• The Korean Journal of Ecology
• /
• v.23 no.2
• /
• pp.131-134
• /
• 2000

Forest vegetation in Korea can be largely divided into warm temperate, cool temperate and frigid forest zone. The cool temperate forest zone of them occupies the largest part of the Korean peninsula and it is generally divided into three subdivisions such as northern, central and southern subzone. The Forestry Research Institute established three long-term ecological research sites at Kwangnung Experiment Forest in the central subzone of the cool temperate forest zone, at the Mt. Kyebangsan Forest in the northern subzone of the cool temperate forest zone. and at the Mt. Keumsan Forest in the warm temperate forest zone. The objectives of long-term ecological research in the Forestry Research Institute, Korea are to study long-term changes of the forest ecosystems in energy fluxes, water and nutrient cycling, forest stand structure, biological diversity, to quantify nutrient budgets and fluxes among forest ecosystem compartments and to integrate ecological data with a GIS - assisted model. To achieve the objectives, forest stand dynamics. environmental changes in soil properties, stream water quality, nutrient cycling, air pollution and biological diversity have been investigated and plant phonology as an indicator of climate change has been monitored in the LTER sites.

• 한국연소학회:학술대회논문집
• /
• 2003.05a
• /
• pp.13-19
• /
• 2003

As the environmental pollution becomes serious global problem, the regulation of emission exhausted from automobiles is strengthen. Therefore, it is very important to know how to reduce the NOx and PM simultaneously in diesel engines, which has lot of merits such as high thermal efficiency, low fuel consumption and durability. By this reason, the new concept called as Homogeneous Charge Compression Ignition(HCCI) engines are spotlighted because this concept reduced NOx and P.M. simultaneously. However, it is well known that HCCI engines increased HC and CO. Thus, the investigation of combustion characteristics which consists cool and hot flames for HCCI engines were needed to obtain the optimal combustion condition. In this study, combustion characteristics for direct inject type HCCI engine such as quantity of cool flame and hot flame, ignition timing and ignition delay were investigated to clarify the effects of these parameters on performance. The results revealed that diesel combustion showed the two-stage ignition of cool flame and hot flame, the rate of cool flame increase and hot flame decrease with increasing intake air temperature. On the other hand, the gasoline combustion is the single-stage ignition and ignition timing is near the TDC. In addition mixed fuel combustion showed different phenomenon, which depends on the ratio of gasoline component. Ignition timing of mixed fuel is retarded near the TDC and the ignition delay is increased according to ratio of gasoline.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.18 no.5
• /
• pp.115-123
• /
• 2010

Cool-down performance after soaking is important because it affects passenger's thermal comfort. The cooling capacity of HVAC system determines initial cool down performance in most cases, the performance is also affected by location, and shape of panel vent, indoor seat arrangement. Therefore, optimal indoor designs are required in developing a new car. In this paper, initial cool down performance is predicted by CFD(computational fluid dynamics) analysis. Experimental time-averaging temperature data are used as inlet boundary condition. For more reliable analysis, real vehicle model and human FE model are used in grid generation procedure. Thermal and aerodynamic characteristics on re-circulation cool vent mode are investigated using CFX 12.0. Thermal comfort represented by PMV(predicted mean vote) is evaluated using acquired numerical data. Temperature and velocity fields show that flow in passenger's compartment after soaking is considerably unstable at the view point of thermodynamics. Volume-averaged temperature is decreased exponentially during overall cool down process. However, temperature monitored at different 16 spots in CFX-Solver shows local variation in head, chest, knee, foot. The cooling speed at the head and chest nearby panel vent are relatively faster than at the knee and foot. Horizontal temperature contour shows asymmetric distribution because of the location of exhaust vent. By evaluating the passenger's thermal comfort, slowest cooling region is found at the driver's seat.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.12 no.1
• /
• pp.17-24
• /
• 2004

As the environmental pollution becomes serious global problem, the regulation of emission exhausted from automobiles is strengthened. Therefore, it is very important to know how to reduce the NOx and PM simultaneously in diesel engines, which has lot of merits such as high thermal efficiency, low fuel consumption and durability. By this reason, the new concept called as Homogeneous Charge Compression Ignition(HCCI) engines are spotlighted because this concept reduced NOx and P.M. simultaneously. However, it is well known that HCCI engines increased HC and CO. Thus, the investigation of combustion characteristics which consists cool and hot flames for HCCI engines were needed to obtain the optimal combustion condition. In this study, combustion characteristics for direct injection type HCCI engine such as quantity of cool flame and hot flame, ignition timing and ignition delay were investigated to clarify the effects of these parameters on performance. The results revealed that diesel combustion showed the two-stage ignition of cool flame and hot flame, the rate of cool flame increase and hot flame decrease with increasing intake air temperature. On the other hand, the gasoline combustion is the single-stage ignition and ignition timing is near the TDC. In addition mixed fuel combustion showed different phenomenon, which depends on the ratio of gasoline component. Ignition timing of mixed fuel is retarded near the TDC and the ignition delay is increased according to ratio of gasoline.

