• 한국기후변화학회지
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• 제5권3호
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• pp.267-275
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• 2014

A key driver for climate change caused by global average temperature rise is greenhouse gas cumulative emissions that stay for long term in the atmosphere. Although at the moment there is no GHG emission, global warming will continue owing to GHG cumulative emission. In this study, scenarios are developed based on two types of optimistic and conservative diffusion goal. There were a total of 6 alternatives scenarios. The objective of this study are to compare scenarios in terms of GHG cumulative emissions and alternative fuels. An object of analysis is the residential buildings and time frame of scenarios is set up by 2030. And this study uses the LEAP model that is a bottom-up energy model. In conclusion, It is important to set specific diffusion pathway for mitigating climate change virtually.

• 한국농림기상학회지
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• 제10권1호
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• pp.25-31
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• 2008

초지피복 조건에서 사면의 일사수광량 차이가 일 최고기온에 미치는 영향을 파악하기 위해 2007년 하지부터 동지까지 밑면지름 570m, 높이 90m인 원추형 기생화산 "높은오름"의 측면 경사 8 지점에서 일 최고기온을 측정하였다. 8개 지점 평균값을 기준온도로하여 각 지점의 기온편차를 구해 비교한 결과 기온편차는 하지로부터 동지로 갈수록 커지는 경향이었고, 관측기간 평균은 남향사면에서 $1.0^{\circ}C$, 북향사면에서 $-0.8^{\circ}C$로서 그 차이가 평균 $1.8^{\circ}C$에 달했다. 기온편차의 월별 평균은 11월에 가장 크며 남향사면에서 $2.1^{\circ}C$, 북향사면에서 $-1.3^{\circ}C$였다. 일별 기온편차의 최대값은 남향사면에서 $3.8^{\circ}C$, 북향사면에서 $-2.7^{\circ}C$에 달했는데, 이러한 기온편차 변이는 일사수광량 편차에 근거한 지형특성지수와 높은 상관을 보여 복잡지형의 일 최고기온 추정모형 개발에 활용될 수 있을 것으로 기대된다.

• 생태와환경
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• 제50권3호
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• pp.275-285
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• 2017

기온과 강수량의 변화에 따른 저서성 대형무척추동물 우점종의 변화를 알아보기 위하여, 섬진강 본류 20지점을 대상으로 2013년과 2014년 5월과 9월 년 2회씩 총 4회에 걸쳐 조사하였다. 서식환경에 중요한 요인으로 작용하는 기온, 강수량, 수질요인과 하상 구성을 수집하고 측정하였다. 섬진강의 평균기온은 2013년에 비해 2014년 $0.2^{\circ}C$증가하였고, 상류에서 하류로 갈수록 기온이 증가하는 양상이 뚜렷하여 $3^{\circ}C$ 이상의 차이를 보였다. 또한 연 누적강수량 (ACP)도 저위도로 갈수록 증가되었다. 섬진강은 강우 전 5월 ($7.6{\sim}11.3^{\circ}C$)에 비하여 강우 후 9월($21.7{\sim}24.5^{\circ}C$)에 기온이 2배 이상 높아지며, CP는 강우 전(263 mm~287.5 mm)과 강우 후(756.3 mm~882 mm)에 약 3배 증가하는 것으로 나타났다. 여름철 집중 강우로 인한 유실효과로, 개체수와 종 수는 5월이 9월보다 높았다. 5월은 깔따구류와 세갈래하루살이, 9월은 네점하루살이, 큰줄날도래, 세갈래하루살이가 우점을 차지하였다. 생물지수와 환경요인 간의 상관성 분석 결과, 하상 구성 중 호박돌 및 모래와 높은 상관성이 있는 것으로 나타났다. 섬진강의 기온과 CP, 우점종 출현과의 집괴분석한 결과 강수량과 기온에 따라 2그룹으로 크게 나뉘었으며, 우점종과 지리적인 위치가 반영되어 세부적인 그룹으로 나뉘어짐을 파악하였다.

• 인터넷정보학회논문지
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• 제20권1호
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• pp.39-46
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• 2019

This paper investigates the importance of various environmental factors that have a strong influence on strawberry yields grown in greenhouse using the pattern recognition methods. The environmental factors influencing the production of strawberries were six factors such as average inside temperature, average inside humidity, average $CO_2$ level, average soil temperature, cumulative solar radiation, and average illumination. The results of analyzing the observed data using Dynamic Time Warping (DTW) showed that the most significant factor influencing the strawberry production was average soil temperature, average inside humidity, and cumulative solar radiation. Second, the results of analyzing the observed data using Multidimensional Scaling (MDS) showed that the most influential factors on the strawberry yields, such as average $CO_2$ level, average inside humidity, and average illumination were differently given for each farms. However, these results are based on the distance in 3D space and can be deduced from the fact that there is not a large difference between these distances. Therefore, in order to increase the harvest of strawberries cultivated in the farms, it is necessary to manage the environmental factors such as thoroughly controlling the humidity and maintaining the concentration of $CO_2$ constantly by ventilation of the greenhouse.

