• Food Science and Biotechnology
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• 제14권1호
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• pp.28-31
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• 2005

To extract apple pectins, apple pomace (AP) was extruded under 14 different conditions of screw speed (250-350 rpm), feed rate of 30-40 kg/hr, and 20-30% moisture content using twin-screw extrusion. Response surface methodology (RSM), based on three variables by three-level factorial design, was employed to investigate effects of screw speed, feed rate, and moisture on dependent variables of extrudates, soluble dietary fiber (SDF), yield of anhydrogalacturonic acid ($Y_{AGA}$) representing pectin, and intrinsic viscosity ([${\eta}$]). Second order models were used to generate three-dimensional response surface for dependent variables, and their coefficients of determination ($R^2$) ranged from 0.96 to 0.99. Moisture content showed highest effect on solubilization of AP.

• 공업화학
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• 제28권4호
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• pp.442-447
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• 2017

본 연구에서는 항산화성분을 다량 함유하고 있는 천연물로부터 유효성분을 추출하고, 이를 반응표면분석법을 이용하여 추출공정을 최적화하였다. 또한 감잎과 엉겅퀴로부터 추출된 유효성분의 플라보노이드 함량과 폴리페놀 함량을 측정함으로써 유효성분의 기능성을 평가하였다. 추출공정의 독립변수로는 추출시간, 추출온도, 용매의 비율을 설정하였고, 반응치는 수율, 폴리페놀 함량, 플라보노이드 함량을 확인하였다. 감잎의 경우 추출시간(3.1 h), 주정/초순수 부피비(63.4 vol%), 추출온도($54.6^{\circ}C$)에서 수율(27.7%), 폴리페놀 함량(33.2 mg GAE/g), 플라보노이드 함량(47.8 mg QE/mg dw)의 최적 결과를 얻었으며, 엉겅퀴의 경우에는 추출시간(2.9 h), 주정/초순수 부피비(40.7 vol%), 추출온도($68.4^{\circ}C$)에서 수율(27.0%), 폴리페놀 함량(17.9 mg GAE/g), 플라보노이드 함량(28.8 mg QE/mg dw)으로 예측되었으며, 종합만족도는 71.7%이다.

• 한국농림기상학회지
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• 제15권4호
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• pp.312-319
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• 2013

주어진 작물모형이 기후요소 중 어떤 것에 얼마만큼 반응하는지 상대적인 민감도를 모르는 상태에서 계산결과만으로 미래 전망을 내리는 것은 적절치 않을 수 있다. 본 연구에서는 미래기후전망에 근거한 국내 보리 품종의 민감도 변화 실험을 통해 기온, 강수량, 이산화탄소 농도의 변화가 작물의 생산량에 미치는 상대적인 영향을 분석하였다. 주요 보리 품종(올보리-수원, 알보리-밀양, 새쌀보리-익산, 삼도보리-진주)에 맞게 품종모수가 조정된 CERES-Barley를 RCP 8.5 시나리오의 2071-2100 기후변동범위(1981-2010 기준 기온 $-1^{\circ}C{\sim}+8^{\circ}C$, 강수량 -50% ~ +50%, $CO_2$ 농도 330ppm ~ 900ppm)에 근거한 99개 처리조합에 의해 구동하였다. 이들 처리조합에 의해 생성된 11,880개 종실수량 계산결과를 토대로 각 기후요소의 변화에 따른 종실수량의 민감도를 분석한 결과 이산화탄소농도 변화에 가장 민감한 반응을 보인 반면 강수량 변동에 대한 반응이 가장 무디었고, 온도변화에 대해서는 기준온도대비 상승, 하강 모두 감소하는 경향이었지만 품종 별로 차이가 뚜렷하였다. CERES-Barley는 우리나라에서 농업부문 기후변화 영향평가에 널리 사용되므로 실험설계 시 이러한 모형의 민감도를 감안하여야 현실성 있는 생육모의가 가능하다.

