Porous Pd42.5Cu30Ni7.5P20 bulk glassy alloy rods with porosities of up to 70% were successfully prepared by high pressure hydrogen of 15 MPa. The melt of Pd42.5Cu30Ni7.5P20 alloy kept under high pressure hydrogen absorbs hydrogen and subsequent water quenching of the melt causes the homogeneous dispersion of hydrogen bubbles, which was resulted from the decrease of hydrogen solubility with decrease of pressure. Annealing the hydrogen bubble containing sample at a supercooled liquid state under vacuum, the bubbles are allowed to expand due to the decrease of viscosity of metallic glass matrix. Pores expansion continues until glassy matrix crystallizes or the equilibration among pressure of the pores, pressure of the atmosphere and surface tension is achieved. By utilizing these phenomena, pores up to 80 μm in diameters are homogeneously distributed over the whole cross-sectional area of a fully glassy matrix. Under compressive deformation, the porous alloys with porosities exceeding 40% did not show macroscopic fracture in a wide compressive strain range up to 0.6 whereas the non-porous alloy fractures instantly after elastic limit of about 0.02. Porous bulk glassy alloys exhibit higher plateau stress, lower Young’s modulus and higher energy absorption capacity compared with the conventional crystalline metal foams.
{"title":"Fabrication of Bulk Glassy Alloy Foams by High Pressure Hydrogen","authors":"T. Wada, A. Inoue","doi":"10.7791/JHTS.34.74","DOIUrl":"https://doi.org/10.7791/JHTS.34.74","url":null,"abstract":"Porous Pd42.5Cu30Ni7.5P20 bulk glassy alloy rods with porosities of up to 70% were successfully prepared by high pressure hydrogen of 15 MPa. The melt of Pd42.5Cu30Ni7.5P20 alloy kept under high pressure hydrogen absorbs hydrogen and subsequent water quenching of the melt causes the homogeneous dispersion of hydrogen bubbles, which was resulted from the decrease of hydrogen solubility with decrease of pressure. Annealing the hydrogen bubble containing sample at a supercooled liquid state under vacuum, the bubbles are allowed to expand due to the decrease of viscosity of metallic glass matrix. Pores expansion continues until glassy matrix crystallizes or the equilibration among pressure of the pores, pressure of the atmosphere and surface tension is achieved. By utilizing these phenomena, pores up to 80 μm in diameters are homogeneously distributed over the whole cross-sectional area of a fully glassy matrix. Under compressive deformation, the porous alloys with porosities exceeding 40% did not show macroscopic fracture in a wide compressive strain range up to 0.6 whereas the non-porous alloy fractures instantly after elastic limit of about 0.02. Porous bulk glassy alloys exhibit higher plateau stress, lower Young’s modulus and higher energy absorption capacity compared with the conventional crystalline metal foams.","PeriodicalId":113412,"journal":{"name":"Journal of High Temperature Society","volume":"57 21","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114051846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An epoch-making incineration plant, which is equipped with a pressurized fluidized-bed combustor coupled to a turbocharger, for the recovery of the energy contained in sewage sludge is proposed. This plant has three main advantages. (1) A pressure vessel is unnecessary because the maximum operating pressure is 0.3 MPa (absolute pressure). The material cost for plant construction can be reduced. (2) CO2 emissions originating from power generation can be decreased because the FDF (Forced Draft Fan) and the IDF (Induced Draft Fan) are omitted. (3) Steam in the flue gas becomes a working fluid of the turbocharger, so that in addition to the combustion air, the surplus air is also generable. Therefore, this proposed plant will not only save energy but also the generate energy. The objective of this study is to elucidate the fundamental combustion characteristics of the sewage sludge using a lab-scale pressurized fluidized bed combustor (PFBC). The tested fuels are de-watered sludge and sawdust. The temperature distribution in the furnace and N2O emissions in the flue gas are experimentally clarified. As the results, for sludge only combustion, the temperature in the sand bed decreases by drying and pyrolysis, and the pyrolysis gas burns in the freeboard so that the temperature rises. On the other hand, the residual char of sawdust after pyrolysis burns stably in the sand bed for the co-firing of sludge and sawdust. Thus the temperature of the co-firing is considerably higher than that of the sludge only combustion. N2O emissions decreases with increasing freeboard temperature, and are controlled by the temperature for all experimental conditions. These data can be utilize to operation the demonstration plant.
