The Experts below are selected from a list of 144 Experts worldwide ranked by ideXlab platform
S. Ramanathan - One of the best experts on this subject based on the ideXlab platform.
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synthesis of yag powder by aluminum nitrate yttrium nitrate glycine reaction
Journal of Materials Science Letters, 2002Co-Authors: M B Kakade, S. RamanathanAbstract:Yttrium aluminum garnet (YAG) powders of controlled size distribution find application in the synthesis of optically transparent solid state laser components, advanced engineering materials and composites, etc. [1, 2]. Solution combustion is one of the simple methods for synthesizing the powder. In this technique, from a very concentrated solution of the metal nitrates a very porous sponge-like Oxide Compound is formed due to the evolution of a large amount of gaseous products formed in combustion reaction between an oxidizer (nitrate) and a fuel (urea, glycine etc.) present in the reactant system. The salient feature of combustion reaction is that it is exothermic and self sustaining. In this study the fuel, glycine, is chosen for formation of YAG since the amount of heat evolved and kinetics of the reaction are such that the combustion proceeds smoothly without bursting or spilling out of the product, a desirable aspect from the point of view of scaling up. The Oxide formed is weakly agglomerated and needs to be ground into a fine powder before forming into shape. Formation of amorphous precursors for yttria–alumina Compound phases by the nitrate–glycine reaction (with lean amount of fuel) and evolution of crystalline phases upon heat treatment has been studied by XRD [3]. However a study of the thermal evolution behavior by TG–DTA of the precursors formed by combustion to obtain temperature regimes of weight loss and heat effects (evolution/absorption) before and during crystallization of YAG is essential in obtaining conditions for formation of chemically pure YAG (Y3Al5O12 Oxide Compound). A study of the grinding behavior of the agglomerated mass formed is important from the point of view of its dispersion behavior, as the presence of coarse agglomerates reduces sinterability and homogeneity of microstructure of the product formed. As no study on these aspects has been reported yet for the precursors formed by the nitrates–glycine reaction (with stoichiometric amount of fuel), a detailed investigation of the same has been carried out. The stock solutions of aluminum nitrate (1.54 M) and yttrium nitrate (1.17 M) in the required molar ratio (5 : 3) for a batch size of 20 g. of YAG were placed in a pyrex beaker and the required amount of glycine was added. The ideal molar ratio of fuel (glycine) to oxidizer (nitrate ion) to be used was calculated using the following reaction and is 5/9 or 0.556 (i.e., 5 moles of glycine requires 9 moles of nitrate ions) [4]
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Synthesis of YAG powder by aluminum nitrate–yttrium nitrate–glycine reaction
Journal of Materials Science Letters, 2002Co-Authors: M B Kakade, S. RamanathanAbstract:Yttrium aluminum garnet (YAG) powders of controlled size distribution find application in the synthesis of optically transparent solid state laser components, advanced engineering materials and composites, etc. [1, 2]. Solution combustion is one of the simple methods for synthesizing the powder. In this technique, from a very concentrated solution of the metal nitrates a very porous sponge-like Oxide Compound is formed due to the evolution of a large amount of gaseous products formed in combustion reaction between an oxidizer (nitrate) and a fuel (urea, glycine etc.) present in the reactant system. The salient feature of combustion reaction is that it is exothermic and self sustaining. In this study the fuel, glycine, is chosen for formation of YAG since the amount of heat evolved and kinetics of the reaction are such that the combustion proceeds smoothly without bursting or spilling out of the product, a desirable aspect from the point of view of scaling up. The Oxide formed is weakly agglomerated and needs to be ground into a fine powder before forming into shape. Formation of amorphous precursors for yttria–alumina Compound phases by the nitrate–glycine reaction (with lean amount of fuel) and evolution of crystalline phases upon heat treatment has been studied by XRD [3]. However a study of the thermal evolution behavior by TG–DTA of the precursors formed by combustion to obtain temperature regimes of weight loss and heat effects (evolution/absorption) before and during crystallization of YAG is essential in obtaining conditions for formation of chemically pure YAG (Y3Al5O12 Oxide Compound). A study of the grinding behavior of the agglomerated mass formed is important from the point of view of its dispersion behavior, as the presence of coarse agglomerates reduces sinterability and homogeneity of microstructure of the product formed. As no study on these aspects has been reported yet for the precursors formed by the nitrates–glycine reaction (with stoichiometric amount of fuel), a detailed investigation of the same has been carried out. The stock solutions of aluminum nitrate (1.54 M) and yttrium nitrate (1.17 M) in the required molar ratio (5 : 3) for a batch size of 20 g. of YAG were placed in a pyrex beaker and the required amount of glycine was added. The ideal molar ratio of fuel (glycine) to oxidizer (nitrate ion) to be used was calculated using the following reaction and is 5/9 or 0.556 (i.e., 5 moles of glycine requires 9 moles of nitrate ions) [4]
Crispin H. W. Barnes - One of the best experts on this subject based on the ideXlab platform.
