking Scour Granular bed Cylinder Dam break

Study of relationship between motion of mechanisms in gas operated weapon and its shock absorber

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Defence Technology（防务技术） 2024年第3期33卷 42-54页

作者： Jiri Balla Roman Vitek dung nguyen Van Zbynek Krist Hung nguyen Van Department of Weapons and Ammunition University of Defence BrnoCzech Republic Department of Weapons Le Quy Don Technical UniversityHanoiViet Nam Department of Design and Special Engineering Alexander Dubcek University of TrencinSlovakia

The article deals with the motion of the breech block carrier and the weapon casing of an automatic weapon mounted on a flexible carriage and the base of the *** works,which did not consider the dynamic properties of the base of the weapon,did not allow to reconcile the calculated and experimental results of the weapon casing displacement when shooting from firing *** the analysis of the motion of individual parts,the methods of mathematical modelling and firing experiments using a high-speed camera were *** show the best accord with experiment when modelling the system with 4 degrees of *** oscillation of the system regarding the movement of the breech block carrier and the weapon casing was investigated under changed conditions of rate of fire,the use of a muzzle brake and different types of shock *** velocities and displacements of the weapon casing and the breech block carrier at different values of the impulse of the gases to the breech block carrier were determined.

关键词： Shock absorber Gas-operated weapon Force-impulse diagram Recoil system Breech block carrier

Element-wise representations with ECNet for material property prediction and applications in high-entropy alloys

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npj Computational Materials 2022年第1期8卷 2409-2418页

作者： Xinming Wang nguyen-dung Tran Shuming Zeng Cong Hou Ying Chen Jun Ni State Key Laboratory of Low-Dimensional Quantum Physics Department of PhysicsTsinghua UniversityBeijing100084China Frontier Science Center for Quantum Information Beijing100084China Fracture and Reliability Research Institute School of EngineeringTohoku University6-6-01 AramakiaobaAobakuSendai980-8579Japan College of Physics Science and Technology Yangzhou UniversityYangzhou225002China Collaborative Innovation Center of Quantum Matter Beijing100084China

When developing deep learning models for accurate property prediction,it is sometimes overlooked that some material physical properties are insensitive to the local atomic ***,we propose the elemental convolution neural networks(ECNet)to obtain more general and global element-wise representations to accurately model material *** shows better prediction in properties like band gaps,refractive index,and elastic moduli of *** explore its application on high-entropy alloys(HEAs),we focus on the FeNiCoCrMn/Pd systems based on the data of DFT *** knowledge from less-principal element alloys can enhance performance in HEAs by transfer learning ***,the element-wise features from the parent model as universal descriptors retain good accuracy at small data *** this framework,we obtain the concentration-dependent formation energy,magnetic moment and local displacement in some sub-ternary and quinary *** results enriched the physics of those high-entropy alloys.

关键词： alloys prediction entropy

A deep neural network-based algorithm for solving structural optimization

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2021年第8期22卷 609-620页

作者： dung nguyen KIEN Xiaoying ZHUANG Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai 200092China Institute of Photonics Department of Mathematics and PhysicsLeibniz University HannoverD-30167 HannoverGermany Hannover Center for Optical Technologies Leibniz University HannoverD-30167 HannoverGermany

We propose the deep Lagrange method(DLM),which is a new optimization method,in this *** is based on a deep neural network to solve optimization *** method takes the advantage of deep learning artificial neural networks to find the optimal values of the optimization function instead of solving optimization problems by calculating sensitivity *** DLM method is non-linear and could potentially deal with nonlinear optimization *** test cases on sizing optimization and shape optimization are performed,and their results are then compared with analytical and numerical solutions.

关键词： Structural optimization Deep learning Artificial neural networks Sensitivity analysis

Nanofibrillar collagen scaffolds for lymphedema treatment:current applications and future directions

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Plastic and Aesthetic Research 2022年第1期9卷 490-502页

作者： Pooja S.Yesantharao dung H.nguyen Division of Plastic&Reconstructive Surgery Stanford University School of MedicineStanfordCA 94304USA

Aim:Biosynthetic scaffolds represent cutting-edge therapeutic efforts for secondary *** particular,nanofibrillar collagen scaffolds have shown efficacy in both preclinical and clinical contexts,and there has been growing interest in these scaffolds in recent *** study systematically reviewed the current literature on nanofibrillar collagen scaffolds for lymphedema treatment to synthesize findings and highlight areas for further ***:This was a systematic scoping review of the literature on nanofibrillar collagen scaffolds for lymphedema ***:Upon review of the literature,32 relevant articles were identified,of which seven articles specifically investigating nanofibrillar collagen scaffolds were selected for *** these articles,three investigated scaffold placement in small or large animal models,while four were clinical investigations ranging from case reports to retrospective cohort *** all studies,scaffold implantation was associated with significant improvement in lymphedema symptoms compared to untreated controls,especially when used in combination with physiologic microsurgical procedures such as vascularized lymph node ***,even when used alone or in combination with lymph node fragments,subcutaneous placement of these scaffolds improved lymphedema ***,in a rodent model of lymphedema,scaffold placement at the time of lymph node harvest forestalled the development of lymphedema,highlighting the preventative capacity of these scaffolds as ***:Nanofibrillar collagen scaffolds have been demonstrated to effectively treat and/or prevent secondary lymphedema in both preclinical and clinical ***,these scaffolds represent a promising intersection of tissue engineering and lymphedema therapy,and further clinical investigation is warranted.

