• Journal of Electrochemical Science and Technology
• /
• v.1 no.2
• /
• pp.121-126
• /
• 2010

An amperometric ascorbic acid selective sensor utilizing the transfer reaction of proton liberated from the dissociation of ascorbic acid in aqueous solution across an elliptic micro-hole water/organic gel interface is demonstrated. This redox inactive sensing platform offers an alternative way for the detection of ascorbic acid to avoid a fouling effect which is one of the major concerns in redox based sensing systems. The detection principle is simply measuring the current change with respect to the assisted transfer of protons by a proton selective ionophore (e.g., ETH 1778) across the micro-hole interface between the water and the polyvinylchloride-2-nitrophenyloctylether gel phase. The assisted transfer reaction of protons generated from ascorbic acid across the polarized micro-hole interface was first characterized using cyclic voltammetry. An improved sensitivity for the quantitative analysis of ascorbic acid was achieved using differential pulse stripping voltammetry with a linear response ranging from 1 to $100\;{\mu}M$ concentrations of ascorbic acid. As a demonstration, the developed sensor was applied for analyzing the content of vitamin-C in different types of commercial pharmaceutical tablets and syrups, and a satisfactory recovery from these samples were also obtained.

• Computers and Concrete
• /
• v.5 no.2
• /
• pp.101-116
• /
• 2008

The microscopic determination of air void characteristics in hardened concrete, defined in EN 480-11 as the linear-traverse method, is an extremely time-consuming and tedious task. Over past decades, several researchers have proposed relatively expensive mechanical automated systems which could replace the human operator in this procedure. Recently, the appearance of new high-resolution flatbed scanners has made it possible for the procedure to be automated in a fully-computerized and thus cost-effective way. The results of our work indicate the high sensitivity of such image analysis automated systems firstly to the quality of sample surface preparation, secondly to the selection of the air void threshold value, and finally to the selection of the probe system. However, it can be concluded that in case of careful validation and the use of the approach which is proposed in the paper, such automated systems can give very good estimate of the air void system parameters, defined in EN 480-11. The amount of time saved by using such a procedure is immense, and there is also the possibility of using alternative stereological methods to assess other, perhaps also important, characteristics of air void system in hardened concrete.

• Journal of Arbitration Studies
• /
• v.23 no.1
• /
• pp.85-105
• /
• 2013

The entertainment industry has developed along with current Korean wave fever, and so entertainment-related disputes are increasing rapidly. Litigation is a poor fit for entertainment disputes because of characteristics such as temporal sensitivity. Thus, in the US, the entertainment industry resolves these disputes through ADR mechanisms like arbitration, but cases of settling such disputes through arbitrations are very rare in Korea. This study examined the characteristics and types of entertainment disputes and considered the compatibility of arbitration as a method for settling disputes, and then suggested tasks for revitalizing arbitration systems as entertainment dispute resolution procedures. Arbitrations have many merits, such as the rapid pace of procedures, confidentiality, satisfying the long-term desires of business relationships, the low cost of settling disputes, judgments rendered by experts, etc.; thus, it is a very suitable mechanism to settle entertainment-related disputes. The study proposes necessary steps for revitalizing arbitration systems for entertainment disputes. First, awareness of entertainment industry workers about the arbitration system should be raised. Second, special educational programs for members the of Korean Commercial Arbitration Board related to entertainment should be set up and operated together with encouraging positive attitudes toward actions like establishing a dedicated arbitration unit on entertainment disputes. Third, neutral, professional arbitrators should be secured and aggressive disclosures made. Fourth, a professional ADR organization such as an "Entertainment Arbitration Committee" should be established.

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.5 no.1
• /
• pp.33-46
• /
• 2013

A computational fluid dynamics (CFD) code, dubbed SNUFOAM, was developed to predict the performance of ship resistance using a CFD tool kit with open source libraries. SNUFOAM is based on a pressure-based cell-centered finite volume method and includes a turbulence model with wall functions. The mesh sensitivity, such as the skewness and aspect ratio, was evaluated for the convergence. Two wall functions were tested to solve the turbulent flow around a ship, and the one without the assumption of the equilibrium state between turbulent production and dissipation in the log law layer was selected. The turbulent flow around a ship simulated using SNUFOAM was compared to that by a commercial CFD code, FLUENT. SNUFOAM showed the nearly same results as FLUENT and proved to be an alternative to commercial CFD codes for the prediction of ship resistance performance.

• Advances in Energy Research
• /
• v.1 no.2
• /
• pp.127-146
• /
• 2013

Torrefaction technologies convert assorted biomass feedstocks into energy-concentrated, carbon neutral fuel that is economically transported and easily ground for blending with fossil coals at numerous power plants around the world without needs to retrofit. Utilization of torrefied biomass in conventional electric generating units may be an increasingly attractive alternative for electricity generation as aging power plants in the world need to be upgraded or improved. This paper examines the economic feasibility of torrefaction in different scenarios by modeling torrefaction plants producing 136,078 t/year (150,000 ton/year) biocoal from wood and corn stover. The utilization of biocoal blends in existing coal-fired power plants is modeled to determine the demand for this fuel in the context of emerging policies regulating emissions from coal in the U.S. setting. Opportunities to co-locate torrefaction facilities adjacent to corn ethanol plants and coal-fired power plants are explored as means to improve economics for collaborating businesses. Life cycle analysis was conducted in parallel to this economic study and was used to determine environmental impacts of converting biomass to biocoal for blending in coal-fired power plants as well as the use of substantial flows of off-gasses produced in the torrefaction process. Sensitivity analysis of the financial rates of return of the different businesses has been performed to measure impacts of different factors, whether input prices, output prices, or policy measures that render costs or rewards for the businesses.

