bluuebunny/crossref_metadata_2025 huggingface dataset:
FABRICATION OF CURCUMIN LOADED NANO POLYCAPROLACTONE/CHITOSAN NONWOVEN FABRIC VIA ELECTROSPINNING TECHNIQUE
Authors: Hoang Minh Son
Published: April 2018

Cucurmin loaded poly e–caprolactone/chitosan (PCL/CTS) nanoscale nonwoven fabric was successfully fabricated using electrospinning, a facial and efficient method. The surface tensions of PCL/CTS blend solutions in various ratios were measured to evaluate the influence of PCL/CTS ratio on fibers formation. The effects of process parameter such as the applied voltage, tip–collector distance and the solution flow rate on the fiber generation and morphology of final fiber were optimized. Nanofibers morphology and structure were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. The prepared fibers had a smooth surface and fine morphology. The diameter of fibers ranges from 200  nm to 400 nm. The release kinetics of curcumin loaded samples were also analyzed via in vitro technique. Results demonstrated that the polycaprolactone/chitosan–based nanofibers encapsulate curcumin is a potential material for wound healing acceleration.
REMOVAL OF Cd(II) FROM WATER BY USING GRAPHENE OXIDE–MnFe2O4 MAGNETIC NANOHYBRIDS
Authors: Hieu Nguyen Huu
Published: April 2018

In this work, graphene oxide–manganese ferrite (GO–MnFe2O4) magnetic nanohybrids were synthesized by co–precipitation technique. The adsorption properties of GO–MnFe2O4 for efficient removal of Cd(II) from contaminated water were investigated. The nanohybrids were characterized by using X–ray diffraction, Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller specific surface area (BET), transmission electron microscopy, and vibrating sample magnetometry (VSM). VSM result showed the high saturation magnetization values Ms = 27.1 emu/g, the BET specific surface area was 84.236 m2/g. Adsorption experiments were carried out to evaluate the adsorption capacity of the GO–MnFe2O4 magnetic nanohybrids and compared with MnFe2O4 nanoparticles and GO nanosheets. The equilibrium time for adsorption of Cd(II) onto the nanohybrids was 240 minutes. Experimental adsorption data were well–fitted to the Langmuir isotherm and the pseudo–second–order kinetic equation. The experimental results showed that adsorption of Cd(II) using GO–MnFe2O4 magnetic nanohybrids was better than MnFe2O4 and GO with a maximum adsorption capacity of 121.951 mg/g at pH 8.  Reusability, ease of magnetic separation, high removal capacity, and fast kinetics lead the GO–MnFe2O4 nanohybrids to be promising adsorbents for removal heavy metals from contaminated water.
SURVEY ON ANTIBACTERIAL ACTIVITY OF ACRYLATE – STYRENE COPOLYMER CONTAINING QUATERNARY NITROGEN ATOMS
Authors: Dang Canh Nguyen Vo
Published: April 2018

In this research acrylate – styrene copolymer containing quaternary nitrogen atoms was synthesized by a bulk copolymerization method according to free radical mechanism. Antibacterial activity of this resin was examined by changing parameter values such as: types and amount of the neutralized agents, temperature of the neutralization reaction, etc. The antibacterial properties of the acrylate – styrene copolymer were evaluated via the agar diffusion test. In addition, the molecular structure of the copolymer was performed in Fourier transformation infrared (FTIR) spectroscopy. Besides that, the hydrogels from the acrylate – styrene copolymer were also examined on their antibacterial properties. As results, the copolymer showed the highest antibacterial activities with the ratio of ammonia to acrylic acid about 0.8:1 and the neutralizing temperatures at 60 °C.
SYNTHESIS OF MICROCAPSULES FROM PREPOLYURETHANES
Authors: Thai Ha La Thi
Published: April 2018

Polyurethane (PU) microcapsules containing toluene diisocyanate (TDI) healing agent were synthesized by mixing PU with chain extender ethyleneglycol (EG) via interfacial polymerization of oil–in–water (gum arabic emulsifier). The morphology and size of the capsules greatly depend on a variety of factors including dispersion speed and emulsifier ratio. The preparation of PU prepolymer and microcapsulation of TDI are presented. The diameter of smooth spherical microcapsules ranged from 93, 160 and 239 µm are produced by varying the agitation rate from 800 rpm to 1200 rpm. The core content of microcapsules is influenced by the ratio of chlorobenzene (CB) solvent in oil phase. The microcapsules have about 40.5 wt% of core which are capable of application in self–healing coatings when using 20 wt% CB and 17.5 wt% emulsifer ratio.
A SYNTHESIS OF SOLID ACID CATALYSTS FOR USING IN HYDROLYSIS OF CELLULOSE FROM RICE STRAW INTO GLUCOSE
Authors: Phan T-Que Phuong
Published: April 2018

In this study, a carbon–based solid acid catalyst was prepared via hydrothermal carbonization method (HTC) using glucose and pyrolysed waste tyre as carbon precursors and aqueous solution of H2SO4 as sulfonation agent. Prepared catalysts were characterized by X–ray diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared FT–IR and Brunauer–Emmett–Teller (BET). As the result, catalysts were manufactured with the appropriate physical and chemical characteristics and high acidity.
CATALYST–FREE GROWTH OF WELL–ALIGNED ZnO NANOWIRES ON GRAPHENE/Si SUBSTRATEBY THERMAL EVAPORATION
Authors: Khai Tran Van
Published: April 2018

Vertically well–aligned ZnO nanowire (NW) arrays with high density were directly synthesized on graphene/Si substrate by thermal evaporation of zinc powder without catalysts or additives. The ZnO NWs were characterized by field emission scanning electron microscopy (FE–SEM), high resolution transmission electron microscopy (HRTEM), X–ray diffraction (XRD), photoluminescence (PL), and Raman spectroscopy. The results showed that the obtained ZnO NWs have diameters in the range of 300–350 nm with lengths of several tens micrometers. The prepared ZnO NWs are of a single crystal, which have a hexagonal wurtzite crystal structure with c–axis (002) orientation growth perpendicular to the substrate surface. The NW arrays had a good crystal quality with excellent optical properties, indicating a sharp and strong ultraviolet emission at 380 nm, and a weak visible emission at around 516 nm.
ENZYMATIC PREPARATION OF MODULATED–BIODEGRADABLE HYDROGEL NANOCOMPOSITES BASED CHITOSAN/GELATIN AND BIPHASIC CALCIUM PHOSPHATE NANOPARTICLES
Authors: Thinh Nguyen Tien
Published: April 2018

