Temperature sensitivity of waxy crude oils makes it difficult to study their flow behaviour in the presence of water especially near their wax appearance temperature （WAT）. In this study a method was proposed and im...Temperature sensitivity of waxy crude oils makes it difficult to study their flow behaviour in the presence of water especially near their wax appearance temperature （WAT）. In this study a method was proposed and implemented to mitigate such difficulties which was applied in predicting mixture temperatures （Tin） of a typical Malaysian waxy crude oil and water flow in a horizontal pipe. To this end, two analytical models were derived firstly from calorimetry equation which based on developed two correlations for defining crude oil heat capacity actualized from the existed specific heat capacities of crude oils. The models were then applied for a set of experiments to reach the defined three predetermined Tm （26 ℃, 28 ℃ and 30 ℃）. The comparison between the predicted mixture temperatures （Tin,1 and Tin,2） from the two models and the experimental results displayed acceptable absolute average errors （0.80% 0.62%, 0.53% for model 1; 0,74%, 0.54%, 0.52% for model 2）. Moreover, the average errors for both models are in the range of standard error limits （4-0,75Z） according to ASTM E230. Conclusively, the proposed model showed the ease of obtaining mixture temperatures close to WAT as predetermined with accuracy of ± 0.5 ℃approximately for over 84% of the examined cases. The method is seen as a practical reference point to further study the flow behaviour of waxy crudes in oil-water two-phase flow system near sensitive temperatures.展开更多
Many zeotropic refrigerant mixtures are proposed as alternatives to some chlorofluorocar-bons (CFCs) and hydrochlorofluorocarbons ( HCFCs). An advantage of zeotropic mixtures is the possibility of reduction in entropy...Many zeotropic refrigerant mixtures are proposed as alternatives to some chlorofluorocar-bons (CFCs) and hydrochlorofluorocarbons ( HCFCs). An advantage of zeotropic mixtures is the possibility of reduction in entropy generation by matching the temperature glidings of refrigerant and heat-transfer fluid in both condenser and evaporator. Zeotropic mixtures are compared with pure re-frigerants to evaluate their exergetic losses. On the other hand, the special phenomena which result from temperature gliding are proved by experiments. A simple equation is obtained, to evaluate dif-ferent zeotropic mixtures' exergetic losses. The maximum flow rate of heat-transfer fluids is found in order that refrigerants phase change can be completed. Lastly, some examples of zeotropic mix-tures ( R407C, R405A and R414B) are given, and their exergetic losses and maximum flow rate of heat-transfer fluids in condenser are forecasted.展开更多
Four-point flexural fatigue test for Gussasphalt mixture specimen was carried out at a straincontrolled mode system. The results showed that the development of the tested stiffness modulus and phase angle of the mixtu...Four-point flexural fatigue test for Gussasphalt mixture specimen was carried out at a straincontrolled mode system. The results showed that the development of the tested stiffness modulus and phase angle of the mixtures with increasing load cycles exhibited three periods, initial generation, slow development and failure period. The fatigue crack generation zone formed in the third period, in which the macro mechanical properties were signifi cantly decreased. Moreover, we also analyzed the effects of asphalt content and mixing temperature on the fatigue life of the mixture. The results showed that the fi rst period when the specimen＇s initial stiffness modulus was reduced to 80% accounted for 5%-10% of the total fatigue life; the second period in which the reduction became slow and demonstrated a liner relationship with load cycles occupied 70%-85% of the fatigue life; and the third period was about 5%-10%. The results indicated that the lower the mixing temperature, the longer the fatigue life of Gussasphalt mixture. Besides, the increasing of asphalt content has a minor effect on the fatigue life of Gussasphalt mixture展开更多
