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Journal of Renewable Materials 2021年第8期9卷 1393-1411页

作者： Nguyen Thi Thanh Thuy le hoang huy Truong Thuy Vy Nguyen Thi Thanh Tam Bien ThiLan Thanh Nguyen Thi My Lan Nong Lam University Ho Chi Minh City Ho Chi Minh City700000Vietnam Industrial University of Ho Chi Minh City Ho Chi Minh City700000Vietnam University of Science Viet Nam National University Ho Chi Minh CityHo Chi Minh City700000Vietnam

In the present study,the biogenic silver nanoparticles have been synthesized using aqueous leaf extract of Plectranthus amboinicus(PA),which acted as both reducing and stabilizing *** PA synthesized silver nanoparticles were blended with carboxymethyl cellulose/polyvinyl alcohol(CMC/PVA)*** prepared AgNPs as well as the biogenic AgNPs incorporated CMC/PVA films were investigated using UV-visible spectrophotometry,Fourier-transform infrared spectroscopy(FT-IR),dynamic light scattering(DLS),scanning electron microscope(SEM),and X–ray diffraction(XRD).The DLS results showed that biogenic AgNPs had the average particle size of 65.70 nm with polydispersity index of *** surface plasmon resonance of AgNPs,which was determined by UV-vis spectrophotometry,showed the value of 410.00 *** results therefore confirmed the reduction Ag+into Ag°and the formation of AgNPs in the *** SEM imaging showed that AgNPs was quasi-spherical and *** XRD peaks at 33.07°,44.19°,64.58°and 77.47°confirmed the crystalline nature and presence of *** CMC/PVA films that incorporated with AgNPs displayed best mechanical strength and morphological properties than the pure CMC/PVA *** film of CMC/PVA-AgNPs exhibited significant antibacterial activities against Bacillus spizizenii,Staphylococcus aureus,Salmonella typhi and Escherichia Coli.

关键词： Carboxymethyl cellulose antibacterial green synthesis silver nanoparticles plectranthus amboinicus polyvinyl alcohol

An exploration of meteorological effects on PM_(2.5) air quality in several provinces and cities in Vietnam

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Journal of Environmental Sciences 2024年第11期145卷 139-151页

作者： Giang Tran Huong Nguyen Luan Thien La huy hoang-Cong Anh hoang le Faculty of Chemistry and Environment Dalat UniversityLam Dong ProvinceVietnam Environmental Protection Agency Lam Dong Province Department of Natural Resources and EnvironmentLam Dong ProvinceVietnam Northern Center for Environmental Monitoring Environmental Pollution Control DepartmentHa Noi CityVietnam Faculty of Environment University of ScienceHo Chi Minh CityVietnam Vietnam National University Ho Chi Minh CityVietnam

Linking meteorology and air pollutants is a key *** study investigated meteorological effects on PM_(2.5)concentration using the advanced convergent cross mapping method,utilizing hourly PM_(2.5)concentration and six meteorological factors across eight provinces and cities in *** demonstrated that temperature(ρ=0.30)and radiation(ρ=0.30)produced the highest effects,followed by humidity(ρ=0.28)and wind speed(ρ=0.24),while pressure(ρ=0.22)and wind direction(ρ=0.17)produced the weakest effects on PM_(2.5)*** theρvalues showed that temperature,wind speed,and wind direction had greater impacts on PM_(2.5)concentration during the dry season whereas radiation had a more influence during the wet season;Southern stations experienced larger meteorological ***,humidity,pressure,and wind direction had both positive and negative influences on PM_(2.5)concentration,while radiation and wind speed mostly had negative *** PM_(2.5)pollution episodes,there wasmore contribution ofmeteorological effects on PM_(2.5)concentration indicated byρ*** contaminated levels,humidity(ρ=0.45)was the most dominant factor affecting PM_(2.5)concentration,followed by temperature(ρ=0.41)and radiation(ρ=0.40).Pollution episodes were pointed out to be more prevalent under higher humidity,higher pressure,lower temperature,lower radiation,and lower wind ***ρcalculation also revealed that lower temperature,lower radiation,and higher humidity greatly accelerated each other under pollution episodes,further enhancing PM_(2.5)*** findings contributed to the literature on meteorology and air pollution interaction.