• 플랜트 저널
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• 제18권4호
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• pp.48-57
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• 2023

본 연구에서는 희박예혼합 연소방식을 채택하고 있는 F급 가스터빈에서 연소불안정을 사전에 감지하기 위한 운전관리 개선방안에 대해 고찰했다. 가스터빈 출구에 방사형으로 설치된 16개의 날개통과온도 열전대 데이터를 수집하여 개별 날개통과온도 변화량을 분석하였다. 정상 연소상태 조건의 일주일간 개별 날개통과온도 누적변화량은 최대 26℃로 확인됐다. 반면 연소불안정 발생 시에는 대부분 수일 전부터 개별 열전대에서 온도변화량이 증가하는 전조증상을 확인할 수 있었다. 따라서 기존의 날개통과온도 최대편차 운전관리와 함께 개별 날개통과온도 변화량 감시방법을 추가하면 연소불안정을 조기에 인지할 수 있다. 본 연구결과를 바탕으로 개별 날개통과온도가 10일간 누적변화량 50℃ 이상 초과 시에 점검 및 정비를 하는 것이 적정한 관리기준으로 판단된다.

• 한국철도학회논문집
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• 제9권6호
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• pp.695-700
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• 2006

This study investigates the effects of the material properties and the fatigue behavior in the SM490A material specimens due to the low-temperature atmosphere. In the fatigue behavior, the low-temperature affects the fatigue life. As the temperature get low, the fatigue limit increase, also As the yield strength and the tensile strength increase, the impact absorbed energy decrease. The difference of fatigue lift represents to normal distribution and it is larger between the room temperature and the low temperature, but in the result of the cumulative density function, the effect of temperature is not too large on it.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2006년 창립20주년기념 정기학술대회 및 국제워크샵
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• pp.141-144
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• 2006

In this study, the friction and wear characteristics of pure epoxy and silica-filled epoxy resin composites with average silica particle diameter of $6-33{\mu}m$ were investigated at ambient temperature by pin-on-disc friction test. The cumulative wear volume, friction coefficient and wear rate of these materials against SiC abrasive paper were determined experimentally. The cumulative wear volume tended to increase nonlinearly with increase of sliding distance and depended on diameter of the silica particle for all these composites. The sliding wear tests of the materials demonstrated that the friction coefficient and the wear rate of silica filled epoxy composites were lower than those of the pure epoxy. silica filled epoxy.

• 한국해양공학회지
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• 제22권6호
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• pp.35-40
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• 2008

The effect of counterpart roughness on abrasive wear characteristics of side plate materials of FRP ship, which were composed of glass fiber and unsaturated polyester resin composites, were investigated at ambient temperature by pin-an-disc friction test. The friction coefficient, wear rate and cumulative wear volume of these materials against SiC abrasive paper were determined experimentally. The wear rate of these materials decreased rapidly with sliding distance and then maintained a constant value. It was increased as counterpart roughness was rougher in a wear test. The cumulative wear volume tended to increase nonlinearly with sliding distance and depended on applied load and sliding speed for these composites. It could be verified by SEM photograph of fracture surface that major failure mechanisms were overlapping layers, microcutting, deformation of resin, delamination, and cracking.

• 수산해양기술연구
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• 제50권2호
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• pp.162-168
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• 2014

The friction and wear characteristics of the rubber matrix composites filled with nano sized silica particles were investigated at ambient temperature by pin-on-disc friction test. The volume fraction of silica particles was 19%. The cumulative wear volume and wear rate of these materials on counterpart roughness were determined experimentally. The major failure mechanisms were lapping layers, deformation of matrix, ploughing, debonding of particles, fracture of particles and microcracking by scanning electric microscopy photograph of the tested surface. The cumulative wear volume showed a tendency to increase with increase of sliding distance. The wear rate of these composites tested indicated low value as increasing the sliding distance.

• 동력기계공학회지
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• 제6권1호
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• pp.55-60
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• 2002

There has been no report on the life prediction for gas turbine materials at high temperatures based on the creep properties and their relationship with the AE(acoustic emission) properties as a means of real-time non-destructive testing. One of the important issues is thus to develop a reliable method of evaluating creep properties by the AE technique. In this paper, the real-time evaluation of high temperature creep time and AE cumulative counts for nickel-based superalloy Udimet 720 was performed on round-bar type specimens under pure load at the temperatures of 811, 922 and 977K. The total AE cumulative counts until the starting point of secondary creep($N_1$) and that of tertiary creep($N_2$) have quantitative relationship with the tertiary creep time and the rupture time. It is thus possible to construct the life prediction system based on creep and the prevention system of tertiary creep by using AE technique.