bluuebunny/crossref_metadata_2025 huggingface dataset:
REMOVAL OF COD AND AMMONIUM FROM LANDFILL LEACHATE BY USING A MODIFIED ECO - BIO – BLOCK MATERIAL IN ANOXIC-OXIC SYSTEM
Authors: Luong Hoang
Published: April 2018

The research on removal efficiencies of COD and NH4+ in landfill leachate by an application of the modified Eco - Bio -Block (EBB) material in Anoxic-Oxic (A-O) system was conducted in the laboratory scale. The experimental results showed that the treatment efficiencies of COD and NH4+ were relatively high. Removal efficiencies of COD and NH4+ in two columns (anoxic and oxic) were 35% and 50%, respectively, after 19-hour in the experimental system at the flow rate of 1 liter per hour. The results of this study might suggest technical solutions toward landfill leachate treatment at the low cost. Moreover, this method could be widely applied to other wastewater sources suitable in the condition of Vietnam.
DETERMINATION OF PROPERTIES AND ELEMENTAL COMPOSITION OF MUNICIPAL SOLID WASTE IN ORDER TO PROPOSAL OF WASTE-TO-ENERGY PROJECT IN BINH DUONG PROVINCE
Authors: Vy Phung Chi
Published: April 2018

Domestic solid wastes are classified into 10 samples of 04 groups with different sizes: 2 samples with sizes under and over 120 mm (M1-1, M1-2); 2 samples with sizes under and over 80 mm (M2-1, M2-2); 2 samples with sizes under and over 40 mm (M3-1, M3-2); 4 samples with sizes under 40 mm, 40 to 80 mm, 80 to 120 mm and over 120 mm (M4-1, M4-2, M4-3, M4-4). Results of sorting 10 solid waste samples into food, cloth, wood, plastic, paper, rubber/leather, metal, glass, other organic and inorganic components shown that recycled combustible, non-recycled combustible portions are ranged from 15,46 to 93,90 %, from 5,34 to 80,17 %, respectively. The density of 10 compressed garbage samples is ranged from 525,9 to 2016,7 kg/m3; moisture contents are ranged from 18.03 to 20.92 %. Ash content is ranged from 1.12 to 9.49 % dry weight; Calorific value is ranged from 3164,9 to 5757,0 kcal/kg of garbage. The volume of leached water from 10 kg wet garbage pressed by 250 kg load in 2 days is 300 ml (equivalent to 327,1 g). Results of elemental composition analysis shown that the contents of C, H, N, Cl, S are ranged from 35,00 to 51,96, from 6,01 to 6,23, from 0,41 to 0,88, from 0,44 to 0,56, from 0,14 to 0,84 %, respectively. On this basis, the author have proposed a waste-to-energy plant with capacity of 250 tons of waste/day to generate the electricity with capacity of 17,0 MW/day.
CONSTRUCTED WETLANDS AS BIOFILTERS IN CLOSED RECIRCULATING TANK CULTURE SYSTEMS OF ASIAN TIGER SHRIMP (PENAEUS MONODON)
Authors: Diem Trang Ngo Thuy
Published: April 2018

The study was conducted to monitor the real-time status of toxic compounds to P. monodon in intensive recirculating aquaculture system integrated constructed wetlands (CWs) designed with surface flow (SF), vertical subsurface flow (VF) and horizontal subsurface flow (HF), and to examine removal efficiency of contaminants in different CWs. Plants used in the system were cattail (Typha sp.), elephant grass (Pennisetum purpureum) and unplanted systems used as referenced samples. Recirculating rate per day was 50 % of total water volume in tanks. Water from culture tanks was purified by passing through SF, VF and HF then return to original tanks without water exchange in entire study period. After 72 days, concentration of NO2-N, NH4-N and NO3-N was building up over study period and was not significantly different among treatment systems (except the concentration of NO3-N). At the end of study period, NH3 concentration was below the toxic threshold for P. monodon in according to Circular No. 45/2010/TT-BNNPTNT. P. monodon grew slowly and the survival rate was as low at 30 %, 43 % and 60,5 % in the HF, SF and VF systems, respectively. The average water volume added in each tank in entire study period was 393 ± 1,7 L. Despite of low survival and growth rates, the integration of CWs in intensively recirculating shrimp systems helps to improve water quality in accordance to Circular No. 45/2010, to diminish pollutant discharging and to maximize efficiency of water use which minimizes environmental pollution.
ASSESS THE DENITRIFICATION POTENTIAL OF FERMENTED BIOSOLIDS BASED ON THEIR SPECIFIC DENITRIFICATION RATE (SDNR)
Authors: Duc Phung Anh
Published: April 2018

The study examined the potential of fermented and dark-fermented biosolids as external carbon sources for denitrification improvement. This was done by up-scaling the selected two (out of seven) sludge fermentation conditions from past studies, carrying out ammonia stripping pre-treatment to fix the C/N ratio, before finding their specific denitrification rate (SDNR) using SDNR experiment set-up. The gotten SDNR were then compared to the SDNR of other substances gotten from both previous studies and literature, to weight the denitrification potential of fermented biosolids as a substance. The results found that with an initial COD of 607-704 mgCOD/L, the SDNR of the two fermented biosolids and dark fermented biosolids were found to be 8.35 ± 0.41 and 8.56 ± 0.71 respectively. This was much higher than the 1.53 -2.57 for sucrose and 1.29 ± 0.21 for wastewater found in earlier study using the same methodology; and comparable to the denitrification potential value for the well-studied methanol
SEWER DISCHARGE CHARACTERISTICS AND WATER BALANCE IN DRY SEASON IN HUE, VIETNAM
Authors: Quynh Anh Tran Nguyen
Published: April 2018