关键词： Fine particulate matter Air pollution Meteorological effect Convergent cross mapping Causality analysis Vietnam

Machine learning based models for predicting compressive strength of geopolymer concrete

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Frontiers of Structural and Civil Engineering 2024年第7期18卷 1028-1049页

作者： Quang-huy le Duy-Hung NGUYEN Thanh SANG-TO Samir KHATIR hoang le-MINH Amir H.GANDOMI Thanh CUONG-le Center for Engineering Application and Technology Solutions Ho Chi Minh City Open UniversityHo Chi Minh 700000Vietnam Institute of Civil Engineering Ho Chi Minh City University of TransportHo Chi Minh 700000Vietnam Faculty of Engineering&Information Technology University of Technology SydneyUltimoNSW 2007Australia

Recently,great attention has been paid to geopolymer concrete due to its advantageous mechanical and environmentally friendly *** effort has been made in experimental studies to advance the understanding of geopolymer concrete,in which compressive strength is one of the most important *** facilitate engineering work on the material,an efficient predicting model is *** this study,three machine learning(ML)-based models,namely deep neural network(DNN),K-nearest neighbors(KNN),and support vector machines(SVM),are developed for forecasting the compressive strength of the geopolymer concrete.A total of 375 experimental samples are collected from the literature to build a database for the development of the predicting models.A careful procedure for data preprocessing is implemented,by which outliers are examined and removed from the database and input variables are standardized before feeding to the fitting *** standard K-fold cross-validation approach is applied for evaluating the performance of the models so that overfitting status is well managed,thus the generalizability of the models is *** effectiveness of the models is assessed via statistical metrics including root mean squared error(RMSE),mean absolute error(MAE),correlation coefficient(R),and the recently proposed performance index(PI).The basic mean square error(MSE)is used as the loss function to be minimized during the model fitting *** three ML-based models are successfully developed for estimating the compressive strength,for which good correlations between the predicted and the true values are obtained for DNN,KNN,and *** numerical results suggest that the DNN model generally outperforms the other two models.

关键词： geopolymer concrete compressive strength prediction machine-learning based model deep neural network K-nearest neighbor support vector machines

Finite element analysis of functionally graded sandwich plates with porosity via a new hyperbolic shear deformation theory

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Defence Technology（防务技术） 2022年第3期18卷 490-508页

作者： Pham Van Vinh le Quang huy Department of Solid Mechanics Le Quy Don Technical University236 Hoang Quoc VietHanoiViet Nam Institute of Techniques for Special Engineering Le Quy Don Technical University236 Hoang Quoc VietHanoiViet Nam

This study focusses on establishing the finite element model based on a new hyperbolic sheareformation theory to investigate the static bending,free vibration,and buckling of the functionally graded sandwich plates with *** novel sandwich plate consists of one homogenous ceramic core and two different functionally graded face sheets which can be widely applied in many fields of engineering and defence *** discrete governing equations of motion are carried out via Hamilton’s principle and finite element *** computation program is coded in MATLAB software and used to study the mechanical behavior of the functionally graded sandwich plate with *** present finite element algorithm can be employed to study the plates with arbitrary shape and boundary *** obtained results are compared with available results in the literature to confirm the reliability of the present ***,a comprehensive investigation of the effects of several parameters on the bending,free vibration,and buckling response of functionally graded sandwich plates is *** numerical results shows that the distribution of porosity plays significant role on the mechanical behavior of the functionally graded sandwich plates。

关键词： Functionally graded sandwich plates Porous plates Hyperbolic shear deformation theory Bending analysis Free vibration analysis Buckling analysis

In vitro and in silico studies of salicylic acid on systemic induced resistance against bacterial leaf blight disease and enhancement of crop yield

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Journal of Integrative Agriculture 2023年第1期22卷 170-184页

作者： Wannaporn THEPBANDIT Narendra Kumar PAPATHOTI Jayasimha Rayulu DADDAM Nguyen huy hoang Toan le THANH Chanon SAENGCHAN Kumrai BUENSANTEAI School of Crop Production Technology Suranaree University of TechnologyNakhon Ratchasima 30000Thailand Department of Animal Science Agriculture Research OrganizationRishon Lezion 7505101Israel Department of Plant Protection Can Tho UniversityCan Tho 900000Vietnam

Salicylic acid(SA)is an effective elicitor to promote plant defenses and *** study aimed to investigate rice(Oryza sativa L.)*** Dawk Mali 105 treated with salicylic acid(SA)-Ricemate as an enhanced plant protection mechanism against bacterial leaf blight(BLB)disease caused by Xanthomonas oryzae ***(Xoo).Results indicated that the use of SA-Ricemate as a foliar spray at concentrations of more than 100 mg L^(-1)can reduce the severity of BLB disease by 71%.SA-Ricemate treatment also increased the hydrogen peroxide(H_(2)O_(2))content of rice leaf tissues over untreated samples by 39–61%.Malondialdehyde(MDA)in rice leaves treated with SA-Ricemate also showed an increase of 50–65%when comparing to non-treated *** differential development of these defense compounds was faster and distinct when the SA-Ricemate-treated rice was infected with Xoo,indicating plant-induced ***,SA-Ricemate elicitor at a concentration of 50–250 mg L^(-1)was correlated with a substantial increase in the accumulation of total chlorophyll content at 2.53–2.73 mg g^(-1)of fresh weight which suggests that plant growth is activated by *** catalase-and aldehyde dehydrogenase-binding sites were searched for using the CASTp server,and the findings were compared to the *** was used to design and optimize SA,which was then docked to the catalase and aldehyde dehydrogenase-binding domains of the enzymes using the GOLD 3.0.1 *** is shown in several docked conformations with the enzymes catalase and aldehyde *** three catalase amino acids(GLN7,VAL27,and GLU38)were discovered to be involved in the creation of a strong hydrogen bond with SA when SA was *** this mechanism,the aldehyde dehydrogenase amino acids LYS5,HIS6,and ASP2 were all implicated,and these amino acids created strong hydrogen bonds with *** field conditions,SA-Ricemate significantly reduced disease severity by 78%and the total grain yield was si

