• Journal of the Korean Wood Science and Technology
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• 제42권2호
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• pp.172-182
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• 2014

Extraction is a necessary element in the bioconversion of lignocellulosics to fuels and chemicals. Although various forms of chemical pretreatment of cellulosic materials have been proposed, their effectiveness varies depending on the treatment conditions and substrate. In this study, mixed hardwood (MH) and loblolly pine (LP) were pretreated with dilute acid in a 100 mL accelerated solvent extraction (ASE) at the predetermined optimal conditions: temperature: $170^{\circ}C$, acid concentration: 0.5% (w/v), and reaction time: 2~64 min. This method was highly effective for extracting the hemicellulose fraction. Total xmg (defined as the sum of xylose, mannose, and galactose) can be extracted from milled MH and LP through pressurized dilute acid treatment in maximum yields of 12.6 g/L and 15.3 g/L, respectively, representing 60.5% and 70.4% of the maximum possible yields, respectively. The crystallinity index increased upon pretreatment, reflecting the removal of the amorphous portion of biomass. The crystalline structure of the cellulose in the biomass, however, was not changed by the ASE extraction process.

• 한국수산과학회지
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• 제34권4호
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• pp.320-326
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• 2001

어분단백질의 이용성을 높이기 위한 가식성 혹은 생분해성 필름가공을 목적으로 알칼리 처리하여 제조된 FMPI의 물성과 이물성과 ester 화합물의 필름 투과율과 인장강도에 미치는 영향을 조사한 결과는 다음과 같다. 어분으로부터 알칼리처리하고 추출조건을 달리하여 제조된 FMPI의 추출량은 추출시간이 증가함에 따라 증가하였다. FMPI의 소수성은 추출시간 1시간일 때 가장 높게 나타났다가 그 이상 추출시간이 경과함에 따라 감소하였다 유화활성은 추출시간이 5시간까지 증가함에 따라 급격한 증가를 보였으며, 유화안정성은 추출시간 2시간까지 추출시간의 증가에 따라 급격한 감소를 보여 유화활성과 상반된 결과를 나타내었다. 점도는 pH가 2일 때 가장 높게 나타났고 pH가 4일 때 가장 점도가 낮게 나타났다. 첨가하는 가소제의 농도가 증가할수록 필름의 ethyl acetate의 투과도는 증가하였다. 가소제의 종류별에 따른 ethyl acetate의 투과도는 polyethylene glycol, glycerol 및 sorbitol 첨가 필름 순으로 높게 나타났으며, ester 화합물 중에서는 ethyl formate의 투과속도가 가장 높았다. 온도가 증가함에 따라 ethyl acetate의 필름 투과속도는 증가하였다. FHPI의 표면소수성이 증가하면 필름의 인장강도가 증가하였다. 필름의 신장율은 FMPI의 표면소수성보다 가소제의 종류에 더 큰 영향을 받았다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회(2)
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• pp.1179-1180
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• 2005

To immobilize the pollutants from wastewater in situ, two phosphatic clays collected from different areas in Egypt (eastern and western Sebaia, Aswan-Isna, Upper Egypt) used to remove contaminant ions from industrial wastewater. Obtained results confirmed the strong relationship between phosphatic clay and Pb elimination from wastewater. The sensitivity classification of phosphatic clay toward ions retained as described in three categories: highly sensitive to retain Pb , Al and Cr ; moderately sensitive for Mn; and weakly sensitive for Band Zn. Data suggested that large fraction of Pb removed by phosphatic clays stayed intact under a wide variation in extracting solution pH (3-11). In situ immobilization is considered a promising technique that has the potential to remove contaminant ions from wastewater. Two important factors need to be considered when applying this technique: The first, is the clay must be effective and selective under different composition of wastewater. The second, is the immobilized ions should be stable and non-leacheable under varying water conditions. Phosphatic clays with $Pb^{2+}$ were suitable to achieve these two factors. Possible mechanism for removal $Pb^{2+}$ by phosphatic clays is the formation of fluoropyromorphite through the dissolution of fluoro and hydroxyl apatite by its precipitation from solution, beside, Pb complexation at phosphatic clay surface at P-OH sites.

