Journal Articles - Natural Science - 2022

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  • Publication
    A new metaheuristic algorithm: Shrimp and Goby association search algorithm and its application for damage identification in large-scale and complex structures
    ( 2022)
    Thanh Sang-To, Hoang Le-Minh, Magd Abdel Wahab, Cuong-Le Thanh
    "largescale global optimization problems. The performance of SGA is assessed using 13 benchmark high-dimensional functions, 10 classical benchmark functions, and several real-world engineering applications. For the first time, an efficient optimization approach for structural health monitoring (SHM) in truss-like structures is presented. The proposed approach is applied for damage identification of complex structures. A real structure, namely Canton Tower in Guangzhou, China, is served as an example for damage detection. Interestingly, this tower was the tallest structure in the world in 2009 with a height of 610 m. The great merit of this example is that it provides a real complex structure with a high-dimensional problem to assess the performance of SGA in the real world. The results show that SGA can deal with this problem effectively, at the same time, it operates better to escape from local optima with faster convergence rate than population-based algorithms."
  • Publication
    Boundedness of Hardy–Ces`aro operators on variable exponent Morrey–Herz spaces
    ( 2022)
    Kieu Huu Dung, Do Lu Cong Minh, Tran Thi Nang
    In this paper, we give the necessary and sufficient conditions for the boundedness of Hardy–Ces`aro operators on some weighted function spaces such as the weighted central Morrey, weighted local central Morrey, weighted non-local central Morrey, weighted Herz and weighted Morrey–Herz type spaces with variable exponent
  • Publication
    Central composite design for the optimization of CaO and Fe2(SO4)3 facilitated transesterification of Scenedesmus sp. oil for fatty acid methyl ester production
    ( 2022)
    Kathirvel Brindhadevi
    ;
    Thangavel Mathimani
    ;
    Ramya Ganesan
    ;
    Manigandan Sekar
    ;
    Sabarathinam Shanmugam
    ;
    Tran Nhat Phuong
    ;
    Sulaiman Ali Alharbi
    ;
    Arunachalam Chinnathambi
    ;
    Usawadee Chanasut
    ;
    Kanda Whangchai
    The present research focuses on optimization of CaO and Fe2(SO4)3 facilitated transesterification conditions through central composite design (CCD) for maximal fatty acid methyl ester yield from Scenedesmus sp. At the outset, neutral lipid extraction of Scenedesmus sp. was done by Soxhlet method using hexane and it showed 13.6% neutral lipid. Conversion of neutral lipids to biodiesel was optimized using CCD and the parameters were 80 °C, 120 min reaction time, 3% CaO or Fe2(SO4)3 catalyst concentration and 6:1 methanol:oil ratio. Among the catalysts, 93% of FAME was produced at 3% CaO concentration in the above-said optimized process conditions. Biodiesel from Scenedesmus sp. oil facilitated by CaO catalyst showed 31.42% of C16:0 followed by 23.45% oleic acid and further, palmitoleic acid, linoleic acid and linolenic acid contents were at about 10.12, 10.67 and 11.92%, respectively, which signifies the use of CaO catalyst for industrial scale biodiesel production from Scenedesmus sp.
  • Publication
    Enabling Cognitive Radio in NOMA Assisted Reconfigurable Intelligent Surfaces: Outage Performance Analysis
    ( 2022)
    Nguyễn Đức Nhân
    We have derived the closed-form expressions for outage probability (OP) at both the users and compared their performance in the presence of CR networks. The results show that, in the presence of CR, the number of meta-surfaces in RIS can significantly enhance the outage performance of the users. The comparison of both users’ performance has manifested that near users will have better outage performance compared to the far users.
  • Publication
    Enhanced removal of extracellular microcystin-LR using chitosan coagulation-ultrafiltration: Performance and mechanisms
    ( 2022)
    Quang N. Tran
    ;
    Xue Jin
    ;
    Nam Q.H. Doan
    Although many studies have proposed different drinking water treatment strategies to cope with harmful algal blooms (HABs), the removal of dissolved cyanotoxins remains a technical challenge. In this study, well-controlled laboratory experiments were performed to investigate the performance of chitosan as an alternative to traditional metallic coagulants in a hybrid coagulation-ultrafiltration (UF) process for addressing multiple HABs impacts in drinking water treatment. Compared to aluminum chlorohydrate (ACH), chitosan induced the formation of much larger and compact flocs, resulting in about 50% of M. aeruginosa cells removal after simple straining. While coagulation with ACH slightly reduced the rate and extent of UF permeate flux decline, chitosan coagulation at low doses (up to 0.25 mg/L) significantly reduced membrane fouling by 33%. At optimal dose (0.25 mg/L), chitosan coagulation showed a remarkable enhancement effect on the extracellular microcystin-LR (MC-LR) removal by UF membrane, up to 50% higher than those achieved with ACH (20%) coagulation and control condition (15%). However, excessive chitosan dosing would lead to severe membrane fouling. Molecular dynamic simulation results confirmed that chitosan exhibited affinity towards MC-LR via electrostatic interactions and weaker yet prevalent hydrogen bonding. The binding between chitosan and MC-LR would lead to toxin encapsulation within the flocs structure and thus an increased level of toxin retention by UF membrane based on the mechanism of size exclusion.
