212 results on '"Tatsuya Kodama"'
Search Results
2. Usefulness of SMART-COP score in prognosis of aspiration pneumonia
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Tatsuya Kodama, Yoshiko Kichikawa, Norikazu Mataki, and Soichiro Kanoh
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General Medicine - Abstract
Aspiration pneumonia is becoming a common syndrome in the elderly in aging societies such as Japan. Although a number of tools have been validated for prediction of mortality in patients with community-acquired pneumonia, none have been established for aspiration pneumonia. The purpose of this study was to access the correlations of the A-DROP, CURB-65 and SMART-COP scores at the emergency visit with the 30-day mortality risk in patients with aspiration pneumonia.We Titleretrospectively investigated 210 patients who presented to the emergency department at Mishuku Hospital in Tokyo, Japan.The areas under the curve for the ability of A-DROP, Curb-65 and SMART-COP scores to predict the 30-day mortality risk were 0.6359, 0.6468 and 0.7594, respectively. Among the parameters of SMART-COP, involvement of multiple lobes on chest radiographs is the best predictor of the mortality.The SMART-COP score can be a better predictor of the 30-day mortality risk.
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- 2023
3. Characteristics of pleural effusion due to paradoxical response in patients with pulmonary tuberculosis
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Masafumi Shimoda, Takashi Yoshiyama, Yoshiaki Tanaka, Kozo Morimoto, Masao Okumura, Tatsuya Kodama, Kozo Yoshimori, and Ken Ohta
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Microbiology (medical) ,Infectious Diseases ,Pharmacology (medical) - Published
- 2023
4. Hydrogen production by solar fluidized bed reactor using ceria: Euler-Lagrange modelling of gas-solid flow to optimize the internally circulating fluidized bed
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Selvan BELLAN, Tatsuya KODAMA, Hyun SEOK CHO, and Jin-Soo KIM
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General Materials Science ,Engineering (miscellaneous) ,Instrumentation ,Atomic and Molecular Physics, and Optics - Published
- 2022
5. Fluidization behavior of redox metal oxide and spinel particles to develop high-energy-density thermal energy storage system for concentrated solar power applications
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Genta TSURUMAKI, Selvan BELLAN, Koji MATSUBARA, Tatsuya KODAMA, Mitsuho NAKAKURA, Nobuyuki GOKON, Hyun SEOK CHO, Karthik MANI, and Sakthivel SHANMUGASUNDARAM
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General Materials Science ,Engineering (miscellaneous) ,Instrumentation ,Atomic and Molecular Physics, and Optics - Published
- 2022
6. Federated learning for predicting clinical outcomes in patients with COVID-19
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Jiahui Guan, Krishna Juluru, Yothin Rakvongthai, Benjamin S. Glicksberg, Watsamon Jantarabenjakul, Li-Chen Fu, Mike Fralick, Anthony Costa, Quanzheng Li, Andrew Feng, Eric K. Oermann, Joshua D. Kaggie, Xihong Lin, Pedro Mário Cruz e Silva, Deepeksha Bhatia, Byung Seok Kim, Hitoshi Mori, Pablo F. Damasceno, Peiying Ruan, Yuhong Wen, Hao-Hsin Shin, Amilcare Gentili, Weichung Wang, Chiu-Ling Lai, Jason C. Crane, Andrew N. Priest, Soo-Young Park, Peerapon Vateekul, Matheus Ribeiro Furtado de Mendonça, Gustavo César de Antônio Corradi, Griffin Lacey, Meena AbdelMaseeh, Yu Rim Lee, Tatsuya Kodama, Pierre Elnajjar, Krishna Nand Keshava Murthy, Xiang Li, Evan Leibovitz, Vitor Lavor, Christopher P. Hess, Colin B. Compas, Stefan Gräf, Masoom A. Haider, Daguang Xu, Nicola Rieke, Thanyawee Puthanakit, Sarah E Hickman, Hui Ren, Marcio Aloisio Bezerra Cavalcanti Rockenbach, Jung Gil Park, Jesse Tetreault, Hisashi Sasaki, Min Kyu Kang, Won Young Tak, Chun-Nan Hsu, Fiona J. Gilbert, Chin Lin, Varun Buch, Felipe Kitamura, Tony Mazzulli, Eddie Huang, Abood Quraini, Shelley McLeod, Young Joon Kwon, Gustavo Nino, Dufan Wu, Chien-Sung Tsai, Mona Flores, Baris Turkbey, Sira Sriswasdi, Pochuan Wang, Mohammad Adil, Aoxiao Zhong, Chih-Hung Wang, Sheng Xu, C. K. Lee, Isaac Yang, Marius George Linguraru, Holger R. Roth, Chia-Jung Hsu, Anas Z. Abidin, Thomas M. Grist, Hirofumi Obinata, Sheridan Reed, Andrew Liu, Ahmed Harouni, Natalie Gangai, Ittai Dayan, Kristopher Kersten, Stephanie Harmon, Jae Ho Sohn, John Garrett, Bradford J. Wood, Sharmila Majumdar, Bernardo Bizzo, Shuichi Kawano, Keith J. Dreyer, Carlos Tor-Díez, and Chia-Cheng Lee
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medicine.medical_specialty ,Information privacy ,Coronavirus disease 2019 (COVID-19) ,Computer science ,business.industry ,Vital signs ,General Medicine ,General Biochemistry, Genetics and Molecular Biology ,Data sharing ,Data exchange ,Health care ,medicine ,Generalizability theory ,Medical physics ,In patient ,business - Abstract
Federated learning (FL) is a method used for training artificial intelligence models with data from multiple sources while maintaining data anonymity, thus removing many barriers to data sharing. Here we used data from 20 institutes across the globe to train a FL model, called EXAM (electronic medical record (EMR) chest X-ray AI model), that predicts the future oxygen requirements of symptomatic patients with COVID-19 using inputs of vital signs, laboratory data and chest X-rays. EXAM achieved an average area under the curve (AUC) >0.92 for predicting outcomes at 24 and 72 h from the time of initial presentation to the emergency room, and it provided 16% improvement in average AUC measured across all participating sites and an average increase in generalizability of 38% when compared with models trained at a single site using that site’s data. For prediction of mechanical ventilation treatment or death at 24 h at the largest independent test site, EXAM achieved a sensitivity of 0.950 and specificity of 0.882. In this study, FL facilitated rapid data science collaboration without data exchange and generated a model that generalized across heterogeneous, unharmonized datasets for prediction of clinical outcomes in patients with COVID-19, setting the stage for the broader use of FL in healthcare. Federated learning, a method for training artificial intelligence algorithms that protects data privacy, was used to predict future oxygen requirements of symptomatic patients with COVID-19 using data from 20 different institutes across the globe.
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- 2021
7. Experimental Study of Thermochemical Two-step Water Splitting Cycle for Hydrogen by Fe-CeO2 Redox Metal Oxide Coated foam Device with 3kWth Sun-simulator
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Yu Sakai, Hyun Seok Cho, and Tatsuya Kodama
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Materials science ,Hydrogen ,Two step ,Oxide ,chemistry.chemical_element ,Redox ,Metal ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,visual_art ,visual_art.visual_art_medium ,Water splitting ,Solar simulator - Published
- 2021
8. Myxovirus resistance protein A in peripheral blood predicts supplemental oxygen need in COVID-19
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Satoko Nakamura, Sakiko Tabata, Kazuyasu Miyoshi, Shuichi Kawano, Kouichi Nishimura, Yoshiko Kichikawa, Michio Nakai, Mayu Nagura, Shigeaki Aono, Toshimitsu Ito, Norikazu Mataki, Yasuhide Uwabe, Tatsuya Kodama, Hiroki Ohmura, Satoshi Mimura, and Hisashi Sasaki
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Microbiology (medical) ,biology ,Coronavirus disease 2019 (COVID-19) ,Supplemental oxygen ,business.industry ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,Point-of-care testing ,Orthomyxoviridae ,chemistry.chemical_element ,Pharmacology ,biology.organism_classification ,Oxygen ,Peripheral blood ,Infectious Diseases ,chemistry ,biology.protein ,Medicine ,business ,Protein A - Published
- 2021
9. A review on high‐temperature thermochemical heat storage: Particle reactors and materials based on solid–gas reactions
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Selvan Bellan, Tatsuya Kodama, Nobuyuki Gokon, and Koji Matsubara
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Renewable Energy, Sustainability and the Environment ,General Environmental Science - Published
- 2022
10. Direct simulation of a volumetric solar receiver with different cell sizes at high outlet temperatures (1,000–1,500 °C)
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Mitsuho Nakakura, Koji Matsubara, Tatsuya Kodama, and Selvan Bellan
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Convection ,Materials science ,060102 archaeology ,Renewable Energy, Sustainability and the Environment ,020209 energy ,Numerical analysis ,Direct numerical simulation ,Flux ,06 humanities and the arts ,02 engineering and technology ,Mechanics ,Radiation ,Air mass (solar energy) ,Thermal conduction ,Thermal ,0202 electrical engineering, electronic engineering, information engineering ,0601 history and archaeology - Abstract
This paper describes and presents the direct numerical simulation of a volumetric solar receiver under concentrated irradiation. The simulations systematically analyze the receiver performance and thermal loss mechanisms for operating conditions when outlet temperatures are in the 1000–1500 °C range. The implemented numerical method fully considers interactions between radiation, convection, and conduction using a discrete ordinates approach as a radiation model. The power over air mass (POM) and air mass flux were modified for six receiver channels with different cell sizes. The receiver efficiency decreased when the air mass flux increased beyond a certain criterion for constant POM. For a 3.8 mm cell, the receiver efficiency decreased to
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- 2020
11. Theoretical Material Research with First Principle Calculation Aiming at High-efficiency Hydrogen Production Using Solar Thermochemical Energy
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Ishii Tomohiko, Takaki Nishimura, Tatsuya Kodama, and Sakane Genta
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In recent years, hydrogen energy has been attracting attention, and the hydrogen gas production using solar thermal energy has been conducted. The studies of Kodama et al. were reported that the cyclic reaction can efficiently produce the hydrogen gas through a two-step thermal redox reaction with the cerium oxide. The transition metal doping into the cerium oxide improved the reaction efficiency. In our work, we considered the doping effect on the thermal two-step redox reaction. As a result of the calculation by the DV-Xα method, it was clarified that the doped cerium oxide becomes a strong bond, the large BOP value without changing the ceria crystal structure in the two-step thermal redox reaction. The theoretical calculation results corresponded to the reaction efficiency improvement of the thermal reaction in experimental results.