Vietnam has been developing sewerage recently. Although sewer discharge quantity and quality data is vital for proper sewage management, their fluctuation has not been well characterized in most of cities in developing countries. This study aimed to characterize a combined sewer discharge in a residential drainage area (11.2 ha) in Hue city, Vietnam on dry days in dry season (DdDs). A 24-hour survey on sewage quantity and quality was conducted at the sewer outlet on two weekdays and two weekends in July 2015. Household water consumption was hourly recorded from water meters for 23 households. Then results of discharge characteristics were compared with those on dry days in rainy season (DdRs) of our previous study. Results showed that hourly variations of flow rate corresponded to the water consumption trend. Average discharge flow rate was equivalent to 38.5 ± 4.4 L/cap/day, which was much lower than that on DdRs (64.2 ± 25.0 L/cap/day). In contrast, pollutant concentrations on DdDs were higher than those on DdRs and fluctuated slightly in a day and among days in a week. Low concentrations of discharge in both dry season and rainy season showed that domestic wastewater in urban Hue was not strongly polluted in terms of organic matter and nutrients. Sewer water balance showed that only 29 % of total water inputted to the sewer system was discharged through the outlet on DdDs, while the remaining 71 % was likely exfiltrated to the ground from the sewer system, which will be a potential pollution source to soil and groundwater.
STUDY ON CO-FERMENTATION OF COW DUNG AND GIANT DIRT IN SEMI-CONTINUOUS ANAEROBIC DIGESTER
Authors: Phuong Nguyen Le
Published: April 2018

Study on co-fermentation of cow dung (CD) and giant dirt (GD - Pistia stratiotes L.) in semi-continuous anaerobic digester aims to test biogas quantity and quality by time. Three mixing rates counted based on ODM of each material were chosen: 100 %CD, 50 %CD + 50 %GD, and 100 %GD. The experiments were set up in laboratory conditions with two types of digesters: one-stage digesters and two-stage digesters (triplicate for each treatment). After 80 days, the biogas produced from the one-stage digesters was not significantly different to the two-stage digesters with similar input material. The highest production of biogas came from digesters of 100 %GD - 235.8 L for the one-stage and 240.3 L for the two-stages. The medium production came from digesters of 50 %CD + 50 %GD - 127.8 L for the one-stage and 118.4 L for the two-stages. After one month, the percentage of CH4 was high enough for burning and almost giant dirt was digested that limited of a blockage inside the digesters. The results showed that co-fermentation of GD and CD is an alternative for livestock raising households to produce biogas for energy purpose.
SYNTHESIS OF N-ALKYL AMINO LACTAM DERIVATIVES
Authors: Dao Phi Thi
Published: April 2018

Bengamides are sponge-derived natural products of mixed biosynthesis (polyketides andamino acids), the first two members, isolated from Jaspidae sponges in coral surrounding Fijiislands, were reported in 1986. The main structural variation is located on the 3-aminocaprolactam moiety, and displays a wide range of biological activities, includingantitumor, antibiotic, and anthelmintic properties. These interesting biological activities havemade bengamides popular targets for synthesis and biological studies. There have been somereports on diverse modifications of the caprolactame unit, and indication that N-substitution oncaprolactam greatly influences the antitumor activity. In this paper, we reported the method forsynthesis of 6 amino lactams containing an additional N-alkyl group (4a-4c) and (8a-8c) forfurther synthesis of new bengamide analogues. Their structures were established by MS andNMR spectroscopies.
THERMOCHEMICAL PARAMETERS OF ERGOTHIONEINE: A DFT STUDY USING M06, WB97XD AND TPSSTPSS METHODS
Authors: Ngo Chinh Thi
Published: April 2018

Antioxidant properties of ergothioneine (ESH) have been investigated via hydrogen atomtransfer (HAT), single electron transfer-proton transfer (SET-PT) and sequential proton losselectron transfer (SPLET) mechanisms. Three new DFT methods including M06, WB97XD andTPSSTPSS at the 6-311++G(2df,2p) basis set were used to compute the thermochemicalparameters of ESH in the gas phase. Based on these methods, bond dissociation enthalpy (BDE),ionization energy (IE), proton dissociation enthalpy (PDE), proton affinity (PA) and electrontransfer enthalpy (ETE) were calculated. The results were also compared with the valuesobtained by B3LYP method. The calculated results show that ergothioneine plays a role as apotential antioxidant via HAT mechanism.
STUDY ON SOME FACTORS OF MAGNETIC FLUID CHITOSANCOATED Fe3O4 NANOPARTICLES FABRICATION VIA HYDROTHERMAL METHOD
Authors: Tam Le The
Published: April 2018

To optimize reaction conditions of hydrothermal preparation of crystalline magnetite(Fe3O4) nanoparticles, the influence of some experimental parameters (temperature, initialconcentration of ferric and ferrous ions, and heating time), and their interactions on the magneticnanoparticle formation was studied using response surface methodology (RSM), based on astatistical design of experiments (DOE). The variation in the particle diameter and crystallitesize of obtained magnetic nanoparticles (MNPs) with the synthesis conditions was examined andtransmission electron microscopy (TEM) and X-ray diffraction analysis. The results showed thatcrystallite size was greatly affected by temperature, ferric salt concentration and the heatingtime, whereas the particle diameter strongly depended on the heating time, and on the interactionbetween the initial ferrous/ferric ion molar ratio and the initial concentration of ferrous ions. TheMNPs produced by this method were the objects to coat surface with chitosan solution. Thechitosan coated MNPs are nearly spherical with a mean size from 10 to 20 nm depending on theexperimental conditions. RSM analysis showed that under optimized conditions, the chitosancoated MNPs with smallest size 13.43 ± 1.5 nm and saturation magnetization 68.12 emu/g atroom temperature were obtained under the hydrothermal temperature 165oC, heating time 2 h 55minute and ferric salt concentration 0.21 M.
ANTIOXIDANT AND ANTIBACTERIAL ACTIVITIES OF EXTRACTS FROM SEEDS OF MUSA BALBISIANA
Authors: Nghia Bui Tan
Published: April 2018

In this paper, some extracts from seeds of Musa balbisiana were prepared with somesolvents such as petroleum ether, ethyl acetate and buthanol. The results showed that themicrowave-assisted extraction had high yield. The buthanol and ethanol extracts showed goodantioxidant activity (using reaction with free radical DPPH, 1,1-diphenyl-2-picrylhydrazyl) withIC50 value of 182.6 and 301.8 μg/mL, respectively. The minimum inhibitory concentration MICof buthanol extract was 22.5 mg/mL with both Enterococcus faecalis and Staphylococcusaureus. Besides, the ethyl acetate extract had MIC value of 7.5 and 3.5 mg/mL for Enterococcusfaecalisand Staphylococcus aureus, respectively. From results of this study, these extracts arepromising for researches as well as applications in the future.
IN VITRO ANTIOXIDANT AND ANTIBACTERIAL ACTIVITIES OF FRACTIONATED EXTRACTS AND ISOLATION OF BIOACTIVE COMPONENTS FROM BREYNIA VITIS-IDAEA (BURM. F.) C. E. C. FISCHER LEAVES
Authors: Lan Hương Nguyễn Thị
Published: April 2018

