The Experts below are selected from a list of 3984 Experts worldwide ranked by ideXlab platform
Zhaoxiang Chen - One of the best experts on this subject based on the ideXlab platform.
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microstructures of laser clad nickel based hardfacing alloys
Surface & Coatings Technology, 1998Co-Authors: Qian Ming, Zhaoxiang ChenAbstract:Abstract Distinctive microstructures of laser-clad passes with three nickel-based hardfacing alloys were observed. The boride-hardened Colmonoy 6 consisted of a structure of γ-nickel dendrites and interdentritic eutectics of γ-nickel, nickel borides and nickel silicides; carbide-hardened Colmonoy 88 consisted of mixed carbides, while WC-strengthened AI-1236 consisted of partially dissolved WC particles embedded in a similar microstructure to Colmonoy 6. For a given laser beam intensity, the microstructures of the clad layers are significantly influenced by the Powder Feed Rate (PFR) employed and, to a lesser extent, the translation speed (TS) of the laser beam. A cellular-to-dendritic transition for Colmonoy 6, a morphology change of the mixed carbide from coarse leaf-like to fine, equiaxed but angular shape for Colmonoy 88, and a lesser degree of dissolution of WC particles for AI-1236 occurred with increasing PFR. At sufficiently high TS, the nucleation and growth of the mixed carbide phases in the Colmonoy 88 layer can be suppressed, especially when the PFR is low. The effect of PFR and TS on the clad microstructure can be understood in terms of the specific energy input ( E S ) and the specific heat energy ( E h ) available, respectively.
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laser cladding of nickel based hardfacing alloys
Surface & Coatings Technology, 1998Co-Authors: Qian Ming, Zhaoxiang ChenAbstract:Abstract The effects of Powder Feed Rate (PFR) and translation speed (TS) of a laser beam were investigated on laser cladding with three nickel-based hardfacing alloys: Colmonoy 6, Colmonoy 88 and AI-1236. The width-to-height ratio of single clad passes and the extent of dilution were found to decrease with increasing PFR and decreasing TS. Microstructurally, Colmonoy 6 clad layers consisted of a nickel-based structure of primary γ-nickel dendrites and interdendritic eutectics of γ-nickel, nickel borides and nickel silicides, Colmonoy 88 of mixed carbides and AI-1236 of partially melted WC particles and mixed carbides embedded in similar nickel-based microstructures. Block-on-ring wear tests showed that the wear mechanism is largely abrasive in nature for all three alloys studied. The wear resistance was found to correlate better with the type and amount of the main hard phase present in the clad layer: AI-1236 clad layers were much superior to those of Colmonoy 6 and Colmonoy 88 clad layers owing to WC particles in the alloy.
Ranjit M. Dhenge - One of the best experts on this subject based on the ideXlab platform.
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twin screw granulation using conveying screws effects of viscosity of granulation liquids and flow of Powders
Powder Technology, 2013Co-Authors: Ranjit M. Dhenge, Kimiaki Washino, James J Cartwrigh, Michael J. Hounslow, Agba D SalmaAbstract:Abstract The effects of increasing viscosity of granulation liquid (amount of binder) at varying Powder Feed Rates on properties of granules and surface velocity of Powder in Twin Screw Granulator (TSG) with conveying screws only were studied. The surface velocities of the dry and wet formulation Powders were obtained using Particle Image Velocimetry (PIV) and Discrete Element Modelling (DEM) simulation. Granulation at both high viscosity of granulation liquid and Powder Feed Rate led to decrease in granule size, voids reduction, increase in strength and compressibility index of granules. The reverse was observed with lowering both viscosity of granulation liquid and Powder Feed Rate. In the PIV study, the dry formulation Powder possessed a higher velocity compared to the wet granules. The surface velocity increased with increasing viscosity of granulation liquid and decreased with increasing Powder Feed Rates. The results helped to qualitatively understand the twin screw granulation process.
