The Experts below are selected from a list of 30165 Experts worldwide ranked by ideXlab platform
Xiaojun Shen - One of the best experts on this subject based on the ideXlab platform.
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the Reinforcing Effect of oriented graphene on the interlaminar shear strength of carbon fabric epoxy composites
Materials & Design, 2020Co-Authors: Xiaojun Shen, Chenyang Dang, Bolin Tang, Xiaohui Yang, Jingjing Lu, Tongtong Zhang, K FriedrichAbstract:Abstract In this study, nano Fe3O4 functionalized graphene oxide (Fe3O4@GO) was employed to enhance the interlaminar shear strength (ILSS) of carbon fabric/epoxy (CF/EP) composites. The composite was fabricated via a vacuum-assisted resin transfer molding process under a magnetic field. The microstructure and reinforcement mechanism of the CF/EP composite was further investigated. The results indicate that the Fe3O4@GO can increase the ILSS of the CF/EP composite by 12.9%, and it can further enhance it to 41% under the magnetic field orientation. Furthermore, it was observed that the oriented Fe3O4@GO can also improve the flexural strength and tensile strength of the CF/EP composite by 29.7% and 40.9%, respectively. The main reason is that the oriented GO arrangement is better ordered and thus can withstand more lateral loads inside the composite.
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the Reinforcing Effect of graphene nanosheets on the cryogenic mechanical properties of epoxy resins
Composites Science and Technology, 2012Co-Authors: Xiaojun Shen, Yu Liu, Hongmei Xiao, Qingping FengAbstract:Abstract The Reinforcing Effect of graphene in enhancing the cryogenic tensile and impact properties of epoxy composites is examined at a weight fraction of 0.05–0.50%. The micro-structure and cryogenic mechanical properties of the graphene/epoxy composites are investigated using scanning electron microscopy, transmission electron microscopy, small-angle X-ray scattering and mechanical testing techniques. The results show that the graphene dispersion in the epoxy matrix is good at low contents while its aggregation takes place and becomes severer as its content increases. And the cryogenic tensile and impact strength at liquid nitrogen temperature (77 K) of the composites are Effectively improved by the graphene addition at proper contents. The cryogenic Young’s modulus increases almost linearly with increasing the graphene content. Moreover, the results for the mechanical properties at room temperature (298 K) of the graphene/epoxy composites are also presented for the purpose of comparison.
Kristiina Oksman - One of the best experts on this subject based on the ideXlab platform.
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dispersion and Reinforcing Effect of carrot nanofibers on biopolyurethane foams
Materials & Design, 2016Co-Authors: Xiaojian Zhou, Kristiina Oksman, Jatin Sethi, Shiyu Geng, Linn Berglund, Nikolina Frisk, Yvonne Aitomaki, Mohini SainAbstract:Abstract In this study, carrot nanofibers (CNF) were used to enhance the performance of biobased castor oil polyol polyurethane nanocomposite foams. A method of dispersing CNF in the polyol was developed and the foam characteristics and CNF Reinforcing Effect were studied. Co-solvent-assisted mixing resulted in well-dispersed CNF in the polyol, and foams with 0.25, 0.5 and 1 phr CNF content were prepared. The reinforced nanocomposite foams displayed a narrow cell size distribution and the compressive strength and modulus were significantly elevated and the best compressive strength and modulus were reached with 0.5 phr CNF. Similarly, the modulus of the solid material was also significantly increased based on theoretical calculations. When comparing the foam performance, compressive strength and stiffness as a function of the density, the nanocomposite foams performs as commercial rigid PU foam with a closed cell structure. These results are very promising and we believe that these foams are excellent core materials for lightweight sandwich composites.
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Reinforcing Effect of carboxymethylated nanofibrillated cellulose powder on hydroxypropyl cellulose
Cellulose, 2010Co-Authors: Christian Eyholzer, F. Lopez-suevos, Philippe Tingaut, Tanja Zimmermann, Kristiina OksmanAbstract:Bionanocomposites of hydroxypropyl cellulose (HPC) and nanofibrillated cellulose (NFC) were prepared by solution casting. The various NFC were in form of powders and were prepared from refined, bleached beech pulp (RBP) by mechanical disintegration, optionally combined with a pre- or post mechanical carboxymethylation. Dynamic mechanical analysis (DMA) and tensile tests were performed to compare the Reinforcing Effects of the NFC powders to those of their never-dried analogues. For unmodified NFC powders an inferior Reinforcing potential in HPC was observed that was ascribed to severe hornification and reagglomeration of NFC. In contrast, the composites with carboxymethylated NFC showed similar behaviors, regardless of the NFC suspensions being dried or not prior to composite preparation. SEM characterization confirmed a homogeneous dispersion of dried, carboxymethylated NFC within the HPC matrix. These results clearly demonstrate that drying of carboxymethylated NFC to a powder does not decrease its Reinforcing potential in (bio)nanocomposites.
