2D-model of contaminant water transmission processes and numerical simulation on a natural lake

Nowadays, the water pollution problems in the lakes are urgent matters. The simulation of contaminant water transmission process plays important role in reality to improve people's life qualities. In this paper the 2D-mathematical model simulating transmission processes of some contaminant substances in one lake of Hanoi is studied. The finite volume method is used in model. The actions between substances are considered and the simulation results are compared with the measurements

Behavior of monolithic prestressed concrete slab track at highway-railway grade crossings

Highway-railway grade crossings are an important part of the transportation system. It allows two types of vehicles to operate in the same areas. Researchers have previously studied the grade crossings, but research on the monolithic prestressed concrete slab (PSCS) track at grade crossings for 1,000mm gauge is limited. At present, there are many types of grade crossing structures that are using in Vietnam. However, these structures still have many disadvantages in the operation process. A new structure type of grade crossing for PSCS is proposed to apply for the 1,000 mm gauge to overcome the main disadvantages of existing structural types. This paper presents test production and experimental measurements to analyze the behavior of PSCS. Test samples of monolithic PSCS were produced in factory. Measurement experiments were conducted in the laboratory. The results of the manufacturing and testing process presented in this paper show that this structure completely meets the criteria of stability and durability under the effect of test loads

The Impacts of Task-Based Activities on Learners’ Grammatical Acquisition and Motivation at Dong Nai Technology University

The study aims to measure the effect of Task-based language teaching on grammatical achievement and the motivation of EFL learners at Dong Nai Technology University. The research will conduct a quick grammar test to administer 48 students at the school to achieve this goal. After sitting the test, the learners will undergo a 6-week course applying task-based language teaching. Before the treatment, one certified instructor-made grammar test about the learning units will be encompassed as the pre-test. Furthermore, a motivation questionnaire will be carried out in this group at the research's beginning and end. Afterward, the learners will learn through the treatment, which is learning through the implementation of Task-based language teaching. After six weeks of treatment, the group will take the same teacher-made grammar test as the post-test. After that, the writer will analyze the data through paired sample t-test. The results demonstrated a significant difference between the pre-test and post-test in the student’s performance on grammar acquisition and the enhancement in learners’ motivation. Based on the findings of this research, it is believed that task-based language teaching can be used in English classes to enhance learners’ grammar achievements and motivation among Vietnamese university learners

Carrageenophyte-attached and planktonic bacterial communities in two distinct bays of Vietnam: Eutrophication indicators and insights on ice-ice disease

The composition of the bacterial community of carrageenophyte-attached and planktonic bacteria was studied in two bays of Vietnam with contrasting anthropogenic inputs to assess their role as ecological indicators. Clear differences (~73% dissimilarity) between carrageenophyte-attached bacteria and bacterioplankton were detected in terms of genus composition: mainly Agaribacter, Ruegeria, Alteromonas, the Pir4 lineage and Vibrio for the carrageenophytes and Candidatus Actinomarina, HIMB 11, NS groups and SAR clades for the bacterioplankton. The copiotrophic nature, potential for complex-polymer degradation, and ability to form and defend biofilms were common features inferred for the carrageenophyte-attached microbiome. Significant differences between the bays were detected in the concentration of most inorganic nutrients. More eutrophic conditions and presumptive wastewater pollution in Cam Ranh (CR) bay were primarily indicated by the dominance of Rubripirellula, Leptobacterium, Hypnocyclicus and Porphyrobacter and their correlations with phosphate. In terms of bacterioplankton, the influence of intensive aquaculture in CR bay was suggested by the dominance of the NS5 and NS4 marine groups, the SUP05 cluster, Flavobacteriaceae unclassified and SAR 11 clade III as well as their strong correlations with ammonium and phosphate. The link between silicate and other inorganic nutrients suggests freshwater input in CR bay. Arenicellaceae unclassified and Formosa were also potential indicators of eutrophication. Operational taxonomic units (OTUs) of Marinagarivorans, Cobetia, Vibrio, Alteromonas and Pseudoalteromonas were typical of the carrageenophytes showing ice-ice disease symptoms. Vibrio and Alteromonas were also common among healthy macroalgae, and differences at the OTU level suggested potential succession of species from the healthy to the diseased state. The probable beneficial roles of some bacteria, such as Ruegeria, Cutibacterium and unidentified members of the family Rhizobiaceae, were discussed. This study provides pioneering insights into the bacterial community composition of carrageenophytes and highlights their ecological value as strong indicators of the sources of organic matter, anthropogenic impacts and health status of marine systems.Fil: Kopprio, Germán Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Leibniz - Institute of Freshwater Ecology and Inland Fisheries; Alemania. Vietnam Academy of Science and Technology. Institute of Natural Product Chemistry; VietnamFil: Cuong, Le Huu. Vietnam Academy of Science and Technology. Graduate University of Science and Technology; Vietnam. Vietnam Academy of Science and Technology. Institute of Natural Product Chemistry; VietnamFil: Luyen, Nguyen Dinh. Vietnam Academy of Science and Technology. Graduate University of Science and Technology; Vietnam. Vietnam Academy of Science and Technology. Institute of Natural Product Chemistry; VietnamFil: Duc, Tran Mai. Vietnam Academy of Science and Technology. Nhatrang Institute of Technology Research and Application; VietnamFil: Ha, Tran Hong. Vietnam Academy of Science and Technology. Graduate University of Science and Technology; VietnamFil: Huong, Le Mai. Vietnam Academy of Science and Technology. Institute of Natural Product Chemistry; Vietnam. Vietnam Academy of Science and Technology. Graduate University of Science and Technology; VietnamFil: Gärdes, Astrid. Leibniz - Institute of Freshwater Ecology and Inland Fisheries; Alemania. University of Applied Sciences; Alemania. Alfred-Wegener-Institut. Helmholtz-Zentrum für Polar und Meeresforschung; Alemani

Microfluidic Chip for Trapping Magnetic Nanoparticles and Heating in Terms of Biological Analysis

In this study, we reported the results of the design and the fabrication a planar coil in copper (square, a = 10 mm, 15mm high, 90 turns), these planar coils were integrated in a microfluidic chip for trapping magnetic nanoparticles and local heating applications. A small thermocouple (type K, 1 mm tip size) was put directly on top of the micro-channel in poly(dimethyl-siloxane) in order to measure the temperature inside the channel during applying current. The design of planar coils was based on optimizing the results of the magnetic calculation. The most suitable value of the magnetic field generated by the coil was calculated by ANSYS® software corresponded to the different distances from the coil surface to the micro-channel bottom (magnetic field strength Hmax = 825 A/m). The magnetic filed and heating relationship was balanced in order to manipulating the trapping magnetic nanoparticles and heating process. This design of the microfluidic chip can be used to develop a complex microfluidic chip using magnetic nanoparticles