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twin screw granulation steps in granule growth
International Journal of Pharmaceutics, 2012Co-Authors: Ranjit M. Dhenge, James J Cartwrigh, Michael J. Hounslow, Agba D SalmaAbstract:The present work focuses on the study of the progression of granules in different compartments along the length of screws in a twin screw granulator (TSG). The effects of varying Powder Feed Rate; liquid to solid ratio and viscosity of granulation liquid on properties of granules was studied. The bigger granules produced at the start of the process were found to change in terms of size, shape and strength along the screw length at all the conditions investigated. The granules became more spherical and their strength increased along the screw length. Tracer granules were also introduced in order to understand the role of kneading and conveying elements in the TSG. The kneading elements promoted consolidation and breakage while the conveying elements led to coalescence, breakage and some consolidation. The results presented here help to provide a qualitative and quantitative understanding of the twin screw granulation process.
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twin screw wet granulation effect of Powder Feed Rate
Advanced Powder Technology, 2011Co-Authors: Ranjit M. Dhenge, Michael J. Hounslow, James J Cartwright, David George Doughty, Agba D SalmanAbstract:Abstract The twin screw extruder has recently become popular as a continuous wet granulation technique. It is logical that granulation using a twin screw granulator will depend on several process variables including Powder Feed Rate but little is known about how these variables will affect the kinetics and mechanisms of granule growth and the eventual structure. The work focuses on understanding how granule properties like structure, surface, strength, dissolution etc., change with varying Powder Feed Rate and attempts to develop the science behind granule formation which ultimately allows a priori process and product design. An attempt has been made to understand the steps involved in granule formation in twin screw granulator. The granules became denser and stronger with an increase in Powder Feed Rate.
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twin screw wet granulation granule properties
Chemical Engineering Journal, 2010Co-Authors: Ranjit M. Dhenge, James J Cartwrigh, Michael J. Hounslow, David George Doughty, Richard S Fyles, Agba D SalmaAbstract:Abstract Granulation is an important particle size enlargement process, used in many applications. Granulation has, for many years, been a batch process because of a greater knowledge base. However, the technique of using a twin screw granulator has been found to be very effective at granulating and is an attractive proposition for manufacturing processes because it can be opeRated continuously. The acceptability of the granules produced varies depending on a number of different parameters. The effect on the properties of granules caused by varying the screw speed, Powder Feed Rate and the ratio of liquid to solid were investigated. This work focuses on the effect that process variables have on the properties of granules and shows that all three-process variables (screw speed, Powder Feed Rate and liquid to solid ratio) had varying influences on residence time and torque, which in turn affected the distribution of size, strength, shape and structure of the granules. For all three-process variables, it was found that by varying the process variables mentioned above resulted in changes to the average particle size distribution. The granules that were produced, however, were irregular, non-spherically shaped granules. The properties of the granules produced by changing each variable in turn were tested and compared in order to determine the optimal conditions for agglomeration using a twin screw granulator, for the used formulation. The ideal conditions will produce to meet the predefined target criteria of mechanically strong and consistent granules, which is important for reliable process operation.
Qian Ming - One of the best experts on this subject based on the ideXlab platform.
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microstructures of laser clad nickel based hardfacing alloys
Surface & Coatings Technology, 1998Co-Authors: Qian Ming, Zhaoxiang ChenAbstract:Abstract Distinctive microstructures of laser-clad passes with three nickel-based hardfacing alloys were observed. The boride-hardened Colmonoy 6 consisted of a structure of γ-nickel dendrites and interdentritic eutectics of γ-nickel, nickel borides and nickel silicides; carbide-hardened Colmonoy 88 consisted of mixed carbides, while WC-strengthened AI-1236 consisted of partially dissolved WC particles embedded in a similar microstructure to Colmonoy 6. For a given laser beam intensity, the microstructures of the clad layers are significantly influenced by the Powder Feed Rate (PFR) employed and, to a lesser extent, the translation speed (TS) of the laser beam. A cellular-to-dendritic transition for Colmonoy 6, a morphology change of the mixed carbide from coarse leaf-like to fine, equiaxed but angular shape for Colmonoy 88, and a lesser degree of dissolution of WC particles for AI-1236 occurred with increasing PFR. At sufficiently high TS, the nucleation and growth of the mixed carbide phases in the Colmonoy 88 layer can be suppressed, especially when the PFR is low. The effect of PFR and TS on the clad microstructure can be understood in terms of the specific energy input ( E S ) and the specific heat energy ( E h ) available, respectively.
