• Journal of Biosystems Engineering
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• v.9 no.2
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• pp.65-73
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• 1984

While most of researches on the performance of high temperature grain dryer have dealt mainly with improving dryer capacity and drying speed during the last twenty years, energy efficiency, in fact, has not been emphasized. Current fuel supplies and energy cost have shifted the emphasis to reducing the energy consumption for grain drying while maintaining dryer capacity and grain quality. Since the energy input for drying is relatively large, the recovery and reuse of at least part of the exhaust energy can significantly reduce the total energy consumption in existing drying systems. Unilization of exhaust heat in grain dryer either through direct recycling or by a thermal coupling in heat exchanger have been subject of a number of investigators. However, very seldom research in Korea has been done in this area. Three drying tests(non-recycling, 0.22 recycle ratio, and 0.76 recycle ratio)were performed to investigate the thermal efficiency and heat loss factors of continuous flow type dryer, and to analyze the effect of recycle ratio (weight of exhaust air recycled/total weight of input air) on the energy requriements for rough rice drying. The test results showed that when the exhaust air was not recycled, the energy lost from furnace was 15.3 percent of input fuel energy, and latent and sensible heat of exhaust air were 61.4 percent and 11.2 percent respectively. The heat which was required in raising grain temperature and stored in dryer was relatively small. As the recycle ratio of exhaust air was increased, the drying rate was suddenly decreased, and thermal efficiency of the kerosene burner was also decreased. Drying test with 0.76 recycle ratio resulted in 12.4% increase in fuel consumption, and 38.4% increase in electric power consumption as compared to the non-recycled drying test. Drying test of 0.22 recycle ratio resulted in 6.8% saving in total energy consumption, 8.0% reduction in fuel consumption, and 2.5% increase in electric power consumption as compared to the non-recycled drying test.

• International Journal of Computer Science & Network Security
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• v.24 no.2
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• pp.53-58
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• 2024

This paper presents a novel miniaturized 3-D cubic antenna for use in wireless sensor network (WSN) application. The geometry of this antenna is designed as a cube including a meander dipole antenna. A truly omnidirectional pattern is produced by this antenna in both E-plane and H-plane, which allows for non-intermittent communication that is orientation independent. The operating frequency lies in the ISM band (centered in 2.45 GHz). The dimensions of this ultra-compact cubic antenna are 1.25*1.12*1cm3 which features a length dimension λ/11. The coefficient which presents the overall antenna structure is Ka=0.44. The cubic shape of the antenna is allowing for smart packaging, as sensor equipment may be easily integrated into the cube hallow interior. The major constraint of WSN is the energy consumption. The power consumption of radio communication unit is relatively high. So it is necessary to design an antenna which improves the energy efficiency. The parameters considered in this work are the resonant frequency, return loss, efficiency, bandwidth, radiation pattern, gain and the electromagnetic field of the proposed antenna. The specificity of this geometry is that its size is relatively small with an excellent gain and efficiency compared to previously structures (reported in the literature). All results of the simulations were performed by CST Microwave Studio simulation software and validated with HFSS. We used Advanced Design System (ADS) to validate the equivalent scheme of our conception. Input here the part of summary.

• Journal of the East Asian Society of Dietary Life
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• v.18 no.2
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• pp.242-252
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• 2008

The objective of this study was to suggest a new efficiency measurement indicator for evaluating the menu management efficiency of decision making units(DMUs) in contract-foodservice operations and to determine the relationship between the DEA(data envelopment analysis) menu efficiency score and menu factors. The results of applying DEA revealed relatively efficient types of service and frequency of meals. The efficient service was shown as a self-service type that operates Monday to Saturday. The considered menu factors included meal price, food cost per meal, meal counts, number of menu items, use of favorite menu use, forecasting error, accuracy of ordering, ratio of inventory, ratio of food loss, use of processed foods and use of prepared vegetables are considered. There were significant correlations between the DEA score and meal price, meal counts, number of menu items, ratio of food loss, accuracy of ordering and use of processed foods respectively. According to the regression results, menu price had a positive influence on the DEA menu efficiency score, and food cost per meal and the use of prepared foods had negative influences respectively.

• Journal of the Korean institute of surface engineering
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• v.37 no.2
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• pp.86-91
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• 2004

Effect of potassium formate, glycine and oxalic acid in a sulfate solution on the deposit composition and current efficiency of trivalent chromium plating was studied. The trivalent chromium layers prepared by solutions with potassium formate, glycine and oxalic acid contain a few carbon inside. The solutions containing potassium formate, glycine and oxalic acid are relatively stable with pH change. The solution with the potassium formate shows 6-30％ current efficiency with current density, whereas, the solutions with oxalic acid and glycine show about 5％ current efficiency, respectively. The improved current efficiency is related to enough supply of chromium ions to the electrode due to the increase of pH at the front of electrode.

