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Search Results: 1 - 10 of 224538 matches for " R. Ogawa "
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Syntheses of two deacetyl-thymosin β4 analogs and their anti-inflammatory effect on carrageenin-induced edema in the mouse paw
T. Abiko,R. Ogawa
Mediators of Inflammation , 2001, DOI: 10.1080/09629350120054563
Abstract: Two {Met(0)6}deacetyl-thymosin β4 analogs containing Phe(4F) or Tyr(Me) at position 12 were synthesized by the manual solid-phase method, and their anti-inflammatory effect on carrageenin-induced edema in the mouse paw was studied. Fluorination of the para-position of Phe12 resulted in a marked antiinflammatory effect on carrageenin-induced edema in the mouse paw compared with that of our synthetic {Met(0)6}deacetyl-thymosin β4, but the other analog, {Met(0)6, Tyr(Me)12}deacetyl-thymosin β4, showed a marked reduction of the anti-inflammatory effect.
Carbon Dioxide Capture and Utilization for Gas Engine  [PDF]
Takashi Ogawa
Energy and Power Engineering (EPE) , 2013, DOI: 10.4236/epe.2013.510064

Sodium glycinate absorption and ethylene carbonate synthesis from a mixture gas of ethylene oxide and carbon dioxide are evaluated as carbon dioxide capture and utilization system for gas engine flue gas. The energy requirement for CO2 capture is estimated at 3.3 GJ/tonne CO2. The ethylene carbonate synthesis utilizes more than 90% of the captured CO2 and supply 2.5 GJ/tonne CO2 of thermal energy, which is 76% of the energy requirement for CO2 capture. The thermal integration of the sodium glycinate absorption and the ethylene carbonate synthesis reduces the energy requirement for CO2 capture from 3.3 GJ/tonne CO2 to 0.8 GJ/tonne CO2. The energy requirement for the CO2 capture is supplied using the steam saturated at 0.78 MPa from the gas engine without its electric power reduction.

Urban Heat Island Assessment for a Tropical Urban Airshed in India  [PDF]
Manju Mohan, Yukihiro Kikegawa, B. R. Gurjar, Shweta Bhati, Anurag Kandya, Koichi Ogawa
Atmospheric and Climate Sciences (ACS) , 2012, DOI: 10.4236/acs.2012.22014
Abstract: There has been paucity of field campaigns in India in past few decades on the urban heat island intensities (UHI). Remote sensing observations provide useful information on urban heat island intensities and hotspots as supplement or proxy to in-situ surface based measurements. A case study has been undertaken to assess and compare the UHI and hotspots based on in-situ measurements and remote sensing observations as the later method can be used as a proxy in absence of in-situ measurements both spatially and temporally. Capital of India, megacity Delhi has grown by leaps and bounds during past 2 - 3 decades and strongly represents tropical climatic conditions where such studies and field campaigns are practically non-existent. Thus, a field campaign was undertaken during summer, 2008 named DELHI-I (Delhi Experiments to Learn Heat Island Intensity-I) in this megacity. Urban heat island effects were found to be most dominant in areas of dense built up infrastructure and at commercial centers. The heat island intensity (UHI) was observed to be higher in magnitude both during afternoon hours and night hours (maximum up to 8.3?C) similar to some recent studies. The three high ranking urban heat island locations in the city are within commercial and/or densely populated areas. The results of this field campaign when compared with MODIS-Terra data of land surface temperature revealed that UHI hotspots are comparable only during nighttime. During daytime, similar comparison was less satisfactory. Further, available relationship of maximum UHI with population data is applied for the current measurements and discussed in the context of maximum UHI of various other countries.
Plasma Fatty Acid Composition in Men over 50 in the USA and Japan  [PDF]
A. Takada, F. Shimizu, Y. Ishii, M. Ogawa, T. Takao, S. Koba, M. R. Carnethon, W. S. Harris
Food and Nutrition Sciences (FNS) , 2018, DOI: 10.4236/fns.2018.96054
Abstract: Background: Coronary heart disease (CHD) rates differ markedly between the US and Japan. Fatty acid profiles have been linked to risk for CHD. Few studies have compared the plasma fatty acid composition, including trans fatty acids, in Japanese and US subjects. Methods: Fasting blood samples were taken from healthy older (>age 50) American (n = 76) and Japanese (n = 44) men, and plasma levels of 23 fatty acids were analyzed by gas chromatography and expressed as a percent of total fatty acids. Results: As expected, plasma levels of long-chain ω3 fatty acids (docosahexaenoic and eicosapentaenoic acids, DHA and EPA) were higher in Japanese men and ω6 fatty acids (e.g., arachidonic acid, AA) were lower compared with American men. Plasma levels of the major industrially-produced trans fatty acids (IP-TFAs; elaidic and linoelaidic acids) were far higher in American men, and levels of the potentially cardioprotective, primarily ruminant-derived trans fatty acid palmitoelaidic acid (POA) were higher in Japanese. Plasma levels of saturated or monounsaturated fatty acids were also higher in the American men. Conclusion: There are multiple differences in plasma fatty acid profiles between American and Japanese older men. The higher levels of DHA and EPA, along with the lower levels of the IP-TFAs, are consistent with the markedly lower risk for coronary heart disease in Japan vs. the US.