  • Publication
    Influence of F− on the reduction process of Eu3+ to Eu2+ and optical properties of Eu3+/Eu2+–Er3+–Yb3+ co-doped niobate silicate glasses
    ( 2022)
    Ho Kim Dan
    ;
    Nguyen Dinh Trung
    ;
    T.H. Le
    ;
    Nguyen Le Thai
    ;
    Nguyen Minh Ty
    ;
    Dacheng Zhou
    ;
    Jianbei Qiu
    In this paper, we report the influences of F− ions on the reduction process of Eu3+ to Eu2+, and the optical properties of Eu3+/Eu2+–Er3+–Yb3+ co-doped niobate silicate glasses. The visible (VIS), upconversion (UC) emissions, and energy transfer (ET) of Eu3+/Eu2+–Er3+–Yb3+ co-doped niobate silicate glasses under the excitations of 295, 335 nm, and 980 nm laser diode (LD) were investigated. The direct/indirect optical bandgaps and CIE 1931 (x; y) chromaticity coordinates for luminescence of Eu3+/Eu2+–Er3+–Yb3+ co-doped niobate silicate glasses under the excitations of 295, 335 nm were also been calculated and identified. Remarkably, the influences of F− ions and experimental conditions platinum crucibles with the lid on enhancing the reduction process of Eu3+ to Eu2+were also investigated and discussed.
  • Publication
    Invivo detection of triacylglycerols through Nile red staining and quantification of fatty acids in hyper lipid producer Nannochloropsis sp. cultured under adequate nitrogen and deficient nitrogen condition
    ( 2022)
    Tharifkhan Shan Ahamed
    ;
    Kathirvel Brindhadevi
    ;
    Ramakrishnan Krishnan
    ;
    Tran Nhat Phuong
    ;
    Sulaiman Ali Alharbi
    ;
    Arunachalam Chinnathambi
    ;
    Thangavel Mathimani
    The green alga Nannochloropsis sp. was grown in a medium containing adequate (1.5 g/L sodium nitrate) and absence of nitrogen (0 g/L sodium nitrate) for improving the triacylglycerols (TAGs) level and fatty acid content for sustainable biodiesel production. Initially, the biomass yield of Nannochloropsis sp. was determined from the day of inoculation till 18th day and it is observed that on 14th day higher biomass yield at about 1.4 g/L was obtained. The Nile red stained cells from nitrogen sufficient and nitrogen starvation conditions observed under confocal microscopy revealed that neutral lipids exist as oil bodies were higher in nitrogen starved condition and also, the TAG content was 13.31% dryweight in nitrogen starved cells than nitrogen amended (10.46%) Nannochloropsis cells. The extracted lipids subjected for FTIR study showed the presence of TAG functional group in both condition and similarly, the FAME obtained from both condition showed the vibration at 1743 cm−1 for ester functional group. The fatty acid composition of nitrogen deplete condition revealed oleic acid methyl ester (28.7%), Behenic acid methyl ester (14.2%), cis-11, 14, 17-Eicosatrienoic acid methyl ester (8.8%) as predominant fatty acids than nitrogen supplied condition. The TAG content and FAME composition reported in this study makes Nannochloropsis sp. as plausible candidate for pilot scale biodiesel production.
  • Publication
    Judd-Ofelt analysis of Eu3+ and adjustable emission in Eu3+/Eu2+ co-doped sodium aluminosilicate glasses
    ( 2022)
    Nguyen Thi Quynh Lien
    ;
    Nguyen Ngoc Trac
    ;
    Phan Van Do
    ;
    Ho Van Tuyen
    Europium-doped sodium aluminosilicate glasses were synthesized by using the melt quenching technique. X-ray diffraction, photoluminescence spectra and luminescence decay of Eu3+ ions in glasses were investigated to estimate structural and optical properties of the prepared glasses. Phonon energies, Judd-Ofelt (JO) intensity parameters Ωλ (λ = 2, 4, 6) and radiative properties such as transition probability (A), radiative lifetime (τ), and branching ratio (βR) of Eu3+ ions in the prepared glasses were determined and Eu3+ emission may be suggested for suitable laser applications because of its high value of βR = 70.8%. The adjustable emission of Eu3+/Eu2+ from red light to blue light can be reached by heating the prepared glasses in H2 gas with various temperature and heating time. The reduction process from Eu3+ to Eu2+ ions in the glasses increases and maximum of Eu2+ emission shifts to the long wavelength with the increasing of temperature and heating time, that indicated the increase of the crystal field of sodium aluminosilicate heated in H2 gas.
