Engineering Headway Vol. 25

Abstract: Urinary tract infection (UTI) is one of the most common types of infection caused by the growth of microorganisms in the human urinary tract. Nitrite, which results from nitrate degradation by microorganisms in disease, is an indicator in diagnosing UTIs. This research aims to determine the synthesis of Ag nanoparticles (AgNPs) using avocado leaf bioreductors (Persea americana Mill.) and carrageenan as a stabilizer that can be used for colorimetric detection of nitrites to minimize the use of dangerous and environmentally unfriendly inorganic materials. Characterization and analysis in this research used a UV-Vis spectrophotometer, FT-IR (Fourier Transform Infra-Red), PSA (Particle Size Analyzer), and SEM (Scanning Electron Microscopy). The AgNPs synthesis process was carried out by varying the bioreductant volume and carrageenan concentration. The optimum volume variation results were obtained at 1:1 with a maximum wavelength of 428 nm and an absorption 1.725. In addition, the optimum concentration of carrageenan was obtained at a concentration of 2.5% with a maximum wavelength of 404 nm and an absorbance of 2.582. The results obtained for AgNPs/carrageenan for colorimetric detection of nitrite showed a color change to purple with a LOD value of 0.2402 µM and LOQ of 0.8013 µM

Abstract: This research focuses on the synthesis and evaluation of the antibacterial activity of the compound cinnamylideneacetophenone, achieved through an aldol condensation reaction using cinnamaldehyde as the aromatic aldehyde and 2-acetylnaphthalene as the aromatic ketone. The primary objective of this study was to successfully synthesize cinnamylideneacetophenone and assess its antibacterial properties against specific bacterial strains. The synthesis resulted in a yield of 89.15%, and the synthesized compound was characterized using Fourier Transform Infrared Spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR) to confirm its structural integrity. Following characterization, the target compound was identified as 1-(2-naphthyl)-5-phenyl-2,4-pentadien-1-one. However, when tested for antibacterial activity using the agar diffusion method against Staphylococcus aureus and Escherichia coli, the results indicated that the synthesized chalcone analog exhibited weak antibacterial properties, with an inhibition zone diameter of less than 5 mm. In conclusion, while cinnamylideneacetophenone was successfully synthesized and characterized, its antibacterial activity was limited, suggesting further research to explore modifications that could enhance its efficacy as an antibacterial agent.

Abstract: One type of plant that thrives in Indonesia is the coffee plant. There are several types of coffee products in Indonesia, namely Arabica, Liberica, and Robusta coffee. Coffee contains caffeine compounds which if consumed in excess can affect a person's body condition. In this study, the caffeine Level of Arabica, Liberica, and Robusta coffee was measured using a linear regression equation obtained from the relationship between caffeine content and the absorbance value of a standard caffeine solution. The results of this study show that the smallest caffeine level of Arabica coffee is 0.183%, whereas the highest caffeine level of Arabica coffee is 0.867%, that the smallest caffeine level of Liberica coffee is 0.266%, whereas the highest caffeine level of Liberica coffee is 1.051%, and the smallest caffeine level of Robusta coffee is 0.589%, whereas the highest caffeine level of Robusta coffee is 1.071%. Based on regression analysis of caffeine level and the length of roasting time, it can be concluded that the longer the coffee bean roasting process, the higher the caffeine value produced.

Abstract: Abstract. Ambon banana (Musa paradisiaca) is widely consumed without its peel, which causes environmental pollution. Banana peel has a high pectin content of 22.4%, potentially as a jam product. Blueberries (Vaccinium sect. Cyanococcus) contain anthocyanin and are usually available as a natural food colorant. Therefore, the innovation of banana jam with banana peel and the addition of blueberry fruits has a high potential to give the consumer a more favorable color and taste. This study aims to get the best formulations based on the panelist's preference of the jam color, aroma, taste, texture, and overall liking of various variations of banana peel puree and blueberry fruit in banana jam with banana peel and adding blueberries. The method used in this research is a complete randomized design method with three treatments and data analysis using ANOVA Duncan alpha 5% test. This study showed the effectiveness of anthocyanin as a natural food colorant and the pectin content in the banana peel as a jam with a high shelf-life food.

Abstract: In Indonesia, students' science literacy has decreased due to the lack of innovative learning strategies carried out by teachers. Learning strategy efforts have been carried out by applying integrated ethnoscience-based problem-based learning modules to improve 21st-century skills. This research was conducted in MAN 1 Cirebon Regency using 2 classes in the form of control classes and experiments. This research instrument uses science literacy tests, observation sheets, and questionnaires. The results showed that the application of ethnoscience-based problem-based learning integrated modules was effective in improving students' science literacy skills. There was an increase in science literacy with an N-Gain value of 0.64, and there was a significant difference between the experimental class and the control class, with a 2-tailed sig value = 0.00 < 0.05. Ethnoscience can be done in addition to increasing local wisdom in the form of an introduction to batik by connecting redox material but can increase scientific literacy, especially in indicators of explaining phenomena scientifically.

Abstract: Chemical Oxygen Demand (COD) is an important factor in sewage treatment, serving as a significant indicator of the level of organic pollution in wastewater. Proper monitoring and analysis are essential to ensure the efficiency of treatment procedures. Students will be able to enhance their expertise through laboratory and pilot investigations focusing on the measurement of COD levels in sewage. Therefore, we developed a virtual laboratory that utilizes virtual reality technology to conduct the Chemical Oxygen Demand (COD) Determination experiment, which is essential for the Sewage Treatment Technology (TPL) course. This virtual laboratory utilizes the Oculus Quest 2 device. This simulation was developed for students of the Department of Industrial Chemical Engineering, Faculty of Vocational Studies, Institut Teknologi Sepuluh Nopember (ITS) Surabaya. This virtual reality experience was developed using Unity version 2019.4.21f LTS, the C# programming language, and the Unity WebXR Exporter. We then exported the application to WebXR. Although it was necessary to overcome specific challenges, this simulation provided significant benefits for functional and user testing.

Abstract: This study was conducted to determine the responses of chemistry teachers in providing chemistry experiments and managing chemistry laboratories. A purposive survey method was used in this study by giving online questionnaires through google forms. A total of 30 chemistry teachers from Jakarta area had participated in this survey and 5 of them were selected to be interviewed. The research found challenges that chemistry teachers have tried to utilize various references technology platforms in conducting learning since pandemic Covid-19 affected although the majority of them have never participated in training, the assistance from laboratory technician in managing school laboratory is still low, laboratory facilities in some schools are still not adequate, time allocation is often limited to carry out chemistry experiments in the laboratory. These challenges focus on the problem of human resources, laboratory facilities, and the content of chemistry experiments that related to time allocation. Therefore, this is the right opportunity to think about the development and implementation of chemistry laboratory information system in high schools now and in the future.