Journal of Technomaterial Physics

Enhancing the Crack Resistance of Polyester Resin Composites with Rice Husk Fiber Reinforcement

2025-02-04T13:57:02+07:00

Polymers have been widely developed as alternative materials to replace metal materials due to various advantages such as low density and an easy manufacturing process. Still, polymers have many disadvantages, including not having high mechanical strength, easy to crack when hit by impact. One of the materials studied is an unsaturated polyester polymer widely used for composite matrices in vehicle structural components, aircraft and ship bodies, and vehicle components. One of the studied fibers is rice husk particle fiber. The study of cracks is crucial because it causes the material to no longer be able to support the load according to the previous plan and causes failure to occur more quickly. One way to overcome material failure due to cracks in the composite material is to prevent crack propagation by adding reinforcing material. In this study, a composite material was made using rice husk fiber to increase the crack resistance of the polyester composite matrix. From the results of crack testing, there is a tendency to increase the percentage of rice husks by 5%, 10%, 15%, and 20%. The value expected to be obtained for determining the crack resistance of the material is the value of the stress intensity factor (K₁). The largest K₁ value was obtained at the variable percentage of rice husk 15% with MMA as much as 10% and MEKP 4% obtained a stress intensity factor of 1,558 MPa.m^0.5; this value can increase the value of the stress intensity factor of pure polyester K1 by 0.667 MPa.m^0.5 which shows an increase of 233.58%.

Effect of Bending Properties on the Impact Strength of Pineapple Leaf Fiber-Polyester Composites

2025-01-31T20:34:11+07:00

Raman Spectroscopic Analysis of Cu-Ag-In-S/CdSe Core/Shell Quantum Dots Grown on Mesoporous TiO2 Substrates

2025-01-31T22:56:10+07:00

This study investigates the structural and vibrational properties of Cu-Ag-In-S/CdSe core/shell quantum dots (QDs) grown on the mesoporous TiO₂ (mp-TiO₂) substrates using Raman spectroscopy and 3D Raman mapping. The Raman spectra revealed distinct vibrational modes of AgInS₂ and CdSe, compared to Cu-Ag-In-S, with a notable shift observed in the A₁ mode (282.2 cm^-1 to 260.8 cm^-1), E and B₂ modes (316.7 cm^-1 to 326.4 cm^-1), and an additional Cu-S mode (289.3 cm^-1 to 283.4 cm^-1). These shifts indicate significant interactions between the QDs and the substrate, as well as the presence of Cu and CdSe phases. 3D mapping provided spatial distribution data, showing enhanced Cu-incorporation and morphological variations across the substrates, with darker regions signifying Cu-enriched areas. The alterations in the Raman spectrum suggest a strong interaction between Cu-Ag-In-S and CdSe. The findings contribute to a deeper understanding of Cu-Ag-In-S/CdSe QDs, highlighting their potential to optoelectronic application.

Comparison of Artificial Neural Network Models for Rainfall Prediction in Palu City

2025-02-05T12:03:08+07:00

Rainfall prediction is crucial to support natural disaster mitigation and water resource management, especially in areas like Palu City with dynamic rainfall patterns. This study evaluated the performance of three Artificial Neural Network (ANN) models with different architectures to identify the most accurate model in predicting rainfall in 2023. To obtain the model, the historical data of nine meteorological parameters in Palu City from 2018 to 2022 was processed using the Python programming language through pre-processing, processing, post-processing, and verification stages. All three models obtained are designed with hidden layers and different nodes. The best model obtained was Model A with one hidden layer, 8 nodes, and a MAPE value of 9.42%, putting it in the excellent category. Meanwhile, Model B and Model C are in a suitable category with MAPE values of 14.43% and 10.23%. The challenge of using the ANN method in predicting rainfall is its tendency to equalize extreme rain. Therefore, complete data is needed to improve ANN performance.

An In-depth Study of Relation Between Band Gap Energy and Lattice Constant for Cubic Phase LiSnX3 (X = F, Cl, Br, and I) Perosvkite

2025-02-07T11:44:46+07:00

Organic perovskites or inorganic perovskites are very popular among researchers who are designing the most efficient perovskite solar cells. Besides, they can be used as materials for other optoelectronic applications, such as light-emitting diodes. In this paper, we reported the results of studies on the electronic property of LiSnX₃ (X = F, Cl, Br, or I) perovskite in the cubic phase. This electronic property is the density of states, which one can determine the band gap energy value. These studies were undertaken to understand the relation between their band gap energy and lattice constant through anion X variations. The Quantum ESPRESSO program calculated These two crucial quantities with norm-conserving Troullier-Martins pseudopotentials and Generalized Gradient Approximation Perdew-Burke-Enzerhof exchange-correlation functional. The computation results show that the band gap energy ranged from 0,3 eV to 0,99 eV while the lattice constant ranged from 6,183 Å to 4,625 Å for anion halide from I till F, respectively. The contrast trend between these quantities' values matches the Kronig-Penney Model.

Effectiveness of Ozone Plasma Technology in Enhancing the Survival of Gourami (Osphronemus goramy) Fish Eggs

2025-02-14T19:51:46+07:00

The gourami (Osphronemus goramy) fish is a freshwater fish commonly found in Asia and widely cultivated by fish farmers or local inhabitants. The survival rate of gourami fish from egg to larva and juvenile stages is very low, at approximately 50%. Several factors, such as unstable environmental conditions, poor water quality, and fungal growth on the eggs, cause this. Typically, synthetic medications or natural materials such as betel leaves and others are used to improve gourami fry's survival rate. In this study, the researchers attempted to apply ozone plasma technology dissolved in water to observe the egg hatchability of gourami fish. This study aims to apply technology in fisheries and aquatic sciences. The results of the study show that ozone technology can be applied to observe larval survival, with the highest survival rates found in the 10-minute and 15-minute ozone treatments, both achieving 100% hatchability, with larval survival rates of 86.67% and 96.66%, respectively.