• 한국건축시공학회지
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• 제11권6호
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• pp.557-566
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• 2011

The surfactants facilitate the formation of foam bubbles under a proper condition and provide stability of foam bubbles by decreasing the surface tension of solutions and increasing the viscosity of foam surface. However, there have been almost no practical data of foam concrete in this regard so far. This study aims to understand the effects of foaming agents such as anionic synthetic surfactant and anionic natural material surfactant on the low density foamed concrete. From the experiment, the vegetable soap of anionic natural material surfactants showed a higher foaming rate, more open pores, slightly lower compressive strength, and a higher permeability coefficient compared to the vegetable soap of anionic synthetic surfactants. It is believed that the natural material surfactants make not only the surface tension of the solution low but also the viscosity of slurry high.

• 기술사
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• 제43권3호
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• pp.28-33
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• 2010

The related industrial technologies are also being developed in medicine, education, the military, transportation, process management, security management and information technology industries due to a rapid progress in telecommunications technology. The supervisory remote control system is based upon telecommunications technology. The supervisory remote control systems are used in various ways such as city gas, water supply and drainage, environment, power, communication and device control fields. The supervisory remort control system became a solution with complex systems and important technologies in electricity, city gas filed that require safety management skills. The supervisory remote control system as a special technology has a lot of practical applications. In this paper, Let me examine the present status of remort control system applications and present development plans and alternatives in city-gas industrial technology.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.373-374
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• 2005

NaOCl (Sodium hydrochlorite) have similar smell of chloride and solution of straw color. And boiling point is $110^{\circ}C$, specific gravity is 1.0(50g/l)/1.1(100g/l), Value of pH is 12. NaOCl playa role as bleach, a oxidizer, a germicide, a decolorant, a deodorant, treatment of water supply and drainage, food addition agent because strong oxidation, bleaching, sterilization effect is had. When NaOCl is produced in electrolysis of seawater, this system is composed of injection system by directly electrolysis of salt water on the spot and sodium hydrochlorite generate a safe low concentration(0.4~0.8 %).

• 한국관개배수논문집
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• 제13권1호
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• pp.39-49
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• 2006

Weather station based PET(Potential Evapotrarspiration) analysis has often been inadequate to meet the needs of regional-scale irrigation planning. A map of continuous PET surface would be better a solution for the spatial interpolation considering spatial variations. Using a normal PET data collected at the 54 meteorological stations in Korea, 10-days spatial distribution PET map was created using universal Kriging(UK). These estimation methods were evaluated by both visual assessments of the output maps and the quantitative comparison of error measures that were obtained from the cross validation. The universal Kriging method showed appropriate results in spatial interpolation from weather station based PET to spatial PET with low statistical errors.

• 한국지반공학회논문집
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• 제21권3호
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• pp.133-140
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• 2005

연약지반에서 압밀속도를 가속화시키고 설계 전단강도를 얻기 위하여 선행압밀공법과 병행된 연직배수공법이 널리 사용되어 왔다. 본 연구에서는 배수계가 설치된 연약지반에서 압밀과정 동안에 간극비의 감소로 인한 압축성과 투수계수의 변화를 고려할 뿐만 아니라 1차압밀 동안에 유발되는 2차압밀(혹은 크리프)을 고려할 수 있는 축대칭 비선형 압밀이론이 개발되었다. 측대칭 비선형 압밀해석을 위한 수치해석 프로그램, AXICON은 가정 B를 바탕으로 유한차분법을 적용하여 개발되었다. 가정 A를 바탕으로 한 Hansbo의 해석적인 해와 AXICON 해석결과를 비교$\cdot$분석하였다. 또한 Ska-Edeby 시험성토 현장지반에서 관측된 침하량과 간극수압의 계측자료와 비교하였다. 해석결과에 의하면 가정 A는 현장침하량을 일반적으로 과소 평가하며, 가정 B가 논리적으로 타당하다. 또한 제안된 해석 프로그램을 사용하면 실제 현장의 거동을 잘 예측할 수 있다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제15권4호
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• pp.46-52
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• 2010

Acid mine drainage occurs when sulfide minerals are exposed to an oxidizing environment. The objective of this study was to inhibit the oxidation of pyrite by applying various coating agent such as $KH_2PO_4$, MgO and $KMnO_4$ over its surface as an oxidation inhibitors. Experiments were conducted for 8 days to test the feasibility of oxidation inhibitors. The optimal condition of coating agent for standard pyrite and IK mine was the combination of 0.01M $KH_2PO_4$, 0.01M NaOAc and 0.01M NaClO. Otherwise, for YD mine the combination of 0.01M $KMnO_4$, 0.01M NaOAc and 0.01M NaClO. The $SO_4^{2-}$ reduction efficiency of pyrite, IK and YD mine samples was 70, 92 and 84%, respectively. For 8 days, no significant increase of $SO_4^{2-}$ from pyrite sample coated with inhibitor was observed. The pH of solution remains in between 4 to 6 for the reaction conditions.