关键词： bacterial leaf blight crop yield in vitro in silico rice defense salicylic acid

Comparative study on water-soluble inorganic ions in PM2.5 from two distinct climate regions and air quality

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Journal of Environmental Sciences 2020年第2期32卷 349-360页

作者： Duong Huu huy le Tu Thanh To Thi Hien Norimichi Takenaka Faculty of Food Science and Technology Ho Chi Minh City University of Food Industry140 Le Trong Tan StreetTan Phu DistrictHo Chi Minh CityViet Nam Faculty of Environment University of ScienceVietnam National University–Ho Chi Minh City227 Nguyen Van Cu StreetDistrict 5Ho Chi Minh CityViet Nam Graduate School of Humanities and Sustainable System Sciences Osaka Prefecture University1-1 Gakuen-choNaka-kuSakai-shiOsaka 599-8531Japan

Recently, air quality has significantly improved in developed country, but that issue is of concern in emerging megacity in developing *** this study, aerosols and their precursor gas were collected by NILU filter pack at two distinct urban sites during the winter and summer in Osaka, Japan and dry and rainy seasons in Ho Chi Minh City(HCMC),*** aims are to investigate the contribution of water-soluble inorganic ions(WSIIs) to PM2.5, thermodynamic characterization and possible formation pathway of secondary inorganic aerosol(SIA).The PM2.5 concentration in Osaka(15.8 μg/m^3) is lower than that in HCMC(23.0 μg/m^3), but the concentration of WSIIs in Osaka(9.0 μg/m^3) is two times higher than that in HCMC(4.1 μg/m^3).Moreover, SIA including NH4^+, NO3^-and SO4^2-are major components in WSIIs accounting for 90% and 76%(in molar) in Osaka and HCMC,*** models were used to understand the thermodynamic characterization of urban ***, statistical analysis results indicate that very good agreement(R2> 0.8) was found for all species, except for nitrate aerosol in *** found that when the crustal species present at high amount, those compositions should be included in model calculation(*** the HCMC situation).Finally, we analyzed the characteristics of NH4^+– NO3^-– SO4^2-system.A possible pathway to produce fine nitrate aerosol in Osaka is via the homogeneous reaction between NH3 and HNO3, while nonvolatile nitrate aerosols can be formed by the heterogeneous reactions in HCMC.

关键词： Water-soluble inorganic ions Thermodynamic model PM2.5

An analytical model for cross-Kerr nonlinearity in a four-level N-type atomic system with Doppler broadening

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Chinese Physics B 2022年第2期31卷 314-319页

作者： Dinh Xuan Khoa Nguyen huy Bang Nguyen le Thuy An Nguyen Van Phu le Van Doai Vinh University 182 Le Duan StreetVinh CityVietna

We present an analytical model for cross-Kerr nonlinear coefficient in a four-level N-type atomic medium under Doppler *** model is applied to87 Rb atoms to analyze the dependence of the cross-Kerr nonlinear coefficient on the external light field and the temperature of atomic *** analysis shows that in the absence of electromagnetically induced transparency(EIT)the cross-Kerr nonlinear coefficient is zero,but it is significantly enhanced when the EIT is *** means that the cross-Kerr effect can be turned on/off when the external light field is on or ***,the amplitude and the sign of the cross-Kerr nonlinear coefficient are easily changed according to the intensity and frequency of the external light *** amplitude of the cross-Kerr nonlinear coefficient remarkably decreases when the temperature of atomic medium *** analytical model can be convenient to fit experimental observations and applied to photonic devices.

