Effect of UHPFRC Overlay on Fatigue Cracks Propagating from U-rib Welds of Orthotropic Steel Decks

Masafumi Hattori,Kazuo Tateishi,Takeshi Hanji,Masaru Shimizu 한국강구조학회 2022 International Journal of Steel Structures Vol.22 No.6

Over the last decade, fatigue cracks have been observed at welded joints between U-ribs and deck plates in many orthotropic steel deck bridges in Japan. This paper focuses on fatigue cracks that initiate from a weld root of rib-to-deck welded joints and propagate to a deck plate. This study examines the eff ect of a countermeasure that uses overlaying Ultra-High Performance Fiber Reinforced cement-based Composites (UHPFRCs) on steel decks with cracks from U-rib welds, and confi rms the fatigue durability of this method. Specifi cally, the retardation of crack propagation and the fatigue durability of the UHPFRC itself as well as the interface between the UHPFRC and the deck plate were confi rmed by a wheel running test and fi nite element analysis. Based on the results, it was clarifi ed that this countermeasure has a positive eff ect on retarding further crack propagation compared with the method of overlaying steel fi ber reinforced concrete, which is generally adopted. In addition, it was revealed that the studied countermeasure has suffi cient fatigue durability.

Pressure-induced Metal-insulator Transition of the Mott Insulator Ba2IrO4

Daisuke Orii,Masafumi Sakata,Atsushi Miyake,Katsuya Shimizu,Hirotaka Okabe,Masaaki Isobe,Eiji Takayama-Muromachi,Jun Akimitsu 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.63 No.3

The electrical resistivity of single crystals of the spin-orbit Mott insulator Ba2IrO4 has beenmeasured at pressures up to 30 GPa and at temperatures from 100 mK to 300 K. Ba2IrO4 showsa metal-insulator transition at around Pc = 24 GPa, though it does not show superconductivitydown to 100 mK. The low-temperature resistivity in the metallic state does not obey a conventionalFermi-liquid description. This suggests that carriers are incoherently scattered by antiferromagneticquantum spin fluctuations. The critical exponent for the metal-insulator transition is about 1.6,indicating that Ba2IrO4 is located near the boundary between a Mott and an Anderson insulator. This means that even in a single crystal, the effect of crystallographic disorder should not be ignored.

Fabrication and Characterization of Perovskite (Bi,Sm)(Ni,Ti)O3 Thin Films by Rf Magnetron Sputtering

Hideto Tada,Masafumi Kobune,Koji Fukushima,Hisashi Oshima,Daisuke Horit,Akihiro Tamura,Yusuke Daiko,Atsushi Mineshige,Tetsuo Yazawa,Hironori Fujisawa,Masaru Shimizu,Hideshi Yamaguchi,Koichiro Honda 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.55 No.2

The structural characteristics, the mechanism of crystal growth, and the ferroelectric properties of partially Sm-substituted perovskite bismuth-samarium-nickel-titanate [(Bi1−xSmx)(Ni0.5Ti0.5)- O3; BSNT, x = 0− 0.9] thin films deposited on Pt(100)/MgO(100) substrates by rf sputtering have been investigated using X-ray diffraction, transmission electron microscope, and polarization - electric field hysteresis loop measurements. The fabricated BSNT samples with x≥0.6 were confirmed to have a single-phase perovskite structure. Of the four samples (x = 0.6 0.7, 0.8, and 0.9) with a single-phase perovskite structure, the c-axis-oriented epitaxial BSNT film with x = 0.9 exhibited the best hysteresis loop, with a remanent polarization of 2 μC/cm2 and a coercive field of 100 kV/cm. The structural characteristics, the mechanism of crystal growth, and the ferroelectric properties of partially Sm-substituted perovskite bismuth-samarium-nickel-titanate [(Bi1−xSmx)(Ni0.5Ti0.5)- O3; BSNT, x = 0− 0.9] thin films deposited on Pt(100)/MgO(100) substrates by rf sputtering have been investigated using X-ray diffraction, transmission electron microscope, and polarization - electric field hysteresis loop measurements. The fabricated BSNT samples with x≥0.6 were confirmed to have a single-phase perovskite structure. Of the four samples (x = 0.6 0.7, 0.8, and 0.9) with a single-phase perovskite structure, the c-axis-oriented epitaxial BSNT film with x = 0.9 exhibited the best hysteresis loop, with a remanent polarization of 2 μC/cm2 and a coercive field of 100 kV/cm.

