bluuebunny/crossref_metadata_2025 huggingface dataset:
COMBINED STEAM AND CO2 REFORMING OF CH4 OVER NICKEL CATALYSTS BASED ON Al2O3–MO (M= Mg, Ca, Ba)
Authors: H. Phuong P.
Published: April 2018

A series of 10 wt% Ni/Al2O3–MO (M = Mg, Ca, Ba) catalyst was prepared by impregnation method for applying in the combined steam and carbon dioxide reforming of methane (CSCRM). In this study, five supported nickel catalysts were impregnated on different supports. All of the supports have been obtained by co–precipitation method and also have been investigated. Several techniques, including N2 physisorption measurements, X–ray powder diffraction (XRD), temperature–programmed reduction using H2 (H2–TPR), and transmission electron microscopy (TEM) were used to investigate catalysts’ physicochemical properties. The results showed that MgO was the most suitable promoter comparing with CaO and BaO in CSCRM. The presence of MgO in Ni/Al2O3 changed catalysts’ characteristics leading to an increase in the catalytic activity and stability with time on stream (TOS). It was found that the suitable catalyst was Ni–based on Al2O3–MgO of mass ratio 2:1 which showed a high metal dispersion as well as dominated spinel structure. The CH4 and CO2 conversion at 800 °C reached 99.8 % and 51.7 %, respectively. Catalytic stability of this catalyst with TOS at 800 °C could reach to more than 20 hours until it started decreasing.
APPLICATION OF SELF–CLEANING TREATMENT ON COTTON AND PES/CO FABRIC USING TiO2 AND SiO2 COATING SYNTHESIZED BY SOL–GEL METHOD
Authors: Huong Bui Mai
Published: April 2018

The photocatalytic activity of TiO2–SiO2 coated and TiO2 coated on 100% cotton and PES/Co fabrics was investigated through the self–cleaning of red wine stains and coffee stains. It was shown that a TiO2 species could be produced at temperatures of 25 °C, 40 °C and 60 °C with acceptable photo–activity and TiO2–SiO2 nanocomposites were prepared by a sol–gel process at a low temperature. The discoloration of red wine and coffee led to CO2 evolution that was more efficient for TiO2–SiO2 coated cotton for samples than of TiO2 coated ones. The textile surface did not show any change after several consecutive light–induced discoloration cycles of a red wine stain and coffee stain. The structural properties of these nanocomposites were characterized with scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT–IR). The scanning electron microscope (SEM) photo showed that the TiO2–SiO2 layer is thicker than TiO2 layer on the cotton fabric and PES/Co fabric and the Ti–particles were always surrounded by amorphous SiO2 and never alone by themselves. The TiO2–SiO2 nanocomposites were coated onto cotton and PES/Co fabrics by a simple dip–pad–dry–cure process.
SYNTHESIS OF AN AZIDE–THIOL LINKER FOR HETEROGENEOUS POLYMER FUNCTIONALIZATION VIA THE “CLICK” REACTION
Authors: Truong Thuy Thu
Published: April 2018

In this study, the synthesis of a telechelic linker bearing both azide and thiol functional groups was described. The reaction conditions were investigated to optimize the reaction yield. The product was analyzed using thin layer chromatography (TLC) and proton nuclear magnetic resonance (1H NMR). The employment of the obtained azide–thiol linker in heterogeneous polymer “click” functionalization was demonstrated for the first time, which was monitored by an online FT–IR method. The obtained telechelic azide–thiol linker is envisioned to be useful chemical tools to link macromolecular chains via orthogonal click reactions.
SYNTHESIS AND CHARACTERIZATION OF MONOFUNCTIONAL BENZOXAZINE FROM CARDANOL
Authors: Viet Cao Xuan
Published: April 2018

A novel thermoplastic polybenzoxazine was synthesized based on agrochemical renewable cardanol–a by–product of cashew nut shell liquid (CNSL). A solventless synthesis of monofunctional benzoxazine monomer based on cardanol, aniline and paraformaldehyde was carried out. The liquid benzoxazine monomer was characterized by 1HNMR and FTIR spectroscopy. Curing characteristics at different temperatures were studied and monitored by differential scanning calorimeter (DSC). The appearance of two exothermic peaks associated with reaction of double bonds of the aliphatic side–chain and ring opening polymerization of benzoxazine. High thermal stability of the polymer sample was confirmed by thermogravimetric analysis (TGA).
EFFECT OF POLY(METHYL METHACRYLATE) MOLECULAR WEIGHT ON ITS TERNARY POLYMER BLENDS MICRO–STRUCTURE USING X–RAY COMPUTED TOMOGRAPHY
Authors: Nguyen Hoa T.
Published: April 2018

A high–contrast X–ray computed tomography (XCT) applied to the ternary polymer blends of poly(methyl methacrylate) (PMMA), polypropylene (PP) and polyamide 12 (PA12), we investigated micro–structure three–dimensional (3D) images of blends with gradually increasing of molecular weight (Mw) of PMMA. The 1:1:1 mixture of PMMA/PP/PA12 were prepared by mixing on an internal mixer at 200 °C, then annealing at 200 °C under compressor of 5 MPa in order to restore the crystalline structure of polymer blends. After that, blends were compressed molding and cooled by water. Finally, they were stored in the vacuum oven at the same annealing temperature before taking XCT and then rendering to 3D images. Changing various methods of annealing time, we could observe vary 3D internal structure clearly of these blends. We also conclude the effect between Mw of PMMA and the morphologies of these ternary polymer blends.
EFFECTS OF Nd2O3 ON THE CRYSTALLIZATION AND PROPERTIES OF GLASS CERAMIC IN Li2O–K2O–Al2O3–SiO2–P2O5 SYSTEM
Authors: H. Minh N.
Published: April 2018

