This thesis aims to study the optimization of the supply fuel system of pipeline by improving the pumps system from use pump size 1850 kW (2 pupms) and use only control valve. We design new system by use pump size 1850 kW (2 pumps) with variable speed motors (VSD). In this way we can control stability of opening and closing of the valve at 100% and use adjusting of the frequency of VSD as follow typing of fuel. To analysing of efficiency system we will use fuel 4 type that have different coefficient of density are JET A1 Disel B91 and B95. And then we compared the relationship between the quantity of each fuel per time and usage of power for the old system and new design that we found the new design as analyze the result and as follow the theory of Affinity Law have the value of efficacy more than. And it also can save energy cost to 52.13%

The objective of this research is to study how rotation speeds affect mechanical properties with friction welding between semi-solid metal 7075 aluminum alloys and semi-solid metal 356 aluminum alloys. The factor of interest is rotation speeds with different conditions at 800 1000 1200 1400 and 1600 rpm respectively. 1.8 millimeter for burn of length 30 seconds for welding time and clockwise rotation are set as a control constant condition for the entire experiment. After friction welding we found that different rotation speeds significantly affected mechanical properties of these alloys. At rotation speed 1400 rpm the maximum tensile strength is 122.24 MPa and the maximum hardness in welded zone is 140.5 HV. The microstructure size is 2.250 µm long and 2.144 µm wide. Its size in welded zone is practically small because of friction force. Moreover this friction force causes the mixture of MgZn2 and Mg2Si in welded zone.

This research is to study and develop a DC motor speed control by using Visual Basic.Net 2008 in computer programming to use the computer and the microcontroller is processing from computer via the serial port. So that a signal to the motor driver circuit motor speed work as assigned. By the speed can be entered via the computer screen is measured in rpm. and motor control to control the PWM (Pulse Width Modulation) control circuit and the principles of the hardware by using the digital output signal of the microcontroller control Motor speed can be configured to be from 100 to 3000 rpm. And the motor starts to spin at maximum speed and then gradually reduce the speed down to the specified value. Control both the speed and the average error of 4.6% compared to the speed measurement using infrared light. And found that at speeds below 100 rpm. to a maximum error of 12% and the error decreases when the speed increases. The error value is at least 2000 rpm. and 3000 rpm the speed error is 0.5%