The Experts below are selected from a list of 37023 Experts worldwide ranked by ideXlab platform
Y F Yang - One of the best experts on this subject based on the ideXlab platform.
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a simple route to fabricate tic tib2 ni composite via thermal explosion reaction assisted with external pressure in air
Materials Chemistry and Physics, 2014Co-Authors: Y F Yang, Dekui Mu, Q JiangAbstract:The dense TiC-TiB2/Ni composite was successfully fabricated through the pressure-assisted thermal explosion reaction from Ti, B4C and Ni powder blends in air. The Ignition Temperature (625 degrees C) in air was 415 degrees C lower than that in vacuum. The decreased Ignition Temperature resulted from a chemical oven mechanism in which the oxidation and nitrification of Ti and the oxidation of B4C released the heat and promoted the occurrence of the thermal explosion reaction. The composites prepared in air and vacuum had similar phase constituents and microstructure. Moreover, the composite prepared in air possessed comparable hardness, flexural strength and fracture toughness to the composite prepared in vacuum.
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rapid dehydrogenation of tih2 and its effect on formation mechanism of tic during self propagation high Temperature synthesis from tih2 c system
Powder Technology, 2013Co-Authors: Y F YangAbstract:Abstract Single-phase TiC was rapidly synthesized by self-propagation high-Temperature synthesis (SHS) reaction of TiH2–C powder blends without preliminary dehydrogenation. TiH2 resulted in lower Ignition Temperature, finer TiC particles and lower impurity contents than Ti. In addition, the mechanical properties of bulk TiC material made from TiH2–C were significantly improved. These were closely related to dehydrogenation of TiH2 during the Ignition of SHS.
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reaction behaviour microstructure and mechanical properties of tic tib2 ni composite fabricated by pressure assisted self propagating high Temperature synthesis in air and vacuum
Materials & Design, 2013Co-Authors: Y F Yang, Q JiangAbstract:The dense TiC–TiB2/Ni composite was successfully fabricated via a simple route where the pressure assisted self-propagating high-Temperature synthesis (SHS) was directly ignited at 625 °C with the incorporation of air. The Ignition Temperature in air was much lower than that in vacuum (1040 °C). The composites made in air possessed the similar phase constituents and microstructure as well as comparable mechanical properties to those made in vacuum. The Ignition Temperature both in air and vacuum showed a significant dependence on Ni content and reactant particle size while the reaction products only showed a dependence on Ni content and B4C particle size, irrespective of Ti particle size. The density of the composite made in air and vacuum only depended on Ni content while the mechanical properties of the composites made in air and vacuum both showed a similar dependence on the Ni content and reactant particle size.
Q Jiang - One of the best experts on this subject based on the ideXlab platform.
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a simple route to fabricate tic tib2 ni composite via thermal explosion reaction assisted with external pressure in air
Materials Chemistry and Physics, 2014Co-Authors: Y F Yang, Dekui Mu, Q JiangAbstract:The dense TiC-TiB2/Ni composite was successfully fabricated through the pressure-assisted thermal explosion reaction from Ti, B4C and Ni powder blends in air. The Ignition Temperature (625 degrees C) in air was 415 degrees C lower than that in vacuum. The decreased Ignition Temperature resulted from a chemical oven mechanism in which the oxidation and nitrification of Ti and the oxidation of B4C released the heat and promoted the occurrence of the thermal explosion reaction. The composites prepared in air and vacuum had similar phase constituents and microstructure. Moreover, the composite prepared in air possessed comparable hardness, flexural strength and fracture toughness to the composite prepared in vacuum.
