• Journal of the Korea institute for structural maintenance and inspection
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• v.9 no.3
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• pp.111-119
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• 2005

The objective of this study is to predict fracture movements accurately and reliably by nonlinear analysis of the response of RC shear wall or RC flange sections. Hognestad's and Vallenas's theories are used for concrete model and Ramberg-Osgood's theory is used for steel model. Non-linear analysis considering confined concrete and unconfined concrete is performed. Mander's Fiber Approach Section analysis, new strain profile considering the Gamma factor are used to this section analysis. The section analysis considering cases of precracked, uncracked, boundary warping and shear warping is performed.

• Transactions of Materials Processing
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• v.13 no.8
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• pp.723-730
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• 2004

This paper describes the analysis of extrusion process and integrity for a condenser tube which is a component of the heat exchanger in automobile and all conditioning apparatus. Recently, according to the development of analysis method using the computer, the numerical simulation have been applied to the 3-dimensional hot extrusion process with complex section area of the non-steady statement and then results of the analysis have been applied to optimal die design and process design. In this paper, firstly, the die design was performed for a condenser tube with a multi-hole section and the rigid-plasticity FE analysis performed of extrusion process. Secondly, we estimated metal flow of billet, extrusion load, welding pressure in chamber etc. and evaluated the pressure and elastic strain of the die land and mandrel tooth profile through a stress analysis of the die. Finally, the extrusion test was performed to estimate the validity of FE analysis. This paper confirmed that the designed extrusion die of the research is satisfactorily designed fur integrity of condenser tube.

• Journal of Microbiology
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• v.41 no.4
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• pp.327-334
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• 2003

This study employed two PCR-based 16S rDNA approaches, amplified rDNA restriction analysis (ARDRA) and denaturing gradient gel electrophoresis (DGGE), to characterize the bacterial community structure in groundwater. Samples were collected from groundwater for the use by private residences, as well as for industrial and agricultural purposes, in Ansan City. Each PCR product was obtained by PCR with eubacteria 16S rDNA and variable V3 region specific primer sets. After amplification, the 16S rDNA PCR products were digested with 4-base site specific restriction endonucleases, and the restriction pattern analyzed. The genetic diversity and similarity of the groundwater bacterial community was analyzed by eubacteria universal primer sets for the amplification of variable V3 regions of the bacterial 16S rDNA. The result of the bacterial community analysis, by ARDRA and DGGE, revealed the same pattern. The highest diversity was found in groundwater from site G1, which was used in residences. In the DGGE profile, a high intensity band was sequenced, and revealed to be Pseudomonas sp. strain P51.

• Preventive Nutrition and Food Science
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• v.2 no.2
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• pp.101-108
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• 1997

A lactic acid bacterium LAB3113, isolated from traditionally fermented Kimchi was found to produce bacteriocin whose activity was very specific toward lactobacilli and not effective against any other bacteria. Lactobacilli affected by the inhibitory substance included Lactobacillus delbrueckii-lactis, L. johnsonii, L. gsseri, and L. curvatus. Based upon biochemical and physiological characteristics, LAB3113 was classified as Lactococcus lactis, and its bacteriocin was named as lactococcin K3113. Lactococcus lactis. LAB3113 produced bacteriocin at th early stage of growth and the concentration of the bacteriocin did not decrease even after alt stationalry phase. Optimal temperature of bacteriocin production was $25^{\circ}C$ at the initial pH 7.0. Partially purified lactococcin K3113 was completely inactivated by protease, but not affected by lipase, lysozyme and RNase. The bacteriocin was very heat-stable even after autoclaving for 20 min. It was also stable in pH changes, an was not affected by th presence of solvents. lacotococcin K3113 appeared to act in bactericidal mode against L. delbrueckii-lactis ATCC4797. Molecular weight of lactococcin K3113 was calibrated as 10,500 dal by SDS-PAGE an activity staining. Lactococcus lactis LAB3113 had four residential plasmids of 3.7kb, 11.2kb, 15.5kb, and 48kh in molecular sizes. Plasmid profile analysis of mutant strain revealed that 15.5 kb plasmid was re-sponsible for the production of lactococcin K3113 and its immunity to the bacteriocin.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.6
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• pp.1077-1085
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• 1997

This study was carried out to elucidate the utilization of the fusant for shortening the ripening time by making an observation of the microstructure and the profile of component change. In ripening cheese, moisture content of the sample treated with tested strain is not a remarkable difference among the test samples. With an increase of the ripening time, L. helveticus showed the highest increase in protein content, followed by fusant, and then L. bulgaricus. The fat content of all starters was gradually decreased while it was it was rapidly decreased after 7 days. The pH of all starters was gradually decreased when the ripening time increased. The titratable acidity was greatly increased between a 9th day and a 15th day ripening. In investigating the light microscopic microstructure of ripened cheese samples, the sample treated with fusant indicated little difference from the other starters in decomposition of protein and fat components by microbial enzymes. In SEM observation, the structure of all cheese samples was uniform and the rough texture was converted into smooth texture by the interaction of cheese components and the abscission of single bond in casein matrix when the ripening time is increased. The fusant showed similar results in the examination of component change and its microstructure compared with the other starters. Therefore, it was revealed that the fusant can be partially used as a cheese starter instead of conventional starters by replacing them or combining them together with the other starters for shortening the ripening time.

