摂南大学

To investigate the heat conduction behavior during the self-propagating exothermic reaction of Al/Ni multilayer powders, microscale temperature response measurements were conducted on annealed and as-prepared Al/Ni multilayer powders using the thermoreflectance method and the intermetallic compounds were identified through X-ray diffraction analysis. Temperature response measurements from the initial to intermediate reaction stages revealed significant inhomogeneity in thermal propagation at the microscale because of the contrasting thermal conductivities of Al and Ni. In particular, the Ni layer in the Al/Ni lamellar structure likely contributes to thermal resistance. As the temperature increases, Ni diffuses into Al, promoting the formation of Ni-Al intermetallic compounds such as Al3Ni, ultimately leading NiAl formation. Although thermal propagation became spatially uniform, the overall conductivity decreased because of the intrinsically low conductivities of the intermetallic compounds, further limiting thermal propagation. These results indicate that reaction inhibition occurs through different mechanisms at each stage of the exothermic reaction.

Even though the existing literature has elucidated the domestic causes of riots and the links between global food prices and riots, the relationship between riots and various external factors, such as biofuel production, global crude oil prices, speculation, and the US dollar exchange rate, has yet to be fully analyzed. This study aimed to fill this research gap by examining the associations of these external factors on the occurrence of riots in Africa using the Poisson, negative binomial, and zero-inflated negative binomial models. Our key findings are as follows: (1) U.S. ethanol production and international crude oil prices are positively associated with riot frequency, whereas U.S. biodiesel production is not statistically significant. (2) A higher long share relative to open interest increases riot incidence, while a higher short share reduces it. (3) Both international food prices and African domestic food prices exhibit positive and statistically significant associations with riots. (4) Appreciation of the U.S. dollar is negatively correlated with food riots. Overall, the findings suggest that global energy, financial, monetary, and food price dynamics are systematically linked to food riots in Africa.

The Lorentzian type IIB matrix model is a promising candidate for a nonperturbative formulation of superstring theory. In this model, the eigenvalue distribution of the N× N bosonic matrices A_μ (μ= 0 , … , 9) represents an emergent spacetime, which is determined by the dynamics of the model in the large-N limit. Here we perform numerical simulations of the model overcoming the sign problem by the complex Langevin method with the matrix size N up to 128. In order to avoid the singular drift problem due to the Pfaffian, which appears after integrating out the fermionic matrices, we deform the model in a manner inspired by the supersymmetric deformation, which is used to define the “polarized type IIB matrix model” in the Euclidean case. We find that the deformed model exhibits a phase in which (3+1)-dimensional expanding spacetime emerges with both space and time being smooth and real.

The type IIB matrix model has been proposed as a nonperturbative formulation of superstring theory. While numerical simulations of this model are essential for probing nonperturbative effects, such as the emergence of time and an expanding 3–dimensional space, they are hindered by the sign problem. We address this using the Complex Langevin Method (CLM). Furthermore, to suppress spurious numerical artifacts that originate from large Lorentz boosts due to the Lorentz symmetry of the model, we nonperturbatively fix the Lorentz symmetry using the Faddeev–Popov procedure. We then study this model to investigate the impact of supersymmetry on the dynamical generation of (3+1)–dimensional spacetime.

Fruit diseases pose a serious threat to product quality and result in significant economic losses. Severe fruit rot was observed on ripe processing tomatoes in the field in Japan. Round, sunken lesions formed on the fruits, with numerous black conidia in the center; the rot eventually expanded, sometimes over the entire fruit. However, the causal agents of this economically destructive disease had not been clarified. Here, we obtained 40 fungal isolates from lesions on symptomatic ripe tomato fruits. Partial sequences of several housekeeping genes were determined for multilocus sequence typing to identify fungal species. Phylogenetic analysis revealed that six isolates belonged to Colletotrichum species, whereas the remaining 34 isolates were assigned to Alternaria alternata. This result suggests that A. alternata was the ecologically dominant species in the fruit rot lesions. In the pathogenicity test, all Colletotrichum isolates caused sunken lesions with ochre to blackish colonies on ripe fruits but did not produce symptoms on unripe tomatoes. The A. alternata isolates also caused sunken lesions with white to blackish mould only on ripe fruits. Thus, we conclude that both Colletotrichum and A. alternata isolates are the causal agents of this fruit rot of tomato. Sequential inoculation of ripe tomato fruits with Colletotrichum and A. alternata isolates also caused symptoms similar to those in the field, suggesting that a mixed infection can lead to this severe fruit rot.