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A fully automated framework for helicopter rotor blades design and analysis including aerodynamics,structure, and manufacturing

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Chinese Journal of Aeronautics 2016年第6期29卷 1602-1617页

作者： Ngoc Anh Vu Jae Woo Lee Tuan Phuong Nam Le Song Thanh thao Nguyen Division of Computational Mechatronics Institute for Computational Science Ton Duc Thang University Faculty of Electrical & Electronics Engineering Ton Duc Thang University Department of Aerospace Information Engineering Konkuk University Faculty of Mechanical Engineering Industrial University of Ho Chi Minh City Department of Aerospace Engineering Ho Chi Minh City University of Technology Vietnam National University-Ho Chi Minh City

This study describes an integrated framework in which basic aerospace engineering aspects(performance, aerodynamics, and structure) and practical aspects(configuration visualization and manufacturing) are coupled and considered in one fully automated design optimization of rotor blades. A number of codes are developed to robustly perform estimation of helicopter configuration from sizing, performance analysis, trim analysis, to rotor blades configuration representation. These codes are then integrated with a two-dimensional airfoil analysis tool to fully design rotor blades configuration including rotor planform and airfoil shape for optimal aerodynamics in both hover and forward flights. A modular structure design methodology is developed for realistic composite rotor blades with a sophisticated cross-sectional geometry. A D-spar cross-sectional structure is chosen as a baseline. The framework is able to analyze all realistic inner configurations including thicknesses of D-spar, skin, web, number and ply angles of layers of each composite part,and materials. A number of codes and commercial software(ANSYS, Gridgen, VABS, Pre VABS,etc.) are implemented to automate the structural analysis from aerodynamic data processing to sectional properties and stress analysis. An integrated model for manufacturing cost estimation ofcomposite rotor blades developed at the Aerodynamic Analysis and Design Laboratory(AADL),Aerospace Information Engineering Department, Konkuk University is integrated into the framework to provide a rapid and dynamic feedback to configuration design. The integration of three modules has constructed a framework where the size of a helicopter, aerodynamic performance analysis, structure analysis, and manufacturing cost estimation could be quickly investigated. All aspects of a rotor blade including planform, airfoil shape, and inner structure are considered in a multidisciplinary design optimization without an exception of critical configuration.

关键词： Design optimization Helicopter rotor blades Integrated framework Modular structure design methodology Perform estimation

Update on global epidemiology of viral hepatitis and preventive strategies

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World Journal of Clinical Cases 2018年第13期6卷 589-599页

作者： Meryem Jefferies Bisma Rauff Harunor Rashid thao Lam Shafquat Rafiq Drug Health Western Sydney Local Health District Westmead Institute for Medical Research Westmead Hospital Sydney Medical School University of Sydney National Centre for Immunisation Research and Surveillance of Vaccine Preventable Diseases the Children’s Hospital at Westmead and the Discipline of Child and Adolescent Health Sydney Medical School Croydon University Hospital NHS Trust

Viral hepatitis is one of the major public health concerns around the world but until recently it has drawn little attention or funding from global health *** year 1.4 million people die from viral hepatitisrelated cirrhosis and liver ***,the majority of the infected population are unaware of their *** population have significant obstacles to overcome such as lack of awareness,vulnerability,increased migration,disease stigma,discrimination,as well as poor health resources,conflict in policy development and program *** implementing infection control measures over the last few decades eradication or significant disease reduction remains *** study aims to present the current global prevalence status and examines potential elimination *** information for this research were obtained through a systematic review,published scientific literatures,the official websites of various government organisations,international public health organisations and internationally recognised regulatory bodies over a period of 40 years between 1978 and2018.