{"title":"過給式流動炉における下水汚泥の基礎燃焼特性;過給式流動炉における下水汚泥の基礎燃焼特性;Fundamental Combustion Characteristics of Sewage Sludge in Fluidized Bed Incinerator with Turbocharger","authors":"T. Murakami, Yoshizo Suzuki, Hidekazu Nagasawa, Takafumi Yamamoto, Takami Koseki, Hitoshi Hirose, Shuichi Ochi","doi":"10.7791/JHTS.34.166","DOIUrl":"https://doi.org/10.7791/JHTS.34.166","url":null,"abstract":"An epoch-making incineration plant, which is equipped with a pressurized fluidized-bed combustor coupled to a turbocharger, for the recovery of the energy contained in sewage sludge is proposed. This plant has three main advantages. (1) A pressure vessel is unnecessary because the maximum operating pressure is 0.3 MPa (absolute pressure). The material cost for plant construction can be reduced. (2) CO2 emissions originating from power generation can be decreased because the FDF (Forced Draft Fan) and the IDF (Induced Draft Fan) are omitted. (3) Steam in the flue gas becomes a working fluid of the turbocharger, so that in addition to the combustion air, the surplus air is also generable. Therefore, this proposed plant will not only save energy but also the generate energy. The objective of this study is to elucidate the fundamental combustion characteristics of the sewage sludge using a lab-scale pressurized fluidized bed combustor (PFBC). The tested fuels are de-watered sludge and sawdust. The temperature distribution in the furnace and N2O emissions in the flue gas are experimentally clarified. As the results, for sludge only combustion, the temperature in the sand bed decreases by drying and pyrolysis, and the pyrolysis gas burns in the freeboard so that the temperature rises. On the other hand, the residual char of sawdust after pyrolysis burns stably in the sand bed for the co-firing of sludge and sawdust. Thus the temperature of the co-firing is considerably higher than that of the sludge only combustion. N2O emissions decreases with increasing freeboard temperature, and are controlled by the temperature for all experimental conditions. These data can be utilize to operation the demonstration plant.","PeriodicalId":113412,"journal":{"name":"Journal of High Temperature Society","volume":"121 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128467072","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kazuyoshi Ishii, H. Murata, K. Kuwana, S. Mizuno, A. Morita, T. Ida
Global environment problems have become more and more serious in recent years, and reduction of greenhouse gas emission based on Kyoto Protocol adopted at the 3rd conference of the parties of the United nations Framework Convention on Climate Change (COP3); securement of primary energy source and development of clean and renewable energy sources have been pressingly needed in consideration of the predicted depletion of fossil fuel in the future. In this study, we explore the use of a solidified biomass-derived fuel, having the maximum compressive strength of 100MPa and calorific value of 21MJ/kg, in iron-casting or iron-making processes as an alternative fuel to be mixed with coal coke. This study, carried out for internal observation using a quick-freeze technique, observed an actual working cupola furnace under the 20% alternative coal coke operation condition. After quick freeze of the cupola furnace, the solidified biomass fuel was found to inhabit near the iron-melting zone. Especially, this solidified biomass fuel smoothly changes carbonized fuel through high-density state during the operating process. On the other hand, this study tried to simulate gasification combustion under a high temperature environment instead of actual internal combustion of solidified biomass fuel. These combustion mechanisms were confirmed to be similar to diffusion-flame phenomena in general.
{"title":"Combustion Simulation and Quick-freeze Observation of a Cupola-furnace Process Using a Bio-coke Fuel Based on Tea Scum","authors":"Kazuyoshi Ishii, H. Murata, K. Kuwana, S. Mizuno, A. Morita, T. Ida","doi":"10.7791/JHTS.35.91","DOIUrl":"https://doi.org/10.7791/JHTS.35.91","url":null,"abstract":"Global environment problems have become more and more serious in recent years, and reduction of greenhouse gas emission based on Kyoto Protocol adopted at the 3rd conference of the parties of the United nations Framework Convention on Climate Change (COP3); securement of primary energy source and development of clean and renewable energy sources have been pressingly needed in consideration of the predicted depletion of fossil fuel in the future. In this study, we explore the use of a solidified biomass-derived fuel, having the maximum compressive strength of 100MPa and calorific value of 21MJ/kg, in iron-casting or iron-making processes as an alternative fuel to be mixed with coal coke. This study, carried out for internal observation using a quick-freeze technique, observed an actual working cupola furnace under the 20% alternative coal coke operation condition. After quick freeze of the cupola furnace, the solidified biomass fuel was found to inhabit near the iron-melting zone. Especially, this solidified biomass fuel smoothly changes carbonized fuel through high-density state during the operating process. On the other hand, this study tried to simulate gasification combustion under a high temperature environment instead of actual internal combustion of solidified biomass fuel. These combustion mechanisms were confirmed to be similar to diffusion-flame phenomena in general.","PeriodicalId":113412,"journal":{"name":"Journal of High Temperature Society","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128781186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Kajimoto, T. Hata, M. Tagawa, H. Kojima, Y. Imamura, H. Hayakawa, H. Yamakawa, Y. Ueda
An analysis of the erosional properties of carbonized lignin with a Si content of 0 to 40% under the simulated atomic oxygen (AO) conditions found in low earth orbit was carried out. The AO environment was produced using a laser detonation atomic oxygen beam source. X-ray photoelectron spectroscopy revealed an increase in the atomic concentration of oxygen-related groups on the surface of the carbonized lignin with and without Si. The erosion rate was found to be low for the case of carbonized lignin with >20% Si. The Si-free sample exhibited a resistance to oxidation due to the formation of an oxide area that protected it from further AO effects on chemical bonds such as C=C bonds. The surface chemistry of the Si-free samples was similar to that of diamondlike carbon (DLC). These experimental results suggest that carbonized lignin derived from Sugi wood has the potential to be used in materials for space applications.