This article describes mathematical models for phase separated mixtures of materials that are in pressure and velocity equilibrium but not necessarily temperature equilibrium. General conditions for constitutive model...This article describes mathematical models for phase separated mixtures of materials that are in pressure and velocity equilibrium but not necessarily temperature equilibrium. General conditions for constitutive models for such mixtures that exhibit a single mixture sound speed are discussed and specific examples are described.展开更多
The viscosities, η, and ultrasonic speeds, u, of pure benzene, triethylamine, （TEA） tributylamine, （TBA）, and those of their binary mixtures, with benzene as common component, covering the whole composition range...The viscosities, η, and ultrasonic speeds, u, of pure benzene, triethylamine, （TEA） tributylamine, （TBA）, and those of their binary mixtures, with benzene as common component, covering the whole composition range have been measured at 278.15 K, 283.15 K, 288.15 K, 293.15 K, 298.15 K, 303.15 K, 308.15 K, 313.15 K, and 318.15 K. From the experimental data the deviations in viscosity, △η, deviations in Gibbs free energy, AG, deviations in ultrasonic speed, △u, deviations in entropies, △S^＊, and deviations in enthalpies, △H^＊, of activation of viscous flow have been determined. The sign and magnitude of these parameters were found to be sensitive towards interactions prevailing in the studied systems. Further, the excess molar volumes, VE, were calculated using data for the binary mixtures. Moreover, theoretical values of viscosities and ultrasonic speeds of the binary mixtures were calculated using different empirical relations and theories. The results were in experimental and theoretical values. discussed in terms of average deviations （AD）展开更多
Green solvents such as water and ionic liquids(ILs)are pillars of the great mansion of green chemistry and green processing.Initially proposed as a new family of ILs,deep eutectic solvents(DESs)have received fast deve...Green solvents such as water and ionic liquids(ILs)are pillars of the great mansion of green chemistry and green processing.Initially proposed as a new family of ILs,deep eutectic solvents(DESs)have received fast development in the past two decades.In this contribution,DESs are reviewed critically and the concept is extended to lowmelting mixture solvents(Lo MMSs),which cover all kinds of materials including ionic compounds,molecular compounds,and metals.Six classes of Lo MMSs are proposed as the new classification system and examples are given.Finally,several thermodynamic issues concerning Lo MMSs are discussed.Two new concepts,robustness of Lo MMSs and high-entropy Lo MMSs,are proposed.展开更多
基金Supported by the Malaysia's Ministry of Higher Education(FRGS/4F136)the University Teknologi Malaysia(RUG/01H68)
文摘Temperature sensitivity of waxy crude oils makes it difficult to study their flow behaviour in the presence of water especially near their wax appearance temperature （WAT）. In this study a method was proposed and implemented to mitigate such difficulties which was applied in predicting mixture temperatures （Tin） of a typical Malaysian waxy crude oil and water flow in a horizontal pipe. To this end, two analytical models were derived firstly from calorimetry equation which based on developed two correlations for defining crude oil heat capacity actualized from the existed specific heat capacities of crude oils. The models were then applied for a set of experiments to reach the defined three predetermined Tm （26 ℃, 28 ℃ and 30 ℃）. The comparison between the predicted mixture temperatures （Tin,1 and Tin,2） from the two models and the experimental results displayed acceptable absolute average errors （0.80% 0.62%, 0.53% for model 1; 0,74%, 0.54%, 0.52% for model 2）. Moreover, the average errors for both models are in the range of standard error limits （4-0,75Z） according to ASTM E230. Conclusively, the proposed model showed the ease of obtaining mixture temperatures close to WAT as predetermined with accuracy of ± 0.5 ℃approximately for over 84% of the examined cases. The method is seen as a practical reference point to further study the flow behaviour of waxy crudes in oil-water two-phase flow system near sensitive temperatures.
基金Supported by National Natural Science Foundation of China( No. 50476062) .
