• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.207-208
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• 2022

Since 1960, the green area has decreased due to rapid urbanization and the artificial surface has increased, and the repair and water function of the previous surface has decreased due to the decrease in rainwater absorption capacity. In addition, the risk of carbon dioxide and fine dust is emerging due to the use of fossil fuels due to urbanization. As a result, permeable blocks, an eco-friendly product, are in the spotlight. Therefore, this study was conducted to examine the strength properties of the permeable block using a hydroball. As a result of the experiment, the flexural strength and compressive strength tended to decrease as the hydroball replacement rate increased. It is judged that the hydroball absorbs a large amount of moisture during the mixing process and lacks moisture required for curing, resulting in a decrease in strength. According to KS F 4419, since the hydroball replacement rate is satisfied up to 20%, further research is needed to analyze the adsorption performance of air pollutants in the future and evaluate their utilization as a permeable block in the future.

• Applied Biological Chemistry
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• v.27
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• pp.68-79
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• 1984

An increased population and rapidly expanding industrial development have led to enormous amounts of various domestic and industrial wastes. The proper disposal of ever-increasing wastes is a growing global problem. Land treatment is one of the rational approaches that are environmentally safe and economically practical. It has long been practised in many sites. Recycling of industrial wastes on agricultural land can provide better possible means for maintaining environmental quality and utilizing waste-resources. Even though industrial wastes are beneficial as soil amendment and fertilizer, they have some limitation on land application because of wide variability as well as physicochemical problem in their composition. A direct application of solid and liquid wastes on land is being practised in Korea and some experimental results are presented. The direct application of fermentation waste on rice resulted in a 6 percent yield increase. Another organic residue from glutamic acid fermentation is widely used not only as a direct application as a liquid fertilizer but also for a raw material of organic compound fertilizer. These wastes are much promising as sources of plant nutrients, since they have large amounts of nutrients, especially nitrogen with few toxic metals. On the other hand, fertilizers developed from inorganic industrial wastes include calcium silicate, calcium sulfate and ammonium sulfate. The calcium silicate fertilizer simply produced from slag, by-product of iron and steel manufacturing plant is one of the most successful example of the conversion of wastes to fertilizer and slag production capacity totals to over three million MT/year. About 200,000 MT of calcium silicate fertilizer is currently applied in the paddy rice every year. Calcium sulfate, a waste from the wet phosphoric acid process is to some extent used as a filler of compound fertilizers but quite large quantites are directly applied for the reclamation of tidal flat.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.3
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• pp.206-212
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• 2017

Induction motor torque is the reactive power is needed which corresponds to the exciting current to generate the magnetic flux as the product of current and flux. For use in the method of supplying the required reactive power to the induction motor power factor correction apparatus using a lot of ways to supply in place of the power supply side, when using a power factor compensation device can reduce the apparent power, the power factor can be improved. However, the distance to the emergency generator transformers or motors from the motor capacity is smaller but short and difficult to maneuver the theory and practice of the operating characteristics of the starting characteristics of the motor used a lot of large industrial plants were measured and analyzed. Therefore, this study investigated the motor starting Analysis and interpretation for the relationship with the large motor starting torque and speed during motor starting.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.3
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• pp.1658-1663
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• 2015

To control the indoor humidity, humidifier is installed in an air handling unit. Up to now, foreign product made of glasswool has been widely used as a humidifying element. In this study, a new humidifying element made of cellulose and PET was tested, and the performance was compared with Glasdek element, which is made of glasswool. Mass transfer rates and pressure drops were measured from the element which was installed at the entrance of the suction-type wind tunnel. Results show that, $j_m$ and f factors of the new element are 33%~39% larger and 0%~51% smaller than those of Glasdek. Large water absorption capacity and the smoothness of the new element appear to be responsible for the large $j_m$ and small f factor. The mass transfer effectivenesses ($j_m/f^{1/3}$) of the new element are 36%~63% larger than those of Glasdek.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.3.1-3.1
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• 2009

