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Best mix of primary energy resources by renewable energy and fossil fuel with CCS in view of security,stability and sustainability——A vision on hydrogen supply chain by organic chemical hydride method

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Science China(Technological Sciences) 2010年第1期53卷 62-68页

作者： Junichi sakaguchi Research Institute of Technology Innovation & Strategy of Chiyoda Corporation 2-12-1TsurumichuoTsurumi-kuYokohama230-8601Japan

The best mix scenario by renewable energy and fossil fuel with or without CCS(Carbon Dioxide Capture and Storage) would be a solution to compromise Greenhouse Gases emission issue caused by carbon dioxide(CO2),and depletion of crude oil and natural gas *** fossil fuel with pre-combustion CCS means hydrogen manufacturing and also hydrogen can be produced via electrolysis with renewable energy,it is desirable to establish transportation and storage systems of hydrogen as a clean *** this paper a vision on Hydrogen Supply Chain by Organic Chemical Hydride(OCH) Method as well as comparison of CCS configuration are discussed.

关键词： pre-combustion CCS compressors and pumps for CCS Hydrogen Supply Chain Organic Chemical Hydride Method

Multi-point Optimization of Recirculation Flow Type Casing Treatment in Centrifugal Compressors

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Journal of Thermal Science 2016年第3期25卷 231-241页

作者： Min Thaw Tun Daisaku sakaguchi Nagasaki University 1-14 Bunkyo-machi 852-8521 Nagasaki Japan

High-pressure ratio and wide operating range are highly required for a turbocharger in diesel engines. A recirculation flow type casing treatment is effective for flow range enhancement of centrifugal compressors. Two ring grooves on a suction pipe and a shroud casing wall are connected by means of an annular passage and stable recirculation flow is formed at small flow rates from the downstream groove toward the upstream groove through the annular bypass. The shape of baseline recirculation flow type casing is modified and optimized by using a multi-point optimization code with a metamodel assisted evolutionary algorithm embedding a commercial CFD code CFX from ANSYS. The numerical optimization results give the optimized design of casing with improving adiabatic efficiency in wide operating flow rate range. Sensitivity analysis of design parameters as a function of efficiency has been performed. R is found that the optimized casing design provides optimized recirculation flow rate, in which an increment of entropy rise is minimized at grooves and passages of the rotating impeller.

关键词： Centrifugal Compressor Casing Treatment Multi-point Optimization Turbocharger

Markov decision processes associated with two threshold probability criteria

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控制理论与应用（英文版） 2013年第4期11卷 548-557页

作者： Masahiko sakaguchi Yoshio OHTSUBO Department of Mathematics Faculty of ScienceKochi University

This paper deals with Markov decision processes with a target set for nonpositive rewards. Two types of threshold probability criteria are discussed. The first criterion is a probability that a total reward is not greater than a given initial threshold value, and the second is a probability that the total reward is less than it. Our first （resp. second） optimizing problem is to minimize the first （resp. second） threshold probability. These problems suggest that the threshold value is a permissible level of the total reward to reach a goal （the target set）, that is, we would reach this set over the level, if possible. For the both problems, we show that 1） the optimal threshold probability is a unique solution to an optimality equation, 2） there exists an optimal deterministic stationary policy, and 3） a value iteration and a policy space iteration are given. In addition, we prove that the first （resp. second） optimal threshold probability is a monotone increasing and right （resp. left） continuous function of the initial threshold value and propose a method to obtain an optimal policy and the optimal threshold probability in the first problem by using them in the second problem.