• IE interfaces
• /
• v.13 no.4
• /
• pp.658-667
• /
• 2000

Seasonal variation of natural gas demand coupled with rigid and stable import pattern of gas represents the characteristic feature of the Korean Liquified Natural Gas(LNG) industry. This attribute has required a huge amount of investment for the construction of storage facility. Thus, to minimize the supply cost, it is legitimate to reduce storage requirement itself. In this study, we combine three alternative methods to deal with the storage requirement to minimize the supply cost. Those are (1) adding additional storage tanks, (2) inducing large firm customers, and (3) constructing gas-turbine self generation facilities. Methodologically, we employ the mixed integer program (MIP) to optimize the system. The model also consider demand and price-setting scheme in separate modules. From the results, it is shown that if alternatives are combined optimally, a number of storage tanks can be reduced substantially compared with the original capacity plan set by the industry authorities. We perform various sensitivity analyses to check the robustness of the results. The methodology presented in this study can be applied to the other physical network industry, such as hydraulics. The empirical results will shed some light on the rationalization of capacity planning of the Korean natural gas industry.

• Journal of Korean Port Research
• /
• v.7 no.1
• /
• pp.5-12
• /
• 1993

In complex decision making such as ill-defined system, one of the main problem is how to treat ambiguous aspect of the decision making. According to the complexity and ambiguity of the objective systems, many types of evaluation attributes are necessary for the rational decision and the relationship among the attributes become complex and fuzzy. Fuzzy integral is very effective to evalute the complex system with interaction between attributes but how to save the evaluation efforts in the decision making process of grading the membership of the objects or alternative is the problem to be tackled. Because the more object there are to evaluate, the number of decisions to made increase exponentially. Therefore, this paper aimes to propose a new evaluation algorithm based on fuzzy integral which can save the evaluator's efforts in decision making process. The proposed algorithm is constructed as follows : First, compose the fuzzy measure by introducing AHP(Analytical Hierachy Process) & mutual interaction coefficient. Second, generate fuzzy measure value of monotone family set for calculating the fuzzy integral. The effectiveness of the proposed algorithm is investigated through the example and sensitivity of interaction coefficient is illustrated.

• Journal of Korean Academy of Fundamentals of Nursing
• /
• v.4 no.2
• /
• pp.351-358
• /
• 1997

Body temperature should be measured accurately to assess neonate's condition for proper care. Temperatures measured in rectal, axillary and tympanic site were compared in 129 normal neonates to find out proper nursing time for measuring temperature and the validity of fever detection. The results were as follows : 1. Mean temperatures of axillary and tympanic site($36.85^{\circ}C,\;37.12^{\circ}C$) were significantly lower than those of rectal site($37.19^{\circ}C$). 2. Mean nursing time for measuring body temperature was significantly higher and lower in axillary and tympanic temperatures(159.49 seconds, 11.07 seconds) than in rectal temperature(105.62 seconds). 3. Tympanic and axillary temperatures were significantly correlated with rectal temperature (r=0.85, r=0.78) and the significant correlation was demonstrated between tympanic and axillary temperatures(r=0.76). 4. Sensitivity, specificity, positive and negative predictive values were 0.87, 0.90, 0.72, 0.96 for detecting fever respectively. The above findings indicated that the tympanic thermometer offers a useful alternative to conventional methods.

• Journal of the Korean Society for Railway
• /
• v.11 no.6
• /
• pp.530-535
• /
• 2008

After train fire accident in Daegue, many research on train fire safety improvement have been carrying out. Since many alternative fire safety measures can be applied in our railway system, the effect of the each safety measure must be quantified prior to the safety investment. In order to estimate the effects of each safety measure quantitatively, fault trees and event trees are constructed in this study. Results can be applied for cost-benefit analysis or sensitivity analysis for safety measures in risk assessment process.

• Nuclear Engineering and Technology
• /
• v.49 no.5
• /
• pp.979-988
• /
• 2017

The feasibility of cooling in a pressurized heavy water reactor after a large break loss-of-coolant accident has been analyzed using Multidimensional Analysis of Reactor Safety-KINS Standard code during the recirculation phase. Through evaluation of sensitivity of the fuel channel temperature to various effective recirculation flow areas, it is determined that proper cooling of the fuel channels in the broken loop is feasible if the effective flow area remains above approximately 70% of the nominal flow area. When the flow area is reduced by more than approximately 25% of the nominal value, however, incipience of boiling is expected, after which the thermal integrity of the fuel channel can be threatened. In addition, if a dramatic reduction of the recirculation flow occurs, excursions and frequent fluctuations of temperature in the fuel channels are likely to be unavoidable, and thus damage to the fuel channels would be anticipated. To resolve this, emergency coolant supply through the newly installed external injection path can be used as one alternative means of cooling, enabling fuel channel integrity to be maintained and permanently preventing severe accident conditions. Thus, the external injection flow required to guarantee fuel channel coolability has been estimated.