• Food Science of Animal Resources
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• v.20 no.1
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• pp.30-35
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• 2000

The method used to remove cholesterol from egg by using $beta$-cyclodextrin was relatively stable and efficient. The aim of this study was to cost down by recycling $\beta$-cyclodextrin used to remove cholesterol from egg yolk because $\beta$-cyclodextrin was expensive. The solvents used to separate $\beta$-cyclodextrin from $\beta$-cyclodextrin complex containing egg yolk cholesterol were butanol, chloroform, ether, hexane, methanol, 2-propanol and their mixture. The ratio of solvent and complex varied from 2 : 1 to 10 : 1. The condition of mixing time and temperature varied from 30 to 60$^{\circ}C$ and from 10 minutes to 3 hours to remove cholesterol from $\beta$-cyclodextrin complex. When the ratio of choloroform and methanol was 1 : 1, the removal efficiency of cholesterol was 98.8%. The efficiency of cholesterol removal was improved when the ratio of solvent : complex increased to 4 : 1. When mixing time and temperature was up to for 1hr, at 50$^{\circ}C$ respectively, the efficiency of cholesterol removal improved to 99%. It concluded that the efficiency of cholesterol removal of 50% renewed one contained $\beta$-cyclodextrin were 81.1% while the cholesterol removal efficiency of 100% renewed $\beta$-cyclodextrin was 24% if cholesterol removal efficiency of new $\beta$-cyclodextrin were 100%.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.1
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• pp.13-19
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• 2017

Relatively low efficiency in anaerobic digestion process is mainly caused by unproper mixing method. In this study, tray motion type agitator was applied in actual anaerobic digestion tank in order to improve the digestion efficiency, equalize the flow velocity distribution and energy saving. The impeller of tray motion type agitator was reciprocated vertically. Gas lift type agitator and tray motion type agitator appears almost same mixing efficiency include digestion rates. However, tray motion type agitator have shown that lower energy consumption compared to the conventional gas lift type agitator. Implementation of tray motion type agitator in the anaerobic digestion tanks contributed to the stabilization of mixing environment, efficiency and energy efficiency of the tank.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.579-581
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• 1994

The efficiency optimized speed control system of Induction Motor is proposed At light load, the IM has poor efficiency because of relatively high magnetizing current. In this paper, by employing the field oriented control with flux controller which the motor is operated at optimal slip frequency, the proposed system has good performance and high efficiency. In simulation, the performance, loss and efficiency of the proposed optimal flux control system are compared with those of the coventional constant flux operation. In conclusion, the efficiency is raised by 2.55%, the loss is decreased by 0.1[p.u].

• Ecology and Resilient Infrastructure
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• v.1 no.2
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• pp.102-108
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• 2014

Studies of non-point pollutant treatment facilities have widely been conducted for a decade, but natural non-point pollutant treatment facilities implemented on roads have not been carried out for the removal efficiency of non-point pollution sources. This study analyzed the removal efficiency of non-point pollution sources from constructed wetlands using monitoring and event mean concentration method. As a result of this study, removal efficiency of general non-point pollution sources as TSS, COD, BOD is relatively good, but removal efficiency of TN, TP, Cr, Zn, Pb is very small or nothing.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.30 no.1
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• pp.96-101
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• 2016

In this paper, We investigate the number of 795 transformer in the private electrical facilities and analyze the annual load factor. The results show that the annual load factor of transformer is 20.16% in manufacturing industry, education services(school) is 9.59%, retail and wholesale services is 19.68%, resort and leisure industry is 10.93%, office building is 13.10%, and apartment houses is 14.69%. Education services, resort and leisure industry are being operated with a very low annual load factor. The relatively small capacity of less than 500kVA transformer also been analyzed that is being operated with a low load factor. Therefore, In order to minimize the power loss of the transformer, it is advisable to complement the Transformer Efficiency Management system to be designed the efficiency is good transformer when the load is low. Analysis results will be used as the basis for the provision of transformer efficiency management system and be used High-efficiency transformers promotion system.

• The KSFM Journal of Fluid Machinery
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• v.17 no.5
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• pp.19-26
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• 2014

The cross flow turbine attracts more and more attention for its relatively wide operating range and simple structure. In this study, a novel type of micro cross flow turbine is developed for application to a step in an irrigational channel. The head of the turbine is only H=4.3m and the turbine inlet channel is open ducted type, which has barely been studied. The efficiency of the turbine with inlet open duct channel is relatively low. Therefore, a guide nozzle on the turbine inlet is attached to improve the performance of the turbine. The guide nozzle shapes are investigated to find the best shape for the turbine. The guide nozzle plays an important role on directing flow at the runner entry, and it also decreases the negative torque loss by reducing the pressure difference in Region 1. There is 12.5% of efficiency improvement by attaching a well shaped guide nozzle on the turbine inlet.