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BÁrÁny Tamás - One of the best experts on this subject based on the ideXlab platform.
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Fröccsöntött amorf poli-alfa-olefin mátrixú önerősített kompozit fejlesztése
Erdélyi Magyar Műszaki Tudományos Társaság (EMT) - Gépészeti Szakosztálya, 2020Co-Authors: Varga, László József, BÁrÁny TamásAbstract:The goal of this study is to produce injection molded all-polypropylene composites at a low injection temperature. As a matrix, we used an amorphous poly-alpha-olefin-based melt-adhesive, as its melting temperature is significantly lower than the melting temperature of the polypropylene homopolymer reinforcement. The composites were produced by injection molding of an impregnated pre-product, and by overmolding of the reinforcing fabric. The composites made of the impregnated pre-product showed unsatisfactory mechanical properties, so the latter method seems to be more promising. Kivonat A kutatás célja alacsony hőmérsékleten fröccsönthető önerősített kompozitok kifejlesztése. Mátrixként amorf poli-alfa-olefin tartalmú ömledékragasztót használtunk, amelynek az olvadási hőmérséklete a polipropilén homopolimer erősítőanyagénál lényegesen alacsonyabb. A kompozitokat extrúziós impregnálással készült előgyártmány fröccsöntésével, valamint a mátrix szövetre történő ráfröcssöntésével állítottuk elő. Az impregnált előgyártmányból készült kompozit statikus és dinamikus tulajdonságai nem kielégítőek, ezért a két módszer közül az utóbbi bizonyult ígéretesebbnek
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Fröccsöntött amorf poli-alfa-olefin mátrixú önerősített kompozit fejlesztése: Development of injection molded all-polypropylene composites with amorphous poly-alpha-olefin matrix
Erdélyi Magyar Műszaki Tudományos Társaság (EMT) - Gépészeti Szakosztálya, 2020Co-Authors: Varga, László József, BÁrÁny TamásAbstract:The goal of this study is to produce injection molded all-polypropylene composites at a low injection temperature. As a matrix, we used an amorphous poly-alpha-olefin-based melt-adhesive, as its melting temperature is significantly lower than the melting temperature of the polypropylene homopolymer reinforcement. The composites were produced by injection molding of an impregnated pre-product, and by overmolding of the reinforcing fabric. The composites made of the impregnated pre-product showed unsatisfactory mechanical properties, so the latter method seems to be more promising. Kivonat A kutatás célja alacsony hőmérsékleten fröccsönthető önerősített kompozitok kifejlesztése. Mátrixként amorf poli-alfa-olefin tartalmú ömledékragasztót használtunk, amelynek az olvadási hőmérséklete a polipropilén homopolimer erősítőanyagénál lényegesen alacsonyabb. A kompozitokat extrúziós impregnálással készült előgyártmány fröccsöntésével, valamint a mátrix szövetre történő ráfröcssöntésével állítottuk elő. Az impregnált előgyártmányból készült kompozit statikus és dinamikus tulajdonságai nem kielégítőek, ezért a két módszer közül az utóbbi bizonyult ígéretesebbnek
Varga, László József - One of the best experts on this subject based on the ideXlab platform.
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Fröccsöntött amorf poli-alfa-olefin mátrixú önerősített kompozit fejlesztése
Erdélyi Magyar Műszaki Tudományos Társaság (EMT) - Gépészeti Szakosztálya, 2020Co-Authors: Varga, László József, BÁrÁny TamásAbstract:The goal of this study is to produce injection molded all-polypropylene composites at a low injection temperature. As a matrix, we used an amorphous poly-alpha-olefin-based melt-adhesive, as its melting temperature is significantly lower than the melting temperature of the polypropylene homopolymer reinforcement. The composites were produced by injection molding of an impregnated pre-product, and by overmolding of the reinforcing fabric. The composites made of the impregnated pre-product showed unsatisfactory mechanical properties, so the latter method seems to be more promising. Kivonat A kutatás célja alacsony hőmérsékleten fröccsönthető önerősített kompozitok kifejlesztése. Mátrixként amorf poli-alfa-olefin tartalmú ömledékragasztót használtunk, amelynek az olvadási hőmérséklete a polipropilén homopolimer erősítőanyagénál lényegesen alacsonyabb. A kompozitokat extrúziós impregnálással készült előgyártmány fröccsöntésével, valamint a mátrix szövetre történő ráfröcssöntésével állítottuk elő. Az impregnált előgyártmányból készült kompozit statikus és dinamikus tulajdonságai nem kielégítőek, ezért a két módszer közül az utóbbi bizonyult ígéretesebbnek
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Fröccsöntött amorf poli-alfa-olefin mátrixú önerősített kompozit fejlesztése: Development of injection molded all-polypropylene composites with amorphous poly-alpha-olefin matrix
Erdélyi Magyar Műszaki Tudományos Társaság (EMT) - Gépészeti Szakosztálya, 2020Co-Authors: Varga, László József, BÁrÁny TamásAbstract:The goal of this study is to produce injection molded all-polypropylene composites at a low injection temperature. As a matrix, we used an amorphous poly-alpha-olefin-based melt-adhesive, as its melting temperature is significantly lower than the melting temperature of the polypropylene homopolymer reinforcement. The composites were produced by injection molding of an impregnated pre-product, and by overmolding of the reinforcing fabric. The composites made of the impregnated pre-product showed unsatisfactory mechanical properties, so the latter method seems to be more promising. Kivonat A kutatás célja alacsony hőmérsékleten fröccsönthető önerősített kompozitok kifejlesztése. Mátrixként amorf poli-alfa-olefin tartalmú ömledékragasztót használtunk, amelynek az olvadási hőmérséklete a polipropilén homopolimer erősítőanyagénál lényegesen alacsonyabb. A kompozitokat extrúziós impregnálással készült előgyártmány fröccsöntésével, valamint a mátrix szövetre történő ráfröcssöntésével állítottuk elő. Az impregnált előgyártmányból készült kompozit statikus és dinamikus tulajdonságai nem kielégítőek, ezért a két módszer közül az utóbbi bizonyult ígéretesebbnek
Taisen Iguchi - One of the best experts on this subject based on the ideXlab platform.
