• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2004년도 하계학술발표 논문집
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• pp.224-224
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• 2004

• 대한원격탐사학회지
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• 제36권5_1호
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• pp.667-677
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• 2020

작물 수분 스트레스는 토양수분 함량, 농작물 생리학적 특성 및 원격탐사 기술을 이용하여 감지할 수 있으며, 작물의 생산량 감소를 평가하는데 매우 중요하다. 작물 수분 스트레스 지수(CWSI)는 작물의 엽온과 기온의 차이를 이용하여 산출할 수 있다. 본 연구에서는 드론 기반 열적외 영상을 이용하여 봄배추를 대상으로 관수 처리구(WCP)와 무관수 처리구(WDP)에 대한 CWSI 분포도를 작성하였다. 그 결과, CWSI 공간분포는 배추의 생육이상 반응 요소(구고, 구직경 및 엽록소 함량 측정치)와 높은 일치율을 나타내었다. 따라서 CWSI는 작물 생육이상 모니터링 및 평가에 좋은 수단으로 활용 가능할 것으로 판단된다.

• Journal of Animal Science and Technology
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• 제65권4호
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• pp.878-889
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• 2023

Animal welfare during transport became an largely issue because of increasing demand for improved animal welfare standards. Most studies on the animal welfare during transportation have concentrated on the atmosphere and the temperature of the truck compartments. Thus, the objective of study was to collect and quantify three axis acceleration and determine the effect of bedding for transporting pigs from farm to slaughterhouse. A total of 2,840 crossbred fattening pigs with a live weight of approximately 115 kg were used. They were raised in the same commercial farms and transported to the same commercial slaughterhouse. A 3×2×2 completely randomized factorial design was used to investigate effects of rubber type bedding (bedding or non-bedding) and two levels of driving style (aggressive or normal) in three different time periods with different outside temperatures. Air temperature treatments were as follow: high temperature ([HT] higher than 24℃); low temperature ([LT] lower than 10℃); normal temperature ([NT] 10℃ to 24℃). In our experiment, pigs transported under aggressive driving style showed lower (p < 0.05) pH and water holding capacity (WHC) than those transported under normal driving style. Pigs transported under normal driving style showed a lower percentage of drip loss (DL) (p < 0.05) than those transported with an aggressive driving style. Also, transported with bedding showed higher (p < 0.05) lying behavior but lower (p < 0.05) sitting behavior than those transported without bedding. Pigs transported under normal driving style showed lower (p < 0.05) cortisol level than those transported under aggressive driving style. In conclusion, aggressive driving style cause acute stress in pigs, while bedding helps alleviate acute stress in pigs during transportation in LT.

• Corrosion Science and Technology
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• 제3권5호
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• pp.198-208
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• 2004

Although there has been no general agreement on the mechanism of primary water stress corrosion cracking (PWSCC) as one of major degradation modes of Ni-base alloys in pressurized water reactors (PWR's), common postulation derived from previous studies is that the damage to the alloy substrate can be related to mass transport characteristics and/or repair properties of overlaid oxide film. Recently, it was shown that the oxide film structure and PWSCC initiation time as well as crack growth rate were systematically varied as a function of dissolved hydrogen concentration in high temperature water, supporting the postulation. In order to understand how the oxide film composition can vary with water chemistry, this study was conducted to characterize oxide films on Alloy 600 by an in-situ Raman spectroscopy. Based on both experimental and thermodynamic prediction results, Ni/NiO thermodynamic equilibrium condition was defined as a function of electrochemical potential and temperature. The results agree well with Attanasio et al.'s data by contact electrical resistance measurements. The anomalously high PWSCC growth rate consistently observed in the vicinity of Ni/NiO equilibrium is then attributed to weak thermodynamic stability of NiO. Redox-induced phase transition between Ni metal and NiO may undermine the integrity of NiO and enhance presumably the percolation of oxidizing environment through the oxide film, especially along grain boundaries. The redox-induced grain boundary oxide degradation mechanism has been postulated and will be tested by using the in-situ Raman facility.

