• 한국산림과학회지
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• 제95권2호
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• pp.168-173
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• 2006

Stem respiration rate ($R_{stem}$) was examined using an open flow system on black locust (Robinia pseudoacacia L.). $R_{stem}$ exponentially increased with increasing air and stem temperature during measurement period and was most closely correlated with stem temperature. It was more closely correlated with stem temperature observed 0.5-2.0 hrs earlier than with current stem temperature, that is, there was time lag between the increase of stem temperature and the efflux of $CO_2$ from stem. $R_{stem}$ gradually increased from spring to summer, and then decreased during autumn. $R_{stem}$ ranged from 0.13 to $4.44{\mu}mol$ $CO_2m^{-2}s^{-1}$. $Q_{10}$ decreased with increasing stem temperature, and varied along position (or diameter) within trees during the same period, especially during the growing season. On the other hand, time lag was shortened with increasing temperature.

• Bulletin of the Korean Chemical Society
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• 제29권3호
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• pp.555-561
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• 2008

In air stripping of ammonia from the aqueous solution, a new removal model was presented considering the equilibrium principles for the ammonia in aqueous solution and between the aqueous and air phase. The effects of pH, temperature and airflow rate on the ammonia removal were evaluated with the model. In addition, the saturation degree of ammonia in air was defined and used to evaluate the effect of each experimental factor on the removal rate. As pH (8.9 to 11.9) or temperature (20 to 50 oC) was increased, the overall removal rate constants in all cases were appeared to be increased. Our presented model shows that the degrees of saturation were about the same (0.45) in all cases when the airflow condition remains the same. This result indicates that the effect of pH and temperature were directly taken into consideration in the model equation. As the airflow increases, the overall removal rate constants were increased in all cases as expected. However, the saturation degree was exponentially decreased with increasing the airflow rate in the air phase (or above-surface) aeration. In the subsurface aeration the saturation degree remains a constant value of 0.65 even though the airflow rate was increased. These results indicate that the degree of saturation is affected mainly by the turbulence of the aqueous solution and remains the same above a certain airflow rate.

• 한국환경과학회지
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• 제4권1호
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• pp.41-52
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• 1995

The effects of reaction temperature, SO2 and CO2 concentration in an air gas stream, particle sizes of limestone on the reactivity and capacity of SO2 removal have been determined in a thermogravimetric analyser(TGA). The apparent reaction order of sulfation reaction of pre-calcined lime(CaO) with respect to SO2 is found to be close to unity. The apparent activation energies are found to be 17,000 kcal/kmol for sulfation of pre-calcined lime and 19,500 kcal/kmol for direct sulfation of limestone(CaCO3). The initial sulfation reaction rate of pre-calcined lime increases with increasing temperature, whereas the sulfur capture capacity exhibits a maximum value at 90$0^{\circ}C$. In direct sulfation of limestone, sulfation reactivity and sulfur capature capacity of sorbent increase with increasing temperature and decreasing CO2 concentration in a gas bulk stream. The main pare of pre-calcined lime is shifted to the larger pore sizes and pore volume decreases with increasing sulfation time and temperature. The surface area of lime decreases with increasing calcination temperature under an air atmosphere, whereas is yearly constant under a CO2(5, 10%) atmosphere in a gas stream.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 B
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• pp.624-626
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• 1993

The Electrical Charge generated by friction in flowing insulating oil can create hazadous accidents. Neutralization of static charges in the oil during transportation is an obvious method of overcoming the problem of internal electric charge. It is known that SCR(Static Charge Reducer) can neutralize much of this charge by the needle electrode and mixing it with the original charge. In our experiment, a filter to generate static charge was set just befor a measurement pipe, and streaming current from the filter to the earth $I_s$, current from the electrode to the earth $I_e$ and current from the receiving tank to the earth $I_f$ were measured in a steady state. As a result, charge density and needle electrode current increases with increasing of oil temperature. Charge elimination rate decreases with increasing of oil flow rate, and increases with increases of oil temperature. Faraday Cage current decreases with increasing of oil temperature.

• 폴리머
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• 제26권4호
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• pp.516-522
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• 2002

4급 암모늄기를 관능기로 갖는 아민화 아크릴계 이온교환섬유를 이용하여 연속식 흡착공정 중 linear alkylbenzene sulfonate(LAS)의 흡착특성을 확인하였다. 아민화 아크릴계 이온교환섬유의 LAS흡착성능은 온도가 증가함에 따라 증가하였으며 $40^{\circ}C$에서 최적 흡착성능을 나타내었다. 또한 컬럼 베드 충진비(L/D)의 변화에 따른 LAS 이온의 흡착능은 L/D>2에서 최대 흡착능을 나타내었다. pH 변화에 따른 LAS이온 흡착능은 pH가 증가함에 따라 증가하는 경향을 나타내었고, pH 7에서 최대 흡착능을 나타내었다. 유속변화에 따른 LAS 흡착능은 유속이 증가할수록 낮아졌으며 농도가 높을수록 떨어졌다.

