Reconnaissance report on geotechnical damage caused by a localized torrential downpour with emergency warning level in Kyushu,Japan

Kumamoto and Kogoshima prefectures are located in the southern Kyushu district of western Japan. In July 2020, a warm, humid air front triggered the delayed rains of the rainy season, resulting in torrential rains in many parts of Japan, especially in Kyushu. In particular, heavy downpours occurred in the southern Kyushu district on July 4th, causing severe damage to much of the infrastructure. Details could not be analyzed as usual because some branch office of local government were also damaged by floods. The spatial distribution of precipitation in the Kuma River basin, in the southern part of Kumamoto, was characterized by the uniformity of 400–500 mm on July 3rd and 4th. Finally, emergency warnings of torrential rain were issued for the southern Kumamoto and the northern Kagoshima Prefectures by Japan Meteorological Agency (JMA) at 4:50 a.m., July 4th, 2020. Then, the active rain front gradually shifted towards northern Kyushu. Again, torrential rain fell on northern Kyushu in the afternoon due to a stagnant rainy season front, and the JMA issued an emergency warning for a localized torrential downpour for parts of Fukuoka, Saga and Nagasaki prefectures at 4:30 pm. Gradually, the damage status involving geodisasters such as several types of slope failures, road subsidence, damage of the river levee was reported by local governments in each area where there had been emergency warnings.Based on the brief report of the pre-investigation team from the Kyushu branch of the Japan Geotechnical Society (JGS) in the first week after the disaster on July 4th, the geo-research teams investigated the following: 1) landslides; 2) damaged roads; 3) damaged river levees, and 4) any geotechnical infrastructures which were partially damaged and may be even more severely damaged by the next torrential rain. This reconnaissance report introduces the geological features in Kyushu, the analysis of precipitation distribution and geotechnical damages on the slope failures, road failures and river embankments based on reports obtained from July 4th to August 31st, 2020.     

Synthesis of silica hybrid nanoparticles modified with photofunctional polymers and construction of colloidal crystals

Photofunctional polymer as silane coupling agent (PFD) was prepared by free radical copolymerization of 4‐vinylbenzyl N,N‐diethyldithiocarbamate (VBDC) and methyl methacrylate (MMA) in the presence of (3‐mercaptopropyl)trimethoxysilane (MPMS) as chain transfer agent. Next, silane (SiO₂; the average diameter D_n = 192 nm) nanoparticles was surface‐modified with PFD and 3‐(trimethoxysilyl)propyl methacrylate (γ‐MPS) by covalent bond formed between silanol groups and silane coupling agents. The PFD and γ‐MPS functionalizations changed the silica surface into hydrophobic nature and provided grafting initiation sites and methacrylate terminal groups respectively. We performed the construction of hybrid nanocomposites by using these modified SiO₂ nanoparticles. It was found from electron microscopy observations that SiO₂ particles were packed into repeating cubic arrangements in a poly(methyl methacrylate) (PMMA) matrix such as colloidal crystals. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Thermal and dynamic mechanical properties of organic–inorganic hybrid composites of itaconate‐containing poly(butylene succinate) and methacrylate‐substituted polysilsesquioxane

Itaconate‐unit‐containing poly(butylene succinate) (PBSI) was synthesized by the reaction of 1,4‐butanediol, succinic acid, and itaconic acid in a molar ratio of 2.0 : 1.0 : 1.0, and the obtained PBSI was reacted with methacryl‐group‐substituted polysilsesquioxane (ME‐PSQ) in the presence of benzoyl peroxide (BPO) at 130°C to produce PBSI/ME‐PSQ hybrid composites. The thermal and dynamic mechanical properties of the PBSI/ME‐PSQ hybrid composites were investigated in comparison with those of PBSI cured at 130°C in the presence of BPO. As a result, the hybrid composites showed a much higher thermal degradation temperature and storage modulus in the rubbery state than the cured PBSI (C‐PBSI). The thermal degradation temperature and storage modulus of the hybrid composites increased with increasing ME‐PSQ content. The glass‐transition temperature, measured by dynamic mechanical analysis of the hybrid composites, somewhat increased with increasing ME‐PSQ content. However, the glass‐transition temperatures of all the hybrid composites were lower than that of C‐PBSI. Although the IR absorption peak related to C?C groups was not detected for C‐PBSI, some olefinic absorption peaks remained for all the hybrid composites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Relaxation behavior of polymers probed by positron annihilation lifetime spectroscopy

Relaxation behaviors of polyethylene, polypropylene, and polycarbonate have been studied by positron annihilation lifetime spectroscopy (PALS). In PALS positron sources made of radioisotopes are used to inject positrons into polymer as a micro probe. The injected positron probes can induce radiation effect, which plays an important role in detecting the polymer relaxation behavior through electrons trapped in shallow potentials at low temperature. Monitoring the intensity (I₃) of ortho-positronium (o-Ps), transitions of γ and δ relaxation can be measured by PALS as a secondary effect. In this experiment, the change of I₃ below Tg is connected with the number of the trapped electrons, which can be excited from the shallow potential by the thermal motion of polymer structures and visible light irradiation. In the PALS measurements of non-irradiated PP samples, relaxation of methyl groups was observed as low as 50 K, which can be assigned as the δ relaxation. Relaxations of β and γ were also observed for the non-irradiated PP samples between 100–370 K. However for the 3 MGy γ-ray irradiated PP samples, only β relaxation was observed because the large radiation dose caused a large number of scissions of –CH₃ groups from main chains and the characteristics changed. For the irradiated samples, radiation hardening was observed. Electronic Publication     

