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Improved performance of direct methanol fuel cells with the porous catalyst layer using highly-active nanofiber catalyst

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Carbon Resources Conversion 2018年第1期1卷 61-72页

作者： Yosuke Tsukagoshi Hirokazu Ishitobi Nobuyoshi nakagawa Department of Environmental Engineering Science Graduate School of Science and TechnologyGunma University1-5-1TenjinchoKiryuGunma 376-8515Japan Division of Environmental Engineering Science Gunma University1-5-1TenjinchoKiryuGunma 376-8515Japan

PtRu supported on TiO2-embedded carbon nanofibers(PtRu/TECNF),which was recently reported as a highly-active catalyst for methanol oxidation,was applied to a direct methanol fuel cell(DMFC),and the power generation performance was compared to that using the commercial PtRu/*** the comparison,the effect of the catalyst loading on the power density of the DMFC was investigated using PtRu(18 wt%)/*** DMFC power density showed a maximum at about a 1.5 mg cm2 PtRu loading that corresponds to about an 80 mm layer thickness.A catalyst layer thicker than this value reduced the power density probably due to the concentration *** PtRu content in the PtRu/TECNF was then increased to 30 wt%or more to reduce the layer thickness and to increase the power *** DMFC performance was compared to that of different anode catalysts at a 1 mg cm2 PtRu *** power density was maximized using the PtRu30 wt%/TECNF,which showed a 173 mW cm2 at 353 K and had 66 mm layer thick,that was 26%higher than that of commercial PtRu/*** current–voltage curve of the DMFC with the PtRu/TECNF suggested an improved mass transport overvoltage,but a little improvement in the activation one despite using the catalyst with about a 2 times higher activity compared to that of the commercial PtRu/*** was attributed to the lower Pt utilization of the nanofiber catalyst layer.

关键词： Direct methanol fuel cell Catalyst layer structure PtRu catalyst TiO2-embedded carbon nanofiber support Methanol oxidation reaction Power density Precious metal loading Concentration overvoltage

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Field survey of a sustainable sanitation system in a residential house

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Journal of Environmental Sciences 2006年第6期18卷 1088-1093页

作者： Naoko nakagawa Masahiro OTAKI Shinji MIURA Hironobu HAMASUNA Katsuyoshi ISHIZAKI Department of Human Environmental Sciences Ochanomizu University2-1-1OtsukaBunkyo-KuTokyo 112-8610Japan. City Maintenance Technical Research Center 2-9-23ShinjuShinjuku-KuTokyo 160-0023Japan Nagasaki Institute of Applied Science 536Abama-choNagasaki-shiNagasaki Pref.851-0123Japan Research Institute for a Sustainable Future Waseda University513 Tsurumaki-ChouWasedaShinjuku-KuTokyo 169-8050Japan

Sustainable sanitation is an approach for more ecological and sustainable water resources management. In this paper, we proposed one of the new integrated waste treatment systems： an ＂sustainable sanitation system＂ that includes separation of the black water from water system by a non-flushing toilet （bio-toilet）, and a gray water treatment based on a biological and ecological concept. Sustainable sanitation system also converts the domestic waste to soil conditioners and fertilizers, for farmland use. As one of the case studies, Environmentally Symbiotic Housing in which people actually live using the bio-toilet for the black water treatment and the household wastewater treatment facility for the gray water was introduced. The availability of this system was investigated by analyzing the sawdust used in the bio-toilet and the quality of the effluent in the household wastewater treatment facility. As the result, the water content of the sawdust did not exceed 60% in any of the sampling points and the BOD and COD of the effluent of the household wastewater treatment facility were below 10 and 20 mg/L respectively, due to the low loading. Compared to the pollution load on the water environment created by the conventional system, it was found that the effluent of the house has a lower load than the tertiary treatment and the volume of the water consumption is 75% of the conventional system.

