• Advances in concrete construction
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• v.10 no.2
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• pp.171-183
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• 2020

The main objective of this study is the assessment of the ability of limestone mortars to resist to different chemical attacks. The ability of polypropylene (PP) fibres waste used as reinforcement of these concrete materials to enhance their durability is also studied. Crushed sand 0/2 mm which is a fine limestone residue obtained by the crushing of natural rocks in aggregates industry is used for the fabrication of the mortar. The fibres used, which are obtained from the waste of domestic plastic sweeps' fabrication, have a length of 20 mm and a diameter ranging between 0.38 and 0.51 mm. Two weight fibres contents are used, 0.5 and 1%. The durability tests carried out in this investigation included the water absorption by capillarity, the mass variation, the flexural and the compressive strengths of the mortar specimens immersed for 366 days in 5% sodium chloride, 5% magnesium sulphate and 5% sulphuric acid solutions. A mineralogical analysis by X-ray diffraction (XRD) and a visual inspection are used for a better examination of the quality of tested mortars and for better interpretation of their behaviour in different solutions. The results indicate that the reinforcement of limestone mortar by PP fibres waste is an excellent solution to improve its chemical resistance and durability. Moreover, the presence of PP fibres waste does not affect significantly the water absorption by capillarity of mortar nether its mass variation, when exposed to chloride and sulphate solutions. While in sulphuric acid, the mass loss is higher with the presence of PP fibres waste, especially after an exposure of 180 days. The results reveal that these fibres have a considerable effect of the flexural and the compressive behaviour of mortar especially in acid solution, where a reduction of strength loss is observed. The mineralogical analysis confirms the good behaviour of mortar immersed in sulphate and chloride solutions; and shows that more gypsum is formed in mortar exposed to acid environment causing its rapid degradation. The visual observation reveals that only samples exposed to acid attack during 366 days have showed a surface damage extending over a depth of approximately 300 ㎛.

• Advances in materials Research
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• v.3 no.3
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• pp.175-183
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• 2014

Natural rubber bound phenolic antioxidant, 2,6-di-tert-butyl-4-vinylphenol (2,6-DBVP), was prepared from natural rubber and 2,6-DBVP in both solution and melt state. The 2,6-DBVP had been synthesized from 3,5-di-tert-butyl-4-hydroxybenzaldehyde and methyltriphenylphosphonium iodide ($MePPh_3I$) by Wittig reaction ($0^{\circ}C$ for 2 hrs, $N_2$ atmosphere). The conditions for preparation of natural rubber bound 2,6-DBVP (NR-DBVP) were optimized for both solution state (1 phr BPO and 8 phr 2,6-DBVP at $70^{\circ}C$ for 2 hrs) and for melt state (1 phr BPO and 8 phr 2,6-DBVP at $70^{\circ}C$ for 10 mins, with rotor speed of 60 rpm). A thermoplastic vulcanizate was obtained using a compatibilizer, polypropylene modified with phenolic resin (PhHRJ-PP), in a closed mixer ($180^{\circ}C$ for 3 mins, rotor speed 60 rpm). The antioxidant properties of vulcanized NR-DBVP, using phenolic as the vulcanization system, were similar to NR with the conventional antioxidant BHT. In addition, the antioxidant, water leaching property of the thermoplastic vulcanizate of NR-DBVP/PP were good in comparison to a NR blend with BHT; the morphologies of these thermoplastic vulcanizates were similar.

• Textile Coloration and Finishing
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• v.34 no.1
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• pp.20-26
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• 2022

Centrifugal spinning is an emerging technique for fabricating micro-to-nano-fibers in recent years. To obtain fibers with the desired size and morphology, it is necessary to configure and optimize the parameters used in centrifugal spinning. In this study, it was controlled by changing the solution's concentration (7.5, 10, and 12.5 wt.%) and disk's rotational velocity (6,000, 8,000, and 10,000 rpm) to prepare centrifugal spun nano-filter. The morphological property, air permeability, and dust collection efficiency of the PVA/PP bi-layer nanoweb prepared by centrifugal spun PVA on the PP micron nonwoven substrate are studied using a field emission scanning electron microscope, an air permeability tester, and a filter tester equipment, and the analysis results indicate that it is suitable as a nano-filter when the concentration of PVA solution is 10 wt.% and the rotational velocity of the disk is 8,000 rpm. The resultant reduced diameter and uniform fibers also proved that an excellent dust collection efficiency filter could be made.

• Applied Chemistry for Engineering
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• v.7 no.5
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• pp.938-945
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• 1996

The present studies are to describe the grafting reaction of styrene in various solvents to polypropylene fabric by the simultaneous method using Co-60. The influence of various factors such as absorbed dose, dose rate, type of solvent, acid and multifunctional monomer were evaluated. At constant absorbed dose, the grafting yield was found to be higher at low dose rate. The initial rate of grafting was found to be proportional to a 0.56 power of dose rate. The inclusion of mineral acid in the grafting solution led to an increase in radiation grafting yield at almost all monomer concentration examined. Multifunctional monomer was also effective to increase grafting yield. The addition of both acid and multifunctional monomer was found to accelerate the grafting yield much more than the separate addition of two additives.

• Korean journal of applied entomology
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• v.41 no.2
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• pp.99-105
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• 2002

A gregarious pupal endoparasitoid Tetrastichsus sp. (Hymenoptera: Eulophidae) was reared in vitro from oviposition to adult emergence on an artificial host. The host pupal case was made using 0.02 mm-thick polypropylene film, and was filled with a diet consisting of powders of Antheraea pernyi pupa, chicken yolk, infant formula, royal jelly, and Neisenheimer's salt solution. Female parasitoids reared in the artificial host produced smaller sized progeny than those reared in in vivo, but the adults reproduced fertile offsprings. Furthermore in vitro second-generation (G$_2$) females showed more improved biological characteristics, compared with their parents. The fecundity (mean no. adult progeny), oviposition period (days), and longevity (days) of G$_2$ female were evaluated as 45.7, 7.8, and 13.8, respectively Female biased sex ratio was obtained with 76.9% female progeny. The results demonstrated that Tetrastichus sp. is a promising parasitoid for in vitro mass production.

