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Yoshihiko Hangai - One of the best experts on this subject based on the ideXlab platform.
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functionally graded aluminum foam consisting of dissimilar aluminum alloys fabricated by sintering and Dissolution Process
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2017Co-Authors: Yoshihiko Hangai, Tomoaki Morita, Takao UtsunomiyaAbstract:Abstract Functionally graded (FG) aluminum (Al) foam, which consists of multilayers of different Al foams, is expected to exhibit higher functionality than ordinary uniform Al foam. In this study, uniform Al foams and two kinds of two-layered FG Al foams with different types of Al were fabricated by a sintering and Dissolution Process. From X-ray computed tomography (CT) inspection of the obtained foams, it was confirmed that NaCl was completely removed from the foams by Dissolution. In addition, the FG Al foams in each layer had almost constant porosity (NaCl volume fraction, Vf) with seamless bonding between the layers. From the static compression tests of uniform foams, it was shown that the compression properties can be controlled by varying the type of Al, which is a similar tendency to the mechanical properties of the bulk materials. In addition, the compression properties can be controlled by varying Vf, regardless of the type of Al. From the static compression tests of FG Al foams, the foams exhibited multiple compression properties corresponding to the deformation of each layer for various Vf and different types of Al, which were similar to those of the corresponding uniform foams. In addition, the width of the plateau regions of FG Al foams can be controlled by controlling the height ratio between the layers. The advantage of varying the type of Al is that the mechanical properties of foams can be controlled without changing their geometric structures. Therefore, FG Al foams with various Vf and types of Al are expected to enable the optimum design of foams used for structural materials.
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large scale aluminum foam plate fabricated by enhanced friction powder compaction Process based on sintering and Dissolution Process
Journal of Materials Processing Technology, 2014Co-Authors: Yoshihiko Hangai, Kousuke Zushida, Osamu Kuwazuru, Nobuhiro YoshikawaAbstract:Abstract An enhanced friction powder compaction (FPC) Process was proposed for fabricating a large plate of aluminum foam by the sintering and Dissolution Process. In this Process, the rotating tool plunged into the die filled with a powder mixture of aluminum and NaCl during the FPC Process was made to traverse perpendicularly to the direction of plunging as in the case of friction stir welding. In the enhanced FPC Process, no external heat source, such as an electric furnace or a spark plasma sintering, was necessary for fabricating aluminum foam, except for the friction heat generated by traversing the rotating tool. It was found that a long plate of aluminum foam can be fabricated with a length equal to the tool traversing length. By X-ray computed tomography (CT) and scanning electron microscopy (SEM) observations of the pore structures of the fabricated aluminum foam, it was found that the entire sample had a pore structures that was similar to the NaCl morphology, regardless of the position along the traversing direction. The fabricated aluminum foam had a similar stress–strain curve to that of aluminum foam fabricated by spark plasma sintering and exhibited ductile fracture. This is considered to be attributed to the good bonding between aluminum particles in the entire sample. The fabricated aluminum foam exhibited almost the same plateau stress regardless of the position along the traversing direction.
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friction powder compaction Process for fabricating open celled cu foam by sintering Dissolution Process route using nacl space holder
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2013Co-Authors: Yoshihiko Hangai, Kousuke Zushida, Rintaro Ueji, Osamu Kuwazuru, Hidetoshi Fujii, Nobuhiro YoshikawaAbstract:Abstract Open-celled metal foams have received considerable attention in various fields and are expected to be used as engineering materials where heat exchange, sound absorption and filtration are required. In this study, Cu foam specimens with NaCl volume fractions of 60%, 70% and 80% were successfully fabricated by the friction powder compaction (FPC) Process with the sintering and Dissolution Process (SDP) using NaCl as space holders. In the FPC Process, no external heat source was used for fabricating Cu foam except for the friction heat generated by the rotating tool plunged into the die and powders. From the X-ray CT and SEM observation of the pore structures of the fabricated Cu foam, it was found that almost the entire specimen had a pore structure similar to the NaCl morphology, regardless of the NaCl volume fraction. This is mainly because the sintering Process for Cu particles in the FPC Process was achieved at a temperature lower than the melting point of NaCl. From compression tests of the fabricated Cu foam, Cu foam exhibited ductile fracture regardless of its NaCl volume fraction, which is considered to be attributed to the good bonding between Cu particles. The plateau stress and energy absorption decreased with increasing NaCl volume fraction, indicating strong relationships between them. The Cu foam with the highest energy absorption per unit volume up to the specific stress changed from the high-NaCl-volume-fraction Cu foam to the low-NaCl-volume-fraction Cu foam with increasing compression stress. Consequently, it was shown that the mechanical properties of Cu foam can be controlled by adjusting the volume fraction of NaCl.
