• Title/Summary/Keyword: Ambient Temperature

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Microgravity Combustion Characteristics of Polystyrene Spheres with Various Ambient Gases (분위기 가스 변화에 의한 폴리스틸렌 구의 미소중력 연소특성)

  • Choe, Byeong-Cheol
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.25 no.11
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    • pp.1509-1517
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    • 2001
  • An experimental and numerical analysis were conducted to investigate the transient temperature distribution and flame propagation characteristics over an inline polystyrene spheres under microgravity. From the experimental, a self-ignition temperature of polystyrene bead was 872 K under gravity. Flame spread rates were 4.7-5.1 mm/s with ambient gas N$_2$and 2.3-2.5 mm/s with ambient gas CO$_2$, respectively. Flame radius diameters were 17 mm with ambient gas N$_2$and 9.6 mm with ambient gas CO$_2$, respectively. These results suggest that the flame propagation speed could be affected in the Diesel engine and the boiler combustor by EGR. In terms of the flame spread rate and the transient temperature profile, numerical results have the qualitative agreement with the experiment.

Hydration Heat Analysis of Coping With Ambient and Placing Concrete Temperature (교각 코핑부의 외기온도와 타설온도에 따른 수화열 해석)

  • Yang, Joo-Kyoung
    • Journal of the Korea Computer Industry Society
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    • v.9 no.3
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    • pp.99-104
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    • 2008
  • The thermal stresses due to hydration heat in massive concrete structures are affected by ambient temperature and placing concrete temperature. It is needed to predict the thermal stresses considering ambient temperature and placing concrete temperature. In this study, hydration heat analyses of coping were carried out. After the maximum tensile stress was occurred at 2,75 days the crack index was increased. Therefore the possibility of crack occurrence was rare. The possibility of crack occurrence can be reduced by placing concrete temperature drop. Therefore some method to drop the placing concrete temperature may be effective to reduce the possibility of crack occurrence.

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RABBIT HEATING BY MICROWAVE EXPOSURE AT VARIOUS AMBIENT TEMPERATURES

  • Kolganova, Olga I.;Zhavoronkov, Leonid P.;Petin, Vladislav G.;Kim, Jin-Kyu
    • Journal of Radiation Protection and Research
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    • v.35 no.3
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    • pp.99-104
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    • 2010
  • The potential ability of environmental temperature to enhance the effect of microwave radiation (7 GHz) was experimentally studied for rabbit heating after simultaneous application of both agents. The tested ambient temperatures (30 and $38^{\circ}C$) didn't exert a considerable influence upon rabbit heat homeostasis after the used duration of exposure (3 hours and 15 minutes, correspondingly). The synergistic interaction of microwave irradiation and ambient temperature was demonstrated for rabbit heating. Power flux density of microwave irradiation was shown to be a determinant of the synergistic interaction effectiveness. For the fixed ambient temperature ($30^{\circ}C$), the synergism was shown to be observed only within a definite power flux density ($0-100\;mW{\cdot}cm^{-2}$), inside of which there was an optimal intensity ($20\;mW{\cdot}cm^{-2}$), which maximized the synergistic effect. Any deviation of the power flux density from the optimal value resulted in a reduction of the synergy. It is concluded that any assessment of the health or environmental risks should take into account the synergistic interaction between ambient temperature and microwave radiation.

Dependence of Round Type Electrodeless Lamp according to Ferrite Core and Cold Spot Temperature (둥근형 무전극 램프의 페라이트 코어와 냉점의 온도 의존성)

  • Jang, Hyeok-Jin;Yang, Jong-Kyung;Kim, Nam-Goon;Jung, Young-Il;Park, Dae-Hee
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.22 no.12
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    • pp.1078-1083
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    • 2009
  • Generally Lighting system consists of lamp and luminaire. When a fluorescent lamp is installed in luminaire, power and light output is changed by ambient temperature. Particularly electrodeless lamp depends on the changes that are mercury pressure with amalgam temperature and magnetic properties with ferrite temperature. It has finally influence on optical efficiency. In this study, the temperature change of ferrite and cold spot, vessel are measured at transitional state and then same characteristics are measured with increase of ambient temperature. At transitional state, luminous flux is related to temperature change of cold spot that compare with behavior of mercury pressure and light output. At increase of ambient temperature, we analyzed change that efficiency and electrical, optical characteristics of elecrodeless lamp are related to ferrite core and cold spot temperature.