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- 2022
12. Transition metals doped effects for the crystal stabilization of the cerium oxides with the first principle calculation
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Takaki Nishimura, Tatsuya Kodama, Sakane Genta, and Tomohiko Ishii
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Multidisciplinary - Abstract
In recent years, hydrogen energy has been attracting attention, and the hydrogen gas production using solar thermal energy has been conducted. The studies of Kodama et al. were reported that the cyclic reaction can efficiently produce the hydrogen gas through a two-step thermal redox reaction with the cerium oxide. The transition metal doping into the cerium oxide improved the reaction efficiency. We considered the doping effect on the thermal two-step redox reaction. As a result of the calculation by the DV-Xα method, it was clarified that the doped cerium oxide becomes a strong bond, the large BOP value without changing the ceria crystal structure in the two-step thermal redox reaction. The theoretical calculation results corresponded to the reaction efficiency improvement of the thermal reaction in experimental results.
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- 2022
13. Development of Synthesis and Fabrication Process for Mn-CeO2 Foam via Two-Step Water-Splitting Cycle Hydrogen Production
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Selvan Bellan, Hyun Seok Cho, Jong Kyu Kim, Tatsuya Kodama, and Nobuyuki Gokon
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Technology ,Control and Optimization ,Materials science ,Hydrogen ,Coprecipitation ,Oxide ,Energy Engineering and Power Technology ,chemistry.chemical_element ,doping ,engineering.material ,chemistry.chemical_compound ,Coating ,solar fuel ,hydrogen ,two-step water-splitting cycle ,ceria ,cerium oxide ,direct depositing method ,Electrical and Electronic Engineering ,Engineering (miscellaneous) ,Hydrogen production ,Ceramic foam ,Spin coating ,Renewable Energy, Sustainability and the Environment ,Chemical engineering ,chemistry ,engineering ,Water splitting ,Energy (miscellaneous) - Abstract
The effects of doping manganese ions into a cerium oxide lattice for a thermochemical two-step water-splitting cycle to produce oxygen and hydrogen and new synthesis methods were experimentally investigated. In order to comparison of oxygen/hydrogen producing performance, pristine CeO2, a coprecipitation method for Mn-CeO2, and a direct depositing method for Mn-CeO2 with different particle sizes (50~75, 100–212, over 212 μm) and doping extents (0, 5, 15 mol%) were tested in the context of synthesis and fabrication processes of reactive metal oxide coated ceramic foam devices. Sample powders were coated onto zirconia (magnesium partially stabilized zirconia oxide, MPSZ) porous foam at 30 weight percent using spin coating or a direct depositing method, tested using a solar reactor at 1400 °C as a thermal reduction step and at 1200 °C as a water decomposition step for five repeated cycles. The sample foam devices were irradiated using a 3-kWth sun-simulator, and all reactive foam devices recorded successful oxygen/hydrogen production using the two-step water-splitting cycles. Among the seven sample devices, the 5 mol% Mn-CeO2 foam device, that synthesized using the coprecipitation method, showed the greatest hydrogen production. The newly suggested direct depositing method, with its contemporaneous synthesis and coating of the Mn-CeO2 foam device, showed successful oxygen/hydrogen production with a reduction in the manufacturing time and reactants, which was lossless compared to conventional spin coating processes. However, proposed direct depositing method still needs further investigation to improve its stability and long-term device durability.
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- 2021
14. Cilia‐Mediated Insulin/Akt and ST2/JNK Signaling Pathways Regulate the Recovery of Muscle Injury
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Daishi Yamakawa, Junya Tsuboi, Kousuke Kasahara, Chise Matsuda, Yuhei Nishimura, Tatsuya Kodama, Naoyuki Katayama, Masatoshi Watanabe, and Masaki Inagaki
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General Chemical Engineering ,General Engineering ,General Physics and Astronomy ,Medicine (miscellaneous) ,General Materials Science ,Biochemistry, Genetics and Molecular Biology (miscellaneous) - Abstract
Following injury, skeletal muscle regenerates but fatty tissue accumulation is seen in aged muscle or muscular dystrophies. Fibro/adipogenic progenitors (FAPs) are key players in these events; however, the effect of primary cilia on FAPs remains unclear. Here, it is reported that genetic ablation of trichoplein (TCHP), a ciliary regulator, induces ciliary elongation on FAPs after injury, which promotes muscle regeneration while inhibiting adipogenesis. The defective adipogenic differentiation of FAPs is attributed to dysfunction of cilia-dependent lipid raft dynamics, which is critical for insulin/Akt signaling. It is also found that interleukin (IL) 13 is substantially produced by intramuscular FAPs, which are upregulated by ciliary elongation and contribute to regeneration. Mechanistically, upon injury, long cilia excessively activate the IL33/ST2/JNK axis to enhance IL13 production, facilitating myoblast proliferation and M2 macrophage polarization. The results indicate that FAPs organize the regenerative responses to skeletal muscle injury via cilia-mediated insulin/Akt and ST2/JNK signaling pathways.
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- 2022
15. Efficacy of Chest Radiography as a Primary Care Triage Tool in Severe Coronavirus Disease
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Kaku Tamura, Hiroaki Taniguchi, Hirofumi Obinata, Yasuhide Uwabe, Toshimitsu Ito, Shuichi Kawano, Hisashi Sasaki, Tatsuya Kodama, and Shinichiro Ota
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Male ,medicine.medical_specialty ,Radiography ,medicine.medical_treatment ,severity ,Likelihood ratios in diagnostic testing ,Group B ,Internal medicine ,Oxygen therapy ,Internal Medicine ,medicine ,Humans ,Retrospective Studies ,Lung ,Primary Health Care ,business.industry ,SARS-CoV-2 ,COVID-19 ,Retrospective cohort study ,General Medicine ,Middle Aged ,Triage ,chest X-ray ,medicine.anatomical_structure ,coronavirus disease ,Radiological weapon ,Radiography, Thoracic ,Original Article ,business ,severe acute respiratory syndrome coronavirus 2 - Abstract
Objective Severe acute respiratory syndrome coronavirus 2 has spread globally, and it is important to utilize medical resources properly, especially in critically ill patients. We investigated the validity of chest radiography as a tool for predicting aggravation in coronavirus disease (COVID-19) cases. Methods A total of 104 laboratory-confirmed COVID-19 cases were referred from the cruise ship "Diamond Princess" to the Self-Defense Forces Central Hospital in Japan from February 11 to 25, 2020. Fifty-nine symptomatic patients were selected. Chest radiography was performed upon hospitalization; subsequently, patients were categorized into the positive radiograph (Group A) and negative radiograph (Group B) groups. Radiographic findings were analyzed with a six-point semiquantitative score. Group A was further classified into two additional subgroups: patients who required oxygen therapy during their clinical courses (Group C) and patients who did not (Group D). Clinical records, laboratory data, and radiological findings were collected for an analysis. Results Among 59 patients, 34 were men with a median age of 60 years old. Groups A, B, C, and D consisted of 33, 26, 12, and 21 patients, respectively. The number of patients requiring oxygen administration was significantly larger in Group A than in Group B. The consolidation score on chest radiographs was significantly higher in Group C than in Group D. When chest radiographs showed consolidation in more than two lung fields, the positive likelihood ratio of deterioration was 10.6. Conclusions Chest radiography is a simple and easy-to-use clinic-level triage tool for predicting the severity of COVID-19 and may contribute to the allocation of medical resources.