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neverland regulates embryonic Moltings through the regulation of ecdysteroid synthesis in the water flea daphnia magna and may thus act as a target for chemical disruption of Molting
Journal of Applied Toxicology, 2016Co-Authors: Eri Sumiya, Yukiko Ogino, Kenji Toyota, Hitoshi Miyakawa, Shinichi Miyagawa, Taisen IguchiAbstract:Embryo development in arthropods is accompanied by a series of Moltings. A cladoceran crustacean Daphnia magna molts three times before reaching first instar neonate during embryogenesis. Previous studies argued ecdysteroids might regulate D. magna embryogenesis. However, no direct evidence between innate ecdysteroids fluctuation and functions has been forthcoming. Recently, we identified genes involved in ecdysteroid synthesis called, neverland (neverland1 and neverland 2) and shade and in the ecdysteroid degradation (Cyp18a1). To understand the physiological roles of ecdysteroids in D. magna embryos, we performed expression and functional analyzes of those genes. Examining innate ecdysteroids titer during embryogenesis showed two surges of ecdysteroids titer at 41 and 61 h after oviposition. The first and second embryonic Moltings occurred at each ecdysteroid surge. Expression of neverland1 and shade began to increase before the first peak in ecdysteroid. Knockdown of neverland1 or shade by RNAi technique caused defects in embryonic Moltings and subsequent development. The ecdysteroids titer seemingly decreased in nvd1-knowckdown embryos. Knockdown of Cyp18a1 resulted in early embryonic lethality before the first Molting. Our in situ hybridization analysis revealed that nvd1 was prominently expressed in embryonic gut epithelium suggesting the site for an initial step of ecdysteroidgenesis, a conversion of cholesterol to 7-dehydrocholesterol and possibly for ecdysone production. Taken together, de novo ecdysteroid synthesis by nvd1 in the gut epithelial cells stimulates Molting, which is indispensable for D. magna embryo development. These findings identify neverland as a possible target for chemicals, including various pesticides that are known to disrupt Molting, development and reproduction. Copyright © 2016 John Wiley & Sons, Ltd.
Dongkook Kim - One of the best experts on this subject based on the ideXlab platform.
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preparation and characterization of shape memory polymer networks based on carboxylated telechelic poly ɛ caprolactone epoxidized natural rubber blends
Journal of Industrial and Engineering Chemistry, 2010Co-Authors: Youngwook Chang, Joonphil Eom, Jaegu Kim, Heetaik Kim, Dongkook KimAbstract:Abstract Shape memory polymer networks were prepared from blends of end-carboxylated telechelic poly(ɛ-caprolactone) (XPCL) and epoxidized natural rubber (ENR). The XPCL/ENR blends can form cross linked structure via interchain reaction between the reactive groups of each polymer during molding at high temperature. Degree of crosslinking of the blend network and their thermomechanical properties were characterized by gel content measurement, DSC and DMA. We found that the degree of crosslinking and crystalline melting transition temperatures was dependent upon the blend compositions as well as the molecular weight of the XPCL segment in the blends. The blends showed a good shape memory behavior such as good shape fixity as well as a high final recovery rate when they exhibit crystalline melting transition with a sufficiently high degree of crosslinking. And the response temperature of the recovery was well matched with Tm of the samples.
Abu Bakar Sulong - One of the best experts on this subject based on the ideXlab platform.
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analysis of warpage and shrinkage properties of injection molded micro gears polymer composites using numerical simulations assisted by the taguchi method
Materials & Design, 2012Co-Authors: Eghbal Hakimian, Abu Bakar SulongAbstract:Abstract Microgears containing four cavities and consisting of three different types of thermoplastic materials, namely, the amorphous polycarbonate/acrylonitrile–butadiene–styrene blend (PC/ABS), amorphous polyphenylene–ether/polystyrene (PPE/PS), and crystalline polyoxymethylene (POM) filled with glass fibers were analyzed. Molding parameters such as packing time, cooling temperature, molding and melting temperatures, packing and injection pressures, and fiberglass percentages are the most important factors affecting warpage and shrinkage. Three factors and their interactions were investigated in this case study. The effects of the injection parameters on warpage and shrinkage at different fiberglass percentages and cooling temperatures were analyzed according to the Taguchi method. The minimum values for warpage (0.0051 mm) and shrinkage (2.2886%) were derived from the PC/ABS and PPE/PS composites, respectively. Process efficiency predictions and conformational analyses of the optimal levels for each injection molding parameter were conducted to demonstrate the advantages of the Taguchi analytical method. The highest improvement percentages in the shrinkage and warpage analyses were obtained from the PPE/PS and the PC/ABS, respectively. PPE/PS was the best polymer composite by shrinkage analysis because of its molecular structure and minimum temperature at the flow front range, while the PC/ABS behaved the best in the warpage analysis.