• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.7
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• pp.462-469
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• 2008

A regenerative evaporative cooler has been fabricated and tested for the evaluation of cooling performance. The regenerative evaporative cooler is a kind of indirect evaporative cooler comprised of multiple pairs of dry and wet channels. The air flowing through the dry channels is cooled without any change in the humidity and at the outlet of the dry channel a part of air is redirected to the wet channel where the evaporative cooling takes place. The regenerative evaporative cooler fabricated in this study consists of the multiple pairs of finned channels in counterflow arrangement. The fins and heat transfer plates were made of aluminum and brazed for good thermal connection. Thin porous layer coating was applied to the internal surface of the wet channel to improve surface wettability. The regenerative evaporative cooler was placed in a climate chamber and tested at various operation condition. The cooling performance is found greatly influenced by the evaporation water flow rate. To improve the cooling performance, the evaporation water flow rate needs to be minimized as far as the even distribution of the evaporation water is secured. At the inlet condition of $32^{\circ}C$ and 50%RH, the outlet temperature was measured at $22^{\circ}C$ which is well below the inlet wet-bulb temperature of $23.7^{\circ}C$.

• Korean Journal of Pharmacognosy
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• v.36 no.3 s.142
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• pp.209-219
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• 2005

In this study, we carried out the preparing standardization and regulation of processed Glycyrrhizae Radix (PGR) which have been widely used in oriental medicines. Glycyrrhizae Radix(GR) have been generally prepared by the stir-frying, or mix-frying with honey for the purpose of decreasing sweetness and augmenting vitality. Firstly, we tried to standardize PGR prepared by the stir-frying. We purchased 14 kinds of PGR and non-processed GR(NPGR) at oriental physician's offices and oriental pharmacies on a nation scale, respectively. The amounts of dry on loss, water extract, diluted ethanol extract, ether extract, total ash, acid insoluble ash, glycyrrhizin(GL), glycyrrhetic acid(GA) and liquiritin(LQ) of them were examined. The amounts of dry on loss, GL and LQ in commercial PGRs showed remarkable decrease, while GA showed increased as compared with NPGR. In order to standardize preparing method of PGR, the effect of heating time on physico-chemical parameters and biological activities were examined. Physico-chemical parameters such as dry on loss, extract amount, GL and LQ contents in PGRs showed decrease, however, GA was increased with heating time as compared with NPGR. Also, GA, obtained from heat-treated GR, was found as an artifact in PGRs. PGR was more effective than NPGA in vitro test of DPPH scavenging effect and TBA-Rs reducing effect. PGR and NPGR showed potent hepatoprotective effect on $CCl_4-intoxicated$ rats. Especially, PGR prepared by 80 min of heating was the most effective. Considering these results, the optimal condition for PGR preparation was $150^{\circ}C$ for 80 min.

• Korean Journal of Food Science and Technology
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• v.12 no.1
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• pp.24-33
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• 1980

Trypsin inhibitor and hemagglutinating activities of some minor beans produced in Korea were determined in comparison with those of soybean and the effects of heat treatment on the activities were studied. The results are summarized as follows 1. The trypsin inhibitor activity (% [TU] inhibited/mg) of soybean, red bean, kidney bean, and mung bean were 79.9, 46.4, 43.2 and 17.7, respectively, on the dry weight basis and were 194, 222, 170 and 75, respectively, on the protein basis. 2. Heat destruction by boiling or autoclaving of trypsin inhibitor activity of red bean, mung bean, kidney bean, and soybean were $85{\sim}87,\;87{\sim}94,\;76{\sim}79\;and\;67{\sim}72\;%$, respectively. No significant difference was, however, observed in the effect between the two heating methods. 3. The hemagglutinating activity (unit/g) of kidney bean, soybean, mung bean and red bean were 48,300, 18,000, 136 and non-detectable, respectively, on the dry weight basis and were 190,600, 43,700, 581 and non-detectable, respectively, on the protein basis. Heat treatment destructed the hemagglutinating activity in all three beans.

