• 한국수자원학회논문집
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• 제32권1호
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• pp.49-59
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• 1999

우리 나라의 세굴현황을 파악하고 교량설계에 대한 기초자료를 제공하기 위하여 중부지방의 중·소하천에 위치한 교량에 대하여 실시한 세굴조사 자료를 분석하였다. 현장실측은 주로 세굴에 영향을 미치는 물리량들, 즉 수심, 유속, 교각폭, 및 길이, 세굴깊이, 접근각 등을 중심으로 이루어졌다. 지역적으로는 경기도 용인·광주지역, 홍천강의 서면지역, 청평·포천지역, 연천지역, 청주북일지역으로 구분하였으며 교각도 타원과 원형으로 구분하였다. 이들로부터 세굴깊이와 수심, 접근각 도는 Fuoude수 등주요 인자들과의 관계를 도출하였으며 또한 기존의 제안된 세굴공식에 이들을 적용시켜 세굴깊이를 산정하였다. 또한 실측된 세굴깊이와 비교하여 우리 나라에 적용가능한 세굴공식을 제안하였다.

• Wind and Structures
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• 제21권6호
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• pp.625-639
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• 2015

Monopiles have been most widely used for supporting offshore wind turbines (OWTs) in shallow water areas. However, multi-member lattice-type structures such as jackets and tripods are also considered good alternatives to monopile foundations for relatively deep water areas with depth ranging from 25-50 m owing to their technical and economic feasibility. Moreover, jacket structures have been popular in the oil and gas industry for a long time. However, several unsolved technical issues still persist in the utilization of multi-member lattice-type supporting structures for OWTs; these problems include pile-soil-interaction (PSI) effects, realization of dynamically stable designs to avoid resonances, and quick and safe installation in remote areas. In this study, the effects of PSI on the dynamic properties of bottom-fixed OWTs, including monopile-, tripod- and jacket-supported OWTs, were investigated intensively. The tower and substructure were modeled using conventional beam elements with added mass, and pile foundations were modeled with beam and nonlinear spring elements. The effects of PSI on the dynamic properties of the structure were evaluated using Monte Carlo simulation considering the load amplitude, scouring depth, and the uncertainties in soil properties.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.71-80
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• 2005

More than 100 bridges have been annually collapsed or seriously damaged by scouring in Korea. It is extremely hard to understand the complicated scour mechanism and estimate the scour depth with accuracy in fields, however since scouring is a very complex manifestation of sediment transport unable to describe with a simple mathematical tool. In order to obtain the reasonable solution to bridge scouring, therefore, the interdisciplinary co-operation is strongly recommended. In this study the special task force team for the scour problems around Incheon 2nd bridge piers is made, in which all kinds of scour oriented researches such as oceangraphic survey, hydraulic model test, numerical simulation, scour rate test, real-time scour monitoring, etc will be carried out. This paper provides this interdisciplinary procedure in details.

• 한국염색가공학회지
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• 제12권1호
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• pp.68-75
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• 2000

In this study, polyester DTY faille(yoryu) and N/NP microfiber fabrics were pretreated (desizing, scouring and shrinking) by Continuous Scouring and Shringking Equipment with rota-drum and conveyor type in which types were different with retaining method. The results were as follows. The shrinkage ratio of wp/wf direction of DTY fabrics scoured by conveyor type was 1.5/23% higher than those by rota-drum type at $97^\circ{C}$ with 10min. treatment. In this case, The shrinkage ratio of wp/wf direction by those types was about 15/27%, respectively. The shrinkage ratio of wp/wf direction of N/NP microfiber fabrics scoured by conveyor type was 1.5/23% higher than that by rota-drum type at $97^\circ{C}$ with 10min. treatment. The size add-on of DTY fabrics scoured at $97^\circ{C}$ with 10min. treatment by conveyor type and by rota-drum type were 0.15% and 0.42%, respectively. The size add-on of DTY fabric treated by rota-drum type decreased until 9min. of treated time, but increased after 9min. The size add-on of N/NP microfiber fabrics treated by conveyor type was decreased by increasing temperature and treated time, while the size add-on of that treated by rota-drum type was decreased until 6min. treated time and increased after 6min. The size add-on of N/NP microfiber fabrics treated by conveyor type at $97^\circ{C}$ for 10min. was 0.3% lower than that by rota-drum type.

• 한국염색가공학회지
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• 제22권3호
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• pp.220-228
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• 2010

This study examines the scouring effect of pectinase on ramie fabric and influence of sodium sulfate as an activator for pectinase. The scouring effects were measured by the weight loss and pectin contents. SEM, weight loss, stiffness, moisture regain and dye ability of ramie fabric teated with pectinase/sodium sulfate were also measured. When ramie fabrics were desized with $\alpha$-amylase, the optimum conditions were pH 6.5 at $60^{\circ}C$ for 80 min with 1%(o.w.f) $\alpha$-amylase concentration. When ramie fabrics were scoured with pectinase, the optimum conditions were pH 8.5 at $55^{\circ}C$ for 30 min with 10%(o.w.f) pectinase concentration. Addition of sodium sulfate improved enzyme activity significantly, which increased proportionally with increasing sodium sulfate concentration. When 50 g/l of sodium sulfate was added, the surface became cleaner compared to the enzyme treatment without salt: weight and tensile loss, moisture regain and dyeability of the treated fabrics increased, while pectin contents and stiffness decreased. Therfore, sodium sulfate was effective activator for the pectinase treatment of flax fiber.

