Science, Technology, and Communication Journal

Green-synthesized ZnO and Ag nanoparticles: A comparative study of optical, morphology and structural properties for photocatalytic applications

Yanuar Hamzah — 2025-06-29

In this study, zinc oxide (ZnO) and silver (Ag) nanoparticles were synthesized using Annona muricata leaf extract as a reducing and stabilizing agent with variations in the molar ratio of 1:3, 1:5, and 1:7. Optical characterization using UV-Visible spectroscopy revealed that the variations of molar ratio influence the absorption peak and band gap energy of the resulting ZnO and Ag. UV-Vis results show that the molar ratio 1:5 was optimal for synthesizing ZnO and Ag. The band gap value of synthesized ZnO and Ag at a 1:5 molar ratio was 3.27 eV and 2.01 eV, with absorption peaks at 355 nm and 435 nm respectively. XRD characterization shows that ZnO nanoparticles has a hexagonal wurtzite structure with lattice parameters of a = 76 Å and c = 4. 95 Å and for Ag nanoparticles has a face centered cubic structure with lattice parameters a = b = c is 4.15 Å. Annona muricata leaves extract shows photocatalytic properties that can be applied to the degradation of polluted water. This shows that ZnO nanoparticles via green synthesis using Annona muricata leaf extract is a very simple, low-cost and environmentally friendly method.

Design and fabrication of chitin-derived electrodes with optimization of temperature carbonization for energy storage in supercapacitors

Rakhmawati Farma — 2025-06-29

Supercapacitors have become one of the potential solutions for efficient energy storage, and the development of carbon-based electrodes from biomass has received increasing attention due to their sustainability. This study aims to produce carbon electrodes from crab shells (CS) as biomass materials by optimizing the carbonization process with temperature variations of 600°C, 700°C, and 800°C for supercapacitor cell applications. Material characterization shows that the carbonization temperature of 700°C produces carbon electrodes with optimal semicrystalline structures and mesopore dominance, which supports efficient ion diffusion. The CS-700 carbon electrode showed the highest specific capacitance of 118.84 F/g in cyclic voltammetry tests with 1 M H₂SO₄ electrolyte. These results indicate that carbonization at 700°C provides the best electrochemical performance, making it the optimal condition for developing efficient and environmentally friendly mud crab shell biomass-based electrodes for supercapacitor cell applications.

UI/UX design thinking adoption for integrated AI point-of-sale system (Case study: Plastic Poultry Wholesale Store)

Okfalisa Okfalisa — 2025-06-29

The development of artificial intelligence (AI) technology drives the need for a point of sales (POS) system that is not only efficient, but can also provide adaptive information according to the user's sudden wishes. This research implements the design thinking method in designing a user interface (UI/UX) for a smart POS system integrated with conversational AI features. A case study was conducted at a Plastic Poultry Wholesale Store to gain in-depth insights related to field needs and operational challenges faced. The design thinking method was chosen because of its user-centered approach, through the stages of empathize, define, ideate, prototype, and testing, it is hoped that the final results obtained can be aligned with the concrete needs of users, so that the output of the system that has been designed will not be abandoned, but will always be used. In this design, the implementation of conversational AI is used to enhance the user experience through a virtual assistant feature that is able to answer dynamic questions according to the wishes of the user, so that users can freely explore any information in detail related to their overall business performance. The implementation results show that this system not only increases operational efficiency, but also improves user experience through more intuitive interactions when they want to see their business performance. This research contributes to integrating AI technology with a user-centered design approach for smart, responsive, and adaptive POS system solutions.

Argon plasma ionization in thermodynamic equilibrium with continuity equation

Anshori Kasri — 2025-06-30

Local thermodynamic equilibrium is a foundational concept in plasma physics and heat transfer, describing a state where each small region of a system can be treated as if it is in thermodynamic equilibrium, even if the whole system is not. However, achieving accurately perfect thermodynamic equilibrium conditions in real-experiments is often challenging. It often struggles for understanding phenomena like excited states or specific Arrhenius-driven reactions. As a result, the advantages of plasma modeling with simplifications can sometimes overshadow the disadvantages of experiments. This study simulated the ionization process of argon plasma using the 4th order Runge-Kutta numerical method. The simulation, initiated with initial densities before the simulation is run, each of them is electrons 2.6 × 10¹⁸ m^-3, neutral argon (Ar) 2.6 × 10¹⁸ m^-3, positive argon ions (Ar⁺) 2.6 × 10¹⁸ m^-3, and positive diatomic argon ions (Ar₂⁺) 2.6 × 10¹⁸ m^-3, successfully obtained reaction rate equilibrium data at the 625th iteration. The final densities observed were 2.46 × 10¹⁸ m^-3 for electrons, 2.27 × 10¹⁸ m^-3 for neutral argon, 6.4 × 10¹⁵ m^-3 for Ar⁺, and 4.34 × 10¹⁷ m^-3 for Ar₂⁺. These results show the equilibrium reaction rate in argon plasma which provides information that density of electron and Ar⁺ species show a decreasing trend while density of Ar and Ar₂⁺ species shows an increasing trend which are the result of ionization and recombination processes in the entire plasma system.

Analysis of bending losses in single-mode optical fiber for determining optical signal quality

Fatima Nur Ramadhani — 2025-06-30

Optical fiber is an advanced transmission medium composed of glass fibers, offering significantly higher data transfer speeds compared to conventional electrical cables. This study aims to analyze power loss resulting from bending in single-mode optical fibers (SMF) to assess the impact on optical signal quality. Five distinct SMF types were simulated using OptiFiber software at wavelengths of 1310 nm and 1550 nm, with bending radii varying from 20 – 46 mm in increments of 2 mm. The results demonstrate that power attenuation in optical fibers is affected by the wavelength of operation and bend radius. At a wavelength of 1310 nm, the highest material loss was recorded in SMF-28 at 0.0125 dB/km, whereas at 1550 nm, SMF-28 exhibited the highest material loss of 31.963 dB/km. Moreover, an increase in bending radius results in a reduction of bending losses, while a decrease in bending radius leads to a significant increase in losses. These insights contribute to the development of improved fiber optic cable designs by advocating the use of enhanced protective shielding to mitigate bending-induced signal degradation.