Shih-Hsuan Chiu

Dynamic flame retardancy of polypropylene filled with ammonium polyphosphate, pentaerythritol and melamine additives

Abstract The dynamic flammability properties of an intumescent fire retardant polypropylene filled with ammonium polyphosphate, pentaerythritol and melamine was discussed in this study. To evaluate the flammability properties of the materials, limit oxygen index, smoke emission, tensile strength, and our exploitation ‘dynamic flammability evaluation system’ tests were assessed in experiments. The results showed that the intumescent fire retardant filled polypropylene has superior flammability properties and keeps its mechanical strength. It also can be seen that CO concentration and smoke emission decrease while burning. It is concluded that this intumescent system additives is an effective flame retardant on improving combustion properties for polypropylene.

The dynamic flammability and toxicity of magnesium hydroxide filled intumescent fire retardant polypropylene

The flammability properties of an intumescent fire retardant polypropylene added with magnesium hydroxide was discussed in this study. To evaluate the flammability of the material, limit oxygen index, smoke emission, tensile strength, and our exploitation dynamic flammability evaluation system, tests were assessed in experiments. The results showed that the intumescent flame retardant ammonium polyphosphate-filled polypropylene has superior flammability properties but higher carbon oxide (CO) concentration and smoke density. By adding some magnesium hydroxide additives in intumescent fire retarded polypropylene, the smoke density and CO concentration decrease; and the compound also has superior fire properties. It is concluded that intumescent system and magnesium hydroxide additives are effective on improving combustion properties for polypropylene.

An effective voting method for circle detection

The drawbacks of the standard Hough transform (SHT) are the large computation and the large storage requirement. Moreover, the voting method of SHT plays an important role to affect the pattern detection accuracy. In this paper, a new voting method is proposed to reduce the computation and the storage requirements of SHT for circle detection. This method improves the efficiency of circle detection by letting each pixel only belong to one candidate of circle parameters. Synthetic images and real images are used to show the capability of the proposed method.

A study of the combustion and fire-retardance behaviour of unsaturated polyester/phenolic resin blends

Abstract The thermal degradation and combustion behaviour of an interpenetrating network (IPN) structure of unsaturated polyester UP resin and a resole type of phenolic resin was studied. Thermal gravimetric analysis (TGA) was used to monitor the degree of thermal decomposition for the UP/phenol IPN structure and the change of the oxygen index (OI) was used to describe the variation of the combustion behaviour. The smoke density was measured via a non-flaming process to detect the amount of smoke generated during the combustion. A homemade cone calorimetric dynamic flammability evaluation system was assembled to analyse the gas evolved and to measure the heat release rate (HRR) during the combustion. Under simulated conditions of a burning field at the temperature of 757°C, the variation of the concentration of carbon monoxide (CO) and the HRR of the UP/phenol IPN structure were studied. The results show that modification of the essentially flammable UP resin by the phenol structure to form an IPN system cannot only remarkably improve the heat resistance but also help to suppress the smoke, toxic gas and heat release during the combustion.

Preparation and Characterization of Bioplastic-Based Green Renewable Composites from Tapioca with Acetyl Tributyl Citrate as a Plasticizer

Granular tapioca was thermally blended with poly(lactic acid) (PLA). All blends were prepared using a plasti-corder and characterized for tensile properties, thermal properties and morphology. Scanning electron micrographs showed that phase separation occurred, leading to poor tensile properties. Therefore, methylenediphenyl diisocyanate (MDI) was used as an interfacial compatibilizer to improve the mechanical properties of PLA/tapioca blends. The addition of MDI could improve the tensile strength of the blend with 60 wt% tapioca, from 19.8 to 42.6 MPa. In addition, because PLA lacked toughness, acetyl tributyl citrate (ATBC) was added as a plasticizer to improve the ductility of PLA. A significant decrease in the melting point and glass-transition temperature was observed on the basis of differential scanning calorimetry, which indicated that the PLA structure was not dense after ATBC was added. As such, the brittleness was improved, and the elongation at break was extended to several hundred percent. Therefore, mixing ATBC with PLA/tapioca/MDI blends did exhibit the effect of plasticization and biodegradation. The results also revealed that excessive plasticizer would cause the migration of ATBC and decrease the tensile properties.

Defect Segmentation of Texture Images with Wavelet Transform and a Co-occurrence Matrix

Defect segmentation of complicated textures is a challenging problem in automatic inspection. In this paper, we use wavelet transform (WT) and a co-occurrence matrix (CM) to extract features of texture images, then use those features to locate defects on textile fabrics. From the experimental results, we obtain a 92% accuracy rate when determining if the inspected image is with or without defects and an 84% accuracy rate when locating the defect position in an image with defects. We also find that the methods performance is invariant under geometric transformation. This method can be extensively applied to automatic surface defect inspection of other materials such as wood and metal.

In-line viscosity control in an extrusion process with a fuzzy gain scheduled PID controller

In the extrusion process, rapidly tracking the set point of quality factor and eliminating its variation to reduce the off-specification product is important. In this study, the fuzzy gain-scheduled proportional-integral-derivative (PID) controller is used to control the melt viscosity during extrusion processing. A second-order model related to the viscosity and the extruder screw speed is developed empirically to approximate the extrusion system. It is concluded that, in comparison to the well-known Zeigler-Nichols PID tuning control scheme, the performances of the proposed control strategy is preferable both in simulation and implementation.

Textural Defect Segmentation Using a Fourier-Domain Maximum Likelihood Estimation Method

When automatically inspecting textured surface defects, the most important step is to segment the defects from the background. For complicated textures, however, defect segmentation is still a challenging problem. In this paper, we use a Fourier-domain maximum likelihood estimator (FDMLE) based on the fractional Brownian motion (FBM) model to inspect surface defects of textile fabrics. From the experiments, we obtain good results for defect segmentation, and find the methods performance is invariant under geometric transformation.

In-line viscosity fuzzy control

A fuzzy control strategy on viscosity of a polymeric melt during the extruding processes is proposed to ensure producing the quality-consistent end products. Because the viscosity model in the control system varies with respect to different conditions of the system command (e.g., screw speed), we focus on using a fuzzy controller accomplished with a fuzzy modeling technique to solve the model-variant viscosity control system. Also, system stability analysis is presented. According to the simulation and the implementation results, better performances and a suitable using method are concluded.

A FAST RANDOMIZED HOUGH TRANSFORM FOR CIRCLE/CIRCULAR ARC RECOGNITION

The main drawbacks of the Hough transform (HT) are the heavy requirement of computation and storage. To improve the drawbacks of the HT, the randomized Hough transform (RHT) was proposed. But the RHT is not suitable for detecting the pattern with the complex image because the probability is too low. In this paper, we propose a fast randomized Hough transform for circle/circular arc detection. We pick one point at random to be the seed point. Then, we propose a checking rule to confirm if the seed point is on the true circle. Compared with the previous techniques, the proposed method requires less computational time and is more suitable for complex images. In the experiments, synthetic and real images are used to show the effect of the proposed method.