• Journal of Bio-Environment Control
• /
• v.16 no.4
• /
• pp.284-290
• /
• 2007

Thermal insulation effectiveness of the aluminum insulator depending on the direction of its glossing face, number of layer and allocation position was investigated. Modules were assembled by the combination of the variables levels and experimented for the case of 100 W and 40 W heating in the modules. The temperatures in the modules with the aluminum insulator were higher than those of the modules with polyester curtains. For the modules with one layer aluminum insulator, the inside temperatures of the modules with the direction of the glossing face outward were higher than those of the modules of inward. For two layer of aluminum insulator, the directions of those glossing faces were recommended to be the same direction for higher thermal insulation effectiveness. For the modules without heating, the temperature difference between the modules were not significant. The black globe temperatures in the modules were changed with the similar tendencies with the dry bulb temperatures in the modules. Those of the black globes were higher than those of the dry bulb temperatures as a whole. It was more distinguished for the modules of inward direction.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.15 no.5
• /
• pp.1763-1773
• /
• 1991

본 연구에서는 포화수증기와 공기의 혼합기내에서 분무수적으로의 열 및 질량 전달률을 계산하기 위하여 수적의 부분혼합모형과 비혼합모형에 대하여 수적내 과도온 도분포의 해석해를 적용성이 보장되면서도 계산상의 어려움이 수반되지 않는 형태로 구하기 위하여 수적내부의 열전도해석에 있어서 적분법을 적용하였다. 적분법으로 얻어지는 과도온도분포의 해는 유한차의 다항식으로 표시되어 비혼합모형인 경우 각시 간 구간의 경계에서의 온도분포가 연속성을 유지하면서 물성치들의 온도에 대한 종속 성이 쉽게 고려되고 계산도 용이한 형태이다. 본 보에서 제시하는 해석결과의 적용 성을 조사하기 위하여 완전혼합모형을 포함하는 세가지 수적모형들에 대한 계산결과들 로부터 얻어진 시간변화에 따른 수적의 무차원 체적평균온도변동을 유효한 실험결과들 과 비교, 검토하였으며, 부분혼합모형에 대하여 혼합기의 압력, 수적의 초기온도, 혼 합기 속에 포함되어 있는 수증기의 체적분율, 수적의 초기크기, 수적의 초기속도 및 분사각도가 주위혼합기로부터 수적으로 전달되는 열 및 질량전달에 미치는 영향을 조] 사하고 도출된 대표적인 검토 결과를 제시하였다.

• Journal of Animal Environmental Science
• /
• v.11 no.2
• /
• pp.103-110
• /
• 2005

The study was carried out to develop the real time measuring technique of ammonia and carbon dioxide concentration emitted from growing-finishing pig house in winter and estimate ammonia emission rate emitted from the pig house. As the study was carried out, environmental management technique for the pig house and odor abatement skill could be properly developed to reduce the residence's annoyance. The room temperature of the growing-finishing pig house was $10^{\circ}C$ higher than outdoor air temperature in spite of additional heating, because of heat emitted from body temperature of the pigs. The daily variation pattern of room temperature in the pig house shows the similar tendency with outdoor air temperature. The daily mean ventilation rate per head was $16\;m^3/h$ and ranged from $12\;m^3/h$ to $22.4\;m^3/h$. The difference of day and night for ventilation rate was about 2 times. The ammonia emission rate was $208{\pm}28\;mg/h{\cdot}pig$ per daily basics calculated with ventilation rate and ammonia concentration.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2003.03a
• /
• pp.144-144
• /
• 2003

니켈계 내열합금의 성형은 수백 $^{\circ}C$에 이르는 고온에서 이루어지기 때문에 열간성형 과정에서 소재 내부의 미세조직 변화에 대한 이해는 부품의 특성 제어 측면에서 매우 중요하다. 특히 열간 동적 재결정에 의해 발생되는 결정립 구조의 변화를 적절히 조절함으로써 부품의 특성을 극대화 할 수 있다. 본 연구에서는 Ni-Fe계 초내열합금에 대한 고온 압축실험과 압축시편에 대한 EBSD 분석을 통해 열간 변형 과정에서 발생하는 소재 내부의 동적인 결정립 구조의 변화를 정량적으로 분석하고자 하였다. 고온 압축시험은 101$0^{\circ}C$, 1066$^{\circ}C$의 온도 조건과 0.5s-1, 0.005s-1의 변형율 속도 조건에서 최대 진변형율 0.7까지 수행하였으며 진변형율에 따른 결정립 조직 변화를 관찰하기 위해 진변형 율에도 변화를 주어 실험을 수행하였다. 이들 고온 압축시편은 응력방향에 평행한 면에 대한 미세조직 관찰을 통해 재결정립 크기, 분율 및 결정립계의 특성 변화에 대한 정량적 연구를 수행하였다.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
• /
• 2011.11a
• /
• pp.533-536
• /
• 2011

