• Nuclear Engineering and Technology
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• v.25 no.1
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• pp.166-177
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• 1993

A simplified thermal analysis method to evaluate the maximum temperature of the CANDU 37-element fuel bundle within a fuel basket in a given spent fuel dry storage canister has been presented along with the results of sample analyses performed to examine the parametric effects of the ambient conditions on the maximum fuel temperature within a canister. To solve the multi-dimensional heat transfer problem of the complex geometry of rod bundles within a canister where three modes of heat transfer are superimposed, the CANDU spent fuel bundles stored in the dry storage canister are first replaced by equivalent concentric fuel cylinders. The simplified axi-symmetric two-dimensional multi-mode heat transfer problem of the equivalent fuel cylinders is then analyzed with an existing computer code, HEATING5, using additional input data and heat transfer correlations. A comparison between the predicted temperature profile and the mock-up test results shows that the agreement is quite satisfactory.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.8
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• pp.82-88
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• 2008

This paper describes the influence of the bridge formed between electrodes by electrolyte for tracking process. Electrolytes is made by IEC(International Electrotechnical Commission) 60589, NaCl added to deionized water as each 1, 3, 5[wt%]. The used test equipment is made according to KS(Korean Industrial Standard) C IEC 00112. It is investigated voltage, current, value of resistance and thermal image when bridge formed between electrodes on tracking process. As a result, as conductivity of electrolyte gets bigger as Joule's heat on bridge also gets bigger. But It is not over electrolyte's boiling point due to evaporation heat of electrolyte. However as conductivity of electrolyte gets bigger as the necessary time of dry band gets shorter. So dry band is existed more long time between ahead of droplet to next droplet and discharge chance at dry band gets much. Therefore tracking process gets faster.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.1
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• pp.1-9
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• 2007

Water condensate accumulated on the surface of a fin-and-tube heat exchanger significantly affects its thermal and hydraulic performance. The purpose of this study is to investigate the effect of condensate retention on the air-side heat transfer performance and flow friction. Total 12 samples of slit and plate fin-and-tube heat exchangers with varying fin spacing and number of tube rows are tested under dry and wet conditions. The thermal fluid measurements are made using a psychometric calorimeter. Frontal air velocity varies in the range from 0.7 m/s to 1.5 m/s. Using the experimental data, presented are the heat transfer coefficients in terms of Colburn j-factor and friction factor.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.11a
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• pp.230-235
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• 1996

The new concept of dry area formation based on Poisson distribution of active nucleation sites and the concept of the critical active site density is presented. A simple statistical model is developed to predict the change of slope of the boiling curve up to critical heat flux (CHF) quantitatively. The predictions by the present model are in good agreement with the experimental data. Also it turns out that the present model well explains the mechanism on how the surface wettability influences CHF.

• The Journal of Internal Korean Medicine
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• v.12 no.1
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• pp.98-104
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• 1991

I studied some important medical Literatures in order to examine the cause of Hoarse Voice and found out some facts of follows ; 1. The exogenous cause of disease in wind. 2. Wind-cold, Wind-fire, Wind-heat, Summer-heat, Heat. 3. The endogenous cause of disease is deficiency of Yin and dificiency of blood leads fire-evil was lung-dry stool dificiency of body fluid. 4. The non-exo-endogenous causes of disease is sing ballads and call out.

• Culinary science and hospitality research
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• v.24 no.1
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• pp.24-30
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• 2018

This study investigated the quality of characteristics of high-protein RTD coffee using domestic and imported skim milk powder with different heat treatment. Skim milk powders (A, B) had high-heat treatment, C had medium-heat, and D and E had low-heat treatment. The transmittance of A and B were higher than that of C, and that of C were higher than that of D and E (p<0.05). The precipitate attached on bottom of container of RTD coffee using A and B were 2.993~3.053% and higher than those (0.753~0.803%) of RTD coffee using C, D and E (p<0.05), but there was no difference between those of RTD coffee using C, D and E (p<0.05). The centrifuged precipitate of RTD coffee using A and B were 1.987~2.040% and higher than those (0.820~0.830%) of RTD coffee using C, D and E (p<0.05), but there was no difference between those of RTD coffee using C, D and E (p<0.05). The proximate composition of precipitate attached on bottom of container of RTD coffee using A, which showed the highest amount of precipitate, showed 65.7% of carbohydrate, 19.0% of protein, 4.8% of fat and 4.8% of ash in dry basis, that of RTD coffee being 72.7%, 15.1%, 7.9% and 4.3% in dry basis respectively. Protein and fat content of precipitate were lower and protein and ash content were higher than those of RTD coffee. But seeing that the most increased portion was protein, precipitation of RTD coffee appears to be attributed to heat-denatured proteins.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.8 no.1
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• pp.1-12
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• 1996

