著者
奥村 幸彦 渡部 弘達 岡崎 健
出版者
一般社団法人 日本機械学会
雑誌
日本機械学会論文集B編 (ISSN:18848346)
巻号頁・発行日
vol.79, no.799, pp.465-476, 2013 (Released:2013-03-25)
参考文献数
31
被引用文献数
1 1

The purpose of this study is to clarify the fundamental and general features of N2O formation during the combustion of pulverized biomass under low temperature. First, the effect of various important factors, i.e., combustion temperature, volatilization process (i.e., either slow or rapid dispersion), and nitrogen content in biomass on N2O formation were investigated by numerical analysis. The analysis of the effect of combustion temperature on the formation of nitrous oxide showed that N2O emission level increases with the decrease in combustion temperature, and both N2O and NO levels are strongly dependent on the combustion temperature. In other words, there is a trade-off relationship between the formation of NO and that of N2O. The analysis of the effect of the slow/rapid volatilization process on the formation of nitrous oxide showed that the conversion ratio of biomass-N to N2O increases with the decrease in the dispersion of volatile matter per unit time; it means that biomass-N is effectively converted to N2O during slow volatilization. Further, the gasification reactions among CO2, O2, and C occur simultaneously on the surface of biomass particles during combustion. With respect to the effect of nitrogen content in biomass, the N2O emission level increases with the increase in N-content of the biomass, while the NO emission level remains constant during low-temperature combustion.
著者
奥村 幸彦 増野 淳 南田 智昭 須山 聡 岡田 隆
出版者
一般社団法人 電子情報通信学会
雑誌
電子情報通信学会 通信ソサイエティマガジン (ISSN:21860661)
巻号頁・発行日
vol.14, no.3, pp.186-199, 2020 (Released:2020-12-01)
参考文献数
14

第5 世代移動通信システム(5G)の特長を生かした医療分野の新しいソリューション実現に向け,NTTドコモが推進してきた5G を医師対医師の遠隔診療に活用する事例の検討及びその実証試験の実施結果を紹介する.2017 〜 2019 年度に総務省の5G 総合実証試験として医療機関を含むパートナーとともに推進した実証試験は,地域医療・救急医療の充実に向け,5G の超高速通信を生かして複数の医療機器から出力される高精細診断映像とテレビ会議の映像をリアルタイムに同時伝送する試験用のシステムを構築し,それらを用いて複数の診療科を対象とした試験・評価を通して5G を活用する遠隔診療システムの有効性を確認した.地域医療分野における実証試験では,和歌山県において,山間部診療所での遠隔診療,遠隔訪問診療,遠隔教育,遠隔移動診療の各事例について,また,救急医療分野における実証試験では,群馬県前橋市において,救急搬送の高度化ソリューションとして,3 または4 拠点間で救急搬送情報を共有する形式の遠隔診療について,それぞれ実験用5G 無線通信装置を用いた試験を行い,各試験に参画した医療従事者及び関係者から多角的な評価結果を得た.
著者
奥村 幸彦 岡崎 健
出版者
一般社団法人日本機械学会
雑誌
日本機械学會論文集. B編 (ISSN:03875016)
巻号頁・発行日
vol.73, no.731, pp.1434-1441, 2007-07-25
被引用文献数
3

This paper reports on the pyrolysis and CO_2-gasification of various biomass materials in a pressurized thermobalance. In particular, the primary yields of total volatiles, tar and non-condensable gases, together with the composition of non-condensable gases, are measured as a function of temperature at 1 atm and 10.8 ata. The use of a high-intensity infrared heating source, in conjunction with a non-absorbing carrier gas (viz. argon), is reported to reduce the significance of secondary gas-phase pyrolysis reactions. Linear trends with atomic H/C ratio are observed in the tar yield, total volatile yield and CH_4 yield during pyrolysis. The gasification kinetics of biomass chars (pyrolysed to 700℃ at a medium heating rate) have also been measured by measuring the rate of weight loss during reaction with CO_2 as a function of temperature. First-order kinetic rate constants are then determined by fitting the weight loss data using a random pore model. The results indicate that the reactivity of the biomass materials is intermediate between lignin and cellulose and that they are much more reactive than a black coal char.
著者
奥村 幸彦 金内 健 岡崎 健
出版者
一般社団法人日本機械学会
雑誌
日本機械学會論文集. B編 (ISSN:03875016)
巻号頁・発行日
vol.71, no.702, pp.702-710, 2005-02-25
被引用文献数
1

The coal-pyrolysis experiment under elevated pressure conditions using a pressurized ther-mobalance has been carried out to clarify the mechanisms and the processes at conditions changing from normal pressure to higher pressure (10.6 ata) and from slow (0.1 K/s) to rapid heating rate (20 K/s). Simultaneously, a new pyrolysis model which can describe a pressure effect on the evolution behavior has been developed based on the FLASHCHAIN^[○!R] model including a quantitative estimation of the volatilized gases and released tar vapor. From the experiment, the tar vapor formation is suppressed and the yields of CH_4 gas shows increasing behavior at higher pressure conditions. Because the mole fraction of tar vapor decreased with the increase of the pressure by Raoult's law, and the recombination reactions of remaining metaplast (precursor of tar) within the coal are activated, resulting in more chars and more gas yields (CH_4, CO_2). At rapid heating rate conditions, the conversion from the metaplast to the volatile matter would be more active, because the reaction temperature range for thermal pyrolysis shifts to higher range with increase of heating rate. It was found that the rapid heating rate affects the molecular structure of the coal substantially.
著者
土肥 智弘 奥村 幸彦 安達 文幸
出版者
一般社団法人電子情報通信学会
雑誌
電子情報通信学会技術研究報告. RCS, 無線通信システム
巻号頁・発行日
vol.97, no.31, pp.17-24, 1997-04-25
被引用文献数
31

広帯域コヒーレントDS-CDMA(W-CDMAの野外伝送実験を行い、チップレート(拡散帯域幅)と送信電力の関係、チップレートと誤り率特性の関係を明らかにした。チップレートの高速化によりマルチパスの分解能力が向上し、RAKE受信後の受信電力の変動幅が小さくなり、低レベルへの落ち込み確率が減少するため、チップレートが高速になるほど送信電力は低減されることを実証した。また、アンテナダイバーシチ受信により誤り率特性が約3dB改善されることも明らかにした。