VNUHCM Journal of Engineering and Technology

Synthesis and evaluation of antibacterial and antifungal activities of asymmetric 2-methylimidazole-4,5-dicarboxamide derivatives containing morpholine

Phương Nguyễn Hoài Huỳnh — 2024-01-14

For several years, heterocycles have been attracted the interest of researchers due to their diverse biological activity, such as antibacterial, antifungal, antidengue properties,… Imidazole and morpholine are two heterocycles that have interesting application in potency, pharmacokinetics, pharmacodynamics… When combined in the same compound, they may generate new compounds with potential bioactivities. Imidazole-4,5-dicarboxamide (I45DC) compounds were synthesized using benzimidazole derivatives as starting material through four-step procedure: oxidation cleavage of 2-methylbenzimidazole, synthesis of pyrazinedione diacide dichloride, amidation of pyrazinedione diacide dichloride, and ring opening pyrazinedione by morpholine. The structures were determined by IR, MS, NMR spectra. The results showed that the derivatives have purity and structure consistent with expectations. Eight asymmetric I45DC compounds were synthesized, all of which were new based on Scifinder in December 2022. The yield of the reactions varies from 23 – 80%, in which the important reaction is the final one with the yield of 23 – 54% varying depending on the position of the substituents. The antibacterial, antifungal, antidengue activitives were screened on five bacterial and two fungi strains. However, they did not exhibit activity againtst tested bacteria and fungi. Nonetheless, the new I45DC compounds help to diversify synthetic compounds.

Research, experiment and comparison of single axis and dual axes solar tracking to increase solar panel power capacity

Khanh Quoc Ngo — 2023-12-31

A simulation program combined with experimental testing of three solar panel tracking systems along one axis and two dual axes will be introduced in this article. Solar panel systems are widely used today, but to achieve high performance, it is necessary to design solar panel systems that can automatically align themselves perpendicularly to the incident radiation to optimize their efficiency. Therefore, the application of solar panel tracking systems not only increases the generated electrical power but also helps improve the current state of depletion of fossil fuel resources. Based on actual measurement results and simulated data, the article demonstrates that the electrical power output of solar panels increases by 3.96% when a dual-axis tracking system is applied compared to a one-axis tracking system, and it increases by 36.8% compared to a fixed 15° tilt-angle panel, a common angle in Vietnam. Furthermore, based on the geometric angle relationships between the Sun and the inclined plane, the research team also applied a simulation program to investigate the different efficiencies of continuous tracking models throughout a year in Ho Chi Minh City, Vietnam. The results show that in August, when the Sun is at its highest position, the efficiency difference between the two models is not significant, at 3.4%. However, when the Sun is in a lower position in January, the efficiency difference is more pronounced, with the two-axis tracking system being 45.9% more efficient than the one-axis system.