• Earthquakes and Structures
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• 제5권1호
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• pp.23-48
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• 2013

In this study, the effect of flexibility of superstructures and nonlinear characteristics of LRB (Lead Rubber Bearing) isolator on inelastic response of base isolated structures is investigated. To demonstrate the intensity of damage in superstructures, demand response modification factor without the consideration of damping reduction factor, demand RI, is used and the N2 method is applied to compute this factor. To evaluate the influence of superstructure flexibility on inelastic response of base isolated structures, different steel intermediate moment resisting frames with different heights have been investigated. In lead rubber bearing, the rubber provides flexibility and the lead is the source of damping; variations of aforementioned characteristics are also investigated on inelastic response of superstructures. It is observed that an increase in height of superstructure leads to higher value of demand RI till 4-story frame but afterward this factor remains constant; in other words, an increase in height until 4-story frame causes more damage in the superstructure but after that superstructure's damage is equal to the 4-story frame's. The results demonstrate that the low value of second stiffness (rubber stiffness in LRBs) tends to show a significant decrease in demand RI. Increase in value of characteristic strength (yield strength of the lead in LRBs) leads to decrease in the demand RI.

• 한국식생활문화학회지
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• 제34권6호
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• pp.779-784
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• 2019

The purpose of this study was to optimize the rice protein extracted using a response surface methodology. The experiment was designed based on a CCD (Central Composite Design), and the independent variables were the high pressure (X₁, 0-400 MPa) and processing time (X₂, 0-10 minutes). The results of the extraction content (Y₁), residue content (Y₂), and recovery yield (Y₃) were fitted to a response surface methodology model (R²= 0.92, 0.92, and 0.93, respectively). Increasing the pressure and processing time has a positive effect on the extraction content (Y₁), residue content (Y₂), and recovery yield (Y₃). Therefore, these high-pressure conditions (independent variables) can significantly affect the improvement in rice protein extraction efficiency. Thus, the optimal conditions of X₁ and X₂ were 400 MPa and 10 min., respectively. Under these optimal conditions, the predicted values of Y₁, Y₂, and Y₃ were 62.93, 57.53 mg/g, and 91.76%, respectively.

• 한국식품과학회지
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• 제29권4호
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• pp.752-757
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• 1997

Papaya 유액 추출물에서 protein을 정제 회수하기 위해 papaya 유액으로부터 추출한 추출액을 경제적이고도 처리가 비교적 간단한 ethanol 침전방법을 사용하였다. 실험계획법에 의하여 설정된 3수준의 부분요인 실험법에 의하여 실시된 각 처리구의 실험 결과를 다중 회귀분석 방법에 의해 다음과 같은 모델식 $Y=7.4554+1.2657X_{2}+1.0552X_{3}-1.7407X_{4}-0.01666X_{2}\;^{2}-0.1134X_{4}^{2}$을 산출하였으며 pH는 다중 회귀분석에 의해 제거되었다. 반응표면 분석법(RSM)을 이용한 결과 protein을 회수하기 위한 최적 조건으로는 protein 농도가 38.2 mg/ml, 40%의 ethanol 농도, 침전 온도는 $-8^{\circ}C$였다. 이러한 최적 조건에 의한 회수율의 실험치는 68.97%로 예측치인 77.28%에 근접한 결과였다. 또한 유의 수준을 검정하는 자유도와 F-value도 양호한 값(p<0.001)을 나타내어 종속변수와 독립변수와의 상관관계가 뛰어남을 알 수 있으며 따라서 다중 회귀분석에 얻어진 모델식의 각 변수들 사이에는 유의성이 높음을 알 수 있었다.

• 대한토목학회논문집
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• 제41권6호
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• pp.637-644
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• 2021

대부분 동적 성능 평가는 반복 가력 실험을 수행함으로써 구조물의 동적 응답을 평가할 수 있다. 일반적으로 강재는 재하속도 의존성 재료로 알려져 있으며 기둥 부재의 횡방향인 수평방향 가력 시 기둥 부재의 축력인 수직하중이 작용하면 부재의 응답에 영향을 미친다. 하지만, 강재 기둥 구조물의 실험 시 수평 및 수직하중을 동시에 제어하는 것이 어려워 관련 연구는 부족한 실정이다. 본 연구에서는 기둥 부재를 ATS Compensator와 FLB 시스템을 이용하여 수평 및 수직하중을 고속으로 제어하였다. 실험은 H-형 구조용 압연강재인 SS275을 이용하여 수직 하중을 제어하면서 여러 속도로 단조 및 반복 가력 실험을 수행하고 부재의 항복 하중을 비교하였다. 또한, 유한요소해석 시 재하속도에 따라 새로운 항복 응력을 제안하고 수치해석을 통해 비교하였다.

