• Korean Journal of Construction Engineering and Management
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• v.11 no.3
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• pp.134-144
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• 2010

In China, the enhancement of water services has become the most crucial issue confronted with the rapid urbanization and industrialization process. A huge financial gap to meet the demand for water infrastructure and need for adopting advanced operation technology precipitated the rapid growth of PPP over the last 10 years. Diverse schemes of PPP such as TOT, Divestiture, and Management Contract and Lease have been practiced. Local governments and private investors/operator have adjusted their objectives and strategies to avoid potential pitfalls behind BOT projects in China. However, current academic research outcomes do not properly reflect important issues of BOT projects or related case studies in China. This limitation has brought in the lack of assessment of important risks and success factors required for the improvement of the body of risk management. In this regard, this study uses the market analysis method to identify major schemes of PPP water projects and conducts case studies on five PPP projects to identify key risk and success factors in association with each different scheme. It is expected that the risk and success factors identified from the cases will be used as reference to Korean companies which plan to enter the Chinese water market.

• Korean Chemical Engineering Research
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• v.55 no.4
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• pp.567-573
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• 2017

In this work, tungsten oxide ($WO_x$) supported on SBA-15 (mesoporous silica) were prepared and applied for oxidative desulfurization of sulfur compounds in marine diesel containing about 230 ppmw of sulfur concentration. Prepared catalysts were examined by two steps; at first step, oxidation reaction carried out with hydrogen peroxide as oxidant and then the oxidized sulfur compounds were extracted by acetonitrile as solvent. Catalysts were characterized by using X-ray diffraction, X-ray fluorescence, X-ray photoelectron spectroscopy and $N_2$ adsorption-desorption isotherms. Tungsten oxide exists as monoclinic crystal system on SBA-15 and over about 10 wt% of the $WO_x$ loading took the form of multi-layers on SBA-15. The 13 wt% $WO_x$/SBA-15 catalyst exhibite highest activity, achieving about 76.3% sulfur removal in the reaction conditions, such as catalyst amount of 0.1 g, reaction temperature at $90^{\circ}C$, reaction time for 3 h and O/S molar ratio of 10. One time oxidation reaction is enough oxidize the sulfur compounds in marine diesel completely. The repetition experiment of extraction process indicated that sulfur removal could reach 94.4% after 5 times.

• KSBB Journal
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• v.20 no.6
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• pp.431-437
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• 2005

Molecular methods were employed to investigate microorganisms in a thermophilic continuous stirred tank reactor(CSTR) used for continuous $H_2$ production. The reactor was inoculated with heat-treated anaerobic sludge and fed with a glucose-based medium. Denaturing gradient gel electrophoresis showed dynamic changes of bacterial populations in the reactor during 43 days of operation. Gas composition was constant from approximately 14 days but population shift still occurred. Populations affiliated with Fervidobactrium gondwanens and Thermoanaerobacterium thermosaccharolyticum were dominant on 21 and 41 days, respectively. Keeping pH of the medium at 5.0 could suppress methanogenic activity that was detected during initial operation period. $CH_4$ and mcrA detected in the samples obtained from the reactor or inoculum suggested the heat treatment condition employed in this study is not enough to remove methanogens in the inoculum. PCR using primer sets specific to 4 main orders of methanogens suggested that major $H_2$-consuming methanogens in the CSTR belong to the order Methanobacteriales.

• KSBB Journal
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• v.20 no.6
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• pp.425-430
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• 2005

Thermophilic $H_2$ was produced for 1 year using a bench-scale continuous stirred tank reactor(CSTR). The CSTR was inoculated with anaerobically digested sludge after heat treatment and fed with a glucose-based medium. The reactor showed relatively short start-up period(30 days) and high maximal $H_2$ yield(2.4 mol $H_2/mol$ glucose). Keeping pH 5.0 or less suppressed methanogenic activity. Bacteria affiliated with Thermoanaerobacterium thermosaccharolyticum kept being dominant from approximately 40 days as determined by DGGE. Environmental perturbation(pH or temperature) caused the decrease of biomass concentration in the reactor and the instability of reactor performance, $H_2$ production rate and $H_2$ yield. The unstable performance was accompanied with high concentration of lactate in the effluent. Taken together, the poor recovery of CSTR after perturbations could be partly explained by low biomass concentration and/or metabolic shift of the major population in the CSTR.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.6
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• pp.2596-2603
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• 2013

The precision and endurance of tire mold are very important factors to decide the quality of tire. However, the investigation on the thermal deformation of tire mold has a lot of trouble because the tire mold is produced in airtight permanent casting material. In this study, the thermal deformations such as temperature, displacement and stress distributions inside the AC7A tire mold casting material were analyzed by numerical analysis according to the preheating temperature of permanent casting device. In order to verify the results of numerical analysis, the experiments for temperature measurement of the AC7A casting material were carried out under the same condition with numerical analysis. For the numerical analysis, "COMSOL Multiphysics" was used. The preheating temperatures were set up $150^{\circ}C$, $200^{\circ}C$, $250^{\circ}C$ and $300^{\circ}C$, respectively. The thermal deformations were calculated in each case. When the preheating temperature is $300^{\circ}C$, displacement and stress are the lowest with 0.25mm and 0.351GPa, but the temperature is the highest with $374.27^{\circ}C$. When the experimental results were compared with the numerical results, there were some temperature differences because of the latent heat by phase change heat transfer. However, the cooling patterns were almost similar except for the latent heat section.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.12
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• pp.768-777
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• 2017

