• Journal of the Korean Society of Industry Convergence
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• v.26 no.1
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• pp.183-191
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• 2023

This study was conducted experimentally to investigate the surface temperature of the heat sink, the air temperature in the flow channel and the sample temperature by changing the channel number of channel type heat sink and the air flow rate when heating and cooling the bio sample. The target temperature of the sample was 15℃ or less as the minimum value and 82℃ or more as the maximum value. In this study, the channel number of the heat sink(N = 1, 2, 4, 5, 10) and the air flow rate(Q=25, 42, 54m³/min) were varied. The bio sample was replaced with water, and the volume of water is 4mL. The size of the heat sink is 80x73x150mm and the material is aluminum. When cooling the sample, the surface temperature, the air temperature and the sample temperature were highly dependent on the number of channels and the flow rate. However, when the sample is heated, the surface temperature, air temperature and sample temperature do not depend on the number of channels and the flow rate. It was found that the conditions for satisfying the minimum temperature of 15℃ or less when cooling the sample were the number of channels N≥5 and the flow rate Q≥42m³/min. When heating the sample, the conditions to satisfy the maximum temperature of 82℃ or more are the number of channels N≤5 and the air flow rate Q≤42m³/min.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.1
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• pp.10-17
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• 1999

The present work presents condensation heat transfer and pressure drop data for the flow of R-12 in flat extruded aluminum tubes with small hydraulic diameters. The tube outside dimensions are $18mm(width){\times}1.7mm(height)$. Three types of internal geometry with the same outside dimensions are tested : sample 1 (7 tube holes), sample 2 (13 tube holes) and sample 3 (7 tube holes, micro-fin). The overall heat transfer coefficient is obtained for air-to-refrigerant heat transfer, and the Wilson plot method is used to determine the heat transfer coefficient for refrigerant flow. The sample 2 and sample 3 show significantly higher performance than sample 1. The heat transfer rates for the sample 2 and sample 3 are 9% and 12% higher, respectively, than sample 1. The friction factors for the sample 2 and sample 3 are 11.9% and 2.4% higher, respectively, than sample 1.

• Food Science and Biotechnology
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• v.14 no.5
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• pp.661-666
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• 2005

The specific objectives of this study were to dry yam chips using microwave vacuum drying, freeze drying and hot air drying, then to coat the dried yam chips with ascorbic acid cocrystallized sucrose, and finally to compare the quality of yam chip snack foods with respect to drying and coating characteristics. The microwave vacuum dried sample showed the highest drying rates and much less surface damage than the hot air dried one did. The shape and color of the microwave vacuum dried/coated sample were allocated between those of the freeze dried/coated sample and the hot air dried/coated sample. The freeze dried/coated sample scored excessively low in organoleptic hardness and chewiness to be suitable as a snack. The hot air dried/coated sample was too deep in color, wrinkled, excessively high in organoleptic hardness and chewiness, and excessively low in mouthfeeling. Therefore, the microwave vacuum dried/coated sample presented the best overall attributes as a snack, with respect to organoleptic characteristics, shape, color, and drying rates.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.9
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• pp.1353-1358
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• 2010

Improvement in the utilization of grape pomace, antioxidant activities and antioxidant compounds of grape pomace was analyzed to clarify the influence of drying method such as $80^{\circ}C$ hot air and freeze ($-70^{\circ}C$) drying process. For proximate composition, crude protein and fat contents of hot air drying sample were higher than freeze drying sample. The lightness and redness values of freeze drying sample were higher than hot air drying sample, but yellowness of hot air drying sample was higher. The contents of total polyphenols and anthocyanins were higher in freeze drying sample. DPPH radical scavenging activity and ABTS scavenging activity of freeze drying sample were higher than hot air drying sample. The reducing power and FRAP value of hot air drying sample was higher than freeze drying sample. The result indicated that freeze drying method is slightly better than hot air drying method for antioxidant compounds and antioxidant activity.