Normal sintering process of producing porous ceramics is not to sinter perfectly, i.e., stop sintering in middle-process. Our porous ceramic materials are a product of complete sintering. For example if one want to make a porous carborundum, raw carborundum powder is sintered at either lower temperatures than normal sintering temperature or shorter sintering periods than normal sintering time to obtain incompletely sintered materials, i.e., porous carborundum. This implies normally sintered porous ceramic materials can mot be used in high vacuum conditions due to dust coming out from uncompleted sintering. We could produce completely sintered porous ceramic materials. For example, we can produce porous carborundum material by using carborundum particles bonded by glassy material. The properties of this material are similar to carborundum. We could make quasi-zero thermal expansion porous material by using carborundum and particles of negative thermal expansion materials bonded by the glassy material. We apply to sinter them also by microwave to sinter quickly. We also use HIP process to introduce closed pores. We could sinter them in large size to produce $2.5m{\times}2.5m$ ceramic plate to use as a precision plate for flat display industries. This flat ceramic plate is the world largest artificial ceramic plate. Precision plates are basic importance to any advanced electronic industries. The produced precision plate has lower density, lower thermal expansivity, higher or similar damping properties added extra properties such as vacuum vise, air sliding capacity. These plates are highly recommended to use in flat display industries. We could produce also cylindrical porous ceramics materials, which can applied to precision roller for polymer film precision motion for also electronic industries.

• Resources Recycling
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• v.22 no.4
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• pp.70-80
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• 2013

Waste refrigerator is the most large amount of item being recycled and the recycling process is the most complicated in WEEE (Waste Electrical and Electronic Equipment) because refrigerator is biggest product and consists of various parts and materials such as ferrous, non-ferrous, and plastics. Recently, recycling process of waste refrigerator has been being more complex since large capacity 2 door refrigerators and standing Kimchi refrigerators with various material are distributed on custom market. In addition, recycling of valuable resource from waste refrigerator is mandatory by WEEEs recycling legislation; therefore, high efficiency recycling enough for economic and environment-friendly recovery of valuable resource through present technical situation analysis and comparison of recycling technologies of waste refrigerator with advanced country.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.14 no.5
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• pp.25-42
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• 2019

The purpose of this study is to analyze the effect of internal competence of small business on the competitive advantage and start-up intention. Through this, which key competence of small business can be proposed for market growth against of large companies that have a great capital power. Also, implications for development direction can be suggested. For this purpose, technology capability, financing capability, marketing capability, and product/service differentiation capability factors were set as independent variables, as well as competitive advantage as a mediating factor, and startup intention to be franchiser as a dependent variable. For the analysis, a structured questionnaires survey was conducted to 276 domestic small business in capital area. The main results are as follows. First, in relation to the internal competency and the competitive advantage of small businesses, it was found that technological capabilities, financing capabilities and product (service) differentiation have a positive effect on competitive advantage. Second, the relationship between the internal capacity of a small entity and startup intention to commercialize a franchiser business indicates that its financing capacity and marketing capabilities have a positive effect on startup intention to commercialize the business, and that competitive advantage has a significant effect on startup intention to commercialize the franchise. Third, competitive advantage was found to mediate the relationship between internal competency and startup intention. Finally, it was shown that the internal capacity of a small business has a regulating effect in relation to its financing capacity, marketing capabilities and startup intention to commercialize the franchise, and that it also had a regulating effect in relation to its relationship with its competitive advantage and franchise suitability. Based on the above results, if small business can take competitive advantage in the market, they also consider startup intention to commercialize a franchiser, in addition, it is expected that one suggestion can be made from an internal capacity perspective required more emphasis on operations and management as an alternative to expanding small businesses' business, including market access measures that can be linked to internal capacity factors of small businesses.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.252.2-252.2
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• 2010

Biomass is considered to be a major potential fuel and renewable resource for the future. In fact, there is high potential to produce the large amount of energy from biomass around the world. In this study, to obtain basic data for practical application of wood pellet and wood pellet boiler system as heating system in agriculture, agricultural biomass resources were surveyed, pellet was made of agricultural by-product such as stem of rape, oat and rice, ricehusk and sawdust and wood pellet boiler system with capacity of 116 kW was manufactured and installed in greenhouse of $38.5m{\times}32m$. High heating value, bulk density and ash content of pellet made of agricultural by-product and efficiency and heating performance of this system was estimated. Rice straw was the largest agricultural biomass in 2005 and the total amount of rice straw converted into energy of $131.71{\times}10^{11}$ kJ. And in 2005, total amount of forest' by-product converted into energy of $29,277.05{\times}10^{11}$ kJ. High heating values of pellets made of agricultural by-products of stem and seed of rape, stem of oat, rice straw and rice husk were 16,034, 16,026, 16,089, 15,650, 15,044 kJ/kg respectively. High heating values of pellets made of agricultural by-products were 83.6% compared to that of wood pellet. Average bulk density of pellets made of agricultural by-products of stem and seed of rape, stem of oat, rice straw and rice husk was 1,400 $kg/m^3$. Ash contents of the pellets were 6.6, 7.0, 6.2, 5.5, 33% respectively. Ash content of rice husk pellet was the largest compared to other kind of pellets. To increase efficiency of agricultural pellet boiler, the boiler adopted secondary heat exchanger. The agricultural pellet boiler designed and manufactured in this study had high efficiency of 84.2% compared to the conventional agricultural pellet boiler, when water flow rate, exhaust gas temperature and average combustion furnace temperature were 39L/min, $180^{\circ}C$, $680^{\circ}C$ respectively. And pellet supplying and pausing time were 13, 43 seconds respectively. In March of 2010, prices of wood pellet, agricultural tax free diesel, diesel, kerosene were 350 won/kg, 811 won/L, 1,422 won/L, 976 Won/L respectively. Also in terms of energy, prices per same heating value were 77.8, 90.1, 158, 108.4 Won/Mcal. Energy saving rate of wood pellet was 16, 50, 39% compared to agricultural tax free diesel, diesel and kerosene respectively.

