LOWER EXTREMITY INJURY OF VIETNAMESE PEDESTRIAN IN CRASH BY A SEDAN USING NUMERICAL SIMULATION

Phu Thuong Luu Nguyen,Hung Anh Ly,Thien Phu Nguyen 한국자동차공학회 2023 International journal of automotive technology Vol.24 No.1

Pedestrians are among the most vulnerable road users, who often suffer serious injuries in road collisions. Therefore, evaluating the injury of a pedestrian is absolutely necessary. This paper aims to evaluate the lower extremity injuries for Vietnamese people by numerical simulation using a Human Body Model (HBM) – Total Human Model for Safety (THUMS). Considering that the HBM has the anthropometrical and biomechanical properties of the North American and European bodies, it is required to scale it down to represent Vietnamese anthropometry. Furthermore, it is necessary to develop a scaling algorithm to scale the published lower extremity injury criteria to properly assess the injury risk of a Vietnamese. After a Vietnamese-sized HBM is obtained from the scaling procedure, its posture is adjusted to represent a walking pedestrian. A sedan is employed for simulating the pedestrian collision with the impact velocity ranging from 20 to 50 km/h. The car models are simplified to reduce computational time. The findings illustrate that the bending moment and resultant force of femur and tibia increase with respect to the impact velocity. The knee ligaments have been injured at high risk.

Red-emitting α-SrO·3B2O3:Sm2+ Phosphor for WLED Lamps: Novel Lighting Properties with Two-layer Remote Phosphor Package

Phu Tran Tin,Nhan K. H. Nguyen,Minh Q. H. Tran,Hsiao-Yi Lee 한국광학회 2017 Current Optics and Photonics Vol.1 No.4

This paper investigates a method to improve the lighting performance of white light-emitting diodes(WLEDs), which are packaged using two separate remote phosphor layers, a yellow-emitting YAG:Cephosphor layer and a red-emitting α-SrO·3B2O3:Sm2+ phosphor layer. The thicknesses of these two layersare 800 μm and 200 μm, respectively. Both of them are examined in conditions where the averagecorrelated color temperatures (CCT) are 7700 K and 8500 K. For this two-layer model, the concentrationof red phosphor is varied from 2% to 30% in the upper layer, while in the lower layer the yellow phosphorconcentration is kept at 15%. It was found interestingly that the lighting properties such as color renderingindex (CRI) and luminous flux are enhanced significantly, while the color uniformity is maintained ina relatively close range to the one of one-layer configuration (measured at the same correlated colortemperature). Besides, the transmitted and reflected light of each phosphor layer are revised by combiningKubelka-Munk and Mie-Lorenz theories. Through analysis, it is demonstrated that the packagingconfiguration of two-layer remote phosphor that employs red-emitting α-SrO·3B2O3:Sm2+ phosphor particlesprovides a practical solution for general WLEDs lighting.

Enzymatic synthesis of pure maltodextrins and their novel derivatives

Phu Cuong Nguyen,My Tuyen Thi Nguyen,Chang-Kyu Lee,Wang-Hee Lee,Il-Nam Oh,Jae-Han Kim,Soon-Taek Hong,Jong-Tae Park 한국당과학회 2022 한국당과학회 학술대회 Vol.2022 No.07

Maltodextrin in specific length is of great interest because of its wide industrial applications. Previously, we have proven that Pyrococcus furiosus thermostable amylase (PFTA) produces high purity maltoheptaose (G7) from β-cyclodextrin (CD) at early reaction time. However, the production of pure G7 is a cost and time-consuming process. Therefore, this work has designed an optimal continuous process for pure G7 production from β-CD using PFTA with immobilization in a packed-bed reactor (PBR). The optimal conditions determined using the response surface method for the maximized G7-purity of 96.3% were predicted at 4.7 ml/min of flow rate, 1.1% substrate, and 48.7 °C. As a result, the immobilized PFTA in PBR retained 85% of the initial activity after six cycles of 24 h intervals, and the product purity was unchanged. Also, maltohexaose (G6) and maltooctaose (G8) at high purity (92-97%) were produced by continuously supplying CDs to the PFTA-PBR under the same optimized condition of G7. In addition, a new method based on preparative reversed-phase liquid chromatography was developed to purify maltodextrins in specific lengths (DP 3-26) with high purity from the reaction mixture of G6-G8 substrates with Thermotoga maritima maltosyltransferase. On the other hand, novel G7-based sugar esters were also synthesized and investigated for emulsifying properties. As a result, G7-fatty acids (C10–C16) esters were produced with a high conversion yield (90-95%) under the optimal conditions (10% of DMSO, 0.2 of G7/ fatty acids molar ratio, 33.5 U of immobilized Candida antarctica lipase B) for 24 h of incubation at 60 °C. Notable, G7-palmitate (PA) exhibited emulsifying properties better than commercial sucrose-PA ester, especially in acidic conditions. It is feasible that the number of the hydroxyl groups and the size of G7 moiety provide that distinctive property of G7-PA. Therefore, applications of G7-PA in foods, cosmetics, and drug delivery under extreme pH conditions are promising.

