• Atmosphere
• /
• v.15 no.3
• /
• pp.179-186
• /
• 2005

Due to several difficulties, a number of Automatic Weather Systems (AWS) operated by Korea Meteorological Administration (KMA) are located on the rooftop so that the forming of standard observation environment to obtain the accuracy is needed. Therefore, the air temperature of AWSs on the synthetic lawn and the concrete of the rooftop is compared with the standard observation temperature. The hourly mean temperature is obtained by monthly and hourly mean value and the difference of temperature is calculated according to the location, the weather phenomenon, and cloud amount. The maximum and the minimum temperatures are compared by the conditions, such as cloud amount, the existence of precipitation or not. Consequently, the temperature on the synthetic lawn is higher than it on the concrete so that it is difficult to obtain same effect from ASOS, on the contrary the installation of AWS on the synthetic lawn seem to be inadequate due to heat or cold source of the building.

• Journal of Food Hygiene and Safety
• /
• v.12 no.4
• /
• pp.310-314
• /
• 1997

Antithiamin activities of BHA, BHT, PG and TBHQ of synthetic antioxidants on the effect of temperature and pH was determined by means of HPLC. The influence of synthetic antioxidants on the degration of thiamin was found to be dependent on temperature and pH. The degradation of thiamin was considerably more rapid at pH 7 than pH 4. The influence on the heat of synthetic antioxidants at pH 4 and 38* was extremely slight, but the degradation of thiamin at pH 7 was much more rapid at 60* than at 38*. After 24 hours of incubation both PG and TBHQ at pH 7 and 60* nearly completely destroyed thiamin. Tests of antithiamin activities showed that TBHQ, which was decomposed completely in 72 hours, was more effective than PG at pH 7 and 38* but BHA and BHT hardly had antithiamin activities which was evaluated under various reactions of pH and temperature. Thiamin degradation, at pH 7 and 6$0^{\circ}C$, was proportional to the concentration of PG. When the ratio of PG to thiamin was increased from 0.15:1 to 2:1, the degradation rate also increased. However, the change between ratio of 1:1 and 2:1 was negligible.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.9 no.4
• /
• pp.97-103
• /
• 2006

A synthetic infrared image can be effectively utilized in various fields such as the recognition and tracking of targets as long as its quality is good enough to reflect the real situations. One way to improve its quality is to use the reference atmosphere which best describes atmospheric properties of regional areas. The east asian reference atmosphere has been developed to represent atmospheric properties of the east asia including Korean peninsula. However, few research has been conducted to examine the effects of this east asian reference atmosphere on the modeling and simulation. In this regard, this paper analyzes the effects of the east asian reference atmosphere on a synthetic infrared image. The research compares the atmospheric transmittance, the surface temperature, and the radiance obtained by using the east asian reference atmosphere with those of the midlatitude reference atmosphere which has been widely applied in the east asia. The results show that the differences of the atmospheric transmittance, the surface temperature, and the radiance between the east asian reference atmosphere and the midlatitude reference atmosphere are significant especially during the daytime. Therefore, it is recommended to apply the east asian reference atmosphere for generating a synthetic infrared image with targets in the east asia.

• Carbon letters
• /
• v.5 no.3
• /
• pp.133-141
• /
• 2004

The synthetic behaviors of carbon nanotubes (CNTs) by Fe/MgO catalysts were investigated in 0~90 wt.% range of MgO mixture ratios by catalytic chemical vapor deposition (CCVD) process. The CNTs were synthesized with 40 minutes of synthetic time, and 923 K of synthetic temperature using 0.1 L/min of ethylene gas and 1.0 L/min of hydrogen gas as synthetic and carrier gas, respectively. As the increase of synthetic temperatures and times, the diameters of CNTs become thicker. The carbon yield showed in a parabolic curve as MgO content increased and the maximum carbon yield was obtained at 30 wt.% of MgO. There were no obvious changes in the diameters of CNTs respect to the change of MgO content. Fe/MgO CNTs showed good crystalinity by High Resolution Transmission Electron microscope (HR-TEM) analysis. The behaviors of Fe/MgO CNTs have a tendency of depending on synthetic time and temperature rather than MgO content.

