• Journal of Microbiology and Biotechnology
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• 제29권2호
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• pp.200-208
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• 2019

Probiotics show low cell viability after oral administration because they have difficulty surviving in the stomach due to low pH and enzymes. For the oral delivery of probiotics, developing a formula that protects the probiotic bacteria from gastric acidity while providing living cells is mandatory. In this study, we developed tablets using a new pH-sensitive phthalyl inulin (PI) to protect probiotics from gastric conditions and investigated the effects of different compression forces on cell survival. We made three different tablets under different compression forces and measured survivability, disintegration time, and kinetics in simulated gastric-intestinal fluid. During tableting, there were no significant differences in probiotic viability among the different compression forces although disintegration time was affected by the compression force. A higher compression force resulted in higher viability in simulated gastric fluid. The swelling degree of the PI tablets in simulated intestinal fluid was higher than that of the tablets in simulated gastric fluid due to the pH sensitivity of the PI. The probiotic viability formulated in the tablets was also higher in acidic gastric conditions than that for probiotics in solution. Rapid release of the probiotics from the tablet occurred in the simulated intestinal fluid due to the pH sensitivity. After 6 months of refrigeration, the viability of the PI probiotics was kept. Overall, this is the first study to show the pH-sensitive properties of PI and one that may be useful for oral delivery of the probiotics.

• 천문학회보
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• 제35권2호
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• pp.46.2-46.2
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• 2010

A magnetosonic wave is a longitudinal wave propagating perpendicularly to the magnetic fields and involves compression and rarefaction of the plasma. Lee and Kim (2000) investigated the theoretical solution for the evolution of nonlinear magnetosonic waves in the homogeneous space which adopt the approach of simple waves. We confirm the solution using a one-dimensional MHD code with Total Variation Diminishing (TVD) scheme. Then we apply the solution for the solar wind profiles. We examined the properties of nonlinear waves for the various initial perturbations at near the Lagrangian (L1) point. Also we describe waves steepening process while the shock is being formed by assuming different timescales for a driving source.

• Structural Engineering and Mechanics
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• 제2권4호
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• pp.359-367
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• 1994

The stability behaviour of symmetrically laminated rectangular composite plates with loaded ends clamped and unloaded edges simply-supported, and subjected to uniform in-plane compression is investigated. A numerical and experimental investigation is presented in this contribution. The stacking sequence of the laminated glass/epoxy composite plates is symmetric about the middle surface and consists of 8-ply [0, 90, +45, -45]s lamination. Numerical predictions were obtained through the use of the finite element method. The above plates were modelled with 8-noded isoparametric layered shell elements. The effect of the input parameters such as the degree and forms of prescribed initial imperfection and the incremental step size required for incremental loading, on the convergence of the solution is thoroughly examined. Experimental results are presented for 10 test panels. All test panels were made from glass/epoxy unidirectional prepregs and have aspect ratio of 5.088. The laminate thicknesses were found to vary from 1.054 mm to 1.066 mm. Comparison of experimental data with predicted results show good correlation and give confidence in the finite element model.

• 한국인터넷방송통신학회논문지
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• 제9권1호
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• pp.53-59
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• 2009

다시점 비디오는 데이터 양이 매우 많아서 이를 효과적으로 저장하고 전송하기 위해서는 새로운 압축 부호화의 기술 개발이 필수적이다. 계층적 깊이 영상은 다시점 비디오를 효과적으로 부호화할 수 있는 방법으로 여러 시점의 컬러와 깊이 영상을 합성하여 하나의 데이터 구조로 만든 것이다. 본 논문에서는 실제 거리비교, 오버랩 문제해결, 보간법을 이용한 효율적인 계층적 깊이 영상 표현을 통해서 다시점 영상에 대한 압축 효율을 향상시키는 방법을 제안 하였다. 실험 결과를 통해서 압축 성능 향상을 얻을 수 있었다.

• 한국의류학회지
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• 제33권8호
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• pp.1273-1279
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• 2009

This study examined the difference in the mechanical properties of cotton fabrics treated with nano silver. Nano silver powder, UV-absorber, and DMDHEU are applied to cotton fabrics. The reagents added in a finishing solution were Triton X-100 and $MgCl_2$ $6H_2O$. The mechanical properties of the fabrics were measured by KES-FB system. From these, the primary hand values were evaluated by the conversion equation (KN-202-DS). The results of this study are summarized as follows. The fabric tensile properties and bending properties are increased by the application of nano silver, DMDHEU, and UV-absorber mixed. The values of tensile properties in the warp direction were significantly lower than those in the weft direction. However, the values of bending properties in the warp direction were higher than those in the weft direction. The differences in the values of compression parameters by nano silver coating were unnoticeable. However, the compression energy and resilience of compression in each fabric was increased by DMDHEU treatment. The SMD values of cotton fabrics are decreased by nano silver, DMDHEU, and UV-absorber mixed treatment.

