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Three-Dimensional Visualization of Shock Cell Structure and Screech Tone Emission in Underexpanded Circular Jet

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Journal of Flow Control, Measurement & Visualization 2022年第1期10卷 1-11页

作者： Keita Ozawa takayuki Yamagata Nobuyuki Fujisawa Graduate School of Science and Technology Niigata University Niigata Japan Department of Mechanical Engineering Niigata University Niigata Japan Department of Mechanical Engineering Shinshu University Nagano Japan

The three-dimensional visualization of flow and screech-tone emission from an underexpanded circular jet is first investigated experimentally using high-speed cross-schlieren imaging and microphone measurements in the cross-sectional planes along the jet axis. This experimental technique allows the visualization of the shock-cell structure, directivity of sound intensity, and frequency spectrum in the cross-sectional planes of the screeching jet. The high-speed cross-schlieren observation of the screeching jet shows the occurrence of an asymmetrical shock-cell structure that is generated by the flapping mode in the screeching jet. This contributes to the generation of a screech tone propagating upstream along the jet axis and non-uniform sound intensities around the jet in circumferential direction. These observations by high-speed cross-schlieren imaging were validated by the microphone measurements.

关键词： Screech Tone Aeroacoustics Directivity Frequency Spectrum Underexpanded Circular Jet Schlieren Imaging

Influence of Stand-Alone Vertical Gas Vents on Aeration and Denitrification of Organic Municipal Waste Assessed by Two-Dimensional (2D) Lysimeters

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Journal of Geoscience and Environment Protection 2023年第12期11卷 209-228页

作者： Tadis Dillon takayuki Shimaoka Teppei Komiya Department of Urban and Environmental Engineering Faculty of Engineering Kyushu University Fukuoka Japan

Landfilled organic waste, in the presence of oxygen, can undergo aerobic decomposition facilitated by heterotrophic microorganisms. Aerobic degradation of solid waste can quickly consume available oxygen thus curtailing further degradation. The aim of this study was the investigation of a low-cost method of replenishing oxygen consumed in landfilled waste. Three 2D lysimeters were established to investigate the effectiveness of stand-alone, vertical ventilation pipes inserted into waste masses. Two different configurations of ventilation were tested with the third lysimeter acting as an unventilated control. Lysimeters were left uninsulated and observed over the course of 6 months with regular collection of gas and leachate samples. Lysimeters were then simulated for Oxygen (O2) and Nitrous oxide (N2O) to analyze the denitrification contributions of each. The experiment revealed that a single ventilation pipe can increase the mean oxygen level of a 1.7 m × 1.0 m area by up to 13.5%. It also identified that while increasing the density of ventilation pipes led to increased O2 levels, this increase was not significant at the 0.05 probability level. A single vent averaged 13.67% O2 while inclusion of an additional vent in the same area only increased the average to 14.59%, a 6.7% increase. Simulation helped to verify that lower ventilation pipe placement density may be more efficient as in addition to the effect on oxygenation, denitrification efficiency may increase. Simulations of N2O production estimated between 8% - 20% more N2O being generated with lower venting density configurations.

关键词： Organic Waste Waste Stabilization Passive Aeration 2D Lysimeter COMSOL Multiphysics In-Situ Aeration

Role of animal models in glaucoma research

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Neural Regeneration Research 2020年第7期15卷 1257-1258页

作者： Atsuko Kimura Takahiko Noro takayuki Harada Visual Research Project Tokyo Metropolitan Institute of Medical Science

Glaucoma is a neurodegenerative disease of the eye,and it presents with visual field defects accompanied by progressive degeneration of the optic nerve and retinal ganglion cells(RGCs).It is one of the major causes of blindness worldwide and affects 1 in 20 people over the age of *** is caused by multiple factors,but it is usually associated with elevated intraocular pressure(IOP).Extensive studies have been carried out to discover therapeutic targets and to develop new drugs to treat ocular hypertension using experimental models of rodents(rats and mice)and non-human primates(e.g.,cynomologus,rhesus,or marmoset monkeys).