In the study, injectable chitosan–4 hydroxyphenylacectamide acid (CHPA) and gelatin–tyramine (GTA)–based hydrogels were enzymatically prepared, in which could encapsulate biphasic calcium phosphate nanoparticles (BCP NPs) for enhancing bone regeneration. The in situ formation of hydrogel composite was varied from 35 to 80 seconds depending on concentration of H2O2. Collagenase–mediated biodegradation of the hydrogel composite could be modulated from 3 days to over one month depending on amount of the formulated CHPA. Live/dead cell viability assay indicated that the hydrogel composite enhanced bone marrow mesenchymal stem cells (MSCs). The obtained results show a great potential of the hydrogel composites for bone regeneration due to its adjustable biodegradation, biocompatibility and enhancement in new bone formation.
ELECTROSPRAY METHOD: PROCESSING PARAMETERS INFLUENCE ON MORPHOLOGY AND SIZE OF PCL PARTICLES
Authors: Nguyen Vu Linh Viet
Published: April 2018

The polymeric microparticles using electrospray technique have been used effectively as the drug carrier, whereby controlled release of drug. The electrosprayed particles morphology and size dictated the degradation of polymer matrix, therefore they influenced the release profile from drug loaded microparticles. The effects of electrospray processing parameters (flow rate, applied voltage and distance from the tip of needle to collector) on morphology and size of polycaprolactone (PCL) particles were investigated by scanning electron microscopy (SEM) and ImageJ software. In this research, the PCL solution was prepared by dissolving PCL in Dichloromethane at 4.5 % solution. In addition, processing parameters such as the flow rate (0.5 mL/h, 1 mL/h, 1.5 mL/h, 2 mL/h and 4 mL/h), the applied voltage (15 kV, 18 kV and 24 kV) and the collecting distance (15 cm, 20 cm, and 25 cm) were changed to examine the effects of them on size and morphology of PCL particles. The results indicated that at the suitable electrospraying parameters (18 kV, 1.5 mL/h, 20–25 cm), microparticles have obtained the uniform and stable morphology while at higher flow rate (2 mL/h and 4 mL/h), the particles were deformed and had bigger size.
TAYLOR CONE–JET MODE IN THE FABRICATION OF ELECTROSPRAYED MICROSPHERES
Authors: Nguyen - Vu Viet Linh
Published: April 2018

In this study, electrospray modes were investigated to clarify their effects on the morphology and size of polycaprolactone (PCL) particles. The result indicated that electrosprayed microspheres with homogeneous and stable morphology were fabricated by using cone–jet mode and suitable electrospray processing parameters. Besides, the PCL solution was created by dissolving in dichloromethane with different concentrations such as 3.5%, 4%, 4.5% and 5%. The scanning electron microscopy (SEM) micrographs pointed that electrosprayed PCL microspheres were formed by using 4.5 % polymer solution. In addition, the reproducible and homogeneous morphology of PCL microparticles were obtained at the following set of parameters: applied voltage of 18 kV, flow rate of 1.5 mL/h and distance tip to collector of 20 cm. Moreover, at the collecting distance of 15–25 cm, the flow rate of 1.2–1.8 mL/h and applied voltage of 18 kV the cone–jet mode was generated. It was an effective electrospray mode to create stable and homogeneous microspheres.
SYNTHESIS AND ELECTROCHEMICAL PROPERTIES OF MESOPOROUS CARBON SUPPORTED WELL–DISPERSED COBALT OXIDES NANOPARTICLES
Authors: Tu Nguyen Van
Published: April 2018

In this article, well–dispersed cobalt oxide nanoparticles supported on mesoporous carbon (CMK–3) have been successfully synthesized. The composites were characterized by field emission scanning electron microscopy, transmission electron microscopy, X–ray diffraction and nitrogen adsorption–desorption analysis. The results have confirmed that, at a cobalt loading of 15 wt%, the composites have not only retained mesoporous structure of the support but also shown a good control of dispersed cobalt oxide nanoparticles with size of ~4 nm. The electrochemical property tests for the synthesized samples have shown significant improvement compared to the blank carbon (CMK–3) without cobalt oxide incorporation.
TRA BAC ACTIVATED CARBON USED AS ELECTRODE MATERIAL IN AQUEOUS SUPERCAPACITOR
Authors: Tran Van Man
Published: April 2018

Carbon materials i.e. activated carbon, carbon aerogel, carbon nanotubes (CNTs)… store a high electric power and a great stable cyclability when they are used as electrode materials in electrical double–layers capacitor (EDLC). In this work, activated carbon from coconut shells which was cooperatively provided by the Tra Bac Joint Stock Corporation–TRABACO was investigated as electrode materials in EDLC. Raw carbon material with large particle size was crushed and sieved to obtain a 43 µm grain size fraction for electrochemical characterization. The symmetric EDLC configuration based on Tra Bac carbon was tested in Swagelok–type cell using KOH electrolyte in the potential range 0–1 V. The CV curves indicated that charges can be stored enormously with a high reversibility and stability. The high performance of EDLC based carbon in KOH electrolyte could be further improved by variation of electrode composition. The rate capability of the material was also studied under different current ranges. In our best results, a specific capacitance of 20 F/g was obtained at the charge–discharge current of 1 A/g. Even at very high applied current range, the capacitance dropped slowly, less than fifteen percent.
SYNTHESIS OF ZINC OXIDE/GRAPHENE OXIDE NANOCOMPOSITES AS ANTIBACTERIAL MATERIALS AGAINST STAPHYLOCOCCUS AUREUS AND ESCHERICHIA COLI
Authors: Hieu Nguyen Huu
Published: April 2018

