The effects of plant growth regulators alone or in combination on Hexachlorocyclohexane (HCH) phytotoxicity were studied. Waxy corn seeds were immersed in different plant growth regulators that are 1) 2 mg/l Indolebutyric acid (IBA) 2) 2 mg/l Thidiazuron (TDZ) 3) 2 mg/l Gibberellic acid (GA3) 4) 1 mg/l IBA + 1 mg/l TDZ 5) 1 mg/l TDZ + 1 mg/l GA3 and 6) 1 mg/l IBA + 1 mg/l GA3 then sawn in 30 mg/kg HCH-contaminated soil or non-contaminated soil for 10 days. All plant growth regulators could enhance shoot and root dried weight of waxy corn seedlings in non-contaminated soil. Only 2 mg/l GA3 could enhance root length of waxy corn seedlings in non-contaminated soil. In HCH-contaminated soil only 2 mg/l TDZ could increase shoot dried weight of waxy corn seedlings. Also 2 mg/l IBA or 1 mg/l IBA and1 mg/l GA3 could increase root fresh weight of waxy corn seedlings. The exposure with HCH in soil did not affect to shoot and root tissue even though the growth of shoot and root were inhibited. However the exposure with HCH and receive exogenous plant growth regulator induced aerenchyma formation in cortex and pith of waxy corn root.

This research aims to study the effect of drying temperature on the changes in the moisture content of charcoal briquettes undergoing drying of solar energy and far-infrared radiation (Solar+FIR) and far-infrared radiation (FIR). The electricity consumption and the specific energy consumption were also investigated. The coconut shell charcoal briquettes with the initial moisture content of about 41-43% MW were dried at 55 60 and 65oC until the final moisture content of 8% MW was obtained. Based on the experimental results it was found that the drying temperatures and the drying methods had effects on the changes in the moisture content of charcoal briquettes. Drying at high temperature could reduce the moisture content of charcoal briquettes faster than that at low temperature. Drying using FIR could reduce the moisture content of charcoal briquettes faster than that using Solar+FIR. Moreover the electricity consumption and the specific energy consumption decreased with an increase in the drying temperature. Drying using Solar+FIR had lower electricity consumption but had higher specific energy consumption than drying using FIR. In this study the charcoal briquettes had the average heating value of about 6667.05 cal/g.

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 aims to study the using a rubber sheet instead of the sulfur-capping accordance with ASTM C 617 in the compressive strength of concrete testing. The three of the compressive strength of concrete i.e. 180 240 and 320 ksc were the scope of study. The test results showed that the concrete with using a rubber sheet (fc (3)) had higher compressive strength than the standard concrete with sulfur-capping (fc (2)) at 7.7%. Therefore the adjustment factor from using a rubber sheet instead of the sulfur-capping in the compressive strength of concrete testing was 0.923; the compressive strength of concrete is equivalent to the standard testing. The relationship of compressive strength of concrete between fc (2) and fc (3) is fc (2) = 0.88 fc (3) + 12.04 with a correlation coefficient (r) of 0.988.

This research is aimed to developed and evaluate a competency model of production engineer in the automotive industry. The data is collected from Amata City Rayong. The research is performed with two steps: 1) create an engineering competency in the automotive industry using Delphi technique with 17 experts. Then 2) review the engineering competency with the focus group of management staffs from automotive industry in Amata City Rayong. The statistics used in the analysis were percentile median and inter-quartile range. The results show that competency is consist of three parts. Part 1: management competency Part 2: functional competency Part 3: production engineering characteristic and consisted of four parts 1) the management of operational performance 2) production engineering 3) engineering knowledge 4) personal characteristics. Examining results in the competency model of production engineer in the automotive industry: the data is collected from Amata City Rayong created are appropriate and feasible in practice and performance as a performance model is built according to expert opinion.