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Numerical investigation of aerodynamic flow actuation produced by surface plasma actuator on 2D oscillating airfoil

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Chinese Journal of Aeronautics 2016年第4期29卷 882-892页

作者： Minh Khang phan Jichul Shin Department of Aerospace Engineering University of Ulsan

Numerical simulation of unsteady flow control over an oscillating NACA0012 airfoil is investigated. Flow actuation of a turbulent flow over the airfoil is provided by low current DC surface glow discharge plasma actuator which is analytically modeled as an ion pressure force produced in the cathode sheath region. The modeled plasma actuator has an induced pressure force of about 2 k Pa under a typical experiment condition and is placed on the airfoil surface at 0% chord length and/or at 10% chord length. The plasma actuator at deep-stall angles(from 5° to 25°) is able to slightly delay a dynamic stall and to weaken a pressure fluctuation in down-stroke motion. As a result, the wake region is reduced. The actuation effect varies with different plasma pulse frequencies, actuator locations and reduced frequencies. A lift coefficient can increase up to 70% by a selective operation of the plasma actuator with various plasma frequencies and locations as the angle of attack changes. Active flow control which is a key advantageous feature of the plasma actuator reveals that a dynamic stall phenomenon can be controlled by the surface plasma actuator with less power consumption if a careful control scheme of the plasma actuator is employed with the optimized plasma pulse frequency and actuator location corresponding to a dynamic change in reduced frequency.

关键词： Dynamic stall Flow control Numerical simulation Oscillating airfoil Plasma actuator

Poroelastodynamic responses and elastic moduli of a transversely isotropic porous cylinder under forced deformation test

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International Journal of Mining Science and Technology 2023年第7期33卷 793-800页

作者： Chao Liu Dung T.phan Aramco Research Center-Houston Houston TX 77084USA

Existing transversely isotropic poroelastodynamics solutions are limited to infinite domains and without experimental validation. Furthermore, there is a lack of analytical simulations for the elastic moduli dispersion of fluid-saturated porous cylinders. To address these three limitations and investigate the mechanisms of moduli dispersion, we present the analytical solutions of the poromechanical responses and the elastic moduli dispersion of a transversely isotropic, fluid-saturated, finite porous cylinder subjected to a forced deformation test. Through an example, we demonstrate the effects of loading frequency, boundary conditions, and material's anisotropy, dimension, and permeability on the responses of pore pressure,force, displacement, and dynamic elastic moduli of the cylinder. The specimen's responses are significantly influenced by the frequency of the applied load, resulting in a drained state at low frequencies and an undrained state at high frequencies. At high frequencies, the sample behaves identically for an open or a closed lateral boundary, and permeability has insignificant effects. The dynamic elastic moduli are mainly controlled by the loading frequency and the ratio of the sample's radius to its height. Lastly,we show excellent matches between the newly derived analytical solution and laboratory measurements on one clay and two shale samples from Mont Terri.

关键词： Poroelastodynamics Dynamic moduli Transversely isotropic Porous cylinder Forced deformation test

Stochastic Programming For Order Allocation And Production Planning

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Computer Systems Science & Engineering 2022年第1期40卷 75-85页

作者： phan Nguyen Ky Phuc International University-Vietnam National University Vietnam National UniversityHoChiMinh City70000Vietnam

Stochastic demand is an important factor that heavily affects production *** influences activities such as purchasing,manufacturing,and selling,and quick adaption is *** production planning,for reasons such as reducing costs and obtaining supplier discounts,many decisions must be made in the initial stage when demand has not been *** effects of non-optimal decisions will propagate to later stages,which can lead to losses due to overstocks or *** find the optimal solutions for the initial and later stage regarding demand realization,this study proposes a stochastic two-stage linear program-ming model for a multi-supplier,multi-material,and multi-product purchasing and production planning *** objective function is the expected total cost after two stages,and the results include detailed plans for purchasing and production in each demand ***-scale problems are solved through a deterministic equivalent transformation *** solve the problems in the large scale,an algorithm combining metaheuristic and sample average approximation is *** algorithm can be implemented in parallel to utilize the power of the *** algorithm based on the observation that if the remaining quantity of materials and number of units of products at the end of the initial stage are given,then the problems of the first and second stages can be decomposed.