This study investigated the antioxidant and antibacterial activities of ethyl acetate, nbutanoland ethanol extracts of Breynia vitis-idaea (Burm.f.) C. E. C. Fischer leaves using invitro assays;and isolated bioactive compounds from the fractioned extract which showed the bestproperties by column chromatography. All extracts showed significant radical scavengingactivities and exhibited antibacterial activities against Enterococcus faecalis, Staphylococcusaureus and methicillin-resistant Staphylococcus aureus (MRSA). Ethyl acetate extracts showedthe highest free radical scavenging capacity with the IC50 values of 99.55 and 94.66 μg/ml (inDPPH and ABTS assays, respectively) and exhibited MIC values of 1.5, 1 and 1 mg/ml againstthe three bacteria, respectively. In addition, from ethyl acetate extracts, one pure compound hasbeen obtained and identified as 6-O-benzoylarbutin.
STRUCTURAL CHARACTERISTICS AND ANTICOAGULANT ACTIVITY OF SULFATE POLYSACCHARIDE FROM THE BROWN ALGA SARGASSUM ALIQUALIUM
Authors: Nguyen Bui Van
Published: April 2018

Four fractions of sulfate polysaccharide extracted from the brown alga Sargassumaliqualium (Fucales, sargassaceae) were fractionated by using anion – exchangechromatography. Their structural characteristics were determined by desulfation, methylationand NMR spectroscopic methods. The results showed that four sulfate polysaccharides havebranched structure, their chemical compositions are galactose, fucopyranose, fucofuranose,mannose, some other monosaccharides and sulfate groups in different positions. The sulfatepolysaccharides from Sargassum aliqualium showed anticoagulant activity and higher sulfatecontent fraction has higher activity.
SEPARATION AND HPLC QUANTITATIVE ANALYSIS OF MURRAYAFOLINE A FROM THE ROOTS OF GLYCOSMIS STENOCARPA
Authors: Toan Tran Quoc
Published: April 2018

In this study, we investigated two methods for the separation and purification of alkaloidMurrayafoline A from the roots of the Vietnamese plant Glycosmis stenocarpa and developed anHPLC method for the determination of its contents in plant materials and the methanol extract.The yield of Murrayafoline A using steam distillation method was 1.5 times higher than theseparation method using column chromatography. By HPLC method, the content ofMurrayafoline A was determined to be 0.38 % (w/w) in the roots and 16.69 % (w/w) in themethanol extract of G. stenocarpa.
NGHIÊN CỨU MỘT SỐ HOẠT CHẤT SINH DƯỢC TRONG LOÀI TU HÀI LUTRARIA RHYNCHAEMA Ở VÙNG BIỂN VÂN ĐỒN QUẢNG NINH – VIỆT NAM
Authors: Nam Nguyễn Huy
Published: April 2018

Ngày nay với sự phát triển của y học hiện đại đã chứng minh rằng nhiều hoạt chất sinhdược có trong nguồn thực phẩm bổ dưỡng có tác dụng rất hiệu quả trong việc điều trị và phòngngừa bệnh tật. Đặc biệt là những nguồn thực phẩm có giá trị dược liệu từ động vật biển. Gầnđây, một nhóm các nhà khoa học đã nghiên cứu và phát hiện ra một số hoạt chất sinh dược cótrong loài tu hài Lutraria rhynchaema ở vùng biển Vân Đồn - Quảng Ninh - Việt Nam. Một sốhoạt chất steroid và các khoáng chất cần thiết cho cơ thể, cao nhất là ở loài tu hài trưởng thành12 tháng tuổi (MH1): Thành phần và hàm lượng các hormone steroid gồm có : testosterone (52,0mg/kg vck), cortisol (49,0 mg/kg vck), progesterone (37,5 mg/kg vck), estradiol (28,2 mg/kgvck). Hàm lượng các chất vi khoáng gồm có : Cu (65,30 mg/kg vck), Fe (182,0 mg/kg vck), Zn(132,22 mg/kg vck), Mn (82,0 mg/kg vck), K (0,160 %), Ca (2,10 %).
ERP IMPLEMENTATION IN HIGHER EDUCATION INSTITUTION: CASE STUDY AT FACULTY OF INFORMATION TECHNOLOGY
Authors: Phi Loan Nguyen Thi
Published: April 2018

Enterprise Resource Planning (ERP) solution has been implemented in many companies. Its implementation in higher education institutions is still limited. In this study, an implementation of ERP in higher education institutions is presented. The implementation is performed at the faculty of Information technology based on the Odoo platform which is an open source ERP system. The analysis is performed based on the critical success factors.
A LOSSY CODING SCHEME FOR IMAGES BY USING THE HAAR WAVELET TRANSFORM AND THE THEORY OF IDEAL CROSS-POINTS REGIONS
Authors: Tin Dang Thanh
Published: April 2018

This paper presents Lossy Coding Scheme for Images by Using The Haar Wavelet Transform and The Theory of Cross-points Regions with Ideal Cross-points Regions (HWTICR). The base of this statement is the effect of Gray coding on cross-points which are neighbor to the points of grey levels 2n. After Gray coding these regions always contain only 1-bits or 0-bits depending on the number of each bit plane after bit plane decomposition. The optimization of probability in each bit plane has important effects on encoding and decoding processes of lossless image compression for data transmission. The framework itself is founded upon a wavelet transformed domain, the scheme will show how The Haar Wavelet Transform combines with the theory of Ideal Cross-points Regions to become a lossy coding scheme for images. The goal of the method is to build a lossy coding scheme for images with high compression ratio and low distortion factor in comparison with some other methods. Finally, some initial results of the scheme are also presented and compared to the other methods. The algorithm can be used in medical and photographic imaging.
ANTIOXIDANT, α-GLUCOSIDASE INHIBITORY AND ANTIFUNGAL ACTIVITIES OF EXTRACTS FROM LICHENS COLLECTED IN VIET NAM
Authors: Huỳnh Thu
Published: April 2018