{"title":"Resistance for Erosion on Carbonized Lignin and Si in Combined Materials","authors":"T. Kajimoto, T. Hata, M. Tagawa, H. Kojima, Y. Imamura, H. Hayakawa, H. Yamakawa, Y. Ueda","doi":"10.7791/JHTS.36.185","DOIUrl":"https://doi.org/10.7791/JHTS.36.185","url":null,"abstract":"An analysis of the erosional properties of carbonized lignin with a Si content of 0 to 40% under the simulated atomic oxygen (AO) conditions found in low earth orbit was carried out. The AO environment was produced using a laser detonation atomic oxygen beam source. X-ray photoelectron spectroscopy revealed an increase in the atomic concentration of oxygen-related groups on the surface of the carbonized lignin with and without Si. The erosion rate was found to be low for the case of carbonized lignin with >20% Si. The Si-free sample exhibited a resistance to oxidation due to the formation of an oxide area that protected it from further AO effects on chemical bonds such as C=C bonds. The surface chemistry of the Si-free samples was similar to that of diamondlike carbon (DLC). These experimental results suggest that carbonized lignin derived from Sugi wood has the potential to be used in materials for space applications.","PeriodicalId":113412,"journal":{"name":"Journal of High Temperature Society","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114631989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The material thermal processing using the nano-technology is now advanced towards more precise and controllable smart stage. Regarding plasma processing, plasma system with high precise, has been expected for smart thermal processing. A gas tunnel type plasma system exhibits high energy density and also high efficiency. One practical application of plasma processing is thermal spraying of ceramics such as Al 2 O 3 and ZrO 2 . The characteristics of these ceramic coatings were superior to the conventional ones. The ZrO 2 composite coating has the possibility of the development of high functionally graded TBC (thermal barrier coating). In this paper, the performance such as the mechanical properties, thermal behavior and high temperature oxidation resistance of the alumina/zirconia functionally graded TBCs produced by gas tunnel type plasma spraying was described and discussed. The results showed that the alumina/zirconia composite system exhibited the improvement of mechanical properties and oxidation resistance. Now, one of the advanced plasma application is expected to obtain the desired characteristics of ceramics with improved corrosion resistance, thermal resistance, and wear resistance. One application of the smart coating technology is a formation of Hydroxiapatite coating for bio-medical application, and another is the metallic glass coating with high function.
{"title":"Fabrication of Hybrid Functionally Coating by Gas Tunnel Type Plasma Spraying","authors":"A. Kobayashi","doi":"10.7791/JHTS.34.262","DOIUrl":"https://doi.org/10.7791/JHTS.34.262","url":null,"abstract":"The material thermal processing using the nano-technology is now advanced towards more precise and controllable smart stage. Regarding plasma processing, plasma system with high precise, has been expected for smart thermal processing. A gas tunnel type plasma system exhibits high energy density and also high efficiency. One practical application of plasma processing is thermal spraying of ceramics such as Al 2 O 3 and ZrO 2 . The characteristics of these ceramic coatings were superior to the conventional ones. The ZrO 2 composite coating has the possibility of the development of high functionally graded TBC (thermal barrier coating). In this paper, the performance such as the mechanical properties, thermal behavior and high temperature oxidation resistance of the alumina/zirconia functionally graded TBCs produced by gas tunnel type plasma spraying was described and discussed. The results showed that the alumina/zirconia composite system exhibited the improvement of mechanical properties and oxidation resistance. Now, one of the advanced plasma application is expected to obtain the desired characteristics of ceramics with improved corrosion resistance, thermal resistance, and wear resistance. One application of the smart coating technology is a formation of Hydroxiapatite coating for bio-medical application, and another is the metallic glass coating with high function.","PeriodicalId":113412,"journal":{"name":"Journal of High Temperature Society","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134369357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"ロケットにおける測定技術;ロケットにおける測定技術;Measurements for Rocket Vehicles","authors":"Takashi Maemura, Takanobu Kamiya","doi":"10.7791/JHTS.34.220","DOIUrl":"https://doi.org/10.7791/JHTS.34.220","url":null,"abstract":"","PeriodicalId":113412,"journal":{"name":"Journal of High Temperature Society","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125203652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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