scholarly journals Non-clairvoyant Scheduling to Minimize Max Flow Time on a Machine with Setup Times

2018 ◽  
pp. 207-222
Author(s):  
Alexander Mäcker ◽  
Manuel Malatyali ◽  
Friedhelm Meyer auf der Heide ◽  
Sören Riechers
Keyword(s):  
Flow Time ◽  
Setup Times

Effect of routing flexibility and sequencing rules on performance of stochastic flexible job shop manufacturing system with setup times: Simulation approach

2016 ◽  
Vol 231 (2) ◽  
pp. 329-345 ◽  
Author(s):  
Pankaj Sharma ◽  
Ajai Jain
Keyword(s):  
Performance Measures ◽  
System Performance ◽  
Manufacturing System ◽  
Job Shop ◽  
Flow Time ◽  
Setup Times ◽  
Flexible Job Shop ◽  
Routing Flexibility ◽  
Due Date ◽  
Sequencing Rule

Routing flexibility is a major contributor towards flexibility of a flexible job shop manufacturing system. This article focuses on a simulation-based experimental study on the effect of routing flexibility and sequencing rules on the performance of a stochastic flexible job shop manufacturing system with sequence-dependent setup times while considering dynamic arrival of job types. Six route flexibility levels and six sequencing rules are considered for detailed study. The performance of manufacturing system is evaluated in terms of flow time related and due date–related measures. Results reveal that routing flexibility and sequencing rules have significant impact on system performance, and the performance of a system can be increased by incorporating routing flexibility. Furthermore, the system performance starts deteriorating as the level of route flexibility is increased beyond a particular limit for a specified sequencing rule. The statistical analysis of the results indicates that when flexibility exists, earliest due date rule emerges as a best sequencing rule for maximum flow time, mean tardiness and maximum tardiness performance measures. Furthermore, smallest setup time rule is better than other sequencing rules for mean flow time and number of tardy jobs performance measures. Route flexibility level two provides best performance for all considered measures.

scholarly journals A branch and bound method in a permutation flow shop with blocking and setup times

2022 ◽  
Vol 13 (2) ◽  
pp. 255-266 ◽  
Author(s):  
Marcelo Seido Nagano ◽  
Mauricio Iwama Takano ◽  
João Vítor Silva Robazzi
Keyword(s):  
Branch And Bound ◽  
Flow Shop ◽  
Flow Time ◽  
Setup Times ◽  
Total Flow ◽  
Permutation Flow Shop ◽  
Flow Shop Problem ◽  
Limited Buffers ◽  
Manufacturing Environments ◽  
New Machine

In this paper it is presented an improvement of the branch and bound algorithm for the permutation flow shop problem with blocking-in-process and setup times with the objective of minimizing the total flow time and tardiness, which is known to be NP-Hard when there are two or more machines involved. With that objective in mind, a new machine-based lower bound that exploits some structural properties of the problem. A database with 27 classes of problems, varying in number of jobs (n) and number of machines (m) was used to perform the computational experiments. Results show that the algorithm can deal with most of the problems with less than 20 jobs in less than one hour. Thus, the method proposed in this work can solve the scheduling of many applications in manufacturing environments with limited buffers and separated setup times.

Etching of Polymers by Oxygen Plasma

1968 ◽  
Vol 26 ◽  
pp. 408-409
Author(s):  
Virgil Peck ◽  
W. L. Carter
Keyword(s):  
Molecular Weight ◽  
Oxygen Plasma ◽  
Flow Time ◽  
Microscopical Study ◽  
Surface Layers ◽  
Organic Vapors ◽  
Sample Position ◽  
Accuracy Of Measurement ◽  
Bulk Polymers ◽  
Electron Microscopical

Any electron microscopical study of the morphology of bulk polymers has throughout the years been hampered by the lack of any real ability to produce meaningful surface variations for replication. True etching of polymers should show crystalline and amorphous regions in some form of relief. The use of solvents, acids, organic vapors, and inert ion bombardment to etch samples has proved to be useful only in limited applications. Certainly many interpretations of these results are subject to question.The recent use of a radiofrequency (R. F.) plasma of oxygen to degrade and remove organic material with only minor heating has opened a new possibility for etching polymers. However, rigid control of oxygen flow, time, current, and sample position are necessary in order to obtain reproducible results. The action is confined to surface layers; the molecular weight of the polymer residue after heavy etching is the same as the molecular weight of the polymer before attack, within the accuracy of measurement.

Sign in / Sign up

Export Citation Format

Share Document