Abstract: Recently, glass fiber reinforced polymer plastic (GFRP) pipes are widely used in the water-supply system because of their advantages such as light-weight, corrosion resistance, etc. In previous study, we present the equation to predict stiffness factor (EI) of GFRP pipe with two tape-winding FRP layers and polymer mortar layer in between two FRP layers. As a result, it was able to predict in the range of -3% to +7%. In addition to previous study, we attempted to predict stiffness factor (EI) of GFRP pipe by the finite element method (MIDAS Civil 2016). From the study it was found that the finite element method can be used to predict the pipe stiffness of GFRP pipe.
Abstract: The cooling water intake pipeline constructed in the nuclear power plant is mostly made of steel or concrete. However, they have some disadvantages such as reduced durability due to wear and corrosion caused by sea water, defects in connections, breakage of pipelines, and difficulties in continuous maintenance. To mitigate the presented problems, recently, the research on durable and outstanding corrosion resistant glass fiber reinforced polymer plastic (GFRP) pipe has been actively conducted. In this experimental study, 2400 mm (94.49 in) diameter of GFRP pipe specimen is investigated. The field test was planned to measure ring deflection of buried GFRP pipe. In addition, the design method proposed by American Water Works Association (AWWA) M 45 was applied to compute the ring deflection of pipe and then compared the predicted results with the experimental results.
Abstract: Cellulose nanofibers (CNFs) were used as biobased fillers to prepare poly(lactic acid) (PLA)-based biocomposites. Cellulose nanofibers were extracted from cassava pulp (CP) by acid hydrolysis method. Before submitted to acid treatment, CP was pre-treated by alkali and bleaching treatments. The biocomposites were prepared by melt mixing, followed by hot melt pressing. In order to improve the compatibility of CNFs with PLA matrix, glycidyl methacrylate (GMA) grafted poly (lactic acid) (PLA-g-GMA) was used as a compatibilizer. PLA-g-GMA was prepared by grafting of GMA onto PLA chain via melt mixing using an internal mixer. Transmission electron microscopy (TEM) micrograph shows that most nanofibers with the diameter in the range of 10-30 nm and immeasurable length were obtained. The appearance of two new peaks at 49.07 and 44.71 ppm in the carbon-13 nuclear magnetic resonance (13C-NMR) spectrum of PLA-g-GMA, which represent the carbons of the epoxy group of GMA, confirms that GMA was successfully grafted onto PLA chain. The morphology of biocomposites, characterized by scanning electron microscopy (SEM), reveals that without using PLA-g-GMA, the poor dispersion of CNFs in PLA matrix was observed. In contrast to that, with using PLA-g-GMA, the dispersion of CNFs in PLA matrix was improved. Moreover, the impact strength results show that by incorporating 1.0 wt% CNFs into PLA matrix and using PLA-g-GMA as a compatibilizer, the impact strength of biocomposites was slightly enhanced compared to that of pure PLA.
Abstract: This paper describes the characterization of conductive PDMS (CPDMS) composites. Composite have been achieved by filling the PDMS with CarbonBlack (CB). Two different methods were used to prepare the CPDMS composites: (A) direct mixing of CB with PDMS (CB-PDMS); (B) dissolving of CB in methanol before mixing with PDMS (CB-Methanol-PDMS). At a certain critical CB concentration, called percolation threshold, the membranes get conductive. Membranes of CPDMS (thickness ≈ 100µm) have been fabricated. CPDMS membranes of method (B) show a smoother surface profile as membranes of method (A). By means of a two–point resistivity measurement, the electrical resistance of CPDMS membranes was measured. With an increase of the CB concentration, the resistance decreases. Membranes of method (B) show a low percolation threshold and a low surface resistivity. Effects of pressure and temperature on the membrane resistance were investigated, too. Around the percolation threshold, the resistance shows the highest sensitivity on pressure and temperature variations. The Young’s modulus of CPDMS membranes exponentially increase with an increase of the CB concentration.