Thermal Energy Characteristics and Simulation Model Development for Greenhouse Heating System Using Solar Energy (태양에너지를 이용한 그린하우스 난방시스템의 열특성과 시뮬레이션 모델개발)

  • Ro, J.G.;Song, H.K.
    • Journal of the Korean Solar Energy Society
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    • v.21 no.2
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    • pp.27-34
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    • 2001
  • The greenhouse heating system using solar energy has been realized in the protective agriculture in this study in order to analyse the thermal energy characteristics of the system the effects of ambient air temperature, solar radiation, relative humidities and water content of ambient air on the greenhouse air temperature were investigated through computer simulation experimental analysis for validation of the simulation. The results from this study are summarized as follows: 1) The expected values of inside air temperature for the system solar energy were very much close to the experimental values. 2) In the system using solar energy, the expected values of daytime surface temperature of soil by computer simulation were very much similar to the measured values, but those of nighttime were higher than the measured value by almost $2.5^{\circ}C$. 3) Heat loss of daytime was found to be larger than that of night time as much as 2.0 to 4.2 times for the system using solar energy. 4) In the system using solar energy. while the ambient air temperature varied between $-7^{\circ}C$ and $-3.8^{\circ}C$, the temperature of the inside air was maintained between $0^{\circ}C$ and $22^{\circ}C$. 5) At the minimum ambient temperature of $-7^{\circ}C$, the temperature of the inside air was $0^{\circ}C$.

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Greenhouse Cooling by Fog System (FOG SYSTEM 을 이용한 여름철 온실냉방)

  • 서원명
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.41 no.1
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    • pp.60-71
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    • 1999
  • This study was performed to improve underirable warm greenhouse environment by fog cooling system in summer season. The resultsof droplet size analysis and cooling effects for fog cooling system are summarized as follows ; 1. At the pump pressure of 70kgf/$\textrm{cm}^2$ , the mean (SMD) drop size was 22.6${\mu}{\textrm}{m}$ and the maximum and minimum drop size was 45.68${\mu}{\textrm}{m}$ and 1.73${\mu}{\textrm}{m}$ , respectively, and almost all of the drop size was less than 40${\mu}{\textrm}{m}$. 2. The temperature of fog cooling greenhouse with 60% shading was dropped more than 2$^{\circ}C$ below the ambient temperature , while the greenhouse temperature without shading was 1$^{\circ}C$ higher than the ambient temperature. 3. It was found that fog spraying intervals were significantly influential on cooling effect. 4. When the greenhouse was ventilated sufficiently by natural vent system, green house temperature could be maintained by 2.5$^{\circ}C$ lower than the ambient temperature, while it was difficult to drop the greenhouse temperature below ambient temeperature without sufficient ventilation. 5. It was found that the temperature of experimental greenhouse could be maintained 3$^{\circ}C$ to 14$^{\circ}C$ lower that of control greenhouse though there were variations depending on experimental and weather conditions.

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An Experimental Studies on Impingement Spray Characteristic in High Temperature and Pressure Chamber (고온고압용기에서 충돌분무 특성에 관한 실험적 연구)

  • 안병규;류호성;오은탁;송규근;정재연
    • Transactions of the Korean Society of Automotive Engineers
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    • v.10 no.3
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    • pp.36-43
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    • 2002
  • The characteristics of spray has much effect on performance and emissions for automobile, diesel engine, gas turbine and combustion engines. So spray behavior after impinging the wall is very important for prediction the engine performance. This studies examined about impingement spray considering ambient density(18,24,30kg/ms), temperature(293,473K), impingement angle(0,30,45°). The images of impingement spray were obtained by the high speed video camera. After that we analyzed impingement spray characteristics to use this images. In this experiment, we found that 1) The spray width is reduced by increasing the ambient gas density and temperature,2) The growth of downstream is increased by increasing the impingement angle.