• Elastomers and Composites
• /
• v.19 no.3
• /
• pp.163-177
• /
• 1984

The effect of curing temperature increase and sulfur amount added were studied with natural and synthetic rubbers. Also, the effects of TMTD, MBTS and mixture of zinc soaps of high molecular fatty acids added to natural rubber were investigated respectively. The experimental results showed that, in the case of the conventional curing ($145^{\circ}C$), natural rubber, compared with synthetic rubber, gave higher values in elongation, tensile strength, cure rate, and lower values in modulus change. But, at high temperature curing ($180^{\circ}C$), natural rubber showed faster reversion rate, and higher heat build-up compared to synthetic rubber, than in the conventional curing. Also, natural rubber produced at high temperature showed severe degradation in hardness and tensile strength before heat-aging as well as in hardness, modulus and tensile strength after heat-aging. Improved reversion effect was obtained with natural rubber either by blending mixture of zinc soaps of high molecular acids or by applying semi-efficient vulcanization system.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2003.11a
• /
• pp.545-548
• /
• 2003

The purpose of this study is measures vulcanization properties of matter by time of room temperature vulcanization synthetic rubber sheet and the evaluation adhesive properties tested by concrete surface moisture. Also, Its estimated reaction mechanism and adhesion performance between protection mortar and waterproofing layer. The results showed that vulcanization progressed in room temperature and adhesion intensity increased regardless of moisture condition.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.28 no.12
• /
• pp.1864-1870
• /
• 2004

A spot welded structures have an influence on a diverse climatic situation, for instance temperature, humidity and precipitation. In addition factors of environmental pollution such as acid rain, that courses corrosion, have the tendency to increase. But spot welded structures strength is affected by humidity and environment temperature. Therefore, it is important to evaluate effect of temperature and water immersion on strength properties of spot welded part. In this study, the strength distribution of spot welded plates is evaluated the environmental temperature of zinc coated steel plates. Test is conducted with welded part immersed in distilled and synthetic sea water. Specimens are immersed into water for 10, 100, 500 and 1000 hours to evaluate the offsets of water immersion time on tensile-shear strength under the conditions of -40, 0, 20 and 5$0^{\circ}C$. From this result, spot welded specimens with 5 mm clearance have lower tensile-shear strength in the distilled water or synthetic sea water than without clearance. And they have lower tensile-shear strength under -4$0^{\circ}C$ and over 5$0^{\circ}C$.

• Textile Coloration and Finishing
• /
• v.31 no.4
• /
• pp.258-267
• /
• 2019

Synthetic suede without PFCs(perfluorinated compounds) are followed by subsequent high temperature treatment. But migration fastness of synthetic suede may be reduced due to sublimation of disperse dyes that results from the high temperature treatment. Therefore, in this study, chitosan treatment was used to improve the migration fastness before polyurethane dipping process. Polyester fiber was treated with sodium hydroxide aqueous solution before chitosan processing. This samples treated with a chitosan concentration upto 0.5% were dyed and coated with PUD(polyurethane dispersion). The migration fastness was most improved at 0.35% application. This is presumably due to the fact that the chitosan may increase the dye-binding capability through intermolecular hydrogen bonding.

• Journal of the Korean Society of Combustion
• /
• v.16 no.4
• /
• pp.31-37
• /
• 2011

This paper presents both experimental and numerical investigation of the combustion characteristics of stretched premixed lift-off flames using synthetic gas($H_2$/CO) in an impinging burner. We used "Spin code" for numerical analysis. An ICCD camera was employed to measure flame location and flame thickness. The impinging surface temperature was affected by local strain rate K, equivalence ratio, and composition ratio of fuel. In spite of the difference of boundary conditions in experimental and numerical results, the tendencies of surface temperatures were agreed. From result of this work, we also found that flame location and flame thickness directly related to surface temperature are greatly affected by local strain rate K.

• Fire Science and Engineering
• /
• v.27 no.5
• /
• pp.19-25
• /
• 2013

The fire took place in the synthetic heat transfer fluid boiler. This study uses simulation to investigate the first, second and third passes and the temperature in the fire burner. The boiler's internal fluid is more or less unsteady due to the out of order inverter. As the operation continues, the flame's flow and speed are unsteady. The synthetic heat transfer fluid leak spouted about 120 kg/min in the form of vapor in the early period of the fire. The flame extended to the second and third passes. The highest temperature of the second and third pass is $1059^{\circ}C$ and $1007^{\circ}C$, respectively. The simulation shows that the temperature is $767^{\circ}C$ in the low part of the third pass. The synthetic heat transfer fluid spouted through the cracked part of the fire box in the first pass and accumulated on the turn table. The temperature rises to $183^{\circ}C$ in the low part of the burner. Therefore, it is expected that the temperature of the interior of the fire box is above $1200^{\circ}C$. The temperature of the burner rises to a maximum level several times in a short period. On account of that, several explosions occur in the fire burner.