Structural Characteristics of Epitaxially a- and b-axis-oriented (Bi_(3.25)Nd_(0.75))Ti_3O_(12) Films Fabricated on Conductive Nb:TiO_2 Substrates by High-temperature Sputtering

Akihiro Tamura,Masafumi Kobune,Kazuki Imagawa,Hisashi Oshima,Yusuke Daiko,Atsushi Mineshige,Tetsuo Yazawa,Hiroshi Nishioka,Hironori Fujisawa,Masaru Shimizu,Hideshi Yamaguchi,Koichiro Honda 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.31

3.0-mm-thick a- and b-axis-oriented (Bi_(3.25)Nd_(0.75))Ti_3O_(12) (BNT-0.75) films were fabricated on conductive Nb:TiO_2(101) (Nb = 0, 0.048, 0.46, 0.79 mass%) single crystal substrates by high-temperature sputtering. A BNT films grown on undoped TiO_2 substrates have no orientation, whereas BNT films deposited on Nb:TiO_2 substrates with 0.46-0.79 mass% Nb show strong (h00/0k0) diffractions and grow with a heteroepitaxial relationship to the underlying Nb:TiO_2 substrates. The BNT-0.75 film deposited on Nb:TiO_2(101) substrate with 0.79 mass% Nb was indicated the peculiar shape of approximately 100-150-nm-thick nanoplates. We speculate that the driving force for producing a plate-like structure for BNT films is attributed to the large anisotropy of linear expansion coefficients for Bi_4Ti_3O12, and the comparatively small lattice matching between Nb:TiO_2 substrate and BNT film.

Fabrication of Inorganic-organic Composites Containing Ferroelectric Nanoplates and Evaluation of their Piezoelectric Response Characteristics

Ryo Kishimoto,Masafumi Kobune,Hiroshi Nishioka,Takeyuki Kikuchi,Hajime Kishi,Hironori Fujisawa,Seiji Nakashima,Masaru Shimizu,Satoshi Kimura 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.62 No.7

<EM>a-</EM> and <I>b</I>-axis-oriented Bi<SUB>3.25</SUB>Nd<SUB>0.75</SUB>Ti<SUB>3</SUB>O<SUB>12</SUB> (BNT) nanoplates, 3.0 mm thick, were fabricated on conductive Nb:TiO<SUB>2</SUB>(101) substrates with 0.79 mass% Nb at 650C by high-temperature sputtering. Successively, the fabrication of inorganic-organic composites was carried out by introducing an epoxy resin to the spaces between BNT nanoplates. The fourier transform infrared spectroscopy (FT-IR) and energy dispersive X-ray (EDX) elemental mapping results confirmed that the fabricated composite was an inorganic-organic hybridized material which introduced the cured epoxy resin into the spaces between BNT nanoplates. Based on polarization reversal measurements of the fabricated BNT-epoxy resin composites by piezoresponse force microscopy (PFM), it is shown that the composites have potential as ferroelectric microelement materials.

Occurrence of Root Rot and Vascular Wilt Diseases in Roselle(Hibiscus sabdariffa L.) in Upper Egypt

( Naglaa Hassan ),( Masafumi Shimizu ),( Mitsuro Hyakumachi ) 한국균학회 2014 Mycobiology Vol.42 No.1

Roselle(Hibiscus sabdariffa L.) family Malvaceae is an important crop used in food, cosmetics and pharmaceutics industries. Roselle is cultivated mainly in Upper Egypt(Qena and Aswan governorates) producing 94% of total production. Root rot disease of roselle is one of the most important diseases that attack both seedlings and adult plants causing serious losses incrop productivity and quality. The main objective of the present study is to identify and characterize pathogens associated withroot rot and wilt symptoms of roselle in Qena, Upper Egypt and evaluate their pathogenicity under greenhouse and field condition. Fusarium oxysporum, Macrophomina phaseolina, Fusarium solani, Fusarium equiseti and Fusarium semitectum were isolated from the natural root rot diseases in roselle. All isolated fungi were morphologically characterized and varied in their pathogenic potentialities. They could attack roselle plants causing damping-off and root rot/wilt diseases in different pathogenicitytests. The highest pathogenicity was caused by F. oxysporum and M. phaseolina followed by F. solani. The least pathogenic fungi were F. equiseti followed by F. semitectum. It obviously noted that Baladi roselle cultivar was more susceptible to infection with alltested fungi than Sobhia 17 under greenhouse and field conditions. This is the first report of fungal pathogens causing root rot and vascular wilt in roselle in Upper Egypt

Induction of Systemic Resistance against Cucumber mosaic virus in Arabidopsis thaliana by Trichoderma asperellum SKT-1

Elsharkawy, Mohsen Mohamed,Shimizu, Masafumi,Takahashi, Hideki,Ozaki, Kouichi,Hyakumachi, Mitsuro The Korean Society of Plant Pathology 2013 Plant Pathology Journal Vol.29 No.2

Trichoderma asperellum SKT-1 is a microbial pesticide that is very effective against various diseases. Our study was undertaken to evaluate T. asperellum SKT-1 for induction of resistance against yellow strain of Cucumber mosaic virus (CMV-Y) in Arabidopsis plants. Disease severity was rated at 2 weeks post inoculation (WPI). CMV titre in Arabidopsis leaves was determined by indirect enzyme-linked immunosorbent assay (ELISA) at 2 WPI. Our results demonstrated that among all Arabidopsis plants treated with barley grain inoculum (BGI) of SKT-1 NahG and npr1 plants showed no significant reduction in disease severity and CMV titre as compared with control plants. In contrast, disease severity and CMV titre were significantly reduced in all Arabidopsis plants treated with culture filtrate (CF) of SKT-1 as compared with control plants. RT-PCR results showed increased expression levels of SA-inducible genes, but not JA/ET-inducible genes, in leaves of BGI treated plants. Moreover, expression levels of SA- and JA/ET-inducible genes were increased in leaves of CF treated plants. In conclusion, BGI treatment induced systemic resistance against CMV through SA signaling cascade in Arabidopsis plants. While, treatment with CF of SKT-1 mediated the expression of a majority of the various pathogen related genes, which led to the increased defense mechanism against CMV infection.