Glass ceramics (GCs), which often contain a small amount of rare earth oxides to improve their performance, are ideal for dental restorative applications. The aim of this study was to investigate the various effects of Nd2O3 content (0–1 wt%) on crystallization and properties of GC derived from Li2O–K2O–Al2O3–SiO2–P2O5 system. The glass blocks were formed from the molten at 1450 °C. Based on the DTA results, the glass samples were experienced by two–stage heat–treatment (600 °C/ 90 min + 720 °C/ 30 min) to change to ingots. After that, the ingot samples were fired in a hot pressing furnace EP3000 at 930 °C for 30 min. The results of powder X–ray diffraction (XRD) indicated that the final GCs contained crystals such as lithium disilicate (Li2Si2O5 or LS2), lithium metasilicate (Li2SiO3 or LS) and the traces of lithium phosphate (Li3PO4). With increasing Nd2O3 content, the relative amount of LS phase increased slightly while LS2 phase decreased. However, the final GC containing 0.75 wt% Nd2O3 had the highest bending strength at 293 MPa, the lowest chemical solubility and relative high Vicker hardness. These samples had a high degree of crystallization and the highest relative content of desired LS2 phase.
APPLICATION OF TiO2–P25 IN THE PHOTODEGRADATION OF n–LAURYL DIETHANOLAMINE AND CINNAMIC ACID IN PRESENCE OF OXYGEN
Authors: C. Loc L.
Published: April 2018

In this paper, the activity of TiO2–P25 in the photodecomposition of recalcitrant organic compounds such as n–lauryl diethanolamine (n–LDA) and cinnamic acid (CA) solution in UV + BLED light in presence of oxygen was investigated and the optimum conditions of reaction were determined. With physicochemical characteristics such as anatase/rutile ratio of 80/20, the crystallite size of 23 nm, BET surface area of 43.6, the light absorption wavelength of 390 nm, band gap energy of 3.17 eV, and point of zero charge of 6.3, TiO2–P25 catalyst is able to photodecompose more than 95 % of LDA and CA after 90 minutes in presence of oxygen under irradiation of UV–B light.
ENHANCEMENT OF Li–ION BATTERY CAPACITY USING NICKEL DOPED LiFePO4 AS CATHODE MATERIAL
Authors: Hang La Thi
Published: April 2018

Selective supervalent cations (M = Ni, Mn, La etc.) doped LiFePO4 (LFP) is an effective route to enhance its electrical conductivity, thereby improving electrochemical performances of lithium–ion batteries. For this purpose, nickel doped LiFePO4 based cathode material was investigated at different substitution amounts (xNi = 0.05, 0.10). LiFe1–xNixPO4 (LFNP) was synthesized from Ni(NO3)2.6H2O, LiOH.H2O, FeSO4.7H2O, H3PO4, and ascorbic acid precursors via solvothermal technique, followed by calcination in nitrogen atmosphere at 550 °C for 5 h. The structure and morphology of synthesized materials were examined by X–ray diffraction, Scanning electronic microscopy and Raman vibrational micro–spectroscopy. The electrochemical performances of doped materials were studied in Swagelok–type cell using LiPF6/EC–DMC (1:1) as electrolyte. LiFe1–xNixPO4 was shown to exhibit homogenous particles size of 50 ¸ 150 nm. The doped materials were titrated to quantify iron and nickel contents in samples. As anticipated, the electrochemical performances of LiFe1–xNixPO4were significantly enhanced compared to those of undoped LiFePO4.
REMOVAL OF Cd(II) FROM AQUEOUS SOLUTIONS BY CRUMPLED GRAPHITE OXIDE
Authors: Son Ha Xuan
Published: April 2018

In this study, crumpled graphite oxides (CGOs) were fabricated from graphite electrode of exhausted dry batteries (RG) by cathodic plasma electrolysis method (CPE) and applied for removing Cd(II) from aqueous solutions. The effects of pH, contact time, and initial concentrations on the removal of Cd(II) ions were studied. A removal efficiency of ∼98 % was obtained after 120 min, via the dispersion of 15 mg of CGO in Cd(II) solutions (40 mL, 1 ppm) at pH 6. The maximum adsorption capacity (qmax) was calculated to be 40.82 mg/g. Results showed that CGO is an effective adsorbent for the removal of Cd(II) from aqueous environment and acts as a promising adsorbent for the removal of other heavy metals from the polluted water.
RESEARCH ON HARVESTING OF MICROALGAE CHLORELLA SP. BY ELECTROCHEMICAL FLOTATION METHOD USING CORROSIVE ELECTRODES
Authors: Hung Ha Vinh
Published: April 2018

Microalgae are a promising feedstock for biodiesel production. Harvesting of microalgal biomass is still a bottleneck to its commercial scale application, due to small cell size, low culture densities, colloidal stability and thus economic disadvantage. The aim of this study was to evaluate the biomass separation of the small size microalgae Chlorella sp. by electrochemical flotation process with rectangle electrodes using aluminum or iron plates. The most effective conditions for this experiment involved the use of an aluminum electrode for 30 min with a current density of 1.5 mA/cm2, whereas the iron electrode has been used ineffectively with the same of conditions. The effect of current density (0.5–3 mA/cm2), concentration of microalgae biomass (0.29–1.5 g/L), and electrolyte (0–2 g/L) for aluminum electrode were analyzed. The highest recovery efficiency of 90 % was obtained for Chlorella sp. at 1.5 mA/cm2 in 30 min and concentration of microalgae biomass of 0.74 - 1.5 g/L with power consumption of 1.36 kWh/kg.  The electrochemical flotation process with aluminum electrodes could be a possible harvesting step at commercial scale for microalgal biomass production.
BIO-METHANE POTENTIAL TEST FOR ANAEROBIC CO-DIGESTION OF FAECAL SLUDGE AND SEWAGE SLUDGE
Authors: Hoai An Vu Thi
Published: April 2018

