• 한국염색가공학회:학술대회논문집
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• 한국염색가공학회 2009년도 학술발표대회
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• pp.175-176
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• 2009

Energy saving and environment-friendly dyeing method of cotton with reactive dyes is the ultra low liquor ratio dyeing because it reduces the total quantity of water, dye, salt and alkali during the dyeing process in the effluent as well as the energy consumption. However, this method may not guarantee the quality of the dyeing results due to the specs or unlevel dyeing depending upon the dyes used. The study has focused on the effect of leveling agents in the dyeing of cotton with reactive dyes under the ultra low liquor ratio (1:5). Especially Sunfix N/B MF-D which was selected for ULLR showed low-leveled dyeing comparing with the other MF-D series. A leveling agent having polycarbonate structure increased LDF values of Sunfix N/B MF-D without changing of dyeing fastness. We recommend some leveling agents to improve the leveling behavior for ULLR dyeing.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 춘계학술대회 논문집
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• pp.326-329
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• 2009

In order to analyze the effect of leveling conditions on residual stress evolution of hot rolled high strength steels, a numerical algorithm was developed. It was able to implement the effect of plastic fraction (intermesh) in leveling, line tension, work roll bending, and initial residual stress and curl distribution. The effect of work roll bending on residual stress and curl were studied by using the developed program. The validity of simulated results was verified from comparison with the experimentally measured residual stress and curl in a sheet.

• 한국산학기술학회논문지
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• 제17권5호
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• pp.372-378
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• 2016

항만 구조물인 케이슨 및 블록 등을 수중에 거치하기 위해서는 기초사석을 투하하고 이 위에 구조물을 설치한다. 이때 기초 사석은 상구구조물을 지지하기 위한 기초 토대로서 사석의 규격, 비중, 중량 모양 및 치수 등이 균일하고 치밀하여야 하며 선정시험을 통과한 사석만을 사용하여 시공하야 한다. 또한 이러한 기초 사석을 고르게 만들어 주는 작업 구조물의 거치 이전에 반드시 이루어 져야 한다. 본 연구에서는 수중 고르기 작업 공정의 무인화를 위하여 수중 고르기 및 굴삭용 무인기계 뿐만 아니라 무인기계화 시공을 위한 원격제어용 운영시스템, 수중 물체 인식 및 수중위치 분석을 위한 수중 환경 모니터링 시스템이 개발되었다. 본 장비는 육상 및 수중 테스트를 통하여 검증을 완료 하여 우수한 성능을 확인하였다. 그러나 현장에 본 장비를 투입하기 위해서는 성능뿐만 아니라 건설 공정의 제안 및 분석 그리고 효율(경제성)이 분석되어야 한다. 본 연구에서는 수중고르기장비의 성능 및 기능, 건설공정절차, 기존의 공법과의 비교 분석하였다. 분석결과 기존의 잠수부를 투입하는 건설공법에 비하여 경제성, 효율성, 안전성이 향상되는 것으로 확인되었다.

• International Journal of Precision Engineering and Manufacturing
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• 제2권1호
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• pp.18-25
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• 2001

Electrolytic polishing is the anodic dissolution process in the transpassive state. It removes non-metallic inclusion and improves mechanical and corrosion resistance of stainless steel. If there is a Bailby layer, it will be removed and the true structure of the surface will be restored. Electrolytic polishing is normally used to remove a very thin layer of material from the surface of metal object. A new electrolyte composed of phosphoric, sulfuric and distilled water has been developed in this study. Two current density, high & low current density regions, have been applied in this study. In this study, In the region of high current density, there is no plateau region but excellent electrolytic polishing effect can be accomplished in short machining time because material removel process and leveling process occur simultaneously. In the low current density region, there can be found plateau region. The material removal process and leveling process occur successively. The aim of this work is to determine electrolytic polishing for stainless steel in terms of high & low current density and workpiece surface roughness.