关键词： bio-toilet pollution load sustainable sanitation system water consumption

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Photodimerization and photooxygenation of 9-vinylcarbazole catalyzed by titanium dioxide and magnesium perchlorate

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Chinese Chemical Letters 2010年第3期21卷 365-368页

作者： Hajime Maeda Mio Yamamoto Hideyuki nakagawa Kazuhiko Mizuno Division of Material Sciences Graduate School of Natural Science and TechnologyKanazawa University Department of Applied Chemistry Graduate School of EngineeringOsaka Prefecture University

Photoreaction of 9-vinylcarbazole in acetonitrile in the presence of titanium dioxide and a catalytic amount of magnesium perchlorate gave 3,6-di(9-carbazolyl)-1,2-dioxane as a photooxygenated product via photodimerization of *** photoreaction proceeds via an electron transfer mechanism,where magnesium perchlorate accelerated formation of the photo-oxygenated product.

关键词： Titanium dioxide Magnesium perchlorate 9-Vinylcarbazole Photooxygenation Photodimerization

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Factors influencing subjective symptoms in dry eye disease

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International Journal of Ophthalmology(English edition) 2018年第12期11卷 1926-1931页

作者： Hidenaga Kobashi Kazutaka Kamiya Takehiko Sambe Ryutaro nakagawa Department of Ophthalmology University of Kitasato School of MedicineKanagawa 160-8582Japan Schepens Eye Research Institute Massachusetts Eye and Ear InfirmaryDepartment of OphthalmologyHarvard Medical SchoolBoston 02115MassachusettsUSA Department of Pharmacology Showa University school of MedicineTokyo 152-8555Japan Brigham and Women's Hospital Harvard Medical School Boston 02115MassachusettsUSA Social Epidemiology and Chair Department of Social and Behavioral Sciences Harvard University T.H.Chan School of Public Health Boston 02115MassachusettsUSA Tama University Institute of Health Care solution Tokyo 206-0022Japan Department of Histology and Pathophysiology Tokyo medical university School of MedicineTokyo 160-0023Japan

AIM: To retrospectively investigate the association between dry eye symptoms and clinical or in vivo confocal microscopy parameters in patients with dry eye disease(DED), and to compare these parameters between eyes with DED and normal ***: This retrospective, cross-sectional, controlled study comprised 25 consecutive patients with non-Sj?gren dry eye disease and age-and sex-matched 25 healthy subjects. Each patient underwent a complete examination of the ocular surface in the following order: tear osmolarity measurements, InflammaDry test, tear break-up time, corneal fluorescein staining, Schirmer I test, subjective symptoms questionnaire using the dry eye-related qualityof-life score(DEQS), and in vivo confocal microscopy analysis of the central cornea. Beck depression inventory(BDI) as depressive scale and history of medications and smoking were also evaluated. Stepwise multiple regression analysis was used to assess the factors affecting the ***: In univariate analysis, DEQS was associated with tear break-up time(ρ=-0.48, P=0.01), oral medications, such as hypotensive drug(ρ=0.56, P=0.004) and antidepressant(ρ=0.57, P=0.003), and BDI(ρ=0.61, P=0.001) in patients with DED. In multiple regression analysis, explanatory variables relevant to the DEQS were the anti-depressant medications(P=0.04, partial regression coefficient B=21.04) and BDI(P=0.02, B=0.76, adjusted R2=0.54) in these patients. CONCLUSION: Our study shows a significant association between depression and dry eye symptoms. It suggests that dry eye symptoms associate with higher depressive symptoms and its medications, although our patients were not followed longitudinally.

关键词： dry eye disease in vivo confocal microscopy dry eye symptoms depression

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Aboveground biomass and seasonal patterns of aboveground net primary productivity in five bamboo species in northern Laos

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Journal of Plant Ecology 2020年第2期13卷 150-156页

作者： Singkone Xayalath Isao Hirota Shinsuke Tomita Michiko nakagawa Department of Forest and Environmental Resource Sciences Graduate School of Bioagricultural SciencesNagoya UniversityNagoya 464-8601Japan Department of Agricultural and Environmental Science Faculty of Applied Biological SciencesGifu UniversityGifu 501-1193Japan Asian Satellite Campuses Institute Nagoya UniversityNagoya 464-8601Japan