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- 2021
16. Phase Change Material of Copper–Germanium Alloy as Solar Latent Heat Storage at High Temperatures
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Shogo Okazaki, Chew Shun Jie, Tsuyoshi Hatamachi, Selvan Bellan, Yuya Nakano, Nobuyuki Gokon, and Tatsuya Kodama
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Economics and Econometrics ,Materials science ,020209 energy ,Alloy ,Energy Engineering and Power Technology ,chemistry.chemical_element ,Germanium ,latent heat ,copper-germanium alloy ,02 engineering and technology ,engineering.material ,01 natural sciences ,General Works ,Laser flash analysis ,concentrated solar power ,chemistry.chemical_compound ,Differential scanning calorimetry ,thermal storage system ,Thermal ,0202 electrical engineering, electronic engineering, information engineering ,Silicon carbide ,Composite material ,Renewable Energy, Sustainability and the Environment ,Phase-change material ,010406 physical chemistry ,0104 chemical sciences ,Fuel Technology ,chemistry ,engineering ,Thermomechanical analysis ,phase change material - Abstract
A copper–germanium alloy (Cu–Ge alloy) was examined as a phase change material, at temperatures exceeding 600°C, for latent heat storage in solar thermal applications. First, the thermo-physical properties of the Cu–Ge alloy were examined using differential scanning calorimetry, thermomechanical analysis, and laser flash analysis. Second, to evaluate the thermal response and reliability of the Cu–Ge alloy, the cyclic properties of thermal charge/discharge were examined under various thermal conditions. The alloys obtained after the tests were examined for their chemical compatibility with the stainless steel container using an electron probe micro analyzer. The elemental distribution of each Cu–Ge alloy was evaluated using cyclic performance tests. Finally, the chemical compatibility of the Cu–Ge alloy was evaluated using a high-temperature test with candidate materials of a phase change material container vessel [stainless steel (SUS310S), Inconel625, silicon carbide (SiC), and alumina (Al2O3)]. The Cu–Ge alloy exhibited significant potential as a latent heat storage material in next-generation solar thermal power plants because it demonstrates various advantages, including a superior storage capacity at a temperature of 644°C, temperature coherence to the phase diagram, a quick thermal response, satisfactory cyclic behavior of charge/discharge modes, a thermodynamically stable metallographic structure, and non-reactivity with container ceramic materials (SiC and Al2O3).
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- 2021
17. Heat transfer and particulate flow analysis of a 30 kW directly irradiated solar fluidized bed reactor for thermochemical cycling
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Tatsuya Kodama, Kousuke Inoue, Nobuyuki Gokon, Koji Matsubara, Hyun Seok Cho, and Selvan Bellan
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Convection ,Materials science ,Applied Mathematics ,General Chemical Engineering ,Nuclear engineering ,General Chemistry ,Industrial and Manufacturing Engineering ,Discrete element method ,Volumetric flow rate ,Fluidized bed ,Mass transfer ,Heat transfer ,Radiative transfer ,Thermochemical cycle - Abstract
To perform thermochemical cycles using non-volatile metal oxides to split water and produce hydrogen, a directly irradiated fluidized bed reactor is designed and fabricated for beam-down configuration. As the main aim of this investigation is to analyze the heat transfer and particulate flow of the reactor, chemically inert particles are used. A transient 3D heat and mass transfer model is formulated by the combined approach of discrete element method and computational fluid dynamics. The radiative transfer is solved using the discrete ordinate radiation model. Experimental validation is accomplished by the measured temperatures, obtained with the fluidized bed reactor prototype tested under 30 kWth high-flux solar simulator. The model is applied to analyze the granular flow characteristics and efficiency of the reactor for various superficial gas velocities and bed masses. The results indicate that higher gas flow rate increases the velocity and convection loss of the bed and decreases the bed temperature and efficiency of the reactor.
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- 2019
18. Thermal performance of a 30 kW fluidized bed reactor for solar gasification: A CFD-DEM study
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Kousuke Inoue, Nobuyuki Gokon, Tatsuya Kodama, Selvan Bellan, Koji Matsubara, and Hyun Seok Cho
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Materials science ,General Chemical Engineering ,Nuclear engineering ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Industrial and Manufacturing Engineering ,Discrete element method ,0104 chemical sciences ,Volumetric flow rate ,Thermal radiation ,Fluidized bed ,Thermal ,Heat transfer ,Environmental Chemistry ,Solar simulator ,0210 nano-technology ,CFD-DEM - Abstract
Gasification of carbonaceous materials using concentrated solar thermal radiation has been considered as one of the promising renewable pathways to produce syngas. In this study, thermal performance of a recently developed solar thermochemical reactor is presented. To analyze the gas–solid flow and heat transfer characteristics of the reactor, a transient three dimensional numerical model has been developed using discrete element method and computational fluid dynamics. Particle collision dynamics has been solved by the spring-dashpot model based on the soft-sphere method. To perform model verification, experiments have been performed using 30kWth fluidized bed reactor prototype under high flux solar simulator. The particulate and thermal characteristics of spout, annulus and fountain of the fluidized bed are analyzed for different irradiation power, loaded powder and gas flow rates. The results indicate that large and small size particles govern the bottom and fountain part of the bed respectively due to gravitational force, and the peak temperature is moved from fountain core to the fountain periphery of the bed when increasing the gas flow rate.
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- 2019
19. Thermochemical behavior of perovskite oxides based on LaxSr1-x(Mn, Fe, Co)O3-δ and BaySr1-yCoO3-δ redox system for thermochemical energy storage at high temperatures
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Nobuyuki Gokon, Takehiro Yawata, Hyun Seok Cho, Tatsuya Kodama, and Selvan Bellan
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Thermogravimetric analysis ,Materials science ,020209 energy ,Mechanical Engineering ,Enthalpy ,Oxide ,02 engineering and technology ,Building and Construction ,Pollution ,Redox ,Industrial and Manufacturing Engineering ,Energy storage ,chemistry.chemical_compound ,General Energy ,Differential scanning calorimetry ,020401 chemical engineering ,chemistry ,Chemical engineering ,0202 electrical engineering, electronic engineering, information engineering ,Reactivity (chemistry) ,0204 chemical engineering ,Electrical and Electronic Engineering ,Civil and Structural Engineering ,Perovskite (structure) - Abstract
LaxSr1-x(Mn, Fe, Co)O3-δ, and BaySr1-yCoO3-δ perovskite oxide powders were investigated as potential thermochemical energy storage (TES) materials operated at high temperatures above 600 °C. The purpose of the research is to provide complete characterization of the impact of partial A- and B-site substitution on the reactivity, kinetics, redox reaction repeatability and charging/discharging storage capacity. The perovskite oxides were investigated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) at temperatures of 500–1100 °C. Thermal energy storage was evaluated in terms of the enthalpy of the reversible reactions of oxygen release (reduction) and uptake (oxidation) upon heating the oxide materials in air stream. Among the perovskites tested, Ba0.3Sr0.7CoO3-δ and Ba0.7Sr0.3CoO3-δ powders were suitable thermochemical storage materials operating at above 600 °C in terms of chemical reactivity, charging/discharging temperatures and storage capacities, kinetics of oxygen uptake/release, and repeatability of thermochemical cycling. Further, charging/discharging capacity for both perovskites was comparable to that for Fe-doped manganese oxide.
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- 2019
20. Development of a 5kWth internally circulating fluidized bed reactor containing quartz sand for continuously-fed coal-coke gasification and a beam-down solar concentrating system
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Nobuyuki Gokon, Satoshi Kumaki, Selvan Bellan, Tatsuya Kodama, Hyun Seok Cho, and Yosuke Miyaguchi
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Materials science ,020209 energy ,Distributor ,02 engineering and technology ,Thermal energy storage ,Industrial and Manufacturing Engineering ,law.invention ,020401 chemical engineering ,law ,0202 electrical engineering, electronic engineering, information engineering ,Coal ,Xenon arc lamp ,Fluidized bed combustion ,0204 chemical engineering ,Electrical and Electronic Engineering ,Quartz ,Civil and Structural Engineering ,business.industry ,Mechanical Engineering ,Metallurgy ,Building and Construction ,Coke ,Pollution ,General Energy ,Fluidized bed ,business - Abstract
The operational mode of a batch-type fluidized bed reactor containing quartz sand and coal-coke particles was tested under xenon arc lamp (Xe-light) illumination to develop processes for the continuous feeding and gasification of coke particles in the quartz sand fluidized bed. This paper focuses on the fluidizing, heating, and steam gasification performances of a windowed internally circulating fluidized bed reactor. The operational modes explored in this study were: (1) elevated temperature processes associated with the use of Xe-light radiation to reach gasification temperatures, and, (2) the gasification process driving steam gasification at high-temperatures, working with stream gasification of continuously-fed coal-coke. The gasification performances were used to evaluate the performance of quartz sand as a thermal-transfer/sensible heat-storage medium. The peak rate of gas production was greatly enhanced for the high volume fraction of coal-coke. In addition, the light-to-energy conversion rate of 11.0–13.2% and carbon conversion rate up to 80% were reached in the simplified distributor structure of gasification reactor.