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Friction Powder Compaction for Fabrication of Open-Cell Aluminum Foam by the Sintering and Dissolution Process Route
Metallurgical and Materials Transactions A, 2012Co-Authors: Yoshihiko Hangai, Hiroaki Yoshida, Nobuhiro YoshikawaAbstract:A new friction powder compaction (FPC) Process by the sintering and Dissolution Process (SDP) route for fabricating open-cell aluminum (Al) foam, which requires no external heat sources, was developed. Foams with porosities of 74 and 83 pct were successfully fabricated and their compressive responses were investigated. The sintered mixture during the removal Process was observed nondestructively by X-ray computed tomography (CT) to reveal the progress of the removal of soluble particles and to confirm that they were completely dissolved.
Nobuhiro Yoshikawa - One of the best experts on this subject based on the ideXlab platform.
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large scale aluminum foam plate fabricated by enhanced friction powder compaction Process based on sintering and Dissolution Process
Journal of Materials Processing Technology, 2014Co-Authors: Yoshihiko Hangai, Kousuke Zushida, Osamu Kuwazuru, Nobuhiro YoshikawaAbstract:Abstract An enhanced friction powder compaction (FPC) Process was proposed for fabricating a large plate of aluminum foam by the sintering and Dissolution Process. In this Process, the rotating tool plunged into the die filled with a powder mixture of aluminum and NaCl during the FPC Process was made to traverse perpendicularly to the direction of plunging as in the case of friction stir welding. In the enhanced FPC Process, no external heat source, such as an electric furnace or a spark plasma sintering, was necessary for fabricating aluminum foam, except for the friction heat generated by traversing the rotating tool. It was found that a long plate of aluminum foam can be fabricated with a length equal to the tool traversing length. By X-ray computed tomography (CT) and scanning electron microscopy (SEM) observations of the pore structures of the fabricated aluminum foam, it was found that the entire sample had a pore structures that was similar to the NaCl morphology, regardless of the position along the traversing direction. The fabricated aluminum foam had a similar stress–strain curve to that of aluminum foam fabricated by spark plasma sintering and exhibited ductile fracture. This is considered to be attributed to the good bonding between aluminum particles in the entire sample. The fabricated aluminum foam exhibited almost the same plateau stress regardless of the position along the traversing direction.
