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The selection of the welding process is a matter of decision-making involving a variety of information according to the type of product.Accordingly, the vast information will significantly enhance the decision-making process. A combined p-robust technique, fuzzy credibility constrained programming and data envelopment analysis (DEA) are proposed to select the welding process for repairing the shredder hammer. The p-robust technique has regret value to control relative regret of data, and fuzzy credibility constraint programming has confidence level to satisfy chance constraints. In addition, the proposed approach is able to handle fuzzy input data and fuzzy output data to uncertainty data. The proposed method is used to investigate which welding process is best based on two cases. Three welding processes are analyzed for the first case that focuses on manual welding process, and four welding processes are investigated for the second case that focuses on automatic welding process. According to the results, increasing the credibility level would also increase the discrimination power of the proposed approach, so the ranking of DMUs could be seen easily. [ABSTRACT FROM AUTHOR]

A small, novel wheat drying oven was designed, and tested in order to validate the possibility of recovering diesel engine waste heat as thermal energy. Prior to experiments, the theoretical probability was conducted, and it was confirmed that the thermal energy required for drying wheat could be satisfied by reusing the diesel engine waste heat. Three different experiment parameters, including air temperature, baffle angle, and drying time, were controlled to optimize the results. Based on the experiment data, the optimum temperature for drying wheat was 55°C, and the optimum baffle angle was 23.25°. The drying efficiency decreased as the drying temperature and drying time increased. The moisture content of wheat decreased from 26.0% to 20.0% with 55°C hot air when the proposed wheat drying oven was used. The test results demonstrated that the proposed oven could be made to work. [ABSTRACT FROM AUTHOR]

The multivariate control charts are not only used to monitor the mean vector but also can be used to monitor the covariance matrix. The multivariate variability charts are used to guarantee the consistency of products in the subgroup. Many researchers have been studied the multivariate control chart for variability. Nevertheless, those conventional methods have several drawbacks because it is developed based on the determinant of the covariance matrix and not free of the measurement unit. To overcome such issues, this paper proposes the multivariate control chart for variability based on trace of the squared correlation matrix. Kernel Density Estimation is used to improve estimated control limit. The kernel density estimation method is used to calculate the control limit. Through simulation studies, the performance of the proposed chart is evaluated using the average run length (ARL). The control limits of the proposed chart are produced in control ARL at about 370 for α = 0.00273. Meanwhile, the proposed chart demonstrated better performance to detect the shift for the large value of quality characteristics and sample size. The proposed chart also produces a better performance than the conventional generalized variance chart when used to monitor the real case data. [ABSTRACT FROM AUTHOR]

This work mainly focus on finding the optimal conditions for improving the efficiency of the dissimilar welded joints that were prepared using the friction stir welding (FSW) process. To carry out further research on the FSW process, it is very important to know the significant process parameters. As per the literature, rotational speed, welding speed, and tilt angle are the most significant parameters and hence have been considered in the current investigation on output responses are tensile strength, impact strength, and elongation are the multi-responses identified; they were also investigated with the help of two-dimensional (2D) plots. The experimental design is planned as per the Taguchi L9 orthogonal array. The straight cylindrical threaded tool is used in this work. AL6082-T651 and AL7075-T651 alloys are taken as the workpiece material based on its applications. The workpieces are cut as per the American Society for Testing and Materials standards. After performing the experiments, each output response is measured at all the welding conditions and is tabulated. This experimental data is used for optimizing the multi-responses using the Taguchi Grey relational analysis (GRA) method. This GRA method helps optimize the multi-responses in an FSW process. In the process of optimization using the GRA method, the signal-to-noise ratios, the Grey relational coefficients, and the Grey relational grades are calculated, and ranking will be given based on the Grey relational grade values. Overall, this method proves suitable for optimizing the multi-responses in the FSW process. [ABSTRACT FROM AUTHOR]

The design of facility layout is an influential factor in a company's performance to support the streamlined process of production. PT. PMJ is one of the garment industries that produce women's underwear. The total processing time in the sewing department often exceeds the standard time set by the company. The composition of the machine and facilities at the sewing department is considered to be not optimal. The order of machines in the production line has not been arranged appropriately which causes the excessive distance in the material transfer. In addition, the uses of straight material flow cause the workers to rotate their posture of the body when taking the materials. Based on the results of the assessment of the condition of workers in the initial facility layout using the Quick Exposure Check (QEC) method, the highest total exposure score is on the back. This study aims to redesign the facility layout of PT. PMJ using Systematic Layout Planning (SLP) and ergonomics approach to minimize total material handling cost. Two design alternatives are proposed and the performance of each design is evaluated using ARENA simulation software. Based on the calculation of total material handling cost and simulation, the second proposed facility layout was chosen since it was able to reduce the total material handling cost by 22.92% and material transfer time by 34.01%. [ABSTRACT FROM AUTHOR]