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- 2019
21. Multiple infected lung bullae associated with Mycobacterium intracellulare in a Japanese man
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Hiroyuki Kokuto, Tatsuya Kodama, and Atsushi Kurokawa
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Pulmonary and Respiratory Medicine ,Pathology ,medicine.medical_specialty ,Percutaneous ,Case Report ,Case Reports ,Chest pain ,03 medical and health sciences ,0302 clinical medicine ,medicine ,tetralogy of Fallot ,Bulla (seal) ,Tetralogy of Fallot ,lcsh:RC705-779 ,Lung ,biology ,business.industry ,lcsh:Diseases of the respiratory system ,biology.organism_classification ,medicine.disease ,Infected lung bulla ,Mycobacterium intracellulare ,medicine.anatomical_structure ,030228 respiratory system ,030220 oncology & carcinogenesis ,Lung bullae ,medicine.symptom ,business ,Mycobacterium ,Right upper lobe bronchus - Abstract
Mycobacterium avium complex (MAC)‐infected lung bulla was a rare type of pulmonary non‐tuberculous mycobacterial (NTM) infection. A 29‐year‐old man with a history of tetralogy of Fallot was admitted to our hospital because of a high fever and left chest pain. Chest computed tomography showed two bullae with intrabullous fluid in both the lower lobes and centrilobular small nodular shadow in the right upper lobe and the left lower lobe. Culture of bronchoscopic washing specimen from the right upper lobe bronchus and left lower lobe one and purulent fluid drained from the bulla in the left lower lobe revealed Mycobacterium intracellulare. Percutaneous drainage from the left bulla and anti‐NTM treatment were performed. Afterwards, symptoms improved and two intrabullous fluid disappeared. Therefore, a diagnosis of multiple infected lung bullae associated with M. intracellulare was made. This is the first documented case of multiple infected lung bullae associated with MAC., Here, we report the first documented case of multiple infected lung bullae associated with Mycobacterium avium complex (MAC) in a 29‐year‐old man.
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- 2021
22. Prediction of an increase in oxygen requirement of SARS-CoV-2 pneumonia using three different scoring systems
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Hitoshi Mori, Akihiko Kawana, Hisashi Sasaki, Satoshi Mimura, Yohsuke Suyama, Hirofumi Obinata, Wakana Murakami, Shuichi Kawano, Yuji Kouzaki, and Tatsuya Kodama
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0301 basic medicine ,Male ,Severity of Illness Index ,0302 clinical medicine ,Risk Factors ,Risk of mortality ,Pharmacology (medical) ,030212 general & internal medicine ,health care economics and organizations ,CURB-65 ,Middle Aged ,Prognosis ,humanities ,C-Reactive Protein ,Infectious Diseases ,Original Article ,Female ,Respiratory Insufficiency ,geographic locations ,Adult ,Microbiology (medical) ,medicine.medical_specialty ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,education ,030106 microbiology ,Pneumonia, Viral ,SARS-CoV-2 pneumonia ,Fibrin Fibrinogen Degradation Products ,03 medical and health sciences ,Internal medicine ,Lymphopenia ,Severity of illness ,medicine ,A-DROP ,Humans ,Tokyo ,Aged ,Retrospective Studies ,business.industry ,SARS-CoV-2 ,Oxygen Inhalation Therapy ,COVID-19 ,Retrospective cohort study ,medicine.disease ,Expanded CURB-65 ,Pneumonia ,Respiratory failure ,Lymphocytopenia ,business ,Tomography, X-Ray Computed - Abstract
Introduction In patients with severe coronavirus disease 2019 (COVID-19), respiratory failure is a major complication and its symptoms occur around one week after onset. The CURB-65, A-DROP and expanded CURB-65 tools are known to predict the risk of mortality in patients with community-acquired pneumonia. In this retrospective single-center retrospective study, we aimed to assess the correlations of the A-DROP, CURB-65, and expanded CURB-65 scores on admission with an increase in oxygen requirement in patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pneumonia. Methods We retrospectively analyzed 207 patients who were hospitalized with SARS-CoV-2 pneumonia at the Self-Defense Forces Central Hospital in Tokyo, Japan. Performance of A-DROP, CURB-65, and the expanded CURB-65 scores were validated. In addition, we assessed whether there were any associations between an increase in oxygen requirement and known risk factors for critical illness in COVID-19, including elevation of liver enzymes and C-reactive protein (CRP), lymphocytopenia, high D-dimer levels and the chest computed tomography (CT) score. Results The areas under the curve for the ability of CURB-65, A-DROP, and the expanded CURB-65 scores to predict an increase in oxygen requirement were 0.6961, 0.6980 and 0.8327, respectively, and the differences between the three groups were statistically significant (p
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- 2021
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23. Federated Learning used for predicting outcomes in SARS-COV-2 patients
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Matheus Ribeiro Furtado de Mendonça, Evan Leibovitz, Kristopher Kersten, Mona Flores, John Garrett, Baris Turkbey, Pablo F. Damasceno, Masoom A. Haider, Fred Kwon, Soo-Young Park, Chun-Nan Hsu, Keith J. Dreyer, Chien-Sung Tsai, Tatsuya Kodama, Daguang Xu, Min Kyu Kang, Tony Mazzulli, Andrew Feng, C. K. Lee, Isaac Yang, Deepi Bhatia, Marius George Linguraru, Byung Seok Kim, Aoxiao Zhong, Mohammad Adil, Pochuan Wang, Sheridan Reed, Peerapon Vateekul, Anas Z. Abidin, Sira Sriswa, J. D. Kaggie, Chia-Cheng Lee, Carlos Tor-Díez, Krishna Juluru, Xiang Li, Colin B. Compas, Xihong Lin, Jiahui Guan, Pierre Elnajjar, Yuhong Wen, Jung Gil Park, Hao-Hsin Shin, Amilcare Gentili, Weichung Wang, Colleen Ruan, Hui Ren, Hisashi Sasaki, Hitoshi Mori, Holger R. Roth, Felipe Kitamura, Chiu-Ling Lai, Jason C. Crane, Thomas M. Grist, Bradford J. Wood, Bernardo Bizzo, Dufan Wu, Jesse Tetreault, Andrew N. Priest, Mike Fralick, Anthony Costa, Andrew Liu, Benjamin S. Glicksberg, Griffin Lacey, Meena Abdelmaseeh, Thanyawee Puthanakit, Marcio Aloisio Bezerra Cavalcanti Rockenbach, Shelley McLeod, Pedro Mário Cruz e Silva, Chih-Hung Wang, Chia-Jung Hsu, Sarah E Hickman, Won Young Tak, Quanzheng Li, Yothin Rakvongthai, Watsamon Jantarabenjakul, Li-Chen Fu, Gustavo César de Antônio Corradi, Eric K. Oermann, Nicola Rieke, Varun Buch, Abood Quraini, Shuichi Kawano, Natalie Gangai, Yu Rim Lee, Krishna Nand Keshava Murthy, Christopher P. Hess, Stefan Gräf, Ittai Dayan, Stephanie Harmon, Jae Ho Sohn, Eddie Huang, Ahmed Harouni, Vitor de Lima Lavor, Sharmila Majumdar, Sheng Xu, Hirofumi Obinata, Fiona J. Gilbert, and Chin Lin
- Subjects
federated learning ,Computer science ,business.industry ,SARS-CoV-2 ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,Vital signs ,MEDLINE ,COVID-19 ,artificial intelligence ,Prognosis ,Data science ,Article ,Data sharing ,Machine Learning ,Data exchange ,Health care ,Outcome Assessment, Health Care ,Electronic Health Records ,Humans ,Set (psychology) ,business ,Anonymity - Abstract
Federated learning (FL) is a method used for training artificial intelligence models with data from multiple sources while maintaining data anonymity, thus removing many barriers to data sharing. Here we used data from 20 institutes across the globe to train a FL model, called EXAM (electronic medical record (EMR) chest X-ray AI model), that predicts the future oxygen requirements of symptomatic patients with COVID-19 using inputs of vital signs, laboratory data and chest X-rays. EXAM achieved an average area under the curve (AUC)0.92 for predicting outcomes at 24 and 72 h from the time of initial presentation to the emergency room, and it provided 16% improvement in average AUC measured across all participating sites and an average increase in generalizability of 38% when compared with models trained at a single site using that site's data. For prediction of mechanical ventilation treatment or death at 24 h at the largest independent test site, EXAM achieved a sensitivity of 0.950 and specificity of 0.882. In this study, FL facilitated rapid data science collaboration without data exchange and generated a model that generalized across heterogeneous, unharmonized datasets for prediction of clinical outcomes in patients with COVID-19, setting the stage for the broader use of FL in healthcare.