  • Publication
    Judd-Ofelt analysis of Eu3+ and adjustable emission in Eu3+/Eu2+ co-doped sodium aluminosilicate glasses
    ( 2022)
    Nguyen Thi Quynh Lien
    ;
    Nguyen Ngoc Trac
    ;
    Phan Van Do
    ;
    Ho Van Tuyen
    Europium-doped sodium aluminosilicate glasses were synthesized by using the melt quenching technique. X-ray diffraction, photoluminescence spectra and luminescence decay of Eu3+ ions in glasses were investigated to estimate structural and optical properties of the prepared glasses. Phonon energies, Judd-Ofelt (JO) intensity parameters Ωλ (λ = 2, 4, 6) and radiative properties such as transition probability (A), radiative lifetime (τ), and branching ratio (βR) of Eu3+ ions in the prepared glasses were determined and Eu3+ emission may be suggested for suitable laser applications because of its high value of βR = 70.8%. The adjustable emission of Eu3+/Eu2+ from red light to blue light can be reached by heating the prepared glasses in H2 gas with various temperature and heating time. The reduction process from Eu3+ to Eu2+ ions in the glasses increases and maximum of Eu2+ emission shifts to the long wavelength with the increasing of temperature and heating time, that indicated the increase of the crystal field of sodium aluminosilicate heated in H2 gas.
  • Publication
    Luminescence properties and energy transfer processes in Ce3+-Sm3+ co-doped calcium aluminosilicate materials
    ( 2022)
    Nguyen Manh Son
    ;
    Do Thanh Tien
    ;
    Nguyen Thi Quynh Lien
    ;
    Dinh Thanh Khan
    ;
    Le Thi Thanh Hiep
    ;
    Ho Van Tuyen
    Ce3+/Sm3+ co-doped calcium aluminosilicate (CA: Ca2Al2SiO7) phosphors were successfully synthesized using the well-known method based on solid-state reaction method at elevated temperature-1280 °C. Key parameters including the structural and luminescent properties of the prepared phosphors are examined in detail via the X-ray diffraction (XRD), a scanning electron microscope (SEM) image, luminescence decay, photoluminescence and photoluminescence excitation spectra. XRD patterns indicated that the obtained phosphors reach a single phase of Ca2Al2SiO7 with tetragonal structure. Fluorescence results of CA:Ce3+ and CA:Sm3+ phosphors show the emission band of Ce3+ overlaps well the strongest excitation peak of Sm3+ lead to the energy transfer (ET) process from Ce3+ to Sm3+ when they are co-doped in CA material. In the co-doped sample CA:Ce3+,Sm3+, the Ce3+ sensitizer enriches the intense red emission of Sm3+ activator regarding the transfer of its part excitation energy to Sm3+ ions. Through analysis of luminescence behaviors, the mechanism of the ET process from Ce3+ to Sm3+ ions in CA phosphors have been determined to be the dipole-dipole interaction by applying the Dexter model. The efficiency (ηET) of energy transfer from Ce3+ ions to Sm3+ ions increase with the increase of Sm3+ concentration. The CIE coordinates of all the prepared samples were also demonstrated under different excitation wavelengths to estimate the emission feature of the prepared phosphors.
  • Publication
    Magnetic and transport behaviors of Co substitution in La0.7Sr0.3MnO3 perovskite
    ( 2022)
    L.T.T. Ngan
    ;
    N.T. Dang
    ;
    N.X. Phuc
    ;
    L.V. Bau
    ;
    N.V. Dang
    ;
    D.H. Manh
    ;
    P.H. Nam
    ;
    L.H. Nguyen
    ;
    P.T. Phong
    The magnetic and electrical properties of the substituted La0.7Sr0.3Mn1-xCoxO3 perovskite (0 ≤ x ≤ 1) were studied. Analysis of the average spin value obtained from inverse magnetic susceptibility using Curie–Weiss law for the samples suggested Co4+ ions were in the high spin state, whereas the spin state of Co3+ ions transformed from high spin to intermediate-spin state at x= 0.8. The metallic conduction behavior of the x = 0 and x = 1 samples was analyzed using the empirical equation , reflecting the importance of electron–magnon scattering effects similarly to other manganites. All the other samples displayed semiconductor-like behavior throughout the studied temperature range. The resistivity data in semiconducting La0.7Sr0.3Mn1-xCoxO3 could be fitted to the model of variable range hopping, and both hopping distance and average hopping energy reduced with increasing doped Co concentration.
