A case study was conducted to design construct and test a thermosiphon economizer for increasing the temperature of feed water by using waste hot water. The simulation of the thermosiphon economizer (heat exchanger) for the establishment of the optimum size was performed using the thermos-economical method. The thermosyphon was made of a total of 80 copper tubes (outside diam.19.05 mm) with evaporative adiabatic and condensation lengths of 300 10 and 300 mm respectively. The working fluid was R-134a filling ratio was 50% by evaporative volume and the thermosiphon was arranged in a staggered form. In testing performance flow rate of the inlet hot water was set at 10 L/min and the controlled inlet temperature of cold water at 25oC. The average flow rate of the cold water was set at 5 7 and 10 L/min respectively. Results showed that the maximum of rate of heat transfer from the condenser section occurred at the flow rate of the cold water of 10 L/min. When test the inlet temperature of hot water of 4555 and 65 o C were used at the inlet volume flow rate of cold water of 10 L/min maximum heat transfer rates from the condenser 4626 8260 and 8790 W were achieved. Moreover the outlet temperature of the cold water which was initially 25o C changed to 311 34 and 37o C respectively. Therefore increasing the outlet feed water temperature reduced energy consumption. The effectiveness of the thermosiphon economizer with the inlet temperatures of hot water of 45 55 and 65o C was 0.47 0.48 and 0.49 respectively.

This paper presents an analysis of transformer faults to determine the damage occurring within the transformer by the frequency response analysis (FRA) method. Enter the frequency from 10 Hz to 3 MHz and then the measured value is compared to the standard reference value. Consider the different graphs of frequency response in various frequency ranges to analyze the deformation of the iron cores and transformer coils to know the internal condition of the transformer. The tests show that the 50 MVA 115 kV/22 kV transformer has severe damage to the high voltage side and low voltage side of phase-A coil. As a result the transformer can not be used in the power system and make a reminder to repair the transformer.

This thesis proposes a method for detecting harmonics current in the adaptive active harmonic filter with Recursive Least Square (RLS) algorithm. The proposed method is based on the theory of noise cancellation adaptive filter. Originally the theory was used for audio signal processing but this thesis is applied to the harmonic current detector of an active harmonic filter. The principle and construction of the harmonic current detector in the adaptive active harmonic current filter with Least Mean Square (LMS) algorithm and Recursive Least Square (RLS) algorithm are presented to compare the efficiency of both algorithms. Then simulate these two algorithms with Matlab-Simulink program to simulate the three case studies. All three case studies that simulate are generally available in industrial plants. The simulation results show that the harmonic current detector in the adaptive active harmonic current filter with the LMS algorithm and the RLS algorithm can detect the harmonic currents in the power systems. However the RLS algorithm is more efficient and has less error value than the LMS algorithm. Therefore it is confirmed that the RLS algorithm proposed in this thesis is appropriate to use with the adaptive active harmonic current filter to really work in the industry.

This paper presents the method to reduced electromagnetic interference from electronic drive for LED lamp to achieve the TIS standard No.1955-2551. According to standard it must have been tested for magnetic field compatibility that are included Magnetic Field Emission: ME Conducted Emission: CE and Coupling Decoupling Network: CDN. The 3 LED lamp which defined as Type A B and C were tested. Each lamps has 16 watt electric power and was different electromagnetic interference of electronic drive. After that the reduce electromagnetic interference circuit has been designed for low frequency. This circuit test was based on Conducted Emission test only. The integrated design was preferable to reduces electromagnetic interference for LED lamp drive device type A to the TIS. standard No. 1955-2551. That design circuit was been trialled in LED lamp drive device type B and C in order monitor efficiency of reduce electromagnetic Interference. The results showed that design circuit can reduce electromagnetic interference from LED lamp drive device type A and B to the standard. For LED lamp drive device types C the design circuit can reduce electromagnetic interference but it still has not achieve the standard.

This study was aimed to study the demographic characteristics of who decided to shop online to explore working-age people’s internet behavior and to investigate the demographic factors influencing internet shopping decisions. The population and sample used in this study were working-age people drawn from Snowball Sampling method. The questionnaire used was distributed through the internet to 400 respondents. The data were collected and analyzed by the computer program through the statistical analysis including frequency percentage mean () standard deviation (S.D.) and two-way analysis (ANOVA). The research results revealed that Marketing mix factors affected the internet shopping decisions of the working-age people in general at high level (= 4.13 S. D. = 0.430) . When looking into each aspect it was found that the price factor highly influenced the online purchasing decisions (= 4.16 S. D. = 0.463) . followed by the product factor (= 4.13 S. D. = 0.452) which was also considered at high level. The promotion factor had high impact on online shopping decision (= 4.13 S. D. = 0.422) as well as the distribution channel (= 4.13 S. D. = 0.386). The result regarding the relationship revealing gender and age (F = gender *age (1357) = 7.128 p < .05 ) had a significant effect on online shopping at the .05 level. Gender * and occupation (4357 ) = 1.503 p < .05 ) had influence on decisions to online shopping with statistical significance at .05. Occupations and income (F * occupation * income (1357) = 11.487 p < 0.5 ) could influence decision making on the internet shopping with statistical significance at .05. Also the relationship between gender and occupation (F * gender occupation ( 4357 ) = 5.237 p < .05 ) had an influence on the choice of the internet shopping decision on price at the .05 level; the relationship of gender and occupation (F * sex occupation ( 1357 ) =8.000 p < .05 ) influenced the decision to shop on the internet in terms of marketing promotion at the .05 level of significance.