New materials with good antibacterial activity and less toxicity to other species have attracted numerous research interests. Modified Hummers method was used for preparing graphene oxide (GO). Zinc oxide/graphene oxide (ZnO/GO) nanocomposites were synthesized with three different ratios (0.5:1, 1:1, and 2:1) by solution precipitation method. The ZnO/GO nanocomposites were characterized by Fourier transform infrared spectroscopy, X–ray diffraction, Raman spectroscopy, Brunauer–Emmett–Tellerspecific surface area, and transmission electron microscopy image. The characterization results showed that ZnO nanoparticles with a mean size of 12–18 nm were randomly decorated on the surfaces and edges of GO sheets. ZnO/GO 1:1 with a high specific surface area of 65 m2/g was obtained. The antibacterial activity of ZnO, GO, and ZnO/GO was tested against Gram negative bacteria escherichia coli (E. coli) and Gram positive bacteria staphylococcus aureus (S. aureus) using well diffusion method. The test results confirmed that antibacterial activity of ZnO/GO was higher than that of GO and ZnO. Additionally, the ZnO/GO with the ratio of 1:1 is the strongest activity and more active against S. aureus than against E. coli and minimal inhibitory concentration (MIC) value of ZnO/GO 1:1 is 80 µg/mL for S. aureus and 160 µg/mL for E. coli. This novel nanocomposite could be used as a potential material for antimicrobial application.
GREEN GROWTH PREDICTION OF HO CHI MINH CITY BY THE GREY THEORY MODEL
Authors: Than Nguyen Hien
Published: April 2018

The green growth prediction plays an important role to assess and monitor the growth rate of a local region. Managers and researchers can make timely adaptation policy to improve and innovate economic, cultural and environmental performance to impulse the green growth. The study used the methods such as the multiple criteria analysis, analytic hierarchy process, principal component analysis, and the grey theory model to build and integrate green growth indicators into the green growth index. The green growth index was developed by 9 subjects and 18 indicators. The data of study were collected a period of seven years from 2009 to 2015. The results of study indicated that almost districts increased the green growth index. District 1 and District 5 reached at high green growth level about 60 score, while others were classified into average green growth level. The results of green growth prediction of districts in Ho Chi Minh City also showed that the green growth index will lightly increase from 2016 – 2020.
RESEARCH ON THE ABILITY OF HANDLING AMMONIA CONTAMINATED AIR STREAM BY ACTIVATED CARBON MATERIALS FROM COCONUT FIBER (AC-1) AND PEANUT HUSK (AC-2), IMPREGNATED WITH ZnCl2
Authors: Kim Anh Nguyen Thi
Published: April 2018

This research aimed to investigate the ability of handling ammonia emission from waste gas by adsorption methods. The absorbents were activated carbon materials, which were made from coconut fiber (AC-1) and peanut husk (AC-2), impregnated with ZnCl2. Both of these materials have shown their abilities to remove NH3 (over 90 % efficiency) at the concentration of about 9000 ppm, while the removal efficiency of commercial activated carbon (AC-3) was 70 %. At the inlet concentration of about 3000 ppm, the maximum ammonia removal efficiency was 96.23 % when using AC-1 and 97.74 % using AC-2. The saturation time of each activated carbon was also examined. At inlet concentration of 2800 – 3200 ppm with gas flow rate was 0.4 L.min-1 and 5 g in mass material, the ammonia removal efficiencies of AC-1 and AC-2 were maintained at 80 % lasting for 600 minutes, but the efficiency of AC-3 rapidly decreased to 30 %. In all experiments, the activated carbon that made from peanut husk (AC-2), impregnated with ZnCl2 showed higher performance than one made from coconut fiber (AC-1) and commercial activated carbon (AC-3).
IMPROVEMENT OF SOIL QUALITY, PREVENTION OF PLANT DISEASES AND YIELD INCREASE OF BLACK PEPPER AND COFFEE USING POLYFA-TN3
Authors: Thuy Hoai Pham Thi
Published: April 2018

In the current study, we used bio-organic product POLYFA-TN3 including beneficial indigenous microorganisms isolated in Tay Nguyen to improve soil quality, prevent plant diseases, and increase the yield of black pepper and coffee in Dak Lak province. Experimental results showed the efficiency of using POLYFA-TN3 on improvement of soil quality. Almost parameters of soil were increased after using POLYFA-TN3, of which soluble N, K, and P were significantly increased. Using POLYFA-TN3 also reduced plant diseases of black pepper and coffee such as yellow leaf, slow wilt decline, anthracnose, Phytophthora root rot, coffee rust. Using 2.0 kg POLYFA-TN3/tree post showed that plant diseases dropped to 0.5 - 7.53 % for black pepper, and 0 % for coffee. In addition, the yield of black pepper and coffee was significantly increased, with 35.2 % and 31.1 %, respectively. Our study indicated that the bio-organic product POLYFA-TN3 as a potential product for improvement of soil quality, crop yield, and prevention of plant diseases.
GAS EMISSIONS AND MUTAGENIC EFFECTS OF DIESEL AND BIODIESEL FUELS
Authors: Thang Phan Quang
Published: April 2018

The Ames test has been used to evaluate the mutagenic effect of exhaust gas using diesel and biodiesel fuels (BDFs) from power generator. The Salmonella typhimurium (TA98 and TA100 tester strain) were cultured because of the most sensitive for organic pollutant. The direct sampling from gas emission for Ames test was the first time proposed. Six low molecular-weight methyl esters (LMW-MEs) found in exhaust gas when using biofuels have been tested to reveal that they are not mutagenic but toxic. The quality control standards such as dimethyl sulfoxide (DMSO) and sodium azide (NaN3) were used as negative and positive control in all culture processes. DMSO is the best adsorbent to trap the pollutants in exhaust gas. The mutagenic effects of Diesel fuel (DF) with Jatropha BDF (JCO) and waste cooking oil BDF (WCO) have been evaluated. The highest mutagenicity of WCO was observed in both TA 98 and TA100 testers strain. For the same engine, the mutagenic test result is different between two kinds of BDFs. BDFs showed increased mutagenicity higher than DF with WCO>JCO>DF. The number of revertant colonies are 623>508>424 for TA100 and 66>50>41 for TA98, respectively.
DIATOM COMPOSITION IN THE RED RIVER NEAR SON TAY, HA NOI
Authors: Thu Hang Hoang Thi
Published: April 2018

