• Asian-Australasian Journal of Animal Sciences
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• v.7 no.1
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• pp.97-101
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• 1994

Two experiments were conducted to study the effect of ambient temperature and nicarbazin on SCWL adult roosters. In Experiment 1, the effects of nicarbazin supplementation (125 ppm) on the water metabolism, blood acid-base balance; and rectal temperature of 16 birds in normal ($21^{\circ}C$) and hot ($35-36^{\circ}C$) temperature were investigated. In Experiment 2, the evaporative water loss and $CO_2$ exhalation from 8 birds were measured individually with an open-circuit gravimetric respiration apparatus in normal ($21^{\circ}C$) and hot ($33.5-34^{\circ}C$) temperature. The amount of water intake and evaporative water loss increased in birds under heat stress (HS). Nicarbazin exacerbated these effect in hot temperature. Also, nicarbazin decreased the blood $pCO_2$ and increased pH of HS birds. The rectal temperature of birds increased in hot temperature, and nicarbazin worsened this effect. The evaporative water loss, measured directly with respiration apparatus (Experiment 2), was increased in hot temperature. HS decreased the amount of $CO_2$ exhalation. Nicarbazin did not exert ant effect on either of these measurements, probably due to the limited duration (2 h) of the trial. The decrease in $CO_2$ exhalation by HS birds could be explained by reduced metabolic rate, which helps homeothermy of birds in hot temperature.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.2
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• pp.121-127
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• 2004

This paper describes conceptual development and idea-verification of a sub-miniature portable cooler which dose not necessitate any pre-cooling nor any external energy supply. The basic principle of the cooling mechanism is the vaporization of water and sub-sequent cooling due to the evaporative latent heat loss. In this work, the vaporization of the water is stimulated by desiccant material to improve the cooling effect. The evaporative cooling caused by the desiccant is modeled and analyzed considering the sorption characteristics of the desiccant. In addition, the portable cooler is fabricated in the shape of a thin pad, and its cooling characteristics are tested and compared with the analytic results.

• Fashion & Textile Research Journal
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• v.11 no.6
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• pp.947-952
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• 2009

The purpose of this study is to analyze skin wettedness($w$) used as the rate index of thermal comfort, and to evaluate the wear comfort of outdoorwear. Skin wettedness is widely used to express the degree of thermal comfort. If skin wettedness exceeds a certain threshold, the body feels damp and discomfort. An experiment which consisted of rest(30 min), exercise(30 min) and recovery(20 min) periods was administered in a climate chamber with 10 healthy male participants. Two kinds of outdoorwears made of 100% cotton fabrics (Control) and specially engineered fabrics having feature of quick sweat absorbency and high speed drying fabric (Functional) were evaluated in the experiment. The condition of climate chamber was controlled according to the thermal insulation of 4 kinds of experimental ensembles(E1~E4). Total sweat loss, sweat loss absorbed into clothing and skin temperature were measured. Skin wettedness was calculated from the ratio of evaporative rate to the maximal evaporative capacity. Skin wettedness of 'Functional' was lower than 'Control' in the 3 kinds of ensembles(E1, E2, E4) because the materials of 'Functional' were composed of quick sweat absorbency and high speed drying fabrics, water vapour permeability and waterproof fabrics.

• Asian-Australasian Journal of Animal Sciences
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• v.10 no.3
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• pp.318-323
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• 1997

In order to assess the effect of solar exposure on pulmonary functions and evaporative losses from skin and pulmonary surfaces, in six healthy Sahiwal (S) and six Sahiwal ${\times}$ Holstein ($S{\times}H$) cattle were exposed to direct sun during summer. Breed differences were observed during exposure. Increase in sweating rate was higher in crossbreds (222%) than in Sahiwal (125%). Pre-exposure (ambient temperature, $32.6{\pm}0.85^\circ}C$, solar radiation, $0.9cal\;cm^{-2}min^{-1}$) evaporative loss from skin accounted for about 90% of the losses and remaining losses were contributed by pulmonary surfaces in Sahiwal. The contribution of evaporation through skin increased to 92% (ambient temperature $39.4{\pm}0.68^\circ}C$, solar radiation, $1.35cal\;cm^{-2}min^{-1}$). In crossbreds 80% of the evaporative losses were through skin before exposure which increased to 87% after exposure to solar radiations. Rectal temperature increase was higher in crossbreds ($1.5^{\circ}C$) than in Sahiwal ($0.8^{\circ}C$). With the increase in pulmonary evaporative losses, respiratory frequency increased to 2 fold in Sahiwal and pulmonary ventilation increased 1.6 times the resting value in Sahiwal due to solar exposure. In $S{\times}H$ crossbreds the respiratory frequency increased 3.5 times and pulmonary ventilation increased only to 1.8 times due to decrease in tidal volume. There was about 2 fold increase in alveolar ventilation in both the breeds, the increase in dead space ventilation was more in crossbreds than in Sahiwal. Behavioral symptoms exhibited by animals after exposure were profuse salivation, open mouth panting, tongue protrusion and general restlessness.