Faecal sludge (FS) samples taken in Hanoi urban area had COD values ranging from 2.83 g/L to 83.83 g/L,TN values from 0.18 g/L to 3.95 g/L, and VS/TS ratio from 47.5 % to 87.7 %. Sewage sludge (SS) samples taken from sewage treatment plants in Hanoi had COD values ranging from 2.22 g/L to 24.97 g/L, TN from 0.16 g/L to 1.24 g/L, VS/TS ratio from 53.5 % to 69.5 %. Bio-methane potential (BMP) tests at mesophilic anaerobic condition (35 oC) provided results of methane production from FS, primary sewage sludge (PSS), waste activated sludge (WAS1 and WAS2) and mixture of primary and secondary sewage sludge at sludge thickener (WAS) as much as 242.3 NmL/gVS, 310.5 NmL/gVS, 294 NmL/gVS, 228.2 NmL/gVS and 282.3 NmL/gVS, respectively. Co-digestion of FS and WAS at different mixing ratios provided from 269.3 NmL to 294.8 NmL CH4 per gram of fed substrate VS. The values of methane yield have shown promising sludge-to-energy option with FS-SS co-digestion. FS-SS co-digestion in anaerobic digesters built at municipal sewage treatment plants which are often working under capacity provides chance to combat with FS and SS challenges, utilizing infrastructure facilities efficiently.
FRACTION AND DETERMINATION OF CAPSAICINOIDS FROM RED PEPPER FRUITS WITH INSECTICIDAL ACTIVITY AGAINST MEALWORM, Tenebrio molitor, AND SUPERWORM, Zophobas morio
Authors: Ngo Ngai Thi
Published: April 2018

Green chemistry has recently been an active area of research and it is expected to replace the chemical synthesis in agriculture. In this study, our attempt is to fractionate and determine the capsaicinoids from red pepper fruit to control mealworm Tenebrio molitor and superworm Zophobas morio. The methanol extraction of red pepper fruit (Capsicum annuum L.) effectively killed T. molitor and Z. morio at the concentration of 10000 ppm. The insecticidal activity of n-hexane, dichloromethane and aqueous layers derived from the extract by liquid-liquid partitioning were evaluated. Among them, only dichloromethane layer showed insecticidal activity; whereas n-hexane and aqueous layers were inactive against tested pests. The dichloromethane layer was successively fractionated by silica gel column chromatography to afford insecticidal compounds. The chemical structures of active compounds in dichloromethane layer were elucidated by the analysis of NMR and MS spectroscopic data. The active compounds were determined to be as capsaicinoids and their insecticidal activity was also evaluated using the in vitro residual contact bioassay method. The extracts containing capsaicinoids were formulated into a suspension concentrate (SC) biopesticide and evaluated for efficacy against T. molitor and Z. morio. The biopesticide caused mortalities by 95-100 % against tested pests at 1000 µg/mL. The study results suggested that extracts containing capsaicinoids could be used as active ingredients for the preparation of the biopesticide to control insect pests thereby preserving stored products in sustainable agriculture.
AEROSOL pH IN HO CHI MINH CITY, VIET NAM
Authors: Huy Duong Huu
Published: April 2018

Aerosol pH is an important parameter that affects air quality, and the health of aquatic and terrestrial ecosystems. However, the lack of such data was reported in Ho Chi Minh City (HCMC), Vietnam. In this study, we estimated the aerosol pH in fine particulate matter (PM2.5) collected in HCMC, Vietnam using the thermodynamic equilibrium models (E-AIM Extended Aerosol Inorganics Model and ISORROPIA-II), and the phase partitioning of ammonia. Aerosol pHs estimated by different methods were 1.7 – 2.9. Good correlations between the phase-partitioning approach and models in predicting the aerosol pH were observed with R2 from 0.77 to 0.89, suggesting that the assumption of equilibrium is valid at the HCMC site.
PRELIMINARY ASSESSMENT OF BTEX CONCENTRATIONS INDOOR AND OUTDOOR AIR IN RESIDENTIAL HOMES IN HANOI, VIETNAM
Authors: Le Ha Vo Thi
Published: April 2018

Indoor air quality is considered to be of great concern due to its adverse impact on the human health nowadays. BTEX concentrations in 29 residential homes including (new/renovated and  old) were studied in Hanoi Metropolis and influencing parameters such as smoke habit, cooking appliances, solvent consumption, and ventilation system were considered in this study. Samples were conducted using active diffusion monitors and analyzed by GC/FID. Concentrations of BTEX indoor and outdoor in new/innovated homes were significantly higher than those in old homes. Benzene was used as cancer risk maker, whereas toluene and xylene were used as non-cancer risk marker. Among BTEX compounds, xylene showed the most notable hazard quotient and was the main pollutants responsible for high risk for the toddlers. Benzene showed an upper-bound life time cancer risk that exceeds the US.EPA benmark, presenting moderate risk for the toddlers.
IDENTIFYING THE EUTROPHICATION STATUS OF SHALLOW WATERS BASED ON THE ESTIMATED TROPHIC STATE INDEX FROM SATELLITE DATA
Authors: Bac Nguyen Anh
Published: April 2018

Remote sensing techniques have been widely used to measure the qualitative parameters of waterbodies. This work identifies the eutrophication status of 6 small and shallow lakes, including Hoan Kiem, Ba Mau, Bay Mau, Dam Tri, Truc Bach and Hai Ba Trung, in the Hanoiurban area using an empirical model developed from the in situ trophic state index (TSI) and Landsat 8 satellite data acquired on 21 September 2016 and 10 December 2016. The strong correlation between TSI values and the reflectance ratio of Landsat 8 band 3 versus band 2 (R2 = 0.69) allowed the quantification of the TSI by an exponential function (MSE = 0.04). Validation of the model for other water samples collected on the dates shows a high accuracy (R2 = 0.85; MSE = 0.4). Maps of TSI over the 6 lakes on the two dates surveyed clarified the eutrophication status of these lakes in autumn 2016 and demonstrate the trend in identifying the distribution of TSI from space. Study methods and data stated in this study confirm the high applicability of Landsat 8 satellite data for monitoring shallow lake eutrophication status.
THE METHANE UPTAKE CAPACITY OF SOIL GARDEN
Authors: Ngo Phuong Linh
Published: April 2018

