Papers by Keyword: Hydrogen Gas

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Authors: Kazushi Yamanaka
Abstract: Detection of hydrogen gas is a crucial task for establishing safety and reliability of fuel cells, a key technology for the environment and our society. However, hydrogen is difficult to detect and various hydrogen sensors have many drawbacks. Here we report a novel hydrogen gas sensor, the ball surface acoustic wave (SAW) sensor, using Pd or PdNi sensitive film. The ball SAW sensor is based on a novel phenomenon, diffraction-free propagation of collimated beam along an equator of sphere. The resultant ultra-multiple roundtrips of SAW makes it possible to achieve highest sensitivity among SAW sensors. Moreover, it enables to use a very thin sensitive film, and consequently the shortest response time (2s) was realized. In terms of the sensing range, it has the widest range of 10 ppm to 100 % among any hydrogen sensors including FET or resistivity sensors. The ball SAW sensor can be applied not only to hydrogen but also to any gasses and possibly to liquids.
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Authors: Zhi Gen Zhao, Ji Wen Wu
Abstract: Methane in coal mine gas is the research focus about the prevention of gas hazard and the development and utilization of coal bed methane. There have been more researches on heavy hydrocarbon in coal mine gas and a consensus has been formed about heavy hydrocarbon. Compared with methane and heavy hydrocarbon in coal mine gas, the research on hydrogen in coal mine gas is few and just unfolding. In this paper, 1097 gas samples are prepared based on 1097 coal samples. And, the hydrogen in gas samples is tested by Gas Chromatography. The research reveals that: the hydrogen contents in all gas samples can be detected, and the maximum value of hydrogen is 4.8% while the mean value is 0.645%, so the presence of hydrogen in gas is universal. 2 contents of hydrogen exceed 4%, 47 contents are between 2%-4% and 206 contents are between 1%-2%, thus, the content of hydrogen in gas is roughly the same with the content of heavy hydrocarbon in gas. It is suggested that: more attentions should be given to the hydrogen in gas to be an important index of coal and gas outburst and to be an important index of gas explosion, safety of coal storage and transportation.
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Authors: Teruto Kanadani, Norihito Nagata, Makoto Hino, Koji Murakami, Keitaro Horikawa, Keiyu Nakagawa, Minoru Fukuhara
Abstract: In this study, the effect of electroless Ni-P plating on the mechanical properties of Al-4%Ge alloy was investigated. As the results, the following points were clarified. (i) Tensile strength of the specimen subjected to the Ni-P plating after aging treatment or furnace cooling treatment was improved by about 10% in comparison to one of the non-processed specimens. (ii) Breaking elongation of the specimen subjected to the Ni-P plating after aging treatment showed no significant changes in comparison to one of the non-processed specimens. On the other hand, breaking elongation of the specimen subjected to Ni-P plating after a furnace cooling treatment was reduced to 70% in comparison to one of the non-processed specimens. (iii) Fatigue strength of the specimen subjected to the Ni-P plating after a furnace cooling treatment was overall reduced rather than one of non-processed specimens. (iv) Fatigue strength of the specimen subjected to the Ni-P plating after aging treatment was overall reduced, except for the low-stress region, rather than one of the non-processed specimens. (v) In the specimen subjected to Ni-P plating after a furnace cooling treatment or aging treatment, clear hydrogen desorption was recognized. On the other hand, there was only hydrogen desorption from a few of the non-processed specimens. Especially, it is considered that the poor fatigue strength and ductility of the plating materials are mainly due to the interaction between the surface precipitates and hydrogen gas.
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Authors: Norihito Nagata, Teruto Kanadani, Minoru Fukuhara, Makoto Hino, Koji Murakami
Abstract: In this study, the effect of electroless Ni-P plating on the fatigue strength of dilute Al-Si alloys was investigated. As results, the following points were clarified. Fatigue strength of the specimen subjected to zincate treatment only after furnace cooling treatment was almost the same as the furnace cooling only. Fatigue strength of the specimen subjected to Ni-P plating after furnace cooling treatment, was reduced overall, except for high-stress region, rather than one of non-processing materials. Fatigue strength of the specimen subjected to Ni-P plating after aging treatment showed a clear increase in comparison with one of non-processing materials. Breaking elongation of the specimen subjected to Ni-P plating after aging treatment showed no significant changes in comparison with one of non-processing materials. On the other hand, breaking elongation of the specimen subjected to Ni-P plating after furnace cooling treatment reduced by half in comparison with one of non-processing materials. Especially, it seems that poor fatigue strength and ductility of plating materials are mainly caused due to interaction between surface precipitates and hydrogen gas.