• Journal of the Mineralogical Society of Korea
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• v.21 no.2
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• pp.161-175
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• 2008

The soil developed from volcanic ash in Jeju Island, Korea, were classified as typical Andisols. The soils had acidic pH, high water contents, high organic matters and clay-silty textures. The crystalline minerals of the samples were mainly composed of ferromagnesian minerals such as olivine and pyroxene, and iron oxides such as magnetite and hematite derived from basaltic materials. A large amount of gibbsite was found at the subsurface horizon as a secondary product from the migration of excessive aluminum. In addition, our study has shown that considerable amounts of poorly ordered minerals like allophane and ferrihydrite were present in Jeju soils. The contents of $SiO_2$ were lower than those of other soil orders, but $A1_2O_3$ and $Fe_2O_3$ contents were higher. These results are some of the important chemical properties of Andisols. The contents of heavy metals were in the range of $84{\sim}198$ for Zn, $56{\sim}414$ for Ni, $38{\sim}150$ for Co, $132{\sim}1164\;mg\;kg^{-1}$ for Cr, which are higher than the worldwide values in most of the soils. Some soil samples contained relatively high levels of Cr exceeding 1000 mg/kg. Mean reduction capacity of the Jeju soils was $6.53\;mg\;L^{-1}$ reduced Cr(VI), 5.1 times higher than that of the non-volcanic ash soils from inland of Korea. The soil reduction capacity of the inland soils had a good correlation with total carbon content (R = 0.90). However, in spite of 20 times higher total carbon contents in the Jeju soils, there was a week negative correlation between the reduction capacity and the carbon content (R = -0.469), suggesting that the reduction capacity of Jeju soils is not mainly controlled by the carbon content and affected by other soil properties. Correlations of the reduction capacity with major elements showed that Al and Fe were closely connected with the reduction capacity in Jeju soil (R = 0.793; R = 0.626 respectively). Moreover, the amounts of Ni, Co and Cr had considerable correlations with the reduction capacity (R = 0.538; R = 0.647; R = 0.468 respectively). In particular, in relation to the behavior of redox-sensitive Cr, the oxidation of the trivalent chromium to mobile and toxic hexavalent chromium can be restricted by the high reduction capacity in Jeju soil. The factors controlling the reduction capacity in Jeju soils may have a close relation with the andic soil properties explained by the presence of considerable allophane and ferrihydrite in the soils.

• Korean Journal of Construction Engineering and Management
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• v.23 no.3
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• pp.66-73
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• 2022

In order to induce users to purchase excellent products in the water industry that satisfy the technical standards of excellent products, in this study, it is to present the advantages of the cost aspect of the pumps as the objective basis. It will be to promote technology development of domestic water companies and to create a virtuous cycle structure in the water industry. In order to present an objective basis for the merits in terms of cost, an economic evaluation was conducted through life cycle cost analysis. For the LCC analysis, initial cost (pump cost and installation cost), operation cost (energy cost and maintenance cost) and demolition cost (disposal cost and residual value) are searched and calculated. As the results of comparison on two capacity of pumps, the energy cost of the excellent pump is 212 million KRW lower than the that of general pump in the large pump. The cost of excellent pump was 17 million KRW lower than that of general pump in small capacity pump. As the results of sensibility test, if the product is developed in the direction of improving pump efficiency and increasing the replacement cycle of consumables, it is predicted that the effect on LCC will be large.