• 한국건설관리학회논문집
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• 제5권5호
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• pp.101-108
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• 2004

A construction process consists of value adding activities and non-value adding activities, necessary or unnecessary. If construction personnel can eliminate inefficient and/or unnecessary activities within the process, they may have a great opportunity to improve their construction process. The Product Process Analysis (PPA) technique, which was developed in the manufacturing industry, can be applied for identifying wastes in the construction process and ultimately improving the process itself. It provides useful tools, such as a process chart worksheet and flow diagram, for mapping the flow of construction activities with predetermined standardized symbols. These tools make people understand the flow of activities more easily, identify value adding/non-value adding activities within the process, and areas where the process can be improved. The example applications of PPA are demonstrated in the paper through the case studies implemented on the construction process of structural steel. The results of case studies indicate that PPA technique was effective at identifying and removing wastes in the steel construction process. It is also found that PPA technique is more effective for improving highly repetitive construction processes.

• 한국응용과학기술학회지
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• 제17권3호
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• pp.167-173
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• 2000

The process variables for the manufacture of translucent microemulsion prepared with 2-octyl dodecanol, 12-hydroxy stearic acid cholesteryl , POE(40)HCO and 1,3-butandiol were examined initially (primary emulsion) and following aging for three months. The techniques empolyed in this study were particle size, turbidity, interfacial tension and microfluidizer. Particle size analysis and turbidity measurement to evaluate the emulsion stability were used. It was concluded that the process of the emulsification was an important indicator of the stability of the translucent microemulsion. From the particle size and and turbidity measurement of translucent microemulsion, adding the surfactant to the oil phase before the emulsification was found to be the most important factor for the stability of emulsions. We found that interfacial tension of the adding the surfactant to the oil phase is lower than that of the adding the surfactant to aqueous phase. In spite of hydrophilic surfactant, adding the surfactant to aqueous phase produced inferior emulsion to that to oil phase.

• 한국의류산업학회지
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• 제10권6호
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• pp.822-826
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• 2008

The data for application of mordanting is shown in this experiment by researching dying properties of iron-dye process and concentration changes using persimmon. The strength of persimmon-dying fabrics was controlled by diluting persimmon dye with water and iron mordanting showed the possibility of textile design. The experiments were performed with various conditions processed with iron mordanting liquid by adding water to persimmon-dying liquid and drying well. The most dark color of fabric is observed with the pure persimmon dying without adding water. As the adding water is increased, the color of the fabric is getting lighter with the amount of adding water. After process of iron mordanting, dark color of the fabric turns into dark grey and light color turns into light grey. The possibility of persimmon dying with fabric can be applied in the design of textile with deepened color.

• 한국세라믹학회지
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• 제21권2호
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• pp.143-148
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• 1984

In this study we mainly dealt with the effects of organic retarder(calcium lignosulfate) on the early hydration process of clinker minerals. From a consideration of the hydration process of tricalcium silicate $(C_3S)$ tricalcium silicate $(C_3S)$-tricalcium aluminate $(C_3A)$ tricalcium silicate $(C_3S)$-tetracalcium aluminof-errite $(C_4AF)$ systems with calcium lignosulfate the following results were obtained. 1. when 0.25wt% of CLS was added to $C_3S$ the hydration process was progressed normally but adding of 0.5wt% its hydration was greatly retarded. 2. The hydration of $C_3S$-$C_3A$ system was progressed normally up to 0.5wt% but by adding gypsum its hydration was retarded slightly. 3. The hydration of $C_3S$-$C_4AF$ system was greatly retarded even with 0.25wt% of CLS but by adding gypsum its hydration process was recovered normally.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2001년도 학술대회지
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• pp.416-421
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• 2001

국내 철근 콘크리트 공사는 철근현장가공조립을 주로 하고있는데 철근공사는 거푸집공사와 더불어 건축물의 구조적 안정성과 내구성 및 공기에 가장 큰 영향을 미치고 있는 공사이다. 이와 같은 철근현장가공조립의 프로세스를 린 생산원리를 적용하여 가치흐름분석을 하였다. 가치흐름분석은 가치분석과 가치흐름맵핑을 통해서 건설프로세스 상의 가치창출작업과 비 가치창출작업을 분석하였다 그 결과 비 가치창출 작업으로 인한 낭비로 많은 작업 단계와 인력, 장비, 자재, 시간 등이 낭비되고 있었다. 또한 밀어내기 생산(Push-driven Production)으로 과잉생산을 하는 등 생산의 낙후성이 조사되었다. 이러한 프로세스상의 문제점을 개선하기 위해 이 연구에서는 부가가치를 창출하는 가치창출 작업을 최대화하고, 비 가치창출작업을 최소화하여 낭비요소를 제거하는데 목적이 있다. 특히 진행간 재고를 최소화하여 흐름생산(Flow Production)과 당김생산(Pull-driven Production)이 될 수 있도록 하였다.

