• 생물환경조절학회지
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• 제24권3호
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• pp.243-251
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• 2015

근권부 공기순환 덕트 냉방이 온도 및 생육에 미치는 영향을 구명하고자 고온기 파프리카((Capsicumannum.L. 'Veyron')을 코이어배지에서 수경재배하였다. 냉방시간처리는 24시간 연속 가동한 연속냉방(All-day), 17시부터 다음날 1시까지 8시간 냉방한 야간냉방(Night), 대조구인 냉방 무처리(Control) 등 3 처리하여 온실 상 하부 온도, 근권온도, 엽온, 과실 특성 및 기관 분배율을 측정하였다. 근권부 덕트 냉방하였을 때, 고온기(6월 ~8월) 온실하부(바닥으로부터 40cm)와 상부(바닥으로부터 180cm) 온도, 근권온도는 하강되었다. 대조구와 비교하여 온실하부/상부 온도 차이가 연속냉방에서는 $4.4{\sim}5.1^{\circ}C/2.1{\sim}3.1^{\circ}C$ 하강을, 야간냉방 처리에서는 $3.4{\sim}3.8^{\circ}C/2.2{\sim}2.7^{\circ}C$ 하강되었다. 근권온도는 온실 하부 온도 결과와 유사했으며, 연속냉방($22.8^{\circ}C$)> 야간 냉방($24.1^{\circ}C$) > 대조구($27.7^{\circ}C$) 순으로 온도가 낮았다. 연속냉방 처리에서 덕트 위치(통로, 베드하단)와 송풍 방향($45^{\circ}$, $90^{\circ}$, $180^{\circ}$)에 따른 온도 변화를 측정한 결과 덕트의 위치가 통로에 위치하고 송풍방향이 상향($45^{\circ}$) 또는 수평($180^{\circ}$)인 처리는 지상부 100cm까지의 수직 위치에 따른 온도 차이가 크지 않지 않으면서, 근권부위 온도인 지상 50cm 온도가 낮은 특징을 보였고 베드와 베드 공간 사이로 덕트 송풍 방향이 직각($90^{\circ}$)이였을 때는 바닥과 지상 50cm 부위의 온도가 높고, 지상 100cm 이상 200cm 부위 온도가 상대적으로 낮았다. 연속냉방 또는 야간냉방 처리했을 때 파프리카 엽온은 오후 7시가 오전 9시 보다 엽온 하강이 컸다. 과실 분배율은 대조구(24.4%)에 비해 연속냉방(48.6%)과 야간냉방(45.6%)에서 높았으며, 평균과중, 과수 및 수량도 연속냉방 처리에서 가장 높았다. 한편 야간냉방 처리에서도 고온기 평균 지상부 및 근권온도를 낮추었으나, 누적된 평균온도가 가장 낮은 연속냉방처리에서 과실로의 동화산물 분배율을 높여 파프리카 수량을 증가시킨 것으로 보인다.

• 한국유체기계학회 논문집
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• 제17권5호
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• pp.5-10
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• 2014

In this paper, the experimental study was carried to investigate the effect of angle of the anti-vortex holes on the film cooling effectiveness on a flat plate. The pressure sensitive paint technique was applied to measure the film cooling effectiveness. Two anti-vortex hole angles of $0^{\circ}$ and $15^{\circ}$ with respect to the primary hole were considered, and the simple cylindrical hole case was also tested. The blowing ratio based on the cylindrical hole was 0.5 and the same flow rate was kept for all anti-vortex hole cases. Results showed that the film cooling effectiveness for the anti-vortex hole cases were much higher than that of the cylindrical case. Among the anti-vortex hole cases, $15^{\circ}$ angle anti-vortex hole case showed higher film cooling effectiveness than that by the $0^{\circ}$ angle anti-vortex hole case.