关键词： elevated degeneration drugs

Relationship between Serum L-Carnitine Levels and Sperm Parameters in Boars

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Open Journal of Animal Sciences 2022年第3期12卷 360-365页

作者： Seizi Sukemori takayuki Watanabe Satoshi Odo Department of Production Environment and Economy Shizuoka Professional University of Agriculture Shizuoka Japan Lonza Co. Ltd. Tokyo Japan

This study evaluated the relationship between serum L-carnitine level and sperm parameters in young boars. Serum L-carnitine and semen characteristics were determined for 61 young Duroc boars between the ages of 590 and 630 days. Multiple linear regression analysis was performed to predict total and progressive motility and the total number of spermatozoa based on serum total L-carnitine and free L-carnitine levels. Total number of spermatozoa was not associated with basal serum L-carnitine levels. A regression equation was found in which both total L-carnitine levels and free L-carnitine levels were significant predictors of total and progressive motility (P 0.05). These results suggest that serum L-carnitine level is an important selection parameter for stock boars.

关键词： Serum L-Carnitine Sperm Total Motility Sperm Progressive Motility Boar

Solutions of the 1D Coupled Nonlinear Schrodinger Equations by the CIP-BS Method

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Communications in Computational Physics 2006年第2期1卷 261-275页

作者： takayuki Utsumi takayuki Aoki James Koga Mitsuru Yamagiwa Department of Electronics and Computer Science Tokyo University of ScienceYamaguchi1-1 Daigaku-doriSanyou-OnodaYamaguchi 756-0884Japan Global Scientific Information and Computing Center Tokyo Institute of TechnologyO-okayamaMeguro-kuTokyo 152-8552Japan Japan Atomic Energy Agency 8-1 Umemidai Kizu-choSouraku-gunKyoto 619-0215Japan

In this paper,we present solutions for the one-dimensional coupled nonlinear Schrödinger(CNLS)equations by the Constrained Interpolation Profile-Basis Set(CIP-BS)*** method uses a simple polynomial basis set,by which physical quantities are approximated with their values and derivatives associated with grid *** operations on functions are carried out in the framework of differential ***,by introducing scalar products and requiring the residue to be orthogonal to the basis,the linear and nonlinear partial differential equations are reduced to ordinary differential equations for values and spatial *** method gives stable,less diffusive,and accurate results for the CNLS equations.

关键词： The CIP-BS method basis set differential algebra the Galerkin method the coupled nonlinear Schrödinger equation

Feasibility of Natural Zeolite for Heavy Metal Stabilization in Municipal Solid Waste Incineration Fly Ash: A Novel Approach

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Journal of Geoscience and Environment Protection 2022年第7期10卷 70-86页

作者： Mitali Nag Amirhomayoun Saffarzadeh takayuki Shimaoka Department of Urban and Environmental Engineering Faculty of Engineering Kyushu University Fukuoka Japan

The current study investigated the sorption process of heavy metals, especially lead (Pb2+) and Zinc (Zn2+), in Municipal Solid Waste Incineration (MSWI) fly ash applying natural zeolite, namely mordenite, as an inexpensive adsorbent to assess its feasibility for the treatment of fly ash. Batch experiments were performed to investigate the effects of the influential parameters, such as metals initial ion concentration, dosage of adsorbent, liquid to solid (L/S) ratio, and equilibrium concentration of metal on the immobilization of Pb2+ and Zn2+, in a novel approach. Heavy metals removal efficiency increased with increasing the dosage of mordenite influenced by the media-specific surface area. Heavy metals adsorption is ascribed to various mechanisms of ion exchange and adsorption processes. The Langmuir and Freundlich isotherm models were investigated using the adsorption data. The adsorption process describes better in the Freundlich isotherm model compared to the Langmuir isotherm model with a high determination co-efficient (R2), especially for the adsorption of Pb2+. In addition, the affinity of mordenite to Pb2+ was shown to be higher than that of Zn2+. This allows the use of mordenite to capture of Pb2+ in MSWI fly ash. Results raise expectations about using mordenite as a low-cost material for treating MSWI fly ashes. The results show that heavy metal (Pb2+ and Zn2+) removed by mordenite adsorbent is practical and effective. In order to achieve the higher efficiency on heavy metal stabilization in MSWI fly ash, additional experiments are necessary.