Lichens are one of the earliest colonizers of terrestrial habitats on the earth. They are a unique life form of symbiosis between fungi (mycobionts) and algae and/or cyanobacteria (photobionts). Lichens have been used as a cure for diabetes, coughs, pulmonary tuberculosis, wound curing, and dermatological diseases. The aim of this study is to evaluate the antioxidant, α-glucosidase inhibitory and antifungal activities of methanol extracts of lichens from eleven lichen species isolated in Viet Nam including Usnea, Lobaria, and Parmotrema were evaluated. The antioxidant activity was determined by ABTS radical scavenging activities. The results indicated that eleven species of lichens extracts possessed relatively high antioxidant activity with IC50 values ranging from 21.59 to 570.85 µg/ml for 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging assay. The extracts of U101 was more efficient for α- glucosidase inhibitory activity, with the IC50 value of 75.23 ppm. In addition, all extracts also exhibited inhibitory activity on the growth of Aspergillus fumigatus (17.5 – 32.7 %) and Penicillium sp. (16.7 – 33.4 %).
CHOLINESTERASE IMMOBLIZATION FOR LARGE-SCALE PRODUCTION OF HIGH SENSITIVE TEST CARDS FOR RAPID DETECTION OF ORGANOPHOSPHORUS AND CARBAMATE PESTICIDES IN AGRICULTURAL PRODUCTS
Authors: Cuong Do Bien
Published: April 2018

A single step test card for field screening of pesticide residues in vegetables based on simultaneous inhibition and reaction of cholinesterase was previously proposed. Here, favorable conditions to immobilize cholinesterase on filter paper for bulk production of this test card were developed. An amount of 28 mL of 6 U/mL cholinesterase solution was sprayed onto a filter paper sheet (210 mm × 297 mm) with speed of 1.5 mL/s. After incubation at -20 ◦C for 60 min, enzyme coated-papers were dried at 60 ◦C for 30 minutes and stacked on indicator and substrate-coated papers. The stack was cut into 10 mm × 10 mm-sized pieces for depositing on metallised polyester film sheets. Then another metallised film which holed 5 mm diameter holes was placed on the paper pieces, and 15 mm × 15 mm reaction windows were made by heat pressing. The developed test card’s detect limit by naked eyes ranged between 0.0001 and 0.1 ppm of organophosphorus pesticides. This high sensitive test card provides a useful tool for detection of toxic organophosphorus and carbamate compounds in agricultural products, food and environment with cost-effective, minimized reagent consumption, and simple operation.
OPTIMIZATION OF CONDITIONS FOR LIMITED PROTEOLYTIC HYDROLYSIS OF SPENT BREWER’S YEAST TO PRODUCE LOW-WEIGHT MOLECULAR PEPTIDE WITH SOME BIOACTIVITIES
Authors: Thu Hien Pham Thi
Published: April 2018

Spent brewer’s yeast (Saccharomyces cerevisiae) is a rich source of protein, vitamins and widely used as a raw material for producing bioactive compounds and food ingredients. In the present study, the Box-Behnken design was used to determine the optimal conditions for hydrolysing spent brewer’s yeast using protease (Neutrase) to produce low- weight molecular peptide. The spent brewer’s yeast concentration, concentration of protease, and hydrolysis time are the most important factors used to optimize the protein hydrolysis. For achieving high yields of peptide, the hydrolysis conditions were determined: yeast concentration of 22.72 % (w/w), protease concentration of 4.07 % and hydrolysis time of 16.73 hours. The maximum yield of low-MW peptides was achieved 223.18 mg/g. The obtained bioactive peptide showed capability of antibacterial against Salmonella typhi, Listeria monocytogenes, Staphylococcus aureus and high antioxidant activity at peptide concentration of  100 (µg/ml).
TỐI ƯU HÓA MỘT SỐ THÔNG SỐ CÔNG NGHỆ BẢO QUẢN QUẢ THANH LONG BẰNG KĨ THUẬT BAO GÓI KHÍ ĐIỀU BIẾN
Authors: Tuấn Phạm Anh
Published: April 2018

Mục tiêu của nghiên cứu này là xác định được vật liệu bao gói phù hợp và tối ưu hóa hai yếu tố thực nghiệm gồm tỉ lệ diện tích màng bao bì/khối lượng quả (cm2/g) và độ dày màng bao bì (mm) có ảnh hưởng đến điều kiện cân bằng nồng độ khí oxy (%) và nồng độ khí cacbonic (%) trong môi trường vi khí hậu của màng bao bì bảo quản quả thanh long. Kết quả thực nghiệm đã xác định được vật liệu màng bao gói LDPE có khả năng thẩm khí phù hợp cho bảo quản quả thanh long. Kế hoạch thực nghiệm đa yếu tố gồm 9 thí nghiệm với khoảng khảo sát của 2 yếu tố thực nghiệm: tỉ lệ diện tích màng bao bì/khối lượng quả từ 1,80 - 2,20 cm2/g, độ dày màng bao bì LDPE từ 0,02 - 0,04 mm,  nguyên liệu thanh long sau khi sơ chế, bao gói được tồn trữ ở nhiệt độ 4 ± 1 oC và độ ẩm 90 - 95 %. Kết quả tối ưu đã xác định được tỉ lệ diện tích màng bao bì /khối lượng quả thanh long là 1,96 cm2/g và độ dày màng bao bì LDPE dày 0,03 mm, tương ứng trạng thái cân bằng môi trường vi khí hậu ở nồng độ khí oxy 3,82 %, nồng độ khí cacbonic 5,84 %. Chất lượng mẫu thanh long ở điều kiện tối ưu được đánh giá sau 20 ngày bảo quản với hàm lượng đường tổng số 7,98 %, hàm lượng vitamin C 7,5 mg/100 g, cảm quan 18,2 điểm.
EXPRESSION OF GLUTARYL7-AMINOCEPHALOSPORANIC ACID ACYLASE IN ESCHERICHIA COLI BL21(DE3) AND IMMOBILIZATION OF RECOMBINANT ENZYME ON NANOPOROUS MATERIALS
Authors: Hanh Vu Thi
Published: April 2018

