Idemitsu Kosan (Japan)

Abstract Polyhedral oligomeric silsesquioxane (POSS) has been extensively studied as an essential building block into polymer matrices to improve their thermal and mechanical properties. Although aggregation and dispersion state of POSS segments influence these properties, a deep understanding of POSS aggregation behavior is lacking. In this study, the aggregation behavior of heptaisobutyl-mono-substituted-POSS (7B1R-POSS) was investigated in chloroform (CHCl3), using a simplified model that eliminates various factors within polymer matrices, to understand the mechanism of POSS molecules aggregation. The UV-VIS spectra of 7B1R-POSS solutions with varying concentrations revealed a critical aggregation concentration (CAC), indicating that 7B1R-POSS formed aggregates in CHCl3. Dynamic light scattering (DLS) measurements of 7B1R-POSS solutions above the CAC suggested that the most of aggregation particles were on the order of nanometers, and very few aggregates of a few hundred nanometers were formed. It was found that all 7B1R-POSS exhibited temperature-responsive reversible aggregation behavior, aggregating upon heating, and dispersing upon cooling. This behavior was similar to the entropy-driven behavior observed in polymer micelles, which is known as hydrophobic behavior. In this work, the entropy-driven dominant aggregation behavior in the aggregates of 7B1R-POSS was clarified.

Development of efficient catalysts for ammonia production from atmospheric pressure of dinitrogen at ambient tem-perature has been desired for next-generation scientific techniques to achieve a carbon-neutral society. Herein, we report the synthesis and catalytic activity of a new series of molybdenum trichloride complexes with PCP-type pincer ligands bearing benzoimidazole skeletons connected with aryl groups or a naphthoimidazole skeleton, which have been designed as efficient catalysts for reduction of dinitrogen into ammonia, based on our previous computational screening. The large π-conjugated structure of the pincer ligands effectively increased the electron-accepting ability of the molybdenum complexes without compromising their proton-accepting abil-ity, resulting in the promotion of the rate-determining step (i.e., the proton-coupled electron transfer (PCET) to the nitride complexes as a key reaction intermediate) and catalytic activity toward ammonia formation from dinitrogen under ambient reaction conditions. As a result of both theoretical and experimental investigations, the so far highest turnover frequencies for ammonia formation (TOF(NH3), up to 900 equiv./Mo•min−1) and maximum turnover number (TON(NH3), up to 84,000 equiv./Mo) were successfully achieved by using molybdenum complexes with a 3,5-bis(trifluoromethyl)phenyl (ArF) group on the benzoimidazole skeleton because of the synergistic effect of the ArF group, i.e., the extension of the π-conjugation in the ligand and the electron-withdrawing ability.

All-solid-state lithium-ion batteries face challenges in terms of increasing their capacity for high-speed charging and discharging, which will require optimization of the electrode structure. This structure comprises a solid electrolyte (SE) and active material (AM) and the AM particle size is one of the most important factors affecting the structure. The present study examined the effects of AM particle size on electrode structure and performance through discharge experiments, X-ray computed tomography (CT), and pseudo-two-dimensional (P2D) simulations. The SE tortuosity and AM specific contact area diameter (DSCA) used in the P2D simulations were obtained from X-ray CT data and the results of these simulations were verified through a comparison with experimental data. The latter indicated that smaller AM particle sizes provided increased battery performance. The P2D simulations based on DSCA values were found to be highly accurate and showed the same correlation between particle size and performance. These simulations also demonstrated that changes in performance originate from differences in the overpotential associated with lithium diffusion in the AM particles. Specifically, smaller AM particles having lower DSCA values reduce the overpotential associated with lithium diffusion to give improved performance.

CIGS solar cells are promising light-receiving elements for optical wireless power transmission (OWPT) systems because they are inexpensive and receive light in the long wavelength range that is relatively safe for human eyes. A photoelectric conversion efficiency η_pv of the CIGS solar cell (10 mm x 10 mm) on a metal substrate was examined under a 1064 nm laser irradiation. We obtained η_pv values of 31.2% and 26.8% under a 1064 nm laser irradiation of 0.9 W/cm² (84 mW) and 2.6 W/cm² (244 mW), respectively. In anticipation of social implementation, we also demonstrated the influence of the size of the laser irradiation area on the conversion efficiency of CIGS solar cells. The photoelectric conversion efficiency did not change when the irradiated area was varied. These results could expand the possibility of applying CIGS solar cells to OWPT systems.

