• Transactions of Materials Processing
• /
• v.8 no.1
• /
• pp.65-77
• /
• 1999

In recent years, the quality requirements from the customers of hot rolled steel strip have been steadily increasing in diversity and strictness. To meet these quality requirements as well as to improve productivity, steel mills have been doing their efforts for developing high performance Automatic Gauge Control (AGC) system. However, it is very time consuming and also needs a lot of money to develop the new technologies of AGC in actual mill. So, there has been a demand for developing the Dynamic Hot Rolling Simulator since late 80's. It is a kind of software packages and can analyze the dynamic behaviors of hot finishing rolling process without laborious experiments in actual mill. It can also be used as a designing tool of Automatic Gauge Controller. In this work, the Dynamic Hot Rolling Simulator which is applicable to 6 sands hot strip mill rolling was developed. The MATLAB with SIMLINK was used as a software developer for making the main part of simulator because it is very powerful tool for modeling, integrating, controller design, and simulation. In this paper, the structures and the mathematical models of the simulator were briefly described and the results of simulation on the transient phenomena of hot rolling process with actual mill data were also presented.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2004.04a
• /
• pp.34-41
• /
• 2004

The purpose of this paper is to look at the characteristics of surface finishing which is one of the form accuracies and to obtain the fundamental technical data from the process of machining with diamond tool through experiment and theoretical analysis. The experiments were conducted with domestic made ultra-precision machine and MCD.PCD tool, with aluminum alloyed material and brass being used for the work pieces. The goal of the size accuracy was set to 100nm. The most suitable tool nose radius and machining conditions were selected, and the variations of the surface roughness were observed using SEM method while machining the distance of up to 500km. These data were evaluated and they examined the variation of the machined surfaces while cutting up to 500km of machining distance. At the same time, the state for the wear of diamond tool nose was analyzed and carefully examined through the newest measuring device. Additionally, the characteristics of ultra-precision machining technology were studied through visual analysis.

• Textile Coloration and Finishing
• /
• v.16 no.4
• /
• pp.10-18
• /
• 2004

In this work, Aqueous sericin solution was prepared by degumming process with electrolytic reduction water. Then, the microfiltration and ultrafiltration systems were applied to the concentration of aqueous sericin solution. The objective of this study was to select the optimum operating condition among the different pressure. The permeate flux and rejection ratio were observed with time, pressure, flow rate and concentration. and, the wastewater and permeated water quality values such as pH, BOD, COD, and NH levels were measured. In order to see the influence of electrolytic reduction water, the flux of pure water and electrolytic reduction water by PVDF22(MF) and PS100(UF) membrane was measured. In microfiltration system, the relative flux reduction decreased rapidly to 0.02 in the 30min, as the concentration polarization and gel layer formation were increased. and then the sericin concentration rejection ratio was 40%. In ultrafiltration system, the permeate flux decreased with time and concentration, and increased with the operating pressure and flow rate. Optimal condition in PS100 membrane system for sericin concentration was operating pressure 1.464kgf/$cm^24, operating flow rate $7\ell/min at\; 40^{\circ}C$. At that time, sericin concentration rejection ratio was 83% respectably. The sericin solution was concentrated from 0.1wt% solution to 0.2 wt % solution during about 2 hrs by the UF filteration membrane system.

• Textile Coloration and Finishing
• /
• v.22 no.2
• /
• pp.110-117
• /
• 2010

Recently, there is a trend to utilize natural dyes in many dyeing fields. In this work, the effects of benzyl alcohol in human hair dyeing with cochineal, a natural dye, was investigated. We investigated the K/S value and color value of dyed hair, water retention of dyed hair, protein release-ability of dyed hair, and wash fastness of dyed hair according to dyeing time and temperature. The shade of dyed hair was reddish. By adding benzyl alcohol in cochineal dyeing, the dyeing rate was increased and the dyeing equilibrium was established at early stage. The water retention of dyed hair was increased and the protein release-ability of dyed hair was decreased, meaning that the hair was less damaged during dyeing, The dyed hair showed a good wash fastness.

• Textile Coloration and Finishing
• /
• v.17 no.3 s.82
• /
• pp.34-42
• /
• 2005

In this work, a practical separation performance was investigated on aqueous alcohol solutions, especially for iso-propyl alcohol (IPA), which is usually used during the semi- conductor rinsing process. The removal of various substances from waste aqueous IPA solutions was carried out by microfiltration with $0.1\~1{\mu}$m pore size of mean diameter as a pre-filter. Permeability and molecular weight cut-off of the functional polysulfone(PSf) ultrafiltration membrane to purify waste aqueous IPA solutions were measured through the ultrafiltration test. The solute rejection of PSf membrane had $92\%$ in 1,000ppm aqueous PEG solution with PEG molecular weight 10,000, the molecular weight cut-off had 10,000. The IPA concentration on the $CMPA-K^+$ membrane performance using pervaporation module system could be increased from $95.04 wt\%$ to more than $98.50wt\%$ in about 9hr at operation temperature of $70^{\circ}C$ using the pervaporation module system.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2016.05a
• /
• pp.127-129
• /
• 2016