关键词： Cirrhosis Global epidemiology Outreach clinic Liver cancer Vaccination Viral hepatitis

Localized Exponential Time Differencing Method for Shallow Water Equations: Algorithms and Numerical Study

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Communications in Computational Physics 2021年第1期29卷 80-110页

作者： Xucheng Meng Thi-thao-Phuong Hoang Zhu Wang Lili Ju Department of Mathematics University of South CarolinaColumbiaSC 29208USA Department of Mathematics and Statistics Auburn UniversityAuburnAL 36849USA SUSTech International Center for Mathematics Southern University of Science and TechnologyShenzhenGuangdong 518055China Center for Mathematical studies Advanced Institute of Natural SciencesBeijing Normal University at ZhuhaiZhuhaiGuangdong 519087China

In this paper,we investigate the performance of the exponential time differencing(ETD)method applied to the rotating shallow water *** with explicit time stepping of the same order accuracy in time,the ETD algorithms could reduce the computational time in many cases by allowing the use of large time step sizes while still maintaining numerical *** accelerate the ETD simulations,we propose a localized approach that synthesizes the ETD method and overlapping domain *** dividing the original problem into many subdomain problems of smaller sizes and solving them locally,the proposed approach could speed up the calculation of matrix exponential vector *** standard test cases for shallow water equations of one or multiple layers are *** results show great potential of the localized ETD method for high-performance computing because each subdomain problem can be naturally solved in parallel at every time step.

关键词： Exponential time differencing domain decomposition rotating shallow water equa-tions finite volume discretization

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

Deep learning-based signal processing for evaluating energy dispersal in bridge structures

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2021年第8期22卷 672-680页

作者： Nhi NGO-KIEU thao NGUYEN-DA Toan PHAM-BAO Tam NGUYEN-NHAT Hung NGUYEN-XUAN Laboratory of Applied Mechanics(LAM) Ho Chi Minh City Univer-sity of Technology(HCMUT)Ho Chi Minh CityVietnam Vietnam National University Ho Chi Minh City Ho Chi Minh CityVietnam Ho Chi Minh City Department of Transportation Ho Chi Minh CityVietnam CIRTECH Institute Ho Chi Minh City University of Technology(HUTECH)Ho Chi Minh CityVietnam

In this paper,we use deep learning to investigate a loss factor function(LF)for measuring energy dispersal in bridge structures in Ho Chi Minh City,*** LF is calculated from the power spectral density(PSD)of random vi... 详细信息

关键词： bridge energy dispersal

Evaluation of deep learning algorithms for national scale landslide susceptibility mapping of Iran

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Geoscience Frontiers 2021年第2期12卷 505-519页

作者： Phuong thao Thi Ngo Mahdi Panahi Khabat Khosravi Omid Ghorbanzadeh Narges Kariminejad Artemi Cerda Saro Lee Institute of Research and Development Duy Tan UniversityDa Nang550000Viet Nam Division of Science Education Kangwon National UniversityChuncheon-siGangwon-do24341Republic of Korea Geoscience Platform Division Korea Institute of Geoscience and Mineral Resources(KIGAM)124Gwahak-ro Yuseong-guDaejeon34132Republic of Korea Department of Watershed Management Engineering Sari Agricultural Science and Natural Resources UniversitySariIran Department of Geoinformatics–Z_GIS University of SalzburgSalzburg5020Austria Department of Watershed and Arid Zone Management Gorgan University of Agricultural Sciences and Natural ResourcesGorgan49189-434Iran Soil Erosion and Desertification Research Group Department of GeographyUniversity of ValenciaValenciaSpain Department of Geophysical Exploration Korea University of Science and Technology217 Gajeong-ro Yuseong-guDaejeon34113Republic of Korea

The identification of landslide-prone areas is an essential step in landslide hazard assessment and mitigation of landslide-related *** this study,we applied two novel deep learning algorithms,the recurrent neural network(RNN)and convolutional neural network(CNN),for national-scale landslide susceptibility mapping of *** prepared a dataset comprising 4069 historical landslide locations and 11 conditioning factors(altitude,slope degree,profile curvature,distance to river,aspect,plan curvature,distance to road,distance to fault,rainfall,geology and land-sue)to construct a geospatial database and divided the data into the training and the testing *** then developed RNN and CNN algorithms to generate landslide susceptibility maps of Iran using the training *** calculated the receiver operating characteristic(ROC)curve and used the area under the curve(AUC)for the quantitative evaluation of the landslide susceptibility maps using the testing *** performance in both the training and testing phases was provided by the RNN algorithm(AUC=0.88)than by the CNN algorithm(AUC=0.85).Finally,we calculated areas of susceptibility for each province and found that 6%and 14%of the land area of Iran is very highly and highly susceptible to future landslide events,respectively,with the highest susceptibility in Chaharmahal and Bakhtiari Province(33.8%).About 31%of cities of Iran are located in areas with high and very high landslide *** results of the present study will be useful for the development of landslide hazard mitigation strategies.