This study involved a mine in Akita Prefecture, Japan, which was closed in the 1970s and from which acid mine drainage (AMD) flows into a nearby river, after pH adjustment. During rainfall events, surface water was flowing in through the adit mouths and sinkholes of excavated areas. Therefore, countermeasure works to reclaim these were carried out by the project company, between 2017 and 2022. In methodology development, this study aims to evaluate the effectiveness of the countermeasures. AMD flow rate increases with rainfall, and water quality of AMD is acidic (pH 3.0–3.8) with higher concentrations of SO42–, soluble Fe, Cu, and Zn than those of river water. The AMD flow rate, normalized using precipitation, decreased over time, with a 55% decrease in 2022 relative to 2016. With progress in countermeasures, pH of the AMD increases, with a range of change of about 0.2, and concentrations of heavy metals in the AMD decreased. Local inhabitants use river water downstream of the mine, at a point-of-use, for agricultural purposes. Since precipitation phenomena such as heavy metals are not recognized in SO42–, an index indicating the degree of impact of AMD on the water quality of the point-of-use was calculated using SO42– as a contribution ratio; CR. The CR of the AMD to water quality at the point-of-use is in the range of 1.3%–11.8% and decreased over time.

Abstract A cracking damage was found in 347SS flange neck operated at about 520 deg. C after long term operation. In previous report presented in PVP2019-9304, it was well explained by creep damage from FEM analysis using isochronous curve based on API 579/ASME FFS-1 MPC Omega method. Following our previous paper, specimens were obtained from the replaced flange operated for 4 years. Using those specimens, destructive testing and remaining life assessment were performed to validate the analysis. As a result, specimens from the flange neck showed relatively short rupture life, compared to those from other locations. MPC Omega method along with adjustment factors derived from testing resulted in remaining life of 3.1 to 6.8 × 105 hrs. at average operating condition. In consideration with temperature variation during operation, remaining life is estimated to be 2.6 × 10-5 hrs., indicating 10 % life consumption at the time of taking sample. Life consumption estimated by FEM analysis is rather conservative but is comparable within factor of 2 when average strength is applied for the evaluation. Since the estimated stress conditions and test conditions are close to 0.2% proof stress of the material at this temperature range, significant primary creep strain was observed in the tests, that can cause some conservativeness in remaining life by the FEM analysis. While above, Larson Miller Parameter method also adjusted with rupture test data agrees with MPC Omega method on the assumption of uniaxial tension. However, it gives less-conservative life under the multiaxial stress conditions. Effect of multiaxial stress on creep life is more significantly observed in MPC Omega method, especially when stress ratio is higher. In this part I of two papers, the detail of creep test will be presented and discussed. In part II, current creep temperature limit shown in API579-1/ASME FFS-1 Part 4 Table 4.1 will be discussed and suggest an upgrade of creep temperature criteria based on the multi-axial creep model we learned through studies.

Transparent polypropylene(PP)decorative sheets make an ideal molding material in terms of recyclability. However, surface defects, particularly wrinkling, occur in PP sheets during the inmold injection molding process. In this study, we analyzed the occurrence of wrinkles in decorative sheets by visualization experiments of the molding process as well as clarified the relationship between wrinkle depth and molding conditions, and measured the sheet deformation amount and shear force between the sheet and cavity surface. We found that the wrinkle generation phenomenon of PP sheets was caused by sheet deformation along the flow direction with sheet slippage on the cavity surface after passage of the flow front. The sheet deformation decreased as if according to a power-law distribution in line with increasing screw injection speed and it occurred over the front contact area for only a very short time immediately after the flow front passed. Based on these results, we proposed a sheet deformation model, where at the moment the flow front passed, the perpendicular force FZ and derived frictional force FS to the cavity surface did not rise enough to fix the sheet onto the cavity surface. Therefore, the sheet slipped on the mold surface and deformed with thermal expansion and deformation stress caused by flowing melts. After the FZ derived FS rose enough to fix the sheet onto the cavity surface, the sheet deformation stopped. These deformations in micro regions were integrated and the sheet wrinkle which had occurred was thought to be due to the redundant length of the sheet.