• Fashion & Textile Research Journal
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• v.7 no.1
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• pp.101-105
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• 2005

This study surveys the warp and weft tension differences between projectile and air-jet looms and analyses the mechanical properties of worsted fabrics for garment with relation of these loom characteristics using KES-FB system. The paper is divided by two parts. In the 1st paper, the worsted fabric is woven as 5 harness satin weave using 1/40 Nm sirofil worsted warp yarn and 1/30 Nm worsted weft yarn by projectile(Sulzer) and air-jet looms(Picanol PAT and OMNI), respectively. The weavability is also analysed by measuring warp tension variation according to the warp position and weft tension of 3 kinds of looms. The relationship between shed amount and the warp tension is surveyed, and the relationship between end breaks and warp and weft tensions is also discussed.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.1967-1972
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• 2008

Reburning is an efficient combustion technology to reduce nitrogen oxide by injecting hydro-carbon fuel to the downstream of the main combustion. In this paper LPG has been used not only as main fuel but also as reburn fuel and air was used as an oxidizer with 15kW swirl burner. Experimental studies have been done to evaluate effect of reburning for NOx reduction. Also to examine the effect of the amount of burnout air for complete combustion by reburn fuel on NOx reduction, test was conducted by reducing the amount of burnout air. Computational fluid dynamic (CFD) simulation was performed using the commercial CFD code FLUENT 6.3 to simulate experimental results and investigate the thermo-chemical characteristics. An evaluation of reaction models for swirl burner has been carried out for propane-air with two step finite-rate eddy-dissipation model in FLUENT.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1436-1441
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• 2004

Achieving the maximum blasting efficiency with minimum abrasive consumption is a critical concern in surface preparation stage of shipbuilding and offshore industry. Increasing the abrasive flow rate beyond the optimum point results in a major reduction in productivity even though the amount of abrasive used is larger. So, this study is intend to find out the optimum abrasive-to-air mixing ratio which can make a significant improvement in blasting efficiency and remarkably reduce the amount of abrasive used. From the test results, it can be identified that as the abrasive feeding rate is increased linearly, blasting efficiency is increased to a maximum point and then gradually decreased in the form of a bell-shaped.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.23 no.5
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• pp.361-377
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• 1994

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2005.11a
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• pp.165-166
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• 2005

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.6 no.2
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• pp.155-165
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• 1994

In this study, the following factors are investigated from experiments for a vertical parallel plate heat exchanger under the frosting condition ; the growth of frost layer, the characteristics of heat and mass transfer, the change of mass flow rate of the air passing through the heat exchanger, and the pressure drop of the air in the heat exchanger. The amount of heat and mass flux of water vapor transferred from the air stream to the heat exchanger surface is large at the early stage of frosting and then decreases dramatically, and the extent of decreasing rate becomes moderate with time. The frost layer formed near the inlet of the heat exchanger is thicker and denser than that formed near the outlet. It is found that the gradient of the amount of frost along the flow direction increases with time. In the early period of frost formation, the thermal resistance between the air and the cooling plate increases dramatically and then the extent of change decreases with time. Initially the convective thermal resistance is dominant. Then, while the convective thermal resistance decreases with time, the conductive thermal resistance continues to increase with time and finally the conductive thermal resistance becomes dominant.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.64 no.4
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• pp.303-307
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• 2015

The effects of additive such as $H_2O_2$ in KOH electrolyte solution for the Aluminum/Air fuel cell were investigated with regard to electric power characteristics. The power generated by a Al/Air fuel cell was controlled by the KOH electrolyte solution and $H_2O_2$ depolarizer. Higher cell power was achieved when higher KOH electrolyte concentration and higher $H_2O_2$ depolarizer amount. The maximum power was increased by the increase amount $H_2O_2$ depolarizer, it was found that $H_2O_2$ depolarizer inhibits the generation of hydrogen and the polarization effect was reduced as a result. Internal resistance analysis was employed to elucidate the maximum power variation. Higher internal resistance created internal potential differences that drive current dissipating energy. In order to improve the output characteristics of the Al/Air fuel cell, it is thought to be desirable to increase the KOH electrolyte concentration and increase the $H_2O_2$ addition amounts.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.2_1
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• pp.149-159
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• 2022