• Korean Journal of Poultry Science
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• v.22 no.3
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• pp.133-144
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• 1995

One metabolism trial(Experiment I) and another respiration trial(Experiment II) were conducted to investigate the effects of dietary fiber supplementation(20% wheat bran) on the water balance, blood acid-base balance, body temperature, and metabolic rate of heat-stressed adult roosters. In Experiment I, twenty 20-wk-old SCWL roosters(BW 1.6 kg) were randomly alloted to 4 treatments with 5 birds per treatment and one per replicate. The 4 treatments were consisted of two temperature(21~22˚C vs. 34~35˚C) and two dietary fiber treatment(0% and 20% wheat bran), making Experiment I a 2x2 factorial. After 4 d of preliminary period, birds we subjected to 3-d collection period. Sixteen 20-wk-old SCWL roosters(BW 1.6 kg) were employed Experiment H, with two temperature(21~22˚C vs. 34~35˚C) and two wheat bran levels(0% and 20%). Brids were housed in individual metabolism cages under normal temperature(21~22˚C), at fed one of the experimental diet. After 4 d of preliminary period, a respiration trial with open-circuit gravimetric respiratory apparatus was carried out for each bird for 6 h, one by one, normal(20~21˚C) and hot(34~35˚C) temperatures. The ANOVA test and comparisons among treatment means were done at 5% probability level for both experiments. Results obtained from Experiment I and, II were summarized as follows, 1.The amounts of DM intake and excretion were significantly(P<.05) decreased by heat stress. The DM intake was not affected by the addition of 20% wheat bran, however, the amount of DM excretion was significantly increased by the high fiber diet. Thus, the DM metabolizability decreased significantly by the addition of 20% wheat bran. 2. The heat-stressed roosters increased the water intake and excreta moisture content significantly. Although not significant, the water intake tended to increase in roosters fed the 20% wheat bran diet. 3. The amounts of total water input and evaporative water loss were increased significantly by heat stress, and the addition of 20% wheat bran did not exert any influence on the total water input and evaporative water loss. However, roosters fed the 20% wheat bran diet increased the excreta water output significantly. 4. Neither the heat stress nor the dietary fiber did affect the blood pH, pCO2, and HCO$_3$- significantly. 5. The body temperature increased significantly by the heat stress. However, the high fiber deit failed to decrease the body temperature. 6. The heat-stressed roosters decreased the 02 consumption and C0$_2$ production, and increased the evaporative water loss significantly. However, the high fiber diet did not exert any infulence in this regard. It appears that the beneficial effect, if any, of high fibrous diet during heat stress episode may be due to the increased heat loss through the enhanced excreta water.

• Horticultural Science & Technology
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• v.18 no.6
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• pp.839-844
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• 2000

In developing of soil wetting agents using the mixture of polyoxyethylene octylphenyl ether [$C_8H_{17}O$ $(C_2H_4O)_{10}H$, POE] and polyoxyethylene+polypropyleneoxide tridecylether (1:1, w/w, CM-1), the effect of base carriers such as zeolite and vermiculite on changes of concentration of POE and on initial wetting of peat-vermiculite media were determined. The concentration of POE in the treatment of zeolite was higher than that of vermiculite. The treatments of POE+CM-1 with zeolite or vermiculite as carrier were effective in initial water retention of root media having about 510 mL of water per pot, where those of AquaGro and control had 490 mL and 400 mL of water per pot, respectively. In the evaporative water loss, the treatment of zeolite and AquaGro were faster than those of control and vermiculite. The treatment of AquaGro had faster water movement in root media than those of POE+CM-1 regardless of carriers and same trends were observed in the volume of water infiltrating into root media. Also, increasing the amount of POE+CM-1 resulted in increased water retention capacity, evaporative water loss, water movement in root media and amount of water infiltrating into root media.

