The UO₂ ex-ADU powder preparation and pellet sintering for optimum efficiency: experimental and modeling studies

Hung, Nguyen Trong,Thuan, Le Ba,Van Tung, Nguyen,Thuy, Nguyen Thanh,Lee, Jin-Young,Jyothi, Rajesh Kumar ELSEVIER 2017 JOURNAL OF NUCLEAR MATERIALS Vol.496 No.-

<P><B>Abstract</B></P> <P>The UO<SUB>2</SUB> nuclear fuel pellet process for light water reactors (LWR) includes the conversion of uranium hexafluoride (UF<SUB>6</SUB>) into UO<SUB>2</SUB> powder and the fabrication of UO<SUB>2</SUB> pellets from such UO<SUB>2</SUB> powder. In the paper, studies on UO<SUB>2</SUB> pellet process from ammonium diuranate-derived uranium dioxide powder (UO<SUB>2</SUB> ex-ADU powder) were reported. The UO<SUB>2</SUB> ex-ADU powders were converted from ADU at various temperatures of 973 K, 1023 K and 1073 K and then UO<SUB>2</SUB> pellets prepared from the powders were sintered at temperatures of 1923 K, 1973 K and 2023 K for times of 4 h, 6 h and 8 h. Response surface methodology (RSM) based on quadratic central composite design (CCD) type of face centered (CCF) improved by Box and Hunter was used to model the UO<SUB>2</SUB> pellet process, using MODDE 5.0 software as an assessing tool. On the base of the proposed model, the relationship between the technological parameters and density of the UO<SUB>2</SUB> pellet product was suggested to control the UO<SUB>2</SUB> ex-ADU pellet process as desired levels.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Modeling and experimental studies were made on UO<SUB>2</SUB> ex-ADU powder preparation. </LI> <LI> Time, temperature studies made on UO<SUB>2</SUB> ex-ADU powder. </LI> <LI> Parameters were optimized through modeling the UO<SUB>2</SUB> pellet processes using RSM based CCD. </LI> <LI> The quadratic mathematical model for the pellet density was determined. </LI> <LI> The proposed model was shown a good agreement with the experimental data. </LI> </UL> </P>

A New Ceanothane-Type Triterpenoid Saponin Isolated from Gouania leptostachya DC. var. tonkinensis Pit. and Its Underlying Anti-Inflammatory Effects

( Nguyen Thi Hang ),( Nguyen Thi Bich Thu ),( Le Ba Vinh ),( Nguyen Viet Phong ),( Tran Van On ),( Ki Yong Lee ) 한국미생물생명공학회 2023 Journal of microbiology and biotechnology Vol.33 No.7

Metabolites from medicinal plants continue to hold significant value in the exploration and advancement of novel pharmaceuticals. In the search for plants containing compounds with anti-inflammatory effects, we observed that the ethanol (EtOH) extract obtained from the aerial components of Gouania leptostachya DC. var. tonkinensis Pit. exhibited substantial suppression of nitric oxide (NO) in vitro. In a phytochemical study on an EtOH extract of G. leptostachya, 11 compounds were purified, including one unreported compound namely gouanioside A (1). Their chemical structures were unambiguously determined through the use of various spectroscopic techniques, such as 1 and 2D NMR, IR, and HR-ESI-MS, and by producing derivatives via chemical reactions. The EtOH extract, fractions, and a new compound exerted inflammatory effects by altering NO synthesis in murine RAW264.7 macrophage cells stimulated with lipopolysaccharide. The underlying inflammatory mechanism of the new compound 1 was also explored through various in vitro experiments. The results of this study indicate the potential usefulness of new compound 1 from G. leptostachya as a treatment for inflammatory diseases.

Spatial Interpolation and Assimilation Methods for Satellite and Ground Meteorological Data in Vietnam

( Khac Phong Do ),( Ba Tung Nguyen ),( Xuan Thanh Nguyen ),( Quang Hung Bui ),( Nguyen Le Tran ),( Thi Nhat Thanh Nguyen ),( Van Quynh Vuong ),( Huy Lai Nguyen ),( Thanh Ha Le ) 한국정보처리학회 2015 Journal of information processing systems Vol.11 No.4

