The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
Chang Whan Joo - One of the best experts on this subject based on the ideXlab platform.
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Effect of filler–filler interaction on Rheological Behaviour of natural rubber compounds filled with both carbon black and silica
Polymer International, 2003Co-Authors: Sungseen Choi, Changwoon Nah, Seung Goo Lee, Chang Whan JooAbstract:Rubber compounds are reinforced with fillers such as carbon black and silica. In general, filled rubber compounds show smooth Rheological Behaviour in measurement of Mooney viscosity or Mooney scorch time. Variation in Rheological Behaviour was studied in terms of the filler composition using natural rubber compounds filled with both carbon black and silica (carbon black/silica = 60/20,40/40, and 20/60 phr). The compound filled with carbon black/silica of 60/20 phr showed normal Rheological Behaviour. However, the compounds filled with carbon black/silica of 40/40 and 20/60 phr showed abnormal Rheological Behaviour, in which the viscosity increased suddenly and then decreased at a certain point during the measurement. The abnormal Behaviour was explained by the strong filler–filler interaction of silica. Moreover, the abnormal Rheological Behaviour was displayed more clearly as the storage time of compounds is increased. © 2003 Society of Chemical Industry
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effect of filler filler interaction on Rheological Behaviour of natural rubber compounds filled with both carbon black and silica
Polymer International, 2003Co-Authors: Sungseen Choi, Changwoon Nah, Seung Goo Lee, Chang Whan JooAbstract:Rubber compounds are reinforced with fillers such as carbon black and silica. In general, filled rubber compounds show smooth Rheological Behaviour in measurement of Mooney viscosity or Mooney scorch time. Variation in Rheological Behaviour was studied in terms of the filler composition using natural rubber compounds filled with both carbon black and silica (carbon black/silica = 60/20,40/40, and 20/60 phr). The compound filled with carbon black/silica of 60/20 phr showed normal Rheological Behaviour. However, the compounds filled with carbon black/silica of 40/40 and 20/60 phr showed abnormal Rheological Behaviour, in which the viscosity increased suddenly and then decreased at a certain point during the measurement. The abnormal Behaviour was explained by the strong filler–filler interaction of silica. Moreover, the abnormal Rheological Behaviour was displayed more clearly as the storage time of compounds is increased. © 2003 Society of Chemical Industry
John F. Kennedy - One of the best experts on this subject based on the ideXlab platform.
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Rheological Behaviour of chitin in NaOH/urea aqueous solution
Carbohydrate Polymers, 2011Co-Authors: Yufeng Tang, Qun Wang, Jianhong Yang, John F. KennedyAbstract:Abstract The Rheological Behaviour of chitin in 8 wt% NaOH/4 wt% urea aqueous medium was evaluated by steady shear and dynamic oscillatory tests, in which the effects of concentration, temperature and time on the Rheological Behaviour of chitin aqueous solution were investigated in detail. It suggested that chitin aqueous solution is sensitive to temperature, which will transform to a gel when temperature increases to physiological conditions. And the higher the concentration is, the lower the gelation temperature is. The comparison on Rheological Behaviour of chitin aqueous solution at different time reveals that 8 wt% NaOH/4 wt% urea solvent at low temperature has little effect on chitin structure. It is interesting that the chitin gel has reversibility and it will transit to solution after being treated at low temperature again. The comparison on Rheological Behaviour between the original chitin aqueous solution and the chitin aqueous solution after gelation reveals that gelation has a little effects on solution properties.
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Rheological Behaviour of chitin in naoh urea aqueous solution
Carbohydrate Polymers, 2011Co-Authors: Yufeng Tang, Qun Wang, Jianhong Yang, John F. KennedyAbstract:Abstract The Rheological Behaviour of chitin in 8 wt% NaOH/4 wt% urea aqueous medium was evaluated by steady shear and dynamic oscillatory tests, in which the effects of concentration, temperature and time on the Rheological Behaviour of chitin aqueous solution were investigated in detail. It suggested that chitin aqueous solution is sensitive to temperature, which will transform to a gel when temperature increases to physiological conditions. And the higher the concentration is, the lower the gelation temperature is. The comparison on Rheological Behaviour of chitin aqueous solution at different time reveals that 8 wt% NaOH/4 wt% urea solvent at low temperature has little effect on chitin structure. It is interesting that the chitin gel has reversibility and it will transit to solution after being treated at low temperature again. The comparison on Rheological Behaviour between the original chitin aqueous solution and the chitin aqueous solution after gelation reveals that gelation has a little effects on solution properties.
Sungseen Choi - One of the best experts on this subject based on the ideXlab platform.
