• Journal of Korean Society of Environmental Engineers
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• v.22 no.7
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• pp.1273-1284
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• 2000

In this study, ultrafiltration was performed to remove humic acid from aqueous solution. Since the effects of system variables on the ultrafiltration were tangled with non-linearly. Response Surface Methodology(RSM) was used to know optimum conditions of ultrafiltration process, relations among system variables, and the effects of system variables such as pressure difference across the membrane, concentration of humic acid, and feed flow rates. As concentrations of humic acid were 10ppm, 40ppm, and 70ppm in feed stream, permeation fluxes were 2.56, 2.27, and $2.10({\times}10^{-2}cc/cm^2{\cdot}min)$ respectively ; in other words, permeation fluxes of 10ppm, 40ppm and 70ppm feed concentration decreased by 17.7%, 26.7% and 32.2% of pure water permeation flux respectively. Concentration of humic acid in permeate side were 0.5ppm, 1.2 ppm, and 2.1ppm respectively. When pressure difference(${\Delta}P$) increased from 1atm to 2atm and 3atm, permeation fluxes of 40ppm feed concentration increased by 66% and 152% of permeation rate at 1atm respectively. However, concentrations of humic acid in permeate side increased from 0.5ppm to 1.5ppm and 3.5ppm. RSM showed that the optimum condition of system variables is 38.5~40ppm of humic acid concentration in feed stream, 30~30.7cc/min of feed flow rate, and 2atm of pressure difference.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.04a
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• pp.119.1-119
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• 2003

단체 급식의 증가와 더불어 편의식품을 선호하는 소비 경향에 맞추어 최소가공한 과일의 갈변저해를 위한 저해제를 탐색하였다. 실험에 사용한 과일은 배와 감으로 각각 박피하여 속심을 제거한 후 배는 8조각으로 절단하고 감은 1~2cm 두께로 slice 하였다. 저해제는 1% ascorbic acid, citric acid, NaCl, MgCl$_2$, CaCl$_2$, oxalic acid, EDTA, raffinose, salicylic acit, sporix를 사용하였다. 또한 열수 추출한 오약, 계피, 황기, 당기, 건칡, 진피, 천궁, 감초 등도 저해제로 사용하였다. 최소가공한 과일은 저해제에 3분간 침지한 후 물기를 제거하고 tray에 포장하여 실온에서 저장하면서 colorimeter를 이용하여 갈변도의 변화를 측정하였다. 갈변 정도를 나타내는 $\Delta$E 는 시간의 경과에 따라 점차 감소하는 경향을 보였으나 배의 경우 변화 정도가 크지 않았다. NaCl, MgCl$_2$, CaCl$_2$를 처리한 배의 갈변 정도가 가장 적었다. cysteine을 처리한 구에서는 황화합물 냄새가 났다. 또한 oxalic acid를 처리한 구에서는 연화가 빠르게 일어났으며 저장 시간이 경과함에 따라 수분이 용출되었다. 한약재는 자체 색으로 인해 배의 색변화를 증가시켰으며 이취가 발생했다. 또한 저장 시간이 경과함에 따라 건조가 빠르게 일어나 관능적으로도 좋지 않은 결과를 나타냈다. 감에서는 CaCl$_2$, MgCl$_2$를 처리한 구에서 색의 변화가 가장 적었으며 cysteine은 색변화는 적었으나 배의 경우과 같이 이취가 발생하였다. 한약제는 계피와 진피를 처리한 감에서 색의 변화를 저해하는 효과를 보였다.를 처리하였을 경우 당귀, 천문동을 처리한 구에서 효과를 보였다. oxalic acid는 갈변저해에는 효과적이었으나 시간이 경과함에 따라 수분의 용출이 증가하였으며 물성의 변화도 컸다. 또한 ZnCl$_2$를 처리한 구에서는 이취 발생과 수분 용출이 컸으며 색의 변화도 컸다.내었다. 고온 단시간 처리구의 경우 저온 장시간 처리구와는 달리 저장 1일 후부터 그 농도가 다소 상승되었다가 다시 감소는 경향을 보였다. 한편 열처리하여 냉각시킨 직후 및 저장1주 후 사과의 pH, 산도, 당도, 경도, 과육의 갈변도 등을 조사하였던 바 대조구 및 처리구간에 일부 항목에 있어서는 약간의 차이를 나타내었다. 대치할 수 있을 것이라고 사료된다. 수분함량은 기계적 검사보다 관능검사와 더욱 높은 상관관계를 나타냈다.내었다. 항균활성이 우수한 생약재를 농도별로 활성을 조사한 결과, 물 추출물과 10% Ethanol 추출물 모두 낮은 농도에서도 우수한 항균활성을 나타내었다.취와 함께 점질성 갈변물질이 생성되었다. 이와 같은 결과로 볼 때, BAAG의 처리는 BAAC의 경우보다 가격은 저렴하면서도 항균력은 우수한 천연 항균복합제재로써 농산물 식품원료에 적용하여 선도유지 기간을 연장할 수 있는 효과를 기대할 수 있었다. 과일 등의 포장제로서 이용할 가능성을 확인하였다.로 [-wh] 겹의문사는 복수 의미를 지닐 수 없 다. 그러면 단수 의미는 어떻게 생성되는가\ulcorner 본 논문에서는 표면적 형태에도 불구하고 [-wh]의미의 겹의문사는 병렬적 관계의 합성어가 아니라 내부구조를 지니지 않은 단순한 단어(minimal $X^{0}$ elements)로 가정한다. 즉, [+wh] 의미의 겹의문사는 동일한 구성요 소를 지닌 병렬적 합성어([$[W1]_{XO-}$ $[W1]_{XO}$ ]