Aims Accurate estimates of bamboo biomass and net primary productivity(NPP)are required to evaluate the carbon sequestration potential of bamboo ***,relevant data that are important for climate change mitigation,have rarely been collected in regions outside of East Asia and *** on seasonal patterns of NPP and its components will enable the quantification of factors that influence the carbon balance in bamboo *** this study,we quantified the aboveground biomass(AGB)and aboveground NPP of five major bamboo species in northern Laos using monthly data collected over a 12-month *** All live culms in 10,2 m×2 m plots(for one monopodial bamboo species:Indosasa sinica)and 30 clumps per species(for four sympodial bamboo species:Bambusa tulda,Cephalostachyum virgatum,Dendrocalamus membranaceus and Gigantochloa sp.)were numbered and measured at breast *** set 10 or 20 litter traps per species to collect *** of dead and recruited culms and litterfall collection were performed once per month for 12 *** Findings The AGB was highest in ***(59.87 Mg ha^(-1))and lowest in ***(11.54 Mg ha^(-1)),and was mostly below the plausible global range for bamboos(32–256 Mg ha^(-1)).The sympatric distribution of multiple bamboo species at the study sites may have suppressed the AGB in four of the five studied *** aboveground NPP estimates were between 3.43 and 14.25 Mg ha^(-1) yr^(-1);those for ***(8.20 Mg ha^(-1) yr^(-1))and ***(14.25 Mg ha^(-1) yr^(-1))were comparable to mean global estimates for temperate evergreen forests(8.78 Mg ha^(-1) yr^(-1))and tropical moist forests(10.56 Mg ha^(-1) yr^(-1)).High culm recruitment rates(15.20–23.39%yr^(-1))were major contributors to aboveground NPP *** patterns of aboveground NPP were largely influenced by the phenology of the new *** the four sympodial bamboo species,new culms began to emerge following the onset of per

关键词： bamboo forest carbon sequestration culm dynamics litterfall northern Laos seasonality

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Estimation of debris flow discharge coefficient considering sediment concentration

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International Journal of Sediment Research 2019年第1期34卷 1-7页

作者： Namgyun Kim Hajime nakagawa Kenji Kawaike Hao Zhang Department of Civil and Earth Resource Engineering Kyoto University 2. Disaster Prevention Research CenterKyoto University Disaster Prevention Section Science Research CenterKochi University

A sabo dam has a purpose to block the path of debris flow. However, when overflow occurs, a sabo dam works as a weir, a vertical obstruction, where the fluid must flow over. Many empirical formulas and discharge coefficients for weirs relating flow depth to discharge have been proposed to calculate overflow discharges. However, only a few studies about overflow discharge coefficients are available in the case of debris flow. In this paper, experiments and numerical simulations were done to estimate debris flow discharge coefficients by considering the sediment concentration. In the numerical simulation, a complete overflow equation and a free overfall equation were implemented to calculate debris overflow discharges at a sabo dam. To determine the discharge coefficients for each equation, single factor regression analysis was used. Laboratory experiments were done to calibrate and to compare with the simulation. Study results showed that the discharge coefficients increase as the sediment concentration increases. This finding suggests debris flow discharge coefficients are derived to calculate the debris overflow discharges at a sabo dam.

关键词： Numerical simulation Debris flow Sabo dam Discharge coefficient

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Effects of hydraulic structures on river morphological processes

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International Journal of Sediment Research 2011年第3期26卷 283-303页

作者： Hiroshi TERAGUCHI Hajime nakagawa Kenji KAWAIKE Yasuyuki BABA Disaster Prevention Research Institute Kyoto UniversityJapan

Study of hydraulic structures such as groins and bandal-like structures can provide valuable information on their influences on morphological processes in natural *** structures usually used for bank protection and formation of deep navigation channel can locally create complex flow patterns,reduce flow velocities and also increase the flood *** of the previous studies are focused on structures like groins under non-submerged flow ***,the recent demand of nature friendly low cost and sustainable methods for river bank protection and channel formation leads to the necessity of study different type of structures like bandal-like *** this context, this study investigates the flow characteristics and sediment transport process influenced by bandal-like structures through laboratory *** experiments were carried out under live-bed scour condition with sediment supplied from the inlet for two submergence(non-submerged and submerged)*** experimental measurements contribute to better understand the mechanism of deposition/erosion process around different type of hydraulic *** performance of bandal-like structures considering the erosion around the structures,the deposition near the bank and the formation of deep main channel show promising results compared with conventional structures such as groins(impermeable and permeable ones).