Sherif Araby - One of the best experts on this subject based on the ideXlab platform.
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electrically and thermally conductive elastomer graphene nanocomposites by solution mixing
Polymer, 2014Co-Authors: Sherif Araby, Qingshi Meng, Liqun Zhang, Hailan Kang, Peter Majewski, Youhong TangAbstract:Abstract The greatest challenge in developing polymer/graphene nanocomposites is to prevent graphene layers stacking; in this respect, we found Effective solution-mixing polymers with cost-Effective graphene of hydrophobic surface. Since graphene oxide is hydrophilic and in need of reduction, highly conducing graphene platelets (GnPs) of ∼3 nm in thickness were selected to solution-mix with a commonly used elastomer – styrene–butadiene rubber (SBR). A percolation threshold of electrical conductivity was observed at 5.3 vol% of GnPs, and the SBR thermal conductivity enhanced three times at 24 vol%. Tensile strength, Young's modulus and tear strength were improved by 413%, 782% and 709%, respectively, at 16.7 vol%. Payne Effect, an important design criteria for elastomers used in dynamic loading environment, was also investigated. The comparison of solution mixing with melt compounding, where the same starting materials were used, demonstrated that solution mixing is more Effective in promoting the Reinforcing Effect of GnPs, since it provides more interlayer spacing for elastomer molecules intercalating and retains the high aspect ratio of GnPs leading to filler–filler network at a low volume fraction. We also compared the Reinforcing Effect of GnPs with those of carbon black and carbon nanotubes.
William J Mcbride - One of the best experts on this subject based on the ideXlab platform.
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gabaa receptor blockade in the anterior ventral tegmental area increases extracellular levels of dopamine in the nucleus accumbens of rats
Journal of Neurochemistry, 2002Co-Authors: Satoshi Ikemoto, Robert R Kohl, William J McbrideAbstract:Previously, it was shown that microinfusion of the GABA(A) antagonist picrotoxin into the anterior ventral tegmental area (VTA) is Reinforcing. It was hypothesized that this Reinforcing Effect of picrotoxin in the anterior VTA is mediated, at least in part, by the activation of the mesoaccumbens dopamine (DA) system. The objective of the present study was to determine if blockade of GABA(A) receptors in the anterior VTA can increase extracellular levels of DA in the nucleus accumbens (ACB), using an in vivo microdialysis technique in freely moving rats. Concentrations of picrotoxin (40, 80, and 160 microM) that had previously been shown to produce a Reinforcing Effect increased the extracellular levels of DA and its major metabolites in the ACB. The increased extracellular DA levels induced by intra-VTA injection of picrotoxin was markedly attenuated by coadministration with the GABA(A) agonist muscimol, whereas intra-VTA injection of muscimol alone did not have an apparent Effect on extracellular DA levels in the ACB. Microinjection of another GABA(A) antagonist, bicuculline, into the anterior VTA also increased the extracellular release of DA in the ACB. These results suggest that DA neurons projecting from the anterior VTA to the ACB are tonically inhibited by GABA through its actions at the GABA(A) receptors.
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self infusion of gaba a antagonists directly into the ventral tegmental area and adjacent regions
Behavioral Neuroscience, 1997Co-Authors: Satoshi Ikemoto, James M Murphy, William J McbrideAbstract:This study used an intracerebral self-administration paradigm in rats to determine if blockade of GABA A receptors in the ventral tegmental area (VTA) has a Reinforcing Effect. Rats quickly learned to self-infuse a picrotoxin solution into the anterior VTA; rats discriminated the lever that produced picrotoxin infusions from the lever without consequences; and when the response requirement was increased, rats increased response levels for picrotoxin infusion. The Reinforcing Effect of picrotoxin was site-specific: Anterior VTA regions supported vigorous self-infusions, but not the posterior VTA, substantia nigra, or lateral hypothalamus. Muscimol, a GABA A agonist, disrupted picrotoxin self-infusion, but bicuculline, a GABA A antagonist, was self-infused into the VTA. The results suggest that blockade of GABA A receptors in the anterior VTA is Reinforcing and that functional organization of the GABA systems within the VTA is heterogeneous.
