In this paper the effects of carbonation on pore structure of blended pozzolan cement pastes were investigated. Ordinary Portland cement _OPC_ was partially replaced with ground palm oil fuel ash _POA_ ground rice husk ash _RHA_ and classified fine fly ash _FA_. The strength total porosity specific surface area and pore size distribution were tested. In general incorporation of pozzolans increased the total porosity of blended cement pastes in comparison to that of OPC paste. Carbonation of pastes under 5% CO2 and 50% relative humidity _RH_ for 28 days resulted in filling of the pore voids and possible attack on calcium silicate hydrate _CSH_ depending on the type of pozzolan used. After carbonation total porosity decreased and specific surface areas of the blended pozzolan cement pastes reduced indicating the infilling of voids. Pore size distributions of POA and RHA pastes were different to those of FA pastes. Large pores of the POA and RHA pastes were increased indicating coarsening of pores owing to possible attack on CSH. It is possible that POA and RHA were highly reactive and hence their uses resulting in severe carbonation compared to use of FA.

This paper presents a study of the strength porosity and corrosion resistance of mortars made with ternary blends of ordinary Portland cement (OPC) ground rice husk ash (RHA) and classified fly ash (fine fly ash FA). Compressive strength porosity and accelerated corrosion with impressed voltage (ACTIV) were tested. The results show that the use of ternary blend of OPC RHA and FA produces mortars with improved strengths at the low replacement level with RHA and FA and at the later age in comparison to that of OPC mortar. The porosity of mortar containing pozzolan reduces with the low replacement level of up to 20% of pozzolan but increases with the 40% replacement level. The chloride induced corrosion resistance of mortar as measured by ACTIV is however significantly improved with the use of both single pozzolan and the ternary blend OPC RHA and FA. The corrosion resistance of ternary blend mortar is higher than that of mortar containing single pozzolan. The use of ternary blend OPC RHA and FA is very effective in enhancing chloride induced corrosion of mortar.

This research aims to investigate the efficiency and quality of young rice planting machine which is suitable for the North Eastern part of Thailand. The investigation applies the notions of planting young rice manually by farmers into the design of a battery-driven young rice planting machine. The researcher started with the study of transplanting methods of agriculturists in the North Eastern part and the design principles of young rice planting machine. Next the components were calculated and engineering design was drawn. Then the machine was tested in terms of its efficiency and quality. The data were analyzed in terms of means. The results show that the efficiency of the machine regarding planting performance is 90 % the appearance of the machine functions applications engineering and safety achieve the average point of 3.70 which is considered satisfactory.

The objectives of this research were the determination of sorption isotherms and the comparison of mathematical models to determine a suitable model in different temperature ranges for Khao Dawk Mali 105. This experiment was made by placing samples in containers which were contained saturated salt solutions to control the humidity in the ranges of 5.32 – 84.34 %RH and the hot air oven was used to provide temperature conditions at 25 and 70 oC. The samples were in containers until the mass of samples was constant so the equilibrium between the samples and the surrounding was reached and then the equilibrium moisture content was determined. The experiment found that for the same relative humidity in the air when the temperature increased the equilibrium moisture content would decrease and for the same temperature in the air when the relative humidity increased the equilibrium moisture content would increase. Furthermore the comparison of models by analysis from R-Squared (R2) and Chi-Square (χ2) in each temperature found that Henderson model was a suitable model at 25 oC and Chung & Pfost was a suitable model at 70 oC.

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.