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Effect of filler–filler interaction on Rheological Behaviour of natural rubber compounds filled with both carbon black and silica
Polymer International, 2003Co-Authors: Sungseen Choi, Changwoon Nah, Seung Goo Lee, Chang Whan JooAbstract:Rubber compounds are reinforced with fillers such as carbon black and silica. In general, filled rubber compounds show smooth Rheological Behaviour in measurement of Mooney viscosity or Mooney scorch time. Variation in Rheological Behaviour was studied in terms of the filler composition using natural rubber compounds filled with both carbon black and silica (carbon black/silica = 60/20,40/40, and 20/60 phr). The compound filled with carbon black/silica of 60/20 phr showed normal Rheological Behaviour. However, the compounds filled with carbon black/silica of 40/40 and 20/60 phr showed abnormal Rheological Behaviour, in which the viscosity increased suddenly and then decreased at a certain point during the measurement. The abnormal Behaviour was explained by the strong filler–filler interaction of silica. Moreover, the abnormal Rheological Behaviour was displayed more clearly as the storage time of compounds is increased. © 2003 Society of Chemical Industry
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effect of filler filler interaction on Rheological Behaviour of natural rubber compounds filled with both carbon black and silica
Polymer International, 2003Co-Authors: Sungseen Choi, Changwoon Nah, Seung Goo Lee, Chang Whan JooAbstract:Rubber compounds are reinforced with fillers such as carbon black and silica. In general, filled rubber compounds show smooth Rheological Behaviour in measurement of Mooney viscosity or Mooney scorch time. Variation in Rheological Behaviour was studied in terms of the filler composition using natural rubber compounds filled with both carbon black and silica (carbon black/silica = 60/20,40/40, and 20/60 phr). The compound filled with carbon black/silica of 60/20 phr showed normal Rheological Behaviour. However, the compounds filled with carbon black/silica of 40/40 and 20/60 phr showed abnormal Rheological Behaviour, in which the viscosity increased suddenly and then decreased at a certain point during the measurement. The abnormal Behaviour was explained by the strong filler–filler interaction of silica. Moreover, the abnormal Rheological Behaviour was displayed more clearly as the storage time of compounds is increased. © 2003 Society of Chemical Industry
Yufeng Tang - One of the best experts on this subject based on the ideXlab platform.
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Rheological Behaviour of chitin in NaOH/urea aqueous solution
Carbohydrate Polymers, 2011Co-Authors: Yufeng Tang, Qun Wang, Jianhong Yang, John F. KennedyAbstract:Abstract The Rheological Behaviour of chitin in 8 wt% NaOH/4 wt% urea aqueous medium was evaluated by steady shear and dynamic oscillatory tests, in which the effects of concentration, temperature and time on the Rheological Behaviour of chitin aqueous solution were investigated in detail. It suggested that chitin aqueous solution is sensitive to temperature, which will transform to a gel when temperature increases to physiological conditions. And the higher the concentration is, the lower the gelation temperature is. The comparison on Rheological Behaviour of chitin aqueous solution at different time reveals that 8 wt% NaOH/4 wt% urea solvent at low temperature has little effect on chitin structure. It is interesting that the chitin gel has reversibility and it will transit to solution after being treated at low temperature again. The comparison on Rheological Behaviour between the original chitin aqueous solution and the chitin aqueous solution after gelation reveals that gelation has a little effects on solution properties.
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Rheological Behaviour of chitin in naoh urea aqueous solution
Carbohydrate Polymers, 2011Co-Authors: Yufeng Tang, Qun Wang, Jianhong Yang, John F. KennedyAbstract:Abstract The Rheological Behaviour of chitin in 8 wt% NaOH/4 wt% urea aqueous medium was evaluated by steady shear and dynamic oscillatory tests, in which the effects of concentration, temperature and time on the Rheological Behaviour of chitin aqueous solution were investigated in detail. It suggested that chitin aqueous solution is sensitive to temperature, which will transform to a gel when temperature increases to physiological conditions. And the higher the concentration is, the lower the gelation temperature is. The comparison on Rheological Behaviour of chitin aqueous solution at different time reveals that 8 wt% NaOH/4 wt% urea solvent at low temperature has little effect on chitin structure. It is interesting that the chitin gel has reversibility and it will transit to solution after being treated at low temperature again. The comparison on Rheological Behaviour between the original chitin aqueous solution and the chitin aqueous solution after gelation reveals that gelation has a little effects on solution properties.
Nicky Eshtiaghi - One of the best experts on this subject based on the ideXlab platform.