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laser cladding of nickel based hardfacing alloys
Surface & Coatings Technology, 1998Co-Authors: Qian Ming, Zhaoxiang ChenAbstract:Abstract The effects of Powder Feed Rate (PFR) and translation speed (TS) of a laser beam were investigated on laser cladding with three nickel-based hardfacing alloys: Colmonoy 6, Colmonoy 88 and AI-1236. The width-to-height ratio of single clad passes and the extent of dilution were found to decrease with increasing PFR and decreasing TS. Microstructurally, Colmonoy 6 clad layers consisted of a nickel-based structure of primary γ-nickel dendrites and interdendritic eutectics of γ-nickel, nickel borides and nickel silicides, Colmonoy 88 of mixed carbides and AI-1236 of partially melted WC particles and mixed carbides embedded in similar nickel-based microstructures. Block-on-ring wear tests showed that the wear mechanism is largely abrasive in nature for all three alloys studied. The wear resistance was found to correlate better with the type and amount of the main hard phase present in the clad layer: AI-1236 clad layers were much superior to those of Colmonoy 6 and Colmonoy 88 clad layers owing to WC particles in the alloy.
Agba D Salma - One of the best experts on this subject based on the ideXlab platform.
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twin screw granulation using conveying screws effects of viscosity of granulation liquids and flow of Powders
Powder Technology, 2013Co-Authors: Ranjit M. Dhenge, Kimiaki Washino, James J Cartwrigh, Michael J. Hounslow, Agba D SalmaAbstract:Abstract The effects of increasing viscosity of granulation liquid (amount of binder) at varying Powder Feed Rates on properties of granules and surface velocity of Powder in Twin Screw Granulator (TSG) with conveying screws only were studied. The surface velocities of the dry and wet formulation Powders were obtained using Particle Image Velocimetry (PIV) and Discrete Element Modelling (DEM) simulation. Granulation at both high viscosity of granulation liquid and Powder Feed Rate led to decrease in granule size, voids reduction, increase in strength and compressibility index of granules. The reverse was observed with lowering both viscosity of granulation liquid and Powder Feed Rate. In the PIV study, the dry formulation Powder possessed a higher velocity compared to the wet granules. The surface velocity increased with increasing viscosity of granulation liquid and decreased with increasing Powder Feed Rates. The results helped to qualitatively understand the twin screw granulation process.
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twin screw granulation steps in granule growth
International Journal of Pharmaceutics, 2012Co-Authors: Ranjit M. Dhenge, James J Cartwrigh, Michael J. Hounslow, Agba D SalmaAbstract:The present work focuses on the study of the progression of granules in different compartments along the length of screws in a twin screw granulator (TSG). The effects of varying Powder Feed Rate; liquid to solid ratio and viscosity of granulation liquid on properties of granules was studied. The bigger granules produced at the start of the process were found to change in terms of size, shape and strength along the screw length at all the conditions investigated. The granules became more spherical and their strength increased along the screw length. Tracer granules were also introduced in order to understand the role of kneading and conveying elements in the TSG. The kneading elements promoted consolidation and breakage while the conveying elements led to coalescence, breakage and some consolidation. The results presented here help to provide a qualitative and quantitative understanding of the twin screw granulation process.
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twin screw wet granulation granule properties
Chemical Engineering Journal, 2010Co-Authors: Ranjit M. Dhenge, James J Cartwrigh, Michael J. Hounslow, David George Doughty, Richard S Fyles, Agba D SalmaAbstract:Abstract Granulation is an important particle size enlargement process, used in many applications. Granulation has, for many years, been a batch process because of a greater knowledge base. However, the technique of using a twin screw granulator has been found to be very effective at granulating and is an attractive proposition for manufacturing processes because it can be opeRated continuously. The acceptability of the granules produced varies depending on a number of different parameters. The effect on the properties of granules caused by varying the screw speed, Powder Feed Rate and the ratio of liquid to solid were investigated. This work focuses on the effect that process variables have on the properties of granules and shows that all three-process variables (screw speed, Powder Feed Rate and liquid to solid ratio) had varying influences on residence time and torque, which in turn affected the distribution of size, strength, shape and structure of the granules. For all three-process variables, it was found that by varying the process variables mentioned above resulted in changes to the average particle size distribution. The granules that were produced, however, were irregular, non-spherically shaped granules. The properties of the granules produced by changing each variable in turn were tested and compared in order to determine the optimal conditions for agglomeration using a twin screw granulator, for the used formulation. The ideal conditions will produce to meet the predefined target criteria of mechanically strong and consistent granules, which is important for reliable process operation.