关键词： Markov decision process Minimizing risk model Threshold probability Policy space iteration

Contribution of adult-born neurons to memory consolidation during rapid eye movement sleep

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Neural Regeneration Research 2022年第2期17卷 307-308页

作者： Akinobu Ohba Masanori sakaguchi International Institute for Integrative Sleep Medicine(WPI-IIIS) University of TsukubaTsukubaIbarakiJapan

Introduction: Memory consolidation stabilizes newly acquired memories by integrating them into pre-existing memory networks, which is thought to occurvia changes in synaptic strength. Sleep may influence memory consol... 详细信息

关键词： strength. sleep integrating

Velocity and Size of Droplets in Dense Region of Diesel Fuel Spray on Transient Needle Opening Condition

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Journal of Thermal Science 2005年第2期14卷 181-186页

作者： Hironobu UEKI Masahiro ISHIDA Daisaku sakaguchi Nagasaki University 1-14 Bunkyo-machi Nagasaki 852-8521JapanNagasaki University 1-14 Bunkyo-machiNagasaki 852-8521JapanNagasaki University 1-14 Bunkyo-machiNagasaki 852-8521Japan

In order to investigate the effect of transient needle opening on early stage of spray behavior, simultaneous measurements of velocity and size of droplet were conducted by a newly developed laser 2-focus velocimeter (L2F). The micro-scale probe of the L2F was consisted of two foci with a distance of 36μm. The tested nozzle had a single hole with a diameter of 0.2 mm. The measurements of injection pressure, needle lift, and crank angle were synchronized with the spray measurement by the L2F at the position 10 mm downstream from the nozzle exit. It has been clearly shown that the velocity and size of droplet increase with needle valve opening and that the probability density distribution of droplet size can be fitted to the Nukiyama-Tanasawa distribution under the transient needle opening condition.

关键词： droplet disintegration optical characterization laser 2-focus velocimeter.

Global Search of a Three-dimensional Low Solidity Circular Cascade Diffuser for Centrifugal Blowers by Meta-model Assisted Optimization

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Journal of Thermal Science 2018年第2期27卷 111-116页

作者： Daisaku sakaguchi Daiki Sakue Min Thaw Tun Nagasaki University 1-14 Bunkyo-machi Nagasaki 852-8521 Japan Yangon Technological University Insein Road East Gyogone Insein Township Yangon

A three-dimensional blade of a low solidity circular cascade diffuser in centrifugal blowers is designed by means of a multi-point optimization technique. The optimization aims at improving static pressure coefficient at a design point and at a small flow rate condition. Moreover, a clear definition of secondary flow expressed by positive radial velocity at hub side is taken into consideration in constraints. The number of design parameters for three-dimensional blade reaches to 10 in this study, such as a radial gap, a radial chord length and mean camber angle distribution of the LSD blade with five control points, control point between hub and shroud with two design freedom. Optimization results show clear Pareto front and selected optimum design shows good improvement of pressure rise in diffuser at small flow rate conditions. It is found that three-dimensional blade has advantage to stabilize the secondary flow effect with improving pressure recovery of the low solidity circular cascade diffuser.

关键词： Multi-point optimization Low solidity cascade diffuser Flow range enhancement

MICROMECHANICS OF THE DAMAGE-INDUCED CELLULAR MICROSTRUCTURE IN SINGLE CRYSTAL Ni-BASED SUPERALLOYS

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Acta Metallurgica Sinica(English Letters) 2004年第4期17卷 361-368页

作者： M.sakaguchi M.Okazaki Department of Mechanical Engineering Nagaoka University of Technology Tomioka Nagaoka 1603-1JapanDepartment of Mechanical Engineering Nagaoka University of Technology Tomioka Nagaoka 1603-1Japan

An analytical method to investigate the morphological evolution of the cellular mi-crostructure is explored and proposed. The method is essentially based on the Es-helby 's micromechanics theory, and it is extended so as to be applied for a material system containing inclusions with high volume fraction, by employing the average stress field approximation by Mori and Tanaka. The proposed method enables us to discuss a stable shape of precipitate in the material system, which must be influenced by many factors: e.g., volume fraction of precipitate; Young's modulus ratio and lattice misfit between matrix and precipitate; external stress field in multiaxial state; and heterogeneity of plastic strain between matrix and precipitate. A series of numerical calculations were summarized on stable shape maps. The application of the method to predict the γ' rafting in superalloys during creep showed that the heterogeneity of plastic strain between matrix and precipitates may play a significant role in the shape stability of the precipitate. Furthermore, it was shown that the method was successfully applied to estimate the morphology of the cellular microstructure formed in CMSX-4 single crystal Ni-based superalloy.