• 소성∙가공
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• 제31권5호
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• pp.296-301
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• 2022

In this study, influence of the process parameters of the roller leveling process on the straightness of the steel wire was analyzed using numerical analysis. To construct the numerical analysis model, cross-sectional and longitudinal element sizes, which affect the prediction accuracy of longitudinal stress caused by bending deformation of the steel wire, were optimized, and mass scaling that satisfies prediction accuracy while reducing computational time was confirmed. By using the constructed numerical analysis model, the influence of various process parameters such as input direction of the steel wire, initial diameter of the steel wire, back tension and intermesh on the straightness was confirmed. The simulation result shows that the 3^rd and 4^th roller of vertical straightener had a significant influence on vertical shape of the steel wire.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 춘계학술대회논문집
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• pp.127-130
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• 2003

Electrolytic polishing is the anodic dissolution process in the transpassive state. It removes non-metallic inclusions and improves mechanical and corrosion resistance of stainless steel. Electrolytic polishing is normally used to remove a very thin layer of material from the surface of a metal object. An electrolyte of phosphoric, sulfuric and distilled water has been used in this study. In the low current density region, there can be found plateau region and material removal process and leveling process occur successively. In this study, an electrochemical polishing process using pulse current is adopted as a new electrochemical polishing process. In electrochemical machining processes, it has been found that pulse electrochemical processes provide an attractive alternative to the electrochemical processes using continuous current. Hence, this study will discuss the electrochemical polishing processes in low current density region and pulse electrochemical polishing.

• 소성∙가공
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• 제12권4호
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• pp.388-393
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• 2003

Electrolytic polishing is the anodic dissolution process in the transpassive state. It removes non-metallic inclusions and improves mechanical and corrosion resistance of stainless steel. Electrolytic polishing is normally used to remove a very thin layer of material from the surface of a metal object. An electrolyte of phosphoric acid 50% in vol., sulfuric acid 20% in vol. and distilled water 30% in vol. has been used in this study. In the low current density region, there can be found plateau region and material removal process and leveling process occur successively. In this study, an electrochemical polishing process using pulse current is adopted as a new electrochemical polishing process. In electrochemical machining processes, it has been found that pulse electrochemical processes provide an attractive alternative to the electrochemical processes using continuous current. Hence, this study will discuss the electrochemical polishing processes in low current density region and pulse electrochemical polishing.

• Tribology and Lubricants
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• 제35권6호
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• pp.369-375
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• 2019

This paper presents a new method on how to calculate the thrust forces acting on an auto-leveling device in headlamps for passenger vehicles. The leveling device is used to lower the angle of lights when a load in the trunk of the vehicle lifts it. In the process of the headlamp design, it is imperative to predict the external forces so that the designers can decide whether to proceed or not. The device is composed of three pivot joints with no reaction moment, a plate that holds the lamp, and a leveling motor that changes rotation to linear motion. In this study, force balance, moment balance, and geometric compatibility are applied to the leveling device system so that a nonlinear system of equations can be derived; the multi-dimensional Newton-Raphson algorithm is then used to solve these. A sensitivity analysis is carried out to verify which design variables affect the system the most: the mass of the lamp and the height between the pivot and leveling device affect the thrust forces the most. Then, considering the friction forces between the moving parts, the hysteresis of the forces are derived. An experimental apparatus, designed and developed in this study, is used to verify the exactness of the derived equations. The results from experiments coincide well with the calculated results. The friction hysteresis, in particular, proves this upon analysis.

• Journal of Ship and Ocean Technology
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• 제10권2호
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• pp.37-44
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• 2006

The erection in shipbuilding is the process to assemble all the blocks one by one in certain order and requires more leveled and efficient schedule than other processes do. However, erection schedule includes too many constraints to be systemized with simple programs and constraints are changed frequently. These difficulties make it rare to find automatic erection schedule generation system with load leveling ability. In this paper, a CSP (Constraint Satisfaction Problem)-based load leveling algorithm using a maximum load diminution technique is proposed and applied to the block erection scheduling of a dock in a shipyard. The result shows that it performs better than currently used scheduling method based on empirical logics. The maximum load of welding length and crane usage are reduced by 31.63% and 30.00% respectively. The deviation of resource usage amount also decreases by 8.93% and 7.51%.

• 대한임베디드공학회논문지
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• 제12권3호
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• pp.185-192
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• 2017

Due to the characteristics of low power, high durability and high density, NAND flash memory is being heavily used in various type of devices such as USB, SD card, smart phone and SSD. On the other hand, because of another characteristic of flash cell with the limited number of program/erase cycles, NAND flash memory has a short lifetime compared to other storage devices. To overcome the lifetime problem, many researches related to the wear leveling have been conducted. This paper presents a method called a TCB (Tracking Cold Blocks) using more reinforced constraint conditions when classifying cold blocks than previous works. TCB presented in this paper keeps a MCT (Migrated Cold block Table) to manage the enhanced classification process of cold blocks, with which unnecessary migrations of pages can be reduced much more. Through the experiments, we show that TCB reduces the overhead of wear leveling by about 30% and increases the lifetime up to about 60% compared to BET and BST.