Michael J. Hounslow - One of the best experts on this subject based on the ideXlab platform.
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twin screw granulation using conveying screws effects of viscosity of granulation liquids and flow of Powders
Powder Technology, 2013Co-Authors: Ranjit M. Dhenge, Kimiaki Washino, James J Cartwrigh, Michael J. Hounslow, Agba D SalmaAbstract:Abstract The effects of increasing viscosity of granulation liquid (amount of binder) at varying Powder Feed Rates on properties of granules and surface velocity of Powder in Twin Screw Granulator (TSG) with conveying screws only were studied. The surface velocities of the dry and wet formulation Powders were obtained using Particle Image Velocimetry (PIV) and Discrete Element Modelling (DEM) simulation. Granulation at both high viscosity of granulation liquid and Powder Feed Rate led to decrease in granule size, voids reduction, increase in strength and compressibility index of granules. The reverse was observed with lowering both viscosity of granulation liquid and Powder Feed Rate. In the PIV study, the dry formulation Powder possessed a higher velocity compared to the wet granules. The surface velocity increased with increasing viscosity of granulation liquid and decreased with increasing Powder Feed Rates. The results helped to qualitatively understand the twin screw granulation process.
-
twin screw granulation steps in granule growth
International Journal of Pharmaceutics, 2012Co-Authors: Ranjit M. Dhenge, James J Cartwrigh, Michael J. Hounslow, Agba D SalmaAbstract:The present work focuses on the study of the progression of granules in different compartments along the length of screws in a twin screw granulator (TSG). The effects of varying Powder Feed Rate; liquid to solid ratio and viscosity of granulation liquid on properties of granules was studied. The bigger granules produced at the start of the process were found to change in terms of size, shape and strength along the screw length at all the conditions investigated. The granules became more spherical and their strength increased along the screw length. Tracer granules were also introduced in order to understand the role of kneading and conveying elements in the TSG. The kneading elements promoted consolidation and breakage while the conveying elements led to coalescence, breakage and some consolidation. The results presented here help to provide a qualitative and quantitative understanding of the twin screw granulation process.
-
twin screw wet granulation effect of Powder Feed Rate
Advanced Powder Technology, 2011Co-Authors: Ranjit M. Dhenge, Michael J. Hounslow, James J Cartwright, David George Doughty, Agba D SalmanAbstract:Abstract The twin screw extruder has recently become popular as a continuous wet granulation technique. It is logical that granulation using a twin screw granulator will depend on several process variables including Powder Feed Rate but little is known about how these variables will affect the kinetics and mechanisms of granule growth and the eventual structure. The work focuses on understanding how granule properties like structure, surface, strength, dissolution etc., change with varying Powder Feed Rate and attempts to develop the science behind granule formation which ultimately allows a priori process and product design. An attempt has been made to understand the steps involved in granule formation in twin screw granulator. The granules became denser and stronger with an increase in Powder Feed Rate.
-
twin screw wet granulation granule properties
Chemical Engineering Journal, 2010Co-Authors: Ranjit M. Dhenge, James J Cartwrigh, Michael J. Hounslow, David George Doughty, Richard S Fyles, Agba D SalmaAbstract:Abstract Granulation is an important particle size enlargement process, used in many applications. Granulation has, for many years, been a batch process because of a greater knowledge base. However, the technique of using a twin screw granulator has been found to be very effective at granulating and is an attractive proposition for manufacturing processes because it can be opeRated continuously. The acceptability of the granules produced varies depending on a number of different parameters. The effect on the properties of granules caused by varying the screw speed, Powder Feed Rate and the ratio of liquid to solid were investigated. This work focuses on the effect that process variables have on the properties of granules and shows that all three-process variables (screw speed, Powder Feed Rate and liquid to solid ratio) had varying influences on residence time and torque, which in turn affected the distribution of size, strength, shape and structure of the granules. For all three-process variables, it was found that by varying the process variables mentioned above resulted in changes to the average particle size distribution. The granules that were produced, however, were irregular, non-spherically shaped granules. The properties of the granules produced by changing each variable in turn were tested and compared in order to determine the optimal conditions for agglomeration using a twin screw granulator, for the used formulation. The ideal conditions will produce to meet the predefined target criteria of mechanically strong and consistent granules, which is important for reliable process operation.