• KIPS Transactions on Computer and Communication Systems
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• v.13 no.1
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• pp.1-9
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• 2024

In the development and mass production of polymers, there are many uncontrollable variables. Even small changes in chemical composition, structure, and processing conditions can lead to large variations in properties. Therefore, Traditional linear modeling techniques that assume a general environment often produce significant errors when applied to field data. In this study, we propose a new modeling method (GPR-SEM) that combines Structural Equation Modeling (SEM) and Gaussian Process Regression (GPR) to study the Friction-Coefficient and Flexural-Strength properties of Polyacetal resin, an engineering plastic, in order to meet the recent trend of using plastics in industrial drive components. And we also consider the possibility of using it for materials modeling with nonlinearity.

• Transactions of Materials Processing
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• v.17 no.7
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• pp.496-500
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• 2008

Plastics is commonly used in consumer electronics because of it is high strength per unit mass and good productivity. But plastic parts are usually distorted after injection molding due to the residual stress after filling, packing, cooling process, and etc. And plastic material is to be deteriorated according to various temperature conditions and operating time, which can be characterized by stress relaxation and creep. The viscoelastic behavior of plastic materials in time domain can be expressed by the Prony series of the commercial code, ABAQUS. In the paper, the process to predict the post deformation under cyclic thermal loadings was suggested. The process was applied to the real panel, and the deformation predicted by the analysis was compared with that of real test, which showed the possibility of applying the suggested process to predict the post deformation of plastic product under thermal loadings.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.1
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• pp.108-112
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• 2006

A Study of birefringence in an aspheric lens of injection molding became more important to improve its optical properties. In the present study, the experimental study was carried out to investigate the relationship between birefringence and injection molded conditions. The processing factors are conditions include packing pressure, packing time, injection speed, melt temperature of optical resin and wall temperature. Birefringence was observed figures by using a polarizer in light. This experiments were carried out using the simulation software and injection molding machine.

• 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.

• Fibers and Polymers
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• v.2 no.1
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• pp.163-172
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• 2001

To determine three-dimensional fiber orientation states in injection-molded short fiber composites a CLSM (Confocal Laser Scanning Microscope) is used. Since the CLSM optically sections the composites, more than two cross-sections either on or below the surface of the composite can be obtained. Three dimensional fiber orientation states can be determined with geometric parameters of fibers on two parallel cross-sections. For experiment, carbon fiber reinforced polystyrene is examined by the CLSM. Geometric parameters of fibers are measured by image analysis. In order to compactly describe fiber orientation states, orientation tensors are used. Orientation tensors are determined at different positions of the prepared specimen. Three dimensional orientation states are obtained without the difficulty in determining the out-of-plane angles by utilizing images on two parallel planes acquired by the CLSM. Orientation states are different at different positions and show the shell-core structure along the thickness of the specimen.

• International Journal of Ocean System Engineering
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• v.1 no.4
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• pp.180-184
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• 2011

Nanocomposites based on cellulose nanofibers have been studied for a considerable time since its first introduction, however real applications seem to have hardly developed to these days. The high-strength of cellulose nanofibers suggests the potential to reinforce plastics to produce composites for semi-structural or even structural applications. This paper discusses some of the attempts to produce such high-strength nanocomposites and the main challenges that have to be overcome to bring them into commercial products.

• Journal of Mechanical Science and Technology
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• v.14 no.5
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• pp.477-482
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• 2000

This study discusses a non-contact optical technique (electronic speckle pattern interferometry) that is well suited for thermal deformation measurement without any surface preparation and compensating process. Fiber reinforced plastics ($[0]_{16},\;[0/90]_{8S}$) were analyzed by ESPI to determine their thermal expansion coefficients. The thermal expansion coefficient of the transverse direction of a uniaxial composite is evaluated as $48.78{\times}10^{-6}(1/^{\circ}C)$. Also, the thermal expansion coefficient of the cross-ply laminate $[0/90]_{8S}$ is numerically estimated as $3.23{\times}10^{-6}(1/^{\circ}C)$ that is compared with that measured by ESPI.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10b
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• pp.197-198
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• 2003

Poly(butylene terephthalate)(P5T) has long history as an engineering thermoplastic. PBT was first introduced commercially to the market place as an injection molding resin about 1969 by Celanese Plastics in the U.S.A. It is still widely used as a molding resin. Processing or forming methods for solid-phase deformation, such as stretching, hydrostatic extrusion. roller stretching, rolling, and so on can improve the mechanical properties effectively. (omitted)

• Macromolecular Research
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• v.8 no.6
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• pp.261-267
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• 2000

It is well known that poly(cyclohexylene dimethylene terephthalate) (PCT) is used as the engineering plastics with high melting temperature and fast crystallization rate compared with poly(butylene terephthalate)(PBT). However, poor thermal stability of PCT has limited its practical application due to the drastic decrease of molecular weight during the processing temperature. In order to improve the thermal stability of PCT homopolymer, the copolymer of PCT and PBT was synthesized and the thermal properties of the copolymer have been studied. P(CT/BT) copolymer was obtained by condensation polymerization of DMT, CHDM, and 1,4-butanediol. The chemical structure and composition of the copolymer was investigated by FTIR and NMR analysis. The thermal behavior of copolymer was studied using DSC and it was found that the crystallization-melting behavior of the copolymer was observed for the whole composition range. TGA analysis exhibited that P(CT/BT) copolymer is more stable at the initial stage of thermal decomposition compared with PCT and PBT homopolymers.

• Preventive Nutrition and Food Science
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• v.4 no.2
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• pp.152-158
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• 1999

Polystyrene is frequently used for food packaging because of its eaxy processing rigidity , and low cost. Styrene, which is present in detectable amouts in the polymer, is usually considered to be the substance responsible for the possible tainting of a polystyrene-packed food by migration. The contamination of foods and beverages by trace amounts of materials which have migrated from plastics use din packaging is a concern both on the grounds of adversely affecting product quality and of food safety. These lead to increasing attention to the potentional hazards of a large variety of plastic materials and foods. In this paper we reviewed the history of Styrene and various analytical methods of sample preparation and detection to assess the extent to which styrene is present in food-grade polystrene materials and to what extent it leaked into foods and food stimulants.