• Journal of the Korean Institute of Landscape Architecture
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• v.34 no.2 s.115
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• pp.36-43
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• 2006

This study was carried out to determine the ways in which drying improves and develops dredged soils which exist widely in the lowlands of Korea. Before drying there were large variations in the fundamental physico-chemical properties of dredged soils collected from different places. In the sample soils, saturated hydraulic conductivity decreased gradually with an increase in bulk density with the exception that in air-dried soils a reverse trend was observed. Also in the sample soils, the sedimentation volume and the consistency limits decreased gradually with the decrease in soil water content after the air-drying treatment. The porosity of the sample soils decreased from $0.67{\sim}0.87m^3/m^3\;to\;0.58{\sim}0.66m^3/m^3$ and the liquid-phase range decreased from $0.41{\sim}0.83m^3/m^3\;to\;0.29{\sim}0.71m^3/m^3$. The solid-phase range of sample soils increased $0.13{\sim}0.33m^3/m^3\;to\;0.24{\sim}0.37m^3/m^3$ same as above with air-drying treatment. In conclusion the air-drying treatment caused an irreversible effect on some physical properties. Accordingly, these facts indicate that the effects of air-drying treatment on these properties are considered to be resulted from irreversible changes in the structural status of the sample soils.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.202-208
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• 2008

The objectives of this study are to collect the population of each cooling system for gas and electric driven systems, and propose sample design for five cooling systems; ice storage systems, system air-conditioning system, turbo system as electric driven cooling systems, and absorption system and Gas driven Heat Pump (GHP) system as gas driven cooling systems. The sample design are carried out based on types of business, capacity, installation region and year. This study proposes criterion of the sample design for cooling systems for each energy source.

• Journal of Powder Materials
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• v.13 no.6 s.59
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• pp.401-407
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• 2006

Effects of oxygen deficiency on the room temperature ferromagnetism in Fe-doped reduced $TiO_2$ have been investigated by comparing the air-annealed $Ti_{0.97}Fe_{0.03}O_2$ compound with secondly post-annealed one in vacuum ambience. The air-annealed sample showed a paramagnetic behavior at room temperature. However, when the sample was further annealed in vacuum, a strongly enhanced ferromagnetic behavior was observed at same temperature. $M{\"{o}}ssbauer$ spectra of air-annealed sample at 295K showed a single doublet of $Fe^{3+}$, suggesting that the Fe ions are paramagnetic. On the other hand, the absorption spectra after vacuum-annealing exhibited two doublets, in which one is the same component with air-annealed sample and the other is new doublet corresponding to $Fe^{2+}$ state. This result suggests that the occurrence of ferromagnetism in reduced sample may be interpreted as the contribution of unquenched orbital moment of $Fe^{2+}$ ions.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.6
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• pp.958-964
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• 1994

To study on the superconducting properties with cooling conditions, silver-sheathed Bi-Pb-Sr-Ca-Cu-O wires fabricated by the powder-in-tube method. The wires cooled down in the furnace, air and liquid NS12T after sintering at 840$^{\circ}C$ Critical current density of sample cooled in the furnace is 5.1${\times}$10S03TA/cmS02T and sample cooled in the air is 40A/cmS02T at 77K, zero magnetic field. The latter is very low critical current density of Bi system. 2223 high-Tc superconducting phase of sample cooled in the air was distroyed. Properties of sample cooled down in the liquid nitrogen is the same as cooled in the furnace.

• Elastomers and Composites
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• v.48 no.3
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• pp.221-224
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• 2013

In this study, VOC analysis method of vehicle interior materials and parts treated to visible-light responsive photocatalyst was tested by sample bag filled with air instead of nitrogen. As a result, when analyzed VOC of vehicle interior materials and parts, sample bag filled with the nitrogen was not confirmed of effect reducing VOCs and formaldehyde. However, VOCs and formaldehyde of sample bag that was filled with air instead of nitrogen, decreased significantly. Reaction effect for visible light-responsive photocatalyst was confirmed that sample bag of vehicle interior materials and parts should be filled with air instead of nitrogen.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.33 no.4
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• pp.455-463
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• 2023

Objectives: The aim of this study was to develop an air sampling and analytical method for estimating worker exposure to linear carbonate solvents and to evaluate the method. Methods: The target substances were three linear carbonates: DMC, DEC, EMC. GC/FID was used for sample analysis. Laboratory experiments were conducted to determine desorption solvents and sample capacity, and to evaluate storage stability, accuracy, and precision. Results: Coconut Shell Charcoal (CSC, 100/50 mg) was used as the air sampling media, and a desorption solvent of 5% methanol/95% dichloromethane was selected. Recommended sampling capacities were 1~11 ℓ for DMC, 1~18 ℓ for DEC, and 1~24 ℓ for EMC. The stability of three linear carbonates was demonstrated over 30 days in a refrigerator (4℃). Detection limits were determined as follows: DMC 0.26 ㎍/sample, DEC 0.24 ㎍/sample, and EMC 0.25 ㎍/sample. The total coefficient of variation was calculated as DMC 0.064, DEC 0.079, and EMC 0.07. Conclusions: This sampling and analysis method is suitable for estimating personal exposure to linear carbonates in the workplace.