Preparation of Gold Nanoparticles, Au/Fe2O3 by Using a Co-Precipitation Method and their Catalytic Activity

Tran Thi Minh Nguyet,Nguyen Cong Trang,Nguyen Quang Huan,Nguyen Xuan,Luu Tien Hung,Masakazu Date 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.5

Au=Fe₂O₃(Au : Fe = 1 : 50) catalyst was prepared by the co-precipitation method. The co- precipitate was studied by using dierential thermal analysis (DTA) and dierential thermal gravi- metric analysis (DTGA). The structure of the sample was investigated by using X-ray diraction (XRD) and transmission electron microscopy (TEM) and high-resolution transmission electron mi- croscopy (HRTEM). The particle size was determined to be within the range of 1.5 and 8 nm. Results of the study for catalytic properties showed that T1=2 for CO and H2 oxidation were 317 and 405 K respectively. Au=Fe₂O₃(Au : Fe = 1 : 50) catalyst was prepared by the co-precipitation method. The co-precipitate was studied by using DTA and DTGA. The structure of the sample was investigated by XRD, TEM and HRTEM. The particle size was determined to be within the range of 1.5 and 8 nm. Results of the study for catalytic properties showed that T1=2 for CO and H2 oxidation were 317 and 405 K respectively. Au=Fe₂O₃(Au : Fe = 1 : 50) catalyst was prepared by the co-precipitation method. The co- precipitate was studied by using dierential thermal analysis (DTA) and dierential thermal gravi- metric analysis (DTGA). The structure of the sample was investigated by using X-ray diraction (XRD) and transmission electron microscopy (TEM) and high-resolution transmission electron mi- croscopy (HRTEM). The particle size was determined to be within the range of 1.5 and 8 nm. Results of the study for catalytic properties showed that T1=2 for CO and H2 oxidation were 317 and 405 K respectively. Au=Fe₂O₃(Au : Fe = 1 : 50) catalyst was prepared by the co-precipitation method. The co-precipitate was studied by using DTA and DTGA. The structure of the sample was investigated by XRD, TEM and HRTEM. The particle size was determined to be within the range of 1.5 and 8 nm. Results of the study for catalytic properties showed that T1=2 for CO and H2 oxidation were 317 and 405 K respectively.

Advanced Routing Algorithms and Load Balancing on MPLS

Hung, Tran Cong,Thanh, Nguyen Hoang,Thang, Nguyen Duc,Jung, Hae Won,Kim, Tae Il,Kim, Sung Hei,Yang, Woo Jin IEEE 2007 Advanced Communication Technology, The 9th Interna Vol.3 No.-

<P>In this paper, we will survey and classify researching advanced routing algorithms that take advantages of MPLS (multiprotocol label switch) network to extent routing algorithms, supporting QoS (quality of service) services and traffic engineering and load balancing. We also consider some recent projects that are researching and working with advanced routing algorithms. This paper include 6 parts. Part 1 presents introduction. Part 2 presents QoS based routing, Classification of QoS routing. Part 3 presents traffic based routing based on information of current network such as: minimum interference routing algorithm (MIRA), dynamic online routing algorithm (DORA) and based on profile information such as: profile based routing (PBR). Part 4 presents employing advanced routing algorithms part 5 presents load balancing. And last, simulation with the combination of essential packages, we build simulation environments for MPLS based on ns2, setup some advanced routing algorithms, and evaluate them with old routing protocols.</P>

The Role of Zn Doping on the Catalytic Activity of the Nanoparticle Perovskite La0.7Sr0.3MnO3

Tran Thi Minh Nguyet,Nguyen Quang Huan,Tran Que Chi,Do The Chan,Nguyen Doan Thai,Nguyen Cong Trang,Luu Tien Hung,Le Van Tiep,Nguyen Van Qui 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.5

The nanometer complex oxide La0:7Sr0.3Mn0.6Zn0.₄O₃ was prepared by using a Sol-Gel method with citric acid as a ligand. The in uence of Zn doping of La0.7Sr0.₃MnO₃ on the structure, the morphology, the surface properties and on the catalytic activity of material was studied by using X-ray diraction (XRD), transmission electron microscopy (TEM), a high-resolution images and selected area electron diraction (SAED), physical adsorption and temperature programmed surface reaction (TPSR) methods. The results showed that perovskite La0:7Sr0:3Mn0:6. Zn0.₄O₃ could well catalyse propene oxidation in the temperature range 190 { 280 ℃, which was reduced to 100 { 120 ℃ for catalyst La1-χSrχMnO₃ The nanometer complex oxide La0:7Sr0.3Mn0.6Zn0.₄O₃ was prepared by using a Sol-Gel method with citric acid as a ligand. The in uence of Zn doping of La0.7Sr0.₃MnO₃ on the structure, the morphology, the surface properties and on the catalytic activity of material was studied by using X-ray diraction (XRD), transmission electron microscopy (TEM), a high-resolution images and selected area electron diraction (SAED), physical adsorption and temperature programmed surface reaction (TPSR) methods. The results showed that perovskite La0:7Sr0:3Mn0:6. Zn0.₄O₃ could well catalyse propene oxidation in the temperature range 190 { 280 ℃, which was reduced to 100 { 120 ℃ for catalyst La1-χSrχMnO₃