• 상하수도학회지
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• 제29권2호
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• pp.251-259
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• 2015

The main objective of this research is to study feasibility for applying metal membrane to remove particles from air scouring membrane backwash water. Also, the research was conducted to investigate the influence of polyamine coagulation on floc growth in membrane backwash water as pretreatment for removal particles. From the results of experiments for evaluating the influence of polyamine coagulation on floc growth, it was investigated that particles in the rage of $2{\sim}50{\mu}m$ grew up to $30{\sim}5,000{\mu}m$. In addition, all six metal membranes showed lower removal efficiency, which was 0.87~13.89%, in the case of no polyamine coagulant. On the other hand, in the case of injecting polyamine coagulant, those did extremely high efficiency in 56~92%. From the SEM(Scanning Electron Microscope) images of filtered wiremesh and metal foam membrane, sieve effects were predominant for liquid solid separation in wiremesh and adsorption and diffusion capture effects were predominant in metal foam membrane.

• 한국염색가공학회지
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• 제18권6호
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• pp.43-48
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• 2006

Electrolytic water(EW), studied in recent decades in the Japan, Russia and United State of America, have shown promise as a method of disinfection whereby low levels of free chlorine, sodium hypochlorite, or hypochlorous acid may be produced in situ in Nacl-containing solution. These methods have shown promise in destruction of microorganisms in medical, dental environment, and in the agriculture and food industry. A recently EW treatment system was evaluated for reducing scouring agent and other surfactants in the washing and scouring process of textile industry Unfortunately, there is, to my knowledge, no serious studies of the properties of EW for textile industry In order to study the characteristics of EW and confirm the possibility of applications in textile industry processes, the pH, surface activity, penetration force, surface tension, and contact angle of EW was measured under various conditions. In general terms, What all this shows is that there is fundamental difference between the properties of EW and that of distilled water.

• 한국산학기술학회논문지
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• 제19권9호
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• pp.20-29
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• 2018

최근 기후 및 홍수사상이 변화함에 따라 하천제방 붕괴 및 범람으로 인한 수재해 위험성이 증가하고 있는 추세이기 때문에 각종 수재해 시나리오에 대응 가능한 하천제방 유지관리 기술을 고도화할 필요가 있다. 본 논문에서는 하천제방의 효율적인 유지관리 및 재해 대응성 향상을 위하여 하천제방 안정성에 영향을 주는 주요 요소별 안전도맵 평가체계를 제안하고자 한다. 하천제방 안전도맵은 활동, 파이핑, 육안점검, 세굴, 제체재료 등의 안전도 지표를 GIS맵 상에 지도형태로 표출함으로써 육안으로 신속하게 위험지역을 파악할 수 있고, 피해발생 이후 피해복구를 실시하는 현 국내 제방관리 수준에서 벗어나 선제적인 대응을 통해 하천제방 유지관리의 효율성을 극대화 할 수 있다. 본 논문은 기 제안된 활동, 파이핑, 육안점검 등을 포함한 하천제방 안전도맵 평가체계에 세굴, 제체재료 등을 추가 및 보완한 후속논문으로서, 1)문헌 및 자료 조사를 통한 세굴 및 제체재료 3등급 기준을 제시하였으며, 시범평가를 통해 2)남강지역 좌안 5개소의 홍수위지속시간에 따른 활동 및 파이핑 특성, 3)남강지역 좌/우안 9개소의 세굴 및 제체재료 특성 등을 평가하였다. 본 논문에서 제안하는 하천제방 안전도맵 평가체계는 향후 하천관리자 행동요령, 보수 보강공법 선정, 소요 예산 산정 등을 연계한 연구가 진행된다면 보다 현실적이고, 활용성 높은 연구가 될 것으로 판단된다.

• 상하수도학회지
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• 제33권5호
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• pp.353-366
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• 2019

This research proposes an optimal flushing operation technique in an effort to prevent secondary water pollutions and accidents in aged pipes, and to improve the cleaning effect of unidirectional flushing. Water flow directions were analyzed using EPANET 2.0, while flushing and air scouring experiments in forward and reverse directions were performed in the field. In 42 experiments, average residual chlorine concentration and turbidity were improved after cleaning compared to before cleaning. It was found that even when the same cleaning method was used, further improvement of cleaning effect was possible by applying air injection and reverse direction cleaning techniques. By means of one-way ANOVA(Analysis of variance), it was also possible to statistically verify the need of actively utilizing air injection and reverse direction cleaning. Based on correlation between turbidity and TSS, the total amount of suspended solids removal was estimated for 874 flushing operations and 194 air scouring operations. The result showed that air scouring used more discharge water than flushing by an average of $4.9m^3$ yet with larger amounts of suspended solids removal by an average of 145.9 g. The result of analysis on turbidity values from 887 flushing operations showed low cleaning effect of unidirectional flushing for the pipes with diameters over 300 mm. In addition, the turbidity values measured during cleaning showed an increasing tendency as pipe age increased. The methodology and results of this research are expected to contribute to the efficient maintenance and improvement of water quality in water distribution networks. Follow-up research involving the measurement of water quality at regular time intervals during cleaning would allow a more accurate comparison of discharge water quality characteristics and cleaning effects between different cleaning methods. To this end, it is considered necessary to develop a standardized manual that can be used in the field and to provide relevant trainings.

• 한국염색가공학회:학술대회논문집
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• 한국염색가공학회 2000년도 추계학술발표회 논문집
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• pp.104-107
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• 2000