The synthesis of 7-ACA from cephalosporin C (CPC) by a two-step bioconversion using D-amino acid oxidase (DAAO) and glutaryl 7-ACA acylase (GLA) has been effectively and largely applied in pharmaceutical industry. In this study, the gene gla coding for 720-amino acid GLA from plasmid pUC57::gla was analyzed and successfully inserted into vector pET22b(+) to form expression vector pET22b(+)::gla. The newly constructed expression vector pET22b(+)::gla was cloned and then transformed into Escherichia coli BL21(DE3) to generate recombinant strain E. coli BL21(DE3)[pET22b(+)::gla]. The suitable conditions for expression of gla gene were in LB medium at 30 oC and induced by 0.4 mM of Isopropyl β-D-1-thiogalactopyranoside (IPTG) for 3 hours. Under the chosen culturing parameters, expression of gla gene by E. coli BL21(DE3)/[pET22b(+)::gla] resulted in a recombinant GLA (rGLA) with molecular weight of 83 kDa and catalytic activity of 2.7 U/mg of total protein. Experimental research on immobilization of rGLA onto ten nanoporous materials were showed that, SBA-15 was the best one for immobilization of rGLA, reaching activity of immobilized enzyme of 22.2 U/g matrix. Furthermore, optimal conditions of procedure for immobilizing rGLA on nanomaterials (SBA-15) were determined as follows: temperature is 25 °C, pH7.0 and immobilization time –60 minutes. Therefore the results reported in this study revealed the successfully heterologous expression of GLA in recombinant E. coli and potential immobilization of enzyme on inorganic nano-materials.
STUDY ON POLYVINYL ALCOHOL GEL BEADS AS BIOCARRIER APPLIED IN ANAEROBIC SLUDGE IMMOBILIZATION IN THE UASB REACTOR
Authors: Tai To Tien
Published: April 2018

In this study, the biocarrier was made of 8 % (w/v) polyvinyl alcohol (PVA) solution dropped into saturated solution of boric acid (6 %, w/v), then immersed for 2 hours to form PVA-boric bead. In order to maintain the crosslinked beads, it is subsequently immersed in 1M sodium sulfate solution for 1 hour. PVA gel beads have the diameter of 3.5 - 5.0 mm, a specific gravity of 1.03 - 1.08 g/cm3, high mechanical strength and good elasticity. The surface and internal structure particle were observed under a scanning electron microscope (SEM). The application of PVA beads in microbial immobilization was initially examined in three UASB reactors treating rubber wastewater with sludge and PVA beads ratios of 1/1, 2/1, 3/1 (v/v), respectively. Promising result of bio-immobilization was achieved, at ratio of 1/1, the SMA of PVA beads was 0.133 g COD/gVSS/day, corresponding to 17 % of the suspended sludge’s value in the same reactor and the attached biomass was 0.936 g VSS/g dried PVA bead after 90 days.
EFFECT OF PRECURSOR MATERIALS AND HYDROTHERMAL TIME ON THE MORPHOLOGY, MICROSTRUCTURE AND PHOTOCATALYTIC ACTIVITY OF TiO2 NANOTUBES
Authors: Le Thi Ngo Tu
Published: April 2018

In this study, effects of precursor materials and hydrothermal reaction time on the morphology, microstructures and photocatalytic activity of TiO2 nanotubes (TNTs) were investigated. Results show that the selection of nanopowder TiO2 precursors and hydrothermal time has significantly affected the morphology, microstructure and photocatalytic property of TiO2 nanotubes. TNTs–Merck was fabricated from TiO2–Merck precursor at 130 °C for 22 h possesses a uniform structure with a range of the diameter of ~ 10 nm and length of ~ 100 nm.
DISTRIBUTION AND SOURCES OF POLYCYCLIC AROMATIC HYDROCARBONS IN AQUATIC SEDIMENT FROM CAN GIO COASTAL WETLAND, HOCHIMINH CITY
Authors: Thanh Thuy Hoang Thi
Published: April 2018

The distribution of fifteen polycyclic aromatic hydrocarbons (PAHs) indicated from USEPA as priority pollutants was studied in surface sediments (0 - 20 cm) of coastal wetland area of Can Gio district, Hochiminh City. PAHs were recovered from the sediments by solvent extraction and then analyzed by means of high performance liquid chromatography system. Total concentrations of the ∑PAHs in the range 5 – 38 ng/g dw were detected, and a distinct spatial trend was observed. The contents of Nap, Ace, Flu, Phe and dBA were below detection limit. Diagnostic ratios such as benzo[a]anthracene/chrysene and fluoranthene/pyrene were achieved to evaluate the emission sources of PAHs. These ratios indicated an anthopogenic source (pyrolysis) of PAHs for sediments. Furthermore PAHs were associated mainly with fine particle sediments. Although the PAHs contents were below Vietnamese standard but potential risk to ecosystem needs further study since the high percentages of carcinogenic PAHs.
A STUDY ON IMPACT OF CLIMATE CHANGE TO SALINITY AT WATER INTAKE POINTS OF SUPPLY WATER FACTORIES AND ADAPTATION SOLUTIONS PROPOSAL
Authors: Nguyen Ky Phung
Published: April 2018

The paper presents a research on impact of climate change to salinity at water intake points of supply water factories and proposes adapting solution. In the research, the change precipitation induced flow as well as the change of discharge of reservoirs flow according to climate change scenarios are calculated by NAM and regulation of reservoirs models. These flows will be upstream boundary data for Mike 11 model to simulate salinity intrusion on the whole system, and sea level rise condition will be the downstream boundary data. After calculating salinity change at water intake points, solutions will be proposed based on simulation results as well as supply water planning under climate change condition.
COMMUNITY PARTICIPATION IN RURAL WATER SUPPLY: A CASE STUDY IN MY HOA – TRA VINH
Authors: Thuy Nguyen Thi
Published: April 2018

This study examines the level of community participation in rural water supply in Vietnam from two approaches: (1) the legal documents at the top level as well as implementing guidances and (2) the case study of community practice and awareness about their role in local water supply. Rural water supply policy and regulations are assessed to point out how they allow and support community participation. A survey conducted in My Hoa commune, Tra Vinh province, with the total of 152 households, reveals the levels and types of the community participation, from which some lessons learned can be drawn. The engagement of the community in monitoring and maintenance of the water supply infrastructure is seen as a key for the sustainability of the clean water supply service. Recommendations are given to improve community participation, and therefore to have better clean water supply service in rural areas.
ELECTROSPUN CHITOSAN/PVA NANOFIBERS FOR DRUG DELIVERY
Authors: Hong Thien Doan Van
Published: April 2018

