This research presents an analysis of the five-position angle in both single-axis (one-axis tracking) and dual-axis (two-axis tracking) solar tracking systems. The study compares these tracking systems, where four solar panels move simultaneously, with a fixed solar panel system. The findings revealed that the five-position angle Sun-tracking technique resulted in lower energy consumption by the tracking mechanism than in the case of an all-time solar tracking system. The key component of the implemented system is a light-dependent resistor (LDR) sensor for controlling the motion of the motor for five positions on the vertical axis and horizontal axis, processed by a microcontroller to ensure the necessary solar tracking always moves in a perpendicular direction. According to the results, the voltage, current, and power increased with both one-axis and two-axis tracking compared to those of the fixed solar panel system under the same conditions. However, when evaluating the total energy with numerical integration methods, one-axis and two-axis provided 183.12 Wh and 199.79 Wh, respectively. Consequently, the energy production of the one-axis tracking system and the one-axis tracking system was found to be 16.71% and 24.97%, respectively, when compared to the fixed-axis system. Thus, the five-position angles of the sun-tracking technique resulted in lower energy consumption than is the case of an all-time solar tracking system.

This study examines the impact of students’ anxiety, due to online learning, in different learning environments: a synchronous (Zoom) and asynchronous learning environment (YouTube) to compare students’ conceptual understanding of electric circuits. Multiple linear regression and factor analyses were conducted to examine the factor of students’ anxiety and conceptual understanding. A sample of 99 vocational students participated in the study, including YouTube (n = 49) and Zoom (n = 50) groups. The DIRECT was used to diagnose test for conceptual understanding in the electric circuits, and OTAI was used to assess anxiety in online learning test. The OTAI consists of three factors: psychological, physiological, and online. The results showed that students’ anxiety, in some factors, affected their conceptual understanding of the electric circuits in both groups. However, there was a significant increase in conceptual understanding in both treatment groups. Although the students’ conceptual understanding had a slight increase, online learning has to improve to reduce the anxiety of learners.

The lifetime of a cast-resin transformer mainly depends on the condition of insulation material. Partial discharge (PD) is an important reason for insulation deterioration in cast-resin transformers. Identifying the position of PD is very necessary for damage assessment while the transformer is still operating, and the transformer is covered by housing. This paper proposes the investigation of a cast-resin transformer using an AE sensor and HFCT sensor to specify the precise source of PD. In this study, four AE sensors were used to find PD sources, and the high-frequency current transducer (HFCT) technique was used to identify the PD source and the criteria level. The experiment, in the first two parts, identified the possibility of PD, which includes the position of PD. The final part of the experiment verified the position of the PD source of a cast-resin transformer and confirmed the inspection results. AE and HFCT sensors can be used to detect the location of PD sources, confirming the position of the PD source by sensor detection. In addition, the evident partial discharge picture on the insulator surface of high voltage side. The process successfully and accurately identifies and locates the PD source.

We investigated the use of waste glass fiber-reinforced plastic (GFRP) to remove dye from industrial wastewater. The dye adsorbent material, based on GFRP/clay ceramics, was produced by mixing crushed GFRP with clay and firing the resulting mixture. Several types of ceramics were produced by adjusting the mixing ratio of clay, crushed 40% GF/GFRP, and firing atmosphere. Adsorption tests with methylene blue (MB) dye were performed by mixing the ceramics into an MB solution while controlling the stirring speed and measuring the decrease in MB dye concentration over time. These results showed that GFRP/clay ceramics reductively fired at 1073 K had a higher MB dye adsorption ability than that of the clay ceramic. The MB dye absorptivity of the reductively fired ceramics increased as we increased the mixing ratio of GFRP. We attribute this result to the high plastic carbide content in the ceramic, which has excellent dye absorbability. Furthermore, these particles had a comparatively high specific surface area and porosity.

To utilize waste glass fiber-reinforced plastic (GFRP) and to reduce environmental pollution in rivers and lakes, we developed a filtering material that can clean contaminated water. The high strength and porous nature of glass fiber-reinforced ceramic made by mixing clay and crushed waste GFRP before firing was exploited to do so. Various specimens with different pore size distributions were made by changing the mixing ratio of clay and crushed GFRP, the GFRP particle size, and the mixture firing temperature. Bending strength and permeability tests indicated that several types of ceramics with good permeabilities and adequate bending strengths could be produced, which enables their use as filtration materials for turbid water. Filtration tests on simulated turbid water clarified the relationship between the pore size distribution and the filtering ability of the ceramic for turbid water. Filtration tests on river water verified their practical suitability as ceramic filtration materials. It is proposed that ceramics made from clay and GFRP could be used as filtering materials for turbid water.

The effective reuse of waste glass fiber-reinforced plastic (GFRP) is desired. We previously produced porous ceramics by firing mixtures of crushed GFRP and clay in a reducing atmosphere and demonstrated their applicability as adsorbents for the removal of basic dyes from dyeing wastewater. However, the primary influencing factors and the dye adsorption mechanism have not been fully elucidated, and the adsorption of acidic and direct dyes has not been clarified. In this study, adsorption tests were conducted, and the effects of the firing atmosphere, specific surface area, type of dye, and individual components were comprehensively investigated. The results showed that reductively fired ceramics containing plastic carbide residue adsorbed basic dye very well but did not adsorb acidic dye well. The clay structure was the primary factor for the dye adsorption rather than the GFRP carbide. The mechanism for the basic dye adsorption appears to have been an increase in specific surface area due to the plastic carbide residue in the ceramic structure, which increased the ion exchange between the clay minerals and the dye. By adjusting the pH of the aqueous solution, the GFRP/clay ceramic also adsorbed considerable amounts of direct dye, so the mechanism was determined to be ion exchange with the calcium component of the glass fibers.