Biomass is material that is comprehensive of carbonaceous materials from plants, crops, animals, and algae. It has been used as one of heating fuel since the beginning the emergence of human beings. Since biomass is regarded as carbon-neutral energy source, it has recently been attracting attention as an energy source that can replace fossil fuels. The most widely applied field is distributed power generation, and a method of generating electric power by driving an internal combustion engine with syngas produced by gasifier is chosen. While the composition of the syngas produced in gasifiers changes depending on the air flowing into the reactor, commercialized gasifiers so far do not control the air flowing into the reactor. When the inner pressure in reactor increases, the air sucked into the reactor is reduced. That change of amount of air makes the composition of syngas varied. Those variations of composition of syngas cause the incomplete combustion hence the power output of engine drops, which is a critical weakness of the gasification technology. In this paper, to produce the uniformly composed syngas, PID control is applied. The result was shown when the amount of air into the reactor is supplied with the constant amount using PID control, the standard deviation of caloric values of syngas is around 2[%] of its average value. Meanwhile the gasifier without PID control has the standard deviation of caloric values is around 7[%]. Therefore, Adopting PID control to supply constant air to the gasifier is highly desirable.

• Journal of Environmental Science International
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• v.17 no.8
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• pp.907-918
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• 2008

In order to monitor the impact of high temperature which is seen frequently with climate change, we investigated the monthly change in globe temperature, air temperature, mean radiant temperature and effective radiant heat flow, because the four well reflect thermal radiation from bio-meteorological aspect. Both globe temperature and air temperature showed an increasing trend every month. Compared to air temperature, globe temperature had a wider range of temperature change and was more influenced by meteorological element such as precipitation. Diurnal trends of air temperature, globe temperature and the difference between their temperature had the lowest value before the sunrise and the highest around $1300{\sim}1500$ LST, showing the typical diurnal trends. Globe temperature and the difference between their temperature had a sharp increase around $1000{\sim}1100$ LST, maintained high value until 1700 LST and then reclined, though varied by month. The difference between globe temperature and air temperature was highly dependent on the amount of precipitation and clouds. The duration in which globe temperature was higher than air temperature was the lowest in July. Therefore the amount of precipitation was the most affecting, followed by the amount of clouds and wind. In order to find out the diurnal trends of temperature in city center and city outskirts, we assumed the roof of a concrete build ing as a city center, and the grass-covered observatory of the Gimhae International Airport as city outskirts. The diurnal trends of temperature in the two sites showed a strong correlation. The highest and lowest temperature also had the same trend.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.39 no.3
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• pp.56-63
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• 2016

For air express service providers offering various express delivery services such as overnight delivery and next-business day delivery services, establishing quickly cargo loading plans is one of important issues owing to the characteristics of air express business, i.e., a short amount of time is available to complete all cargo loading operations before flight departure after receiving air express containers, pallets and bulks. On the other hand, one of major concerns in the air cargo loading planning is to make a plan that insures the stability of an aircraft to avoid take-off, flight, and landing accidents. To this end, this paper considers an air cargo loading planning problem, which is the problem of determining locations in the aircraft cargo space where air containers, pallets and bulks to be loaded while insuring the aircraft stability, motivated from DHL and Air Hong Kong. The objective of the problem is to maximize the total revenue gained from loading air express containers, pallets and bulks. To solve the problem, this paper suggests a simulated annealing algorithm to overcome impracticality of the integer programming model developed by a previous study requiring excessive computation time. The results of computational experiments show that the heuristic algorithm is a viable tool for establishing express cargo loading plans as giving robust and good solutions in a short amount of computation time. Scenario analyses are performed to investigate the effect of the current activities of air express carriers on the revenue change and to draw practical implications for air express service providers.