Electrospinning technique is a versatile method to fabricate continuous fibers with diameters ranging from a few micrometers to a few nanometers. In this study, chitosan/ poly (vinyl alcohol) (PVA) nanofibers were fabricated by an electrospinning method. The effects of chitosan molecular weights and ratio of chitosan/PVA were studied. The characteristics and surface morphologies of nanofibers were observed by the Scanning Electron Microscope (SEM). The diameters of nanofibers were in the range of 100 nm to 250 nm. The chitosan/PVA nanofibers with different molecular weights were applied for curcumin delivery. Curcumin was loaded in the chitosan/PVA nanofibers. Then, release profile of curcumin was investigated. In the results, the encapsulation efficiency and the release rate demonstrate that chitosan/PVA nanofibers would be potential carriers for curcumin and promise to create a prospective drug delivery in the field of medicine.
EFFECT OF ORGANIC LOADING RATE ON SIMULTANEOUS REMOVAL OF NITROGEN AND PHOSPHORUS FROM AQUATIC PRODUCT PROCESSING WASTEWATER BY ADVANCED A2/O – BAF SYSTEM
Authors: Quynh Nhu Nguyen Xuan
Published: April 2018

Combined system of Anaerobic/Anoxic/Oxic reactor with Biological Aerated Filter (A2/O – BAF) is used to enhance simultaneous removal of nitrogen and phosphorus on aquatic product processing wastewater treatment. A2/O reactor was operated with short solids retention time employed mainly for removal of organic matter and phosphorus together with denitrification and BAF with long solids retention time employed mainly for nitrification. The model of combined A2/O – BAF system made from polyacrylic with the capacity of 49.5 liters was operated with hydraulic retention time decreased from 19.2 to 9.6 hours and organic loading rates increased from 0.50 to 1.0 kgCOD/m3/day.  The results showed that the model not only treated organic matter well but also removed nearly completely both nitrogen and phosphorus. For loading rate of 0.75 kgCOD/m3/day, treatment efficiencies of COD, NH4+-N, TN, TP of the model were the highest as 91.02, 96.82, 84.08, 86.66  %, respectively and output values of these parameters were within the limits of QCVN 11:2008/BTNMT, column A.
ASSESSING METAL POLLUTION IN GROUNDWATER AT PLEISTOCENE AQUIFER IN GO VAP DISTRICT, HO CHI MINH CITY
Authors: Phi Oanh Tran Thi
Published: April 2018

The appearance of some metals such as Fe, Al, As and other compounds with artificial origin as Zn, Cu, Pb in groundwater has become issues and being interested to many researchers. In the area of water supply, the problem of metal pollution from some water supply companies and households not only appears in surface water but also in groundwater, which reflected in the metal contamination over permissible standards and seasonal oscillations. In this study, a survey of current pollution was carried out to elucidate the distribution of some metal ions such as total iron, Al3+, As5+, Cu2+, Pb2+ and Zn2+ in groundwater in Go Vap District. The results showed that these metals are distributed mainly at mid-upper Pleistocene aquifer (qp2-3) from 8 meters to over 40 meters and in strongly to moderately acidic environment, which have pH from 4.2 to 5.0. As results, this study shows that these metals in groundwater related to the origin and sediments composition of permeable and impermeable aquifers. In addition, the metal pollution such as Cu2+, Pb2+ and Zn2+ in recent years may be due to the artificial origin.
CHALLENGES IN THE IMPLEMENTATION OF SOLID WASTE MANAGEMENT STRATEGY IN THE CENTRAL HIGHLANDS OF VIETNAM
Authors: Phuong Nguyen Hoang
Published: April 2018

The Central Highlands of Viet Nam has a large area of 56,638.44 km2 and is characterized by owning different types of topography, a thin population density (95 people/km2), a limited literacy level but rather high economic growth rates (average of 12.84 %/year for the last few years). Besides, the municipal model for solid waste management (SWM) currently practiced in the Central Highlands appears to be ineffective due to, among other reasons, the limited capability of solid waste collection and transportation in the rural areas. Results of this study show rather poor collection rates in the region, ranging from 25.8 % in Dak Nong to 77.6 % as highest in Lam Dong. These figures have obviously not met the targets set for 2015 as required by the “Vietnam National Strategy for Integrated SWM till 2025, with a vision to 2050”. Based on the characteristics of natural environment, socio-economic and local culture values of the study area, a combination of regional SWM and ecological modernization theory (EMT) has been analyzed in this research. As a result, this study points out the way for improving the current SWM in the Central Highlands by, among other measures, rerouting the regional solid waste collection and transportation; Last but not least, the study concludes that in order to improve HDI in the Central Highlands to the average nationwide value of 0.753, it is unrealistic to be based only on GDP growth. Instead, however, it could be realistic if IGDP increases at only 2 - 3 % with an increase of Ieducation and Ilife time at about 5 %.
ANGLE-DEPENDENT TRANSMISSION FOR VISIBLE LIGHT OF MAGNETIC GRANULAR THIN FILMS
Authors: Cuong Giap Van
Published: April 2018

The transmission for visible light (T), with wavelengths from 560 to 695 nm, was investigated at various light incident angles of 0 ¸ 45 degree for the surface normal of samples (φ) as a function of Co contents for magnetic granular films Cox-(Al2O3)1-x, where x = 0.10 ¸ 0.45. This investigation was carried out under an external magnetic field fixed at 4 kOe to ensure for all the Co-granule magnetization being kept in a fixed incident light propagating direction. Results showed a rather remarkable angular dependence of T(φ) on the Co content for different wavelengths. It was attributed the behavior of this to be dependent on the so-called magnon-photon interaction.
NGHIÊN CỨU KHẢ NĂNG CHỐNG ĂN MÒN CỦA LỚP PHỦ BIẾN TÍNH CROMAT TRÊN NHÔM VỚI SỰ CÓ MẶT CỦA KMnO4
Authors: Phượng Phạm Thị
Published: April 2018