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Authors: Hisatake Itoga, Hisao Matsunaga, Saburo Matsuoka
Abstract: The fatigue crack growth (FCG) from a small hole in a low alloy steel JIS-SCM435 round bar was investigated using tension-compression fatigue tests in 0.7 MPa hydrogen gas and ambient air. In the higher FCG rate regime (e.g. da/dN > 108 m/cycle), FCG was accelerated in hydrogen gas compared to in air. On the other hand, in the lower FCG rate regime (e.g. da/dN < 108 m/cycle), FCG in hydrogen was rather slower than that in air. There was no noticeable difference in fatigue limits between these two atmospheres. The FCG in the respective atmospheres showed a typical small crack behavior, i.e. the da/dN for small cracks were much greater than those for large cracks obtained by compact tension (CT) specimen when they were compared at the same ΔK level. In order to unify such a discrepancy of FCG behavior between small crack and large crack, the strain intensity factor range ΔKε was adopted. As a result, the da/dN data for various crack sizes was gathered in a narrow band, i.e. the small crack effect was successfully evaluated with the strain intensity. Moreover, the crack growth life was predicted based on the da/dN-ΔKε relation. The reproduced S-N curve showed a conservative agreement with the fatigue life obtained by experiments.
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Authors: C. Dhanasekaran, G. Mohankumar
Abstract: Over the past two decades considerable effort has been taken to develop and introduce new alternate source of energy for the conventional gasoline and diesel. Environmental pollution and uncertainty in cost of petroleum products are the principal driving forces for this movement. The major pollutants from an Diesel engine system are NOx, Smoke, particulate matter, Soot. Several alternative fuels were tried but all of them are carbon based fuels, therefore net carbon based pollutants cannot be reduced. One alternative to carbon-based fuels is hydrogen. Hydrogen a non-carbon fuel only can meet zero emission vehicles standards in future. Hydrogen can be commercially used as a fuel even though it is having a number of technical and economical barriers. Numerous techniques are available for use in C.I. engine such as dual fuel made, by using spark plug, glow plug, DEE as an ignition enhancer. Hydrogen was used in a diesel engine in the dual fuel mode-using diesel as an ignition source in neat form using DEE. In neat form the DEE was introduced in the manifold. In order to have a precise control of hydrogen flow and to avoid the backfire and pre – ignition problems hydrogen was injection in to intake manifold; DEE injection follows the hydrogen injection. DEE mixed with air and flows into the combustion chamber as DEE auto ignites first followed by hydrogen combustion. A single cylinder-four stroke water-cooled naturally aspirated constant speed D.I. diesel engine with a rated output of 3.7 kW at 1500 rpm was used for the experimental purpose. Measurements were taken with respect to the performance, combustion and emission studies.
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Authors: Toshio Nasu, Kazuto Tokumitsu, T. Konno, Kenji Suzuki
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Authors: Chiti M. Tank, Vijaykumar B. Varma, Sudha V. Bhoraskar, Vikas L. Mathe
Abstract: Silicon nanoparticles (Si-NPs) were synthesized using thermal plasma assisted gas phase condensation at different compositions of argon and hydrogen. The content of hydrogen in argon was varied from 0 to 15 mole percent. Synthesized nanoparticles were characterized by Transmission Electron Microscopy (TEM) and Fourier Transform Infrared spectroscopy (FTIR). Noticeable change in the morphology of nanostructures was observed with changing hydrogen content. Si-NPs synthesized in the presence of argon consisted of flake like structures, mostly amorphous. With increase in hydrogen concentration, flake like structures disappeared and prominent spherical structures and nanowires were observed. On further increasing hydrogen content spherical crystalline nanostructures with a tail of nanowire were formed and then nanoplatelets of SiC along with silicon nanostructures were observed. Different parameters that changed owing to different hydrogen concentration, were calculated and it is attempted to predict the cause of changing morphology.
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Authors: Tian Lang Li, Zuo Yu Sun
Abstract: The sharp rise in the development of vehicle industry in China not only promotes both the national economy development and the people living quality, but also aggravates both the national energy security and the environmental issues. Adopting alternative fuels instead of petroleum is commonly regarded as the utmost promising solution, however, which alternative fuel(s) is more suitable for China is still in the argument. The present paper compared the characteristics and performance of hydrogen gas and fossil-based fuels, and pointed that hydrogen gas is more suitable for China than fossil-based fuels.
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