• Journal of Digital Convergence
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• v.10 no.2
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• pp.25-36
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• 2012

Over the last few years, despite the government's ongoing efforts for cooperative relationship between large firms and small and medium-sized enterprises(SMEs), their effectiveness is limited. In addition, the academic researches for addressing practical policy alternatives are also insufficient. This study aims to suggest the practical policies for cooperative relationship between large firms and SMEs. To this end, we suggest typology to know how collaboration process between large firms and SMEs for technology commercialization project with the utilization of dimensions of technology and marketing cooperaton is, and analyse the characteristics of each type, and examine the present situation of collaboration between large firms and SMEs in Korea and then finally, derive government policy guidelines. Through this research, we suggest theoretical framework to reinforce national industry competitiveness under growing global competition through suggesting how SMEs take survival basis, and also how large firms collaborate with SMEs.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.4
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• pp.373-378
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• 2011

The freeze desalination cycle with seawater heat pump system is simulated and designed for the basic data for the design of freeze desalination system. The basic model of seawater heat pump system is refrigeration cycle and indirect freeze desalination method is used for seawater desalination. The cycle performance of seawater heat pump such as COP, compressor work, condensing capacity was analyzed and the desalination performance such as fresh water productivity and energy per unit fresh water productivity was compared with respect to the seawater temperature of condenser inlet and ice ratio in the evaporator. The compressor work and condensing capacity decreased with respect to the decrease of seawater inlet temperature. The energy per unit fresh water productivity in case of $8^{\circ}C$ seawater inlet temperature showed 28.9% lower than that of $20^{\circ}C$.

• Microbiology and Biotechnology Letters
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• v.17 no.4
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• pp.349-357
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• 1989

Uncooked starch can be effectively saccharified in an enzyme reaction system containing attrition-milling media. To develope the high efficiency bioattritor, an agitated bead type bioreactor was constructed, and its effectiveness was evaluated. The optimal operation condition of bioattritor was found to be 300 g glass bead/L, 200 rpm, standard type impeller for 220 g/L of uncooked corn starch. The torque under the various operational conditions were also measured. The interrelation-ship between energy consumption for agitation of attrition-milling media and enhanced extent of saccharification of uncooked starch was evaluated, Power consumption was measured to be around 1.53 watt/L under the optimal operation condition. The attrition coupled enzyme reaction system is identified to tie a very excellent energy saying process for saccharification of uncooked starch, and seems to have a bright prospect of industrial application.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.1
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• pp.89-99
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• 2020

This study analyzed the load and the consumed power characteristics of a potato harvesting operation in a dry field. The potato harvesting operation was performed using an underground crop harvester mounted on an agricultural tractor with a rated engine power of 23.7 kW. The rotational speeds and the torque of the engine output shaft, rear axle, and power take-off (PTO) shaft were measured under various working conditions. The load spectrum and the consumed power were analyzed using the measured data. The results show that the consumed power of the rear axle increased as the working speed increased, while that of the PTO shaft decreased. The consumed power of the engine output shaft showed a similar trend with that of the PTO shaft, but the torque deviation was larger in the load spectrum. The results of previous studies were used to compare herein the consumed power and the load characteristics of the harvesting, rotary, and plow operations in a dry field. PTO and tractive power were highly consumed in the plow and rotary operations, respectively. The consumed power of the PTO shaft and the rear axle in the harvesting operation were 29-41% and 18-23% of the engine power, respectively. Compared to those in the rotary and plow operations, the engine power was relatively evenly distributed to the PTO shaft and rear axle in the harvesting operation.

• KSBB Journal
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• v.4 no.3
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• pp.215-220
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• 1989

To develop an attrition coupled enzyme reactor with high efficiency-low energy consumption for saccharification of insoluble biomass, a 5L horizontal paddle type bioreactor was constructed and its performance was evaluated. The optimal condition for saccharification of 50g $\alpha$ -cellulose/L was found to be 200rpm with 500g of 3mm glass bead. Especially, the horizontal paddle type bloreactor was very effective for saccharification of high concentration of insoluble cellulose, in which around 72% of $\alpha$ -cellulose was saccharified for 75g $\alpha$ -cellulose/L, and even up to 70% for 100g of $\alpha$ -cellulose/L after 24hours. Under the optimal condition, the power consumption was measured to be around 1.7watth/g. Horizontal paddle type bioreactor seems to have an appropriated structural feature for industrial scale operation and to be an effective and energy saving attrition coupled enzyme reactor.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.11
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• pp.3253-3259
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• 2009

In this study, a computer simulation has been performed for the refrigeration cycle using mixed refrigerants in order to decrease the process stream temperature to $-20^{\circ}C$. Refrigerant supply temperature was assumed to be $-30^{\circ}C$ considering the temperature difference as $10^{\circ}C$ with process stream. Peng-Robinson equation of state model was selected for the computer simulation. A new alpha function proposed by Twu et al was used for an accurate prediction of pure component vapor pressure experimental data. One fluid mixing rules were used for the estimation of mixture vapor-liquid equilibria calculations. A commercial process simulator, PRO/II with PROVISION was utilized for the simulation of the overall refrigeration process. In order to minimize the compressor power consumption, we have optimized the two-stage compression system by varying the first stage compressor outlet pressure. Finally, we could obtain the minimum total power 755.7kW at the first stage compressor outlet pressure, 6 bar.