Influence of anions on the formation of β-FeOOH rusts

The artificial β-FeOOH rusts were synthesized by oxidation of FeCl₂ solutions and hydrolysis of FeCl₃ solutions. Various Na salts such as sulfate, biphosphate, nitrate, and silicate were added to the starting solutions at different anion/Fe molar ratios of 0-0.05. The XRD patterns of the products showed only the diffraction peaks of β-FeOOH. The crystallinity of the products was noticeably reduced by adding and but slightly influenced by adding . The addition of markedly crystallized the products by the hydrolysis of FeCl₃. The N₂ adsorption revealed that the products with were porous particles assembled by β-FeOOH subcrystals. and strongly coordinating to Fe(III) markedly lowered the crystallinity of the products and remained in the formed particles.     

Structure Modification of Alloy Solidified With Electromagnetic Field

A S45C carbon steel has been solidified under different electromagnetic conditions to investigate the effect of the electromagnetic force imposition and its imposing period on the solidified structure in this study.For excitation of the electromagnetic force,a static magnetic field and a direct electric current were simultaneously imposed on a sample under a certain period of the solidification.After the solidification,the microstructures were observed and compared each other.As the results,microstructure of the S45C steel under the simultaneous imposition of a static magnetic field of 1T and a direct electric current of 20A in the latter stage of its solidification was dendritic while it was globular if the electromagnetic force was imposed during the whole solidification period.     

Positron annihilation spectroscopic evidence to demonstrate the flux-enhancement mechanism in morphology-controlled thin-film-composite (TFC) membrane

In this study, positron annihilation lifetime spectroscopy (PALS) is applied to explain the flux-enhancement mechanism in thin-film-composite (TFC) membranes prepared by using dimethyl sulfoxide (DMSO) as an additive in the interfacial polymerization. The TFC membranes show a large increase in water flux, up to 5-fold, compared to nonadditive membrane. Atomic force microscopy (AFM) shows that surface roughness and surface area increase when DMSO in the aqueous phase solution phase works to increase miscibility of the aqueous and the organic phase by reducing the solubility difference of two immiscible solutions. X-ray photoelectron spectroscopy (XPS) reveals the variation of the chemical compositions to the extent that there is a considerable increase in the cross-linked amide linkages of the flux-enhanced TFC membranes. The effects of these structural changes on the molecular-size free volume properties are evaluated by PALS studies. The PALS results are the first to experimentally show that the thin films of cross-linked aromatic polyamide RO membranes are composed of two types of pores having radii of about 2.1-2.4 A from tau3, network pore, and 3.5-4.5 A from tau4, aggregate pore. The increase in the size and number of network pores by means of DMSO addition during interfacial polymerization enhances the water flux notably. The size of aggregate pores also increases and may contribute to enhance water flux, although their number inevitably decreases as the number of network pores becomes increased. Details on the correlations between RO performances and o-Ps lifetime parameters are clearly described based on the pore-flow model of reverse osmosis developed by Sourirajan et al.     

N-acetyltransferase activity in the urine in Japanese subjects: comparison in healthy persons and bladder cancer patients

The activity of urinary N-acetylamino-transferase was determined by high-performance liquid chromatographic assay of acetylisoniazid and isoniazid after administration of isoniazid to healthy Japanese male and bladder cancer patients in Japan. The healthy subjects were 47 college students and 44 company employees ranging from 18 to 64 years old (mean +/- SC = 34.5 +/- 13.7). The bladder cancer group consisted of 58 male and 13 female patients, ranging from 28 to 82 years old (mean +/- SD = 60.8 +/- 11.6), who were being treated at several hospitals. The slow phenotype, defined as an acetylation ratio (acetylisoniazid/isoniazid) of less than 2.0, was observed in 13 (14.3%) of the 91 healthy subjects, and in 20 (28.2%) of the 71 bladder cancer patients; the difference between the two groups is significant (p < 0.05). A histogram of the acetylation ratio values showed an overall leftward shift of the patient group, indicating low values of acetylation ratio in this group as a whole (p < 0.01).     

Preparation of glycidyl celluloses from completely allylated methylcellulose and tri-O-allylcellulose

Glycidyl celluloses were prepared from completely allylated methylcellulose and tri-O-allylcellulose with m-chloroperbenzoic acid in homogeneous chloroform solutions. The degrees of substitution (DS) by epoxy groups were 0.60 and 1.33 for the products prepared from allylated methylcellulose and tri-O-allylcellulose, respectively. They were soluble in not only many organic solvents, but also methanol-water mixtures [more than 70% (v/v)]. These products were characterized by infrared spectroscopy (IR), ¹³C-NMR spectroscopy, and gel permeation chromatography (GPC).