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  • 1
    Online Resource
    Online Resource
    The Benzylation of p-Xylene Using ZnFe2O4 Nanoparticles as Heterogeneous Catalyst
    Hindawi Limited ; 2022
    In:  Journal of Nanomaterials Vol. 2022 ( 2022-4-4), p. 1-12
    Details
    In: Journal of Nanomaterials, Hindawi Limited, Vol. 2022 ( 2022-4-4), p. 1-12
    Abstract: In this paper, ZnFe2O4 nanomaterial synthesized in different solvents by hydrothermal method was used as catalyst for the benzylation of p-xylene. ZnFe2O4 catalyst was characterized by XRD, EDX, SEM and nitrogen adsorption/desorption isotherms. The influence of various parameters in the benzylation of p-xylene such as the Fe content of the prepared materials, the ratio molar of p-xylene/benzyl chloride, the catalyst dosage, and the temperature was investigated. The relationship between adsorption kinetics and reaction kinetics of p-xylene benzylation over ZnFe2O4 nanoparticles was discussed. The results indicated that ZnFe2O4 catalyst synthesized in ethylene glycol (ZFO-EG) showed high conversation for the benzylation of p-xylene. The reusability of the ZFO-EG catalyst was also investigated.
    Type of Medium: Online Resource
    ISSN: 1687-4129 , 1687-4110
    URL: Article
    DOI: 10.1155/2022/6490334
    Language: English
    Publisher: Hindawi Limited
    Publication Date: 2022
    detail.hit.zdb_id: 2229480-6
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  • 2
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    A Direct Reinforcement Learning Approach for Nonautonomous Thermoacoustic Generator
    Hindawi Limited ; 2022
    In:  Mathematical Problems in Engineering Vol. 2022 ( 2022-5-31), p. 1-11
    Details
    In: Mathematical Problems in Engineering, Hindawi Limited, Vol. 2022 ( 2022-5-31), p. 1-11
    Abstract: For nonautonomous nonlinear systems, the optimal control design is affected by the terms of partial derivative. If a reinforcement learning (RL) strategy is developed to approximate the optimal control scheme in nonautonomous nonlinear systems, then the closed control system might be unstabilizing. Therefore, in this article, the approach of direct RL law for a nonautonomous thermoacoustic generator (TAG) is investigated. We establish the mathematical model of TAG by partial differential equations (PDEs) and then transforming them into time varying nonlinear systems. The direct RL technique with Newton–Leibniz formula is implemented to consider the partial derivative term from classical policy iteration (PI) method by modifying the computation using data collection between the two sampling times. Finally, several simulation studies with some comparisons are conducted to validate the theoretical analyses.
    Type of Medium: Online Resource
    ISSN: 1563-5147 , 1024-123X
    URL: Article
    DOI: 10.1155/2022/6512906
    Language: English
    Publisher: Hindawi Limited
    Publication Date: 2022
    detail.hit.zdb_id: 2014442-8
    SSG: 11
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  • 3
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    Pilot-Scale Study of Real Domestic Textile Wastewater Treatment Using Cassia fistula Seed-Derived Coagulant
    Hindawi Limited ; 2021
    In:  Journal of Chemistry Vol. 2021 ( 2021-7-20), p. 1-8
    Details
    In: Journal of Chemistry, Hindawi Limited, Vol. 2021 ( 2021-7-20), p. 1-8
    Abstract: Plant-derived coagulants have exhibited a good potential in wastewater treatment due to their “green” characteristics, high coagulating-flocculating activity, cost-effectiveness, and biodegradability. Nevertheless, research studies have focused mainly on bench-scale experiments; pilot-scale and full-scale simulations are still limited. Herein, we firstly report a pilot-scale study of real domestic textile wastewater treatment using Cassia fistula coagulant. The material characterizations using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), and dynamic light scattering (DLS) revealed that the natural gum extracted from C. fistula seed possessed a rough and irregular surface containing a high molecular weight galactomannan. The bench-scale investigation was initially conducted to determine the optimal pollutant concentration, initial pH, and coagulant dosage in the coagulation-flocculation process. The pilot-scale study revealed that C. fistula coagulant is an effective material for real textile wastewater treatment, showing percentage removal of 93.83% at a volume of 30 L and a coagulant dosage of 1.17 mg·L−1. Coagulation-flocculation using C. fistula seed gum could be an efficient primary wastewater treatment prior to membrane or biological methods to meet Vietnamese environmental standards. The main mechanisms of textile wastewater treatment involve adsorption/bridging interactions via hydrogen bonding and electrostatic attraction between negatively charged carboxylate groups of the coagulant and positively charged pollutants.
