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    Evaluation of hardness values in machine part surface hardening process by fuzzy quality control and process capability analysis
    (Pamukkale Univ, 2023) Sengul, Ahmet Bilal; Sengul, Umran
    In the manufacture of machine parts, quenching is a method used in all areas of the industry in different environments and conditions. The obtained hardness values must be in the appropriate value range according to the requirements of the function of the relevant machine part. It is common to measure hardness values according to ASTM E10-01 (Standard Test Method for Brinell Hardness of Metallic Materials), which is one of the hardness measurement methods. In the study, Shewart Average (X) and Range (R) quality control charts and process capability analysis were used to test the compliance of the hardness values obtained as a result of the quenching-tempering process according to the technical drawing of the relevant part in a company manufacturing machine parts. In addition, due to the approximate value of the observation values, the observation values were converted into fuzzy numbers and fuzzy quality control analyzes were performed with the Fuzzy rules method for TFN case method, and process adequacy was measured. According to both methods, as a result of the study, it was determined that the process variability was high and therefore the process was not sufficient.
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    Öğe
    Fuzzy TOPSIS method for ranking renewable energy supply systems in Turkey
    (Pergamon-Elsevier Science Ltd, 2015) Sengul, Umran; Eren, Mirac; Shiraz, Seyedhadi Eslamian; Gezder, Volkan; Sengul, Ahmet Bilal
    Multi-Criteria Decision Making (MCDM) techniques are gaining popularity in energy supply systems. The aim of this paper is to develop the multi-criteria decision support framework for ranking renewable energy supply systems in Turkey. Given the selection of renewable energy supply systems involves many conflicting criteria, multi criteria decision methods (Fuzzy TOPSIS) were employed for the analysis. The Interval Shannon's Entropy methodology was used to determine weight values of the criteria. In this study, alpha = 0.1, 0.5 and 0.9 values based sensitivity analysis were performed. Three alpha-cutting levels were identical to the sequence of alternatives. According to result, the first criterion in preference ranking of renewable energy sources in Turkey is the Amount of Energy Produced, followed by the ranking systems Land use, Operation and maintenance cost, Installed capacity, Efficiency, Payback period, Investment cost, Job creation, and Value of CO2 emission. Thus the multi-criteria analysis showed that the Hydro Power Station is determined to be the most renewable energy supply system in Turkey. Additionally, the Geothermal Power Station, Regulator and Wind Power Station are determined to be the second, third and fourth, respectively. The government of Turkey should invest, in order of priority, in these systems. The government should also evaluate the projects, which are related to these renewable energy resources. (C) 2014 Elsevier Ltd. All rights reserved.