In lots of application to heat exchanger systems, closed two-phase thermosyphons are tilted from a horizontal. If the tilt angle, especially, is less than 30$^{\circ}$, the operational performances of thermosyphon are highly dependent on tilt angle. The present study was conducted to better understand such operational behaviors as mech-anni는 of phase change, and flow patterns inside a tilted thermosyphon. For experiment, an ethanol thermosyphon with a 35% of fill charge rate was designed and manufactured, using a copper tube with a diameter 19mm and a length 1500mm. Through a series of test, the tilt angle was kept constant at each of 4 different values in the range 10~25deg. and the heat supply to the evaporator was stepwisely increased up to 30㎾/$m^2$. When a steady state was established to the thermosyphon for each step of thermal loads, the wall temperature distribution and vapor temperature at the condenser were measured. The wall temperature distributions demonstrated a formation of dry patch in the top end zone of the evaporator, with a values of temperature 20~4$0^{\circ}C$ higher than the wetted surface for a moderate heat flux q≒20㎾/$m^2$. Inspite of the presence of hot dry patch, however, the mean values of boiling heat transfer coefficient at the evaporator wall were still in a good agreement with those predicted by Rohsenow's formula, which was based on nucleate boiling. For the condenser, the wall temperatures were practically uniform, and the measured values of condensation heat transfer coefficient were 1.7 times higher than the predicted values obtained from Nusselt's film condensation theory on tilted plate. Using those two expressions, a correlation was formulated as a function of heat flux and tilt angle, to determine the total thermal resistance of a tilted thermosyphon. The correlation formula showed a good agreement with the experimental data within 20%.

• Solar Energy
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• v.11 no.1
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• pp.69-77
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• 1991

A two-phase closed thermosyphon with circular fins was used as the heat transfer device for storing the thermal energy in paraffin wax. Experiments were carried out for 4, 6 and 8 fins and for various initial temperatures of the wax and power inputs. Heat transfer characteristics along the heat flow path were investigated as well as the overall performance of the system. Some of the important results are as follows:(1) The thermosyphon heat transfer coefficient and the overall heat transfer coefficient increased with the number of fins, whereas the heat transfer coefficient between the fin and the wax decreased; (2) Facilitation of heat transfer by the fins seemed to alleviate the dry-out phenomenon that had been reported to occur in case of bare thermosyphon; and (3) The horizontal fins had adverse effect of subduing a full scale convection in the wax, and the increase of the number of fins delayed the onset of local convection between the fins.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.627-632
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• 2006

An experimental study is conducted to investigate the effect of the tube row and fin spacing on the air-side heat transfer and friction characteristics of fin-tube heat exchangers with slit fin pattern. A total of twelve samples of fin-tube heat exchangers with the nominal tube diameter of 7 mm, transverse tube pitch of 19 mm and longitudinal tube pitch of 12.5 mm are tested. The thermal fluid measurements are made using a psychometric calorimeter. The raw data are reduced to the desired heat transfer coefficient in terms of j-factor and friction factor of f for various frontal air velocities, fin pitches and number of tube rows.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.1
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• pp.8-14
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• 2005

The purposes of using cutting fluid during cutting have been cooling, lubricating, chip washing, and anti-corroding. However, the present manufacturing industry restricts the use of cutting fluid because cutting fluid contains poisonous substances which are harmful to the human body. Therefore dry cutting becomes an unavoidable assignment and a lot of researches have studied cutting methods without using cutting fluid. Because dry turning is a continuous work, tools life is reduced by continuous heat generation and surface gets rough due to reduced lubrication, so it is important to consider these situations. In this paper, the way of selecting the optimal machining condition by the minimum number of experiments and the effectiveness of using compressed air in high hardness materials through Taguchi method have been found. Dry cutting using compressed air showed better cutting characteristics than normal dry cutting with respect to by cutting force, tool wear, and surface roughness. Also, the optimal machining condition f3r dry cutting using compressed air could be selected through Taguchi method.