• Proceedings of the Korean Nuclear Society Conference
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• 1997.05b
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• pp.427-432
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• 1997

Boron neutron capture therapy(BNCT) is a binary treatment modality that can selectively irradiate tumor tissue. More is known now about the radiation biology of BNCT, which has reemerged as a potentially useful method for preferential irradiation of tumors. We design a square reactor (that can easily be reconfigured into polygonal reactors as the need arises) with four slab type assemblies to produce high quality epithermal neutron beans and thermal neutron beams jot use in neutron capture therapy. With a low operating power of 300kW, the heat generated in the core can be removed by natural convection through a pool of tight water. The proposed design in this study could be constructed for a dedicated clinical BNCT facility that would operate very safely.

• Journal of Navigation and Port Research
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• v.43 no.2
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• pp.79-85
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• 2019

Climate change is a very vital issue that can be no longer avoided. Korea has been a top-level country Iin dealing with carbon dioxide emissions since 1960. Many studies have been conducted to suppress or eliminate carbon dioxide emissions, which account for a large portion of greenhouse gases. Carbon Capture and Storage (CCS), the most practical method of them, plays a significant role. However, these methods have the disadvantage of the limits of geographical distribution and high possibility of re-emission into the atmosphere. Recently, ocean storage has been studied using Accelerated Weathering of Limestone (AWL), a technique for storing carbon dioxide in the ocean as an alternative to CCS, an underground storage. AWL is a method of converting carbon dioxide into concentrated water in the form of bicarbonate ion and discharging it to the ocean to dilute and store it. It does not cause re-emission to the atmosphere, and the discharged concentrated water increases the alkalinity of the ocean to prevent marine acidification. The objective of this study was to understand the behavior of DIC (Dissolved Inorganic Carbon) including carbon dioxide during the ocean discharge of bicarbonate ion concentrated water in AWL method. This study area was set near Ulleung-do where sufficient water depth and operational efficiency were secured. CORMIX model was used to calculate the material diffusion by submerged discharge using ship.

• International Journal of Naval Architecture and Ocean Engineering
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• v.13 no.1
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• pp.178-186
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• 2021

The wave power extraction by multiple Wave Energy Converters (WECs) deployed in a Y-shaped Water Channel Resonator (WCR) has been investigated. A WCR consists of a long water channel, and a V-shaped wave guider installed at the entrance of a water channel. If the period of the incident waves coincides with the natural periods of the fluid in a WCR, resonance occurs, as a result, the internal fluid in a WCR is greatly amplified. To estimate the wave power by multiple WECs placed at the antinodal points in a WCR, the heave motion response, time-averaged power, and capture width ratio were calculated for several design parameters. Also, the systematic model tests were conducted in a 2D wave tank. The numerical results are in good agreement with the experimental data. It was verified that a WCR helps the WECs to produce electricity more effectively by amplifying the wave energy in a WCR.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.10
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• pp.1071-1080
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• 2020

This study aims to explore the critical success factors of the Water Public-Private Partnership (PPP) Projects in developing country with evidence from Indonesia. We all know that water is a basic need and therefore it becomes very important for the governments especially in the developing countries to develop and formulate a comprehensive water policy to deliver and manage the water services in the most appropriate manner as well tackle several challenges such as budget and project efficiency. In this context, PPP is a promising scheme to address the water problems, hence it becomes important to reveal the success factors of water PPP projects. An Analytic Hierarchy Process (AHP) questionnaire built from delphi methods is used to capture the perception of the relevant stakeholders in relation to the success factors. The results of this study show the most critical success factors in PPP water projects is the support and acceptance of the stakeholders from the community, whereas the private and public entities are the the second and third important factors. These findings contribute to the success of the PPP stakeholders by enhancing the policy-making decision process and by executing the water policies to support the development of PPP in the Water Sector.

• Clean Technology
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• v.19 no.4
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• pp.437-445
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• 2013

To develop SEWGS (sorption enhanced water gas shift) system using dry $CO_2$ absorbent for pre-combustion $CO_2$ capture, hydrodynamic characteristics of $CO_2$ absorbents were measured and investigated. The minimum fluidization velocity of $CO_2$ absorbent was measured and the effects of the operating conditions were investigated to operate the system at bubbling fluidized bed condition. The minimum fluidization velocity decreased as pressure and temperature increased. Moreover, the minimum fluidization velocity decreased as column diameter increased. The effects of operating conditions on the solid circulation rate were measured and investigated to select appropriate operating conditions for continuous $CO_2$ capture and regeneration. The measured solid circulation rates were ranged between 10 and 65 kg/h and increased as the solid injection velocity, gas velocity in the regeneration reactor, and solid height increased.