• Computers and Concrete
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• 제9권5호
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• pp.327-340
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• 2012

The search for a design that meets both performance and safety, with minimal cost and lesser environmental impact was always the goal of structural engineers. In general, the design of conventional reinforced concrete structures is an iterative process based on rules of thumb established from the personal experience and intuition of the designer. However, such procedure makes the design process exhaustive and only occasionally leads to the best solution. In such context, this work presents the development and implementation of a mathematical formulation for obtaining optimal sections of reinforced concrete columns subjected to uniaxial flexural compression, based on the verification of strength proposed by the Brazilian standard NBR 6118 (ABNT 2007). To minimize the cost of the reinforced concrete columns, the Simulated Annealing optimization method was used, in which the amount and diameters of the reinforcement bars and the dimensions of the columns cross sections were considered as discrete variables. The results obtained were compared to those obtained from the conventional design procedure and other optimization methods, in an attempt to verify the influence of resistance class, variations in the magnitudes of bending moment and axial force, and material costs on the optimal design of reinforced concrete columns subjected to uniaxial flexural compression.

• Structural Engineering and Mechanics
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• 제72권5호
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• pp.569-583
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• 2019

Tubular steel sections are widespread all over the world because of their strength and aesthetic appearance. Tubular steel members may exhibit local buckling such as elephant foot or overall buckling under extreme compression load. Recently, external bonding of fiber reinforced polymers (FRP) sheets for strengthening these members has been explored through experimental research. This paper presents three-dimensional nonlinear finite element analysis (FEA) to investigate the structural behavior of strengthening tubular steel members with FRP against local and overall buckling phenomena. Out-of-roundness and out-of-straightness imperfections were introduced to the numerical models to simulate the elephant foot and overall buckling, respectively. The nonlinear analysis preferences such as the integration scheme of the shell elements, the algorithm for solution of nonlinear equations, the loading procedure, the bisection limits for the load increments, and the convergence criteria were set, appropriately enough, to successfully track the sophisticated buckling deformations. The agreement between the results of both the presented FEA and the experimental research was evident. The FEA results demonstrated the power of the presented rigorous FEA in monitoring the plastic strain distribution and the buckling phenomena (initiation and propagation). Consequently, the buckling process was interpreted for each mode (elephant foot and overall) into three sequential stages. Furthermore, the influence of FRP layers on the nonlinear analysis preferences and the results was presented.

• 소성∙가공
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• 제19권7호
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• pp.411-415
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• 2010

A sandwich panel which is comprised of truss cores faced with solid face sheets is lightweight and multi-functional. So it is widely used to not only structural material but also heat transfer media in transportation field such as airplane, train and vessel. There are various core topologies such as pyramidal and tetrahedral truss, square honeycombs and kagome truss. The study focused on analytical approach to optimize compression and shear quality of the unit cell of PCM with pyramidal configuration. With various unit cell models which have the same core weight per unit area but different truss member angle, analytical solution for effective stress ($\bar{\sigma},\bar{\tau}$), peak stress ($\bar{\sigma}_{peak},\bar{\tau}_{peak}$) by yielding and buckling, relative density ($\bar{\rho}_c$) and effective stiffness ($\bar{E},\bar{G}$) have been computed and compared each other. With this approach, the most optimal core configuration was predicted. The result has become the efficient guidelines for the design of PCM core structure.

• 소성∙가공
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• 제16권3호
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• pp.187-192
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• 2007

The finite volume method for forging simulation is examined to reveal its possibility as well as its problem in this paper. For this study, the finite volume method based MSC/SuperForge and the finite element method based AFDEX are employed. The simulated results of the homogeneous compression obtained by the two softwares are compared to indicate the problems of the finite volume method while several application examples are given to show the possibility of the finite volume method fur simulation of complex hot forging processes. It is shown that the finite volume method can not predict the exact solution of the homogeneous compression especially in terms of forming load and deformed shape but that it is helpful to simulate very complex forging processes which can hardly be simulated by the conventional finite element method.

• 디지털산업정보학회논문지
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• 제7권2호
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• pp.91-100
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• 2011

Free viewpoint TV can provide multi-angle view point images for viewer needs. In the real world, But all angle view point images can not be captured by camera. Only a few any angle view point images are captured by each camera. Group of the captured images is called multi-view image. Therefore free viewpoint TV wants to production of virtual sub angle view point images form captured any angle view point images. Interpolation methods are known of this problem general solution. To product interpolated view point image of correct angle need to depth image of multi-view image. Unfortunately, multi-view video including depth image is necessary to develop a new compression encoding technique for storage and transmission because of a huge amount of data. Layered depth image is an efficient representation method of multi-view video data. This method makes a data structure that is synthesis of multi-view color and depth image. This paper proposed enhanced compression method using layered depth image representation and H.264/AVC video coding technology. In experimental results, confirmed high compression performance and good quality reconstructed image.