This thesis presents improving power quality in power distribution system with integration of photovoltaic energy distributed generation having objectives to improve power quality in distribution system model of voltage sag and voltage swell in distribution system model of power loss in distribution system application of mathematical model model of power generation by using solar energy and distributed generation connection technique simulation. In this thesis the power flow was tested with Newton-Raphson algorithm joining with mathematical model. The case study was done by reduction of power loss in distribution system by using techniques of connection of distributed generation joining with model of distribution system 33 bus. The case study about improvement of voltage sag and voltage swell in distribution system used connection techniques of distributed generation joining with model of distribution system 69 bus. The study found that technique of connection of distributed generation that was presented could reduce power loss and showed the percentage of improvement of voltage sag and voltage swell in distribution system especially voltage sag case according to IEEE 1159-1995 standard. This thesis showed that severity level of voltage sag depended on the size and duration of each distribution system model situation by photovoltaic energy distributed generation can reduce voltage sag.

The amount of dissolved oxygen (DO) in aquaculture ponds is considered to be one of the most important aspects for the survival of fishes. The water in aquaculture ponds is stratified into distinct layers with different DO caused by differences in temperature. This temperature difference occurs when the surface layer of water heated by the sun becomes hotter than the lower water layer. Since the top layer is in contact with the air it contains the most DO. On the other hand the deepest layer is isolated from the air it contains the lowest amount of DO. This study proposed an aeration system called a Solar Circulating-Water Aeration System (SCWAS). The SCWAS uses solar thermal energy to create a natural water circulation. In other words it provides an upward current of water from the bottom to the pond surface and a downward current from the surface to the bottom. This circulation creates the movement of surface water and then increases the DO content of the surface water. This water circulation moves highly oxygenated surface water to the bottom layer forcing low oxygen water from the bottom up to the surface where it can absorb oxygen. To evaluate this design concept the numerical simulations of the system were conducted using ANSYS Fluent software. According to the simulation results the SCWAS can provide the natural water circulation. It was found that a flow rate of 2.24 L/s is obtained when the ratio between the draft tube inlet (r) the draft tube outlet (R) the base (L) is 1: 2: 3. In addition an SCWAS prototype was built and installed in a tilapia aquaculture system. A calibrated measuring system was installed to investigate the prototype performance. The experimental results indicate that the average DO values at the water surface and at the bottom of the pond increased by 1.45 and 1.40 times respectively compared with those of a pond without SCWAS. Economic analysis shows that the payback period of SCWAS is 4.58 years and its investment cost is 17.49% less than that of the paddle-wheel aerator.

This project presents an electric bicycle equipped with Solar Cell which will charge the battery with a solar panel. To be used to drive electric bicycles electric bicycles can be powered by two systems that are powered by the users cycling and from brushed DC motors from battery charging with solar panels the test will be tested by charging the panel with a time interval that the output voltage value From the solar panel which time interval is closer to the actual panel at 24 volts and charged into the batteryto test whether the electric bike can actually be used by a test drive starting with a displacement speed of 10 and 20 km/h at a distance of 100 meters. Using experiments with weight sizes of 50 60 and 70 kg respectively it was found that electric bicycles can actually be used. However the above project has been made into two parts. is the part that charges the battery from the solar panel and the second part is a separate electric bicycle.

This research aimed to study the influence of P/E ratio and market capitalization on returns of the securities in the energy sector in the Stock Exchange of Thailand. In this research the researcher has studied and collected data from the closing prices of the securities in energy sector that are currently traded in the Stock Exchange of Thailand. From January 2015 to December 2019 from the Stock Exchange of Thailand 15 companies and used descriptive analysis mean and standard deviation to test the relationship between independent variables by using correlation analysis and multiple regression analysis to determine the influence of P/E ratio and market capitalization on returns of the securities in the energy sector. The results of the research showed that the P/E ratio had a significant positive influence on returns of the energy securities in the Stock Exchange of Thailand. The market capitalization factor also found that it had no influence on returns of the energy securities in the Stock Exchange of Thailand.

The purpose of the research is to devise and implement for testing the ability to absorb energy from vibration. The results are obtained from simulating the operating status of small machines. In order to get the mechanical force from the vibrating of the machine by using piezoelectric materials (PZT) It was found that the size of the piezoelectric materials used in each condition affected the energy absorption. There are variables interested in different diameters at 27 and 35 millimeters. The result shows that the dielectric displacement is directly proportional to the force used but is inversely proportional to the size of the cross-sectional area of the piezoelectric material. In addition the ability to absorb energy in one second is 4.51 volts and has a maximum energy of 7.4 x10 -8joules.