This study represents data on diatom composition in water samples collected in the Red River near Son Tay town, Hanoi. Diatom samples were selected from marcophyte and stone surfaces during dry season of 2014. 79 diatom species belonging to 8 families were identified. The most species rich genera are Nitzchia (16 species), Navicula (14 species), Gomphonema                 (5 species). There are five diatom species which are dominant in Red River diatom community including Navicularecens (30 % of the total community), Nitzschiapalea (9.3 %), Synedra fasciculate (8.1 %), Luticola minor (5 %) and Gomphonemaparvulum (2.8 %). The Oligosaprobous and α -m esosaprobous diatom taxa make up only around 3% and to 20 % of the total community. However, polysaprobous  and ß- mesosaprobous taxa dominate in the Red River accounted 13 to 51 % total community.
GAS–PARTICLE PARTITIONING OF POLYCYCLIC AROMATIC HYDROCARBONS - PAHs IN AMBIENT AIR IN HOCHIMINH CITY
Authors: Thien Chi Nguyen Doan
Published: April 2018

This research conducted an analysis of 14 Polycyclic Aromatic Hydrocarbons (PAHs) in gas and particle-phase in ambient air in Hochiminh City to investigate their occurence and the gas/particle distribution. Gas and particle samples were collected from June to August 2015 in Hochiminh City and PAHs were treated and analyzed using high performance liquid chromatography with fluorescence detection (HPLC/FLD). Results showed that average concentration of 14 PAHs were from 6.4 to 29.8 ng/m3 and from 50.7 to 133 ng/m3 in particle-phase and in gas-phase, respectively. The concentration of PAHs in the gas-phase accounted for more than 80% of total PAHs concentration in which low molecular weight PAHs as the dominant PAHs. Meanwhile, high molecular weight PAHs distributed mainly in particle-phase. The particle-phase fraction Φ was obtained to understand the partitioning.
ASSESSMENT OF THE ROOF - HARVESTED RAINWATER QUALITY IN SOME SUBURB DISTRICTS, HANOI, VIET NAM
Authors: Ha Nguyen Thi
Published: April 2018

In this paper, the quality of roof harvested rainwater in Dan Phuong, Phuc Tho and Ung Hoa districts, Ha Noi city was assessed. Roof-harvested rainwater were taken in 2 campaigns (November 2015 and April 2016) then analyzed according to the QCVN 01:2009/BYT. The findings showed that in the studied districts, rainwater was collected from the tile, concrete, fibro cement and metal roofing, of which tile roof is the most common one which accounted for 65.6 %. The quality of roof-harvested rainwater in general was rather good. However, parameters including pH, permanganate value, total coliform and Ecoli did not meet the standards. The pH values obtained were almost in the basic range, of which 38/90 samples (42.2 %) were greater than 8.5 and exceeded the standard (QCVN 01:2009/BYT), only 4 samples had acidic water with pH around 4.5. For permanganate value, they ranged from 0.33 to 5.61 mg/L with the number of samples exceeded the permitted standard reaching 30/90 and 17/90 samples in the 1st and 2nd campaign, respectively. In the 1st campaign, the total coliforms and E.coli were detected in 75 and 72 % of the roof harvested rainwater samples, respectively; while in the 2nd campaign these numbers were 62 and 38 %, respectively.
ASSESSING THE VARIATION OF THE DRY SEASON’S SURFACE TEMPERATURE IN BINH DUONG PROVINCE FROM 2002 TO 2016 BY APPLYING THERMAL REMOTE SENSING
Authors: Anh Tuyet Nguyen Huynh
Published: April 2018

Thermal remote sensing with its own concepts and potentials has presented a variety of applications in the atmosphere and land surface temperature (LST) variation detection. The objective of this study is to access the LST variation in the dry season of Binh Duong province for understanding the effect of land-use change on the microclimate conditions. The spectral radiation value was determined from gray-scale of thermal infrared images of Landsat 7 ETM+ and Landsat 8 OLI/TIRs, followed by the LST calculation. Results showed that the LST in dry season decreased approximately 1.5 °C over the past 15 years from 30.8 °C in the year 2002 to 29.3 °C in the year 2016, due to a large area of newly planted land of industrial trees changed into mature ones in 2016. The area, in which temperature increased corresponding to 16.6 % of the natural square, has developed rapidly with new industrial parks, urban areas, and vacant land areas. Therefore, the Government should have solutions to promote its positive side and mitigate its negative side by a suitable land-use structure in order to both develop the economic continuously and help to mitigate the climate change effects.
GREENHOUSE GASES EMISSION IN U MINH THUONG NATIONAL PARK, KIEN GIANG PROVINCE
Authors: Kim Thoa Nguyen Thi
Published: April 2018

This study was conducted to examine the CH4 emission in the core zone and the effects of water and soil physical and chemical characteristics and water depth on CH4 emission in U Minh Thuong National Park, Kien Giang Province. The study was carried out from September, 2016 to November, 2016. The CH4 was collected by closed chambers. The results showed that the soil had a low pH (3.89 - 5.12), a high total phosphorus (0.1 % P2O5) and lower potential redox (from -186 to -145 mV). The organic matter (54.6 %) and total nitrogen (1.15 %) were high in thick peat layers. The organic matter (2.15 - 3.93 %) and total nitrogen (0.1 %) were low in thin or no peat layer. The surface water was polluted by organic matter and was not suitable for domestic use (QCVN 08-MT: 2015/BTNMT column A2). CH4 emission in clay based and peat land based Melaleuca forest areas were 106 mg.m-2.h-1 and 135 mg.m-2.h-1, respectively. The CH4 emission was not correlated with either water and soil physical and chemical characteristics or water depth, but might be correlated microbial factors. We need to study water, soil characteristics, CH4 emission of months in years.
PURIFICATION AND CHARACTERIZATION OF LACCASE INVOLVED IN THE DECOLOURIZATION OF SYNTHETIC DYES AND 2,3,7,8-TCDD CONGENER DEGRADATION BY THE WHITE ROT FUNGUS ISOLATED FROM BAVI FOREST OF VIETNAM
Authors: Huy Chu Phung Khac
Published: April 2018