Trong bài báo này, các yếu tố như thời gian, thành phần của dung dịch cromat hóa cải tiến chứa KMnO4  sử dụng cho nhôm ảnh hưởng tới các tính chất của màng thụ động đã được nghiên cứu, khảo sát. Thành phần và cấu trúc bề mặt của lớp cromat hóa được xác định bởi phương pháp chụp ảnh hiển vi điện tử quét (SEM) và phân tích phổ phân tán năng lượng tia X (EDS). Khả năng chống ăn mòn của lớp cromat trên nền nhôm đã được nghiên cứu bằng cách phương pháp đo dòng ăn mòn Tafel và phương pháp đo tổng trở điện hóa. Các kết quả thu được cho thấy rằng KMnO4 đã tham gia vào sự hình thành của cấu trúc màng thụ động, nồng độ và thời gian có ảnh hướng tới chất lượng màng. Tăng thời gian thụ động hoặc tăng nồng độ KMnO4 độ dày màng tăng, kết quả là màng có kết cấu chặt chẽ, nhưng sự gia tăng quá mức trong thời gian thụ động làm tan màng trở lại. Các hệ số bảo vệ chống ăn mòn của lớp phủ cromat là 96,94 % đến 99,88 % tùy thuộc vào thời gian thụ động và nồng độ của KMnO4 trong dung dịch cromat. Hệ số bảo vệ chống ăn mòn đạt giá trị tối đa ở nồng độ KMnO4 0,8 g/l và thời gian thụ động của 40 giây. Kết quả phân tích tổng trở cho thấy rằng màng cromat được hình thành trên bề mặt nhôm không làm thay đổi điện trở chuyển điện tích lớp màng. Tuy nhiên màng cromat ngăn cản sự khuếch tán của các ion xuyên qua bề mặt màng do đó làm giảm sự ăn mòn của vật liệu.
pH/TEMPERATURE SENSITIVE PENTABLOCK BASED ON D,L-SERINE
Authors: Huynh Dai Phu
Published: April 2018

For recent decades, researchers have been increasing their attention to pH/temperature-sensitive polymers as drug/protein delivery systems. In this research, we aim to synthesize a new pH/temperature sensitive pentablock based on D,L-Serine. Amino groups of D,L-Serine were modified with benzenesulfonyl chloride in order to create sulfonamide groups as desired pH-sensitive groups. Pentablocks were then synthesized by conjugation reaction between carboxylic, hydroxyl groups of D,L-Serine and hydroxyl-terminal groups of temperature sensitive triblock PCL-PEG-PCL. The synthesized products were analyzed by 1H-NMR and their molecular weights were measured by gel permeation chromatography (GPC). The sol-gel transition of pentablock was also investigated by the inverting test method. The pH dependent property of the pH sensitive moiety could be very useful for preparing drug carriers.
SIMULATION STUDIES ON CHIP FORMATION PROCESS IN HIGH SPEED MILLING OF ALUMINIUM ALLOY
Authors: Hoa Pham Thi
Published: April 2018

Simulations of chip formulation mechanism and phenomenon ccurred in cutting processes can help to reduce time and cost comparing with experiment. Finite element method (FEM) is an effective and accurate technique, which can be used for simulation of cutting process. In this paper, chip formulation process in high-speed milling of A6061 aluminium alloy is investigated using FEM based on the Johnson-Cook (J-C) and Bao-Wierzbicki (B-W) fracture models. The Von-Mises stress distribution and equivalent plastic strain (PEEQ) during cutting are then investigated. Finally, the evolution of cutting forces in cutting was examined. The presented Finite element model in this study proved to be useful in determination of cutting parameters, especially in high-speed machining.
THE MAIN CHARACTERISTICS OF POCERLAIN PRODUCTS BASED ON ANORTHITE CAS2
Authors: Uyen Nhi Nguyen Vu
Published: April 2018

It is very difficult to synthesize pure CAS2 because of high melting temperature (1553 oC) In this paper, the formation of CAS2 during sintering period from the raw materials of kaolin, wollastonite, feldspar, sand and alumina at 1250 oC with holding time of 10 and 30 minutes is studied. The change during heating process was studied by the differential thermal analysis (DSC - TG). CAS2 minerals was analyzed by means of Rőntghen diffraction analysis (XRD) and phase idenfitication was performed by X'Pert High Score Plus software. The micro structure of the products has been studied through microscope images of scanning electron microscopy (SEM). The results showed that the water absorption of the products was less than 0.006 %, flexural strength reached 71-122 MPa, the Vicker’s hardness was in range from 2369 to 2666 MPa, the density was in range 2.36 – 2.59 g/cm3, the whiteness was in the range L* = 91.27 to 91.89 (according to CIELAB whiteness scale).
TỔNG HỢP VÀ TÍNH CHẤT QUANG CỦA BỘT HUỲNH QUANG PHÁT XẠ ÁNH SÁNG MÀU ĐỎ/VÀNG-LỤC VÀ LAM xCaO.MgO.2SiO2:Eu3+/Eu2+ CHO WLED
Authors: Hảo Tâm Tống Thị
Published: April 2018

Với mục đích nghiên cứu chế tạo ra loại vật liệu huỳnh quang có sự ổn định hóa học và độ bền nhiệt cao, có thể ứng dụng cho chế tạo WLED trong nước, chúng tôi đã tiến hành nghiên cứu chế tạo vật liệu xCaO.MgO.2SiO2:Eu bằng phương pháp đồng kết tủa đi từ các nguồn vật liệu ban đầu là các muối nitơrat. Đây là một loại bột huỳnh quang mới với thành phần mạng nền gồm hai pha, pha Ca2MgSi2O7(xCaO.MgO.2SiO2, x = 2) và pha Ca3MgSi2O8(xCaO.MgO.2SiO2, x = 3).Trong bài viết này chúng tôi đi sâu vào trình bày các kết quả nghiên cứu của mình về tính chất quang của vật liệu bột huỳnh quangxCaO.MgO.2SiO2:Eu3+/Eu2+ (x = 2, 3). Eu3+ pha tạp vào mạng nền xCaO.MgO.2SiO2, dưới kích thích ở bước sóng tử ngoại, sẽ cho phát xạ vùng ánh sáng đỏ, trong đó đỉnh phát xạ tại 613 nm có cường độ mạnh nhất.Eu2+pha tạp vào mạng nền xCaO.MgO.2SiO2 (x = 2, 3), dưới kích thích ở bước sóng tử ngoại, sẽ cho phát xạ vùng ánh sáng màu vàng-lục (530 nm) và vùng ánh sáng màu lam (450 nm) với cường độ phát xạ tương đương khi kích thích bởi đèn Xe bước sóng 370 nm. Nồng độ tạp Eu2+ tối ưu  pha vào mạng nền cỡ 5 %mol. Với tính chất quang như trên, bột huỳnh quang xCaO.MgO.2SiO2:Eu mà chúng tôi chế tạo dự đoán có thể kết hợp tốt với UV LED hoặc BLUE LED để tạo ra WLED.
ARBUSCULAR MICORRHIZAL FUNGI ASSOCIATION IN TWO COFFEE FARMS WITH DIFFERENT CULTIVATION AT LAM DONG
Authors: Quyen Dang Hoang
Published: April 2018

