Volume 7A Issue 1, December 2017
Explore articles published in this issue.
Quantitative Evaluation of Carbon-Enriched Stabilised Austenite in Cast Austempered Ductile Iron of Varying Section Thickness
The quantity of carbon-enriched stabilised austenite (γHC) in austempered ductile iron (ADI) with various casting thicknesses was evaluated in this study. Ductile iron grade that conforms to ASTM A536 65-45-12 was cast, specimens of section thickness in the range of 5 to 25 mm were machined, isothermally treated to 820°C austenitising temperature, and austempered at austempering temperature (T ) of 300 and 375°C. The resulting phase distributions A of treated specimens were characterised using X-Ray Diffraction (XRD) method. The patterns of XRD were found to consist of ferrite (α) and austenite (γ) phases. The percentage volume of carbon-enriched stabilised austenite in the ADI decreased as section thickness increased. It was concluded that the carbon-enriched stabilised austenite in ADI depends on the casting section thickness and austempering temperature
Authors: Olawale John Oluyemi, Ibitoye Simeon Ademola and Oluwasegun Kunle Michael.
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Abstract
The quantity of carbon-enriched stabilised austenite (γHC) in austempered ductile iron (ADI) with various casting thicknesses was evaluated in this study. Ductile iron grade that conforms to ASTM A536 65-45-12 was cast, specimens of section thickness in the range of 5 to 25 mm were machined, isothermally treated to 820°C austenitising temperature, and austempered at austempering temperature (T ) of 300 and 375°C. The resulting phase distributions A of treated specimens were characterised using X-Ray Diffraction (XRD) method. The patterns of XRD were found to consist of ferrite (α) and austenite (γ) phases. The percentage volume of carbon-enriched stabilised austenite in the ADI decreased as section thickness increased. It was concluded that the carbon-enriched stabilised austenite in ADI depends on the casting section thickness and austempering temperature
Dissolution Potential of a Nigerian Complex Covellite Ore by Ammonia-Ammonium Chloride Solution
With continuous industrial demands and as the market potential of purified copper in Nigeria and around the world is on the increase, the development of cheap and eco-friendly methods for the processing of mixed and lower grade copper ores become paramount. Consequently, this study examines the effect of ammonia-ammonium chloride concentration, temperature and particle size on the extent of covellite ore dissolution for predicting optimal copper extraction conditions. The results of the dissolution rates were found to be influenced by ammonium ion concentration, reaction temperature and particle size. At optimal leaching conditions, 82.9% of the initial 10 g/L covellite ore reacted within 120 minutes. The un-leached products (~17%) examined by X-ray diffraction was found to contain siliceous impurities that could be processed further to serve as a by-product for some defined industries. In all, the dissolution data was accordingly analysed and found to follow the shrinking core model for the diffusion controlled reaction. The calculated activation energy of 31.16 kJ/mol supported the proposed mechanism, assumed to be first order relation.
Authors: Balogun Ayo F., Baba Alafara A., Abdulkareem Aishat Y., Raji Mustapha A., Olasinde Fausat T., Muhammed Muhammed O. and Adekola Folahan A.
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Abstract
With continuous industrial demands and as the market potential of purified copper in Nigeria and around the world is on the increase, the development of cheap and eco-friendly methods for the processing of mixed and lower grade copper ores become paramount. Consequently, this study examines the effect of ammonia-ammonium chloride concentration, temperature and particle size on the extent of covellite ore dissolution for predicting optimal copper extraction conditions. The results of the dissolution rates were found to be influenced by ammonium ion concentration, reaction temperature and particle size. At optimal leaching conditions, 82.9% of the initial 10 g/L covellite ore reacted within 120 minutes. The un-leached products (~17%) examined by X-ray diffraction was found to contain siliceous impurities that could be processed further to serve as a by-product for some defined industries. In all, the dissolution data was accordingly analysed and found to follow the shrinking core model for the diffusion controlled reaction. The calculated activation energy of 31.16 kJ/mol supported the proposed mechanism, assumed to be first order relation.