    Type of Medium: Online Resource
    ISSN: 2090-9071 , 2090-9063
    URL: Article
    DOI: 10.1155/2021/7608856
    Language: English
    Publisher: Hindawi Limited
    Publication Date: 2021
    detail.hit.zdb_id: 2393625-3
    detail.hit.zdb_id: 2703077-5
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  • 4
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    Online Resource
    Serum and Urine Neutrophil Gelatinase-Associated Lipocalin Levels Measured at Admission Predict Progression to Chronic Kidney Disease in Sepsis-Associated Acute Kidney Injury Patients
    Hindawi Limited ; 2020
    In:  Disease Markers Vol. 2020 ( 2020-08-18), p. 1-8
    Details
    In: Disease Markers, Hindawi Limited, Vol. 2020 ( 2020-08-18), p. 1-8
    Abstract: Background . To evaluate the ratio of acute kidney injury (AKI) to chronic kidney disease (CKD) in sepsis-associated acute kidney injury (SA-AKI) patients of the intensive care unit (ICU) and predictive value of neutrophil gelatinase-associated lipocalin (NGAL) measured at the admission time in the progression of AKI to CKD. Methods . A study of 121 consecutive adult patients admitted to the intensive care unit (ICU) diagnosed as SA-AKI. AKI and CKD were defined based on Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Glomerular filtration rate (GFR) was calculated by the CKD-EPI formula. Serum and urine NGAL was measured using the BioVendor Human Lipocalin-2/NGAL ELISA with a blood sample taken at hospital admission time. Results . The ratio of AKI to CKD in SA-AKI patients was 22.3%. Mean concentration of serum and urine NGAL in AKI to the CKD group was 790.99 ng/ml and 885.72 ng/ml, higher significantly than those of recovery patients (351.86 ng/ml and 264.68 ng/ml), p 〈 0.001 . eGFR, both serum and urine NGAL had a predictive value for AKI to CKD (eGFR: AUC = 0.857 , Se = 74.1 % , Spe = 92.6 % , p 〈 0.001 . Serum NGAL: AUC = 0.868 , Se = 77.8 % , Spe = 91.5 % . Urine NGAL: AUC = 0.869 , Se = 77.8 % , Spe = 92.6 % , p 〈 0.001 . Conclusion . Serum and urine NGAL, measuring at hospital admission time, were good prognostic biomarkers of AKI to CKD in SA-AKI patients.
    Type of Medium: Online Resource
    ISSN: 0278-0240 , 1875-8630
    URL: Article
    DOI: 10.1155/2020/8883404
    Language: English
    Publisher: Hindawi Limited
    Publication Date: 2020
    detail.hit.zdb_id: 2033253-1
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  • 5
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    Online Resource
    Effects of Blanching and Drying Condition on the Quality of Small Shrimp (Acetes)
    Hindawi Limited ; 2022
    In:  Journal of Food Quality Vol. 2022 ( 2022-12-27), p. 1-9
    Details
    In: Journal of Food Quality, Hindawi Limited, Vol. 2022 ( 2022-12-27), p. 1-9
    Abstract: The study aimed to evaluate the influence of various parameters of the blanching and drying condition of small shrimp (Acetes) on some product quality parameters. Some criteria were assessed, such as salt content, astaxanthin content (ATC), and color of small shrimp. The results showed that the blanching time significantly affected the salt content. When increasing the blanching time, the salt content was found to increase from 17.35 ± 2.48 mg/g DW to 39.51 ± 0.45 mg/g DW. The astaxanthin content achieved the highest value (0.026 ± 0.001 mg/g DW) in a 2% salt solution. The study showed that the blanching and drying processes significantly affected the salt content, astaxanthin, and color of the small shrimp, and the optimized temperatures for blanching and drying were 70°C and 60°C, respectively.
    Type of Medium: Online Resource
    ISSN: 1745-4557 , 0146-9428
    URL: Article
    DOI: 10.1155/2022/3996787
    Language: English
    Publisher: Hindawi Limited
    Publication Date: 2022
    detail.hit.zdb_id: 2175284-9
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  • 6
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    Study of Seasoning Powder Processing from Gray Abalone Mushroom
    Hindawi Limited ; 2023
    In:  Journal of Food Quality Vol. 2023 ( 2023-4-25), p. 1-14
    Details
    In: Journal of Food Quality, Hindawi Limited, Vol. 2023 ( 2023-4-25), p. 1-14
    Abstract: The gray abalone mushroom is a rich source of amino acids and carbohydrate compounds, with some biological activities and antioxidants. Nowadays, the variety of food additives on the market such as sodium glutamate (E621), sodium guanylate (E627), or sodium insonate (E631), could probably cause negative effects for people’s health. This study used gray abalone mushrooms to create naturally derived seasoning products without using flavor enhancers and synthetic compounds. The gray abalone mushroom was pretreated and dried at 60°C until attaining the moisture content of 〈 5%, while the biological activity and antioxidant values were kept optimal. The mixture ingredients, including 5% abalone mushroom powder, 2% baby cornstarch, and other seasoning ingredients, were uniformly ground. The based-gray abalone mushroom powder that was packed in PE with the moisture content below 3% displayed stability in terms of quality throughout 90 days. Gray abalone mushroom seasoning powder contributed to creating safe, natural products as well as improving consumers’ health.