• 공업화학
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• 제10권5호
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• pp.731-736
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• 1999

식물성 천연 유지인 콩기름을 peracetic acid로 에폭시화 시킨 후에 황산 촉매 하에서 메탄올과 반응시켜서 OH-value가 186(mg KOH/g)인 폴리올을 합성하였다. 합성한 폴리올에 계면활성제로는 silicon계 B-8409를, 발포제로는 증류수를, 촉매로는 dimethylcyclohexylamine을, 이소시아네이트로는 polymeric MDI를 사용하여 폴리우레탄 포옴을 합성하였다. 형성된 포옴의 밀도, 압축강도, 압축탄성률, cell의 구조 등을 조사하였다. MDI의 당량비를 변화시켜 가며 포옴을 형성시켜 보았으며, MDI index를 105로 고정하고, 발포제, 계면활성제, 촉매의 양을 각각 변화시켜 가며 포옴을 형성시켜 보았다. MDI index가 증가할수록 밀도와 압축 물성이 증가하였다.

• 대한기계학회논문집B
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• 제24권2호
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• pp.177-187
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• 2000

Measurements of temperature fields and film-cooling effectiveness have been conducted for a shower-head film cooling on the leading edge of a blunt body, which simulates a first-stage turbine stator. In this study, three injection cases are employed for an average blowing ratio based on freestream velocity, M, of 0.5, 1.0 and 1.5. Two (Case 1), four (Case 2) and six (Case 3) rows of normal holes are symmetrically drilled on the three tested circular-cylinder leading edges. The measurements show that regardless of M, the film-cooling effectiveness increases as the injection row is situated at farther downstream location. In Case 1, the film-cooling effectiveness is highest for M = 0.5 and lowest for M = 1.5. On the contrary, in Case 3, the film-cooling effectiveness is highest for M = 1.0 and lowest for M = 0.5. When M = 0.5, the film coverage by the first row of the injection holes deteriorates as the number of the injection row increases. In particular, the film-cooling effectiveness due to the injection through the first row of the holes in Case 3, has a nearly zero value.

• 대한기계학회논문집B
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• 제25권7호
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• pp.933-943
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• 2001

Using a semi-circled blunt body model, the geometrical effects of injection hole on the turbine blade leading edge film cooling are investigated. The film cooling characteristics of two shaped holes (laterally- and streamwise-diffused holes) and three cylindrical holes with different lateral injection angles, 30°, 45°, 60°, respectively, are compared with those of cylindrical hole with no lateral injection angle experimentally and numerically. Kidney vortices, which decrease the adiabatic film cooling effectiveness, appear on downstream of the cylindrical hole with no lateral injection angle. At downstream of the two shaped holes have better film cooling characteristics than the cylindrical one. Instead of kidney vortices, single vortex appears on downstream of injection holes with lateral injection angle. The adiabatic film cooling effectiveness is symmetrically distributed along the lateral direction downstream of the cylindrical hole with no lateral injection angle. But, at downstream of the cylindrical holes with lateral injection angle, the distribution of adiabatic film cooling effectiveness in the lateral direction shows asymmetric nature and high adiabatic film cooling effectiveness regions are more widely distributed than those of the cylindrical hole with no lateral injection angle. As the blowing ratio increases, also, the effects of hole shapes and injection angles increase.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.149-153
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• 2001

This paper describes on the fabrication of Fe-Co hydrophilic magnetic fluids from the waste pickling liquor of steel. By adding with HNO$_3$in the waste liquor oxidation is proceeded from Fe$^{3+}$ion at 6$0^{\circ}C$ with air blowing. Ultra-fine Co-ferrite particles with the mean particle size of 50 $\AA$ were produced at pH 12 after adjusting the ratio of Fe$^{3+}$Co$^{2+}$=7/3(wt%) and Fe-Co particles with the mean particle size of 94 $\AA$ were produced by reducing the Co-ferrite particle with H$_2$at the temperature of 50$0^{\circ}C$. After triple adsorption of oleic acid dodecyl benzene sulfonate(D.B.S.) and tetra methyl ammonium(T.M.A.) ions on the surface of Fe-Co particles Fe-Co hydrophilic magnetic fluid was produced by dispersing the Fe-Co particles in ethylene glycol solution. The magnetization of the Fe-Co hydrophilic magnetic fluid increased with increasing the Fe-Co concentration. The magnetic fluid containing 70% (g/cc) Fe-Co showed 73 emu/g in magnetization at the magnetic intensity of 10 kOe.kOe.e.