Synergistic Effect of Natural and Synthetic Polymers as Drag Reducing Agents in Single Phase Water Flow
One of the most power consuming applications in the process and petroleum industry is the turbulent means of transporting fluid over long distances through pipelines. High pumping energy is required to overcome the occurring frictional pressure drop. An economical approach has been reported where addition of small amount in parts per million (ppm) of high molecular weight polymeric solution can lead to large decrease in pressure drop. Synthetic polymers are more effective in reducing pressure drop (drag reduction, DR), but cannot be degraded easily by biological means. There is the need to combine them with natural polymers to improve DR and reduce their environmental effect. In this study, an experimental flow facility which consists of liquid storage tanks, pumps and unplasticised polyvinylchloride (uPVC) horizontal pipe system with 20 mm ID has been constructed. DR in single phase water flow was investigated using partially hydrolyzed polyacrylamide (HPAM; magnafloc 1011), polyethylene oxide (PEO) and Aloe Vera mucilage (AVM) separately, as well as mixtures of HPAM-AVM and PEO AVM at Reynolds number from 12,916 to 48,871. The master solutions of 2000 ppm and 20000 ppm for HPAM, PEO and AVM respectively and their respective mixtures were used at different concentrations. The pressure drop was measured using mercury U-tube manometer. Drag reduction of 75.2, 78, 82.5 and 83% was obtained by the polymer mixtures, which was higher than the DR of individual polymer alone at all mixing proportions and Reynolds numbers at the same concentration. The observed synergism in DR may be attributed to the increase in the dimension of the macromolecular coil of the polymer mixture solutions due to the presence and rigidity of other polymer molecules.
Authors: Gimba Mohammad M., Edomwonyi-Otu Lawrence, Abubakar Abdulraheem and Nurudeen Yusuf.
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Abstract
One of the most power consuming applications in the process and petroleum industry is the turbulent means of transporting fluid over long distances through pipelines. High pumping energy is required to overcome the occurring frictional pressure drop. An economical approach has been reported where addition of small amount in parts per million (ppm) of high molecular weight polymeric solution can lead to large decrease in pressure drop. Synthetic polymers are more effective in reducing pressure drop (drag reduction, DR), but cannot be degraded easily by biological means. There is the need to combine them with natural polymers to improve DR and reduce their environmental effect. In this study, an experimental flow facility which consists of liquid storage tanks, pumps and unplasticised polyvinylchloride (uPVC) horizontal pipe system with 20 mm ID has been constructed. DR in single phase water flow was investigated using partially hydrolyzed polyacrylamide (HPAM; magnafloc 1011), polyethylene oxide (PEO) and Aloe Vera mucilage (AVM) separately, as well as mixtures of HPAM-AVM and PEO AVM at Reynolds number from 12,916 to 48,871. The master solutions of 2000 ppm and 20000 ppm for HPAM, PEO and AVM respectively and their respective mixtures were used at different concentrations. The pressure drop was measured using mercury U-tube manometer. Drag reduction of 75.2, 78, 82.5 and 83% was obtained by the polymer mixtures, which was higher than the DR of individual polymer alone at all mixing proportions and Reynolds numbers at the same concentration. The observed synergism in DR may be attributed to the increase in the dimension of the macromolecular coil of the polymer mixture solutions due to the presence and rigidity of other polymer molecules.
Characterization of Sulphated Cellulose Nanocrystals as Stabilizer for Magnetite Nanoparticles Synthesis with improved Magnetic Properties.
This work reports on hydrogen bond energy of sulphated cellulose nanocrystals (CNC) obtained from rubber wood (RW) cellulose for effective steric stabilization of magnetite nanoparticles obtained via the modified Massart's method. The particles morphology, structure and crystallite properties were investigated by using microscopic techniques. The magnetic properties of Fe O nanoparticles were investigated by using physical 3 4 property measurement system. The average width of CNC was ≈20 nm with length of between 190 nm-300 nm. Changes in the hydrogen bond energy of the RW cellulose, during acid hydrolysis, were investigated by using the FT-IR hydrogen bonding energy calculation. The CNCs capped Fe O particles synthesized, were 3 4 monodispersed and oval in shape (with average particle diameter of ≈4 nm). The Fe O nanoparticles obtained, 3 4 exhibited superparamagnetic behaviour and saturation magnetization (Ms) of ≈67.5 amu/g
Authors: Omorogbe Stanley O., Ikhuoria Esther U., Igiehon Lauretta I., Agbonlahor Osazuwa G., Ifijen Hilary I., Aigbodion Aireguamen I.
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Abstract
This work reports on hydrogen bond energy of sulphated cellulose nanocrystals (CNC) obtained from rubber wood (RW) cellulose for effective steric stabilization of magnetite nanoparticles obtained via the modified Massart's method. The particles morphology, structure and crystallite properties were investigated by using microscopic techniques. The magnetic properties of Fe O nanoparticles were investigated by using physical 3 4 property measurement system. The average width of CNC was ≈20 nm with length of between 190 nm-300 nm. Changes in the hydrogen bond energy of the RW cellulose, during acid hydrolysis, were investigated by using the FT-IR hydrogen bonding energy calculation. The CNCs capped Fe O particles synthesized, were 3 4 monodispersed and oval in shape (with average particle diameter of ≈4 nm). The Fe O nanoparticles obtained, 3 4 exhibited superparamagnetic behaviour and saturation magnetization (Ms) of ≈67.5 amu/g