• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.25 no.2
• /
• pp.32-42
• /
• 2011

In this paper to compare the economical efficiency of light sources for a tunnel lighting, we define a model tunnel and design tunnel lighting. And to examine economical efficiency of various tunnel lightings we compare the lighting expenses of tunnels. The results shows high pressure sodium lamps are more economical than fluorescent lamps.

• Proceedings of the KAIS Fall Conference
• /
• 2007.05a
• /
• pp.112-115
• /
• 2007

Currently an increase in domestic sewage and industrial wastewater causes serious water pollution in Korea. To solve water pollution problems, conventional activated sludge (CAS) system is generally used in wastewater treatment plant but this process is so ineffective in nitrogen and phosphorus. Even if CAS system is the major process, it must be improved instantly so as to remove nitrogen and phosphorus. Otherwise, the serious water pollution problems can't be resolved with CAS system. Therefore this study focused on the comparison of the treatment characteristics between ASA system and CAS system. And also the mass balance of each process of ASA system. The results from operating advanced step aeration (ASA) system indicated that the removal efficiency of BOD, COD, and SS was 89.9%, 74.5%, and 89.0% respectively. In comparison, the removal efficiency of BOD, COD, and SS for CAS system was 89.5%, 71.8%, and 89.5% respectively. In addition to the results, the TN removal efficiency of ASA system was 76.5% comparing to 32.7% of CAS system. It was concluded that the TN removal efficiency of ASA system was 44% higher than CAS system. And the TP removal efficiency was 81.4% in ASA system comparing to 25.2% in CAS system. It also means that over 56% of TP was removed in ASA system comparing to CAS system.

• Journal of the Korean Society for Precision Engineering
• /
• v.12 no.3
• /
• pp.32-41
• /
• 1995

In the analysis of metal forming processes by the finite element method, there are many numerical instabilities such as element locking, hourglass mode and shear locking. These instabilities may have a bad effect upon accuracy and convergence. The present work is concerned with improvement of stability and efficiency in two-dimensional rigid-plastic finite element method using various type of elemenmts and numerical intergration schemes. As metal forming examples, upsetting and backward extrusion are taken for comparison among the methods: various element types and numerical integration schemes. Comparison is made in terms of stability and efficiency in element behavior and computational efficiency and a new scheme of adaptive directional reduced integration is introduced. As a result, the finite element computation has been stabilized from the viewpoint of computational time, convergency, and numerical instability.

• Journal of the Korean Solar Energy Society
• /
• v.27 no.4
• /
• pp.77-85
• /
• 2007

With the increase in the demand for sustainable and environment-friendly development all over the world, it becomes an urgent issue for Korea to reduce $CO_2$ emission. Since building industry accounts for about 40% of international energy and resource consumption and $30{\sim}40%$ of $CO_2$ emission, it is essential to prepare for energy-efficient building. This study aims to seek for improvement direction for a domestic Building Energy Efficiency Rating System through the comparison with foreign systems. Two foreign building energy rating systems which have the similar application scope with domestic one, HERS(Home Energy Rating System) and SAP(Standard Assessment Procedure)2005 were selected. As compared with foreign systems, we intended to suggest improvement direction for effective application of Building Energy Efficiency Rating System in Korea.

• International Journal of Advanced Culture Technology
• /
• v.3 no.2
• /
• pp.67-76
• /
• 2015

This paper aims to study and design of Organic Rankine Cycle (ORC) Machine using Isopentane as working fluid expanding through Tesla turbine. The study on ORC machine expanding through Tesla turbine has result on the efficiency of Tesla turbine. In addition, Thermodynamics theory on isentropic efficiency proved to be a successful method for overcoming the difficulties associated with the determination of very low torque at very high angular speed. By using an inexpensive experiment device and a simple method, the angular acceleration method, for measuring output torque and power in a Tesla turbine is able to predict a tendency of output work. The experiments using two Tesla turbine sizes, the first size is 1.6 bigger than the second one. In comparison with the first size, the tesla turbine can produce power output more than 62% of the second size. Further study on the machine can be developed throughout the county due to its low cost and efficiency.

• Proceedings of the KSR Conference
• /
• 2002.05a
• /
• pp.549-554
• /
• 2002

Recently, interest in hygiene has been arouse in the health care field. Consequently, Filters with antibacterial agent applied to improve air quality by sterilizing bacteria, fungi, etc. We actually installed antibacterial air filter containing 2.5wt%Ag zeolite on the air intake route to air-conditioner in passenger cu, and evaluated filter's performance on antibacterial effect. By the microbe liquid spattering method, we found that the antibacterial air filter has notably sufficient antibacterial efficiency against standard strains and wild type strains. Antibacterial effect was observed at whole area of filter media by zone of inhibition test. The evaluation of microbe quantity was conducted through mixing dilution plate culture method. In comparison with ordinary filter, the amount of germs attached on antibacterial air filters was larger. The amount of germs attached on ordinary filters was very small since ordinary filters contained less dust. In comparison in antibacterial air filter with thickness, the amount of germs attached on 9mm filter was smaller than that of on 6mm filter. i.e. thicker filter, superior efficiency.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.61 no.1
• /
• pp.70-74
• /
• 2012

Copper die casting motor (CDM) has a better design flexibility than aluminium die casting motor (ADM) because of the higher conductivity of copper. However, CDM has an economic and manufacturing weak point due to high copper price and high melting temperature compared to ADM. This paper describes a comparison of the design parameters, specifications, performances and material cost between CDM and ADM of 5.5kW_6P.