• 대한기계학회논문집B
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• 제26권3호
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• pp.384-393
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• 2002

The effects of hole expansion angle and the arrangement of nozzles on a film cooling system for a turbine-blade-shaped surface were experimentally investigated. Liquid crystal with flue-temperature correlation and an image processing system were employed to evaluate surface temperature. Distributions of cooling effectiveness were then presented to figure out the change of heat transfer characteristics with different geometric conditions of cooling-holes. It was found thats the averaged cooling efficiency on the suction surface was maximum with 10 degree of the cooling hole expansion angle. It was also shown that the averaged cooling efficiency on the pressure surface and the averaged cooling efficiency for dual array case were not affected by the hole expansion angle.

• Elastomers and Composites
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• 제35권2호
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• pp.132-137
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• 2000

EPDM 발포체 제조의 충전제로 폐타이어 분쇄고무와 카본블랙을 각각 사용하면서 가황특성 및 기계적 물성을 조사하여 이들을 비교하였다. 그 결과 충전제의 함량이 증가함에 따라 가황시간이 짧아짐을 알았다. 분쇄고무를 충전제로 사용한 경우 충전제의 함량이 30 phr 이상이 되면 발포배율, 인장강도 및 신율이 급격히 감소하였다. 반면에 카본블랙을 사용한 경우는 70 phr이 사용될 때까지 인장강도 및 신율의 급격한 변화는 없었다. 이들을 고려할 때, 분쇄고무의 사용량은 30 phr 미만으로 제한시켜야 함을 알았으며 이는 낮은 계면 접착력 때문이었다. 제조된 EPDM 발포체는 우수한 내노화성을 나타내었다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 춘계 학술논문 발표대회
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• pp.169-170
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• 2015

This study is the experiment for manufacturing the Lightweight non-cement matrix based on the blast furnace slag, paper ash. Materials like cement and blowing agent in foamed concrete is replaced by by-products fro blast furnace slag and paper ash. Further, the experiment was performed by replacing alkali with nature gypsum and α type gypsum by (0, 5, 10, 15, 20) of weight of alkali (wt.%) in order to reduce the amount of expensive alkali-activator. Consequently, in the case of the density, plain showed the lowest density and it seems that specimen adding nature gypsum 5% has the best compressive strength and flexural strength. It is detemined that the strength is lowered in accordance with the α type gypsum replacement ratio is higher. The research that it can supplement the further intensity seems to be needed.

• 한국지형학회지
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• 제23권1호
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• pp.47-60
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• 2016

In this study, datum points measurement have been collected and then weather data have been analyzed to figure out erosion and deposition environmental change around Halmi-island, Baramarae. First of all, it was difficult to analyze geomorphological change which is caused by climate change because of quite short term of collection period of data. However, differences in spatial distribution of erosion and deposition have locally been shown. In all season, the wind is blowing in north and north-west direction mostly except in summer which is shifted to south direction. However, since its ratio which are above 5m/s is much lower than the north and north-west wind, its effect on geomorphological process is very tiny. In order to look at a tendency of erosion and deposition environmental change around Baramarae Halmi-island, the periphery of Halmi-island was classified to east and west part, then accumulated erosion and deposition values have been calculated. As a result, generally, the datum points are located in the west part which are mostly depositional sites. On the other hand, the datum points are located in east part showed the dominant erosion patterns.