文摘Many zeotropic refrigerant mixtures are proposed as alternatives to some chlorofluorocar-bons (CFCs) and hydrochlorofluorocarbons ( HCFCs). An advantage of zeotropic mixtures is the possibility of reduction in entropy generation by matching the temperature glidings of refrigerant and heat-transfer fluid in both condenser and evaporator. Zeotropic mixtures are compared with pure re-frigerants to evaluate their exergetic losses. On the other hand, the special phenomena which result from temperature gliding are proved by experiments. A simple equation is obtained, to evaluate dif-ferent zeotropic mixtures' exergetic losses. The maximum flow rate of heat-transfer fluids is found in order that refrigerants phase change can be completed. Lastly, some examples of zeotropic mix-tures ( R407C, R405A and R414B) are given, and their exergetic losses and maximum flow rate of heat-transfer fluids in condenser are forecasted.
基金Funded by the National Natural Science Foundation of China(No.51202214)
文摘Four-point flexural fatigue test for Gussasphalt mixture specimen was carried out at a straincontrolled mode system. The results showed that the development of the tested stiffness modulus and phase angle of the mixtures with increasing load cycles exhibited three periods, initial generation, slow development and failure period. The fatigue crack generation zone formed in the third period, in which the macro mechanical properties were signifi cantly decreased. Moreover, we also analyzed the effects of asphalt content and mixing temperature on the fatigue life of the mixture. The results showed that the fi rst period when the specimen＇s initial stiffness modulus was reduced to 80% accounted for 5%-10% of the total fatigue life; the second period in which the reduction became slow and demonstrated a liner relationship with load cycles occupied 70%-85% of the fatigue life; and the third period was about 5%-10%. The results indicated that the lower the mixing temperature, the longer the fatigue life of Gussasphalt mixture. Besides, the increasing of asphalt content has a minor effect on the fatigue life of Gussasphalt mixture
基金supported by the Los Alamos National Laboratory,an affir mative action/equal opportunity employer,operated by Los Alamos National Security,LLC,for the National Nuclear Security Administration of the U.S.Department of Energy under contract DE-AC52-06NA25396
文摘This article describes mathematical models for phase separated mixtures of materials that are in pressure and velocity equilibrium but not necessarily temperature equilibrium. General conditions for constitutive models for such mixtures that exhibit a single mixture sound speed are discussed and specific examples are described.
文摘The viscosities, η, and ultrasonic speeds, u, of pure benzene, triethylamine, （TEA） tributylamine, （TBA）, and those of their binary mixtures, with benzene as common component, covering the whole composition range have been measured at 278.15 K, 283.15 K, 288.15 K, 293.15 K, 298.15 K, 303.15 K, 308.15 K, 313.15 K, and 318.15 K. From the experimental data the deviations in viscosity, △η, deviations in Gibbs free energy, AG, deviations in ultrasonic speed, △u, deviations in entropies, △S^＊, and deviations in enthalpies, △H^＊, of activation of viscous flow have been determined. The sign and magnitude of these parameters were found to be sensitive towards interactions prevailing in the studied systems. Further, the excess molar volumes, VE, were calculated using data for the binary mixtures. Moreover, theoretical values of viscosities and ultrasonic speeds of the binary mixtures were calculated using different empirical relations and theories. The results were in experimental and theoretical values. discussed in terms of average deviations （AD）
基金supported by the National Natural Science Foundation of China(No.22233006)
文摘Green solvents such as water and ionic liquids(ILs)are pillars of the great mansion of green chemistry and green processing.Initially proposed as a new family of ILs,deep eutectic solvents(DESs)have received fast development in the past two decades.In this contribution,DESs are reviewed critically and the concept is extended to lowmelting mixture solvents(Lo MMSs),which cover all kinds of materials including ionic compounds,molecular compounds,and metals.Six classes of Lo MMSs are proposed as the new classification system and examples are given.Finally,several thermodynamic issues concerning Lo MMSs are discussed.Two new concepts,robustness of Lo MMSs and high-entropy Lo MMSs,are proposed.
