Influence of Shielding Gas on Aluminum Alloy 5083 in Gas Tungsten Arc Welding

AbstractThe influence of shielding gas parameter was affect to mechanical properties and microstructures of heat-affected zone and fusion zone on gas tungsten arc welding (GTAW) in aluminium alloy AA 5083. The factorial experiment was designed for this research. The factors of AA 5083 weld used in the study types of shielding gas in argon and helium, gas flow rate at 6, 10 and 14 litres per minute. Then the results were using microstructure and vickers hardness test. The result showed that types of shielding gas and gas flow rate interaction hardness at heat-affected zone and fusion zone with a P–value < .05. The factor which was the most effective to the hardness at heat-affected zone and fusion zone was argon with a flow rate of 14 litres per minute at heat-affected zone with 74.27 HV and fusion zone with 68.97 HV. The helium was high thermal conductivity, resulting in a large amount of heat. The grain size was grain growth in larger grain size. This can result in decreased of hardness. Experimental results showed that the argon condition provided smaller grain size, suitable size resulting in higher hardness both in weld metal and HAZ. This research can be used for data on considering on gas tungsten arc welding of aluminium alloy 5083

Activity-Based Costing Analysis for Train Station's Service

Laem Chabang train station is subsidiary to container transportation office of The State Railway of Thailand. Its main objective is to provide services to container and oil trains of&nbsp;about 900 - 1000 container trains and 120 oil trains (inbound-outbound) each month. Its operation is divided into two main part: Laem Chabang station and Laem Chabang Port station operates 24 hours a day. This report does research on services of both stations. The services can be categorized into two types: container train service and oil train services which are different in their processes. This report analyze activity-based costing especially in the Laem Chabang train station's direct expense which is not include other organizations' expenses such as mechanical department, civil department or signaling department. Formerly, The State Railway of Thailand had not been calculating this kind of cost, the workgroup thus attempts to make activity-based costing of Laem Chabang train station to improve its service procedure and reduce its future cost. From calculation cost of service of Laem Chabang train station by applying activity-based costing, the cost of activity for each type of train is revealed. The cost of service for oil train is 1,575.85 baht per train, for container train entering zone B port is 809.61 bath per train and for container train entering zone C port is 811.76 bath per train. It is found that cost of service for oil train is the highest due to its lower client which is about one-eighth of container train; that is conforms to the law of demand and supply. In order to reduce cost, it can be considered to operate more oil trains or to decrease the number of labour related to oil train because most of the cost comes from labour salary (about 83%). Thus, optimization of labour can clearly lower overall cost

The Strategy of Visual Inspection for Non-Geometric Parts by using Screen Display Techniques

The objective of this research is to determine the effectiveness of visual inspection strategies with different screen display techniques for non-geometric parts in terms of inspector performance measures to identify an effective strategy for inspecting non-geometric parts. The study is divided into three experimental phases. Phase I and Phase II compare the effectiveness of defect search patterns and training patterns respectively, to determine the best effective patterns. The results of both studies were integrated into screen display techniques to determine the most effective visual inspection strategy by using a visual inspection program in the final phase. Phase III compares the effectiveness of visual inspection with the strategy of screen display technique application. The evaluation of the effectiveness of all phases in regard to the performance of participants was indicated by speed and accuracy of the visual inspection. The results of the studies found that the visual inspection strategy with a hybrid screen display technique was the best strategy for visual inspection. This strategy will make visual inspection performance 13.40 sec faster per piece and increase accuracy by 50.83%. The application of the visual inspection strategy can be a strategy for practice before performing actual inspections and can have applications for other inspection work, especially for defect inspection of non-geometric shapes and complex shapes

Two-Dimensional Mathematical Modeling of the Oxidative Coupling of Methane in a Membrane Reactor

The oxidative coupling of methane (OCM) in a dense BSCFO membrane reactor (MR) was theoretically studied using a two-dimensional reactor model. The simulation results indicated that increasing the operating temperature results in increased CH4 conversion and decreased C2 selectivity. An increase in the methane feed flow rate lowers the CH4 conversion but increases the C2 selectivity; however, the effect of the air flow rate on the OCM membrane reactor exhibits an opposite trend. The optimum configuration of the dense BSCFO-MR to provide the best performance was 0.018 m in diameter and 0.2 m in length at a GHSV of 38904.54 h-1 and temperature of 1073 K. Under these optimal conditions, the CH4 conversion is 43.713%, the C2 selectivity is 61.352% and the C2 yield is 26.82%