A study of anisotropic yield function based on J₂ and J₃ invariants

Phu-Van Nguyen,Jin-Jae Kim,Quoc-Tuan Pham,Young-Suk Kim 한국소성가공학회 2019 한국소성가공학회 학술대회 논문집 Vol.2019 No.10

Vibration control of a vehicle’s seat suspension featuring a magnetorheological damper based on a new adaptive fuzzy sliding-mode controller

Phu, Do Xuan,Choi, Seung-Bok,Lee, Yang-Sub,Han, Moon-Sihk Professional Engineering Publishing Ltd 2016 Proceedings of the Institution of Mechanical Engin Vol. No.

<P>This work presents a new design for adaptive fuzzy sliding-mode control based on two methodologies, namely H control and sliding-mode control, and its control effectiveness. This is achieved by implementing a control scheme for vibration control of a vehicle with a seat suspension on which a magnetorheological damper is installed. The sliding surface of sliding-mode control is analysed by separation into two matrices: a Hurwitz-constants matrix and a constant matrix. These matrices are the basis for establishing the proposed control scheme combined with the H technique. The control scheme consisting of the combination of H control and sliding-mode control is reinforced by a new robustness function featuring an exponential function. In this work, a fuzzy logic model, which is well known to be an excellent model for uncertain dynamic systems, is integrated with the proposed control algorithm. The fuzzy logic model adopted in this work is an interval type-2 fuzzy model featuring fast computation of the output. The effectiveness of the proposed control scheme is evaluated through both computer simulations and experimental realization on a vehicle with a seat suspension which is equipped with a magnetorheological damper. In addition, in this work, two existing adaptive controllers are modified and implemented for comparative work with the proposed control scheme. It is shown that the proposed control scheme exhibits a much better vibration control performance than the two existing adaptive controllers do.</P>

Over-expression of Major Royal Jelly Protein 3 from Apis mellifera in E. coli

Phu Van Nguyen,Ji-Na No,Mi-Sun Yoo,Yong-Ha Park,Byoung-Su Yoon 한국양봉학회 2010 韓國養蜂學會誌 Vol.25 No.3

Seismic Fragility Assessment for A Newly Developed Buried Arch Bridge

Phu Van Dang,허정원,안진희,Achintya Haldar,곽기석 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.11

This study aims to assess the seismic response of a newly developed buried arch bridge system. The proposed buried arch bridge system is comprised of precast concrete panels, external steel outriggers, and steel V-strips to solve the limitation encountered in the storage, transportation, and construction of traditional buried arch structures. The three-dimensional finite element analysis of this arch system is conducted under dynamic analysis emphasizing the frequency content of earthquakes. Then, the fragility curves are suggested for this arch system based on two damage states defined via incremental dynamic analysis. The results show that this proposed arch system is significantly affected under a high frequency content earthquake compared to the low and intermediate ones. Additionally, the arch system deflects the most at the mid-high position rather than at the arch crown. The deflection at the arch crown or at the mid-high position can be used for establishing the fragility curves as they both connect with the failure mechanism of the arch structure.

Design of a novel adaptive fuzzy sliding mode controller and application for vibration control of magnetorheological mount

Phu, Do Xuan,Quoc, Nguyen Vien,Park, Joon-Hee,Choi, Seung-Bok Professional Engineering Publishing Ltd 2014 Proceedings of the Institution of Mechanical Engin Vol. No.

<P>This paper presents vibration control of a mixed-mode magnetorheological fluid-based mount system using a new robust fuzzy sliding mode controller. A novel model of controller is built based on adaptive hybrid control of interval type 2 fuzzy controller incorporating with a new modified sliding mode control. The interval type 2 fuzzy is optimized for computational cost by using enhanced iterative algorithm with stop condition, and a new modified switching surface of sliding mode control is designed for preventing the chattering of the system. The controller is then experimentally implemented under uncertain conditions in order to evaluate robust vibration control performance. In addition, in order to demonstrate the effectiveness of the proposed controller, two fuzzy sliding mode control algorithms proposed by Huang and Chan are adopted and modified. The principal control parameters of three controllers are updated online by adaptation laws to meet requirements of magnetorheological mount system which has two operation modes: flow mode and shear mode. It is shown from experimental realization of three controllers that the proposed control strategy performs the best under uncertain conditions compared with two other modified controllers. This merit is verified by presenting vibration control performances in both time and frequency domains.</P>