본 연구에서는 차량 연료탱크에 충격탄 관통 시 화재발생 여부를 분석하기 위한 연구의 전단계로서, 충격탄 속도 변화에 따른 연료탱크 내부의 열전달특성을 분석하기 위해 전산유체역학기법을 도입하여 수치해석을 수행한 결과 다음과 같은 결론을 얻었다. 잔류속도 120m/s의 경우, 관통부를 지난 위치에서 최대온도는 약 324.8K를 나타내고 잔류속도 360m/s의 경우, 충격탄이 관통부로 유입되면서 급격하게 증가되어 최고온도 약 382.1K를 나타낸다. 이러한 결과로 미루어 최고 온도가 가솔린 연료의 착화온도보다 높아 화재의 위험성이 있지만 순간적인 온도변화가 심하고 착화시간이 만족되지 않을 것으로 판단된다.

• Proceedings of the KSRS Conference
• /
• 2009.03a
• /
• pp.360-366
• /
• 2009

AQUA/AMSR-E 인공위성 자료를 활용하여 3차원 최적내삽 해수면온도 합성장을 생산하였고 시간평균장과 비교하여 문제점과 한계점을 기술하였다. 3-D SST 합성장은 북태평양 중앙부에서 전체적으로 $0.05^{\circ}C$ 이하의 작은 오차를 보였으나, 위성 결측이 있는 연안에서는 $0.4^{\circ}C$ 이상의 비교적 큰 오차를 유발하였다. 강한 강수나 구름으로 인한 결측이 있는 부분에서는 $0.1\sim0.15^{\circ}C$에 달하는 오차를 보였다. 시간평균장과 비교한 결과, 구름 부근의 화소에서는 해수면온도를 낮게 계산하는 경향이 있었으며, 해수면온도의 공간적 구배를 감소시키는 평활화가 전체적으로 나타났다. 저위도에서 OI SST는 실제 해수면온도에는 없는 불연속성을 만드는 경향이 있었고, 이는 OI 과정에서 사용한 윈도우의 크기와 해양 현상의 수평 규모가 위도에 따라 변화하는데서 기인하였다. 현상의 공간 규모의 척도인 로스비 내부 변형 반경은 북태평양에서 O(1) 정도로 위도에 따른 공간적 변화가 큰 것으로 나타났다. 본 연구는 SST 합성장 생산 과정에 위도와 해수의 수직적 밀도 구조와 밀접한 관련이 있는 해양 현상의 수평적 규모의 시공간적 변동 특성을 고려해야 함을 제시한다.

• Journal of Energy Engineering
• /
• v.26 no.4
• /
• pp.100-106
• /
• 2017

The materials of SUS304 and SS400 are adopted for prediction of workpiece temperature variation according to ambient temperature in a reheating furnace. Five thermocouples were installed in a depth direction inside the material, and the ambient temperature was raised to 1200 Celsius degrees. As a result, the material average temperature reached more than 1150 Celsius degrees, and the surface and inside of workpiece locally showed a temperature difference of more than 10K. In order to verify the experimental results, numerical analysis was conducted by applying a thermal model, and the error of numerical simulation compared with the experimental results was within the range of 15K at the average outlet temperature. Also, the error was relatively higher in the SS400 material, which has a larger specific heat change than the SUS304 material. In conclusion, the workpiece temperature in the reheating furnace can be achieved through the atmospheric temperature control, and it is experimentally proved that the material temperature change according to the atmospheric temperature can be estimated within about 3% error range at the outlet position using a thermal model.

• Journal of the Korean Applied Science and Technology
• /
• v.30 no.4
• /
• pp.790-796
• /
• 2013

The following is the study result of herbal tea roasted at different temperatures between $80{\sim}140^{\circ}C$. Depending on treatment temperature the water content decreased, some carbonization occurred and crude ash content relatively increased. Also crude protein and crude fat changed little. Benzopyrene content (0.17~0.35ppb) showed a tendency to increase with higher treating temperature. From this result, the $B({\alpha})P$ content differed depending on the treatment temperature and raw materials. In case of roasting, the actual inside temperature is around $200^{\circ}C$ but since the surface temperature of the roaster reaches around $2,000^{\circ}C$ some portion of $B({\alpha})P$ content was presumed to be produced from the area that came in contact with this surface. Solid elution rate of herbal tea showed 0.18~0.35%(w/w) and the rate of solid elution decreased with higher roasting temperature. There was no big change in $80{\sim}110^{\circ}C$ treatment section but the solid elution decreased rapidly in $110{\sim}140^{\circ}C$ section. The reason for decreasing solid elution rate at higher treatment temperature is because the compact inner tissue makes elution difficult.