关键词： Bandal-like structures Groins Sediment transport Submerged condition

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Influence of oxygen flow rate and compost addition on reduction of organic matter in aerated waste layer containing mainly incineration residue

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Journal of Environmental Sciences 2013年第1期25卷 53-58页

作者： Hiroshi Asakura Kei nakagawa Kazuto Endo Masato Yamada Yusaku Ono Yoshiro Ono Nagasaki University 1-14 Bunkyo-machi Nagasaki 852-8521Japan National Institute for Environmental Studies Onogawa 16-2TsukubaIbaraki 305-8506Japan Nippon Institute of Technology 4-1 GakuendaiMiyashiro-machiMinamisaitama-gunSaitama 345-8501Japan Kyoto Institute of Technology MatsugasakiSakyo-kuKyoto 606-8585Japan

Landfilling municipal solid waste incineration （MSWI） residue alkalizes the waste layer, causing a subsequent decrease in microbial activity and a delay in the decomposition of organic matter. In this study, efficiencies of neutralization of the leachate and organic matter decomposition in the waste layer in a column filled with MSWI residue using aeration and compost addition were evaluated. Total organic carbon （TOC） reduction in the waste layer is large at high oxygen flow rate （OFR）. To effectively accelerate TOC reduction in the waste layer to which compost was added, a high OFR exceeding that by natural ventilation was required. At day 65, the pH of the leachate when OFR was above 102 mol-O2/（day.m3） was lower than that when OFR was below 101 mol-Oz/（day.m3）. At the same OFR, the pH of waste sample was lower than that of waste sample with compost. Although leachate neutralization could be affected by compost addition, TOC reduction in the waste layer became rather small. It is possible that humic substances in compost prevent the decomposition of TOC in MSWI residue.

关键词： waste landfill aeration neutralization acceleration of stabilization

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Study on hydraulic characteristics of sabo dam with a flap structure for debris flow

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International Journal of Sediment Research 2017年第3期32卷 452-464页

作者： Yeonjoong Kim Hajime nakagawa Kenji Kawaike Hao Zhang Department of Civil and Earth Resources Engineering Disaster Prevention Research InstituteKyoto University Department of Civil and Earth Resources Engineering Director of Ujigawa Hydraulics Laboratory

The front part of the flow is very important and complex in the case of debris flow where there is an accumulation of large boulders. It is important to control or dampen the energy of the frontal part of a debris flow for the safety of the downstream area because the impact pressure of debris flow is much greater than that of clear fluid. The main objective of this study is to analyze the hydraulic characteristics of the proposed dam(i.e. closed-type dam with flap). The vertical pressure distribution of this type is compared with conventional dam types. In the experiments, the total pressure associated with major debris flows was recorded in real time by a system consisting of four dynamic pressure sensors installed on different types of dam. The results from experimental data clearly show that the dam with the flap has advantages of capturing the debris flow with large boulders and controls the total pressure by flow circulation due to presence of the flap structure compared to a closed-type dam without flap. Furthermore, the empirical coefficients of hydrodynamic and solid collision models were proposed and compared with available coefficients.

关键词： Debris flow Flap structure Empirical coefficient Total pressure

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Spatially Uniformizing of Very High Frequency Plasma for Large Scale Plasma Applications

Spatially Uniformizing of Very High Frequency Plasma for Lar...

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作者： nakagawa KENSHO 上海交通大学

学位级别：硕士

Spatially uniform and large scale VHF plasma has been required for several kinds of plasma application since VHF plasma enables us to male excellent quality film on surface modification of material for relatively short processing time compared with conventional radio frequency（RF, 13.56MHz）. However, VHF plasma is usually generated only on a part of the electrode due to the influence of standing wave since electrode length is almost comparable with wavelength of the VHF power supply and the electrode itself act as a distributed constant circuit. In this research, we have demonstrated the control of VHF plasma generation area by using two methods of the terminal impedance change and the phase modulation. Spatially uniform VHF plasma all over the electrode was successfully obtained by temporally sweeping the plasma generated partially.

关键词： VHF Plasma Large scale processing Phase modulation Terminal impedance

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