• Korean Journal of Soil Science and Fertilizer
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• v.23 no.2
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• pp.94-99
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• 1990

A field experiment was conducted to study seasonal evapotranspiration above soybean canopy and its relationship with dry matter production by the Bowen ratio-energy balance method. The soybean "Paldalkong" was sown with the space of $47{\times}10cm$ at Suwon on May 27, 1988. The daily net radiation ranged from 59 to 76 percents of the total shortwave radiation under cloudless conditions, which was lower than cloud overcast condition with recorded 63 to 83 percents. The latent heat flux under overcast condition was sometimes larger than the sum of net radiation, implying transportation of energy by advection of ambient air. The linear relationship was obtained between daily or daytime net radiation and evapotranspiration. The evapotranspiration calculated by Bowen ratio-energy balance method was about 150 percent of class A pan evaporation during the growing season. The total solar radiation from June 20 to August 27 was $1043MJm^{-2}$. The 85 percent of the total shortwave radiation was used for evaporative heat. The dry matter production within the period was $836gm^{-2}$ and the water use efficiency was $2.31gDM\;kg^{-1}\;H_2O$.

• Journal of the Korean Burn Society
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• v.21 no.1
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• pp.17-21
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• 2018

Purpose: This study aimed to evaluate the thermal protective function of firefighter clothes and gloves through real scale fire simulations. Methods: Firstly, the fire simulation by real scale flame was performed for firefighter clothes. A manikin equipped with firefighter clothes was directly exposed to flames which energy average is 84 Kw/m². for 22 seconds. Heat flux gauges attached on the body measured surface temperature elevation. Secondly, we also performed the other fire simulation by hot plate exposure to firefighter gloves. Firefighter gloves with heat flux gauges exposed hot plate which temperature is 300℃ in both dry and moist conditions. Primary outcome was surface temperature change of manikin body (first simulation) and hand (second simulation) over times. Results: In the first flame simulation, the surface temperature of face and shoulders elevated more rapidly comparing with the other body surface area when initial period of flame shutter open. After 18sec of shutter open, the surface temperature of upper trunk elevated rapildy. After shutter closure, high surface temperature kept continuously on right side of face and left shoulder. In the second hot plate simulation, fingers and palms showed higher surface temperature than the other areas of hands in the both dry and wet conditions. Conclusion: This study suggests that the real scale flame enables firefighter clothes to lose their heat protective function suddenly after 18 seconds. Additionally, the protective function of firefighter gloves were relatively weaker in the palmar side of fingers than the other parts of hand. There should be additional study for evaluate thermal protection performance of firefighter clothes. And, further effort for reinforce palmar side of fingers of firefighter gloves should be done.

• 한국연소학회:학술대회논문집
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• 2004.11a
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• pp.197-205
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• 2004

Most of gas turbines is operated by the type of dry premixed combustion to reduce NOx emission and economize fuel consumption. However this type operation, combustion induced instability brought failure problems cause by high pressure and heat release fluctuations. Though there has been lots of studies since Lord Rayleigh to understand this instability mechanism and control the instabilities, none of them made matters clear. In order to understand the instability phenomena, a simple experimental study with dump combustor was conducted at the moderate pressure and ambient temperature conditions. From this model gas turbine combustor self-excited instabilities at the resonance mode(200Hz) and bulk mode(10Hz) were occurred and observed at the three points of view; pressure, heat release and equivalence ratio which are acquired by peizo-electric transducer, HICCD camera and acetone LIF respectively. From this results we could see the instability mechanism clear with the account of time scale analysis which explained by the propagation of pressure wave to the upward of mixture stream and convectional transfer of the equivalence ratio fluctuation by this pressure fluctuation.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.7
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• pp.979-982
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• 2003