The fungal strain FBV40 was isolated from soil containing decayed wood in Ba Vi National Forest and capable of producing an extracellular laccase in the TSH1 medium. Two isozyme such as Lac1 and Lac2 were purified were estimated to be 55 and 60 kDa by SDS-PAGE. The optimum pH and temperature for the enzymatic activity of Lac1 were 3.0 and 60°C with ABTS using as the substrate. Kinetic constants Km and Vmax of Lac 1 were 0.3 µM and 200,000 µM/mins with ABTS as substrate. Cl-, SDS, and EDTA at any concentration (2 mM; 5 mM and 10 mM) strongly inhibited the activity of laccase. The enzyme was stable in the presence of several metal ions including Ni2+ (1 mM), Cu2+ (1 mM and 3 mM), Ca2+ (3 mM and 4 mM); in the presence of Cu2+ (2 mM) and Ca2+ (0.5 mM, 1.0 mM and 2.0 mM), laccase even showed the increase in the activity. The presence of metal ions Mn2+, Mg2+, Fe2+ completely inhibited the enzymatic activity at any examined concentration. The crude enzyme, as well as Lac 1, was able to decolourization MN.FBN dye from the textile industry from Ministry of Defence. This strain was able to degrade 2,3,7,8-TCDD isotop with initial concentration 2,000 ng-TEQ/L at rates over 46.8 % after ten days cultivation in the TSH1 medium. In the presence of three strains FBV40, FBVLa1 and FBD154 with the ratio 1:1:1, the degradation of this congener was achieved more than 95 % at the same time cultivation.
APPLICATION OF THE MODIFIED EBB TO IMPROVE LAKE WATER QUALITY IN HA NOI
Authors: Luong Hoang
Published: April 2018

The modified Eco-Bio-Block (EBB) has been studied and manufactured in Viet Nam, based on the process of blending friendly environmental materials as activated carbon, zeolite, kazemzite, sand and useful microorganisms. After culturing, bacterial communities in the modified EBB became significant abundant by DGGE analysis of 16S rDNA. The amount of microorganisms in the modified EBB was 107 CFU/g bacteria communities (Prokaryote). After 2 months treatment with the modified EBB, the quality of Khuong Thuong lake water has been significantly improved; the concentration of COD, NH4+, Coliform and Chlorophyll-a are reduced by 65.51 %, 64.28 %, 50 % and 68.42 %, respectively at the location A1. Sensuously, the lake water became brighter and cleaner. The application of the modified EBB to improve the lake water quality was conducted appropriately to the conditions at Vietnam in general and at Hanoi in particular. This research aims at localizing technology and improving efficiency on pond/lake water treatment. Further goal of the modified EBB application is to reduce pollutants in domestic wastewater form residential areas, in ditches, creeks and small lakes in Viet Nam.
APPLICATION OF ELECTRO-COAGULATION FOR TREATMENT OF WASTEWATER FROM PACKAGE PRINTING PROCESS
Authors: Thuy Nguyen Thi
Published: April 2018

Printing wastewater is generally considered as hazardous waste whose treatment and disposal are strictly regulated. Although electro-coagulation (EC) process has been successfully applied for the treatment of different types of wastewater, its application for printing wastewater is rarely reported. In this study, EC was applied to treat the printing ink wastewater, taken from a paper packing factory in An Giang Plant Protection Join Stock Company, which was highly colored and contaminated with organic compounds. The treatment process was performed using aluminum electrodes for two hours. Effects of applied voltage (5 - 40 V), pH (5 - 9), electrodes distance (1 - 5 cm), salt concentration in electrolyte solution (0.05 - 0.4 g/L), and the rotational speed of stirring (0 - 400 rpm) on the removal efficiencies of color and COD were investigated. Based on the effects of various factors, optimum condition for the treatment was given. Results showed that the EC process can effectively remove color and COD for 30 min. The effluent quality in terms of color and COD met well National Technical Regulation on Industrial Wastewater (QCVN 40-2011/BTNMT, column B). Finally, a comparison in removal efficiencies between the processes of EC and chemical-coagulation was also presented.
FACTORS THAT AFFECT THE REMOVAL OF NITROGEN AND PHOSPHOROUS FROM PIGGERY WASTEWATER USING MICROALGAE –BACTERIA CONSORTIUM
Authors: Chien Ngo Van
Published: April 2018

Currently, most piggery farms in Viet Nam use  biogas tank as a primary wastewater treatment system. However, even after the anaerobic treatment process, the concentration of nutrients was still high and exceeded the national effluent standard. If the wastewater was directly discharged into the water bodies, it was certainly hazardous to the environment and causes eutrophication. To remove the residual nutrients, several processes have been used, mostly chemical processes. The disadvantages of those chemical processes are high cost and the increase in amount of sludge. In this study, the biological method using microalgae-bacteria consortium was applied for the removal of nitrogen and phosphorous from wastewater from biogas treatment process. This study focused on factors which affect nitrogen and phosphorous removal efficiency in a batch reactor using microalgae-bacterial consortium. Studying on Chlorella sp A8. Activated sludge co-cultivation at different ratio (Chl/AS) gave good results in hydraulic retention time of 20 to 24 hours when C/N in wastewater was 4/1(m/m). In the fully mixing condition, DO range from 0.3 - 0.5 mg O2/L, the highest removal efficiencies of COD was 71 - 76 %;  NH4+-N was 40 - 47 %  and PO43--P was 64 - 77 % at Chl /As was 1.5:1, 2.5:1 and 1:1( g/g).
SYNTHESIS OF HYDROTALCITE POWDER AND BEAD TO REMOVE ARSENATE
Authors: Thanh Tung Nguyen
Published: April 2018