• Textile Coloration and Finishing
• /
• v.8 no.5
• /
• pp.7-16
• /
• 1996

The air-flow dyeing machine is a new type of dyeing machine. Which is an energy saving type to be able to dye the fabrics with the lowest liquor ratio and in shorter time. This machine is operated with an aerodynamic system rather than a hyd raulic system for traditional jet or overflow dyeing. An air-flow dyeing machine(Green-flow) by the use of aerodynamic technology was developed and compared with the Luft-roto machine made by Thies Company, Germany, in this study. Three samples were dyed with both machines under the same dyeing conditions and color fastness, dyeing levelness, drapability, and mechanical properties of these samples were compared. The results were as follows; Both machines have almost the same dyeability. The dyeability was good at liquor ratio of 1: 3.5 and the speed of 450yds/min. The order for drapability was Crepe de Chine > Cool Peach > Charmeuse. Except for the color fastness of sublimation being below class 4, most color fastness of samples dyed with Green-flow m/c were above class 4. The maximum speed was 510yds/min. for Crepe de Chine and the standard deviation of K/S value was lower for Charmeuse and Cool Peach when employed on the "Green-flow" machine and lower for Crepe de Chine when employed on the Luft-roto machine. Comparing with dyeing of the Green-flow machine and that of the Luft-roto machine, the RT of the Charmeuse was found to be higher with the Green-flow machine and thus the sample had an improved wrinkle recovery. LT and WT of Cool Peach were higher, and shear properties(G, 2HG, 2HGS) of Crepe de Chine were higher, both turning out as suitable for clothing. clothing.

• KIEAE Journal
• /
• v.8 no.5
• /
• pp.49-54
• /
• 2008

The experimental of temperature, humidity and velocity was taken from the underground pit which utilized the system of ground heat source quite similar to the cool-pit system. Also, through CFD analysis, one could review the effectiveness of analysis of future alternatives. Furthermore, the temperature range of mock up cool-pit system was analyzed by inputting the weather data of annual average soil temperature provided by KMA(Korea Meteorological Administration) into the fluid simulation of anticipated heat distribution. Firstly, the difference between the temperature of air exhaust of the pit or the temperature of air supply of the compressor room and the experimental data for the month of May from the CFD analysis came out to be $0.6^{\circ}C$ and $0.9^{\circ}C$ respectively with tolerance of 3.1% and 4.7%. Secondly, the difference between the temperature of air exhaust of the Pit or the temperature of air supply of the compressor room and the experimental data for the month of July from the CFD analysis came out to be $0.8^{\circ}C$ and $1.1^{\circ}C$ respectively with tolerance of 3.3% and 4.5%. Thirdly, for the month of May, the difference between the experimental data taken for the air exhaust of the Pit or the air supply of the compressor room and soil temperature provided by KMA for monthly and yearly average temperature of Jeonju region came out be $1.9^{\circ}C$ and $1.8^{\circ}C$ respectively with tolerance of 10.7% and 9.8%. Fourthly, for the month of July, the difference between the experimental data taken for the air exhaust of the Pit or the air supply of the compressor room and soil temperature provided by KMA for monthly and yearly average temperature of Jeonju region came out be $1.1^{\circ}C$ and $1.4^{\circ}C$ respectively with tolerance of 4.5% and 5.8%. The result of above experiments allowed us to establish CFD model set up as a verification tool that is based on experimental data collected within the Pit area. Also, one could confirm the possibility to apply weather data of soil temperature provided by KMA in order to anticipate proper value for CFD analysis.