Two rapeseed meal samples (Sample A, hybrid 5900 and sample B, double low rapeseed No.4) obtained from China and one Canola meal sample obtained from a local crushing plant in Canada were used to investigate the amino acid degradability of rapeseed/Canola meal in rumen and amino acid digestibility of ruminal incubation residues by precision-fed rooster bioassay. Results show that in ruminal incubation the degradation rate of non amino acid nitrogen in crude protein is higher than that for amino acid nitrogen in crude protein, the results also suggest that the degradation rate of amino acid nitrogen in Chinese rapeseed meal sample B was lower than that for Canadian Canola, but that in Chinese rapeseed meal sample A is much close to that for Canadian canola meal. For all amino acids the digestibility of the bypass or residual protein as measured by the precision-fed rooster bioassay tended to be lower for Chinese rapeseed meal sample A than for sample B or Canadian canola meal which had similar digestibility values. However following a calculation of total amino acid availability, involving the digestibility of amino acids in the rumen and rooster bioassay the results are less contradictory. Results indicated that in traditional roasting-expelling process, heat treatment, especially dry heat treatmeat could decrease amino acids degradability in rumen of rapeseed/canola meal, but also may decrease total availability of amino acids of rapeseed/canola meal.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.3
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• pp.448-453
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• 2018

PV module protective film plays an important role in protecting the solar cell from external environment by anti-hydrolysis polyester, UV resistance and mechanical properties. The backsheet was manufactured by using Roll-to-Roll dry laminating process. The backsheet structure is composed of 3 layers, which are PE, PET, and Fluorine polymer films. In this study, we have experimented the variation of thermal conductivities depending on MgO inputs 10% to 25% in order to confirm the dependence of the module efficiencies. High thermal conductive backsheet can increase the module output power efficiency because the heat is dissipated by spreading out the internal heat. Long-term environment weatherability tests were conducted for confirming 25 year reliability in the field such as PCT, UV, and power efficiency degradations. As the evaluation result, high thermal conductivity can be effective for increase of power efficiency of solar panel by using thermal conductive MgO masterbatch.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.4
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• pp.314-339
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• 1982

Fluctuating climate is still most important environmental constrain, although improved modem agricultural technology has succeeded to increase crop production in the world. To stabilize the food production under fluctuating weather conditions, it is very needed to obain the quantitative information of interactions between crops and climate. The main purpose of this paper is three hold. Using the JIBP-data, the dry matter accumulation of rice crops is studied in relation to weather indexes (\SigmaTa and \SigmaSt). Temperature dependence of the yield index of rice is analyzed as to air temperature and water temperature. \SigmaT$_{10}$ -fluctuations are studied using meteorological data at various stations. The possible shift of \SigmaT$_{10}$ -isopleths due to climate fluctuation is evaluated. The second interest is in the plant climate of rice crops. Using results of canopy photosynthesis, it is pointed that the canopy structure has most important implication in plant climate. Leaf-air, stomatal, and mesophyll resistances of rice crops are described in relation to weather conditions. The change in light condition and aerodynamical property of rice crops with the growth is illustrated. The energy partition is also studied at different growing stages. Third point is to show in more detail effective countermeasures against cold irrigation water and cool summer. Heat balance of warming pond and polyethylene tube as a heat exchanger is studied to make nomo-grams for evaluating the necessary area and necessary length. Effects of windbreak net on rice crops are illustrated by using experimental and simulation results.lts.

• Tribology and Lubricants
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• v.22 no.3
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• pp.137-143
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• 2006

The sliding contact interface of machine components such as bearings, gears frequently operates in lubrication at the inception of sliding failure under high loads, speed and slip. The surface temperature at the interface of bodies in a sliding contact is one of the most important factors influencing the behavior of machine components. Most surface failure in sliding contact region result from frictional heat generation. However, it is difficult to measure temperature rise experimentally. So the calculation of the surface temperature at a sliding contact interface has long been an interesting and important subject for tribologist. The surface temperature rise is related in contact pressure, sliding speed, material properties and lubrication thickness. Though roughness, load, ect all of the condition, are same, film thickness varies with velocity. In this study, surface temperature rise due to frictional heating in lubrication is calculated with various velocities. Surface film shearing and dry solid asperity contact are used to simulate the change of frictional heat in lubricated contact