In this study, the effects of hot water temperature on clarity, total soluble solids, polyphenol oxidase (PPO) and color of banana juice during hot water ex-traction were discussed based on the theory in which heat ...In this study, the effects of hot water temperature on clarity, total soluble solids, polyphenol oxidase (PPO) and color of banana juice during hot water ex-traction were discussed based on the theory in which heat treatment might induce the pectin and protein in banana pulp to form insoluble products. The results showed the hot water temperature had a significant effect on the formation of insol-uble polymers in banana pulp from pectin and protein. In 75 ℃ water, the pectin and protein in banana pulp were most inclined to form insoluble products. Under this condition, the clarity of banana juice was also highest. The light transmittance at 660 nm was close to 90%. In the banana juice, extracted by 75 ℃ water, the pectin and protein contents were lowest, and they were lower than 7.3 mg/100 ml and 12.9 mg/100 ml respectively. The 75 ℃ water could not inactivate completely the pectin in banana pulp due to its high heat resistance, Therefore, 0.05% L-cys-teine or ascorbic acid needed to be added into banana pulp to inhibit the browning of juice induced by residual PPO.展开更多
Phase separation rate is a critical character in determining the usefulness of a solvent extraction system in hydrometallurgy. A survey of the synergistic mixture containing dinonylnaphthalene sulfonic acid (HDNNS) an...Phase separation rate is a critical character in determining the usefulness of a solvent extraction system in hydrometallurgy. A survey of the synergistic mixture containing dinonylnaphthalene sulfonic acid (HDNNS) and 2-ethylhexly 4-pyridinecarboxylate ester (4PC) for the extraction of cobalt from acidic single metal sulfate solution was carried out to suggest how the physicochemical properties and the morphology of the reverse micelles in the loaded organic phase affect the phase separation. The results show that effective parameters affecting the phase separation are the viscosity and the excess water uptake of the loaded organic phase. It is obvious that the specific settling rate (SSR) decreases with the apparent increase of these two parameters. The measurement of small angle X-ray scattering (SAXS) proves that the morphology of the reversed micelles in the loaded organic phase changes evidently with the change of the specific settling rate (SSR).展开更多
Miamiensis avidus Thompson & Moewus,1964,is a cosmopolitan and well-known marine pathogenic ciliated protist.However,the taxonomy of this species up to now has remained controversial,especially with respect to the...Miamiensis avidus Thompson & Moewus,1964,is a cosmopolitan and well-known marine pathogenic ciliated protist.However,the taxonomy of this species up to now has remained controversial,especially with respect to the validity of the morphologically similar species,Philasterides dicentrarchi,which was considered as a junior synonym of M.avidus.In this study,a population of M.avidus was collected from the skin of pharaoh cuttlefish(Sepia pharaonis) cultured near the East China Sea,Ningbo,China and its morphology and phylogeny were investigated in detail based on living characters,infraciliature,small subunit(SSU) r DNA and ITS1-5.8 S-ITS2 region sequences.In addition,the morphometrics of a previously reported free-living population,collected from the Bohai Sea,were rechecked and analyzed.We compared the present two isolates with all historic populations of M.avidus and P.dicentrarchi,and found that their morphological characters were either highly similar or exactly identical,indicating that they are the same morphospecies.However,the phylogenetic analyses based on SSU r DNA or ITS1-5.8 S-ITS2 region sequences revealed that most M.avidus and P.dicentrarchi populations formed one clade,and the two isolates of M.avidus from Weifang and American Type Culture Collection clustered in another clade,which indicated that there might be cryptic species in Miamiensis avidus.展开更多
The mixer-settler is a core device of solvent extraction for separating rare earth elements. There are some adverse effects like high rare earth accumulation and poor production efficiency during industrial production...The mixer-settler is a core device of solvent extraction for separating rare earth elements. There are some adverse effects like high rare earth accumulation and poor production efficiency during industrial production. Current researches usually focus on changing the structure of the mixer-settler without making a breakthrough towards gravity clarification. In this paper, in order to improve the efficiency of clarification, a mixer-settler with double stirring mode was designed and manufactured by adding a stirring device in the settler after reducing the volume of the settler. The innovation of this research involves adopting the ultraviolet-visible spectrophotometer to investigate the quantity of aqueous phase entrainment at the settler outlet in order to measure the clarification degree. Experimental results show that the clarification effect with stirring is better than that without stirring. The clarification effect is ameliorated as the stirring speed increases. Generally, the clarification effect shows a best condition when the offset distance is 12.5 cm, making the phase entrainment reduced to less than 0.1%. When the clearance over the tank bottom is 7 cm and 10 cm, respectively, the quantity of aqueous phase entrainment is better than the case with a clearance of 4 cm. The results show that the stirring paddle close to the mixed phase zone can better promote the two-phase separation.展开更多
The main ideas in the development of the solvent extraction mixer settler focused on achieving clean phase separation,minimizing the loss of the reagents and decreasing the surface area of the settlers.The role of baf...The main ideas in the development of the solvent extraction mixer settler focused on achieving clean phase separation,minimizing the loss of the reagents and decreasing the surface area of the settlers.The role of baffles in a mechanically agitated vessel is to ensure even distribution,reduce settler turbulence,promote the stability of power drawn by the impeller and to prevent swirling and vortexing of liquid,thus,greatly improving the mixing of liquid.The insertion of the appropriate number of baffles clearly improves the extent of liquid mixing.However,excessive baffling would interrupt liquid mixing and lengthen the mixing time.Computational fluid dynamics(CFD) provides a tool for determining detailed information on fluid flow(hydrodynamics) which is necessary for modeling subprocesses in mixer settler.A total of 54 final CFD runs were carried out representing different combinations of variables like number of baffles,density and impeller speed.CFD data shows that amount of separation increases with increasing baffles number and decreasing impeller speed.展开更多
