• Applied Chemistry for Engineering
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• v.26 no.3
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• pp.259-264
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• 2015

For the enhanced oil recovery, one of the most important factors is to determine the surfactant formulation in chemical flood. The objective of this study is to analyze the microemulsion formed between the alkali-surfactant (AS) solution and A crude oil for screening surfactants. The alkali-surfactant solution was manufactured by using the surfactant purchased from AK ChemTech. $C_{16}-PO_7-SO_4$ and sodium carbonate solution were used as surfactant and alkaline, respectively. Both TEGBE and IBA were used as a co-solvent. The AS solution and A crude oil can form a Type III middle phase microemulsion at the salinity from 0.0 wt%~3.6 wt%. Increasing the salinity causes the phase transition of microemulsion from the lower (Type I) to middle (Type III) to upper (Type II) phase. Interfacial tension (IFT) values calculated by Huh's equation were in good agreement with ultralow IFT. According to this characteristic, the surfactant purchased from a domestic company can be applied to the enhanced oil recovery.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.6
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• pp.453-479
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• 2011

Residual pharmaceutical compounds have been recognized as emerging environmental pollutants and are widely distributed all over the world. These compounds cause bioaccumulation and biomagnification during present for a long time in the environment: thereby after adversely biota and human bodies. It is difficult to remove residual pharmaceutical compounds using conventional water/wastewater treatment because of resistant property to photodegradation, biodegradation and chemical decomposition. Moreover, domestic literature data on the pollution of residual pharmaceutical compounds in rivers and lakes are limited. In this paper, species, sources, fate and risk of residual pharmaceutical compounds as well as behavior properties in freshwater resources are demonstrated to encourage the domestic concern about residual pharmaceutical compounds. An extensive review of existing data in the form of figures and tables, encompassing many therapeutic classes are presented.

• Journal of Wetlands Research
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• v.16 no.2
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• pp.205-212
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• 2014

Ultrasound technology can be applied in various fields including environmental, energy, and material engineering processes. In this study the effect of liquid height/volume on calorimetric energy and sonochemical oxidation was investigated as one of the basic steps for the design of water/wastereater treatment sonoreactors. The liquid height was increased from 0 to $4{\lambda}$ by $1/4{\lambda}$ and it was found that both calorimetric energy and sonochemical oxidation were significantly increased at relatively high liquid height/volume where the power density was relatively low. The sonochemiluminescence (SCL) images for the visualization of the activity of cavitation also showed that larger and more stable active zone was formed with high SCL intensity at high liquid height/volume. Therefore, it was revealed that sonoreactors for water/wasterwater treatment could be significantly effective in terms of removal efficiency and energy consumption.

• Journal of the Korean Geotechnical Society
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• v.18 no.5
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• pp.73-81
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• 2002

Nowadays , the grouted-reinforcing method, which is called FRP(Fiberglass-reinforced-plastic) pipe .reinforcing method, has been introduced in the community of pound reinforcements. The resistance to corrosion and chemical attack high strength to weight ratio, and ease of handling make these pipes a better alternative to steels in tunnel. However, to fully utilize FRP pipes as grouted reinforcing members at the face and the crown in tunnel, their mechanical properties and behaviors and the grout-reinforced underground have to be verified. Laboratory shear tests were conducted to evaluate the mechanical properties for FRP pipes, the grout-reinforced members and the grout-reinforced body of FRP pipes. According to the test results, it was observed that FRP pipes play a dominant role in shearing behavior of the grout-reinforced members and that their shearing resistance exerts after the shearing displacement increases to some extent.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.10
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• pp.774-781
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• 2011

Nitric acid and hydrofluoric acid are used for acid pickling in zirconium alloy tubing manufacturing process. Nitrate and fluoride in the wastewater were treated by chemical coagulation and SOD (Sulfur Oxidation Denitrification) process. This study is investigated the effect of fluoride concentration and the optimal condition for SOD process. The limited fluoride concentration for SOD process was below 20 mg F-/L. The adjusted pH and alkalinity by NaOH and $NaHCO_3$ was shown to be more effective for removal of nitrate compared with using NaOH. Furthermore, the microbial activator mixed trace elements and ingredient for alkalinity did not only supplement with alkalinity but also enhance the growth and proliferation for sulfur-oxidizing bacteria. As a result, the inorganic industrial wastewater was successfully treated by the microbial activator in SOD process without continuous addition of seed sludge. Finally, SOD process was shown to remove nitrate in industrial wastewater and to contribute the microbial activator for activation of sulfur-oxidizing bacteria.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.447-451
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• 2009

