Trường Đại học Bách khoa - Đại học Quốc gia Thành phố Hồ Chí Minh

Amine-SiO2 material (basically on silicon dioxide) was synthesized by the grafting method with triamine silane to form activated amine groups on the surface of SiO2 support and was applied as a novel adsorbent for nitrate removal from aqueous solution. The characterizations of Amine-SiO2 were determined by using TGA, FTIR, BET, SEM. Nitrate adsorption capacity and durability of Amine-SiO2 were compared with the anion exchange resin (Akualite A420 commercial). The results showed that Amine-SiO2 had high nitrate adsorption capacity, ~ 1.14 fold higher than the Akualite A420 ion exchange resin, based on the adsorption efficiency. This might be due to a strong affinity for nitrate ions of the activated amine groups on the surface of SiO2 support. In addition, the experimental results also proved that Amine-SiO2 material had good durability (stable performance after 10 regeneration times).

Sustainable Urban Drainage System (SUDS) includes various drainage techniques designed to reduce the run-off flow, improve the water quality, and provide amenity or landscape features. However, selecting the appropriate SUDS technique depends on not only the technical characteristics but also the community's perception and preference. Therefore, this study aims to determine the impact factors on the probability of households' prioritization towards SUDS benefits in the context of Nhieu Loc - Thi Nghe sub-basin, including the benefits of flood reduction, environmental enhancement, and landscape improvement. Data processing methods used in this study consist of statistical tests and ordinal regression using SPSS software. The regression results show that the overall accurate prediction rate for the 3 priority levels of SUDS benefits ranges from 50% to 70%. Factors that statistically significantly influence the priority include household income, knowledge of SUDS, frequency of flooding, depth of flooding, the distance to the nearest park, the distance to the nearest water body, and the distance to the nearest flooded location. In particular, the proximity to the nearest park affects the priority choice for all SUDS benefits with the principle that households near the park will probably choose higher priority to SUDS benefits than those living further.

This paper present a modulation scheme for the Spare Matrix Converter (SMC) topology. The proposed method uses the space vector modulation (SVPWM) technique to control the converter’s rectifier stage and inverter stage. This method achieved the maximum modulation ratio of 0.866 with sinusoidal input/output current waveforms. In the other hand, a simple real-time implementation method avoiding additional CPLD or FPGA devices is introduced. This technique is verified through simulation results using PSIM software and experimental results a 32-bit floating-point DSP (TMS 320F28335).

East Sea is large about 3,447,000 km' and seashore of Vietnam is 3,200 km long. Tide is the most important element of hydrodynamics. The tide is also to impact to the most of aspects by a system of river and small irrigation of canal in coastal area deeply. This system of river and irrigation of canal is impected by tidal dynamics. So, its characteristics, properties are formed.

This study is conducted to discover the relationship between the growth ta xanh coconut fruit and lipid accumulation in its endosperm. During the fruit development period, several criteria are determined, such as the fresh and dry weight of the crustal or seed, the amount of glucose, protein and lipid in the liquid and solid endosperm. The growth period of ta xanh coconut fruit is 12 months and is divided into four stages, lasting from fruit set to harvest. Each stage lasts about three months: (1) young fruit stage, (2) the growth fruit stage, (3) the growth solid endosperm stage (coconut meat), (4) the maturation and ripening stage. In particular, the young fruit period is the slow growth period of the fruit, followed by the second stage that is marked by a rapid growth of fruit in crustal and liquid endosperm (coconut milk). At the end of this stage, the liquid endosperm not only reaches the maximum size and weight but also contains the highest level of glucose and starch. During the third stage (7th - 9th month), the volume and content (glucose and starch) of the liquid endosperm remain stable. In this stage, the solid endosperm is formed from the liquid endosperm. The final stage is that of reducing the volume of the liquid endosperm whereas the embryo and solid endosperm grow significantly. Additionally, maximum lipid accumulation occurred in both liquid and solid endosperm.

