Research Article
Inventory Calculation for an Item Supplied by Three Providers with Stochastic Lead Times
Issue:
Volume 10, Issue 3, June 2025
Pages:
27-37
Received:
16 April 2025
Accepted:
27 April 2025
Published:
29 May 2025
Abstract: This study aims to answer whether the policy of a business that is supplied by 3 different providers and with random patterns of their lead times is optimal or should be modified. The lead times are normal, the first one, uniform the second one and exponential the third. The three lead times have the same average value of eight days, with the objective of making a comparison of them. There is a restriction on the minimum service level, it has to be 95% or greater. The objective is to define the order quantity, the reorder point, and the fraction that should be ordered from each supplier to minimize inventory costs. The item has a normally distributed demand. Results were achieved by simulation that was made in Excel. The current policy of obtaining a third of the complete order from each supplier is satisfactory; however, it doesn´t produce the optimal cost, since lower-cost options were found. A sensitivity analysis was conducted to establish how inventory costs are affected by the variation of some parameters. The third supplier, with exponential pattern of lead time showed the highest variance of delivery time; thus, it has been the least recommended, since it has been the option with the highest cost.
Abstract: This study aims to answer whether the policy of a business that is supplied by 3 different providers and with random patterns of their lead times is optimal or should be modified. The lead times are normal, the first one, uniform the second one and exponential the third. The three lead times have the same average value of eight days, with the objec...
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Research Article
Microabrasive Wear Test Procedure for Characterization of High Hardness Ferrous Materials
Issue:
Volume 10, Issue 3, June 2025
Pages:
38-45
Received:
9 January 2025
Accepted:
30 April 2025
Published:
6 June 2025
DOI:
10.11648/j.eas.20251003.12
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Abstract: The ball cratering microabrasive wear test is a method whose feasibility in wear resistance characterization of metallic materials has been demonstrated in numerous investigations, however, there is still no standard that establishes the procedure for its application and the test requirements. This leads to the need to establish, through prior experimentation, the test procedure suitable for specific applications. In the present work, a microabrasive test procedure was obtained, aimed at the characterization of high alloy and hard ferrous materials, based on the quality of the wear mark, the behavior of the crater diameter with respect to the test time and the results dispersion. It was demonstrated that, by using alumina as the abrasive material, with a concentration of 10 g per 100 ml of water, a dropping frequency of one drop every 5 seconds, a test force of 0.27 N, a shaft rotation speed of 80 rpm and a test time of 10 minutes, reliable measurements are obtained in a permanent wear regime, which shows the importance of adapting this test parameter to the type of under-study material. It was also found that there is a correspondence between the hardness and the microstructure of the material with the average size of the wear crater and the dispersion of results.
Abstract: The ball cratering microabrasive wear test is a method whose feasibility in wear resistance characterization of metallic materials has been demonstrated in numerous investigations, however, there is still no standard that establishes the procedure for its application and the test requirements. This leads to the need to establish, through prior expe...
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Jose Adrian Najera Saldaña