Aerobic CH4 oxidation through methanotrophic bacteria is the only terrestrial sink and the only sink that can be altered directly or indirectly by human so far. However, the capacity of this sink is highly variable in different ecosystems depending on four key factors which are soil diffusivity, soil temperature, soil nitrogen status and soil moisture. While many studies in Australia experience the significant inverse correlation between soil moisture and CH4 flux magnitude in temperate forests in Victoria and New South Wales, there is a lack of research about the methane uptake capacity of garden soil. Consequently, we hypothesise that there is a similar pattern of CH4 uptake by garden soil. The aim of this study is to determine the capacity of CH4 oxidation along the soil garden profile. Our study was conducted at a native garden in Burnley Campus of the University of Melbourne, Victoria, Australia. Our results show three main findings. Firstly, garden soil can become a significant sink of CH4. Secondly, there was a significant correlation between soil moisture and the soil CH4 uptake rates. Finally, there was an expansion of the CH4 oxidation layer to deeper soil layers as the soil dries at the surface.
HOUSEHOLDS’ WILLINGNESS TO PAY FOR SOLID WASTE MANAGEMENT SERVICES IN LOC NINH COMMUNE, DONG HOI CITY
Authors: Tuan Tran Ngoc
Published: April 2018

The willingness to pay (WTP) for environmental sanitation fee was examined with an aim to estimate the average WTP of local residents in Loc Ninh commune, Dong Hoi city, and to analyze a number of factors influencing the WTP level. Ninety six households were selected with a Stratified Random Sampling technique and interviewed with structured questionnaires on different fee levels that they were willing to pay for. The analysis results processed with Weighted Average Method showed that the average WTP was 18,440 VND/month. The highest and lowest WTP per month were 26,000÷29,000 VND/month and 17,000 VND/month, respectively. Based on Regression Analysis Model added in the Analysis Toolpak of MS. Excel, this paper investigated 4 key demographic characteristics of respondents; namely age, sex, occupation and per capita income which likely affected the WTP level. Of which, education and per capita income greatly influenced the WTP, i.e. respondents with higher levels of these factors showed higher level of WTP. In terms of occupation, the WTP of those residents who were engaged in farming were lower than that of other surveyed occupations.
CHARACTERISTICS OF HOUSEHOLD SOLID WASTE IN HUE CITY
Authors: Tuan Tran Ngoc
Published: April 2018

This paper examined the characteristics of household solid waste with a hope of contributing to the improvement of solid waste management in Hue city. The study was conducted by collecting, classifying and measuring household solid waste from 62 households in 7 consecutive days. A structure questionnaire was also used in the interviews with survey households to collect data on their demographic characteristics. The results show that the household solid waste was generated evenly on a daily basis with an amount of 286±171g/person/day during the weekdays. The composition of household domestic solid waste was divided into 17 different groups; of which, the two groups representing the largest amount were food waste (56.35 %) and garden waste (10.89 %). Hazardous waste accounted for a very small proportion (only 0.26 %). The detailed composition ratio of food, garden waste, nylon, paper, plastic, porcelain, etc. and mixed stuff were defined at 56.35 %, 10.89 %, 8.93 %, 3.22 %, 3.22 %, 3.02 %, etc. and 10,23 %, respectively.
PHOTOCATALYTIC DEGRADATION OF FORMIC ACID INAQUEOUS WITH Ni DOPED TiO2 COATED ON SILICAGEL
Authors: Thanh Hai Nguyen Thi
Published: April 2018

Formic acid (FA) photocatalytic degradation using nickel doped TiO2 (Ni-TiO2) coated on silica grain (Ni-TiO2/SiO2) by sol-gel method has been studied. Nickel with a different molar ratio as 0.2, 0.4, and 0.8 % mole was used in this study. Samples were characterized by XRD, SEM, and UV-vis spectroscopy. Conditions such as dark, ultraviolet-visible and visible light were performed to assess the photocatalytic ability of Ni-TiO2/SiO2. The results showed that, catalyst samples had uniform nanosize, anatase crystalline structure and the band-gap energy of Ni-TiO2/SiO2 was lower than that of TiO2/SiO2 sample. The highest photocatalyst activities were obtained at 0.2 % mol of Ni for both irradiations. The FA concentration was not changed in the dark condition. Under ultraviolet-visible irradiation, FA concentration decreased from 10-4 mM to 2.10-5, 7.10-5 and 9.10-5 mM with 0.2, 0.4 and 0.8 % mole of Ni, respectively. With visible light condition, FA concentration decreased from 10-4 mM to 7.10-5 mM when Ni dopant amount was 0.2 % mole. Change in FA concentration was negligible with 0.4 and 0.8 % mole of Ni dopant amount. It proved that the photocatalytic activity of Ni-TiO2/SiO2 under visible light irradiation was generated by doping a small amount of nickel into TiO2. However, under visible light irradiation with 420 nm filter, FA photodegradation of Ni/TiO2/SiO2 increases when Ni dopant content increases from 0 % mole to 0.8 % mole.
DEGRADATION OF GLYPHOSATE HERBICIDE BY AN ANODIC OXIDATION PROCESS
Authors: Le Thanh Son
Published: April 2018

Glyphosate is occasionally detected as water contaminants in agriculture areas where the herbicide is used extensively. The removal of glyphosate in synthetic solution using advanced oxidation process (AOP) is a possible approach for remediation of contaminated waters. Here, the ability of anodic oxidation for the degradation and mineralisation of glyphosate herbicide was investigated using Ti/PbO2 anode in batch mode. The experimental results provided that the current intensity, treatment time, pH and initial concentration are the influent parameters on the glyphosate degradation. At the optimal condition, 16.9 mgL−1 of glyphosate decreased up to 0.6 mg L−1, i.e the removal efficiencies were 95 ± 16 %. This work demonstrates that electrochemical oxidation is a promising process for degradation and mineralization of glyphosate.
APPLICATION OF NITROSOMONAS AND ANAMMOX COMBINATION IN A REACTOR FOR AMMONIUM REMOVAL IN SWINE WASTEWATER
Authors: Dien Dang Van
Published: April 2018