• 한국신재생에너지학회:학술대회논문집
• /
• 2010.11a
• /
• pp.38.2-38.2
• /
• 2010

Biomimetc is a new domain of learning that proposes a solution getting clues from nature. There seems to be a sign of this phenomenon in fields of Renewable Energy. Foe example, Wind power was imitate the whale's fin that was improve efficiency of generating energy. This study focused on the photovoltaic generation as the instance of applying biomimetic. Efficiency is the most important factor in field of Photovoltaic generation. When given solar cell taking the sun light, most important fields of the study are absorb more light and increase the quantity of generation. For improving efficiency, the solar cell were builded up textures of taking a pyramid form, such a surface structure taking a role for remaining the light. This effects do the role as increasing absorbing efficiency. Such phenomenon calls Light Trapping, locking up the light on the surface of solar cell for a long time. Light is a vital factor to plants in the nature. Plants grow up through the photosynthesis that absorbing light for growth and propagation. So, plants make a effort how can absorb more the light in poor surroundings. This study set up a goal that imitates the minute surface structure of plants and applies to the existing solar cells's surface structure, so it can improve the efficiency of absorbing light. We used Light Tools software analyzing geometrical optics to analyze efficiency about new designed textures on the computer. We made a comparison between existing textures and new designed textures. Consequently, new designed textures were advanced efficiency, absorbing rates of light increasing about 7 percent. In comparison with existing and new textures, advancing about 20 percent in the efficient aspect.

• Journal of Ginseng Research
• /
• v.3 no.1
• /
• pp.1-34
• /
• 1979

Our nation is confronted with the situation that the rice, a principal food, short of some essential amino acids, leads to imbalanced meals insufficient in the nutrient of Protein, to bring many difficulties in the elevation of nutritional state in our nation. While. our country has been produced much amounts of Panax Ginseng roots which has a stimulating effects on the metabolism of protein, lipid and nucleic acids in the body. And the leaf and trunk of Panax Ginseng were also produced a considerable amounts as the by-products. Author believe that these by-products (leaf and trunk) of Panax Ginseng might have some components possessing simillar activity with Panax Ginseng root although the quantity and qualify of the functional components may more or less be different. Therefore, this study was demised to observe the supplemental effect of the Panax Ginseng-by-Products on the dietary protein efficiency and nutritional state of rats. The feeds used for this experiment were rice containing 30% barely, fish four, and the leaf, trunk and small root of the Panax Ginseng, and the contents of the general nutrients including protein, lipid and carbohydrate etc. in each feed were analyzed for the combination of each feed. And, being based on analytical values of Protein in food. fish Pour as Protein source was added were rice containing 30% barely to be include 8.6 to 8.7%, 12%, 15% and 18% of protein. Then 2% of the leaf, trunk or small reef of Panax Ginseng was supplemented into each of above protein diet group, ton 16 kinds of diets were Prepared. The male albino rats from a Pure strain, weighing 70g to 80g. were used for experimental animals. They were maintained with coresponding fist for f and 8 weeks, and the growth rate, consumption of diets and protein, efficiency of feed and Protein in animals were determined. The lipids, proteins and cholesterols in serum and liver were also determined quantitatively after they were sacrificed in coresponding term. The results obtained are summarized as follows: 1. Body weigh of diet group containing 8.6 to 8.7%,12%, and 15% of protein are increased remarkably by supplement of 2% of the leaf or small root of Panax Ginseng in comparison with each of controls. But this tendency could not observed in diet group containing 18eA Proteins. 2. Feed efficiency showed same tendency in comparison with changes of gained body weight. Specially, in each of diets containing 8.7%, 12%, 15% and 18% of Proteins, supplement of the leaf of Panax Ginseng showed the better feed efficiency than supplement of the trunk or small root. 3. In feeding group for 8 weeks, protein efficiency showed worst efficiency in diet containing 18% proteins and showed the best efficiency was the diet group containing 12% Proteins. And the efficiency was improved according to supplement of the leaf of Panax Ginseng. 4. Nitrogen contents in serum and liver did not show large differences each other in all diet groups. But contexts of total cholesterol and 1ipid were decreased markedly in diet groups containing 12%, 15% and 18% of proteins in comparison with diet group containing 8.6% to 8.8% of proteins.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.24 no.5
• /
• pp.345-350
• /
• 2011

This paper was carried about optimization for high efficiency of point contact solar cell. We have studied on the characteristics of power converter according to each parameter for the optimization for high efficiency of point contact solar cell on this study. We have 25.1352% of convert efficiency after adapt optimal parameters as mentioned in point body and superior conclusion is drawn by comparison with general efficiency has within 20%. At this time, the value of parameter is 100 um cell pitch, 0.01 um AR coating, 0.9 um N+ FSF thickness., etc. This study will continue to go on for optimization for efficiency in future, as it looks now, the results of this study would contribute to the business of high efficiency of point contact solar cell.