- Published
- 2021
24. Clinical characteristics of COVID-19 in 104 people with SARS-CoV-2 infection on the Diamond Princess cruise ship: a retrospective analysis
- Author
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Yasuhide Uwabe, Shuichi Kawano, Kaku Tamura, Satoshi Mimura, Michiya Sato, Manabu Kitagaki, Kazuo Imai, Sakiko Tabata, Satoshi Suzuki, Tatsuya Kodama, Kazuyasu Miyoshi, Mayu Ikeda, Hirofumi Obinata, Toshimitsu Ito, and Tsutomu Kodera
- Subjects
0301 basic medicine ,medicine.medical_specialty ,Coronavirus disease 2019 (COVID-19) ,business.industry ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,Disease progression ,Retrospective cohort study ,Odds ratio ,medicine.disease ,Asymptomatic ,03 medical and health sciences ,Pneumonia ,030104 developmental biology ,0302 clinical medicine ,Infectious Diseases ,Internal medicine ,Radiological weapon ,medicine ,030212 general & internal medicine ,medicine.symptom ,business - Abstract
Background The ongoing COVID-19 pandemic is a global threat. Identification of markers for symptom onset and disease progression is a pressing issue. We described the clinical features of people infected on board the Diamond Princess cruise ship who were diagnosed with asymptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection or mild or severe COVID-19, on admission to the Self-Defense Forces Central Hospital (Tokyo, Japan) and at the end of observation. Methods This retrospective, single-centre study included participants with laboratory-detected SARS-CoV-2 infection who were admitted to the Self-Defense Forces Central Hospital from Feb 11 to Feb 25, 2020. Clinical records, laboratory data, and radiological findings were analysed. Clinical outcomes were followed up until discharge or Feb 26, 2020, whichever came first. We defined asymptomatic infection as SARS-CoV-2 infection with no history of clinical signs and symptoms, severe COVID-19 as clinical symptoms of pneumonia (dyspnoea, tachypnoea, peripheral capillary oxygen saturation Findings Among the 104 participants included in the final analysis, the median age was 68 years (IQR 47-75) and 54 (52%) were male. On admission, 43 (41%) participants were classified as asymptomatic, 41 (39%) as having mild COVID-10, and 20 (19%) as having severe COVID-19. At the end of observation, 33 (32%) participants were confirmed as being asymptomatic, 43 (41%) as having mild COVID-19, and 28 (27%) as having severe COVID-19. Serum lactate hydrogenase concentrations were significantly higher in the ten participants who were asymptomatic on admission but developed symptomatic COVID-19 compared with the 33 participants who remained asymptomatic throughout the observation period (five [50%] vs four [12%] participants; odds ratio 7·25, 95% CI 1·43-36·70; p=0·020). Compared with patients with mild disease at the end of observation, patients with severe COVID-19 were older (median age 73 years [IQR 55-77] vs 60 years [40-71]; p=0·028) and had more frequent consolidation on chest CT (13 [46%] of 28 vs nine [21%] of 43; p=0·035) and lymphopenia (16 [57%] vs ten [23%]; p=0·0055) on admission. Interpretation Older age, consolidation on chest CT images, and lymphopenia might be risk factors for disease progression of COVID-19 and contribute to improved clinical management. Funding None.
- Published
- 2020
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25. Serial serum SARS-CoV-2 RNA results in two COVID-19 cases with severe respiratory failure
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Akihiko Kawana, Hisashi Sasaki, Hiroaki Taniguchi, Shinichiro Ota, Yuji Kouzaki, Hirofumi Obinata, Tatsuya Kodama, Kaku Tamura, and Shuichi Kawano
- Subjects
0301 basic medicine ,Microbiology (medical) ,medicine.medical_specialty ,Coronavirus disease 2019 (COVID-19) ,030106 microbiology ,Viremia ,serum SARS-CoV-2 RNA ,Article ,law.invention ,03 medical and health sciences ,0302 clinical medicine ,law ,Internal medicine ,Severity of illness ,medicine ,Pharmacology (medical) ,030212 general & internal medicine ,Polymerase chain reaction ,Predictive marker ,business.industry ,RNA ,COVID-19 ,Retrospective cohort study ,medicine.disease ,Infectious Diseases ,Respiratory failure ,severe respiratory failure ,business - Abstract
Coronavirus disease 2019 (COVID-19) is spreading worldwide and poses an imminent threat to public health. We encountered 2 cases of COVID-19 with progression resulting in severe respiratory failure and improvement without any specific treatment. To examine the course of infection, we performed reverse-transcription (RT) polymerase chain reaction assay with serum specimens, and serum SARS-CoV-2 RNA was detected in both cases when body temperature increased and respiratory status deteriorated. We, then examined, retrospectively and prospectively, the clinical course during hospitalization by performing serial examinations of serum SARS-CoV-2 RNA status. The findings from our cases suggest that not only is detection of viremia useful as a predictive marker of severity, but also serial serum SARS-CoV-2 RNA results can be helpful for predicting the clinical course.
- Published
- 2020
26. Thermochemical two-step CO2 splitting using La0.7Sr0.3Mn0.9Cr0.1O3 of perovskite oxide for solar fuel production
- Author
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Hyun Seok Cho, Selvan Bellan, Hiroki Sawaguri, Nobuyuki Gokon, Tatsuya Kodama, and Naoki Ito
- Subjects
chemistry.chemical_compound ,Materials science ,chemistry ,Chemical engineering ,Hydrogen ,Oxide ,chemistry.chemical_element ,Reactivity (chemistry) ,Solar fuel ,Oxygen ,Redox ,Perovskite (structure) ,Carbon monoxide - Abstract
A thermochemical two-step water-splitting cycle using perovskite oxide of La0.7Sr0.3Mn0.9Cr0.1O3 was examined for carbon monoxide production from CO2 using concentrated solar radiation. Previously, the authors proved the perovskite oxide can thermochmically split H2O via two-step process into oxygen and hydrogen in an individual step. In this study, a thermochemical two-step CO2 splitting cycle using the perovskite oxide was examined for the reactivity and repeatability of redox reaction at CO2 spitting temperatures of 1000-1200 °C. The reactivity and repeatability for two-step CO2 splitting was compared to those for H2O splitting operating at the same temperature level.
- Published
- 2020
27. Non-Severe vs Severe Symptomatic COVID-19: 104 Cases from the Outbreak on the Cruise Ship 'Diamond Princess' in Japan
- Author
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Satoshi Suzuki, Tatsuya Kodama, Kazuyasu Miyoshi, Toshimitsu Ito, Sakiko Tabata, Michiya Sato, Mayu Ikeda, Manabu Kitagaki, Kaku Tamura, Kazuo Imai, Yasuhide Uwabe, Tsutomu Kodera, Hirofumi Obinata, Shuichi Kawano, and Satoshi Mimura
- Subjects
Pediatrics ,medicine.medical_specialty ,Coronavirus disease 2019 (COVID-19) ,business.industry ,Cruise ,Diamond ,Outbreak ,Retrospective cohort study ,engineering.material ,Asymptomatic ,engineering ,Medicine ,medicine.symptom ,business - Published
- 2020
28. Chemical compatibility of Cu-Ge alloy with container materials for latent heat storage system
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Selvan Bellan, Tatsuya Kodama, Nobuyuki Gokon, Chew Shun Jie, Tsuyoshi Hatamachi, and Hyun Seok Cho
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Latent heat storage ,Materials science ,business.industry ,Alloy ,Metallurgy ,engineering.material ,Solar energy ,visual_art ,Compatibility (mechanics) ,Container (abstract data type) ,Thermal ,visual_art.visual_art_medium ,engineering ,Ceramic ,Inert gas ,business - Abstract
Latent heat storage technology in CSP plant has been studied to enhance the dispatchability of solar energy in order to meet fluctuating electricity needs. A novel concept using metal alloys as latent heat storage material gives way to achieve this technology. In this paper, we analyzed the structural and thermal properties of Cu-Ge alloy to evaluate the potential of metallic PCM for high temperature TES application. Containment options for metallic PCM were explored and the materials are selected for long term operation. Compatibility tests of stainless steel, alumina and SiC ceramics under inert atmosphere were performed at high temperatures (800°C) for a duration of 1 month (720 h) in order to develop a suitable container material for thermal energy storage system.
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- 2020
29. Numerical analysis on solidification process of PCM in triplex-tube thermal energy storage system
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Hyun Seok Cho, Selvan Bellan, Nobuyuki Gokon, Koji Matsubara, Tatsuya Kodama, and Koya Hirai
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Materials science ,Fin ,Thermal conductivity ,business.industry ,Nuclear engineering ,Heat transfer ,Fossil fuel ,Thermal power station ,Thermal energy storage ,business ,Energy source ,Renewable energy - Abstract
Considerable attention is being paid in recent years to develop and improve alternative technologies to replace fossil fuels due to pollution problems and limited conventional energy sources. Solar thermal energy has been considering as one of the most attractive renewable sources to provide solution to the aforementioned problems. In recent years, latent thermal energy storage systems using phase change materials (PCMs) have been developed to aid energy supply and demand of solar thermal power plants. As one of the obstacles of these systems is the low thermal conductivity of PCMs, ceramic fin has been used in this study to enhance heat transfer rate between the PCM and heat transfer fluid. To assess the heat transfer characteristics of the triplex-tube thermal energy storage system with ceramic fin, a numerical model has been developed and the effect of fin for various Stefan numbers has been studied numerically. The heat transfer and solidification rates are significantly enhanced when connecting the fins between the inner and outer tubes.