Aerodynamic drag of axisymmetric models with different boattail angles under subsonic and supersonic flow conditions

The Hung Tran,Cong Truong Dao,Dinh Anh Le,Van Khiem Pham,Van Minh Do,Trang Minh Nguyen 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.12

This study examines the drag trend and flow behavior of axisymmetric models with conical boattails under subsonic and supersonic conditions by using a numerical approach. Mach numbers ranging from 0.1 to 3.0 and boattail angles varying from 0° to 24° are investigated. The numerical results are validated by experimental data under identical flow conditions. The flow behavior around the boattail body, the total drag, and the pressure distribution are analyzed in detail. The drag components acting on the boattail surface are examined to determine the reason for the change in drag due to different boattail angles and Mach number conditions. Results show that the minimum drag is around 14° for subsonic flow, but this value suddenly decreases to around 7° for supersonic flow. Formalization of the expansion and oblique shocks on the boattail is the main cause of changes in the pressure distribution on the surfaces, which in turn affect the drag trend. Moreover, the relationships among boattail angle, flow conditions, and four flow types on the boattail surface are presented in detail.

A Study on Characteristics of Power Generation System Using Biogas from the Waste of Pig Farm

Thanh-Cong Huynh,Xuan-Mai Pham,Dinh-Hung Nguyen,Minh-Tien Tran 한국수소및신에너지학회 2010 한국수소 및 신에너지학회논문집 Vol.21 No.5

electric production, a SI gasoline engine is modified to use biogas fuel and was installed in a 20 KVA power generation system. An electronic speed regulation unit is developed to keep the system speed at 1500rpm. Experimental investigations have been carried out to examine the performance characteristics of power generation system (such as: system frequency, phase output voltage,...). In addition, the operating parameters and output emissions (NOx, HC, and CO2) of biogas-fueled engine are preliminary evaluated and analyzed for the change of system load. Results indicated that the researched power generation system shows a high stability of output voltage and frequency with help of speed regulator. Biogas fuel (mainly CH4 and CO2) has an environmental impact and potential as a green alternative fuel for SI engine and they would not require significant modification of existing engine hardware. Output emissions of biogas-fueled engine are found to be relative low. NOx emission increases with the increase of output electric power of the power generation system.

Investigation of Extruded Endwall on Heat Transfer Characteristics of Channel with Staggering Pin-fins

Van-Hoang Tran,Thanh-Huan Nguyen,Frédéric Plourde,Khanh-Duy Cong Do,Duy-Hung Chung,Cong-Truong Dinh,Gia-Diem Pham 한국유체기계학회 2023 International journal of fluid machinery and syste Vol.16 No.2

In order to increase turbine efficiency while retaining structural integrity, modern jet engines need an effective cooling system. Pin-fin arrays play a significant role in the internal cooling system of the turbine blade. In examining the efficacy of cooling techniques using pin-fins, the other papers focus on pin-fin configurations. In contrast, the current study is a step toward optimizing cooling cascade endwalls for better maneuvering and reservation of vortices, which leads to more considerable heat transfer near the endwalls. This study examines the flow field and heat transfer of roughed endwall in the pin-fin channel, including varieties with flat endwall and extruded endwall. The heat transfer of the channel and pressure drop properties of the extruded endwall case are quantitatively assessed to contrast with those of the flat endwalls scenario for an intake Reynolds number range of 7400 to 36000. The leading and trailing surfaces of the channel are divided into five streamwise regions to understand better how well the pin-fins and endwalls transmit heat. The results show that the new endwall construction significantly increases the high heat transfer zones around the pin-fins compared to the flat endwall scenario. In the meantime, the heat transfer of the channel to the pin-fins is enhanced by the modified endwall configuration. The redesigned endwall outperformed the basic case regarding the HTEI, rising by 15.9%. It is found that the friction factor of the new design is increased due to the narrowing channel. However, due to their much higher heat transfer capacity, the HTEI of extruded endwall is up to 41.5% higher than the HTEI of the channel with flat endwalls. These results demonstrate that the heat transfer properties of pin-fins can be significantly improved by optimizing endwall design.

