Accepted manuscripts
Blueshift of the optical bandgap in ZnO films by controlling the substrate temperature
E. Nurfani, C. Chotimah, M.S. Anrokhi, G.T.M. Kadja, W.S. Sipahutar, A. Mustaqim, A. Rianjanu
Abstract: This study investigates the growth of ZnO thin films using the spray pyrolysis method, focusing on the effect of substrate temperature on the optical bandgap. By varying the deposition temperature from 300 to 500°C, we aim to understand how temperature influences the optical properties of ZnO films. The films were characterized using X-ray diffraction (XRD) and UV-visible spectroscopy (UV-Vis). At 300°C, the absorption was lowest, and the optical bandgap increased from 3.20 eV at 300°C to 3.70 eV at 500°C. These findings are crucial for developing ZnO materials for optoelectronic applications using an efficient and cost-effective deposition method.
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Turbine Slope Testing in Microhydro Plants as a Regional Electricity Source near River Flows that are not Reachable by PLN
M. Arief Bustomi, Meli Riski Utami, Bachtera Indarto, Yono Hadi Pramono,Gontjang Prajitno, Ali Yunus Rohedi, and Endah Purwanti
Abstract: Electrical energy has become the main need of society. PLN manages the supply of electrical energy in Indonesia as the State Electricity Company. The problem is that not all areas of Indonesia are covered by the PLN electricity network. Various energy sources can be converted into electrical energy in remote areas not yet reached by the PLN network. One example of this energy source is micro hydro energy, energy from river flows that are not too strong. The equipment for converting micro hydro energy into electrical energy is called MHPP. This research is part of the application of MHPP based on Archimedes screw turbines as a source of electricity for areas near river flows that are not yet accessible to river flows. The focus of the research is to study the effect of the turbine elevation angle on the output electrical power of the MHPP. This research aims to determine the optimum values of rotation, torque, voltage, current and electrical power produced by an Archimedes screw turbine MHPP design with variations in turbine elevation angles of 20°, 25°, 30°, 35° and 40°. The MHPP design studied consists of 3 blades, a gearbox ratio of 2.8:1, a water flow rate of 6.34 liters/second, and a low rpm BLDC generator type. The optimum rotation is 1001.38 rpm at an elevation angle of 35° and the optimum torque is 1,738 Nm at an elevation angle of 40°. The optimum voltage is 14.84 V, the optimum current is 0.670 A, and the optimum electrical power is 7.861 W at an inclination angle of 40°.
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Viscosity Modeling and Prediction of Amorphophallus oncophyllus and Sapindus rarak Using Machine Learning Methods
Muhammad Taufiq Fathaddin, Dwi Atty Mardiana, Andrian Sutiadi, and Fajri Maulida
Abstract: Viscosity plays an important role in regulating the mobility of fluids injected into the reservoir to increase the efficiency of oil sweeping. This study discusses the application of Machine Learning methods, namely ANN and ANFIS, to model the correlation of physical properties of Amorphophallus oncophyllus and Sapindus rarak solutions. The purpose of this study is to obtain a correlation to determine the viscosity of the polymer solutions. The data used include viscosity measurements for 21 samples of Amorphophallus oncophyllus and Sapindus rarak solutions with variations in concentration and salinity. The data is augmented by digitization for modeling. The results show that both Machine Learning methods can estimate viscosity values well. Very accurate results are achieved by applying ANN and ANFIS with average correlation coefficients of 0.997240 and 0.995124, respectively.
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