최근 들어 하천의 치수와 이수 그리고 환경적 측면을 고려한 "자연형 하천정비공사"가 활발히 이루어지고 있다. 그러나 개별적 특성이 뚜렷한 각각의 하천에서 그 하천을 기반으로 생활하는 생물들의 서식조건을 충분히 고려하였다고 보기는 어려운 상황이며, 제한된 공법의 사용으로 획일화된 인공하천 조성 및 관행적 하도정비에 그쳐 하도서식처가 빈번하게 교란되고 있는 것이 현실이다. 특히, 하천에서의 하도서식처는 하천을 서식기반으로 살아가는 생물들에게 생활사의 각 단계(먹이섭취, 휴식, 피난, 산란, 우화, 번데기)에서 이용하는 특정 장소로서 중요한 의미를 가지며 하천을 복원하는 하나의 목표이기도 하다. 본 연구는 대전에 위치한 갑천을 대상으로 하천을 서식기반으로 살아가는 생물들의 하도서식공간의 유형을 구분하고 각각의 서식처의 물리 화학 생태적 특성을 규명하고, 그 입지에 적응하며 서식하는 생물 상호간 생태적 연관성에 대하여 검토하였다.

• Journal of the Korean Geotechnical Society
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• v.23 no.4
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• pp.5-13
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• 2007

Many construction projects adopt grouting technology to prevent the leakage of groundwater or to improve the shear strength of the ground. Recognition as a feasible field procedure dates back to 1925. Since then, developments and field use have increased rapidly. According to improvement of grout materials, theoretical study on grout penetration characteristics is demanded. Fluid of grout always tends to flow from higher hydraulic potential to lower one and the motion of grout is also a function of formation permeability. Viscosity of pout is changed by chemical action while grout moves through pores. Due to the increment of viscosity, permeability is decreased. Permeability is also reduced by grout particle deposits to the soil aggregates. In this paper, characteristics of new cement grout material that has been developed recently are studied: injectable volume of new grout material is tested in two different grain sizes of sands; and the method to calculate injectable volume of grout Is suggested with consideration of change in viscosity and clogging phenomena. The calculated values are compared with injection test results. Viscosity of new grout material is found to increase as an exponential function of time. And lumped parameter $\delta$ of new grout material to be used for assessing deposition characteristics is estimated by comparing deposit theory with injection test results considering different soil types and different injection pressures. Injection test results show that grout penetration rate is decreased by the increase of grout viscosity and clogging phenomena.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.1
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• pp.105-111
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• 2020

The present study examined the effect of the silica-based accelerating agents on the setting time and compressive strength gain of biomimetic glycocalix coating materials that has been developed for protecting the substrate of concrete exposed to chemical and microbiological attacks. The accelerating agent contents varied from 10mL/L to 40mL/L in the mixtures of glycocalix coating materials determined for shotcrete and lining techniques. Test results showed that the setting time of coating materials containing accelerating agents was affected by the contents of the bacteria carrier. When the accelerating agent content was 40mL/L, the final setting time was 80 minutes for shotcrete mixtures and 318 minutes for lining mixtures. Meanwhile, the compressive strength gain of coating materials with accelerating agents tended to be lower than that of counterpart materials without accelerating agents.

• Journal of the Korean Institute of Gas
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• v.28 no.2
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• pp.7-16
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• 2024

This study presents investigation on the technical characteristics and field cases of the salt cavern storage method for large-scale hydrogen storage. The salt cavern storage method enables effective hydrogen storage compared to other methods due to the low porosity and permeability of the rock salt that constitutes the cavern, which is not likely to leak and requires a small amount of cushion gas for operation. In addition, there is no chemical reaction between rock salt and hydrogen, and multiple injection/withdrawl cycles can be performed making it effective for peak shaving and short-term storage. The salt cavern is formed in three stages: leaching, debrining, and filling, and leakage tests are conducted to ensure stable operation. Field applications are currently performing to meet industrial demand in the surrounding area of four sites in the UK and Texas, USA, and salt cavern operation is being prepared for energy storage in European countries such as Germany and France. The investigated results in this study can be utilized as a basic guideline for the design of future hydrogen storage projects.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.3
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• pp.195-202
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• 2006

Deterioration of sewer concrete is representative that biochemical corrosion according to the $H_2S$ has growth by inhabit sulfur-oxidzing bacteria because of special environment in sewer. But in case of domestic, fundamentally, sulfur-oxidzing bacteria could moderate development of repair material method is need because of corrosion prevent method is inconsideration with carry out to improve project. In this paper, after development of spread type antibiotic with antibio-metal, antibacterial performance about sulfur-oxidzing bacteria of antibiotic and tested to estimate fundamental properties of bonding strength, abrasion contents, contents of water absorption, contents of air permeability, carbonation depth, chloride ion penetration depth and chemical resistance of spread with antibiotic restorative mortar.