关键词： Mixed integer programming two-stage stochastic programming production planning order allocation

Generation of Control Moments in an Insect-like Tailless Flapping-wing Micro Air Vehicle by Changing the Stroke-plane Angle

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Journal of Bionic Engineering 2016年第3期13卷 449-457页

作者： Hoang Vu phan Hoon Cheol Park Artificial Muscle Research Center Konkuk University Seoul 143-701 South Korea Deptment of Advanced Technology Fusion Konkuk University Seoul 143-701 South Korea

We propose a control moment generator to control the attitude of an insect-like tailless Flapping-wing Micro Air Vehicle （FW-MAV）, where the flapping wings simultaneously produce the flight force and control moments. The generator tilts the stroke plane of each wing independently to direct the resultant aerodynamic force in the desired direction to ultimately generate pitch and yaw moments. A roll moment is produced by an additional mechanism that shifts the trailing edge, which changes the wing rotation angles of the two flapping wings and produces an asymmetric thrust. Images of the flapping wings are captured with a high-speed camera and clearly show that the FW-MAV can independently change the stroke planes of its two wings. The measured force and moment data prove that the control moment generator produces reasonable pitch and yaw moments by tilting the stroke plane and realizes a roll moment by shifting the position of the trailing edge at the wing root.

关键词： insect-like Flapping-wing Micro Air Vehicle (FW-MAV) control mechanism stroke plane beetle flight

Epidemiology and Clonal Spread Evidence of Carbapenem-Resistant Organisms in the Center of Care and Protection of Orphaned Children, Vietnam

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Open Journal of Medical Microbiology 2024年第3期14卷 165-189页

作者： Van Kim Nguyen Pirom Noisumdaeng Pol. Maj. Katiya Ivanovitch Stephen Baker Eugene Athan Stephanie Jones Le Thi Lan Larry Croft Yin Peng Lee Tara Cassidy Van Hung Tran Thi Hang phan Huu Tinh Ho Faculty of Public Health Thammasat University Bangkok Thailand Department of Prevention and Infection Control Hung Vuong Hospital HCM City Vietnam Microbiology of Faculty of Public Health Thammasat University Bangkok Thailand Thammasat University Research Unit in Modern Microbiology and Public Health Genomics Thammasat University Bangkok Thailand National Heart & Lung Institute (NHLI) University of Cambridge Cambridge UK Barwon South West Public Health Unit Geelong Australia Center for Innovation in Infectious Disease and Immunology Research (CIIDIR) Geelong Australia School of Medicine Deakin University Burwood Australia Monash Health Berwick Australia Center of Care and Protection of Orphaned Children HCM City Vietnam Charles River Laboratories Microbial Solutions Melbourne Australia Personnel Department of Nhan Dan Gia Dinh Hospital HCM City Vietnam Hung Vuong Hospital HCM City Vietnam Department of Epidemiology Institute of Public Health HCM City Vietnam

Objective: To determine the prevalence of colonization and transmission of carbapenem-resistant Gram-negative organisms in order to develop of an effective infection prevention program. Design: Cross-sectional study with carbapenem-resistant organisms (CRO) colonization detection from the fecal specimens of 20 Health Care Workers (HCWs) and 67 residents and 175 random environment specimens from September 2022 to September 2023. Setting: A Care and Protection Centre of Orphaned Children in South of HCM City. Participants: It included 20 HCWs, 67 residents, and 175 randomly collected environmental specimens. Method: Rectal and environmental swabs were collected from 20 HCWs, 67 residents (most of them were children), and 175 environmental specimens. MELAB Chromogenic CARBA agar plates, Card NID, and NMIC-500 CPO of the BD Phoenix TM Automated Microbiology System and whole genome sequencing (WGS) were the tests to screen, confirm CROs, respectively and determine CRO colonization and transmission between HCWs, residents, and the environment. Result: We detected 36 CRO isolates, including 6, 11 and 19 CROs found in 6 HCWs, 10 residents and 19 environments. The prevalence of detectable CRO was 30% (6/20) in HCWs, 14.92% (10/67) in residents, and 10.86% (19/175) in environmental swabs in our study. WGS demonstrated CRO colonization and transmission with the clonal spread of E. coli and A. nosocomialis, among HCWs and residents (children). Conclusion: Significant CRO colonization and transmission was evident in HCWs, residents, and the center environment. Cleaning and disinfection of the environment and performing regular hand hygiene are priorities to reduce the risk of CRO colonization and transmission.

关键词： Carbapenem-Resistant Organisms Contamination Hand Hygiene Whole Genome Sequencing Infection Prevention

Cellular nanovesicles for therapeutic immunomodulation:A perspective on engineering strategies and new advances

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Acta Pharmaceutica Sinica B 2023年第5期13卷 1789-1827页

作者： Endong Zhang Philana phan Zongmin Zhao Department of Pharmaceutical Sciences College of PharmacyUniversity of Illinois ChicagoChicagoIL 60612USA Translational Oncology Program University of Illinois Cancer CenterChicagoIL 60612USA

Cellular nanovesicles which are referred to as cell-derived,nanosized lipid bilayer structures,have emerged as a promising platform for regulating immune *** to their outstanding advantages such as high biocompatibility,prominent structural stability,and high loading capacity,cellular nanovesicles are suitable for delivering various immunomodulatory molecules,such as small molecules,nucleic acids,peptides,and *** induced by cellular nanovesicles has been exploited to modulate immune cell behaviors,which is considered as a novel cell-free immunotherapeutic strategy for the prevention and treatment of diverse *** we review emerging concepts and new advances in leveraging cellular nanovesicles to activate or suppress immune responses,with the aim to explicate their applications for *** overview the general considerations and principles for the design of engineered cellular nanovesicles with tailored immunomodulatory *** also discuss new advances in engineering cellular nanovesicles as immunotherapies for treating major diseases.

