• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.3
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• pp.506-513
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• 1992

본 연구에서는 복합재 구조물에 대하여 유한요소해석법에 현상학적 모델인 전 단지연해석을 도입하여 강성저하와 모재파손을 예측하고 변형률을 매개변수로 한 Wei- bull 함수를 섬유파손해석에 도입하여 초기파손후의 거동을 묘사하고자 한다. 그리 고 면내전단하중이 작용하는 경우에 대해 전단지연해석을 수행할 수 있도록 모델링을 확장했다. 모재균열의 존재로 인한 단층의 강성변화는 실험으로 측정이 불가능하므 로 유한요소해석을 수행하여 비교하였다. 이 모델로부터 전단강성의 저하를 평가하 는 방법을 사용하였으며, 모재파손의 밀도 예측도 평균변형률 개념으로 전단효과를 고 려할 수 있도록 수정하였다. 그리고 초기파손후의 거동을 점진적으로 해석하기 위해 비선형 유한요소프그램을 작성하고, 상기의 모델을 도입하여 초기파손후의 거동을 보 다 정확히 묘사할 수 있는 방법을 제시하고 예로서 평시편에 대해 해석하고 실험치 및 타방법의 결과와 비교하였다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.3
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• pp.143-151
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• 2006

This paper presents the comparison of the goodness-of-fit test of analytical bond models between concrete and steel or GFRP reinforcements. Bond test specimens were prepared in accordance with the CSA codes and the rebars used in the test were steel and two types of commercial GFRP rebar products. Using the test data, a bond model was proposed, and comparison of goodness-of-fit test for existing bond models and proposed bond model was carried out by the least squares method. The result indicates that the proposed bond model has better goodness-of-fit test than the existing ones.

• Journal of Veterinary Clinics
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• v.30 no.6
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• pp.403-408
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• 2013

The objective of the present study is to detect the effect of ${\beta}$-glucan originated from Aureobasidium on the proliferation and collagen production in human dermal fibroblast cells with wound repopulation in vitro. The proliferative effects were assessed using a MTT assay as well as cell counts at 24 and 48 hr after treatment. Hydroxyproline was measured as an index of procollagen production with reverse-phase high pressure liquid chromatography. Oncostatin M was used as a reference agent. In glucagon treated group, dose-dependent and significant increase of optical density or fibroblast cell numbers was demonstrated, when compared with those of control from 0.1 mg/ml concentration. In addition, the numbers of cells which had migrated into the wound defects were more significantly and dose-dependently increased than those of non-treated control. However, no meaningful effects on the procollagen production were observed.

• Food Science and Preservation
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• v.12 no.6
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• pp.608-612
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• 2005

Fourier transform-near infrared (FT-NIR) spectroscopy is a simple, rapid, non-destructive technique which can be used to make quantitative analysis of chemical composition in grain. An interest in total dietary fiber (TDF) of grain such as rice has been increased due to its beneficial effects for health. Since measuring methods for TDF content were highly depending on experimental technique and time consumptions, the application of FT-NIR spectroscopy to determine TDF content in milled rice. Results of enzymatic-gravimetric method were $1.17-1.92\%$ Partial least square (PLS) regression on raw NIR spectra to predict TDF content was developed Accuracy of prediction model for TDF content was certified for regression coefficient (r), standard error of estimation (SEE) and standard error of prediction (SEP). The r, SEE and SEP were 0.9705, 0.0464, and 0.0604, respectively. The results indicated that FT-NIR techniques could be very useful in the food industry and rice processing complex for determination of TDF in milled rice on real time analysis.

• Composites Research
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• v.33 no.4
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• pp.220-227
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• 2020

When curing the composite, the fibers have little thermal deformation, but the resin changes its properties with time and temperature, which leads to residual stress in the product. Residual stress is caused by the difference in the coefficient of thermal expansion of the fibers and resin during the curing process and the chemical shrinkage of the resin. This difference causes thermal deformation such as spring-in and warpage. Thermal deformation of composite structure is important issue on quality of product, and it should be considered in manufacturing process. In this study, a subroutine was developed to predict thermal deformation by applying 3-D viscoelastic model. The finite element analysis was verified by comparing the results of the plate analysis of the 2-D viscoelastic model. Spring-in of L-shaped structure was predicted and analyzed by applying the 3-D viscoelastic model.