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reaction behaviour microstructure and mechanical properties of tic tib2 ni composite fabricated by pressure assisted self propagating high Temperature synthesis in air and vacuum
Materials & Design, 2013Co-Authors: Y F Yang, Q JiangAbstract:The dense TiC–TiB2/Ni composite was successfully fabricated via a simple route where the pressure assisted self-propagating high-Temperature synthesis (SHS) was directly ignited at 625 °C with the incorporation of air. The Ignition Temperature in air was much lower than that in vacuum (1040 °C). The composites made in air possessed the similar phase constituents and microstructure as well as comparable mechanical properties to those made in vacuum. The Ignition Temperature both in air and vacuum showed a significant dependence on Ni content and reactant particle size while the reaction products only showed a dependence on Ni content and B4C particle size, irrespective of Ti particle size. The density of the composite made in air and vacuum only depended on Ni content while the mechanical properties of the composites made in air and vacuum both showed a similar dependence on the Ni content and reactant particle size.
Chunzhu Li - One of the best experts on this subject based on the ideXlab platform.
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an investigation of the causes of the difference in coal particle Ignition Temperature between combustion in air and in o2 co2
Fuel, 2010Co-Authors: Yu Qiao, Lian Zhang, Eleanor Binner, Minghou Xu, Chunzhu LiAbstract:Abstract The Ignition Temperatures of a Loy Yang brown coal and a Datong bituminous coal were investigated in a wire-mesh reactor where the secondary reactions of the evolved volatiles were minimised. An increase in the average particle Ignition Temperature of 21 °C was observed for the brown coal when air (21% O 2 + 79% N 2 ) was replaced with a mixture of 21% O 2 + 79% CO 2 . Combustion was also carried out in the mixtures of 21% O 2 + 79% argon and 21%O 2 + 79% helium in order to determine the effects of heat transfer on the observed particle Ignition Temperature. It is concluded that the thermal conductivity of gas atmosphere surrounding the particles greatly influences the observed particle Ignition Temperature while the effects of the heat capacity of the gas atmosphere was very minor under our experimental conditions. The structure of char and the reactions involving the char (char-O 2 and char-CO 2 ) can greatly affect the observed particle Ignition Temperature. In particular, the char-CO 2 reactions were largely responsible for the observed difference in particle Ignition Temperature in air and in 21% O 2 + 79% CO 2 . Alkali and alkaline earth metallic (AAEM) species in the brown coal also significantly affect the observed particle Ignition Temperature.
Yaqing Li - One of the best experts on this subject based on the ideXlab platform.
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risk evaluation of coal spontaneous combustion on the basis of auto Ignition Temperature
Fuel, 2018Co-Authors: Yutao Zhang, Weifeng Wang, Chaoping Yang, Yaqing LiAbstract:Abstract The spontaneous combustion of coal, if not eradicated immediately, may lead to coal Ignition and even a full-blown fire. A new method, DSC Inflection Point (DSCIP), was proposed to determine the coal auto-Ignition Temperature (CAIT). Heat fluxes and kinetic parameters before and after CAIT were comparatively investigated through TG/DSC analysis and mathematical model construction. Meanwhile, the impacts of Temperature rise rate and oxygen concentration on CAIT were studied and two indexes representing the hazard and destructiveness of coal spontaneous combustion, respectively, were proposed. The results demonstrated that the heat flux curve of coal spontaneous combustion can be well fitted using Gaussian mixture model. Compared to the oxidation stage, the released heat during the combustion stage was greatly increased. Furthermore, the activation energy became larger and the reaction order decreased to zero when the Temperature exceeded CAIT. The study also found that CAIT was enhanced with the increase of Temperature rise rates or the decrease of oxygen concentrations. Changes of heat flux, free radicals, and the activation energy proved the rationality and feasibility of the DSCIP method in determining CAIT. Additionally, under the same environmental conditions, lignite had the largest hazard of coal spontaneous combustion and the anthracite had the biggest destructiveness. Both the hazard and the destructiveness of coal spontaneous combustion became stronger as oxygen concentrations increased.
