• Journal of Bio-Environment Control
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• v.5 no.1
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• pp.34-42
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• 1996

This study was conducted to investigate the physical and optical properties of polypropylene and polyester thermal curtains, in which tensile strength, heat reservance and light transmission of two different materials were measured. The results from this study are as follows. 1. The tensile weight of different materials were ranged from 3.4kg to 13.4kg, according to the thickness of materials, but that no difference in the tensile strength was appeared between the two materials. The Elongation of polypropylene materials and the tensile weight and strength of polyester materials were greater than any other materials. 2. The light transmittances of two materials were ranged from 50.3% to 81.7 %, light transmittances in polypropylene were higher by 20-30%,than those in polyester. 3. The heat reservances of two materials were ranged from 18.2% to 41.2%, in which polypropylene showed better performance than polyester. 4. From the results of the test, the polypropylene thermal material was better in elongation, heat reservances and light transmittances, but polyester thermal material was better in tensile strength and light isolation than the other material.

• Journal of Bio-Environment Control
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• v.16 no.4
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• pp.284-290
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• 2007

Thermal insulation effectiveness of the aluminum insulator depending on the direction of its glossing face, number of layer and allocation position was investigated. Modules were assembled by the combination of the variables levels and experimented for the case of 100 W and 40 W heating in the modules. The temperatures in the modules with the aluminum insulator were higher than those of the modules with polyester curtains. For the modules with one layer aluminum insulator, the inside temperatures of the modules with the direction of the glossing face outward were higher than those of the modules of inward. For two layer of aluminum insulator, the directions of those glossing faces were recommended to be the same direction for higher thermal insulation effectiveness. For the modules without heating, the temperature difference between the modules were not significant. The black globe temperatures in the modules were changed with the similar tendencies with the dry bulb temperatures in the modules. Those of the black globes were higher than those of the dry bulb temperatures as a whole. It was more distinguished for the modules of inward direction.

• Journal of Korean Tunnelling and Underground Space Association
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• v.22 no.5
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• pp.563-574
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• 2020

Currently, road tunnels and railroad tunnels are building smoke control systems to emit toxic gases and smoke from fires. Among the various smoke control systems, the transverse smoke control system has the disadvantage that air supply or exhaust is performed on only half of the cross-section, rather than air supply or exhaust on the entire cross-section of the tunnel as air is supplied or exhausted by partitioning the wind path. Therefore, this study analyzed the effect of exhaustion through numerical analysis and scaled model tests on the zoning smoke control system, which improved the limitations of the transverse smoke control system. As a result of the scaled model test, the transverse ventilation system exhibited a 25.6% smoke control rate based on the state where no smoke was controled, and zoning smoke control system showed a smoke control rate of 40.8%. In addition, as a result of numerical analysis, it was found that transverse ventilation system did not control fire smoke spreading from the tunnel and continued to spread. On the other hand, zoning smoke control system was found to be smoke controled within a certain section due to the air curtain effect and the flue gas effect.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.12
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• pp.74-79
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• 2017

The fire extinguishing performance of hybrid nozzle systems is improved by injecting an extinguishing agent concentrically into the target site and, in this study, water mist is used as a water curtain to confine the droplets of the agent. In this study, we numerically investigated the effect of the foundation angle and injection pressure on the performance of a hybrid nozzle by evaluating the mean radius of the volume fractions of the agent and water mists. An experiment involving a water mist nozzle was carried out to validate the numerical method and then the droplet behaviors, e.g., stochastic collision, coalescence and breakup, were calculated with 2-way interaction Discrete Particle Modeling (DPM) in the steady state for the hybrid nozzle system. The mean radius of the water mists increased by about 40 %, whereas that of the agent decreased by about 21 %, when the injection pressure was increased from 30 bar to 60 bar. In addition, the mean radius of the agent increased by about 24 % as the foundation angle of the hybrid nozzle head increased from $30^{\circ}$ to $60^{\circ}$. As a result, it can be inferred that the injection angle and pressure are important factors for hybrid water mist designs.

