Buffer allocation in stochastic flow lines via sample-based optimization with initial bounds

This paper studies the problem of allocating buffers in stochastic production flow lines with product travel time. We build a model that decomposes the production line into the S-B-S (Station-Buffer-Station) subsystems, and use queueing theory to aggregate the subsystems. Experiments are designed for both balanced and unbalanced production lines, and with the computational results, some general rules for the buffer allocation problem are proposed.

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Buffer allocation problem in production flow lines: A new Benders-decomposition-based exact solution approach

IISE Transactions ◽

10.1080/24725854.2021.1905195 ◽

2021 ◽

pp. 1-15

Author(s):

Mengyi Zhang ◽

Erica Pastore ◽

Arianna Alfieri ◽

Andrea Matta

Keyword(s):

Exact Solution ◽

Benders Decomposition ◽

Allocation Problem ◽

Buffer Allocation ◽

Production Flow ◽

Flow Lines ◽

Solution Approach

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Thermodynamic Modelling of Gas Hydrate Formation in the Presence of Inhibitors and the Consideration of their Effect

ASEAN Journal of Chemical Engineering ◽

10.22146/ajche.49715 ◽

2014 ◽

Vol 14 (1) ◽

pp. 45

Author(s):

Peyman Sabzi ◽

Saheb Noroozi

Keyword(s):

Gas Hydrates ◽

Gas Hydrate ◽

Low Temperatures ◽

Hydrate Formation ◽

Transportation Systems ◽

Flow Lines ◽

Main Approach ◽

Efficient Inhibitor ◽

System A ◽

Gas Hydrate Formation

Gas hydrates formation is considered as one the greatest obstacles in gas transportation systems. Problems related to gas hydrate formation is more severe when dealing with transportation at low temperatures of deep water. In order to avoid formation of Gas hydrates, different inhibitors are used. Methanol is one of the most common and economically efficient inhibitor. Adding methanol to the flow lines, changes the thermodynamic equilibrium situation of the system. In order to predict these changes in thermodynamic behavior of the system, a series of modelings are performed using Matlab software in this paper. The main approach in this modeling is on the basis of Van der Waals and Plateau's thermodynamic approach. The obtained results of a system containing water, Methane and Methanol showed that hydrate formation pressure increases due to the increase of inhibitor amount in constant temperature and this increase is more in higher temperatures. Furthermore, these results were in harmony with the available empirical data.Keywords: Gas hydrates, thermodynamic inhibitor, modelling, pipeline blockage

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The Effect of Station Breakdowns and Random Processing Times on the Capacity of Flow Lines with In-Process Storage

A I I E Transactions ◽

10.1080/05695557208974867 ◽

1972 ◽

Vol 4 (4) ◽

pp. 308-312 ◽

Cited By ~ 66

Author(s):

John A. Buzacott

Keyword(s):

Flow Lines ◽

Processing Times ◽

Station Breakdowns

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The Effect of Flow Lines on the Mechanical Properties in Hot-Rolled Bearing Steel

Metals ◽

10.3390/met11030456 ◽

2021 ◽

Vol 11 (3) ◽

pp. 456

Author(s):

Dongsheng Qian ◽

Chengfei Ma ◽

Feng Wang

Keyword(s):

Mechanical Characterization ◽

Tensile Deformation ◽

Flow Line ◽

Plastic Property ◽

Bearing Steel ◽

Mechanical Anisotropy ◽

Flow Lines ◽

Significant Difference ◽

Hot Rolled ◽

Bearing Rings

Hot rolling is an essential process for the shape-forming of bearing steel. It plays a significant role in the formation and distribution of flow lines. In this work, the effect of flow lines is investigated by analyzing the microstructure and mechanical anisotropy of hot-rolled bearing steel. It was found that carbides rich with Cr and Mn elements are distributed unevenly along the flow-line direction of the hot-rolled bearing steel. Moreover, the mechanical characterization indicates that ultimate tensile strength and yield strength do not have any significant difference in two directions. Nevertheless, an ultrahigh section shrinkage of 57.51% is obtained in the 0° sample that has parallel flow lines, while 90° sample shows poor section shrinkage. The uneven distributed carbides will affect the direction and speed of crack propagation during tensile deformation. Therefore, the 0° and 90° samples exhibit great difference in plastic property. Meanwhile, after tensile deformation, a delaminated texture is observed in the flow lines, which may be caused by different degrees of deformation of grains due to the uneven distribution of carbides. The results of this work may provide guidance for controlling and optimizing flow lines in the manufacturing of bearing rings.

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