• Structural Engineering and Mechanics
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• 제46권1호
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• pp.19-37
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• 2013

The optimum design of base isolation system considering model parameter uncertainty is usually performed by using the unconditional response of structure obtained by the total probability theory, as the performance index. Though, the probabilistic approach is powerful, it cannot be applied when the maximum possible ranges of variations are known and can be only modelled as uncertain but bounded type. In such cases, the interval analysis method is a viable alternative. The present study focuses on the bounded optimization of base isolation system to mitigate the seismic vibration effect of structures characterized by bounded type system parameters. With this intention in view, the conditional stochastic response quantities are obtained in random vibration framework using the state space formulation. Subsequently, with the aid of matrix perturbation theory using first order Taylor series expansion of dynamic response function and its interval extension, the vibration control problem is transformed to appropriate deterministic optimization problems correspond to a lower bound and upper bound optimum solutions. A lead rubber bearing isolating a multi-storeyed building frame is considered for numerical study to elucidate the proposed bounded optimization procedure and the optimum performance of the isolation system.

• 한국식품영양학회지
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• 제29권4호
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• pp.480-485
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• 2016

This study was conducted to develop food for the elderly, which is easier to chew and swallow, using gelification. Various foods for the elderly with chewing and swallowing difficulties were used for sensory assessment. The sensory panel consisted of 10 dieticians (10 women) working in nursing care facilities. The sensory optimal composite recipes were determined by the central composite design (CCD). The optimum formulation of hot pepper paste stir fried pork calculated by the numerical and graphical method was 1.48 g of sugar and 18.97 g of hot pepper paste. The optimum formulation of seasoned spinach was 8.0 g of sesame oil and 5.41 g of soy sauce. Moisture content, hardness, and adhesiveness of hot pepper paste stir fried pork was 76.49%, 2.50, and -1.20, respectively. Moisture content, hardness, and adhesiveness of seasoned spinach was 83.48%, 2.27, and -1.17, respectively. This study provides the basic materials for the development of easily chewable and swallowable foods for the elderly, which can reduce the risk of food going down the wrong pipe, and the preference can be improved by eating solid food instead of porridge or liquid food. The development of food for the elderly, which takes the difficulties in chewing and swallowing among the elderly into consideration and reflects their preference and has sufficient amount of nutrients, is important to enable the elderly to enjoy their meals and it is one of the biggest challenges in Korea, as Korean society is aging rapidly.

• Journal of the Korean Wood Science and Technology
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• 제35권4호
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• pp.38-44
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• 2007

환경문제의 대두에 따라 포름알데히드를 방산하는 접착제를 대신할 수 있도록 로진을 이용한 천연접착제를 개발하고자 한다. 경화속도와 접착물성을 향상시키기 위해 건조제의 배합에 따라 천연접착제를 제조하였다. 건조제의 배합에 따른 경화속도와 접착물성을 Texture Analyzer를 이용하여 얻어진 tack값과 single lap shear test를 통해 얻어진 접착력을 기반으로 평가하였으며, 외국에서 사용되고 있는 AURO, BioFa, Livos의 식물계 천연접착제와의 성능을 비교 분석하였다. 최적의 배합비는 Co 0.7 part, Zr 1.0 part, Ca 0.5 part, Activ8 0.1 part를 첨가하였을 때이며, 이 때의 접착력은 $93.2{\pm}19.1N/cm^2$의 수준에 도달하였다.

• 한국식품영양과학회지
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• 제32권7호
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• pp.1032-1038
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• 2003

전갱이 육으로 제조한 알칼리 수리미의 가열 겔 강도 증강을 위한 최적 전분 및 비근육 단백질의 선정과 이들 성분의 최적 첨가량을 설정하기 위해 2수준 fractional factorial과 mixture design을 실시하였으며, 반응 값은 punch test에 의한 물성과 색차계로 색을 측정하였다. 감자, 옥수수 및 밀전분은 파괴 강도 값을 감소시키지만 변형 값에는 유의적인 영향을 미치지 않는 것으로 나타났다. 소혈청 단백질은 파괴강도 값을 크게 증가시킨 반면 분말 난백 단백질은 다소 효과가 인정되었고 유장단백질과 대두 농축 단백질은 효과가 없었다. 그리고 소 혈청 단백질은 변형값을 다소 증가시킨 반면 분말 난백 단백질을 크게 감소시켰다. 감자와 옥수수 전분과 비근육 단백질은 백색도를 다소 개선하였다. 파괴강도 110g 이상, 변형 값 4.2 mm이상, 백색도 22.5 이상을 보이는 수리미, 옥수수전분 및 소혈청의 최적 혼합 비율은 각각 89.5∼90.0%, 4.6∼6.0%, 4.3∼5.4%의 범위였다. 전분과 비근육 단백질을 첨가하여 제조한 전갱이 알칼리 수리미의 가열 겔이 수세 수리미 겔에 비하여 균일한 단백질 분포를 보이고 있었다.

• Composites Research
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• 제31권1호
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• pp.8-11
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• 2018

섬유강화 복합재료 제조 방법 중 sheet molding compound(SMC)는 자동차에 적용 가능성이 가장 높은 소재이다. 본 연구에서는 저비중 필러인 유리버블과 강화재인 유리섬유를 사용하여 물성이 저하되지 않으면서 낮은 비중을 나타내는 SMC의 제조를 위한 최적의 배합비에 대해 연구하였다. SMC 내부에 유리섬유의 혼입양이 증가할수록 강도가 향상하였고, 유리버블의 혼입양이 증가할수록 비중이 낮아졌다. 최적의 배합에서는 비중이 낮아지면서 물성이 향상되는 시너지 효과가 나타남을 발견하였다. 이러한 시너지 효과는 유리버블의 크랙 전파의 분산효과와 유리버블의 혼입에 따른 섬유와 매트릭스의 결합력의 향상에 기인한 것임을 내부구조 분석을 통해 확인하였다.

