Numerical Analysis of Flow in Radial Turbine (Effects of Nozzle Vane Angle on Internal Flow)

OTSUKA, Kenta,KOMATSU, Tomoya,TSUJITA, Hoshio,YAMAGUCHI, Satoshi,YAMAGATA, Akihiro Korean Society for Fluid machinery 2016 International journal of fluid machinery and syste Vol.9 No.2

Variable Geometry System (VGS) is widely applied to the nozzle vane for the radial inflow turbine constituting automotive turbochargers for the purpose of optimizing the power output at each operating condition. In order to improve the performance of radial turbines with VGS, it is necessary to clarify the influences of the setting angle of nozzle vane on the internal flow of radial turbine. However, the experimental measurements are considered to be difficult for the flow in radial turbines because of the small size and the high rotational speed. In the present study, the numerical calculations were carried out for the flow in the radial turbine at three operating conditions by applying the corresponding nozzle vane exit angles, which were set up in the experimental study, as the inlet boundary condition. The numerical results revealed the characteristic flow behaviors at each operating condition.

CHEMICAL ABUNDANCES AND DUST IN THE HALO PLANETARY NEBULA K648 IN M15: ITS ORIGIN AND EVOLUTION BASED ON AN ANALYSIS OF MULTIWAVELENGTH DATA

Otsuka, Masaaki,Hyung, Siek,Tajitsu, Akito IOP Publishing 2015 The Astrophysical journal Supplement series Vol.217 No.2

<P>We report on an investigation of the extremely metal-poor and C-rich planetary nebula (PN) K648 in M15 using the UV to far-infrared data obtained using Subaru, the Hubble Space Telescope, the Far Ultraviolet Spectroscopic Explorer, Spitzer, and Herschel. We determined the nebular abundances of 10 elements. The enhancement of F ([F/H] = +0.96) is comparable to that of the halo PN BoBn1. The central stellar abundances of seven elements are determined. The stellar C/O ratio is similar to the nebular C/O ratios from recombination lines and from collisionally excited lines (CELs) within error, and the stellar Ne/O ratio is also close to the nebular CEL Ne/O ratio. We found evidence of carbonaceous dust grains and molecules including Class B 6-9 and 11.3 mu m polycyclic aromatic hydrocarbons and the broad 11 mu m feature. The profiles of these bands are similar to those of the C-rich halo PNe H4-1 and BoBn1. Based on the theoretical model, we determined the physical conditions of the gas and dust and their masses, i.e., 0.048 and 4.95 X 10(-7) M-circle dot, respectively. The observed chemical abundances and gas mass are in good agreement with an asymptotic giant branch nucleosynthesis model prediction for stars with an initial 1.25 M-circle dot plus a 2.0 X 10(-3) M-circle dot partial mixing zone (PMZ) and stars with an initial mass of 1.5 M-circle dot without a PMZ. The core mass of the central star is approximately 0.61-0.63 M-circle dot. K648 is therefore likely to have evolved from a progenitor that experienced coalescence or tidal disruption during the early stages of evolution, and became a similar to 1.25-1.5 M-circle dot blue straggler.</P>

DUST AND CHEMICAL ABUNDANCES OF THE SAGITTARIUS DWARF GALAXY PLANETARY NEBULA Hen2-436

Otsuka, Masaaki,Meixner, Margaret,Riebel, David,Hyung, Siek,Tajitsu, Akito,Izumiura, Hideyuki IOP Publishing 2011 The Astrophysical journal Vol.729 No.1

<P>We have estimated elemental abundances of the planetary nebula (PN) Hen2-436 in the Sagittarius (Sgr) spheroidal dwarf galaxy using ESO/VLT FORS2, Magellan/MMIRS, and Spitzer/IRS spectra. We have detected candidates of fluorine [F II] lambda 4790, krypton [Kr III] lambda 6826, and phosphorus [P II] lambda 7875 lines and successfully estimated the abundances of these elements ([F/H] = +1.23, [Kr/H] = +0.26, [P/H] = +0.26) for the first time. These elements are known to be synthesized by the neutron capture process in the He-rich intershell during the thermally pulsing asymptotic giant branch (AGB) phase. We present a relation between C, F, P, and Kr abundances among PNe and C-rich stars. The detections of these elements in Hen2-436 support the idea that F, P, Kr together with C are synthesized in the same layer and brought to the surface by the third dredge-up. We have detected N II and O II optical recombination lines (ORLs) and derived the N2+ and O2+ abundances. The discrepancy between the abundance derived from the oxygen ORL and that derived from the collisionally excited line is > 1 dex. To investigate the status of the central star of the PN, nebula condition, and dust properties, we construct a theoretical spectral energy distribution (SED) model to match the observed SED with Cloudy. By comparing the derived luminosity and temperature of the central star with theoretical evolutionary tracks, we conclude that the initial mass of the progenitor is likely to be similar to 1.5-2.0M(circle dot) and the age is similar to 3000 yr after the AGB phase. The observed elemental abundances of Hen2-436 can be explained by a theoretical nucleosynthesis model with a star of initial mass 2.25 M-circle dot, Z = 0.008, and LMC compositions. We have estimated the dust mass to be 2.9x10(-4) M-circle dot (amorphous carbon only) or 4.0x10(-4) M-circle dot (amorphous carbon and polycyclic aromatic hydrocarbon). Based on the assumption that most of the observed dust is formed during the last two thermal pulses and the dust-to-gas mass ratio is 5.58 x 10(-3), the dust mass-loss rate and the total mass-loss rate are < 3.1x10(-8) M-circle dot yr(-1) and < 5.5x10(-6) M-circle dot yr(-1), respectively. Our estimated dust mass-loss rate is comparable to a Sgr dwarf galaxy AGB star with similar metallicity and luminosity.</P>