• Computers and Concrete
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• v.14 no.5
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• pp.599-612
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• 2014

This paper presents the effects of the construction stages using time dependent material properties on the structural behaviour of concrete arch dams. For this purpose, a double curvature Type-5 arch dam suggested in "Arch Dams" symposium in England in 1968 is selected as a numerical example. Finite element models of Type-5 arch dam are modelled using SAP2000 program. Geometric nonlinearity is taken into consideration in the construction stage analysis using P-Delta plus large displacement criterion. In addition, the time dependent material strength variations and geometric variations are included in the analysis. Elasticity modulus, creep and shrinkage are computed for different stages of the construction process. In the construction stage analyses, a total of 64 construction stages are included. Each stage has generally $6000m^3$ concrete volume. Total duration is taken into account as 1280 days. Maximum total step and maximum iteration for each step are selected as 200 and 50, respectively. The structural behaviour of the arch dam at different construction stages has been examined. Two different finite element analyses cases are performed. In the first case, construction stages using time dependent material properties are considered. In the second case, only linear static analysis (not considered construction stages) is taken into account. Variation of the displacements and stresses are obtained from the both analyses. It is highlighted that construction stage analysis using time dependent material strength variations and geometric variations has an important effect on the structural behaviour of arch dams. The maximum longitudinal, transverse and vertical displacements obtained from construction stages and static analyses are 1.35 mm and 0 mm; -8.44 and 6.68 mm; -4.00 and -9.90 mm, respectively. In addition, vertical displacements increase from the base to crest of the dam for both analyses. The maximum S11, S22 and S33 stresses are obtained as 1.60MPa and 2.84MPa; 1.39MPa and 2.43MPa; 0.60MPa and 0.50MPa, respectively. The differences between maximum longitudinal, transverse, and vertical stresses obtained from construction stage and static analyses are 78%, 75%, and %17, respectively. On the other hand, there is averagely 12% difference between minimum stresses for all three directions.

• Proceedings of the Korean Magnestics Society Conference
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• 2011.06a
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• pp.7-8
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• 2011

