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Moving Least Squares Interpolation Based A-Posteriori Error Technique in Finite Element Elastic Analysis

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Computer Modeling in Engineering & Sciences 2021年第10期129卷 167-189页

作者： Mohd Ahmed Devender Singh Saeed Al Qadhi nguyen viet Thanh Civil Engineering Department College of EngineeringKing Khalid UniversityAbha61421Saudi Arabia Ministry of Information Soochna BhavanCGO ComplexDelhi110003India Urban Transport&Coastal Engineering Department University of Transport and CommunicationsHanoi100000Vietnam

The performance of a-posteriori error methodology based on moving least squares(MLS)interpolation is explored in this paper by varying the finite element error recovery parameters,namely recovery points and field variable derivatives *** MLS interpolation based recovery technique uses the weighted least squares method on top of the finite element method’s field variable derivatives solution to build a continuous field variable derivatives *** boundary of the node support(mesh free patch of influenced nodes within a determined distance)is taken as circular,i.e.,circular support domain constructed using radial weights is *** field variable derivatives(stress and strains)are recovered at two kinds of points in the support domain,i.e.,Gauss points(super-convergent stress locations)and nodal *** errors are computed as the difference between the stress from the finite element results and projected stress from the post-processed energy norm at both elemental and global *** benchmark numerical tests using quadrilateral and triangular meshes measure the finite element errors in strain and stress *** numerical examples showed the support domain-based recovery technique’s capabilities for effective and efficient error estimation in the finite element analysis of elastic *** MLS interpolation based recovery technique performs better for stress extraction at Gauss points with the quadrilateral discretization of the problem *** is also shown that the behavior of the MLS interpolation based a-posteriori error technique in stress extraction is comparable to classical Zienkiewicz-Zhu(ZZ)a-posteriori error technique.

关键词： Recovery points field variable derivatives effectivity error recovery support domain error convergence

The Continuous Knapsack Problem with Capacities

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Journal of the Operations Research Society of China 2021年第3期9卷 713-721页

作者： Huynh Duc quoc nguyen Chi Tam Tran Hoai Ngoc Nhan Department of Mathematics College of Natural ScienceCan Tho UniversityCan Tho City 900900Vietnam Faculty of Basic Sciences Vinh Long University of Technology EducationVinh Long 940000Vietnam

We address a variant of the continuous knapsack problem,where capacities regarding costs of items are given into *** prove that the problem is NP-complete although the classical continuous knapsack problem is solvable in linear *** the case that there exists exactly one capacity for all items,we solve the corresponding problem in O(n log n)time,where n is the number of items.

关键词： Knapsack problem Complexity Capacity Polynomially solvabl

A systematic rheological study of alkyl amine surfactants for fluid mobility control in hydrocarbon reservoirs

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Petroleum Science 2018年第3期15卷 538-551页

作者： Madalyn M. Liebum George Hirasaki quoc P. nguyen Petroleum and Geosystems Engineering Department The University of Texas at Austin 200 E.Dean Keeton St.Stop C0300 Room CPE 5.104 A Austin TX 78712 USA Highlands Ranch CO 80129 USA

The basis of this study is to identify the versatility of N,N,N＇-trimethyl-N＇-tallow-1,3-diaminopropane（DTTM） surfactant in high saline environments. The surfactant was examined with sodium chloride, NaCl, to understand how triggers such as salt, p H, temperature, and surfactant concentration influences the viscoelastic response of the surfactant solution. The DTTM surfactant and salt（NaCl） concentrations used in steady-state shear viscosity analysis range from 0.2 wt% to 2 wt%and 5 wt% to 25 wt%, respectively. Along with DTTM results, three similar chemical structures are investigated to understand how viscosity changes with alterations in tail and head group composition. It was found that DTTM surfactant has the capability of transitioning from a foam-bearing to viscoelastic state at low surfactant concentrations under moderate to high saline conditions. A longer tail length promotes viscoelasticity and shear-thinning behavior. Terminals consisting of hydroxides or ethoxylates have a lower viscosity than that of methyl terminals. A head group consisting of two nitrogen atoms has a higher viscosity than those containing one nitrogen atom. The rheological characterization of DTTM presented in this paper is part of a larger study in determining the capability of this surfactant to foam CO2 for improving mobility control in CO2 enhanced oil recovery in high saline oil formations.