• 환경위생공학
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• 제13권2호
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• pp.95-105
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• 1998

This research was investigated which denitrification of wastewater containing nitrate, using upflow anaerobic sludge blanket process. The upflow anaerobic sludge blanket process is also used for both artifical and industrial wastewater. Main ingredients investigated in the artifical and industrial wastewater experiment were the determination of optimum organism/nitrate ratios, nitrate removal efficiency by various hydrogen donor addition and characteristics of granular sludge and gas production in case of various hydrogen donor addition. From the experimental results the following conclusions were made: In case of adding methanol, ethanol and sodium acetate as hydrogen donor granular sludge was formed 50 days after seeding. Average diameter of granular sludge was 4.0 mm and settling velocity was 37 cm/min. Production rate of gas 3.3 L/d in case of adding methanol as hydrogen donor in wastewater containing 150mg/L nitrate. However adding ethanol and sodium acetate as hydrogen donor, gas production rate were 2.2-2.7L/d respectively. In case of adding methanol as hydrogen donor treatability of artifical wastewater contained 150mg/L as nitrate was about 93%. But in addition of sodium acetate in wastewater contained 40mg.L as nitrate, nitrate removal efficiency was 80%.

• 한국건설관리학회논문집
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• 제3권4호
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• pp.93-103
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• 2002

철근공사는 거푸집공사와 더불어 건축물의 구조적 안정성과 내구성 및 공기에 가장 큰 영향을 미치고 있는 공사이다. 그러나 국내 철근 콘크리트 공사는 철근현장가공조립을 주로 하고있어 낮은 생산성을 갖고 있는 실정이다. 따라서 본 논문은 생산성 향상을 위해 철근현장가공조립 프로세스를 부가가치 생산성향상을 위한 낭비요소를 분석하였다. 낭비요소 분석은 비가치창출 작업으로 인해 발생하는 요소로 철근현장가공조립의 가치분석을 통해 부가가치를 극대화 하고자 하였다. 그 결과 가치창출작업들이 비가치창출 작업보다 월등히 적다는 것으로 분석되었다. 특히, 본 논문에서 낭비는 불필요한 작업 단계와 인력, 장비, 자재, 시간 등에서 낭비되고 있었다. 또한 흐름생산이 되지 않고, 과잉생산을 하고 있는 것으로 조사되었으며, 가치의 변화가 필요한 것으로 분석되었다. 본 논문에서는 부가가치 생산성 향상을 위해 프로세스 상에 내재되어 있는 낭비요소를 분석하여 부가가치를 창출하는 가치창출 작업을 최대화하고, 비 가치창출작업을 최소화하는데 목적이 있다.

• 한국세라믹학회지
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• 제32권6호
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• pp.719-725
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• 1995

ZST powders were synthesized by coprecipitation of (Zr4+, Ti4+)-hydroxide in the presence of SnO2 particles. Zn(NO3)2 was used as a sintering additive, and according to the adding sequence, sintering and dielectric properties were investigated. Sintered densities of ZST prepared by adding Zn(NO3)2 before calcination were a little higher than those added after calcination, and dielectric properties of the specimen added by Zn(NO3)2 after calcination were better (sintered at 125$0^{\circ}C$/2 h ; Q$\times$f(GHz)=49, 000, $\varepsilon$r=41) than before calcination (Q$\times$f(GHz)=42, 000, $\varepsilon$r=39.5). Through the observation of TEM, it was identified that the cause was due to the difference of the degree of Zn2+ diffusion into grains. With increasing sintering time from 2 to 8 hrs, grain size was doubled and dielectric properties were somewhat deteriorated.

• 상하수도학회지
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• 제22권3호
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• pp.373-378
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• 2008

The pH & alkalinity adjustment method by lime and carbon dioxide($CO_2$) for corrosion control in water distribution system was investigated to determine the optimum operational condition in lime adding process in water treatment plant(WTP). The mixing time at dissolution tank and sedimentation time at saturator for maintaining optimal turbidity condition of lime supernatant were 60~75 minutes and 75~95 minutes, respectively. There was no difference according to $CO_2$ adding methods such as $CO_2$ saturated water or $CO_2$ gas. But, $CO_2$ saturated water could be convenience at WTP in terms of pH control and quantitative dosing. To minimize generation of calcium carbonate products, the short time interval between adding of lime and $CO_2$ is most important. The lime should be added below 32 mg/l for preventing pH rising and generation of calcium carbonate products at the heating condition.

• 한국전기전자재료학회논문지
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• 제16권6호
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• pp.465-470
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• 2003

The chemical mechanical polishing (CMP) process has been widely used for the global planarization of multi-layer structures in semiconductor manufacturing. The CMP process can be optimized by several parameters such as equipment, consumables (pad, backing film and slurry), process variables and post-CMP cleaning. However, the COO(cost of ownership) is very high, because of high consumable cost. Especially, among the consumables, the slurry dominates more than 40 %. In this paper, we have studied the CMP characteristics of diluted silica slurry by adding of raw alumina abrasives and annealed alumina abrasives. As an experimental result, we obtained the comparable slurry characteristics compared with original silica slurry in the view-point of high removal rate and low non-uniformity. Therefore, we can reduce the cost of consumables(COC) of CMP process for ULSI applications.