This study investigated the combination of two kinds of autotrophic bacteria, named Anammox and Nitrosomonas in a reactor to remove ammonium existed in swine wastewater. The reactor which was operated with swine wastewater taken from Dong A pig breeding enterprise (Di An, Binh Duong) had 15 liters volume. The biomass carrier used in this model was made from the synthetic acrylic with attached capacity of 0.5-0.6g-SS/g-material. The sludge was taken from a reactor using partial nitritation/Anammox processes of a previous study at Vietnam Academy of Science and Technology. In 118 days of operation, average influent ammonium was 350mg/l, feeding to three loading rates (LR) 0.47, 0.70, 0.93 kg N-NH4+/m3/day with flow rate 20, 30, 40 liters, respectively. The highest efficiency was found at the first loading rate 0.47 kg N-NH4+/m3/day with 91.55 %. The other loading rates 0.70 and 0.93 kg N-NH4+/m3/day gave lower efficiency, 78.08 and 70.5 %, respectively. VSS at the beginning and the end of the operation were 4g/l and 9.4 g/l, respectively. The optimum pH for the reactor was in range of 7.8 - 8.0.
ESTIMATION OF BIODEGRADABLE MATERIAL CONCENTRATIONS IN THE SEWAGE USING IWA ACTIVATED SLUDGE MODEL
Authors: Nguyen Duong Chanh Quang
Published: April 2018

Conventional water analysis based on influent sampling holds a limitation of accuracy due to fluctuation of influent composition in time. The study was aimed at identification of the composition from a back-calculation of biological responses in the activated sludge reactor. The developed approach was based on IWA ASM1, which was structured by the influent constituents. A pilot-scale activated sludge 2 reactors (with and without primary settler were installed and operated continuously at Doan Thi Diem Str., Hue, Vietnam. Focusing on the activated sludge sampled from the reactor with a settler, the soluble biodegradable organic concentration in the influent was calculated. From the state variables in the activated sludge reactor, the organic matter and nitrogen compounds in the influent were calculated.
WATER QUALITY CLASSIFICATION BY ARTIFICIAL NEURAL NETWORK - A CASE STUDY OF DONG NAI RIVER, VIETNAM
Authors: Than Nguyen Hien
Published: April 2018

The Dong Nai River is the main source of supplied water for Ho Chi Minh City, Dong Nai, Binh Duong province and other areas. However, the water quality state of the Dong Nai River has been heavily pressured by discharged sources from urban areas, industrial zones, agricultural, domestic activities, etc. In this paper, the authors employed the artificial neural network model (ANNs) to classify water quality of Dong Nai River that apply a new tool to assess water quality in Vietnam. The monitoring data were used for eight years from 2007 to 2014 with 23 monitoring stations. Two neural network models including a multi-layer perceptron (MLPNN) and a generalized regression network (GRNN) were employed to classify water quality of the Dong Nai River. The results of the study showed that GRNN and MLPNN classified excellently water quality. Optimal structure of the MLPNN was H8I4O1 with model error about 0.1268 while the GRNN was error about 0.00001615. Comparing the result of water quality classification between the ANNs and the fuzzy comprehensive evaluation indicated that they were in close agreement with the respective values (the accurate rate of GRNN 100% and 98,5 % of MLPNN).
PHOTODEGRADATION OF NON-BIODEGRADABLE ORGANIC COMPOUNDS IN LANDFILL LEACHATE BY Mn-TiO2-BENTONITE
Authors: Duc Tran Minh
Published: April 2018

The photocatalytic process helps to enhance biodegradability of landfill leachate. TiO2-bentonite nanocrystalline powders with various Mn-doping levels were synthesized by the sol–gel process using TiCl4 and manganese nitrate as precursors. The synthesized nanomaterials were characterized by X-ray diffraction analysis (XRD), Scanning electron microscopy (SEM) and Energy dispersive X-ray analysis (EDX). The experimental results indicated that the removal of chemical oxygen demand (COD), biological oxygen demand (BOD5), total organic carbon (TOC) and color by 2%Mn-TiO2-bentonite photocatalyst could be reached more than 81%, 83%, 65% and 96%, respectively. Under optimal conditions, the BOD5/COD ratio was elevated from 0.08 to 0.40. The organic compounds in landfill leachate before and after treatment using Mn-TiO2-bentonite photocatalyst were analyzed by means of high performance liquid chromatography (HPLC). The analysis result of HPLC diagrams revealed phenol, p-nitrophenol, p-crezol and some kinds of organic pollutants in the landfill leachate were totally decomposed after 12 h of treatment. Moreover, the re-usability of Mn-TiO2-bentonite catalysts was also studied with good efficiency. It was concluded that the Mn-TiO2-bentonite photocatalyst could be a cost-effective method for the pre-treatment of non-biodegradable organic pollutants in the landfill leachate.
COMPARISON OF OXIDIZED CARBON NANOTUBES EFFICIENCIES FOR BENZENE AND TOLUENE REMOVAL FROM AQUEOUS SOLUTION
Authors: Quynh Anh Le Huu
Published: April 2018

