• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.10a
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• pp.106-109
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• 2001

Process parameters of roller levelling process are intermesh of each roller, roller angle, roller arrangement and shape of rollers. Experimental optimization of these process parameters is very troublesome because of difficulties in evaluating the straightness of pipes to be levelled quantitatively. Finite element method can be a very efficient way to evaluate the straightness of the pipes and therefore to optimize the process. This paper is concerned with simulation and optimization of a roller levelling process. Process parameters of a 14-roller levller for aluminum T9 pipes are optimized with finite element method and Taguchi method. Parameters of significance in roller levelling process and their optimum are obtained.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.05a
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• pp.201-204
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• 2001

The tension levelling process is performed to elongate the strip plastically in combination of tensile and bending strain so that all longitudinal fibers in the strip have an approximately equal amount of length and undesirable strip shapes are corrected to the flat shape. This paper is concerned with a simulation of the tension levelling process based on the analysis of the unit model for the tension leveller. Analysis technique such as the sequential analysis of the nit model is suggested and verified with the assembly analysis of the unit model for the effective and economic analysis of the full set of the tension leveller. Analysis of the full tension levelling process using sequential unit models is carried out and provides the effect of the intermesh and optimum amount of the intermesh in tension levelling process.

• Transactions of Materials Processing
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• v.11 no.2
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• pp.147-154
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• 2002

The tension levelling Process is Performed to elongate the strip plastically In combination of tensile and bending strain so that all longitudinal fibers In the strip have an approximately equal amount ofn length and undesirable strip shapes are corrected to the flat shape. Thus paper is concerned with a simulation of the tension levelling process based on the analysis of tile unit model for the tension leveller. Analysis technique such as the sequential analysis of the unit model is suggested and verified with the assembly analysis of the unit model for the effective arts economic analysis of the full set of the tension leveller. Analysis of the full tension levelling Process using sequential unit models Is carried out for steel strips with the shape defect and provides the effect of the intermesh and optimum amount of the intermesh in tension levelling process.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2002.05a
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• pp.25-28
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• 2002

This paper is concerned with the design of roller profiles in tube/pipe straightener with both methods of Computer Aided Design and Computer Aided Engineering. Design analysis is carried out from two point of view. The one is the research in the minimization of tube pitch which was very important factor in levelling process. In order to minimize tube pitch, profiles of the roller were calculated so that the contact region between roller and tube was maximized. The other is determination of an optimum amount of intermesh for the proper progress without a jam in levelling process. Generally the jamming trouble was casued by excessive amount of intermesh in levelling process. The optimum amount of intermesh was determined through the finite element analysis.

• Transactions of Materials Processing
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• v.11 no.2
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• pp.138-146
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• 2002

This paper is concerned with the simulation-based process design method involved non-steady state problem of tension levelling considering the elasto-plastic hardening behavior of a metallic strip by a commercial code ABAQUS/Standard. The tension levelling process is peformed to elongate the strip plastically in combination of tensile and bending strain by a controlled manner so that all longitudinal fibers in the strip have an approximately equal amount of length and undesirable strip shapes are corrected to the flat share. Objectives of this paper are the development of a general method for the design of a tension leveller by a finite element method and parameter studies for the deisgn variables such as the applied tension, the roll intermash includes the determination of the steady state using the simple unit of the tension levelling line and the effect of the finite element mesh size on the amount and distribution of the strain calculated. The analysis provides the information about the intermesh effect on the amount and final shapes of the strip and distribution of the strain in order to determine the amount elongation for correction of the irregular share.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2000.10a
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• pp.42-48
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• 2000

This paper is concerned with a simulation-based process design for the tension levelling of metallic strips based on the elasto-plastic finite element analysis with reduced integration and hourglass control. The tension levelling process is performed to elongate the strip plastically in combination of tensile and bending strain by a controlled manner so that all longitudinal fibers in the strip have an approximately equal amount of length and undesirable strip shapes are corrected to the flat shape. The analysis deals with a method for calculating the quantitative level of the curl to investigate the roll arrangements and intermesh suitable to elimination of the curl. The analysis provides the information about the intermesh effect on the amount, the tension effect and distribution of the strain as well as the stress in order to determine the amount of elongation for correction of the irregular shape. The desired elongation is referred to determine the number of work rolls and the value of tension. Especially, the analysis investigates tile effect of the mesh size in the non-steady state finite element analysis on the amount and distribution of the strain.

• Journal of Sericultural and Entomological Science
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• v.33 no.1
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• pp.9-12
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• 1991

A study on dyeing-rate for single and mixture dyeing of silk with acid dyes was carried out. Single and mixture dyeings were performed with levelling and milling dyes at 7$0^{\circ}C$ and at pH 3, pH 4 and pH 5, respectively. The results of this study were summerized as follows : 1. C. I. Acid Orange 7. A) At pH 3, dyeing-rate was more fast in the single dyeing than in mixture dyeing at the beginning of dyeing process. B) At pH 4 and 5, dyeing-rates tend to get very similar in single and mixture dyeing. 2. C. I. Acid Blue 138 A) At all pH value, dyeing-rates were more fast in the mixture dyeing than single dyeing at the beginning of dyeing. B) As the time increased, the difference of dyeing-rate and adsorption amounts between single and mixture dyeing was not shown.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.905-908
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• 2008

The BTL project, 4 years since its operation, has benchmarked the PFI Project in Japan and has been introduced. Given the evaluation step to select a preferred bidder, in a technological factor, the basic plans are corrected and complemented, whereas in a price factor, the low price bidding system is being enforced. There is concern that how to select preferred bidders and how to operate project costs during operation and management period may be problematic. Thus, in this study, using the Analytic Hierarchy Process, the method of deciding the pribrity to select preferred bidders in an early stage of the project and the evaluation model to evaluate the validity of BTL project expenses in process of project enforcement are established. Targeting the group. composed of experts who have experiences in the BTL project. Then, the levelling of evaluation factors and grouping have been carried out as following: LCC analysis and disbursement for government including two more detailed factors.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2008.10a
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• pp.81-82
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• 2008

In order to design the dyeing process of polyester fibers at low liquor ratio the reproducbility and levelness of dyeings were investigated at various dyeing scale. The levelness was evaluated statistically from color strength obtained at different sections of each piece of dyed fabrics. As the dyeing scale increased, levelling properties was improved.

• Journal of the Korea Institute of Building Construction
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• v.8 no.6
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• pp.155-160
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• 2008

The BTL project, 4 years since its operation. has benchmarked the PFI Project in Japan and has been introduced. Given the evaluation step to select a preferred bidder, in a technological factor, the basic plans are corrected and complemented, whereas in a price factor, the low price bidding system is being enforced. There is concern that how to select preferred bidders and how to operate project costs during operation and management period may be problematic. Thus, in this study, using the Analytic Hierarchy Process, the method of deciding the priority to select preferred bidders in an early stage of the project and the evaluation model to evaluate the validity of BTL project expenses in process of project enforcement are established. Targeting the group composed of experts who have experiences in the BTL project. Then, the levelling of evaluation factors and grouping have been carried out as following : LCC analysis and disbursement for government including two more detailed factors.