Arbuscular mycorrhizal fungi (AMF) have an important role in agriculture because of the benefits on plant and ecosystem. However, mycorrhizal association is affected by many factors such as vegetation and farming conditions. In this study, AMF system on soil and roots of coffee were investigated from two coffee farms with different cultivation method in Lam Dong Province, one was not applied fertilizer in 4 years and the other was conventional. The density, the type of mycorrhizal spore and fungal infection rate on coffee roots are different between two coffee farms. Based on morphology, there are 119 types of AMF spore in both coffee farms and most of them belongs to genera Acaulospora, Gigaspora, Entrophospora and Glomus. Spore types RE7, W6 and W1 belonged to Acaulospora and Y5 belonged to Entrophospora appeared in both farms. Besides, spore types B7, RE10, Yc, RE1 and Y1 were recorded in high density (1-4 spores /g soil). All of them were the potential strains for developing the VAM fertilizer specialized to coffee plantation.
SECONDARY METABOLITES FROM A MARINE-DERIVED FUNGUS Penicillium chrysogenum 045-357-2
Authors: Hoai Trinh Phan Thi
Published: April 2018

Marine fungi represent a potential source for natural products in the future due to the incredible diversity of chemical compounds. In our previous investigation to search new antimicrobial agents from marine-derived fungi, we isolated fungal strain Penicillium chrysogenum 045-357-2 from a soft coral sample collected from Ca Na Bay, Ninh Thuan, Vietnam. The fungus showed high antibacterial activity and was selected for further study. By various chromatography separations, two compounds including andrastinA (1) and citreohybridonol (2) were obtained from the ethyl acetate extract of culture medium of this strain. Their chemical structures were determined by analysis of 1D and 2D NMR spectra and high-resolution mass spectroscopic data, as well as by comparison of the corresponding data to those previously reported in the literature. The compound 2 exhibited antibacterial activity towards Bacillus cereus ATCC 11778 and Streptoccocus faecalis ATCC 19433 with Minimal Inhibitory Concentration (MIC) values of 32 and 64 μg/ml, respectively; however, antibacterial activity was not detected in the compound 1. This is the first report on these compounds of marine fungal strain P. chrysogenum isolated in Vietnam.
PROMOTING ASPECT OF PALLADIUM NANOPARTICLES ON SPINEL Pd@CuCr2O4/γ–Al2O3 CATALYTIC SYSTEM IN CARBON MONOXIDE OXIDATION
Authors: Kien Pham Trung
Published: April 2018

In this report, the promoting aspect of Pd on the activity of spinel CuCr2O4 and Pd catalytic systems in CO oxidation is investigated. Catalysts with compositions of 10 % spinel CuCr2O4 synthesized via modified sol–gel in situ on γ–Al2O3 support and Pd nanoparticles (0.11 ÷ 0.68) % then decorated on CuCr2O4/γ–Al2O3 via impregnation method by decomposed palladium (II) acetate solution at 280 °C for 2 h. Promoting aspect of Pd nanoparticles evaluating by Temperature Program Surface Reaction (TPSR) method in temperature range of 30 ÷ 450 °C and 15 L.h–1 flow gases consist of 1 % CO, 20 % O2 and 79 % N2 on 0.100 g catalysts. The experimental results reveal that the as–prepared materials completely convert CO at temperatures below 140 °C with 0.68 % Pd compare to 300 °C without Pd in the component. CO conversion highly increases with increasing amounts of Pd, with gas hourly space velocity reached by 1500 L.h–1.g–1 that exhibits promising application of these catalytic systems in exhausts treatment containing CO at low temperatures.
SYNTHESIS OF PURE SILICA FROM RICE HUSK ASH AS AN ANTI–CAKING AGENT FOR FERTILIZER INDUSTRY IN VIETNAM
Authors: Hieu Nguyen Huu
Published: April 2018

Pure silica particles have been successfully synthesized from rice husk ash (RHA) by precipitation method. The characterization of silica was performed by X–ray diffraction, X–ray fluorescence, Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller specific surface area, and transmission electron microscopy. The characterization results show that the obtained amorphous silica was 99.8 % purity with average particle size of 5–10 nm, and high specific surface area of 224 m2/g. Additionally, for the first time that RHA–silica was successfully applied as an anti–caking agent for a NPK–fertilizer. A suitable content of silica was evaluated through the level of anti–caking. The testing results show that with only 1.5 wt% of RHA–silica particles could replace kaolin as an anti–caking agent for the NPK–fertilizer.
EFFECTS OF SEVERAL FACTORS ON ANTI–VIBRATION ABILITY OF EPDM RUBBER
Authors: Phu Phan Quoc
Published: April 2018

In this research, ethylene–propylene–diene (EPDM) rubber, a type of synthetic rubber with excellent anti–vibration and anti–noise properties, was studied for the application in anti–vibration pads. Via changes in the concentration of substances in the mixtures such as carbon black, triethanolamine (TEA) and sulfur, the mechanical properties and the anti–vibration efficiency of the EPDM rubber samples were determined using mechanical tester. As a result, the EPDM rubber samples containing about 45 % of carbon black N330, 1 % of TEA and 1 % of sulfur showed some good results including the shore hardness about 62 A, the compressive stress at peak of 1.04 N/mm2 and the anti–vibration efficiency approximately 72 %.
EFFECT OF PREPARATION CONDITIONS OF BIOCHAR FROM RICE STRAW BY HYDROTHERMAL CARBONIZATION
Authors: Nguyen Ngoc Bich
Published: April 2018

Biochar was prepared from rice straw using hydrothermal carbonization method which consisted of zinc chloride treatment. The effects of hydrothermal temperature, time and biomass/water rate on methylene blue removal from aqueous solution were investigated. Besides, response surface modeling (RSM) and the central composite design – face centered (CCF) method will be used in designing experiments. It was found that the optimal conditions for high efficiency of biochar were such that: temperature of 194.07 °C, 9.00 hours and biomass/water ratio of 10 wt%, which resulted methylene blue removal of 92.56 %.