Abstract.A pulsed high voltage was used to remove microorganisms in drinking water. The effects of the pulsed high voltage on pH, conductivity, temperature and oxidation reduction potential (ORP) of the drinking water were investigated. The observed results show that the removal efficiency with respect to fecal coliforms and total coliforms increased with the increase of the pulsed high voltage. The removal efficiency for microorganisms such as fecal coliforms and total coliforms was in the range 25-100% and 44-100%, respectively, after the water was exposed to a pulsed high voltage of 5-10 kV for 60 minutes. An increase of the pulsed high voltage caused a decrease in the conductivity and ORP with operational time.

Polymer insulators tend to fail because of the climatic and environmental conditions. The failure occurs when the surface of insulator is contaminated by sea salt or cement dust which lead to partial discharge (PD). Leakage currents will increase by PD that causes deterioration of insulation. To predict the insulation failures, an  adaptive neurofuzzy inference system (ANFIS) method using initial color detection processes are proposed to estimate the leakage currents based on the polymer insulator thermal images (infrared signature). In this study, the sodium chloride and kaolin are used as pollutants of the polymer insulator according to IEC 60507 standards. Then, the insulator is tested in the laboratory using AC high voltage applied at 18 kV where the temperature detection is controlled at 26° C and 70% RH (relative humidity). The percentage of colors (Red, Yellow, and Blue) from the thermal image is measured using the color detection method. Correspond to the color percentage, the ANFIS method predicts leakage currents from polymer insulators. Furthermore, this system interprets measured data from insulators that need to be categorized as Safe, Need Maintenance or Harmful. The final application of the system can be a non-contact tool to predict the polymer insulators used by technicians in the field.

With the rapid development of science at this time and the criteria for recruitment of workers who need soft skills, the Teaching and Learning Process (PBM) applying the Teacher Center Learning (TCL) method is no longer appropriate. The application of the Student Center Learning (SCL), which emphasizes on the Project-Based Learning (PjBL) method is needed. The assessment is not only on hard skills (such as Tasks, Examinations, Exams, Exercises, Quizzes, group presentations, and Major Tasks) but also on soft skills. Using the SCL-PjBL method in PBM will be able to increase the maximum absorption of knowledge to students. Besides, the students must be prepared in terms of lecture material, which will be presented by more challenged lectures to be better prepared because the SCL-PjBL method makes more lecturers as facilitators. The results of the assessment of Electronics courses with the application of the SCL-PjBL method for 131 students in the 2018/2019 school year obtained an average score of soft skills of 72% from a 40% rating or 28.8 on a 100 scale.

Placing the PV in the right location will maintain the utility voltage, but if the placement of PV in the wrong location will cause the stability of the system to be affected. In this study, optimization of PV placement uses the K-means Clustering method. This method will group each node in the system from the point of view of operating characteristics LSF (loss sensitivity factor) and dV (voltage deviation). The results of grouping each bus with the K-means Clustering method will be the basis for determining the location of PV placement in the IEEE 37 and 69 bus distribution systems. In this method, grouping results are used based on the size of the proximity and have the same characteristics with each other. In determining the optimal location for PV placement, the addition of PV will reduce power losses and improve voltage. Optimal PV location placement in the IEEE 37 bus distribution system is placed on 3 buses with a power capacity of 60% where the value of power losses drops to 176.2 kW and the voltage profile is the best but there are some buses that are still under voltage and overvoltage. Meanwhile, the most optimal PV location for the IEEE 69 bus distribution system is placed on a 6 bus with a power capacity of 60% where the value of power losses drops to 149.5 kW and the voltage profile of each bus is in normal condition..

Pembangkit listrik pikotermal matahari (PLTPM) merupakan konsep awal yang masih dalam tahap kajian. Pengujian dan perhitungan tegangan dan arus listrik dilakukan terhadap termoelektrik tunggal, sel termoelektrik terhubung seri dan sel termoeletrik terhubung paralel akibat kenaikan suhu pada sel-sel tersebut. Hasil memperlihatkan bahwa kenaikan suhu sebesar 71 o C menghasilkan tegangan keluaran 1 volt dan arus 0.1 Amper. Sesuai dengan kaedah hubungan seri dan paralel, hubungan seri mampu melipat gandakan tegangan keluaran dan hubungan paralel melipatkan gandakan arus keluaran untuk tambahan setiap satu keping sel termoelektrik.