  • Publication
    Mesoporous alumina: A comprehensive review on synthesis strategies, structure, and applications as support for enhanced H2 generation via CO2-CH4 reforming
    ( 2022)
    Mahadi B. Bahari
    ;
    Che Rozid Mamat
    ;
    Aishah Abdul Jalil
    ;
    Nurul Sahida Hassan
    ;
    Walid Nabgan
    ;
    Herma Dina Setiabudi
    ;
    Dai-Viet N. Vo
    ;
    Bui Thi Phuong Thuy
    Lately, the generation of hydrogen out from carbon dioxide (CO2) - methane (CH4) reforming has been touted as a feasible option for reducing two of the most harmful greenhouse gases (CO2 and CH4) in the atmosphere. However, this technology typically suffered from catalyst deactivation triggered by sintering and coke deposition. Therefore, designing a feasible catalyst by making efficient support selections is vital for overcoming this challenge. Mesoporous alumina (MA) has aroused great attraction attributed to their potential applications as catalysis supports resulted from their high surface areas combined with tunable, narrow, and uniform pore size distribution, as well as their ability to constrain active metal from sintered and deactivated during the reaction. These materials' morphology, composition, and pore structure can be directly tailored during synthesis by altering the synthesis parameters like the type of the surfactants/templates employed, pH conditions, or selection of alumina precursors. As a result, this review's major focus is on synthesizing unique MA using a range of synthesis routes and conditions. Apart from that, this review also focuses on the applications and performance of MA as catalyst support during the CO2-CH4 reforming. We believe that this effort provides the complete grasp of MA contribution towards improving the CO2-CH4 reforming activity.
  • Publication
    Some estimates for rough Hausdorff operators on the Heisenberg group
    ( 2022)
    Kieu Huu Dung, Dao Van Duong
    The purposes of this article is to establish some necessary and sufficient conditions for the boundedness of the rough Hausdorff operators on weighted Herz, central Morrey and Morrey–Herz spaces on the Heisenberg group. By applying the block decomposition method, the authors also obtain the boundedness of the rough Hausdorff operators on weighted Herz spaces for the case p 2 ð0; 1Þ.
  • Publication
    The nitrogen cycle and mitigation strategies for nitrogen loss during organic waste composting: A review
    ( 2022)
    Hong Giang Hoang
    ;
    Bui Thi Phuong Thuy
    ;
    Chitsan Lin
    ;
    Dai-Viet N. Vo
    ;
    Huu Tuan Tran
    ;
    Mahadi B. Bahari
    ;
    Van Giang Le
    ;
    Chi Thanh Vu
    Composting is a promising technology to decompose organic waste into humus-like high-quality compost, which can be used as organic fertilizer. However, greenhouse gases (N2O, CO2, CH4) and odorous emissions (H2S, NH3) are major concerns as secondary pollutants, which may pose adverse environmental and health effects. During the composting process, nitrogen cycle plays an important role to the compost quality. This review aimed to (1) summarizes the nitrogen cycle of the composting, (2) examine the operational parameters, microbial activities, functions of enzymes and genes affecting the nitrogen cycle, and (3) discuss mitigation strategies for nitrogen loss. Operational parameters such as moisture, oxygen content, temperature, C/N ratio and pH play an essential role in the nitrogen cycle, and adjusting them is the most straightforward method to reduce nitrogen loss. Also, nitrification and denitrification are the most crucial processes of the nitrogen cycle, which strongly affect microbial community dynamics. The ammonia-oxidizing bacteria or archaea (AOB/AOA) and the nitrite-oxidizing bacteria (NOB), and heterotrophic and autotrophic denitrifiers play a vital role in nitrification and denitrification with the involvement of ammonia monooxygenase (amoA) gene, nitrate reductase genes (narG), and nitrous oxide reductase (nosZ). Furthermore, adding additives such as struvite salts (MgNH4PO4·6H2O), biochar, and zeolites (clinoptilolite), and microbial inoculation, namely Bacillus cereus (ammonium strain), Pseudomonas donghuensis (nitrite strain), and Bacillus licheniformis (nitrogen fixer) can help control nitrogen loss. This review summarized critical issues of the nitrogen cycle and nitrogen loss in order to help future composting research with regard to compost quality and air pollution/odor control.
  • Publication
    The role of environmental, social, and governance responsibilities and economic development on achieving the SDGs: evidence from BRICS countries
    ( 2022)
    Vu Minh Hieu
    ;
    Nguyen Thai Hai
    The study also employed the ARDL technique to verify the association among the constructs. The findings revealed that ESG responsibilities, economic growth, net national income, FDI, and inflation positively correlate with SDG achievements in BRICS countries. This article provides help to the regulators while making policies related the SDG achievement.