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Magnetic and structural properties of yellow europium Oxide Compound and Eu(OH)3
Journal of Solid State Chemistry, 2015Co-Authors: Dongwook Lee, Jiwon Seo, Luis De Los Santos Valladares, O. Avalos Quispe, Crispin H. W. BarnesAbstract:Abstract A new material based on a yellow europium Oxide Compound was prepared from europium Oxide in a high vacuum environment. The structural and magnetic properties of the material were investigated. Owing to the absence of a crystal structure, the material exhibited a disordered magnetic behavior. In a reaction with deionized (DI) water without applied heat, the Compound assumed a white color as soon as the DI water reached the powder, and the structure became polycrystalline Eu(OH) 3 . The magnetic properties, such as the thermal hysteresis, disappeared after the reaction with DI water, and the magnetic susceptibility of the yellow Oxide Compound weakened. The magnetic properties of Eu(OH) 3 were also examined. Although Eu 3+ is present in Eu(OH) 3 , a high magnetic moment due to the crystal field effect was observed.
Henrik Leion - One of the best experts on this subject based on the ideXlab platform.
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Experimental and Thermodynamic Study on the Interaction of Copper Oxygen Carriers and Oxide Compounds Commonly Present in Ashes
Energy & Fuels, 2019Co-Authors: Esraa Darwish, Duygu Yilmaz, Henrik LeionAbstract:The chemical looping combustion (CLC) and chemical looping oxygen uncoupling (CLOU) processes are unique and efficient methods for the direct separation of carbon diOxide in combustion. In these processes, metal Oxides are used under reducing atmosphere as an oxygen carrier to transfer oxygen between air and a fuel reactor. The fuel is converted by oxygen provided by the oxygen carrier. In the case of using coal or any ash-containing fuel, interaction between coal-derived ash and the oxygen carrier is likely to occur and can lead to deactivation and agglomeration of the oxygen carriers. As the amount of the possible Compounds and compositions of ash can vary widely, thermodynamic equilibrium calculations can be used to represent the formed Compounds during the CLC process to reveal the interaction between the oxygen carrier and the commonly present Oxide Compounds in ash. In this study, the interaction between the Oxide Compounds commonly present in ash and CuO oxygen carriers was studied both experimentally and thermodynamically. CuO is a widely used oxygen carrier with CLOU properties, the ability to release gaseous oxygen under inert atmosphere. Experiments were carried out at 900 degrees C under both oxidizing and inert atmosphere using CuO or Cu2O (CuO/Cu2O) as the oxygen carrier and SiO2, Al2O3, Fe2O3, CaO, and K2O to represent the Oxide Compounds present in ashes. To observe the interaction of the oxygen carriers with each Oxide Compound used, equal moles of copper Oxide and Oxide Compound were mixed. Further, Oxide Compound fractions with the elemental composition relevant to coal ash were mixed with oxygen carriers to investigate the interaction under conditions approaching realistic operation. In all cases, a significant amount of copper Oxides survived without any interaction. However, it was observed that silicate-based formations, especially potassium silicates, lead to strong agglomeration which most likely would decrease the lifetime and oxygen-releasing ability of the oxygen carriers. As the results showed that the thermodynamic equilibrium-based calculations were well in line with the experiments, these calculations can be a good first approach in these types of investigations.
M B Kakade - One of the best experts on this subject based on the ideXlab platform.