• Korean Journal of Food Science and Technology
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• v.38 no.2
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• pp.165-168
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• 2006

Fourier transform-near infrared spectroscopy (FT-NIRS) was evaluated for determination of total dietary fiber (TDF) content of brown rice. Enzymatic-gravimetric method was suitable to obtain reference values for calibration of NIR at 1,000-2,500 nm range. Standard error of laboratory procedure ranged 0.17 to 0.72%. Partial least square (PLS) regression was used to develop the calibration equations. Regression was performed automatically using NIRCal chemometric software. Accuracy of prediction model for TDF content was certified for regression coefficient (r), standard error of estimation (SEE) and standard error of prediction (SEP), showing 0.9780, 0.0636, and 0.0642, respectively. This prediction model can be used for determination of TDF in brown rice and would be useful for real-time analysis in food industry.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.939-941
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• 2017

The use of composites is increasing for lightweight aerospace structures. Among these structures, the ring frame and the parts of the projectile body are mainly made of a fiber reinforced composite material which is less susceptible such as delamination to structural damage. As the use of fiber reinforced composites increases, interest in modeling efficient methods of stiffness and strength is increasing. This paper predict the mechanical strength according to the repeating unit cell(RUC) of the 2-D triaxial braided composites of fiber reinforced composites. Yarn slice definition, incremental approach and stiffness reduction model were used as strength prediction. Finally, the results of strength prediction are verified by comparing with experimental data of 2-D triaxial braided composites specimens.

• Elastomers and Composites
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• v.47 no.4
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• pp.310-317
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• 2012

A jute fiber surface was modified with argon gas in a cylinder type RF plasma generator to enhance the interfacial bond strength and to optimize the plasma treatment condition. The plasma power, gas pressure, and treat time were varied to figure out any effect of those parameters on the morphology and mechanical strength of jute fibers, and the interfacial bond strength for a model composite with polypropylene resin. As the severity of plasma treatment was increased, the surface of jute fibers became rougher. Gas pressure was less effective in roughening of the surface compared with those of treat time and plasma power. Approximately 25% drop in tensile strength of jute fibers was observed for the parameters of treat time and plasma power, while little deterioration was found for gas pressure, with increasing the severity. Based on the interfacial shear strength (IFSS), the optimum plasma treatment condition was determined to be treat time of 30 s, plasma power of 40 W, and gas pressure of 30 mTorr.

• Journal of the Korean GEO-environmental Society
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• v.9 no.2
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• pp.67-74
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• 2008

Many industrialized countries of the world have many problems about the reuse of waste landfill area because of the increase of terminated waste disposal landfill. Especially, the effective use of the terminated waste disposal landfill nearby the urban area has been demanded, because of the lack of the usable land. However, in case of the construction of the building on such a landfill, ground settlement and reduced bearing capacity would be occurred without ground stabilization and proper reinforcement. This study is to evaluate the applicability of geosynthetics for the increment of bearing capacity of solid waste landfill ground. A numerical simulation has been undertaken to model a layer of weathered soil overlaying a layer of geosynthetic reinforcement and waste disposal ground. The proposed analytical model can be used to obtain surface settlement characteristic in the two-dimensional deformation related reinforcement.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.6
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• pp.1381-1387
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• 2007

Up to now, various continuous-processing systems are used in many industrial applications such as textile machines, paper-making machines, printing machines, and so on. In these applications, the tension forced on the products in the control volume can be changed according to the velocity difference between the feeding roll and the delivery roll. Specially, the tension variation generated by the velocity difference, or the inertial effect can decreases the quality of the products in the textile process. In this paper, the tension control problem in a circular knitting machine system is treated to cope with these problems. Firstly, the tension relationship in the winding mechanism of general continuous-processing systems is modeled. Next, to effectively drive the feeding and delivery rolls in the circular knitting machine system, a new tension control method is presented by considering the inertia compensation and the velocity difference between the feeding roll and the delivery roll. Through the experimental works, it is shown that the proposed tension control method can be used to improve the performance of tension control in the control volume of the given circular knitting machine system.