Basically, the lattice mismatch between film and substrate can make those BiFeO3(BFO) films distorted with strain structure. BFO phase can be stabilized on LaAlO3(LAO) represents the example of a multiferroic with giant axial ratio. Its crystal structure is not strictly tetragonal, but tetragonal with a slight monoclinic distortion and related to the rotation of the oxygen octahedra. In this study, we show that phases with a tetragonal-like epitaxial BFO films can indeed be ferroelectric and also can be stabilized via epitaxial growth onto LAO. Recent reports on epitaxial BFO films show that the crystal structure changes from nearly rhombohedral ("R-like") to nearly tetragonal("T-like") at strains exceeding approximately -4.5%, with the "T-like" structure being characterized by a highly enhanced c/a ratio. While both the "R-like" and the "T-like" phases are monoclinic, our detailed x-ray diffraction results reveal asymmetry change from MA and MC type, respectively. By applying additional strain or by modifying the unit cell volume of the film by substituting Ba for Bi, the monoclinic distortion in the "T-like" MC phase is reduced, i.e. the system approaches a true tetragonal symmetry. There are two different M-H loops for $Bi_{1-x}Ba_xFeO_{3-{\delta}}$(BBFO) and BFO films on SrTiO3(STO) & LAO substrates. Along with the ferroelectric characterization, these magnetic data indicate that the BFO phase stabilized on LAO represents the first example of a multiferroic with giant axial ratio. However, there is a significant difference between this phase and other predicted ferroelectrics with a giant axial ratio: its crystal structure is not strictly tetragonal, but tetragonal with a slight monoclinic distortion. Therefore, in going from bulk to highly-strained films, a phase sequence of rhombohedral(R)-to-monoclinic ["R-like" MA-to-monoclinic, "T-like" MC-to-tetragonal (T)] is observed. This sequence is otherwise seen only near morphotropic phase boundaries in lead-based solid-solution perovskites (i.e. near a compositionally induced phase instability), where it can be controlled by electric field, temperature, or composition. Our results show that this evolution can occur in a lead-free, stoichiometric material and can be induced by stress alone. Those major results are summarized as follows ; 1) Ba-doping increases the unit cell volume, 2) BBFO on LAO can be fully strained up to x=0.08 as a strain limit (Fig. 1), 3) P(E) & M(H) properties can be tuned by the variation of composition, strain, and film thickness.

• Korean Chemical Engineering Research
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• v.52 no.3
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• pp.314-320
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• 2014

Regarding the design of the gas sweetening absorber, the gas distribution analysis for the increase of the sour gas removal and reduction of the tower height is very important research topics. Recently, regarding the $CO_2$ capture technology which is a promising option for the reduction of the greenhouse gas (GHG), the need for the gas distribution improvement is increased as the gas treating capacity increases. In this paper, we have investigated the sour gas distribution in the absorber using CFD (Computational Fluid Dynamics) based on 10 MW post-combustion $CO_2$ capture plant installed in Boryeong power station, Korea Midland Power company. For this purpose, we suggested the three possible technology options (splash plate, spiral gas line and U-tube) for the gas distribution enhancement and compared the effect of the each cases. The result showed that the U-tube installed in the absorber increase the gas distribution about 30% compared to the base case, while the delta P increasement was about 10%. From these results, it was found that the U-tube installation is an effective technology option for the gas distribution enhancement in the gas sweetening absorber.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.10
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• pp.1179-1185
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• 2011

Cold and hot-rolled carbon steel sheets are commonly used in railroad cars or commercial vehicles such as the automobile. The sheets used in these applications are mainly fabricated by spot welding, which is a type of electric resistance welding. However, the fatigue strength of a spot-welded joint is lower than that of the base metal because of high stress concentration at the nugget edge of the spot-welded part. In particular, the fatigue strength of the joint is influenced by not only geometrical and mechanical factors but also the welding conditions for the spot-welded joint. Therefore, there is a need for establishing a reasonable criterion for a long-life design for spot-welded structures. In this thesis, ${\Delta}P-N_f$ relation curves have been used to determine a long-life fatigue-design criterion for thin-sheet structures. However, as these curves vary under the influence of welding conditions, mechanical conditions, geometrical factors, etc. It is very difficult to systematically determine a fatigue-design criterion on the basis of these curves. Therefore, in order to eliminate such problems, the welding residual stresses generated during welding and the stress distributions around the weld generated by external forces were numerically and experimentally analyzed on the basis of the results, reassessed fatigue strength of gas welded joints.