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synthesis of yag powder by aluminum nitrate yttrium nitrate glycine reaction
Journal of Materials Science Letters, 2002Co-Authors: M B Kakade, S. RamanathanAbstract:Yttrium aluminum garnet (YAG) powders of controlled size distribution find application in the synthesis of optically transparent solid state laser components, advanced engineering materials and composites, etc. [1, 2]. Solution combustion is one of the simple methods for synthesizing the powder. In this technique, from a very concentrated solution of the metal nitrates a very porous sponge-like Oxide Compound is formed due to the evolution of a large amount of gaseous products formed in combustion reaction between an oxidizer (nitrate) and a fuel (urea, glycine etc.) present in the reactant system. The salient feature of combustion reaction is that it is exothermic and self sustaining. In this study the fuel, glycine, is chosen for formation of YAG since the amount of heat evolved and kinetics of the reaction are such that the combustion proceeds smoothly without bursting or spilling out of the product, a desirable aspect from the point of view of scaling up. The Oxide formed is weakly agglomerated and needs to be ground into a fine powder before forming into shape. Formation of amorphous precursors for yttria–alumina Compound phases by the nitrate–glycine reaction (with lean amount of fuel) and evolution of crystalline phases upon heat treatment has been studied by XRD [3]. However a study of the thermal evolution behavior by TG–DTA of the precursors formed by combustion to obtain temperature regimes of weight loss and heat effects (evolution/absorption) before and during crystallization of YAG is essential in obtaining conditions for formation of chemically pure YAG (Y3Al5O12 Oxide Compound). A study of the grinding behavior of the agglomerated mass formed is important from the point of view of its dispersion behavior, as the presence of coarse agglomerates reduces sinterability and homogeneity of microstructure of the product formed. As no study on these aspects has been reported yet for the precursors formed by the nitrates–glycine reaction (with stoichiometric amount of fuel), a detailed investigation of the same has been carried out. The stock solutions of aluminum nitrate (1.54 M) and yttrium nitrate (1.17 M) in the required molar ratio (5 : 3) for a batch size of 20 g. of YAG were placed in a pyrex beaker and the required amount of glycine was added. The ideal molar ratio of fuel (glycine) to oxidizer (nitrate ion) to be used was calculated using the following reaction and is 5/9 or 0.556 (i.e., 5 moles of glycine requires 9 moles of nitrate ions) [4]
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Synthesis of YAG powder by aluminum nitrate–yttrium nitrate–glycine reaction
Journal of Materials Science Letters, 2002Co-Authors: M B Kakade, S. RamanathanAbstract:Yttrium aluminum garnet (YAG) powders of controlled size distribution find application in the synthesis of optically transparent solid state laser components, advanced engineering materials and composites, etc. [1, 2]. Solution combustion is one of the simple methods for synthesizing the powder. In this technique, from a very concentrated solution of the metal nitrates a very porous sponge-like Oxide Compound is formed due to the evolution of a large amount of gaseous products formed in combustion reaction between an oxidizer (nitrate) and a fuel (urea, glycine etc.) present in the reactant system. The salient feature of combustion reaction is that it is exothermic and self sustaining. In this study the fuel, glycine, is chosen for formation of YAG since the amount of heat evolved and kinetics of the reaction are such that the combustion proceeds smoothly without bursting or spilling out of the product, a desirable aspect from the point of view of scaling up. The Oxide formed is weakly agglomerated and needs to be ground into a fine powder before forming into shape. Formation of amorphous precursors for yttria–alumina Compound phases by the nitrate–glycine reaction (with lean amount of fuel) and evolution of crystalline phases upon heat treatment has been studied by XRD [3]. However a study of the thermal evolution behavior by TG–DTA of the precursors formed by combustion to obtain temperature regimes of weight loss and heat effects (evolution/absorption) before and during crystallization of YAG is essential in obtaining conditions for formation of chemically pure YAG (Y3Al5O12 Oxide Compound). A study of the grinding behavior of the agglomerated mass formed is important from the point of view of its dispersion behavior, as the presence of coarse agglomerates reduces sinterability and homogeneity of microstructure of the product formed. As no study on these aspects has been reported yet for the precursors formed by the nitrates–glycine reaction (with stoichiometric amount of fuel), a detailed investigation of the same has been carried out. The stock solutions of aluminum nitrate (1.54 M) and yttrium nitrate (1.17 M) in the required molar ratio (5 : 3) for a batch size of 20 g. of YAG were placed in a pyrex beaker and the required amount of glycine was added. The ideal molar ratio of fuel (glycine) to oxidizer (nitrate ion) to be used was calculated using the following reaction and is 5/9 or 0.556 (i.e., 5 moles of glycine requires 9 moles of nitrate ions) [4]
Dongwook Lee - One of the best experts on this subject based on the ideXlab platform.
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Magnetic and structural properties of yellow europium Oxide Compound and Eu(OH)3
Journal of Solid State Chemistry, 2015Co-Authors: Dongwook Lee, Jiwon Seo, Luis De Los Santos Valladares, O. Avalos Quispe, Crispin H. W. BarnesAbstract:Abstract A new material based on a yellow europium Oxide Compound was prepared from europium Oxide in a high vacuum environment. The structural and magnetic properties of the material were investigated. Owing to the absence of a crystal structure, the material exhibited a disordered magnetic behavior. In a reaction with deionized (DI) water without applied heat, the Compound assumed a white color as soon as the DI water reached the powder, and the structure became polycrystalline Eu(OH) 3 . The magnetic properties, such as the thermal hysteresis, disappeared after the reaction with DI water, and the magnetic susceptibility of the yellow Oxide Compound weakened. The magnetic properties of Eu(OH) 3 were also examined. Although Eu 3+ is present in Eu(OH) 3 , a high magnetic moment due to the crystal field effect was observed.