- Published
- 2020
30. Thermochemical H2O splitting using LaSrMnCrO3 of perovskite oxides for solar hydrogen production
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Tatsuya Kodama, Naoki Ito, Hyun Seok Cho, Hiroki Sawaguri, Nobuyuki Gokon, Kazuki Hara, and Selvan Bellan
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chemistry.chemical_compound ,Materials science ,chemistry ,Hydrogen ,Thermal ,Thermal decomposition ,Analytical chemistry ,Oxide ,chemistry.chemical_element ,Sintering ,Oxygen ,Hydrogen production ,Perovskite (structure) - Abstract
A thermochemical two-step water-splitting cycle using perovskite oxide of La0.7Sr0.3Mn0.9Cr0.1O3 was examined for hydrogen production from water using concentrated solar radiation. The impact of the thermal reduction temperatures of 1000–1350 °C on oxygen/hydrogen productivity and repeatability was examined for hydrogen production at a water decomposition temperature of 1200 °C. The sample displayed relatively high evolution rates of oxygen at TR temperatures of 1350-1300°C, and showed similar rate at TR temperatures of 1000-1200 °C. After the sample was subjected to the TR step at temperatures of 1350-1300 °C, the obtained samples were superior hydrogen production rate to the others. On the other hand, the sample provided relatively good reactivities and repeatabilities for oxygen release and hydrogen production with a small production level without coagulation or sintering during the TR temperatures of 1000-1200 °C.
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- 2020
31. Acute eosinophilic pneumonia following aromatherapy with essential oil
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Tatsuya Kodama, Takanori Watanabe, Norikazu Mataki, Soichiro Kanoh, and Yoshiko Kichikawa
- Subjects
Pulmonary and Respiratory Medicine - Published
- 2022
32. Heat transfer analysis of 5kWth circulating fluidized bed reactor for solar gasification using concentrated Xe light radiation
- Author
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Koji Matsubara, Tatsuya Kodama, Nobuyuki Gokon, Hyun Seok Cho, and Selvan Bellan
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Materials science ,business.industry ,020209 energy ,Mechanical Engineering ,02 engineering and technology ,Building and Construction ,Mechanics ,Coke ,Computational fluid dynamics ,021001 nanoscience & nanotechnology ,Pollution ,Industrial and Manufacturing Engineering ,Discrete element method ,Volumetric flow rate ,General Energy ,Heat transfer ,Thermal ,0202 electrical engineering, electronic engineering, information engineering ,Fluidized bed combustion ,Electrical and Electronic Engineering ,0210 nano-technology ,business ,Civil and Structural Engineering ,Syngas - Abstract
A combined numerical and experimental investigation of hydrodynamics and heat transfer of internally circulating fluidized bed reactor for solar gasification of coal coke to produce syngas is reported. As the main objective of this study is to study the thermal performance of the reactor, chemically inert quartz particles have been used. A numerical model has been developed by the combined approach of computational fluid dynamics and discrete element method (CFD-DEM). The radiation transfer equation has been solved by the discrete ordinate (DO) model. The experimental data have been used for model validation. The thermal performance of the reactor and the spout-annulus flow have been predicted by the model and other hydrodynamic parameters such as internal solid volume fraction, velocity and temperature of the particles are analyzed as a function of superficial gas velocity (gas flow rate) at different initial conditions.
- Published
- 2018
33. Conjugate radiation-convection-conduction simulation of volumetric solar receivers with cut-back inlets
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Selvan Bellan, Mitsuho Nakakura, Tatsuya Kodama, and Koji Matsubara
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Coupling ,Pressure drop ,Convection ,geography ,geography.geographical_feature_category ,Materials science ,Renewable Energy, Sustainability and the Environment ,020209 energy ,02 engineering and technology ,Mechanics ,Radiation ,Inlet ,Thermal conduction ,Thermal ,cardiovascular system ,0202 electrical engineering, electronic engineering, information engineering ,General Materials Science ,Communication channel - Abstract
This study analyzes the effect of cut-back inlets on the conjugate heat transfer of honeycomb-channel solar receivers. Two-way coupling simulations are reported for a plane-surface inlet, and five kinds of cut-back inlet receivers. The receivers are based on a 1.9-mm × 1.9-mm square cell with a 1.0-mm wall thickness. The cut-back inlet receivers have different amounts of material removed from the walls at the channel inlets. Numerical simulations demonstrate that receivers with a 2.4-mm cut from the channel inlet increased the exit temperature by 20.0 K or more, and decreased the pressure drop relative to the plane-surface receiver. Therefore, the results indicate that the cut-back inlet receiver’s thermal, and hydrodynamic performance is better for industrial use than is the plane-surface receiver. This performance is then explained with detailed examinations of the individual heat-transfer processes in the model. These detailed comparisons indicate that the top cuts reduce shadow effects as light irradiates the channel walls, allowing more direct irradiation to reach the wall surface, thus improving the overall performance.
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- 2018
34. Numerical and experimental study on granular flow and heat transfer characteristics of directly-irradiated fluidized bed reactor for solar gasification
- Author
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Selvan Bellan, Tatsuya Kodama, Koji Matsubara, Nobuyuki Gokon, and Hyun Seok Cho
- Subjects
Materials science ,Renewable Energy, Sustainability and the Environment ,020209 energy ,Nuclear engineering ,Multiphase flow ,Energy Engineering and Power Technology ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Discrete element method ,Volumetric flow rate ,Physics::Fluid Dynamics ,Fuel Technology ,Fluidized bed ,Heat transfer ,Thermal ,0202 electrical engineering, electronic engineering, information engineering ,Particle size ,0210 nano-technology ,Porosity - Abstract
Solar gasification is one of the promising techniques to convert the carbonaceous materials to clean chemical fuels, which offers the advantages of being transportable as well as storable for extended period of time. In this study, thermal performance of a recently developed 5 kWth fluidized bed reactor for solar gasification has been investigated and reported. Discrete element method (DEM) has been used for modeling the granular flow, and computational fluid dynamics (CFD) method has been used for modeling the multiphase flow. To validate the developed model, experiments were preformed and compared with modeling results. Discrete ordinate radiation model has been used to solve the radiative transfer equation. The thermal performance of the reactor and particulate flow behavior have been predicted and the effect of particle size, particle size distribution and gas flow rate are analyzed. The results indicate that the performance of the bed increases when fluidizing the annulus region particles as the high porosity increases the diffusion rate of radiation throughout the bed.
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- 2018
35. No Therapeutic Effect of Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor Retreatment Despite T790M Disappearance: Case Report of 3 Cases
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Takeshi Kaneko, Masaharu Shinkai, Tatsuya Kodama, and Keisuke Watanabe
- Subjects
Pharmacology ,biology ,business.industry ,Pleural effusion ,medicine.drug_class ,Therapeutic effect ,General Medicine ,medicine.disease ,Tyrosine-kinase inhibitor ,respiratory tract diseases ,T790M ,Infectious Diseases ,Oncology ,Drug Discovery ,Cancer cell ,Cancer research ,biology.protein ,Medicine ,Pharmacology (medical) ,Clinical significance ,Epidermal growth factor receptor ,business ,Cytotoxicity - Abstract
Background: T790M is a major cause of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) resistance, but the clinical significance of T790M disappearance is unknown. Case Report: We report 3 cases of pulmonary adenocarcinoma which did not respond to EGFR-TKI retreatment even with T790M disappearance. T790M mutations were detected in the pleural effusions after the tumors had acquired EGFR-TKI resistance. T790M mutations disappeared from cancer cells in the pleural effusion after a break from the treatment drug and cytotoxic agent administration. However, no therapeutic effect was obtained despite EGFR-TKI reinitiation. Conclusions: Responsiveness to EGFR-TKI might not be restored in some cases, although the disappearance of T790M mutations is confirmed.
- Published
- 2018
36. A CFD-DEM study of hydrodynamics with heat transfer in a gas-solid fluidized bed reactor for solar thermal applications
- Author
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Hyun Seok Cho, Koji Matsubara, Selvan Bellan, Nobuyuki Gokon, and Tatsuya Kodama
- Subjects
Fluid Flow and Transfer Processes ,Superficial velocity ,Materials science ,business.industry ,020209 energy ,Mechanical Engineering ,Mixing (process engineering) ,Thermodynamics ,02 engineering and technology ,Mechanics ,Computational fluid dynamics ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Discrete element method ,Fluidized bed ,Heat transfer ,Thermal ,0202 electrical engineering, electronic engineering, information engineering ,0210 nano-technology ,business ,CFD-DEM - Abstract
The particles flow and heat transfer characteristics of a high temperature solar thermochemical fluidized bed reactor have been studied for solar beam-down concentrating systems. A numerical model has been developed by the combined approach of computational fluid dynamics (CFD) and discrete element method (DEM) collisional model since it is an effective approach for studying the gas-solid flow. The discrete ordinate model has been used to solve the radiation heat transfer. An experimental visualization of particles circulation pattern and mixing of two-tower fluidized bed system has been presented. A good agreement has been found between the experimental measurements and numerical predictions. The effect of gas superficial velocity, bed mass and inlet gas temperature on the flow pattern and temperature characteristics of the bed have been investigated. The results showed that the maximum and average temperature of the bed, depends on the top layer position and focal point of the concentrated radiation, decreased when increasing the total mass of the bed.