Carbon nanotubes (CNTs) have been widely used as adsorbent in environmental treatment, especially for pollutants and volatile organic compounds (VOCs). The purpose of this work is to develop materials based on functionalized multiwalled carbon nanotubes (MWCNTs) for Benzene and Toluene removal. This will exploit adsorption propertiesof modified MWCNTS for Benzene and Toluene. In the first study, adsorption capacity of pristine MWCNTs to Benzene and Toluene in aqueous solution was investigated through isotherm study. The qe values of CNTs for Benzene and Toluene were 45,5 mg.g-1 and 56.3 mg.g-1, respectively and a contact time of 120 min. The modification of three oxidized MWCNTs were performed with acid solution (HNO3/H2SO4), hydrogen peroxide (H2O2) and sodium hypochlorite (NaOCl). The modified MWCNTs materials (CNT-COOH,CNT-NaOCl,CNT-H2O2) were characterized by Fouriertransform infrared spectroscopy (FT-IR). The effects of functional groups on the MWCNTs on the adsorption capacity of Benzene, Toluene in aqueous solution were studied and compared to pristine MWCNTs. The results demonstrated that the efficiency of adsorption was significantly enhanced with oxidized CNTs, and following the order CNTs-NaOCl > CNTs-H2O2> CNTs-H2SO4> pristine CNTs.
Contents
Authors: Contents Contents
Published: April 2018

50 bài báo
APPLICATION OF HEDGE ALGEBRAS FOR CONTROLLING MECHANISMS OF RELATIVE MANIPULATION
Authors: Khoi Phan Bui , Toan Nguyen Van
Published: April 2018

This paper presents a method for controlling mechanism of relative manipulation (MRM robot), that based on an algebraic approach to linguistic hedges in fuzzy logic. The proposed model of MRM robot is introduced as two component mechanisms, collaborating to realize technological manipulations. MRM robot has complex structure [1, [2]; therefore, robot system's  mathematical equations describing dynamical behaviors are complicated and voluminous [3,[4, 5]. Furthermore, the components affect MRM robot's dynamics that are difficult to determine adequately and exactly. Applying the well-known methods (based on dynamical equations) such as PD/PID, computed torque algorithm...for robot control is difficult, especially with MRM robot. By dint of the human-like inference mechanism, designing controller thanks to fuzzy logic can overcome the mentioned drawbacks [6]. However, the linguistic variables in fuzzy logic are not represented by any physical values; and hence, the comparison between the linguistic variables is unable. Moreover, composition of fuzzy relations, defuzzification use approximation function which can trigger error in data process. Hedge Algebras(HA) gives favorable conditions to restrict fuzzy logic's drawbacks because the linguistic labels in Hedge Algebras are represented by semantic values; and, composition of fuzzy relations and defuzzification are processed by simple interpolation and mapping functions. The obtained results from HA controller are compared to the obtained results from two methods which are presented in [6] (fuzzy controller and computed torque controller). Keywords: mechanism of relative manipulation (MRM robot), hedge algebras.
A HOPANE TRITERPENOID FROM THE MYCELIUM OF Isaria japonica IN VIETNAM
Authors: Tuan Nguyen Ngoc , Kim Anh Tran Thi , Kuo Ping-Chung , Thang Tran Dinh
Published: April 2018

A hopane triterpenoid (11b, 22-dihydroxyhopane) was isolated from the methanol extract of the mycelium of Isaria japonica in Vietnam. The structure of this compound was elucidated using a combination of 1D and 2D NMR techniques (1H-, 13C-NMR, COSY, HSQC and HMBC). In the study, we reported the comprehensive 1H- and 13C-NMR spectral data of 11b, 22-dihydroxyhopane for the first time.
A Systematic Approach to the Dilemma between Flood Vulnerability and Resilience - Review and Concepts
Authors: Hoang Tri Cong , Hens Luc , Pham Phuoc Minh Thien , Nguyen Hung Thanh , Tran Phuong Ha
Published: April 2018

The nature of "vulnerability" is that it not only exists when elements at risk are exposed to flood, but also hides in interactions between environmental, social and economic factors before the flood incident. While ecological resilience reflects the dynamic characteristics of resources, ecological vulnerability systematically describing aspects of stress was less researched. This paper develops a concept, modeling dynamic interactions between stress and resources taking into account of context, space, time, and stakeholder involvements, to provide direct causes and solutions for flood risk management. The paper reviews three major schools of thought concerning (i) vulnerability and resilience are two sides of the same coin, (ii) resilience is a part of vulnerability, and (iii) they are two separated concepts with some overlaps. Limitations of the schools of thought were recognized based on four main criteria: (i) vulnerability and resilience must reflect all social, economic and environmental aspects, (ii) they exist regardless of hazards, (iii) they are processes than outcomes, and (iv) they entail multiple objectives. Inspired by the flipping coin and separated concepts, a new framework has been developed. It acknowledges from outstanding points of the two that vulnerability and resilience are normalized as stress and resources of the same coin. Additionally, they can generate positive and/or negative outcomes. Therefore, their relationships are complex because resources, defined by stakeholders, may prevent system changes and consequently amplify stress. Depending on the ratio between stress and resources, a system can be characterized as a 'resistant', or a 'creative' regime. If incremental disturbances exceed the recovery threshold as defined by the available data and the stakeholders, the system might change regime. Decision makers can take advantage of this framework to prepare appropriate resources that increase the resilience of the community and anticipate adverse effects for incoming floods.
Effect of some effective parameters on COD Removal from Nam Son Landfill Leachate by electrocoagulation
Authors: Le Son Thanh , Le Khai Cao , Doan Linh Tuan , Doan Anh Thi
Published: April 2018