• Journal of Animal Science and Technology
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• 제61권3호
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• pp.163-169
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• 2019

Detection of estrus is an essential factor as a method of successful breeding in the sow. As increasing the adaption of the information and communication technology (ICT) into swine industry, this study focuses on a possibility and quantification of standing time, vulva and body temperature as methods of estrus detection, comparing each time and temperature in estrus and non-estrus period, and analyzing each success rate of new and existing methods. Ultrasonic sensor array and digital infrared thermography were used to evaluate whether new methods such as standing time and number, and vulva and skin temperature can be replaced, or these methods can be quantifiable in estrus period. Ultrasonic sensor array was installed beside the stall and digital infrared thermography was placed in the rear of sow to collect the dates of sow in estrus and non-estrus period. This study showed total standing time, number and number over 10 minutes, and vulva temperature of the sow in estrus period were increased (p < 0.05) compared with those of sow in non-estrus period, respectively. Detection of estrus using standing time and vulva temperature tended (p = 0.06) to increase the success rate when artificial insemination (AI) was performed. In conclusion, standing time and vulva temperature increased when estrus happened. Success rate of AI of sow using these methods showed an increasing trend. Therefore, existing method using the naked eye can be replaced to new method such as vulvar temperature and standing time when detecting the estrus.

• 한국건설순환자원학회논문집
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• 제6권2호
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• pp.89-96
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• 2011

본 연구는 플라이 애시의 치환범위 상향에 따른 콘크리트의 제반 특성을 분석하여 추후 성능 향상을 위한 기초자료로 제공하기 위해 플라이 애시의 치환범위 0-40 % 및 양생 온도 $5-35^{\circ}C$에 따른 기초적 특성을 분석하였다. 그 결과 유동성은 FA의 증가에 따라 비례적으로 증가하였으나, 공기량은 감소하였다. 응결시간은 치환율 증가 및 저온일수록 지연되는 특성을 나타냈으며, 간이단열온도이력은 FA 치환율이 40 %까지 증가함에 따라 최고온도는 $8^{\circ}C$정도 낮아졌고, 최고온도 도달시간은 13시간 정도 지연되는 것을 알 수 있었다. FA 치환 상향에 따른 압축강도는 양생온도가 높을수록 플레인 대비 강도증진성이 향상됨을 알 수 있었다. 중성화의 경우는 FA 치환율이 증가할수록 깊이가 점차 커지는 것을 알 수 있어 중성화 대책에 대한 지속적인 연구가 필요할 것으로 판단되었다.

• 동력기계공학회지
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• 제21권2호
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• pp.89-94
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• 2017

Pneumatic systems are widely applied in various industry because it have a many advantage(low cost, high safety, etc.). Air compressors supply the working fluid to the pneumatic systems and consume a lot of electrical energy at the manufacturing site. The one of the suggested idea is to reduce the energy consumption by reducing the suction temperature of the air compressor and increasing the discharge flow rate. In this paper, the discharge flow rate and air power of the positive displacement type air compressor is simulated by changing the temperature of suction air and the relationship between the suction air temperature and the performance variation of the air compressor is analyzed. As a result, we know that as the suction temperature of air is lowered, the discharge mass flow-rate is increased, but the specific enthalpy is reduced rather than increased, which means that the power of the discharged air is not greatly increased even if lower the suction air temperature.

• 한국연소학회지
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• 제18권4호
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• pp.12-20
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• 2013

The ignition delay time is an important factor to understand the combustion characteristics of internal combustion engine. In this study, ignition delay times of cool and thermal flame were observed separately in homogeneous charge compression ignition(HCCI) engine. This study presents numerical investigation of ignition delay time of n-heptane and alcohol(ethanol and n-butanol) binary fuel. The $O_2$ concentration in the mixture was set 9-10% to simulate high exhaust gas recirculation(EGR) rate condition. The numerical study on the ignition delay time was performed using CHEMKIN codes with various blending ratios and EGR rates. The results revealed that the ignition delay time increased with increasing the alcohol fraction in the mixture due to a decrease of oxidation of n-heptane at the low temperature. From the numerical analysis, ethanol needed more radical and higher temperature than n-butanol for oxidation. In addition, thermal ignition delay time is sharply increasing with decreasing $O_2$ fraction, but cool flame ignition delay time changes negligibly for both binary fuels. Also, in high temperature regime, the ignition delay time showed similar tendency with both blends regardless of blending ratio and EGR rate.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1644-1648
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• 2002

The relationships between MgO deposition conditions and firing voltage of AC PDP were investigated as a function of ambient temperature. Substrate temperature and growth rate were selected as the major parameters that can affect the properties of MgO most significantly. Firing voltages increase with increasing temperature regardless of deposition conditions of the MgO layer. However, the relative magnitude of the firing voltage variation decrease with increasing substrate temperature and decreasing deposition speed. It was also found that the sample obtained at the condition of lower deposition rate shows better dynamic margin characteristics.