• Applied Chemistry for Engineering
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• v.29 no.2
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• pp.168-175
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• 2018

In order to investigate the effect of the chemical treatment of bamboo fiber on physical properties of polypropylene (PP)/bamboo fiber (BF) composites, silane coupling agents such as ${\gamma}$-aminopropyltriethoxysilane (APS), ${\gamma}$-glycidoxypropyl-trimethoxysilane (GPS) and ${\gamma}$-mercaptopropyltrimethoxysilane (MRPS) were applied to BF and alkaline treated BF. Morphological properties of the chemically treated BF were confirmed by optical microscope and SEM measurements, and chemical structure changes were confirmed by FT-IR and EDS. TGA results showed that the thermal stability of silane treated BF increased. Based on the analysis of a universal testing machine and an Izod impact test, the flexural and impact properties of PP/silane treated BF composites showed higher values than those of PP/BF composites. The enhancement of interfacial adhesion properties of the PP/BF composite was checked from SEM images of the fracture of specimens after the tensile test.

• Polymer(Korea)
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• v.26 no.1
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• pp.121-127
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• 2002

We investigated uranium adsorption and adsorption process characteristics in brine water, changing column bed height packed with amidoximated polypropylene-g- acrylonitrile (AOPP-g-AN) fibrous ion-exchanger. Swelling ratios of AOPP-g-AN in fibrous ion-exchanger were 8.54g/g $H_2O_2$ and 8.87 g/g for $H_2O_2$ solvent respectively. Ion exchange capacity increased with degree of graft and showed the maximum, 3.99 meq/g at 100% degree of graft. In batch process, uranium adsorption had reached an initial equilibrium in 10 min with the adsorption rate of 9.5 mg/min. Finial adsorption capacity was 3.95 meq/g, and pH effect could not be observed. In continuous process, adsorption capacity depended on various packing ratios and showed the maximum, 3.92 meq/g at L/D=1. In L/D<2, breakthrough curve was shown two step by channeling flow and ununiform adsorption. Breakthrough time and adsorption capacity were 26 min and 3.63 meq/g, respectively, in brine water adsorption. When compared with actual brine water and model solution, there was no significant difference of adsorption characteristics.

• Membrane Journal
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• v.8 no.4
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• pp.228-234
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• 1998

Among various water contaminents, organic compounds like phenol are difficult to be removed or destroyed by conventional methods under the unusual discharge conditions. The separation of phenol from aqueous solution has been carried out by several methods recently: absorption by an activated carbon, solvent extraction and liquid membrane technology. The liquid membrane based on water-oil emulsification has been tested as an alternative technology of the conventional technology. In this work, tri-n-butyl phosphate(TBP) and liquid polymers were examined as a liquid membrane in the supported liquid membrane(SLM). The feed concentration of phenol was varied and various types of liquid membranes were used to examine their effects on separation of phenol. It was found that TBP, polypropylene glycol 4000(PPG 4000) and polybutytene glycol 500(PBG 500) were proper carriers because mass transfer rates through them were much higher than or similar to that through methyl isobutyl ketone(MIBK) which was used as a conventional solvent in a solvent extraction process.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.9
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• pp.1274-1280
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• 2012

Defatted grape seed meal protein (DGP) was extracted, and DGP films containing various plasticizers were prepared. To improve the mechanical properties of DGP film, nanoclay or gelatin was incorporated in the film-forming solution to manufacture DGP composite films. Among the plasticizers of fructose (FRU), sucrose (SUC), and polypropylene glycol (PPG), DGP film containing a SUC : PPG ratio of 2.5:0.5 exhibited the best film-forming ability. Addition of Cloisite $Na^+$ improved the mechanical properties of DGP film. Tensile strength (TS) and elongation at break (E) of the film containing 5% Cloisite $Na^+$ were 1.45 MPa and 71.97%, respectively. Regarding the DGP/gelatin composite films, TS and water vapor permeability (WVP) increased with increasing gelatin amount, whereas E decreased. In particular, the DGP/gelatin (2:2) composite film exhibited 20.95 MPa TS and 12.25% E. These results suggest that the DGP film prepared from defatted grape seed meal can be used as a food packaging material.

• Advances in aircraft and spacecraft science
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• v.3 no.1
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• pp.61-75
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• 2016

Climate changes brought on by human interventions have proved to be more devastating than predicted during the recent decades. Recognition of seriousness of the situation has led regulatory organisations to impose strict targets on allowable carbon dioxide emissions from automotive vehicles. As a possible solution, it has been proposed that Fibre Metal Laminate (FML) system is used to reduce the weight of future vehicles. To facilitate this investigation, FML based on steel and self-reinforced polypropylene was stamp formed into dome shapes under different blank holder forces (BHFs) at room temperature and its forming behaviour analysed. An open-die configuration was used in a hydraulic press so that a 3D photogrammetric measurement system (ARAMIS) could capture real-time surface strains. This paper presents findings on strain evolutions at different points along and at $45^{\circ}$ to fibre directions of circular FML blank, through various stages of forming. It was found initiation and rate of deformation varied with distance from the pole, that the mode of deformations range from biaxial stretching at the pole to drawing towards flange region, at decreasing magnitudes away from the pole in general. More uniform strain distribution was observed for the FML compared to that of plain steel and the most significant effects of BHF were its influence on forming depth and level of strain reached before failure.