• Korean Journal of Environmental Agriculture
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• v.27 no.4
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• pp.441-446
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• 2008

This study was conducted to determine the effect of heat stress on laying hen performance during summer. A total of 180 Hyline-brown layers, 98 days of age, were housed in a enclosed house. The daily maximum temperature in the house was ranged $26{\sim}36^{\circ}C$. The egg production was markedly fallen than other days when daily maximum temperature in the layer house became more than $33^{\circ}C$. As water intake and feed intake increased to $490\;mL\;bird^{-1}\;day^{-1}$ and $240\;g\;bird^{-1}\;day^{-1}$, the egg production soared. But it was hardly increased more than them. Based on these results, layer house roof should be amply insulated to improve the egg production of layers. If not insulated, the shade curtain should be installed above roof and cool water sprayed before and after 2 p.m. And layers should be provided cool drinking water of about $15^{\circ}C$ in the day time.

• The Journal of Engineering Geology
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• v.22 no.2
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• pp.195-205
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• 2012

We evaluated the results of pumping tests, the amount of groundwater used by Protected Cultivation with Water Curtain (PCWC), and monthly depth to water table (DTW) at the Wangjeon-ri area, Nonsan City, to elucidate the cause of a decrease in pumping rate during the winter PCWC season. The transmissivity and storage coefficient at eight sites where the major aquifer is alluvium, vary from 119.9 to $388.1m^2/d$ and $1.5{\times}10^{-4}$ to $5.5{\times}10^{-4}$, respectively. The pumping rate for PCWC during three months (Dec. to Feb.) averaged about $8,100m^3/d$ and the maximum water level in the area varied by about 10 m. Groundwater levels had fully recovered by August-five months after pumping for PCWC had ceased. These observations indicate that the pumping rate during the winter PCWC season was excessive compared with groundwater productivity in the area. Groundwater level in the central PCWC area varied from -3.0 to 4.38 m, exceeding the water level of the Nosung Stream for only three months (Aug. to Oct.). This result indicates that Nosung Stream recharges the area during the period from November to July. To solve the problem of reduced pumping rate during the winter PCWC season, it would be necessary to reduce the amount of groundwater used for PCWC or to develop an artificial recharge system using recycled groundwater.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.27 no.2
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• pp.79-93
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• 2015

Three-dimensional structures of large ocean rings in the Gulf Stream region are investigated using the HYbrid Coordinate Ocean Model (HYCOM). Numerically simulated flow structures around four selected cyclonic and anticyclonic rings are compared with two different horizontal resolutions: $1/12^{\circ}$ and $1/48^{\circ}$. The vertical distributions of Lagrangian Coherent Structures (LCSs) are analyzed using Finite Size Lyapunov Exponent (FSLE) and Okubo-Weiss parameters (OW). Curtain-shaped FSLE ridges are found in all four rings with extensions of surface ridges throughout the water columns, indicating that horizontal stirring is dominant over vertical motions. Near the high-resolution rings, many small-scale flow structures with size O(1~10) km are observed while these features are rarely found near the low-resolution rings. These small-scale structures affect the flow pattern around the rings as flow particles move more randomly in the high-resolution models. The dispersion rates are also affected by these small-scale structures as the relative horizontal dispersion coefficients are larger for the high-resolution models. The absolute vertical dispersion rates are, however, lower for the high-resolution models, because the particles tend to move along inclined eddy orbits when the resolution is low and this increases the magnitude of absolute vertical dispersion. Since relative vertical dispersion can reduce this effect from the orbital trajectories of particles, it gives a more reasonable magnitude range than absolute dispersion, and so is recommended in estimating vertical dispersion rates.

• Korean Journal of Food Science and Technology
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• v.52 no.3
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• pp.284-289
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• 2020

The cultivars of wine grapes 'Doonuri', 'Narsha', 'Cabernet Sauvignon', and 'Merlot' were cultivated in Modified-T (MT), Modified-T Cane pruning (MTC), and Geneva Double Curtain (GDC) trellises, and the changes in vine growth, fruit and wine characteristics were compared for two years (2018 and 2019). With respect to the vine growth characteristics, the wine grape cultivars cultivated in the GDC trellis were significantly inferior to those cultivated in the MT or MTC trellises. The grape yields of the cultivars cultivated in GDC trellise increased by 1.5 to 2 times cultivated in the GDC trellises compared to those cultivated in the other trellis, however, the fruit characteristics (total soluble solids, titratable acidity, and berry weight) did not differ among the differently cultivated groups. Moreover, the anthocyanin content and red color of the wine were significantly enriched in all red wine grape cultivars cultivated in the GDC trellises.