Leachate becomes ahead of wastewaters as being the most difficult to treat due to its complex and widely variable composition. In this research, the leachate treatment performance by electrocoagulation (EC) was studied. The samples of leachate were taken from Nam Son landfill in Hanoi. The effects of factors namely current intensity, electrolysis time, initial pH and anode materials on the EC performance were investigated via chemical oxygen demand (COD) removal efficiencies. The input leachate properties were obtained as COD, NH4+ and pH in the range of around 6247 ± 295, 1270 ± 38 mg/l and 8 ± 0.1, respectively. Mono-polar electrocoagulation unit was carried out in a batch system for leachate treatment with iron electrodes and approximately 1.8 litter of leachate. Firstly, with the increase in current (1 to 4A), the COD removal efficiencies increased from 50.00 to 78.57% (pH = 8 and operating time = 40 min). Secondly, by the increase in operating time, the treatment performance also went up significantly in first 40 min, then nearly level-off at above 73 % (pH=8, current intensity = 3A). In addition, the effect of pH in range of 5 to 10 on the electrocoagulation process was studied and showed the highest treatment efficiencies in neutral and mild alkaline medium, especially between 6 < pH < 8. Finally, the electrode materials made of iron and aluminum was investigated and the result indicated that when the iron anodes were replaced by aluminum, the COD removal efficiency experienced a considerable decline, from 70 to 37.93% (pH = 8 and operating time = 40 min). In combination of all experiments, the optimum operating conditions were achieved as iron electrodes, current intensity of 3A, electrolysis time of 40 min, the raw pH with iron electrodes, resulting the maximum COD removal efficiencies of 73.21%. As a result, the electrocoagulation can be applied to leachate pre-treatment.
Experimental cultivation of Spirulina platensis using My An mineral water, Thua Thien Hue province
Authors: Vu Nguyet Thi , Dang Kim Dinh , Nguyen Chuyen Hong , Vu Tam Thi Thanh , Tran Ha Phuong , Pham Cuong Viet , Ton That Huu Dat , Hoang Ngoc Phan Bich , Nguyen Thuy Thi Thu
Published: April 2018

Spirulina platensis was experimentally cultivated by semi-continuous method at 20m2 scale pilot to effectively use the available bicarbonate and minerals of the My An mineral water, Phu Vang district, Thua Thien Hue province, and reduce production cost. Analyses of My An water quality showed that this mineral water source was suitable to cultivate Spirulina Platensis after removing H2S. The average algal yield reached to 10gDW/m2.day. The obtained algal biomass contained high nutrient compositions and was a suitable source for functional food (68.32 % protein, 7.32 % lipids containing Omega-3 and Omega-6, and low heavy metal concentration). The obtained results indicated that the My An mineral water source was indeed a suitable water source for producing Spirulina platensis biomass as a functional food.
APPLICATION OF LACTIC ACID IN PRESERVATION OF NINH THUAN GREEN GRAPES NH01-48
Authors: Hanh Nguyen Thi
Published: April 2018

Ninh Thuan green grapes NH01-48 is popularly cultured in Ninh Thuan province. However, due to the lack of preservation technology and/or facility, Ninh Thuan grapes are transported to and consumed in other areas of the country in a limited volume. This study aimed to assess application of lactic acid in treatment of Ninh Thuan grapes for preservation. Effect of lactic acid on grapes with or without challenging microorganisms was examined. Green grapes NH01-48 was washed with sterile water, and then dried on air. Grapes were challenged with a cocktail of microorganisms previously isolated from Ninh Thuan grapes, including four bacterial strains (Bacillus cereus, Pseudomonas oryzihabitans, Citrobacter sp., and Flavobacterium sp.), three yeast strains (Wickerhamomces anomalus, Hanseniaspora opuntiae, Debaryomyces nepalensis) and one fungus Penicillium sp. at 5 × 104 CFU/ml. Then grapes were treated with 3 % lactic acid solution for 5 min (soaking) prior to be packed in plastic bags with punched hole of         3 mm diameter, distance between holes is 3 cm and preserved in refrigeration condition at                 4 ± 0.5 oC. Grapes without challenging microorganisms/without acid pretreatment/without challenging microorganisms but treated with acid were used for comparison. Samples were taken every 5th day until 30 days. Color, hardness, total dry matter, titration acidity, and total microorganism count were measured. Results showed that when applied treatment of lactic acid on grape with and without challenging microorganisms, the change in grapes’ hardness, color, dry matter and titration acidity was minimized, demonstrating positive activity of lactic acid on grape physicochemical characteristics. Samples without lactic acid treatment were spoiled after 15-20 days of preservation, whereas the ones with acid treatment can be last for at least 30 days. Moreover, number of total microorganisms count after 30 days of preservation were acceptable in samples with lactic acid treatment (ca. 103 CFU/g). Therefore, lactic acid can be potential for application in grapes preservation. The combined effect with other preservation techniques needs to be further studied.
ISOLATION AND SELECTION OF AFLATOXINS PRODUCING ASPERGILLUS FLAVUS FROM PEANUT
Authors: Phuong Thao Le Thi
Published: April 2018

Aspergillus flavus is known as the main producer of carcinogenic aflatoxins. The presence of this fungus and aflatoxins is an important impactson food safety, human and animal health. Peanut is one of the most important crops in Vietnam and  is suitable to substrate for aflatoxins producing fungus growth. The isolation and identification of Aspergillus flavus species from peanut is an initial step for further study in Aflatoxins contamination control in peanut. 28 peanut samples selected in Luc Nam district - Bac Giang province were used for fungus isolation. The isolated fungus were purified, conducted DNA extract, amplified PCR products then performed sequencing ITS gene and used BLAST software to check alignment to identification the strains. As the result, 4 strains alignedwith Aspergillus flavus strains from National Center for Biology Information - United Nation such as: TUHT115, KP214054.1, MTCC 8654, ZJ4-A. Those strains were checked and confirmed the aflatoxins production in peanut samples.
ANTIOXIDANT ACTIVITIES OF HYDROLYSATES ORIGINATED FROM SOYBEAN AND SOY MILK RESIDUE
Authors: Ngoc Ngo Minh
Published: April 2018

