• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.6
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• pp.474-481
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• 2011

The discharge coefficient and spatial velocity distribution were clarified by carrying out a physical experiment to assess the performance of sluice for tidal power generation. The physical experiment was performed by manufacturing 10 sluce models whose scale is 1/70 of the prototype and installing it in the planar open channel, which has apron sections in front of and behind the sluice models. In particular, it was attempted to reasonably determine the locations and method of measuring water levels that may affect estimation of the discharge coefficient. Based on the experimental results for various conditions of discharges and tidal levels, the discharge coefficient of the sluice in the experiment was estimated as 1.3 to 1.4. Meanwhile, it was found that velocities were 2~3% faster at the sluices near the central region whereas 4~5% slower at the sluices on both sides, in comparison to the average value of the mean velocities of the ten sluices.

• Clean Technology
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• v.5 no.1
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• pp.78-85
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• 1999

In the Kimchi manufacturing industry that has recently been on its greatest growth, the rinsing process for salt-pickled Chinese cabbage in a brining step generates a vast amount of rinsing wastewater containing salts, colloids, and organics released from the raw material. In this study, the experimental method was developed to optimize the rinsing water consumption and thus to minimize the rinsing wastewater generation. The continuous counter-current rinsing basin in the actual plant was simulated through the lab-scale three batch-wise rinsing tanks. Rinsing efficiencies for the brined cabbage from the same brining tank were almost in the same level, whereas those varied substantially from source to source in the raw Chinese cabbage provided. When rinsing water used were decreased from 3.3 L/head to 2.7 L/head, no significant change was observed with respect to COD, turbidity, conductivity, $Na^+$, and $Cl^-$ concentrations in the extracted solution of the rinsed cabbage. However, the quality of the extracted solution was badly deteriorated as the amount of rinsing water used dropped down to below 2.7 L/head. The reduction of rinsing water up to 18% was proved to be possible without any negative effect on the quality of the product, Kimchi.

• Korean Chemical Engineering Research
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• v.44 no.2
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• pp.149-159
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• 2006

This research is a development of useful S/W program for real industry about optimal product scheduling in real plant for manufacturing polymer products. For this, we used a fine model with total amount of losses in weight(ton) as an objective for optimal scheduling and a genetic algorithm for optimization in this factory they manufacture three different products. Major products are A and B but the product which can be process in the period of products change over. They also sells them as a chap product in market. The major products have several types of packing process-bulk, pack for domestic market, pack for export. The demands of product with each packing type are increased, and frequently they failed keep the deadline for sail. Based on realistic production situation, we composed a fine modeling for optimal scheduling. And we also develop a S/W program for optimal scheduling which can be used by non-specialist in scheduling problem. We used a modified genetic algorithm and it gave us a better solution in process. We can have a result of reducing the total amount of losses in weight by half compared with the losses when existing production schedule.

• Composites Research
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• v.29 no.1
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• pp.40-44
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• 2016

Nuclear fuel cladding used in a nuclear power plant must possess superior oxidation resistance in the coolant atmosphere of high temperature/high pressure. However, as was the case for the critical LOCA (loss-of-coolant accident) accident that took place in the Fukushima disaster, there is a risk of hydrogen explosion when the nuclear fuel cladding and steam reacts dramatically to cause a rapid high-temperature oxidation accompanied by generation of a huge amount of hydrogen. Hence, an active search is ongoing for an alternative material to be used for manufacturing of nuclear fuel cladding. Studies are currently aimed at improving the safety of this cladding. In particular, ceramic-based nuclear fuel cladding, such as SiC, is receiving much attention due to the excellent radiation resistance, high strength, chemical durability against oxidation and corrosion, and excellent thermal conduction of ceramics. In the present study, cladding with $SiC_f/SiC$ protective films was fabricated using a process that forms a matrix phase by polymer impregnation of polycarbosilane (PCS) after filament-winding the SiC fiber onto an existing Zry-4 cladding tube. It is analyzed the oxidation and microstructure of the metal cladding with $SiC_f/SiC$ composite protective films using a drop tube furnace for thermal shock test.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.11
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• pp.855-859
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• 2011

The main pollutants from zirconium alloy tubing manufacturing process in nuclear industry are nitrate ($NO_3-N$) and fluoride (F-)Nitric acid, and hydrofluoric acid is used for acid pickling. The process for the removal of nitrate and fluoride is composed of 1st chemical coagulation, SOD (Sulfur Oxidation Denitrification) process using sulfur-oxidizing denitrification, and 2nd chemical coagulation. The characteristic of the wastewater treatment is an application of SOD process. The SOD Process is highly received attention because it is significantly different from existing processes for sulfur denitrification. A JSC (JeonTech-Sulfur- Calcium) Pellet is unification of sulfur and alkalinity material. According to result of SOD process in wastewater treatment plant, the removal efficiency of T-N was over 91% and the average concentration of T-N from influent was 147.55 mg T-N/L and that from effluent was 12.72 mg T-N/L. Therefore, SOD process is a useful to remove nitrogen from inorganic industrial wastewater and a new development of microbial activator was shown to be stable for activation of autotrophic bacteria.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.8 no.2
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• pp.91-97
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• 2010