关键词： single crystal Ni-based superalloy cellular microstructure mi-cromechanics average field approximation stable shape of precipitate heterogeneity of plastic strain rafting

A User-friendly Living Cationic Polymerization: Degenerative Chaintransfer Polymerization of Vinyl Ethers by Simply Using Mixtures of Weak and Superstrong Protonic Acids

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Chinese Journal of Polymer Science 2019年第9期37卷 851-857页

作者： Mineto Uchiyama Masataka sakaguchi Kotaro Satoh Masami Kamigaito Department of Molecular and Macromolecular Chemistry Graduate School of Engineering Furo-cho Chikusa-ku Nagoya University

Mixtures of a weak protonic acid and a trace amount of superstrong protonic acid were used for the simple control of the cationic polymerization of vinyl ethers via a degenerative chain-transfer mechanism, in which the former acid works as a precursor of the chain transfer agent (CTA) or the dormant species and the latter works as a source of the cationic propagating species. The addition of mixtures of phosphoric acid dibutyl ester ((n=BuO)2PO2H) or 1 -octanethiol (n-C8H17SH) and a trace amount of trifluoromethanesulfonic acid (TfOH) to a solution of isobutyl vinyl ether (IBVE) at -78℃ resulted in polymers with controlled molecular weights, which were basically determined by the feed ratio of IBVE to the weak protonic acid, and narrow molecular weight distributions (Mw/Mn≈ 1.1). These results were almost the same as those obtained using their prepared adducts of IBVE as CT As in the presence of a trace amount of TfOH under similar conditions. Methanesulfonic acid (CH3SO3H), whose adduct of IBVE has not been isolated due to instability, was similarly used in conjunction with trace TfOH to result in controlled molecular weights but slightly broader MWDs (Mw/Mn = 1.2-1.8). These results indicate that the sulfoxonium ion is also an effective intermediate in the cationic DT polymerization in addition to the phosphonium and sulfonium intermediates derived from (n=BuO)2PO2H and C8H17SH, respectively. The simple living cationic polymerization was thus achieved by using a combination of a weak protonic acid and a trace amount of TfOH, which are both easily available, low cost, free from metal, and easy to handle, without need for preparation of the initiator.

关键词： Living cationic polymerization Degenerative chain transfer RAFT polymerization Metal free Vinyl ether

Degradation mechanism of tin phosphide as Na-ion battery negative electrode

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Green Energy & Environment 2019年第2期4卷 121-126页

作者： Hiroyuki Usui Yasuhiro Domi Ryota Yamagami Hiroki sakaguchi Department of Chemistry and Biotechnology Graduate School of Engineering Tottori University Center for Research on Green Sustainable Chemistry Tottori University Course of Chemistry and Biotechnology Department of Engineering Graduate School of Sustainability Science Tottori University

The degradation mechanism of an Sn_4P_3 electrode as Na-ion battery anode was investigated by using a transmission electron microscopic observation. At the first desodiation, we confirmed that Sn nanoparticles with 6 nm in size were dispersed in an amorphous-like P *** to this, we observed aggregated Sn particles with sizes exceeding 50 nm after the drastic capacity fading. The capacity fading mechanism was for the first time confirmed to be Sn aggregation. To improve the capacity decay, we carried out the two kinds of chargeàdischarge cycling tests under the reduced volume changes of Sn particles and P matrix by limiting desodiation reactions of Nae Sn and Na3P, respectively. The Sn_4P_3 electrode exhibited an excellent cyclability with the discharge capacity of 500 mA hg^(-1) for 420 cycles under the limited desodiation, whereas the capacity decay was accelerated under the limited sodiation. The results suggest that the Sn aggregation can be improved by the reduced volume change of the P matrix, and that it is very effective for improving anode performance of Sn_4P_3 electrode.

关键词： Tin phosphide(Sn4P3) Ionic liquid electrolyte Na-ion battery Negative electrode material Nanostructure