    Type of Medium: Online Resource
    ISSN: 1745-4557 , 0146-9428
    URL: Article
    DOI: 10.1155/2023/7991830
    Language: English
    Publisher: Hindawi Limited
    Publication Date: 2023
    detail.hit.zdb_id: 2175284-9
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  • 7
    Online Resource
    Online Resource
    Hybrid Approach of Finite Element Method, Kigring Metamodel, and Multiobjective Genetic Algorithm for Computational Optimization of a Flexure Elbow Joint for Upper-Limb Assistive Device
    Hindawi Limited ; 2019
    In:  Complexity Vol. 2019 ( 2019-01-27), p. 1-13
    Details
    In: Complexity, Hindawi Limited, Vol. 2019 ( 2019-01-27), p. 1-13
    Abstract: Modeling for robotic joints is actually complex and may lead to wrong Pareto-optimal solutions. Hence, this paper develops a new hybrid approach for multiobjective optimization design of a flexure elbow joint. The joint is designed for the upper-limb assistive device for physically disable people. The optimization problem considers three design variables and two objective functions. An efficient hybrid optimization approach of central composite design (CDD), finite element method (FEM), Kigring metamodel, and multiobjective genetic algorithm (MOGA) is developed. The CDD is used to establish the number of numerical experiments. The FEM is developed to retrieve the strain energy and the reaction torque of joint. And then, the Kigring metamodel is used as a black-box to find the pseudoobjective functions. Based on pseudoobjective functions, the MOGA is applied to find the optimal solutions. Traditionally, an evolutionary optimization algorithm can only find one Pareto front. However, the proposed approach can generate 6 Pareto-optimal solutions, as near optimal candidates, which provides a good decision-maker. Based on the user’s real-work problem, one of the best optimal solutions is chosen. The results found that the optimal strain energy is about 0.0033 mJ and the optimal torque is approximately 588.94 Nm. Analysis of variance is performed to identify the significant contribution of design variables. The sensitivity analysis is then carried out to determine the effect degree of each parameter on the responses. The predictions are in a good agreement with validations. It confirms that the proposed hybrid optimization approach has an effectiveness to solve for complex optimization problems.
    Type of Medium: Online Resource
    ISSN: 1076-2787 , 1099-0526
    URL: Article
    DOI: 10.1155/2019/3231914
    Language: English
    Publisher: Hindawi Limited
    Publication Date: 2019
    detail.hit.zdb_id: 2004607-8
    SSG: 11
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  • 8
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    Online Resource
    Utilization of Macadamia Nutshell Residue for the Synthesis of Magnetic Activated Carbon toward Zinc (II) Ion Removal
    Hindawi Limited ; 2021
    In:  Advances in Materials Science and Engineering Vol. 2021 ( 2021-9-20), p. 1-10
    Details
    In: Advances in Materials Science and Engineering, Hindawi Limited, Vol. 2021 ( 2021-9-20), p. 1-10
    Abstract: In this study, macadamia nutshell residue, a prevalent leftover and green agricultural waste in Vietnam, was utilized to prepare a magnetic activated carbon adsorbent. The obtained material was characterized by its surface functionalities, elemental composition, crystalline structure, and magnetic properties. The characterization results revealed that the composite comprised Fe3O4 nanoparticles attached to the carbon matrix. The saturation magnetization (Ms) of the composite was found to be 38.2 emu g−1, indicating a convenient separation of the solid adsorbent from aqueous media using an external magnetic field. The feasibility of removing zinc (II) ion from an aqueous solution of the activated carbon/Fe3O4 (AC/Fe3O4) composite was examined. The adsorption kinetics were best explained by the Elovich model and the pseudo-second-order model. The adsorption capacity at equilibrium and the initial rate of Zn2+ adsorption determined by the pseudo-second-order model were 22.73 mg g−1 and 4.18 mg g−1 min−1, respectively. The implications of this study are that a low-cost, green, and magnetically separable material prepared by a large-scale available solid waste can be a promising adsorbent for the elimination of heavy metals.
