Since weldline in plastic injection molding (PIM) has an influence on not only the strength but also the surface appearance of a plastic product, it is preferable to reduce it as much as possible for ...high product quality. High mold temperature will be valid to the weldline reduction, but long cycle time is required for cooling down the plastic product. Generally, short cycle time is required for high productivity and the cycle time should be minimized. The trade-off between product quality and productivity is always observed in the PIM. In this paper, the weldline reduction and the cycle time are considered for the product quality and the productivity. In particular, the variable injection velocity and the variable pressure profile are adopted for simultaneously improving them. Numerical simulation in the PIM is so intensive that a sequential approximate optimization (SAO) using a radial basis function (RBF) network is adopted to determine the optimal injection velocity and pressure profile with a small number of simulations. The trade-off between the weldline and the cycle time is clarified through the numerical result, and the experiment (GL100, Sodick) is carried out to confirm the validity of the proposed approach.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Rapid heat cycle molding (RHCM) that actively controls the mold temperature has attracted attention in plastic injection molding (PIM) for improving product surface quality. In the RHCM, the mold ...temperature profile plays a crucial role for producing products with high surface quality, but the profile as well as other process parameters is determined by the trial-and-error method. In this paper, weldline, clamping force, and cycle time are simultaneously minimized for the high product quality and the high productivity using the RHCM. The RHCM generally requires cycle time long, and then variable packing pressure profile that the packing pressure varies during PIM process is adopted to shorten the cycle time. The numerical simulation in the RHCM is computationally so expensive that sequential approximate optimization using radial basis function network is adopted to determine the optimal process parameters, and the pareto-frontier among weldline, clamping force and cycle time is identified. It is found from the numerical result that the optimal pressure profiles start with the low packing pressure and the high packing pressure is applied at the end of packing phase. The mold temperature increases due to the high packing pressure, and the high mold temperature makes the flow of melt plastic smooth. Consequently, the weldline reduction can be achieved. Based on the numerical result, the experiment using the PIM machine (MS100, Sodick) is carried out. Compared to the conventional PIM, the weldline reduction can be achieved with smaller clamping force.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
In plastic injection molding (PIM), the process parameters such as packing pressure, melt temperature, and cooling time should be adjusted and optimized for high product quality and high ...productivity. Warpage is one of the major defects in the PIM and should be minimized for high quality. Cycle time should be minimized for the high productivity. In addition to the warpage and the cycle time, clamping force affects the product both the quality and the productivity. Therefore, for the high product quality and the high productivity, it is important to minimize the warpage, the cycle time and the clamping force simultaneously. In this paper, a multi-objective optimization of process parameters in PIM for minimizing three objectives is performed. Numerical simulation in the PIM is generally so intensive that a sequential approximate optimization using radial basis function network is adopted to determine the optimal process parameters. The radar chart is used to perform the trade-off analysis among three objective functions. In addition, the better and worse solution are newly introduced for the trade-off analysis. It is found through the trade-off analysis that all objective functions of the conformal cooling channel are well improved in comparison with the ones of the conventional cooling channel. Therefore, 43% warpage reduction, 1,7% clamping force reduction, and 47% cycle time reduction can successfully be achieved using the conformal cooling channel. Based on the numerical result, the experiment using PIM machine (GL30-LP, Sodick) is carried out. The conformal cooling channel is developed by the metal 3D printer (OPM250L, Sodick). Through the numerical and experimental result, the validity of the proposed approach is examined.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Within no definite diuretic protocol for acute heart failure (AHF) patients and its variation in regional clinical guidelines, the latest national guidelines in Japan commends use of tolvaptan in ...diuretic-resistant patients. This study aimed to examine trends in tolvaptan usage and associated outcomes of AHF patients requiring hospitalization. Between April, 2018 and October, 2019, 1343 consecutive AHF patients (median 78 69-85 year-old) were enrolled in a prospective, multicenter registry in Japan. Trends over time in tolvaptan usage, along with the severity of heart failure status based on the Get With The Guideline-Heart Failure GWTG-HF risk score, and in-hospital outcomes were investigated. During the study period, tolvaptan usage has increased from 13.0 to 28.7% over time (p for trend = 0.07), and 49.4% started tolvaptan within 3 days after admission. The GWTG-HF risk score in the tolvaptan group has significantly decreased over time, while that in the non-tolvaptan group has unchanged. There were no differences in the in-hospital mortality rate between the patients with and without tolvaptan (6.7% vs. 5.8%). After revision of the Japanese clinical practice guidelines for AHF in March 2018, tolvaptan usage for AHF patients has steadily increased. However, in-hospital outcomes including mortality do not seem to be affected.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Black and electrically insulating coatings provide touch panel displays with a classic appearance. In this study, black and electrically insulating Ag–Fe2O3-based coatings were prepared using ...reactive magnetron sputtering, stainless steel and silver foil. The thin films prepared with oxygen introduction and no Ag foil showed blue light absorption and high electrical resistance, which are comparable to those of Fe2O3 single crystals. The optimal Ag foil size for maintaining a high electrical resistivity of 108 Ω·sq−1 was determined to be 54 mol%Ag in the film samples. Black and electrically insulating thin films composed of metallic Ag, amorphous Ag–Fe–O, and slightly crystallized Fe2O3 were prepared using 3.4 or 3.9 %O2. Metallic Ag segregated randomly in the high-refractive-index Fe2O3-based matrix, resulting in plasmonic absorption over a wide range of wavelengths centered in the red-wavelength region. At 3.9 %O2, a high sheet resistance of 108 Ω·sq−1 and strong visible absorption of 35.2 μm−1 (on average), slightly deviating by 2.4 μm−1 were simultaneously achieved by clear phase separation of the Ag grains and Fe2O3-based matrix. A clear phase separation mechanism based on thermodynamic nonequilibrium oxidation of the metallic Ag phase is proposed.
