The ORC power plant is a promising technology to generate electricity from low-temperature heat sources. However implementation of the ORC for low capacity electricity generation is unattractive at the commercial level. Scroll compressors are massively produced to be used in refrigeration and air-conditioning applications. Using a scroll compressor in reverse as an expander can reduce the investment cost of low-capacity ORC power plants. In this study 2 scroll compressors that are available in the automotive air-conditioning market of Thailand were modified and used as the expander of a 1 kW ORC power plant. The performances of these 2 scrolls were compared and the plant performance was investigated. A heat source temperature from 100°C to 150°C was supplied to the plant. It was found that the gross power is higher by 18-35% for the larger expander (110 cc/rev) than for the smaller expander (85.7 cc/rev). The larger one provides the isentropic efficiency of 37-76% and the gross power of 806-1926 W. In addition the effects of check valve installation were examined and compared with those of the tests without check valve installation. It was revealed that the isentropic efficiency increases by 18% while the gross power decreases by 4-22% when the check valve was installed.

Non-destructive test with Acoustic Emission technique was used for monitoring of the corrosion in the above ground oil storage tank. In the analytical characteristics of acoustic emission wave however Acoustic Emission test has to be prior used for the location detection of corrosion especially indication of the severity of corrosion. In this research the relationship between the corrosion rate and the sound wave energy was studied. The corrosion and damage detected on the surface of the aboveground storage tank was determined by the Acoustic Emission Test. Nine pieces of low carbon steel grade SS400 was soaked in sodium chloride solution in simulated tanks at concentrations of 1.5 3.5 and 5.5 wt%. Next the corrosion activity was checked by performing with the Acoustic Emission Testing for 1 hour and thus calculating the corrosion rate of the test specimens. From the experiment it was found that the rate of corrosion affects the Acoustic Emission Energy. The corrosion rate was increased with the concentrations of the solution increasing from the corrosion process. The corrosion rate was also increased with the sound wave power increases. Therefore in order to achieve the corrosion rate and the position of the defects on the inner surface of the tank non-destructive testing with acoustic emission technique can be factually chosen for this specific application.

The aim of this research is to create the center of mass testing machine for vehicles with maximum mass 3000 kilograms. By the performance of this machine is able to determine the center of mass 3 axis by horizontal longitudinal and vertical. On the other hand the verities of mass from 50 to 100 kilograms and the several of weight distribution at horizontal and longitudinal are applied to the condition of testing for reasonable to the position of the center of mass. The result of research discovered to the performance of center of mass tester was activated following to test conditions. Furthermore the weight distribution at longitudinal was the highest effect to the horizontal center of mass. By the way the value of weight distribution at horizontal is more effects to the longitudinal center of mass. Moreover increasing of mass was impact to the vertical center of mass and it’s independent to the position of weight distribution.

The objectives of this study were to calculate the probability of type I error power of a test and to compare the performance of three test statistics: Z Student’s t and Welch’s t. Including the recommending the appropriate test statistic. Classification of the population according to five distribution. The ratios of mean group 1 per group 2 were three levels. The ratios of variance group 1 per group 2 were three levels. The sample sizes of two populations were nine sizes. The significance levels that to study were 0.01 and 0.05. The data were simulated by using SAS programming with 1000 replicates. Results of the research were Z test statistic could control the probability of type I error and had higher power of a test than other test statistics but this test is necessary to know the variances of the two groups. Therefore it was appropriate to apply the other test statistics i.e. Student’s t or Welch’s t. If the variances of the two groups were equal Student’s t was a more appropriate test statistic than Welch’s t. But if the variances of the two groups were not equal Welch’s t was a more appropriate. When both sample sizes were large and the population variances were equal we could use any tests since there is no difference in the performance.

Nowadays the automotive industry in Thailand has been widely growing. Brake pad is one of the automotive products that play a vital role in automotive industry because it is the most critical seeurity part. Consequently testing products for quality are extremely requested. However the precise equipment and function tests which show the real effects are not available enough and cost a lot. Therefore they cannot response to the deman in the automotive industry development. In this study the frictional test jigs for friction measurement JIS K7125 [5] and the clutch facings for automobiles JIS D4311 [6]. A study of the frictional test emphasizes on the static friction (μs) and kinetic friction (μk) in different condition. There are 3 specimens of brake pad supposted by the industry company. These specimens were tested and the results from the pin-ondisk and those from the friction testing were compared. The results revealed the correspondence of the two-sided results but the pin-on-disk’s friction coefficient is more than the friction testing’s friction coefficient by 19.56%. Moreover the coefficient of friction varies according to the temperature Besides the static friction (μs) is likely more than kinetic friction (μk) and tends to differ considerably under high pressure condition.