Abstract: In the analysis of life cycle cost (LCC) according to the usage of all-composite structure, this study verified that economic operating cost impact occurring during operation is more important component than simple purchase cost in the review based on various economic components. Namely, all-composite structure requires the highest production costs based on LCC analysis, but entire LCC and ecological impact in the socio-economic aspect are important variables and all-composite structure is clearly the optimum alternative.
Abstract: A356/Al2O3 composites with Sr modifier were produced by stir casting process. The composites were further heat treated to obtain light material with superior characteristics through precipitation hardening of Mg2Si precipitate. The A356 alloy is reinforced with 10 %Vf Al2O3 micro particles. Small amount of Sr is added to modify eutectic silicon morphology from plate-like into fibrous. The composites were prepared by stir casting method in order to obtain dispersed reinforcement particulates within the matrix. T6 heat treatment is employed to the fabricated composites for 2, 4, 6, 8, and 10 hours of aging time to improve the properties. The result reveals that an optimum values of tensile strength, impact strength, hardness and wear rate are achieved by conducting 6 hours of aging. Longer than that, the properties will decline as a result of incoherent phase domination. Small amount of Sr is shown to be able to change the morphology of eutectic silicon from plate-like into fibrous. However, Fe-intermetallics formation, porosity, and negative effect from solution treatment due to improper technical condition during heat treatment are found to contribute on deterioration of mechanical properties of the material.
Abstract: Titanate Ribbon (Na2Ti3O7) used in ABS plastic was synthesized to study the mechanical properties and to conduct test on the E-coli bacteria inhibition performance. The polymer blends of ABS/Na2Ti3O7 by Na2Ti3O7, was synthesized through alkaline hydrothermal reaction with 0.5 grams of titanium dioxide as a precursor with 20 ml. of sodium hydroxide (NaOH) at the concentration of 10 molar under the alkalinity at 200 ° c for 24 hours. The study on the microstructure by scanning electron microscope revealed that the Layered structure was shaped as a complete ribbon. The mechanical testing activities on the E-coli bacteria inhibition polymer mixed ABS/Na2Ti3O7; it was found that the mechanical properties for ABS/Na2Ti3O7, The results showed that tensile modulus and tensile strength of blending Na2Ti3O7 at 0.5 %wt was the highest. The result showed that E.coli could reduce up to 66.01%.
Abstract: Solid-liquid phase change material (PCM) is of high phase change heat and application potentials of thermal energy storage. In this paper, the thermal performance of PCM composites of sodium acetate and urea are investigated through experiment. Moreover, the main thermal-physical properties of such PCM composites with different mixing mass ratios are obtained through T-history method. The results show that with the rising urea mass fraction, both the phase change temperature and latent heat of fusion (enthalpy) decline. It also indicates that strontium sulfate is an effective nucleating additive to decrease super-cooling degree during solidification process for such composite PCM. This work is of high significant in improving the thermal performance of PCM composite and extending its applications.
Abstract: Octavinyl polyhedral oligomeric silsesquioxane (POSS) were used to hybrid with polysiloxane matrix by two methods, physical blending (PB) and chemical modification (CM). Mechanical, thermal and morphological properties of composites were studied by changing the percentage of POSS and investigated by thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and wide angle X-ray diffraction (XRD) measurements. The results show that the hybrid composites have better mechanical and thermal property than the parent polymer matrix, and CM-prepared composites show better reinforcing role compared with PB-prepared samples. The CM method was hydrosilylation reaction of octavinyl-POSS with hydrogen terminated poly(methylphenylsiloxane) (HPMPS) and the FTIR and NMR results of modified POSS revealed that hydrosilylation reaction took place successfully but was not complete. The modified POSS consisting partial segments of HPMPS attached to the central POSS core showed better distribution in matrix than PB-prepared POSS hybrid composites.