关键词： electromagnetically induced transparency Kerr nonlinear effect Doppler effect

Potential application of high pressure carbon dioxide in treated wastewater and water disinfection:Recent overview and further trends

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Journal of Environmental Sciences 2015年第10期27卷 38-47页

作者： huy Thanh Vo Tsuyoshi Imai Truc Thanh Ho Thanh-Loc Thi Dang Son Anh hoang Division of Urban Infrastructural Engineering Mien trung University of Civil Engineering Division of Environmental Science and Engineering Yamaguchi University

Recently emerging disadvantages in conventional disinfection have heightened the need for finding a new solution. Developments in the use of high pressure carbon dioxide for food preservation and sterilization have led to a renewed interest in its applicability in wastewater treatment and water disinfection. Pressurized CO2 is one of the most investigated methods of antibacterial treatment and has been used extensively for decades to inhibit pathogens in dried food and liquid products. This study reviews the literature concerning the utility of CO2 as a disinfecting agent, and the pathogen inactivation mechanism of CO2 treatment is evaluated based on all available research. In this paper, it will be argued that the successful application and high effectiveness of CO2 treatment in liquid foods open a potential opportunity for its use in wastewater treatment and water disinfection. The findings from models with different operating conditions（pressure, temperature, microorganism, water content, media …） suggest that most microorganisms are successfully inhibited under CO2 treatment. It will also be shown that the bacterial deaths under CO2 treatment can be explained by many different ***, the findings in this study can help to address the recently emerging problems in water disinfection, such as disinfection by-products（resulting from chlorination or ozone treatment）.

关键词： High pressure CO2 Inactivation effect Inactivation mechanism

Effects of NaOH Concentrations on Properties of the Thermal Power Plant Ashes-Bricks by Alkaline Activation

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Journal of Wuhan University of Technology(Materials Science) 2020年第1期35卷 131-139页

作者： Ngo Si-huy le Thi Thanh-Tam huynh Trong-Phuoc Department of Engineering and Technology Hong Duc UniversityNo.565Quang Trung StreetDong Ve WardThanh Hoa City 440000Viet Nam Department of Rural Technology College of Rural DevelopmentCan Tho UniversityCampus II3/2 StreetNinh Kieu DistrictCan Tho City 900000Viet Nam

The use of the thermal power plant ashes including fly ash(FA) and bottom ash(BA) for producing unfired building bricks(UBB) using sodium hydroxide(NaOH) solution as an alkaline activator was investigated. A low applied forming pressure of 0.5 MPa and various NaOH concentrations of 5, 8, 10, and 12 M were used for the preparation of brick samples with different solution-to-binder(S/B) ratios of 0.35 and 0.40. The bricks were subjected to various test programs with reflecting the effect of both NaOH concentrations and S/B ratios on the brick’s properties. The compressive strength, unit weight, ultrasonic pulse velocity, and thermal conductivity of bricks increased with increasing NaOH concentration, whereas the contrary trend was found with increasing S/B ratio. Also, the water absorption of bricks was observed to reduce with increasing NaOH concentration and decreasing S/B ratio. As the results, the combined utilization of both low forming pressure and coal power plant ashes can produce the UBBs with low unit weight, low heat conductivity, and acceptable strength and water absorption rate as stipulated by TCVN 6477-2016. Furthermore, the outcomes of chemical analysis and microstructure observation also demonstrate that a high concentration of the Na OH promoted the geopolymerization process. Notably, the use of NaOH solution of either 10 M or above is recommended for the production of UBBs, which are classified as grade M5.0 or higher.

关键词： unfired building brick fly ash bottom ash thermal power plant ashes sodium hydroxide solution low forming pressure

Comparative Study of Light Manipulation in Three-level Systems Via Spontaneously Generated Coherence and Relative Phase of Laser Fields

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Communications in Theoretical Physics 2019年第8期71卷 947-954页

作者： Nguyen huy Bang le Nguyen Mai Anh Nguyen Tien Dung le Van Doai Vinh University 182 Le Duan Street Vinh City Vietnam Nong Lam University Ho Chi Minh City Vietnam (Received March 21 2019revised manuscript

We present a comparative study of the control of group velocity in three-level atomic systems including Λ-, Ladder-, and V-types via spontaneously generated coherence(SGC) and relative phase of laser *** the steady regime, expressions of group index are derived as an analytical function of controllable parameters related to SGC and relative *** is shown that the group velocity can be further slowed down or speeded up under SGC in which modifications of group velocity due to the SGC in Λ-and V-systems are stronger than that in *** particular, when interference strength of SGC p increases from 0.7 to 1.0, the light propagation is switched from superluminal to subluminal modes(for Λ-and Ladder-systems) or from subluminal to superluminal modes(for Vsystem).In the presence of relative phase, the group velocity changes between subluminal and superluminal modes with a period of 2π.In resonant region, the largest positive value of group index reaches at the relative phase φ=π while the largest negative value of group index reaches at φ= 0 and 2π for the Λ-and Ladder-systems, otherwise, for the V-system the largest positive group index occurs at φ= 0 and 2π, and the largest negative group index occurs at φ=π.

关键词： electromagnetically induced transparency spontaneously generated coherence group velocity