Control of clarifier in the activated sludge process is critical for ensuring effective wastewater treatment. This paper is to study appropriate control strategies for a clarifier in an industrial wastewater treatment...Control of clarifier in the activated sludge process is critical for ensuring effective wastewater treatment. This paper is to study appropriate control strategies for a clarifier in an industrial wastewater treatment plant. Five control strategies are proposed, implemented and evaluated in a simulation software (West ++). The sludge blanket height and the effluent suspended solids concentration were proposed as the measured variable. The manipulated variable was the quantity of polymer added to the system. The strategies were evaluated in terms of their ability to maintain the sludge blanket height below 1.5m, their polymer requirements, their sensitivity to poor tuning and the required control action.展开更多
Oil-water separation is critical to solvent extraction process of rare earth, which can directly affect the yield and quality of the product. The experiments measure the two-phase separation time in a beaker, mixing u...Oil-water separation is critical to solvent extraction process of rare earth, which can directly affect the yield and quality of the product. The experiments measure the two-phase separation time in a beaker, mixing uniformity of two phases in the mixer and the oil phase entrainment at oil exit by the Karl Fischer method and numerical simulation for the mixersettler to study the combined effect of gravity and stirring. Experimental results show that relative to the static situation, the separation efficiency resulted from low-speed stirring is increased by 25%. The water content in the oil is a minimum at an offset distance L of 10 cm and the clearance off the tank bottom z of 10 cm is as low as 0.49%. Distribution images of oilwater separation at 2 s indicates that stirring is very conducive to the separation of the oil-water phase.展开更多
The effluent quality from a secondary clarifier in an activated sludge process depends on the performance in the secondary clarifier at great extent. Several models have been developed based on the Kynch solid flux th...The effluent quality from a secondary clarifier in an activated sludge process depends on the performance in the secondary clarifier at great extent. Several models have been developed based on the Kynch solid flux theory to improve the clarifier performance at last decades. This paper proposed a model which is established according to the basis sedimentation process of the secondary clarifier and Kynch flux theory for a clarifier with feedwell in upper of tank and the diffusion effective are combined into the model, which benefts the further improvement of the model and makes the solutions fit to the measurement data in secondary clarifier,展开更多
The present paper presents an algorithm and a program for plotting the clarifying curves and for determination of the specific amount of settled material during the initial period based on data obtained from sedimenta...The present paper presents an algorithm and a program for plotting the clarifying curves and for determination of the specific amount of settled material during the initial period based on data obtained from sedimentation experiments in stationary column of aqueous suspensions of solids particles with different concentrations. The algorithm and program have been developed for an interactive, rapid and convenient processing of the data obtained from sedimentation experiments in stationary column of aqueous suspensions of solids particles and allow obtaining with accuracy of precise and expressive graphs which characterize the behaviour of aqueous suspensions to sedimentation in stationary column. Sedimentation study of different aqueous suspensions of solids particles in stationary column is of great importance for experimentally determining the important parameters required to design and exploitation clarifiers and sludge thickeners from waste water treatment plants.展开更多
The polymerase chain reaction is one of the most useful technical ad- vance and inventions in modern molecular biology. Developed in 1983 by Kary Mullis, PCR is now a common and indispensable technique used in medical...The polymerase chain reaction is one of the most useful technical ad- vance and inventions in modern molecular biology. Developed in 1983 by Kary Mullis, PCR is now a common and indispensable technique used in medical and bi- ology research labs for a variety of applications. A large number of articles relat- ed to PCR are available on the internet and other places. People know well about the basic principle and are very familiar with the procedures of the PCR. But, some details were neglected on the numbers of the target sequence and other DNA strands number after 30 to 35 cycles of the PCR. In most papers, the number of newly synthesized DNA strands including target DNA and non target DNA is am- biguous and even wrong. In this paper, highlights were given to the theoretical number of target DNA number in details and the exact number of the target DNA number can be concluded by analysis.展开更多
基金Supported by the Key Project of the National Twelfth-Five Year Research Program of China(2012BAD31B03)Guangdong Province Science and Technology Project(2011B010100041)~~
文摘In this study, the effects of hot water temperature on clarity, total soluble solids, polyphenol oxidase (PPO) and color of banana juice during hot water ex-traction were discussed based on the theory in which heat treatment might induce the pectin and protein in banana pulp to form insoluble products. The results showed the hot water temperature had a significant effect on the formation of insol-uble polymers in banana pulp from pectin and protein. In 75 ℃ water, the pectin and protein in banana pulp were most inclined to form insoluble products. Under this condition, the clarity of banana juice was also highest. The light transmittance at 660 nm was close to 90%. In the banana juice, extracted by 75 ℃ water, the pectin and protein contents were lowest, and they were lower than 7.3 mg/100 ml and 12.9 mg/100 ml respectively. The 75 ℃ water could not inactivate completely the pectin in banana pulp due to its high heat resistance, Therefore, 0.05% L-cys-teine or ascorbic acid needed to be added into banana pulp to inhibit the browning of juice induced by residual PPO.