근래 소규모항만이 흩어져 있는 연안도서해역에서는 빈번한 폭풍의 내습으로 신규 외곽시설을 포함한 항만정비사업이 지속적으로 이루어지고 있다. 이들 항만의 경우 늘어나는 물동량에 대응하기 위해 수역시설 및 부두의 배치에 변화를 가져오고 일부 항만의 경우 만입구, 항내, 수로 등 특정해역의 준설이 다양하게 이루어지고 있어서 개발과 유지 준설에 따른 정온도의 검토가 필요한 실정이다. 본 연구에서는 바람, 파랑상호간 간섭, 흐름과의 상호작용, 쇄파 및 구조물에 대한 반사를 반영하여 수치실험을 수행하고 특히 준설작업의 규모, 방향에 따른 정온도에서 결과에 차이를 나타내어 평면배치계획에 수정을 기할 수 있게 되었다. 수치실험에는 50면 재현빈도 심해설계파 내습시 영역을 광역, 중간역, 상세역으로 하여 네스팅 기법으로 개방해역조건을 반영하였으며 외곽시설에서 해수소통 개구부의 변화에 대한 영향을 분석하였다.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.20 no.7
• /
• pp.2257-2265
• /
• 1996

In the cold rolling mill, it is very important that a constrained static flow stress of rolled strip and rolling force calculation model be exactly considered to improve an prediction accuracy for rolling forces. Therefore, in this study, the values of the constrained static flow stress are used by deriving the regression equation which is a function of rolling conditions(FDT, CT) and chemical compositions(C, Si, Mn), previously applied by making the tables of yield strength for hot coils with size. And with the consideration that an elastic deformation part of an rolled strip appears at the entry and delivery side of the contacting area between the work roll and rolled strip is calculated. By applying these methods, the more accurate prediction for rolling force is obtained. As a results, the deviation of thickness is significantly reduced in the rolling direction.

• Textile Coloration and Finishing
• /
• v.25 no.1
• /
• pp.56-64
• /
• 2013

In order to examine the availability of color developing for prepared persimmon extract powder dyes, purified and freeze-dried powder from immature persimmon fruit. The cotton fabrics dyed with 1% concentration of powder dyes. This study was conducted to examine into the color developing effects of the powder dye for the dyed cotton fabrics irradiated with xenon light. Powder dye is difficult to dissolve in water resulting in a colloidal and viscous solution. The problem of solubility in water was resolved by setting the dyeing conditions by wetting the dye with alcohol in advance and dissolving in warm water($50{\sim}60^{\circ}C$). Samples had no alkaline conversion in making process of powder dyes showed high color developing effect(${\Delta}E^*$, K/S). Samples showed decreased ${\Delta}E^*$, K/S with increased alkaline conversion in making process of powder dyes. Samples that had alkaline effects displayed easy early color developing to be advantageous in the process of natural pattern in art work.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.25 no.12
• /
• pp.11-20
• /
• 2011

PSALI is referred to the supplementary lighting for the interior lighting under the daily lighting situation, and pursuant to the pertinent regulations in energy savings design standard and others in recent architecture works, the importance thereof has been increasing gradually coupled with the energy performance index (EPI), energy savings plan and the like as well as expansion of submittal and implementation policies. However, this type of PSALI studies indeed have a number of limitations since it has surrounding environmental conditions in direction, season, region, climate, time, opening rate, window area ratio, actual index, reflection rate of finishing materials and others in the architecture work as well as frequent changes in interior lighting environment for variables in daily light volume flowing into the interior, and others. Therefore, this study has analyzed existing advance research cases to produce the actual-sized model and scaled-down model, and installed the artificial lighting of LED light source possible to reproduce with same capability on both models. As a result of comparison and analysis of the artificial lighting with the key light, it has certain level of error rate from the scaled down lighting device in certain rate and actual model butit was noticeably significant within specific scope.

• The Journal of the Acoustical Society of Korea
• /
• v.21 no.2E
• /
• pp.81-90
• /
• 2002

Single absorbing materials and Helmholtz resonators have limited absorption characteristics over limited frequency ranges due to their structures and properties. Porous materials are highly absorptive for mid and high frequency ranges, while they have little sound absorption for low frequency sounds. Helmholtz resonators are generally used to absorb sound energy for a specified frequency range. Hence they have limited capability in controlling the overall acoustic properties of a space. Not much has been known about useful finishing materials which have enough rigidity and absorption over broad frequency range, in spite of wide demands from acoustic designers and consultants. The present work measured and analyzed absorption characteristics of a slit absorber by varying surface materials, depths of air gap, dimensions of slat and slit widths. It was found that the narrower the slit width, the larger the absorptions over the wide frequency ranges and the pattern was dependent on the presence of porous material. Narrower slat's width tend to increase the slit absorber's absorption more or less. Absorption coefficients at low frequency ranges were dramatically improved (from 0.23 to 0.56) by increasing air gap when porous materials were present.