- Published
- 2018
37. Buoyancy-opposed volumetric solar receiver with beam-down optics irradiation
- Author
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Nobuyuki Gokon, Selvan Bellan, Tatsuya Kodama, K. Yoshida, Koji Matsubara, Hyun Seok Cho, and Mitsuho Nakakura
- Subjects
Materials science ,Buoyancy ,020209 energy ,02 engineering and technology ,engineering.material ,Industrial and Manufacturing Engineering ,Vertical orientation ,chemistry.chemical_compound ,Optics ,Thermal ,0202 electrical engineering, electronic engineering, information engineering ,Silicon carbide ,Irradiation ,Electrical and Electronic Engineering ,Civil and Structural Engineering ,Leakage (electronics) ,Computer simulation ,business.industry ,Mechanical Engineering ,Building and Construction ,021001 nanoscience & nanotechnology ,Pollution ,General Energy ,chemistry ,engineering ,Solar simulator ,0210 nano-technology ,business - Abstract
This paper describes a volumetric solar receiver that is vertically integrated with beam-down optics for condensed light irradiation. The heat-transfer performance of a silicon carbide honeycomb receiver was investigated using a 30-kW th solar simulator and numerical simulation. The experiments achieved an air temperature of 840 K at the receiver outlet by varying the operational parameters. Numerical simulations were performed for a vertical honeycomb block with beam-down irradiation and a horizontal honeycomb block with tower-type irradiation to elucidate the effects of buoyancy. Three blocks with different sizes were simulated for a variety of operational parameters. When the block was oriented vertically, the flow and temperature fields remained nearly symmetric in and near the receiver. In contrast, when it was oriented horizontally, the flow and temperature became asymmetric, with the hot spot moving toward the receiver's side wall and the stream in the receiver being reversed. The vertical orientation's robustness to buoyancy effects prevented any reduction in the receiver efficiency or outlet temperature and suppressed the thermal leakage.
- Published
- 2017
38. A rare case of atypical bone marrow sarcoidosis without pulmonary involvement in a Japanese woman
- Author
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Tatsuya Kodama, Maki Iwata, Hiroaki Takeo, and Norikazu Mataki
- Subjects
Pathology ,medicine.medical_specialty ,Sarcoidosis ,Case Report ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,Japan ,Bone Marrow ,Rare case ,Humans ,Medicine ,Granulomatous lesions ,Aged ,Hepatic sarcoidosis ,Granuloma ,medicine.diagnostic_test ,business.industry ,General Medicine ,medicine.disease ,medicine.anatomical_structure ,030228 respiratory system ,Granulomatous disease ,Glucocorticoid therapy ,Positron emission tomography ,Positron-Emission Tomography ,Female ,Bone marrow ,business - Abstract
Sarcoidosis is a systemic granulomatous disease of unknown origin characterised by the presence of non-caseating granulomatous lesions. Extrapulmonary sarcoidosis with bone marrow involvement is rare and even more so without pulmonary involvement. Here, we describe a case of 69-year-old woman diagnosed as having bone marrow and hepatic sarcoidosis without pulmonary involvement based on 18F-fluorodeoxyglucose positron emission tomography findings. She was successfully treated with systemic glucocorticoid therapy.
- Published
- 2021
39. Particle reactors for solar thermochemical processes
- Author
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Nobuyuki Gokon, Hyun Seok Cho, Tatsuya Kodama, and Selvan Bellan
- Subjects
Energy carrier ,Materials science ,Renewable Energy, Sustainability and the Environment ,020209 energy ,Nuclear engineering ,Thermal power station ,Thermodynamics ,02 engineering and technology ,Photovoltaic thermal hybrid solar collector ,Physics::Space Physics ,Thermal ,Concentrated solar power ,0202 electrical engineering, electronic engineering, information engineering ,Astrophysics::Solar and Stellar Astrophysics ,Water splitting ,General Materials Science ,Astrophysics::Earth and Planetary Astrophysics ,Physics::Chemical Physics ,Thermochemical cycle ,Syngas - Abstract
Utilization of solar thermal power for high temperature fuel production has the potential to significantly reduce the fossil fuel dependence of our current economy. Over the past two decades, remarkable progress has been made in the development of solar driven thermochemical reactors for the production of hydrogen and syngas as they are promising energy carriers for transportation, domestic and industrial applications. However, there are solar peculiarities in comparison to conventional thermochemical processes – high thermal flux density and frequent thermal transients because of the fluctuating insolation-, and conventional industrial thermochemical reactors are generally not suitable for solar driven reactors. Therefore, solar-specific modifications of reactor design are necessary to realize efficient solar driven thermochemical processes. In solar thermochemical reactors, the methods for solar-heating particulate solid feedstock to high temperatures can be broadly classified as solar “directly” and “indirectly” absorbing reactors. On solar thermochemical processes involving reacting solid particles at high temperatures, such as “solar two-step water splitting with metal oxides” and “solar gasification”, various types of solar directly and indirectly absorbing particle reactors have been developed. In this review, recent development of solar particle reactors for the above solar thermochemical processes is described.
- Published
- 2017
40. CFD-DEM investigation of particles circulation pattern of two-tower fluidized bed reactor for beam-down solar concentrating system
- Author
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Cho Hyun Cheok, Koji Matsubara, Selvan Bellan, Tatsuya Kodama, and Nobuyuki Gokon
- Subjects
Materials science ,Meteorology ,business.industry ,020209 energy ,General Chemical Engineering ,Flow (psychology) ,02 engineering and technology ,Mechanics ,Computational fluid dynamics ,Discrete element method ,Volumetric flow rate ,Physics::Fluid Dynamics ,Fluidized bed ,0202 electrical engineering, electronic engineering, information engineering ,Fluid dynamics ,Particle size ,business ,CFD-DEM - Abstract
In this study, a numerical model has been developed by the combined approach of computational fluid dynamics (CFD) and discrete element method (DEM) collisional model to study the particle-fluid flow of the fluidized bed reactor for solar beam-down concentrating system. The contact forces between the particles have been calculated by the spring-dashpot model, based on the soft-sphere method. An experimental visualization of particles circulation pattern and mixing of two-tower fluidized bed system has been presented. A good agreement has been found between the experimental measurements and numerical predictions. To investigate the influence of fluid flow rate and particle size on the flow pattern of the reactor, simulations have been performed for various conditions. The results indicate that the large size particles induce three-dimensional effects as they are accumulated at the central axis region. The average bed height of the left tower increased by 23.4% when increasing the flow rate about 70%.
- Published
- 2017
41. Effect of Coacervate of the Cationic Polymer and Surfactant on the Adhesion of Fragrance on the Hair
- Author
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Noriko Kanei, Tomoyoshi Harigai, and Tatsuya Kodama
- Subjects
Coacervate ,Chemical engineering ,Pulmonary surfactant ,Chemistry ,Cationic polymerization ,Adhesion - Published
- 2017
42. Japan Aims at Establishing a Hydrogen-Based Society—Can Solar Thermochemistry Contribute?
- Author
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Tatsuya Kodama
- Subjects
Hydrogen ,chemistry ,Renewable Energy, Sustainability and the Environment ,business.industry ,Thermochemistry ,Energy Engineering and Power Technology ,chemistry.chemical_element ,Solar energy ,business ,Engineering physics - Published
- 2019
43. Fe-doped manganese oxide redox material for thermochemical energy storage at high-temperatures
- Author
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Aoi Nishizawa, Tatsuya Kodama, Nobuyuki Gokon, Selvan Bellan, Takehiro Yawata, and Hyun Seok Cho
- Subjects
Thermogravimetric analysis ,Chemical substance ,Materials science ,chemistry.chemical_element ,Manganese ,Redox ,Energy storage ,law.invention ,Reaction rate ,Magazine ,Chemical engineering ,chemistry ,law ,Thermochemical cycle - Abstract
Fe-doped manganese oxides for solar thermochemical storage are studied using thermogravimetric reactor in a laboratory scale. The operation process of Fe-doped Mn2O3/Mn3O4 redox pair for two-step thermochemical cycle are optimized from the viewpoint of redox temperatures and thermochemical storage capacity, and the impact of operation temperatures on redox performances were experimentally evaluated. In addition, the thermochemical storage potentials of some Fe-X-doped manganese oxides are examined with regards to reaction rate, short-term cycling stability, storage capacity and redox temperatures.
- Published
- 2019
44. Heat transfer and fluid flow analysis of a fluidized bed reactor for beam-down optics
- Author
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Hyun Seok Cho, Koji Matsubara, Selvan Bellan, Tatsuya Kodama, and Nobuyuki Gokon
- Subjects
Materials science ,business.industry ,Fluidized bed ,Heat transfer ,Flow (psychology) ,Fluid dynamics ,Particle ,Mechanics ,Computational fluid dynamics ,business ,Discrete element method ,Beam (structure) - Abstract
A transient three dimensional numerical model of the heat transfer and fluid flow of a windowed fluidized bed reactor for solar thermochemical conversions is formulated and solved using discrete element method coupled to computational fluid dynamics. Radiation transfer equation is solved by discrete ordinate radiation model and the particle collision dynamics is solved by spring-dashpot model based on soft-sphere method. The instantaneous granular flow behavior of the irradiated bed is presented along with the incident radiation and particle size distribution. The results indicate that as time progresses the average velocity of the particle increases due to high temperature and bed expansion effect.