• Korean Journal of Poultry Science
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• v.20 no.3
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• pp.151-159
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• 1993

An experiment was conducted to study the effects of nicarbazin supplementation (125 ppm) on the water balance, blood acid-base balance, and rectal temperature of 16 SCWL adult roosters in normal($21^{\circ}C$) and hot(35~$36^{\circ}C$) temperatures. There were 4 d of preliminary period, followed by 2 d of sampling and data collection period for each temperature treatment. The amounts of DM intake and excretion were not affected by heat stress but by rucarbazln supplementation. The DM metabolizability of diets, however, was decreased by nicarbazin. The amounts of water intake and evaporative water loss were increased in heat stressed birds. Nicarbazin increased further the amounts of water intake and evaporative water loss in hot temperature. Nicarbazin also decreased the blood p$CO_2$ and increased blood pH of heat stressed birds. The rectal temperature of the bird was increased in hot temperature, and the nicarbazin supplementation worsened this effect. Results indicate that heat stress raises the body temperature of the chicken. In order to suppress the rise of body temperature, the birds enhance the evaporative water loss through panting. The nicarbazin supplementation to heat stressed birds, however, increases the body temperature to such an extent that panting alone may not be able to return the body temperature back to normal.

• Horticultural Science & Technology
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• v.18 no.5
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• pp.612-620
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• 2000

In developing soil wetting agent using polyoxyethylene octylphenyl ether [$C_8H_{17}O(C_2H_4O)_{10}H$, POE], the effect of mixtures of POE and polyoxyethylene+polypropyleneoxide tridecylether (1:1, w/w, CM-1), polyoxyethylene+polypropyleneoxide tridecylether+propyleneglycol monomethylether (1:1:2, w/w/w, CM-2) or glycerin+ditridecyl phthalate (1:1, w/w, CM-3) on changes of concentration of POE, initial wetting, evaporative water loss, water infiltration, and changes of physical properties in root media were determined. The mixtures of POE and CM-1, 2, or 3 with zeolite or vermiculite as carrier had high concentrations of POE in root media during 6 elution times, but those after 6 times decreased rapidly indicating unstable elution of POE. The commercial AquaGro was more effective than the mixtures of POE+CM-1, 2, or 3 in water retention during 18 hours. Root media incorporated with POE+CM-2 held more water than any other treatments at 84 hours after watering, but the differences among treatments except control were not significant. In the treatments with zeolite as a carrier, POE+CM-3 had the greatest evaporative water loss followed by POE+CM-2, AquaGro, control, and POE+CM-2. In the treatments with vermiculite as a carrier, POE+CM-1 had the highest evaporative water loss followed by POE+CM-3, AquaGro, control, and POE+CM-2. In the effect of mixtures with zeolite as a carrier on infiltration of water into root media, the treatment of POE+CM-1 had the highest amount of water infiltrated followed by POE+CM-3, AquaGro, POE+CM-2, and control. In the effect of mixtures with vermiculite as a carrier on infiltration of water into root media, the treatment of POE+CM-3 had the highest amount of water infiltrated followed by AquaGro, POE+CM-1, POE+CM-2, and control.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.8
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• pp.316-324
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• 2016

This study investigated a compact regenerative evaporative cooler (REC). To achieve practical applications of an REC, it is very important to consider the compactness as well as the cooling performance. Therefore, a prototype of the REC was designed and fabricated to improve the compactness by reducing the length through the insertion of fins in both the dry and wet channels. The REC prototype was tested in terms of performance evaluation under various operating conditions. An analytical model was also developed to analyze the effects of the axial conduction through the solid body of the REC, the wetness of the surface in the wet channel, and the thermal capacity of the evaporation water flow. The model was validated by comparing the results of a simulation with experimental data. The numerical simulation was based on the model to analyze the performance of the REC and to suggest methods to improve the cooling performance of the REC. Finally, the performance of the present REC was compared to that obtained in previous experimental studies. The results showed that the REC prototype in the present study is the most compact and achieves the highest cooling performance.

• Journal of Environmental Impact Assessment
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• v.22 no.4
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• pp.329-343
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• 2013

According to previous studies, the increased air temperature can lead to change of thermal stratification structure of lakes and reservoirs. The changed thermal stratification may result in alteration of materials and energy flow. The objective of this study was to predict the effect of climate change on the water temperature and stratification structure of Daecheong Reservoir, located in Geum River basin of Korea, using a three-dimensional(3D) hydrodynamic model(ELCOM). A long-term(100 years) weather data set provided by the National Institute of Meteorological Research(NIMR) was used for forcing the 3D model. The model was applied to two different hydrological conditions, dry year(2001) and normal year(2004). It means that the effect of air temperature increase was only considered. Simulation results showed that the surface water temperature of the reservoir tend to increase in the future, and the establishment of thermal stratification can occur earlier and prolonged longer. As a result of heat flux analysis, the evaporative heat loss can increase in the future than now and before. However, the convective heat loss and net long wave radiation from water surface decreased due to increased air temperature.