• Clean Technology
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• v.27 no.3
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• pp.255-260
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• 2021

A drawback in the CO₂ capture process using an aqueous amine solution is the high energy requirement for the regeneration process. In order to overcome this disadvantage, this study investigated CO₂ capture characteristics using a biphasic absorbent in which isopropanol (IPA) was introduced into an aqueous solution of diethylenetriamine (DETA). When the IPA composition exceeded 20 wt% in 20 wt% DETA aqueous solution, the absorbent phase was liquid-liquid separated into a CO₂-rich phase and a CO₂-lean phase because of the low solubility of the salt formed by the reaction of CO₂ with DETA in isopropanol. When the isopropanol composition in the DETA aqueous solution increased, the phase volume ratio of the CO₂-rich phase to the volume of the CO₂-lean phase increased; and, accordingly, the CO₂ in the CO₂-rich phase was more concentrated. The results of absorbing CO₂ in a packed tower using 20 wt% DETA + IPA + water absorbent confirmed that both the CO₂ absorption capacity and the absorption rate were higher than that of the 20 wt% DETA aqueous solution. When a biphasic absorbent composed of DETA + IPA + water is applied to CO₂ capture, it can be expected to concentrate CO₂ because of phase separation and thereby reduce regeneration energy owing to volume reduction of the CO₂-rich phase.

• Environmental Engineering Research
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• v.15 no.4
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• pp.231-237
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• 2010

With increased chemical and economic development activities in upstream areas, the amounts of pollutants released have increased, and as such, so has the need for positive management of water supply source areas. Although more than 90% of the water supply sources in Korea depend on direct intake from surface water, the interest in indirect intake, such as riverbank filtration water, has recently risen, with some local governments currently undertaking indirect intake. Even in cases of indirect intake, water supply source protection zones need to be assigned for the comprehensive control of pollutants. To establish water quality protection zones for indirect intake, the scope of the protection zones needed to reflect the hydrological features of the water-bearing deposits of each site. Water source protection areas were estimated and presented as the 1st (within a 100 m radius from an intake well) and 2nd (within a 2 km radius from an intake well) zones. The 1st zone was more sensitive; hence, the installation of various facilities should be prohibited, and the area should be regarded as off-limits. For the 2nd zone, appropriate management should prohibit and restrict activities already present in the water source protection zone.

• Transactions of the Korean hydrogen and new energy society
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• v.8 no.4
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• pp.155-160
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• 1997

Generation of hydrogen and oxygen gas from water is mostly accomplished by electrolysis. In this report, a scheme is presented regarding the gas generation based on plasmolysis. Unlike electrolysis water dissociation by electrical discharge (plasmolysis) requires a high voltage to cause either electron emission or electron capture, and subsequent ionization of involved molecular species. When electrical discharge is initiated between electrodes separated by water-vapor interface, a very large electric field(~100kV/cm) is developed at the tip of the electrode placed in the vapor phase. It is found that the efficiency of plasmolysis depends on the polarity of the electrode placed in the vapor phase. Also presented is the scheme of hydrogen and oxygen generation by such electrical discharge.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.2
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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.

• Korean Management Science Review
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• v.31 no.3
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• pp.95-111
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• 2014

It is essential to carry out an economic analysis on public water supply projects so that policy makers and water enterprises are aware of the actual value of the project. However, many popular approaches based on discounted cash flow analysis do not capture the uncertainties inherent in cash flow. In order to analyze the economic values of the water supply project of local governments, we utilize real option model, which considers uncertainty in future water price behavior and captures the value of real life flexibility. The real option model is designed to incorporate the option to expand and abandon, and it is applied to a local government case. Furthermore, we assess the project by exploring Luehrman's option space to accommodate the more efficient decision making. The results show that substantial amount of potential value is included in the public water supply service, and the overall value is greater than the value obtained from the discounted cash flow model.