关键词： Natural Zeolite Mordenite Heavy Metals Fly ash Adsorption

Discharge Characteristics of DC Arc Water Plasma for Environmental Applications

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Plasma Science and Technology 2012年第12期14卷 1097-1101页

作者：李天明 Sooseok CHOI takayuki WATANABE Department of Environmental Chemistry and Engineering Tokyo Institute of Technology

A water plasma was generated by DC arc discharge with a hafnium embedded rodtype cathode and a nozzle-type anode. The discharge characteristics were examined by changing the operation parameter of the arc current. The dynamic behavior of the arc discharge led to significant fluctuations in the arc voltage and its frequency. Analyses of the high speed image and the arc voltage waveform showed that the arc discharge was in the restrike mode and its frequency varied within several tens of kilohertz according to the operating conditions. The larger thermal plasma volume was generated by the higher flow from the forming steam with a higher restrike frequency in the higher arc current conditions. In addition, the characteristics of the water plasma jet were investigated by means of optical emission spectroscopy to identify the abundant radicals required in an efficient waste treatment process.

关键词： thermal plasma water plasma torch arc movement restrike frequency

Decreased incidence followed by comeback of pediatric infections during the COVID‑19 pandemic in Japan

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World Journal of Pediatrics 2022年第8期18卷 564-567页

作者： Cyrus Ghaznavi Haruka Sakamoto takayuki Kawashima Sayaka Horiuchi Masahiro Ishikane Sarah Krull Abe Daisuke Yoneoka Akifumi Eguchi Yuta Tanoue Masahiro Hashizume Shuhei Nomura Department of Health Policy and Management School of MedicineKeio University35 ShinanomachiShinjuku-kuTokyo 160-8582Japan Medical Education Program Washington University School of Medicine in St.LouisSaint LouisUSA Department of Global Health Policy Graduate School of MedicineThe University of TokyoTokyoJapan Tokyo Foundation for Policy Research TokyoJapan Department of Hygiene and Public Health Tokyo Women’s Medical UniversityTokyoJapan Department of Mathematical and Computing Science Tokyo Institute of TechnologyTokyoJapan Center for Birth Cohort Studies University of YamanashiYamanashiJapan Disease Control and Prevention Center National Center for Global Health and MedicineTokyoJapan Division of Prevention National Cancer Center Institute for Cancer ControlTokyoJapan Infectious Disease Surveillance Center National Institute of Infectious DiseasesTokyoJapan Department of Sustainable Health Science Center for Preventive Medical SciencesChiba UniversityChibaJapan Institute for Business and Finance Waseda UniversityTokyoJapan

During the coronavirus disease 2019(COVID-19)pandemic,the Japanese government implemented several infection control measures,such as states of emergency(SoE)and school closures,and encouraged universal masking and hand *** activity restrictions and improved hygiene were found to be associated with declines in the incidence of infuenza during the 2019–2020 winter season[1].Prior studies have found that the incidence of seven pediatric infections,such as pharyngoconjunctivitis and varicella,decreased during and after the school closures in Japan[2].As activity restrictions continue to be lifted,there is growing concern that pediatric infections may suddenly return given that the pool of susceptible children increased during the pandemic[3].In this study,we use national infectious disease sentinel data from January 2012 to October 2021 to assess changes in the reported number of pediatric infections in Japan during the COVID-19 *** hypothesize that the reporting of many infectious diseases decreased during the early stages of the pandemic but ultimately returned to normal when activity restrictions were lifted.

关键词： closure return suddenly

Three-dimensional machining of insulating ceramics materials with electrical discharge machining

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中国有色金属学会会刊：英文版 2009年第B9期19卷 150-156页

作者： Yasushi FUKUZAWA Naotake MOHRI Hiromitsu GOTOH takayuki TANI Department of Mechanical Engineering Nagaoka University of Technology Department of Precision Engineering The University of Tokyo Department of Industrial Information Tsuku ba University of Technology

The insulating ceramics were processed with sinking and wire cut electrical discharge machining(EDM). The new technology was named as the assisting electrode method. In the machining, the electrical conductive material was adhered on the surface of insulating workpiece as the starting point of electrical discharge. As the processing operated in oil, the electrical conductive product composed of decomposition carbon element from working oil adhered on the workpiece during discharge. The discharges generated continuously with the formation of the electrical conductive layer. So, the insulating ceramics turn to the machinable material by EDM. We introduced the mechanism and the application of the machining of insulating ceramics such as Si3N4 and ZrO2.

关键词：绝缘陶瓷放电加工三维加工陶瓷材料工件表面导电材料机械加工分解过程