• Korean Journal of Weed Science
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• v.32 no.3
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• pp.204-210
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• 2012

The physicochemical properties of tuber starch in water chestnut have been studied. Peak viscosity, hot paste viscosity and cooling peak viscosity were 5679, 3146 and 4262 RVU, respectively. In three transition parameters, onset temperature ($T_o$), peak temperature ($T_p$), and conclusion temperature ($T_c$) were 64.1, 68.5 and $72.3^{\circ}C$, respectively. Gelatinization enthalpy (${\Delta}H$ gel) was 4.48 J/g. A-type starch has a smaller proportion (11.4%) of short chains ($DP{\geq}12$) and a larger proportion (57.2%) of short chains ($13{\leq}DP{\geq}24$). The tuber starch of water chestnut displayed an A-type X-ray diffraction pattern showing a strong diffraction peak at $2{\Theta}$ values of $15.18^{\circ}$, $17.13^{\circ}$, and $23.1^{\circ}$, and a weak peak at $2{\Theta}$ values of $18.1^{\circ}$, $20.06^{\circ}$, and $26.69^{\circ}$. Their crystallinity was 28.6% and the mean starch granule size was 21.5 ${\mu}m$.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.10
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• pp.1565-1574
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• 2018

Objective: The aim of the present study was to identify genetic variants based on RNA-seq data, obtained via transcriptome sequencing of muscle tissue of pigs differing in muscle histological structure, and to verify the variants' effect on histological microstructure and production traits in a larger pig population. Methods: RNA-seq data was used to identify the panel of single nucleotide polymorphisms (SNPs) significantly related with percentage and diameter of each fiber type (I, IIA, IIB). Detected polymorphisms were mapped to quantitative trait loci (QTLs) regions. Next, the association study was performed on 944 animals representing five breeds (Landrace, Large White, Pietrain, Duroc, and native Puławska breed) in order to evaluate the relationship of selected SNPs and histological characteristics, meat quality and carcasses traits. Results: Mapping of detected genetic variants to QTL regions showed that chromosome 14 was the most overrepresented with the identification of four QTLs related to percentage of fiber types I and IIA. The association study performed on a 293 longissimus muscle samples confirmed a significant positive effect of transforming acidic coiled-coil-containing protein 2 (TACC2) polymorphisms on fiber diameter, while SNP within forkhead box O1 (FOXO1) locus was associated with decrease of diameter of fiber types IIA and IIB. Moreover, subsequent general linear model analysis showed significant relationship of FOXO1, delta 4-desaturase, sphingolipid 1 (DEGS1), and troponin T2 (TNNT2) genes with loin 'eye' area, FOXO1 with loin weight, as well as FOXO1 and TACC2 with lean meat percentage. Furthermore, the intramuscular fat content was positively associated (p<0.01) with occurrence of polymorphisms within DEGS1, TNNT2 genes and negatively with occurrence of TACC2 polymorphism. Conclusion: This study's results indicate that the SNP calling analysis based on RNA-seq data can be used to search candidate genes and establish the genetic basis of phenotypic traits. The presented results can be used for future studies evaluating the use of selected SNPs as genetic markers related to muscle histological profile and production traits in pig breeding.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.3
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• pp.378-382
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• 2006

Clarified orange juice was prepared using different clarification methods including centrifugation, enzyme treatment, ultrafiltration (UF), and combined treatment(CT). Effect of clarification methods as well as other quality parameters were investigated. Clarification was improved with increase in centrifugation speed and by lowering operating temperature. The optimum condition for centrifugation process was $5^{\circ}C$ and 10,000 rpm. UF and CT processes were very effective to produce clarified orange juice. The optimum condition of UF process was $45^{\circ}C$ and 150 kPa considering flux and turbidity CT did not significantly improve the clarification efficiency since most of the clarification was already achieved during UF process. $L^*$-values increased while $a^*$-values decreased significantly after clarification regardless of methods (p<0.05) Considering color, and recovering rate of vitamin C and soluble solids, UF process was superior than the other methods in producing clarified orange juice.

• Korean Journal of Food Science and Technology
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• v.25 no.5
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• pp.546-551
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• 1993

Rice flour obtained by four different milling methods, Pin mill. Colloid mill, Micro mill, and Jet mill, were used to investigate physico-chemical properties and product. Crude fat, ash, and protein contents of rice flours between different milling methods were similar. Blue value, amylose content, and damaged starch which related to properties of rice flour were reduced in the order that of Jet mill, Micro mill, Colloid mill, and Pin mill. Water absorption index, water solubility index, and water retention capacity increased as damaged starch increased. Hardness of gel(15%) is the highest value for Pin mill. The finer granules (Jet mill) had lower gelatinization onset(To) and peak(Tp) than any other rice flours. Those result are simillar with amylogram properties. Enthalpy of gelatinization increased as damaged starch increased. Jet mill had the highest score (p<0.05) of overall test in sensory evaluation and good paste properties.