• Weed & Turfgrass Science
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• 제7권3호
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• pp.239-245
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• 2018

Comparative drought resistances of 11 perennial warm-season turfgrasses were evaluated in the field after withholding irrigation for 48 days in summer I and 57 days in summer II. There were significant variations among the grasses in their drought resistances. From two years study of field shoot recovery from drought stress, the relative rankings among the 11 warm-season turfgrasses was as follows. 'Arizona Common' and 'Texturf 10' bermudagrasses [Cynodon dactylon (L.) Pers.], 'Tifgreen' hybrid bermudagrass [C. dactylon (L.) Pers. ${\times}$ C. transvaalensis Davy], and 'Georgia Common' centipedegrass [Eremochloa ophiuroides (Munro.) Mack.] possessed good drought resistances, whereas 'Texas Common' St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] and 'Tifway' hybrid bermudagrass [Cyndon dactylon (L.) Pers ${\times}$ C. transvaalensis Davy] possessed poor drought resistances. 'Texas Common' buffalograss [Buchloe dactyloides (Nutt.) Engelm.], 'Pensacola' bahiagrass (Paspalum notatum Flugge.), and 'Adalayd' seashore paspalum (Paspalum vaginatum Swartz), 'Meyer' zoysiagrass (Zoysia japonica Steud.), 'Emerald' zoysiagrass (Z. japonica Steud. ${\times}$ Z. tenuifolia Willd. ex Trin.) were found to rank intermediate. Visual leaf firing showed the highest correlation (r=-0.84) to shoot recovery from drought stress. Visual leaf rolling (r=-0.59) and canopy-air temperature differential (r=-0.64) also showed very significant correlations, whereas leaf water potential (r=0.54) showed relatively lower correlation.

• Computers and Concrete
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• 제11권4호
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• pp.271-289
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• 2013

In this research, a developed microstructural model of cement particles was presented to describe the cement hydration procedure. To simplify the hydration process, the whole hydration was analyzed in a series of sub-steps. In each step, the hydration degree, as well as the microstructural size of the hydration cell, was calculated as a function of the radius of the unreacted cement particles. With the consideration of the water consumption and the reduction of the interfacial area between water and hydration products, the micro-level expressions of the cement hydration kinetics were established. Then the heat released and temperature history of the concrete was carried out with the hydration degree obtained from each sub-steps. The equivalent age method based on the Arrhenius law was introduced in this research. Based on the equivalent age method, a maturity model was applied to describe the evolution of the mechanical properties of the material during the hydration process. The finite element program ANSYS was used to analyze the temperature field in concrete structures. Then thermal stress field was calculated using the elasticity modulus obtained from code formulate. And the risk of thermal cracking was estimated by the comparison of thermal stress and concrete tensile strength.

• 한국해양학회지
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• 제30권5호
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• pp.512-521
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• 1995

표면혼합층의 단기(2시간~24시간)변화를 조사하기 위하여 대한해협의 한 정점에 서 1983년 10월 12일에서 10월 14일까지 48시간 동안 주로 1시간 간격으로 해양과 기 상에 대한 관측을 실시하였다. 표면혼합층의 깊이와 수온을 시간당 변동률이 평균적으 로 각각 5.2 m/hour, 0.2$^{\circ}C$/hour로 해표면에서의 바람 응력, 부력속과의 상관관계가 매우 적다. 표면 혼합층은 표면혼합층의 수온와 염분이 높을 때 깊고, 낮을 때 얕다. 한편, 표면혼합층 수온의 급격한 하강 또는 상승이 관측되었다. 인공위성 자료와 XBT 자료 분석에 의하면 표면혼합층 수온의 급격한 상승은 고온의 해수의 이류에 의한 일 어남을 알 수 있었다. 위의 결과들은 해류가 비교적 강하고 해수물성이 서로 다른 수 괴가 존재하는 가을철 대한해협에서는 해수의 이류가 표면혼합층의 단기변화에 크게 영향을 준다는 것을 나타낸다.