Hiroshi Shimizu - One of the best experts on this subject based on the ideXlab platform.
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Reinforcing Effect of glass fiber-reinforced composite reinforcement on flexural strength at proportional limit of a repaired denture base resin
Acta biomaterialia odontologica Scandinavica, 2015Co-Authors: Kaneyoshi Yoshida, Hirono Sasaki, Tomohiro Kawaguchi, Ippei Hamanaka, Yutaka Takahashi, Hiroshi ShimizuAbstract:AbstractObjective: This study evaluated the Reinforcing Effect of glass fiber-reinforced composite (FRC) reinforcement on flexural strength at the proportional limit (FS-PL) of a repaired denture base resin.Materials and methods: Repaired denture base resins reinforced with metal and with FRC reinforcement, and that without reinforcement were tested. The ultimate flexural strength, the FS-PL and the elastic modulus of repaired denture base resins were tested. The joint efficiency (times) of the repaired denture base resins on the intact denture base resin was evaluated.Results: The repaired denture base resins reinforced with metal reinforcement and with FRC reinforcement had significantly higher ultimate flexural strength than the repaired denture base resin without reinforcement (p 0.05). The FS-PL of a repaired denture base resin reinforced with the FRC reinforcement was similar to that with the metal reinforcement (p > 0.05), and these ...
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Reinforcing Effect of glass fiber reinforced composite reinforcement on flexural strength at proportional limit of a repaired denture base resin
Acta biomaterialia odontologica Scandinavica, 2015Co-Authors: Kaneyoshi Yoshida, Hirono Sasaki, Tomohiro Kawaguchi, Ippei Hamanaka, Yutaka Takahashi, Hiroshi ShimizuAbstract:Objective: This study evaluated the Reinforcing Effect of glass fiber-reinforced composite (FRC) reinforcement on flexural strength at the proportional limit (FS-PL) of a repaired denture base resin. Materials and methods: Repaired denture base resins reinforced with metal and with FRC reinforcement, and that without reinforcement were tested. The ultimate flexural strength, the FS-PL and the elastic modulus of repaired denture base resins were tested. The joint efficiency (times) of the repaired denture base resins on the intact denture base resin was evaluated. Results: The repaired denture base resins reinforced with metal reinforcement and with FRC reinforcement had significantly higher ultimate flexural strength than the repaired denture base resin without reinforcement (p 0.05). The FS-PL of a repaired denture base resin reinforced with the FRC reinforcement was similar to that with the metal reinforcement (p > 0.05), and these were significantly higher than the FS-PL of a repaired denture base resin without reinforcement (p < 0.05). The elastic modulus of the repaired denture base resin reinforced with the FRC reinforcement was significantly lower than that with metal reinforcement (p < 0.05) and was significantly higher than that without reinforcement (p < 0.05). The joint efficiency of the FRC reinforced specimen was 0.98. Conclusion: The FRC reinforcement had a Reinforcing Effect on the FS-PL of a repaired denture base resin.
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Reinforcing Effect of glass-fiber-reinforced composite on flexural strength at the proportional limit of denture base resin
Acta Odontologica Scandinavica, 2009Co-Authors: Fumitake Tsue, Yutaka Takahashi, Hiroshi ShimizuAbstract:Objective. To evaluate the Reinforcing Effect of fiber-reinforced composite (FRC) on flexural strengths at the proportional limit (FS-PL) of a denture base resin. Material and methods. Bar-shaped acrylic resin specimens and maxillary acrylic resin complete denture specimens were fabricated. The FS-PL of the reinforced bar-shaped specimens was tested. Novel FRC, FibreKor, Remanium, Palatal Bar Wire, and Clasp-Wire were used as Reinforcing materials. Likewise, the compressive strength at the proportional limit (CS-PL) of the reinforced maxillary denture specimens was tested. Results. The FS-PL of the bar-shaped specimens reinforced with the FRCs was significantly higher than that of the unreinforced specimenswithouwi. The FS-PL of the bar-shaped specimens reinforced with the 1.0-mm-thick FRC was similar to the FS-PL of specimens reinforced with Remanium or Palatal Bar Wire. The FS-PL of specimens reinforced with the 1.5-mm-thick FRC was significantly higher than with the metal-Reinforcing materials. The rei...