关键词： Rheology Surfactants Wormlike micelles Viscoelastic Amines

20-Hydroxyecdysone from Dacrycarpus imbricatus bark inhibits the proliferation of acute myeloid leukemia cells

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Asian Pacific Journal of Tropical Medicine 2017年第2期10卷 151-153页

作者： Trinh Thi Thuy nguyen Thanh Tam nguyen Thi Hoang Anh Dang viet Hau Dinh Thi Phong Le quoc Thang Sabrina Adorisio Tran Van Sung Domenico V Delfino Institute of Chemistry Vietnam Academy of Science and Technology vietnam National Museum of Nature Vietnam Academy of Science and Technology Hue University’s College of Educations Section of Pharmacology Department of MedicineUniversity of Perugia

Objective:To investigate the anti-proliferative effects of 20-hydroxyecdysone isolated from the bark of Dacrycarpus imbricatus(Blume) de ***:Column chromatography was used for isolation of compounds from plant *** structure of the isolated compound was identified by mass spectrometry and nuclear magnetic resonance techniques,including HSQC,HMBC,NOE-difference *** isolated compound was tested for its anti-proliferative activity in acute myeloid leukemia(AML) and OCI-AML ***:Compound 1 was isolated from the ethyl acetate fraction of Dacrycarpus imbricatus barks by column *** chemical structure was identified as 20-hydroxyecdysone(20HE),a cholestane-type ecdysteroid,by a combination of mass spectrometry and nuclear magnetic resonance spectrometric *** goal was to test the anti-proliferative activity of 20 HE using the OCI-AML cell line.20 HE significantly decreased OCI cell number at a concentration of 1 mg/mL,whereas lower concentrations were ***,this decrease was due to partial blockage of the G_1/S phase of the cell cycle,with a reduction of cells in the G_2M phase,not due to increased ***:This indicates that 20 HE significantly decreases the number of cells in the G_1/S phase of the cell cycle in human AML *** is the first time that the anti-proliferative activity of 20 HE against a human tumor cell line has been reported.

关键词： Dacrycarpus imbricatus Ecdysteroid 20-hydroxyecdysone Proliferation Acute myeloid leukemia

Development of a PARCS/Serpent model for neutronics analysis of the Dalat nuclear research reactor

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Nuclear Science and Techniques 2021年第2期32卷 32-44页

作者： viet-Phu Tran Kien-Cuong nguyen Donny Hartanto Hoai-Nam Tran Vinh Thanh Tran Van-Khanh Hoang Pham Nhu viet Ha Institute for Nuclear Science and Technology(INST) Vietnam Atomic Energy Institute(VINATOM)179 Hoang Quoc Viet str.Cau Giay DistrictHanoi 100000Vietnam Nuclear Research Institute(NRI) Vietnam Atomic Energy Institute(VINATOM)01 Nguyen Tu LucDalatLamdong 670000Vietnam Department of Mechanical and Nuclear Engineering University of SharjahPO.BOX 27272SharjahUnited Arab Emirates Institute of Fundamental and Applied Sciences Duy Tan UniversityHo Chi Minh city 700000Vietnam Faculty of Natural Science Duy Tan UniversityDanang 550000Vietnam Nuclear Safety Division Technical Support Center for Radiation and Nuclear Safety and Emergency ResponseVietnam Agency for Radiation and Nuclear Safety(VARANS)113 Tran Duy Hung str.Cau Giay DistrictHanoi 100000Vietnam

Cross-sectional homogenization for full-core calculations of small and complex reactor configurations,such as research reactors,has been recently recognized as an interesting and challenging *** paper presents the development of a PARCS/Serpent model for the neutronics analysis of a research reactor type TRIGA Mark-II loaded with Russian VVR-M2 fuel(known as the Dalat Nuclear Research Reactor or DNRR).The full-scale DNRR model and a supercell model for a shim/safety rod and its surrounding fuel bundles with the Monte Carlo code Serpent 2 were proposed to generate homogenized fewgroup cross sections for full-core diffusion calculations with *** full-scale DNRR model with Serpent 2 was also utilized as a reference to verify the PARCS/Serpent *** of the effective neutron multiplication factors,radial and axial core power distributions,and control rod worths showed a generally good agreement between PARCS and Serpent *** addition,the discrepancies between the PARCS and Serpent 2 results are also ***,the results indicate the applicability of the PARCS/Serpent model for further steady state and transient analyses of the DNRR.