• Journal of Ginseng Research
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• 제6권1호
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• pp.84-99
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• 1982

Water content and its seasonal change in reprodltctive organs were reviewed in relation to cultivation practice s. Precipitati on and humidity under shade roof were reviewed in relation to shading ,jystem and environmental factors. High water content of reproductive organs suggests vulnerability to water stress during reproductive growth stage. Watering during dehisconce treat menu seems to keep optimum temperature but cnoventional practice seems to be too often In watering. Information effe on water physiology of seeds is too rare to develop seed storing method and ctive seed use. Dehiscent mechanism was considered in terms of water absorption of embryo. Precipitation rate of conventional shade roof reaclled to 38% and at line level 50% and varied with shade patterns. Precipitation rate under shade has been investigated for itself but should be investigated in relation to light intensity and soil moisture content Relative humidity under shade depends mainly on air humidity and soil moisture, considerably on shade materials and lithe on pole height, bed width or plant density. Since relative humidity was lower in afternoon it was often less than 50% even in summer with high temperature suggesting possible disorder of phi biological function especially in photosynthesis. More information was needed on optimum humidity for productive physiological function of leaf.

• 한국물환경학회지
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• 제35권2호
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• pp.131-144
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• 2019

Climate Change affects the hydrological cycle in agricultural watersheds through rising air temperature and changing rainfall patterns. Agricultural watersheds in Korea are characterized by extensive paddy fields and intensive water use, a resource that is under stress from the changing climate. This study analyzed the effects of climate change on river flows for Geum Cheon and Eun-San Choen watershed using STREAM, a semi-distributed watershed model. In order to evaluate the performance and improve the reliability of the model, calibration and validation of the model was done for one flow observation point and three reservoir water storage ratio points. Climate change scenarios were based on RCP data provided by the Korea Meteorological Administration (KMA) and bias corrections were done using the Quantile Mapping method to minimize the uncertainties in the results produced by the climate model to the local scale. Because of water mass-balance, evapotranspiration tended to increase steadily with an increase in air temperature, while the increase in RCP 8.5 scenario resulted in higher RCP 4.5 scenario. The increase in evapotranspiration led to a decrease in the river flow, particularly the decrease in the surface runoff. In the paddy agricultural watershed, irrigation water demand is expected to increase despite an increase in rainfall owing to the high evapotranspiration rates occasioned by climate change.

• 한국가금학회지
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• 제47권3호
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• pp.121-126
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• 2020

본 연구는 고온환경에서 이온수의 급수가 산란계의 생산성, 계란 품질 및 혈액성상에 미치는 영향을 구명하고자 시행하였다. 24주령 산란계 180수를 3개 처리구 5반복으로 배치하여 4주간 사양실험을 실시하였다. 각 처리구는 수돗물(tap water; TW)과 냉수(cold water; CW)를 급수하고, 이온수 급수구(ion water; IW)와 비교하였다. 산란계의 생산성은 산란율과 난중을 매일 조사하여 계산하였고, 계란 품질과 혈액성상은 사양실험 종료 후 채집하여 분석하였다. 고온환경에서 이온수 급수로 일반 수돗물에 비해 산란율, 난중 및 사료섭취량은 유의적으로 개선되었고(P<0.01), 계란의 난백 높이와 호우유닛 및 난각 두께도 증가하였다(P<0.05). 혈액성상에서 칼슘과 인은 이온수 급수구에서 증가하는 경향을 보였고(P<0.10), HDL 콜레스테롤과 알부민은 이온수 급수구에서 수돗물에 비해 통계적으로 증가하였다(P<0.05). 본 실험 결과 이온수 급수로 여름철 산란계의 고온스트레스를 완화되었다. 특히 이러한 이온수가 혹서기에 산란계에 미치는 영향은 냉수를 급수한 결과와 유사하였으므로 냉수 급수법과 함께 산란계에 활용될 수 있는 여름철 음용수 관리법으로 가능성을 보였다.