• Steel and Composite Structures
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• 제41권6호
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• pp.831-850
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• 2021

Surface subsidence caused by mining subsidence has an impact on neighboring structures and utilities. In other words, subsurface voids created by mining or tunneling activities induce soil movement, exposing buildings to physical and/or functional destruction. Soil-structure is evaluated employing probability distribution laws to account for their uncertainty and complexity to estimate structural vulnerability. In this study, to investigate the displacement field and surface settlement profile caused by mining subsidence, on the basis of a Winklersoil model, analytical equations for the moment-rotation response ofsoil during mining induced ground movements are developed. To define the full static moment-rotation response, an equation for the uplift-yield state is constructed and integrated with equations for the uplift- and yield-only conditions. The constructed model's findings reveal that the inverse of the factor of safety (x) has a considerable influence on the moment-rotation curve. The maximal moment-rotation response of the footing is defined by X = 0:6. Despite the use of Winkler model, the computed moment-rotation response results derived from the literature were analyzed through the ELM-SVM hybrid of Extreme Learning Machine (ELM) and Support Vector Machine (SVM). Also, Monte Carlo simulations are used to apply continuous random parameters to assess the transmission of ground motions to structures. Following the findings of RMSE and R2, the results show that the choice of probabilistic laws of input parameters has a substantial impact on the outcome of analysis performed.

• 한국작물학회지
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• 제48권4호
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• pp.326-333
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• 2003

Transgenic rice plants expressing a Bacillus subtilis protoporphyrinogen oxidase (Protox), the last shared enzyme of the porphyrin pathway in the expressed cytoplasm or the plastids, were compared with non-trangenic rice plants in their growth characteristics such as tiller number, plant height, biomass, and yield. Transgenic rice plants of $\textrm{T}_3$ generation had 8 to 15 % and 25 to 43% increases in tiller number compared to non-transgenic rice plants at 4 and 8 weeks after transplanting(WAT); similar values were observed for $\textrm{T}_4$ generation at 4 and 8 WAT. However, the plant height in both $\textrm{T}_3$ and $\textrm{T}_4$ generations was similar between transgenic rice plants and non-transgenic rice plants at 4 and 8 WAT. Transgenic rice plants had 13 to 32% increase in above-ground biomass and 9 to 28% increase in grain yield compared to non-transgenic rice plants, demonstrating that biomass and yield correlate with each other. The increased grain yield of the transgenic rice plants was closely associated with the increased panicle number per plant. The percent of filled grain, thousand grains and spikelet number per panicle were similar between transgenic and non-transgenic rice plants. Generally, the growth and yield of transgenic generations ($\textrm{T}_2$, $\textrm{T}_3$, and $\textrm{T}_4$) and gene expressing sites (cytoplasm-expressed and plastid-targeted transgenic rice plants) were similar, although they slightly varied with generations as well as with gene expressing sites. The transgenic rice plants had promotive effects, indicating that regulation of the porphyrin pathway by expression of B. subtilis Protox in rice influences plant growth and yield.

• 한국농공학회논문집
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• 제59권1호
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• pp.71-79
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• 2017

Climate change phenomenon is posing a serious threat to sustainable corn production in Ghana. This study investigated the impacts of climate change on the rain-fed corn yield in the Dangme East district, Ghana by using Aquacrop model with a daily weather data set of 22-year from 1992 to 2013. Analysis of the weather data showed that the area is facing a warming trend as the numbers of years hotter and drier than the normal seemed to be increasing. Aquacrop model was assessed using the limited observed data to verify model's sufficiency, and showed credible results of $R^2$ and Nash-Sutcliffe efficiency (NSE). In order to simulate the corn yield response to climate variability four climate change scenarios were designed by varying long-term average temperature in the range of ${\pm}1^{\circ}C{\sim}{\pm}3^{\circ}C$ and average annual rainfall to ${\pm}5%{\sim}{\pm}30%$, respectively. Generally, the corn yield was negatively correlated to temperature rise and rainfall reduction. Rainfall variations showed more prominent impacts on the corn yield than that of temperature variations. The reduction in average rainfall would instantly limit the crop growth rate and the corn yield irrespective of the temperature variations.