关键词： PARCS Serpent 2 Group constant DNRR

Minimizing Warpage for Macro-Size Fused Deposition Modeling Parts

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Computers, Materials & Continua 2021年第9期68卷 2913-2923页

作者： Thanh Thuong Huynh Tien V.T.nguyen quoc Manh nguyen Trieu Khoa nguyen Department of Mechanical Engineering Can Tho UniversityCampus IICan ThoVietnam Faculty of Mechanical Technology Industrial University of Ho Chi Minh CityHo Chi Minh70000Vietnam Mechanical Engineering Department National Kaohsiung University of Science and TechnologyKaohsiung80778Taiwan Faculty of Mechanical Engineering Hung Yen University of Technology and EducationHung Yen16000Vietnam

In this study,we investigated warpage and corner lifting minimization for three-dimensional printed parts generated by macro-size fused deposition modeling(FDM).First,the reasons for warpage were theoretically *** approach revealed that the thermal deformation and differential volumetric shrinkage of the extruded molten plastic resulted in warpage of FDM *** addition,low adhesion between the deposited model and the heated or non-heated printing bed may intensify warpage *** a next step,initial small-size and medium-size models were used to identify parameters to manage and minimize warpage in a way that would reduce material consumption and running ***,a macro-size model was built to experimentally investigate and verify the technical solutions to minimize the warpage of FDM *** conclusion,an improved part with reduced warpage was efficiently produced after detailed consideration of thermal effects and adhesion *** exists to widen the application scope of FDM technology in manufacturing for processes like thermoforming that involve mold core fabrication with *** technology,which has applications not only in mechanical engineering but also in related engineering fields,is convenient and could readily be applied to practical manufacturing industries.

关键词： Fused deposition modeling corner lifting volumetric shrinkage thermal deformation acrylonitrile butadiene styrene filament

Simultaneous Quantitative Analysis of Five Components in Angelica sinensis and Angelica acutiloba Acclimatized Growing in vietnam by High-Performance Liquid Chromatography with Photodiode Array Detector

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World Journal of Traditional Chinese Medicine 2021年第1期7卷 6-10页

作者： Thi Minh Tam Pham Thi Thu Cuc Le Van Thanh nguyen viet hung Tran Departments of Microbiology Institute of Drug Quality ControlHo Chi Minh City Departments of Instrumental Analysis Institute of Drug Quality ControlHo Chi Minh City Institute of Drug Quality Control Ho Chi Minh City Faculty of Pharmacy Nguyen Tat Thanh UniversityHo Chi Minh CityVietnam

Background:Chinese Danggui(Angelica sinensis)and Japanese Danggui(Angelica acutiloba)are evaluated as the same in using and critical of quality control in vietnamese *** vietnam,Japanese Danggui were acclimatized and cultivated in several regions in recent *** the huge climatic difference between vietnam and Japan,Japanese Danggui grows very well in ***,there are no studies to assess the overall quality of this medicinal *** and Objectives:The aim of this study is to develop a method to identify and assay simultaneously 5 component compounds of these crude herbs:chlorogenic acid,ferulic acid,scopoletin,xanthotoxin and ligustilide by high-performance liquid chromatography with photodiode array detector(HPLC-PDA).Materials and Methods:The procedure was optimized by using column Phenomenex Gemini 5μm PR C18,15 x 4,6 mm with the detection wavelength set at 321 nm for detector PDA and mobile phase was composed of(A)ACN and(B)aqueous solution 1%of acid acetic using a gradient *** were performed at 30°C with a flow rate of 1.0 mL/***:The developped method were fully validated for linearity,accuracy,recovery and met the validation requirements,proved practical applicability for the quality control of these herbs and related ***:The method was successfully applied to the quantification of five markers simultaneously from collected samples.