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Rheological Behaviour of anaerobic digested sludge: impact of concentration and temperature
2013Co-Authors: Nicky Eshtiaghi, J.c. Baudez, Paul SlatterAbstract:Renewable energy is one of the cornerstones of sustainable energy. Biogas from the anaerobic digestion of organic waste materials can provide a clean, easily controlled source of renewable energy, replacing firewood and/or fossil fuels. In order to maintain the requisite constant homogeneous conditions within digesters, operating conditions must be regulated according to the Rheological characteristics of the sludge. An accurate estimate of sludge Rheological properties is required for the design and efficient operation of sludge pumping and digester mixing. In this paper, we have determined the Rheological Behaviour of digested sludge at different concentrations and different temperatures, and highlighted common features. At low shear stress, digested sludge behaves as a viscoelastic solid, but shear banding can occur which modifies the apparent Behaviour. At very high shear stress, the Behaviour fits well with the Bingham model. Finally, we show that the Rheological Behaviour of digested sludge is qualitatively the same at different solids concentrations and temperatures, and depends only on the yield stress and Bingham viscosity: by normalising the shear stress with the yield stress and the shear rate with the yield stress divided by the Bingham viscosity, a master curve was obtained independent of both temperature and concentration. These two parameters (Yield stress and Bingham Viscosity) increase when the solid concentration increases but decrease when the temperature increases. Furthermore, we show that the Rheological Behaviour is irreversibly altered by the thermal history. Dissolution of some of the solids may cause a decrease of the yield stress and an increase of the Bingham viscosity. This result suggests that the solid characteristics decreases with temperature and the usual laws used to describe the thermal evolution of the Rheological Behaviour of fluids are no longer valid with anaerobic digested sludge.
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The impact of temperature on the Rheological Behaviour of anaerobic digested sludge
Chemical Engineering Journal, 2012Co-Authors: J.c. Baudez, Paul Slatter, Nicky EshtiaghiAbstract:The Rheological properties of municipal anaerobic digested sludge rheology are temperature dependent. In this paper, we show that both solid and liquid characteristics decrease with temperature. We also show that the yield stress and the high shear (Bingham) viscosity are the two key parameters determining the Rheological Behaviour. By normalising the shear stress with the yield stress and the shear rate with the yield stress divided by the Bingham viscosity, a master curve was obtained, independent of both temperature and concentration. We also show that the Rheological Behaviour is irreversibly altered by the thermal history. Dissolution of some of the solids may cause a decrease of the yield stress and an increase of the Bingham viscosity. This result suggests that the usual laws used to describe the thermal evolution of the Rheological Behaviour of fluids are no longer valid with anaerobic digested sludge. Finally, the impact of temperature and thermal history have to be taken into account for the design of engineering hydrodynamic processes such as mixing and pumping.
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The Rheological Behaviour of anaerobic digested sludge
Water research, 2011Co-Authors: J.c. Baudez, Flora Markis, Nicky Eshtiaghi, Paul SlatterAbstract:Producing biogas energy from the anaerobic digestion of wastewater sludge is one of the most challenging tasks facing engineers, because they are dealing with vast quantities of fundamentally scientifically poorly understood and unpredictable materials; while digesters need constant flow properties to operate efficiently. An accurate estimate of sludge Rheological properties is required for the design and efficient operation of digestion, including mixing and pumping. In this paper, we have determined the Rheological Behaviour of digested sludge at different concentrations, and highlighted common features. At low shear stress, digested sludge behaves as a linear viscoelastic solid, but shear banding can occur and modify the apparent Behaviour. At very high shear stress, the Behaviour fits well to the Bingham model. Finally, we show that the Rheological Behaviour of digested sludge is qualitatively the same at different solids concentrations, and depends only on the yield stress and Bingham viscosity, both parameters being closely linked to the solids concentration.
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transparent fluids for the Rheological Behaviour of thickened municipal sludge
Chemeca 2011: Engineering a Better World: Sydney Hilton Hotel NSW Australia 18-21 September 2011, 2011Co-Authors: Nicky Eshtiaghi, J.c. Baudez, Flora Markis, Rajarathinam Parthasarathy, Paul SlatterAbstract:Optimizing flow processes in wastewater treatment plants requires that designers and operators take into account flow properties of the sludge. Moreover, due to increasingly more stringent conditions on final disposal avenues such as landfill, composting, incineration etc., practitioners need to produce safer sludge in smaller quantities. Anaerobic digestion is a key treatment process for solids treatment and pathogen reduction. Due to the inherent opacity of sludge, it is impossible to visualize the mixing and flow patterns inside an anaerobic digester. Therefore, choosing an appropriate transparent model fluid which can mimic the Rheological Behaviour of sludge is imperative for visualization of the hydrodynamic functioning of an anaerobic digester. Digested sludge is a complex material with time dependent non-Newtonian thixotropic characteristics. In steady state, it can be modelled by a basic (but truncated) power-law. However, for short-time processes the Herschel-Bulkley model can be used to model liquid-like properties. The objective of this study was to identify model fluids which will mimic the Behaviour of real sludge. A comparison of three model fluids, Carboxymethyl Cellose (CMC), Carbopol gel and laponite clay revealed that these fluids could each model certain aspects of sludge Behaviour. It is concluded that the Rheological Behaviour of sludge can be modelled using CMC in steady state at high shear rates, Carbopol gel for short-time processes and laponite clay suspension for thixotropic.