• Journal of Environmental Science International
• /
• v.14 no.2
• /
• pp.215-220
• /
• 2005

Thermal neutrality is not enough to achieve thermal comfort. The temperature level can be the optimal, and still people may complain. This situation is often explained by the problem of local discomfort. Local discomfort can be caused by radiant asymmetry, local air velocities, too warm and too cold floor temperature and vertical temperature difference. This temperature difference may generate thermal discomfort due to different thermal sensation in different body parts. Therefore, thermal comfort can not be correctly evaluated without considering these differences. This study investigates thermal discomfort sensations of different body parts and its effect on overall thermal sensation and comfort in air-heating room. Experimental results of evaluating thermal discomfort at different body parts in an air-heating room showed that thermal sensation on the shoulder was significantly related to the overall thermal sensation and discomfort. Although it is known that cool-head, warm-foot condition is good for comfort living, cool temperature around the head generated discomfort.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.9 no.3
• /
• pp.45-51
• /
• 1985

The purpose of this study is to research into the thermal condition and the weight of clothes suitable for the officers engagged in light works in an air-conditioned room in summer. The Major findings are as follows: 1. Thermal conditions of the working environment are $24.5^{\circ}C$ (Dry bulb temp.), $68\%$ (Relative humidity) and 2.6m/sec (Air Velocity). 2. Total clothing weights are 416.6 g/$m^2$ (male) and 340.9 g/$m^2$ (female). Underwear weights are 96.8g/$m^2$ (male) and 85.1g/$m^2$ (female). The latter turned out to be statistically significant in Sexual difference. 3. Means of the thermal sensation are 3.0 (comfortable; male) 2.7 ('Slightly cool' -'Comfortable'; female) and the relationship between clothing weights and thermal sensation proves to be significantly correlated in the case of female. 4. $66.7\%$ of the women and $37.1\%$ of the men feel sensation of coldness at the body's specific area and $79.5\%$ of the women and $54.3\%$ of the men reveals air-conditioning disturbance. 5. As the thermal sensation is close to 'cool-cold', sensation of coldness or air conditioning disturbance are showed up more frequently which is reversely related with weight of under-wear. It is also proved that air conditioning disturbances are influenced by sexual difference in addition to sensation of coldness and thermal sensation. 6. According to the result of experiment, we can have the idea that at condition $X_1$, the drop of limbs' skin temp. is remarkable. At condition $X_2$ skin temp. for distal limbs and mean skin temp. are raised and the falling degree is similar. At condition $X_3$, mean skin temp. and distal skin temp. are remarkably raised, and the falling degree decreases and the beats of pulse rate increase and diastoric blood pressure is lowered.

• Science of Emotion and Sensibility
• /
• v.13 no.2
• /
• pp.359-370
• /
• 2010

The purpose of this study is to test the performance of the recommended summer dressing for office man through the analysis of skin temperature changes by air-conditioning temperature. We tested two clothing combinations; formal wear with necktie and casual shirts without necktie as for Cool mapsi. 4 male subjects sat to stabilize for thirty minutes after entering artificial-climate chamber with both temperature of $25^{\circ}C$, $27^{\circ}C$ and $50{\pm}10%$ R.H. And during 60 minute experiments of simulating office work, the subjective feelings including thermal, humidity and comfort sensation, skin temperature, clothing humidity and sweat amount were measured at the equal intervals. The result is that formal wear of $25^{\circ}C$ and Cool mapsi of $27^{\circ}C$ show good values such as low skin temperature, low clothing humidity and neutral thermal sensation. And Cool mapsi of $25^{\circ}C$ shows the risk of low rectal temperature for long and static energy level of office work. Formal wear of $27^{\circ}C$ shows high values of mean skin temperature, clothing humidity and thermal sensation. Second experiment was to find the ambient temperature when the subject wearing formal wear shows the skin temperature corresponding to which he shows on Cool mapsi of $27^{\circ}C$. The air-conditioning temperature on wearing formal wear has to be $2^{\circ}C$ lower to produce the corresponding skin temperature to which shows on wearing Cool mapsi of $27^{\circ}C$. Therefore it is possible to increase room temperature to $27^{\circ}C$, when wear Cool mapsi for summer office, for skin temperature and thermal sensation are produced the same.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
• /
• v.20 no.2
• /
• pp.125-133
• /
• 1991

This paper presents some design guidelines for using cold air/water distribution to cool commercial and industrial buildings. Cold air /water distribution systems provide primary air/water for space conditioning at nominal temperature between $3^{\circ}C$ and $10^{\circ}C$ ($4{\sim}5^{\circ}C$ might be recommendable for better selection). By using lower temperature primary air/water equipment could be downsized, means lower first costs, and often reduce annual energy costs up to 50% less than that of the conventional ($13^{\circ}C$) system. This concept takes full advantages of the $2{\sim}4^{\circ}C$ chilled water (brine) available with ice storate systems.