- Published
- 2019
45. Particles fluidized bed receiver/reactor with a beam-down solar concentrating optics: First performance test on two-step water splitting with ceria using a Miyazaki solar concentrating system
- Author
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Nobuyuki Gokon, Hyun Seok Cho, Selvan Bellan, Tatsuya Saito, Kouske Inoue, Shouta Watanabe, and Tatsuya Kodama
- Subjects
Chemical substance ,Materials science ,Nuclear engineering ,Two step ,Reflector (antenna) ,Fluidized bed ,Physics::Space Physics ,Astrophysics::Solar and Stellar Astrophysics ,Water splitting ,Particle ,Astrophysics::Earth and Planetary Astrophysics ,Physics::Chemical Physics ,Science, technology and society ,Beam (structure) - Abstract
A novel concept of a windowed, particle fluidized bed solar reactor was proposed by Niigata University for performing a two-step thermochemical water splitting cycle with redox metal-oxide particles. The solar reactor concept needs to be combined with a beam-down type solar concentrator. A new type of 100kWth beam-down solar concentrating system with a secondly elliptical reflector was built at the campus of University of Miyazaki, Japan. The solar reactor and the CPC were fabricated for demonstrating the concept of the windowed, particle fluidized bed solar reactor. The first performance tests of the solar reactor with pulverized ceria particles with 100 - 300 μm in diameter were carried out using the Miyazaki beam-down solar concentrating system.
- Published
- 2019
46. Cyclic thermal storage/discharge performances of a hypereutectic Cu-Si alloy under vacuum for solar thermochemical process
- Author
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Tatsuya Kodama, Nobuyuki Gokon, and Tomoya Yamaguchi
- Subjects
Materials science ,020209 energy ,Mechanical Engineering ,Alloy ,Metallurgy ,02 engineering and technology ,Building and Construction ,engineering.material ,021001 nanoscience & nanotechnology ,Solar fuel ,Thermal energy storage ,Pollution ,Phase-change material ,Industrial and Manufacturing Engineering ,Energy storage ,General Energy ,Differential scanning calorimetry ,0202 electrical engineering, electronic engineering, information engineering ,engineering ,Thermal stability ,Graphite ,Electrical and Electronic Engineering ,0210 nano-technology ,Civil and Structural Engineering - Abstract
A copper-silicon alloy (Cu-Si alloy) was examined and evaluated as a phase-change material (PCM) for thermal energy storage applications such as load shaving and peak load shifting when coupled to a solar thermochemical reactor, reformer, or gasifier for the production of solar fuel. The Cu-Si alloy was selected as a high-temperature PCM thermal storage medium alternative to molten carbonate salts, and the compatibility of this alloy with a graphite-carbon encapsulation material was experimentally examined. The cyclic thermal storage/discharge properties of the Cu-Si alloy as a latent-heat energy storage material were studied with respect to thermal cycles. A thermal stability test was performed on Cu-20 wt% Si, Cu-25 wt% Si, and Cu-30 wt% Si alloys placed in a graphite container under vacuum. The performances of the Cu-Si alloys with increasing and decreasing temperature were measured during the thermal storage (heat-charge) and cooling (heat-discharge) modes, respectively. The elemental distribution of each Cu-Si alloy after the cyclic reaction was evaluated using an electron probe microanalyzer (EPMA). The heat storage capacities before and after the cyclic reaction were evaluated using differential scanning calorimetry (DSC) and were compared to the thermal storage properties of the molten carbonate salt.
- Published
- 2016
47. Thermal charge/discharge performance of iron–germanium alloys as phase change materials for solar latent heat storage at high temperatures
- Author
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Chew Shun Jie, Nobuyuki Gokon, Selvan Bellan, Tatsuya Kodama, Yuya Nakano, and Hyun Seok Cho
- Subjects
Materials science ,Renewable Energy, Sustainability and the Environment ,020209 energy ,Alloy ,Energy Engineering and Power Technology ,chemistry.chemical_element ,Germanium ,02 engineering and technology ,engineering.material ,021001 nanoscience & nanotechnology ,Thermal energy storage ,Phase-change material ,chemistry ,Thermal ,0202 electrical engineering, electronic engineering, information engineering ,engineering ,Thermal stability ,Graphite ,Electrical and Electronic Engineering ,Composite material ,0210 nano-technology ,Eutectic system - Abstract
In this study, an iron–germanium alloy (Fe–Ge alloy) was examined as a phase change material at temperatures exceeding 800°C for thermal energy storage in solar thermal applications. The cyclic properties of the thermal charge/discharge of the Fe–Ge alloy were examined at various thermal cycles. A thermal reliability test was performed in the form of a multi-cyclic performance assessment to evaluate the short- and long-term thermal stability of this alloy. Eutectic and hypereutectic chemical compositions of the Fe–Ge alloy were placed in a graphite container under vacuum and an inert atmosphere. The Fe–Ge alloy was experimentally examined for its compatibility with the container material of graphite-carbon. The element distribution of each Fe–Ge alloy was examined via a cyclic performance test. The heat storage capacities were evaluated and compared with those of chloride molten salts. The Fe–Ge alloy exhibits significant potential as a latent heat storage material in next-generation solar thermal applications as it demonstrates various advantages, namely: a higher storage capacity than that of chloride molten salts, temperature followability to the phase diagram, a quick thermal response, satisfactory cyclic behavior of charge/discharge modes, a thermodynamically stable metallographic structure, and non-reactivity with capsulation materials of graphite carbon.
- Published
- 2020
48. Effects of Transition Metal Doping to Cerium-Oxides in Thermal Reduction Reaction
- Author
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Takaki Nishimura, Yuki Tsutsumi, Genta Sakane, Tomohiko Ishii, and Tatsuya Kodama
- Subjects
Cerium ,Materials science ,Transition metal ,chemistry ,Inorganic chemistry ,Thermal ,Doping ,chemistry.chemical_element ,Redox - Abstract
Considering our lives, novel energy production is so required, and many scientists have been investigated this problem from a lot of views. One of the ways for the new energy productions is the solar power thermochemical production by an oxidation-reduction reaction of the ceramics CeO2 (ceria). In this research, the ceria is used for obtaining an H2 gas in vapor reaction in high-temperature thermal equipment which has a heat production system consisting by focused sun light. Nowadays technology has been also developed to keep a human living, not to harm the Earth environment. From these points, it is realized that how important the H2 gas is for our lives, so we are trying to improve the thermochemical H2 gas production by means of a ceria as a catalyst. Our purpose in this study is, to point out what effects occur in doped ceria’s thermal reduction (TR) reaction by using DV-Xα method. Comparing the models between the pure ceria and the Mn doped ceria, we have realized the difference by the reaction. In this appearance, one of the considerations is a view from p-DOSs (partial-Density of States), in which there are different O-2p DOSs by different crystal structures. From this view, we considered that the ceria structure would become more stable to keep the stable cyclic thermal reaction in Mn doped ceria.
- Published
- 2020
49. Neuro-Sweet disease in a Japanese woman with Sjögren’s syndrome
- Author
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Tatsuya Kodama, Yuki Yamazaki, and Hiroaki Takeo
- Subjects
Adult ,medicine.medical_specialty ,Prednisolone ,Central nervous system ,Disease ,Diagnosis, Differential ,03 medical and health sciences ,0302 clinical medicine ,Adrenal Cortex Hormones ,Rare Disease ,Erythematous plaque ,medicine ,Humans ,Meningitis ,030203 arthritis & rheumatology ,business.industry ,Behcet Syndrome ,General Medicine ,Sweet Syndrome ,Dermatology ,Sjogren's Syndrome ,Treatment Outcome ,medicine.anatomical_structure ,Corticosteroid therapy ,Female ,Neutrophilic infiltration ,Sweet disease ,Sjogren s ,Complication ,business ,030217 neurology & neurosurgery - Abstract
Sweet disease (SD) is a multisystem inflammatory disorder characterised by fever, cutaneous erythematous plaques and aseptic neutrophilic infiltration of various organs. Neuro-Sweet disease (NSD) is a known rare central nervous system complication of SD. We describe a case of a 39-year-old Japanese woman who was diagnosed as NSD associated with Sjögren’s syndrome. She was successfully treated with systemic corticosteroid therapy.
- Published
- 2019
50. CFD-DEM investigation on flow and temperature distribution of ceria particles in a beam-down fluidized bed reactor
- Author
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Tatsuya Kodama, Hyun Seok Cho, Koji Matsubara, Nobuyuki Gokon, and Selvan Bellan
- Subjects
Physics::Fluid Dynamics ,Materials science ,Fluidized bed ,Heat transfer ,Flow (psychology) ,Mixing (process engineering) ,Mechanics ,Beam (structure) ,CFD-DEM ,Contact force - Abstract
In this research, heat transfer and hydrodynamics of a solar thermochemical fluidized bed reactor filled with ceria particles have been studied numerically and experimentally for beam-down solar concentrating system. A CFD-DEM model has been developed, in which the contact forces between the particles have been calculated by the spring-dashpot model, based on the soft-sphere method. An experimental visualization of particles circulation pattern and mixing of two-tower fluidized bed system has been presented. Simulation results have been compared with experimental data to validate the CFD-DEM model. Results indicate that the model can predict the particle-fluid flow of the two-tower fluidized bed reactor. Using this model, the key operating parameters can be optimized.
- Published
- 2018
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