Induction of Systemic Resistance against Cucumber mosaic virus in Arabidopsis thaliana by Trichoderma asperellum SKT-1

Mohsen Mohamed Elsharkawy,Mitsuro Hyakumachi,Masafumi Shimizu,Kouichi Ozaki,Hideki Takahashi 한국식물병리학회 2013 Plant Pathology Journal Vol.29 No.2

Trichoderma asperellum SKT-1 is a microbial pesticide that is very effective against various diseases. Our study was undertaken to evaluate T. asperellum SKT-1 for induction of resistance against yellow strain of Cucumber mosaic virus (CMV-Y) in Arabidopsis plants. Disease severity was rated at 2 weeks post inoculation (WPI). CMV titre in Arabidopsis leaves was determined by indirect enzyme-linked immunosorbent assay (ELISA) at 2 WPI. Our results demonstrated that among all Arabidopsis plants treated with barley grain inoculum (BGI)of SKT-1 NahG and npr1 plants showed no significant reduction in disease severity and CMV titre as compared with control plants. In contrast, disease severity and CMV titre were significantly reduced in all Arabidopsis plants treated with culture filtrate (CF) of SKT-1as compared with control plants. RT-PCR results showed increased expression levels of SA-inducible genes,but not JA/ET-inducible genes, in leaves of BGI treated plants. Moreover, expression levels of SA- and JA/ETinducible genes were increased in leaves of CF treated plants. In conclusion, BGI treatment induced systemic resistance against CMV through SA signaling cascade in Arabidopsis plants. While, treatment with CF of SKT-1 mediated the expression of a majority of the various pathogen related genes, which led to the increased defense mechanism against CMV infection.

Control of Root Rot and Wilt Diseases of Roselle under Field Conditions

( Naglaa Hassan ),( Mohsen Mohamed Elsharkawy ),( Masafumi Shimizu ),( Mitsuro Hyakumachi ) 한국균학회 2014 Mycobiology Vol.42 No.4

Roselle (Hibiscus sabdariffa L.) is one of the most important medicinal crops in many parts of the world. In this study, the effects of microelements, antioxidants, and bioagents on Fusarium oxysporum, F. solani, and Macrophomina phaseolina, the causal pathogens of root rot and wilt diseases in roselle, were examined under field conditions. Preliminary studies were carried out in vitro in order to select the most effective members to be used in field control trials. Our results showed that microelements (copper and manganese), antioxidants (salicylic acid, ascorbic acid, and EDTA), a fungicide (Dithane M45) and biological control agents (Trichoderma harzianum and Bacillus subtilis) were significantly reduced the linear growth of the causal pathogens. Additionally, application of the previous microelements, antioxidants, a fungicide and biological control agents significantly reduced disease incidence of root rot and wilt diseases under field conditions. Copper, salicylic acid, and T. harzianum showed the best results in this respect. In conclusion, microelements, antioxidants, and biocontrol agents could be used as alternative strategies to fungicides for controlling root rot and wilt diseases in roselle.

Effect of Theaflavin on Oral Bacteria in Japanese Subjects: A Randomized, Placebo-Controlled, Double-Blind Study

Yasufumi Katanasaka,Naoki Yoshida,Hirotaka Naitou,Ryuya Naruta,Yusuke Miyazaki,Yoichi Sunagawa,Masafumi Funamoto,Kana Shimizu,Satoshi Shimizu,Numila Sari,Hajime Yamakage,Noriko Satoh-Asahara,Koji Hase 한국식품영양과학회 2021 Journal of medicinal food Vol.24 No.11

Black tea is a popular beverage worldwide. Theaflavins (TFs), which are active functional components of black tea, are potentially valuable for preventing and/or treating the progression of periodontal diseases. Our previous pilot study showed that TF intake decreases the number of Porphyromonas gingivalis (P. gingivalis) bacteria in the saliva. In this study, we aimed to determine whether TF intake improves periodontal disease attributed to oral bacteria in a randomized, placebo-controlled, and double-blind study. A total of 56 healthy subjects without periodontal diseases were enrolled and assigned to the placebo and TF groups (n = 28). TF intake for 6 weeks did not significantly alter the clinical evaluation of subjects. There was no significant adverse effect among the subjects. The number of P. gingivalis and Fusobacterium nucleatum (F. nucleatum) bacteria, which was the primary endpoint in this study, was not impacted by TF intake. The change ratio of Prevotella intermedia was significantly decreased by TF intake (P = .043) when compared with the placebo group. Collectively, our findings suggest that TFs have beneficial effects on oral bacteria for the prevention of periodontal disease. The study protocol was registered in the University Hospital Medical Information Network (UMIN000020049).