Soft-magnetic Characteristics of Co-based Amorphous Powder Produced by Spinning Water Atomization Process (SWAP)

Otsuka I.,Wada K.,Watanabe A.,Kadomura T.,Yagi M. 한국분말야금학회 2006 한국분말야금학회 학술대회논문집 Vol.2006 No.1

Co-based amorphous powder was produced by a new atomization process “Spinning Water Atomization Process (SWAP)”, having rapid super-cooling rate. The composition of the alloys was ((Co0.95Fe0.05)1-xCrx)75Si15B10 (x=0, 0.025, 0.05, 0.075). The powders became the amorphous state even if particle size was up to about 500 μm. The coercive force of powders was about 0.35 - 0.7 Oe. Furthermore, Co-based amorphous powder cores with glass binders were made by cold-pressing and sintering methods. The initial permeability of the core in the frequency range up to 100 kHz was about 110, and the core loss at 100 kHz for Bm = 0.1 T was 350 kW/m3.

Establishment of Process of Manufacture of Ti-6Al-4V Alloy Sintering Body by MIM

Otsuka A.,Suzuki K.,Achikita M. 한국분말야금학회 2006 한국분말야금학회 학술대회논문집 Vol.2006 No.1

Ti-6Al-4V has low specific gravity, high corrosion resistance and superior mechanical properties but it is very difficult to control oxygen content in MIM process. It is necessary to use powders with coarse particle size to decrease oxygen content of powders, so feedstocks with poor fluidity and sintered bodies with lower density are obtained in such cases. Fine titanium hydride-dehydride powders were blended with atomized powders to accomplish higher fluidity and sintered density. Sintered bodies had higher sintered density and mechanical properties equivalent to those of wrought materials by controlling oxygen content less than 0.35mass%.

THE ORIGIN AND EVOLUTION OF THE HALO PN BoBn 1: FROM A VIEWPOINT OF CHEMICAL ABUNDANCES BASED ON MULTIWAVELENGTH SPECTRA

Otsuka, Masaaki,Tajitsu, Akito,Hyung, Siek,Izumiura, Hideyuki IOP Publishing 2010 The Astrophysical journal Vol.723 No.1

Real-world experience of dupilumab

( Atsushi Otsuka ) 대한피부과학회 2019 대한피부과학회 학술발표대회집 Vol.71 No.2

A New Potent Angiogenesis Inhibitor, FR-118487

TAKANAO, OTSUKA,OHKAWA, TAKEHIKO,SHIBATA, TOSHIHIRO,OKU, TERUO,OKUHARA, MASAKUNI,TERANO, HIROSHI,MASANOBU KOHSAKA,IMANAKA, HIROSHI 한국미생물 · 생명공학회 1991 Journal of microbiology and biotechnology Vol.1 No.3

A new angiogenesis inhibitor, FR-118487 was obtained by chemical modification of FR-111142 which was isolated from the fermentation products of Scolecobasidium arenarium F-2015. The antiangiogenic activity of FR-118487 was compared with that of the parent compound, FR-111142. In the endothelial cell proliferation test in vitro and the anglogenesis in the chick embryo chorioallantoic membrane assay, FR-118487 had about 5∼10 times stronger antiangiogenic activities than FR-111142. In addition, FR-118487 inhibited the angiogenesis in the rabbit corneal assay and suppressed the solid tumor growth in mice. These findings showed that FR-118487 would be a unique antiangiogenic agent with promising antitumor activity.

「留學生30万人計畵」に基づく 外國人留學生に對する支援體制の構築 -高知大學の事例を中心に-

( Kaoru Otsuka ),( Cuifang Lin ) 한국일어교육학회 2012 일본어교육연구 Vol.0 No.22

本稿は、「留學生30万人計畵」實現に向けての地方大學における留學生の受入れから卒業後の進路までを見 据えた體系的な體係策について「高知大學留學生に關する調査」の結果に基づき提言したものである。①敎員 の留學生受入れ體制の構築、②海外の協定校へのリクル一ト活動の推進、③大學獨自の入試制度の導入、④魅 力あるカリキュラムの導入、⑤民間住宅の借り上げ廣充等宿舍の充實、⑥大學獨自の奬學金の繼續·廣充、⑦留 學生に一定樺を確保する授業料免除制度の改善、⑧交換留學生廣充のための日本語補講授業の單位化、⑨留學 生の就職支援體制の構築、⑩卒業後のフォロ一アップ體制の充實等の問題点において地方大學ならではの提 言を行った。 Based on the results of the Investigation Concerning the International Students of Kochi University, this article puts forward proposals about the systematic measures relating to issues from international student recruitment to career paths after graduation at the local universities according to the 300,000 International Student Recruitment Plan. Ten main points are proposed as follows: 1. Construction of teachers` system for the recruitment of international students and sharing of information within a whole university. 2. Promotion of recruitment activities like briefing sessions at the overseas agreement-signed universities. 3. Promotion of admissions to universities and introduction of their own entrance exam system. 4. Introduction of attractive curriculums like acquisition of double degrees. 5. Expansion of leased private housing and building more International Houses. 6. Reinforcement of scholarship system by their own universities. 7. Improvement of tuition exemption system that secures a certain number of international students. 8. Acquisition of credits by taking Japanese supplementary classes for increasing the number of exchange students. 9. Construction of employment support system for international students through society-academia collaboration. 10. Reinforcement of follow-up system after graduation in overseas branch offices.

Design of Mechanochromic Polymers Based on Dynamic Covalent Chemistry

Hideyuki Otsuka 한국고분자학회 2019 한국고분자학회 학술대회 연구논문 초록집 Vol.44 No.2