关键词： Immunomodulation Cellular nanovesicle Extracellular vesicle Exosome Infectious disease Autoimmune disease Immunotherapy Immune cell

Designing Software to Analyze Sewing Process of Industrial Knitted Products

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Computer Systems Science & Engineering 2023年第2期44卷 1837-1852页

作者： phan thanh Thao Nguyen thanh Hung Pham Thi Le My Nguyen Xuan Hiep Duy-Nam phan Hanoi University of Science and Technology Hanoi10000Vietnam

In the textile industry,garment manufacturing contains four major pro-cesses containing cutting,sewing,ﬁnishing,and *** is the most crucial and intricate section,dealing with a large number of varied operations.A successful sewing process needs to be optimized regarding different factors,including time,sewing equipment,and skilled *** lineﬂow is combined by a set of operations with a particular *** utmost impor-tance of all garment industry is to arrange the workstations to minimize the num-ber of employees in order to produce at the best productive rate with the most reasonable cost,shortest time,and satisfying *** most garment factories,the production lines are balanced using the empirical judgment of the line *** the whole process the data of production time at each step,labor pro-ductivity,proper choices of equipment were always needed to calculate line efﬁ*** far as the issue is concerned,there has not been an academically sewing process analyzing software providing adequate data of sewing motions and sewing time as the credible input for the line balancing *** this goal,this paper presents the results of research on optimizing academically self-built software to analyze the sewing process of knitted products applied to industrial production using Java programming language on Google *** results achieved by the software are not only to analyze sewing products and the technological sewing process,calculate the sewing time on the machine but also analyze the sewing activities of workers into manipulations,movements,and motions to calculate the preparation time for two typical knitted products,namely,Polo-Shirt and T-Shirt with the case studies at General Textile Garment Joint Stock Company Hanoi and Star Fashion Company Limited.

关键词： Sewing motion sewing time GSD MTM polo-shirt T-shirt sewing process sewing operation analyzing software

AN EXTENSION OF ZOLOTAREV'S PROBLEM AND SOME RELATED RESULTS

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Acta Mathematica Scientia 2021年第5期41卷 1619-1634页

作者： Tran Loc HUNG phan Tri KIEN University of Finance and Marketing 77 Nguyen Kiem StreetPhu Nhuan DistrictHo Chi Minh CityVietnam

The main purpose of this paper is to extend the Zolotarev's problem concerning with geometric random sums to negative binomial random sums of independent identically distributed random *** extension is equivalent to describing all negative binomial infinitely divisible random variables and related *** Trotter-operator technique together with Zolotarev-distance's ideality,some upper bounds of convergence rates of normalized negative binomial random sums(in the sense of convergence in distribution)to Gamma,generalized Laplace and generalized Linnik random variables are *** obtained results are extension and generalization of several known results related to geometric random sums.

关键词： Zolotarev's problem geometric random sum negative binomial random sum negative binomial infinitely divisibility Trotter-operator technique

A deep learning framework to emulate density functional theory

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npj Computational Materials 2023年第1期9卷 687-695页

作者： Beatriz G.del Rio Brandon phan Rampi Ramprasad Departamento de Física Teórica Atómica yÓpticaUniversidad de ValladolidPaseo de Belén 747011 ValladolidSpain School of Materials Science and Engineering Georgia Institute of Technology771 Ferst Drive NWAtlantaGA 30332USA

Density functional theory(DFT)has been a critical component of computational materials research and discovery for ***,the computational cost of solving the central Kohn–Sham equation remains a major obstacle for dynamical studies of complex phenomena ***,we propose an end-to-end machine learning(ML)model that emulates the essence of DFT by mapping the atomic structure of the system to its electronic charge density,followed by the prediction of other properties such as density of states,potential energy,atomic forces,and stress tensor,by using the atomic structure and charge density as *** deep learning model successfully bypasses the explicit solution of the Kohn-Sham equation with orders of magnitude speedup(linear scaling with system size with a small prefactor),while maintaining chemical *** demonstrate the capability of this ML-DFT concept for an extensive database of organic molecules,polymer chains,and polymer crystals.

关键词： functional theory system