This quantitative research aimed 1) to study operation performance of Thai Gem Businesses. 2) To study factors affecting firm performance of Thai Gem Businesses. The research was collected data by using questionnaire with 452 participants from production group of Thai Gem Businesses. The samples were collected conveniently and analyzed by frequency percentage mean standard deviation Pearson’s correlation coefficient and analysis confirmatory with Structural Equation Modeling: SEM. It was one of all statistic techniques to test for causal relationship of variables. The results found that database information management systems have positively affect strategic management and firm performance of Thai Gem Businesses with significant level 0.05. Database information management systems also have positive affect on strategic management of Thai Gem Businesses with significant level α < 0.05. Besides this research results found that database information management systems has positively direct and indirect affecting firm performance by pass strategic management with direct affect on firm performance equal to 0.346 and indirect affect by pass strategic management equal to 0.575. And total affect was equal to 0.921 with significant level. It showed that overall affect of database information management system on firm performance was more than strategic management affect to Firm Performance (0.603) with significant level 0.05. The analysis of correlation coefficient model showed that measurement between latent variables have positive correlation with significant level α < 0.05. The analysis of Structural Equation Model revealed that it wassuitable harmonize with empirical data ( χ2 / df = 1.489 CFI = 0.997 AGFI = 0.957 RMSEA = 0.08 RMR = 0.004) and consistent with the define hypothesis. The research results described the environmental of firm performance approach to strategic management by TOWS Matrix and recommendation on strategic management to solve problems on firm performance of Thai Gem Businesses in order to develop continuous firm performance for competitive advantage.

This research aimed 1) to study levels of transformational leadership innovative climate knowledge management systems innovative work behaviors and firm performances 2) to investigate causal relationship of transformational leadership innovative climate knowledge management system as well as innovative work behaviors which influenced on performances of the Medical Device Business in Thailand 3) to examine relevance of those variables along with causal relationships of the antecedents affecting performance of the Medical Device Business in Thailand to empirical data. Data were collected from 312 middle level managers in Medical Device Business in Thailand by using questionnaires as a research instrument. All of the data were analyzed using Structural Equation Model. The analysis of correlation coefficient model showed that the latent variables significantly related to one other at statistical level of 0.001. The analysis of structural equation model (SEM) revealed that the model was completely compatible with the empirical data and the hypothesis. (GFI = 0.933 CFI = 0.972 RMSEA = 0.078 RMR = 0.018) The findings also showed that transformational leadership significantly affected innovative work behaviors at statistical level of 0.001. Similarly innovative climate significantly affected innovative work behaviors at statistical level of 0.001. Likewise knowledge management system significantly affected innovative work behaviors at statistical level of 0.001. Finally innovative work behaviors significantly and directly affected the firm performance at statistical level of 0.05.

The research objective is to study the relationship between environmental disclosure levels corporate governance and the performance of companies listed in the Real Estate and Construction group on the Stock Exchange of Thailand. It was conducted by collecting information from the financial statements the annual reports and the information registration forms (Form 56-1) of 91 companies from 2015 to 2019. Descriptive statistics and inferential statistics were used in data analysis including correlation analysis and multiple regression analysis. The study results showed that environmental disclosure levels including environmental policy disclosure and other environmental disclosures positively correlate with the rate of return on equity return on total assets with a statistical significance at 0.01 and 0.05 levels. Corporate governance including the percentage of shareholding by the management and the number of the Board of Directors positively correlates with the return on total assets with a statistical significance at 0.01 and 0.05 levels.

The purpose of this research is to develop a hot air dryer using waste heat from a200 liter kiln for drying bananas and to investigate its drying performance. The main parts of the dryer consist of the drying chamber that has dimensions 0.71x0.83x.091 m3 the air circulation system and a heat exchanger which receives waste heat from the exhaust tube and kiln surface. The dryer was developed by designing a drying chamber on the top of a 200 liter kiln to reduce heat lost in the structure and an exhaust gas heat exchanger was developed using groups of copper tubes for increasing then heat transferred to the air. The drying performances were analyzed by measuring specific drying rates and specific energy consumption. Experiments were performed under different temperatures of 60 70 and 80℃ And at a constant velocity of 1.8 ms-1. Eucalyptus was selected as the heat source. Thirty kg of peeled bananas were prepared at an initial moisture content of 241.19±31.50% dry basis and were dried until to final moisture content of 48.47±10.46% dry basis. All experiments were carried out in duplicate. For temperatures of 60 70 and 80 ℃ the ave age specific drying rates were 0.085±0.0004 0.114±0.0009 and 0.1277±0.010 kg water h-1kesolid-1 and the average specific energy consumptions were 1.42±0.055 1.21±0.355 and 1.04±0.074 MJ/kg water respectively. Some dried bananas had burned at a temperature of 80℃ so at temperature of 70 ℃ was the optimal condition in this experiment. This produced good color a high specific drying rate and low specific energy consumption.

The objective of this work is to investigate the effects of water injection on performance of 5-stroke SI engine converted from the conventional 4-stroke SI engine.The cylinder head of the 2ndand3rd cylinder was modified and connected to each other to be the ultra-expansion stroke or second expansion stroke (5thstroke). The engine was performed on a dynamometer at different engine speeds and loads of 1500 to 3000 rpm and 25% to 75% of full load respectively. The water was injected during the second expansion stroke (5th stroke). Fuel and air consumptions engine torque rotational speed air/fuel ratio and temperatures of intake air engine oil cooling water and exhaust gas were recorded to use for calculating brake specific water and exhaust gas were recorded to use for calculating brake specific fuel consumption (BSFC) and engine efficiency. The results showed that at low engine speed of 1500 rpm for all loads the water injection improves BSFC and the engine efficiency by 26% and 3.3% respectively. However a large amount of injected water shows insignificant improvement on BSFC and the engine efficiency due to short residence time especially at high engine speed. The deterioration of engine oil can be observed after test. These findings are relevant to engine design or modification especially at low engine speed.