• Journal of Applied Biological Chemistry
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• v.61 no.4
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• pp.327-334
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• 2018

Monascus is a source of food colorant with high productivity of the pigment azaphilone. Monascus azaphilone (MAz) is biosynthesized through a single non-reducing polyketide pathway, the major components of which are ankaflavin (1), monascin (2), rubropunctatin (3) and monascorubrin (4); valuable biological activities have been reported for these compounds. Thus, various culture conditions were explored to reduce the cost of culture ingredients, enhance productivity and modulate compound composition. In the present study, we examined an extractive fermentation (EF) method with Diaion HP-20 resin (HP20) in direct comparison to a previously explored method involving Triton X-100 (TX100) to explore the modulated production of the major MAzs. We employed wild-type Monascus purpureus as well as two derivative recombinant strains (${\Delta}mppG$ and ${\Delta}mppE$) that are known to have differential MAz profiles as that of the wild-type strain. The HP20 resin was capable of modulating the MAz profile in favor of orange MAzs 3 and 4, oxidized congeners in this class, as was TX100-a phenomenon not previously observed for TX100 EF with Monascus anka. These finding substantiate that HP20 can be employed for the selective production of oxidized MAz and for diversifying the culture conditions used for Az production.

• Structural Engineering and Mechanics
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• v.81 no.4
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• pp.523-527
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• 2022

The objective of this study is to simulate the flow in pipes with various boundary conditions. Free-pressure fluid model, is used in the pipe based on Navier-Stokes equation. The models are solved by using the numerical method. A problem called "stability of pipes" is used in order to compare frequency and critical fluid velocity. When the initial conditions of problem satisfied the instability conditions, the free-pressure model could accurately predict discontinuities in the solution field. Employing nonlinear strains-displacements, stress-strain energy method the governing equations were derived using Hamilton's principal. Differential quadrature method (DQM) is used for obtaining the frequency and critical fluid velocity. The results of this paper are analyzed by hyperbolic numerical method. Results show that the level of numerical diffusion in the solution field and the range of well-posedness are two important criteria for selecting the two-fluid models. The solutions for predicting the flow variables is approximately equal to the two-pressure model 2. Therefore, the predicted pressure changes profile in the two-pressure model is more consistent with actual physics. Therefore, in numerical modeling of gas-liquid two-phase flows in the vertical pipe, the present model can be applied.

• Journal of Mushroom
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• v.14 no.2
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• pp.64-69
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• 2016

Pleurotus eryngii is one of the most widely cultivated and important edible mushrooms. However, the shelf life of the fruiting body is short, which. To solve this problem, a new cultivar, DanBi 5Ho, of Pleurotus eryngii was developed by mono-mono crossing between monokaryotic strains derived from KNR2598 and KNR2610. The optimum temperature formycelial growth was 25 and that forfruiting body development was 15-16. The quality did not change after a period of 40.0 d at 4. This result was significantly different compared to that ofthe control strain Knneuari 2 Ho. Analysis of genetic characteristics of the new hybrid strain DanBi 5Ho revealeda different profile thanthat of the parental and control strains when random amplification of polymorphic DNA (RAPD) primers we used. The results obtained from this study show that DanBi 5Ho is a new hybrid strain, characterized by improved storability after harvesting.

• Transactions of the KSME C: Technology and Education
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• v.3 no.2
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• pp.83-88
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• 2015

Agricultural tractors are utilized on rough road such as rice paddy field. Therefore, static and dynamic load should be considered when simulating structural analysis with finite element analysis (FEA). But it consumes a lot of time and effort to measure dynamic load because of difficulty and complexity in modeling various field working load conditions and kinematics of machinery. In this paper, to reduce the efforts, 4-post road simulator is developed for agricultural tractor like modeling commercial vehicle. In proving ground test in our facility, I measured acceleration of front/rare axle and strain of body frame to validate input loads. The acceleration is used for defining input loads. And strain is validated with dynamics analysis including mode superposition method. As a result, I was able to calculate 4-post input road profiles, which represent similar proving ground profile with good reliability.

• Food Science of Animal Resources
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• v.29 no.5
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• pp.640-646
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• 2009

Lactic acid bacteria (LAB) are typical probiotic microbes that are used in various industries including fermented foods, feed additives, and pharmaceuticals. The purpose of this study was to compare the ability of isoflavone biotransformation and antioxidative activity of 17 LAB. Six strains including the Lactobacillus species exhibited a 100% hydrolysis rate for daidzein during fermentation. The content of total genistein in soymilk fermented with these strains was $872-943\;{\mu}g/g$. The DPPH (1, 1-diphenyl-2-picrylhydrazyl) radical scavenging ability of the LAB was widely variable and ranged from 23-78%. A selected strain was isolated from kimchi and the strain was identified as Lactobacillus plantarum ssp. through the API carbohydrate fermentation pattern and 16S rDNA profile. The strain exhibited excellent acid tolerance in an artificial gastric solution. L. plantarum YS712 showed high $\beta$-glucosidase activity in fermentation. The concentration of genistein and daidzein in soymilk fermented with L. plantarum YS712 increased from 3.64 to $917.3\;{\mu}g/g$ and from 58.18 to $1062.17\;{\mu}g/g$, respectively. These results demonstrate the potential of L. plantarum YS712 as a probiotic culture that can be utilized in the manufacturing of fermentation foods and dietary supplements.