Trends in age distribution of participants in a self-covered and a public expense-covered health check-up programs in Japan  [PDF]
Maki Ogawa, Atsushi Imai
Health (Health) , 2012, DOI: 10.4236/health.2012.49088
Abstract: Objective: In Japan, there are unique facilities (namely Ningen Dock) of health check-up, where asymptomatic participants undergo a medical examination at their own expense. The earlier occurrence of cervical cancer and the concern on screening prompted us compare to the age distribution in the self-covered system with that of free physical check-up programs at public expense. Methods: We analyzed medical records of Japanese women, who underwent gynecological examinations at self-covered expense and at public expense between for the periods 2002-2011 and 2005-2009, respectively, restricting examinee’s age group. Results: For self-covered system, approximately 80% of the overall examinee population was occupied with three age groups 30-39, 40-49 and 50-59. The participants was extremely fewer in the over 60 years age group accounting for 10%, compared to those for the public expense-covered system, the over 60 years age group being 25%. Participant under the age of 30 years seemed to increase in chronological order in both systems. Conclusion: The level of knowledge on sexually transmitted infections may contribute to screening promotion for the younger women, while the elderly over 60 years’ attitudes toward screening may be mainly related to social-economic status and/or public expense support.
The Relationship between Privatization and Regulation on Foreign Investment Policies  [PDF]
Lihua Han, Hikaru Ogawa
Theoretical Economics Letters (TEL) , 2015, DOI: 10.4236/tel.2015.51014
Abstract: Using a simple mixed oligopoly model, this paper examines the relationship between market-openings to foreign capital and privatization of a domestic public firm. Two types of market-openings are considered. First is that, given the number of the firms, the restriction on the share of foreign capital in each corporate joint venture is relaxed. Second is that, given the share of foreign capital in each corporate joint venture, the restriction on the number of the firms is relaxed. The analysis shows that the optimal level of privatization critically depends on the types of market openings to foreign capital. The optimal level of privatization declines as the share of foreign capital in each corporate joint venture increases. By contrast, the optimal level of privatization rises with an increase in the number of the firms operating in the market. The two different strategies for market-openings result in the opposite impacts on the welfare-maximizing government’s incentive for privatization.
Mechanism of Generation and Collapse of a Longitudinal Vortex System Induced around the Leading Edge of a Delta Wing  [PDF]
Shigeru Ogawa, Jumpei Takeda
Open Journal of Fluid Dynamics (OJFD) , 2015, DOI: 10.4236/ojfd.2015.53028
Abstract: The purpose of the paper is to clarify the mechanism of generation and collapse of a longitudinal vortex system induced around the leading edge of a delta wing. CFD captured well characteristics of flow structure of the vortex system. It is found that the vortex system has a cone-shaped configuration, and both rotational velocity and vorticity have their largest values at the tip of the vortex and reduce downstream along the vortical axis. This resulted in inducing the largest negative pressure at the tip of the delta wing surface. The collapse of the vortex system was also studied. The system can still remain until the tip angle of 110 degrees. However, between 110 degrees and 120 degrees, the system becomes unstable. Over 120 degrees, the characteristics of the vortex are considered to have converted from the longitudinal vortex to the transverse one.