•Black insulative Ag–Fe2O3-based coating was prepared by sputtering from metal target.•Visible light absorption of 35 ± 2 μm−1 with resistance of 108 Ω·sq−1 was achieved.•Oxygen dissolution into metallic silver is important to be black and insulative.•Substitutional oxygen dissolution is experimentally and theoretically suggested.•This process has advantages for widespread applications in display industry.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Plastic injection molding (PIM) is a crucial processing technology for producing lightweight products. Process parameters such as melt temperature, packing pressure, and cooling time directly affect ...not only the product quality but also the productivity, and they are conventionally adjusted by the trial‐and‐error method. A constant packing pressure is conventionally used, but the multistage packing pressure profile recently attracts attention. However, the packing pressure profile is unknown in advance, and it is difficult to determine it through the trial‐and‐error method. In this paper, the multistage packing pressure profile as well as other process parameters so as to minimize the warpage and cycle time are determined by using computational intelligence and design optimization. It is found from the numerical result that 27% warpage and 50% cycle time reduction can be achieved, compared with ones using reference process parameters. In addition, it is clarified that clamping force can be reduced. This indicates that PIM using the optimal multi‐stage packing pressure profile can produce plastic product with small clamping force that makes the tool life long. Finally, the experiment using PIM machine equipped with servo controller (MS100, Sodick) is carried out to examine the effectiveness of the multistage packing pressure profile.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Strecker synthesis has long been considered one of the prebiotic reactions for the synthesis of α‐amino acids. However, the correlation between the origin of chirality and highly enantioenriched ...α‐amino acids through this method remains a puzzle. In the reaction, it may be conceivable that the handedness of amino acids has been determined at the formation stage of the chiral intermediate α‐aminonitrile, that is, the enantioselective addition of hydrogen cyanide to an imine. Herein, an enantiotopic crystal surface of an achiral imine acted as an origin of chirality for the enantioselective formation of α‐aminonitriles by the addition of HCN. In conjunction with the amplification of the enantiomeric excess and multiplication of enantioenriched aminonitrile, a large amount of near enantiopure α‐amino acids, with the l‐ and d‐handedness corresponding to the molecular orientation of the imine, is reported.
Face off: Correlation between the molecular orientation of an achiral imine and highly enantioenriched amino acids has been achieved for the Strecker synthesis. A highly enantioenriched aminonitrile was formed by the asymmetric addition of HCN at one surface of a single crystal of the imine, in combination with amplification of the ee value and multiplication of the enantioenriched product. Therefore, a possible entry for the origin of chiral amino acids has been found by using the Strecker reaction.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
We report the development of an open source “Debris Flow Simulator for Sabo” (DFSS). DFSS consists of three models corresponding to three geomorphological regions (mountain hillside slopes, ...mountain-to-plain river channels, and lower plains). A 2D rainfall-runoff (RR) model is adopted mainly for hillside slopes; a 1D debris flow runoff (DR) model is used for the river channel; and a 2D debris flow flooding or inundation (DF) model is adopted for the lower plains. These models are weakly coupled such that one can modify the overall model to fit diverse problems. In this article, we provide a detailed introduction to the models comprising DFSS, and demonstrate its utility.
Dehydrative synthesis of oxazolidinones from amino alcohols and CO2 was achieved in the presence of alkali metal carbonates such as Cs2CO3 as catalyst. It is noteworthy that 1atm of CO2 is enough for ...the reaction to proceed and no special dehydrating agent is required in this system. A mechanstic study showed that the OH of amino alcohol acts as nucleophile and the OH in the carbamic acid moiety is liberated during the cyclization process.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The haptic sensation of low-frequency vibration plays a vital role in the music listening experience, but it can be enjoyed only in certain facilities and environments. Many haptic devices have been ...proposed to convey music audio-induced vibration for various situations. Such devices require powerful, low-frequency vibration output and transmission over a wide area. Making such devices small and user-friendly is difficult, hindering their popularity. To promote haptic devices for music listening, this paper describes a method for developing a practical device using motors and a thread and evaluates this method's effectiveness. The proposed necklace-type device is small (about 55<inline-formula><tex-math notation="LaTeX">\mathbf \;{\times }</tex-math></inline-formula> 58 <inline-formula><tex-math notation="LaTeX">\mathbf {\times }</tex-math></inline-formula> 15 mm), lightweight (58.5 g), and easy to wear, making it suitable for use during everyday travel. In addition, it can transmit low-frequency (20 Hz) vibrations, whose amplitude exceeds airborne vibration in a nightclub, to a wide area across the chest and neck, with a total power consumption of approximately 2 W. Our proposed method will contribute to the development of practical and high-performance haptic devices for music listening.
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