The affecting factors on the synthesis of hydrotalcite (HT) powder and bead for effective arsenate removal were investigated. HTs with a ratio of Mg:Al = 2:1 (MA) were synthesized by the co-precipitation method at 70 oC with reaction times of 1 and 120 -  300 min. The synthesis of MA with a reaction time of 1 min was done under high supersaturation condition, the others under low supersaturation conditions. The characteristics of MA were examined by X-ray diffraction (XRD), scanning electron microscopy, and nitrogen adsorption/desorption isotherms. According to the XRD patterns, pure HT was obtained for all tested conditions. With increasing reaction time from 1 to 300 min, the crystal size of MA increased from 4.9 to 11.3 μm, the surface area of MA increased from 9.3 to 71.4 m2/g. Batch-mode experiments showed that 1-min reaction time MA had the highest As(V) removal capacity. MA beads were separately synthesized using alginate and poly acrylamide (PAM) as binding agents. For alginate/MA, heat drying (110 oC) and freeze drying were applied to test the effect of these drying methods on the beads. The results showed that As(V) adsorption capacity of PAM/MA was the highest, closely followed by freeze drying/alginate/MA, much higher than that of heat drying/alginate/MA bead.
EFFECT OF FLUX CONDITION ON POLLUTANTS REMOVAL OF SPONGE MEMBRANE BIOREACTOR TREATING HOSPITAL WASTEWATER
Authors: Trong Dang Bao
Published: April 2018

Nowadays, membrane bioreactor (MBR) is an advanced available technology for wastewater treatment due to technical innovations and cost reduction. Especially, the high biomass concentration and long sludge retention time are favourable for the biodegradation of organic pollutants and nitrification. This research aims to study on the treatment performance of two lab-scale submerged membrane bioreactors treating hospital wastewater. One was operated at low fluxes (2, 4, 6 LMH) and the other at higher fluxes (10, 15, 20 LMH). Polyester-urethane cube sponge media (20 % v/v) was added into both reactors for fouling control and simultaneous nitrification denitrification (SND). The results showed that organic removal efficiencies were improved with an increase in flux. The removal efficiencies of COD and total nitrogen were 85-89 % and 26-42 % at low fluxes and 96-97 %, 53-65 % at higher fluxes, respectively. The treated water quality complied with Vietnam National Technical Regulation on health care wastewater, class A.
FABRICATION OF CELLULOSE-BASED CHITOSAN COATING ADSORBENTS FOR CAPTURE TO CADMIUM (II) AND ZINC (II)
Authors: Cam Trang Truong Thi
Published: April 2018

Cellulose fiberous adsorbent (CCCF) was prepared from sugacane agasse by coating chitosan  on the fiber surface. The chitosan layer coated on the cellulose fiber enhanced adsorption to Cd2+ and Zinc2+. High efficency of the CCCF of removal % for the Cd (II) and Zn (II) was  with  93.7 % and 93.0 %, respectively and the adsorption capacity was 2.0 mg/g.
STUDY OF SOME PARAMETERS RESPONSIBLE FOR GLYPHOSATE HERBICIDE MINERALIZATION BY ELECTRO - FENTON PROCESS
Authors: Le Thanh Son
Published: April 2018

Glyphosate (C3H8NO3P) is a highly effective broad-spectrum, post-emergence, non- selective organophosphate herbicide and commonly applied in Viet Nam. The removal of glyphosate in aqueous solution has been investigated by electro - fenton process which is based on the continuous production of ●OH radicals by reaction between Fe2+ catalyst and H2O2 electrochemical generated on cathode. The carbon felt (60 cm2) and Pt gauze (45 cm2) were used as cathode and anode of the electro-fenton system, successively. Monitoring the total organic carbon (TOC) during the electrolysis proved that pH, current intensity, electrolysis time and catalyst concentration influenced the glyphosate mineralization efficiency. At the optimal conditions: [Fe2+] = 0.1 mM; pH = 3; [Na2SO4] = 0.05M ;  I = 0.5A and the compressed air was bubbled through the solutions, the experiment results showed that 84.4 % Glyphosate was mineralized to CO2, H2O and inorganic acid after 50 min.
RESEARCH ON ION EXCHANGE CAPACITY OF OXIDIZEDACTIVATED CARBON
Authors: Hai Thinh Pham Thi
Published: April 2018

Ion exchange capacity of oxidized activated carbon (OAC) by HNO3 and surface treatment by NaOH solution was investigated. The HNO3oxidizedfunctional groups on the activated carbon surface, such as ketone, carboxylic acid and its derivatives, to maximum oxidation state. The OAC surface played the role as cation exchanger for adsorption of inorganic compounds, especially metallic cations. The adsorption capacity of OAC was investigated in batch mode with three representative ions with different valence from +1 to +3 (NH4+, Ca2+, Cr3+). The adsorption process was demonstrated by Langmuir and Freundlich isothermal model, and the maximum adsorption capacity according to Langmuir isothrermal equation was 20.4 mg/g for NH4+, 43.5 mg/g for Ca2+ and 38.5 mg/g for Cr3+. The results showed the OAC modified by HNO3 and surface treatment by NaOH solution improved adsorption capacity of AC for cations in solution to a higher level.
STUDY ON PRE-TREATMENT OF THE PHENOL, COD, COLOR IN THE COKE WASTEWATER BY OZONATION PROCESS
Authors: Thao Nguyen Thanh
Published: April 2018

This paper aims to study destroying process of phenol, COD, color in coke wastewater by ozone process. All experiments were conducted in the bath type reactor on phenol solution prepared in lab. The results showed that removal efficiency of the phenol, color and COD were high relatively. Experiments were realized in the different conditions: phenol concentration: 260; 500 and 720 mg/L; COD corresponding 610; 1200 and 1700 mg/L; inlet ozone concentration from 1.1 to 1.7 g/L.h to study the effect of pH, rotary of magnetic and phenol concentration. The main results showed that phenol removal efficiency was of  98 %; COD of 75 % after 22 minutes of reaction at ozone dose 1.7g/L.h for initial phenol 260 mg/L. Ozone treatment has highest treatment efficiency with phenol but reduction rate of COD was much slower than phenol.
PHOTOCATALYTIC DEGRADATION OF PARAQUAT USING N-TiO2/SiO2 UNDER VISIBLE LIGHT
Authors: Phuong Mai Nguyen Thi
Published: April 2018