• Journal of the Korean Home Economics Association
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• v.20 no.1
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• pp.65-77
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• 1982

The intent of this study was to focus attention on the relationship between curtain fabrics and consumer perceptions towards curtains and draperies. This study consisted of the laboratory test for thermal transmittance of selected fabrics and the exploratory survey for consumer perceptions towards curtains and draperies. The objectives of the laboratory test were to measure fabric's thermal transmittance, thickness, and count which affect to the effect in heat controlling. Selected 23 fabrics were tested at Korean Yarn and Fabrics Testing Inspection Institute. The objectives of the exploratory survey were to determine sociodemographic factors; the stage of family life cycle, the economics status, and homemaker's level of education, and physical factors; the type of houses, the direction of windows, and the type of windows, affect consumer perceptions toward curtains and draperies. Questionaires were administered to 489 homemakers selected by a stratified propotional sampling plan, in Seoul in October, 1981. Data from responses were analyzed by T-test(Analysis of Varience) and Partial Correlation. The major findings are as follows; 1. The results of the laboratory test 1) The fabrics used for draperies had higher effect in heat controlling than the fabrics used for glass curtains. 2) It did not show much differences among the fibers in heat controlling. The thicker fibers, however, had the higher effect in heat controlling among same fibers. 3) The fabrics which had high level of effect I heat controlling were corduroy, flax, rayon, nylon, acetate, thick polyester, and thick polyacrylic. The fabrics which had midium level of affect in heat controlling were velveteen, velvet, and thin polyester. The fabrics which had low level of effect in heat controlling were cotton, silk, and thin polyarcylic. 4) The draperies with lining showed 2∼5 times more effective in heat controlling than the draperies without lining. 2. The results of the exploratory survey Consumer perceptions towards curtains and draperies consisted of functional, financial, and aesthetic perception. 1) Factor affecting functional perception towards curtains and draperies was the stage of family life cycle. Families in the contracting stage considered function of curtains and draperies significantly better than those in others stages. 2) Factors affecting financial perception towards curtains and draperies were the economic status, homemaker's level of education, the direction of windows, and the type of windows. However the correlation between the factors and financial perception was too low to explain the significance of tendency. 3) There was not any factors affecting aesthetic perception towards curtains and draperies.

• Journal of the Korean Solar Energy Society
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• v.32 no.4
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• pp.24-33
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• 2012

Recently, finishing materials at spandrel area, a part of curtain-wall system, are gradually forced to improve thermal insulation performance in order to enhance the building energy efficiency. Also, Building Integrated Photovoltaics(BIPV) systems have been installed in the exterior side of the spandrel area, which is generally composed of windows. Those BIPVs aim to achieve high building energy efficiency and supply the electricity to building. However, if transparent BIPV module is combined with high insulated spandrel, it would reduce the PV efficiency for two major reasons. First, temperature in the air space, located between window layer and finishing layer of the spandrel area, can significantly increase by solar heat gain, because the space has a few air density relative to other spaces in building. Secondly, PV has a characteristics of decreased Voltage(Voc and Vmp) with the increased temperature on the PV cell. For these reasons, this research analyzed a direct interrelation between PV Cell temperature and electricity generation performance under different insulation conditions in the spandrel area. The different insulation conditions under consideration are 1) high insulated spandrel(HIS) 2) low insulated spandrel(LIS) 3) PV stand alone on the ground(SAG). As a result, in case of 1) HIS, PV temperature was increased and thus electricity generation efficiency was decreased more than other cases. To be specific, each cases' maximum temperature indicated that 1) HIS is $83.8^{\circ}C$, 2) LIS is $74.2^{\circ}C$, and 3) SAG is $66.3^{\circ}C$. Also, each cases yield electricity generation like that 1) HIS is 913.3kWh/kWp, 2) LIS is 942.8kWh/kWp, and 3) SAG is 981.3kWh/kWp. These result showed that it is needed for us to seek to the way how the PV Cell temperature would be decreased.