• Advances in nano research
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• 제9권4호
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• pp.251-261
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• 2020

In this article, vibration attributes of single walled carbon nanotubes based on Galerkin's method have been investigated. The influence of power law index subjected to different end supports has been overtly examined. Application of the Hamilton's variational principal leads to the formation of partial differential equations. The effects of different physical and material parameters on the fundamental frequencies are investigated for armchair and zigzag carbon nanotubes with clamped-clamped, simply supported and clamped-free boundary conditions. By using volume fraction for power law index, the fundamental natural frequency spectra for two forms of Single-Walled Carbon Nanotubes (SWCNTs) are calculated. The influence of frequencies against length-to-diameter ratios with varying power law index are investigated in detail for these tubes. MATLAB software package has been utilized for extracting tube frequency spectra. The obtained results are confirmed by comparing with available literature.

• Ocean and Polar Research
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• 제34권2호
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• pp.265-273
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• 2012

A new algorithm was developed, not only to detect the existence of a thermocline, but also to extract the thermocline parameters (such as thermocline thickness, mixed layer thickness, maximum temperature gradient, and temperature difference of thermocline), using the vertical profile of water temperature. According to Kappa analysis, in order to find adequate threshold values of vertical water temperature gradients ${\Delta}T$ ($^{\circ}C/m$), agreement and reliability were 87% and 0.74 respectively, in the conditions of maximum ${\Delta}T{\geq}0.5$ and surface and bottom layers ${\Delta}T<{\mid}0.2{\mid}$. Also, three different kinds of methods, viz. 1. Gradient method, 2. Hyperbolic tangent method, and 3. Differential hyperbolic tangent method, were tested to extract the key parameters of a thermocline. Comparing the results of three different methods, the differential hyperbolic tangent method was the most appropriate to extract the start and end point of a thermocline curve.

• Animal Bioscience
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• 제35권7호
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• pp.1048-1058
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• 2022

Objective: The present study was to investigate the extraction conditions of dietary fiber from dried cassava pulp (DCP) and cassava distiller's dried grains (CDG) under different NaOH concentrations, and the Fourier transform infrared (FTIR) was used to determine the dietary fiber components. Methods: The dried samples (DCP and CDG) were treated with various concentrations of NaOH at levels of 2%, 4%, 6%, and 8% using a completely randomized design with 4 replications of each. After extraction, the residual DCP and CDG dietary fiber were dried in a hot air oven at 55℃ to 60℃. Finally, the oven dried extracted dietary fiber was powdered to a particle size of 1 mm. Both extracted dietary fibers were analyzed for their chemical composition and determined by FTIR. Results: The DCP and CDG treated with NaOH linearly or quadratically or cubically (p<0.05) increased the total dietary fiber (TDF) and insoluble fiber (IDF). The optimal conditions for extracting dietary fiber from DCP and CDG were under treatment with 6% and 4% NaOH, respectively, as these conditions yielded the highest TDF and IDF contents. These results were associated with the FTIR spectra integration for a semi-quantitative analysis, which obtained the highest cellulose content in dietary fiber extracted from DCP and CDG with 6% and 4% NaOH solution, respectively. The principal component analysis illustrated clear separation of spectral distribution in cassava pulp extracted dietary fiber (DFCP) and cassava distiller's dried grains extracted dietary fiber (DFCDG) when treated with 6% and 4% NaOH, respectively. Conclusion: The optimal conditions for the extraction of dietary fiber from DCP and CDG were treatment with 6% and 4% NaOH solution, respectively. In addition, FTIR spectroscopy proved itself to be a powerful tool for fiber identification.