基金Project(2014CB643401) supported by the National Basic Research Program of ChinaProject(51674294) supported by the National Natural Science Foundation of ChinaProject(2016TP1007) supported by the Hunan Provincial Science and Technology Plan,China
文摘Phase separation rate is a critical character in determining the usefulness of a solvent extraction system in hydrometallurgy. A survey of the synergistic mixture containing dinonylnaphthalene sulfonic acid (HDNNS) and 2-ethylhexly 4-pyridinecarboxylate ester (4PC) for the extraction of cobalt from acidic single metal sulfate solution was carried out to suggest how the physicochemical properties and the morphology of the reverse micelles in the loaded organic phase affect the phase separation. The results show that effective parameters affecting the phase separation are the viscosity and the excess water uptake of the loaded organic phase. It is obvious that the specific settling rate (SSR) decreases with the apparent increase of these two parameters. The measurement of small angle X-ray scattering (SAXS) proves that the morphology of the reversed micelles in the loaded organic phase changes evidently with the change of the specific settling rate (SSR).
基金supported by the National Natural Science Foundation of China(No.31572230)the Open Fund of Zhejiang Provincial Top Key Discipline of Aqua-culture in Ningbo University(No.xkzsc1417)+1 种基金the K.C.Wong Magna Fund in Ningbo Universitythe Scientific Research Foundation of Graduate School of Ningbo University
文摘Miamiensis avidus Thompson & Moewus,1964,is a cosmopolitan and well-known marine pathogenic ciliated protist.However,the taxonomy of this species up to now has remained controversial,especially with respect to the validity of the morphologically similar species,Philasterides dicentrarchi,which was considered as a junior synonym of M.avidus.In this study,a population of M.avidus was collected from the skin of pharaoh cuttlefish(Sepia pharaonis) cultured near the East China Sea,Ningbo,China and its morphology and phylogeny were investigated in detail based on living characters,infraciliature,small subunit(SSU) r DNA and ITS1-5.8 S-ITS2 region sequences.In addition,the morphometrics of a previously reported free-living population,collected from the Bohai Sea,were rechecked and analyzed.We compared the present two isolates with all historic populations of M.avidus and P.dicentrarchi,and found that their morphological characters were either highly similar or exactly identical,indicating that they are the same morphospecies.However,the phylogenetic analyses based on SSU r DNA or ITS1-5.8 S-ITS2 region sequences revealed that most M.avidus and P.dicentrarchi populations formed one clade,and the two isolates of M.avidus from Weifang and American Type Culture Collection clustered in another clade,which indicated that there might be cryptic species in Miamiensis avidus.
基金supported by Hi-Tech Research and Development Program(863)of China(2010AA03A405)the National Natural Science Foundation of China(No.50974035,No.51004033)
文摘The mixer-settler is a core device of solvent extraction for separating rare earth elements. There are some adverse effects like high rare earth accumulation and poor production efficiency during industrial production. Current researches usually focus on changing the structure of the mixer-settler without making a breakthrough towards gravity clarification. In this paper, in order to improve the efficiency of clarification, a mixer-settler with double stirring mode was designed and manufactured by adding a stirring device in the settler after reducing the volume of the settler. The innovation of this research involves adopting the ultraviolet-visible spectrophotometer to investigate the quantity of aqueous phase entrainment at the settler outlet in order to measure the clarification degree. Experimental results show that the clarification effect with stirring is better than that without stirring. The clarification effect is ameliorated as the stirring speed increases. Generally, the clarification effect shows a best condition when the offset distance is 12.5 cm, making the phase entrainment reduced to less than 0.1%. When the clearance over the tank bottom is 7 cm and 10 cm, respectively, the quantity of aqueous phase entrainment is better than the case with a clearance of 4 cm. The results show that the stirring paddle close to the mixed phase zone can better promote the two-phase separation.