• The Journal of the Petrological Society of Korea
• /
• v.9 no.4
• /
• pp.211-237
• /
• 2000

Major element zoning has been analyzed in garnet porphroblasts obtained from the Grt-St and Ky-Grt-St grade assemblages in Zones I on the northern flank of the Pelham Dome, north central Massachusetts. These porphyroblasts grew during multiple phases of deformation and meta-morphism revealed by the inclusion trail geometry plus the chemical zoning patterns within garnet porphyroblasts. Unusual zoning patterns, including zoning reversals and gradient changes in XMn, zlgzag patterns in Fe/(Fe +Mg) and staircase-shaped patterns in XCa, are coincident with textural truncations and other changes in microstructure within the garnet porphrublasts. Chemical variations in plagioclase, biotite, muscovite and staurolite combined with inclusion trail geometry and petrography reveal that the garnet zoning patterns are modified by combinations of the following. (1) Uni-and divariant reactions involving garnet consumption(Grt+ Chl+Ms=St+Bt+Qtz + $H_2$O) and production(St+Ms + Qtz= Bt+ Grt +A1$_2$$SiO_{5}$ + $H_2$O). (2) Deformation induced episudic ionit dissolution, preferential diffusion and re-distribution during foliation development. (3) P-T changes during growth of the porphyroblasts. The P-T paths combined with petrographic and inclusion trail morphology observations consist of two pattens; (1) heating/compression during NW-SE shortening; and (2) decompression with cooling during NNW-SSE shortening. Based on temperature-time(T-t) geochronological data and late-Paleozoic tectonic model, Alleghanian metamorphism, which is the result of heterogeneous shearing concentrated along the boundary between the Abalone Terrane(Pelham dome) and cover rocks(Bronson Hill Terrane), has produced Ky-St-Ms mineral assemblage during Pennsylvanian(290-300 Ma) in Shutesbury area. However, temperature of alleghanian metamorphism was not high enough to form garnet and staurolite in the Northfiled syncline area. Alleghanian metamorphism has affected only the matrix due to heterogeneous shearing in the study area.

• Korean Journal of Environment and Ecology
• /
• v.32 no.3
• /
• pp.303-312
• /
• 2018

This study was conducted to investigate the relationship between the decrease of forest biomass by forest thinning and the change of temperature in the natural forest by measuring forest biomass and temperature before and after forest thinning in the Pusan National University forest where afforestation had been carried out. We intended to investigate the relationship between the forest biomass, estimated by calculating the Basal area, Crown area and Crown volume using the same formula to the same quadrat before and after forest thinning, and the forest temperature. Temperature measurement was carried out on April 20, 2016 through 28 before forest thinning, July 26, 2016 through November 4 around the time of forest thinning, and April 15, 2017 through May 8 after forest thinning. A temperature data logger was installed to point north at the height of 2.0 m above the ground in the center of the quadrat to record data every 10 minutes during the measurement periods. We used the AWS (Automatic Weather Station) data of the Dongnae-gu area located in the nearby city because it was difficult to set the control group since the whole forest was the subject to the forest thinning. The analysis of the relationship between forest biomass change and temperature showed that the change in temperature inside the forest was the greatest in the midday (12:00 - 15: 00) and was highly correlated with the Crown volume in the forest biomass. The temperature increase was much larger (average $1.91^{\circ}C$) 1 year after forest thinning than immediately after forest thinning (average $0.74^{\circ}C$). The comparison of the decrease rate of Crown volume and the increase in temperature showed that the Pitch pine community, which showed the highest decrease of Crown volume by 15.4%, recorded the highest temperature rise of $1.06^{\circ}C$ immediately after forest thinning and $2.49^{\circ}C$ 1 year after forest thinning. The Pitch pine-Korean red pine community, which showed the lowest Crown volume reduction rates with 5.0%, recorded no significant difference immediately after forest thinning but a temperature rise of $0.92^{\circ}C$ 1 year after forest thinning. The results confirmed that the decrease of forest biomass caused by forest thinning led to a rapid increase of the internal temperature. The fact that the temperature increase was more severe after 1 year than immediately after forest thinning confirmed that the microclimate changes due to the removed biomass cannot be recovered in a short time.