Soybean (Glycine max) and soy milk residue (okara) are protein-rich materials. Soybean possesses the highest protein content among different types of beans (protein content of soybean varies from 40–42 %). Soy milk residue, a by-product of the soy milk manufacturing industry, contains approximately 27 % protein (by dry weight). A number of recent studies have investigated the improvement of functional properties of protein contained in soybean and okara by fermentation or by the use of proteolytic enzymes. The aim of this study was to evaluate the antioxidant activities of soybean and okara hydrolysates obtained by the fermentation with Aspergillus oryzae or by using proteolytic enzymes (neutrase and flavourzyme). DPPH radical scavenging assay was used to determine the antioxidant activities of hydrolysates. The concentration of peptides required to scavenge DPPH radical by 50 % (IC50 value) was used to evaluate the antioxidant activity of peptides produced obtained from hydrolysates. The results showed that when fermented with A. oryzae, the okara hydrolysate had higher antioxidant activity than the soybean hydrolysate, with IC50 values of 0.447 mg/ml and 3.95 mg/ml, respectively. The hydrolyzed okara obtained from hydrolysis using Neutrase had higher antioxidant activity than the one obtained from hydrolysis using Flavourzyme, with IC50 values of0.200 mg/ml and 0.407 mg/ml, respectively. Different peptide fractions obtained from the hydrolysates using cut-off membrane (10 kDa, 3 kDa and 1 kDa) possessed different antioxidant activities. The < 1 kDa peptide fraction exhibited the highest antioxidant activity with an IC50 value of 0.158 mg/ml.
DISCRIMINATION OF GEOGRAPHICAL ORIGIN OF TEA BASED ON MULTI-ELEMENT FINGERPRINTING BY INDUCTIVELY COUPLED PLASMA OPTICAL EMISSION SPECTROMETRY AND ATOMIC ABSORPTION SPECTROMETRY
Authors: Thao Nguyen Thi
Published: April 2018

The metal content of 49 tea leaf samples from three different provinces inVietnamwere determined using inductively coupled plasma optical emission spectrometry (ICP-OES) and atomic absorption spectrometry (AAS). Total 18 elements in tea leaves were determined including macro element such as Al, Ca, K, Mg, Mn; trace element such as Na, Ba, Fe, Cu, Zn, B and heavy metals (Pb, Cd, Hg, Ni, Se, Sn) and metalloid (As). There was a wide variation of metal contents among the tea leaves coming from different province in which K content was the highest in all the tea leaf samples from the three provinces, followed by Ca, Mn and Al content. Principal component analysis (PCA) was applied in order to determine the different amount of metals as main sources of variability in the data sets and to establish the relation between samples and metal contents (variables). Linear discriminant analysis (LDA) was used to explore the different tea samples grouping according to the metal contents. Among the 18 elements found in the composition of tea leave samples, the LDA shows that Fe, Mg, Cd, and As are components with major discriminating power for the samples. This confirms that tea from different province shows unique elemental fingerprint characteristics that can be differentiated one from another and both techniques (PCA and LDA) are able to create for clear separation of tea leaf from identical province. However, LDA method could provide better discrimination of tea geographical origin over the PCA method.
INFLUENCES OF TECHOLOGICAL HYDROLYSIS CONDITION ON NUCLEIC ACID CONTENT OF SPENT BREWER’S YEAST HYDROLYSATE
Authors: Thanh Ngoc Nguyen Thi
Published: April 2018

Currently, with the strong increasing of the brewing industry output, the consequencing amount of yeast residue is very large. Utilizing a large source of protein from brewers yeast to produce hydrolysed products using protease as food and food additives has a high real-life benefit. However, one limitation in the use of yeast and hydrolysis products is that the amount of nucleic acid in the yeast in particular and in the microbial cells is generally high. Nucleic acid is abundant in food that causes gout in humans and animals. There are many methods for reducing or separating nucleic acids in hydrolysed products such as extracellular ribonuclease enzymes, chemical agents, thermal shock and autolysis. Use extracellular ribonuclease enzyme for hydrolysis of nucleic acid gives good efficiency, but with high production cost. Chemical agents affect the quality of the hydrolysed products used in the food industry. There have been many good-efficiency studies using heat shock and autolysis to reduce the amount of nucleic acid in the hydrolysate. However, no research has been conducted to reduce the amount of nucleic acid by hydrolysis techniques. In this paper, we investigated the effects of heat shock, autolysis and hydrolysis techniques (batch, continuous overflow and continuous circulation) of brewery yeast protein to nucleic acid content in yeast hydrolysate. The results showed that the content of nucleic acid in the hydrolysate (with a concentration of 55 % dry matter) was the smallest. Under normal hydrolysis conditions, the nucleic acid content was 8.7 g / kg and when there was a heat shock+ autolysis, it decreased to 6.34 g/kg. After optimizing the hydrolysis conditions, the nucleic acid content of the hydrolysate was reduced to 5.41g/kg on continuous hydrolysis system.
EXTRACTION OF PECTIN FROM PASSION FRUIT PEEL FOR PRODUCTION OF PECTIC OLIGOSACCHARIDES (POS)
Authors: Xuan Sam Nguyen Thi
Published: April 2018

Passion fruit peel obtained after juice extraction was used for extraction experiments of pectin. The effect of pH, water to peel ratio, and number of extractions, extraction time and temperature on the yield and quality characteristics of pectin were investigated. The optimized conditions for extraction of pectin frompassion fruit peel yielded 2.5 g/100 g of fresh peel.Powder pectin extracted from the fresh peels had pectin content of 95 %. The average degree of esterification of pectin was found to be 35-45 % and did not contain pathogenic microorganisms so it is suitable as a raw material for pectic oligosaccharide (POS) production
XÂY DỰNG QUY TRÌNH XÁC ĐỊNH β2-AGONIST TRONG THỊT, GAN, THẬN HEO BẰNG PHƯƠNG PHÁP QUECHERS KẾT HỢP VỚI UPLC-MS/MS
Authors: Giang Nguyễn Hương
Published: April 2018

Trong nghiên cứu này, chúng tôi đã xây dựng phương pháp xác định dư lượng thuốc thú y (Salbutamol, Clenbuterol và Ractopamine) trên nền gan, thịt và thận heo bằng phương pháp QuEChERS có sử dụng nội chuẩn đồng vị, phân tích trên hệ thống sắc kí lỏng khối phổ ba tứ cực (UPLC-MS/MS) cho độ chính xác cao và tin cậy với giới hạn phát hiện thấp (0,06 µg/kg), độ thu hồi và độ lặp lại cao phù hợp với quy định 2002/657/EC của Ủy ban Châu Âu.