As nuclear power plants are getting older, interests on a decontaminating process are increasingly attracting more attention. Chemical decontamination is crucial to lower the production of radioactive waste and radiation dose rate. Prior to this, oxidizers and detergents for target material should be chosen so as to decontaminate major systems and components of a nuclear power plant chemically. In order to decontaminate it properly, it is crucial to have information about the chemical composition and crystalline structure of CRUD, analyzing its samples from the target or the decontamination system with components. However, there is no program which enables the extraction of samples directly from the object or the decontamination system with components carrying genuine radioactivity. Therefore, it is limited to samples from corrosion products carrying partial radioactivity as a resource. The composition of CRUD varies considerably depending on refueling cycle because it is closely related to the constituent of basic material. After settling a target, it is crucial to analyze and obtain analytical information about CRUD as a decontamination target. In this paper, various technologies for manufacturing simulated CRUD are introduced as alternatives to unattained samples. A metal oxide or metal hydroxide was used to synthesize simulated cruds having chemical compositions and crystalline stricture similar to the actual one by 12 different methods. CRUD 4(metal oxides in the autoclave vessel) and CRUD 10(metal oxides in a crucible after hydrazing pretreatment)were chosen as the best method for Type 1 and Type 2.respectively. As these CRUD can be synthesized easily without using any specialized equipment or reagents in a short time and in large quantities, they are expected to stimulate the development of decontaminating agents and processes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.1
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• pp.70-80
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• 2020

This study examined the effects of the R&D project managers' leadership on the product development performance. A survey was carried out empirically on a group of 175 experts associated with project management R&D operations in the field of manufacturing, construction engineering, shipbuilding, plant, and IT. The survey results showed that the effects of the R&D project managers' leadership on the product development performance were not significant, and the mediating effects of the project sponsor roles were significant. This means that the leadership of leaders, which requires efficient control and management based on complicated intergroup relationships and roles, is important in a project involving experts from the professional field. This suggests that the efficient leadership of leaders can improve the performance through the cooperation of members in the organization and aggregation of their core competencies in a limited time. Overall, the key results of this study mean that project leaders should play an active mediating role to maximize their leadership and enhance the role of project sponsors. In addition, the mediating role of project sponsors has an effect on the leadership of project managers, affecting the project performance quality.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.5
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• pp.623-629
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• 2018

Smart Factory is a concept of automatic production system of machines by the fusion of ICT and manufacturing. As a base technology for realizing such a smart factory, there is an increasing interest in a low-power environmentally friendly LED lighting system, and researches on so-called optical ID related application technologies such as communication using a LED and position recognition are actively underway. In this paper, We have proposed a system that can reliably identify logistics location and additional information without being affected by electromagnetic interference such as high voltage, high current, and generator in the plant. Through the basic experiment, we confirmed the applicability of the color ID recognition rate from 98.8% to 93.8% according to the eight color variations in the short distance.

• International Journal of Highway Engineering
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• v.11 no.4
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• pp.133-142
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• 2009

This research is performed to estimate quality of trial pavement for construction and analyze effect of fatigue life by using the pay factor. Specially, asphalt content which is difficult to control the pavement quality, is selected by pay adjustment standard factors and pay factor is calculated by asphalt content. This research is also analyzed to present relation of fatigue life according to asphalt content, to evaluate quality of the road pavement by calculating pay factor of sampling trial field mixture 2 times. This research confirms that it is different quality of road pavement according to pay factor changes. To analyze the fatigue life of pavement by using asphalt mixture for trial field. As a result, it is conformed that high pay factor could be high fatigue life of trial field. This means that pay factor using probability theory reflects road pavement fatigue life. Also, this study is included that beam fatigue test manufacturing specimen such as mixing type of plant which purvey asphalt mixture to trial field, compared with fatigue life of trial field. As a result, the fatigue life of specimen that is manufactured by mix type is higher than trial field specimen. This means that performance of road pavement can be reduced by gradation or other effects. Therefore, to exactly evaluate the quality of road pavement, pay factor should be calculated appling various pay adjustment standard factors such as gradation, air-void in U.S. states which is adopted pay adjustment.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.27 no.1
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• pp.38-45
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• 2017

Objectives: Radon may be second only to smoking as a cause of lung cancer. Radon is a colorless, tasteless radioactive gas that is formed via the radioactive decay of radium. Therefore, radon levels can build up based on the amount of radium contained in construction materials such as phospho-gypsum board or when ventilation rates are low. This study provides our findings from evaluation of radon gas at facilities and offices in an industrial complex. Methods: We evaluated the office rooms and processes of 12 manufacturing factories from May 14, 2014 to September 23, 2014. Short-term data were measured by using real-time monitoring detectors(Model 1030, Sun Nuclear Co., USA) indoors in the office buildings. The radon measurements were recorded at 30-minute intervals over approximately 48 hours. The limit of detection of this instrument is $3.7Bq/m^3$. Also, long-term data were measured by using ${\alpha}-track$ radon detectors(${\alpha}-track$, Rn-tech Co., Korea) in the office and factory buildings. Our detectors were exposed for over 90 days, resulting in a minimum detectable concentration of $7.4Bq/m^3$. Detectors were placed 150-220 cm above the floor. Results: Radon concentrations averaged $20.6{\pm}17.0Bq/m^3$($3.7-115.8Bq/m^3$) in the overall area. The monthly mean concentration of radon by building materials were in the order of gypsum>concrete>cement. Radon concentrations were measured using ${\alpha}-track$ in parallel with direct-reading radon detectors and the two metric methods for radon monitoring were compared. A t-test for the two sampling methods showed that there is no difference between the average radon concentrations(p<0.05). Most of the office buildings did not have central air-conditioning, but several rooms had window- or ceiling-mounted units. Employees could also open windows. The first, second and third floors were used mainly for office work. Conclusions: Radon levels measured during this assessment in the office rooms of buildings and processes in factories were well below the ICRP reference level of $1,000Bq/m^3$ for workplaces and also below the lower USEPA residential guideline of $148Bq/m^3$. The range of indoor annual effective dose due to radon exposure for workers working in the office and factory buildings was 0.01 to 1.45 mSv/yr. Construction materials such as phospho-gypsum board, concrete and cement were the main emission sources for workers' exposure.