Heat Transfer Enhancement by Vortex Generators for Compact Heat Exchanger of Automobiles  [PDF]
Shigeru Ogawa, Soma Usui
Open Journal of Fluid Dynamics (OJFD) , 2018, DOI: 10.4236/ojfd.2018.83020
Abstract: The paper describes the effects of heat transfer enhancement and gas-flow characteristics by wing-type-vortex-generators inside a rectangular gas-flow duct of a plate-fin structure exhaust gas recirculation (EGR) cooler used in a cooled-EGR system. The analyses are conducted using computational fluid dynamics (CFD). The numerical modelling is designed as a gas-flow rectangular duct of an EGR cooler using two fluids with high temperature gas and coolant water whose flow directions are opposite. The gas-flow duct used to separate two fluids is assembled with a stainless steel material. The inlet temperature and velocity of gas flowed inside gas-flow duct are 400°C and 30 m/s, respectively. Coolant water is flowed into two ducts on both a top and a bottom surface of the gas-flow duct, and the inlet temperature and velocity is 80°C and 0.6 m/s, respectively. Wing-type-vortex-generators are designed to achieve good cooling performance and low pressure drop and positioned at the center of the gas-flow duct with angle of inclination from 30 to 150 degrees at every 15 degrees. The temperature distributions and velocity vectors gained from numerical results were compared, and discussed. As a result, it is found that the vortices guided in the proximity of heat transfer surfaces play an important role in the heat transfer enhancement and low pressure drop. The collapse of the vortices is caused by complicated flow induced in the corner constituted by two surfaces inside gas-flow duct.
Performance Improvement by Control of Wingtip Vortices for Vertical Axis Type Wind Turbine  [PDF]
Shigeru Ogawa, Yusuke Kimura
Open Journal of Fluid Dynamics (OJFD) , 2018, DOI: 10.4236/ojfd.2018.83021
Abstract: The present paper describes control of wingtip vortices generated by vertical type wind turbine. The wind turbine consists of three circular cylinders. Each cylinder rotates on its own vertical axis and moves in orbit. It is known that wingtip vortices give rise to decrease of power generation performance as well as aerodynamic noise. Therefore, the goal of the study is to control wingtip vortices and to improve power generation performance. Numerical study was conducted for 14 models to find out control factors to suppress wingtip vortices. Numerical simulation visualized wingtips by streamlines as well as pressure distribution on the circular cylinder for evaluating Magnus effect. As a result, the following findings were obtained: 1) Installation of fully covered protection plates at both ends of the circular cylinder blades is greatly effective to suppress the wingtip vortices. 2) Curved wings attached to each cylinder are more effective to enhance power generation efficiency than flat ones, due to great increase in Magnus effect caused by large pressure difference on both sides of the curved wing. The power efficiency of the optimized model was improved up to 2.8%, which means 11 times that of the original model.
Reconstruction of the biogeochemistry and ecology of photoautotrophs based on the nitrogen and carbon isotopic compositions of vanadyl porphyrins from Miocene siliceous sediments
Y. Kashiyama,N. O. Ogawa,M. Shiro,R. Tada
Biogeosciences Discussions , 2008,
Abstract: We determined both the nitrogen and carbon isotopic compositions of various vanadyl alkylporphyrins isolated from siliceous marine sediments of the Onnagawa Formation (middle Miocene, northeastern Japan) to investigate the biogeochemistry and ecology of photoautotrophs living in the paleo-ocean. The distinctive isotopic signals support the interpretations of previous works that the origin of 17-nor-deoxophylloerythroetioporphyrin (DPEP) is chlorophylls c, whereas 8-nor-DPEP may have originated from chlorophylls a2 or b2 or bacteriochlorophyll a. Although DPEP and cycloheptanoDPEP are presumably derived from common precursory pigments, their isotopic compositions differed in the present study, suggesting that the latter represents a specific population within the photoautotrophic community. Based on the δ 15N values of DPEP ( 6.9 to 3.6‰ n=7), the average δ15N value for the entire photoautotrophic community is estimated to be 2 to +1‰, considering the empirical isotopic relationships that the tetrapyrrole nuclei of chloropigments are depleted in 15N by ~4.8‰ and enriched in ;13C by ~1.8‰ relative to the whole cells. This finding suggests that nitrogen utilized in the primary production was supplied mainly through N2-fixation by diazotrophic cyanobacteria. Based on the δ13C values of DPEP (–17.9 to 15.6‰ n=7), we estimated isotopic fractionation associated with photosynthetic carbon fixation to be 8–14‰. This range suggests the importance of β-carboxylation and/or active transport of the carbon substrate, indicating in turn the substantial contribution of diazotrophic cyanobacteria to primary production. Based on the δ15N values of 17-nor-DPEP ( 7.4 to 2.4‰ n=7), the δ15N range of chlorophylls c-producing algae was estimated to be 3 to +3‰. This relative depletion in ;15N suggests that these algae mainly utilized nitrogen regenerated from diazotrophic cyanobacteria. Given that diatoms are likely to have constituted the chlorophylls c-producing algae within the biogenic-silica-rich Onnagawa Formation, cyanobacteria-hosting diatoms may have been important contributors to primary production.
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