• Korean Chemical Engineering Research
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• v.53 no.2
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• pp.174-180
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• 2015

The flow pattern and the solid-liquid mass transfer coefficient in figure-eight shaking vessels were observed by experimental method. The flow patterns, mixing time, power consumption and mass transfer coefficient in the figureeight shaking vessels changed irregularly with increase in the shaking frequency. Any frequency, even in the Fr = 0.095 or more became clear experimentally. The region of the optimum operating condition of the figure-eight shaking was larger than that of the reciprocal shaking. The solid-liquid mass transfer coefficient was correlated with the same correlation as that of the rotary shaking vessel of existing. The gas-liquid mass transfer coefficient of the figure-eight shaking vessel was also correlated with the same type of correlation as that of the rotary shaking vessel of existing.

• Solar Energy
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• v.14 no.2
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• pp.39-50
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• 1994

Experiments have been conducted to measure the heat transfer coefficient and pressure drop in fluidized bed double pope heat exchangers with smooth tube and longitudinal finned tube. The effect of particle size(alumina beads; do=0.41, 0.54, 0.65, 0.77 mm) and static bed height on the heat transfer coefficient has been evaluated in terms of pumping power. The heat transfer coefficient for the smooth tube and finned tube heat exchangers has been compared with single phase double pipe heat exchanger. Results show that the heat transfer coefficients for the finned tube in $2.96{\sim}3.45$ times higher than the smooth tube. The heat transfer coefficients for the fluidized bed heat exchanger is higher than the single phase heat exchanger for the most of pumping power range tested. The maximum increase in the heat transfer coefficient for fluidized bed is 91.3% for the smooth tube and 127.1% for the finned tube.

• Journal of Drive and Control
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• v.21 no.2
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• pp.44-52
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• 2024

In this study, we predicted PTO power requirements based on torque predicted by the discrete element method and the multi-body dynamics coupling method. Six different scenarios were simulated to predict PTO power requirements in different soil conditions. The first scenario was a tillage operation on cohesionless soil, and the field was modeled using the Hertz-Mindlin contact model. In the second through sixth scenarios, tillage operations were performed on viscous soils, and the field was represented by the Hertz-Mindlin + JKR model for cohesion. To check the influence of surface energy, a parameter to reproduce cohesion, on the power requirement, a simple regression analysis was performed. The significance and appropriateness of the regression model were checked and found to be acceptable. The study findings are expected to be used in design optimization studies of agricultural machinery by predicting power requirements using the discrete element method and the multi-body dynamics coupling method and analyzing the effect of soil cohesion on the power requirement.

• Proceedings of the Korean Society of Organic Agriculture Conference
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• 2005.12a
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• pp.37-45
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• 2005

본 시험은 관행(일반)과 유기조사료 생산에서 여름 사료작물인 옥수수, 수수 및 수단그라스의 생산량과 생산비를 비교하기 위하여 실시하였다. 관행(일반)생산에 옥수수, 수수 및 수단그라스의 건물수량은 각각 14,265 kg/ha, 23,780 kg/ha 및 20,867kg/ha로 옥수수에 비하여 수수는 67%, 수단그라스는 46% 수량이 많았다. 관행 옥수수, 수수 및 수단그라스의 ha당 생산비는 3,167,346원, 2,579,545원 및 2,696,298원이었으며, 건물 1kg 생산비는 관행 옥수수, 수수 및 수단그라스가 각각 222원, 110원 및 131원으로 옥수수의 생산비가 수수보다 2배 많이 소요되었다. 그리고 생산비 중에서 가장 많은 비중을 차지하는 것은 지대(땅값)로 35.3%에서 37.6%를 차지하였으며, 다음은 비료(퇴비포함), 노동력 순으로 나타났다. 유기조사료 생산에서 옥수수, 수수 및 수단그라스의 건물수량은 각각 8,965 kg/ha, 17,719 kg/ha 및 15,260kg/ha로 옥수수에 비하여 수수는 98%, 수단그라스는 70% 수량이 많았다. 유기 옥수수, 수수 및 수단그라스의 ha당 생산비는 2,989,327원, 2,593,082원 및 2,660,894원이었으며, 건물 1kg 생산비는 유기 옥수수, 수수 및 수단그라스가 각각 334원, 149원 및 176원으로 옥수수의 생산비가 수수보다 2배 이상 많이 소요되었다. 그리고 유기 여름사료작물의 생산비 중에서 가장 많은 비중을 차지하는 것은 관행과 마찬가지로 지대(땅값)였으며, 다음은 퇴비생산, 노동력 순으로 나타났다. 관행 및 유기 여름사료작물의 생산량 비교에서 관행이 유기보다 건물수량은 5,656 kg/ha, TDN 수량은 3,531 kg/ha 많았다. 한편 관행 및 유기 여름사료작물의 생산비에서는 면적당 생산비는 관행이 많았으나 건물 TDN 1kg 당 생산비는 유기 여름사료작물이 관행보다 건물은 66원, TDN은 100원 많이 소요되었다. 이상의 연구결과를 종합해볼 때 관행 생산 여름 사료작물이 유기생산보다 생산량과 단위면적당 생산비는 많았으나 kg당 생산비는 유기 생산이관행보다 많이 소요되었다. 생산비 중에서 가장 많은 비중을 차지한 것은 지대(땅값)였으며, 다음은 퇴비와 노동력이 가장 많은 비중을 차지하여 농가의 낙농경영에 가장 어려운 문제는 땅값, 퇴비생산, 노동력으로 평가되었다.