关键词： CNN RNN Deep learning Landslide Iran

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

Some problems on the research and development of the application of methane draining boring technology to prevent hazards in underground coal mines in Vietnam

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Journal of Coal Science & Engineering(China) 2009年第2期15卷 129-133页

作者： NGUYEN Xuan-thao NGUYEN Tran-Tuan TRAN Dinh-Kien Institute of Mining Science and Technology University of Mining and Geology

Underground coal mining activities in the Quangninh coal basin (in the North ofVietnam) have been carried out at a depth of-130 m to-150 m,and in the near future thismining depth will become-300 m and-500 *** with the increasing coal output,the quantity of methane and other mine gases emitted from coal beds during mining activitieswill grow bigger and *** to the forecast of the coal mining industry,ifmines go deeper downward,all underground coal mines in the Quangninh basin will beclassified into the mine group with the dangerous level of methane *** gascontrol and management operations with conventional ventilation are less effective andentail high *** of the main solutions is to carry out short,medium and longboreholes for controlling and recovering methane and other mine gases from coal bedsbefore mining *** of drilling activities for methane gas recovery from coalseams with horizontal bore holes at underground coal mines depends on many factors includingthe mine gas draining borehole layout at the roadways,gas content in the coalbeds,technologies for mine gas draining boring activities,and so *** gas existsin the coal beds under the adhesive state with stable physical and chemical *** orderto recover these gases,it is necessary to carry out boreholes and create artificial joints(collecting pits) in coal beds with the impulse method (hydraulic separation method).

关键词：地下煤矿甲烷排放钻孔技术越南危险煤层开采应用开发

Porphyromonas gingivalis Resistance to Polymyxin B Is Determined by the Lipid A 4’-Phosphatase, PGN_0524

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International Journal of Oral Science 2009年第3期1卷 126-135页

作者： Stephen R. Coats thao T. To Sumita Jain Pamela H. Braham Richard P. Darveau Department of Periodontics School of Dentistry University of Washington Seattle USA

Aim To elucidate the genetic basis for the pronounced resistance that the oral pathogen, Porphyromonas gingivalis （P. gingivalis）, exhibits towards the cationic antimicrobial peptide, polymyxin B. Methodology A genetic screen of P. gingivalis clones generated by a Tn4400-based random insertion mutagenesis strategy was performed to identify bacteria harboring novel genetic mutations that render P. gingivalis susceptible to killing by the cationic antimicrobial peptide, polymyxin B （PMB, 50μg·mL^-1）. Results P. gingivalis （ATCC 33277） is unusually resistant to the cationic antimicrobial peptide, PMB at relatively high concentrations （200μg·mL^-1）. Approximately 2,700 independent Tn4400 ＇-derived mutants ofP. gingivalis were examined for increased sensitivity to PMB killing at a relatively low dose （50 μg·mL^-1）. A single PMB-sensitive mutant was obtained in this phenotypic screen. We determined that the Tn4400＇ transposon was integrated into the gene encoding the lipid A 4＇-phosphatase, PGN 0524, demonstrating that this insertion event was responsible for its increased susceptibility of this clone to PMB-dependent killing. The resulting mutant strain, designated 0524-Tn4400＇, was highly sensitive to PMB killing relative to wild-type P. gingivalis, and exhibited the same sensitivity as the previously characterized strain, 0524KO, which bears a genetically engineered deletion in the PGN_0524 locus. Positive ion mass spectrometric structural （MALDI-TOF MS） analyses revealed that lipid A isolates from 0524-Tn4400＂ and 0524KO strains displayed strikingly similar MALDI-TOF MS spectra that were substantially different from the wildtype P gingivalis lipid A spectrum. Finally, intact 0524- Tn4400＇ and 0524KO mutant bacteria, as well as their corresponding LPS isolates, were significantly more potent in stimulating Toll-like receptor 4 （TLR4）-dependent E-selectin expression in human endothelial cells relative to intact wild-type P.. gingivalis or its corresponding LPS isolate.

关键词： P. gingivalis antimicrobial peptide lipid A phosphatase polymyxin B transposon lipopolysaccharide