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characteristics of mass heat and gaseous products during coal spontaneous combustion using tg dsc ftir technology
Journal of Thermal Analysis and Calorimetry, 2018Co-Authors: Yutao Zhang, Yaqing Li, Yao Huang, Shanshan Li, Weifeng WangAbstract:Spontaneous combustion, if not eradicated immediately, may lead to coal Ignition and even a full-blown fire. An understanding of the characteristics of coal oxidation under various environmental conditions is conducive to the reveal of the mechanism and the prevention of coal spontaneous combustion. TG/DSC–FTIR coupling technology was employed to investigate the evolutions of coal mass, heat and gaseous products during coal spontaneous combustion. The experiments conclude that the mass loss rate in Combustion Stage was much higher than other stages and the major of coal mass (over 80%) was consumed at this stage. As the oxygen concentration decreased, the combustion of coal was evidently postponed and the exothermic region shifted to a higher Temperature. Correspondingly, the Temperatures at which productions of CO and CO2 reached to the maximum were deferred as well. Experimental results also indicated that heating rates behaved differently before and after the Ignition Temperature. The mass loss rates of coal were independent of heating rates before Ignition Temperatures but obviously expanded and moved to higher Temperatures after exceeding the Ignition Temperature. Additionally, with the increase of the heating rates, the exothermic region shifted to higher Temperatures and the release of CO and CO2 were delayed and reached to the maximum in a longer time.
Yutao Zhang - One of the best experts on this subject based on the ideXlab platform.
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risk evaluation of coal spontaneous combustion on the basis of auto Ignition Temperature
Fuel, 2018Co-Authors: Yutao Zhang, Weifeng Wang, Chaoping Yang, Yaqing LiAbstract:Abstract The spontaneous combustion of coal, if not eradicated immediately, may lead to coal Ignition and even a full-blown fire. A new method, DSC Inflection Point (DSCIP), was proposed to determine the coal auto-Ignition Temperature (CAIT). Heat fluxes and kinetic parameters before and after CAIT were comparatively investigated through TG/DSC analysis and mathematical model construction. Meanwhile, the impacts of Temperature rise rate and oxygen concentration on CAIT were studied and two indexes representing the hazard and destructiveness of coal spontaneous combustion, respectively, were proposed. The results demonstrated that the heat flux curve of coal spontaneous combustion can be well fitted using Gaussian mixture model. Compared to the oxidation stage, the released heat during the combustion stage was greatly increased. Furthermore, the activation energy became larger and the reaction order decreased to zero when the Temperature exceeded CAIT. The study also found that CAIT was enhanced with the increase of Temperature rise rates or the decrease of oxygen concentrations. Changes of heat flux, free radicals, and the activation energy proved the rationality and feasibility of the DSCIP method in determining CAIT. Additionally, under the same environmental conditions, lignite had the largest hazard of coal spontaneous combustion and the anthracite had the biggest destructiveness. Both the hazard and the destructiveness of coal spontaneous combustion became stronger as oxygen concentrations increased.
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characteristics of mass heat and gaseous products during coal spontaneous combustion using tg dsc ftir technology
Journal of Thermal Analysis and Calorimetry, 2018Co-Authors: Yutao Zhang, Yaqing Li, Yao Huang, Shanshan Li, Weifeng WangAbstract:Spontaneous combustion, if not eradicated immediately, may lead to coal Ignition and even a full-blown fire. An understanding of the characteristics of coal oxidation under various environmental conditions is conducive to the reveal of the mechanism and the prevention of coal spontaneous combustion. TG/DSC–FTIR coupling technology was employed to investigate the evolutions of coal mass, heat and gaseous products during coal spontaneous combustion. The experiments conclude that the mass loss rate in Combustion Stage was much higher than other stages and the major of coal mass (over 80%) was consumed at this stage. As the oxygen concentration decreased, the combustion of coal was evidently postponed and the exothermic region shifted to a higher Temperature. Correspondingly, the Temperatures at which productions of CO and CO2 reached to the maximum were deferred as well. Experimental results also indicated that heating rates behaved differently before and after the Ignition Temperature. The mass loss rates of coal were independent of heating rates before Ignition Temperatures but obviously expanded and moved to higher Temperatures after exceeding the Ignition Temperature. Additionally, with the increase of the heating rates, the exothermic region shifted to higher Temperatures and the release of CO and CO2 were delayed and reached to the maximum in a longer time.