文摘The main ideas in the development of the solvent extraction mixer settler focused on achieving clean phase separation,minimizing the loss of the reagents and decreasing the surface area of the settlers.The role of baffles in a mechanically agitated vessel is to ensure even distribution,reduce settler turbulence,promote the stability of power drawn by the impeller and to prevent swirling and vortexing of liquid,thus,greatly improving the mixing of liquid.The insertion of the appropriate number of baffles clearly improves the extent of liquid mixing.However,excessive baffling would interrupt liquid mixing and lengthen the mixing time.Computational fluid dynamics(CFD) provides a tool for determining detailed information on fluid flow(hydrodynamics) which is necessary for modeling subprocesses in mixer settler.A total of 54 final CFD runs were carried out representing different combinations of variables like number of baffles,density and impeller speed.CFD data shows that amount of separation increases with increasing baffles number and decreasing impeller speed.
文摘Control of clarifier in the activated sludge process is critical for ensuring effective wastewater treatment. This paper is to study appropriate control strategies for a clarifier in an industrial wastewater treatment plant. Five control strategies are proposed, implemented and evaluated in a simulation software (West ++). The sludge blanket height and the effluent suspended solids concentration were proposed as the measured variable. The manipulated variable was the quantity of polymer added to the system. The strategies were evaluated in terms of their ability to maintain the sludge blanket height below 1.5m, their polymer requirements, their sensitivity to poor tuning and the required control action.
基金financially supported by the National 863 Plan (2010AA03A405, and 2012AA062303)the National 973 Plan (2012CBA01205)+2 种基金the National Natural Science Foundation of China (U1202274, 51204040)the National Science and Technology Support Program (2012BAE01B02)Fundamental Research Funds for the Central Universities (N130702001 and N130607001)
文摘Oil-water separation is critical to solvent extraction process of rare earth, which can directly affect the yield and quality of the product. The experiments measure the two-phase separation time in a beaker, mixing uniformity of two phases in the mixer and the oil phase entrainment at oil exit by the Karl Fischer method and numerical simulation for the mixersettler to study the combined effect of gravity and stirring. Experimental results show that relative to the static situation, the separation efficiency resulted from low-speed stirring is increased by 25%. The water content in the oil is a minimum at an offset distance L of 10 cm and the clearance off the tank bottom z of 10 cm is as low as 0.49%. Distribution images of oilwater separation at 2 s indicates that stirring is very conducive to the separation of the oil-water phase.
文摘The effluent quality from a secondary clarifier in an activated sludge process depends on the performance in the secondary clarifier at great extent. Several models have been developed based on the Kynch solid flux theory to improve the clarifier performance at last decades. This paper proposed a model which is established according to the basis sedimentation process of the secondary clarifier and Kynch flux theory for a clarifier with feedwell in upper of tank and the diffusion effective are combined into the model, which benefts the further improvement of the model and makes the solutions fit to the measurement data in secondary clarifier,
文摘The present paper presents an algorithm and a program for plotting the clarifying curves and for determination of the specific amount of settled material during the initial period based on data obtained from sedimentation experiments in stationary column of aqueous suspensions of solids particles with different concentrations. The algorithm and program have been developed for an interactive, rapid and convenient processing of the data obtained from sedimentation experiments in stationary column of aqueous suspensions of solids particles and allow obtaining with accuracy of precise and expressive graphs which characterize the behaviour of aqueous suspensions to sedimentation in stationary column. Sedimentation study of different aqueous suspensions of solids particles in stationary column is of great importance for experimentally determining the important parameters required to design and exploitation clarifiers and sludge thickeners from waste water treatment plants.
文摘The polymerase chain reaction is one of the most useful technical ad- vance and inventions in modern molecular biology. Developed in 1983 by Kary Mullis, PCR is now a common and indispensable technique used in medical and bi- ology research labs for a variety of applications. A large number of articles relat- ed to PCR are available on the internet and other places. People know well about the basic principle and are very familiar with the procedures of the PCR. But, some details were neglected on the numbers of the target sequence and other DNA strands number after 30 to 35 cycles of the PCR. In most papers, the number of newly synthesized DNA strands including target DNA and non target DNA is am- biguous and even wrong. In this paper, highlights were given to the theoretical number of target DNA number in details and the exact number of the target DNA number can be concluded by analysis.