Removal of nutrients and organic pollutants from domestic wastewater treatment by sponge-based moving bed biofilm reactor

Huynh Tan Nhut,Nguyen Tri Quang Hung,Tran Cong Sac,Nguyen Huynh Khanh Bang,Tran Quang Tri,Nguyen Trung Hiep,Nguyen Minh Ky 대한환경공학회 2020 Environmental Engineering Research Vol.25 No.5

This study evaluates the efficiency of domestic wastewater treatment via Sponge-Based Moving Bed Biofilm Reactor (S-MBBR). The laboratory-based treatment plan uses polyurethane sponge with a specific surface area was 260 ㎡/㎥ as a carrier. The treatment plan operated under four different organic load rate: OLR1 = 0.4 ㎏ BOD/㎥.day; OLR2 = 0.6 ㎏ BOD/㎥.day; OLR3 = 0.8 ㎏ BOD/㎥.day; and OLR4 = 1.0 ㎏ BOD/㎥.day. During 80 d of the experiment, the highest treatment efficiency was at the organic load rate of 0.4 ㎏ BOD/㎥.day, with COD, SS, TN and TP were found to be 85.0 ± 12.9%, 85.7 ± 5.3%, 68.9 ± 1.7%, and 40.3 ± 0.2%, respectively. In which, the influent SS concentration were from 117.3 to 126.0 ㎎/L, the effluent concentration were in ranged 18.0 to 34.22 ㎎/L, respectively. The values of influent and effluent COD were 298.8 ± 12.88 and 44.8 ± 3.78 ㎎/L in turn. The OLR1 influent TN, TP concentrations were respectively 47.9 ± 2.11 and 3.6 ± 0.15 ㎎/L; the effluent TN, TP concentration were 14.9 ± 0.18 and 2.2 ± 0.06 ㎎/L, respectively. The study suggests that the effluent is within the allowable limits of National technical regulation on domestic wastewater (Column B1), indicating the applicability of S-MBBR for the domestic wastewater treatment plant.

Copper Tolerance of Novel Rhodotorula sp. Yeast Isolated from Gold Mining Ore in Gia Lai, Vietnam

Kim Cuc Thi Nguyen,Phuc Hung Truong,Cuong Tu Ho,Cong Tuan Le,Khoa Dang Tran,Tien Long Nguyen,Manh Tuan Nguyen,Phu Van Nguyen 한국균학회 2023 Mycobiology Vol.51 No.6

In this study, twenty-five yeast strains were isolated from soil samples collected in the goldmining ore in Gia Lai, Vietnam. Among them, one isolate named GL1T could highly tolerateCu2þ up to 10 mM, and the isolates could also grow in a wide range of pH (3–7), and temperature(10–40 �C). Dried biomass of GL1 was able to remove Cu2þ effectively up to 90.49%with a maximal biosorption capacity of 18.1 mg/g at pH 6, temperature 30 �C, and incubationtime 60 min. Sequence analysis of rDNA indicated this strain was closely related toRhodotorula mucilaginosa but with 1.53 and 3.46% nucleotide differences in the D1/D2domain of the 28S rRNA gene and the ITS1-5.8S rRNA gene-ITS2 region sequence, respectively. Based on phylogenetic tree analysis and the biochemical characteristics, the strainappears to be a novel Rhodotorula species, and the name Rhodotorula aurum sp. nov. is proposed. This study provides us with more information about heavy metal-tolerant yeasts andit may produce a new tool for environmental control and metal recovery operations.

Delay-Constrained Energy-Efficient Cluster-based Multi-Hop Routing in Wireless Sensor Networks

Trong-Thua Huynh,Anh-Vu Dinh-Duc,Cong-Hung Tran 한국통신학회 2016 Journal of communications and networks Vol.18 No.4

Energy efficiency is the main objective in the design of awireless sensor network (WSN). Inmany applications, sensing datamust be transmitted fromsources to a sink in a timelymanner. Thispaper describes an investigation of the trade-off between two objectivesinWSN design: minimizing energy consumption and minimizingend-to-end delay. We first propose a new distributed clusteringapproach to determining the best clusterhead for each clusterby considering both energy consumption and end-to-end delayrequirements. Next, we propose a new energy-cost function and anew end-to-end delay function for use in an inter-cluster routingalgorithm. We present a multi-hop routing algorithm for use indisseminating sensing data from clusterheads to a sink at the minimumenergy cost subject to an end-to-end delay constraint. Theresults of a simulation are consistent with our theoretical analysisresults and show that our proposed performs much better thansimilar protocols in terms of energy consumption and end-to-enddelay.

Delay-Constrained Energy-Efficient Cluster-based Multi-Hop Routing in Wireless Sensor Networks

Huynh, Trong-Thua,Dinh-Duc, Anh-Vu,Tran, Cong-Hung The Korea Institute of Information and Commucation 2016 Journal of communications and networks Vol.18 No.4

Energy efficiency is the main objective in the design of a wireless sensor network (WSN). In many applications, sensing data must be transmitted from sources to a sink in a timely manner. This paper describes an investigation of the trade-off between two objectives in WSN design: minimizing energy consumption and minimizing end-to-end delay. We first propose a new distributed clustering approach to determining the best clusterhead for each cluster by considering both energy consumption and end-to-end delay requirements. Next, we propose a new energy-cost function and a new end-to-end delay function for use in an inter-cluster routing algorithm. We present a multi-hop routing algorithm for use in disseminating sensing data from clusterheads to a sink at the minimum energy cost subject to an end-to-end delay constraint. The results of a simulation are consistent with our theoretical analysis results and show that our proposed performs much better than similar protocols in terms of energy consumption and end-to-end delay.