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friction powder compaction Process for fabricating open celled cu foam by sintering Dissolution Process route using nacl space holder
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2013Co-Authors: Yoshihiko Hangai, Kousuke Zushida, Rintaro Ueji, Osamu Kuwazuru, Hidetoshi Fujii, Nobuhiro YoshikawaAbstract:Abstract Open-celled metal foams have received considerable attention in various fields and are expected to be used as engineering materials where heat exchange, sound absorption and filtration are required. In this study, Cu foam specimens with NaCl volume fractions of 60%, 70% and 80% were successfully fabricated by the friction powder compaction (FPC) Process with the sintering and Dissolution Process (SDP) using NaCl as space holders. In the FPC Process, no external heat source was used for fabricating Cu foam except for the friction heat generated by the rotating tool plunged into the die and powders. From the X-ray CT and SEM observation of the pore structures of the fabricated Cu foam, it was found that almost the entire specimen had a pore structure similar to the NaCl morphology, regardless of the NaCl volume fraction. This is mainly because the sintering Process for Cu particles in the FPC Process was achieved at a temperature lower than the melting point of NaCl. From compression tests of the fabricated Cu foam, Cu foam exhibited ductile fracture regardless of its NaCl volume fraction, which is considered to be attributed to the good bonding between Cu particles. The plateau stress and energy absorption decreased with increasing NaCl volume fraction, indicating strong relationships between them. The Cu foam with the highest energy absorption per unit volume up to the specific stress changed from the high-NaCl-volume-fraction Cu foam to the low-NaCl-volume-fraction Cu foam with increasing compression stress. Consequently, it was shown that the mechanical properties of Cu foam can be controlled by adjusting the volume fraction of NaCl.
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Friction Powder Compaction for Fabrication of Open-Cell Aluminum Foam by the Sintering and Dissolution Process Route
Metallurgical and Materials Transactions A, 2012Co-Authors: Yoshihiko Hangai, Hiroaki Yoshida, Nobuhiro YoshikawaAbstract:A new friction powder compaction (FPC) Process by the sintering and Dissolution Process (SDP) route for fabricating open-cell aluminum (Al) foam, which requires no external heat sources, was developed. Foams with porosities of 74 and 83 pct were successfully fabricated and their compressive responses were investigated. The sintered mixture during the removal Process was observed nondestructively by X-ray computed tomography (CT) to reveal the progress of the removal of soluble particles and to confirm that they were completely dissolved.
Xue-hong Zhang - One of the best experts on this subject based on the ideXlab platform.
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solubility of rutaecarpine and evodiamine in ethanol water mixed solvents at temperatures from 288 2 to 328 2 k
The Journal of Chemical Thermodynamics, 2015Co-Authors: Xuemeng Yang, Xiaokang Xu, Xue-hong ZhangAbstract:Abstract The solubility of rutaecarpine and evodiamine was measured in (ethanol + water) mixed solvents with different values of mole fraction ethanol from (φ = 0.30 to 0.80) over the temperature range of (T = 288.2, 298.2, 308.2, 318.2 and 328.2) K. With increasing temperature and mole fraction ethanol, the solubility of rutaecarpine and evodiamine increased. The experimental solubility values were well correlated by the modified Apelblat equation, simplified thermodynamic equation and semi-empirical Buchowski–Ksiazczak λh equation. The correlated results by the modified Apelblat equation were better than those by other two equations. The enthalpy of Dissolution (ΔdisHo) and entropy of Dissolution (ΔdisSo) of rutaecarpine and evodiamine during the Dissolution Process in (ethanol + water) mixed solvents were calculated by the van’t Hoff equation. The results indicate that the Dissolution Process is endothermic and entropy-driven.
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solubilities of betulin and betulinic acid in sodium hydroxide aqueous solutions of varied mole fraction at temperatures from 283 2k to 323 2k
The Journal of Chemical Thermodynamics, 2013Co-Authors: Fatian Song, Xue-hong ZhangAbstract:The solubilities of betulin and betulinic acid were measured at varied values of mole fraction of sodium hydroxide aqueous solutions at a series of temperature (283.2, 293.2, 303.2, 313.2, and 323.2) K. They increase with the increase of temperature. Furthermore, the solubility of betulinic acid has a positive correlation with the mole fraction of sodium hydroxide aqueous solutions, and so is that of the betulin. The experimental solubility resuls are well correlated by the modified Apelblat equation. The enthalpy and entropy of betulin and betulinic acid during the Dissolution Process in sodium hydroxide aqueous solutions are calculated with the van’t Hoff equation. The results indicate that the Dissolution Process is endothermal reaction that is driven by entropy.
Heike Lorenz - One of the best experts on this subject based on the ideXlab platform.