• 대한지하수환경학회지
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• 제6권4호
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• pp.206-212
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• 1999

산성광상배수의 처리를 위한 중화제로서 제강 슬래그의 이용 가능성을 검토하였으며 석회석과의 성능을 비교하였다. 24시간 반응시킨 고정 실험에서는 슬래그가 석회석보다 높은 pH를 나타냈고 Fe. Al 및 기타 중금속에 우수한 제거효율을 보였다. 10일간 진행된 연속단계실험결과 역시 슬레그가 석회석보다 높은 pH를 유지하였고 Fe와 Al의 제거성능의 저하는 나타나지 않았으며 Ni, Co. Cu. Zn 모두 석회석보다 슬래그에서 휠씬 높은 제거효율을 보였다. 황산$({H_2}{SO_4})$으로 pH를 AMD와 동일하게 맞추고 중금속만을 인위적으로 첨가한 증류수(인공산 용액)와의 반응에서는 AMD와의 반응에서보다 중금속의 제거효율이 떨어졌는데, 이는 AMD내에 존재하는 Fe와 Al 산화물이 침전할 때 공침이나 흡착에 의해 중금속이 제거되는데 비해 인공적인 AMD에서는 이러한 효과가 없기 때문인 것으로 판단된다. 슬래그의 크기별(5mm이하. 5~20 mm. 20 mm이상)실험에서는 슬래그의 크기가 작을수록 더 높은 pH 상승과 더 효과적인 금속들의 제거 성능을 보여 비표면적이 중요한 요인임을 제시하였다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제15권6호
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• pp.29-36
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• 2010

Several mines including Namil, Solim and Jungbong which are located in the Gyeonggi and Kangwon province have been abandoned and closed since 1980 due to "The promotion policy of mining industry". An enormous amount of mining wastes was disposed without proper treatment, which caused soil pollution in tailing dam and ore-dressing plant areas. However, any quantitative assessment was not performed about soil and water pollution by transporting mining wastes such as acid mine drainage, mine tailing, and rocky waste. In this research, heavy metals in mining wastes were analyzed according to leaching method which used 0.1 N HCl and total solution method which used Aqua-regia to recognize the ecological effect of distance from hot spot. We sampled tailings, rocky wastes and soils around the abandoned mine. Chemical and physical parameters such as pH, electrical conductivity (EC), total organic carbon (TOC), soil texture and heavy metal concentration were analyzed. The range of soil's pH is between 4.3 and 6.4 in the tailing dam and oredressing plant area due to mining activity. Total concentrations of As, Cu, and Pb in soil near ore dressing plant area are 250.9, 249.3 and 117.2 mg/kg respectively, which are higher than any other ones near tailing dam area. Arsenic concentration in tailing dams is 31.0 mg/kg, which is also considered as heavily polluted condition comparing with the remediation required level(RRL) in "Soil environment conservation Act".

• 가정∙방문간호학회지
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• 제21권2호
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• pp.110-119
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• 2014

Purpose: The objectives of this study were to identify interventions and to analyze the characteristics of headaches among hospitalized patients with subarachnoid hemorrhage with moderate or severe headaches. Methods: A retrospective review of the electronic medical records of 210 patients who received treatment for subarachnoid hemorrhage was conducted. Data collection was done using a structured headache record sheet. Data analysis was carried out using the PASW 18.0 version program. Results: There were significant differences in number and duration of headaches of headaches according to the presence of vasospasm, increased intracranial pressure, extraventricular drainage, use of hypertonic solution, and hospitalization period (p<0.05). Patients with vasospasm and extraventricular drainage experienced the most severe headache for a duration of 3 to 7 days. Other patients experienced the most severe headache for around 1-2 days. Conclusion: Hospitalized patients with subarachnoid hemorrhage who had vasospasms experienced more headaches and the duration of these headaches were longer. In particular, the assessment and interventions for headaches should increase and be carried out actively during this time because the intensity of these headaches is severe and lasts for 3-7 days. Additionally, we emphasize the need for regular administration of analgesics in order to promote patients' well-being. On the basis of the results of this study,we suggest that evidence-based interventions for the care of headaches among hospitalized patients with subarachnoid hemorrhage should be developed.

• 한국농공학회논문집
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• 제61권4호
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• pp.63-73
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• 2019

Coastal and fishing facilities are gradually deteriorating in function due to the continual accumulation of soil sediments, which has affected local economic activities. Currently, there are many methods to remove soil sediments, but these methods are either a temporary solution or require a repetitive removal of the soil sediments, which is a huge financial burden for the maintenance of the facilities. To solve these problems, this study proposed a non-power soil cleaning system and evaluated field applicability by carrying out field model tests. The conditions for the evaluation focused on the drainage-elapsed time and drainage-outflow velocity according to the water level change in the water tank. In the field test, silty clay and sand were separately installed, and sedimentation soil removal test was practiced. As a result, the system was verified to have a sufficient outflow velocity for the removal of soil sediments. In addition, a generalization equation that can be used in different regions of the tide was suggested in this study. These results will greatly contribute to removing soil sediments in ports and dike gate facilities on the southwest coast. Since the system is an eco-friendly technology that does not require additional energy, thus it is expected to contribute to maintenance of sustainable facility performance as well as economic effect in the future.