• International Journal of CAD/CAM
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• v.1 no.1
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• pp.1-9
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• 2002

The STL or Stereolithography format, established by 3D systems, gathers the geometric data of the model in a number of triangular surfaces. It can be in ASCII or binary format, and is a de facto standard in the Rapid Prototyping (RP) world. RP has developed greatly over the last ten years. In particular, improvement in materials has meant greater part accuracy and strength, which in turn has increased the range of functional applications. Future applications of RP will focus on rapid tooling and direct manufacturing. Direct manufacturing in particular may see much benefit from the incorporation of color into models. For color RP, besides designing new hardware to add color into the prototypes, it is necessary to redefine the CAD software for adding and accurately positioning color onto the model. STL cannot effectively store this kind of information. Among the existing data file formats, VRML is an acceptable one that is complimentary to existing RP processes. This paper acts as a review to discuss several methods of using VRML for coloring model data. This paper will also discuss the problems occurred in coloring the layer contours of the RP model.

• Structural Engineering and Mechanics
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• v.90 no.2
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• pp.117-125
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• 2024

This article presents the behaviour and design of cold-formed steel (CFS) web-stiffened lipped channel beams that primarily fail owing to the buckling interaction of distortional and global buckling modes. The incorporation of an intermediate stiffener in the web of the lipped channel improved the buckling performance leads to distortional buckling at intermediate length beams. The prediction of the strength of members that fail in individual buckling modes can be easily determined using the current DSM equations. However, it is difficult to estimate the strength of members undergoing buckling interactions. Special attention is required to predict the strength of the members undergoing strong buckling interactions. In the present study, the geometric dimensions of the web stiffened lipped channel beam sections were chosen such that they have almost equal distortional and global buckling stresses to have strong interactions. A validated numerical model was used to perform a parametric study and obtain design strength data for CFS web-stiffened lipped channel beams. Based on the obtained numerical data, an assessment of the current DSM equations and the equations proposed in the literature (for lipped channel CFS sections) is performed. Suitable modifications were also proposed in this work, which resulted in a higher level of design accuracy to predict the flexural strength of CFS web stiffened lipped channel beams undergoing distortional and global mode interaction. Furthermore, reliability analysis was performed to confirm the reliability of the proposed modification.

• Wind and Structures
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• v.13 no.2
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• pp.191-206
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• 2010

Windborne debris is a major cause of structural damage during severe windstorms and hurricanes owing to its direct impact on building envelopes as well as to the 'chain reaction' failure mechanism it induces by interacting with wind pressure damage. Estimation of debris risk is an important component in evaluating wind damage risk to residential developments. A debris risk model developed by the authors enables one to analytically aggregate damage threats to a building from different types of debris originating from neighboring buildings. This model is extended herein to a general debris risk analysis methodology that is then incorporated into a vulnerability model accounting for the temporal evolution of the interaction between pressure damage and debris damage during storm passage. The current paper (Part I) introduces the debris risk analysis methodology, establishing the mathematical modeling framework. Stochastic models are proposed to estimate the probability distributions of debris trajectory parameters used in the method. It is shown that model statistics can be estimated from available information from wind-tunnel experiments and post-damage surveys. The incorporation of the methodology into vulnerability modeling is described in Part II.

• Transactions of Materials Processing
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• v.9 no.5
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• pp.512-525
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• 2000

Designers are frequently faced with multiple quality issues in injection molded parts. These issues are usually In conflict with each other, and thus tradeoff needs to be made to reach a final compromised solutions. The objective of this study is to develop an automated injection molding design methodology, whereby part defects such as warpage and weld line are optimized. The features of the proposed methodology are as follows: first, Utility Function approach is applied to transform the original multiple objective problem into single objective problem. Second is an implementation of a direct search-based Injection molding optimization procedure with automated consideration of process variation. The Space Reduction Method based on Taguchi's DOE(Design Of Experiment) is used as a general optimization tool in this study. The computational experimental verification of the methodology was partially carried out for a can model of Cavallero Plastics Incorporation, U. S. A. Applied to production, this study will be of immense value to companies in reducing the product development time and enhancing the product quality.

• Computers and Concrete
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• v.12 no.1
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• pp.19-36
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• 2013

In the finite element analysis of reinforced concrete structures, discrete representation of the steel reinforcing bars is considered advantageous over smeared representation because of the more realistic modelling of their bond-slip behaviour. However, there is up to now limited research on how to simulate the dowel action of discrete reinforcing bars, which is an important component of shear transfer in cracked concrete structures. Herein, a numerical model for the dowel action of discrete reinforcing bars is developed. It features derivation of the dowel stiffness based on the beam-on-elastic-foundation theory and direct assemblage of the dowel stiffness matrix into the stiffness matrices of adjoining concrete elements. The dowel action model is incorporated in a nonlinear finite element program based on secant stiffness formulation and application to deep beams tested by others demonstrates that the incorporation of dowel action can improve the accuracy of the finite element analysis.