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resolution of racemic guaifenesin applying a coupled preferential crystallization selective Dissolution Process rational Process development
Crystal Growth & Design, 2019Co-Authors: Erik Temmel, Matthias Eicke, Francesca Cascella, Andreas Seidelmorgenstern, Heike LorenzAbstract:Preferential crystallization is a cost efficient method to provide pure enantiomers from a racemic mixture of a conglomerate forming system. Exploiting small amounts of pure crystals of both enantiomers, several batch or continuous Processes were developed, capable of providing both species. However, an intermediate production step has to be used when pure enantiomers are not available. In such cases, partially selective synthesis, chromatography, or crystallization Processes utilizing chiral auxiliaries have to be used to provide the initial seed material. Recently, it was shown that a coupled Preferential Crystallization-selective Dissolution Process (CPCD) in two coupled crystallizers can be applied if at least one pure enantiomer is available to produce both antipodes within one batch. The corresponding Process is carried out in one reactor (crystallization tank) by seeding a racemic supersaturated solution with the available enantiomer at a certain temperature. The second reactor (Dissolution tank) c...
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Resolution of Racemic Guaifenesin Applying a Coupled Preferential Crystallization-Selective Dissolution Process: Rational Process Development
2019Co-Authors: Erik Temmel, Matthias Eicke, Francesca Cascella, Andreas Seidel-morgenstern, Heike LorenzAbstract:Preferential crystallization is a cost efficient method to provide pure enantiomers from a racemic mixture of a conglomerate forming system. Exploiting small amounts of pure crystals of both enantiomers, several batch or continuous Processes were developed, capable of providing both species. However, an intermediate production step has to be used when pure enantiomers are not available. In such cases, partially selective synthesis, chromatography, or crystallization Processes utilizing chiral auxiliaries have to be used to provide the initial seed material. Recently, it was shown that a coupled Preferential Crystallization-selective Dissolution Process (CPCD) in two coupled crystallizers can be applied if at least one pure enantiomer is available to produce both antipodes within one batch. The corresponding Process is carried out in one reactor (crystallization tank) by seeding a racemic supersaturated solution with the available enantiomer at a certain temperature. The second reactor (Dissolution tank) contains a saturated racemic suspension at a higher temperature. Both reactors are coupled via the fluid phase, allowing for a selective Dissolution of the preferentially crystallizing enantiomer from the solid racemic feed provided in the Dissolution vessel. The Dissolution and crystallization Processes continue until the solid racemic material is completely resolved and becomes enantiopure. At this point, both enantiomers can be harvested in their pure crystalline form. For a specific pharmaceutically relevant case study, a rational Process design and the applied empirical optimization procedure will be described. The achieved productivities after optimization show the great potential of this approach also for industrial applications. Also, a strategy to control this Process based on inline turbidity measurement will be presented
Andreas Seidelmorgenstern - One of the best experts on this subject based on the ideXlab platform.
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resolution of racemic guaifenesin applying a coupled preferential crystallization selective Dissolution Process rational Process development
Crystal Growth & Design, 2019Co-Authors: Erik Temmel, Matthias Eicke, Francesca Cascella, Andreas Seidelmorgenstern, Heike LorenzAbstract:Preferential crystallization is a cost efficient method to provide pure enantiomers from a racemic mixture of a conglomerate forming system. Exploiting small amounts of pure crystals of both enantiomers, several batch or continuous Processes were developed, capable of providing both species. However, an intermediate production step has to be used when pure enantiomers are not available. In such cases, partially selective synthesis, chromatography, or crystallization Processes utilizing chiral auxiliaries have to be used to provide the initial seed material. Recently, it was shown that a coupled Preferential Crystallization-selective Dissolution Process (CPCD) in two coupled crystallizers can be applied if at least one pure enantiomer is available to produce both antipodes within one batch. The corresponding Process is carried out in one reactor (crystallization tank) by seeding a racemic supersaturated solution with the available enantiomer at a certain temperature. The second reactor (Dissolution tank) c...