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PENGEMBANGAN KARAKTERISTIK OPTIS PADA LARUTAN PERAK KOLOID MENGGUNAKAN METODE ELEKTRO-OPTIS Tiwiyaningsih, Tiwiyaningsih; Rahmawati, Aidah; Nurhasanah, Wahidatun Dewi; Richardina, Very; Khumaeni, Ali; Firdausi, Ketut Sofjan; Sugito, Heri; Soesanto, Qidir Maulana Binu; Azam, Much
BERKALA FISIKA Vol 23, No 1 (2020): Berkala Fisika
Publisher : BERKALA FISIKA

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (244.635 KB)

Abstract

In this paper we present a new development of optical properties on colloidal silver solutions using electro-optics effect. Samples of silver nanoparticles (NPP) were obtained by ablation method and then diluted in water to obtain various concentrations. To obtain optical characteristics of colloidal silver solutions through the electro-optical effect, the changes in the polarization of light was measured as the sample was applied by high external potential difference. The light source used was laser pointer with  = 650 nm. The results show that the colloidal silver solution shows non-linear active optical properties with increasing concentration and at a concentration of 4.6 ppm maximum natural polarization occurs. In the case of electro-optics, a voltage increase results in electro-optical contributions which correspond to the effects of non-linear polarization due to high electric fields. However, at 8 kV the maximum polarization appears also at a concentration of 4.6 ppm, which is the same as the natural polarization at that concentration. The study of colloidal silver solutions is very interesting to be further developed by electro-optical methods, because challenges and unanswered phenomena can contribute or alternative perspectives in understanding the interaction of light with matter, especially colloidal silver solutions, and the like.
Characterization of Optical Properties of Colloidal Gold Solution based on Changes in Concentration using Light Polarization Method Winarno, Winarno; Firdausi, Ketut Sofjan; Soesanto, Qidir Maulana Binu; Khumaeni, Ali
Journal of Physics and Its Applications Vol 6, No 2 (2024): May 2024
Publisher : Diponegoro University Semarang Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/jpa.v6i2.22406

Abstract

This research was conducted to determine the effect of concentration on the characteristics of changes in the polarization angle of colloidal gold solutions. The method used in this research is natural polarization. The light source used was a green laser with a wavelength of 532 nm. The colloidal gold solution was obtained using the laser ablation method and then dissolved in aquabidest. The characteristics of changes in the angle of light polarization in the gold colloidal solution were obtained by varying the concentration of the gold colloidal solution (40 ppm, 30 ppm, 20 ppm, and 10 ppm). The results showed that gold colloids have optical activity because the orientation of the gold colloid molecules allows them to interact asymmetrically with linearly polarized light. In the range of concentration from 10 to 40 ppm, the polarization angle in gold colloids shows a linear pattern as a function of concentration. Within one month the colloidal gold sample showed stable properties. This method allows us to further analyze the quality of other types of colloids using the same method. This will improve our understanding of the interaction of polarized light with nanoparticles.
A double-Gaussian wake model considering yaw misalignment Soesanto, Qidun Maulana Binu; Soesanto, Qidir Maulana Binu; Widiyanto, Puji
International Journal of Renewable Energy Development Vol 14, No 1 (2025): January 2025
Publisher : Center of Biomass & Renewable Energy (CBIORE)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.61435/ijred.2025.60690

Abstract

A wake steering has been known to effectively increase wind farm production by deflecting the upstream turbines’ wakes via yaw misalignment, thus minimizing their negative impacts on the downstream turbines' performances. This study presents analytical modeling of horizontal-axis wind turbine (HAWT) wake using low-cost analytical modeling as an alternative to expensive numerical and experimental trials. The existing double-Gaussian (DG) analytical wake model was modified to include the yaw misalignment effect, allowing its usability for the yawed HAWT wake modeling. The benchmark dataset produced by high-fidelity large eddy simulation (LES) of wake flowfields behind the turbine with yaw angles of 0º, 10º, 20º, and 30º were used to validate the accuracy of the DG yaw wake model. Overall, the DG yaw wake model predictions showed good agreement with the benchmark dataset under varying HAWT rotor yaw configurations. The analytical results verified by the LES dataset confirm the effectiveness of yaw misalignment in deflecting the wake trajectory, expediting the wake recovery downstream of the HAWT. In addition, a higher rotor yaw angle improves the wake recovery rate in the prevailing wind direction. Notable deviations against the benchmark dataset were found mainly within the near-wake region owing to flow acceleration arising from turbine-induced turbulence. As a result, the model’s predictions were slightly lower than the benchmark dataset, most likely due to neglecting the acceleration term in the analytical model derivation. Otherwise, the analytical model could accurately predict the mean wake velocity within the far-wake region for all evaluated cases, demonstrating its reliability in estimating wind speed potential within a practical distance for micrositing. These results were also proved quantitatively by statistical evaluations utilizing root mean square error (RMSE) and Pearson correlation coefficient R. The present study points out the importance of the upstream HAWTs’ rotor yaw controls to properly deflect their wakes away from their mainstream trajectories, thus effectively maximizing the wind speed potentials extracted by the downstream HAWTs and improving the overall wind farm production.
Influence of annealing on the physical and optical properties of Ge thin films deposited using thermal evaporation Hilmi, Isom; Adam, Muhammad Kevin; Purwadi, Joko; Soesanto, Qidir Maulana Binu; Kusuma, Damar Yoga
Journal of Physics and Its Applications Vol 7, No 2 (2025): May 2025
Publisher : Diponegoro University Semarang Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/jpa.v7i2.24517

Abstract

Germanium (Ge) is extensively utilized in various technological applications, particularly in optoelectronic devices due to its favorable electronic properties. In this study, Ge thin films were deposited onto soda-lime glass substrates using the thermal evaporation technique. The deposited films were subsequently subjected to annealing at temperatures ranging from 200 to 700 °C. Comprehensive characterization of the films was performed using XRD to analyze crystallinity, UV-Vis spectroscopy to evaluate optical properties, and SEM to investigate surface topography. The annealing process induced a significant phase transformation from an amorphous state to a co-existing Ge and GeO2 structures, as evidenced by XRD measurements. This structural evolution was accompanied by notable changes in the optical properties of the films. Specifically, an increase in annealing temperature resulted in a higher absorbance in the longer wavelength regions of the UV-Vis spectrum. These findings highlight the possibility of a controlled manipulation on the structural and optical characteristics of Ge thin films by thermal treatment, with potential applications in optoelectronic devices.