This paper presents the applications of spatial interpolation and assimilation methods for satellite and ground meteorological data, including temperature, relative humidity, and precipitation in regions of Vietnam. In this work, Universal Kriging is used for spatially interpolating ground data and its interpolated results are assimilated with corresponding satellite data to anticipate better gridded data. The input meteorological data was collected from 98 ground weather stations located all over Vietnam; whereas, the satellite data consists of the MODIS Atmospheric Profiles product (MOD07), the ASTER Global Digital Elevation Map (ASTER DEM), and the Tropical Rainfall Measuring Mission (TRMM) in six years. The outputs are gridded fields of temperature, relative humidity, and precipitation. The empirical results were evaluated by using the Root mean square error (RMSE) and the mean percent error (MPE), which illustrate that Universal Kriging interpolation obtains higher accuracy than other forms of Kriging; whereas, the assimilation for precipitation gradually reduces RMSE and significantly MPE. It also reveals that the accuracy of temperature and humidity when employing assimilation that is not significantly improved because of low MODIS retrieval due to cloud contamination.

Spatial Interpolation of Meteorologic Variables in Vietnam using the Kriging Method

( Xuan Thanh Nguyen ),( Ba Tung Nguyen ),( Khac Phong Do ),( Quang Hung Bui ),( Thi Nhat Thanh Nguyen ),( Van Quynh Vuong ),( Thanh Ha Le ) 한국정보처리학회 2015 Journal of information processing systems Vol.11 No.1

This paper presents the applications of Kriging spatial interpolation methods for meteorologic variables, including temperature and relative humidity, in regions of Vietnam. Three types of interpolation methods are used, which are as follows: Ordinary Kriging, Universal Kriging, and Universal Kriging plus Digital Elevation model correction. The input meteorologic data was collected from 98 ground weather stations throughout Vietnam and the outputs were interpolated temperature and relative humidity gridded fields, along with their error maps. The experimental results showed that Universal Kriging plus the digital elevation model correction method outperformed the two other methods when applied to temperature. The interpolation effectiveness of Ordinary Kriging and Universal Kriging were almost the same when applied to both temperature and relative humidity.

Risperidone Induced DNA Methylation Changes in Dopamine Receptor and Stathmin Genes in Mice Exposed to Social Defeat Stress

Fatima Zahra Rami,Thong Ba Nguyen,Young-Eun Oh,Maryam Karamikheirabad,Thi-Hung Le,Young-Chul Chung 대한정신약물학회 2022 CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE Vol.20 No.2

Objective: Understanding complex epigenetic mechanisms is necessary to fully elucidate the effects of antipsychotic drug. This study investigated DNA methylation and mRNA expression levels of dopamine D2 and D1 receptor (Drd2 and Drd1, respectively), nuclear receptor subfamily 3, group C, member 1 (Nr3c1) and stathmin 1 (Stmn1) in brain regions of mice exposed to social defeat stress (SDS) and effects of risperidone on altered methylation and mRNA expression levels induced by SDS. Methods: Following SDS for 10 days, risperidone (0.2 mg/kg) or vehicle was administered to adult mice for 7 days. Brain tissues from the prefrontal cortex (PFC), hippocampus (HIP) and amygdala (AMY) were processed to measure methylation and mRNA levels of Drd2, Drd1, Nr3c1 and Stmn1 using pyrosequencing and real time-polymerase chain reaction. Results: We found altered methylation status of Nr3c1 and Stmn1 in the HIP and AMY of mice exposed to SDS. These changes were reversed by risperidone treatment. In addition, different methylation patterns of Drd2 and Drd1 in the PFC and AMY between defeated and control mice were identified with risperidone treatment. Conclusion: These findings suggest that risperidone can cause epigenetic changes in Drd2, Drd1, Nr3c1 and Stmn1 in defeated mice. These changes could be epigenetic mechanisms underlying antipsychotic efficacy.

