Search

Current filters:



Current filters:



Search Results

Results 111-120 of 205 (Search time: 0.001 seconds).
  • Authors: Vinh, Nguyen; Truong, Van; Phan, Nguyen; Hoe, Nguyen; Binh, Pham; Hung, Vu;  Advisor: -;  Co-Author: - (2022)

    In this paper, we numerically investigate the dynamics of a compound droplet driven by surface tension variation induced by a thermal gradient in a sinusoidal constriction tube. Initially, the compound droplet with a concentric inner core is spherical and placed in the constriction's upstream region with a low temperature. As time progresses, it migrates to the downstream with a high temperature. Due to the constriction, the droplet is slowed down in the upstream region and accelerated again right after passing the constriction. This acceleration maximizes the eccentricity. However, the constriction results in an increase in the maximum eccentricity when increasing its depth to a value corresponding to the size of the tube neck, which is greater than or equal to the droplet size. Ef...

  • Authors: Tran, Duc-Nghia; Phi Khanh; Phung Cong; Solanki, Vijender Kumar; Tran, Duc-Tan;  Advisor: -;  Co-Author: - (2022)

    Modern methods of monitoring help cow farmers save significantly monitoring time and improve cow health care efficiency. Behavioral changes when cows are sick may include increased or decreased daily activities such as increased lying or decreased walking time. Accelerometer advantages are low power consumption, small size, and lightweight. Thus, accelerometers have been widely used to monitor cow behavior. A cow monitoring system usually includes a central processor for receiving and processing information according to a behavioral classification algorithm through the cows’ movements. This paper introduces an effective classification system for Southern Yellow cow behavior using three degrees of freedom (3-DoF) accelerometers. The proposed classifier applied GBDT algorithm (16 seco...

  • Authors: Luan Luong, Chu;  Advisor: -;  Co-Author: - (2022)

    Terpenoids represent the largest group of secondary metabolites with variable structures and functions. Terpenoids are well known for their beneficial application in human life, such as pharmaceutical products, vitamins, hormones, anticancer drugs, cosmetics, flavors and fragrances, foods, agriculture, and biofuels. Recently, engineering microbial cells have been provided with a sustainable approach to produce terpenoids with high yields. Noticeably, the clustered regularly interspaced short palindromic repeats (CRISPR)-associated (Cas) system has emerged as one of the most efficient genome-editing technologies to engineer microorganisms for improving terpenoid production. In this review, we summarize the application of the CRISPR-Cas system for the production of terpenoids in micro...

  • Authors: D.Q.Trung; M.T.Tran; N.Tu;  Advisor: -;  Co-Author: - (2022)

    Heterostructure alloys with controlled structure and composition are essential for future electronics and optoelectronics. While heterostructure formation creates sharp electronic junction, alloying allows bandgap tunability. Herein, ZnS/ZnO heterostructure-alloy hexagonal micropyramids are grown on Si/SiO2 wafers for the first time by facile thermal evaporation of ZnS powder. It is found that the pyramids with a based size of few micrometers are grown along different crystallographic directions and neighbored by ZnS microrods. XRD and XPS spectra showed that ZnS, ZnO, and ZnSO wurtzite phases coexist in the as-received samples

  • Authors: Nguyen Van Duy; Nguyen, Xuan Thai; Trinh, Minh Ngoc;  Advisor: -;  Co-Author: - (2022)

    Classification of different gases is important, and it is possible to use different gas sensors for this purpose. Electronic noses, for example, combine separated gas sensors into an array for detecting different gases. However, the use of separated sensors in an array suffers from being bulky, high-energy consumption and complex fabrication processes. Generally, gas sensing properties, including gas selectivity, of semiconductor gas sensors are strongly dependent on their working temperature

  • Authors: Ngo, Dinh Dat; Tran, Quoc Quan; Nguyen, Dinh Duc;  Advisor: -;  Co-Author: - (2022)

    Mathematic modeling and analytical approach are presented for nonlinear vibration analysis of laminated plate with auxetic honeycomb core and magneto-electro-elastic face sheets supported by Pasternak-type elastic foundations. The laminated plate is subjected to the simultaneous action of blast, thermal, electric and magnetic loadings. The mechanical properties of auxetic core including negative Poisson’s ratio are assumed to depend on the geometrical parameters of the unit cells and elastic modulus of original material. The volume fraction of two components of each magneto-electro-elastic face sheet is chosen equally.

  • Authors: Xianyu, Jianga; Weihong, Wana; Bo, Wang;  Advisor: -;  Co-Author: - (2022)

    Magnetic absorbing materials suffer from corrosion and aging in harsh environments such as ocean and acid, which limits their practical applications. Therefore, it is important to design a material with excellent corrosion resistance and microwave absorption properties. Herein, perfluorooctyltriethoxysilane (PFOTES) modified carbonyl iron (CI) with tunable PFOTES content was prepared by the sol–gel method. The presence of PFOTES layer improved the corrosion resistance and microwave absorption of CI. The good hydrophobicity of PFOTES layer with the static contact angle of 129.73° hindered the contact of corrosive medium with CI core. The corrosion current of CI@PFOTES composite decreased significantly, and the corrosion rate was reduced by three orders of magnitude. The surface coati...

  • Authors: Trung Thanh, Nguyen; Khaled, Elbassioni; Nguyen, Cong Luong;  Advisor: -;  Co-Author: - (2022)

    In this paper, we consider a distributed joint sensing and communication (DJSC) system in which each radar sensor as a JSC node is equipped with a sensing function and a communication function. Deploying multiple JSC nodes may require a large amount of bandwidth. Therefore, we investigate the bandwidth allocation problem for the DJSC system. In particular, we aim to optimize the bandwidth allocation to the sensing function and the communication function of the JSC nodes. To improve the allocation efficiency while benefiting the spatial diversity advantage of the DJSC systems, the objective is to maximize the sum of sensing performances, i.e., estimation rates, communication performances, i.e., communication data rates, and fairness of all the users. The optimization problem is non-c...

  • Authors: Quy Van, Khuc; Duy, Nong; Tri Phu, Vu;  Advisor: -;  Co-Author: - (2022)

    This paper aims to investigate the air pollution issues in Hanoi – one of the most air polluted cities in the world in recent years – on residents’ and foreign visitors’ perceptions and how their trust in the local government to establish a joint funding mechanism to mitigate air pollution in Hanoi. Such information is fundamental in order to establish an effective and efficient program to improve air quality not only in Hanoi, but also in many cities around the world. We employ a random stratified approach coupled with the contingent valuation survey and an interval regression model over a sample of 475 residents and 75 foreigners.

  • Authors: Trung, D.Q.; Tran, M.T.; Tu, N.;  Advisor: -;  Co-Author: - (2022)

    Heterostructure alloys with controlled structure and composition are essential for future electronics and optoelectronics. While heterostructure formation creates sharp electronic junction, alloying allows bandgap tunability. Herein, ZnS/ZnO heterostructure-alloy hexagonal micropyramids are grown on Si/SiO2 wafers for the first time by facile thermal evaporation of ZnS powder. It is found that the pyramids with a based size of few micrometers are grown along different crystallographic directions and neighbored by ZnS microrods. XRD and XPS spectra showed that ZnS, ZnO, and ZnSO wurtzite phases coexist in the as-received samples. FESEM images, in situ point, and EDS elemental mapping spectra reveal that the micropyramids are composed of Zn, S, O, but each element's ratio changes with...