In the present paper, photocatalytic degradation of paraquat using N-TiO2/SiO2 with different molar ratio of titanium: nitrogen (Ti:N) under visible light was investigated. The catalyst was prepared via immersed SiO2 in N-TiO2. N-TiO2 was synthesized by sol-gel method.  The N-TiO2/SiO2 catalyst was characterized using X-ray diffraction, UV diffuse reflectance spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy. The results from characterizations indicated that N-doped anatase TiO2 had a 20-25 nm size. Degradation of paraquat, at an initial concentration of 10 mg/L was determined by UV-Vis. Chemical oxygen demand (COD) was used for process performance. Based on the COD tests, the COD values in residual paraquat was lower than that in initial paraquat concentration after 8 hours illumination of visible light. Moreover, the experiment’s results indicated that 80% of paraquat was degraded within 8 h of illumination time. These results showed that N-TiO2/SiO2 with molar Ti:N=2:1 gives the highest degradation efficiency of paraquat under visible light. This catalyst was stable and reusable suggesting it can be applied to treat organic pollutant in water.
ADVANCED WASTEWATER TREATMENT BY HYDRAULIC AUTOMATIC FLOATING MEDIA FILTER
Authors: Son Tran Thanh
Published: April 2018

A pilot scale experiment was carried out in tertiary wastewater treatment using hydraulic automatic floating filter. The hydraulic automatic floating media filter has been working with 120 cm depth of polystyrene bed. Wastewater from secondary biological treatment of WWTP was treated  in the pilot filter with filtration velocity  of 4 m/h. Oxygen concentration was remained constantly at level 2.0 mg/l by using an ejector.  Headloss development and evaluation of SS, COD, NH4+ removals during filtration were objectives of the study. The experiment results showed that concentrations of SS, COD and NH4+ in effluent wastewater were kept lower than 5 mg/l, 30 and 0.5 mg/l respectively for almost filtration cycle. Effects of treatment in SS, COD and NH4+ were 88.27 %, 68.54 % and 5.59 %, respectively.
A data-driven framework for remaining useful life estimation
Authors: Nguyen Hoa Dinh
Published: April 2018

Remaining useful life (RUL) estimation is one of the most common tasks in the field of prognostics and structural health management. The aim of this research is to estimate the remaining useful life of an unspecified complex system using some data-driven approaches. The approaches are suitable for problems in which a data library of complete runs of a system is available. Given a non-complete  run of the system, the RUL can be predicted  using these approaches. Three main RUL prediction algorithms, which cover centralized data processing, decentralize data processing, and  in-between, are introduced and evaluated using the data of PHM’08 Challenge Problem. The methods involve the use of some other data processing techniques including wavelets denoise and similarity search. Experiment results show that all of the approaches  are effective in performing RUL prediction.
ANALYTICAL SOLUTIONS FOR BENDING, BUCKLING AND VIBRATION ANALYSIS OF FUNCTIONALLY GRADED CYLINDRICAL PANEL
Authors: Huan Duong Thanh , Tu Tran Minh , Quoc Tran Huu
Published: April 2018

The main purpose of this article is to present analytical solutions for bending, buckling and vibration analysis of cylindrical panel, which are composed of functionally graded materials (FGMs). Equations of motion are derived using Hamilton’s principle. The first-order shear deformation theory is used for developing Navier’s solutions of simply supported cylindrical panel. Comparison studies are presented to verify the validity of present solution. It is found that the presented results are close to those existing. The effect of volume fraction distributions, panel aspect ratio, and side-to-thickness ratio on the deflections, buckling loads and natural frequencies is also investigated.
THE TRANSFER MATRIX METHOD FOR MODAL ANALYSIS OF CRACKED MULTISTEP BEAM
Authors: Khiem Nguyen Tien , An Ninh Vu Thi , Hai Tran Thanh
Published: April 2018

The present study addresses the modal analysis of multistep beam with arbitrary number of cracks by using the transfer matrix method and modal testing technique. First, there is conducted general solution of free vibration problem for uniform beam element with arbitrary number of cracks that allows one to simplify the transfer matrix for cracked multistep beam. The transferring beam state needs to undertake only at the steps of beam but not through crack positions. Such simplified the transfer matrix method makes straightforward to investigate effect of cracks mutually with cross-section step in beam on natural frequencies. It is revealed that step-down and step-up in beam could modify notably sensitivity of natural frequencies to crack so that the analysis provides useful indication for crack detection in multistep beam. The proposed theory was validated by an experimental case study
NUMERICAL SIMULATION OF THE BULK FORMING PROCESS TO MANUFACTURE COUPLING DETAILS FROM TUBE BILLET
Authors: Phan Linh Thi Ha , Nguyen Trung Dac
Published: April 2018

Currently, most coupling details in the actuators are made by traditional methods such as bulk forming from block billet and then metal cutting. Such manufacturing methods often lead to material wastes due to cutting a large amount of excess processing. To save material and improve production efficiency, tube billet would be selected for bulk forming. However, when tube billet is used for bulk forming, it should be carefully calculated to avoid instability and folding defects in workpiece. This article presents the research on the forming process of the coupling details using numerical simulation and based on the obtained results, the suitable geometric size of tube billet for the forming operation in closed die can be determined.
A METHOD OF REAL-TIME NURBS INTERPOLATION WITH CONFINED CHORD ERROR FOR CNC SYSTEMS
Authors: Nguyen Quang Huu , Banh Long Tien
Published: April 2018