关键词： Biomaterials lymphedema biosynthetic scaffold lymphangiogenesis regenerative medicine adiposederived stem cells

Promote Combinational Researches, Training, and Applied Scientific Technology in Universities and Institutes in Vietnam

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Sociology Study 2016年第5期6卷 342-347页

作者： Thi dung nguyen Hong Phuc nguyen University of Labour and Social Affairs Hanoi city Viemam Military Medical Chamber National Defense AcademyHanoi city Vietnam

To promote the combination of research, training, and scientific technology application is the main policy of the Vietnam Communist Party and State of their management to their meeting of the needs toward their radical and comprehensive renovation with educational and training processes. There are some solutions such as： To develop a national project on combination of research and scientific technology application in social science in Vietnam was administered, to develop a set of criteria to ensure effectiveness of combination of research and training which will be based on the needs of society was assessed, to increase self-control of research institutes and universities of social science sector in combination of research and scientific technology application was examined, to be continued of the renovation management mechanism was managed, the cost norm and means of providing finance research and scientific technology application in social science were founded. The comprehensive legal framework and criteria of combination of research and scientific technology application as a basic for evaluating activities of research and scientific technology application in social science were used. Suggestions that this study was to apply scientific technology in transferring national university and investigation of the key universities into universities＇ researches were provided.

关键词： Scientific train institute university social science

Systemic-to-pulmonary artery pressure ratio as a predictor of patient outcome following liver transplantation

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World Journal of Hepatology 2016年第32期8卷 1384-1391页

作者： Annette Rebel dung nguyen Brooke Bauer Paul A Sloan Amy DiLorenzo Zaki-Udin Hassan Department of Anesthesiology and Surgery Medical Center N 202University of Kentucky

AIM To assess the value of the mean systemic-to-pulmonary artery pressure(MAP/m PAP) ratio for predicting outcomes following orthotopic liver transplant(OLT). METHODS A retrospective data analysis was performed and data(mean arterial blood pressure, mean pulmonary artery pressure and Cardiac Index) were collected at several points during OLT. Outcomes evaluated were duration of postoperative endotracheal intubation [ET; minutes after intensive care unit(ICU) arrival], length of ICU stay, total hospitalization and frequency of immediate postoperative complications. A total of 91 patients were included in the data analysis. Based on the intraoperative course of the MAP/m PAP ratio, 2 hemodynamic responses were identified: Group 1(MAP/m PAP ratio increase during anhepatic period with postreperfusion recovery, n = 66); and Group 2(MAP/m PAP ratio with no change during anhepatic period or decreased without recovery, n = 25). RESULTS The main finding was that the lack of increased MAP/m PAP ratio in the anhepatic period was associated with:(1) longer intubation times; and(2) prolonged ICU stays and total hospitalization time, when compared to patients with an increase in MAP/m PAP ratio during the anhepatic period. CONCLUSION The data from this retrospective study should raise awareness to the mean systemic to pulmonary artery pressure ratio as a potential indicator for poor outcome after OLT. Further prospective studies are needed for validation.

关键词： Anesthesiology Liver transplantation Right heart function Outcome Morbidity

Performance of the Cloud-Based Commodity Cluster

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Computer Technology and Application 2013年第10期4卷 532-537页

作者： Van-Hau Pham Duc-Cuong nguyen Tien-dung nguyen School of Computer Science and Engineering International University Hochiminh City 70000 Vietnam

Traditional HPC （High Performance Computing） cluster is built on top of physical machines. It is usually not practical to reassign these machines to other tasks due to the fact that software installation is time consuming. As a result, these machines are usually dedicated for the cluster usage. Virtualization technology provides an abstract layer which allows several different operating systems （with different software packages） running on top of one physical machine. Cloud computing provides an easy way for the user to manage and interact with the computing resources （the virtual machines in this case）. In this work, we demonstrate the feasibility of building a cloud-based cluster for HPC on top of a set of desktop computers that are interconnected by means of Fast Ethernet. Our cluster has several advantages. For instance, the deployment time of the cluster is quite fast： We need only 5 min to deploy a cluster of 30 machines, Besides, several performance benchmarks have been carried out. As expected, the embarrassingly parallel problem has the linear relationship between the performance and the cluster size.

关键词： Cloud computing HPC cluster virtualization performance.

Stress relaxation analysis of single chondrocytes using porohyperelastic model based on AFM experiments

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Theoretical & Applied Mechanics Letters 2014年第5期4卷 74-80页

作者： Trung dung nguyen Adekunle Oloyede Yuantong Gu School of Chemistry Physics and Mechanical EngineeringScience and Engineering FacultyQueensland University of Technology

Based on atomic force microscopy technique, we found that the chon- drocytes exhibits stress relaxation behavior. We explored the mechanism of this stress relaxation behavior and concluded that the intracellular fluid exuding out from the cells during deformation plays the most important role in the stress relax- ation. We applied the inverse finite element analysis technique to determine nec- essary material parameters for porohyperelastic （PHE） model to simulate stress relaxation behavior as this model is proven capable of capturing the non-linear behavior and the fluid-solid interaction during the stress relaxation of the single chondrocytes. It is observed that PHE model can precisely capture the stress re- laxation behavior of single chondrocytes and would be a suitable model for cell biomechanics.

关键词： cell biomechanics chondrocytes atomic force microscopy stress relaxation,porohyperelastic (PHE) constitutive model