    Type of Medium: Online Resource
    ISSN: 1687-8442 , 1687-8434
    URL: Article
    DOI: 10.1155/2021/2543197
    Language: English
    Publisher: Hindawi Limited
    Publication Date: 2021
    detail.hit.zdb_id: 2501025-6
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  • 9
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    Online Resource
    Application of an Anaerobic–Anoxic–Oxic–Oxic (AAO/O) Model to the Treatment of Real Domestic Wastewater
    Hindawi Limited ; 2022
    In:  Journal of Chemistry Vol. 2022 ( 2022-6-11), p. 1-7
    Details
    In: Journal of Chemistry, Hindawi Limited, Vol. 2022 ( 2022-6-11), p. 1-7
    Abstract: Untreated or inadequately treated domestic wastewater has adversely affected the aquatic environment and public health in many cities in Vietnam. A conventional anaerobic–anoxic–oxic (AAO) process is recognized as an easy-to-handle approach that constrains chemical use during the procedure. Herein, we improve an AAO system by adding more oxic orders in association with a biological membrane in order to increase the hydraulic retention time (HRT) of the oxic zone in the system. The investigated system was applied to the treatment of real domestic wastewater during 168 days of operation. The performance of the system reached a stable state after 60 days of operation. The removal efficiency of total nitrogen (TN), total phosphorus (TP), total suspended solids (TSS), biological oxygen demand (BOD5), and chemical oxygen demand (COD) was found to be 93.6 ± 3.0%, 91.9 ± 3.5%, 88.6 ± 1.2%, 82.6 ± 1.4%, and 71.8 ± 0.7%, respectively. After the operation process, the TN, TP, and TSS contents in the wastewater effluents met the A level in accordance with the QCVN 14-MT:2015/BTNMT regulation, and the effluents of COD and BOD5 almost satisfied the requirement, with only some points being slightly higher than the limit values. The obtained data revealed that the AAO/O system was capable of treating domestic wastewater in small and medium-sized domestic wastewater treatment facilities.
    Type of Medium: Online Resource
    ISSN: 2090-9071 , 2090-9063
    URL: Article
    DOI: 10.1155/2022/9456026
    Language: English
    Publisher: Hindawi Limited
    Publication Date: 2022
    detail.hit.zdb_id: 2393625-3
    detail.hit.zdb_id: 2703077-5
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  • 10
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    Improving Efficacy of Endoscopic Diagnosis of Early Gastric Cancer: Gaps to Overcome from the Real-World Practice in Vietnam
    Hindawi Limited ; 2020
    In:  BioMed Research International Vol. 2020 ( 2020-04-27), p. 1-7
    Details
    In: BioMed Research International, Hindawi Limited, Vol. 2020 ( 2020-04-27), p. 1-7
    Abstract: Objective . To identify factors associated with increased proportion of early gastric cancer to total detected gastric cancer among patients undergoing diagnostic esophagogastroduodenoscopy. Methods . A nationwide survey was conducted across 6 central-type and 6 municipal-type Vietnamese hospitals. A questionnaire regarding annual esophagogastroduodenoscopy volume, esophagogastroduodenoscopy preparation, the use of image-enhanced endoscopy, and number of gastric cancer diagnosed in 2018 was sent to each hospital. Results . The total proportion of early gastric cancer was 4.0% (115/2857). Routine preparation with simethicone and the use of image-enhanced endoscopy were associated with higher proportion of early gastric cancer (OR 1.9, 95% CI: 1.1–3.2, p = 0.016 ; OR 2.7, 95% CI: 1.8–4.0, p 〈 0.001 , respectively). Esophagogastroduodenoscopies performed at central-type hospitals were associated with higher proportion of early gastric cancer (OR 1.9, 95% CI: 1.1–3.2, p = 0.017 ). Esophagogastroduodenoscopies performed at hospitals with an annual volume of 30.000–60.000 were associated with higher proportion of early gastric cancer than those performed at hospitals with an annual volume of 10.000- 〈 30.000 (OR 2.7, 95% CI: 1.6–4.8, p 〈 0.001 ) and with a volume of 〉 60.000–100.000 (OR 2.7, 95% CI: 1.7–4.2, p 〈 0.001 ). Only four (33.3%) hospitals reported all endoscopic types of early gastric cancer. Conclusions . The detection of early gastric cancer is still challenging even for endoscopists working in regions with relatively high prevalence. The real-world evidence showed that endoscopic detection of early gastric cancer could potentially improve with simple adjustments of esophagogastroduodenoscopy protocols.
    Type of Medium: Online Resource
    ISSN: 2314-6133 , 2314-6141
    URL: Article
    DOI: 10.1155/2020/7239075
    Language: English
    Publisher: Hindawi Limited
    Publication Date: 2020
    detail.hit.zdb_id: 2698540-8
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