Effect of Ambient Temperature on Bovine Erythrocyte Sedimentation Rate as Measured by Angled Capillary Method (경사모세관법에 의한 우의 적혈구침강 속도에 미치는 환경온도의 영향)

  • Kim Kyeong-Jin;Lee Bang-Whan
    • Journal of Veterinary Clinics
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    • v.4 no.1
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    • pp.395-401
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    • 1987
  • In this study, the effect of ambient temperature on the 45$^{\circ}$micro ESR/hr of cattle blood were observed, and a correction chart for correcting observed values at any ambient temperature to standard values at 20$^{\circ}C$ was plotted. Besides, the effect of storage temperature of blood on the 45$^{\circ}$micro ESR/hr was surveyed. The results were as follows: 1. The values of the 45$^{\circ}$micro ESR/hr were increased as the ambient temperature were elevated(P<0.01), and lower the value of PCV, higher the effect of temperature on the 45$^{\circ}$micro ESR/hr was observed(P<0.01). 2. Regression of values of 45$^{\circ}$micro ESR to ambient temperature in all the group of different level of blood PCV showed linear regression with the highly significant coefficient of correlation. With the results, correction chart was drawn as in Fig. 1. 3. In the purpose to verify the reliability of correction chart, observed values of 45$^{\circ}$micro ESR/hr in field(out door) were corrected to values at 20$^{\circ}C$ by the correction chart(Fig. 1), comparing with the observed values at 20$^{\circ}C$ of standard temperature. No significant differences were found between two groups mentioned above. 4. In the study on the effect of storage temperature of the blood on the 45$^{\circ}$micro ESR/hr, group of storage temperature at 5$^{\circ}C$ showed statistically no significant differences untill 24 hours in contrast with standard control group.

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Effect of Sodium Bicarbonate Supplementation on Carcass Characteristics of Lambs Fed Concentrate Diets at Different Ambient Temperature Levels

  • Jallow, Demba B.;Hsia, Liang Chou
    • Asian-Australasian Journal of Animal Sciences
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    • v.27 no.8
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    • pp.1098-1103
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    • 2014
  • The objective of this study was to investigate the influence of ambient temperatures on carcass characteristics of lambs fed concentrate diets with or without $NaHCO_3$ supplementation. A slaughter study was carried on 12 male Black Belly Barbados lambs randomly drawn from a growth trial (35 weeks). The lambs were divided into four equal groups and allotted in a $2{\times}2$ factorial design. The lambs were allotted at random to two dietary treatments of a basal diet (35:65 roughage:concentrate) or basal diet supplemented with 4% $NaHCO_3$ at different ambient temperatures ($20^{\circ}C$ and $30^{\circ}C$) in an environment controlled chamber for 10 days. Lambs were slaughtered for carcass evaluation at about 262 days of age (245 days of growth trial, 7 days adaptation and 10 days of experimental period). Ambient temperature had significant (p<0.05, p<0.05, p<0.01, and p<0.001) effects on meat color from the ribeye area (REA), fat, leg and longissimus dorsi muscles with higher values recorded for lambs in the lower temperature group than those from the higher ambient temperature group. Significant differences (p<0.05) in shear force value ($kg/cm^2$) recorded on the leg muscles showed higher values (5.32 vs 4.16) in lambs under the lower ambient temperature group compared to the other group. Dietary treatments had significant (p<0.01, p<0.01, and p<0.05) effects on meat color from the REA, fat, and REA fat depth ($cm^2$) with higher values recorded for lambs in the $NaHCO_3$ supplementation group than the non supplemented group. Similarly, dietary treatments had significant differences (p<0.05) in shear force value ($kg/cm^2$) of the leg muscles with the $NaHCO_3$ groups recording higher (5.30 vs 4.60) values than those from the other group. Neither ambient temperature nor dietary treatments had any significant (p>0.05) effects on pH, and water holding capacity on both muscles. These results indicated that $NaHCO_3$ supplementation at low ambient temperatures had caused an increase in carcass characteristics leading to significant effect on meat quality.

Effect of Ambient Conditions on Spray Behavior of Gasoline Injector (가솔린 분무 거동에 미치는 분위기 조건의 영향)

  • 이창식;이기형;최수천;권상일
    • Transactions of the Korean Society of Automotive Engineers
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    • v.8 no.2
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    • pp.27-32
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    • 2000
  • The main objective of this work is to investigate the effect of ambient conditions on the spray behavior and spray characteristics of high-pressure fuel injector. For this purpose, the effects of ambient pressure and temperature on the spray characteristics have been studied by applying the analysis of visualization system and phase Doppler particle analyzer. In this experiment, the visualization of spray behavior was performed under various ambient gas conditions and injection parameters such as gas temperature, ambient pressure, injection pressure of injector, and axial distance from the nozzle tip. Based on the investigation results, the spray tip penetration and spray width decrease with the increase of ambient gas pressure in the spray chamber. The effects of the spray parameters on the microscopic characteristics of gasoline spray were discussed.

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