This paper presents a method of real-time CNC interpolation for free-form NURBS curves. The interpolation algorithm is based on second order Taylor’s expansion with the principle part being a formula for updating the parametric value u after each sampling period. With the updated value of u, a new interpolated point is calculated based on the DeBoor’s algorithm. In this paper, an efficient method of limiting chord error introduced by the interpolation algorithm is also presented with the basic idea of reducing machining feedrate at positions with a radius of curvature smaller than a critical value.
EFFECT OF DIFFERENT GUM TYPES ON STABILITY OF ANTIOXIDANT COMPONENTS AND PHYSICAL PROPERTIES OF SPRAY DRIED POUZOLZIA ZEYLANICA POWDER
Authors: Tan Nguyen Duy
Published: April 2018

The objective of this study was to investigate effect of blending three types of different gum (arabic, carrageenan and xanthan) in Pouzolzia zeylanica extract together with maltodextrin as well as encapsulated material during spray-drying process on the stability of antioxidant components (anthocyanin, flavonoid, polyphenol, tannin and antioxidant activities through DPPH radical scavenging capacity, ferrous reducing/antioxidant power FRAP and antioxidant ability index AAI); and physical properties (moisture content, water activity, particle size and morphology as well as the color, nonenzymatic browning) of products. The results showed that the sample which was blended with arabic gum and maltodextrin maintained well bioactive compounds and obtained powder had better quality characteristics than others. In this optimal sample, the content of anthocyanin, flavonoid, polyphenol and tannin were determined as 7.56 ± 0.106 mgCE/100 g, 31.15 ± 1.035 mgQE/g, 27.96 ± 0.380 mgGAE/g, 25.79 ± 0.530 mgTAE/g. The antioxidant activity through DPPH, FRAP and AAI were determined as 75.55 ± 0.65%, 102.87 ± 3.85 mM FeSO4/g and 38.17 ± 11.24. The moisture content, water activity, particle size, the color value of (L, a, b), total color difference (DE) and non enzyme browning (NEB) were determined as 6.42 ± 0.085 %, 0.5142 ± 0.0076, 6.26 ± 0.110 µm, 78.43 ± 0.189, 7.55 ± 0.065, 6.96 ± 0.180, 18.85 ± 0.580 and 0.298 ± 0.015, respectively.
EVALUATION OF THE INFLUENCE OF A VARYING MOLAR RATIO OF SODIUM DODECYL SULFATE TO WHEY PROTEIN ISOLATE ON THE STABILITY OF THE WHEY PROTEIN EMULSIONS
Authors: Thu Tran Le
Published: April 2018

In combination with the Lumifuge centrifugation and Zeta potential apparatuses, the influence of a varying molar ratio of Sodium Dodecyl Sulfate (SDS) to Whey Protein Isolate (WPI) on the stability of the whey protein emulsions at pH 4 and pH 5.5 is observed. Two whey protein stabilized emulsions were prepared by homogenizing 20 wt. % soybean oil and 80 wt. % whey protein solutions (0.5 wt.% whey protein in buffer, pH 4 and pH 5.5) at room temperature.By observation, the droplets are weakly flocculated at a ratio of SDS to whey protein of 256. This shows that there is a strong electrostatic repulsion between the emulsion droplets if much surfactant is adsorbed to the protein molecules, which prevents them from aggregating. The magnitude of the measured zeta potentials explained the stability of the emulsion at pH 4 as well as the emulsion at pH 5.5 is ensured at SDS to whey protein ratio equal to 256. The results of the transmission profile by Lumifuge separation analyzer at different time and at 3000 rpm (1200 g) elucidated that the stability of the whey protein emulsion at pH 4 and 5.5 is obtained upon dilution with SDS-WPI ratio of 256.
EVALUATION OF ANTIOXIDANT AND ANTI-AGING EFFICACIES OF COFFEA ROBUSTA EXTRACT ON HUMAN FIBROBLAST
Authors: Ngoc Hoi Nguyen Thi
Published: April 2018

The extract of Coffea robusta was evaluated via the antioxidant and anti-aging efficacies on human dermal fibroblast. Coffea robusta green beans harvested in Buon Ma Thuot - Vietnam were roasted and extracted by hot water. The anti-oxidant activity of the extract was measured by the DHHP assay. Additionally, the extract was dosed to fibroblast and proteome analysis using 2-D was conducted to observe the changes of proteins involving in aging process. The results show that the extract is a strong anti-oxidant factor with low IC50 value for DPPH scavenging (33.2 mg/L), and significant up-regulation of 5 natural antioxidant enzymes (GPX2, GCLM, PRDX4, GSTA1 and NQO1), as well as down-regulation of 2 supporting-free-radicals proteins (NF-kB1 and TNF-alpha) of human fibroblast.  Furthermore, the extract is a potential anti-aging factor with the down-regulation of 4 proteins related to the degradation of elastin and dermal extracellular matrix (CELA2B, CELA3A, CELA3B and MMP3).
EFFECT OF TEMPERATURE, WATER ACTIVITY AND CINNAMON ESSENTIAL OIL ON THE GROWTH OF ASPERGILLUS FLAVUS LA01 AND ASPERGILLUS NIGER LA04
Authors: Kim Lien Phan Thi
Published: April 2018

The aim of the study was to evaluate the influence of temperature, water activity and cinnamon essential oil on the growth of Aspergillus flavus LA01 and Aspergillus niger LA04 and these factors were further optimized to inhibit their growth. Both strains were isolated by Potato Dextrose Agar medium (PDA) and identified by sequencing method from rice collected in Long An province. Evaluating these factors’ inhibition on the fungi growth was based on growth rate at the various points of water activity (aw) (v/v) such as 0.85, 0.90, 0.95, 0.99 and at 25 oC, 30 oC, 37 oC, 42 oC; at various concentrations of the oils 0 %, 1 %, 3 %, 5 %, 7.5 %, 10 % and 15 % at  30 oC incubated for 5 days - the disc diffusion method. The results showed that             30 oC and aw = 0.95 - 0.99 were optimum conditions for Aspergillus flavus LA01 and Aspergillus niger LA04 growth. However, at 42 oC, 37 oC and aw = 0.85 - 0.9 could control Aspergillus flavus LA01 and Aspergillus niger LA04 growth. At concentration of 10 - 15% cinnamon essential oils (EOs), 30 oC and aw = 0.9 - 0.95 could also inhibit them.