• 한국식품저장유통학회지
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• 제16권3호
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• pp.400-404
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• 2009

복분자 부산물(박)을 유용한 천연 색소원으로 활용하기 위하여, 복분자 부산물(박)의 추출조건에 따른 색소 및 폴리페놀의 추출 특성에 대해 조사하였다. 용매 조건별 추출한 색소액의 총 흡광도는 80% 에탄올 용매에서 9.51 unit로 높은 편이었고, 폴리페놀은 에탄올 함량이 40%일 때 최고 수율이었고 에탄올 농도가 높아감에 따라 감소하는 경향이었다. 추출액의 총 흡광도는 용매에 citric acid 및 lactic acid를 첨가하였을 때 높았고, 폴리페놀의 함량은 ascorbic acid를 첨가한 용매 조건에서 높았다. 추출조건에서 부산물(박)의 혼합량이 많을수록 부산물(박) 단위 중량에 대한 총 흡광도 및 부산물(박) 단위 중량에 대한 폴리페놀 함량은 감소하는 경향이었으며, 2차례의 추출과정을 반복하였을 때 색소와 폴리페놀은 $85{\sim}90%$ 이상의 추출효율을 나타내었다.

• 한국정보과학회논문지:소프트웨어및응용
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• 제34권11호
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• pp.991-1000
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• 2007

본 논문에서는 단일 프레임의 교통 영상에서 차량을 검출하는 새로운 기법을 제안한다. 제안하는 기법은 동작 환경에 관계없이 여러 형태로 분류된 그림자를 추출한다. 차량의 색상과 조명 조건에 관계없이 차량이 도로와 접한 부분에는 어두운 그림자 형상을 가진다는 사실을 이용하여 그림자 분류를 수행한다. 추출된 그림자는 차량의 존재 유무를 판단할 강력한 능력을 가지고 있으며, 배경 영상과 다른 시간적 정보들을 이용하지 않으므로, 기상 및 교통 정체가 빠르게 변화하는 상황에서도 높은 검출 성능을 보장한다. 차량 위치에 존재하는 자은 정보와 그림자 영역과의 간단한 증거 추론 기법에 의해 차량을 검출할 수 있다. 6개의 다른 동작 환경의 실험에서 4% 이하의 오검출율을 보이고, 0.9%에서 7.2%의 미검출율을 보였다. 또한, 작은 크기의 영상에 대해 초당 70 프레임 이상의 처리가 가능하므로, 다양한 교통 정보를 실시간으로 측정하는 기법에 사용될 수 있다.

• Journal of Mechanical Science and Technology
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• 제18권9호
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• pp.1537-1548
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• 2004

This paper presents a novel diagnostic technique for monitoring the system conditions and detecting failure modes and precursors based on wavelet-packet analysis of external noise/vibration measurements. The capability is based on extracting relevant features of noise/vibration data that best discriminate systems with different noise/vibration signatures by analyzing external measurements of noise/vibration in the time-frequency domain. By virtue of their localized nature both in time and frequency, the identified features help to reveal faults at the level of components in a mechanical system in addition to the existence of certain faults. A prima-facie case is made via application of the proposed approach to fault detection in scroll and rotary compressors, although the methods and algorithms are very general in nature. The proposed technique has successfully identified the existence of specific faults in the scroll and rotary compressors. In addition, its capability of tracking the severity of specific faults in the rotary compressors indicates that the technique has a potential to be used as a prognostic tool.

• Computers and Concrete
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• 제25권5호
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• pp.411-425
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• 2020

In this paper, the shell material has been taken as functionally graded material and their material quantity is located by the exponential volume fraction law. Moreover, the impact of ring supports around the shell circumference has been examined for their various positions along the shell axial length. These rings support restraints the radial displacement in the transverse direction. While the axial modal deformation functions have been estimated by characteristic beam functions and nature of materials used for construction of cylindrical shells. The fundamental natural frequency of cylindrical shell of parameter versus ratios of length- and height-to-radius for a wide range has been reported and investigated through the study. In addition, by increasing height-to-radius ratio resulting frequencies also increase and frequencies decrease on ratio of length-to-radius. Though the trends of frequency values of both ratios are converse to each other with three different boundary conditions. Also it is examined the position of ring supports with length-to radius ratio, height-to-radius ratio and varying the exponent of volume fraction. MATLAB software package has been utilized for extracting shell frequency spectra. The obtained results are confirmed by comparing with available literature.