• 청정기술
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• 제12권1호
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• pp.27-35
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• 2006

본 실험은 에폭시계 분체도료의 물성에 영향을 미치는 에폭시 수지, 경화제, 충전제 및 안료 의 최적 조성 결정에 대한 연구이다. 본 연구에서 사용된 에폭시계 수지의 경화 시스템은 Diglycidyl ether of bisphenol-A (DGEBA)와 경화제로 dicyan diamide (DICY)를 사용하였다. 코팅 재료의 경화거동과 유변물성은 DSC와 레오메터를 사용하여 조사되었다. 또한 코팅재료의 스틸에 대한 접착력은 lap shear 실험을 이용하여 조사되었다. 연구 결과에 따르면 에폭시계 분체도료의 최적 조성은 에폭시계 수지 기준으로 DICY 6 phr, $CaCO_3$ 20 phr 및 $TiO_2$ 10 phr 이었다.

• Steel and Composite Structures
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• 제29권3호
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• pp.363-377
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• 2018

An efficient and free of shear locking finite element model is developed and employed to study free vibration of tapered bidirectional functionally graded material (BFGM) beams. The beam material is assumed to be formed from four distinct constituent materials whose volume fraction continuously varies along the longitudinal and thickness directions by power-law functions. The finite element formulation based on the first-order shear deformation theory is derived by using hierarchical functions to interpolate the displacement field. In order to improve efficiency and accuracy of the formulation, the shear strain is constrained to constant and the exact variation of the cross-sectional profile is employed to compute the element stiffness and mass matrices. A comprehensive parametric study is carried out to highlight the influence of the material distribution, the taper and aspect ratios as well as the boundary conditions on the vibration characteristics. Numerical investigation reveals that the proposed model is efficient, and it is capable to evaluate the natural frequencies of BFGM beams by using a small number of the elements. It is also shown that the effect of the taper ratio on the fundamental frequency of the BFGM beams is significantly influenced by the boundary conditions. The present results are of benefit to optimum design of tapered FGM beam structures.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.107.1-107
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• 2003

The fermentation process and subsequent processing determine the efficacy of a bioherbicide propagule. Large batches of biomass of the mycoherbicide agent for white clover, Sclerotium sp.(BWC98-105) was produced in simple liquid fermentator in 5 gallons vessels(Model No. 8087, Dabo Inc., Korea) with oxygen supply(DPH16000, FineTech Inc., Korea) simulating industrial conditions by utilizing commercially available, inexpensive ingredients (10 ％ rice bran), The maximum biomass yield of Sclerotium sp.(BWC98-105) was obtained after 5 days of air pumped incubation at room temperature condition(22-28$^{\circ}C$). By using this simple facility, it could get fragmented or proliferated greatly and attained maximum mycelia biomass. The biomass of mycoherbicide agent consisted of hyphae devoid of spores. Biomass mycelia of the fungus 99％ survival at room temperature after 2 me. A thorough understanding of the effects of fermentation and formulation on viability and virulence is required to guide these processes. After an economical yield level of bioherbicide propagule has been achieved in a fermentation process, formulation becomes a critical factor which influences product efficacy. Because the fermentation must be stopped at a point when virulence/viability are optimum, the live bioherbicide propagule must be stabilized, formulated, and packaged.

• Journal of Pharmaceutical Investigation
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• 제41권1호
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• pp.1-7
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• 2011

The effects of different formulation variables including pressure sensitive adhesive (PSA), permeation enhancer, thickness of the matrix and loading amount of drug on the transdermal absorption of galantamine were investigated across the hairless mouse skin. The permeation profile of galantamine was different depending on the types of PSA, loading amount of drug, thickness of the matrix and type of enhancer used. Highest flux of galantamine was obtained from acrylic PSA but crystals were formed in the patch within 72 h. Among the PSAs screened, crystal formation was not observed only in the patches formulated in Styrene Butadiene Styrene (SBS) matrix. Permeation rate increased linearly as the concentration of galantamine in SBS matrix increased from 2.5 to 15% w/w. Among the enhancers screened, Brij$^{(R)}$ 30 provided highest flux of galantamine. Matrix thickness of 80 ${\mu}m$ was optimum for maintaining adhesiveness as well as consistently delivering galantamine for longer period of time.

• Journal of Microbiology and Biotechnology
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• 제19권5호
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• pp.520-524
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• 2009

Two isolates, Bacillus sp. BS87 and RK1, selected from soil in strawberry fields in Korea, showed high levels of antagonism towards Fusarium oxysporum f. sp. fragariae in vitro. The isolates were identified as B. velezensis based on the homology of their gyrA sequences to reference strains. BS87 and RK1 were evaluated for control of Fusarium wilt in strawberries in pot trials and field trials conducted in Nonsan, Korea. In the pot trials, the optimum applied concentration of BS87 and RK1 for pre-plant root-dip application to control Fusarium wilt was $10^5$ and $10^6$ colony-forming units (CFU)/ml, respectively. Meanwhile, in the 2003 and 2005 field trials, the biological control efficacies of formulations of RK1 were similar to that of a conventional fungicide (copper hydroxide) when compared with a non-treated control. The RK1 formulation was also more effective than BS87 in suppressing Fusarium wilt under field conditions. Therefore, the results indicated that formulations of B. velezensis BS87 and RK1 may have potential to control Fusarium wilt in strawberries.