• Proceedings of the Korean Nuclear Society Conference
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• 1995.05a
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• pp.636-643
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• 1995

The accurate determination of the fuel-cladding gap conductance as functions of rod burnup and power level may be a key to the design and safety analysis of a reactor. The incorporation of a sophisticated gap conductance model into nuclear design code for computing thermal hydraulic feedback effect has not been implemented mainly because of computational inefficiency due to complicated behavior of gap conductance. To avoid the time-consuming iteration scheme, simplification of the gap conductance model is done for the current design model. The simplified model considers only the heat conductance contribution to the gap conductance. The simplification is made possible by direct consideration of the gas conductivity depending on the composition of constituent gases in the gap and the fuel-cladding gap size from computer simulation of representative power histories. The simplified gap conductance model is applied to the various fuel power histories and the predicted gap conductances are found to agree well with the results of the design model.

• Bulletin of the Korean Chemical Society
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• v.33 no.6
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• pp.1983-1988
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• 2012

Stem cell transplantation is emerging as a possible new treatment for liver cirrhosis, and recent animal studies have documented the benefits of stem cell therapy in a hepatic fibrosis model. However, the underlying mechanism of stem cell therapy is still unclear. Among the proposed mechanisms, the cell replacement mechanism is the oldest and most important, in which permanently damaged tissue can be replaced by normal tissue to restore function. In the present study, Cy5.5-labeled superparamagnetic iron oxide (SPIO) was used to label human mesenchymal stem cells. The uptake of fluorescently labeled nanoparticles enabled the detection and monitoring of the transplanted stem cells; therefore, we confirmed the direct incorporation and differentiation of SPIO into the hepatocyte-like transplanted stem cells by detecting human tyrosine aminotransferase (TAT), well-known enzymatic marker for hepatocyte-specific differentiation.

• Bulletin of the Korean Chemical Society
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• v.11 no.5
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• pp.386-390
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• 1990

Yttrium oxysulfide incoporated with europium has been prepared by direct heating the mixture of $Y_2O_3,\;Eu_2O_3,\;NaOH(or\;Na_2CO_3)$, and S. The reaction of the mixture at low temperatures and treatment at higher temperatures are studied. The formation of $Y_2O_2S$ is completed at lower temperature (ca. 500$^{\circ}C$) and incorporation of $Eu^{3+}$ into $Y_2O_2S$ lattice proceeds at higher temperature (above 1000$^{\circ}C$) along with crystal growth. Small amount of the unknown phase considered to be $Y_2O_2S_2$ is formed along with $Y_2O_2S$ in the temperature range from 400$^{\circ}C$ to 460$^{\circ}C$.

• Polymer(Korea)
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• v.36 no.6
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• pp.761-767
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• 2012

The polycarbonate (PC)-based optical diffusers for direct-lit LED backlight unit were prepared by using extrusion compounding followed by compression molding process. The application of inorganic porous silica particles as a diffusing agent in addition to conventional poly(methyl methacrylate) (PMMA) beads was attempted, and the optical, thermal, and mechanical properties of the prepared diffusers were investigated. The morphological observations revealed that the diffusing agents could be uniformly dispersed in the PC matrix without agglomeration by high shear stress generated during extrusion process. The incorporation of the porous silica particles mixed with PMMA beads remarkably enhanced the luminance uniformity with respect to both location and view angle for the diffuser, while minimizing the reduction in the absolute luminance, as compared with the diffuser containing only PMMA beads. In addition, thermal and mechanical properties of the diffusers were shown to be improved upon addition of the porous silica particles.

• Food Engineering Progress
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• v.15 no.1
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• pp.80-84
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• 2011

The effects of incorporating hot water extract of Schisandra chinensis fruit on the physicochemical and sensory properties of Sikhe were investigated. The extract was incorporated at 5 levels (0, 10, 20, 30, 40, and 50%, v/v) by replacing equivalent amount of distilled water. The pH decreased while the soluble solids content increased significantly with the increase in the extract replacement (p<0.05). Redness ($a^*$-value) increased significantly as the extract concentration increased (p<0.05); on the other hand, lightness ($L^*$-value) and yellowness ($b^*$-value) did not show any direct relationships with the extract replacement. Color, sour taste, and sweet taste except for Sikhe flavor were distinctively classified by the sensory analyses (p<0.05). Correlation analysis indicated that level of extract incorporation was well-correlated with all the physicochemical and sensory properties studied except for $L^*$- and $a^*-$ value. Finally, the consumer test based on Friedman-type statistic, suggested that 10% incorporation of the hot water extract of Omija fruit was recommended for making Sikhe.