Na8TM (TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn) clusters are optimized by DFT calculations combining the Triple zeta valence plus polarization (TZVP) method to determine magnetic torque values on orbits, point groups, electron structures, and spin density images of the atomic groups. The results indicate that Na atoms in Na8TM cluster strongly affect the total magnetic moment of the whole group of atoms. In a cluster, each Na atom contributes one electron which combines with valence electron of transition metal for creating a sum of valence electron of the cluster. Atomic groups with the highest magnetic moments are Na8V (5 B) and non-magnetic clusters are Na8Ni and Na8Zn. The electronic structure and magnetic properties of the clusters resemble those of some metals and transition metal ions. This study will orientate to substitution in magnetic materials by metal clusters.

Cartogram, an impressive way of spatial data visualization, is widely used in Eastern countries. However, it has not been officially introduced nor accepted in Viet Nam. Aiming at diversifying data visualization methods, this paper presents an overview of cartogram with Vietnamdata- illustration, from which an issue of using this way of data visualization would be considered.

This study aimed to predict the intention to buy real estate for investment. It was guided by the Theory of planned behavior (TPB) and Financial Management Behavior View (FMBV). Apart from 6 in-depth interviews, a total of 253 questionnaires were completed by respondents in Da Lat City, Lam Dong Province. By mixing both quantitative and qualitative research and data, the breadth and depth of understanding about real estate buying behavior were gained, and hypotheses were tested. The results show that the extended TPB, which includes customers’ attitudes, subjective norms, perceived behavior control, and financial satisfaction, is a good model for predicting the willingness to buy real estate for investment. As a result, planned behavior and financial satisfaction played a role in the intention to buy real estate for investment in Da Lat city, Vietnam. Managerial implications were also grasped: real estate companies might pay attention to the attitude of their customers, finding out who could influence the customers’ decision-making in a real estate context, helping their customers have better understanding while buying real estate; customers’ financial satisfaction is also considerable while dealing with real estate customers.

The growth of Ta Xanh coconut fruit is divided into four stages: slow growth, rapid growth, mature and ripening. In the mature and ripening stages, lipid accumulation increased at the strongest level in the endosperm. This study was conducted with the purpose of studying the effects of plant growth regulators on the growth and lipid accumulation in copra (solid endosperm) from the mature to ripening stage in Ta Xanh coconut fruit. Fresh weight, dry weight and lipid content in solid endosperm after treatments with 1 mg/L NAA, 10 mg/L BA and 20 mg/L GA3 individually or in combination with ethrel were determined. Results showed that the treatment of 20 mg/L GA3 on the 8-month-old fruits increased the copra fresh weight and dry weight. Treatments of 1 mg/L NAA, 20 mg/l GA3 or 200-250 mg/L ethrel on the 10-month-old fruits increased the ratio of lipid in the copra of each fruit. Treatment of 200 mg/L ethrel had a positive effect on increasing of the fresh weight, dry weight and lipid concent in the solid endosperm of the 10-month-old Ta Xanh coconut after 1 or 2 weeks of combinated treatment of 1 mg/L NAA, 10 mg/L BA and 20 mg/L GA3.

Orthotropic materials are particular type of anisotropic materials; In contrast with isotropic materials, their properties depend on the direction in which they are measured. Orthotropic composite materials and their structures have been extensively used in a wide range of engineering applications. Studies on their physical behaviors under in-work loading conditions are essential. In this present, we apply an extended meshfree radial point interpolation method (XRPIM) for analyzing crack behaviour in 2D orthotropic materials models. The thin plate spline (TPS) radial basis function (RBF) is used for constructing the RPIM shape functions. Typical advantages of using RBF are the satisfaction of the Kronecker’s delta property and the high-order continuity. To calculate the stress intensity factors (SIFs), Interaction integral method with orthotropic auxiliary fields are used. Numerical examples are performed to show the accuracy of the approach; the results are compared with available refered results. Our numerical experiments have shown a very good performance of the present method.