The efforts to improve river levee maintenance technologies have accelerated globally in a bid to deal with the flood damage resulting from the changes to the climate and flood events. This paper, in line with such tendency, proposes an evaluation system of a river levee safety map to maintain the river levee in an efficient manner. The concept of a river levee safety map is aimed at maximizing the maintenance efficiency for a manager to indicate the safety index, including the current river levee sliding, piping, and visual inspection on a GIS map. To develop such an evaluation system, a safety index covering the sliding, piping, and visual inspection are designated through the data and document examination and the rational guideline to classify each index into three grades, A, B, and C, is proposed. Based on the guideline proposed, the sliding and piping characteristics in terms of safety depending on the change to the flood water level duration time at the test section (Nam river) were evaluated by numerical analysis. As a result, both the protected landside and riverside satisfied the requirements for Grade A in terms of sliding, and when it comes to piping, the grade declined to C because the flood water level duration time increased at R2. As a planning study to propose a river levee safety map evaluation system, a further advanced study, standardization of the river levee data, and improvement of the existing system and laws are required.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.9
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• pp.261-268
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• 2018

The use of electric cable was limited due to the installation time and large space as the increase of power demand and load quantity in side line. In order to solve these problems, the application of busway system which can supply the large current was increasing. But it was lack of methods of performance tests to evaluate the reliability and results of test for busway system. In this paper, we presented items to evaluate the reliability test for epoxy coated busway system with reference to IEC 61349-6. In addition, we proposed items to evaluate the reliability and long term life cycle test for the epoxy coated busway system. The combined acceleration deterioration test that reflects actual conditions of the survey as much as possible was conducted considering both thermal and electrical stresses. The deterioration condition was selected to satisfy fifty years life expectation and the insulation performance verification test of the busway system confirmed the long term life prediction. Furthermore, as test items for reliability assessment of compliance with the environment for the use of temperature, humidity and load current where busway system was installed, thermal overload test, water immersion test, cold shock temperature test and thermal cycle test were performed. And we examined changes in characteristics and abnormality after tests. From results, the test items presented to evaluate performance and reliability of the epoxy insulated busway system were confirmed to be appropriate in this paper, and the performance of the product was also confirmed to be excellent for reliability tests.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.9
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• pp.1459-1463
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• 2005

Not enough data on nutritional change of foods by gamma irradiation are accumulated. It is known that amounts and digestibility of macronutrients such as carbohydrates, proteins and lipids are not significantly altered by irradiation treatment. However, among micronutrients, vitamins are known to be susceptible to irradiation. This study was conducted to investigate the change of contents of riboflavin in egg powder and niacin in chicken breast. By irradiation of 5 and 10 kGy, riboflavin contents of egg powder were respectively reduced to $80.18\%\;and\;84.80\%$ of non-irradiated sample, and niacin contents in chicken breast were reduced to $85.30\%\;and\;92.60\%$, respectively. These results suggest that the reduction rate by gamma irradiation seems to be lower in niacin content than in riboflavin, and the losses of riboflavin and niacin occur within the range of $20\%$ by irradiation of up to 10 kGy.

• Journal of Distribution Research
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• v.15 no.5
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• pp.61-79
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• 2010

As the interest and the importance of environmental protection increases rapidly, the environment considers to be not only the item that requires a control and a duty fundamental element but the fundamental element to enhance the internection icompetitiveness n so. Along with the collapse of the foreign trade barrier and the quality improvement of a customer's life qu life of a an object is shortened liforder to sectsfy the customer's lemands and as the result of it quaother critical issues rmparding the waste treatment and recasles are now thought to be momentou onlyaddition to the issue of the greenhou e gases reduction that is considered as one of me q issues among many internection ienvironmental issues. To keep up the pace with the environmental flow qube notd countries have nlreal iput their attempts to solve this environmental problems through a number of rmpulactios and acctios and they have showed a great concern for it as it is an internection iproblem that they should aasroaeronlythe aspect of not just a compan isr a country but of the wte e globn ivillage. Sueroenvironmental flow alemaned the logistic stratmpy of a compan iand it brought up the demand for the reverse logistics in a supply chain. For the reason above, the concept of reverse logistics and classification, the comparison with any similar concepts and its necessity are studied in this research through the theoretical consideration and the current state of the reverse logistics is organized in this research by acknowledging the domestic development process and the properties regarding the recycles of resources. In addition, the way to apply to the nation was investigated by comparing with the environmentalism development process, the reverse logistics policies and examples of advanced countries in logistics. The research proposed building of intimate cooperative system between a shipper and logistic service provider for the reverse logistics throughout the whole supply chain, the financial support, amendment of regulations, support Eco-friendly logistic technology development and the propagation, effective logistic system development and others and it is expected to bring a significant meaning to the reverse logistic policy and operation later on.

• Journal of the Korea Concrete Institute
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• v.21 no.5
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• pp.573-580
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• 2009

This paper presents the mix composition, production method, and curing condition applied to the extruded ECC(Engineered Cementitious Composite) panel which are able to exhibit multiple cracking and potential pseudo strain-hardening behavior. In addition to the production technique of extruded ECC panel, the effect of fiber distribution characteristics, which are uniquely created by applying extrusion process, on the flexural behavior of the panel is also focussed. In order to demonstrate fiber distribution, a series of experiments and analyses, including image processing/analysis and micro-mechanical analysis, was performed. The optimum mix composition of extruded ECC panel was determined in terms of water matrix ratio, the amount of cement, ECC powder, and silica powder. It was found that flexural behavior of extruded ECC panel was highly affected by the slight difference in mix composition of ECC panel. This is mainly because the difference in mix composition results in the change of micro-mechanical properties as well as fiber distribution characteristics, represented by fiber dispersion and orientation. In terms of the average fiber orientation, the fiber distribution was found to be similar to the assumption of two dimensional random distribution, irrespective of mix composition. In contrast, the probability density function for fiber orientation was measured to be quite different depending on the mix composition.