Spatial Interpolation and Assimilation Methods for Satellite and Ground Meteorological Data in Vietnam

Do, Khac Phong,Nguyen, Ba Tung,Nguyen, Xuan Thanh,Bui, Quang Hung,Tran, Nguyen Le,Nguyen, Thi Nhat Thanh,Vuong, Van Quynh,Nguyen, Huy Lai,Le, Thanh Ha Korea Information Processing Society 2015 Journal of information processing systems Vol.11 No.4

This paper presents the applications of spatial interpolation and assimilation methods for satellite and ground meteorological data, including temperature, relative humidity, and precipitation in regions of Vietnam. In this work, Universal Kriging is used for spatially interpolating ground data and its interpolated results are assimilated with corresponding satellite data to anticipate better gridded data. The input meteorological data was collected from 98 ground weather stations located all over Vietnam; whereas, the satellite data consists of the MODIS Atmospheric Profiles product (MOD07), the ASTER Global Digital Elevation Map (ASTER DEM), and the Tropical Rainfall Measuring Mission (TRMM) in six years. The outputs are gridded fields of temperature, relative humidity, and precipitation. The empirical results were evaluated by using the Root mean square error (RMSE) and the mean percent error (MPE), which illustrate that Universal Kriging interpolation obtains higher accuracy than other forms of Kriging; whereas, the assimilation for precipitation gradually reduces RMSE and significantly MPE. It also reveals that the accuracy of temperature and humidity when employing assimilation that is not significantly improved because of low MODIS retrieval due to cloud contamination.

Doped Two-dimensional Semiconductor Superlattice: Photo-stimulated Quantum Thermo-magnetoelectric Effects under the Influence of a Confined Phonon

Bau Nguyen Quang,Quynh Nguyen Thi Lam,Ba Cao Thi Vi,Hung Le Thai 한국물리학회 2020 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.77 No.12

Photo-stimulated quantum thermo-magnetoelectric effects in doped two-dimensional semiconductor superlattices, including the photo-stimulated quantum Ettingshausen effect and the photo-stimulated quantum Peltier effect, have been theoretically studied by using the quantum kinetic equation method. In this work, we assume that the electron-confined acoustic phonon scattering is essential. Moreover, the presence of the laser radiation (LR) is also taken into account to determine the influence of confined phonons on the aforementioned effects. We have defined the analytical expressions for the kinetic tensors and the Ettingshausen and the Peltier coefficients, presented the numerically calculated the theoretical results for the GaAs:Si/GaAs:Be doped semiconductor superlattice and compared them with these for the case of an unconfined acoustic phonon. The results obtained indicated that the formulas for the kinetic tensors, the Ettingshausen coefficient (EC) and the Peltier coefficient (PC) contain the quantum number m specifying the confinement of a phonon and approach the results for an unconfined phonon as m goes to zero. We found that the kinetic tensors, the EC and the PC oscillate with changing magnetic field and that the confinement of a phonon causes a shift of the peaks in these oscillations to lower energy. The dependences of both EC and PC on the temperature were found to be nonlinear. Moreover, all the coefficients level off when the temperature was less than 4.5 K or greater than 5.5 K. The EC also depended on the doping concentration in a nonlinear way and reaches a positive constant value when the semiconductor superlattice was doped with a high concentration. Most of the numerical results showed that the magnitude of the tensors, the EC as well as the PC, within a confined acoustic phonon varie significantly in comparison with the unconfined phonon case. This means that the confinement of the phonon affects the thermo-magnetoelectric effect quantitatively and qualitatively. These results contribute to completing the theory of the thermo-magnetoelectric effects in the low-dimensional semiconductor systems.

Sky Mavis: Vietnam’s Unicorn that Disrupted Global Gaming Industry

Tran Diem Quynh,Do Quynh Trang,Nguyen Ha Anh,Le Ba Hung,정경화,Nguyen Phuong Linh Academy of Asian Business (AAB) 2023 Academy of Asian Business Review Vol.9 No.1

Sky Mavis, founded in 2019 by a Vietnamese software developer, is the parent of the game titled “Axie Infinity,” one of the highest-grossing blockchain-based games ever released. It took Sky Mavis only three years and eight months to transform from an idea on paper into a unicorn start-up valued at USD 8.5 billion in 2021. Sky Mavis has done an excellent job in positioning their game Axie Infinity as the pioneer, trendsetter, and revolutionary in an unestablished industry and later provided a favorable foundation for many coming applications. The success of Sky Mavis and its product, Axie Infinity, can be attributed to three main factors: product differentiation, customer-centric and community-building initiatives, and crisis management. What is special is that Sky Mavis offered players benefits beyond mere enjoyment by unleashing its potential to generate income and transfer digital assets. Successfully landing as a top player in the blockchain-based gaming market, Sky Mavis is now at the stage of choosing whether to pivot or persevere. By introducing Sky Mavis's story and analyzing its success, this article contributes to helping to understand fast-changing gaming industry and provides guidelines that can benefit game companies.