Invasive Non-typhoidal <i>Salmonella</i> Infections in Asia: Clinical Observations, Disease Outcome and Dominant Serovars from an Infectious Disease Hospital in Vietnam

Phu Huong Lan, Nguyen,Le Thi Phuong, Tu,Nguyen Huu, Hien,Thuy, Le,Mather, Alison E.,Park, Se Eun,Marks, Florian,Thwaites, Guy E.,Van Vinh Chau, Nguyen,Thompson, Corinne N.,Baker, Stephen Public Library of Science 2016 PLoS neglected tropical diseases Vol.10 No.8

<▼1><P>Invasive non-typhoidal <I>Salmonella</I> (iNTS) infections are now a well-described cause of morbidity and mortality in children and HIV-infected adults in sub-Saharan Africa. In contrast, the epidemiology and clinical manifestations of iNTS disease in Asia are not well documented. We retrospectively identified >100 cases of iNTS infections in an infectious disease hospital in Southern Vietnam between 2008 and 2013. Clinical records were accessed to evaluate demographic and clinical factors associated with iNTS infection and to identify risk factors associated with death. Multi-locus sequence typing and antimicrobial susceptibility testing was performed on all organisms. Of 102 iNTS patients, 71% were HIV-infected, >90% were adults, 71% were male and 33% reported intravenous drug use. Twenty-six/92 (28%) patients with a known outcome died; HIV infection was significantly associated with death (<I>p</I> = 0.039). <I>S</I>. Enteritidis (Sequence Types (ST)11) (48%, 43/89) and <I>S</I>. Typhimurium (ST19, 34 and 1544) (26%, 23/89) were the most commonly identified serovars; <I>S</I>. Typhimurium was significantly more common in HIV-infected individuals (<I>p</I> = 0.003). Isolates from HIV-infected patients were more likely to exhibit reduced susceptibility against trimethoprim-sulfamethoxazole than HIV-negative patients (<I>p</I> = 0.037). We conclude that iNTS disease is a severe infection in Vietnam with a high mortality rate. As in sub-Saharan Africa, HIV infection was a risk factor for death, with the majority of the burden in this population found in HIV-infected adult men.</P></▼1><▼2><P><B>Author Summary</B></P><P>Invasive non-typhoidal <I>Salmonella</I> (iNTS) infections occur when <I>Salmonella</I> bacteria, which normally cause diarrhea, enter the bloodstream and spread through the body. Invasive NTS infections have become a common cause of infection and death in children with malaria and adults with HIV in sub-Saharan Africa. However, it is unknown whether iNTS is as common or as severe outside sub-Saharan Africa. We evaluated over 100 iNTS cases from an infectious disease hospital in southern Vietnam admitted between 2008–2013. We used hospital records to determine the clinical features of iNTS disease and to identify risk factors associated with death and performed typing of the isolated organisms. The majority of patients were HIV positive (72/102, 71%), >90% of patients were adults, 71% were male and 33% reported intravenous drug use. The mortality rate of iNTS patients was 28% (26/92), and HIV infection was a significant risk factor for fatal outcome (<I>p</I> = 0.039). The serovars most commonly identified were <I>S</I>. Enteritidis and <I>S</I>. Typhimurium; <I>S</I>. Typhimurium was found more frequently in HIV-positive individuals (<I>p</I> = 0.003). We report that iNTS disease is a severe infection in Vietnam with a high mortality rate. Similar to sub-Saharan Africa, HIV infection was a strong risk factor for death.</P></▼2>

Enzymatic Synthesis of Pure Maltohexaose from α-Cyclodextrin

Phu Cuong Nguyen,Ji-Yun Kwak,Min-Jee Yoo,Jong-Tae Park,Kwan-Hwa Park 한국당과학회 2016 한국당과학회 학술대회 Vol.2016 No.01

Maltohexaose (G6) is a maltodextrin consisted of six-glucose in α-1,6-glycosidic linkages and essential research tool in food, cosmetic and pharmaceutical. In previous study, we have proven that the possibility of large-scale continuous production of pure maltodextrins from cyclodextrins (CDs) using Pyrococcus furiosus thermostable amylase with immobilization in a packed-bed reactor (PBR). In this study, we used this PBR for G6 production from α-CD. After enzyme reaction, 1-decanol was added to G6 mixture as precipitating agent with a 1:1 ratio of 1-decanol to α-CD. In which, the unreacted α-CD was precipitated, then it was separated by centrifugation. Finally, the G6-product was obtained in homogeneous form and high-purity (95 %). Through this study, we successfully demonstrated the enzymatic synthesis method to produce pure G6 from α-CD.