关键词： Chlorogenic acid Danggui ferulic acid ligustilide scopoletin xanthotoxin

Effectiveness of bee venom acupuncture for patients suffering from periarthritis humeroscapularis

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中医杂志:英文版 2023年第4期43卷 795-800页

作者： Minh Duc nguyen Thanh Van Tran quoc Vinh nguyen Cay Doan Ha Linh Vu Phuong Dang Senior Specialist Clinic National Hospital of AcupunctureHanoi 1000Vietnam Department of Senior Specialist National Hospital of Acupuncture Hanoi 1000Vietnam Department of Senior Specialist Military Institute of Traditional MedicineHanoi 1000Vietnam Department of minimally invasive spine National Hospital of AcupunctureHanoi 1000Vietnam Department of Medicine Dai Nam UniversityHanoi 1000Vietnam

OBJECTIVE:To evaluate the efficacy of bee venom acupuncture in humeroscapularis(PHS)***:One hundred and twenty patients diagnosed with PHS were assigned into four groups:BV1(0.01 mg/kg),BV2(0.005 mg/kg),BV3(0.0025 mg/kg),and control group(vitamin B1 plus novocain 3%injection)with 15 d of *** outcomes of the study including visual analogue scale(VAS)score andβ-endorphin,inflammatory cytokines including interleukin-10(IL-10),IL-1βand tumor necrosis factorα(TNF-α)and shoulder function score were assessed at baseline,after 10 and 15 d of ***:All four groups reported statistically significant improvement in VAS score,motion range,and shoulder function score(Pvietnam and other groups.

关键词： periarthritis humeroscapularis bee venom acupuncture visual analogue scale range of motion articular shoulder function score inflammatory cytokines

Prediction of BRIC Stock Price Using ARIMA,SutteARIMA,and Holt-Winters

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Computers, Materials & Continua 2022年第1期70卷 523-534页

作者： Ansari Saleh Ahmar Pawan Kumar Singh nguyen Van Thanh nguyen viet Tinh Vo Minh Hieu Department of Statistics Faculty of Mathematics and Natural ScienccesUniversitas Negeri MakassarMakassar90223Indonesia School of Humanities and Social Sciences Thapar Institute of Engineering and TechnologyPatiala147004India Faculty of Commerce Van Lang UniversityHo Chi Minh City70000Vietnam

The novel coronavirus has played a disastrous role in many countries *** outbreak became a major epidemic,engulfing the entire world in lockdown and it is now speculated that its economic impact might be worse than economic deceleration and *** paper identifies two different models to capture the trend of closing stock prices in Brazil(BVSP),Russia(***),India(BSESN),and China(SSE),i.e.,(BRIC)*** predict the stock prices for three daily time periods,so appropriate preparations can be undertaken to solve these ***,we compared the ARIMA,SutteARIMA and Holt-Winters(H-W)methods to determine the most effective model for predicting *** stock closing price of BRIC country data was obtained from Yahoo *** data dates from 01 November 2019 to 11 December 2020,then divided into two categories-training data and test *** data covers 01 November 2019 to 02 December *** days(03December 2020 to 11December 2020)of datawas tested to determine the accuracy of the models using training data as a *** measure the accuracy of the models,we obtained the means absolute percentage error(MAPE)and mean square error(MSE).Prediction model Holt-Winters was found to be the most suitable for forecasting the Brazil stock price(BVSP)while MAPE(0.50)and MSE(579272.65)with Holt-Winters(smaller than ARIMA and SutteARIMA),model SutteARIMA was found most appropriate to predict the stock prices of Russia(***),India(BSESN),and China(SSE)when compared to ARIMA and *** andMSE with SutteARIMA:Russia(MAPE:0.7;MSE:940.20),India(MAPE:0.90;MSE:207271.16),and China(MAPE:0.72;MSE:786.28).Finally,Holt-Winters predicted the daily forecast values for the Brazil stock price(BVSP)(12 December to 14 December 2020 i.e.,115757.6,116150.9 and 116544.1),while SutteARIMA predicted the daily forecast values of Russia stock prices(***)(12 December to 14 December 2020 i.e.,3238.06,3241.54 and 3245.01),India stock price(BSESN)(

关键词： SutteARIMA Holt-Winters ARIMA stock price COVID-19